domingo, 11 de dezembro de 2011

DIRETRIZES DO SER HUMANO

Você recebera lições
Você estara matriculado na escola da vida em periodo integral
Você terá oportunidades para aprender a cada dia que passa
Voce podera usar estas oportunidades ou deixá-las passar simplesmente
Não há erros, apenas lições
O crescimento é resultado de um processo de tentativas e erros;
uma experimentação
Os experimentos fracassados são tão parte do processo quanto os experimentos que funcionam
uma lição se repetirá até que tenha sido aprendida
esta lição será apresentada a voce sob várias formas até que vc tenha aprendido
quando conseguir isso, poderá então passar para a próxima lição
se você está vivo, sempre haverá uma lição para aprender
lá não é melhor que aqui
quando o seu lá se transformar em aqui, voce apenas estara obtendo outro lá que, mais uma vez, parecerá melhor que aqui
Os outros são apenas espelhos da sua própria imagem
Voce não pode amar ou detestar alguma coisa em outra pessoa sem que isso reflita alguma coisa
que voce ama ou detesta de si mesmo
É voce quem escolhe o que quer fazer da sua vida
vocÊ tem todas as ferramentas e recursos de que precisa
O que vocÊ faz com eles, é problema seu
a escolha é sua
as respostas estão dentro de vocÊ
as respostas as questões da vida estão dentro de voce
tudo que voce tem a fazer é prestar atenção, ouvir e confiar

CHEMICAL INFORMATION SITES


  1. http://chem.sis.nlm.nih.gov/chemidplus

segunda-feira, 5 de dezembro de 2011

Rodotorula mucilaginosa



Rhodotorula is a pigmented yeast, part of the Basidiomycota phylum, quite easily identifiable by distinctive orange/red colonies when grown on SDA (Sabouraud's Dextrose Agar). This distinctive colour is the result of pigments that the yeast creates to block out certain wavelengths of light that would otherwise be damaging to the cell. Colony colour can vary from being cream coloured to orange/red/pink or yellow.

Rhodotorula is a common environmental inhabitant. It can be cultured from soil, water, and air samples. It is able to scavenge nitrogenous compounds from its environment remarkably well, growing even in air which has been carefully cleaned of any fixed nitrogen contaminants. In such conditions, the nitrogen content of the dry weight of Rhodotorula can drop as low as 1%, compared to around 14% for most bacteria growing in normal conditions. [1]

REF: http://en.wikipedia.org/wiki/Rhodotorula Acessado em 05/12/11

segunda-feira, 10 de outubro de 2011

Rhodococcus spp

Rhodococcus is a genus of aerobic, nonsporulating, nonmotile Gram-positive bacteria closely related to Mycobacteria and Corynebacteria.[1][2] While a few species are pathogenic, most are benign and have been found to thrive in a broad range of environments, including soil, water, and eukaryotic cells.

REF: http://en.wikipedia.org/wiki/Rhodococcus Acessado em 10/10/11

Rhodococcus is a genus of non-motile, non-sporulating, aerobic gram-positive filamentous rods of the phylum Actinobacteria (1). These organisms reside in soil and water environments and are classified as one of the most industrial important organisms. Studies have shown these organisms to grow in both mesophilic (4) and psychrophilic (5) conditions. Strains of Rhodococcus contain enzymes that carry out biologically relevant reactions such as biodesulfurization of fossil fuels, degradation of polychlorinated biphenyls (PCBs), and utilization of a wide variety of other organic compounds as energy sources (4). Therefore, Rhodococcus plays an important role in the global recycling of carbon. Additionally, Rhododcoccus is used commercially as a biocatalyst in the production of fossil fuels, bioactive steroids, and acrylamide (1). The production of dioxygenases by Rhodococcus for the degradation of PCBs has become increasingly important to researchers, as they search for a method to degrade the biologically toxic compounds. Additionally, the ability of Rhodococcus to be used in bioremediaion may be essential in decontaminating polluted land and waterways throughout the United States.

Acessado em: http://microbewiki.kenyon.edu/index.php/Rhodococcus 10/10/11

sexta-feira, 5 de agosto de 2011

Ewingella americana

IntroductionEwingella americana is a gram negative rod, and the only species in the genus Ewingella. It was first identified and characterized in 1983. Ewingella is in the family Enterobacteriaceae. The organism is rarely reported as a human pathogen, though it has been isolated from a variety of clinical specimens including wound, sputum, urine, stool, blood, conjunctiva and peritoneal dialysate.[1] The bacterium is named in honor of William H. Ewing, an American biologist who contributed to modern taxonomy.

[edit] EpidemiologyRespiratory tract infections following retainment in intensive care units has been observed in several instances. Vascular bypass surgery is a reported risk factor for colonization.[2][3] Debate currently exists as to this organism's predilection for immunocompromised patients.[4]

[edit] Pathophysiology and BiochemistryE. americana is an organism with simple nutritional needs that can survive in water and citrate solution and preferentially grows at 4°C. Domestic sources of water including air conditioning units, ice baths and wound irrigation systems have been cited as sources of infection.[5]

[edit] References1.^ Nam-Hee Ryoo, Jung-Sook Ha, Dong-Seok Jeon, Jae-Ryong Kim, Hyun-Chul Kim. (2005). "A Case of Pneumonia Caused by Ewingella americana in a Patient with Chronic Renal Failure.". J Korean Med Sci 20: 143–5. doi:10.3346/jkms.2005.20.1.143. ISSN 1011-8934. PMC 2808562. PMID 15716620.
2.^ Bear, N., K. P. Klugman, L. Tobiansky, and H. J. Koornhof. (1986). "Wound colonization by Ewingella americana.". J. Clin. Microbiol. 23 (3): 650–651. PMC 268717. PMID 3958154.
3.^ Devreese, K., G. Claeys, and G. Verschraegen. (1992). "Septicemia with Ewingella americana.". J. Clin. Microbiol. 30 (10): 2746–2747. PMC 270514. PMID 1400980.
4.^ Heizmann, W. R., and R. Michel. (1991). "Isolation of Ewingella americana from a patient with conjunctivitis.". Eur. J. Clin. Microbiol. Infect. Dis. 10 (11): 957–959. PMID 1794367.
5.^ Farmer, J. J., III, B. R. Davis, F. W. Hickman-Brenner, A. Mc-Whorther, G. P. Huntley-Carter, M. A. Asbury, C. Riddle, H. J. Wathern-Grady, C. Elias, G. R. Fanning, A. G. Steigerwalt, C. M. O’Hara, G. K. Morris, P. B. Smith, and D. J. Brenner. (1985). "Biochemical identification of new species and biogroups of Enterobacteriaceae isolated from clinical specimens.". J. Clin. Microbiol. 21 (1): 46–76. PMC 271578. PMID 3881471.
Retrieved from "http://en.wikipedia.org/wiki/Ewingella_americana" Acessado em 05/08/11

sexta-feira, 29 de julho de 2011

Bacillus

The Genus Bacillus (page 4)

(This chapter has 6 pages)

© 2011 Kenneth Todar, PhD


Genetics of Bacillus

The discovery of transformation in a strain of Bacillus subtilis in 1958, focused attention on the genetics of the bacterium. This is one of relatively few bacteria in which competence for DNA uptake has been found to occur as a natural part of the bacterium's life cycle. Subsequently, generalized and specialized transduction were observed in B. subtilis, and knowledge of the genetics and chromosomal organization of the bacterium quickly mounted to become second only to that of the enteric bacteria. Furthermore, the identification of numerous genes affecting sporulation in B. subtilis has provided a means for analyzing the complex developmental program of sporulation.

Bacteriophages capable of mediating generalized transduction have also been reported in other species of Bacillus, including B. cereus, B. megaterium, B. thuringiensis, B. anthracis, and in Geobacillus stearothermophilus.

Conjugative plasmids are plasmids capable of bringing about their own transfer from one bacterium to another. They have been described in several species of Bacillus. The capacity to produce the insecticidal delta toxin crystal protein in B. thuringiensis is encoded in large plasmids. These plasmids can be transferred to plasmid-deficient strains of B. thuringiensis, as well as to B. cereus, to yield recipients that produce crystal protein. B. thuringiensis transfers the pXO11 and pXO12 plasmids to B. anthracis and to B. cereus. The recipients, in turn, become effective donors, and in the case of those inheriting pXO12, also acquire the ability to produce parasporal crystals. Strains of B. anthracis that acquire plasmid pXO12 can subsequently mobilize and transfer nonconjugative plasmids present in the same cell. The B. anthracis toxin plasmid, pXO1, and the capsule plasmid, pXO2, can be transferred to B. anthracis and B. cereus recipients lacking these plasmids.

The large B. anthracis plasmids are apparently transferred by a process called conduction. This involves formation of cointegrative molecules in the donor, and resolution of the cointegrates into pXO12 and the respective B. anthracis plasmid in the recipient. Cell-to-cell contact is necessary for plasmid transfer and is resistant to DNase, but little is known about the mechanisms or conjugative structures that may be involved. None of the conjugative plasmids have been found to mobilize and transfer chromosomal markers as is observed with the F plasmid of E. coli.

In addition to the naturally occurring transmissible plasmids of Bacillus, a conjugative transposon (Tn925) has been identified, which transfers from Enterococcus faecalis to B. subtilis.

Our understanding of the Bacillus genome, and their means of DNA transfer, has led to its manipulation. So far, this has resulted in numerous medical, agricultural and industrial achievements, involving the use of the organism or its products.


This e.m. image of a spore-forming Bacillus (also at the top of page 1) is that of B. megaterium which has been cloned with the Bt gene and is expressing Bt in the form of the bipyramidal "parasporal" crystal adjacent to the spore.Bt is an insecticidal protein produced by Bacillus thuringiensis.

Ecology

Due to the resistance of their endospores to environmental stress, as well as their long-term survival under adverse conditions, most aerobic sporeformers are ubiquitous and can be isolated from a wide variety of sources. Hence, the occurrence of sporeforming bacteria in a certain environment is not necessarily an indication of habitat. However, it is generally accepted that the primary habitat of the aerobic endospore-forming bacilli is the soil. The great Russian microbiologist, Winogradsky, considered them as "normal flora" of the soil.

In the soil environment the bacteria become metabolically-active when suitable substrates for their growth are available, and presumably they form spores when their nutrients become exhausted. This is a strategy used by other microbes in the soil habitat, including the filamentous fungi and the actinomycetes, which also predominate in the aerobic soil habitat. It is probably not a coincidence, rather an example of convergent evolution, that these three dissimilar groups of microbes live in the soil, form resting structures (spores), and produce antibiotics in association with their sporulation processes.

Since many endospore forming species can effectively degrade a series of biopolymers (proteins, starch, pectin, etc.), they are assumed to play a significant role in the biological cycles of carbon and nitrogen.

From soil, by direct contact or air-borne dust, endospores can contaminate just about anything that is not maintained in a sterile environment. They may play a biodegradative role in whatever they contaminate, and thereby they may be agents of unwanted decomposition and decay. Several Bacillus species are especially important as food spoilage organisms.

Ecophysiological groups

Generally, standard bacteriological criteria do not adequately distinguish the aerobic sporeforming bacteria for discussion or positive identification. An artificial, but convenient, way to organize aerobic spore-formers for this purpose is to place them into ecophysiological groups, such as nitrogen-fixers, denitrifiers, insect pathogens, animal pathogens, thermophiles, antibiotic producers, and so on. Such an approach also allows some speculation concerning the natural history, diversity, and ecology of this important group of bacteria.

Acidophiles: include Acyclobacillus acidocalderius, Bacillus coagulans, and Paenibacillus polymyxa.

Alkaliphiles: B. alcalophilus and Sporosarcina pasteurii. The optimum pH is 8, and some strains grow at pH 11.

Halophiles: Virgibacillus pantothenticus, Sporosarcina pasteurii. Some strains grow in 10 % NaCl.

Psychrophiles or psychrotrophs: Sporosarcina globisporus, Bacillus insolitus, Marinibacillus marinus, Paenibacillus macquariensis, Bacillus megaterium, Paenibacillus polymyxa. Two species will grow and form spores at 0oC.

Thermophiles: include Acyclobacillus acidocalderius, Bacillus schlegelii, and Geobacillus stearothermophilus. Acidophiles and Lithoautotrophs are found in this group, too. The upper temperature limit is 65oC.

Denitrifiers: include Bacillus azotoformans, Bacillus cereus, Brevibacillus laterosporus, Bacillus licheniformis, Sporosarcina pasteurii, Geobacillus stearothermophilus (over half the type species reduce NO3 to NO2). Although Bacillus species are common in agricultural soils, and they are attributed to participate in wasteful denitrification (conversion of the farmer's expensive NO3 fertilizers to volatile N2O or N2) their exact role in the economy of this processes has not been clarified. A related process conducted by some Bacillus species, called dissimilatory nitrate reduction, reduces NO3 to ammonia (NH3), but this is not considered denitrification.

Nitrogen-fixers: Paenibacillus macerans and Paenibacillus polymyxa. Paenibacillus macerans is a fairly prominent bacterium in soil and in decaying vegetable material. The bacteria only fix nitrogen under anaerobic conditions because they do not have a mechanism for protection of their nitrogenase enzyme from the damaging effects of O2. In the same way as the role of the bacilli in denitrification and nitrification, their overall contribution to non symbiotic global nitrogen fixation is not known.

Antibiotic Producers: antibiotics produced by the aerobic sporeformers are often, but not always, polypeptides. Known antibiotic producers are Brevibacillus brevis (e.g. gramicidin, tyrothricin), Bacillus cereus (e.g. cerexin, zwittermicin), Bacillus circulans (e.g. circulin), Brevibacillus laterosporus (e.g. laterosporin), Bacillus licheniformis (e.g. bacitracin), Paenibacillus polymyxa (e.g. polymyxin, colistin), Bacillus pumilus (e.g. pumulin) and Bacillus subtilis (e.g. polymyxin, difficidin, subtilin, mycobacillin).

Bacillus antibiotics share a full range of antimicrobial activity: bacitracin, pumulin, laterosporin, gramicidin and tyrocidin are effective against Gram-positive bacteria; colistin and polymyxin are anti-Gram-negative; difficidin is broad spectrum; and mycobacillin and zwittermicin are anti-fungal.

As in the case of the actinomycetes, antibiotic production in the bacilli is accompanied by cessation of vegetative growth and spore formation. This has led to the idea that the ecological role of antibiotics may not rest with competition between species, but with the regulation of sporulation and/or the maintenance of dormancy.

Pathogens of Insects: Paenibacillus larvae, Paenibacillus lentimorbus and Paenibacillus popilliae are invasive pathogens. Bacillus thuringiensis forms a parasporal crystal that is toxic to Lepidoptera.

P. larvae, P. lentimorbus and P. popilliae are a related cluster of species, being insect pathogens with swollen sporangia and typically catalase-negative. They also are unable to grow in nutrient broth, probably because it is insufficient in thiamin, which they need as a growth factor. Yeast extract (15g/l) must be added to their media for growth. Also, P. lentimorbus and P. popilliae are quite similar in their biochemical properties, virulence and host range. They sometimes occur in coinfections.

P. larvae is the causative agent of American foulbrood of honeybees, which is the most widespread and persistent of the honeybee brood diseases. The organism can be isolated repeatedly from infected brood and honeycomb, usually in a pure culture. It has been noted on many occasions that the natural habitat of the bacterium is remarkably free of contaminants. Presumably, the bacterium can be isolated from soil around the hives of infected bees, but it has not been isolated from other sources. This is indicative of a very close and specific type of host-parasite interaction between the bacterium and the honeybee.

P. popilliae is the cause of the most widespread of two milky diseases of the Japanese beetle, Popillia japonica. Their spores, in a swollen sporangium, are frequently accompanied by a parasporal crystal. Interestingly, the bacterium sporulates with ease in the hemolymph of the infected insect, but it will not form mature spores in most artificial media. Special media have been designed that induce P. popilliae and P. lentimorbus to form mature spores. The prospect that P. popilliae, together with P. lentimorbus, might be used to control or eliminate the Japanese beetle and the European chafer (Amphimallon majalis) has drawn attention to these bacteria. P. popilliae is encountered in naturally-infected grubs far more frequently than P. lentimorbus, which also causes milky disease.

P. lentimorbus is similar in most ways to P. popilliae. The most obvious difference is that P. lentimorbus does not form a parasporal body. The bacteria also differ morphologically and culturally. P. lentimorbus likewise causes one of two milky diseases in the Japanese beetle. The bacterium can only be isolated from the hemolymph of scarabaeid beetles, although it most certainly exists in soil inhabited with infected larvae.

The principal interest in P. lentimorbus arises from its ability to cause disease of Japanese beetle and European chafer larvae, which together cause millions of dollars in damage each year to a variety of plants. P. lentimorbus is more widespread than P. popilliae, which also causes milky disease in the same hosts. The reason the infections are called "milky disease" is that as the disease develops, the larvae become milky in appearance. This is caused by the prolific production of spores in the insect hemolymph.


Spores of the the insect pathogens seen by phase microscopy. U.S. Dept. of Agriculture. A. Paenibacillus larvae spores from a comb infected with American foulbrood; B. Paenibacillus lentimorbus spores from hemolymph of infected Japanese beetle larvae; C. Spores of Paenibacillus popilliae from hemolymph of infected Japanese beetle larvae.

Bacillus thuringiensis is a variety of B. cereus and is therefore considered in the B. cereus-B. anthracis-B. thuringiensis group. B thuringiensis is distinguished from B. cereus or B. anthracis by its pathogenicity for lepidopteran insects and by production of an intracellular parasporal crystal in association with spore formation. The bacteria and protein crystals are marketed as "Bt" insecticide, which is used for the biological control of certain garden and crop pests.

REF: http://www.textbookofbacteriology.net/Bacillus_4.html. Acessado: 29/07/11

Brevibacillus laterosporus




The pathogenicity potential of Brevibacillus laterosporus against insects of various orders has been demonstrated and the results of recent research raise the possibility that novel strains and toxins against new insect targets may be isolated

REF:http://www.sciencedirect.com/science/article/pii/S1049964407001636 Acessado em 29/07/11

In order to explore new natural antimicrobial substance,we purified a kind of antimicrobial substance from a strain of Brevibacillus laterosporus

REF:http://en.cnki.com.cn/Article_en/CJFDTOTAL-CULT201002019.htm aCESSADO EM 27/07/11


Brevibacillus laterosporus comb. nov. (20), previously classified as Bacillus laterosporus (Laubach 1916b), is an aerobic spore-forming bacterium that can also demonstrate pathogenicity to insects


REF: http://aem.asm.org/cgi/content/full/65/11/5182 acESSADO EM 29/07/11


Brevibacillus laterosporus is an aerobic spore-forming bacterium with the ability to produce canoe-shaped lamellar parasporal inclusions adjacent to spores

REF: http://www.ncbi.nlm.nih.gov/pubmed/15950127 aCESSADO EM 29/07/11

Thirty-three strains of Brevibacillus laterosporus, including three novel strains isolated from Brazilian soil samples.

REF:http://aem.asm.org/cgi/content/abstract/70/11/6657 ACessado em: 29/07/11

sexta-feira, 20 de maio de 2011

Micrococcus spp

Micrococcus (mi’ krō kŏk’ Əs) is a genus of bacteria in the Micrococcaceae family. Micrococcus occurs in a wide range of environments, including water, dust, and soil. Micrococci have Gram-positive spherical cells ranging from about 0.5 to 3 micrometers in diameter and are typically appear in tetrads. Micrococcus has a substantial cell wall, which may comprise as much as 50% of the cell mass. The genome of Micrococcus is rich in guanine and cytosine (GC), typically exhibiting 65 to 75% GC-content. Micrococci often carry plasmids (ranging from 1 to 100MDa in size) that provide the organism with useful traits.

Contents [hide]
1 Species
2 Environmental
3 Pathogenesis
4 Industrial uses
5 References


[edit] SpeciesSome species of Micrococcus, such as M. luteus (yellow) and M. roseus (red) produce yellow or pink colonies when grown on mannitol salt agar. Isolates of M. luteus have been found to overproduce riboflavin when grown on toxic organic pollutants like pyridine.[1] Hybridization studies indicate that species within the genus Micrococcus are not closely related, showing as little as 50% sequence homology. This suggests that some Micrococcus species may, on the basis of ribosomal RNA analysis, eventually be re-classified into other microbial genera.

[edit] EnvironmentalMicrococci have been isolated from human skin, animal and dairy products, and beer. They are found in many other places in the environment, including water, dust, and soil. M. luteus on human skin transforms compounds in sweat into compounds with an unpleasant odor. Micrococci can grow well in environments with little water or high salt concentrations. Most are mesophiles; some, like Micrococcus antarcticus (found in Antarctica) are psychrophiles.

Though not a spore former, Micrococcus cells can survive for an extended period of time: unprotected cultures of soil micrococci have been revived after storage in a refrigerator for 10 years.[citation needed] Recent work by Greenblat et al. demonstrate that Micrococcus luteus has survived for at least 34,000 to 170,000 years on the basis of 16S rRNA analysis, and possibly much longer.[2]

[edit] PathogenesisMicrococcus is generally thought to be a saprotrophic or commensal organism, though it can be an opportunistic pathogen, particularly in hosts with compromised immune systems, such as HIV patients.[3] It can be difficult to identify Micrococcus as the cause of an infection, since the organism is a normally present in skin microflora, and the genus is seldom linked to disease. In rare cases, death of immunocompromised patients has occurred from pulmonary infections caused by Micrococcus. Micrococci may be involved in other infections, including recurrent bacteremia, septic shock, septic arthritis, endocarditis, meningitis, and cavitating pneumonia (immunosuppressed patients).

[edit] Industrial usesMicrococci, like many other representatives of the Actinobacteria, can be catabolically versatile, with the ability to utilize a wide range of unusual substrates, such as pyridine, herbicides, chlorinated biphenyls, and oil.[4][5] They are likely involved in detoxification or biodegradation of many other environmental pollutants.[6] Other Micrococcus isolates produce various useful products, such as long-chain (C21-C34) aliphatic hydrocarbons for lubricating oils.

[edit] References1.^ Sims GK, Sommers LE, Konopka A (1986). "Degradation of Pyridine by Micrococcus luteus Isolated from Soil". Appl Environ Microbiol 51 (5): 963–968. PMC 238995. PMID 16347070. http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=238995.
2.^ Greenblat, C.L., Baum, J., Klein, B.Y., Nachshon, S., Koltunov, V., Cano, R.J., (2004). "Micrococcus luteus – Survival in Amber". Microbial Ecology 48 (1): 120–127. doi:10.1007/s00248-003-2016-5. PMID 15164240.
3.^ Smith K, Neafie R, Yeager J, Skelton H (1999). "Micrococcus folliculitis in HIV-1 disease". Br J Dermatol 141 (3): 558–61. doi:10.1046/j.1365-2133.1999.03060.x. PMID 10583069.
4.^ Doddamani H, Ninnekar H (2001). "Biodegradation of carbaryl by a Micrococcus species". Curr Microbiol 43 (1): 69–73. doi:10.1007/s002840010262. PMID 11375667.
5.^ Sims GK, O'loughlin EJ (1992). "Riboflavin Production during Growth of Micrococcus luteus on Pyridine". Appl Environ Microbiol 58 (10): 3423–3425. PMC 183117. PMID 16348793. http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=183117.
6.^ Zhuang W, Tay J, Maszenan A, Krumholz L, Tay S (2003). "Importance of Gram-positive naphthalene-degrading bacteria in oil-contaminated tropical marine sediments". Lett Appl Microbiol 36 (4): 251–7. doi:10.1046/j.1472-765X.2003.01297.x. PMID 12641721.


ref http://en.wikipedia.org/wiki/Micrococcus Acessado em 20/05/11

Regulatory Agencies





  1. http://www.bacteriamuseum.org/cms/Bacterial-Species-Cabinet/




  2. http://www.fda.gov/




  3. http://dg3.eudra.org/




  4. http://www.emea.eu.int/




  5. http://heads.medagencies.org/




  6. http://www.mhra.gov.uk/




  7. http://heads.medagencies.org/germany.html




  8. www. infarmed.pt/index2.html




  9. http://agmed.sante.gouv.fr/




  10. www.msc.es/agemed




  11. http://www.afigp.fgov.be/




  12. http://www.legemiddelverket.no/




  13. www.mpa.se/eng/index.html




  14. www.nam.fi/english/index.html




  15. www.ministerosalute.it/medicinali




  16. http://ec.europa.eu/health/documents/eudralex/vol-4/index_en.htm


  17. http://www.gmp-compliance.org/eca_link_navigator.html

  18. www.cbg-med-nl

  19. Australia - Therapeutic Goods Administration (TGA) - www.tga.gov.au

  20. Bulgaria - Bulgarian Drug Agency - www.bda.bg/web_engl/main.htm

  21. Canada - Therapeutic Products Diretorate (TPD) - www.hc-sc.gc.ca/hpb-dgps/therapeutic/htmleng

  22. Chile - Chile Regulatory Agency - www.minsal.cl

  23. Russia - Czech Republic - www.sukl.cz/enindex.htm

  24. Denmanrk - The Danish Medicines Agency - www.laegemiddelstyrelsen.dk/index_en.htm

  25. Estonia - State Agency of medicines - www.dam.ee

  26. Greece - EOD - www.eof.gr

  27. Hong Kong - Hong Kong Department od Health Welfare and Food - www.fwfb.gov.hk/eindex.html

  28. India - Ministry of health and family welfare - http://mohfw.nic.in

  29. Ireland - Irish Medicine Board - www.imb.ie

  30. Japan - Ministry of Health, Labour and Welfare - (MHLW) - www.mhlw.go.jp/english

  31. Russia - Ministry of Health of the Russian Federation - www.minsalud.gov.com

  32. Switzerland - Swiss Medic - www.swissmedic.ch


segunda-feira, 16 de maio de 2011

Aspergillus niger

Aspergillus niger is a fungus and one of the most common species of the genus Aspergillus. It causes a disease called black mold on certain fruits and vegetables such as grapes, onions, and peanuts, and is a common contaminant of food. It is ubiquitous in soil and is commonly reported from indoor environments, where its black colonies can be confused with those of Stachybotrys (species of which have also been called "black mould").[1]

Some strains of A. niger have been reported to produce potent mycotoxins called ochratoxins,[2] but other sources disagree, claiming this report is based upon misidentification of the fungal species. Recent evidence suggests some true A. niger strains do produce ochratoxin A.[1][3]

Human and animal diseaseA. niger is less likely to cause human disease than some other Aspergillus species, but, if large amounts of spores are inhaled, a serious lung disease, aspergillosis can occur. Aspergillosis is, in particular, frequent among horticultural workers that inhale peat dust, which can be rich in Aspergillus spores. It has been found on the walls of ancient Egyptian tombs and can be inhaled when the area is disturbed.[citation needed] A. niger is one of the most common causes of otomycosis (fungal ear infections), which can cause pain, temporary hearing loss, and, in severe cases, damage to the ear canal and tympanic membrane.

REF:http://en.wikipedia.org/wiki/Aspergillus_niger ACessado em 16/05/11

Aspergillus niger
On Czapek dox agar, colonies consist of a compact white or yellow basal felt covered by a dense layer of dark-brown to black conidial heads. Conidial heads are large (up to 3 mm x 15-20 um in diameter), globose, dark brown, becoming radiate and tending to split into several loose columns with age. Conidiophores are smooth-walled, hyaline or turning dark towards the vesicle. Conidial heads are biseriate with the phialides borne on brown, often septate metulae. Conidia are globose to subglobose (3.5-5.0 um in diameter), dark brown to black and rough-walled. RG-1 organism.

Clinical significance:
Aspergillus niger is one of the most common and easily identifiable species of the genus Aspergillus, with its white to yellow mat later bearing black conidia. This is the third most common species associated with invasive pulmonary aspergillosis. It is also often a causative agent of aspergilloma and is the most frequently encountered agent of otomycosis. A. niger may also be a common laboratory contaminant.

REF: http://www.mycology.adelaide.edu.au/Fungal_Descriptions/Hyphomycetes_(hyaline)/Aspergillus/niger.html Acessado em 16/05/11

Bacillus sp

Bacillus is a genus of Gram-positive rod-shaped bacteria and a member of the division Firmicutes. Bacillus species can be obligate aerobes or facultative anaerobes, and test positive for the enzyme catalase.[1] Ubiquitous in nature, Bacillus includes both free-living and pathogenic species. Under stressful environmental conditions, the cells produce oval endospores that can stay dormant for extended periods. These characteristics originally defined the genus, but not all such species are closely related, and many have been moved to other genera.[2]

^ Madigan M; Martinko J (editors). (2005). Brock Biology of Microorganisms (11th ed.). Prentice Hall. ISBN 0-13-144329-1.

ref:

Bacilli are rod-shaped, Gram-positive, sporulating, aerobes or facultative anaerobes. Most bacilli are saprophytes. Each bacterium creates only one spore, which is resistant to heat, cold, radiation, desiccation, and disinfectants. Bacilli exhibit an array of physiologic abilities that allow them to live in a wide range of habitats, including many extreme habitats such as desert sands, hot springs, and Arctic soils. Species in the genus Bacillus can be thermophilic, psychrophilic, acidophilic, alkaliphilic, halotolerant, or halophilic and are capable at growing at pH values, temperatures, and salt concentrations where few other organisms can survive
Ecology
Due to the metabolic diversity in the genus Bacillus, bacilli are able to colonize a variety of habitats ranging from soil and insects to humans. Bacillus thuringiensis parasitizes insects, and is commercially used for pest control. Although the most well known of the bacilli are the pathogenic species, most Bacillus are saprophytes that make their living off of decaying matter. Still others, namely Bacillus subtilis, inhabit the rhizosphere, which is the interface between plant roots and the surrounding soil. The plants roots and associated biofilm can have a significant effect on the chemistry of the soil, creating a unique environment.


REFhttp://microbewiki.kenyon.edu/index.php/Bacillus Acessado em 16/05/11

segunda-feira, 9 de maio de 2011

Ralstonia pickettii

Ralstonia pickettii
From MicrobeWiki, the student-edited microbiology resource
Classification
Bacteria; Proteobacteria; Beta Proteobacteria; Burkholderiales; Ralstoniaceae
Ralstonia Picketti
NCBI: Taxonomy

Ralstonia Pickettii
Synonyms: Burkholderia picketti, Burkholderia solanacearum, Alcaligenes eutrophus
Strains: 12J,12D
Description and Significance
Ralstonia pickettii is a gram-negative, rod shaped beta proteobacteria found in moist environments such as soils, river and lakes [2]. It has also been identified in biofilms in plastic water pipes [1]. It is an olgiotrophic organism, making it capable of surviving in areas with a very low concentration of nutrients [1]. Several strains have shown an ability to survive in environments highly contaminated with metals such as Copper (Cu), Nickel (Ni), Iron (Fe) and Zinc (Zn). The ability to persist in these harsh conditions makes R. picketti a unique candidate for bioremediation. In a study done by Fett et al., R. pickettii was shown to be resistant to environments with up to 1200 µg/mL of Cu, surviving by using phosphates to sequester the metal [3].
Genome Structure
There are two separate strains of Ralstonia pickettii, 12 D and 12 J of sizes 3.5 Mb and 3.0 Mb respectively [7]. While their rRNA sequence is indentical, there are significant differences in their genomic structures [7]. The 12 D strain contains two circular chromosomes 3,647,724bp and 1,323,321 bp in size; as well as three circular plasmids 389,779 bp, 273,136 bp and 51,398 bp in size [8]. The 12 J strand also consists of two circular chromosomes 3,942,557 bp and 1,302,228 bp in size; but has only one circular plasmid that is 80,934 bp in size [9].
Cell Structure and Metabolism
Ralstonia pickettii is a gram-negative rod shaped bacteria. These bacteria are culturable in the lab and often form dense dark white colonies. It is strictly an aerobe and is not capable of fermentive respiration [4]. As a chemoheterotroph it depends on an outside carbon source for cell growth, meaning that in remediation, biostimulation can result in increased results of disposing of the pollutant [1]. And, as a siderophore, R. pickettii thrives in environments containing high levels of Iron, and is capable of sollublizing Fe3+ [5]. R. pickettii can also break down several aromatic hydrocarbons or volatile organic compounds (VOC’s) such as cresol (C7H8O), phenol (C6H5OH) and toluene (C7H8). These chemical compounds are commonly found in household products including antiseptics, germicides and cleaners. They are hazardous to the environment, and often accumulate to toxic levels in soil and groundwater [1]. R. pickettii is able to exploit this resource by using the hydrocarbons as both a source of carbon and energy. This process is achieved through a series of multi-enzyme pathways, including the Tbu pathway which converts aromatic hydrocarbons to catechols [1]. Another distinguishing feature of this bacteria is that is can metabolize aromatic hydrocarbons in hypoxic environments. Unlike other toluene metabolizing bacteria, R. pickettii can break down toluene even when oxygen levels are only 25% of air-saturated water [1].
Pathogenesis
Ralstonia pickettii pathology does not follow an easy definition; although no fully healthy human has ever become ill from R. pickettii, the bacteria has seriously affected humans with poor health. Several hospitals have reported outbreaks - in particular, patients with cystic fibrosis and Crohn’s Disease have been shown to be infected R. pickettii [2]. Of the 55 reported cases of infection by R. pickettii, the majority are due to contaminated solutions such as water, saline and sterile drugs [6]. These solutions are usually contaminated when the product is manufactured, due to the fact that R. pickettii has the ability to pass through 0.45 and 0.2mm filters that are used to stearilize medicinal products [6]. As a result when given as a drip solution, intravenously, or for endotracheal suctioning these contaminated solutions often lead infection in both the blood stream and the respiratory system [6].
Ecology and Biotechnology
The ability of Ralstonia pickettii to withstand high metal concentrations led to multiple test to determine if the bacteria could be used for bioremediation. The fact that R. pickettii grows easily in so many environments and does act as a pathogen makes it a great option. In vitro tests have shown that through biostimulation, R. pickettii was capable of degrading such contaminates as TCE and aromatic hydrocarbons [1]. The PKO1 strain has a future to be a great biodegrader as it was capable of remediating several pollutants [1]. The LD1 strain showed the ability to degrade chlorinated phenolic compounds [1]. These CPC’s were frequently used, as pesticides are an extremely common contaminate [1].
References
1. Adley C, Pembroke J, Ryan M. (Feb 2007) Ralstonia pickettii in environmental biotechnology potential and applications. Journal of Applied Microbiolgy. Vol 103. pp 754-764.
2. Coenye T, De Vos P, Goris J, Vandamme P. (2003). Classification of Ralstonia pickettii-like isolates from the environment and clinical samples as Ralstonia insidiosa. International Journal of Systematic and Evolutionary Microbiology. Vol 53. 2003 pp 1075-1080
3. Fett J, Konstantinidis K, Isaacs N, Long D, Marsh T. (Feb 2003).Microbial Diversity and Resistance to Copper in Metal-Contaminated Lake Sediment. Microbial Ecology. Vol 45. Feb 2003. pp 191-202
4. Buckner D, Colona P. (Jul 1997) Nomenclature for Aerobic and Facultative Bacteria. Clinical Infectious Diseases. Vol 25. pp 1-10
5. Biebl M, Bonatti H, Eller M, Fille M, Hoeller E, Lass-Floerl C, Stelzmueller I, Weiss G. (2006) Ralstonia pickettii-innocent bystander or a potential threat?. Clinical Microbial Infect. Vol 12. pp 99-101
6. Ryan, M. P., J. T. Pembroke, and C. C. Adley. (2006) Ralstonia Pickettii: a Persistent Gram-negative Nosocomial Infectious Organism." Journal of Hospital Infection Vol 62. March 2006. pp278-84.
7. "Ralstonia Pickettii." JGI Genome Portal - Home. Web. 25 Apr. 2010. .
8. "HAMAP: Ralstonia Pickettii (strain 12D) Complete Proteome." ExPASy Proteomics Server. Swiss Institute for Bioinformatics. Web. 25 Apr. 2010. .
9. "HAMAP: Ralstonia Pickettii (strain 12J) Complete Proteome." ExPASy Proteomics Server. Swiss Institute for Bioinformatics. Web. 25 Apr. 2010. .
Author
Page authored by Jeff Eggleston and Sarah Dionne, students of Prof. Jay Lennon at Michigan State University.

REF: http://microbewiki.kenyon.edu/index.php/Ralstonia_pickettii Acessado em 09/05/2011

quarta-feira, 20 de abril de 2011

Cryptococcus lauretii - port

MORFOLOGIA: levedura, suas células tem caraerísticas esféricas e alongadas com ou sem blastoconídios, com capacdade limitada de formar hifas com clamidiosporos.

PATOGIA: raros casos de infecção pulmonar ou cutânea tem sido reportado. Também pode ser ocasionalmente recuperado como saprofitas de pele.


HABITAT:
C. laurentii é a levedura mais freqüentemente encontradas na tundra, da Antártida e os solos de pradaria, bem como nas superficies de folhas de muitos ecossistemas. As matérias fecais de aves saudáveis ​​tem sido apontada como um importante repositório de fungos criptocócica.


http://www.mycology.adelaide.edu.au/Fungal_Descriptions/Yeasts/Cryptococcus/C_laurentii.html 20/04/11


ver: http://ddr.nal.usda.gov/bitstream/10113/32139/1/CAIN739173668.pdf

Cryptococcus laurentii Submitted by amh10 on 7 February, 2008 - 01:11 MRCPath Part2MycologyTraining Cryptococcus laurentii is an extremely rare human pathogen. This fungus was previously considered saprophytic and nonpathogenic to humans, but it has been isolated as the etiologic agent of skin infection, keratitis, endophthalmitis, lung abscess, peritonitis,meningitis and fungaemia. Ecology C. laurentii is the most frequently encountered yeast in tundra, Antarctic and prairie soils as well as the phyllosphere of numerous ecosystems. The faecal matter of healthy birds has been identified as an important repository for cryptococcal fungi. Although the related species C. neoformans has been identified as an important human pathogen, infections with C. laurentii occur almost exclusively in immuno-compromised individuals and rarely result in clinically significant outcomes. C. laurentii is psychrophillic and grows poorly above 30°C temperatures. While optimal growth temperatures of 15°C have been reported for this species, it is cryotolerant and can be successfully cultured at near freezing conditions. C. laurentii has been described as a facultative alkaliphile. On Sabouraud's dextrose agar colonies are cream colored, often becoming a deeper orange-yellow with age, with a smooth mucoid texture. Microscopic morphology : Spherical and elongated budding yeast-like cells or blastoconidia, 2.0-5.5 x 3.0-7.0 μm in size. No pseudohyphae present. India Ink Preparation: Positive - narrow but distinct capsules surrounding the yeast cells are present. Dalmau Plate Culture on Cornmeal and Tween 80 Agar: Budding yeast cells only. No pseudohyphae present. Physiological Tests: Germ Tube test is Negative Hydrolysis of Urea is Positive Growth on Cycloheximide medium is Variable Growth at 37C is Negative (weak growth in some strains) Fermentation Reactions: Where fermentation means the production of gas and is independent of pH changes. Negative: Glucose; Sucrose; Lactose; Galactose; Maltose; Trehalose. Susceptibility: •Can be fluconazole resistant •Usually treated with amphotericin REF: http://microblog.me.uk/332 Accessed: 20/04/11 Cryptococcus laurentii On Sabouraud's dextrose agar colonies are cream colored, often becoming a deeper orange-yellow with age, with a smooth mucoid texture. Microscopic morphology : Spherical and elongated budding yeast-like cells or blastoconidia, 2.0-5.5 x 3.0-7.0 um in size. No pseudohyphae present India Ink Preparation: Positive - narrow but distinct capsules surrounding the yeast cells are present. Dalmau Plate Culture on Cornmeal and Tween 80 Agar: Budding yeast cells only. No pseudohyphae present. Physiological Tests: Germ Tube test is Negative Hydrolysis of Urea is Positive Growth on Cycloheximide medium is Variable Growth at 37C is Negative (weak growth in some strains) Fermentation Reactions: Where fermentation means the production of gas and is independent of pH changes. Negative: Glucose; Sucrose; Lactose; Galactose; Maltose; Trehalose. Assimilation Tests: Positive: Glucose; Glucose; Galactose; Maltose; Sucrose; Trehalose; D-Xylose (weak); Melezitose; Lactose; Raffinose; Cellobiose; Melibiose; Inositol (delayed); L-Rhamnose; D-Arabinose; L-Arabinose; D-Mannitol; Ribitol; D-Ribose (delayed); Galactitol; Salicin. Variable: Erythritol; Soluble Starch; D-Glucitol; Glycerol; Citric acid; DL-Lactic acid; Succinic acid. Negative: Potassium nitrate; L-Sorbose (some positive). Clinical significance: Cryptococcus laurentii has been reported as a rare cause of pulmonary and cutaneous infection and CAPD associated peritonitis in humans. It may also be occasionally recovered as a saprophyte from skin. REF: http://www.mycology.adelaide.edu.au/Fungal_Descriptions/Yeasts/Cryptococcus/C_laurentii.html Accessed: 20/04/11 Look at this site: http://labmed.ucsf.edu/education/residency/fung_morph/fungal_site/yeastpage.html

quarta-feira, 13 de abril de 2011

Staphylococcus xylosus

Staphylococcus xylosus is a species of bacteria belonging to the genus Staphylococcus. It is a Gram-positive bacterium that forms clusters of cells. Like most staphylococcal species, it is coagulase-negative and exists as a commensal on the skin of humans and animals and in the environment.

It appears to be far more common in animals than in humans. S. xylosus has very occasionally been identified as a cause of human infection, but in some cases it may have been misidentified.

IdentificationS. xylosus is normally sensitive to fleroxacin, methicillin, penicillin, teicoplanin, tetracycline and resistant erythromycin and novobiocin. It is highly active biochemically, producing acid from a wide variety of carbohydrates.

Acid and gas are produced from D-(+)-galactose, D-(+)-mannose, D-(+)-mannitol, maltose and lactose. Caseinolytic and gelatinase activities are normally present.

It normally produces slime but not capsules. This ability is lost upon subculture. Cell wall peptidoglycan similar to L-Lys-Gly3-5. L-Ser0.6-1.5 type found in predominately human species

Clinical importanceStaphylococcus xylosus has been associated with the following conditions:

Nasal dermatitis in gerbils
Pyelonephritis in humans
Avian staphylococcosis
Bovine intermammary infection
It is also found

In milk, cheese & sausages
On skin of many animals

REF: http://en.wikipedia.org/wiki/Staphylococcus_xylosus Acesses: 13/04/11


Staphylococcus xylosus is a Gram positive bacterium with a low G + C content. It belongs to the coagulase-negative group of staphylococci. It is a commensal bacterium of the skin which is of major interest for several reasons.
This bacterium is used as a fermenting agent in the production of meat (sausage) and milk (cheese) products. It contributes to the development of the red color characteristic of sausages through its nitrate reductase activity (photo 1) and to the orange color on the surface of certain cheeses, since some strains of S. xylosus are pigmented (photo 2).

This bacterium is mentioned as a dominant species in production facilities. Some strains of S. xylosus are capable of colonizing surfaces by forming biofilms (photo 3).
There is a great diversity of strains within this species. As a result of this diversity, certain strains isolated from milk and raw ham produce enterotoxins D, C or E, and as such may present a risk for the consumer. Other strains of S. xylosus are opportunistic pathogens of animals. Strains of S. xylosus, some of which have been isolated in nosocomial infections, have been described as multi-resistant to diverse antibiotics.

The genome of S. xylosus is estimated at 2.8 Mb. The complete sequence of this genome will lead to the establishment of the genetic bases of the specific properties of this species in comparison with the genomes of other staphylococci: S. aureus, S. epidermididis and S. carnosus. It will also make it possible to identify the genetic bases for the adaptation of this bacterium to the agro-alimentary environment, and functions of technologic interest. The stud of the genome of S. xylosus will make it possible to evaluate the innocuousness of the strains used as fermenting agents.

REF: http://www.cns.fr/spip/Staphylococcus-xylosus-commensal.html Access: 13/04/11

Bacterioides

Bacteroides species are anaerobic bacteria that are predominant components of the bacterial florae of mucous membranes[1] and are therefore a common cause of endogenous infections. Bacteroides infections can develop in all body sites, including the CNS, the head, the neck, the chest, the abdomen, the pelvis, the skin, and the soft tissues. Inadequate therapy against these anaerobic bacteria may lead to clinical failure.

Because of their fastidiousness, they are difficult to isolate and are often overlooked. Their isolation requires appropriate methods of collection, transportation, and cultivation of specimens.[2] Treatment is complicated by 3 factors: slow growth, increasing resistance to antimicrobial agents,[3] and the polymicrobial synergistic nature of the infection.[4]

The B fragilis group, a member of the Bacteroidaceae family, includes B fragilis (causes the most clinical infections), Bacteroides distasonis, Bacteroides ovatus, Bacteroides thetaiotaomicron, and Bacteroides vulgatus. These bacteria are resistant to penicillins, mostly through the production of beta-lactamase. They are part of the normal GI florae[1] and predominate in intra-abdominal infections and infections that originate from those florae (eg, perirectal abscesses, decubitus ulcers). Enterotoxigenic B fragilis (ETBF) is also a potential cause of diarrhea.[5]

Pigmented Prevotella, such as Prevotella melaninogenica and Prevotella intermedia (which were previously called the Bacteroides melaninogenicus group), Porphyromonas (eg, Porphyromonas asaccharolytica), and nonpigmented Prevotella (eg, Prevotella oralis, Prevotella oris) are part of the normal oral and vaginal florae and are the predominant AGNB isolated from respiratory tract infections and their complications, including aspiration pneumonia, lung abscess, chronic otitis media, chronic sinusitis, abscesses around the oral cavity, human bites, paronychia, brain abscesses, and osteomyelitis. Prevotella bivia and Prevotella disiens (previously called Bacteroides) are important in obstetric and gynecologic infections

REF: http://emedicine.medscape.com/article/233339-overview Access: 13,apr,2011

Bacteroides Infection
Author: Itzhak Brook, MD, MSc; Chief Editor: Burke A Cunha, MD



Bacteroides is a genus of Gram-negative, bacillus bacteria. Bacteroides species are non-endospore-forming, anaerobes, and may be either motile or non-motile, depending on the species.[1] The DNA base composition is 40-48% GC. Unusual in bacterial organisms, Bacteroides membranes contain sphingolipids. They also contain meso-diaminopimelic acid in their peptidoglycan layer.

Bacteroides are normally mutualistic, making up the most substantial portion of the mammalian gastrointestinal flora,[2] where they play a fundamental role in processing of complex molecules to simpler ones in the host intestine.[3][4][5] As many as 1010-1011 cells per gram of human feces have been reported.[6] They can use simple sugars when available, but the main source of energy is polysaccharides from plant sources.

One of the most important clinically is Bacteroides fragilis.

Bacteroides melaninogenicus has recently been reclassified and split into Prevotella melaninogenica and Prevotella intermedia.[7]

PathogenesisBacteroides species also benefit their host by excluding potential pathogens from colonizing the gut. Some species (B. fragilis, for example) are opportunistic human pathogens, causing infections of the peritoneal cavity, gastrointestinal surgery, and appendicitis via abscess formation, inhibiting phagocytosis, and inactivating beta-lactam antibiotics.[8] Although Bacteroides species are anaerobic, they are aerotolerant and thus can survive in the abdominal cavity.

In general, Bacteroides are resistant to a wide variety of antibiotics — β-lactams, aminoglycosides, and recently many species have acquired resistance to erythromycin and tetracycline. This high level of antibiotic resistance has prompted concerns that Bacteroides species may become a reservoir for resistance in other, more highly-pathogenic bacterial strains.[9] [10]

Microbiological ApplicationsAn alternative fecal indicator organism, Bacteroides, has been suggested because they make up a significant portion of the fecal bacterial population[11], have a high degree of host specificity that reflects differences in the digestive system of the host animal[12], and have a small potential to grow in the environment[13]. Over the past decade, real-time polymerase chain reaction (PCR) methods have been utilized to detect the presence of various microbial pathogens through the amplification of specific DNA sequences without culturing bacteria. One study has measured the amount of Bacteroides by using qPCR to quantify the 16S rRNA genetic marker that is host-specific.[14] This technique allows quantification of genetic markers that are specific to the host of the bacteria and allow detection of recent contamination. A recent report found that temperature plays a major role in the amount of time the bacteria will persist in the environment, the life span increases with colder temperatures
References1.^ Madigan M, Martinko J (editors). (2005). Brock Biology of Microorganisms (11th ed.). Prentice Hall. ISBN 0-13-144329-1.
2.^ Dorland WAN (editor) (2003). Dorland's Illustrated Medical Dictionary (30th ed.). W.B. Saunders. ISBN 0-7216-0146-4.
3.^ Wexler, H. M. (Oct 2007). "Bacteroides: the good, the bad, and the nitty-gritty" (Free full text). Clinical microbiology reviews 20 (4): 593–621. doi:10.1128/CMR.00008-07. ISSN 0893-8512. PMC 2176045. PMID 17934076. http://cmr.asm.org/cgi/pmidlookup?view=long&pmid=17934076. edit
4.^ Xu, J.; Gordon, I. (Sep 2003). "Inaugural Article: Honor thy symbionts" (Free full text). Proceedings of the National Academy of Sciences of the United States of America 100 (18): 10452–10459. doi:10.1073/pnas.1734063100. ISSN 0027-8424. PMC 193582. PMID 12923294. http://www.pnas.org/cgi/pmidlookup?view=long&pmid=12923294. edit
5.^ Xu, J.; Mahowald, A.; Ley, E.; Lozupone, A.; Hamady, M.; Martens, C.; Henrissat, B.; Coutinho, M. et al. (Jul 2007). "Evolution of symbiotic bacteria in the distal human intestine" (Free full text). PLoS biology 5 (7): e156. doi:10.1371/journal.pbio.0050156. ISSN 1544-9173. PMC 1892571. PMID 17579514. http://dx.plos.org/10.1371/journal.pbio.0050156. edit
6.^ Finegold SM, Sutter VL, Mathisen GE (1983). Normal indigenous intestinal flora (pp. 3-31) in Human intestinal microflora in health and disease.. Academic Press. ISBN 0-12-341280-3.
7.^ "Bacteroides Infection: Overview - eMedicine". http://emedicine.medscape.com/article/233339-overview. Retrieved 2008-12-11.
8.^ Ryan KJ, Ray CG (editors) (2004). Sherris Medical Microbiology (4th ed.). McGraw Hill. ISBN 0-8385-8529-9.
9.^ Salyers AA, Gupta A, Wang Y (2004). "Human intestinal bacteria as reservoirs for antibiotic resistance genes". Trends Microbiol 12 (9): 412–6. doi:10.1016/j.tim.2004.07.004. PMID 15337162.
10.^ Löfmark, S.; Jernberg, C.; Jansson, K.; Edlund, C. (Dec 2006). "Clindamycin-induced enrichment and long-term persistence of resistant Bacteroides spp. And resistance genes" (Free full text). The Journal of antimicrobial chemotherapy 58 (6): 1160–1167. doi:10.1093/jac/dkl420. ISSN 0305-7453. PMID 17046967. http://jac.oxfordjournals.org/cgi/pmidlookup?view=long&pmid=17046967. edit
11.^ Madigan M, Martinko J (editors). (2005). Brock Biology of Microorganisms (11th ed.). Prentice Hall. ISBN 0-13-144329-1.
12.^ Bernhard and Field, A.E. and K.G.; Field, KG (2000). "A PCR Assay To Discriminate Human and Ruminant Feces on the Basis of Host Differences in Bacteroides-Prevotella Genes Encoding 16S rRNA". Applied and Environmental Microbiology 66 (10): 4571–4574. doi:http://water.rutgers.edu/Source_Tracking/Bacteroidetes/APCRAssayToDiscriminateHumanandRuminantFecesontheBasisofHostDifferencesinBacteroides.pdf. PMC 92346. PMID 11010920. http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=92346.
13.^ Kreader, C.A. (1998). "Persistence of PCR-Detectable Bacteroides distasonis from Human Feces in River Water". Applied and Environmental Microbiology 64 (10): 4103–4105. doi:http://www.water.rutgers.edu/Source_Tracking/Bacteroidetes/PersistenceofPCR-DetectableBacteroidesdistasonisfromHumanFecesinRiverWater.pdf. PMC 106613. PMID 9758854. http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=106613.
14.^ Layton, A.; McKay, L; Williams, D; Garrett, V; Gentry, R; Sayler, G (2006). "Development of Bacteroides 16S rRNA Gene TaqMan-Based Real-Time PCR Assays for Estimation of Total, Human,and Bovine Fecal Pollution in Water". Applied and Environmental Microbiology 72 (6): 4214–4224. doi:http://aem.asm.org/cgi/content/short/72/6/4214. PMC 1489674. PMID 16751534. http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=1489674.
15.^ Bell, Layton, McKay, Williams, Gentry, Sayler, A., A.C., L., D., R., G.S.; Layton, Alice C.; McKay, Larry; Williams, Dan; Gentry, Randy; Sayler, Gary S. (2009). "Factors Influencing the Persistance of Fecal Bacteroides in Stream Water". J. Environ. Qual. 38 (3): 1224–1232. doi:10.2134/jeq2008.0258. PMID 19398520.

REF: http://en.wikipedia.org/wiki/Bacteroides .Access: 13/apr/2011

terça-feira, 29 de março de 2011

Bacterioides ovatus

Introduction
Background
This article describes infections caused by the Bacteroides fragilis group and other anaerobic gram-negative bacilli (AGNB) that were previously included in the Bacteroides genus but are now included in the Prevotella and Porphyromonas genera. Infections due to AGNB are common, yet the specific identification of AGNB in these infections is difficult.

Bacteroides species are anaerobic bacteria that are predominant components of the bacterial florae of mucous membranes1 and are therefore a common cause of endogenous infections. Bacteroides infections can develop in all body sites, including the CNS, the head, the neck, the chest, the abdomen, the pelvis, the skin, and the soft tissues. Inadequate therapy against these anaerobic bacteria may lead to clinical failure.

Because of their fastidiousness, they are difficult to isolate and are often overlooked. Their isolation requires appropriate methods of collection, transportation, and cultivation of specimens.2 Treatment is complicated by 3 factors: slow growth, increasing resistance to antimicrobial agents,3 and the polymicrobial synergistic nature of the infection.4
The B fragilis group, a member of the Bacteroidaceae family, includes B fragilis (causes the most clinical infections), Bacteroides distasonis, Bacteroides ovatus, Bacteroides thetaiotaomicron, and Bacteroides vulgatus. These bacteria are resistant to penicillins, mostly through the production of beta-lactamase. They are part of the normal GI florae1 and predominate in intra-abdominal infections and infections that originate from those florae (eg, perirectal abscesses, decubitus ulcers). Enterotoxigenic B fragilis (ETBF) is also a potential cause of diarrhea.5
Pigmented Prevotella, such as Prevotella melaninogenica and Prevotella intermedia (which were previously called the Bacteroides melaninogenicus group), Porphyromonas (eg, Porphyromonas asaccharolytica), and nonpigmented Prevotella (eg, Prevotella oralis, Prevotella oris) are part of the normal oral and vaginal florae and are the predominant AGNB isolated from respiratory tract infections and their complications, including aspiration pneumonia, lung abscess, chronic otitis media, chronic sinusitis, abscesses around the oral cavity, human bites, paronychia, brain abscesses, and osteomyelitis. Prevotella bivia and Prevotella disiens (previously called Bacteroides) are important in obstetric and gynecologic infections.


Pathophysiology
Most infections due to AGNB originate from the endogenous mucosal membrane florae. Knowledge of the common mode of distribution allows for a logical choice of antimicrobial therapy for infections in these sites.

AGNB infections are generally polymicrobial. The number of isolates can reach 5-10 organisms. The type of copathogens depends on the infection site and the circumstances of the infection. Antimicrobial therapy should be directed at all major aerobic and anaerobic pathogens. AGNB promote infection through synergy with their aerobic and anaerobic counterparts and with each other.

An indirect pathogenic role of AGNB is their ability to produce the enzyme beta-lactamase, which allows them to protect themselves and other penicillin-susceptible organisms from the activity of penicillins.

Frequency
United States
The exact frequency of AGNB infection is difficult to calculate because of inappropriate methods of collection, transportation, and cultivation of specimens. AGNB are more commonly found in chronic infections. Their rate of recovery in blood cultures is 2-5% and higher with patients who have predisposing conditions.

International
The frequency of these infections appears to be higher in developing countries, where therapy is often inadequate or delayed.

Mortality/Morbidity
The mortality rate has decreased over the past 3 decades because of early recognition and initiation of proper prophylactic and therapeutic antimicrobial therapies.

Age
AGNB infections can occur in patients of all ages; however, the frequency of head and neck infections is higher in pediatric patients than in other patients.

Clinical
History
AGNB infections occur more often in chronic infections and in association with the predisposing conditions discussed below. However, they can also cause acute infections (ie, maxillary sinusitis associated with dental infections, intra-abdominal infections following perforation).6,7



•CNS infections
◦AGNB can cause various intracranial infections, including brain abscess, subdural empyema, epidural abscess, and meningitis (usually from contiguous spread from adjacent foci of infection). Brain abscesses are commonly caused by chronic infections in the ears, the mastoids, the sinuses, the oropharynx, the teeth, or the lungs.
◦Hematogenous spread can occur after dental, oropharyngeal, pulmonary, or intra-abdominal infection. Rarely, bacteremia of another origin or endocarditis leads to such infection.8 •Head and neck infections: Anaerobes, including AGNB, are recovered from various infections, especially in their chronic form. Head and neck infections include chronic otitis media9 ; sinusitis10 ; mastoiditis; tonsillar,10 peritonsillar, and retropharyngeal abscesses; cervical lymphadenitis; all deep neck space infections; thyroiditis; odontogenic infections; and postsurgical and nonsurgical head and neck wounds and abscesses.11 ◦Sinusitis is complicated by anaerobes, including AGNB, when it becomes chronic and oxygen levels decline. Anaerobes are isolated from 10% of patients with acute maxillary sinusitis (mostly secondary to odontogenic infection), but they are found in as many as 67% of chronic infections of the maxillary, ethmoid, frontal, and sphenoid sinuses.12,10 The infection may spread via anastomosing veins or contiguously to the CNS. Complications include orbital cellulitis, meningitis, cavernous sinus thrombosis, and epidural and subdural brain abscesses.
◦Tonsillitis, whether acute or chronic, may have AGNB involvement.13,10 AGNB can also be involved with tonsillitis complications, including internal jugular vein thrombophlebitis, which often causes postanginal sepsis. Prevotella species and other anaerobes are recovered from tonsillar or retropharyngeal abscesses without any aerobic bacteria, and they are isolated in cases of Vincent angina.
•Pleuropulmonary infections: Aspiration of oropharyngeal or gastric secretions and periodontal or gingival disease are risk factors for anaerobic pleuropulmonary infection due to AGNB and to other anaerobes. The infection can progress from pneumonitis to necrotizing pneumonia and lung abscess, with or without empyema.14 •Intra-abdominal infections15 ◦Secondary peritonitis and abdominal abscesses generally occur after entry of enteric organisms into the peritoneal cavity through perforation of the intestine or other viscus as a result of obstruction, infarction, or trauma.
◦The more distal the perforation, the more numerous the types and number of organisms that gain access into the peritoneal cavity (ie, perforations in the descending colon are associated with spillage of more organisms than perforations in proximal parts of the colon).
◦Enterotoxigenic B fragilis are considered an emerging enteropathogen-causing diarrhea.
•Female genital tract infection: These infections include bacterial vaginosis; soft tissue perineal, vulvar, and Bartholin gland abscesses; endometritis; pyometra; salpingitis; tubo-ovarian abscesses; adnexal abscess; pelvic inflammatory disease, which may include pelvic cellulitis and abscess; amnionitis; septic pelvic thrombophlebitis; intrauterine device–associated infection; septic abortion; and postsurgical obstetric and gynecologic infections.
•Skin and soft tissue infections
◦Infections involving AGNB include superficial infections, such as infected cutaneous ulcers, cellulitis, secondary diaper rash, gastrostomy or tracheostomy site wounds, infected subcutaneous sebaceous or inclusion cysts, eczema, scabies or kerion infections, paronychia, hidradenitis suppurativa, and pyoderma.
◦Subcutaneous tissue infections and postsurgical wound infections that may also involve the skin include cutaneous and subcutaneous abscesses, decubitus ulcers, infected diabetic (vascular or trophic) ulcers, breast abscesses, bite wounds,16 anaerobic cellulitis and gas gangrene, bacterial synergistic gangrene, infected pilonidal cyst or sinus, Meleney ulcer, and burn wound infection.
◦Deeper anaerobic soft tissue infections include necrotizing fasciitis, necrotizing synergistic cellulitis, gas gangrene, and crepitus cellulitis. These infections can involve the fascia alone or also the muscle surrounded by the fascia, inducing myositis and myonecrosis.
◦Anaerobic infections, such as decubitus ulcers or diabetic foot ulcers, are generally polymicrobial and are often complicated by osteomyelitis or bacteremia.
◦Deep tissue infections, such as necrotizing cellulitis, fasciitis, and myositis, often involve clostridial organisms and Staphylococcus pyogenes. They may be polymicrobic; may contain gas and gray, thin, putrid pus; and are associated with bacteremia and mortality.17 •Osteomyelitis and septic arthritis: Osteomyelitis in the long bones and the cranial and facial bones is frequently polymicrobic and may be associated with anaerobes in patients with peripheral vascular disease and decubitus ulcers.18 •Bacteremia
◦The prevalence of anaerobes, including AGNB, in bacteremia was once 5-15%. However, rates declined to 2-6% in the 1990s. Increased awareness of the importance of anaerobes and enhanced recognition of the types of clinical infection caused by these organisms, along with appropriate prophylaxis and treatment, have been proposed as explanations for the decreased incidence of anaerobic bacteremia from 1974–1988.19 However, recent studies have reported a resurgence in anaerobic bacteremia. A study from the Mayo Clinic (Rochester, MN) has reported that the mean incidence of anaerobic bacteremia increased from 53 cases per year during 1993–1996 to 75 cases per year during 1997–2000 to 91 cases per year during 2001–2004 (an overall increase of 74%).20 ◦The authors concluded that the sources of anaerobic bacteremia are now more varied than they once were, especially among immunosuppressed individuals and persons with complex underlying disease.
◦Which organisms are involved depends on their portal of entry and the underlying disease. The common isolates are the B fragilis group (60-75% of isolates).8 The B fragilis group and clostridial organisms are associated with a GI source.
◦Pigmented Prevotella, Porphyromonas, and Fusobacterium are associated with the oropharynx and a pulmonary source.
◦Fusobacterium species involve the female genital tract.
◦Propionibacterium acnes is associated with a foreign body.
◦Peptostreptococcus species are associated with all sources but especially with oropharyngeal, pulmonary, and female genital tract sources.
◦Predisposing factors include neoplasms; hematologic disorders; organ transplant; intestinal obstruction; decubitus ulcers; dental extraction; diabetes mellitus; postsplenectomy; use of cytotoxic agents or corticosteroids; total-body irradiation; and recent GI, obstetric, or gynecologic surgery.
◦Features typical of anaerobic bacteremia include metastatic lesions, hyperbilirubinemia, and suppurative thrombophlebitis.
◦The risk of mortality is 15-30% and improves with early appropriate antimicrobial therapy and resolution of the primary infection.

Causes
•Conditions that predispose to AGNB infections include the exposure of sterile sites to a high inoculum of indigenous mucous membrane florae; use of antibiotics that are ineffective against AGNB; reduced blood supply; and tissue necrosis, which lowers the oxidation-reduction potential and favors the growth of anaerobes. Conditions that lower the blood supply include trauma, foreign body, malignancy, surgery, edema, shock, colitis, and vascular disease.6,7 •Infection with aerobic bacteria can make the local tissue conditions more favorable for the growth of anaerobes. The host defenses can become impaired by anaerobic conditions and anaerobic bacteria.
•Anaerobic infection often manifests as suppuration, thrombophlebitis, abscess formation, and gangrenous destruction of tissue associated with gas.
•Anaerobes, including AGNB, are common in chronic infections. Therapy with antimicrobials, such as aminoglycosides, trimethoprim-sulfamethazine, and older quinolones, frequently fails to eradicate anaerobes.
•Certain infections that often involve anaerobes include brain abscess, oral or dental infections, human or animal bites, aspiration pneumonia, lung abscesses, amnionitis, endometritis, septic abortions, pelvic inflammatory disease, tubo-ovarian abscess, peritonitis following viscus perforation, abscesses in and around the oral and rectal areas, and pus-forming necrotizing infections of soft tissue or muscle.6,7 •Some tumors, such as colonic, uterine, and bronchogenic carcinomas and necrotic tumors of the head and the neck, can become infected with anaerobes.
More on Bacteroides Infection
Overview: Bacteroides Infection
Differential Diagnoses & Workup: Bacteroides Infection
Treatment & Medication: Bacteroides Infection
Follow-up: Bacteroides Infection

REF: http://emedicine.medscape.com/article/233339-overview . Acessado em 29/03/11

sexta-feira, 25 de fevereiro de 2011

Staphylococcus gallinarum

We describe a new species, Staphylococcus gallinarum, based on a study of characteristics of strains isolated from chickens and a pheasant. Strain CCM 3572 (= VIII1) is the type strain of this species. The chemical composition of the cell walls of the strains of this new species is similar to that of Staphylococcus epidermidis, but these organisms are resistant to novobiocin and produce acid from a wide range of carbohydrates. Staphylococcal strains isolated from goat milk belong to another new species, Staphylococcus caprae. The type strain is CCM 3573 (= 143.22). These strains are more closely related to S. epidermidis and Staphylococcus capitis than to other staphylococci.

REf: http://ijs.sgmjournals.org/cgi/content/abstract/33/3/480 Acessado em 25/02/11
Staphylococcus gallinarum and Staphylococcus caprae, Two New Species from Animals
L. A. DEVRIESE1, B. POUTREL2, R. KILPPER-BÄLZ3 and K. H. SCHLEIFER3
1 Faculty of Veterinary Medicine, University of Ghent, Casinoplein 24, B-9000 Ghent, Belgium
2 Station de Pathologie de la Reproduction, I.N.R.A., F-37380 Nouzilly, France
3 Lehrstuhl Microbiologie Technische UniversitäUt, München, D-8000 Munich 2, Federal Republic of Germany

domingo, 13 de fevereiro de 2011

Fungos

FUNGOS







Imagem de microscopia de varredura eletrônica (cores adicionadas) de micélio fúngico com as hifas (verde), esporângio (laranja) e esporos (azul), Penicillium sp. (aumento de 1560 x).





CARACTERÍSTICAS GERAIS



Durante muito tempo, os fungos foram considerados como vegetais e, somente a partir de 1969, passaram a ser classificados em um reino à parte.

Os fungos apresentam um conjunto de características próprias que permitem sua diferenciação das plantas: não sintetizam clorofila, não tem celulose na sue parede celular, exceto alguns fungos aquáticos e não armazenam amido como substância de reserva.

A presença de substâncias quitinosas na parede da maior parte das espécies fúngicas e a sua capacidade de depositar glicogênio os assemelham às células animais.

Os fungos são seres vivos eucarióticos, com um só núcleo, como as leveduras, ou multinucleados, como se observa entre os fungos filamentosos ou bolores.
Seu citoplasma contém mitocôndrias e retículo endoplasmático rugoso.

São heterotróficos e nutrem-se de matéria orgânica morta - fungos saprofíticos, ou viva—fungos parasitários.

Suas células possuem vida independente e não se reúnem para formar tecidos verdadeiros.

Os componentes principais da parede celular são hexoses e hexoaminas, que formam mananas, ducanas e galactanas. Alguns fungos têm parede rica em quitina (N-acetil glicosamina), outros possuem complexos polissacarídios e proteínas, com predominância de cisteína.

Fungos do gênero Cryptococcus, como o Cryptococcus neoformans apresentam cápsula de natureza polissacarídica, que envolve a parede celular.

Protoplastos de fungos podem ser obtidos peloo tratamento de seus cultivos, em condições hipertônicas, com enzimas de origem bacteriana ou extraídas do caracol Helix pomatia.

Os fungos são ubíquos, encontrando-se no solo, na água, nos vegetais, em animals, no homem e em detritos, em geral. O vento age como importante veiculo de dispersão de seus propágulos e fragmentos de hifa.





ESTRUTURA DOS FUNGOS



Os fungos podem se desenvolver em meios de cultivo especiais formando colônias de dois tipos:

- leveduriformes;

- filamentosas.

As colônias leveduriformes são pastosas ou cremosas, formadas por microrganismos unicelulares que cumprem as funções vegetativas e reprodutivas.

As colônias filamentosas podem ser algodonosas, aveludadas ou pulverulentas; são constituídas fundamentalmente por elementos multicelulares em forma de tubo—as hifas.

As hifas podem ser contínuas ou cenocíticas e tabicadas ou septadas. Possuem hifas septadas os fungos das Divisões Ascomycota, Basidiomycota e Deuteromycota e hifas cenocíticas, os das Divisões Mastigomycota e Zygomycota.



Ao conjunto de hifas, dá-se o nome de micélio. O micélio que se desenvolve no interior do substrato, funcionando também como elemento de sustentação e de absorção de nutrientes, é chamado de micélio vegetativo.
O micélio que se projeta na superficie e cresce acima do meio de cultivo é o micélio aéreo.
Quando o micélio aéreo se diferencia para sustentar os corpos de frutificação ou propágulos, constitui o micélio reprodutivo.

Os propágulos ou órgãos de disseminação dos fungos são classificados, segundo sua origem, em externos e intemos, sexuados e assexuados. Embora o micélio vegetativo não tenha especificamente funções de reprodução, alguns fragmentos de hifa podem se desprender do micélio vegetativo e cumprir funções de propagação, uma vez que as células fúngicas são autônomas.

Estes elementos são denominados de taloconídios e compreendem os:

- blastoconídios,

- artroconídios

- clamidoconídios.

Os blastoconídios, também denominados gêmulas, são comuns nas leveduras e se derivam por brotamento da célula-mãe. As vezes, os blastoconídios permanecem ligados à célula-mãe, formando cadeias, as pseudo-hifas, cujo conjunto é o pseudomicélio.



Os artroconídios são formados por fragmentação das hifas em segmentos retangulares. São encontratos nos fungos do gênero Geotrichum, em Coccidioides immitis e em dermatófitos.



Os clamidoconídios têm função de resistência, semelhante a dos esporos bacterianos. São células, geralmente arredondadas, de volume aumentado, com paredes duplas e espessas, nas quis se concentra o citoplasma. Sua localização no micélio pode ser apical ou intercalar. Formam-se em condições ambientais adversas, como escassez de nutrientes, de água e temperaturas não favoráveis ao desenvolvimento fúngico.



Entre outras estruturas de resistência devem ser mencionados os esclerócios ou esclerotos, que são corpúsculos duros e parenquimatosos, formados pelo conjunto de hifas e que permanecem em estado de dormência, até o aparecimento de condições adequadas para sua germinação. São encontrados em espécies de fungos das Divisões Ascomycota, Basidiomycota e Deuteromycota.





REPRODUÇÃO DOS FUNGOS



Os fungos se reproduzem em ciclos assexuais, sexuais e parassexuais.

Segundo Alexoupolos, a reprodução assexuada abrange quatro modalidades:

1) fragmentação de artroconídios;

2) fissão de células somáticas;

3) brotamento ou gemulação do blastoconídios-mãe;

4) produção de conídios.

Os conídios representam o modo mais comum de reprodução assexuada; são produzidos pelas transformações do sistema vegetativo do próprie micélio. As células que dão origem aos conídios são denominadas células conidiogênicas.

Os conídios podem ser hialinos ou pigmenntados, geralmente escuros - os feoconídios; apreentar formas diferentes— esféricos, fusiformes, cilíndricos, piriformes etc; ter parede lisa ou rugosa; serem formados de uma só célula ou terem septos em um ou dois planos; apresentar-se isolados ou agrupados.

As hifas podem produzir ramificações, algumas em plano perpendicular ao micélio, originando os conidióforos, a partir dos quais se formarão os conídios. Normalmente , os conídios se originam no extremo do conidióforo, que pode ser ramificado ou não. Outras vezes, o que não é muito freqüente, nascem em qualquer parte do micélio vegetativo, e neste caso são chamados de conídios sésseis, como no Trichophyton rubrum.

O conidióforo e a célula conidiogênica podem formar estruturas bem diferenciadas, peculiares, o aparelho de frutificação, também denominado de conidiação que permite a identificação de alguns fungos patogênicos.

No aparelho de conidiação tipo aspergilo, os conídios formam cadeias sobre fiálides, estruturas em forma de garrafa, em torno de uma vesícula que é uma dilatação na extremidade do conidióforo.





Conídios de Aspergillus agrupados em forma de cabeça, ao redor de uma vesícula.

Nos penicílios falta a vesícula na extremidade dos conidióforos que se ramificam dando a aparência de pincel.

Como no aspergilo, os conídios formam cadeias que se distribuem sobre as fiálides.

Quando um fungo filamentoso forma coníios de tamanhos diferentes, o maior será designado como macroconídio e o menor microconíidio.

Alguns fungos formam um corpo de frutificação piriforme denominado picnídio, dentro do qual se desenvolvem os conidióforos, com seus conídios—os picnidioconidios (Fig.7). Essa estrutura é encontrada na Pyrenochaeta romeroi, agente de eumicetoma.



Corte transversal de um picnídio mostrando conídios.

Os propágulos assexuados internos se originam de esporângios globosos, por um processo de clivagem de seu citoplasma, e são conhecidos como esporoangiosporos ou esporos. Pela ruptura do esporângio, os esporos são liberados.



Reprodução assexuada interna.


Os esporos sexuados se originam da fusão de estruturas diferenciadas com caráter de sexualidade. O núcleo haplóide de uma célula doadora funde-se com o núcleo haplóide de uma célula receptora, formando um zigoto. Posteriormente, por divisão meiótica, originam-se quatro ou oito núcleos haplóides, alguns dos quais se recombinarão, geneticamente.







Reprodução sexuada.

Os esporos sexuados internos são chamados ascosporos e se formam no interior de estruturas em forma de saco, denominadas ascos. Os ascos podem ser simples, como em leveduras dos gêneros Saccharomyces e Hansenula, ou se distribuir em lóculos ou cavidades do micélio, dentro de um estroma, o ascostroma ou ainda ester contidos em corpos de frutificação, os ascocarpos.

Três tipos de ascocarpos são bem conhecidos: cleistotécio, peritécio e apotécio.

O cleistotécio é uma estrutura globosa, fechada, de parede formada por hifas muito unidas, com um número indeterminado de ascos, contendo cada um oito ascosporos.

O peritécio é uma estrutura geralmente piriforme, dentro da qual os ascos nascem de uma camada hemenical e se dispõem em paliçada, exemplo, Leptosphaeria senegalensis, Neotestudina rosatii.

O apotécio é um ascocarpo aberto, em forma de cálice onde se localizam os ascos.




Diferentes tipos de ascos e ascocarpos.




Basidiosporos

Os fungos que se reproduzem por ascosporos ou basidiosporos são fungos perfeitos. As formas sexuadas são esporádicas e contribuem, através da recombinação genética, para o aperfeiçoamento da espécie. Em geral, estes fungos produzem também estruturas assexuadas, os conídios que asseguram sue disseminação. Muitos fungos, nos quais não foi até agora reconhecida a forma sexuada de reprodução, são incluídos entre os fungos imperfeitos. Quando é descrita a forma perfeita de um fungo, essa recebe uma outra denominação. Por exemplo, o fungo leveduriforme, Cryptococcus neoformans, em sue fase perfeita é denominado Filobasidiella neoformans.

A fase sexuada dos fungos é denominada te teleomórfica e a fase assexuada de anamórfica.

A maior parte das leveduras se reproduzem assexuadamente por brotamento ou gemulação e por fissão binária. No processo de brotamento, a célula-mãe origina um broto, o blastoconídio que cresce, recebe um núcleo após a divisão do núcleoda célula-mãe. Na fissão binária, a célula-mãe se divide em duas células de tamanhos iguais, de forma semelhante a que ocorre com as. bactérias. No seu ciclo evolutivo, algumas leve auras, como Saccharomyces cerevisiae, podem originar esporos sexuados, ascosporos, depois que duas células experimentam fusão celular e nuclear, seguida de meiose.

O fenômeno de parassexualidade foi demonstrado em Aspergillus. Consiste na fusão de hifas e formação de um heterocarion que contém núcleos haplóides. Às vezes, estes núcleos se fundem e originam núcleos diplóides, heterozigóticos, cujos cromossomas homólogos sofrem recombinação duruante a mitose. Apesar destes recombinantes serem raros, o ciclo parassexual é importante na evolução de alguns fungos. A tabela abaixo apresenta, de forma esquemática, os conceitos mencionados.





METABOLISMO



Os fungos são microrganismos heterotróficos e, em sue maioria, aeróbios obrigatórios. No entanto, certas leveduras fermentadoras, aeróbias facultativas, se desenvolvem em ambientes com pouco oxigênio ou mesmo na ausência deste elemento.

Os fungos podem germinar, ainda que lentamente, em atmosfera de reduzida quantidade de oxigênio. O crescimento vegetativo e a reprodução assexuada ocorrem nessas condições, enquanto a reprodução sexuada se efetua apenas em atmosfera rica em oxigênio.

Em condições aeróbicas, a via da hexose monofosfato é a responsável por 30% da glicó1ise. Sob condições anaeróbicas, a via clássica, usada pela maioria das leveduras, é a de Embden-Meyerhof, que resulta na formação de piruvato.

Algumas leveduras, como o Saccharomyces cerevisiae fazem o processo de fermentação alcoó1ica de grande importancia industrial, na fabricação de bebidas e na panificação.

Os fungos produzem enzimas como lipases, invertases, lactases, proteinases, amilases etc., que hidrolisam o substrato tornando-o assimilável através de mecanismos de transporte ativo e passivo. Alguns substratos podem induzir a formação de enzimas degradativas; há fungos que hidrolisam substâncias orgânicas, como quitina, osso, couro, inclusive materiais plásticos.

Muitas espécies fúngicas podem se desenvolver em meios mínimos, contendo amônia ou nitritos, como fontes de nitrogênio. As substãâncias orgânicas, de preferência, são carboidratos simples como D-glicose e sais minerais como sulfatos e fosfatos.

Oligoelementos como ferro, zinco, manganês, cobre, molibdênio e cálcio são exigidos em pequenas quantidades. No entanto, alguns fungos requerem fatores de crescimento, que não conseguem sintetizar, em especial, vitaminas, como tiamina, biotina, riboflavina, ácido pantotênico etc.

Os fungos, como todos os seres vivos, necessitam de água para o seu desenvolvimento. Alguns são halofílicos, crescendo em ambiente com elevada concentração de sal.

A temperatura de crescimento abrange uma larga faixa, havendo espécies psicrôfilas, mesófilas e termófilas. Os fungos de importância médica, em geral, são mesófilos, apresentando temperatura ótima, entre 20° e 30°C.

Os fungos podem ter morfologia diferente, segundo as condições nutricionais e a temperatura de seu desenvolvimento. O fenômeno de variação morfolôgica mais importante em micologia médica é o dimorfismo, que se expressa por um crescimento micelial entre 22° e 28°C e leveduriforme entre 35°C e 37°C. Em geral, essas formas são reversíveis. A fase micelial (M) ou saprofítica é a forma infectante e está presente no solo, nas plantas etc. A fase leveduriforme (L ou Y) ou parasitaria é encontrada nos tecidos. Este fenômeno é conhecido como dimorfismo fúngico e se observe entre fungos de importância médica, como Histoplasma capsulatum, Blastomyces dermatitidis, Paracoccidioides brasiliensis, Sporothrix schenckii. Na Candida albicans a forma saprofítica infectante é a leveduriforme e a forma parasitária, isolada dos tecidos, é a micelial. Em laboratório, é possível reproduzir o dimorfismo mediante variações de temperatura de incubação, de tensão de O2 e de meios de cultura específicos. Desta forma foi possível classificar como dimórficos, fungos nos quais era conhecida apenas uma das formas, por exemplo, os agentes de cromoblastomicose.

O pleomorfismo nos dermatófitos se expressa através da perda das estruturas de reprodução ou conídios, com variações morfológicas da colônia. Essas estruturas podem ser recuperadas nos retro cultivos, após a inoculação em animais de laboratório ou em meios enriquecidos com terra.

Ainda que o pH mais favorável ao desenvolvimento dos fungos esteja entre 5, 6 e 7, a maioria dos fungos tolera amplas variações de pH. Os fungos filamentosos podem crescer na faixa entre 1,5 e 11, mas as leveduras não toleram pH alcalino. Muitas vezes, a pigmentação dos fungos está relacionada com o pH do substrato. Os meios com pH entre 5 e 6, com elevadas concentrações de açúcar, alta pressão osmótica, taiss como geléias, favorecem o desenvolvimento dos fungos nas porções em contato com o ar.

O crescimento dos fungos é mais lento que o das bactérias e sues culturas precisam, em média, de 7 a 15 dias, ou mais de incubação. Com a finalidade de evitar o desenvolvimento bacteriano, que pode inibir ou se sobrepor ao do fungo, é necessário incorporar aos meios de cultura, antibacterianos de largo espectro, como o cloranfenicol. Também pode-se acrescentar cicloheximida para diminuir o crescimento de fungos saprófitas contaminantes, de cultivos de fungos patogênicos.

Muitas espécies fúngicas exigem luz para seu desenvolvimento; outras são por ela inibidos e outras ainda mostram-se indiferentes a este agente. Em geral, a luz solar direta, devido à radiação ultravioleta, é elemento fungicida.

Por diferentes processos, os fungos podem elaborar vários metabó1itos, como antibióticos, dos quais a penicilina é o mais conhecido e micotoxinas, como aflatoxinas, que Ihes conferem vantagens seletivas.





CLASSIFICAÇÃO DOS FUNGOS



O Reino Fungi é dividido em seis filos ou divisões dos quais quatro são de importância médica: Zygomycota, Ascomycota, Basidiomycota e Deuteromycota.

DIVISÃO ZYGOMYCOTA

Inclui fungos de micélio cenocítico, ainda que septos podem separar estruturas como os esporângios. A reprodução pode ser sexuada, pela formação de zigosporos e assexuada com a produção de esporos, os esporangiosporos, no interior dos esporangios.

Os fungos de interesse médico se encontram nas ordens Mucorales e Entomophthorales.

DIVISÃO ASCOMYCOTA

Agrupa fungos de hifas septadas, sendo o septo incompleto, com os típicos corpos de Woronin. A sua principal característica é o asco, estrutura em forma de saco ou bolsa, no interior do qual são produzidos os ascosporos, esporos sexuados, com forma, número e cor variáveis para cada espécie. Algumas espéeies produzem ascocarpos e ascostromas no interior dos quais se formam os ascos Conídios, propágulos assexuados. são também encontrados.

As espécies patogênicas para o homem se classificam em três classes: Hemiascomycetes, Loculoascomycetes e Plectomycetes.

DIVISÃO BASIDIOMYCOTA

Compreende fungos de hifas septadas, que se caracterizam pela produção de esporos sexuados, os basidiosporos, típicos de cada espécie. Conídios ou propágulos assexuados podem ser encontrados. A espécie patogênica mais importante se enquadra na classe Teliomycetes.


Principais estruturas de Basidiomycota.

DlVISÃO DEUTEROMYCOTA

Engloba fungos de hifas septadas que se multiplicam apenas por conídios e por isso são conhecidos como Fungos Imperfeitos. Os conídios podem ser exógenos ou estar contidos em estruturas como os picnídios. Entre os Deuteromycota se encontra a maior parte dos fungos de importância médica.

REF: http://www.enq.ufsc.br/labs/probio/disc_eng_bioq/trabalhos_pos2003/const_microorg/fungos.htm. Acessado em 13/02/11

sábado, 12 de fevereiro de 2011

Bacillus firmus

B. firmus, a nontoxic, nonpathogenic G+ bacterium of external environment

REF: http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6T75-3V8RNPB-G&_user=10&_coverDate=12%2F31%2F1998&_rdoc=1&_fmt=high&_orig=search&_origin=search&_sort=d&_docanchor=&view=c&_searchStrId=1630442144&_rerunOrigin=google&_acct=C000050221&_version=1&_urlVersion=0&_userid=10&md5=ae294f1696f072400f30c8f4ddb4d407&searchtype=a

Information preview for Bacillus firmus:
Notes
Does not grow at 50 degrees C; pink colonies may occur; eliptical central spores which do not swell the cell body.
Ecology
Found in soil.
http://web.gideononline.com/abstract.php?module=microbiology&type=bacteria&code=390&view=General

Actinomyces naeslundii

Actinomyces naeslundii is a gram-positive, rod-shaped, non-spore-forming, non-acid-fast, facultative anaerobe found in the oral cavity of humans and other animals. This non-motile bacillus is one of only a few gram-positive bacteria characterized as having fimbriae (Wu et al., 2001). The type 1 fimbriae of A. naeslundii mediate adhesion of this organism to the tooth surface (Chen et al., 2007). This microorganism is mesophilic and grows in temperatures ranging from 15°C to 40°C with an optimum growing temperature of 37°C, the normal human body temperature. Actinomyces naeslundii is commonly found in large numbers in the oral cavity and is a major component of dental plaque. It has also been linked to root caries, periodontal disease and even opportunistic infections such as actinomycosis.
Actinomycosis is a chronic bacterial infection caused by certain species of the genus Actinomyces such as A. naeslundii, A. viscosus and A. odontolyticus. The most common clinical form of actinomycosis is cervicofacial, but thoracic and abdominal actinomycosis, as well as pelvic actinomycosis in women, are also possible. Common infection sites are decayed teeth, the lungs and the intestines. However, Actinomycosis can occur in nearly every organ and the infection is usually a mix of several Actinomyces and other bacterial species, including gram-negative species (NCBI). Actinomycosis is often hard to identify and is sometimes referred to as the "most misdiagnosed disease" (Jin et al., 2001).


REF:?????

Aspergillus spp

Growth and distribution
Aspergillus species are highly aerobic and are found in almost all oxygen-rich environments, where they commonly grow as molds on the surface of a substrate, as a result of the high oxygen tension. Commonly, fungi grow on carbon-rich substrates such as monosaccharides (such as glucose) and polysaccharides (such as amylose). Aspergillus species are common contaminants of starchy foods (such as bread and potatoes), and grow in or on many plants and trees.
In addition to growth on carbon sources, many species of Aspergillus demonstrate oligotrophy where they are capable of growing in nutrient-depleted environments, or environments in which there is a complete lack of key nutrients. A. niger is a prime example of this; it can be found growing on damp walls, as a major component of mildew.
Pathogens
Some Aspergillus species cause serious disease in humans and animals. The most common causing pathogenic species are Aspergillus fumigatus and Aspergillus flavus. Aspergillus flavus produces aflatoxin which is both a toxin and a carcinogen, and which can potentially contaminate foods such as nuts. The most common causing allergic disease are Aspergillus fumigatus and Aspergillus clavatus. Other species are important as agricultural pathogens. Aspergillus spp. cause disease on many grain crops, especially maize, and synthesize mycotoxins including aflatoxin.

ref: ?????

Bacillus

Gênero Bacillus spp
Prof. Marcos JP Gomes
ATUALIDADES
Atualmente (2009-2) na “List of Prokaryotic names with Standing in Nomenclature”
do pesquisador J.P. Euzéby há citação de 230 espécies e de 5 subespécies no gênero
Bacillus spp, conforme o site http://www.bacterio.cict.fr/b/bacillus.html
CARACTERÍSTICAS GERAIS DO GÊNERO
O gênero Bacillus (família Bacillaceae) é extremamente heterogêneo, tanto
geneticamente (o G + C % das diversas espécies variam de 32 a 69) quanto fenotipicamente
(tipo respiratório, metabolismo dos açúcares, composição da parede etc). Os estudos do
ARNr 16S e 23S confirmaram essa heterogeneidade e mostraram que o gênero Bacillus
pode ser dividido em muitos gêneros.
Ash e colaboradores, em 1991, utilizaram a análise seqüencial do ARNr 16S de 51
espécies classificaram e caracterizaram em 5 grupos filogenéticos. A organização foi
iniciada em 1992 para criação do gênero Alicyclobacillus que agrupou três espécies
acidófilas e termófilas.
Posteriormente, foram propostos e validados outros gêneros incluindo:
Aneurinibacillus (1996), Brevibacillus (1996), Gracilibacillus (1999), Geobacillus (2001),
Marinibacillus (2001), Paenibacillus (1994), Salibacillus (1999), Ureibacillus (2001),
Virgibacillus (1998) e Lysinibacillus (2007), todos com pelo menos, uma espécie,
inicialmente incluída no gênero Bacillus. O gênero Amphibacillus (1990), Filobacillus
(2001), Jeotgalibacillus (2001) e Halobacillus (1996) são igualmente constituídos de
bacilos Gram positivos, esporulados, aeróbios ou aero-anaeróbios.
CARACTERÍSTICAS MORFOLOCICAS, CULTURAIS E BIOQUIMICAS.
As espécies do gênero Bacillus são bastonetes com extremidades retas ou
arredondadas de tamanhos variáveis (0,5 X 1,2 m até 2,5 x 10 m), esporulados, Gram
positivos ou Gram variáveis (coloração de Gram não é positiva nos cultivos jovens);
Geralmente móveis graças aos cílios peritríquios.
O B. anthracis e o B. mycoides são imóveis. Nas espécies móveis, a motilidade é
variável, segundo a linhagem.
Algumas espécies são capsuladas (B. anthracis, B. licheniformis, B. megaterium e B.
subtilis podem elaborar cápsula formada de polímeros de ácido glutâmico); aeróbios ou
anaeróbios; geralmente catalase positivos; são variáveis ao teste da oxidase.
O cultivo desses microrganismos pode ser difícil, visto que algumas espécies podem
exigir inúmeros fatores de crescimento; aspecto colonial no agar são variáveis e o
fenômeno de dissociação são freqüentes.
O B. anthracis, B. cereus, B. thuringiensis e o B. weihenstephanensis formam
colônias de tamanho grande (2 a 7 mm de diâmetro), foscas ou granulosas e de forma
variáveis (circulares ou não, bordos regulares ou denteadas ou filamentosas).
O B. mycoides e o B. pseudomycoides produzem colônias rizóides e aderentes que se
espalham por todas a superfície do agar em 48 hs.

ref: Disciplina de Microbiologia Clínica Veterinária
FAVET-UFRGS
40 Semestre 2009-2
http://www.ufrgs.br/labacvet/pdf/bacillus200902.pdf em 06/05/10