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
sexta-feira, 29 de julho de 2011
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
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
- http://www.bacteriamuseum.org/cms/Bacterial-Species-Cabinet/
- http://www.fda.gov/
- http://dg3.eudra.org/
- http://www.emea.eu.int/
- http://heads.medagencies.org/
- http://www.mhra.gov.uk/
- http://heads.medagencies.org/germany.html
- www. infarmed.pt/index2.html
- http://agmed.sante.gouv.fr/
- www.msc.es/agemed
- http://www.afigp.fgov.be/
- http://www.legemiddelverket.no/
- www.mpa.se/eng/index.html
- www.nam.fi/english/index.html
- www.ministerosalute.it/medicinali
- http://ec.europa.eu/health/documents/eudralex/vol-4/index_en.htm
- http://www.gmp-compliance.org/eca_link_navigator.html
- www.cbg-med-nl
- Australia - Therapeutic Goods Administration (TGA) - www.tga.gov.au
- Bulgaria - Bulgarian Drug Agency - www.bda.bg/web_engl/main.htm
- Canada - Therapeutic Products Diretorate (TPD) - www.hc-sc.gc.ca/hpb-dgps/therapeutic/htmleng
- Chile - Chile Regulatory Agency - www.minsal.cl
- Russia - Czech Republic - www.sukl.cz/enindex.htm
- Denmanrk - The Danish Medicines Agency - www.laegemiddelstyrelsen.dk/index_en.htm
- Estonia - State Agency of medicines - www.dam.ee
- Greece - EOD - www.eof.gr
- Hong Kong - Hong Kong Department od Health Welfare and Food - www.fwfb.gov.hk/eindex.html
- India - Ministry of health and family welfare - http://mohfw.nic.in
- Ireland - Irish Medicine Board - www.imb.ie
- Japan - Ministry of Health, Labour and Welfare - (MHLW) - www.mhlw.go.jp/english
- Russia - Ministry of Health of the Russian Federation - www.minsalud.gov.com
- 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
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
^ 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
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
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