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1.
Sci Rep ; 8(1): 9734, 2018 06 27.
Artigo em Inglês | MEDLINE | ID: mdl-29950676

RESUMO

Crohn's disease (CD) patients who undergo ileocolonic resection (ICR) typically have disease recurrence at the anastomosis which has been linked with a gut dysbiosis. The aims of this study were to define the mucosa-associated microbiota at the time of ICR and to determine if microbial community structure at the time of surgery was predictive of future disease relapse. Ileal biopsies were obtained at surgery and after 6 months from CD subjects undergoing ICR. Composition and function of mucosal-associated microbiota was assessed by 16S rRNA sequencing and PICRUSt analysis. Endoscopic recurrence was assessed using the Rutgeerts score. Analysis of mucosal biopsies taken at the time of surgery showed that decreased Clostridiales together with increased Enterobacteriales predicted disease recurrence. An increase in the endospore-forming Lachnospiraceae from surgery to 6 months post-ICR was associated with remission. A ratio of 3:1 between anaerobic endospore-forming bacterial families and aerobic families within the Firmicutes phylum was predictive of maintenance of remission. Gut recolonization following ICR is facilitated by microbes which are capable of either aerobic respiration or endospore formation. The relative proportions of these species at the time of surgery may be predictive of subsequent microbial community restoration and disease recurrence.


Assuntos
Doença de Crohn/microbiologia , Doença de Crohn/patologia , Bactérias Formadoras de Endosporo/fisiologia , Bactérias Formadoras de Endosporo/genética , Feminino , Firmicutes/genética , Firmicutes/isolamento & purificação , Microbioma Gastrointestinal/genética , Microbioma Gastrointestinal/fisiologia , Humanos , Íleo/cirurgia , Análise dos Mínimos Quadrados , Masculino , Pessoa de Meia-Idade , RNA Ribossômico 16S/genética , Indução de Remissão
2.
Sci Rep ; 8(1): 6448, 2018 04 24.
Artigo em Inglês | MEDLINE | ID: mdl-29691456

RESUMO

Concrete is a strong and fairly inexpensive building substance, but has several disadvantages like cracking that allows corrosion, thus reducing its lifespan. To mitigate these complications, long-lasting microbial self-healing cement is an alternative that is eco-friendly and also actively repairs cracks. The present paper describes the detailed experimental investigation on compressive strength of cement mortars, mixed with six alkaliphilic bacteria, isolated from subsurface mica mines of high alkalinity. The experiments showed that the addition of alkaliphilic isolates at different cell concentrations (104 and 106 cells/ml) enhanced the compressive strength of cement mortar, because the rapid growth of bacteria at high alkalinity precipitates calcite crystals that lead to filling of pores and densifying the concrete mix. Thus, Bacillus subtilis (SVUNM4) showed the highest compressive strength (28.61%) of cement mortar at 104 cells/ml compared to those of other five alkaliphilic isolates (Brevibacillus sp., SVUNM15-22.1%; P. dendritiformis, SVUNM11-19.9%; B. methylotrophicus, SVUNM9-16%; B. licheniformis, SVUNM14-12.7% and S. maltophilia, SVUNM13-9.6%) and controlled cement mortar as well. This method resulted in the filling of cracks in concrete with calcite (CaCO3), which was observed by scanning electron microscopy (SEM). Our results showed that the alkaliphilic bacterial isolates used in the study are effective in self-healing and repair of concrete cracks.


Assuntos
Materiais de Construção/microbiologia , Bactérias Formadoras de Endosporo/metabolismo , Microbiologia Industrial/métodos , Álcalis/química , Bacillus/química , Bacillus/isolamento & purificação , Bacillus subtilis/química , Bacillus subtilis/metabolismo , Brevibacillus/química , Brevibacillus/isolamento & purificação , Carbonato de Cálcio/química , Força Compressiva , Microscopia Eletrônica de Varredura , Paenibacillus/química , Paenibacillus/isolamento & purificação , Stenotrophomonas/química , Stenotrophomonas/isolamento & purificação
3.
Chemosphere ; 186: 202-208, 2017 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-28779595

RESUMO

A pilot-scale investigation of membrane-based aerobic digestion system dominated by endospore-forming bacteria was evaluated as one of the potential sludge treatment processes (STP). Most of the organic matter in the sludge was removed (90.1%) by the particular bacteria in the STP, which consisted of mixed liquor suspended solid (MLSS) contact reactor (MCR), MLSS oxidation reactor (MOR), and membrane bioreactor (MBR). The sludge was accumulated in the MBR without wasting, and then the effluent in STP was fed into the first step in water resource recovery facility (WRRF). According to the analysis of microbial communities in all reactors, various Bacillus species were present in the STP, mainly due to their intrinsic resistance to the extreme conditions. As the surviving Bacillus species might consume degraded microorganisms for their growth, these endospore-forming bacteria-based STP could be suitable for the sludge reduction when they operated for a long time.


Assuntos
Reatores Biológicos/microbiologia , Bactérias Formadoras de Endosporo/fisiologia , Esgotos/microbiologia , Eliminação de Resíduos Líquidos/métodos , Aerobiose , Projetos Piloto
4.
Mol Microbiol ; 104(4): 535-538, 2017 05.
Artigo em Inglês | MEDLINE | ID: mdl-28207180

RESUMO

Certain endospore-forming soil dwelling bacteria are important human, animal or insect pathogens. These organisms produce spores containing an outer layer, the exosporium. The exosporium is the site of interactions between the spore and the soil environment and between the spore and the infected host during the initial stages of infection. The composition and assembly process of the exosporium are poorly understood. This is partly due to the extreme stability of the exosporium that has proven to be refractive to existing methods to deconstruct the intact structure into its component parts. Although more than 20 proteins have been identified as exosporium-associated, their abundance, relationship to other proteins and the processes by which they are assembled to create the exosporium are largely unknown. In this issue of Molecular Microbiology, Terry, Jiang, and colleagues in Per Bullough's laboratory show that the ExsY protein is a major structural protein of the exosporium basal layer of B. cereus family spores and that it can self-assemble into complex structures that possess many of the structural features characteristic of the exosporium basal layer. The authors refined a model for exosporium assembly. Their findings may have implications for exosporium formation in other spore forming bacteria, including Clostridium species.


Assuntos
Esporos Bacterianos/metabolismo , Bacillus cereus/metabolismo , Proteínas de Bactérias/metabolismo , Parede Celular/metabolismo , Bactérias Formadoras de Endosporo , Microbiologia do Solo
5.
BMC Microbiol ; 15: 240, 2015 Oct 28.
Artigo em Inglês | MEDLINE | ID: mdl-26511622

RESUMO

BACKGROUND: Biosurfactants are surface-active biomolecules with great applicability in the food, pharmaceutical and oil industries. Endospore-forming bacteria, which survive for long periods in harsh environments, are described as biosurfactant producers. Although the ubiquity of endospore-forming bacteria in saline and hypersaline environments is well known, studies on the diversity of the endospore-forming and biosurfactant-producing bacterial genera/species in these habitats are underrepresented. METHODS: In this study, the structure of endospore-forming bacterial communities in sediment/mud samples from Vermelha Lagoon, Massambaba, Dois Rios and Abraão Beaches (saline environments), as well as the Praia Seca salterns (hypersaline environments) was determined via denaturing gradient gel electrophoresis. Bacterial strains were isolated from these environmental samples and further identified using 16S rRNA gene sequencing. Strains presenting emulsification values higher than 30 % were grouped via BOX-PCR, and the culture supernatants of representative strains were subjected to high temperatures and to the presence of up to 20 % NaCl to test their emulsifying activities in these extreme conditions. Mass spectrometry analysis was used to demonstrate the presence of surfactin. RESULTS: A diverse endospore-forming bacterial community was observed in all environments. The 110 bacterial strains isolated from these environmental samples were molecularly identified as belonging to the genera Bacillus, Thalassobacillus, Halobacillus, Paenibacillus, Fictibacillus and Paenisporosarcina. Fifty-two strains showed emulsification values of at least 30%, and they were grouped into 18 BOX groups. The stability of the emulsification values varied when the culture supernatants of representative strains were subjected to high temperatures and to the presence of up to 20% NaCl. The presence of surfactin was demonstrated in one of the most promising strains. CONCLUSION: The environments studied can harbor endospore-forming bacteria capable of producing biosurfactants with biotechnological applications. Various endospore-forming bacterial genera/species are presented for the first time as biosurfactant producers.


Assuntos
Bactérias Aeróbias/isolamento & purificação , Bactérias Aeróbias/metabolismo , Bactérias Formadoras de Endosporo/isolamento & purificação , Bactérias Formadoras de Endosporo/metabolismo , Microbiologia Ambiental , Tensoativos/metabolismo , Bactérias Aeróbias/classificação , Bactérias Aeróbias/genética , Brasil , Análise por Conglomerados , DNA Bacteriano/química , DNA Bacteriano/genética , DNA Ribossômico/química , DNA Ribossômico/genética , Bactérias Formadoras de Endosporo/classificação , Bactérias Formadoras de Endosporo/genética , Espectrometria de Massas , Dados de Sequência Molecular , Filogenia , RNA Ribossômico 16S/genética , Análise de Sequência de DNA , Cloreto de Sódio/metabolismo
6.
FEMS Microbiol Lett ; 362(22)2015 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-26449556

RESUMO

Autoinducer-2 (AI-2) is a quorum-sensing (QS) molecule which mediates interspecies signaling and affects various bacterial behaviors in food fermentation. Biosynthesis of AI-2 is controlled by S-ribosylhomocysteine lyase encoded by the luxS gene. The objective of this study was to investigate production of AI-2 by aerobic endospore-forming bacteria (AEB) isolated from the West African alkaline fermented seed products Mantchoua and Maari. The study included 13 AEB strains of Bacillus subtilis, B. cereus, B. altitudinis, B. amyloliquefaciens, B. licheniformis, B. aryabhattai, B. safensis, Lysinibacillus macroides and Paenibacillus polymyxa. All the tested strains harbored the luxS gene and all strains except for P. polymyxa B314 were able to produce AI-2 during incubation in laboratory medium. Production of AI-2 by AEB was growth phase dependent, showing maximum activity at the late exponential phase. AI-2 was depleted from the culture medium at the beginning of the stationary growth phase, indicating that the tested AEB possess a functional AI-2 receptor that internalizes AI-2. This study provides the evidences of QS system in Bacillus spp. and L. macroides and new knowledge of AI-2 production by AEB. This knowledge contributes to the development of QS-based strategies for better control of alkaline fermentation.


Assuntos
Bacillaceae/metabolismo , Bactérias Aeróbias/metabolismo , Bactérias Formadoras de Endosporo/metabolismo , Microbiologia de Alimentos , Homosserina/análogos & derivados , Lactonas/metabolismo , Paenibacillus/metabolismo , África Ocidental , Bacillaceae/genética , Bacillaceae/crescimento & desenvolvimento , Bacillaceae/isolamento & purificação , Bactérias Aeróbias/genética , Bactérias Aeróbias/crescimento & desenvolvimento , Bactérias Aeróbias/isolamento & purificação , Proteínas de Bactérias/genética , Transporte Biológico , Liases de Carbono-Enxofre/genética , Meios de Cultura/química , Bactérias Formadoras de Endosporo/genética , Bactérias Formadoras de Endosporo/crescimento & desenvolvimento , Bactérias Formadoras de Endosporo/isolamento & purificação , Fermentação , Homosserina/metabolismo , Paenibacillus/genética , Paenibacillus/crescimento & desenvolvimento , Paenibacillus/isolamento & purificação , Percepção de Quorum
7.
J Microbiol Biotechnol ; 24(5): 648-60, 2014 May.
Artigo em Inglês | MEDLINE | ID: mdl-24548930

RESUMO

Doenjang, a traditional Korean fermented soybean paste, is made by mixing and ripening meju with high salt brine (approximately 18%). Meju is a naturally fermented soybean block prepared by soaking, steaming, and molding soybean. To understand living bacterial community migration and the roles of bacteria in the manufacturing process of doenjang, the diversity of culturable bacteria in meju and doenjang was examined using media supplemented with NaCl, and some physiological activities of predominant isolates were determined. Bacilli were the major bacteria involved throughout the entire manufacturing process from meju to doenjang; some of these bacteria might be present as spores during the doenjang ripening process. Bacillus siamensis was the most populous species of the genus, and Bacillus licheniformis exhibited sufficient salt tolerance to maintain its growth during doenjang ripening. Enterococcus faecalis and Enterococcus faecium, the major lactic acid bacteria (LAB) identified in this study, did not continue to grow under high NaCl conditions in doenjang. Enterococci and certain species of coagulase-negative staphylococci (CNS) were the predominant acid-producing bacteria in meju fermentation, whereas Tetragenococcus halophilus and CNS were the major acid-producing bacteria in doenjang fermentation. We conclude that bacilli, LAB, and CNS may be the major bacterial groups involved in meju fermentation and that these bacterial communities undergo a shift toward salt-tolerant bacilli, CNS, and T. halophilus during the doenjang fermentation process.


Assuntos
Bactérias/classificação , Fermentação , Microbiologia de Alimentos , Alimentos de Soja/microbiologia , Ácidos/metabolismo , Bacillus/classificação , Bactérias/efeitos dos fármacos , Bactérias/crescimento & desenvolvimento , Carga Bacteriana , Fenômenos Fisiológicos Bacterianos , Proteínas de Bactérias/metabolismo , Bactérias Formadoras de Endosporo , Enzimas/metabolismo , Microbiota , Cloreto de Sódio/farmacologia
8.
Microbiol Spectr ; 2(5)2014 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-26104376

RESUMO

Endospore formation follows a complex, highly regulated developmental pathway that occurs in a broad range of Firmicutes. Although Bacillus subtilis has served as a powerful model system to study the morphological, biochemical, and genetic determinants of sporulation, fundamental aspects of the program remain mysterious for other genera. For example, it is entirely unknown how most lineages within the Firmicutes regulate entry into sporulation. Additionally, little is known about how the sporulation pathway has evolved novel spore forms and reproductive schemes. Here, we describe endospore and internal offspring development in diverse Firmicutes and outline progress in characterizing these programs. Moreover, comparative genomics studies are identifying highly conserved sporulation genes, and predictions of sporulation potential in new isolates and uncultured bacteria can be made from these data. One surprising outcome of these comparative studies is that core regulatory and some structural aspects of the program appear to be universally conserved. This suggests that a robust and sophisticated developmental framework was already in place in the last common ancestor of all extant Firmicutes that produce internal offspring or endospores. The study of sporulation in model systems beyond B. subtilis will continue to provide key information on the flexibility of the program and provide insights into how changes in this developmental course may confer advantages to cells in diverse environments.


Assuntos
Bactérias Formadoras de Endosporo/crescimento & desenvolvimento , Firmicutes/crescimento & desenvolvimento , Esporos Bacterianos/crescimento & desenvolvimento , Bactérias Formadoras de Endosporo/genética , Bactérias Formadoras de Endosporo/metabolismo , Firmicutes/genética , Firmicutes/metabolismo , Regulação Bacteriana da Expressão Gênica , Modelos Biológicos , Transdução de Sinais , Esporos Bacterianos/genética , Esporos Bacterianos/metabolismo
9.
Microbiol Spectr ; 2(6)2014 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-26104459

RESUMO

Plasmid-encoded virulence factors are important in the pathogenesis of diseases caused by spore-forming bacteria. Unlike many other bacteria, the most common virulence factors encoded by plasmids in Clostridium and Bacillus species are protein toxins. Clostridium perfringens causes several histotoxic and enterotoxin diseases in both humans and animals and produces a broad range of toxins, including many pore-forming toxins such as C. perfringens enterotoxin, epsilon-toxin, beta-toxin, and NetB. Genetic studies have led to the determination of the role of these toxins in disease pathogenesis. The genes for these toxins are generally carried on large conjugative plasmids that have common core replication, maintenance, and conjugation regions. There is considerable functional information available about the unique tcp conjugation locus carried by these plasmids, but less is known about plasmid maintenance. The latter is intriguing because many C. perfringens isolates stably maintain up to four different, but closely related, toxin plasmids. Toxin genes may also be plasmid-encoded in the neurotoxic clostridia. The tetanus toxin gene is located on a plasmid in Clostridium tetani, but the botulinum toxin genes may be chromosomal, plasmid-determined, or located on bacteriophages in Clostridium botulinum. In Bacillus anthracis it is well established that virulence is plasmid determined, with anthrax toxin genes located on pXO1 and capsule genes on a separate plasmid, pXO2. Orthologs of these plasmids are also found in other members of the Bacillus cereus group such as B. cereus and Bacillus thuringiensis. In B. thuringiensis these plasmids may carry genes encoding one or more insecticidal toxins.


Assuntos
Proteínas de Bactérias/genética , Toxinas Bacterianas/genética , Bactérias Formadoras de Endosporo/genética , Plasmídeos , Fatores de Virulência/genética , Bactérias Formadoras de Endosporo/patogenicidade , Virulência
10.
J Bacteriol ; 195(2): 253-60, 2013 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-23123912

RESUMO

The capacity to form endospores is unique to certain members of the low-G+C group of Gram-positive bacteria (Firmicutes) and requires signature sporulation genes that are highly conserved across members of distantly related genera, such as Clostridium and Bacillus. Using gene conservation among endospore-forming bacteria, we identified eight previously uncharacterized genes that are enriched among endospore-forming species. The expression of five of these genes was dependent on sporulation-specific transcription factors. Mutants of none of the genes exhibited a conspicuous defect in sporulation, but mutants of two, ylxY and ylyA, were outcompeted by a wild-type strain under sporulation-inducing conditions, but not during growth. In contrast, a ylmC mutant displayed a slight competitive advantage over the wild type specific to sporulation-inducing conditions. The phenotype of a ylyA mutant was ascribed to a defect in spore germination efficiency. This work demonstrates the power of combining phylogenetic profiling with reverse genetics and gene-regulatory studies to identify unrecognized genes that contribute to a conserved developmental process.


Assuntos
Bacillus subtilis/crescimento & desenvolvimento , Bacillus subtilis/genética , Bactérias Formadoras de Endosporo/crescimento & desenvolvimento , Bactérias Formadoras de Endosporo/genética , Genes Bacterianos , Esporos Bacterianos/crescimento & desenvolvimento , Esporos Bacterianos/genética , Sequência Conservada , Deleção de Genes , Filogenia , Homologia de Sequência
11.
Infect Control Hosp Epidemiol ; 33(5): 487-94, 2012 May.
Artigo em Inglês | MEDLINE | ID: mdl-22476275

RESUMO

OBJECTIVE: The objective of this study was to quantify the effectiveness of selected surgical masks in arresting vegetative cells and endospores in an experimental model that simulated contagious patients. SETTING: Laboratory. METHODS: Five commercially available surgical masks were tested for their ability to arrest infectious agents. Surgical masks were placed over the nose and mouth of mannequin head forms (Simulaids adult model Brad CPR torso). The mannequins were retrofitted with a nebulizer attached to an automated breathing simulator calibrated to a tidal volume of 500 mL/breath and a breathing rate of 20 breaths/min, for a minute respiratory volume of 10 L/min. Aerosols of endospores or vegetative cells were generated with a modified microbiological research establishment-type 6-jet collision nebulizer, while air samples were taken with all-glass impinger (AGI-30) samplers downstream of the point source. All experiments were conducted in a horizontal bioaerosol chamber. RESULTS: Mean arrestance of bioaerosols by the surgical masks ranged from 48% to 68% when the masks were challenged with endospores and from 66% to 76% when they were challenged with vegetative cells. When the arrestance of endospores was evaluated, statistical differences were observed between some pairs, though not all, of the models evaluated. There were no statistically significant differences in arrestance observed between models of surgical masks challenged with vegetative cells. CONCLUSIONS: The arrestance of airborne vegetative cells and endospores by surgical masks worn by simulated contagious patients supports surgical mask use as one of the recommended cough etiquette interventions to limit the transmission of airborne infectious agents.


Assuntos
Controle de Doenças Transmissíveis/métodos , Bactérias Formadoras de Endosporo , Manequins , Máscaras/normas , Roupa de Proteção/normas , Laboratórios , Estados Unidos
12.
J Appl Microbiol ; 112(1): 65-78, 2012 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-21985154

RESUMO

AIMS: Despite the frequent isolation of endospore-formers from marine sponges, little is known about the diversity and characterization of individual isolates. The main aims of this study were to isolate and characterize the spore-forming bacteria from the marine sponge Haliclona simulans and to examine their potential as a source for bioactive compounds. METHODS AND RESULTS: A bank of presumptive aerobic spore-forming bacteria was isolated from the marine sponge H. simulans. These represented c. 1% of the total culturable bacterial population. A subgroup of thirty isolates was characterized using morphological, phenotypical and phylogenetic analysis. A large diversity of endospore-forming bacteria was present, with the thirty isolates being distributed through a variety of Bacillus and Paenibacillus species. These included ubiquitous species, such as B. subtilis, B. pumilus, B. licheniformis and B. cereus group, as well as species that are typically associated with marine habitats, such as B. aquimaris, B. algicola and B. hwajinpoensis. Two strains carried the aiiA gene that encodes a lactonase known to be able to disrupt quorum-sensing mechanisms, and various isolates demonstrated protease activity and antimicrobial activity against different pathogenic indicator strains, including Clostridium perfringens, Bacillus cereus and Listeria monocytogenes. CONCLUSIONS: The marine sponge H. simulans harbours a diverse collection of endospore-forming bacteria, which produce proteases and antibiotics. This diversity appears to be overlooked by culture-dependent and culture-independent methods that do not specifically target sporeformers. SIGNIFICANCE AND IMPACT OF STUDY: Marine sponges are an as yet largely untapped and poorly understood source of endospore-forming bacterial diversity with potential biotechnological, biopharmaceutical and probiotic applications. These results also indicate the importance of combining different methodologies for the comprehensive characterization of complex microbial populations such as those found in marine sponges.


Assuntos
Biodiversidade , Bactérias Formadoras de Endosporo/fisiologia , Haliclona/microbiologia , Animais , Anti-Infecciosos/metabolismo , Anti-Infecciosos/farmacologia , Bactérias Formadoras de Endosporo/classificação , Bactérias Formadoras de Endosporo/efeitos dos fármacos , Bactérias Formadoras de Endosporo/genética , Bactérias Formadoras de Endosporo/isolamento & purificação , Bactérias Gram-Negativas/efeitos dos fármacos , Dados de Sequência Molecular , Filogenia , RNA Ribossômico 16S/genética
13.
Folia Microbiol (Praha) ; 55(1): 39-46, 2010 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-20336503

RESUMO

The impact of transgenic white poplars (Populus alba L. cv. 'Villafranca') was assessed on the soil aerobic spore-forming bacteria (SFB). The genetically modified poplars, expressing either the StSy gene for resveratrol production or the bar gene for herbicide tolerance, were cultivated in greenhouse. The occurrence of SFB was monitored in soil samples collected at eight different timepoints over a two-year period. The total culturable bacterial population of the StSy and bar trials underwent significant seasonal fluctuations in the range of 10(6)-2.5 x 10(8) CFU/g dry soil and of 10(4)-5 x 10(8) CFU/g dry soil, respectively. Changes occurred also within the culturable SFB population with size varying at 10(3)-5 x 10(4) CFU/g dry soil and 10(2)-2 x 10(5) CFU/g dry soil in the StSy and bar trials, respectively. No significant differences in the size of the total and SFB culturable populations were observed when comparing each transgenic line with the nontransformed control line while seasonal shifts of soil bacterial populations were evident in both trials. The culturable SFB fraction included three isolates (SFB-1, SFB-2 and SFB-3) classified by 16S rDNA sequence analysis as members of the Bacillus genus. According to the reported data, cultivation of both herbicide-resistant and resveratrol-producing GM white poplars did not affect the culturable SFB population at the soil level.


Assuntos
Bactérias Formadoras de Endosporo/classificação , Bactérias Formadoras de Endosporo/isolamento & purificação , Plantas Geneticamente Modificadas/microbiologia , Populus/microbiologia , Microbiologia do Solo , Aerobiose , Análise por Conglomerados , Contagem de Colônia Microbiana , DNA Bacteriano/química , DNA Bacteriano/genética , DNA Ribossômico/química , DNA Ribossômico/genética , Bactérias Formadoras de Endosporo/fisiologia , Dados de Sequência Molecular , Filogenia , RNA Ribossômico 16S/genética , Estações do Ano , Análise de Sequência de DNA
14.
Biotechnol Bioeng ; 104(5): 1012-24, 2009 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-19572315

RESUMO

We develop a mechanistic life-cycle model for endospore-forming bacteria (EFB) and test the model with experiments with a Bacillus mixed culture. The model integrates and quantifies how sporulation and germination are triggered by depletion or presence of a limiting substrate, while both substrates affect the rate of vegetative growth by a multiplicative model. Kinetic experiments show the accumulation of small spherical spores after the triggering substrate is depleted, substantially more rapid decay during sporulation than for normal decay of vegetative cells, and a higher specific substrate utilization rate for the germinating cells than that for growth of vegetative cells. Model simulations capture all of these experimental trends. According to model predictions, when a batch reactor is started, seeding with EFB spores instead of active EFB delays the onset of rapid chemical oxygen demand (COD) utilization and biomass growth, but the end points are the same. Simulated results with low aeration intensity show that germination can consume some substrate without dissolved oxygen (DO) depletion.


Assuntos
Reatores Biológicos/microbiologia , Bactérias Formadoras de Endosporo/fisiologia , Modelos Biológicos , Esporos Bacterianos/crescimento & desenvolvimento , Aerobiose , Biomassa , Oxigênio/metabolismo
15.
Int J Syst Evol Microbiol ; 59(Pt 8): 2114-21, 2009 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-19567583

RESUMO

Minimal standards for describing new taxa within the aerobic endospore-forming bacteria are proposed, following Recommendation 30b of the Bacteriological Code (1990 Revision). These minimal standards are recommended as guidelines to assist authors in the preparation of descriptions for novel taxa. They encourage broad polyphasic characterization and the construction of descriptions that are practically useful in routine diagnostic laboratories. The proposals have been endorsed by the Subcommittee on the Taxonomy of the Genus Bacillus and Related Organisms of the International Committee on Systematics of Prokaryotes.


Assuntos
Bactérias Formadoras de Endosporo/classificação , Terminologia como Assunto
16.
Wei Sheng Wu Xue Bao ; 49(5): 573-9, 2009 May.
Artigo em Chinês | MEDLINE | ID: mdl-19637562

RESUMO

OBJECTIVE: In order to study the diversity of endophytic endospore-forming bacteria in Cinnamomum longepaniculatum. METHODS: We took modified nutrient agar medium for isolation and cultivation and analyzed the 16S rRNA gene sequences of the isolates. RESULTS: Forty non-redundant endospore-forming bacterial isolates were ascertained, which accounted for 38.1% of all the endophytic bacterial isolates. Of them, 24 isolates were from roots, 7 from stems and 9 from leaves. Phylogenetic analysis based on 16S rRNA gene sequences showed that 35 of them belonged to 16 species of the genera Bacillus, Lysinibacillus and Paenibacillus, and 5 isolates with < 97% sequence similarities to their closely related members were presumed to be potential novel species. CONCLUSION: The results showed that the cultivable endospore-forming bacteria diversity was abundant and there were some potential novel strains in Cinnamomum longepaniculatum. The microflora of endophytic endospore-forming bacteria in individuals of C. longepaniculatum showed that some bacteria distributed in different organs, but the others were organ-specific bacteria.


Assuntos
Cinnamomum/microbiologia , DNA Bacteriano/análise , Bactérias Formadoras de Endosporo/classificação , RNA Ribossômico 16S/análise , Biodiversidade , Bactérias Formadoras de Endosporo/genética , Filogenia , RNA Ribossômico 16S/genética , Análise de Sequência de DNA
17.
Syst Appl Microbiol ; 32(4): 233-44, 2009 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-19217233

RESUMO

Many proteins produced by Bacillus species isolated from extreme environments have been utilized for industrial purposes, as these extreme environments often promote evolution of unique protein properties. The Borax Lake area is unusual due to its geothermal activity, elevated pH, and high arsenic and salt concentrations in its soils. Soils from this region are likely to harbor alkalitolerant, halotolerant, endospore-forming strains that may be of potential ecological and/or commercial interest. The objectives of this study were to develop new PCR primers that could target Bacillus or closely related 16S rRNA genes, to characterize the diversity of alkalitolerant, halotolerant, endospore-forming organisms in the soils surrounding Borax Lake, and to identify novel organisms that may ultimately provide new enzymes for applied use. A three-pronged approach was used to identify such bacteria in soil samples. Organisms were isolated using two different techniques. Finally, metagenomic DNA from soil samples was subjected to 16S rRNA gene amplification using the newly designed primers. Assays were performed to characterize the halotolerance and alkalitolerance of isolates. Four different endospore-forming genera and 22 different species were identified by sequencing their 16S rRNA genes. Twenty-five organisms had 96% or less identity to known organisms. Thus, the newly designed Bacillus-related PCR primer sets proved useful for the detection of new species of endospore-forming bacteria in these unique soils. Results indicate that the collection of strains obtained from the Borax Lake region represents a rich source of alkalitolerant, halotolerant, endospore formers.


Assuntos
Bacillus/classificação , Biodiversidade , Bactérias Formadoras de Endosporo/classificação , Microbiologia do Solo , Álcalis , Bacillus/genética , Bacillus/isolamento & purificação , Bactérias Aeróbias/classificação , Bactérias Aeróbias/genética , Bactérias Aeróbias/isolamento & purificação , Sequência de Bases , Primers do DNA , Bactérias Formadoras de Endosporo/genética , Bactérias Formadoras de Endosporo/isolamento & purificação , Dados de Sequência Molecular , Oregon , Filogenia , RNA Ribossômico 16S/classificação , RNA Ribossômico 16S/genética , Tolerância ao Sal
18.
Mol Microbiol ; 67(6): 1360-70, 2008 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-18284580

RESUMO

The guinea pig intestinal symbiont Metabacterium polyspora is an uncultured, endospore-forming member of the Firmicutes. Unlike most endospore-forming bacteria, sporulation is an obligate part of the M. polyspora life cycle when it is associated with a guinea pig. Binary fission is limited to a brief period in its life cycle, if exhibited at all. Instead, M. polyspora relies on the formation of multiple endospores for reproduction. Sporulation is initiated immediately after germination, which leaves little time for the cell to accumulate resources to support spore formation. Using immunolocalization of the nucleotide analogue bromodeoxyuridine (BrdU), we were able to follow replication dynamics in M. polyspora. BrdU was provided to cells within the guinea pig intestinal tract. BrdU was incorporated into DNA located within the forespores throughout development, at all stages prior to spore maturation. Our results suggest that in M. polyspora, DNA replication within the forespore is not suppressed during sporulation as it is in other endospore-forming bacteria. Replication within forespores would allow M. polyspora to maximize its reproductive potential and supply each endospore with at least one complete copy of the genome.


Assuntos
Replicação do DNA/genética , DNA Bacteriano/genética , Bactérias Formadoras de Endosporo/genética , Animais , Bromodesoxiuridina/química , DNA Bacteriano/química , Bactérias Formadoras de Endosporo/fisiologia , Cobaias , Modelos Biológicos , Esporos Bacterianos/genética , Esporos Bacterianos/fisiologia
19.
Microbiol Immunol ; 51(7): 643-8, 2007.
Artigo em Inglês | MEDLINE | ID: mdl-17641466

RESUMO

We previously reported a new species Paenibacillus motobuensis. The type strain MC10 was stained gram-negative, but had a gram-positive cell wall structure and its spore had a characteristic star shape. The spore and sporulation process of P. motobuensis strain MC10 were examined by electron microscopy using the technique of freeze-substitution in thin sectioning. The structure of the dormant spore was basically the same as that of the other Bacillus spp. The core of the spore was enveloped with two main spore components, the cortex and the spore coat. In thin section, the spore showed a star-shaped image, which was derived from the structure of the spore coat, which is composed of three layers, namely the inner, middle and outer spore coat. The middle coat was an electron-dense thick layer and had a characteristic ridge. By scanning electron microscopic observation, the ridges were seen running parallel to the long axis of the oval-shaped spore. The process of sporulation was essentially the same as that of the other Bacillus spp. The forespore was engulfed by the mother cell membrane, then the spore coat and the cortex were accumulated in the space between the mother cell membrane and forespore membrane. The mother cell membrane seemed to participate in the synthesis of the spore coat. MC10 strain showed almost identical heat resistance to that of B. subtilis.


Assuntos
Bactérias Formadoras de Endosporo/fisiologia , Bactérias Formadoras de Endosporo/ultraestrutura , Bactérias Gram-Negativas/ultraestrutura , Esporos Bacterianos/ultraestrutura , Bacillus subtilis/fisiologia , Bacillus subtilis/ultraestrutura , Bactérias Gram-Negativas/fisiologia , Microscopia Eletrônica de Varredura , Microscopia Eletrônica de Transmissão , Esporos Bacterianos/fisiologia
20.
J Microbiol ; 45(2): 113-21, 2007 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-17483795

RESUMO

The bacterial diversity inherent to the biofilm community structure of a modified rotating biological contactor wastewater treatment process, referred to as the Rotating Activated Bacillus Contactor (RABC) process, was characterized in this study, via both culture-dependent and culture-independent methods. On the basis of culture-dependent methods, Bacillus sp. were found to exist in large numbers on the biofilm (6.5% of the heterotrophic bacteria) and the microbial composition of the biofilms was quite simple. Only three phyla were identified-namely, the Proteobacteria, the Actinobacteria (High G+C Gram-positive bacteria), and the Firmicutes (Low G+C Gram-positive bacteria). The culture-independent partial 16S rDNA sequence analysis revealed a considerably more diverse microbial composition within the biofilms. A total of eight phyla were recovered in this case, three of which were major groups: the Firmicutes (43.9%), the Proteobacteria (28.6%), and the Bacteroidetes (17.6%). The remaining five phyla were minor groups: the Planctomycetes (4.4%), the Chlorobi (2.2%), the Actinobacteria (1.1%), the Nitrospirae (1.1%), and the Verrucomicrobia (1.1%). The two most abundant genera detected were the endospore-forming bacteria (31.8%), Clostridium and Bacillus, both of which are members of the Firmicutes phylum. This finding indicates that these endospore-forming bacteria successfully colonized and dominated the RABC process biofilms. Many of the colonies or clones recovered from the biofilms evidenced significantly high homology in the 16S rDNA sequences of bacteria stored in databases associated with advanced wastewater treatment capabilities, including nitrification and denitrification, phosphorus accumulation, the removal of volatile odors, and the removal of chlorohydrocarbons or heavy metals. The microbial community structures observed in the biofilms were found to correlate nicely with the enhanced performance of advanced wastewater treatment protocols.


Assuntos
Bacillus/crescimento & desenvolvimento , Biofilmes/crescimento & desenvolvimento , Bactérias Formadoras de Endosporo/crescimento & desenvolvimento , Esgotos/microbiologia , Actinobacteria/classificação , Actinobacteria/genética , Actinobacteria/crescimento & desenvolvimento , Bacillus/genética , DNA Bacteriano/química , DNA Bacteriano/genética , Bactérias Formadoras de Endosporo/classificação , Bactérias Formadoras de Endosporo/genética , Dados de Sequência Molecular , Filogenia , Proteobactérias/classificação , Proteobactérias/genética , Proteobactérias/crescimento & desenvolvimento , RNA Ribossômico 16S/genética , Análise de Sequência de DNA , Eliminação de Resíduos Líquidos
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