Showing papers on "Bacillus isolates published in 2005"
TL;DR: Together, the results suggest that some of the sporeformers isolated in this study have the potential to persist in or transiently associate with the complex gut ecosystem.
Abstract: Spores from a number of different Bacillus species are currently being used as human and animal probiotics, although their mechanisms of action remain poorly understood. Here we describe the isolation of 237 presumptive gut-associated Bacillus spp. isolates that were obtained by heat and ethanol treatment of fecal material from organically reared broilers followed by aerobic plating. Thirty-one representative isolates were characterized according to their morphological, physiological, and biochemical properties as well as partial 16S rRNA gene sequences and screening for the presence of plasmid DNA. The Bacillus species identified included B. subtilis, B. pumilus, B. licheniformis, B. clausii, B. megaterium, B. firmus, and species of the B. cereus group, whereas a number of our isolates could not be classified. Intrinsic properties of potential importance for survival in the gut that could be advantageous for spore-forming probiotics were further investigated for seven isolates belonging to five different species. All isolates sporulated efficiently in the laboratory, and the resulting spores were tolerant to simulated gastrointestinal tract conditions. They also exhibited antimicrobial activity against a broad spectrum of bacteria, including food spoilage and pathogenic organisms such as Bacillus spp., Clostridium perfringens, Staphylococcus aureus, and Listeria monocytogenes. Importantly, the isolates were susceptible to most of the antibiotics tested, arguing that they would not act as donors for resistance determinants if introduced in the form of probiotic preparations. Together, our results suggest that some of the sporeformers isolated in this study have the potential to persist in or transiently associate with the complex gut ecosystem.
431 citations
TL;DR: The correlation observed between antimicrobial and hemolytic activities indicated that lipopeptides were involved in the antibiosis mechanism of the studied antagonists, and production of bioactive and surfactant compounds was observed during the late growth phase of the Bacillus isolates.
Abstract: The antagonism of eight Bacillus isolates was investigated against nine strains of Xanthomonas campestris pv. campestris (causal agent of crucifers black rot) to assess the role of lipopeptides in this process. Antimicrobial and hemolytic (surfactant) activity tests were performed in vitro using agar diffusion methods. Antibiosis and hemolysis were positive for four Bacillus isolates against all X. campestris pv. campestris strains. The correlation observed between antimicrobial and hemolytic activities indicated that lipopeptides were involved in the antibiosis mechanism of the studied antagonists. Fermentation studies were carried out with the isolates that showed highest antimicrobial and hemolytic activities, to follow up growth and production of bioactive and surfactant compounds. Production of bioactive and surfactant compounds was observed during the late growth phase of the Bacillus isolates.
93 citations
TL;DR: Twenty isolates of fluorescent pseudomonads and Bacillus spp.
Abstract: Twenty isolates of fluorescent pseudomonads and Bacillus spp. were obtained from pathogen suppressive soil of a pigeonpea (Cajanus cajan) field showing wilt disease complex. These isolates were evaluated in the laboratory and screen-house for the biocontrol of wilt disease complex. Six isolates were considered to have potential for the biocontrol of the disease on the basis of antibiotic sensitivity, antifungal activity, fluorescence produced by Pseudomonas, inhibitory effect on the hatching and penetration of nematodes and colonization of pigeonpea roots by these isolates. These isolates will be further tested for their biocontrol of wilt disease complex of pigeonpea under field conditions.
59 citations
Journal Article•
TL;DR: To validate an assay for B. anthracis detection, it is critical to examine its specificity with the most closely related Bacillus isolates that are available, and the inclusion of the 19 ST isolates will prove to be useful for screening for their specificity to detect B. Anthracis.
Abstract: There have been many efforts to develop Bacillus anthracis detection assays, but the problem of false-positive results has often been encountered. Therefore, to validate an assay for B. anthracis detection, it is critical to examine its specificity with the most closely related Bacillus isolates that are available. To define the most closely related Bacillus isolates to B. anthracis in our Bacillus collections, we analyzed by multilocus sequence typing (MLST) the phylogeny of 77 closely related Bacillus isolates selected from 264 Bacillus isolates. The selection includes all the Bacillus isolates that have been shown in our previous studies to produce false-positive results by some anthrax-detection assays. The MLST phylogenetic analyses revealed that 27 of the non-B. anthracis isolates clustered within the B. anthracis clade, and four of them (three sequence types, STs) had the highest degree of genetic relatedness with B. anthracis, 18 (11 STs) had the second highest, and five (five STs) had the third highest. We anticipate that the inclusion of the 19 ST isolates when analyzing B. anthracis detection assays will prove to be useful for screening for their specificity to detect B. anthracis.
16 citations
TL;DR: Results showed that the classical phenotypic tests allowed the reclassification of the isolates, while modern techniques of chemotaxonomy and the molecular approach led only to genus and cluster classification and confirmation.
Abstract: The taxonomy of 58 locally isolated antibiotic- and enzyme-producing Bacillus isolates deposited at the Philippine National Collection of Microorganisms (PNCM)-BIOTECH was reassessed in this study using a polyphasic approach since they had been only partially identified prior to deposition in the culture collection. The isolates had 41.1–69% G + C, and possessed the characteristic diaminopimelic acid (DAP) and fatty acid methyl ester (FAMEs) properties of Bacillus species. Molecular analysis using specific PCR primers differentiated the isolates into two major groups, the Bacillus cereus group and the Bacillus subtilis group. To further differentiate these isolates, they were subjected to 39 phenotypic tests. Using the dichotomous key constructed for Bacillus, 45 isolates maintained their original identities, five were named at the species level, and 12 were re-identified and renamed. These results showed that the classical phenotypic tests allowed the reclassification of the isolates, while modern techniques of chemotaxonomy and the molecular approach led only to genus and cluster classification and confirmation.
12 citations
TL;DR: Four novel ellipsoidal spore-forming Bacillus isolates with swollen sporangia, isolated from raw milk and feed concentrate, showed a high level of similarity in SDS-PAGE, fatty acid methyl esters and routine phenotypic tests, but 16S rRNA gene sequence comparisons showed that this taxon was different from other related Bacillus species.
Abstract: Four novel ellipsoidal spore-forming Bacillus isolates with swollen sporangia, isolated from raw milk and feed concentrate, showed a high level of similarity in SDS-PAGE, fatty acid methyl esters and routine phenotypic tests. However, 16S rRNA gene sequence comparisons showed that this taxon was different from other related Bacillus species, and only a low level of DNA relatedness was found with the closest phylogenetic and phenotypic relative, Bacillus galactosidilyticus. This taxon could be differentiated from B. galactosidilyticus on the basis of morphological differences, stronger acid reactions with a wide range of substrates after 48 h incubation, and qualitative and quantitative differences in fatty acid content. On the basis of these data, a novel species, Bacillus ruris sp. nov., is proposed, with LMG 22866T (=DSM 17057T) as the type strain.
11 citations
Journal Article•
TL;DR: The research showed that extracellular protein profiles obtained by SDS-PAGE provide an effective approach to the investigation of taxonomic relationships within native alkaliphilic Bacillus isolates and other Bacillus species.
Abstract: Five reference Bacillus species and 17 native alkaliphilic Bacillus strains, isolated from the water of Lake Van and the soil surrounding it, were identified using phenotypic characteristics and extracellular protein profiles by the method of sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). According to the phenotypic characteristics, all the native isolates were Gram-positive, aerobic, endospore-forming, motile, facultatively alkaliphilic Bacillus spp. It was also found that the native alkaliphilic Bacillus isolates were distinguished phenotypically from other Bacillus species. A numerical analysis based on the resulting extracellular protein profiles revealed 5 distinct clusters: native isolates and B. megaterium formed 4 clusters that varied between 69% and 100% similarity, and the other reference Bacillus species formed a cluster with a similarity of above 70%. The research showed that extracellular protein profiles obtained by SDS-PAGE provide an effective approach to the investigation of taxonomic relationships within native alkaliphilic Bacillus isolates and other Bacillus species.
8 citations
1 Jan 2005
TL;DR: The research showed that extracellular protein profiles obtained by SDS-PAGE provide an effective approach to the investigation of taxonomic relationships within native alkaliphilic Bacillus isolates and other Bacillus species.
Abstract: Five reference Bacillus species and 17 native alkaliphilic Bacillus strains, isolated from the water of Lake Van and the soil surrounding it, were identified using phenotypic characteristics and extracellular protein profiles by the method of sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). According to the phenotypic characteristics, all the native isolates were Gram-positive, aerobic, endospore-forming, motile, facultatively alkaliphilic Bacillus spp. It was also found that the native alkaliphilic Bacillus isolates were distinguished phenotypically from other Bacillus species. A numerical analysis based on the resulting extracellular protein profiles revealed 5 distinct clusters: native isolates and B. megaterium formed 4 clusters that varied between 69% and 100% similarity, and the other reference Bacillus species formed a cluster with a similarity of above 70%. The research showed that extracellular protein profiles obtained by SDS-PAGE provide an effective approach to the investigation of taxonomic relationships within native alkaliphilic Bacillus isolates and other Bacillus species.
6 citations