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Bioscience Trends Jan 2020Bacillus cereus (B. cereus) and Staphylococcus aureus (S. aureus) are major human food-borne pathogens that may produce a variety of toxins and cause diarrhea, food...
Bacillus cereus (B. cereus) and Staphylococcus aureus (S. aureus) are major human food-borne pathogens that may produce a variety of toxins and cause diarrhea, food poisoning, and even death. In order to monitor and prevent the spread of these pathogens, a multiplex loop-mediated isothermal amplification (multi-LAMP) assay was developed to simultaneously and rapidly detect B. cereus and S. aureus. The sensitivity and specificity of the loop-mediated isothermal amplification (LAMP) reactions were determined via electrophoresis. The multi-LAMP showed 100% inclusivity and exclusivity, the sensitivity was 10 fg/μL and was 10 times more sensitive than that of polymerase chain reaction (PCR), the results were consistent with those of conventional PCR assay, and the entire assay should be finished within 40 min. This multi-LAMP assay was confirmed as a rapid and reliable diagnostic technique upon application for clinical samples and food samples. To our knowledge, this is the first study to report the application of multi-LAMP to detect B. cereus and S. aureus.
Topics: Bacillus cereus; Electrophoresis; Nucleic Acid Amplification Techniques; Polymerase Chain Reaction; Staphylococcal Infections; Staphylococcus aureus
PubMed: 31852862
DOI: 10.5582/bst.2019.01267 -
Applied and Environmental Microbiology Jan 2001Many strains of Bacillus cereus cause gastrointestinal diseases, and the closely related insect pathogen B. thuringiensis has also been involved in outbreaks of...
Many strains of Bacillus cereus cause gastrointestinal diseases, and the closely related insect pathogen B. thuringiensis has also been involved in outbreaks of diarrhea. The diarrheal types of diseases are attributed to enterotoxins. Two different enterotoxic protein complexes, hemolysin BL (HBL) and nonhemolytic enterotoxin (NHE), and an enterotoxic protein, enterotoxin T, have been characterized, and the genes have been sequenced. PCR primers for the detection of these genes were deduced and used to detect the genes in 22 B. cereus and 41 B. thuringiensis strains. At least one gene of each of the two protein complexes HBL and NHE was detected in all of the B. thuringiensis strains, while six B. cereus strains were devoid of all three HBL genes, three lacked at least two of the three NHE genes, and one lacked all three. Five different sets of primers were used for detection of the gene (bceT) encoding enterotoxin T. The results obtained with these primer sets indicate that bceT is widely distributed among B. cereus and B. thuringiensis strains and that the gene varies in sequence among different strains. PCR with the two primer sets BCET1-BCET3 and BCET1-BCET4 unambiguously detected the bceT gene, as confirmed by Southern analysis. The occurrence of the genes within the two complexes is significantly associated, while neither the occurrence of the two complexes nor the occurrence of the bceT gene is significantly associated in the 63 strains. We suggest an approach for detection of enterotoxin-encoding genes in B. cereus and B. thuringiensis based on PCR analysis with the six primer sets for the detection of genes in the HBL and NHE operons and with the BCET1, BCET3, and BCET4 primers for the detection of bceT. PCR analysis of the 16S-23S rRNA gene internal transcribed spacer region revealed identical patterns for all strains studied.
Topics: Bacillus cereus; Bacillus thuringiensis; Bacterial Proteins; Blotting, Southern; DNA, Bacterial; Diarrhea; Enterotoxins; Gram-Positive Bacterial Infections; Hemolysin Proteins; Humans; Polymerase Chain Reaction
PubMed: 11133444
DOI: 10.1128/AEM.67.1.185-189.2001 -
PloS One 2019The bacterial strain WD-2, which was capable of efficiently degrading prochloraz-manganese, was isolated from soil contaminated with prochloraz-manganese, selected...
The bacterial strain WD-2, which was capable of efficiently degrading prochloraz-manganese, was isolated from soil contaminated with prochloraz-manganese, selected through enrichment culturing and identified as Bacillus cereus. Test results indicated that the optimal temperature and pH for bacterial growth were 35-40°C and 7.0-8.0, respectively. The highest degradation rate was above 88-90% when the pH was 7.0~8.0 and reached a maximum value (90.7%) at approximately 8.0. In addition, the bacterium showed the greatest growth ability with an OD600 of 0.805 and the highest degradation rate (68.2%) when glucose was chosen as the carbon source, while the difference in nitrogen source had no obvious influence on bacterial growth. The degradation rate exceeded 80% when the NaCl concentration was 0~2% and the rate reached 89.2% at 1%. When the concentration was higher than 7%, the growth of WD-2 and the degradation of prochloraz-manganese were found to be inhibited, and the degradation rate was merely 8.5%. The results indicated that strain WD-2 was able to effectively degrade prochloraz-manganese and might contribute to the bioremediation of contaminated soils.
Topics: Bacillus cereus; Biodegradation, Environmental; Carbon; Hydrogen-Ion Concentration; Imidazoles; Kinetics; Manganese; Nitrogen; Phylogeny; RNA, Ribosomal, 16S; Salinity; Soil Microbiology; Soil Pollutants; Temperature
PubMed: 31398235
DOI: 10.1371/journal.pone.0220975 -
Current Microbiology Jul 2016Proanthocyanidins are abundant in peanut skin, and in this study, the antibacterial effects of a peanut skin extract (PSE) against food-borne bacteria were investigated...
Proanthocyanidins are abundant in peanut skin, and in this study, the antibacterial effects of a peanut skin extract (PSE) against food-borne bacteria were investigated to find its minimum inhibitory concentration. Food-borne gram-positive bacteria, and in particular Bacillus cereus, was more sensitive to PSE. In particular, the inhibitory activity of epicatechin-(4β → 6)-epicatechin-(2β → O→7, 4β → 8)-catechin (EEC), a proanthocyanidin trimer from peanut skin, against B. cereus was stronger than that of procyanidin A1, a proanthocyanidin dimer. DNA microarray analysis of B. cereus treated with EEC was carried out, with a finding that 597 genes were significantly up-regulated. Analysis of the up-regulated genes suggested that EEC disrupted the normal condition of the cell membrane and wall of B. cereus and alter its usual nutritional metabolism. Moreover, treatment of B. cereus with EEC inhibited glucose uptake, suggesting that EEC affects the cell-surface adsorption.
Topics: Anti-Bacterial Agents; Arachis; Bacillus cereus; Bacterial Proteins; Gene Expression Regulation, Bacterial; Molecular Structure; Plant Extracts; Proanthocyanidins; Transcription, Genetic
PubMed: 27061585
DOI: 10.1007/s00284-016-1032-x -
Journal of Applied Microbiology Sep 2017LI-Fs are a family of highly potent cyclic lipodepsipeptide antibiotics with a broad antimicrobial spectrum (Gram-positive bacteria and fungi). In this study, LI-F-type...
AIMS
LI-Fs are a family of highly potent cyclic lipodepsipeptide antibiotics with a broad antimicrobial spectrum (Gram-positive bacteria and fungi). In this study, LI-F-type antimicrobial peptides (AMP-jsa9) composing of LI-F03a, LI-F03b, LI-F04a, LI-F04b and LI-F05b were isolated from Paenibacillus polymyxa JSA-9. To better understand the antimicrobial mechanism of AMP-jsa9, the potency and action(s) of AMP-jsa9 against Bacillus cereus were examined.
METHODS AND RESULTS
Flow cytometry, confocal laser microscopy, scanning electron microscopy, transmission electron microscopy (TEM) and atomic force microscopy observation, as well as determination of peptidoglycan and cell wall-associated protein and other methods were used. The results indicate that AMP-jsa9 exhibits strong, broad-spectrum antimicrobial activity. Moreover, AMP-jsa9 targets the cell wall and membrane of B. cereus to impair membrane integrity, increase membrane permeability and enhance cytoplasm leakage (e.g. K , protein, nucleic acid). This leads to bacterial cells with irregular, withered and coarse surfaces. In addition, AMP-jsa9 is also able to bind to DNA and break down B. cereus biofilms.
CONCLUSIONS
In this study, the action mechanism of LI-Fs against B. cereus was clarified in details.
SIGNIFICANCE AND IMPACT OF THE STUDY
The results of this study provide a theoretical basis for utilizing AMP-jsa9 or similar analogues as natural and effective preservatives in the food and feed industries. These efforts could also stimulate research activities interested in understanding the specific effects of other antimicrobial agents.
Topics: Anti-Bacterial Agents; Bacillus cereus; Bacterial Proteins; Depsipeptides; Enkephalin, Methionine; Paenibacillus polymyxa; Protein Precursors
PubMed: 28650559
DOI: 10.1111/jam.13526 -
MBio Aug 2020Cereulide-producing members of group III (also known as emetic ) possess cereulide synthetase, a plasmid-encoded, nonribosomal peptide synthetase encoded by the gene...
Cereulide-producing members of group III (also known as emetic ) possess cereulide synthetase, a plasmid-encoded, nonribosomal peptide synthetase encoded by the gene cluster. Despite the documented risks that cereulide-producing strains pose to public health, the level of genomic diversity encompassed by emetic has never been evaluated at a whole-genome scale. Here, we employ a phylogenomic approach to characterize group III genomes which possess ( positive) alongside their closely related, -negative counterparts (i) to assess the genomic diversity encompassed by emetic and (ii) to identify potential loss and/or gain events within the evolutionary history of the high-risk and medically relevant sequence type (ST) 26 lineage often associated with emetic foodborne illness. Using all publicly available -positive group III genomes and the -negative genomes interspersed among them ( = 159), we show that emetic is not clonal; rather, multiple lineages within group III harbor cereulide-producing strains, all of which share an ancestor incapable of producing cereulide (posterior probability = 0.86 to 0.89). Members of ST 26 share an ancestor that existed circa 1748 (95% highest posterior density [HPD] interval = 1246.89 to 1915.64) and first acquired the ability to produce cereulide before 1876 (95% HPD = 1641.43 to 1946.70). Within ST 26 alone, two subsequent gain events were observed, as well as three loss events, including among isolates responsible for toxicoinfection (i.e., "diarrheal" illness). is responsible for thousands of cases of foodborne disease each year worldwide, causing two distinct forms of illness: (i) intoxication via cereulide (i.e., emetic syndrome) or (ii) toxicoinfection via multiple enterotoxins (i.e., diarrheal syndrome). Here, we show that emetic is not a clonal, homogenous unit that resulted from a single cereulide synthetase gain event followed by subsequent proliferation; rather, cereulide synthetase acquisition and loss is a dynamic, ongoing process that occurs across lineages, allowing some group III populations to oscillate between diarrheal and emetic foodborne pathogens over the course of their evolutionary histories. We also highlight the care that must be taken when selecting a reference genome for whole-genome sequencing-based investigation of emetic outbreaks, since some reference genome selections can lead to a confounding loss of resolution and potentially hinder epidemiological investigations.
Topics: Bacillus cereus; Depsipeptides; Diarrhea; Emetics; Food Microbiology; Foodborne Diseases; Genome, Bacterial; Humans; Multigene Family; Peptide Synthases; Phylogeny
PubMed: 32843545
DOI: 10.1128/mBio.01263-20 -
Scientific Reports Nov 2018Some Bacillus strains function as predominant plant-growth-promoting rhizobacteria. Bacillus cereus 905 is a rod-shaped Gram-positive bacterium isolated from wheat... (Comparative Study)
Comparative Study
Some Bacillus strains function as predominant plant-growth-promoting rhizobacteria. Bacillus cereus 905 is a rod-shaped Gram-positive bacterium isolated from wheat rhizosphere and is a rhizobacterium that exhibits significant plant-growth-promoting effects. Species belonging to the genus Bacillus are observed in numerous different habitats. Several papers on B. cereus are related to pathogens that causes food-borne illness and industrial applications. However, genomic analysis of plant-associated B. cereus has yet to be reported. Here, we conducted a genomic analysis comparing strain 905 with three other B. cereus strains and investigate the genomic characteristics and evolution traits of the species in different niches. The genome sizes of four B. cereus strains range from 5.38 M to 6.40 M, and the number of protein-coding genes varies in the four strains. Comparisons of the four B. cereus strains reveal 3,998 core genes. The function of strain-specific genes are related to carbohydrate, amino acid and coenzyme metabolism and transcription. Analysis of single nucleotide polymorphisms (SNPs) indicates local diversification of the four strains. SNPs are unevenly distributed throughout the four genomes, and function interpretation of regions with high SNP density coincides with the function of strain-specific genes. Detailed analysis indicates that certain SNPs contribute to the formation of strain-specific genes. By contrast, genes related to plant-growth-promoting traits are highly conserved. This study shows the genomic differences between four strains from different niches and provides an in-depth understanding of the genome architecture of these species, thus facilitating genetic engineering and agricultural applications in the future.
Topics: Bacillus cereus; Bacterial Proteins; Genome, Bacterial; Genomics; Phenotype; Phylogeny; Plant Development; Plant Growth Regulators; Plants; Rhizosphere
PubMed: 30451927
DOI: 10.1038/s41598-018-35300-y -
BMC Microbiology Nov 2020Bacillus thuringiensis bacteria share similar genetic, physiological, and biochemical characteristics with other members of the Bacillus cereus group. Their diversity...
Application of Bacillus thuringiensis strains with conjugal and mobilizing capability drives gene transmissibility within Bacillus cereus group populations in confined habitats.
BACKGROUND
Bacillus thuringiensis bacteria share similar genetic, physiological, and biochemical characteristics with other members of the Bacillus cereus group. Their diversity and entomopathogenic origin are related to their mobile genetic elements. However, the effects of wide-spread application of B. thuringiensis-based pesticides on genetically related B. cereus group populations present in the environment remain poorly understood.
RESULTS
We first identified pBMB76 from B. thuringiensis tenebrionis as a new conjugative plasmid. Mixed mating experiments suggested that pBMB76 may compete with pHT73, another known conjugative plasmid. Applications of single (tenebrionis 4AA1 and kurstaki HD73 carrying pBMB76 and pHT73, respectively) and mixed (4AA1 + HD73) B. thuringiensis strains were performed in confined plot habitats (soil and leaf) over two planting seasons. In total, 684 B. cereus group isolates were randomly selected from different treatment sets, and the transmissibility and occurrence rate of potential conjugative plasmids were surveyed. Results showed that the percentage of isolates with plasmid mobility was markedly enhanced in the B. thuringiensis-sprayed groups. Furthermore, we performed multi-locus sequence typing (MLST) for a subset of 291 isolates, which indicated that the dominant sequence types in the treated habitats were identical or related to the corresponding sprayed formulations.
CONCLUSIONS
The application of B. thuringiensis strains with conjugal and mobilizing capability drove gene transmissibility within the B. cereus group populations in confined habitats and potentially modified the population structure.
Topics: Bacillus cereus; Bacillus thuringiensis; Biological Control Agents; Conjugation, Genetic; Ecosystem; Genes, Bacterial; Plant Leaves; Plasmids; Soil Microbiology
PubMed: 33243143
DOI: 10.1186/s12866-020-02047-4 -
PloS One 2016Bacterial collagenases differ considerably in their structure and functions. The collagenases ColH and ColG from Clostridium histolyticum and ColA expressed by...
Bacterial collagenases differ considerably in their structure and functions. The collagenases ColH and ColG from Clostridium histolyticum and ColA expressed by Clostridium perfringens are well-characterized collagenases that cleave triple-helical collagen, which were therefore termed as ´true´ collagenases. ColA from Bacillus cereus (B. cereus) has been added to the collection of true collagenases. However, the molecular characteristics of B. cereus ColA are less understood. In this study, we identified ColA as a secreted true collagenase from B. cereus ATCC 14579, which is transcriptionally controlled by the regulon phospholipase C regulator (PlcR). B. cereus ATCC 14579 ColA was cloned to express recombinant wildtype ColA (ColAwt) and mutated to a proteolytically inactive (ColAE501A) version. Recombinant ColAwt was tested for gelatinolytic and collagenolytic activities and ColAE501A was used for the production of a polyclonal anti-ColA antibody. Comparison of ColAwt activity with homologous proteases in additional strains of B. cereus sensu lato (B. cereus s.l.) and related clostridial collagenases revealed that B. cereus ATCC 14579 ColA is a highly active peptidolytic and collagenolytic protease. These findings could lead to a deeper insight into the function and mechanism of bacterial collagenases which are used in medical and biotechnological applications.
Topics: Amino Acid Sequence; Bacillus cereus; Cloning, Molecular; Collagenases; Genes, Bacterial
PubMed: 27588686
DOI: 10.1371/journal.pone.0162433 -
Applied and Environmental Microbiology Jul 2019Bacterial adaptation is characterized by a lag phase during which cells do not multiply or modify their physiology to cope with the constraints of their environment. Our...
Bacterial adaptation is characterized by a lag phase during which cells do not multiply or modify their physiology to cope with the constraints of their environment. Our aim was to determine a sequence of events during the lag phase of growth at low temperature and pH for three strains. The onsets of expression of two genes, one of which is essential for stress adaptation (, coding for a RNA helicase) and one of which is involved in the transition between lag phase and exponential phase (, coding for a transition regulator), were determined using fluorescent transcriptional reporter systems. Regardless of the stressing conditions and the tested strains, the promoter was active very early, while the biomass increased and always did so before the first cell division. At 12°C and pH 7.0, the onset of promoter activity occurred at between 3 h and 7 h, while the bacterial counts started to increase at between 12 h and 13 h. At pH 5.0 and at 20°C or 30°C, the onset of promoter activity occurred before 1 h and earlier than at pH 7.0. In contrast, the onset of promoter activity depended on the strain and the stressing conditions. In the ATCC 14579 strain, the onset of promoter activity always started at between 30 min and 3 h, before biomass increased and cell division occurred. For the other strains, it took place along with the first cell division at 12°C but did so much later during growth under the other tested conditions. The spore-forming bacterium is a major cause of foodborne outbreaks in Europe. Some strains can grow at low temperatures and low pH in many processed foods. Modeling of the bacterial lag time is hampered by a lack of knowledge of the timing of events occurring during this phase. In this context, the identification of lag phase markers, not currently available, could be a real advance for the better prediction of lag time duration. Currently, no molecular markers of this phase are available. By determining that was always expressed early during the lag phase, we provide a molecular marker of the early adaptation process of cells when exposed to low temperature and pH.
Topics: Adaptation, Physiological; Bacillus cereus; Bacterial Proteins; Cold Temperature; Gene Expression; Genetic Markers; Hydrogen-Ion Concentration; Membrane Proteins
PubMed: 31076436
DOI: 10.1128/AEM.00486-19