1,721,002 research outputs found
Flagella, swarming motility, and virulence in Bacillus cereus and Bacillus thuringiensis
No full text
Rapid determination of vitamin B2 secretion by bacteria growing on solid media
No full textAims: Development of an agar‐diffusion assay to measure vitamin B2 in biological samples and application of the method to determine the amount of vitamin B2 secreted by bacteria.
Methods and Results: A riboflavin‐auxotrophic mutant of Bacillus cereus was generated by mini‐Tn10 insertion in the ribD gene. ribD mutant sensitivity to exogenous vitamin B2 was investigated by turbidimetric and agar‐diffusion assays. In turbidimetric assays, the B. cereus mutant displayed a similar level of sensitivity to vitamin B2 to that of Lactobacillus casei ATCC 7469, the reference organism used for microbiological vitamin B2 quantification. However, only the ribD mutant could be used as an indicator organism in agar‐diffusion assays. A total of eight probiotic strains, from five different probiotic formulations, were analysed by the ribD mutant‐based assay on agar plates in order to determine their ability to secrete vitamin B2 during growth.
Conclusion: The agar diffusion method with the ribD mutant of B. cereus is highly reproducible, sensitive, rapid, inexpensive, and can be applied to measure the amount of vitamin B2 in different samples.
Significance and Impact of the Study: The method developed in this study appears to be a good candidate for the screening of vitamin B2 secretion by bacteria growing on solid media
FLHF IS INVOLVED IN THE REGULATION OF FLAGELLAR NUMBER, SWARM-CELL DIFFERENTIATION, AND SECRETION IN BACILLUS CEREUS
No full textIDENTIFICATION OF GENES REQUIRED FOR SWARM-CELL DIFFERENTIATION IN BACILLUS CEREUS/BACILLUS THURINGIENSIS
No full textToxins of bacillus cereus. [Bacillus cereus e le sue tossine]
No full textBacillus cereus is the causative agent of both gastrointestinal and non-gastrointestinal infections. Enterotoxins, emetic toxin (cereulide), hemolysins, cytotoxin K, and phospholipases are known as potential virulence factors of this microorganism. The epidemiology and pathogenesis of B. cereus-caused diseases in man as well as the toxins produced by this organism are briefly reviewed in this report. Particular attention has been given to the methods that allow for the evaluation of the toxigenic profile and pathogenic potential of B. cereus strains
Involvement of flhF in the regulation of flagellar number, swarm cell differentiation, and secretion in Bacillus cereus
No full textFactors influencing virulence and opportunistic properties of Bacillus cereus and Bacillus thuringiensis
No full textSpotlight on the Compositional Quality of Probiotic Formulations Marketed Worldwide
Full text linkOn the worldwide market, a great number of probiotic formulations are available to consumers as drugs, dietary supplements, and functional foods. For exerting their beneficial effects on host health, these preparations should contain a sufficient amount of the indicated living microbes and be pathogen-free to be safe. Therefore, the contained microbial species and their amount until product expiry are required to be accurately reported on the labels. While commercial formulations licensed as drugs are subjected to rigorous quality controls, less stringent regulations are generally applied to preparations categorized as dietary supplements and functional foods. Many reports indicated that the content of several probiotic formulations does not always correspond to the label claims in terms of microbial identification, number of living organisms, and purity, highlighting the requirement for more stringent quality controls by manufacturers. The main focus of this review is to provide an in-depth overview of the microbiological quality of probiotic formulations commercialized worldwide. Many incongruences in the compositional quality of some probiotic formulations available on the worldwide market were highlighted. Even if manufacturers carry at least some of the responsibility for these inconsistencies, studies that analyze probiotic products should be conducted following recommended and up-to-date methodologies
- …
