Transcriptome analysis of Bacillus thuringiensis spore life, germination and cell outgrowth in a vegetable-based food model.

Transcriptome analysis of Bacillus thuringiensis spore life, germination and cell outgrowth in a vegetable-based food model. Food Microbiol. 2016 May;55:73-85 Authors: Bassi D, Colla F, Gazzola S, Puglisi E, Delledonne M, Cocconcelli PS Abstract Toxigenic species belonging to Bacillus cereus sensu lato, including Bacillus thuringiensis, cause foodborne outbreaks thanks to their capacity to survive as spores and to grow in food matrixes. The goal of this work was to assess by means of a genome-wide transcriptional assay, in the food isolate B. thuringiensis UC10070, the gene expression behind the process of spore germination and consequent outgrowth in a vegetable-based food model. Scanning electron microscopy and Energy Dispersive X-ray microanalysis were applied to select the key steps of B. thuringiensis UC10070 cell cycle to be analyzed with DNA-microarrays. At only 40 min from heat activation, germination started rapidly and in less than two hours spores transformed in active growing cells. A total of 1646 genes were found to be differentially expressed and modulated during the entire B. cereus life cycle in the food model, with most of the significant genes belonging to transport, transcriptional regulation and protein synthesis, cell wall and motility and DNA repair groups. Gene expression studies revealed that toxin-coding genes nheC, cytK and hblC were found to be expressed in vegetative cells growing in the food model. PMID: ...
Source: Food Microbiology - Category: Food Science Authors: Tags: Food Microbiol Source Type: research

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z M Abstract Cereulide, a potent toxin produced by Bacillus cereus, is a small, highly heat- and acid-resistant depsipeptide toxin, which confronts food industry with several challenges. Due to the ubiquitous presence of B. cereus in the environment, this opportunistic pathogen can enter food production and processing at almost any stage. Although the bacteria itself might be removed during food processing, the cereulide toxin will most likely not be destroyed or inactivated by these processes. Because of the high toxicity of cereulide and the high incidence rates often observed in connection with foodborne outbre...
Source: Food Microbiology - Category: Food Science Authors: Tags: Food Microbiol Source Type: research
ConclusionsBacillus cereus is responsible for two types of food poisoning, diarrhoeal (an infection) and emetic (an intoxication); however, no reported outbreaks of food poisoning have been associated with B. cereus and correctly stored commercially-produced minimally processed chilled foods. In the UK alone, more than 1010 packs of these foods have been sold in recent years without reported illness, thus the risk presented is very low. Further quantification of the risk is merited, and this requires additional data. The lack of association between diarrhoeal food poisoning and correctly stored commercially-produced minima...
Source: Trends in Food Science and Technology - Category: Food Science Source Type: research
This study aimed to assess, by molecular studies, the virulent nature of some Bacillus strains in live edible snails (Achatina achatina) sold in Nigerian markets and to ascertain the survival of bacilli during culinary preparation. Results showed that isolates with high virulence potentials were B. thuringiensis and two strains of B. cereus (GenBank accession numbers: MK530172, MK530171 and MK530202). The nheb gene was detected in all three isolates, while B. thuringiensis strain was found to possess hbla, nhea, nheb and cytk genes for enterotoxins often implicated in diarrhoea cases. Most isolates were resistant to chlora...
Source: Food Control - Category: Food Science Source Type: research
Abstract Fresh vegetables are important components of an everyday balanced diet making ready to-eat-salads (RTE) a commodity widely consumed. However, in the past few years these products have been linked with outbreaks of salmonellosis and listeriosis; thus the continuous investigation of their safety is an essential requirement. A total of 216 samples of ready-to-eat salads from the Cypriot market were analysed to determine the microbiological quality and safety, along with physicochemical attributes of the salads and identify possible correlations between them. The samples were randomly collected from four reta...
Source: Food Microbiology - Category: Food Science Authors: Tags: Food Microbiol Source Type: research
CONCLUSIONSThis investigation found that a breach in infection control took place, specifically associated with improper aseptic technique, inadequate disinfection and sterilization of equipment, batch compounding, and environmental cleaning. Because the jet injector was consistently cleaned with tap water, the cultured organisms support the possibility of an infection control breach, namely Mycobacterium chelonae.
Source: American Journal of Infection Control - Category: Infectious Diseases Source Type: research
In this study, a transposon mutagenesis approach was applied to reveal the factors involved in resistance to oxidative stress, and the biofilm formation among mutants and WT strains were further detected using crystal violet staining (CVS), scanning electron microscopy (SEM), and confocal laser scanning microscopy (CLSM) to reveal potential relationship between oxidative stress and biofilm formation. Materials and Methods The Development of Mutants Library The procedure of transposon mutagenesis approach was performed as described by Zhang et al. (2018). Screening of Mutants Tolerance to Oxidative Stress For screening...
Source: Frontiers in Microbiology - Category: Microbiology Source Type: research
Conclusion Since B. cereus group are highly similar in biochemical as well as genetic profiles, a new biomarker was developed for identifying and distinguishing B. thuringiensis from the closely related group. The performance of XRE was compared with cry2 gene and artificially contaminated samples were also tested. Compared with cry2, XRE gene was observed to be efficiently accurate in the identification of B. thuringiensis. Further, the developed real-time PCR using XRE successfully identified B. thuringiensis and it could be used to quantify cell numbers with the generated standard curve. Author Contributions The expe...
Source: Frontiers in Microbiology - Category: Microbiology Source Type: research
Murat Bağcıoğlu1,2†, Martina Fricker1†‡, Sophia Johler2 and Monika Ehling-Schulz1* 1Functional Microbiology, Institute of Microbiology, Department of Pathobiology, University of Veterinary Medicine Vienna, Vienna, Austria 2Institute for Food Safety and Hygiene, Vetsuisse Faculty, University of Zurich, Zurich, Switzerland The Bacillus cereus group comprises genetical closely related species with variable toxigenic characteristics. However, detection and differentiation of the B. cereus group species in routine diagnostics can be difficult, expensive and laborious since current species desi...
Source: Frontiers in Microbiology - Category: Microbiology Source Type: research
Conclusion Starter cultures are an important tool that contributes to ensure the safety of fermented meat products. Indeed, the microorganisms that constitute starter cultures may inhibit or reduce the growth of spoilage and/or pathogenic populations through mechanisms, such as production of certain metabolites or competitive exclusion. Thus, the use of starter cultures may reduce the need for chemical additives, such as nitrites and nitrates. Furthermore, the lower residual levels of nitrates and nitrites detected in fermented meat products inoculated with starter cultures are due to the ability of starters to metabolize...
Source: Frontiers in Microbiology - Category: Microbiology Source Type: research
This study provides new insight into the characterization of foodborne C. perfringens and highlights the potential of WGS for the investigation of FBOs. Introduction Clostridium perfringens is a Gram-positive, spore-forming, anaerobic, rod-shaped bacterium, known as an important causative agent of foodborne and non-foodborne gastroenteritis (Grass et al., 2013). The ability of this bacterium to form resistant spores contributes to its survival in many environmental niches, including soil, sewage, foods, and the intestinal microbiota of humans and animals (Xiao, 2014; Li et al., 2016). C. perfringens can cause necro...
Source: Frontiers in Microbiology - Category: Microbiology Source Type: research
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