The megaplasmid pCER270 of emetic strain affects the timing of the sporulation process, spore resistance properties, and germination.

Unlabelled: The group includes closely related spore-forming Gram-positive bacteria. In this group, plasmids play a crucial role in species differentiation and are essential for pathogenesis and adaptation to ecological niches. The emetic strains are characterized by the presence of the pCER270 megaplasmid, which encodes the non-ribosomal peptide synthetase for the production of cereulide, the emetic toxin.

Plasmid - Chromosome interplay in natural and non-natural hosts: global transcription study of three Bacillus cereus group strains carrying pCER270 plasmid.

The Bacillus cereus group comprises genetically related Gram-positive spore-forming bacteria that colonize a wide range of ecological niches and hosts. Despite their high degree of genome conservation, extrachromosomal genetic material diverges between these species. The discriminating properties of the B.

Rap-Phr Systems from Plasmids pAW63 and pHT8-1 Act Together To Regulate Sporulation in the Bacillus thuringiensis Serovar kurstaki HD73 Strain.

is a Gram-positive spore-forming bacterium pathogenic to various insect species. This property is due to the Cry toxins encoded by plasmid genes and mostly produced during sporulation. contains a remarkable number of extrachromosomal DNA molecules and a great number of plasmid genes.

Diversity of the Rap-Phr quorum-sensing systems in the Bacillus cereus group.

Bacteria of the Bacillus cereus group colonize several ecological niches and infect different hosts. Bacillus cereus, a ubiquitous species causing food poisoning, Bacillus thuringiensis, an entomopathogen, and Bacillus anthracis, which is highly pathogenic to mammals, are the most important species of this group. These species are closely related genetically, and their specific toxins are encoded by plasmids.

The signaling peptide NprX controlling sporulation and necrotrophism is imported into Bacillus thuringiensis by two oligopeptide permease systems.

The infectious cycle of Bacillus thuringiensis in the insect host is regulated by quorum sensors of the RNPP family. The activity of these regulators is modulated by their cognate signaling peptides translocated into the bacterial cells by oligopeptide permeases (Opp systems). In B.

InhA1-Mediated Cleavage of the Metalloprotease NprA Allows to Escape From Macrophages.

is a Gram-positive spore-forming bacterium causing food poisoning and serious opportunistic infections. These infections are characterized by bacterial accumulation in the host despite the induction of inflammation. To circumvent inflammation, bacteria must resist the bactericidal activity of professional phagocytes, which constitute a first line of host defense against pathogens.

A plasmid-borne Rap-Phr system regulates sporulation of Bacillus thuringiensis in insect larvae.

The entomopathogen Bacillus thuringiensis species harbours numerous plasmids essentially studied for their involvement in pathogenicity, as Cry-plasmids. The life cycle of B. thuringiensis in the insect host is regulated by the sequential activation of quorum sensing systems to kill, survive and sporulate.

NprR, a moonlighting quorum sensor shifting from a phosphatase activity to a transcriptional activator.

Regulation of biological functions requires factors (proteins, peptides or chemicals) able to sense and translate environmental conditions or any circumstances in order to modulate the transcription of a gene, the stability of a transcript or the activity of a protein. Quorum sensing is a regulation mechanism connecting cell density to the physiological state of a single cell. In bacteria, quorum sensing coordinates virulence, cell fate and commitment to sporulation and other adaptation properties.

Correction: Necrotrophism Is a Quorum-Sensing-Regulated Lifestyle in Bacillus thuringiensis.

[This corrects the article DOI: 10.1371/journal.ppat.

Correction: How Quorum Sensing Connects Sporulation to Necrotrophism in Bacillus thuringiensis.

[This corrects the article DOI: 10.1371/journal.ppat.

Spatio-Temporal Evolution of Sporulation in Bacillus thuringiensis Biofilm.

Bacillus thuringiensis can produce a floating biofilm which includes two parts: a ring and a pellicle. The ring is a thick structure which sticks to the culture container, while the pellicle extends over the whole liquid surface and joins the ring. We have followed over time, from 16 to 96 h, sporulation in the two biofilm parts.

How Quorum Sensing Connects Sporulation to Necrotrophism in Bacillus thuringiensis.

Bacteria use quorum sensing to coordinate adaptation properties, cell fate or commitment to sporulation. The infectious cycle of Bacillus thuringiensis in the insect host is a powerful model to investigate the role of quorum sensing in natural conditions. It is tuned by communication systems regulators belonging to the RNPP family and directly regulated by re-internalized signaling peptides.

Quorum sensing in Bacillus thuringiensis is required for completion of a full infectious cycle in the insect.

Bacterial cell-cell communication or quorum sensing (QS) is a biological process commonly described as allowing bacteria belonging to a same pherotype to coordinate gene expression to cell density. In Gram-positive bacteria, cell-cell communication mainly relies on cytoplasmic sensors regulated by secreted and re-imported signaling peptides. The Bacillus quorum sensors Rap, NprR, and PlcR were previously identified as the first members of a new protein family called RNPP.

SinR controls enterotoxin expression in Bacillus thuringiensis biofilms.

The entomopathogen Bacillus thuringiensis produces dense biofilms under various conditions. Here, we report that the transition phase regulators Spo0A, AbrB and SinR control biofilm formation and swimming motility in B. thuringiensis, just as they control biofilm formation and swarming motility in the closely related saprophyte species B.

Peptide-binding dependent conformational changes regulate the transcriptional activity of the quorum-sensor NprR.

The transcriptional regulator NprR controls the expression of genes essential for the adaptative response of Bacillus cereus. NprR belongs to the RNPP family of directly regulated quorum sensors from Gram-positive bacteria. It is activated by the re-imported signaling peptide NprX.

Activity of the Bacillus thuringiensis NprR-NprX cell-cell communication system is co-ordinated to the physiological stage through a complex transcriptional regulation.

NprR is a quorum sensor of the RNPP family found in bacteria of the Bacillus cereus group. In association with its cognate peptide NprX, NprR controls the expression of genes essential for survival and sporulation of Bacillus thuringiensis during its necrotrophic development in insects. Here, we report that the nprR-nprX genes are not autoregulated and are co-transcribed from a σ(A) -dependent promoter (PA ) located upstream from nprR.

Necrotrophism is a quorum-sensing-regulated lifestyle in Bacillus thuringiensis.

How pathogenic bacteria infect and kill their host is currently widely investigated. In comparison, the fate of pathogens after the death of their host receives less attention. We studied Bacillus thuringiensis (Bt) infection of an insect host, and show that NprR, a quorum sensor, is active after death of the insect and allows Bt to survive in the cadavers as vegetative cells.

A cell-cell communication system regulates protease production during sporulation in bacteria of the Bacillus cereus group.

In sporulating Bacillus, major processes like virulence gene expression and sporulation are regulated by communication systems involving signalling peptides and regulators of the RNPP family. We investigated the role of one such regulator, NprR, in bacteria of the Bacillus cereus group. We show that NprR is a transcriptional regulator whose activity depends on the NprX signalling peptide.

Role played by exosporium glycoproteins in the surface properties of Bacillus cereus spores and in their adhesion to stainless steel.

Bacillus cereus spores are surrounded by a loose-fitting layer called the exosporium, whose distal part is mainly formed from glycoproteins. The role played by the exosporium glycoproteins of B. cereus ATCC 14579 (BclA and ExsH) was investigated by considering hydrophobicity and charge, as well as the properties of spore adhesion to stainless steel.

The PlcR virulence regulon of Bacillus cereus.

PlcR is a Bacillus cereus transcriptional regulator, which activates gene expression by binding to a nucleotidic sequence called the 'PlcR box'. To build a list of all genes included in the PlcR regulon, a consensus sequence was identified by directed mutagenesis. The reference strain ATCC14579 sequenced genome was searched for occurrences of this consensus sequence to produce a virtual regulon.

Growth-related variations in the Bacillus cereus secretome.

Using 2-DE, transcriptional gene fusions and cell cytotoxicity assays, we followed changes in the Bacillus cereus strain ATCC14579 secretome, gene expression and culture supernatant cytotoxicity from the end of the vegetative phase up to 5 h after entry into the stationary phase. The concentration of each of the 22 proteins in the culture supernatant was determined at various times. In addition, the stability of the proteins was studied.

Bacillus cereus produces several nonproteinaceous insecticidal exotoxins.

Bacillus cereus is mainly known as a human food-borne opportunistic pathogen. Here, we used biological assays and HPLC to investigate the ability of B. cereus to produce insecticidal exotoxins during the stationary growth phase.

Distinct mutations in PlcR explain why some strains of the Bacillus cereus group are nonhemolytic.

Bacillus thuringiensis, Bacillus cereus, and Bacillus anthracis are closely related species belonging to the Bacillus cereus group. B. thuringiensis and B.

Occurrence and linkage between secreted insecticidal toxins in natural isolates of Bacillus thuringiensis.

Little is known about the occurrence and linkage between secreted insecticidal virulence factors in natural populations of Bacillus thuringiensis (Bt). We carried out a survey of 392 Bt strains isolated from various samples originating from 31 countries. The toxicity profile of the culture supernatants of these strains was determined individually against Anthonomus grandis (Coleoptera) and Spodoptera littoralis (Lepidoptera).