Characterization of toxigenic genes of Bacillus cereus strains isolated from different spices sold in Algeria.

Many cooked foods are prepared with spices and dried herbs; these can be contaminated by several types of microorganisms, including aerobic spore-forming bacteria. The Bacillus cereus group is very widespread in nature and is known among the common food contaminants. They are involved in food poisoning, causing two types of syndromes, diarrheal and emetic. The aims of the present work were to determine the prevalence of toxigenic Bacillus cereus spores in spices and herbs marketed in the Laghouat area and to identify their toxigenic genes via PCR. Among the 191 samples, 14.13% were determined to be B. cereus, with concentrations ranging from 2.52 to 5.82 log cfu/g, where the highest level of contamination was observed in allspice and ginger. Moreover, entFM (100%), nhe (88.23%) and cytK (70.58%) were the most frequently identified toxin genes, whereas hbl (23.52%) was less common, and no emetic toxin-encoding gene (cesB) was found in any of the samples. Considering the results of the present study, the B. cereus microbial load and toxin gene profiles of spices show that spices have potential for public health in Algeria. In this context, it is crucial to guarantee the microbiological safety of spices by respecting good hygiene practices, eliminating bacterial spores and toxin production via sterilization and using appropriate packaging for these products.

In silico and in vitro studies: investigating the chemical composition, DFT, molecular docking, and dynamic simulation of Satureja candidissima (Munby) Briq essential oil as a potential antibacterial agent.

This study aimed to investigate the chemical composition and antibacterial properties of the essential oil (EO) derived from the aerial parts of Satureja candidissima (Munby) Briq (SC), as well as the mechanisms of interaction between SCEO chemical components and target proteins related to antibacterial activity mechanisms using a molecular docking approach, and for more accuracy molecular dynamic simulation and DFT calculations were carried out. The GC-MS technique was used to analyze the chemical composition of SCEO. The results showed that SCEO contained various chemical compounds, with pulegone being identified as the major component (53.26%). The results also indicated the presence of (+)-menthone (11.02%), borneol (4.43%), 2-cyclohexen-1-one, 3-methyl-6-(1-methylethylidene) (2.50%), and 3-octanol (2.09%). The study revealed that the SCEO displayed antibacterial activity against all tested gram-positive bacteria. To further understand the mechanism behind its antibacterial activity, in silico molecular docking studies were performed. The results indicated that the antibacterial effect of SCEO compounds could be due to the combination with enoyl-[acyl-carrier-protein] reductase [NADPH] FabI (PDB ID: 4ALL) in a variety of ways. The molecular dynamics simulation analysis yielded favorable outcomes for the docked complex involving 1H-cycloprop[e]azulen-7-ol, decahydro-1,1,7-trimethyl-4-methylene, and 1,4,7-tetramethyldecahydro-1H-cyclopropa[e]azulen-4-ol with enoyl-[acyl-carrier-protein] reductase [NADPH]. Geometry optimization, coupled with Density Functional Theory (DFT), can be employed to assess the importance of quantum chemical descriptors in elucidating potential antibacterial activity. Quantum descriptors were computed based on EHOMO and ELUMO. The results of this study provide important insights into the potential use of Satureja candidissima (Munby) Briq EO as antibacterial agent.Communicated by Ramaswamy H. Sarma.

EONS: an online synaptic modeling platform.

Chemical synapses, although representing the smallest unit of communication between two neurons in the nervous system constitute a complex ensemble of mechanisms. Understanding these mechanisms and the way synaptic transmission occurs is critical for our comprehension of CNS functions in general and learning and memory in particular. Here we describe a modeling platform called EONS (Elementary Object of Neural System) accessible online, which allows neuroscientists throughout the world to study qualitatively, but also quantitatively the relative contributions of diverse mechanisms underlying synaptic efficacy: the relevance of each and every elements that comprise a synapse, the interactions between these components and their subcellular distribution, as well as the influence of synaptic geometry (presynaptic terminal, cleft and postsynaptic density).