Antimicrobial resistance (AMR) is becoming a huge problem in countries all over the world, and new approaches to identifying strains resistant or susceptible to certain antibiotics are essential in fighting against antibiotic-resistant pathogens. Genotype-based machine learning methods showed great promise as a diagnostic tool, due to the increasing availability of genomic datasets and AST phenotypes. In this article, Support Vector Machine (SVM) and Set Covering Machine (SCM) models were used to learn and predict the resistance of the five drugs (Tetracycline, Ampicillin, Sulfisoxazole, Trimethoprim, and Enrofloxacin). The SVM model used the number of co-occurring k-mers between the genome of the isolates and the reference genes to learn and predict the phenotypes of the bacteria to a specific antimicrobial, while the SCM model uses a greedy approach to construct conjunction or disjunction of Boolean functions to find the most concise set of k-mers that allows for accurate prediction of the phenotype. Five-fold cross-validation was performed on the training set of the SVM and SCM model to select the best hyperparameter values to avoid model overfitting. The training accuracy (mean cross-validation score) and the testing accuracy of SVM and SCM models of five drugs were above 90% regardless of the resistant mechanism of which were acquired resistant or point mutation in the chromosome. The results of correlation between the phenotype and the model predictions of the five drugs indicated that both SVM and SCM models could significantly classify the resistant isolates from the sensitive isolates of the bacteria (p < 0.01), and would be used as potential tools in antimicrobial resistance surveillance and clinical diagnosis in veterinary medicine.

Inhibitors and Activators of SOD, GSH‐Px, and CAT | InTechOpen, Published on: 2017-03-29. Authors: Xianyong Ma, Dun Deng and Weidong Chen

The accumulation of reactive oxygen species (ROS) triggers oxidative stress in cells by oxidizing and modifying various cellular components, preventing them from performing their inherent functions, ultimately leading to apoptosis and autophagy. Glutathione (GSH) is a ubiquitous intracellular peptide with multiple functions. In this study, a hydrogen peroxide (H${}_2$O${}_2$)-induced oxidative damage model in IPEC-J2 cells was used to investigate the cellular protection mechanism of exogenous GSH against oxidative stress. The results showed that GSH supplement improved the cell viability reduced by H${}_2$O${}_2$-induced oxidative damage model in IPEC-J2 cells in a dose-dependent manner. Moreover, supplement with GSH also attenuated the H${}_2$O${}_2$-induced MMP loss, and effectively decreased the H${}_2$O${}_2$-induced mitochondrial dysfunction by increasing the content of mtDNA and upregulating the expression TFAM. Exogenous GSH treatment significantly decreased the ROS and MDA levels, improved SOD activity in H${}_2$O${}_2$-treated cells and reduced H${}_2$O${}_2$-induced early apoptosis in IPEC-J2 cells. This study showed that exogenous GSH can protect IPEC-J2 cells against apoptosis induced by oxidative stress through mitochondrial mechanisms.

Scope: Probiotics are a potential preventive strategy for obesity. However, with discrete efficacy and limited species of probiotics, there is a demand for novel strains with excellent anti-obesity properties. This study aimed to investigate the effects of Brevibacillus laterosporus BL1 on preventing obesity in high-fat diet (HFD)-fed mice.Methods and results: C57BL/6 male mice were randomly assigned to four groups (n = 10) and fed a control diet, HFD, HFD plus B. laterosporus BL1, and HFD plus supernatant of B. laterosporus BL1, respectively for 8 weeks. The results showed that prophylactic B. laterosporus BL1 treatment reduced body weight gain by 41.26% in comparison to the HFD group, and this difference was accompanied by a reduction in body fat mass and the weight of inguinal white adipose tissues and epididymal white adipose tissue (−33.39%, −39.07%, and −43.75%, respectively). Moreover, the B. laterosporus BL1-mediated improvements in lipid profile, insulin resistance, and chronic inflammation were associated with the regulation of gene expression related to lipid metabolism and enhancement of brown adipose tissue thermogenesis. Particularly, B. laterosporus BL1 intervention significantly improved HFD-induced gut flora dysbiosis, as evidenced by a reverse in the relative abundance of Bacillota and Bacteroidota, as well as an increase in the relative abundance of bacteria that produce short-chain fatty acids (SCFAs), which in turn increased SCFAs levels.Conclusion: Our findings found for the first time that B. laterosporus BL1 may be a promising probiotic for prevention of obesity associated with the regulation of gut microbiota.

Brevibacillus laterosporus (B. laterosporus) is widely distributed in nature and demonstrates significant potential for applications in biological control, environmental protection, agricultural production, and clinical medicine. This review provides a comprehensive overview of the applications of B. laterosporus in crop cultivation and animal feeding, as well as an examination of the antimicrobial peptides produced by B. laterosporus and their antibacterial mechanisms. B. laterosporus enhances crop cultivation by secreting hydrolases to improve nutrient absorption capabilities, synthesizing hormones to promote crop growth, and producing proteins to inhibit the reproduction of harmful organisms. B. laterosporus has been used to improve animal production by regulating the structure of the intestinal microbiota and inhibiting the growth of pathogenic bacteria through the secretion of various antimicrobial peptides. The bactericidal activity of Brevilaterins secreted by B. laterosporus is attributed to their ability to bind to lipopolysaccharide/lipid II molecules on the cell membrane, thereby altering permeability. Brevilaterins also inhibit bacterial reproduction by affecting relevant gene pathways in the cell membranes of pathogenic bacteria. These pathways include ATP synthesis, peptidoglycan biosynthesis, membrane transport, and cellular metabolism. In conclusion, B. laterosporus exhibits substantial potential as a probiotic activity in crop and animal production. However, applications of B. laterosporus in animal production could be improved, necessitating further research to elucidate the underlying probiotic mechanisms.