Laniergreene3159

veals the large repertoire and wide distribution of metallo, serine, and cysteine peptidases, especially secretory peptidases, among the Prevotella species. The information presented here could aid in the identification of the Prevotella species and the peptidases to target to decrease the excessive protein degradation in the rumen and improve dietary nitrogen utilization by ruminant animals.Polymyxin B is a last-line antibiotic for extensively resistant Gram-negative bacterial infection. Skin hyperpigmentation is a serious side effect induced by polymyxin B that severely compromises the psychological health and compliance of patients. The literature lacks mechanistic studies that explain how hyperpigmentation occurs, and this substantially hinders the development of intervention strategies and improved compliance. SK-MEL-2 cells were used for the polymyxin B-induced hyperpigmentation mechanism study. Melanin content and tyrosinase activity were measured after polymyxin B treatment. Tandem mass tag (TMT)-labeling quantitative proteomics was employed to investigate the response of SK-MEL-2 cells to polymyxin B treatment. Real-time quantitative PCR and Western blot were applied to validate the mRNA and protein levels of related genes and proteins. The melanin content and tyrosinase activity were significantly upregulated after polymyxin B treatment in SK-MEL-2 cells at 48 h and 72 h. Quantitative povides a proteomic clue to the mechanism at the cellular level for understanding polymyxin B-induced hyperpigmentation, contributing to a follow-up investigation of the corresponding PI3K/Akt signaling transduction pathway and calcium signaling pathway. The elucidation of its underlying mechanism is of great significance for patients' compliance improvement, intervention strategy, and new drug development.Due to the emergence of multidrug-resistant strains of yeasts belonging to the Candida genus, there is an urgent need to discover antifungal agents directed at alternative molecular targets. The aim of the current study was to evaluate the capacity of three different series of synthetic compounds to inhibit the Candida glabrata enzyme denominated 3-hydroxy-methyl-glutaryl-CoA reductase and thus affect ergosterol synthesis and yeast viability. Compounds 1c (α-asarone-related) and 5b (with a pyrrolic core) were selected as the best antifungal candidates among over 20 synthetic compounds studied. Both inhibited the growth of fluconazole-resistant and fluconazole-susceptible C. glabrata strains. A yeast growth rescue experiment based on the addition of exogenous ergosterol showed that the compounds act by inhibiting the mevalonate synthesis pathway. A greater recovery of yeast growth occurred for the C. glabrata 43 fluconazole-resistant (versus fluconazole-susceptible) strain and after treatment with 1c (versus 5 are inhibitors of ergosterol synthesis in yeasts. Of the more than 20 compounds studied, two were selected as the best antifungal candidates. These compounds were able to inhibit the growth and synthesis of ergosterol in C. glabrata strains, whether susceptible or resistant to fluconazole. The rational design of antifungal compounds derived from clinical drugs (statins, fibrates, etc.) has many advantages. Future studies are needed to modify the structure of the two present test compounds to obtain safer and less toxic antifungals. Moreover, it is important to carry out a more in-depth mechanistic approach.E-cigarettes (e-cigs) have drastically increased in popularity during the last decade, especially among teenagers. While recent studies have started to explore the effect of e-cigs in the oral cavity, little is known about their effects on the oral microbiota and how they could affect oral health and potentially lead to disease, including periodontitis and head and neck cancers. To explore the impact of e-cigs on oral bacteria, we selected members of the genus Streptococcus, which are abundant in the oral cavity. We exposed the commensals Streptococcus sanguinis and Streptococcus gordonii and the opportunistic pathogen Streptococcus mutans, best known for causing dental caries, to e-liquids and e-cig aerosols with and without nicotine and with and without menthol flavoring and measured changes in growth patterns and biofilm formation. Our results demonstrate that e-cig aerosols hindered the growth of S. sanguinis and S. gordonii, while they did not affect the growth of S. mutans. We also show that e-cig aerosttachment for the pathogen S. mutans. These results indicate that e-cigarette vaping could open a niche for opportunistic bacteria such as S. mutans to colonize the oral cavity and affect oral health.Phenylpyruvate decarboxylase (PPDC) is a crucial enzyme that plays important roles in 2-phenylethanol (2-PE) biosynthesis. In our previous study, we screened a highly efficient PPDC KDC4427 from the novel 2-PE-producing strain Enterobacter sp. CGMCC 5087. Meanwhile, its decarboxylation activity of indolylpyruvate (IPyA) was also higher than other indolylpyruvate decarboxylases (IPDCs) reported so far. In this study, KDC4427 protein was purified and characterized, and its catalytic mechanisms were analyzed by biological methods. The optimum pH and temperature of KDC4427 was pH 6.5 and 35°C, respectively. The enzyme activity was relatively stable between pH 6 and 8 and over the range of temperatures from 25°C to 45°C. KDC4427 showed the highest catalytic efficiency on phenylpyruvic acid (PPA); meanwhile, it also showed high activity for IPyA and 2-ketobutanoic acid, and it was found that KDC4427 belongs to IPDCs by phylogenetic tree analysis. The coverage of the three-dimensional structure of KDC4427 and EcIPDCtion of 2-PE. In this regard, KDC4427 can catalyze phenylpyruvic acid (PPA) to phenylacetaldehyde more efficiently than any other PPDC previously reported. Moreover, it has high activity of indolepyruvate decarboxylases (IPDCs), which will be a great breakthrough in the synthesis of indole-3-acetic acid (IAA). With this study, we offer insights into the KDC4427 catalytic mechanism and significantly expand the toolbox of available α-ketoacid decarboxylases for application in biosynthesis.Endolysin is a phage-encoded cell-wall hydrolase which degrades the peptidoglycan layer of the bacterial cell wall. The enzyme is often expressed at the late stage of the phage lytic cycle and is required for progeny escape. Endolysins of bacteriophage that infect Gram-positive bacteria often comprises two domains a peptidoglycan hydrolase and a cell-wall binding domain (CBD). Although the catalytic domain of endolysin is relatively well-studied, the precise role of CBD is ambiguous and remains controversial. Here, we focus on the function of endolysin CBD from a recently isolated Clostridioides difficile phage. We found that the CBD is not required for lytic activity, which is strongly prevented by the surface layer of C. difficile. Intriguingly, hidden Markov model analysis suggested that the endolysin CBD is likely derived from the CWB2 motif of C. difficile cell-wall proteins but possesses a higher binding affinity to bacterial cell-wall polysaccharides. Moreover, the CBD forms a homodimer, formation of wating module of bacterial cell-wall proteins, likely acquired during phage-host coevolution. The interaction of CBD to bacterial cell walls reduces enzyme diffusion and thereby limits cell lysis of the neighboring bacteria. Our findings indicate that the endolysin is trapped to the cell-wall residuals through CBD and might serve as an advantage for phage replication. Thus, employing a CBD-less endolysin might be a feasible strategy for using endolysin for the treatment of C. difficile infection.Emerging evidence has shown an association between the composition of intestinal microbial communities and host physical activity, suggesting that modifications of the gut microbiota composition may support training, performance, and post-exercise recovery of the host. Nevertheless, investigation of differences in the gut microbiota between athletes and individuals with reduced physical activity is still lacking. In this study, we performed a meta-analysis of 207 publicly available shotgun metagenomics sequencing data of fecal samples from athletes and healthy non-athletes. Accordingly, analysis of species-level fecal microbial profiles revealed three recurring compositional patterns, named HPC1 to 3, that characterize the host based on their commitment to physical activity. Interestingly, the gut microbiome of athletes showed a higher abundance of anti-inflammatory, health-promoting bacteria than that of non-athletic individuals. Moreover, the bacterial species profiled in the gut of professional athletes are short-fatty acid producers, which potentially improve energy production, and therefore sports performances. NS105 Intriguingly, microbial interaction network analyses suggested that exercise-induced microbiota adaptation involves the whole microbial community structure, resulting in a complex microbe-microbe interplay driven by positive relationships among the predicted butyrate-producing community members. IMPORTANCE Through metagenomic analyses, this work revealed that athletes have a gut-associated microbial community enriched in butyrate-producing species compared with non-athletes. This evidence can support the existence of a two-way association between the host's lifestyle and the gut microbiota composition, with potential intriguing athletic performance outcomes.Up to 4-fold differences in zinc concentrations have been observed in commercial broth routinely utilized for susceptibility testing via manual broth microdilution. Herein, we report the concentration of zinc in the broth of common automated susceptibility testing (AST) platforms (Vitek, MicroScan, BD Phoenix, and Sensititre). For AST platforms with lyophilized broth contents (Vitek and MicroScan), wells were rehydrated with appropriate diluent, and contents were aliquoted out for zinc assay. Aliquots from the manufacturer-specific broth (premade cation-adjusted Mueller-Hinton broth [caMHB]) for BD Phoenix and Sensititre were also assayed by inductively coupled plasma mass spectrometry. Up to a 10-fold difference in zinc concentrations was observed across the 4 platforms (MicroScan 0.46 mg/L; BD Phoenix 1.16 mg/L; Vitek 1.22 mg/L; Sensititre 4.49 mg/L). Attention should be given to the supraphysiologic and variable zinc concentrations observed in broth used in automated platforms and the subsequent implications for susceptibility testing of metallo-β-lactamase (MBL)-harboring isolates. This variability also hampers efforts to develop a standardized method to uniformly reduce zinc concentrations in broth and mimic physiologic zinc conditions. IMPORTANCE Growing data on the impact of extracellular zinc concentration on metallo-β-lactamase-mediated resistance has shed light on the importance of susceptibility testing media. However, there are no studies documenting the amount of zinc in commonly utilized automated susceptibility testing (AST) platforms. This study reveals supraphysiologic zinc concentrations as well as large zinc variability among AST platforms and highlights the challenges this raises in the development of zinc-limited media.