New pieces to the carbon metabolism puzzle of Nitrosomonas europaea: Kinetic characterization of glyceraldehyde-3 phosphate and succinate semialdehyde dehydrogenases

First Report on the Versatile Secretome of an Environmental Isolate Acinetobacter pittii S-30

Acinetobacter species is currently ranked as high-priority pathogen for their extraordinary ability to become resistant to almost all existing antibiotics. The diverse range of effectors secreted by Acinetobacter spp. constitutes a significant proportion of the virulence arsenal. Therefore, our study aims to characterize the secretome of Acinetobacter pittii S-30. Analysis of extracellular secreted proteins of A. pittii S-30 revealed the presence of transporter proteins, outer membrane proteins, molecular chaperones, porins, and several proteins of unknown function. Additionally, proteins related to metabolism, as well as those involved in gene expression and protein translation, type VI secretion system (T6SS) proteins, and stress response-related proteins were also identified in the secretome. The comprehensive analysis of secretome revealed putative protein antigens which could elicit substantial immune response. The limited availability of effective antibiotics and the worldwide growth of secretome data make this approach appealing in the development of effective vaccines against Acinetobacter and other bacterial pathogens.

Keystone taxa and functional analysis in arsenic and antimony co-contaminated rice terraces

Both arsenic (As) and antimony (Sb) are primary environmental contaminants that often co-exist at contaminated sites. Though the microbial community compositions of As- and Sb-contaminated sites have been previously described, the changes in microbial community interactions and community functions remain elusive. In the current study, several key metabolic processes, such as As/Sb detoxification and carbon fixation, were enriched under heavily contaminated conditions. Furthermore, the identified keystone taxa, which are associated with the families Nitrosomonadaceae, Pedosphaeraceae, Halieaceae, and Latescibacterota, demonstrated positive correlations with As and Sb concentrations, indicating that they may be resistant to As and Sb toxicities. Accordingly, arsenic resistance-related functions, along with several functions such as carbon fixation, were found to be enriched in heavily contaminated sites. The current study elucidated the key microbial populations in As- and Sb-contaminated rice terraces and may provide useful information for remediation purposes.

Proteomic Analyses of Acinetobacter baumannii Clinical Isolates to Identify Drug Resistant Mechanism

Acinetobacter baumannii is one of the main causes of nosocomial infections. Increasing numbers of multidrug-resistant Acinetobacter baumannii cases have been reported in recent years, but its antibiotic resistance mechanism remains unclear. We studied 9 multidrug-resistant (MDR) and 10 drug-susceptible Acinetobacter baumannii clinical isolates using Label free, TMT labeling approach and glycoproteomics analysis to identify proteins related to drug resistance. Our results showed that 164 proteins exhibited different expressions between MDR and drug-susceptible isolates. These differential proteins can be classified into six groups: a. proteins related to antibiotic resistance, b. membrane proteins, membrane transporters and proteins related to membrane formation, c. Stress response-related proteins, d. proteins related to gene expression and protein translation, e. metabolism-related proteins, f. proteins with unknown function or other functions containing biofilm formation and virulence. In addition, we verified seven proteins at the transcription level in eight clinical isolates by using quantitative RT-PCR. Results showed that four of the selected proteins have positive correlations with the protein level. This study provided an insight into the mechanism of antibiotic resistance of multidrug-resistant Acinetobacter baumannii.