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Bacteria - OSTI GOV

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Last Updated: 27 August 2022

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Microbial Tracking-2, a metagenomics analysis of bacteria and fungi onboard the International Space Station

The International Space Station is a unique and complex built environment with the ISS surface microbiome originating from crew and cargo or life support recirculation in a virtually closed system. The Microbial Tracking 1 project was the first ISS environmental surface research to report on the metagenome profiles without using whole-genome amplification. The Microbial Tracking 2 project was designed to extend the MT-1's research by obtaining four flights from the same locations over the course of 14 months. DNA extracted from the processed samples was treated with propidium monoazide to identify intact/liveable cells or left untreated, as well as the total DNA population. Using shotgun metagenomics, DNA extracted from PMA-treated and untreated samples was analyzed using shotgun metagenomics. Overall, the ISS surface microbiome was dominated by organisms associated with human skin. The ISS antimicrobial resistance gene profiles remained relatively stable over time, with no change between the MT-1 and MT-2 studies' 5-year intervals. Antimicrobial resistance genes were present in all samples, with macrolide/lincosamide/streptogramin resistance being the most common. A comprehensive review of the ISS surface microbiome, including microbial burden, bacterial and fungal species prevalence, changes in the microbiome, and resistanceome with time and space, as well as the functional properties and microbial interactions of this unique built microbiome, using various metagenomics and culture techniques. The results from this research can help to develop policies for future space missions in order to ensure that an ISS surface microbiome that promotes astronaut health and spacecraft integrity is maintained.

Source link: https://www.osti.gov/biblio/1881622


A Defined Medium for Cultivation and Exometabolite Profiling of Soil Bacteria

Exometabolomics is a way to determine how microorganisms influence, or react to their environments by depletion and production of metabolites. It allows the investigation of how soil microbes alter the tiny molecule metabolites in their environment, which can be used to determine resource competition and cross-feeding. However, microbial growth media have traditionally been used for the isolation and growth of microorganisms, but not metabolite utilization profiling by Liquid Chromatography Tandem Mass Spectrometry. Different bacteria, including Metabolites in NLDM, were chosen based on their availability in R2A medium and soil, elemental stoichiometry, and knowledge of metabolite use by various bacteria. NLDM supported the growth of 108 of the 110 phylogenetically diverse soil bacterial isolates tested, as well as all of its metabolites, according to LC/MS results.

Source link: https://www.osti.gov/biblio/1878499


CRAGE-CRISPR facilitates rapid activation of secondary metabolite biosynthetic gene clusters in bacteria

Secondary metabolite biosynthetic gene clusters within bacterial genomes are becoming more popular with the introduction of genome sequencing and mining technologies. Here we outline a scheme that incorporates CRISPR with chassis-independent recombinase-assisted genome engineering, which allows CRISPR systems to exist in a variety of bacteria. We choose ten polyketide/non-ribosomal peptide BGCs in Photorhabdus luminescens as models and produce their deletion and activation mutants to demonstrate CRAGE-CRISPR.

Source link: https://www.osti.gov/biblio/1881880


How to Evaluate Non-Growing Cells—Current Strategies for Determining Antimicrobial Resistance of VBNC Bacteria

Bacteria that enter the VBNC state, whether due to poor environmental conditions or perhaps lethal stress, lose their ability to grow on standard enrichment media, but antibiotic-resistant bacteria have a drastic tolerance. VBNCs can be detected and quantified by experimental methods, but only a few have been used for antimicrobial resistance screening, and this article seeks to give an overview of current methodology.

Source link: https://www.osti.gov/biblio/1815956


Emission lineshapes of the B850 band of light-harvesting 2 (LH2) complex in purple bacteria: A second order time-nonlocal quantum master equation approach

By extending the approach of the 2nd order time-nonlocal quantum master equation, J. Jang and R. J. Silbey, J. Chem, calculate the emission lineshape of the B850 band in the light harvesting complex 2 of purple bacteria is estimated. The initial condition for the emission process corresponds to the stable excited state density, where exciton states are tightly linked to the bath modes in equilibrium. Both full 2nd order lineshape expression and one based on secular approximation neglecting off-diagonal components in the exciton framework are derived, with careful treatment of all the 2nd order terms being initiated, and specific expressions are developed for both full and partial 2nd order lineshape expression and one based on secular approximation neglecting off-diagonal components in the exciton framework. A comparison of emission line shape to the absorption line shape is also made. The comparison of emission and absorption lineshapes at various temperatures reveals the importance of thermal population of various exciton states and exciton couplings.

Source link: https://www.osti.gov/biblio/1751947

* Please keep in mind that all text is summarized by machine, we do not bear any responsibility, and you should always check original source before taking any actions

* Please keep in mind that all text is summarized by machine, we do not bear any responsibility, and you should always check original source before taking any actions