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Frontiers in Microbiology 2023High hydrostatic pressure (HHP) regulated gene expression is one of the most commonly adopted strategies for microbial adaptation to the deep-sea environments....
High hydrostatic pressure (HHP) regulated gene expression is one of the most commonly adopted strategies for microbial adaptation to the deep-sea environments. Previously we showed that the HHP-inducible trimethylamine N-oxide (TMAO) reductase improves the pressure tolerance of deep-sea strain QY27. Here, we investigated the molecular mechanism of HHP-responsive regulation of TMAO reductase TorA. By constructing and deletion mutants, we demonstrated that the two-component regulator TorR and sensor TorS are responsible for the HHP-responsive regulation of . Unlike known HHP-responsive regulatory system, the abundance of and was not affected by HHP. Complementation of the Δ mutant with TorS altered at conserved phosphorylation sites revealed that the three sites were indispensable for substrate-induced regulation, but only the histidine located in the alternative transmitter domain was involved in pressure-responsive regulation. Taken together, we demonstrated that the induction of TMAO reductase by HHP is mediated through the TorRS system and proposed a bifurcation of signal transduction in pressure-responsive regulation from the substrate-induction. This work provides novel knowledge of the pressure regulated gene expression and will promote the understanding of the microbial adaptation to the deep-sea HHP environment.
PubMed: 38029070
DOI: 10.3389/fmicb.2023.1291578 -
Complete genomic sequence of strain IDH5335 isolated from a patient with diarrhea in Kolkata, India.Microbiology Resource Announcements Dec 2023We isolated a strain (IDH5335) from a stool sample collected from a patient with diarrhea. In this announcement, we report the complete genomic sequence of this...
We isolated a strain (IDH5335) from a stool sample collected from a patient with diarrhea. In this announcement, we report the complete genomic sequence of this organism, which was obtained by combining Illumina and Oxford Nanopore sequencing data.
PubMed: 37943041
DOI: 10.1128/MRA.00707-23 -
Journal of Global Antimicrobial... Dec 2023
Topics: Genomic Islands; Salmonella; beta-Lactamases
PubMed: 37748579
DOI: 10.1016/j.jgar.2023.09.014 -
Chembiochem : a European Journal of... Dec 2023Furan-based amines are highly valuable compounds which can be directly obtained via reductive amination from easily accessible furfural, 5-(hydroxymethyl)furfural (HMF)...
Furan-based amines are highly valuable compounds which can be directly obtained via reductive amination from easily accessible furfural, 5-(hydroxymethyl)furfural (HMF) and 2,5-diformylfuran (DFF). Herein the biocatalytic amination of these carbonyl derivatives is disclosed using amine transaminases (ATAs) and isopropylamine (IPA) as amine donors. Among the different biocatalysts tested, the ones from Chromobacterium violaceum (Cv-TA), Arthrobacter citreus (ArS-TA), and variants from Arthrobacter sp. (ArRmut11-TA) and Vibrio fluvialis (Vf-mut-TA), afforded high levels of product formation (>80 %) at 100-200 mM aldehyde concentration. The transformations were studied in terms of enzyme and IPA loading. The pH influence was found as a key factor and attributed to the imine/aldehyde equilibrium that can arise from the high reactivity of the carbonyl substrates with a nucleophilic amine such as IPA.
Topics: Aldehydes; Amines; Furans; Hydrogen-Ion Concentration
PubMed: 37737725
DOI: 10.1002/cbic.202300514 -
Cureus Jul 2023is a pathogenic Gram-negative bacillus typically resulting in gastroenteritis in humans. It has recently been identified as a growing concern for public health. The...
is a pathogenic Gram-negative bacillus typically resulting in gastroenteritis in humans. It has recently been identified as a growing concern for public health. The case presented is an uncommon case of causing bacteremia, as well as hemorrhagic skin lesions. Other reported cases have also highlighted unexpected manifestations, such as cerebritis, bacterial peritonitis, and otitis externa. These atypical presentations can happen in immunocompromised individuals. There are no established guidelines currently for the treatment of bacteremia. This case presents bacteremia that improved with doxycycline without the need for incision and drainage of the patient's lower extremity lesions.
PubMed: 37521591
DOI: 10.7759/cureus.42612 -
Chembiochem : a European Journal of... Oct 2023An enzyme cascade was established previously consisting of a recycling system with an l-amino acid oxidase (hcLAAO4) and a catalase (hCAT) for different α-keto acid...
An enzyme cascade was established previously consisting of a recycling system with an l-amino acid oxidase (hcLAAO4) and a catalase (hCAT) for different α-keto acid co-substrates of (S)-selective amine transaminases (ATAs) in kinetic resolutions of racemic amines. Only 1 mol % of the co-substrate was required and l-amino acids instead of α-keto acids could be applied. However, soluble enzymes cannot be reused easily. Immobilization of hcLAAO4, hCAT and the (S)-selective ATA from Vibrio fluvialis (ATA-Vfl) was addressed here. Immobilization of the enzymes together rather than on separate beads showed higher reaction rates most likely due to fast co-substrate channeling between ATA-Vfl and hcLAAO4 due to their close proximity. Co-immobilization allowed further reduction of the co-substrate amount to 0.1 mol % most likely due to a more efficient H O -removal caused by the stabilized hCAT and its proximity to hcLAAO4. Finally, the co-immobilized enzyme cascade was reused in 3 cycles of preparative kinetic resolutions to produce (R)-1-PEA with high enantiomeric purity (97.3 %ee). Further recycling was inefficient due to the instability of ATA-Vfl, while hcLAAO4 and hCAT revealed high stability. An engineered ATA-Vfl-8M was used in the co-immobilized enzyme cascade to produce (R)-1-(3-ethoxy-4-methoxyphenyl)-2-(methylsulfonyl)ethanamine, an apremilast-intermediate, with a 1,000 fold lower input of the co-substrate.
Topics: Amines; Transaminases; L-Amino Acid Oxidase; Enzymes, Immobilized; Catalase; Keto Acids
PubMed: 37368451
DOI: 10.1002/cbic.202300425