-
AMB Express May 2022Psychrotrophic Pseudomonas is one of the significant microbes that lead to putrefaction in chilled meat. One of the biggest problems in the detection of Pseudomonas is...
Psychrotrophic Pseudomonas is one of the significant microbes that lead to putrefaction in chilled meat. One of the biggest problems in the detection of Pseudomonas is that several species are seemingly identical. Currently, antibiotic resistance is one of the most significant challenges facing the world's health and food security. Therefore, this study was designed to apply an accurate technique for eliminating the identification discrepancy of Pseudomonas species and to study their resistance against various antimicrobials. A total of 320 chicken meat specimens were cultivated, and the isolated bacteria' were phenotypically recognized. Protein analysis was carried out for cultured isolates via Microflex LT. The resistance of Pseudomonas isolates was recorded through Vitek® 2 AST-GN83 cards. Overall, 69 samples were identified as Pseudomonas spp. and included 18 Pseudomonas lundensis (P. lundensis), 16 Pseudomonas fragi (P. fragi), 13 Pseudomonas oryzihabitans (P. oryzihabitans), 10 Pseudomonas stutzeri (P. stutzeri), 5 Pseudomonas fluorescens (P. fluorescens), 4 Pseudomonas putida (P. putida), and 3 Pseudomonas aeruginosa (P. aeruginosa) isolates. Microflex LT identified all Pseudomonas isolates (100%) correctly with a score value ≥ 2.00. PCA positively discriminated the identified isolates into various groups. The antimicrobial resistance levels against Pseudomonas isolates were 81.16% for nitrofurantoin, 71% for ampicillin and ampicillin/sulbactam, 65.22% for cefuroxime and ceftriaxone, 55% for aztreonam, and 49.28% for ciprofloxacin. The susceptibilities were 100% for cefotaxime, 98.55% for ceftazidime, 94.20% for each piperacillin/tazobactam and cefepime, 91.3% for cefazolin. In conclusion, chicken meat was found to be contaminated with different Pseudomonas spp., with high incidence rates of P. lundensis. Microflex LT is a potent tool for distinguishing Pseudomonads at the species level.
PubMed: 35532863
DOI: 10.1186/s13568-022-01390-1 -
International Journal of Molecular... Feb 2022Rhamnolipids are becoming an important class of glycolipid biosurfactants. Herein, we describe for the first time the enzymatic synthesis of rhamnose fatty acid esters...
Rhamnolipids are becoming an important class of glycolipid biosurfactants. Herein, we describe for the first time the enzymatic synthesis of rhamnose fatty acid esters by the transesterification of rhamnose with fatty acid vinyl esters, using lipase from as a biocatalyst. The use of this lipase allows excellent catalytic activity in the synthesis of 4--acylrhamnose (99% conversion and full regioselectivity) after 3 h of reaction using tetrahydrofuran (THF) as the reaction media and an excess of vinyl laurate as the acyl donor. The role of reaction conditions, such as temperature, the substrates molar ratio, organic reaction medium and acyl donor chain-length, was studied. Optimum conditions were found using 35 °C, a molar ratio of 1:3 (rhamnose:acyldonor), solvents with a low logP value, and fatty acids with chain lengths from C4 to C18 as acyl donors. In hydrophilic solvents such as THF and acetone, conversions of up to 99-92% were achieved after 3 h of reaction. In a more sustainable solvent such as 2-methyl-THF (2-MeTHF), high conversions were also obtained (86%). Short and medium chain acyl donors (C4-C10) allowed maximum conversions after 3 h, and long chain acyl donors (C12-C18) required longer reactions (5 h) to get 99% conversions. Furthermore, scaled up reactions are feasible without losing catalytic action and regioselectivity. In order to explain enzyme regioselectivity and its ability to accommodate ester chains of different lengths, homology modelling, docking studies and molecular dynamic simulations were performed to explain the behaviour observed.
Topics: Biocatalysis; Enzymes, Immobilized; Esterification; Esters; Fatty Acids; Hydrophobic and Hydrophilic Interactions; Laurates; Lipase; Pseudomonas stutzeri; Rhamnose; Solvents; Vinyl Compounds
PubMed: 35216354
DOI: 10.3390/ijms23042239 -
Synthetic and Systems Biotechnology Dec 2023A1501 is a non-fluorescent denitrifying bacteria that belongs to the gram-negative bacterial group. As a prominent strain in the fields of agriculture and...
A1501 is a non-fluorescent denitrifying bacteria that belongs to the gram-negative bacterial group. As a prominent strain in the fields of agriculture and bioengineering, there is still a lack of comprehensive understanding regarding its metabolic capabilities, specifically in terms of central metabolism and substrate utilization. Therefore, further exploration and extensive studies are required to gain a detailed insight into these aspects. This study reconstructed a genome-scale metabolic network model for A1501 and conducted extensive curations, including correcting energy generation cycles, respiratory chains, and biomass composition. The final model, iQY1018, was successfully developed, covering more genes and reactions and having higher prediction accuracy compared with the previously published model iPB890. The substrate utilization ability of 71 carbon sources was investigated by BIOLOG experiment and was utilized to validate the model quality. The model prediction accuracy of substrate utilization for A1501 reached 90 %. The model analysis revealed its new ability in central metabolism and predicted that the strain is a suitable chassis for the production of Acetyl CoA-derived products. This work provides an updated, high-quality model of A1501for further research and will further enhance our understanding of the metabolic capabilities.
PubMed: 37927897
DOI: 10.1016/j.synbio.2023.10.001 -
Turkish Journal of Pharmaceutical... Feb 2021Tamoxifen (TAM), which is used for treating breast cancer, has exhibited another important function as an antimicrobial agent. The objective of this study is to...
OBJECTIVES
Tamoxifen (TAM), which is used for treating breast cancer, has exhibited another important function as an antimicrobial agent. The objective of this study is to investigate the antibacterial action of TAM against the bacteria present in the human oral cavity.
MATERIALS AND METHODS
The bacteria present in the human oral cavity were isolated from healthy individuals. Different concentrations of TAM were tested against the isolated bacteria. Additionally, bactericidal and bacteriostatic effects of TAM were also determined.
RESULTS
Out of 23 isolated bacteria, a greater number of Gram-positive bacteria were highly susceptible to the low concentrations of TAM than Gram-negative bacteria. , which is Gram-positive bacterium, and , which is Gram-negative bacterium, needed a high minimum inhibitory concentration value of TAM (2.5 mg/mL) to be inhibited by TAM's bacteriostatic action. Resistance to TAM was also observed in three strains of Gram-positive and four strains of Gram-negative bacteria.
CONCLUSION
TAM has shown a potential antibacterial effect against the bacteria present in the oral cavity, especially against Gram-positive bacteria. This effect is mostly bacteriostatic. This study also found bacterial resistance toward TAM.
PubMed: 33634670
DOI: 10.4274/tjps.galenos.2019.23500 -
Molecular Plant-microbe Interactions :... Sep 2023spp. make up 1.6% of the bacteria in the soil and are found throughout the world. More than 140 species of this genus have been identified, some beneficial to the...
spp. make up 1.6% of the bacteria in the soil and are found throughout the world. More than 140 species of this genus have been identified, some beneficial to the plant. Several species in the family Pseudomonadaceae, including AvOP, A1501, DSM4166, 6HT33bT, and sp. strain K1 can fix nitrogen from the air. The genes required for these reactions are organized in a nitrogen fixation island, obtained via horizontal gene transfer from , , and . Today, this island is conserved in spp. from different geographical locations, which, in turn, have evolved to deal with different geo-climatic conditions. Here, we summarize the molecular mechanisms behind -driven plant growth promotion, with particular focus on improving plant performance at limiting nitrogen (N) and improving plant N content. We describe -plant interaction strategies in the soil, noting that the mechanisms of denitrification, ammonification, and secondary metabolite signaling are only marginally explored. Plant growth promotion is dependent on the abiotic conditions and differs at sufficient and deficient N. The molecular controls behind different plant responses are not fully elucidated. We suggest that superposition of transcriptome, proteome, and metabolome data and their integration with plant phenotype development through time will help fill these gaps. The aim of this review is to summarize the knowledge behind -driven nitrogen fixation and to point to possible agricultural solutions. [Formula: see text] Copyright © 2023 The Author(s). This is an open access article distributed under the CC BY 4.0 International license.
PubMed: 36989040
DOI: 10.1094/MPMI-10-22-0223-CR -
MSphere Jun 2024The RNA chaperone Hfq acts as a global regulator of numerous biological processes, such as carbon/nitrogen metabolism and environmental adaptation in plant-associated...
UNLABELLED
The RNA chaperone Hfq acts as a global regulator of numerous biological processes, such as carbon/nitrogen metabolism and environmental adaptation in plant-associated diazotrophs; however, its target RNAs and the mechanisms underlying nitrogen fixation remain largely unknown. Here, we used enhanced UV cross-linking immunoprecipitation coupled with high-throughput sequencing to identify hundreds of Hfq-binding RNAs probably involved in nitrogen fixation, carbon substrate utilization, biofilm formation, and other functions. Collectively, these processes endow strain A1501 with the requisite capabilities to thrive in the highly competitive rhizosphere. Our findings revealed a previously uncharted landscape of Hfq target genes. Notable among these is , encoding an isomerase necessary for nitrogenase reductase solubility; , encoding an ammonium transporter; , encoding a carbohydrate porin; and , encoding a chemotaxis protein. Furthermore, we identified more than 100 genes of unknown function, which expands the potential direct regulatory targets of Hfq in diazotrophs. Our data showed that Hfq directly interacts with the mRNA of regulatory proteins (RsmA, AlgU, and NifA), regulatory ncRNA RsmY, and other potential targets, thus revealing the mechanistic links in nitrogen fixation and other metabolic pathways.
IMPORTANCE
Numerous experimental approaches often face challenges in distinguishing between direct and indirect effects of Hfq-mediated regulation. New technologies based on high-throughput sequencing are increasingly providing insight into the global regulation of Hfq in gene expression. Here, enhanced UV cross-linking immunoprecipitation coupled with high-throughput sequencing was employed to identify the Hfq-binding sites and potential targets in the root-associated A1501 and identify hundreds of novel Hfq-binding RNAs that are predicted to be involved in metabolism, environmental adaptation, and nitrogen fixation. In particular, we have shown Hfq interactions with various regulatory proteins' mRNA and their potential targets at the posttranscriptional level. This study not only enhances our understanding of Hfq regulation but, importantly, also provides a framework for addressing integrated regulatory network underlying root-associated nitrogen fixation.
Topics: Pseudomonas stutzeri; Host Factor 1 Protein; Nitrogen Fixation; Gene Expression Regulation, Bacterial; Plant Roots; RNA, Bacterial; Gene Expression Profiling; Gene Regulatory Networks; Bacterial Proteins; High-Throughput Nucleotide Sequencing; Transcriptome; Rhizosphere
PubMed: 38747590
DOI: 10.1128/msphere.00762-23 -
Frontiers in Microbiology 2018Mercury-mediated toxicity remains one of the greatest barriers against microbial survival, even though bacterial resistance to mercury compounds can occur. However, the...
Mercury-mediated toxicity remains one of the greatest barriers against microbial survival, even though bacterial resistance to mercury compounds can occur. However, the genetic and physiological adaptations of bacteria to mercury stress still remains unclear. Here, we show that the marine bacterium 273 is resistant to 50 μM Hg and removes up to 94% Hg from culture. Using gene homologous recombination and complementation, we show that genes encoding Hg-transport proteins MerT, MerP, the mercuric reductase MerA and the regulatory protein MerD are essential for bacterial mercuric resistance when challenged with Hg. Further, mercury stress inhibits flagellar development, motility, chemotaxis and biofilm formation of 273, which are verified by transcriptomic and physiological analyses. Surprisingly, we discover that MerF, a previously reported Hg-transporter, determines flagellar development, motility and biofilm formation in 273 by genetic and physiological analyses. Our results strongly indicate that MerF plays an integral role in 273 to develop physiological responses to mercury stress. Notably, MerF homologs are also prevalent in different human pathogens. Using this unique target may provide novel strategies to control these pathogenic bacteria, given the role of MerF in flagella and biofilm formation. In summary, our data provide an original report on MerF in bacterial physiological development and suggest that the in marine bacteria has evolved through progressive, sequential recruitment of novel functions over time.
PubMed: 29675016
DOI: 10.3389/fmicb.2018.00682 -
Toxins Nov 2022and the produced aflatoxins cause great hazards to food security and human health across all countries. The control of and aflatoxins in grains during storage is of...
and the produced aflatoxins cause great hazards to food security and human health across all countries. The control of and aflatoxins in grains during storage is of great significance to humans. In the current study, bacteria strain YM6 isolated from sea sediment was demonstrated effective in controlling by the production of anti-fungal volatiles. According to morphological characteristics and phylogenetic analysis, strain YM6 was identified as YM6 can produce abundant volatile compounds which could inhibit mycelial growth and conidial germination of . Moreover, it greatly prevented fungal infection and aflatoxin production on maize and peanuts during storage. The inhibition rate was 100%. Scanning electron microscopy further supported that the volatiles could destroy the cell structure of and prevent conidia germination on the grain surface. Gas chromatography/mass spectrometry revealed that dimethyl trisulfide (DMTS) with a relative abundance of 13% is the most abundant fraction in the volatiles from strain YM6. The minimal inhibitory concentration of DMTS to conidia is 200 µL/L (compound volume/airspace volume). Thus, we concluded that YM6 and the produced DMTS showed great inhibition to , which could be considered as effective biocontrol agents in further application.
Topics: Humans; Aspergillus flavus; Aflatoxins; Pseudomonas stutzeri; Phylogeny
PubMed: 36422962
DOI: 10.3390/toxins14110788 -
3 Biotech Feb 2023Toxic polycyclic aromatic hydrocarbons (PAHs) are often released into the environment during the combustion and processing of fossil fuels and are capable of causing...
UNLABELLED
Toxic polycyclic aromatic hydrocarbons (PAHs) are often released into the environment during the combustion and processing of fossil fuels and are capable of causing significant pollution to people and the environment. One of the representative substances of PAHs is phenanthrene, which is often studied as a model compound for PAHs treatment. In this study, we compared the results of transcriptome analysis of in two different culture conditions under phenanthrene-induced culture (test group) and glucose-induced culture (control group), and analysed the key enzymatic mechanisms of in the biodegradation of phenanthrene. In our experiments, the transcriptome results showed that a total of 380 genes were more than twofold differentially expressed in the test group, of which 187 genes were significantly up-regulated in expression under Phenanthrene induction. Among the 380 differentially expressed genes, 90 genes were involved in Phenanthrene biodegradation, mainly including genes involved in biometabolism, cellular chemotaxis, substrate transport, signal induction and other related processes. Based on the transcriptome sequence analysis of at the time of phenanthrene induction, a total of 25 dioxygenase genes were identified, and the related genes were mainly concentrated in two relatively concentrated clusters of PAHs biodegradation genes. The transcriptome analysis resulted in a complete set of enzyme genes related to the phenanthrene biodegradation pathway. The analysis of key enzymes led to the inference of a possible phenanthrene biodegradation pathway: the salicylic acid degradation pathway. The results of this study provide a theoretical basis for in situ remediation of PAHs-contaminated environments using .
SUPPLEMENTARY INFORMATION
The online version contains supplementary material available at 10.1007/s13205-023-03473-7.
PubMed: 36718409
DOI: 10.1007/s13205-023-03473-7 -
Biotechnology Reports (Amsterdam,... Sep 2020Alginate is a group of water-soluble linear polysaccharides comprising of variable units of α-l-guluronic and β-d-mannuronic acid. The alginates are in high demand in...
Alginate is a group of water-soluble linear polysaccharides comprising of variable units of α-l-guluronic and β-d-mannuronic acid. The alginates are in high demand in biomedical, pharmaceutical and bioengineering applications. In the present study, we have isolated a strain of that has potential alginate synthesis. The biochemical and physiochemical characteristic including Carbazole assay, DSC, FTIR and H NMR were confirmed the alginate synthesis efficacy by . Evaluation of alginate for the removal of heavy metals such as Chromium, Cobalt and Lead showed that it effectively adsorbs heavy metals. Further analysis of gelling ability and cytotoxicity evaluation revealed that the alginate can be reconstituted as hydrogel and scaffold. Overall, our findings suggest that the strain may be used to produce alginate at commercial level that has the potential bioremediation and biomedical applications.
PubMed: 32874945
DOI: 10.1016/j.btre.2020.e00517