Authors: Rosario Palacio, Cecilia Cornejo, Verónica Seija...

Topics: Bacterial Typing Techniques; Comamonas; DNA, Bacterial

PubMed: 32730480
DOI: 10.4067/s0716-10182020000200147

Review

Authors: Yun-Hao Wang, Zhou Huang, Shuang-Jiang Liu...

Chemotaxis is an important physiological adaptation that allows many motile bacteria to orientate themselves for better niche adaptation. Chemotaxis is best understood in . Other representative bacteria, such as , species, , and , also have been deeply studied and systemically summarized. These bacteria belong to α-, γ-, ε-Proteobacteria, or Firmicutes. However, β-Proteobacteria, of which many members have been identified as holding chemotactic pathways, lack a summary of chemotaxis. , belonging to β-Proteobacteria, grows with and chemotactically responds to a range of aromatic compounds. This paper summarizes the latest research on chemotaxis towards aromatic compounds, mainly from investigations of and other species.

Topics: Bacterial Proteins; Chemotaxis; Comamonas testosteroni; Computational Biology; Genome, Bacterial; Genomics; Gram-Negative Bacterial Infections; Humans; Hydrocarbons, Aromatic; Signal Transduction

PubMed: 31159416
DOI: 10.3390/ijms20112701

Review

Authors: Michael P Ryan, Ludmila Sevjahova, Rachel Gorman...

spp. are non-fermenting Gram-negative bacilli. They were first discovered in 1894, and since then, twenty-four species have been characterized. The natural habitat of these bacteria is soil, wastewater/sludge, fresh water such as ponds and rivers, and the animal intestinal microbiome. They were also isolated from industrial settings, such as activated sludge and polluted soil, and from the hospital environment and clinical samples, such as urine, pus, blood, feces, and kidney. spp. are associated with environmental bioremediation and are considered an important environmental bacterium rather than a human pathogen. However, in the 1980s, they became a concern when several human infections associated with these species were reported. Here, the genus was examined in terms of its members, identification techniques, and pathogenicity. Seventy-seven infection cases associated with these microorganisms that have been discussed in the literature were identified and investigated in this project. All relevant information regarding year of infection, country of origin, patient information such as age, sex, underlying medical conditions if any, type of infection caused by the species, antibiotic susceptibility testing, treatment, and outcomes for the patient were extracted from case reports. The findings suggest that even though spp. are thought of as being of low virulence, they have caused harmful health conditions in many healthy individuals and even death in patients with underlying conditions. Antimicrobial treatment of infections associated with these species, in general, was not very difficult; however, it can become an issue in the future because some strains are already resistant to different classes of antibiotics. Therefore, these pathogens should be considered of such importance that they should be included in the hospital screening programs.

PubMed: 36145464
DOI: 10.3390/pathogens11091032

Authors: Xing Wang, Qing Xu, Kang Hu...

The accumulation of cadmium (Cd) in plants is strongly impacted by soil microbes, but its mechanism remains poorly understood. Here, we report the mechanism of reduced Cd accumulation in rice by coculture of and species. In pot experiments, inoculation with the coculture decreased Cd content in rice grain and increased the amount of nonbioavailable Cd in Cd-spiked soils. Fluorescence in situ hybridization and scanning electron microscopy detection showed that the coculture colonized in the rhizosphere and rice root vascular tissue and intercellular space. Soil metagenomics data showed that the coculture increased the abundance of sulfate reduction and biofilm formation genes and related bacterial species. Moreover, the coculture increased the content of organic matter, available nitrogen, and potassium and increased the activities of arylsulfatase, β-galactosidase, phenoloxidase, arylamidase, urease, dehydrogenase, and peroxidase in soils. In subsequent rice transcriptomics assays, we found that the inoculation with coculture activated a hypersensitive response, defense-related induction, and mitogen-activated protein kinase signaling pathway in rice. Heterologous protein expression in yeast confirmed the function of four Cd-binding proteins (HIP28-1, HIP28-4, BCP2, and CID8), a Cd efflux protein (BCP1), and three Cd uptake proteins (COPT4, NRAM5, and HKT6) in rice. Succinic acid and phenylalanine were subsequently proved to inhibit rice divalent Cd [Cd(II)] uptake and activate Cd(II) efflux in rice roots. Thus, we propose a model that the coculture protects rice against Cd stress via Cd immobilization in soils and reducing Cd uptake in rice. [Formula: see text] Copyright © 2023 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license.

Topics: Cadmium; Oryza; Enterobacter; Comamonas; Coculture Techniques; In Situ Hybridization, Fluorescence; Soil; Soil Pollutants

PubMed: 36366828
DOI: 10.1094/MPMI-09-22-0186-R

Review

Authors: Franziska Maria Feller, Johannes Holert, Onur Yücel...

Bile acids are surface-active steroid compounds with a C carboxylic side chain at the steroid nucleus. They are produced by vertebrates, mainly functioning as emulsifiers for lipophilic nutrients, as signaling compounds, and as an antimicrobial barrier in the duodenum. Upon excretion into soil and water, bile acids serve as carbon- and energy-rich growth substrates for diverse heterotrophic bacteria. Metabolic pathways for the degradation of bile acids are predominantly studied in individual strains of the genera , , and . Bile acid degradation is initiated by oxidative reactions of the steroid skeleton at ring A and degradation of the carboxylic side chain before the steroid nucleus is broken down into central metabolic intermediates for biomass and energy production. This review summarizes the current biochemical and genetic knowledge on aerobic and anaerobic degradation of bile acids by soil and water bacteria. In addition, ecological and applied aspects are addressed, including resistance mechanisms against the toxic effects of bile acids.

PubMed: 34442838
DOI: 10.3390/microorganisms9081759

Authors: Xiong Luo, Jiayi Guo, Yan Lan...

Antimony (Sb) is toxic to ecosystems and potentially to public health via its accumulation in the food chain. Bioavailability and toxicity of Sb have been reduced using various methods for the remediation of Sb-contaminated soil in most studies. However, Sb-contaminated soil remediation by microbial agents has been rarely evaluated. In this study, we evaluated the potential for the use of Comamonas testosteroni JL40 in the bioremediation of Sb-contamination. Strain JL40 immobilized more than 30 % of the Sb(III) in solution and oxidized over 18 % to Sb(V) for detoxification. Meanwhile, strain JL40 responds to Sb toxicity through such as Sb efflux, intracellular accumulation, biofilm production, and scavenging of reactive oxygen species (ROS), etc. The results of the pot experiment showed the average Sb content of the brown rice was decreased by 59.1%, 38.8%, and 48.4%, for 1.8, 50, and 100 mg/kg Sb spiked soils, respectively. In addition, the results of plant, soil enzyme activity, and rice agronomic trait observations showed that the application of strain JL40 could maintain the health of plants and soil and improve rice production. The single-step and sequential extraction of Sb from rhizosphere soil showed that strain JL40 also plays a role in Sb immobilization and oxidation in the soil environment. During rice potted cultivation, bacterial community analysis and plate counting showed that the strain JL40 could still maintain 10 CFU/g after 30 days of inoculation. With phenotypic and differential proteomics analysis, strain JL40 conferred Sb(III) tolerance by a combination of immobilization, oxidation, efflux and scavenging of ROS, etc. Our study demonstrates the application of Sb-immobilizing and oxidizing bacteria to lower soil Sb and reduce accumulation of Sb in rice. Our results provide guidance for bacterial remediation of Sb-contaminated soil.

Topics: Soil; Antimony; Comamonas testosteroni; Biodegradation, Environmental; Ecosystem; Reactive Oxygen Species; Soil Pollutants

PubMed: 37356310
DOI: 10.1016/j.envint.2023.108040

Authors: Lauren C O'Connor, Woo Kyu Kang, Paula Vo...

Emerging evidence suggests the microbiome critically influences the onset and progression of neurodegenerative diseases; however, the identity of neuroprotective bacteria and the molecular mechanisms that respond within the host remain largely unknown. We took advantage of well characterized nervous system and ability to eat uni-bacterial diets to determine how metabolites and neuroprotective molecules from single species of bacteria suppress degeneration of motor neurons. We found significantly protects against degeneration induced by overexpressing a key regulator of axon degeneration, TIR-1/SARM1. Genetic analyses and metabolomics reveal protects against neurodegeneration by providing sufficient Vitamin B12 to activate METR-1/MTR methionine synthase in the intestine, which then lowers toxic levels of homocysteine in TIR-1-expressing animals. Defining a molecular pathway between and neurodegeneration adds significantly to our understanding of gut-brain interactions and, given the prominent role of homocysteine in neurodegenerative disorders, reveals how such a bacterium could protect against disease.

PubMed: 39605655
DOI: 10.1101/2024.11.20.622298

Authors: Gang Huang, Sui Wang, Juexin Wang...

BACKGROUND

Bile reflux can cause inflammation, gastric mucosa atrophy, and diseases such as stomach cancer. Alkaline bile flowing back into the stomach affects the intragastric environment and can alter the gastric bacterial community. We sought to identify the characteristics of the stomach mucosal microbiota in patients with bile reflux.

METHODS

Gastric mucosal samples were collected from 52 and 40 chronic gastritis patients with and without bile reflux, respectively. The bacterial profile was determined using 16S rRNA gene analysis.

RESULTS

In the absence of H. pylori infection, the richness (based on the Sobs and Chao1 indices; P <0.05) and diversity (based on Shannon indices; P <0.05) of gastric mucosa microbiota were higher in patients with bile reflux patients than in those without. There was a marked difference in the microbiota structure between patients with and without bile reflux (ANOSIM, R=0.058, P=0.011). While the genera, , , , , , , and were enriched in patients with bile reflux, the genera, , , and , were enriched in those without bile reflux.

CONCLUSION

Our results demonstrate that bile reflux significantly alters the composition of the gastric microbiota.

Topics: Bile Reflux; Gastric Mucosa; Gastritis; Helicobacter Infections; Helicobacter pylori; Humans; Microbiota; RNA, Ribosomal, 16S

PubMed: 36159635
DOI: 10.3389/fcimb.2022.940687

Authors: Lorena Fernández-Cabezón, Beatriz Galán, José L García...

A new biotechnological process for the production of testosterone (TS) has been developed to turn the model strain Mycobacterium smegmatis suitable for TS production to compete with the current chemical synthesis procedures. We have cloned and overexpressed two genes encoding microbial 17β-hydroxysteroid: NADP 17-oxidoreductase, from the bacterium Comamonas testosteroni and from the fungus Cochliobolus lunatus. The host strains were M. smegmatis wild type and a genetic engineered androst-4-ene-3,17-dione (AD) producing mutant. The performances of the four recombinant bacterial strains have been tested both in growing and resting-cell conditions using natural sterols and AD as substrates respectively. These strains were able to produce TS from sterols or AD with high yields. This work represents a proof of concept of the possibilities that offers this model bacterium for the production of pharmaceutical steroids using metabolic engineering approaches.

Topics: 17-Hydroxysteroid Dehydrogenases; Ascomycota; Comamonas testosteroni; Gene Expression; Metabolic Engineering; Metabolic Networks and Pathways; Mycobacterium smegmatis; Recombinant Proteins; Testosterone

PubMed: 27860310
DOI: 10.1111/1751-7915.12433

Authors: Lijin An, Xiong Luo, Minghan Wu...

Antimony, like arsenic, is a toxic metalloid widely distributed in the environment. Microbial detoxification of antimony has recently been identified. Here we describe a novel bacterial P-type antimonite (Sb(III))-translocating ATPase from the antimony-mining bacterium Comamonas testosterone JL40 that confers resistance to Sb(III). In a comparative proteomics analysis of strain JL40, an operon (ant operon) was up-regulated by Sb(III). The ant operon includes three genes, antR, antC and antA. AntR belongs to the ArsR/SmtB family of metalloregulatory proteins that regulates expression of the ant operon. AntA belongs to the P family of the P-type cation-translocating ATPases. It has both similarities to and differences from other members of the P subfamily and appears to be the first identified member of a distinct subfamily that we designate P. Expression AntA in E. coli AW3110 (Δars) conferred resistance to Sb(III) and reduced the intracellular concentration of Sb(III) but not As(III) or other metals. Everted membrane vesicles from cells expressing antA accumulated Sb(III) but not As(III), where uptake in everted vesicles reflects efflux from cells. AntC is a small protein with a potential Sb(III) binding site, and co-expression of AntC with AntA increased resistance to Sb(III). We propose that AntC functions as an Sb(III) chaperone to AntA, augmenting Sb(III) efflux. The identification of a novel Sb(III)-translocating ATPase enhances our understanding of the biogeochemical cycling of environmental antimony by bacteria.

Topics: Adenosine Triphosphatases; Antimony; Comamonas testosteroni; Escherichia coli; P-type ATPases

PubMed: 33254899
DOI: 10.1016/j.scitotenv.2020.142393