Table of Contents
Spotlight
Biodegradation
BiodegradationMhpA Is a Hydroxylase Catalyzing the Initial Reaction of 3-(3-Hydroxyphenyl)Propionate Catabolism in Escherichia coli K-12Phenylpropionate and its hydroxylated derivatives resulted from lignin degradation ubiquitously exist on the Earth. A number of bacterial strains have the ability to grow on 3HPP, one of the above derivatives. The hydroxylation was thought to be the initial and vital step for its aerobic catabolism via the meta pathway. The significance of our research is the functional identification and characterization of the purified 3HPP 2...
BiodegradationA Bph-Like Nitroarene Dioxygenase Catalyzes the Conversion of 3-Nitrotoluene to 3-Methylcatechol by Rhodococcus sp. Strain ZWL3NTNitroarenes are synthetic molecules widely used in the chemical industry. Microbial degradation of nitroarenes has attracted extensive attention, not only because this class of xenobiotic compounds is recalcitrant in the environment but also because the microbiologists working in this field are curious about the evolutionary origin and process of the nitroarene dioxygenases catalyzing the initial reaction in the catabolism. In contrast...
Environmental Microbiology
Environmental MicrobiologyA Comprehensive Account of Escherichia coli Sequence Type 131 in Wastewater Reveals an Abundance of Fluoroquinolone-Resistant Clade A StrainsST131 is a global pathogen. This clone causes urinary tract infections and is frequently isolated from human sources. However, little is known about ST131 from environmental sources. With the widely reported increase in antibiotic concentrations found in wastewater, there is additional selection pressure for the emergence of antibiotic-resistant ST131 in this niche. The unbiased screening approach reported herein revealed that...
Environmental MicrobiologyLipopolysaccharide Stimulates the Growth of Bacteria That Contribute to Ruminal AcidosisGram-negative bacteria contain lipopolysaccharide (LPS) coating their thin peptidoglycan cell wall. The presence of LPS has been suggested to be associated with a metabolic disorder of cattle—ruminal acidosis—through affecting ruminal bacteria. Ruminal acidosis could reduce feed intake and milk production and increase the incidence of diarrhea, milk fat depression, liver abscesses, and laminitis. However, how LPS affects bacteria...
Environmental Microbiology | SpotlightCasimicrobium huifangae gen. nov., sp. nov., a Ubiquitous “Most-Wanted” Core Bacterial Taxon from Municipal Wastewater Treatment PlantsThe activated sludge process is the most widely applied biotechnology and is one of the best ecosystems to address microbial ecological principles. Yet, the cultivation of core bacteria and the exploration of their physiology and ecology are limited. In this study, the core and novel bacterial taxon C. huifangae was cultivated and characterized. This study revealed that C. huifangae functioned as an important module...
Enzymology and Protein Engineering
Enzymology and Protein EngineeringComputationally Aided Discovery of LysEFm5 Variants with Improved Catalytic Activity and StabilityBroad-spectrum antibiotics can indiscriminately kill most bacteria, including commensal species that are a part of the normal human flora. This can potentially lead to the proliferation of drug-resistant bacteria upon elimination of competing species and to unwanted autoimmune effects in patients. Bacteriophage-derived lysin proteins are an alternative to conventional antibiotics that have coevolved alongside specific bacterial hosts....
Evolutionary and Genomic Microbiology
Evolutionary and Genomic MicrobiologyPhylogenomic Analyses of Members of the Widespread Marine Heterotrophic Genus Pseudovibrio Suggest Distinct Evolutionary Trajectories and a Novel Genus, Polycladidibacter gen. nov.The genus Pseudovibrio is commonly associated with marine invertebrates, which are essential for ocean health and marine nutrient cycling. Traditionally, the phylogeny of the genus has been based on 16S rRNA gene analysis. The use of the 16S rRNA gene or any other single marker gene for robust phylogenetic placement has recently been questioned. We used a large set of marker genes from all available Pseudovibrio...
Evolutionary and Genomic Microbiology | SpotlightYeast Viral Killer Toxin K1 Induces Specific Host Cell Adaptions via Intrinsic Selection PressureThe killer phenotype in Saccharomyces cerevisiae relies on the cytoplasmic persistence of two RNA viruses. In contrast to bacterial toxin producers, killer yeasts necessitate a specific immunity mechanism against their own toxin because they bear the same receptor populations as sensitive cells. Although the killer phenomenon is highly abundant and has a crucial...
Food Microbiology
Food MicrobiologyThe Locus of Heat Resistance Confers Resistance to Chlorine and Other Oxidizing Chemicals in Escherichia coliChlorine treatments are used in water and wastewater sanitation; the resistance of Escherichia coli to chlorine is thus of concern to public health. We show that a genetic island termed the locus of heat resistance (LHR) protects E. coli not only against heat but also against chlorine and other...
Genetics and Molecular Biology
Genetics and Molecular BiologyLysR-Type Transcriptional Regulator MetR Controls Prodigiosin Production, Methionine Biosynthesis, Cell Motility, H2O2 Tolerance, Heat Tolerance, and Exopolysaccharide Synthesis in Serratia marcescensSerratia marcescens, a Gram-negative bacterium, is found in a wide range of ecological niches and can produce several secondary metabolites, including prodigiosin, althiomycin, and serratamolide. Among them, prodigiosin shows diverse functions as an immunosuppressant, antimicrobial, and anticancer agent. However, the regulatory mechanisms behind prodigiosin synthesis...
Genetics and Molecular Biology | SpotlightAntimicrobial Activity of, and Cellular Pathways Targeted by, p-Anisaldehyde and Epigallocatechin Gallate in the Opportunistic Human Pathogen Pseudomonas aeruginosaEssential oils (EOs) are plant-derived products that have long been exploited for their antimicrobial activities in medicine, agriculture, and food preservation. EOs represent a promising alternative to conventional antibiotics due to their broad-range antimicrobial activity, low toxicity to human commensal bacteria, and capacity to kill microorganisms without promoting resistance. Despite the progress in the understanding of the...
Invertebrate Microbiology
Invertebrate MicrobiologyStable Establishment of Cardinium spp. in the Brown Planthopper Nilaparvata lugens despite Decreased Host FitnessIn this study we established a Cardinium-infected N. lugens line that possessed complete maternal transmission. Cardinium had a widespread distribution in tissues of N. lugens, and this infection decreased the fecundity and hatching rate of the host. Our findings emphasize the...
Microbial Ecology
Microbial EcologyAlterations of the Viable Ileal Microbiota of the Gut Mucosa-Lymph Node Axis in Pigs Fed Phytase and Lactic Acid-Treated CerealsA host’s diet largely determines the gut microbial composition and therefore may influence bacterial translocation into ICLNs. Due to its importance for cell metabolism, the intestinal phosphorus availability, which was modified here by phytase and LA treatment of cereals, affects the intestinal microbiota. Previous studies mainly focused on bacteria in the lumen. The novelty of this work resides mainly in that we...
Microbial Ecology | SpotlightRelationship between the Gut Microbiome and Energy/Nutrient Intake in a Confined Bioregenerative Life Support SystemThe gut microbiome shows individual specificity and is affected by sex, environment, and diet; gut microbiome imbalance is related to cancer, cardiovascular diseases, and autoimmune diseases. Astronauts are faced with a challenging environment and limited diet in outer space. Recent studies indicate that the gut microbiome is altered in space simulators and space, but what happens to intestinal microorganisms when astronauts cohabitate...
Physiology
PhysiologyThe Impact of pH on Clostridioides difficile Sporulation and PhysiologyClostridioides difficile is an anaerobic bacterium that causes gastrointestinal disease. C. difficile forms dormant spores which can survive harsh environmental conditions, allowing their spread to new hosts. In this study, we determine how intestinally relevant pH conditions impact...
Plant Microbiology
Plant Microbiology | SpotlightMetabolic and Genomic Traits of Phytobeneficial Phenazine-Producing Pseudomonas spp. Are Linked to Rhizosphere Colonization in Arabidopsis thaliana and Solanum tuberosumRhizosphere colonization is crucial for plant growth promotion and biocontrol by antibiotic-producing Pseudomonas spp. This colonization process relies on different bacterial determinants which partly remain to be uncovered. In this study, we combined a metabolic and a genomic approach to decipher new rhizosphere colonization determinants which could improve our understanding of this process in Pseudomonas spp. Using...
Public and Environmental Health Microbiology
Public and Environmental Health MicrobiologyUV Inactivation of Rotavirus and Tulane Virus Targets Different Components of the VirionsUV irradiation is becoming common for disinfection in water treatment plants, but little is known about the effectiveness of this treatment for enteric RNA viruses. Here, we observed that 220-nm UV irradiation was efficacious against rotavirus (RV) and Tulane virus (TV). UV irradiation at 254 nm inactivated TV to a greater extent than RV. Additional assays showed that UV irradiation compromised different portions of the RV and TV life...
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