Spotlight
Biotechnology
Biotechnology | SpotlightThe PlyB Endolysin of Bacteriophage vB_BanS_Bcp1 Exhibits Broad-Spectrum Bactericidal Activity against Bacillus cereus Sensu Lato IsolatesOrganisms of the Bacillus cereus sensu lato lineage are ubiquitous in the environment and are responsible for toxin-mediated infections ranging from severe food poisoning (B. cereus sensu stricto) to anthrax (Bacillus...
BiotechnologyToxoflavin Produced by Burkholderia gladioli from Lycoris aurea Is a New Broad-Spectrum FungicideHuman fungal infections are a growing problem associated with increased morbidity and mortality. Moreover, a growing number of antifungal-resistant fungal isolates have been reported over the past decade. Thus, the need for novel antifungal agents is imperative. In this study, we show that an endophytic bacterium, Burkholderia gladioli, isolated from the medicinal...
BiotechnologyEmbedding Bacillus velezensis NH-1 in Microcapsules for Biocontrol of Cucumber Fusarium WiltBacillus species are often used for the biocontrol of various plant pathogens, but the control efficiency of Bacillus is usually unstable in field experiments. To improve the control efficiency of Bacillus, in this study, microcapsules of Bacillus velezensis strain NH-1 were prepared using different wall materials (sodium alginate, chitosan...
Environmental Microbiology
Environmental Microbiology | SpotlightStress-Responsive Alternative Sigma Factor SigB Plays a Positive Role in the Antifungal Proficiency of Bacillus subtilisBiological control using beneficial bacteria (PGPRs) represents an attractive and environment-friendly alternative to pesticides for controlling plant diseases. Different PGPR Bacillus species produce potent biofungicides and stimulate plant defense responses against phytopathogenic fungi. However, very little is known about how PGPRs recognize phytopathogens and process the antifungal response. Here, we report how...
Environmental MicrobiologySpatiotemporal Dynamics of Free-Living and Particle-Associated Vibrio Communities in the Northern Chinese Marginal SeasThe dynamics of Vibrio communities have been shown in many marine habitats that are close to land, including estuary or harbor areas. Here, we investigated the spatiotemporal dynamics of Vibrio populations in the northern Chinese marginal seas, spanning a wide spatial scale. We showed that the abundances of the Vibrio population in the present study were higher than those in most previously studied areas and...
Environmental MicrobiologyZinc Toxicity and Iron-Sulfur Cluster Biogenesis in Escherichia coliZinc toxicity has been implicated in causing various human diseases. High concentrations of zinc can also inhibit bacterial cell growth. However, the underlying mechanism has not been fully understood. Here, we report that zinc overload in Escherichia coli cells inhibits iron-sulfur cluster biogenesis by targeting specific iron-sulfur cluster assembly proteins....
Environmental MicrobiologyLow Temperature and Neutral pH Define “Candidatus Nitrotoga sp.” as a Competitive Nitrite Oxidizer in Coculture with Nitrospira defluvii“Ca. Nitrotoga” is a NOB of high environmental relevance, but physiological data exist for only a few representatives. Initially, it was detected in specialized niches of low temperature and low nitrite concentrations, but later on, its ubiquitous distribution revealed its critical role for N removal in engineered systems like WWTPs. In this study, we analyzed the competition between Nitrotoga and Nitrospira...
Environmental MicrobiologyTwo Novel Bacteriophages Improve Survival in Galleria mellonella Infection and Mouse Acute Pneumonia Models Infected with Extensively Drug-Resistant Pseudomonas aeruginosaIn this study, two novel P. aeruginosa phages, Bϕ-R656 and Bϕ-R1836, were evaluated in vitro, in silico, and in vivo for therapeutic efficacy and safety as an alternative antibacterial agent to control XDR-PA strains collected from pneumonia patients. Both phages exhibited potent bacteriolytic activity and greatly improved survival in...
Environmental MicrobiologyPopulation Structure and Morphotype Analysis of “Candidatus Accumulibacter” Using Fluorescence In Situ Hybridization-Staining-Flow CytometryAs one group of the most important functional phosphorus removal organisms, “Candidatus Accumulibacter,” affiliated with the Rhodocyclus group of the Betaproteobacteria, is a widely recognized and studied PAO in the field of biological wastewater treatment. The morphotypes and population structure of clade-level “Candidatus Accumulibacter” were studied through novel FISH-staining-flow cytometry, which...
Environmental MicrobiologyThe Indoor-Air Microbiota of Pig Farms Drives the Composition of the Pig Farmers’ Nasal Microbiota in a Season-Dependent and Farm-Specific MannerThe airborne microbiota of pig farms poses a potential health hazard and impacts both livestock and humans working in this environment. Therefore, a more thorough understanding of the microbiota composition and dynamics in this setting is needed. This study was of a prospective design (12 months) and used samples from different sites. This means that the microbiota of air, animals (pigs), and humans was simultaneously investigated. Our...
Enzymology and Protein Engineering
Enzymology and Protein EngineeringConversion of Mevalonate 3-Kinase into 5-Phosphomevalonate 3-Kinase by Single Amino Acid MutationsIsoprenoid is the largest family of natural compounds, including important bioactive molecules such as vitamins, hormones, and natural medicines. The mevalonate pathway is a target for metabolic engineering because it supplies precursors for isoprenoid biosynthesis. Mevalonate 3-kinase is an enzyme involved in the modified mevalonate pathway specific to limited species of thermophilic archaea. Replacement of a single amino acid residue...
Enzymology and Protein Engineering | SpotlightA Lytic Polysaccharide Monooxygenase from a White-Rot Fungus Drives the Degradation of Lignin by a Versatile PeroxidaseThe enzymatic biodegradation of structural polysaccharides is affected by the degree of delignification of lignocellulose during the white-rot fungal decay process. The lignin matrix decreases accessibility to the substrates for LPMOs. H2O2 has been studied as a cosubstrate for LPMOs, but the formation and utilization of H2O2 in the reactions still represent an intriguing focus of current...
Food Microbiology
Food MicrobiologyTargeted and Repetitive Chromosomal Integration Enables High-Level Heterologous Gene Expression in Lactobacillus caseiLactic acid bacteria (LAB), including Lactobacillus casei, have the potential for overexpression of heterologous proteins, such as bioactive molecules and enzymes. However, traditional genetic tools for expression of these proteins show genetic instability or low yields of the desired product. In this study, we provide a procedure for repetitive integration of genes...
Food MicrobiologySurface Layer of Lactobacillus helveticus MIMLh5 Promotes Endocytosis by Dendritic CellsBeneficial microbes may positively affect host physiology at various levels, e.g., by participating in immune system maturation and modulation, boosting defenses and dampening reactions, thus affecting the whole homeostasis. As a consequence, the use of probiotics is increasingly regarded as suitable for more extended applications for health maintenance, not only microbiota balancing. This implies a deep knowledge of the mechanisms and...
Food MicrobiologyPrebiotic Supplementation of In Vitro Fecal Fermentations Inhibits Proteolysis by Gut Bacteria, and Host Diet Shapes Gut Bacterial Metabolism and Response to InterventionDietary protein intake is high in Western populations, which could result in potentially harmful metabolites in the gut from proteolysis. In an in vitro fermentation model, the addition of prebiotics reduced the negative consequences of high protein levels. Supplementation with a prebiotic resulted in a reduction of proteolytic metabolites in the model. A difference was seen in protein fermentation between omnivore and...
Genetics and Molecular Biology
Genetics and Molecular BiologyMethionine Limitation Impairs Pathogen Expansion and Biofilm Formation CapacityNew antibiotics that attack novel targets are needed to circumvent widespread resistance to conventional drugs. Bacterial anabolic pathways, such as the enzymes for biosynthesis of the essential amino acid methionine, have been proposed as potential targets. However, the eligibility of enzymes in these pathways as drug targets is unclear because metabolites might be acquired from the environment to overcome inhibition. We investigated...
Geomicrobiology
GeomicrobiologyGrowth Kinetics, Carbon Isotope Fractionation, and Gene Expression in the Hyperthermophile Methanocaldococcus jannaschii during Hydrogen-Limited Growth and Interspecies Hydrogen TransferHyperthermophilic methanogens and H2-producing heterotrophs are collocated in high-temperature subseafloor environments, such as petroleum reservoirs, mid-ocean ridge flanks, and hydrothermal vents. Abiotic flux of H2 can be very low in these environments, and there is a gap in our knowledge about the origin of CH4 in these habitats. In the hyperthermophile...
Methods
MethodsDegradation of Fungal MicroRNAs Triggered by Short Tandem Target Mimics Is via the Small-RNA-Degrading NucleaseThe development and application of STTM technology to block miR-like RNAs in M. robertsii and A. flavus may allow for efficient generation of miR-like RNA mutants in various fungi, providing a powerful tool for functional genomics of small RNA molecules in fungi.
Microbial Ecology
Microbial EcologyDifferential Effects of Breed and Nursing on Early-Life Colonic Microbiota and Immune Status as Revealed in a Cross-Fostering Piglet ModelEarly-life gut microbiota and immune status are pivotal for postnatal growth. By using an interspecific cross-fostering piglet model, we find that change in nursing mother transiently reshapes preweaning colon microbiota and immune status, while breed shows persistent effects both pre- and postweaning. Piglets nursed by Meishan sows had lower Streptococcus suis counts...
Microbial EcologyRecovery of Fungal Cells from Air Samples: a Tale of Loss and GainThis work shed light on a significant issue regarding the loss of fungal spores when recovered from air samples using liquid medium and centrifugation to concentrate air particles before DNA extraction. We provide proof that the loss affects the overall fungal diversity of aerosols and that some taxa are differentially more affected than others. Furthermore, a laboratory experiment confirmed the environmental results obtained during...
Microbial Ecology | SpotlightMycobiome Profiles in Breast Milk from Healthy Women Depend on Mode of Delivery, Geographic Location, and Interaction with BacteriaDuring recent years, human breast milk has been documented as a potential source of bacteria for the newborn. Recently, we have reported the presence of fungi in breast milk from healthy mothers. It is well known that environmental and perinatal factors can affect milk bacteria; however, the impact on milk fungi is still unknown. The current report describes fungal communities (mycobiota) in breast milk samples across different...
Microbial Ecology | SpotlightFarm Stage, Bird Age, and Body Site Dominantly Affect the Quantity, Taxonomic Composition, and Dynamics of Respiratory and Gut Microbiota of Commercial Layer ChickensThe poultry industry is faced with numerous challenges associated with infectious diseases and suboptimal performance of flocks. As microbiome research continues to grow, it is becoming clear that poultry health and production performance are partly influenced by nonpathogenic symbionts that occupy different habitats within the bird. This study has defined the baseline composition and overlaps between respiratory and gut bacteria in...
Physiology
PhysiologyInfluence of Energy and Electron Availability on In Vivo Methane and Hydrogen Production by a Variant Molybdenum NitrogenaseA variant form of Mo nitrogenase catalyzes the conversion of CO2 and protons to the biofuels CH4 and H2. A constant supply of electrons and ATP is needed to drive these reduction reactions. The bacterium R. palustris generates ATP from light and has a versatile metabolism that makes it ideal for manipulating electron availability...
Plant Microbiology
Plant MicrobiologyInsight into the Bacterial Endophytic Communities of Peach Cultivars Related to Crown Gall Disease ResistanceAgrobacterium tumefaciens as the causal agent of peach crown gall disease can be controlled by planting resistant cultivars. This study profiles the endophytic bacteria in susceptible and resistant peach cultivars, advancing our understanding of the relationships between endophytic bacterial communities and peach crown gall disease, with potential implications for...
Public and Environmental Health Microbiology
Public and Environmental Health MicrobiologyRegulation of Iron Uptake by Fine-Tuning the Iron Responsiveness of the Iron Sensor FurIron is a fundamental metal ion for living organisms as it facilitates various biological processes. The ferric uptake regulator (Fur) protein controls iron homeostasis in various bacterial species. It is believed that Fur’s iron-dependent regulatory action is sufficient for it to function as an iron sensor. However, we now establish that the bacterial pathogen Salmonella enables Fur to properly reflect changes in surrounding...
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Applied and Environmental Microbiology® (AEM) publishes study results that make significant contributions to applied microbial research, basic microbial ecology research, and genetic and molecular investigations of microbial topics of practical value.
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