Spotlight
Biodegradation
BiodegradationMcbG, a LysR Family Transcriptional Regulator, Activates the mcbBCDEF Gene Cluster Involved in the Upstream Pathway of Carbaryl Degradation in Pseudomonas sp. Strain XWY-1Pseudomonas sp. strain XWY-1 is a carbaryl-degrading strain that utilizes carbaryl as the sole carbon and energy source for growth. The functional genes involved in the degradation of carbaryl have already been reported.
Biotechnology
BiotechnologyLaboratory Evolution and Reverse Engineering of Clostridium thermocellum for Growth on Glucose and FructoseC. thermocellum is an important candidate for sustainable and cost-effective production of bioethanol through consolidated bioprocessing. In addition to unsurpassed cellulose deconstruction, industrial application and fundamental studies would benefit from improvement of glucose and fructose consumption.
Environmental Microbiology
Environmental Microbiology | SpotlightSeafloor Incubation Experiment with Deep-Sea Hydrothermal Vent Fluid Reveals Effect of Pressure and Lag Time on Autotrophic Microbial CommunitiesDiverse microbial communities drive biogeochemical cycles in Earth’s ocean, yet studying these organisms and processes is often limited by technological capabilities, especially in the deep ocean. In this study, we used a novel marine microbial incubator instrument capable of in situ experimentation to investigate microbial primary producers at deep-sea hydrothermal vents.
Environmental MicrobiologyTwo PAAR Proteins with Different C-Terminal Extended Domains Have Distinct Ecological Functions in Myxococcus xanthusThe type VI secretion system (T6SS) is a bacterial cell contact-dependent weapon capable of delivering protein effectors into neighboring cells. The PAAR protein is located at the top of the nanomachine and carries an effector for delivery.
Environmental MicrobiologyComparison of Strategies for Isolating Anaerobic Bacteria from the Porcine IntestineThis work determined that using a combination of isolation methods is necessary to increase the diversity of bacteria recovered from the intestines of monogastric mammals. Direct plating methods have traditionally been used to isolate enteric bacteria, and recent methods (e.g., diffusion methods [i.e., ichip] or differential isolation of endospore-forming bacteria) have been suggested to be superior at increasing diversity, including...
Environmental MicrobiologyIdentification of a Diguanylate Cyclase That Facilitates Biofilm Formation on Electrodes by Shewanella oneidensis MR-1Bioelectrochemical systems (BESs) have attracted wide attention owing to their utility in sustainable biotechnology processes, such as microbial fuel cells and electrofermentation systems. In BESs, electrochemically active bacteria (EAB) form biofilms on electrode surfaces, thereby serving as effective catalysts for the interconversion between chemical and electric energy.
Environmental Microbiology | SpotlightMetagenomic Insights into the Metabolic and Ecological Functions of Abundant Deep-Sea Hydrothermal Vent DPANN ArchaeaDPANN archaea show high distribution in the hydrothermal system, although they display small genome size and some incomplete biological processes. Exploring their metabolism is helpful to understand how such small forms of life adapt to this unique environment and what ecological roles they play.
Environmental MicrobiologyA Type VI Secretion System Facilitates Fitness, Homeostasis, and Competitive Advantages for Environmental Adaptability and Efficient Nicotine BiodegradationMixtures of various pollutants and the coexistence of numerous species of organisms are usually found in adverse environments. Concerning biodegradation of nitrogen-heterocyclic contaminants, the scientific community has commonly focused on screening functional enzymes that transform pollutants into intermediates of attenuated toxicity or for primary metabolism. Here, we identified dual roles of the T6SS effector TseN in...
Food Microbiology
Food Microbiology | SpotlightDietary Inulin Increases Lactiplantibacillus plantarum Strain Lp900 Persistence in Rats Depending on the Dietary-Calcium LevelSynbiotics combine probiotics with prebiotics to synergistically elicit a health benefit in the consumer. Previous studies have shown that prebiotics can selectively stimulate the growth in the intestine of specific bacterial strains.
Food MicrobiologyVegetable-Derived Carbapenemase-Producing High-Risk Klebsiella pneumoniae ST15 and Acinetobacter baumannii ST2 Clones in Japan: Coexistence of blaNDM-1, blaOXA-66, blaOXA-72, and an AbaR4-Like Resistance Island in the Same SampleCarbapenemase-producing Gram-negative bacteria (CPGNB) cause severe health care-associated infections and constitute a major public health threat. Here, we investigated the genetic features of CPGNB isolated from fresh vegetable samples in Japan and found CPGNB, including Klebsiella pneumoniae and ...
Food MicrobiologyPrevalence of Listeria Species on Food Contact Surfaces in Washington State Apple Packinghouses...Since 2014, fresh apples have been linked to outbreaks and recalls associated with postharvest cross-contamination with the foodborne pathogen L. monocytogenes. These situations drive both public health burden and economic loss and underscore the need for continued scrutiny of packinghouse management to eliminate potential Listeria spp. niches.
Food Microbiology | SpotlightVolatile Organic Compound-Mediated Antifungal Activity of Pichia spp. and Its Effect on the Metabolic Profiles of Fermentation CommunitiesFermentation of food occurs within communities of interacting species. The importance of microbial interactions in shaping microbial structure and metabolic performance to optimize the traditional fermentation process has long been emphasized, but the interaction mechanisms remain unclear.
Food MicrobiologyTranscriptome Analysis of Listeria monocytogenes Exposed to Beef Fat Reveals Antimicrobial and Pathogenicity Attenuation MechanismsListeria monocytogenes is a bacterial pathogen known for its ability to survive and thrive under adverse environments and, as such, its control poses a significant challenge, especially with the trend of minimally processed and ready-to-eat foods. This work investigated the effectiveness of fatty acids from various sources as natural antimicrobials against...
Genetics and Molecular Biology
Genetics and Molecular BiologyThe Tail-Specific Protease Is Important for Legionella pneumophila To Survive Thermal Stress in Water and inside AmoebaeLp is a major cause of nosocomial and community-acquired pneumonia. Lp is found in water systems, including hot water distribution systems. Heat treatment is a method of disinfection often used to limit the presence of Lp in such systems; however, the benefit is usually short term, as Lp is able to quickly recolonize these systems.
Microbial Ecology
Microbial EcologySuccession of the Resident Soil Microbial Community in Response to Periodic InoculationsIntroducing beneficial microbes to the plant-soil system is an environmentally friendly approach to improve the crop yield and soil environment. Numerous studies have attempted to reveal the impacts of inoculation on the rhizosphere microbiome.
Microbial Ecology“Sifarchaeota,” a Novel Asgard Phylum from Costa Rican Sediment Capable of Polysaccharide Degradation and Anaerobic MethylotrophyThe exploration of deep marine sediments has unearthed many new lineages of microbes. The finding of this novel phylum of Asgard archaea is important, since understanding the diversity and evolution of Asgard archaea may inform also about the evolution of eukaryotic cells. The comparison of metabolic potentials of the Asgard archaea can help inform about selective pressures the lineages have faced during evolution.
Microbial EcologyContagious Antibiotic Resistance: Plasmid Transfer among Bacterial Residents of the Zebrafish GutTo understand how antibiotic resistance plasmids end up in human pathogens, it is crucial to learn how, where, and when they are transferred and maintained in members of bacterial communities such as the gut microbiome. To gain insight into the network of plasmid-mediated antibiotic resistance sharing in the gut microbiome, we investigated the transferability and maintenance of a multidrug resistance plasmid among the culturable...
Microbial EcologySelective Uptake of Pelagic Microbial Community Members by Caribbean Reef CoralsWe identify interactions between coral grazing behavior and the growth rates and cell abundances of pelagic microbial groups found surrounding a Caribbean reef. During incubation experiments with three reef corals, reductions in microbial cell abundance differed according to coral species and suggest specific coral or microbial mechanisms are at play.
Physiology
Physiology | SpotlightAdaptive Laboratory Evolution Restores Solvent Tolerance in Plasmid-Cured Pseudomonas putida S12: a Molecular AnalysisSustainable production of high-value chemicals can be achieved by bacterial biocatalysis. However, bioproduction of biopolymers and aromatic compounds may exert stress on the microbial production host and limit the resulting yield.
PhysiologyThe DUG Pathway Governs Degradation of Intracellular Glutathione in Aspergillus nidulansGlutathione (GSH) is a widely distributed tripeptide in both eukaryotes and prokaryotes. Owing to its very low redox potential, antioxidative character, and high intracellular concentration, GSH profoundly shapes the redox status of cells.
PhysiologyThe Genome Copy Number of the Thermophilic Cyanobacterium Thermosynechococcus elongatus E542 Is Controlled by Growth Phase and Nutrient AvailabilityThe present study revealed that the genome copy number (ploidy) status in the thermophilic cyanobacterium Thermosynechococcus E542 is regulated by growth phase and various environmental parameters to give us a window into understanding the role of polyploidy. An increased ploidy level is found to be associated with higher metabolic activity and increased vigor by acting as backup genetic information to compensate for damage to...
Plant Microbiology
Plant MicrobiologyBiosurfactants Produced by Phyllosphere-Colonizing Pseudomonads Impact Diesel Degradation but Not Colonization of Leaves of Gnotobiotic Arabidopsis thalianaMany leaf-colonizing bacteria produce surfactants and are able to degrade aliphatic compounds; however, whether surfactant production provides a competitive advantage during leaf colonization is unclear. Furthermore, it is unclear if leaf colonizers take advantage of the aliphatic compounds that constitute the leaf cuticle and cuticular waxes.
Plant MicrobiologyA Stringent-Response-Defective Bradyrhizobium diazoefficiens Strain Does Not Activate the Type 3 Secretion System, Elicits an Early Plant Defense Response, and Circumvents NH4NO3-Induced Inhibition of NodulationThe symbiotic N2 fixation carried out between prokaryotic rhizobia and legume plants performs a substantial contribution to the N cycle in the biosphere. This symbiotic association is initiated when rhizobia infect and penetrate the root hairs, which is followed by the growth and development of root nodules, within which the infective rhizobia are established and protected.
Plant MicrobiologyCandicidin Isomer Production Is Essential for Biocontrol of Cucumber Rhizoctonia Rot by Streptomyces albidoflavus W68This study reports that candicidin-like secondary metabolites produced by microbial cells in natural soil environments can effectively control soilborne fungal diseases, revealing a novel mechanism of microbial biocontrol agents. We demonstrated that the main antifungal activity and biocontrol activity of Streptomyces albidoflavus strain W68 are attributable to the...
Public and Environmental Health Microbiology
Public and Environmental Health MicrobiologyLinezolid Resistance Genes in Enterococci Isolated from Sediment and Zooplankton in Two Italian Coastal AreasLinezolid is one of the few antimicrobials available to treat severe infections due to drug-resistant Gram-positive bacteria; therefore, the emergence of linezolid-resistant enterococci carrying transferable resistance determinants is of great concern for public health. Linezolid resistance genes (cfr, optrA, and poxtA), often plasmid located, can be transmitted via horizontal gene transfer and have the...
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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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Dr. Harold L. Drake, Editor in Chief