Table of Contents
Spotlight
Minireview
MinireviewThe Ecology and Evolution of Amoeba-Bacterium InteractionsAmoebae are protists that have complicated relationships with bacteria, covering the whole spectrum of symbiosis. Amoeba-bacterium interactions contribute to the study of predation, symbiosis, pathogenesis, and human health. Given the complexity of their relationships, it is necessary to understand the ecology and evolution of their interactions. In this paper, we provide an updated review of the current understanding of amoeba-...
Environmental Microbiology
Environmental MicrobiologyDetoxification, Active Uptake, and Intracellular Accumulation of Chromium Species by a Methane-Oxidizing BacteriumM. capsulatus Bath is a well-characterized aerobic methane-oxidizing bacterium that has become a model system for biotechnological development of methanotrophs to perform useful reactions for environmental cleanup and for making valuable chemicals and biological products using methane gas. Interest in such technology has increased recently owing to increasing availability of low-cost methane from fossil and biological sources....
Environmental MicrobiologyAnnual Partitioning Patterns of Labyrinthulomycetes Protists Reveal Their Multifaceted Role in Marine Microbial Food WebsIncreasing evidence has shown that heterotrophic microeukaryotes are an important component in global marine ecosystems, while their diversity and ecological functions remain largely unknown. Without appropriately incorporating these organisms into the food web models, our current understanding of marine microbial community ecology is incomplete, which may further hamper broader studies of biogeochemistry and climate change. This study...
Environmental MicrobiologyKinetics of Bacterial Inactivation by Peroxynitric Acid in the Presence of Organic ContaminantsA good disinfectant for the human body should have various properties, such as strong bactericidal activity, harmlessness to living tissues, and resistance against biological fluids (or other organic contaminants). Peroxynitric acid (PNA) showed a bactericidal effect that was several tens up to several hundred times higher per unit of molarity than that of sodium hypochlorite and peracetic acid, which are used as general disinfectants...
Environmental MicrobiologyRuminal Degradation of Rumen-Protected Glucose Influences the Ruminal Microbiota and Metabolites in Early-Lactation Dairy CowsDairy cows in early lactation are prone to a negative energy balance because their dry matter intake cannot meet the energy requirements of lactation. Rumen-protected glucose is used as an effective feed additive to alleviate the negative energy balance of dairy cows in early lactation. However, one thing that is overlooked is that people often think that rumen-protected glucose is not degraded in the rumen, thus ignoring its impact on...
Environmental MicrobiologyBacillus thuringiensis Cry1Ab Domain III β-16 Is Involved in Binding to Prohibitin, Which Correlates with Toxicity against Helicoverpa armigera (Lepidoptera: Noctuidae)Helicoverpa armigera is a polyphagous pest that feeds on important crops worldwide. This insect pest is sensitive to different Cry1 toxins from Bacillus thuringiensis. In this study, we analyzed the potential role of PHB-2 as a Cry1 toxin receptor in comparison to CAD. We show that different Cry1...
Environmental MicrobiologyDissimilatory Nitrate Reduction to Ammonium (DNRA) and Denitrification Pathways Are Leveraged by Cyclic AMP Receptor Protein (CRP) Paralogues Based on Electron Donor/Acceptor Limitation in Shewanella loihica PV-4Some microbes utilize different dissimilatory nitrate reduction (DNR) pathways, including DNR to ammonia (DNRA) and denitrification pathways, for anaerobic respiration in response to ambient carbon/nitrogen ratio changes. Large-scale industrial nitrogen fixation and fertilizer application raise the concern of emission of N2O, a stable gas with potent global warming potential, as consequence of microbial respiration, thereby...
Environmental MicrobiologySoil Characteristics Constrain the Response of Microbial Communities and Associated Hydrocarbon Degradation Genes during PhytoremediationPolycyclic aromatic hydrocarbons (PAH) are a group of organic contaminants that pose a risk to ecosystems’ health. Phytoremediation is a promising biotechnology with the potential to restore PAH-contaminated soils. However, some limitations prevent it from becoming the remediation technology of reference, despite being environmentally friendlier than mainstream physicochemical alternatives. Recent reports suggest that the original soil...
Environmental MicrobiologyChasing Waterborne Pathogens in Antarctic Human-Made and Natural Environments, with Special Reference to Legionella spp.We comprehensively examined the localization of potential waterborne pathogens in the Antarctic human-made and natural aquatic environment with special focus on Legionella spp. Some potential pathogenic genera were detected with low relative abundance in the natural environment, but most detections of these genera occurred in the station. Through detailed community analysis of Legionella spp., we revealed that a...
Environmental Microbiology | SpotlightDynamics of Aspergillus fumigatus in Azole Fungicide-Containing Plant Waste in the Netherlands (2016–2017)Aspergillus fumigatus is consistently present independently on season at a high abundance in plant waste material throughout the sampling period. Our study confirmed that long-term storage sites of azole-containing decaying plant material can indeed be considered hot spots, which can sustain resistance development and maintenance in...
Environmental MicrobiologyIce-Binding Proteins Associated with an Antarctic Cyanobacterium, Nostoc sp. HG1The horizontal transfer of genes encoding ice-binding proteins (IBPs), proteins that confer freeze-thaw tolerance, has allowed many microorganisms to expand their ranges into polar regions. One group of microorganisms for which nothing is known about its IBPs is cyanobacteria. In this study, we identified a cyanobacterial IBP and showed that it was likely acquired from another bacterium, probably a planctomycete. We also showed that a...
Food Microbiology
Food MicrobiologyStress Resistance and Pathogenicity of Nonthermal-Plasma-Induced Viable-but-Nonculturable Staphylococcus aureus through Energy Suppression, Oxidative Stress Defense, and Immune-Escape MechanismsThe consumer demand for freshness and nutrition has accelerated the development of mild decontamination technologies. The incomplete killing of nonthermal (NT) treatments might induce pathogens to enter into a viable-but-nonculturable (VBNC) status as a survival strategy. The use of nonthermal plasma (NTP) as a novel food decontamination technology received increased attention in food industry during recent decades. Our previous work...
Genetics and Molecular Biology
Genetics and Molecular Biology | SpotlightUnique Properties of the Alpha-Helical DNA-Binding Protein KfrA Encoded by the IncU Incompatibility Group Plasmid RA3 and Its Host-Dependent Role in Plasmid MaintenanceAlpha-helical coiled-coil KfrA-type proteins are encoded by various broad-host-range low-copy-number conjugative plasmids. The DNA-binding protein KfrA encoded on the RA3 plasmid, a member of the IncU incompatibility group, oligomerizes, forms a complex with another plasmid-encoded, alpha-helical protein, KfrC, and interacts with the segrosome proteins IncC and KorB. The unique mode of KfrA dimer binding to the repetitive operator is...
Genetics and Molecular BiologyIdentification of Natural Mutations Responsible for Altered Infection Phenotypes of Salmonella enterica Clinical Isolates by Using Cell Line Infection ScreensSalmonella is a foodborne pathogen affecting over 200 million people and resulting in over 200,000 fatal cases per year. Its adhesion to and invasion into intestinal epithelial cells represent one of the first and key steps in the pathogenesis of salmonellosis. Still, around 35 to 40% of bacterial genes have no experimentally validated function, and their contribution to bacterial virulence, including adhesion and invasion,...
Geomicrobiology
GeomicrobiologyMolecular Evidence for an Active Microbial Methane Cycle in Subsurface Serpentinite-Hosted Groundwaters in the Samail Ophiolite, OmanSerpentinization of ultramafic rock can generate conditions favorable for microbial methane (CH4) cycling, including the abiotic production of hydrogen (H2) and possibly CH4. Systems of low-temperature serpentinization are geobiological targets due to their potential to harbor microbial life and ubiquity throughout Earth’s history. Biomass in fracture waters collected from the Samail Ophiolite of Oman, a...
Invertebrate Microbiology
Invertebrate MicrobiologyTermites Are Associated with External Species-Specific Bacterial CommunitiesAs is the case for all ecosystem engineers, termites impact their habitat by their activities, potentially affecting bacterial communities. Here, we studied three wood-feeding termite species and found that they influence the composition of the bacterial communities in their surrounding environment. Termite activities have positive effects on Rhizobiales and Actinobacteria abundance and negative effects on the...
Invertebrate MicrobiologyMicrobiome Variability across the Native and Invasive Ranges of the Ascidian Clavelina oblongaNonnative species destabilize coastal ecosystems and microbial symbionts may facilitate their spread by enhancing host survival and fitness. However, we know little of the microorganisms that live inside invasive species and whether they change as the host spreads to new areas. In this study, we investigated the microbial communities of an introduced ascidian (Clavelina oblonga) and tracked symbiont changes across locations...
Microbial Ecology
Microbial EcologyHigh Genetic Diversity in Flavobacterium psychrophilum Isolates from Healthy Rainbow Trout (Oncorhynchus mykiss) Farmed in the Same Watershed, Revealed by Two Typing MethodsThe bacterium Flavobacterium psychrophilum is a serious pathogen in many fish species, especially salmonids, that is responsible for considerable economic losses worldwide. In order to treat infections and to develop vaccines, the genetic diversity of this bacterium needs to be known. We assessed the genetic diversity of...
Microbial EcologyDilution-to-Stimulation/Extinction Method: a Combination Enrichment Strategy To Develop a Minimal and Versatile Lignocellulolytic Bacterial ConsortiumThe significance of our study mainly lies in the development of a combined top-down enrichment strategy (i.e., dilution to stimulation coupled to dilution to extinction) to build a minimal and versatile lignocellulolytic microbial consortium. We demonstrated that mainly two selectively enriched bacterial species (Pseudomonas sp. and Paenibacillus sp.) are required to drive the effective degradation of plant polymers....
Physiology
PhysiologyKey Enzymes for Anaerobic Lactate Metabolism in Geobacter sulfurreducensLactate is a microbial fermentation product as well as a source of carbon and electrons for microorganisms in the environment. Furthermore, lactate is a common amendment for stimulation of microbial growth in environmental biotechnology applications. However, anaerobic metabolism of lactate has been poorly studied for environmentally relevant microorganisms. Geobacter species are found in various environments and environmental...
PhysiologyRegulator RcsB Controls Prodigiosin Synthesis and Various Cellular Processes in Serratia marcescens JNB5-1RcsB is a two-component response regulator in the Rcs phosphorelay system, and it plays versatile regulatory functions in Enterobacteriaceae. However, information on the function of the RcsB protein in bacteria, especially in S. marcescens, remains limited. In this work, we illustrated...
PhysiologyThe Auxiliary NADH Dehydrogenase Plays a Crucial Role in Redox Homeostasis of Nicotinamide Cofactors in the Absence of the Periplasmic Oxidation System in Gluconobacter oxydans NBRC3293Nicotinamide cofactors NAD+ and NADP+ mediate redox reactions in metabolism. Gluconobacter oxydans, a member of the acetic acid bacteria, oxidizes glucose incompletely in the periplasmic space—outside the cell. This incomplete oxidation of glucose is independent of nicotinamide cofactors. However, if the periplasmic oxidation of glucose is...
Plant Microbiology
Plant Microbiology | SpotlightSpray Application of Nonpathogenic Fusaria onto Rice Flowers Controls Bakanae Disease (Caused by Fusarium fujikuroi) in the Next Plant GenerationWe demonstrated that a spray treatment of rice flowers with the spores of nonpathogenic fusaria mimicked the disease cycle of the seed-borne bakanae pathogen Fusarium fujikuroi and effectively suppressed the disease. Spray treatment of nonpathogenic fusaria reduced the degree of pathogen invasion of rice flowers and vertical transmission of the pathogen to the next...
Public and Environmental Health Microbiology
Public and Environmental Health Microbiology | SpotlightRepeated Oral Vaccination of Cattle with Shiga Toxin-Negative Escherichia coli O157:H7 Reduces Carriage of Wild-Type E. coli O157:H7 after ChallengeThe bacterium E. coli O157:H7 causes foodborne disease in humans that can lead to bloody diarrhea, kidney failure, vascular damage, and death. Healthy cattle are the main source of this human pathogen. Reducing E. coli O157:H7 in cattle will reduce human disease. Using a randomized comparison, a...
Public and Environmental Health Microbiology | SpotlightRetrotransposon-Based Blood Meal Analysis of Nymphal Deer Ticks Demonstrates Spatiotemporal Diversity of Borrelia burgdorferi and Babesia microti ReservoirsWhite-footed mice are thought to be the most important reservoir host for the deer tick-transmitted pathogens that cause Lyme disease and human babesiosis because they are the primary host for immature ticks. Transmission would be reduced, however, if ticks feed on deer, which are not capable of infecting ticks with either pathogen. By directly measuring whether ticks had fed on either mice or deer using a new quantitative PCR (qPCR)...
Masthead
