Table of Contents
Spotlight
Minireviews
MinireviewEncapsulation and Delivery of Therapeutic PhagesDelivery of therapeutic compounds to the site of action is crucial. While many chemical substances such as beta-lactam antibiotics can reach therapeutic levels in most parts throughout the human body after administration, substances of higher molecular weight such as therapeutic proteins may not be able to reach the site of action (e.g., an infection) and are therefore ineffective.
Minireview | SpotlightThe Symbiotic “All-Rounders”: Partnerships between Marine Animals and Chemosynthetic Nitrogen-Fixing BacteriaNitrogen fixation is a widespread metabolic trait in certain types of microorganisms called diazotrophs. Bioavailable nitrogen is limited in various habitats on land and in the sea and, accordingly, a range of plant, animal, and single-celled eukaryotes have evolved symbioses with diverse diazotrophic bacteria, with enormous economic and ecological benefits.
MinireviewThe Roseobacter-Group Bacterium Phaeobacter as a Safe Probiotic Solution for AquaculturePhaeobacter inhibens has been assessed as a probiotic bacterium for application in aquaculture. Studies addressing the efficacy and safety indicate that P. inhibens maintains it antagonistic activity against pathogenic vibrios in aquaculture live cultures (live feed and fish egg/larvae), while having no or a positive effect on the host organisms and a minor...
Biotechnology
BiotechnologySimultaneous Directed Evolution of Coupled Enzymes for Efficient Asymmetric Synthesis of l-PhosphinothricinThe traditional strategy to improve multienzyme-catalyzed reaction efficiencies may lead to enhanced single-enzyme catalytic efficiencies but may also result in the loss of coordination among enzymes. We describe a directed evolution strategy for an entire coupled-enzyme system to simultaneously enhance enzyme coordination and catalytic efficiency.
Environmental Microbiology
Environmental Microbiology | SpotlightBioelectrochemical Fixation of Nitrogen to Extracellular Ammonium by Pseudomonas stutzeriAmmonia greatly affects global ecology, agriculture, and the food industry. Diazotrophs with an enhanced capacity of extracellular NH4+ excretion have been proven to be more beneficial to the growth of microalgae and plants, whereas most previously reported diazotrophs produce intracellular organic nitrogen in the absence of chemical suppression and genetic manipulation.
Environmental MicrobiologyThe Organosulfur Compound Dimethylsulfoniopropionate (DMSP) Is Utilized as an Osmoprotectant by Vibrio SpeciesDMSP is present in the marine environment, produced in large quantities by marine phytoplankton as an osmoprotectant, and is an important component of the global geochemical sulfur cycle. This algal osmolyte has not been previously investigated for its role in marine heterotrophic bacterial osmotic stress response. Vibrionaceae species are marine species, many of...
Environmental MicrobiologyA Novel Antidipteran Bacillus thuringiensis Strain: Unusual Cry Toxin Genes in a Highly Dynamic Plasmid EnvironmentBacillus thuringiensis, a soil entomopathogenic bacterium, is at the base of many sustainable eco-friendly bioinsecticides. Hence stems the need to continually characterize insecticidal toxins.
Environmental MicrobiologyEnhancement of Nitrous Oxide Emissions in Soil Microbial Consortia via Copper Competition between Proteobacterial Methanotrophs and DenitrifiersProteobacterial methanotrophs—groups of microorganisms that utilize methane as a source of energy and carbon—have been known to utilize unique mechanisms to scavenge copper, namely, utilization of methanobactin, a polypeptide that binds copper with high affinity and specificity. Previously the possibility that copper sequestration by methanotrophs may lead to alteration of cuproenzyme-mediated reactions in denitrifiers and consequently...
Environmental MicrobiologyNo Endospore Formation Confirmed in Members of the Phylum ProteobacteriaBacterial endospore formation is an important process that allows the formation of dormant life forms called spores. Organisms able to sporulate can survive harsh environmental conditions for hundreds of years.
Environmental Microbiology | SpotlightMyxococcus xanthus Predation of Gram-Positive or Gram-Negative Bacteria Is Mediated by Different Bacteriolytic Mechanisms...Predation is an important survival strategy of the widespread myxobacteria, but it remains poorly understood on the mechanistic level. Without a basic understanding of how prey cell killing and consumption is achieved, it also remains difficult to investigate the role of predation for the complex myxobacterial lifestyle, reciprocal predator-prey relationships, or the impact of predation on complex bacterial soil communities.
Environmental MicrobiologyAspergillus fumigatus Cross-Resistance between Clinical and Demethylase Inhibitor Azole DrugsDue to the worldwide emergence of A. fumigatus azole resistance, this opportunistic pathogen poses a serious health threat, and therefore, it has been included in the watch list in the CDC publication Antibiotic Resistance Threats in the United States, 2019 (CDC, 2019). Azoles play a critical role in the control and management of fungal diseases, not only in...
Environmental Microbiology | SpotlightEvolution of Diverse Effective N2-Fixing Microsymbionts of Cicer arietinum following Horizontal Transfer of the Mesorhizobium ciceri CC1192 Symbiosis Integrative and Conjugative ElementSymbiotic N2 fixation is a key component of sustainable agriculture, and in many parts of the world legumes are inoculated with highly efficient strains of rhizobia to maximize fixed N2 inputs into farming systems. Symbiosis genes for Mesorhizobium spp. are often carried chromosomally within mobile gene clusters called ICEs.
Environmental MicrobiologyMethod for Measuring Phenotypic Colistin Resistance in Escherichia coli Populations from Chicken FlocksColistin (polymyxin E) is an antimicrobial with poor solubility in agar-based media, and therefore, broth microdilution is the only available method for determining phenotypic resistance. However, estimating colistin resistance in mixed Escherichia coli populations is laborious, since it requires individual colony isolation, identification, and susceptibility testing...
Environmental MicrobiologyAeromonas Species from Nonchlorinated Distribution Systems and Their Competitive Planktonic Growth in Drinking WaterThe occurrence of the bacterial genus Aeromonas in nonchlorinated drinking water in the Netherlands is regarded as an indication of elevated microbial regrowth in the distribution system. Identification of the prevalent species in 10 distribution systems by genotyping yielded seven different species, with A. rivuli, A. veronii, and A. sobria being the most dominant ones.
Enzymology and Protein Engineering
Enzymology and Protein EngineeringNew Family of Carbohydrate-Binding Modules Defined by a Galactosyl-Binding Protein Module from a Cellvibrio japonicus Endo-XyloglucanaseThis study reveals carbohydrate-binding module family 88 (CBM88) as a new family of galactose-binding protein modules, which are found in series with diverse microbial glycoside hydrolases, polysaccharide lyases, and carbohydrate esterases. The definition of CBM88 in the carbohydrate-active enzymes classification (http://www.cazy.org/CBM88.html) will significantly enable future microbial (...
Food Microbiology
Food MicrobiologyImplementation of ATP and Microbial Indicator Testing for Hygiene Monitoring in a Tofu Production Facility Improves Product Quality and Hygienic Conditions of Food Contact Surfaces: a Case StudyCleaning and sanitation are critical to maintaining safe and high-quality food production. Monitoring these activities is important to ensure proper execution of procedure and to assure compliance with regulatory guidelines.
Food MicrobiologyInfluence of Single Nitrogen Compounds on Growth and Fermentation Performance of Starmerella bacillaris and Saccharomyces cerevisiae during Alcoholic FermentationMixed fermentations combining non-Saccharomyces and S. cerevisiae strains are increasingly implemented in the wine sector, as they offer promising opportunities to diversify the flavor profile of end products. However, competition for nutrients between species can cause fermentation problems, which is a severe hindrance to the development of these approaches...
Food MicrobiologyStaphylococcal Enterotoxin Gene Cluster: Prediction of Enterotoxin (SEG and SEI) Production and of the Source of Food Poisoning on the Basis of vSaβ TypingBesides the infection properties in human and animals, S. aureus can produce different enterotoxins in food. The enterotoxins can cause vomiting and diarrhea, often involving many people.
Genetics and Molecular Biology
Genetics and Molecular BiologyYbeY Controls the Type III and Type VI Secretion Systems and Biofilm Formation through RetS in Pseudomonas aeruginosaPseudomonas aeruginosa causes a variety of acute and chronic infections in humans. The type III secretion system (T3SS) plays an important role in acute infection, and the type VI secretion system (T6SS) and biofilm formation are associated with chronic infections.
Genetics and Molecular BiologyA Viability Quantitative PCR Dilemma: Are Longer Amplicons Better?Viability quantitative PCR (v-qPCR) has evolved into a valuable, mainstream technique for determining the number of viable microorganisms in samples by qPCR. Amplicon length is known to be positively correlated with the ability to distinguish between live and dead bacteria but is negatively correlated with qPCR efficiency.
Invertebrate Microbiology
Invertebrate MicrobiologyHindgut Microbiota Reflects Different Digestive Strategies in Dung Beetles (Coleoptera: Scarabaeidae: Scarabaeinae)Dung beetles are a very important part of an ecosystem because of their role in the removal and decomposition of vertebrate dung. It has been suspected that symbiotic gut bacteria facilitate this role, a hypothesis that we have explored with high-throughput barcoding.
Invertebrate Microbiology | SpotlightCry75Aa (Mpp75Aa) Insecticidal Proteins for Controlling the Western Corn Rootworm, Diabrotica virgifera virgifera LeConte (Coleoptera: Chrysomelidae), Isolated from the Insect-Pathogenic Bacterium Brevibacillus laterosporusInsects feeding on roots of crops can damage the plant roots, resulting in yield loss due to poor water and nutrient uptake and plant lodging. In maize, the western corn rootworm (WCR) can cause severe damage to the roots, resulting in significant economic loss for farmers.
Microbial Ecology
Microbial EcologyBlastomyces dermatitidis Environmental Prevalence in Minnesota: Analysis and Modeling Using Soil Collected at Basal and Outbreak SitesUpon inhalation of spores from the fungus Blastomyces dermatitidis from the environment, humans and animals can develop the disease blastomycosis. Based on disease epidemiology, B. dermatitidis is known to be endemic in the United States and Canada around the Great Lakes and in the Ohio and...
Microbial EcologyInfluence of Spatial Scale on Structure of Soil Bacterial Communities across an Arctic LandscapeThe significance of this study is 3-fold. It investigated the influence of spatial scale on the soil bacterial community composition across a typical Arctic landscape and demonstrated that conclusions reached when examining the influence of specific environmental variables on bacterial community composition are dependent upon the spatial scales over which they are investigated.
Microbial EcologyRecovery of Methanotrophic Activity Is Not Reflected in the Methane-Driven Interaction Network after Peat MiningThe resilience and recovery of microorganisms from disturbances are often determined with regard to their activity and community composition/abundances. Rarely has the response of the network of interacting microorganisms been considered, despite accumulating evidence showing that microbial interaction modulates community functioning.
Microbial EcologyA Large Tn7-like Transposon Confers Hyperresistance to Copper in Pseudomonas syringae pv. syringaeCopper compounds have traditionally been used as standard bactericides in agriculture in the past few decades. However, the extensive use of copper has fostered the evolution of bacterial copper resistance mechanisms. Pseudomonas syringae is a plant-pathogenic bacterium used worldwide as a model to study plant-pathogen interactions.
Microbial EcologyArid Ecosystem Vegetation Canopy-Gap Dichotomy: Influence on Soil Microbial Composition and Nutrient Cycling Functional PotentialIncreasing aridity will drive a shift in desert vegetation and interspace gap (microsite) structure toward gap expansion. To evaluate the impact of gap expansion, we assess microsite effects on soil nutrients, microbiome community composition and functional capacity, and the potential of gap soils to serve as microbial reservoirs for plant root-associated microbiomes in an arid ecosystem.
Physiology
Physiologyl-Arabinose Induces the Formation of Viable Nonproliferating Spheroplasts in Vibrio choleraeVibrios spp. among other bacteria form transient cell wall-deficient forms as a response to different stresses and revert to proliferating rods when permissive conditions have been restored. Such cellular forms have been associated with antimicrobial tolerance, chronic infections, and environmental dispersion.
PhysiologyIntegrated Transcriptome Sequencing (RNA-seq) and Proteomic Studies Reveal Resource Reallocation towards Energy Metabolism and Defense in Skeletonema marinoi in Response to CO2 IncreaseRising atmospheric CO2 concentrations are causing ocean acidification with significant consequences for marine organisms. Chain-forming centric diatoms of Skeletonema is one of the most successful groups of eukaryotic primary producers with widespread geographic distribution.
Plant Microbiology
Plant MicrobiologyAgricultural Soil Management Practices Differentially Shape the Bacterial and Fungal Microbiomes of Sorghum bicolorWhile numerous studies show that farming practices can influence the soil microbiome, there are often conflicting results on how microbial diversity and activity respond to treatment. In addition, very little has been published on how the corresponding crop plant microbiome is impacted.
Public and Environmental Health Microbiology
Public and Environmental Health MicrobiologyThe Shared Resistome of Human and Pig Microbiota Is Mobilized by Distinct Genetic Elements...There is growing concern that antibiotic resistance genes could spread from the husbandry environment to human pathogens through dissemination mediated by mobile genetic elements. In this study, we investigated the contribution of mobile genetic elements to the abundance of highly prevalent antibiotic resistance genes found in commensal bacteria of both human and pig intestinal microbiota originating from the same region.
Public and Environmental Health MicrobiologyPlant-Scale Validation of Physical Heat Treatment of Poultry Litter Composts Using Surrogate and Indicator Microorganisms for Salmonella...Poultry litter compost, commonly used as a biological soil amendment, is subjected to a physical heat treatment in the industry setting to reduce pathogenic bacteria such as Salmonella and produce a dry product. According to the FDA Food Safety Modernization Act (FSMA) produce safety rule, the thermal process for poultry litter compost should be scientifically validated to satisfy the microbial standard requirement.
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