Editorial
Spotlight
Biotechnology
BiotechnologyMutations in Peptidoglycan Synthesis Gene ponA Improve Electrotransformation Efficiency of Corynebacterium glutamicum ATCC 13869Metabolic engineering and synthetic biology are now the key enabling technologies for manipulating microorganisms to suit the practical outcomes desired by humankind. The introduction of exogenous DNA into cells is an indispensable step for this purpose. However, some microorganisms, including the important industrial workhorse Corynebacterium glutamicum, possess a...
Environmental Microbiology
Environmental Microbiology | SpotlightNatural Compounds and Their Analogues as Potent Antidotes against the Most Poisonous Bacterial ToxinThe long-lasting endopeptidase activity of BoNT is a critical biological activity inside the nerve cell, as it prompts proteolysis of the SNARE proteins, involved in the exocytosis of the neurotransmitter acetylcholine. Thus, the BoNT endopeptidase activity is an appropriate clinical target for designing new small-molecule antidotes against BoNT with the potential to reverse the paralysis syndrome of botulism. In principle, small-...
Environmental Microbiology | SpotlightEfflux Transporter ArsK Is Responsible for Bacterial Resistance to Arsenite, Antimonite, Trivalent Roxarsone, and MethylarseniteThe metalloid extrusion systems are very important bacterial resistance mechanisms. Each of the previously reported ArsB, Acr3, ArsP, ArsJ, and MSF1 transport proteins conferred only inorganic or organic arsenic/antimony resistance. In contrast, ArsK confers resistance to several inorganic and organic trivalent arsenicals and antimonials. The identification of the novel efflux transporter ArsK enriches our understanding of bacterial...
Environmental MicrobiologyCarbaryl as a Carbon and Nitrogen Source: an Inducible Methylamine Metabolic Pathway at the Biochemical and Molecular Levels in Pseudomonas sp. Strain C5ppThe degradation of xenobiotics plays a significant role in the environment to maintain ecological systems as well as to prevent the imbalance of biogeochemical cycles via carbon-nitrogen cycling. Carbaryl is the most widely used pesticide from the carbamate family. Pseudomonas sp. strain C5pp, capable of utilizing carbaryl as a carbon and nitrogen source for its growth, subsequently helps in complete remediation of carbaryl....
Environmental Microbiology | SpotlightElectrode Colonization by the Feammox Bacterium Acidimicrobiaceae sp. Strain A6Most studies on electrogenic microorganisms have focused on the most abundant heterotrophs, while other microorganisms also commonly present in electrode microbial communities, such as Actinobacteria strains, have been overlooked. The novel Acidimicrobiaceae sp. strain A6 (Actinobacteria) is an iron-reducing bacterium that can colonize the surface of anodes in sediments and is linked to electrical current...
Enzymology and Protein Engineering
Enzymology and Protein EngineeringImprovement of ST0452 N-Acetylglucosamine-1-Phosphate Uridyltransferase Activity by the Cooperative Effect of Two Single Mutations Identified through Structure-Based Protein EngineeringWe demonstrated that the enzymatic activity of a thermostable protein was over 4 times higher than that of the wild-type protein following substitution of a single amino acid, without affecting its thermostability. The three-dimensional structure of the improved mutant protein complexed with substrate was determined. The same overall structure and interaction between the substituted residue and the GlcNAc substrate as observed in the...
Food Microbiology
Food MicrobiologyBehavior of Foodborne Pathogens Listeria monocytogenes and Staphylococcus aureus in Mixed-Species Biofilms Exposed to BiocidesThis study demonstrates that foodborne pathogens can be established in mixed-species biofilms and that this can protect them from biocide action. The protection is not due to specific characteristics of the pathogen, here S. aureus and L. monocytogenes, but likely caused by specific members or...
Methods
MethodsEffective Soil Extraction Method for Cultivating Previously Uncultured Soil BacteriaBoth metagenomics and single-cell sequencing can detect unknown genes from uncultured microbial strains in environments, and either method may find the significant potential metabolites and roles of these strains. However, such gene/genome-based techniques do not allow detailed investigations that are possible with cultures. To solve this problem, various approaches for cultivation of uncultured bacteria have been developed, but there...
Methods | SpotlightFluorescent Proteins, Promoters, and Selectable Markers for Applications in the Lyme Disease Spirochete Borrelia burgdorferiGenetic manipulation of the Lyme disease spirochete B. burgdorferi remains cumbersome, despite significant progress in the field. The scarcity of molecular reagents available for use in this pathogen has slowed research efforts to study its unusual biology. Of interest, B. burgdorferi displays...
Microbial Ecology
Microbial EcologyRhizosphere Microbial Response to Multiple Metal(loid)s in Different Contaminated Arable Soils Indicates Crop-Specific Metal-Microbe InteractionsThe rhizosphere is the “hub” for plant-microbe interactions and an active region for exchange of nutrients and energy between soil and plants. In arable soils contaminated by mining activities, the rhizosphere may be an important barrier resisting metal uptake. Therefore, the responses of the rhizosphere microbiota to metal contamination involve important biogeochemical processes, which can affect metal bioavailability and thus impact...
Microbial EcologyUbiquity and Diversity of Complete Ammonia Oxidizers (Comammox)The discovery of complete ammonia oxidizers (comammox), which oxidize ammonia to nitrate via nitrite, refutes the century-old paradigm that nitrification requires the activity of two types of microbes and redefines a key process in the biogeochemical nitrogen cycle. Understanding the functional relationships between comammox and other nitrifiers is important for ecological studies on the nitrogen cycle. Therefore, the diversity and...
Microbial EcologyEffects of Antimicrobial Peptide GH12 on the Cariogenic Properties and Composition of a Cariogenic Multispecies BiofilmDental caries is one of the most prevalent chronic infectious diseases worldwide, with substantial economic and quality-of-life impacts. Streptococcus mutans has been considered the principal pathogen of dental caries. To combat dental caries, an antimicrobial peptide, GH12, was designed, and its antibacterial effects on planktonic...
Microbial EcologyResponse of the Anaerobic Methanotroph “Candidatus Methanoperedens nitroreducens” to Oxygen Stress“Candidatus Methanoperedens nitroreducens” is an anaerobic archaeon which couples the reduction of nitrate to the oxidation of methane. This microorganism is present in a wide range of aquatic environments and man-made ecosystems, such as paddy fields and wastewater treatment systems. In such environments, these archaea may experience regular oxygen exposure. However, “Ca. Methanoperedens nitroreducens” is able to...
Microbial Ecology | SpotlightA Simple In Vitro Gut Model for Studying the Interaction between Escherichia coli and the Intestinal Commensal Microbiota in Cecal MucusBoth commensal and pathogenic strains of Escherichia coli appear to colonize the mammalian intestine by interacting physically and metabolically with other members of the microbiota in the mucus layer that overlays the cecal and colonic epithelium. However, the use of animal models and the complexity of the mammalian gut make it difficult to isolate experimental...
Physiology
PhysiologyacI Actinobacteria Assemble a Functional Actinorhodopsin with Natively Synthesized RetinalMicrobes play critical roles in determining the quality of freshwater ecosystems, which are vital to human civilization. Because acI Actinobacteria are ubiquitous and abundant in freshwater lakes, clarifying their ecophysiology is a major step in determining the contributions that they make to nitrogen and carbon cycling. Without accurate knowledge of these cycles,...
Plant Microbiology
Plant MicrobiologyLavender Decline in France Is Associated with Chronic Infection by Lavender-Specific Strains of “Candidatus Phytoplasma solani”The etiology and main pathways for the spread of lavender decline, an infectious disease affecting French lavender production since the 1960s, have remained unclear, hampering the development of efficient control strategies. An extensive survey of lavender fields led to the conclusion that “Candidatus Phytoplasma solani” was chronically infecting declining lavenders...
Public and Environmental Health Microbiology
Public and Environmental Health MicrobiologyPrimary Colonizing Betaproteobacteriales Play a Key Role in the Growth of Legionella pneumophila in Biofilms on Surfaces Exposed to Drinking Water Treated by Slow Sand FiltrationProliferation of L. pneumophila in premise plumbing poses a public health threat. Extended water treatment using physicochemical and biofiltration processes, including slow sand filtration, at four surface water supplies in The Netherlands reduces the microbial growth potential of the treated water to a minimum level, and the distributed drinking water complies with...
Public and Environmental Health MicrobiologyAmentoflavone Ameliorates Streptococcus suis-Induced Infection In Vitro and In VivoThe widespread use of antibiotics in therapy and in the prevention of Streptococcus suis infection in the swine industry raises concerns for the emergence of a resistant strain. The use of antivirulence agents has potential benefits, mainly because of the reduced selective pressure for the development of bacterial resistance. In this study, we found that amentoflavone...
Public and Environmental Health MicrobiologyRisk Factors for Detection, Survival, and Growth of Antibiotic-Resistant and Pathogenic Escherichia coli in Household Soils in Rural BangladeshSoil may represent a direct source or act as an intermediary for the transmission of antibiotic-resistant and pathogenic Escherichia coli strains, particularly in low-income and rural settings. Thus, determining risk factors associated with detection, growth, and long-term survival of E. coli in...
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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