Spotlight
Biodegradation
Biodegradation | SpotlightRapid, Parallel Identification of Catabolism Pathways of Lignin-Derived Aromatic Compounds in Novosphingobium aromaticivoransThe identification of the genes involved in specific biochemical transformations is a key step in predicting microbial function from nucleic acid sequences and in engineering microbes to endow them with new functions. We have shown that new techniques for transposon mutagenesis can dramatically simplify this process and enable the rapid identification of genes in uncharacterized pathways. These techniques provide the necessary scale to...
BiodegradationSteroid Degradation in Comamonas testosteroni TA441: Identification of Metabolites and the Genes Involved in the Reactions Necessary before D-Ring CleavageStudies on representative steroid degradation bacteria Rhodococcus equi (Nocardia restrictus) and Comamonas testosteroni were initiated more than 50 years ago primarily to obtain materials for steroid drugs. A recent study showed...
BiodegradationOxidative Damage Control during Decay of Wood by Brown Rot Fungus Using Oxygen RadicalsWood is one of the largest pools of carbon on Earth, and its decomposition is dominated in most systems by fungi. Wood-degrading fungi specialize in extracting sugars bound within lignin, either by removing lignin first (white rot) or by using Fenton-generated reactive oxygen species (ROS) to “loosen” wood cell walls, enabling selective sugar extraction (brown rot). Although white rot lignin-degrading pathways are well characterized,...
Biotechnology
Biotechnology | SpotlightEngineering Pseudochelin Production in Myxococcus xanthusIn this study, an enzyme for imidazoline formation in pseudochelin biosynthesis was identified. Evidence for the involvement of this enzyme in the postulated reaction was obtained after in vitro reconstitution. Furthermore, the function of this enzyme was demonstrated in vivo by transferring the corresponding gene into the bacterium Myxococcus xanthus...
Environmental Microbiology
Environmental MicrobiologyGenome Analysis, Metabolic Potential, and Predatory Capabilities of Herpetosiphon llansteffanense sp. nov.Predatory bacteria are able to kill and consume other microbes and are therefore of interest as potential sources of new antimicrobial substances for applications in the clinic. “Wolf pack” predators kill prey by secreting antimicrobial substances into their surroundings, and those substances can kill prey organisms independently of the predatory cells. The genus ...
Environmental Microbiology | SpotlightBlame It on the Metabolite: 3,5-Dichloroaniline Rather than the Parent Compound Is Responsible for the Decreasing Diversity and Function of Soil MicroorganismsPesticide toxicity on soil microorganisms is an emerging issue in pesticide risk assessment, dictated by the pivotal role of soil microorganisms in ecosystem services. However, the focus has traditionally been on parent compounds, while transformation products (TPs) are largely overlooked. We tested the hypothesis that TPs can be major contributors to the soil microbial toxicity of pesticides using iprodione and its main TP, 3,5-...
Enzymology and Protein Engineering
Enzymology and Protein Engineering | SpotlightBiochemical Characterization of CYP505D6, a Self-Sufficient Cytochrome P450 from the White-Rot Fungus Phanerochaete chrysosporiumPhanerochaete chrysosporium is a white-rot fungus whose metabolism of lignin, aromatic pollutants, and lipids has been most extensively studied. This fungus harbors 154 cytochrome P450-encoding genes in the genome. As evidenced in this study, P. chrysosporium CYP505D6, a fused protein of P450 and...
Food Microbiology
Food MicrobiologyStress Resistance Development and Genome-Wide Transcriptional Response of Escherichia coli O157:H7 Adapted to Sublethal Thymol, Carvacrol, and trans-CinnamaldehydeThe present study was designed to understand transcriptomic changes and the potential development of direct and cross-resistance in essential oil (EO)-adapted Escherichia coli O157:H7. The results demonstrated altered growth behaviors of E. coli O157:H7 during adaptation in sublethal thymol,...
Food MicrobiologyA Vegetable Fermentation Facility Hosts Distinct Microbiomes Reflecting the Production EnvironmentFermented vegetables play a major role in global food systems and are widely consumed by various global cultures. In this study, we investigated an industrial facility that produces spontaneous fermented sauerkraut without the aid of starter cultures. This provides a unique system to explore and track the origins of an “in-house” microbiome in an industrial environment. Raw vegetables and the surfaces on which they are handled were...
Genetics and Molecular Biology
Genetics and Molecular BiologyIdeR, a DtxR Family Iron Response Regulator, Controls Iron Homeostasis, Morphological Differentiation, Secondary Metabolism, and the Oxidative Stress Response in Streptomyces avermitilisIron is essential to almost all organisms, but in the presence of oxygen, iron is both poorly available and potentially toxic. Streptomyces species are predominantly present in soil where the environment is complex and fluctuating. So far, the mechanism of iron homeostasis in Streptomyces spp....
Genetics and Molecular BiologyTranscriptional Studies on a Streptomyces clavuligerus oppA2 Deletion Mutant: N-Acetylglycyl-Clavaminic Acid Is an Intermediate of Clavulanic Acid BiosynthesisThe oppa2 gene encodes an oligopeptide permease essential for the production of clavulanic acid. A transcriptomic analysis of S. clavuligerus ΔoppA2::aac in comparison to the parental strain S. clavuligerus ATCC 27064 is reported. The lack of OppA2 results in different...
Genetics and Molecular BiologyGenome Editing Method for the Anaerobic Magnetotactic Bacterium Desulfovibrio magneticus RS-1Magnetotactic bacteria (MTB) are a group of organisms that form intracellular nanometer-scale magnetic crystals though a complex process involving lipid and protein scaffolds. These magnetic crystals and their lipid membranes, termed magnetosomes, are model systems for studying bacterial cell biology and biomineralization and are potential platforms for biotechnological applications. Due to a lack of genetic tools and unculturable...
Genetics and Molecular BiologyCoordinated Biosynthesis of the Purine Nucleoside Antibiotics Aristeromycin and Coformycin in ActinomycetesARM and COF are well known for their prominent biological activities and unusual chemical structures; however, the logic of their biosynthesis has long been poorly understood. Actually, the new insights into the ARM and COF pathway will not only enrich the biochemical repertoire for interesting enzymatic reactions but may also lay a solid foundation for the combinatorial biosynthesis of this group of antibiotics via a target-directed...
Genetics and Molecular BiologyPhage-Antibiotic Synergy via Delayed LysisPhage-antibiotic synergy (PAS) has been reported for a decade, but the underlying mechanism has never been vigorously investigated. This study shows the presence of PAS from a variety of phage-bacterium-antibiotic pairings. We show that increased phage production resulted directly from a lysis delay caused by the relative shortage of holin in filamented bacterial hosts in the presence of sublethal concentrations of stress-inducing...
Methods
MethodsA PCR-Based Method for Distinguishing between Two Common Beehive Bacteria, Paenibacillus larvae and Brevibacillus laterosporus16S rRNA gene sequencing in bacteria has long been held as the gold standard for typing bacteria and, for the most part, is an excellent method of taxonomically identifying different bacterial species. However, the high level of 16S rRNA sequence similarity of some published strains of P. larvae and B....
Microbial Ecology
Microbial EcologyMetabolic Interactions of a Chain Elongation MicrobiomeCarbon chain elongation means the conversion of short-chain volatile fatty acids to medium-chain carboxylates, such as n-caproate and n-caprylate with electron donors under anaerobic condition. This bio-reaction can both expand the resource of valuable biochemicals and broaden the utilization of low-grade organic residues in a sustainable biorefinery context....
Physiology
PhysiologyThe Complete Pathway for Thiosulfate Utilization in Saccharomyces cerevisiaeThe complete pathway of thiosulfate assimilation in baker's yeast is determined. The finding reveals the extensive overlap between sulfate and thiosulfate assimilation. Rhodanese is the only additional enzyme for thiosulfate utilization. The common presence of rhodanese in most organisms, including Bacteria,...
Physiology | SpotlightRegulatory Networks Governing Methionine Catabolism into Volatile Organic Sulfur-Containing Compounds in Clonostachys roseaMethionine shuttles organic nitrogen and plays a central role in nitrogen metabolism. Exogenous Met strongly induces the expression of ARO8-2 and PDC, represses the expression of STR3, and generates volatile organic sulfur-containing compounds via the Ehrlich and demethiolation pathways. In this study, we used genetic, bioinformatic, and metabolite-based analyses to confirm that transcriptional control of the...
Plant Microbiology
Plant MicrobiologyPhosphodiesterase EdpX1 Promotes Xanthomonas oryzae pv. oryzae Virulence, Exopolysaccharide Production, and Biofilm FormationBacteria utilize c-di-GMP as a second messenger to regulate various biological functions. The synthesis and degradation of c-di-GMP are catalyzed by GGDEF domains and an EAL or HD-GYP domain, respectively. Multiple genes encoding these domains are often found in one bacterial strain. For example, in the genome of X. oryzae pv. oryzae PXO99A, 26 genes encoding proteins containing these domains were identified....
Plant MicrobiologyPriming of Plant Growth Promotion by Volatiles of Root-Associated Microbacterium spp.In the past decade, various studies have described the effects of microbial volatiles on other (micro)organisms in vitro, but their broad-spectrum activity in vivo and the mechanisms underlying volatile-mediated plant growth promotion have not been addressed in detail. Here, we revealed that volatiles from root-associated bacteria of the genus ...
Public and Environmental Health Microbiology
Public and Environmental Health MicrobiologyTransfer of Enteric Viruses Adenovirus and Coxsackievirus and Bacteriophage MS2 from Liquid to Human SkinEnteric viruses (viruses that infect the gastrointestinal tract) are responsible for most water-transmitted diseases. They are shed in high concentrations in the feces of infected individuals, persist for an extended period of time in water, and are highly infective. Exposure to contaminated water directly (through ingestion) or indirectly (for example, through hand-water contacts followed by hand-to-mouth contacts) increases the risk...
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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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