Spotlight
Biodegradation
BiodegradationDdvK, a Novel Major Facilitator Superfamily Transporter Essential for 5,5′-Dehydrodivanillate Uptake by Sphingobium sp. Strain SYK-6The bioengineering of bacteria to selectively transport and metabolize natural substrates into specific metabolites is a valuable strategy for industrial-scale chemical production. The uptake of many substrates into cells requires specific transport systems, and so the identification and characterization of transporter genes are essential for industrial applications. A number of bacterial major facilitator superfamily transporters of...
Environmental Microbiology
Environmental Microbiology | SpotlightMulti-omic Analyses of Extensively Decayed Pinus contorta Reveal Expression of a Diverse Array of Lignocellulose-Degrading EnzymesThe deconstruction of recalcitrant woody substrates is a central component of carbon cycling and forest health. Laboratory investigations have contributed substantially toward understanding the mechanisms employed by model wood decay fungi, but few studies have examined the physiological processes in natural environments. Herein, we identify the functional genes present in field samples of extensively decayed lodgepole pine (...
Environmental MicrobiologyFormate and Hydrogen as Electron Shuttles in Terminal Fermentations in an Oligotrophic Freshwater Lake SedimentIn the terminal steps of methane formation in freshwater lake sediments, fermenting bacteria cooperate syntrophically with methanogens and homoacetogens at minimum energy increments via interspecies electron transfer. The energy yields of the partner organisms in these cooperations have so far been calculated based mainly on in situ hydrogen partial pressures. In the present study, we also analyzed pools of formate as an...
Environmental MicrobiologyMicrobial Source Tracking Using Quantitative and Digital PCR To Identify Sources of Fecal Contamination in Stormwater, River Water, and Beach Water in a Great Lakes Area of ConcernFecal contamination of recreational water poses a persistent and ongoing problem, particularly in areas of concern around the Great Lakes. The identification of the source(s) of fecal contamination is essential for safeguarding public health as well as guiding remediation efforts; however, fecal contamination may frequently be present at low levels and remain undetectable by certain methodologies. In this study, we utilized microbial...
Enzymology and Protein Engineering
Enzymology and Protein EngineeringBoosting Secretion of Extracellular Protein by Escherichia coli via Cell Wall PerturbationCell surface structure stabilization is important for extracellular secretion of proteins in Escherichia coli. As the main constituent of the cell wall, peptidoglycan contributes to cell structure robustness and stability. Here, we perturbed the peptidoglycan network by deleting dacA and dacB genes encoding d,...
Food Microbiology
Food MicrobiologyElevated Inactivation Efficacy of a Pulsed UVC Light-Emitting Diode System for Foodborne Pathogens on Selective Media and Food SurfacesIn 2013, the United Nations Environment Programme convened the Minamata Convention on Mercury, which prohibits trade in mercury-containing products in order to ensure human health. It will be effectuated in 2020; use of low-pressure mercury lamps will be discontinued and a new UV light source selected to replace the conventional technology. In this regard, UVC-LEDs have been developed and the fundamental inactivating effect has been...
Genetics and Molecular Biology
Genetics and Molecular BiologyFinR Regulates Expression of nicC and nicX Operons, Involved in Nicotinic Acid Degradation in Pseudomonas putida KT2440This study analyzed the influence of finR deletion on the transcriptomic profile of Pseudomonas putida KT2440. The FinR regulator is widely distributed but poorly studied in diverse proteobacteria. Here, we found 11 operons that potentially are regulated by FinR in KT2440. We further demonstrated that FinR played a positive role and cooperated with the NicR...
Genetics and Molecular Biology | SpotlightOpuF, a New Bacillus Compatible Solute ABC Transporter with a Substrate-Binding Protein Fused to the Transmembrane DomainThe high-affinity import of compatible solutes from environmental sources is an important aspect of the cellular defense of many bacteria and archaea against the harmful effects of high external osmolarity. The accumulation of these osmostress protectants counteracts high-osmolarity-instigated water efflux, a drop in turgor to nonphysiological values, and an undue increase in molecular crowding of the cytoplasm; they thereby foster...
Geomicrobiology
GeomicrobiologyA Novel Shewanella Isolate Enhances Corrosion by Using Metallic Iron as the Electron Donor with Fumarate as the Electron AcceptorShewanella spp. are frequently found on corroded metal structures. Their role in microbial influenced corrosion has been attributed mainly to their Fe(III)-reducing properties and, therefore, has been studied with the addition of an electron donor (lactate). Shewanella spp., however, can also use...
Invertebrate Microbiology
Invertebrate MicrobiologyEnhancement of Bacillus thuringiensis Cry1Ab and Cry1Fa Toxicity to Spodoptera frugiperda by Domain III Mutations Indicates There Are Two Limiting Steps in Toxicity as Defined by Receptor Binding and Protein StabilitySpodoptera frugiperda is the main maize pest in South and North America and also is an invasive pest in different African countries. However, it is poorly controlled by Bacillus thuringiensis Cry1A toxins expressed in transgenic crops, which effectively control other lepidopteran pests. In contrast...
Methods
MethodsMesophilic Sporeformers Identified in Whey Powder by Using Shotgun Metagenomic SequencingThe ability of sporeformers to remain dormant in a desiccated state is of concern from a safety and spoilage perspective in dairy powder. Traditional culturing techniques are slow and provide little information without further investigation. We describe the identification of mesophilic sporeformers present in powders produced over 1 year, using novel shotgun metagenomic sequencing. This method allows detection and identification of...
MethodsAutomated Microscopic Analysis of Metal Sulfide Colonization by Acidophilic MicroorganismsThe presented method for the assessment of mineral colonization allows accurate relative comparisons of the microbial colonization of metal sulfide concentrate particles in a time-resolved manner. Quantitative assessment of the mineral colonization development is important for the compilation of improved mathematical models for metal sulfide dissolution. In addition, deep-learning algorithms proved that axenic or mixed cultures of the...
Microbial Ecology
Microbial EcologyBroad Phylogenetic Diversity Associated with Nitrogen Loss through Sulfur Oxidation in a Large Public Marine AquariumEngineered aquatic systems such as aquaria and aquaculture facilities have large societal value. Ensuring the health of animals in these systems requires understanding how microorganisms contribute to chemical cycling and waste removal. Focusing on the largest seawater aquarium in the United States, we explore the microbial communities in specialized reactors designed to remove excess nitrogen through the metabolic activity of sulfur-...
Physiology
Physiology | SpotlightCyanophycin Synthesis Optimizes Nitrogen Utilization in the Unicellular Cyanobacterium Synechocystis sp. Strain PCC 6803We clarified the elusive biological function of cyanophycin in the nondiazotrophic cyanobacterium Synechocystis sp. PCC 6803. Cyanophycin is a dynamic carbon/nitrogen storage polymer (multi-arginyl-l-polyaspartate) that is conditionally present in most cyanobacteria and a few heterotrophic bacteria as cellular inclusion granules. Here, we show...
Physiology | SpotlightOrthologues of Bacillus subtilis Spore Crust Proteins Have a Structural Role in the Bacillus megaterium QM B1551 Spore ExosporiumWhen starved of nutrients, some bacterial species develop metabolically dormant spores that can persist in a viable state in the environment for several years. The outermost layers of spores are of particular interest since (i) these represent the primary site for interaction with the environment and (ii) the protein constituents may have biotechnological applications. The outermost layer, or exosporium, in...
PhysiologyComplex Iron Uptake by the Putrebactin-Mediated and Feo Systems in Shewanella oneidensisS. oneidensis is among the first- and the best-studied metal-reducing bacteria, with great potential in bioremediation and biotechnology. However, many questions regarding mechanisms closely associated with those applications, such as iron homeostasis, including iron uptake, export, and regulation, remain to be addressed. Here we show that Feo is a primary player in...
Plant Microbiology
Plant MicrobiologyVesicular Delivery of the Antifungal Antibiotics of Lysobacter enzymogenes C3The data presented here suggest a newly discovered function of outer membrane vesicles (OMV) that are produced from the outer membrane of the bacterial species Lysobacter enzymogenes strain C3. We show that these OMV can be released from the surface of the cells to deliver antibiotics to target fungal organisms as a mechanism of killing or growth inhibition....
Public and Environmental Health Microbiology
Public and Environmental Health Microbiology | SpotlightMethods for Handling Left-Censored Data in Quantitative Microbial Risk AssessmentThis study evaluates methods for handling data with low (10%) to severe (90%) left-censoring within an environmental microbiology context and demonstrates that some of these methods may be appropriate when using data containing concentrations below a limit of detection to estimate infection risks. Additionally, this study uses a skewed data set, which is an issue typically faced by environmental microbiologists.
Public and Environmental Health MicrobiologyA Q Fever Outbreak with a High Rate of Abortions at a Dairy Goat Farm: Coxiella burnetii Shedding, Environmental Contamination, and ViabilityThis work describes a 7-month follow-up of the excretion by different routes of Coxiella burnetii genotype SNP1/MST13 in a herd of goats that suffered high rate of abortions (81%), generating high environmental contamination. Some of the workers and visitors who accessed the farm were infected, with fever as the main symptom but a low incidence of pneumonia. 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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