Spotlight
Biodegradation
BiodegradationPyrethroid Carboxylesterase PytH from Sphingobium faniae JZ-2: Structure and Catalytic MechanismPyrethroid pesticides are widely applied in agriculture and household; however, extensive use of these pesticides also causes serious environmental and health problems. The hydrolysis of pyrethroids by carboxylesterases is the major pathway of microbial degradation of pyrethroids, but the structure of carboxylesterases and its catalytic mechanism are still unknown. Carboxylesterase PytH from...
Biotechnology
Biotechnology | SpotlightExploiting the Diversity of Saccharomycotina Yeasts To Engineer Biotin-Independent Growth of Saccharomyces cerevisiaeThe reported metabolic engineering strategy to enable optimal growth in the absence of biotin is of direct relevance for large-scale industrial applications of S. cerevisiae. Important benefits of biotin prototrophy include cost reduction during the preparation of chemically defined industrial growth media as well as a lower susceptibility of biotin-prototrophic...
Biotechnology | SpotlightAdaptive Laboratory Evolution and Reverse Engineering of Single-Vitamin Prototrophies in Saccharomyces cerevisiaeMany strains of Saccharomyces cerevisiae, a popular platform organism in industrial biotechnology, carry the genetic information required for synthesis of biotin, thiamine, pyridoxine, para-aminobenzoic acid, pantothenic acid, nicotinic acid, and inositol. However, omission of these B vitamins typically leads to suboptimal growth. This study demonstrates that...
BiotechnologyDissecting the Polyhydroxyalkanoate-Binding Domain of the PhaF Phasin: Rational Design of a Minimized Affinity TagPolyhydroxyalkanoates (PHAs) are biocompatible, nontoxic, and biodegradable biopolymers with exceptional applications in the industrial and medical fields. The complex structure of the PHA granule can be exploited as a toolbox to display molecules of interest on their surface. Phasins, the most abundant group of proteins on the granule, have been employed as anchoring tags to obtain functionalized PHA beads for high-affinity...
Enzymology and Protein Engineering
Enzymology and Protein Engineering | SpotlightRedox Coenzyme F420 Biosynthesis in Thermomicrobia Involves Reduction by Stand-Alone Nitroreductase Superfamily EnzymesCoenzyme F420 is a redox cofactor of Archaea and Actinobacteria, as well as some Gram-negative bacteria. Its involvement in processes such as the biosynthesis of antibiotics, the degradation of xenobiotics, and asymmetric enzymatic reductions renders F420 of great relevance for biotechnology. Recently, a new biosynthetic step during the formation of F420 in Actinobacteria was...
Enzymology and Protein EngineeringThe Homogalacturonan Deconstruction System of Paenibacillus amylolyticus 27C64 Requires No Extracellular Pectin Methylesterase and Has Significant Industrial PotentialPectin is an important structural polysaccharide found in most plant cell walls. In the environment, pectin degradation is part of the decomposition process that turns over dead plant material and is important to organisms that feed on plants. Industrially, pectinases are used to improve the quality of fruit juices and can also be used to process coffee cherries or tea leaves. These enzymes may also prove useful in reducing the...
Evolutionary and Genomic Microbiology
Evolutionary and Genomic MicrobiologyWhole-Genome Comparisons of Staphylococcus agnetis Isolates from Cattle and ChickensStaphylococcus agnetis has been recently recognized as associated with disease in dairy cattle and meat-type chickens. The infections appear to be limited in cattle and systemic in broilers. This report details the molecular relationships between cattle and chicken isolates in order to understand how this recently recognized species infects different hosts with...
Food Microbiology
Food Microbiology | SpotlightA Bottom-Up Approach To Develop a Synthetic Microbial Community Model: Application for Efficient Reduced-Salt Broad Bean Paste FermentationHumans have mastered high-salinity fermentation techniques for bean-based fermented product preparation over thousands of years. High salinity was used to select the functional microbiota and conducted food fermentation production with unique flavor. Although a high-salinity environment is beneficial for suppressing harmful microbes in the open fermentation environment, the fermentation efficiency of functional microbes is partially...
Food MicrobiologyChinese Liquor Fermentation: Identification of Key Flavor-Producing Lactobacillus spp. by Quantitative Profiling with Indigenous Internal StandardsIn this study, we developed a novel strategy using indigenous internal standards to normalize the high-throughput amplicon sequencing results. We chose two Lactobacillus species as indigenous internal standards and characterized the absolute abundance of the bacterial community. Further, we identified Lactobacillus as the key flavor producer using quantitative microbiome profiling combined with multivariate statistics...
Food MicrobiologyF-Specific RNA Bacteriophages Model the Behavior of Human Noroviruses during Purification of Oysters: the Main Mechanism Is Probably Inactivation Rather than ReleaseThis study provides new data about the behavior of viruses in oysters under purification processes and about their elimination mechanism. First, a high correlation has been observed between F-specific RNA bacteriophages of subgroup II (FRNAPH-II) and norovirus (NoV) in oysters impacted by fecal contamination when both are detected using molecular approaches. Second, when using reverse transcription-quantitative PCR and culture to detect...
Food MicrobiologyImpact of Poultry Processing Operating Parameters on Bacterial Transmission and Persistence on Chicken Carcasses and Their Shelf LifeCulture-based and culture-independent approaches were utilized to reveal bacterial community changes on chicken carcasses at different processing steps and potential routes from the local processing environment. Current commercial processing effectively reduced bacterial loads on carcasses. Poultry processes have similar processes across facilities, but various processing arrangements and operating parameters could impact the bacterial...
Genetics and Molecular Biology
Genetics and Molecular BiologyAccR, a TetR Family Transcriptional Repressor, Coordinates Short-Chain Acyl Coenzyme A Homeostasis in Streptomyces avermitilisAcyl-CoA carboxylases play key roles in primary and secondary metabolism. However, the regulation of ACCase genes transcription in Streptomyces spp. remains unclear. Here, we demonstrated that AccR responded to intracellular acetyl-, propionyl-, and methylcrotonyl-CoA availability and mediated transcription of the genes related to production and assimilation of these compounds in S. avermitilis. When intracellular...
Invertebrate Microbiology
Invertebrate MicrobiologyUnraveling the Composition of Insecticidal Crystal Proteins in Bacillus thuringiensis: a Proteomics ApproachBacillus thuringiensis (Bt)-based biological insecticides are used extensively to control insect pests and vectors of human diseases. Bt-based products provide greater specificity and biosafety than broad-spectrum synthetic insecticides. The biological activity of this bacterium resides in spores and crystals comprising complex mixtures of toxic proteins. We developed...
Invertebrate MicrobiologyLegacy of a Butterfly’s Parental Microbiome in Offspring PerformanceResident bacterial communities are almost absent in larvae of butterflies and thus are unlikely to affect their host. In contrast, adult butterflies contain conspicuous amounts of bacteria. While the host plant and immune state of adult parental butterflies are known to affect offspring traits, it has been unclear whether also the parental microbiome imposes direct effects on the offspring. Here, we show that disturbance of the...
Invertebrate MicrobiologyRapid Gastrointestinal Passage May Protect Bombus terrestris from Becoming a True Host for Nosema ceranaeEmerging infectious diseases (EIDs) pose a major health threat to both humans and animals. EIDs include, for instance, those that have spread into hitherto naive populations. Recently, the honey bee-specific microsporidium Nosema ceranae has been detected by molecular methods in field samples of bumblebees. This detection of...
Invertebrate MicrobiologyTransovarial Transmission of Bacteriome-Associated Symbionts in the Cicada Pycna repanda (Hemiptera: Cicadidae)Cicadas establish an intimate symbiosis with microorganisms to obtain essential nutrients that are extremely deficient in host plant sap. Previous studies on bacterial communities of cicadas mainly focused on a few widely distributed species, but knowledge about mountain-habitat species is quite poor. We initially revealed the physical distribution of the primary symbionts “Ca. Sulcia” and “Ca. Hodgkinia” and the...
Microbial Ecology
Microbial EcologyEcology of Lactobacilli Present in Italian Cheeses Produced from Raw MilkThe microbiota is known to play a key role in the development of the organoleptic features of dairy products. Lactobacilli have been reported to represent one of the main components of the nonstarter bacterial population, i.e., bacteria that are not deliberately added to the milk, harbored by cheese, although the species-level composition of this microbial population has never been assessed in detail. In the present study, we applied a...
Microbial EcologyMultiple Stressors Determine Community Structure and Estimated Function of River Biofilm BacteriaFreshwater ecosystems such as rivers are of crucial importance for human well-being. However, human activities result in many stressors (e.g., toxic chemicals, increased water temperatures, and hydrological alterations) cooccurring in rivers and streams worldwide. Among the many organisms inhabiting rivers and streams, bacteria are ecologically crucial; they are placed at the base of virtually all food webs and they recycle the organic...
Microbial EcologyMicrobial Ecology of Atlantic Salmon (Salmo salar) Hatcheries: Impacts of the Built Environment on Fish Mucosal MicrobiotaAtlantic salmon, Salmo salar, is the most farmed marine fish worldwide, with an annual production of 2,248 million metric tons in 2016. Salmon hatcheries are increasingly changing from flowthrough toward recirculating aquaculture system (RAS) design to accommodate more control over production along with improved environmental sustainability due to lower impacts on...
Microbial Ecology | SpotlightRespiratory and Gut Microbiota in Commercial Turkey Flocks with Disparate Weight Gain Trajectories Display Differential Compositional DynamicsTurkey meat is an important source of animal protein, and the industry around its production contributes significantly to the agricultural economy. The microorganisms present in the gut of turkeys are known to impact bird health and flock performance. However, the respiratory microbiota in turkeys is entirely unexplored. This study has elucidated the microbiota of respiratory tracts of turkeys from two commercial flocks raised in...
Microbial EcologyA Mediterranean Diet Intervention Reduces the Levels of Salivary Periodontopathogenic Bacteria in Overweight and Obese SubjectsChanges in dietary behavior with increased adherence to a Mediterranean diet can determine a reduction of periodontopathogenic bacterial abundances in the saliva of overweight subjects with cardiometabolic risk due to an unhealthy lifestyle, without any change in individual energy intake, nutrient intake, and physical activity.
Public and Environmental Health Microbiology
Public and Environmental Health MicrobiologyHemoplasmas Are Endemic and Cause Asymptomatic Infection in the Endangered Darwin’s Fox (Lycalopex fulvipes)Mycoplasma haemocanis is enzootic in Darwin’s foxes. There is a higher M. haemocanis genetic diversity and prevalence in foxes than in sympatric dogs, although haplotypes are shared between the two carnivore species. There is an apparent tolerance of Darwin’s foxes to...
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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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