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Meeting Reviews
Meeting Review | SpotlightA Toxic Environment: a Growing Understanding of How Microbial Communities Affect Escherichia coli O157:H7 Shiga Toxin ExpressionEnterohemorrhagic Escherichia coli (EHEC) strains, including E. coli O157:H7, cause severe illness in humans due to the production of Shiga toxin (Stx) and other virulence factors. Because Stx is coregulated with lambdoid prophage induction, its expression is especially susceptible to environmental...
Meeting ReviewThe Intriguing Interaction of Escherichia coli with the Host Environment and Innovative Strategies To Interfere with Colonization: a Summary of the 2019 E. coli and the Mucosal Immune System MeetingThe third E. coli and the Mucosal Immune System (ECMIS) meeting was held at Ghent University in Belgium from 2 to 5 June 2019. It brought together an international group of scientists interested in mechanisms of colonization, host response, and vaccine development. ECMIS distinguishes itself from related meetings on these enteropathogens by providing a greater...
Meeting Presentations
Meeting PresentationCoimmunization with Two Enterotoxigenic Escherichia coli (ETEC) Fimbrial Multiepitope Fusion Antigens Induces the Production of Neutralizing Antibodies against Five ETEC Fimbriae (F4, F5, F6, F18, and F41)Enterotoxigenic Escherichia coli (ETEC)-associated postweaning diarrhea (PWD) is still a leading disease in recently weaned piglets. Vaccination is considered to be the most ideal and efficacious strategy for preventing PWD. Recently, a commercialized live monovalent F4 oral vaccine and a bivalent F4/F18 oral vaccine have been demonstrated to effectively protect...
Meeting PresentationApplication of a Novel Epitope- and Structure-Based Vaccinology-Assisted Fimbria-Toxin Multiepitope Fusion Antigen of Enterotoxigenic Escherichia coli for Development of Multivalent Vaccines against Porcine Postweaning DiarrheaETEC-associated postweaning diarrhea (PWD) causes significant economic losses to swine producers worldwide. Currently, there is no effective prevention against PWD. A vaccine that blocks ETEC fimbriae (K88 and F18) from attaching to host receptors and prevents enterotoxins from stimulating water hypersecretion in pig small intestinal epithelial cells can effectively protect against PWD and significantly improves pig health and well-...
Meeting PresentationPorcine Enterotoxigenic Escherichia coli Strains Differ in Their Capacity To Secrete Enterotoxins through Varying YghG LevelsEnterotoxigenic E. coli strains are a major health concern. Enterotoxins secreted by enterotoxigenic E. coli are crucial for diarrhea induction. Enterotoxin secretion levels differ between strains; however, it is currently unclear what drives these differences. The discrepancy in the production and...
Meeting PresentationPorcine and Bovine Forms of Lactoferrin Inhibit Growth of Porcine Enterotoxigenic Escherichia coli and Degrade Its Virulence FactorsCurrently, postweaning F4+ and F18+Escherichia coli infections in piglets are controlled by the use of antibiotics and zinc oxide, but the use of these antimicrobial agents most likely contributes to an increase in antibiotic resistance. Our work demonstrates that bovine and porcine lactoferrin can inhibit the growth of porcine enterotoxigenic...
Meeting PresentationVitamin K Analogs Influence the Growth and Virulence Potential of Enterohemorrhagic Escherichia coliEnterohemorrhagic E. coli (EHEC) can cause serious illness and deaths in humans by producing toxins that can severely damage our intestines and kidneys. There is currently no optimal treatment for EHEC infections, as antibiotics can worsen disease development. Consequently, the need for new treatment options is urgent. Environmental factors in our intestines can...
Biotechnology
BiotechnologyAntifungal Effects of Drimane Sesquiterpenoids Isolated from Drimys winteri against Gaeumannomyces graminis var. triticiMore than two billion tons of pesticides are used every year worldwide. An interesting sustainable alternative to control plant pathogens is the use of natural products obtained from plants, mainly medicinal plants that offer secondary metabolites important to human/animal health. In this study, we isolated and identified six pure drimane sesquiterpenoids obtained from the bark of...
BiotechnologyCandida glabrata Yap6 Recruits Med2 To Alter Glycerophospholipid Composition and Develop Acid pH Stress ResistanceThis study investigated the function of the Mediator tail subunit CgMed2 in C. glabrata under low-pH stress. The protein kinase CgYak1 activates CgYap6 for the recruitment of CgMed2, which in turn increases glycerophospholipid content and membrane integrity to confer low-pH stress tolerance. This study establishes a new link between...
Biotechnology | SpotlightUse of Flavin-Containing Monooxygenases for Conversion of Trimethylamine in Salmon Protein HydrolysatesEnzyme-based conversion of marine biomass to high-quality peptide ingredients leaves a distinct smell of “fish” caused by the presence of trimethylamine, which limits their economic potential. We suggest an enzymatic solution for converting trimethylamine to the odorless trimethylamine N-oxide as a novel strategy to improve the smell quality of marine protein hydrolysates. Following a systematic investigation of 45 putative...
BiotechnologyDisruption of the Oxidative Pentose Phosphate Pathway Stimulates High-Yield Production Using Resting Corynebacterium glutamicum in the Absence of External Electron AcceptorsThe widely used industrial workhorse C. glutamicum possesses a complex anaerobic metabolism under nongrowing conditions, and we demonstrate here that the PPP in resting C. glutamicum is a source of reducing power that can interfere with otherwise redox-balanced metabolic pathways and reduce yields...
Environmental Microbiology
Environmental MicrobiologyRevealing the Metabolic Flexibility of “Candidatus Accumulibacter phosphatis” through Redox Cofactor Analysis and Metabolic Network ModelingHere, we demonstrate how microbial storage metabolism can adjust to a wide range of environmental conditions. Such flexibility generates a selective advantage under fluctuating environmental conditions. It can also explain the different observations reported in PAO literature, including the capacity of “Ca. Accumulibacter phosphatis” to act like glycogen-accumulating organisms (GAOs). These observations stem from slightly...
Environmental Microbiology | SpotlightRisk Factors Associated with Carbapenemase-Producing Enterobacterales (CPE) Positivity in the Hospital Wastewater EnvironmentKlebsiella pneumoniae carbapenemase-producing organisms (KPCOs) are bacteria that are resistant to most antibiotics and thus are challenging to treat when they cause infections in patients. These organisms can be acquired by patients who are hospitalized for other reasons, complicating their hospital stay and even leading to death. Hospital wastewater sites, such as...
Environmental MicrobiologyGenome-Wide Identification of Host-Segregating Single-Nucleotide Polymorphisms for Source Attribution of Clinical Campylobacter coli IsolatesGenome-wide and source attribution studies based on Campylobacter species have shown their importance for the understanding of foodborne infections. Although the use of multilocus sequence typing based on 7 genes from C. jejuni is a powerful method to structure populations, when applied to C. coli...
Environmental MicrobiologyVariations among Viruses in Influent Water and Effluent Water at a Wastewater Plant over One Year as Assessed by Quantitative PCR and MetagenomicsBoth influent wastewater and treated wastewater at a wastewater treatment plant (WWTP) contain a high variety of human viral pathogens with seasonal variability when followed for 1 year. The peak of the amount of 11 different viruses in the inlet wastewater preceded the peak of the number of diagnosed patients by 2 to 4 weeks. The treatment of wastewater reduced viral concentrations by 3 to 6 log10. Despite the treatment of...
Environmental MicrobiologyNatural and Experimental Persistence of Highly Pathogenic H5 Influenza Viruses in Slurry of Domestic Ducks, with or without Lime TreatmentFrom November 2015 to July 2017, two successive episodes of H5 highly pathogenic avian influenza viruses (HP AIVs) infections occurred on poultry farms in France, mostly in domestic ducks raised for foie gras production in southwestern France. During the two epizootics, epidemiological investigations were carried out on infected farms and control and biosafety measures were implemented in association with surveillance in order to stop...
Food Microbiology
Food MicrobiologyLongitudinal Metatranscriptomic Analysis of a Meat Spoilage Microbiome Detects Abundant Continued Fermentation and Environmental Stress Responses during Shelf Life and BeyondIt is generally known which organisms are the typical SSO in foods, whereas the actively transcribed genes and pathways during microbial succession are poorly understood. This knowledge is important, since better approaches to food quality evaluation and shelf life determination are needed. Therefore, we conducted this study to find longitudinal markers that are connected to quality deterioration in a MAP beef product. This kind of RNA...
Food MicrobiologyTransformation of Microbial Negative Correlations into Positive Correlations by Saccharomyces cerevisiae Inoculation during Pomegranate Wine FermentationMicrobial interactions play an important role in flavor metabolism during traditional food and beverage fermentation. However, we understand little about how selected starters influence interactions among native microorganisms. In this study, we found that S. cerevisiae inoculation changed the interactions and metabolisms of native fungal communities during...
Genetics and Molecular Biology
Genetics and Molecular Biology | SpotlightBurkholderia thailandensis Methylated Hydroxyalkylquinolines: Biosynthesis and Antimicrobial Activity in CoculturesThe soil bacterium Burkholderia thailandensis produces 2-alkyl-4(1H)-quinolones that are mostly methylated 4-hydroxyalkenylquinolines, a family of relatively unstudied metabolites similar to molecules also synthesized by Pseudomonas aeruginosa. Several of the methylated 4-...
Genetics and Molecular BiologyExpression of an Extracellular Protein (SMU.63) Is Regulated by SprV in Streptococcus mutansWe previously identified a pleiotropic regulator, SprV, in Streptococcus mutans. This regulator appears to be highly conserved among streptococci. Here, we showed that SprV regulates the expression of a secreted protein encoded by SMU.63 in S. mutans. SMU.63 has been known to impact biofilm...
Genetics and Molecular BiologyMultiple Transporters and Glycoside Hydrolases Are Involved in Arabinoxylan-Derived Oligosaccharide Utilization in Bifidobacterium pseudocatenulatumBifidobacteria commonly reside in the human intestine and possess abundant genes involved in carbohydrate utilization. Arabinoxylan hydrolysates (AXH) are hydrolyzed products of arabinoxylan, one of the most abundant dietary fibers, and they include xylooligosaccharides and those decorated with arabinofuranosyl residues. The molecular mechanism by which B. pseudocatenulatum...
Genetics and Molecular BiologyThroat Microbial Community Structure and Functional Changes in Postsurgery Laryngeal Carcinoma PatientsLaryngeal squamous cell carcinoma greatly impacts patients’ lives, and noninvasive means of prognostic assessment are valuable in determining the effectiveness of laryngectomy. We set out to study the microbial structure changes in the throat before and after laryngectomy and found the gene functions of several throat bacteria to be associated with human cancer signaling pathways. Our findings may offer insights into the disease...
Genetics and Molecular BiologyNovel Modifications of Nonribosomal Peptides from Brevibacillus laterosporus MG64 and Investigation of Their Mode of ActionNRPs form a class of secondary metabolites with biocontrol and pharmaceutical potential. This work describes the identification of novel bogorol variants and succinylated bogorols (namely, succilins) and further investigates their biosynthetic pathway and mode of action. Adenylation domain-mediated lipoinitiation of bogorols represents a novel pathway by which NRPs incorporate fatty acid tails. This pathway provides the possibility to...
Genetics and Molecular BiologyCyclic-di-GMP Regulates the Quorum-Sensing System and Biocontrol Activity of Pseudomonas fluorescens 2P24 through the RsmA and RsmE ProteinsIn various bacteria, the bacterial second messenger c-di-GMP influences a wide range of cellular processes. However, the function of c-di-GMP on biocontrol traits in the plant-beneficial rhizobacteria remains largely unclear. The present work shows that the QS system and polyketide antibiotic 2,4-DAPG production are regulated by c-di-GMP through RsmA and RsmE proteins in P....
Genetics and Molecular BiologyPhenotypic and Transcriptomic Analyses of Seven Clinical Stenotrophomonas maltophilia Isolates Identify a Small Set of Shared and Commonly Regulated Genes Involved in the Biofilm LifestyleMicroorganisms living in a biofilm are much more tolerant to antibiotics and antimicrobial substances than planktonic cells are. Thus, the treatment of infections caused by microorganisms living in biofilms is extremely difficult. Nosocomial infections (among others) caused by S. maltophilia, particularly lung infection among CF patients, have increased in prevalence...
Geomicrobiology
GeomicrobiologyMixotrophic Iron-Oxidizing Thiomonas Isolates from an Acid Mine Drainage-Affected CreekAs AMD moves through the environment, it impacts aquatic ecosystems, but at the same time, these ecosystems can naturally attenuate contaminated waters via acid neutralization and catalyzing metal precipitation. This is the case in the former Ronneburg uranium-mining district, where AMD impacts creek sediments. We isolated and characterized two iron-oxidizing Thiomonas species that are mildly acidophilic to neutrophilic and...
Invertebrate Microbiology
Invertebrate MicrobiologyHeliconius Butterflies Host Characteristic and Phylogenetically Structured Adult-Stage MicrobiomesMany insects host microbiomes with important ecological functions. However, the prevalence of this phenomenon is unclear because in many insect taxa, microbiomes have been studied in only part of the life cycle, if at all. A prominent example is butterflies and moths, in which the composition and functional role of adult-stage microbiomes are largely unknown. We comprehensively characterized microbiomes in adult passion-vine butterflies...
Physiology
PhysiologySalt Stress Response of Sulfolobus acidocaldarius Involves Complex Trehalose Metabolism Utilizing a Novel Trehalose-6-Phosphate Synthase (TPS)/Trehalose-6-Phosphate Phosphatase (TPP) PathwayThe metabolism and function of trehalose as a compatible solute in Archaea was not well understood. This combined genetic and enzymatic approach at the interface of microbiology, physiology, and microbial ecology gives important insights into survival under stress, adaptation to extreme environments, and the role of compatible solutes in Archaea. Here, we unraveled the complexity of trehalose metabolism, and we present...
Physiology | SpotlightEcophysiological Study of Paraburkholderia sp. Strain 1N under Soil Solution Conditions: Dynamic Substrate Preferences and Characterization of Carbon Use EfficiencyExometabolomic footprinting methods have the capability to provide time-resolved observations of the uptake and release of hundreds of compounds during microbial growth. Of particular interest is microbial phenotyping under environmentally relevant soil conditions, consisting of relatively low concentrations and modeling pulse input events. Here, we show that growth of a bacterial soil isolate, Paraburkholderia sp. 1N, on a...
Public and Environmental Health Microbiology
Public and Environmental Health Microbiology | SpotlightSelection for Resistance to a Glyphosate-Containing Herbicide in Salmonella enterica Does Not Result in a Sustained Activation of the Tolerance Response or Increased Cross-Tolerance and Cross-Resistance to Clinically Important AntibioticsGlyphosate-based herbicides (GBH) are among the world’s most popular, with traces commonly found in food, feed, and the environment. Such high ubiquity means that the herbicide may come into contact with various microorganisms, on which it acts as an antimicrobial, and it may select for resistance and cross-resistance to clinically important antibiotics. It is therefore important to estimate whether the widespread use of pesticides may...
Public and Environmental Health MicrobiologyCarriage of Extended-Spectrum-Beta-Lactamase- and AmpC Beta-Lactamase-Producing Escherichia coli Strains from Humans and Pets in the Same HouseholdsEnterobacteriaceae that produce extended-spectrum beta-lactamases (ESBLs) and AmpC beta-lactamases (ACBLs) are important pathogens and can cause community-acquired illnesses, such as urinary tract infections (UTIs). Fecal carriage of these resistant bacteria by companion animals may pose a risk for transmission to humans. Our work evaluated the sharing of ESBL- and ACBL-producing...
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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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