A5058185953- Entomopathogenic Microorganisms in Pest Control
- Nematode management and characterization studies
- Insect symbiosis and bacterial influences
- Insect and Pesticide Research
- Insect Resistance and Genetics
- Bacterial Genetics and Biotechnology
- RNA and protein synthesis mechanisms
- Insect and Arachnid Ecology and Behavior
- Bacteriophages and microbial interactions
- Escherichia coli research studies
- Lipid Membrane Structure and Behavior
- Evolution and Genetic Dynamics
- Plant Reproductive Biology
- Transgenic Plants and Applications
- Vibrio bacteria research studies
- Insect-Plant Interactions and Control
- Legume Nitrogen Fixing Symbiosis
- Salmonella and Campylobacter epidemiology
- Sphingolipid Metabolism and Signaling
- Protein Kinase Regulation and GTPase Signaling
- Enzyme Production and Characterization
- Polyamine Metabolism and Applications
- Antimicrobial Peptides and Activities
- Vitamin K Research Studies
- Protein Hydrolysis and Bioactive Peptides
University of Wisconsin–Milwaukee
2013-2025
Taif University
2023
Milwaukee School of Engineering
2012
Saarland University
2006
The Ohio State University
2006
Eötvös Loránd University
2006
University of Wisconsin–Madison
1991-2004
Johnson University
1987-1993
Rutgers, The State University of New Jersey
1987-1991
State University of New York
1990
The Tar chemoreceptor of Escherichia coli is a membrane-bound sensory protein that facilitates bacterial chemotaxis in response to aspartate. EnvZ molecule has membrane topology similar and putative osmosensor required for osmoregulation the genes major outer porin proteins, OmpF OmpC. cytoplasmic signaling domain was replaced with carboxyl portion EnvZ, resulting chimeric receptor activated transcription ompC gene activation by absolutely dependent on OmpR, transcriptional activator ompF .
Members of the genus Xenorhabdus are entomopathogenic bacteria that associate with nematodes. The nematode-bacteria pair infects and kills insects, both partners contributing to insect pathogenesis providing nutrition nematode from available insect-derived nutrients. provides protection predators, access nutrients, a mechanism dispersal. bacterial Photorhabdus also nematodes kill genera provide similar services their different hosts through unique physiological metabolic mechanisms. We...
OmpR and EnvZ, the protein products of ompB locus, are regulatory components required for osmoexpression outer membrane porin proteins, OmpF OmpC, in Escherichia coli. EnvZ is considered to be an osmosensor which transmits signals across OmpR, a transcriptional activator ompF ompC. We inserted envZ gene into high expression vector, pIN-III. Following cellular fractionation, was found localized inner membrane. Sequence analysis revealed that signal peptide-like N-terminal sequence not removed...
The role of chromosomally derived micF RNA as a repressor outer membrane protein OmpF Escherichia coli was examined for various growth conditions. Levels determined by Northern analyses are found to increase in response cell at high temperature, osmolarity or the presence ethanol. After switch higher levels ompF mRNA and newly synthesized decrease with time E. strain, MC4100 but these decreases not observed isogenic deletion SM3001. In addition, while substantially reduced both strains...
Two-component signal transduction systems, consisting of histidine kinase (HK) sensors and DNA-binding response regulators, allow bacteria archaea to respond diverse environmental stimuli. HKs possess a conserved domain (H-box region) which contains the site phosphorylation an ATP-binding domain. In this study, genomic approach was taken analyse HK family in archaea. Based on phylogenetic analysis, differences sequence organization H-box domains, predicted secondary structure region, five...
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTStructural and functional properties of a phospholipase A2 purified from an inflammatory exudateSteven Forst, Jerrold Weiss, Peter Elsbach, John M. Maraganore, Ilene Reardon, Robert L. HeinriksonCite this: Biochemistry 1986, 25, 26, 8381–8385Publication Date (Print):December 1, 1986Publication History Published online1 May 2002Published inissue 1 December...
ABSTRACT We present results from epifluorescence, differential interference contrast, and transmission electron microscopy showing that Xenorhabdus nematophila colonizes a receptacle in the anterior intestine of infective juvenile (IJ) stage Steinernema carpocapsae . This region is connected to esophagus at esophagointestinal junction. The process by which X. leaves this bacterial had not been analyzed previously. In study we monitored movement green fluorescent protein-labeled bacteria...
ABSTRACT Microbial symbionts provide benefits that contribute to the ecology and fitness of host plants animals. Therefore, evolutionary success animals fundamentally depends on long-term maintenance beneficial associations. Most work investigating coevolution symbiotic has focused species-level associations, studies are lacking assess impact bacterial strain diversity associations within a coevolutionary framework. Here, we demonstrate in mutualism varies depending identity, this is...
Summary In Escherichia coli the OmpR and EnvZ proteins regulate expression of outer membrane porin OmpC OmpF. belong to a family sensor/effector protein pairs that control adaptation variety environmental conditions. acts as sensor phosphorylates OmpR, which in turn regulates gene expression. The level phosphorylated appears be determining factor for ompC ompF regulation. Phosphorylation is considered occur at one or more aspartic acid residues (Asp‐11, Asp‐12 and/or Asp‐55) are highly...
Xenocoumacin 1 (Xcn1) and xenocoumacin 2 (Xcn2) are the major antimicrobial compounds produced by Xenorhabdus nematophila. To study role of Xcn1 Xcn2 in life cycle X. nematophila 14 gene cluster (xcnA-N) required for their synthesis was identified. Overlap RT-PCR analysis identified six xcn transcripts. Individual inactivation non-ribosomal peptide synthetase genes, xcnA xcnK, polyketide xcnF, xcnH xcnL, eliminated production. levels expression xcnA-L were increased an ompR strain while...
Abstract The decades-long gap in antibiotic discovery has led to a significant health crisis due antimicrobial resistance (AMR). bacterial genus Xenorhabdus , which forms symbiotic relationships with the soil nematode Steinernema are known secrete variety of compounds potential effectiveness against AMR. These primarily bio-synthesized by non-ribosomal peptide synthetases (NRPS) and polyketide synthetase (PKS) genes. In this study, we report that X. szentirmaii produces high levels activity...
The decades-long gap in antibiotic discovery has led to a significant health crisis due antimicrobial resistance (AMR). bacterial genus Xenorhabdus , which forms symbiotic relationships with the soil nematode Steinernema are known secrete variety of compounds potential effectiveness against AMR. These primarily bio-synthesized by non-ribosomal peptide synthetases (NRPS) and polyketide synthase (PKS) genes. In this study, we report that X. szentirmaii produces high levels activity during...
Xenorhabdus nematophila is an emerging model for both mutualism and pathogenicity in different invertebrate hosts. Here we conduct a mutant study of the EnvZ-OmpR two-component system flagella sigma factor, FliA (sigma28). Both ompR envZ strains displayed precocious swarming behaviour, elevated flhD fliA mRNA levels early production lipase, protease, haemolysin antibiotic activity. Inactivation eliminated exoenzyme which was restored by complementation with fliAZ operon. flhA, gene encoding...
Xenofuranones A (1) and B (2) have been isolated from cultures of the insect-pathogenic bacterium Xenorhabdus szentirmaii, their structures were elucidated by NMR mass spectroscopy. Both compounds show similarities to fungal furanones, biosynthesis was studied using a reversed approach feeding putative 12C precursors an overall 13C background in small-scale experiments followed gas chromatographic analysis coupled spectrometry.
The role of antibiotics produced by bacterial symbionts entomopathogenic nematodes is to suppress growth microbes in the soil environment. These are active against Gram-positive and Gram-negative bacteria, were tested mastitis isolates from dairy cows.Two bioassays adapted for Xenorhabdus antibiotics; an overlay method on agar plates, serially diluted, cell-free, cultures. antimicrobial activities liquid cultures 13 strains five species further evaluated. Antimicrobial type X. nematophila,...
ABSTRACT Xenorhabdus nematophila , the mutualistic bacterium of nematode Steinernema carpocapsae produces R-type bacteriocin called xenorhabdicin, which is thought to confer a competitive advantage for growth in insect host. We have identified P2-like tail synthesis gene cluster ( xnp1 ) that required xenorhabdicin production. The genes were expressed constitutively during and induced by mitomycin C. Deletion either sheath xnpS1 or fiber xnpH1 eliminated Production bacteriocins host organism...
ABSTRACT Xenorhabdus nematophilus is a symbiotic bacterium that inhabits the intestine of entomopathogenic nematodes. The bacterium-nematode pair pathogenic for larval-stage insects. phase I cell type form normally associated with nematode. A variant type, referred to as II, can spontaneously under stationary-phase conditions. Phase II cells do not elaborate products type. To better define variation in X. , several strains (19061, AN6, F1, N2-4) this were analyzed new phenotypic traits. An...
The repressor RNA, micF is regulated by temperature, osmolarity, and other stress conditions during growth of Escherichia coli. Northern (RNA) blot analyses showed that levels RNA differ widely in various ompB mutant strains when cells are grown at 24 degrees C LB broth. For example, relative to the parental strain MC4100, ompR101 (which contains no functional OmpR) had about a 10-fold reduction whereas envZ11 5-fold increase. At 37 C, however, mutants differed less than two-fold compared...