| polyclonal antisera to distinguish strains and form variants of photorhabdus (xenorhabdus) luminescens. | in this study antisera against photorhabdus luminescens strains were prepared for the first time. p. luminescens is a bacterial symbiont of entomopathogenic nematodes belonging to the genus heterorhabditis. to characterize p. luminescens strains and form variants, we produced polyclonal antisera against p. luminescens pe (obtained from nematode strain nlh-e87.3) and against the primary and secondary forms of p. luminescens psh (obtained from nematode strain dh-sh1). in double-diffusion tests all ... | 1995 | 16534911 |
| influence of osmolarity on phase shift in photorhabdus luminescens. | the influence of osmolarity and other environmental factors like low oxygen levels, light, extreme ph values, and temperatures on phase variation of photorhabdus luminescens, the symbiotic bacterium of entomopathogenic nematodes of the genus heterorhabditis, was investigated. only subculturing in low-osmolarity medium triggered a phase shift to secondary phase reliably. | 1995 | 16535154 |
| composition and biophysical properties of lipids in xenorhabdus nematophilus and photorhabdus luminescens, symbiotic bacteria associated with entomopathogenic nematodes. | primary and secondary forms of photorhabdus luminescens hm and xenorhabdus nematophilus n2-4 were grown at 18 and 28(deg)c for 24 to 96 h, and we made determinations of the fatty-acid compositions of total lipids and of the fluidity measured by 5-doxyl-stearic acid embedded in liposomes made from total lipids. the levels of the unsaturated fatty acids 16:1 and 18:1 (those with chain lengths of 16 or 18 and one double bond) generally were higher in primary-phase variants of p. luminescens grown a ... | 1997 | 16535651 |
| proteome analysis of the phenotypic variation process in photorhabdus luminescens. | photorhabdus luminescens is an insect pathogen associated with specific soil nematodes. the bacterium has a complex life cycle with a symbiotic stage in which bacteria colonize the intestinal tract of the nematodes, and a pathogenic stage against susceptible larval-stage insect. symbiosis-"deficient" phenotypic variants (known as secondary forms) arise during prolonged incubation. correspondence analysis of the in silico proteome translated from the genome sequence of strain tt01 identified two ... | 2006 | 16548063 |
| rnai suppression of recognition protein mediated immune responses in the tobacco hornworm manduca sexta causes increased susceptibility to the insect pathogen photorhabdus. | bacterial pathogens either hide from or overcome the immune response of their hosts. here we show that two different species of insect pathogenic bacteria, photorhabdus luminescens tt01 and photorhabdus asymbiotica atcc43949, were both recognized by the immune system of their host manduca sexta, as indicated by a rapid increase in the levels of mrnas encoding three different inducible microbial recognition proteins, hemolin, immulectin-2 and peptidoglycan recognition protein. rna interference (r ... | 2006 | 16620974 |
| photorhabdus luminescens toxin-induced permeability change in manduca sexta and tenebrio molitor midgut brush border membrane and in unilamellar phospholipid vesicle. | photorhabdus luminescens, a gram-negative bacterium, secretes a protein toxin (pl toxin) that is toxic to insects. in this study, the effects of the pl toxin on large receptor-free unilamellar phospholipid vesicles (luvs) of manduca sexta and on brush border membrane vesicles (bbmvs) of m. sexta and tenebrio molitor were examined. cry1ac served as a positive control in our experiments due to its known channel-forming activity on m. sexta. voltage clamping assays with dissected midguts of m. sext ... | 2006 | 16623743 |
| a novel antimicrobial epoxide isolated from larval galleria mellonella infected by the nematode symbiont, photorhabdus luminescens (enterobacteriaceae). | a novel antimicrobial epoxide, 2-isopropyl-5-(3-phenyl-oxiranyl)-benzene-1,3-diol (1), was identified from larval galleria mellonella infected by a symbiotically associated bacterium-nematode complex (photorhabdus luminescens c9-heterorhabditis megidis 90). its structure was determined with spectroscopic analysis and confirmed by chemical synthesis starting from a known antibiotic, 2-isopropyl-5-(2-phenylethenyl)-benzene-1,3-diol (2). epoxide 1 was active against bacillus subtilis, escherichia c ... | 2006 | 16644226 |
| search for fucose binding domains in recently sequenced hypothetical proteins using molecular modeling techniques and structural analysis. | the crystal structure of a fucose-binding lectin from the bacteria pseudomonas aeruginosa in complex with alpha-l-fucose has been recently determined. it is a tetramer; each monomer displays a nine-stranded, antiparallel, beta-sandwiched arrangement and contains two calcium ions that mediate the binding of fucose in a recognition mode unique among protein-carbohydrate interactions. in search of this type of unique interactions in other newly discovered protein sequences, we have used molecular m ... | 2006 | 16691508 |
| outer membrane protein genes and their small non-coding rna regulator genes in photorhabdus luminescens. | three major outer membrane protein genes of escherichia coli, ompf, ompc, and ompa respond to stress factors. transcripts from these genes are regulated by the small non-coding rnas micf, micc, and mica, respectively. here we examine photorhabdus luminescens, an organism that has a different habitat from e. coli for outer membrane protein genes and their regulatory rna genes. | 2006 | 16716220 |
| prior infection of manduca sexta with non-pathogenic escherichia coli elicits immunity to pathogenic photorhabdus luminescens: roles of immune-related proteins shown by rna interference. | prior infection of manduca sexta caterpillars with the non-pathogenic bacterium escherichia coli elicits effective immunity against subsequent infection by the usually lethal and highly virulent insect pathogen photorhabdus luminescens tt01. induction of this protective effect is associated with up-regulation of both microbial pattern recognition protein genes (hemolin, immulectin-2 and peptidoglycan recognition protein) and anti-bacterial effector genes (attacin, cecropin, lebocin, lysozyme and ... | 2006 | 16731347 |
| yersiniabactin production by pseudomonas syringae and escherichia coli, and description of a second yersiniabactin locus evolutionary group. | the siderophore and virulence factor yersiniabactin is produced by pseudomonas syringae. yersiniabactin was originally detected by high-pressure liquid chromatography (hplc); commonly used pcr tests proved ineffective. yersiniabactin production in p. syringae correlated with the possession of irp1 located in a predicted yersiniabactin locus. three similarly divergent yersiniabactin locus groups were determined: the yersinia pestis group, the p. syringae group, and the photorhabdus luminescens gr ... | 2006 | 16751485 |
| direct infection of spodoptera litura by photorhabdus luminescens encapsulated in alginate beads. | actively growing cultures of photorhabdus luminescens were encapsulated in sodium alginate beads and examined for their ability to infect insect hosts. these beads, containing approximately 2.5 x 10(7)photorhabdus cells per bead, when mixed with sterilized soil and exposed to spodoptera litura larvae resulted in 100% mortality in 48 h, while the use of alginate encapsulated heterorhabditis nematode resulted in 40% mortality after 72 h. the bacteria were reisolated from the dead insect thus provi ... | 2006 | 16828112 |
| development of bioluminescent edwardsiella ictaluri for noninvasive disease monitoring. | edwardsiella ictaluri is a facultative intracellular bacterium that causes enteric septicemia of catfish (esc). in this study, we aimed to develop bioluminescent e. ictaluri that can be monitored by noninvasive bioluminescence imaging (bli). to accomplish this, the luxcdabe operon of photorhabdus luminescens was cloned downstream of the lacz promoter in the broad host range plasmid pbbr1mcs4. edwardsiella ictaluri strain 93-146 transformed with the new plasmid, paklux1, was highly bioluminescent ... | 2006 | 16842347 |
| beta-galactosidase production by streptococcus thermophilus is higher in the small intestine than in the caecum of human-microbiota-associated mice after lactose supplementation. | transit kinetics and survival rates of a bacterial species from yoghurt (i.e. streptococcus thermophilus strain fbi3) were examined in different digestive compartments of gnotoxenic and human-microbiota-associated mice. the production of the lactose-hydrolysing enzyme (i.e. beta-galactosidase) was also investigated within the digestive tract, using a chromosomal reporter system based on luciferase genes from photorhabdus luminescens under the control of the plac promoter. in both mice models, s. ... | 2006 | 16870007 |
| stability of entomopathogenic bacteria, xenorhabdus nematophila and photorhabdus luminescens, during in vitro culture. | the entomopathogenic nematode-bacteria complexes heterorhabditis bacteriophora/photorhabdus luminescens and steinernema carpocapsae/xenorhabdus nematophila are mass produced for use as biological insecticides. stability of the bacterial partner in culture is essential for maintaining traits important for both biological control and production. two geographically distinct strains of each bacterial species were isolated from their nematode partners and serially subcultured on in vitro media to ass ... | 2007 | 16941119 |
| spite. | | 2006 | 16950082 |
| ytxr, a conserved lysr-like regulator that induces expression of genes encoding a putative adp-ribosyltransferase toxin homologue in yersinia enterocolitica. | yersinia enterocolitica causes human gastroenteritis, and many isolates have been classified as either "american" or "non-american" strains based on their geographic prevalence and virulence properties. in this study we describe identification of a transcriptional regulator that controls expression of the y. enterocolitica ytxab genes. the ytxab genes have the potential to encode an adp-ribosylating toxin with similarity to pertussis toxin. however, a ytxab null mutation did not affect virulence ... | 2006 | 16997967 |
| comparison of bulb syringe and pulsed lavage irrigation with use of a bioluminescent musculoskeletal wound model. | despite the fact that wound irrigation is a common surgical procedure, there are many variables, including delivery device, irrigant type, and fluid volume, that have yet to be optimized. the purpose of this study was to compare, with use of transgenic bioluminescent bacteria and standard quantitative microbiological methods, the efficacy of pulsed lavage and bulb syringe irrigation in reducing wound bacterial counts. | 2006 | 17015593 |
| pleiotropic role of quorum-sensing autoinducer 2 in photorhabdus luminescens. | bacterial virulence is an integrative process that may involve quorum sensing. in this work, we compared by global expression profiling the wild-type entomopathogenic photorhabdus luminescens subsp. laumondii tt01 to a luxs-deficient mutant unable to synthesize the type 2 quorum-sensing inducer ai-2. ai-2 was shown to regulate more than 300 targets involved in most compartments and metabolic pathways of the cell. ai-2 is located high in the hierarchy, as it controls the expression of several tra ... | 2006 | 17021191 |
| [host factors in the regulation of the vibrio fischeri lux operon in escherichia coli cells]. | it has been shown that the chaperonin groel, together with groes co-chaperonin and lon atp-dependent protease are involved in the regulation of expression of the vibrio fischeri lux operon in escherichia coli cells. the cells of e. coli groe (pf1)- bearing a plasmid with the complete v. fischeri lux regulon were weakly luminescent. the cells of e. coli lona (pf1) displayed intense bioluminescence. the same effects also occurred in mutant e. coli strains bearing a hybrid plasmid pvfr1, where the ... | 2006 | 17025179 |
| from insects to human hosts: identification of major genomic differences between entomopathogenic strains of photorhabdus and the emerging human pathogen photorhabdus asymbiotica. | pathogenic bacteria of the genus photorhabdus are naturally found in symbiotic association with soil entomopathogenic nematodes, and are of increasing economic interest in view of their potential for the development of novel biopesticides. this bipartite natural system is currently used for the biological control of crop pests in several countries. however, an increasing number of photorhabdus strains have recently been isolated from human clinical specimens in both the united states and austral ... | 2006 | 17029962 |
| the broadly insecticidal photorhabdus luminescens toxin complex a (tca): activity against the colorado potato beetle, leptinotarsa decemlineata, and sweet potato whitefly, bemisia tabaci. | toxin complex a (tca), a high molecular weight insecticidal protein complex produced by the entomopathogenic bacterium photorhabdus luminescens, has been found to be orally toxic to both the colorado potato beetle, leptinotarsa decemlineata, and the sweet potato whitefly, bemisia tabaci biotype b. the 48 hour lc50 for tca against neonate l. decemlineata was found to be 2.7 ppm, and the growth of 2nd instar l. decemlineata exposed to tca for 72 hours was almost entirely inhibited at concentration ... | 2005 | 17119614 |
| lateral transfer of the lux gene cluster. | the lux operon is an uncommon gene cluster. to find the pathway through which the operon has been transferred, we sequenced the operon and both flanking regions in four typical luminous species. in vibrio cholerae ncimb 41, a five-gene cluster, most genes of which were highly similar to orthologues present in gram-positive bacteria, along with the lux operon, is inserted between vc1560 and vc1563, on chromosome 1. because this entire five-gene cluster is present in photorhabdus luminescens tt01, ... | 2007 | 17169972 |
| dual role of the mgtc virulence factor in host and non-host environments. | mgtc is required for intramacrophage replication of intracellular pathogens and growth in low mg(2+) medium. a link between these two phenotypes has been proposed due to putative mg(2+) deprivation inside phagosome. mgtc is part of a family of proteins that share a conserved n-terminal transmembrane domain and a variable c-terminal domain. a combination of predictive and experimental approaches indicates that the salmonella mgtc c-terminal domain is cytoplasmic, adopts a fold also found in metal ... | 2007 | 17176255 |
| nematode symbiont for photorhabdus asymbiotica. | photorhabdus asymbiotica is an emerging bacterial pathogen that causes locally invasive soft tissue and disseminated bacteremic infections in the united states and australia. although the source of infection was previously unknown, we report that the bacterium is found in a symbiotic association with an insect-pathogenic soil nematode of the genus heterorhabditis. | 2006 | 17176572 |
| insecticidal toxins from photorhabdus bacteria and their potential use in agriculture. | most of the insecticidal toxins used in agriculture come from a single bacterium bacillus thuringiensis or 'bt'. here we review our work on the array of toxins produced by photorhabdus and xenorhabdus bacteria that are symbiotic with entomopathogenic nematodes, and discuss their potential for use in agriculture as alternatives to bt. despite the fact that both photorhabdus and xenorhabdus are introduced directly into the insect blood stream by their nematode vectors, they produce a range of toxi ... | 2007 | 17207509 |
| broad host range fluorescence and bioluminescence expression vectors for gram-negative bacteria. | tagging of bacteria with living colors and living light allows increasingly valuable new imaging and detection technologies to be accessible to researchers. in this study, we aimed to create stable broad host range expression vectors for tagging gram-negative bacteria with fluorescence and bioluminescence. to accomplish this, a mutated form of promoterless green fluorescent protein (gfp) gene, gfpmut3a, from aequorea victoria and promoterless bacterial luciferase genes, luxcdabe, from photorhabd ... | 2007 | 17207855 |
| the effect of photorhabdus luminescens (enterobacteriaceae) on the survival, development, reproduction and behaviour of caenorhabditis elegans (nematoda: rhabditidae). | the free-living soil nematode caenorhabditis elegans interacts with diverse microorganisms in its natural habitat. these microorganisms may serve as a food source or represent a harmful threat. as such, they constitute one of the most important ecological factors of the worm's natural environment. in this study, we examined the interaction between two natural isolates of c. elegans and three natural isolates of the entomopathogenic bacterium photorhabdus luminescens. two of the tested p. lumines ... | 2007 | 17227408 |
| the xaxab genes encoding a new apoptotic toxin from the insect pathogen xenorhabdus nematophila are present in plant and human pathogens. | xenorhabdus nematophila, a member of the enterobacteriaceae, kills many species of insects by strongly depressing the immune system and colonizing the entire body. a peptide cytotoxin has been purified from x. nematophila broth growth, and the cytolytic effect on insect immunocytes and hemolytic effect on mammalian red blood cells of this toxin have been described (ribeiro, c., vignes, m., and brehélin, m. (2003) j. biol. chem. 278, 3030-3039). we show here that this toxin, xenorhabdus alpha-xen ... | 2007 | 17229739 |
| an antibiotic produced by an insect-pathogenic bacterium suppresses host defenses through phenoloxidase inhibition. | photorhabdus is a virulent pathogen that kills its insect host by overcoming immune responses. the bacterium also secretes a range of antibiotics to suppress the growth of other invading microorganisms. here we show that photorhabdus produces a small-molecule antibiotic (e)-1,3-dihydroxy-2-(isopropyl)-5-(2-phenylethenyl)benzene (st) that also acts as an inhibitor of phenoloxidase (po) in the insect host manduca sexta. the photorhabdus gene stla encodes an enzyme that produces cinnamic acid, a ke ... | 2007 | 17284598 |
| a synthetic luxcdabe gene cluster optimized for expression in high-gc bacteria. | the luxcdabe operon of the bioluminescent bacterium photorhabdus luminescens has proven to be a superb transcriptional reporter. it encodes a luciferase (luxa and luxb) and the enzymes that produce its substrate (luxc, luxd and luxe) so cells that express the cluster emit the 490-nm light spontaneously. the sequence of these genes is at-rich (>69%) and for this and other reasons, they are not expressed efficiently in high-gc bacteria like streptomyces coelicolor. we therefore constructed a synth ... | 2007 | 17337439 |
| cleavage site analysis of a serralysin-like protease, prta, from an insect pathogen photorhabdus luminescens and development of a highly sensitive and specific substrate. | the aim of this study was the development of a sensitive and specific substrate for protease a (prta), a serralysin-like metzincin from the entomopathogenic microorganism, photorhabdus. first, cleavage of three biological peptides, the a and b chains of insulin and beta-lipotropin, and of 15 synthetic peptides, was investigated. in the biological peptides, a preference for the hydrophobic residues ala, leu and val was observed at three substrate positions, p2, p1' and p2'. at these positions in ... | 2007 | 17355285 |
| on-line determination of serum bactericidal activity using recombinant luminescent bacteria. | intensity of luminescence quenching in recombinant strains of escherichia coli with cloned lux-operones by human blood serum is directly proportional to the degree of bactericidal effect assessed by nephelometric and bacteriological methods. this correlation was most characteristic of e. coli with luminescence genes from photobacterium leiognathi, which substantiates its use in the development of the kinetic bioluminescent method to determine of serum bactericidal activity. the possibility of us ... | 2006 | 17369948 |
| autoprocessing of the vibrio cholerae rtx toxin by the cysteine protease domain. | vibrio cholerae rtx is a large multifunctional bacterial toxin that causes actin crosslinking. due to its size, it was predicted to undergo proteolytic cleavage during translocation into host cells to deliver activity domains to the cytosol. in this study, we identified a domain within the rtx toxin that is conserved in large clostridial glucosylating toxins tcdb, tcda, tcna, and tcsl; putative toxins from v. vulnificus, yersinia sp., photorhabdus sp., and xenorhabdus sp.; and a filamentous/hema ... | 2007 | 17464284 |
| engineering central metabolic pathways for high-level flavonoid production in escherichia coli. | the identification of optimal genotypes that result in improved production of recombinant metabolites remains an engineering conundrum. in the present work, various strategies to reengineer central metabolism in escherichia coli were explored for robust synthesis of flavanones, the common precursors of plant flavonoid secondary metabolites. augmentation of the intracellular malonyl coenzyme a (malonyl-coa) pool through the coordinated overexpression of four acetyl-coa carboxylase (acc) subunits ... | 2007 | 17468269 |
| nematodes, bacteria, and flies: a tripartite model for nematode parasitism. | more than a quarter of the world's population is infected with nematode parasites, and more than a hundred species of nematodes are parasites of humans [1-3]. despite extensive morbidity and mortality caused by nematode parasites, the biological mechanisms of host-parasite interactions are poorly understood, largely because of the lack of genetically tractable model systems. we have demonstrated that the insect parasitic nematode heterorhabditis bacteriophora, its bacterial symbiont photorhabdus ... | 2007 | 17475494 |
| mutualism and pathogenesis in xenorhabdus and photorhabdus: two roads to the same destination. | photorhabdus and xenorhabdus bacteria colonize the intestines of the infective soil-dwelling stage of entomophagous nematodes, heterorhabditis and steinernema, respectively. these nematodes infect susceptible insect larvae and release the bacteria into the insect blood. the bacteria kill the insect larvae and convert the cadaver into a food source suitable for nematode growth and development. after several rounds of reproduction the nematodes are recolonized by the bacteria before emerging from ... | 2007 | 17493120 |
| identification and type iii-dependent secretion of the yersinia pestis insecticidal-like proteins. | plague, or the black death, is a zoonotic disease that is spread from mammal to mammal by fleas. this mode of transmission demands that the causative agent of this disease, yersinia pestis, is able to survive and multiply in both mammals and insects. in recent years the complete genome sequence of a number of y. pestis strains have been determined. this sequence information indicates that y. pestis contains a cluster of genes with homology to insecticidal toxin encoding genes of the insect patho ... | 2007 | 17542916 |
| identification of genes involved in the biosynthesis of the cytotoxic compound glidobactin from a soil bacterium. | glidobactins (syn. cepafungins) are a family of structurally related cytotoxic compounds that were isolated from the soil bacterial strain k481-b101 (atcc 53080; dsm 7029) originally assigned to polyangium brachysporum and, independently, from an undefined species related to burkholderia cepacia. glidobactins are acylated tripeptide derivatives that contain a 12-membered ring structure consisting of the two unique non-proteinogenic amino acids erythro-4-hydroxy-l-lysine and 4(s)-amino-2(e)-pente ... | 2007 | 17564599 |
| expression and insecticidal activity of yersinia pseudotuberculosis and photorhabdus luminescens toxin complex proteins. | photorhabdus luminescens toxin complex (tc) has been characterized as a potent three-component insecticidal protein complex. homologues of genes encoding p. luminescens tc components have been identified in several other enterobacteria and in gram-positive bacteria, showing these genes are widespread in bacteria. in particular, tc gene homologues have been identified in yersinia enterocolitica, yersinia pseudotuberculosis and yersinia pestis and may have a role in y. pestis evolution. y. enteroc ... | 2007 | 17573906 |
| applications of bioluminescence imaging to the study of infectious diseases. | bioluminescence imaging (bli) has emerged as a powerful new method to analyse infectious diseases in animal models. bli offers real-time monitoring of spatial and temporal progression of infection in the same animal, as opposed to euthanizing a cohort of animals and quantifying colony or plaque forming units at multiple time points. pathogens or mice are engineered to express genetically encoded luciferase enzymes from bacteria, insects, or the sea pansy. the seminal study showing the feasibilit ... | 2007 | 17587328 |
| acute oral toxicity of yersinia pseudotuberculosis to fleas: implications for the evolution of vector-borne transmission of plague. | yersinia pestis diverged from yersinia pseudotuberculosis</= 20 000 years ago, during which time it evolved to be transmitted by fleas. in comparing the ability of these closely related species to infect the rat flea xenopsylla cheopis, we found that y. pseudotuberculosis, unlike y. pestis, is orally toxic to fleas. fleas showed signs of acute toxicity, including diarrhoea, immediately after feeding on blood containing y. pseudotuberculosis in response to protein toxin(s) produced by the bacteri ... | 2007 | 17587333 |
| a high-throughput, homogeneous, bioluminescent assay for pseudomonas aeruginosa gyrase inhibitors and other dna-damaging agents. | a homogeneous, sensitive, cellular bioluminescent high-throughput screen was developed for inhibitors of gyrase and other dna-damaging agents in pseudomonas aeruginosa. the screen is based on a photorhabdus luminescens luciferase operon transcriptional fusion to a promoter that responds to dna damage caused by reduced gyrase levels and fluoroquinolone inhibition. this reporter strain is sensitive to levels of ciprofloxacin as low as one-fourth minimum inhibitory concentration (mic) with z' score ... | 2007 | 17644773 |
| bioluminescent salmonella reverse mutation assay: a screen for detecting mutagenicity with high throughput attributes. | here, we describe the development and evaluation of a novel bioluminescent high-throughput salmonella reverse mutation assay applicable to the screening of large numbers of small molecules. the bioluminescent salmonella assay utilizes genetically engineered standard salmonella tester strains ta98 and ta100 expressing the lux(cdabe) operon from xenorhabdus luminescence. in principle, the assay employs bioluminescence as a sensor of changes in bacterial metabolism associated with starvation or ene ... | 2007 | 17656636 |
| critical role of glu175 on stability and folding of bacterial luciferase: stopped-flow fluorescence study. | bacterial luciferase is a heterodimeric enzyme, which catalyzes the light emission reaction, utilizing reduced fmn (fmnh2), a long chain aliphatic aldehyde and o(2), to produce green-blue light. this enzyme can be readily classed as slow or fast decay based on their rate of luminescence decay in a single turnover. mutation of glu175 in alpha subunit to gly converted slow decay xenorhabdus luminescence luciferase to fast decay one. the following studies revealed that changing the luciferase flexi ... | 2007 | 17669259 |
| a common fold mediates vertebrate defense and bacterial attack. | proteins containing membrane attack complex/perforin (macpf) domains play important roles in vertebrate immunity, embryonic development, and neural-cell migration. in vertebrates, the ninth component of complement and perforin form oligomeric pores that lyse bacteria and kill virus-infected cells, respectively. however, the mechanism of macpf function is unknown. we determined the crystal structure of a bacterial macpf protein, plu-macpf from photorhabdus luminescens, to 2.0 angstrom resolution. ... | 2007 | 17717151 |
| a type ii polyketide synthase is responsible for anthraquinone biosynthesis in photorhabdus luminescens. | type ii polyketide synthases are involved in the biosynthesis of numerous clinically relevant secondary metabolites with potent antibiotic or anticancer activity. until recently the only known producers of type ii pkss were members of the gram-positive actimomycetes, well-known producers of secondary metabolites in general. here we present the second example of a type ii pks from gram-negative bacteria. we have identified the biosynthesis gene cluster responsible for the production of anthraquin ... | 2007 | 17722122 |
| postembryonic rnai in heterorhabditis bacteriophora: a nematode insect parasite and host for insect pathogenic symbionts. | heterorhabditis bacteriophora is applied throughout the world for the biological control of insects and is an animal model to study interspecies interactions, e.g. mutualism, parasitism and vector-borne disease. h. bacteriophora nematodes are mutually associated with the insect pathogen, photorhabdus luminescens. the developmentally arrested infective juvenile (ij) stage nematode (vector) specifically transmits photorhabdus luminescens bacteria (pathogen) in its gut mucosa to the haemocoel of in ... | 2007 | 17803822 |
| the mcf1 toxin induces apoptosis via the mitochondrial pathway and apoptosis is attenuated by mutation of the bh3-like domain. | photorhabdus are gram-negative, nematode-vectored bacteria that produce toxins to kill their insect hosts. the expression of one of these, makes caterpillars floppy 1 (mcf1), is sufficient to allow escherichia coli to survive within, and kill, caterpillars which are otherwise able to clear e. coli infection. mcf1 treated caterpillars show rapid loss of body turgor (the 'floppy' phenotype) and death is associated with massive apoptosis of both the midgut epithelium and insect phagocytes. mammalia ... | 2007 | 17848168 |
| action of 1,1-dimethylhydrazine on bacterial cells is determined by hydrogen peroxide. | seven different recombinant bioluminescent strains of escherichia coli containing, respectively, the promoters katg and soxs (responsive to oxidative damage), reca (dna damage), faba (membrane damage), grpe, and rpoe (protein damage) and lac (constitutive expression) fused to the bacterial operon from photorhabdus luminescens, were used to describe the mechanism of toxicity of 1,1-dimethylhydrazine (1,1-dmh) on bacteria, as well as to determine whether bacteria can sensitively detect the presenc ... | 2007 | 17869570 |
| a metalloprotease secreted by the insect pathogen photorhabdus luminescens induces melanization. | photorhabdus luminescens is a gram-negative insect pathogen that enters the hemocoel of infected hosts and produces a number of secreted proteins that promote colonization and subsequent death of the insect. in initial studies to determine the exact role of individual secreted proteins in insect pathogenesis, concentrated culture supernatants from various p. luminescens strains were injected into the tobacco hornworm manduca sexta. culture supernatants from p. luminescens tt01, the genome-sequen ... | 2007 | 17933944 |
| a nematode symbiont sheds light on invertebrate immunity. | photorhabdus bacteria live in a 'symbiosis of pathogens' with nematodes that invade and kill insects. recent work has begun to use the power of the model insect drosophila to dissect the molecular basis of the invertebrate immune response to the combined insult of the worms and their symbiotic bacterial pathogens. by using rna interference, it is now also possible to dissect this complex tripartite interaction in a range of both model and non-model hosts. | 2007 | 17964855 |
| the insect toxin complex of yersinia. | many members of the yersinia genus encode homologues of insect toxins first observed in bacteria that are insect pathogens such as photorhabdus, xenorhabdus and serratia entomophila. these bacteria secrete high molecular weight insecticidal toxins comprised of multiple protein subunits, termed the toxin complexes or tc's. in photorhabdus three distinct tc subunits are required for full oral toxicity in insects, that include the [a], [b] and [c] types, although the exact stochiometry remains uncl ... | 2007 | 17966421 |
| high-throughput quantitative luminescence assay of the growth in planta of pseudomonas syringae chromosomally tagged with photorhabdus luminescens luxcdabe. | bioluminescent strains of the arabidopsis thaliana pathogens pseudomonas syringae pathovar (pv.) tomato and pv. maculicola were made by insertion of the luxcdabe operon from photorhabdus luminescens into the p. syringae chromosome under the control of a constitutive promoter. stable integration of luxcdabe did not affect bacterial fitness, growth in planta or disease outcome. luminescence accurately and reliably reported bacterial growth in infected arabidopsis leaves both with a fixed inoculum ... | 2008 | 17971037 |
| developmental modulation of immunity: changes within the feeding period of the fifth larval stage in the defence reactions of manduca sexta to infection by photorhabdus. | in insect pathogen interactions, host developmental stage is among several factors that influence the induction of immune responses. here, we show that the effectiveness of immune reactions to a pathogen can vary markedly within a single larval stage. pre-wandering fifth-stage (day 5) larvae of the model lepidopteran insect manduca sexta succumb faster to infection by the insect pathogenic bacterium photorhabdus luminescens than newly ecdysed fifth-stage (day 0) caterpillars. the decrease in ins ... | 2008 | 18001766 |
| the biology and genome of heterorhabditis bacteriophora. | heterorhabditis bacteriophora is an entomopathogenic nematode (epn) mutually associated with the enteric bacterium, photorhabdus luminescens, used globally for the biological control of insects. much of the previous research concerning h. bacteriophora has dealt with applied aspects related to biological control. however, h. bacteriophora is an excellent model to investigate fundamental processes such as parasitism and mutualism in addition to its comparative value to caenorhabditis elegans. in ... | 2007 | 18050499 |
| the hcar regulatory protein of photorhabdus luminescens affects the production of proteins involved in oxidative stress and toxemia. | comparison of the proteomes of wild-type photorhabdus luminescens and its hcar derivative, grown in insect hemolymph, showed that hcar disruption decreased the production of toxins (tcda1, mcf, and pirab) and proteins involved in oxidative stress response (soda, ahpc, gor). the disruption of hcar did not affect growth rate in insects, but did delay the virulence of p. luminescens in bombyx mori and spodoptera littoralis larvae. this delayed virulence was associated with a lower toxemia rather th ... | 2007 | 18072208 |
| a metagenomic analysis of soil bacteria extends the diversity of quorum-quenching lactonases. | a metagenomic library of 10,121 clones, generated from bacteria inhabiting a pasture soil from france, was screened for the presence of fosmids conferring either n-acylhomoserine lactone (nahl) synthesis or nahl degradation ability upon their escherichia coli host. no clone producing nahls was identified whereas one, containing a 31 972 bp insert in fosmid p2h8, allowed nahl degradation. this led to the cloning and identification of a gene, qlca, encoding an nahl-lactonase activity, as judged by ... | 2008 | 18201196 |
| comparative analysis of the photorhabdus luminescens and the yersinia enterocolitica genomes: uncovering candidate genes involved in insect pathogenicity. | photorhabdus luminescens and yersinia enterocolitica are both enteric bacteria which are associated with insects. p. luminescens lives in symbiosis with soil nematodes and is highly pathogenic towards insects but not to humans. in contrast, y. enterocolitica is widely found in the environment and mainly known to cause gastroenteritis in men, but has only recently been shown to be also toxic for insects. it is expected that both pathogens share an overlap of genetic determinants that play a role ... | 2008 | 18221513 |
| cinnamic acid, an autoinducer of its own biosynthesis, is processed via hca enzymes in photorhabdus luminescens. | photorhabdus luminescens, an entomopathogenic bacterium and nematode symbiont, has homologues of the hca and mhp enzymes. in escherichia coli, these enzymes catalyze the degradation of the aromatic compounds 3-phenylpropionate (3pp) and cinnamic acid (ca) and allow the use of 3pp as sole carbon source. p. luminescens is not able to use 3pp and ca as sole carbon sources but can degrade them. hca dioxygenase is involved in this degradation pathway. p. luminescens synthesizes ca from phenylalanine ... | 2008 | 18245247 |
| regulatory role of uvry in adaptation of photorhabdus luminescens growth inside the insect. | we report global expression profiling of a uvry-deficient mutant of photorhabdus luminescens. we found that the regulator moiety of the two-component regulatory system bara/uvry regulated more than 500 target genes coding for functions involved in the synthesis of major compartments and metabolic pathways of the cell. this regulation appeared to be in part indirect as uvry affected the expression of several regulators. indeed, the flagellum biosynthesis transcription activator flhc and the flage ... | 2008 | 18248456 |
| cell invasion and matricide during photorhabdus luminescens transmission by heterorhabditis bacteriophora nematodes. | many animals and plants have symbiotic relationships with beneficial bacteria. experimentally tractable models are necessary to understand the processes involved in the selective transmission of symbiotic bacteria. one such model is the transmission of the insect-pathogenic bacterial symbionts photorhabdus spp. by heterorhabditis bacteriophora infective juvenile (ij)-stage nematodes. by observing egg-laying behavior and ij development, it was determined that ijs develop exclusively via intrauter ... | 2008 | 18281425 |
| pathogenic effect of entomopathogenic nematode-bacterium complexes on terrestrial isopods. | in this study, we evaluated the effect of entomopathogenic nematodes (epns) steinernema carpocapsae, steinernema feltiae and heterorhabditis bacteriophora, symbiotically associated with bacteria of the genera xenorhabdus or photorhabdus, on the survival of eight terrestrial isopod species. the epn species s. carpocapsae and h. bacteriophora reduced the survival of six isopod species while s. feltiae reduced survival for two species. two terrestrial isopod species tested (armadillidium vulgare an ... | 2008 | 18346756 |
| isolation and identification of entomopathogenic nematodes and their symbiotic bacteria from hérault and gard (southern france). | isolation and identification of native nematode-bacterial associations in the field are necessary for successful control of endemic pests in a particular location. no study has yet been undertaken to recover and identify epn in metropolitan france. in the present paper, we provide results of a survey of epn and their symbiotic bacteria conducted in hérault and gard regions in southern france. molecular characterization of isolated nematodes depicted three different steinernema species and one he ... | 2008 | 18353356 |
| effects of entomopathogenic bacterium photorhabdus temperata infection on the intestinal microbiota of the sugarcane stalk borer diatraea saccharalis (lepidoptera: crambidae). | photorhabdus temperata is an entomopathogenic bacterium that is associated with nematodes of the heterorhabditidae family in a symbiotic relationship. this study investigated the effects of p. temperata infection on the intestinal microbiota of the sugarcane stalk borer diatraea saccharalis. histopathology of the infection was also investigated using scanning electron microscopy. groups of 20 larvae were infected by injection of approximately 50 bacterial cells directly into the hemocoel. after ... | 2008 | 18406423 |
| expression and activity of a probable toxin from photorhabdus luminescens. | as an insect pathogen, photorhabdus luminescens possesses an arsenal of toxins. here we cloned and expressed a probable toxin from p. luminescens subsp. akhurstii ynd185, designated as photorhabdus insecticidal toxin (pit). the pit gene shares 94% nucleotide and 98% predicted amino acid sequence identity with plu1537, a predicted orf from p. luminescens subsp. laumondii tt01 and 30% predicted amino acid sequence similarity to a fragment of a 13.6 kda insecticidal crystal protein gene of bacillus ... | 2009 | 18409059 |
| molecular analysis of a novel gene cluster encoding an insect toxin in plant-associated strains of pseudomonas fluorescens. | pseudomonas fluorescens cha0 and the related strain pf-5 are well-characterized representatives of rhizosphere bacteria that have the capacity to protect crop plants from fungal root diseases, mainly by releasing a variety of exoproducts that are toxic to plant pathogenic fungi. here, we report that the two plant-beneficial pseudomonads also exhibit potent insecticidal activity. anti-insect activity is linked to a novel genomic locus encoding a large protein toxin termed fit (for p. fluorescensi ... | 2008 | 18484997 |
| photorhabdus luminescens genes induced upon insect infection. | photorhabdus luminescens is a gram-negative luminescent enterobacterium and a symbiote to soil nematodes belonging to the species heterorhabditis bacteriophora. p.luminescens is simultaneously highly pathogenic to insects. this bacterium exhibits a complex life cycle, including one symbiotic stage characterized by colonization of the upper nematode gut, and a pathogenic stage, characterized by release from the nematode into the hemocoel of insect larvae, resulting in rapid insect death caused by ... | 2008 | 18489737 |
| mutualistic association of photorhabdus asymbiotica with japanese heterorhabditid entomopathogenic nematodes. | gram-negative bacteria, photorhabdus luminescens and p. temperata, form a mutualistic association with entomopathogenic heterorhabditid nematodes while p. asymbiotica is known as an opportunistic human pathogen that causes disseminated bacteremic spread on two continents, the united states and australia. in the course of our phylogenetic study of photorhabdus bacteria associated with japanese heterorhabditis nematodes, we found two photorhabdus isolates (photorhabdus sp. cbkj163 and onir40) whos ... | 2008 | 18538616 |
| photorhabdus: a model for the analysis of pathogenicity and mutualism. | photorhabdus are entomopathogenic members of the family enterobacteriaceae. in addition to killing insects photorhabdus also have a mutualistic association with nematodes from the family heterorhabditidiae. therefore, the bacteria have a complex life cycle that involves temporally separated pathogenic and mutualistic associations with two different invertebrate hosts. this tripartite photorhabdus-insect-nematode association provides researchers with a unique opportunity to characterize the proka ... | 2008 | 18647173 |
| plastic architecture of bacterial genome revealed by comparative genomics of photorhabdus variants. | the phenotypic consequences of large genomic architecture modifications within a clonal bacterial population are rarely evaluated because of the difficulties associated with using molecular approaches in a mixed population. bacterial variants frequently arise among photorhabdus luminescens, a nematode-symbiotic and insect-pathogenic bacterium. we therefore studied genome plasticity within photorhabdus variants. | 2008 | 18647395 |
| variable length tandem repeat polyglutamine sequences in the flexible tether region of the tsr chemotaxis receptor of escherichia coli. | methyl-accepting chemotaxis proteins (mcps) are receptors that play an important role in bacterial chemotaxis. methylation of tsr, the mcp that mediates chemotaxis towards serine in escherichia coli, is thought to be facilitated by binding of the methyltransferase to a flexible tether region at the c-terminal end of tsr. this study analysed natural length variants of the tether that occur in e. coli due to genetic instability in tandem repeat dna sequences that code for glutaminyl (q) residues, ... | 2008 | 18667570 |
| host-derived extracellular nucleic acids enhance innate immune responses, induce coagulation, and prolong survival upon infection in insects. | extracellular nucleic acids play important roles in human immunity and hemostasis by inducing ifn production, entrapping pathogens in neutrophil extracellular traps, and providing procoagulant cofactor templates for induced contact activation during mammalian blood clotting. in this study, we investigated the functions of extracellular rna and dna in innate immunity and hemolymph coagulation in insects using the greater wax moth galleria mellonella a reliable model host for many insect and human ... | 2008 | 18684961 |
| application of 16s rdna-dgge and plate culture to characterization of bacterial communities associated with the sawfly, acantholyda erythrocephala (hymenoptera, pamphiliidae). | culture-based analysis was employed in parallel with pcr amplification of 16s rdna, coupled with denaturing gradient gel electrophoresis (dgge), to profile bacterial species associated with different developmental stages of the pine false webworm (pfw), acantholyda erythrocephala, a sawfly pest responsible for incidents of severe defoliation in commercially important tree plantations in north america. culture-based analysis revealed that pseudomonas spp. along with bacillus sphaericus and arthro ... | 2008 | 18769850 |
| comparative analysis of anti-restriction activities of arda (colib-p9) and ocr (t7) proteins. | anti-restriction proteins arda and ocr are specific inhibitors of type i restriction-modification enzymes. the inci1 transmissible plasmid colib-p9 arda and bacteriophage t7 0.3(ocr) genes were cloned in puc18 vector. both arda (colib-p9) and ocr (t7) proteins inhibit both restriction and modification activities of the type i restriction-modification enzyme (ecoki) in escherichia coli k12 cells. colib-p9 arda, t7 0.3(ocr), and the photorhabdus luminescens luxcdabe genes were cloned in pz-series ... | 2008 | 18774937 |
| effects of entomopathogenic bacterium photorhabdus temperata infection on the digestive enzymes of diatraea saccharalis (lepidoptera: crambidae) larvae. | this study investigated the effects of photorhabdus temperata infection on the activities of digestive enzymes of the sugarcane stalk borer diatraea saccharalis. non-infected d. saccharalis larvae present a major alpha-amylase, several proteinases, three sucrose hydrolases and two alpha-glucosidases in their midgut. analysis of these hydrolases by electrophoresis and "in gel" assays showed that the activities of all enzymes decreased following infection, with an initial decline observed 12 h aft ... | 2008 | 18782059 |
| motility is required for the competitive fitness of entomopathogenic photorhabdus luminescens during insect infection. | photorhabdus are motile members of the family enterobactericeae that are pathogenic to insect larvae whilst also maintaining a mutualistic interaction with entomophagous nematodes of the family heterorhabditiae. the interactions between photorhabdus and its hosts are thought to be an obligate part of the bacteria's life-cycle in the environment. motility often plays a key role in mediating bacteria-host interactions and, in this study, we were interested in characterising the role of motility in ... | 2008 | 18834522 |
| cloning and heterologous expression of insecticidal-protein-encoding genes from photorhabdus luminescens tt01 in enterobacter cloacae for termite control. | enterobacter cloacae, one of the indigenous gut bacteria of the formosan subterranean termite (coptotermes formosanus), was genetically modified with a transposon tn5 vector containing genes (tcda1 and tcdb1) encoding orally insecticidal proteins from the entomopathogenic bacterium photorhabdus luminescens subsp. laumondii tt01, a symbiont of the entomopathogenic nematode heterorhabditis bacteriophora, for termite control. in the laboratory, termites were fed filter paper inoculated with the rec ... | 2008 | 18836027 |
| rapid virulence annotation (rva): identification of virulence factors using a bacterial genome library and multiple invertebrate hosts. | current sequence databases now contain numerous whole genome sequences of pathogenic bacteria. however, many of the predicted genes lack any functional annotation. we describe an assumption-free approach, rapid virulence annotation (rva), for the high-throughput parallel screening of genomic libraries against four different taxa: insects, nematodes, amoeba, and mammalian macrophages. these hosts represent different aspects of both the vertebrate and invertebrate immune system. here, we apply rva ... | 2008 | 18838673 |
| effects of dietary supplementation with an expressed fusion peptide bovine lactoferricin-lactoferrampin on performance, immune function and intestinal mucosal morphology in piglets weaned at age 21 d. | lactoferrin has antimicrobial activity associated with peptide fragments lactoferricin (lfc) and lactoferrampin (lfa) released on digestion. these two fragments have been expressed in photorhabdus luminescens as a fusion peptide linked to protein cipb. the construct cipb-lfc-lfa was tested as an alternative to antimicrobial growth promoters in pig production. sixty piglets with an average live body weight of 5.42 (sem 0.59) kg were challenged with enterotoxigenic escherichia coli and randomly as ... | 2009 | 18840311 |
| the yersinia pseudotuberculosis and yersinia pestis toxin complex is active against cultured mammalian cells. | the toxin complex (tc) genes were first identified in the insect pathogen photorhabdus luminescens and encode approximately 1 mda protein complexes which are toxic to insect pests. subsequent genome sequencing projects have revealed the presence of tc orthologues in a range of bacterial pathogens known to be associated with insects. interestingly, members of the mammalian-pathogenic yersiniae have also been shown to encode tc orthologues. studies in yersinia enterocolitica have shown that diverg ... | 2008 | 18957603 |
| whole-cell biodetection of halogenated organic acids. | a whole-cell bacterial sensor system for short-chain halo-organic acids was constructed, using 2-chloropropionic acid (2-cpa) as a model pollutant. an escherichia coli host was transformed with a moderate-copy plasmid containing a fusion of two foreign genetic elements: (a) a promoter-containing segment of the pseudomonas dl-dex (dl-2-haloacid dehalogenase) encoding gene and (b) bioluminescence (luxcdabe) genes of photorhabdus luminescens. the resulting construct, named mt1, responded to the pre ... | 2001 | 18968446 |
| photorhabdus temperata subsp. cinerea subsp. nov., isolated from heterorhabditis nematodes. | during the characterization of symbiotic bacteria of hungarian entomopathogenic nematode isolates, a number of bacteria (including strain 3107(t)) isolated from heterorhabditis downesi and heterorhabditis megidis showed only moderate 16s rrna gene sequence similarity to the type strains of all described photorhabdus species and subspecies. on the basis of the 16s rrna gene sequence, the phylogenetic relationships of these isolates were uncertain, because of the low bootstrap values. using gyrb s ... | 2008 | 18984696 |
| effect of carvedilol on the production of reactive oxygen species by hl-60 cells. | the generation of reactive oxygen species (ros) by phagocytes is one of the irreplaceable microbicidal tools of innate immunity. it has been reported in our previous studies that short-term treatment by carvedilol ex vivo inhibits ros generation. the purpose of this study was to investigate the long-term effect of carvedilol on phagocytes. | 2008 | 18987604 |
| a destabilized bacterial luciferase for dynamic gene expression studies. | fusions of genetic regulatory elements with reporter genes have long been used as tools for monitoring gene expression and have become a major component in synthetic gene circuit implementation. a major limitation of many of these systems is the relatively long half-life of the reporter protein(s), which prevents monitoring both the initiation and the termination of transcription in real-time. furthermore, when used as components in synthetic gene circuits, the long time constants associated wit ... | 2007 | 19003433 |
| [induction of oxidative stress and sos response in escherichia coli by plant extracts: the role of hydroperoxides and the synergistic effect of simultaneous treatment with cisplatinum]. | plasmids containing a transcription fusion of escherichia coli katg, soxs, and resa promoters to the photorhabdus luminescens lux operon (luxcdabe) were constructed. the bioluminescence method of assessing oxidative stress and sos response in e. coli cells was applied to test the genotoxicity of cisplatinum and vegetable extracts. strains mg1655 (pkatg-lux) and mg1655 (psoxs-lux) were used in the oxidative stress procedure. strain mg1655(preca-lux) was used to test the genotoxicity of the chemic ... | 2008 | 19004338 |
| the emerging human pathogen photorhabdus asymbiotica is a facultative intracellular bacterium and induces apoptosis of macrophage-like cells. | photorhabdus species are gram-negative entomopathogenic bacteria of the family enterobacteriaceae. among the different members of the genus, one species, photorhabdus asymbiotica, is a pathogen of both insects and humans. the pathogenicity mechanisms of this bacterium are unknown. here we show that p. asymbiotica is a facultative intracellular pathogen that is able to replicate inside human macrophage-like cells. furthermore, p. asymbiotica was shown for the first time in an intracellular locati ... | 2009 | 19075024 |
| cellular reporter screens for inhibitors of burkholderia pseudomallei targets in pseudomonas aeruginosa. | to facilitate the discovery of new therapeutics for burkholderia pseudomallei infections, we have developed cellular reporter screens for inhibitors of b. pseudomallei targets in the surrogate host pseudomonas aeruginosa. pseudomonas aeruginosa strains carrying deletions of essential genes were engineered to be dependent on the isopropyl-beta-d-thiogalactopyranoside (iptg)-regulated expression of their b. pseudomallei orthologues on a broad-host-range plasmid. pseudomonas aeruginosa genes which ... | 2008 | 19121678 |
| effect of ph, edta, and anions on heavy metal toxicity toward a bioluminescent cyanobacterial bioreporter. | the bioavailability and therefore toxicity of a metal depends on the chemical species present in a particular environment. we evaluated the effect of a series of factors that could potentially modify metal speciation on the toxicity of hg, cu, zn, and cd toward a recombinant strain of the freshwater cyanobacterium anabaena sp. pcc 7120 with cloned lux operon of luminescent terrestrial bacterium photorhabdus luminescens. the strain, denoted as anabaena cpb4337, showed a high constitutive luminesc ... | 2009 | 19169738 |
| heterorhabditis gerrardi n. sp. (nematoda: heterorhabditidae): the hidden host of photorhabdus asymbiotica (enterobacteriaceae: gamma-proteobacteria). | a new entomopathogenic nematode species from australia, heterorhabditis gerrardi n. sp. (nematoda: heterorhabditidae) is described. morphological and molecular studies together with cross-hybridization tests indicated that this nematode represents a new undescribed species, closely related to members in the 'indica-group'. however, the new species can be distinguished from other species in this genus by a combination of several qualitative and quantitative morphological traits. key diagnostic fe ... | 2009 | 19216823 |
| a bacterial type iii effector family uses the papain-like hydrolytic activity to arrest the host cell cycle. | pathogenic bacteria deliver effector proteins into host cells through the type iii secretion apparatus to modulate the host function. we identify a family of proteins, homologous to the type iii effector cif from enteropathogenic escherichia coli, in pathogens including yersinia, photorhabdus, and burkholderia that contain functional type iii secretion systems. like cif, this family of proteins is capable of arresting the host cell cycle at g(2)/m. structure of one of the family members, cif hom ... | 2009 | 19225106 |
| a single locus from the entomopathogenic bacterium photorhabdus luminescens inhibits activated manduca sexta phenoloxidase. | insect blood (hemolymph) contains prophenoloxidase, a proenzyme that is activated to protective phenoloxidase when the insect is damaged or challenged with microorganisms. the gram-negative bacterium photorhabdus luminescens kills the lepidopteron insect manduca sexta by using a variety of toxins. we screened p. luminescens and photorhabdus asymbiotica cosmid libraries in an escherichia coli host against previously activated m. sexta hemolymph phenoloxidase and identified three overlapping cosmi ... | 2009 | 19243439 |
| insecticidal toxic proteins produced by photorhabdus luminescens akhurstii, a symbiont of heterorhabditis indica. | we describe the isolation and characterization of an insect pathogenic bacterium from the entomopathogenic nematode heterorhabditis indica (karnataka strain), an isolate from the southern regions of india. the strain has been identified and characterized by phenotypic, biochemical tests and pcr-rflp analysis of the 16s rrna gene as photorhabdus luminescens subsp. akhurstii. the insecticidal toxin complex produced by this bacterium has been purified through a series of steps including ultrafiltra ... | 2002 | 19265903 |
| cycle inhibiting factors (cifs) are a growing family of functional cyclomodulins present in invertebrate and mammal bacterial pathogens. | the cycle inhibiting factor (cif) produced by enteropathogenic and enterohemorrhagic escherichia coli was the first cyclomodulin to be identified that is injected into host cells via the type iii secretion machinery. cif provokes cytopathic effects characterized by g(1) and g(2) cell cycle arrests, accumulation of the cyclin-dependent kinase inhibitors (ckis) p21(waf1/cip1) and p27(kip1) and formation of actin stress fibres. the x-ray crystal structure of cif revealed it to be a divergent member ... | 2009 | 19308257 |
| isolation and activity of xenorhabdus antimicrobial compounds against the plant pathogens erwinia amylovora and phytophthora nicotianae. | broad-spectrum antibiotics produced by symbiotic bacteria [entomopathogenic bacterium (epb)] of entomopathogenic nematodes keep monoxenic conditions in insect cadavers in soil. this study evaluated antibiotics produced by epb for their potential to control plant pathogenic bacteria and oomycetes. | 2009 | 19320949 |
| ecotoxicity assessment of lipid regulators in water and biologically treated wastewater using three aquatic organisms. | the high consumption of blood lipid regulators is leading to frequent reports of the occurrence of fibrates in natural streams and wastewater effluents. this paper describes a study undertaken to evaluate the acute toxicity of bezafibrate, clofibric acid, gemfibrozil, and fenofibric acid, a metabolite of fenofibrate whose ecotoxicity has not been previously reported. | 2010 | 19333638 |
| [antirestriction and antimodification activities of the t7 ocr protein: effect of mutations in interface]. | antirestriction protein ocr (bacteriophage t7) is specific inhibitor of the type i restriction-modification enzymes. the bacteriophage t7 0.3 (ocr) gene is cloned in puc18 vector. it was shown that t7 ocr protein inhibits both restriction and modification activities of the type i restriction-modification enzyme (ecoki) in escherichia coli k12 cells. the mutation form of ocr-ocr f53d a57e, which inhibits only the restriction activity of ecoki-enzyme, was constructed. the t7 0.3 (ocr) and the phot ... | 2009 | 19334532 |
| entomopathogenic bacteria as a source of secondary metabolites. | insects are not only the most diverse group of animals on our planet, but also a huge reservoir for unusual microorganism which are a rich source of pharmaceutically interesting natural products. this review focuses on recent advances in the understanding of secondary metabolism of bacillus thuringiensis, pseudomonas entomophila, and xenorhabdus and photorhabdus bacteria all of which are entomopathogenic. genome-sequencing projects revealed the capacity of these bacteria to produce several diffe ... | 2009 | 19345136 |
| masters of conquest and pillage: xenorhabdus nematophila global regulators control transitions from virulence to nutrient acquisition. | invertebrate animal models are experimentally tractable and have immunity and disease symptoms that mirror those of vertebrates. therefore they are of particular utility in understanding fundamental aspects of pathogenesis. indeed, artificial models using human pathogens and invertebrate hosts have revealed conserved and novel molecular mechanisms of bacterial infection and host immune responses. additional insights may be gained from investigating interactions between invertebrates and pathogen ... | 2009 | 19374654 |
| identification and characterization of a novel gene involved in the trans-specific nematicidal activity of photorhabdus luminescens ln2. | photorhabdus luminescens subsp. akhurstii ln2 from heterorhabditis indica ln2 showed nematicidal activity against axenic heterorhabditis bacteriophora h06 infective juveniles (ijs). transposon mutagenesis identified an ln2 mutant that supports the growth of h06 nematodes. tn5 disrupted the nama gene, encoding a novel 364-residue protein and involving the nematicidal activity. the green fluorescent protein-labeled nama mutant was unable to colonize the intestines of h06 ijs. | 2009 | 19376907 |