Publications

[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
transcriptomic analysis of the entomopathogenic nematode heterorhabditis bacteriophora tto1.	the entomopathogenic nematode heterorhabditis bacteriophora and its symbiotic bacterium, photorhabdus luminescens, are important biological control agents of insect pests. this nematode-bacterium-insect association represents an emerging tripartite model for research on mutualistic and parasitic symbioses. elucidation of mechanisms underlying these biological processes may serve as a foundation for improving the biological control potential of the nematode-bacterium complex. this large-scale exp ...	2009	19405965
a suite of recombinant luminescent bacterial strains for the quantification of bioavailable heavy metals and toxicity testing.	recombinant whole-cell sensors have already proven useful in the assessment of the bioavailability of environmental pollutants like heavy metals and organic compounds. in this work 19 recombinant bacterial strains representing various gram-positive (staphylococcus aureus and bacillus subtilis) and gram-negative (escherichia coli, pseudomonas fluorescens) bacteria were constructed to express the luminescence encoding genes luxcdabe (from photorhabdus luminescens) as a response to bioavailable hea ...	2009	19426479
pirab toxin from photorhabdus asymbiotica as a larvicide against dengue vectors.	we have evaluated photorhabdus insect-related protein (pir) from photorhabdus asymbiotica against dengue vectors. pirab shows larvicidal activity against both aedes aegypti and aedes albopictus larvae but did not affect the mesocyclops thermocyclopoides predator. pirab expressed the strongest toxicity compared to pira, pirb, or the mixture of pira plus pirb. whether the presence of an enterobacterial repetitive intergenic consensus sequence in pirab, but not in pira, pirb, or the mixture of pira ...	2009	19429564
crystal structures of cif from bacterial pathogens photorhabdus luminescens and burkholderia pseudomallei.	a pre-requisite for bacterial pathogenesis is the successful interaction of a pathogen with a host. one mechanism used by a broad range of gram negative bacterial pathogens is to deliver effector proteins directly into host cells through a dedicated type iii secretion system where they modulate host cell function. the cycle inhibiting factor (cif) family of effector proteins, identified in a growing number of pathogens that harbour functional type iii secretion systems and have a wide host range ...	2009	19440549
comparison of bacteroides thetaiotaomicron and escherichia coli 16s rrna gene expression signals.	there are barriers to cross-expression of genes between bacteroides spp. and escherichia coli. in this study, a lux-based reporter system was developed for bacteroides and used to compare the promoter structure and function of a bacteroides thetaiotaomicron 4001 (bt4001) 16s rrna promoter with those of e. coli in vivo. analysis of the bt4001 sequences upstream of the 16s rrna gene revealed the same overall structure known for e. coli 16s rrna promoters in that there were two promoters separated ...	2009	19443545
heterologous expression of bacillus thuringiensis vegetative insecticidal protein-encoding gene vip3lb in photorhabdus temperata strain k122 and oral toxicity against the lepidoptera ephestia kuehniella and spodoptera littoralis.	photorhabdus temperata and bacillus thuringiensis are entomopathogenic bacteria exhibiting toxicities against different insect larvae. vegetative insecticidal protein vip3lb is a bacillus thuringiensis insecticidal protein secreted during the vegetative growth stage exhibiting lepidopteran specificity. in this study, we focused for the first time on the heterologous expression of vip3lb gene in photorhabdus temperata strain k122. firstly, western blot analyses of whole cultures of recombinant ph ...	2009	19462262
plasmatocyte-spreading peptide (psp) plays a central role in insect cellular immune defenses against bacterial infection.	insect hemocytes (blood cells) are a central part of the insect's cellular response to bacterial pathogens, and these specialist cells can both recognize and engulf bacteria. during this process, hemocytes undergo poorly characterized changes in adhesiveness. previously, a peptide termed plasmatocyte-spreading peptide (psp), which induces the adhesion and spreading of plasmatocytes on foreign surfaces, has been identified in lepidopteran insects. here, we investigate the function of this peptide ...	2009	19483002
novel antibiotic compounds produced by the insect pathogenic bacterium photorhabdus.	phototorhabdus is an insect pathogenic enterobacterium which maintains a mutualistic interaction with heterorhabditid nematodes. while the bacteria live in the nematode gut, the nematodes live in the soil and infect insect larvae, releasing their symbiotic bacteria into the insect blood. here the bacteria reproduce and kill the insect by septicaemia. the nematodes then feed on the bacterial biomass and undergo several rounds of reproduction before emerging from the cadaver carrying their bacteri ...	2009	19519542
induced nitric oxide synthesis in the gut of manduca sexta protects against oral infection by the bacterial pathogen photorhabdus luminescens.	injecting the insect pathogenic bacterium photorhabdus luminescens into the blood system of the model lepidopteran insect manduca sexta induces nitric oxide synthase (nos) expression in the fat body and blood cells (haemocytes), whereas following oral ingestion of bacteria nos expression is limited to the gut. we used rna interference to knock-down expression of nos throughout the insect. preventing nos induction in this way adversely affected the survival of orally infected insects and caused a ...	2009	19538546
photorhabdus and a host of hosts.	photorhabdus is a member of the family enterobacteriaceae that lives in a mutualistic association with a heterorhabditis nematode worm. the nematode worm burrows into insect prey and regurgitates photorhabdus, which goes on to kill the insect. the nematode feeds off the growing bacteria until the insect tissues are exhausted, whereupon they reassociate and leave the cadaver in search of new prey. this highly efficient partnership has been used for many years as a biological crop protection agent ...	2009	19575559
comparative genomics of the emerging human pathogen photorhabdus asymbiotica with the insect pathogen photorhabdus luminescens.	the gram-negative bacterium photorhabdus asymbiotica (pa) has been recovered from human infections in both north america and australia. recently, pa has been shown to have a nematode vector that can also infect insects, like its sister species the insect pathogen p. luminescens (pl). to understand the relationship between pathogenicity to insects and humans in photorhabdus we have sequenced the complete genome of pa strain atcc43949 from north america. this strain (formerly referred to as xenorh ...	2009	19583835
drosophila embryos as model systems for monitoring bacterial infection in real time.	drosophila embryos are well studied developmental microcosms that have been used extensively as models for early development and more recently wound repair. here we extend this work by looking at embryos as model systems for following bacterial infection in real time. we examine the behaviour of injected pathogenic (photorhabdus asymbiotica) and non-pathogenic (escherichia coli) bacteria and their interaction with embryonic hemocytes using time-lapse confocal microscopy. we find that embryonic h ...	2009	19609447
the bordetella type iii secretion system effector btea contains a conserved n-terminal motif that guides bacterial virulence factors to lipid rafts.	the bordetella type iii secretion system (t3ss) effector protein btea is necessary and sufficient for rapid cytotoxicity in a wide range of mammalian cells. we show that btea is highly conserved and functionally interchangeable between bordetella bronchiseptica, bordetella pertussis and bordetella parapertussis. the identification of btea sequences required for cytotoxicity allowed the construction of non-cytotoxic mutants for localization studies. btea derivatives were targeted to lipid rafts a ...	2009	19650828
bioluminescent monitoring of in vivo colonization and clearance dynamics by light-emitting bacteria.	bioluminescence is an excellent reporter system for analysing bacterial colonization and clearance dynamics in vivo. many bacterial species have been rendered bioluminescent, allowing the sensitive detection of bacterial burden and metabolic activity in real-time and in situ in living animals. in this chapter we describe the protocols for characterizing in vivo infection models using bioluminescent bacteria: from real-time imaging in living animals by bioluminescence imaging (bli) to ex vivo bli ...	2009	19685306
comparative in vivo gene expression of the closely related bacteria photorhabdus temperata and xenorhabdus koppenhoeferi upon infection of the same insect host, rhizotrogus majalis.	photorhabdus and xenorhabdus are gram-negative, phylogenetically related, enterobacteria, forming mutualism with the entomopathogenic nematodes heterorhabditis and steinernema, respectively. the mutualistic bacteria living in the intestines of the nematode infective juveniles are pathogenic to the insect upon release by the nematodes into the insect hemolymph. such a switch needs activation of genes that promote bacterial virulence. we studied in vivo gene expression in photorhabdus temperata an ...	2009	19754939
the dlt operon of bacillus cereus is required for resistance to cationic antimicrobial peptides and for virulence in insects.	the dlt operon encodes proteins that alanylate teichoic acids, the major components of cell walls of gram-positive bacteria. this generates a net positive charge on bacterial cell walls, repulsing positively charged molecules and conferring resistance to animal and human cationic antimicrobial peptides (amps) in gram-positive pathogenic bacteria. amps damage the bacterial membrane and are the most effective components of the humoral immune response against bacteria. we investigated the role of t ...	2009	19767427
phylogeny of photorhabdus and xenorhabdus based on universally conserved protein-coding sequences and implications for the taxonomy of these two genera. proposal of new taxa: x. vietnamensis sp. nov., p. luminescens subsp. caribbeanensis subsp. nov., p. luminescens subsp. hainanensis subsp. nov., p. temperata subsp. khanii subsp. nov., p. temperata subsp. tasmaniensis subsp. nov., and the reclassification of p. luminescens subsp. thracensis as p. temperata subsp. thracensis comb. nov.	we used the information from a set of concatenated sequences from four genes (reca, gyrb, dnan and gltx) to investigate the phylogeny of the genera photorhabdus and xenorhabdus (entomopathogenic bacteria associated with nematodes of the genera heterorhabditis and steinernema, respectively). the robustness of the phylogenetic tree obtained by this multigene approach was significantly better than that of the tree obtained by a single gene approach. the comparison of the topologies of single gene p ...	2010	19783607
lysozymes and lysozyme-like proteins from the fall armyworm, spodoptera frugiperda.	lysozyme is an important component of the insect non-specific immune response against bacteria that is characterized by its ability to break down bacterial cell-walls. by searching an est database from the fall armyworm, spodoptera frugiperda (negre et al., 2006), we identified five sequences encoding proteins of the lysozyme family. the deduced protein sequences corresponded to three classical c-type lysozymes sf-lys1, sf-lys2 and sf-lys3, and two lysozyme-like proteins, sf-llp1 and sf-llp2. sf ...	2009	19828200
frank kunst, 1943-2009.		2009	19843231
in vivo bioluminescence imaging for the study of intestinal colonization by escherichia coli in mice.	bioluminescence imaging (bli) is emerging as a powerful tool for real-time monitoring of infections in living animals. however, since luciferases are oxygenases, it has been suggested that the requirement for oxygen may limit the use of bli in anaerobic environments, such as the lumen of the gut. strains of escherichia coli harboring the genes for either the bacterial luciferase from photorhabdus luminescens or the ppyre-ts and ppygr-ts firefly luciferase mutants of photinus pyralis (red and gre ...	2010	19880653
optimization of bacterial whole cell bioreporters for toxicity assay of environmental samples.	in a study to optimize bacterial whole cell biosensors (bioreporters) for the detection of environmental contaminants, we constructed a toxicity sensing strain acinetobacter baylyi adp1_reca_lux. the adp1_reca_lux is a chromosomally based bioreporter which makes the sensing system stable and negates the need for antibiotics to maintain the trait. the aop1_reca_lux is activated to express bioluminescence when it is exposed to dna damaging toxicants. since the adp1_reca_lux constantly expresses a ...	2009	19921916
regulating alternative lifestyles in entomopathogenic bacteria.	bacteria belonging to the genera photorhabdus and xenorhabdus participate in a trilateral symbiosis in which they enable their nematode hosts to parasitize insect larvae. the bacteria switch from persisting peacefully in a nematode's digestive tract to a lifestyle in which pathways to produce insecticidal toxins, degrading enzymes to digest the insect for consumption, and antibiotics to ward off bacterial and fungal competitors are activated. this study addresses three questions: (1) what molecu ...	2010	20022247
recent insight into the pathogenicity mechanisms of the emergent pathogen photorhabdus asymbiotica.	photorhabdus asymbiotica is unique among the entomopathogenic bacteria of this genus in also being able to infect humans, leading to its isolation from some clinical samples. recent comparative genomics data and the results of studies of interactions between bacteria and cells provide insight into the adaptation of this bacterium to its new niche, the human body.	2010	20034588
a putative mobile genetic element carrying a novel type iif restriction-modification system (pluti).	genome comparison and genome context analysis were used to find a putative mobile element in the genome of photorhabdus luminescens, an entomopathogenic bacterium. the element is composed of 16-bp direct repeats in the terminal regions, which are identical to a part of insertion sequences (iss), a dna methyltransferase gene homolog, two genes of unknown functions and an open reading frame (orf) (plu0599) encoding a protein with no detectable sequence similarity to any known protein. the orf (plu ...	2010	20071747
identification of genes involved in the mutualistic colonization of the nematode heterorhabditis bacteriophora by the bacterium photorhabdus luminescens.	photorhabdus are gram negative entomopathogenic bacteria that also have a mutualistic association with nematodes from the family heterorhabditis. an essential part of this symbiosis is the ability of the bacterium to colonize the gut of the freeliving form of the nematode called the infective juvenile (ij). although the colonization process (also called transmission) has been described phenomonologically very little is known about the underlying molecular mechanisms. therefore, in this study, we ...	2010	20149243
host-pathogen interactions: proline gives insect pathogens the green light.	how does a quiescent symbiont of a nematode worm know when to turn nasty? metabolic analysis and genetic knockouts confirm that model insect pathogens can sense l-proline in insect blood. this not only serves as a wake-up call, activating secondary metabolite virulence factors, but also provides an energy source for a metabolic shift appropriate for adaptation to the host environment.	2010	20152135
the draft genome sequence of arsenophonus nasoniae, son-killer bacterium of nasonia vitripennis, reveals genes associated with virulence and symbiosis.	four percent of female nasonia vitripennis carry the son-killer bacterium arsenophonus nasoniae, a microbe with notably different biology from other inherited parasites and symbionts. in this paper, we examine a draft genome sequence of the bacterium for open reading frames (orfs), structures and pathways involved in interactions with its insect host. the genome data suggest that a. nasoniae carries multiple type iii secretion systems, and an array of toxin and virulence genes found in photorhab ...	2010	20167018
frequency and diversity of small cryptic plasmids in the genus rahnella.	rahnella is a widely distributed genus belonging to the enterobacteriaceae and frequently present on vegetables. although rahnella has interesting agro-economical and industrial properties and several strains possess antibiotic resistances and toxin genes which might spread within microbial communities, little is known about plasmids of this genus. thus, we isolated a number of rahnella strains and investigated their complements of small plasmids.	2010	20170524
significant deviations in the configurations of homologous tandem repeats in prokaryotic genomes.	we explored the possibilities of whole-genome duplication (wgd) in prokaryotic species, where we performed statistical analyses of the configurations of the central angles between homologous tandem repeats (trs) on the circular chromosomes. at first, we detected trs on their chromosomes and identified equivalent tandem repeat pairs (etrps); here, an etrp is defined as a pair of tandem repeats sequentially similar to each other. then we carried out statistical analyses of the central angle distri ...	2009	20172489
discovery and characterization of inhibitors of pseudomonas aeruginosa type iii secretion.	the type iii secretion system (t3ss) is a clinically important virulence mechanism in pseudomonas aeruginosa that secretes and translocates up to four protein toxin effectors into human cells, facilitating the establishment and dissemination of infections. to discover inhibitors of this important virulence mechanism, we developed two cellular reporter assays and applied them to a library of 80,000 compounds. the primary screen was based on the dependence of the transcription of t3ss operons on t ...	2010	20176902
photox, a novel actin-targeting mono-adp-ribosyltransferase from photorhabdus luminescens.	photorhabdus luminescens is a pathogenic bacterium that produces many toxic proteins. the mono-adp-ribosyltransferases (marts) are an enzyme class produced by numerous pathogenic bacteria and participate in disease in plants and animals, including humans. herein we report a novel mart from p. luminescens called photox. this 46-kda toxin shows high homology to other actin-targeting marts in hallmark catalytic regions and a similar core catalytic fold. furthermore, photox shows in vivo cytotoxic a ...	2010	20181945
photorhabdus luminescens toxins adp-ribosylate actin and rhoa to force actin clustering.	the bacterium photorhabdus luminescens is mutualistically associated with entomopathogenetic nematodes. these nematodes invade insect larvae and release the bacteria from their intestine, which kills the insects through the action of toxin complexes. we elucidated the mode of action of two of these insecticidal toxins from p. luminescens. we identified the biologically active components tccc3 and tccc5 as adenosine diphosphate (adp)-ribosyltransferases, which modify unusual amino acids. tccc3 ad ...	2010	20185726
phylogeny of gammaproteobacteria.	the phylogeny of the large bacterial class gammaproteobacteria has been difficult to resolve. here we apply a telescoping multiprotein approach to the problem for 104 diverse gammaproteobacterial genomes, based on a set of 356 protein families for the whole class and even larger sets for each of four cohesive subregions of the tree. although the deepest divergences were resistant to full resolution, some surprising patterns were strongly supported. a representative of the acidithiobacillales rou ...	2010	20207755
use of luminescent leptospira interrogans for enumeration in biological assays.	rapid and reliable in vitro methods for the detection of pathogenic leptospires, such as leptospira interrogans, are lacking. the present study investigated the use of luminescence to replace the existing enumeration techniques. transposon tnsc189 was modified to incorporate the luxcdabe cassette from photorhabdus luminescens and was used to construct luminescent leptospira spp. there was a linear relationship between luminescence and cell number, with the theoretical detection limit being less ...	2010	20375235
[evaluation of the phagocytic activity of human peripheral blood neutrophils, by employing recombinant luminescent bacteria].	the authors show it possible to evaluate the phagocytic activity of human peripheral blood neutrophils from their impact on the fluorescence intensity of recombinant luminescent bacteria. they have established the preferred use of recombinant luminescent escherichia coli bacteria with cloned luxcdabe genes of photobacterium leiognathii as phagocyted objects and substantiated the optimal method of their opsonization by normal human immunoglobulin. the variants of separate consideration of the lum ...	2010	20401994
photorhabdus adhesion modification protein (pam) binds extracellular polysaccharide and alters bacterial attachment.	photorhabdus are gram-negative nematode-symbiotic and insect-pathogenic bacteria. the species photorhabdus asymbiotica is able to infect humans as well as insects. we investigated the secreted proteome of a clinical isolate of p. asymbiotica at different temperatures in order to identify proteins relevant to the infection of the two different hosts.	2010	20462430
probing the tri-trophic interaction between insects, nematodes and photorhabdus.	summary: photorhabdus sp. are entomopathogenic bacteria which, upon experimental infection, interact with the insect immune system, but little is known about the roles of their symbiotic nematode partners heterorhabditis sp. in natural infections. here, we investigated the respective contributions of nematodes and bacteria by examining humoral and cellular immune reactions of the model lepidopteran insect manduca sexta against heterorhabditis carrying photorhabdus, nematodes free of bacteria (ax ...	2010	20500922
high-level expression, purification and antibacterial activity of bovine lactoferricin and lactoferrampin in photorhabdus luminescens.	bovine lactoferricin (lfc) and bovine lactoferrampin (lfa) are two active fragments located in the n(1)-domain of bovine lactoferrin. recent studies suggested that lfc and lfa have broad-spectrum activity against gram-positive and gram-negative bacteria. to date, lfc and lfa have usually been produced from milk. we report here the high-level expression, purification and characterization of lfc and lfa using the photorhabdus luminescens expression system. after the cipa and cipb genes were delete ...	2010	20510367
influence of soil fumigation by methyl bromide and methyl iodide on rhizosphere and phyllosphere microbial community structure.	rhizosphere and phyllosphere microbial communities were evaluated on roots and leaves of growth chamber-grown lettuce (lactuca sativa (l.) cv. green forest) plants by culture-dependent and -independent methods after soil fumigation. denaturing gradient gel electrophoresis (dgge) with 16s rrna primers followed by cloning and sequencing was used to identify major rrna bands from the rhizosphere and phyllosphere. three weeks after fumigation, there were no differences (p = 0.16) in rhizosphere micr ...	2010	20512733
exploiting a global regulator for small molecule discovery in photorhabdus luminescens.	bacterially produced small molecules demonstrate a remarkable range of structural and functional diversity and include some of our most useful biological probes and therapeutic agents. annotations of bacterial genomes reveal a large gap between the number of known small molecules and the number of biosynthetic genes/loci that could produce such small molecules, a gap that most likely originates from tight regulatory control by the producing organism. this study coupled a global transcriptional r ...	2010	20524642
identification and characterization of a novel l-amino acid ligase from photorhabdus luminescens subsp. laumondii tt01.	l-amino acid ligase catalyzes dipeptide synthesis from unprotected l-amino acids in an atp-dependent manner. we recently identified a new member of l-amino acid ligase, the plu1440 protein, from photorhabdus luminescens subsp. laumondii tt01 by in silico analysis. this protein was found to synthesize dipeptides containing l-asparagine at the n-terminus, which is a novel substrate specificity.	2010	20541113
the role of iron uptake in pathogenicity and symbiosis in photorhabdus luminescens tt01.	photorhabdus are gram negative bacteria that are pathogenic to insect larvae whilst also having a mutualistic interaction with nematodes from the family heterorhabditis. iron is an essential nutrient and bacteria have different mechanisms for obtaining both the ferrous (fe2+) and ferric (fe3+) forms of this metal from their environments. in this study we were interested in analyzing the role of fe3+ and fe2+ iron uptake systems in the ability of photorhabdus to interact with its invertebrate hos ...	2010	20569430
photorhabdus phase variants express a novel fimbrial locus, mad, essential for symbiosis.	summary fimbriae are adhesive organelles known to enable pathogens to colonize animal tissue, but little is known of their function in mutualistic symbioses. photorhabdus colonization of heterorhabditis bacteriophora nematodes is essential for the pair's insect pathogenic lifestyle. maternal nematodes acquire photorhabdus symbionts as a persistent intestinal biofilm prior to transmission to infective juvenile (ij) stage offspring developing inside the maternal body. screening 8000 photorhabdus m ...	2010	20572934
[antibiotics produced by photorhabdus luminescens zmi, a symbiont of entomopathogenic nematodes].	a novel strain of photorhabdus luminescens zmi isolated from nematode larvae heterorhabditis sp. was shown to produce antibiotic complexes with antibacterial and antifungal activities. the antibiotic complexes secreted extracellularly and intracellularly were separated into individual components. comparison of their properties with the databases for biologically active compounds suggested that component a was identical to 3,5-dihydroxy-4-isopropylstilbene, components b and h belonged to anthraqu ...	2009	20583561
new plasmids and putative virulence factors from the draft genome of an australian clinical isolate of photorhabdus asymbiotica.	clinical isolates of photorhabdus asymbiotica have been recovered from patients in both the united states of america and australia, and the full sequence of p. asymbiotica atcc43949 from the united states has been reported recently. in contrast to other bacteria in the genus that only infect insects, p. asymbiotica strains are able to infect both insects and humans. using a combination of solexa (illumina) and 454 life sciences (roche) sequence data in different assembly pipelines, we report on ...	2010	20584081
role of matrix metalloproteinase zmp-2 in pathogen resistance and development in caenorhabditis elegans.	the genome of caenorhabditis elegans includes six homologs of matrix metalloproteinases (mmps). the c. elegans mmp gene zmp-1 has recently been shown to be involved in anchor cell invasion during post-embryonic vulval development. here, we identified h19m22.3 (zmp-2) as a pleiotropic mmp gene regulating disease resistance, molting, larval development, and fecundity. zmp-2(rnai) nematodes showed significant lifespan reduction during infection with pathogenic photorhabdus luminescence. moreover, w ...	2010	20600277
construction of a bioluminescence reporter plasmid for francisella tularensis.	a francisella tularensis shuttle vector that constitutively expresses the photorhabdus luminescens lux operon in type a and type b strains of f. tularensis was constructed. the bioluminescence reporter plasmid was introduced into the live vaccine strain of f. tularensis and used to follow f. tularensis growth in a murine intranasal challenge model in real-time by bioluminescence imaging. the results show that the new bioluminescence reporter plasmid represents a useful tool for tularemia researc ...	2010	20620161
imd pathway is involved in the interaction of drosophila melanogaster with the entomopathogenic bacteria, xenorhabdus nematophila and photorhabdus luminescens.	xenorhabdus nematophila/steinernema carpocapsae and photorhabdus luminescens/heterorhabditis bacteriophora are nemato-bacterial complexes highly pathogenic for insects. using a syringe as artificial vector, we have analyzed the effects of the two bacteria, x. nematophila and p. luminescens on the genetic tool insect, drosophila melanogaster. both bacteria were found to kill adult flies in a dose dependent manner with x. nematophila being the fastest. on the other hand, when an injection of non-p ...	2010	20627393
a metabolic switch is involved in lifestyle decisions in photorhabdus luminescens.	photorhabdus luminescens is a species of gram-negative bacteria that is pathogenic to insects while also maintaining a mutualistic association with nematodes from the family heterorhabditis. p. luminescens elaborates an extensive secondary metabolism during the post-exponential phase of growth that includes the production of an antibiotic called 3-5-dihydroxy-4-isopropylstilbene (st), an anthraquinone pigment (aq) and bioluminescence. in this study we identified a mutant that was unable to produ ...	2010	20662779
photorhabdus luminescens subsp. kleinii subsp. nov. (enterobacteriales: enterobacteriaceae).	association between bacteria photorhabdus and their nematode hosts heterorhabditis represents one of the emerging models in symbiosis studies. in this study, we isolated the bacterial symbionts of the nematode heterorhabditis georgiana. using gyrb sequences for phylogenetic analysis, these strains were shown to be part of the species of photorhbdus luminescens but with clear separation from currently recognized subspecies. physiological properties and dna-dna hybridization profiles also supporte ...	2011	20717672
a robust phylogenetic framework for the bacterial genus photorhabdus and its use in studying the evolution and maintenance of bioluminescence: a case for 16s, gyrb, and glna.	photorhabdus spp., the only known bioluminescent terrestrial bacteria are well known for their symbiotic association with heterorhabditid nematodes. this association, along with their ability to kill insects, has aroused interest in the evolutionary relationships within this bacterial group. currently, three species are recognized within the genus photorhabdus; p. temperata and p. luminescens, which are endosymbionts of heterorhabditis spp., and p. asymbiotica, which has been isolated from human ...	2010	20732433
proteolytic enzyme production by strains of the insect pathogen xenorhabdus and characterization of an early-log-phase-secreted protease as a potential virulence factor.	as a comparison to a similar study on photorhabdus strains, 15 xenorhabdus bacterial strains and secondary phenotypic variants of two strains were screened for proteolytic activity by five detection methods. although the number and intensity of proteolytic activities were different, every strain was positive for proteolytic activity by several tests. zymography following native page detected two groups of activities with different substrate affinities and a higher and lower electrophoretic mobil ...	2010	20802071
the bacterial effector cif interferes with scf ubiquitin ligase function by inhibiting deneddylation of cullin1.	cycle inhibiting factor (cif) is one of the effectors delivered into epithelial cells by enteropathogenic escherichia coli (epec) and enterohemorrhagic escherichia coli (ehec) via the type iii secretion system (ttss). cif family proteins, which inhibit host cell-cycle progression via mechanisms not yet precisely understood, are highly conserved among epec, ehec, yersinia pseudotuberculosis, photorhabdus luminescens and burkholderia pseudomallei. levels of several proteins relevant to cell-cycle ...	2010	20850415
photorhabdus temperata subsp. stackebrandtii subsp. nov. (enterobacteriales: enterobacteriaceae).	the bacterial symbiont of the entomopathogenic nematode heterorhabditis bacteriophora strain gps11 was characterized by 16s rrna gene sequence and physiological traits. the phylogenetic tree built upon 16s rrna gene sequences clustered the gps11 bacterial isolate with photorhabdus temperata strains which have been previously isolated from heterorhabditis species. the phylogenetic tree further identified four subgroups in p. temperata, and the relationships among these subgroups were confirmed by ...	2010	20852981
a path from predation to mutualism.	luminescent bacteria and nematodes associate in a strategy where the bacteria act as virulent pathogens of insects, used as their food supply, while the nematodes graze on them. upon reaching high density, the bacteria produce light and metabolites that turn the nematodes into hosts permitting them to be carried over to further nematode preys. in this issue of molecular microbiology, lango and clarke show that the corresponding shift in lifestyle is triggered by a metabolic switch closely linked ...	2010	20860087
the cyclomodulin cif of photorhabdus luminescens inhibits insect cell proliferation and triggers host cell death by apoptosis.	cycle inhibiting factors (cif) constitute a broad family of cyclomodulins present in bacterial pathogens of invertebrates and mammals. cif proteins are thought to be type iii effectors capable of arresting the cell cycle at g(2)/m phase transition in human cell lines. we report here the first direct functional analysis of cif(pl), from the entomopathogenic bacterium photorhabdus luminescens, in its insect host. the cif(pl) gene was expressed in p. luminescens cultures in vitro. the resulting pro ...	2010	20870031
the kdpd/kdpe two-component system of photorhabdus asymbiotica promotes bacterial survival within m. sexta hemocytes.	many bacteria persist within phagocytes, deploying complex sets of tightly regulated virulence factors to manipulate and survive within host cells. so far, no single factor has been identified that is sufficient to allow intracellular persistence of an otherwise non-pathogenic bacterium. here we report that the two-component kdpd/kdpe sensor kinase/response regulator of the insect and human pathogen photorhabdus asymbiotica (pa) is sufficient to allow a harmless laboratory strain of e. coli to r ...	2010	20932844
clotting factors and eicosanoids protect against nematode infections.	we show that hemolymph clotting protects drosophila melanogaster against infections with an entomopathogenic nematode and its symbiotic bacterium. we also provide biochemical and genetic evidence for an involvement of eicosanoids in the same infection model. taken together, our results confirm the conserved nature of the immune function of clot formation.	2010	20948189
upgrading bioluminescent bacterial bioreporter performance by splitting the lux operon.	bioluminescent bacterial bioreporters harbor a fusion of bacterial bioluminescence genes (luxcdabe), acting as the reporting element, to a stress-response promoter, serving as the sensing element. upon exposure to conditions that activate the promoter, such as an environmental stress or the presence of an inducing chemical, the promoter::reporter fusion generates a dose-dependent bioluminescent signal. in order to improve bioluminescent bioreporter performance we have split the luxcdabe genes of ...	2010	20949260
units of plasticity in bacterial genomes: new insight from the comparative genomics of two bacteria interacting with invertebrates, photorhabdus and xenorhabdus.	flexible genomes facilitate bacterial evolution and are classically organized into polymorphic strain-specific segments called regions of genomic plasticity (rgps). using a new web tool, rgpfinder, we investigated plasticity units in bacterial genomes, by exhaustive description of the rgps in two photorhabdus and two xenorhabdus strains, belonging to the enterobacteriaceae and interacting with invertebrates (insects and nematodes).	2010	20950463
molecular mechanisms of persistence of mutualistic bacteria photorhabdus in the entomopathogenic nematode host.	symbioses between microbes and animals are ubiquitous, yet little is known about the intricate mechanisms maintaining such associations. in an emerging mutualistic model system, insect-pathogenic bacteria photorhabdus and their insect-parasitic nematode partner heterorhabditis, we found that the bacteria undergo major transcriptional reshaping in the nematode intestine. besides general starvation mechanisms, the bacteria induce cellular acidification to slow down growth, switch to pentose phosph ...	2010	20957199
the ability of nisin f to control staphylococcus aureus infection in the peritoneal cavity, as studied in mice.	to determine the ability of nisin f to control systematic infection caused by staphylococcus aureus, using c57bl/6 mice as a model.	2010	21029139
dissecting the immune response to the entomopathogen photorhabdus.	bacterial pathogens either hide from or modulate the host's immune response to ensure their survival. photorhabdus is a potent insect pathogenic bacterium that uses entomopathogenic nematodes as vectors in a system that represents a useful tool for probing the molecular basis of immunity. during the course of infection, photorhabdus multiplies rapidly within the insect, producing a range of toxins that inhibit phagocytosis of the invading bacteria and eventually kill the insect host. photorhabdu ...	2010	21035345
targeting of the actin cytoskeleton by insecticidal toxins from photorhabdus luminescens.	photorhabdus luminescens produces several types of protein toxins, which are essential for participation in a trilateral symbiosis with nematodes and insects. the nematodes, carrying the bacteria, invade insect larvae and release the bacteria, which kill the insects with their toxins. recently, the molecular mechanisms of the toxin complexes ptc3 and ptc5 have been elucidated. the biologically active components of the toxin complexes are adp-ribosyltransferases, which modify actin and rho gtpase ...	2010	21072628
domain organization and evolution of multifunctional autoprocessing repeats-in-toxin (martx) toxin in vibrio vulnificus.	the objective of this study was to analyze multifunctional autoprocessing repeats-in-toxin (martx) toxin domain organization within the aquatic species vibrio vulnificus as well as to study the evolution of the rtxa1 gene. the species is subdivided into three biotypes that differ in host range and geographical distribution. we have found three different types (i, ii, and iii) of v. vulnificus martx (martx(vv)) toxins with common domains (an autocatalytic cysteine protease domain [cpd], an α/β-hy ...	2010	21075892
transcriptional analysis of a photorhabdus sp. variant reveals transcriptional control of phenotypic variation and multifactorial pathogenicity in insects.	photorhabdus luminescens lives in a mutualistic association with entomopathogenic nematodes and is pathogenic for insects. variants of photorhabdus frequently arise irreversibly and are studied because they have altered phenotypic traits that are potentially important for the host interaction. var* is a colonial and phenotypic variant displaying delayed pathogenicity when directly injected into the insect, spodoptera littoralis. in this study, we evaluated the role of transcriptomic modulation i ...	2010	21131515
influence of the photorhabdus luminescens phosphomannose isomerase gene, mana, on mannose utilization, exopolysaccharide structure, and biofilm formation.	extracellular polysaccharide (eps) is produced by diverse bacterial pathogens and fulfills assorted roles, including providing a structural matrix for biofilm formation and more specific functions in virulence, such as protection against immune defenses. we report here the first investigation of some of the genes important for biofilm formation in photorhabdus luminescens and demonstrate the key role of the phosphomannose isomerase gene, mana, in the structure of functional eps. phenotypic analy ...	2010	21148694
cholera- and anthrax-like toxins are among several new adp-ribosyltransferases.	chelt, a cholera-like toxin from vibrio cholerae, and certhrax, an anthrax-like toxin from bacillus cereus, are among six new bacterial protein toxins we identified and characterized using in silico and cell-based techniques. we also uncovered medically relevant toxins from mycobacterium avium and enterococcus faecalis. we found agriculturally relevant toxins in photorhabdus luminescens and vibrio splendidus. these toxins belong to the adp-ribosyltransferase family that has conserved structure d ...	2010	21170356
horse species symposium: a novel approach to monitoring pathogen progression during uterine and placental infection in the mare using bioluminescence imaging technology and lux-modified bacteria.	uterine and placental infections are the leading cause of abortion, stillbirth, and preterm delivery in the mare. whereas uterine and placental infections in women have been studied extensively, a comprehensive examination of the pathogenic processes leading to this unsatisfactory pregnancy outcome in the mare has yet to be completed. most information in the literature relating to late-term pregnancy loss in mares is based on retrospective studies of clinical cases submitted for necropsy. here w ...	2011	21239661
the first record of entomopathogenic nematodes (rhabiditiae: steinernematidae and heterorhabditidae) in natural ecosystems in lebanon: a biogeographic approach in the mediterranean region.	a survey of entomopathogenic nematodes in lebanon was conducted for the first time during 2008-2009. samples were collected on the coastal strip and in nine vegetation types extending from the coastal line to 3088m above sea level. wooded and herbaceous ecosystems were considered for sampling purposes. a total of 570 samples were taken, out of which 1% were positive for entomopathogenic nematodes. approximately, 15.8% out of the 19 sites sampled revealed entomopathogenic nematodes presence (repr ...	2011	21241704
construction of a novel bioluminescent reporter system for investigating shiga toxin expression of enterohemorrhagic escherichia coli.	a novel chromosome-plasmid hybrid bioluminescent reporter system (c-p reporter system) utilizing photorhabdus luminescens luxcdabe genes has been constructed to monitor the expression of shiga toxin 1 (stx1) and shiga toxin 2 (stx2) in enterohemorrhagic escherichia coli (ehec) in real time. the luxcdabe genes of p. luminescens have been cloned and divided into a luxcdab cassette and a luxe gene. a promoter-less luxe gene introduced downstream from stx1 and from stx2 on ehec chromosomes in single ...	2011	21262333
phylogenetic and cophylogenetic relationships of entomopathogenic nematodes (heterorhabditis: rhabditida) and their symbiotic bacteria (photorhabdus: enterobacteriaceae).	mutualistic association between entomopathogenic photorhabdus bacteria and heterorhabditis nematodes represents one of the emerging model systems in symbiosis studies, yet little is known about this partnership from a coevolutionary perspective. herein, we investigated phylogenetic and cophylogenetic relationships of heterorhabditis and photorhabdus strains using molecular markers internal transcribed spacer and gyrase b gene sequences, respectively. the phylogenies presented consistent, well su ...	2011	21335093
bioluminescent high-throughput assay for the bacteria adherence to the tissue culture cells.	the goal of this study was develop a rapid high-throughput method for the assessment of the bacterial adhesion to tissue culture cells and test this method by investigation of the adhesion and growth of pathogenic and non-pathogenic escherichia coli strains in the presence of hela human epithelial cells. fifteen strains of e. coli were transformed with a plasmid carrying the entire lux operon of photorhabdus luminescens to make them bioluminescent. by using the time-to-detection approach and bio ...	2011	21337328
swarming motility by photorhabdus temperata is influenced by environmental conditions and uses the same flagella as that used in swimming motility.	photorhabdus temperata, an insect pathogen and nematode symbiont, is motile in liquid medium by swimming. we found that p. temperata was capable of surface movement, termed swarming behavior. several lines of evidence indicate that p. temperata use the same flagella for both swimming and swarming motility. both motility types required additional nacl or kcl in the medium and had peritrichous flagella, which were composed of the same flagellin as detected by immunoblotting experiments. mutants de ...	2011	21358760
light producing reporter plasmids for escherichia coli k-12 that can be integrated into the chromosome.	plasmid vectors using the photorhabdus luminescenslux operon can be used for real time measurements of promoter activity. we have generated a series of lux vectors that have a conditional origin of replication, different selectable markers and the attp sequence from ?. single copies of these plasmids can be integrated into the ? attachment site in the escherichia coli chromosome. we constructed reporter derivatives and compared light production when the plasmids were present in multiple copies a ...	2011	21376749
an insect pathogenic symbiosis between a caenorhabditis and serratia.	we described an association between a strain of the nematode caenorhabditis briggsae, i.e. kt0001, and the bacteria serratia sp. scbi (south african caenorhabditis briggsae isolate), which was able to kill the insect galleria. here we show that the serratia sp. scbi lines the gut of the nematode, similar to the heterorhabditis-photorhabdus complex, indicating that the association is possibly internal. we also expand on the relevance of this tripartite, i.e. insect-nematode-bacteria, interaction ...	2011	21389770
a serine proteinase homologue, sph-3, plays a central role in insect immunity.	numerous vertebrate and invertebrate genes encode serine proteinase homologues (sphs) similar to members of the serine proteinase family, but lacking one or more residues of the catalytic triad. these sph proteins are thought to play a role in immunity, but their precise functions are poorly understood. in this study, we show that sph-3 (an insect non-clip domain-containing sph) is of central importance in the immune response of a model lepidopteran, manduca sexta. we examine m. sexta infection ...	2011	21398604
the occurrence of photorhabdus-like toxin complexes in bacillus thuringiensis.	recently, genomic sequencing of a bacillus thuringiensis (bt) isolate from our collection revealed the presence of an apparent operon encoding an insecticidal toxin complex (tca) similar to that first described from the entomopathogen photorhabdus luminescens. to determine whether these genes are widespread among bt strains, we screened isolates from the collection for the presence of tccc, one of the genes needed for the expression of fully functional toxin complexes. among 81 isolates chosen t ...	2011	21464948
actin as target for modification by bacterial protein toxins.	various bacterial protein toxins and effectors target the actin cytoskeleton. at least three groups of toxins/effectors can be identified, which directly modify actin molecules. one group of toxins/effectors causes adp-ribosylation of actin at arginine-177, thereby inhibiting actin polymerization. members of this group are numerous binary actin-adp-ribosylating exotoxins (e.g. clostridium botulinum c2 toxin) as well as several bacterial adp-ribosyltransferases (e.g. salmonella enterica spvb) whi ...	2011	21466657
assessing the influence of the entomopathogenic nematode heterorhabditis baujardi lpp7 (rhabiditina) on embryogenesis and hatching of the plant-parasitic nematode meloidogyne mayaguensis (tylenchina).	two assays were conducted to assess the influence of infective juveniles (ijs) of heterorhabditis baujardi lpp7 on the embryogenesis and hatching of meloidogyne mayaguensis. in the first assay, eggs were incubated in water alone or in the presence of infective juveniles, and completion of embryogenesis was evaluated 14days later. in the second assay, unhatched second-stage juveniles were incubated in distilled water alone or in the presence of infective juveniles. cumulative hatching was compare ...	2011	21514301
insecticidal toxin complex proteins from xenorhabdus nematophilus: structure and pore formation.	toxin complexes from xenorhabdus or photorhabdus spp. bacteria represent novel insecticidal proteins. we have purified a native toxin complex (toxin complex 1) from xenorhabdus nematophilus. the toxin complex is composed of three different proteins; xpta2, xptb1, and xptc1 representing products from class a, b and c toxin complex genes, respectively. we show that recombinant xpta2, and co-produced recombinant xptb1 and xptc1 bind together with a 4:1:1 stoichiometry. xpta2 forms a tetramer of ~1, ...	2011	21527640
the xnp1 p2-like tail synthesis gene cluster encodes xenorhabdicin and is required for interspecies competition.	xenorhabdus nematophila, the mutualistic bacterium of the nematode steinernema carpocapsae, produces the r-type bacteriocin called xenorhabdicin that is thought to confer a competitive advantage for growth in the insect host. we have identified a p2-like tail synthesis gene cluster (xnp1) that was required for xenorhabdicin production. the xnp1 genes were expressed constitutively during growth and were induced by mitomycin c. deletion of either the sheath (xnps1) or fiber (xnph1) genes eliminate ...	2011	21602326
enzymatic characterization of a serralysin-like metalloprotease from the entomopathogen bacterium, xenorhabdus.	we investigated the enzymatic properties of a serralysin-type metalloenzyme, provisionally named as protease b, which is secreted by xenorhabdus bacterium, and probably is the ortholog of pra peptidase of photorhabdus bacterium. testing the activity on twenty-two oligopeptide substrates we found that protease b requires at least three amino acids n-terminal to the scissile bond for detectable hydrolysis. on such substrate protease b was clearly specific for positively charged residues (arg and l ...	2011	21635975
overcoming the production limitations of photorhabdus temperata ssp. temperata strain k122 bioinsecticides in low-cost medium.	for low-cost production of photorhabdus temperata ssp. temperata strain k122 bioinsecticide, a cheap complex medium was optimized. diluted seawater was used as the source of micronutrients, especially sodium chloride, involved in the improvement of cell density, culturability and oral toxicity of the bacterium p. temperata against ephestia kuehniella larvae. thus, the new formulated medium was composed only of 10 g/l of soya bean meal, used as the carbon and nitrogen main source, mixed in sevenf ...	2011	21656156
genomic analysis reveals versatile organisms for quorum quenching enzymes: acyl-homoserine lactone-acylase and -lactonase.	microbial virulence and their resistance to multiple drugs have obliged researchers to look for novel drug targets. virulence of pathogenic microbes is regulated by signal molecules such as acylated homoserine lactone (ahl) produced during a cell density dependent phenomenon of quorum sensing (qs). in contrast, certain microbes produce ahl-lactonases and -acylases to degrade qs signals, also termed as quorum quenching. mining sequenced genome databases has revealed organisms possessing conserved ...	2011	21660112
detection of dichloromethane with a bioluminescent (lux) bacterial bioreporter.	the focus of this research effort was to develop an autonomous, inducible, lux-based bioluminescent bioreporter for the real-time detection of dichloromethane. dichloromethane (dcm), also known as methylene chloride, is a volatile organic compound and one of the most commonly used halogenated solvents in the u.s., with applications ranging from grease and paint stripping to aerosol propellants and pharmaceutical tablet coatings. predictably, it is released into the environment where it contamina ...	2011	21688172
purl gene expression affects biofilm formation and symbiotic persistence of photorhabdus temperata in the nematode heterorhabditis bacteriophora.	extensive studies of the well-known legume and rhizobium symbiosis model system suggest that the purine metabolic pathway plays a key role in microbe-plant interactions, although the exact mechanism is unknown. here, we report the impact of a key purine metabolic gene, purl, on the symbiotic interaction between the bacterium photorhabdus temperata and its nematode partner heterorhabditis bacteriophora. real-time pcr assays showed that the purl gene was upregulated in p. temperata in the nematode ...	2011	21700665
16s rdna-based phylogeny of non-symbiotic bacteria of entorno-pathogenic nematodes from infected insect cadavers.	using 16s rdna gene sequencing technique, three different species of non-symbiotic bacteria of entomopatho-genic nematodes (epns) (steinernema sp. and heterorhabditis sp.) were isolated and identified from infected insect cadavers {galleria mellonella larvae) after 48-hour post infections. sequence similarity analysis revealed that the strains srk3, srk4 and srk5 belong to ochrobactrum cytisi, schineria larvae and ochrobactrum anthropi, respectively. the isolates o. anthropi and s. larvae were f ...	2011	21802047
low structural diversity of the o-polysaccharides of photorhabdus asymbiotica subspp. asymbiotica and australis and their similarity to the o-polysaccharides of taxonomically remote bacteria including francisella tularensis.	the o-polysaccharides were isolated from the lipopolysaccharides of emerging human pathogens photorhabdus asymbiotica subsp. asymbiotica us-86 and us-87 and subsp. australis au36, au46, and au92. studies by sugar analysis and (1)h and (13)c nmr spectroscopy before and after o-deacetylation showed that the o-polysaccharide structures are essentially identical within, and only slightly different between, the subspecies. the following structures of the repeating units of the o-polysaccharides were ...	2011	21816392
application of bacterial bioluminescence to assess the efficacy of fast-acting biocides.	traditional microbiological techniques are used to provide reliable data on the rate and extent of kill for a range of biocides. however, such techniques provide very limited data regarding the initial rate of kill of fast-acting biocides over very short time domains. this study describes the application of a recombinant strain of escherichia coli expressing the photorhabdus luminescens lux operon as a whole-cell biosensor. light emission is linked directly to bacterial metabolism; therefore, by ...	2011	21876044
submerged monoxenic culture medium development for heterorhabditis bacteriophora and its symbiotic bacterium photorhabdus luminescens: protein sources.	most medium formulations for improving culture of entomopathogenic nematodes (epn) based on protein sources have used enriched media like animal feed such as dried egg yolk, lactalbumin, and liver extract, among other ingredients. most results, however, showed unstable yields and longer production time. many of the results do not show the detailed parameters of fermentation. soy flour, cotton seed flour, corn gluten meal, casein powder, soytone, peptone, casein hydrolysates, and lactalbumin hydr ...	2011	21876379
the regulation of secondary metabolism and mutualism in the insect pathogenic bacterium photorhabdus luminescens.	photorhabdus is a genus of insect-pathogenic gram-negative bacteria that also maintain a mutualistic interaction with nematodes from the family heterorhabditis. this complex life cycle, involving different interactions with different invertebrate hosts, coupled with the amenability of the system to laboratory culture has resulted in the development of photorhabdus as a model system for studying bacterial-host interactions. photorhabdus is predicted to have an extensive secondary metabolism with ...	2011	21924970
dihydrophenylalanine: a prephenate-derived photorhabdus luminescens antibiotic and intermediate in dihydrostilbene biosynthesis.	2,5-dihydrophenylalanine (h(2)phe) is a multipotent nonproteinogenic amino acid produced by various actinobacteria and gammaproteobacteria. although the metabolite was discovered over 40 years ago, details of its biosynthesis have remained largely unknown. we show here that l-h(2)phe is a secreted metabolite in photorhabdus luminescens cultures and a precursor of a recently described 2,5-dihydrostilbene. bioinformatic analysis suggested a candidate gene cluster for the processing of prephenate t ...	2011	21944749
functional characterization and biological significance of yersinia pestis lipopolysaccharide biosynthesis genes.	in silico analysis of available bacterial genomes revealed the phylogenetic proximity levels of enzymes responsible for biosynthesis of lipopolysaccharide (lps) of yersinia pestis, the cause of plague, to homologous proteins of closely related yersinia spp. and some other bacteria (serratia proteamaculans, erwinia carotovora, burkholderia dolosa, photorhabdus luminescens and others). isogenic y. pestis mutants with single or double mutations in 14 genes of lps biosynthetic pathways were construc ...	2011	21999543
oral toxicity of photorhabdus culture media on gene expression of the adult sweetpotato whitefly, bemisia tabaci.	the oral toxicity of culture media of the symbiotic bacteria, photorhabdus temperata, mutually associated with entomopathogenic nematode heterorhabditis megidis and photorhabdus luminescens ssp. laumondii (tt01) mutually associated with heterorhabditis bacteriophora, were investigated in the adults of bemisia tabaci. the oral ingestion of sucrose diet solutions (20%) containing bacteria-free supernatant of the culture media from symbiotic bacteria gradually increased mortalities and was complete ...	2012	22041203
Detection and Identification of Species-Specific Bacteria Associated with Synanthropic Mites.	Internal bacterial communities of synanthropic mites Acarus siro, Dermatophagoides farinae, Lepidoglyphus destructor, and Tyrophagus putrescentiae (Acari: Astigmata) were analyzed by culturing and culture-independent approaches from specimens obtained from laboratory colonies. Homogenates of surface-sterilized mites were used for cultivation on non-selective agar and DNA extraction. Isolated bacteria were identified by sequencing of the 16S rRNA gene. PCR amplified 16S rRNA genes were analyzed b ...	2011	22057398