| the role of guanosine-3',5'-bis-pyrophosphate in mediating antimicrobial activity of the antibiotic 3,5-dihydroxy-4-ethyl-trans-stilbene. | the mode of action of 3,5-dihydroxy-4-ethyl-trans-stilbene (es), an antibiotic produced by xenorhabdus luminescens symbiotically associated with an entomopathogenic nematode, was investigated. es was active against gram-positive and a number of gram-negative bacteria. in susceptible bacteria this antibiotic caused the inhibition of total rna synthesis and, to a lesser extent, protein synthesis. at or above mics, es triggered a substantial accumulation of an intracellular regulatory compound, gua ... | 1992 | 1282791 |
| lysogeny and bacteriocinogeny in xenorhabdus nematophilus and other xenorhabdus spp. | induction by mitomycin or high-temperature treatment resulted in the production of bacteriocins and phages in both phases of xenorhabdus nematophilus a24, indicating lysogeny. phage dna purified from x. nematophilus a24 hybridized to several fragments of drai-digested a24 chromosomal dna, confirming that the phage genome was incorporated into the bacterial chromosome. bacteriocins and phages were detected in cultures of most other xenorhabdus spp. after mitomycin or high-temperature treatment. x ... | 1992 | 1444417 |
| fatty acid-enhanced binding of flavin mononucleotide to bacterial luciferase measured by steady-state fluorescence. | bacterial luciferase catalyzes the oxidation of reduced flavin mononucleotide and tetradecanal resulting in the emission of light. we have investigated the interactions of a recombinant luciferase from a terrestrial bacterium xenorhabdus luminescens with the reaction products, fmn and myristic acid, using steady-state fluorescence spectroscopy. quenching of the intrinsic fluorescence and fmn fluorescence on binding of fmn to luciferase was found to be greatly stimulated in the presence of myrist ... | 1992 | 1445293 |
| characterization of form variants of xenorhabdus luminescens. | from xenorhabdus luminescens xe-87.3 four variants were isolated. one, which produced a red pigment and antibiotics, was luminescent, and could take up dye from culture media, was considered the primary form (xe-red). a pink-pigmented variant (xe-pink) differed from the primary form only in pigmentation and uptake of dye. of the two other variants, one produced a yellow pigment and fewer antibiotics (xe-yellow), while the other did not produce a pigment or antibiotics (xe-white). both were less ... | 1992 | 1622273 |
| pathogenicity of xenorhabdus luminescens. | | 1992 | 1633985 |
| molecular cloning and characterization of the lux genes from the secondary form of xenorhabdus luminescens, k122. | | 1992 | 1633988 |
| multiple repetitive elements and organization of the lux operons of luminescent terrestrial bacteria. | the complete nucleotide sequences of the luxa to luxe genes, as well as the flanking regions, were determined for the lux operons of two xenorhabdus luminescens strains isolated from insects and humans. the nucleotide sequences of the corresponding lux genes (luxcdabe) were 85 to 90% identical but completely diverged 350 bp upstream of the first lux gene (luxc) and immediately downstream of the last lux gene (luxe). these results show that the luxg gene found immediately downstream of luxe in lu ... | 1992 | 1644764 |
| development of species-specific hybridization probes for marine luminous bacteria by using in vitro dna amplification. | by using two highly conserved region of the luxa gene as primers, polymerase chain reaction amplification methods were used to prepare species-specific probes against the luciferase gene from four major groups of marine luminous bacteria. laboratory studies with test strains indicated that three of the four probes cross-reacted with themselves and with one or more of the other species at low stringencies but were specific for members of their own species at high stringencies. the fourth probe, g ... | 1991 | 1854194 |
| cloning and nucleotide sequences of lux genes and characterization of luciferase of xenorhabdus luminescens from a human wound. | xenorhabdus luminescens hw is the only known luminous bacterium isolated from a human (wound) source. a recombinant plasmid was constructed that contained the x. luminescens hw luxa and luxb genes, encoding the luciferase alpha and beta subunits, respectively, as well as luxc, luxd, and a portion of luxe. the nucleotide sequences of these lux genes, organized in the order luxcdabe, were determined, and overexpression of the cloned luciferase genes was achieved in escherichia coli host cells. the ... | 1991 | 1995589 |
| nucleotide sequence, expression, and properties of luciferase coded by lux genes from a terrestrial bacterium. | the lux genes required for expression of luminescence have been cloned from a terrestrial bacterium, xenorhabdus luminescens, and the nucleotide sequences of the luxa and luxb genes coding for the alpha and beta subunits of luciferase determined. the lux gene organization was closely related to that of marine bacteria from the vibrio genus with the luxd gene being located immediately upstream and the luxe downstream of the luciferase genes, luxab. a high degree of homology (85% identity) was fou ... | 1990 | 2204626 |
| cloning, organization, and expression of the bioluminescence genes of xenorhabdus luminescens. | the lux genes of xenorhabdus luminescens, a symbiont of the nematode heterorhabditis bacteriophora, were cloned and expressed in escherichia coli. the expression of these genes in e. coli was qualitatively similar to their expression in x. luminescens. the organization of the genes is similar to that found in the marine luminous bacteria. hybridization studies with the dna that codes for the two subunits of luciferase revealed considerable homology among all of the strains of x. luminescens and ... | 1990 | 2211511 |
| the nucleotide sequence of the luxd gene of xenorhabdus luminescens hm. | | 1990 | 2216747 |
| development and application of oligonucleotide probes for molecular identification of xenorhabdus species. | synthetic deoxyoligonucleotide probes that hybridized against the region at positions 455 through 480 of 16s rrna were developed for the identification of all five xenorhabdus species. sequence variation in the respective rrna region between two strains of xenorhabdus luminescens in addition allowed the construction of two strain-specific probes. of 27 isolates determined to be xenorhabdus strains by phenotypic characterization, 24 could be assigned to four of the five species. two strains (hl-1 ... | 1990 | 2310180 |
| the nucleotide sequence of the luxa and luxb genes of xenorhabdus luminescens hm and a comparison of the amino acid sequences of luciferases from four species of bioluminescent bacteria. | the luxa and luxb genes of bioluminescent bacteria encode the alpha and beta subunits of luciferase, respectively. sequences of the luxa and luxb genes of xenorhabdus luminescens, the only terrestrial bioluminescent bacterium known, were determined and the amino acid sequence of luciferase deduced. the alpha subunit was found to contain 360 amino acids and has a calculated molecular weight of 41,005 da, while the beta subunit contains 327 amino acids and has a calculated molecular weight of 37,6 ... | 1990 | 2383248 |
| growth and luminescence of the bacterium xenorhabdus luminescens from a human wound. | xenorhabdus luminescens, a newly isolated luminous bacterium collected from a human wound, was characterized. the effects of ionic strength, temperature, oxygen, and iron on growth and development of the bioluminescent system were studied. the bacteria grew and emitted light best at 33 degrees c in a medium with low salt, and the medium after growth of cells to a high density was found to have antibiotic activity. the emission spectrum peaked at 482 nm in vivo and at 490 nm in vitro. both growth ... | 1989 | 2604398 |
| bioluminescence of the insect pathogen xenorhabdus luminescens. | luminescence of batch cultures of xenorhabdus luminescens was maximal when cultures approached stationary phase; the onset of in vivo luminescence coincided with a burst of synthesis of bacterial luciferase, the enzyme responsible for luminescence. expression of luciferase was aldehyde limited at all stages of growth, although more so during the preinduction phase. luciferase was purified from cultures of x. luminescens hm to a specific activity of 4.6 x 10(13) guanta/s per mg of protein and fou ... | 1989 | 2604399 |
| xenorhabdus luminescens (dna hybridization group 5) from human clinical specimens. | an unusual isolate from a human leg wound was identified as xenorhabdus luminescens. this finding led to the discovery or isolation of four additional strains, two from blood and two from wounds. three of the five strains were from patients in san antonio, tex. three strains were studied by dna-dna hybridization (s1 nuclease-trichloroacetic acid method) and were 77 to 100% related to each other, 34% related to the type strain of x. luminescens, 35 to 40% related to three of grimont's other dna h ... | 1989 | 2768446 |
| preliminary observations of a bacteriophage infecting xenorhabdus luminescens (enterobacteriaceae). | a bacteriophage infective to xenorhabdus luminescens, a bacterial symbiont of heterorhabditid nematodes, was recovered from insects that supported poor nematode development. plaque tests showed the phage particles to be infective only to primary and not secondary colonies of x. luminescens. the phage was not infective to x. nematophilus primaries or secondaries. the bacteriophage particles ranged 80-90 nm in length, with the head ranging from 40 to 50 nm in diameter. restriction analysis was per ... | 1989 | 2920806 |
| identification of an anthraquinone pigment and a hydroxystilbene antibiotic from xenorhabdus luminescens. | the entomopathogenic bacterium xenorhabdus luminescens produces a red pigment and an antibiotic in insect carcasses in which it grows and in axenic cultures. the pigment was purified and identified as the anthraquinone derivative 1,6-dihydroxy-4-methoxy-9,10-anthraquinone, which exhibits a ph-sensitive color change, i.e., it is yellow below ph 9 and red above ph 9. the antibiotic was also purified and identified as the hydroxystilbene derivative 3,5-dihydroxy-4-isopropylstilbene. | 1988 | 3415225 |
| neoaplectana species: specificity of association with bacteria of the genus xenorhabdus. | each of five neoaplectana (nematoda: steinernematidae) species was cultured monoxenically with various xenorhabdus (eubacteriales: enterobacteriaceae) isolates. the nematodes were usually able to reproduce when cultured with the bacterial symbiont of any one of the five neoaplectana spp. but never with xenorhabdus luminescens, symbiotic with heterorhabditis spp., or with the xenorhabdus sp. isolated from an undescribed steinernematid species. only neoaplectana bibionis could be cultured with the ... | 1983 | 6832284 |
| different dna-binding proteins in the primary and secondary forms of xenorhabdus luminescens. | basic, heat-stable proteins binding to double-stranded dna (hasp) were isolated from the primary and secondary forms of xenorhabdus luminescens and their composition compared. two of the proteins with low molecular weight are present in both the primary and secondary forms, whereas two others are present only in the latter. the described protein fractions may be involved in the regulation of transitions between the two forms of x. luminescens. | 1993 | 7504870 |
| inability of the polyphasic approach to systematics to determine the relatedness of the genera xenorhabdus and photorhabdus. | comparative analysis of the genes coding for 16s rrna of the type strains of xenorhabdus and photorhabdus species indicates the close phylogenetic relationship of these two genera. however, distance matrix analyses do not unambiguously separate the symbionts of entomopathogenic nematodes according to their assignment into different genera. when various 16s rrna gene sequences from a selection of members of the gamma subclass of proteobacteria and outgroup taxa were used, the intrageneric relatio ... | 1995 | 7537072 |
| tryptophan 250 on the alpha subunit plays an important role in flavin and aldehyde binding to bacterial luciferase. effects of w-->y mutations on catalytic function. | bacterial luciferase is a heterodimer (alpha beta) that catalyzes the oxidation of fmnh2 and a fatty aldehyde, resulting in light emission. to explore the nature of the flavin binding site with respect to the role of tryptophan residues, the catalytic and binding properties of single-point mutants of xenorhabdus luminescens luciferase with one of the eight tryptophans converted to a tyrosine residue were investigated by luminescence and fluorescence measurements. conversion of tryptophans 194 an ... | 1995 | 7578121 |
| susceptibility of suspended and surface-attached salmonella enteritidis to biocides and elevated temperatures. | the differential resistance of substratum-attached, detached, and planktonic cells of salmonella enteritidis phage type 4 was studied by using several inimical processes and in vivo bioluminescence as a nondestructive, real-time reporter of metabolic activity. bioluminescence in this strain was mediated by a construction containing the entire lux operon from photorhabdus luminescens. an excellent correlation between bioluminescence and classical plate count data was obtained when we compared att ... | 1995 | 7646010 |
| formation of active bacterial luciferase between interspecific subunits in vivo. | interspecific complementation between luxas and luxbs from vibrio harveyi, vibrio fischeri, photobacterium leiognathi and xenorhabdus luminescens was examined in vivo. the individual genes from these species were cloned on different compatible plasmids or amplified by pcr and brought together to yield cis combinations without extraneous dna. the beta subunits from v. harveyi and x. luminescens form active enzyme only with alpha subunits from one of these species. all other combinations yield act ... | 1995 | 7676858 |
| expression of luxcd-e in anabaena sp. can replace the use of exogenous aldehyde for in vivo localization of transcription by luxab. | the genes luxcdabe from four luminescent bacteria suffice for light production in escherichia coli [meighen, microbiol. rev. 55 (1991) 123-142]. we have inserted these gene clusters between inverted polylinkers, and placed the resulting cassettes as reporters within derivatives of transposon tn5. anabaena sp. strain pcc 7120 was mutagenized with these transposons. the luminescence of all but the most highly self-luminescent resulting derivatives of anabaena sp. was strongly dependent on exogenou ... | 1994 | 7959046 |
| immobilization of escherichia coli expressing the lux genes of xenorhabdus luminescens. | the luxcdabe operon of xenorhabdus luminescens was cloned into puc18 to make plite27. expression of the lux genes from the lac promoter resulted in strong constitutive light emission by escherichia coli dh5 carrying the recombinant lux plasmid, plite27. when strain dh5(plite27) was immobilized with sodium alginate-cacl2, the embedded cells retained their luminescence up to 2 weeks under appropriate storage conditions. | 1994 | 7986053 |
| identification of the genes encoding nad(p)h-flavin oxidoreductases that are similar in sequence to escherichia coli fre in four species of luminous bacteria: photorhabdus luminescens, vibrio fischeri, vibrio harveyi, and vibrio orientalis. | genes encoding nad(p)h-flavin oxidoreductases (flavin reductases) similar in both size and sequence to fre, the most abundant flavin reductase in escherichia coli, were identified in four species of luminous bacteria, photorhabdus luminescens (atcc 29999), vibrio fischeri (atcc 7744), vibrio harveyi (atcc 33843), and vibrio orientalis (atcc 33934). nucleotide sequence analysis showed fre-like flavin reductases in p. luminescens and v. fischeri to consist of 233 and 236 amino acids, respectively. ... | 1994 | 8206831 |
| subunit interactions and the role of the luxa polypeptide in controlling thermal stability and catalytic properties in recombinant luciferase hybrids. | bacterial luciferases with over 70% sequence identity from the terrestrial species, xenorhabdus luminescens, and the marine species, vibrio harveyi, exhibit large differences in thermal stability (szittner and meighen, 1990, j. biol. chem. 265, 16581-16587). the origin of these differences was investigated with genetically constructed hybrids containing one subunit from x. luminescens and the other from v. harveyi. while no activity was detected with the single (alpha and beta) subunits both in ... | 1993 | 8399314 |
| heterologous gene expression in campylobacter coli: the use of bacterial luciferase in a promoter probe vector. | a novel promoter probe plasmid (psp73) was constructed to allow the analysis of environmentally regulated gene expression in campylobacter. the vector utilizes the luxab genes from xenorhabdus luminescens, which encode a thermostable luciferase, as reporters of gene expression. the utility of this reporter system was demonstrated by placing the expression of luxab under the transcriptional control of the flaa gene promoter. | 1993 | 8405932 |
| phase variation in xenorhabdus luminescens: cloning and sequencing of the lipase gene and analysis of its expression in primary and secondary phases of the bacterium. | the phenomenon of phase variation in the insect-pathogenic bacterium xenorhabdus luminescens was investigated. differential activity of the lipase enzyme (ec 3.1.1.3) was observed between the two phases of the bacteria. the enzyme was found to be secreted into the culture medium, and about five to six times greater specific activity was secreted by the primary phase than by the secondary form. the lipase gene (lip-1) was cloned and sequenced. the data imply that there is only a single tween 80-u ... | 1993 | 8449874 |
| sequence of the luxd gene encoding acyltransferase of the lux operon from photobacterium leiognathi. | the nucleotide sequence of luxd (embl accession no. x65611), encoding acyltransferase (act), of the lux operon from photobacterium leiognathi pl741 was determined, and the amino acid (aa) sequence was deduced. act is a component of the fatty acid reductase complex, which is responsible for converting fatty acid to aldehyde that serves as the substrate in the luciferase-catalyzed bioluminescent reactions. the protein has a calculated m(r) of 34,384 and comprises 305 aa residues. alignment and com ... | 1993 | 8472957 |
| construction and characterization of hybrid luciferases coded by lux genes from xenorhabdus luminescens and vibrio fischeri. | molecular cloning techniques were employed to obtain hybrid luciferases with their alpha and beta subunits encoded by luxa and luxb genes, respectively, from xenorhabdus luminescens strain hw or vibrio fischeri. although the two wild-type luminous bacteria are phylogenetically diverged, the hybrid luciferase xf comprising an alpha from x. luminescens hw and a beta from v. fischeri and the hybrid luciferase vi comprising an alpha from v. fischeri and a beta from x. luminescens hw were both functi ... | 1993 | 8506400 |
| identification of two pigments and a hydroxystilbene antibiotic from photorhabdus luminescens. | two yellow pigments were isolated for the first time from the entomopathogenic bacterium photorhabdus luminescens in liquid culture and were identified as the anthraquinone derivatives 3,8-dimethoxy-1-hydroxy-9,10-anthraquinone (minor) and 1,3-dimethoxy-8-hydroxy-9,10-anthraquinone (major). a known antibiotic, 3,5-dihydroxy-4-isopropylstilbene, was also detected and for the first time showed strong fungicidal activity against several fungi of medical and agricultural importance. | 1995 | 8534100 |
| chitinase activity of xenorhabdus and photorhabdus species, bacterial associates of entomopathogenic nematodes. | xenorhabdus nematophilus (three strains), xenorhabdus bovienii (one strain), and photorhabdus luminescens (one strain) showed both exo- and endochitinase activity using p-nitrophenyl-n-acetyl-beta-d-glucosaminide and p-nitrophenyl-beta-d-n,n',n'-triacetylchitotriose, respectively, as substrates. one to three bands were detected on page gel with glycol chitin after electrophoresis. variation in exo- and endochitinase activity among different species and strains was detected with the strongest act ... | 1996 | 8858906 |
| nucleotide sequence and functional analysis of the luxe gene encoding acyl-protein synthetase of the lux operon from photobacterium leiognathi. | nucleotide sequence of the luxe gene genbank accession no. u66407 from photobacterium leiognathi pl741 has been determined, and the amino acid sequence of acyl-protein synthetase encoded by the luxe gene is deduced. nucleotide sequence reveals that the luxe gene encodes acyl-protein synthetase, which is a component of the fatty acid reductase complex that is responsible for converting fatty acid to aldehyde as substrate in the luciferase-catalyzed bioluminescence reaction. the acyl-protein synth ... | 1996 | 8941351 |
| fast and accurate identification of xenorhabdus and photorhabdus species by restriction analysis of pcr-amplified 16s rrna genes. | thirteen bacterial strains of xenorhabdus and 14 strains of photorhabdus originating from a wide range of geographical and nematode host sources were typed by analyzing 16s rrna gene (rdna) restriction patterns obtained after digestion of pcr-amplified 16s rdnas. eight tetrameric restriction endonucleases were examined. a total of 17 genotypes were identified, forming two heterogeneous main clusters after analysis by the unweighted pair-group method using arithmetic averages: group i included al ... | 1997 | 9023937 |
| phylogenetic evidence for the taxonomic heterogeneity of photorhabdus luminescens. | the sequences of the 16s rrna gene of 40 strains of bacterial symbionts isolated from the nematodes heterorhabditis spp. and seven bacterial symbionts of the nematodes steinernema spp. which were isolated from different geographical areas, as well as the type strain of xenorhabdus japonicus, were determined and compared to each other and to the sequences of several reference strains of members of the enterobacteriaceae. the data confirmed the separate status of the two genera of symbionts of ent ... | 1997 | 9103628 |
| the construction and application of a lux-based nitrate biosensor. | a plasmid-borne transcriptional fusion between the escherichia coli nitrate reductase (narg) promoter and the photorhabdus luminescens lux operon provides e. coli with a highly bioluminescent phenotype in the presence of nitrate. this e. coli biosensor can detect nitrate to a level of 5 x 10(-5) mol l-1 (0.3 ppm), levels relevant to those levels encountered in brewing water. since induction of the narg promoter requires narl, the plasmid-based sensor can also be used to interrogate enteric bacte ... | 1997 | 9172442 |
| analysis of proteins from different phase variants of the entomopathogenic bacteria photorhabdus luminescens by two-dimensional zymography. | two-dimensional zymography which combines two-dimensional electrophoresis with zymography was used to analyze proteases and other proteins produced by different phase variants of two strains of photorhabdus luminescens. both the primary and secondary phases of p. luminescens strains hp and hm secreted proteases. the protease in p. luminescens hp has a molecular weight (mr) of 57,000 and an isoelectric point (pi) of 4.4 whereas that in p. luminescens hm has an mr of 59,000 and pi of 4.9. several ... | 1997 | 9194616 |
| structure of cell envelope components of the primary and secondary forms of xenorhabdus luminescens. | muropeptide analysis of muramidase-digested murein (peptidoglycan) did not reveal any differences between the primary and secondary forms of xenorhabdus luminescens. similarly, no significant differences were found in the overall protein composition of the cytoplasmic and outer membranes of both forms. | 1997 | 9271844 |
| h-ns protein represses transcription of the lux systems of vibrio fischeri and other luminous bacteria cloned into escherichia coli. | high expression in escherichia coli of the lux system cistron of a luminous bacteria under its own control has been accomplished only for the vibrio fischeri lux system at high cell density. mutation of the hns gene in e. coli has resulted in strong expression of the v. fischeri lux system at low cell density even in an rpos-deleted strain of e. coli that emits very low levels of luminescence. the e. coli double mutant, mc4110 hns::kan rpos::tet carrying the lux system of v. fischeri, developed ... | 1997 | 9353217 |
| quantitative analysis of a bacteria-derived antibiotic in nematode-infected insects using hplc-uv and tlc-uv methods. | 3,5-dihydroxy-4-isopropylstilbene (st), an antibiotic produced by the bacterial symbiont photorhabdus luminescens of the nematodes of the genus heterorhabditis was determined quantitatively in nematode bacterium-infected insects using hplc or tlc for separation and uv for quantification. comparable and reproducible results were obtained with both hplc-uv and tlc-uv methods. several factors, including solvents for extraction of the antibiotic from the infected insects, eluents for tlc development ... | 1997 | 9448074 |
| constricted flux through the branched-chain amino acid biosynthetic enzyme acetolactate synthase triggers elevated expression of genes regulated by rpos and internal acidification. | the first common enzyme of isoleucine and valine biosynthesis, acetolactate synthase (als), is specifically inhibited by the herbicide sulfometuron methyl (sm). to further understand the physiological consequences of flux alterations at this point in metabolism, escherichia coli genes whose expression was induced by partial inhibition of als were sought. plasmid-based fusions of random e. coli dna fragments to photorhabdus luminescens luxcdabe were screened for bioluminescent increases in active ... | 1998 | 9473030 |
| insertional inactivation of genes encoding the crystalline inclusion proteins of photorhabdus luminescens results in mutants with pleiotropic phenotypes. | the entomopathogenic bacterium photorhabdus luminescens exhibits phase variation when cultured in vitro. the variant forms of p. luminescens are pleiotropic and are designated phase i and phase ii variants. one of the characteristic phenotypes of phase i cells is the production of two types of intracellular protein inclusions. the genes encoding the protein monomers that form these inclusions, designated cipa and cipb, were cloned and characterized. cipa and cipb encode hydrophobic proteins of 1 ... | 1998 | 9495767 |
| bioluminescence as a reporter of intracellular survival of bordetella bronchiseptica in murine phagocytes. | the uptake and persistence of bordetella bronchiseptica was characterized in murine phagocytes by using a novel bioluminescence-based reporter system. a mini-tn5 promoter probe carrying the intact lux operon from the terrestrial bacterium photorhabdus luminescens which allowed measurement of light output without the addition of exogenous substrate was constructed. it was used to create a pool of bioluminescent fusion strains of b. bronchiseptica. the internalization and persistence in murine mac ... | 1998 | 9632586 |
| insecticidal toxins from the bacterium photorhabdus luminescens. | transgenic plants expressing bacillus thuringiensis (bt) toxins are currently being deployed for insect control. in response to concerns about bt resistance, we investigated a toxin secreted by a different bacterium photorhabdus luminescens, which lives in the gut of entomophagous nematodes. in insects infected by the nematode, the bacteria are released into the insect hemocoel; the insect dies and the nematodes and bacteria replicate in the cadaver. the toxin consists of a series of four native ... | 1998 | 9641921 |
| the apee gene of salmonella typhimurium encodes an outer membrane esterase not present in escherichia coli. | salmonella typhimurium aper mutations lead to overproduction of an outer membrane-associated n-acetyl phenylalanine beta-naphthyl ester-cleaving esterase that is encoded by the apee gene (p. collin-osdoby and c. g. miller, mol. gen. genet. 243:674-680, 1994). this paper reports the cloning and nucleotide sequencing of the s. typhimurium apee gene as well as some properties of the esterase that it encodes. the predicted product of apee is a 69.9-kda protein which is processed to a 67-kda species ... | 1998 | 9657991 |
| engineering the luxcdabe genes from photorhabdus luminescens to provide a bioluminescent reporter for constitutive and promoter probe plasmids and mini-tn5 constructs. | the luxcdabe operon of photorhabdus luminescens has been cloned and engineered as an easily mobilisable cassette flanked by sites for commonly used restriction enzymes. constitutive and promoter probe plasmids utilising the p. luminescens luxcdabe have been constructed using a number of compatible replicons and antibiotic markers. complementary to these plasmids, a range of promoterless and constitutive luxcdabe mini-tn5 derivatives has been constructed. the potential of coupling mini-tn5 luxcda ... | 1998 | 9673022 |
| photorhabdus luminescens luxcdabe promoter probe vectors. | | 1998 | 9680611 |
| purification and characterization of a high-molecular-weight insecticidal protein complex produced by the entomopathogenic bacterium photorhabdus luminescens | photorhabdus luminescens is a gram-negative enteric bacterium that is found in association with entomopathogenic nematodes of the family heterorhabditidae. the nematodes infect a variety of soil-dwelling insects. upon entering an insect host, the nematode releases p. luminescens cells from its intestinal tract, and the bacteria quickly establish a lethal septicemia. when grown in peptone broth, in the absence of the nematodes, the bacteria produce a protein toxin complex that is lethal when fed ... | 1998 | 9687469 |
| a novel insecticidal toxin from photorhabdus luminescens, toxin complex a (tca), and its histopathological effects on the midgut of manduca sexta | photorhabdus luminescens is a bacterium which is mutualistic with entomophagous nematodes and which secretes high-molecular-weight toxin complexes following its release into the insect hemocoel upon nematode invasion. thus, unlike other protein toxins from bacillus thuringiensis (delta-endotoxins and vip's), p. luminescens toxin (pht) normally acts from within the insect hemocoel. unexpectedly, therefore, the toxin complex has both oral and injectable activities against a wide range of insects. ... | 1998 | 9687470 |
| in vitro and in vivo characterization of a small-colony variant of the primary form of photorhabdus luminescens md (enterobacteriaceae) | a small-colony variant (vsm) of the primary form (vp) of photorhabdus luminescens md from in vitro and in vivo cultures is described. unlike the primary form, vp, the vsm variant is not the preferred diet of its nematode symbiont, a heterorhabditis sp., does not support development and reproduction of the nematode, and is less pathogenic than vp to galleria mellonella larvae. vsm cells were carried by 25% of infective juveniles, but they comprised a very low percentage ( approximately 0.4%) of t ... | 1998 | 9726862 |
| active resistance of entomophagous rhabditid heterorhabditis bacteriophora to insect immunity. | a specific extracellular proteinase, degrading selectively the cecropin-based defence system of insects, is secreted into the larval body during parasitism of the greater wax moth by the heterorhabditis bacteriophora/photorhabdus luminescens complex and by phase 1 of p. luminescens. the proteolytic digestion of insect inducible cecropin-like immune molecules was demonstrated by the disappearance of the galleria mellonella cecropins and purified hyalophora cecropin b peptide page bands upon expos ... | 1998 | 9774783 |
| a recombinant escherichia coli sensor strain for the detection of tetracyclines. | a bioluminescent escherichia coli k-12 strain for the specific detection of the tetracycline group of antibiotics is described. a sensor plasmid, containing five genes from bacterial luciferase operon of photorhabdus luminescens inserted under the control of tetracycline-responsive elements of the transposon tn10, was constructed. usage of the full-length luciferase operon in the sensor resulted in tetracycline-dependent light production without additions, i.e., self-luminescent phenotype, since ... | 1998 | 9823708 |
| molecular identification of photorhabdus luminescens strains by amplification of specific fragments of the 16s ribosomal dna. | sequence variation within the variable region of the 16s rrna at position 440 to 480 allowed the synthesis of specific pcr primers for the identification of groups within the species photorhabdus luminescens, symbionts of entomopathogenic nematodes of the genus heterorhabditis. for the second pcr primer the highly conserved region at 755 to 795 was used. the p. luminescens type strain specific primer could not recognize any other p. luminescens strain. the primer temperatus based on the sequence ... | 1998 | 9924819 |
| successful parasitation of locusts by entomopathogenic nematodes is correlated with inhibition of insect phagocytes. | the entomopathogenic nematodes heterorhabditis megidis and steinernema feltiae turned out to be successful antagonists of the orthopteran insects locusta migratoria and schistocerca gregaria. the death rate of locusts maintained on nematode-inoculated sand was remarkably high. even dosages as low as one nematode per cubic centimeter of sand killed approximately 50% of the locusts within 10 days. the impact of parasitation on locusts' immune defense was closely investigated for l. migratoria para ... | 1999 | 10066395 |
| photorhabdus luminescens w-14 insecticidal activity consists of at least two similar but distinct proteins. purification and characterization of toxin a and toxin b. | both the bacterium photorhabdus luminescens alone and its symbiotic photorhabdus-nematode complex are known to be highly pathogenic to insects. the nature of the insecticidal activity of photorhabdus bacteria was investigated for its potential application as an insect control agent. it was found that in the fermentation broth of p. luminescens strain w-14, at least two proteins, toxin a and toxin b, independently contributed to the oral insecticidal activity against southern corn rootworm. purif ... | 1999 | 10092674 |
| folding and refolding of thermolabile and thermostable bacterial luciferases: the role of dnakj heat-shock proteins. | bacterial luciferases are highly suitable test substrates for the analysis of refolding of misfolded proteins, as they are structurally labile and loose activity at 42 degrees c. heat-denatured thermolabile vibrio fischeri luciferase and thermostable photorhabdus luminescens luciferase were used as substrates. we found that their reactivation requires the activity of the dnak chaperone system. the dnakj chaperones were dispensable in vivo for de novo folding at 30 degrees c of the luciferase, bu ... | 1999 | 10218489 |
| antimicrobial properties and morphological characteristics of two photorhabdus luminescens strains. | the biological properties of two photorhabdus luminescens isolates (mu1 and mu2) of environmental source and the activity of antimicrobial agar diffusible agents (aada) produced by the same are reported. with regard to cultural features, two variant forms for p. luminescens mu1 and three for p. luminescens mu2 (including an intermediate phase i-like form) have been found. these three forms differ in biological and biochemical properties: beta-lactamase, urease, bioluminescence and antimicrobial ... | 1999 | 10322611 |
| stimulation of no synthase activity in the immune-competent lepidopteran estigmene acraea hemocyte line. | in contrast to the vertebrate immune system, nearly nothing is known about the immunological role of nitric oxide (no) in invertebrates. this study provides evidence of the presence of a no synthase (nos) activity in an immune-competent, macrophage-like insect hemocyte line, previously established from larvae of the lepidopteran insect estigmene acraea. as proven by photometric determination of nitroblue tetrazolium reduction after cell fixation, the e. acraea cells possess nadph diaphorase (nad ... | 1999 | 10369182 |
| photorhabdus toxins: novel biological insecticides. | following concerns over the potential for insect resistance to insecticidal bacillus thuringiensis toxins expressed in transgenic plants, there has been recent interest in novel biological insecticides. over the past year there has been considerable progress in the cloning of several alternative toxin genes from the bacteria photorhabdus luminescens and xenorhabdus nematophilus. these genes encode large insecticidal toxin complexes with little homology to other known toxins. | 1999 | 10383860 |
| survival of insect pathogenic and human clinical isolates of photorhabdus luminescens in previously sterile soil. | most characterized strains of the bacterium photorhabdus luminescens are symbionts of entomopathogenic nematodes, whereas other strains have been isolated from human clinical specimens. the ability of p. luminescens strains to survive and grow in soil has received limited attention, with some studies indicating these bacteria have little or no ability to persist in soil. survival and (or) growth of p. luminescens strains in previously sterilized soil, and examination of different soil amendments ... | 1999 | 10408101 |
| spectral properties of trp182, trp194, and trp250 on the alpha subunit of bacterial luciferase. | the phosphorescence and fluorescence properties of bacterial luciferase (alphabeta) mutants from xenorhabdus luminescens were investigated. all tryptophans in the alpha and beta subunits were replaced with tyrosines except for one or two tryptophans in the alpha subunit. because one luciferase mutant (w250) retained only a single tryptophan in the alpha subunit while two other mutants (w182/250 and w194/250) each contained two tryptophans in the alpha subunit, it was possible to deduce the spect ... | 1999 | 10512764 |
| isolation, identification, and molecular characterization of strains of photorhabdus luminescens from infected humans in australia. | we describe the isolation of photorhabdus (xenorhabdus) luminescens from four australian patients: two with multiple skin lesions, one with bacteremia only, and one with disseminated infection. one of the patients had multiple skin lesions following the bite of a spider, while the lesions in the other patient were possibly associated with a spider bite. the source of infection for the remaining two patients is unknown. as a member of the family enterobacteriaceae, p. luminescens is unusual in th ... | 1999 | 10523568 |
| control of luminescence decay and flavin binding by the luxa carboxyl-terminal regions in chimeric bacterial luciferases. | bacterial luciferases (luxab) can be readily classed as slow or fast decay luciferases based on their rates of luminescence decay in a single turnover assay. luciferases from vibrio harveyi and xenorhabdus (photorhabdus) luminescens have slow decay rates, and those from the photobacterium genus, such as p. (vibrio) fischeri, p. phosphoreum, and p. leiognathi, have rapid decay rates. by generation of an x. luminescens-based chimeric luciferase with a 67 amino acid substitution from p. phosphoreum ... | 1999 | 10529227 |
| polyphasic classification of the genus photorhabdus and proposal of new taxa: p. luminescens subsp. luminescens subsp. nov., p. luminescens subsp. akhurstii subsp. nov., p. luminescens subsp. laumondii subsp. nov., p. temperata sp. nov., p. temperata subsp. temperata subsp. nov. and p. asymbiotica sp. nov. | the taxonomic position of photorhabdus strains was examined through the results of dna relatedness (s1 nuclease method) studies associated with the determination of delta tm, 16s rrna phylogenetic inferences and phenotypic characterization, including morphological, auxanographic, biochemical and physiological properties. three genomic species were delineated on a consensus assessment. one of these species corresponded to photorhabdus luminescens, since strains were at least 50% related to the ty ... | 1999 | 10555346 |
| pathogenicity, development, and reproduction of heterorhabditis bacteriophora and steinernema carpocapsae under axenic in vivo conditions. | galleria mellonella larvae cultured axenically were treated with axenic dauer juveniles of heterorhabditis bacteriophora and steinernema carpocapsae. after 3 days s. carpocapsae had killed all insects, with 9.4 +/- 4.3 nematodes per larva. h. bacteriophora were unable to kill g. mellonella, although 13.3 +/- 6.4 nematodes per galleria were found in the hemocoel. invading nematodes of both strains recovered from the dauer stage. h. bacteriophora developed into hermaphrodites with eggs and j1 in t ... | 2000 | 10631058 |
| secreted proteases from photorhabdus luminescens: separation of the extracellular proteases from the insecticidal tc toxin complexes. | photorhabdus luminescens secretes both high molecular weight insecticidal toxin complexes and also a range of extracellular proteases into culture broth. previous studies by others have suggested that insecticidal activity of the broth is associated with these proteases. however, by gene cloning and targeted knock-out, we have previously shown that oral insecticidal activity is associated with high molecular weight 'toxin complexes' (tc) encoded by toxin complex or tc genes. here we further clar ... | 2000 | 10646972 |
| deficiency of current methods in assaying endochitinase activity. | since chitin is degraded by a combination of both endo- and exochitinases, it is likely that both enzymes will be present in a crude extract. currently used substrates for detecting endochitinase activity suffer from the fact that they could easily be digested by the contaminating exochitinase, thus giving either a false-positive or an inaccurate reading of the endochitinase activity. using photorhabdus luminescens, a bacterium symbiotically associated with insect-parasitic nematode heterorhabdi ... | 2000 | 10679198 |
| occurrence of natural dixenic associations between the symbiont photorhabdus luminescens and bacteria related to ochrobactrum spp. in tropical entomopathogenic heterorhabditis spp. (nematoda, rhabditida). | bacteria naturally associated with the symbiont photorhabdus luminescens subsp. akhurstii were isolated from the entomopathogenic nematode heterorhabditis indica. bacterial isolates distinct from p. luminescens subsp. akhurstii were obtained from 33% of the samples. fourteen bacterial isolates, from nematodes collected from three different caribbean islands, were characterized by conventional phenotypic tests, restriction fragment length polymorphism and sequence analyses of pcr-amplified 16s rr ... | 2000 | 10746775 |
| improved bacterial sos promoter:lux fusions for genotoxicity detection. | escherichia coli strains containing plasmid-borne fusions of vibrio fischeri lux to the reca promoter-operator region were previously shown to be potentially useful for detecting genotoxicants. in an attempt to improve past performance, the present study examines several modifications and variations of this design, singly or in various combinations: (1) modifying the host cell's toxicant efflux capacity via a tolc mutation; (2) incorporating the lux fusion onto the bacterial chromosome, rather t ... | 2000 | 10751731 |
| [cloning and expression of the lux-operon of photorhabdus luminescens, strain zm1: nucleotide sequence of luxab genes and basic properties of luciferase]. | a chromosomal fragment of bacteria photorhabdus luminescence zm1, which contains the lux operon, was cloned into the vector puc18. the hybrid clone containing plasmid pxen7 with the ecori fragment approximately 7-kb was shown to manifest a high level of bioluminescence. by subcloning and restriction analysis of the ecori fragment, the location of luxcdabe genes relative to restriction sites was determined. the nucleotide sequence of the dna fragment containing the luxa and luxb genes encoding al ... | 2000 | 10779906 |
| a streptavidin-luciferase fusion protein: comparisons and applications. | luciferases are unique enzymes in being capable of emitting visible light as one of the end-products of their catalysis. both procaryotic and eucaryotic organisms exist that emit light, and the luciferases from these organisms differ considerably in size as well as chemistry of catalysis. two main, i.e. most studied groups, are the bacterial luciferases of e.g. vibrio fisheri, vibrio harveyi, and photorhabdus luminescens, responding to fmnh2, long-chain aldehyde and molecular oxygen and the inse ... | 1999 | 10796991 |
| monitoring bioluminescent staphylococcus aureus infections in living mice using a novel luxabcde construct. | strains of staphylococcus aureus were transformed with plasmid dna containing a photorhabdus luminescens lux operon (luxabcde) that was genetically modified to be functional in both gram-positive and gram-negative bacteria. s. aureus cells containing this novel lux construct, downstream of an appropriate promoter sequence, are highly bioluminescent, allowing the detection of fewer than 100 cfu in vitro (direct detection of exponentially dividing cells in liquid culture). furthermore, these bacte ... | 2000 | 10816517 |
| novel insecticidal toxins from nematode-symbiotic bacteria. | the current strategy of using transgenic crops expressing insecticidal protein toxins is placing increasing emphasis on the discovery of novel toxins, beyond those already derived from the bacterium bacillus thuringiensis. here we review the cloning of four insecticidal toxin complex (tc) encoding genes from a different bacterium photorhabdus luminescens and of similar gene sequences from xenorhabdus nematophilus. both these bacteria occupy the gut of entomopathogenic nematodes and are released ... | 2000 | 10892346 |
| ecotoxicological testing with new kinetic photorhabdus luminescens growth and luminescence inhibition assays in microtitration scale | miniaturized luminescence and growth inhibition assays in microtitration plates with the terrestric enthomopathogenic nematode symbiont photorhabdus luminescens (dsmz 3368t) are presented and compared with standardized tests with vibrio fischeri (dsmz 7151/nrrlb-11177) and pseudomonas putida (dsmz 50026). toxicological parameters (ec and g values) of selected reference toxicants (e.g. heavy metals and environmental samples) were obtained at different temperatures and without sodium chloride supp ... | 1999 | 10903092 |
| a genomic sample sequence of the entomopathogenic bacterium photorhabdus luminescens w14: potential implications for virulence. | photorhabdus luminescens is a pathogenic bacterium that lives in the guts of insect-pathogenic nematodes. after invasion of an insect host by a nematode, bacteria are released from the nematode gut and help kill the insect, in which both the bacteria and the nematodes subsequently replicate. however, the bacterial virulence factors associated with this "symbiosis of pathogens" remain largely obscure. in order to identify genes encoding potential virulence factors, we performed approximately 2,00 ... | 2000 | 10919786 |
| antibiotic production in relation to bacterial growth and nematode development in photorhabdus--heterorhabditis infected galleria mellonella larvae. | the population of photorhabdus luminescens c9, bacterial symbiont of the entomopathogenic nematode, heterorhabditis megidis 90, increased rapidly to 1.2-2.6x10(9) cells g(-1) wet galleria mellonella larvae within 24 h of nematode infection of the larvae, and maintained a relatively constant level (1.2-2.0x10(10) cells g(-1)) through the entire 14-day period of nematode development. the antibiotic, 3, 5-dihydroxy-4-isopropylstilbene, was produced by p. luminescens c9 after 24 h of nematode infect ... | 2000 | 10930742 |
| influence of the aeration rate on the yields of the biocontrol nematode heterorhabditis megidis in monoxenic liquid cultures. | the entomopathogenic nematode-bacterium complex heterorhabditis megidis photorhabdus luminescens was cultured in 10-1 internal loop bioreactors with marine impellers at aeration rates of 0.3 vvm and 0.7 vvm. process parameters like impeller velocity and oxygen saturation were controlled at equal set points. the bacterial density was assessed at 24 h. nematode dauer juveniles (dj) were then inoculated and the development to adults after 8 days and final dj yields after 16 days were recorded. the ... | 2000 | 10951998 |
| a group-specific microbiological test for the detection of tetracycline residues in raw milk. | the potentiality of using a luminescent escherichia coli strain for the specific detection of tetracycline residues in raw bovine milk was investigated. the sensor cells contain a reporter plasmid carrying the bacterial luciferase operon of photorhabdus luminescens under the control of the tetracycline responsive control region from transposon tn10. incubation of the cells with the sample containing tetracyclines increases the light emission of the sensor cells. the most sensitive tetracycline d ... | 2000 | 10956118 |
| plasmid-located pathogenicity determinants of serratia entomophila, the causal agent of amber disease of grass grub, show similarity to the insecticidal toxins of photorhabdus luminescens. | serratia entomophila and serratia proteamaculans cause amber disease in the grass grub costelytra zealandica (coleoptera: scarabaeidae), an important pasture pest in new zealand. larval disease symptoms include cessation of feeding, clearance of the gut, amber coloration, and eventual death. a 115-kb plasmid, padap, identified in s. entomophila is required for disease causation and, when introduced into escherichia coli, enables that organism to cause amber disease. a 23-kb fragment of padap tha ... | 2000 | 10960097 |
| the predicted structure of photopexin from photorhabdus shows the first haemopexin-like motif in prokaryotes. | the insect pathogenic bacterium photorhabdus luminescens secretes several insecticidal high molecular mass 'toxin complexes'. analysis of the putative pathogenicity island surrounding the toxin complex a (tca) locus revealed two open reading frames (orfs) of unknown function. the predicted protein sequences of these orfs show a repeated motif similar to those found in the vertebrate haem scavenging molecule haemopexin, limunectin (a phosphocholine binding protein from limulus) and the c-terminal ... | 2000 | 11004411 |
| growth of photorhabdus luminescens in batch and glucose fed-batch culture. | photorhabdus luminescens, a bacterial symbiont of entomopathogenic biocontrol nematodes, was grown in batch and glucose fed-batch culture. the cell density, bioluminescence, production of antibiotic substances, number of cells with inclusion bodies, glucose concentration and oxygen uptake rate were recorded. the addition of 12.4 g 1(-1) glucose prolonged the growth, and the yield almost doubled, from 6.85 g 1(-1) to 12.45 g 1(-1) dry mass. the production of antibiotic substances increased by 140 ... | 2000 | 11030567 |
| detection of tetracyclines with luminescent bacterial strains. | the performance of two bioluminescent escherichia coli k-12 strains for the specific detection of the tetracycline family of antimicrobial agents was compared, and the analytical applicability of one of the strains was preliminarily evaluated. one sensor plasmid contained the bacterial luciferase operon of photorhabdus luminescens under the control of the tetracycline-responsive element from transposon tn10 (15). an analogous plasmid construction with firefly (photinus pyralis) luciferase report ... | 2000 | 11038486 |
| a new broad-spectrum protease inhibitor from the entomopathogenic bacterium photorhabdus luminescens. | a new protease inhibitor was purified to apparent homogeneity from a culture medium of photorhabdus luminescens by ammonium sulfate precipitation and preparative isoelectric focusing followed by affinity chromatography. ph. luminescens, a bacterium symbiotically associated with the insect-parasitic nematode heterorhabditis bacteriophora, exists in two morphologically distinguishable phases (primary and secondary). it appears that only the secondary-phase bacterium produces this protease inhibito ... | 2000 | 11101672 |
| validation of a noninvasive, real-time imaging technology using bioluminescent escherichia coli in the neutropenic mouse thigh model of infection. | a noninvasive, real-time detection technology was validated for qualitative and quantitative antimicrobial treatment applications. the lux gene cluster of photorhabdus luminescens was introduced into an escherichia coli clinical isolate, ec14, on a multicopy plasmid. this bioluminescent reporter bacterium was used to study antimicrobial effects in vitro and in vivo, using the neutropenic-mouse thigh model of infection. bioluminescence was monitored and measured in vitro and in vivo with an inten ... | 2001 | 11120955 |
| liquid media development for heterorhabditis bacteriophora: lipid source and concentration. | lipids are important entomopathogenic nematode nutritional components because they are energy reserves and serve as indicators of nematode quality. the composition and concentration of the media lipid component determine bacterial and nematode yields. heterorhabditis bacteriophora and its symbiont, photorhabdus luminescens, were cultured in media containing various lipid sources. as lipid concentration increased from 2.5% to 8.0% (w/v), the final yield and productivity [calculated from the numbe ... | 2000 | 11152066 |
| microbial sensors of ultraviolet radiation based on reca'::lux fusions. | escherichia coli strains containing plasmid-borne fusions of the reca promoter-operator region to the vibrio fischeri lux genes were previously shown to increase their luminescence in the presence of dna damage hazards, and thus to be useful for genotoxicant detection. the present study expands previous work by demonstrating and investigating the luminescent response of these strains to ultraviolet radiation. several genetic variants of the basic reca'::lux design were examined, including a tolc ... | 2000 | 11209459 |
| a genomic approach to gene fusion technology. | gene expression profiling provides powerful analyses of transcriptional responses to cellular perturbation. in contrast to dna array-based methods, reporter gene technology has been underused for this application. here we describe a genomewide, genome-registered collection of escherichia coli bioluminescent reporter gene fusions. dna sequences from plasmid-borne, random fusions of e. coli chromosomal dna to a photorhabdus luminescens luxcdabe reporter allowed precise mapping of each fusion. the ... | 2001 | 11226277 |
| the tc genes of photorhabdus: a growing family. | the toxin complex (tc) genes of photorhabdus encode insecticidal, high molecular weight tc toxins. these toxins have been suggested as useful alternatives to those derived from bacillus thuringiensis for expression in insect-resistant transgenic plants. although photorhabdus luminescens is symbiotic with nematodes that kill insects, tc genes have recently been described from other insect-associated bacteria such as serratia entomophila, an insect pathogen, and yersinia pestis, the causative agen ... | 2001 | 11286884 |
| effect of photorhabdus luminescens phase variants on the in vivo and in vitro development and reproduction of the entomopathogenic nematodes heterorhabditis bacteriophora and steinernema carpocapsae. | photorhabdus luminescens (enterobacteriaceae) is a symbiont of entomopathogenic nematodes heterorhabditis spp. (nematoda: rhabditida) used for biological control of insect pests. for industrial mass production, the nematodes are produced in liquid media, pre-incubated with their bacterial symbiont, which provides nutrients essential for the nematode's development and reproduction. particularly under in vitro conditions, p. luminescens produces phase variants, which do not allow normal nematode d ... | 2001 | 11311434 |
| sequence analysis of insecticidal genes from xenorhabdus nematophilus pmfi296. | three strains of xenorhabdus nematophilus showed insecticidal activity when fed to pieris brassicae (cabbage white butterfly) larvae. from one of these strains (x. nematophilus pmfi296) a cosmid genome library was prepared in escherichia coli and screened for oral insecticidal activity. two overlapping cosmid clones were shown to encode insecticidal proteins, which had activity when expressed in e. coli (50% lethal concentration [lc(50)] of 2 to 6 microg of total protein/g of diet). the complete ... | 2001 | 11319082 |
| a phosphopantetheinyl transferase homolog is essential for photorhabdus luminescens to support growth and reproduction of the entomopathogenic nematode heterorhabditis bacteriophora. | the bacterium photorhabdus luminescens is a symbiont of the entomopathogenic nematode heterorhabditis bacteriophora. the nematode requires the bacterium for infection of insect larvae and as a substrate for growth and reproduction. the nematodes do not grow and reproduce in insect hosts or on artificial media in the absence of viable p. luminescens cells. in an effort to identify bacterial factors that are required for nematode growth and reproduction, transposon-induced mutants of p. luminescen ... | 2001 | 11325940 |
| description and application of a rapid method for genomic dna direct sequencing. | we describe a rapid method for determining nucleotide sequences directly from total genomic dna. this technique was used to determine genomic dna sequences in various prokaryotic and eukaryotic microorganisms with a g+c content between 40 and 50%, e.g. escherichia coli, vibrio cholerae, bacillus subtilis and saccharomyces cerevisiae. furthermore, the method was applied to accurately sequence up to 300 dna base pairs in photorhabdus luminescens, whose genome sequencing is currently under way. tak ... | 2001 | 11377872 |
| luxarray, a high-density, genomewide transcription analysis of escherichia coli using bioluminescent reporter strains. | a sequenced collection of plasmid-borne random fusions of escherichia coli dna to a photorhabdus luminescens luxcdabe reporter was used as a starting point to select a set of 689 nonredundant functional gene fusions. this group, called luxarray 1.0, represented 27% of the predicted transcriptional units in e. coli. high-density printing of the luxarray 1.0 reporter strains to membranes on agar plates was used for simultaneous reporter gene assays of gene expression. the cellular response to nali ... | 2001 | 11544210 |
| measuring virulence factor expression by the pathogenic bacterium photorhabdus luminescens in culture and during insect infection. | during insect infection photorhabdus luminescens emits light and expresses virulence factors, including insecticidal toxin complexes (tcs) and an rtx-like metalloprotease (prt). using quantitative pcr and protein assays, we describe the expression patterns of these factors both in culture and during insect infection and compare them to the associated bacterial growth curves. in culture, light and active prt protease are produced in stationary phase. tca also appears in stationary phase, whereas ... | 2001 | 11566980 |
| isolation and characterization of intracellular protein inclusions produced by the entomopathogenic bacterium photorhabdus luminescens. | cells of the entomopathogenic bacterium photorhabdus luminescens contain two types of morphologically distinct crystalline inclusion proteins. the larger rectangular inclusion (type 1) and a smaller bipyramid-shaped inclusion (type 2) were purified from cell lysates by differential centrifugation and isopycnic density gradient centrifugation. both structures are composed of protein and are readily soluble at ph 11 and 4 in 1% sodium dodecyl sulfate (sds) and in 8 m urea. electrophoretic analysis ... | 2001 | 11571191 |
| use of bioluminescent salmonella for assessing the efficiency of constructed phage-based biosorbent. | a bacteriophage-based biosorbent for salmonella enteritidis was constructed, and bacterial bioluminescence was used for assessment of the efficiency of cell capture. a strain of s. enteritidis with bioluminescent phenotype was constructed by transformation with plasmid pt7 carrying the entire lux operon from photorhabdus luminescens. the relation between relative light output (rlu) and colony-forming units (cfu/ml) of the bioluminescent strain was established. the bacteriophage specific to s. en ... | 2001 | 11641771 |
| oral toxicity of photorhabdus luminescens w14 toxin complexes in escherichia coli. | previous attempts to express the toxin complex genes of photorhabdus luminescens w14 in escherichia coli have failed to reconstitute their oral toxicity to the model insect manduca sexta. here we show that the combination of three genes, tcda, tcdb, and tccc, is essential for oral toxicity to m. sexta when expression in e. coli is used. further, when transcription from native toxin complex gene promoters is used, maximal toxicity in e. coli cultures is associated with the addition of mitomycin c ... | 2001 | 11679320 |