| photobactin: a catechol siderophore produced by photorhabdus luminescens, an entomopathogen mutually associated with heterorhabditis bacteriophora nc1 nematodes. | the nematode heterorhabditis bacteriophora transmits a monoculture of photorhabdus luminescens bacteria to insect hosts, where it requires the bacteria for efficient insect pathogenicity and as a substrate for growth and reproduction. siderophore production was implicated as being involved in the symbiosis because an ngra mutant inadequate for supporting nematode growth and reproduction was also deficient in producing siderophore activity and ngra is homologous to a siderophore biosynthetic gene ... | 2003 | 12902261 |
| insect resistance conferred by 283-kda photorhabdus luminescens protein tcda in arabidopsis thaliana. | the tcda gene of photorhabdus luminescens encodes a 283-kda protein, toxin a, that is highly toxic to a variety of insects, including some agriculturally important pests. we tested the efficacy of transgenic toxin a in arabidopsis thaliana for control of feeding insects. plants with toxin a expression above about 700 ng/mg of extractable protein were highly toxic to tobacco hornworm (manduca sexta). toxin a isolated from transgenic plants also strongly inhibited growth of the southern corn rootw ... | 2003 | 12949536 |
| breathing new life into insect-resistant plants. | | 2003 | 14520396 |
| the genome sequence of the entomopathogenic bacterium photorhabdus luminescens. | photorhabdus luminescens is a symbiont of nematodes and a broad-spectrum insect pathogen. the complete genome sequence of strain tt01 is 5,688,987 base pairs (bp) long and contains 4,839 predicted protein-coding genes. strikingly, it encodes a large number of adhesins, toxins, hemolysins, proteases and lipases, and contains a wide array of antibiotic synthesizing genes. these proteins are likely to play a role in the elimination of competitors, host colonization, invasion and bioconversion of th ... | 2003 | 14528314 |
| bacterial detection of the toxicity of dioxins, polychlorinated diphenyls, and polybrominated diphenyl ethers. | polychlorinated dibenzo-p-dioxins (pcdds), biphenyls (pcbs), and polybrominated diphenyl ethers (pbdes) were found to induce several specific stresses within bacterial cells. four different recombinant escherichia coli with specific stress promoters (i.e., the reca responsive to dna damage, faba responsive to membrane damage, katg responsive to oxidative damage, and grpe responsive to protein damage) that were fused to the lux operon from vibrio fischeri showed very unique specificities in terms ... | 2003 | 14551984 |
| sequence of a symbiont. | | 2003 | 14595358 |
| development of bespoke bioluminescent reporters with the potential for in situ deployment within a phenolic-remediating wastewater treatment system. | a suite of ecologically relevant, site-specific bioreporters was constructed by transposon mutagenesis of microorganisms isolated from a polluted phenolic-remediating wastewater treatment system. four pseudomonad species were engineered to carry a stable chromosomal copy of the lux operon (luxcdabe) derived from photorhabdus luminescens. these recombinant reporter microorganisms were tested for bioluminescence response to relevant phenol concentrations in the laboratory and to phenolic-containin ... | 2003 | 14607409 |
| expression of the photorhabdus luminescens lux genes (luxa, b, c, d, and e) in saccharomyces cerevisiae. | the luxa, b, c, d, and e genes from photorhabdus luminescens were cloned and functionally expressed in saccharomyces cerevisiae to construct a bacterial lux-based yeast bioreporter capable of autonomous bioluminescence emission. the bioreporter was engineered using a series of pbevy yeast expression vectors that allowed for bi-directional constitutive or inducible expression of the individual luxa, b, c, and e genes. the luxd gene, encoding the acyl-acp transferase that ultimately supplies the r ... | 2003 | 14654435 |
| effect of the insect pathogenic bacterium photorhabdus on insect phagocytes. | photorhabdus are insect pathogenic bacteria that replicate within the insect haemocoel following release from their entomopathogenic nematode symbionts. to investigate how they escape the cellular immune response we examined the effects of two strains of photorhabdus, w14 and k122, on manduca sexta phagocytes (haemocytes), in vitro and in vivo. following injection of esherichia coli into manduca larvae, these non-pathogenic bacteria are rapidly cleared from the haemolymph and the number of free ... | 2004 | 14678333 |
| the insecticidal toxin makes caterpillars floppy 2 (mcf2) shows similarity to hrma, an avirulence protein from a plant pathogen. | the photorhabdus luminescens w14 toxin encoding gene makes caterpillars floppy (mcf) was discovered due to its ability to kill caterpillars when expressed in escherichia coli. here we describe a homologue of mcf (renamed as mcf1), termed mcf2, discovered in the same genome. the mcf2 gene predicts another large toxin whose central domain, like mcf1, also shows limited homology to clostridium cytotoxin b. however, the n-terminus of mcf2 shows significant similarity to the type-iii secreted effecto ... | 2003 | 14680709 |
| a novel secreted protein toxin from the insect pathogenic bacterium xenorhabdus nematophila. | the bacterium xenorhabdus nematophila is an insect pathogen that produces several proteins that enable it to kill insects. screening of a cosmid library constructed from x. nematophila strain a24 identified a gene that encoded a novel protein that was toxic to insects. the 42-kda protein encoded by the toxin gene was expressed and purified from a recombinant system, and was shown to kill the larvae of insects such as galleria mellonella and helicoverpa armigera when injected at doses of around 3 ... | 2004 | 14707137 |
| in vivo expression of the mannose-resistant fimbriae of photorhabdus temperata k122 during insect infection. | photorhabdus temperata k122 is an entomopathogenic bacterium symbiotically associated with nematodes of the family heterorhabditidae: surface fimbriae are important for the colonization of many pathogenic bacteria, and here we report the nucleotide sequence and analysis of the expression of a 12-kbp fragment encoding the mannose-resistant fimbriae of p. temperata (mrf). the mrf gene cluster contains 11 genes with an organization similar to that of the mrp locus from proteus mirabilis. mrfi (enco ... | 2004 | 14729685 |
| the phop-phoq two-component regulatory system of photorhabdus luminescens is essential for virulence in insects. | photorhabdus luminescens is a symbiont of entomopathogenic nematodes. analysis of the genome sequence of this organism revealed a homologue of phop-phoq, a two-component system associated with virulence in intracellular bacterial pathogens. this organism was shown to respond to the availability of environmental magnesium. a mutant with a knockout mutation in the regulatory component of this system (phop) had no obvious growth defect. it was, however, more motile and more sensitive to antimicrobi ... | 2004 | 14973084 |
| the insecticidal toxin makes caterpillars floppy (mcf) promotes apoptosis in mammalian cells. | photorhabdus bacteria produce a number of toxins to kill their insect hosts. the expression of one of these, makes caterpillars floppy (mcf), is sufficient to allow escherichia coli to persist within and kill caterpillars. mcf causes shedding of the insect midgut epithelium and destructive blebbing of haemocytes suggesting it may trigger apoptosis. to investigate this hypothesis, here we examine the effects of e. coli-expressed mcf on the mammalian cell lines cos-7, nih 3t3 and hela cells. cells ... | 2004 | 15009026 |
| construction and characterization of novel dual stress-responsive bacterial biosensors. | using the genes for the green fluorescence protein and xenorhabdus luminescens luciferase operon and the promoters for the reca and katg genes, two stress-responsive escherichia coli biosensor strains have been constructed that can individually or concurrently respond to oxidative and genotoxic conditions. strain duo-1 carries the prgdk1 plasmid, which has the reca::gfpuv4 and katg::luxcdabe fusion genes oriented divergently with each other, while in duo-2, i.e., prgdk2, they are in a tandem ori ... | 2004 | 15018952 |
| pathogenomics. | the genomes described this month reflect the overall historical bias of microbial genomics towards pathogenic bacteria. although the balance is now being redressed to some extent, especially through the study of extremophiles, it is still the case that the opportunities provided by genomic studies are primarily taken up by those who study bacterial pathogenicity. this part of the field is, however, being broadened by including the study of pathogens of animals, insects and plants alongside those ... | 2003 | 15035020 |
| microbial infection causes the appearance of hemocytes with extreme spreading ability in monolayers of the tobacco hornworm manduca sexta. | the ability to adhere to and spread on a surface is a common property of insect blood cells. spreading on a glass surface by insect hemocytes is often used as a measure of immune fitness that can be inhibited by some insect pathogens and parasites. here, we report that upon infection of the tobacco hornworm manduca sexta with either a fungus (beauveria bassiana) or a bacterium (photorhabdus luminescens), a new type of hemocyte, not previously observed in healthy insects, was found in hemocyte mo ... | 2004 | 15043939 |
| human infection with photorhabdus asymbiotica: an emerging bacterial pathogen. | the three currently recognised photorhabdus species are bioluminescent bacteria that are pathogenic to insects. p. luminescens and p. temperata form a symbiotic relationship with nematodes that infect insects. p. asymbiotica, on the other hand, has only been isolated from human clinical specimens from the usa and australia. the bacterium has been associated with locally invasive soft tissue and disseminated bacteraemic infections. an invertebrate vector for p. asymbiotica has not yet been identi ... | 2004 | 15049334 |
| champions of versatility. | | 2004 | 15058278 |
| identification of a p2-related prophage remnant locus of photorhabdus luminescens encoding an r-type phage tail-like particle. | analysis of the photorhabdus luminescens genome sequence revealed that the pts region is related to the tail synthesis gene core of the p2 phage. the pts locus encodes a dna invertase homologue. pcr-rflp analysis showed the two potential tail fiber regions of the pts locus present dna inversions. electron microscopy revealed a phage tail-like particle, related to the r-type family and named r-photorhabdicin, in the culture supernatant of p. luminescens. mass spectrometry analysis of two sub-unit ... | 2004 | 15063490 |
| bacterial insecticidal toxins. | over the years it has been important for humans to control the populations of harmful insects and insecticides have been used for this purpose in agricultural and horticultural sectors. synthetic insecticides, owing to their various side effects, have been widely replaced by biological insecticides. in this review we attempt to describe three bacterial species that are known to produce insecticidal toxins of tremendous biotechnological, agricultural, and economic importance. bacillus thuringiens ... | 2004 | 15116762 |
| targeted photodynamic therapy of established soft-tissue infections in mice. | the worldwide rise in antibiotic resistance necessitates the development of novel antimicrobial strategies. although many workers have used photodynamic therapy (pdt) to kill bacteria in vitro, the use of this approach has seldom been reported in vivo in animal models of infection. we have previously described the first use of pdt to treat excisional wound infections by gram-(-) bacteria in living mice. however, these infected wound models involved a short timespan between infection (30 min) and ... | 2004 | 15122362 |
| burkholderia cenocepacia phage bcepmu and a family of mu-like phages encoding potential pathogenesis factors. | we have isolated bcepmu, a mu-like bacteriophage whose host range includes human pathogenic burkholderia cenocepacia (formally b. cepacia genomovar iii) isolates, and determined its complete 36748 bp genomic sequence. like enteric bacteriophage mu, the bcepmu genomic dna is flanked by variable host sequences, a result of transposon-mediated replication. the bcepmu genome encodes 53 proteins, including capsid assembly components related to those of mu, and tail sheath and tube proteins related to ... | 2004 | 15184022 |
| cloning and heterologous expression of a novel insecticidal gene (tccc1) from xenorhabdus nematophilus strain. | we have identified and cloned a novel toxin gene (tccc1/xptb1) from xenorhabdus nematophilus strain isolated from korea-specific entomophagous nematode steinernema glaseri mk. the dna sequence of cloned toxin gene (3048 bp) has an open reading frame encoding 1016 amino acids with a predicted molecular mass of 111058 da. the toxin sequence shares 50-96% identical amino acid residues with the previously reported tccc1 cloned from x. nematophilus, photorhabdus luminescens w14 p. luminescens tto1, a ... | 2004 | 15194482 |
| variation in the effectors of the type iii secretion system among photorhabdus species as revealed by genomic analysis. | entomopathogenic bacteria of the genus photorhabdus harbor a type iii secretion system. this system was probably acquired prior to the separation of the species within this genus. furthermore, the core components of the secretion machinery are highly conserved but the predicted effectors differ between photorhabdus luminescens and p. asymbiotica, two highly related species with different hosts. | 2004 | 15205440 |
| purification and characterization of two distinct metalloproteases secreted by the entomopathogenic bacterium photorhabdus sp. strain az29. | photorhabdus sp. strain az29 is symbiotic with an azorean nematode of the genus heterorhabditis in a complex that is highly virulent to insects even at low temperatures. the virulence of the bacteria is mainly attributed to toxins and bacterial enzymes secreted during parasitism. the bacteria secrete proteases during growth, with a peak at the end of the exponential growth phase. protease secretion was higher in cultures growing at lower temperatures. at 10 degrees c the activity was highest and ... | 2004 | 15240252 |
| interference competition and parasite virulence. | within-host competition between parasites, a consequence of infection by multiple strains, is predicted to favour rapid host exploitation and greater damage to hosts (virulence). however, the inclusion of biological variables can drastically change this relationship. for example, if competing parasite strains produce toxins that kill each other (interference competition), their growth rates and virulence may be reduced relative to single-strain infections. bacteriocins are antimicrobial toxins p ... | 2004 | 15255095 |
| cloning serratia entomophila antifeeding genes--a putative defective prophage active against the grass grub costelytra zealandica. | serratia entomophila and serratia proteamaculans (enterobacteriaceae) 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 155-kb plasmid, padap, carries the genes sepa, sepb, and sepc, which are essential for production of amber disease symptoms. transposon insertions in any of the sep genes in padap abol ... | 2004 | 15262948 |
| two new bacterial pathogens of colorado potato beetle coleoptera: chrysomelidae). | other than bacillus thuringiensis berliner, few bacteria are lethal to the colorado potato beetle (leptinotarsa decemlineata [say]), a major pest of potatoes and eggplant. expanded use of biologicals for the control of colorado potato beetle will improve resistance management, reduce pesticide use, and produce novel compounds for potential use in transgenic plants. using freeze-dried, rehydrated artificial diet in pellet form to screen bacteria lethal to other insects, we determined that strains ... | 2004 | 15279252 |
| taxonomy of australian clinical isolates of the genus photorhabdus and proposal of photorhabdus asymbiotica subsp. asymbiotica subsp. nov. and p. asymbiotica subsp. australis subsp. nov. | the relationship of photorhabdus isolates that were cultured from human clinical specimens in australia to photorhabdus asymbiotica isolates from human clinical specimens in the usa and to species of the genus photorhabdus that are associated symbiotically with entomopathogenic nematodes was evaluated. a polyphasic approach that involved dna-dna hybridization, phylogenetic analyses of 16s rrna and gyrb gene sequences and phenotypic characterization was adopted. these investigations showed that g ... | 2004 | 15280306 |
| organ specificity, colonization and clearance dynamics in vivo following oral challenges with the murine pathogen citrobacter rodentium. | citrobacter rodentium belongs to a family of human and animal enteric pathogens that includes the clinically significant enterohaemorrhagic escherichia coli (ehec) and enteropathogenic e. coli (epec). these pathogens use attaching and effacing (a/e) lesions to colonize the host gastrointestinal tract. in this study we have used bioluminescence imaging (bli) to investigate the organ specificity, dynamics of colonization and clearance of mice by c. rodentium in situ and in real time. the biolumine ... | 2004 | 15339271 |
| random mutagenesis of bacterial luciferase: critical role of glu175 in the control of luminescence decay. | 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 photobacterium fisheri, p. phosphoreum and p. leiognathi, have rapid decay rates. by substitution of a 67-amino-acid stretch of p. phosphoreum luxa in the central region of the luxa subunit, the ... | 2005 | 15352872 |
| enhancement of the multi-channel continuous monitoring system through the use of xenorhabdus luminescens lux fusions. | the enhancement of the multi-channel continuous toxicity monitoring system developed previously was studied. to achieve better and more stable results from the system, the use of thermo-lux fusion strains that express the luxcdabe genes from xenorhabdus luminescens was evaluated. a total of six recombinant escherichia coli strains with the promoters from three oxidative-stress responsive genes, i.e. the katg, soda and pqi-5 genes, fused to either the lux genes from vibrio fischeri or x. luminesc ... | 2004 | 15494228 |
| identification of photorhabdus asymbiotica in cases of human infection. | | 2003 | 15508515 |
| insect cellular and chemical limitations to pathogen development: the colorado potato beetle, the nematode heterorhabditis marelatus, and its symbiotic bacteria. | this research examines possible factors limiting pathogen development and reproduction in a novel host insect. the nematode heterorhabditis marelatus and its symbiotic bacterium, photorhabdus luminescens, kill 98% of nematode-treated colorado potato beetle (cpb) prepupae, but the nematode reproduces in only 1-6% of beetles. we examined nematode/bacterial inhibition at each step of the normal developmental pathway to determine host feature(s) limiting nematode reproduction. we found that in vivo ... | 2004 | 15579320 |
| the pbgpe operon in photorhabdus luminescens is required for pathogenicity and symbiosis. | photorhabdus is a genus of gram-negative enterobacteriaceae that is pathogenic to insect larvae while also maintaining a mutualistic relationship with nematodes from the family heterorhabditis, where the bacteria occupy the gut of the infective juvenile (ij) stage of the nematode. in this study we describe the identification and characterization of a mutation in the pbge1 gene of photorhabdus luminescens tt01, predicted to be the fifth gene in the pbgpe operon. we show that this mutant, bmm305, ... | 2005 | 15601690 |
| astr-asts, a new two-component signal transduction system, mediates swarming, adaptation to stationary phase and phenotypic variation in photorhabdus luminescens. | photorhabdus luminescens is an insect-pathogenic bacterium that forms a symbiosis with specific entomopathogenic nematodes. in this bacterium, a symbiosis-'deficient' phenotypic variant (known as the secondary variant or form ii) arises at a low frequency during prolonged incubation. a knock-out mutant was generated of the regulator of a newly identified two-component regulatory system, designated astr-asts. interestingly, this mutation altered the timing of phenotypic switching. variant cells a ... | 2004 | 15073299 |
| effect of human serum on bioluminescence of natural and recombinant luminescent bacteria. | biphasic modification of bacterial bioluminescence by human serum was revealed: bioluminescence was inhibited at high concentrations of the serum and stimulated at low concentrations. effects of temperature and duration of exposure on bioluminescence manifested in stimulation of the inhibitory effect at higher temperature and longer exposure. the degree of inhibition of bioluminescence under in the presence of serum depends on species characteristics of the microorganism and nature of the lumine ... | 2004 | 15665923 |
| two new subspecies of photorhabdus luminescens, isolated from heterorhabditis bacteriophora (nematoda: heterorhabditidae): photorhabdus luminescens subsp. kayaii subsp. nov. and photorhabdus luminescens subsp. thracensis subsp. nov. | bacterial isolates from nematodes from turkish soil samples were initially characterized by molecular methods and seven members of the genus photorhabdus identified to the species level, using riboprint analyses and metabolic properties. strain 07-5 (dsm 15195) was highly related to the type strain of photorhabdus luminescens subsp. laumondii dsm 15139t, and was regarded a strain of this subspecies. strains 1121t (dsm 15194t), 68-3 (dsm 15198) and 47-10 (dsm 15197) formed one, strain 39-8t (dsm ... | 2004 | 15053319 |
| enzymic characterization with progress curve analysis of a collagen peptidase from an enthomopathogenic bacterium, photorhabdus luminescens. | a proteolytic enzyme, php-b ( photorhabdus protease b), was purified from the entomopathogenic bacterium, photorhabdus luminescens. the enzyme is intracellular, and its molecular mass is 74 kda. tested on various peptide and oligopeptide substrates, php-b hydrolysed only oligopeptides, with significant activity against bradykinin and a 2-furylacryloyl-blocked peptide, fua-lgpa (2-furylacryloyl-leu-gly-pro-ala; kcat=3.6x10(2) s(-1), k(m)=5.8x10(-5) m(-1), ph optimum approx. 7.0). the p k(a1) and ... | 2004 | 14744262 |
| genetic and biochemical characterization of prta, an rtx-like metalloprotease from photorhabdus. | proteases play a key role in the interaction between pathogens and their hosts. the bacterial entomopathogen photorhabdus lives in symbiosis with nematodes that invade insects. following entry into the insect, the bacteria are released from the nematode gut into the open blood system of the insect. here they secrete factors which kill the host and also convert the host tissues into food for the replicating bacteria and nematodes. one of the secreted proteins is prta, which is shown here to be a ... | 2003 | 12777498 |
| comparison of the bioluminescence of photorhabdus species and subspecies type strains. | natural bioluminescence of all recently accepted photorhabdus species and subspecies type strains (bacterial symbionts of entomopathogenic nematodes) was measured using a commercial luminometer; optimum conditions for the measurement were described. cultures emitted reliably measurable bioluminescence with characteristic level and kinetics for each strain. bioluminescence of all strains was significantly higher at 37 than at 25 degrees c at the beginning of the measurement, no effect of bacteria ... | 2004 | 15702542 |
| for the insect pathogen photorhabdus luminescens, which end of a nematode is out? | the nematode heterorhabditis bacteriophora is the vector for transmitting the entomopathogenic bacterium photorhabdus luminescens between insect larvae. the dauer juvenile (dj) stage nematode selectively retains p. luminescens in its intestine until it releases the bacteria into the hemocoel of an insect host. we report the results of studying the transmission of the bacteria by its nematode vector. cells of p. luminescens labeled with green fluorescent protein preferentially colonized a region ... | 2003 | 12676661 |
| regulation and biosynthesis of carbapenem antibiotics in bacteria. | carbapenem antibiotics are members of the beta-lactam family of antibiotics, the most important class of antibiotics currently in clinical use. they are active against many important gram-positive and gram-negative pathogens. one important feature of carbapenem antibiotics is their resistance to several beta-lactamases. thienamycin, isolated from streptomyces cattleya, was the first carbapenem described. other well-studied carbapenems were isolated from the gram-negative bacteria erwinia carotov ... | 2005 | 15759042 |
| [sequencing and comparative analysis of the lux operon of photorhabdus luminescens strain zm1: eric elements as putative recombination spots]. | the ecori chromosomal fragment (6782 bp) containing the lux operon of photorhabdus luminescens was cloned in puc18 and completely sequenced. enteric repetitive intergenic consensus (eric), an imperfect palindrome (125-127 bp) characteristics for enterobacteriaceae genomes, was found in three sites. strain zm1 proved to differ in eric number and location from strains hb, hm, and hw. nucleotide substitution analysis showed that luxc and luxb, which are more than 1 kb away from eric, are similar to ... | 2002 | 12391842 |
| construction and evaluation of nagr-nagaa::lux fusion strains in biosensing for salicylic acid derivatives. | the nagr protein is a response regulatory protein found in the bacterium ralstonia sp. u2 that is involved in sensing for salicylic acid and the subsequent induction of the operon just upstream of its gene. the genes encoded for in this operon are involved in the degradation of salicylic acid. escherichia coli strain rfm443 carrying a fusion of the photorhabdus luminescens luxcdabe operon with the nagr gene and upstream region of the nagaa gene was constructed and characterized with respect to i ... | 2005 | 15767693 |
| cloning and sequencing of a genomic island found in the brazilian purpuric fever clone of haemophilus influenzae biogroup aegyptius. | a genomic island was identified in the haemophilus influenzae biogroup aegyptius brazilian purpuric fever (bpf) strain f3031. this island, which was also found in other bpf isolates, could not be detected in non-bpf biogroup aegyptius strains or in nontypeable or typeable h. influenzae strains, with the exception of a region present in the type b eagan strain. this 34,378-bp island is inserted, in reference to h. influenzae rd kw20, within a choline transport gene and contains a mosaic structure ... | 2005 | 15784532 |
| the photorhabdus pir toxins are similar to a developmentally regulated insect protein but show no juvenile hormone esterase activity. | the genome of the insect pathogen photorhabdus luminescens strain tt01 contains numerous genes predicting toxins and proteases. within the p. luminescens tt01 genome, the products of two loci, plu 4093-plu 4092 and plu 4437-plu 4436, show oral insecticidal activity against both moth and mosquito larvae. the proteins encoded by these loci, here termed 'photorhabdus insect related' (pir) proteins a and b, show similarity both to delta-endotoxins from bacillus thuringiensis (bts) and a developmenta ... | 2005 | 15796978 |
| identification, characterization, and regulation of a cluster of genes involved in carbapenem biosynthesis in photorhabdus luminescens. | the luminescent entomopathogenic bacterium photorhabdus luminescens produces several yet-uncharacterized broad-spectrum antibiotics. we report the identification and characterization of a cluster of eight genes (named cpma to cpmh) responsible for the production of a carbapenem-like antibiotic in strain tt01 of p. luminescens. the cpm cluster differs in several crucial aspects from other car operons. the level of cpm mrna peaks during exponential phase and is regulated by a rap/hor homolog ident ... | 2002 | 12147472 |
| the exbd gene of photorhabdus temperata is required for full virulence in insects and symbiosis with the nematode heterorhabditis. | photorhabdus are bacteria found colonizing the gut of a specialized stage of the nematode heterorhabditis, called the infective juvenile (ij). the ij is a free-living stage of the nematode that seeks out and infects insect larvae. once inside the insect the ij release photorhabdus into the haemolymph where the bacteria rapidly proliferate, killing the insect within 48-72 h. the nematodes grow and reproduce in the insect cadaver by feeding on the photorhabdus biomass. in this study we use photorh ... | 2005 | 15819630 |
| evolutionary relationships of three new species of enterobacteriaceae living as symbionts of aphids and other insects. | ecological studies on three bacterial lineages symbiotic in aphids have shown that they impose a variety of effects on their hosts, including resistance to parasitoids and tolerance to heat stress. phylogenetic analyses of partial sequences of gyrb and reca are consistent with previous analyses limited to 16s rrna gene sequences and yield improved confidence of the evolutionary relationships of these symbionts. all three symbionts are in the enterobacteriaceae. one of the symbionts, here given t ... | 2005 | 15933033 |
| imaging of light emission from the expression of luciferases in living cells and organisms: a review. | luciferases are enzymes that emit light in the presence of oxygen and a substrate (luciferin) and which have been used for real-time, low-light imaging of gene expression in cell cultures, individual cells, whole organisms, and transgenic organisms. such luciferin-luciferase systems include, among others, the bacterial lux genes of terrestrial photorhabdus luminescens and marine vibrio harveyi bacteria, as well as eukaryotic luciferase luc and ruc genes from firefly species (photinus) and the se ... | 2002 | 11816060 |
| oral toxicity of photorhabdus toxins against thrips species. | the oral toxicity of excretion products of several photorhabdus and xenorhabdus strains was tested on two thrips species: frankliniella occidentalis and thrips tabaci. out of 46 photorhabdus isolates and six xenorhabdus isolates only six north american p. temperata isolates were toxic to the thrips species. after 7 days of drinking from p. temperata supernatant a mortality of 90% could be reached. thrips were also killed after sucking from leaves covered with the toxins. toxins have a negative e ... | 2005 | 15955338 |
| two groups of entomopathogenic bacteria, photorhabdus and xenorhabdus, share an inhibitory action against phospholipase a2 to induce host immunodepression. | photorhabdus and xenorhabdus are two genera of entomopathogenic bacteria having a mutualistic relationship with their respective nematode hosts, heterorhabditis and steinernema. one of the pathogenic mechanisms of these bacteria includes host immunodepression, which leads to lethal septicemia. it has been known that x. nematophila inhibits phospholipase a2 (pla2) to induce host immunodepression. here, we tested the hypothesis of pla2 inhibition using another bacterial species involved in other g ... | 2005 | 15979640 |
| the gene stla encodes a phenylalanine ammonia-lyase that is involved in the production of a stilbene antibiotic in photorhabdus luminescens tt01. | photorhabdus is a genus of gram-negative bacteria from the family enterobacteriaceae. members of photorhabdus have a complex life cycle during which the bacterium has a pathogenic interaction with insect larvae whilst also maintaining a mutualistic relationship with nematodes from the family heterorhabditidae. during growth in the insect, photorhabdus bacteria produce a broad-spectrum antibiotic identified as 3,5-dihydroxy-4-isopropylstilbene (st). the biochemical pathway responsible for the pro ... | 2005 | 16079333 |
| photorhabdus asymbiotica, a pathogen emerging on two continents that proves that there is no substitute for a well-trained clinical microbiologist. | a 54-year-old ranch hand presented to the emergency room with an alleged spider bite and multiple abscesses. both wound and blood cultures grew photorhabdus asymbiotica, an enteric gram-negative rod that was initially misidentified by the hospital's rapid identification system. clinical laboratories should be aware of the limitations of their rapid identification systems and always use them as an adjunct to analysis of morphological and phenotypic traits. | 2005 | 16081963 |
| the family of serratia type pore forming toxins. | the serratia marcescens hemolysin represents the prototype of a growing family of pore forming toxins. the available bacterial genome sequences reveal serratia hemolysin homologues in additional species. however, only s. marcescens hemolysin has been studied in great molecular detail. this family of toxins has nothing in common with the pore forming toxins of e. coli type (rtx toxins), the staphylococcus aureus alpha-toxin or the thiol activated toxin of group a beta-hemolytic streptococci (stre ... | 2005 | 16101433 |
| specialization of the entomopathogenic nematode steinernema scapterisci with its mutualistic xenorhabdus symbiont. | the level of specialization of the entomopathogenic nematode steinernema scapterisci with its native xenorhabdus symbiont was investigated by testing (1) the influence of non-native bacterial strains on nematode fitness within an insect-host (galleria mellonella) and (2) specificity of the association between the nematode infective juveniles and non-native bacteria. all non-native xenorhabdus spp. or photorhabdus spp. strains tested were mutualistically associated with other entomopathogenic nem ... | 2005 | 16163505 |
| homologues of insecticidal toxin complex genes in yersinia enterocolitica biotype 1a and their contribution to virulence. | yersinia enterocolitica is an enteric pathogen that consists of six biotypes: 1a, 1b, 2, 3, 4, and 5. strains of the latter five biotypes can carry a virulence plasmid, known as pyv, and several well-characterized chromosomally encoded virulence determinants. y. enterocolitica strains of biotype 1a lack the virulence-associated markers of pyv-bearing strains and were once considered to be avirulent. there is growing epidemiological, clinical, and experimental evidence, however, to suggest that s ... | 2005 | 16177365 |
| 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 |
| identification and phylogenetic analysis of arsenophonus- and photorhabdus-type bacteria from adult hippoboscidae and streblidae (hippoboscoidea). | this is the first report of arsenophonus- and photorhabdus-type bacteria from streblidae (bat flies) and hippoboscidae (louse flies, keds). strains were detected by means of polymerase chain reaction of 16s rdna, and phylogenetic analysis determined the relationship of the obtained sequences to previously reported sequences in genbank. phylogenetic analysis by means of maximum parsimony revealed that all isolated arsenophonus spp. 16s rdna sequences formed a monophyletic sub-clade within other i ... | 2006 | 16289111 |
| 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 |
| phase variation in xenorhabdus nematophilus and photorhabdus luminescens: differences in respiratory activity and membrane energization. | phase variation in xenorhabdus and photorhabdus spp. has a significant impact on their symbiotic relationship with entomopathogenic nematodes by altering the metabolic by-products upon which the nematodes feed. the preferential retention of the phase i variant by the infective-stage nematode and its better support for nematode reproduction than phase ii indicates its importance in the bacterial-nematode interactions. however, there is no obvious role for phase ii in these interactions. this stud ... | 1994 | 16349145 |
| divergence and mosaicism among virulent soil phages of the burkholderia cepacia complex. | we have determined the genomic sequences of four virulent myophages, bcep1, bcep43, bcepb1a, and bcep781, whose hosts are soil isolates of the burkholderia cepacia complex. despite temporal and spatial separations between initial isolations, three of the phages (bcep1, bcep43, and bcep781, designated the bcep781 group) exhibit 87% to 99% sequence identity to one another and most coding region differences are due to synonymous nucleotide substitutions, a hallmark of neutral genetic drift. phage b ... | 2006 | 16352842 |
| whole-genome comparison between photorhabdus strains to identify genomic regions involved in the specificity of nematode interaction. | the bacterium photorhabdus establishes a highly specific association with heterorhabditis, its nematode host. photorhabdus strains associated with heterorhabditis bacteriophora or heterorhabditis megidis were compared using a photorhabdus dna microarray. we describe 31 regions belonging to the photorhabdus flexible gene pool. distribution analysis of regions among the photorhabdus genus identified loci possibly involved in nematode specificity. | 2006 | 16385072 |
| low temperature-induced insecticidal activity of yersinia enterocolitica. | the insecticidal toxin complexes (tcs) are produced by several enterobacteriaceae associated with insects, such as photorhabdus luminescens, serratia entomophila and xenorhabdus nematophilus. genome sequences revealed tc-like genes in yersinia spp., but insecticidal activity of this genus associated with the toxins has not been described. through the search for genes upregulated at low growth temperatures in yersinia enterocolitica strain w22703, a genomic island of 19 kb termed tc-pai(ye) with ... | 2006 | 16390445 |
| autoinducer 2 affects biofilm formation by bacillus cereus. | cell-free supernatants from growing bacillus cereus strain atcc 10987 induced luminescence in a photorhabdus luminescens deltaluxs mutant, indicating the production of functional autoinducer 2 (ai-2). the exogenous addition of in vitro synthesized ai-2 had an inhibitory effect on biofilm formation by b. cereus and promoted release of the cells from a preformed biofilm. | 2006 | 16391139 |
| on the mechanisms of photodynamic effect of sensitizers and improvement of methods of their primary selection for photodynamic antimicrobial therapy. | | 2005 | 16392758 |
| 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 |
| nutritive significance of crystalline inclusion proteins of photorhabdus luminescens in steinernema nematodes. | phase i cells of photorhabdus luminescens produce two types of intracellular crystalline inclusion proteins designated cipa and cipb. the genes encoding cipa and cipb proteins from p. luminescens h06 were expressed respectively in escherichia coli and these cells were used to feed the axenic first juveniles (j1) of three steinernema nematode isolates in liquid cultures and on agar plates. in liquid cultures, the axenic j1 juveniles of all three test steinernema nematode isolates were able to pro ... | 2006 | 16420626 |
| 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 |
| txp40, a ubiquitous insecticidal toxin protein from xenorhabdus and photorhabdus bacteria. | xenorhabdus and photorhabdus are gram-negative bacteria that produce a range of proteins that are toxic to insects. we recently identified a novel 42-kda protein from xenorhabdus nematophila that was lethal to the larvae of insects such as galleria mellonella and helicoverpa armigera when it was injected at doses of 30 to 40 ng/g larvae. in the present work, the toxin gene txp40 was identified in another 59 strains of xenorhabdus and photorhabdus, indicating that it is both highly conserved and ... | 2006 | 16461722 |
| the essential tyrosine-containing loop conformation and the role of the c-terminal multi-helix region in eukaryotic phenylalanine ammonia-lyases. | besides the post-translationally cyclizing catalytic ala-ser-gly triad, tyr110 and its equivalents are of the most conserved residues in the active site of phenylalanine ammonia-lyase (pal, ec 4.3.1.5), histidine ammonia-lyase (hal, ec 4.3.1.3) and other related enzymes. the tyr110phe mutation results in the most pronounced inactivation of pal indicating the importance of this residue. the recently published x-ray structures of pal revealed that the tyr110-loop was either missing (for rhodosprid ... | 2006 | 16478474 |
| the regulation of pathogenicity and mutualism in photorhabdus. | photorhabdus is a genus of insect-pathogenic bacteria that also maintains a mutualistic interaction with heterorhabditid nematodes. bacteria in this genus are members of the family enterobacteriaceae and are, therefore, closely related to many important mammalian pathogens. this bacteria-nematode complex has been exploited as a biocontrol agent that is active against several insect pests. however, this model system is also uniquely placed to address important fundamental questions about pathogen ... | 2006 | 16480919 |
| photorhabdus virulence cassettes confer injectable insecticidal activity against the wax moth. | two recently sequenced genomes of the insect-pathogenic bacterium photorhabdus and a large serratia entomophila plasmid, padap, have phage-related loci containing putative toxin effector genes, designated the "photorhabdus virulence cassettes" (pvcs). in s. entomophila, the single plasmid pvc confers antifeeding activity on larvae of a beetle. here, we show that recombinant escherichia coli expressing pvc-containing cosmids from photorhabdus has injectable insecticidal activity against larvae of ... | 2006 | 16513755 |
| the phytopathogen dickeya dadantii (erwinia chrysanthemi 3937) is a pathogen of the pea aphid. | dickeya dadantii (erwinia chrysanthemi) is a phytopathogenic bacterium causing soft rot diseases on many crops. the sequencing of its genome identified four genes encoding homologues of the cyt family of insecticidal toxins from bacillus thuringiensis, which are not present in the close relative pectobacterium carotovorum subsp. atrosepticum. the pathogenicity of d. dadantii was tested on the pea aphid acyrthosiphon pisum, and the bacterium was shown to be highly virulent for this insect, either ... | 2006 | 16517643 |
| polyclonal antisera to distinguish strains and form variants of photorhabdus (xenorhabdus) luminescens. | in this study antisera against photorhabdus luminescens strains were prepared for the first time. p. luminescens is a bacterial symbiont of entomopathogenic nematodes belonging to the genus heterorhabditis. to characterize p. luminescens strains and form variants, we produced polyclonal antisera against p. luminescens pe (obtained from nematode strain nlh-e87.3) and against the primary and secondary forms of p. luminescens psh (obtained from nematode strain dh-sh1). in double-diffusion tests all ... | 1995 | 16534911 |
| influence of osmolarity on phase shift in photorhabdus luminescens. | the influence of osmolarity and other environmental factors like low oxygen levels, light, extreme ph values, and temperatures on phase variation of photorhabdus luminescens, the symbiotic bacterium of entomopathogenic nematodes of the genus heterorhabditis, was investigated. only subculturing in low-osmolarity medium triggered a phase shift to secondary phase reliably. | 1995 | 16535154 |
| composition and biophysical properties of lipids in xenorhabdus nematophilus and photorhabdus luminescens, symbiotic bacteria associated with entomopathogenic nematodes. | primary and secondary forms of photorhabdus luminescens hm and xenorhabdus nematophilus n2-4 were grown at 18 and 28(deg)c for 24 to 96 h, and we made determinations of the fatty-acid compositions of total lipids and of the fluidity measured by 5-doxyl-stearic acid embedded in liposomes made from total lipids. the levels of the unsaturated fatty acids 16:1 and 18:1 (those with chain lengths of 16 or 18 and one double bond) generally were higher in primary-phase variants of p. luminescens grown a ... | 1997 | 16535651 |
| 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 |
| rnai suppression of recognition protein mediated immune responses in the tobacco hornworm manduca sexta causes increased susceptibility to the insect pathogen photorhabdus. | bacterial pathogens either hide from or overcome the immune response of their hosts. here we show that two different species of insect pathogenic bacteria, photorhabdus luminescens tt01 and photorhabdus asymbiotica atcc43949, were both recognized by the immune system of their host manduca sexta, as indicated by a rapid increase in the levels of mrnas encoding three different inducible microbial recognition proteins, hemolin, immulectin-2 and peptidoglycan recognition protein. rna interference (r ... | 2006 | 16620974 |
| 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 |
| a novel antimicrobial epoxide isolated from larval galleria mellonella infected by the nematode symbiont, photorhabdus luminescens (enterobacteriaceae). | a novel antimicrobial epoxide, 2-isopropyl-5-(3-phenyl-oxiranyl)-benzene-1,3-diol (1), was identified from larval galleria mellonella infected by a symbiotically associated bacterium-nematode complex (photorhabdus luminescens c9-heterorhabditis megidis 90). its structure was determined with spectroscopic analysis and confirmed by chemical synthesis starting from a known antibiotic, 2-isopropyl-5-(2-phenylethenyl)-benzene-1,3-diol (2). epoxide 1 was active against bacillus subtilis, escherichia c ... | 2006 | 16644226 |
| search for fucose binding domains in recently sequenced hypothetical proteins using molecular modeling techniques and structural analysis. | the crystal structure of a fucose-binding lectin from the bacteria pseudomonas aeruginosa in complex with alpha-l-fucose has been recently determined. it is a tetramer; each monomer displays a nine-stranded, antiparallel, beta-sandwiched arrangement and contains two calcium ions that mediate the binding of fucose in a recognition mode unique among protein-carbohydrate interactions. in search of this type of unique interactions in other newly discovered protein sequences, we have used molecular m ... | 2006 | 16691508 |
| outer membrane protein genes and their small non-coding rna regulator genes in photorhabdus luminescens. | three major outer membrane protein genes of escherichia coli, ompf, ompc, and ompa respond to stress factors. transcripts from these genes are regulated by the small non-coding rnas micf, micc, and mica, respectively. here we examine photorhabdus luminescens, an organism that has a different habitat from e. coli for outer membrane protein genes and their regulatory rna genes. | 2006 | 16716220 |
| prior infection of manduca sexta with non-pathogenic escherichia coli elicits immunity to pathogenic photorhabdus luminescens: roles of immune-related proteins shown by rna interference. | prior infection of manduca sexta caterpillars with the non-pathogenic bacterium escherichia coli elicits effective immunity against subsequent infection by the usually lethal and highly virulent insect pathogen photorhabdus luminescens tt01. induction of this protective effect is associated with up-regulation of both microbial pattern recognition protein genes (hemolin, immulectin-2 and peptidoglycan recognition protein) and anti-bacterial effector genes (attacin, cecropin, lebocin, lysozyme and ... | 2006 | 16731347 |
| yersiniabactin production by pseudomonas syringae and escherichia coli, and description of a second yersiniabactin locus evolutionary group. | the siderophore and virulence factor yersiniabactin is produced by pseudomonas syringae. yersiniabactin was originally detected by high-pressure liquid chromatography (hplc); commonly used pcr tests proved ineffective. yersiniabactin production in p. syringae correlated with the possession of irp1 located in a predicted yersiniabactin locus. three similarly divergent yersiniabactin locus groups were determined: the yersinia pestis group, the p. syringae group, and the photorhabdus luminescens gr ... | 2006 | 16751485 |
| direct infection of spodoptera litura by photorhabdus luminescens encapsulated in alginate beads. | actively growing cultures of photorhabdus luminescens were encapsulated in sodium alginate beads and examined for their ability to infect insect hosts. these beads, containing approximately 2.5 x 10(7)photorhabdus cells per bead, when mixed with sterilized soil and exposed to spodoptera litura larvae resulted in 100% mortality in 48 h, while the use of alginate encapsulated heterorhabditis nematode resulted in 40% mortality after 72 h. the bacteria were reisolated from the dead insect thus provi ... | 2006 | 16828112 |
| development of bioluminescent edwardsiella ictaluri for noninvasive disease monitoring. | edwardsiella ictaluri is a facultative intracellular bacterium that causes enteric septicemia of catfish (esc). in this study, we aimed to develop bioluminescent e. ictaluri that can be monitored by noninvasive bioluminescence imaging (bli). to accomplish this, the luxcdabe operon of photorhabdus luminescens was cloned downstream of the lacz promoter in the broad host range plasmid pbbr1mcs4. edwardsiella ictaluri strain 93-146 transformed with the new plasmid, paklux1, was highly bioluminescent ... | 2006 | 16842347 |
| beta-galactosidase production by streptococcus thermophilus is higher in the small intestine than in the caecum of human-microbiota-associated mice after lactose supplementation. | transit kinetics and survival rates of a bacterial species from yoghurt (i.e. streptococcus thermophilus strain fbi3) were examined in different digestive compartments of gnotoxenic and human-microbiota-associated mice. the production of the lactose-hydrolysing enzyme (i.e. beta-galactosidase) was also investigated within the digestive tract, using a chromosomal reporter system based on luciferase genes from photorhabdus luminescens under the control of the plac promoter. in both mice models, s. ... | 2006 | 16870007 |
| stability of entomopathogenic bacteria, xenorhabdus nematophila and photorhabdus luminescens, during in vitro culture. | the entomopathogenic nematode-bacteria complexes heterorhabditis bacteriophora/photorhabdus luminescens and steinernema carpocapsae/xenorhabdus nematophila are mass produced for use as biological insecticides. stability of the bacterial partner in culture is essential for maintaining traits important for both biological control and production. two geographically distinct strains of each bacterial species were isolated from their nematode partners and serially subcultured on in vitro media to ass ... | 2007 | 16941119 |
| spite. | | 2006 | 16950082 |
| ytxr, a conserved lysr-like regulator that induces expression of genes encoding a putative adp-ribosyltransferase toxin homologue in yersinia enterocolitica. | yersinia enterocolitica causes human gastroenteritis, and many isolates have been classified as either "american" or "non-american" strains based on their geographic prevalence and virulence properties. in this study we describe identification of a transcriptional regulator that controls expression of the y. enterocolitica ytxab genes. the ytxab genes have the potential to encode an adp-ribosylating toxin with similarity to pertussis toxin. however, a ytxab null mutation did not affect virulence ... | 2006 | 16997967 |
| comparison of bulb syringe and pulsed lavage irrigation with use of a bioluminescent musculoskeletal wound model. | despite the fact that wound irrigation is a common surgical procedure, there are many variables, including delivery device, irrigant type, and fluid volume, that have yet to be optimized. the purpose of this study was to compare, with use of transgenic bioluminescent bacteria and standard quantitative microbiological methods, the efficacy of pulsed lavage and bulb syringe irrigation in reducing wound bacterial counts. | 2006 | 17015593 |
| 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 |
| [host factors in the regulation of the vibrio fischeri lux operon in escherichia coli cells]. | it has been shown that the chaperonin groel, together with groes co-chaperonin and lon atp-dependent protease are involved in the regulation of expression of the vibrio fischeri lux operon in escherichia coli cells. the cells of e. coli groe (pf1)- bearing a plasmid with the complete v. fischeri lux regulon were weakly luminescent. the cells of e. coli lona (pf1) displayed intense bioluminescence. the same effects also occurred in mutant e. coli strains bearing a hybrid plasmid pvfr1, where the ... | 2006 | 17025179 |
| 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 |
| the broadly insecticidal photorhabdus luminescens toxin complex a (tca): activity against the colorado potato beetle, leptinotarsa decemlineata, and sweet potato whitefly, bemisia tabaci. | toxin complex a (tca), a high molecular weight insecticidal protein complex produced by the entomopathogenic bacterium photorhabdus luminescens, has been found to be orally toxic to both the colorado potato beetle, leptinotarsa decemlineata, and the sweet potato whitefly, bemisia tabaci biotype b. the 48 hour lc50 for tca against neonate l. decemlineata was found to be 2.7 ppm, and the growth of 2nd instar l. decemlineata exposed to tca for 72 hours was almost entirely inhibited at concentration ... | 2005 | 17119614 |
| lateral transfer of the lux gene cluster. | the lux operon is an uncommon gene cluster. to find the pathway through which the operon has been transferred, we sequenced the operon and both flanking regions in four typical luminous species. in vibrio cholerae ncimb 41, a five-gene cluster, most genes of which were highly similar to orthologues present in gram-positive bacteria, along with the lux operon, is inserted between vc1560 and vc1563, on chromosome 1. because this entire five-gene cluster is present in photorhabdus luminescens tt01, ... | 2007 | 17169972 |
| 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 |