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At least 73 records · Page 4Linked to original sources
PubMed1993

Nucleotide sequence of the luxC gene encoding fatty acid reductase of the lux operon from Photobacterium leiognathi.

The nucleotide sequence of the luxC gene (EMBL Accession No. 65156) encoding fatty acid reductase (FAR) of the lux operon from Photobacterium leiognathi PL741 was determined and the encoded amino acid sequence deduced. The fatty acid reductase is a component of the fatty acid reductase complex. The complex is responsible for converting fatty acid to aldehyde which serves as the substrate in the luciferase-catalyzed bioluminescent reaction. The protein comprises 478 amino acid residues and has a calculated M(r) of 53,858. Alignment and comparison of the fatty acid reductase of P. leiognathi with that of Vibrio harveyi B392 and Vibrio fischeri ATCC 7744 shows that there is 70% and 59% amino acid residues identity, respectively.

Aldehyde Oxidoreductases↗
PubMed1995

Nucleotide sequence and functional analysis of regulatory region of the lumP and the lux operon from Photobacterium leiognathi.

The lumP gene is linked to the lux operon, but runs in the opposite direction in Photobacterium leiognathi PL741. The gene order of the lumP and the lux operon is < -lumP-R & R-luxC-luxD-luxA-luxB-luxN-luxE- > (R & R: regulatory region). The nucleotide sequence of the regulatory region (827-bp) between the lumP and the lux operon was determined. Sequence analysis illustrates that the regulatory region includes two divergent promoter systems, PR-promoter system for the lux operon (R-operon) and PL-promoter system for the lumP or lum operon (L-operon). Functional analysis of the regulatory region shows that the PR- and PL-promoter systems both are able to lead the gene expression. The deletion experiment result elicits that the PR- and PL-promoter are coordinatively and negatively regulated; the PR- and PL-promoter might be competing for recognition by RNA polymerase to initiate transcription. The fact of the LumP responsible for the spectral blue shift in P. leiognathi implied that the lumP gene closedly linked to the lux operon is for coordinative regulation with the lux operon. In addition, the glucose repression on the PR-promoter system shows that the expression of the lux operon is regulated by cAMP-CRP induction in E. coli.

Base Sequence↗
PubMed1995

The lumQ gene is linked to the lumP gene and the lux operon in Photobacterium leiognathi.

The nucleotide sequence of the designated lumQ gene (EMBL accession No. U35231) from Photobacterium leiognathi PL741 has been determined, and the encoded amino acid sequence is deduced. The LumQ protein has a calculated M(r) of 28,416 and comprises 248 amino acid residues. The lumQ gene is identified as the envY-like gene by significant similarity of the encoded protein with the EnvY and AdiY proteins of E. coli; there the envY gene encodes the porin thermoregulatory protein EnvY, and the adiY gene encodes the putative transcriptional regulator protein AdiY. It suggests that the lumQ gene of P. leiognathi is orthologous to the envY and adiY genes of E. coli. The function of the protein encoded by the lumQ gene from P. leiognathi is not really defined yet, it is likely to be the DNA-binding protein related to the araC and xylS family of transcriptional regulators. The lumQ and lumP genes form the lum operon which linked to the lux operon, but run in the opposite direction. The gene order of the lum and the lux operon is < -ter-lumQ-lumP-R&R-luxC-luxD-luxA-luxB- luxN-luxE- > (R&R: regulatory region; ter: transcriptional terminator); whereas the regulatory region (R&R) includes two promoter systems, PR-promoter for the lux operon and PL-promoter for the lum operon; ter is the transcriptional terminator of the lum operon.

Amino Acid Sequence↗
PubMed1996

Regulatory region with putA gene of proline dehydrogenase that links to the lum and the lux operons in Photobacterium leiognathi.

Nucleotide sequence of regulatory region (R & R) with putA gene (EMBL Accession No. U39227) from Photobacterium leiognathi PL741 has been determined, and the putA gene encoded amino acid sequence of proline dehydrogenase is deduced. Alignment and comparison of proline dehydrogenase of P. leiognathi with the proline dehydrogenase domain in the PutA protein of Escherichia coli and Salmonella typhimurium show that they are homologous. Nucleotide sequence reveals that regulatory region with the putA gene is linked to the lum and lux operons in genome; the gene order is <--putA--R & R(I)<--ter-lumQ-lumP-R & R-luxC-luxD-luxA-luxB-luxE--> (R & R: regulatory region; ter:transcriptional terminator), whereas the R & R is the regulatory region for the lum and the lux operons, ter is the transcriptional terminator for the lum operon, and R & R(I) apparently is the regulatory region for the putA and related genes. Nucleotide sequence analysis illustrates the specific inverted repeat (SIR), cAMP-CRP consensus sequence, canonical -10/-35 promoter, putative operator and Shine-Dalgarno (SD) sequence on the regulatory region R & R(I) for the putA and related genes; it suggests that the putA and related genes are simply linked to the lum and the lux operons in genome, the regulatory region R & R(I) is independent for the putA and related genes.

Amino Acid Sequence↗
PubMed1996

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 synthetase encoded by the luxE gene has a calculated M, 43,128 and comprises 373 amino acid residues. Alignment and comparison of acyl-protein synthetases from P. leiognathi, P. phosphoreum, Vibrio fischeri, V. harveyi and Xenorhabdus luminescens shows that they are homologous; there is 75.5% homologous (44.2% identity and 31.3% similarity) among these species. Functional analysis illustrates that the specific segment sequence lying before or in the luxE gene might from potential loops omega o omega e1, omega e2 as mRNA stability loop and/or for sub-regulation by alternative modulation in the lux operon. The gene order of the luxE gene in the lux and the lum operons is<--ter-lumQ-lumP-R&R-luxC-luxD-luxA-luxB -luxN-luxE-->(R&R: regulatory region; ter; transcriptional terminator), whereas the R&R is the regulatory region for the lum and the lux operons, and ter is the transcriptional terminator for the lum operon.

Acyltransferases↗
PubMed1997

The pkI gene encoding pyruvate kinase I links to the luxZ gene which enhances bioluminescence of the lux operon from Photobacterium leiognathi.

Partial 3'-end nucleotide sequence of the pkI gene (GenBank accession No. AF019143) from Photobacterium leiognathi ATCC 25521 has been determined, and the encoded pyruvate kinase I is deduced. Pyruvate kinase I is the key enzyme of glycolysis, which converts phosphoenol pyruvate to pyruvate. Alignment and comparison of pyruvate kinase Is from P. leiognathi, E. coli and Salmonella typhimurium show that they are homologous. Nucleotide sequence reveals that the pkI gene is linked to the luxZ gene that enhances bioluminescence of the lux operon from P. leiognathi. The gene order of the pkI and luxZ genes is-pk1-ter-->-R&R"-luxZ-ter"-->, whereas ter is transcriptional terminator for the pkI and related genes, and R&R" is the regulatory region and ter" is transcriptional terminator for the luxZ gene. It clearly elicits that the pkI gene and luxZ gene are divided to two operons. Functional analysis confirms that the potential hairpin loop omega T is the transcriptional terminator for the pkI and related genes. It infers that the pkI and related genes are simply linked to the luxZ gene in P. leiognathi genome.

Amino Acid Sequence↗
PubMed1998

Characteristics analysis of the luzA gene encoding chaperone from Photobacterium leiognathi related to bioluminescence.

Nucleotide sequence of the luzA gene (GenBank accession No. AF039303) from Photobacterium leiognathi ATCC 25521 (NCIMB 2193) has been determined, and the chaperone encoded by the luzA gene was deduced. The LuzA chaperone has a calculated M(r) 26,295 and comprises 230 amino acid residues; the hydrophobic alpha-helix N-terminal 21 amino acid residues MKKTIFALLFMSVFI SYPSFA is the leader peptide, therefore the matured LuzA chaperone has a calculated M(r) 23,871 and comprises 209 amino acid residues only. The periplasmic LuzA chaperone is the protein concerned with the protein folding, assembly and stability. The luzA gene and the related genes are closely linked to the sod gene, that encoding Cu/Zn superoxide dismutase enables to enhance bioluminescence of the lux operon; the gene order of the luzA gene and related genes is -ufo'-luzA-ufoI-ufoII-ter->-R&R'-sod-ufo-- >. In trans complementation bioluminoassays in vivo elicit that the LuzA chaperone might be not directly concerned with bioluminescence of the lux operon from P. leiognathi in E. coli, but might enable to stabilize the proteins related to bioluminescence. The unidentified ufoII gene closely linked to the luzA gene is able to enhance bioluminescence.

Amino Acid Sequence↗
PubMed1998

Characteristic analysis of the luxG gene encoding the probable flavin reductase that resides in the lux operon of Photobacterium leiognathi.

Nucleotide sequence of the luxG gene (GenBank Accession No. AF053227) from Photobacterium leiognathi PL741 has been determined, and the encoded probable flavin reductase is deduced. The probable flavin reductase encoded by the luxG gene has a calculated M(r) 26,544 and comprises 235 amino acid residues. The probable flavin reductase like the NAD(P)H-flavin reductase might catalyze the reduction of flavins. Alignment and comparison of the probable flavin reductases from P. leiognathi PL741, ATCC 25521, P. phosphoreum, Vibrio fischeri, and V. harveyi show that they are homologous; there is 66% homologous (29.4% identity and 36.6% similarity). Also, the probable flavin reductase is homologous to the NAD(P)H-flavin reductase; it is perceived that the probable flavin reductase and the NAD(P)H-flavin reductase could be enzyme isoforms encoded by two genes of a multigene family for differential response functions. Functional analysis illustrates that the specific segment sequence lay inside and behind the luxG gene might form the potential hairpin loops omega gI, omega gII, omega o, and omega oT as mRNA stability loop or/and as the attenuator-like loop or the dynamic terminator-like block for sub-regulation in the lux operon. The gene order of the luxG gene in the lux operon and the lum operon is <--ter-lumQ-lumP-R&R-luxC-luxD-luxA-luxB-+ ++luxN-luxE-luxG--> (R&R: regulatory region; ter: transcriptional terminator), whereas the R&R is the regulatory region for the lum operon and the lux operon, and ter is the transcriptional terminator for the lum operon.

Amino Acid Sequence↗
PubMed2001

Riboflavin synthesis genes ribE, ribB, ribH, ribA reside in the lux operon of Photobacterium leiognathi.

Nucleotide sequence of the riboflavin synthesis genes ribE, ribB, ribH, ribA (GenBank Accession No. AF364106) resided in the lux operon of Photobacterium leiognathi PL741 has been determined, and the amino acid sequences of riboflavin synthetase (RibE), DHBP synthetase (RibB), lumazine synthetase (RibH), GTP cyclohydrolase II (RibA) encoded by the riboflavin synthesis genes are deduced. Nucleotide sequence reveals that the ribE gene encodes the riboflavin synthetase responsible for converting lumazine to riboflavin, the ribB gene encodes the DHBP synthetase responsible for 3,4-dihydroxyl-2-butanone 4-phosphate synthesis, the ribH gene encodes the lumazine synthetase responsible for lumazine synthesis, and the ribA gene encodes the GTP cyclohydrolase II responsible for lumazine synthesis. Functional analysis illustrates that the specific segments lay behind the ribH and ribA genes might form potential loops Omega(oT) and Omega(TI)--Omega(TII); Omega(oT) is functioned as mRNA stability loop or/and for subregulation by alternative modulation, and Omega(TI)--Omega(TII) could be the transcriptional terminator of the lux operon. The gene order of the ribE, ribB, ribH, ribA genes resided in the lux operon and linked to the lum operon is <--ter*-lumQ-lumP-R&R-luxC-luxD-luxA-luxB-luxN-luxE-luxG-ribE-ribB-ribH-ribA-ter--> (R&R: regulatory region; ter: transcriptional terminator), whereas the R&R is the regulatory region for the lum and the lux operons, and ter and ter* are the transcriptional terminators for the lux and lum operons.

Amino Acid Sequence↗
PubMed2001

The Acute toxicity of alpha-branched phenylsulfonyl acetates in Photobacterium phosphoreum test.

The acute toxicity (15-min EC(50)) of 20 alpha-substituted phenylsulfonyl acetates was measured using the Microtox test with Photobacterium phosphoreum. On the basis of TLSER, quantitative structure-activity relationships (QSARs) were calculated for the inhibition of bioluminescence. With the parameters molecular volume (V(mc)), dipolarity/polarizability (pi*), and the covalent contribution to Lewis basicity (epsilon(b)), a squared correlation coefficient (r(2)(adj)) of 0.868 and standard error of 0.094 for log EC(50) were obtained. By introducing a structural indicator variable (I), the regressive quality was improved (correlation coefficient of 0.948 and standard error of 0.059); the descriptors V(mc), pi*, and the electrostatic basicity contribution (q(-)) were significant. -NO(2)-- and -SO(2)--groups are active centers of these compounds. The strong hydrogen bonding effects between the compound active centers and FMNH(2) play an important role in the greater toxicity of these chemicals.

Luminescent Measurements↗
PubMed2001

The gill is a major organ for antibody secreting cell production following direct immersion of sea bass (Dicentrarchus labrax, L.) in a Photobacterium damselae ssp. piscicida bacterin: an ontogenetic study.

Extremely high numbers of antibody secreting cells (ASC) were observed in the gills of sea bass fry immunised at three different age/sizes (initial weight of 0.1, 2 and 5 g) by direct immersion in a Photobacterium damselae spp. piscicida bacterin. The relatively low ASC production in the head kidney and spleen suggests that the systemic compartment was only slightly stimulated upon immersion vaccination. There was no response of corresponding magnitude in the gut as the one observed in the gills. A clear age effect was observed in the ASC response of the different groups, especially visible in the gills. Significantly higher numbers of specific ASC were observed in the gills of the two oldest groups (initial weight of 2 and 5 g) compared with the youngest fish (initial weight of 0.1 g), but the oldest groups were not significantly different from each other. Additionally, a more rapid response was observed with the ageing of the fish, with peak responses in all the organs at day 18, 16 and 8 post-immunisation in the smallest to largest fish, respectively. There was no evidence that direct immersion exposure to P. damselae ssp. piscicida at the earliest stages used in the present study (0.1 g) was tolerogenic. In the context of present knowledge, this study strongly supports the importance of the route of immunisation to locally stimulate ASC and the importance that the gills might have in specific responses.

Age Factors↗
PubMed2001

Kinetics of juvenile sea bass (Dicentrarchus labrax, L.) systemic and mucosal antibody secreting cell response to different antigens (Photobacterium damselae spp. piscicida, Vibrio anguillarum and DNP).

The ELISPOT assay was used to measure the number of specific antibody secreting cells (ASC) induced during the primary and secondary immune responses in the spleen, head kidney and gut of juvenile (5 g) sea bass (Dicentrarchus labrax) to bacterial (Vibrio anguillarum and Photobacterium damselae ssp. piscicida) and hapten dinitrophenyl-conjugated to keyhole limpet haemocyanin (DNP-KLH) antigens administered intraperitoneally. High variability among individuals was observed at each sampling day. All fish were bath vaccinated to V. anguillarum at an earlier stage (2 g) in the farm of origin prior to the development of the experiments, and therefore only secondary and tertiary responses were measured in the group immunised with this bacterium. Significant differences to the controls were observed in the primary responses of the head kidney and the spleen to P. damselae ssp. piscicida and DNP, respectively. Frequency analysis of the production of ASC suggests that significant responses in the gut might be masked by the high error variance. The peak of the primary response was observed 4 days earlier to DNP (18-20 days post-immunisation) and it was significantly higher than the response to P. damselae ssp. piscicida. Higher numbers of ASC were observed in the secondary responses of the head kidney and spleen, although they were not statistically significantly different from the primary levels, probably due to the high error variance as supported by the frequency analysis. Nevertheless, together with a faster response (peak at 7 days post-immunisation), the data suggest that memory formation had occurred. Additionally, the data suggest that some suppression of the secondary immune response in the gut might have occurred. The head kidney appears to produce the highest number of specific ASC of the organs tested. It appears that sea bass show a relatively fast but short duration antibody response.

Animals↗
PubMed1995

Structural refinement of the non-fluorescent flavoprotein from Photobacterium leiognathi at 1.60 A resolution.

The crystallographically-determined structure of the non-fluorescent flavoprotein (NFP) from Photobacterium leiognathi, a homolog of the bacterial luciferase subunits, has been refined to a conventional R-factor [formula: see text] of 0.175 using synchrotron data between 10.0 and 1.60 A resolution. The molecular structure is a homodimer of beta/alpha domains, the monomer having structural similarities to (beta alpha)8 barrel proteins. However, one beta-strand and three alpha-helices of a typical (beta alpha)8 domain are not present in the NFP structure. The refined structure of NFP consists of the 228 amino acid polypeptide, 191 water molecules, a sulfate ion, and two flavin mononucleotides (FMNs) each with a covalently-attached myristate (C14 fatty acid). Both flavin adducts are well-ordered and have exceptional electron density for both the FMN and the myristate moieties. Each flavin mononucleotide-myristate adduct is characterized by a stereospecific linkage (the S enantiomer) between C-6 of the flavin isoalloxazine ring and the C-3' atom of the fatty acyl chain. The stereospecific nature of this flavin-fatty acid linkage suggests that it is the result of an enzyme-catalyzed reaction, most likely the bioluminescence reaction itself. The myristate chains are buried from solvent in hydrophobic pockets in the interior of the protein. Four amino acid side-chains of the NFP polypeptide have been modeled with alternate conformations. Five of the protein's seven alpha-helices have classical C-capping boxes. NFP is dimeric and many of the extensive contacts at the dimer interface are mediated by hydrogen-bonded water molecules as well as by hydrophobic interactions. One of the myristate acyl chains sits between NFP monomers and contributes a significant portion of the hydrophobic interactions at the NFP dimer interface.

Crystallography↗
PubMed2001

Single mutations at the subunit interface modulate copper reactivity in Photobacterium leiognathi Cu,Zn superoxide dismutase.

The functional properties and X-ray structures of five mutant forms of Photobacterium leiognathi Cu,Zn superoxide dismutase carrying single mutations at residues located at the dimer association interface have been investigated. When compared to the wild-type enzyme, the three-dimensional structures of the mutants show structural perturbations limited to the proximity of the mutation sites and substantial identity of active site geometry. Nonetheless, the catalytic rates of all mutants, measured at neutral pH and low ionic strength by pulse radiolysis, are higher than that of the wild-type protein. Such enzymatic activity increase is paralleled by enhanced active site accessibility to external chelating agents, which, in the mutated enzyme, remove more readily the active site copper ion. It is concluded that mutations at the prokaryotic Cu,Zn superoxide dismutase subunit interface can transduce dynamical perturbation to the active site region, promoting substrate active site accessibility. Such long-range intramolecular communication effects have not been extensively described before within the Cu,Zn superoxide dismutase homology family.

Amino Acid Substitution↗
PubMed2000

Presence of phospholipase-D (dly) gene coding for damselysin production is not a pre-requisite for pathogenicity in Photobacterium damselae subsp. damselae.

The presence of the phospholipase-D (dly) gene as pre-requisite for virulence of Photobacterium damselae subsp. damselae for poikilotherm and homoiotherm animals was investigated in a total of 17 strains isolated from fish, shellfish, mammals and seawater. With this aim, we developed two PCR protocols. A simple PCR using primers flanking the almost complete dly gene, and a multiplex-PCR using two sets of primers directed to internal fragments of the dly and 16S rRNA genes. Only six of the 17 Ph. damselae subsp. damselae strains studied harboured the dly gene regardless of their haemolytic activity against sheep or rabbit erythrocytes as well as their virulence for mammals and marine fish. In fact, all strains but one were pathogenic for one or both animals, with LD(50)values ranging from 1x10(3)and 3x10(5)bacteria for turbot, and 2x10(6)and 8x10(7)cells for mice. The PCR results were corroborated in dot blot hybridization experiments employing a DNA probe directed to an internal region of the dly gene. From the data obtained in this work, we can conclude that the presence of the dly gene is not an indicative of the pathogenicity of Ph. damselae subsp. damselae and, therefore, the role of damselysin as the main virulence factor of this marine bacterium for poikilotherm and homoiotherm hosts should be re-evaluated.

Animals↗
PubMed1989

Time-resolved fluorescence spectroscopy of lumazine protein from Photobacterium phosphoreum using synchrotron radiation.

Time-resolved fluorescence on lumazine protein from Photobacterium phosphoreum was performed with synchrotron radiation as a source of continuously tunable excitation. The experiments yielded structural and dynamic details from which two aspects became apparent. From fluorescence anisotropy decay monitoring of lumazine fluorescence with different excitation wavelengths, the average correlation times were shown to change, which must indicate the presence of anistropic motion of the protein. A similar study with 7-oxolumazine as the fluorescent ligand led to comparable results. The other remarkable observation dealt with the buildup of acceptor fluorescence, also observed with 7-oxolumazine although much less pronounced, which is caused by the finite energy transfer process between the single donor tryptophan and the energy accepting lumazine derivatives. Global analytical approaches in data analysis were used to yield realistic correlation times and reciprocal transfer rate constants. It was found that the tryptophan residue has a large motional freedom as also reported previously for this protein and for the related protein from P. leiognathi (Lee et al. 1985; Kulinski et al. 1987). The average distance between the tryptophan residue and the ligand donor-acceptor couple has been determined to be 2.7 nm for the same donor and two different acceptors.

Bacterial Proteins↗
PubMed1994

Genetic characterization of ompH mutants in the deep-sea bacterium Photobacterium sp. strain SS9.

OmpH is an outer membrane protein produced by the deep-sea bacterium Photobacterium species strain SS9 in response to elevated hydrostatic pressure. In order to facilitate studies of the function of this protein, a series of OmpH+ and OmpH- strains were obtained from SS9 by Tn5 gene replacement mutagenesis. A previously isolated ompH::lacZ strain and a derivative of this strain harboring a plasmid expressing the wild-type ompH gene were also utilized. The acridine mutagen ICR 191 preferentially inhibited the growth of OmpH+ over OmpH- cells. Indeed, OmpH+ cultures treated with the mutagen rapidly accumulated mutants producing reduced levels of OmpH. In addition, OmpH+ cells took up the peptide Met-Leu-Phe approximately 15 times more rapidly than OmpH- cells. The results are consistent with the hypothesis that OmpH functions as a relatively large, nonspecific diffusion channel.

Aminacrine↗
PubMed1975

Enzymes of D-fructose catabolism in species of Beneckea and Photobacterium.

Cell-free extracts of strains representative of the genera Beneckea and Photobacterium catalyzed a P-enolpyruvate dependent phosphorylation of D-fructose. The resulting product, fructose-1-P, was converted to fructose-1,6-P2 by 1-P-fructokinase. Both activities were inducible, being present in D-fructose-grown cells and reduced or absent in D-gluconate-(or succinate-) grown cells.

Adenosine Triphosphate↗