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Journal of Fish Diseases May 2009A selection of 16 field isolates of Photobacterium damselae from marine rainbow trout farms in Denmark was subjected to phenotypic and genotypic characterization and...
A selection of 16 field isolates of Photobacterium damselae from marine rainbow trout farms in Denmark was subjected to phenotypic and genotypic characterization and pathogenicity to fish. All isolates belonged to the subspecies damselae, being positive for haemolysis, motility and urease. There were considerable differences in haemolytic properties, some isolates presenting a broad zone of haemolysis and others only a narrow zone. Pulsed-field gel electrophoresis revealed a high diversity indicating that P. damselae subsp. damselae is an opportunistic, not clonal pathogen in Danish marine rainbow trout. Virulence of the strains to rainbow trout was highly variable with LD(50) values ranging from 3.9 x 10(3) to 1.5 x 10(8) cfu at 20 degrees C. The virulence was significantly higher at 20 degrees C than at 13 degrees C. The strains with the strongest haemolytic properties were the most virulent suggesting a strong involvement of haemolysin in the pathogenesis. The pathological changes were consistent with a bacterial septicaemia and the haemorrhages were more pronounced than for most other bacterial infections.
Topics: Animals; Anti-Infective Agents; Communicable Diseases, Emerging; Denmark; Fish Diseases; Fisheries; Gram-Negative Bacterial Infections; Oncorhynchus mykiss; Photobacterium; Phylogeny
PubMed: 19364386
DOI: 10.1111/j.1365-2761.2009.01041.x -
Diseases of Aquatic Organisms Apr 2002A PCR protocol for the rapid diagnosis of fish 'pasteurellosis' based on 16S rRNA gene sequences was developed. The procedure combines low annealing temperature that...
Photobacterium damselae ssp. piscicida: detection by direct amplification of 16S rRNA gene sequences and genotypic variation as determined by amplified fragment length polymorphism (AFLP).
A PCR protocol for the rapid diagnosis of fish 'pasteurellosis' based on 16S rRNA gene sequences was developed. The procedure combines low annealing temperature that detects low titers of Photobacterium damselae but also related species, and high annealing temperature for the specific identification of P. damselae directly from infected fish. The PCR protocol was validated on 19 piscine isolates of P. damselae ssp. piscicida from different geographic regions (Japan, Italy, Spain, Greece and Israel), on spontaneously infected sea bream Sparus aurata and sea bass Dicentrarchus labrax, and on closely related American Type Culture Collection (ATCC) reference strains. PCR using high annealing temperature (64 degrees C) discriminated between P. damselae and closely related reference strains, including P. histaminum. Sixteen isolates of P. damselae ssp. piscicida, 2 P. damselae ssp. piscicida reference strains and 1 P. damselae ssp. damselae reference strain were subjected to Amplified Fragment Length Polymorphism (AFLP) analysis, and a similarity matrix was produced. Accordingly, the Japanese isolates of P. damselae ssp. piscicida were distinguished from the Mediterranean/European isolates at a cut-off value of 83% similarity. A further subclustering at a cut-off value of 97% allowed discrimination between the Israeli P. damselae ssp. piscicida isolates and the other Mediterranean/European isolates. The combination of PCR direct amplification and AFLP provides a 2-step procedure, where P. damselae is rapidly identified at genus level on the basis of its 16S rRNA gene sequence and then grouped into distinct clusters on the basis of AFLP polymorphisms. The first step of direct amplification is highly sensitive and has immediate practical consequences, offering fish farmers a rapid diagnosis, while the AFLP is more specific and detects intraspecific variation which, in our study, also reflected geographic correspondence. Because of its superior discriminative properties, AFLP can be an important tool for epidemiological and taxonomic studies of this highly homogeneous genus.
Topics: Animals; Bass; DNA, Bacterial; Fish Diseases; Gene Amplification; Genetic Variation; Genotype; Gram-Negative Bacterial Infections; Photobacterium; Polymerase Chain Reaction; Polymorphism, Restriction Fragment Length; RNA, Ribosomal, 16S; Sea Bream; Sensitivity and Specificity; Species Specificity
PubMed: 12033705
DOI: 10.3354/dao048187 -
Systematic and Applied Microbiology Sep 2018Three strains, H01100409B, H01100413B, and H27100402H, were isolated from several internal organs of diseased redbanded seabream (Pagrus auriga) reared in Andalusia...
Three strains, H01100409B, H01100413B, and H27100402H, were isolated from several internal organs of diseased redbanded seabream (Pagrus auriga) reared in Andalusia (Southern Spain). All strains were studied by phenotypic, including chemotaxonomy, and genomic characteristics. Phylogenetic analysis based on concatenated sequences of six housekeeping genes (gyrB, ftsZ, topA, mreB, gapA, and 16S rRNA) supported the inclusion of the strains within the clade Phosphoreum of the genus Photobacterium, and two of the strains (H27100402H and H01100409B) formed a tight group separated from the closest species P. aquimaris. Genomic analyses, including average nucleotide identity (ANIb and ANIm) and DNA-DNA hybridization (DDH), clearly separated strains H27100402H and H01100409B from the other species within the clade Phosphoreum with values below the thresholds for species delineation. The chemotaxonomic features (including FAME analysis and MALDI-TOF-MS) of H27100402H and H01100409B strains confirmed their differentiation from the related taxa. The results demonstrated that strain H01100413B was classified as P. aquimaris and the strains H27100402H and H01100409B represented a new species each in the genus Photobacterium, for which we propose the names Photobacterium malacitanum sp. nov., type strain H27100402H (=CECT 9190=LMG 29992), and Photobacterium andalusiense sp. nov., type strain H01100409B (=CECT 9192=LMG 29994).
Topics: Animals; Base Composition; DNA, Bacterial; Fish Diseases; Fisheries; Genes, Bacterial; Genome, Bacterial; Phenotype; Photobacterium; Phylogeny; RNA, Ribosomal, 16S; Sequence Analysis, DNA; Spain; Species Specificity; Vitamin K 2
PubMed: 29804705
DOI: 10.1016/j.syapm.2018.04.005 -
Antonie Van Leeuwenhoek Jan 1990A Photobacterium-like bacterium isolated from the roots of eelgrass (Zostera marina) was shown to fix nitrogen under anaerobic conditions. Nitrogen fixation by...
A Photobacterium-like bacterium isolated from the roots of eelgrass (Zostera marina) was shown to fix nitrogen under anaerobic conditions. Nitrogen fixation by Photobacterium spp. has not been reported previous to this.
Topics: Culture Media; Nitrogen Fixation; Photobacterium; Plants
PubMed: 2372212
DOI: 10.1007/BF00400336 -
Journal of Fish Diseases Jul 2020Photobacteriosis, caused by Photobacterium damselae subsp. piscicida (Phdp), is a serious disease in marine fish species worldwide. To date, the epidemiological...
Photobacteriosis, caused by Photobacterium damselae subsp. piscicida (Phdp), is a serious disease in marine fish species worldwide. To date, the epidemiological characterization of this pathogen in Taiwan remains limited. In this study, we collected 39 Phdp isolates obtained from different farmed fish for phenotypic and genotypic analysis. Phenotype bioassays using API-20E and API-20NE systems showed that the Phdp is a homogeneous group. However, genotyping using the pulsed-field gel electrophoresis (PFGE) technique revealed genetic variability among Phdp isolates when 13 and 11 different PFGE band patterns were obtained with SmaI and NotI as restriction enzymes, respectively. Phylogenetic analysis using 16S rDNA and the Fur gene clustered Taiwanese isolates and other species of P. damselae in the same clade. In contrast, the ToxR phylogenetic tree, a powerful discriminatory marker, separated the two subspecies. Furthermore, the virulence-associated genes, AIP56, P55, PDP_0080, Sod and Irp1, were detected from all isolates. Virulence testing with nine representative isolates in cobia (Rachycentron canadum) and Asian sea bass (Lates calcarifer) showed that some were highly pathogenic with 80%-100% mortality rates. This study provides epidemiological data of Phdp infections in farmed fish in Taiwan, which is necessary to develop comprehensive prevention and control strategies for the disease.
Topics: Animals; Fish Diseases; Fishes; Genetic Variation; Genotype; Gram-Negative Bacterial Infections; Phenotype; Photobacterium; Phylogeny; Taiwan; Virulence
PubMed: 32419196
DOI: 10.1111/jfd.13173 -
Extremophiles : Life Under Extreme... Dec 2002The identity and amounts of intracellular solutes in the deep-sea bacterium Photobacterium profundum strain SS9 were studied using nuclear magnetic resonance techniques....
The identity and amounts of intracellular solutes in the deep-sea bacterium Photobacterium profundum strain SS9 were studied using nuclear magnetic resonance techniques. P. profundum strain SS9, a moderate piezophile which grows optimally at 20-30 MPa primarily accumulated glutamate and betaine, with lesser amounts of alanine, beta-hydroxybutyrate (beta-HB) and oligomers composed of the beta-HB units when grown at 0.1 MPa to early stationary phase. When grown at the optimal pressure, the cells preferentially increased intracellular concentrations of beta-HB and beta-HB oligomers, while the amino acid pools remained relatively constant. Since the organic solutes increased with increasing external NaCl in the medium, they are functioning as osmolytes. The beta-HB molecules represent a novel class of osmolytes, termed 'piezolytes,' whose cellular levels responded to hydrostatic pressure as well as osmotic pressure. Factors such as cell growth stage and temperature were also examined for their effect on the solute distribution in these cells.
Topics: 3-Hydroxybutyric Acid; Adaptation, Physiological; Alanine; Betaine; Biological Transport; Glutamic Acid; Hydrostatic Pressure; Intracellular Fluid; Models, Biological; Nuclear Magnetic Resonance, Biomolecular; Photobacterium; Saline Solution, Hypertonic; Temperature; Water Microbiology; Water-Electrolyte Balance
PubMed: 12486460
DOI: 10.1007/s00792-002-0288-1 -
International Journal of Food... Dec 2020While the abundance of photobacteria has previously been exclusively associated with marine environments and spoilage of seafood, several recent studies have...
While the abundance of photobacteria has previously been exclusively associated with marine environments and spoilage of seafood, several recent studies have demonstrated their status as pervasive constituents of the microbiota on packaged meats. Since their ubiquitous nature has been revealed, detection of their presence on meat, their entry route into meat processing environments and prevention of their growth is a novel emerging challenge for the food industry. In this study, we have developed a highly sensitive and specific loop-mediated isothermal amplification (LAMP) assay for the detection of relevant species of photobacteria on foods, and tested its efficacy on meats. The gene encoding trimethylamine-N-oxide reductase (torA) was chosen as the target for this assay. Designed primers based on the gene sequence proved their specificity by testing 67 isolates of 5 species of photobacteria (positive) as well as 63 strains of 16 species of other common meat spoilers (negative). The optimized assay takes 2 h including sample preparation and has a detection limit of only 10-11 copies (50 fg/reaction) of the average Photobacterium (P.) genome per reaction. Its applicability could be successfully demonstrated on naturally and artificially contaminated chicken, beef and pork samples and evaluated by comparison with a culture-dependent approach using selective media and MALDI-TOF MS for identification. The developed LAMP assay revealed presence of photobacteria on one naturally contaminated chicken sample stored at 4 °C long before (3 days) confirmation by the culture-dependent approach. This study demonstrates that the developed LAMP assay represents a reliable and sensitive method for rapid detection of photobacteria on meats. However, its specificity would allow the applicability of the methodology to be extended to other foods, e.g. fish and seafood where presence of photobacteria is directly linked to their shelf life. The method has no requirement for specialized equipment or specially trained personal allowing an easy implementation within the quality control of the food industry. Considering the lot-to-lot variations observed on meats regarding the presence of photobacteria and the impracticality of implementing quantitative methods within the routine control, the LAMP method can simplify and reduce the workload for detection of photobacteria on high sample numbers. Consequently, producers can identify batches/plants that need more stringent control, and are provided with a tool to determine the entry route of photobacteria into the processing and distribution chain of raw meats.
Topics: Animals; Cattle; Chickens; Food Microbiology; Limit of Detection; Meat; Molecular Diagnostic Techniques; Nucleic Acid Amplification Techniques; Oxidoreductases, N-Demethylating; Photobacterium
PubMed: 32799119
DOI: 10.1016/j.ijfoodmicro.2020.108805 -
Antonie Van Leeuwenhoek May 2015Photobacterium species are ubiquitous in the aquatic environment and can be found in association with animal hosts including pathogenic and mutualistic associations. The...
Photobacterium species are ubiquitous in the aquatic environment and can be found in association with animal hosts including pathogenic and mutualistic associations. The traditional phenotypic characterization of Photobacterium is expensive, time-consuming and restricted to a limited number of features. An alternative is to infer phenotypic information directly from whole genome sequences. The present study evaluates the usefulness of whole genome sequences as a source of phenotypic information and compares diagnostic phenotypes of the Photobacterium species from the literature with the predicted phenotypes obtained from whole genome sequences. All genes coding for the specific proteins involved in metabolic pathways responsible for positive phenotypes of the seventeen diagnostic features were found in the majority of the Photobacterium genomes. In the Photobacterium species that were negative for a given phenotype, at least one or several genes involved in the respective biochemical pathways were absent.
Topics: Bacterial Typing Techniques; Base Sequence; Genome, Bacterial; Molecular Sequence Data; Phenotype; Photobacterium; Phylogeny
PubMed: 25724129
DOI: 10.1007/s10482-015-0414-6 -
International Journal of Molecular... Sep 2021Detecting the folding/unfolding pathways of biological macromolecules is one of the urgent problems of molecular biophysics. The unfolding of bacterial luciferase from...
Detecting the folding/unfolding pathways of biological macromolecules is one of the urgent problems of molecular biophysics. The unfolding of bacterial luciferase from is well-studied, unlike that of , despite the fact that both of them are actively used as a reporter system. The aim of this study was to compare the conformational transitions of these luciferases from two different protein subfamilies during equilibrium unfolding with urea. Intrinsic steady-state and time-resolved fluorescence spectra and circular dichroism spectra were used to determine the stages of the protein unfolding. Molecular dynamics methods were applied to find the differences in the surroundings of tryptophans in both luciferases. We found that the unfolding pathway is the same for the studied luciferases. However, the results obtained indicate more stable tertiary and secondary structures of luciferase as compared to enzyme from during the last stage of denaturation, including the unfolding of individual subunits. The distinctions in fluorescence of the two proteins are associated with differences in the structure of the C-terminal domain of α-subunits, which causes different quenching of tryptophan emissions. The time-resolved fluorescence technique proved to be a more effective method for studying protein unfolding than steady-state methods.
Topics: Luciferases, Bacterial; Molecular Dynamics Simulation; Photobacterium; Protein Domains; Spectrometry, Fluorescence; Vibrio
PubMed: 34638798
DOI: 10.3390/ijms221910449 -
Extremophiles : Life Under Extreme... Aug 1997Many microorganisms from the deep-sea display high-pressure-adapted--also described as barophilic or piezophilic--growth characteristics. Phylogenetic studies have... (Review)
Review
Many microorganisms from the deep-sea display high-pressure-adapted--also described as barophilic or piezophilic--growth characteristics. Phylogenetic studies have revealed that a large proportion of the barophilic bacteria currently in culture collections belong to a distinct subgroup of the genus Shewanella, referred to as the "barophile branch." Many of the basic properties of barophiles that enable their survival at extremes of pressure remain to be elucidated. However, several genes whose expression is regulated by pressure, or which appear to be critical to baroadaptation, have been uncovered. One such operon, whose presence appears to be restricted to the "barophile branch," has been identified in DNA samples obtained from sediments recovered in the deepest ocean trench. In the case of another set of pressure-regulated genes, regulatory elements required for pressure signaling have been uncovered. The nature and regulation of these genes is discussed.
Topics: Genes, Bacterial; Gram-Negative Bacteria; Oceans and Seas; Photobacterium; Phylogeny; Pressure; Water Microbiology
PubMed: 9680316
DOI: 10.1007/s007920050023