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International Journal of Systematic and... Feb 2014A Gram-staining-negative, motile, weakly halophilic and facultatively aerobic bacterium, designated strain YA11(T), was isolated from tidal flat sediment at Yeongam Bay,...
A Gram-staining-negative, motile, weakly halophilic and facultatively aerobic bacterium, designated strain YA11(T), was isolated from tidal flat sediment at Yeongam Bay, South Korea. Strain YA11(T) grew at 10-30 °C (optimum, 20 °C), at pH 6.0-10.0 (optimum, pH 6.5-7.5) and in the presence of 1-6% (w/v) NaCl (optimum, 2-3%). The major cellular fatty acids of the strain were summed feature 3 (C(16 : 1)ω7c and/or C(16 : 1)ω6c), summed feature 8 (C(18 : 1)ω7c and/or C(18 : 1)ω6c) and C(16 : 0). The DNA G+C content of the genomic DNA was 44.2 mol%. Strain YA11(T) contained Q-8 as the sole respiratory quinone. A phylogenetic tree based on 16S rRNA gene sequences showed that strain YA11(T) formed a distinct phyletic lineage within the genus Photobacterium and the 16S rRNA gene sequence similarities between strain YA11(T) and the type strains of species of the genus Photobacterium ranged between 94.0 and 96.4%. Based on the phenotypic, chemotaxonomic and molecular properties, strain YA11(T) represents a novel species of the genus Photobacterium, for which the name Photobacterium aestuarii sp. nov. is proposed, with strain YA11(T)( = KACC 16912(T) = JCM 18592(T)) as the type strain.
Topics: Bacterial Typing Techniques; Base Composition; Bays; DNA, Bacterial; Fatty Acids; Geologic Sediments; Molecular Sequence Data; Photobacterium; Phylogeny; RNA, Ribosomal, 16S; Republic of Korea; Seawater; Sequence Analysis, DNA; Ubiquinone
PubMed: 24158952
DOI: 10.1099/ijs.0.056861-0 -
PloS One 2014Photobacterium profundum is a cosmopolitan marine bacterium capable of growth at low temperature and high hydrostatic pressure. Multiple strains of P. profundum have...
Photobacterium profundum is a cosmopolitan marine bacterium capable of growth at low temperature and high hydrostatic pressure. Multiple strains of P. profundum have been isolated from different depths of the ocean and display remarkable differences in their physiological responses to pressure. The genome sequence of the deep-sea piezopsychrophilic strain Photobacterium profundum SS9 has provided some clues regarding the genetic features required for growth in the deep sea. The sequenced genome of Photobacterium profundum strain 3TCK, a non-piezophilic strain isolated from a shallow-water environment, is now available and its analysis expands the identification of unique genomic features that correlate to environmental differences and define the Hutchinsonian niche of each strain. These differences range from variations in gene content to specific gene sequences under positive selection. Genome plasticity between Photobacterium bathytypes was investigated when strain 3TCK-specific genes involved in photorepair were introduced to SS9, demonstrating that horizontal gene transfer can provide a mechanism for rapid colonisation of new environments.
Topics: Ecotype; Gene Expression Regulation, Bacterial; Genetic Variation; Genome, Bacterial; Photobacterium
PubMed: 24824441
DOI: 10.1371/journal.pone.0096953 -
Applied and Environmental Microbiology Jan 2016Scombrotoxin fish poisoning (SFP) remains the main contributor of fish poisoning incidents in the United States, despite efforts to control its spread. Psychrotrophic...
Scombrotoxin fish poisoning (SFP) remains the main contributor of fish poisoning incidents in the United States, despite efforts to control its spread. Psychrotrophic histamine-producing bacteria (HPB) indigenous to scombrotoxin-forming fish may contribute to the incidence of SFP. We examined the gills, skin, and anal vents of yellowfin (n = 3), skipjack (n = 1), and albacore (n = 6) tuna for the presence of indigenous HPB. Thirteen HPB strains were isolated from the anal vent samples from albacore (n = 3) and yellowfin (n = 2) tuna. Four of these isolates were identified as Photobacterium kishitanii and nine isolates as Photobacterium angustum; these isolates produced 560 to 603 and 1,582 to 2,338 ppm histamine in marine broth containing 1% histidine (25°C for 48 h), respectively. The optimum growth temperatures and salt concentrations were 26 to 27°C and 1% salt for P. kishitanii and 30 to 32°C and 2% salt for P. angustum in Luria 70% seawater (LSW-70). The optimum activity of the HDC enzyme was at 15 to 30°C for both species. At 5°C, P. kishitanii and P. angustum had growth rates of 0.1 and 0.2 h(-1), respectively, and the activities of histidine decarboxylase (HDC) enzymes were 71% and 63%, respectively. These results show that indigenous HPB in tuna are capable of growing at elevated and refrigeration temperatures. These findings demonstrate the need to examine the relationships between the rate of histamine production at refrigeration temperatures, seafood shelf life, and regulatory limits.
Topics: Animals; Bacterial Proteins; Food Contamination; Foodborne Diseases; Histamine; Histidine Decarboxylase; Marine Toxins; Photobacterium; Phylogeny; Seafood; Tuna
PubMed: 26826233
DOI: 10.1128/AEM.02833-15 -
International Journal of Systematic and... Jan 2005A Gram-negative, motile, non-spore-forming, pleomorphic and lipolytic bacterial strain, M37T, was isolated from an intertidal sediment of the Yellow Sea in Korea. This...
A Gram-negative, motile, non-spore-forming, pleomorphic and lipolytic bacterial strain, M37T, was isolated from an intertidal sediment of the Yellow Sea in Korea. This organism grew optimally at 25-28 degrees C and in the presence of 1-2 % NaCl. It did not grow without NaCl or in the presence of more than 6 % NaCl. Strain M37T was characterized chemotaxonomically by having Q-8 as the predominant respiratory lipoquinone and C(16 : 1)omega7c and/or iso-C(15 : 0) 2-OH and C(16 : 0) as the major fatty acids. The DNA G+C content was 47 mol%. Phylogenetic analyses based on 16S rRNA gene sequences placed strain M37T within the clade comprising Photobacterium species, forming a coherent cluster with the type strains of Photobacterium profundum and Photobacterium indicum (16S rRNA gene similarity levels of 97.5-98.0 %). The mean DNA-DNA relatedness levels between strain M37T and P. profundum JCM 10084T and P. indicum DSM 5151T were in the range 12-15 %. Similarities between 16S rRNA gene sequences of strain M37T and those of the type strains of the other Photobacterium species ranged from 93.9 % (with Photobacterium fischeri) to 96.2 % (with Photobacterium phosphoreum). On the basis of phenotypic properties and phylogenetic and genomic distinctiveness, strain M37T (=KCTC 10562BPT=DSM 16190T) should be placed in the genus Photobacterium as a novel species, for which the name Photobacterium lipolyticum sp. nov. is proposed.
Topics: Bacterial Typing Techniques; Base Composition; DNA, Bacterial; DNA, Ribosomal; Genes, rRNA; Geologic Sediments; Korea; Lipase; Molecular Sequence Data; Phenotype; Photobacterium; Phylogeny; RNA, Ribosomal, 16S; Seawater; Sequence Analysis, DNA
PubMed: 15653897
DOI: 10.1099/ijs.0.63215-0 -
Food Microbiology Oct 2021Photobacterium spp. occur frequently in marine environments but have been recently also found as common spoilers on chilled meats. The environmental conditions in these...
Photobacterium spp. occur frequently in marine environments but have been recently also found as common spoilers on chilled meats. The environmental conditions in these ecological niches differ especially regarding salinity and ambient pressure. Linking the occurrence of photobacteria in different niches may elucidate its ecology and bring insights for the food industry. We investigated tolerance of Photobacterium (P.) phosphoreum and P. carnosum strains to high hydrostatic pressure and salinity and aligned our observations with presence of relevant genes. The strains were isolated from packaged meats and salmon (or the sea) to identify adaptations to marine and terrestrial habitats. Growth of all P. carnosum strains was reduced by 40 MPa hydrostatic pressure and >3% sodium chloride, suggesting loss of traits associated with marine habitats. In contrast, P. phosphoreum strains were only slightly affected, suggesting general adaptation to marine habitats. In accordance, these strains had gene clusters associated with marine niches, e.g. flagellar and lux-operons, being incomplete in P. carnosum. Occurrence of P. carnosum strains on packaged salmon and P. phosphoreum strains on meats therefore likely results from cross-contamination in meat and fish processing. Still, these strains showed intermediate traits regarding pressure- and halotolerance, suggesting developing adaptation to their respective environment.
Topics: Animals; Cattle; Chickens; Food Microbiology; Hydrostatic Pressure; Meat; Photobacterium; Salmon; Seawater; Sodium Chloride
PubMed: 34119089
DOI: 10.1016/j.fm.2020.103679 -
Journal of Food Protection Aug 2018Photobacterium species are members of the bacterial communities typically associated with scombrotoxin-forming fish. Reclassification and discovery of new Photobacterium...
Photobacterium species are members of the bacterial communities typically associated with scombrotoxin-forming fish. Reclassification and discovery of new Photobacterium species has caused confusion as to which species are capable of biogenic amine production. We analyzed histamine, cadaverine, and putrescine production by 104 Photobacterium strains representing 23 species. The presence of the genes for histidine decarboxylase ( hdc), lysine decarboxylase ( ldc), and ornithine decarboxylase ( odc) was determined by real-time or conventional PCR and whole genome sequencing. Significant histamine production (>200 ppm) was detected in five Photobacterium species: P. angustum, P. aquimaris, P. kishitanii, P. damselae, and P. phosphoreum. The hdc gene was detected in all of these histamine-producing species except P. phosphoreum. Cadaverine was produced by eight Photobacterium species: P. angustum, P. aquimaris, P. damselae, P. iliopiscarium, P. kishitanii, P. leiognathi, P. mandapamensis, and P. phosphoreum. Putrescine was produced by six Photobacterium species: P. angustum, P. aquimaris, P. kishitanii, P. leiognathi, P. mandapamensis, and Photobacterium sp. Cadaverine production correlated closely with the presence of the ldc gene, but putrescine production did not correlate closely with the presence of the odc gene. Characterization of the biogenic amine production by Photobacterium species will allow identification of these marine bacteria and help ensure that current guidelines account for mitigation of these bacteria.
Topics: Animals; Biogenic Amines; Carboxy-Lyases; Consumer Product Safety; Fishes; Food Contamination; Histidine Decarboxylase; Ornithine Decarboxylase; Photobacterium; Phylogeny; Sequence Analysis, DNA
PubMed: 29985067
DOI: 10.4315/0362-028X.JFP-18-022 -
Applied and Environmental Microbiology Jul 2016Photobacterium damselae subsp. damselae is considered to be an emerging pathogen of marine fish of importance in aquaculture, with a notable increase in its geographical...
UNLABELLED
Photobacterium damselae subsp. damselae is considered to be an emerging pathogen of marine fish of importance in aquaculture, with a notable increase in its geographical distribution during the last several years. In this study, we carried out for the first time to our knowledge a genetic and pathobiological characterization of 14 strains isolated from sea bass (Dicentrarchus labrax) reared in the Southeastern Black Sea, where high mortalities were observed at two aquaculture farms during the summer and autumn of 2011. Heterogeneity was evidenced among strains in phenotypical traits, such as sucrose fermentation, motility, and hemolysis. Although 11 of 14 isolates were hemolytic, we found that all of the isolates lacked the pPHDD1 virulence plasmid that encodes the phospholipase-D damselysin (Dly) and the pore-forming toxin PhlyP, two hemolysins previously reported to constitute major virulence factors for turbot. Subsequent PCR and sequencing analyses demonstrated that the 11 hemolytic isolates harbored a complete hlyAch gene, a chromosome I-borne gene that encodes HlyAch hemolysin, whereas the three nonhemolytic isolates contained hlyAch pseudogenes caused by insertion sequence elements. Virulence challenges with two representative strains revealed that, albeit less virulent than the pPHDD1-harboring strain RM-71, the plasmidless hlyAch-positive and hlyAch-negative Black Sea isolates were pathogenic for sea bass. A phylogenetic analysis based on the toxR gene sequence uncovered a greater diversity in the isolates, indicating that the presence of this pathogen in the Black Sea was not caused by the introduction and spread of a single virulent clone but by the proliferation of different clones.
IMPORTANCE
The geographical distribution of marine bacterial pathogens is undergoing a worldwide increase. In particular, bacteria of the group vibrios are increasingly being isolated as the causative agents of disease in novel species of cultivated fish in areas where they had not been previously reported. Here we characterize for the first time to our knowledge a collection of isolates of the fish and human pathogen Photobacterium damselae subsp. damselae from diseased sea bass reared in the Black Sea. We uncovered great genetic diversity in the Black Sea isolates of this pathogen, suggesting a multiclonal origin. We also demonstrate for the first time that these isolates bear pathogenic potential for sea bass cultures by virulence challenges.
Topics: Animals; Aquaculture; Bacterial Typing Techniques; Bass; Black Sea; Fish Diseases; Genes, Bacterial; Genetic Variation; Genotype; Gram-Negative Bacterial Infections; Photobacterium; Polymerase Chain Reaction; Sequence Analysis, DNA; Virulence Factors
PubMed: 27084008
DOI: 10.1128/AEM.00781-16 -
Journal of Bacteriology Dec 2015Bacterial bioluminescence is taxonomically restricted to certain proteobacteria, many of which belong to the Vibrionaceae. In the most well-studied cases, pheromone...
UNLABELLED
Bacterial bioluminescence is taxonomically restricted to certain proteobacteria, many of which belong to the Vibrionaceae. In the most well-studied cases, pheromone signaling plays a key role in regulation of light production. However, previous reports have indicated that certain Photobacterium strains do not use this regulatory method for controlling luminescence. In this study, we combined genome sequencing with genetic approaches to characterize the regulation of luminescence in Photobacterium leiognathi strain KNH6, an extremely bright isolate. Using transposon mutagenesis and screening for decreased luminescence, we identified insertions in genes encoding components necessary for the luciferase reaction (lux, lum, and rib operons) as well as in nine other loci. These additional loci encode gene products predicted to be involved in the tricarboxylic acid (TCA) cycle, DNA and RNA metabolism, transcriptional regulation, and the synthesis of cytochrome c, peptidoglycan, and fatty acids. The mutagenesis screen did not identify any mutants with disruptions of predicted pheromone-related loci. Using targeted gene insertional disruptions, we demonstrate that under the growth conditions tested, luminescence levels do not appear to be controlled through canonical pheromone signaling systems in this strain.
IMPORTANCE
Despite the long-standing interest in luminous bacteria, outside a few model organisms, little is known about the regulation and function of luminescence. Light-producing marine bacteria are widely distributed and have diverse lifestyles, suggesting that the control and significance of luminescence may be similarly diverse. In this study, we apply genetic tools to the study of regulation of light production in the extremely bright isolate Photobacterium leiognathi KNH6. Our results suggest an unusual lack of canonical pheromone-mediated control of luminescence and contribute to a better understanding of alternative strategies for regulation of a key bacterial behavior. These experiments lay the groundwork for further study of the regulation and role of bioluminescence in P. leiognathi.
Topics: Bacterial Proteins; Gene Expression Regulation, Bacterial; Luciferases; Luminescence; Molecular Sequence Data; Mutagenesis, Insertional; Operon; Photobacterium
PubMed: 26350139
DOI: 10.1128/JB.00524-15 -
Microbiological Research Mar 2020Photobacterium species are widely distributed in the marine environment. The overall metabolism of this genus remains largely unknown. In order to improve our knowledge...
Photobacterium species are widely distributed in the marine environment. The overall metabolism of this genus remains largely unknown. In order to improve our knowledge on this bacterium, the relationship between the genome and phenome of the Photobacterium isolate was analyzed. The cream colored, Gram-negative, rod-shaped and motile bacterial strain, J15, was isolated from marine water of Tanjung Pelepas, Johor, Malaysia. The 5,684,538 bp genome of strain J15 comprised 3 contigs (2 chromosomes and 1 plasmid) with G + C content of 46.39 % and contained 4924 protein-coding genes including 180 tRNAs and 40 rRNAs. The phenotypic microarray (PM) as analyzed using BIOLOG showed the utilization of; i) 93 of the 190 carbon sources tested, where 61 compounds were used efficiently; ii) 41 of the 95 nitrogen sources tested, where 22 compounds were used efficiently; and iii) 3 of the 94 phosphorous and sulphur sources tested. Furthermore, high tolerance to osmotic stress, basic pH and toxic compounds as well as resistance to antibiotics of strain J15 were determined by BIOLOG PM. The ANI and kSNP analyses revealed that strain J15 to be the same species with Photobacterium marinum AK15 with ANI value of 96.93 % and bootstrapping value of 100 in kSNP. Based on the ANI and kSNP analyses, strain J15 was identified as P. marinum J15.
Topics: Aquatic Organisms; Base Composition; DNA, Bacterial; Genome, Bacterial; Genomics; Malaysia; Phenomics; Photobacterium; Phylogeny; Seawater; Sequence Analysis, DNA
PubMed: 31945517
DOI: 10.1016/j.micres.2020.126410 -
Infection and Immunity Apr 2015Photobacterium damselae subsp. damselae is a marine bacterium that causes septicemia in marine animals and in humans. Previously, we had determined a major role of...
Photobacterium damselae subsp. damselae is a marine bacterium that causes septicemia in marine animals and in humans. Previously, we had determined a major role of pPHDD1 plasmid-encoded Dly (damselysin) and HlyA (HlyApl) and the chromosome-encoded HlyA (HlyAch) hemolysins in virulence. However, the mechanisms by which these toxins are secreted remain unknown. In this study, we found that a mini-Tn10 transposon mutant in a plasmidless strain showing an impaired hemolytic phenotype contained an insertion in epsL, a component of a type II secretion system (T2SS). Reconstruction of the mutant by allelic exchange confirmed the specific involvement of epsL in HlyAch secretion. In addition, mutation of epsL in a pPHDD1-harboring strain caused an almost complete abolition of hemolytic activity against sheep erythrocytes, indicating that epsL plays a major role in secretion of the plasmid-encoded HlyApl and Dly. This was further demonstrated by analysis of different combinations of hemolysin gene mutants and by strain-strain complementation assays. We also found that mutation of the putative prepilin peptidase gene pilD severely affected hemolysis, which dropped at levels inferior to those of epsL mutants. Promoter expression analyses suggested that impairment of hemolysin secretion in epsL and pilD mutants might constitute a signal that affects hemolysin and T2SS gene expression at the transcriptional level. In addition, single epsL and pilD mutations caused a drastic decrease in virulence for mice, demonstrating a major role of T2SS and pilD in P. damselae subsp. damselae virulence.
Topics: Animals; Bacterial Proteins; Bacterial Secretion Systems; Base Sequence; Endopeptidases; Erythrocytes; Hemolysin Proteins; Hemolysis; Mice; Mice, Inbred BALB C; Mutation; Photobacterium; Plasmids; Sequence Analysis, DNA; Transcription, Genetic; Transposases; Virulence Factors
PubMed: 25583529
DOI: 10.1128/IAI.02608-14