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International Journal of Molecular... Aug 2022The genus is known for its ecophysiological versatility encompassing free-living, symbiotic, and pathogenic lifestyles. sp. CCB-ST2H9 was isolated from estuarine...
The genus is known for its ecophysiological versatility encompassing free-living, symbiotic, and pathogenic lifestyles. sp. CCB-ST2H9 was isolated from estuarine sediment collected at Matang Mangrove, Malaysia. In this study, the genome of CCB-ST2H9 was sequenced, and the pan-genome of 37 strains was analysed. Phylogeny based on core genes showed that CCB-ST2H9 clustered with , forming a distinct clade with , , and . The core genome of was conserved in housekeeping functions, while the flexible genome was well represented by environmental genes related to energy production and carbohydrate metabolism. Genomic metrics including 16S rRNA sequence similarity, average nucleotide identity, and digital DNA-DNA hybridization values were below the cut-off for species delineation, implying that CCB-ST2H9 potentially represents a new species. Genome mining revealed that biosynthetic gene clusters (BGCs) involved in producing antimicrobial compounds such as holomycin in CCB-ST2H9 could contribute to the antagonistic potential. Furthermore, the EtOAc extract from the culture broth of CCB-ST2H9 exhibited antagonistic activity against spp. Intriguingly, clustering based on BGCs profiles grouped , , , , and CCB-ST2H9 together in the heatmap by the presence of a large number of BGCs. These BGCs-rich strains represent great potential for bioactive secondary metabolites production and sources for novel compounds.
Topics: Bacterial Typing Techniques; Base Composition; DNA, Bacterial; Fatty Acids; Genomics; Multigene Family; Photobacterium; Phylogeny; RNA, Ribosomal, 16S; Sequence Analysis, DNA
PubMed: 36077108
DOI: 10.3390/ijms23179712 -
Infection and Immunity Sep 2013Photobacterium damselae subsp. damselae causes infections and fatal disease in marine animals and in humans. Highly hemolytic strains produce damselysin (Dly) and...
Photobacterium damselae subsp. damselae causes infections and fatal disease in marine animals and in humans. Highly hemolytic strains produce damselysin (Dly) and plasmid-encoded HlyA (HlyA(pl)). These hemolysins are encoded by plasmid pPHDD1 and contribute to hemolysis and virulence for fish and mice. In this study, we report that all the hemolytic strains produce a hitherto uncharacterized chromosome-encoded HlyA (HlyAch). Hemolysis was completely abolished in a single hlyAch mutant of a plasmidless strain and in a dly hlyApl hlyAch triple mutant. We found that Dly, HlyA(pl), and HlyAch are needed for full hemolytic values in strains harboring pPHDD1, and these values are the result of the additive effects between HlyApl and HlyAch, on the one hand, and of the synergistic effect of Dly with HlyApl and HlyAch, on the other hand. Interestingly, Dly-producing strains produced synergistic effects with strains lacking Dly production but secreting HlyA, constituting a case of the CAMP (Christie, Atkins, and Munch-Petersen) reaction. Environmental factors such as iron starvation and salt concentration were found to regulate the expression of the three hemolysins. We found that the contributions, in terms of the individual and combined effects, of the three hemolysins to hemolysis and virulence varied depending on the animal species tested. While Dly and HlyApl were found to be main contributors in the virulence for mice, we observed that the contribution of hemolysins to virulence for fish was mainly based on the synergistic effects between Dly and either of the two HlyA hemolysins rather than on their individual effects.
Topics: Animals; Chromosomes; Escherichia coli; Fish Diseases; Fishes; Hemolysin Proteins; Hemolysis; Iron; Mice; Mice, Inbred BALB C; Photobacterium; Plasmids; Sodium Chloride; Transcription, Genetic; Virulence
PubMed: 23798530
DOI: 10.1128/IAI.00155-13 -
Heliyon Nov 2023is a unique traditional Icelandic product and is obtained by fermenting and drying Greenland shark (). However, little is known about the chemical and microbial changes...
is a unique traditional Icelandic product and is obtained by fermenting and drying Greenland shark (). However, little is known about the chemical and microbial changes occurring during the process. In this small-scale industrial study, fresh and frozen shark meat was fermented for eight and seven weeks, respectively, and then dried for five weeks. During the fermentation, trimethylamine -oxide levels decreased to below the limit of detection within five weeks and pH increased from about 6 to 9. Simultaneously, trimethylamine and dimethylamine levels increased significantly. Total viable plate counts, and specific spoilage organisms increased during the first weeks of the fermentation period but decreased during drying. Culture-independent analyses (16S rRNA) revealed gradual shifts in the bacterial community structure as fermentation progressed, dividing the fermentation process into three distinct phases but stayed rather similar throughout the drying process. During the first three weeks of fermentation, was dominant in the fresh group, compared to in the frozen group. However, as the fermentation progressed, the groups became more alike with , and being dominant. The PCA analysis done on the chemical variables and 16S rRNA analysis variables confirmed the correlation between high concentrations of TMAO and and at the initial fermentation phase. During the final fermentation phase, correlation was detected between high concentrations of TMA/DMA and , and . The results indicate the possibility to shortening the fermentation period and it is suggested that the microbial community can potentially be standardized with starter cultures to gain an optimal fermentation procedure.
PubMed: 38074871
DOI: 10.1016/j.heliyon.2023.e22127 -
International Journal of Molecular... Nov 2022Polyhydroxyalkanoates (PHA) are promising biodegradable and biocompatible bioplastics, and extensive knowledge of the employed bacterial strain's metabolic capabilities...
Polyhydroxyalkanoates (PHA) are promising biodegradable and biocompatible bioplastics, and extensive knowledge of the employed bacterial strain's metabolic capabilities is necessary in choosing economically feasible production conditions. This study aimed to create an in-depth view of the utilization of C2.2 for PHA production by linking a wide array of characterization methods: metabolic pathway annotation from the strain's complete genome, high-throughput phenotypic tests, and biomass analyses through plate-based assays and flask and bioreactor cultivations. We confirmed, in PHA production conditions, urea catabolization, fatty acid degradation and synthesis, and high pH variation and osmotic stress tolerance. With urea as a nitrogen source, pure and rapeseed-biodiesel crude glycerol were analyzed comparatively as carbon sources for fermentation at 20 °C. Flask cultivations yielded 2.2 g/L and 2 g/L PHA at 120 h, respectively, with molecular weights of 428,629 g/mol and 81,515 g/mol. Bioreactor batch cultivation doubled biomass accumulation (10 g/L and 13.2 g/L) in 48 h, with a PHA productivity of 0.133 g/(L·h) and 0.05 g/(L·h). Thus, phenotypic and genomic analyses determined the successful use of C2.2 for PHA production using urea and crude glycerol and 20 g/L NaCl, without pH adjustment, providing the basis for a viable fermentation process.
Topics: Brassica napus; Polyhydroxyalkanoates; Glycerol; Biofuels; Brassica rapa; Genomics; Urea
PubMed: 36430242
DOI: 10.3390/ijms232213754 -
International Journal of Molecular... Mar 2023subsp. () is a Gram-negative fish pathogen with worldwide distribution and broad host specificity that causes heavy economic losses in aquaculture. Although was first...
subsp. () is a Gram-negative fish pathogen with worldwide distribution and broad host specificity that causes heavy economic losses in aquaculture. Although was first identified more than 50 years ago, its pathogenicity mechanisms are not completely understood. In this work, we report that secretes large amounts of outer membrane vesicles (OMVs) when cultured in vitro and during in vivo infection. These OMVs were morphologically characterized and the most abundant vesicle-associated proteins were identified. We also demonstrate that OMVs protect cells from the bactericidal activity of fish antimicrobial peptides, suggesting that secretion of OMVs is part of the strategy used by to evade host defense mechanisms. Importantly, the vaccination of sea bass () with adjuvant-free crude OMVs induced the production of anti- antibodies and resulted in partial protection against infection. These findings reveal new aspects of biology and may provide a basis for developing new vaccines against this pathogen.
Topics: Animals; Bass; Photobacterium; Virulence; Vaccines; Fish Diseases; Gram-Negative Bacterial Infections
PubMed: 36982212
DOI: 10.3390/ijms24065138 -
Frontiers in Microbiology 2019The RstB histidine kinase of the two component system RstAB positively regulates the expression of damselysin (Dly), phobalysin P (PhlyP) and phobalysin C (PhlyC)...
The RstAB System Impacts Virulence, Motility, Cell Morphology, Penicillin Tolerance and Production of Type II Secretion System-Dependent Factors in the Fish and Human Pathogen subsp. .
The RstB histidine kinase of the two component system RstAB positively regulates the expression of damselysin (Dly), phobalysin P (PhlyP) and phobalysin C (PhlyC) cytotoxins in the fish and human pathogen subsp. , a marine bacterium of the family . However, the function of the predicted cognate response regulator RstA has not been studied so far, and the role of the RstAB system in other cell functions and phenotypes remain uninvestigated. Here, we analyzed the effect of and mutations in cell fitness and in diverse virulence-related features. Both and mutants were severely impaired in virulence for sea bream and sea bass fish. Mutants in and genes were impaired in hemolysis and in Dly-dependent phospholipase activity but had intact PlpV-dependent phospholipase and ColP-dependent gelatinase activities. and mutants grown at 0.5% NaCl exhibited impaired swimming motility, enlarged cell size and impaired ability to separate after cell division, whereas at 1% NaCl the mutants exhibited normal phenotypes. Mutation of any of the two genes also impacted tolerance to benzylpenicillin. Notably, and mutants showed impaired secretion of a number of type II secretion system (T2SS)-dependent proteins, which included the three major cytotoxins Dly, PhlyP and PhlyC, as well as a putative delta-endotoxin and three additional uncharacterized proteins which might constitute novel virulence factors of this pathogenic bacterium. The analysis of the T2SS-dependent secretome of subsp. also led to the identification of RstAB-independent potential virulence factors as lipoproteins, sialidases and proteases. The RstAB regulon included plasmid, chromosome I and chromosome II-encoded genes that showed a differential distribution among isolates of this subspecies. This study establishes RstAB as a major regulator of virulence and diverse cellular functions in subsp. .
PubMed: 31105680
DOI: 10.3389/fmicb.2019.00897 -
International Microbiology : the... Mar 2002Pasteurellosis, or pseudotuberculosis, is a bacterial septicaemia caused by the halophilic bacterium Photobacterium damselae subsp. piscicida (formerly Pasteurella... (Review)
Review
Pasteurellosis, or pseudotuberculosis, is a bacterial septicaemia caused by the halophilic bacterium Photobacterium damselae subsp. piscicida (formerly Pasteurella piscicida). Although this disease was first described in wild populations of white perch and striped bass, currently the natural hosts of the pathogen are a wide variety of marine fish. The disease has great economic impact both in Japan, where it affects mainly yellowtail cultures, and in the Mediterranean area, due to the losses it causes in seabream and seabass farms. This microorganism serves as a perfect model to study a bacterial fish pathogen, either at an applied level, to resolve or to mitigate the high economic losses of fish farmers, or at a basic level, for a better understanding of P. damselae subsp. piscicida biology. This article discusses the methods employed in our laboratory to study the causative agent of pasteurellosis. It reviews important aspects, from the diverse procedures for the detection and isolation of the pathogen to the latest molecular studies that have allowed its correct taxonomic allocation. Characterization of some virulence mechanisms and the available methods to prevent the disease are also presented.
Topics: Animals; Bacteremia; Fish Diseases; Gram-Negative Bacterial Infections; Molecular Diagnostic Techniques; Pasteurella Infections; Phenotype; Photobacterium; Virulence
PubMed: 12102234
DOI: 10.1007/s10123-002-0051-6 -
Frontiers in Microbiology 2021Chondroitin sulfate (CS)/dermatan sulfate (DS) is a kind of sulfated polyanionic, linear polysaccharide belonging to glycosaminoglycan. CS/DS sulfatases, which...
Chondroitin sulfate (CS)/dermatan sulfate (DS) is a kind of sulfated polyanionic, linear polysaccharide belonging to glycosaminoglycan. CS/DS sulfatases, which specifically hydrolyze sulfate groups from CS/DS oligo-/polysaccharides, are potential tools for structural and functional studies of CD/DS. However, only a few sulfatases have been reported and characterized in detail to date. In this study, two CS/DS sulfatases, PB_3262 and PB_3285, were identified from the marine bacterium sp. QA16 and their action patterns were studied in detail. PB_3262 was characterized as a novel 4--endosulfatase that can effectively and specifically hydrolyze the 4--sulfate group of disaccharide GlcUAβ1-3GalNAc(4--sulfate) but not GlcUAβ1-3GalNAc(4,6--sulfate) and IdoUAα1-3GalNAc(4--sulfate) in CS/DS oligo-/polysaccharides, which is very different from the identified 4--endosulfatases in the substrate profile. In contrast, PB_3285 specifically hydrolyzes the 6--sulfate groups of GalNAc(6--sulfate) residues located at the reducing ends of the CS chains and is the first recombinantly expressed 6--exosulfatase to effectively act on CS oligosaccharides.
PubMed: 35140691
DOI: 10.3389/fmicb.2021.775124 -
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 -
Shokuhin Eiseigaku Zasshi. Journal of... 2022Histamine poisoning has been reported worldwide. Improvements in refrigeration technology have led to a reduction in this food poisoning; however, it continues to occur.... (Review)
Review
Histamine poisoning has been reported worldwide. Improvements in refrigeration technology have led to a reduction in this food poisoning; however, it continues to occur. Misdiagnosis of fish allergies has compounded this problem and the number of patients subjected to histamine poisoning that are transported to the emergency ward because of anaphylactic shock-like symptoms should not be underestimated. We investigated incidents of histamine food poisoning in Japan from 1998 to 2020, and found that there were a mean 9.7 incidents/year and 195.3 cases/year. Facility-wise occurrence of the incidents per year was the highest in restaurants followed by lunch facilities, and these together accounted for approximately 70% of the incidents. Facility-wise total number of cases was the highest in lunch facilities followed by restaurants, and these together accounted for 80% of the cases. Fish associated with histamine poisoning were mainly tuna, marlin, and mackerel. Based on the current literature review, 23 genera of histamine-producing bacteria were isolated from fish purchased in Japan. The most frequently reported bacteria were Morganella morganii and Photobacterium damselae. Psychrophilic bacteria such as Morganella psychrotolerans and Photobacterium phosphoreum were also isolated. To prevent histamine poisoning, freezing or fast handling of fish and the products during processing and consuming is important because only refrigeration of fish is enough.
Topics: Animals; Bacteria; Fishes; Food Microbiology; Foodborne Diseases; Histamine; Japan
PubMed: 35858795
DOI: 10.3358/shokueishi.63.109