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International Journal of Food... Jul 2023The aim of this study was to investigate seasonal variations (September, December and April) in the initial microbial communities of skin and gills' external mucosal...
Photobacterium predominate the microbial communities of muscle of European plaice (Pleuronectes platessa) caught in the Norwegian sea independent of skin and gills microbiota, fishing season, and storage conditions.
The aim of this study was to investigate seasonal variations (September, December and April) in the initial microbial communities of skin and gills' external mucosal tissues (EMT) and muscle of European plaice (Pleuronectes platessa). Moreover, a potential relationship between EMT and fresh muscle microbiota was examined. The microbial community succession in plaice muscle as a function of fishing season and storage conditions was also investigated. The selected seasons for the storage experiment were September and April. Investigated storage conditions were; fillets packaged in either vacuum or modified atmosphere (70 % CO, 20 % N, 10 % O) and chilled/refrigerated conditions (4 °C). Whole fish stored on ice (0 °C) was selected as a commercial standard. Seasonal variations were detected in the initial microbial communities of EMT and plaice muscle. The highest microbial diversity was found in EMT and muscle of April-caught plaice, followed by December and September catch indicating the important role of environmental factors in shaping the initial EMT and muscle microbial communities. The EMT microbial communities were more diverse than fresh muscle samples. The low number of shared taxa between EMT and initial muscle microbial communities indicates that only a minor part of the muscle microbiota came from the EMT. Psychrobacter and Photobacterium were the predominant genera in the EMT microbial communities in all seasons. Photobacterium dominated the initial muscle microbial communities with a gradual seasonal reduction of its abundance from September to April. Storage time and storage conditions shaped a less diverse and distinct community compared to the fresh muscle. However, no clear separation was seen between the communities at the middle and end of storage time. Regardless of EMT microbiota, fishing season and storage conditions, Photobacterium dominated the microbial communities of stored muscle samples. The Photobacterium prevalence as the primary specific spoilage organism (SSO) could be attributed to its high relative abundance in the initial microbiota of muscle and its CO-tolerance. The findings of this study indicate the important contribution of Photobacterium to the microbial spoilage of plaice. Thus, the development of innovative preservation techniques addressing the rapid growth of Photobacterium could contribute to the production of high-quality and shelf-stable convenient retail plaice products.
Topics: Animals; Carbon Dioxide; Flounder; Food Microbiology; Food Packaging; Food Preservation; Gills; Microbiota; Muscles; Photobacterium; Seasons
PubMed: 37099863
DOI: 10.1016/j.ijfoodmicro.2023.110222 -
Toxins Jul 2019Phobalysin P (PhlyP, for photobacterial lysin encoded on a plasmid) is a recently described small β-pore forming toxin of subsp. This organism, belonging to the... (Review)
Review
Phobalysin P (PhlyP, for photobacterial lysin encoded on a plasmid) is a recently described small β-pore forming toxin of subsp. This organism, belonging to the family of is an emerging pathogen of fish and various marine animals, which occasionally causes life-threatening soft tissue infections and septicemia in humans. By using genetically modified strains, PhlyP was found to be an important virulence factor. More recently, in vitro studies with purified PhlyP elucidated some basic consequences of pore formation. Being the first bacterial small β-pore forming toxin shown to trigger calcium-influx dependent membrane repair, PhlyP has advanced to a revealing model toxin to study this important cellular function. Further, results from co-culture experiments employing various strains and epithelial cells together with data on other bacterial toxins indicate that limited membrane damage may generally enhance the association of bacteria with target cells. Thereby, remodeling of plasma membrane and cytoskeleton during membrane repair could be involved. In addition, a chemotaxis-dependent mechanism influenced by environmental factors like salinity may contribute to PhlyP-dependent association of with cells. Obviously, a synoptic approach is required to capture the regulatory links governing the interaction of with target cells. The characterization of secretome may hold additional clues because it may lead to the identification of proteases activating PhlyP's pro-form. Current findings on PhlyP support the notion that pore forming toxins are not just killer proteins but serve bacteria to fulfill more subtle functions, like accessing their host.
Topics: Animals; Bacterial Proteins; Cell Adhesion; Cell Membrane; Chemotaxis; Epithelial Cells; Hemolysin Proteins; Humans; Phenotype; Photobacterium
PubMed: 31315179
DOI: 10.3390/toxins11070412 -
Journal of Fish Diseases Dec 2020Mass mortality has occurred among cultured Nile tilapia, Oreochromis niloticus, on fish farms in Manzala, Dakahlia province, Egypt, in the summer season, 2019. Moribund...
Mass mortality has occurred among cultured Nile tilapia, Oreochromis niloticus, on fish farms in Manzala, Dakahlia province, Egypt, in the summer season, 2019. Moribund fish were reported with deep ulcers, septicaemic lesions and sampled for bacterial isolation. In this study, most isolates were subjected to bacteriological examination, antibiotic sensitivity test, 16S rRNA gene sequencing and histopathological examination. Following isolate identification, intraperitoneal challenge of Nile tilapia with a bacterial suspension 2 × 10 CFU/ml was performed. Samples from liver, spleen and kidney were collected for histological and biochemical analysis. The results showed a high similarity (99%) to Photobacterium damselae strains using phylogenetic analysis of 16S rRNA. P. damselae exhibited resistance to amoxicillin and erythromycin, as well it was highly sensitive to chloramphenicol and doxycycline. Moreover, haemorrhage, oedema, hemosiderosis and melanomacrophage activation in the liver and head kidney of infected fish were detected by light and electron microscopy. Also, significant higher levels of CAT and SOD in the spleen and head kidney, as well as the serum levels of NO were observed in experimentally challenged O. niloticus, compared to the control fish. Our data identified P. damselae for the first time from infected Nile tilapia, describing its sensitivity to a variety of antibiotics, histopathological alterations and oxidative stress impact, and it could be useful indicators for understanding P. damselae pathogenesis, which might provide a preventive efficacy for P. damselae.
Topics: Animals; Aquaculture; Cichlids; Drug Resistance, Bacterial; Egypt; Fish Diseases; Gram-Negative Bacterial Infections; Microbial Sensitivity Tests; Photobacterium; RNA, Ribosomal, 16S
PubMed: 32984991
DOI: 10.1111/jfd.13251 -
Animal Microbiome Mar 2022Sharks play essential roles in ocean food webs and human culture, but also face population declines worldwide due to human activity. The relationship between sharks and...
BACKGROUND
Sharks play essential roles in ocean food webs and human culture, but also face population declines worldwide due to human activity. The relationship between sharks and the microbes on and in the shark body is unclear, despite research on other animals showing the microbiome as intertwined with host physiology, immunity, and ecology. Research on shark-microbe interactions faces the significant challenge of sampling the largest and most elusive shark species. We leveraged a unique sampling infrastructure to compare the microbiomes of two apex predators, the white (Carcharodon carcharias) and tiger shark (Galeocerdo cuvier), to those of the filter-feeding whale shark (Rhincodon typus), allowing us to explore the effects of feeding mode on intestinal microbiome diversity and metabolic function, and environmental exposure on the diversity of microbes external to the body (on the skin, gill).
RESULTS
The fecal microbiomes of white and whale sharks were highly similar in taxonomic and gene category composition despite differences in host feeding mode and diet. Fecal microbiomes from these species were also taxon-poor compared to those of many other vertebrates and were more similar to those of predatory teleost fishes and toothed whales than to those of filter-feeding baleen whales. In contrast, microbiomes of external body niches were taxon-rich and significantly influenced by diversity in the water column microbiome.
CONCLUSIONS
These results suggest complex roles for host identity, diet, and environmental exposure in structuring the shark microbiome and identify a small, but conserved, number of intestinal microbial taxa as potential contributors to shark physiology.
PubMed: 35246276
DOI: 10.1186/s42523-022-00168-x -
Journal of Applied Microbiology Jul 2020Several virulence factors of three new Photobacterium species: Photobacterium toruni, Photobacterium malacitanum and Photobacterium andalusiense associated with diseases...
AIMS
Several virulence factors of three new Photobacterium species: Photobacterium toruni, Photobacterium malacitanum and Photobacterium andalusiense associated with diseases of cultured redbanded seabream (Pagrus auriga) were studied. The exoenzymatic activities, adherence and cytotoxic capabilities, and iron-uptake mechanisms were determined both in bacterial extracellular products (ECP) and whole bacterial cells. The histopathology damages provoked on redbanded seabream by the ECP was also studied.
METHODS AND RESULTS
The highest exoenzymatic activities of the ECP were alkaline- and acid-phosphatase, phosphohydrolase and lipase. The ECP were strongly lethal for fish at 4-96 h post-inoculation (p.i). Histological changes were evident at 96 hpi of ECP, affecting head kidney, splenic parenchyma and heart. Cytotoxicity assays, on three fish lines and one human cell line, were conducted using whole bacterial cells and their ECP. The new species tested were cytotoxic only for fish cell lines using whole bacterial cells. Bacterial adherence showed an adherence index moderate on CHSE-214 cell line. All strains showed variable haemolytic activity, and were able to grow under iron-limiting conditions, although the CAS reactivitiy was very low. However, all strains produced high amounts of extracelullar citrate that could be used as iron carrier, and use haem as iron source, except the P. toruni strains because a deletion in the genomic region encoding this ability in all Vibrionaceae members.
CONCLUSIONS
The toxic activity of the bacterial ECPs was thermolabile, and not associated with their thermoresistant lipopolysaccharide content. The virulence of the strains tested could not be related to the haemolytic activity. Iron uptake could be based on the use of endogenous citrate as iron carrier and P. toruni lacks the ability to use haem as iron source.
SIGNIFICANCE AND IMPACT OF THE STUDY
The study analyses for the first time the virulence properties of three new species of Photobacterium pathogenic for fish.
Topics: Animals; Aquaculture; Cell Line; Fish Diseases; Gram-Negative Bacterial Infections; Humans; Photobacterium; Sea Bream; Virulence; Virulence Factors
PubMed: 31505106
DOI: 10.1111/jam.14437 -
Glycobiology Sep 2019The development of therapeutic proteins for the treatment of numerous diseases is one of the fastest growing areas of biotechnology. Therapeutic efficacy and serum...
The development of therapeutic proteins for the treatment of numerous diseases is one of the fastest growing areas of biotechnology. Therapeutic efficacy and serum half-life are particularly important, and these properties rely heavily on the glycosylation state of the protein. Expression systems to produce authentically fully glycosylated therapeutic proteins with appropriate terminal sialic acids are not yet perfected. The in vitro modification of therapeutic proteins by recombinant sialyltransferases offers a promising and elegant strategy to overcome this problem. Thus, the detailed expression and characterization of sialyltransferases for completion of the glycan chains is of great interest to the community. We identified a novel α2,6-sialyltransferase from Helicobacter cetorum and compared it to the human ST6Gal1 and a Photobacterium sp. sialyltransferase using glycoprotein substrates in a 96-well microtiter-plate-based assay. We demonstrated that the recombinant α2,6-sialyltransferase from H. cetorum is an excellent catalyst for modification of N-linked glycans of different therapeutic proteins.
Topics: Antigens, CD; Cloning, Molecular; Glycoproteins; Glycosylation; Helicobacter; Humans; Photobacterium; Polysaccharides; Protein Processing, Post-Translational; Sialic Acids; Sialyltransferases; beta-D-Galactoside alpha 2-6-Sialyltransferase
PubMed: 31281932
DOI: 10.1093/glycob/cwz050 -
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 -
Current Genetics Feb 2016Many proteobacteria modulate a suite of catabolic genes using the second messenger cyclic 3', 5'-AMP (cAMP) and the cAMP receptor protein (CRP). Together, the cAMP-CRP... (Review)
Review
Many proteobacteria modulate a suite of catabolic genes using the second messenger cyclic 3', 5'-AMP (cAMP) and the cAMP receptor protein (CRP). Together, the cAMP-CRP complex regulates target promoters, usually by activating transcription. In the canonical model, the phosphotransferase system (PTS), and in particular the EIIA(Glc) component for glucose uptake, provides a mechanistic link that modulates cAMP levels depending on glucose availability, resulting in more cAMP and activation of alternative catabolic pathways when glucose is unavailable. Within the Vibrionaceae, cAMP-CRP appears to play the classical role in modulating metabolic pathways; however, it also controls functions involved in natural competence, bioluminescence, pheromone signaling, and colonization of animal hosts. For this group of marine bacteria, chitin is an ecologically relevant resource, and chitin's monomeric sugar N-acetylglucosamine (NAG) supports robust growth while also triggering regulatory responses. Recent studies with Vibrio fischeri indicate that NAG and glucose uptake share EIIA(Glc), yet the responses of cAMP-CRP to these two carbon sources are starkly different. Moreover, control of cAMP levels appears to be more dominantly controlled by export and degradation. Perhaps more surprisingly, although CRP may require cAMP, its activity can be controlled in response to glucose by a mechanism independent of cAMP levels. Future studies in this area promise to shed new light on the role of cAMP and CRP.
Topics: Carbohydrate Metabolism; Cyclic AMP; Cyclic AMP Receptor Protein; Glucose; Vibrionaceae
PubMed: 26215147
DOI: 10.1007/s00294-015-0508-8 -
FEMS Microbiology Ecology Dec 2022The occurrence of pathogenic bacteria has emerged as a plausible key component of summer mortalities in mussels. In the current research, four bacterial isolates...
The occurrence of pathogenic bacteria has emerged as a plausible key component of summer mortalities in mussels. In the current research, four bacterial isolates retrieved from moribund Greenshell࣪ mussels, Perna canaliculus, from a previous summer mortality event, were tentatively identified as Vibrio and Photobacterium species using morpho-biochemical characterization and MALDI-TOF MS and confirmed as V. celticus, P. swingsii, P. rosenbergii, and P. proteolyticum using whole genome sequencing. These isolates were utilized in a laboratory challenge where mussels were injected with cell concentrations ranging from 105 to 109 CFU/mussel. Of the investigated isolates, P. swingsii induced the highest mortality. Additionally, results from quantitative polymerase chain reaction analysis, focusing on known virulence genes were detected in all isolates grown under laboratory conditions. Photobacterium rosenbergii and P. swingsii showed the highest expression levels of these virulence determinants. These results indicate that Photobacterium spp. could be a significant pathogen of P. canaliculus, with possible importance during summer mortality events. By implementing screening methods to detect and monitor Photobacterium concentrations in farmed mussel populations, a better understanding of the host-pathogen relationship can be obtained, aiding the development of a resilient industry in a changing environment.
Topics: Animals; Perna; Vibrio; Seasons; Virulence Factors; Seafood
PubMed: 36449667
DOI: 10.1093/femsec/fiac140 -
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