-
Frontiers in Microbiology Sep 2013Photobacterium damselae subsp. damselae (formerly Vibrio damsela) is a pathogen of a variety of marine animals including fish, crustaceans, molluscs, and cetaceans. In... (Review)
Review
Photobacterium damselae subsp. damselae (formerly Vibrio damsela) is a pathogen of a variety of marine animals including fish, crustaceans, molluscs, and cetaceans. In humans, it can cause opportunistic infections that may evolve into necrotizing fasciitis with fatal outcome. Although the genetic basis of virulence in this bacterium is not completely elucidated, recent findings demonstrate that the phospholipase-D Dly (damselysin) and the pore-forming toxins HlyApl and HlyAch play a main role in virulence for homeotherms and poikilotherms. The acquisition of the virulence plasmid pPHDD1 that encodes Dly and HlyApl has likely constituted a main driving force in the evolution of a highly hemolytic lineage within the subspecies. Interestingly, strains that naturally lack pPHDD1 show a strong pathogenic potential for a variety of fish species, indicating the existence of yet uncharacterized virulence factors. Future and deep analysis of the complete genome sequence of Photobacterium damselae subsp. damselae will surely provide a clearer picture of the virulence factors employed by this bacterium to cause disease in such a varied range of hosts.
PubMed: 24093021
DOI: 10.3389/fmicb.2013.00283 -
Animal Microbiome May 2022Invertebrates are a very attractive subject for studying host-microbe interactions because of their simple gut microbial community and host diversity. Studying the...
BACKGROUND
Invertebrates are a very attractive subject for studying host-microbe interactions because of their simple gut microbial community and host diversity. Studying the composition of invertebrate gut microbiota and the determining factors is essential for understanding their symbiotic mechanism. Cephalopods are invertebrates that have similar biological properties to vertebrates such as closed circulation system, an advanced nervous system, and a well-differentiated digestive system. However, it is not currently known whether their microbiomes have more in common with vertebrates or invertebrates. This study reports on the microbial composition of six cephalopod species and compares them with other mollusk and marine fish microbiomes to investigate the factors that shape the gut microbiota.
RESULTS
Each cephalopod gut consisted of a distinct consortium of microbes, with Photobacterium and Mycoplasma identified as core taxa. The gut microbial composition of cephalopod reflected their host phylogeny, the importance of which was supported by a detailed oligotype-level analysis of operational taxonomic units assigned to Photobacterium and Mycoplasma. Photobacterium typically inhabited multiple hosts, whereas Mycoplasma tended to show host-specific colonization. Furthermore, we showed that class Cephalopoda has a distinct gut microbial community from those of other mollusk groups or marine fish. We also showed that the gut microbiota of phylum Mollusca was determined by host phylogeny, habitat, and diet.
CONCLUSION
We have provided the first comparative analysis of cephalopod and mollusk gut microbial communities. The gut microbial community of cephalopods is composed of distinctive microbes and is strongly associated with their phylogeny. The Photobacterium and Mycoplasma genera are core taxa within the cephalopod gut microbiota. Collectively, our findings provide evidence that cephalopod and mollusk gut microbiomes reflect host phylogeny, habitat, and diet. It is hoped that these data can contribute to future studies on invertebrate-microbe interactions.
PubMed: 35527289
DOI: 10.1186/s42523-022-00184-x -
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 -
Frontiers in Immunology 2021Cobia () is a marine fish of high economic value that grows at a fast rate. However, intensive fish farming has led to disease outbreaks in cobia cultures, which is...
Cobia () is a marine fish of high economic value that grows at a fast rate. However, intensive fish farming has led to disease outbreaks in cobia cultures, which is highly costly to the industry. The impact of infectious diseases on cobia production has led to the inappropriate and increased use of chemicals and antibiotics, which negatively affects the environment and human health and promotes the spread of drug-resistant pathogens. Hence, prophylactic measurements, such as the use of immunomodulators, are required to improve the health of cultured animals against pathogens. In this study, we examined the effects of water extract (SSWE) in cobia and . We found that treatment with SSWE could significantly increase the expression of cytokines (e.g., , , , , and ) and chemokines (e.g., ) in primary cultured head kidney leukocytes. Intraperitoneal injection of SSWE (20 μg/g body weight) promoted higher expression of , , , , chemokines (e.g., ), and antibodies (e.g., ) in head kidney and spleen tissues of the fish compared with other dose levels. Additionally, we describe for the second time (only after India) of the isolation of subsp. () from a deadly epizootic in cage-farmed cobia. An intraperitoneal inoculation of SSWE before challenge showed that SSWE treatment could delay the onset of mortality of cobia. Finally, fish that received SSWE intraperitoneally before infection with exhibited elevated expression of Th1-type cytokines, namely, , , , and . At the same time, the expression of Th2-related factors (such as in the head kidney, and and in the spleen) were lower for the fish that received SSWE instead of PBS before the challenge. The results indicate that SSWE treatment facilitates the induction of Th1-type cytokines in cobia to fight against infection and has the potential to be used as an immunostimulant and vaccine adjuvant for fish.
Topics: Animals; Biological Products; Cytokines; Fish Diseases; Host-Pathogen Interactions; Immunity, Innate; Inflammation Mediators; Mortality; Photobacterium; Rhodophyta; Th1 Cells; Transcriptome
PubMed: 35140710
DOI: 10.3389/fimmu.2021.801501 -
Toxins Apr 2010Photobacterium damselae subsp. piscicida (Phdp) is a Gram-negative pathogen agent of an important fish septicemia. The key virulence factor of Phdp is the... (Review)
Review
Photobacterium damselae subsp. piscicida (Phdp) is a Gram-negative pathogen agent of an important fish septicemia. The key virulence factor of Phdp is the plasmid-encoded exotoxin AIP56, which is secreted by exponentially growing pathogenic strains. AIP56 has 520 amino acids including an N-terminal cleavable signal peptide of 23 amino acid residues, two cysteine residues and a zinc-binding region signature HEXXH that is typical of most zinc metallopeptidases. AIP56 induces in vitro and in vivo selective apoptosis of fish macrophages and neutrophils through a caspase-3 dependent mechanism that also involves caspase-8 and -9. In vivo, the AIP56-induced phagocyte apoptosis progresses to secondary necrosis with release of cytotoxic phagocyte molecules including neutrophil elastase. Fish injected with recombinant AIP56 die with a pathology similar to that seen in the natural infection.
Topics: Animals; Apoptosis; Bacterial Toxins; Humans; Macrophages; Neutrophils; Photobacterium; Virulence Factors
PubMed: 22069616
DOI: 10.3390/toxins2040905 -
Applied and Environmental Microbiology May 2019spp. are ubiquitous marine bacteria with high metabolism flexibility and genome plasticity. Previous studies have revealed the dynamics of planktonic vibrios in...
spp. are ubiquitous marine bacteria with high metabolism flexibility and genome plasticity. Previous studies have revealed the dynamics of planktonic vibrios in relation to environmental forces, such as temperature and salinity. However, little is known about ecology in benthic environments. Here, we elucidate the abundance, diversity, and spatial distribution of spp. in sediments of the Chinese marginal seas, with a wide spatial range from north to south covering the Yellow Sea (YS), East China Sea (ECS), and South China Sea (SCS). Quantitative analysis showed that spp. were most abundant in the SCS (∼9.04 × 10 copies/g) compared to the YS (∼1.00 × 10 copies/g) and ECS (∼8.86 × 10 copies/g). community compositions derived from Illumina sequencing of -specific 16S rRNA genes varied significantly between sampling areas, which was reflected by a strong distance-decay pattern. The spatial distribution of was governed by a joint effect of spatial and environmental factors (especially temperature, salinity, and SiO), and their respective pure effects explained only a small fraction of the community variation. Moreover, we identified the most prominent operational taxonomic units (OTUs) that were partitioned in these sea areas. Whereas OTU20 and were prevalent in the YS, and , and , , and were prevalent in the ECS and SCS, respectively. Our study demonstrated clear spatial heterogeneity of spp. in sediments of the Chinese marginal seas, laying a foundation for fully understanding the marine ecology and the ecological roles of the species. is an important component of natural marine microbial populations in terms of pathogenicity and roles in carbon cycling. Compared to the marine pelagic environment, our knowledge of the diversity and distribution pattern of spp. in sediment is limited. Here, we show higher abundance in Chinese marginal seas than in other studied sediments. There was a clear spatial differentiation of abundance and community composition in different sea areas. The benthic community displayed a strong distance-decay pattern across a wide spatial range, which was formed under the combined effects of spatial and environmental factors. These results provide deep insights into the ecological dynamics of and its environmental controls, facilitating a more comprehensive understanding of the marine ecology.
Topics: Biodiversity; China; Geologic Sediments; Oceans and Seas; Vibrio
PubMed: 30877118
DOI: 10.1128/AEM.03064-18 -
Journal of Food Protection Apr 2020The effects of high hydrostatic pressure (HHP) treatments on histamine-forming bacteria (HFB) Morganella morganii and Photobacterium phosphoreum in phosphate buffer and...
ABSTRACT
The effects of high hydrostatic pressure (HHP) treatments on histamine-forming bacteria (HFB) Morganella morganii and Photobacterium phosphoreum in phosphate buffer and tuna meat slurry were investigated using viability counting and scanning electron microscopy. The first-order model fits the destruction kinetics of high pressure on M. morganii and P. phosphoreum during the pressure hold period. The D-values of M. morganii (200 to 600 MPa) and P. phosphoreum (100 to 400 MPa) in phosphate buffer ranged from 16.4 to 0.08 min and 26.4 to 0.19 min, respectively, whereas those in tuna meat slurry ranged from 51.0 to 0.09 min and 71.6 to 0.19 min, respectively. M. morganii had higher D-values than P. phosphoreum at the same pressure, indicating it was more resistant to HHP treatment. HFB had a higher D-value in tuna meat slurry compared with that in phosphate buffer, indicating that the HFB were more resistant to pressure in tuna meat slurry. The Zp values (pressure range that results in a 10-fold change in D-value) of M. morganii and P. phosphoreum were 162 and 140 MPa in phosphate buffer and 153 and 105 MPa in tuna meat slurry, respectively. Damage to the cell wall and cell membrane by HHP treatments can be observed by scanning electron microscopy. To our knowledge, this is the first report to demonstrate that HHP can be applied to inactivate the HFB M. morganii and P. phosphoreum by inducing morphological changes in the cells.
Topics: Animals; Food Handling; Food Preservation; Histamine; Morganella morganii; Photobacterium; Pressure
PubMed: 32221566
DOI: 10.4315/0362-028X.JFP-19-267 -
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 -
Frontiers in Microbiology 2022Modified atmosphere packaging (MAP) is a common strategy to selectively prevent the growth of certain species of meat spoiling bacteria. This study aimed to determine...
Modified atmosphere packaging (MAP) is a common strategy to selectively prevent the growth of certain species of meat spoiling bacteria. This study aimed to determine the impact of high oxygen MAP (70% O, 30% CO, red and white meats) and oxygen-free MAP (70% N, 30% CO, also white meat and seafood) on preventing the growth of spoiling photobacteria on meat. Growth of and was monitored in a meat simulation media under different gas mixtures of nitrogen, oxygen, and carbon dioxide, and samples were taken during exponential growth for a comparative proteomic analysis. Growth under air atmosphere appears optimal, particularly for . Enhanced protein accumulation affected energy metabolism, respiration, oxygen consuming reactions, and lipid usage. However, all the other atmospheres show some degree of growth reduction. An increase in oxygen concentration leads to an increase in enzymes counteracting oxidative stress for both species and enhancement of heme utilization and iron-sulfur cluster assembly proteins for . Absence of oxygen appears to switch the metabolism toward fermentative pathways where either ribose ( or glycogen ( appear to be the preferred substrates. Additionally, it promotes the use of alternative electron donors/acceptors, mainly formate and nitrate/nitrite. Stress response is manifested as an enhanced accumulation of enzymes that is able to produce ammonia (e.g., carbonic anhydrase, hydroxylamine reductase) and regulate osmotic stress. Our results suggest that photobacteria do not sense the environmental levels of carbon dioxide, but rather adapt to their own anaerobic metabolism. The regulation in presence of carbon dioxide is limited and strain-specific under anaerobic conditions. However, when oxygen at air-like concentration (21%) is present together with carbon dioxide (30%), the oxidative stress appears enhanced compared to air conditions (very low carbon dioxide), as explained if both gases have a synergistic effect. This is further supported by the increase in oxygen concentration in the presence of carbon dioxide. The atmosphere is able to fully inhibit , heavily reduce growth , and trigger diversification of energy production with higher energetic cost, highlighting the importance of concomitant bacteria for their growth on raw meat under said atmosphere.
PubMed: 35722325
DOI: 10.3389/fmicb.2022.866629 -
Microbial Genomics Apr 2021Despite the recent advances in sequencing technologies, the complete assembly of multi-chromosome genomes of the , often containing several plasmids, remains...
Despite the recent advances in sequencing technologies, the complete assembly of multi-chromosome genomes of the , often containing several plasmids, remains challenging. Using a combination of Oxford Nanopore MinION long reads and short Illumina reads, we fully sequenced, closed and curated the genomes of two strains of a primary aquatic pathogen subsp. isolated in Australia. These are also the first genome sequences of subsp. isolated in Oceania and, to our knowledge, in the Southern hemisphere. We also investigated the phylogenetic relationships between Australian and overseas isolates, revealing that Australian subsp. are more closely related to the Asian and American strains rather than to the European ones. We investigated the mobilome and present new evidence showing that a host specialization process and progressive adaptive evolution to fish are ongoing in subsp. , and are largely mediated by transposable elements, predominantly in chromosome 2, and by plasmids. Finally, we identified two novel potential virulence determinants in subsp. - a chorismate mutase gene, which is ubiquitously retained and co-localized with the AIP56 apoptogenic toxin-encoding gene on the pPHDP10 plasmid, and transfer-messenger RNA gene located on the main chromosome, homologous to a critical-to-virulence determinant in . Our study describes, to our knowledge, the only fully closed and manually curated genomes of subsp. available to date, offering new insights into this important fish pathogen and its evolution.
Topics: Bacterial Proteins; Chromosome Mapping; DNA Transposable Elements; Evolution, Molecular; Genome, Bacterial; Photobacterium; Phylogeny; Virulence Factors
PubMed: 33885359
DOI: 10.1099/mgen.0.000562