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Microorganisms Mar 2018Phylogenetic relationships between species in the genus have been poorly studied despite pathogenic and ecological relevance of some of its members. This is the first...
Phylogenetic relationships between species in the genus have been poorly studied despite pathogenic and ecological relevance of some of its members. This is the first phylogenetic study that includes new species of (validated or not) that have not been included in any of the previously described clades, using 16S rRNA sequences and multilocus sequence analysis (MLSA) in concatenated sequences of , , , and housekeeping genes. Sequence analysis has been implemented using Maximum-parsimony (MP), Neighbour-joining (NJ) and Maximum likelihood (ML) treeing methods and the predicted evolutionary relationship between the clades was established on the basis of bootstrap values of >75% for 16S rRNA sequences and MLSA. We have grouped 22 species of the genus into the following 5 clades: Phosphoreum (comprises , "," , , , "" and ""); clade Profundum (composed of , , , , , , "," and ); clade Damselae (two subspecies of , and ); and two new clades: clade Ganghwense (includes , , , , , and ); and clade Leiognathi (composed by , subsp. and " subsp. "). Two additional clades, Rosenbergii and Swingsii, were formed using a phylogenetic method based on 16S rRNA gene, although they are not confirmed by any MLSA methods. Only could not be included in none of the established clade, constituting an orphan clade.
PubMed: 29534541
DOI: 10.3390/microorganisms6010024 -
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 -
Current Research in Microbial Sciences Dec 2021() is a genus widely studied in regards to its association with and ubiquitous presence in marine environments. However, certain species () have been recently described...
() is a genus widely studied in regards to its association with and ubiquitous presence in marine environments. However, certain species () have been recently described to colonize and spoil raw meats without a marine link. We have studied 27 strains from meat as well as 26 strains from marine environments in order to probe for intraspecies marine/terrestrial subpopulations and identify distinct genomic features acquired by environmental adaptation. We have conducted phylogenetic analysis (MLSA, ANI, , codon usage), search of plasmids (plasmidSPADES), phages (PHASTER), CRISPR-cas operons (CRISPR-finder) and secondary metabolites gene clusters (antiSMASH, BAGEL), in addition to a targeted gene search for specific pathways (e.g. TCA cycle, pentose phosphate, respiratory chain) and elements relevant for growth, adaptation and competition (substrate utilization, motility, bioluminescence, sodium and iron transport). appears as a conserved single clade, with one isolate from MAP fish clustering apart that doesn't, however, show distinct features that could indicate different adaptation. The species harbors genes for a wide carbon source utilization (glycogen/starch, maltose, pullulan, fucose) for colonization of diverse niches in its genome. is represented by two different clades on the phylogenetic analyses not correlating to their origin or distribution of other features analyzed that can be divided into two novel subspecies based on genome-wide values. A more diverse antimicrobial activity (sactipeptides, microcins), production of secondary metabolites (siderophores and arylpolyenes), stress response and adaptation (bioluminescence, sodium transporters, catalase, high affinity for oxygen cytochrome cbb3 oxidase, DMSO reductase and proton translocating NADH dehydrogenase) is predicted compared to the other species. was divided into two clades based on source of isolation correlating with phylogeny and distribution of several traits. The species shows traits common to the other two species, similar carbon utilization/transport gene conservation as for the meat-isolated strains, and predicted utilization of marine-common DMSO and flagellar cluster for the sea-isolated strains. Results additionally suggest that photobacteria are highly prone to horizontal acquisition/loss of genetic material and genetic transduction, and that it might be a strategy for increasing the frequency of strain- or species-specific features that offers a growth/competition advantage.
PubMed: 34950912
DOI: 10.1016/j.crmicr.2021.100087 -
Frontiers in Microbiology 2022Decapod iridescent virus 1 (DIV1) has caused severe economic losses in shrimp aquaculture. So far, Researchs on DIV1-infected shrimp have mainly focused on the hemocytes...
INTRODUCTION
Decapod iridescent virus 1 (DIV1) has caused severe economic losses in shrimp aquaculture. So far, Researchs on DIV1-infected shrimp have mainly focused on the hemocytes immune response, while studies on the host-intestine microbiota interactions during DIV1 infection have been scarce.
METHODS
This study determined the lethal concentration 50 (LC) of DIV1 to , preliminarily determining that could serve as a susceptible object for DIV1. The interactions and responses between the immune and intestine microbiota of shrimp under DIV1 infection were also investigated.
RESULTS AND DISCUSSION
DIV1 infection decreases intestine bacterial diversity and alters the composition of intestine microbiota. Specifically, DIV1 infection decreases the abundance of potentially beneficial bacteria (Bacteroidetes, Firmicutes, and Actinobacteria), and significantly increases the abundance of pathogenic bacteria such as and , thereby increasing the risk of secondary bacterial infections. The results of PICRUSt functional prediction showed that altered intestine microbiota induces host metabolism disorders, which could be attributed to the bioenergetic and biosynthetic requirements for DIV1 replication in shrimp. The comparative transcriptomic analysis showed that some metabolic pathways related to host immunity were significantly activated following DIV1 infection, including ncRNA processing and metabolic process, Ascorbate and aldarate metabolism, and Arachidonic acid metabolism. may against DIV1 infection by enhancing the expression of some immune-related genes, such as Wnt16, heat shock protein 90 (Hsp90) and C-type lectin 3 (Ctl3). Notably, correlation analysis of intestinal microbial variation with host immunity showed that expansion of pathogenic bacteria ( and ) in DIV1 infection could increased the expression of NF-κB inhibitors cactus-like and Toll interacting protein (Tollip), which may limit the TLR-mediated immune response and ultimately lead to further DIV1 infection.
SIGNIFICANCE AND IMPACT OF THE STUDY
This study enhances our understanding of the interactions between shrimp immunity and intestinal microbiota. The ultimate goal is to develop novel immune enhancers for shrimp and formulate a safe and effective DIV1 defense strategy.
PubMed: 36713173
DOI: 10.3389/fmicb.2022.1097931 -
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 -
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 -
Frontiers in Nutrition 2022Herein, we present a method for producing water-soluble polysaccharides (WSPs) by co-culture fermentation of straw and shrimp shells. The chitin-degrading strain was...
Herein, we present a method for producing water-soluble polysaccharides (WSPs) by co-culture fermentation of straw and shrimp shells. The chitin-degrading strain was isolated and genotypically identified as the non-pathogen sp. LYM-1 in this study. sp. LYM-1 and 2012 could coexist without antagonism. WSPs concentrations were higher in co-culture fermentations of sp. LYM-1 and 2012 (PsL/AP-WSPs) compared to monocultures (PsL-WSPs and AP-WSPs). FTIR was used to examine the polysaccharide properties of three WSP fractions. The monosaccharide compositions of three WSPs fractions were primarily composed of mannose, ribose, glucosamine, glucose, galactose, and arabinose with varying molecular weights and molar ratios according to HPLC analysis. PsL/AP-WSPs showed better scavenging effects on DPPH, ABTS, and OH free radicals, demonstrating the application potential of PsL/AP-WSPs from straw and shrimp shells. The maximum yield obtained under optimum conditions (fermentation time of 6 days, temperature of 31°C, inoculum concentration of 10% (w/v), and inoculum composition of 2:1) was 5.88 ± 0.40 mg/mL, based on the PsL/AP-WSPs production optimization by orthogonal design. The results suggest that an environmentally friendly approach for WSPs production from agro-food wastes straw and shrimp shells was developed.
PubMed: 36479299
DOI: 10.3389/fnut.2022.1047932 -
Applied and Environmental Microbiology Apr 2018Symbiotic microorganisms have been found in the hemolymph (blood) of many aquatic invertebrates, such as crabs, shrimp, and oysters. Hemolymph is a critical site in the...
Symbiotic microorganisms have been found in the hemolymph (blood) of many aquatic invertebrates, such as crabs, shrimp, and oysters. Hemolymph is a critical site in the host immune response. Currently, studies on hemolymph microorganisms are mostly performed with culture-dependent strategies using selective media (e.g., thiosulfate-citrate-bile salts-sucrose [TCBS], 2216E, and LB) for enumerating and isolating microbial cells. However, doubts remain about the "true" representation of the microbial abundance and diversity of symbiotic microorganisms in hemolymph, particularly for uncultivable microorganisms, which are believed to be more abundant than the cultured microorganisms. To explore this, we developed a culture-independent cell extraction method for separating microbial cells from the hemolymph of three aquatic invertebrates ( [mud crab], [whiteleg shrimp], and [Portuguese oysters]) involving filtration through a 5-μm-pore-size mesh filter membrane (the filtration method). A combination of the filtration method with fluorescence microscopy and high-throughput sequencing technique provides insight into the abundances and diversity of the total microbiota in the hemolymph of these three invertebrates. More than 2.6 × 10 cells/ml of microbial cells dominated by and , and , and and were detected in the hemolymph of , , and , respectively. A parallel study for investigating the hemolymph microbiomes by comparing the filtration method and a culture-dependent method (the plate count method) showed significantly higher microbial abundances (between 26- and 369-fold difference; < 0.05) and less biased community structures of the filtration method than those of the plate count method. Furthermore, hemolymph of the three invertebrates harbored many potential pathogens, including , , and species. Finally, the filtration method provides a solution that improves the understanding of the metabolic functions of uncultivable hemolymph microorganisms (e.g., metagenomics) devoid of host hemocyte contamination. Microorganisms are found in the hemolymph of invertebrates, a critical site in the host immune response. Currently, studies on hemolymph microorganisms are mostly performed with culture-dependent strategies. However, doubts remain about the "true" representation of the hemolymph microbiome. This study developed a culture-independent cell extraction method that could separate microbial cells from the hemolymph of three aquatic invertebrates (, , and ) based on filtration through a 5-μm-pore-size mesh filter membrane (the filtration method). A combination of the filtration method with fluorescence microscopy and a high-throughput sequencing technique provides insight into the abundances and diversity of the total microbiota in the hemolymph of these three invertebrates. Our results demonstrate that the hemolymph of aquatic invertebrates harbors a much higher microbial abundance and more distinct microbial community composition than previously estimated. Furthermore, this work provides a less biased solution for studying the metabolic functions of uncultivable hemolymph microbiota devoid of host hemocyte contamination.
Topics: Analytic Sample Preparation Methods; Animals; Brachyura; Crassostrea; Hemolymph; Microbiota; Penaeidae
PubMed: 29453260
DOI: 10.1128/AEM.02824-17 -
International Journal of Molecular... Jul 2022The evaluation of temperature effects on the structure and function of enzymes is necessary to understand the mechanisms underlying their adaptation to a constantly...
The evaluation of temperature effects on the structure and function of enzymes is necessary to understand the mechanisms underlying their adaptation to a constantly changing environment. In the current study, we investigated the influence of temperature variation on the activity, structural dynamics, thermal inactivation and denaturation of and luciferases belonging to different subfamilies, as well as the role of sucrose in maintaining the enzymes functioning and stability. We used the stopped-flow technique, differential scanning calorimetry and molecular dynamics to study the activity, inactivation rate, denaturation and structural features of the enzymes under various temperatures. It was found that luciferase resembles the properties of cold-adapted enzymes with high activity in a narrow temperature range and slightly lower thermal stability than luciferase, which is less active, but more thermostable. Differences in activity at the studied temperatures can be associated with the peculiarities of the mobile loop conformational changes. The presence of sucrose does not provide an advantage in activity but increases the stability of the enzymes. Differential scanning calorimetry experiments showed that luciferases probably follow different denaturation schemes.
Topics: Luciferases; Luciferases, Bacterial; Structure-Activity Relationship; Sucrose; Temperature
PubMed: 35897698
DOI: 10.3390/ijms23158119