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Environmental Microbiome Oct 2023Coral reefs are one of the most biodiverse and productive ecosystems, providing habitat for a vast of species. Reef-building scleractinian corals with a symbiotic...
BACKGROUND
Coral reefs are one of the most biodiverse and productive ecosystems, providing habitat for a vast of species. Reef-building scleractinian corals with a symbiotic microbiome, including bacteria, archaea, viruses and eukaryotic microbes, are referred to coral holobionts. Among them, coral diseases, mainly caused by Vibrio spp., have significantly contributed to the loss of coral cover and diversity. Habitat filtering across the globe has led to a variety structure of marine bacterial communities. Coral species, quantity and characteristics are significant differences between the Xisha Islands and Daya Bay (Guangdong Province). Thus, the Vibrio communities may be distinct between coral rich and poor areas.
RESULTS
Through comparison of Vibrio dynamics between coral-rich (Xisha Islands) and coral-poor (Daya Bay) locations, we uncovered differences in Vibrio abundance, diversity, community composition and assembly mechanisms associated with corals. The higher abundance of Vibrio in coral rich areas may indicate a strong interaction between vibrios and corals. V. campbellii, Paraphotobacterium marinum and V. caribbeanicus were widely distributed in both coral rich and poor areas, likely indicating weak species specificity in the coral-stimulated growth of Vibrio. Random-forest prediction revealed Vibrio species and Photobacterium species as potential microbial indicators in the coral rich and coral poor areas, respectively. Ecological drift rather than selection governed the Vibrio community assembly in the Xisha Islands. Comparatively, homogenizing selection was more important for the Daya Bay community, which may reflect a role of habitat filtration.
CONCLUSION
This study revealed the different distribution pattern and assembly mechanism of Vibrio spp. between coral rich and poor areas, providing the background data for the research of Vibrio community in coral reef areas and may help the protection of coral reef at the biological level. The main reasons for the difference were different number and species of corals, environmental (e.g., temperature) and spatial factors. It reflected the strong interaction between Vibrio and corals, and provided a new perspective for the investigation of Vibrio in coral reef ecosystem.
PubMed: 37872593
DOI: 10.1186/s40793-023-00532-7 -
Frontiers in Microbiology 2023Recirculating aquaculture systems (RAS) pose unique challenges in microbial community management since they rely on a stable community with key target groups, both in...
Recirculating aquaculture systems (RAS) pose unique challenges in microbial community management since they rely on a stable community with key target groups, both in the RAS environment and in the host (in this case, ). Our goal was to determine how much of the sole microbiome is inherited from the egg stage, and how much is acquired during the remainder of the sole life cycle in an aquaculture production batch, especially regarding potentially probiotic and pathogenic groups. Our work comprises sole tissue samples from 2 days before hatching and up to 146 days after hatching (-2 to 146 DAH), encompassing the egg, larval, weaning, and pre-ongrowing stages. Total DNA was isolated from the different sole tissues, as well as from live feed introduced in the first stages, and 16S rRNA gene was sequenced (V6-V8 region) using the Illumina MiSeq platform. The output was analysed with the DADA2 pipeline, and taxonomic attribution with SILVAngs version 138.1. Using the Bray-Curtis dissimilarity index, both age and life cycle stage appeared to be drivers of bacterial community dissimilarity. To try to distinguish the inherited (present since the egg stage) from the acquired community (detected at later stages), different tissues were analysed at 49, 119 and 146 DAH (gill, intestine, fin and mucus). Only a few genera were inherited, but those that were inherited accompany the sole microbiome throughout the life cycle. Two genera of potentially probiotic bacteria ( and ) were already present in the eggs, while others were acquired later, in particularly, forty days after live feed was introduced. The potentially pathogenic genera and were inherited from the eggs, while and seemed to be acquired at 49 and 119 DAH, respectively. Significant co-occurrence was found between and both and . On the other hand, significantly negative correlations were detected between and , , and . Our work reinforces the importance of life cycle studies, which can contribute to improve production husbandry strategies. However, we still need more information on this topic as repetition of patterns in different settings is essential to confirm our findings.
PubMed: 37434707
DOI: 10.3389/fmicb.2023.1188876 -
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 -
Applied and Environmental Microbiology Jul 2023Coral reefs are among the most biodiverse ecosystems, providing habitats for various organisms. Studies on coral bleaching have been increasing recently, but little is...
Coral reefs are among the most biodiverse ecosystems, providing habitats for various organisms. Studies on coral bleaching have been increasing recently, but little is known about the distribution and community assembly of coral pathogenic bacteria (e.g., several species). We elucidated the distribution pattern and interaction relationships of total bacteria and spp. in sediments from the Xisha Islands, which are characterized by their high coverage and diversity of coral resources. spp. showed significantly higher relative abundance values in the Xisha Islands (1.00 × 10 copies/g) than in other areas (approximately 1 × 10 to 9.04 × 10 copies/g), indicating that the coral bleaching event of 2020 may have promoted the bloom of vibrios. A spatial shift in community composition was observed between the northern (Photobacterium rosenbergii and Vibrio ponticus) and southern (Vibrio ishigakensis and Vibrio natriegens) sites, accompanied by a clear distance-decay pattern. The spatial distance and coral species (e.g., and ) had much greater correlations with the community than did environmental factors. However, complex mechanisms may exist in the community assembly of spp. due to the large proportion of unexplained variation. Stochastic processes may play an important role, as shown by the neutral model. Vibrio harveyi had the highest relative abundance (77.56%) and niche breadth, compared to other species, and it was negatively correlated with Acroporidae, likely reflecting its strong competitive ability and adverse effects on specific corals. Our study provides insights into the bloom and underlying assembly mechanisms of sedimentary vibrios in the Xisha Islands, thereby contributing to identify the potential indicator of coral bleaching and provide inspiration for the environmental management of coral reef areas. Coral reefs exert important roles in maintaining the sustainability of marine ecosystems but decline worldwide due to various drivers, especially pathogenic microorganisms. Here, we investigated the distribution pattern and interactions of total bacteria and spp. in the sediments from Xisha Islands during the coral bleaching event of 2020. Our results showed that the abundances of (1.00 × 10 copies/g) were high across the whole sites, indicating the bloom of sedimentary spp. Coral pathogenic species were abundant in the sediments, likely reflecting adverse effects on several kinds of corals. The compositions of the spp. were separated by geographical location, which was mainly attributable to the spatial distance and coral species. Overall, this work contributes by providing evidence for the outbreak of coral pathogenic vibrios. The pathogenic mechanism of the dominant species (especially V. harveyi) should be comprehensively considered by laboratory infection experiments in the future.
Topics: Animals; Ecosystem; Coral Bleaching; Islands; Coral Reefs; Anthozoa; Vibrio
PubMed: 37314342
DOI: 10.1128/aem.00543-23 -
Marine Environmental Research Apr 2024The New Zealand Greenshell™ mussel (Perna canaliculus) is an economically important aquaculture species. Prolonged increases in seawater temperature above mussel...
Interactive effects of elevated temperature and Photobacterium swingsii infection on the survival and immune response of marine mussels (Perna canaliculus): A summer mortality scenario.
The New Zealand Greenshell™ mussel (Perna canaliculus) is an economically important aquaculture species. Prolonged increases in seawater temperature above mussel thermotolerance ranges pose a significant threat to mussel survival and health, potentially increasing susceptibility to bacterial infections. Using challenge experiments, this study examined the combined effects of increased seawater temperature and bacterial (Photobacterium swingsii) infection on animal survival, haemocyte and biochemical responses of adult mussels. Mussels maintained at three temperatures (16, 20 and 24 °C) for seven days were either not injected (control), injected with sterile marine broth (injection control) or P. swingsii (challenged with medium and high doses) and monitored daily for five days. Haemolymph and tissue samples were collected at 24, 48, 72, 96, 120 h post-challenge and analysed to quantify bacterial colonies, haemocyte responses and biochemical responses. Mussels infected with P. swingsii exhibited mortalities at 20 and 24 °C, likely due to a compromised immune system, but no mortalities were observed when temperature was the only stressor. Bacterial colony counts in haemolymph decreased over time, suggesting bacterial clearance followed by the activation of immune signalling pathways. Total haemocyte counts and viability data supports haemocyte defence functions being stimulated in the presence of high pathogen loads at 24 °C. In the gill tissue, oxidative stress responses, measured as total antioxidant capacity and malondialdehyde (MDA) levels, were higher in infected mussels (compared to the controls) after 24h and 120h post-challenge at the lowest (16 °C) and highest temperatures (24 °C), indicating the presence of oxidative stress due to temperature and pathogen stressors. Overall, this work confirms that Photobacterium swingsii is pathogenic to P. canaliculus and indicates that mussels may be more vulnerable to bacterial pathogens under conditions of elevated temperature, such as those predicted under future climate change scenarios.
Topics: Animals; Temperature; Perna; Photobacterium; Immunity
PubMed: 38364448
DOI: 10.1016/j.marenvres.2024.106392 -
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 -
Foods (Basel, Switzerland) Jul 2023The aim of this study was to investigate the microbial and physico-chemical characteristics of cold smoked sea bass (CSSB), a novel italian fish product. The...
The aim of this study was to investigate the microbial and physico-chemical characteristics of cold smoked sea bass (CSSB), a novel italian fish product. The microbiological analyses showed the presence of bacterial contamination from the raw material, the environment, and the production process. The microbial spoilage population was dominated by lactic acid bacteria (LAB) associated with Gram-negative fermenting bacteria, including and psychrotrophic Enterobacteriaceae. and spp. were also present; in contrast, mould and yeast were not detected (<2 CFU/g). High levels (6-7 log CFU/g) of LAB and total bacteria count (TBC) were observed from day 45 of storage; however, their presence does not seem to have influenced the total volatile basic nitrogen (TVB-N), which always remained below 35 mg N/100 g. Consequently, the product is acceptable until day 60 of storage, considering that the malonaldehyde index (TBARS) was lower than 6.5 nmol/g. Pathogenic bacteria such as spp. and were not detected. Currently, there is a growing demand for seafood due to its high quality and nutritional value. Cold smoked sea bass offers a source of macro- and micronutrients essential for the proper functioning of the human body. It is also rich in protein and omega-3 fatty acids. The WHO and FAO evaluated the benefits and risks and concluded that there is convincing evidence of health benefits from fish consumption, such as a reduction in the risk of heart failure and improved neurodevelopment in infants and young children when fish is consumed by the mother before and during pregnancy. The CSSB analysed in this study demonstrated to have health benefits due to long-chain omega-3 PUFAs and other nutrients, such as proteins, minerals, and vitamin D, which are sometimes difficult to obtain from other sources. The results show that CSSB has a high nutritional value and excellent microbial quality.
PubMed: 37509776
DOI: 10.3390/foods12142685 -
Biology Dec 2023Salinity is an important environmental stress factor in mariculture. Shrimp intestines harbor dense and diverse microbial communities that maintain host health and...
Salinity is an important environmental stress factor in mariculture. Shrimp intestines harbor dense and diverse microbial communities that maintain host health and anti-pathogen capabilities under salinity stress. In this study, 16s amplicon and transcriptome sequencing were used to analyze the intestine of under low-salinity stress (15 ppt). This study aimed to investigate the response mechanisms of the intestinal microbiota and gene expression to acute low-salinity stress. The intestinal tissues of were analyzed using 16S microbiota and transcriptome sequencing. The microbiota analysis demonstrated that the relative abundances of and decreased significantly, whereas , , , , , , , and became the predominant communities. Transcriptome sequencing identified numerous differentially expressed genes (DEGs). The DEGs were clustered into many Gene Ontology terms and further enriched in some immunity- or metabolism-related Kyoto Encyclopedia of Genes and Genomes pathways, including various types of N-glycan biosynthesis, amino acid sugar and nucleotide sugar metabolism, and lysosome and fatty acid metabolism. Correlation analysis between microbiota and DEGs showed that changes in , , , and were positively correlated with immune-related genes such as peritrophin-1-like and mucin-2-like, and negatively correlated with caspase-1-like genes. Low-salinity stress caused changes in intestinal microorganisms and their gene expression, with a close correlation between them.
PubMed: 38132328
DOI: 10.3390/biology12121502 -
Foods (Basel, Switzerland) Dec 2023Cold-smoked salmon are ready-to-eat products that may support the growth of pathogenic during their long shelf-life. Consumption of such contaminated products can cause...
Cold-smoked salmon are ready-to-eat products that may support the growth of pathogenic during their long shelf-life. Consumption of such contaminated products can cause fatal listeriosis infections. Another challenge and potential risk associated with CS salmon is their high levels of sodium salt. Excess dietary intake is associated with serious health complications. In the present study, anti-listerial bacteriocin (nisin), P100 bacteriophages (Phageguard L, PGL) and fermentates (Verdad N6, P-NDV) were evaluated as commercial bio-preservation strategies for increased control of in standard (with NaCl) and sodium-reduced (NaCl partially replaced with KCl) CS salmon. Treatments of CS salmon with nisin (1 ppm) and PGL (5 × 10 pfu/cm) separately yielded significant initial reductions in (up to 0.7 log) compared to untreated samples. Enhanced additive reductions were achieved through the combined treatments of nisin and PGL. Fermentates in the CS salmon inhibited the growth of Listeria but did not lead to its eradication. The lowest levels of during storage were observed in nisin- and PGL-treated CS salmon containing preservative fermentates and stored at 4 °C, while enhanced growth was observed during storage at an abusive temperature of 8 °C. Evaluation of industry-processed standard and sodium-replaced CS salmon confirmed significant effects with up to 1.7 log reductions in levels after 34 days of storage of PGL- and nisin-treated CS salmon-containing fermentates. No differences in total aerobic plate counts were observed between treated (PGL and nisin) or non-treated standard and sodium-reduced CS salmon at the end of storage. The microbiota was dominated by but with a shift showing dominance of spp. and spp. in fermentate-containing samples. Similar and robust reductions in can be achieved in both standard and sodium-replaced CS salmon using the bio-preservation strategies of nisin, PGL and fermentates under various and relevant processing and storage conditions.
PubMed: 38137194
DOI: 10.3390/foods12244391 -
Scientific Reports Mar 2024It is widely believed that a significant portion of the gut microbiota, which play crucial roles in overall health and disease, originates from the food we consume....
It is widely believed that a significant portion of the gut microbiota, which play crucial roles in overall health and disease, originates from the food we consume. Sashimi is a type of popular raw seafood cuisine. Its microbiome, however, remained to be thoroughly explored. The objective of this study is to explore the microbiome composition in sashimi at the time when it is served and ready to be eaten. Specifically, our tasks include investigating the diversity and characteristics of microbial profiles in sashimi with respect to the fish types. We utilized the Sanger-sequencing based DNA barcoding technology for fish species authentication and next-generation sequencing for sashimi microbiome profiling. We investigated the microbiome profiles of amberjack, cobia, salmon, tuna and tilapia sashimi, which were all identified using the MT-CO1 DNA sequences regardless of their menu offering names. Chao1 and Shannon indexes, as well as Bray-Curtis dissimilarity index were used to evaluate the alpha and beta diversities of sashimi microbiome. We successfully validated our previous observation that tilapia sashimi has a significantly higher proportions of Pseudomonas compared to other fish sashimi, using independent samples (P = 0.0010). Salmon sashimi exhibited a notably higher Chao1 index in its microbiome in contrast to other fish species (P = 0.0031), indicating a richer and more diverse microbial ecosystem. Non-Metric Multidimensional Scaling (NMDS) based on Bray-Curtis dissimilarity index revealed distinct clusters of microbiome profiles with respect to fish types. Microbiome similarity was notably observed between amberjack and tuna, as well as cobia and salmon. The relationship of microbiome similarity can be depicted as a tree which resembles partly the phylogenetic tree of host species, emphasizing the close relationship between host evolution and microbial composition. Moreover, salmon exhibited a pronounced relative abundance of the Photobacterium genus, significantly surpassing tuna (P = 0.0079), observed consistently across various restaurant sources. In conclusion, microbiome composition of Pseudomonas is significantly higher in tilapia sashimi than in other fish sashimi. Salmon sashimi has the highest diversity of microbiome among all fish sashimi that we analyzed. The level of Photobacterium is significantly higher in salmon than in tuna across all the restaurants we surveyed. These findings provide critical insights into the intricate relationship between the host evolution and the microbial composition. These discoveries deepen our understanding of sashimi microbiota, facilitating our decision in selecting raw seafood.
Topics: Animals; Phylogeny; Microbiota; Gastrointestinal Microbiome; Salmon; Tuna; Seafood; Photobacterium; Pseudomonas
PubMed: 38443405
DOI: 10.1038/s41598-024-55938-1