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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 -
Animal Nutrition (Zhongguo Xu Mu Shou... Jun 2022The utilization efficiency of soy protein is affected by its 2 anti-nutritional substances-the antigens β-conglycinin and glycinin. This study investigated their...
The utilization efficiency of soy protein is affected by its 2 anti-nutritional substances-the antigens β-conglycinin and glycinin. This study investigated their effects on the growth performance, intestinal immune defense, and microbiome in juvenile pearl gentian groupers (♀ × ♂). Three isonitrogenous and isolipidic diets were formulated containing fishmeal supplemented with 70 g/kg β-conglycinin or 100 g/kg glycinin, or no supplementation (control). Each experimental diet was fed to quadruplicate groups with 30 fish in each tank for 8 weeks. Dietary inclusion of either β-conglycinin or glycinin significantly reduced weight gain and specific growth rates, and cell proliferation of the distal intestine. Histological evaluation of the intestine tract revealed the inflammation signs, characterized by reducing of plica height and width as well as the number of the goblet cells, and widening of the lamina propria. The group fed the β-conglycinin diet had reduced lysozyme activity, contents of immunoglobulin M and complements 3 and 4. Increased activities of caspase-3 and -9 were observed in the group fed the β-conglycinin diet compared to the other 2 groups. In the intestinal microbiota, the relative abundances of the potentially pathogenic genera and were significantly higher in the glycinin group than those in others. Therefore, the existence of soybean antigens (β-conglycinin or glycinin) could damage the structural integrity of the intestine, reduce immune defense, reshape the intestinal microbiome and, ultimately, impair growth in fish.
PubMed: 35600546
DOI: 10.1016/j.aninu.2021.11.001 -
International Journal of Food... Nov 2023The advent of high-throughput sequencing technologies in recent years has revealed the unexpected presence of genus Photobacterium within the chicken meat spoilage...
The advent of high-throughput sequencing technologies in recent years has revealed the unexpected presence of genus Photobacterium within the chicken meat spoilage ecosystem. This study was undertaken to decipher the occurrence, the growth patterns and the genotypic biodiversity of Photobacterium phosphoreum on chicken breast fillets stored aerobically at 4 °C through conventional microbiological methods and molecular techniques. Samples were periodically cultured on marine broth agar (MA; supplemented with meat extract and vancomycin) for the enumeration of presumptive bioluminescent Photobacterium spp. In total, 90 bioluminescent bacteria were recovered from the initial (time of first appearance), middle and end stages of storage. Concomitantly, 95 total psychrotrophic/psychrophilic bacteria were isolated from the same medium to assess the presence and diversity of non-luminous photobacteria. Genetic diversity between bioluminescent isolates was assessed with two PCR-based DNA fingerprinting methods, i.e. RAPD and rep-PCR. Moreover, the characterization of selected bacterial isolates at the genus and/or species level was performed by sequencing of the 16S rRNA and/or gyrB gene. Bioluminescent bacteria were scarcely encountered in fresh samples at population levels of ca. 2.0 log CFU/g, whilst total psychrotrophic/psychrophilic bacteria were found at levels of ca. 4.4 log CFU/g. As time proceeded and close to shelf-life end, bioluminescent bacteria were encountered at higher populations, and were found at levels of 5.3 and 7.0 log CFU/g in samples from the second and third batch, respectively. In the first batch their presence was occasional and at levels up to 3.9 log CFU/g. Accordingly, total psychrotrophic/psychrophilic bacteria exceeded 8.4 log CFU/g at the end of storage, suggesting the possible underestimation of bioluminescent populations following the specific cultivation conditions. Sequence analysis assigned bioluminescent isolates to Photobacterium phosphoreum, while genetic fingerprinting revealed high intra-species variability. Respectively, total psychrotrophs/psychrophiles were assigned to genera Pseudomonas, Shewanella, Psychrobacter, Acinetobacter, Vibrio and Photobacterium. Non-luminous photobacteria were not identified within the psychrotrophs/psychrophiles. Results of the present study reveal the intra- and inter-batch variability on the occurrence and growth responses of P. phosphoreum and highlight its potential role in the chicken meat spoilage consortium.
Topics: Animals; Chickens; Food Microbiology; Meat; Photobacterium; Random Amplified Polymorphic DNA Technique; RNA, Ribosomal, 16S; Vibrio
PubMed: 37517119
DOI: 10.1016/j.ijfoodmicro.2023.110334 -
International Journal of Food... Aug 2021Fresh meat is commonly packaged in modified atmosphere to decelerate spoilage processes. The applied gas mixture affects the growth of spoilage organisms and selectively...
Fresh meat is commonly packaged in modified atmosphere to decelerate spoilage processes. The applied gas mixture affects the growth of spoilage organisms and selectively shapes the spoilage community. In this study, we investigated the impact of O and CO on the growth of Photobacterium (P.) phosphoreum and P. carnosum strains in situ on chicken meat by packaging under different modified atmospheres (air, 70% O/30% CO, 70% N/30% CO, 100% N). Combination of 70% O and 30% CO resulted in significant growth reduction of the analyzed strains, suggesting inhibitory effects of both gases in combination. In contrast, 30% CO alone had only a minor effect and photobacteria are supposed to have a growth advantage over other meat spoilers in this atmosphere. Additionally, single growth of the strains in the different atmospheres was compared when challenged with the presence of Pseudomonas (Ps.) fragi or Brochothrix (B.) thermosphacta as prominent co-contaminants in different ratios (10:1, 1:1, 1:10). Presence of co-contaminants resulted in increased cell numbers of P. carnosum TMW2.2149 but reduced or unchanged cell numbers of P. phosphoreum TMW2.2103 in most packaging atmospheres. The initial ratio of photobacteria and co-contaminants defined the relative abundance during storage but did not change the type of the interaction. Our results suggest either a commensalistic (P. carnosum) or competitive interaction (P. phosphoreum) of photobacteria and co-contaminants on modified atmosphere packaged chicken, respectively. Furthermore, in a mix comprising seven prominent spoilers, strains of both Photobacterium species prevailed as a constant part of the spoilage microbiome during 7 days of refrigerated storage on chicken meat packaged under O/CO atmosphere.
Topics: Animals; Atmosphere; Bacteria; Carbon Dioxide; Chickens; Food Microbiology; Food Packaging; Microbial Interactions; Microbiota; Oxygen; Photobacterium; Poultry
PubMed: 34098468
DOI: 10.1016/j.ijfoodmicro.2021.109264 -
International Journal of Food... Nov 2022Pork preservation and cooking are common processes in food production. This study analyzed the influence of cinnamon essential oil nanoemulsions (CEON), ε-polylysine...
Influence of the combination of cinnamon essential oil nanoemulsions and epsilon-polylysine on microbial community and quality of pork during refrigerated period and radio frequency cooking.
Pork preservation and cooking are common processes in food production. This study analyzed the influence of cinnamon essential oil nanoemulsions (CEON), ε-polylysine (ε-PL) and CEON/ε-PL on microbial community and quality of pork during refrigerated storage and radio frequency (RF) cooking. Results showed that a stable CEON was prepared with soybean lecithin (oil: lecithin = 1:1 w/w). CEON and ε-PL inhibited the growth of total bacteria counts (TBC) of raw pork, and caused Salmonella reduction at refrigerated storage of 12 d. Photobacterium and Pseudomonas were dominant spoilage bacteria of raw pork during refrigerated period. The 0.25 % CEON and 0.125 % CEON + 0.25 % ε-PL had good antimicrobial effects against Photobacterium while 0.5 % ε-PL had a small effect. Pork treated by CEON and CEON/ε-PL had better freshness than control and ε-PL treated samples. RF cooking lowered cooking time compared to water bath cooking at 80 °C and a similar quality of cooked pork was observed. CEON/ε-PL promoted Salmonella and TBC inactivation during RF cooking. TVB-N content, pH, cooking loss and appearance of RF cooked pork were not influenced by the addition of CEON/ε-PL, but the odor was slightly affected. The hardness, springiness and chewiness were enhanced by the addition of CEON/ε-PL. The results revealed that CEON/ε-PL could be used in raw pork preservation and promote bacteria inactivation during RF cooking.
Topics: Animals; Anti-Infective Agents; Bacteria; Cinnamomum zeylanicum; Cooking; Food Microbiology; Food Preservation; Lecithins; Microbiota; Oils, Volatile; Polylysine; Pork Meat; Red Meat; Salmonella; Swine; Water
PubMed: 36063682
DOI: 10.1016/j.ijfoodmicro.2022.109911 -
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 -
Environmental Research Jan 2023The huge application of synthetic dyes caused a severe impact in the environment. In the present study, a physico-chemical strategy of heterogeneous-Fenton catalyzed by...
The huge application of synthetic dyes caused a severe impact in the environment. In the present study, a physico-chemical strategy of heterogeneous-Fenton catalyzed by the natural ferrous ore has been established for toxic chemical degradation, of which the complex and high-expense repetitive pH adjustment procedures were escaping. And this natural heterogeneous catalyst also could be recycled and sustainable for toxic substances treatment involved in synergetic adsorption and oxidation. The siderite, served as an adsorbent and catalyst for the degradation of methylene blue (MB). Siderite exhibited a better adsorption capacity with a saturated adsorption capacity of ∼11.08 mg/g. Batch adsorption experiments have verified that adsorption rate and adsorption equilibrium followed pseudo-second-order rate model and Langmuir isotherm equation, respectively. The combination with HO, showed significant enhancement of MB degradation without any pH adjustment. The effect of siderite dosage, HO dosage, MB concentration, initial pH, and reaction temperature on MB degradation was investigated, which also has indicated the excellent catalytic performance of siderite. About 99.71% of MB was degraded in 480 min with initial pH of 7.0, reaction temperature of 25 °C, siderite, and HO dosage of 2.5 g/L and 122.38 mM, respectively. It was found that siderite could be reused and remained high degradation efficiency on MB after 5 times reutilization, which also could demonstrate the sustainable and effective process to degrade organic pollution. The generation of reactive species including ·OH and O2·- have been confirmed based on scavenger test and electron spin resonance (ESR) analysis, which was dominated by heterogeneous reaction. The possible degradation mechanisms of MB have been predicted based on spectrum scanning and GC-MS analysis. Moreover, acute toxicity assessment with marine photobacterium Vibrio fisheri was conducted to investigate the toxicity change in the adsorption/oxidation coupled process. This sustainable heterogeneous-Fenton technology has been verified as a promising and applicable process for toxic organic chemicals removal due to effective mineralization and detoxification assisted with the natural ore mineral through the simple operation and mild condtions.
Topics: Methylene Blue; Hydrogen Peroxide; Water Pollutants, Chemical; Kinetics; Adsorption; Catalysis
PubMed: 36395859
DOI: 10.1016/j.envres.2022.114819 -
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 -
Antioxidants (Basel, Switzerland) Jun 2022Phospholipids have an important antioxidant effect on animals. The effects of different dietary phospholipid sources on the growth, antioxidant activity, immunity, and...
Phospholipids have an important antioxidant effect on animals. The effects of different dietary phospholipid sources on the growth, antioxidant activity, immunity, and gut microbiota of female broodstock of Pacific white shrimp were investigated. Four isoproteic and isolipid semi-purified diets containing 4% soybean lecithin (SL), egg yolk lecithin (EL), or krill oil (KO) and a control diet without phospholipid supplementation were fed to female broodstock of (34.7 ± 4.2 g) for 28 days. The growth performance, antioxidative capacity, and innate immunity of the female broodstock fed phospholipid supplemented diets were improved regardless of sources compared with the control shrimp. The effects on growth and antioxidant capacity in female shrimp fed the KO diet were highest. The innate immunity of female shrimp fed the EL and KO diets were significantly higher than shrimp fed the SL diet. Dietary phospholipid supplementation increased gut microbiota diversity and richness, and the Chao1 and ACE values in the KO group were significantly higher than in the control group. The richness of Proteobacteria, , and decreased, whereas the richness of Firmicutes and Bacteroidetes increased in the shrimp fed the KO diet compared with the shrimp fed the SL and EL diets. The interactions of gut microbiota in shrimp fed the KO diet were the most complex, and the positive interaction was the largest among all the treatments. The functional genes of gut microbiota in shrimp fed the KO diet were significantly enriched in lipid metabolism and terpenoid/polyketide metabolism pathways. Spearman correlation analysis showed that had significantly positive correlations with antioxidant activity (total antioxidant capacity, superoxide dismutase, glutathione peroxidase), immune enzyme activity (phenoloxidase and lysozyme), and immune gene expression (C-type lectin 3, Caspase-1). All findings suggest that dietary phospholipids supplementation can improve the growth and health status of female broodstock. Krill oil is more beneficial in improving the antioxidant capacity and innate immunity than other dietary phospholipid sources. Furthermore, krill oil can help establish the intestinal immune barrier by increasing the richness of and promote the growth of female shrimp. may be involved in iron metabolism to improve the antioxidant capacity of female shrimp.
PubMed: 35740040
DOI: 10.3390/antiox11061143 -
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