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Polybutylene succinate (PBS) is an eco‐friendly green plastic. However, PBS was shown as being non‐biodegradable in marine environments, and up until now, only a limited number of PBS‐degrading marine microbes have been discovered. We first set up in vitro PBS‐ and PBSA (polybutylene succinate adipate)‐plastispheres to characterize novel PBS‐degrading marine microbes. Microbial growth and oxygen consumption were observed in both PBS‐ and PBSA‐plastispheres enriched with natural seawater collected from Usujiri, Hokkaido, Japan, and Vibrionaceae and Pseudoalteromonadaceae were significantly enriched on these films. Further gene identification indicated that vibrios belonging to the Gazogenes clade possess genes related to a PBS degrading enzyme (PBSase). The PBS degradation assay for six Gazogenes clade vibrios identified Vibrio ruber, Vibrio rhizosphaerae, and Vibrio spartinae as being capable of degrading PBS. We further identified the gene responsible for PBSase from the type strain of V. ruber, and the purified recombinant vibrio PBSase was found to have low‐temperature adaptation and was active under high NaCl concentrations. We also provided docking models between the vibrio PBSase and PBS and PBSA units to show how vibrio PBSase interacts with each substrate compared to the Acidovorax PBSase. These results could contribute to a more sustainable society through further utilization of PBS in marine environments and plastic recycling. [ABSTRACT FROM AUTHOR]

The Splendidus clade is the largest clade in Vibrionaceae, and its members are often related to mortality of marine animals with huge economic losses. The molecular bases of their pathogenicity and virulence, however, remain largely unknown. In particular, the complete genome sequences of the Splendidus clade species are rarely registered, which is one of the obstacles to predict core and/or unique genes responsible for their adaptation and pathogenicity, and to perform a fine scale meta‐transcriptome during bacterial infection to their hosts. In this study, we obtained the complete genomes of all type strains in the Splendidus clade and revealed that (1) different genome sizes (4.4–5.9 Mb) with V. lentus the biggest and most of them had several big plasmids, likely because of the different features on mobilome elements; (2) the Splendidus clade consists of 19 species except V. cortegadensis, and 3 sub‐clades (SC) were defined with the 15 most closely related members as SC1; (3) different carbohydrate degradation preferences may be the result of environmental adaptation; and (4) a broad prediction of virulence factors (VFs) revealed core and species unique VF genes. [ABSTRACT FROM AUTHOR]

To fill in the gaps in knowledge as to how individual sea cucumber Apostichopus japonicus behave consuming eukaryotic food sources in natural environments, eukaryotic communities in the faeces of sea cucumbers and sediments were analysed through one whole year based on 16S rRNA gene sequencing of the organelle genomes. A total of 390 eukaryotic features were obtained, and 99.7% of the features were assigned to chloroplasts. The eukaryotic communities in faeces and sediments showed seasonal fluctuations through one whole year based on Bray‐Curtis distance and community composition. Comparison of eukaryotic communities between faeces and sediments showed that 12 families including Chaetocerotaceae and Laminariaceae were more abundant in faeces than in sediments, suggesting that sea cucumbers may choose sediment containing these algal taxa more often compared with others in natural environments. All features of Laminariaceae were assigned to Saccharina japonica, which is consistent with the fact that this alga is one of the most suitable diets in the aquaculture of A. japonicus. Assessments of individual 16S amplicon sequences of both faecal and sediment samples could be an alternative tool to help us understand dynamic feeding behaviours of sea cucumber populations in contributing to bioresource conservation and development of a superior approach to aquaculture. [ABSTRACT FROM AUTHOR]

Summary: Members of the family Vibrionaceae are generally found in marine and brackish environments, playing important roles in nutrient cycling. The Rumoiensis clade is an unconventional group in the genus Vibrio, currently comprising six species from different origins including two species isolated from non‐marine environments. In this study, we performed comparative genome analysis of all six species in the clade using their complete genome sequences. We found that two non‐marine species, Vibrio casei and Vibrio gangliei, lacked the genes responsible for algal polysaccharide degradation, while a number of glycoside hydrolase genes were enriched in these two species. Expansion of insertion sequences was observed in V. casei and Vibrio rumoiensis, which suggests ongoing genomic changes associated with niche adaptations. The genes responsible for the metabolism of glucosylglycerate, a compound known to play a role as compatible solutes under nitrogen limitation, were conserved across the clade. These characteristics, along with genes encoding species‐specific functions, may reflect the habit expansion which has led to the current distribution of Rumoiensis clade species. Genome analysis of all species in a single clade give us valuable insights into the genomic background of the Rumoiensis clade species and emphasize the genomic diversity and versatility of Vibrionaceae. [ABSTRACT FROM AUTHOR]

Summary: Deposit‐feeding sea cucumbers repeat ingestion of sediments and excretion of faeces daily and consequently increase bacterial abundance in sediments and promote organic matter mineralization. Such ecological roles are expected to be collaborative activities of sea cucumbers and the gut microbiota. Here, we performed a spatiotemporally broad 16S rRNA gene analysis using 109 samples from sea cucumber faeces and habitat sediments to explore potential contribution of their gut microbiota to the ecological roles. Most operational taxonomic units (OTUs) observed in the faecal samples were shared with the sediment samples, nevertheless faecal and sediment microbiota differed from each other in UniFrac analysis. Lower bacterial diversity and increased relative abundance of specific OTUs in the faecal microbiota strongly suggest selective enrichment of ingested sediment microbiota in their guts. Interestingly, representative faecal OTUs were more abundant in sea cucumber‐populated sediments than in un‐inhabited sediments, indicating bacteria selectively enriched in the guts were spread on ambient sediments via faeces. Moreover, the predicted microbial community metabolic potential showed a higher abundance of genes related to carbohydrate and xenobiotics metabolisms in faeces than in sediments. Our study suggests the repeated selective enrichment transforms ambient sediment microbial communities and maintains the host's ecological roles by promoting organic matter mineralization. [ABSTRACT FROM AUTHOR]

Vibrio infections are common among marine fish and lead to serious problems in the aquaculture sector. This study reports a recent occurrence of Vibrio species (spp.) isolated from cultured groupers in Peninsular Malaysia using the gyrB and pyrH genes. A total of 147 Vibrio strains were successfully isolated from 77 (64%) groupers using culture method and subjected to gyrB and pyrH sequencing for species identification and confirmation. Results showed that 89% of Vibrio strains were identified and clustered to six groups of Vibrio spp., while 11% were not clustered to any Vibrio spp. using the gyrB sequences. Meanwhile, by analysis of the pyrH sequences all the 147 Vibrio strains (100%) were successfully identified and clustered into 11 groups of Vibrio spp., including the gyrB non‐identified strains. The pyrH gene provides a better resolution for identification of Vibrio spp. compared with the gyrB gene. Thus, the pyrH gene was more suitable for a rapid determination of Vibrio spp. distribution in Peninsular Malaysia. Using the pyrH gene, our study found higher prevalence of Vibrio vulnificus (33%), V. alginolyticus (24%) and V. parahaemolyticus (22%), followed by V. rotiferianus (5%), V. harveyi (3%), V. tubiashii (2%), V. campbellii (2%), V. ponticus (1%), V. diabolicus (1%), V. owensii (1%) and others Vibrio sp. (7%). Thus, the results of this study revealed that the occurrence of pathogenic vibrios among grouper fish is still high in Malaysian aquaculture. In addition, the pyrH gene was proved as a suitable marker for rapid identification of Vibrio species compared with the gyrB gene. [ABSTRACT FROM AUTHOR]

Vibrio harveyi is an emerging pathogen that causes mass mortality in a wide variety of marine animal species; however, it is still unclear which environmental determinants correlate V. harveyi dynamics and the bacterium-mediated death of marine animal life. We conducted a correlation analysis over a 5-year period (2003–2007) analysing the following data: V. harveyi abundance, marine animal mortality and environmental variables (seawater temperature, salinity, pH, chlorophyll a, rainfall and total viable bacterial counts). The samples were collected from a coastal area in northern Japan, where deaths of a marine gastropod species ( Haliotis discus hannai) have been reported. Our analysis revealed significant positive correlations between average seawater temperature and average V. harveyi abundance ( R = 0.955; P < 0.05), and between average seawater temperature and V. harveyi-mediated abalone death ( R = 0.931; P < 0.05). Based on the regression model, n°C rise in seawater temperature gave rise to a 21 n-fold increase in the risk of mortality caused by V. harveyi infection. This is the first report providing evidence of the strong positive correlation between seawater temperature and V. harveyi-mediated death of marine species. [ABSTRACT FROM AUTHOR]

The article discusses the results of a study on the characterization of fish myofibrillar protein by conjugation with alginate oligosaccharide prepared using recombinant alginate lyase. The researchers found that the production of alginate lyase using genetically modifies Escherischia coli was superior to the purification of alginate lyase from a culture medium if Pseudoalteromonas elyakovii on production efficiency.