Discovery, diversity and functional associations of crAss-like phages in human gut metagenomes from four Dutch cohorts

The crAss-like phages are a diverse group of related viruses that includes one of the most abundant viruses of the human gut. To explore their diversity and functional role in human population and clinical cohorts, we analyzed gut metagenomic data collected from more than 2000 individuals from the Netherlands. We discovered 125 novel species-level and 32 novel genus-level clusters of crAss-like phages, all belonging to five previously recognized groups associated with the human gut. Analysis of their genomic features revealed that closely related crAss-like phages can possess strikingly divergent regions responsible for transcription, presumably acquired through recombination. Prediction of crAss-like phage hosts pointed primarily to bacteria of the phylum Bacteroidetes, consistent with previous reports. Finally, we explored the temporal stability of crAss-like phages over a 4-year period and identified associations between the abundance of crAss-like phages and several human phenotypes, including depletion of crAss-like phages in inflammatory bowel disease patients.

Assessment of Megadenus holothuricola Rosén, 1910 (Eulimidae), an endoparasite of Holothuria mexicana Ludwig, 1875 (Holothuriidae) in the southern Gulf of Mexico and the description a new species

As part of a study on holothurians from the southern Gulf of Mexico, some Holothuria mexicana Ludwig, 1875 were obtained for gut analysis. In two of them, a couple of eulimids were located inside the main tube of the respiratory tree. They were identified as Megadenus holothuricola Rosén, 1910, described from the Bahamas Islands, based on five specimens attached to the respiratory tree of H. mexicana. The original description was brief with few details, the type material is lost, and the species has not been found again. In this contribution, this species is confirmed for Campeche Bay, Mexico. The adult shell is globular to conical, transparent, thin, and fragile. Megadenus smithisp. nov. from Palmyra Atoll, Central Pacific is described based on adult specimens. It differs from its congeneric species in its more robust shell, the pseudopallium does not cover the shell, and its short and contracted proboscis forms a thick disc. Further research on these eulimid parasites is now complicated in the southern Gulf of Mexico because of the holothurian population collapse due to over-exploitation of the fishery.

Studies on Tropics of Fish Along Upper Tungabhadra Channel, Ballari District, Karnataka

Gut analysis is the tool to understand the feeding patterns of fishes and is an important aspect of fisheries management. It also provides the basis for understanding trophic interactions in aquatic food webs and to investigate the most frequently consumed prey or to determine the relative importance of different food types to fish nutrition. In the present study the gut content analysis was performed in Garra, Gobi, Notopterus and Tilapia fishes collected from Tungabhadra upper irrigation channel at Ballari, Karnataka.Bacillariophyceae showed maximum number in all the four fish species. Over all it showed 40% followed by Detritus (30%), Chlorophyceae (17%), Cyanophyceae(7%) and Zooplankton (6%). Among fishes Garrashowed maximum food items (2272) followed by Glossogobiusgiuris(1538), Notopterusnotopterus (996) and Oreochromismossambicus (769). The relative abundance of food items in the guts also revealed the Garragotylastenorhynchus Oreochromismossambicus. The variation is due to availability of foodorganisms during the study period and anthropogenic influence on channel water.

Jenis-Jenis Pakan Alami Leptobarbus melanopterus di Taman Nasional Danau Sentarum Kabupaten Kapuas Hulu

As the endemic fish of Danau Sentarum National Park, peam fish or Leptobarbus melanopterus had environmental problem such as overfishing due which threaten either juvenile or adult fish. These conditions were feared will led L. melanopterus population decrease in future if there is no sustainable management such as aquaculture. This research aims to identify the natural foods of L. melanopterus. Sixty four samples of L. melanopterus were collected through purposive sampling method. The results of gut analysis were found 17 genera of phytoplankton, 4 genera of zooplankton, 1 plant, and 1 Insecta. Zygnematophyceae had the most various genera which consisted of 7 genera while Ulvophyceae and Xanthophyceae only had 1 genera each of them. The natural food of L. melanopterus can be used as preliminary data for the application of aquaculture in the future.

Crustacean prey in the diet of fishes from deep waters of the Eastern Ionian Sea

The gut analysis of 26 fish species caught in the deep waters of the Eastern Ionian Sea showed that crustaceans were a substantial resource for fish found in deep- water environments, comprising 37 crustacean taxa. Among all species examined, 77% included crustaceans in their guts. Dendrobranchiata/Caridea shrimps were the most frequent crustacean prey found in the guts of almost all examined fishes, with high values of relative abundance (N%). Season (summer, autumn) and fish behaviour (demersal, benthic) were not found to affect the diet of the examined fish species. Galeus melastomus could be considered to be a separate case showing the most diverse diet comprising all the crustacean groups. Differences in the proportion of the main crustacean categories consumed by the examined fish species were observed. The low richness and preference towards specific crustacean taxa or different crustacean species could be considered as an indication of interspecific competition for the same food resource in the oligotrophic waters of the Eastern Mediterranean. The occurrence of different crustacean taxa in the gut of some species through the analysed seasons, could be related to differences in prey availability or to selective preference for certain prey which in turn could be linked to different energetic requirements for growth and reproduction of predators.