Expression of GFSKLYFamide-like neuropeptide in the digestive system of the sea cucumber Holothuria scabra (Echinodermata)

Neuropeptides are key mediators of physiological processes in animals and a considerable amount of information has been accumulated on their diversity and functions across phyla. However, progress in echinoderm neurobiology has been much slower than others. The sea cucumber Holothuria scabra is an economically important tropical echinoderm species in which a neuropeptide is yet to be identified. This immunohistochemical study utilized antibody raised against GFSKLYFamide neuropeptide together with confocal laser scanning microscopy. GFSKLYFamide-like immunoreactivity was shown to be localized in the stomach and small intestines of H. scabra. This is the first report that provides evidence for the presence of GFSKLYFamide neuropeptide in the digestive tract of this species.Keywords: GFSKLYFamide, SALMFamides, immunohistochemistry, sea cucumber, Holothuria scabra

New Paradigms to Help Solve the Global Aquaculture Disease Crisis.

Published onlineJournal ArticleThis is the final version of the article. Available from Public Library of Science via the DOI in this record.n/aThe authors (GDS, KS) acknowledge funding administered by the British Council under the Newton Fund Researcher Links Programme, for a UK-Thailand bilateral workshop entitled "Scientific, technological and social solutions for sustainable aquaculture in Thailand: a key player in global aquatic food supply," Bangkok, March 2016. Further funding support is acknowledged from the European Commission (EC) and the UK Department for Environment, Food and Rural Affairs (Defra) under contracts C6928 and FB002 (to GDS and DB); from the Royal Society under a University Research Fellowship (to BAPW); and to the Agricultural Research Development Agency (ARDA) and National Research Council of Thailand (NRCT) (to KS, TWF, and OI). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript

N-hexanoyl-L-homoserine lactone-degrading Pseudomonas aeruginosa PsDAHP1 protects zebrafish against Vibrio parahaemolyticus infection

Four strains of N-hexanoyl-L-homoserine lactone (AHL)-degrading Pseudomonas spp., named PsDAHP1, PsDAHP2, PsDAHP3, and PsDAHP4 were isolated and identified from the intestine of Fenneropenaeus indicus. PsDAHP1 showed the highest AHL-degrading activity among the four isolates. PsDAHP1 inhibited biofilm-forming exopolysaccharide and altered cell surface hydrophobicity of virulent green fluorescent protein (GFP)-tagged Vibrio parahaemolyticus DAHV2 (GFP-VpDAHV2). Oral administration of PsDAHP1 significantly reduced zebrafish mortality caused by GFP-VpDAHV2 challenge, and inhibited colonisation of GFP-VpDAHV2 in the gills and intestine of zebrafish as evidence by confocal laser scanning microscope and selective plating. Furthermore, zebrafish receiving PsDAHP1-containing feed had increased phagocytic cells of its leucocytes, increased serum activities of superoxide dismutase and lysozyme. The results suggest that Pseudomonas aeruginosa PsDAHP1 could protect zebrafish from V. parahaemolyticus infection by inhibiting biofilm formation and enhancing defence mechanisms of the fish

Presence of GFSKLYFamide-like Neuropeptide in the Tentacles, Body Wall and Tube Foot of Holothuria scabra: Immunohistochemical Evidence

The neuropeptide GFSKLYFamide is a heptapeptide first isolated from the sea cucumber, Holothuria glaberimma. The holothurian body wall, tentacles and tube foot are important organs for locomotion, feeding and maintenance of homeostasis. This study was aimed at determining the localization of GFSKLYFamide in the tentacles, body wall and tube foot of Holothuria scabra. Ten male H. scabra weighing between 62g and 175g were used for this study. Using GFSKLYFamide polyclonal antibody and Alexa 488-conjugated goat anti-rabbit IgG as primary and secondary antibodies, respectively, indirect immunofluorescence method with confocal microscope imaging were used to localise GFSKLYFamide immunoreactivity in the tentacles, body wall and tube foot of H. scabra. The results indicate the presence of GFSKLYFamide-like neuropeptide in the epithelial layers of the tentacles, body wall and tube foot. GFSKLYFamide-like immunoreactivity was also detected within the connective tissue layer of the tentacles and tube foot