The abundance, distribution and diversity of epibenthic echinoderm were investigated at Dungonab Bay in the Red Sea coastal water of the Sudan. Four permanent line transects were chosen. Eight (30 × 2) square met...The abundance, distribution and diversity of epibenthic echinoderm were investigated at Dungonab Bay in the Red Sea coastal water of the Sudan. Four permanent line transects were chosen. Eight (30 × 2) square metre belt transects along each permanent line transect at 20 metre intervals were used to collect data. The data were subjected to univariate and multivariate analyses. Spatial variations of epibenthic echinoderm abundance were assessed with one-way analysis of variance. Hierarchical agglomerative clustering was used to identify and illustrate the similarities in echinoderm abundance between line transects and between belt transects. Indices of richness (d), diversity (H'), evenness (J') and dominance (C) were used to explain the diversity of epibenthic echinoderm species. The distribution pattern of each echinoderm species was determined in each permanent line transect. A total of 986 individuals were recorded within sixteen species of epibenthic echinoderms in the four line transects. Holothuriidae was the dominant family (5 species and 342 individuals). The most abundant echinoderms species was Pearsonothuria graeffei (77 individuals, about 7.81%). Abundances intra-transects and intra-families were insignificant (f = 1.67, p = 0.183, df = 3 and f = 3.24, p = 0.083, df = 9, respectively). The highest values of Shannon-Wiener diversity index (H'), Pielou evenness index (J'), Margalef species richness index (d), and Simpson Dominance index (C) were 2.738, 0.9875, 2.791 and 0.07159, respectively. The distribution patterns of all species in the study transects varied between clumped and uniform, with the exception of Asthenosoma varium of the Echinothuridae family, which had clumped distribution patterns in all transects. The study concluded that Dungonab Bay supports rich and diverse communities of epibenthic echinoderms.展开更多
Feeding behavior is regulated by a complex network of endogenous neuropeptides.In chordates,this role is suggested to be under the control of diverse factors including thyrotropin-releasing hormone(TRH).However,whethe...Feeding behavior is regulated by a complex network of endogenous neuropeptides.In chordates,this role is suggested to be under the control of diverse factors including thyrotropin-releasing hormone(TRH).However,whether this regulatory activity of TRH is functionally conserved in non-chordate metazoans,and to what extent this process is underpinned by interactions of TRH with other neuropeptides such as cholecystokinin(CCK,known as a satiety signal),remain unclear.This study investigated the TRH signaling system in the echinoderm Apostichopus japonicus.Bioinformatic analyses and ligand-binding assays identified a functional TRH receptor(AjTRHR)that activated signaling via the MAPK/ERK1/2pathways.Experimental administration of TRH significantly reduced feeding activity,while up-regulating CCK expression.RNA interference(RNAi)experiments confirmed that both CCK and TRH are essential components of satiety signaling,working synergistically to mediate feeding inhibition.Evolutionary analysis of TRHtype peptides revealed greater conservation of the short isoform of TRH compared to the long isoform,probably driven by strong selection acting on the functional redundancy.These findings provide compelling evidence of a TRH-mediated signaling system in non-chordate deuterostomes,expandingourunderstandingof neuropeptide-regulated feeding mechanisms in marine invertebrates.展开更多
文摘The abundance, distribution and diversity of epibenthic echinoderm were investigated at Dungonab Bay in the Red Sea coastal water of the Sudan. Four permanent line transects were chosen. Eight (30 × 2) square metre belt transects along each permanent line transect at 20 metre intervals were used to collect data. The data were subjected to univariate and multivariate analyses. Spatial variations of epibenthic echinoderm abundance were assessed with one-way analysis of variance. Hierarchical agglomerative clustering was used to identify and illustrate the similarities in echinoderm abundance between line transects and between belt transects. Indices of richness (d), diversity (H'), evenness (J') and dominance (C) were used to explain the diversity of epibenthic echinoderm species. The distribution pattern of each echinoderm species was determined in each permanent line transect. A total of 986 individuals were recorded within sixteen species of epibenthic echinoderms in the four line transects. Holothuriidae was the dominant family (5 species and 342 individuals). The most abundant echinoderms species was Pearsonothuria graeffei (77 individuals, about 7.81%). Abundances intra-transects and intra-families were insignificant (f = 1.67, p = 0.183, df = 3 and f = 3.24, p = 0.083, df = 9, respectively). The highest values of Shannon-Wiener diversity index (H'), Pielou evenness index (J'), Margalef species richness index (d), and Simpson Dominance index (C) were 2.738, 0.9875, 2.791 and 0.07159, respectively. The distribution patterns of all species in the study transects varied between clumped and uniform, with the exception of Asthenosoma varium of the Echinothuridae family, which had clumped distribution patterns in all transects. The study concluded that Dungonab Bay supports rich and diverse communities of epibenthic echinoderms.
基金supported by the National Natural Science Foundation of China (42276103)。
文摘Feeding behavior is regulated by a complex network of endogenous neuropeptides.In chordates,this role is suggested to be under the control of diverse factors including thyrotropin-releasing hormone(TRH).However,whether this regulatory activity of TRH is functionally conserved in non-chordate metazoans,and to what extent this process is underpinned by interactions of TRH with other neuropeptides such as cholecystokinin(CCK,known as a satiety signal),remain unclear.This study investigated the TRH signaling system in the echinoderm Apostichopus japonicus.Bioinformatic analyses and ligand-binding assays identified a functional TRH receptor(AjTRHR)that activated signaling via the MAPK/ERK1/2pathways.Experimental administration of TRH significantly reduced feeding activity,while up-regulating CCK expression.RNA interference(RNAi)experiments confirmed that both CCK and TRH are essential components of satiety signaling,working synergistically to mediate feeding inhibition.Evolutionary analysis of TRHtype peptides revealed greater conservation of the short isoform of TRH compared to the long isoform,probably driven by strong selection acting on the functional redundancy.These findings provide compelling evidence of a TRH-mediated signaling system in non-chordate deuterostomes,expandingourunderstandingof neuropeptide-regulated feeding mechanisms in marine invertebrates.
