Project description:Temperature profoundly influences the physiology, survival, and distribution of marine ectotherms, including mollusks. Transient receptor potential (TRP) channels are conserved thermosensory proteins in metazoans, yet their evolutionary diversification and functional roles in gastropod mollusks remain unclear. In this study, we present a comprehensive phylogenetic classification and expression analysis of TRP-like channel genes in Pacific abalone (Haliotis discus hannai). Through the extensive mining of genome and transcriptome datasets, we identified 49 TRP-like genes and categorized them into nine families from two major groups: Group 1 (TRPA, TRPC, TRPM, TRPN, TRPS, TRPV, and TRPVL) and Group 2 (TRPP and TRPML), along with two unclassified TRP-like genes. Phylogenetic analysis incorporating sequences from lophotrochozoans, choanoflagellates, fungi, and green algae outlined a lineage-specific TRP-like gene expansion in mollusks. Spatial expression profiling revealed distinct tissue-specific patterns: TRPC-, TRPM-, and TRPP-like genes were enriched in sensory organs (i.e., the eyes and tentacles), whereas TRPM- and TRPV-like genes were expressed predominantly in respiratory and metabolic tissues (i.e., the gills and hepatopancreas). Under acute thermal stress, RNA sequencing and real-time quantitative PCR identified several thermoresponsive TRP paralogs, including TRPA1- and TRPV-like genes, exhibiting distinct transcriptional regulation. These results elucidate the evolutionary complexity and functional diversification of TRP channels in marine gastropods, and highlight the potential role of these molecules in thermal sensing and adaptation. This study provides a molecular framework for understanding TRP-mediated environmental responses in mollusks, contributing to broader insights into marine invertebrate resilience under climate change.
Project description:The circadian rhythm is the most general and important rhythm in biological organisms. In this study, continuous 24 h video recordings showed that the cumulative movement distance and duration of the abalone, Haliotis discus hannai reached their maximum values between 20:00–00:00, but both were significantly lower between 08:00–12:00 than at any other time of day or night (P < 0.05). To investigate the causes of these diel differences in abalone movement behavior, their cerebral ganglia were harvested at 00:00 (group D) and 12:00 (group L) to screen for differentially expressed proteins using tandem mass tagging (TMT) quantitative proteomics. Seventy-five significantly different proteins were identified in group D vs. group L. Acetylcholinesterase (AChE) was found three times, and its expression levels differed significantly between day and night (P < 0.05). A cosine rhythm analysis found that the concentration of acetylcholine (Ach) and the expression levels of AchE tended to be low during the day and high at night, and high during the day and low at night, respectively.
Project description:Lactobacillus plantarum (LPsca12) enhances growth phenotype and muscle nutrition in abalone (Haliotis discus hannai) by modulating (PRJCA041928)
Project description:Abalone amyotrophia is a viral disease that causes mass mortality of juvenile Haliotis discus and H. madaka. Although the cause of this disease has yet to be identified, we had previously postulated a novel virus with partial genome sequence similarity to that of African swine fever virus is the causative agent and proposed abalone asfa-like virus (AbALV) as a provisional name. In this study, three species of juvenile abalone (H. gigantea, H. discus discus, and H. diversicolor) and four species of adult abalone (the above three species plus H. discus hannai) were experimentally infected, and their susceptibility to AbALV was investigated by recording mortality, quantitatively determining viral load by PCR, and conducting immunohistological studies. In the infection test using 7-month-old animals, H. gigantea, which was previously reported to be insusceptible to the disease, showed multiplication of the virus to the same extent as in H. discus discus, resulting in mass mortality. H. discus discus at 7 months old showed abnormal cell masses, notches in the edge of the shell and brown pigmentation inside of the shell, which are histopathological and external features of this disease, while H. gigantea did not show any of these characteristics despite suffering high mortality. Adult abalones had low mortality and viral replication in all species; however, all three species, except H. diversicolor, became carriers of the virus. In immunohistological observations, cells positive for viral antigens were detected predominantly in the gills of juvenile H. discus discus and H. gigantea, and mass mortality was observed in these species. In H. diversicolor, neither juvenile nor adult mortality from infection occurred, and the AbALV genome was not increased by experimental infection through cohabitation or injection. Our results suggest that H. gigantea, H. discus discus and H. discus hannai are susceptible to AbALV, while H. diversicolor is not. These results confirmed that AbALV is the etiological agent of abalone amyotrophia.
Project description:The invertebrate LFRFamide (LFRFa) and short neuropeptide F (sNPF), consisting of 6 to 10 amino acids, are orthologs for bilaterian NPF/Y, which consist of 36 to 40 amino acids. Recently, a molluscan G protein-coupled receptor (GPCR) for NPF was characterized in Pacific abalone (Haliotis discus hannai). To address the functional evolutionary route of the invertebrate LFRFa and NPF signaling system, in this study, we identified cDNAs encoding LFRFa precursors and the sNPF receptor (Hdh-sNPFR) in Pacific abalone. Four LFRFa mature peptides with 6 or 7 amino acids were predicted: GSLFRFa, GGLFRFa, GTLFRFa, and GSTLFRFa. Hdh-sNPFR was identified as a classical rhodopsin-like GPCR and classified into a molluscan sNPFR group. In HEK293 cells, Hdh-sNPFR was mainly localized in the cell membranes and internalized in the cytoplasm following treatment with LFRFa peptides. Reporter assays demonstrated that LFRFa peptides inhibit forskolin-stimulated cAMP accumulation in Hdh-sNPFR-expressing HEK293 cells. LFRFa precursor and Hdh-sNPFR transcripts were more strongly expressed in the cerebral and pleural-pedal ganglia of Pacific abalone than in the peripheral tissues such as the ovary, gills, intestine, and hepatopancreas. The levels of LFRFa transcripts in the ovary, intestine, and hepatopancreas were significantly higher in mature female abalone than in immature females. Injection of LFRFa induced the egg release and spawning behavior of mature abalone, but suppressed food intake. These results suggest that LFRFa peptides are endogenous ligands for Hdh-sNPFR involved in food intake and reproduction through a Gαi-protein dependent signaling pathway.