Browsing by Author "Li, Zhi"
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- Domain-dependent evolution explains functional homology of protostome and deuterostome complement C3-like proteinsPublication . Peng, Maoxiao; Li, Zhi; Cardoso, João; Niu, Donghong; Liu, Xiaojun; Dong, Zhiguo; Li, Jiale; Power, DeborahComplement proteins emerged early in evolution but outside the vertebrate clade they are poorly characterized. An evolutionary model of C3 family members revealed that in contrast to vertebrates the evolutionary trajectory of C3-like genes in cnidarian, protostomes and invertebrate deuterostomes was highly divergent due to independent lineage and species-specific duplications. The deduced C3-like and vertebrate C3, C4 and C5 proteins had low sequence conservation, but extraordinarily high structural conservation and 2-chain and 3-chain protein isoforms repeatedly emerged. Functional characterization of three C3-like isoforms in a bivalve representative revealed that in common with vertebrates complement proteins they were cleaved into two subunits, b and a, and the latter regulated inflammation-related genes, chemotaxis and phagocytosis. Changes within the thioester bond cleavage sites and the a-subunit protein (ANATO domain) explained the functional differentiation of bivalve C3-like. The emergence of domain-related functions early during evolution explains the overlapping functions of bivalve C3-like and vertebrate C3, C4 and C5, despite low sequence conservation and indicates that evolutionary pressure acted to conserve protein domain organization rather than the primary sequence.
- Dopamine beta-hydroxylase and its role in regulating the growth and larval metamorphosis in Sinonovacula constrictaPublication . Li, Zhi; Niu, Donghong; Peng, Maoxiao; Xiong, Ya; Ji, Jie; Dong, Zhiguo; Li, JialeDopamine beta-hydroxylase (D beta H) plays a key role in the synthesis of catecholamines (CAs) in the neuroendocrine regulatory network. The D beta H gene was identified from the razor clam Sinonovacula constricta and referred to as ScD beta H. The ScD beta H gene is a copper type II ascorbate-dependent monooxygenase with a DOMON domain and two Cu2_monooxygen domains. ScD beta H transcript expression was abundant in liver and hemolymph. During early development, ScD beta H expression significantly increased at the umbo larval stage. Furthermore, the inhibitors and siRNA of D beta H were screened. After challenge with D beta H inhibitor, the larval metamorphosis and survival rates, and juvenile growth were obviously decreased. Under the siRNA stress, the larval metamorphosis and survival rates were also significantly decreased. Therefore, ScD beta H may play an important regulating role in larval metamorphosis and juvenile growth.
- Evolution and potential function in molluscs of neuropeptide and receptor homologues of the insect allatostatinsPublication . Li, Zhi; Cardoso, João; Peng, Maoxiao; Inácio, João P. S.; Power, DeborahThe allatostatins (ASTs), AST-A, AST-B and AST-C, have mainly been investigated in insects. They are a large group of small pleotropic alloregulatory neuropeptides that are unrelated in sequence and activate receptors of the rhodopsin G-protein coupled receptor family (GPCRs). The characteristics and functions of the homologue systems in the molluscs (Buccalin, MIP and AST-C-like), the second most diverse group of protostomes after the arthropods, and of high interest for evolutionary studies due to their less rearranged genomes remains to be explored. In the present study their evolution is deciphered in molluscs and putative functions assigned in bivalves through meta-analysis of transcriptomes and experiments. Homologues of the three arthropod AST-type peptide precursors were identified in molluscs and produce a larger number of mature peptides than in insects. The number of putative receptors were also distinct across mollusc species due to lineage and species-specific duplications. Our evolutionary analysis of the receptors identified for the first time in a mollusc, the cephalopod, GALR-like genes, which challenges the accepted paradigm that AST-AR/buccalin-Rs are the orthologues of vertebrate GALRs in protostomes. Tissue transcriptomes revealed the peptides, and their putative receptors have a widespread distribution in bivalves and in the bivalve Mytilus galloprovincialis, elements of the three peptide-receptor systems are highly abundant in the mantle an innate immune barrier tissue. Exposure of M. galloprovincialis to lipopolysaccharide or a marine pathogenic bacterium, Vibrio harveyi, provoked significant modifications in the expression of genes of the peptide precursor and receptors of the AST-C-like system in the mantle suggesting involvement in the immune response. Overall, our study reveals that homologues of the arthropod AST systems in molluscs are potentially more complex due to the greater number of putative mature peptides and receptor genes. In bivalves they have a broad and varying tissue distribution and abundance, and the elements of the AST-C-like family may have a putative function in the immune response.
- Inland alkaline brackish water aquaculture of juvenile razor clam: survival, growth, physiology and immune responsesPublication . Peng, Maoxiao; Li, Zhi; Liu, Xiaojun; Niu, Donghong; Li, JialeIn this study, we investigated rearing and breeding razor clam (Sinonovacula constricta) in inland alkaline brackish water. During 45 days of the experiment in candidate target inland area brackish water (TBW), survival, growth, enzyme activity and immune responses were analysed. The results showed that shell length and weight were significantly inhibited in the TBW group (p <0.001). Although the cumulative mortality was 81.479 ± 7.028 (p < 0.001) at 15 days, it increased slowly to 92.915 ± 2.271 (p < 0.001) at 45 days. The enzyme activities of Na+/K+-ATPase, aspartate aminotransferase and superoxide dismutase peaked at 15 days, and juvenile S. constricta (JSC) may engaged in partial anaerobic metabolism or damage to gill tissue, which may explain the high mortality rate at this time. Additionally, the phagocytic ability of haemocytes was inhibited (p < 0.001), but the metabolic activity was enhanced (p < 0.001). This implies that 15 days was the peak of TBW stress, and stress gradually decreased by days 30 and 45. TBW affected metabolism, osmotic regulation, and immune responses. There was an independent ionic interaction perhaps effect on JSC, primarily through Na+/K+ rate. Approximately 7 % of animals adapted successfully to TBW after 45 days. In summary, S. constricta has a great potential in further anti-TBW conditions selective breeding research.
- Neuropeptides regulate shell growth in the Mediterranean mussel (Mytilus galloprovincialis)Publication . Li, Zhi; Peng, Maoxiao; Félix, Rute; Cardoso, João; Power, Deborah MaryIn bivalves, which are molluscs enclosed in a biomineralized shell, a diversity of neuropeptide precursors has been described but their involvement in shell growth has been largely neglected. Here, using a symmetric marine bivalve, the Mediterranean mussel (Mytilus galloprovincialis), we uncover a role for the neuroendocrine system and neuropeptides in shell production. We demonstrate that the mantle is rich in neuropeptide precursors and that a complex network of neuropeptide-secreting fibres innervates the mantle edge a region highly involved in shell growth. We show that shell damage and shell repair significantly modify neuropeptide gene expression in the mantle edge and the nervous ganglia (cerebropleural ganglia, CPG). When the CPG nerve commissure was severed, shell production was impaired after shell damage, and modified neuropeptide gene expression, the spatial organization of nerve fibres in the ganglia and mantle and biomineralization enzyme activity in the mantle edge. Injection of CALCIa and CALCIIa peptides rescued the impaired shell repair phenotype providing further support for their role in biomineralization. We propose that the regulatory mechanisms identified are likely to be conserved across bivalves and other shelled molluscs since they all share a similar nervous system, a common mantle biomineralization toolbox, and shell structure.
- Regulatory mechanisms of the bivalve mantle and their association with shell biomineralizationPublication . Li, Zhi; Power, Deborah M.; Cardoso, João Carlos dos ReisThe significance of bivalves lies both in their economic importance to the aquaculture and food industry and their ecological roles in marine environments. Biomineralized shells are a hallmark of bivalves, enclosing their soft bodies and being crucial for their survival. Although various neuropeptide precursors have been described, their role in biomineralization has not been emphasized. The primary objective of this paper is to explore the role of neuropeptides in the nervous system and mantle, and to investigate how the nervous system regulates mantle function. It aims to study how the nervous system regulates the biomineralization process and elucidate the complex mechanisms controlling mantle physiology and shell formation. The experimental methods used in this study include omics analysis. Additionally, the symmetrical marine bivalve, Mediterranean mussel (Mytilus galloprovincialis), was selected as the experimental subject, and verification experiments were conducted at the immunohistochemical, molecular, and functional levels. The results of this study suggest that: 1) Neuropeptide gene expression at the mantle edge and in the cerebropleural ganglia (CPG) regulates shell regrowth. 2) Severing the CPG commissure inhibits shell regrowth and alters neuropeptide gene expression as well as the spatial organization of nerve fibers in the ganglia and mantle. 3) In the symmetrical bivalve M. galloprovincialis, gene expression in the left and right sides of the mantle is not completely symmetrical. 4) The CPG regulates the expression of genes related to biomineralization, with lncRNAs appearing to play an important role in the biomineralization process. This paper provides strong evidence that neuropeptides and the nervous system influence mantle function and shell growth in bivalves. These findings contribute to our understanding of the role of the neuroendocrine system and neuropeptides in the mantle biomineralization toolbox of bivalves.
- Revisiting the evolution of family B1 GPCRs and ligands: insights from molluscaPublication . Cardoso, João; Mc Shane, Jennifer; Li, Zhi; Peng, Maoxiao; Power, Deborah MaryFamily B1 G protein-coupled receptors (GPCRs) are one of the most well studied neuropeptide receptor families since they play a central role in many biological processes including endocrine, gastrointestinal, cardiovascular and reproduction in animals. The genes for these receptors emerged from a common ancestral gene in bilaterian genomes and evolved via gene/genome duplications and deletions in vertebrate and invertebrate genomes. Their existence and function have mostly been characterized in vertebrates and few studies exist in invertebrate species. Recently, an increased interest in molluscs, means a series of genomes have become available, and since they are less modified than insect and nematode genomes, they are ideal to explore the origin and evolution of neuropeptide gene families. This review provides an overview of Family B1 GPCRs and their peptide ligands and incorporates new data obtained from Mollusca genomes and taking a comparative approach challenges existing models on their origin and evolution.
- RNAi-mediated knock-down of the dopamine beta-hydroxylase gene changes growth of razor clamsPublication . Li, Zhi; Peng, Maoxiao; Power, Deborah; Niu, Donghong; Dong, Zhiguo; Li, JialeDopamine beta-hydroxylase (D beta H) plays an essential role in the synthesis of catecholamines (CA) in neuroen-docrine networks. In the razor clam, Sinonovacula constricta a novel gene for D beta H (ScD beta H-alpha) was identified that belongs to the copper type II ascorbate-dependent monooxygenase family. Expression analysis revealed ScD beta H-alpha gene transcripts were abundant in the liver and expressed throughout development. Knock-down of ScD beta H-alpha in adult clams using siRNA caused a reduction in the growth rate compared to control clams. Reduced growth was associated with strong down-regulation of gene transcripts for the growth-related factors, platelet derived growth factors A (PDGF-A) (P < 0.001) 24 h after ScD beta H-alpha knock-down, vascular endothelial growth factor (VEGF1) (P < 0.001) and platelet derived growth factor B (PDGF-B-2)(P < 0.001) 24 h and 48 h after ScD beta H-alpha knock-down and transforming growth factor beta (TGF-beta 1) (P < 0.001) 48 h and 72 h after ScD beta H-alpha knock-down. Taken together the results suggest that the novel ScD beta H-alpha gene through its role in CA synthesis is involved in growth regulation in the razor clam and possibly other bivalves.