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Featured researches published by Maoxian He.


Chinese Journal of Oceanology and Limnology | 2012

Effects of ocean acidification on the metabolic rates of three species of bivalve from southern coast of China

Wenguang Liu (刘文广); Maoxian He

Oceanic uptake of anthropogenic carbon dioxide results in a decrease in seawater pH, a process known as “ocean acidification”. The pearl oyster Pinctada fucata, the noble scallop Chlamys nobilis, and the green-lipped mussel Perna viridis are species of economic and ecological importance along the southern coast of China. We evaluated the effects of seawater acidification on clearance, respiration, and excretion rates in these three species. The ammals were reared in seawater at pH 8.1 (control), 7.7, or 7.4. The clearance rate was highest at pH 7.7 for P. fucata and at pH 8.1 for C. nobilis and P. viridis. The pH had little effect on the respiration rate of P. fucata and P. viridis. In contrast, the respiration rate was significantly lower at pH 7.4 in C. nobilis. The excretion rate was significantly lower at pH 7.4 than pH 8.1 for all species. The results indicate that the reduction in seawater pH likely affected the metabolic process (food intake, oxygen consumption, and ammonia excretion) of these bivalves. Different species respond differently to seawater acidification. Further studies are needed to demonstrate the exact mechamsms for this effect and evaluate adaptability of these bivalves to future acidified oceans.


PLOS ONE | 2012

Seawater Acidification and Elevated Temperature Affect Gene Expression Patterns of the Pearl Oyster Pinctada fucata

Wenguang Liu; Xiande Huang; Jianshi Lin; Maoxian He

Oceanic uptake of anthropogenic carbon dioxide results in decrease in seawater pH and increase in temperature. In this study, we demonstrated the synergistic effects of elevated seawater temperature and declined seawater pH on gene expression patterns of aspein, calmodulin, nacrein, she-7-F10 and hsp70 in the pearl oyster Pinctada fucata. Under ‘business-as-usual’ scenarios, four treatments were examined: (1) ambient pH (8.10) and ambient temperature (27°C) (control condition), (2) ambient pH and elevated temperature (+3°C), (3) declined pH (7.70) and ambient temperature, (4) declined pH and elevated temperature. The results showed that under warming and acidic seawater conditions, expression of aspein and calmodulin showed no significant differences among different time point in condition 8.10 T. But the levels of aspein and calmodulin in conditions 8.10 T+3, 7.70 T and 7.70 T+3, and levels of nacrein, she-7-F10 in all the four treatments changed significantly. Low pH and pH×temperature interaction influenced the expression of aspein and calmodulin significantly after hours 48 and 96. Significant effects of low pH and pH×temperature interaction on the expression of nacrein were observed at hour 96. The expression level of she-7-F10 was affected significantly by pH after hours 48 and 96. The expression of hsp70 was significantly affected by temperature, pH, temperature×pH interaction at hour 6, and by temperature×pH interaction at hour 24. This study suggested that declined pH and pH×temperature interaction induced down regulation of calcification related genes, and the interaction between declined seawater pH and elevated temperature caused up regulation of hsp70 in P. facata. These results demonstrate that the declined seawater pH and elevated temperature will impact the physiological process, and potentially the adaptability of P. fucata to future warming and acidified ocean.


Fish & Shellfish Immunology | 2013

Molecular characterization of interferon regulatory factor 2 (IRF-2) homolog in pearl oyster Pinctada fucata.

Xiande Huang; Wenguang Liu; Qi Wang; Mi Zhao; Shan-Zeng Wu; Yunyan Guan; Yu Shi; Maoxian He

Interferon regulatory factors (IRFs) control many facets of the innate and adaptive immune responses, regulate the development of the immune system itself and involve in reproduction and morphogenesis. In the present study, the IRF-2 homology gene, PfIRF-2 from pearl oyster Pinctada fucata was cloned and its genomic structure and promoter were analyzed. PfIRF-2 encodes a putative protein of 350 amino acids, and contains a highly conserved N-terminal DNA-binding domain and a variable C-terminal regulatory domain. Comparison and phylogenetic analysis revealed that PfIRF-2 shared a relatively higher identity with other mollusk but relatively lower identity with vertebrate IRF-2, and was clustered with IRF-1 subfamily composed of IRF-2 and IRF-1. Furthermore, gene expression analysis revealed that PfIRF-2 involved in the immune response to LPS and poly(I:C) stimulation. Immunofluorescence assay showed that the expressed PfIRF-2 was translocated into the nucleus and dual-luciferase reporter assays indicated that PfIRF-2 could involved and activate interferon signaling or NF-κB signal pathway in HEK293 cells. The study of PfIRF-2 may help better understand the innate immune in mollusk.


Fish & Shellfish Immunology | 2012

Molecular cloning, characterization and expression analysis of tumor necrosis factor receptor-associated factor 3 (TRAF3) from pearl oyster Pinctada fucata.

Xiande Huang; Wenguang Liu; Yunyan Guan; Yu Shi; Qi Wang; Mi Zhao; Shan-Zeng Wu; Maoxian He

TRAF3 is a highly versatile regulator that negatively regulates JNK and alternative nuclear factor-κB signalling, but positively controls type I interferon production. To investigate TRAF3 function in innate immune responses among invertebrate especially mollusk, we characterized TRAF3 (PfTRAF3) from pearl oyster Pinctada fucata, one of the most important bivalve mollusks for seawater pearl production. PfTRAF3 cDNA is 2261 bp with an open reading frame of 1623 bp encoding a putative protein of 541 amino acids. The deduced PfTRAF3 contains a RING finger domain, two TRAF domains with zinc finger domains and a conserved C-terminal meprin and TRAF homology (MATH) domain. Comparison and phylogenetic analysis revealed that PfTRAF3 from mollusk shared a higher identity with Ciona intestinalis TRAF3 from urochordata, Branchiostoma belcheri TRAF3 from cephalochordate, and even TRAF3 from vertebrate than with insect homologues. Furthermore, gene expression analyses suggested that PfTRAF3 was involved in the immune response to Vibrio alginolyticus.


PLOS ONE | 2014

Genetic Mapping and QTL Analysis of Growth-Related Traits in Pinctada fucata Using Restriction-Site Associated DNA Sequencing

Yaoguo Li; Maoxian He

The pearl oyster, Pinctada fucata (P. fucata), is one of the marine bivalves that is predominantly cultured for pearl production. To obtain more genetic information for breeding purposes, we constructed a high-density linkage map of P. fucata and identified quantitative trait loci (QTL) for growth-related traits. One F1 family, which included the two parents, 48 largest progeny and 50 smallest progeny, was sampled to construct a linkage map using restriction site-associated DNA sequencing (RAD-Seq). With low coverage data, 1956.53 million clean reads and 86,342 candidate RAD loci were generated. A total of 1373 segregating SNPs were used to construct a sex-average linkage map. This spanned 1091.81 centimorgans (cM), with 14 linkage groups and an average marker interval of 1.41 cM. The genetic linkage map coverage, Coa, was 97.24%. Thirty-nine QTL-peak loci, for seven growth-related traits, were identified using the single-marker analysis, nonparametric mapping Kruskal-Wallis (KW) test. Parameters included three for shell height, six for shell length, five for shell width, four for hinge length, 11 for total weight, eight for soft tissue weight and two for shell weight. The QTL peak loci for shell height, shell length and shell weight were all located in linkage group 6. The genotype frequencies of most QTL peak loci showed significant differences between the large subpopulation and the small subpopulation (P<0.05). These results highlight the effectiveness of RAD-Seq as a tool for generation of QTL-targeted and genome-wide marker data in the non-model animal, P. fucata, and its possible utility in marker-assisted selection (MAS).


PLOS ONE | 2014

A Homeodomain Transcription Factor Gene, PfMSX, Activates Expression of Pif Gene in the Pearl Oyster Pinctada fucata

Mi Zhao; Maoxian He; Xiande Huang; Qi Wang

We reported pearl oyster Pinctada fucata cDNA and genomic characterization of a new homeobox-containing protein, PfMSX. The PfMSX gene encodes a transcription factor that was localized to the nucleus. Analyses of PfMSX mRNA in tissues and developmental stages showed high expressions in mantle or D-shaped larvae. In electrophoretic mobility shift assays (EMSAs) PfMSX binded to MSX consensus binding sites in the 5′ flanking region of the Pif promoter. In co-transfection experiment PfMSX transactivated reporter constructs containing Pif promoter sequences, and mutation of the MSX-binding sites attenuated transactivation. A knockdown experiment using PfMSX dsRNA showed decreased Pif mRNA and unregular crystallization of the nacreous layer using scanning electron microscopy. Our results suggested that PfMSX was a conserved homeodomain transcription factor gene, which can activate Pif gene expression through MSX binding site, and was then involved in the mineralization process in pearl oyster Pinctada fucata. Our data provided important clues about mechanisms regulating biomineralization in pearl oyster.


General and Comparative Endocrinology | 2014

Molecular characterization and analysis of a putative 5-HT receptor involved in reproduction process of the pearl oyster Pinctada fucata

Qi Wang; Maoxian He

5-HT (5-hydroxytryptamine; serotonin) has been linked to a variety of biological roles including gonad maturation and sequential spawning in bivalve molluscs. To gain a better understanding of the effects of 5-HT on developmental regulation in the pearl oyster Pinctada fucata, the isolation, cloning, and expression of the 5-HT receptor was investigated in this study. A full-length cDNA (2541 bp) encoding a putative 5-HT receptor (5-HTpf) of 471 amino acids was isolated from the ovary of the pearl oyster. It shared 71% and 51% homology, respectively, with the Crassostrea gigas 5-HT receptor and the Aplysia californica 5-HT1ap. The 5-HTpf sequence possessed the typical characteristics of seven transmembrane domains and a long third inner loop. Phylogenetic analysis also indicated that 5-HTpf was classified into the 5-HT1 subtype together with other invertebrate 5-HT1 receptors. Quantitative RT-PCR showed that 5-HTpf is widely expressed in all tissues tested, is involved in the gametogenesis cycle, embryonic and larval development stages, and expression is induced by E2 in ovarian tissues. These results suggest that 5-HTpf is involved in the reproductive process, specifically in the induction of oocyte maturation and spawning of P. fucata.


Fish & Shellfish Immunology | 2015

Cloning and gene expression of signal transducers and activators of transcription (STAT) homologue provide new insights into the immune response and nucleus graft of the pearl oyster Pinctada fucata.

Xiande Huang; Guo-jian Wei; Maoxian He

The signal transducers and activators of the transcription (STAT) family play an important role in regulatory and cellular functions by regulating the expression of a variety of genes, including cytokines and growth factors. In the present study, a Pinctada fucata STAT protein, termed PfSTAT, was described. The deduced amino acid sequence of PfSTAT contains the conserved STAT_bind domain and the SH2 domain, and the additional Bin/Amphiphysin/Rvs (BAR) domain, but does not have STAT_alpha and STAT_int domains. Multiple sequence alignments revealed that PfSTAT showed relatively low identity with vertebrate and other invertebrate STATs, and phylogenetic analysis indicated that the evolution of STAT may have been more complex and ancient. Gene expression analysis revealed that PfSTAT is involved in the immune response to polyinosinic-polycytidylic acid (poly I:C) stimulation and in the nucleus insertion operation. This study contributes to a better understanding of PfSTAT in protecting the pearl oyster from disease or injury caused by grafting.


Fish & Shellfish Immunology | 2015

Nuclear factor of activated T cells (NFAT) in pearl oyster Pinctada fucata: molecular cloning and functional characterization.

Xiande Huang; Guo-jian Wei; Hua Zhang; Maoxian He

Nuclear factor of activated T cells (NFAT) plays an important role in nonimmune cells and also in T cells and many other cells of the immune system, by regulating the expression of a variety of genes involved in the immune response, organ development, developmental apoptosis and angiogenesis. In the present study, the NFAT homology gene, PfNFAT, from the pearl oyster Pinctada fucata was cloned and its genomic structure and promoter were analyzed. PfNFAT encodes a putative protein of 1226 amino acids, and contains a highly conserved Rel homology region (RHR) with DNA-binding specificity, and a regulatory domain (NFAT homology region, NHR) containing a potent transactivation domain (TAD). The PfNFAT gene consists of 12 exons and 11 introns, and its promoter contains potential binding sites for transcription factors such as NF-κB (Nuclear factor κB), STATx (signal transducer and activator of transcription), AP-1 (activator protein-1) and Sox-5/9 (SRY type HMG box-5/9), MyoD (Myogenic Differentiation Antigen) and IRF (Interferon regulatory factor). Comparison and phylogenetic analysis revealed that PfNFAT shows high identity with other invertebrate NFAT, and clusters with the NFAT5 subgroup. Furthermore, gene expression analysis revealed that PfNFAT is involved in the immune response to lipopolysaccharide (LPS) and Polyinosinic-polycytidylic acid (poly I:C) stimulation and in the nucleus inserting operation. The study of PfNFAT may increase understanding of molluscan innate immunity.


Journal of Genetics | 2015

Identification of sixteen single-nucleotide polymorphism markers in the pearl oyster, Pinctada fucata, for population genetic structure analysis

Xiande Huang; Shan-Zeng Wu; Yunyan Guan; Yaoguo Li; Maoxian He

The pearl oyster, Pinctada fucata, a marine bivalve belonging to the family Pteriidae, is the primary species cultured for marine pearls in China and Japan (Zhang 2002). To increase the yield, successful techniques for artificial breeding have been established in China (Zhang 2002). However, with increasing acreage for artificial farming, several issues such as declining genetic diversity in culture are being taken into consideration in the modern pearl oyster farming industry. Further study on these topics would require the available genetic tools such as molecular markers (Liu and Cordes 2004). Single-nucleotide polymorphisms (SNPs) are nucleotide variations in the DNA sequence of individuals. As the most abundant molecular markers in the genome, they are sequence-tagged markers with codominant inheritance, and thus are ideal for population genetic studies (Morin et al. 2004). Therefore, in recent years, SNP have been characterized and applied in many aquaculture species such as Salmo salar (Hayes et al. 2007), Crassostrea virginica (Zhang and Guo 2010) and Chlamys farreri (Li et al. 2013). However, to our knowledge, although the draft genome of P. fucata has been established which could provide a platform for the identification of selection markers (Takeuchi et al. 2012), there are no SNP loci which have been identified for the pearl oyster, P. fucata. At present, there are many SNP genotyping systems (Kim and Misra 2007). For our research focussing on developing a limited number of SNP markers for

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Xiande Huang

Chinese Academy of Sciences

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Yu Shi

Chinese Academy of Sciences

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Wenguang Liu

Chinese Academy of Sciences

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Yunyan Guan

Chinese Academy of Sciences

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Hua Zhang

Chinese Academy of Sciences

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Mi Zhao

Chinese Academy of Sciences

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Qi Wang

Chinese Academy of Sciences

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Shan-Zeng Wu

Chinese Academy of Sciences

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Tao Yuan

Chinese Academy of Sciences

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Yaoguo Li

Chinese Academy of Sciences

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