The Experts below are selected from a list of 201 Experts worldwide ranked by ideXlab platform
Siuming Chan - One of the best experts on this subject based on the ideXlab platform.
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Comparative transcriptomics reveals Eyestalk ablation induced responses of the neuroendocrine-immune system in the Pacific white shrimp Litopenaeus vannamei.
Fish & shellfish immunology, 2020Co-Authors: Jiahui Liu, Tingting Zhou, Chenggui Wang, Wei Wang, Siuming ChanAbstract:Abstract In decapod crustaceans, Eyestalk ablation is widely used to expedite ovarian maturation and spawning because of the removal of a gonad inhibiting hormone produced by the X-organ sinus gland. However, Eyestalk ablation also results in negative impacts on the immunocompetence of the Eyestalk-ablated females. In the current study, we investigated the impact of Eyestalk ablation on the transcriptomic responses of three major nervous organs of shrimp, including the Eyestalk ganglion, brain and thoracic ganglion, using the Illumina Hiseq™ 4000 platform. A total of 48,249 unigenes with an average length of 1253 bp and a N50 value of 2482 bp were obtained. Following Eyestalk ablation treatment, a total of 2,983, 6325 and 6575 unigenes were detected as differentially expressed (log2Ratio >1 and FDR
Jie Kong - One of the best experts on this subject based on the ideXlab platform.
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Comparative transcriptomic characterization of the Eyestalk in Pacific white shrimp (Litopenaeus vannamei) during ovarian maturation.
General and comparative endocrinology, 2019Co-Authors: Zhongkai Wang, Sheng Luan, Xianhong Meng, Baoxiang Cao, Kun Luo, Jie KongAbstract:In crustaceans, some of fundamental regulatory processes related to a range of physiological functions, including ovarian maturation, molting, glucose homeostasis, osmoregulation, etc., occur in the organs of the Eyestalk. Additionally, reproduction is regulated by neuropeptide hormones and other proteins released from secretory sites (X-organ/sinus gland, XO/SG) within the Eyestalk. As unilateral Eyestalk ablation was the most common method used to artificially induce ovarian maturation for farmed Litopenaeus vannamei, to better understand the reproductive regulation mechanism in L. vannamei, we have investigated the transcriptomes of the Eyestalk during five ovary developmental stages with or without Eyestalk ablation by high-throughput Illumina sequencing technology. The raw reads were assembled and clustered into 127,031 unigenes. Meanwhile, the differentially expressed genes (DEGs) between ovarian development stages were identified. We examined, through DEG enrichment analysis, Eyestalk gene expression patterns for Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways, comparing natural to artificially induced ovarian maturation. We also identified a variety of transcripts that appear to be differentially expressed throughout ovarian maturation. These include transcripts that encode G-protein coupled receptors (GPCRs) and neuropeptides, such as the crustacean hyperglycemic hormone (CHH), molt-inhibiting hormone (MIH), and crustacean female sex hormone (CFSH). Furthermore, numerous exoskeleton formation-related genes were found to be down-regulated during ovarian maturation, including cuticle-like proteins, eclosion hormone (EH), and gastrolith-like proteins, of which the latter are the first reported in L. vannamei. Our work is the first reproduction-related investigation of L. vannamei focusing on the Eyestalk at the whole transcriptome level. These findings provide novel insight into the function of the Eyestalk in reproduction regulation.
Chunhua Ren - One of the best experts on this subject based on the ideXlab platform.
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pacific white shrimp litopenaeus vannamei vitellogenesis inhibiting hormone vih is predominantly expressed in the brain and negatively regulates hepatopancreatic vitellogenin vtg gene expression
Biology of Reproduction, 2014Co-Authors: Ting Chen, Lvping Zhang, Naikei Wong, Ming Zhong, Chunhua RenAbstract:Ovarian maturation in crustaceans is temporally orchestrated by two processes: oogenesis and vitellogenesis. The peptide hormone vitellogenesis-inhibiting hormone (VIH), by far the most potent negative regulator of crustacean reproduction known, critically modulates crustacean ovarian maturation by suppressing vitellogenin (VTG) synthesis. In this study, cDNA encoding VIH was cloned from the Eyestalk of Pacific white shrimp, Litopenaeus vannamei, a highly significant commercial culture species. Phylogenetic analysis suggests that L. vannamei VIH (lvVIH) can be classified as a member of the type II crustacean hyperglycemic hormone family. Northern blot and RT-PCR results reveal that both the brain and Eyestalk were the major sources for lvVIH mRNA expression. In in vitro experiments on primary culture of shrimp hepatopancreatic cells, it was confirmed that some endogenous inhibitory factors existed in L. vannamei hemolymph, brain, and Eyestalk that suppressed hepatopancreatic VTG gene expression. Purified recombinant lvVIH protein was effective in inhibiting VTG mRNA expression in both in vitro primary hepatopancreatic cell culture and in vivo injection experiments. Injection of recombinant VIH could also reverse ovarian growth induced by Eyestalk ablation. Furthermore, unilateral Eyestalk ablation reduced the mRNA level of lvVIH in the brain but not in the remaining contralateral Eyestalk. Our study, as a whole, provides new insights on VIH regulation of shrimp reproduction: 1) the brain and Eyestalk are both important sites of VIH expression and therefore possible coregulators of hepatopancreatic VTG mRNA expression and 2) Eyestalk ablation could increase hepatopancreatic VTG expression by transcriptionally abolishing Eyestalk-derived VIH and diminishing brain-derived VIH.
Koji Nakanishi - One of the best experts on this subject based on the ideXlab platform.
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Physiological role of 3-hydroxykynurenine and xanthurenic acid upon crustacean molting.
Advances in experimental medicine and biology, 1991Co-Authors: Yoko Naya, Mayumi Ohnishi, M. Ikeda, W. Miki, Koji NakanishiAbstract:Studies with crabs (Charybdis japonica) and crayfish (Procambarus clarkii) revealed that the tryptophan metabolites, 3-hydroxy-L-kynurenine (3-OH-K) and xanthurenic acid (XA), common secretory products of the X-organ-sinus gland complex of Eyestalks from several decapods, regulated the molting of crustaceans in species-nonspecific fashion. Injection of 3-OH-K to the Eyestalk-ablated crayfish delayed the onset of the first molt and lengthened the interval between the first and second molts. These lines of evidence were in accord with previous accounts of the so-called "molt inhibiting hormone" (MIH) effect. Removal of Eyestalks caused a change in the conversion capacity of exogenous 3-OH-K to XA in the hemolymph. The peak in transformation capacity was followed by a peak in the titer of 20-hydroxyecdysone or molting hormone. Moreover, the seasonal profiles of the XA and ecdysone titers in Charybdis japonica exhibited a staggered relationship in the tissues tested. The ratio of XA to 3-OH-K, which is expected to indicate the apparent 3-OH-Kase activity, fluctuated seasonally and locally. When the Y-organ with the adhering tissues (Y-organ complex or YOC) was incubated during the period of high XA titer, the YOC produced 100 times more ecdysone than before incubation. It is suggested that ecdysteroidogenesis in situ was suppressed during this period by XA, but incubation of the YOC lead to a dramatic acceleration in ecdysone synthesis by overriding this inhibitory effect. XA profoundly repressed ecdysteroidogenesis in the YOC culture. Thus, XA is the ecdysone biosynthesis inhibitor (EBI) and 3-OH-K the precursor in crustaceans. An interfering effect of XA to a biocatalyst cytochrome P-450 system was postulated for the inhibition mechanism of ecdysteroidogenesis.
Enrique M. Rodríguez - One of the best experts on this subject based on the ideXlab platform.
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Interference of an atrazine commercial formulation with the endocrine control of ovarian growth exerted by the Eyestalks.
Environmental science and pollution research international, 2019Co-Authors: Gabriela R. Silveyra, Ivana S. Canosa, Marina Zanitti, Enrique M. Rodríguez, Daniel A. MedesaniAbstract:Atrazine is currently one of the most used herbicides worldwide. We tested the possible effect of the widely used herbicide atrazine on the endocrine control of ovarian growth exerted by the neurohormones secreted at the Eyestalk of the estuarine crab Neohelice granulata. For this, both in vivo and in vitro assays were carried out. The in vivo assay comprised the exposure for 1 month to 3 mg/L of a commercial formulation containing 90% of atrazine as active ingredient (Gesaprim 90 WDG®, Syngenta) on three categories of females: intact, ablated of one Eyestalk, and ablated of both Eyestalks. At the end of the assay, only the intact females showed a significant (p < 0.05) decrease in both content of vitellogenic ovarian proteins and proportion of vitellogenic oocytes, compared to a concurrent control. The results of the in vitro incubation of ovarian pieces with the eventual addition to the incubation medium of Eyestalk tissue and/or atrazine at 3 mg/L showed a significant (p < 0.05) decrease in the proportion of vitellogenic oocytes only when atrazine and Eyestalk tissue were added. Taken together, these results strongly suggest that the assayed atrazine formulation may act as an endocrine disruptor at the Eyestalk level, by altering the normal secretion of some Eyestalk hormone, therefore inhibiting ovarian growth.
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inhibition of ovarian growth by cadmium in the fiddler crab uca pugilator decapoda ocypodidae
Ecotoxicology and Environmental Safety, 2000Co-Authors: Enrique M. Rodríguez, Laura Lopez S Greco, Milton FingermanAbstract:The effect of cadmium chloride (1 mg/L) on oocyte growth of the fiddler crab, Uca pugilator, was studied during the slow vitellogenesis phase of ovarian maturation of this carb. In vivo experiments were done with both intact and Eyestalkless crabs. The intact cadmium-exposed crabs exhibited a significantly lower oocyte diameter than the controls at the end of the 2-week exposure period, but no significant differences were detected among the Eyestalkless crabs, suggesting that the effect of cadmium could be on the sinus gland in the Eyestalks, increasing secretion of the gonad-inhibiting hormone (GIH). To test this hypothesis, in vitro experiments were done, incubating pieces of ovary with and without Eyestalk tissue, in the presence of thoracic ganglion, needed for oocyte growing due to the secretion of the gonad-stimulating hormone (GSH). Only when Eyestalk tissue was present in the incubation media was oocyte growth inhibited by cadmium compared to the controls. These results strongly suggest that cadmium acts at least in part to increase the secretion of GIH from the sinus gland. GIH could then in turn act by (a) inhibiting secretion of GSH by the thoracic ganglion, (b) directly inhibit the oocytes, or (c) both (a) and (b).
