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ABSTRACT:   Taurine is the primary osmolyte in marine molluscs, whose cellular osmo-conforming process is vital for environmental adaptation because of a lack of osmotic homeostasis. Here, cDNA cloning and expression, and functional analyses of taurine transporter (TAUT) from the giant Pacific oyster are reported on. The deduced amino-acid sequence of oyster TAUT (oyTAUT) showed 47–51% identity to those of vertebrate TAUT, whereas identity among the vertebrates is 78–95%. Functional analysis of oyTAUT expressed in Xenopus oocytes revealed that oyTAUT has a lower affinity and specificity for taurine and a requirement for higher NaCl concentration, compared with vertebrate TAUT. Taken together with similar functional properties of TAUT from mussel, indicated by our previous study, it is possible that these functional features reflect the internal environment of the molluscs (i.e. higher taurine and NaCl concentrations). Oyster taurine transporter mRNA expression was induced by not only hyper-osmotic stress, similar to other TAUT, but also hypo-osmotic stress. It is speculated that the expression in response to hypo-osmotic stress was induced by a substantial decrease in tissue taurine content following the decrease in the internal osmolality.  相似文献   
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We have isolated a cDNA encoding the taurine transporter from a tilapia (Oreochromis mossambicus) gill cDNA library. Transient expression of the cDNA in COS-7 cell indicates that the clone encodes a Na+- and Cl-dependent and -amino acid-specific taurine transporter. By the transfer of tilapia cultured in freshwater to 70% artificial seawater, plasma osmolality increased by up to 100–135 mOsm/kgH2O along with the marked increase in the taurine transporter mRNA level in all the tissues examined i.e., kidney, stomach, intestine, gill, eye, liver, fin, muscle and brain. In most tissues, time-dependent change in the taurine transporter mRNA level corresponds to that in plasma osmolality. However, fin showed an acute and muscle showed a delayed increase in taurine transporter mRNA compared to changes in plasma osmolality. The taurine transporter mRNA level in tilapia embryos also increased after transfer from freshwater to 100% artificial seawater. Increase in taurine transporter expression leads to the activation of cellular uptake of taurine from plasma and the accumulation of taurine in the cell. Thus the results in the present study suggest that taurine plays an important role as an osmolyte in the ubiquitous tissues of tilapia during high-salinity adaptation.  相似文献   
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以4个耐热性存在差异的菜心品种(系)为试材,研究持续高温胁迫对菜心叶片中渗透调节物质、电解质渗漏率、活性氧的产生与清除的影响。结果表明:短期(1d)高温胁迫下,除过氧化氢酶(CAT)酶活性在耐热性弱的菜心材料中急剧增加,且达到活力最高值外,其它性状如脯氨酸和甜菜碱含量、电解质渗漏率、丙二醛(MDA)含量、O2.产生速率、H2O2含量、超氧化物歧化酶(SOD)和过氧化物酶(POD)酶活性出现小幅度增加,且这些性状的值在4个菜心材料间差异不大;随着高温胁迫处理时间的延长(3~7d),生理指标在4个材料中呈现不同程度的增加,表现出耐热性强的材料的甜菜碱含量、SOD、POD和CAT酶活性均明显高于耐热性弱的材料,电解质渗漏率、MDA含量、O2.产生速率、H2O2含量则明显低于耐热性弱的材料;而脯氨酸含量的高低则未表现出与菜心耐热性强弱的对应关系。  相似文献   
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Nuclear magnetic resonance ‐based metabolomics was applied to study effects of egg aging on ovarian fluid metabolites in rainbow trout, Oncorhynchus mykiss. The eggs of three females were pooled and then assigned to three plastic vials for 18 days in vitro storage at 4°C. Ovarian fluid samples were taken 0, 6, 12 and 18 days after storage. Three groups of metabolites including amino acids, osmolytes and energy metabolites were found to change during storage period. The glucose levels of ovarian fluid showed significant decreases on days 12 and 18 after storage (< .05). For acetoacetate and acetate, significant increases were observed, respectively, on days 12 and 18 after storage (< .05). The creatine levels of ovarian fluid increased significantly on days 12 and 18 after storage (< .05). Lactate levels in ovarian fluid elevated during storage period (< .05). Glycerol levels showed a significant increase on days 12 and 18 after storage (< .05). The values of osmolytes in ovarian fluid (e.g., betaine, taurine, trimethylamine‐N‐oxide, N,N‐dimethylglycine) showed a decreasing trend on day 12 which continued until the end of storage on day 18 (< .05). Almost all amino acids elevated on days 12 and 18 after storage (< .05). After an apparent elevation in isoleucine levels on days 6 and 12, this amino acid decreased on day 18 after storage (< .05). The osmolytes might act as antioxidant against free‐radicals produced as a result of over‐ripening. Glucose can be used as energy resource for eggs and bacteria during ova storage. Also, change pattern of amino acids indicate hydrolysis of proteins as the time of storage increases.  相似文献   
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郭绍霞 《北方园艺》2010,(14):179-181
以芍药‘春晓’(Paeonialactiflora‘Chunxiao’)的切花为试材,采用室内瓶插的方法,在基本瓶插液(3%蔗糖+200 mg/L 8-羟基喹啉+150 mg/L柠檬酸)中分别添加不同浓度的PP333、B9、CCC,通过对渗透调节物质含量的测定,探讨了PP333、B9、CCC对芍药切花采后瓶插水分平衡的影响。结果表明:适宜浓度的PP333、B9、CCC可有效提高切花的可溶性蛋白和可溶性糖的含量;改善切花的水分平衡值,降低脯氨酸含量,减少水分胁迫对切花造成的伤害;从而延缓衰老,延长瓶插寿命。200 mg/L PP333处理的效果最佳,瓶插寿命比对照延长3 d。  相似文献   
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In this study, metabolic responses of Persian sturgeon fingerlings to hyperosmotic condition were investigated by NMR‐based metabolomics. Persian sturgeon fingerlings (n = 2010, mean total weight: 3.2 ± 0.6 g; mean total length: 8.5 ± 1.5 cm) were held in freshwater (FW) for 96 hr and then acclimated in brackish water (BW) (12 g/L) for 24 hr. Blood samples were taken before and after salinity acclimation. The major metabolite changes corresponding to salinity acclimation were related to amino acids, osmolytes and energy metabolites. The plasma glucose levels increased significantly after 24 hr acclimation in BW (p < .05). Other energetic metabolites (acetate, acetoacetate, beta‐hydroxybutyrate, phosphocreatine, creatine, glycerol) showed no significant changes after 24 hr salinity challenge (p > .05). The osmolytes (taurine, trimethylamine‐N‐oxide, choline, N,N‐dimethylglycine) and amino acids (aspartate, glutamate, glutamine, leucine, phenylalanine, β‐alanine, histidine, threonine, cysteine) declined significantly after 24 hr acclimation in BW (p < .05). However, the levels of glycine elevated after 24 hr acclimation in BW (p < .05). Other amino acids including aspargine, isoluecine, Tyrosine, Tryptophan, Valine, and Lysine showed no significant changes after salinity challenge (p > .05). The considerable decreases in almost all plasma amino acids and all osmolytes showed specific importance of these metabolites in osmotic adaptation of fish in BW. Also, it seems that Persian sturgeon fingerlings rely more on oxidation of glucose to meet energetic requirements of osmoregulation than oxidation of lipids, as we observed no detectable changes in metabolites associated with lipid oxidation during osmotic acclimation in BW. Our results may help to understand osmoregulation in a chondrostei fish species from a metabolic approach.  相似文献   
8.
The effects of different salinity levels, including 10–15, 30–35, 70–75, 110–115 and 150–155 ppt, were evaluated on survival and the body amino acids (BAA) of Artemia franciscana. The results were expressed as total essential (TE), non‐essential (NE) and total amino acids (TAA); also, the ratio of the TE to NE (ENAA) on days 3 and 13 of the culture is reported. The study of changes in Artemia BAA showed that with the increase in the water salinity, the TE, NE and TAA increased significantly on days 3 and 13 of the culture. However, the highest ratio of ENAA was observed in the 110 gL?1 salinity treatment on day 3 (1.067 ± 1.25). Regarding the effects of different salinity treatments on the survival rate of Artemia, it was observed that, generally, an increase in the water salinity would reduce the survival rate of this species. This reduction was observed on day 3 of culture in the salinity treatments above 120 (66.66 ± 1.68%) and below 30 gL?1 (89.66 ± 0.34%) and on day 13 of culture in the salinity treatments below 30 (11.86 ± 0.13%) and above 70 gL?1. Basically, it can be concluded that A. franciscana culture at a salinity of 110 gL?1 can lead to the biological enrichment of Artemia in terms of amino acid profile.  相似文献   
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Effect of salinity change on free amino acid content in Pacific oyster   总被引:2,自引:0,他引:2  
ABSTRACT:   In order to identify free amino acids (FAA) that are importantas intracellular osmolytes in Crassostrea gigas , we investigatedthe change in FAA content in the mantle exposed to an abrupt decreaseor increase in salinity. In hypo-osmotic adaptation, most FAA showedremarkable and synchronous decreases from 2 to 8 h, suggestingthat the non-selective efflux of FAA was mainly responsible forthe decrease in FAA. Taurine that accounted for approximately 80% oftotal FAA content contributed most significantly to the hypo-osmoticadaptation. In hyper-osmotic adaptation, significant increases inglycine, alanine, β-alanine, proline, arginine and taurinewere observed. Of these, alanine showed an immediate increase thatis important to short-term adaptation to hyper-osmolality, whiletaurine showed a slower and substantial increase that contributesto a long-term adaptation to hyper-osmolality.  相似文献   
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