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为探索贝类LAP3基因的结构和功能特征以及在生长发育过程中的作用,利用cDNA末端快速扩增（RACE）法获得文蛤LAP3（Mm-LAP3）基因的cDNA全长序列,并对其生物信息学、组织及发育时期表达特征进行了分析。结果显示,Mm-LAP3基因cDNA全长2 037 bp,ORF区1 254 bp,编码417个氨基酸;Mm-LAP3蛋白由Peptidase_M17超家族序列的N-端结构域和Peptidase_M17催化结构域组成。荧光实时定量PCR结果表明,Mm-LAP3基因在文蛤成体6个组织和幼体10个发育时期中均有表达,其中在斧足中的表达量显著高于其他组织（P<0.05）,这与斧足蛋白含量丰富、代谢旺盛相关;在幼体10个发育时期中的表达量呈现逐渐升高的趋势,在D形幼虫时期达到最高,随后又有所降低,推测Mm-LAP3基因在早期发育时期参与了某些组织器官的形成。 相似文献
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广东南澳岛大型海藻龙须菜与浮游植物对营养盐的竞争利用 总被引：2，自引：0，他引：2
广东南澳岛近海是我国龙须菜养殖的重要基地。为了探究龙须菜养殖对藻华防治的贡献,分别于2016年3月、5月和6月在广东南澳岛北部海域不同养殖功能海区进行采样,研究龙须菜养殖前后海水中营养盐含量和结构的变化,分析不同粒径的浮游生物对有机营养盐的水解利用,探讨龙须菜养殖对浮游植物竞争利用营养盐和生长产生的影响。结果表明,研究海区水质较清洁,无机氮磷含量较低,春季至夏季,随着龙须菜和浮游植物生物量增加,溶解无机磷(dissolved inorganic phosphorus,DIP)浓度不断下降,至6月南澳海区成为磷限制海域。在5月龙须菜生长高峰期,龙须菜养殖区和龙须菜鲍鱼混养区的DIP浓度显著低于鲍鱼区和非养殖区,龙须菜养殖区的叶绿素a浓度明显低于其他区域,亮氨酸氨肽酶(leucine amino peptide,LAP)和碱性磷酸酶(alkaline phosphatase,AP)活性显著升高,表明龙须菜养殖区浮游植物受到较为明显的营养胁迫。而龙须菜收割后,该养殖区的叶绿素a含量则显著上升,甚至高于其他区域。该结果表明在南澳岛海域,龙须菜养殖通过营养竞争关系(尤其是磷)抑制浮游植物的生长,大规模龙须菜养殖可能有助于抑制有害藻华的发生。 相似文献
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海水胞外酶活性可以指示有机物的分布特征以及微生物的营养状况。我们测定了2017年3月25日至4月15日黄海和东海44个大面站以及2018年4月28日至29日胶州湾湾口附近海域10个站位表层海水中的8种胞外酶活性并研究了其分布特征。2017年春季黄、东海表层海水中碱性磷酸酶和脂肪酶活性较高,高值区出现在苏北沿岸和南黄海中部,碱性磷酸酶与磷酸盐浓度之间呈正相关。其余6种酶(肽酶、几丁质酶、纤维素酶、α-D-葡萄糖苷酶、β-D-半乳糖苷酶、木糖苷酶)活性高值区出现在长江口以东的外海,东海的β-D-半乳糖苷酶、木糖苷酶平均酶活性显著高于黄海。8种酶活性平均值排列顺序由大到小为:碱性磷酸酶、脂肪酶、肽酶、几丁质酶、α-D-葡萄糖苷酶、β-D-半乳糖苷酶、纤维素酶、木糖苷酶,其中α-D-葡萄糖苷酶和β-D-半乳糖苷酶的活性基本一致。2018年春季胶州湾附近海域海水中碱性磷酸酶、脂肪酶、木糖苷酶活性分布为近岸高于远岸,几丁质酶活性为近岸低于远岸。8种酶活性平均值排列顺序由大到小为:碱性磷酸酶、脂肪酶、肽酶、木糖苷酶、α-D-葡萄糖苷酶、β-D-半乳糖苷酶、几丁质酶、纤维素酶,其中几丁质酶和纤维素酶的活性基本一致。黄海的碱性磷酸酶和脂肪酶平均酶活性均显著高于东海和胶州湾附近海域。糖类水解酶(几丁质酶、纤维素酶、α-D-葡萄糖苷酶、β-D-半乳糖苷酶、木糖苷酶)平均酶活性在黄海最低。本文的结果对于理解中国近海海水有机碳的分布、浮游植物及异养细菌对有机碳的降解具有重要意义。 相似文献
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Dietary leucine requirement for juvenile large yellow croaker, Pseudosciaena crocea Richardson 1846 (initial body weight 6.0 g ± 0.1 g) was determined using dose-response method. Six isonitogenous (crude protein
43%) and isoenergetic (19 kJ g−1) practical diets containing six levels of leucine (Diets 1–6) ranging from 1.23% to 4.80% (dry matter) were made at about
0.7% increment of leucine. Equal amino acid nitrogen was maintained by replacing leucine with glutamic acid. Triplicate groups
of 60 individuals were fed to apparent satiation by hand twice daily (05:00 and 17:30). The water temperature was 26–32°C,
salinity 26–30 and dissolved oxygen approximately 7 mg L−1 during the experimental period. Final weight (FW) of large yellow croaker initially increased with increasing level of dietary
leucine but then decreased at further higher level of leucine. The highest FW was obtained in fish fed diet with 3.30% Leucine
(Diet 4). FW of fish fed the diet with 4.80% Leucine (Diet 6) was significantly lower than those fed Diet 4. However, no significant
differences were observed between the other dietary treatments. Feed efficiency (FE) and whole body composition were independent
of dietary leucine contents (P > 0.05). The results indicated that leucine was essential for growth of juvenile large yellow croaker. On the basis of FW,
the optimum dietary leucine requirement for juvenile large yellow croaker was estimated to be 2.92% of dry matter (6.79% of
dietary protein). 相似文献
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首次从中国明对虾(Fenneropenaeus chinensiss)肌肉组织中克隆得到TOR基因的cDNA,全长共7 638 bp,开放阅读框7 389 bp,编码2 462个氨基酸。氨基酸序列比对和结构域分析均证实其为目前已知的TOR激酶的同源蛋白。应用实时定量PCR的方法研究TOR在中国明对虾中的组织分布特异性,以及注射等浓度的亮氨酸和精氨酸后,肌肉组织中TOR mRNA表达水平在3,6,12,24 h的变化,探讨营养水平对TOR基因表达的影响。结果显示,注射亮氨酸和精氨酸24 h的对虾TOR mRNA表达量是对照组的3~4倍,显著升高(P0.05),证实氨基酸对TOR的表达具有调节作用。 相似文献
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在双壳类软体动物中, 血淋巴细胞介导的吞噬作用是清除入侵微生物的主要方式。本文在长牡蛎中鉴定了一个包含富含亮氨酸重复序列(Leucine-rich repeat, LRR)结构域的新型基因, 命名为CgLRRC69。对该基因的组织分布分析表明, CgLRRC69 mRNA在血淋巴细胞、鳃、肌肉、外套膜、心脏、消化腺和性腺中广泛表达。副溶血弧菌感染可以显著地刺激CgLRRC69在血淋巴细胞中表达, 并且在感染后6h达到峰值。同时, 酶联免疫吸附实验发现CgLRRC69可以特异性结合脂多糖(lipopolysaccharide, LPS), 表明它可能在免疫防御中有功能。吞噬实验结果显示, CgLRRC69重组蛋白可以显著地提高血淋巴细胞的吞噬能力; RNAi干扰CgLRRC69在牡蛎体内的表达, 显著降低了血淋巴细胞对细菌的清除能力。因此, 这些结果揭示了CgLRRC69作为一种新型模式识别受体, 可以特异性识别革兰氏阴性菌的主要成分LPS, 通过调理作用有效地清除细菌。 相似文献
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Bacterial production is one of the key parameters to evaluate bacterial role in ocean carbon fluxes.Estimation of bacterial production requires the leucine-to-carbon conversion factors that change widely across environments.However,empirical leucine-to-carbon conversion factors(e CFs) are seldom determined in situ because of time consuming and little is known on regulating factors for the e CFs.During May 2015 to January 2016,fourteen dilution experiments were conducted,from the Zhujiang(Pearl River) Estuary to the coast of the northern South China Sea,to determine spatiotemporal variability in the e CFs and its potential controlling factors along an environmental gradient.The e CFs showed clear spatial variations with the highest(1.27–1.69(kg C)/(mol Leu)) in low salinity waters(salinity15),intermediate(1.03–1.25(kg C)/(mol Leu)) in moderate salinity(salinity of 15–25),and the lowest(0.48–0.85(kg C)/(mol Leu)) in high salinity waters(salinity25).Substrate availability was responsible for spatial variability in the e CFs.In the pristine coastal waters,low e CFs was related to substrate limitation and leucine incorporated was respired to maximize the survival rather than bacterial production.Hence,the e CFs measurement was needed for estimating bacterial production accurately in various marine environments. 相似文献
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