斑节对虾Chitinase-2基因的克隆及其在蜕皮和幼体发育过程中的表达分析

研究以斑节对虾(Penaeus monodon)转录组获得的几丁质酶基因(Pm Chi)片段,运用RACE技术克隆了PmChi基因c DNA全长,命名为PmChi-2。PmChi-2基因c DNA全长2 050 bp,其中5'-非编码区(5'-UTR)144 bp、3'-UTR 319 bp和开放阅读框(ORF)1 587 bp,编码528个氨基酸。生物信息学分析显示,PmChi-2与其他甲壳动物Chi-2的相似性为78%~97%。实时荧光定量PCR结果显示,PmChi-2在蜕皮前期(D期)表皮中表达水平最高,在胃、鳃、腹神经节和眼柄中表达水平依次降低,在其他组织(肝胰腺、肠、肌肉、心脏)中几乎不表达。不同蜕皮阶段,PmChi-2在鳃、胃和表皮3种组织中的表达变化模式基本一致,均在蜕皮期(E期)表达量最低,而最高表达量在鳃中出现在蜕皮后期(A期),在胃和表皮中为D期。幼体不同发育阶段分析揭示PmChi-2 mRNA在幼体发育阶段的无节幼体到糠虾幼体第二期表达量维持在一个低水平,在糠虾幼体第三期PmChi-2 mRNA表达水平显著升高,在仔虾期又显著下降,推测PmChi-2 mRNA可能与斑节对虾幼体发育密切相关。研究结果表明PmChi-2基因可能在斑节对虾蜕皮以及幼体的变态发育中发挥重要作用,为深入研究斑节对虾几丁质酶发育调控提供了重要信息。     

用液相色谱串联质谱法测定渔业水样中6种农药的含量

本文建立了一种快速检测渔业水质样本中酰胺类除草剂乙草胺、丙草胺、丁草胺、三嗪类除草剂莠去津、烟碱类杀虫剂噻虫嗪、三唑类杀菌剂苯醚甲环唑6种农药含量的液相色谱串联质谱法。采用乙腈-水-甲酸梯度洗脱、电喷雾电离方式、多反应监测模式测定考察检出限、线性范围、日内精密度及日间精密度。在三种加标浓度下,该方法的回收率为78.2%~104.7%。用液相色谱-四级杆-飞行时间质谱对疑似目标物质进行定性,用精确质量数、同位素丰度比和二级碎片解析方式等解析定性结构。该方法能够满足检测这六种农药的要求,能准确定性,自建的谱库可为渔业污染事故鉴定和水产品质量安全风险评估做支撑。     

水稻苗期根系铵钾离子吸收的交互作用研究

【目的】为探讨水稻幼苗根系NH_4~+、K~+吸收的交互作用,深化水稻养分吸收理论,【方法】采用溶液培养的方法,对低钾及高钾浓度下水稻在有铵和无铵时的K~+吸收动力学特征进行了研究,对不同钾浓度下水稻根系NH_4~+的吸收速率进行了比较。【结果】1)当K~+0.2 mmol/L时,水稻根系通过高亲和转运系统吸收K~+服从Michaelich-Menten动力学方程;NH_4~+的存在显著降低K~+的最大吸收速率(Vmax),且降幅随着NH_4~+浓度的增加而增大;NH_4~+对水稻根表载体与K~+的亲和力(Km)影响较小,在1.62 mmol/L NH_4~+浓度下,水稻品种齐粒丝苗和沪科3号的Km分别下降了12.33%和16.46%,远低于Vmax 47.30%和39.21%的降幅。2)当K~+0.5 mmol/L时,水稻根系K~+低亲和转运系统发挥作用,K~+吸收速率随浓度的增加而不断增加,呈不饱和特征;但在相同K~+浓度下,水稻根系的K~+吸收速率随NH_4~+浓度的增加而下降。3)水稻根系对NH_4~+的吸收速率随着NH_4~+浓度的增加而增加;在相同NH_4~+浓度下,水稻根系对NH_4~+的吸收速率受K~+浓度的影响很小。【结论】NH_4~+抑制水稻苗期根系K~+的高亲和转运和低亲和转运,NH_4~+对K~+高亲和吸收的影响主要是由于铵竞争细胞膜上的钾载体所致;外界K~+浓度的变化对水稻幼苗的NH_4~+吸收速率影响很小。水稻铵钾的交互作用主要表现在NH_4~+对K~+吸收的抑制作用。     

Characterization of <Emphasis Type="Italic">kiss2</Emphasis> and <Emphasis Type="Italic">kissr2</Emphasis> genes and the regulation of kisspeptin on the HPG axis in <Emphasis Type="Italic">Cynoglossus semilaevis</Emphasis>

Reproduction allows organisms to produce offspring. Animals shift from immature juveniles into mature adults and become capable of sexual reproduction during puberty, which culminates in the first spermiation and sperm hydration or ovulation. Reproduction is closely related to the precise control of the hypothalamic–pituitary–gonadal (HPG) axis. Kisspeptin peptides are considered as the important regulator of HPG axis in mammalian. However, the current understanding of kisspeptin in flatfish is not comprehensive. In this study, we cloned and analyzed the kiss2 and kissr2 genes in Cynoglossus semilaevis. Interesting alternative splicing in the 5′-untranslated regions (UTR) of the Cskissr2 gene was found. The expression profiles of Cskiss2 and Cskissr2 showed relative high messenger RNA (mRNA) levels at the late gastrula stage during embryonic development, at total length = 40 mm during early gonadal differentiation, and in the brains and gonads of all investigated tissues. These results suggested that the kisspeptin system participated in embryogenesis and in the regulation of gonadal differentiation and development. Considering that the control and regulatory mechanisms of kisspeptin in the central reproductive axis are still unclear, we documented that the intramuscular injection of kisspeptin caused different sGnRH and cGnRH mRNA levels in a dose- and tissue-dependent manner. The mRNA expressions of FSH and LH were stimulated in the ovary and were inhibited in the testis under the kisspeptin treatments. These results provided foundations for understanding the roles of kisspeptin in the neuroendocrine system in fish. The manipulation of the kisspeptin system may provide new opportunities to control the gonadal development and even reproduction in fish.     

烟酰胺腺嘌呤二核苷酸(NAD)合成途径和水稻叶片早衰

叶片是植物进行光合作用的主要场所,其衰老由内源遗传发育信号和外界环境胁迫所启动,是一个非常复杂有序的调控过程。烟酰胺腺嘌呤二核苷酸(nicotinamide adenine dinucleotide,NAD)是脱氢酶的辅酶,在糖酵解、糖异生、三羧酸循环以及呼吸链等代谢中发挥着不可替代的作用。最新研究表明,水稻NAD生物合成参与调控沉默信息调控因子Sirtuins的生物活性、组蛋白H3K9去乙酰化、植物激素茉莉酸(JA)和叶片衰老。本文综述了有关水稻叶片衰老的细胞生理特征、Sirtuins酶活、NAD生物合成以及水稻早衰的OsSRT1-NAD调控途径和OsSRT1-Me OH-JA调控途径,以期阐明水稻叶片衰老的分子机理及其调控途径,为高产育种提供相应的理论参考。     

基于高通量测序技术分析石蝉草内生细菌多样性

以石蝉草根、茎、叶为材料,采用Illumina Mi Seq高通量测序技术研究石蝉草内生细菌多样性。结果表明,根、茎、叶样品共测得167个OTUs,归属于11个门,分别为变形菌门、Ignavibacteriae、芽单胞菌门、梭杆菌门、厚壁菌门、异常球菌-栖热菌门、绿弯菌门、拟杆菌门、放线菌门和酸杆菌门,各样品的菌群组成和多样性虽有差异,但以变形菌门为优势菌群,约占62.48%~93.24%。在各样品菌群丰度最高的10个OTUs中,叶部优势群落芽孢杆菌属、根部特有群落粘球菌目与石蝉草中具有抗炎、抗肿瘤活性的物质存在潜在相关性。     

气象因子对寒地水稻鞘腐病发生的影响

为明确主要气象因子对黑龙江省水稻主产区水稻鞘腐病发生的影响,从2007年开始连续10年进行定点调查,收集水稻鞘腐病发生时期的气象因子及病情指数,采用通径分析及逐步回归的方法,对影响水稻鞘腐病病情指数的气象因子进行了研究。结果表明,8月份的平均温度是对水稻鞘腐病影响最大的气象因子,其次为8月份的平均降雨量和9月份的平均日照时数。试验结果为适期施药防治水稻鞘腐病奠定了基础。     

新媒体时代社会主义核心价值观群众认同的路径探析

随着网络信息技术的发展,手机、平板电脑、数字电视等新媒体产品在人民群众中得到了广泛的应用,从而使得信息传播的互动性增强,出现了去中心化的趋势,为社会主义核心价值观的群众认同路径提供了机遇和挑战.如何利用新媒体时代创新社会主义核心价值观的传播载体,丰富传播内容、净化传播环境对于增强社会主义核心价值观的群众认同具有重要意义.     

长江口凤鲚雌雄成体营养成分分析与比较

对长江口雌性和雄性成体凤鲚(Coilia mystus)整体的营养成分和品质进行了分析与评价。结果显示,雌、雄凤鲚整体水分、粗蛋白、粗脂肪和灰分的质量分数分别为78.36%±1.41%、76.70%±1.20%,14.25%±1.05%、15.18%±0.12%,4.61%±1.78%、4.84%±0.27%和2.22%±0.38%、2.97%±0.64%,雌、雄间均不具有显著性差异(P0.05)。雌、雄均含有18种组成蛋白质的氨基酸,总量分别为66.20%±5.78%和65.93%±6.35%(质量分数,干样),其中8种必需氨基酸(EAA)总量分别是25.07%±1.93%和23.95%±2.21%,两者间不具有显著性差异(P0.05),分别占氨基酸总量的37.90%和36.33%,雌、雄凤鲚的必需氨基酸组成比例均符合FAO/WHO的标准。色氨酸是雌、雄凤鲚整体的第一限制性氨基酸,蛋氨酸+胱氨酸是第二限制性氨基酸,雌、雄凤鲚整体的EAAI分别为70.73和66.99,4种鲜味氨基酸总量分别为25.99%±2.53%和26.02%±2.3%(质量分数,干样)。雌性凤鲚的饱和脂肪酸(SFA)含量显著低于雄性(P0.05),而多不饱和脂肪酸(PUFA)含量则显著高于雄性(P0.05),单不饱和脂肪酸(MUFA)两者无显著差异(P0.05)。雌性凤鲚脂肪酸中EPA与DHA质量分数分别为5.70%±0.24%和10.15%±1.31%,显著高于雄性凤鲚的1.05%±0.40%和1.06%±0.44%。结果表明,长江口雌、雄成体凤鲚整体的氨基酸较均衡,而雌性凤鲚的脂肪酸营养更为丰富,比雄性凤鲚具有更好的食用价值与保健作用。     

Characterization of microbial communities in intensive GIFT tilapia (Oreochromis niloticus) pond systems during the peak period of breeding

Aquaculture pond is a complex ecosystem where the microorganisms in the sediments, in the animal intestinal tract and in water interact with each other to influence the water quality and health of aquatic animals. In order to understand the spatial distribution and relationship of microbial communities in intensively farmed genetically improved farmed tilapia (GIFT, Oreochromis niloticus), 454 high‐throughput pyrosequencing was applied to analyse the 16S rRNA gene of bacteria in intensive GIFT ponds in Wuxi City, Jiangsu Province, China. A total of 72 747 initial sequences were obtained from four depths of pond water, from tilapia large intestines and from pond sediment. The most common phylum in all samples was Proteobacteria, Actinobacteria and Cyanobacteria were the most abundant in water, Fusobacteria and Firmicutes in the large intestine and Chloroflexi in sediment samples. The sediment microbial community structure was comparatively similar to that of the tilapia large intestine. The microbial communities from different water depths were somewhat similar, especially the three most shallow samples, although the abundance of Actinobacteria gradually decreased with increased water depth. This data offer a preliminary exploration of the response mechanisms of the bacterial communities to aquafarming and contributes to the understanding of the status of bacterial communities of tilapia pond systems during the peak period of breeding from the aspect of their spatial distributions.