Selection of Reference Genes by Quantitative Real-Time PCR for Ruditapes philippinarum Exposed to Nitrite

In order to well investigate the eco-toxicity of nitrite on molluscs, a suitable housekeeper gene was needed for further analysis to qualify the toxicity-related genes. In the present study, the clam Ruditapes philippinarum was used as the target mollusc and cDNAs templates were got from gill tissue RNA of R. philippinarum after nitrite exposure. Six candidate genes were assayed in terms of their expression stabilities by geNorm and NormFinder softwares, followed by a comprehensive weighting comparison. GeNorm analysis indicated that the stability order for the six genes were Actin&gt;CyPA&gt;EF1alpha&gt;Ubi&gt;18S&gt;Tubu. However, a little different order was suggested by the Normfinder software, Actin&gt;Ubi&gt;CyPA&gt;EF1alpha&gt;18S&gt;Tubu. After a comprehensive weighting comparison, the final stability order of the six genes was Actin&gt;CyPA&gt;Ubi&gt;EF1alpha&gt;18S&gt;Tubu. So, the Actin gene was the most suitable reference gene to qualify target genes for their expression levels in the clam R. philippinarum after nitrite exposure.</p

Optimization for antioxidant phycocyanin peptide production by enzyme hydrolysis using response surface methodology

为优化碱性蛋白酶酶解藻蓝蛋白制备抗氧化肽的工艺条件,采用响应面分析法,以超氧阴离子自由基清除率为响应值,研究了[E]/[S]、酶解温度和时间对制备抗氧化肽工艺的影响。结果表明,制备藻蓝蛋白肽的最佳酶解条件为:温度为44.9℃、时间为6.4 h和[E]/[S]为3.6%,此时对超氧阴离子自由基清除率达到75.39%。在该条件下制备的藻蓝蛋白酶解产物(0.5 g/L)还原能力的吸光度为1.03,并达到稳定

响应面法优化酶法制备藻蓝蛋白抗氧化肽的实验研究

为优化碱性蛋白酶酶解藻蓝蛋白制备抗氧化肽的工艺条件,采用响应面分析法,以超氧阴离子自由基清除率为响应值,研究了E/S、酶解温度和时间对制备抗氧化肽工艺的影响。结果表明,制备藻蓝蛋白肽的最佳酶解条件为:温度为44.9℃、时间为6.4 h和E/S为3.6%,此时对超氧阴离子自由基清除率达到75.39%。在该条件下制备的藻蓝蛋白酶解产物(0.5 g/L)还原能力的吸光度为1.03,并达到稳定

羊栖菜多糖微波提取工艺的研究

目的采用微波来提取羊栖菜多糖。方法在单因素试验的基础上,选取提取时间、微波功率和液料比作为优化因素,采用Box-Benhnken试验设计和响应面分析法对羊栖菜多糖的微波提取工艺进行了优化。结果微波提取羊栖菜多糖的最佳工艺参数为:提取时间为9.61 min,微波功率476.29 W,液料比66.66∶1。在此工艺参数下水溶性羊栖菜多糖的提取率为15.58%,与预测值接近。结论同传统的热水浸提法相比,多糖提取率有所提高,且提取时间大大缩短,该优化工艺可用于羊栖菜多糖的提取。

一种综合评价氨态氮对水生动物威胁的方法

本发明涉及评价对水生动物威胁的方法，具体的说是一种综合评价氨态氮对水生动物威胁的方法。以测定水体中氨氮本身毒性和亚硝酸盐毒性的总和作为综合评价氨态氮对水生动物的威胁方法。本发明结合氨态氮在水中的有毒转化形式，并分别对其含量进行测定，综合评价以氨态氮形式胁迫水生生物后，氮元素在水体中转化的各种有毒化合物的总和，避免以其中某一种单一有毒形式(氨态氮或者亚硝酸氮)评价受污染水体的安全性，造成致毒物质遗漏，或者在后续的环境监测生物标志物筛选及致毒机制研究过程中，生物标志物及致毒机理与环境致毒物质的不一致

Selection of Reference Genes for Toxicological Mechanism Research on Ruditapes philippinarum Exposed to Ammonia Nitrogen

In order to analyze the transcriptome data accurately and systemically, a suitable reference gene is necessary. In the present study, geNorm and Normfinder softwares were used to analyze the expression stabilities of six candidate reference genes of Ruditapes philippinarum after ammonia nitrogen exposure for 30 days. The reference genes included 18S rRNA (18S), beta-actin (Actin), beta-tubulin (Tubu), elongation factor 1-alpha (EF1alpha), cyclophilin A (CyPA) and Ubiquitin (Ub). Based on a 50-times diluted cDNA in gills as the quantitative real-time PCR template, the geNorm software analysis demonstrated that the expression stabilities of the six candidate reference gene after NH_3-N exposure were as follows: EF1alpha>CyPA>Actin>Tubu>Ub>18S, and EF1alpha and CyPA were the best two ones among the six reference genes. A little different order was detected by the NormFinder software as follows: EF1alpha>Actin>Tubu>CyPA>Ub>18S. And EF1alpha was recommended as the optimal reference gene. As an assay, EF1alpha and CyPA were employed to examine one target unigene by qRT-PCR respectively. Final results showed that the variation trend detected by EF1alpha was more consistent with the foldchange value of the transcriptome. So EF1alpha was selected as the housekeeping gene to analyze the transcriptome data of gills in Ruditapes philippinarum after ammonia nitrogen exposure

Screening of marine bacterium producing carrageenase and its enzymatic properties

从病烂的海洋植物中分离到一株高产卡拉胶酶的海洋细菌YK-5,革兰阴性,初步鉴定为黄杆菌属(Flavobacterium)中的一个种。该菌株在温度28℃,培养基起始pH8.5条件下培养48h产生碱性卡拉胶酶活力高达149.8U/mL。酶学性质的初步研究显示,YK-5产生的卡拉胶酶最适反应pH值为9.0,在pH8.0~11.0范围内具有较高的酶活性和较好的稳定性;最适反应温度为30℃,且在40℃以下具有较高的温度稳定性。经传代培养证实该菌株遗传性能稳定。

Selection of Reference Genes for Toxicological Mechanism Research on Ruditapes phUippinarum Exposed to Ammonia Nitrogen

为了准确和系统地分析NH_3-N对菲律宾蛤仔（Ruditapes philippinarum）毒性的分子机制,并对相关基因的转录组学数据进行验证,利用ge Norm和Normfinder这2种软件,以暴露30 d中不同时间点的鳃组织c DNA为模板,从18S r RNA（18S）、beta-actin（Actin）、beta-tubulin（Tubu）、elongation factor 1-alpha（EF1α）、cyclophilin A（Cy PA）、Ubiquitin（Ub）等6个备选管家基因中,筛选可以稳定表达的内参基因,作为转录组学分析的内参基因。以稀释50倍的鳃组织c DNA模板作为检测模板,ge Norm软件分析获得6对备选内参基因的表达稳定性依次为：EF1α〉Cy PA〉Actin〉Tubu〉Ub〉18S,较优内参为EF1α和Cy PA;Norm Finder软件分析获得6对备选内参基因的表达稳定性为：EF1α〉Actin〉Tubu〉Cy PA〉Ub〉18S,最优内参基因为EF1α。为了验证上述筛选结果,分别以EF1α和Cy PA作为内参基因研究unigene1的表达趋势,发现以EF1α为内参基因时,unigene1的q RT-PCR的表达趋势与其转录组表达倍数的变化趋势一致。因此确定NH_3-N暴露菲律宾蛤仔后,鳃组织中表达最为稳定的内参基因为EF1α

JUNO Sensitivity on Proton Decay p→νˉK+p\to \bar\nu K^+ Searches

The Jiangmen Underground Neutrino Observatory (JUNO) is a large liquid scintillator detector designed to explore many topics in fundamental physics. In this paper, the potential on searching for proton decay in $p\to \bar\nu K^+$ mode with JUNO is investigated.The kaon and its decay particles feature a clear three-fold coincidence signature that results in a high efficiency for identification. Moreover, the excellent energy resolution of JUNO permits to suppress the sizable background caused by other delayed signals. Based on these advantages, the detection efficiency for the proton decay via $p\to \bar\nu K^+$ is 36.9% with a background level of 0.2 events after 10 years of data taking. The estimated sensitivity based on 200 kton-years exposure is $9.6 \times 10^{33}$ years, competitive with the current best limits on the proton lifetime in this channel