It is a common issue in the processing industry of crayfish that flavored crayfish stored at room temperature is perishable.In order to establish an effective putrid prediction mechanism,high-throughput sequencing and...It is a common issue in the processing industry of crayfish that flavored crayfish stored at room temperature is perishable.In order to establish an effective putrid prediction mechanism,high-throughput sequencing and solid phase microextraction gas chromatography-mass spectrometry(SPME-GCMS)were used to analyse the microbial community structure and volatile flavor compounds of normal and putrid crayfish.The results showed that Aeromonas(57%),Macrococcus(7.7%),Vibrio sp.(6.6%),Acinetobacter(5%),Citrobacter(4.9%)and Enterobacter(1.49%)were the main bacterial genus in the refrigerated fresh crayfish(HNA).And Staphylococcus(17.04%),Aeromonas(4.46%),Xanthomonas(4.16%),Streptococcus(4.62%)and Enterococcus(2.77%)were the main bacterial genus in the marinated and refrigerated crayfish(HND).With the spoilage of samples(HNE and HNC),the diversity of bacteria decreased,and the specific spoilage bacteria grew rapidly,mainly Enterococcus,Bacillus,Lactobacillus,Leuconostoc,Weissella.Meanwhile,the volatile compounds in non-spoilage sample(HNA and HND)were mainly alkane compounds,aldehydes compound and esters compounds;and the volatile compounds in spoilage samples were mainly alcohols,acids,benzene compounds,terpenoids,N-containing compounds,S-containing compounds and ethers.This indicated that the contents and types of volatile compounds changed with the sample spoilage and deterioration.Correlation analysis results showed that Enterococcus,Lactobacillus and Bacillus were significantly positively correlated with alcohols,acids,benzene,terpenoids,N-containing compounds,S-containing compounds and ether compounds,while Aeromonas,Megasphaera,Acinetobacter,Citrobacter and Vibrio were significantly positively correlated with alkane compounds and esters compounds,and Leuconostoc were significantly positively correlated with alcohol compounds.These results can provide a theoretical guidance for the storage of cooked flavor crayfish at room temperature.展开更多
基于转座酶和高通量测序的染色质分析技术(assay for transposase-accessible chromatin using sequencing,ATAC-seq)是近年来较为热门的一项用于检测染色质开放性的表观遗传组学技术。为确定适用于人原代免疫细胞的ATAC-seq实验方法,...基于转座酶和高通量测序的染色质分析技术(assay for transposase-accessible chromatin using sequencing,ATAC-seq)是近年来较为热门的一项用于检测染色质开放性的表观遗传组学技术。为确定适用于人原代免疫细胞的ATAC-seq实验方法,本研究探寻细胞裂解条件,发现0.1%NP-40能温和且较为彻底地裂解细胞。具体方法为使用Tn5转座酶切割染色质并连接测序接头,利用PCR扩增建库;运用2100Bioanalyzer毛细管电泳和统计分析文库中的DNA片段,得到片段呈周期性排布的ATAC-seq文库分布模式。使用一系列生物信息学工具确定文库质量,发现样本总比对率大于94%,线粒体基因组百分率低于38%,所得ATAC-seq信号在转录起始位点附近有明显富集,技术重复间可重复率约为80%。以上从多个维度表明实验及文库制备的整个过程质量良好,是较为理想的用于处理人原代免疫细胞的ATAC-seq实验方法。展开更多
Nanopores for DNA sequencing have drawn much attention due to their potentials to achieve amplification-free, low-cost, and high-throughput analysis of nuclei acids. The material configuration and fabrication of the n...Nanopores for DNA sequencing have drawn much attention due to their potentials to achieve amplification-free, low-cost, and high-throughput analysis of nuclei acids. The material configuration and fabrication of the nanopore has become one important consideration in the nanopore based DNA sequencing research. Among various materials, the newly emerged graphene has brought more opportunities to the development of sequencing technology because of its unique structures and properties. This review mainly focuses on the experimental aspects of graphene nanopore research including the nanopore fabrication methods and processes. Meanwhile, the challenges in the present graphene nanopore research including hydrophobicity, translocation velocity and noise are also addressed and discussed.展开更多
文摘It is a common issue in the processing industry of crayfish that flavored crayfish stored at room temperature is perishable.In order to establish an effective putrid prediction mechanism,high-throughput sequencing and solid phase microextraction gas chromatography-mass spectrometry(SPME-GCMS)were used to analyse the microbial community structure and volatile flavor compounds of normal and putrid crayfish.The results showed that Aeromonas(57%),Macrococcus(7.7%),Vibrio sp.(6.6%),Acinetobacter(5%),Citrobacter(4.9%)and Enterobacter(1.49%)were the main bacterial genus in the refrigerated fresh crayfish(HNA).And Staphylococcus(17.04%),Aeromonas(4.46%),Xanthomonas(4.16%),Streptococcus(4.62%)and Enterococcus(2.77%)were the main bacterial genus in the marinated and refrigerated crayfish(HND).With the spoilage of samples(HNE and HNC),the diversity of bacteria decreased,and the specific spoilage bacteria grew rapidly,mainly Enterococcus,Bacillus,Lactobacillus,Leuconostoc,Weissella.Meanwhile,the volatile compounds in non-spoilage sample(HNA and HND)were mainly alkane compounds,aldehydes compound and esters compounds;and the volatile compounds in spoilage samples were mainly alcohols,acids,benzene compounds,terpenoids,N-containing compounds,S-containing compounds and ethers.This indicated that the contents and types of volatile compounds changed with the sample spoilage and deterioration.Correlation analysis results showed that Enterococcus,Lactobacillus and Bacillus were significantly positively correlated with alcohols,acids,benzene,terpenoids,N-containing compounds,S-containing compounds and ether compounds,while Aeromonas,Megasphaera,Acinetobacter,Citrobacter and Vibrio were significantly positively correlated with alkane compounds and esters compounds,and Leuconostoc were significantly positively correlated with alcohol compounds.These results can provide a theoretical guidance for the storage of cooked flavor crayfish at room temperature.
文摘基于转座酶和高通量测序的染色质分析技术(assay for transposase-accessible chromatin using sequencing,ATAC-seq)是近年来较为热门的一项用于检测染色质开放性的表观遗传组学技术。为确定适用于人原代免疫细胞的ATAC-seq实验方法,本研究探寻细胞裂解条件,发现0.1%NP-40能温和且较为彻底地裂解细胞。具体方法为使用Tn5转座酶切割染色质并连接测序接头,利用PCR扩增建库;运用2100Bioanalyzer毛细管电泳和统计分析文库中的DNA片段,得到片段呈周期性排布的ATAC-seq文库分布模式。使用一系列生物信息学工具确定文库质量,发现样本总比对率大于94%,线粒体基因组百分率低于38%,所得ATAC-seq信号在转录起始位点附近有明显富集,技术重复间可重复率约为80%。以上从多个维度表明实验及文库制备的整个过程质量良好,是较为理想的用于处理人原代免疫细胞的ATAC-seq实验方法。
基金supported by the National Natural Science Foundation of China (81471697)the Key Technology R&D Program of Hubei Province (2014BBB003)+1 种基金Yellow Crane Talent (Science & Technology) Program of Wuhan City and Applied Basic Research Program of Wuhan City (2016060101010044, 2016060101010048)the Fundamental Research Funds for the Central Universities (2016YXMS253)
文摘Nanopores for DNA sequencing have drawn much attention due to their potentials to achieve amplification-free, low-cost, and high-throughput analysis of nuclei acids. The material configuration and fabrication of the nanopore has become one important consideration in the nanopore based DNA sequencing research. Among various materials, the newly emerged graphene has brought more opportunities to the development of sequencing technology because of its unique structures and properties. This review mainly focuses on the experimental aspects of graphene nanopore research including the nanopore fabrication methods and processes. Meanwhile, the challenges in the present graphene nanopore research including hydrophobicity, translocation velocity and noise are also addressed and discussed.
