223 research outputs found

    Biochemical changes in low-salt fermentation of solidstate soy sauce

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    Low-salt solid-state fermentation soy sauce was prepared with defatted soy bean and wheat bran. Biochemical changes during the aging of the soy sauce mash were investigated. Results show that after a 15-day aging period, the contents of total nitrogen, formol titration nitrogen, free amino acids, reducing sugar, total sugar and the brown color were increased. However pH was decreased during the fermentation period. Furthermore contents of free amino acids in low-salt solid-state fermentation soy sauce fluctuated during the fermentation period with most of the free amino acids increased. The analysis of free amino acid composition shows that the contents of glutamic acid, aspartic acid, alanine and leucine were higher than other amino acids. Therefore it means that these amino acids may contribute to the taste and flavor of low-salt solid-state fermentation soy sauce. Analyzing the biochemical change in the fermented process of soy sauce is helpful to find out the shortcoming of lowsalt solid-state fermented soy sauce. It is of benefit in improving the quality of low-salt solid-state fermented soy sauce

    Heritable and Precise Zebrafish Genome Editing Using a CRISPR-Cas System

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    We have previously reported a simple and customizable CRISPR (clustered regularly interspaced short palindromic repeats) RNA-guided Cas9 nuclease (RGN) system that can be used to efficiently and robustly introduce somatic indel mutations in endogenous zebrafish genes. Here we demonstrate that RGN-induced mutations are heritable, with efficiencies of germline transmission reaching as high as 100%. In addition, we extend the power of the RGN system by showing that these nucleases can be used with single-stranded oligodeoxynucleotides (ssODNs) to create precise intended sequence modifications, including single nucleotide substitutions. Finally, we describe and validate simple strategies that improve the targeting range of RGNs from 1 in every 128 basepairs (bps) of random DNA sequence to 1 in every 8 bps. Together, these advances expand the utility of the CRISPR-Cas system in the zebrafish beyond somatic indel formation to heritable and precise genome modifications

    Efficient genome editing in zebrafish using a CRISPR-Cas system

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    In bacteria, foreign nucleic acids are silenced by clustered, regularly interspaced, short palindromic repeats (CRISPR)--CRISPR-associated (Cas) systems. Bacterial type II CRISPR systems have been adapted to create guide RNAs that direct site-specific DNA cleavage by the Cas9 endonuclease in cultured cells. Here we show that the CRISPR-Cas system functions in vivo to induce targeted genetic modifications in zebrafish embryos with efficiencies similar to those obtained using zinc finger nucleases and transcription activator-like effector nucleases

    CAUSEL: an epigenome- and genome-editing pipeline for establishing function of noncoding GWAS variants

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    The vast majority of disease-associated single nucleotide polymorphisms (SNPs) mapped by genome-wide association studies (GWAS) are located in the non-protein coding genome, but establishing the functional and mechanistic roles of these sequence variants has proven challenging. Here, we describe a general pipeline in which candidate functional SNPs are first evaluated by fine-mapping, epigenomic profiling, and epigenome editing and then interrogated for causal function by using genome editing to create isogenic cell lines. To validate this approach, we analyzed the 6q22.1 prostate cancer risk locus and identified rs339331 as the top scoring SNP. Epigenome editing confirmed that rs339331 possessed regulatory potential. Using transcription activator-like effector nuclease (TALEN)-mediated genome-editing, we created a panel of isogenic 22Rv1 prostate cancer cell lines representing all three genotypes (TT, TC, CC) at rs339331. Introduction of the “T” risk allele increased transcription of the RFX6 gene, increased HOXB13 binding at the rs339331 region, and increased deposition of the enhancer-associated H3K4me2 histone mark at the rs339331 region. The cell lines also differed in cellular morphology and adhesion, and pathway analysis of differentially expressed genes suggested an influence of androgens. In summary, we have developed and validated a widely accessible approach to establish functional causality for non-coding sequence variants identified by GWAS

    Efficient In Vivo Genome Editing Using RNA-Guided Nucleases Nature Biotechnology

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    Abstract Clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated (Cas) systems have evolved in bacteria and archaea as a defense mechanism to silence foreign nucleic acids of viruses and plasmids. Recent work has shown that bacterial type II CRISPR systems can be adapted to create guide RNAs (gRNAs) capable of directing site-specific DNA cleavage by the Cas9 nuclease in vitro. Here we show that this system can function in vivo to induce targeted genetic modifications in zebrafish embryos with efficiencies comparable to those obtained using ZFNs and TALENs for the same genes. RNA-guided nucleases robustly enabled genome editing at 9 of 11 different sites tested, including two for which TALENs previously failed to induce alterations. These results demonstrate that programmable CRISPR/Cas systems provide a simple, rapid, and highly scalable method for altering genes in vivo, opening the door to using RNAguided nucleases for genome editing in a wide range of organisms. Bacteria and archaea have evolved an elegant adaptive defense mechanism which uses clustered regularly interspaced short palindromic repeats (CRISPR), together with CRISPRassociated (Cas) proteins, to provide acquired resistance to invading viruses and plasmids 1-3 . The type II CRISPR/Cas system relies on uptake of foreign DNA fragments into CRISPR loci 4 and subsequent transcription and processing of these CRISPR repeatspacer arrays into short CRISPR RNAs (crRNAs) 5 , which in turn anneal to a transactivating crRNA (tracrRNA) and direct sequence-specific silencing of foreign nucleic acid by Cas proteins 5-7

    A Novel Universal Primer-Multiplex-PCR Method with Sequencing Gel Electrophoresis Analysis

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    In this study, a novel universal primer-multiplex-PCR (UP-M-PCR) method adding a universal primer (UP) in the multiplex PCR reaction system was described. A universal adapter was designed in the 5′-end of each specific primer pairs which matched with the specific DNA sequences for each template and also used as the universal primer (UP). PCR products were analyzed on sequencing gel electrophoresis (SGE) which had the advantage of exhibiting extraordinary resolution. This method overcame the disadvantages rooted deeply in conventional multiplex PCR such as complex manipulation, lower sensitivity, self-inhibition and amplification disparity resulting from different primers, and it got a high specificity and had a low detection limit of 0.1 ng for single kind of crops when screening the presence of genetically modified (GM) crops in mixture samples. The novel developed multiplex PCR assay with sequencing gel electrophoresis analysis will be useful in many fields, such as verifying the GM status of a sample irrespective of the crop and GM trait and so on
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