NaCl浓度对金黄色葡萄球菌核酸酶酸变性态结构的影响

金黄色葡萄球菌核酸酶类似物(SNaseR)的酸变性态(U_A)在较高NaCl浓度下可转变为另一种稳定的酸变性态(A态),即U_A→A.CD谱测定结果表明A态结构中具有大量二级结构.体积排除色谱测定表明A态具有接近于天然态的堆积密度.A态可与疏水性荧光探针ANS结合.A态的这些特征表明其结构类似于熔球态.NaCl和HCl诱寻的U_A→A构象转变曲线相互重合,表明U_A→A转变是由C1^-与A态酶分子结合所引起的.C1^-结合到A态酶分子上稳定了该酶的α螺旋结构.盐酸胍可使A态发生变性.

Dynamic Changes of Nitrate Reductase Activity within 24 Hours

[Objective] The research aimed to study the circadian rhythm of nitrate re- ductase activity （NRA） in plant. [Method] The wheat plants at heading stage were used as the materials for the measurement of dynamic changes of nitrate reductase activity （NRA） within 24 h under the conditions of constant high temperature. [Resulti The fluctuation of NRA in wheat changed greatly from 20：00 pm to 11：00 am. The enzyme activity remained constant, but at 14：00 the enzyme activity was the high- est, higher than all the other time points except the enzyme activity measured at11：00. The enzyme activity was the lowest of 17：00, which was lower than all the other time points except the enzyme activity measured at 2：00. [Conclusion] There were autonomous rhythm changes of NRA in wheat in a certain degree.

Association of myostatin Variants with Growth Traits of Zhikong Scallop(Chlamys farreri)

Scallop is a popular sea food and an important aquaculture shellfish.Identification of genes and genetic variants relating to scallop growth could benefit high-yielding scallop breeding.Myostatin(MSTN) is a conservative regulator of muscle growth,and has become one of the most important target genes for genetic improvement of the production of farmed animals.In this study,four single nucleotide polymorphisms(SNPs) were identified in the 5' flanking region of MSTN gene(Cf MSTN) in Zhikong scallop(Chlamys farreri).The association of these SNPs with scallop growth traits,including shell length,shell height,body weight and striated muscle weight was analyzed.The SNP g-1162G>T was found to associate with shell length,shell height,and striated muscle weight.The TT type scallops showed significantly higher trait values than those of GT type,and the GG type individuals exhibited median values.On the contrary,significantly more Cf MSTN transcripts were detected in the striated muscle of GT type scallops than in those of TT and GG type ones.Our results suggested that Cf MSTN might regulate the scallop muscle growth negatively,and SNP g-1162G>T can be used as a candidate marker for the selective breeding of high-yielding scallop.

Genetic polymorphisms in non-alcoholic fatty liver disease:Clues to pathogenesis and disease progression

The spectrum of non-alcoholic fatty liver disease(NAFLD) ranges from simple steatosis through steatohepatitis to advanced f ibrosis and cirrhosis.Although the reason why only a minority of patients develop progressive forms of disease still remains largely unclear,recent research has identified genetic factors as a possible basis for this variation in disease presentation.Most of the studies have been focused on f inding associations between advanced disease forms and selected single nucleotide polymorphisms in genes encoding various proteins involved in disease pathogenesis.Although there are many limitations regarding the study design and interpretation of published data,further carefully planned studies together with implementation of new genetic technologies will likely bring new insights into disease pathogenesis and potential benefits to the management of patients with NAFLD.

TLR4 -2242 T→C variant increases transcriptional activity of its promoter

Objective:To investigate the effects of -2242,-1892 and -1837 single nucleotide polymorphisms(SNPs) on toll-like receptor 4(TLR4) promoter activity.Methods:Polymerase chain reaction(PCR) and site direct mutation technology were used to construct TLR4 basic promoter and -2242C,-1892A and -1837G mutate promoter plasmids.Dual-Luciferase Reporter assay system was used to detect the activity of constructed promoter following human embryonic kidney(HEK) 293 cells were transiently cotransfected with the constructed plasmids and the control plasmid pRL-CMV.Results:In HEK293 cells,the activity of -2242C mutate promoter was higher than -2242T promoter,and there was no significant difference when both -1892A and -1837G mutate promoter compared with -1892G and -1837A promoter,respectively.Conclusion:It is implied that -2242T→C base variation can enhance the activity of TLR4 promoter,while -1892 and -1837 SNPs have no effect on TLR4 promoter activity.

De novo identification and quantification of single amino-acid variants in human brain

The detection of single amino-acid variants （SAVs） usually depends on single-nucleotide polymorphisms （SNPs） database. Here, we describe a novel method that discovers SAVs at proteome level independent of SNPs data. Using mass spectrometry-based de novo sequencing algorithm, peptide-candidates are identified and compared with theoretical protein database to generate SAVs under pairing strategy, which is followed by database re-searching to control false discovery rate. in human brain tissues, we can confidently identify known and novel protein variants with diverse origins. Combined with DNA/RNA sequencing, we verify SAVs derived from DNA mutations, RNA alternative splicing, and unknown post-transcriptional mechanisms. Furthermore, quantitative analysis in human brain tissues reveals several tissue-specific differential expressions of SAVs. This approach provides a novel access to high-throughput detection of protein variants, which may offer the potential for clinical biomarker discovery and mechanistic research.