根据色织物劈花对称原则,将对称配置和简易方程引入劈花方法,对其取值和配置过程进行了探讨,同时对在较宽条纹处劈花,将花色完整循环外的剩余根数纱线的配置进行了分析.结果表明,简易方程引入色织物劈花,能简单确定劈花的起讫点;当方程取值不为整数时,先取整再加以调节;劈花位置处于色织条带相对特宽处,则剩余根数可以直接当做一个条带来配置.

分别采用普通计算公式和经验计算公式对机织工艺设计中的筘号计算数据进行了对比分析.结果表明:用经验公式计算筘号,虽然方法简便,但是结果有误差;入筘数越大,偏差结果越明显,其具体数据只能参考,实际运用时还要加以修正.

茶树中富含茶氨酸、儿茶素和咖啡碱等重要功能成分,具有较高的价值功效,茶树在生命周期中经常遭受逆境胁迫,维生素B6(VB6)在植物体内参与逆境应答,吡哆醛激酶(pyridoxal kinase,PLK)是VB6补救途径中的关键酶.为进一步了解PLK在茶树生物合成中的功能和作用机理,该研究基于茶树基因组数据库,以龙井43为材料,采用逆转录PCR(RT-PCR)的方法从茶树中克隆出CsPLK的基因.结果表明:该基因序列长为1179 bp,编码393个氨基酸;CsPLK蛋白和已知物种中PLK蛋白具有较高的同源性,都是核糖激酶超家族成员;通过构建pET-CsPLK载体进行原核表达,并鉴定出重组蛋白有很强的催化活性;组织表达特异性分析表明,叶中的表达量比茎、根的高,在根中最低;荧光定量PCR表示,低温诱导CsPLK上调表达,干旱诱导CsPLK下调表达,发现该基因在茶树中有明显的逆境应答,推测CsPLK在茶树的生长发育、逆境胁迫发挥重要作用.

Plants are the main producers of vitamin B6 in nature. Among six B6 vitamers, pyridoxal 5′-phosphate is the biologically active form. In plants, de novo biosynthesis of vitamin B6 takes place in cytosol, in which pyridoxal 5′-phosphate is directly synthesized from pentose phosphate, triose phosphate, and glutamine precursors. On the other hand, the major B6 vitamer present in plant-derived foods is usually pyridoxine, either free or glycosylated. Up to now, the formation of pyridoxine in plants is still unclear. In this study, cDNA encoding pyridoxal reductase (PLR) converting pyridoxal into pyridoxine, was cloned from tobacco plants, and analyzed from multi-angle. Our results show that the NtPLR was mainly located in chloroplast, and the highest transcription level was identified from leaves, where the gene transcription was induced by pyridoxal. When tobacco plants were subjected to abiotic stress, the gene transcription showed dynamic changes, with different responses to different stresses. Down-regulation of NtPLR by RNA interference had a big impact on the transcription level of other vitamin B6 metabolic enzymes. Our results suggest that the conversion from pyridoxal to pyridoxine catalyzed by PLR mainly occurs in chloroplast, and that the chloroplast is an important place for vitamin B6 salvage pathway. The results also suggest that there is a linkage mechanism to keep a dynamic balance in the regulation of vitamin B6 metabolism in tobacco plants, and that the dynamic balance of vitamin B6 metabolism may be regulated by genetic networks.

将纳米羟基磷灰石(HAP)溶于一定PH值(氨水调节PH值)的水中,制成HAP质量分数为1％的水分散体系;将聚酯织物浸泡于HAP的水分散体系中12 h,经清洗烘干后,再在纳米二氧化钛(TiO2)质量分数1％的分散体系中浸泡12 h,浸轧后,再在120℃下焙烘2 h;通过对吸附HAP后的聚酯织物的结构和性能进行测试,研究了HAP在不同PH值水中的分散性能,以及HAP对紫外光照射聚酯织物的稳定性及对聚酯本身的保护性能.结果表明:在PH值为12.50时、HAP质量分数为1％的水分散体系中,HAP能均匀致密地分布于聚酯织物表面,并能有效结合;在紫外线强度10000μW/cm2条件下照射2 h后,纳米TiO2光催化剂能促进甲醛和聚酯织物的分解;纳米HAP对聚酯织物光催化分解的保护效果不明显.

研究纳米羟基磷灰石与棉织物结合的方法,根据扫描电镜和抗菌实验结果,分析二者结合方式的形成过程,阐述纳米羟基磷灰石的抗菌机理.结果表明:纳米羟基磷灰石在水中形成的分散体系在棉织物上对3种不同菌种均具有良好的抗菌效果,能达到FZ/T 73023-2006标准的AA抗菌级别.

PNP氧化酶是VB6代谢途径中一个重要的转化酶.该研究以茶树‘龙井43'为材料,采用RT-pCR方法克隆PNP氧化酶基因,以pET22b(+)为载体构建原核表达载体,通过IPTG进行诱导表达并进行功能鉴定;采用荧光定量PCR方法分析茶树不同组织中CsPNPO基因的表达差异以及在低温和干旱胁迫下的表达特征,为进一步解析茶树VB6的生理生化功能奠定基础.结果 表明:(1)茶树CsPNPO编码框长度为1 503 bp,编码501个氨基酸,分子量为48.5 kD,理论等电点5.82,不含信号肽,属于亲水性的非分泌蛋白,定位于叶绿体;氨基酸序列分析结果显示,其有叶绿体转运肽区域、YjeF-N功能域和PNP氧化酶功能域.(2)成功构建pET22b(+)-CsPNPO原核表达载体,并在pH8.5、37℃时测定重组蛋白有较强的PNP氧化酶活性.(3)荧光定量PCR检测结果显示,CsPNPO基因在茶树叶中的表达量最高,其次是茎,根的表达量最低仅为叶的十分之一,表明CsPNPO基因具有组织表达特异性;在低温和干旱条件下CsPNPO基因的表达量下降明显,推测CsPNPO基因可能参与了茶树对低温和干旱的逆境应答.

Pyridoxal 5′-phosphate (PLP), the catalytically active form of vitamin B6, is an important cofactor for many biochemical transformations. Plants are able to synthesize PLP de novo, but they also have a salvage pathway that functions to convert different vitamer forms between each other. Although the salvage enzymes are identified successively from plants, many questions remain unanswered. In the salvage pathway, PLP is synthesized by an ATP-dependent pyridoxal kinase (PLK) and an FMN-dependent pyridoxine 5′-phosphate oxidase (PNPO). In this study, cDNAs encoding PLK and PNPO were cloned from tobacco plants, compared and analyzed, and then the gene expression was down-regulated by RNA interference. Our results show that the NtPLK and NtPNPO contains highly conserved motifs involved in substrate binding or catalysis. NtPLK and NtPNPO are essential enzymes for all tissues of tobacco plants, and NtPNPO is mainly located in chloroplast. The down-regulation of NtPLK and NtPNPO has a greater impact on the transcription level of other vitamin B6 metabolic enzymes. Based on the results, we speculate that, in plants, the de novo synthesized free PLP may be hydrolyzed to PL by phosphatase in cytosol, and then the PL enter into organelles. In organelles, salvage pathway plays its role to produce PLP for maintenance of vitamin B6-mediated processes.

Pyridoxine 5'-phosphate oxidase (PNPO) is a key enzyme for the biosynthesis of pyridoxal 5'-phosphate. Pyridoxal 5'-phosphate is the catalytically active form of vitamin B-6, and acts as a cofactor involved in a high diversity of biochemical reactions. The expression and regulation of PNPO are implicated in numerous physiological and pathological processes. The genomic organization of human PNPO has been reported previously whereas the promoter functional identification is not there yet. In this study, we identified the proximal promoter region of human PNPO gene and analyzed its function. Bioinformatics analysis showed that the transcription start site is at 153 bp upstream of the translation initiation site ATG. Progressive truncation analysis of the 5'-flanking region of PNPO gene demonstrated that two important regulatory regions are located at -996/-852 and -412/+85 bp relative to the transcription start site. From the regulatory regions one USF site, two E2F1 site and multiple Sp1 sites were found. Deletion and mutation experiments indicated that these cis-regulatory elements contribute to the basic promoter activity on different degrees. Downregulation of the transcription factors further indicated that E2F1 plays a dominant role in the transcriptional regulation of PNPO through the binding site at -867/-857, which was confirmed by ChIP assay. Our present study should facilitate further studies on the mechanism regulating the expression of this important gene.

Insect growth and development are primarily controlled by two major hormones, juvenile hormone and molting hormone. 20-Hydroxyecdysone is the most active form of the molting hormone. Although intensive studies have been performed on its biological function and action mechanism, it is still unknown how many genes are directly or indirectly regulated by the molting hormone. Here, we analyzed the genomic transcriptional response to 20-hydroxyecdysone in the fat body of silkworm, by using high-throughput Illumina sequencing technology and bioinformatics tools. In total, 606 differentially expressed genes with 347 up-regulated and 259 down-regulated were detected. The 606 differentially expressed genes were significantly enriched in 118 GO terms, i.e. biological process (68), molecular function (37) and cellular component (13). The KEGG analysis revealed that the significantly enriched pathways were mainly focused on the metabolic processes. The differentially expressed genes were further aligned to the functionally verified sequences of B. mori in the NCBI database, and a total of 43 functional sequences were identified, of which 23 genes were down-regulated and 20 genes were up-regulated. The up-regulated genes mainly relate to metamorphosis, immune response and protein synthesis. RT-qPCR analysis further validated the correctness of the digital gene expression data. Our study gives an overall view of the regulating effect of 20-hydroxyecdysone on the whole-genome transcript expression in the silkworm, provides useful dataset, and will be helpful for the further studies.

Pyridoxal 5'-phosphate (PLP), the catalytically active form of vitamin B-6, is an important cofactor for many biochemical transformations. PLP is also a very reactive molecule, and the most well-established mechanism for maintaining low levels of free PLP is its dephosphorylation by phosphatases. In our previous study, the crude enzyme extract from tobacco leaves rapidly hydrolyzed PLP at a pH optimum of 5.5. Using PLP as a substrate, a novel acid phosphatase was purified from tobacco leaves and characterized. Whether there is a PLP specific phosphatase in plants is still unknown. In this study, a cDNA clone sharing 34.72% homology with human PLP phosphatase sequences was identified from N. tabacum and characterized. The cDNA encodes a polypeptide of 319 amino acid residues, and the recombinant enzyme purified from E. coli exhibited maximum catalytic activity for PLP at pH 7.5. The properties of the purified enzyme, including pH optimum, metal requirement, optimum substrate and inhibitors were similar to those of human PLP phosphatase. Subcellular localization analysis showed that the PLP phosphatase is mainly located in chloroplast. We down-regulated the gene expression with plant RNA interference technology and found that the down-regulation has a greater impact on the transcription of genes encoding vitamin B-6 metabolic enzymes. Our study further suggested that the PLP phosphatase plays an important role for maintaining PLP homeostasis within the chloroplast in plants.

Pyridoxal kinase is a key enzyme for the biosynthesis of pyridoxal 5'-phosphate. Pyridoxal 5'-phosphate is the catalytically active form of vitamin B-6, and acts as a cofactor in > 140 different enzyme reactions. It is still unknown how the kinase synthesis is regulated in the cells, and nothing has been reported about the gene promoter. In the present study, based on the bioinformatics analysis of the 5'-flanking region of the human PDXK gene, we cloned the promoter region by PCR. Through the construction of a series of luciferase expression vectors containing the human PDXK promoter region, we characterized the promoter in terms of its structure and function. The transcription start site is at 198 bp upstream of the ATG translation initiation site. An important regulatory region is located at - 665/ - 433 bp upstream of the transcription start site. The promoter lacks the canonical TATA box, but contains three GC-boxes and one E-box. A deletion and mutation experiment revealed that the transcription factor Sp1 binding site C (- 553/ - 543) is critical in maintaining the robust promoter activity. Knockdown of Sp1 by RNA interference and chromatin immunoprecipitation analysis further proved that the Sp1 is involved in the regulation of the PDXK gene expression.

Vitamin B6(VB6), essential for plant growth and development and involved in more than 100 biologi-cal processes, utilizes pyridoxal reductase (PLR) as the key enzyme in the VB6 salvage pathway, thereby cat-alyzing pyridoxal (PL) to generate pyridoxine (PN). Since studies on PLR of plant VB6 are quite limited, PLR genes were cloned and characterized to improve understanding of VB6 biosynthesis in plants. Several NtPLR1 gene fragments were found in Nicotiana tabacum through a homologous blast with Arabidopsis AtPLR1. Full length was obtained using rapid amplification of cDNA ends (RACE). Real-time quantitative polymerase chain reaction (PCR) and high performance liquid chromatography (HPLC) analysis were conducted; NtPLR1 ex-pression by ultraviolet, oxidation, exogenous PL, and NaCl treatments were compared to a control; and prokary otic expression of NtPLR1 was accomplished. Results of RACE showed that full length cDNA of NtPLR1 was 1370 bp, which encoded 369 amino acid residues with a protein molecular weight of about 41 kDa and a the-oretical isoelectric point of 9.42. Real-time quantitative PCR analysis revealed that an exogenous PL treatment induced NtPLR1 expression with highest expression at 4 d. The HPLC analysis showed that PL content signifi-cantly decreased (P<0.05); whereas, PN content significantly increased (P<0.05) during an exogenous PL treatment. NtPLR1 was expressed in roots, stems, and leaves with leaves having the highest (P<0.05) expres-sion level. Also, ultraviolet, oxidation, and NaCl treatments, compared to a control, significantly induced (P<0.05) NtPLR1 expression. Furthermore, prokaryotic expression of NtPLR1 in vector pET32a successfully re-vealed the recombinant protein at the expected size. This study reported the NtPLR1 gene of N. tabacum for the first time, finding that it catalyzed PL to form PN in tobacco as found in yeast, and it may be induced in response to ultraviolet, oxidation, and NaCl stress; thus, the NtPLR1 gene can be an important reference for further plant PLR gene functional characterization and regulation as well as VB6 biosynthesis. [Ch, 8 fig. 1 tab. 25 ref.]

Vitamin B6 comprises six interconvertible pyridine compounds, among which pyridoxal 5′-phosphate (PLP) is a coenzyme for over 140 enzymes. PLP is also a very reactive aldehyde. The most well established mechanism for maintaining low levels of free PLP is its dephosphorylation by phosphatases. A human PLP-specific phosphatase has been identified and characterized. However, very little is known about the phosphatase in other living organisms. In this study, a cDNA clone of putative PLP phosphatase was identified from B. mori and characterized. The cDNA encodes a polypeptide of 343 amino acid residues, and the recombinant enzyme purified from E. coli exhibited properties similar to that of human PLP phosphatase. B. mori has a single copy of the PLPP gene, which is located on 11th chromosome, spans a 5.7kb region and contains five exons and four introns. PLP phosphatase transcript was detected in every larva tissue except hemolymph, and was most highly represented in Malpighian tube. We further down-regulated the gene expression of the PLP phosphatase in 5th instar larvae with the RNA interference. However, no significant changes in the gene expression of PLP biosynthetic enzymes and composition of B6 vitamers were detected as compared with the control.

Vitamin B6 includes 6 pyridine derivatives, among which pyridoxal 5'-phosphate is a coenzyme for over 140 enzymes. Animals acquire their vitamin B6 from food. Through a salvage pathway, pyridoxal 5'-phosphate is synthesized from pyridoxal, pyridoxine or pyridoxamine, in a series of reactions catalyzed by pyridoxal kinase and pyridoxine 5'-phosphate oxidase. The regulation of pyridoxal 5'-phospahte biosynthesis and pyridoxal 5'-phospahte homeostasis are at the center of study for vitamin B6 nutrition. How pyridoxal 5'-phosphate biosynthesis is regulated by hormones has not been reported so far. Our previous studies have shown that pyridoxal 5'-phosphate level in silkworm larva displays cyclic developmental changes. In the current study, effects of exogenous juvenile hormone and molting hormone on the transcription level of genes coding for the enzymes involved in the biosynthesis of pyridoxal 5'-phospahte were examined. Results show that pyridoxal kinase and pyridoxine 5'-phosphate oxidase are regulated at the transcription level by development and are responsive to hormones. Molting hormone stimulates the expression of genes coding for pyridoxal kinase and pyridoxine 5'-phosphate oxidase, and juvenile hormone appears to work against molting hormone. Whether pyridoxal 5'-phosphate biosynthesis is regulated by hormones in general is an important issue for further studies.

Vitamin B6 comprises six interconvertible pyridine compounds (vitamers), among which pyridoxal 5′-phosphate is a coenzyme involved in a high diversity of biochemical reactions. Humans and animals obtain B6 vitamers from diet, and synthesize pyridoxal 5′-phosphate by pyridoxal kinase and pyridoxine 5′-phosphate oxidase. Currently, little is known on how pyridoxal 5′-phosphate biosynthesis is regulated, and pyridoxal 5′-phosphate is supplied to meet their requirement in terms of cofactor. Bombyx mori is a large silk-secreting insect, in which protein metabolism is most active, and the vitamin B6 demand is high. In this study, we successfully down-regulated the gene expression of pyridoxal kinase and pyridoxine 5′-phosphate oxidase by body cavity injection of synthesized double-stranded small interfering RNA to 5th instar larvae of Bombyx mori, and analyzed the gene transcription levels of pyridoxal 5′-phosphate dependent enzymes, phosphoserine aminotransferase and glutamic-oxaloacetic transaminase. Results show that the gene expression of pyridoxal kinase and pyridoxine 5′-phosphate oxidase has a greater impact on the gene transcription of enzymes using pyridoxal 5′-phosphate as a cofactor in Bombyx mori. Our study suggests that pyridoxal 5′-phosphate biosynthesis and dynamic balance may be regulated by genetic networks.

In six different vitamin B_6 forms, pyridoxal 5′-phosphate(PLP) is a catalytically active form of VB_6 It acts as cofactor in more than 140 different enzyme reactions. Animals obtain PLP form VB_6 from diet and recycled it in a pathway, which essentially involves two ubiquitous enzymes: pyridoxal kinase and pyridoxine5′-phosphate oxidase. Proper functioning of PLP-dependent enzymes and thus the optimal health of the human body are dependent upon an adequate level of PLP in the cell. However, the mechanism and regulation of PLP homeostasis, and the mechanism of addition of PLP to the apo-B_6-enzymes are poorly understood and represent a very challenging research field. This article summarizes the current knowledge on the two enzymes involved in the PLP salvage pathway.

[目的] 研究家蚕Bombyx mori经蜕皮激素(20-hydroxyecdysone,20-E)和保幼激素类似物(juvenile hormone analogue,JHA)处理后引起吡哆醛激酶(pyridoxal kinase,PLK)和磷酸吡哆醇氧化酶(pyridoxine-5'-phosphateoxidase,PNPO)的转录水平变化,为进一步研究激素对蚕体营养代谢等工作奠定基础.[方法]以20-E和JHA分别喂食不同发育时期(5龄第1,3和5天)的家蚕幼虫,以喂食蒸馏水的家蚕为对照,采用实时荧光定量PCR(real-time quantitative PCR)方法在处理后24和48 h对各组幼虫后部丝腺中PLP合成酶PLK和PNPO的转录水平进行分析.[结果]5龄第1天幼虫经20-E处理24和48 h后,PLK和PNPO的转录水平出现上调且与对照的差异达到极显著(P＜0.01);5龄第3天幼虫经20-E处理,PLK的转录水平在48 h出现下调且与对照的差异达到显著(P＜0.05),PNPO的转录水平在24和48 h均出现上调且与对照的差异达到极显著(P＜0.01);5龄第5天幼虫经20-E处理后PLK和PNPO的转录水平无变化.5龄第1天幼虫经JHA处理后PLK和PNPO的转录水平未受到影响;5龄第3天幼虫经JHA处理后,PLK的转录水平在48 h出现显著下调且与对照的差异达到显著(P＜0.05),PNPO的转录水平在24和48 h后均出现显著下调且与对照的差异达到极显著(P＜0.05);5龄第5天幼虫经JHA处理24和48 h后,PLK和PNPO的转录水平出现下调且与对照的差异达到极显著(P＜0.01).[结论]20-E和JHA显著影响家蚕5龄幼虫PLK和PNPO的转录水平,20-E提高5龄前期家蚕PLK和PNPO的转录水平,JHA降低5龄后期它们的转录水平,为深入研究激素对VB6的调控奠定基础.