Peripheral Blood Mitochondrial DNA Copy Number Is Associated with Prostate Cancer Risk and Tumor Burden

Alterations of mitochondrial DNA (mtDNA) have been associated with the risk of a number of human cancers; however, the relationship between mtDNA copy number in peripheral blood leukocytes (PBLs) and the risk of prostate cancer (PCa) has not been investigated. In a case-control study of 196 PCa patients and 196 age-paired healthy controls in a Chinese Han population, the association between mtDNA copy number in PBLs and PCa risk was evaluated. The relative mtDNA copy number was measured using quantitative real-time PCR; samples from three cases and two controls could not be assayed, leaving 193 cases and 194 controls for analysis. PCa patients had significantly higher mtDNA copy numbers than controls (medians 0.91 and 0.82, respectively; P<0.001). Dichotomized at the median value of mtDNA copy number in the controls, high mtDNA copy number was significantly associated with an increased risk of PCa (adjusted odds ratio  = 1.85, 95% confidence interval: 1.21–2.83). A significant dose-response relationship was observed between mtDNA copy number and risk of PCa in quartile analysis (P_trend = 0.011). Clinicopathological analysis showed that high mtDNA copy numbers in PCa patients were significantly associated with high Gleason score and advanced tumor stage, but not serum prostate-specific antigen level (P = 0.002, 0.012 and 0.544, respectively). These findings of the present study indicate that increased mtDNA copy number in PBLs is significantly associated with an increased risk of PCa and may be a reflection of tumor burden.     

点叶绵枣叶片培养及器官分化的研究

点叶绵枣叶外植体培养于MS 6-BA 1 PPm IBA 0.5 ppm培养基中,一月后不定芽仅从近轴面的叶表面产生。组织学的观察表明,不定芽起源于表皮细胞。     

Regulation of ion channels by integrins

Ion channels are regulated by protein phosphorylation and dephosphorylation of serine, threonine, and tyrosine residues. Evidence for regulation of channels by tyrosine phosphorylation comes primarily from investigations of the effects of growth factors, which act through receptor tyrosine kinases. The purpose of the present work is to summarize evidence for the regulation of ion channels by integrins, through their downstream, nonreceptor tyrosine kinases. We review both direct and indirect evidence for this regulation, with particular emphasis on Ca2+-activated K+ and voltage-gated Ca2+ channels. We then discuss the critical roles that cytoskeletal, focal-adhesion, and channel-associated scaffolding proteins may play in localizing nonreceptor tyrosine kinases to the vicinity of ion channels. We conclude by speculating on the physiological significance of these regulatory pathways.     

Preliminary crystallographic studies of two C-terminally truncated copper-containing nitrite reductases from Achromobacter cycloclastes: changed crystallizing behaviors caused by residue deletion

The C-terminal segment of copper-containing nitrite reductase from Achromobacter cycloclastes (AcNiR) has been found essential for maintaining both the quaternary structure and the enzyme activity of AcNiR. C-terminal despentapeptide AcNiR (NiRc-5) and desundecapeptide AcNiR (NiRc-11) are two important truncated mutants whose activities and stability have been affected by residue deletion. In this study, the two mutants were crystallized using the hanging drop vapor diffusion method. Crystals of NiRc-5 obtained at pH 5.0 and 6.2 both belonged to the P2(1)2(1)2(1) space group with unit cell parameters a=99.0 A, b=117.4 A, c=122.8 A (pH 5.0) and a=98.9A, b=117.7A, c=123.0A (pH 6.2). NiRc-11 was crystallized in two crystal forms: the tetragonal form belonged to the space group P4(1) with a=b=96.0A and c=146.6A; the monoclinic form belonged to the space group P2(1) with a=86.0A, b=110.1A, c=122.7A, and beta=101.9 degrees. The crystallizing behaviors of the two mutants differed from that of the native enzyme. Such change in combination with residue deletion is also discussed here.     

An Apo-14 promoter-driven transgenic zebrafish that marks liver organogenesis

Several transgenic zebrafish lines for liver development studies had been obtained in the first decade of this century, but not any transgenic GFP zebrafish lines that mark the through liver development and organogenesis were reported. In this study, we analyzed expression pattern of endogenous Apo-14 in zebrafish embryogenesis by whole-mount in situ hybridization, and revealed its expression in liver primordium and in the following liver development. Subsequently, we isolated zebrafish Apo-14 promoter of 1763 bp 5'-flanking sequence, and developed an Apo-14 promoter-driven transgenic zebrafish Tg(Apo14: GFP). And, maternal expression and post-fertilization translocation of Apo-14 promoter-driven GFP were observed in the transgenic zebrafish line. Moreover, we traced onset expression of Apo-14 promoter-driven GFP and developmental behavior of the expressed cells in early heterozygous embryos by out-crossing the Tg(Apo14: GFP) male to the wild type female. Significantly, the Apo-14 promoter-driven GFP is initially expressed around YSL beneath the embryo body at 10 hpf when the embryos develop to tail bud prominence. In about 14-somite embryos at 16-17 hpf, a typical "salt-and-pepper" expression pattern is clearly observed in YSL around the yolk sac. Then, a green fluorescence dot begins to appear between the notochord and the yolk sac adjacent to otic vesicle at about 20 hpf, which is later demonstrated to be liver primordium that gives rise to liver. Furthermore, we investigated dynamic progression of liver organogenesis in the Tg(Apo14: GFP) zebrafish, because the Apo-14 promoter-driven GFP is sustainably expressed from hepatoblasts and liver progenitor cells in liver primordium to hepatocytes in the larval and adult liver. Additionally, we observed similar morphology between the liver progenitor cells and the GFP-positive nuclei on the YSL, suggesting that they might originate from the same progenitor cells in early embryos. Overall, the current study provides a transgenic zebrafish line that marks the through liver organogenesis.     

Resolution of N-(2-ethyl-6-methylphenyl) alanine catalyzed by Lipase B from Candida antarctica

A biotransformation process has been developed for the production of (S)-N-(2-ethyl-6-methylphenyl) alanine by enantioselective hydrolysis of racemic methyl ester in the presence of Candida antarctica lipase B (CAL-B). However, the enantioselectivity of CAL-B towards the resolution is not high enough to obtain enantiomerically pure product. In order to improve the enantioselectivity of the enzyme, the effects of surfactants on CAL-B-catalyzed hydrolysis were tested. The results suggest that surfactants can influence the microenvironment of the enzyme, and the addition of Tween-80, in particular, to the reaction medium markedly enhanced the selectivity of CAL-B towards the substrate used, with the enantiomeric ratio (E-value) increasing from 11.3 to 60.1.     

基于转录组数据的密花香薷SSR位点特征分析

利用MISA软件对密花香薷转录组42362条Unigene进行SSR位点搜索,并对其SSR序列结构及分布特征进行了分析。结果表明:(1)密花香薷转录组Unigene序列中共检测到17564个SSR重复序列,分布于11903条Unigene上,出现频率为28.10%,平均每3200 bp出现一个SSR位点。(2)单、二、三核苷酸重复类型为密花香薷转录组SSR位点的主导基序类型,占总SSR位点的97.27%,3种主导基序类型中,单核苷酸所形成基元类型数量最多,共检测到169个基元类型(51.22%),单核苷酸(A/T)n基元类型占明显优势,二核苷酸重复类型(AG/CT)n基元类型占优,分别占总SSR位点的50.60%和12.17%。(3)单核苷酸SSR位点所包含重复次数最多(49),重复次数介于10~66,同一基序类型不同重复次数所形成的SSR位点数量差异较大,随重复次数的增加,SSR位点数呈下降趋势。(4)密花香薷转录组二至六核苷酸基序SSR序列长度集中在12~30 bp区间,共包含有8190个SSR位点,占所统计SSR位点的95.60%,1589(≥20 bp)个SSR序列具有极高的多态性,占所统计SSR位点的18.54%。综合出现频率、分布密度、基元重复次数和长度变异等多个研究结果发现,密花香薷转录组检索到的SSR序列表现出较高的多态性潜能,具有较大的开发价值。该研究为后续密花香薷SSR分子标记引物开发奠定了理论基础。     

Programmed cell death during floral nectary senescence in Ipomoea purpurea

The nectaries of Ipomoea purpurea wilt in the late flowering period. The senescence process of nectaries is frequently associated with cell lysis. In this paper, various techniques were used to investigate whether programmed cell death (PCD) was involved in the senescence process of nectaries in I. purpurea. Ultrastructural studies showed that nectary cells began to undergo structural distortion, chromatin condensation, mitochondrial membrane degradation, and vacuolar-membrane dissolution and rupture after bloom. 4′,6-Diamidino-2-phenylindole (DAPI) and terminal deoxynucleotidyl transferase-mediated 2′-deoxyuridine-5′-triphosphate (dUTP) nick end-labeling (TUNEL) assay showed that nectary cell nuclear DNA began to degrade during the budding stage, and disappeared in the fruiting stage. DNA gel electrophoresis showed that degradation of DNA was random. Together, these results suggest that PCD participate in the senescence of the nectary in I. purpurea. PCD began during the budding period, followed by significant changes in nectary morphology and structure during the flowering period. During the fruiting stage, the PCD process is complete and the nectary degrades.