Relationship between chemokine (C–X–C motif) ligand 12 gene variant (rs1746048) and coronary heart disease: Case–control study and meta-analysis

The goal of our study is to evaluate the contribution of CXCL12 rs1746048 (hg19, chr10:44775574) to the risk of CHD in Han Chinese, and to summarize its role in CHD through meta-analysis of existing studies among various ethnic groups. Significant association is observed between rs1746048-C and an increased risk of CHD in Han Chinese (χ² = 5.41, df = 1, P = 0.02). Post hoc analysis reveals an even stronger association of rs1746048 with the risk of CHD for subjects aged 65 years or older (genotype: χ² = 8.39, df = 2, P = 0.015; allele: χ2 = 9.13, df = 1, P = 0.003, odd ratio (OR) = 1.91, 95% confidential interval (CI) = 1.25–2.91). A break down analysis by gender shows that rs1746048 is likely a CHD risk factor under the recessive model in males (CC + CT versus TT: P = 0.05, χ² = 3.59, df = 1, OR = 1.72, 95% CI = 1.00–3.04). In addition, a meta-analysis of ten studies among over 107,000 individuals confirms that rs1746048 is a risk factor of CHD (P < 0.0001, OR = 1.12, 95% CI = 1.09–1.15) and this agrees with the findings of our case–control study in Han Chinese.     

Maize DNA polymerase alpha is phosphorylated by a PCNA-associated cyclin/Cdk complex: effect of benzyladenine

The activity of maize DNA polymerases 1 and 2 (delta and alpha-type enzymes, respectively) is stimulated during germination if embryo axes are imbibed in the presence of benzyladenine. In vivo, DNA pol 2 is a phosphorotein that appears to be maximally phosphorylated previous to the S phase start time (by 12 h of germination, Coello and Vázquez-Ramos 1995a). We find that, in vitro, a PCNA-associated cyclin/kinase activity isolated from maize axes acquires an increasing capacity to phosphorylate DNA pol 2 as germination advances; moreover, the PCNA-associated kinase isolated from BA-treated maize axes germinated at 3 h phosphorylates DNA pol 2 at the same level observed in samples of axes germinated for 13 h in the absence of exogenous BA. PCNA-associated kinase activity from BA-treated axes germinated at 13 h maximal using DNA pol 2 as substrate. However, there is no modification in DNA polymerase activity as a consequence of protein phosphorylation. Results are discussed in terms of their significance for cell cycle regulation during seed germination.     

Application of C stable isotope labeling liquid chromatography–multiple reaction monitoring–tandem mass spectrometry method for determining intact absorption of bioactive dipeptides in rats

The liquid chromatography–multiple reaction monitoring–tandem mass spectrometry (LC–MRM–MS/MS) method using ¹³C stable isotope-labeled dipeptides was newly developed to simultaneously determine the absorption of three antihypertensive peptides (Val-Tyr, Met-Tyr, and Leu-Tyr) into blood of spontaneously hypertensive rats in one run-in assay. After extracting ¹³C-labeled peptides in blood sample with a C₁₈ cartridge, the extract was applied to a ¹³C monoisotopic transition LC–MRM–MS/MS system with d-Val-Tyr included as internal standard. An excellent separation of each dipeptide in LC was achieved at the elution condition of 5–100% methanol in 0.1% formic acid at a flow rate of 0.25 ml/min. The ¹³C-labeled peptides ionized by electron spray were detected in the positive ion mode within 15 min. The established method showed high reproducibility with less than 10% coefficient of variation as well as high accuracy of more than 85%. After the administration of a mixture containing the three ¹³C-labeled dipeptides to rats at each dose of 30 mg/kg, we could successfully determine the intact absorption of each ¹³C-labeled peptide with the maximal absorption amount of 1.1 ng/ml plasma for Val-Tyr by the proposed LC–MRM–MS/MS method.     

维生素C和E合用对中华鳖幼鳖非特异性免疫功能的影响

本研究旨在探讨维生素C和E合用对中华鳖幼鳖非特异性免疫功能的影响。实验设 5组 ,5组饵料中维生素C和E的添加量依次为 0和 0mg/kg(对照组 ) ;2 5 0和 5 0mg/kg(实验Ⅰ组 ) ;2 5 0 0和 2 5 0mg/kg(实验Ⅱ组 ) ;2 5 0和2 5 0mg/kg(实验Ⅲ组 ) ;2 5 0 0和 2 5 0mg/kg(实验Ⅳ组 )。喂食 4周 ,取其血液 ,测定中华鳖血细胞的吞噬率、血清溶菌活力、杀菌活力、补体C3和C4。结果表明 ,实验Ⅱ—Ⅳ组 ,血细胞吞噬率和血清杀菌活力明显高于对照组 ,实验Ⅳ组明显高于其他 4组 ,并且维生素C和E之间有明显的协同作用。血清溶菌活力和补体C3的含量 ,在实验Ⅰ—Ⅳ组明显高于对照组 ,实验Ⅳ组明显高于其他 4组。补体C4在实验Ⅰ—Ⅳ组明显高于对照组 ,但实验Ⅰ—Ⅳ组间没有明显差别 ,维生素C和E间也没有协同作用。     

黄土高原刺槐人工林幼林生态系统碳吸存

为了解黄土高原生态林的固碳作用,以刺槐人工林幼林（8年生）和对照荒地为研究对象,比较了两种土地利用方式下,土壤、凋落物和植物各部分的有机碳密度(OCD)和生态系统碳吸存的变化.结果表明:刺槐人工林林地土壤OCD比荒地减少0.26 kg·m^-2,其中0～10 cm层土壤OCD显著提高,10～30 cm土层降低,而在30～80 cm层土壤中则变化不明显.与荒地相比,刺槐人工林林地凋落物、植物根系和植物地上部分的OCD分别增加了121.1%、202.0%和656.7%,每年总有机碳吸存率增加3.3%,说明黄土高原营造刺槐人工林具有明显的碳吸存效应.     

穗花杉染色体的研究

穗花杉为国家三级重点保护的珍稀濒危植物,雌雄异株。根尖细胞染色体分析表明：雌株和雄株的染色体数目为２ｎ＝４０,其中第１对和第２对为中部着丝粒染色体,第３－２０对为端部着丝粒染色体。核型为２ｎ＝４０＝４ｍ＋３６Ｔ。雌雄株除第２对的长度稍有差异外,其余各对的相对长度和臂比都较近似,可能尚无性染色体分化。Ｇｉｅｍｓａ Ｃ带显示,间期核有３个较大的染色中心,最长的３条染色体的中央缢痕有深染色带纹,可能是着     

Photosynthetic pathway influences xylem structure and function in Flaveria (Asteraceae)

Higher water use efficiency (WUE) in C(4) plants may allow for greater xylem safety because transpiration rates are reduced. To evaluate this hypothesis, stem hydraulics and anatomy were compared in 16 C(3), C(3)-C(4) intermediate, C(4)-like and C(4) species in the genus Flaveria. The C(3) species had the highest leaf-specific conductivity (K(L)) compared with intermediate and C(4) species, with the perennial C(4) and C(4)-like species having the lowest K(L) values. Xylem-specific conductivity (K(S)) was generally highest in the C(3) species and lower in intermediate and C(4) species. Xylem vessels were shorter, narrower and more frequent in C(3)-C(4) intermediate, C(4)-like and C(4) species compared with C(3) species. WUE values were approximately double in the C(4)-like and C(4) species relative to the C(3)-C(4) and C(3) species. C(4)-like photosynthesis arose independently at least twice in Flaveria, and the trends in WUE and K(L) were consistent in both lineages. These correlated changes in WUE and K(L) indicate WUE increase promoted K(L) decline during C(4) evolution; however, any involvement of WUE comes late in the evolutionary sequence. C(3)-C(4) species exhibited reduced K(L) but little change in WUE compared to C(3) species, indicating that some reduction in hydraulic efficiency preceded increases in WUE.     

Plagiochilines C,D, E and F,four novel secoaromadendrane-type sesquiterpene hemiacetals from Plagiochila asplenioides and Plagiochila semidecurrens

Four novel secoaromadendrane-type sesquiterpene hemiacetals, plagiochilines C, D, E and F, together with the previously known (?)-bicyclogermacrene, have been isolated from the liverwort, Plagiochila asplenioides and their structures have been spectroscopically elucidated. From Plagiochila semidecurrens plagiochilines A and C have been obtained along with (?)-bicyclogermacrene and its related sesquiterpene hydrocarbons.     

miR-27a is a negative regulator of adipocyte differentiation via suppressing PPARγ expression

microRNAs (miRNAs) are non-coding small RNAs regulating gene expression, cell growth, and differentiation. Although several miRNAs have been implicated in cell growth and differentiation, it is barely understood their roles in adipocyte differentiation. In the present study, we reveal that miR-27a is involved in adipocyte differentiation by binding to the PPARγ 3′-UTR whose sequence motifs are highly conserved in mammals. During adipogenesis, the expression level of miR-27a was inversely correlated with that of adipogenic marker genes such as PPARγ and adiponectin. In white adipose tissue, miR-27a was more abundantly expressed in stromal vascular cell fraction than in mature adipocyte fraction. Ectopic expression of miR-27a in 3T3-L1 pre-adipocytes repressed adipocyte differentiation by reducing PPARγ expression. Interestingly, the level of miR-27a in mature adipocyte fraction of obese mice was down-regulated than that of lean mice. Together, these results suggest that miR-27a would suppress adipocyte differentiation through targeting PPARγ and thereby down-regulation of miR-27a might be associated with adipose tissue dysregulation in obesity.     

Protein Kinase C of Sympathetic Neuronal Membrane Is Activated by Phorbol Ester-Correlation Between Transmitter Release, 45Ca2+ Uptake, and the Enzyme Activity

The effects of phorbol esters [phorbol 12,13-dibutyrate (PDB), 12-O-tetradecanoylphorbol 13-acetate (TPA), and phorbol 13-acetate] were investigated on the release of [3H]norepinephrine, 45Ca2+ accumulation, and protein kinase C activity in cultured sympathetic neurons of the chick embryo. Sympathetic neurons derived from 10-day-old chick embryo were cultured in serum-free medium supplemented with insulin, transferrin, and nerve growth factor. After 3 days, neurons were loaded with [3H]-norepinephrine and the release of [3H]norepinephrine was determined before and after electrical stimulation. Stimulation at 1 Hz for 15 s increased the release of [3H]-norepinephrine over the nonstimulation period. Stimulation-evoked release gradually declined with time during subsequent stimulation periods. Incubation of neurons in Ca2+-free Krebs solution containing 1 mM EGTA completely blocked stimulation-evoked release of [3H]-norepinephrine. Stimulation-evoked release of [3H]-norepinephrine was markedly facilitated by 3 and 10 nM PDB or TPA. The spontaneous release was also enhanced by PDB and TPA. The net accumulation of 45Ca2+ during stimulation of sympathetic neurons was increased by two- to fourfold in the presence of PDB or TPA. PDB at 1-100 nM produced a concentration-dependent increase in the activation of protein kinase C. PDB at 30 nM increased the activity of protein kinase C of the particulate fraction from 0.09 to 0.58 pmol/min/mg protein. There was no significant change in protein kinase C activity of the cytosolic fraction (0.14 pmol/min/mg versus 0.13 pmol/min/mg protein). The ratio of the particulate to cytosolic protein kinase C increased from a control value of 0.62 to 4.39 after treatment with 30 nM PDB. TPA (10 and 30 nM) also increased protein kinase C activity of the particulate fraction by six- to eightfold. Phorbol 13-acetate had no effect on protein kinase C activity, [3H]norepinephrine release, and 45Ca2+ accumulation. These results provide direct evidence that activation of protein kinase C enhances Ca2+ accumulation, which in turn leads to the facilitation of transmitter release in sympathetic neurons.