外源氯对番茄幼苗生长及养分吸收、利用的影响

 研究了不同水平外源氯处理对番茄(Lycopersicon esculentum L. ) 干物质积累、叶绿素含量、Cl^- 、NO₃^- 、氮、磷、钾、钙和镁含量的影响。结果表明: 一定范围( 6.25～100 nmol·L ^{- 1} ) 的外源氯处理, 不降低番茄生物量甚至促进生物量, 并可明显提高番茄幼苗对钾、镁、磷的吸收和氮素利用效率, 而200、300 mmol·L ^{- 1} Cl^- 处理的幼苗干物质积累极显著下降。     

Chloride channels of platelets

Chloride channels distribute widely in the body, and participate in many physiological actions and regulatory processes. Based on their physiological roles and molecular structures, six kinds of chloride channels have been identified: (1) The chloride channels family; (2) Cystic fibrosis transmembrane conductance regulator; (3) Swelling-activated chloride channels; (4) Calcium-activated chloride channels; (5) The p64 (CLIC) gene family; (6) γ-aminobutyric acid and glycine receptors. The chloride channels do exist in platelets, and their appearances are dependent on the presence of intracellular calcium. Blocking agents of chloride channels inhibit the thrombin-activated platelet aggregation and the elevation of the intracellular calcium concentration in a dose-dependent manner. It is suggested that chloride channels play a role in the activation of platelets. In addition, chloride channels act on both the cell volume regulation and the intracellular pH regulation in platelets.     

生态因素和栽培农艺措施对烟草钾和氯含量影响研究进展

钾、氯是烟草生长发育的必需营养元素,也是衡量烟叶内在品质的重要指标,钾氯比值常被用作评价烟叶品质、燃烧性的基础,因此合理调控烟叶钾、氯含量,对改善烟叶品质、提高烟叶质量、提升烟叶工业可用性具有重要意义。探讨了生态因素、栽培农艺措施对烟草钾、氯含量影响的研究进展。     

沙质农田表层土壤水分扩散率测定及氯化钴试纸的应用研究

非饱和土壤水分扩散率是研究土壤水分运动规律必不可少的基本参数之一。本文应用水平土柱入渗法测定了科尔沁沙地沙质农田表层土壤的非饱和水分扩散率,并对氯化钴试纸在测定水分扩散率中的应用作了初步尝试和研究。主要结论如下：沙质农田表层土壤湿润锋迁移速率随着入渗距离的增大而减小,呈幂函数关系;波尔兹曼参数与土壤含水量呈直线关系;土壤水分扩散率与土壤含水量之间的关系,符合经验公式并呈指数函数变化。在应用水平土柱法测定非饱和土壤水分扩散率的过程中,氯化钴试纸法可以用于测定湿润锋的位置,特别是在高土壤含水量时,相比目视法而言更能显示其优势,在一定程度上可以提高测定结果的可靠性。     

La对UV - B辐射下大豆幼苗 NRA和可溶性蛋白的影响

在温室模拟增强紫外辐射UV - B (280～320nm)环境下,研究镧(La)对UV - B胁迫下大豆幼苗叶片硝 酸还原酶活性(Nitrate reductase activity,NRA) 、可溶性蛋白、淀粉和可溶性糖含量的影响。结果显示,高低两个紫 外强度剂量下,叶片NRA较对照组都有显著下降,处理5d后降幅分别达到40. 9%和42. 0%;而经过适宜浓度 LaCl3 (20mg/L)预处理后,降幅较UV - B单独处理组均有明显升高,分别为39. 2%和38. 9%。蛋白质、淀粉和可溶 性糖含量变化与NRA相似,但是紫外辐射处理组蛋白含量变化较对照组呈现先升高后下降趋势。结果表明适宜 浓度的La3 +能够促进NRA以及UV - B胁迫下NRA活性的提高,缓解UV - B胁迫对植物的伤害。     

Evaluation of the extent of the oxidation reaction during chlorine bleaching of pulp

A modified method was developed to evaluate how much chlorine is consumed by the oxidation reaction during the chlorine bleaching process. This evaluation is, in principle, based on the sum of chloride produced during the chlorination stage (C-stage) and produced during alkali treatment of both the C-stage effluent and the chlorinated pulp. Results obtained by this method proved that about 50%–75% of chlorine was consumed by the oxidation reaction during chlorine bleaching, depending on the reaction condition of chlorination. Even under a reaction condition that is not favorable to an oxidation reaction (low pH), approximately three electrons were abstracted from one lignin structural unit by chlorine bleaching. This result provides additional evidence for our recent observation that lignin is extensively oxidized during chlorine bleaching even when pure chlorine without any chlorine dioxide substitution was used.Part of this paper was presented at the 40th Lignin Symposium. Tsukuba, Japan, October 12, 1995     

免疫活性肽促进雏鸡红细胞免疫应答的研究

将7日龄试验用鸡随机分成4组,A组每只鸡口服0.05 ml免疫活性肽溶液,B组每只鸡口服盐酸左旋咪唑15 mg/kg体重,C组口服0.05 ml生理盐水,D组为空白对照,于处理后7天、14天时采用红细胞免疫指标检测方法,并求其平均值。试验结果表明,14日龄和21日龄时A组的红细胞-C3b受体花环率极显著高于对照组(P<0.01),而红细胞-IC受体花环率显著低于对照组(P<0.05)。B组与对照组的红细胞-C3b受体花环率与红细胞-IC受体花环率差异显著(P<0.05)。A组与B组之间差异也达极显著水平(P<0.01)。表明免疫活性肽与盐酸左旋咪唑均具有红细胞免疫增强作用,且免疫活性肽显著优于盐酸左旋咪唑。     

Effect of CLCN2 antisense oligonucleotide on U251 cells injury by cisplatin

AIM: To investigate the effect of chloride channel CLCN2 antisense oligonucleotide on the cell injury of malignant U251 glioma cells induced by cisplatin (DDP). METHODS: The experiment was divided into 4 groups: control group (nonsense oligonucleotide), CLCN2 antisense oligonucleotide group, DDP group (DDP＋nonsense oligonucleotide), DDP＋CLCN2 antisense oligonucleotide group. The viability of U251 cells was measured by MTT assay, CLCN2 mRNA level was determined by RT-PCR, cell apoptosis was measured by TUNEL assay. RESULTS: Compared to the control group, the cell viability, CLCN2 and cyclinD1 mRNA decreased in CLCN2 antisense oligonucleotide group, DDP treated group and CLCN2 antisense oligonucleotide with DDP treated group, cells apoptosis increased. Compared to DDP group, the cell viability (P<0.05) and CLCN2 mRNA decreased in CLCN2 antisense oligonucleotide with DDP treated group, and cells apoptosis increased (P<0.01). Compared to CLCN2 antisense oligonucleotide group, CLCN2 mRNA significantly decreased (P<0.01) in CLCN2 antisense oligonucleotide with DDP treated group. CONCLUSION: CLCN2 antisense oligonucleotide inhibits the expression of CLCN2 mRNA in U251 cells. Inhibition of CLCN2 mRNA facilitates the cell injury of U251 cells induced by DDP. The decrease in CLCN2 mRNA is involved in the mechanism of cell injury by DDP.     

Role of Cl- in regulatory volume decrease of nasopharyngeal carcinoma cells

AIM:To clarify the role of Cl^- in regulatory volume decrease (RVD) of nasopharyngeal carcinoma cells (CNE-2Z).METHODS:Analysis of living cell images was used to detect the volume changes following exposure to hypotonic solution. Iron replacement and block of iron channels were also applied in the present study. RESULTS:Extracelluar hypotonic treatment made the cells swell and induced RVD. The RVD was correlated positively to the swelling in the range of 160-230 mOsmol/L. Substitution of gluconate for Cl^- in perfusing solutions markedly increased RVD. Depletion of cellular Cl^- abolished, and chloride channel blockers inhibited RVD. CONCLUSION:Cl^- is the key iron to establish the RVD in CNE-2Z cells. Activation of Cl^- channels and Cl^- efflux are the major mechanisms of RVD.     

Effects of tamoxifen on volume-activated Cl- currents of nasopharyngeal carcinoma cells at different stages of the cell cycle

AIM:To investigate the inhibitory effects of Cl- channel blocker, tamoxifen, on volume-activated Cl- currents of nasopharyngeal carcinoma cells (CNE-2Z cells) in G₁ and S phases. METHODS:Highly synchronous cells in G₁ phase and S phase were obtained by the serum starvation and the double-block techniques. The whole-cell patch clamp technique was used to observe the effects of tamoxifen on volume-activated Cl- currents and to analyze the anion permeability of volume-activated Cl- channels. RESULTS:47% hypotonic stimulation activated a Cl- current in the nasopharngeal carcinoma cells at the cell cycle stage G₁ phase and S phase. Tamoxifen at concentration of 10 to 30 μmol/L completely inhibited the current. However, the time needed to completely inhibit the current was dose-dependent and was different between G₁ phase and S phase. The time needed to completely inhibit the current was shorter in G₁ cells than that in S phase cells. The anion permeability sequence of the volume-activated Cl- channel was I->Cl->gluconate in both G₁ phase and S phase cells. The permeability of G₁ phase cells to I- was higher than that in S phase cells, but to gluconate was lower than that in S phase cells. CONCLUSIONS:The density of the volume-activated Cl- current, the anion permeability of the channel and the sensitivity of the current to tamoxifen were different between the CNE-2Z cells in G₁ phase and those in S phase. The results suggest that the expression of tamoxifen-sensitive, volume-activated chloride channels is differentiated at different stages of the cell cycle.