利用17个微卫星标记分析鳙鱼的遗传多样性

选用实验室克隆的17个鳙鱼微卫星分子标记分析四川泸州和江西鄱阳湖的两个种群鳙鱼的遗传多样性及种质特性,计算和统计了杂合度、多态信息含量(PIC)、有效等位基因数、等位基因频率、遗传距离、遗传相似系数、Hardy-Weinberg平衡偏离指数等方面内容。结果表明:选择使用17个微卫星标记,其中有4个为单态标记,13个为多态标记。江西和四川鳙鱼群体每个微卫星位点的平均等位基因数分别为3.325及3.882,平均有效等位基因数分别为3.531及2.676,多态位点百分率分别为82.4及70.5,17个微卫星标记

Hg~(2+)与POD复合处理对小麦萌发及幼苗生长的影响

通过水培实验研究了0、10、20、50、70和100 mg.L-1 Hg2+和65 U.mL-1的过氧化物酶(POD)混合浸种对小麦(Triticum aestivum L.)萌发及幼苗生长过程中的10个形态和生理生化指标的影响。结果表明:施加外源POD可明显提高种子发芽率、植株日均增重和幼苗叶片的可溶性蛋白含量,增加幼苗叶片内源超氧物歧化酶(SOD)和POD的活性,拮抗Hg2+胁迫对种子发芽率、苗高、日均增重及叶片可溶性蛋白含量的不利影响,Hg2+浓度较高时(≥50 mg.L-1),对种子发芽率和日均增

过量Mg~(2+)对土壤中酶活性的影响

目的研究过量Mg2+对土壤中脲酶、磷酸酶和过氧化氢酶活性的影响.方法通过在清洁土壤中投加不同质量浓度的MgC l2试剂,经过28 d的培养,期间在第1、3、7、14、28 d取样,测定土壤中的脲酶、磷酸酶和过氧化氢酶的活性.结果数据分析表明Mg2+对脲酶有激活作用,当Mg2+的质量分数为0.6%时,土壤脲酶活性提高最多,为91.6%,脲酶活性增加的程度为:0.6%>0.8%>0.4%>0.2%>1.0%>0,并且第1 d是观测脲酶变化的最佳时间.Mg2+对磷酸酶活性有先激活再抑制的作用,其活性在第3 d有大幅度增加,而从第14 d开始到第28 d,5个含不同质量分数Mg2+的土样,其磷酸酶活性全都低于空白试验。过氧化氢酶活性在试验的所有土样中均受到长效抑制.结论脲酶、磷酸酶和过氧化氢酶对Mg2+反映敏感,在Mg2+质量分数为0.6%时可以短期提高土壤肥力,但是长期大量的Mg2+介入土壤会严重影响土壤肥力,因此,可以考虑以Mg2+作为镁污染土壤的生态毒理指标.

The preparation and antioxidant activity of 2-[phenylhydrazine (or hydrazine)-thiosemicarbazone]-chitosan

Chitosan (CS) with two different molecular weight were modified by reacting with methyl hydrazine-dithiocarboxylate and methyl phenylhydrazine-dithiocarboxylate to give 2-(hydrazine-thiosemicarbazone)-chitosan (2-HTCHCS, 2-HTCLCS) and 2-(phenylhydrazine-thiosemicarbazone)chitosan (2-PHTCHCS, 2-PHTCLCS). The structure of the derivatives was characterized by FT-IR spectroscopy and elemental analysis. The antioxidant activities of the derivatives were investigated employing various established systems, such as hydroxyl radical (*OH)/superoxide anion (O-2(center dot-)) scavenging/reducing power and chelating activity. All of the derivatives showed strong scavenging activity on hydroxyl radical than chitosan and ascorbic acid (Vc), and IC50 of 2-HTCHCS, 2-HTCLCS, 2-PHTCHCS and 2-PHTCLCS was 0.362, 0.263, 0.531 and 0.336 mg/mL respectively. The inhibitory activities of the derivatives toward superoxide radical by the PMS-NADH system were strong. The results showed that the superoxide radical scavenging effect of 2-[phenylhydrazine (or hydrazine)-thiosemicarbazone]-chitosan were higher than that of chitosan. The derivatives had obviously reducing power and chelating activity. The data obtained from vitro models clearly establish the antioxidant potency of 2-[phenylhydrazine (or hydrazine)-thiosemicarbazone]-chitosan. (C) 2010 Elsevier B.V. All rights reserved.