播量对直播稻郑旱10号产量及根系生理性状的影响

以直播稻品种郑旱10号为供试材料,探讨不同播量(90、120、150、180、210 kg/hm2)对直播稻郑旱10号产量及根系生理性状的影响,以期为直播稻适宜播量的选择提供理论依据与指导。结果表明,直播稻郑旱10号的产量随播量增加先显著增加后显著降低,当播量为150 kg/hm2时,产量最高,为10.64 t/hm2。直播稻郑旱10号的叶片净光合速率在齐穗后逐渐下降,随播量的增加先增加后降低,播量为150 kg/hm2时达到最大。地上部干质量随生育进程的推进而增加,根干质量、根系总吸收表面积和活跃吸收面积均随生育进程的推进先增加后降低,齐穗期达到最大;地上部、根干质量和根系总吸收表面积、活跃吸收面积在分蘖中期、穗分化始期和齐穗期均随播量增加而增加,而在成熟期随播量增加先增加后降低,播量为150 kg/hm2时达到最大。根系氧化力和根系生长素、玉米素+玉米素核苷含量均随生育进程的推进先增加后降低,穗分化始期达到最大;均随播量增加而降低,其中齐穗期和成熟期在播量大于150 kg/hm2时,降低更加明显。综上,当播量为150 kg/hm2时,直播稻郑旱10号的叶片净光合速率最大,成熟期地上部、根干质量和根系总吸收表面积、活跃吸收面积最大,根系氧化力、根系生长素、玉米素+玉米素核苷含量较大,产量最高。     

土壤甲烷单加氧酶活性测定的研究

以垃圾生物覆盖土、垃圾填埋场覆盖土、菜地土为材料,研究了土壤甲烷单加氧酶(Methane monooxygenase,MMO)活性的测定条件。结果表明:0.04 g kg-1 NaN3含量可抑制土壤生物活性,可作为土壤MMO活性测定时的对照;最适的底物丙烯浓度可为0.5%;培养时间对土壤MMO活性测定影响不大,但从测定的误差和可靠性考虑,可选用5 d作为土壤MMO活性测定的培养时间。统计分析表明:采用该方法测定的土壤MMO活性与其甲烷氧化潜力有很好的线性关系。     

旋毛虫肌幼虫可溶性抗原、排泄分泌抗原的电泳分析

本文报道了应用十二烷基硫酸钠一聚丙烯酰胺凝胶电泳（ＳＤＳ－ＰＡＧＥ），聚丙烯酰胺凝胶等电聚焦（ＩＥＦ）电泳及二维电泳（ＩＥＦ／ＳＤＳ－ＰＡＧＥ）对旋毛虫肌动虫排泄分泌（ＥＳ）抗原和肌幼虫可溶性抗原的分析结果。肌幼虫ＥＳ抗原经ＳＤＳ－ＰＡＧＥ后用考马斯亮蓝染色蛋白质，结果显示１６条蛋白带，分子量范围２１～８０ＫＤ，其中主带９条。ＩＥＦ电泳后分别用ＰＡＳ染多糖、考马斯亮蓝Ｒ－２５０染蛋白质、Ｎｉｌｅ＇ｓ蓝染脂、醋酸ａ－萘酯／坚固蓝染酪酶同工酶，结果肌幼虫ＥＳ抗原分别显示１６，２６、７及０条带；肌幼虫可溶性抗原分别显示２１、３８、４及１１条带。二维电泳后用考马斯亮蓝Ｇ－２５０染色多肤斑点，结果ＥＳ抗原显示多肽斑点６１个；肌幼虫可溶抗原显示１２２个多肽斑点。     

没食子酸对海鳗肌原纤维蛋白氧化及凝胶特性的影响

为研究没食子酸(GA)对海鳗肌原纤维蛋白(MP)氧化抑制作用和凝胶特性的影响,采用羟自由基氧化体系及不同质量分数GA对海鳗MP进行处理,考察不同浓度GA对海鳗MP氧化抑制作用,采用扫描电镜技术结合凝胶特性分析GA对MP的交联作用。结果表明,氧化使海鳗MP羰基含量、表面疏水性显著上升(P<0.05),总巯基含量、凝胶持水性显著降低(P<0.05)。不同浓度GA对MP氧化均有抑制作用,质量分数分别为0.10%、0.15%的GA抑制效果最佳,且凝胶持水性显著增强(P<0.05)。圆二色谱结果表明,质量分数分别为0.10%、0.15%的GA可使MP的α-螺旋、β-折叠含量有所增加。扫描电镜结果显示,添加质量分数为0.15%的GA后形成的MP凝胶结构更加致密、光滑。综上,质量分数为0.15%的GA能有效抑制海鳗MP氧化,并改善MP凝胶持水性和微观结构。本研究为GA在水产品加工及贮藏过程中的应用提供了理论依据和数据支撑。     

Insulin and gliclazide therapies improve liver lipid deposition in type 2 diabetic rats

AIM：To investigate the effect of insulin and gliclazide therapies on the liver fat accumulation in type 2 diabetic rats. METHODS：A high-fat diet plus low-dose streptozotocin was implemented to establish a type 2 diabetic rat model, and the rats were randomly divided into diabetes mellitus (DM) group, diabetic rats treated with insulin (INS) group, diabetic rats treated with gliclazide per os （PO） group, and normal control (NC) group. The diabetic rats in INS group and PO group were given insulin and gliclazide for 3 weeks, respectively. The changes of the liver fatty were evaluated with oil red O staining. Fasting plasma adiponectin concentration was measured by ELISA. The expression of adiponectin receptor 1 (AdipoR1) was detected by real-time PCR. The protein levels of AMP-activated protein kinase (AMPK), phosphorylated AMPK on threonine 172 (Thr172p-AMPK), sterol regulatory element-binding protein 1c (SREBP-1c), phosphorylated SREBP-1c on serine 372 (Ser372p-SREBP-1c), acetyl-CoA carboxylase (ACC), phosphorylated ACC on serine79 (Ser79p-ACC) and immunoglobulin-binding protein (BiP) in the liver homogenate were determined by Western blotting. RESULTS：Compared with the normal rats, in DM group, the presence of cytoplasmic lipid deposits was confirmed by oil red O staining. In INS group, these changes were significantly lower than those in DM group. Similar results were obtained in PO group. Insulin therapy significantly increased the plasma concentration of diponectin and liver tissue levels of AdipoR1 compared with DM group. At the same time, these 2 indicators returned to normal levels after gliclazide therapy. Thr172p-AMPK/AMPK, Ser372p-SREBP-1c/SREBP-1c and Ser79p-ACC/ACC expression ratios were significantly reduced in DM group compared with control values. The expression of BiP was increased on the contrary. After insulin therapy, Thr172p-AMPK/AMPK and Ser372p-SREBP-1c/SREBP-1c were significantly increased, and Ser79p-ACC/ACC and BiP returned to the normal levels. After gliclazide treatment, Thr172p-AMPK/AMPK and Ser372p-SREBP-1c/SREBP-1c returned to the normal levels, the expression ratio of Ser79p-ACC/ACC had no significant improvement compared with DM group, and the expression of BiP significantly declined. CONCLUSION：Both the insulin and gliclazide therapies reduce the lipid deposition in the liver of rats with type 2 diabetes by activating AMPK, but the extent and mechanism are not the same. In insulin therapy, AMPK restrains the expression of SREBP-1c directly, increases the phosphorylation of SREBP-1c, and affects SREBP-1c by inhibiting the endoplasmic reticulum stress. Gliclazide treatment, which has no effect on the lipid oxidation, reduces lipid deposition in the liver only through the phosphorylation of SREBP-1c and the suppression of the endoplasmic reticulum stress.     

Evaluation of etoxazole toxicity in the liver of Oreochromis niloticus

The effects of etoxazole were evaluated in freshwater fish Oreochromis niloticus from five different sublethal etoxazole concentrations in order to study the biochemical response, photometrically. No changes were observed in the activities of antioxidant enzymes such as superoxide dismutase (SOD, EC 1.15.1.1), catalase (CAT, EC 1.11.1.6), and glutathione peroxidase (GPx, EC 1.11.1.9). These were measured in liver after 1, 7, and 15 days of exposure to sublethal concentrations of 0.2, 0.4, 0.6, 0.8, and 1% of field application rate (134.75 ppm). This study also investigated the levels of neurotoxic effects by the determination of acetylcholine esterase (AChE EC 3.1.1.7) and sodium-potassium adenosine 5^′-triphosphatase (Na⁺K⁺-ATPase, EC 3.6.3.9) activities. The exposure of fish led to sharp depletion in AChE activity while there is no significant alteration in Na⁺K⁺-ATPase activity. Up to 80% decreases were observed in the AChE activity. Since no difference was found in the activity of glutamate-pyruvate transaminase (GPT, EC 2.6.1.2), etoxazole did not show hepatotoxic effect. The results of the present study show that increase in the malondialdehyde (MDA) contents and decrease in the AChE activity can be used as biomarkers for monitoring toxicity in etoxazole exposure.     

硒引发对紫花苜蓿种子抗氧化性能的影响

为探索外源硒引发对紫花苜蓿(Medicago sativa)种子抗氧化性能的影响,本试验用不同浓度(0,0.5,1.0,2.0,4.0和8.0 mmol·L-1)的亚硒酸钠溶液引发0,3,6,9和12 h后,分析其发芽率、丙二醛(malondialdehyde,MDA)含量、超氧化物歧化酶(superoxide dis...     

紫茄皮红色素抗氧化活性的研究

为了研究紫茄皮红色素的抗氧化活性,为其应用奠定理论基础。以紫茄皮为原料,以抗坏血酸、柠檬酸为对照,以Fenton反应产生羟基自由基(?OH),邻苯三酚自氧化反应产生超氧阴离子自由基(O2-?)为试验模型,采用紫外分光光度计测定紫茄子皮红色素对羟基自由基、超氧阴离子自由基的清除作用;以猪油作底物,采用烘箱贮藏法测定油脂的POV值,研究了紫茄皮红色素对油脂的抗氧化活性。结果表明：紫茄子皮红色素对上述自由基均有清除作用,对羟基自由基清除效果比柠檬酸、抗坏血酸好,且清除效果随着浓度的增大而增强,当浓度大于0.5 g/100 mL,对羟基自由基清除能力趋于稳定;对超氧阴离子自由基清除效果比柠檬酸、抗坏血酸好,最大抑制率为91%,当浓度大于0.6 g/100 mL后,对邻苯三酚自氧化的抑制作用趋于稳定;抑制脂质过氧化的程度强于柠檬酸和抗坏血酸,在0.7 g/mL的浓度下,协同增效作用趋于稳定。紫茄皮红色素在一定浓度范围内有很强的抗氧化活性。     

CH4 oxidation and N2O emissions at varied soil water-filled pore spaces and headspace CH4 concentrations

Emission of N₂O and CH₄ oxidation rates were measured from soils of contrasting (30-75%) water-filled pore space (WFPS). Oxidation rates of ¹³C-CH₄ were determined after application of 10 μl ¹³C-CH₄ l⁻¹ (10 at. % excess ¹³C) to soil headspace and comparisons made with estimates from changes in net CH₄ emission in these treatments and under ambient CH₄ where no ¹³C-CH₄ had been applied. We found a significant effect of soil WFPS on ¹³C-CH₄ oxidation rates and evidence for oxidation of 2.2 μg ¹³C-CH₄ d⁻¹ occurring in the 75% WFPS soil, which may have been either aerobic oxidation occurring in aerobic microsites in this soil or anaerobic CH₄ oxidation. The lowest ¹³C-CH₄ oxidation rate was measured in the 30% WFPS soil and was attributed to inhibition of methanotroph activity in this dry soil. However, oxidation was lowest in the wetter soils when estimated from changes in concentration of ¹²⁺¹³C-CH₄. Thus, both methanogenesis and CH₄ oxidation may have been occurring simultaneously in these wet soils, indicating the advantage of using a stable isotope approach to determine oxidation rates. Application of ¹³C-CH₄ at 10 μl ¹³C-CH₄ l⁻¹ resulted in more rapid oxidation than under ambient CH₄ conditions, suggesting CH₄ oxidation in this soil was substrate limited, particularly in the wetter soils. Application of and (80 mg N kg soil⁻¹; 9.9 at.% excess ¹⁵N) to different replicates enabled determination of the respective contributions of nitrification and denitrification to N₂O emissions. The highest N₂O emission (119 μg ¹⁴⁺¹⁵N-N₂O kg soil⁻¹ over 72 h) was measured from the 75% WFPS soil and was mostly produced during denitrification (18.1 μg ¹⁵N-N₂O kg soil⁻¹; 90% of ¹⁵N-N₂O from this treatment). Strong negative correlations between ¹⁴⁺¹⁵N-N₂O emissions, denitrified ¹⁵N-N₂O emissions and ¹³C-CH₄ concentrations (r=−0.93 to −0.95, N₂O; r=−0.87 to −0.95, denitrified ¹⁵N-N₂O; P<0.05) suggest a close relationship between CH₄ oxidation and denitrification in our soil, the nature of which requires further investigation.     

南极磷虾(Euphausia superba)脂肪与蛋白含量的季节变化

为了有效提取营养功效和附加值均更高的磷虾油,对南极磷虾(Euphausia superba)资源的综合开发利用提供参考,利用2013年7-8月和2013年12月-2014年5月在南乔治亚群岛和南设得兰群岛附近海域采集的南极磷虾样品,采用索氏抽提法,分别用无水乙醇、丙酮、石油醚、正己烷、乙酸乙酯、环己烷6种常见的有机溶剂作为提取试剂,对南极磷虾体内的脂肪进行提取,并确定最佳萃取溶剂.同时对南极磷虾脂肪、蛋白含量的季节变化及其与体长的关系进行了分析.结果显示,无水乙醇为南极磷虾脂肪提取的最佳溶剂.南乔治亚群岛海域7-8月南极磷虾脂肪含量和蛋白含量(干重)分别为(22.03±0.51)％和(64.52±0.16)％;其中,全长小于40 mm的磷虾个体,脂肪与蛋白含量均显著高于全长大于40 mm的个体(P＜0.05).从南极的初夏到秋末,南设得兰群岛海域的南极磷虾脂肪含量呈逐渐上升趋势,由12月的(19.83±0.04)％上升至翌年4月的最大值(30.584±0.02)％;5月则略有降低,为(28.66±0.03)％.与此相反,南极磷虾的蛋白含量则是12月最高、4月最低,分别为(66.75±0.14)％和(58.02±0.23)％;脂肪含量与蛋白含量呈显著负相关(P=0.005).研究结果对南极磷虾渔业及其生产安排具有直接的指导意义.