Functions of indigenous animals in paddy fields: an in situ experiment on their effects on water quality,phytoplankton, weeds,soil structure,and rice growth

Paddy and Water Environment - Paddy fields are used for growing semiaquatic rice and are also important habitats for a diversity of aquatic animals, which may be beneficial for rice production....     

Evaluation of the thermal property of bovine intramuscular adipose tissue using differential scanning calorimetry

The thermal property of bovine intramuscular adipose tissue (IAT) was evaluated using differential scanning calorimetry (DSC) and compared with the melting point temperature (MP) of the fat extract of IAT, which was measured using the slip point method. The beef samples were classified according to the beef marbling score (BMS). Beef with a high BMS contained less protein than that with middle or low BMS. Beef with a high BMS contained significantly more fat than that with a low BMS (P < 0.05). The endothermic point temperature (EP) of IAT, measured by DSC, was significantly higher than the MP of IAT fat (P < 0.05). The EP showed no significant difference among the three marbling grade groups. Although the MP was correlated with the monounsaturated fatty acids (MUFA) content of IAT (R² = 0.505), there was no correlation between the EP and the MUFA (R² = 0.040). However, the EP of IAT treated with collagenase was relatively highly correlated with the MP (R² = 0.655). Thus, these results suggested that DSC analysis would give us the practical thermal information regarding the melt‐in the‐mouth of beef such as the gelatinization of collagen, along with the melting of fat in IAT.     

黄淮区油菜3 750~4 500 kg/ hm的产量结构研究

根据黄淮区油菜密度试验、2014和2015年度品种比较和区域试验结果,研究油菜产量各构成因素之间的关系。首次提出以群体概念“公顷角果数”替代单株角果数,并得出公顷角果数与每角粒数和千粒质量两个因素相比,在油菜产量构成中起着主导作用。根据实收产量、理论产量和公顷角果数之间的关系,得出黄淮区在当前品种所具有的每角粒数和千粒质量条件下,3 750 kg/hm时公顷角果数一般在4 725万左右;4 050 kg/hm时,公顷角果数达5 250万左右,而产量上升至4 590 kg/hm时,公顷角果数也随之上升到6 000万左右 。大约1.3万左右的角果可生产出1 kg油菜籽。明确这一指标的重要性,在于它为当前油菜的高产栽培指出方向,明确途径。同时,由于近年来育种者在提高油菜每角粒数和千粒质量的种质材料方面,作出大量工作,并创造出一批有实用价值的资源,所以,考虑到这两个因素的变化,未来油菜产量一定会有较大幅度地提高。     

采后UV-C辐照对马铃薯干腐病的抑制效应及相关酶活性的影响

为探讨不同辐照剂量的短波紫外线(UV-C)处理对马铃薯干腐病的抑制作用及相关酶活性的影响,以贮藏期间的马铃薯块茎为材料,经剂量为0、5、15、25、35、45 kJ·m-2的UV-C辐照,研究分析经损伤接菌后马铃薯块茎干腐病病斑及相关防御性酶[过氧化氢酶(CAT)、过氧化物酶(POD)、苯丙氨酸解氨酶(PAL)、丙二醛(MDA)]的变化情况。结果表明,损伤接菌后的马铃薯块茎,经剂量5~45 kJ·m~(-2)的UV-C辐照处理,块茎中MDA、PAL活性均显著降低,POD活性显著升高;剂量5 kJ·m~(-2)的辐照处理可显著提高损伤接菌后的马铃薯块茎中CAT活性;剂量5~45 kJ·m~(-2)的辐照处理均可有效抑制马铃薯块茎病斑直径的扩散,其中以35 kJ·m~(-2)处理效果最佳。本研究证实UV-C辐照有助于提高贮藏期间马铃薯块茎对于干腐病的抗性,为利用UV-C这种新型环保的马铃薯贮藏方法提供了理论参考。     

Degree of Suppression of Mouse Myoblast Cell Line C2C12 Differentiation Varies According to Chondroitin Sulfate Subtype

Chondroitin sulfate (CS), a type of glycosaminoglycan (GAG), is a factor involved in the suppression of myogenic differentiation. CS comprises two repeating sugars and has different subtypes depending on the position and number of bonded sulfate groups. However, the effect of each subtype on myogenic differentiation remains unclear. In this study, we spiked cultures of C₂C₁₂ myoblasts, cells which are capable of undergoing skeletal muscle differentiation, with one of five types of CS (CS-A, -B, -C, -D, or -E) and induced differentiation over a fixed time. After immunostaining of the formed myotubes with an anti-MHC antibody, we counted the number of nuclei in the myotubes and then calculated the fusion index (FI) as a measure of myotube differentiation. The FI values of all the CS-treated groups were lower than the FI value of the control group, especially the group treated with CS-E, which displayed notable suppression of myotube formation. To confirm that the sugar chain in CS-E is important in the suppression of differentiation, chondroitinase ABC (ChABC), which catabolizes CS, was added to the media. The addition of ChABC led to the degradation of CS-E, and neutralized the suppression of myotube formation by CS-E. Collectively, it can be concluded that the degree of suppression of differentiation depends on the subtype of CS and that CS-E strongly suppresses myogenic differentiation. We conclude that the CS sugar chain has inhibitory action against myoblast cell fusion.     

基于二维小波分析的丘陵山区景观特征尺度识别

以胶东半岛具有典型山地丘陵特征的栖霞市为例,选取A、B、C、D、E 5个代表性研究样区,用归一化植被指数（NDVI）和地形位指数作为植被和地形景观变量,分别应用sym2和Haar小波基,探讨二维小波分析在景观特征尺度识别中的有效性。结果表明：经小波变换,5个样区的景观图像表现出不同尺度和方向的结构特征,NDVI检测出农村居民点、工业用地的典型长宽尺度以及农田景观粒径;地形位指数检测出山体坡长和山脊线之间的距离;在景观相对破碎的B、C样区,小波方差变化幅度大于A、D、E样区,在地形起伏大的E样区,小波方差变化幅度大于A、B、C、D样区;经多尺度特征检验,栖霞山区景观最典型的特征尺度出现在3200 m和6400 m。研究结果为山区景观格局分析和土地利用提供科学依据。     

春油菜拌种对菌核病和跳甲的防效

为有效防控油菜病虫害,提升春油菜优质高效生产水平,以油菜菌核病和油菜跳甲为防治对象,在3种不同种植密度下,选择咯菌腈与吡虫啉、噻虫嗪混合或单独拌种,开展田间试验。结果表明,各拌种处理对油菜的出苗率有一定影响,其中杀虫剂拌种对油菜出苗率的影响大于杀菌剂;杀虫剂与杀菌剂混合拌种对菌核病和跳甲的防效均高于单独拌种;吡虫啉+咯菌腈拌种对油菜跳甲、春油菜菌核病的防效最高,分别可达66.80%和72.98%。春油菜菌核病病情指数随着播种密度的增加呈梯度式增加,拌种防效随密度增加而降低,综合产量分析,最佳播种密度为28.5～34.5万株/hm~2。     

最低收购价格下降对农户稻谷种植面积的影响——基于小农户和规模户比较的视角

利用黑龙江、四川、安徽3省的农户调研数据,分析了农户对最低收购价政策以及最低收购价下降的认知,并基于小农户和规模户的视角实证分析了最低收购价下降对农户稻谷种植面积的影响,最后考察了如果取消最低收购价政策,农户稻谷种植面积变动情况。结果表明：1）农户对最低收购价政策了解程度较高,规模户对最低收购价下降的了解程度明显高于小农户。2）全样本回归显示最低收购价下降对农户稻谷种植面积减少有显著的正影响,分别对小农户和规模户回归时发现,最低收购价下降仅对小农户稻谷种植面积的减少产生显著的正影响,而对规模户并没有显著影响。3）如果取消最低收购价,与小农户相比,规模户减少稻谷种植面积的意愿会更加强烈。     

花鲈免疫球蛋白的分离纯化及部分特性分析

分离纯化了花鲈(Lateolabrax japonicus)血清免疫球蛋白(Ig),并对其特性进行初步研究与分析.采用山羊-IgG(Goat-IgG)免疫花鲈并制备血清,分别采用硫酸铵分级沉淀法、A蛋白亲和层析法及Goat-IgG偶联亲和层析法提取花鲈Ig,对提取组份进行了蛋白浓度测定、间接ELISA效价测定、SDS-PAGE和Western-blotting分析.结果表明,采用硫酸铵分级沉淀法提取的花鲈Ig主要集中在硫酸铵饱和度为30%～50%的区间,其中45%饱和度硫酸铵富集的的抗体比活最高,ELISA效价为2×104/mg蛋白,比血清ELISA效价提高2.2倍;A蛋白柱亲和层析可得单一蛋白峰,洗脱峰集中在洗脱体积0.8～1.6 mL,处,占洗脱蛋白总量的76.2%,峰值的ELISA效价为1.37×105/mg蛋白,抗体得率为2.57%;Goat-IgG偶联Sephrose 4B亲和柱层析也可得单一蛋白峰,洗脱峰集中在洗脱体积1.4～2.8 mL处,占洗脱蛋白总量的72.4%,峰值的ELISA效价为1.39×105/mg蛋白,抗体得率为2.63%.以上3种提取方法均可得到79 kD的重链和29 kD轻链,表明可得到纯化的免疫球蛋白;采用鼠抗花鲈Ig血清和单抗AA5经Western-blotting证实提取成份为花鲈Ig.本研究表明,A蛋白柱和Goat-IgG偶联柱亲和层析均可用于花鲈Ig的提取,其中A蛋白柱法获得的洗脱峰值更为集中,抗体效价高,且提取过程不需要Goat-IgG免疫鱼体,是一种更为有效的免疫球蛋白提取方法.     

水稻镉吸收及其在各器官间转运积累的研究进展

随着土壤和大气沉降物中重金属污染的问题日益严峻,农作物重金属超标时有发生.土壤中的重金属难以降解,容易被植物根部吸收,在作物中积累;大气中的重金属沉降到叶片上,通过叶片吸收进入作物中,最终通过食物链被人类食用,危害人体健康.水稻是我国最重要的粮食作物,大米中存在镉超标问题.镉(Cd)是水稻的非必需元素,主要借助其他金属...