Review of milk let-down in camels and proposition of a milk recording method     

Boujenane  Ismaïl 《Tropical animal health and production》2020,52(6):2845-2853

Tropical Animal Health and Production - The aim of this article was to review the milk let-down in camels and to propose a simple milk recording method. Milking of camels generally starts between 1...  相似文献   

Changes in growth and nitrogen assimilation in barley seedlings under cadmium stress     

Naïma Boussama  Omar Ouariti  Mohamed Habib Ghorbal 《Journal of plant nutrition》2013,36(4-5):731-752

Barley (Hordeum vulgare L. cv. Martin) plants grown in solution culture, were exposed to increasing cadmium (Cd) concentration (0, 5, 10, 25, 50, and 100 μM) for a duration of 12 days. The sequence of important biochemical steps of nitrate (NO₃) assimilation were studied in roots and shoots as a function of external Cd concentration. Cadmium uptake in roots and shoots increased gradually with Cd concentration in the medium. This Cd accumulation lowered substantially root and shoot biomass. The nitrate reductase (NR, EC 1.6.6.1) and nitrite reductase (NiR, EC 1.6.6.4) activities declined under Cd stress. Concurrently, tissue NO₃ contents and xylem sap NO₃ concentration were also decreased in Cd‐treated plants. These results suggest that Cd could exert an inhibitory effect on the assimilatory NO₃ reducing system (NR and NiR) through a restriction of NO₃ availability in the tissues. We therefore examined, in short‐term experiments (12 h), the impact of Cd on NO₃ uptake and the two reductases in nitrogen (N)‐starved plants that were pretreated or not with Cd. It was found that Cd induced inhibition of both NO₃ uptake and activities of NR and NiR, during NO₃ induction period. The possible mechanisms of Cd action on NO₃ uptake are proposed. Further, in Cd‐grown plants, the glutamine synthetase (GS, EC 6.3.1.2) showed a decreasing activity both in shoots and roots. However, increasing external Cd concentration resulted in a marked enhancement of glutamate dehydrogenase (NADH‐GDH, EC 1.4.1.2) activity, coupled with elevated levels of ammonium (NH₄ in tissues. On the other hand, the total protein content in Cd‐treated plants declined with a progressive and substantial increase of protease activity in the tissues. These findings indicate that under Cd stress the usual pathway of NH₄ assimilation (glutamine synthetase/glutamate synthase) can switch to an alternative one (glutamate dehydrogenase). The changes in all parameters investigated were concentration‐dependent and more marked in roots than shoots. The regulation of N absorption and assimilation by Cd in relation to growth and adaptation to stress conditions are discussed.  相似文献   

木质素合成关键基因在软籽和硬籽石榴中的表达及代谢物分析     

史江莉  王飒  王磊  仝瑞冉  王森  胡青霞  万然  简在海  郑先波  陈延惠 《河南农业大学学报》2022,56(1):61-69,105

[目的]基于木质素代谢,探究软籽和硬籽石榴种子硬度形成机制,为培育优良软籽石榴提供基因资源.[方法]采用超高效液相色谱和串联质谱联用测定了'突尼斯软籽'和'泰山红'硬籽石榴成熟期种子中木质素途径小分子物质含量;运用Real-time PCR技术分析木质素途径中12个关键基因在4个种子发育期的时空表达和组织特异性表达.[...  相似文献   

小麦糯性基因多重PCR体系的建立   总被引：2，自引：0，他引：2  

陈龙  侯彩玲  谭光轩  于美玲  卢龙斗  殷贵鸿 《麦类作物学报》2009,29(5):747-751

为建立通过一次反应能够同时鉴定3个小麦糯性基因(Wx-A1、Wx-B1和Wx-D1)的多重PCR反应体系,研究了PCR反应组分和循环参数对多重PCR反应结果的影响.结果表明,反应体系中的引物浓度比例和反应的Tm值是多重PCR成功的关键,当引物浓度比例(SSR/MAG267)为1(0.1 μmol/L∶0.1 μmol/L)～1.22(0.11 μmol/L∶0.09 μmol/L)、Tm为58℃时,Wx-A1、Wx-B1、Wx-D1基因的多重PCR结果最好.该多重PCR方法能快速高效地鉴定3个Wx基因,可用于糯麦选育和小麦品质育种的复合分子标记辅助选择.  相似文献   

西藏地区油菜遗传改良     

萨如拉  拉巴扎西 《西藏农业科技》2008,30(4):41-43

分析了西藏未来油菜遗传改良趋势及其以后的发展思路;还提出了西藏油菜科研工作中存在的主要问题及其解决的措施。  相似文献   

刚果红分光光度法测定链霉素     

刘飒  刘绍璞  谢锂纱  宋彦琪  胡小莉 《西南大学学报》2008,30(9)

在pH=5 0 的Britton-Robinson缓冲溶液中, 链霉素与刚果红形成离子缔合物, 导致溶液的吸收光谱变化, 在 497 nm处产生明显的褪色作用. 链霉素浓度在0 01～2 8 μg/mL的范围内与吸光度值呈良好的线性关系. 据此建立了测定链霉素的分光光度法, 摩尔吸光系数(ε)为 1 19×105 L/(mol·cm). 研究了适宜的反应条件和分析化学性质, 将方法用于尿样和蜂蜜中链霉素残留量测定, 结果满意.  相似文献   

黄华属植物叶表皮特征及其生物学意义   总被引：11，自引：0，他引：11  

萨仁  苏德毕力格  陈家瑞 《草地学报》2000,8(1):65-76

在光学显微镜下观察披针叶黄华复合体、高山黄华复合体及黄华属其它种的叶表皮特征。结果表明,表皮细胞形状、垂周壁式样及气孔器类型具有重要的分类学意义。表皮细胞形状为多边型和不规则型,垂周壁式样为平直或具波纹。黄华属植物除新疆黄华,之字枝黄华,东亚黄华,柔毛黄华上表皮无气孔外,其余的上下表皮均具气孔,气孔器类型多为不规则型,只有紫花黄华为不等细胞型,有些无规则型中稍混有不等细胞型。笔者认为气孔器类型对划分属内种上等级具有一定价值。对披针叶黄华复合体、高山黄华复合体和黄华属不同种间气孔指数方差分析结果表明,气孔指数在居群水平及不同种间变化差异极显著,气孔大小及气孔指数主要受环境因子的控制。  相似文献   

Histological alterations in gills of shrimp Litopenaeus vannamei in low‐salinity waters under different stocking densities: Potential relationship with nitrogen compounds          下载免费PDF全文

Marcela G. Fregoso‐López  María S. Morales‐Covarrubias  Miguel A Franco‐Nava  Javier Ramírez‐Rochín  Juan F Fierro‐Sañudo  Jesús T Ponce‐Palafox  Federico Páez‐Osuna 《Aquaculture Research》2017,48(12):5854-5863

Two experimental modules with different stocking densities (M1 = 70 and M2 = 120 shrimp /m²) were examined weekly over a culture cycle in tanks with low‐salinity water (1.9 g/L) and zero water exchange. Results showed survival rates of 87.7 and 11.9% in M1 and M2, respectively. Water temperature, pH, dissolved oxygen, electrical conductivity and chlorophyll a were not significantly (p > .05) different between modules. In contrast, the concentrations of nitrogen compounds were significantly (p < .05) different between modules, except nitrite‐N (M2 were 2.31 ± 1.38 mg/L N‐TAN, 0.18 ± 0.49 mg/L N‐NO₂^? and 6.83 ± 6.52 mg/L N‐NO₃^?; in M1: 0.97 ± 0.73 mg/L N‐TAN, 0.05 ± 0.21 mg/L N‐NO₂^? and 0.63 ± 0.70 mg/L N‐NO₃^?). When waters of both modules reached higher levels of ammonia and nitrite, histological alterations were observed in gills. The histological alterations index (HAI) was higher in M2 (5‐112) than in M1 (2‐22).  相似文献   

额尔齐斯河银鲫形态学及COI基因序列分析   总被引：1，自引：0，他引：1  

孟玮  郭焱  海萨  杨天燕  高攀 《淡水渔业》2010,40(5)

采用传统形态学方法和线粒体COI基因序列分析对额尔齐斯河银鲫(Carassius auratus gibelio)两个群体的形态和遗传差异进行了比较。结果显示:通过对8个可量性状和20个框架数据的主成分分析可以看出,两个群体分别占据两个不相重叠的区域,两个群体在形态上存在明显分化。COI基因序列分析显示,两群体之间遗传距离为0.012,群体间遗传距离是群体内最大遗传距离的4倍,两群体间在编码的氨基酸序列上出现了一处替换,群体遗分化指数值为0.96078,基因流值为0.01,表明群体间缺乏基因交流,群体间有明显的遗传分化。  相似文献   

基于线粒体COI基因序列的亚东鲑DNA条形码研究   总被引：7，自引：0，他引：7  

孟玮  杨天燕  海萨  海沙尔·阿那斯 《水产学杂志》2010,23(1):6-10

以亚东鲑为研究对象,测定分析了线粒体COI基因638bp碱基序列,探讨了该基因作为DNA条形码在鲑科三种鱼类(亚东鲑、大西洋鲑和红点鲑)鉴定方面的可行性和有效性。亚东鲑33个个体共享1种单倍型。利用Kimura-2模型分析得到亚东鲑与大西洋鲑遗传距离最小,为0.079;大西洋鲑与红点鲑遗传距离最大,为0.141;亚东鲑与红点鲑遗传距离为0.120。基于COI基因片段序列构建的NJ显示,亚东鲑和大西洋鲑首先聚到一起,然后再与红点鲑相聚。结果表明COI基因片段作为三种鱼类DNA条形码进行分类鉴定具有一定可行性。  相似文献