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141.
综述了非放射性地高辛(DIG)标记系统的原理和主要特点,介绍了地高辛标记核酸探针的主要标记方法,影响探针标记方法选择的因素,标记探针的显色检测方法及其在食用菌研究领域的应用。  相似文献   
142.
研究沙丘移动规律与空间分异特征有助于准确了解风沙活动的危害程度,为区域城镇规划和青藏高原国家生态安全屏障保护与建设提供参考.该研究基于Google Earth软件测量横向沙丘的形态参数与移动速度,分析了移动速度与方向的空间分异特征,以及移动速度对形态参数的响应.结果表明,1)柴达木盆地内沙丘移动速度介于0~23.53 ...  相似文献   
143.
Summary

Retrotransposons are major components of the genomes of most eukaryotic organisms and have resulted in the introduction of desirable traits in many crops, including fruit trees. Here, we describe a Ty3-gypsy-like retrotransposon associated with a short-catkin mutant in Chinese chestnut (Castanea mollissima), resulting in catkins that are < 20% the length of normal staminate catkins. A partial sequence of the retrotransposon, named CmRT1, detected by amplified fragment length polymorphism (AFLP) analysis, and its complete sequence were determined from the genome of Chinese chestnut (Castanea mollissima) using improved Tail-PCR. CmRT1 was 10,067 bp in length and shared high homology in its predicted amino acid sequence and motifs with other Ty3/gypsy-like retrotransposons. The 5’ long terminal repeat (LTR) of CmRT1 contained a TATA box and several cis-elements that were predicted to be important for processes involving abscisic acid, gibberellic acid, and auxins and in stress-mediated responses. Further characterisation of the transposition event that led to the short-catkin phenotype was performed using two pairs of primers that aligned with the flanking region of the LTRs. The expected PCR bands were observed only in genomic DNA from plants that showed the mutation. Finally, cloning and real-time qPCR analysis of an NADP-dependent alkenal double-bond reductase (CmADBR) target gene that was adjacent to CmRT1, revealed that CmADBR expression was significantly down-regulated in the short-catkin mutant. Taken together, these results suggest that the CmRT1 retrotransposon is responsible for the short-catkin phenotype.  相似文献   
144.
The pupal stage of the silkworm Bombyx mori Linnaeus lasts for approximately two weeks. However, prolongation of pupal duration would reduce the labor required to process and dry fresh cocoons. This study investigated the effects of BmKIT(3)(R) gene (from the Chinese scorpion Buthus martensii Karsch) transfer on the pupal development of B. mori using a Gal4/UAS binary transgenic system. Gal4 driven by a pupa-specific promoter BmWCP4 (from a B. mori wing-cuticle protein gene) or PDP (from a B. mori cocoonase gene), and BmKIT(3)(R) driven by a UAS cis-acting element were used to construct novel piggyBac-derived plasmids containing a neomycin-resistance gene (neo) controlled by the Bombyx mori nucleopolyhedrovirus (BmNPV) ie-1 (immediate-early gene) promoter and a green fluorescent protein gene (gfp) under the control of the B. mori actin 3 (A3) promoter. The vector was transferred into silkworm eggs by sperm-mediated gene transfer. Transgenic silkworms were produced after screening for neo and gfp genes, and gene transfer was verified by polymerase chain reaction and dot-blot hybridization. The larval development of the hybrid progeny of Gal4- and UAS-transgenic silkworms was similar to that of normal silkworms, but some pupae failed to metamorphose into moths, and the development of surviving pupae was arrested as a result of BmKIT(3)(R) expression. Moreover, Gal4 driven by the BmWCP4 promoter delayed pupal development more effectively than that driven by the PDP promoter in the Gal4/UAS binary transgenic system. Pupal durations of hybrid transgenic silkworm progeny with BmWCP4 and PDP promoters were approximately 5, 2, and 4 days longer, respectively, compared to corresponding normal silkworms, BmWCP4/Gal4, and UAS/BmKIT(3)(R) transgenic silkworms, respectively. These results suggest new avenues of research for prolonging the pupal duration of silkworms.  相似文献   
145.
袁鑫  曹望 《饲料广角》2006,(20):46-47
在生产经营活动中.说到成本.人们大都会想到直接成本与间接成本.或生产成本与营销成本等有形成本.但有一类无形成本却往往容易被忽视,那就是沟通成本。沟通成本是指由于沟通不畅等原因造成的营运成本增加。由于其无形的特征.所以由它导致的成本上升很难用一个确切的数字来描述。我国饲料工业的历史不过20余年.即使是一些成功的饲料公司也难以通过根深蒂固的企业文化来规范员工的言行。加之缺乏诚信环境和市场不规范现象比比皆是.人员流动频繁,盈利导向至上,员工缺乏系统培训即上岗.唯亲是用等,这都或多或少导致了企业内部的信息与沟通不畅,甚至阻塞逆反.互相扯皮推诿,进而导致沟通成本上升,隐性费用增加,企业市场竞争力下降。  相似文献   
146.
147.
通过表征受碱性过氧化氢降解的木质素磺酸盐,探索高效低耗的木质素降解条件。木质素磺酸盐与含有H2O2的0.5、1.0、2.0 mol/L的NaOH溶液分别在90、170℃下反应2 h。结果表明:碱性过氧化氢处理后木质素磺酸盐的Mw(重均相对分子质量)和Mn(数均相对分子质量)降低,而在170℃,1 mol/L NaOH溶液条件下获得最大程度的降解。木质素磺酸盐的相对分子质量在降解后分布相对集中,这表明木质素磺酸盐可直接用于开发木质素基材料而无需进一步分离。用碱性过氧化氢降解后,甲氧基摩尔分数降低。在170℃、2 mol/L NaOH溶液条件下4步加入过氧化氢,降解得到的木质素甲氧基摩尔分数下降57.4%。碱性硝基苯氧化的结果也表明在170℃下用2 mol/L NaOH溶液和4步添加H2O2处理后会得到最低的香草醛和香草酸产率,表明该条件下非浓缩的木质素结构被有效破坏。FTIR结果显示木质素的芳香结构消失。木质素磺酸盐利用碱性过氧化物降解,最佳条件是在2 mol/L NaOH溶液和170℃条件下,分4步添加H2O2。  相似文献   
148.
Polyphenols in Eucalyptus leaves (PE) were value resources due to various pharmacological activities, but data on the effect on laying hens are very scare. This study was conducted to determine the effect of PE on the laying performance, egg traits, meat quality, antioxidant status and liver tissues of laying hens. One hundred and twenty 256‐day‐old Yueqinhuang laying hens were randomly assigned to four treatment groups (different levels of PE at 0, 0.5, 0.8 and 1.2 g/kg diet) for 63 days with 15 replicates per group. Addition of 0.8 g/kg PE not only improved the egg trait by increasing the eggshell thickness and decreasing MDA production and cholesterol content in the egg yolk, but also significantly enhanced meat quality of hens, as suggested by the increase pH45 min (p < .01) and a* value, and decrease drip loss rate (p < .01). Meanwhile, under acute ethanol‐induced oxidative damage condition, supplementation of 0.8 g/kg PE enhanced the serum antioxidant status by increasing enzymatic activities (GSH‐PX, T‐SOD, T‐AOC), inhibited oxidative damage and provided protective effect to liver tissue. In conclusion, addition of 0.8 g/kg PE not only improved the egg traits and meat quality without obvious adverse effects, but also increased the serum antioxidant status of the hens and protected their liver tissue from ethanol‐induced oxidative damage. This study indicated that PE could be utilized as an effective feed additive for laying hens to improve health performance and egg traits.  相似文献   
149.
对虾夷扇贝、海湾扇贝及栉孔扇贝的原料基本工艺特性及蛋白质的组成及特点进行研究。对其软体部分(贝柱、外套膜、内脏、鳃、生殖腺)的质量组成及一般化学组成进行测定,用Duncan多重比较法对测定结果进行分析,比较其相互间差异性。对分离提取的肌原纤维蛋白、肌浆蛋白、胶原蛋白采用SDS-聚丙烯酰胺凝胶电泳测定分析,通过电泳图谱中蛋白质条带数目及分子量的分布情况比较得出3种经济贝类品种间和5种不同软体部分间各蛋白的差异性和相似性。  相似文献   
150.
利用pH调节法制备罗非鱼分离鱼蛋白.在临界pH条件下对罗非鱼肌肉蛋白进行处理得到肌肉溶解蛋白(Solution Muscle Protein,SMP),再利用等电点沉淀法对罗非鱼肌肉溶解蛋白进行分离得到肌肉分离蛋白(Isolated Muscle Protein,IMP),考查SMP的溶解率、黏度及IMP凝胶制品和常规中性漂洗(Conventional Wash)处理得到的蛋白凝胶制品的凝胶强度.以罗非鱼肌肉蛋白质在不同pH下的处理、转谷酰胺酶、食盐及凝胶化温度为因素,凝胶强度为目标参数进行正交试验设计.结果表明,与常规中性漂洗法相比, pH调节法制备的罗非鱼分离鱼蛋白具有回收效果好、功能性强的特点.  相似文献   
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