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91.
INTRODUCTIONOvariancancerisoneofthemostcommonfatalgynecologicmalignanciesin1.Towhomcorrespondenceshouldbeaddressed.theworld[1].Clinicaltreatmentofovariancancer,thoughwithgreatprogress,hasbeenimpededbyresistencetochemicaltherapy.Recently,inductionofapoptos…  相似文献   
92.
分子系统学研究中分子位点数与遗传差异信息可靠性的关系   总被引:38,自引:0,他引:38  
用桑蚕(包括不同生态地理品种59个及野桑蚕)和桑属植物(包括12个种和2个变种)两类截然不同的材料,探讨了分子系统学研究中RAPD分子位点数与遗传差异信息可靠性间的关系。发现:(1)所分析的位点数多少与所能提供系统信息的量及可靠性之间有明显的关系;(2)当位点数在20以下时,得到的遗传差异的结果极不可靠,随着位点数的增加所提供的信息量及可靠性增加。当位点数超过70个时,所提供的信息可靠性趋于稳定;(3)对桑蚕和桑属植物两种截然不同的材料的分析,均得相似结果。由此推论:在用RAPD进行生物系统学研究中,以分析70个左右位点数为好;这一结论受研究对象的影响小,在其它类似的研究中或许具有一定的参考价值。 Abstract:We studied the correlation between the number of RAPD-loci investigated and the reliability of the information on genetic variation analysis using quite different two-kind materials,silkworms(including 59 geographic varieties of Bombyx mori belonging to different ecotype,as well as Bombyx mandarina M.)and mulberries(including 12 species and 2 varieties).The results showed as follows:(1)There was obvious correlation between the numbers of RAPD-loci investigated and the reliability of the information on genetic variation analysis.(2)The data were not suitable for the genetic variation analysis when the number of RAPD-loci in vestigated was smaller than 20.The more RAPD loci were analyzed,the more accurate genetic diversity would be identified when the number of the locus was varied from 20 to 70.Furthermore,the stable information to be available is shown when the number exceeded 70.(3)The similar regularities mentioned above were observed in both silkworm and mulberry.In order to get reliable information of genetic variation in molecular phylogenetic studies,at least 70 RPD loci would be investigated.And the results obtained in this study might be referential for AFLP and RFLP analysis.  相似文献   
93.
绞股蓝总皂苷具有显著的降低血脂的作用,然而其机制尚未明确。课题组在前期研究的基础上,将33只C57BL/6J雄性小鼠随机分为3组,对照组(ND组)、模型组(HFD组)和绞股蓝皂苷组(HFD+GP组),分别给予维持饲料和高脂饲料,从16周开始,每日分别灌胃给予绞股蓝总皂250 mg/kg和等体积的空白溶剂,至38周,收集小鼠的血清和肝脏样本。通过HE染色观察肝脏组织的病理变化,检测血清总胆固醇和低密度脂蛋白水平,利用UPLC-MS/MS技术对小鼠肝脏14种胆汁酸含量进行分析,采用实时荧光定量PCR检测Cyp7a1、Cyp8b1、Fxr、Shp、Lrh1、Hnf4α基因表达水平。与对照组比较,模型组有明显的脂肪泡结构,给予绞股蓝总皂苷可以明显减轻肝脏组织的病理改变。与模型组比较,绞股蓝总皂苷可以显著降低血清中TC和LDL-C含量,显著降低肝脏中牛磺熊去氧胆酸(TUDCA)、甘氨鹅去氧胆酸(GCDCA)和甘氨脱氧胆酸(GDCA)含量,显著升高肝脏中鹅去氧胆酸(CDCA)、脱氧胆酸(DCA)和牛磺脱氧胆酸(TDCA)含量,并在上调肝脏Cyp7a1、Cyp8b1、Fxr和Lrh1基因表达的同时下调Shp的基因表达。绞股蓝总皂苷降脂作用的潜在靶点可能与FXR介导的胆汁酸代谢通路有关,为进一步深入探讨绞股蓝总皂苷降脂作用及其机制提供了参考。  相似文献   
94.
Analysis of cytochrome P450 genes in silkworm genome (Bombyx mori)   总被引:5,自引:0,他引:5  
Cytochrome P450 monooxygenases (P450) are im-portant metabolic enzymes involved in the metabolism not only of a wide range of endogenous compounds such as fatty acids, steroids, hormones or vitamins, but also of exogenous substrates such as drugs, chemicals including environmental pollutants, such carcinogens as polycyclic aromatic hydrocarbons, and pesticides[1]. P450s are found virtually in all aerobic organisms, including organisms as diverse as in insects, plants, mammals, birds and bacter…  相似文献   
95.
Saccharomyces cerevisiae is one of the most im- portant heterologous expression systems. The stability and copy number of expression plasmid in the host are the important factors to affect the expression levels of foreign genes[1―3]. pHC11 is a yeast episomal plasmid constructed by our laboratory[4]. It contains the entire sequence of the 2μ plasmid without disrupting its coding elements and other functional regions. The stability and copy number of pHC11 are relatively high. Making use of…  相似文献   
96.
Timed embryo transfer programs for management of donor and recipient cattle   总被引:2,自引:0,他引:2  
Currently, timed ovulation induction and fixed-time artificial insemination (FTAI) in superstimulated donors and synchronization protocols for fixed-time embryo transfer (FTET) in recipients can be performed using GnRH or estradiol plus progesterone/progestin (P4)-releasing devices and prostaglandin F (PGF2α). The control of follicular wave emergence and ovulation at predetermined times, without estrus detection, has facilitated donor and recipient management. However, because Bos taurus cows have subtle differences in their reproductive physiology compared with Bos indicus cattle, one cannot assume that similar responses will be achieved. The present review will focus on the importance of orchestrating donor and recipient management to assure better logistics of procedures to achieve more desirable results with embryo collection and transfer. In addition, this will provide clear evidence that the use of FTAI in superstimulated donors and FTET in embryo recipients eliminates the need to detect estrus with satisfactory results. These self-appointed programs reduce labor and animal handling, facilitating the use of embryo transfer in beef and dairy cattle.  相似文献   
97.
(一)引言腐蚀标本的制作方法早在1863年已由苏联解剖学家И.В.布亚力斯应用于解剖学的研究与教学,最近又经А.А.克勒苏斯卡娅的改进,使这种方法能够更广泛的应用到教学及研究,在苏联各  相似文献   
98.
The energetic consequences of fighting, which may depend on environmental conditions, can be an important factor shaping contest strategy and duration. Energy expenditure may be costly to fitness because it depletes reserves that could otherwise have been allocated to reproduction, and metabolites are produced that may constrain subsequent activities. We examined the variation in the metabolic consequences of fighting in relation to hypoxia. Contests were staged between pairs of size-matched male shore crabs Carcinus maenas L., under a range of water oxygen tensions (between 10 and 100% oxygen saturation) which crabs experience in their natural habitat. Fighting under normoxic and hypoxic conditions resulted in significantly elevated concentrations of haemolymph metabolites (L-lactate and glucose) compared with crabs at rest. However, these concentrations were much lower than in crabs that had been walking on a treadmill. Glycogen concentrations differed only under hypoxic conditions: glycogen stores were reduced in crabs after fighting and this reduction was similar to that after exercise on a treadmill. Contests were shorter when they were staged below a water P o2of 6.7 kPa ( approximately 30% normoxia). As water oxygen tensions were reduced, fighting crabs had greater concentrations of L-lactate and glucose in their blood and tissues whilst glycogen stores were reduced. Fights became shorter when crabs were exposed to severe hypoxia (P o2=2 kPa) for increasing lengths of time, and blood L-lactate concentrations increased. The results suggest that as fights progressed, crabs experienced an increasing metabolic debt, in the form of accumulation of L-lactate and a reduction in energy stores, which was amplified by hypoxic conditions. Copyright 1999 The Association for the Study of Animal Behaviour.  相似文献   
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