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1.
对粳稻农垦58经空间诱变产生的大粒型突变体进行大粒型性状的遗传分析和育种应用研究。结果表明,大粒型突变体的籽粒大小(以籽粒体积表示)表现为受多基因控制的数量性状。大粒型突变体谷粒细长,具馨香味,外观品质优,对粳稻的亲和性好,是一个罕见的优质米资源。以大粒型突变体为供体,高产、外观米质差的晚粳推广品种为受体,采用不饱和回交结合分离世代糙米外观品质鉴定的方法,将大粒型突变体的优质性状导入晚粳背景,选育出外观米质优的晚粳新品系。对采用不饱和回交方法改良数量性状进行了讨论。 Abstract:The inheritance and utilization of a stable large-grain mutant,selected from the induced generation derived from japonica Nongkeng 58 after space treatment carried by recoverable satellite,were analyzed.The results indicated that the grain volume of the large-grain mutant was quantitative trait controlled by multiple genes.The large-grain mutant had characteristics of slender grain,favorable scent,high apparent grain quality and good compatibility with japonica,and can be used as a valuable resource for improving grain quality.When high yield japonica variety with bad looking quality was used as a recurrent parent to cross with the mutant and a procedure of a limited backcross combined with identification of brown rice quality in segregation generations was applied,some japonica lines with good looking quality were developed.The utility of the limited backcross method for improvement of quantitative traits was discussed.  相似文献   
2.
大肠埃希菌耐药性水平传播实验研究   总被引:2,自引:0,他引:2  
目的研究重症监护病房(ICU)患者标本中分离的大肠埃希菌的耐药情况以及耐药性水平传播的实验研究。方法采取双纸片法(K-B)检测细菌的耐药性;产超广谱β-内酰胺酶(ESBLs)大肠埃希菌为供体菌,耐利福平大肠埃希菌(对其他抗生素敏感)作为受体菌进行接合实验;采用聚合酶链反应(PCR)技术扩增整合子和耐药基因。结果30株大肠埃希菌中产ESBLs菌株检出率为46.7%;接合培养后,接合菌携带23kb和25kb大质粒,而无供体菌中一系列小质粒;供体菌和接合菌均携带I型整合子。结论大肠埃希菌耐药性严重,且呈多重耐药性;产ESBLs菌株可通过质粒和整合子将耐药基因转移给敏感菌,导致耐药性传播。  相似文献   
3.
在2 703例遗传咨询门诊病例中检出9号染色体臂间倒位21例,将本组inv(9)的频率与普通群体inv(9)的频率作比较,并通过对伴有其它性状的inv(9)家系的分析,讨论了inv(9)的遗传效应问题。 Abstract: Twenty one cases of pericentric inversion of chromosome 9 were found in 2703 patients asking genetic counseling. The percentage of inv(9) in this group was compared with that in normal population. Two special pedigrees with inv(9) were analyzed and the genetic effects of inv(9) were discussed.  相似文献   
4.
采用原代培养和传代培养法, 对1头毛冠鹿的胚肺组织细胞进行观察,发现一种新的核型,其二倍体染色体数目为2n=48,核型公式为2M+2ST+42T+XX,出现1对大的末端着丝粒染色体,C-带显示该染色体与已报道的相关染色体同源,首次提出毛冠鹿B染色体多态,对其传递机制进行了探讨。 Abstract: Primary culture and subculture were adopted using lung cells of a female Elaphodus cephalophus' embryo. A new karyotype and a pair of big telocentric chromosomes were found. The diploid has 48 chromosomes, and the karyotype formula is 2M+2ST+42T+XX. C-banding analysis shows that these chromosomes are homologous with those reported relevant chromosomes. This article is the first to report the polymorphism of Elophodus cephalophus B-chromosomes and studies it's transmitted mechanism.  相似文献   
5.
利用农杆菌系统将超甜定基因导入烟草   总被引:8,自引:1,他引:7  
由pUR528构建中间载体pEHT9,再构建超甜定植物表达载体pBIT7。通过直接转化法将pBIT7导入农杆菌,然后利用农杆菌系统转化烟草。经PCR、PC R-S outhern和Southern杂交证实,超甜定基因已整合到烟草基因组中。 Abstract:pEHT9 was constructed from pUR528,and used for the construction of plant thaumatin expression vector pBIT7.Then pBIT7 was introduced to Agrobacterium through direct transformation.Subsequently tobacco was transformed through Agrobacterium-mediated system.It has been confirmed that thaumatin gene has integrated into the genome of transgenic tobacco by PCR,PCR-Southern and Southern blot analyses.  相似文献   
6.
作者于1996年在内蒙古调查了汉、回、蒙古族5项人类遗传学经典指标(拇指类型、环食指长、扣手、交叉臂、惯用手)。研究结果显示:(1)3个民族间拇指类型、扣手出现率存在显著性差异,交叉臂、惯用手出现率则无显著性差异,环食指长出现率蒙-汉、蒙-回间存在显著性差异;(2)拇指类型、扣手、惯用手出现率无性别间差异,环食指长出现率男女间存在显著性差异;(3)惯用手与扣手、惯用手与交叉臂间存在明显的相互关系,交叉臂与扣手之间则无关;(4)与国外人群比较,3个民族环指长出现率高,交叉臂R型出现率较高,扣手R型出现率较低,惯用手L型出现率高于印度的一些群体。 Abstract:Authors in vestigated 5 general indexes of anthrotogical genetics including pollical type,palmar digital formula,hand clasping,arm folding and handedness in Han,Hui and Mongol nationalities in 1996.The results showed as follows:(1)There were significant differences in the frequency of pollical type and hand clasping in 3 nationalities,but those of arm folding and handedness showed nosignificant difference and the frequencies of palmar digital formula between the Mongol and the Hui revealed significant difference.(2)There were no significant sexual difference in the frequency of pollical type,hand clasping and handedness while the long type (R) of ring finger revealed significant sexual difference.(3)There were obvious correlations between handedness and hand clasping,handedness and arm folding but no relation between arm folding and hand clasping.(4)In comparison with foreign ethnic groups,the 3 nationalities showed higher frequencies of long type (R) of ring finger and right-arm folding but the frequence right-hand clasping revealed slightly lower.The findings showed higher frequence of Left-Handedness than that of Indian population.  相似文献   
7.
8.
The 3' splice site of influenza A segment 7 is used to produce mRNA for the M2 ion-channel protein, which is critical to the formation of viable influenza virions. Native gel analysis, enzymatic/chemical structure probing, and oligonucleotide binding studies of a 63 nt fragment, containing the 3' splice site, key residues of an SF2/ASF splicing factor binding site, and a polypyrimidine tract, provide evidence for an equilibrium between pseudoknot and hairpin structures. This equilibrium is sensitive to multivalent cations, and can be forced towards the pseudoknot by addition of 5 mM cobalt hexammine. In the two conformations, the splice site and other functional elements exist in very different structural environments. In particular, the splice site is sequestered in the middle of a double helix in the pseudoknot conformation, while in the hairpin it resides in a two-by-two nucleotide internal loop. The results suggest that segment 7 mRNA splicing can be controlled by a conformational switch that exposes or hides the splice site.  相似文献   
9.
石油污染土壤植物-微生物修复研究进展   总被引:34,自引:0,他引:34  
依据国内外近10年来有关石油污染土壤生物修复研究的成果,综合阐述了石油污染土壤的植物修复、微生物修复及植物-微生物联合修复方法研究,重点讨论植物-微生物联合作用,主要包括植物根际微生物、根分泌物以及菌根对石油污染物降解的影响,提出了污染土壤原位修复中需要重视的问题.  相似文献   
10.
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