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1.
中国白菜RAPD分子遗传图谱的构建   总被引:17,自引:0,他引:17  
以芜菁(Brassica campestris L.ssp.rapifera Metzg)和结球白菜(B.carnpestris L.ssp .Plkinensis(Lour.)Oisson)杂交的F2群体为试材,采用RAPD标记,用84个10核苷酸随机引物构建了白菜的RAPD遗传图谱。该图谱覆盖基因组的1632.4cM(certi Morgan)标记间的平均间隔为16.5cM。其中最长的连锁群为  相似文献   

2.
鉴定了E.coliHB101和JM110的部分遗传标记,作为受体菌分别用于BstNI同功酶限制-修饰系统中限制性内切酶(Restrictionendonuclease,简称R)基因和甲基化酶(Methylase,简称M)基因表达的检测。用外切酶II单向删切含RM基因的DNA片段,获得23个缺失突变亚克隆。通过检测各亚克隆表达的R酶和M酶活性,将R和M基因分别定位在距克隆位点PstI的02→14kb和15→3.3kb范围内。分析表明:该系统属于I类限制修饰系统,两个基因受控于不同的启动子;该系统与E.Coli染色体编码的胞嘧啶DNA甲基转移酶(Dcm)的识别序列相同,后者的甲基化作用也能阻止R酶的切割。R+M-的重组质粒对Dcm+和Dcm-的宿主都是致死性的,这说明在进化过程中,与R基因紧密连锁的M基因对系统的存在至关重要  相似文献   

3.
青州仰天山地区夏季鸟类垂直分布的研究王庆忠,王大科(山东潍坊教育学院生物系,青州262500)VerticalDistributionofSummerBirdsinYangtianMountainousDistrictofQingzhou.¥Wang...  相似文献   

4.
沈阳市东陵区丘陵坡地坡面太阳直射光的分布及其分析郭林海(中国科学院沈阳应用生态研究所,110015)DistributionofDirectSolarRadiationonHillySlopesofDonglingDistrictofShenyangMunicipalityandItsAnalysis¥GuoLinhai(InstituteofAppliedEcology,AcademiaSinica,Shenyang110015).ChineseJournalofEcology,1993,12(1):59-61.Basedonthelatest1:50000topographicmap,the1:100000slopegradationmapisdrawnoutandareacalculationismade.Thedirectsolarradiationintypicalsitesofthedistrictismeasuredandcalculated,andthevariationcurvesofannualfluxofdirectsolarradiationonvariousslopedirecti  相似文献   

5.
TGF—β家族的细胞信号转导   总被引:2,自引:0,他引:2  
Huang JF  Fang DC  Lu R 《生理科学进展》1999,30(3):255-258
转化生长因子β(TGF-β)家族成员与各自的膜受体结合后,使通路限制性(pathway-restricted)SMADs磷酸化,后者再与Smad4形成杂聚体并转位至细胞核,调节一些基因的转录而产生生物学效应。抑制性SMADs可阻断通路限制性SMADs的磷酸化。  相似文献   

6.
白蔹单宁化学成分的研究   总被引:12,自引:0,他引:12  
从白蔹Ampelopsis japonica(Thunmb.)Makino的乙酸乙酯提取物中分离出5个单宁化合物。经光谱分析和化学方法鉴定,它们为没食子酸(gallic acid,1),1,2,6-三氧-没食子酰基-β-D-吡喃葡萄糖(1,2,6-tri-O-galloy1-β-D-glucopyranoside,2),1,2,3,6-四氧-没食子酰基-β-D-吡喃葡萄糖(1,2,4,6-tetr  相似文献   

7.
陈建  邢沈阳 《蛛形学报》1999,8(1):34-37
对取食不同食物(棉铃虫Helicoverpaarmigera,摇蚊Chironomussp,果蝇Drosophilamelanogaster及其组合)的三突花蛛(Misumenopstricuspidatus)历期和体重进行了比较研究,结果表明,取食混合食物的三突花蛛历期缩短,干重增大。  相似文献   

8.
从毛裂蜂斗菜(pdtasilex tricholobus Franch。)的石油醚提取物中首次分离得到6个化合物,运用IR,EI-MS,HRMS,^1H NMR,^13C NMR,DEPT等光谱方法确定了它们的结构。它们分别是:A1-β-谷甾醇;A2,三十二碳酸,A3,羽扇豆醇;A4,Bakkenolide-B;A5,Bakkenolide-D和A6,akkenolide-E。  相似文献   

9.
白菜型油菜与蓝花子杂交的初步研究   总被引:6,自引:0,他引:6  
吴沿友  罗鹏   《广西植物》1998,18(1):54-57
通过胚胎培养,成功地获得了白菜型油菜(Brasicacampestris)与蓝花子(RaphanussativusLvarraphanistroidesMakino)的属间杂种。该杂种具有两种类型;一种为大花类型,一种为小花类型。对它们进行花粉母细胞减数分裂的观察结果表明:小花类型为未加倍的杂种MI,存在19个未配对染色体,大花类型为加倍或部分加倍杂种,加倍类型MI,19个二价体排列在赤道板上;部分加倍类型AI,具有10-10-9的染色体组分割现象。大花类型具有可育性;它能够产生很多n=19及n=9、n=10的正常配子。染色体组分割能够产生倍半二倍体,它能用来研究染色体的功能和开展染色体工程。  相似文献   

10.
杜丽萍  余其兴 《遗传学报》1998,25(4):308-314
采用DNaseI超敏感性分析和限制性内切酶介导的原位切口平移技术(RestrictionEnzymeNickTranslation,RE-NT)对黄鳝二价体基因组结构进行了分析研究,已知DNaseI超敏感性与潜在活性基因分布密切相关,结果表明:经DNaseI介导的原位切口平移处理,在黄鳝二价体上可可展现类D带带型,而由限制性内切酶介导的原位切口平移结果显示,AluI和MspI均在黄鳝二价体上诱导产  相似文献   

11.
Vitamin D, the sunshine vitamin, has been recognized for almost 100 years as being essential for bone health. Vitamin D provides an adequate amount of calcium and phosphorus for the normal development and mineralization of a healthy skeleton. Vitamin D made in the skin or ingested in the diet, however, is biologically inactive and requires obligate hydroxylations first in the liver to 25-hydroxyvitamin D, and then in the kidney to 1,25-dihydroxyvitamin D. 25-Hydroxyvitamin D is the major circulating form of vitamin D that is the best indicator of vitamin D status. 1,25-dihydroxyvitamin D is the biologically active form of vitamin D. This lipid-soluble hormone interacts with its specific nuclear receptor in the intestine and bone to regulate calcium metabolism. It is now recognized that the vitamin D receptor is also present in most tissues and cells in the body. 1,25-dihydroxyvitamin D, by interacting with its receptor in non-calcemic tissues, is able to elicit a wide variety of biologic responses. 1,25-dihydroxyvitamin D regulates cellular growth and influences the modulation of the immune system. There is compelling epidemiologic observations that suggest that living at higher latitudes is associated with increased risk of many common deadly cancers. Both prospective and retrospective studies help support the concept that it is vitamin D deficiency that is the driving force for increased risk of common cancers in people living at higher latitudes. Most tissues and cells not only have a vitamin D receptor, but also have the ability to make 1,25-dihydroxyvitamin D. It has been suggested that increasing vitamin D intake or sun exposure increases circulating concentrations of 25-hydroxyvitamin D, which in turn, is metabolized to 1,25-dihydroxyvitamin D(3) in prostate, colon, breast, etc. The local cellular production of 1,25-dihydroxyvitamin D acts in an autocrine fashion to regulate cell growth and decrease the risk of the cells becoming malignant. Therefore, measurement of 25-hydroxyvitamin D is important not only to monitor vitamin D status for bone health, but also for cancer prevention.  相似文献   

12.
The typification of six Linnaean Datura names ( D. stramonium, D. metel, D. arborea, D. ferox, D. fastuosa and D. tatuld ) is discussed. A modification to the typification of D.fastuosa is proposed and a lectotype for D. tatula is designated here.  相似文献   

13.
The second to fourth digit ratio (2D:4D) is sexually dimorphic, with lower mean values in males compared to females. It has been suggested that the sex difference in 2D:4D is determined prenatally, 2D:4D is negatively related to prenatal testosterone and positively to prenatal oestrogen, and that 2D:4D is a marker for levels of sex steroids during brain organisation. There is growing evidence that many sex-dependent behaviours are correlated with 2D:4D. However, there is no direct evidence for an effect of prenatal sex steroids on the digit ratio. The response to prenatal testosterone is dependent on the amount produced and the foetal sensitivity to the hormone. Variation in the X-linked androgen receptor gene (AR) determines sensitivity to testosterone. Alleles of AR with low numbers of CAG triplets respond to testosterone with high transactivational activity, while high numbers of CAG's are associated with increased insensitivity to testosterone. We show in a sample of 50 men (49 Caucasian subjects, 1 Caucasian/Chinese subject) that 2D:4D is a phenotypic correlate of AR structure. Right-hand 2D:4D was positively correlated with CAG number and individuals with low 2D:4D in their right hand compared to left hand had AR alleles with low CAG numbers. We discuss the implications of our findings for our understanding of the aetiology of 2D:4D, its relationships with sex-dependent behaviours, and the evolutionary implications of variation in 2D:4D and AR.  相似文献   

14.
Yamuna Narayanan 《Genetics》1973,73(2):319-350
The phylogenetic relationships among the species of the D. robusta group were investigated by the analysis of chromosomal differences. Six of the ten known members of the D. robusta group were available for the study: D. colorata and D. robusta from the United States, and D. sordidula, D. pseudosordidula, D. lacertosa, and D. moriwakii from Japan. Analysis of the metaphase chromosomes from larval ganglion cells suggests that D. moriwakii and D. colorata, with rod-shaped X-chromosomes, are the more ancestral species, while D. sordidula, D. pseudosordidula, D. robusta, and D. lacertosa, with V-shaped X-chromosomes, are derived. The ancestral position of D. colorata and D. moriwakii is further strengthened by the fact that these are the two species in the D. robusta group that are cytologically closest to D. nigromelanica of the related D. melanica group. Of the four derived species, D. sordidula was found to be the closest to the ancestral species. The phylogeny based on the analysis of the gene sequences in the homologous chromosomes agreed with that indicated by the metaphase chromosomes. Since all attempts to obtain hybrids were unsuccessful except for the cross involving D. moriwakii females and D. colorata males, photographic maps of the salivary chromosomes were used to determine homology between the chromosomes of the different species. Evidence is presented to indicate that the D. robusta group originated in Asia (Japan), and that there were two migrations to the New World, the first leading to D. robusta, and the second to D. colorata. It is suggested that the route of migrations was across the Bering Land Bridge, and further, that the migrations occurred during the period from late Oligocene to middle Miocene, 20-25 million years ago.  相似文献   

15.
We have recently shown that during in vivo photoinhibition the D1 protein is degraded via a modified form, designated D1*. Depending on light conditions, the amount of D1* varies in leaves between 0 and 50% of total D1 content. By isolating thylakoids from leaves acclimated to different light levels, and performing photoinhibition experiments on these thylakoids, the following results on D1 protein degradation were obtained: (i) the protease involved in D1 degradation requires activation by light; (ii) neither acceptor nor donor side photoinhibition of PSII induces formation of D1* in vitro; (iii) in isolated thylakoids, the transformation of D1 to D1* can be induced in low light in the presence of ATP, which suggests that D1* is a phosphorylated form of the D1 protein; (iv) D1*, induced either in vivo or in vitro, is much less susceptible to degradation during illumination of isolated thylakoids than the original D1 protein. We suggest that the modification to D1* is a means to prevent disassembly of photodamaged photosystem II complex in appressed membranes.  相似文献   

16.
Goto-Ito S  Ito T  Ishii R  Muto Y  Bessho Y  Yokoyama S 《Proteins》2008,72(4):1274-1289
Methylation of the N1 atom of guanosine at position 37 in tRNA, the position 3'-adjacent to the anticodon, generates the modified nucleoside m(1)G37. In archaea and eukaryotes, m(1)G37 synthesis is catalyzed by tRNA(m(1)G37)methyltransferase (archaeal or eukaryotic Trm5, a/eTrm5). Here we report the crystal structure of archaeal Trm5 (aTrm5) from Methanocaldococcus jannaschii (formerly known as Methanococcus jannaschii) in complex with the methyl donor analogue at 2.2 A resolution. The crystal structure revealed that the entire protein is composed of three structural domains, D1, D2, and D3. In the a/eTrm5 primary structures, D2 and D3 are highly conserved, while D1 is not conserved. The D3 structure is the Rossmann fold, which is the hallmark of the canonical class-I methyltransferases. The a/eTrm5-defining domain, D2, exhibits structural similarity to some class-I methyltransferases. In contrast, a DALI search with the D1 structure yielded no structural homologues. In the crystal structure, D3 contacts both D1 and D2. The residues involved in the D1:D3 interactions are not conserved, while those participating in the D2:D3 interactions are well conserved. D1 and D2 do not contact each other, and the linker between them is disordered. aTrm5 fragments corresponding to the D1 and D2-D3 regions were prepared in a soluble form. The NMR analysis of the D1 fragment revealed that D1 is well folded by itself, and it did not interact with either the D2-D3 fragment or the tRNA. The NMR analysis of the D2-D3 fragment revealed that it is well folded, independently of D1, and that it interacts with tRNA. Furthermore, the D2-D3 fragment was as active as the full-length enzyme for tRNA methylation. The positive charges on the surface of D2-D3 may be involved in tRNA binding. Therefore, these findings suggest that the interaction between D1 and D3 is not persistent, and that the D2-D3 region plays the major role in tRNA methylation.  相似文献   

17.
The D1 protein of Photosystem II (PSII) is recognized as the main target of photoinhibitory damage and exhibits a high turnover rate due to its degradation and replacement during the PSII repair cycle. Damaged D1 is replaced by newly synthesized D1 and, although reasonable, there is no direct evidence for selective replacement of damaged D1. Instead, it remains possible that increased turnover of D1 subunits occurs in a non-selective manner due for example, to a general up-regulation of proteolytic activity triggered during damaging environmental conditions, such as high light. To determine if D1 degradation is targeted to damaged D1 or generalized to all D1, we developed a genetic system involving simultaneous dual expression of wild type and mutant versions of D1 protein. Dual D1 strains (nS345P:eWT and nD170A:eWT) expressed a wild type (WT) D1 from ectopic and a damage prone mutant (D1-S345P, D1-D170A) from native locus on the chromosome. Characterization of strains showed that all dual D1 strains restore WT like phenotype with high PSII activity. Higher PSII activity indicates increased population of PSII reaction centers with WT D1. Analysis of steady state levels of D1 in nS345P:eWT by immunoblot showed an accumulation of WT D1 only. But, in vivo pulse labeling confirmed the synthesis of both S345P (exists as iD1) and WT D1 in the dual strain. Expression of nS345P:eWT in FtsH2 knockout background showed accumulation of both iD1 and D1 proteins. This demonstrates that dual D1 strains express both forms of D1, yet only damage prone PSII complexes are selected for repair providing evidence that the D1 degradation process is targeted towards damaged PSII complexes. Since the N-terminus has been previously shown to be important for the degradation of damaged D1, the possibility that the highly conserved cysteine 18 residue situated in the N-terminal domain of D1 is involved in the targeted repair process was tested by examining site directed mutants of this and the other cysteines of the D1 protein. This article is part of a Special Issue entitled: Photosynthesis Research for Sustainability: Keys to Produce Clean Energy.  相似文献   

18.
Thyroid hormone activation is catalyzed by two deiodinases, D1 and D2. Whereas D1 is a stable plasma membrane protein, D2 is resident in the endoplasmic reticulum (ER) and has a 20-min half-life due to selective ubiquitination and proteasomal degradation. Here we have shown that stable retention explains D2 residency in the ER, a mechanism that is nevertheless over-ridden by fusion to the long-lived plasma membrane protein, sodium-iodine symporter. Fusion to D2, but not D1, dramatically shortened sodium-iodine symporter half-life through a mechanism dependent on an 18-amino acid D2-specific instability loop. Similarly, the D2-specific loop-mediated protein destabilization was also observed after D2, but not D1, was fused to the stable ER resident protein SEC62. This indicates that the instability loop in D2, but not its subcellular localization, is the key determinant of D2 susceptibility to ubiquitination and rapid turnover rate. Our data also show that the 6 N-terminal amino acids, but not the 12 C-terminal ones, are the ones required for D2 recognition by WSB-1.  相似文献   

19.
Seasonal life cycles and resource uses of flower- and fruit-feeding drosophilids (Diptera: Drosophilidae) were studied from low to high altitudes in central Japan to understand their adaptation to seasonal changes of environmental conditions. Drosophila unipectinata and D. oshimai specialized to flowers, D. suzukii and D. subpulchrella depended almost on fruits, while D. lutescens , D. rufa , D. auraria , D. biauraria and D. sternopleuralis used both of them. It was assumed that D. unipectinata moved from low to high altitudes in June while D. oshimai , D. suzukii and D. subpulchrella in July. Migration of D. unipectinata is considered as a means to avoid summer heat or exploit early-summer resources at high altitudes. On the other hand, D. oshimai , D. suzukii and D. subpulchrella have the capacity to pass the summer at low altitudes, and therefore their migration is assumed as a means to escape from resource-poor conditions in summer at low altitudes or exploit resources at high altitudes. The generalist species, D. lutescens , D. rufa , D. auraria , D. biauraria and D. sternopleuralis , would not perform such extensive movements between low and high altitudes. They may pass the summer at low or mid altitudes depending on accidentally fallen immature fruits and/or some other resources such as decayed leaves.  相似文献   

20.
D(1)-like receptors have been reported to decrease oxidative stress in vascular smooth muscle cells by decreasing phospholipase D (PLD) activity. However, the PLD isoform regulated by D(1)-like receptors (D(1) or D(5)) and whether abnormal regulation of PLD by D(1)-like receptors plays a role in the pathogenesis of hypertension are unknown. The hypothesis that the D(5) receptor is the D(1)-like receptor that inhibits PLD activity and serves to regulate blood pressure was tested using D(5) receptor mutant mice (D(5)(-/-)). We found that in the mouse kidney, PLD2, like the D(5) receptor, is mainly expressed in renal brush-border membranes, whereas PLD1 is mainly expressed in renal vessels with faint staining in brush-border membranes and collecting ducts. Total renal PLD activity is increased in D(5)(-/-) mice relative to congenic D(5) wild-type (D(5)(+/+)) mice. PLD2, but not PLD1, expression is greater in D(5)(-/-) than in D(5)(+/+) mice. The D(5) receptor agonist fenoldopam decreases PLD2, but not PLD1, expression and activity in human embryonic kidney-293 cells heterologously expressing the human D(5) receptor, effects that are blocked by the D(5) receptor antagonist SCH-23390. These studies show that the D(5) receptor regulates PLD2 activity and expression. The hypertension in the D(5)(-/-) mice is associated with increased PLD expression and activity. Impaired D(5) receptor regulation of PLD2 may play a role in the pathogenesis of hypertension.  相似文献   

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