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1.
张延滨  祁适雨 《植物研究》1996,16(1):118-121
以前的SDS-PAGE分析表明龙麦15在Glu-D1位点的高分子量(HMW)麦谷蛋白亚基为2+12。我们通过对龙麦15进行大量的SDS-PAGE分析,发现了Glu-D1位点的HMW麦谷蛋白亚基为5+10的龙麦15生物型。文章分析了5+10龙麦15生物型的产生,利用及对当前优质麦育种工作的理论和实践意义。  相似文献   

2.
为了探讨凝集素在豆科植物与根瘤菌的识别过程中的作用,用DEAE-32离子交换层析和SephadexG-150凝胶过滤分离、纯化格拉姆柱花草种子凝集素(SGL),其分子量约为45kD,由两个相同的亚基组成,等电点约pH5.8,它是一种糖蛋白,含糖量约为2.6%.SGL的热稳定性强.SGL的血凝活性能被甘露糖所抑制.SGL对红细胞的凝集作用可能具有种属专一性;SGL具有强的促有丝分裂作用;荧光标记实验显示:9株能与格拉姆柱花草植株结瘤的菌株有7株能与SGL结合,6株不能与之结瘤的菌株,只有1株能与SGL结合,这表明不同根瘤菌菌株对SGL的结合能力,和它们在格拉姆柱花草上结瘤能力之间可能具有一定的生物学相关性.  相似文献   

3.
三色缘龙血 树(Dracaena co- ncinna cv.Tri- Color),又称三色细叶千年木、彩虹龙血树、彩虹竹蕉、彩纹竹蕉等,是百合科(或龙舌兰科)龙血树属的常绿木本植物。它的茎干挺拔,直径0.5—4厘米,高可达3米以上。叶无柄,叶片剑形常多枚簇生于茎顶,长l0—60厘米,宽0.5—2厘米。叶片边缘具红色条纹,有时兼有黄白色条纹,在光线较强的条件下,叶片背面会形成多条红色条纹。叶片脱落时,在茎干上由叶痕围成明显的鳞片状图案,看上去就象“龙”体表覆盖的鳞甲。三色缘龙血树叶片色彩艳丽,细长飘逸,犹  相似文献   

4.
贵州灵芝科IV.   总被引:1,自引:0,他引:1  
何绍昌  连宾 《真菌学报》1995,14(2):104-106
本文报道贵州灵芝科灵芝属2种,1.多分枝灵芝Ganoderma ramosissimum Zhao;2.任氏灵芝Ganoderma renii He,sp.nov.上述研究标本保藏在贵州科学院生物研究所真菌标本室(HMBAG)。  相似文献   

5.
与圈卷产色链霉菌分化有关的一个新基因—sawD的研究   总被引:1,自引:0,他引:1  
距链霉菌发育分化控制启动子 P T H4 直接控制的下游基因 pro X 间隔24 个碱基处存在一个部分开放阅读框 ( O R F) , 根据序列分析推测为丝氨酸蛋白酶的一部分。以此部分 D N A 序列为探针, 在构建的圈卷产色链霉菌7100 的 D N A 文库中克隆到一个与链霉菌发育和分化有关的新基因, 称之为sa w D。序列测定及分析结果表明, 在1320bp 的 D N A 序列中有一个完整的开放阅读框 ( O R F) , 翻译起始位点为210 位碱基处的 G T G, 终止密码子 T G A 位于序列的999 位碱基处。在距翻译起始位点 G T G 上游4 个碱基间隔处有典型的核糖体结合位点区域 G A G G G A。在计算机蛋白文库中进行了同源性比较研究, 结果表明263个氨基酸的蛋白产物与 Caulobacter crescentus 的依赖于 A T P 的丝氨酸蛋白酶有447 % 的同源性, 其中存在功能活性区的丝氨酸保守位点 ( G P S A G) 。基因功能研究表明, saw D 在圈卷产色链霉菌发育分化中与气生菌丝分隔和色素的合成有关。该基因被阻断或破坏后, 使野生型圈卷产色链霉菌的分化停止在气生菌丝阶段, 不能形成具有灰色色素的孢子, 而出现白色  相似文献   

6.
报道了采自新疆地区的百花丹科、龙胆科、紫草科的4 个中国新记录种———塔尔巴哈台彩花( Acantholimontarbagataicum Gamajun) 、西亚龙胆( Gentiana septemfida Pallas) 、早春龙胆( G.verna L.subsp. pontica M. Soltokovic) Hayek 、塔城滨紫草( Mertensia tarbagataica B.Fedtsch .) 。  相似文献   

7.
以前的SDS-PAGE分析表明龙麦15在Glu-D1位点的高分子量(HMW)麦谷蛋白亚基为2+12。我们通过对龙麦15进行大量的SDS-PAGE分析,发现了Glu-D1位点的HMW麦谷蛋白亚基为5+10的龙麦15生物型。文章分析了5+10龙麦15生物型的产生,利用及对当前优质麦育种工作的理论和实践意义。  相似文献   

8.
罢生植物根转的丛枝菌根真菌Ⅱ.   总被引:4,自引:1,他引:3  
盖京苹  刘润进 《菌物系统》2000,19(2):205-211
本文主要报道了野生植物根围Glomus属的17个种,聚球囊霉G.aggregatum Schench&Smith。苏格兰球囊霉G.caledonium(Nicol.&Gerd.)Trappe&Gerd,近明球囊霉G.claroidueumSchenck&Smith,明球囊霉G.CLARUM nICOLSON&Schenck,缩球囊霉G.constrictum Trappe,透光球囊霉G.fasc  相似文献   

9.
促性腺激素释放激素的种类,作用及调节   总被引:3,自引:0,他引:3  
促性腺激素释放激素的种类、作用及调节禹龙香李远友(湖南农业大学医院,长沙410128)(中山大学生物系,广州510275)促性腺激素释放激素(GnRH)是由脊椎动物的脑(主要是视前—下丘脑)产生的一类十肽激素,它在脑垂体促性腺激素(GtH)的合成和分...  相似文献   

10.
经DEAE-Sephacel、UltrogelAcA 34、Heptylam ine-Sepharose 和Bio Scale Q2等四步层析从牛脑皮层膜中同时纯化出抑制型G 蛋白(inhibitory G protein, Gi)和O型G蛋白(other G pro-tein, Go).对Go 的选择性激活使Gi 和Go 的分离大为简化,并使二者的大量制备成为可能.纯化的G 蛋白的SDS-PAGE银染显示单一蛋白带,其结合[35S]GTPγS的活性分别提高68倍和124倍.用圆二色光谱法(CD)测量了纯化的G蛋白的二级结构.  相似文献   

11.
中国西藏聂拉木色龙西山二叠系—下三叠统牙形刺   总被引:11,自引:0,他引:11  
本文详细描述了西藏聂拉木色龙西山二叠系—下三叠统牙形刺共7属20种;组建了自下而上的7个牙形刺带:Hindeodusparvus,Clarkinacarinata,Neospathoduskummeli,N,cristagalli,N.pakistanensis,N.waageni,Neogondolellajubata-Neospathodustriangularis带;发现了这些牙形刺带与菊石带的对比关系。色龙西山剖面缺失二叠系顶部的层位,由于色龙群顶部产Mesogondolellaidahoensis,M.phosphoriensis和M.spp.等牙形刺,其时代可能为栖霞晚期至茅口早期,考虑到再沉积的可能性,其时代也不会晚于吴家坪期。下三叠统发育较完整,特别是底部,但是由于再沉积或凝缩的原因,在三叠系底部常有二叠系的牙形刺出现或出现混合动物群。本文讨论了二叠-三叠系界线,并把菊石Otoceraslatilobatum带和牙形刺Hindeodusparvus带之底作为三叠系之底界。  相似文献   

12.
近30年来,巴基斯坦盐岭地区的Wargal组和Chhidru组以及在喜马拉雅地区相当地层的地质时代被许多学者视为中二叠世(瓜达鲁普世)。根据华南与盐岭地区瓜达鲁普统和乐平统的牙形类化石带对比,可以确定Amb组和Wargal组底部的时代为瓜达鲁普世晚期,瓜达鲁普统与乐平统的界线位于Wargal组下部,吴家坪阶与长兴阶的界线位于Chhidru组的下部,而二叠与三叠系的界线位于Mianwali组下部的Kathwai段之内。我国西藏南部色龙群及相当地层含有与巴基斯坦盐岭地区Kalabagh段和Chhidru组可对比的乐平世腕足动物群以及二叠系—三叠系界线附近连续的牙形类化石带,由此可以推定色龙群的时代应为乐平世。  相似文献   

13.
We report 20 new species records for the Coleoptera fauna in New Brunswick, Canada, five of which are new records for the Maritime provinces, including one species that is new for Canada. One species of Kateretidae, Kateretes pusillus (Thunberg) is newly recorded for New Brunswick and the Maritime provinces. Stelidota octomaculata (Say), Phenolia grossa (Fabricius), andCryptarcha strigatula Parsons of the family Nitidulidae are added to the faunal list of New Brunswick; the latter species is new to the Maritime provinces. Two species of Cerylonidae, Philothermus glabriculus LeConte and Cerylon unicolor (Ziegler), are reported for the first time for New Brunswick. Philothermus glabriculus is new for the Maritime provinces. Two species of Endomychidae, Hadromychus chandleri Bousquet and Leschen and Danae testacea (Ziegler) are newly recorded for New Brunswick. Three species of Coccinelidae, Stethorus punctum punctum (LeConte), Naemia seriata seriata Melsheimer, and Macronaemia episcopalis (Kirby) are added to the provincial list. Macronaemia episcopalis (Kirby) is a species new to the Maritime provinces. Nine species of Latridiidae, Cartodere nodifer (Westwood), Dienerella ruficollis (Marsham), Enicmus aterrimus Motschulsky, Enicmus fictus Fall, Encimus histrio Jay and Tomlin, Lathridius minutus (Linnaeus), Stephostethus productus Rosenhauer, Corticaria elongata (Gyllenhal), and Corticarina longipennis (LeConte) are newly recorded for New Brunswick. Stephostehus productus is newly recorded from Canada. Collection and habitat data are presented for all these species.  相似文献   

14.
Nodes in networks are often of different types, and in this sense networks are differentiated. Here we examine the relationship between network differentiation and network size in networks under economic or natural selective pressure, such as electronic circuits (networks of electronic components), Legos (networks of Lego pieces), businesses (networks of employees), universities (networks of faculty), organisms (networks of cells), ant colonies (networks of ants), and nervous systems (networks of neurons). For each of these we find that (i) differentiation increases with network size, and (ii) the relationship is consistent with a power law. These results are explained by a hypothesis that, because nodes are costly to build and maintain in such "selected networks", network size is optimized, and from this the power-law relationship may be derived. The scaling exponent depends on the particular kind of network, and is determined by the degree to which nodes are used in a combinatorial fashion to carry out network-level functions. We find that networks under natural selection (organisms, ant colonies, and nervous systems) have much higher combinatorial abilities than the networks for which human ingenuity is involved (electronic circuits, Legos, businesses, and universities). A distinct but related optimization hypothesis may be used to explain scaling of differentiation in competitive networks (networks where the nodes themselves, rather than the entire network, are under selective pressure) such as ecosystems (networks of organisms).  相似文献   

15.
The inhibition of five human carbonic anhydrase (hCA, EC 4.2.1.1) isozymes; the cytosolic hCA I and II, the membrane-bound hCA IV, the mitochondrial hCA V, and the tumor-associated, transmembrane hCA IX, with anions isosteric and isoelectronic with sulfate, nitrate, and carbonate; such as chlorate, perchlorate, bromate, iodate, periodate, silicate, bismuthate, vanadate, molybdate, and wolframate is reported. Apparently, the geometry of the inhibitor (tetrahedral or trigonal) does not influence its binding to the Zn(II) ion of the enzyme active site, but the nature of the central element is the most important factor influencing potency. Isozymes hCA I and II are best inhibited by chlorate, perchlorate, and silicate, together with the anions structurally related to sulfate, sulfamate, and sulfamidate, but sulfate itself is a weak inhibitor (inhibition constant of 74 mM against hCA I and 183 mM against hCA II). Molybdate is a very weak hCA I inhibitor (K(I) of 914 mM) but it interacts with hCA II (K(I) of 27.5mM). Isozyme IV is well inhibited by sulfate (K(I) of 9 mM), sulfamate, and sulfamidate (in the low micromolar range), but not by perchlorate (K(I) of 767 mM). The mitochondrial isozyme V has the lowest affinity for sulfate (K(I) of 680 mM) and carbonate (K(I) of 95 mM) among all the investigated isozymes, suggesting on one hand its possible participation in metabolon(s) with sulfate anion exchanger(s), and on the other hand an evolutionary adaptation to working at higher pH values (around 8.5 in mitochondria) where rather high amounts of carbonate in equilibrium with bicarbonate may be present. Metasilicate, isosteric to carbonate, is also about a 10 times weaker inhibitor of this isozyme as compared to other CAs investigated here (K(I) of 28.2 mM). Surprisingly, the tumor-associated isozyme IX is resistant to sulfate inhibition (K(I) of 154 mM) but has affinity in the low micromolar range for carbonate, sulfamate, and sulfamidate (K(I) in the range of 8.6-9.6 microM). This constitutes another proof that this isozyme best works at acidic pH values present in tumors, being inhibited substantially at higher pH values when more carbonate may be present. Bromate and chlorate are quite weak CA IX inhibitors (K(I) s of 147-274 mM).  相似文献   

16.
Caffeic acid phenethyl ester (CAPE) is an active component of honeybee propolis extracts. Carbonic anhydrases (CAs, EC 4.2.1.1) are widespread and intensively studied metalloenzymes present in higher vertebrates including humans as many diverse isoforms. Acetylcholinesterase (AChE) is responsible for acetyl choline (ACh) hydrolysis and plays a fundamental role in nerve impulse transmission by terminating the action of the ACh neurotransmitter at cholinergic synapses and neuromuscular junctions. Butyrylcholinesterase (BChE) is another enzyme abundantly present in the liver and released into blood in a soluble form. Lactoperoxidase (LPO) is an enzyme involved in fighting pathogenic microorganisms whereas glutathione S-transferases (GSTs) are dimeric proteins present both in prokaryotic and eukaryotic organisms and involved in cellular detoxification mechanisms. In the present study, the inhibition effect of CAPE on human carbonic anhydrase (hCA) isoforms I, II, IX, and XII, AChE, BChE, LPO, and GST was evaluated. CAPE inhibited these enzymes with Kis in the range between micromolar to picomolar. The best inhibitory effect was observed against AChE and BChE.  相似文献   

17.
Leucine-rich repeats (LRRs) with 20-30 amino acids in unit length are present in many proteins from prokaryotes to eukaryotes. The LRR-containing proteins include a family of nine small proteoglycans, forming three distinct subfamilies: class I contains biglycan/PG-I and decorin/PG-II; class II: lumican, fibromodulin, PRELP, keratocan, and osteoadherin; and class III: epiphycan/PG-Lb and osteoglycin or osteoinductive factor. Comparative sequence analysis of the 34 available protein sequences reveals that these proteoglycans have two types of LRRs, which we call S and T. The type S LRR is 21 residues long and has the consensus sequence of xxaPzxLPxxLxxLxLxxNxI. The type T LRR has 26 residues; its consensus sequence is zzxxaxxxxFxxaxxLxxLxLxxNxL. In both "x" indicates variable residue; "z" is frequently a gap; "a" is Val, Leu, or Ile; and I is Ile or Leu. These type S and TLRRs are ordered into two super-motifs--STT with about 73 residues in classes I and II and ST with about 47 residues in class III. The 12 LRRs in the small proteoglycans of I and II are best represented as (STT)4; the seven LRRs of class III as (ST)T(ST)2. Our analyses indicate that classes I/II and III evolved along different paths after the establishment of the precursor ST, and classes I and II also diverged after the establishment of the precursor (STT)4.  相似文献   

18.
Floral structure of all putative families of Crossosomatales as suggested by molecular studies was comparatively studied. The seven comprise Crossosomataceae, Stachyuraceae, Staphyleaceae, Aphloiaceae, Geissolomataceae, Ixerbaceae, and Strasburgeriaceae. The entire clade (1) is highly supported by floral structure, also the clades (in sequence of diminishing structural support): Ixerbaceae/Strasburgeriaceae (2), Geissolomataceae/Ixerbaceae/Strasburgeriaceae (3), Aphloiaceae/Geissolomataceae/Ixerbaceae/Strasburgeriaceae (4), and Crossosomataceae/Stachyuraceae/Staphyleaceae (5). Among the prominent floral features of Crossosomatales (1) are solitary flowers, presence of a floral cup, imbricate sepals with outermost smaller than inner, pollen grains with horizontally extended endoapertures, shortly stalked gynoecium, postgenitally united carpel tips forming a compitum, stigmatic papillae two‐ or more‐cellular, ovary locules tapering upwards, long integuments forming zigzag micropyles, cell clusters with bundles of long yellow crystals, mucilage cells, seeds with smooth, sclerified testa and without a differentiated tegmen. Clade (2) is characterized by large flowers, petals forming a tight, pointed cone in bud, stamens with long, stout filaments and sagittate anthers, streamlined, conical gynoecium, antitropous ovules, rudimentary aril, lignified, unicellular, T‐shaped hairs and idioblasts with striate mucilaginous cell walls. Clade (3) is characterized by alternisepalous carpels, punctiform stigma formed by postgenitally united and twisted carpel tips, synascidiate ovary, only one or two pendant ovules per carpel, nectary recesses between androecium and gynoecium. Clade (4) is characterized by pronounced ‘pollen buds’. Clade (5) is characterized by polygamous or functionally unisexual flowers, x‐shaped anthers, free and follicular carpels (not in Stachyuraceae). Crossosomataceae and Aphloiaceae, although not retrieved as a clade in molecular studies, share several special floral features: polystemonous androecium; basifixed anthers without a connective protrusion; stigma with two more or less decurrent crests; camplyotropous ovules and reniform seeds; simple, disc‐shaped nectaries and absence of hairs. © 2005 The Linnean Society of London, Botanical Journal of the Linnean Society, 2005, 147 , 1–46.  相似文献   

19.
Activation of protein kinase Cepsilon (PKCepsilon), opening of mitochondrial ATP-sensitive K(+) channels (mitoK(ATP)), and increased mitochondrial reactive oxygen species (ROS) are key events in the signaling that underlies cardioprotection. We showed previously that mitoK(ATP) is opened by activation of a mitochondrial PKCepsilon, designated PKCepsilon1, that is closely associated with mitoK(ATP). mitoK(ATP) opening then causes an increase in ROS production by complex I of the respiratory chain. This ROS activates a second pool of PKCepsilon, designated PKCepsilon2, which inhibits the mitochondrial permeability transition (MPT). In the present study, we measured mitoK(ATP)-dependent changes in mitochondrial matrix volume to further investigate the relationships among PKCepsilon, mitoK(ATP), ROS, and MPT. We present evidence that 1) mitoK(ATP) can be opened by H(2)O(2) and nitric oxide (NO) and that these effects are mediated by PKCepsilon1 and not by direct actions on mitoK(ATP), 2) superoxide has no effect on mitoK(ATP) opening, 3) exogenous H(2)O(2) or NO also inhibits MPT opening, and both compounds do so independently of mitoK(ATP) activity via activation of PKCepsilon2, 4) mitoK(ATP) opening induced by PKG, phorbol ester, or diazoxide is not mediated by ROS, and 5) mitoK(ATP)-generated ROS activates PKCepsilon1 and induces phosphorylation-dependent mitoK(ATP) opening in vitro and in vivo. Thus mitoK(ATP)-dependent mitoK(ATP) opening constitutes a positive feedback loop capable of maintaining the channel open after the stimulus is no longer present. This feedback pathway may be responsible for the lasting protective effect of preconditioning, colloquially known as the memory effect.  相似文献   

20.
We tested the hypothesis that the H2-based membrane biofilm reactor (MBfR) is capable of reducing multiple oxidized contaminants, a common situation for groundwater contamination. We conducted bench-scale experiments with three groundwater samples collected from California’s San Joaquin Valley and on two synthetic groundwaters containing selenate and chromate. The actual groundwater sources had nitrate levels exceeding 10 mg-N l−1 and different combinations of anthropogenic perchlorate + chlorate, arsenate, and dibromochloropropane (DBCP). For all actual groundwaters, the MBfR reduced nitrate to less than 0.01 mg-N l−1. Present in two groundwaters, perchlorate + chlorate was reduced to below the California Notification Level, 6 μg-ClO4 l−1. As(V) was substantially reduced to As(III) for two groundwaters samples, which had influent As(V) concentrations from 3 to 8.8 μg-As l−1. DBCP, present in one groundwater at 1.4 μg l−1, was reduced to below its detection limit of 0.01 μg l−1, which is well below California’s 0.2 μg l−1 MCL for DBCP. For the synthetic groundwaters, two MBfRs initially reduced Se(VI) or Cr(VI) stably to Se° or Cr(III). When we switched the influent oxidized contaminants, the new oxidized contaminant was reduced immediately, and its reduction soon was approximately the same or greater than it had been reduced in its original MBfR. These results support that the H2-based MBfR can reduce multiple oxidized contaminants simultaneously.  相似文献   

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