茵陈水提液的体外抗氧化活性

在．ＯＨ、Ｏ２和Ｈ２Ｏ２的产生和检测系统以及兔脑和肝组织匀浆中,加入一定量的茵陈（Ａｒｔｉｍｉｓｉａ ｃａｐｉｌｌａｒｉｓ Ｔｈｕｎｂ）,水提液,观察其与活性氧引发反应的竞争效应。结果表明,茵陈水提液降低．ＯＨ作用下的水杨酸羟基化作用及Ｏ２介导的氮兰四唑（ＮＢＴ）光化学还原,而对Ｈ２Ｏ２驱动的过氧化物－１太复合物的形成没有影响;显著抑制兔脑和肝组织匀浆的脂质过氧化作用。提示茵陈水提液具有显著的抗尖     

甘蓝型油菜和芥菜型油菜种间杂交研究

甘蓝型油菜与芥菜型油菜杂交研究结果表明,杂交结实力与杂交组合方式以及参与杂交的亲本材料有关,以芥菜型油菜作母本的杂交结实力高于以甘蓝型作母本的组合：芥×甘杂交组合的平均结实数／花为 ２．６４ 粒,而甘×芥杂交组合的平均结实数／花为 ０．１０ 粒。芥甘杂种一代形态特征和生育期介于双亲之间,甘芥杂种一代不表现整齐的中间类型,株间差异明显;总体来看,芥甘杂种一代与双亲回交的结实力（０．４０,０．２１）低于甘芥杂种一代与双亲回交的结实力（３．３０,１．７４）,无论是芥甘杂种一代还是甘芥杂种一代,用甘蓝型油菜作父本回交的结实力高于用芥菜型油菜作父本回交的结实力,但也有个别回交组合出现例外,不表现上述规律。 Ｂ Ｃ１ 代种子当年播种出苗率低（１８．５％ ）,群体株间性状差异明显,生育期极不一致。芥甘杂种一代与甘蓝型油菜亲本第二次回交,其平均结实数／花较回交一代提高 １．０８ 粒, Ｂ Ｃ２ 代种子当年播种出苗率仍较低,但较对应的 Ｂ Ｃ１ 代稍有提高,群体中出现趋回交父本性状但雄性育性彻底退化的植株。芥甘杂种一代自由授粉所得 Ｆ２ 群体是一个变异极为丰富的遗传群体。     

High-Activity Barley \bold\ralpha-Amylase by Directed Evolution

Barley -amylase isozyme 2 was cloned into and constitutively secreted by Saccharomyces cervisiae. The gene coding for the wild-type enzyme was subjected to directed evolution. Libraries of mutants were screened by halo formation on starch agar plates, followed by high-throughput liquid assay using dye-labeled starch as the substrate. The concentration of recombinant enzyme in the culture supernatant was determined by immunodetection, and used for the calculation of specific activity. After three rounds of directed evolution, one mutant (Mu322) showed 1000 times the total activity and 20 times the specific activity of the wild-type enzyme produced by the same yeast expression system. Comparison of the amino acid sequence of this mutant with the wild type revealed five substitutions: Q44H, R303K and F325Y in domain A, and T94A and R128Q in domain B. Two of these mutations, Q44H and R303K, result in amino acids highly conserved in cereal -amylases. R303K and F325Y are located in the raw starch-binding fragment of the enzyme molecule.     

Coupling of secondary active transport with\Delta \tilde \mu _{H^ + }

Most nutrients and ions in bacteria, yeasts, algae, and plants are transported uphill at the expense of a gradient of the electrochemical potential of protons deltamu-H+ (a type of secondary active transport). Diagnosis of such transports rests on the determination of the transmembrane electrical potential difference deltapsi and the difference of pH at the two membrane sides. The behavior of kinetic parameters K(T) (the half-saturation constant) and J(max), (the maximum rate of transport) upon changing driving ion concentrations and electrical potentials may be used to determine the molecular details of the transport reaction. Equilibrium accumulation ratios of driven solutes are expected to be in agreement with the deltapsi and deltapH measured independently, as well as with the Haldane-type expression involving K(T) and J(max). Different stoichiometries of H+/solute, as well as intramembrane effects of pH and deltapsi, may account for some of the observed inconsistencies.     

PCR扩增泥鳅和大鳞副泥鳅SRY盒基因

以特异扩增人ＳＲＹ基因保守区的一对引物,研究了泥鳅和大鳞副泥鳅基因组中ＳＲＹ盒基因的扩增。结果表明,该引物可以在泥鳅中扩增出四条带,其长度分别为２００,５５０、９４０和１０００ｂｐ。在大鳞副泥鳞中扩增出三条带,大小为２００,５５０和９００ｂｐ。经Ｓｏｕｔｈｅｒｎ杂交显示出二者的阳性带为２００和５５０ｂｐ。阳性带在雌雄个体间和两个物种间无差异。     

苜蓿中华根瘤菌与耐盐有关的DNA片段的克隆

以耐盐的苜蓿中华根瘤菌(\%Sinorhizobium meliloti) \%042B为材料,制备其总DNA,经过限制性内切酶\%Eco\%RⅠ的部分酶解,利用电洗脱方法回收15～25kb大小的DNA片段。以碱法制备载体质粒pLAFRⅠ,用\%Eco\%RⅠ将其切成线状,然后用T\-4DNA连接酶将回收片段与线状载体连接,利用包装蛋白进行包装后,感染大肠杆菌(Escherichia coli)S17\|1,构建了042B的基因文库。以固体亚硝基胍作为诱变剂处理出发菌株,在05mol/LNaCl的条件下,从2000个菌落中筛选得到12株042B的盐敏感突变株,以其中稳定的盐敏突变株GZ17为受体菌,利用两亲本杂交将含有042B的DNA片段的pLAFRⅠ重组质粒转移到GZ17中,在含有四环素和05mol/LNaCl的基本培养基上筛选出能够耐盐的阳性克隆,获得了与耐盐有关的7kb长的DNA片段。对该片段进行亚克隆,最终获得了4kb与耐盐有关的片段。     

矮生龙船花的组织培养和快速繁殖

矮生龙船花(IxoracoccineaL.)的带节茎段在MS 2,4D2.0mg/L培养基上产生大量的愈伤组织;在MS 6BA1.0mg/L NAA0.2mg/L培养基上芽的增殖系数达413,并产生少量的愈伤组织;在MS NAA0.2～2.0mg/L培养基上只产生芽而无愈伤组织形成。愈伤组织在MS 6BA0.5mg/L NAA0.5mg/L培养基上产生大量的不定芽,丛生芽在MS 6BA0.5mg/L NAA0.5mg/L培养基上生长较快并产生较多分枝,将分枝节下或切成段后在MS 6BA0.5mg/L NAA0.5mg/L培养基上能迅速生长并产生新的分枝。试管内小苗在1/2MS NAA0.5mg/L培养基上的生根壮苗效果较好。矮生龙船花试管苗成活率为935%。     

白豆杉细胞培养

紫杉醇是从短叶红豆杉〔Ｔａｘｕｓｂｒｅｖｉｆｏｌｉａ(Ｃｈｅｎｇ)Ｃｈｅｎｇ〕树皮中分离出来的二萜类生物碱[1],现已成为知名抗癌药物。紫杉醇主要来源于红豆杉属植物。白豆杉〔Ｐｓｅｕｄｏｔａｘｕｓｃｈｉｅｎｉｉ(Ｃｈｅｎｇ)Ｃｈｅｎｇ〕属红豆杉科白豆杉属,为...     

黑大蒜提取物联合抗生素对金黄色葡萄球菌和肠埃希菌的体外抗菌作用研究

评价黑大蒜提取物分别与头孢唑林或庆大霉素联合应用,对金黄色葡萄球菌和大肠埃希菌的体外抗菌效应。采用液体稀释法分别测定黑大蒜提取物对金黄色葡萄球菌和大肠埃希菌的最低抑菌浓度（MIC）。采用棋盘法设计,微量肉汤稀释法测定黑大蒜提取物联合头孢唑林或庆大霉素对金黄色葡萄球菌和大肠埃希菌的MIC,并计算部分抑菌浓度（FIC指数）。测定黑大蒜提取物对金黄色葡萄球菌和大肠埃希菌的时间-杀菌曲线。黑大蒜提取物对金黄色葡萄球菌的MIC为256μg/mL,黑大蒜提取物对大肠埃希菌的MIC为256μg/mL。时间-杀菌曲线结果显示黑大蒜提取物对金黄色葡萄球菌和大肠埃希菌的抑菌作用呈现较强的浓度依赖性。黑大蒜提取物联合头孢唑林后对金黄色葡萄球菌的FIC指数为0.75;黑大蒜提取物联合庆大霉素后对大肠埃希菌的FIC指数为0.5。黑大蒜提取物与头孢唑林或庆大霉素联合用药,可明显降低抗生素对金黄色葡萄球菌和大肠埃希菌的MIC,表现为相加和协同效应。     

美国蓝浆果的引种

１９８８年由美国引入１２个兔眼蓝浆果（ＶａｃｉｎｉｕｍａｓｈｅｉＲｅａｄｅ）品种,在江苏南京和溧水两地试种。１０年来生长结果正常,产量和品质与原产地无显著差异,引种获得成功,证明兔眼蓝浆果能适应本地区自然条件。单株产量平均７．５１ｋｇ,品种间差异显著,最高９．８６ｋｇ,最低１３４ｋｇ。单位投影面积产量３．１０ｋｇ／ｍ２,最高４．０６ｋｇ／ｍ２,最低１．１３ｋｇ／ｍ２。高于或至少不低于原产区产量记录。据此预测,栽植距离适宜时,在本地区亩产量可达１５００～２０００ｋｇ以上。大多数品种果实糖酸比很高,鲜食风味好,氨基酸含量中等,矿质元素Ｚｎ和Ｓｅ含量高。兔眼蓝浆果可在江苏南部丘陵地区发展;此外,还应将试验扩大到南方红黄壤地区;并对本国野生资源开展研究和利用。     

Estimation of ^{3}J_{HN\hbox{-}H\alpha} and ^{3}J_{H\alpha\hbox{-}H\beta} coupling constants from heteronuclear TOCSY spectra

(3)J proton-proton coupling constants bear information on the intervening dihedral angles. Methods have been developed to derive this information from NMR spectra of proteins. Using series expansion of the time dependent density matrix, and exploiting the simple topology of amino acid spin-systems, formulae for estimation of (3)J(HN-Halpha) and (3)J(Halpha-Hbeta) from HSQC-TOCSY spectra are derived. The results obtained on a protein entailing both alpha-helix and beta-sheet secondary structure elements agree very well with J-coupling constants computed from the X-ray structure. The method compares well with existing methods and requires only 2D spectra which would be typically otherwise recorded for structural studies.     

胡萝卜var sativus Hoffm Deutschl抗冻 蛋白基因的克隆及测序

以宁夏吴忠胡萝卜、陕西华县胡萝卜、陕西汉中胡萝卜3个地方品种为材料,用PCR方法克隆了中国胡萝卜var\%sativus\%HoffmDeutschl的抗冻蛋白基因\%afp\%,测定了宁夏吴忠胡萝卜\%afp\%的核苷酸序列,和英国胡萝卜var\%autumn\%King\%afp\%序列对比,在所测1004个核苷酸中,有35个碱基不同,其中无义突变20个,有义突变15个。按有义突变计,同源性为\{98.5%\}     

Eiwei\kristalloide in Parenchymzell-Plastiden vonMusa

Zusammenfassung Die Piastiden des leitbündelnahen Parenchyms sehr junger BananenblÄtter enthalten neben StÄrke, Prolamellarkörpern und Thylakoiden in ihrem Stroma bis zu l gro\e Eiwei\-kristalloide, die einen regelmÄ\igen Feinbau aus filamentartig angeordneten 50–60 å weiten Untereinheiten erkennen lassen. Die Kristalloide sind von einer Hülle umgeben, die hÄufig mit dichten Thylakoidstapeln in Verbindung steht.

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Protein crystalloids in plastids ofMusa parenchyma cells

Summary In very young banana leaves plastids of the parenchyma cells near the vascular bundles contain about 1 large crystalloids in their stroma, besides starch, prolamellar bodies and thylacoids. The crystalloids have a very regular fine structure consisting of 50–60 å filament-like subunits and are surrounded by a membranous envelope that often is in contact with stacks of thylacoids. Form and array of the crystalloid subunits are finally compared with protein-crystalloids inPhaseolus plastids, intramitochondrial crystals and crystal-containing bodies.

     

Evidence that the intrinsic membrance protein LHCII in thylakoids is necessary for maintaining localized\Delta \tilde \mu _{H^ + } energy coupling

This work tested the hypothesis that thylakoid localized proton-binding domains, suggested to be involved in localized -driven ATP formation, are maintained with the involvement of several membrane proteins, including the LHCII (Laszlo, J. A., Baker, G. M., and Dilley, R. A. (1984) Biochim. Biophys. Acta 764, 160–169), which comprises about 50% of the total thylakoid protein. The concept we have in mind is that several membrane proteins cooperate to shield a localized proton diffusion pathway from direct contact with the lumen, thus providing a physical barrier to H⁺ equilibration between the sequestered domains and the lumen. A barely mutant,chlorina f ₂, that lacks Chl b and does not accumulate some of the LHCII proteins, was tested for its capacity to carry out localized-proton gradient-dependent ATP formation. Two previously developed assays permit clear discrimination between localized and delocalized gradient-driven ATP formation. Those assays include the effect of a permeable buffer, pyridine, on the number of single-turnover flashes needed to reach the energetic threshold for ATP formation and the more recently developed assay for lumen pH using 8-hydroxy-1,3,6-pyrene trisulfonic acid as a lumenally loaded pH-sensitive fluorescent probe. By those two criteria, the wild-type barley thylakoids revealed either a localized or a delocalized energy coupling mode under low- or high-salt storage conditions, respectively. Addition of Ca⁺⁺ to the high-salt storage medium caused those thylakoids to maintain a localized energy-coupling response, as previously observed for pea thylakoids. In contrast, thechlorina f ₂ mutant thylakoids had an active delocalized energy coupling activity but did not show localized energy coupling under any conditions, and added Ca⁺⁺ to the thylakoid storage medium did not alter the delocalized energy coupling mode. One interpretation of the results is that the absence of the LHCII polypeptides produces a leaky pathway for protons which allows the gradient to equilibrate with the lumen under all conditions. Another interpretation is possible but seems less likely, that being that the absence of the LHCII polypeptides in some way causes the proposed Ca⁺⁺ -gated H⁺ flux site on the membrane sector (CF₀) of the energy coupling complex to lose its gating function.     

Modulation of the cAMP Response by G\alpha _i and G\beta \gamma : A Computational Study of G Protein Signaling in Immune Cells

Cyclic AMP is important for the resolution of inflammation, as it promotes anti-inflammatory signaling in several immune cell lines. In this paper, we present an immune cell specific model of the cAMP signaling cascade, paying close attention to the specific isoforms of adenylyl cyclase (AC) and phosphodiesterase that control cAMP production and degradation, respectively, in these cells. The model describes the role that G protein subunits, including G \(\alpha _s\) , G \(\alpha _i\) , and G \(\beta \gamma \) , have in regulating cAMP production. Previously, G \(\alpha _i\) activation has been shown to increase the level of cAMP in certain immune cell types. This increase in cAMP is thought to be mediated by \(\beta \gamma \) subunits which are released upon G \(\alpha \) activation and can directly stimulate specific isoforms of AC. We conduct numerical experiments in order to explore the mechanisms through which G \(\alpha _i\) activation can increase cAMP production. An important conclusion of our analysis is that the relative abundance of different G protein subunits is an essential determinant of the cAMP profile in immune cells. In particular, our model predicts that limited availability of \(\beta \gamma \) subunits may both \((i)\) enable immune cells to link inflammatory G \(\alpha _i\) signaling to anti-inflammatory cAMP production thereby creating a balanced immune response to stimulation with low concentrations of PGE2, and \((ii)\) prohibit robust anti-inflammatory cAMP signaling in response to stimulation with high concentrations of PGE2.     

稻绿核菌中绿色素的提取及其应用

稻绿核菌〔Ｕｓｔｉｌａｇｉｎｏｉｄｅａｖｉｒｅｎｓ(Ｃｋｅ.)Ｔａｋ.〕又名稻曲拟黑粉菌[1],其子实体即为中药的粳谷奴,治走马喉痹[2],ＳｈｉｂａｔａＳ.报道稻绿核含有稻核黑粉菌素(ｕｓｔｉｌａｇｉｎｏｉｄｉｎｓ)[3]。ＹａｂｕｔａＴ.ａｎｄＳｕｍｉｋｉＹ.检测证?..     

中国弗叶甲属四新种记述(鞘翅目:叶甲科:叶甲亚科)

记述弗叶甲属Phratora4新种,即陈氏弗叶甲Phratora cheni sp.nov.,紫翅弗叶甲P.purpurea.sp.nov.,双钩弗叶甲P.biuncinata sp.nov.,皱弗叶甲P.caperata sp.nov.,模式标本保存在中国科学院动物研究所。     

Rhabdoide fehlen den Schlie\zellen vonDrosera

Zusammenfassung WÄhrend die Epidermiszellen der KelchblÄtter vonDrosera Rhabdoide (Eiwei\spindeln) enthalten, fehlen diese den Schlie\zellen.