抑制玉米幼胚愈伤组织褐化的研究

褐化是植物组织培养中一种常见的问题,直接影响组织培养能否成功。为了控制植物组织培养中的褐化现象,选取‘丹黄25’、P138、H21 3个玉米自交系幼胚为外植体,着重探讨胚龄,2,4-D、甘露醇、L-脯氨酸和AgNO3浓度对玉米幼胚愈伤组织褐化的影响。结果表明,选取授粉11天的‘丹黄25’幼胚、13天的P138和H21幼胚接种到诱导培养基中,待长出愈伤后转移到添加2 mg/L 2,4-D、10 g/L甘露醇、10 mg/L L-脯氨酸、10 mg/L硝酸银的继代培养基上,愈伤组织褐化率显著降低,表明培养基的种类及添加物对愈伤组织的生长有重要影响。     

Synthesis and Characterization of Molybdenum Carbide Clusters MonC4n, (n = 1 to 4)

Laser radiation (XeCl laser, 308-nanometer wavelength) focused into a cell containing Mo(CO)(6) vapor produced ultrafine particles in the extended waist of the laser beam. Negative ion mass spectrometry revealed molybdenum carbide cluster ions with a stoichiometry MonC4n (n = 1 to 4). The MonC4n(-) (n = 2 to 4) ions are completely unreactive with NH(3), H(2)O, and O(2), suggesting structures in which the molybdenum atoms are unavailable for coordination to additional ligands. Collision-induced dissociation studies of these anions show the loss of MoC(4) units as the main fragmentation pathway. This observation, together with the lack of addition reactions, provides a basis for structures in which a planar cluster of two, three, or four molybdenum atoms is surrounded by, and bonded to, carbon dimers.     

Infrared signature of structures associated with the H+(H2O)n (n = 6 to 27) clusters

We report the OH stretching vibrational spectra of size-selected H+(H2O)n clusters through the region of the pronounced "magic number" at n = 21 in the cluster distribution. Sharp features are observed in the spectra and assigned to excitation of the dangling OH groups throughout the size range 6 相似文献   

陕南卷丹10个野生种群数量性状变异分析

为揭示陕南地区卷丹Lilium lancifolium野生种群的表型变异程度和规律, 以该区10个有代表性的卷丹野生种群, 每个种群30个个体为试材, 对其茎、叶、花的茎粗、叶片数、着花量等16个数量性状指标进行方差分析、相关性分析及聚类分析, 探讨种群间及种群内表型多样性的变异特点。结果表明:①卷丹数量性状在种群间和种群内均存在一定程度的变异, 不同性状的平均变异系数为2.07%(花丝长)~35.38%(着花量), 种群间的平均变异系数为7.52%(汉台区天台山乡种群)~17.18%(城固县石槽河乡种群)。②相关性分析表明, 着花量(r=0.684, P < 0.05, n=10), 外瓣宽长比(r=0.651, P < 0.05, n=10), 柱头宽(r=0.729, P < 0.05, n=10)与海拔高度有显著正相关性, 中部叶宽长比(r=-0.743, P < 0.05, n=10), 花丝长(r=-0.795, P < 0.01, n=10)与海拔高度有显著负相关性; 且茎秆高度(r=0.733, P < 0.01, n=10), 叶片数(r=0.718, P < 0.01, n=10), 着花量(r=0.752, P < 0.01, n=10)与生境有显著正相关性, 上部叶宽长比(r=-0.707, P < 0.05, n=10), 内瓣宽长比(r=-0.681, P < 0.05, n=10)与生境有显著负相关性; ③Q聚类分析显示, 陕南地区10个卷丹野生种群可以初步分为2组, 汉台区天台山乡种群单独为一组。     

东方粘虫中肠V-ATPase H亚基原核表达及纯化

对东方粘虫Mythimna separate(Walker)中肠V-ATPase H亚基基因(VATPH)进行克隆、原核表达及纯化。首先采用RT-PCR技术克隆基因,再构建原核表达载体(pET15b-VATPH)并转入E.coil BL21(DE3),经异丙基硫代-β-D-半乳糖苷(isopropyl-β-D-thiogalactoside,IPTG)诱导表达,用Ni-NTA柱及S-200分子筛纯化,最后进行SDS-PAGE分析。结果表明,pET15b-VATPH可高效表达V-ATPase H亚基,纯化后可获得单一条带且分子质量约为55ku的重组蛋白。该结果为进一步研究V-ATPase H亚基的晶体结构,药物小分子与H亚基大分子的相互作用,尤其是以H亚基为筛选模型创制新农药奠定基础。     

紫薇异倍体的杂交亲和性分析及子代倍性鉴定

以二倍体红薇(H,2n)、三倍体紫薇(Z,3n)、四倍体紫薇(Z,4n)及四倍体银薇(Y,4n)为试材,进行杂交试验,检测紫薇异倍体杂交的亲和性,并采用细胞学倍性鉴定法对杂交子代的倍性进行鉴定和比较。结果显示:不同杂交组合子代的结实特性以及种子的出苗率均存在差异,其中Z(4n)×H(2n)的单果重(0.22 g)、单果种子数(40.1)、千粒重(1.79 g)及出苗率(36.4%)均高于H(2n)×Y(4n),且差异达到显著水平,表明在二倍体与四倍体的杂交中,四倍体作为母本的亲和性更高;H(2n)×Z(3n)后代倍性主要为非整倍体,占80%以上,其次是2n,占11.8%;Y(4n)×H(2n)后代倍性主要为3n,占50%,其次是非整倍体,占40%;H(2n)×Z(3n)后代中,1株为3n,2株为非整倍体;Y(4n)×H(2n)后代中,6株为3n,3株为非整倍体;H(2n)×Y(4n)后代幼苗中,1株为2n,1株为3n;Z(4n)×Z(4n)后代中,1株为4n;在杂交组合H(2n)×Z(3n)、Y(4n)×H(2n)及H(2n)×Y(4n)后代中还出现三子叶变异的幼苗。     

Pyrrhotites: Stoichiometric Compounds with Composition Fen--1Sn (nge8)

A new type of natural pyrrhotite, orthorhombic 11C type (a = 6.892, b = 11.952, c = 5.744 x 11 angstroms), and the hexagonal 6C type (a = 6.89, c = 5.76 x 6 angstroms) are described. Their compositions are Fe(10)S(11) and Fe(11)S(12), respectively. Pyrrhotites stable in nature have essentially stoichiometric composition, Fe(n)-(l)S(n) (n>/=8), with the structures of n/2C type for n even and of nC type for n odd. The solid solutions between Fe(11)S(12) and Fe(10)S(11), and between Fe(10)S(11) and Fe(9)S(10) are considered metastable in nature.     

Size-Specific Infrared Spectra of Benzene-(H2O)n Clusters (n = 1 through 7): Evidence for Noncyclic (H2O)n Structures

Resonant ion-dip infrared spectroscopy has been used to record size-specific infrared spectra of C(6)H(6)-(H(2)O)n clusters with n = 1 through 7 in the O-H stretch region. The O-H stretch spectra show a dramatic dependence on cluster size. For the n = 3 to 5 clusters, the transitions can be divided into three types-attributable to free, pi hydrogen-bonded, and single donor water-water O-H stretches-consistent with a C(6)H(6)-(H(2)O)n structure in which benzene is on the surface of a cyclic (H(2)O)n cluster. In n = 6 and 7 clusters, the spectra show distinct new transitions in the 3500 to 3600 wave number region. After comparison of these results with the predictions of ab initio calculations on (H(2)O)n clusters, these new transitions have been assigned to double donor O-H stretches associated with the formation of a more compact, noncyclic structure beginning with (H(2)O)(6). This is the same size cluster for which ab initio calculations predict that a changeover to noncyclic (H(2)O)n structures will occur.     

Detection and Characterization of ?-Lactam Resistance in Haemophilus parasuis Strains from Pigs in South China

To characterize the ?-lactam resistance in veterinary clinical isolates of Haemophilus parasuis, 115 isolates were examined for the ?-lactam resistance, the possession of ?-lactamase, and the presence of ?-lactamase genes. The genetic relationship among isolates was evaluated by pulsed-field gel electrophoresis (PFGE). Overall, the commonly detected resistance phenotypes were resistant to ampicillin (26.09%), penicillin (22.61%), amoxicillin (21.74%), cefazolin (14.78%), cefaclor (12.17%), and cefotaxime (6.96%). These strains showed high minimal inhibitory concentration (MICs) to oxacillin. 20.87% strains produced ?-lactamase, and 4.35% strains showed extended-spectrum b-lactamase (ESBL) phenotype. Moreover, 19 strains harboured bla genes including TEM-1 (n=5), TEM-116 (n=10), and ROB-1 (n=5). Significantly, one strain possessed both TEM-1 and ROB-1, and displayed resistance to cefotaxime (MIC=8 mg L^-1). The epidemiological analysis of PFGE revealed high genetic diversity among bla-positive isolates. This work shows that TEM- and ROB-type ?-lactamases are prevalent in H. parasuis isolates in China.     

Isomers of Small Carbon Cluster Anions: Linear Chains with up to 20 Atoms

The structure of small carbon cluster anions, Cn(-) (4 相似文献   

栗园节肢动物群落结构与组织学研究

根据皖东栗园节肢动物群落物种的组成和数量,按照营养和取食关系,将群落划分为植食类、捕食类、寄生类和中性类亚群落,按照系统分类的方法,将每个亚群落分成不同的功能类群,采用群落分析的多个参数比较分析了群落的结构.结果表明,皖东栗园节肢动物调查到了178种101科,其中植食类、捕食类相对丰盛度分别为0.93295和0.04062,各亚群落的优势集中性表现为寄生类(0.68686)>植食类(0.29356)>捕食类(0.24680);H′多样性指数和Hill多样性指数(N1、N2)均为捕食类节肢动物亚群落>节肢动物总群落>植食类节肢动物亚群落.     

Population Genetic Analysis of Blumeria graminis f. sp. tritici in Qinghai Province,China

To gain more precise information about molecular genetic variation for wild populations of Blumeria graminis f. sp. tritici from Qinghai Province, China, 38 single-colony isolates were purified from samples collected from Haidong District, Xining City and Hainan Tibetan Autonomous Prefecture in 2010. The virulence of 21 isolates among them was tested at seedling stage on 34 wheat cultivars (lines) carrying known powdery mildew (Pm) resistant genes. The results showed that V1a, V3a, V3c, V3e, V5a, V6, V7, V8 and V19 had high virulence frequencies (>75%), indicating a wide distribution; and V1c, V5b, V12, V13, V16, V21, VXBD, V2+6, V2+Mld and V4+8, with less distribution, appeared to be lower in frequencies (0-20%). The Nei's gene diversity (H), Shannon's information index (I) and the percentage of polymorphic loci (P) were 0.23, 0.35 and 67.65%, respectively, which revealed a virulent diversity. The results from single nucleotide polymorphisms (SNPs) of 38 isolates showed that three housekeeping genes were found to contain a total of 9 SNP sites. 10 haplotypes (H1-H10) were inferred from the concatenated sequences, with 1 haplotype (H1) comprising of over 55% of Qinghai population. Phylogenic analysis did not show obvious geographical subdivision between the isolates. A multilocus haplotype network presented a radial structure, with H1 in the central as an inferred ancestor. Using analysis of molecular variance (AMOVA), we found 1.63% of the total variation was among populations and 98.37% within populations, with a low fixations index (F_ST=0.01634, P<0.05). This revealed a relatively high genetic diversity but a low genetic divergence in Qinghai population. Moreover, the molecular data on gene flow (Nm=6.32) confirmed the migration of pathogen populations among areas in Qinghai Province.     

重组热带螨Blo t 21变应原诱导小鼠变态反应气道炎症模型的建立

为了建立热带螨重组变应原Blo t 21(rBlo t 21)诱导小鼠变态反应气道炎症模型,笔者利用从NCBI Gen Bank库里获得的热带螨Blo t 21基因序列,进行了序列优化与全基因合成,构建了原核表达载体PQE80LrBlo t 21,在大肠杆菌内诱导表达rBlo t 21,利用镍柱亲和层析纯化rBlo t 21蛋白。12只BALB/c小鼠随机分为对照组(PBS组)与诱导组(rBlo t 21组),每组6只,通过腹腔注射致敏与气道诱导后,分别通过酶联免疫吸附试验(ELISA)检测血清总IgE水平;鼠尾静脉注射变应原诱发应激性过敏反应;HE染色观察小鼠肺部炎症严重程度。本试验成功表达与纯化了重组热带螨变应原Blo t 21。利用纯化的rBlo t 21诱导小鼠变态反应气道炎症模型,与PBS组相比,rBlo t 21组的小鼠血清总IgE水平显著升高,肺部组织细胞侵润明显增加(P0.05)。原核表达纯化的重组Blo t 21变应原能够诱导小鼠产生变态反应气道炎症。     

意大利蜜蜂同日龄不同职能工蜂上颚腺的转录组学分析

为揭示意大利蜜蜂哺育蜂上颚腺中蜂王浆合成和分泌相关的分子机制,通过组建人工蜂群收集3日龄工蜂(3 d)、10日龄哺育蜂(10 dN)、10日龄采集蜂(10 dF)、21日龄哺育蜂(21 dN)和21日龄采集蜂(21 dF),利用高效液相色谱技术检测5种不同职能工蜂上颚腺中10-羟基-2-癸烯酸(10-hydroxy-2...     

Crystal Structure of Hexaazaoctadecahydrocoronene Dication [HAOC]2+, a Singlet Benzene Dication

The structures of hexaazaoctadecahydrocoronene, [HAOC](n) (n = O, + 2), have been determined by single-crystal x-ray diffraction. Although HAOC is aromatic, its dication has a localized structure that is based upon Jahn-Teller-distorted cyanine/p-phenylenediammonium fragments. The structure is consistent with the singlet ground state as determined by magnetic susceptibility and contrasts with the simplest Hückel expectation of a triplet ground state.     

草菇TPI基因的克隆、结构及其在同核、异核菌株中的表达量

分别从不能出菇的草菇单孢菌株PYd21(基因组测序菌株)和PYd15(重测序菌株)及由PYd21、PYd15配对杂交获得可正常出菇的异核菌株H15-21中克隆测序了磷酸丙糖异构酶(TPI)基因,并对TPI基因的结构及其在3个菌株中的表达量进行了分析.结果表明:PYd21、PYd15中TPI基因的序列完全相同;转录组读段定位、双末端分析结果显示,TPI基因全长1015 bp,开放阅读框序列全长756 bp,编码251个氨基酸,有6个外显子、5个内含子;RNA加工过程中存在两种可变剪切类型和两个可变剪切位点;数字基因表达谱测序的结果表明,PYd21、PYd15和H15-21中TPI基因的表达量(TPM)分别为30.25、36.49、77.17,同时通过实时荧光定量PCR分析3个菌株中TPI基因的表达情况证实了该结果,表明草菇中TPI基因的表达表现出异核体表达的协同增效作用,预示着异核菌株中两种不同细胞核存在相互作用.     

心康冲剂调控慢性心衰大鼠miRNA-21/PTEN抗心肌纤维化研究

目的 探讨心康冲剂抗心衰大鼠心肌纤维化的机制。方法 90只SD大鼠分为正常组10只,模型组、对照组及心康低、中、高剂量组各16只。心康低、中、高剂量组分别给予0.5、1、2 g/（kg·d）的心康冲剂溶液。对照组给予0.06 g/（kg·d）的芪苈强心胶囊。正常组、模型组按1 mL/（kg·d）灌服生理盐水。各组均每日1次,连续灌服8周。计算左心室质量指数（LVMI）;心脏切片行HE、Masson染色并计算胶原容积分数（CVF）;采用Real-time PCR法检测miRNA-21、人第10号染色体缺失的磷酸酶及张力蛋白同源基因（PTEN）mRNA表达水平;用Pearson相关及Logistic多元线性回归分析miRNA-21、PTEN mRNA、CVF与LVMI之间的相关性。结果 与正常组比,模型组大鼠心肌CVF、LVMI比值及miRNA-21表达升高（P<0.01）,PTENmRNA表达下降（P<0.01）。与模型组比,心康低、中、高剂三组CVF、LVMI比值及miRNA-21表达下降（P<0.01）、PTENmRNA表达升高（P<0.01）;与芪苈强心组比较,心康冲剂低、中、高剂LVMI、CVF、miRNA-21、PTEN mRNA无明显差异（P>0.05）。miRNA-21、PTENmRNA、CVF均与LVMI有明显线性相关关系。结论 心康冲剂可通过下调miRNA-21、升高PTEN mRNA表达抗心肌纤维化。     

H9亚型AIV型特异性电化学发光免疫检测方法的建立

【目的】H9亚型禽流感是重要的人兽共患性传染病,该亚型病毒为H7N9亚型和H10N8亚型流感病毒提供了6个内部基因（PB2、PB1、PA、NP、M、NS）,并且一直处于动态重组过程中。因此,建立针对H9亚型禽流感的型特异性电化学发光免疫的高通量快速检测方法,加强H9亚型流感的监测,具有重要意义。【方法】用钌联吡啶标记H9亚型AIV的单克隆抗体,用MPI-E型电致化学发光分析系统评价钌标单抗标记效率;用生物素标记H9亚型AIV的多克隆抗体,HABA法检测抗体生物素化的效率;待测抗原与钌标单抗作用1 h后,将此抗原-抗体复合物与通过生物素-链霉亲和素系统固定在磁微球表面的多克隆抗体反应,最后加入反应底物三丙胺后即可在电化学分析系统进行发光检测。优化生物素化多抗和钌标单抗最佳工作浓度,确定临界值和反应谱,对所建立的方法进行敏感性、特异性和重复性试验。攻毒后3 d和5 d,采集攻毒组和空白对照组鸡只的88份咽拭子和肛拭子,分别用电化学发光免疫检测方法和鸡胚病毒分离法进行检测和比较。【结果】钌标抗H9亚型AIV单克隆抗体的标记效率为每个单抗IgG分子上结合21个Ru²⁺,且间接免疫荧光方法证明其仍具有生物活性;生物素化兔抗H9N2亚型AIV多克隆抗体的标记效率为每个IgG分子上结合了6个生物素分子,且Western blotting试验证明其仍保持生物活性;该方法的检测临界值为28.3,可疑区间为23.4-33.2;阴性和阳性变异系数均小于10%;检测限为5×10⁴EID₅₀,能够特异性地检测H9亚型AIV,不与其他亚型流感病毒（H1、H3、H4、H5和H6亚型）和其他类型的禽源病毒（NDV、IBV和IBDV）反应。3 h内即可完成检测,与鸡胚病毒分离法的符合率为86.4%。【结论】所建立的H9亚型AIV型特异性电化学发光免疫检测方法可以用于临床样品检测,对H9亚型禽流感的监测和防控具有重要意义。     

Hydrated electron dynamics: from clusters to bulk

The electronic relaxation dynamics of size-selected (H2O)n-/(D2O)n[25 eaq-(s(dagger)) internal conversion lifetime.     

Dietary arginine supplementation in multiparous sows during lactation improves the weight gain of suckling piglets

This study investigated the effects of dietary arginine(Arg)supplementation,just during lactation,on sow and litter performance,plasma concentrations of metabolites and hormones,and milk yield and composition in multiparous sows.Thirty-one sows were randomly assigned to 3 dietary treatments supplemented with 0.0(control,n=10),0.5%(n=10),or1.0%(n=11)L-Arg-HCl,respectively.Experimental diets were provided to the sows from d 3 to 21 of lactation.Plasma and milk samples were collected at d 14 and 21 of lactation.The average daily gain(ADG)of piglets from sows fed diets supplemented with 0.5 or 1.0%L-Arg-HCl at d 3 to 14 of lactation,were higher than that of controls(P0.05).Maternal supplementation with 1.0%L-Arg-HCl also increased ADG of piglets between d 3 and 21 of lactation than that of the controls(P0.05).There was no significant effect of supplementation on average daily feed intake(ADFI),body weight loss,and backfat thickness loss of lactating sows.Supplementation with 0.5 or 1.0%L-Arg-HCl had a trend towards increasing milk yields and milk fat contents(0.05P0.10);milk protein and lactose were unchanged.Supplementation with 1.0%L-ArgHCl increased plasma concentrations of prolactin and insulin in sows at d 14 and 21 of lactation,and plasma concentrations of non-esterified fatty acid(NEFA),insulin-like growth factor-1(IGF-1),and nitric oxide(NO)in sows at d 21 of lactation,when compared to the controls(P0.05).Supplementation with 1.0%L-Arg-HCl increased IGF-1 and spermine in milk at d 14 of lactation,relative to the controls(P0.05).Plasma Arg concentrations at d 14 and 21 of lactation,as well as plasma NO level and milk IGF-1 at d 21 of lactation,were increased,while plasma urea nitrogen(PUN)concentration at d 14 and21 of lactation was decreased,by supplementation with 0.5 or 1.0%L-Arg-HCl when compared to the controls(P0.05).Collectively,dietary supplementation of multiparous sows with Arg,just during lactation,is beneficial for enhancing litter weight gain but the complete mechanism remains to be determined and may involve in the maternal endocrine changes and milk polyamines contents.