西瓜花叶病毒诱导对不同抗性美洲南瓜防卫基因表达的影响

为了明确防卫基因PAL与美洲南瓜抗西瓜花叶病毒(watermelon mosaic virus,WMV)之间的关系,通过室内接种和实时荧光定量PCR技术,测定了WMV侵染对不同抗性美洲南瓜体内防卫基因PAL表达的影响。结果表明:(1)室内测定显示,抗病品种GBRV-8发病率和病情指数(15.6%和14.2)显著低于感病品种‘光板’(91.1%和65.9)。(2)实时荧光定量PCR表明,接种WMV后不同抗感品种不同组织部位PAL基因相对表达量随着接种时间增加,整体呈现出先增加后降低的趋势,而且不同组织部位PAL基因相对表达量总体呈现出叶片较高,叶柄和茎秆次之。(3)接种后5个品种不同组织部位PAL基因相对表达量与对照相比均存在显著差异,且抗病和中抗品种不同组织部位PAL基因相对表达量显著高于感病品种,尤其抗病品种GBRV-8不同组织部位PAL基因相对表达量最高,感病品种光板最低。研究认为,防卫基因PAL表达量与美洲南瓜品种抗病毒病强弱密切相关。     

银杏胚珠发育进程的解剖学研究

以15 a生银杏(Ginkgo bilobaL.)品种‘佛指’(G.bilobacv.‘Fozhi’)为材料,观察了授粉后胚珠结构、雌配子体发育和种皮分化形成的过程。结果表明:(1)授粉后2 d胚珠已分化出珠心、珠被和珠托组织,珠被顶端形成直径为162.16μm的珠孔与540.54μm长的珠孔道,珠心组织顶端形成长约520.83μm、最大直径约125.06μm的瓶状贮粉室,花粉粒经珠孔道已到达贮粉室并在其中停留;(2)雌配子体的发育先后经历了游离核阶段(授粉后5~30 d)和细胞化阶段(授粉后30~45 d),之后在近珠孔端形成颈卵器,其余部分发育为胚乳薄壁细胞,其营养物质的积累高峰期为授粉后60~80 d;(3)种皮分化与形成分别经历珠被分化期(授粉期至授粉后30 d)、种皮分化期(授粉后30~50 d)、种皮形成初期(授粉后50~80 d)、种皮形成期(授粉后80~90 d)。     

东方百合系内杂交授粉技术与胚抢救技术研究

研究了东方百合系内杂交授粉技术及胚抢救技术。结果表明:(1)在组合‘Justina’בShela’中,采用柱头直接授粉,花粉管在花柱中向下定向生长,在子房中向胚珠定向生长;采用切花柱授粉,花粉管在花柱切口及子房中发生不同程度无向性生长;残留花柱越长,进行胚珠定向的花粉管数量越多,获得的饱满种子越少,采用柱头直接授粉获得的饱满种子最多。(2)采用柱头直接授粉对东方百合系内56个组合进行杂交实验,仅1个组合未获得饱满胚珠、3个组合获得胚珠少于10个,其余52个组合获得大量饱满胚珠,初步表明此法可作为东方百合系内杂交通用授粉技术。不同胚抢救技术试验结果显示,授粉约70d后采用切胚珠接种比胚珠直接接种的杂种胚萌动快、萌发率高,而且前者的胚抢救效率也明显高于授粉40d后的"剥胚式接种"。研究认为,授粉约70d后采用"切胚珠接种"可作为东方百合系内杂交通用胚抢救技术。     

华北驼绒藜繁育系统研究

通过定株观察、人工套袋授粉试验等对华北驼绒藜繁育系统进行了研究。结果显示:(1)华北驼绒藜的花粉寿命为6d,花粉胚珠比(P/O)为1 351 189±391 779;自然条件下存在着同株授粉和异株授粉两种方式,但以异株授粉为主,其繁育系统属于兼性异交。(2)华北驼绒藜在有花粉时柱头可授性为6d(柱头露出后5～10d),但在缺乏花粉不能完成授精时,柱头会出现徒长现象,其可授性可以维持12d(柱头露出后9～20d)。(3)人工套袋授粉结果显示,华北驼绒藜最佳授粉时间是柱头露出后6～7d,此时年均授粉结实率最高(94.83%);在柱头失去过氧化物酶活性时(柱头露出后21d)授粉结实率年均为4.93%;相对于柱头最佳可授期,华北驼绒藜具有较高结实率的授粉时间范围较宽。研究表明,在长期的进化过程中,华北驼绒藜形成了P/O较高、柱头可授性时间长以及在异株授粉优势的情况下,还保留同株授粉方式的生殖补偿机制,对其野生退化群落的种群恢复具有积极的意义。     

高山杜鹃与大喇叭杜鹃种间杂交过程的观察研究

以高山杜鹃‘Nova Zembla’为母本,大喇叭杜鹃为父本进行人工杂交授粉,利用荧光显微镜对杂交组合花粉萌发及花粉管生长过程进行观察,并统计其杂交的田间坐果率。结果显示:(1)授粉后1d花粉开始萌发形成花粉管,其萌发率在授粉后1～5d内显著增长,其后增长缓慢,到第12天萌发率最高达37.36%。(2)花粉萌发后花粉管生长速度由慢变快,授粉后2d花粉管进入花柱,7d进入子房,10d进入胚珠;实验中杂交花粉管与胚珠虽有结合,但与胚珠结合率低,授粉后12d仅7.42条花粉管进入胚珠。(3)在花粉管生长过程中,伴有大量异常现象,表现为授粉后柱头细胞、花粉管、花柱引导组织、子房组织、胚珠中的胚囊等部位依次出现胼胝质沉积反应,花粉管生长中出现的膨大、先端沉积胼胝塞而中途停止生长、螺旋扭曲、粗细不均、杂乱生长或螺旋膨大且逆向生长等异常。(4)该实验杂交的田间坐果率为零。研究表明,高山杜鹃‘Nova Zembla’与大喇叭杜鹃杂交不亲和,杂交后花粉管生长的异常行为可能是种间杂交不亲和的主要原因,且受精前障碍与受精后障碍可能同时存在。     

石榴4-香豆酸辅酶A连接酶基因的克隆和表达分析

4-香豆酸辅酶A连接酶(4-coumarate-CoA ligase,4CL)是木质素合成途径的关键酶。该研究以‘红玉石籽’(Punica granatum cv.Hongyushizi)石榴为试验材料,采用RACE和RT-PCR方法获得4CL同源基因Pg4CL。Pg4CL基因cDNA全长2 121bp,编码544个氨基酸;序列比对和功能域分析发现,Pg4CL包含有2个保守域SSGTTGLPKGV和GEICIRG;系统进化树分析显示,Pg4CL与其他物种起源相同,而与赤桉Ec4CL亲缘关系最近。荧光定量PCR分析表明,Pg4CL基因在叶、果皮、种皮和茎等组织中均有表达,其中果皮和叶片中表达量较高,种皮中表达量最低;Pg4CL基因在6个石榴品种的种皮中均有表达,其中在‘突尼斯软籽’中表达较高,‘会理软籽’表达量最低;Pg4CL基因在‘红玉石籽’籽粒的不同时期均有表达,在15~60d相对表达量逐步上升,并在60d时达到最高;75d以后表达量急剧下降,仅维持较低水平表达。     

海滨锦葵花内五柱头裂片弯曲的独自调节(英文)

海滨锦葵花柱有5柱头裂片,若传粉失败,柱头裂片向下弯曲使柱头与自身花粉接触,发生延迟自交。传粉不足条件下发生的延迟自交可能提供繁殖保障。该研究定量分析了花粉搁置和授精胚珠数对花内未授粉柱头裂片运动的影响,并测定了花粉—胚珠比及柱头可授性和花粉生活力。结果表明,花内未授粉柱头裂片的弯曲不受其他柱头接受花粉量及授精胚珠数的影响,仅响应于其自身是否接受到花粉,花粉-胚珠比值显示海滨锦葵交配系统属兼性异交;未授粉柱头经弯曲与自身花粉授触时的强柱头可授粉和高花粉生活力为自交授粉的发生提供了可能。包括柱头裂片运动在内的多个花性状有机地展示了一种新花内混合交配系统,且花内柱头裂片弯曲的独自调节为从花水平验证被广泛接受的自交进化解释——繁殖保障假说提供了可能。     

荒漠孑遗植物裸果木的花部特征及繁育系统

裸果木是亚洲中部荒漠区少有的第三纪孑遗物种,也是构成石质荒漠植被群落的重要建群种之一,由于人为干扰,其自然种群处于不断衰退中。本文通过野外观察和人工授粉实验等方法,对裸果木的花部特征及繁育系统进行研究,对于揭示该物种生活史特征并探讨影响其生殖成功的因素及制定相应的保护和管理策略具有重要意义。结果表明:裸果木为两性花,花小,无花瓣,雄蕊10枚,外轮5枚雄蕊败育,胚珠1枚,开花盛期有少量花蜜并散发浓烈难闻气味,花粉活力和柱头可授性之间存在46 h的重叠期,且不完全雌性先熟,柱头和花药在多数花的单花花期结束时并未接触,因此,裸果木花主要表现为适应异花传粉的雌雄异位特征;花粉/胚珠比(P/O)为1371.67±236.21,异交系数(OCI)为3;不同花粉来源(自然授粉、自花授粉、同株异花和异株异花授粉)的花粉在柱头上均能萌发,但花粉管生长速度存在差异,同株异花授粉和异株异花授粉的花粉管生长速度较快,自花授粉的花粉管生长速度最慢且部分花粉管(43%)在到达子房时停止生长,并未到达胚珠;人工套袋实验的结果表明,裸果木不存在无融合生殖,自然结种子数低,自然授粉花的种子数远远低于人工异株异花授粉花,说明存在由于异花传粉者不足造成的传粉限制。裸果木部分雌性先熟和雌雄异位是两性花为避免雌雄功能重叠,促进异交而采取的一种花部机制,其繁育系统为兼性异交类型且需要传粉者,部分自交不亲和和传粉限制是影响该物种有性生殖成功的主要因素。     

棉花胚珠内种皮特异基因GhIAA16的分离鉴定

棉花(Gossypium hirsutum L.)纤维是由胚珠外珠被表皮细胞发育形成的一种单细胞表皮毛。为了分析鉴定与棉花胚珠发育相关的基因,本文通过cDNA阵列方法分离了25个在开花前后棉花胚珠中差异表达的基因。其中一个基因与拟南芥IAA16具有很高的同源性,并命名为GhIAA16。 该基因编码一个208个氨基酸组成预测蛋白。分子生物学分析表明它在棉花基因组中以单拷贝形式存在,而且在棉花胚珠内种皮(endothelium)中特异表达。GhIAA16是棉花中第一个分离到的内种皮特异表达的基因,本文对它在棉花胚珠发育中的可能功能进行了讨论。     

棉花胚珠内种皮特异基因GhIAA16的分离鉴定

棉花(Gossypium hirsutum L.)纤维是由胚珠外珠被表皮细胞发育形成的一种单细胞表皮毛.为了分析鉴定与棉花胚珠发育相关的基因,本文通过cDNA阵列方法分离了25个在开花前后棉花胚珠中差异表达的基因.其中一个基因与拟南芥IAA16具有很高的同源性,并命名为GhIAAl6.该基因编码一个208个氨基酸组成预测蛋白.分子生物学分析表明它在棉花基因组中以单拷贝形式存在,而且在棉花胚珠内种皮(endothelium)中特异表达.GhIAAl6是棉花中第一个分离到的内种皮特异表达的基因,本文对它在棉花胚珠发育中的可能功能进行了讨论.     

Effects of MULTIFOLIATE-PINNA, AFILA, TENDRIL-LESS and UNIFOLIATA genes on leafblade architecture in Pisum sativum

In order to dissect the genetic regulation of leafblade morphogenesis, 16 genotypes of pea, constructed by combining the wild-type and mutant alleles of MFP, AF, TL and UNI genes, were quantitatively phenotyped. The morphological features of the three domains of leafblades of four genotypes, unknown earlier, were described. All the genotypes were found to differ in leafblade morphology. It was evident that MFP and TL functions acted as repressor of pinna ramification, in the distal domain. These functions, with and without interaction with UNI, also repressed the ramification of proximal pinnae in the absence of AF function. The expression of MFP and TL required UNI function. AF function was found to control leafblade architecture multifariously. The earlier identified role of AF as a repressor of UNI in the proximal domain was confirmed. Negative control of AF on the UNI-dependent pinna ramification in the distal domain was revealed. It was found that AF establishes a boundary between proximal and distal domains and activates formation of leaflet pinnae in the proximal domain.     

Presence of Rhizobium Etli bv . Phaseoli and Rhizobium Gallicum bv . Gallicum in Egyptian Soils

Seven bean rhizobial strains EBRI 2, 3, 21, 24, 26, 27 and 29 identified as Rhizobium etli, and EBRI 32 identified as Rhizobium gallicum, isolated from Egyptian soils and which nodulated Phaseolus vulgaris efficiently, were subjected to hybridization with a nifH probe in order to estimate the copy number of this gene. Seven strains (EBRI 2, 3, 21, 24, 26, 27 and 29) which were only able to nodulate Phaseolus vulgaris, contained three copies of the nifH gene, consistent with their identification as Rhizobium etli bv. phaseoli. Only one strain (EBRI 32) which nodulated both Phaseolus vulgaris and Leucaena leucocephala, had one copy of nifH gene. This confirmed the classification of this strain as Rhizobium gallicum bv. gallicum.     

Characterisation of cell wall polysaccharides, arabinogalactans-proteins (AGPs) and phenolics of Cola nitida, Cola acuminata and Garcinia kola seeds

Many Cola plant species are endemic to West and Central Africa. Cola acuminata and Cola nitida are used as masticatory when fresh, while the dried nuts are used for beverages and pharmaceutical purposes in Europe and North America. Garcinia kola seeds, that serve as a substitute for the true kola nuts, are used in African traditional medicine for the treatment of various diseases, including colic, headache and liver cirrhosis. Seeds extracts of G. kola are also known for their anti-inflammatory, antimicrobial and antiviral properties. To gain information on the chemical properties of the kolas, we have isolated and analyzed cell wall polysaccharides, arabinogalactan-proteins and phenolic substances from the seeds of the three kola species. The sugar composition of cell wall material of C. acuminata, C. nitida and G. kola revealed that Gal (up to 30%), Ara, GalA and Glc as the predominant monosaccharides, representing approximately 90% by mol of the total hydrolysable sugar present in this material. In Ammonium oxalate cell wall fraction, GalA was found to be the major sugar present in all kola species. In the alkali-soluble fraction, there were significant differences in the level of Glc and Gal. The level of Glc was high in C. acuminata and C. nitida while the level of Gal and Xyl were high in C. nitida and G. cola. Isolation and quantification of arabinogalactan-proteins demonstrate that G. kola seeds contained four to eight times more of these proteoglycans than the seeds of the other two species. Finally, analysis of soluble phenolic substances shows that caffeine and catechin were largely represented in C. acumina and C. nitida seeds, with caffeine accounting for 50% of all soluble phenolics. These findings indicate that the three Kola seeds are highly enriched in pectins and proteoglycans and that C. acuminata and C. nitida can be used as a possible source of caffeine and catechin.     

Comparative study of Bifidobacteriumanimalis, Escherichiacoli, Lactobacilluscasei and Saccharomycesboulardii probiotic properties

The present work investigates some probiotic properties of four different microorganisms (Bifidobacterium animalis var. lactis BB-12, Escherichia coli EMO, Lactobacillus casei and Saccharomyces boulardii). In vitro and in vivo tests were carried out to compare cell wall hydrophobicity, production of antagonistic substances, survival capacity in the gastrointestinal tract of germ-free mice without pathological consequence, and immune modulation by stimulation of Küpffer cells, intestinal sIgA and IL-10 levels. In vitro antagonism against pathogenic bacteria and yeast was only observed for the probiotic bacteria B. animalis and L. casei. The hydrophobic property of the cell wall was higher for B. animalis and E. coli EMO, and this property could be responsible for a better ability to colonize the gastrointestinal tract of germ-free mice. Higher levels of sIgA were observed mainly for S. boulardii, followed by E. coli EMO and B. animalis, and only S. boulardii induced a significant higher level of IL-10. In conclusion, for a probiotic use, S. boulardii presented better characteristics in terms of immunomodulation, and B. animalis and L. casei for antagonistic substance production. The knowledge of the different probiotic properties could be used to choice the better microorganism depending on the therapeutic or prophylactic application.     

Prosthecium species with Stegonsporium anamorphs on Acer

Data from microscopic morphology, single-spore cultures, and DNA analyses of teleomorphs and anamorphs support the recognition of five species of Prosthecium with Stegonsporium anamorphs on Acer: P. acerinum sp. nov., the teleomorph of S. acerinum; P. acerophilum comb. nov., formerly known as Dictyoporthe acerophila; P. galeatum comb. nov., originally described as Massaria galeata; P. opalus sp. nov.; and P. pyriforme sp. nov., the teleomorph of S. pyriforme s. str. The morphology of both type specimens and freshly collected material was investigated. The teleomorphs have brown ellipsoidal ascospores with five distosepta and often a longitudinal distoseptum. The anamorphs of all species described here belong to Stegonsporium; their connection to the Prosthecium teleomorphs was demonstrated by morphology and DNA sequences of single spore cultures derived from both ascospores and conidia. The anamorphs and teleomorphs of all five Prosthecium species are described and illustrated by LM images, and a key to these species is provided. As perceived from this work, S. pyriforme is restricted to Europe and does not occur in North America, whereas S. acerinum is restricted to North America, not found in Europe. The host associations given in the literature are revised and evidence is provided that only A. opalus, A. pseudoplatanus, and A. saccharum are confirmed hosts of Prosthecium with Stegonsporium anamorphs. Molecular phylogenetic analyses of tef1, ITS rDNA, and partial nuLSU rDNA sequences confirm that the species with Stegonsporium anamorphs are closely related to P. ellipsosporum, the generic type species. Stilbospora macrosperma is confirmed as the anamorph of P. ellipsosporum by DNA data of single spore isolates obtained from both ascospores and conidia.     

铜绿假单胞菌对青霉素类抗生素异质性耐药研究

【背景】铜绿假单胞菌是临床上常见的条件致病菌,其异质性耐药的发生常导致临床治疗失败。【目的】研究铜绿假单胞菌对青霉素类抗生素的异质性耐药情况,为相关临床感染治疗提供一定的依据。【方法】收集临床分离的50株铜绿假单胞菌,采用纸片扩散法(diskdiffusion method)即Kirby-Bauer (K-B)法、菌落谱型分析(population analysis profile,PAP)法、生长实验以及传代稳定性实验探究铜绿假单胞菌的异质性耐药特征。【结果】K-B法初筛得到铜绿假单胞菌对哌拉西林(piperacillin,PIP)、哌拉西林/他唑巴坦(piperacillin/tazobactam,TZP)和替卡西林/克拉维酸(ticarcillin/clavulanic acid,TIM)的异质性耐药率分别为52%、52%和54%。PAP实验确认后有13株异质性耐药菌,其检出率占总实验菌株的26%。随机选取8株异质性耐药菌株,其耐药亚群的发生频率为7.3×10-7-1.2×10-5。通过无抗生素压力的生长实验发现,异质性耐药菌株PAS92、PAS57与其各自的3株最高PIP浓度平...     

Probing the Drosophila retinal determination gene network in Tribolium (II): The Pax6 genes eyeless and twin of eyeless

The Pax6 genes eyeless (ey) and twin of eyeless (toy) are upstream regulators in the retinal determination gene network (RDGN), which instructs the formation of the adult eye primordium in Drosophila. Most animals possess a singleton Pax6 ortholog, but the dependence of eye development on Pax6 is widely conserved. A rare exception is given by the larval eyes of Drosophila, which develop independently of ey and toy. To obtain insight into the origin of differential larval and adult eye regulation, we studied the function of toy and ey in the red flour beetle Tribolium castaneum. We find that single and combinatorial knockdown of toy and ey affect larval eye development strongly but adult eye development only mildly in this primitive hemimetabolous species. Compound eye-loss, however, was provoked when ey and toy were RNAi-silenced in combination with the early retinal gene dachshund (dac). We propose that these data reflect a role of Pax6 during regional specification in the developing head and that the subsequent maintenance and growth of the adult eye primordium is regulated partly by redundant and partly by specific functions of toy, ey and dac in Tribolium. The results from embryonic knockdown and comparative protein sequence analysis lead us further to conclude that Tribolium represents an ancestral state of redundant control by ey and toy.     

转Cry1Ac/1Ab基因棉花对异色瓢虫生长发育及其捕食功能的影响

【目的】为探究转Cry1Ac/1Ab基因棉花对异色瓢虫生长发育及其捕食功能的影响。【方法】以转Cry1Ac/1Ab基因棉与其亲本常规棉为实验材料,利用取食不同棉花品种叶片的棉铃虫饲喂异色瓢虫幼虫。【结果】与常规亲本棉相比,取食饲喂转基因棉花叶片的初孵棉铃虫幼虫的异色瓢虫幼虫从1龄发育至化蛹期时间延长0.77 d,但差异不显著;除1龄幼虫体重增加(0.0773 mg)外,其余各龄期幼虫体重均有所下降,但差异均不显著;异色瓢虫1、2、3、4龄幼虫对初孵棉铃虫捕食量均随棉铃虫密度的增加而增加,捕食功能反应均符合HollingⅡ圆盘方程。【结论】转Cry1Ac/1Ab基因棉花对异色瓢虫生长发育无显著影响,饲喂取食转Cry1Ac/1Ab基因棉花的棉铃虫对异色瓢虫捕食功能无显著差异。