不同抽薹性不结球白菜抽薹过程中碳氮指标的分析

以抽薹性不同的不结球白菜自交系为材料,研究了抽薹前后6个发育阶段叶片中碳水化合物、可溶性蛋白质、游离氨基酸含量的变化。结果表明,可溶性总糖、蔗糖、淀粉含量在花芽分化时不断升高,分化完成后下降,抽薹时又有所升高;还原糖仅在花芽分化中期升高;三个自交系相比,晚抽薹自交系08-1P-89在花芽分化时糖含量最高;可溶性蛋白质和游离氨基酸变化趋势与可溶性总糖基本一致,但游离氨基酸含量在抽薹时明显下降,整个过程中晚抽薹自交系含量都最高;在花芽分化过程和抽薹期,碳氮比呈升高趋势。     

光周期诱导甘蔗花芽分化及成花逆转过程中生理代谢的变化

以两个在自然条件下难开花的甘蔗品种‘ROCl6’和‘ROC22’为材料,研究经光周期诱导甘蔗花芽分化和成花逆转过程中叶片碳水化合物和可溶性蛋白质含量的变化。结果表明,未分化前,两品种经光周期诱导后叶片可溶性总糖、淀粉和蛋白质含量与对照相比无明显变化;从花芽分化诱变期开始,两品种叶片可溶性总糖、淀粉和蛋白质含量迅速增加,明显高于对照（未分化）。随着花芽进一步分化,其叶片可溶性总糖、淀粉含量逐渐降低并低于对照,处在一个较低的水平,蛋白质含量始终高于对照。成花逆转植株在花芽分化前期叶片可溶性总糖、淀粉和蛋白质含量也高于对照,但低于正常抽穗开花植株;之后随着花芽分化的停止,其叶片可溶性总糖、淀粉含量一直保持较稳定的水平,仅蛋白质略有降低。说明甘蔗花芽分化期间大量的基因表达并且合成各种蛋白质的过程需要消耗大量的碳水化合物。     

郁金香花芽分化过程中鳞茎碳水化合物和蛋白质含量的变化

以郁金香的两个品种‘朱迪斯＇（‘Judith Leyster＇）和‘大笑＇（‘Big Smile＇）为材料,采用石蜡切片法确定其花芽分化进程,并测定花芽分化期鳞茎内碳水化合物和可溶性蛋白质含量的变化。结果表明,郁金香花芽分化过程中,两个品种的碳水化合物含量的变化趋势较为接近。随着鳞茎含水量的下降,可溶性总糖和可溶性蛋白含量均呈先增加后减少的趋势。淀粉含量的变化呈现波动性,而淀粉酶活性则持续增强并在后期达到稳定水平。鳞片中可溶性糖含量和淀粉酶活性同时增加是郁金香花芽形态分化启动的标志。相比于外层鳞片,内层鳞片是为花芽原基生长发育提供营养物质的首要场所。     

枣花芽分化过程中营养物质和内源激素含量及抗氧化酶活性变化研究

以新疆主栽品种灰枣和骏枣的花芽为材料,测定不同分化时期花芽的可溶性糖、还原糖、淀粉、可溶性蛋白含量,SOD、POD、PPO、CAT活性以及内源GA₃、IAA、ABA、ZT水平的变化,并分析它们与花芽分化的关系,为枣花芽分化调控提供理论参考。结果表明:(1)灰枣和骏枣花芽可溶性糖、还原糖和淀粉含量在花芽分化过程的变化趋势基本相似,于花原基分化期至雌蕊分化期先降低后升高,至雌蕊分化期到达峰值;而可溶性蛋白质含量变化趋势相反,在花原基分化期至雌蕊分化期先上升再降低。(2)在整个花芽分化过程中,其POD、PPO、CAT活性变化趋势基本一致,从花芽开始分化后逐步降低,最低点出现在雌蕊分化期;两个品种花芽SOD活性在花原基分化期至分化初期时显著上升,之后SOD活性在灰枣中不断降低,而在骏枣中则显著上升。(3)两品种花芽IAA、GA₃、ZT含量在分化过程中的变化规律基本相似,它们均在萼片分化期前呈下降趋势,之后GA₃、ZT含量及灰枣中IAA含量逐渐上升,而骏枣IAA含量在萼片分化期至花瓣分化期呈先显著上升后下降再上升;灰枣ABA含量在花原基分化期至萼片分化期显著上升,而同期骏枣则显著降低,随着分化进程的推进,灰枣ABA含量在萼片分化期后逐步降低,而骏枣则逐步上升并在雌蕊分化期达到峰值。(4)花芽分化开始后,骏枣ABA/IAA、ZT/IAA、GA₃/IAA比值快速上升,但GA₃/ABA、ZT/ABA的比值呈下降趋势;灰枣ZT/IAA、GA₃/IAA在花原基分化期至萼片分化期显著上升后降低,分化结束后低于花原基分化期。研究认为,枣花芽开始分化后会消耗大量的营养物质,导致花芽的可溶性糖、淀粉和还原糖含量降低,且整个分化过程中淀粉含量始终高于可溶性糖和还原糖含量;两个品种枣花芽分化过程中POD、CAT、PPO活性下降以及骏枣花芽分化过程中SOD活性的上升均有利于枣营养生长向生殖生长的转变,且枣花芽分化过程中低水平的GA₃和IAA、中等水平的ABA、较高水平的ZT,以及较高的ZT/IAA、ABA/IAA和GA₃/IAA有利于枣花芽分化和花芽形成。     

A23187和EGTA对光周期诱导菊花成花及其过程中叶片Ca2+分布和碳水化合物的影响

以切花菊品种‘神马’为试材,研究光周期诱导菊花成花过程中Ca²⁺载体A23187和Ca²⁺螯合剂EGTA处理对花芽分化及其过程中叶片Ca²⁺分布和蔗糖、可溶性糖及淀粉含量变化的影响.结果表明：对照叶片Ca²⁺含量在花芽未分化期（Ⅰ）处于较低水平,而在花芽分化启动期（Ⅱ）迅速增加并达到高峰,之后下降;Ca²⁺亚细胞定位表明,在未分化期（Ⅰ）Ca²⁺沉淀主要分布在液泡、细胞壁和细胞间隙中,细胞质内较少,而在花芽分化启动期（Ⅱ）细胞质内积累大量的Ca²⁺沉淀.A23187处理的菊花花芽分化开始和结束时间比对照分别提前2 d和3 d,叶片Ca²⁺含量比对照显著增加;EGTA处理的叶片Ca²⁺含量比对照显著减少,花芽分化开始和结束时间分别比对照推迟4 d和8 d;A23187和EGTA处理的叶片Ca²⁺在花芽分化启动期（Ⅱ）均向细胞质流入并密集.A23187处理的蔗糖和可溶性糖含量在处理2 d时达到峰值,比对照达到峰值的时间提前2 d,与Ca²⁺达到峰值的时间一致,而EGTA处理的蔗糖和可溶性糖含量在处理2 d时没有明显变化,8 d时才迅速增加达到峰值,即所有处理的蔗糖、可溶性总糖含量在花芽分化启动期（Ⅱ）均增加并达到高峰,之后有所减少,但其在整个花芽分化过程均高于光周期诱导前的含量;对照和A23187处理的淀粉含量在处理2 d时开始减少,而EGTA则在处理8 d后开始减少,至花芽分化结束所有处理的淀粉含量均保持较低水平（低于诱导前）.表明Ca²⁺碳水化合物参与了光周期诱导的菊花成花过程.     

德国鸢尾‘常春黄’花芽分化的形态观察及两种代谢产物的动态变化

鸢尾是世界著名观赏花卉,为研究其花芽分化期的形态和生理指标变化情况,我们以德国鸢尾两季花品种‘常春黄’（Iris germanica cv. Lovely Again）为材料,运用扫描电镜（SEM）观察了德国鸢尾‘常春黄’的花芽分化过程。结果表明：整个形态分化过程可分为6个阶段：花序原基分化期、外轮花被分化期、雄蕊分化期、内轮花被分化期、雌蕊分化期、髯毛形成期。结合上述形态分化过程,分别取其二次花花芽分化时期的顶芽、根茎和叶片部位,以蒽酮比色法测定可溶性糖,以考马斯亮蓝G-250法测定蛋白质含量。结果表明：可溶性糖在花序原基分化的初始阶段含量最高,且在3个部位的含量大小关系始终是：根茎﹥叶片﹥顶芽;蛋白质含量呈先上升后下降的趋势,蛋白质含量的峰值出现于花序伸展初期。     

柑桔中间砧对接穗叶片和基砧根系碳水化合物含量的影响

以华红脐橙/3 种中间砧/枳为试材进行田间试验,研究不同中间砧对接穗叶片和基砧根系中碳水化合物含量的双重影响。结果表明,接穗叶片可溶性糖含量、基砧根系淀粉和总糖含量的年动态变化趋势基本相似,而在接穗叶片淀粉含量年动态变化的早期趋势和总糖含量年动态变化的后期趋势、基砧根系可溶性糖含量的年动态变化趋势上则有明显的差异。在一年中的绝大多数时期里,接穗叶片和基砧根系的 3 种碳水化合物含量在不同中间砧之间有明显的差异。     

穗花牡荆花芽分化过程中形态和生理指标变化

以穗花牡荆为研究材料,通过探究其花芽分化进程和生理特性,为花期调控技术提供成花机理。采用物候期观察和石蜡切片相结合的方法并测定花芽分化过程中相关生理指标,研究花发育过程中的形态和生理变化。结果表明,穗花牡荆花芽分化为一年多次分化型,其进程可划分为七个时期：未分化期、总轴花序原基分化期、初级分轴花序原基分化期、次级分轴花序原基分化期、小花原基分化期、花器官分化前期和花器官分化后期。同一植株不同位置花芽及同一花序中不同单花分化的进程不同,第一季花期后各阶段的花芽分化形态常存在重叠。花芽分化过程中不同时期叶片和花芽的可溶性糖和可溶性蛋白质含量均有上升下降的变化,总体上叶片中营养物质含量高于花芽保证营养供应。花芽分化过程中,IAA、ABA、CTK和GA3整体水平上先升后降有利于花芽分化进行。研究认为,花芽中大量的可溶性糖和蛋白质积累及较高的碳氮比,有利于穗花牡荆花芽形态分化顺利完成。低水平的GA3/ABA和IAA/CTK有利于花序的形成,ABA/CTK和ABA/IAA比值升高促进小花原基和小花萼片原基的分化, GA3/CTK、GA3/ABA和GA3/IAA比值升高促进花瓣原基、雄雌蕊原基发育。     

sh-2超甜玉米乳熟期籽粒重量和碳水化合物变化及与温度降雨量的回归分析

采用夏季不同播期,研究了sh-2型超甜玉米乳熟期籽粒重量和碳水化合物的变化,用多重回归分析方法对气温、降雨量与籽粒重量、碳水化合物含量的关系进行了分析．结果表明,两个播期的可溶性总糖、果糖、蔗糖含量变化趋势有明显差异．夏季早播,提高了乳熟期籽粒鲜重和干重,灌浆速率,可溶性总糖和淀粉含量．说明夏季早播有利于提高甜玉米的独特甜风味和产量构成．移栽-收获期的T（温差）、K（有效积温）和RF（降雨量）是影响乳熟期籽粒鲜重和干重及可溶性总糖、果糖、蔗糖、淀粉含量的主要因子,K、RF表现正相关效应;在授粉-收获期,K是影响的主要因子,K与籽粒鲜重和干重及果糖、淀粉含量呈正相关,与籽粒蔗糖含量呈负相关．     

百合鳞茎发育过程中碳水化合物含量及淀粉酶活性变化

以兰州百合和亚洲系"精粹"百合为试材,探讨了鳞茎发育过程中不同部位淀粉、可溶性糖含量和淀粉酶活性的变化。结果表明,母鳞茎作为百合萌发阶段的代谢源,其外部鳞片是代谢更为活跃的部位。淀粉和可溶性糖含量同时增加是百合新鳞茎开始膨大的标志。蔗糖是百合鳞茎中可溶性糖的主要形态,还原糖的变化体现了碳水化合物的供应及转化。淀粉酶在百合鳞茎发育过程中对调节和平衡碳水化合物的形态起重要作用。     

壳聚糖酶的克隆表达与壳寡糖的制备分析

目的:克隆壳聚糖酶基因于大肠杆菌中实现高表达,制备壳寡糖。方法:以枯草芽孢杆菌总DNA为模板扩增壳聚糖酶基因(CSN),克隆至载体pET23a(+)上,转化菌株BL21(DE3)。重组子经0.5 mmol/L IPTG诱导后,SDS-PAGE和质谱检测与鉴定重组酶。酶纯化后水解壳聚糖,薄层色谱分析其水解产物。结果:质谱证明壳聚糖酶(31.5kDa)成功表达,表达量占菌体总蛋白的45%左右。纯化后重组酶浓度为900 mg/L,纯度95%、回收率85%,酶活力为10 000 U/mg。壳聚糖降解产物为壳二糖至壳四糖。结论:原核表达载体pET23a(+)-CSN构建正确,壳聚糖酶表达量与活性高,适用于水解壳聚糖制备壳寡糖。     

国内外蝗害治理技术现状与展望

本文首先概述了国内外蝗虫发生与为害的态势,总结了现阶段我国蝗虫发生与为害的主要特点:即农田飞蝗暴发频繁而且严重,草原土蝗的发生时常造成严重的经济损失,而且侵入城市干扰市民生活,我国与周边国家之间蝗虫过境迁移频繁,使用化学农药污染环境和农产品;分析了国内外蝗虫防治对策与技术的发展现状,重点介绍了应急防治和可持续治理对策、...     

Molecular characterisation of species and genotypes of Cryptosporidium and Giardia and assessment of zoonotic transmission

The molecular characterisation of species and genotypes of Cryptosporidium and Giardia is essential for accurately identifying organisms and assessing zoonotic transmission. Results of recent molecular epidemiological studies strongly suggest that zoonotic transmission plays an important role in cryptosporidiosis epidemiology. In such cases the most prevalent zoonotic species is Cryptosporidium parvum. Genotyping and subtyping data suggest that zoonotic transmission is not as prevalent in the epidemiology of giardiasis. Molecular characterisation of Cryptosporidium and Giardia is a relatively recent application that is evolving as new genes are found that increase the accuracy of identification while discovering a greater diversity of species and yet unnamed taxa within these two important genera. As molecular data accumulate, our understanding of the role of zoonotic transmission in epidemiology and clinical manifestations is becoming clearer.     

Comparison of BMI and percentage of body fat of Indian and German children and adolescents

Today, serious health problems as overweight and obesity are not just constricted to the developed world, but also increase in the developing countries (Prentice 2006, Ramachandram et al. 2002). Focusing on this issue, BMI and percentage of body fat were compared in 2094 schoolchildren from two cross-sectional studies from India and Germany investigated in 2008 and 2009. The German children are in all age groups significantly taller, whereas the Indian children show higher values in BMI (e.g. 12 years: Indian: around 22 kg/m2; German: around 19 kg/m2) and in the percentage of body fat (e.g. 12 years: Indian: around 27%; German: around 18-20%) in most of the investigated age groups. The Indian children have significantly higher BMI between 10 and 13 (boys) respectively 14 years (girls). Indian children showed significant higher percentage of body fat between 10 and 15 years (boys) and between 8 and 16 years (girls). The difference in overweight between Indian and German children was strongest at 11 (boys) and 12 (girls) years: 70% of the Indian but 20% of the German children were classified as overweight. In countries such as India that undergo nutritional transition, a rapid increase in obesity and overweight is observed. In contrast to the industrialized countries, the risk of overweight in developing countries is associated with high socioeconomic status. Other reasons of the rapid increase of overweight in the developing countries caused by different environmental or genetic factors are discussed.     

Carnitine and creatine content of tissues of normal and alloxan-diabetic sheep and rats

The concentration of carnitine in liver increased 28-fold and urinary carnitine excretion 5-fold in alloxan-diabetic sheep. In contrast there were no similar increases in alloxan-diabetic rats. The creatine content of liver decreased 3-fold and creatine excretion decreased 2-fold in diabetic sheep. In contrast the creatine content of liver increased nearly 4-fold in diabetic rats with no change in creatine excretion. The marked increased in production of carnitine by the liver of the diabetic sheep appears possible because of decreased production and excretion of creatine.     

Coiled-coil nanomechanics and uncoiling and unfolding of the superhelix and alpha-helices of myosin

The nanomechanical properties of the coiled-coils of myosin are fundamentally important in understanding muscle assembly and contraction. Force spectra of single molecules of double-headed myosin, single-headed myosin, and coiled-coil tail fragments were acquired with an atomic force microscope and displayed characteristic triphasic force-distance responses to stretch: a rise phase (R) and a plateau phase (P) and an exponential phase (E). The R and P phases arise mainly from the stretching of the coiled-coils, with the hinge region being the main contributor to the rise phase at low force. Only the E phase was analyzable by the worm-like chain model of polymer elasticity. Restrained molecular mechanics simulations on an existing x-ray structure of scallop S2 yielded force spectra with either two or three phases, depending on the mode of stretch. It revealed that coiled-coil chains separate completely near the end of the P phase and the stretching of the unfolded chains gives rise to the E phase. Extensive conformational searching yielded a P phase force near 40 pN that agreed well with the experimental value. We suggest that the flexible and elastic S2 region, particularly the hinge region, may undergo force-induced unfolding and extend reversibly during actomyosin powerstroke.     

Synthesis and turnover of cerebrosides and phosphatidylserine of myelin and microsomal fractions of adult and developing rat brain.

The synthesis and turnover of cerebrosides and phospholipids was followed in microsomal and myelin fractions of developing and adult rat brains after an intracerebral injection of [U-14C]serine. The kinetics of incorporation of radioactivity into microsomal and myelin cerebrosides indicate the possibility of a precursor-product relationship between cerebrosides of these membranes. The specific radioactivity of myelin cerebrosides was corrected for the deposition of newly formed cerebrosides in myelin. Multiphasic curves were obtained for the decline in specific radioactivity of myelin and microsomal cerebrosides, suggesting different cerebroside pools in these membranes. The half-life of the fast turning-over pool of cerebrosides of myelin was 7 and 22 days for the developing and adult rat brain respectively. The half-life of the slowly turning-over pool of myelin cerebrosides was about 145 days for both groups of animals. The half-life of the rapidly turning-over microsomal cerebrosides was calculated to be 20 and 40 h for the developing and adult animals respectively. The half-life of the intermediate and slowly turning-over microsomal cerebrosides was 11 and 60 days respectively, for both groups of animals. The amount of incorporation of radioactivity into microsomal cerebrosides from L-serine was greatly decreased in the adult animals, and greater amounts of the precursor were directed towards the synthesis of phosphatidylserine. In the developing animals, considerable amounts of cerebrosides were synthesized from L-serine, besides phosphatidylserine. The time-course of incorporation indicated that a precursor-product relationship exists between microsomal and myelin phosphatidylserine. The half-life of microsomal phosphatidylserine was calculated to be about 8 h for the fast turning-over pool in both groups of animals.