Flower-inducing and -inhibiting activities of Phloem Exudate from Cotyledons of Pharbitis Seedlings

The flower-inducing and -inhibiting activities of phloem exudate (PE) prepared from cotyledons of Pharbitis seedlings were examined, using apex cultures in vitro from Pharbitis as a bioassay system.The PE was prepared from photoperiodically-induced cotyledons (SD-PE). The SD-PE was subjected to the following fractionations: When the SD-PE was extracted with CHCl₃ and then ethyl acetate, the inducing activity was located in the final aqueous fraction. The activity was localized in the diffusate when the aqueous fraction was dialyzed (molecular weight cut off was 10,000). The diffusate was fractionated by ion exchange chromatography, and flower-inducing activity was found in the fraction adsorbed onto anion exchange resin. When the fraction was applied to a Sep-Pak C18 cartridge, the activity eluted with 25% MeOH. As a result of the above fractionation, activity was increased about 30-fold.The nature of the flower-inhibiting activity of the PE taken from cotyledons exposed to continuous-light conditions was examined (CL-PE). The inhibiting activity was decreased as the cotyledons were exposed to longer dark periods; it appeared to be heat-stable. The CL-PE also inhibited flowering in Lemna. The CL-PE was subjected to the following fractionations: When the CL-PE was extracted with CHCl₃ and ethyl acetate, activity was located in the final aqueous fraction. Activity was localized in the diffusate when the aqueous fraction was dialyzed (molecular weight cut off was 10,000). When the diffusate was fractionated by ion exchange chromatography, the activity was found in the flow-through fraction. When the fraction was applied to a hydroxyapatite cartridge, the activity eluted with 25 mM sodium phosphate buffer. When the fraction was re-dialyzed (molecular weight cut off was 1,000), the diffusate contained the activity. As a result of the above fractionation, activity was increased about 10-fold.     

The kinetics of baculovirus adsorption to insect cells in suspension culture

The influence of various culture parameters on the attachment of a recombinant baculovirus to suspended insect cells was examined under normal culture conditions. These parameters included cell density, multiplicity of infection, and composition of the cell growth medium. It was found that the fractional rate of virus attachment was independent of the multiplicity of infection but dependent on the cell density. A first order mathematical model was used to simulate the adsorption kinetics and predict the efficiency of virus attachment under the various culture conditions. This calculated efficiency of virus attachment was observed to decrease at high cell densities, which was attributed to cell clumping. It was also observed that virus attachment was more efficient in Sf900II serum free medium than it was in IPL-41 serum-supplemented medium. This effect was attributed to the protein in serum which may coat the cells and so inhibit adsorption. A general discussion relating the observations made in-these experiments to the kinetics of recombinant baculovirus adsorption to suspended insect cells is presented.     

Comparative toxic and sublethal effects of fluvalinate on two-spotted spider mite and European red mite

Four fluvalinate formulations differed in their residual toxicity to female two-spotted spider mite (TSM), Tetranychus urticae adults; the emulsifiable concentrate (EC) was the most toxic. In contrast, there was little difference in toxicity between the formulations with the European red mite (ERM) Panonychus ulmi with the exception of the EC formulation which was the least toxic. Fluvalinate 2F caused minimal (<10%) TSM and ERM egg mortality. Fluvalinate 2F was more toxic and caused greater larval dispersal for the TSM compared to the ERM at the field concentration and below. The toxicity of fluvalinate 2F to TSM and ERM protonymphs, deutonymphs and adults was low, approximately <20% at field concentration. Dispersal was the main response to fluvalinate and this was positively correlated with increasing concentration. The combined mortality and dispersal LC₅₀ was five times lower for ERM protonymphs and adults, but 11 times higher for ERM deutonymphs compared to equivalent TSM life stages. Fluvalinate 2F reduced TSM development from the protonymph and deutonymph stages to a greater extent compared to the ERM. The mortality response to fluvalinate 2F was unaffected by host type (peach or apple) for the TSM whereas ERM mortality was higher on apple compared to peach. TSM dispersal was higher from apple compared to peach whereas ERM dispersal was similar on both host types. Oviposition by both mite species was lower on apple than peach leaves. A 1 h exposure to fluvalinate 2F reduced ERM oviposition for 12 days.     

高校《普通动物学》教学中实施自主学习的探索

课堂教学是学生获取知识的主渠道,教会学生如何自主学习已经成为世界各国基础教育的根本任务之一。在现代社会自主学习是学习者所必备的重要能力之一,在课堂教学模式下,让学生走自主学习之路是学会学习的有效途径。作者对本校《普通动物学》课堂教学模式下实施自主学习现状进行了分析、对比、改进,目的在于培养学生自主学习的意识,增强自主学习能力,提高学习效率。结果证明学生在自主式教学模式下积极性被充分调动,学习成绩显著提高。     

Nutrient utilization during biomass and anthocyanin accumulation in suspension cultures of wild carrot cells

The medium used for the growth of anthocyanin-accumulating wild carrot (D. carota) suspension cultures contained ammonia as a sole nitrogen source and was buffered with succinate. Ammonia was the first nutrient to be completely utilized.The uptake of carbohydrate, phosphate and succinate continued after ammonia depletion. Biomass accumulation was faster and greater when sucrose was initially present in the medium than when glucose was present. When sucrose was provided in the medium it was rapidly hydrolysed to glucose and fructose and the fructose was used preferentially to glucose. Anthocyanin accumulation was rapid after ammonia fell below 3 mM and until the pH of the medium rose from 4.5 to 5.1 or 5.2.Dedicated to Dr. Friedrich Constabel on the occasion of his 60th birthday     

基于本体的农作物种质资源平台用户模型研究

针对国家农作物种质资源平台的特点,提出了基于本体的分组分层动态用户模型构建方法。首先建立用户结点,由用户注册信息结合领域本体构建初步的分组用户模型;然后挖掘用户日志扩展、定期更新用户模型;最后利用通用本体WordNet进行同义词、不同语种的语义扩展,进一步优化用户模型。利用开源软件protégé构建了农作物种质资源核心本体,添加个人信息映射构成用户模型,计算用户对资源的兴趣度,并增加了时间因素来表明用户的兴趣随时间发生变化的情况,便于用户模型的动态更新。基于本体的分组分层动态用户模型可以给不同用户提供个性化服务,有利于提高平台的服务质量。     

一种新的丙型肝炎病毒单链丝氨酸蛋白酶基因的构建、表达与鉴定

根据丙型肝炎病毒 (HCV)丝氨酸蛋白酶晶体结构特点 ,设计并构建了一种新的单链型丝氨酸蛋白酶分子 .该分子由辅因子NS4A的核心序列、柔性连接子GSGS和NS3丝氨酸蛋白酶结构域组成 .利用设计的 3条引物 ,通过 2轮PCR获得单链丝氨酸蛋白酶基因 ,插入原核表达载体pQE30中 ,转化大肠杆菌M15 ,获得重组克隆 .经低剂量诱导和低温培养 ,目的基因获得高水平可溶表达 .以金属螯合层析法纯化的重组蛋白纯度达 95 %以上 .间接ELISA法检测 98份血清证实 ,该蛋白具有良好的抗原性和特异性 ;以重组蛋白底物NS5ab和单链丝氨酸蛋白酶建立了简便、实用的丝氨酸蛋白酶体外活性检测系统 ;以该系统观察了PMSF和EDTA对蛋白酶活性的影响 .结果表明 ,PMSF能够抑制蛋白酶的酶切活性 ,而EDTA不能抑制酶的活性 .单链型HCV丝氨酸蛋白酶的成功表达以及体外活性检测系统的建立 ,为丝氨酸蛋白酶抑制剂的研制奠定了物质基础 .     

一株粘质沙雷氏菌烈性噬菌体污水分离及特性

[目的]以粘质沙雷氏菌(8039)为宿主菌从医院污水中分离噬菌体并对其基本生物学特点进行研究.[方法]四步法污水分离噬菌体;单、双层平板噬菌斑实验筛选烈性噬菌体并观察噬菌斑形态;纯化后2%磷钨酸染色电镜观察;手工法提取噬菌体核酸酶切后琼脂糖凝胶电泳分析;利用双层平板噬菌斑实验测定最佳感染复数和完成一步生长实验.[结果]从医院污水中成功分离出粘质沙雷氏菌烈性噬菌体一株(SM701),该噬菌体有一个正多面体立体对称的头部,头径约64nm,无囊膜,有一长尾,无收缩尾鞘,尾长约143nm;基因组核酸能被双链DNA内切酶BamH Ⅰ及Hind Ⅲ切开,大小约57kb;噬菌斑圆形透明,直径1mm左右(培养12h,),边界清楚;当感染复数(multiplicity of infection,MOI)为10时,子代噬菌体滴度较高;按照一步生长实验结果绘制出一步生长曲线,可知感染宿主菌的潜伏期是约为30min,爆发期约100min,平均爆发量约为630[结论]按照国际病毒分类委员会分类标准,该噬菌体属于长尾噬菌体科(siphoviridae)烈性噬菌体,按照Bradley和Ackermann形态分类法属于B1亚群;噬菌斑与周围红色细菌生长区,颜色差异明显,非常便于观察和计数;噬菌体头部大小和形态与呼吸道病毒中的呼肠病毒和腺病毒最为接近;国内尚未见粘质沙雷氏菌噬菌体相关报道.     

BrdU抗血清制备和应用的研究——Ⅰ.高度特异的BrdU抗血清的制备与特性

半抗原BrU通过与BSA偶联制备了完全抗原,经过光吸收、SDS聚丙烯酰胺凝胶电泳和琼脂糖凝胶电泳的测定表明,核苷-蛋白质复合物符合制备的要求,每个BSA上估计大约平均有10.3个BrU。用常规免疫的方法获得兔抗BrdU的抗血清,与BrU-EA的双向扩散效价高达32。抗血清稀释128万倍时仍可见明显的ELISA阳性反应。与以前所报道的BrdU抗血清不同,该抗血清具有高水平的识别能力,已达到BrdU单克隆抗体的识别水平,无须纯化即可用于染色体及核酸的研究。     

Nutrient-split feeding strategy for dialysis cultivation of Escherichia coli

Reduction in nutrient loss during dialysis cultivation of Escherichia coli on a glycerol medium was investigated. A dialysis reactor with an inner fermentation and an outer dialysis chamber was used. Aerobic condition was maintained by limiting the glycerol feed rate to an optimum value which was estimated from the oxygen requirements for glycerol oxidation and oxygen transfer capacity of the reactor. High reduction in nutrient loss was achieved by using water as the dialyzing fluid. However, osmotic movement of water from the dialysis to the fermentation chamber was observed, and the final cell concentration was low. With a nutrient-split feeding strategy (feeding glycerol directly to the fermentation chamber and dialyzing with salt solution), glycerol loss was small, there was no osmotic flux of water to the fermentation chamber, and the cell concentration was high. Both glycerol and salt loss could be avoided, and a cell concentration of 170 g/L was obtained when the dialysis process was substituted by addition of XAD adsorbents to the dialysis chamber. Application of this nutrient-split feeding strategy to cell cultivation in a stirred tank reactor, coupled with dialysis in external dialyzer modules, resulted in low cell concentrations. (c) 1993 Wiley & Sons, Inc.     

超声波法提取剑花总皂苷工艺研究

利用超声波法,采用正交实验对剑花总皂苷提取工艺进行研究。结果表明,提取剑花总皂苷的最优条件为:粒度80目,最佳溶剂水,超声时间40 min,溶剂挥干温度80℃,料液比1:20。     

Ecological Life Table of Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae)

An ecological life table was constructed, aiming to determine the critical stages and key mortality factors of Tuta absoluta (Lepidoptera: Gelechiidae). The total population mortality of this tomato leafminer was 92.3%. During the egg stage the mortality was 58.7%, mainly due to egg inviability. A total of 8.6% egg parasitism by Trichogramma pretiosum (Riley) (Hymenoptera: Trichogrammatidae) and 5.0% egg predation by Xylocoris sp. (Heteroptera: Anthocoridae), Cycloneda sanguinea (L.) (Coleoptera: Coccinellidae) and members of the family Phlaeothripidae (Thysanoptera) was observed. The mortality of the larval stage was 33.0%. This was considered to be the critical stage as it showed the highest apparent mortality (79.8%). Larval parasitism was low (0.1%), and was only found with Goniozus nigrifemur Ashmead (Hymenoptera: Bethylidae). Predators were responsible for 79.4% of larval mortality. Therefore, their attraction to and maintenance in the target area are important management tactics to be considered for T. absoluta control. The first and second instars were considered to be the most critical, and predation by the above mentioned species was the key mortality factor. The mortality at the pupal stage was low (0.6%) and was due to malformation.     

Differences in signal transduction pathways by which platelet-derived and fibroblast growth factors activate extracellular signal-regulated kinase in differentiating oligodendrocytes

Treatment of cultured rat oligodendroglial progenitors with either platelet-derived growth factor (PDGF) or fibroblast growth factor-2 (FGF-2) activated extracellular signal regulated kinase 2 (ERK2). Activation was transient in response to PDGF, whereas it was greater and more prolonged in response to FGF-2. ERK2 activation by PDGF was preceded by a very rapid, robust and transient tyrosine phosphorylation of the PDGF receptor. Although there was consistently more activation of ERK2 in response to FGF-2 than to PDGF, immunostaining of FGF receptors 1 (FGFR1) and 2 (FGFR2) and their tyrosine phosphorylation in progenitors was very weak, and both receptors were up-regulated during differentiation to oligodendrocytes. Tyrosine phosphorylation of the FGF receptors was maximal from 15 to 60 min of treatment and was sustained for many hours. Binding of radioiodinated FGF-2 to FGFR1 was predominant in progenitors, whereas binding to FGFR2 was predominant in oligodendrocytes. ERK2 activation by PDGF was more sensitive to inhibition of tyrosine kinases, whereas ERK2 activation by FGF-2 was relatively more sensitive to inhibitors of protein kinase C. These differences in signal transduction pathways probably contribute to the different cellular responses of oligodendroglial lineage cells to PDGF and FGF-2, respectively.     

成年小鼠心肌细胞分离技术

为进行成年小鼠心肌细胞培养与收缩功能研究, 首先必须获得高产量与高质量的心肌细胞。本实验采用Langendorff装置行恒流灌流心脏, 同时监测灌流压力的变化。根据小鼠鼠龄微调灌流流速, 使初始灌流压力保持在40 mmHg。用0.05 % 单一粗制胶原酶在37 ℃条件下消化心脏, 当灌流压力下降至28 mmHg 时, 即刻终止消化。轻轻吹散心肌细胞后, 用含1 % 牛血清白蛋白的 Joklik’s MEM 培养液保存,逐步法恢复细胞外钙离子浓度。获得的心肌细胞存活率大于 70 %,复钙后耐钙心肌细胞静置 4 h,心肌细胞存活率仍能保持在(40~50) %。其中,90 %以上存活的长杆状心肌细胞无明显搏动,细胞膜表面光滑,横纹清晰,两端边缘锐利, 折光性较强, 复钙后保存4 h 或 5.0 Hz 刺激5 min 后,仍能保持正常形态。在1.0 Hz刺激条件下, 心肌细胞缩短幅度为(9.72 ±0.43) %; 2.0 Hz 刺激下为(11.28 ±0.43) %; 在5.0 Hz 刺激下, 达到(11.40 ±0.45)%。这些结果表明, 采用本方法可获得高产量与高质量的成年小鼠心肌细胞, 且易于操作, 重复性较好。     

逆相蒸发法制备茶多酚脂质体及质量评价

采用逆相蒸发法制备茶多酚脂质体并进行质量评价。通过二次回归旋转组合设计优化茶多酚脂质体制备工艺及配方,对其形态、结构、粒径分布等性质进行考察。研究结果表明,最佳配方为m（大豆卵磷脂）：m（胆固醇）=3：1、茶多酚质量浓度为7mg／mL、V（有机相）：V（水相）=4：1、磷酸盐缓冲液浓度15mmoL／L,此条件下包封率为50．37％;所制备的茶多酚脂质体形态呈圆球形或椭球形,为大单室脂质体,有效粒径为165．3nm,Zeta电位为-69．3mV。逆相蒸发法制备茶多酚脂质体方法简单可行,所制备的脂质体具有一定缓释性。     

上呼吸道感染患儿咽部病原菌分布及耐药性分析

目的了解天津滨海地区儿童上呼吸道感染病原菌情况及耐药性,以便指导临床合理用药。方法对2012年1月至2013年4月天津市滨海新区汉沽中医医院住院儿科1022例上呼吸道感染儿童咽拭子标本进行培养及鉴定。采用法国ATB自动细菌鉴定仪及MIC药敏板进行细菌鉴定和药敏试验,β-内酰胺酶试验采用头孢硝噻吩纸片法,耐甲氧西林金黄色葡萄球菌（MRSA）采用头孢西丁纸片法检测。结果检出病原菌296株,其中金黄色葡萄球菌、肺炎链球菌及流感嗜血杆菌检出率分别为13. 70%、5. 97% 、5. 19%,分列前三位。金黄色葡萄球菌对常用抗菌药物耐药率为苯唑西林30. 0%、青霉素95. 7%、红霉素80. 0%、左氧氟沙星4. 3%,MRSA占30. 0% （42/140）、;肺炎链球菌对常用抗菌药物耐药率为青霉素9. 84%、红霉素54. 1%、克林霉素52.5%、左氧氟沙星3. 3% ;流感嗜血杆菌对常用抗菌药物耐药率为氨苄西林34. 0%、阿奇霉素0%、左氧氟沙星0%,复方新诺明56. 6%、头孢呋辛3. 8%、阿莫西林/克拉维酸5. 7%。结论天津滨海地区儿童上呼吸道感染病原菌分布广泛,检出致病菌有一定的耐药率,临床应重视根据病原菌感染情况及药敏试验结果,进行耐药性监测和合理用药。     

Simultaneous saccharification and fermentation of cellulose for lactic acid production

Lactic acid production from α-cellulose by simultaneous saccharification and fermentation (SSF) was studied. The cellulose was converted in a batch SSF using cellulase enzyme Cytolase CL to produce glucose sugar andLactobacillus delbrueckii to ferment the glucose to lactic acid. The effects of temperature, pH, yeast extract loading, and lactic acid inhibition were studied to determine the optimum conditions for the batch processing. Cellulose was converted efficiently to lactic acid, and enzymatic hydrolysis was the rate controlling step in the SSF. The highest conversion rate was obtained at 46°C and pH 5.0. The observed yield of lactic acid from α-cellulose was 0.90 at 72 hours. The optimum pH of the SSF was coincident with that of enzymatic hydrolysis. The optimum temperature of the SSF was chosen as the highest temperature the microorganism could withstand. The optimum yeast extract loading was found to be 2.5 g/L. Lactic acid was observed to be inhibitory to the microorganisms’ activity.     

The dissipation of excess excitation energy in British plant species

The reversible dissipation of excitation energy in higher plants is believed to protect against light-induced damage to the photosynthetic apparatus. This dissipation is measured as the non-photochemical quenching of chlorophyll fluorescence. A method is described whereby the saturated capacity for rapidly reversible non-photochemical quenching can be compared between plant species. This method was applied to 22 common British plant species whose habitat was quantified using an index that describes shade tolerance. An association was found between occurrence in open habitats and a high capacity for non-photochemical quenching. It was found that, whilst this capacity was species dependent, it did not depend upon the conditions under which the plant was grown. The possible role of zeaxanthin as a determinant of quenching capacity was examined by measuring the contents of xanthophyll cycle carotenoids for each species. Comparing species, no correlation was seen between the saturated level of non-photochemical quenching and zeaxanthin content expressed relative to either total carotenoid or to chlorophyll. When zeaxanthin was expressed relative to the amount of xanthophyll cycle intermediates (zeaxanthin, antheraxanthin and violaxanthin), a weak correlation was seen.     

接种量对花绒寄甲繁殖的影响

释放花绒寄甲防治天牛已成为重要手段,而繁殖花绒寄甲时,接种花绒寄甲幼虫到大麦虫蛹体时,控制合适的接种量是提高花绒寄甲繁殖数量和质量的关键技术。本研究通过在替代寄主上人工接种不同数量的花绒寄甲幼虫,观察其发育情况及其子代数量、质量等指标,明确最佳接种量。结果表明：随着接种量的增加,花绒寄甲幼虫历期和蛹历期明显缩短,其中接种4头/个和6头/个,幼虫历期为13 d,蛹历期为33 d,而接种14头/个和16头/个时,幼虫历期短于12 d,蛹历期明显缩短为28~29 d。花绒寄甲结茧数随接种量增加而增加,接种数为16头/个时,结茧数最多,接近7个。花绒寄甲结茧率随着接种量增多而降低,4头/个时,结茧率最高为72.3%。接种量对花绒寄甲子代个体数量和大小均有显著影响,其中接种8头/个时,羽化数平均为4.3头,显著高于接种4头/个（羽化数平均为2.8头）,明显低于接种16头/个(羽化数平均为6.9头)。接种量为4头/个和6头/个时,子代成虫个体最大,单头重平均每头可达0.035 g,接种量为8头/个时,成虫单头重平均每头0.032 g左右,接种量达到16头/个时,单头重最轻,为0.023 g。对花绒寄甲羽化率无显著影响,7个处理下子代羽化率均较高,平均在94.4%~100%。接种量越少,更利于花绒寄甲的生长发育,当接种量为4头/个时,花绒寄甲成虫发育最好,其子代个体最大,但子代数较少。因此,利用大麦虫蛹繁育花绒寄甲种虫时,最佳接种量为4头/个,而需要规模化繁育花绒寄甲作为天敌使用时,综合考虑子代数量和质量以及经济成本,最佳接种量为8头/个。     

一步法发酵菊芋生产乙醇

利用马克斯克鲁维酵母(Kluyveromyces marxianus)YX01具有菊粉酶生产能力且乙醇发酵性能良好的特点,直接发酵菊粉生成乙醇.在摇瓶中考察了该菌株最适发酵温度,进而在2.5L发酵罐中考察了通气量和底物浓度的影响.实验结果表明:该菌株最适发酵温度为35℃;在通气量为50 mL/min和100 mL/min时菌体生长加快,发酵时间缩短,但在不通气条件下糖醇转化率明显提高;在菊粉浓度235 g/L时,发酵终点乙醇浓度达到92.2 g/L,乙醇对糖的得率为0.436,为理论值的85.5%.在此基础上,使用近海滩涂种植海水灌溉收获的菊芋为底物,以批式补料方式直接发酵菊芋干粉浓度为280 g/L的底物,发酵终点乙醇浓度为84.0 g/L,乙醇对糖的得率为0.405,为理论值的80.0%.这些研究工作,为以菊芋为原料的燃料乙醇技术开发奠定了基础.