枣果皮细胞壁代谢酶活性与抗裂果的关系

【目的】测定枣果皮细胞壁代谢酶活性,研究果皮细胞壁代谢酶活性与抗裂果的关系。【方法】以抗裂枣品种扁核酸与易裂枣品种京枣39为研究对象,测定生长过程中枣果皮不同部位细胞壁代谢酶活性,比较抗裂和易裂枣品种果皮细胞壁代谢酶活性的差异。【结果】抗裂枣品种不同时期不同部位果皮的超氧化物歧化酶(SOD)活性、过氧化物酶(POD)活性、多酚氧化酶(PPO)活性显著或极显著高于易裂枣品种,而在绿熟期不同部位抗裂品种的过氧化氢酶(CAT)活性极显著低于易裂品种。【结论】易裂品种果皮果肩阴面POD活性和PPO活性在白熟期显著高于抗裂品种,而其余时期其余部位则是抗裂品种的POD活性和PPO活性显著高于易裂品种,易裂品种果皮的梗洼、果顶、果肩阳面和果肩阴面CAT活性在绿熟期极显著高于抗裂品种,而其余时期则是抗裂品种高于易裂品种。     

Vancomycin derivatives that inhibit peptidoglycan biosynthesis without binding D-Ala-D-Ala

Vancomycin is an important drug for the treatment of Gram-positive bacterial infections. Resistance to vancomycin has begun to appear, posing a serious public health threat. Vancomycin analogs containing modified carbohydrates are very active against resistant microorganisms. Results presented here show that these carbohydrate derivatives operate by a different mechanism than vancomycin; moreover, peptide binding is not required for activity. It is proposed that carbohydrate-modified vancomycin compounds are effective against resistant bacteria because they interact directly with bacterial proteins involved in the transglycosylation step of cell wall biosynthesis. These results suggest new strategies for designing glycopeptide antibiotics that overcome bacterial resistance.     

绿斑病对夏橙叶片膜脂过氧化的影响

[目的]研究绿斑病对夏橙叶片膜脂过氧化的影响。[方法]以盆栽的2年生奥林达夏橙为试材,测定叶片膜透性、MDA、SOD、POD、CAT。[结果]轻度病叶对叶片的膜脂过氧化无显著影响,中度病叶和重度病叶显著增加了叶片中MDA含量和膜透性,降低了叶片中CATS、OD和POD含量。[结论]绿斑病藻大量寄生后引起夏橙叶片中细胞活性氧清除系统功能的降低,可能导致细胞内活性氧积累,进而引起膜脂过氧化发生和膜系统受损。     

小麦品种抗赤霉病的组织学研究

通过对四个品种穗轴的组织学和组织化学与抗扩展性关系的研究,结果表明:抗感品种健康穗轴在一些组织结构上存在着明显差异,主要表现在抗病品种的维管束导管孔径较感病品种的小,抗病品种的皮层厚壁组织和厚壁细胞壁较感病品种的厚,且差异达显著水平;抗病品种的皮层厚壁组织和厚壁细胞壁增厚的时期比感病品种的早。在受侵染的穗轴中,抗感品种在菌丝的分布和量上,以及细胞的破坏程度上有所不同。抗感品种的木质素均为具丁香素核的木质素。因此,小麦品种抗扩展性的机制之一是靠预先形成的组织结构——厚壁组织和细胞壁厚度等解剖特征来实现的。     

彩色棉纤维的超微结构观察

对白色棉、棕色棉和绿色棉纤维进行了电镜观察,结果表明:3种颜色纤维的结构由外到内依次为初生壁、次生壁和中腔.在白色纤维的超微结构中未发现染色较深的物质; 在绿色棉纤维中,纤维的次生壁内层存在大量染色深的条纹,这些条纹可能是色素沉积的结果,类似沉积的日轮;在棕色棉纤维的中腔内,存在大量染色深的物质,而且这些物质主要沉积在中腔壁上,这些染色较深的物质可能是棕色棉纤维的色素物质,同时发现棕色棉纤维具有分叉结构. 与白色纤维比较,彩色纤维表现出的品质较差,可能与纤维素含量低及色素物质的沉积有关.     

雌激素调控的绿色荧光蛋白在酵母细胞中的表达

采用绿色荧光蛋白(GFP)作为报告基因,用酵母细胞构建环境雌激素(EEH)的评价体系,可敏感、快速、方便地筛选出EEH化合物。通过分子生物学技术,将GFP基因插入到pM P 206/ERE启动子CYC 1的下游,用GFP取代L ac Z基因,并转化于酵母细胞。DNA测序发现ERE-CYC 1-GFP框架正确。对转化子进行PCR鉴定,发现有雌激素受体基因(hER cDNA)和GFP基因特异条带,说明hER cDNA和GFP已重组于酵母细胞。荧光显微镜下发现大量的绿色荧光颗粒,表明GFP基因在酵母细胞中成功表达。酵母细胞经不同浓度雌二醇作用后,与GFP表达量有剂量效应关系。与其他酵母评价体系相比,以GFP为报告基因评价EEH不需要破坏细胞壁,也不需要底物,可在96孔板中完成,这为高通量筛选EEH化合物奠定了基础。     

甘薯形态结构对茎线虫病的抗性机制

 甘薯抗茎线虫病品种鲁薯-78066和胜利百号块根周皮的木栓层细胞有4 ～ 5层，并在细胞壁上沉积有较多的木栓质。表皮接种线虫结果表明，这种形态结构可有效阻止马铃薯腐烂线虫侵入。感病品种粟子香和徐薯18的周皮不发达，只有1 ～ 2层木栓层细胞，而且木栓质极少，线虫能在24h内从表皮直接侵入。甘薯抗病和感病品种的地上茎和地下茎髓部均可受到该线虫危害。抗病品种鲁薯-78066和胜利百号在地下茎和块根顶端连接部位与感病品种粟子香和徐薯18相比较，抗病品种木质部薄壁细胞的壁厚，木质化程度高，导管数量多，线虫不能够穿过这种结构进一步扩展。抗、感品种薯块表皮的伤口有利于线虫侵入，表皮和皮层变成黑褐色，呈糠皮状，但线虫不能进入木栓形成层危害块根皮层以内的组织。     

拟南芥抗葱链格孢相关基因的差异表达分析

选取病拟南芥转基因NahG(抗病)、生态型WS-2(抗病)和Shakh-dara(感病)为材料,利用mRNA差异显示技术(DDRT-PCR)对抗、感病材料接种葱链格孢后抗性相关基因的差异表达情况进行了分析,共获得135个与拟南芥抗葱链格孢侵染相关的差异表达片段。反式Northern杂交结果表明,38个差异表达片段为阳性片段,阳性率为28.1%。同源性分析结果表明,拟南芥抗感生态型感染葱链格孢后,诱导了呼吸过程、参与细胞壁构建和蛋白质水解等相关基因的表达。其中,接种3 h诱导表达的WS-2-47序列编码含有SH3保守域的Sla1蛋白,表明拟南芥受葱链格孢侵染后可能是通过寄主细胞壁的改变来提高寄主的抗病性。     

胡萝卜抗HgCl_2变异细胞系的筛选

利用胡萝卜下胚轴愈伤组织 ,以HgCl2 为选择剂 ,通过多步正筛选法 ,获得了抗性变异细胞系 .抗性鉴定结果表明 ,在不同HgCl2 浓度的培养基上 ,抗性系的愈伤组织存活率和鲜质量增殖率均明显高过亲本系 ,抗性系的细胞膜透性也发生了变化 .对抗性系和亲本系愈伤组织进行再分化的结果表明 ,在连续 3～ 4代的分化培养之后 ,愈伤组织都能再生绿苗 .提出了该项研究在预防和治理重金属污染方面的重要意义 .     

Antiviral chemotherapy and chemoprophylaxis

Antiviral compounds have been developed for use in chemoprophylaxis and chemotherapy of a variety of infections in humans, including those caused by influenza viruses, respiratory syncytial virus, and herpesviruses. The efficacy of several of these compounds has been demonstrated in rigorously controlled trials. Advances in molecular virology have led to the identification of biochemically defined, virus-specific functions that serve as appropriate targets for the future development of antiviral compounds. Clinical investigators and practicing physicians are now confronting questions previously raised with the use of antibacterial antibiotics. These questions concern appropriate routes of administration for antiviral compounds, optimal dosage regimens, risks of long-term prophylaxis, and the emergence of resistant organisms.     

Colonial growth of Neurospora. Sorbose and enzymes alter the composition of the cell wall and induce morphological changes

L-Sorbose, an agent which induces colonial growth in Neurospora crassa, also induces structural changes in the cell wall. Acid hydrolyzates of cell walls isolated from sorbose-grown (colonial) hyphae contain more glucosamine and less glucose than do hydrolyzates of cell walls obtained from normally growing hyphae. Snail digestive juice, an agent which effects a structural change in the cell wall of N. crassa by liberating from it large quantities of glucose, has been found to induce colonial growth.     

墙面绿化降温增湿效应对人体舒适度影响的研究

为研究墙面绿化的降温增湿效应,对绿化墙面进行连续测量,并以无绿化墙面作为对照,探讨温湿度对人体舒适度的影响。结果表明:当采用墙面绿化后,绿化墙体比对照墙体室内平均温度降低0.66℃;绿化墙体内外墙面温差为1.08℃;绿化墙体外墙面比对照墙体外墙面平均温度降低0.79℃;温湿度日变化中,温度最高点出现在13∶00左右,14∶00温度有所下降,湿度最低值出现在13∶00左右,温湿度变化呈现出负相关的关系。墙面绿化一定程度上可降低THI指数,提高人体舒适度,缩小室内外温度差。     

小麦抗白粉菌初侵染过敏性反应的细胞学研究

利用细胞学方法对小麦抗白粉菌初侵染过敏性反应的研究表明，高抗寄主的反应是在病菌入侵栓活动前，由初生芽管或附着胞侵染诱导的主动防卫反应；而在中抗寄主的反应与高感寄主细胞的死亡，则是由坏死的病菌吸器诱导的；且吸器周围的寄主细胞器越少细胞坏死也越早．不论是感病还是抗病寄主细胞死亡时，细胞壁上的过氧化物酶活性均显著增强，说明它可能不是决定抗性的重要因子．     

玉米苗期对丝黑穗病抗性机制初探

以１１个不同抗性的玉米自交系和杂交种种苗为材料对玉米丝黑穗病（Ｓｐｈａｃｅｌｏｔｈｅｃａｒｅｉｌｉａｎａ）抗性机制作了初探。结果表明：冬孢子在感病的玉米材料胚芽鞘上的萌发率（１３．２３％～１８．８１％）显著高于在抗病的玉米材料胚芽鞘上的萌发率（６．６０％～７．１０％）;感病材料幼苗中维生素Ｃ（Ｖｃ）和总糖的含量分别为１４．９１～１９．７１ｍｇ／１００ｇ鲜重和４．２３％～５．９１％,显著高于抗病材料幼苗中Ｖｃ和总糖的含量（７．１８～１０．７６ｍｇ／１００ｇ鲜重、２．５２％～３．７８％）;且二者与冬孢子在胚芽鞘上的萌发率呈显著的正相关（ｒ＝０．８４７６,０．８６１２）,揭示了玉米幼苗期抗侵入的固有抗性;受玉米丝黑穗病菌侵染后,幼苗胚芽鞘内表皮在０．５３ｍｏｌ／Ｌ高渗蔗糖溶液中感病的玉米材料丧失质壁分离能力的细胞百分率高干抗病的玉米材料,高感杂交种“京黄４１７”胚芽鞘内表皮丧失质壁分离能力的细胞百分率最高（４７．４％）;抗病自交系Ｍｏ１７最低（２３％）二因此,冬孢子在玉米幼苗胚芽鞘上的萌发率,幼苗中Ｖｃ、总糖的含量,以及病菌侵入后胚芽鞘内表皮丧失质壁分离能力的细胞百分率可作为玉米早期抗丝黑穗病的鉴定指标。     

BRITTLE CULM16(BRITTLE NODE) is required for the formation of secondary cell walls in rice nodes

Plant cell walls constitute the skeletal structures of plant bodies,and thus confer lodging resistance for grain crops.While the basic cell wall synthesis machinery is relatively well established now,our understanding of how the process is regulated remains limited and fragmented.In this study,we report the identification and characterization of the novel rice(Oryza sativa L.)brittle culm16(brittle node;bc16)mutant.The brittle node phenotype of the bc16 mutant appears exclusively at nodes,and resembles the previously reported bc5 mutant.Combined histochemical staining and electron microscopy assays revealed that in the bc16 mutant,the secondary cell wall formation and thickening of node sclerenchyma tissues are seriously affected after heading.Furthermore,cell wall composition assays revealed that the bc16 mutation led to a significant reduction in cellulose and lignin contents.Using a map-based cloning approach,the bc16 locus is mapped to an approximately 1.7-Mb region of chromosome 4.Together,our findings strengthen evidence for discretely spatial differences in the secondary cell wall formation within plant bodies.     

Volatile halogenated organic compounds released to seawater from temperate marine macroalgae

Volatile halogenated organic compounds synthesized by various industrial processes are troublesome pollutants because they are persistent in terrestrial ecosystems and because they may be present in sufficient quantities to alter the natural atmospheric cycles of the halogens. Certain of these compounds, including polybromomethanes and several previously unobserved alkyl monohalides and dihalides, appear to be natural products of the marine environment. A variety of temperate marine macroalgae (the brown algae Ascophyllum nodosum and Fucus vesiculosis, the green algae Enteromorpha linza and Ulva lacta, and the red alga Gigartina stellata) not only contain volatile halogenated organic compounds but also release them to seawater at rates of nanograms to micrograms of each compound per gram of dry algae per day. The macroalgae may be an important source of bromine-containing material released to the atmosphere.     

玉米基因枪转化受体材料的选择

以4种玉米转化受体为材料,进行了基因枪转化玉米受体材料的研究。通过GUS基因的短暂表达和转Bar基因抗性绿苗分化率研究表明,预培养3～4d的玉米幼胚更适合作基因枪转化的受体材料。对转基因再生植株的PCR分析及除草剂抗性检验,证明Bar基因已整合到玉米基因组中。试验结果还表明,在转基因筛选过程中加入AgNO3,可提高抗性绿苗分化。     

彩色棉纤维发育的特性研究

棕色和绿色纤维中的色素可用HNO3/乙醇提取,提取液中的色素含量可在412 nm波长下根据吸收值的大小进行估计.在开花后15 d前后,棕色和绿色纤维中的色素已经形成和积累,并在开花后20 d色素含量达到最高值. 棕色纤维颜色发生明显加深的时期是开花后30～35 d,棕色纤维的颜色较稳定,在阳光下甚至有加深的趋势.绿色棉纤维在开花后20 d时纤维出现绿色,之后随着纤维的发育颜色逐渐加深,但在阳光下易退色.在棕色和绿色纤维中纤维素含量明显低于白色纤维,可能是由色素物质的积累所引起.在开花后15～30 d期间,白色纤维细胞的pH值呈快速下降趋势,但棕色和绿色纤维细胞的pH值下降速度比白色纤维细胞明显要慢,在这一时期pH值下降速度的快慢可能与纤维的伸长、次生壁的加厚和色素的形成有关.与白色纤维比较,棕色和绿色纤维品质较差,如:长度偏短,强度偏低,本文对其可能原因进行了探讨.     

基于Android平台的手机地图服务设计

运用结构方程模型，依据广州、深圳两地共236家制造企业数据，考量环境协同、环境监督与企业绩效之间的关系。结果表明：绿色供应链管理将社会、环境责任信息公开和公众参与融入链式管理体系中，能协同上、下游企业环境管理活动，监督环境违规行为，实现环境绩效与财务绩效的双赢。     

Loss of a callose synthase results in salicylic acid-dependent disease resistance

Plants attacked by pathogens rapidly deposit callose, a beta-1,3-glucan, at wound sites. Traditionally, this deposition is thought to reinforce the cell wall and is regarded as a defense response. Surprisingly, here we found that powdery mildew resistant 4 (pmr4), a mutant lacking pathogen-induced callose, became resistant to pathogens, rather than more susceptible. This resistance was due to mutation of a callose synthase, resulting in a loss of the induced callose response. Double-mutant analysis indicated that blocking the salicylic acid (SA) defense signaling pathway was sufficient to restore susceptibility to pmr4 mutants. Thus, callose or callose synthase negatively regulates the SA pathway.