Infection with Phloem Limited Abutilon Mosaic Virus Causes Localized Carbohydrate Accumulation in Leaves of Abutilon striatum: Relationships to Symptom Development and Effects on Chlorophyll Fluorescence Quenching During Photosynthetic Induction

Abstract: Infection with phloem limited Abutilon Mosaic Virus caused localized carbohydrate accumulation (high levels of starch, sucrose, and hexoses) in leaves of Abutilon striatum during early symptom development. In mature leaves with attenuated symptoms, tissues showing faint vein-clearing had markedly higher carbohydrate contents than uniformly green areas of the same leaf. A similar pattern of carbohydrate accumulation was found in pale-green mosaics in mature leaves with overt symptoms when compared to green-islands of the same leaf, but overnight carbohydrate loses were comparable to controls. Because leaves with attenuated symptoms showed no further symptom development whereas the pale-green mosaics became yellow and eventually necrotic in leaves with overt symptoms, it seems unlikely that carbohydrate accumulation following impaired translocation was responsible for symptom expression. High carbohydrate status in leaves with attenuated symptoms had little effect on nonphotochemical quenching during early stages of photosynthetic induction. In leaves with overt symptoms, areas of high carbohydrate status with pale-green mosaics showed markedly slower nonphotochemical quenching. Early symptom areas of young leaves, and advanced symptom areas of mature leaves had low starch contents but were otherwise similar to controls in carbohydrate status. Impaired nonphotochemical quenching in these tissues tended to reflect the state of symptom development, rather than carbohydrate status. Plants with overt symptoms grew about half as fast as plants with attenuated symptoms.     

Chlorophyll Fluorescence Quenching During Photosynthetic Induction in Leaves of Abutilon striatum Dicks. Infected with Abutilon Mosaic Virus,Observed with a Field-Portable Imaging System

A portable Chi fluorescence imaging system was used to characterise nonuniform Chi fluorescence quenching in Abutilon striatum leaves infected with phloem-localised abutilon mosaic virus. The instrument was used to observe fluorescence emission at intervals during induction transients, and to map nonphotochemical quenching during saturating pulses applied in the course of these transients. Two symptom types were distinguished: yellow vein-associated motifs that showed lower maximum Chi fluorescence than nearby green tissues, but virtually zero nonphotochemical quenching, and vein-defined mosaics (pale green) that initially showed normal maximum Chi fluorescence but strongly impaired nonphotochemical quenching. Mature vein-defined mosaics (yellow to white areas) resembled vein-associated symptoms with zero nonphotochemical quenching. Islands of apparently healthy green tissue enclosed by mosaic symptoms showed slower nonphotochemical quenching than controls. Possible effects of localised carbohydrate accumulation, thought to follow from infection by the phloem-limited virus, on photosynthetic processes as well as the synthesis and stability of chloroplast protein complexes, are discussed in the context of symptom development.     

六种藜科植物提取物对植物病原菌的抑制活性

研究了角果藜（ Ceratocarpus arenarius）、盐穗木（ Halostachys caspica）、里海盐爪爪（ Kalidium caspicum） 、叉毛蓬（ Petrosimonia sibirica ）、盐角草（ Salicornia europaea ）和小叶碱蓬 （ Suaeda microphylla ）等六种新疆藜科植物提取物及其不同极性萃取部分对根癌土壤杆菌（Agrobacterium tumefaciens ）、黄瓜角斑病菌（P Pseudomonas lachrymarts）、番茄疮痂病菌（ Xanthomonas vesicatoria ） 等植物病原细菌以及杨树溃疡病菌（ Botryosphaeria dothidea ）、棉花枯萎病菌（Fusarium oxysporum f. sp. vasinfectum ）、稻纹枯病菌（Rhizoctonia solani）等病原真菌的抑制活性。结果显示角果藜、叉毛蓬和盐角草乙醇粗提物表现出一定抗细菌活性,其中以叉毛蓬和盐角草提取物对黄瓜角斑病菌的抑制活性最强。多数植物提取物及其不同极性萃取部分对杨树溃疡病菌表现出强的抑制活性。抗真菌活性成分主要存在于供试植物的石油醚、氯仿和正丁醇萃取部分中,提示活性成分为极性中等的化合物。角果藜和盐角草乙醇粗提物及其不同极性萃取部分对供试真菌有较好的抑制活性。     

不同蕨类植物提取物乙酰胆碱酯酶抑制活性的评价

为对采自浙江天目山的40种蕨类植物乙醇提取物进行乙酰胆碱酯酶抑制活性研究。本文采用乙酰胆碱酯酶抑制活性筛选模型。结果表明：在供试质量浓度在1mg／mL时,40种植物的乙醇提取物均具有明显的乙酰胆碱酯酶抑制活性,其中密羽贯众、野雉尾金粉蕨和狗脊等13种蕨类植物表现出较强的抑制活性,抑制率均大于90％,其余大部分植物的抑制率均大于60％。而在供试质量浓度在0．025mg／mL时,只有少数植物表现出较高的乙酰胆碱酯酶抑制活性,其中狭顶鳞毛蕨的抑制率为62．63％±3．72％,蜈松草的抑制率为48．01％±2．87％,其余大部分植物的抑制活性均小于40％,甚至有些植物提取物不仅对乙酰胆碱酯酶没有抑制活性,反而表现出一定的增强作用。     

77种植物提取物对植物病原菌的生长抑制作用

以稻瘟病菌(Pyricularia grisea),水稻恶苗病菌(Fusarium moniliforme),玉米大斑病菌(Exserohilum turci-cum)等12种植物病原菌为供试菌种,采用生长速率法对77种植物的95%乙醇提取物在200μg/mL下进行室内抑菌试验。结果表明有15种植物提取物对植物病原菌有抑制作用,其中华山姜、硬骨藤、龙舌兰、红蒜、大花哥纳香、海南草珊瑚对至少一种菌的抑制率在50%以上,版纳青梅、大果巴戟、华山姜等8种植物提取物对至少三种病原菌均有不同程度的抑制作用。红蒜提取物对百合炭疽病菌、海南草珊瑚提取物对番茄灰霉病菌,以及龙舌兰提取物对玉米大斑病菌的抑制率分别为61.4%、70.7%、76.6%,与阳性对照抑制率相比效果明显。     

Inhibitory Activity of Honeysuckle Extracts against Influenza A Virus In Vitro and In Vivo

Virologica Sinica - Honeysuckle has been used in the treatment of influenza virus infection for thousands of years in China. However, its main active components and the functional mechanisms remain...     

博落回、虎杖和黄芩提取物对植物病原菌的抑制作用

研究了博落回(Macleaya cordata)、虎杖(Reynoutria japonica)和黄芩(Scutellaria baicalensis)提取物对三种植物病原细菌和六种病原真菌的抑制作用.结果显示:虎杖提取物对根癌土壤杆菌和番茄疮痂病菌表现出较强的抗细菌活性;博落回提取物表现出较强的抗真菌活性,对供试真菌的半抑制浓度(IC50)在0.04～0.76mg/mL之间.     

虎杖提取物对弹性蛋白酶的抑制作用研究

本文主要研究了虎杖提取物对弹性蛋白酶的抑制作用。实验利用热水浸渍法提取虎杖得到粗提取物1(CE1),聚酰胺柱层析后得到粗提取物2(CE2),并进行一系列的定性及定量分析。分别用紫外分光光度法和荧光光谱法研究了提取物对弹性蛋白酶的抑制作用和荧光猝灭作用。实验结果表明CE1和CE2中均含有虎杖苷,含量分别为41.01%和69.57%。CE1、CE2和虎杖苷对弹性蛋白酶有一定的抑制作用,当浓度为2.0 mg/mL时,它们对弹性蛋白酶的抑制率分别为53.56%、61.27%和82.53%。CE1、CE2和虎杖苷对弹性蛋白酶均有明显的内源荧光猝灭作用,当浓度为0.1 mg/mL时,荧光猝灭率分别为70.38%、72.90%和75.99%。     

三种苔藓植物提取物对植物病原菌的抑菌性研究

以立枯丝核菌(Rhizoctoniasolani)、棉花枯萎病菌(Fusariumoxysporum)、苹果轮纹病菌(Physalosporapiricolanosa)、草莓灰霉病菌(Botrytiscinerea)四种植物病原菌为供试病原菌,对大镰刀藓Drepanocladusexannulatus、锐尖匍灯藓Plagiomniumacutum和疣小金发藓Pogonatumurnigerum三种藓类醇提液进行抑菌活性筛选,结果表明,大镰刀藓提取液对立枯丝核菌有较好的抑制作用,对立枯丝核菌的EC50为0.878mg/mL;而锐尖匍灯藓的提取液对立枯丝核菌的生长却有促进作用。     

An Efficient Microinoculation Procedure to Study Plant Virus Multiplication at Predetermined Individual Infection Sites on the Leaves

The microinoculation procedure (inoculated are 0.02—0.05 mm² was carried out using the very thin tip of a stretched Pasteur pipette. It was dipped in a 500 μg/ml suspension of purified TMV, brought into contact with the upper epidermis of the leaf which had been dusted With an abrasive and rotated twice without actually pricking the leaf tissue. Five minutes later, the excess abrasive and virus were removed by rinsing the leaves under water. The procedure was applied to several tobacco-TMV combinations. It induced the formation of single local lesions with over 90% efficiency on hypersensitively reacting hosts. Comparable efficiencies were obtained with systemically reacting hosts, as evidenced by a radiochemical procedure coupled with indirect ELISA (KONATE and FRITIG 1983). It was found that residual virus originating from the inoculum was negligible and could casily be distinguished form newly synthesized virus, even shortly after the microinoculation. This makes it possible to measure the rates of virus cell-to-cell spread and of virus multiplication at various times after inoculation and at various distances form the points of virus entry. These approadies can be extended to the comparison between differently reacting hosts and to the study of interference between different viruses or different virus strains.     

植物提取物对霉菌的抑制作用

以生活环境中常见的霉菌(青霉、米曲霉和黑曲霉)为试验菌,选取可能对其有抑制作用的植物,通过对其有机成分进行粗提,用滤纸片法筛选对上述霉菌有抑制效果的植物。经查阅相关文献,得备选植物共25种,试验后发现黄连抑制作用最强,其次是丁香和黄芩,最后对这3种中草药植物的最低抑菌浓度进行定量测定。     

20种植物提取物抑制植物病原菌活性研究

以小麦纹枯病菌(Rhizoctonia cerealis)、番茄灰霉病菌(Alternaria solani)这两种植物病原真菌为供试菌,对采自江西省吉安市的20种植物提取物的抑制菌丝生长活性及孢子萌发进行测定.结果表明,在供试质量浓度为1 mg/mL时,黄花草木樨乙醇提取物的乙酸乙酯萃取部分抑菌效果最好,对小麦纹枯病菌和番茄灰霉病菌两种菌的抑制率均达100%;窃衣、小白酒草、羊蹄和车前草的抑制作用次之,对两种菌的抑制率均大于80%;单从对一种病原菌的抑制作用看,还有黄荆对小麦纹枯病菌率为100%,空心莲子草、窃衣、小白酒草和鬼针草对番茄灰霉病菌的抑制率为100%,但是,这20种供试植物的石油醚相和水相萃取物对两种病原真菌的抑制效果均不强.抑制病原菌孢子萌发亦得到类似结果.以上结果提示植物抑菌活性成分主要存在于乙酸乙酯萃取部分,黄花草木樨、窃衣、小白酒草等的提取物作为植物源杀菌剂值得进一步研究.     

Xanthine Oxidase Activity in the Susceptible and Hypersensitive Responses of Tobacco Leaves to Tobacco Mosaic Virus Infection

A superoxide-producing xanthine oxidoreductase was isolated and quantified after polyacrylamide disc gel electrophoresis of tobacco leaf extracts. The results obtained indicate that, like uricase activity, a slight increase in tobacco xanthine oxidase activity takes place in the susceptible interaction with tobacco mosaic virus (TMV). In contrast, out of three hypersensitive tobacco cultivars tested, only two showed the same slight increase m activity during the late stage of hypersensitive response.
Allopurinol [4-hydroxypyrazolo(3,4-d)pyrimidine] a specific and potent in vitro and in vivo inhibitor of xanthine oxidoreductase, applied to tobacco plants by root absorption, starting about 8 days before the inoculation, did not affect the hypersensitive response but weakened the hypersensitivity-linked virus localization and promoted the movement of a certain amount of TMV particles and/or virus related material from necrotic lesions which induced systemic necrotic symptoms in uninoculated leaves. However, due to the inefficacy of allopurinol in preventing necrotic lesion development, all results are consistent with the hypothesis that xanthine oxidoreductase, the first enzyme in purine oxidative degradation, plays only a secondary role during induction of primary hypersensitive cell death in TMV infected tobacco leaves.