长枝木霉菌株T05抑菌活性与拮抗机制

研究了长枝木霉(Trichoderma longibrachiatum)菌株T05的抑菌活性与拮抗机制,包括菌落的对峙培养试验,挥发性物质和4种分生孢子提取物的抑菌试验。对峙培养试验表明,T05对灰霉病菌(灰葡萄孢(Botrytis cinerea))和杨树烂皮病菌(污黑腐皮壳(Valsa sordida))均表现出很强的抑菌活性,抑菌率分别高达88.4%和91.9%;其产生的挥发性物质对B.cinerea有较强的抑菌活性,抑菌率高达91.9%,而对V.sordida抑菌作用较弱,最高为37.2%;甲醇、乙醇、Na OH、超声波破碎水抽提4种分生孢子提取物对V.sordida的抑菌试验表明,Na OH提取物100倍液的抑菌率最高,为76.3%,而甲醇和乙醇提取物的抑菌效果稍弱,超声波水法的提取物仅对病菌有微弱的抑制作用。     

内生细菌ZJ1105的分离及其抗真菌机制研究

按照常规方法从5种常见的园艺植物茎、叶组织中共分离获得101株内生细菌,其中36株的代谢产物至少对1种或几种植物病原真菌的生长有明显的抑制作用,菌株ZJ1105的抑制活性最强。根据菌落特征、显微观察、生理生化反应和16s rDNA分析结果,初步鉴定ZJ1105为不动杆菌(Acinetobacter sp.)。进一步的研究表明,该菌的活性成分在正丁醇萃取部分,其作用机制可能与破坏真菌的细胞壁有关。     

独活提取物抑制柑橘病原真菌活性成分的分离与鉴定

【目的】为了探明独活抑制柑橘病原真菌的活性成分。【方法】采用生长速率法、溶剂萃取、硅胶柱层析、气相色谱-质谱联用(GC-MS)等方法研究独活乙醇提取物对3种柑橘贮藏病害病原真菌的抑菌作用,并分离和鉴定其抑菌活性成分。【结果】独活乙醇提取物中含有高效抑制柑橘炭疽菌的活性物质。GC-MS鉴定B2组分中含有4种香豆素类化合物—异佛手柑内酯、牛防风素、茴芹内酯、异茴芹内酯。异佛手柑内酯、茴芹内酯、异茴芹内酯3种化合物对柑橘炭疽菌的EC50在45 mg.L-1左右,其中茴芹内酯的抑制活性最好,其EC50为41.521 6 mg.L-1。显微观察发现,茴芹内酯处理导致柑橘炭疽菌菌丝体分支增多、畸形,部分隔膜消失等变化。【结论】异佛手柑内酯、茴芹内酯、异茴芹内酯为独活抑制柑橘病原真菌的主要活性物质。     

Phytochemical and antifungal studies on Terminalia mollis and Terminalia brachystemma

Phytochemical investigation of the stem bark of Terminalia mollis afforded friedelin (1), catechin with epicatechin (2), gallocatechin with epigallocatechin (3) and 3-O-methylellagic acid 4'-O-α-rhamnopyranoside (4). Arjunolic acid with 2α, 3β, 23-trihydroxy-urs-12-en-28-oic acid (5), 2α-hydroxyursolic acid (6), gallic acid (7), chebulanin (8) and 2'-O-galloylvitexin (9) were isolated from the leaf. Chebulanin (8), betulinic acid (10), ursolic acid (11), catechin (12), isoorientin (13), orientin (14), isovitexin (15) and punicalagin (16) were isolated from Terminalia brachystemma leaf. The first full unambiguous NMR assignments for (4) and (8), and revised assignments for (9), are reported. Compound (16) showed good activity against three Candida species.     

Antifungal activity of Agapanthus africanus extractives

The ethanolic extract of the rhizomes of Agapanthus africanus showed antifungal activity. In bioassay guided fractionation, n-butanol fraction exhibited significant activity against human pathogens. A saponin, (25R)-spirost-7-en-2alpha,3beta,5alpha-triol-3-O-[alpha-L-rhamnopyranosyl(1-->2)-[beta-D-galactopyranosyl (1-->3)] beta-D-glucopyranoside (1), responsible for the antifungal activity and having MIC value of 15.6 microg/ml against Trychophyton mentagrophytes and Sporothrix schenekii, was isolated and identified as active constituent of the plant.     

Antibacterial and antifungal activities of Angiopteris evecta

The leaves, stem bark, stem heart wood, root and tubers of Angiopteris evecta were successively extracted with petrol, dichloromethane, ethyl acetate, butanol and methanol. All the fractions exhibited a wider spectrum of antibacterial activity. The dichloromethane and ethyl acetate fractions of the leaves and stem bark were particularly good and were the only fractions exhibiting antifungal activity. All fractions of the tuber with the exception of petrol, exhibited very good antibacterial activity.     

板栗疫病菌的培养性状研究及药剂筛选

[目的]为了解板栗疫病病原性状及各种杀菌剂对该病的防治效果。[方法]测定了不同温度和不同农药对板栗疫病菌菌丝生长的影响。[结果]板栗疫病菌的生长温度为8~35℃,最适生长温度为23~26℃;在供试的5种杀菌剂中,以浓度50%多菌灵WP和浓度50%退菌特WP的500~1 000倍稀释液对板栗疫病菌的抑菌效果最为明显。[结论]浓度50%多菌灵WP和浓度50%退菌特WP可望用于该病害的防治实践。     

印楝种仁粗提物对植物病原菌的抑制作用研究

[目的]研究无公害生物农药的抑菌效果。[方法]通过室内毒力测定,比较印楝种仁的常规溶剂萃取物和超临界CO2萃取物对供试的8种病原菌的抑制作用。[结果]印楝常规溶剂萃取物和超临界CO2萃取物对8种病原菌均有良好的抑制作用,尤其对辣椒疫霉、茄子枯萎、番木瓜炭疽、西瓜蔓枯、香蕉黑星作用明显,其中超临界CO2萃取物抑菌效果比常规溶剂萃取物好,具有萃取时间较短,活性较高,对中、低分子量和非极性化合物有较强的亲和力等特点,但萃取率较常规溶剂低,提取时所耗的原材料多。[结论]印楝种仁超临界CO2萃取物对植物病原菌抑制效果较好,但在实际应用中要根据生产效益来选择适合的萃取物。     

21种中草药醇提物抑菌活性研究

[目的]开发理想的植物源杀菌剂。[方法]以链格孢菌和灰霉菌为供试菌种,用生长速率法分别对21种中草药乙醇提取物进行室内抑菌活性测试。[结果]用提取物质量浓度为0.02 g/ml进行初次筛选时,丁香、牵牛子等7种提取物对灰霉菌抑菌率在70.00%以上;丁香、牵牛子等7种提取物对链格孢菌菌丝生长的抑制率达50.00%以上;用提取物质量浓度0.01 g/ml进行二次筛选,丁香、细辛、辛夷和苦参4种提取物对灰霉菌的抑菌率分别为100%、69.67%、62.52%、62.21%,与多菌灵相当;丁香、黄连、苦参、高良姜、细辛5种提取物对链格孢菌抑菌活性分别为100%、72.60%6、7.30%、63.90%、54.30%,均明显高于多菌灵6.90%抑菌率。[结论]丁香、苦参、细辛对两种真菌的抑制作用较明显。     

海漆不同提取方法提取物对3种植物病菌的抑制作用

以红树植物海漆不同提取方法的提取物对香蕉炭疽病、芒果炭疽病、香蕉枯萎病进行了室内抑菌活性试验。结果表明:4种提取方法的提取物对供试的病原菌有不同的抑制作用,其中溶剂浸渍法最好,索氏提取法和超临界CO2萃取法效果较差。