油樟油对油樟内生真菌中活性化合物影响

YY26、YG42和YG71是从油樟中分离得到的三株内生真菌。本研究采用GC-FID、GC-MS技术,以油樟油作为诱导物,研究YY26、YG42、YG71菌株在不同培养基条件下对菌株中活性化合物1,8-桉叶油素、松油烯-4-醇、a-松油醇、r-松油烯产量的影响。结果表明:在PDB培养基中,一方面,油樟油可促进YY26、YG42菌株积累1,8-桉叶油素等物质,其中对1,8-桉叶油素的促进最强,分别提高1.41倍和1.30倍;另一方面,油樟油抑制YG71菌株中以上4种物质的积累。在察氏培养基中,油樟油对YY26、YG42及YG71菌株中4种物质的积累没有明显的促进作用。该研究为植物有用代谢产物的规模化生产提供了理论依据,有较强的实践意义。     

樟属植物叶水浸提液对油樟悬浮细胞培养的影响北大核心CSCD

以油樟、大叶樟、香樟、天竺桂4种樟属植物叶水浸提液为诱导子,添加到油樟悬浮培养系中,研究诱导子对油樟悬浮培养细胞生长及挥发性物质积累的影响。结果表明,4种樟属植物叶水浸提液对油樟悬浮细胞生长无明显影响。不同樟属植物叶水浸提液对挥发性物质影响不同。对于总的挥发性物质的积累,有促进作用的是天竺桂与香樟叶浸提液,添加量分别是4%和1%时促进作用最强,其峰面积分别为空白对照组的1.78和1.45倍;对1,8-桉叶油素的积累,有促进作用的是天竺桂叶浸提液,添加量为1%时,促进作用最强,其峰面积为空白对照组的1.46倍;对于γ-松油烯的积累,4种叶浸提液均有促进作用,大叶樟、天竺桂和香樟水提液添加量1%时促进作用最强,其峰面积分别0.39、0.27和0.32 p A,油樟水提液添加量4%时促进作用最强,其峰面积为0.27 p A(对照中无);对于α-松油醇的积累,有促进作用的是天竺桂与香樟水提液,添加量为0.25%时促进作用最强,其峰面积分别为空白对照组的1.62和1.24倍。本研究在一定程度上揭示了油樟油成分积累相关促进因子情况,为进一步研究奠定基础。     

樟属植物叶水浸提液对油樟悬浮细胞培养的影响

以油樟、大叶樟、香樟、天竺桂4种樟属植物叶水浸提液为诱导子,添加到油樟悬浮培养系中,研究诱导子对油樟悬浮培养细胞生长及挥发性物质积累的影响。结果表明,4种樟属植物叶水浸提液对油樟悬浮细胞生长无明显影响。不同樟属植物叶水浸提液对挥发性物质影响不同。对于总的挥发性物质的积累,有促进作用的是天竺桂与香樟叶浸提液,添加量分别是4%和1%时促进作用最强,其峰面积分别为空白对照组的1.78和1.45倍;对1,8-桉叶油素的积累,有促进作用的是天竺桂叶浸提液,添加量为1%时,促进作用最强,其峰面积为空白对照组的1.46倍;对于γ-松油烯的积累,4种叶浸提液均有促进作用,大叶樟、天竺桂和香樟水提液添加量1%时促进作用最强,其峰面积分别0.39、0.27和0.32 p A,油樟水提液添加量4%时促进作用最强,其峰面积为0.27 p A(对照中无);对于α-松油醇的积累,有促进作用的是天竺桂与香樟水提液,添加量为0.25%时促进作用最强,其峰面积分别为空白对照组的1.62和1.24倍。本研究在一定程度上揭示了油樟油成分积累相关促进因子情况,为进一步研究奠定基础。     

油樟内生真菌产油脂初步研究

采用GC-MS法分析78株油樟内生真菌(其中油樟根内生真菌43株,茎内生真菌11株,叶内生真菌24株)发酵产物,发现半数以上内生真菌能够产C_(16)到C_(19)的脂肪酸及相应的甲酯;利用索氏抽提法提取78株油樟内生真菌的总油脂并采用GC-MS法分析其组分,发现4株内生真菌(编号分别为YG48、YG64、YJ9、YY8)菌丝内油脂相对含量较高,种类较少,其中YG48、YY8几乎只产棕榈酸酯、亚油酸甲酯两种油脂,YG64、YJ9主要产油酸、硬脂酸、棕榈酸甲酯、油酸酰胺及硬脂酰胺。     

内生真菌对油樟挥发油积累及生理生化特性的影响

旨在研究内生真菌对油樟挥发油积累及生理生化特性的影响。以4株内生真菌(2J1、3J1、5J2、YB)作为材料,将内生真菌孢子悬浮液均匀喷洒在油樟叶片上进行处理后,提取油樟叶片中的挥发油,利用GC-MS测定挥发油中1,8-桉叶油素、α-松油醇的量。结果显示,采用2J1和3J1两种内生真菌对油樟进行处理,在处理21 d时挥发油含量达到最大值,其主要成分1,8-桉叶油素分别比对照高出201.53%、174.47%,α-松油醇高出364.14%、307.29%,且过氧化物酶(POD)、过氧化氢酶(CAT)活性及丙二醛(MOD)的含量有显著提高;由5J2和YB处理的油樟挥发油含量、POD与CAT活性以及MOD含量与对照相比差异均不显著。采用2J1和3J1处理油樟植株,能有效提高油樟挥发油的含量。     

内生黄曲霉对丹参悬浮细胞氧化酶活性的影响

目的:研究内生黄曲霉对丹参悬浮细胞次生代谢相关氧化酶活性影响,探讨丹参组织培养和次生代谢产物产生的有效诱导途径和诱导机理.方法:将丹参内生黄曲霉以活菌、发酵茵液及制作成诱导子方式分别添加到丹参悬浮细胞中,测定丹参悬浮细胞过氧化物酶、过氧化氢酶及多酚氧化酶活性.结果:不同处理方式,内生黄曲霉对丹参悬浮细胞氧化酶表达均有明显的诱导作用,其中将黄曲霉制作成诱导子对三种酶活诱导作用最明显.结论:内生黄曲霉诱导子能有效提高丹参悬浮细胞氧化酶活性.     

一氧化氮和过氧化氢在内生真菌小克银汉霉属AL4诱导子促进茅苍术细胞挥发油积累中的作用

一株属于小克银汉霉属(Cunninghamellasp.)的内生真菌(编号为AL4)制成的粗诱导子可以诱发茅苍术悬浮细胞产生多种防卫反应,包括一氧化氮(NO)、过氧化氢(H2O2)迸发和挥发油合成加强。NO专一性淬灭剂cPTIO和H2O2淬灭剂过氧化氢酶(CAT)则不仅可以分别抑制AL4粗诱导子引起的茅苍术细胞的NO和H2O2迸发,还都能部分阻断AL4粗诱导子促进茅苍术细胞挥发油合成。添加NO供体硝普钠(SNP)和H2O2都可引起茅苍术细胞中挥发油积累增加,但二者效果不同。因此暗示着NO和H2O2都是介导内生真菌AL4粗诱导子促进茅苍术悬浮细胞挥发油合成的信号分子。同时添加NO的淬灭剂cPTIO和H2O2的淬灭剂CAT并不能完全抑制AL4粗诱导子引起的茅苍术细胞挥发油积累增加,这表明内生真菌AL4粗诱导子还可以通过其他方式促进茅苍术悬浮细胞挥发油合成。     

内生真菌和诱导子对长春花悬浮细胞及生物碱合成的影响

目的:探讨内生真茵和诱导子对长春花悬浮细胞生长及生物碱合成的影响.方法:接种内生真茵与悬浮细胞的共同培养,添加诱导子到细胞培养液中对长春花悬浮细胞进行诱导处理,检测实验处理后长春花悬浮细胞各项生化指标.结果:培养液pH值上升,悬浮细胞MDA舍量增加,细胞抗氧化酶(POD、CAT)和生物碱合成的关键性酶(PAL、TDC)活性升高.生物碱产量得到提高,诱导组悬浮细胞生物碱产量达到770.36μg/gFW,共培养组生物碱产量为693.76 μg/gFW,分别比对照组提高了48%和32%.结论:真菌及其诱导子能改变长春花悬浮培养细胞的态势,导致细胞代谢结构的改变,使生物碱的产量提高.     

莪术内生真菌产β-榄香烯代谢产物的研究

从莪术内生真菌常现青霉EF03和巴恩青霉EF11的发酵产物中分离到抗癌药物β-榄香烯。在莪术的微生态系统中,由于内生真菌长期与植物相互作用,可能发生了"基因水平传递"。从而产生与宿主植物相同或相似的次生代谢产物。     

民族药马利筋内生真菌生物活性研究

药用植物内生真菌能产生与宿主相同或相似的活性物质,民族药马利筋生物活性广泛。为获得马利筋活性内生真菌资源,该研究基于“民族药-内生真菌-活性成分”的思路,考察了168株马利筋内生真菌代谢产物的生物活性,并分别采用SRB法、Griess法、PNPG法和DPPH法对内生真菌发酵液乙酸乙酯提取物进行抗肿瘤、抗炎、α-葡萄糖苷酶抑制和抗氧化等生物活性测定,对活性菌株进行ITS菌种鉴定。结果表明：（1）所筛选的168株内生真菌中有22株表现出不同程度的生物活性。其中,9株内生真菌具有显著抗肿瘤活性,其IC₅₀值在0.1～40μg·mL^-1之间;菌株MJF-53在2.5μg·mL^-1时对LPS诱导的Raw264.7释放的NO和IL-1β均具有明显的抑制作用;7株内生真菌表现出不同程度的α-葡萄糖苷酶抑制活性,其IC₅₀值在1.0～4.0 mg·mL^-1之间,其中MYF-16和MYF-55对α-葡萄糖苷酶抑制活性接近阿卡波糖;19株内生真菌具有不同程度的DPPH自由基清除活性,其中菌株MYF...     

四川宜宾三种乔木内生真菌的多样性

对四川宜宾同一生境中的油樟 [Cinnamomum longepaniculatum (Gamble) N. Chao]、香樟 [C. camphora(Linn.) Presl]和白栎(Quercus fabri Hance)三种30棵乔木根、茎、叶中的内生真菌多样性进行了研究。结果显示：三种植物中的内生真菌在属一级分类单位上都存在一定程度的多样性和器官特异性, 组丝核菌属(Phacodium Pers.)为3种植物内生真菌共有的优势属; 同时, 通过对3种植物内生真菌的比较, 发现3种植物整体及对应部     

Potential analysis of grass endophytes Neotyphodium as biocontrol agents

Many grasses in the subfamily Pooideae develop symbioses with Neotyphodium fungal endophytes, which exist widely in nature. The stably symbiotic relationship not only ensures accessible nutrients required by Neotyphodium fungal endophytes, but also significantly increases the resistance of host grasses to biological stresses through the production of secondary metabolites. Previous studies show that infected grasses with endophytic fungi have prominently enhanced resistance to pests, plant diseases, companion plants and other biological stresses. Grass endophytic fungi show remarkable resistant to at least 79 species of pests from three classes; arachnida, nematode and insecta, and to at least 22 species of pathogenic fungi. Although the biotechnological application of endophytic fungi in grass breeding for variety selection and quality improvement has progressed well, opportunities remain for further exploring the use of fungal endophytes among different host grasses coupled with the examination of genetic stability of Neotyphodium in novel host grasses. In the future application of endophytic fungi as a bio-control method, researchers should not only consider specificities of host grasses, but also need to have comprehensive analysis and knowledge about the mutual relationships among grasses, endophytic fungi and ecological environments, which will help use endophytic fungi to better serve humanity.     

禾草内生真菌作为生防因子的潜力分析

早熟禾亚科多种禾草可与Neotyphodium内生真菌形成禾草-内生真菌共生体, 这种植物-微生物共生体性状较为稳定, 且在自然界中广泛存在。禾草-内生真菌共生体稳定的互利共生关系不但保证了内生真菌所需的全部营养物质, 而且共生体产生的次生代谢物又可显著提高宿主禾草对生物胁迫的抗逆性。众多研究表明, 内生真菌的侵染可显著提高宿主禾草对虫害、病害及伴生植物等多种生物胁迫的抗性。据不完全统计, 禾草内生真菌对蛛形纲、线虫纲、昆虫纲3个纲至少79个种的害虫表现出较明显的抗性, 对至少22个种的病原真菌表现出明显的抗性。尽管利用内生真菌进行禾草品种选育及其品质改良的技术日趋成熟, 但是内生真菌在不同宿主禾草之间高效的替代转化技术, 及其在宿主体内遗传的稳定性仍有待于进一步深入探索。研究者把禾草内生真菌作为生防手段, 在未来的应用过程中不应只考虑其与宿主禾草之间的共生特异性, 而应更全面地分析禾草-内生真菌-生态环境之间的相互关系, 让内生真菌更好地为人类服务。     

Fungal endophytes and bioprospecting

Horizontally transmitted fungal endophytes are an ecological group of fungi, mostly belonging to the Ascomycota, that reside in the aerial tissues and roots of plants without inducing any visual symptoms of their presence. These fungi appear to have a capacity to produce an array of secondary metabolites exhibiting a variety of biological activity. Although the ability of fungi to produce unique bioactive metabolites is well known, endophytes have not been exploited, perhaps because we are only beginning to understand their distribution and biology. This review emphasizes the need to routinely include endophytic fungi in the screening of organisms for bioactive metabolites and novel drugs; it also underscores the need to use information obtained concerning fungal secondary metabolite production from other groups of fungi for a targeted screening approach.     

A potential antioxidant resource: Endophytic fungi from medicinal plants

Medicinal plants and their endophytes are important resources for discovery of natural products. Several previous studies have found a positive correlation between total antioxidant capacity (TAC) and total phenolic content (TPC) of many medicinal plant extracts. However, no information is available on whether such a relationship also exists in their endophytic fungal metabolites. We investigated the relationship between TAC and TPC for 292 morphologically distinct endophytic fungi isolated from 29 traditional Chinese medicinal plants. The antioxidant capacities of the endophytic fungal cultures were significantly correlated with their total phenolic contents, suggesting that phenolics were also the major antioxidant constituents of the endophytes. Some of the endophytes were found to produce metabolites possessing strong antioxidant activities. Several bioactive constituents from the fungal cultures and host plant extracts were identified. This investigation reveals that the metabolites produced by a wide diversity of endophytic fungi in culture can be a potential source of novel natural antioxidants.     

Effects of sabinene and γ-terpinene from coastal redwood leaves acting singly or in mixtures on the growth of some of their fungus endophytes

Sabinene and γ-terpinene were assayed in vitro acting singly or in mixtures in the gaseous state on the following redwood endophytes: Botrytis cinerea, Cryptosporiopsis abietina, Pestalotiopsis funerea, Phomopsis occulta, Pleuroplaconema sp. and Seiridium juniperi. The hypothesis that these redwood monoterpenes were acting additively or synergistically in inhibiting the growth on leaf endophytes was tested. Dose-response curves were obtained for each endophyte growing under five concentrations of both sabinene and γ-terpinene. Three mixtures of different ratios were assayed keeping constant 0.25 mg of monoterpenes per ml air. Either acting singly or in mixtures sabinene and γ-terpinene were inhibitory to all fungi, but their effect varied according to species. Both compounds had similar effects acting singly on each endophyte with doses from 0.0625 to 0.25 mg ml air⁻¹. With doses of 1.6667 mg ml air⁻¹ of either monoterpene, S. juniperi was mildly inhibited by sabinene and strongly inhibited by γ-terpinene, but other species were strongly and equally inhibited by both compounds. Sabinene: γ-terpinene mixtures of 1:3, 1:1 and 3:1 ratios were equally inhibitory for each species. Results suggest that when these compounds co-occur, they act additively on leaf endophytic fungi.     

茅苍术挥发油对三种内生真菌及七种外源真菌的抑菌活性

为了研究宿主植物次级代谢产物对内生真菌生长的抑制作用,以药用植物茅苍术及其内生真菌为材料,采用有机溶剂萃取法提取茅苍术挥发油,应用滤纸片扩散法和平板涂布法研究茅苍术挥发油对茅苍术内生真菌及其他外源真菌的抑菌作用.结果表明: 挥发油对3种内生真菌生长具有抑制作用;对酵母、水霉有很强的抑菌活性;对根霉、犁头霉抑菌作用不明显;对绿色木霉、黑曲霉的产孢具有抑制作用;对疫霉生长无抑制作用.在高浓度挥发油胁迫下,内生真菌菌丝分支增多,分支间距离变短,气生菌丝生长受到抑制.两种内生真菌对挥发油具有代谢转化能力,降低了其主要成分的含量.表明茅苍术挥发油对内生真菌生长具有限制作用,但内生真菌能够通过自身分解代谢适应茅苍术挥发油.     

Bioactive secondary metabolites produced by microorganisms associated with plants

In the past few decades groups of scientists have focused their study on relatively new microorganisms called endophytes. By definition these microorganisms, mostly fungi and bacteria, colonise the intercellular spaces of the plant tissues. The mutual relationship between endophytic microorganisms and their host plants, taxanomy and ecology of endophytes are being studied. Some of these microorganisms produce bioactive secondary metabolites that may be involved in a host-endophyte relationship. Recently, many endophytic bioactive metabolites, known as well as new substances, possesing a wide variety of biological activities as antibiotic, antitumor, antiinflammatory, antioxidant, etc. have been identified. The microorganisms such as endophytes may be very interesting for biotechnological production of bioactive substances as medicinally important agents. Therefore the aim of this review is to briefly characterize endophytes and summarize the structuraly different bioactive secondary metabolites produced by endophytic microorganisms as well as microbial sources of these metabolites and their host plants.     

Endophytic fungi from <Emphasis Type="Italic">Nerium oleander</Emphasis> L (Apocynaceae): main constituents and antioxidant activity

Diverse endophytic fungi exist within plant aerial tissues, with a global estimate of up to a million undescribed species. These endophytes constitute a rich bio-resource for exploration to discover new natural products. Here we investigate fungal endophytes associated with a medicinal plant, Nerium oleander L. (Apocynaceae). A total of 42 endophytic fungal strains were isolated from the host plant. Total antioxidant capacity, xanthine oxidase inhibitory activity, antimicrobial activity, and total phenolic content (TPC) were evaluated for 16 representative fungal cultures grown in improved Czapek’s broth and for the host plant. The total antioxidant capacities and phenolic contents of the fungal cultures ranged from 9.59 to 150.79 μmol trolox/100 mL culture, and from 0.52 to 13.95 mg gallic acid/100 mL culture, respectively. The fungal culture of an endophytic strain Chaetomium sp. showed the strongest antioxidant capacity, contained the highest level of phenolics, and to some extent inhibited xanthine oxidase activity with an IC₅₀ value of 109.8 μg/mL. A significant positive correlation was found between antioxidant capacity and TPC in the tested samples. Most of the endophytic fungal cultures tested have a wide range of antimicrobial activities, which were not very strong, but much better than those of the host plant. The major bioactive constituents of the fungal cultures were investigated using LC-ESI-MS and GC-MS, and preliminary identification detected phenolics (e.g. phenolic acids and their derivatives, flavonoids) and volatile and aliphatic compounds. This study shows that the endophytic fungi isolated from N. oleander can be a potential antioxidant resource.