中国枝孢菌属的分类研究XII.露珠草上一新种

报道寄生在柳叶菜科(Onagraceae)南方露珠草(Circaea mollis Sieb．Et Zuu.)上枝孢菌属一新种：露珠草枝孢Cladosprium circaeae Y．Qin et Z.Y．Zhang sp. Nov.。枝孢菌属真菌在柳叶菜科是首次报道。文中为新种提供了拉丁文描述和附图。模式标本保藏于云南农业大学真菌标本室(MHYAU)。     

分离自蜻蜒虫草的拟青霉属一新种

本文描述了拟青霉属(Paecilomyces)一新种—蜻蜓拟青霉(P. odonatae),该菌分离自蜻蜓虫草(Cordyceps odonatae),与其它种的典型区别特征是它具有拟青霉型产孢结构,产椭圆形链状排列的分生孢子和枝顶孢霉型产孢结构,产柱状粘成团排列的分生孢子.     

荔枝核的五个苷类成分

通过溶剂分部和多种色谱分离,从荔枝(Litchi chinensis Sonn.)核中得到5个苷类成分。经光谱分析及与文献数据对照,分别鉴定为(-)-松脂素4-O-β- D-吡喃葡萄糖苷 (1)、苯乙基β- D-吡喃葡萄糖苷 (2)、乙基β- D-吡喃葡萄糖苷 (3)、乙基α- D-吡喃葡萄糖苷 (4)和胞苷 (5)。它们均为首次从荔枝核中分离得到。     

白木香果实化学成分研究

运用柱色谱技术从白木香(Aquilaria sinensis (Lour.) Gilg)果实中分离得到7个化合物,经波谱解析和理化性质分别鉴定为: 3-吲哚甲酸(1)、6-羟基-2-[2-(4-羟基苯基)乙基]色原酮(2)、芫花素(3)、4', 5-二羟基-3',7-二甲氧基黄酮(4)、洋芹素-7,4'-二甲醚(5)、 β-谷甾醇(6)和胡萝卜苷(7)。其中化合物1为首次从瑞香科沉香属植物中分离得到。     

Acremonium hansfordii,一中国新记录种及其抗植物病原真菌活性的研究

Acremonium hansfordii是中国一新记录种,在PDA平板上对多种植物病原真菌有很强的抑制作用。通过95%乙醇提取、YPR-Ⅱ型大孔吸附树脂吸附、乙酸乙酯萃取、沸点30-60℃石油醚沉淀等方法从Acremonium hansfordii菌丝体分离纯化出具有抗植物病原真菌活性的化合物枝顶孢素(acremonin),并得到结晶。Acremonin对多种植物病原真菌都有抑制作用,其中对苹果腐烂病菌Valsa mali的IC50为0.095μg/mL,热稳定,121℃灭菌30min抑菌活性保留91.9%,pH4-9稳定。     

中国枝孢菌属的分类研究XIII．枝孢菌属二新种

报道枝孢菌属Cladosporium Link二新种：马兜铃枝孢 C. aristolochiae H. Zhang etZ. Y. Zhang sp nov.寄生在马兜铃科Aristolochiaccae 的南川马兜铃．Aristolochiakwargsiensis Chun et How ex C.F. Liang叶上,结香枝孢 Cladosporium edgeworthiae H.Zhang,et Z. Y．Zhang sp nov．寄生在瑞香科Thymelacaccac的结香Edgeworthiachrysantha Lindl．叶上。枝孢菌属真菌在马兜铃科是首次报道,瑞香科上的荛花异孢 Heterosporium wikstro—emiae Sawada(裸名),其分生孢子圆柱形,0-3个隔膜,表面粗糙,14～44×5～6μm,比本种大而宽,易于区别。文中为新种提供了拉丁文简介并附图。模式标本保藏于云南农业大学真菌标本室(MHYAU)。     

中国枝孢属的分类研究XXV.*生于蕨类植物上的二新种

报告了寄生于蕨类植物上的枝孢属Cladosporium二新种：扇蕨枝孢C．Neocheiro－pteridis和巢蕨枝孢C．Neottopteridis。新种提供了拉丁文和中文描述及形态图。模式标本收藏于云南农业大学真菌标本室（MHYAU）。     

中国枝孢属研究XXVI.*

本文报道枝孢属Cladosporium 的二个新种: 忍冬生枝孢C. lonicericola和山菅兰生枝孢C. dianellicola。新种提供了拉丁文简介、中文描述及形态图。模式标本收藏于云南农业大学真菌标本室(MHYAU)。     

红树林植物瓶花木中的细胞毒活性成分(Ⅱ)

从红树林树植物瓶花木(Scyphiphora hydrophyllacea Gaertn. f.)的乙醇提取物中分离得到5个化合物,通过波谱分析,鉴定其结构分别为:shanzhigenin methyl ester (1)、1-epishanzhigenin methyl ester (2)、山柰酚 (3)、芹菜素 (4)和 5,7,2'-trihydroxy-3,6,8,4',5'-pentamethoxyflavone (5)。以上化合物均为首次从瓶花木中分离得到。细胞毒活性测试结果表明,化合物1和2的混合物对人肝癌细胞(SMMC-7721)的增殖有较强的生长抑制活性。     

海南产木薯茎化学成分研究

从木薯(Manihot esculenta Crantz)茎的乙醇提取物中分离得到6个化合物,通过波谱分析,分别鉴定为呋喃(1)、肥牛木素(2)、3-吲哚甲酸(3)、3,9,13-megastigmanetriol (4)、穗花杉双黄酮(5)、yucalexin P-21 (6),其中化合物1~5为首次从该植物中分离得到。用滤纸片琼脂扩散法测定了这些化合物的抗菌活性,结果表明化合物1、3、4和6对耐甲氧西林金黄色葡萄球菌(MRSA)和金黄色葡萄球菌均有抑制作用。     

Fungal ovicidal activity on Toxocara canis eggs

BackgroundVisceral toxocariasis is a parasitic zoonosis caused by Toxocara canis. The prevalence of this parasite in dogs, soil contamination and the resistance of eggs increase human exposure to the disease. Moreover, the difficulties of the control measures justify the need for alternative ones.AimsThe objective of this study was to evaluate the in vitro ovicidal activity of fungi isolated from soils from public places in the city of Pelotas, Rio Grande do Sul, Brazil, on Toxocara canis.MethodsSamples of soil from ten localities were inoculated onto Petri dishes with 2% water–agar (WA) that contained antibiotics, and incubated at 25 °C/21 days. Isolated fungi were tested in vitro for ovicidal activity, with five replicates. One mL of an embryonated Toxocara canis egg suspension (10³ eggs) was poured over the fungal cultures after 10 days of growth. At intervals of 7, 14 and 21 days, 100 eggs were removed from each plaque and evaluated by optical microscopy.ResultsAcremonium, Aspergillus, Bipolaris, Fusarium, Gliocladium, Mucor and Trichoderma were isolated from the soil. A significant ovicidal type 3 effect was observed in Trichoderma, Fusarium solani complex and Acremonium. Those isolates from the genus Trichoderma showed their ovicidal effect on the 14th day of fungus–egg interaction. The other fungal genera tested showed a type 2 effect.ConclusionsThese results suggest that the use of Trichoderma and Fusarium solani complex in biological control of T. canis is promising; however, further studies should be performed.     

Volatile Substances Produced by Fusarium oxysporum from Coffee Rhizosphere and Other Microbes affect Meloidogyne incognita and Arthrobotrys conoides

Microorganisms produce volatile organic compounds (VOCs) which mediate interactions with other organisms and may be the basis for the development of new methods to control plant-parasitic nematodes that damage coffee plants. In the present work, 35 fungal isolates were isolated from coffee plant rhizosphere, Meloidogyne exigua eggs and egg masses. Most of the fungal isolates belonged to the genus Fusarium and presented in vitro antagonism classified as mutual exclusion and parasitism against the nematode-predator fungus Arthrobotrys conoides (isolated from coffee roots). These results and the stronger activity of VOCs against this fungus by 12 endophytic bacteria may account for the failure of A. conoides to reduce plant-parasitic nematodes in coffee fields. VOCs from 13 fungal isolates caused more than 40% immobility to Meloidogyne incognita second stage juveniles (J₂), and those of three isolates (two Fusarium oxysporum isolates and an F. solani isolate) also led to 88-96% J₂ mortality. M. incognita J₂ infectivity decreased as a function of increased exposure time to F. oxysporum isolate 21 VOCs. Gas chromatography-mass spectrometry (GC-MS) analysis lead to the detection of 38 VOCs produced by F. oxysporum is. 21 culture. Only five were present in amounts above 1% of the total: dioctyl disulfide (it may also be 2-propyldecan-1-ol or 1-(2-hydroxyethoxy) tridecane); caryophyllene; 4-methyl-2,6-di-tert-butylphenol; and acoradiene. One of them was not identified. Volatiles toxic to nematodes make a difference among interacting microorganisms in coffee rhizosphere defining an additional attribute of a biocontrol agent against plant-parasitic nematodes.     

Fungal Diversity in Deep Sea Sediments from East Yap Trench and Their Denitrification Potential

Abstract

In recent years, the hadal trenches have been recognized as biological hot spots for deep sea researchers. Due to high hydrostatic pressure, low temperatures, high salinity and low nutrients, the microorganisms in hadal trenches may have unique community structure with potential for biotechnical application. Compared with bacteria and archaea, the diversity and ecological roles of fungi in hadal trenches remain largely unknown. The purpose of this study was to explore fungal diversity in deep-sea sediments of the Yap trench and their denitrification potential. In the present study, a total of 106 fungal strains were isolated from six sediment samples collected in the East Yap Trench. These fungi belonged to five classes (Dothideomycetes, Eurotiomycetes, Sordariomycetes, Cystobasidiomycetes, and Microbotryomycetes), thirteen genera (Acremonium, Alternaria, Aureobasidium, Aspergillus, Cladosporium, Cystobasidium, Engyodontium, Gliomastix, Lecanicillium, Penicillium, Phoma, Rhodotorula and Trichoderma) and eighteen species, based on morphological identification and ITS-rDNA sequence analysis. Among them, the dominant genus is Cladosporium, which accounting for 42.45% of the total fungal strains. Meanwhile, the denitrification potential of the fungal strains was also examined with two different denitrifying media (nitrate and nitrite as sole substrate, respectively). Two fungal strains (Acremonium sp. and Aspergillus versicolor), were found to be able to produce N₂O ex situ in the presence of nitrite. No fungus was found to produce N₂O by using nitrate. Our results suggest that fungi in hadal sediments, play important roles in nitrogen cycles.     

Azolla filiculoides Nitrogenase Activity Decrease Induced by Inoculation with Chlamydomonas sp.

Experiments were conducted to determine the influence of Chlamydomonas sp. on nitrogen fixation (C₂H₂ → C₂H₄) in Azolla filiculoides and on the nitrogen fixation and growth of free-living Anabaena azollae 2B organisms. Inoculation of azolla medium with Chlamydomonas sp. was associated with decreased nitrogenase activity in A. filiculoides and with increases in the density of a fungal population identified as Acremonium sp. Subsequent inoculation of azolla medium with this fungus was also accompanied by a significant decrease in nitrogenase activity of A. filiculoides. However, the extent of depression of nitrogenase activity was significantly higher when azolla medium was inoculated with Chlamydomonas sp. than when it was inoculated with Acremonium sp. Inoculation of nitrogen-free Stanier medium with either Acremonium sp. or Chlamydomonas sp. did not adversely affect the growth or nitrogenase activity of free-living A. azollae. Decreased nitrogenase activity in A. filiculoides is apparently related to the adverse influence of the green alga and the fungus on the macrosymbiont. The mechanisms that might be involved are discussed.     

The strain HEB01 of Fusarium sp., a new pathogen that infects brown soft scale

The objectives of the present study were to identify a fungal strain, HEB01, isolated from naturally infected brown soft scale, Coccus hesperidum L. (Hemiptera: Coccidae), and to determine whether it is an entomopathogenic fungus. Fungal culture, reinoculation test, morphological observations, and infection behaviors were investigated. Additionally, the fungal gene sequence of translation elongation factor 1-a (EF-1a) was obtained for molecular identification. The results showed that the fungal strain HEB01 belongs to the Fusarium incarnatum-equiseti species complex and is part of the family Nectriaceae (Hypocreales: Sordariomycetes). The inoculation test and observations of infection behaviors indicated that strain HEB01 is a pathogenic fungus and confirmed that it infects brown soft scale. Thus, the HEB01 strain of Fusarium incarnatum-equiseti is the first pathogen in the genus Fusarium to be isolated from a brown soft scale.     

Fungi Associated with Females and Cysts of Heterodera glycines in a Florida Soybean Field

Fungal colonization was determined for females and cysts of Heterodera glycines on soybean roots or in rhizosphere soil from a Florida soybean field. A total of 1,620 females and cysts were examined in 1991, and 1,303 were examined in 1992. More than 35 species of fungi were isolated from females and cysts. The frequency of fungi colonizing white and yellow females was low, but a high frequency of fungi was encountered in brown cysts, which increased with time of exposure of the cysts to the soil. No single fungal species predominated in the nematode females or cysts in this field. Rarely was a female or cyst colonized by more than one fungus. The common fungi isolated from the females and cysts were Neocosmospora vasinfecta, Fusarium solani, Fusarium oxysporum, Dictyochaeta coffeae, Dictyochaeta heteroderae, Pyrenochaeta terrestris, Exophiala pisciphila, Gliocladium catenulatum, Stagonospora heteroderae, and a black yeast-like fungus. The communities of common fungal species isolated from cysts in several regions in the southeastern United States appear to be similar.     

Pyrone derivatives from the marine-derived fungus Nigrospora sp. PSU-F18

Pyrones, named nigrosporapyrones A-D (1-4), and five known compounds were isolated from the marine-derived fungus Nigrospora PSU-F18. Their structures were elucidated on the basis of spectroscopic evidence. The antibacterial activity against the standard Staphylococcus aureus ATCC 25923 and methicillin-resistant S. aureus was evaluated.     

Acremonium as an endophytic bioagent against date palm Fusarium wilt

A total of 250 endophytic fungal isolates, representing 30 morphotaxa, were isolated and characterised, they were collected from the different living symptomless parts of date palm trees of orchards of six Egyptian governorates. Colonisation was greater in samples from the midrib than in those from laminar tissue and slightly greater at the tip of the lamina compared with the base of the leaf. Acremonium spp. were frequently isolated as date palm root endophytes. Acremonium isolates were screened in Petri dishes to select the highest antagonistic one against an Algerian isolate of Fusarium oxysporum f.sp. albedinis. Two-week-old axenically reared date palm seedlings grown in Petri dishes were directly injected with spore suspension (1.5?×?10⁷ spores/ml) of a pure culture of the virulent antagonistic isolate of Acremonium sp. One week after endophytic colonisation, date palm seedlings were then challenged with the pathogen, Fusarium albedinis. The challenged seedlings exhibited a significant reduction in wilt symptom percentage (by 87.0%), while the seedlings exposed to Fusarial toxin without pathogen exhibited the wilt disease symptoms. This indicates that the endophyte ably depresses any toxic action of F. albedinis. The endophytic fungus was recovered from sites distant from the point of inoculation after six?months from the application, indicating that the Acremonium sp. has the potential to move throughout the tissue plant, even the end time of trial. The Acremonium mode of action, as a biocontrol agent, was discussed.