Paeonol produced by Chaetomium sp., an endophytic fungus isolated from Paeonia suffruticosa

In order to research the relationship between endophytic fungus and active ingredients in medicinal Paeonia suffruticosa, a total of 57 fungal isolates were isolated from the roots, stems, leaves and buds of medicinal plant Paeonia ostii; mycelium was collected after these fungal isolates were fermented on PDA medium for a few days; then the mycelium products were extracted; their extracts were analyzed by gas chromatography–mass spectrometry. With this method, a strain endophytic fungi named J1-2 which can produce paeonol was screened. Paeonol produced by J1-2 was analyzed by using a high resolution mass spectrometer (HRMS) and nuclear magnetic resonance (NMR). The potential paeonol-procucing named J1-2 was identified Chaetomium based on morphological characteristics and ITS sequence analysis. The current research initially indicates that endophytic fungi can affect the potency of peony. At the same time it also indicates that the numerous endophytic fungi inside the medicinal Paeonia suffruticosa are precious resource for the pharmaceutical natural products that are originally from the Paeonia suffruticosa.     

Richness and bioactivity of culturable soil fungi from the Fildes Peninsula,Antarctica

Since the discovery of penicillin, fungi have been an important source of bioactive natural products. However, as a specific resource, the bioactive potentiality and specificity of fungal metabolites from the Antarctic region have had little attention. In this paper, we investigated the diversity patterns and biological activities of cultivable fungi isolated from soil samples in Fildes Peninsula, King George Island, Antarctica. Fungal communities showed low abundance and diversity; a total of 150 cultivable fungi were isolated from eight soil samples. After being dereplicated by morphological characteristics and chemical fingerprints, 47 fungal isolates were identified by ITS-rDNA sequencing. We confirmed that these isolates belonged to at least 11 different genera and clustered into nine groups corresponding to taxonomic orders in the phylogenetic analysis. Using two different fermentation conditions, 94 crude extracts acquired from the abovementioned different metabolite characteristic isolates were screened by bioactivity assay and 18 isolates produced biologically active compounds. Compared with HPLC–DAD–UV fingerprint analysis of culture extracts and standard compounds, two bioactive components secalonic acid and chetracins were identified. Our research suggests that the abundance and diversity of Antarctic cultivable fungal communities exhibit unique ecological characteristics and potential producers of novel natural bioactive products.     

Detection and characterization of fungal infections of Ammophila arenaria (marram grass) roots by denaturing gradient gel electrophoresis of specifically amplified 18s rDNA.

Marram grass (Ammophila arenaria L.), a sand-stabilizing plant species in coastal dune areas, is affected by a specific pathosystem thought to include both plant-pathogenic fungi and nematodes. To study the fungal component of this pathosystem, we developed a method for the cultivation-independent detection and characterization of fungi infecting plant roots based on denaturing gradient gel electrophoresis (DGGE) of specifically amplified DNA fragments coding for 18S rRNA (rDNA). A nested PCR strategy was employed to amplify a 569-bp region of the 18S rRNA gene, with the addition of a 36-bp GC clamp, from fungal isolates, from roots of test plants infected in the laboratory, and from field samples of marram grass roots from both healthy and degenerating stands from coastal dunes in The Netherlands. PCR products from fungal isolates were subjected to DGGE to examine the variation seen both between different fungal taxa and within a single species. DGGE of the 18S rDNA fragments could resolve species differences from fungi used in this study yet was unable to discriminate between strains of a single species. The 18S rRNA genes from 20 isolates of fungal species previously recovered from A. arenaria roots were cloned and partially sequenced to aid in the interpretation of DGGE data. DGGE patterns recovered from laboratory plants showed that this technique could reliably identify known plant-infecting fungi. Amplification products from field A. arenaria roots also were analyzed by DGGE, and the major bands were excised, reamplified, sequenced, and subjected to phylogenetic analysis. Some recovered 18S rDNA sequences allowed for phylogenetic placement to the genus level, whereas other sequences were not closely related to known fungal 18S rDNA sequences. The molecular data presented here reveal fungal diversity not detected in previous culture-based surveys.     

Analysis of the dynamics of fungal communities in soil via fungal-specific PCR of soil DNA followed by denaturing gradient gel electrophoresis

A molecular method for profiling of fungal communities in soil was applied in experiments in soil microcosms, with two objectives, (1) to assess the persistence of two selected fungal species in soil, and (2) to analyze the response of the natural fungal community to a spill of sulphurous petrol in the same soil. To achieve the aims, two soil DNA extraction methods, one originally designed for the direct extraction of bacterial community DNA and the other one aimed to obtain fungal DNA, were tested for their efficiency in recovering DNA of fungal origin from soil. Both methods allowed for the efficient extraction of DNA from introduced Trichoderma harzianum spores as well as Arthrobotrys oligospora mycelial fragments, at comparable rates. Several PCR amplification systems based on primers specific for fungal 18S ribosomal RNA genes were tested to design strategies for the assessment of fungal communities in soil. The PCR systems produced amplicons of expected size with DNA of most fungi studied, which included members of the Ascomycetes, Basidiomycetes, Zygomycetes and Chytridiomycetes. On the other hand, the 18S rRNA genes of Oomycetes (including key plant pathogens) were poorly amplified. Plant (Solanum tuberosum), nematode (Meloidogyne sp.) and bacterial DNA was not amplified. For studies of soil fungal communities, a nested PCR approach was selected, in which the first PCR provided the required specificity for fungi, whereas the second (nested) PCR served to produce amplicons separable on denaturing gradient gels. Denaturing gradient gel electrophoresis (DGGE) allowed the resolution of mixtures of PCR products of several different fungi, as well as products resulting from mixed-template amplifications, into distinct banding patterns. The persistence of fungal species in soil was assessed using T. harzianum spores and A. oligospora hyphal fragments added to silt loam soil microcosms. Using PCR-DGGE, these fungi were detectable for about 14 days and 2 months, respectively. Both singly-inoculated soils and soils that had received mixed inoculants revealed, next to bands resulting from indigenous fungi, the expected bands in the DGGE profiles. The A. oligospora specific amplicon, by virtue of its unique migration in the denaturing gradient, was well detectable, whereas the T. harzianum specific product comigrated with products from indigenous fungi. PCR-DGGE analysis of DNA obtained from the silt loam soil treated with dibenzothiophene-containing petrol showed the progressive selection of specific fungal bands over time, whereas this selection was not observed in untreated soil microcosms. Cloning of individual molecules from the selected bands and analysis of their sequences revealed a complex of targets which clustered with the 18S rDNA sequences of the closely-related species Nectria haematococca, N. ochroleuca and Fusarium solani. Fungal isolates obtained from the treated soil on PDA plates were identified as Trichoderma sp., whereas those on Comada agar fell into the Cylindrocarpon group (anamorph of Nectria spp).     

Isolation and characterization of endophytic huperzine A-producing fungi from Huperzia serrata

Huperzia serrata is a producer of huperzine A (HupA), a cholinesterase inhibitor (ChEI). Over 120 endophytic fungi were recovered from this plant and screened for Hup-A and nine were found. These nine represented seven different fungal genera with the most significant producer being Shiraia sp. A total of 127 endophytic fungi isolates obtained from the root, stem, and leaf segments of H. serrata were grouped into 19 genera based on their morphological traits and sequence analysis of the internal transcribed spacers (ITS1-5.8S-ITS2), indicating endophytic fungi in H. serrata are diverse and abundant. Aspergillus, Podospora, Penicillium, Colletotrichum, and Acremonium were the frequent genera, whereas the remaining genera were infrequent groups. Overall, 39 endophytic fungi isolates showed acetylcholinesterase (AChE) inhibition in vitro. Nine endophytic fungi isolates from seven distinct genera were capable of producing HupA verified by thin-layer chromatography and reverse-phase high-performance liquid chromatography (RP-HPLC). Among the HupA-producing fungi, the yield of HupA produced by the Shiraia sp. Slf14 was 327.8 μg/l in potato dextrose broth, and the fungal HupA was further validated by mass spectrometry (ESI-MS). The present study demonstrated that H. serrata was a fascinating fungal reservoir for producing HupA and other ChEIs.     

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.     

The phylogenetic relationship and non‐specific symbiotic habit of mycorrhiza fungi from a terrestrial orchid (Cymbidium)

To investigate the specificity of the symbiotic relationship between Cymbidium plants and their mycorrhiza fungi, thirty mycorrhiza fungi were isolated from roots of six terrestrial Cymbidium species. The internal transcribed spacer (ITS) region of nuclear ribosomal DNA (rDNA) were amplified by polymerase chain reaction (PCR) with universal fungal primers ITS1/ITS4. All fungal strains isolated from natural roots of orchids were inoculated into the rhizomes of in vitro Cymbidium goeringii. Phylogenetic analysis indicated fungal isolates of different cluster could be obtained from a special terrestrial Cymbidium species. Observation of light microscope and scanning electron microscope showed that fungi entered the cortical tissue by destroying cell wall of epidermal cells, where they formed hyphal knots in the cortical cells and were digested gradually. A large number of small protuberances were visible on cross sections of the rhizome. There was no strict inter‐species specificity between the isolated mycorrhiza fungi and terrestrial Cymbidium.     

Fungal endophytes from leaves of Avicennia marina growing in semi-arid environment as a promising source for bioactive compounds

Endophytic fungi are broadly dispersed residing inside plant tissues and have been demonstrated as a treasure for bioactive natural products. Unexplored harsh and heavy metal contaminant habitat of Avicennia marina may have diverse and potential fungal association. Therefore, this work aimed to isolate the culturable fungal endophytes associated with leaves of A. marina and to evaluate their medical potentialities. Seventeen isolates of endophyte fungi were isolated from healthy leaves and their antimicrobial activities were evaluated. Results showed that isolates had activity against micro-organisms in addition to their antioxidant activity produced a variety of phenolic compounds, besides exhibited a lowest cytotoxicity against ATCC-CCL-81 cell line. Consequently, selected endophytic fungal isolates were identified genetically as Chaetomium sp., Chaetomium madrasense, Chaetomium sp., Chaetomium globosum, Aspergillus hiratsukae, Aspergillus ochraceus, Alternaria tenuissima and Curvularia lunata with gene bank accession numbers MT089951, MT089952, MT089953, MT089954, MT089955, MT089956, MT089957 and MT089958 respectively. The most potent fungus extract was analysed using Gas chromatography–mass spectrometry which verified the presence of numerous bioactive compounds. These findings confirmed that new endophytic fungal strains derived from A. marina thrive in harsh ecosystem produce bioactive metabolites which can be recommended as a novel source for drug discovery.     

Diversity and Antimicrobial Activity of Culturable Fungi Isolated from Six Species of the South China Sea Gorgonians

Fungi in gorgonians are now known to cause gorgonian diseases, but little attention has been paid to the nature of fungal communities associated with gorgonians. The diversity of culturable fungi associated with six species of healthy South China Sea gorgonians were investigated using a culture-dependent method followed by analysis of fungal internal transcribed spacer sequences. A total of 121 fungal isolates were recovered and identified using the Basic Local Alignment Search Tool search program. These belonged to 41 fungal species from 20 genera. Of these, 30 species and 12 genera are new reports for gorgonians, and the genera Aspergillus and Penicillium were the most diverse and common in the six gorgonian species. Comparison of the fungal communities in the six gorgonian species, together with results from previous relevant studies, indicated that different gorgonian species and the same gorgonian species living in different geographic locations had different fungal communities. The gorgonian Dichotella gemmacea harbored the most fungal species and isolates, while Echinogorgia aurantiaca had the least fungal diversity. Among the six media used for fungal isolation, potato glucose agar yielded the highest isolates (27 isolates), while glucose peptone starch agar had the best recoverability of fungal species (15 species). The antimicrobial activity of the 121 fungal isolates was tested against three marine bacteria and two marine gorgonian pathogenic fungi. A relatively high proportion (38?%) of fungal isolates displayed distinct antibacterial and antifungal activity, suggesting that the gorgonian-associated fungi may aid their hosts in protection against pathogens. This is the first report comparing the diversity of fungal communities among the South China Sea gorgonians. It contributes to our knowledge of gorgonian-associated fungi and further increases the pool of fungi available for natural bioactive product screening.     

Antagonism between Bacteria and Fungi on Decomposing Aquatic Plant Litter

Bacterial and fungal decomposers of aquatic plant litter may exhibit either synergistic or antagonistic interactions, which are likely to influence microbial growth as well as the decomposition of litter and, eventually, the carbon metabolism of aquatic systems. To elucidate such interactions, we inoculated decomposing Phragmites culms in microcosms with fungal isolates and with natural communities of bacteria and fungi in different combinations. The development of fungal and bacterial biomass and the carbon dynamics were studied during several months of degradation. The results show a bilateral antagonistic relationship between bacteria and fungi. After 3 months, fungal biomass accumulation was approximately 12 times higher in the absence than in the presence of bacteria. Bacterial biomass accumulation was about double in the absence of fungi compared to when fungi were present. Similar interactions developed between a natural assemblage of bacteria and five different fungal strains isolated from Phragmites litter (three identified hyphomycetes and two unidentified strains). Despite the great difference in biomass development between the treatments, the carbon metabolism was similar regardless of whether fungi and/or bacteria were present alone or in coexistence. We suggest that the antagonism between bacteria and fungi is an important controlling factor for microbial colonization and growth on aquatic plant litter.     

Desert soil fungi isolated from Saudi Arabia: cultivable fungal community and biochemical production

Desert soils harbor fungi that have survived under highly stressed conditions of high temperature and little available moisture. This study was designed to survey the communities of cultivable fungi in the desert soils of the Arabian Peninsula and to screen the fungi for the potentially valuable antioxidants (flavonoids, phenols, saponins, steroids, tannins, terpenoids, and alkaloids) and enzymes (cellulase, laccase, lipase, protease, amylase, and chitinase). Desert soil was sampled at 30 localities representing different areas of Saudi Arabia and studied for physico-chemical soil properties. Five types of soil texture (sand, loamy sand, sandy loam, silty loam, and sandy clay loam) were observed. A total of 25 saprotrophic species was identified molecularly from 68 isolates. Our survey revealed 13 culturable fungal species that have not been reported previously from Arabian desert soils and six more species not reported from Saudi Arabian desert soils. The most commonly recorded genera were Aspergillus (isolated from 20 localities) and Penicillium (6 localities). The measurements of biochemicals revealed that antioxidants were produced by 49 and enzymes by 52 isolates; only six isolates did not produce any biochemicals. The highest biochemical activity was observed for the isolates Fusarium brachygibbosum and A. phoenicis. Other active isolates were A. proliferans and P. chrysogenum. The same species, for instance, A. niger had isolates of both high and low biochemical activities. Principal component analysis gave a tentative indication of a relationship between the biochemical activity of fungi isolated from soil and soil texture variables namely the content of silt, clay and sand. However, any generalizable relation between soil properties and fungal biochemical activities cannot be suggested. Each fungal isolate is probable to produce several antioxidants and enzymes, as shown by the correlation within the compound groups. Desert soil warrants further research as a promising source of biochemicals.     

The relationship between a leaf-rolling moth (Dactylioglypha tonica) and fungi covering the cocoon.

To discover the relationship between a leaf-rolling moth and the fungi densely covering its cocoons, the rolled nest leaves were collected in two districts in Japan and antibacterial properties of the fungi were examined. Cocoons and fungi isolated from the nest were classified into 5 categories by the growth stages of the insects, and 7 categories based on taxonomic properties and pigment productivity, respectively. The dominant genus was Penicillium in each location. However, the composition of the fungal categories was different and seemed to depend on their circumstances. From all cocoons with larvae, the strains that belonged to the same fungal category and produced the same antibiotic (deoxyherqueinone) were isolated. From these results, the species-specific relationship between the insect and fungi or fungal products was considered to be not extremely tight, and it was suggested the period of the larval spinning of the cocoon is a key stage of this unique relationship.     

Comparison of Glutathione S-transferase Activity and Concentration in Aflatoxin-Producing and their Non-Toxigenic Counterpart Isolates

In this study, two techniques were used to compare the specific activity and total concentration of mycelial glutathione S-transferase (GST) in fungal strains isolated from natural sources. The fungi identified as Aspergillus parasiticus and Aspergillus flavus have been divided into two groups based on their ability to produce aflatoxins. Altogether 26 fungi were isolated, among which 12 were capable of producing varying levels of aflatoxin and 14 were proved to be non-toxigenic. GST specific activity in mycelial preparation was measured spectrophotometrically using 2,1-chloro-2,4-dinitrobenzene as the substrate. The results showed that the mean GST activity in toxigenic isolates was 25.06 +/- 9.8 mumol/mg protein/min which was 2.8-fold greater than that measured in non-toxigenic isolates (8.84 +/- 5.5 mumol/mg protein/min). Moreover, the GST concentration was compared in toxigenic and non-toxigenic isolates using an Enzyme Linked Immunosorbent Assay based on antigen (fungal preparation) and antibody (antibody produced against fungal GST in rabbit). The results of ELISA showed that the mean GST level in toxigenic and non-toxigenic fungi was 1.17 +/- 0.55 and 0.40 +/- 0.24, respectively. These results further confirm that the aflatoxin production in the fungal strains is correlated with GST expression and using ELISA, it is possible to discriminate aflatoxin-producing fungi from their non-toxigenic counterparts.     

Fungi and actinomycetes associated with Meloidogyne spp. eggs and females in China and their biocontrol potential

A survey was conducted to determine the microflora on eggs and females of Meloidogyne spp. collected from plant roots and infested soil in China. A total of 455 fungal isolates belonging to 24 genera and 52 isolates of actinomycetes were obtained from 28 samples from greenhouses and fields in Hainan, Yunnan, Fujian, Hebei, Shandong, and Beijing. The predominant fungal species were Paecilomyces lilacinus (49.3% of the isolates), Fusarium spp. (7.9%), Pochonia chlamydosporia (6.9%), Penicillium spp. (5.7%), Aspergillus spp. (3.2%), and Acremonium spp. (2.8%). Actinomycetes were frequently encountered (10.3%) as well. A total of 350 isolates of nematophagous fungi and actinomycetes were evaluated for their parasitism of eggs and effects on egg hatch and juvenile mortality in vitro. Pathogenicity varied among isolates, and 29.1% of isolates parasitized over 90% eggs 4 days after inoculation. Results also show that seven isolates of fungi and actinomycetes reduced egg hatch rates to less than 10% contrasted to the control of 65.8%, and three isolates killed all hatched juveniles after 7 days. Seventeen fungal isolates and four actinomycete isolates with high pathogenicity in vitro were selected to test biocontrol efficacy in the greenhouse. They reduced tomato root gall index by 13.4-58.9% compared to the no treatment control.     

Susceptibility of phosphogypsum to fungal growth and the effect of various biocides

Natural gypsum (NG) and phosphogypsum (PG) were tested for resistance to fungal growth based on standard test ASTM D 3273-86, with the recommended mixture of three fungal species, and using the same test modified by the use of a Cladosporium sp. A, isolated from a gypsum plaster ceiling. In the standard test little growth occurred on any of the test specimens. However, abundant fungal growth was produced by the Cladosporium sp. A on phosphogypsum, which was much more susceptible than natural gypsum. Phosphogypsum heated to 600°C to destroy organic residues was resistant to growth of Cladosporium sp. A, as well as other fungi isolated from phosphogypsum panels stored in the environment for 2 years: Cladosporium sp. B, Aspergillus niger and Trichoderma sp. Phosphogypsum moulded in Petri dishes was susceptible to growth of a wide range of fungi, although Fusarium sp. and Rhizopus sp. caused practically no discoloration of the substrate. Six biocides were separately incorporated into the phosphogypsum at concentrations recommended by the suppliers and test specimens incubated on Sabouraud agar inoculated with various fungal isolates. The biocide 2-N-octyl-4-isothiazolin-3-one was the most efficient compound. It prevented the growth of the fungi most likely to cause health problems in buildings, but not that of Helminthosporium sp., isolated from powdered phosphogypsum in the factory. This was the most resistant fungus showing growth on all biocide-containing specimens.     

厦门杏林湾红树林根际真菌分离及活性分析

【背景】海洋微生物是天然药物资源宝库,海洋环境中的微生物能够产生很多区别于陆生微生物的天然产物。红树林生长于陆地与海洋交界带的滩涂浅滩,是陆地向海洋过渡的特殊生态系统,可能蕴含着丰富的微生物资源和潜在的大量结构新颖的代谢产物。【目的】以厦门杏林湾红树林根际海泥和海水为研究对象,探索其中可培养海洋真菌的多样性及其发酵提取物的抗细菌和抗真菌活性,以期为发现新的药物先导化合物提供菌株资源。【方法】样品预处理后涂布于GPY、PDA、Martin和MEA这4种培养基,28℃倒置培养,待培养基上长出合适大小的菌落后,挑取单菌落接种于PDA培养基纯化。利用纸片扩散法对发酵提取物进行抗菌活性筛选,通过高效液相色谱分析提取物的化学多样性,并采用形态观察结合rDNAITS序列分析对活性较好的4株真菌进行菌种鉴定。【结果】共分离出71株真菌,其中49株真菌对金黄色葡萄球菌有抗性,6株真菌对白色念珠菌有抗性,2株真菌对大肠杆菌有抗性,菌株HS5-MEA-4和HS6-MEA-10初步鉴定为土曲霉,菌株HS5-GPY-7和HS6-GPY-15分别为棘孢曲霉和Aspergillus templicola。【结论】初步认知了厦门杏林湾红树林环境真菌多样性及其发酵提取物的活性和化学多样性特征,为后续海洋真菌次级代谢产物研究提供了依据。     

不同培养基对兰科药用植物手参原球茎共生真菌的分离效果

兰科植物手参Gymnadenia conopsea作为国家二级重点保护野生植物具有重要的药用价值。目前手参还未实现人工栽培,但其种子的真菌共生萌发已获成功。为明确除促萌发真菌外,还有哪些土著真菌参与了手参种子的萌发过程,本研究在自然条件下采用促萌发真菌伴播手参种子,获得了种子萌发形成的原球茎,进而对比了6种常见的培养基PDA (马铃薯葡萄糖琼脂培养基)、MMN (改良Melin-Norkrans培养基)、FIM (真菌分离培养基)、MEA (麦芽浸膏琼脂培养基)、CAM (胡萝卜葡萄糖琼脂培养基)和CMA (玉米粉琼脂培养基)对手参原球茎共生真菌分离效果的影响。共从6种培养基上分离获得了75个菌株,其中MMN、CAM、PDA、FIM、MEA、CMA培养基依次分离得到20株、16株、15株、11株、8株、5株菌。此外,真菌的多样性分析结果表明,MMN培养基的Chao 1、Shannon-Wiener和Simpson多样性指数最高,CAM和PDA培养基次之,CMA培养基最低。综上所述,真菌分离效果最好的是MMN培养基,其次是CAM和PDA培养基,而FIM和MEA培养基对真菌的分离效果影响不大,CMA培养基的分离效果最差。本研究结果可为其他兰科植物原球茎共生真菌的分离提供借鉴,所获得的菌株也有望进一步应用于功能菌剂的研发。     

锁阳及其寄主白刺内生真菌的生态分布及遗传关系

首次研究了寄生植物锁阳及其寄主白刺内生真菌的分布特征及遗传关系.采用组织块法分离天然白刺、寄生体中锁阳和白刺的内生真菌,利用ITS-rDNA分子序列并结合形态学方法鉴定菌种,研究内生真菌的分离率、定殖率、分离频率、多样性指数、均匀度指数及相似性系数等的差异,以及寄生关系中内生真菌的多样性、遗传关系及分布特征等.结果表明: 本次获得的49株内生真菌隶属于18个分类单元,95.9%为子囊菌,4.1%为担子菌;内生真菌总分离率为15.3%,总定殖率为25.0%;天然白刺中内生真菌Shannon多样性指数最大,为2.13;锁阳花序与锁阳茎的内生真菌相似性系数最大,为0.50;镰孢菌属为白刺的优势菌属,青霉属为锁阳的优势菌属.锁阳与白刺寄生体中真菌类群的差异性分布表明寄生关系对内生真菌群落存在一定影响.     

从南方山荷叶分离出一株产鬼臼毒素类似物的内生真菌

从南方山荷叶 (Diphylleiasinensis)的根、根状茎及叶柄部位共分离出 5 4株内生真菌。通过薄层层析(TLC)对 5 4株内生真菌的液体发酵培养物进行了初步分析 ,再采用高效液相色谱 (HPLC)做进一步检测 ,得到 1株产鬼臼毒素类似物的内生真菌 (SJ2 1 ) ,经鉴定为纠错青霉 (Penicilliumimplicatum)。     

In vivo passage through calves of nematophagous fungi selected for biocontrol of parasitic nematodes.

The experiment was designed to test the survival and performance of stress selected nematophagous fungi after passage through the gastro-intestinal tract of cattle. Ruminating calves were fed daily with a fixed amount of fungal material grown on barley grains. The excreted dung was collected on days four and five after the start of the feeding experiment. Barley grains were washed out of the excreted dung and incoculated on water-agar plates. After incubation for one week, nine of ten fungal isolates were re-isolated from these plates. The predatory capacity of the fungi in the excreted faeces was tested in a dung pat bioassay and a faecal culture system. In the dung pat bioassay, two fungi of the genus Arthrobotrys and six of the genus Duddingtonia reduced the development of Ostertagia ostertagi third stage larvae by 85% (61%-93%), compared to the number of larvae developed from fungus-free control pats. In seven out of these eight isolates, the reduction of larvae in the faecal cultures was 92% (76%-99%).