Fungal diversity associated with nine species of marine macroalgae, including three brown algae, four green algae and two red algae from Qingdao coast of China were investigated using cultured-dependent method. A total of 92 fungal strains were isolated from 34 asymptomatic algal thalli. On the basis of morphological characteristics and internal transcribed spacer (ITS) rDNA sequences analysis, they were identified and assigned to 56 species of Ascomycota, one species of Basidiomycota and one species of Zygomycota. The dominant genera were Acremonium, Aspergillus, Cladosporium, Penicillium and Scopulariopsis. Anamorphic fungi were represented by 40 species, accounting for 75% of the total isolates. The highest fungal diversity was uncovered from the green alga Codium fragile, followed by the brown alga Sargassum thunbergii, and the lowest was observed from the red alga Corallina officinalis. This is the first report of the fungal diversity associated with marine algae from Chinese coastal regions, and will contribute to further insight into the understanding of the functions of algicolous fungi.
The ectomycorrhizal (ECM) fungal community in the rhizospheric soil of Betula platyphylla in Inner Mongolia was investigated. Heilihe Natural Reserve, Saihanwula Natural Reserve and Helanshan Natural Reserve of Inner Mongolia were selected as sample plots. DNA ITS1 region of the fungi in rhizospheric soil were sequenced using the Illumina MiSeq High-throughput sequencing platform. A total of 1 041 sequences of ectomycorrhizal fungi obtained, dividing into 404 OTUs which belong to two phyla, six classes, eleven orders, 25 families and 38 genera, being mainly distributed in Basidiomycota. The dominant ECM fungal OTUs totalled 21, belonging to Russula, Lactarius, Clavulina, Cortinarius, Sebacina, Inocybe, Amphinema and Hygrophorus, and Russula has the highest frequency. In Heilihe and Saihanwula, Russula and Clavulina are predominant, while Cortinarius and Sebacina are predominant in Helanshan. The degree of influence of soil environmental factors on ECM fungal descends in the order of pH>Na>Ca>Mg>TN>K>TP>TC. The pH, Ca and Mg had significant effects on the distribution of dominant ECM fungi in these sample sites. Ectomycorrhizal fungal community of Betula platyphylla in Heilihe and Saihanwula is more similar than that in Helanshan at the genus level and dominant genus level.
A strain of nematode-trapping fungus WZ27, which could spontaneously produce conidial trap without any exogenous induction, was isolated from the burned field in Cangshan mountain, Dali, Yunnan Province. Based on morphological and molecular identification the strain was referred to Dactylellina parvicolla. The percentage of the spontaneously producing conidial trap was 18.3%, and the number of conidial trap can be significantly increased by induction of nematode and cow dung. Compared with the reference strain, the trapping device formation time of our strain was shorter (P<0.001), and the nematode trapping efficiency was higher (P=0.003).
Artificial rearing of Hepialus sp. larvae is necessary prerequisite for cultivation of Chinese cordyceps. However, Isaria farinosa is a common contaminant during Hepialus larva rearing and has significantly impact on the cultivation of Chinese cordyceps. The symptoms, infection and histopathology of Hepialus larvae parasitised by I. farinosa were observed in this study. After four days of inoculation, some black spots appeared around the abdominal trachea and the trachea was somewhat black. Subsequently, the larvae were shown as paralysis, death, body color change, rigid contraction, mycelial coating and finally forming many coremia. After penetration of the cuticle, the hypha firstly multiplied in the hemolymph, and then gradually degraded the host tissues and organs such as fatbody, muscle, digestive tract, silk-glands and Malpighian tubules. The larval coelom was occupied by massive hyphae and the larvae eventually become mummified. Histological sections showed that I. farinosa could infect Hepialus sp. larvae via spiracle and hyphae broke into short hyphal segments in the haemolymph. Mycelia directly penetrating the cuticle of larvae and digestive tract were not observed. This study provided essential information to prevent contamination and disease caused by I. farinosa during the artificial rearing of Hepialus sp. larvae.
Helitron is a family of transposable element in eukaryotes. Unlike other transposons, Helitron can encode a replication initiator protein (Rep) and a helicase (Hel), and expand in the genome by rolling circle replication. This study systematically analyzed the autonomous Helitron elements in nine Fusarium oxysporum strains. The generation of evolutionary trees indicated that there were two types of Helitron, i.e., FoHeli1 and FoHeli2. The sequences are highly similar and boundary is clear between the members of FoHeli1. There is a conserved motif “TATTTT” at the 3′-end, a hairpin of the 3′-end upstream and 12bp inverted repeats making upstream of hairpin and 5′-end pairing with each other. Based on above analytic results, the FoHeli1 element was cloned from the F. oxysporum strain Fo4287, and the transposable ability of FoHeli element was verified through construction of the dual translocation system and PEG mediated protoplast transformation of F. graminearum PH-1 strain.
The geographical distribution of Lentinula edodes was surveyed from the information of literatures published and nucleic acid databases. The genetic diversity was evaluated based on ITS sequences. The results confirmed that L. edodes was distributed in over 21 provinces or regions in China and L. edodes in Sichuan, Yunnan and Hubei were most frequently studied. There is a strong correlation between the geographic origins of the isolates. The genetic diversity centers were located in southwestern and northwestern China. The investigation may help us to explore germplasm of the fungus.
A putative transcription factor VvHox1, encoding a homeobox containing protein that may be involved in fruiting body differentiation, was found in the Chinese mushroom, Volvariella volvacea. We inferred that transcription factor VvHox1 may regulate the fruiting body differentiation based on the gene expression in different developmental stages. Analysis of gene structure by mapping transcriptome reads showed that VvHox1 spanned 2 856bp and comprised four exons and three introns. Based on quantitative real-time PCR and digital gene expression, we found that the expression value of VvHox1 exhibited a continuous increase during three developmental stages (heterokaryon, primordia and egg stage), with the highest expression value at the egg (forming of egg-like fruiting body) stage, however, it decreased sharply in the elongation stage. Consequently, we infer that this transcription factor VvHox1 may control the morphogenesis of V. volvacea in fruiting body formation.
A cultivated Pleurotus ostreatus strain was used to investigate the effects of adding the alkaline lignin or cooperating with simple carbon source or nitrogen source on laccase activities in submerged fermentation. The results demonstrated that the laccase activities secreted by the P. ostreatus from different induction media were significantly different (P<0.001), and the biomass obtained by the P. ostreatus from different induction media were also significantly different (P<0.001). Only using the alkaline lignin or cooperating with simple carbon source glucose was in favour of laccase production of P. ostreatus, increasing laccase activities and advancing enzyme production time. Only using alkaline lignin as inducer is unfavourable to accumulating mycelial biomass. The induction media rich in simple carbon source or nitrogen source, whether containing alkaline lignin, are favourable to accumulating mycelial biomass. The mycelial biomass and laccase activities obtained from the media rich in simple carbon source or nitrogen source with additional alkaline lignin were higher than those obtained from the media only containing simple carbon source or nitrogen source without additional alkaline lignin. In general, the laccase activity in the media containing alkaline lignin was constantly higher than that in simple carbon or nitrogen media without additional alkaline lignin. The inductive effect of the media containing alkaline lignin on laccase production of P. ostreatus was stronger as compared with simple carbon or nitrogen media without additional alkaline lignin.
The powdered fruit bodies of Coprinus comatus were firstly extracted by ethanol and the ethanol extract was then reextracted sequentially by ethyl acetate and petroleum ether. The anti-diabetic activity of each extract was evaluated by α-glucosidase inhibition assay. The results showed that ethyl acetate extract (EAE) had better anti-diabetic activity than others. Ten compounds from EAE were isolated by column chromatography and identified by spectroscopic methods including NMR and MS. These compounds were (1) cis, cis-9,12-octadecadienoic acid, (2) cis-9-octadecenoic acid, (3) (22E,24R)-ergosterol-5,7,22- triene-3β-alcohol, (4) 3β-5α-6α-22E-ergosterol-7,22-diene-3,5,6-triol-6-linoleate, (5) 3β-5α-6α-22E-ergosterol-7,22-diene-3,5,6- triol-6-oleate, (6) diisobutyl phthalate, (7) p-hydroxy benzene ethanol, (8) 4-hydroxy phenethyl acetate, (9) 3-(4-hydroxy-3-) fatty acid, and (10) N-trans-3,4-methylenedioxy cinnamic acyl-3-methoxy tyramine. N-trans-3,4-methylenedioxy cinnamic acyl-3-methoxy tyramine had better anti-diabetic activity with IC50 value of 4.17mg/mL.
The decolorization ability of sodium alginate immobilized Irpex lacteus was optimized under different levels of pH, dye concentration, metal ions, carbon source, nitrogen source, and salt concentration. The results showed that the optimized conditions of immobilized I. lacteus were: application of 3% alginate and 5% calcium chloride, immobilization period of 6h, and inoculation amount of 10g/100mL. All six dyes tested could be decolorized by immobilized I. lacteus, but decolorization of alizarin red dye was particularly obvious. Decolorization rate decreased with the increase of dye concentration, and significantly declined when dye concentration >250mg/L. The optimum pH was 7, and the suitable carbon and nitrogen sources were soluble starch and ammonium nitrate respectively. Decolorization rate of alizarin red tended to decline with the increase of salt concentration, and significantly declined when salt concentration >3%. The decolorization rate could be maintained at a relatively high level of 94.20% after being kept in physiological saline for 10 days, and it was still maintained at 88.70% after immobilized I. lacteus was recycled for 5 times.
The purpose of the current study was to explore the correlation between different processing way and the content of diisobutyl phthalate (DiBP) in Auricularia heimuer. The results were evaluated by HPLC after A. heimuer fruiting bodies were immersed in pure water, baking soda water and boiling water. The determination was performed on a Agilent Eclipse XDB-C18 (4.6mm×150mm, 5μm) column. The mobile phase consisted of methanol and 0.1% formic acid water solution, and gradient elution was carried out under a flow rate of 0.25mL/min at 25°C. The wavelength for measurement was 254nm. The results showed that DiBP content could be increased dramatically after immersion in pure water for 1d, 2d, 3d and 4d. The DiBP content in soaked fruiting bodies is averagely 2.707 times the content in dried ones. Immersion in baking soda water or scalding with boiling water, the content of DiBP decreased to 0.066 times the content of DiBP in dried fruit bodies. Our result provides scientific grounds for cookery of this edible fungus.
A universal method for determination of monosaccharide components of Cordyceps polysaccharide was established by using PMP pre-column derivatization HPLC method. Using nine kinds of monosaccharide standards as the object, the derivative reactive conditions including temperature, duration, pH and PMP derivatization were optimized through single factor and response surface test. The optimized method was then used for determining the monosaccharide composition of polysaccharides in Cordyceps militaris from three different regions. The optimal derivatization conditions were summed up as follows: the molar ratio of PMP to monosaccharide was 12:1; the optimal temperature was 80°C; the reactive duration was 60min, and the optimal derivatization pH was 8.3. The methodology validation has proved that this method is stable, reliable and repeatable. Mannose, galacturonic acid, glucose, galactose and arabinose were detected stably in three batches of Cordyceps militaris polysaccharides, and their molar ratio was 3.8:1.6:5.4:5.8:1. The result provides technical support for monosaccharide composition analysis and evaluation of structure-activity relationship of Cordyceps polysaccharide．
