A new species, Pseudocercospora stereospermi sp. nov. on Stereospermum tetragonum from China is reported. Description, figure and compared with similar species are provided. Type specimen is deposited in HMAS.
According to the current International Code of Nomenclature and genera in Bionectriaceae, Hypocreaceae, and Nectriaceae (Hypocreales) proposed for acceptance or rejection, eight species previously assigned to Bionectria, Cosmospora, Gibberella and Haematonectria are transferred to Clonostachys, Pseudocosmospora, Fusarium and Neocosmospora as new combinations.
Based on the analyses of the 18S rDNA, 28S rDNA and MCM7 gene sequences, phylogenetic relationships among some genera of the family Helotiaceae were investigated. The results showed that the species within the same genus were clustered together forming a well-defined clade. However, the family seems not monophyletic since some genera investigated are associated with members of other families of the order Helotiales.
Spiraea pubescens is an important soil retaining shrub which widely grows in arid environment of Daqingshan Mountains, Inner Mongolia. Rhizosphere soil and roots of S. pubescens at different altitudes (1 515m, 1 410m and 1 305m above sea level) in Shuimocun were collected to analyze colonization rate, spore density, diversity and community composition of arbuscular mycorrhizal fungi (AMF). The results showed that spore density and colonization rate were significantly higher at alt. 1 515m than those at alt. 1 410m and 1 305m, while arbuscular abundance had no significant difference in different altitudes. A total of 71 AMF OTUs (operational taxonomic units) were detected in all soil samples by Illumina MiSeq sequencing. Glomus was the dominant genus, and AMF community composition was significantly different in different altitudes. Margalef index, Chao 1 index and Shannon-Wiener index increased with the increase of altitude, which were significantly higher at alt. 1 515m than at alt. 1 410m and 1 305m. No significant difference was observed in Simpson index in different altitudes. Soil organic matter and plant cover were significantly negatively correlated with spore density. Available phosphorus, water content and plant cover were significantly negatively correlated with colonization rate. Shannon-Wiener, Simpson index, Margalef index and Chao 1 index were significantly positively correlated with elevation, but significantly negatively correlated with available phosphorus and plant cover. The results would provide important scientific basis to further discuss the effects of AMF on the survival of S. pubescens in arid areas.
In order to evaluate the quantity of protoplasts and the degradation situation of the cell wall from the hyphae of nematode-trapping fungus Duddingtonia flagrans more accurately and quickly, the protoplasts of Duddingtonia flagrans produced by enzymolysis were labeled by a reactive fluorescent dye carboxyfluorescein diacetate succinimidyl ester (CFSE). The optimal dosage and timing as well as the temperature of protoplast release and labeling were determined. Protoplast regeneration after labeling was also observed. The results indicate that the ideal conditions for protoplast labeling are as follows: the final dosage of CFSE is 10μmol/L, and labeling duration is 15min at the temperature of 36°C. In addition, the experiment showed that CFSE would not affect the regeneration rate of protoplast from Duddingtonia flagrans. The method provides an ideal technique for rapid evaluation of the protoplast-producing efficiency from the nematode-trapping fungus.
Conidiation is a biological process important for filamentous fungi to reproduce, disperse and ultimately form infection. In order to elucidate the regulatory mechanisms of conidiation, transcriptomic profiles generated by RNA-seq from the samples of the model fungus Neurospora crassa wild-type strain before and after induction of conidiation were compared. Gene ontology analysis of differentially expressed genes indicated that oxidation-reduction process and metabolic process are mainly influenced during the induction of conidiation. Among these, genes related to reactive oxygen species (ROS) are enriched, indicating the ROS production during conidiation. Moreover, genes associated with conidiation (including regulatory genes and spore structural genes) expressed specifically. To understand the roles of these induced genes in conidiation, we analyzed the phenotype of the mutants for 424 up-regulated genes and found six genes [NCU09792, NCU05159, NCU06112, NCU05079, NCU00461, NCU07521 (fwd-2)] that positively contribute to conidiation. The conidial productions of these gene deletion mutants are much lower than that of the wild type strain, and the increased expression of these genes in conidiations indicates that they are involved in positive regulation of conidiation. Our work facilitates the understanding of conidiation and its regulatory networks in N. crassa.
Hexokinases are generally believed to play pleiotropic roles in biological processes such as sugar sensing and phosphorylation. A hexokinase-like protein encoding gene Achka was identified in the cephalosporin producing strain Acremonium chrysogenum. RT-PCR analysis revealed that Achka contained four introns. The deduced protein of Achka contains 484 amino acids with a calculated molecular mass of 53.7kDa. Achka was expressed in E. coli and the recombinant AcHKA was purified. Kinetic characterization showed that AcHKA had higher affinity, but lower phosphorylation efficiency for glucose compared to fructose. Disruption of Achka significantly delayed the fungal growth in MMCB media when fructose, sucrose or mannose was used as the sole carbon source. These results suggest that AcHKA is a hexokinase and plays the key roles in the utilization of fructose, sucrose and mannose in Acremonium chrysogenum.
The broth of Cordyceps cicadae fermented in oscillating manner was extracted with ethyl acetate, and antifungal activity of the extract was tested by Oxford cup method. Active substances from the ethyl acetate extract were purified by high performance liquid chromatography. The chemical structure of the active compound was identified by physio-chemical properties and spectral data. Our experiment showed that the ethyl acetate extract presented a significant inhibiting effect against Canidia albicans, suggesting that Canidia albicans was the best indicator for studying antifungal activity of ethyl acetate extract from fermentation broth of Cordyceps cicadae. The antifungal active substance of the extract was identified as myriocin.
The effect of different chemical substances on the permeability of cell membrane of Tremella fuciformis spore was investigated in detail by analyzing the effect of different chemical substances on the cell biomass of T. fuciformis transformant, and conductivity and extracellular laccase production of fermentation broth. The results showed that the conductivity could be improved when T. fuciformis spore was treated with 1% dimethyl sulfoxide (DMSO), 0.3% tritonX-100, 0.2% potassium chloride and 0.1% amphotericin B, respectively, and the activity of extracellular laccase produced by T. fuciformis spore can reach 7.00U/L, 6.67U/L, 5.00U/L and 5.00U/L, respectively. As compared with the control, the difference was statistically significant. However, the high foaming surfactant (sodium dodecyl sulfate, SDS) and organic solvents (toluene, glutaraldehyde) were unfavorable for the cell growth and laccase secretion of T. fuciformis spore. These results show that the addition of chemical substances can enhance the extracellular excretion of target products and the current work forms the basis for further study on the high efficient expression of exogenous gene using T. fuciformis spore as bioreactor.
Two cultivated Pleurotus ostreatus strains were used to investigate the effects of adding three different lignocellulose substrates, i.e. sawdust, corncob, and cottonseed hull, on laccase activities in submerged fermentation. The results demonstrated that the laccase activities of the two P. ostreatus strains were significantly different (P<0.001), with the exception of the 3rd and 9th days (P<0.05). Various lignocellulose substrates remarkably affected the laccase activities of different P. ostreatus strains (P<0.001). The laccase-producing capabilities of various strains were different, and they were also inconsistent under different medium conditions. The laccase activity in synthetic medium containing cottonseed hull was higher than that in synthetic medium containing sawdust or corncob, indicating that the cottonseed hull could be considered as a better inducer for enhancing the laccase activities of different P. ostreatus strains.
Amauroderma rugosum is a wild medicinal mushroom commonly sold in China and Malaysia which has antioxidant and anti-tumor activities. The fruiting body development characteristics and nutritional composition of A. rugosum are still unknown. This paper deals with cultivation, analysis of the nutrition and antioxidant activities of wild A. rugosum BYWZ collected from the Baiyun Mountain, Guangzhou City of Guangdong Province. The result showed that by using liquid spawn, the mycelium grew quickly in corn-cob and sawdust mixture substrate. The primordium formed in 40d after inoculation, and the fruiting body matured in 71d. The biological efficiency was 10.84%. Nutritional analysis of the fruiting body showed that A. rugosum BYWZ had crude polysaccharide 3.22g/100g, total triterpenes 1.00%, and crude proteins 14.90g/100g. BYWZ has higher activity in hydroxyl radical scavenging as compared with Ganoderma lingzhi and Ganoderma sinense.
Different concentration of six kinds of heavy metal ions was mixed into culture medium in order to study the tolerance of Morchella importuna towards heavy metal ions. Measuring and calculating the average growth rate and growth promoting rate of mycelia, the growth curve was drawn to obtain the ultimate tolerance concentration of mycelium growth. The ultimate tolerance concentration for sclerotium formation was obtained by giving the appraisal of mycelium density and size and number of sclerotia using qualitative method. The results showed that Morchella importuna had a good tolerance capacity towards Cr6+, Mn2+, Pb2+, Mo6+ and Cu2+ with different concentration. By contraries, the appropriate concentration of the ions could promote the mycelium growth. The optimal concentration for mycelium growth was Cr6+ 100.0mg/L, Mn2+ 100.0mg/L, Cd2+ 5.0mg/L, Pb2+ 50.0mg/L, Mo6+ 20.0mg/L and Cu2+ 100.0mg/L. The optimal concentration for sclerotium formation was Cr6+ 50.0mg/L, Mn2+ 100.0mg/L, Cd2+ 5.0mg/L, Pb2+ 20.0mg/L, Mo6+ 10.0mg/L and Cu2+ 100.0mg/L. Cd2+ concentration inhibiting the growth of mycelium was between 20.0-50.0mg/L.
The toxicology and security of fruiting body of Inonotus sanghuang was evaluated by investigating acute toxicity test and genetic toxicity test (Ames test, micronucleus test of bone marrow cell, sperm shape abnormality test) in mice. The results showed that the maximum tolerance dosage of fruiting body powder of Inonotus sanghuang for mice was more than 12.5g/kg. Under the conditions with or without S9, fruiting body powder of Inonotus sanghuang demonstrated no potential mutagenicity on Salmonella typhimurium TA97a, TA98, TA100 and TA102. Micronucleus test of bone marrow cell and sperm shape abnormality test in mice exhibited negative reaction and there were no significant differences between different doses of treated groups and negative control, indicating that fruiting body powder of Inonotus sanghuang is non-toxic. This study provides a scientific basis for product development and application of fruiting body powder of Inonotus sanghuang.
Vulvovaginal candidiasis (VVC) is a common disease in women, of which Candida albicans is the main pathogen. High dose estrogen was injected into rats subcutaneously to establish the pseudo-oestrus model, then C. albicans SC5314 was inoculated into rats vagina to construct VVC model. The contents of interleukin-2 (IL2), mannose-binding lectin (MBL), and Toll-like receptor-4 (TLR4) in the serum and vaginal lavage fluid of the inoculated rats were tested at different time points. It was found that only TLR4 significantly increased in the serum in the second week, while in the vaginal lavage fluid, IL2 significantly decreased in the third week; TLR4 significantly increased in the second and third weeks, and MBL significantly decreased in first to third weeks. We concluded that the vaginal local immune dysfunction may be closely related to the VVC and RVVC in the pathogenesis of vulvovaginal candidiasis.
