Invasive fungal infections (IFIs) refer to the bloodstream infection or multifocal organ infection mainly caused by pathogenic Candida spp. or Aspergillus spp. Nowadays, the morbidity and mortality of IFIs keep increasing globally, remaining a serious threat to human health. Early and rapid diagnosis is a potent solution for timely treatment and to decrease the mortality rate, which is now the hotspots and difficulty in treating fungal diseases. This review summarized the tools in use and in development for early diagnosis of IFIs, and also predicted the research trends in this field.
Ten cercosporoid species have been described on hosts of the Celastraceae, including seven species belonging to Pseudocercospora. During a survey of cercosporoid fungi in China, three taxa of Pseudocercospora were collected on Euonymus japonicus, and two of them proved to be new to science, namely P. euonymi-japonici and P. beijingensis. Detailed descriptions, illustrations and comparisons with similar species are provided for the two new species and a note on Pseudocercospora cf. destructiva previously reported in China is given. Partial nucleotide sequences of four loci (ITS, tef1-α, act and rbp2) of these taxa were generated for a phylogenetic analysis.
A Pyrenochaetopsis strain isolated from soil of Guizhou Province was identified as Pyrenochaetopsis terricola sp. nov. according to morphological characters in combination with phylogenetic analysis based on sequences of internal transcribed spacer (ITS), nuclear large subunit ribosomal DNA (LSU rDNA), RNA polymerase II second largest subunit (rpb2) and β-tubulin (tub2). A key to the 13 known species of this genus is provided. The holotype and ex-type cultures are deposited in the Herbarium of Department of Plant Pathology, Guizhou University (HGUP) and China General Microbiological Culture Collection Center (CGMCC).
A pot experiment was conducted to investigate the effect of Trichoderma and indigenous arbuscular mycorrhizal (AM) fungi on cucumber seedling growth, using three strains of Trichoderma longibrachiatum, MF-1, MF-2 and MF-3, as inocula. Uninoculation treatment was set up as experimental control. The results showed that significant increases of AM fungal colonization in root and hyphal density in rhizosphere soil were found in the treatments inoculated with MF-1 and MF-2. In comparison with the control, the AM fungal colonization rate in treatments inoculated with MF-1 and MF-2 increased by 26.85% and 54.66% respectively, and the rhizosphere hyphal density of treated seedlings was 3.94 and 3.76 times respectively as high as the untreated control. The shoot dry mass of cucumber seedlings inoculated with MF-2 showed a 39.07% increase as compared with the control. The soil pH and available P of seedlings inoculated with MF-3 were higher than those of untreated seedlings. Pearson correlation analysis indicated that AM fungal colonization rate of seedlings was positively related to the hyphal density and spore density in rhizosphere soil, and soil pH was positively related to the shoot dry mass and soil available P. These results suggest that the AM fungal growth is significantly affected by the inoculation of MF-1 and MF-2, and MF-2 has a greater impact on the plant growth than MF-1, while MF-3 tends to improve soil pH and available P. Compound inocula of Trichoderma are helpful for promoting growth and soil environment of cucumber seedlings.
The best cultivated formula of Trametes suaveolens was screened, and biological characteristics of different growth stages of the fruiting bodies were studied. Eight kinds of sawdust mixing ratios were selected using poplar and willow wood, and straw as material. Eight formulas were screened. Control group (A) and tested group (B) were set up for each formula. Each development stage of fruiting bodies was observed microscopically. The results indicated that Trametes suaveolens can successfully produce fruiting body on the media of willow and poplar wood sawdust. It took 28 days to form plumelet and 32 days to form matured fruiting bodies under the temperature of 13-18°C, humidity of 90%-95% and illumination of astigmatism. The ingredient for highest fruiting was willow sawdust 97%, sucrose 1%, lime 1% and gypsum 1%, and maintenance of moisture content of 65%. During development of fruiting body, the white honeycomb-like primordium was first differentiated. Primordium depended on the pore structure to absorb nutrients, and then the upper layer of primedium cuticle differentiated to black plumelet, and the hymenium formed from the base of honeycomb structure. The internal generative hyphae of plumelet were constantly growing and finally young fruiting body formed with color changed from deep to light. The hyphae differentiated into basidia and basidiospores, and finally fruiting body formed.
Symbiosis of Armillaria spp. and Gastrodia elata is regulated by temperature. Temperature adaption characteristics of the main Armillaria biological species were investigated using eight species of the genus dominated in China as materials. Activities of extracellular enzyme, including laccase, cellulase, and pectinase were determined by diammonium 2,2’-azino-bis (3-ethylbenzothiazoline-6-sulfonate) (ABTS) and 3,5-dinitrosalicylic acid (DNS) methods. The results suggested that there was significant difference in the activity of extracellular enzyme among species, and the activity of these three enzymes increased first and then decreased with the passage of time. Cellulase and pectinase secretion was earlier than laccase during liquid fermentation. Our results also indicated that temperature affected the extracellular laccase and pectase activity of Armillaria spp. significantly, but had no effect on the enzyme production period. Besides, temperature has a great influence on cellulase activity and the time reaching its peak value. The response of extracellular enzyme activity to temperature was also impacted by regional distribution of Armillaria spp. in China. Qinling Mountains and Huaihe River are probably a north-south demarcation line of different response of extracellular enzyme activities of Armillaria species to temperature in China. This study has a guiding significance for biological research of Armillaria spp. and field cultivation of Gastrodia elata.
To determine the population genetic structure of Ustilago maydis, 41 isolates collected from Huang-Huai-Hai region in 2017 were analyzed by using 17 polymorphic ISSR primers. The unweighted pair group method with arithmetic mean (UPGMA) and the Bayesian analysis were used to analyse the population genetic structure of the collected isolates. It was indicated that the isolates could be divided into two geographical groups, and the groups showed clear relationship with the geographical origin of the isolates. Based on demarcation of geographical latitude, the isolates were clustered into 3 groups, 33°-34° N group, 35°-36° N group and 37°-38° N group. The genetic diversity of the 33°-34° N group was the highest. Nei’s gene diversity (H) and Shannon index (I) was 0.2216 and 0.3300, respectively. An estimation of the genetic diversity using analysis of molecular variance (AMOVA) revealed that the highest variance mainly formed in intrapopulation (86%), and subordinately interpopulation (14%) (φpt=0.141).
ITS sequence analysis was used to determine wild Cordyceps cicadae collected from six locations in China, including Tianzhu Mountain in Hangzhou, Zhejiang Province, Huoshan County in Liu’an, Anhui Province, Mopan Mountain in Jurong City, Jiangsu Province, Linhai City in Zhejiang Province, Pingqiao Mountain in Liyang City, Jiangsu Province, and Zhongcun Village in Sanming City, Fujian Province. All these wild samples were identified to be C. cicadae. Amino acid analysis of these wild C. cicadae indicated that amino acid content was the highest in the samples from Tianzhu Mountain, followed by the sample from Linhai city, Pingqiao Mountain, Mopan Mountain, Huoshan County and Zhongcun Village. Nucleoside analysis showed that N6-(2-hydroxyethyl)-adenosine content was the lowest in the samples from Pingqiao Mountain. Both xanthine and cytosine content were the lowest in the samples from Tianzhu Mountain.
A strain NRRL 2155 of the thermophilus fungus Thermomyces dupontii served as recipient, and a combination of homologous recombination and fungal protoplast transformation was applied to generate the targeted gene replacement mutant with a hygromycin resistance gene. The optimum condition for targeted gene replacement was as follows: 2g of fungal mycelia was treated with 15mg/mL lysing enzyme at 28°C for 5.5h to yield protoplasts. After being washed twice with STC buffer, the protoplasts were treated with 10μg of linear replacement DNA fragment through PEG-mediated genetic transformation method. The putative transformants were screened out with hygromycin B marker and further confirmed with PCR analysis. The efficiency rate of this homologous recombination method was up to 20%. This was for the first time that PEG‐mediated protoplast transformation method was applied to T. dupontii, and a stable and efficient gene replacement system was successfully established.
A histone methyltransferases (HMT) gene CgClr4 and two histone deacetylase (HDAC) gene, CgClr3 and CgSir2, were knocked out and then complemented in the endophytic fungus Colletotrichum gloeosporioides strain Cg01 in Huperzia serrata by the PEG-mediated genetic transformation system. The expression of the corresponding genes in the complemented strains were detected by RT-qPCR and huperzine A (HupA) production in the mutant strains were analyzed by high performance liquid chromatography (HPLC). It was found that the HupA production of the 3 gene knockout mutant strains ΔCgClr4, ΔCgClr3 and ΔCgSir2 were 255μg/L, 270μg/L and 244μg/L respectively, decreased by 21.3%, 16.6% and 24.7% as compared with wild type (WT). There is no significant difference between the gene expression of the corresponding gene in the complemented strains ΔCgClr4/CgClr4, ΔCgClr3/CgClr3 and ΔCgSir2/CgSir2 and that in the wild type strain, with the HupA production to be 351.9μg/L, 334.7μg/L and 331μg/L, respectively. The HupA production of complemented strains was restored to that of the wild type strain. The results showed that these three genes had the function of regulating the biosynthesis of HupA, which provided a theoretical basis and a new insight for studying the synthetic mechanism of HupA in endophytic fungi of Huperzia serrata.
A comparison of antioxidant activity in vitro between different extract of Cordyceps militaris MF27 was made, and an extract with high antioxidant activity was obtained. The repair function of the extract to liver injury induced by CCl4 in mice was further studied. Using extracorporeal scavenging rate of DPPH free radical and hydroxyl free radical as antioxidant evaluation index, the extract with high antioxidant activity was selected from fermentation broth, aqueous extract and alcohol extract of mycelia, and aqueous extract and alcohol extract of fruiting body. An acute liver injury model in mice by using CCl4 was established, and evaluation of internal antioxidant and liver protection effect of the extract with high antioxidant activity was made by testing the change of serum biochemical indices and liver function index. The result showed that all the extracts had good antioxidant activity in vitro, but the aqueous extract of fruiting body was possessed of the best ability of scavenging free radicals. The half effective concentration (EC50) of the aqueous extract of fruiting body is 0.096mg/mL for DPPH free radicals and 0.196mg/mL for hydroxyl free radical. At concentration of 1mg/mL, the clearance rate is 94.94% to DPPH free radicals and 70.17% to hydroxyl free radical. In comparison with the model experimental group, the levels of ALT and AST in serum and MDA in liver of the mice in the administration group treated with aqueous extract of fruiting body significantly decreased (P<0.01) as a result of in vivo antioxidation and improvement of liver function. The level of SOD in liver significantly increased (P<0.01), indicating that aqueous extract of the fruiting body can improve oxidative liver damage effectively. Compared with positive control group treated with biphenyl diester, the administration group manifested a great drug efficacy (P>0.05) in the liver index. It is proved that the aqueous extract of fruiting body of C. militaris MF27 has a certain repairing ability in vivo to oxidative liver injury, and possesses potential becoming of antioxidant damage functional product.
Aspergillus fumigatus GZWMJZ-152 can hydrolyze camelliaside A (1) and camelliaside B (2) into kaempferol 3-O-rutinoside (3) under the condition of shaking fermentation using Camellia seed cake medium. Five compounds, kaempferol (4), (-)chaetominine (5), trypacidin (6), 1,2-seco-trypacidin (7) and (-)-syringaresinol (8), were isolated under the condition of solid static fermentation on the same medium. The inhibitory effects of eight compounds on α-glycosidase and DPPH free radical scavenging activity were tested. Compounds 1-3, 5-8 exhibited α-glycosidase inhibitory activity with IC50 values ranging from 133.9 to 308.6μg/mL. Compounds 1, 4, 8 exhibited radical scavenging activity against DPPH with IC50 values ranging from 0.43 to 5.06μg/mL.
Cerrena unicolor is a white rot fungus that can degrade lignin. In this study, the ability of C. unicolor to decolorize and detoxify four solid dyes was assessed. The decolorization conditions of the dyestuffs were optimized and the toxicity of the dyes was measured before and after decolorization. The results proved that C. unicolor could decolorize the four dyes, and the decolorization effect on Congo red was the most obvious. The optimized conditions for Congo red decolorization were: medium containing 20g/L maltose, 1g/L ammonium nitrate and 1mmol/L magnesium sulfate, inoculated with nine pieces of fungal cake of 1cm diameter size in 10mg/L Congo red solution adjusted at pH 7. The toxicity of Congo red before decolorization was greater than that after decolorization. It was evident that the toxicity of Congo red was reduced after degradation by C. unicolor. This study provides a reference for the application of C. unicolor in the decolorization and detoxification of dye wastewater.
