Microbiotic crusts widely distribute in arid and semi-arid desert areas, which are of great significance for maintaining the stability of desert ecosystem. Lichen crust, as important component and one of the main types of microbiotic crusts, has unique superiority in sand, carbon and nitrogen fixation. This paper summarizes the domestic and foreign research progress of desert lichen distribution, community composition and influence factors on regional and local scales, and discussed the function of possible biotic factors affecting desert lichen symbiosis on microscale. Although the existing studies have indicated that the climate type, precipitation, physical and chemical properties of soil, microtopography and temperature can impact lichen habit, species, abundance and coverage, and the biotic factors connected with lichen thallus, lichen crust and lichen crust soil are related to the function of maintaining life activities and distribution of lichens, the conclusions are still limited due to mainly lack of specialized researches on desert lichens on regional scale, and experimental exploration and validation on the lichen-associated biological functions. To a certain extent, all the mentioned limitations will restrict the study of large-scale application of artificial lichen crusts in deserts. The application of desert lichen crust is prospected in order to provide references for artificial construction of desert lichen crusts, arid and semi-arid desert control, and ecological restoration.
Lichen, a symbiotic organism of fungi and algae, has special physiological structure and unique living environment. It can survive in harsh environments such as deserts, high mountains, and frozen soils. Lichens and their endolichenic fungi product many secondary metabolites that exhibit divers bioactivities with potential application values. This review focuses on the recent research progresses of the bioactive secondary metabolites from lichens and their endolichenic fungi.
Based on morphology, anatomy, chemistry and molecular biology, a new species of lichenized fungus Astrothelium, A. sinense, and a new record to China A. macrocarpum were reported. The new species is characterized by thallus bullate-folded, perithecia surrounded by whitish rim except for dark ostiolar area, and thallus and pseudostromata with lichexanthone both showing UV+ yellow. Comparisons and discussions with their similar species were provided. These are basic data for compilation of Flora Lichenum Sinicorum.
The endolichenic fungus Daldinia childiae isolated from Punctelia sp. was cultivated by rice solid medium and the fermentative product was extracted with ethyl acetate. The secondary metabolites purified by the method of silica gel column chromatography and recrystallization were identified by combining nuclear magnetic resonance spectroscopy with mass spectrometry. The free radical scavenging ability of the compounds was determined by DPPH method. Eight compounds were isolated from Daldinia childiae, and they were determined as 4-hydroxy- benzeneethanol(1), 4-methoxy-5-car-bomethoxy-6-pentyl-2H-pyran-2-one(2), 1-(2,6-dihydroxyphenyl) butan-1-one(3), 8-methoxy-1-naphthol(4), 1,8-dimethoxynaphthalene(5), methyl 2-undecenoate- 3-undecanoate-cyclohexyl-1,4-dienyl ester(6), uracil(7) and acetic acid (8). The compounds 1, 6 and 8 were isolated from the genus of Daldinia for the first time. The compound 4 under concentration of 3mg/mL showed siginificant activity of free radical scavenging. The compound 3 and 5 exhibited slight free radical scavenging ability.
The extraction process and in vitro activities of polysaccharides from Umbilicaria muehlenbergii were investigated. The optimization of the extraction parameters was investigated by single-factor and response surface methodology. In vitro activities of the polysaccharides were evaluated by the methods of scavenging DPPH, hydroxyl radical, superoxide anion and nitrite. Results showed that the optimal parameters were obtained under the conditions of 5 extraction cycles each sustaining for 4.5h at a liquid-solid ratio of 40:1 at 90°C. The polysaccharide yield extracted was 10.63%. The polysaccharides exhibited significant antioxidant and antitumor activities in vitro, and hopefully could be developed as a product with potential medicinal value.
Six species of the lichen genus Parmeliella are reported from China. Among them, P. appalachensis, P. himalayana, P. pannosa and P. thriptophylla are new to China. Descriptions, comments and a key to the known species from China with illustrations for the new records are presented.
Eleven species of the lichen genus Pannaria are reported from China. Among them, P. andina, P. elatior, P. prolificans, P. ramulosa, P. subfusca and P. tavaresii are new to China. Descriptions, comments, a key to the known species from China, and illustrations for the new records are given.
Four new records of Porina (Porinaceae) are reported from China, viz. P. fluminea, P. fulvella, P. tetramera and P. thaxteri. Detailed descriptions and morphological figures were provided for each species. The specimens were collected from Shandong, Guizhou, Guangdong and Hainan provinces. All specimens examined were deposited in Herbarium Mycologicum Academiae Sinicae (HMAS) and Plant Herbarium of Shandong Normal University (SDNU).
An endolichenic fungus strain Daldinia childiae DPS-165-9 was isolated from lichen Punctelia sp. collected from the Cloak Mountain Scenic Area in Duyun, Guizhou. The liquid-fermented product was extracted by ethyl acetate. Inhibitory activity of the extract against pathogenic and drug-resistant bacterial strains were performed by punch method. The results showed that D. childiae DPS-165-9 could inhibit Staphylococcus aureus 25923 and 6538, drug-resistant Staphylococcus epidermidis Z12, drug-resistant Brucella sp. B103, drug-resistant Bacillus subtilis 163 and drug-resistant Micrococcus luteus 261. The fungus is probably developable as a new antimicrobial agent.
The systematic position and scientific name of “chanhua”, an important cordycipitoid mushroom has long been chaotic. Because its teleomorph was unknown, it has long been regarded as Isaria (Paecilomyces) cicadae named based on a Brazilian specimen. The teleomorph of this taxon was recently discovered from Mt. Jinggangshan, Eastern China. In the present paper, the teleomorph and anamorph of the species were studied morphologically and multigene-phylogenetically, the hypothesis that I. cicadae was a species complex was demonstrated, and “chanhua” was verified as a new species in the genus Cordyceps of Cordicipitaceae and then Cordyceps chanhua was proposed using the ancient Chinese name “chanhua” as its epithet. Stromata of C. chanhua are light orange to light saffron, ovoid, 476-602×222-319μm; ascospores are filiform, 246-360×1.5-1.8μm and part spores are 6.4-13.8×2.1-3.1μm. Conidia are long ellipsoid or cylindrical, 3.5-10.5×1.5-4.5μm.
Edible mycorrhizal fungi (EMF) are ubiquitous in forests and of high ecological and economic values. Pinus massoniana is one of the main timber tree species widely planted in southern China, and the forests are rich in EMF resources. A 4-year field survey was conducted to clarify the diversity of EMF in P. massoniana forests in central Guizhou. The phenology of EMF fructification as well as the characteristics of ectomycorrhiza (ECM) and symbiotic association between EMF and P. massoniana root system were also investigated. 20 EMF species were found in P. massoniana forest, belonging to 1 class, 4 orders, 10 families, and 13 genera. At the family level, Russulaceae is the most abundant. ECM morphology is mostly in dichotomous and coralloid forms. Mycorrhizal exploration types include contact exploration type, short distance exploration type, medium distance exploration type, and long distance exploration type, of which the contact exploration type, short distance exploration type and long distance exploration type are dominant. The occurrence of EMF sporocarps is significantly affected by temperature and precipitation (P<0.01). Overall, June to October is the period of high incidence of EMF sporocarps in P. massoniana forest. Suillus bovinus, S. leteus, Lactarius vividus, Lactifluus volemus and Russula rosea would be the good candidates for further commercial utilization.
There are two variations of one-year-old Pinus massoniana seedlings, one with primary needles and another with secondary needles. However, it is still poorly understood that whether there are variations in root morphology and ectomycorrhiza (ECM) fungal community between these seedlings. In this study, the seedlings’ roots of the two variants were collected to analyze root morphology by WANSHEN LA-S system and measure root activity by TTC method, and DNA ITS regions of the fungi in roots were sequenced with IonS5 TMXL platform. The results showed that there were significant differences in the root system of the seedlings. The total root length, surface area, volume, number of branching, and root activity of the seedlings with secondary needles were 16% to 44% higher than those of the seedlings with primary needles. The DNA sequences of ECM fungi were classified into 44 OTUs belonging to 2 phyla, 5 classes, 9 orders, 13 families, and 15 genera. Sphaerosporella was dominant genera, reaching 95.59% of total genera in the seedlings with primary needles, and 60.43% in the seedlings with secondary needles. Rhizopogon also occupied a higher proportion (16.43%) of ECM fungi in the seedlings with secondary needles. Shannon diversity index, Chao 1, and Ace abundance index of ECM fungi of the seedlings with secondary needles were significantly higher than those of the seedlings with primary needles.
Sequencing and bioinformatic analysis of the mitochondrial gene sequence of “jinhua-jun (golden flower fungus)”, a dominant microbe in fermented dark tea were conducted. Phylogenetic relationship of “jinhua-jun” with related microbes was analysed. The results showed that the mitochondrial genome of “jinhua-jun” was a circular DNA molecule with total length of 77 649bp, in which A, T, C and G bases were 34.14%, 37.64%, 15.61% and 12.61%, respectively, with significant A-T bias. A total of 42 genes coded 15 PCGs, 2 rRNAs and 25 tRNAs. In comparison with its closely related species, “jinhua-jun” missed out a trnT-TGT copy but gained one trnM-CAT copy in the mitochondria, showing that the genetic sequence was highly conservative. The amino acids with relatively high coding frequency were Leu, Ile, Ser, Phe and Val. The four codons with the highest RSCU frequency were UUA, AUA, UUU and AAU. All of the 25 tRNA genes could form a typical cloverleaf structure with 35 G-U mismatches. Phylogenetic analysis indicated that Aspergillus pseudoglaucus was close to “jinhua-jun” in taxonomic position. Our results suggested that “jinhua-jun” should be included in Aspergillus and referred to A. cristatus.
Fat is the main nutrient in the early stage of germination and infection of Puccinia striiformis f. sp. tritici (Pst) urediniospores. The enzymatic hydrolysate of fat is transformed into sugar through glyoxylate cycle for growth and development of the pathogen. Lipase is the key enzyme of fat metabolism. Based on the published genome sequence, the lipase gene PsLIP1 (1 302bp) from Pst was cloned using RT-PCR, and 433 amino acids were encoded. PsLIP1 was successfully transformed into Pichia pastoris cells (GS115) and expressed with high activity. Enzyme activity analysis showed that the optimum pH was 8.0 and the optimum temperature was 60°C. Zn 2+, Cu2+ and Ca2+ promoted the lipase activity of PsLIP1, while Fe2+ and Mn2+ inhibited the activity. The results provide a foundation for further analysis of the mechanism of lipase action and formulation of control strategies of wheat stripe rust based on perspective of energy metabolism.
This work aims to analyze alternative splicing (AS) and alternative polyadenylation (APA) of Nosema ceranae genes on the basis of our previously obtained third-generation nanopore full-length transcriptome data. Astalavista software was used to identify the type of AS events of N. ceranae genes. TAPIS pipeline was utilized to explore APA sites of N. ceranae genes. MEME software was employed to investigate statistics of sequences at 50bp upstream of poly (A) splicing sites followed by motif identification. In this study, five AS events occurred in five genes were identified, including one alternative donor site (ADS) and four intron retention (IR). In addition, a total of 233 genes with APA were discovered, among them those containing one poly (A) splicing site were the most abundant (143, 61.37%). Upstream and downstream sequences of 3’ UTR within N. ceranae full-length transcripts showed an obvious base bias, and U was enriched in the upstream of 3’ UTR, while A was enriched in the downstream of 3’ UTR. Three motifs such as AAUAAA, UGAUGC and GCGACG were identified at the upstream of poly (A) splicing site. Taken together, the results reveal the complexity of the transcriptome of N. ceranae, improve the annotation of current genome and transcriptome, and provide a foundation for further investigation of the molecule role of various isoforms. Our work provides a valuable idea and method reference for study on AS and APA in other fungi.
Aspergillus flavus is an opportunistic pathogenic filamentous fungus that can influence plant and animals. The conservative Cla4 PAK (p21-activated protein kinases) protein kinase is important for signal transmission, cell cycle progression and morphogenesis. A homologous recombination method was used to construct a knockout mutant strain (ΔAflcla4) for revealing the biological functions of Aflcla4 gene performing vegetative growth, spore production, sclerotial formation, aflatoxin production, stress response and pathogenicity of A. flavus. Compared with the wild type strain, mycelium growth rate of the knockout mutant ΔAflcla4 was significantly decreased, the mycelium was irregularly bifurcated, conidial production was significantly reduced, and the color became transparent. The ΔAflcla4 mutant displayed increase in sensitivity to cell wall integrity and osmotic stresses. It was found that the pathogenicity of ΔAflcla4 to peanut and corn seeds became impaired, and the ability to produce toxins was also dramatically declined. The deletion of Aflcla4 resulted in the defect of sclerotial formation, causing decrease of ability to deal with adverse environmental changes. PAK kinase Cla4 plays critical roles in development, aflatoxin production, and sclerotial formation by regulating related genes expression in A. flavus.
The extraction conditions of polysaccharides from Inonotus obliquus (IO) fruiting body were optimized by response surface methodology (RSM). The hypoglycemic activities of the IO polysaccharides were evaluated and bioactive polysaccharide fraction (BPF) was confirmed through enzyme and cell modes in vitro. The hypoglycemic mechanism and monosaccharide composition of BPF were preliminarily analyzed. The yield of polysaccharides was (2.79±0.03)% under the optimal conditions. Fractions of IOP30, IOP60 and IOP80 were obtained from crude polysaccharide extracts by differential alcohol precipitation. Among them, IOP30 showed the strongest α-glucosidase inhibitory activity (IC50=38.20μg/mL) and acted as a noncompetitive inhibitor in enzyme kinetics. The glucose consumption rate of HepG2 cells was obviously different from that of the experimental control group (P<0.01), after treating with IOP30 of 0.01, 0.10 and 1.00mg/mL. When insulin (10 -7mmol/L) and IOP30 (0.10, 1.00mg/mL) were added together, the glucose consumption rate of HepG2 cells was increased more obviously (P<0.01). IOP30 was mainly composed of rhamnose (7.93%), arabinose (3.12%), xylose (11.15%), mannose (19.08%), glucose (39.17%) and galactose (19.15%). In conclusion, IOP30 isolated from the fruiting body of IO possessed significant hypoglycemic activity by reducing the formation of postprandial blood glucose via α-glucosidase inhibitory activity, promoting the glucose metabolism in the surrounding tissues of cells, and enhancing the sensitivity of liver cells to insulin.
The components and involved metabolic pathways of Cordyceps militaris were analyzed by quantitative and metabonomics methods and their effects on hyperuricemia caused by purine metabolic disorders were studied. The results show that C. militaris contains 233 metabolites, including cordycepin and cordyceps acid already reported and corticosteroids, epinephrine and glutathione, etc. belonging to ten different categories such as carboxylic acids and their derivatives, organic oxides and fatty acyl groups. KEGG analysis showed their significant enrichment in 19 metabolic pathways including ABC transport protein, amino acid biosynthesis and purine metabolism. Compared with the experimental model group, the serum uric acid level and xanthine oxidase activities were significantly decreased in the middle and high dose treatment groups of mice administrated with C. militaris (P<0.05), showing obvious effects on the prevention and treatment of hyperuricemia. The functional mechanism of C. militaris metabolites was analyzed and discussed.
To investigate the antioxidant and hypoglycemic activities of polyphenolic alkaloid-enriched extract (PAE) from Sarcodon leucopus fruiting bodies in Tibet, the DPPH free radical scavenging activities, intracellular antioxidant capacity (CAA) and inhibitory effects on key enzymes linked to diabetes (maltase, sucrase, and α-amylase activity from rat small intestine) were tested. The results showed that PAE had antioxidant activity in a dose-dependent manner, and the IC50 value of DPPH free radicals was (18.12±1.09)μg/mL, and CAA50 value of the intracellular antioxidant capacity was (13.60±0.13)μg/mL. PAE also showed selective Inhibitory effect on key enzymes relevant to diabetes with a dose-dependent effect. IC50 values of maltase and sucrase were (60.86±4.50)μg/mL and (64.60±4.53)μg/mL, respectively, while the inhibitory effect on α-amylase was extremely low. PAE of S. leucopus was found to possess antioxidant and hypoglycemic activities, which was hopeful of developing safe and active ingredient of functional foods or medicines for preventing or alleviating diabetes.
A new meroterpenoid, asptercin A (1), together with six known analogues (1R,4aR,6aR,12aR,12bS)-1,3,4,4a,5,6,6a,12,12a,12b-decahydro-1,4a,12a-trihydroxy-4,4,6a,12b-tetramethyl-9-(4’-methoxyphenyl)-2H,11H-naphtho[2,1-b]pyrano[3,4-e]pyran-11-one (2), arisugacin D (3), arisugacin H (4), territrems A-C (5-7) were obtained from the fermented extract of Aspergillus terreus xy03 isolated from Xylocarpus moluccensis in southern Thailand by means of silica gel, ODS, Sephadex LH-20 column chromatography and preparative HPLC. At the concentration of 0.1mmol/L, compounds 2, 4, 5, 6 and 7 exhibited strong AChE inhibitory activities with the inhibition rates of 76.1%, 77.1%, 86.1%, 86.1% and 86.0%, respectively.
Secondary metabolites of an endophytic fungus Fusarium sporotrichioides SC1608 inhabiting an aquatic plant Eichhornia crassipes were investigated. Four glycosphingolipids, asperamide B (1), asperamide D and E (2, 3), cerebrosides A (4), and two cyclicdepsipeptides, acuminatum A (5) and acuminatum B (6) were obtained. The structures of these compounds were determined by HRESI-MS, NMR and LC-MS/MS, of which compound 2 and 3 are two new sphingolipids. Compounds 5 and 6 showed strong antifungal activities against Penicillium digitatum and Bipolaris maydis in vitro. The results preliminarily revealed the antifungal compounds of F. sporotrichioides SC1608 fermentation products and enriched the knowledge of chemical diversity of secondary metabolites of this fungus.
Phanerochaete chrysosporium was used to study the decolorization effects of anthraquinone dyes by white rot fungi under various parameters of RBBR (initial concentration, pH, temperature and metal ions). UV-Vis absorption spectrum analysis, FTIR analysis, GC-MS analysis and phytotoxicity test were used to analyze the possible degradation pathways of RBBR and the toxicity of the degradation products. The results showed that the decolorization rate can reach more than 95% in 24h at pH 4.2, 28°C and 5mmol/L Mn2+ when RBBR concentration was 200mg/L. The biodegradation pathway of RBBR was initiated by the cleavage of the nitrogen bond connecting the benzene ring and the anthraquinone of RBBR, then generated 1-aminoanthraquinone and M-(β-hydroxyethyl barium sulfate sodium sulfate) aniline. The amino group on the 1-aminoanthraquinone was substituted by a hydroxyl group, and then oxidized, de-ringed, and rearranged into phthalic acid. The phthalic acid was oxidized to form a small molecule organic acid succinic acid, at the same time, the amino group on the M-(β-hydroxyethyl barium sulfate sodium sulfate) aniline was oxidized to form succinic acid and other small molecular acids, carbon dioxide and water. Phytotoxicity experiment showed that the toxicity of RBBR could be reduced by P. chrysosporium. In conclusion, P. chrysosporium could effectively decolorize high-concentration RBBR, and reduce the toxicity of dyes to plants.
Ganoderma species show various medicinal effects, and polysaccharides are one of the main active components. At present, the colorimetric method is commonly used for the quantification of Ganoderma polysaccharides, but it has the shortcomings of complicated operation and lack of safety of environment. Recently, we applied near-infrared (NIR) spectroscopy for quantitative analysis of Ganoderma polysaccharides, but direct analysis of polysaccharides in fruiting bodies was found to be inaccurate. In this work, a better quantification model of using near-infrared spectroscopy to detect and analyze the polysaccharides in the water extracts of Ganoderma fruiting body was established. The selected ranges for the model is 5 461.7-4 235.1cm-1, with the pretreatment of taking the first derivative and vector normalization of the NIR spectra, and the rank=7, R2=0.9007, RMSECV=2.54, RPD=3.17, RMSEP=3.45, RPD=2.42, Corr. Coeff.=0.9181. This new method is proved to be practicable for rapid quantitative analysis of the active ingredients of Ganoderma fruiting body.
