The scientific and technological researches of edible mushroom industry have made remarkable achievements in China since 1978. In recent years, basic research and applied basic research have been carried out rapidly in various fields, and provide strong technical support for the development of edible mushroom industry. In this special issue, 1 literature reviews and 26 research papers are published. Although these papers probably cannot represent the highest level of researches in this field, on the whole they reflect the recent trends in edible mushroom science in China. In these papers, omics analysis, nutrition and bioactive substances and important trait inheritance of Lentinula edodes, Pleurotus spp., Flammulina filiformis, Morchella spp., Volvaria volvacea etc. are focused. Generally speaking, the basic research and applied basic research of edible mushroom in China are relatively backward, and fixed attention to these aspects are urgently needed and financial supports mainly by the National Natural Science Foundation of China are indispensable for the improvement of research condition and level of edible mushroom in China.
The milk cap mushrooms are widely distributed and include a large number of edible ectomycorrhizal species, amongst which Lactarius sect. Deliciosi are probably the most famous due to its high nutritional value and ecological value. The milk cap mushrooms are attributed to Lactarius in the traditional classification, however, they are currently attributed to three genera, Lactarius, Lactifluus and Multifurca, as a result of molecular phylogenetic studies. The mycelium grow slowly and the sporocarps cannot be cultivated saprophytically, and therefore they are difficult to study in a deepgoing way and difficultly domesticated. At present, most studies at home and abroad are still focused on the aspects of classification, phylogeny, isolation and mycelium cultivation, mycorrhizal inoculation, cultivation management techniques in plantations, as well as the nutrition of the mushrooms. L. deliciosus mycorrhizal and wild imitative cultivation have been successful in New Zealand, and commercial cultivation is getting under way. In this article, the research advances and current situations of milk cap mushrooms are summarized, and the research trends at home and abroad are prospected.
Based on the recent molecular analyses on Auricularia, Flammulina and Pleurotus, the International Code of Nomenclature for Algae, Fungi and Plants, and the Nomenclatural Code for Chinese Scientific Names of Fungi and Lichens adopted by the Mycological Society of China in 1986, the nomenclature of the following five important Chinese edible fungi is suggested: Maomuer: Auricularia cornea Ehrenb.; Yumuer: Auricularia cornea Ehrenb.; Enokitake: Flammulina filiformis (Z.W. Ge et al.) P.M. Wang, Y.C. Dai, E. Horak & Zhu L. Yang; Aweigu: Pleurotus eryngii var. ferulae (Lanzi) Sacc.; Bailinggu: Pleurotus tuoliensis (C.J. Mou) M.R. Zhao & Jin X. Zhang.
Next-generation sequencing (NGS) and third-generation sequencing (TGS) technology were used to sequence Flammulina filiformis monokaryon strain 6-3, and de novo assembly using four assembly strategies was performed, and then the quality of assembly was evaluated. As regards parameter of assembly, the quality of NGS assembly is the worst. The total length of contig longer than 10kb is only 24.6Mb; contig N50 is only 23kb, and only 59.27% of data is assembled into contigs. The quality of TGS assembly rectified with NGS is the best. The total length of the contigs longer than 10kb is 38.3Mb; contig N50 is 2.8Mb, and up to 92.16% of data is assembled into contigs. Regarding quality of conserved single-copy gene assembly, the assembled sequences obtained from all four strategies were aligned with conserved single-copy gene of basidiomycetes in the BUSCO database. It is showed that gene completeness for each strategy is over 94%. Verification by PCR and Sanger sequencing indicated that TGS assembly rectified with NGS yielded complete and continuous genome sequence with the least of SNP and InDel. TGS assembly rectified with NGS manifests high N50, high genome assembly ratio, and high base accuracy, and it is a relatively ideal scheme for edible fungal genome sequencing.
RNA-Seq analysis of Pleurotus eryngii at different developmental stages (mycelial stage, primordial stage, and fruiting body stage) was performed using high-throughput sequencing technology. The functions of differentially expressed genes (DEGs) in developmental stages of Pleurotus eryngii were analyzed at the level of transcription. The KEGG enrichment showed that DEGs were mainly enriched in carbon metabolism and amino acid metabolism at the mycelial phase, and in TCA cycle the expression levels of genes encoding citrate synthase, aconitate hydratase, isocitrate dehydrogenase, succinyl-CoA synthetase, succinate dehydrogenase and malate dehydrogenase were increased, indicating that carbon metabolism and amino acid metabolism are the main energy sources during the mycelial stage. The up-regulated DEGs in primordial phase are mainly enriched in fatty acid metabolism. The results of RT-PCR showed that the expression levels of genes which encoded fatty acid synthase and long-chain acyl-CoA synthetase were down-regulated and the expression levels of genes which encoded superoxide dismutase and catalase were up-regulated. It is suggested that fatty acid metabolism and antioxidant enzymes play an important role in maintaining the stability and resisting external biological stress of Pleurotu seryngii during the primordial period. The up-regulated DEGs during the fruiting body stage were mainly enriched in spliceosomes, steroid biosynthesis and AMPK signaling pathways, indicating that environmental factors have a certain impact on the fruiting body stage.
Gene expression at low temperature (4°C) of Pleurotus pulmonarius strain X57 was investigated by RNA-seq technology to explore the putative mechanism of low temperature response of P. pulmonarius. There were 742 differentially expressed genes after treatment at low temperature for 6h, of which 374 were up-regulated and 368 were down-regulated. After being treated for 12h, a total of 1 489 genes were differentially expressed at low temperature, among which 53% were up-regulated and 47% down-regulated. The Gene Ontology classification showed that the differentially expressed genes were mainly involved in binding, catalytic activity molecular functions and metabolic process, cellular process and biological pathway. The KEGG pathway analysis has also revealed that the differential expressed genes are mainly related to biosynthesis of amino acids, ribosomes and steroids, and nitrogen metabolism. The results also showed that genes expression related to MAPK signaling pathway was increased with the increase of low temperature treatment duration. It has been reported that the HOG-MAPK is an important pathway for MAPK pathway study in low temperature stress of fungi, which was more explicit and single in signal transmission. Bioinformatics software was used to construct HOG-MAPK pathway in P. pulmonarius, and the expression of related genes was verified by RT-qPCR. The results showed that with reference to cold stress of 0h, the expression of most genes in the pathway increased continuously with the increase of cold shock duration, and the difference was significant and was consistent with RNA-Seq analysis. A comprehensive analysis of genes expression in the cold stress period of P. pulmonarius provides a basis for further study on the functional identification of the important genes related to the cold stress and the mechanism of cold signal pathway regulation in P. pulmonarius.
L-cysteine sulfoxidelyase (C-S lyase) is a key enzyme of the characteristic flavor substance biosynthetic pathway in Lentinula edodes. In this study, based on genomic data in six strains of L. edodes, 24 C-S lyases were recognized and the physicochemical characterization, signal peptide sequencing, transmembrane domain, transcriptional activity, evolutionary development, conserved domains and 3D structure of these C-S lyases were analyzed. The results showed that all these C-S lyases have the same domain (IPR015424 and IPR000192). They belong to the same protein family (PTHR43092:SF2) and don’t contain the signal peptide and transmembrane structure. However, the stability of these proteins showed difference. Analysis of phylogenetic tree revealed that 11 C-S lyases were in the new clade with transcriptional activity in the mycelium or fruiting body of L. edodes, and had motif 19 in the allicase and L-cysteine desulfurization enzyme. It is speculated that these 11 C-S lyases are the enzymes which may effectively produce sulphur flavor compounds and endogenous formaldehyde. According to the analysis of 3D structure, the conserved motif 19 is the key domain for the catalytic activity of allicase. Further analysis indicated that this new clade could be categorized into two sub-clades: one contained the earlier reported Lecsl1/LE01_CSL1 and the other contained Lecsl homologous protein which only showed the transcriptional activity in the mycelium. These two sub-clades were presumed to be the functional C-S lyase in the mycelium growing period. The molecular dynamics simulation suggests the residue Asn3, Gln5 and Ser6 in the motif 19 play an important role in the catalytic activity of C-S lyases.
The ITS in rDNA sequence is widely used as DNA barcoding in the study of phylogentic development of fungi and identification of species. IGS could be used for identification of different strains in different species. No complete rDNA sequence has been reported in edible fungi. In this study, next-generation sequencing (NGS) and third generation sequencing (TGS) techniques were used to sequence a single monokaryon strain “6-3” of Flammulina filiformis, and the genome sequences obtained by TGS were modified by NGS data to obtain a genome sequence with better gene integrity, continuity and accuracy. In comparison with Fibroporia vaillantii rDNA sequence, the complete rDNA sequence of Flammulina filiformis was obtained. rDNA sequence analysis showed that Flammulina filiformis had eight rDNA transcriptional units with a length of 5 903bp and 9 gene spacers with considerable difference in length ranging from 3 909 to 4 566bp. In the rDNA transcription unit, the sequence length of each element are: 18S rDNA 1 796bp, ITS1 234bp, 5.8S rDNA 173bp, ITS2 291bp, and 28S rDNA 3 410bp. In intergenic spacers, IGS1 1 351-1 399bp, 5S rDNA 124bp, and IGS2 2 435-3 092bp. The accuracy of 5S, 5.8S, 18S and 28S rDNA sequences of Flammulina filiformis was verified by transcriptome data and supported by phylogenetic analysis. Multiple sequence alignment indicated that there were abundant polymorphisms in the intergenic spacer sequences (IGS1 and IGS2) of different copies. Polymorphism was derived from SNP, InDel and TRS (tandem repeat sequences), and TRS was derived from the type and number of repeating units. Among the nine intergenic spacers, IGS1 has only a small number of SNP and InDel, while IGS2 not only has SNP and InDel, but also TRS. The results suggest that conservative IGS sequences between different copies should be selected when IGS is used to identify different strains at intraspecific level.
Volvariella volvacea is one of the main types of export of local products in China. The pileus of V. volvacea fruiting bodies were easily expanded after harvest which limited the storage life and transportation distance. MADS-box transcription factor plays an important role in the regulation of plant maturation and senescence as well as the development of fungal fruiting body. At present, no relevant studies on the MADS-box transcription factors of V. volvacea have been reported. In this study, one gene Vvrin1 encoding MADS-box transcription factor of V. volvacea was identified by means of bioinformatics and molecular biology analysis on genome and transcriptome data. Vvrin1 gene is 1 392bp, containing two introns and encoding 419 amino acids. The protein contains an MADS-box domain, with sequences similar to MADS-box proteins of Agaricus bisporus, Hypsizygus marmoreus and Coprinopsis cinerea at resemblance of 71%, 67% and 61%, respectively. Digital gene expression (DGE) data and qRT-PCR data demonstrated that the expression of Vvrin1 gene in the stipe elongation stage was highest in fruiting period, showing significant difference (P<0.01). It was speculated that this transcription factor was involved in the regulation of the elongation of the stipe and the pileus expansion in V. volvacea. This study provides data supporting the regulation research of mushroom maturation and senescence, especially pileus expansion.
Septins with GTPase activity are widely found in eukaryotic organisms except for plants, and play multiple roles. Based on the local tBlastn analysis, Coprinus cinereus septin gene Cc.Cdc3 was contrasted with the genome of Agaricus bisporus, and a homologue gene in A. bisporus was identified and termed Ab.Cdc3. Alignment of Ab.Cdc3 with homologous septins revealed the presence of the conserved motifs within GTP-binding domain. Quantitative real-time PCR revealed that the expression of Ab.Cdc3 was higher in stipe than that in mycelium, primordium and caps during different developmental stages. Subsequent analysis showed that the expression of this gene in the post-harvest fruiting body was significantly higher at 0h than that at 12h and 48h. These results provide valuable reference for further investigating the function of Ab.Cdc3 during fruiting body development in A. bisporus.
Auricularia cornea is one of the most consumed edible mushrooms in China. Normally, commercial varieties of A. cornea are dark brown in colors. In 2016, combination of three kinds of fruiting bodies i.e. brown, white and white with brown patch, had been observed in A. cornea strain 43012H in a cultivating shed in Zhangzhou, China. Dikaryotic strains were isolated from these three kinds of fruiting bodies (white, brown, and variegated) and were named as AC_B (brown), AC_W (white), AC_R and AC_RW (the latter two were respectively isolated from variegated sample with brown and white patches). These isolates were inoculated separately to sawdust medium for fruiting body formation. As a result, isolate AC_B produced normal brown color fruiting bodies of A. cornea, while AC_W, AC_R and AC_RW formed white fruiting bodies. Co-culture of AC_B + AC_W, AC_B + AC_R and AC_B + AC_RW resulted in simultaneous formation of white, brown and variegated fruiting bodies in all inoculated bags. Repeated experiments obtained the same result. Genomic sequencing of AC_B and AC_W strains gained two single-nucleotide polymorphism (SNPs) sites (SNP1 and SNP2) that might be associated with the colors in fruiting bodies. Isolates with brown fruiting bodies had the genotype of heterozygous SNP1 (A/G) and homozygous SNP2 (A), while isolates with white fruiting bodies homozygous SNP1 (G) and heterozygous SNP2 (A/C).
Morel domestication and cultivation technology has made great progress in China in recent years. However the weak biological basic research has limited the stable and high yield of the morel cultivation. So far, there are no reports on evaluation of germplasm resources of Morchella species all over the world. In this study, ITS phylogenetic and RAPD cluster analysis were carried out on the 36 representative cultivated Morchella strains collected from 12 provinces in China. The results showed that combining with effective reference sequence, the ITS sequence seemed very good to distinguish and identify the tested strains, of which 26 were identified as M. importuna, and 10 M. sextelata. 14 RAPD polymorphic primers were selected from 40 primers for genetic diversity analysis of test strains and 124 polymorphic bands were amplified among 36 strains. Though UPGMA cluster 36 test strains can be divided into two groups, separately corresponding to M. improtuna and M. sextelata, being consistent with the ITS phylogeny analysis results. The percentage of polymorphic populations of M. importuna group was higher than that of M. sextelata group. The unique characteristic bands were amplified by OPA17 and OPA18 primers on AA02 and AA15 strains were designed respectively to species specificity RAPD-SCAR markers, which could quickly and effectively identify AA02 and AA15 strains among 36 cultivated strains. It was proved that ITS sequence could be used for identification of the species of Morchella cultivated strains, and the genetic diversity of the cultivated strains could be evaluated systematically by RAPD. The feasibility of transforming the RAPD random molecular marker into the characteristic SCAR marker of Morchella strains was confirmed.
Flammulina filiformis is one of mushrooms with high nutritional and health value. Its yield and quality is determined by the length of the stipe. However, the related enzymes and molecular mechanism of the stipe elongation are still unclear. Previous investigation indicated that exo-β-1,3-glucanase gene (exg2) was associated with the elongation of stipe in Volvariella volvacea, however, there is no report about the exg gene in F. filiformis. In this study, three exo-β-1,3-glucanase family genes (named as Ffexg1, Ffexg2 and Ffexg3) were identified in the whole genome of F. filiformis, and the clone verification was Successful. Quantitative PCR was used to analyze the expression patterns of the three Ffexg genes at different developmental stages or tissues of F. filiformis fruiting bodies. The results showed that Ffexg1 was highly expressed in the stipe specifically. The transcription levels of Ffexg2 and Ffexg3 first increased and then decreased in the stipe, and gradually increased in the pileus. The three Ffexg genes were significantly expressed in elongating parts of the stipe, especially at notably bending part when horizontal placement of the fruiting bodies. It was indicated that there were temporal and spatial differences in the expression of the three Ffexg genes in F. filiformis, and the rapid elongation period of the stipe was accompanied by the higher transcription of the Ffexg genes. The Ffexg family gene may act on the β-1,3-glucan chain, a major component of cell wall, playing a role in the development of stipe and pileus in F. filiformis.
The effects of catalase and copper-zinc superoxide dismutase genes in Pleurotus eryngii under temperature stress were investigated. The catalase (CAT) and copper-zinc superoxide dismutase (Cu/Zn-SOD) genes were cloned by RT-PCR and their expression levels under high and low temperature stress were analyzed by real-time PCR. The results showed that the open reading frames of CAT and Cu/Zn-SOD genes were 1 581bp and 582bp, encoding 526 and 193 amino acids, respectively. The molecular weight of amino acids were 59.6kDa and 19.62kDa and the isoelectric points were 6.35 and 6.31, respectively. Under high temperature (35°C) and low temperature (4°C) treatment, the expression levels and enzyme activities of CAT and Cu/Zn-SOD genes reached the highest in 48h and both of them showed significant difference in comparison with untreated group, indicating CAT and Cu/Zn-SOD genes played an important role in the process of resisting temperature stress.
In order to explore the mechanism of kojic acid (KA) responsible for increase in yield of fruiting body of Hypsizygus marmoreus, the effect of addition of KA in different mycelial growth period on fruiting was investigated. It was found that too short or too long mycelial growth period was unfavourable for KA on increasing production, and suitable time of addition of KA for increasing yield was in mycelial growth period of 60-80d. It was also found KA could improve the mycelial utilization rate of lignocellulose in substrate, and the activities of laccase and cellulase were regulated by KA at different developmental stages of the fungus. Laccase activity was lower at mycelial regeneration and pigmentation stages after KA treatments, but it was higher at primordium, pinhead and fruiting stages as compared with experimental control. The cellulase activities were higher at total developmental stages under KA treatments, being 3.16-fold increase at fruiting body stage as compared with the control. The expression level of laccase gene and cellulase gene was analyzed. It was showed that the expressions of laccase and cellulase genes were up-regulated in varying degrees after KA treatments, showing consistency with the result of enzyme activity. These results indicated that exogenous KA could increase laccase and cellulase activities in the substrate, and thereby increase mycelial lignocellulose utilization, providing more energy for fruiting body development to achieve the purpose of increasing the production of fruiting bodies of Hypsizygus marmoreus.
The “cicada flower”, i.e., the dead cicada nymphs parasitized by Cordyceps cicadae, is one of the valued traditional Chinese medicines that has been using to treat chronic nephritis. However, its bioactive components are still poorly investigated. In this study, the ethyl acetate extracts of the fruiting bodies of C. cicadae harvested from an artificial medium were sequentially separated by using silica gel column, Sephadex LH-20 resin column, ostadecylsilane column and high performance liquid chromatography. Three compounds were purified and structurally determined as (E,E)-9-oxooctadeca-10,12-dienoic acid (1), ergosterol (2), and bassiatin (3) by spectroscopy analysis. Among them, compound 1 was isolated from C. cicadae for the first time. Antimicrobial assays indicated that the compounds 1 and 3 showed obviously antibacterial activities against Bacillus subtilis and Escherichia coli, and antifungal activity against Candida albicans. Compound 2 only demonstrated considerable antibacterial activities. The data of this study advanced the understanding of the bioactive constituents of C. cicadae.
Comparison of the quality of different Cordyceps militaris fruit body samples was made, based on comparing the active compositions. The content of polysaccharide, nucleosides, free alditol and low molecular weight sugar in the fruit bodies from 17 different C. militaris strains and 16 samples on market were determined and their HPLC spectrum of nucleosides were compared. Results indicated that the active components in C. militaris fruit bodies varied with different strains. The strain quality had great influence on the content of cordycepin and N 6-(2-hydroxyethyl) adenosine. The difference between the lowest and the highest content of cordycepin in the samples reached fourteen fold, while that of N 6-(2-hydroxyethyl) adenosine more than six fold. The nucleoside analysis of C. militaris samples on the market also indicated the great variation of cordycepin content. The content of polysaccharide, mannitol and trehalose in fruit bodies of 17 strains was 1.81%-4.92%, 1.44%-4.47% and 3.58%-25.43% respectively, while that in 16 samples on the market was 2.84%-8.55%, 0.96%-3.93% and 1.04%-19.91%, respectively. Fruit body quality was comprehensively evaluated based on data normalization method. Fruit bodies of strains G7a, G10a and G15a had good comprehensive quality with most of the components beyond the average values, indicating these strains were suitable for producing high quality C. militaris fruit bodies.
The antioxidative capacity and monosaccharide composition of the polysaccharide from the fruiting body of Panus giganteus were analyzed. The scavenging ability in vitro to hydroxyl radical, 1,1-diphenyl-2-picrylhydrazyl, DPPH free radical, superoxide anion radical, 2,2?-azino-bis(3-ethylbenzothiazoline)-6-sulfonic acid, ABTS free radical and iron ion reducing ability were explored. Human liver cell line LO2 was used as a material to establish a model of hydrogen peroxide cell oxidative damage, and the anti-oxidation ability of fruiting bodies of Panus giganteus at the cellular level was explored. The monosaccharide content and composition of the polysaccharide in the fruiting bodies were also detected by phenol sulfuric acid method and HPLC. The results of antioxidant activity test showed that the polysaccharides of Panus giganteus had strong scavenging ability to hydroxyl radicals, superoxide anions, DPPH free radicals and ABTS free radicals, and also had high iron ion reducing ability. The results of intracellular antioxidant activity assay indicated that Panus giganteus polysaccharide had protective effect to oxidize H2O2 in hepatocyte LO2, and could significantly increase the activity of catalase (CAT) (P<0.01) and superoxide dismutase (SOD) in the damaged cells at 10mg/mL (P<0.01); The main monosaccharide content of the active polysaccharides in the fruiting body of Panus giganteus included glucose (2 985.50mg/kg), mannose (1 867.23mg/kg), xylose (814.98mg/kg), galactose (724.24mg/kg), and fucose (443.72mg/kg), glucose aldehyde (419.41mg/kg), L-rhamnose monohydrate (81.18mg/kg), L-arabinose (64.40mg/kg), ribose (39.95mg/kg), and galactose aldehyde (24.40mg/kg). The results of this study provide basic data for the industrial popularization and commercial development of Panus giganteus.
The impact of ≥0°C accumulated temperature on the growth development of Morchella importuna was investigated. The ≥0°C accumulated air temperature (AAT) and the ≥0°C accumulated soil temperature (AST) of multiple morel cultivation sites at different altitudes were analyzed by applying the agriculture meteorological methodologies and statistical approaches. The results showed that, although the morels at different altitudes differed in growth periods, no significant AAT or AST difference was observed across the site investigated. The AATs in the period of spawn growth and primodium differentiation, the period of fruitbody maturation and the period from primodium formation to fruitbody maturation were (563±21)°C·d, (712±20)°C·d, and (149±21)°C·d, respectively. The ASTs were found having remarkable difference across the different cultivation sites when data from the same depth soils (0cm, 5cm, 10cm) were compared accordingly. This study found that the AST of 5cm depth soil could be used as a reference indicator for the heat energy demand for morel growth, the recorded ASTs range for the period of spawn growth and primodium differentiation, the period of fruitbody maturation and the period from primodium formation to fruitbody maturation were (741±36)°C·d, (915±46)°C·d, and (174±23)°C·d, respectively.
Heat stress affects the quality and production of Lentinula edodes. In this study, using sensitive-heat strain YS3357 of L. edodes as tested strain, the alleviative effects of exogenous auxin and auxin analogues on heat-induced oxidative damage in Lentinula edodes under heat stress were investigated. The results indicated that exogenous IAA, NAA and 2,4-D improved dramatically the thermotolerance of the sensitive-heat strain YS3357. Exogenous auxin and auxin analogues could suppress the generation of O 2-, decrease the activity of LOX and the content of TBARS, and improve the activity of SOD, which have relations with alleviating the effect of oxidative damage induced by heat stress on the mycelia of Lentinula edodes. This study mainly explored the effects of exogenous auxin and auxin analogues on the mycelial growth, physiological capacity and resistance to oxidative stress for the sensitive-heat strain YS3357 under heat stress, providing the theoretical foundation on further illumination of the mechanism of resistance-heat stress for the edible fungi.
The effects of different culture substrates on nutritional and flavor components of Volvariella volvacea dried fruiting bodies are investigated under identical cultivation condition. Five kinds of material, rice straw (ST), cotton waste (CW), cotton seed hull (CS), spent cultivating substrate of Flammulina velutipes (SF), and spent cultivating substrate of Pleurotus eryngii (SP), were used as experimental substrate. Nutrient component detected includes crude protein and hydrolytic amino acid, and taste substance detected includes soluble sugar, organic acid, free amino acid and umami 5′-nucleotides. The results showed that the content and composition of crude protein and hydrolyzed amino acid were superior, using CS as cultivating substrate. The highest content of soluble sugar alcohol and organic acid occurred in fruiting bodies cultivated with ST substrate. Equivalent umami concentration (EUC) value of fruiting bodies cultivated in five kinds of substrate ranged from 317.45 to 708.75g MSG/100g. The highest EUC value occurred in fruiting bodies cultivated with CS substrate; EUC value of fruiting bodies cultivated with SP substrate took second place, while the EUC value of fruiting bodies cultivated with SF substrate was the lowest [(317.45±13.67)g MSG/100g], about 44.79% of those cultivated with CS substrate. Our results indicated that cultivating substrate had a great effect on the flavor component of Volvariella volvacea.
Melanin is one of biological pigment widely existing in animals, plants, bacteria and fungi, with broadly biological functions and activity. Auricularia heimuer is known as “black”, and its melanin component is worthy of development and application. This study aims at evaluation of the improvement effects of Auricularia heimuer melanin on acute liver injuried mice. Extraction of Auricularia heimuer was analysed by fourier transform infrared spectrometer and its antioxidant activity in vitro was verified by scavenging free radical of 1,1-diphenyl-2-picrylhydrazyl (DPPH) and hydroxyl radical. CCl4-induced acute liver injury model was established, and the antioxidant in vivo and liver improvement effects of Auricularia heimuer melanin were assessed by determining the change of serum enzyme, liver function index and the histological examination of the liver tissue. The result showed that extraction of Auricularia heimuer had the same functional groups and antioxidant activity in vitro as melanin reported in literature, with the EC50 values of scavenging DPPH and OH radical of 0.0887mg/mL and 2.2030mg/mL respectively. In vivo, Auricularia heimuer melanin had significantly reduced levels of ALT and AST in serum and preserved activities of SOD, inhibited MDA in liver, and improved the damages of the liver tissue. The study discovered that Auricularia heimuer melanin had efficiently improved CCl4-induced acute liver injury in vivo, providing a new direction for exploration of Auricularia heimuer melanin functional product.
The inhibition effect on SW620 colon cancer cells of ethanol extract of Sanghuangporus sanghuang fruiting bodies was studied. The proliferation rate was determined by alamarBlue? method. The early apoptosis was determined by annexin V/Propidium iodide (PI) double staining and flow cytometry analysis. The cell cycle was determined by PI staining and flow cytometry analysis. Release of reactive oxygen species (ROS) by SW620 cells was determined by 2′,7′-dichlorofluorescin diacetate (H2DCFDA) probe and flow cytometry analysis. The results indicated that SW620 colon cancer cells treated with ethanol extract of S. sanghuang fruiting bodies were significantly inhibited at the concentration of 12.5-100μg/mL, while no cytotoxic effects on CHO cells and macrophages were detected. Flow cytometry analysis revealed that the ethanol extract of S. sanghuang fruiting bodies increased SW620 cell apoptosis, and decreased the number of cells in G0/G1 and G2/M phases of cell cycle in a concentration-dependent manner and the apoptosis was related to the release of ROS by SW620 cells.
Effects of complex organic nitrogen sources on triterpene liquid submerged fermentation of Ganoderma lingzhi were studied based on previous research, using different yeast as nitrogen source. The effects of different yeast during fermentation process on production of triterpenes were investigated by single-factor experiment so as to determine the optimum concentration range of yeast. According to the central composite design, two or three kinds of yeast were combined for the optimization of fermentation medium, and the best ratio of composite organic nitrogen source was optimized. The results showed that when 6.6g/L of N-1 and 6.6g/L of N-2 were added to the basic medium, the yield of Ganoderma triterpene was 0.478g/L (theoretical yield was 0.485g/L), respectively about 21%, 139%, and 103% higher than the addition of yeast N-1, N-2, and N-3 alone. The concentration of nitrogen was the lowest when combinations of two kinds of yeast were used. When the added amounts of N-1, N-2 and N-3 in the basic medium were espectively 5.07g/L, 3.78g/L, and 7.63g/L, the yield of Ganoderma triterpene reached 0.514g/L (theoretical yield was 0.510g/L), respectively 30%, 157%, and 74% higher than the single factor control group. Optimized replenishment of the complex nitrogen source can significantly improve the yield of triterpenes produced by Ganoderma lingzhi based on liquid submerged fermentation, and our results provide a scientific basis for the large-scale production of Ganoderma triterpene under liquid submerged fermentation.
Hyperlipidemia, a most common form of dyslipidemia with abnormally elevated lipid or lipoprotein levels in the blood, has been regarded as one of major risk factors for cardiovascular disease. Previous studies have demonstrated that polysaccharides from Pleurotus eryngii (king oyster mushroom) are capable of inhibiting lipid accumulation in the cells, in the mice and zebrafish animal models. In this study, polysaccharides were obtained from Pleurotus eryngii mycelium by solid-state fermentation using lignocellulosic waste, corn-cob and wheat bran as substrate. Lipid-lowering efficiency and mechanism of the polysaccharides were detected in zebrafish larva and adult models. It was indicated that polysaccharides obtained from Pleurotus eryngii mycelium solid-state fermentation (PESF) had in vivo activity of reducing lipid accumulation in the body of zebrafish larvae fed with high fat diet (HFD), and significantly decreasing accumulation of lipid in livers through blocking intestinal lipid attachment and absorption in both zebrafish larva and adult models. Our findings suggest that PESF can be used as a valuable lipid-lowering food additive or raw materials for producing lipid-lowering drugs for hypolipidemic and hepatoprotective treatments.
Active substance from fruiting body of Hericium erinaceus was extracted using supercritical CO2 fluid technology, and the effects of the extraction pressure and CO2 flow rate in process of extraction and separation on extract yields were investigated by orthogonal experiment. The optimal conditions were extraction pressure of 30MPa at 45°C, extraction duration of 1.5h, and carbon dioxide flow rate of 20g/min. The ratio of entrainer (ethanol) to H. erinaceus fruiting body weight was 5:1 (mL:g). Under these conditions, crude extract yield was 2.78%. The supercritical fluid CO2 extracts of H. erinaceus fruiting bodies showed better antioxidant capability in vitro and anti-tumor activity as compared with ethanol extraction. These results provide fundamental data for exploiting functional products of the fungus.
This paper reports the revised method of determining the Ganoderma triterpenoids by UV-Vis absorption spectroscopy based on the colorimetric reaction between triterpenoid with perchloric acid and vanillin, from this method the standard curves are derived and optimized. Several main triterpenoids purified from Ganoderma lingzhi fruiting body were analyzed, and our results showed that if coleanolic acid was used as standard to evaluate the triterpenoids, the detection results were far below the true values. Spectral analysis was proved that better linear relationship of the standard curve could be obtained by integrating the area of the UV-visible absorption bands.
Mycorrhiza helper bacteria (MHB) in rhizosphere soil of Pinus thunbergii and Boletus edulis (Be), were isolated, and their positive effect on growth of ectomycorrhizal fungus Be was investigated. The effect of Be and MHB co-inoculation on pine seedling height, ground diameter of stem, stem root ratio, seeding dry weight and root infection rate was also observed. The result revealed that the metabolites of bacterial strains B2 and K2 significantly promoted in vitro hyphal growth of Be. Co-inoculation of Be+B2 and Be+K2 in pot experiment showed that stem root ratio decreased by 46.41% and 35.40% respectively. However, seedling height, ground diameter, dry weight, root infection rate increased by 17.71% and 16.82%, 41.65% and 35.6%, 44.71% and 48.78%, and 23.2% and 21.5%, respectively. It was concluded that B2 and K2 can be considered as MHB strains. B2 and K2 were identified as Bacillus cereus based on morphological, physiological, and biochemical analyses in combination with analysis of 16S rDNA gene sequences. Bacillus cereus is expected to be developed as biological fertilizer in colonized soil of Boletus edulis.
