Development of a Molecular Marker Linked to the A4 Locus and the Structure of HD Genes in Pleurotus eryngii

Allelic differences in A and B mating-type loci are a prerequisite for the progression of mating in the genus Pleurotus eryngii; thus, the crossing is hampered by this biological barrier in inbreeding. Molecular markers linked to mating types of P. eryngii KNR2312 were investigated with randomly amplified polymorphic DNA to enhance crossing efficiency. An A4-linked sequence was identified and used to find the adjacent genomic region with the entire motif of the A locus from a contig sequenced by PacBio. The sequence-characterized amplified region marker 7-2299 distinguished A4 mating-type monokaryons from KNR2312 and other strains. A BLAST search of flanked sequences revealed that the A4 locus had a general feature consisting of the putative HD1 and HD2 genes. Both putative HD transcription factors contain a homeodomain sequence and a nuclear localization sequence; however, valid dimerization motifs were found only in the HD1 protein. The ACAAT motif, which was reported to have relevance to sex determination, was found in the intergenic region. The SCAR marker could be applicable in the classification of mating types in the P. eryngii breeding program, and the A4 locus could be the basis for a multi-allele detection marker.

Extraction and in vitro antioxidant activity of exopolysaccharide by Pleurotus eryngii SI-02

The extraction parameters for Pleurotus eryngii SI-02 exopolysaccharide (EPS) produced during submerged culture were optimized using response surface methodology (RSM). The optimum conditions for EPS extraction were predicted to be, precipitation time 20.24 h, ethanol concentration 89.62% and pH 8.17, and EPS production was estimated at 7.27 g/L. The actual yield of EPS under these conditions was 7.21 g/L. The in vitro antioxidant results of the EPS showed that the inhibition effects of EPS at a dosage of 400 mg/L on hydroxyl, superoxide anion and 1,1-diphenyl-2-picrylhydrazyl (DPPH) radicals were 59.63 ± 3.72%, 38.69 ± 2.59%, and 66.36 ± 4.42%, respectively, which were 12.74 ± 1.03%, 8.01 ± 0.56%, and 12.19 ± 1.05% higher than that of butylated hydroxytoluene (BHT), respectively. The reducing power of EPS of P. eryngii SI-02 was 0.98 ± 0.05, 60.66 ± 5.14% higher than that of BHT. The results provide a reference for large-scale production of EPS by P. eryngii SI-02 in industrial fermentation and the EPS can be used as a potential antioxidant which enhances adaptive immune responses.

Isolation of Fungal Pathogens to an Edible Mushroom, Pleurotus eryngii, and Development of Specific ITS Primers

Fungal pathogens have caused severe damage to the commercial production of Pleurotus eryngii, the king oyster mushroom, by reducing production yield, causing deterioration of commercial value, and shortening shelf-life. Four strains of pathogenic fungi, including Trichoderma koningiopsis DC3, Phomopsis sp. MP4, Mucor circinelloides MP5, and Cladosporium bruhnei MP6, were isolated from the bottle culture of diseased P. eryngii. A species-specific primer set was designed for each fungus from the ITS1-5.8S rDNA-ITS2 sequences. PCR using the ITS primer set yielded a unique DNA band for each fungus without any cross-reaction, proving the validity of our method in detection of mushroom fungal pathogens.

Effect of Pleurotus Eryngii Polysaccharide on Learning and Memory Ability and Antioxidant of Aging Mice Induced by D-galactose / 中国康复理论与实践

@#Objective To study the effect of Pleurotus eryngii polysaccharide on aging mice induced by D-galactose (D-gal). Methods 72 ICR mice were divided into high, moderate, and low dosages (of polysaccharide) groups, piracetam group, model group, and control group, 12 in each group. The model of aging mice was induced with D-gal. They were tested with Y-maze, and the contents of superoxide dismutase (SOD), malondialdehyde (MDA), lipofuscin and L-glutamate in cerebrum were determined 6 weeks after model. Results Compared with the model group, the achievement of Y-maze improved, the activities of SOD increased and the content of MDA and lipofuscin decreasd in high and moderate dosage groups (P<0.05), while the mass of brain and kidney increased and the L-glutamate decreased in the high dosage group (P<0.05). Conclusion Pleurotus eryngii polysaccharide can ameliorate aging of mice induced by D-gal.

Screening of Cell Cycle-Related Genes of Pleurotus eryngii Using Yeast Mutant Strains

Temperature-sensitive yeast mutants were used to screen for cell cycle-related genes from Pleurotus eryngii genomic DNA. A mushroom genomic DNA library was established and each gene was screened for the ability to rescue seven Saccharomyces cerevisiae temperature-sensitive strains. Hundreds of yeast transformants were selected at restrictive temperatures over 30degrees C. Plasmids from the transformants that survived were isolated and transformed back into their host strains. The temperature sensitivity of the resulting transformants was tested from 30degrees C to 37degrees C. Ten DNA fragments from P. eryngii were able to rescue yeast temperature-sensitive strains, and their DNA sequences were determined.

Determinación de la eficiencia de dos tratamientos térmicos usados en paja de trigo para el cultivo de Pleurotus eryngii / Determination of the efficiency, of two thermal treatments used in wheat straw for the culture of Pleurotus eryngii

Como parte de una posible producción de basidiocarpos de Pleurotus eryngii en Chile, se seleccionó como sustrato paja de trigo. Como objetivo principal se evaluó la eficiencia de dos tratamientos térmicos, para reducir la carga microbiana del sustrato, además de determinar los cambios en la relación C:N antes y después a los tratamientos térmicos y cosechas de basidiocarpos. Al mismo tiempo, se determinó la eficiencia biológica de P. eryngii. En un primer tratamiento, partidas del sustrato fueron sometidas a ebullición directa por 1 h., y en un segundo se usó la pasteurización por 3 horas. El sustrato de ambos tratamientos se depositó en bolsas de nylon de 8 Kg y se sembraron con ®semilla¼ de P. eryngii y se incubaron hasta la obtención de basidiocarpos. Se determinó en el sustrato el C y N según Saavedra (1975), y la celulosa, hemicelulosa, lignina y extraíbles totales según métodos propuestos por las normas Tappi (2000). La mayor eficiencia biológica con P. eryngii, se logró en el sustrato sometido a pasteurización.

In an attempt to get a possible production of Pleurotus eryngii basidiocarps, wheat straw was selected as a substratum. The main purpose was to assess the efficiency of two thermal treatments in order to reduce the microbial load of the substratum as well as to detect any change in the C:N relation prior and after thermal treatments and basidiocarp harvests. Besides the biological efficiency of P.eryngii was determined. In a first treatment, some parties of the substratum were submitted to direct boiling for 1h. while in a second one, pasteurization was used for 3h. The resulting substrata of both treatments were kept in 8-kg nylon bags and then sowed with P.eryngii ®seed¼and later on incubated in order to get basidiocarps. C and N were determined in the substratum according to Saavedra (1975) while cellulose, hemicellulose, lignin and removable totals were determined following the methods proposed by Tappi standards (2000). The substratrum submitted to pasteurization revealed the highest biological efficiency with P.eryngii.

Vegetative Growth and Phylogenetic Relationship of Commercially Cultivated Strains of Pleurotus eryngii based on ITS sequence and RAPD

Pleurotus eryngii, known as king oyster mushroom has been widely used for nutritional and medicinal purposes. This study was initiated to screen the suitable conditions for mycelial growth and to determine the phylogenetic relationship of the selected strains. Optimal mycelial growth was observed at 30degrees C and minimum mycelial growth observed at 10degrees C. This mushroom tolerates a broad pH range for mycelial growth, with most favorable growth observed at pH 6. Results also indicated that glucose peptone, yeast malt extract and mushroom complete media were favorable growth media, while Hennerberg and Hoppkins media were unfavorable. Dextrin was the best and xylose the least effective carbon sources. Results revealed that inorganic nitrogen sources were less effective than organic sources for the mycelial growth of P. eryngii. Investigation of genetic diversity is necessary to identify the strains. The ITS region of rDNA were amplified using PCR. The size of the ITS1 and ITS2 regions of rDNA from the different strains varied from 214 to 222 bp and 145 to 236 bp, respectively. The sequence of ITS2 was more variable than that of ITS1, and the 5.8S sequences were identical. A phylogenetic tree based on the ITS region sequences indicated that selected strains could be classified into six clusters. Fourteen IUM and ATCC-90212 strains were also analyzed by RAPD with 20 arbitrary primers. Fourteen of these primers were efficiently amplified the genomic DNA. The number of amplified bands varied with the primers and strains, with polymorphic fragments in the range from 0.2 to 2.3 kb.

Anti-tumor Effects of Exo- and Endo-biopolymers Produced from Submerged Cultures of Three Different Mushrooms

The anti-tumor effects of exo- (EX) and endo-biopolymers (EN) produced from submerged mycelial cultures of Ganoderma applanatum (GA), Collybia confluens (CC), and Pleurotus eryngii (PE) were studied using Sarcoma 180 bearing mice. Solid tumor growth was inhibited most effectively when 40 mg/kg body weight (BW) of GA-EX or PE-EN was administered to the intraperitoneal (i.p.) cavity of BALB/c mice. The spleen and liver indexes were increased in mice following i.p. administration of GA-EX and PE-EN fractions. GA-EX and PE-EN reduced the tumor formation by 30.7% and 29.4%, respectively. GA-EX and PE-EN increased the natural killer (NK) cell activity of splenocytes by 41.3% and 28.9%, respectively.