Showing papers on "Volvariella volvacea published in 2004"

Molecular cloning of a new laccase from the edible straw mushroom Volvariella volvacea: possible involvement in fruit body development.

Abstract: Cloning of a laccase-encoding cDNA from the edible straw mushroom, Volvariella volvacea, was performed using reverse transcriptionpolymerase chain reaction (RT-PCR) and rapid amplification of cDNA ends. The cDNA of the putative laccase gene (lac4) consisted of 1689 bp, including an open reading frame encoding a 23-amino acid signal peptide at the N-terminal end and a 540-amino acid mature protein with a predicted molecular mass of 58 173 Da and a pI value of 6.1. The 10 histidine residues and one cysteine residue required to co-ordinate the four copper atoms at the active site of the protein were all conserved. The amino acid sequence of V. volvacea lac4 has a high degree of identity with other basidiomycete laccases. Transcription of the laccase gene was analysed by RT-PCR and, unlike many other laccase genes, shown to be regulated independently of either copper or aromatic compounds under the test conditions. However, the laccase gene is strongly expressed during that part of the mushroom developmental cycle involving fruit body morphogenesis. : 2003 Federation of European Microbiological Societies. Published by Elsevier B.V. All rights reserved.

Biochemical and molecular characterization of a laccase from the edible straw mushroom, Volvariella volvacea

Abstract: We have isolated a laccase (lac1) from culture fluid of Volvariella volvacea, grown in a defined medium containing 150 µm CuSO4, by ion-exchange and gel filtration chromatography. Lac1 has a molecular mass of 58 kDa as determined by SDS/PAGE and an isoelectric point of 3.7. Degenerate primers based on the N-terminal sequence of purified lac1 and a conserved copper-binding domain were used to generate cDNA fragments encoding a portion of the lac1 protein and RACE was used to obtain full-length cDNA clones. The cDNA of lac1 contained an ORF of 1557 bp encoding 519 amino acids. The amino acid sequence from Ala25 to Asp41 corresponded to the N-terminal sequence of the purified protein. The first 24 amino acids are presumed to be a signal peptide. The expression of lac1 is regulated at the transcription level by copper and various aromatic compounds. RT-PCR analysis of gene transcription in fungal mycelia grown on rice-straw revealed that, apart from during the early stages of substrate colonization, lac1 was expressed at every stage of the mushroom developmental cycle defined in this study, although the levels of transcription varied considerably depending upon the developmental phase. Transcription of lac1 increased sharply during the latter phase of substrate colonization and reached maximum levels during the very early stages (primordium formation, pinhead stage) of fruit body morphogenesis. Gene expression then declined to ≈ 20–30% of peak levels throughout the subsequent stages of sporophore development.

Volvariella volvacea lectin activates mouse T lymphocytes by a calcium dependent pathway.

Abstract: The immunomodulatory lectin, Volvariella volvacea lectin (VVL), isolated from the edible mushroom, Volvariella volvacea, has been shown to stimulate the expression of Th1 cytokines and the proliferative activity of mouse splenocytes (She et al. [1998]: Biochem Biophys Res Comm 247:106-111). In order to elucidate the mechanisms underlying these activities, we conducted a kinetic analysis of the early and late activation markers in mouse T lymphocytes: (1) flow cytometric analysis of calcium influx, (2) induction of activation molecules (CD25 and CD69), (3) expression and DNA-binding activity of the nuclear factor of activated T cells (NFAT), NFkappaB, and activation protein-1 (AP-1), (4) translational production of cytokines (interleukin-2 (IL-2) and interferon-gamma (IFNgamma)), and (5) cell proliferation by expression of proliferating cell nuclear antigen (PCNA) and tritiated thymidine incorporation. All results showed that VVL induced a rapid expression of CD69, CD25, NFAT, IL-2, and PCNA in a dose- and time-dependent manner, leading to lymphocyte proliferation. These effects brought about by VVL were more potent than those stimulated by equimolar concentrations of mitogenic lectin, concanavalin A (Con A). Cell activation and proliferation were mediated through a calcium-dependent pathway as demonstrated by a VVL-induced increase of intracellular calcium influx, and a proliferation inhibition by the Ca-dependent phosphatase calcineurin blocker-cyclosporin A (CsA). Taken all data together, VVL is a lectin which activates lymphocyte through successive calcium influx, nuclear localization of NFAT transcription factor, induction of activation markers, CD25 and CD69, intracellular cytokine production, and cell proliferation.

Mushroom cryopreservation and its effect on survival, yield and genetic stability.

Abstract: Mycelial stock cultures of Agaricus bisporus, A. Bitorquis, Pleurotus flabellatus, P. Sajor-caju, P. Ostreatus, P. Sapidus, Auricularia polytricha, Lentinula edodes, Morchella esculenta and Volvariella volvacea were maintained by frequent subculturing at an interval of two months and separately as wheat grain spawn in liquid nitrogen with 15 percent glycerol. Preservation of mushroom stock cultures as wheat grain spawn under liquid nitrogen proved to be the better method of maintenance. The percent recoveries of stored samples were unchanged from the first recovery after six months to the last recovery after 42 months in nine out of 11 stock cultures preserved under liquid nitrogen. However, a marginal decline in survival of 10 % was recorded in Auricularia polytricha and Volvariella volvacea. Yields before preservation of mushroom stock cultures and after 30 months of preservation exhibited static biological efficiency and fruitbody weight. The comparison of Random Amplified Polymorphic DNA (RAPD) and Internal Transcribed Spacers (ITS) PCR amplified products did not exhibit DNA fragment variation in banding patterns at the intraspecific level during preservation of stock cultures by either method. The modified cryopreservation protocol and experimental demonstration of genetic stability of stock cultures reported here validate the use of mushroom cryopreservation techniques and supports studies on genetic stability of preserved biological materials.

ISOLATION OF COLD INDUCED GENES BY MODIFIED cDNA-AFLP WITH SINGLE ENZYME DIGESTION FROM VOLVARIELLA VOLVACEA

Abstract: Ten cold induced gene fragments VC7, VC8, VC9, VC10, VC11, VC12, VC13, VC14, VC15, VC16 were isolated from Volvariella volvacea by modified cDNA-AFLP with single enzyme digestion. DNA sequence results revealed that these DNA fragments had 504bp, 549bp, 555bp, 301bp, 189bp, 602bp, 605bp, 834bp, 703bp, 1085bp respectively. BLAST search results showed that VC7, VC8, VC9, VC10, VC11, VC12, VC13, VC15, VC16 had no significant homologous nucleotide sequences found in the databases yet except that VC14 was highly homologous with Neurospora crassa partial nca-1 gene for calcium P-type ATPase. Translated protein sequences of VC7, VC8, VC9, VC10, VC12, VC13, VC14, VC16 had high similarities to some corresponding protein sequences of Neurospora crassa, Schizosaccharomyces pombe and Streptomyces avermitilis, while translated protein sequences of VC11 and VC15 had no significant homologous protein sequences found in the databases yet.

Metal levels in mushrooms consumed in southwestern Nigeria

Abstract: Seven mushroom species, Volvariella volvacea, Termitomyces robustus, Termitomyces mammiformis, Schiwphyllum commune, Termitomyces globulus, Pleurotus squarrosulus and Auricularia auricular, obtained from different areas of Akure South Local Government Area were analyzed for their elemental concentrations. The predominant element was potassium (920-3590 mg/100g). Other nutritious elements, such as Ca, Na, Mg, P and Mn, were found in moderate quantities. Values of the heavy metals Pb, Zn and Cu were low, while Cd was not detected. Also Pb/Zn ratio of all the samples was relatively low according to the low traffic density in this part of the country.

Selection for cold-resistent strain by complex mutagenesis of volvariella volvacea and identification of the strain

Abstract: The protoplasts of Volvariella volvacea prepared under optimum conditions were mutated by UV irradiation, 60Co-γrays and DES.The mutant VH which could survival about 10 days in 4℃ was obtained. The biological efficiency of VH was higher than control strain at significant difference level. Biochemistry analysis results showed variation existed between VH and control strain on both zymogram and activity of peroxidase isoenzyme and esterase isoenzyme. The mutation coefficient was 0.213 by RAPD analysis. The morphological character of fruiting body was normal, it tasted delicious with no toxicity. Amino acid analysis results showed that contents of total amino acids and Glu were higher than control strain, the others had no significant difference. The strain VH was genetically stable and had potential value.

Effect of different temperature treatments on proteinase activities of Volvariella volvacea and Pleurotus cornucopiae

Abstract: The straw mushrooms(Volvariella volvacea and Pleurotus cornucopiae) were stored under different temprerature, that is 4, 15,30 ℃,to demonstrate their protein and proteinase activity changes.The experiemental results showed that,the later the proteinase activity peak appeared ,the longer the mushrooms kept fresh.The suitable store temperatures were 15 ℃ for Volvariella volvacea to keep fresh within 3 days and 4 ℃ for Pleurotus cornucopiae to keep fresh within 7 days. While the mushrooms were stored at the other temperatures, the time for them to keep fresh was very short(1 day).This indicated that variations in the proteinase activities were closely related to these effects of keeping fresh in both mushrooms.