Aislamiento y producción de basidiomas de cepas nativas de Volvariella bombycina (Schaeff) Singer, utilizando desechos agrícolas / Isolation and production of basidiomes from native strains of Volvariella bombycina (Schaeff) Singer, using agro-industrial wastes

Volvariella bombycina es una especie de hongo saprófito comestible que crece en troncos de árboles muertos y sobre la cual existe abundante información acerca de su sabor y propiedades nutricionales y medicinales. En Guatemala esta especie se consume en diversas regiones templado-cálidas del país, pero a la fecha no existe ningún estudio sobre su cultivo a nivel local. La presente investigación se realizó con el fin de conocer el comportamiento de tres cepas guatemaltecas de V. bombycina cultivadas en desechos agroindustriales. Las cepas fueron aisladas de basidiomas recolectados en bosques cercanos a la Ciudad de Guatemala, utilizándose medio PDA para el aislamiento y temperatura de 30 ºC para incubación. En la producción de inóculo se calculó la tasa de extensión radial (RER) sobre granos de sorgo y trigo en cajas de Petri. Para la obtención de basidiomas se evaluaron seis sustratos de desechos agrícolas: pasto jaraguá, caña y olote de maíz, rastrojo de frijol, paja de trigo, paja de arroz y tronco de tonché (Ipomoea murucoides), en frascos de vidrio. Se encontró que no hubo diferencia estadística significativa en el análisis de la RER entre las cepas VNPNU-01 y AADM-01 (p > .05), pero sí con la cepa VNPNU-02 (p < .05). Se obtuvieron basidiomas de V. bombycina en los seis sustratos evaluados, siendo la cepa AADM-01 la más productiva. De acuerdo con este estudio, las tres cepas guatemaltecas de V. bombycina pueden ser utilizadas en la producción de basidiomas en desechos agrícolas, lo que permitiría obtener un alimento nutritivo y generar ingresos a quienes deseen cultivar este hongo.

Volvariella bombycina is a species of edible saprophyte fungus that grows on logs of dead trees and about which there is information about its taste and nutritional and medicinal properties. In Guatemala this species is consumed in several warm regions of the country, but there is still no study on its cultivation locally. The present investigation was carried out in order to know the behavior of three Guatemalan strains of V. bombycina when cultivated in agricultural wastes. The strains were isolated from basidiomata collected in forests close to Guatemala City, using PDA medium and a temperature of 30ºC for incubation. In the inoculum production, the radial extension rate (RER) was calculated using sorghum and wheat grains in Petri dishes. For obtaining basidiomata, six agricultural wastes substrates were analyzed: grazing grass, cane and corn cob, stubble of bean, wheat straw, rice straw and tonché trunk (Ipomoea murucoides), in glass jars. There was found no significant difference in the statistical analysis of the RER with the VNPNU-01 and AADM-01 strains (p > .05), but it was significant with the VNPNU-02 strain (p > .05). Basidiomata of V. bombycina were obtained in the six substrates evaluated, being the AADM-01 strain the most productive. According to this evaluation, the three Guatemalan strains of V. bombycina can be used in the production of basidiomas using agricultural wastes, what would allow the production of a nutritious food and generate another income for those who want to grow this mushroom.

Codon usage bias in the straw mushroom Volvariella volvacea / 生物工程学报

We analyzed the whole genome coding sequence of Volvariella volvacea to study the pattern utilization of codons by Codon W 1.4.2. As results, 24 optimal codons were identified. Moreover, the frequency of codons usage was calculated by CUSP program. We compared the frequency of codons usage of V. volvacea with other organisms including 6 modal value species (Homo sapiens, Saccharomys cerevisiae, Arabidopsis thalian, Mus musculus, Danio rerio and Drosophila melanogaster) and 4 edible fungi (Coprinopsis cinerea, Agaricus bisporus, Lentinula edodes and Pleurotus ostreatus). We found that there were less differences in 3 edible fungi (excluding Pleurotus ostreatus) than 6 modal value species, comparing with the frequency of codons usage of V. volvacea. With software SPSS16.0, cluster analysis which showed differences in the size of codon bias, reflects the evolutionary relationships between species, which can be used as a reference of evolutionary relationships of species. This was the first time for analysis the codon preference among the whole coding sequences of edible fungi, serving as theoretical basis to apply genetic engineering of V. volvacea.

Purification and characterization of phytase with a wide pH adaptation from common edible mushroom Volvariella volvacea (Straw mushroom).

A novel phytase with a molecular mass of 14 kDa was isolated from fresh fruiting bodies of the common edible mushroom Volvariella volvacea (Straw mushroom). The isolation procedure involved successive chromatography on DEAE-cellulose, CM-cellulose, Affi-gel blue gel, Q-Sepharose and Superdex-75. The enzyme was a monomeric protein and was unadsorbed on DEAE-cellulose, CM-cellulose and Affi-gel blue gel, but was adsorbed on Q-Sepharose. The enzyme was purified 51.6-fold from the crude extract with 25.9% yield. Its N-terminal amino acid sequence GEDNEHDTQA exhibited low homology to the other reported phytases. The optimal pH and temperature of the purified enzyme was 5 and 45oC, respectively. The enzyme was quite stable over the pH range of 3.0 to 9.0 with less than 30% change in its activity, suggesting that it can be used in a very wide pH range. The enzyme exhibited broad substrate selectivity towards various phosphorylated compounds, but lacked antifungal activity against tested plant pathogens.

New Species of Agaricales

Clitocybe alboinfundibulliforme sp. nov. is widely distributed in Korea. Volvariella koreana sp. nov. is rarely distributed in Korea. These taxa were occasionally found together at the same place. Both of these species seem to be associated with each other. These two species are fully described and illustrated in this paper.

High-level production of neutral endoglucanase 1 in Pichia pastoris / 生物工程学报

The gene (eg1) encoding for novel endoglucanase 1 was cloned previously from Chinese straw mushroom Volvariella volvacea. EG1 has high thermal stability and optimal pH at neutral and shows great potential in textile and paper industry applications. To improve the expression level of EG1 in Pichia pastoris, the increasing copy number of clone, and its high cell density fermentation in 3.2L fermenter for its high-level expression were investigated in this work. By electro-transformation of pPICZalphaB-egl into GS115EG11 integrated with single copy of eg1 gene, A resistant transformant with 3.8 times higher level expression than GS115EG11 was screened from YPDSZ plate containing 2000 microg/mL of Zeocin. The effect of initial cell density, pH and methanol on its expression and biomass accumulation was evaluated in shaking culture. Optimal EG1 production was observed when initial cell density OD600 was 5.0. EG1 production and biomass accumulation did not seem to vary when cells were induced at different pH values. Both of EG1 and cell density were found to increase with higher methanol concentrations, reaching 62.48 IU/mL and 31.7 (OD600) respectively after 120 h induction with 2.0% (V/V) methanol compared to 30.24 IU/mL and 17.79 (OD60) with 0.25% methanol induction. EG1 expression was further increased by 6.4 times higher than shaking culture after 95.5 hours induction with methanol in fed-batch fermentation, so totally 34 times higher than that for GS115EG11 was achieved by screening of high Zeocin resistant clone and high cell density fermentation. The production of EG1 with 543.36IU/mL CMC activity and 8.80mg/mL protein expression was obtained in Pichia pastoris.

Taxonomic Study on Volvariella in Korea

Diversities of Korean species belonging to the genus Volvariella have been studied through forty five dried specimens collected throughout the Korean peninsula for 28 years, from 1972 to 2000, and preserved in NIAST's herbarium. We have found one unrecorded species of the genus Volvariella in Korea: V. villosavolva (Lloyd) Sing, Stirp Taylori Korean common names were designated. Ten species of the genus Volvariella including the recorded Korean species of Volvariella have been identified and the keys to the species were constructed.