中国栽培糙皮侧耳品种体细胞不亲和性实验与RAPD分析结果的比较

对收集的糙皮侧耳Pleurotus ostreatus19个栽培菌株在贫营养的半PDA培养基中配对进行拮抗线实验,考察其相互间体细胞不亲和性。结果表明,此19个菌株间出现拮抗线的比率是100%,形成的拮抗线类型可分为菌丝集结型(A型)、隔离带型(B型)和暗线型(D型)三类,出现的比例分别是24.9%、23.7%和51.4%。显微观察暗线型拮抗线区域有菌丝自融形成的溶菌沟,另2种拮抗线中没有菌丝自溶。以拮抗线类型分别作为变量进行NTSYS-PC聚类分析,从相似性系数0.48处截断可将其分为3大类,第一类包括802和黑平王等9个菌株;第二类包括苏引6号和江都71等6个菌株;第三类包括夏王40和早秋高丰等4个菌株。应用13条随机引物扩增此19株糙皮侧耳菌株总DNA,共扩增出917条不同分子量的DNA条带。RAPD聚类分析表明,这些菌株的遗传相似性高达85%以上。从相似性系数0.86处截断,也可将这些菌株分为3大类,第一类包括了802和黑平王等17个菌株;第二类仅包括推广一号和夏王40两个菌株;第三类只有831一个菌株。两种方法的聚类分析结果没有相关性。因此,拮抗反应可以作为评价糙皮侧耳栽培菌株之间遗传多样性的方法之一,但与基因组DNA指纹多样性分析结果并不完全吻合,更不能代替分子指纹分析。     

A cytolytic protein from the edible mushroom, Pleurotus ostreatus

Aqueous extracts of the edible mushroom, Pleurotus ostreatus, contain a substance that is lytic in vitro for mammalian erythrocytes. The hemolytic agent, pleurotolysin, was purified to homogeneity and found to be a protein lacking seven of the amino acids commonly found in proteins. In the presence of sodium dodecyl sulfate it exists a monomers of molecular weight 12 050 whereas under non-dissociating conditions it appears to exist as dimers. It is isoelectric at about pH 6.4. The sensitivity of erythrocytes from different animals correlates with sphingomyelin content of the erythrocyte membranes. Sheep erythrocyte membranes inhibit pleurotolysin-induced hemolysis and the inhibition is time and temperature dependent. Ability of membranes to inhibit hemolysis is abolished by prior treatment of membranes with specific phospholipases. Pleurotolysin-induced hemolysis is inhibited by liposomes prepared from cholesterol, dicetyl phosphate and sphingomyelin derived from sheep erythrocytes whereas a variety of other lipid preparations fail to inhibit. It is concluded that sphingomyelin plays a key role in the hemolytic reaction.     

Transformation of the edible mushroom Pleurotus ostreatus by particle bombardment

Uracil auxotroph of Pleurotus ostreatus was transformed to prototrophy by means of particle bombardment. Five transformants were obtained under three conditions differing in the two parameters of target distance and helium pressure. The transformation frequency was one transformant per microg of DNA. In the transformants, plasmid DNAs were integrated into the genomic DNA and stably maintained. This is the first report on transformation of P. ostreatus by particle bombardment.     

Veratryl alcohol stimulates fruiting body formation in the oyster mushroom, Pleurotus ostreatus

The oyster mushroom, Pleurotus ostreatus, cultivated in solid state on sugarcane bagasse-wheat bran (5:1) medium in the presence of veratryl alcohol resulted in an increased production of the fruiting body at earlier times compared to when the fungus was grown in the absence of veratryl alcohol. The results indicate a new physiological role for veratryl alcohol in stimulating fruiting body formation. Veratryl alcohol also stimulated laccase production during the mycelial growth stage. Evidence is also presented that laccases were involved in the physiological development of the fruiting body.     

Biological efficiency and nutritional value of Pleurotus ostreatus cultivated on spent beer grain

Unpretreated spent beer grains were successfully used as a basic substrate material for the cultivation of Pleurotus ostreatus. The effects of spent grain types, additives, substrate moisture content, and substrate packing density on the yield and nutrition of fruit bodies were investigated. The cultivation results showed that few fruit bodies were formed on spent grain alone; however, a significantly high biological efficiency (19.1%) was obtained with the addition of wheat bran to (45%). The chemical analysis of fruit bodies indicated that P. ostreatus cultivated on spent grain substrate had a higher nutritional value than those grown on other reported types of substrates. The total amino acid content in the fruit bodies was 347.5 mg/g dry matter, and the crude protein content was as high as 53.3% on a dry weight basis. It was also found that the cultivation of P. ostreatus increased the crude protein content, while it decreased the ratio of lignin to cellulose, of the spent grain substrate.     

Exopolysaccharide-peptide complex from oyster mushroom (Pleurotus ostreatus) protects against hepatotoxicity in rats

Liver damage involves oxidative stress and a progression from chronic hepatitis to hepatocellular carcinoma (HCC). The increased incidence of liver disease in Egypt and other countries in the last decade, coupled with poor prognosis, justify the critical need to introduce alternative chemopreventive agents that may protect against liver damage. The aim of this study was to evaluate the efficacy of exopolysaccharide-peptide (PSP) complex extracted from Pleurotus ostreatus as a hepatoprotective agent against diethylnitrosamine (DEN)/carbon tetrachloride (CCL₄)-induced hepatocellular damage in rats. The levels of liver injury markers (ALT, AST and ALP) were substantially increased following DEN/CCl₄ treatment. DEN/CCl₄ - induced oxidative stress was confirmed by elevated levels of lipid peroxidation and decreased levels of superoxide dismutase, glutathione-S-transferase, and reduced glutathione. PSP reversed these alterations in the liver and serum, and provided protection evidenced by reversal of histopathological changes in the liver. The present study demonstrated that PSP extract from P. ostreatus exhibited hepatoprotective and antioxidant effects against DEN/CCl₄-induced hepatocellular damage in rats. Given the high prevalence of HCV-related liver damage in Egypt, our results suggest further clinical evaluation of P. ostreatus extracts and their potential hepatoprotective effects in patients with liver disease.     

The mitochondrial genome of the Basidiomycete fungus Pleurotus ostreatus (oyster mushroom)

In this study, the full mitochondrial genome of a basidiomycete fungus, Pleurotus ostreatus, was sequenced and analyzed. It is a circular DNA molecule of 73 242 bp and contains 44 known genes encoding 18 proteins and 26 RNA genes. The protein-coding genes include 14 common mitochondrial genes, one ribosomal small subunit protein 3 gene, one RNA polymerase gene and two DNA polymerase genes. In addition, one RNA and one DNA polymerase genes were identified in a mitochondrial plasmid. These two genes show relatively low similarities to their homologs in the mitochondrial genome but they are nearly identical to the known mitochondrial plasmid genes from another Pleurotus ostreatus strain. This suggests that the plasmid may mediate the horizontal gene transfer of the DNA and RNA polymerase genes into mitochondrial genome, and such a transfer may be an ancient event. Phylogenetic analysis based on the cox1 ORFs verified the traditional classification of Pleurotus ostreatus among fungi. However, the discordances were observed in the phylogenetic trees based on the six cox1 intronic ORFs of Pleurotus ostreatus and their homologs in other species, suggesting that these intronic ORFs are foreign DNA sequences obtained through HGT. In summary, this analysis provides valuable information towards the understanding of the evolution of fungal mtDNA.     

A lectin from an edible mushroom Pleurotus ostreatus as a food intake-suppressing substance

In an experiment in which rats were allowed free access to food and water, the rats did not eat the diet containing a mushroom Pleurotus ostreatus even if they were emaciated. A P. ostreatus lectin (POL) was isolated from the mushroom as the food intake-suppression principle. In hemagglutination inhibition assays, Me-alphaGalNAc was the most potent inhibitor among the monosaccharides tested. Among all the sugars tested, 2'-fucosyllactose (Fucalpha1-->2Galbeta1-->4Glc) was the strongest inhibitor and its inhibitory potency was five times greater than that of Me-alphaGalNAc. POL exhibited a binding ability to bovine submaxillary mucin (BSM) and asialo-BSM and the other glycoproteins were inert to the binding. The food intake-suppressing activity of POL was dependent on the dose. The diet containing 0.1% POL caused a 50% decrease in the food intake of rats against the control.     

Cultivation of the oyster mushroom (Pleurotus ostreatus) on wood substrates in Hawaii

Summary Five non-native, aggressively growing trees, Falcataria moluccana (Miquel) Barneby & Grimes, Casuarina equisetifolia L. ex J. R. & G. Forst, Eucalyptus grandis Hill ex Maid, Psidium cattleianum Sabine, and Trema orientalis (L.) Blume, were evaluated for suitability as substrate for outdoor cultivation of the oyster mushroom, Pleurotus ostreatus (Jacq.: Fr.) Kumm., in Hawaii. An existing shade house was modified for mushroom production and proved to be an adequate fruiting site. Nitrogen-fixing trees (C. equisetifolia, T. orientalis, and F. moluccana) supported greater yield (275.5, 272.4 and 268.8 g/bag, respectively), biological efficiency (70.1, 78.5, and 74.0%, respectively), and flush number (3.0, 3.2, and 3.5) than non-fixers. P. cattleianum supported significantly lower yield (190.5 g/bag) and biological efficiency (44.2%). Mean crop period was 51 days and was not affected by the wood substrate. Similarly, substrate did not have a significant impact on the concentration of nutrients or moisture in fruit bodies. Taste preferences were noted in mushrooms grown on different substrates; those grown on C. equisetifolia were most flavourful and preferred in one taste test.     

137Cs distribution and accumulation in the tissues of cultivated fungi (Pleurotus ostreatus)

The authors examined 137Cs accumulation and distribution in different structures and tissues of Pleurotus ostreatus cultivated under laboratory conditions. The fungi were shown to concentrate 137Cs. A higher concentrations of the radionuclides in the fungi compared to their substrate is manifested at the first stages of the fruit body formation, the maximum content of 137Cs is accumulated by fungi in the middle of bearing stage. The fungus tissues are different by their accumulative capacity as follows (ascending range): central, more dense part of the stipe < stipe < mycelium < cap < generative tissues. 137Cs accumulation in the fruit bodies depends also on the fungus size and age.     

Cloning and developmental expression of a metzincin family metalloprotease cDNA from oyster mushroom Pleurotus ostreatus

A cDNA clone, PoMTP, encoding a putative metzincin family metalloprotease was isolated from the expressed sequence tags of a basidiomycete Pleurotus ostreatus. The 5'-end sequence of PoMTP was determined by the 5'-RACE method. Full-length cDNA sequence (1140 bp) of PoMTP contained a 870 bp open reading frame encoding a protein product of 290 amino acids in addition to a 99 bp of 5'-untranslated sequence and a 171 bp of 3'-untranslated sequence with a poly(A) tail. The deduced amino-acid sequences of PoMTP contained an extensive zinc-binding consensus sequence and a so-called Met-turn sequence which are typical for the metzincin family of metalloproteases, indicating that the PoMTP protein belongs to the metzincin metalloproteases. Four cysteine residues were also observed in the zinc-binding region of PoMTP amino-acid sequence, which are known to be important for the structure and the function of some subfamilies of the metzincins. Comparison of the PoMTP in sequence database showed no significant homology with functionally known metalloproteases of Armillaria mellea, Grifola frondosa, Lentinula edodes, Pleurotus ostreatus, Schizophyllum commune and Tricholoma saponaceum in mushroom. Northern blot and qunatitative RT-PCR analyses indicated the PoMTP mRNA to be abundant at primordial and fruit body stages, but scarce at the mycelial stage, suggesting that the PoMTP metalloprotease plays an important role in mushroom fruiting.     

Bioremediation of hexachlorocyclohexane (HCH) in soil using spent mushroom compost of Pleurotus ostreatus

Abstract

Hexachlorocyclohexane (HCH), a highly chlorinated pesticide, was used worldwide in the 1950s and 1960s. HCH toxic residues are still detected in environmental compartments. Thus, effective, viable and eco-friendly strategy is required for its remediation. In this study, degradation of four HCH isomers was evaluated by amending contaminated soil using four treatments of spent mushroom compost (SMC) of Pleurotus ostraetus. The soil was incubated for 5 weeks and was sampled every seven days. Quantitative attenuation in HCH was calculated using gas chromatography–electron capture detector (GC-ECD) and metabolite was identified using gas chromatography–mass selective detector (GC-MSD). Maximum reduction 58%, 26%, 45%, and 64% for α-, β-, γ- and δ-HCH isomers, respectively, using SMC and soil (both unsterilized) showed that this treatment was the best for bioremediation of HCH in soil. However, when one of the factors, either soil or SMC, was sterilized, a significant reduction in HCH degradation was noticed. The second most reduction of isomers was seen during treatment where unsterilized SMC was added in sterilized soil followed by treatment where SMC was sterilized but soil was not. Abiotic control did not remove any significant quantities of HCH. Simple first-order (SFO) kinetic confirmed that SMC reduced the half-live manifolds as compared to biotic control. Only one metabolite δ-PCCH was identified during the course of study.     

Heat treatment of wheat straw by immersion in hot water decreases mushroom yield in Pleurotus ostreatus

BackgroundThe oyster mushroom, Pleurotus ostreatus, is cultivated worldwide. It is one of the most appreciated mushrooms due to its high nutritional value. Immersion of the substrate in hot water is one of the most popular and worldwide treatment used for mushroom farmers. It is cheap and easy to implement.AimsTo compare the yields obtained during mushroom production of P. ostreatus using different pre-treatments (immersion in hot water, sterilization by steam and the use of fungicide) to determine if they influence mushroom crop.MethodsFour different treatments of substrate (wheat straw) were carried out: (i) immersion in hot water (IHW); (ii) steam sterilization; (iii) chemical; and (iv) untreated. The residual water from the IHW treatment was used to evaluate the mycelium growth and the production of P. ostreatus.ResultsCarbendazim treatment produced highest yields (BE: 106.93%) while IHW produced the lowest BE with 75.83%. Sugars, N, P, K and Ca were found in residual water of IHW treatment. The residual water increased the mycelium growth but did not increase yields.ConclusionsWe have proved that IHW treatment of substrate reduced yields at least 20% when compared with other straw treatments such as steam, chemical or untreated wheat straw. Nutrients like sugars, proteins and minerals were found in the residual water extract which is the resultant water where the immersion treatment is carried out. The loss of these nutrients would be the cause of yield decrease. Alternative methods to the use of IHW as treatment of the substrate should be considered to reduce economical loss.     

Cultivation of oyster mushroom Pleurotus ostreatus on date-palm leaves mixed with other agro-wastes in Saudi Arabia

Promoting the use of agricultural waste is one of the newly prepared water and environment friendly agriculture strategies in the Kingdom of Saudi Arabia (KSA). The objective of this research was to study the efficiency of cultivating oyster mushroom (Pleurotus ostreatus) on date palm wastes mixed with other agricultural wastes available in KSA. Four agricultural wastes were mixed with date palm leaves at different ratios, with two supplements and three spawn rates were used. Wheat straw mixed with date palm at ratio of 25 (date palm): 75 (agro-waste) showed the best results in most of the parameters measured. Corn meal was superior over wheat bran as a supplement in all treatments. Parameter values increased with the increase of the spawn rate of P. ostreatus. Treatments with date palm leave wastes contained higher carbohydrates and fibers. No significant differences were found among the fruiting bodies produced on the different agro-wastes studied for the different proximates analyzed. Analyses of metal concentration showed that potassium was the highest in all the treatments tested followed by Na, Mg, Ca, and Zn. This is the first study that reported the success of growing oyster mushroom on date palm leaf wastes mixed with other agro-wastes obtainable in KSA.     

Molecular identification of Trichoderma species associated with Pleurotus ostreatus and natural substrates of the oyster mushroom

Green mold of Pleurotus ostreatus , caused by Trichoderma species, has recently resulted in crop losses worldwide. Therefore, there is an emerging need for rapid means of diagnosing the causal agents. A PCR assay was developed for rapid detection of Trichoderma pleurotum and Trichoderma pleuroticola , the two pathogens causing green mold of P. ostreatus . Three oligonucleotide primers were designed for identifying these species in a multiplex PCR assay based on DNA sequences within the fourth and fifth introns in the translation elongation factor 1α gene. The primers detected the presence of T. pleurotum and/or T. pleuroticola directly in the growing substrates of oyster mushrooms, without the need for isolating the pathogens. The assay was used to assess the presence of the two species in natural environments in which P. ostreatus can be found in Hungary, and demonstrated that T. pleuroticola was present in the growing substrates and on the surface of the basidiomes of wild oyster mushrooms. Other Trichoderma species detected in these substrates and habitats were Trichoderma harzianum, Trichoderma longibrachiatum and Trichoderma atroviride. Trichoderma pleurotum was not found in any of the samples from the forested areas tested in this study.     

不同原料栽培平菇的生态学转化特点研究

运用熟料袋栽方法对小麦杆和棉籽壳栽培平菇的转化特点进行了研究．结果表明平菇生产转化率（Ｒｃ）无显著差异,剩余率（Ｒｒ）和耗出率（Ｒｄ）有极显著差异,Ｒｃ、Ｒｒ和Ｒｄ相互间有极显著的直线回归关系．不同处理中Ｒｄ对Ｒｃ的回归系数（ｂ）一致,但回归截距（ａ）有较大差异,Ｒｄ对Ｒｒ的回归系数（ｂ）和截距（ａ）都有显著差异,但ｂ与ａ之比却十分接近．说明平菇生产中对原料的消耗可分为两个部分,一是基础消耗,与平菇产量无关,二是生产直接消耗,与平菇的产出率呈正相关．     

A new lectin with highly potent antihepatoma and antisarcoma activities from the oyster mushroom Pleurotus ostreatus

A dimeric lectin, composed of subunits with a molecular weight of 40 and 41 kDa, respectively, and demonstrating similarity in N-terminal sequence to each other and to Aleuria aurantia lectin, was isolated from fresh fruiting bodies of the edible mushroom Pleurotus ostreatus. The lectin was unadsorbed on DEAE-cellulose in 10 mmol/L phosphate buffer (pH 7.5), subsequently adsorbed on CM-cellulose in 10 mmol/L NH(4)OAc (pH 5.4), and came off in the first peak from a Superose 12 column during fast protein liquid chromatography. The lectin was acid-labile, alkali-labile, and heat-labile. Its hemagglutinating activity was sensitive to inhibition by CaCl(2), MgCl(2), MnCL(2) and FeCl(3) and potentiation by AlCl(3). Melibiose, lactose, d-galactose, alpha-methyl-d-galactopyranoside, N-acetylneuraminic acid, raffinose, and inulin were capable of inhibiting its hemagglutinating activity, with melibiose being the most potent. The lectin exerted potent antitumor activity in mice bearing sarcoma S-180 and hepatoma H-22. Survival in these mice was prolonged and body weight increase reduced after lectin treatment.