Hemagglutinating activity of the fungusLentinus edodes (Berk.) sing [Lentinus edodes (Berk.) Pegler]

The hemagglutinating (HA) activity of the submerged mycelium and the culture liquid (CL) of four strains ofLentinus edodes was studied. The HA activity of the CLs proved to be much higher than that of mycelia. The carbohydrate specificity of fungal agglutinating factors was determined. HA activity was investigated as a function of the inoculum size, cultivation temperature, and culture age. The agglutinating activity of different morphogenetic structures ofL. edodes F-249, including mycelium, brown mycelial mat (MM), primordia, and fruiting bodies, was studied. MM was found to possess the maximum HA activity, which can be explained by the possible involvement of agglutinins in the formation of MM, which is composed of glued hyphae.     

Hemagglutinating activity of Lentinus edodes (Berk.) Sing [Lentinula edodes (Berk.) Pegler]

The hemagglutinating (HA) activity of the submerged mycelium and the culture liquid (CL) of four strains of Lentinus edodes was studied. The HA activity of CLs proved to be much higher than that of mycelia. The carbohydrate specificity of fungal agglutinating factors was determined. HA activity was investigated as a function of the inoculum size, cultivation temperature, and culture age. The agglutinating activity of different morphogenetic structures of L. edodes F-249, including mycelium, brown mycelial mat (MM), primordia, and fruiting bodies, was studied, MM was found to possess the maximum HA activity, which can be explained by the possible involvement of agglutinins in the formation of MM, which is composed of glued hyphae.     

Characterization of an extracellular glycolipid from Lentinus edodes (Berk.) Sing [Lentinula edodes (Berk.) Pegler]

Submerged mycelium of a xylotrophic basidiomycete Lentinus edodes produces an extracellular glycolipid, S3, associated with a lectin. Galactose glycan residue, as well as the lipid pool composition, which includes nonhydroxylated short-chain fatty acids, is uncommon for basidiomycetes. The glycolipid consists of D-galactopyranose (15% of S3 contains galactose sulfate) acylated by octadecanoic and nonadecanoic fatty acid residues (28 and 72%, respectively). The glycolipid structure and composition are confirmed by physicochemical analysis. The glycolipid is assumed to be a regulator of lectin activity.     

一种含有单链RNA的香菇球状病毒

从生长不正常的香菇(Lentinus edodes(Berk.)Sing)菌株中分离到一种等轴对称含单链RNA的病毒颗粒。病毒颗粒在电镜下直径为33～34nm,在SDS-聚丙烯酰胺凝胶电泳中病毒外壳蛋白分子量为22000道尔顿。病毒核酸径DNase1和SI酶解试验及热变性紫外吸收曲线试验证明为单链RNA,在1.5％的琼脂糖凝胶电泳中,病毒核酸呈现一条带,分子量为2.38×10~6道尔顿。     

Relationship between the molecular structure of nitrogen source and the activity of the extracellular lectins of Lentinus edodes (Berk.) Sing [Lentinula edodes (Berk.) Pegler] upon submerged cultivation

The activity of the extracellular lectins of Lentinus edodes (Berk.) Sing [Lentinula edodes (Berk.) Pegler] and the formation of a pigmented mycelial film by this fungus upon submerged cultivation in a synthetic medium were found to depend on the presence of some amino acids (particularly, asparagine) and Ca2+ and Mn2+ ions in the medium. Quantum chemical calculations suggest that the different character of the interaction of amino acids with the aforementioned ions is due to differences in the hydrophobicity of the amino acids rather than to differences in the electron structure of the amino acid zwitterions.     

Relationship between the Molecular Structure of the Nitrogen Source and the Activity of the Extracellular Lectins of Lentinus edodes (Berk.) Sing [Lentinula edodes (Berk.) Pegler] upon Submerged Cultivation

The activity of the extracellular lectins of Lentinus edodes (Berk.) Sing [Lentinula edodes (Berk.) Pegler] and the formation of a pigmented mycelial film by this fungus upon submerged cultivation in a synthetic medium were found to depend on the presence of some amino acids (particularly, asparagine) and Ca²⁺ and Mn²⁺ ions in the medium. Quantum-chemical calculations suggest that the different character of the interaction of amino acids with the aforementioned ions is due to differences in the hydrophobicity of the amino acids rather than to differences in the electron structure of the amino acid zwitterions.     

The detection of single-stranded RNA in an isometric virus-like particle from Shiitake mushroom [Lentinus edodes (Berk.) Sing.]

Isometric virus-like particles (VLPs) with diameter of approximately 34 nm containing ss-RNA were purified from abnormal mycelium of Shiitake mushroom, Lentinus edodes (Berk.) Sing. SDS-polyacrylamide gel elec-trophoresis demonstrated that the virions contain a single capsid polypeptide with molecular weight of about 22 000 daltons. The nucleic acid extract from purified VLPs preparations showed only one band with a size of approximately 7.3 kilobases. The susceptibility to RNase 1 and S1 digestions, resistance to DNase and thermal denaturation behaviour of the viral genome indicated that it is a single-stranded RNA. To our knowledge, isometric single-stranded RNA VLPs isolated from Shiitake mushroom mycelia have not been reported before.     

Fruiting ofLentinus edodes (Shiitake) in liquid media

Summary Eight dikaryotic stocks ofLentinus edodes (Berk.) Sing. were studied in respect to fruiting in several different formulations of chemically-defined liquid media. On the two media which included the same four solutions (minerals, trace elements, vitamins and salicylic acid) the stocks differed only slightly in growth but were markedly different in primordia and fruitingbody formation. Stocks also showed variation in respect to fruiting, following incubation in media from which one of the solutions was omitted, and it was suggested that this was a consequence of differences in genes controlling fruiting. Inorganic substances (glass wool, vermiculite and perlite) served satisfactorily in supporting fruiting bodies in liquid media. Light was essential for borwn-pigment formation of the mycelial coat and for fruiting-body maturation but was not required for formation of primordia.

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Resumen Se estudío la fructificación de ocho cepas dikaríoticas de Lentinus edodes en varias fórmulas químicas diferentes de medio líquido definido. En dos medios que contenían las mismas cuatro soluciones (mineral, elementos trazas, vitaminas y ácidos salicílico) las diferencias en crecimiento entre las cepas eran apenas perceptibles pero eran marcadamente diferentes en relación a la formación del primordio y del cuerpo fructífero. Las cepas también mostraban variación en la fructificatión cuando se incubaban en un medio al cual una de las soluciones se le omitía, sugiriéndose ésto como una consecuencia de diferencias en los genes controlando la fructificación. Sustancias inorgánicas (lana de vidrio, vermiculita y perlita) fueron usadas satisfactoriamente como soporte de los cuerpos fructíferos en medio líquido. La luz era esencial para la formación del pigmento marrón de la capa micelial y para la maduración del cuerpo fructífero, pero no era requerida para la formación de primordio. Received 1 November 1986; accepted 29 December 1986

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Résumé Huit souches dicaryotes deLentinus edodes (Berk.) ont été étudiées en ce qui concerne la fruitification dans différentes formulations de milieux liquides chimiquement définis. Sur les deux milieux contentant les quatre mêmes solutions (composés minéraux, oligo-éléments, vitamines et acide salicylique), les souches différent peu en ce qui concerne la croissance, mais par contre foretement en ce qui concerne la formation de primordia et de fructifications. La fructification des souches varie aussi lorsque l'incubation est effectuée dans des milieux où l'une gènes contrôlant la frucitification. Certaines substances minérales (laine de verre, vermiculite et perlite) soutiennent efficacement les fructifications en mlieu liquide. La lumière est nécessaire à la pigmentation brune du mycélium et à la maturation des fructifications, mais n'influe pas sur la production de primordia.

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Visiting Professor in the Department of Biology, CUHK, from the State University of New York at Buffalo, USA.     

A straight correlation between mutagenic activity and beta-galactosidase activity induced by monofunctional alkylating agents.

Eight monofunctional alkylating agents were examined for their ability to induce mutation in Salmonella typhimurium. The assay was carried out in S. typhimurium TA100 with the preincubation method. The SN1-type agents were more mutagenic than the SN2-type ones; besides, methylating agents exerted more mutagenic activity than ethylating ones. Those responses in the reversion assay were quite similar to the results obtained previously with the beta-galactosidase assay in Escherichia coli CSH26/pMCP1000 (alkA'-lacZ') as to the induction of the adaptive response. A good correlation was found between mutagenic potency in the reverse mutation assay and inducing potency in the beta-galactosidase assay.     

The elimination of mutagenic lesions induced by alkylating agents and UV in V79 Chinese hamster cells

The mutagenicity of MNU, EMS, BMS and UV light was compared by analyzing the dose-response curve just before and after the replicative process of the HGPRT gene in synchronized V79 Chinese hamster cells. This system makes it possible to compare a 10-h period for repair of different mutagenic lesions with no time for repair. Additional time for repair in synchronized V79 cells resulted in a reduced response for MNU and UV, but not for EMS and BMS. This result suggests that an error-free repair process operates on mutagenic lesions in methylated DNA and on thymine dimers, but not on ethylated and butylated DNA. Based on these results, it is concluded that the repair capacity of V79 cells to remove mutagenic lesions is characterized as low for UV, moderate for MNU and not detectable for the mutagenic lesions induced by EMS and BMS.     

Nucleotide pools and mutagenic effects of alkylating agents in wild-type and APRT-deficient Friend erythroleukaemia cells

Wild-type Friend mouse erythroleukaemia cells (clone 707) were compared with adenine phosphoribosyltransferase (APRT)-deficient mutant subclones (707DAP8 and 707DAP10) for sensitivity to cell killing and mutagenesis by ethyl methanesulphonate (EMS) and methyl methanesulphonate (MMS). Cells were exposed to 0-300 micrograms/ml EMS and to 0-20 micrograms/ml MMS for a period of 16 h. A slight difference was found between wild-type cells and the two APRT-deficient subclones in terms of sensitivity to cell killing by both mutagens. The APRT-deficient subclones were, however, significantly more sensitive than wild-type cells to mutagenesis to 5-bromo-2-deoxyuridine resistance and 6-thioguanine resistance by EMS and MMS. The APRT-deficient subclones were found to have significantly decreased levels of dATP and dTTP nucleotides and decreased levels of all four ribonucleoside triphosphates (ATP, GTP, CTP and UTP) relative to wild-type cells. Wild-type Friend cells were found to have insignificant levels O6-methylguanine-DNA methyl transferase and it is suggested that the increased mutagen sensitivity of APRT-deficient cells may be due to imbalance of deoxyribonucleoside triphosphate pools during DNA excision-repair processes, or more probably due to deficiency of ATP for ATP-dependent DNA excision-repair enzymes.     

鲜切香菇贮藏过程中质构变化与自溶自噬分析

旨在明确鲜切香菇经过机械损伤后发生的应激生理以及自溶进程中细胞质构的变化。以香菇0912子实体新鲜切片为材料,研究低温和室温贮藏条件下香菇切片生理生化指标的变化趋势,利用显微技术研究老化组织中细胞结构的变化。结果显示低温贮藏条件有利于减缓鲜切香菇褐变、软化、蒸腾失重及抗氧化活性的下降。微观结构研究显示鲜切香菇经过机械损伤后激发了自溶自噬机制,细胞内出现胞壁断裂、胞膜消融、自噬体吞噬细胞器、大量DNA断裂、细胞核消失及细胞解体等现象。鲜切香菇切片在损伤后发生自溶自噬现象,微观组织结构的破坏,是菇体劣变的重要原因之一,在外界贮藏环境的共同作用下加速腐败的进程。     

Alterations in Bacillus subtilis transforming DNA induced by beta-propiolactone and 1,3-propane sultone, two mutagenic and carcinogenic alkylating agents.

Transforming DNA was exposed to either beta-propiolactone or 1,3-propane sultone and then used for transformation of competent bacteria to nutritional independence from tyrosine and tryptophan (linked markers) and leucine (an unlinked marker). The ability to transform was progressively lost by the DNA during incubation with either of these two chemicals. For all three markers the inactivation curve was biphasic, with a short period of rapid inactivation followed by one characterized by a much slower rate. The overall rate of inactivation was different for all three markers and presumably was related to the size of the marker. The decrease in the transforming activity was in part due to the slower rate of penetration of alkylated DNA through the cellular membrane and its inability to enter the recipient bacteria. This decrease in the rate of cellular uptake, even for DNA eventually destined to enter the cell, began almost immediately after its exposure to the chemical and ended up with an almost complete lack of recognition of the heavily alkylated DNA by the specific surface receptors of competent cells. Such DNA attached to sites on the surface of competent bacteria which were different from receptors specific for the untreated nucleic acid. This attachment was not followed by uptake of the altered DNA. Presence of albumin during the incubation with a carcinogen further increased the degree of inactivation, indicating that the artificial nucleoproteins produced under such conditions were less efficient in the transformation assay than was the naked DNA. Cotransfomration of close markers progressively decreased, beginning immediately after the start of incubation of DNA with the chemicals. Extensively alkylated DNA fractionated by sedimentation through sucrose density gradients showed a peculiar distribution of cotransforming activity for such markers; namely, molecules larger than the bulk of DNA ("megamolecules") showed less ability to transform the second marker than did some of the apparently smaller molecules which sedimented more slowly through the gradient. An increase in cotransformation of distant markers was evident in DNA molecules after a short exposure to an alkylating agent, but cotransformation of such markers was absent in DNA treated for longer periods. The observed changes in the transforming and cotransforming activities of the alkylated DNA can be explained by what is known about the physicochemistry of such DNA and in particular about the propensity of the alkylated and broken molecules to form complexes with themselves and with other macromolecules.     

Facilitation by pyrimidine deoxyribonucleosides and hypoxanthine of mutagenic and cytotoxic effects of monofunctional alkylating agents in Chinese hamster cells.

Hypoxanthine (Hx), thymidine (TdR) and deoxycytidine (CdR), at concentrations of 10(-5) M increased the yield of 8-azaguanine-resistant (AzGr) mutants induced by N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) in cultured Chinese hamster V79 cells. The cytotoxicity of MNNG was increased 2-fold in the presence of Hx, and more than 10-fold in the presence of TdR. This cytotoxic effect of TdR was abolished by equal concentrations of CdR, which by itself did not increase the cytotoxicity of MNNG. However, the yield of MNNG-induced AzGr colonies was increased 2--10-fold in the presence of both CdR and TdR. The AzGr colonies displayed phenotypes characteristic of hypoxanthine: guaninephosphoribosyltransferase-deficient (HGPRT-) mutants, or indicative of mutant HGPRT with altered substrate affinities. The nucleosides did not affect the growth or expression time of the HGPRT- mutants; the same extent of alkali-labile DNA damage occurred in cells treated with alkylating agents in the presence and absence of TdR and CdR; and the increase in mutation frequency in the presence of these nucleosides occurred not only with MNNG, but also with ethylating agents. Nucleosides treated with MNNG were not mutagenic, and treatment of the cells with TdR and CdR only prior to treatment with MNNG or only during selection with AzG did not increase the induced mutation frequency. Therefore, the interpretation is proposed that CdR, TdR and Hx produce nucleotide-pool imbalances that increase lethal and mutagenic errors of replication of alkylated DNA.     

Biodegradation of an Organoselenium Compound to Elemental Selenium by Lentinula edodes (Shiitake) Mushroom

The present paper reports for the first time the transformation of an organic selenium compound into red selenium (Se), which causes the intense red pigmentation of Lentinula edodes (shiitake mushroom) mycelia. The biotransformation of 1,5-diphenyl-3-selenopentanedione-1,5 (diacetophenonyl selenide, preparation DAPS-25) was studied in liquid- and solid-phase cultures of L. edodes. In liquid culture medium, a red color develops in the mycelium at initial DAPS-25 concentrations equal to or higher than 0.1?mmol/l. The intensity and initiation time of coloration is Se concentration-dependent. Semiquantitative data obtained by physicochemical methods on the extent of Se and acetophenone production suggest that L. edodes is able to absorb and/or destruct this organic Se xenobiotic.     

Lethal and mutagenic effects of radiation and alkylating agents on two strains of mouse L5178Y cells

In previous studies, the two closely related strains of L5178Y (LY) mouse lymphoma cells, LY-R and LY-S, have been shown to differ in their sensitivity to UV and ionizing radiation. Thus, in comparison to strain LY-R, strain LY-S has been found to be more sensitive to the lethal effects of ionizing radiation, more resistant to the lethal effects of UV radiation, but less mutable at the hypoxanthine-guanine phosphoribosyl transferase (HGPRT) locus by both UV and X-radiation. In the present work, the lethal and mutagenic effects of ethyl methanesulfonate (EMS), methyl nitrosourea (MNU) and UV radiation (254 nm) were compared in the two strains. Mutability at the Na+/K+-ATPase locus as well as the HGPRT locus was determined. As previously reported, we found strain LY-S to be more resistant than strain LY-R to the lethal effects of UV radiation. In contrast, strain LY-S was more sensitive to the cytotoxic effects of the two alkylating agents. In spite of these differences in sensitivity, we found strain LY-S to be less mutable than strain LY-R by all 3 agents at the HGPRT locus. At the Na+/K+-ATPase locus, strain LY-S was also less mutable than strain LY-R by equal concentrations of EMS and UV radiation and by equitoxic concentrations of MNU. However, the difference between the strains was much more pronounced at the HGPRT locus than at the Na+/K+-ATPase locus. We have suggested that the interaction of unrepaired lesions in strain LY-S tends to cause an excess of deletions and multilocus effects, which in turn result in a locus-dependent decrease in the recovery of viable LY-S mutant cells.     

Auxin synthesis by the higher fungus Lentinus edodes (Berk.) Sing in the presence of low concentrations of indole compounds

The auxin formation in a submerged culture of the xylotrophic basidiomycete Lentinus edodes (Berk.) Sing (Lentinula edodes (Berk.) Pegler) (shiitake) is studied. Biologically active substances of an indole nature are identified, "the effect of small doses" of which lies in not only the stimulation of growth of the mycelium (indole-3-acetic acid, 2 x 10(-7)-2 x 10(-4) g/l), but also in the induction of tryptophan-independent paths of auxin biosynthesis. The above-mentioned path is realized in the presence of exogenous indole (1 x 10(-3)-1 x 10(-4) g/l), as well as while inducing the biosynthesis of indole-3-acetic acid by its microadditives (1 x 10(-5)-1 x 10(-8) g/l), and is accompanied by the formation of anthranilic acid (up to 1.5 mg/l). Induction of the generative development stage ofshiitake by indole derivatives is revealed. It was found that among the studied compounds only indoleacetamide at a concentration of an order of x 10(-4) g/l in the culture fluid of L. edodes had a pronounced stimulatory effect on the formation of shiitake's brown mycelial film.     

Rhodium(III) complexes as genotoxic agents: photochemical effects and their implications

The genetic toxicology of coordination compounds of transition metals has been of considerable interest since the application of cis-platinum(II) to the therapy of solid tumors. The nature of reactions of such compounds with DNA is still unclear, despite intensive investigation. In this study, several coordination compounds of rhodium(III) were tested for DNA-damaging activity and mutagenicity in bacterial assays in an attempt to understand both the chemical species involved in interactions with DNA and any structural requirements for such interactions. For several complexes it appears that dissociation of a ligand from the complex precedes reactions with DNA. This conclusion stems from the finding that photosensitive complexes of rhodium(III) are often many times more toxic to repair-deficient bacterial stains of E. coli K12 when incubated in the light than when incubated in the dark. Similar responses were seen for mutagenicity in S. typhimurium strain TA100. However, reversion of strain TA102 was largely independent of light exposure. Comparisons between mutagenicity and DNA-damaging activity revealed that the 3 activities measured sorted with some independence among the different compounds tested. Thus, the profiles for crosslink formation and/or generation of oxidative mutagens (mutagenicity in S. typhimurium strain TA102), mutagenicity in TA100 and DNA-damaging activity for the various groups of complexes showed many of the theoretically possible combinations of response in the assays. It is possible, then, that there are different structural requirements for DNA-damaging activity and mutagenicity respectively. This may indicate that synthesis of coordination compounds with specific genotoxic properties is possible. Such syntheses may provide complexes for study of DNA-metal interactions and could, later, direct an approach to the design of new antitumor agents.