扑草净对远志幼苗根系活力及氧化胁迫的影响

以远志(Polygala tenuifolia Willd.)为材料,应用组织化学和生物化学的方法研究不同浓度扑草净(0—400 mg/L)对远志幼苗生长、根系活力、膜脂过氧化、活性氧含量及抗氧化酶活性等的影响。10 mg/L扑草净对远志幼苗根系活力、细胞膜完整性及活性氧的积累几乎无显著影响,而25—400 mg/L扑草净处理则显著增加活性氧的积累,明显抑制根系活力且破坏细胞膜完整性;上述结果进一步被膜脂过氧化、质膜完整性、活性氧产生(O.2-和H2O2)的非损伤组织化学染色所证明。远志幼苗可通过多种抗氧化酶(SOD、POD、CAT、APX等)和非酶抗氧化剂(如脯氨酸)的相互协调作用,清除低浓度扑草净胁迫诱发产生的活性氧,减轻对细胞的伤害。研究结果表明,发芽期是远志对扑草净处理的敏感时期,较为安全的扑草净临界浓度为10 mg/L;25mg/L扑草净处理即引起远志幼苗氧化胁迫和膜脂过氧化,使细胞膜的完整性受到破坏,根系活力下降,抑制了远志幼苗的生长发育。该研究为远志抗除草剂胁迫机制及其栽培过程中除草剂的安全合理使用提供理论依据。     

Conidium Germination Rate in Wild and Domesticated Yellow-Green Aspergilli

Conidia of domesticated yellow-green aspergilli from strains of Aspergillus oryzae (Ahlburg) Cohn and Aspergillus sojae Sakaguchi and Yamada ex Murakami, used in the preparation of koji inoculum, germinate approximately 3 h sooner than conidia produced by related wild species, Aspergillus flavus Link ex Fr. and Aspergillus parasiticus Speare. There was no consistent relationship between average conidium size and estimated 50% germination time. Germination trials were conducted on Czapek agar at 28°C. A hypothesis is offered that, in the propagation of koji inoculum, selection has favored those individuals capable of rapid conidium germination and germ tube extension, attributes that enable them to gain the available substrate during intraspecific competition.     

Formation of resting body byCephalosporium roseo-griseum Saksena inside the conidiophore ofAspergillus flavus Link. Ex Fries during mycoparasitism

Summary Mycoparasitic behaviour ofCephalosporium roseo-griseum Saksena withAspergillus flavus Link. ex Fries was studiedin vitro. Frequent coiling of hyphae ofC. roseo-griseum around the conidiophores ofA. flavus, penetration of hyphae ofC. roseo-griseum inside those ofA. flavus, and formation of resting bodies byC. roseo-griseum in the conidiophores ofA. flavus were observed.     

Effects of s-triazine herbicides on hormone-receptor complex formation, 5α-reductase and 3α-hydroxysteroid dehydrogenase activity at the anterior pituitary level

Experiments were performed to study the effects of s-triazine herbicides, atrazine¹ and prometryne, on 5α-dihydrotestosterone (5α-DHT) receptor complex formation and on the activity of the 5α-reductase and 3α-hydroxysteroid dehydrogenase system in the anterior pituitary of male rats. By sucrose density gradient separation, it was found that in the presence of 0.4 mmol of atrazine or prometryne, 5α-DHT binding to receptor proteins in pituitary tissue was decreased by 27% and 17%, respectively. In in vitro experiments, the addition of atrazine or prometryne decreases the conversion of testosterone to 5α-DHT and the conversion of 5α-DHT to 5α-androstan-3α,17β-diol (3α-diol) in the anterior pituitary. The concentration in the range of 0.6 to 12 mmol of both herbicides, inhibited the 5α-reductase and 3α-hydroxysteroid dehydrogenase activity from 7–92%. in vivo subcutaneous (s.c.) administration of atrazine and prometryne reduced the 5α-reductase activity in the anterior pituitary. A single dose (0.1 mg/100 g b.w.) of atrazine decreases the amount of the 5α-reduced metabolite by 34%, while the same dose injected twice or a double dose (0.2 mg/100 g b.w.) inhibited by 46%. A single dose of prometryne (0.1 mg/100 g b.w.) does not affect the enzymic activity, while two injections of a single dose or a single injection of a double dose (0.2 mg/100 g b.w.) decreased the 5α-reductase activity by 17%.     

A new secoiridoid and a new xanthone glycoside from the whole plants of Lomatogonium rotatum

A new secoiridoid (1) and a new xanthone glycoside (2), together with fourteen known compounds (3−16) were isolated from the dried whole plants of Lomatogonium rotatum (L.) Fries ex Nym. The chemical structures were elucidated based on extensive spectroscopic experiments, including 1D and 2D NMR as well as HR-ESI-MS, and comparison with those reported in the literature. All the compounds were evaluated for anti-complementary activity against the alternative pathways. Compounds 12 and 16 exhibited anti-complementary activity.     

Cuticular terminology in Russula (agaricales)

The pileus cuticle is one-layered in a few species ofRussula, but in the others it can be interpreted as composed of two layers—the epicutis uppermost and below this, the subcutis. The basic difference between the two layers is in hyphal orientation. Cell inflation may obscure the orientation in the cuticles of some species. This has given rise to differing interpretations of cuticular structure, especially in regard to the number of nameable layers present, and thus to differing terms for the layers. No Russulas illustrate this better than those of subsectionVirescentinae, of which the two most common North American species,R. crustosa Peck andR. virescens (Schaeffer ex Secretan) Fries, are discussed and described.     

Natural occurrence of aflatoxin andAlternaria mycotoxins in oilseed rape from Catalonia (Spain): Incidence of toxigenic strains

During an investigation of the mycoflora on oilseed rape, the predominant fungal species present in 20 samples collected from Catalonia (Spain) wereAlternaria alternata (Fries) Keissler,Penicillium spp. andAspergillus flavus. None of the 20 samples analyzed presented contamination byAlternaria mycotoxins (tenuazonic acid, alternariol, alternariol methyl ether, altertoxin I and altertoxin II). Only aflatoxin B₁ was detected in 1 of the 20 samples analyzed, with a concentration of 0.25 ppb. Of the 40Aspergillus flavus strains isolated from oilseed rape samples, only 3 revealed aflatoxigenic capacity. None of thePenicillium spp. isolated from oilseed rape samples revealed mycotoxigenic capacity (citreoviridin, griseofulvin, citrinin, patulin and penicillic acid).     

Mycological contamination of Ogiri (fermented sesame seeds) during production in Sierra Leone

Ogiri (fermented sesame seeds) was prepared in the laboratory and at home by selected participants. No fungal participation was observed during the normal fermentation process. However, fungal contamination was observed when improper handling techniques were employed. Out of the 49 samples examined, 41 fungal isolates were made. Aspergillus spp were the dominant group irrespective of the locality. Toxigenic Aspergillus included A. flavus Link ex Fries, A. tamarii Kita and A. ochraceus Wilhelm. P. citrinum Thom was the only toxigenic Penicillium isolated. The role of the different types of wraps used for the fermentation, marketing and storage of the product was also determined.     

The 16S rRNA and mcrA gene based comparative diversity of methanogens in cattle fed on high fibre based diet

In the present study, the diversity of rumen methanogens in crossbred Karan Fries cattle was determined by constructing 16S rRNA and mcrA (methyl coenzyme-M reductase α subunit) gene libraries using specific primers. All thirteen OTUs or phylotypes from 16S rRNA library clustered with order Methanobacteriales, twelve of which aligned with Methanobrevibacter spp., whereas one OTU resemble with Methanosphaera stadtmanae. Out of eighteen OTUs identified from mcrA gene library, fifteen clustered with order Methanobacteriales, two resemble with Methanomicrobiales and remaining one grouped with Methanosarcinales. These results revealed that Methanobrevibacter phylotype was predominantly present in Karan Fries crossbred cattle fed on high fibrous diet containing wheat straw. Compared to 16S rRNA gene, mcrA gene OTUs clustered in three orders providing better insights of rumen methanogens diversity in cattle.     

Mycoremediation of crude oil contaminated soil by specific fungi isolated from Dhahran in Saudi Arabia

Crude oil biodegrading microorganism considers the key role for environmental preserving. In this investigation, crude oil biodegrading fungal strains have been isolated in polluted soil of crude-oil at khurais oil ground in Kingdom of Saudi Arabia. Among of 22 fungal isolates, only three isolates reflected potential capability for oil degradation. These isolates were identified and submitted to GenBank as (A1) Aspergillus polyporicola (MT448790), (A2) Aspergillus spelaeus (MT448791) and (A3) Aspergillus niger (MT459302) through internal-transcribed spacer-regions (ITS1&ITS2) for sequencing in molecular marker. Comparing with controls, strain (A1) Aspergillus niger was superior for biodegradation ability (58%) comparing with Aspergillus polyporicola and Aspergillus spelaeus degrading were showed 47 and 51% respectively. Employed CO₂ evolution as indicator for petroleum oil biodegradation by the fungal isolates reflected that, Aspergillus niger emission highest CO2 (28.6%) comparing with Aspergillus spelaeus and Aspergillus polyporicola which showed 13% and 12.4% respectively. capability of Aspergillus sp. to tolerate and adapted oil pollutants with successful growth rate on them, indicated that it can be employed as mycoremediation agent for recovering restoring ecosystem when contaminated by crude oil.     

Decay and termite resistance of medium density fiberboard (MDF) made from different wood species

Medium density fiberboard (MDF) production worldwide is increasing due to the development of new manufacturing technologies. As a result, MDF products are increasingly utilized in traditional wood applications that require fungal and insect resistance. This study evaluated the ability of white and brown rot fungi and termites to decompose MDF consisting of different wood species by measuring weight loss. Furnish in the boards was prepared from heart and sapwood portions of pine (Pinus nigra Arnold var. pallasiana), beech (Fagus orientalis Lipsky), and European oak (Quercus robur L.) species. Fungal decay resistance tests were performed according to ASTM D 2017-81 standard method using two brown-rot fungi, Gloeophyllum trabeum (Pers. ex Fr.) Murr. (Mad 617), Postia placenta (Fries) M. Larsen et Lombard (Mad 698), and one white-rot fungus, Trametes versicolor (L. ex Ft.) Pilat (Mad 697). MDF and wood specimens were also bioassayed against the eastern subterranean termite, Reticulitermes flavipes (Kollar) in order to determine termite resistance of the specimens. MDF specimens containing oak and mixed furnish demonstrated increased durability against decay fungi. Only pine, oak, and mixed MDF specimens met the 25% or less weight loss limit to be classified resistant according to ASTM D 2017-81 standard method. Overall, MDF specimens made from oak showed better performance than oak solid wood specimens. Accelerated aging according to ASTM D 1037-96a standard method before fungal bioassay decreased fungal resistance of the specimens. In contrast to the fungal bioassay, MDF specimens made from beech and mixed furnish showed decreased weight losses from termite attack after 4 weeks. However, none of the MDF specimens were resistant to termite attack. In severe conditions, the MDFs may require the incorporation of chemical biocides prior to board production for increasing the resistance of MDF to termite attack.     

Chemo-profiling of bioactive metabolites from Chaetomium globosum for biocontrol of Sclerotinia rot and plant growth promotion

Chaetomium globosum Kunze ex. Fries has been known to produce diverse bioactive metabolites, attracting researchers to exploit the biocontrol agent for plant disease management. However, distinct research gaps are visible regarding detail characterization of bioactive metabolites. Thus the current study has been planned to characterize volatile and nonvolatile compounds of most potential strain of C. globosum 5157. GC–MS analysis of hexane fraction revealed twenty-six volatile organic compounds, representing 65.5% of total components in which 3-octanone (21.4%) was found to be most abundant. UPLC-QTOF-MS/MS analysis of ethyl acetate and methanolic fractions resulted tentative characterization of fifteen and eleven metabolites, respectively. Among these, nine metabolites were isolated, purified and characterized using ¹H NMR and High resolution mass spectrometric analysis to delineate mass fragmentation pattern for the first time. Antifungal potential of hexane fraction exhibited high inhibitory action against Sclerotium rolfsii (139.2 μg mL^?1) whereas ethyl acetate fraction was highly effective against Sclerotinia sclerotiorum (112.1 μg mL^?1). Comparative assessment of C. globosum 5157 vis a vis Trichoderma harzianum A28 revealed promising effect of C. globosum 5157 with respect to antifungal properties and plant growth promotion of Brassica seedlings.     

Taxonomic re-evaluation of black koji molds

Black koji molds including its albino mutant, the white koji mold, have been widely used for making the distilled spirit shochu in Northeast Asia because they produce citric acid which prevents undesirable contamination from bacteria. Since Inui reported Aspergillus luchuensis from black koji in Okinawa in 1901, many fungal names associated with black koji molds were reported. However, some species are similar and differentiation between species is difficult. Fungal taxonomists tried to arrange a taxonomic system for black koji molds, but the results were not clear. Recently, multi-locus sequence typing has been successfully used to taxonomy of black Aspergillus. According to β-tubulin and calmodulin gene sequences, black koji molds can be subdivided in three species, A. luchuensis, Aspergillus niger, and Aspergillus tubingensis. Aspergillus awamori, Aspergillus kawachii, Aspergillus inuii, Aspergillus nakazawai, and Aspergillus coreanus are synonyms of A. luchuensis, Aspergillus batatae, Aspergillus aureus (or Aspergillus foetidus), Aspergillus miyakoensis, and Aspergillus usamii (including A. usamii mut. shirousamii) are synonyms of A. niger and Aspergillus saitoi and A. saitoi var. kagoshimaensis are synonyms of A. tubingensis. A. luchuensis mut. kawachii was suggested particular names for A. kawachii because of their industrial importance. The history and modern taxonomy of black koji molds is further discussed.     

Morphological changes of conidiophores and mycelium of some hyphomycetes

The formation of enlarged cells and other abnormalities of mycelium and conidiophores occurring inAspergillus flavus Link,Penicillium chrysogenum Thom,Penicillium notatum Westling,Penicillium variabile Sopp.,Scopularipsis brevicaulis Bainier,Fusarium moniliforme Sheld.,Botrytis cinera Pers. ex Fr.,Botrytis allii Rud.,Humicola brunnea var.africana Fass. andTritirachium heimii var.grisea Fass. under the influence of uranium acetate, radioactive sediment from P?íbram mines (uranium mines in P?íbram, Bohemia), fungicidal compounds (fungizon, fungistatin, nitrofungin), antibiotic nystatin and antifungal bacteriumBacillus subtilis Cohn emend. Prazmowski were investigated. Enlarged phialides or phialides with extended orifices and collarettes and occasionally a conversion of phialides to spherical enlarged cells were observed inAspergillus flavus grown on a Sabouraud agar supplemented with uranium acetate. InPenicillium chrysogenum some conidiophores were completely reduced to enlarged cells. Less abnormalities were observed on the Czapek-Dox agar. The radioactive sediment as a component of malt agar caused either complete reduction of conidiophores inAspergillus flavus to dichotomously branched hyphae or sometimes only an enlargement of phialides. The antifungal effect ofBacillus subtilis was demonstrated in all studied strains. Enlarged cells instead of whole conidiophores were formed under the influence of the bacterium. This effect was observed inBotrytis allii, Botrytis cinerea and to a lesser extent inPenicillium notatum, Aspergillus flavus andFusarium moniliforme. The enlarged cells could still germinate and can be considered as reduced conidiophores. The used fungicidal compounds and the antibiotic nystatin inhibited to a certain degree the studied strains, however, their application did not bring about any abnormalities of mycelium and conidiophores.     

I. Pathogenic variation in fungi and bacteria and mycorrhizal compatibility: Intraspecific variation in a mycorrhizal association

Laboratory studies with combinations of the fly agaric, Amanita muscaria (L. ex Fries) Hooker and birch (Betula pendula (Roth.)) suggest that the genetical control of mycorrhizal formation has features in common with the legume/Rhizobium symbiosis. There are at least four factors that can be genetically controlled by either the host or the fungus: (a) mycorrhizal formation; (b) the extent of mycorrhizal development; (c) the pattern of mycorrhizal branching, and (d) the shape and size of the host root system.     

Three new species of penicillium

Three new species of microfungi belonging to the genus Penicillium Link ex Fries are described and illustrated. All but one have been isolated from the atmosphere of las Palmas, capital city of the island of Gran Canaria (Canary Islands, Spain). They clearly differ from all species of the genus described so far and are, therefore, described and proposed as new species: Penicillium hispanicum sp. nov., Penicillium grancanariae sp. nov., and Penicillium palmensis sp. nov.     

Sucrose Utilization of the Ectomycorrhizal Fungi Amanita muscaria and Hebeloma crustuliniforme Depends on the Cell Wall-bound Invertase Activity of their Host Picea abies

The role of apoplastic invertase (β-d -fructofuranoside — fructohydrolase, EC 3.2.1.26) of the host Picea abies for carbohydrate uptake and growth of two of its natural ectomycorrhiza partners was studied. For that purpose, hyphae of Amanita muscaria (Pers. ex Fries) Hock. and Hebeloma crustuliniforme (Bull. ex Fries) Quell., as well as roots and suspension cultured cells of Picea abies (L.) Karst. were used. Apoplastic invertase activity was demonstrated on roots and suspension cultured cells of spruce (in the latter case with 21.7 nkat (g fresh weight)^?1). Inhibition of the root cell wall invertase activity (pH optimum 4.5) by increasing the apoplastic pH allowed determination of the permanent release of sucrose from the root. However, under in vivo conditions at a lower cell wall pH the hydrolysation products glucose and fructose were predominantly found. In contrast to spruce cells and certain fungi, such as Saccharomyces (Novick et al., 1981) or Phycomyces (Ruiz-Herrera et al., 1989) invertase activity of the mycorrhizal fungi Hebeloma and Amanita was negligibly low. Furthermore, sucrose could not be consumed by Amanita and Hebeloma. As a consequence, cultures of these mycorrhizal fungi starved when kept on media with sucrose as sole carbohydrate source. But addition of invertase initiated hyphal growth immediately. Studies on carbohydrate uptake of host and fungal cells confirmed that the monosaccharides glucose and fructose were readily incorporated by spruce and fungal cells, with a clear preference for glucose. From these results it is suggested that apoplastic invertase activity of the host Picea abies is a precondition for the utilization of sucrose by the studied mycorrhizal fungi during the nutritional interaction of the symbiotic partners.     

Synthesis of a branched d-glucotetraose,the repeating unit of the extracellular polysaccharides of Grifola umbellate,Sclerotinia libertiana,Porodisculus pendulus,and Schizophyllum commune fries

The synthesis of d-glucotetraose, 3-O-[3-O-β-d-glucopyranosyl-β-d-glucopyranosyl]-6-O-β-d-glucopyranosyl-α (and β)-d-glucopyranose, the repeating unit of the extracellular polysaccharides of Grifora umbellata, Sclerotinia libertiana, Porodisculus pendulus, and Schizophyllum commune Fries, is described.     

Synthesis of novel 3-(1-(1-substituted piperidin-4-yl)-1H-1,2,3-triazol-4-yl)-1,2,4-oxadiazol-5(4H)-one as antifungal agents

A novel series of 1,2,3 triazole compounds possessing 1,2,4 oxadiazole ring were efficiently synthesized. Synthesized compounds were evaluated for their in vitro antifungal activities using standard cup plate method. SAR for the series has been developed by comparing their MIC values with miconazole and fluconazole. Compound 11a from the series was more potent than miconazole against Candida albicans (MIC-20) and Aspergillus flavus (MIC-10) whereas equipotent with miconazole against Fusarium oxysporum (MIC-25) and Aspergillus niger (MIC-12.5). Also compound 11h was more potent than miconazole against Candida albicans (MIC-20) and Aspergillus niger (MIC-10) and equipotent with miconazole against Fusarium oxysporum. Compound 11h was equipotent with fluconazole against Aspergillus niger (MIC-10).     

Aflatoxins of Aspergillus flavus Grown on Cassava

Aspergillus flavus Link ex Fries was grown on cassava (Manihot utilissima) and Czapek-Dox media at 31±1°C and 90 per cent relative humidity for 8 weeks. Isolation and purification of the toxic and carcinogenic metabolic products of the mould by paper and thin layer chromatography are described. High concentrations of aflatoxin B1, B2, G1 and G2 were synthesized by the mould grown on cassava for 4 weeks. In addition to these four major toxic components, 9 other fluorescent materials were observed on the chromatograms of crude products from cassava. It is concluded that the high moisture, high polysaccharide and low nitrogen content of cassava constitute a favourable nutritional condition at high temperatures and high relative humidity for the growth of A. flavus and the synthesis of relatively high concentrations of aflatoxin. This conld represent a serious health hazard in the moist tropics.