Mycelium

About: Mycelium is a research topic. Over the lifetime, 8923 publications have been published within this topic receiving 170993 citations.

Biodegradation of kerosene by Aspergillus ochraceus NCIM-1146

Abstract: The filamentous fungus Aspergillus ochraceus NCIM-1146 was found to degrade kerosene, when previously grown mycelium (96 h) was incubated in the broth containing kerosene. Higher levels of NADPH-DCIP reductase, aminopyrine N-demethylase and kerosene biodegradation activities were found to be present after the growth in potato dextrose broth for 96 h, when compared with the activities at different time intervals during the growth phase. NADPH was the preferred cofactor for enzyme activity, which was inhibited by CO, indicating cytochrome P450 mediated reactions. A significant increase in all the enzyme activities was observed when mycelium incubated for 18 h in mineral salts medium, containing cholesterol, camphor, naphthalene, 1,2-dimethoxybenzene, phenobarbital, n-hexane, kerosene or saffola oil as inducers. Acetaldehyde produced by alcohol dehydrogenase could be used as an indicator for the kerosene biodegradation.

Nutrient content affects the turnover of fungal biomass in forest topsoil and the composition of associated microbial communities

Abstract: Due to the standing biomass and turnover of fungal biomass in forest topsoils, decomposition of fungal biomass represents an important process. Within plant litter, dead fungal biomass represents a unique substrate that is typically nitrogen (N)-rich and is assumed to be subject to rapid decomposition. However, our current knowledge of mycelial decomposition has been largely derived from short-term studies, often limited to a single mycelia type, and the guilds of microbial mycelium decomposers have not yet been described. Furthermore, nutrient content may vary largely in fungal mycelia, and the consequences of this variation are unknown. Here, we followed the decomposition of dead biomass of 12 ectomycorrhizal (ECM) and saprotrophic fungi of a temperate forest using mycobags incubated in litter for 3 and 9 weeks. Loss of substrate dry mass, microbial biomass content and community composition as well as the activity of extracellular enzymes reflecting microbial activity on this substrate were followed. Decomposition rates of fungal biomass were typically high (0.13–0.30 week−1), yet variable. The decomposition includes a rapid initial phase followed by a slower turnover of remaining biomass. The initial nitrogen content that ranged between 1.5% and 10% appeared to be the most important factor that affected colonization of dead mycelia and their decomposition. The relatively high content of N makes fungal mycelia an attractive resource in the N-poor habitat of plant litter. Decomposition of mycelia was performed by a guild of specialist decomposers that showed rather low abundance in surrounding litter and changed during decomposition. Bacteria were much more abundant on dead fungal biomass than in the surrounding litter and appeared to play an important role in decomposition. Fungi associated with dead mycelia were mainly represented by yeasts and moulds. Although the importance of fungal mycelia for the nutrient cycling in forests is not yet clear, the fact that they are turned over rapidly suggests that they may represent an important and dynamic pool of carbon and nitrogen.

The sensitivity of mycelium, arthrospores and microconidia of Trichophyton mentagrophytes to imidazoles determined by in-vitro tests

Abstract: With mycelium, arthrospores and microconidia of trichophyton mentagrophytes as inocula, a variety of in-vitro tests were used to assess the antifungal activity of the imidazoles; miconazole, clotrimazole, ketoconazole, econazole and tioconazole. For mycelial sensitivity, an agar plus method, a microtitre method using fragmented mycelial suspension and a turbidometric method were employed to determine fungistatic effects while a mycelial plug method indicated fungicidal activity. Spore susceptibility was determined by broth dilution and agar dilution methods for fungistatic action, while fungicidal activity was determined by measurement of rate of kill. The results obtained were affected to varying degrees by the test procedure, temperature and time of incubation, medium, pH and solvent. The spore forms were not more resistant than mycelium to the fungistatic effects of the imidazoles. There was little to choose between the various imidazoles in respect to their performance in these tests, with the exception of ketoconazole, which consistently gave higher MICs.

Detection and location of seed-borne inoculum of Ascochyta rabiei and its transmission in chickpea (Cicer arietinum).

Abstract: A. rabiei infected 70% of C. arietinum samples from C. Anatolia, Turkey. The standard blotter method, using 5 seeds/Petri dish and 12 h NUV 12 h darkness cycles at 22 deg C, proved most suitable for detecting the fungus. The inoculum was spore contamination and mycelium occurred in the seed coat alone or in seed coat and embryo. Pycnidia were observed only in the seed coat of seeds having deep lesions. Inter- and intracellular mycelium was localized to lesions. Pycnidia were subepidermal and contained mature spores. Pycnidiospores obtained from the seed surface and pycnidia from 14-month-old seed stored at 3 plus or minus 2 deg showed 33% germination. The light and temp. responses of the fungus on PDA revealed that opt. colony growth occurred at 19 deg . Pycnidial formation was max. under NUV but failed in darkness. Both superficial and deep infections were equally potent in the transmission of the disease. The fungus was highly pathogenic to seed and 40-day-old plants.This paper was presented at the 17th Int. Seed Testing Congress 1974.