The fungus Penicillium variabile Sopp 1912 isolated from permafrost deposits as a producer of rugulovasines

It has been established that relict fungi Penicillium variabile Sopp can synthesize clavine alkaloids, rugulovasines A and B, which are revealed in this species for the first time. Submerged cultivation of the strain-producer revealed several microcycles of conidia formation. The synthesis of alkaloids was also of a cyclic character. The synchronism of cyclic rugulovasine biosynthesis and conidia formation was revealed. Zinc ions stimulated fungal growth but had a negative effect on the biosynthesis of rugulovasines.     

Microbial communities of ancient seeds derived from permanently frozen Pleistocene deposits

Microbial communities from the surface of ancient seeds of higher plants and embedding frozen material dated to the late Pleistocene (formed about 30 thousand years ago) were studied by various methods: scanning electron microscopy, epifluorescence microscopy, and inoculation of nutrient media, followed by identification of isolated cultures. Both prokaryotic and eukaryotic microorganisms were found on the surface of ancient seeds. The total quantity of bacterial cells determined by direct counting and dilution plating (CFU) for the samples of ancient seeds exceeded the value in the embedding frozen material by one to two orders of magnitude. This pattern was not maintained for mycelial fungi; their quantity in the embedding material was also rather high. A significant difference was revealed between the microbial communities of ancient seeds and embedding frozen material. These findings suggest that ancient plant seeds are a particular ecological niche for microorganisms existing in permafrost and require individual detailed study.     

The Fungus Penicillium citrinum Thom 1910 VKM FW-800 Isolated from Ancient Permafrost Sediments As a Producer of the Ergot Alkaloids Agroclavine-1 and Epoxyagroclavine-1

The study of the secondary metabolites of the relict strain Penicillium citrinum VKM FW-800 isolated from ancient Arctic permafrost sediments showed that this fungus produces agroclavine-1 and epoxyagroclavine-1, which are rare ergot alkaloids with the 5R,10S configuration of the tetracyclic ergoline ring system. The production of the alkaloids by the fungus showed a biphasic behavior, being intense in the phase of active growth and slowing down in the adaptive lag phase and in the stationary growth phase. The addition of zinc ions to the incubation medium led to a fivefold increase in the yield of the alkaloids. The alkaloid-producing Penicillium fungi isolated from different regions exhibited the same tendencies of growth and alkaloid production.     

Production of mycophenolic acid by fungi of the genus <Emphasis Type="Italic">Penicillium</Emphasis> link

Out of 36 strains of fungi of the genus Penicillium, some of which were isolated from ancient permafrost, 14 strains synthesized mycophenolic acid (MPA). Maximal (over 500 mg/l) accumulation of MPA in culture liquid was observed in P. brevicompactum strains (VKM F-457, VKM F-477, and VKM F-1150). This was the first study to detect MPA in representatives of the species P. rugulosum; in three strains of this species (VKM FW-665, VKM FW-717, and VKM FW-733), the level of MPA accumulation exceeded 300 mg/l. The time course of the synthesis of MPA by P. rugulosum strain VKM FW-733 was studied. It was shown that the synthesis of this metabolite was dramatically intensified during the stationary growth phase (ten days).Translated from Prikladnaya Biokhimiya i Mikrobiologiya, Vol. 41, No. 1, 2005, pp. 95–98.Original Russian Text Copyright © 2005 by Vinokurova, Ivanushkina, Kochkina, Arinbasarov, Ozerskaya.     

Lipid synthesis by <Emphasis Type="Italic">Geomyces pannorum</Emphasis> under the impact of stress factors

Lipogenic activity and fatty acid composition of two strains of Geomyces pannorum were studied in the course of fungal growth. The strains were isolated from an Arctic cryopeg lens (VKM FW-2241) and from Central Russia (VKM F-3808). The adaptive reactions in both strains towards the temperature decreasing to 2°C involved intensification of the fatty acid desaturation. The degree of lipid unsaturation increased mainly due to a higher amount of α-linolenic acid (α-C_18:3) especially in the case of strain VKM FW-2241. Elevated NaCl concentration in the medium enhanced the level of linoleic acid (C_18:2) which apparently played a specific role in osmoprotection. Strain VKM FW-2241 was more tolerant to increased salinity than strain VKM F-3808. Almost complete inhibition of the growth of strains VKM F-3808 and VKM FW-2241 occurred at salinity of 10 and 20%, respectively; however, the viability of the strains was not affected. Under the combined effect of high salinity and hypothermia, the ratio between C_18:2 and α-C_18:3 acids was intermediate, indicating that these acids were involved in two adaptation mechanisms. The inhibition of fungal growth under stress was found to result in lipid overproduction. An increased pool of energy-rich lipids in fungi possibly contributes to their strategy of cell survival.     

New producers of biologically active compounds—fungal strains of the genus <Emphasis Type="Italic">Penicillium</Emphasis> isolated from permafrost

Screening of producers of secondary metabolites was carried out among 25 fungal strains of Penicillium genus isolated from permafrost in Arctic and Antarctic regions and Kamchatka. Nearly 50% of the investigated strains synthesize biologically active substances of alkaloid nature: ergot alkaloids, diketopiperazinees, and quinoline derivatives. A large group of the identified metabolites belongs to mycotoxins. A strain of Penicillium waksmanii was found producing epoxyagroclavine-I and quinocitrinines. The main physiological and biochemical characteristics of this producer were investigated.     

Secondary metabolites of <Emphasis Type="Italic">Penicillium</Emphasis> fungi isolated from permafrost deposits as chemotaxonomic markers

Species identification of slow-growing fungi of the genus Penicillium isolated from ancient permafrost deposits was performed using micro- and macromorphological characteristics as well as the composition of secondary metabolites. The strains producing clavine ergot alkaloids fumigaclavines A and B and festuclavine were assigned to the species P. palitans Westling 1911, whereas the strains forming ochratoxins A and B were identified as P. verrucosum Dierckx 1901.     

Fungal diversity in the Antarctic active layer

Taxonomic diversity of fungi in the samples of the active layer of Antarctica was investigated using conventional microbiological techniques and metagenomic analysis of total DNA extracted from environmental samples. The list of Antarctic microscopic fungi was expanded, including detection of the species representing a portion of the fungal complex which is nonculturable or sterile on conventional nutrient media.     

OECD Best Practice Guidelines for Biological Resource Centers. OECD, 2007, 115 p.

The book is the first published collection of guidelines regulating operational activities of biological resource centers, approved by representatives of the 30 member nations of the Organization for Economic Cooperation and Development (OECD). The published standards were prepared as a result of multiple discussions held by expert groups of the OECD members, together with key experts of partner nations, under the auspices of a specialist task force established by the OECD Working Party on Biotechnology.     

Autoregulation of Conidium Germination in Micromycetes of the genus Trichoderma

The amount of germinated conidia of micromycetes belonging to the genus Trichoderma considerably decreased with an increase in the population density. Strains exhibited different ecological strategies. The maximum number of germinated conidia (30–70%) was recorded when the average distance between conidia was 50 m.