Influence of extreme ambient temperatures and anaerobic conditions on Peltigera aphthosa (L.) Willd. viability.

Lichen are symbiotic systems constituted by heterotrophic fungi (mycobionts) and photosynthetic microorganism (photobionts). These organisms can survive under extreme stress conditions. The aim of this work was to study the influence of low (-70 °C) or high (+70 °C) temperatures, temperature fluctuations from +70 °C to -70 °C, and anaerobic conditions on P. aphthosa (L.) Willd. viability. None of the studied stress factors affected significantly photosynthetic and respiratory activity of the thalli. No changes in morphology or ultrastructure of the cells were revealed for both photobiont and mycobiont components after extreme temperature treatment of P. aphthosa thalli. The data show the extreme tolerance of P. aphthosa to some stress factors inherent to the space flight conditions.

[Endomembrane system of fungi: traditional and modern conceptions].

The review is devoted to the endomembrane system in Fungi, which is mostly presented in cell by membrane organelles, taking part in exo- and endocytosis. Main tenets of the modern model of exo- and endocytosis are covered by the example of the apical cells of filamentous fungi. Particular attention is given to studies of endomembrane system, which were carried out by electron microscopy in the last century--the era in science preceding the prevalence of methods of fluorescence microscopy, immune and molecular genetic tagging. Endomembrane organelles, which are described in classical studies, but have not been identified or differentiated from other organelles modern specialists are under consideration. Among these organelles are lomasomes, plasmalemmasomes, membranosomes and myelin-like bodies. Possible reasons for the "loss" of given structures in today's science and its place in modern proposed model of endomembrane system are discussed. In addition, some specific questions are mentioned, namely: the presence of mushroom mycelium endobionts, morphologically similar to endomembrane organelles, and the increase of number of endomembrane structures in bracket fungi, limited in nitrogen nutrition.

[Report of Quambalaria cyanescens associated with birch].

Long-term microbiological investigation of the pollen of silver birch (Betula pendula) in the Mos- cow, and Moscow region areas revealed that: almost one-third of the analyzed samples, contained the fungus identified by morphological, cultural, and molecular genetic techniques as Quambalaria cyanescens (de Hoog & G. A. de Vries) Z.W. de Beer, Begerow & R. Bauer. This species was previously known mostly as a syrmbiont of tropical plants of the generaEucalyptus and Cortyminbia and has not been isolated in Russia. We revealed a close association between Quambalaria cyanescens and silver birch. The micromycete was regulaly detected in pollen samples, as well as on the.inside and outside of the aments, on the surface of leaves and branches. It was never isolated from other plant species in the investigated area. The data on the morphological and cultural characteristics of the fungus, its cell ultrastructure, and occurrence are presented, as well as the phylogenetic analysis of the isolated strains.

[Differentiation of closely related oyster fungi Pleurotus pulmonarius and P. ostreatus by mating and molecular markers].

Classical matings and RAPD-PCR analysis were used to differentiate two closely related basidial fungi, Pleurotus pulmonarius and P. ostreatus, which are widespread in Russian forest biocenoses with moderate climate. Monokaryon-monokaryon (mon-mon) and dikaryon--monokaryon (di-mon) matings demonstrated complete reproductive isolation of the two species, which have partly overlapping morphological traits. The prevalence of a particular species in nature was shown to depend to a great extent on the natural conditions, namely, the day and night temperature ranges. The clustering of natural Pleurotus strains displayed two trends: one was associated with natural reproductive isolation of the two species (D = 0.61) and the other, with the geographical factor (D = 0.39). A relatively recent origin is suggested for the divergence of the two species and the reproductive barrier between them. Adaptation to natural conditions was considered to be the main factor causing the divergence of natural Pleurotus populations and, eventually, allopatric speciation.

[Comparative analysis of Pleurotus ostreatus natural isolates].

A comparative analysis is performed of the polymorphism of the Pleurotus ostreatus (Fr.) Kumm naturally occurring strains isolated from the natural substrates found in two geographically remote Russian natural preserves, the Central Arboreal Biosphere Tver State Preserve (CABTSP) and the Moscow State University Zvenigorod Biological Station (ZBS, Moscow oblast), and within the city of Moscow. The results of the frequency analysis for the isozyme loci alleles and for the sexual and vegetative incompatibility groups are presented; the genetic structure and the interpopulation relations among 58 P. ostreatus dikaryotic strains are estimated. The natural samples from the Moscow and Tver oblasts are shown to have a high degree of polymorphism with a genetic differentiation of 0.743; in spite of their territorial remoteness, they are, however, actively exchanging genetic material. The natural fungal isolates form two reproductively isolated groups.