The ecology of a late Visean forest at Catcraig (East Lothian,Scotland) based on multiproxy study of paleosol and root-casts

The Middle Longcraig Limestone (late Visean) at Catcraig, Scotland, is densely covered with large (about 1 m in diameter) hollows, which are surrounded by numerous fossilized roots. The latter represent the positions of tree-sized plants belonging to a fossil forest. This paper aims to reconstruct its ecology based on paleosol properties, size and spatial distribution of root-casts, rooting system morphology and characteristics of coalified plant remnants. The obtained data are consistent with the supposition that the Visean peat wetland forest of Catcraig represents a Cordaitalean dominated community composed of mono-sized, most probably, even-aged giant trees. The peaty paleosol (Histosol) contains pyrite and siderite, indicating reducing and acidic conditions, whilst the abundant presence of gypsum testifies periods of elevated salinity. The adaptation of trees to such conditions is supported by morphologically evident large root mass (typically more than 1000 individual roots per cast). Good preservation of plant tissues in peat, in addition to other paleosol and rooting system characteristics allow us to conclude that the trees occupied seacoast settings or lagoons, which were not permanently flooded.     

Congruent population genetic structures and divergence histories in anther‐smut fungi and their host plants Silene italica and the Silene nutans species complex

Study of the congruence of population genetic structure between hosts and pathogens gives important insights into their shared phylogeographical and coevolutionary histories. We studied the population genetic structure of castrating anther‐smut fungi (genus Microbotryum) and of their host plants, the Silene nutans species complex, and the morphologically and genetically closely related Silene italica, which can be found in sympatry. Phylogeographical population genetic structure related to persistence in separate glacial refugia has been recently revealed in the S. nutans plant species complex across Western Europe, identifying several distinct lineages. We genotyped 171 associated plant–pathogen pairs of anther‐smut fungi and their host plant individuals using microsatellite markers and plant chloroplastic single nucleotide polymorphisms. We found clear differentiation between fungal populations parasitizing S. nutans and S. italica plants. The population genetic structure of fungal strains parasitizing the S. nutans plant species complex mirrored the host plant genetic structure, suggesting that the pathogen was isolated in glacial refugia together with its host and/or that it has specialized on the plant genetic lineages. Using random forest approximate Bayesian computation (ABC‐RF), we found that the divergence history of the fungal lineages on S. nutans was congruent with that previously inferred for the host plant and probably occurred with ancient but no recent gene flow. Genome sequences confirmed the genetic structure and the absence of recent gene flow between fungal genetic lineages. Our analyses of individual host–pathogen pairs contribute to a better understanding of co‐evolutionary histories between hosts and pathogens in natural ecosystems, in which such studies remain scarce.     

Clear-cutting impacts nutrient,carbon and water exchange parameters in woody plants in an east Fennoscandian pine forest

Plant and Soil - Clear-cut logging currently is a key factor transforming forest communities in many boreal regions. The dynamics of biogeochemical processes taking place in clear-cuts makes them a...     

A synergy of activity,stability, and inhibitor‐interaction of HIV‐1 protease mutants evolved under drug‐pressure

A clinically‐relevant, drug‐resistant mutant of HIV‐1 protease (PR), termed Flap+_(I54V) and containing L10I, G48V, I54V and V82A mutations, is known to produce significant changes in the entropy and enthalpy balance of drug‐PR interactions, compared to wild‐type PR. A similar mutant, Flap+_(I54A), which evolves from Flap+_(I54V) and contains the single change at residue 54 relative to Flap+_(I54V), does not. Yet, how Flap+_(I54A) behaves in solution is not known. To understand the molecular basis of V54A evolution, we compared nuclear magnetic resonance (NMR) spectroscopy, fluorescence spectroscopy, isothermal titration calorimetry, and enzymatic assay data from four PR proteins: PR (pWT), Flap+_(I54V), Flap+_(I54A), and Flap+_(I54), a control mutant that contains only L10I, G48V and V82A mutations. Our data consistently show that selection to the smaller side chain at residue 54, not only decreases inhibitor affinity, but also restores the catalytic activity.     

Cytotoxic Effects of the Selective Ligands of Membrane Progesterone Receptors in Human Pancreatic Adenocarcinoma Cells BxPC3

Biochemistry (Moscow) - Progesterone and its synthetic analogues act on cells through different types of receptors, affecting proliferation and apoptosis. These compounds exert their effect through...     

Mitochondrial Disorders in Alzheimer’s Disease

Biochemistry (Moscow) - Alzheimer’s disease is the most common age-related neurodegenerative disease. Understanding of its etiology and pathogenesis is constantly expanding. Thus, the...