Evolution of photosystems of photosynthetic organisms

It is generally accepted that two photosystems function successively in photosynthetic electron transport chain of plants and algae. The interaction of these photosystems results in the enhancement of photosynthesis. It was suggested that only one photosystem is present in purple bacteria, the most primitive photosynthetic organisms. The functioning of this photosystem is accompanied by absorption changes at 890 nm. Recently new spectral changes were found inChromatium chromatophores under reductive conditions, more favorable for bacterial growth. Some of that spectral changes take place even atliquid nitrogen temperature. It is proposed these absorption changes could be related to other photosystem functioning in low potential region. Such a photosystem is necessary for reduction of NAD inChromatium, for which the reverse electron transport to NAD was not shown. In contrast to photosystems of plants, the bacterial photosystems appear to function independently because the enhancement of bacterial photosynthesis is not found. Apparently the evolution of photosystems involved interaction between independent photosystems, one of them functioning under more oxidative conditions.     

Genetic polymorphism of <Emphasis Type="Italic">Microbotryum violaceum</Emphasis> s. l. Isolates collected from different plant species on the territory of Russia

The present-day studies in the field of systematics and phylogeny of microorganisms, fungi, in particular, are characterized by a wide use of new approaches and methods of molecular biology. The use of a diversity of genetic markers permits a distinct differentiation of closely related species into individual evolutionarily independent lines. It is shown in this work that all Microbotryum violaceum s. l. isolates studied by us are divided into five evolutionary groups according to the host plant.