L1 (LINE-1) retrotransposable elements provide a "fossil" record of the phylogenetic history of murid rodents

The single most difficult problem in phylogenetic analysis is deciding whether a shared taxonomic character is due to common ancestry or one that appeared independently due to convergence, parallelism, or reversion to an ancestral state. Mammalian L1 retrotransposons undergo periodic amplifications in which multiple copies of the elements are interspersed in the genome. Because these elements apparently are transmitted only by inheritance and are retained in the genome, a shared L1 amplification event can only be an inherited ancestral character. We propose that L1 amplification events can be an excellent tool for analyzing mammalian evolution and demonstrate here how we addressed several refractory problems in rodent systematics using L1 DNA as a taxonomic character.      

The sources of the innervation of the sphincter of the esophagogastric junction in rats]

The investigation has been performed by means of the luminescent microscopical method. The retrograde axonal transport of the fluorescent marker primuline has demonstrated that a definite amount of labelled cells are observed in the celiac plexus, in nodes of the thoracic part of the sympathetic trunk (predominantly in Th6-Th8). Innervation of the EGP sphincter is mainly performed from the sympathetic trunk nodes (Th6-Th8) and from the celiac plexus.     

Multiple recording of electromyograms in a chronic experiment

The authors describe electromyographic electrodes (EMG electrodes) for recording the activity of several muscles in chronic experiments on cats. An EMG electrode is a loop made of a silver wire 200 micron in diameter and 1.5-2 cm long, to which a flexible copper wire insulated with teflon 300 micron in diameter is soldered. The soldering site is insulated with biologically indifferent material. The EMG electrodes turned out fairly good in numerous experiments.     

Minicircular Kinetoplast DNA of Trypanosomatidae

Analysis of primary structure and organization of mitochondrial (kinetoplast) DNA of flagellates occupies a prominent place in the studies of eukaryote mitochondrial genomes, owing to its unusual organization and functioning as well as to the epidemiological role of the Trypanosomatidae family. According to contemporary notions, living zooflagellates are direct descendants of the ancestral forms that gave rise to all eukaryotic kingdoms. Hence, comparative mtDNA studies of recent Trypanosomatidae open broad prospects for phylogenetic reconstructions and analysis of presumable routes of eukaryote evolution. The structure, characteristics, and functions of Trypanosomatidae minicircular kinetoplast DNA are discussed here.     

Metalloporphyrins and molecular complexes of amino acids with porphyrins in juvenile volcanic ash

In samples of juvenile ash of the volcano Tjatja, USSR (that erupted in 1973) metalloporphyrins were found. With respect to the fluorescence spectra free bases of the compounds were close to the pigments that formed in abiogenic synthesis experiments (predominance of long-wave length fluorescence band). The pigments detected occurred in the ash as molecular complexes with amino acids which seem to be of abiogenic origin. These findings are of interest in terms of exploration of the processes of chemical evolution and emergence of life on the Earth.