6 research outputs found
Morphological, Karyological and Molecular Characteristics of Festuca arietina Klok. – a Neglected Psammophilous Species of the Festuca valesiaca agg. from Eastern Europe
Until recently, Festuca arietina was practically an unknown species in the flora of Eastern Europe. Such a situation
can be treated as a consequence of insufficient studying of Festuca valesiaca group species in Eastern Europe
and misinterpretation of the volume of some taxa. As a result of a complex study of F. arietina populations from
the territory of Ukraine (including the material from locus classicus), Belarus and Lithuania, original anatomy,
morphology and molecular data were obtained. These data confirmed the taxonomical status of F. arietina as
a separate species. Eleven morphological and 12 anatomical characters, ITS1-5.8S-ITS2 cluster of nuclear ribosomal
genes, as well as the models of secondary structure of ITS1 and ITS2 transcripts were studied in this
approach. It was found for the first time that F. arietina is hexaploid (6x = 42), which is distinguished from all
the other narrow-leaved fescues by specific leaf anatomy as well as in ITS1-5.8S-ITS2 sequences. Molecular data
indicating possible hybridogenous origin of F. arietina, fall in line with the anatomical-morphological data and
explain the tendency toward sclerenchyma strands fusion with formation of a continuous ring in F. arietina, as
well as F. arietina ecological confinement to psammophyte biotopes
Hippocampal long-term potentiation and neural cell adhesion molecules L1 and NCAM
Synaptic membranes express cell adhesion molecules. Here we investigate the role of the neural cell adhesion molecules L1 and NCAM in hippocampal long-term potentiation (LTP), a sustained-use-dependent increase in synaptic efficacy that has been implicated in learning and memory. L1 and NCAM mediate cell interactions during neural development and are strongly expressed in the hippocampus. They cooperate to strengthen L1-dependent cell adhesion and are coupled to second messenger pathways. We show that LTP in CA1 neurons of rat hippocampal slices was reduced by application of various L1 and NCAM antibodies, recombinant L1 fragments, and upon dissociation of the L1/NCAM complex through oligomannosidic carbohydrates and NCAM peptides. Neither the activation of NMDA (N-methyl-D-aspartate) receptors nor the maintenance of LTP was affected. These results suggest that L1 and NCAM modulate the development or the stabilization of LTP