Differential Participation of Central L-Glutamate Receptors of non-NMDA-Subtype in Associative Learning of the Honeybee Apis mellifera

Participation of non-NMDA-receptors in associative learning in the honeybee was analyzed using a complex approach. There were studied effects of systemic and intracerebral AMPA injections on retention of the elaborated conditional reflex in short-term memory, on dynamics of the bioelectrical activity of neurons of calyx of the mushroom bodies, and on the limb locomotor activity. It has been shown that the systemic and intracerebral AMPA injections stimulate processes of short-term memory and activate bioelectrical activity of neurons of the mushroom body medial calyx. Antagonist of AMPA-receptors NS-257 HCl suppressed spontaneous activity of these neurons. The observed processes did not depend on the character of locomotor activity. These results confirm the hypothesis proposed earlier about involvement of non-NMDA-receptors in the process of associative learning.     

Using RAPD for Estimating Genetic Polymorphism in and Phylogenetic Relationships among Species of the Genus Lycopersicon (Tourn.) Mill.

RAPD genome analysis of 53 species and cultivars of the genusLycopersicon (Tourn.) Mill. revealed their high genetic polymorphism (Tourn.) Mill., based on which their phylogenetic relationships were inferred. In total, 248 polymorphic DNA fragments were amplified. Intraspecific polymorphism was maximum (79%) in L. peruvianum and minimum (9%) in L. parviflorum. In general, genome divergence among cross-pollinating tomato species was substantially higher than in self-pollinating species. An UPGMA dendrogram constructed from the RAPD patterns was consisted with the Lycopersicon phylogeny inferred from the molecular data of RFLP, ISSR, and microsatellite analyses and with a classification based on morphological characters. The relationships of taxa within the genus Lycopersicon are discussed.     

Further studies on the role of cell-wall-degrading enzymes in cell-wall loosening in oat coleoptiles

A fungal endo-ß-l,3-glucanase was compared with afungal exo-ß-1,3-glucanase with respect to their effectson elongation and cell-wall extensibility in oat coleoptilesegments. The exo-enzyme enhanced elongation and extensibilityof the cell wall. Its effect was not additive to the effectof indole-3-acetic acid when given together with the latter,at least during 3 hr of incubation. Endo-glucanase showed nosignificant effect on elongation and no interaction with theexo-enzyme. Auxin and exo-glucanase increased extensibilityof the cell wall. The exo-glucanase was separated by isoelectricfocusing. The two fractions which were separated and showedglucanase activity induced elongation and cell wall loosening. (Received March 16, 1970; )     

Novel aryl and heteroaryl substituted N-[3-(4-phenylpiperazin-1-yl)propyl]-1,2,4-oxadiazole-5-carboxamides as selective GSK-3 inhibitors

Synthesis, biological evaluation, and SAR dependencies for a series of novel aryl and heteroaryl substituted N-[3-(4-phenylpiperazin-1-yl)propyl]-1,2,4-oxadiazole-5-carboxamide inhibitors of GSK-3beta kinase are described. The inhibitory activity of the synthesized compounds is highly dependent on the character of substituents in the phenyl ring and the nature of terminal heterocyclic fragment of the core molecular scaffold. The most potent compounds from this series contain 3,4-di-methyl or 2-methoxy substituents within the phenyl ring and 3-pyridine fragment connected to the 1,2,4-oxadiazole heterocycle. These compounds selectively inhibit GSK-3beta kinase with IC(50) value of 0.35 and 0.41 microM, respectively.     

A FAK/Src chimera with gain-of-function properties promotes formation of large peripheral adhesions associated with dynamic actin assembly

Formation of a complex between the tyrosine kinases FAK and Src is a key integrin-mediated signaling event implicated in cell motility, survival, and proliferation. Past studies indicate that FAK functions in the complex primarily as a "scaffold," acting to recruit and activate Src within cell/matrix adhesions. To study the cellular impact of FAK-associated Src signaling we developed a novel gain-of-function approach that involves expressing a chimeric protein with the FAK kinase domain replaced by the Src kinase domain. This FAK/Src chimera is subject to adhesion-dependent activation and promotes tyrosine phosphorylation of p130Cas and paxillin to higher steady-state levels than is achieved by wild-type FAK. When expressed in FAK -/- mouse embryo fibroblasts, the FAK/Src chimera resulted in a striking cellular phenotype characterized by unusual large peripheral adhesions, enhanced adhesive strength, and greatly reduced motility. Live cell imaging of the chimera-expressing FAK -/- cells provided evidence that the large peripheral adhesions are associated with a dynamic actin assembly process that is sensitive to a Src-selective inhibitor. These findings suggest that FAK-associated Src kinase activity has the capacity to promote adhesion integrity and actin assembly.     

Analysis of chloroplast <Emphasis Type="Italic">rpS16</Emphasis> intron sequences in Lemnaceae

Chloroplast rpS16 gene intron sequences were determined and characterized for twenty-five Lemnaceae accessions representing nine duckweed species. For each Lemnaceae species nucleotide substitutions and for Lemna minor, Lemna aequinoctialis, Wolffia arrhiza different indels were detected. Most of indels were found for Wolffia arrhiza and Lemna aequinoctialis. The analyses of intraspecific polymorphism resulted in identification of several gaplotypes in Lemna gibba and Lemna trisulca. Lemnaceae phylogenetic relationship based on rpS16 intron variability data has revealed significant differences between Lemna aequinoctialis and other Lemna species. Genetic distance values corroborated competence of Landoltia punctata separations from Spirodela into an independent generic taxon. The acceptability of rpS16 intron sequences for phylogenetic studies in Lemnaceae was shown.     

NBS-ARC domain variability of Rx1 homologues of cultivated potato and related wild species

In the present work NBS-ARC domain sequences of Rx1 homologues of ten accessions of cultivated and wild potato species which differ in susceptibility to potato virus X were obtained and studied. Within the NBS-ARC domain different indels and nucleotide/amino acid substitutions, including substitutions in the conservative motives of the domain were detected. There were no direct associations between the mutational changes found in the conservative motives of the NBS-ARC domain and the susceptibility of the studied accessions to X virus.     

Phylogenetic relationships among <Emphasis Type="Italic">Fagopyrum</Emphasis> species based on analysis of the <Emphasis Type="Italic">nad1</Emphasis> Gene b/c intron

For the first time, the b/c intron of the nad1 gene was characterized in 13 species of Fagopyrum and the applicability of the intron was demonstrated for identification of buckwheat species. The length of the b/c intron of the nad1 gene varied from 1217 bp in F. tataricum and F. cymosum to 1239 bp in F. capillatum. Species-specific SNPs and indels were identified. The genus phylogeny that was determined with the molecular approach correlated with phylogenetic data that are based on morphological characteristics. The NJ and MP dendrograms revealed distinct division of the analyzed species into two main groups, cymosum and urophyllum. The species of the urophyllum group were characterized by the presence of several synapomorphic substitutions and indels, including the insertion of 11 nucleotides, which is flanked by direct repeats.     

Evolutionary history of tall fescue morphotypes inferred from molecular phylogenetics of the <Emphasis Type="Italic">Lolium</Emphasis>-<Emphasis Type="Italic">Festuca</Emphasis>species complex

Background  

The agriculturally important pasture grass tall fescue (Festuca arundinacea Schreb. syn. Lolium arundinaceum (Schreb.) Darbysh.) is an outbreeding allohexaploid, that may be more accurately described as a species complex consisting of three major (Continental, Mediterranean and rhizomatous) morphotypes. Observation of hybrid infertility in some crossing combinations between morphotypes suggests the possibility of independent origins from different diploid progenitors. This study aims to clarify the evolutionary relationships between each tall fescue morphotype through phylogenetic analysis using two low-copy nuclear genes (encoding plastid acetyl-CoA carboxylase [Acc1] and centroradialis [CEN]), the nuclear ribosomal DNA internal transcribed spacer (rDNA ITS) and the chloroplast DNA (cpDNA) genome-located matK gene. Other taxa within the closely related Lolium-Festuca species complex were also included in the study, to increase understanding of evolutionary processes in a taxonomic group characterised by multiple inter-specific hybridisation events.