Microheterogeneity of the primary structure of the short repeated 5S DNA unit in diploid wheat Triticum monococcum L

Nucleotide sequences of two 5S rRNA genes located in repeated 327 bp long units were determined in diploid wheat Triticum monococcum. They were compared with sequences of 5S rRNA genes of Tr. monococcum and Tr. aestivum which were earlier determined. The differences were revealed in two localizations of the nucleotide sequence in 5S DNA coding regions of Tr. monococcum and - in nine localizations in nontranscribed spacer. It was established that the nucleotide sequence of 5S rRNA gene cloned in pTm5S9 plasmid and 5S DNA coding region in Tr. aestivum have significant homology. Diploid wheat Tr. monococcum was supposed to have 5S rRNA genes with different functional activity within one multigene family.     

The poplar ARGOS-LIKE gene promotes leaf initiation and cell expansion,and controls organ size

We identified a Populus nigra auxin-regulated gene involved in organ size (PnARGOS)-LIKE, encoding one organ size related protein in black poplar. It is homologous to AtARGOS and AtARGOS-LIKE genes of Arabidopsis thaliana. ABRE-like, G-box, GATA and I-box motifs were discovered in the promoter region of the poplar ARGOS-LIKE gene. In wild type aspen (Populus tremula) plants, an ortholog of the PnARGOS-LIKE gene (PtrARGOS-LIKE) was noticeably expressed in actively dividing and expanding young leaves and calli, whereas its mRNA content increased in response to exogenous 6-benzylaminopurine, 1-naphthaleneacetic acid, and 24-epibrassinolide. Expression of the PtrARGOS-LIKE gene was reduced under a salinity treatment. In addition, we generated transgenic tobacco and aspen plants with an up-regulated expression of the PnARGOS-LIKE gene. A constitutive expression of the gene contributed to an increase in size of stems and leaves of the transgenic tobacco plants. In the transgenic aspen, a constitutive expression of the PnARGOS-LIKE gene promoted an increase in the frequency of leaf initiations and in leaf length and area. The size of transgenic tobacco and aspen leaves increased due to the enlargement of individual cells. The results show the significance of the PnARGOS-LIKE gene for control of leaf initiation and organ growth by cell expansion in poplar.     

Visual projections in the forebrain of the carp Cyprinus carpio]

In the carp C. carpio, studies have been made on the evoked potentials (EP) in the-forebrain elicited by electrical stimulation of contralateral (with respect to the midbrain tectum) nerve. The most high-amplitude and short-latency EP were recorded in the rostro-lateral part of the forebrain at the depth of 1,000-1,500 mu. According to the topographical nomenclature of cyprinid telencephalon, this region corresponds to the area dorsalis telencephali pars lateralis, whereas according to classic comparative neuroanatomical nomenclature it may be defined as the primordium hippocamp or primordium piriform zone. Comparison of the EP in the telencephalon with those in the midbrain tectum suggests active nature of the former.     

Development and structure of epithelial formations of the connective tissue stroma of human gingiva

Processes of development and structure of epithelial formations, localized in the connective tissue framework of the gingival mucous membrane have been studied. During the prenatal period of development they are presented as epithelial pearls of Serra, and after birth--as remnants of ++tooth-forming epithelium (RTE). They are remnants of sheaths of the destroyed pearls. The latter, like RTE in the gingival stroma, have a genetic connection with the epithelial islets of Malasser and can cause some diseases in the gingiva.     

Morphological and Molecular Analysis of Isolated Cultures of Tobacco Adventitious Roots Obtained by the Methods of Biolistic Bombardment and <Emphasis Type="Italic">Agrobacterium</Emphasis>-Mediated Transformation

Plant infection with Agrobacterium rhizogenes leads to the development of a hairy root disease notable for the rapid agravitropic growth of roots on hormone-free nutrient media. In order to look into the interaction of A. rhizogenes with plants and assess opportunities of practical application of hairy root culture, new approaches to their production are elaborated. A method of bacterium-free and plasmid-free production of genetically modified roots (hairy roots) by means of biolistic transformation of leaf explants with a DNA fragment (size of 5461 bp) consisting of genes rolA, rolB, rolC, and rolD are proposed. In most cases, such transformation resulted in the emergence of only adventitious roots with transient expression of rol-genes, and the growth of such roots on hormone-free media ceased in 2–3 months in contrast to genuine hairy roots capable of unrestricted growth. Molecular analysis of different systems of target genes’ expression showed an important role of transgene rolC and host gene of cyclin-dependent protein kinase CDKB1-1 in the maintenance of rapid growth of hairy roots in vitro (in isolated cultures).     

Estradiol inducible and flower-specific expression of ARGOS and ARGOS-LIKE genes in transgenic tobacco plants

Transgenic tobacco plants expressing Arabidopsis thaliana ARGOS and ARGOS-LIKE genes under the control of the chalcone synthase promoter of Petunia hybrida L., as well as the estradiol inducible XVE system, have been obtained. The part of transgenic plants with flower-specific expression of the target genes was characterized by increased flower size, caused by an increase in cell size and quantity in the case of the ARGOS gene and by a stimulation of cell growth via stretching in the case of the ARGOS-LIKE gene. An enhanced expression level of the NtEXPA1, NtEXPA4 genes encoding expansins, NtEXGT gene encoding endo-xyloglucan transferase, and the AINTEGUMENTA-like gene was detected in the flowers of transgenic tobacco plants. In the case of inducible expression of ARGOS and ARGOS-LIKE genes, an increase in leaf, stem and flower size was revealed in several lines of transgenic plants as compared to control. Expression of the ARGOS gene also affected cell number and size in this case, while the ARGOS-LIKE gene mainly influenced cell size via stretching. Inducible expression of the ARGOS gene in flowers mainly provided an enhanced containment of AINTEGUMENTA-like mRNA, while ARGOS-LIKE gene expression resulted in the activation of NtEXPA1 and NtEXGT genes.