PubMed Health⌕ Search

Biomedical subjects

F R Gimalov

Publications and source records attributed to F R Gimalov.

7 recordsLinked to original sources

Initial stages of low-temperature induction of cabbage cold shock protein gene csp5.

Some stages of low-temperature signal transduction causing appropriate cold stress response in plants are considered. The effects of Ca2+ chelators, Ca2+ channel blockers, and protein kinase inhibitors on protoplasts and plants of cabbage suggest that the initial stages of cold signal transduction are the change in membrane fluidity followed by the activation of calcium channels and elevation of Ca2+ influx into the cytoplasm. Increased concentration of Ca2+ in cytoplasm activates calcium-dependent protein kinase most likely participating in induction of transcription factors necessary for the expression of cold-regulated genes, in particular csp5. The protein kinase inhibitors staurosporine and wortmannin insignificantly repress the expression of csp5.

Brassica↗

The plant dehydrins: structure and putative functions.

This review deals with recent data on the structure and biochemical properties of dehydrins, proteins that are normally synthesized in maturating seeds during their desiccation, and also in vegetative tissues of plants treated with abscisic acid or exposed to environmental stress factors that result in cellular dehydration. The dehydrins are considered as stress proteins involved in formation of plant protective reactions against dehydration. The generally accepted classification of dehydrins is based on their structural features, such as the presence of conserved sequences, designated as Y-, S-, and K-segments. The K-segment representing a highly conserved 15 amino acid motif (EKKGIMDKIKEKLPG) forming amphiphilic alpha-helix has been found in all dehydrins. The pathways of regulation of dehydrin gene expression, putative functions of dehydrins, and molecular mechanisms of their actions are discussed.

Gene Expression Regulation, Plant↗

[Phylogeny of Triticum L. and Aegilops L. genuses inferred from a comparative analysis of nucleotide sequences in promoter rDNA regions of individual species].

The process of accumulation of knowledge on wheat and related wild species during the 20th century is briefly reviewed with special reference to the evidence of the recent years on evolution of polyploid wheats and the role of diploid species. The latter serve as potential donors of the genomes, detection of which is particularly important because of the continuing speciation in the tribe Triticeae and artificial development of synthetic forms. The arguments in favor of the donor role for various diploid wheat species and aegilopses from the section Sitopsis are compared. It is stated that in the formation of the both lines of polyploid wheats turgidum-aestivum and timopheevi, diploid Aegilops speltoides acted as a maternal form. In addition to plasmatic genomes, this aegilops species introduced into them also the B and G nuclear subgenomes. A comparison of nucleotide sequences in the variable part of the promoter of evolutionary conserved rRNA genes in polyploid wheats with their counterparts in diploid wheats and aegilopses confirmed the accepted wheat phylogenies.

Base Sequence↗

[Nucleotide sequences of 5S rRNA genes of polyploid species of wheat and Aegilops species].

Primary structures of 5S rRNA genes and of non-transcribed spacers between them were determined in families of 5S DNA repeats 420 and 500 b.p. long in 8 wheat and Aegilops species. The high conservatism of sequences coding for 5S rRNA, 3'- and 5'-ends of non-transcribed spacers was shown not to depend on the evolutional position, ploidy level and genomic composition of species. The activity of transcription of 5S rRNA cloned genes was determined in vitro. The functional heterogeneity was revealed in each family of repeats due to the existence of exchanges of separate nucleotides within the internal transcription control region. A greater deficiency of CpG dinucleotide was revealed in 5S rRNA genes than in non-transcribed spacers.

Base Sequence↗

[Primary structure of the 5S rRNA gene and its flanking sequences in diploid Aegilops tauschii Coss].

In genome of diploid aegilops A. tauschii (k773) two types of sequences 420 and 510 b. p. long which hybridize with 5S[32P]rRNA were discovered. Using the plasmid pBR327 the recombinant plasmids pAt5S79 and pAt5S91 containing 5S DNA repeats of Ae. tauschii were constructed. The primary structure of 5S rRNA gene and that of intergene spacer cloned in pAt5S79 was determined. In gene region of Ae. tauschii coding for 5S rRNA, as compared with T. aestivum, there were found 3 base substitutions in positions 24, 36 and 37. The homology of spacer sequences is 79.1%. In 5S rRNA gene of Ae. tauschii GC-content is 53.3%, but in a spacer--48.1%. The terminator of transcription in Ae. tauschii includes 15 AT-base pairs with predomination of T-bases in uncoding chain.

DNA↗