Advances and Main Results

Laboratory of Molecular Biology Of Cell

Main Results

Over the years of more than 60-year existence of the laboratory, the conception of structural-functional chlorophyll organization in chloroplast, heterogeneity of its pigment stock and character of pigment relations to chloroplast carbon and phosphorus were stated. Radio-active isotopes of carbon and phosphorus were applied in Belarus for the first time in studying biosynthesis of pigments and their organization in chloroplast membranes. Interaction of chlorophyll and carotenoid biosynthesis was revealed.

The basic unity of molecule structure in protochlorophyll pigment of higher angiosperms was proved. Protochlorophyllide was revealed to be a direct precursor of chlorophyllide.

Dark conversion of protochlorophyllide was performed by an enzymatic way in higher plants. Chlorophyll-free character of the relationship between the amount of recovered protochlorophyllide and light intensity was established.

The ability of evergreens to synthesize photosynthetic pigments at temperatures below 0ºC was revealed.

Constancy of chloroplast morphological integrity under any period of leaf vegetation was proved.

Interrelation between reduction in the photosynthetic activity of an evergreen leaf in ontogenesis and decrease in the functioning activity of pigment biosynthesis system, associated with disturbance in optimum chlorophyll organization in chloroplast membranes, was detected.

It was established that a short-waved protochlorophyllide form absorbing light at 634 nm was a precursor photoactive protochlorophyllide during ontogenesis. Research work on studying biophysical mechanisms of photoreceptor processes in animal and plant organisms were proceeded.

In the field of visual reception, the structural dynamics of rhodopsin and photoreceptor membranes was studied. Photoregulatory reactions were investigated in photoreceptor cells under photocontrol of Ca2+-flows within membrane compartments. The cGMP bound state in rod outer segment was revealed, with specific centres of its binding being identified in photoreceptor membrane. Metabolism of phosphoinositides in photoreceptor membranes was studies, with the regulatory role of inositol triphosphate being shown under its effect on intracellular Ca2+ stores.

Genes of regulatory proteins of human retina and lymphocytes were cloned. A complete coding cDNA sequence of Csk protein tyrosine kinase was obtained from human (Homo sapiens) blood lymphocytes. The method for diagnosing diseases of organs of vision was developed based on PCR analysis of Csk-tyrosine kinase gene.

The method for detecting restriction fragment length polymorphism (RFLP) was developed for revealing RYR1 gene mutation associated with malignant hyperthermia in animals.

The works are under way for determining genotoxicity of carbon nanotubes used in electronic industry.

In the field of plant photoreception, an original technique was developed for extracting photoreceptor phytochrome protein from plant tissue. Conformation differences in red and far-red photoreceptor farms were detected by some physicochemical approaches.

Final stages of phytochrome phototransformation were studied by flash photolysis and nanosecond spectroscopy that made it possible to describe the so-called pool of “late intermediates”. Phytochrome control of Ca2+ flow efficiency in plant cell was detected. Ca2+ was shown to be a basic mediator of information exchange during intracellular signaling. Metabolism distinctions of phosphoinositides and cyclic nucleotides were show in plant cell. The nature and role of some intermediates in the transduction chain of phytochrome and phytohormonal effects were revealed.

Vectors for insertion plant mutagenesis were designed with T-DNA jointly with the Institute of General Genetic named after N.I.Vavilov at the Russian Academy of Sciences. Genetic constructions were designed for posttranscriptional inhibition of phytochrome gene expression using techniques of antisense RNA. Tobacco transgenic plants with low content of phytochrome A were produced that made it possible to get new information on the role of this protein in photocontrol mechanisms at the molecular-biological level in plant cell. Genetic constructions were designed for posttranscriptional modification of phospholipase C gene expression in plant cells. Potato transgenic plants of Byelorussian cultivars expressing one of the cecropin P1 gene forms were produced jointly with the Branch of the Institute of Bioorganic Chemistry at the Russian Academy of Sciences. Genetic constructions were designed for synthesizing cecropin-mellitin hybrids in potato plant cells.

Inventions

Seven inventor’s certificates and two patents of the Republic of Belarus for a useful model were issued, with twenty-five designs being applied in practice.

Instrument Engineering

Elaboration, design and reconstruction of some instruments and installations were performed in the laboratory:

  • installation for recording and quantifying leaf phytochrome in vivo was designed based on spectrophotometer modification;
  • installation for studying reversible phytochrome phototransformation;
  • laboratory specimen of photobiosensor based on Clark oxygen electrode;
  • attachment to spectrophotometer for specimen cross-illumination;
  • computer installation for measuring aequorine chemiluminescence enabling recording of intracellular calcium ion concentration in studying the role of secondary mediators in the transduction chain of light and phytohormonal signals in cell;
  • installation for semi-automatic measurement of enzyme activity;
  • attachment to spectrophotometer for gel scanning;
  • spectrophotometer computerization for quantifying plant pigments;
  • stirring installations for microorganism growing.

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