Page 95 - Zbornik_Konf_2019

https://doi.org/10.15414/2019.9788055220703

4 International Scientific Conference Abstracts Book
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BIOLOGICAL ACTIVITY OF DIOSPYROS KAKI THUNB. LECTIN

Iryna Karpova, Larisa Palchykovska, Valentyna Lylo
Institute of Molecular Biology and Genetics of the National Academy of Sciences of Ukraine, Kyiv,
Ukraine; E-mail.: karpovair79@gmail.com
Persimmon – Diospyros kaki Thunb. (Ebenaceae) is a dietary and medicinal plant used in
alternative medicine of the peoples of the East. Tea made from dried persimmon leaves is
consumed in Japan and Korea. It has been shown that the components of the extract of
persimmon leaves exhibit antioxidant activity, antitumor effects, regulate the activity of the
angiotensin-converting enzyme (ACE), reduce the manifestation of allergy symptoms, etc.
In our previous work, the sialospecific lectin from sepals separated from ripe
persimmon fruits was first obtained. Interest in lectins – carbohydrate-binding proteins is
constantly growing due to their antiviral, antibacterial and antitumor properties. The lectin
was shown to induce the expression of interferon-alpha (IFNα) gene and some of its target
genes in rat liver. This could be the indirect manifestation of the antiviral potential of the
lectin.
Subsequent studies have revealed the antiviral activity of persimmon lectin against HIV,
herpes type 1 and type 2, and influenza A/FM/1/47/H1N1/ in mammalian cell culture in
vitro.
The aim of the study presented was to determine other targets sensitive to the lectin
action. To study the ability of D. kaki lectin do effect on RNA synthesis in vitro the model
transcriptional system that included bacteriophage T7 polymerase (T7RNAP) as described in
(Palchikovska et al., 2005) and linear DNA of pTZ19R* plasmid as a template was used.
Persimmon lectin was isolated by the modified procedure of isoelectric focusing followed by
ammonium sulfate fractionation. Hemagglutinating activity of the lectin (GAA) was estimated
visually in serial two-fold dilutions in microtiter plates followed by adding of 2 % suspension
of native human or formalin-fixed sheep erythrocytes. It was presented by logarithm (log2) of
the last lectin dilution where GAA was observed. Lectin preparations were characterized by
SDS-PAGE according to Laemmli method.
Using the method of isoelectric focusing, which allows separating different isoforms of
the protein, it was shown that the major lectin from persimmon sepals in the presence of
beta-mercaptoethanol forms one protein zone in SDS-PAGE, which corresponds to ml. mass of
about 30 kDa. From this, it followed that this protein consists of at least two identical
subunits. Our studies focused on elucidation the cell targets sensitive for the persimmon lectin
demonstrated the evident effect on RNA synthesis in vitro catalyzing by T7 RNAP. The lectin of
D. kaki in the transcription assay showed concentration-dependent inhibitory activity in the
range of 1.5–25.0 μg/ml, where concentrations 12.5 and 25.0 μg/ml completely inhibited the
RNA synthesis. According to the results obtained, we suppose that at least one of the lectin
targets may be the DNA-dependent synthesis of RNA – the way to activate/inactivate gene
expression.
Keywords: Diospyros kaki sepals, lectin, DNA-dependent synthesis of RNA.

4 International Scientific Conference Agrobiodiversity Nutrition, Health and Quality of Human and Bees Life |95
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September 11–13, 2019