N6-(5-Phenylpentan-1-yl)adenine-A New Non-competitive Receptor-Specific Anti-cytokinin.

For the first time, N6-(5-phenylpentan-1-yl)adenine, a synthetic adenine derivative with a receptor-specific anticytokinin effect, was obtained. This compound exhibits a pronounced anticytokinin effect, reducing cytokinin-induced expression of the GUS reporter gene when interacting with the cytokinin receptor CRE1/AHK4 of the model plant Arabidopsis thaliana. This effect manifests itself much weaker with the related AHK2 receptor and is not observed at all with the AHK3 receptor. We showed that N6-(5-phenylpentan-1-yl)adenine does not bind to the ligand-binding sites of the Arabidopsis cytokinin receptors, which does not allow it to be classified as a true cytokinin antagonist. Despite the currently unknown mechanism of action, this compound may find its use as a component of plant growth regulators. Like true anticytokinins, it enhances root growth of Arabidopsis seedlings, apparently suppressing the action of endogenous cytokinins on the "root" receptor CRE1/AHK4.

Comparative Analysis of the Biosynthesis of Isoprenoid and Aromatic Cytokinins.

To compare the biosynthesis pathways of aromatic and isoprenoid cytokinins, a series of nucleoside derivatives of natural cytokinins was synthesized and their cytokinin activity was determined in a test system based on the model plant Arabidopsis thaliana. Cytokinin nucleosides are known to lack the hormonal activity until cleaving the ribose moiety at the position 9. Our experiments have shown that both ribo- and 5'-deoxyribo derivatives of N6-isopentenyladenine were able to turn into active cytokinins in planta exhibiting cytokinin activity. By contrast, 5'-deoxy nucleosides of aromatic cytokinins did not show similar activity. Since 5'-deoxy nucleosides cannot phosphorylate in vivo, the direct pathway of active cytokinin formation by cleavage of nucleotides is blocked here. The detected activity in 5'-deoxy nucleosides of isoprenoid cytokinins and the lack of the activity in 5'-deoxy nucleosides of aromatic cytokinins indicates the difference in the biosynthesis of these compounds.

Core features of the hormonal status in in vitro grown potato plants.

Some time ago, potato transformants expressing Agrobacterium-derived auxin synthesis gene tms1 were generated. These tms1-transgenic plants, showing enhanced productivity, were studied for their hormonal status, turnover and responses in comparison with control plants. For this purpose, contents of phytohormones belonging to six different classes (auxins, cytokinins, gibberellins, abscisic, jasmonic and salicylic acids) were determined by a sensitive UPLC-MS/MS method in tubers and shoots of in vitro grown plants. To date, this study represents the most comprehensive analysis of the potato hormonal system. On the basis of obtained results, several new generalizations concerning potato hormonal status were drawn. Overall, these data can serve as a framework for forthcoming integrative studies of the hormonal system in potato plants.

[Epigenetic mutagenesis as program of age-related protein dysfunction and aging].

DNA methylation plays an important polyfunctional role in ontogenesis of human and mammals. A steep rise in probability of mutational substitution of CpG dinucleotide on TpG dinucleotide in the genome is one of the consequences of DNA methylation. All spectrum (17) of possible DNA and protein mutations caused by CpG-dinucleotide methylation in DNA were characterized, and the three most dangerous mutations (able to result in protein inactivation) were isolated. The computer program that allows one to predict all most probable mutations in the analyzed gene and encoded protein was created. On the example of genes from humans and various mammals, it was demonstrated that the amount of potentially dangerous sites of epigenetic mutagenesis in exons was drastically decreased as a result of genome evolution. But, at the same time, unforced preservation of such sites and their persistence were established, indicating the occurrence of age-related protein dysfunction built into the genome epigenetic program, resulting in apoptosis and aging; this program is based on the set and position of methylated codons in exonic gene regions. It is assumed that the program of epigenetic mutagenesis limits the lifetime of an individual, accelerating the deliverance of the population from long-lived individuals that completed the reproductive period.

Receptor properties and features of cytokinin signaling.

Cytokinins belong to one of the most important and well-known classes of plant hormones. Discovered over half a century ago, cytokinins have retained the attention of researchers due to the variety of the effects they have on the growth and development of vegetable organisms, their participation in a plant adaptation to external conditions, and the potential to be used in biotechnology, agriculture, medicine and even cosmetics. The molecular mechanism by which cytokinins function remained unknown for a long time. Things started to change only in the 21(st)century, after the discovery of the receptors for these phytohormones. It appeared that plants found ways to adapt a two-component signal transduction system borrowed from prokaryotic organisms for cytokinin signalling. This review covers the recent advances in research of the molecular basis for the perception and transduction of the cytokinin signal. Emphasis is placed on cytokinin receptors, their domain and three-dimensional structures, subcellular localization, signalling activity, effect of mutations, ligand-binding properties, and phylogeny.

Molecular structure of phospholipase D and regulatory mechanisms of its activity in plant and animal cells.

Phospholipase D (PLD) catalyzes hydrolysis of phospholipids with production of phosphatidic acid, which often acts as secondary messenger of transduction of intracellular signals. This review summarizes data of leading laboratories on specific features of organization and regulation of PLD activity in plant and animal cells. The main structural domains of PLD (C2, PX, PH), the active site, and other functionally important parts of the enzyme are discussed. Regulatory mechanisms of PLD activity are characterized in detail. Studies associated with molecular design, analysis, and synthesis of new nontoxic substances capable of inhibiting different PLD isoenzymes in vivo are shown to be promising for biotechnology and medicine.

[Identification of genetically modified vegetable sources in food and feed using hydrogel oligonucleotide microchip].

A method of multiplex polymerase chain reaction (PCR) followed by the hybridization on a hydrogel oligonucleotide biochip was developed for simultaneous identification of ten different transgenic elements of plant DNA in feed and food products. The biochip contained 22 immobilized probes intended for (i) detection of plant DNA; (ii) plant species determination (soybean, maize, potato, rice); (iii) identification of transgenic elements, including 35S CaMV, 35S FMV, rice actine gene promoters, nos, 35S CaMV, ocs, pea rbcS1 gene terminators, and bar, gus, nptII marker genes. The limit of detection was 0.5% of genetically modified (GM) soybean and maize in analyzed samples. Identification of transgenic DNA in food and feed products using either the developed approach or real-time PCR led to virtually identical results. The assay can be used for selection of GM samples by screening food and feed products for subsequent quantitative determination of the GM component based on the identified transgene.

[Endoscopic assay and surgery at chronic pancreatitis]. / Endoskopicheskie issledovaniia i operatsii pri khronicheskom pankreatite.

OBJECTIVE: To assess the possibilities of endoscopic surgeries at the pathology of major duodenal papilla in patients with the painful form of chronic pancreatitis. The study involved 35 patients with the painful form of chronic pancreatitis including 19 subjects with cholecystectomy as a result of cholelithiasis, 8 subjects with alcohol-induced pancreatitis (4 of them had external pancreatic fistulas) and 8 patients with idiopathic pancreatitis. As many as 60 different X-ray and endoscopic procedures were carried out altogether: ERCPG, EPST and dissection of pancreatitis duct entrances as well as nasopancreatic drainage and stenting. ERCPG discovered the pathology of major duodenal papilla in the form of stenosis of the common bile duct entrance and/or main pancreatic duct entrance in 25 (71%) patients. At the same time, the ultrasonic examination discovered the pathology only in 7 patients (20%). EPST was performed in 20 patients of 25. The dissection of the major pancreatitis duct entrance was carried out in 16 of them; the dissection of the additional pancreatic duct was performed in 1 patient; the external pancreatic duct drainage was conducted in 5 patients; the additional pancreatic duct stenting was carried out in 1 patient. Fifteen patients (75%) felt better immediately upon the surgery. Ten patients were followed-up from 2 months to 3 years; steady amelioration was observed in 7 of them. There were complications in the form of acute pancreatitis in 3 patients after ERCPG and in 2 patients after endoscopic surgeries. There were no other complications or fatalities. For patients with the painful form of chronic pancreatitis, ERCPG is an informative and relatively safe technique enabling to discover the stenosis of the common bile duct entrance and/or main pancreatic duct entrance in 71% of cases. Endoscopic surgeries make it possible to produce an immediate positive result in 75% of cases.

Morphology and tuber formation of in-vitro-grown potato plants harboring the yeast invertase gene and/or the rolC gene.

Growth and tuber formation of transgenic potato plants (Solanum tuberosum cv. Désirée) harboring the yeast invertase gene and the rolC gene individually or in combination under the transcriptional control of the patatin promoter were investigated under different conditions in vitro. Plants expressing only the invertase gene were morphologically similar to control plants. rolC transgenic plants had an increased tiller number, improved root growth, and a higher total biomass. Tuber formation and growth were altered by the introduced transgenes. The sucrose requirement to induce tubers was shifted to lower or higher concentrations for invertase- or rolC-expressing clones, respectively. In addition, rolC plants formed tubers of altered morphology. A comparison with soil-grown plants showed that morphological parameters can be predicted to some extent from in vitro studies, while for reliable prescreening of parameters concerning tuber formation and growth, an optimization of currently used protocols is necessary.

[The morphometric and immunohistochemical indices of the gastric and duodenal mucosa in the dynamic treatment of erosive gastroduodenitis in those who worked in the cleanup of the aftermath of the accident at the Chernobyl Atomic Electric Power Station in the follow-up period]. / Morfometricheskie i immunogistokhimicheskie pokazateli slizistoi obolochki zheludka i dvenadtsatiperstnoi kishki v dinamike lecheniia érozivnogo gastroduodenita u likvidatorov posledstvii avarii na Chernobyl'skoi AES v otdalennom periode.

62 Chernobyl wreckers with erosive gastroduodenitis (50 cases) and ulcer (12 cases) were admitted to hospital where they received standard drugs and local He-Ne laser treatment of erosions and ulcer located in the antral stomach and duodenal bulb. Histological, bacterioscopic, morphometric and immunohistochemical examinations have identified chronic inflammation and disturbance of local immunity. After treatment epithelialization of erosions was not accompanied by normalization of morphometric and immunohistochemical parameters. This suggests a high risk of recurrences.

[The characteristics of gastroduodenal pathology in the workers of a plant for plastic construction materials]. / Osobennosti gastroduodenal'noi patologii u rabochikh zavoda stroitel'nykh plastikov.

Out of 162 workers exposed to chemicals in the manufacture of construction plastics an outpatient and inpatient examination revealed gastrointestinal problems in 84.3%, vegetative nervous disorders in 62.6% of the examinees. In a random sample of 47 workers high acid production occurred in 63.3% and erosions, ulcers, cicatrices in the stomach and duodenum in 45.2% of them. No HLA genetic predisposition to duodenal ulcer was reported. Histological findings on gastroduodenal mucosa biopsies were indicative of the dystrophy in the chief and lining cells of the gastric glands, epithelium and stroma with formation of the dark cells. The authors insist on consideration of the above facts in examination and treatment of workers exposed to chemicals at construction plastics plants.