[Callose accumulation during treatment of tomato (Lycopersicon esculentum L.) cells with biotic elicitors].

Time-course of induced accumulation of callose in tomato cells has been studied. Localization of callose in L. esculenthum cells was investigated by fluorescent microscopy technique, and the optimal time for its determination was found. Callose accumulation in tomato cells treated with different biotic elicitors was determined. Nonlinear dependence between callose accumulation and concentration of chitin oligomers (with 3-5 N-acetylglucosamine fragments) was established. Increasing of callose accumulation in tomato cells was proportional to the increase of concentration ofchitin dimer and chitosan in the culture medium.

[Mechanisms of action of plant resistance inductor beta-aminobutyric acid in Allium cepa].

The effects of beta-aminobutiric acid as an inductor of plant resistance was studied. The influence of BABA pretreatment on A. cepa plants of three different pathogen-resistant varieties was investigated by fluorescence microscopic methods. It was determined that BABA is able to prime the plant callose accumulation.

[Reactive oxygen species and plant immunity].

Reactive oxygen species (ROS) play a key role in plant defense mechanisms. They exert direct antimicrobial action, catalyze the mechanical strengthening of cell walls, function as secondary messengers in the superoxide synthase signal pathway and in triggering the hypersensitive response. Although recent studies have unraveled a nature and the mechanisms of the oxidative burst, many questions related to its mode of regulation, its modulation of signaling networks that control growth, development and defense responses remain unanswered.

The congenital anomalies registry in Belarus: a tool for assessing the public health impact of the Chernobyl accident.

A national population-based malformation registry (BNR) has been in operation since 1979 in Belarus, one of the countries most heavily exposed to the contamination from the Chernobyl accident of 26 April 1986. We describe its methodology and its compliance with established criteria, evaluate the completeness of its reporting, and analyze the data collected in four administrative regions with contrasting contamination levels from 1983 through 1999. Nine easily diagnosed malformations have been monitored since 1983. Reporting completeness exceeds 85% for all periods and all regions. In all periods, the prevalence at birth of these malformations was lower in the most contaminated regions and showed a similar positive time trend in areas of low and high contamination. We conclude that the BNR is a reliable tool for studying the possible effects on congenital malformations caused by the Chernobyl accident. Although the trend we observed may be explained by better ascertainment and prenatal diagnosis, a real increase cannot be ruled out.

[Role of active forms of oxygen in the induction of phytoalexin synthesis in Allium cepa cells]. / Rol' aktivnykh form kysniu v induktsiï syntezu fitoaleksyniv u klitynakh Allium cepa.

The results of studies on the role of plant superoxidesynthase signal system in elicitation of antimicrobial phytoalexin (PA) synthesis in cultured Allium cepa cells are presented. Exogenic application of O2- and H2O2 generators results in formation of PA--Tcibulins 1D and 2 [symbol: see text] in A. cepa cells. The mechanism of PA elicitation does not require peroxidase activity. However, the inhibition of one of the possible sources of the reactive oxygen, HADPH oxidase, suppresses elicitor-stimulated PA production. "Oxidative burst" modulation by different chemical compounds in A. cepa cells results in changes of PA synthesis elicitation. The results obtained suggest the tough correlation between "oxidative burst" and elicitation of defense responses, PA synthesis in particular.

[Down syndrome and ionizing radiation: causal effect or coincidence]. / Sindrom Dauna i ioniziruiushchaia radiatsiia: prichinno-sledstvennaia sviaz' ili sluchainaia zavisimost'.

Annual and monthly prevalence of Down's Syndrome has been analyzed in Belarus for a 19-year period (1981 to 1999). The distribution of 2786 DS cases during this period showed no significant long-term prevalence trend. Meanwhile, 2 marked increases of DS prevalence were registered in 1987 and 1990. The most remarkable annual increases were observed in 1987 in Minsk city, in Vitebsk oblast (considered as contamination-free administrative district) and in Minsk oblast (partially contaminated area), data not shown in the text. Much more marked and significant increases were recorded in January 1987, in Minsk city, Gomel oblast and Minsk oblast. However it is impossible to establish a causal relationship between these clusters of DS and exposure to the Chernobyl fallout, at a geographical level. The presence of such a cluster 9 months after the explosion in one of the most exposed area (Gomel oblast) should incite to careful conclusions and prompt further studies.

[Induction of active forms of oxygen by biotic elicitors in tomato cell cultures]. / Induktsiia aktivnykh form kisloroda bioticheskimi élisitorami v kul'ture kletok tomatov.

The elicitor-induced generation of two oxygen species in tomato cell culture as well as their involvement into hypersensitive reaction was investigated. Generation of superoxide O2.- was measured by a lucigenin-related chemiluminescence. Accumulation of hydrogen peroxide H2O2 was measured by a fluorescent probe pyranin. Xylanase and chitosan were used as biotic elicitors with different mode of action. It was found that both O2.- and H2O2 had been accumulated in elicitor-treated tomato cells. The results obtained show that reactive oxidants are important signal transduction elements for activation of hypersensitive response in tomato cells.

[Local preventive antibacterial therapy with polymer biocompatible combination]. / Polimernaia biosovmestimaia kombinatsiia dlia mestnoi profilakticheskoi antibakterialnoi terapii.

The paper provides data on the properties of the powdery antimicrobial absorbent Ambipor and the procedure of its use in the prevention of postoperative suppuration, which consists in application of the powder to the wound surface with a broken layer just before wound suture. It shows that a single application of Ambipor to wound suture. It shows that a single application of Ambipor to wound tissues at the end of an operation ensures high paravulnar tissue antibiotic concentrations which are many times higher those used in conventional antibacterial therapy. Implantation of Ambipor to operative wound tissue at the end of an operation aids to reduce the extent microbial dissemination by more than 100-1000 times, to accelerate reparative processes, stimulate early fibroplast activation, fibrillogenesis, scarring tissue maturation. Topical antibacterial therapy with the developed formulations is an effective tool in preventing postoperative wound complications. Its application to clinical practice enables the incidence of complications to be decreased by more than 4.5 times higher than those in the controls.