Control of meiotic crossing over in plant breeding.

Meiotic crossing over is the main mechanism for constructing a new allelic composition of individual chromosomes and is necessary for the proper distribution of homologous chromosomes between gametes. The parameters of meiotic crossing over that have developed in the course of evolution are determined by natural selection and do not fully suit the tasks of selective breeding research. This review summarizes the results of experimental studies aimed at increasing the frequency of crossovers and redistributing their positions along chromosomes using genetic manipulations at different stages of meiotic recombination.

Effective RNAi-Mediated Silencing of the Gene Induces Sterility of Tomato Plants but Not an Increase in Meiotic Recombination.

In plant breeding, the ability to manipulate meiotic recombination aids in the efficient construction of new allelic compositions of chromosomes and facilitates gene transfer from wild relatives of crop plants. The DNA mismatch repair system antagonizes meiotic recombination. In this research, a trial was conducted to evaluate transgenic tomato plants carrying an RNA interference (RNAi) construct designed to inhibit the expression of the mismatch repair gene.

A Synthetic Strong and Constitutive Promoter Derived from the pro-SmAMP1 and pro-SmAMP2 Promoters for Effective Transgene Expression in Plants.

Synthetic promoters are vital for genetic engineering-based strategies for crop improvement, but effective methodologies for their creation and systematic testing are lacking. We report here on the comparative analysis of the promoters pro-SmAMP1 and pro-SmAMP2 from () and (). These promoters are more effective than the well-known 35S promoter.

Novel strong promoter of antimicrobial peptides gene pro-SmAMP2 from chickweed (Stellaria media).

Background: In a previous study we found that in chickweed the expression level of the pro-SmAMP2 gene was comparable or even higher to that of the β-actin gene. This high level of the gene expression has attracted our attention as an opportunity for the identification of novel strong promoters of plant origin, which could find its application in plant biotechnology. Therefore, in the present study we focused on the nucleotide sequence identification and the functional characteristics of the pro-SmAMP2 promoter in transgenic plants.

[Spatiotemporal characteristics, of the heart electrical field at the period of ventricular depolarization in athletes training endurance and strength].

As a result of haemodynamic and structural changes occurring in athletes' heart under the influence of systematic physical loads, myocardial electrical activity changes that is reflected on the electric field being formed on the body surface. The heart electrical activity during ventricular depolarization at rest has been investigated in the highly skilled athletes who train to develop physical characteristics--endurance and strength by a method of electrocardiotopography. In the investigated sportsmen under uniformity of the character of the movement of positive and negative cardioelectric potential zones and localization of extrema, and general depolarization duration, the significant distinctions of: 1) amplitude of the maximum negative extremum, 2) the time of the beginning and end of the first inversion, 3) duration of the second inversion, the initial stage and the stability period between inversions, 4) the relative location of the zones of positive and negative cardiopotentials were revealed.

[Heart electric activity during ventricular repolarization of sportsmen-swimmers at physical workload].

The research of heart electrical activity of sportsmen-swimmers has been carried out using a functional test with physical activity. Standard 12-lead electrocardiograms and the cardioelectric field on the athletes' thorax surface were analyzed at rest and in every minute of a five-minute recovery period after submaximal workload. The changes of amplitude-temporal characteristics of the heart electric field on the athletes' body surface were revealed while performing physical workload.

Down-regulation of the tumor suppressor gene C-terminal Src kinase: an early event during premalignant colonic epithelial hyperproliferation.

Hyperproliferation of the premalignant epithelium is critical for colonic carcinogenesis; however the mechanisms remain largely unexplored. We report herein that prior to occurrence of neoplastic lesions in the azoxymethane-rat model of colon carcinogenesis; the tumor suppressor gene C-terminal Src kinase (Csk) was down-regulated with a concomitant increase in Src activity. Furthermore, pharmacological or genetic (RNA interference) inhibition of Csk resulted in increased proliferation in colon cancer cell lines through the mitogen-activated protein kinase dependent pathway.