Vol 52, No 6 (2018)

High-performance liquid chromatography–mass spectrometry has been used to study the character of the accumulation and balance of endogenous indolyl-3-acetic (IAA) and abscisic (ABA) acids in the “hairy” roots of Artemisia vulgaris obtained by transformation with Agrobacterium rhizogenes agropine strain A4. The free IAA content was significantly higher than the level of the conjugated form of the hormone. The highest amount of the active IAA form (554.4 ± 27.7 ng/g fresh weight) was detected in line no. 2. The free form of ABA predominated in the roots of control samples, where its level was significantly higher than in the transformed lines. The “hairy” roots accumulated a conjugated form of ABA, and the highest content of this compound amounted to 459.6 ± 23.0 ng/g of fresh weight (in line no. 4). The architecture of the transformed roots was marked by significant branching and lateral root formation; active accumulation of biomass was detected. The results obtained demonstrate changes in the endogenous phytohormone balance in the “hairy” A. vulgaris roots, namely, a trend to predomination of the free IAA form and a significant decrease of the ABA content.

The emergence of genomics and its use in combination with high-resolution bioimaging for the study of animal development mechanisms provide scientists with information on gene sets and regulation thereof during development. This enabled the identification of the core set of transcription factors involved in the development of invertebrates and vertebrates. This approach was particularly efficient due to the widespread use of transparent embryos of zebrafish and other bony fishes in these studies. These embryos can be used as model systems for the analysis of vertebrate development, even at the level of individual cells, as the various processes of development unfold in vivo.

Analysis of 11 diploid-polyploid samples of spined loaches of the genus Cobitis from the aquatic systems of Ukraine showed that the increase in the number of micronuclei in red blood cells positively correlates with the ploidy and cell size. In diploid individuals of parental species, micronuclei cells average 0.12%, whereas they average 0.52, 1.39, and 4.72% in hybrid triploids, tetraploids, and probable pentaploids, respectively. Since triploid and tetraploid specimens in joint colonies tend to prevail over diploid ones, it can be concluded that minor disturbances in the genetic apparatus do not significantly affect the fitness, whereas an increase in the number of chromosomal sets over four is already accompanied by dysfunctions critical to normal life activity. Apparently, it is this circumstance that has led to the absence or extreme rarity of the pentaploid states in the clonal vertebrates, whereas penta-, hexa-, octo-, and even decaploid states are common in the lower invertebrates, for example earthworms. The latter is probably due to the fact that the minimum size of the genome in earthworms is several times smaller than in teleosts, which allows lower invertebrates to increase the number of chromosomal sets by more than fourfold.

A population of F₆ recombinant inbred lines from the cross between winter common wheat lines with the wheat-rye translocations 1BL.1RS (of the Kavkaz type) and 1АL.1RS (of the Amigo type), B-16 × 7086 AR, was produced. Using the storage protein loci Gli-R1, Gli-A1, and Gli-B1 as genetic markers, lines with recombinant 1RS (12%) were identified and the frequency of recombination between 1RS involved in different translocations was determined as 7%. 1RS from Amigo was demonstrated to carry a gene encoding the secalin “a”, which can be identified on SDS electrophoregrams under the y-subunit encoded by the Glu-D1 locus. The secalin “a” was also revealed in the cultivar MV Táltos, which was shown to carry the 1BL.1RS translocation with secalin alleles of the Amigo type. The gene encoding the secalin “a” was found to be allelic to the gene Sec-Nx from the rye Voronezhske SGI. The frequency of recombination between the loci Gli-R1 and Sec-N depends on the nature of the material analyzed and amounts about 10% (the genetic distance of 10 cM) in the cross MV Táltos × CWX (the lines with different 1BL.1RS translocations). Such a distance suggests that important disease and pest resistance genes, in particular stem rust resistance genes, are within the region flanked by these loci. Because of this the secalin loci are convenient for primary screening for recombinant 1RS arms with new combinations of disease and pest resistance genes.

The frequency of spontaneous and X-ray-induced (0.25 Gy) in vitro chromosomal aberrations, as well as the level of chromosomal instability as a result of the bystander effect, in the blood lymphocytes of individuals aged from 12 to 102 years has been investigated using GTG staining of human metaphase chromosomes. The average group frequency of spontaneous chromosomal aberrations in adolescents (12–16 years), middle-aged people (33–52 years), and centenarians (90–102 years) was identical (p > 0.05), whereas it was higher in elderly people (60–70 years) due to increase of chromatid type aberrations rate (p < 0.05). In the irradiated in vitro blood lymphocytes of individuals aged 12–16 years, 33–52 years, and 90–102 years, the levels of chromosomal aberrations was not different (p > 0.05); however, the total frequency of chromosomal aberrations in individuals aged 60–70 years exceeded the value of such indices in other age groups due to the chromosomal type damages (p < 0.05). In nonirradiated blood lymphocytes of adolescents, middle-aged, and elderly individuals cocultivated with lymphocytes irradiated in vitro (0.25 Gy), the induction of the bystander effect was detected. In lymphocytes of centenarians, the development of the bystander effect was not detected.

Cytogenetical assessment of pollen mother cells of Guar (Cyamopsis tetragonoloba (L.) Taub.) in response to treatment of chemical mutagen was done. Ethyl Methane Sulphonate (EMS) revealed possession of an enigmatic behaviour among chromosomal bivalents i.e. formation of secondary association. Chromosomes exhibited a unique tendency of getting associated in close proximity and form discrete pairs. The phenomenon of secondary chromosomal association has been ascribed to the existence of similar cohesive homology or malfunctioning in chiasma formation among the associating bivalents. The association of bivalents was witnessed to be executed in either end to end fashion or sideways association. Various other chromosomal abnormalities were found, but secondary association was the preponderant abnormality which exhibited a continuous increase in its magnitude with increase in EMS concentration. Along with secondary associations, stickiness of chromosomes at anaphase was observed in considerable frequency. A significant influence of chromosomal association on the post meiotic product was also experienced, which in turn, led to influence the meiotic index. Abnormal sporads in the form of triads, dyads, monads and polyads, alongwith normal tetrad were seen. Pollen fertility percent was seen to decline from control to the highest concentration of EMS due to anomalies of preceding stages.