Nature of the effect on RNA and substrate specificity of RNAase of Bacillus amylozyma 9a]

Extracellular RNAase from Bac. amylozyma 9a has endonucleolytic character of the action on RNA, it splits in RNA 5'-phosphodiester bonds of GpXp type (where X is any nucleoside). The hydrolysis proceeds in two steps by the intramolecular transphosphorylation type of reaction to form guanosine-2',3'-phosphates and with the subsequent hydrolysis of cyclic bonds. The enzyme shows a preferable specificity to the single-stranded structure of the polyribonucleotides.     

Spontaneous fluctuations in the activity of rabbit skeletal muscle NAD-kinase]

Spontaneous fluctuations in the time of the activity of the 280-300-fold purified NAD-kinase preparation from rabbit skeletal muscle following its dilution are described. Defrosted but undiluted enzyme preparation failed to exhibit any fluctuations in its activity.     

Autonomic components of voluntary responses in children of different ages]

The formation of a complex of vegetative-somatic components of constructive activity (assembling figures out of mosaic chips) was analysed in children in the ontogenetic aspect during elaboration of a dynamic stereotype to direct stimuli (with presentation of samples) and during instantaneous formation of voluntary reactions to stimuli of a mainly second signal nature (without presentation of samples). The complex of effector vegetative-somatic components became more complicate and elaborate in the course of the child's growth, beginning with areflexia and disintegration in children of the younger groups (aged from two to three years) and up to correlated synchronous reflex changes of these components in children of the older group (six to seven years old).     

The effect of locus ecs in Drosophila melanogaster on fertility of females

A total of 13 ecs mutations affecting female fertility were isolated by complementation analysis. Seven of them were rearrangements with the br complementation group phenotype. Six other mutations had no cytologically detectable rearrangements and behaved as completely or partially non-complementing alleles of the ecs locus. All viable combinations of the above 13 mutations disturbed female fertility. Sterile were all fully viable compounds carrying any of these mutations and rearrangements Df (1) sta, T(1; 3)sta, Df(1)St490, previously localized on the molecular map distally to the ecs locus. According to data on location on molecular map of lesions affecting fertility, at least two elements at the ecs locus seem essential for this function: the most distal (left) cis-acting zone with no effect on viability and a sequence within the limits of the essential part of the ecs locus. Disturbance of any of these zones or their separation in the rearranged chromosomes lead to female sterility.     

Modeling dark puffs using P-transposons in Drosophila melanogaster polytene chromosomes

Modeling of morphologically unusual "dark" puffs was conducted using Drosophila melanogaster strains transformed by construct P[ry; Prat:bw], in which gene brown is controlled by the promoter of the housekeeping gene Prat. In polytene chromosomes, insertions of this type were shown to form structures that are morphologically similar to small puffs. By contrast, the Broad-Complex (Br-C) locus, which normally produce a dark puff in the 2B region of the X chromosome, forms a typical light-colored puffs when transferred to the 99B region of chromosome 3R using P[hs-BRC-z1]. A comparison of transposon-induced puffs with those appearing during normal development indicates that these puff types are formed via two different mechanisms. One mechanism involves decompaction of weakly transcribed bands and is characteristic of small puffs. The other mechanism is associated with contacts between bands adjacent to the puffing zone, which leads to mixing of inactive condensed and actively transcribed decondensed material and forming of large dark puffs.     

Morphogenetic effects of the interaction of floral mutations petal-sepal and anther in petal in Papaver somniferum l

The morphogenetic effects of the interaction of the floral mutations petal-sepal and anther in petal in Papaver somniferum L. with a monocarpic shoot were studied. During analysis of the mutations controlled by the genes ptsp and Ant, no plants of the double-mutant class were found in the second generation, in which microsporangia form on the corolla sepal structures. The ratio of phenotypic classes obtained in the experiment corresponds to that inheritance, when the genetic control of mutant characters is realized by nonallele nonlinked genes Ant and ptsp upon epistatic interaction of these genes. These data were confirmed by analysis of the genotypes of F2 plants from the phenotypic class petal-sepal, which include plants that carry both mutant genes Ant and ptsp. The results obtained suggest that the gene Ant, which controls the formation of microsporangia in the corolla metameres, is not expressed in the presence of a mutation of the gene ptsp; i.e., microsporangia are not formed in tissues with photosynthesizing cells. It is evident that the development of microsporangia is determined by the level of a product of the gene Ptsp. The role of flavonols (quercetin), inhibitors of photosynthesis, as a mechanism of regulation of activity of the genes controlling morphogenesis of the corolla elements and differentiation of microsporangia, is discussed.     

Heterochromatin,gene position effect and gene silencing

Genomes of higher eukaryotes consist of two types of chromatin: euchromatin and heterochromatin. Heterochromatin is densely packed material typically localized in telomeric and pericentric chromosome regions. Euchromatin transferred by chromosome rearrangements in the vicinity of heterochromatin is inactivated and acquires morphological properties of heterochromatin in the case of position effect variegation. One of the X chromosomes in mammal females and all paternal chromosome set in coccides become heterochromatic. The heterochromatic elements of the genome exhibit similar structural properties: genetic inactivation, compaction, late DNA replication at the S stage, and underrepresentation in somatic cells. The genetic inactivation and heterochromatin assembly are underlain by a specific genetic mechanism, silencing, which includes DNA methylation and posttranslational histone modification provided by the complex of nonhistone proteins. The state of silencing is inherited in cell generations. The same molecular mechanisms of silencing shared by all types of heterochromatic regions, be it unique or highly repetitive sequences, suggest the similar organization of these regions. No type of heterochromatin is a permanent structure as they all are formed at the strictly definite stages of early embryogenesis. Based on the bulk of evidence accumulated today, heterochromatin can be regarded as a morphological manifestation of genetic silencing.     

Correlation between family and age of manifestation of lung and colon cancer

The probability to develop lung cancer before 80 years of age is 1.67 and 0.18% for the male and female populations of Kharkov, respectively; the probability to develop large-intestine cancer is 0.92 and 0.49%, respectively. The correlation coefficient (r) of the age of manifestation (AM) of cancer in parent-offspring pairs is 0.47. These correlation coefficients for the father-son, mother-daughter, mother-son, and father-daughter pairs are 0.64, 0.49, 0.44, and 0.37, respectively. If the parent has lung cancer, the correlation is stronger (r = 0.71). On average, cancer is manifested in offspring earlier than in parents (57 and 63 years, respectively); the differences in the father-daughter and mother-son pairs are 8.2 and 2.8 years, respectively. The best prognostic parameter is the AM of cancer in the father with respect to the AM in the son (byx = 0.45).