Independence of the processes of transposition and genome rearrangements induced by transposons

The data on the influence of the tnm mutations affecting transposition process on the deletion formation promoted by Tn and IS elements are presented. It was shown that the tnm mutations did not affect the frequency of deletion formation. The results of genetic analysis of the tnm mutant deficient in both transposition and genomic rearrangements induced by Tn9 inserted into lambda prophage, indicated that the mutant phenotype was caused by two different but linked mutations. A mutation affecting the process of genomic rearrangements was designated gerA2. The gerA2 mutation decreased sharply the frequency of rearrangements promoted by Tn9, Tn10 or Tn601 inserted into lambda prophage. However, this mutation had no influence upon transposition of the same Tn elements. The data obtained could be interpreted as indicating the independence of the processes of transposition and genomic rearrangements or as indication of the existence of specific steps of these processes.     

Changes in ornithine decarboxylase activity in the developing parotid salivary gland

Ornithine decarboxylase activity in the rat parotid salivary gland was estimated during the early postnatal development. Regular alterations of enzymatic activity were found in different periods of gland development. The data obtained were compared with the evidence on the establishment of protein synthesis circahoralian rhythm of this organ in ontogenesis. The ornithine decarboxylase activity, being rather high in the parotid gland as long as up to the 20th-21st days, decreases during the termination of differentiation in this organ. It rises simultaneously with the emergence of circahoralian rhythm of protein synthesis.     

Isolation and various properties of soluble and membrane-bound acid RNAse from rat brain lysosomes

Preparations of soluble (I) and membrane-bound (II) acid RNAse with Mr 68,000 and 72,000 Da, respectively, and purified about 2000-fold were isolated from lysosome-rich fractions of rat brain large hemispheres. RNAase II differed from RNAase I by a lower temperature stability. The pH optimum (pH 5.8-6.1), temperature optimum and substrate specificity of RNAase I and II appeared to be identical. The Km values of RNAases I and II for poly(U) are 166 and 160 micrograms/ml; those for RNA--1200 and 1250 mu k/ml, respectively. RNAases I and II extensively hydrolyze soluble, polymeric RNA, rRNA from brain and yeast and poly(U) but do not influence poly(C), poly(A), poly(G), tRNA and DNA. Monovalent cations (K+, Na+, NH4+) activate both RNAase forms.     

Amplitude-time characteristics of the long-latency components (<Emphasis Type="Italic">N</Emphasis>1, <Emphasis Type="Italic">N</Emphasis>2, and <Emphasis Type="Italic">P</Emphasis>300) of acoustic evoked potential in healthy subjects

The aim of the study was to trace the cumulative changes in the amplitude-time parameters of the AEP (acoustic evoked potential) components N1, N2, and P300 in the experimental situations of different complexities (counting and listening to sounds) and to compare the differences between young and mature subjects. The AEP was recorded in 12 healthy subjects aged 18 to 22 years and in 12 subjects aged 32 to 59 years. It was revealed that the components N1, N2, and P300 recorded in the situation of listening without any preliminary instruction did not differ in young and mature individuals. In the younger subjects, a higher N1 amplitude was revealed when they counted sounds, compared to listening, whereas the latency values of this component did not differ, irrespective of the complexity of the task. The component N2 was shown to demonstrate latency stability in relation to the age and the experimental situation. The N2 amplitude was higher in the situation of counting sounds in both age groups. The amplitude-time parameters of P300 did not differ in subjects of different ages in the listening task. The features of the components N1, N2, and P300 revealed in young and mature subjects in the experimental situations differing in complexity lead us to suggest that, with age, humans develop adaptive mechanisms contributing to successful task performance.     

Changes in the intensity of protein synthesis in the gastric mucosa following the laser irradiation of a duodenal ulcer]

The intensity of protein synthesis (incorporation/pool) is usually low in normal stomach mucosa and enhanced in exacerbation of peptic ulcer; following the effective laser therapy it decreases only in one third of cases. Therefore the scarring of ulcer not always coincides with the normalization of protein synthesis. The results characterize also the community of reactions in stomach and duodenal mucose membranes. The changes in protein synthesis intensity following the laser irradiation depended neither on the initial size of ulcer nor on the age of patient and the total duration of disease.