The Database for Analysis of Quantitative Characteristics of Chromosome Aberration Frequencies in the Culture of Human Peripheral Blood Lymphocytes

The data on spontaneous chromosome aberration rates in cultures of human peripheral blood lymphocytes obtained in the past 30 years have been collected to form a database. The database contains the results of analysis of more than 330 000 metaphases in lymphocytes from more than 1200 subjects. The frequency of aberrant metaphases in the control group has been estimated at 0.0213 ± 0.00085. No differences between sexes have been found with respect to either the total chromosome aberration rate or the rates of individual aberration types. The total chromosome aberration rate did not depend on age; however, it has been found that the number of fragments increased and the number of exchanges decreased with age. Smoking has been found to increase the frequency of chromosome aberrations in individuals with occupational hazards, but not in those who are not occupationally exposed to radiation or chemicals. Alcohol consumption increased the frequency of paired fragments, whereas the frequencies of other aberrations did not differ from the control values.     

Effect of melafen on the function of endoplasmic reticulum and plasmalemmal H+ -ATPase in the regulation of growth processes in potato tubers

The mechanism of the stimulatory effect of melafen on potato tuber sprouting was studied. The treatment with 10(-8) M melafen intensified division and stretching and activated granular endoplasmic reticulum of apical meristem cells. An increase in the activity of membrane-bound H+-ATPase in the plasmalemma of parenchymal cells of melafen-treated potato tubers and enhancement of passive proton permeability of the plasmalemma was observed. In vitro studies showed that melafen at concentrations of 10(-5-10-12) M stimulated the activity of plasmalemmal H+-ATPase in a concentration-dependent manner.     

Ultramorphometric study of the plastids in apical tuber cells of original and transgenic potato plants treated with ambiol

Ultramorphometric characteristics of plastids in cells of apical tuber meristems of original and defensin gene-transfected potato (Solanum tuberosum L.) plants, either maintained under normal conditions or subjected to treatment with the antioxidant ambiol, were compared. Under normal conditions, the tuber cells of the original and transgenic potato plants differed in neither the number nor size of the plastids. Only certain quantitative distinctions in the development of individual ultrastructural characteristics of plastids were detected. Treatment with ambiol enhanced the differentiation of the internal membrane system of plastids in the cells of original and transgenic plants, especially the tubular membrane systems. Certain differences in the responses to ambiol of cell plastids of original and transgenic plants were related to plastid sizes and development of individual intraplastid structures. The results comply with earlier data on varying responses of mitochondria of original and transgenic plants to ambiol treatment.     

Morphogenetic changes in ambiol-treated regenerates of parent and transgenic potato plants

The effects of ambiol, a new growth regulator, on the formation of leaves and roots in parent and defensin gene-transformed regenerants of potato Solanum tuberosum L. (cultivar Desire). Various concentrations of ambiol induced differences in morphogenetic parameters between parent and transgenic plants. In some cases, ambiol caused the formation of shoots without leaves or with rudimentary leaves. The data suggest that features of root and leaves formation in parent and transgenic regenerants induced by ambiol are due to changes in hormone balance in transgenic plants caused by expression of the defensin gene and the effect of ambiol on the plant hormonal balance.     

Effect of ambiol on stem growth in regenerants of source and transgenic potato plants

The effects of ambiol, a new growth regulator, on stem growth and morphological features of stem development have been compared in regenerants of potato (Solanum tuberosum L., var. Desire) plants transgenic for a defensin gene and in original potato plants. The original and transgenic plants exhibited differences in shoot development, which were observed both in control settings (no ambiol) and in the presence of various ambiol concentrations. In addition to normal plants of both forms, plant regenerants with morphological deviations were present in ambiol-treated groups. It is suggested that the abnormal shoot development observed in original and transgenic potato plants treated with ambiol is associated with (a) hormonal changes caused by expression of the defensin gene in the transgenic plants and (b) effects of ambiol on the hormonal balance of the plants.     

Hyperoxic vasoconstriction in the brain is realized by inactivation of nitric oxide by superoxide anions

We tested a hypothesis that the cerebral blood flow (CBF) is reduced at hyperbaric oxygen due to inactivation of nitric oxide (NO) by superoxide anions (O2). In our experiments, the CBF was measured under hyperbaric oxygenation (HBO) 4ATA after inhibition of NO synthesis and inactivation of O2. The CBF was reduced at HBO exposure. Inhibition of NO--synthase type I and III (NOS) by L-NAME in the air caused the same decreasing of the CBF as at 4 ATA HBO. Hyperbaric vasoconstriction was diminished after NOS inhibition. Intravenous injection of superoxide dismutase (CuZn SOD) increased the CBF in the air and HBO exposure. This effect disappeared at preliminary NOS inhibition. These data suggest that inactivation of NO by O2 is a more effective mechanism of HBO vasoconstriction.     

Age-Related Features of Ceruloplasmin Biosynthesis and Distribution in Rats

In vivo biosynthesis of ceruloplasmin (Cp), a copper-containing glycoprotein, which plays an important role in copper transfer between organs and bidirectional iron transport in vertebrates, was studied in 7-day old rats, which are characterized by the embryonic type of copper metabolism. In addition to the liver, Cp is synthesized in the lungs, brain, and kidneys. In pulse-chase experiments it was demonstrated that [¹⁴C]-Cp appearance in the blood coincides with the secretion ofde novo synthesized Cp from the liver. [¹⁴C]-Cp is taken up from the blood stream by cells of the heart, lung, and kidneys and binds to red blood cells, while Cp polypeptide chain is not taken up by the brain cells. Immunoreactive polypeptides of the Cp receptor were found using immunoblotting in plasma membranes of the heart, liver, kidneys, and red blood cells, rather than in the brain. Using the RT-PCR method with selective primers, it was shown that these cells contain molecular forms of Cp-mRNAs programming the synthesis of both secretory Cp and Cp bound to the plasma membrane via a glycosyl phosphatidylinositol anchor. After switching to the adult type of copper metabolism, the blood serum contents of copper and Cp sharply increase, while the Cp content in the cerebrospinal fluid, as measured according to the oxidase and antigen activities, and copper concentration, as determined by atomic absorption spectroscopy, remain low. Ontogenetic features of the system ensuring the copper homeostasis in mammals are discussed.     

Temperature-Induced Inactivation of Cytoplasmic Biogel Osmosensing Properties is Associated with Suppression of Regulatory Volume Decrease in A549 Cells

Upstream intermediates of intracellular signaling involved in cell volume regulation remain poorly explored. Recently, we demonstrated that osmolarity-induced volume changes in permeabilized cells were several-fold higher than those observed with intact cells, indicating the osmosensing properties of cytoplasmic gel. To further examine the role of cytoplasmic biogel in cell volume regulation, we compared the action of short-term heat treatment on volume changes in intact and permeabilized A549 cells. Pretreatment of A549 cells at 48 °C suppressed swelling triggered by dissipation of Donnan’s equilibrium as well as by hyposmotic medium. Significantly, heat treatment completely abolished the action of hyposomotic medium on volume changes in permeabilized cells, showing that temperature elevation suppresses osmosensing properties via its effect on biogel rather than on plasma membrane water permeability. Identical heat treatment blocked the regulatory volume decrease (RVD) as well as the increment of Ba²⁺-sensitive K⁺-channel activity seen in control cells exposed to hyposmotic swelling. Unlike swelling, hyperosmotic shrinkage was decreased by twofold in cells subjected to 10-min preincubation at 50 °C. Our results disclose that osmosensing by cytoplasmic gel is a key event in the RVD triggered by hypotonic swelling. The role of biogel and plasma membrane in intracellular signaling triggered by hyperosmotic shrinkage should be further investigated.