Changes in the morphometric parameters of neuroblastoma cells cultured in a high pH medium

The development of a population of morphologically differentiated mouse neuroblastoma cells was investigated during culture in a medium with a pH of 8.0–8.2. The original population split into two subpopulations — one of proliferating and the other differentiating cells — on the third day of culture in modified medium. Changes in the morphometric parameters of cells differentiating with time was investigated in vivo. A significant correlation between somatic dimensions and neurite length was found in differentiating cells. This implies that degree of morphological differentiation may be determined by size of the soma when using this technique for inducing differentiation. The patterns noted may serve for further research into morphofunctional changes produced by induced differentiation of neuroblastoma cells.A. A. Bogomolets Institute of Physiology, Academy of Sciences of the Ukrainian SSR, Kiev. Translated from Neirofiziologiya, Vol. 20, No. 2, pp. 213–219, March–April, 1988.     

Detection of giant axospinal synapses in the hippocampus on semithin sections

A histological study of plastic semithin hippocampal sections after the treatment of myosin with tannic acid and detergent and then with subfragment-1 has shown the neuronal dendrites to be covered with dark spine-like thickenings. Electron microscopic analysis of the same preparations has revealed that the electron dense discrete formations represent synaptic terminals, situated on the dendrites with a definite periodicity. We discuss the use of such a method for the quantitative calculation of synapses in nerve tissue at the combined histological and electron microscopic levels of investigation.     

Changes in the ultrastructure and fibrogenic activity of rat dermal fibroblasts as affected by various doses of hydrocortisone

By means of electron microscopical morphometry and populational analysis it has been stated that hydrocortisone acetate, injected subcutaneously twice a week in dose 5 mg/kg of the body mass, produces decrease in number of intensively collagen-producing fibroblasts and increase in the part of fibroblasts and destroying cells in population of fibroblasts only in young (2-week-old) animals. The dose 10 mg/kg produces similar changes both in young and in mature (2-month-old) animals. In the young animals given hydrocortisone in dose 5 mg/kg of the body mass, the mean summational area and extension of the granular endoplasmic reticulum membranes in the fibroblast section diminishes, the summational area of the mitochondrial section decreases in the section of one cell, and the derm with less thickness, in comparison with the derm of intact animals, is formed, while in mature animals, given hydrocortisone in a small dose, all the parameters mentioned do not significantly differ from the control. Hydrocortisone in dose 20 mg/kg decreases all quantitative parameters of dermal fibroblasts both in young and mature animals. The data of the correlative analysis give evidence on the presence of a strong positive connection between inhibition of the synthetic apparatus of fibroblast development under hydrocortisone effect and decrease of the derm thickness, forming during the postnatal period of ontogenesis.     

Changes in the ultrastructure of neuromuscular synapses in rats under the effects of space flight factors

The influence of a 7-day space flight on board the biosputnik "Kosmos-1669" on the neuro-muscular synapses (NMS) of soleus, gastrocnemius and diaphragm muscles distinct in their functions has been studied. The synapse restructuring on the basis of destructive- regenerative process has been discovered. It is manifested to a great extent in the soleus muscle, to a lesser extent in the gastrocnemius muscle and the least of all in the diaphragm muscle. The changes observed in synapses may be caused by the attenuation of their function in weightlessness.     

Regulation of tetanus toxin-inhibited transmitter secretion in the neuromuscular junction in a calcium-free medium

The effect of Ca2+ removal from the external medium on regulation of the release of the synaptic transmitter in the tetanus toxin (TT)-inhibited neuromuscular junctions was studied on a rat phrenicodiaphragmal preparation with the aid of the conventional microelectrode technique of recording synaptic activity. As the external concentration of calcium was decreased from 2 to 0 mM, the frequency of miniature end plate potentials remained unchanged in the preparations isolated 3 to 3.5 h after intramuscular injection of TT (10(5) MLD for mouse). TT considerably reduced activation of the transmitter release, caused in intact synapses by ouabain (0.1 mM) and repetitive stimulation of the diaphragmatic nerve (50 imp/s). The data obtained indicate that in the TT-inhibited motor nerve terminals, the level of the transmitter release does not depend on the external concentration of calcium and that TT damages some of the intracellular sources of calcium.     

Colony formation by sublethally heat-injured Zygosaccharomyces rouxii as affected by solutes in the recovery medium and procedure for sterilizing medium

Recovery and colony formation by healthy and sublethally heat-injured cells of Zygosaccharomyces rouxii as influenced by the procedure for sterilizing recovery media (YM agar [YMA], wort agar, cornmeal agar, and oatmeal agar) were investigated. Media were supplemented with various concentrations of glucose, sucrose, glycerol, or sorbitol and sterilized by autoclaving (110 degrees C, 15 min) and by repeated treatment with steam (100 degrees C). An increase in sensitivity was observed when heat-injured cells were plated on glucose-supplemented YMA at an aw of 0.880 compared with aws of 0.933 and 0.998. Colonies which developed from unheated and heated cells on YMA at aws of 0.998 and 0.933 generally exceeded 0.5 mm in diameter within 3.5 to 4 days of incubation at 25 degrees C, whereas colonies formed on YMA at an aw of 0.880 typically did not exceed 0.5 mm in diameter until after 5.5 to 6.5 days of incubation. The number of colonies exceeding 0.5 mm in diameter which were formed by heat-injured cells on YMA at an aw of 0.880 was 2 to 3 logs less than the total number of colonies detected, i.e., on YMA at an aw of 0.933 and using no limits of exclusion based on colony diameter. A substantial portion of cells which survived heat treatment were sublethally injured as evidenced by increased sensitivity to a suboptimum aw (0.880). In no instance was recovery of Z. rouxii significantly affected by medium sterilization procedure when glucose or sorbitol was used as the aw-suppressing solute.(ABSTRACT TRUNCATED AT 250 WORDS)     

Changes in cholino- and adrenoceptors as affected by blood proteolytic enzymes

The effects of kallikrein, thrombin, and plasmin on interaction of acetylcholine and noradrenaline with receptors of the isolated portal vein of guinea-pigs were studied. The functional activity of receptors was studied by the pharmacokinetic method. It was found that kallikrein and thrombin do not disturb the kinetics of agonist interaction with receptors, whereas the magnitude of isometric vascular contractions dramatically decreased after plasmin treatment and becomes disproportionate to the concentration of neurotransmitters. Exposure of the portal vein to kallikrein or thrombin caused different changes in the sensitivity and quantity of active cholino- and adrenoreceptors. These proteolytic enzymes reduced the sensitivity of receptors to noradrenaline and increased it to acetylcholine. Exposure to kallikrein brought about a decrease in the quantity of active cholinoreceptors and a rise in the number of adrenoreceptors. The treatment of the vessels with thrombin resulted in a decrease in the number of active adrenoreceptors. The number of active cholinoreceptors remained unchanged.     

Changes in the ultrastructure of the chloride cells of sturgeon during adaptation to a hypertonic medium]

Alterations in the ultrastructure of chloride cells of young sturgeons Acipenser guldenstadti Brandt in the process of adaptation to hypertonic medium (S=105%) were under study. In the process of this adaptation thread-shaped long mitochondria became shorter, their random position was substituted by orientation in parallel to the axis of the cell. The amount of mitochrondria increased. A great number of vacuoles appeared in the cytoplasm. The character of the endoplasmic reticulum changed. The obtained data on the ultrastructure of chloride cells of the sturgeon confirm and supplement earlier light microscopy investigations of chloride cells of the sturgeon. The changes of the ultrastructure of chloride cells are interpreted as functional and adaptational ones.     

Plant cation-anion balance as affected by the ionic composition of the growing medium

Plants that remove an excess of cations over anions may cause soil acidification. The acidification potential of plants has been evaluated using solution culture techniques, but the influence of ionic composition of the medium on the plant cation-anion balance remains unclear. Our objective was to determine how electrolyte concentration and salt type affect the cation- anion balance of two test plants [barley (Hordeum vulgare L.) and kochia (Kochia scoparia L. Schrad.)]. Seedlings were grown in sand culture and irrigated with nutrient solution (Hoagland’s solution), which was adjusted to a range of electrolyte concentrations (target electrical conductivity of 7.5, 17.5 and 27.5 dS m⁻¹) using either chloride or sulphate salts. Increase in electrolyte concentration reduced yield of kochia, a salt-tolerant plant, by up to 38%. Total cation (Ca + Mg + K + Na) equivalents in kochia exceeded those of anions (Cl + S + P + NO₃) by 250 to 280 cmol_c kg⁻¹ of dry matter. Electrolyte concentration had no effect on the cation-anion balance of kochia, but excess cation values were significantly greater in the sulphate than in the chloride system. Kochia had a large content of water-soluble oxalate (194 to 226 cmol_c kg⁻¹), which was linearly related to the excess cation content. Growth of barley was severely restricted at the intermediate and high electrolyte concentrations. Cations exceeded anions by 21 to 59 cmol_c kg⁻¹ of barley dry matter. Excess cation content was greater in the sulphate than in the chloride medium, but electrolyte concentration did not have a consistent effect on the cation-anion balance. The small amounts of oxalate found in barley (0.9 to 2.6 cmol_c kg⁻¹) were insufficient to balance the cation excess.     

Changes in the ultrastructure of synapses and neurons of the ventral horns of the spinal cord in cats with tetany as a result of the removal of the parathyroid glands

An electron microscopic investigation on ultrastructure of synapses and ventral horns of the lumbar thickening in the spinal cord of cats with parathyroprival tetany has been performed. When motor disorders are clearly seen on the 2d - 4th days after removal of the parathyroid glands, together with the changes demonstrating functional activity of the synapses, certain irreversible degenerative changes of the "dark" type are seen in the axodendritic and axosomatic synapses. A complex of structural-metabolic changes has been revealed in the motor neurons, they have both functional-compensatory and degenerative character. It is possible to suggest that the changes revealed at parathyroprival tetany result from a disturbed metabolism and increased afferent influences.     

Heat resistance of Listeria monocytogenes in dairy products as affected by the growth medium

Listeria monocytogenes strains 1151 and Scott A were grown in broth at 30 °C and transferred to half cream, double cream and butter stored at 5 °C to determine the influence of dairy product composition on heat resistance at 52, 56, 60, 64 and 68 °C. Strain 1151 showed a higher heat resistance than strain Scott A. The heat resistance of both strains was higher in the dairy products than in broth, particularly at lower temperatures. A significant difference was observed between log 10 of the D -values in the different dairy products. The D -values obtained for both strains resuspended in all the dairy products would result in efficient elimination of the pathogen at 72·7 °C for 15 s. The highest D -value was 11·30 s at 68 °C and by using a z -value of 6·71 °C it can be determined that at 72·7 °C the D -value would be 1·5 s. The 15 s process would therefore achieve 10 log reductions. The effect of growth conditions on the heat resistance at 60 °C of L. monocytogenes Scott A was also investigated. When the cells were grown in the dairy products themselves, and particularly butter, the heat resistance of Scott A was enhanced; for example, the D -values were 7·15 times higher than in broth. Further studies are required to investigate if this protection against heating exists at higher temperatures, in which case the efficiency of pasteurization treatments or other heat treatments would be considerably lowered.     

Colony formation by sublethally heat-injured Zygosaccharomyces rouxii as affected by solutes in the recovery medium and procedure for sterilizing medium.

Recovery and colony formation by healthy and sublethally heat-injured cells of Zygosaccharomyces rouxii as influenced by the procedure for sterilizing recovery media (YM agar [YMA], wort agar, cornmeal agar, and oatmeal agar) were investigated. Media were supplemented with various concentrations of glucose, sucrose, glycerol, or sorbitol and sterilized by autoclaving (110 degrees C, 15 min) and by repeated treatment with steam (100 degrees C). An increase in sensitivity was observed when heat-injured cells were plated on glucose-supplemented YMA at an aw of 0.880 compared with aws of 0.933 and 0.998. Colonies which developed from unheated and heated cells on YMA at aws of 0.998 and 0.933 generally exceeded 0.5 mm in diameter within 3.5 to 4 days of incubation at 25 degrees C, whereas colonies formed on YMA at an aw of 0.880 typically did not exceed 0.5 mm in diameter until after 5.5 to 6.5 days of incubation. The number of colonies exceeding 0.5 mm in diameter which were formed by heat-injured cells on YMA at an aw of 0.880 was 2 to 3 logs less than the total number of colonies detected, i.e., on YMA at an aw of 0.933 and using no limits of exclusion based on colony diameter. A substantial portion of cells which survived heat treatment were sublethally injured as evidenced by increased sensitivity to a suboptimum aw (0.880). In no instance was recovery of Z. rouxii significantly affected by medium sterilization procedure when glucose or sorbitol was used as the aw-suppressing solute.(ABSTRACT TRUNCATED AT 250 WORDS)     

Ultrastructure and morphometric parameters of glutamatergic synapses on nigrothalamic and unidentified neurons of the reticular zone of theSubstantia nigra in cats

Nigrothalamic neurons were identified into thesubstantia nigra by their retrograde labelling with horseradish peroxidase. Axon terminals that contain glutamate (the excitatory transmitter) were revealed immunocytochemically with an immunogold electron microscopic technique. Ultrastructural parameters (the large and small diameters of axon terminals, area of their profiles, coefficient of form of profiles, large and small diameters of synaptic vesicles) were analyzed in all 240 synapses under study. Synaptic contacts localized on both nigrothalamic and unidentified neurons belonged to three morphologically specific groups. Synapses of the groups I and III, according to classification by Rinvik and Grofova, were characterized by a symmetric type of synaptic contact and contained polymorphic synaptic vesicles. Contacts in group-II synapses were asymmetric, and respective terminals contained round vesicles. Among the studied synapses, 65.8% were classified as group-I contacts, 25.0% belonged to group II, and 9.2% belonged to group III. Glutamate-positive axon terminals formed predominantly group-II synapses; such connections constituted 70% of this group's synapses. Sixty percent of glutamate-positive synapses were localized on the distal dendrites and 23% on the proximal dendrites, while 17% of such synapses were distributed on the somata of nigral neurons. Such a pattern of distribution of glutamate-positive synapses was observed on both nigrothalamic and unidentified nigral neurons. About 7% of glutamate-positive synapses were formed by very large axon terminals containing round synaptic vesicles; yet, the contacts of these terminals were of a symmetric type. Twenty percent of group-I synapses, i.e., synapses considered inhibitory connections, were found to manifest a weak immune reaction to glutamate.Neirofiziologiya/Neurophysiology, Vol. 28, No. 6, pp. 285–295, November–December, 1996.     

Effects of papaverine and calcium-free medium on salivary gland morphogenesis

Papaverine reversibly inhibits morphogenesis of cultured mouse salivary glands. The drug does not alter the morphology of epithelial cell microfilament systems or other organelles. Incubation in calcium-free medium also reversibly inhibits morphogenesis, though effects upon tissue integrity are possible.     

Production of imidazole alkaloids in cell cultures of jaborandi as affected by the medium pH

The effect of pH (from 4.8 to 9.8) on the production of pilosine and pilocarpine and on their partition between cell and medium was studied in two lineages (P and PP) of Pilocarpus microphyllus cell suspension cultures. Highest mass accumulation was observed at high pHs and both lineages produced pilocarpine while only lineage PP produced pilosine. Both alkaloids were released in the medium but higher accumulation occurred in the cells. The highest production of pilocarpine was at pH 8.8–9.8 in both cell lineages. Other imidazole alkaloids were also identified in both lineages. At all pHs tested, the pH in the media cultures tended to stabilize around 6 after 10–15 days of cultivation. NO₃ ⁻ and NH₄ ⁺ variation in the media might partially explain the pH stabilization.     

Changes in the population structure of the red-tailed Libyan jird as affected by toxicants

The kind of the regulating agent for the quantitative control of the epidemically dangerous species depends on the concrete tasks. The poison of the critical action causes a strong, but short-time effect. The pesticide inhibiting the reproductive system of the rodents exerts long and profound influence on the population structure.     

Changes in the ultrastructure of muscle fibers of the diaphragm in response to physical loading (morphometric analysis)

Red and white fibers have been investigated in the diaphragm of white rats, normal and under effect of physical loadings, various in intensity and duration. Relative volume and amount of lipid inclusions and mitochondria and their profiles and amount of glycogen granules have been estimated per one unit of the fiber section area. In unadapted animals acute physical loadings result in exhaustion of the reserves in the areas with a high volumetric density of mitochondria. These changes are mostly pronounced in the red fibers. Under a prolonged effect of the physical loadings of the training regimen, muscle fibers of both types have similar ultrastructural changes, demonstrating certain increase in their oxidative potential.