Respiration rate dynamics during early ontogenesis in amphibians

We studied growth and respiration rate during early ontogenesis of the axolotlAmbystoma mexicanum, Bosca’s newtTriturus waltlii, the green toadBufo viridis, and the smooth clawed frogXenopus laevis. The respiration rate in these amphibian species increases during embryonal and larval development, peaks after transition to active feeding, and decreases at later stages of ontogenesis. The patterns of dynamics of this energy metabolism, index in tailed and tailless amphibians have some differences related to their specific development. The changes in respiration rate in the embryos and larvae are correlated with the concentrations of mitochondria.     

Phosphorylation and uncoupled respiration in the tissue of rats during the development of homoiothermy

A marked increase in the rate of mitochondrial respiration, not coupled with ADP phosphorylation, was noted during the transformation of newborn poikilothermic animals into homoeothermic ones in the experiment on the rat tissue homogenates. Uncoupled respiration, as well as coupled one, is realized by the mitochondrial respiration chain, is observed upon oxidation of NADH, succinate, ascorbate and is expressed by a high rate of O2 consumption in the absence of added ADP. During ontogenesis, uncoupled respiration is activated to a greater extent in the heart and skeletal muscle and to a lesser extent in the liver and brown fat. The rates of phosphorylating oxidation of different substrates in tissue homogenates of animals from various age groups differ insignificantly. It is supposed that the postnatal development of homoeothermism in rats is ensured by the formation in many tissues of a system of uncoupled respiration, which takes part in heat production without preliminary ATP synthesis.     

Change in intensity of respiration in development of some invertebrates

We studied the dynamic of respiration intensity during ontogenesis of flat worms (Dugesia tigrina), molluscs (Anodonta piscinalis and Viviparus viviparus, and insects (Leptinotarsa decemlineata). In planarians that reproduce vegetatively, the intensity of respiration increases just after fission and decreases at the subsequent phases of growth. In A. piscinalis, this index of metabolism increases during embryonic and early larval development and decreases at the later developmental stages. In V. viviparus, which develops in the female genital tract, the intensity of respiration remains unchanged during embryogenesis and decreases during late embryogenesis and subsequent phases of growth. In L. decemlineata, the intensity of respiration increases during embryonic and early larval development and then decreases to undergo cyclic changes times to molts. This index markedly decreases in the pupae, increases in the beginning of imaginal period, and then again decreases.     

Changes in the Intensity of Respiration during Ontogenesis of Some Invertebrates

We studied the dynamic of respiration intensity during ontogenesis of flat worms (Dugesia tigrina), molluscs (Anodonta piscinalis and Viviparus viviparus, and insects (Leptinotarsa decemlineata). In planarians that reproduce vegetatively, the intensity of respiration increases just after fission and decreases at the subsequent phases of growth. In A. piscinalis, this index of metabolism increases during embryonic and early larval development and decreases at the later developmental stages. In V. viviparus, which develops in the female genital tract, the intensity of respiration remains unchanged during embryogenesis and decreases during late embryogenesis and subsequent phases of growth. In L. decemlineata, the intensity of respiration increases during embryonic and early larval development and then decreases to undergo cyclic changes times to molts. This index markedly decreases in the pupae, increases in the beginning of imaginal period, and then again decreases.     

Mitochondrial calcium flux in temperature-sensitive mutants of

The mechanisms of mitochondrial calcium flux in normal and temperature-sensitive mutants of were investigated. Adult mitochondria from all stocks, when analysed with an oxygen electrode, gave respiration rates which exhibited normal responses to adenosine diphosphate and uncoupling agents but no stimulation by calcium. In contrast, calcium stimulates the respiration rate of normal larval mitochondria particularly those of the second instar. This is not evident in second instar mitochondria from the temperature sensitive mutants. There is a rapid accumulation of mitochondrial calcium during normal larval ontogenesis. The levels in temperature-sensitive second instar mitochondria are higher than those of any of the normal larval stages. Adult mitochondria in all cases contain very low levels of calcium. The amount of calcium taken up by mitochondria of second instar temperature-sensitive mutants is lower than that of normal. This may reflect the higher endogenous levels already present in the former. The implications of these variations in calcium metabolism for the behavioural defects of the temperature sensitive mutants is discussed.     

Mitochondrial calcium flux in temperature-sensitive mutants of Drosophila

The mechanisms of mitochondrial calcium flux in normal and temperature-sensitive mutants of $\text{Drosophila}$ were investigated. Adult mitochondria from all stocks, when analysed with an oxygen electrode, gave respiration rates which exhibited normal responses to adenosine diphosphate and uncoupling agents but no stimulation by calcium. In contrast, calcium stimulates the respiration rate of normal larval mitochondria particularly those of the second instar. This is not evident in second instar mitochondria from the temperature sensitive mutants. There is a rapid accumulation of mitochondrial calcium during normal larval ontogenesis. The levels in temperature-sensitive second instar mitochondria are higher than those of any of the normal larval stages. Adult mitochondria in all cases contain very low levels of calcium. The amount of calcium taken up by mitochondria of second instar temperature-sensitive mutants is lower than that of normal. This may reflect the higher endogenous levels already present in the former. The implications of these variations in calcium metabolism for the behavioural defects of the temperature sensitive mutants is discussed.     

Experimental assessment of embryotoxic action of low intensity ionizing irradiation in different periods of intrauterine development

The prolonged ionizing radiation exposure at the absorbed doze rate of 2.6 mGy/hour and the total accumulated doze of about 20 cGy during different periods of the intrauterine development caused disorders of a coordinated development of organs and the decrease of endurance in physical activity in the postnatal ontogenesis of the irradiated posterity. The results obtained are comparable to the consequences of irradiation exposure of the fetus at the accumulated doze of 125 cGy during all stages of pregnancy and give grounds for considering radiation exposure at the above-mentioned rate (20 cGy) as a biologically significant factor.     

The dynamics of the index of stress in ontogeny

Mathematical analysis of the heart rate in foetuses reveals the progressive development of regulatory mechanisms which account for fetal maturity. The decrease in sympathetic tonic mechanisms, the onset and development of normo- and vagotonic mechanisms of regulation of chronotropic function of the heart were revealed in postnatal ontogenesis. Phasic structure of regulatory processes during the increase in loading was observed in the organism of children, infants and young subjects.     

Secondary rhythms of automatically functioning systems

In wakeful rats at the age from newborn to 3 weeks there were studied interrelations of rhythmical oscillations of heart rate, respiration rate, and periodic spontaneous motor activity. In all studied systems, these oscillations are coordinated and occur in several frequency diapasons. Frequencies in the near-minute diapason (the period from 30 to 90 s) are the most constant and do not change with age. Regular oscillations are the most stable in newborns. Bursts of motor activity usually are irregular, but episodically the distinct near-minute rhythm is traced. Studies of the character of interaction of the heart activity, respiration, and periodic somatomotor excitation allow stating that the main coordination pathway of spontaneous autorhythmic functions in early postnatal ontogenesis is formation of secondary rhythms. Possible ways of formation of the secondary rhythms are considered.     

Postnatal physiological development of rats after acute prenatal hypoxia

The aim of study was to investigate the physiological development of the brain and behaviour in rats subjected to prenatal hypoxia on the 13.5th day of embryogenesis. We have found that such rats manifested a delayed physiological development and a change in nervous tissue of the sensorimotor cortex, as well a disturbed formation of motor responses during the first month of postnatal ontogenesis. During maturation these modifications were in part compensated, however we observed a decrease of the rats' ability to learn new forepaw movements. The destruction of the brain tissue and the modification of neurons composition in the sensorimotor cortex correlated with changes of behaviour at different stages of ontogenesis. Thus, changes of the conditions under which an organism develops during embryogenesis, predetermine a disturbance in ontogenesis and the learning ability.     

Postnatal development of amino acid metabolism enzymes in the liver and muscle of 'cafeteria' rats

The effect of feeding a high-energy highly palatable cafeteria diet on the liver and muscle ontogenesis of serine dehydratase, alanine transaminase, glutamine synthetase and adenylate deaminase during postnatal development of the rat has been studied. The results are in agreement with the lower amino acid utilization in cafeteria rats, both adults and during postnatal development. The feeding of excess energy coupled with high-quality protein resulted in changes in the ontogenesis of the studied enzymes that coincide with the development of protein synthesis and overall pup growth even before they had direct access to this rich diet, suggesting that cafeteria feeding already affects the amino acid metabolism of the pup through the dam's milk.     

Energy Metabolism in Postlarval Ontogenesis of Planorbarius corneus (Planorbidae,Gastropoda)

Russian Journal of Developmental Biology - The change in the rate and mass-specific rate of oxygen consumption was studied during individual ontogenesis of nine Planorbarius corneus individuals...     

The role of serotonin in the immune system development and functioning during ontogenesis

In this study, we investigated the influence of serotonin on the development and functioning of T- and B-cell-mediated immunity during ontogenesis using the pharmacological model of serotonin depletion in rat fetuses. It has been demonstrated that prenatal serotonin deficiency resulted in a decrease in thymus and spleen weights, changes in their cellular composition, and long-lasting disturbances in cell-mediated and humoral immunity in postnatal ontogenesis. The data obtained suggest that serotonin may be considered a morphogenic factor in development of the immune system.     

Dynamics of glucocorticoids in the ontogenesis of freshwater crawfish Astacus leptodactylus Esch

Dynamics of changes in glucocorticoid (hydrocortisone and corticosterone) levels was studied in the ontogenesis of freshwater crawfish Astacus Leptodactylus Esch. It was shown that steroid concentrations increase during the embryogenesis period. Decrease in the glucocorticoid levels during postembryonic development is most probably related to the stabilization of young fish growth and the attainment of hormone levels typical for adult individuals. The correlation ofglucocorticoid levels with physiological-biochemical changes at different stages of ontogenesis indicates that these steroids play an essential role in the regulation of freshwater crawfish vital functions.     

Characteristics of Basic Parameters of the Hormonal Function of the Adrenal Cortex and Its Modification in Rat Ontogenesis

The stress-reactivity of the pituitary-adrenocortical system (PAS) as assessed by the dynamics of the blood corticosterone level changes was studied in rats administered with cortisol at different periods of their pre- and postnatal ontogenesis. The participation of the activation and deactivation mechanisms in this process was estimated by means of a mathematical modeling, using the basic parameters of hormonal wave. It is established that in the one-month old rat pups born from mothers injected with cortisol from the day 14 to 18 of pregnancy, the basal and stress-evoked PAS activity was not essentially changed, whereas the adult animals demonstrated a faster decrease of the stress-induced corticosterone level. Injection of cortisol at the early neonatal ontogenesis (1–5 day of life) decreased the basal and stress-induced corticosterone levels at the morning hours in one-month old rats, whereas in adult rats it increased the PAS stress-reactivity. Injection of cortisol in the late neonatal ontogenesis, i.e., during the period of formation of the sensory systems (opening of the ears, eyes, maximal motor activity) resulted predominantly in changing the time of completion of the stress-induced hormonal response that became longer than in control animals of the same age. With the aid of mathematical modeling, we have found that at the early neonatal period of development the hormonal exposure mainly increases the rate of PAS activation, whereas injection of glucocorticoids at the late neonatal period changes PAS regulation by a feedback mechanism, thus decreasing the rate of system inactivation and increasing the time of completion of PAS stress-induced reaction. It is concluded that the phenotypic reorganization of PAS stress-reactivity by exogenous corticosteroids depends on the time of their action on development of the excitatory and inhibitory mechanisms during the critical periods of their formation.     

百合花朵不同发育期乙烯释放量与膜脂过氧化作用的研究

以百合（lilium)“精萃”为材料,研究了百合花朵的不同发育期与乙烯释放量,呼吸强度变化情况,发现百合花朵的乙烯释放量和呼吸强度变化趋势基本一致,属于乙烯末期上升型花卉,并发现随着花朵的发育,不饱合脂肪酸指数（IuFA)逐渐下降,丙二醛（MDA）上升,细胞膜相对透性增加。     

Deviation of the living system from the stationary state during oogenesis

Summary The changes in respiration and glycolysis of whole oocytes and homogenates of oocytes during oogenesis have been studied.The respiration rate of whole oocytes increases during oocyte growth and decreases during oocyte maturation. The respiration rate of homogenates also increases during oocyte growth and does not change during egg maturation. At all oogenesis stages the respiration rate of homogenates is higher than the respiration rate of whole oocytes.Respiration intensity increases during the small growth stage and decreases during the following stages of oogenesis. Respiration intensity of homogenates under optimal conditions changes in a similar way. Respiration intensity under physiological conditions diminishes during oogenesis from 70% at the small growth stage to 42% in unfertilised eggs.The rate of glycolysis in whole oocytes and homogenates of oocytes increases during the growth period of oocytes but does not change during egg maturation.Glycolysis intensity of the whole oocytes increases at the large growth stage—stage of cytoplasmic vacuolisation—and becomes less during the following stages. Glycolysis intensity in homogenates under optimal conditions is much higher than the glycolysis intensity of whole oocytes and it decreases slightly during oogenesis. The efficiency of glycolysis in oocytes under physiological conditions is very low. It increases from the stage of cytoplasmic vacuolisation (3.6%) to the stage at which vitellogenesis starts (20%) and diminishes at the following stages.The data obtained are considered in the light of the Prigogine and Wiame interpretation of a thermodynamic theory of development.     

Changes in lactate dehydrogenase activity in chicken tissues in hyperthyreosis in ontogenesis

The lactate dehydrogenase activity in reactions of lactate oxidation and synthesis was studied in subfractions of the chicken brain, heart and liver at the embryonal, early postembryonal and adult stages of development after thyroxine administration. It has been shown that during embryogenesis thyroxine predominantly enhanced the rate of lactate oxidation in the mitochondrial tissues. A marked increase in the lactate synthesis was found in cytoplasm of the adult chicken tissues. Specificity of enzyme activity alterations was detected in the chicken brain during ontogenesis after thyroxine administration.     

Development of different types of muscle fiber in the postnatal ontogeny of guinea pigs

As demonstrates estimation of myosin ATPase and SDG activity, the guinea pig is already born with differentiated muscle fibers (MF), and the first histochemical differences between them take place in the uterine 10 days before birth. Tonic oxidative fibers of the first type, arranging hexagonally, develop especially quickly at early stages of postnatal ontogenesis. Their relative contents up to the end of the observations (185 days) do not change, and area of their transversal section increases but slightly in comparison to the phasic fibers. The main age changes of the muscle tissue are connected with formation and rearrangement of the phasic fibers. The most intensive reconstructions of the phasic fibers coincide with the period of game activity and sex maturation. In mixed muscles the part of the glycolytic fibers increase during the postnatal ontogenesis. In the process of ontogenesis the soleus muscle fully consists of oxidative fibers. The definitive level of the MF development is established after the guinea pigs have reached their sex maturation. Comparing the results of the given investigation with the previous data on development of MF in rats, it is possible to conclude that term and premature animals have various rates in development of the muscle system, however, main stages of myogenesis coincide, though they are connected with various phases of ontogenesis.     

Development of glands of internal secretion in birds and immaturely-born mammals

Certain general problems on foundation of the hormonal regulation mechanisms during the prenatal and early postnatal ontogenesis are discussed basing on the authors' own results and on the literature data. They concern development of the hypophysis and peripheral target-glands in immaturely-bone Mammalia and fowls. The data on foundation of the endocrine glands functional activity are compared in rats and hens. The notion on a relative autonomous hormonal function of the peripheral endocrine glands at early stages of ontogenesis is motivated.