Influence of UV-B exclusion and selenium treatment on photochemical efficiency of photosystem II, yield and respiratory potential in pumpkins (Cucurbita pepo L.).

The influence of ambient and filtered solar ultraviolet-B (UV)-B radiation and of selenium treatment was determined on photochemical efficiency, respiratory potential measured by electron transport system (ETS) activity, and yield in pumpkins, Cucurbita pepo L. Yield and ETS activity were higher when solar UV-B was filtered out. The results suggested that the decreased yield was related to the UV-B impaired flow of electrons in the respiratory chain. Selenium increased yield under ambient radiation conditions. However, no significant effect of excluding UV-B radiation or of treatment with selenium was observed on the photochemical efficiency of photosystem II (PSII).     

Effect of beta-endorphin, enkephalins and their synthetic analogs on the neuronal electrical activity of the respiratory center in the medulla oblongata

It has been shown in experiments on conscious rabbits that beta-endorphine, enkephalins and their synthetic analogs as well as morphine suppress respiration depending on the dose. Naloxone completely reverses this effect of the drugs. While studying the mechanism of the suppressing action of morphine-like substances on respiration in experiments on anesthesized rabbits and cats, opioid peptides and morphine were applied microiontophoretically to the neurons of the bulbar respiratory center. These cells were found to be highly sensitive to the drugs (about 60% of both respiratory and reticular neurons were suppressed by microiontophoretic application of the drugs). Naloxone prevented the effects of opioids and morphine. It is assumed that the suppressing effect of endogenous opioid peptides and their synthetic analogs on respiration is determined to a considerable degree by direct influence of morphine-like substances on the neurons of the bulbar respiratory center.     

Electromagnetic radiation of the terahertz range at the nitric oxide frequency in correction and prophylaxis of functional activity disorders in thrombocytes of white rats under long-term stress

The influence of electromagnetic waves of terahertz range at the frequencies of molecular spectrum o nitric oxide radiation and absorption on functional activity of thrombocytes in white rats under long-term stress has been studied. It has been shown that courses of THzF treatment applied during the stress can prevent and restore disorders in thrombocytes aggregative function. The stress factor does not induce characteristic of stress-reaction disturbances of microcirculation in animals treated with the preventive course of THzF.     

Effect of mediodorsal thalamic nucleus on the respiratory neurons from medulla oblongata and the rat respiration during hypoxia]

In the normal as well as in the oxygen deficiency conditions the research has been conducted to study the influence of associative mediodorsal (MD) nucleus of thalamus on impulsive activity of respiratory neurons of medulla oblongata of respiration. In conditions of normal atmospheric pressure, before the uplift of the animals, the electrical stimulation of MD of nucleus of thalamus has had mainly inhibiting influence. In the initial phase, on 4-5 thousand meter altitude, activation of frequent discharge of neurons occurred, the respiration has become frequent as well. In this situation the inhibiting influence of stimulation of MD nucleus of thalamus was more accentuated than in conditions of normoxia. In the second phase, 7.5-8 thousand meters, the opposite occurred, i.e. reduction of respiratory center activity of medulla oblongata and thalamus. In this difficult conditions of hypoxia, a reduction of impulsive activity of neurons has been observed; the respiration was becoming slower and surface. Meanwhile, the inhibiting influence of thalamus was not significant.     

Influence of phospholipids on the respiratory activity of embryonal heart cells cultured in vitro in presence of different ethanol concentrations

The influence of phospholipids on respiratory activity of embryonal heart cells, trated with certainly harmful concentrations of ethanol, has been discussed. It has been concluded that when the cell is deeply impaired the administration of phospholipids does not seem to have positive effects. In this condition an irreversible morphological alteration has been induced.     

Structural and functional organization of the respiratory center

The main experimental data on the organization of the respiratory center accumulated during the past 200 years are summarized. It is emphasized that the existence of separate, reciprocally interrelated, inspiratory and expiratory centers has never been proved. The notion of multiple respiratory centers in the CNS, including pneumotaxic, apneustic, gasping, and deep-exhalation centers, which allegedly underlie the multiple forms of respiratory movements, is demonstrated to be unjustified. Upon systemic consideration, the evidence in favor of the decisive role of neurons of the pre-Bötzinger complex and preinspiratory neurons in initiating the respiratory rhythm and maintaining rhythm generation in the respiratory center is contradictory and unconvincing. It is assumed that the respiratory center located in the medullary region of the brain of intact animals and humans fulfills the main functions of endogenous self-sustained generation of the respiratory rhythm, chemoregulation, and mechanoregulation in the respiratory system in an integrated manner, according to the general requirements of the body at a given moment.     

Thyroliberin and its analog lacking hormonal properties stimulate respiratory center activity in the frog Rana temporaria

It has been shown that thyroliberin and its synthetic analogue PR-546 injected into the lymphatic sacs (4.10(-7)-4.10(-9) g/kg) or applied to the medulla oblongata in the bulbar frogs (4.10(-10)-4.10(-12) g/kg) significantly increase the rate of motor respiratory volleys in the hypoglossal nerve. In preparations with the irregular level of the activity of the respiratory center, these drugs enhanced stabilization of the initial level of the rhythm of motor respiratory discharges.     

Effect of metabolic inhibitors on formed novocaine and neutral red segregation zones in frog erythrocytes

Effects of some metabolic inhibitors, as well as of biologically active compounds (diakarb, ethidium bromide and a phenanthridine alkaloid sanguinarine) on the formed novocaine and neutral red segregation zones were studied. The volume of granules diminished under the influence of a glycolytic inhibitor iodoacetate, uncouplers of oxidative phosphorylation (2,4-dinitrophenol and carbonyl cyanide trifluoromethoxyphenylhydrozone), and respiratory inhibitors (antimycin A and rotenone), as well as under the influence of cycloheximide - an inhibitor of protein synthesis. Diakarb, ethidium bromide or sanguinarine also provoked a regression of the segregation zones. It has been found that all these compounds are inhibitors of ATPase activity of the isolated segregation zones. A possible mechanism of volume decreasing in segregation zones under the influence of both the metabolic inhibitors and diakarb, ethidium bromide and sanguinarine is discussed.     

Features of oxidative phosphorylation in brain mitochondria of rats with different sensitivity to oxygen insufficiency]

Oxidative phosphorylation parameters have been investigated in the isolated brain mitochondria of rats preliminary divided into non-resistant (NR) and high-resistant (HR) animals by their sensitivity to hypobaric hypoxia. During the NAD-dependent substrates oxidation it was shown that the identical effectiveness of the respiratory chain function in both groups of animals was reached at more tension of the oxidative processes. It has been established that at the identical effectiveness of the succinate oxidation by the brain mitochondria in both groups of animals compensatory potentialities of the succinate-oxidase pathway of oxidation is higher in the brain of the NR to hypoxia animals. It has been shown the regulated influence of the NAD-dependent pathway of oxidation activity on the succinate-oxidase site of respiratory chain. This influence is more expressed in the brain mitochondria of the NR animals that in the HR animals.     

Breathing pattern and metabolic behavior during anticipation of exercise

The mechanisms responsible for the marked increase in ventilation at the onset of exercise are incompletely defined. A conditioned response to exercise anticipation has been suggested as an influencing factor, but systematic measurements have not been made during the transition from rest to the time when exercise is anticipated but has not yet commenced. We tested the hypothesis that cortical activity associated with the anticipation of exercise causes hyperpnea, which is at least partly responsible for the increased ventilation at the onset of exercise. To assess the influence of continuous cortical activity in the absence of exercise anticipation the subjects performed mental arithmetic tasks. Fifteen subjects performed the two experiments in a random order. Ventilation was measured noninvasively using a calibrated respiratory inductive plethysmograph and end-tidal CO2 concentration (FETCO2) was monitored at the nasal vestibule. Both exercise anticipation and mental arithmetic caused an increase in minute ventilation (VI) (P less than 0.01) and mean inspiratory flow (VT/TI, P less than 0.01), which reflects respiratory center drive, although the derivation differed in that the former was volume based, whereas the latter was due to alteration in timing. Despite the increase in VI, FETCO2 remained constant in both instances. In a complementary study the constant FETCO2 in the face of increased VI was shown to be due to increased CO2 output. The results show that the mere anticipation of exercise causes an increase in ventilation. The mechanism responsible for this hyperpnea cannot be due solely to respiratory center activation because of the constancy of FETCO2 and the associated alterations in cardiac and metabolic behavior.     

Effect of Low-Intensity Pulsed Electric Fields on the Respiratory Activity and Electrosurface Properties of Bacteria

A change in the respiratory activity (RA) of the resistant to cyanide bacteria Pseudomonas fluorescens under the pulsed electric field treatment has been found experimentally. The bacteria reaction to the field treatment (rectangular impulses with the duration of 1 ms, voltage of 20 V, and frequency of 100 Hz) varied from the RA suppression of active culture to restoration and even stimulation of RA in cells with the decreased respiratory function, caused by the cyanide introduction. The interconnection of energetic membrane processes with the electrosurface properties of biocolloids has been demonstrated: The electrokinetic potential had been varied simultaneously with the respiratory activity change. Theoretical analysis of the experimental data indicates the change of quantity of active respiratory centers in cells under the influence of the pulsed electric field. These changes have reversible character. Depending on the state of bacteria, the processes of inhibition or restoration of the respiratory centers by the pulsed electric field can be observed.     

Significance of the corpus callosum in the paired activity of the respiratory center

The asymmetrical reactions of respiratory neurons of the right and left halves of the respiratory center and varied changes in bioelectrical activity of external intercostal muscles on both sides of the chest were discovered in experiments on anesthetized cats in response to successive electrical stimulation of the symmetrical cortical areas of the right and left cerebral hemispheres before and after callosotomy. It was demonstrated that callosotomy increased on both sides of the respiratory center the quantity of neurons responsive to ipsilateral cortical stimulation and determined the character of the asymmetrical reactions of right and left respiratory neurons and intercostal muscles. On the basis of the data obtained it is concluded that the corpus callosum contributes to the functional integration of both halves of the respiratory center.     

5'-Nucleotidase and adenosine deaminase activity in the rat brain upon prolonged effect of low radiation doses

The effect of combined low radiation doses (0.2-50.8 cGy) on the 5'-nucleotidase and adenosine deaminase activities in the rat hypothalamus, hippocamp and cerebral cortex during 45, 120 and 365 days was examined. It has been shown that the changes in the 5'-nucleotidase activity of the hypothalamus and hippocamp have a phase character. The direction of the changes in enzyme activity of the hypothalamus and hippocamp adenosine forming was dependent on the zone stay period and had the exactly opposite character depending on the early and prolonged stay period in the zone. 5'-nucleotidase activity was changed under the influence of mean and lesser doses with an increase of the zone stay period. No changes in the 5'-nucleotidase activity of the cerebral cortex were noted. No changes in the hypothalamic adenosine deaminase activity of rats that stayed in a zone during 45 days were revealed; under the effect of mean dose during 120 days the activity decreased and also in case of a higher dosage during one year. The adenosine deaminase activity in animal hippocamp decreased in rats only under the influence of the lesser dose, for 45-day period. The decrease in adenosine deaminase activity of the cerebral cortex that was noted under the effect of all the three doses during 45 days, the higher and mean doses during 120 days disappeared in a year.     

Effect of UV-B (290–320 nm) irradiation on growth and metabolism of cucumber cotyledons

Cucumber ( Cucumis sativus L. cv. Natsusairaku 3) seedlings were grown in a growth cabinet under UV-B (290–320 nm) irradiation (equivalent to the UV-B radiation normally incident at Tokyo, 36°N latitude, during clear sky conditions in mid-april on a weighted daily fluence basis) and a UV-B-free control condition. UV-B irradiation inhibited the growth of the cotyledons, i.e. the increase in area, and increase in fresh and dry weights of the cotyledons. The greatest inhibition rate was observed in the increase in area, causing a significant increase in specific leaf weight (the ratio of weight to area). UV-B irradiation had no significant effect on DNA and RNA contents in the cotyledons, but decreased protein content slightly. In contrast, the irradiation reduced the amounts of organic acids and soluble sugars, indicating that primary carbon metabolism was very sensitive to UV-B radiation. UV-B irradiation lowered the photosynthetic activity in the cotyledons without any effect on chlorophyll content and respiratory activity. These results indicate that UV-B radiation at the ambient level may act as a physiological stress in some UV-sensitive plants.     

Antioxidative activity of flavonoids in stimulated human neutrophils

The release and production of oxidative products generated by the respiratory burst under the influence of natural flavonoids: quercetin, kaempferol and isorhamnetin derivatives have been studied in the polymorphonuclear neutrophils (PMNs) from healthy human donors. Flavonoids were tested in vitro at concentration range 1-100 microM. The antioxidative potential of flavonoids was compared to the activity of a food preservative, butylated hydroxyanisole. Two methods were applied to the measurement of the PMNs respiratory burst: flow cytometry using dichlorofluorescein diacetate and luminol-dependent chemiluminescence. It was found that the studied products decreased the neutrophil hydrogen peroxide production in concentration-dependent manner. The highest degree of inhibition was registered for concentration of 100 microM, although in the chemiluminescence method the metabolic activity inhibition was more prominent. Antioxidative activity of flavonoids depended on the number of hydroxyl groups. These results provide useful data for establishing methods used to assess the respiratory burst in phagocytic cells.     

Influence of the ventral surface of the medulla on tracheal responses to CO2

These studies investigated the role of the intermediate area of the ventral surface of the medulla (VMS) in the tracheal constriction produced by hypercapnia. Experiments were performed in chloralose-anesthetized, paralyzed, and artificially ventilated cats. Airway responses were assessed from pressure changes in a bypassed segment of the rostral cervical trachea. Hyperoxic hypercapnia increased tracheal pressure and phrenic nerve activity. Intravenous atropine pretreatment or vagotomy abolished the changes in tracheal pressure without affecting phrenic nerve discharge. Rapid cooling of the intermediate area reversed the tracheal constriction produced by hypercapnia. Graded cooling produced a progressive reduction in the changes in maximal tracheal pressure and phrenic nerve discharge responses caused by hypercapnia. Cooling the intermediate area to 20 degrees C significantly elevated the CO2 thresholds of both responses. These findings demonstrate that structures near the intermediate area of the VMS play a role in the neural cholinergic responses of the tracheal segment to CO2. It is possible that neurons or fibers in intermediate area influence the motor nuclei innervating the trachea. Alternatively, airway tone may be linked to respiratory motor activity so that medullary interventions that influence respiratory motor activity also alter bronchomotor tone.     

The effect of the biochemical adaptations in the Manchu alder (Duschecia fruticosa (Rupr)) to an elevated natural radiation background on the survivability of seedlings and on the radiosensitivity of its seeds

Seeds and sprouts of bushy alder existing for long under the condition of the enhances natural radiation background (ENRB; from 1.4 to 72.0 mCu/(kg.s)) have been examined to determine biochemical adaptations to permanent low-level irradiation. To achieve this goal a combined cytological and biochemical technique for the assessment of the activity of genome of the sprout root meristem in response to translation, replication and reparation has been applied. The activity of antioxidant systems has been studied. The data obtained allow us to reveal mechanisms of alder bush biochemical adaptations to various ENRB rates and their effect upon seeds radiosensitivity and sprouts survival. It is determined that the increase in sprout vitality and high radioresistance of seeds ripened under the conditions of low-level natural radiation is due to the content of low molecular antioxidants and activation of systems of genome reparation.     

The electrical activity of the dorsal wall of the rat trachea]

It was demonstrated that changes in the diameter of respiratory pathways during respiration process are associated with the activity of the plain muscles of the walls. Formation of this activity in a form of potential groups during inspiration phase is realized by the peripheral nervous apparatus. Co-ordination of the activity of this apparatus with the work of the respiratory center is realized via efferent vagal fibres.     

The effect of the causative agent of tick-borne relapsing fever on the respiration of the vector Ornithodoros papillipes (Birula, 1895) (Ixodoidea, Argasidae)

A relatively low level of normal respiratory metabolism in O. papillipes has been observed as compared to most other invertebrates and even ixodid ticks. It is connected with biological peculiarities and habitat of this species. Changes in respiratory metabolism under the influence of Borrelia have been revealed. These changes vary at different stages of tick life cycle. In long-fasting infected individuals, respiration is further inhibited, and in nourished ones, is increased as compared to noninfected ticks.