Morphofunctional properties of red blood cells in humans during seven-day “Dry” immersion

Healthy male volunteers were subjected to seven-day “dry” immersion. After that, morphological and biochemical features of erythrocytes, erythropoiesis intensity, including the indices of iron metabolism and erythropoietin, lipid and phospholipid spectrum of the plasma membrane of erythrocytes, and the efficiency of binding and release of oxygen by hemoglobin were studied. The studies were performed before immersion, at the last seventh day of immersion, and on the 7th and 15th days of the recovery period. We found that seven-day “dry” immersion tended to change morphological composition of red blood, erythropoiesis intensity, and metabolic indices in erythrocytes. Seven-day simulated microgravity resulted in significant changes in the indices of oxygen-transporting function of erythrocytes, probably, due to changes at the membrane level and, particularly, in phospholipid fractions. These changes have no clinical importance, because all of them returned to the baseline after the 15-day recovery period. Substantial variability of data is related to an individual response of the body to stress induced by experimental conditions.     

Research on the peripheral hemodynamics by the method of ultrasonic doppler examination under the conditions of seven-day immersion

Peripheral blood circulation was investigated in the experiment with “dry” immersion by the method of ultrasonic Doppler examination, including transcranial Doppler examination. The linear blood velocity (LBV) in the main arteries and veins of the head and lower extremities was recorded in eight healthy volunteers who stayed in an immersion bath for seven days. The examinations were carried out on day 2 and 5 of immersion and on day 2 of the rehabilitation period. The results were compared with the background values of the blood velocities. The LBV was revealed to slow down in all the examined main arteries and veins of the head and lower extremities; the changes were the most pronounced in the venous system. The dynamics of the venous cerebral blood flow that indirectly attests to the elevation of intracranial pressure was observed on day 5 in some of the volunteers. In the period of recovery, the parameters of the arterial LBV mainly returned to the background values, while the venous blood circulation recovered slower, which indicated an aftereffect of support deprivation factors.     

Specific Features of Metabolism in Humans Performing a Physical Exercise Test after 7-Day Dry Immersion

Healthy male volunteers (n = 5) aged 27–42 years participated in experimental studies (7-day immersion) designed to simulate the effects of microgravity. To study the metabolic changes caused by decreased weight bearing on the musculoskeletal system and a change in the position of the body relative to the gravity vector, a 15-min load test before and after immersion was used. A wide set of biochemical parameters characterizing the state of the energy metabolism, substrate levees, and enzyme activities, as well as the blood level of hormones, was measured in the blood plasma. Multifactor analysis was used in processing the experimental data. After immersion, a significant decrease in the blood plasma activity of isocitrate dehydrogenase, creatine phosphokinase, and lactate dehydrogenase was noted, whereas the growth hormone and insulin levels exceeded the baseline values. The physical exercise test increased the differences in the metabolic status before and after 7 days of immersion. The factor analysis allowed us to reveal the most significant biochemical variables for identifying a new metabolic state of the physiological systems after exposure to short-term simulated microgravity. Changes in the creatine phosphokinase activity and the human blood plasma levels of cortisol, triglycerides, insulin, and inorganic phosphate made the most significant contributions to these differences, and the direction of biochemical shifts in response to exercise was different before and after immersion. The results obtained are indicate that energy and substrate metabolism changes in response to a decrease in weight bearing and an altered body position relative to the gravity vector and that these changes are especially pronounced when an exercise test is used.     

Metabolic responses of the body to breathing with hypoxic argon–oxygen and nitrogen–oxygen mixtures

We have studied metabolic responses of six male volunteers who were exposed to hypoxic nitrogen–oxygen and argon–oxygen respiratory mixtures under hermetic chamber conditions for a long time. We measured the values of 44 biochemical parameters of venous blood, which reflected the state of different parts of metabolism, as well as the state of organs and tissues. Under the conditions of argon–oxygen respiratory mixture with the level of oxygen of 12.8% within the first five days and 12.0% from six to ten days of the experiment, the activation of processes of anaerobic glycolysis and lipolysis with the development of metabolic acidosis was observed. Against this background, biochemical signs of unfavorable changes in the myocardium were recorded. When we used the nitrogen–oxygen respiratory mixture with the level of oxygen of 13.0% during the first five days of the experiment and 12.1% from the sixth to the tenth day, these changes were expressed much more significantly: the activation of lipolysis and a decrease in the level of serum iron were observed and the signs of damage of mitochondria, depression of the kidney function, and development of hypodynamia were recorded. Complete stabilization of metabolic processes was reached only after seven to eight days of the recovery period for both mixtures. These findings lead to the conclusion that it is physiologically more preferable to use oxygen–argon respiratory mixtures at small immersion depths.     

Biological responses to overload training in endurance sports

Five subjects undertook 10 days of twice daily interval training sessions on a treadmill followed by 5 days of active recovery. On days 1, 6, 11, and 16 the subjects were required to undertake a test of submaximal and maximal work capacity on a treadmill combined with a performance test consisting of a run to exhaustion with the treadmill set at 18 km.h-1 and 1% gradient. Also on these days a pre-exercise blood sample was collected and analysed for a range of haematological, biochemical and immunological parameters. The subjects experienced a significant fall in performance on day 11 which had returned to pretraining levels on day 16. Serum ferritin concentrations were depressed significantly from pretraining concentrations at the conclusion of the recovery period while the expression of lymphocyte activation antigens (CD25+ and HLA-DR+) was increased both after the training phase and the recovery phase. The number of CD56+ cells in the peripheral circulation was depressed at the conclusion of the recovery period. Several parameters previously reported to change in association with overload training failing to reflect the decrease in performance experienced by subjects in this study, suggesting that overtraining may best be diagnosed through a multifactorial approach to the recognition of symptoms. The most important factor to consider may be a decrease in the level of performance following a regeneration period. The magnitude of this decreased performance necessary for the diagnosis of overtraining and the nature of an "appropriate" regeneration period are, however, difficult to define and may vary depending upon the training background of the subjects and the nature of the preceding training. It may or may not be associated with biochemical, haematological, physiological and immunological indicators. Individual cases may present a different range of symptoms and diagnosis of overtraining should not be excluded based on the failure of blood parameters to demonstrate variation. However, blood parameters may be useful to identify possible aetiology in each separate case report of over-training. An outstanding factor to emerge from this study was the difficulty associated with an objective diagnosis of overtraining and this is a possible reason why there have been new accounts of overtraining research in the literature.     

Sublethal effects of an organophosphorus insecticide (RPR-II) on biochemical parameters of tilapia, Oreochromis mossambicus

The effect of exposure to sublethal concentrations (0.017 mg L(-1), 1/10 of LC50) of the novel organophosphate (OP) insecticide, 2-butenoic acid-3-(diethoxyphosphinothioyl) methyl ester (RPR-II) on biochemical parameters in Oreochromis mossambicus was studied during exposure for 3, 7, 15, 30 and its recovery response after seven days. Acetylcholinesterase (AChE) activity of brain, gill and muscle was inhibited by 67%, 77% and 73% respectively on day-30. The plasma and kidney alanine aminotransferase (AlaAT), and aspartate aminotransferase (AspAT) activity increased, while decreases were observed in gill and liver. Increases in acid phosphatase (AcP), and alkaline phosphatase (AP) activities were observed in plasma, gill, and kidney, and reductions of 20% and 61% in liver AcP and AP, respectively. Depletion of glycogen was observed in all tissues, an indication of typical stress related response of the fish with pesticide. Lactate dehydrogenase (LDH) activity decreased in liver and muscle, indicating tissue damage but a significant increase in LDH activity in gill and brain was observed. Depletion of glutathione (GSH) was observed in all tissues, thereby enhancing lipid peroxidation resulting in cell damage. The induction in hepatic glutathione-S-transferase (GST) levels indicates protection against the toxicity of xenobiotic-induced lipid peroxidation. There was a significant recovery in the above biochemical parameters, in all tissues of fish after a recovery period of seven days. These results revealed that the OP insecticide RPR-II is highly toxic and affects the intermediary metabolism of O. mossambicus.     

Acoustic and spirometry parameters of forced expiratory sounds during a five-day dry immersion

The dynamic studies of the parameters of forced expiration under the conditions of a five-day dry immersion involved seven healthy male subjects aged 20 to 25 years. During forced expiration, spirometry tests were performed simultaneously with tracheal sounds being recorded by a microphone. A number of parameters, including the acoustic duration of the forced-expiration tracheal sounds, the lungs’ forced vital capacity, the 1-s forced expiration volume, the peak expiratory flow, and time of achieving the peak expiratory flow, were recorded before dry immersion, on days 1 and 4 of immersion, and the next day after the termination of immersion. There was a significant decrease (by 8.4%) in the peak expiratory flow on day 1 of immersion; however, by day 4 of immersion, the peak expiratory flow increased by 8.9%, reaching its baseline values. The lungs’ forced vital capacity and the forced expiration volume during 1 second, on the average, did not change throughout the experiment. There was a significant increase (by 17%) in the duration of the forced expiration tracheal sounds after the immersion, which suggests an increase in respiratory resistance and needs further studies. A moderate negative correlation between the duration of the forced expiration tracheal sounds and Gensler’s index (r = ?0.63) was found, whereas the correlation with other spirometry parameters was weak or absent.     

Effect of optokinetic stimulation on visual–manual tracking under the conditions of support-proprioceptive deprivation

The effects of additional dynamic visual stimuli (retinal optokinetic stimulation (ROKS)) on the visual–manual tracking (VMT) indicators in the absence of support afferentation and with a reduced level of proprioceptive afferentation were determined using a model of horizontal “dry” immersion. The accuracy of the VMT of jerky and smooth (linear, pendular, and circular) movements represented by visual dot stimuli was evaluated in all 18 participants aged 19–31 before, during and after their exposure to a five- to seven-day immersion bath. The eye movements were recorded by electrooculography, while the hand movements were recorded by a joystick with a biological visual feedback (the current angle of the joystick handle was imaged on the screen). Computerized visual stimulation tests were presented, through virtual reality glasses, to subjects in the absence and against the background ROKS. We analyzed the temporal and the amplitude- and velocity-related visual and manual tracking (VT and MT) characteristics, including the efficiency (e) and gain (g) coefficients as the ratios between the amplitudes and velocities of eye/hand movements and the amplitude of stimulus movements. The efficiency and gain coefficients of both VT and MT without ROKS were significantly decreased against the baseline during the entire period including three days of immersion and 3 post-immersion days. The most pronounced worsening was observed in the VT parameters. Whereas the VT and MT parameters remained unchanged against the threshold ROKS before the immersion, they were improved during and after the immersion (the improvement was significant on the fifth to seventh day of immersion and on the thirdthird post-immersion day, compared to the test indicators on the clean screen). The most pronounced impact of ROKS was observed in the VT parameters. The vestibular function (VF) was evaluated by videooculography before and after immersion. We analyzed the static torsional otolith-cervicalocular reflex (OCOR), dynamic vestibular-cervical-ocular reactions (VCOR), vestibular reactivity (VR), and spontaneous eye movements (SpEM). A significant decrease in OCOR (gOCOR was 0.1, compared to the background gOCOR value of 0.25) was detected alongside a simultaneous significant increase in the VCOR/VR parameters in 28% of subjects on day R + 1 after immersion. Correlational has been found between the parameters of VT and MT, as well as between those of VF and VT, but no correlation has been found between the VF and MT characteristics. The results have shown that the removal of support afferentation and the minimization of proprioceptive afferentation more affected the accuracy of VT rather than that of MT. The correlational links between the studied parameters against the background of ROKS were not only preserved, but also intensified. The obtained results confirm the development of sensory deprivation (and afferent deficit) under the exposure to an immersion bath and indicate the approach to correcting the sensory deprivation through additional ROKS.     

The effect of sub-lethal exposure to copper and the time course of recovery in clean water on biochemical changes in juvenile fish (Acipenser persicus)

This study reports the 96-h LC₅₀ value and tissue copper (Cu) levels and biochemical changes in juvenile fish (Acipenser persicus) exposed to 0.026?mg/l ambient Cu for 1, 7 and 14?days. It then examined the recovery of the same parameters after placing the juvenile fish in clean water for a further period of 28?days. The intestine, kidney and gill Cu levels, plasma glucose, total protein, triglyceride, cortisol, triiodothyronine and thyroxine concentrations, liver protein contents, liver catalase, superoxide dismutase (SOD) and glutathione S-transferase activities were studied. The 96-h LC₅₀ value of Cu was 0.502?mg/l for juvenile A. persicus. The results indicate that Cu exposure produced significant accumulations of Cu in gills and kidney over the treatment time. Sublethal dose of Cu resulted in a short-term increase in plasma glucose, total protein and cortisol levels that decreased with time. After the 28-day recovery phase, there were significant differences in kidney Cu levels and triglyceride concentrations as well as SOD activities between recovery fish treatments and their control groups on day 42. The 28-day recovery phase caused significant decreases in total protein levels and SOD activities of Cu-exposed fish on day 42 compared to day 14. The results suggest that 28?days are insufficient for complete recovery to Cu exposure by juveniles and a longer period would be required for full recovery. Moreover, the study showed that the recovery phase following Cu exposure could change biochemical parameters to levels that are not close to those seen during exposure or control levels.     

Visual-manual tracking during a five-day dry immersion

The effect of low proprioceptive, tactile, and support afferentation on visual-manual tracking was determined using a five-day horizontal dry immersion, which provided support deprivation, as well as minimization of muscle activity and proprioceptive afferentation, simulating the physiological effects of microgravity. Hand-eye motor coordination was studied in the 13 subjects participating in the experiment with five-day dry immersion who tracked the jumpy and smooth movements of a point visual stimulus (linear and pendulum-like; horizontal and vertical; circular, clockwise and counterclockwise). Ocular movements were recorded using binocular electrooculography; and manual motions were recorded using a joystick with a biological visual feedback, when one of the two stimuli on the screen showed the current joystick tilt. Computerized stimulation was provided using virtual reality goggles. The following parameters were evaluated: the latent and total reaction time; the amplitudes and velocities of the eye and hand movements; and the coefficients of effectiveness (amplitude ratio) and the gain (velocity ratio). The examinations were performed before immersion, after 3 h of immersion, on days 3 and 5 of immersion, during the first hours after the termination of immersion, and three days after the immersion (in all subjects); and on days 5–7 after the immersion (in four subjects). It was shown that support deprivation and minimization of proprioceptive afferentation affected ocular tracking to a larger extent than the accuracy of manual movements following the visual stimulus. It was found that, in all subjects, manual tracking, which did not significantly change during the test sessions, was more accurate than visual tracking; in contrast, the accuracy of visual tracking changed noticeably both in the course of dry immersion and after its termination.     

Visual-manual tracking and vestibular function during a seven-day dry immersion

A seven-day dry immersion experiment provided the opportunity to study the effects of decreased proprioceptive tactile and support afferentations on the vestibular function and visual-manual tracking. Before and after immersion, six subjects participated in a video oculographic evaluation of the static torsion otolith-cervicoocular reflex (OCOR) in response to head tilt by 30° in the frontal plane and dynamic vestibular-cervicoocular reactions to head longitudinal rotations at 0.125 Hz. In addition, the hand-eye motor coordination of tracking a jerky (sinusoidal) or smooth (linear) movement of point targets along the horizontal or vertical lines was evaluated on the basis of the data of electrooculography and records of manipulations with the joystick during immersion. A computerized test was performed in virtual glasses displaying images of visual stimuli and hand motor acts. The computed parameters included the reaction’s latent time, amplitude, speed and time of eye and hand movements, and gains of optooculomotor reactions and manual tracking as a ratio of eye/hand to visual stimulus speed. Testing was carried out before the experiment, after 3 h of immersion, on days 3 and 6 of staying in the bath, in the initial hours after immersion and on the third day of recovery. It was shown that removal of support and minimization of proprioceptive afferentation had a profound effect on the ocular tracking rather than pursuing the visual stimulus by hand. The accuracy of manual tracking was better in comparison with the eye tracking in all subjects. This was the first observation of changes in the peripheral vestibular system in two out of six subjects, i.e., inversion of the static torsion OCOP and positional nystagmus against a background of converted reflex, which did not change the parameters of the visual-manual tracking.     

Effect of real and simulated weightlessness on the characteristics of the static otolith reflex

To determine the role of the support-proprioceptive factor in functioning of the vestibular system, in particular, the role of static torsional otolith-cervical-ocular reflex (OCOR), the latter was studied in 16 subjects after a seven-day “dry” horizontal immersion and in 14 cosmonauts after a prolonged exposure to weightlessness (for 126–195 days). OCOR was studied by the videooculography method during alternately tilting the head towards the right or left shoulder by an angle of 30° in the frontal plane before the flight and before immersion, as well as on days 1, 3, and 7 after the completion of the immersion experiment and on days 1 (2), 4 (5), and 8 (9) after the spaceflight. For the first time it was demonstrated that elimination of the support and minimizing the proprioceptive afferentation may lead to the absence or inversion of the static torsional OCOR, as well as to a positional nystagmus against the background of the inverted reflex. Comparison of OCOR in cosmonauts after prolonged exposure to weightlessness and in the subjects examined after immersion revealed similarity in this reaction. However, changes in OCOR after immersion were encountered only in 60% of the subjects, whereas after the spaceflight, in 90% of the cosmonauts examined. The post-flight changes in OCOR were more pronounced and long-lasting.     

A biochemical protocol for the isolation and identification of current species of Vibrio in seafood

AIMS: We report a biochemical method for the isolation and identification of the current species of vibrios using just one operative protocol. METHODS AND RESULTS: The method involves an enrichment phase with incubation at 30 degrees C for 8-24 h in alkaline peptone water and an isolation phase on thiosulphate-citrate-salt sucrose agar plates incubating at 30 degrees C for 24 h. Four biochemical tests and Alsina's scheme were performed for genus and species identification, respectively. All biochemical tests were optimized as regards conditions of temperature, time of incubation and media composition. The whole standardized protocol was always able to give a correct identification when applied to 25 reference strains of Vibrio and 134 field isolates. CONCLUSIONS: The data demonstrated that the assay method allows an efficient recovery, isolation and identification of current species of Vibrio in seafood obtaining results within 2-7 days. SIGNIFICANCE AND IMPACT OF THE STUDY: This method based on biochemical tests could be applicable even in basic microbiology laboratories, and can be used simultaneously to isolate and discriminate all clinically relevant species of Vibrio.     

Analysis of the interdependence of temperament, neuroendocrine control, and psychophysiological state during dry immersion

The interdependence of temperament and the hormonal and psychophysiological states was investigated in eight young volunteers during seven-day dry immersion (DI). The levels of insulin and sex, steroid, and thyroid hormones in the blood and the psychomotor parameters were determined on days 3 and 7 of DI and on day 7 of recovery. Before DI, the volunteers filled in Cattell’s personality questionnaire. During DI, anxious subjects spent less time to compare visual patterns, demonstrating a stably high speed of reactions with a slight quality loss. Extraverts showed a high speed of reactions and stability of psychomotor parameters without an increase in the number of errors. Easy-tempered and introvert subjects retained inherently high insulin concentrations in DI. Support deprivation was accompanied by the drop of the triiodothyronine and cortisol levels and an increase in prolactin and thyroxin. The results of multiple correlation analysis led to the conclusion that DI emphasizes the role of original extra-introversion and dampers the original anxiety. Success can be attained by adequate alteration of the levels of steroid and thyroid hormones with effectively balanced vagoinsulin—sympathoadrenal neuroendocrine control and monoaminergic CNS activity.     

The oxidant-antioxidant equilibrium,activities of selected lysosomal enzymes and activity of acute phase protein in peripheral blood of 18-year-old football players after aerobic cycle ergometer test combined with ice-water immersion or recovery at room temperature

The goal of the study was to evaluate the effect of an aerobic exercise bout followed by ice-water immersion or recovery at room temperature on the redox state, activities of selected lysosomal enzymes and activity of α1-antitrypsin (AAT) in the blood of healthy sportsmen. Eleven amateur football players aged 18 were randomly assigned to two similar 30-min aerobic cycle ergometer tests followed by a recovery at room temperature (20 °C; Experiment 1) or ice-water immersion (3 °C, 5 min; Experiment 2). Peripheral blood was collected three times during both study experiments: before (baseline), as well as 20 and 40 min after the recovery or immersion. The concentrations of thiobarbituric acid reactive substances in blood plasma (plTBARS) and erythrocytes (erTBARS) were measured. The erythrocytic activities of superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPx) were also determined. In the blood serum, the activities of acid phosphatase (AcP), arylsulphatase (ASA), cathepsin D (CTS D) and AAT were evaluated. The activities of AcP, ASA, CTS D and AAT changed similarly during both experiments. The GPx activity decreased 40 min after the exercise/recovery compared to the baseline activity and was lower than 40 min after the exercise/immersion. The exercise followed by the recovery or immersion had no significant effect on the serum lysosomal and AAT activities in the studied men. The exercise/recovery reduced the hydrogen peroxide concentration in the men's erythrocytes, however the exercise/immersion demonstrated the opposite effect.     

Optimization of a working cryopreservation protocol for Pinus patula embryogenic tissue

Summary The protocol currently used to cryopreserve Pinus patula embryogenic tissue was investigated in an attempt to improve and optimize the recovery of tissue. This investigation describes two aspects that influence tissue recovery after cryopreservation: (i) the effects of precooling tissue prior to immersion into liquid nitrogen; and (ii) whether the choice of supports onto which the recovered tissue is suspended improved the recovery rate. Results indicated that precooling tissue to −70°C prior to immersion into liquid nitrogen was superior to precooling to −30°C or direct immersion in liquid nitrogen (−196°C). Tissue recovery improved when polyester grids were used as supports, and was slowest on filter paper supports.     

Post-hatching dynamics of plasma biochemistry in free-living European starlings (Sturnus vulgaris)

This is the first study of plasma biochemical parameters in free-living altricial birds during an entire developmental period in a nest, represented by European starling (Sturnus vulgaris). Dynamics of postnatal changes from hatching until close to fledging (days 1 to 15) were registered. Parameters of protein metabolism represented by total proteins, albumin and globulin concentrations increased continuously during the observed developmental period. There were two peaks in uric acid concentration on days 5 and 11. To the contrary, the creatinine content did not change throughout the observed period and increased only on day 15. Creatine kinase activity gradually increased until day 11 and then fell before fledging. Parameters of lipid metabolism (concentration of total lipids, triacylglycerols and nonesterified fatty acids) in plasma increased gradually reaching a plateau between days 8 and 11 and then declined on day 15. The cholesterol concentration pattern was similar to maximum value on day 11, then consecutively decreased. Concentration of glucose increased until day 8 and remained unchanged until fledging. Whereas calcium reached the highest concentration during days 8 and 11, phosphorus peaked earlier on day 5. The activity of alkaline phosphatase was similar to the pattern found in calcium concentration. Presented data showed an increase in both protein and lipid metabolism during the phase of rapid growth. A remarkable decrease in parameters of lipid metabolism before fledging may reflect increased physical activity and changes in nutrition.     

Screening and Assessment of Selected Chilli (<i>Capsicum annuum</i> L.) Genotypes for Drought Tolerance at Seedling Stage

This study was undertaken to investigate oxidative stress tolerant mechanisms in chilli (Capsicum annuum L.) under drought genotypes through evaluating morphological, physiological, biochemical and stomatal parameters. Twenty genotypes were evaluated for their genetic potential to drought stress tolerant at seedling stage. Thirty days old seedlings were exposed to drought stress induced by stop watering for the following 10 days and rewatering for the following one week as recovery. Based on their survival performance, two tolerant genotypes viz. BD-10906 and BD-109012 and two susceptible genotypes viz. BD-10902 and RT-20 were selected for studying the oxidative stress tolerance mechanism. Drought reduced root and shoot length, dry weight, ratio, petiole weight and leaf area in both tolerant and susceptible genotypes, and a higher reduction was observed in susceptible genotypes. Lower reduction of leaf area and photosynthetic pigments were also found in tolerant genotypes. Moreover, tolerant genotypes showed higher recovery than susceptible genotypes after the removal of stress. A higher reduction of relative water content (RWC) may cause an imbalance between absorbed and transpirated water in susceptible genotypes. Higher accumulation of proline in tolerant genotypes might be helpful to for better osmotic maintenance than that in susceptible genotypes. Tolerant genotypes showed higher antioxidant activity as they showed DPPH radical scavenging percentage than the susceptible genotypes. Moreover, closer stomata in tolerant genotypes than susceptible ones helped to avoid dehydration in tolerant genotypes. Thus, the above morphological, physiological, biochemical and stomatal parameters helped to show better tolerance in chilli under drought stress.     

Serum creatine kinase levels and the number of sarcolemmal dystrophin disruptions in human skeletal muscle fibers under conditions of 7-day "dry" immersion

9 male volunteers took part in the experiment. They were divided in two groups. 5 volunteers (control group) have been in "dry" immersion for 7 days. 4 volunteers (stimulated group) in addition to "dry" immersion were treated with artificial support stimulation. We investigated the number of muscle fibers with the disruptions of sarcolemmal dystrophin and serum creatine kinase levels. 7-day "dry" immersion does not change the mean number of muscle fibers with dystrophin disruptions, it leads to significant decrease of serum creatine kinase levels and does not influence on the sensitivity of sarcolemma to injury. Artificial support stimulation does not influence on these parameters.     

Growth and development of carnation ‘Dreambyul’ plantlets in a temporary immersion system and comparisons with conventional solid culture methods

The aim of the current study was to compare the effects of the culture method—conventional solid medium culture and temporary immersion system (TIS)—on the growth and development of carnation ‘Dreambyul’ plantlets. At the same time, different immersion intervals and immersion durations of TIS culture were also tested to find the optimal setting for mass production of high-quality carnation plantlets in vitro. In the first experiment, the results showed that the shoot length, root length, and number of nodes of plantlets cultured in the TIS were highest when the immersion interval was 8 h. Compared with that of plantlets cultured in the conventional solid medium culture, the fresh weight of plantlets cultured in the TIS was at least 3 times greater. The greatest total chlorophyll content, stomata with normal shapes was observed for plantlets grown in the TIS with an 8-h immersion interval. The lowest H₂O₂ level was recorded in plantlets cultured with the 8-h immersion interval. In the second study, growth traits such as the shoot length, root length, and stem diameter, as well as the number of shoots and roots tended to increase with immersion durations, and reached their peaks when the immersion duration was 90 s. Excessive water accumulation in tissues and a higher incidence of hyperhydricity were observed in plantlets where the immersion duration was 120 and 150 s. These findings suggest that an immersion interval of 8 h, combined with an immersion duration of 90 s, could be the optimal setting for growth and development of carnation ‘Dreambyul’ plantlets cultured in the TIS.