Influence of a 1000 Times Weakened Magnetic Field on Embryogenesis and Ontogenesis of the Japanese Quail in Several Generations

The paper presents experimental data on the influence of a 1000-fold weakening of the Earth's magnetic field on the embryonic and postembryonic development of the Japanese quail in three generations. It has been shown that the weakening of the earth's magnetic field by a factor of 1000 affects the formation of blood vessels in Japanese quail embryos, in particular, causing a decrease in angiogenesis in seven-day-old embryos of both the first generation (F₁) and the next two ones (F₂ and F₃). Pathological and anatomical studies of embryos of different ages in three generations have revealed various pathologies associated with vascular system disorders, as well as disorders in the development of the beak and eyes. In the ontogenesis of F₃ quails, there is a decrease in the hatchability of chicks.

Photoinduced changes in subcellular structures of the retinal pigment epithelium from the Japanese quail Coturnix japonica

Fifteen-week-old sexually mature female Japanese quails (Coturnix japonica) grown under various lighting conditions were used in the study. It was found that the number of mitochondria and phagosomes was increased by 1.5-fold in the retinal pigment epithelium from birds reared for 95 days under blue light (440-470 nm) vs. reduced blue light component conditions. Also, it was found that egg production was increased by 15% in birds reared under blue light compared to other lightning conditions. Thus, we concluded that blue light conditions resulted in elevating metabolic activity and accelerating pace of life in Japanese quails. It is assumed that the blue light-induced effects are probably due to inhibition of melatonin synthesis.

[EFFECTS OF HYPOXIA AND GROWTH FACTORS ON THE ANGIOGENIC ACTIVITY OF MULTIPOTENT MESENCHYMAL STROMAL CELLS]

The effects of fetal calf serum (FCS) growth factor concentration and cell growth phase on production of angiogenic mediators by mesenchymal stromal cells (MSCs) at different O2 levels (20 and 5%) was studied. For this purpose vascular endothelial growth factor (VEGF-A) production was measured in MSC-conditioned medium (CM); besides, branching vessels as well as vessel end points (ramification) in the chorioallantoic membrane of Japanese quail eggs (Coturnix coturnix japonica) were counted following MSC-CM application. During the standard cultivation (20% O2; 10% FCS) the total number of vessels was 1.6 times higher comparing with hypoxic condition (5% O2; 10% FCS) due to increase in ramification, the number of branching vessels did not change. Maximal (double) increase in the total vessel number was observed when CM from MSCs after hypoxia plus serum deprivation was added. VEGF-A synthesis linearly increased with FCS concentration both at 20% and 5% O2. In all cases VEGF-A level was higher at hypoxia. No direct correlation between the VEGF-A concentration and total number of vessels was noted indicating that hypoxia possibly stimulates synthesis of additional angiogenic factors to enhance vascular growth despite the drastic serum deprivation. At 20% oxygen, exponentially growing MSCs showed the highest angiogenic activity and the ramification increased in 1.6 times. Depending on O2, MSCs produced angiogenic factors required at different stages of vascularization. Specifically, mediators of ramification were accumulated in the standard conditions (20% O2) and factors stimulating growth of branching vessels--in hypoxia.

[TESTING THE PROTECTIVE PROPERTIES OF ARGON DURING SUBACUTE EXPOSURE TO HYPOXIC HYPOXIA]

Previously it has been shown that argon has a stimulating effect on biological processes including, specifically, strong protective properties during exposure to acute (1-4 hrs.) hypoxic hypoxia. Experiments with animals under hypoxia gradually growing over 3 to 7 days may give insight into mechanisms of the argon protective action. Purpose of the work was to explore character and severity of developing disorders, to attempt their prognosis and to test potentiality of argon as a protector from the effects of subacute hypoxic exposure. In two series of experiments Wistar male rats were housed in pressure chambers with different rates of O2 reduction without argon and with argon in concentration of 32-38%. Oxygen reduction from 20.9 to 9.0% in 3 days led to the death of 50% animals. Oxygen reduction to 12.0% in 7 days and one day in low-oxygen atmosphere was harmless for animals. Argon in air makes the response to hypoxia almost twice as sharp on virtually every level (red blood system, physiological, morphological and biochemical shifts) validating the concept that argon acts as a stimulator. In context of the most critical processes of adaptation to hypoxia--activation of blood formation and lipid metabolism--this sharpening of the response results in depletion of body resources and instigates irreversible shifts.

[Embryogenesis of the Japanese quail in hypomagnetic conditions applied to deep space flights]

During future interplanetary flights and on the lunar base, astronauts and bioregenerative systems on the space ship will occur in an interplanetary magnetic field, which is much lower than the habitual geomagnetic field (GMF). It is known that hypomagnetic conditions have an adverse biological effect on human beings and other living systems. In our research the Japanese quail has been chosen as one of the possible elements of the bioregenerative live support system. The magnetic system--Helmholtz's coils--is used for compensation of GMF. The GMF in the center of Helmholtz's coils was decreased to 80-100 times. The eggs were kept under hypomagnetic conditions for 4 and 10 days in a special nonmagnetic incubator. The experiments have demonstrated a negative influence of hypomagnetic fields on the embryo development of the Japanese quail. One of the possible ways to solve the problem consists in installing special magnetic systems onboard the interplanetary ship and a lunar base. Evidently, it is necessary to create an analogue of GMF for bioregenerative live support systems.

[Development of paste-type food for experiments with mice onboard unmanned spacecrafts]

One of the crucial issues of handling animals in space flight is availability of food and water supply systems. However, water supply for animal experiments onboard unmanned spacecrafts is a particularly formidable problem. To maintain laboratory mice in space flight, a paste-type food was formulated on the basis of the standard extruded combined food for laboratory rodents (PK-120) with a 18.3% wet protein content and moisture raised to 68%. Food manufacturing technology for rodents reproduces essentially the one for quails that had shown good advantages in an experiment with adult birds aboard orbital complex Mir. The proposed food was tested with white laboratory mice (males and females) of mature 37-d age. According to the data of blood clinical analysis and visceral organs morphology investigations, feeding with the paste-type food without additional water over 21 days did not change the life weight of mice or food digestibility and availability. These biological test results gave go to feed mice in the Bion-M1 and synchronous ground experiments with the paste-type food.

[Comparative evaluation of the effects of hypoxic gaseous mixtures varying in oxygen concentration on Japanese quail embryogenesis]

The paper presents the results of comparative characterization of the effects of low oxygen levels (10 ± 0.5 and 14.5 ± 0.5%) on developing organism. Four-day old embryos of the Japanese quail (Coturnix coturnix japonica) were chosen for the object of investigation as this is the age when avians acquire their organs and systems. Acute hypoxia (10 ± 0.5% oxygen) caused a general death of the embryos, and serious abnormalities of the eye and brain, and ectopy. Embryos that developed in the low-oxygen atmosphere (14.5 ± 0.5%) did not exhibit many of these morphological abnormalities and yet their growth was retarded apparently. Such abnormalities in acute hypoxia are ascribed to disturbance in development of extra-embryonic membranes, amnion in particular, desynchronization of morphogenetic processes and movement of embryo's tissue layers.

[Histogenesis of Japanese quail bone and cartilage tissues at the final stages of embryonic development in microgravity]

The article reports the results of comparative histological studies of skeleton development in 14- and 16-day Japanese quail embryos grown in space flight and in the 1-g gravity. The investigation revealed retardation of cartilage replacement by bone in the femur and tibia in space embryos as compared with their controls. Perichondral ossification metaphysis was reached by day 14 both in the space and control embryos. Destruction of cartilaginous diaphysis advanced onto the proximal and distal parts including the periphery. Tibia and femur cartilaginous cores in space embryos were destructed worse than in the controls in consequence of insufficient minerals supply. Perichondral ossification in the 16-day space and control embryos was alike close to completion spreading as far as the epiphysis. Long bones metaphysis was abundant in monomorphic cells as a growth bank existing during and 7 days post hatching. However, absence, in contrast to the controls, of osteogensis sites in long bones epiphysis, suggested retardation of chondrocytes calcification in these areas, as well as of ossification in space embryos.

[Spinal marrow development in Japanese quail embryos and chicklings in the spaceflight environment]

Results of studying spinal marrow histogenesis in age varying Japanese quail embryos and chicklings whose embryonic development took place in microgravity are presented. Histological comparison of spinal cords showed retardation of morphogenetic development, lumber spine especially, in the group of flight embryos manifested as incomplete proliferative activity during migration processes and nervous cell differentiation. Like on earth, in space microgravity chicklings also hatched on day 17 of embryogenesis. Multiform marrow changes in space chicklings were a nervous cells reaction to the functional state of organism in the micro-g environment.

[Early bone and cartilage histogenesis in embryonic Japanese quails in the conditions of microgravity]

The article presents the results of a comparative histological investigation of skeletal bones genesis in Japanese quail embryos developed in the spaceflight microgravity (space group) and laboratory (control group). Total preparations of 4-day-old embryos from both groups demonstrated clearly that the cartilaginous anlage of the femoral bone had central, dyaphisial, 2 epiphysial and 2 proliferation zones. By day 7 of embryogenesis, cartilaginous anlages had grown in size in both groups due to intensive chondrocytes multiplication and gain in the intercellular substance mass. Tibial cuff in space embryos measured half and femoral cuff was 2.3 times smaller in comparison with these parameters in the control group. In addition, intensity of chondrocyte multiplication was reduced Histological profiles of the femur and tibia in 10-day old embryos of the control pointed to enhancement of osteogenesis. The metaphysis zone contained distinct mitosis figures on different stages of division. Bone deposition could be seen below the peristoma. The osteogenesis cuff spread up to the femoral anlage metaphysis; cartilage was calcined. Space embryos display retard osteogenesis. There were ingrown blood vessels in the region of cartilage destruction; however, vessels grown in the periosteum were less in number as compared with the laboratory control. Also, the perichondral ossification layer was considerably thinner, whereas the osseous cuff was 1.3 and 1.45 times shorter in the femur and tibia, respectively. To sum up, the histological investigation of bones from 4-, 7- and 10- day old Japanese quail embryos demonstrated retardation of osteogenesis in the conditions of microgravity.

[Histogenesis of the liver of Japanese quail embryos developed in the conditions of microgravity]

The article reports the results of histogenetic studies of the liver extracted from Japanese quail embryos and hatchlings that had passed the embryonic and postnatal development in microgravity. Comparison of the liver from the flight and laboratory embryos showed identity of organogenesis and histogenesis processes in space and on Earth. However, it should be noted that early histogenetic development of the space embryo liver had been retarded which was concluded from an enlarged lumen in bile capillaries and loose arrangement of epithelium girders as compared with the control On day-10 post flight, the flight embryos exhibited liver induration through narrowing of sinusoids lumen. Haemopoietic zones became less numerous. By the end of embryonic development these histological differences of the flight and control liver disappeared essentially. Organogenesis and histogenesis of the liver obtained from the hatchlings that had spent 5 days in microgravity did not depart from the norm. However, inability of the birds to adapt to microgravity and ensuing starvation was the reason for dystrophic changes in the liver, venous congestion and increased histoleucocytic activity. All the liver changes faded away soon alter the hatchlings were settled in favorable life conditions

[Histogeny of the visceral organs of embryonic Japanese quails developed in the micro-g environment]

The paper reports the results of organogenic and histogenic investigations of the visceral organs of embryonic Japanese quails incubated in the microgravity aboard orbital complex Mir. Investigations of the gastrointestinal tract failed to reveal macrodeviations in the organs' structure, differentiation of layers or cells along the full length of the entodermal canal. However, comparison with the ground controls exhibited poor development of stromal connective tissues in the flight embryos evidencing loose arrangement and small number of fibers. Local hyperplasia in the duodenal epithelium was due to the proliferation rather than differentiation processes; it could affect food intake and parietal digestion in the flight chicks. Though the Japanese quail embryos developed in space microgravity had some deviations, their digestic apparatus was mature to uptake and assimilate food.

[Effect of hypoxic argon-containing gas mixtures on developing organism]

Experimental data on the impact of argon-containing hypoxic breathing mixtures on the early embryonic growth of Japanese quail (Coturnix coturnix japonica dom.) are presented. The results showed that after 4-day incubation of eggs in an oxygen-nitrogen breathing mixture (13.8-15.0% O2, 86.2-85.0% N2) only 16.7% embryos reached the stage of 3.5-d development. Introduction in the hypoxic mixture of argon (55% of the total volume) increased the number of embryos on the stage of 3.5-4 day of normal morphological development to 60%. It became evident from the analysis that embryos developed in the O2-Ar-N2 hypoxic mixture had 25% less pathologies as compared with embryos developed in a largely nitrogen-containing gas mixture. Hence, we received the experimental evidence that 55% of argon in a hypoxic breathing mixture with up to 15% of oxygen is favorable to the early embryonic growth of Japanese quail stimulating metabolic processes in germ organism.

[Development of chow for Mongolian gerbils suitable for the conditions of space flight]

One of formidable issues of experiments with animals in space flight is water supply. For Mongolian gerbils (Meriones unguiculatus), classed as cricetid rodents, water in chow is enough. These animals are a new object for space biology. Our purpose was to compose a full-value formula and design a chow making and long-term storage technology to provide Mongolian gerbils for in microgravity. The chow is required to have a 28-d shelf life. To assess the chow suitability on autonomous space fight, the gerbils we house in a cage with the geometry reproducing the current design of the future space animal module. The assessment was performed with adult male gerbils weighing 50.5 +/- 3.4 g on the average. The animals ate up 40.1 +/- 3.9%, i.e. less than 50% of the feed all through the period of experiment. However, by the end of the experiment the body mass and exterior remained essentially unchanged In was concluded that the chow formula can be prescribed to Mongolian gerbils housed in self-contained modules.

[Physiologically active argon-based gas mixtures as a means of creating fire-safe gaseous environments in pressurized modules of varying purpose]

Development of acute hypoxic hypoxia in consequence of fire in various pressurized modules was studied. The investigation was aimed to look into the effects of inert argon and dramatic oxygen reduction in gaseous environment on animals (Wistar rats, mice c57bl/6, balb/c and f1cbaxbalb/c hybrids, Japanese quail embryos) and microorganism (Escherichia coli strains k-12 jf 238 and k-12 jm 83). Also, inflammability of some widely used materials was assessed in order to provide inputs to developers of fire-safe gaseous mixtures for pressurized habitats. It was shown that argon is favorable to survivability of animals and to maintenance of a high level of oxygen consumption. Gaseous mixtures with oxygen content less than 15 volume % suppressed burning of selected materials. Results of the investigation offer possibilities for designing new hypoxic fire-safe gas mixtures that will provide adequate human performance and ensure survival in extreme situations.

[Effect of krypton-containing gas mixture on Japanese quail embryo development]

Investigated were effects of gas mixture with up to 3.0 kgs/cm2 of krypton on the embryonic development of domesticated Japanese quail (Coturnix coturnix japonica dom.). Results demonstrated absence of a serious krypton effect on Japanese quail embryos. Development of embryos proceeded in due course; morphometrically the experimental embryos were essentially similar to controls. It should be noted that despite exposure to acute hypoxic hypoxia during the initial 12 hours of development in the krypton-containing gas mixture, viability of quail embryos was high enough which can be ascribed to the krypton protective action. Besides, an additional experiment showed that krypton partial pressure of 5-5.5 kgs/cm2 produces the narcotic effect on adult Japanese quails.

[Prenatal acoustic stimulation and feeding behavior of Japanese quail chicks (Coturnix coturnix japonica)]

Effects of a prenatal rhythmic tone on behavior of Japanese quail chicks were studied on the next days after hatching. The acoustically stimulated chicks demonstrated a significantly more frequent following response, feeding reaction and comfortable behavior when hearing the tone as compared with their controls. Bandwidths stimulating this or another behavior were determined.

[Impact of hypoxic gas mixtures on embryogenesis of the Japanese quail]

Avian embryogenesis is of great interest to investigators, as the germ developing outside mother's body, is capable to react briskly to any alteration in the outer world. The paper present experimental evidence of the impact of oxygen with physical and chemical properties modified by short-cycle no-heating adsorption (SNA) in a hypoxic gas mixture (10% O2) on the early embryogenesis of the Japanese quail. Low concentrations of oxygen are known to be a dramatically disturbing factor for embryo's morphology. It was demonstrated experimentally that four days before incubation bird are highly sensitive to oxygen deficiency which is responsible for developmental abnormalities. The use of SNA oxygen reduced the frequency of pathologies in the Japanese quail germs as compared with their controls incubated in gas environment containing medical oxygen generated by low-temperature rectification.

[Effect of chronic exposure to low doses of ionized radiation on embryonal development of the Japanese quail]

Experiments on Japanese quail embryogenesis on a background of chronic exposure to gamma- and neutron doses comparable with the doses of ionized radiation inside the orbital space stations Mir and ISS, and exploration vehicles gave evidence that permanent absorption of low gamma-doses (0,15 cgy/d) did not impact development of the Japanese quail embryos. On the contrary, the neutron dose of 200 microgy/d imparted by the neutron flux of 30 particles/cm2s was hazardous to embryos as it caused morphological disorders in 12% of embryos.

[Studies of the eating behavior of Japanese quail chicks in the early postnatal period]

Time of the eating reaction (response to video signals) and eating behavior shortly after hatching were studied in Japanese quail chicks whose embryonic development took place under normal or changed gravity. Chicks partially incubated in a changed gravity showed a much slower eating reaction when compared with the chicks the prenatal development of which occurred under the normal gravity. In the chicks incubated at 1 g and placed in individual cages immediately after dominating afferentation for the eating behavior was visual Observations in the study will be used as a basis for designing a technology for handling and maintenance of hatchlings of the Japanese quail as a potential heterotrophic component of space life support systems.

Post-embryonic development of chicks of the Japanese quail under conditions of the limited volume

According to our results, chicks of the Japanese quail can survive within the first 10 days of a life under conditions of the limited volume when their mobility is completely limited. However, their development was impaired in comparison with chicks housed in the common cages. Besides, the delay in development of chick's plumage has been observed. The analysis of body mass in test groups has shown that practically all chicks were smaller than chicks from control group. It is the result of feed consumption decrease (about 30% from control group) caused by the restriction of mobility of chicks. But after their transferring to the common cages at the end of the experiment, body mass in test group rapidly reached the level of body mass in control group. Research has shown that percent of alive of quail chicks maintained in the chamber of animals of complex "Incubator-2", was higher than in first two experiments. Therefore, works on improvement of devices for the maintenance of quail chicks continue, and also new adaptations develop for the maintenance of chicks in their early post-embryonic period (till 10 days) with reference to conditions of weightlessness.

[Morphological changes in the adrenal gland of Japanese quail chicken hatched out in microgravity]

The paper presents results of studying effects of spaceflight factors on the adrenal structure in Japanese quail hatchlings (Coturnix coturnix japonica) incubated and kept alive 4 to 5 days aboard the space station Mir. In comparison with the ground controls, cortical cells in the adrenals of space hatchlings contained copious fat drops, mitochondrias, and significantly dilated cisterns of the endoplasmic reticulum. Accumulation of fat drops evidences lowered cholesterol transformation and disturbed genesis of steroids. Cytoplasm of the medullar chromaffin cells was full of dark large granules; some of these cells also had enlarged mitochondrias and dilated endoplasmic reticulum cisterns.

[Peculiarities of eye morphogenesis in embryonic Japanese quails developed in microgravity]

This work is a part of comprehensive research into the effects of space flight on Japanese quail ontogenesis. Analysis of eye morphogenesis in the embryonic Japanese quails developed in microgravity discovered considerable deviations and abnormalities. Ocular abnormalities in the embryonic quail were mainly micro-ophthalmic and associated with disproportional growth of the pigmental epithelium and neural retina which resulted in plication and a broken sandwich structure of the retina.

[The effect of argon-containing hypoxic gas environment on development of Japanese quail embryos]

In case of acute hypoxic hypoxia argon in the gas environment is favorable to survivability of laboratory animals (rats). Our purpose was to evaluate effects of an argon-containing hypoxic gas environment on embryogenesis of the Japanese quail (Cortunix cortunix japonica). Eggs of the Japanese quail were incubated in a pressurized chamber with a hypoxic gas environment differing in concentration of nitrogen and argon. In hypoxic (10% O2) oxygen-nitrogen and oxygen-nitrogen-argon atmospheres total mortality of embryos was observed no later than on day 7 of development. These gas mixtures also had a teratogenic effect. However, about 55% of argon in atmosphere prevented completely microcephalia and reduced in half incidence of other pathologies.

[Morphological study of gastrocnemius muscle in Japanese quail chicks hatched out in space flight]

Slovak experiment Quail SK-6 aboard orbital station Mir in the period of February 20-27, 1999 resulted in hatching out of viable chicks of the Japanese quail. The paper presents morphologic results of investigation of m. gastrocnemius of the chicks after 4-5-d life in space microgravity. On the whole, histologically the gastrocnemius of the space chicks was very much similar to that of the control group. Muscular fibers were, which is typical, striated; bundles of myofibrills and numerous nuclei were on the periphery of the fiber under the sarcolemma. However, despite the similarity of the muscular histology, the chicks borne and exposed in microgravity displayed some deviations in the gastrocnemius as compared to their controls. Thus, Z-lines in some of the muscular fibers had a zigzag form or were doubled. In places, mitochondria were increased in size and lined up in chains longer than a sarcomere; internal membranes of the mitochondria were thickened and vacuolized, there were expanded tubules in the sarcotubular apparatus, and muscular fibers with multiple fatty vacuoles.

Launch conditions might affect the formation of blood vessels in the quail chorioallantoic membrane

As a part of the first joint USA-Russian MIR/Shuttle program, fertilized quail eggs were flown on the MIR 18 mission. Post-flight examination indicated impaired survival of both the embryos in space and also of control embryo exposed to vibrational and g-forces simulating the condition experienced during the launch of Progress 227. We hypothesized that excess mechanical forces and/or other conditions during the launch might cause abnormal development or the blood supply in the chorioallantoic membrane (CAM) leading to the impaired survival of the embryos. The CAM, a highly vascularized extraembryonic organ, provides for the oxygen exchange across the egg shell and is thus pivotal for proper embryonic development. To test our hypothesis, we compared angiogenesis in CAMs of eggs which were either exposed to the vibration and g-force profile simulating the conditions at launch of Progress 227 (synchronous controls), or kept under routine conditions in a laboratory incubator (laboratory controls). At various time points during incubation, the eggs were fixed in paraformaldehyde for subsequent dissection. At the time of dissection, the CAM was carefully lifted from the egg shell and examined as whole mounts by bright-field and fluorescent microscopy. The development of the vasculature (angiogenesis) was assessed from the density of blood vessels per viewing field and evaluated by computer aided image analysis. We observed a significant decrease in blood-vessel density in the synchronous controls versus "normal" laboratory controls beginning from day 10 of incubation. The decrease in vascular density was restricted to the smallest vessels only, suggesting that conditions during the launch and/or during the subsequent incubation of the eggs may affect the normal progress of angiogenesis in the CAM. Abnormal angiogensis in the CAM might contribute to the impaired survival of the embryos observed in synchronous controls as well as in space.

Functional development of small intestine of Japanese quail hatched on MIR orbital station

The effect of microgravity on functional development of the small intestine of Japanese quails incubated for 2-3 d and hatched on the orbital station MIR was examined. After 5 d of space flight duodenal and jejunal alkaline phosphatase (AP) activity of the experimental group was compared with the AP activity in quails of the same age hatched on the Earth (laboratory controls). Short-term microgravity leading to decreased food intake resulted in significant increase of AP activity in both duodenal and jejunal enterocytes (P<0.001) of the experimental quails. The results suggest that increased AP activity probably reflects the delayed functional development of the small intestine as a consequence of inappropriate food intake during non-physiological conditions of space flight.

Main characteristics of biological components of developing life support system observed during the experiments aboard orbital complex MIR

Since 1990, the orbital complex MIR has witnessed several incubator experiments for determination of spaceflight effects on embryogenesis of Japanese quail. First viable chicks who had completed the whole embryological cycle in MIR microgravity hatched out in 1990; it became clear that newborns would not be able to adapt to microgravity unaided. There were 8 successful incubations of chicks in the period from 1990 to 1999. In 1995-1997 the MIR-NASA space science program united Russian and US investigators. As a result, experiments Greenhouse-1 and 2 were performed with an effort to grow super dwarf wheat from seed to seed, and experiment Greenhouse-3 aimed at receiving two successive generations of Brassica rapa. But results of these experiments could not be used for definitive conclusions concerning effects of spaceflight on plant ontogenesis and, therefore, experiments Greenhouse-4 and 5 were staged within the framework of the Russian national space program. The experiments finally yielded wheat seeds. Some of the seeds was left on the space station and, being planted, gave viable seedlings which, in their turn, produced the second crop of space seeds.

[Thyroid gland development in Japanese quail embryos incubating in microgravity]

The investigation of the progress of thyroid prenatal development in the Japanese quail has been first performed in the MIR microgravity environment. Development of thyroid glands in control and flight embryos was shown to pass same stages (trabecular and follicular). However, the flight embryos demonstrated retarded a development of the gland as compared to the control one. Slowing-down of thyroid organogenesis in the flight embryos is evidently related to retardation in formation of their blood system and a consequent decrease in blood inflow to the thyroid microcirculatory bed.

[Biological life support systems: investigations on board of orbital complex "Mir"]

From 1989 till 1998 twelve experiments were performed by Bulgarian, Russian, Slovak, and US researchers and engineers on the effects of space flight on the model of ecosystem "algae-fishes-bacteria", and ontogenesis of birds (Japanese quail) and higher plants. For the first time several viable chicks were hatched and passed the whole cycle of their embryonic development in the MIR microgravity. The length of the plant ontogenetic cycle as a whole and its specific stages appeared to be same as on Earth. Seeds of Brassica rapa gathered and planted in greenhouse Svet on board MIR yielded robust shoots. Photosynthesis and dark respiration of plants growing in spaceflight were successfully measured.

[Influence of hypodynamia on organism of Japanese quail]

The present study is a part of a more comprehensive investigation of the spaceflight effects on ontogenesis of the Japanese quail. Reported are data about the effects of a 33-day immobilization on behavior, physiology and the reproductive function of these birds. As was revealed in the experiment, immobilization reduces the mass of the quail body and leads to a number of reversible disorders in the reproductive function including a sharp decrease in oviposition in females and disturbances in spermatogenesis in males.

[Characteristics of morphogenesis of the Japanese quail embryos during microgravity]

Experiments performed in the period of 1995-1996 cooperatively with US investigators within the MIR/SHUTTLE and MIR/NASA space science projects continued exploration of avian embryogenesis in microgravity. Evaluation of Japanese quail embryos incubated in spaceflight microgravity showed that for the most part they were normally developed and compliant with duration of incubation. One of the major morphometric characteristics of embryo are its mass and size. Comparative analysis of body mass values in the space and laboratory and synchronous control groups pointed to a slight retardation. Body length of space embryos mimicked their mass curve. Data on the dynamics of mass and length of Japanese quail embryos support the well-known theory according to which growth and formation are distinguished by equifinality. No differences were revealed by the investigations of individual parts of embryonic bodies in the space and control groups. However, this finding was true only with regard to the embryos that had no developmental abnormalities. A part of embryos had defective eyes (microphtalmia), limbs (twisted fingers), and beaks.

[The vestibular apparatus of quail embryos in an experiment on the Kosmos-1129 biosatellite]

The light microscope was used to study serial sections of labyrinths of quail embryos incubated and reared during 12 d orbiting of Cosmos 1129. On recovery the embryos were aged 9, 11.5 and 12 days. No significant deviations in the development of the vestibular apparatus in flight species were noted as compared to the controls. Given this and our experimental data about in-space development of fish and amphibians we may deduce that hypo-g does not exert a noticeable altering effect on the vestibular embryogenesis. Nevertheless, it should be pointed out that in all otolith organs and semicircular channel ampules of the flight embryos cup-form neural endings innervating type I sensory cells were markedly swollen in contrast to the control. Earlier swollen cup-form nerve endings have been found in one adult rat after 7 days of space flight aboard Cosmos 1667. However, exposure in space does not bring about a substantial swelling of bud-like nerve endings which contact type II sensory cells. Thus, a conclusion may be drawn that spaceflight factors are liable to produce shifts in the type I sensory cell--cup-form nerve ending unit but they do not affect type II sensory cell--bud-like nerve ending unit to the extent when effects can be identified by light microscopy.

[Quantitative characteristics of cells formed during early postnatal ontogenesis in the cytoarchitectonic layers of the parietal region of the cortex in normal mice and following brain injuries]

By means of computer analysis, size distribution of neurons and glial cells together with the label of 3H-thymidin labelled cells were studied in cytoarchitectonic layers of the field 1 in the mouse parietal cortex injected with the isotope on the 5th day of life and killed 1 month later. In some animals, 3 days before 3H-thymidin injection, the parietal region in the right hemisphere was perforated. The labelled cells were subdivided into 2 groups according to their size: astrocytes (A) and small gliocytes (mg). Labelled A and mg were stated to be rather evenly distributed along the cytoarchitectonic layers in the field 1. The trauma performed resulted in increasing amount of the labelled A and MG in the operated hemisphere. Uniformity in distribution of the labelled A and mg, occupying the position of satellites, did not change considerably at the trauma, in spite of general quantitative increase of the labelled glial cells. One month after the trauma, body dimentions of the mice labelled with A and mg did not considerably differ from those of intact animals, while the size of nerve cells increased. Thus, neurons in the parietal cortex of a growing brain respond to brain trauma with hypertrophy of cell bodies, and glial populations--with increase of their number.

[Influence of intrauterine asphyxia on the development of spinal ganglia]

In 17- and 18-day-old rat embryos and in 10-, 30-day-old newborn rats, the development of the spinal ganglia neurons was investigated under normal conditions and after intrauterine asphyxia. It was stated that increase in the profile field of the neuronal body development proceded differently before and after birth. Before birth, the most intensive growth was noted in large ganglial cells, while after birth--in middle and especially small cells. It was stated that embryos subjected to asphyxia in the last fourth of their intrauterine life suffered from chronic disorders in their neuronal cells, their intensity increasing with time reaching maximum to the first month of life. This process involved mainly the cells of middle and small size.