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Fish scale is a calcified tissue that contains osteoblasts, osteoclasts, and bone matrix, all of which are similar to those found in mammalian bone. Recently, we developed a new in vitro model system using goldfish scale. This system can detect the activities of osteoblasts and osteoclasts with AlkaLine Phosphatase (ALP) and Tartrate-Resistant Acid Phosphatase (TRAP) as the respective markers and analyze the co-relationship between osteoblasts and osteoclasts. Using this system, we indicated that osteoblastic and osteoclastic activities in the scale responded to the simulated microgravity with a three-dimensional clinostat. As these activities in the scale did not change by the stimulation with a two-dimensional clinostat, we believe that the response to simulated microgravity in the scale osteoblasts and osteoclasts is a specific phenomenon. In addition, we analyzed the bone metabolism under 2-, 4-, and 7-gravity (G) loading with a centrifuge and compared them with the control (1-G). The osteoblastic activity significantly increased under 2- and 4-G loading. This activity increased remarkably under 7-G loading. On the other hand, we found that the osteoclastic activity significantly decreased under 2-G loading. Under 4-G loading, there was no significant difference between G-loaded scales and control scales. The osteoclastic activity tended to increase under 7-G loading. These results were similar to our previous study of acceleration by vibration. With the goal of developing a drug for bone diseases, the effect of novel bromomelatonin derivatives on osteoblasts and osteoclasts was examined. All bromomelatonin derivatives had an inhibitory action on osteoclasts. In particular, 1-benzyl-2, 4, 6-tribromomelatonin (benzyl-tribromomelatonin) possessed a stronger activity than melatonin. In reference to osteoblasts, all bromomelatonin derivatives had a stimulatory action. In addition, estrogen receptor mRNA (messenger Ribonucleic Acid) expression (an osteoblastic marker) was increased in benzyl-tribromomelatonin (10(exp -7) M)-treated scales. Therefore, this chemical will be useful to treat bone diseases, such as those experienced in space flight., 資料番号: AA0063706059

To investigate the relationship between gravity and the thyroid hormone on the pituitary-thyroid axis of amphibians, we raised frogs, Xenopus tropicana under hypergravity (5G) environment and gave thyroxin from St58 to St 59-60. The development of the frog was delayed under hypergravity condition. The total volume, cell size and cell number were reduced in pituitary, thyroid and cerebellum of hypergravity treated frogs. On the other hand, the morphological malfunctions of the treated frogs were recovered by the administration of thyroxin. These changes indicate that the drug recovers the declined functions. These results suggest that the thyroxin therapy rescues the hypofunction and dysfunction of the pituitary-thyroid axis from hypergravity., 資料番号: AA0063706064

Effects of hyper gravity (3G) on mouse behavior were examined. Mature mouse exposed to 3G initially showed smaller amount of food consumption, short feeding period and weight loss. Four days after exposure started, feeding period increased and at the same time food intake and body weight also increased. These results suggest that little food intake and loss of weight may be due to the appetite suppression. Compared to the mouse under 1G environment, 3G mouse showed 'pressed' posture. We employed the bend angle of the back of the mouse as the index of the posture. Then back angle decreased immediately after exposure to hyper-gravity and recovered within four days. It was likely that posture recovered because body load is reduced by decreasing weight. The mouse under 3G environment also exhibited little horizontal and vertical movement. These parameters didn't increase until 10 days from the onset of exposure. Thus, it could be assumed that increase of movement and recovery of posture are regulated by other mechanisms., 資料番号: AA0063706068

Resistance to the gravitational force is a principal graviresponse in plants, comparable to gravitropism. Nevertheless, only limited information has been obtained for this graviresponse. The present study aims to clarify the mechanism of signal transformation and transduction processes, with reference to the roles of the plasma membrane and cortical microtubules. Under hypergravity conditions, the expression of genes encoding 3-Hydroxy-3-MethylGlutaryl-Coenzyme A Reductase (HMGR) was up-regulated, and the level of membrane sterols was kept higher, without influencing the level or composition of other membrane components. On the other hand, the expression of the majority of alpha- and beta-tubulin genes was up-regulated and the percentage of cells with longitudinal cortical microtubules was increased by hypergravity. Also, increases in the level and molecular size of anti-gravitational xyloglucans and 1, 3, 1, 4-beta-glucans by gravity were brought about by suppression of their breakdown with their constant or enhanced biosynthesis. We have further examined the role of membrane sterols and cortical microtubules in gravity resistance using Arabidopsis mutants. Elongation growth of both hmg and tubulin mutants was suppressed even under 1 g conditions, and hypergravity did not influence their growth, suggesting that the mutation made plants hypersensitive to the gravitational force. The analysis with mutants has also revealed that the signal transduction process via membrane sterols is distinct from that via cortical microtubules. These results indicate that membrane sterols (rafts) and cortical microtubules are deeply and independently involved in maintenance of normal growth capacity against the gravitational force., 資料番号: AA0063706113

In this research, we clarify the aerosol dynamics during thin film formation by using the Aerosol Deposition (AD) technique under the microgravity conditions. The aerosol deposition technique is useful for making thin film of ceramics materials. We are now trying this technique to make thin film of thermally unstable materials, such as clathrate compounds and/or amorphous materials. However, it is difficult to make homogeneously the aerosol of these materials in the terrestrial conditions, because in the terrestrial conditions the fine particles of these materials are settled down below the chamber during making its aerosol. Thus, in the microgravity conditions, we hope to make homogeneously aerosol for good quality of thin film by the aerosol deposition technique. For this purpose, we developed the system of AD technique under microgravity conditions during parabolic flight by airplane. Using the system, we succeeded to make thin films of (Pb (Ti, Zr) O3)(PZT(Lead Zirconate Titanate)) by the AD technique under microgravity conditions. From present results, we discussed about the relationship between aerosol flow and deposition conditions under microgravity conditions., 資料番号: AA0063349012

To investigate the effects of hypergravity on the hypothalamus of amphibians, we raised frogs, Xenopus laevis under hypergravity environment (2 and 5 G) environments from hatch to the beginning of metamorphosis (St 57) and completion of metamorphosis (St 66). The frogs developed at 2 G and 5 G, but they were smaller than those raised at 1 G. In the hypergravity-treated hypothalamus, the total volume was reduced. The length of median eminence of treated frogs was also reduced. These morphological dwarves of the hypothalamus and median eminence indicate that hypergravity alters their endocrinological functions. These results suggest that gravity different from the terrestrial environment causes dysfunction and hypofunction in the endocrine systems, and that the organisms may change their inherent life cycles under such conditions., 資料番号: AA0063349090

In osteoclast activity during space flight, inconsistent results have been reported in an in vivo study while osteoblastic function is consistently reduced by space flight. Bone matrix is an important function in the response to physical stress. However, there is no suitable in vitro co-culture system of osteoblasts and osteoclasts including bone matrix. On the other hand, fish scale is a calcified tissue that contains osteoblasts, osteoclasts, and bone matrix, all of which are similar to those found in human bones. Recently, we developed a new in vitro model system using goldfish scale. This system can be used to simultaneously detect the activities of both scale osteoclasts and osteoblasts with tartrate-resistant acid phosphatase and alkaline phosphatase as the respective markers and precisely analyze the co-relationship between osteoblasts and osteoclasts. In our co-culture system, osteoblasts and osteoclasts reacted sensitively to several degrees of acceleration, ultrasound stimulation, and micro-gravity of 3D clinostat. Therefore, we strongly believe that our in vitro co-culture system is suitable model for the analysis of bone metabolism under micro-gravity, such as that experienced in space flight., 資料番号: AA0063349091

In rodents, the immediate-early genes serve as useful neurobiological tools for mapping brain activity induced by gravity changes. In this study, we have examined brain activity related to gravity perception of medaka (Oryzias latipes) by use of c-fos expression. Fish were continuously exposed to 3 G hypergravity by centrifugation. The distribution of its transcripts within brains was analyzed by an in situ hybridization method. The 3 G-treated medakas displayed c-fos mRNA positive cells in their brain regions, which are related to vestibular function. Using the immunohistochemistry technique, the distribution and number of cells positive for c-Fos proteins were studied. The results showed that wild-type and mutant strain (ha) respond differently to 3 G exposure both quantitatively and qualitatively., 資料番号: AA0063349092

本研究では、モデル生物の1つである線虫C.elegansを用いて、微小重力や宇宙放射線をはじめとする複合的な宇宙環境ストレスが生物に及ぼす影響について調べることを目的としている。(1)我々はこれまでに、国際宇宙線虫実験ICE-first(2004年4月フライト)に参画し、宇宙で成長した線虫においても地上の対照区と同様に、減数分裂チェックポイント制御下のアポトーシスならびに卵母細胞成熟に伴う発生制御下のアポトーシスがともに正常に行われること、(2)筋肉関連の幾つかの遺伝子群ならびにタンパク質が発現レベルで顕著に低下することを見出してきた。(3)また、過重力による影響は受精直後の卵核の減数第1・第2分裂に最も影響を及ぼすことを証明してきた。(4)さらに、様々な環境ストレス(放射線など)の生物影響について、各種突然変異体やRNA干渉法(RNA interference: RNAi)による特異的な遺伝子発現の抑制体とDNAマイクロアレイを用いることにより、ゲノムワイドな分子モニターができることを明らかにしてきた。これらの結果から、複合的な宇宙環境ストレスが個体レベルに及ぼす分子影響を解析する上で、モデル生物の線虫が大変有効であることが示唆された。今後は、第1に宇宙環境におけるRNA干渉機構(RNAi)の効果を検証し、RNAiによりDNA損傷のチェックポイント制御を抑制した場合における細胞内での諸変化について調べる。さらに、アクチンや細胞骨格の再構築を介し、重力感受にも関わる可能性が想定されるRho-guanine nucleotide exchange factor(RhoGEF)の一変異体であるunc-73と野生株N2との遺伝子およびタンパク質発現の変化を比較し、シグナル伝達を含めたタンパク質のリン酸化に対する宇宙環境の影響について明らかにしたい。また、宇宙環境下で長期間、連続的な世代交代を通して生じる適応と変異・進化の方向性について明らかにすることを次なる研究課題として位置づけている。, It is important for human life in space to study the effects of environmental factors during spaceflight on a number of physiological phenomena. In the ICE-first experiment (International Caenorhabditis elegans Experiment-1, Mission DELTA, April 2004), we found that (1) both pachytene-checkpoint apoptosis and physiological apoptosis in germ cells occurred normally under spaceflight conditions and (2) certain genes related to signaling pathway of G-protein coupled receptor protein and to locomotory behavior tended to decrease in the spaceflown C. elegans. (3) In the hypergravity condition, we determined that the most susceptible aspect in the life cycle of this organism is the oocyte meiotic division for exclusion of polar bodies and the anterior-posterior polarization shortly after fertilization. (4) We also found several genes specifically responding to environmental stresses such as radiation by transcriptome analyses of entire genome using DNA microarray in several mutants and RNA interference (RNAi) animals. Since these phenomena and the identified genes are highly conserved in mammalian systems, the model experiments using this organism are useful to study the effects of space environment on human life. We are now attempting to study the RNAi effect, signal transduction, adaptation and evolution responding to space environment in future space experiments using the nematode C. elegans., 資料番号: AA0049199001, レポート番号: JAXA-RR-05-033

This study attempts to investigate abnormal Programmed Cell Death (PCD) and abnormal gene expression induced under high gravity conditions. Uncleaved Xenopus laevis eggs at 10 and 20 min after insemination, and embryos at 2 cell stage were raised at 2 G and 5 G. Controls were raised in normal gravity. PCD for body surface and inner structures of hatched tadpoles was scored using the TUNEL staining method, and gene expression was analyzed by whole-mount in situ hybridization when eggs and embryos reached tail-bud embryos. The results showed that: (1) High gravity retarded the development of eggs and embryos and induced microcephaly and microphthalmia. (2) The number of dying cells in the skin of tadpoles developed from treated eggs and cell 2 stage embryos was greater at 2 G, but less at 5 G, compared to controls. The number of PCD in head epidermis of tadpoles developed from treated eggs and embryos was higher at 2 G than in controls, but the same as controls at 5 G. Brain PCD was found to be the same at 2 G, but higher at 5 G than for controls. (3) High gravity strongly suppressed the expression of the two genes, XAG1 (regulating cement gland formation) and Xotx2 (involved in forebrain and eye development). These findings suggest that high gravity induces abnormal PCD and suppresses gene functions essential for head and brain development, leading to retardation and various morphological abnormalities., 資料番号: AA0048095063

ArabinoGalactan-Proteins (AGPs), a family of proteoglycans, are commonly found in higher plants and implicated in many physiological processes such as cell-to-cell signaling, cell adhesion, cell elongation, cell death, and stress responses. We examined the effects of hypergravity on expression of AGP species in Arabidopsis plants. Several AGP species including classical AGP, AG-peptide, and fasciclin-like AGP showed decreased expression under hypergravity conditions. Visualization of the AGP species with GFP (Green Fluorescent Protein) revealed their tissue-specific expression and confirmed the altered expression under hypergravity. The results suggest that AGPs play a role in the gravity response of higher plants., 資料番号: AA0063706110

第22回宇宙利用シンポジウム(2006年1月17日-19日, 日本学術会議6階会議室 六本木、東京), The Twenty-second Space Utilization Symposium (January 17-19, 2006: Science Council of Japan, Roppongi, Tokyo, Japan), Developing oocytes arrest at the prophase of meiosis I, while the hormone progesterone restarts the process, leading to full maturation into a fertile egg. In this study we investigated the effects of hypergravity on this phase of maturation using oocytes of Xenopus. No differences were found between 2G, 5G and untreated controls regarding time to resumption of maturation, as judged by the appearance of a white spot in the animal hemisphere, whereas the white spot itself was larger and brighter in treated oocytes at time of appearance, and became even more pronounced as maturation proceeded. These findings suggest that although hypergravity does not affect the resumption of maturation, it might adversely affect the subsequent process and final results., 共催: 日本学術会議, Meeting sponsors: The Science Council of Japan, The Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency (ISAS)(JAXA), 資料番号: AA0064113076

Plant life cycle consists of successive phases of vegetative and reproductive growth. The effects of altered gravity conditions on reproductive growth is poorly understood compared to vegetative growth, although understanding the effects is especially important not only to reveal how plants evolved under gravity on earth but to develop agriculture in space. In the present study, we examined the effects of hypergravity conditions on gene expression during reproductive growth in Arabidopsis. Microarray analysis (44 K) was performed to identify genes that are modulated in expression in response to hypergravity treatment in flower buds. Plants were grown for 20 to 26 days before exposure to hypergravity at 300 x g for 24 h. Total RNA was isolated from the flower buds (stage 1-12 according to Smyth et al. (1990)) after hypergravity treatment. Our results showed that several genes involved in reproductive growth were expressed at less than 0.2-fold levels under hypergravity condition, suggesting that expression of genes involved in flower, embryo, and seed development was suppressed under hypergravity., 資料番号: AA0063349108

We organized a working group for studying the reproduction and continuity of life under the space environment. The aim of our project is to get deep insight into the effect of space environment from various aspects, such as basic life science, applied reproductive biology, and medical sciences. This year, our group has discussed about the following research projects. First, the effects of gravity on behavior of mouse were examined. When mouse was exposed to 3G serious effects were observed in amount of food consumption, feeding period and posture resulting in loss of weight. Second, we demonstrated progesterone and melatonin both accelerated hyperactivation of sperm motility. Since hyper gravity modifies various kinds of reproduction relating hormones it could be assumed that hyper gravity might affect reproduction via modification of sperm hyperactivation. Third, apoptosis occurred during spermatogenesis especially in spermatocyte stage. Space environment might affect the function of sperm selection by modifying the apoptosis. In addition we discussed about diffusion of ATP (Adenosine Triphosphate) in sperm flagella and human sexuality. We move ahead on these projects to space experiment., 資料番号: AA0063706069

Effects of hyper-gravity (3 G) on the growth of mice were examined. The exposure of 3 G for 16 days from the weaning (23 days old) to 39 days old suppressed the growth rate of body and several organs extremely. Long exposure, either from the birth to 39 days old or from the mating to 39 days old via birth caused adaptation to the hyper-gravity, thus, suppression to the growth rate was decreased. The exposure to hyper-gravity reduced the concentration of leptin and insulin although the body weight and the amount of fat decreased. Both the leptin defect mouse (ob/ob) and leptin receptor defect mouse also lost the weight by hyper-gravity. It was assumed that the regulation of growth including the development of testis involved very complicated system., 資料番号: AA0063349069

In sea urchin embryo, the skeletogenic cells are called primary meshenchymen cells derived from micromeres at 16-cell stage. We reported a promotive effect of hypergravity in the low serum concentration culture of the skeletogenic cells. In this condition, cultured skeletogenic cells were so sensitive that they showed a clear difference of skeletogenesis also for the different substrate of culture plate. The decrease of spicule number by the inhibitor of Ca(2+)-channel is recovered under hypergravity condition. The culture in low Ca(2+) concentration also decreased the number of formed spicule and the number was recovered under hypergravity, too. These results show the possibility that the Ca(2+) uptake is one of a candidate process that is affected by hypergravity condition. The spicule also contains spicule matrix proteins. The expression of their mRNA under hypergravity was examined and the level was not different from control condition., 資料番号: AA0063349095

A working group for studying the continuity of life and reproduction under the space environment was organized. The human beings are about to move into the space environment and stay there for a long period. Reproduction becomes very important for maintain the space bases. The studies on reproduction with bird's-eye view, from the germ cell level to individual and sexual behavior have to be developed. The effects of gravity from micro-G to hyper G on reproduction are investigated and efficient study using space utilization will be proposed., 資料番号: AA0048095050

The effect of gravitational force on acquisition and retention of the Conditioned Taste Aversion (CTA) paradigm as a model of emotional learning and memory were examined. The Pseudo-Microgravity environment (PMG) was applied between 0.2 percent sodium saccharin as a Conditioned Stimulus (CS) and an intraperitoneal injection of 0.15 M LiCl as an unconditioned stimulus (US) using 3D clinostat to cancel the gravitational force. Although PMG condition did not serve as US, it suppressed both acquisition and retention of CTA Memory (CTAM). Furthermore, after CTAM acquisition with the PMG, expression of an immediately early gene, c-fos was greatly suppressed in the external lateral subnucleus of parabrachial nucleus, which strongly appeared under control condition. These results suggest that the pseudo-microgravity force impairs CTAM memory formation through suppression of neuronal activity in the gustatory pathways of brain stem., 資料番号: AA0048095052

To do Lifescience experiment inside International Space Station (ISS), it is important to keep condition of biological sample before and after microgravity experiment. In this paper the conditions of Cell culture Samples and fixatives for same duration and condition are discussed. Cell Experiment Unit (CEU) and its additional equipments are used for this experiment. It is concluded that use of the equipment is no bad effect for keeping samples inside it., 資料番号: AA0048095059

Growth of terrestrial plant is influenced by the magnitude of gravity. Hypergravity stimulus has been shown to suppress plant shoot growth by increasing the molecular mass of cell wall xyloglucans (Soga et al. 1999). And, it was found that mechanoreceptors are involved in perception of gravity stimulus in hypergravity-induced increase in the molecular mass of xyloglucans (Soga et al. 2004). These results suggest that hypergravity perceived by mechanoreceptors modifies the metabolism of cell wall xyloglucans by affecting the expression of xyloglucan endotransglucosylase/hydrolase genes. In the present study, the examinations, whether hypergravity affects the expression of XTH (Xyloglucan Translocase/Hydrolase) genes in Arabidopsis floral stem, and whether XTH genes are under the control of the mechanoreceptor, are conducted. It is demonstrated that hypergravity influenced the expression of some of XTH genes in Arabidopsis floral stems. The effect of hypergravity stimulus on the expression of these XTH genes was nullified by lanthanum chloride, which is a blocker of mechanoreceptors. These results suggest that the expression of these XTH genes in Arabidopsis is under the control of the mechanoreceptor. Further, spatial distribution patterns of these XTH mRNA in floral stem were analyzed by in situ hybridization., 資料番号: AA0048095066

第26回宇宙利用シンポジウム(2010年1月25日-26日, 宇宙航空研究開発機構宇宙科学研究本部相模原キャンパス), The Twenty-sixth Space Utilization Symposium (January 25-26, 2010: ISAS/JAXA Sagamihara, Japan), Resistance to the gravitational force is a principal graviresponse in plants,comparable to gravitropism. However, only limited information has been obtained for this graviresponse. To clarify the nature and mechanisms of gravity resistance, we have organized a research team, consisting 16 members. In the current year, we have continued discussion and exchange of information on strategy for understanding gravity resistance. We have also carried out ground-based experiments to clarify the role of cortical microtubules in gravity resistance using Arabidopsis mutants, and the effects of hypergravity on the positioning of the nucleus, osmoregulation, and stress reactions. The knowledge obtained by these activities was utilized in part to apply for the Announce of Opportunity for space experiments in Kibo during the 2nd phase., 共催: 日本学術会議, 著者人数: 16人, joint hosting: The Science Council of Japan, 資料番号: AA0064730064

We have analyzed transcriptional alterations of entire genes in spaceflown Caenorhabditis elegans on International C. elegans Experiment-1 (ICE-first) using DNA microarray. In this study, we performed gene expression analyses under certain stress conditions such as hypergravity, 3-D clinostat, gamma-ray irradiation (IR), and high Static Magnetic Field (SMF) as compared with spaceflight conditions, and constructed an integrative array database. Using the array database, we found that (1) DNA repair genes and apoptosis related genes for DNA damage response normally expressed under space environment, (2) twenty-eight genes specifically induced by IR could be identified, (3) their damage-induced genes did not increase in the ICE-first flight samples, suggesting that the samples cultured in the Soyuz Spacecraft and the International Space Station would be not severely exposed by space radiations, (4) transcriptions coding Myosin Heavy Chains (MHC) decreased in response to the space flight, and the myogenic transcription factors were also repressed, (5) from our database analysis, transcriptional alterations of an aquaporin gene aqp-4 and certain cuticle collagens in the flight samples were similar to those in the SMF administrated samples, and (6) in contrast, certain myosin genes repressed in the flight samples were temporally upregulated by the SMF administration. These observations will be a molecular basis for biological effect of space environments., 資料番号: AA0063706063

The vestibular system is known to be highly plastic. Although there were some reports about the plasticity of the vestibulo-ocular and vestibulo-spinal reflexes, it is still unclear about the plasticity of the vestibulo-cardiovascular reflex. It is possible that the plasticity of the vestibulo-cardiovascular reflex is thought to be one of the reasons in the orthostatic intolerance of the space crew. In the present study, the plasticity of the vestibulo-cardiovascular reflex was demonstrated in conscious rats reared under 3 G environment for two weeks., 資料番号: AA0063706078

It is reported that a change of gravity environment affects the growth and function of some cultured cells. But the gravity response mechanism is not well characterized. We hypothesize that a gravity change is sensed through a cytoskeleton (tensegrity model) and transduced into biochemical signals by major extracellular matrix receptor, integrin. In this paper, we examined the effect of hypergravity (60 G) on the formation of actin stress fibers in mouse osteoblast cell line MC3T3-E1. The hypergravity induced a reorganization of the stress fibers. The reorganization was reversible by a removal of the hypergravity loading. Partial destruction of stress fiber formation with cytochalasin B and GRGDS peptide was recovered by hypergravity loading. The reorganization of stress fivers by hypergravity was inhibited with a Rho kinase inhibitor, Y-27632, indicating that Rho kinase plays a critical role in the reorganization of actin stress fiber formation by hypergravity loading. This study is part of activities of the working group of Science Steering Committee for Space Utilization, JAXA-ISAS., 資料番号: AA0063706061

Sea urchin and other echinoderm animals have calcitic endoskeleton. In sea urchin embryo, skeletogenesis starts at late gastrula stage and then the spicules grow up to larval skeletons. The skeletogenic cells are called primary mesenchyme cells derived from micromeres at 16-cell stage. We already reported a promotive effect of hypergravity on skeletogenesis in the 0.25 percent horse serum culture of the skeletogenic cells. In this condition, cultured skeletogenic cells are so sensitive that they show a clear difference of skeletogenesis under the hypergravity though it is difficult to detect significant difference in the culture medium containing 4 percent horse serum. In 0.25 percent serum, the number of spicule is less than that in 4 percent serum under 1 xg condition. It recovers to the similar level significantly even in 0.25 percent under hypergravity (100 xg). In this study, we examined the effect of hypergravity on the spicule formation of the sea urchin embryo. The embryos cultured under hypergravity showed some abnormal skeletogenesis. The elongation of two arm rods (post oral rod) was suppressed in 80 percent of embryos under 100 xg condition. Under 5 xg condition most of them developed into normal larvae, but additional branching, abnormal partial thickening and excess spicule formation were observed. It is considered that spicule formation in embryo is accepting not only direct hypergravity effect but also indirect effect via surrounding tissues. The excess spicule formation observed in the embryo is correspond to the increase of spicule in the culture experiment and supposed to be one direct effect of hyper gravity., 資料番号: AA0063706057

Two Gy of heavy ion particles activated ERK1/2 at 2-5 min and 4-6 h after irradiation. Treatment of cells with 30 G for 10 sec activated ERK1/2 at 2-5 min and 4-6 h after treatment. Treatment of cells with 3D clinostat for 20 sec activated ERK1/2 at 2-5 min and 1 h after treatment. All these ERK1/2 activations were attributed to EGF receptor activation/transactivation., 資料番号: AA0063706091

The origin of Vestibular Evoked Myogenic Potentials (VEMP) is considered to include the sacculus as a sense receptor of vertical linear acceleration. In this paper, we report the influences of VEMP amplitude and latency to changes in the acceleration of gravity during a parabolic aircraft flight experiment. The parabolic flight was performed between an altitude of 7,000 and 9,500 meters and the detailed time course was as follows: (1) horizontal flight (1 G), (2) rapid ascending at 45 deg pitch up causing 2 G for 20 sec, (3) free falling causing microgravity for 20 sec, (4) descending at 35 deg pitch down causing 1.5 G. VEMP was recorded for 60 sec from the start of flight condition two to the end of flight condition four, during which the stimulating intensity was 105 dBnHL, and the stimulating frequency, 5 Hz. Seven healthy adults (six males and one female) who had no history of vertigo, deafness, or ear disease were selected as subjects, and VEMP was recorded from the left sternocleidomastoid muscles when the left ears were stimulated. The VEMP amplitude during microgravity was significantly greater than that during excessive gravity. By contrast, there were no differences among the three conditions which regard to latent VEMP. Changes in the sensitivity of the peripheral vestibular organ, i.e., sacculus, and/or the neural pathway of VEMP might increase the amplitude of VEMP during the microgravity condition. Furthermore, parabolic flight would be appropriate stimulation for evaluating saccular function on brief changes in vertical acceleration., 資料番号: AA0063349081

The major purpose of our research group is to investigate the role of gravity in the growth and development of mammalian neuromuscular system. Effects of gravitational loading at 2-G during pregnancy and/or postnatal lactation period on the properties of body composition, cardiovascular, and/or neuro-vestibular system of rats have been studied in the present study. Although the body weight was slightly light, gain of most of the organs were normal in pups grown during neonatal period at 2-G environment. Their weights relative to body weight were identical to those of 1-G group. The relative brain weight was even greater than the level of 1-G group. Physiological, biochemical and/or immunohistochemical analyses of these organs are under progress., 資料番号: AA0063349068