模拟微重力条件对植物幼苗生长的影响

与正常重力下生长的植物幼苗对照相比,在竖直平面内径回转器连续做１２０ｈ圆周回转的草莓和香石竹幼苗的生长状况发生如下变化：（１）株高和叶片数有所增加;（２）草莓的叶绿素含量降低４７．５％,香石竹叶绿素含量增加４．３％;（３）回转后两种幼苗的叶绿素的主要吸收峰位不变,而每个峰位吸收强度有所增加;（４）两思苗的叶片快速荧光动力学参数,回转后除ＣＡ／Ｆ０外,Ｆｖ／Ｆｏ、Ｆｖ／Ｆｍ和Ｔ１／２均有提高;（５）     

模拟微重力条件对植物幼苗生长的影响

与正常重力下生长的植物幼苗对照相比 ,在竖直平面内经回转器连续做 12 0h圆周回转的草莓和香石竹幼苗的生长状况发生如下变化 :(1)株高和叶片数有所增加 ;(2 )草莓的叶绿素含量降低 47.5 % ,香石竹叶绿素含量增加 4.3% ;(3)回转后两种幼苗的叶绿素的主要吸收峰位不变 ,而每个峰位吸收强度有所增加 ;(4 )两种幼苗的叶片快速荧光动力学参数 ,回转后除CA/F0 外 ,Fv/F0 、Fv/Fm 和T1/ 2 均有提高 ;(5 )对照和处理的叶绿体的两个光系统间的激发能分配有差异 ,但未影响处理的叶绿体的光合功能     

生长素和模拟微重力效应对大白菜不定根形态发生的影响

Under the induction of indole-3-acetic acid (IAA), adventitious roots were differentiated on hypocotyl segments derived from seedlings of Chinese cabbage (Brassica campestris spp. pekinensis). IAA at concentration of 0.4-1.0 mg/L in solid MS medium incited many adventitious roots on hypocotyl segments. The earliest anatomic changes were observed on cut surface of hypocotyl segments under optical microscope 24 hours after IAA treatment: cytoplasmic and nuclear density became higher in a few of parenchytmatous cells adjacent to phloem in tissue of pericycle, followed by cell divisions. Lately, the dividing cells expanded and developed into root primordium from which root cap was differentiated. After five days, most roots protruded through hypocotyl cortex and appeared just below the cut surface. The rooting capacity of the segments derived from three regions of each hypocotyl was different. High level of IAA modified the polarity of root formation on segment inserted upside down and sucrose increased the function of IAA. Additionally, microgravity did not significantly change the rooting polarity under the condition of stimulated microgravity, but it increased the competence of explants to IAA treatment. The results presented here provided an experimental system for further investigation of molecular events associated with adventitious root initiation.     

模拟微重力对拟南芥幼苗的影响

对正常条件和模拟微重力条件下拟南芥幼苗的生长状况进行了研究,发现拟南芥幼苗的生长发育、生理生化特性、酶活性等均发生一系列的变化.并利用qRT-PCR技术深入研究了经模拟微重力处理的幼苗过氧化物酶的基因表达量的变化.这些结果为植物在受控生态生保系统中的生长提供了试验支持.     

微重力植物细胞生理学研究进展

本文介绍1985年以来微重力植物细胞生理学飞行试验和地面模拟研究进展。     

模拟微重力效应对果蝇运动及睡眠的影响

本研究旨在探讨利用模拟微重力效应研究微重力对果蝇运动及睡眠影响的可行性.通过研制能够在模拟微重力环境下实时监测果蝇行为的随机定位仪,监测短时间(3 d)模拟微重力处理过程中,及长时间(10 d、20 d、30 d)处理后雄蝇运动和睡眠的变化;选取受影响较显著的短时间处理组,研究模拟微重力效应对生物钟核心基因(period (per)、timeless(tim)、clock (clk)、cycle (cyc)、cryptochrome (cry))、神经递质多巴胺(dopamine,DA)和5-羟色胺(5-hydroxytryptamine,5-HT)关键合成酶(多巴脱羧酶、酪氨酸羟化酶、色氨酸羟化酶)的编码基因ddc、pale和trh表达水平及DA和5-HT含量的影响.结果显示:短时间暴露下,雄蝇夜晚的运动量增加、单位时间运动次数增加、睡眠时间和次数减少、生物钟基因tim、clk、cyc、cry及神经递质合成相关编码基因ddc、pale和trh的表达水平均显著上升;长时间处理后对雄蝇运动和睡眠的影响较小.本研究认为利用模拟微重力效应研究微重力对果蝇运动及睡眠的影响是可行的,相关研究结果对航天医学研究具有借鉴意义.     

模拟微重力对拟南芥幼苗的生物学效应

对正常条件和模拟微重力条件下生长的拟南芥幼苗进行比较试验,结果表明模拟微重力会产生如下影响:(1)影响拟南芥幼苗的生长发育;(2)影响拟南芥光合特性;(3)影响拟南芥的生理特性;(4)影响拟南芥植株的钙离子分布。此外,运用基因芯片技术探讨模拟微重力对拟南芥基因表达的影响。     

模拟微重力对肺动脉和胸主动脉的影响

目的 :通过对模拟微重力 (SM)、肺动脉 (PA)和胸主动脉 (TA)局部调节机理研究 ,为大小循环动脉对SM适应机理和SM后立位耐力降低机理研究积累资料。方法 :XXH 2 0 0 0型小循环心功能检测仪检测人体头低位 6°卧床(HDT) 7d心肺循环功能变化。 - 30°尾部悬吊 (TS)大鼠模拟微重力 (microgravity ,M)的生理效应 ,测量 7d、1 4dPA和TA的反应性。结果 :人体HDT初期每搏PA(hz)、静脉 (hc)容量和左心前负荷 (hc/hz)均显著增加 ,96～ 1 4 4h大小循环均出现超调现象 ,前者出现时间早、幅度大。 7d尾部悬吊大鼠 (TS7)与对照组 (CON)比PA舒张反应显著增强 ,TS1 4有降低趋势。TS7TA与CON比舒张反应显著增强 ,TS1 4轻度升高。TS7PA收缩反应与CON比轻度降低 ,TS1 4显著降低。TS1 4TA收缩反应显著降低。去VECPA对KCl、苯肾上腺素和硝普钠的反应在所有组间无差异。结论 :SM对大小循环动脉影响不同 ,可能是SM时局部调节功能降低的重要表现 ,主要由于动脉血管内皮细胞功能变化 ,对立位耐力降低可能有贡献     

模拟微重力生物效应回转器的研制与应用

研制出一种在地面从事微重力生物学、医学实验模拟用的新型回转器。它可用来模拟空间微重力的生物效应,进行植物种苗、微生物、小动物和各种细胞培养的实验。文中对该仪器的工作原理、构造及研制应用情况分别作了具体说明。     

在地面进行微重力生物学实验模拟用的回转器

生物的生长、发育都处于重力作用之下。解除重力的作用,以研究重力对生物的效应,有助于阐明生命科学中的许多基本问题。到了空间时代,人们才可能使生物较长时间处于微重力条件之下进行此类研究。     

失重/模拟失重对内皮细胞的影响实验研究进展

血管内皮作为血管壁的衬里,参与调节组织器官的局部血流和机体其它生理进程,在维持血管完整性和内环境稳定中发挥关键作用。内皮细胞对包括重力在内的机械应力刺激极为敏感,重力变化可对其形态和功能构成不同程度的影响。研究发现,失重/模拟失重通过诱导内皮细胞细胞骨架重塑、质膜caveolae重布,使其合成分泌血管活性物质、炎性介质的能力以及细胞表面粘附分子表达发生改变,这些分子变化又对内皮细胞的生长、增殖、凋亡、迁移和血管生成等具有精细调控作用。本文综合评述了失重/模拟失重对内皮细胞功能的影响,同时围绕文献报道中一些尚存争议的观点进行了适当讨论。     

Growth and Development in Arabidopsis thaliana through an Entire Life Cycle under Simulated Microgravity Conditions on a Clinostat

Arabidopsis thaliana ecotype Columbia and Landsberg erecta were studied. Horizontal clinorotation affected little germination of seeds, growth and development of rosette leaves and roots during early vegetative growth stage, and the onset of the bolting of inflorescence axis and flower formation in reproductive growth stage, although it suppressed elongation of inflorescence axes. The clinorotation substantially reduced the numbers of siliques and seeds in Landsberg erecta, and completely inhibited seed production in Columbia. Seeds produced in Landsberg erecta on the clinostat were capable of germinating and developing rosette leaves normally on the ground. On the other hand, growth of pin-formed mutant (pin/pin) of Arabidopsis ecotype Enkheim, which has a unique structure of inflorescence axis with no flower and extremely low levels of auxin polar transport activity, was inhibited and the seedlings frequently died during vegetative stage on the clinostat. Seed formation and inflorescence growth of the seedlings with normal shape (pin/+ or +/+) were also suppressed on the clinostat. These results suggest that the growth and development of Arabidopsis, especially in reproductive growth stage, is suppressed under simulated microgravity conditions on a clinostat. To complete the life cycle probably seems to be quite difficult, although it is possible in some ecotypes. Received 18 June 1999/ Accepted in revised form 27 August 1999     

Adaptation of Mature Spathiphyllum sp. Plant to Prolonged Simulated Microgravity

Mature Spathiphyllum sp. plants were grown in soil in pots under clinostatic or stationary condition. Photosynthetic rate fell to almost zero after 30 d in clinostat, but recovered to more than 60% of the original on the 62nd day. Grana in chloroplasts remained normal in clinostat. There were few starch grains in chloroplasts after 30 d in clinostat, and almost none on the 62nd day, but numerous globular objects of low electronic density were observed. These were probably related to the adaptative changes of photosynthesis. Cell division in meristematic cells of root cap ceased after 30 d in clinostat, and then resumed to attain a rate even higher than that in the control plant on 62nd day, Further the length of the tap root was more than double that in the control plants. Some of the meristematic cells in the root cap under clinstatic condition transformed into statocyst cells, which senesced and were not transformed into secretory cells. No exocytosis was observed in plant in clinostatic condition, albeit the cell wall was broken from abrasion during root growth, resulting in pseudo-exocytosis, and from which the exudates acted as lubricants for the free extension of the root tip during root growth.     

间断性人工重力对模拟失重大鼠颈总动脉平滑肌细胞凋亡的影响

目的:研究3周模拟失重大鼠颈总动脉平滑肌细胞凋亡的变化及间断性人工重力对其的影响。方法:以尾部悬吊大鼠(SUS)模拟失重,同期每天悬吊23h、站立1h(STD)模拟间断性人工重力的对抗效果,用M30染色及Tunel染色方法观察3周SUS组、同步对照(CON)组及STD组颈总动脉平滑肌细胞早期和中晚期的凋亡情况,并用免疫组织化学方法及Western blot印迹方法观察各组大鼠颈总动脉组织Caspase-3的蛋白表达变化。结果:与CON组比较,SUS组大鼠颈总动脉平滑肌细胞M30染色阳性细胞明显减少,STD组M30染色阳性细胞较CON组及SUS组显著增加;SUS组Tunel染色阳性细胞较CON组及STD组显著减少,STD组Tunel染色阳性细胞较CON组及SUS组显著增加;SUS组Caspase-3的表达较CON组显著降低(P<0.05),STD组Caspase-3的表达较CON组及SUS组显著增高(P<0.01)。结论:模拟失重可引起大鼠颈总动脉平滑肌细胞凋亡减少,每日1 h的-Gx对抗使颈总动脉的凋亡增加。Caspase-3可能在调控模拟失重所致血管组织平滑肌细胞的凋亡中发挥作用。     

模拟微重力通过调节AKT磷酸化抑制前成骨细胞的增殖

目的:研究模拟微重力对前成骨细胞的增殖作用及其分子机制。方法:利用2D回转器模拟失重条件培养前成骨细胞MC3T3-E1 24小时;将p-AKT激活剂SC79加入细胞培养基后模拟失重条件下培养前成骨细胞MC3T3-E1 24小时;利用Western blot技术分别检测细胞增殖相关蛋白PCNA以及AKT、p-AKT的表达变化情况。结果:(1)与对照组相比,模拟失重组前成骨细胞增殖受到抑制(P0.01),p-AKT/AKT比值减小(P0.01);(2)加入SC79组与对照组相比,p-AKT/AKT比值显著增加;(3)加入SC79的模拟失重组(MG+SC79)与模拟失重组相比(MG),p-AKT/AKT比值增加,PCNA蛋白表达增加(P0.01),成骨细胞增殖有所恢复。结论:模拟微重力可能通过抑制AKT的磷酸化形式抑制前成骨细胞的增殖,加入p-AKT激活剂可部分恢复前成骨细胞的增殖。     

Proteomic Analysis of Mouse Hypothalamus under Simulated Microgravity

Exposure to altered microgravity during space travel induces changes in the brain and these are reflected in many of the physical behavior seen in the astronauts. The vulnerability of the brain to microgravity stress has been reviewed and reported. Identifying microgravity-induced changes in the brain proteome may aid in understanding the impact of the microgravity environment on brain function. In our previous study we have reported changes in specific proteins under simulated microgravity in the hippocampus using proteomics approach. In the present study the profiling of the hypothalamus region in the brain was studied as a step towards exploring the effect of microgravity in this region of the brain. Hypothalamus is the critical region in the brain that strictly controls the pituitary gland that in turn is responsible for the secretion of important hormones. Here we report a 2-dimensional gel electrophoretic analysis of the mouse hypothalamus in response to simulated microgravity. Lowered glutathione and differences in abundance expression of seven proteins were detected in the hypothalamus of mice exposed to microgravity. These changes included decreased superoxide dismutase-2 (SOD-2) and increased malate dehydrogenase and peroxiredoxin-6, reflecting reduction of the antioxidant system in the hypothalamus. Taken together the results reported here indicate that oxidative imbalance occurred in the hypothalamus in response to simulated microgravity.     

模拟微重力条件下几种植物的过氧化物酶同工酶谱分析

对模拟微重力条件下的人参果、马铃薯和草莓处理后进行了过氧化物酶同工酶谱分析实验。结果表明 ,在模拟微重力条件下过氧化物同工酶的活性明显增强