微重力及模拟微重力对植物生长的影响

重力对地球上生物的生长、发育、代谢及繁殖等具有重要影响.植物细胞的重力敏感性已被众多研究所证明,在空间微重力环境或地面模拟微重力环境下,植物表现特殊的微重力反应.微重力或模拟微重力会对植物体生长产生一系列的影响.综述微重力及模拟微重力对植物生长的影响,并对近期这一领域的研究进行了概括.     

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。     

空间生命科学研究的热点——植物的向重性

简要介绍了植物向重性研究的概况,以及近年来有关太空微重力环境对植物生长发育和代谢影响的研究结果,并阐述了植物向重性研究在空间生命科学中的重要意义。     

微重力条件下细胞培养和组织工程研究进展

随着空间生命科学研究的发展,人们将细胞、组织培养技术与微重力环境相结合产生了组织工程研究的一个新领域——微重力组织工程。模拟微重力条件下细胞培养和组织构建研究表明,微重力环境有利于细胞的三维生长,形成具有功能的组织样结构,培养后的三维组织无论从形态上还是基因表达上都更接近于正常的机体组织。这种微重力对细胞的作用效应,将可能为未来组织工程和再生医学研究提供一条新途径。该文概述了近十年来国内外微重力组织工程相关研究的最新进展。     

我国空间生物学效应研究的历史回顾

介绍了我国空间生物学效应的研究进展,包括植物向重性机理研究,空间环境对动物、植物和微生物的细胞结构和生长、发育、代谢等的影响,以及受控生态生命保障系统的研究。     

地球外空间环境引起植物变异的研究进展

空间诱变育种是近年来迅速发展起来的空间生命科学研究领域,由于空间环境具有超真空、微重力、宇宙射线、宇宙磁场以及超洁净的特殊条件,使植物在空间环境中发生了目前地面尚不能模拟的变化。本将近年来在返回式地面卫星、神舟飞船和俄罗斯和平号空间站搭载的种子进行的细胞学、生理学以及RAPD分子检测等方面的研究工作进行了初步总结,目前该领域中还有许多问题有待进一步深入探讨。     

从生命科学的发展谈中小学生物教学的重要性

现在生物科学也称之为生命科学,因为生物学已经从细胞水平深入到分子和量子水平。生命科学对农、林、牧、渔、医药、卫生以及生态工程都是必要的基础。这些基础应该在中小学时期打好是不言而喻的。在先进国家,已经从我们习惯认识的地球生物学发展到所谓空间生物学(Space Biology)或称作微重力生命科学(Microgravity Life Science)。在地球上我们研究的生物生长发育及其生命节奏和在太空中没有地心     

模拟微重力效应对心肌细胞一氧化氮水平的影响及其相关机制的研究

空间微重力导致的心肌收缩功能下降是航天医学的重要问题, 其发生机制尚不清楚. 采用电子自旋共振(ESR)、免疫细胞化学和核酸原位杂交等技术研究了模拟微重力效应对心肌细胞一氧化氮(NO)水平、诱导型一氧化氮合成酶(iNOS)表达的影响及其调控的信号转导途径, 以探讨模拟微重力影响心肌细胞收缩功能的可能机制. 结果表明, 模拟微重力导致心肌细胞NO水平增高, iNOS蛋白及其mRNA表达上调; 非选择性的蛋白激酶抑制剂staurosporine和选择性的蛋白激酶C ( PKC )抑制剂calphostin C均可显著抑制模拟微重力下心肌细胞NO水平增高, 说明模拟微重力对iNOS表达的调节至少是部分地依赖于PKC途径. 结果提示, 心肌细胞NO途径对模拟微重力条件敏感, 该途径可能在模拟微重力影响心肌细胞收缩功能的机制中发挥重要作用.     

植物细胞电融合技术在空间实验中的应用

细胞电融合是实用性很强的生物技术,然而在地面上由于重力沉降和热对流的影响,杂种细胞融合得率较低,使得这项技术在生产上的应用潜力难以发挥。大量的实验表明,空间微重力环境是实现细胞电融合的重要途径。今后有望利用空间微重力条件获得有价值的杂合细胞,培育作物新品种,为开展空间生物加工和空间制药提供良好基础。     

返地卫星搭载引起蛋白核小球藻性状分离

对于生物体来说,空间环境具有不同于地面的若干作用因素,如微重力,强辐射,超净等。其中,微重力因子的作用在空间生物学研究中占有突出的地位。地面上一切物体都受到重力(lg)的作用,生物体在漫长的进化过程中产生出一定的机制适应着地球的重力环境。离开地球的重力场,从低等到高等许多生物的生命过程都发现有明显     

In vitro cultured cells as probes for space radiation effects on biological systems

Near future scenarios of long-term and far-reaching manned space missions, require more extensive knowledge of all possible biological consequences of space radiation, particularly in humans, on both a long-term and a short-term basis. In vitro cultured cells have significantly contributed to the tremendous advancement of biomedical research. It is therefore to be expected that simple biological systems such as cultured cells, will contribute to space biomedical sciences. Space represents a novel environment, to which life has not been previously exposed. Both microgravity and space radiation are the two relevant components of such an environment, but biological adaptive mechanisms and efficient countermeasures can significantly minimize microgravity effects. On the other hand, it is felt that space radiation risks may be more relevant and that defensive strategies can only stem from our deeper knowledge of biological effects and of cellular repair mechanisms. Cultured cells may play a key role in such studies. Particularly, thyroid cells may be relevant because of the exquisite sensitivity of the thyroid gland to radiation. In addition, a clone of differentiated, normal thyroid follicular cells (FRTL5 cells) is available in culture, which is well characterized and particularly fit for space research.     

How and why does the proteome respond to microgravity?

For medical and biotechnological reasons, it is important to study mammalian cells, animals, bacteria and plants exposed to simulated and real microgravity. It is necessary to detect the cellular changes that cause the medical problems often observed in astronauts, cosmonauts or animals returning from prolonged space missions. In order for in vitro tissue engineering under microgravity conditions to succeed, the features of the cell that change need to be known. In this article, we summarize current knowledge about the effects of microgravity on the proteome in different cell types. Many studies suggest that the effects of microgravity on major cell functions depend on the responding cell type. Here, we discuss and speculate how and why the proteome responds to microgravity, focusing on proteomic discoveries and their future potential.     

Signal transduction in cells of the immune system in microgravity

Life on Earth developed in the presence and under the constant influence of gravity. Gravity has been present during the entire evolution, from the first organic molecule to mammals and humans. Modern research revealed clearly that gravity is important, probably indispensable for the function of living systems, from unicellular organisms to men. Thus, gravity research is no more or less a fundamental question about the conditions of life on Earth. Since the first space missions and supported thereafter by a multitude of space and ground-based experiments, it is well known that immune cell function is severely suppressed in microgravity, which renders the cells of the immune system an ideal model organism to investigate the influence of gravity on the cellular and molecular level. Here we review the current knowledge about the question, if and how cellular signal transduction depends on the existence of gravity, with special focus on cells of the immune system. Since immune cell function is fundamental to keep the organism under imnological surveillance during the defence against pathogens, to investigate the effects and possible molecular mechanisms of altered gravity is indispensable for long-term space flights to Earth Moon or Mars. Thus, understanding the impact of gravity on cellular functions on Earth will provide not only important informations about the development of life on Earth, but also for therapeutic and preventive strategies to cope successfully with medical problems during space exploration.     

Biomedical aspects of artificial gravity

Artificial gravity (AG) is the basic challenge for space biology and medicine. The importance of this problem is associated with the fact that duration of the space missions will become progressively longer, but the presently available countermeasures do not provide reason enough to predict the human health safety during space missions of any duration. The creation of AG could be an efficient method for removing the negative effects of microgravity. Two principle methods of generating AG, rotation of space system (SS) and building of short arm centrifuge (SAC), have been proposed. The purpose of the present work is to review the biomedical aspects of AG in the context of its use in long-term space missions.     

Gravitational biology and space life sciences: Current status and implications for the Indian space programme

This paper is an introduction to gravitational and space life sciences and a summary of key achievements in the field. Current global research is focused on understanding the effects of gravity/microgravity on microbes, cells, plants, animals and humans. It is now established that many plants and animals can progress through several generations in microgravity. Astrobiology is emerging as an exciting field promoting research in biospherics and fabrication of controlled environmental life support systems. India is one of the 14-nation International Space Exploration Coordination Group (2007) that hopes that someday humans may live and work on other planets within the Solar System. The vision statement of the Indian Space Research Organization (ISRO) includes planetary exploration and human spaceflight. While a leader in several fields of space science, India is yet to initiate serious research in gravitational and life sciences. Suggestions are made here for establishing a full-fledged Indian space life sciences programme.     

Microgravity effects on thylakoid,single leaf,and whole canopy photosynthesis of dwarf wheat

The concept of using higher plants to maintain a sustainable life support system for humans during long-duration space missions is dependent upon photosynthesis. The effects of extended exposure to microgravity on the development and functioning of photosynthesis at the leaf and stand levels were examined onboard the International Space Station (ISS). The PESTO (Photosynthesis Experiment Systems Testing and Operations) experiment was the first long-term replicated test to obtain direct measurements of canopy photosynthesis from space under well-controlled conditions. The PESTO experiment consisted of a series of 21–24 day growth cycles of Triticum aestivum L. cv. USU Apogee onboard ISS. Single leaf measurements showed no differences in photosynthetic activity at the moderate (up to 600 μmol m⁻² s⁻¹) light levels, but reductions in whole chain electron transport, PSII, and PSI activities were measured under saturating light (>2,000 μmol m⁻² s⁻¹) and CO₂ (4000 μmol mol⁻¹) conditions in the microgravity-grown plants. Canopy level photosynthetic rates of plants developing in microgravity at ∼280 μmol m⁻² s⁻¹ were not different from ground controls. The wheat canopy had apparently adapted to the microgravity environment since the CO₂ compensation (121 vs. 118 μmol mol⁻¹) and PPF compensation (85 vs. 81 μmol m⁻² s⁻¹) of the flight and ground treatments were similar. The reduction in whole chain electron transport (13%), PSII (13%), and PSI (16%) activities observed under saturating light conditions suggests that microgravity-induced responses at the canopy level may occur at higher PPF intensity.     

Gravity independence of seed-to-seed cycling in Brassica rapa

 Growth of higher plants in the microgravity environment of orbital platforms has been problematic. Plants typically developed more slowly in space and often failed at the reproductive phase. Short-duration experiments on the Space Shuttle showed that early stages in the reproductive process could occur normally in microgravity, so we sought a long-duration opportunity to test gravity's role throughout the complete life cycle. During a 122-d opportunity on the Mir space station, full life cycles were completed in microgravity with Brassica rapa L. in a series of three experiments in the Svet greenhouse. Plant material was preserved in space by chemical fixation, freezing, and drying, and then compared to material preserved in the same way during a high-fidelity ground control. At sampling times 13 d after planting, plants on Mir were the same size and had the same number of flower buds as ground control plants. Following hand-pollination of the flowers by the astronaut, siliques formed. In microgravity, siliques ripened basipetally and contained smaller seeds with less than 20% of the cotyledon cells found in the seeds harvested from the ground control. Cytochemical localization of storage reserves in the mature embryos showed that starch was retained in the spaceflight material, whereas protein and lipid were the primary storage reserves in the ground control seeds. While these successful seed-to-seed cycles show that gravity is not absolutely required for any step in the plant life cycle, seed quality in Brassica is compromised by development in microgravity. Received: 3 August 1999 / Accepted: 27 August 1999     

Physiology in microgravity.

Studies of physiology in microgravity are remarkably recent, with almost all the data being obtained in the past 40 years. The first human spaceflight did not take place until 1961. Physiological measurements in connection with the early flights were crude, but, in the past 10 years, an enormous amount of new information has been obtained from experiments on Spacelab. The United States and Soviet/Russian programs have pursued different routes. The US has mainly concentrated on relatively short flights but with highly sophisticated equipment such as is available in Spacelab. In contrast, the Soviet/Russian program concentrated on first the Salyut and then the Mir space stations. These had the advantage of providing information about long-term exposure to microgravity, but the degree of sophistication of the measurements in space was less. It is hoped that the International Space Station will combine the best of both approaches. The most important physiological changes caused by microgravity include bone demineralization, skeletal muscle atrophy, vestibular problems causing space motion sickness, cardiovascular problems resulting in postflight orthostatic intolerance, and reductions in plasma volume and red cell mass. Pulmonary function is greatly altered but apparently not seriously impaired. Space exploration is a new frontier with long-term missions to the moon and Mars not far away. Understanding the physiological changes caused by long-duration microgravity remains a daunting challenge.     

Gut microbiome and human health under the space environment

The gut microbiome is well recognized to have a pivotal role in regulation of the health and behaviour of the host, affecting digestion, metabolism, immunity, and has been linked to changes in bones, muscles and the brain, to name a few. However, the impact of microgravity environment on gut bacteria is not well understood. In space environments, astronauts face several health issues including stress, high iron diet, radiation and being in a closed system during extended space missions. Herein, we discuss the role of gut bacteria in the space environment, in relation to factors such as microgravity, radiation and diet. Gut bacteria may exact their effects by synthesis of molecules, their absorption, and through physiological effects on the host. Moreover we deliberate the role of these challenges in the dysbiosis of the human microbiota and possible dysregulation of the immune system.