Đang chuẩn bị liên kết để tải về tài liệu:
Innovations in Biotechnology Part 12

Tham khảo tài liệu 'innovations in biotechnology part 12', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | Gene Expression Microarrays in Microgravity Research Toward the Identification of Major Space Genes 321 al 1998 Pardo et al 2005 denervation Nikawa et al 2004 and diamagnetic levitation Dai et al 2009 Hammer et al 2009 . Bed rest with the head tilted down at 6 has been found to induce physiological alterations similar to those experienced in the space environment. In a similar way tail suspension for mice and rats presents physiological effects analogous to those observed in a microgravity environment. To date most of the microarray based studies of microgravity effects on gene expressions have used the ground-based RWV and RPM bioreactors to simulate microgravity environment Figure 1 Table 1 . The following section in the introduction gives a brief overview of the major kinds of simulated microgravity models. Fig. 1. The pie chart shows the percentage of each kind of microgravity used for the microarray studies discussed in this chapter. 1.1.1 Some ground-based simulated microgravity in bioscience research Ground-based gravity-simulation experiments at the cellular and molecular levels have gained much insight into the underlying molecular and cellular alterations induced by microgravity stress as well as the mechanisms of the microgravity effects. In ground-based microgravity bioscience research most simulation models simulate reduced gravity in the range of 10-4 10-6 g which is very small close to micro 10-6 g level Klaus 2001 . The most commonly used devices for simulating a microgravity environment are the RWV Figure 2A and the RPM Figure 2B which are also known as the 3D clinostat van Loon 2007 . The RWV and RPM bioreactors were developed to simulate microgravity by mimicking a functional weightless state. The RWV bioreactor rotates cells in a zero head space suspension culture that keeps the cells in a near free fall state Figure 2A which we have used for our studies Clement et al 2007 2008 . The RPM is constructed of two independently rotating frames one .