DLR - Clinostats, Centrifugues, RPM.

CLINOSTATS

2D Clinostats (clinostats with one rotation axis) enable the rotation of a sample perpendicular to the gravitational field. By this approach gravity is not eliminated; however, as the biological system is continuously reoriented, it is assumed that it does no longer perceive the 1 g stimulus. We use 2D fast-rotating clinostats in which the samples are rotated with a rotation speed of 50 – 100 rpm (rounds per minute). Depending on the experimental demands different kinds of clinostat devices have been developed:

Clinostat Microscope

Clinostat Microscope

A clinostat microscope enables the online observation in functional weightlessness. The basis is a horizontally positioned microscope. Further characteristics are objectives up to 63 fold, a digital camera, video registration, a fluorescence unit and an external controllable stage. The rotation speed can be selected from 2-90 rpm.

Specifications:

Microscope: Zeiss Axiovert

Remote controlled cross table
Objectives: up to 63 fold
Online observing with digital image processing
Fluorescence unit

Clinostat:

Rotation speed: 2 –100 rpm
Temperature: 20 – 37°C

Camera:
Resolution: 640 x 480 px
Video Pal –B signal

Clinostat for Pipettes

With this clinostat device fixation of samples during rotation is now possible. Thus effects by stopping the clinostat and thus termination of the experiment under 1 g conditions can be avoided. Up to 10 samples (within 1 ml pipettes) can be processed in parallel. Under the chosen experimental conditions (60 rpm, pipette diameter (4 mm)) a maximal residual acceleration of 4×10 -3 g is achieved at the border of the pipette, which decreases towards the center. Depending on the experimental demands a defined temperature and atmosphere can be applied during clinorotation.

Specifications:

Up to 10 pipettes per run
Rotation speed: 60 – 90 rpm
Temperature controlled
Atmosphere defined
Fixation of all samples during clinorotation

Submersed Clinostat

For studies of aquatic systems a clinostat with the possibility to submerse the experimental set-up in an aquarium has been constructed. It has been successfully used for developmental studies on fish.

Specifications:

6 clinostat tubes with space for e.g. 6 to10 fish larvae
Rotation speed: 20 – 90 rpm
Temperature: 18-36°C
Defined environment
Fresh water supply for each tube

Rotating wall vessel

Additional and for comparative studies a rotating wall vessel (according to the NASA design) was adapted in the submersed clinostat assembly. Fish can be processed in the rotating wall vessel simultaneously to the submersed clinostat and the non – rotating 1 g control.

Specifications:

Rotation speed: 20-90 rpm
Fresh water supply

Photomultplier Clinostat

The photomultiplier clinostat was developed to investigate on-line kinetics of bioluminescent signals during clinorotation. Cell cultures samples can be processed in a light-tight box. The measurement are performed with an electronic photomultiplier linked to a counter-system. Obtained data are recorded on a PC system over a serial connection. The whole system can be inserted into an incubator for defined environmental conditions.

Specifications:

Online measurement of bioluminescence signals and cell activity
Rotation speed: 10 – 90 rpm
Defined environment

Horizontal Laser Scanning Microscope

One way to study the impact of gravity on biological systems is to observe their behavior in a horizontally positioned observation unit. Such an experimental setup can be applied to observe online, how gravity influences, e.g., plant growth and the behavior of free-moving organisms. In collaboration with Nikon (Nikon, Düsseldorf, Germany) a confocal microscope (Nikon Eclipse 80i) was placed horizontally, equipped with a 360° turnable microscope stage, objectives up to 100 fold and a scanning resolution up to 2048×2048. 3D observations with time laps function (4D) are implemented. After specific labelling of the sample the in vivo analysis of cellular components during gravitropic or gravitactic responses can now be studied.

Specifications:

Microscope:

NIKON Eclipse 80i Laser Scanning Microscope
Three laser wave length: 405, 488 and 543 nm
360° pivotable object table
Objective: up to 100 fold (violet corrected)
Filter systems: V-2A, FITC and TRITC

CENTRIFUGES

As responses to gravity are normally rather weak, they can be increased under elevated accelerations created by centrifuges. Furthermore, knowledge of the effects of hypergravity conditions during launch and parabolic flights is essential for the interpretation of the results obtained from microgravity experiments.

NIZEMI

The equipment consists of the Slow Rotating Centrifuge Microscope (Niedergeschwindigkeits-Zentrifugen-Mikroskop NIZEMI) for hyper- g experimentation in the range of 1 to 6 g . Microscopical and/or macroscopical parts allow observation of small organisms or systems up to a maximum sample size of approx. 40 mm. On-line observations during centrifugation is provided. The slow rotating centrifuge NIZEMI has been successfully used for threshold studies on various systems during the Spacelab mission IML 2. The ground model is used for hypergravity experiments up to 6 g . The system consists of a microscope and a macro-observation unit, both mounted tangentially on a rotating platform.

Specifications:

Microscope: Zeiss Axiovert

Remote controlled cross table and objective revolver
Objectives: up to 40 fold
Online observing with digital image processing

Centrifuge:

Acceleration up to 6 g

MuSIC – Multi-Sample Incubation Centrifuge

The Multi-sample Incubation Centrifuge (MuSIC) provides up to four sample platforms (diameter 42 cm) and is especially designed for low rotation forces (i.e. up to 20 g ), though higher g forces are possible. A various number of samples, up to several hundreds of samples in the ml range, can be processed in parallel. This centrifuge provides variable inner accommodation for small plant or animal organisms, aquatic vertebrates or invertebrates or physico-chemical systems. A life support system consisting of water purification, aeration, feeding etc. is available. The temperature is controlled; light-dark cycles can be applied.

Specifications:

Acceleration 1 to 20 g
Defined environment with light-dark cycles
Temperature: 4 – 40°C
Up to 200 samples

Desktop RPM

The Desktop RPM (Dutch Space) is a small size ‘Random Positioning Machine' that randomly rotates the accommodated experiment package around the Earth's gravity vector.

Two operational modes are available: real time generation of a random profile with user defined control parameters or execution of a previously calculated random path using a constant rotation rate. The path parameters can be selected from a user interface provided by a PC.

Specifications:

Experiment volume 15 cm 3 (max)
Experiment mass up to 1.5 kg
12 slip-ring tracks (e.g. for power, communication, video)
Controlled environment (within an incubator)

REFERENCES

Hemmersbach, R., von der Wiesche M. and Seibt, D (2006).: Ground-based experimental platforms in gravitational biology and human physiology. Signal Transduction 6, 381-387, 2006.

Häder, D.-P., Hemmersbach, R. a nd Lebert, M. (2005): Gravity and the Behaviour of Unicellular Organisms. Developmental and Cell Biology Series, 40 . Cambridge University Press , 258 S. ISBN 13 978-0-521-82525-9. ISSN 10 0-521-82523-4

Gerzer, R., Hemmersbach, R., Horneck, G. (2006): Life Sciences. In: Utilization of Space. Today and Tomorrow Springer, Berlin , Heidelberg , New York , Seiten 341-373. ISBN 3-540-25200-2; 978-3-540-25200-9.

CONTACT

Facillities:

PD Dr. Ruth Hemmersbach
Institute for Aerospace Medicine
Biomedical Science Support Center
Linder Höhe
51147 Köln

Phone: +49 2203 601 3094
Fax: +49 2203 696212
E-Mail: Ruth.Hemmersbach@dlr.de

Technical Questions:

Dr. Jens Hauslage
Institute for Aerospace Medicine
Biomedical Science Support Center
Linder Höhe
51147 Köln

Phone: +49 2203 601 4537
Fax: +49 2203 696212
E-Mail: Jens.Hauslage@dlr.de

Last update: 23 January 2012

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