Abstracts 3rd NL-Gravity & Astrobiology Symposium 15/16 May 2001.
Free University Amsterdam. The meeting is in a different room each day. Tuesday 15 in lecture room D-113 in the 'Provisorium'. A two story building at de Boelelaan 1115. Wednesday 16 in lecture room 8A05 in the main building at de Boelelaan 1105. Click here for travel direction to the Free University.
GRAVITY SIGNAL TRANSDUCTION IN CILIATES
- EXPERIMENTAL STRATEGIES
Richard Bräucker1 and Ruth Hemmersbach2
1Rheinische
Friedrich-Wilhelms University, Institute of Zoology, D-53115 Bonn, Germany 2Institute
of Aerospace Medicine, DLR, D-51147 Cologne, Germany E-mail: richard.braeucker@gmx.de;
Phone: +49 2203 601 3094; Fax: +49 2203 601 4598
Ciliates are free swimming unicellular organisms, which arose
on the earth more than 1.5 billion years ago. As for free swimming organisms,
the capability of orientation is a great benefit in evolution, ciliates react
to a wide variety of stimuli. Among the physical and chemical parameters of
an aquatic environment, the gravity vector is unique, because it is constant
in its value and direction; thus being the most reliable cue for orientation.
We have evidence, that ciliates, like Paramecium, sense the gravity stimulus
and react with a change in swimming velocity and swimming direction. In order
to identify the signal transduction chain of graviperception in ciliates, several
strategies are possible:
1. Stimulus level
Although the gravity vector is indispensable for studies on graviperception,
it is necessary to do control experiments under conditions of weightlessness
(drop facilities, sounding rockets, parabolic flights, spaceflights). Many fruitful
results have been derived using increased acceleration as in centrifuges. Up
to 6g, the graviresponses in most ciliates are functions of acceleration; i.e.
the graviresponses are increased.
2. Receptors
Due to our hypothesis, gravireceptors are (specialised) mechanoreceptors.
By determination of response times and thresholds they can be closer characterised.
From step experiments to µ-g conditions, we assume the involvement of assisting
structures, such as the cytoskeleton, in graviperception. Comparing known species-specific
differences in the distribution of mechanoreceptors (e.g. Paramecium
versus Didinium) we proved our hypothesis of graviperception. Modification
of the cell shape and, if possible, the use of specific channel blockers, may
elucidate more of the nature of gravisensors.
3. Membrane potential
It is well known that the behaviour of ciliates is under the strict control
of membrane potential. All sensory processes are summarised in potential changes.
Hence, we are trying to directly measure a gravireceptor potential by means
of intercellular electrophysiological recording.
4. Second messenger
The role of second messengers (such as cAMP and cGMP, calmodulin) has been
demonstrated in ciliary activity and thus swimming behaviour. Currently it is
investigated, whether second messengers are involved in the gravitransduction
chain.
5. Analysis of behaviour
Most evidences in graviresponses have been given from the analysis of behaviour.
While inspection of swimming direction displays gravitaxis, the analysis of
gravity dependent swimming velocities reveals gravikinesis. The comparison of
different locomotion types (such as swimming, gliding and walking on substrates)
may increase our knowledge of gravireceptors. An evolutional question is, whether
the distribution and function of mechanoreceptors in ciliates depends on the
presence of gravity, which may be examined under the conditions of long-term
weightlessness, e.g. on the International Space Station.
MICROBIAL GROWTH KINETICS UNDER CONDITIONS OF MICROGRAVITY
Janneke Krooneman, Hilma Hammenga. Marjan van der Velde, Jaap van
der Waarde
Bioclear Environmental Biotechnology, PO Box 2262, 9704 CG Groningen, The
Netherlands. E-mail: Krooneman@bioclear.nl;
Phone:+31(0)505718455 ; Fax : +31(0)50-5717920
Within the framework of research on life support systems, experiments
were set up to determine the characteristics of bacterial growth kinetics under
microgravity conditions. The research project is supported by both the ESA and
the Netherlands Agency for Aerospace Programs (NIVR). Aim of the project is
the development of a system for the removal and complete oxidation of gaseous
and airborne contaminants originating in confined atmospheres with the use of
micro-organisms in order to purify and recycle air in manned space aircraft.
Water and air are essential raw materials for manned space missions. Recycling
of these materials is one of the biggest challenges in the further space exploration.
The application of biotechnological techniques with as ultimate goal a fully
closed ecological life support system is seen as the only solution.
The principle of the Biological Air Filter (BAF-system) is based on a support/sorbant
membrane material colonised by selected micro-organisms in a near resting state,
oxidising the various contaminants. Two experimental BAF modules have already
been designed, constructed and successfully tested. Laboratory experiments with
the experimental models showed a high efficiency for the removal of the selected
contaminants and demonstrated a good potential for space application.
Main objective of the presented work is the determination of the influence of
the space environment on the growth-kinetics of the biodegradation of the air-contaminant
1,2-dichloroethane by micro-organisms at the degradation of organic volatile
contaminants. The overall growth rate that the bacterial cells can reach depend
on 1) the prevalent substrate concentration(s), 2) a cascade of biochemical
reactions involved in the metabolism of the substrate, including the uptake
and transport of the substrates, and 3) the kinetic properties of the enzymes
involved in these reactions, and 4) the prevalent environmental conditions,
such as temperature, pH and for instance the absence or presence of gravity.
In space where sedimentation of the bacterial cells is absent, it is thought
that concentrations of physiologically important cellular metabolites will leak
out of the bacterial cells. In the absence of gravity the cells will remain
in close proximity to these excreted or diffused metabolites, leading to little
energetic loss. In the presence of gravity (1 g) the cells will sediment away
from these metabolites leading to energy loss. Therefore it is hypothesized
that bacterial cells modify their micro-environment in such a way resulting
in (i) increased maximum specific growth rates/ substrate degradation rates
in space as compared to growth on Earth, (ii) increased substrate affinities
in space as compared to growth on Earth, (iii) increased molar cell yields in
space as compared to growth on Earth and (iv) higher concentrations of excreted
(by)products or metabolites on Earth as compared to growth in space.
In the current presentation results will be shown of base-line data collection
to demonstrate the bacterial growth kinetics for the degradation of 1,2-dichloroethane
under conditions of gravity (1 g). In addition, the experimental set-up will
be shown for the study of the bacterial growth kinetics for 1,2-dichloroethane
that will be performed under microgravity conditions at the space-shuttle flight
STS-107.
Click here
for actual presentation.
MICROGRAVITY AND BONE CELL MECHANOSENSITIVITY: RHEOLOGICAL CHARACTERIZATION
OF THE PARALLEL-PLATE FLOW CHAMBER.
R.G. Bacabac1, Th.H. Smit2, J.J.W.A. van Loon1*,
M.J.M.B. Pourquie3, F.T.M. Nieuwstadt3, J. Klein-Nulend1
1 (*DESC),OCB-ACTA-Vrije Universiteit, Dept
Oral Cell Biology, Van der Boechorststraat 7, NL-1081 BT, Amsterdam, The Netherlands
rg.bacabac.ocb.acta@med.vu.nl,
tel: +31-(0)20-4448687, fax: +31-(0)20-4448683 2VUMC-Vrije Universiteit,
Dept Clinical Physics and Informatics, Amsterdam, The Netherlands 3Delft
University of Technology, Lab. Aero & Hydrodynamics, Delft, The Netherlands
Microgravity has catabolic effects on the skeleton of astronauts.
This might be explained as resulting from an exceptional form of disuse under
near weightlessness conditions. Although poorly understood, the capacity of
bone tissue to adapt its mass and structure in response to mechanical demands
is recognized. This mechanical adaptation of bone is a cellular process that
involves the sensing of the applied mechanical loading and the appropriate response
to the effect of either making new bone or destroying old bone. The in vivo
operating cell stress derived from bone loading is likely the flow of interstitial
fluid along the surface of bone cells. It is possible that the mechanosensitivity
of bone cells is altered under near weightlessness conditions, and that this
abnormal mechanosensation contributes to the disturbed bone metabolism observed
in astronauts. An in vitro model utilizing dynamic fluid flow simulates
mechanical loading induced stress on bone cells. To test whether near weightlessness
decreases the sensitivity of bone cells for mechanical stress the in vitro
fluid flow system is to be downscaled to comply with the internal volume
requirements of EC type II/E experiment container of the Biopack
facility for a future space experiment. To bypass uncontrollable variables during
the transition from launch to orbit, half of the groups to be studied will be
treated with simulated gravity using an in-flight centrifuge facility.
The objective of this study is to provide a rheological characterization of
the fluid flow system under steady and dynamic flow regimes. This study
will develop a cell culture module that is used to provide further insight in
the mechanism of mechanotransduction in bone.
A theoretical characterization of the current parallel-plate fluid flow chamber
was performed using exact and numerical calculations for the assumptions of
non-turbulent laminar viscous flow. Exact solutions for the velocity profile
and wall shear stress were derived for varying width-to-height ratios, at a
fully developed steady flow regime. Similar calculation was done for an infinitely
wide parallel plates approximation at a fully developed oscillating flow regime.
Fluid flow was then simulated, using CFXTM (Computational
Fluid Dynamics Software by AEA Technology), to determine velocity patterns
using the downscaled flow chamber dimensions subjected to a rotating frame of
reference at the steady flow regime. Future experimental procedures using Laser
Doppler Velocimetry (LDV), pressure distribution measurements, and vibrations
analysis on the current parallel-plate fluid flow chamber will be performed
to verify the theoretical calculations.
The fully developed 2-dimensional velocity profile for a steady laminar viscous
flow across a rectangular duct assumes a paraboloidal surface for the mentioned
assumptions above (see figure 1b). Steady flow through parallel plates (i.e.,
for high height-to-width ratios), under the same assumptions, results into a
1-dimensional velocity profile giving a parabolic curve between the plates (see
figure 1b and figure 2a). These results imply that the wall shear stress on
the plate surface exposed to flow is homogenous except when very near one edge
of the flow chamber (see figure 1c). The theoretical results show that under
steady flow and a wall shear stress of 0.7 Pa, the velocity profile across the
channel of the parallel-plate flow chamber is parabolic in its fully developed
laminar viscous flow, for the current flow chamber dimensions and for a downscaled
version even under a rotating frame of reference (i.e., when inside a centrifuge).
Furthermore, the wall shear stress is determined to be simply proportional to
the flow with a time lag under the oscillating flow regime (see figure 2b).
Theses results show that the current flow chamber system can be downscaled for
use in space experiments to test the mechanotransduction of bone cells under
near weightlessness conditions using the same mechanical stimulation modes as
in the current flow chamber system.
Click here for
actual presentation.
STS-106 FLIGH RESULTS - EFFECTS OF MECHANICAL CULTURE CONDITIONS ON RENAL
CELL GENE EXPRESSION
TG Hammond, TJ Goodwin, E Benes, L Cubano, L Stodieck, J Genova,
J Love, T Baker, and PL Allen.
Tulane/VA Environmental Astrobiology Center, 1430 Tulane Avenue SL-45, New Orleans
LA 70112, USA, and VA Medical Center, New Orleans LA, BIOSERVE, University of
Colorado - Boulder, CO, Wyle Life Sciences, Houston TX, NASA Ames Research Center,
Moffett Field CA, and NASA Johnson Space Center, Houston TX. E:mail thammond@tulane.edu,
Phone: (504)-589-5279, FAX (504)-619-4046
Engineering optimization of suspension culture was largely undertaken by NASA engineers to model culture conditions in space flight, but may find its greatest utility in the carryover to ground-based applications, as suspension culture continues to be useful for production of many bioproducts, from antibodies to hormones. Optimizing mechanical culture conditions by minimizing shear and turbulence, led to a radical new (but simple) vessel design embodied in the rotating wall vessel: a horizontally rotating cylindrical culture vessel with a co-axial tubular oxygenator. We have shown that mechanical culture conditions have dramatic effects on gene expression profiling with space grown cells vastly different to ground based cultures. Although there are precedents for tiny perturbations in physical factors mediating huge gene expression changes, from heat shock proteins through vascular shear and bladder stretch, the key issue is whether responses to physical factors are general or a family of highly specific responses to different physical forces. To determine the patterns of gene expression and nuclear protein translocation, human renal epithelial cells were grown under various mechanical culture conditions. The pattern of gene expression and nuclear transcription factor translocation in cells flown on space shuttle mission STS-106 was compared to a battery of controls including ground based controls, controls vibrated to match shuttle launch vibration, controls centrifuged to match shuttle launch g, and optimized ground based suspension culture in the rotating wall vessel. Cells were fixed with RNA Later II two hours into the flight, RNA extracted on return to earth, and gene array analysis performed on Affymetrix U95 Human chips containing 12,000+ discrete gene sequences. The gene array analysis demonstrates changes in space distinct from rotating wall vessel, and the vibration and gravity controls. This data demonstrates that simple automated hardware allows completion of cell culture experiments in space with no astronaut time, and minimal power and space. Brief subtle changes in mechanical culture conditions had large effects on renal cell gene expression. The gene expression changes due to mechanical culture conditions are characterized by a few clusters common to all conditions, but mostly each mechanical stimulus, however subtle, has highly specific clusters of genes which change. Similarly, extraction of nuclear protein followed by SELDI Ciphergen analysis demonstrated unique patterns of translocation of nuclear transcription factors with different mechanical culture conditions. This study demonstrates that the unique dynamic operating conditions for cell culture in space identify distinct patterns of gene expression and nuclear protein translocation not obtainable by any other means. This also demonstrates the highly specific nature of the family of gene expression and transcription factor responses to physical stimuli.
ISSUES OF THERMAL-GRAVITATIONAL
MODELING SCALING OF TWO-PHASE FLOW AND HEAT TRANSFER
Delil A.A.M., National Aerospace Laboratory NLR, Space Division P.O.
Box 153, 8300 AD Emmeloord, The Netherlands Phone +31 527 248229; Fax +31 527
248210; E-mail: adelil@nlr.nl.
Multiphase flow, the simultaneous flow of the different phases (states of matter) gas, liquid and solid, strongly depends on the level and direction of gravitation, since these influence the spatial distribution of the phases, having different densities. Many current investigations concern the behaviour of liquid-solid flows (e.g. in mixing, crystal growing, or materials processing) or gas-solid flows (e.g. in cyclones or combustion equipment). However, of major interest for aerospace applications are the more complicated liquid-vapour or liquid-gas flows, that are characteristic for aerospace thermal control systems, life sciences systems and propellant systems. Especially for liquid-vapour flow in aerospace two-phase thermal control systems, the phenomena become extremely complicated, because of heat and mass exchange between the two phases by evaporation, condensation and flashing. Though a huge amount of publications (textbooks, conference proceedings and journal articles) concern two-phase flow and heat transfer, publications on the impact of reduced gravity are very scarce. This is the main driver for carrying out research in microgravity. The different heat and mass transfer research issues of two-phase heat transport technology for space applications are discussed. It is focused on the most complicated case of liquid-vapour flow with heat and mass exchange. Simpler cases, like adiabatic or isothermal liquid-vapour flow or liquid-gas flow, can straightforwardly be derived from the liquid-vapour case, as various terms in the constitutive equations can be set zero. The discussions pertain to the background of the research, a short general description of two-phase flow and heat transfer phenomena, and to the development supporting theoretical work. They include thermal/gravitational scaling of two-phase flow and heat transport in different sections of two-phase thermal control loops, including the various aspects of gravity level dependent two-phase flow pattern mapping and condensation. The outcomes of theoretical activities are compared with results of various experiments, carried out both on earth (one-g) and in micro-gravity environment.
INTERNATIONAL MICROGRAVITY PLASMA FACILITY:
EXPANDING THE FRONTIERS OF PHYSICS WHILE KEEPING SOCIETY IN MIND
Prof.dr.ir. Gerrit
Kroesen, Eindhoven University of Technology P.O. Box
513 5600 MB Eindhoven, The Netherlands tel : +31 40 247 43 57 fax : +31 40 245
60 50, e-mail: G.M.W.Kroesen@phys.tue.nl
Click here for actual presentation.
PHYSICO-CHEMISTRY OF ICES IN SPACE
Dr. H. J.Fraser, Prof. P. Ehrenfreund
Raymond and Beverly Sackler Laboratory for Astrophysics, Leiden Observatory,
Postbus 9513, 2300 RA, Leiden. Tel: (31) 71 527 5818, portable GSM: (31) 62
897 6531, Fax: (31) 71 527 5819, email: fraser@strw.leidenuniv.nl
Ices are observed throughout the universe:
on planetary bodies, comets, in the Interstellar Medium (ISM) and in protoplanetary
disks. We have little observational evidence about the exact formation mechanisms
or behaviour of ices in space or in planetary atmospheres. Consequently, it
is difficult to assess the chemical and physical role of ices associated with
their environment. It is clear that in the different regions where ices are
found, pressure, temperature, and gravitational conditions differ significantly
from those on Earth. Our current understanding of extraterrestrial ices relies
entirely on data accrued from laboratory-based studies (on Earth and therefore
at 1g). A new ESA Topical Team has been formed in answer to ESA Announcement
of Opportunity AO2000 (Basic and Applied Research in Physical Sciences in Space)
specifically to address these issues.
The team will study the effects of gravity on the physics and chemistry of molecular
ices. The team will also investigate the design of a new infrastructure, or
improvements to the existing hardware, incorporating a suitable cryogenic facility
and an ultra-high vacuum system, to study ices on the International Space Station.
The expertise of the team members and ground-based experiments in their laboratories
will define which instruments will be used in this study. The focus will be
on in situ analysis, e.g. IR spectrometers, X-ray diffraction instruments and
mass spectrometry. The currently planned facilities do not allow us to pursue
these research avenues. Such a facility will have multidisciplinary applications,
supporting microgravity research in crystal growth of ices and other solid refractory
materials, aerosol microphysics, light scattering properties of solid particles,
the physics of particle aggregates, radiation processing of molecular solids
and the characterization of retrieved samples (such as meteorites). In particular,
studying ices in microgravity conditions will provide us with fundamental data
on the nature of extraterrestrial ices.
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for actual presentation.
POSSIBILITIES AND RESULTS
OF THE GROUND RESEARCH FACILITIES IN THE NETHERLANDS
Jack J.W.A. Van Loon.
Dutch Experiment Support Center (DESC) at the Dept. Oral Biology, ACTA / Vrije
Universiteit, Amsterdam, van der Boechorststraat 7, 1081 BT The Netherlands.
Email: j.van_loon.ocb.acta@med.vu.nl.
With the upcoming International
Space Station (ISS) the future research possibilities for gravitational spaceflight
research is believed to be increased. To better understand the impact of weight
i.e. accelerations, i.e. gravity onto biological (and non-biological) systems
the traditional experiment set-up for such studies: one 1×g group and one microweight
group is far too limited. First of all we can start to perform hypergravity
experiments on ground. Centrifuges are easy and cost effective means to test
working hypotheses and will provide clues on hypogravity responses. Although
many researchers have taken this approach the majority of 'space researchers'
are still not fully aware of these possibilities. Within the Netherlands we
bundled various scientific efforts and initiatives in the area of gravitational
research through the 'Dutch Experiment Support Center', DESC. Among its tasks,
DESC promotes the use of 'ground based research' facilities and provides coordination,
support or access to the facilities. In this paper I will present the various
facilities that constitute DESC. These include hypergravity centrifuges for
cell biology (MidiCAR), animal physiology (AMC centrifuge) and the human rated
centrifuge at the Netherlands Aeromedical Institute. For microgravity (microweight)
simulations one may apply the classical (2D) clinostat, the Random Positioning
Machine (RPM), the Free Fall Machine (FFM) or the levitation magnet. Some research
results and examples of various facilities will be presented.
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for actual presentation.
IMMUNO-HISTOCHEMISTRY OF THE OTOLITH SENSORY EPITHELIUM AFTER PROLONGED
HYPERGRAVITY
R. J. Wubbels, H. N. P. M. Sondag, H. A. A. de Jong
Vestibular Department ENT, Academic Medical Center, University of Amsterdam,
PO Box 22660, 1100 DD Amsterdam, e-mail: r.j.wubbels@amc.uva.nl
It has been shown that an altered gravity level has distinct effects on different
parts of the vestibular system. Specific effects depend on the developmental
stage of the animal during exposure. Prolonged exposure of hamsters (starting
when they were 3 weeks old) to a hypergravity (HG) level of 2.5 g inside a centrifuge
has no effect on their otoconia (Sondag et al., Acta Otolaryngol 115: 227-230,
1995): calcium content, shape and size are the same as for controls. However,
when hamster embryos develop under HG conditions the otolith area with large
otoconia is decreased and the area with smaller otoconia is increased (Sondag
et al., Brain Res Bull 40: 353-357, 1996). Other studies showed that the number
of synapses on utricular hair cells (Ross, J Vestib Res 3: 241-251, 1993), and
in the vestibular nucleus (Johnson et al., J, Brain Res 106: 205-221, 1976;
Bruce & Fritzsch, J Gravit Physiol 4: P59-62, 1997) is affected by gravity
level.
The objective of our study was to determine the effect of prolonged hypergravity
on the vestibular epithelium of the rat. Because the otolith organs function
as linear acceleration detectors possible effects are primarily expected in
the saccule and in the utricle. Four weeks old rats were transferred to the
centrifuge and stayed there for 9 months. Two cytoskeletal proteins, actin and
tubulin, were immuno-histochemically labeled. Scans of the utricle and the saccule
were obtained with a confocal microscope and analyzed.
Examples of utricles from a HG and a normal gravity (NG) rat are shown in Fig.
1. Depending on the focal plane of the scan, several details of the hair cells
can be discerned: the bundles of stereocilia, and the actin belt of tight junctions
between hair cells and supporting cells. From each utricle two samples are shown,
with focal plane II 2 m m apical of focal plane
I. Fig. 2 shows the tubulin-labeled structures of the same utricles (and focal
planes) as in Fig. 1. Structural details are the kinocilia, and the tightly
packed microtubules in the ‘neck’ region of type-I hair cells (bright white
spots).
In general, the maculae of HG rats appear to be intact. The honeycomb-like structure
(Fig. 1) formed by the tight junctions’ actin belts, was analyzed with respect
to area (A (m m2)) and roundness
(R=P2/(4× p
× A× 1.064;
P=perimeter (m m)). Means ±
SD are listed in Table 1. For the utricles of HG rats, the area enclosed by
the actin belts is a little smaller (5%) and their circumference appears to
be somewhat more irregular. For the saccule no significant differences were
found. The preliminary results of our immuno-histochemical study suggest that
the effect of prolonged HG exposure on mature otolith sensory epithelia (of
the rat) is probably small. We also performed the experiment in which gestation
occurred under 2.5 g conditions, but analysis of the data is still in progress.
Click here for
actual presentation.
|
Table 1 |
Area (m m2) |
Roundness |
||
|
HG |
NG |
HG |
NG |
|
|
saccule |
21.1 ± 7.6 |
21.5 ± 6.3 |
1.310 ± 0.155 |
1.330 ± 0.137 |
|
Not significant |
not significant |
|||
|
utricle |
20.7 ± 7.1 |
21.8 ± 7.0 |
1.337 ± 0.162 |
1.304 ± 0.145 |
|
p < 0.005 |
p << 0.001 |
|||
Figure 1
Figure 2
MODELLING (SPACE) MOTION SICKNESS
Jelte E. Bos, Eric L. Groen, Willem Bles
TNO Human Factors, P.O. Box 23, 3769 ZG Soesterberg, the Netherlands. e-MAIL:
Bos@tm.tno.nl, Phone: +31 346 356371, Fax:
+31 346 353977
Gravity plays a key role in the genesis
of motion sickness, and obviously also in space motion sickness. We previously
showed (Groen et al., NL-Gravity Symposium December 10, 1999) that head movements
elicited after a long duration centrifugation run were provocative with
respect to motion sickness when gravity changed with respect to the head. We
then also showed that the symptoms very much resembled those of space sickness
as we were able to observe in eight astro- and cosmonauts. Based on these, and
other observations, we developed a model based on observer theory that explains
and predicts motion sickness characteristics. In this model that basically describes
the control of motion, the vestibular apparatus in the inner ear senses the
specific force, which acceleration has to be resolved into a component due to
gravity and another due to motion. Only the latter component, of course, is
needed for the control of motion, for otherwise we might feel like an astronaut
in only a few minutes when just in rest on the earth surface: Integration over
time of the earth gravitational acceleration will give a displacement of ½gt2
» 440km, with g=9.81m/s2 and
t=300s. Obviously this is not the case (we feel at rest under such a
condition), and hence our central nervous system is indeed capable of filtering
out gravity from the sensed specific force. In the proposed model, this gravity
component may be in conflict with another estimate of gravity as resolved by
an internal model, and it is postulated that this conflict correlates with motion
sickness. For several types of motion this hypothesis has been validated now,
and some typical examples will be discussed.
To further validate this model in hypo- and hypergravity conditions, as relevant
for future space missions including the application of artificial gravity during
space flight to reduce bone loss, for example, we are looking forward to the
use of an unrestricted 3D gimbals-vertical oscillator-sled-centrifuge, projected
for 2002 at TNO Human Factors in Soesterberg. With this apparatus, called Desdemona
(see figure), we will not only be able to further validate the proposed model,
but also to answer many more questions concerning (psycho)physiological effects
of centrifugation, altered gravity levels and g-transitions during interplanetary
space flight.
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for actual presentation.
RESEARCH PLANS FOR LIFE AND PHYSICAL
SCIENCES
Dr. Marc Heppener,
European Space Agency, ESA / ESTEC (MSM). P.O. Box 299, 2200 AG Noordwijk, The
Netherlands. tel : +31 71 565 5117, e-mail: marc.heppener@estec.esa.int
(Click here for actual presentation). NOT ACTIVE YET
MICROGRAVITY RESEARCH WITHIN THE NETHERLANDS
Dr. Rolf de Groot.
Space Research Organisation of the Netherlands, SRON, Sorbonnelaan 2, 3584 CA,
Utrecht, The Nethalnds. Tel: 31 30 253 5656 e-mail: r.p.de.groot@sron.nl
Click here for actual presentation.
THE ASTRONAUT MICROGRAVITY
MODEL FOR THE ASSESSMENT OF DEEP MUSCLE FIBRE ATROPHY IN ETIOLOGY OF LOW BACK
PAIN.
Chris J. Snijders Erasmus University Rotterdam, Faculty of Medicine
and Health Sciences, Department of Biomedical Physics and Technology. Rotterdam.
E-mail: Snijders@bnt.fgg.eur.nl.
Background: Musculoskeletal disorders form the single most expensive disease in society. Low back pain (LBP) forms the greatest contribution and despite ongoing research the incidence of LBP and the costs of its influence on society continue to rise. For 90% of the patients, the aetiology of the pain remains obscure. The applicants developed a biomechanical model on the transfer of gravity load through the lumbar spine and pelvis. The model predicts a significant stability effect of deep muscle forces which is shown to be effective in the treatment of low back pain. This deep muscle corset was not included in earlier space studies. The present research proposal also refers to the direct relation between change of spinal length and intradiscal pressure found in recent tests on subjects in different postures and exercises. Objectives: Microgravity forms a unique situation for our objectives: a) to verify that without gravity load deep muscles show functional disuse and atrophy and b) to implement increase of disc height in the modeling of load transfer through the lumbosacral junction. Aim of the study is a scientific and a hardware contribution to the solving of LBP problems in the general population and in astronauts. The aim of the hardware definition is application in the general physical therapy clinic. Study design: This research proposal includes non-invasive measurements and pain assessment in astronauts prior to, during and after flight. In a first flight muscle and spine parameters are measured without, and in a second flight with specific exercises. For measurements and specific exercises hardware will be selected and/or developed. Hypotheses: Microgravity decreases the tonic loading function of the transversus abdominis and multifidus muscle, which results in functional disuse and atrophy. Atrophy of deep muscles introduces lack of protection of lumbopelvic joints against loading by force exertion and exercises during flight, which results in an episode of LBP. Increase of disc height during flight is related to change of intradiscal pressure and tension in collagenous tissue structures, which contributes to LBP injury risk.
WHAT DO WE KNOW ABOUT
THE ORIGIN OF LIFE?
Alan W. Schwartz. University Nijmegen, Fact. Biology, Dept. Exobiologie,
Toernooiveld 1, 6525 ED, Nijmegen, NL. Tel: 31 24 3652455. E-mail: alan@sci.kun.nl.
EARTH'S EARLIEST SEDIMENTARY
BASINS, A GOOD GEOLOGICAL CONTRIBUTION TO ASTROBIOLOGY
Wouter Nijman and Sjoukje T. De Vries Dept. of Sedimentology, Institute
of Earth Sciences, Utrecht University, Postbus 80021, 3508TA UTRECHT, The Netherlands;
e-mail : wnijman@geo.uu.nl; stdevries@geo.uu.nl.
Earth's Earliest Sedimentary Basins are the target of an international project organized between Utecht University and Cape Town University, with a participation from several other institutes and researchers. This EEB-project envisages the unravelling of the formation and evolution of the first sedimentary basins and environments from as many points of view as geologically possible. It concerns the Early Archaean, between 3.5 and 3.3 Ga. That is the period of the evolution of the earth before geological processes such as plate interaction, differentiation in oceans and continents, became closely comparable to those well-known from the geologically better accessible younger earth history. The earliest sedimentary basins, rocks of which are exposed in Australia and South Africa, were the sites of interference of processes in the lithosphere, hydrosphere, atmosphere, and biosphere of the primordial Earth. A better understanding of these sedimentary environments can contribute to the knowledge of the conditions under which prokaryotic life evolved. The first results indicate that the earliest sedimentary basins are located in gravitational collapse structures of the size encountered on Venus and that the hot and watery environment, with abundant hydrothermal activity may have been comparable to that supposed to have existed on Mars during its early stages of evolution. This makes them a promising target for cooperation between geologists, planetologist and astrobiologists.
ASTROBIOLOGY WITH ESA
SCIENCE MISSIONS
Bernard H. Foing. Head, Research Division ESA Space Science, Department
ESTEC/SCI-SR, postbus 299, NL- 2200 AG Noordwijk EUROPE. E-mail: Bernard.Foing@esa.int
Key questions of astrobiology
can be addressed by several space missions from the ESA Science Horizons 2000
Programme, such as:
- How do solar and stellar systems form ? (with ISO, FIRST, SMART-1, Rosetta,
Colombo, Gaia)
- Geological evolution of terrestrial planets (with Living planet, Mars-express,
SMART-1, Bepi-Colombo to Mercury)
- Interstellar Complex organic chemistry (with ISO, ISS/EXPOSE, FIRST, Rosetta)
- Co-evolution of Earth-Moon, impacts life frustration (with SMART-1, Bepi-Colombo)
- How to detect other solar systems and habitable zones (with space photometry,
COROT, Eddington, Gaia, Darwin)
- Early Earth and alternative environments (Huygens/Cassini and Mars-express)
- Signature of biosphere and photosynthesis evolution (living Planet missions,
Darwin)
- Water on Mars (with orbiter instruments on Mars Express)
- Exobiology lander experiments (with Beagle-2 lander on Mars-Express)
- Study of biomarkers and delivery of organics (with Mars-express and future
missions)
We shall review how the results from these ESA missions can be exploited in
synergy to contribute to progress in astrobiology, and the perspectives for
the next phases of solar system exploration, and life expansion beyond Earth.
(Click here for actual presentation).
NOT ACTIVE YET
GAIA
Peter Westbroek, University of Leiden p.westbroek@chem.leidenuniv.nl.
The Earth is a highly anomalous object in the solar system, because of (1) the uninterrupted presence of a prominent biosphere for 3.8 Ga; (2) the abundance of liquid water; (3) the fact that the atmospheric composition is far removed from thermodynamic equilibrium; and (4) the continued operation of the rock cycle. These characteristics are intimately coupled. For instance, life critically depends on the rock cycle for nutrient retrieval and waste disposal. Also, the aerobic atmosphere resulted from the combination of photosynthesis and on the creation of accommodation space for the burial of organic carbon. A top-down systems approach to life and the earth suggests the existence of a hierarchical order of organization, in particular at the molecular, organismal, ecosystem and global levels of organization. The calcium silicate carbonate cycle is an example of global organization. It contains a biologically assisted global thermostat. The term Gaia refers to the emergent properties of multiple global feedbacks, few of which are known. Although our present understanding precludes a scientifically operational characterization of this system, Gaia remains a useful concept. The term reminds us of our ignorance of the planet that we tend to find normal. We may characterize Gaia Science as Earth System Science with an asterisk.
THE SEARCH FOR EXTRA-TERRESTRIAL
MICROBIAL LIFE. POSSIBILITIES AND PITFALLS
Henk W van
Verseveld1, Boris M van Breukelen2, Wilfred FM Röling*.
Vrije Universiteit,
Faculties of Biology1 & Earth Sciences2, Department
of Molecular Cell Physiology, Section Molecular Microbial Ecology, De Boelelaan
1087, NL-1081 HV Amsterdam, NL. E-mail: verseveld@bio.vu.nl
*present address:
Fossil Fuels and Environmental Geochemistry, University of Newcastle upon Tyne,
Newcastle upon Tyne, NE1 7RU, United Kingdom.
The
search for extra-terrestrial microbial life can only be successful when our
assumptions about the origin and evolution of life on Earth can be transposed
to other planets, like Mars, or possible life-bearing moons, like Europe. On
Earth, life most probably started in a "RNA-world" (see presentation
of Alan Schwartz), and later developed in the present "DNA-world"
as we know it. The first pitfall is clear immediately: In a non-Earth situation
the evolution of life could have ended in the "RNA-world" and all
detection methods for the presence of biological activity could be non-valid
(see also presentation of Bernard Foing).
Assuming that the
development of life is an intrinsic characteristic of our Universe, and that
the laws for start and development of life are thus valid throughout the Universe
the most optimal strategy then is searching for RNA and DNA in combination with
expected "in situ" physiological activities.
Life in general needs
driving forces like sunlight (photosynthesis) and/or (an)organic energy rich
molecules. Energy is made useful via respiration (aerobic and anaerobic). On
Earth respiration developed before the "oxygen revolution" and recently
it has been hypothised that oxidized metal-species (like Fe3+) have
been served as first electron acceptors. The following equation shows the reaction
with hydrogen as the electron donor:
On planets or moons that have developed life, but apparently do not show the presence of oxygen, life could have evolved not further than the metal-reducing stage, or have fallen back to the metal-reducing stage after all oxygen is depleted. When this is true, the most sensible approach for "in situ" physiological activity measurements would be the determination of free Gibbs energy for metal-reducing reactions, in combination with the presence of autotrophic CO2-fixing reactions. The free Gibbs energy for the above reaction will be:
Such a reaction will only
occur on Earth when the Gibbs free energy for the reaction is below a minimum
threshold value (-7 to -20 kJ/mol H2).
As an Earthly example
the techniques involved in the search for anaerobic Fe-reducing environments
and Fe-reducing micro-organisms in Dutch aquifers will be presented.
A wide variety on
environmental situations is present on Earth: From extreme hot to extreme cold,
minimal water to oceans of water, extreme acid to extreme alkaline etc. All
these environments contain at least microbial life. Similar environments as
present on Mars or Europe can be found on Earth and the capacities of life as
evolved here can be researched in depth to get an indication of what to expect
extra-terrestrially.
Click here
for actual presentation.
EVOLUTIONARY POLYMER MATERIAL IN CHEMICAL
INDUSTRY AND ASTROBIOLOGY
Prof.Dr.Ir. J.G.E.M Fraaije
Soft Condensed Matter Group, Leiden Institute of Chemistry E-MAIL: j.fraaije@chem.leidenuniv.nl
In the last century, the chemical industry has produced a different polymer materials, with many diverse applications in the biomedical and biopharmaceutical sciences, but also in down-to-earth engineering plastics and other polymer commodities. Yet this bewildering variety is based on only a few tens of basic building blocks: the industrial "amino acids". A hot topic in the design of new polymer materials is computer-assisted combinatorial chemistry, where one tries to mimick an evolutionary process by connecting computer models to high-throughput screening methods. The hottest topic, and the greatest challenge for the future, is to develop purely synthetic self-reproducing materials which adapt by Darwinian evolution. If such systems can be made on Earth, then it should be possible to find them somewhere else also.
ASTROBIOLOGY AND MARS
EXPRESS
Agustin Chicarro. ESA/ESTEC, Space Science Dept., Postbus 299, 2200
AG Noordwijk, Netherlands. achicarr@estec.esa.nl.
Fax: +31-71-5654697.
The ESA Mars Express mission
will be launched in June 2003 from Baikonur onboard a Soyuz rocket. The mission
comprises an orbiter spacecraft to be placed in a polar elliptical martian orbit,
with closest approach of 250 km and a mission lifetime of one martian year (687
days), and the small Beagle-2 lander to arrive at Isidis Planitia in December.
In addition to studying the surface, subsurface, atmosphere and environment
of Mars, the main themes of the mission are the identification of water and
of possible signs of life in the history of the planet. The specific scientific
investigations of the orbiter are: global high-resolution imaging and super-resolution
imaging of selected areas, global IR mineralogical mapping, global atmospheric
circulation study and mapping of the atmospheric composition, sounding of the
subsurface structure down to the permafrost, study of the interaction of the
atmosphere with the surface and with the solar wind as well as radio science.
The goals of the Beagle-2 lander are: geology, geochemistry, meteorology and
exobiology of the landing site, using a robotic arm and other devices such as
a 'mole' capable of subsurface sampling. International collaboration is very
much valued to diversify the scope and enhance the scientific return of the
mission, and in particular close cooperation between the Japanese Nozomi mission
and Mars Express, since both the orbits and the scientific investigations are
very complementary to each other. For more details on the Mars Express mission
and its Beagle -2 lander: http://sci.esa.int/marsexpress/
and http://www.beagle2.com/
(Click here for actual presentation).
NOT ACTIVE YET
ESA LIFE SCIENCES, EXOBIOLOGY
AND EXPLORATION.
D. Schmitt and P. Clancy.
European Space Agency, ESA
Directorate of Manned Spaceflight and Microgravity (ESA/MSM) P.O. Box
299, 2200 AG Noordwijk, The Netherlands.
dschmitt@estec.esa.nl.
ESA's Life Sciences activities
have been involved in promoting exobiological research since the 1980's when
the Exobiology and Radiation Assembly (ERA) started development. ERA flew on
the 11 months EURECA mission in the early 1990's and provided results on the
exposure of invertebrates, micro-organisms, organics and fungi to space conditions
(UV, radiation and vacuum). In parallel ESA's BIOPAN facility has flown and
continues to fly on the Russian FOTON recoverable capsule and provides exposure
times of about 2 weeks. ESA's EXPOSE facility will provide similar experimental
conditions for long-duration exposure on the external locations of the International
Space Station (ISS). These three ESA facilities provide valuable research data
on the survivability and damage/ repair mechanisms of organics, micro-organisms
and invertebrates to space conditions.
Based on recommendations of its advisory groups (LSWG and LPSAC), in 1996 ESA
started Science Team studies on the search for life in the Solar System and
particularly on Mars. The Science Team specifically recommended the development
of an exobiology exploration package to be placed on the Martian surface, drill
below the sterile layer and look for signs of extinct life. Two Phase A studies
were subsequently carried out with industry to define the technical realities.
ESA presently prepares a Phase A/B study of this "Exobiology Package" once a
clearer picture of upcoming flight opportunities emerges.
In late 2000 ESA started preparation of a Planetary Exploration Initiative now
designated "Aurora". Three ESA Directorates, namely Strategy, Space Science
and Manned Spaceflight and Microgravity are leading the activity. The present
planning is to present a programme proposal for an initial phase (~3 years)
to the November 2001 Ministerial Council.
In order to define the scientific rationale an Exploration Scientific Expert
Group (ESEG), including life scientists, has been appointed. To give input to
this experts group a call for ideas has been issued and a workshop on "Robotic
and Human Exploration of the Solar System" has been held.
A total of 291 ideas (including long-term vision and short term initiatives)
have been received and analysed. The main scientific objectives from a European
perspective resulting from this preliminary review were:
Planetary protection Finally,
it is planned that a future Life and Physical Sciences Programme also intended
for approval at the November 2001 Ministerial Conference will include a programme
element on "Support to Planetary Exploration" as a complementary activity including
life science specific studies, simulations and ground based supporting work.
Click here
for actual presentation.
CHARACTERIZING EARTH-LIKE
PLANETS ORBITING NEARBY STARS AND DARWIN, ESA's INFRARED SPACE INTERFEROMETER
MISSION
Dr. Huub Röttgering
Leiden Observatory, P O Box 9513
2300 RA Leiden, The Netherlands. Tel: (31) 715275851 Fax: (31) 715275819 E-mail:
rottgeri@strw.leidenuniv.nl
Characterizing Earth-like
planets orbiting nearby stars and Darwin, ESA's InfraRed Space Interferometer
mission '' Important aims of ESA's InfraRed Space Interferometer mission ``Darwin''
is to detect Earth-like planets orbiting nearby stars, analyze their characteristics,
and determine the composition of their atmospheres and -- their capability to
sustain life as we know it. (The second aim is to provide detailed images of
astrophysical objects.) In this talk we will first discuss the tremendous success
of the techniques that are currently being used to detect Jupiter-like planets
orbiting nearby stars. Subsequently, we will discuss the problem of how to detect
and characterize ``exo-Earths'' and how the Darwin project attempts to solve
this problem using 6 free flying space crafts carrying out interferometric measurements
in the thermal infrared. Finally, we discuss the schedule that should lead to
the launch of Darwin around 2014.
Click here
for actual presentation.
ESA EXOBIOLOGY ON UNMANNED "FOTON"
CAPSULES
R. Demets, P. Baglioni.
ESTEC(MSM-GMS), Keplerlaan 1, 2201 AZ Noordwijk, the Netherlands Rene.Demets@esa.int
tel:071-565 5081 fax: 071-565 4293
Since 1994, exobiological experiments
have regularly been performed by ESA-affliated investigators on Russian recoverable
capsules of the "Foton" class. The experiments came in three different
categories, identified by the nicknames SURVIVAL, DUST and STONE.
In the SURVIVAL experiments (investigators: G. Horneck, R. Mancinelli, L. Nevzgodina
and others), the compatibility of terrestrial life forms with the harsh space
environment was investigated. The test objects included plant seeds, bacterial
spores and halophilic microbes which - in ESA's Biopan - were subjected to a
mixture of solar UV, space radiation, space vacuum, weightlessness and extreme
temperatures. The plant seeds and the salt-loving microbes survived remarkably
well. The bacterial spores retained their viability as well, but only if shielded
against solar UV.
In the DUST experiments (investigators: A. Brack, B. Barbier and others), the
stability of amino acids and peptides required for the emergence of life was
tested under exposure conditions similar to those of SURVIVAL. After two weeks
in space, some photo-degradation was measurable. In test samples mixed with
clay, the effect of solar UV was only partly halted, which suggests that the
fine-grained dust particles from interstellar space might not provide adequate
protection against solar irradiation.
The STONE experiment (investigators: A. Brack, G. Kurat and others) is a study
about the effects of the entry environment on meteorites and on life it may
contain. STONE flew for the first time in 1999 on Foton-12. Pieces of rock,
acting as ‘artificial meteorites’, underwent entry into the Earth’s atmosphere
embedded in the heat shield of the Foton capsule. The goal was to find out why
sedimentary rocks do not seem to survive atmospheric entry. The experiment demonstrated
that sedimentary rocks can in fact survive the trip, but their chemical
and physical properties become changed to the extent that after landing on Earth,
they quickly fall apart. In follow-on STONE experiments, similar rocks will
be pre-loaded with defined organics and microbes to investigate to what extent
the building blocks for life, as well as life itself, are affected by the entry
environment.
Click here
for actual presentation.
|
year |
mission |
Survival |
Dust |
Stone |
|
1994 |
Foton-9 |
x |
x |
|
|
1997 |
Foton-11 |
x |
x |
|
|
1999 |
Foton-12 |
x |
x |
|
|
2001 |
Resurs F (planned) |
x |
||
|
2002 |
Foton M-1 (planned) |
x |
x |
DETECTION OF PREBIOTIC MOLECULES
IN UV-PHOTOPROCESSED INTERSTELLAR ICE ANALOGS
Guillermo M. Muñoz Caro, Willem A. Schutte, J. Mayo Greenberg
Uwe Meierhenrich Affiliation: Raymond and Beverly Sackler Laboratory for Astrophysics
at Leiden Observatory, 2300 RA Leiden, The Netherlands E-mail address: munoz@strw.leidenuniv.nl
Phone: 31 71 527 5809 Fax: 31 71 527 5743
Interstellar organic material was delivered
to the early Earth by comets, meteorites and small particles. The role these
extraterrestrial species played on the origin of life is an intriging issue
of which very little is known (Oro' 1961).
The thermal- and UV-photoprocessing of interstellar ices (H2O, CO, CO2, CH3OH
and NH3) are simulated in a vacuum system (P equiv. 10^-7 torr) at T equiv.
12 K.
As a result, a large variety of products is formed (Agarwal et al. 1985, Briggs
et al. 1992, Bernstein et al. 1995), many of them of biological interest such
as glycine, urea, aldehydes, carboxylic acids, etc. Since comets are presumably
formed of interstellar dust particles, these organics might have been delivered
to our young planet starting a set of reactions that could have triggered the
appearance of life on Earth.
Hexamethylenetetramine (C6H12N4, HMT) is one of the dominant products of ice
photolysis if CO or CH3OH and NH3 are involved. Acidic solution of HMT leads
to the formation of amino acids. The production of HMT as a function of the
UV dose and formation temperature (equiv. 300 K) are reported. This constraints
the search for HMT to environments where some UV field is present and the ices
are exposed to such high temperatures. HMT could form in the disks of young
stellar objects (YSOs) near the star. Also the first identification of HMT derivatives
is reported, as a result of complex chemistry that goes beyond HMT, containing
-CH2OH, -NH- and -CHO groups, all of prebiotic interest.
Click
here to download the actual presentation (PDF file, 87 kb)
EVOLUTION OF ORGANIC MATTER IN SPACE,
FROM DEEP SPACE TO EARLY PLANETS
Richard Ruiterkamp. Raymond and Beverly Sackler Laborato for Astrophysics
at Leiden Observatory, The netherlands Tel: 31 (0)71 5275812 fax: 31 (0)71 5275819.
E-mail: Richard.Ruiterkamp@strw.LeidenUniv.nl.
The sun, the planets and ulimately life
on earth are part of the cosmic carbon cycle. Large dense molecular clouds in
the interstellar medium drive the collaps of clumps of matter into stars. Many
of these new stars form planetary systems that may also contain bodies such
as comets, asteroids, meteorites. The conditions that prevail during the birth
stages of a star drive a complex chemistry that is aparent by the more than
130 detected molecules in these clouds, most of them carbonaceous in nature.
Polycyclic Aromatic Hydrocarbons are believed to be the most abundant free organic
moleculs in space and to be formed in the outer atmosphere of carbon stars,
or by shock fragmentation of carbonaceous material. The Sackler Laboratory for
Astrophysics at Leiden University is currently involved in a long duration exposure
experiment on ISS. We will present a short overview of the experimental parameters
and obtained and expected results. Comets, asteroids, meteorites and Interplanetary
Dust Particles (IDPs) are a source of complex organic material such as aminoacids
and may have played a crucial role in the onset of life in our solar system.
Impact of these bodies on the early planets has been, and still is, a major
contribution to the chemical inventory on the surfaces and atmospheres of planets.
However on the surface of Mars no traces of organic materials could be detected.
It is known that oxidation by radicals is the main destruction mechanism. How
these processes effect subsurface materials is less well known. In order to
simulate the current and ancient Martian surface and atmospheric conditions
our group is involved in a Martian simulation experiment. We will present the
expermental setup and parameters of this Mars Simulation Chamber and discuss
the expected results.
Click here
for actual presentation.
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