ABSTRACT
Space experiments provide a unique opportunity to advance our knowledge of how plants respond to the space environment, and specifically to the absence of gravity. The European Modular Cultivation System (EMCS) has been designed as a dedicated facility to improve and standardise plant growth in the International Space Station (ISS). The EMCS is equipped with two centrifuges to perform experiments in microgravity and with variable gravity levels up to 2.0 g. Seven experiments have been performed since the EMCS was operational on the ISS. The objectives of these experiments aimed to elucidate phototropic responses (experiments TROPI-1 and -2), root gravitropic sensing (GRAVI-1), circumnutation (MULTIGEN-1), cell wall dynamics and gravity resistance (Cell wall/Resist wall), proteomic identification of signalling players (GENARA-A) and mechanism of InsP3 signalling (Plant signalling). The role of light in cell proliferation and plant development in the absence of gravity is being analysed in an on-going experiment (Seedling growth). Based on the lessons learned from the acquired experience, three preselected ISS experiments have been merged and implemented as a single project (Plant development) to study early phases of seedling development. A Topical Team initiated by European Space Agency (ESA), involving experienced scientists on Arabidopsis space research experiments, aims at establishing a coordinated, long-term scientific strategy to understand the role of gravity in Arabidopsis growth and development using already existing or planned new hardware.
Subject(s)
Plant Development , Spacecraft , Arabidopsis/physiology , Equipment Design , EuropeABSTRACT
Ultradian movements of Arabidopsis thaliana rosette leaves were discovered and studied under microgravity conditions in space. Weightlessness revealed new facets of these movements. The European Modular Cultivation System (EMCS) was used in a long-term white-light, light-darkness (LD; 16 : 8 h) experiment on the International Space Station (ISS). Leaves reacted with slow up or down movement (time constant several hours) after transitions to darkness or light, respectively. Superimposed movements with periods of c. 80-90 min and small-amplitude pulsed movements of 45 min were present in the light. Signal analysis (fast Fourier transform (FFT) analysis) revealed several types and frequencies of movements. Identical phase coupling was observed between the 45-min movements of the leaves of one plant. In darkness, movements of c. 120-min period were recorded. The EMCS allowed 0-g to 1-g transitions to be created. Leaves on plants germinated in microgravity started a negative gravitropic reaction after a delay of c. 30 min. Leaves grown on a 1-g centrifuge reacted to the same transition with an equal delay but had a weaker gravitropic response. The experiments provide unequivocal demonstrations of ultradian, self-sustained rhythmic movements in A. thaliana rosette leaves in the absence of the effect of gravity.
Subject(s)
Arabidopsis/physiology , Gravitropism , Movement , Periodicity , Plant Leaves/physiology , Weightlessness , Centrifugation , Darkness , Light , Space Flight , Time FactorsABSTRACT
In a microgravity experiment onboard the International Space Station, circumnutations of Arabidopsis thaliana were studied. Plants were cultivated on rotors under a light:dark (LD) cycle of 16 : 8 h, and it was possible to apply controlled centrifugation pulses. Time-lapse images of inflorescence stems (primary, primary axillary and lateral inflorescences) documented the effect of microgravity on the circumnutations. Self-sustained circumnutations of side stems were present in microgravity but amplitudes were mostly very small. In darkness, centrifugation at 0.8 g increased the amplitude by a factor of five to ten. The period at 0.8 g was c. 85 min, in microgravity roughly of the same magnitude. In white light the period decreased to c. 60 min at 0.8 g (microgravity value not measurable). Three-dimensional data showed that under 0.8 g side stems rotated in both clockwise and counter-clockwise directions. Circumnutation data for the main stem in light showed a doubling of the amplitude and a longer period at 0.8 g than in microgravity (c. 80 vs 60 min). For the first time, the importance of gravity in amplifying minute oscillatory movements in microgravity into high-amplitude circumnutations was unequivocally demonstrated. The importance of these findings for the modelling of gravity effects on self-sustained oscillatory movements is discussed.
Subject(s)
Arabidopsis/growth & development , Extraterrestrial Environment , Plant Stems/growth & development , Space Flight , Weightlessness , Earth, Planet , Gravitropism , Movement , Rotation , Time FactorsABSTRACT
Members of the genus Echinops in the family of Asteraceae are widely used in Ethiopian herbal medicine for the treatment of various diseases and illness such as migraine, diarrhea, heart pain, different forms of infections, intestinal worm infestation and hemorrhoid. Hydroalcoholic extracts of the root, flower head, leaf and stem of Echinops ellenbeckii O. Hoffm. and Echinops longisetus A. Rich were investigated for their chemical constituents and biological activities. The presence of alkaloids, saponins, phytosterols, polyphenols and carotenoids in the different parts of the plants was observed whilst anthraquinones were not detected. The leaf extracts of both plants and stem extract of E. longisetus showed strong inhibitory activity against cultures of Staphylococcus aureus. None of the extracts were found to be active against Gram-positive organisms. The flower extract of E. ellenbeckii showed strong inhibitory activity against Candida albicans. Root and flower extracts of the plants investigated showed lethal activity against earthworms. Moreover, the extracts of the roots of both plants showed molluscicidal activity against schistosome-transmitting snail hosts. The biological activities observed were dose dependent.
Subject(s)
Antifungal Agents/pharmacology , Asteraceae , Candida albicans/drug effects , Phytotherapy , Plant Extracts/pharmacology , Animals , Anthelmintics/administration & dosage , Anthelmintics/pharmacology , Anthelmintics/therapeutic use , Antifungal Agents/administration & dosage , Antifungal Agents/therapeutic use , Ethiopia , Flowers , Medicine, African Traditional , Mollusca/drug effects , Molluscacides/administration & dosage , Molluscacides/pharmacology , Molluscacides/therapeutic use , Oligochaeta/drug effects , Plant Extracts/administration & dosage , Plant Extracts/therapeutic use , Plant Roots , Schistosomiasis/prevention & control , Snails/drug effects , Snails/parasitologyABSTRACT
As a link in the preparation of the MULTIGEN experiment, which will take place on the International Space Station, ground based studies of the gene expression in Arabidopsis thaliana were performed. Microarray technology was used to screen Arabidopsis seedlings exposed to simulated hypogravity on a Random Positioning Machine and a 1 x g control sample. This screening showed differential expression in 177 out of approximately 8000 genes. Some of these genes can be grouped into functional categories, e.g. general metabolism, biogenesis of cellular components, cellular transport and transport facilitation, and cell rescue and defense response. However, about 50% of the genes encode proteins with unknown function. Based on the above results a new "in-house" cDNA microarray was constructed. Some of the selected genes on this microarray (e.g. Xyloglucan endotransglycosylase, At2g18800) showed differential expression both in Arabidopsis exposed to hypergravity and simulated hypogravity by use of a centrifuge and a Random Positioning Machine.
Subject(s)
Arabidopsis/genetics , Gene Expression Regulation, Plant/physiology , Genes, Plant/physiology , Weightlessness Simulation , Centrifugation , Hypergravity , Oligonucleotide Array Sequence Analysis , Plant Shoots/genetics , Rotation , Seedlings/geneticsABSTRACT
In 1996, the production of Achillea millefolium L. at different locations in Norway was investigated with regard to the developmental stage. The oil content differed greatly between the vegetative stage (0.13%) and the stage of full bloom (0.34%). Changes in the composition of yarrow essential oil were found to be related to maturation of the plant, with increasing amounts of monoterpenes in relation to the sesquiterpene. However, a clear trend could be detected only for the monoterpenic compounds with increasing levels of alpha- and beta-pinene and alpha-thujone and decreasing levels of sabinene, borneol, and bornyl acetate. Previously reported as major compounds, chamazulene and germacrene D could be found only in insignificant amounts. A solid-phase microextraction (SPME) procedure was applied for screening of the terpenic composition. Sesquiterpenic compounds such as beta-bisabolene, alpha-bisabolol, and delta-cadinene were detected in substantial amounts by SPME in contrast to the steam-distilled samples.
Subject(s)
Oils, Volatile/chemistry , Plants, Medicinal/chemistry , Gas Chromatography-Mass Spectrometry/methods , Norway , Terpenes/analysisABSTRACT
Results from experiments using protoplasts in space, performed on the Biokosmos 9 satellite in 1989 and on the Space Shuttle on the IML-1-mission in 1992 and S/MM-03 in 1996, are presented. This paper focuses on the observation that the regeneration capacity of protoplasts is lower under micro-g conditions than under 1 g conditions. These aspects have been difficult to interpret and raise new questions about the mechanisms behind the observed effects. In an effort to try to find a key element to the poor regeneration capacity, ground-based studies were initiated focusing on the effect of the variable organization and quantity of corticular microtubules (CMTs) as a consequence of short periods of real and simulated weightlessness. The new results demonstrated the capacity of protoplasts to enter division, confirming the findings in space that this was affected by gravity. The percentage of dividing cells significantly decreased as a result of exposure to simulated weightlessness on a 2-D clinostat. Similar observations were made when comparing the wall components, which confirmed that the reconstitution of the cell wall was retarded under both space conditions and simulated weightlessness. The peroxidase activity in protoplasts exposed to microgravity was slightly decreased in both 0 g and 1 g flight samples compared with the ground controls, whereas activity in the protoplasts exposed to simulated weightlessness was similar to activity in the 1 g control. The observation that protoplasts had randomized and more sparse corticular microtubules when exposed to various forms of simulated and real weightlessness on a free-fall machine on the ground could indicate that the low division capacity in 0 g protoplasts was correlated with an abnormal CMT array in these protoplasts. This study has increased our knowledge of the more basic biochemical and cell biological aspects of g effects. This is an important link in preparation for the new space era, when it will be possible to follow the growth of single cells and tissue cultures for generations under microgravity conditions on the new International Space Station, which will be functional on a permanent basis from the year 2003.
Subject(s)
Brassica napus/cytology , Protoplasts/cytology , Space Flight , Weightlessness Simulation , Weightlessness , Brassica napus/physiology , Brassica napus/ultrastructure , Cell Division/physiology , Cell Wall/enzymology , Cell Wall/metabolism , Cell Wall/physiology , Cellulose/metabolism , Centrifugation , Gravitation , Microtubules/physiology , Peroxidase/metabolism , Polysaccharides/metabolism , Protoplasts/physiology , Protoplasts/ultrastructure , RotationABSTRACT
Enzymatic digestion of the cell wall of Brassica napus hypocotyls gave a heterogeneous suspension of protoplasts with the cortical microtubules (CMTs) randomly organised or CMTs organised in parallel. The effect of variable g-influences has been tested on CMT organisation. In contrast to the 1 g-protoplasts, which reorganised the CMTs into parallel arrays during the 96 h test period, the frequency of randomly-oriented CMTs in the protoplasts exposed to simulated weightlessness (0 g) on a 2-D clinostat increased significantly during the same period. The opposite effect was obtained when the protoplasts were exposed to hyper-g (7 or 10 g), where the reorganisation of the CMTs into parallel arrays was accelerated compared to the 1 and 0 g-protoplasts. These results indicate that a unidirectional gravity force is a necessity for the reorganisation of CMTs in protoplasts to parallel arrays and that CMTs act as responding elements that are able to sense different levels of gravity. Besides the inability of the protoplasts to reorganise the CMTs into parallel arrays, the quantity of CMTs in the individual protoplast decreased during 4 days of simulated weightlessness, both compared to the CMTs quantity in the protoplasts immediately after isolation and compared to the 1 g- and hyper-g-protoplasts after 24 and 48 h of g-exposure. The size of the protoplasts was also affected by the g-exposure. Protoplasts exposed to simulated 0 g increased significantly after 24 and 48 h, whereas the 1 g- and 10 g-protoplasts maintained the same size during the 48 h test period.
Subject(s)
Hypergravity , Hypocotyl/ultrastructure , Microtubules/ultrastructure , Protoplasts/ultrastructure , Weightlessness Simulation , Brassica/cytology , Brassica/physiology , Brassica/ultrastructure , Cell Wall/physiology , Gravitation , Hypocotyl/cytology , Hypocotyl/physiology , Microtubules/physiology , Protoplasts/physiology , Rotation , Time FactorsABSTRACT
Transgenic hairy roots of Brassica napus (cv. Omega) have been developed, using Agrobacterium rhizogenes strain AR 25, for use as a model system in the investigation of physiological and morphological differences between transgenic and normal roots. The basic parameters of growth and normal or altered gravitropical behaviour of hairy roots are for the first time presented in this paper together with an ultrastructural and morphological analysis of the root statocytes. The results obtained also represented the basis for the TRANSF0RM-experiment on the IML-2 mission performed onboard the Space Shuttle Columbia. Typical hairy root traits such as hormone-autonomous growth high growth rate, lateral branching, and changed/absence of gravitropism were detected. The transformed nature of the roots was confirmed by Southern blot analyses. The gravitropical behaviour of apices from hairy root cultures of this clone has been compared with root tips from normal seedlings. While the wild type roots curved progressively with increasing stimulation angles, the transformed roots showed no curvature when stimulated at 45 degrees, 90 degrees or 135 degrees on the ground. The morphology and ultrastructure of the root tip regions were examined by light microscopy and transmission electron microscopy. At the ultrastructural level no major differences could be detected between the roots studied. There was, however, a slight reduction in the starch content of most of the amyloplasts of the transgenic root tips, and the root cap was more V-shaped in the transgenic roots than in the wild type. Preliminary results from the Shuttle experiment TRANSFORM show a random distribution of amyloplasts in the root cells of both transformed and wild type root caps after 14 h on a 1xg centrifuge followed by 37 h in microgravity.
Subject(s)
Agrobacterium tumefaciens/genetics , Gravitropism/genetics , Plant Root Cap/growth & development , Plant Roots/genetics , Space Flight , Weightlessness , Blotting, Southern , Brassica/genetics , Brassica/growth & development , Brassica/microbiology , DNA, Plant , Gravitropism/physiology , Microscopy, Electron , Plant Root Cap/ultrastructure , Plant Roots/growth & development , Plants, Genetically Modified , Plasmids , Plastids/physiology , Starch , Transformation, GeneticABSTRACT
In the TRANSFORM experiment for IML-2 on the Space Shuttle Columbia, normal (wild type = WT) and genetically transformed agravitropic rapeseed roots were tested under microgravity conditions. The aim of the experiment was to determine if the wild-type roots behaved differently (growth, morphology, gravitropical sensitivity) from the transgenic roots. The appearance of the organelles and distribution of statoliths (i.e. amyloplasts with starch grains) in the gravitropic reactive cells (statocytes) under weightlessness was compared for the two types of roots. Attempts have also been made to regenerate new plants from the root material tested in space. Both the WT and the transgenic root types showed the expected increase in length during 36 h of photorecording. Contrary to the results of the ground controls, no significant difference in elongation rates was found between the WT and transgenic roots grown in orbit. However, there are indications that the total growth both in the WT and the transgenic roots was higher in the ground control than for roots in orbit. After a 60 min 1 x g stimulation of the roots on board the Shuttle, no detectable curvatures were obtained in either the transgenic or the WT roots. However, it cannot be excluded that a minute curvature development occurs in the root tips but was not detected due to technical reasons. The ultrastructure was well preserved in both the WT and the transgenic roots, despite the fact that the tissue was kept in the prefixative for over 3 weeks. No marked differences in ultrastructure were observed between the transformed root statocyte cells and the equivalent cells in the wild type. There were no obvious differences in root morphology during the orbital period. Light micrographs and morphometrical analysis indicate that the amyloplasts of both the wild type and transformed root statocytes are randomly distributed over the cells kept under micro-g conditions for 37 h after a 14 h stimulation on the 1 x g centrifuge. The main scientific conclusion from the TRANSFORM experiment is that the difference in growth found in the ground control between the WT and the transgenic root types seems to be eliminated under weightlessness. Explanations for this behaviour cannot be found in the root ultrastructure or in root morphology.
Subject(s)
Brassica/growth & development , Gravitropism/physiology , Plant Roots/growth & development , Plants, Genetically Modified/growth & development , Space Flight/instrumentation , Weightlessness , Brassica/ultrastructure , Microscopy, Electron , Plant Root Cap/ultrastructure , Plant Roots/ultrastructure , Plants, Genetically Modified/ultrastructure , Plastids/physiology , Plastids/ultrastructure , RhizobiumABSTRACT
An experiment to study the growth of garden cress roots in microgravity is described. The experiment, denoted RANDOM, was an ESA Biorack experiment in the IML-2 flight in July 1994. In the absence of gravity, it can be anticipated that the roots would show random growth, changing their direction randomly. The hypothesis that such random growth movements occur according to random walk theory, leads to predictions as to the detailed manner in which deviations increase with time. The experiment was designed to test this random walk hypothesis. The paper concentrates on the technological aspects of studying the roots in microgravity. The development of suitable plant chambers, fitting containers developed by ESA, is described as well as the techniques used to grow the seeds between agar slices. hardware was developed to record photographically root movements between the agar slices. Photos were taken once per hour. Some plant chambers were designed to allow fixation of plant material in space. The practical solutions found using glutaraldehyde for prefixation in the Spacelab, within the restrictions given, are described. The experimental results show that the growth pattern in fact followed the prediction from the random walk approach. The average changes in the growth direction stayed constant and equal to zero during the experiment while the squared angular deviations increased proportional to time. Furthermore, plant material prefixed in orbit was permanently fixed after the flight. Light microscopy and electron microscopy pictures are shown as examples of the results achieved. The long prefixation period meant a drawback for the quality of the fixation process. However, sections suitable for study were achieved. The main goals of the RANDOM experiment were therefore achieved.
Subject(s)
Gravitropism/physiology , Plant Roots/growth & development , Space Flight , Weightlessness , Environment, Controlled , Fixatives/adverse effects , Fixatives/pharmacology , Glutaral/adverse effects , Glutaral/pharmacology , Microscopy, Electron , Photography , Plant Development , Plant Roots/drug effects , Plant Roots/ultrastructure , Plants/drug effects , Plants/ultrastructure , TemperatureABSTRACT
The dynamics of root growth was studied in weightlessness. In the absence of the gravitropic reference direction during weightlessness, root movements could be controlled by spontaneous growth processes, without any corrective growth induced by the gravitropic system. If truly random of nature, the bending behavior should follow so-called 'random walk' mathematics during weightlessness. Predictions from this hypothesis were critically tested. In a Spacelab ESA-experiment, denoted RANDOM and carried out during the IML-2 Shuttle flight in July 1994, the growth of garden cress (Lepidium sativum) roots was followed by time lapse photography at 1-h intervals. The growth pattern was recorded for about 20 h. Root growth was significantly smaller in weightlessness as compared to gravity (control) conditions. It was found that the roots performed spontaneous movements in weightlessness. The average direction of deviation of the plants consistently stayed equal to zero, despite these spontaneous movements. The average squared deviation increased linearly with time as predicted theoretically (but only for 8-10 h). Autocorrelation calculations showed that bendings of the roots, as determined from the 1-h photographs, were uncorrelated after about a 2-h interval. It is concluded that random processes play an important role in root growth. Predictions from a random walk hypothesis as to the growth dynamics could explain parts of the growth patterns recorded. This test of the hypothesis required microgravity conditions as provided for in a space experiment.
Subject(s)
Brassicaceae/growth & development , Gravitropism/physiology , Plant Roots/growth & development , Space Flight , Weightlessness , Models, Biological , Photography , Time FactorsABSTRACT
Preparatory tests to improve methods for detection of cortical microtubules (cMTs) in rapeseed protoplasts for the IML-2 experiment "TRANSFORM" were undertaken. This study is based on the results obtained in the "PROTO" experiment onboard the shuttle Discovery during an 8-day IML-1 flight in 1992. The use of free-floating protoplasts on IML-1 made it technically impossible for the astronauts to remove the glutaraldehyde fixative during the orbital period resulting in high background fluorescence which made it very difficult to detect MTs. In order to avoid this on the IML-2 mission, protoplasts will be immobilized in alginate beads. The effect of variable concentrations and fixation periods for two different fixatives on the preservation of cMTs was tested. Best results were obtained using 3.5% paraformaldehyde (PFA) for 1 hour, but 1% glutaraldehyde (GA) also gave acceptable results. The effect of low temperatures on microtubule depolymerization was also examined as freshly isolated protoplasts have to be kept at 5 degrees C for up to 20 hours pre-launch and before activation of Biorack. Only slight changes in cMT-appearance were observed at 4 degrees C indicating a minor depolymerization compared to the cMTs in non-chilled protoplasts.
Subject(s)
Immunohistochemistry/methods , Microtubules/ultrastructure , Protoplasts/cytology , Space Flight , Tissue Fixation/methods , Weightlessness , Alginates , Brassica/cytology , Brassica/physiology , Cell Culture Techniques/methods , Cells, Cultured , Cold Temperature , Fixatives/chemistry , Formaldehyde/chemistry , Glutaral/chemistry , Hypocotyl/cytology , Hypocotyl/physiology , Hypocotyl/ultrastructure , Microtubules/physiology , Polymers/chemistry , Protoplasts/physiology , Protoplasts/ultrastructureABSTRACT
Preparatory experiments for the IML-1 mission using plant protoplasts, were flown on a 14-day flight on Biokosmos 9 in September 1989. Thirty-six hours before launch of the biosatellite, protoplasts were isolated from hypocotyl cells of rapeseed (Brassica napus) and suspension cultures of carrot (Daucus carota). Ultrastructural and fluorescence analysis of cell aggregates from these protoplasts, cultured under microgravity conditions, have been performed. In the flight samples as well as in the ground controls, a portion of the total number of protoplasts regenerated cell walls. The processes of cell differentiation and proliferation under micro-g did not differ significantly from those under normal gravity conditions. However, in micro-g differences were observed in the ultrastructure of some organelles such as plastids and mitochondria. There was also an increase in the frequency of the occurrence of folds formed by the plasmalemma together with an increase in the degree of complexity of these folds. In cell cultures developed under micro-g conditions, the calcium content tends to decrease, compared to the ground control. Different aspects of using isolated protoplasts for clarifying the mechanisms of biological effects of microgravity are discussed.
Subject(s)
Brassica/ultrastructure , Daucus carota/ultrastructure , Protoplasts/ultrastructure , Space Flight , Weightlessness , Brassica/cytology , Brassica/physiology , Calcium/analysis , Cell Differentiation/physiology , Cell Division/physiology , Cell Wall/chemistry , Cells, Cultured , Daucus carota/cytology , Daucus carota/physiology , Hypocotyl/cytology , Hypocotyl/physiology , Hypocotyl/ultrastructure , Microscopy, Electron , Mitochondria/ultrastructure , Organelles/ultrastructure , Plastids/ultrastructure , Protoplasts/physiology , USSRABSTRACT
Preparatory experiments for the IML-1 (International Microgravity Laboratory) mission to be flown on the Space Shuttle in January, 1992, were performed on a 14 day flight on Biokosmos 9 (Kosmos 2044) in September 1989. The purpose of the experiment was to study the effect of weightlessness on protoplast regeneration. Problems with late access to the space vehicle meant that the newly isolated protoplasts from hypocotyl cells of rapeseed (Brassica napus L. cv Niklas) and suspension cultures of carrot (Daucus carota L, cv Nobo) had to be stored at 4 degrees C for 36 h prior to the launch of the biosatellite, in order to delay cell wall regeneration until the samples were in orbit. In the flight samples and the ground controls, a portion of the total number of protoplasts regenerated cell walls. The growth of flight rapeseed cells was only 56% compared to the ground control; the respective growth of carrot cells in orbit was 82% of the ground control. Analysis demonstrated that the peroxidase activity and the amount of protein was lower in the flight samples than in the ground controls. The number of different isoenzymes was also decreased in the flight samples. A 54% decrease in the production of cellulose was found in rapeseed, and a 71% decrease in carrot. Hemicellulose production was also decreased in the flight samples compared to the ground controls. Ultrastructural analysis of the cell aggregates from the protoplasts cultured in orbit, demonstrated that hydrolysis and disappearance of reserve starch occurred in the flight cell plastids. The mitochondria were more varied in appearance in the flight samples than in the ground control cells. An increased frequency of the occurrence of folds formed by the plasmalemma together with an increase in the degree of complexity of these folds was also observed. Fluorescence analysis showed a decrease of the calcium content in cell cultures under space flight compared to the ground controls. One general effect of the stay onboard the space vehicle was a retardation of the regeneration processes. Callus cultures obtained from the flight samples grew very slowly compared to callus regenerated from the ground controls, and two years after the Biokosmos 9 flight there appears to be no further growth in the samples exposed to microgravity. Callus cultures from the ground controls, however, continue to grow well. A simulation experiment for IML-l performed in January 1990 at ESTEC (European Space Technology Center), The Netherlands, has resulted in regenerated plants. These observations are discussed and compared to the results obtained on Biokosmos 9.
Subject(s)
Brassica/cytology , Daucus carota/cytology , Isoenzymes/metabolism , Protoplasts/ultrastructure , Space Flight , Weightlessness , Bioreactors , Brassica/metabolism , Brassica/ultrastructure , Calcium/metabolism , Cell Count , Cell Wall/metabolism , Cells, Cultured , Cytoplasm/metabolism , Daucus carota/metabolism , Daucus carota/ultrastructure , Hypocotyl/cytology , Microscopy, Electron , Peroxidases/metabolism , Protoplasts/cytology , Protoplasts/physiologyABSTRACT
The mutant TC 7 of Arabidopsis thaliana (L.) Heynh. has been reported to be starch-free and still exhibit root gravitropism (T. Caspar and B. G. Pickard 1989, Planta 177, 185-197). This is not consistent with the hypothesis that plastid starch has a statolith function in gravity perception. In the present study, initial light microscopy using the same mutant showed apparently starch-free statocytes. However, ultrastructural examination detected residues of amyloplast starch grains in addition to the starch-depleted amyloplasts. Applying a point-counting morphometric method, the starch grains in the individual amyloplasts in the mutant were generally found to occupy more than 20% and in a few cases up to 60% of the amyloplast area. In the wild type (WT) the starch occupied on average 98% of the amyloplast area and appeared as densely packed grains. The amyloplasts occupied 13.9% of the area of the statocyte in the mutant and 23.3% of the statocyte area in the WT. Sedimentation of starch-depleted amyloplasts in the mutant was not detected after 40 min of inversion while in the WT the amyloplasts sedimented at a speed of 6 micrometers h-1. The gravitropic reactivity and the curvature pattern were also examined in the WT and the mutant. The time-courses of root curvature in the WT and the mutant showed that when cultivated under standard conditions for 60 h in darkness, the curvatures were 83 degrees and 44 degrees, respectively, after 25 h of continuous stimulation in the horizontal position. The WT roots curved significantly more rapidly and with a more normal gravitropic pattern than those of the mutant. These results are discussed in relation to the results previously obtained with the mutant and with respect to the starch-statolith hypothesis.
Subject(s)
Arabidopsis/genetics , Arabidopsis/physiology , Gravitropism/physiology , Plant Root Cap/ultrastructure , Plastids/physiology , Starch/deficiency , Arabidopsis/metabolism , Arabidopsis/ultrastructure , Endoplasmic Reticulum/physiology , Endoplasmic Reticulum/ultrastructure , Gravitation , Gravitropism/genetics , Gravity Sensing/physiology , Microscopy, Electron , Mutation , Plant Root Cap/genetics , Plant Root Cap/metabolism , Plant Root Cap/physiology , Plant Roots/growth & development , Plant Roots/metabolism , Plant Roots/physiology , Plant Roots/ultrastructure , Plastids/ultrastructure , Starch/physiologyABSTRACT
The cytological and intracellular localization of myrosinase (EC 3.2.3.1) has been studied by immunochemical techniques using paraffin-embedded sections of radicles and cotyledons from seeds of Brassica napus L. cv. Niklas. For immunolabelling, sections were sequentially incubated with a monoclonal anti-myrosinase antibody and with peroxidase-and fluorescein-isothiocyanate-conjugated secondary antibodies. Enzyme and fluorescence label was present in typical myrosin cells both in radicles and in cotyledons. With higher magnification, fluorescence label revealed that the intracellular localization of myrosinase was associated with the tonoplast-like membrane surrounding the myrosin grains in the myrosin cells. The results also indicate that a large proportion of the positive myrosin cells are located in the second-outermost cell layer of the peripheral cortex region of the radicles.
ABSTRACT
An experiment using plant protoplasts has been accepted for the IML-1 mission to be flown on a space shuttle in 1991. Preparatory experiments include studies of cell wall formation, cell division, the effect of simulated weightlessness using fast and slow rotating clinostats, and the development and testing of hardware for the IML-1 mission. After 24 h at 25 degrees C, protoplasts isolated from hypocotyls or leaves of rapeseed seedlings, or from carrot suspension cells, show 60, 20 and 15% cell wall formation, respectively. The time course of formation of the cell wall and cell division could be delayed by treatment at low temperatures or immobilization in alginate or agarose. This aspect is of importance in connection with problems of late access to the space shuttle before launch. At 4 degrees C only 18% of the rapeseed hypocotyl protoplasts had formed cell walls after 24 h. Protoplasts immobilised in agarose or alginate gradually regain their cell division capacity and after 72 h the frequencies are 51 and 26%, respectively, compared to non-immobilised control protoplasts. A significant decrease in cell division activity is observed after rotation for 6 h on the slow clinostat. A similar effect is not observed on the fast clinostat. Protoplasts, cultured in the specially designed plant chamber for up to 14 days established cell aggregates which have further developed into plants.
Subject(s)
Brassica/cytology , Daucus carota/cytology , Protoplasts/cytology , Rotation , Space Flight/instrumentation , Weightlessness Simulation , Alginates/pharmacology , Brassica/growth & development , Brassica/ultrastructure , Cell Division/drug effects , Cell Division/physiology , Cell Wall/physiology , Cells, Cultured , Culture Media , Daucus carota/growth & development , Daucus carota/ultrastructure , Evaluation Studies as Topic , Glucuronic Acid , Gravitation , Hexuronic Acids , Hypocotyl/cytology , Plant Leaves/cytology , Sepharose/pharmacology , TemperatureABSTRACT
A follow-up of 92 patients with diabetes mellitus, who were hospitalized at the Department of Pediatrics, University of Bergen, during the years 1950-63, was conducted in June 1986. The mean age of the 76 living patients was 38 years, and the mean duration of diabetes 30 years. Sixteen patients had died. According to the death certificates the causes of death were as follows: Myocardial infarction, uremia, pneumonia, diabetes not further specified, suicide, sudden death not further specified, ketoacidosis, accident to the head, and convulsions (epilepsy). The 39 patients living in the county of Hordaland (including Bergen) were invited to a clinical examination. Twenty-nine patients (mean age 37 years, mean duration of diabetes 29 years) accepted. In eleven, the disease had influenced the choice of occupation. Twelve experienced professional difficulties due to diabetes, and thirteen had major complaints due to the disease. Three used antianginal drugs, and a further three were receiving antihypertensive treatment. Four women had hypothyreosis. Twelve had proteinuria or pathologic microalbuminuria. Only two of 27 patients examined by means of fluorescein-angiography showed no retinopathy. Evidence of cardiovascular autonomic neuropathy was observed in ten patients. Since only three patients had used fast-acting insulin regularly during the last ten years, it should be possible to give patients with type 1 diabetes better treatment in the future.
Subject(s)
Diabetes Mellitus, Type 1/mortality , Adolescent , Adult , Child , Diabetes Mellitus, Type 1/complications , Diabetes Mellitus, Type 1/therapy , Female , Follow-Up Studies , Humans , Male , Middle Aged , Norway , PrognosisABSTRACT
A 32-year-old Norwegian woman was admitted to the University department of Ophthalmology with marked subretinal oedema in both eyes and slight flare in the anterior chambers. Vision was reduced to counting fingers at 1 m o.d. and 6/24 o.s. Lumbal puncture revealed pleocytosis, and antimyelin antibodies were found in the serum confirming and strengthening the clinical diagnosis of Vogt-Koyanagi-Harada syndrome. The patient had a history of colitis ulcerosa 7 years prior to onset of ocular disease. The concurrence of these two diseases has not been reported previously. Treatment with corticosteroids was successful.