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1.
Cells of Daucus carota grown in a liquid medium produced large amounts of cyanidin as the only flavonoid aglycon. After inoculation in fresh medium a maximum activity of phenylalanine ammonia lyase (PAL; EC 4.3.1.5) was observed within 24 h. L--aminooxy--phenylpropionic acid (L-AOPP), thought to be a competitive inhibitor of PAL, inhibited cyanidin accumulation up to 80%. In order to study the regulatory role of PAL, the effects of L-AOPP and t-cinnamic acid, the product of the deamination of phenylalanine, were investigated. Cinnamic acid, applied in vivo (10-4 M), was not able to compensate for the inhibition of cyanidin production caused by L-AOPP (10-4 M) in the same sample. Carrot cells treated with L-AOPP exhibited a super-induction of PAL already described for gherkin hypocotyls (Amrhein and Gerhardt 1979). This effect was not influenced by t-cinnamic acid. L-AOPP seems to be a very specific inhibitor since it affected neither growth nor soluble protein content, whereas t-cinnamic acid inhibited both. Investigations on the content of soluble amino acids in L-AOPP-treated cells revealed a specific accumulation of soluble phenylalanine, whereas treatment with t-cinnamic acid led to an increase of amino acids in general, thus indicating that the latter compound has a rather unspecific effect on cellular metabolism. In vitro studies with PAL isolated from Daucus carota revealed that L-AOPP inhibited the enzyme at very low doses (K
I=2.4·10-9), whereas t-cinnamic acid, by comparison, affected the enzyme at high concentrations (K
I=1.8·10-4).Abbreviations PAL
phenylalanine ammonia lyase
- L-AOPP
L--aminooxy--phenylpropionic acid 相似文献
2.
Else Berit Skagen Tor-Henning Inersen 《In vitro cellular & developmental biology. Plant》2000,36(5):312-318
Summary 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. 相似文献
3.
Microgravity does not alter plant stand gas exchange of wheat at moderate light levels and saturating CO<Subscript>2</Subscript> concentration 总被引:2,自引:0,他引:2
Plant stand gas exchange was measured nondestructively in microgravity during the Photosynthesis Experiment Subsystem Testing and Operations experiment conducted onboard the International Space Station. Rates of evapotranspiration and photosynthesis measured in space were compared with ground controls to determine if microgravity directly affects whole-stand gas exchange of Triticum aestivum. During six 21-day experiment cycles, evapotranspiration was determined continuously from water addition rates to the nutrient delivery system, and photosynthesis was determined from the amount of CO2 added to maintain the chamber CO2 concentration setpoint. Plant stand evapotranspiration, net photosynthesis, and water use efficiency were not altered by microgravity. Although leaf area was significantly reduced in microgravity-grown plants compared to ground control plants, leaf area distribution was not affected enough to cause significant differences in the amounts of light absorbed by the flight and ground control plant stands. Microgravity also did not affect the response of evapotranspiration to changes in chamber vapor pressure difference of 12-day-old wheat plant stands. These results suggest that gravity naïve plants grown at moderate light levels (300 mol m–2 s–1) behave the same as ground control plants. This implies that future plant-based regenerative life support systems can be sized using 1 g data because water purification and food production rates operate at nearly the same rates as in 1 g at moderate light levels. However, it remains to be verified whether the present results are reproducible in plants grown under stronger light levels. 相似文献
4.
Summary When Agrobacterium rhizogenes transformed root cultures of Lotus corniculatus were treated with glutathione, isoflavan phytoalexins accumulated in both tissue and culture medium. This accumulation of phytoalexins was preceded by a transient increase in the activity of phenylalanine ammonia lyase (PAL). Elicitation of PAL occurred throughout the growth curve of Lotus hairy roots and in different sectors of transformed root material. 相似文献
5.
Summary Lateral diffusion measurements have been made on lipids and proteins in the plasma membrane of live protoplasts derived from rose (Rosa sp. Paul's Scarlet) suspension-cultured cells. Two different fluorescent lipid probes exhibited markedly different diffusion rates, indicating possible heterogeneity in the lipid domain of the membrane. Membrane proteins were labeled directly with covalently-reactive fluorophores, and factors that might perturb the lateral diffusion of these labeled proteins were investigated. Treatment of the protoplasts with various cytoskeleton-disrupting drugs generally had little effect on protein diffusion, although treatment with oryzalin, a microtubule-disrupting drug, did slightly reduce the mobile fraction of membrane proteins. Elevation of the CaCl2 concentration in the medium from 1 mM to 10 mM significantly reduced the mobile fraction of membrane proteins and also increased the fraction of protoplasts that were able to regenerate cell walls and divide in culture. These results are discussed in relation to reported evidence of lipid domains in the plasma membranes of other cells and protoplasts. The relative importance of lipid domains and membrane-cytoskeleton interaction in governing protein diffusion is considered.Abbreviations D
lateral diffusion coefficient
- RCA
Ricinus communis agglutinin
- BPA
Bauhinia purpurea agglutinin
- DTAF
dichlorotriazinylaminofluorescein
- FTSC
fluorescein-5-thiosemicarbazide
- C18-Fl
5-(N-octadecanoyl)aminofluorescein
- LY-Chol
Lucifer yellow conjugate of cholesterol, i.e., dilithium 4-amino-N-[(-(carbo(5-cho-lesten-3-yl)oxy)hydrazinocarbonyl)amino]-1,8-naphthalimide-3,6-disulfonate
- APM
amiprophosmethyl
- DMSO
dimethylsulfoxide
- FPR
fluorescence photobleaching recovery
- sd
standard deviation
- FRAF
fluorescence redistribution after fusion
- M
mobile fraction 相似文献
6.
S. Monique Nicoll Lindy A. Brigham Fushi Wen Martha C. Hawes 《Plant Cell, Tissue and Organ Culture》1995,42(1):57-66
Root border cell development and expression of reporter genes were evaluated in transgenic pea hairy roots. Successful induction of hairy roots in pea is conditioned by bacterial strain and plant genotype, as well as by developmental and environmental factors. Morphological changes sometimes occur when hairy roots are transferred from infected plants to tissue culture media, but such changes are confined to specific clones. Expression of reporter genes under the control of promoters from bean (Phaseolus vulgaris L.) stress genes encoding phenylalanine ammonia lyase and chalcone synthase were evaluated. Expression patterns vary between hairy roots taken directly from infected plants, and those grown in culture; most hairy roots taken from infected plants exhibit expression throughout all tissues, whereas expression in cultured hairy roots is most often localized to specific tissues. Patterns of expression that occur during different stages of hairy root development are very similar to those observed in transgenic plants expressing the same fusion genes. Border cell separation and release in hairy roots is normal, and expression of glucuronidase in border cells of some transgenic roots resulted in development of bright blue single cells. Cultured hairy roots should provide a very useful model for studying the effect of defined changes in root border cells on microbial associations with roots of this important legume.Abbreviations YEM
yeast extract-mannitol
- GUS
glucuronidase
- PAL
phenylalanine ammonium lyase
- CHS
chalcone syntase 相似文献
7.
The effect of 8 days of microgravity on regeneration of intact plants from protoplasts 总被引:1,自引:0,他引:1
Ole Rasmussen Carolyn A. Baggerud Hilde C. Larssen Kjetl Evjen Tor-Heiming Iversen A. Kylin 《Physiologia plantarum》1994,92(3):404-411
The growth and development of protoplasts of rapeseed (Brassica napus L. cv Line) and carrot (Daucus carota L. cv. Navona) were studied onboard the Space Shuttle‘Discovery’during an 8-day International Microgravity Laboratory [IML-l) mission in January 1992. The Flight experiments were carried out in‘Biorack'. a fully controlled cell biological experimental facility. under microgravity conditions and in a l-g centrifuge. Parallel experiments were performed in a‘Biorack’module on the ground. After retrieval, some samples were subcultured on appropriate media and analysed for callus growth and regeneration to intact plants. The remainder were used for biochemical analysis. Samples fixed on board the Space Shuttle were kept in l% glutaraldehyde fixative at 4°C for 3–7 days for microscopy analysis after retrieval. Protoplasts exposed to microgravity conditions showed a delay in cell wall synthesis. Cells were swollen in appearance and formed cell aggregates with only few cells. Callus were obtained from protoplasts cultured under microgravity (Fogl). on the l-g centrifuge on board the shuttle (Flg), under normal l-g conditions on the ground (G1g) and on a centrifuge on the ground giving 1.4 g (Gl.4g). Regeneration of intact rapeseed plants was obtained from Flg. Glg and G1.4g. However, no plants were regenerated from protoplasts exposed to microgravity (Fog). Biochemical analysis indicated that the microgravity samples (Fog displayed a reduced packed cell volume, an increased concentration of soluble proteins per cell, and a reduced specific activity of peroxidase in the cytoplasm. Morphometric analysis of fixed samples demonstrated that 3-day old protoplasts under microgravity conditions were significantly larger than protoplasts kept on the l-g centrifuge in space. UItrastructural analysis by transmission electron microscopy showed that protoplasts exposed to microgravity conditions for 3 days had larger vacuoles and a slightly reduced starch content compared to Flg cells. Cell aggregates formed under microgravity conditions (Fog) had an average of 2–I cells per aggregate while aggregates formed under Flg had 8–12 cells. 相似文献
8.
Herbivory damage leads to induction of rapid signals and responses in plants such as oxidative burst, accumulation of secondary metabolites and defensive proteins. Response of various defensive enzymes and secondary metabolites in flag leaf samples of six bread wheat varieties against aphid feeding was investigated. Six bread wheat varieties, namely PBW 621 and HD 2967 (timely sown irrigated), PBW 590 and PBW 658 (late sown irrigated), and PBW 644 and PBW 660 (timely sown rainfed) were grown under the aphid infested and uninfested conditions and were sampled at a regular interval to analyze the biochemical changes caused by aphid feeding. A tremendous increase in the overall activity of various enzymes namely superoxide dismutase, glutathione reductase, phenylalanine ammonia lyase and polyphenol oxidase was observed, all of which play an important role in plants defense towards aphid feeding. Each wheat genotype showed an overall difference in their defensive activity towards aphid feeding. However, certain genotypes under different conditions showed significantly less susceptibility towards aphid damage.
Abbreviations: GR: glutathione reductase; HPR: host plant resistance; PAL: phenylalanine ammonia lyase; PPO: poly phenol oxidase; POD: peroxidase; SOD: superoxide dismutase 相似文献
9.
Syringolide elicitors produced by bacteria expressing Pseudomonas syringae pv. glycinea avirulence gene D (avrD) induce hypersensitive cell death (HCD) only in soybean (Glycine max [L.] Merr.) plants carrying the Rpg4 disease resistance gene. Employing a differential display method, we isolated 13 gene fragments induced in cultured cells of a soybean cultivar Harosoy (Rpg4) treated with syringolides. Several genes for isolated fragments were induced by syringolides in an rpg4 cultivar Acme as well as in Harosoy; however, the genes for seven fragments designated as SIH (for syringolide-induced/HCD associated) were induced exclusively or strongly in Harosoy. cDNA clones for SIH genes were obtained from a cDNA library of Harosoy treated with syringolide. Several sequences are homologous to proteins associated with plant defense responses. The SIH genes did not respond to a non-specific -glucan elicitor, which induces phytoalexin accumulation but not HCD, suggesting that the induction of the SIH genes is specific for the syringolide–Harosoy interaction. HCD and the induction of SIH genes by syringolides were independent of H2O2. On the other hand, Ca2+ was required for HCD and the induction of some SIH genes. These results suggest that the induction of SIH genes by syringolides could be activated through the syringolide-specific signaling pathway and the SIH gene products may play an important role(s) in the processes of HCD induced by syringolides.Abbreviations AOS
active oxygen species
- CHS
chalcone synthase
- DPI
diphenylene iodonium
- HCD
hypersensitive cell death
- HR
hypersensitive response
- PAL
phenylalanine ammonia lyase
- SID
syringolide-induced/defense associated
- SIG
syringolide-induced/general
- SIH
for syringolide-induced/HCD associated
- XET
xyloglucan endotransglycosylase 相似文献
10.
The energy-dependent transport of phenylalanine into isolated vacuoles of barley (Hordeum vulgare L.) mesophyll protoplasts has been studied by silicone-layer floatation filtering. The uptake of this aromatic amino acid into the vacuolar compartment is markedly increased by MgATP, showing saturation kinetics; the K
m values were 0.5 mM for MgATP and 1.2 mM for phenylalanine. V
max for phenylalanine transport was estimated to 140 nmol phenylalanine·(mg·Chl)-1·h-1. The transport shows a distinct pH optimum at 7.3 and is markedly inhibited by 40 mM nitrate. Azide (1 mM) and vanadate (400 M) had no or little effect on rates of transport while p-fluorophenylalanine seemed to be an effective inhibitor, indicating a possible competition at an amino-acid carrier. Ionophores such as valinomycin, nigericin or gramicidin were strong inhibitors of phenylalanine transport, indicating that this process is coupled to both the transmembrane pH gradient (pH) and the transmembrane potential ().Abbreviations and symbols BSA
bovine serum albumin
- Chl
chlorophyll
- Hepes
4-(2-hydroxyethyl)-1-piperazineethanesulfonic acid
- pH
transmembrane pH gradient
-
transmembrane potential 相似文献
11.
Summary The conditions for effective isolation of viable protoplasts from Laminaria japonica with an alginase produced by marine bacterium Alteromonas sp. and a commercially available cellulase were investigated. The highest yields of viable protoplasts (7.910.4x106 cells g–1 FW) were obtained with a hypertonic solution containing 50 % seawater, 25 mM MgCl2, 5 mM HEPES buffer system, and 0.5 M mannitol. Protoplasts were not obtained from thalli of L. japonica when an abalone alginase (abalone acetone powder; AAP: Sigma) was used instead of the bacterial alginase. The isolated protoplasts were cultured in an PESI medium at 5 °C. Complete cell wall formation was observed within 7 days, and dividing cells were first observed in a 9-day-old culture. Some protoplasts regenerated into sheet-shaped thalli and rhizoid structures were also observed on some thalli after 30 to 40 days in culture. This is the first report of protoplast regeneration into plantlets of L. japonica Areschoug (Laminariales, Phaeophyceae).Abbreviations FW
Flesh weight
- AAP
Abalone acetone powder
- HEPES
N-2-hydroxy-ethylpiperazine-N-2-ethanesulfonic acid
- Tris
Tris(hyrdoxymethyl)aminomethane
- PESI
Provasoli's enriched seawater with iodine 相似文献
12.
Modification of growth anisotropy and cortical microtubule dynamics in Arabidopsis hypocotyls grown under microgravity conditions in space
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Kouichi Soga Chiaki Yamazaki Motoshi Kamada Naoki Tanigawa Haruo Kasahara Sachiko Yano Kei H. Kojo Natsumaro Kutsuna Takehide Kato Takashi Hashimoto Toshihisa Kotake Kazuyuki Wakabayashi Takayuki Hoson 《Physiologia plantarum》2018,162(1):135-144
We carried out a space experiment, denoted as Aniso Tubule, to examine the effects of microgravity on the growth anisotropy and cortical microtubule dynamics in Arabidopsis hypocotyls, using lines in which microtubules are visualized by labeling tubulin or microtubule‐associated proteins (MAPs) with green fluorescent protein (GFP). In all lines, GFP‐tubulin6 (TUB6)‐, basic proline‐rich protein1 (BPP1)‐GFP‐ and spira1‐like3 (SP1L3)‐GFP‐expressing using a constitutive promoter, and spiral2 (SPR2)‐GFP‐ and GFP‐65 kDa MAP‐1 (MAP65‐1)‐expressing using a native promoter, the length of hypocotyls grown under microgravity conditions in space was longer than that grown at 1 g conditions on the ground. In contrast, the diameter of hypocotyls grown under microgravity conditions was smaller than that of the hypocotyls grown at 1 g. The percentage of cells with transverse microtubules was increased under microgravity conditions, irrespective of the lines. Also, the average angle of the microtubules with respect to the transverse cell axis was decreased in hypocotyls grown under microgravity conditions. When GFP fluorescence was quantified in hypocotyls of GFP‐MAP65‐1 and SPR2‐GFP lines, microgravity increased the levels of MAP65‐1, which appears to be involved in the maintenance of transverse microtubule orientation. However, the levels of SPR2 under microgravity conditions were comparable to those at 1 g. These results suggest that the microgravity‐induced increase in the levels of MAP65‐1 is involved in increase in the transverse microtubules, which may lead to modification of growth anisotropy, thereby developing longer and thinner hypocotyls under microgravity conditions in space. 相似文献
13.
Changes in the content and subcellular localization of ribonuclease isoenzymes were determined in mesophyll protoplasts prepared fromNicotiana tabacum L. cv. Samsun from healthy and potato virus Y (PVY) infected plants. Intact chloroplasts, mitochondria and soluble cytosolic proteins were obtained after protoplast disintegration by means of differential centrifugation. The 1 000g pellet from healthy protoplasts contained 7.3 %, the 15 000g pellet 13.5 % and 15 000g supernatant 82.1 % of the total activity of ribonucleases. The 1 000g pellet from infected protoplasts contained 10.4%, the 15 000g pellet 10.0% and 15 000g supernatant 89.6 % of the total activity of ribonucleases. The activity of these enzymes in infected protoplasts was enhanced in crude homogenate to 137.0 % (P<0.001), in 1 000g pellet to 194.8 % (P<0.001), in 15 000g pellet to 101.3 % (NS), and in 15 000g supernatant to 149.4 % (P<0.001) of that in healthy noninoculated protoplasts. 相似文献
14.
Fungal elicitor preparations and methyl jasmonate enhance rosmarinic acid accumulation in suspension cultures of Coleus blumei 总被引:3,自引:0,他引:3
bstract Suspension cultures of Coleus blumei (Lamiaceae) treated with either an elicitor preparation from the culture medium of the phytopathogenic oomycete Pythium aphanidermatum or with methyl jasmonate enhanced accumulation of rosmarinic acid approximately threefold. The specific activities of phenylalanine
ammonia lyase and rosmarinic acid synthase were also enhanced after addition of the fungal elicitor. The addition of methyl
jasmonate transiently increased activities of phenylalanine ammonia lyase and hydroxyphenylpyruvate reductase, whereas the
activity of rosmarinic acid synthase was not stimulated and the activity of tyrosine aminotransferase was slightly and constantly
enhanced. Methyl jasmonate stimulated rosmarinic acid accumulation not only when added directly to the culture medium, but
also when it could reach the cells only via the gas phase.
Received: 2 April 1997 / Revision received:16 June 1997 / Accepted: 15 September 1997 相似文献
15.
Cells of Capsicum frutescens Mill. cv. annuum, immobilised in reticulate polyurethane foam, produced higher yields of capsaicin, the pungent principle of Chilli pepper fruits, than did freely-suspended cells, when batch-cultured in a medium conducive to culture growth. In the absence of specific precursors to capsaicin, immobilised cells produced between two and three orders of magnitude higher yields than did suspended cells over 5-d or 10-d culture periods (typically up to 4 or 5 mg capsaicin g-1 dry weight l-1 medium compared with up to 30 g g-1l-1, respectively). These results were reflected by an increased rate and extent of incorporation of L-[U-14C]phenylalanine into capsaicin in immobilised as compared with freely-suspended cells, and evidence is presented for an inverse relationship between incorporation of [14C]phenylalanine into protein and capsaicin. The accumulation of capsaicin can be experimentally manipulated and increased by supplementing the medium with precursors of capsaicin such as phenylalanine and isocapric acid and by reducing the growth rate of immobilised cells by omitting growth regulators from the medium. The importance of these observations is discussed.Abbreviations HPLC
high-performance liquid chromatography
- Phe
phenylalanine
- TLC
thin-layer chromatography 相似文献
16.
The induction of phenylalanine ammonia lyase and phaseollin by 9-aminoacridine and other deoxyribonucleic Acid intercalating compounds 总被引:2,自引:2,他引:0
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Bean pod tissue (Phaseolus vulgaris L. var. Top Crop) is induced to produce phaseollin when challenged with various microorganisms. The pods react in the same manner when challenged with 9-aminoacridine. This compound also caused an increase in concentrations of phenylalanine ammonia lyase, an enzyme of the phaseollin synthesizing pathway. Both the synthesis of phenylalanine ammonia lyase and phaseollin are subject to inhibition by actinomycin D, cycloheximide, or 6-methylpurine. The results suggest that both phaseollin production and increased phenylalanine ammonia lyase, when induced by 9-aminoacridine, require newly synthesized RNA and protein. 相似文献
17.
Plasma-membrane dynamics in live protoplasts from maize (Zea mays L.) roots were characterized and examined for relationships as to the ability of the protoplasts to synthesize new cell walls and develop to cells capable of division. The lateral diffusion-coefficients and mobile fractions of fluorescence-labeled plasma-membrane proteins and lipids were measured by fluorescence photobleaching recovery. Small but significant effects on the diffusion of membrane proteins were observed after treatments with oryzalin or amiprophosmethyl, microtubule-disrupting drugs that increased the mobile fraction, and after treatments with cytochalasins B or D, microfilament-disrupting drugs that decreased the diffusion coefficient. A number of parameters were tested for correlative effects on membrane dynamics and protoplast performance in culture. Protoplasts isolated with a cellulase preparation from Trichoderma viride showed faster membrane-protein diffusion and a lower frequency of development to cells capable of division than did protoplasts isolated with a cellulase preparation from T. reesei. Membrane proteins in maize A632, a line less capable of plant regeneration from callus, diffused with a smaller diffusion coefficient but a greater mobile fraction than did membrane proteins in maize A634, a line with greater regeneration capacity. The plasma membranes of A632 and A634 protoplasts also differed with regard to lateral-diffusion characteristics of phospholipid and sterol probes, although the presence of both rapidly and slowly diffusing lipid components indicated the apparent existence of lipid domains in both A632 and A634. The protoplasts of the two lines did not differ significantly, however, in either wall regeneration or frequency of development to cells capable of division.Abbreviations and symbols D
lateral diffusion coefficient
- FITC
fluorescein-5-isothiocyanate
- FPR
fluorescence photobleaching recovery
- LY
Lucifer yellow
- LY-Chol
dilithium 4-amino-N-[(-(carbo(5-cholesten-3-yl)oxy)hydrazinocarbonyl)aminol]-1,8-naphthalimide-3,6-disulfonate
- LY-DC16:0PE
dilithium 4-amino-N-[3-(-(dipalmitoyl-sn-glycero-3-phosphoethanol-amino)ethylsulfonyl)phenyl]-1,8-naphthalimide-3,6-disulfonate 相似文献
18.
Microgravity and hypergravity effects on collagen biosynthesis of human dermal fibroblasts 总被引:2,自引:0,他引:2
Ulrike Seitzer Michael Bodo Peter K. Müller Yahya Açil Boris Bätge 《Cell and tissue research》1995,282(3):513-517
Astronauts experiencing long periods of space flight suffer from severe loss of bone tissue, particularly in those bones that carry the body weight under normal gravity. It is assumed that the lack of mechanical load decreases connective tissue biosynthesis in bone-forming cells. To test this assumption, quantitative and qualitative aspects of collagen synthesis under microgravity, normal gravity, and hypergravity conditions were investigated by incubating human fibroblast cultures with [3H]-proline for 4, 7, 10, and 20 h during the Spacelab D2-mission in 1993. Quantitative analysis revealed an increase of collagen synthesis under microgravity conditions, being up to 143% higher than in 1 g controls. In contrast, hypergravity samples showed a decrease in collagen synthesis with increasing g, being at the 13% level at 10 g. The relative proportion of collagen in total synthesized protein showed a slight decrease with increasing g. The secretion of collagen by the cells, proline hydroxylation of individual collagen -chains, and the relative proportions of synthesized collagens I, III, and V were not affected under any of the applied conditions.Our research was supported financially by Dara GmbH Bonn (grant. no. 01QV 8866), the Deutsche Forschungsgemeinschaft (SFB A1/367) and BMFT grant. no. 01 KM 9303/8. 相似文献
19.
Tyrosine and Phenylalanine Ammonia Lyase Activities during Shoot Initiation in Tobacco Callus Cultures 总被引:3,自引:0,他引:3
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Both phenylalanine ammonia lyase and tyrosine ammonia lyase were detected in tobacco (Nicotiana tabacum L. Wisconsin 38) callus. The enzymes were separated from each other by Sephadex G-200 column chromatography. Increased activity of tyrosine ammonia lyase was observed during culture of tobacco callus under shoot-forming conditions, while activity of phenylalanine ammonia lyase increased during culture under non-organ-forming conditions. Confirmation of these findings was obtained by examining the incorporation of [14C]tyrosine and [14C]phenylalanine into p-coumarate and trans-cinnamate, respectively. 相似文献
20.
Oriented movement of statoliths studied in a reduced gravitational field during parabolic flights of rockets 总被引:3,自引:0,他引:3
During five rocket flights (TEXUS 18, 19, 21, 23 and 25), experiments were performed to investigate the behaviour of statoliths in rhizoids of the green alga Chara globularia Thuill. and in statocytes of cress (Lepidium sativum L.) roots, when the gravitational field changed to approx. 10–4 · g (i.e. microgravity) during the parabolic flight (lasting for 301–390 s) of the rockets. The position of statoliths was only slightly influenced by the conditions during launch, e.g. vibration, acceleration and rotation of the rocket. Within approx. 6 min of microgravity conditions the shape of the statolith complex in the rhizoids changed from a transversely oriented lens into a longitudinally oriented spindle. The center of the statolith complex moved approx. 14 m and 3.6 m in rhizoids and root statocytes, respectively, in the opposite direction to the originally acting gravity vector. The kinetics of statolith displacement in rhizoids demonstrate that the velocity was nearly constant under microgravity whereas it decreased remarkably after inversion of rhizoids on Earth. It can be concluded that on Earth the position of statoliths in both rhizoids and root statocytes depends on the balance of two forces, i.e. the gravitational force and the counteracting force mediated by microfilaments.Abbreviations ER
endoplasmic reticulum
-
g
9.806 m · s–2
- MF
microfilament
- TEXUS
Technologische Experimente unter Schwerelosigkeit (technological experiments under reduced gravity)
Dedicated to Professor Wolfgang Haupt on the occasion of his 70th birthday 相似文献