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1.
M. A. Ferrer M. A. Pedreño R. Muñoz A. Ros Barceló 《Journal of Plant Growth Regulation》1991,10(1-4):139-146
The distribution of basic soluble isoperoxidases along the growth gradient of lupin hypocotyl was studied in order to establish the role of these isoenzymes in controlling polarly transported indole-3yl-acetic acid (IAA) levels. The observation that the levels of basic isoperoxidases, which diminish from the young (vascular differentiating) to the older (vascular differentiated) tissues, are related with previously reported IAA oxidation rates in decapitated plants, suggests that these isoenzymes can play a role in the oxidation of IAA during polar transport. The fact that the level of basic isoperoxidases is controlled by IAA in hypocotyl sections harvested from different growth zones is in accordance with the previously described adaptative activation of basic isoperoxidases to IAA content. This adaptative activation of basic isoperoxidases might constitute the basic characteristic of a system of subcellular oscillators, coupled at the cellular level, necessary to generate the supracellular auxinwave associated with auxin transport. 相似文献
2.
M. A. Ferrer M. A. Pedreño R. Muñoz A. Ros Barceló 《Journal of Plant Growth Regulation》1991,10(1):139-146
The distribution of basic soluble isoperoxidases along the growth gradient of lupin hypocotyl was studied in order to establish the role of these isoenzymes in controlling polarly transported indole-3yl-acetic acid (IAA) levels. The observation that the levels of basic isoperoxidases, which diminish from the young (vascular differentiating) to the older (vascular differentiated) tissues, are related with previously reported IAA oxidation rates in decapitated plants, suggests that these isoenzymes can play a role in the oxidation of IAA during polar transport. The fact that the level of basic isoperoxidases is controlled by IAA in hypocotyl sections harvested from different growth zones is in accordance with the previously described adaptative activation of basic isoperoxidases to IAA content. This adaptative activation of basic isoperoxidases might constitute the basic characteristic of a system of subcellular oscillators, coupled at the cellular level, necessary to generate the supracellular auxinwave associated with auxin transport. 相似文献
3.
Indole-3-methanol is the main product of the oxidation of indole-3-acetic acid catalyzed by two cytosolic basic isoperoxidases from Lupinus 总被引:1,自引:0,他引:1
The nature of the products of the auxin catabolism mediated by both basic and acidic isoperoxidases has been studied. While indole-3-methanol is only a minor product of the oxidation of indole-3-acetic acid catalyzed by extracellular acidic isoperoxidases, it is the only product of the oxidation of indole-3-acetic acid catalyzed by two cytosolic basic isoperoxidases (EC 1.11.1.7) from lupin (Lupinus albus L.) hypocotyls. The putative indole-3-methanol formed by these latter isoperoxidases was isolated and then characterized by mass spectrometry and 1H-nuclear magnetic resonance spectrometry. These results are discussed with respect to the diversity and compartmentation of the catabolism of indole-3-acetic acid in plant tissues.Abbreviations DCP
2,4-dichlorophenol
- IAA
indole-3-acetic acid
- IM
indole-3-methanol 相似文献
4.
Indole-3-Acetic Acid Control on Acidic Oat Cell Wall Peroxidases 总被引:2,自引:0,他引:2
Incubation of oat coleoptile segments with 40 μm indoleacetic acid (IAA) induced a decrease of 35–60% in peroxidase activity at the cell wall compartment. Treatment with
IAA also produced a similar decrease in the oxidation of NADH and IAA at the cell wall. Isoelectric focusing of ionic, covalent,
and intercellular wall peroxidase fractions showed that acidic isoforms (pI 4.0–5.5) were reduced preferentially by IAA treatment.
Marked differences were found between acidic and basic wall isoperoxidases in relation to their efficacy in the oxidation
of IAA. A peroxidase fraction containing acidic isoforms oxidized IAA with a V
max/s0.5 value of 2.4 × 10−2 min−1· g fw−1, 4.0 times higher than that obtained for basic peroxidase isoforms (0.6 × 10−2 min−1· g fw−1). In contrast, basic isoforms were more efficient than acidic isoperoxidases in the oxidation of coniferyl alcohol or ferulic
acid with H2O2 (5.6 and 2.1 times, respectively). The levels of diferulate and lignin in the walls of oat coleoptile segments were not altered
by treatment with IAA. The decrease in cell wall peroxidase activity by IAA was related more to reduced oxidative degradation
of the hormone than to covalent cell wall cross-linking.
Received November 1, 1998; accepted December 14, 1998 相似文献
5.
Synchronization of somatic embryogenesis at high frequency is a useful system for the mass production of embryos. Many attempts have been carried out, however, it was difficult to obtain the system in which most of the initial embryogenic cells or cell clusters synchronously differentiate to embryos. In carrot suspension cultures, high frequency, synchronous embryogenesis systems (following three systems) have been established.(1) Small spherical single cells from suspension cultures obtained by sieving and density gradient centrifugation in Percoll solutions differentiated to embryogenic cell clusters at high frequency when they were cultured in a medium containing 2,4-dichlorophenoxyacetic acid (0.05 micromolar), zeatin (1 micromolar) and mannitol (0.2 molar). (2) Embryogenic cell clusters from suspension cultures obtained by sieving, density gradient centrifugation in Ficoll solutions, and subsequent centrifugation at a low speed for a short time synchronously differentiated to embryos, especially globular embryos at high frequency, when they were cultured in a medium containing zeatin (0.1 micromolar) but no auxin. (3) Embryogenic cell clusters obtained by above method are cultured at cell densities of 2×103 cell clusters ml-1. Globular embryos which were sieved from embryos induced synchronously differentiated to torpedo-shaped embryos at high frequency when they were cultured at densities below 150 globular embryos ml-1.Using these systems, the whole process of embryogenesis from single cells to whole plants could be synchronously induced at high frequency.Abbreviations ABA
abscissic acid
- 2,4-d
2,4-dichlorophenoxyacetic acid
- GA3
gibberellin A3
- IAA
indoleacetic acid
- NAA
naphthylacetic acid 相似文献
6.
Synthesis of indole-3-acetic acid (IAA), using stable-isotope incorporation, was investigated in Zea mays L. Incorporation of 2H from 2H2O into IAA molecules was shown to occur in intact plantlets and excised primary roots cultured in vitro. This demonstrates the de-novo formation of IAA, a process which is quantitatively well defined and is initiated early in germination.Abbreviations IAA
indole-3-acetic acid 相似文献
7.
The study of ammonium (NH4
+) transport across plant cell membranes requires accurate measurement of NH4
+ gradients across subcellular gradients. We have developed an ammonium-selective microelectrode based on the ionophore nonactin.
This electrode can detect NH4
+ activities (aNH4) in vivo in the millimolar range in the presence of cytosolic levels of potassium, the main interfering ion. The electrode was used
to measure intracellular aNH4 in internodal cells of the giant alga Chara corallina. Results from cells incubated in media supplemented with 1 mM NH4
+ produced two populations, with means of 7.3 and 30.8 mM, respectively. HPLC analysis of vacuolar sap suggests the higher population represents vacuolar impalements, and the lower
population can thus be assumed to be cytosolic. These results suggest a four-fold accumulation of NH4
+ in the vacuolar compartment of Chara.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
8.
9.
T.T. Lee 《Phytochemistry》1974,13(11):2445-2453
IAA oxidase and peroxidase were found in all subcellular fractions of tobacco callus cells. The bound and cytoplasmic fractions differed greatly in IAA oxidase/peroxidase ratio and in isoperoxidase composition. The IAA oxidase/peroxidase ratio was particularly high in the plasma membrane-rich fraction. Kinetin had profound effects on IAA oxidase and peroxidase. The appearance of fast migrating isoperoxidases in response to 0·2 μM kinetin was found only in cytoplasmic, plasma membrane and ribosome-rich fractions; a high concentration of kinetin inhibited their formation. High kinetin concentrations also lowered the specific activity of IAA oxidase and peroxidase in all subcellular fractions, but the effect was much greater on peroxidase than on IAA oxidase, thus resulting in a drastic increase in IAA oxidase/peroxidase ratio. Evidently the activities of IAA oxidase and peroxidase were not equivalent and should be considered separately. 相似文献
10.
2,4-Dichlorophenoxyacetic acid (2,4-D) promotes the accumulation of tryptophan-derived indole-3-acetic acid (IAA) in carrot cell cultures during callus proliferation by a biosynthetic pathway that is apparently not active during somatic embryo formation. The effects of 2,4-D were examined by measuring the isotopic enrichment of IAA due to the incorporation of stable isotope-labeled precursors (deuterium oxide, [15N]indole, and 2H5-l-tryptophan). Enrichment of IAA from deuterium oxide is similar in both cultured hypocotyls and cell suspension cultures in the presence and absence of 2,4-D, despite the large differences in absolute IAA concentrations. The enrichment of IAA due to the incorporation of [15N]indole is also similar in callus proliferating in the presence of 2,4-D and in embryos developing in the absence of 2,4-D. The incorporation of 2H5-l-tryptophan into IAA, however, is at least 7-fold higher in carrot callus cultures proliferating in the presence of 2,4-D than in embryos developing in the absence of 2,4-D. Other experiments demonstrated that this differential incorporation of 2H5-l-tryptophan into IAA does not result from differential tryptophan uptake or its subsequent compartmentation. Thus, it appears that differential pathways for IAA synthesis operate in callus cultures and in developing embryos, which may suggest that a relationship exists between the route of IAA biosynthesis and development. 相似文献
11.
Summary Elicitors of the ectomycorrhizal fungus Hebeloma crustuliniforme and auxins (IAA, NAA and 2,4-D) were tested for their effects on apoplastic proteins and enzymes of suspension cultured cells of Picea abies (L.) Karst. The ectomycorrhizal elicitor increased the amount of some ionically wall-bound proteins (36, 28, 24, 21 kDa) and decreased the amount of others (61, 22 kDa). The elicitor triggered an H2O2 burst and enhanced the peroxidase (EC 1.11.1.7) activity of the Picea cells by increasing one of the two wall-bound peroxidase isoforms. Auxins significantly suppressed the elicitor induction of peroxidase but did not influence the elicitor-triggered H2O2 burst. The elicitors and auxin did not change the amount and the pattern of wall-bound invertase isoforms (EC 3.2.1.26) of spruce cells. However, auxin reduced the uptake of glucose by spruce cells and increased the acidification of the cell culture medium. Since Hebeloma lacks apoplastic invertase as well as a sucrose uptake system, utilization of plant-derived sucrose depends on the apoplastic plant invertase activity. Although the host invertase is constitutive, the fungus might be able to increase this invertase activity within a mycorrhiza by lowering the pH of the interface towards the pH optimum of the enzyme via the action of auxin. This fungus-released hormone could increase the H+ extrusion of plant cells by activation of the plant membrane H+-ATPases. Additionally, an auxin-dependent suppression of glucose uptake by cortical root cells could improve the glucose supply for the fungus. Furthermore, the fungal auxin might suppress the elicitor induced formation of defense enzymes, such as peroxidase. 相似文献
12.
Eight isoperoxidases from tobacco suspension culture WR-132 (termed Cn, C3, C4, Ac, and Af) and tobacco callus culture W-38 (termed A1, A2, and A3) have been subjected to trypsin digestion followed by peptide mapping. The peptide maps of isoperoxidases Af and A3 are identical. All other isoperoxidases do not appear to be dramatically dissimilar in certain portions of their sequence, since many matching peptides have been found when various isoperoxidases are cross-compared. However, only two, and possibly three, highly homologous peptides are present in all of the isoperoxidases. 相似文献
13.
Summary The establishment of suspension cell cultures from trimmed cotyledons of pepper (Capsicum annuum L.) provides a new experimental system for studying the relationship between release of peroxidase (EC 1.11.1.7) into the free intercellular spaces and plant cell growth. In contrast with several other species, the total peroxidase activity in the medium increased continuously during the post-exponential growth phase of the pepper cell culture, and this was correlated with the growth inhibition of pepper cells cultivated in suspension. The increase in the peroxidase activity in the culture medium was the consequence of a differential release of isoperoxidases, prominently marked by a primary release of basic isoperoxidases, followed by a strong increase in the level of acidic isoperoxidases. Thus, pepper cells cultures constitute a new experimental system for studying the regulation of the sequential release of basic and acidic isoperoxidases, which occurs during the growth cessation of plant cells. 相似文献
14.
Bernard L. Powell Jerry W. Pickering Simon H. Wender Eddie C. Smith 《Phytochemistry》1975,14(8):1715-1717
Two anodic isoperoxidases (A1 and A2) from tobacco tissue culture W-38 and two cathodic isoperoxidases (C3 and C4) from tobacco suspension culture WR-132 have been separated and characterized. Molecular weights for each of the isoperoxidases have been determined by two different methods. Only C4 contained a carbohydrate component. The substrate specificity and the pH optima for the four enzymes with each of five substrates were determined. 相似文献
15.
Acidic inorganic phosphate (Pi) pool (pH around 6) was detected besides the cytoplasmic pool in intact cells of Chlorella vulgaris 11h by 31P-in vivo nuclear magnetic resonance (NMR) spectroscopy. It was characterized as acidic compartments (vacuoles) in combination with the cytochemical technique; staining the cells with neutral red and chloroquine which are known as basic reagents specifically accumulated in acidic compartments. Under various conditions, the results obtained with the cytochemical methods were well correlated with those obtained from in vivo NMR spectra; the vacuoles were well developed in the cells at the stationary growth phase where the acidic Pi signal was detected. In contrast, cells at the logarithmic phase in which no acidic Pi signal was detected contained only smaller vesicles that accumulated these basic reagents. No acidic compartment was detected by both cytochemical technique and 31P-NMR spectroscopy when the cells were treated with NH4OH. The vacuolar pH was lowered by the anaerobic treatment of the cells in the presence of glucose, while it was not affected by the external pH during the preincubation ranging from 3 to 10. Possible vacuolar functions in unicellular algae especially with respect to intracellular pH regulation are discussed.Non-standard abbreviations EDTA
ethylenediaminetetraacetic acid
- HEPES
N-2-hydroxyethylpiperazine-N-2-ethanesulfonic acid
- MDP
methylene diphosphonic acid
- NMR
nuelear magnetic resonance
- PCA
perchloric acid
- PCV
packed cell volume
- Pi
inorganic phosphate
- Pic
sytoplasmic inorganic phosphate
- Piv
vacuolar inorganic phosphate
- ppm
parts per million
- SP
sugar phosphates
- TCA
trichloroacetic acid 相似文献
16.
Peter Lundberg Hans J. Vogel Peter E. Brodelius 《In vitro cellular & developmental biology. Plant》1997,33(4):301-305
Summary The induction of metabolic changes in suspension cultured cells of Catharanthus roseus upon elicitation has been investigated. Addition of a yeast glucan preparation to the growth medium resulted in induction
of phenylalanine ammonia lyase. Phosphate uptake and metabolism of elicited cells was followed by 31P nuclear magnetic resonance. The uptake rate of Pi from the medium by oxygenated cells of C. roseus was reduced immediately after elicitation. Despite this reduced Pi uptake elicited cells had significantly increased amounts
of ATP (twofold increase within 6 h). Cytoplasmic levels of Pi, phosphomonoesters, and Uridine Diphasphate glucose (UDP-Glc)
were unaffected by eliciation. Furthermore, the cytoplasmic and vacuolar pH remained constant after addition of elicitor. 相似文献
17.
Mass fragmentography employing a deuterated internal standard was used to make quantitative analyses of indole-3-acetic acid in xylem sap collected from Ricinus communis L. When contamination of the sap by microorganisms was reduced by frequent collection, levels of IAA were found to be less than 0.5 ng ml-1. It is therefore proposed that the transpiration stream does not play a significant role in the transport of IAA within the plant.Abbreviations IAA
indole-3-acetic acid
- GC-MS
gas chromatography-mass spectrometry
- BSTFA
bis-Trimethylsilytrifluoroacetamide
- TMCS
trimethylchlorosilane
- BSA
bis-Trimethylsilylacetamide
- TMS2-IAA
bis-trimethylsilyl derivative of IAA 相似文献
18.
Wolfgang Pfeiffer 《Trees - Structure and Function》1998,13(2):112-116
Vacuolar ATPase (EC 3.6.1.3) and PPase (EC 3.6.1.1) were studied in suspension cells and seedlings from spruce [Picea abies (L.) Karst. Proton transport activity and uncoupler (1 μM nigericin) stimulated substrate hydrolysis were measured in tonoplast
enriched membrane vesicles. In suspension cells the vacuolar PPase exhibited 1.8-fold activity of the ATPase. In roots and
needles from 12-week-old spruce seedlings the vacuolar PPase was inactive, whereas the ATPase was active. Therefore, we investigated
whether the preparation of spruce tonoplast vesicles from roots and needles inactivates the vacuolar PPase but not the ATPase.
For this purpose, maize (Zea mays L.) tonoplast membranes exhibiting vacuolar PPase as well as ATPase activity were used as a probe and added to the homogenization
medium prior to the preparation of spruce vesicles. The preparation of spruce vesicles was more inhibitory to the vacuolar
ATPase than to the PPase. The comparison of vacuolar PPases from spruce suspension cells and maize roots revealed similar
enzymatic properties. After isopycnic centrifugation on continuous sucrose gradients the vacuolar PPase from spruce suspension
cells co-purified with the vacuolar ATPase. Together, these data show: (1) vacuolar PPases from spruce suspension cells and
maize roots are similar, (2) the preparation of tonoplast vesicles from spruce roots and needles does not inactivate the vacuolar
PPase, (3) tonoplasts of suspension cultured cells and seedlings from spruce are differentially energized by the vacuolar
pyrophosphatase that may indicate a difference in pyrophosphate metabolism between embryogenic and differentiated spruce cells,
and (4) tonoplast vesicles from spruce seedlings may allow investigations of the effect of pyrophosphate on the vacuolar ATPase
in the absence of vacuolar PPase activity.
Received: 2 July 1998 / Accepted: 14 September 1998 相似文献
19.
Toshiaki Nishida Naoto Ohnishi Hiroaki Kodama Atsushi Komamine 《Plant Cell, Tissue and Organ Culture》1992,28(1):37-43
A system of synchronous cell division was established by starvation of auxin and its readdition to suspension cultures of cells of Catharanthus roseus L. cv. Little-Pinky. When cells in the stationary phase were transferred to fresh medium free of 2,4-dichlorophenoxyacetic acid (2,4-D), cells were arrested preferentially at the G1 phase. After cells had been cultured for 2 days in medium without 2,4-D, readdition of 2,4-D induced the synchronous division of cells. In this system, 70–80% of cells divided synchronously within 3 to 4h, and the mitotic index increased sharply in parallel with the increase in cell number. Active synthesis of DNA was demonstrated by measurements of incorporation of [3H]-thymidine into the DNA fraction. The induction of cell division by the addition of 2,4-D was inhibited by treating cells with analogues of auxin, such as 2,4,6-trichlorophenoxyacetic acid and p-chlorophenoxyisobutyric acid.Abbreviations 2,4-D
2,4-dichlorophenoxyacetic acid
- DAPI
4,6-diamidino-2-phenylindole
- IAA
indole-3-acetic acid
- MS
Murashige & Skoog
- NAA
-naphthalenacetic acid
- PCIB
p-chlorophenoxyisobutyric acid
- 2,4,6-T
2,4,6-trichlorophenoxyacetic acid 相似文献
20.
The signaling lipid phosphatidylinositol‐3,5‐bisphosphate targets plant CLC‐a anion/H+ exchange activity
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Armando Carpaneto Anna Boccaccio Laura Lagostena Eleonora Di Zanni Joachim Scholz‐Starke 《EMBO reports》2017,18(7):1100-1107
Phosphatidylinositol‐3,5‐bisphosphate (PI(3,5)P2) is a low‐abundance signaling lipid associated with endo‐lysosomal and vacuolar membranes in eukaryotic cells. Recent studies on Arabidopsis indicated a critical role of PI(3,5)P2 in vacuolar acidification and morphology during ABA‐induced stomatal closure, but the molecular targets in plant cells remained unknown. By using patch‐clamp recordings on Arabidopsis vacuoles, we show here that PI(3,5)P2 does not affect the activity of vacuolar H+‐pyrophosphatase or vacuolar H+‐ATPase. Instead, PI(3,5)P2 at low nanomolar concentrations inhibited an inwardly rectifying conductance, which appeared upon vacuolar acidification elicited by prolonged H+ pumping activity. We provide evidence that this novel conductance is mediated by chloride channel a (CLC‐a), a member of the anion/H+ exchanger family formerly implicated in stomatal movements in Arabidopsis. H+‐dependent currents were absent in clc‐a knock‐out vacuoles, and canonical CLC‐a‐dependent nitrate/H+ antiport was inhibited by low concentrations of PI(3,5)P2. Finally, using the pH indicator probe BCECF, we show that CLC‐a inhibition contributes to vacuolar acidification. These data provide a mechanistic explanation for the essential role of PI(3,5)P2 and advance our knowledge about the regulation of vacuolar ion transport. 相似文献