Chlorate transport in isolated tonoplast vesicles from red beet (Beta vulgaris L.) storage tissue

Chodera, Amy J.; Briskin, Donald P.

doi:10.1016/0168-9452(90)90238-j

Cited by 10 publications

(4 citation statements)

References 32 publications

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“…Much of the nitrate in plant cells accumulates in the vacuoles (21). Chodera and Briskin (6) have indicated that uptake of chlorate into tonoplast vesicles is mediated by a A'T driven uniport mechanism, and it has been suggested that nitrate flux across the vacuole may regulate cytoplasmic nitrate content and overall flux of nitrate into the plants (7). Others have suggested that uptake is regulated by an inducible nitrate carrier mechanism within the plasma membrane (7).…”

Section: Discussionmentioning

confidence: 99%

Characterization of Tonoplast Polypeptides Isolated from Corn Seedling Roots

Ni¹,

Beevers²

1991

Plant Physiol.

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Tonoplast vesicles were isolated by discontinuous sucrose gradient centrifugation in the presence of Mg2+ from 5 day old corn (Zea mays L., Golden Cross Bantam) seedling roots. Marker enzyme assays indicated only a low degree of cross-contamination of tonoplast vesicles at the 10/23% (weight/weight) interface by other membrane components. Severalfold enrichment of tonoplast ATPase and pyrophosphatase was indicated in tonoplast fractions by dot blot studies with antibodies against an oat tonoplast ATPase and a mung bean tonoplast pyrophosphatase. Comparison of two-dimensional electrophoretic gels of tonoplast and microsomal membrane polypeptides revealed approximately 68 polypeptides to be specific to tonoplast by silver staining. Immunoblot analysis with antibodies against a tonoplast holoenzyme ATPase from oat roots revealed the presence of the 72, 60, and 41 kilodalton polypeptides in isolated tonoplast vesicles from corn roots. Affinity blotting with concanavalin A and secondary antibodies indicated the degree of glycosylation of tonoplast polypeptides, where 21 of 68 tonoplast-specific polypeptides contained detectable carbohydrate moieties. Salt and NaOH washes removed 38 of the tonoplast-specific polypeptides, indicating a peripheral association with the membrane. Thirteen of the peripheral polypeptides and eight of the integral polypeptides were identified as glycoproteins. This information on the polypeptide composition of the tonoplast of root cells will aid in gaining insight into the role of this membrane in controlling vacuolar functions.The central vacuole of mature plant cells usually occupies 80% or more of the intracellular volume. It is now recognized that vacuoles function in osmotic-based tissue support, ion balance and storage, metabolite storage and sequestration, and senescence and lysosomal compartmentation (32). Many of these functions are mediated by the tonoplast membrane, which separates the neutral cytosol from the acidic and hydrolytic vacuolar sap. Since the development of techniques for the routine isolation of vacuoles, much information has been obtained on the properties of the tonoplast and the composition of the vacuolar sap (3). It is recognized that a Mg+-ATPase or pyrophosphatase generates a proton motive force across the tonoplast that can be utilized to energize the transport of various solutes. Evidence for Ca2+/H', Na+/H+, sucrose/H+ antiport, and NO3-/H' symport in the tonoplast has been provided (13). However, apart from the isolation of proton-translocating ATPase and pyrophosphatase, very little is known about tonoplast membrane proteins that conduct the rapid and specific exchange of ions, metabolites, and proteins between the cytosol and vacuolar sap.Characterization of the protein composition of the tonoplast is an important initial step in understanding the mechanism by which the vacuole functions as an active metabolic compartment within the plant cell. Customarily, a particular membrane is identified and contamination assessed by the distribution of a s...

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Section: Discussionmentioning

confidence: 99%

Characterization of Tonoplast Polypeptides Isolated from Corn Seedling Roots

Ni¹,

Beevers²

1991

Plant Physiol.

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“…1982). Chodera and Briskin (1990) showed that CIO:; uptake was ATP-dependent and saturable in sealed tonoplast vesicles from red beet. CIO:; uptake was driven by an inside positive membrane potential, but not by an artificially imposed pH gradient.…”

Section: Uptake A/inorganic Anionsmentioning

confidence: 99%

Transport Processes in Vacuoles of Higher Plants

Martinoia

1992

Botanica Acta

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The vacuole is the largest compartment of a mature plant cell and serves as an internal reservoir of metabolites and nutrients. In the last years transport of solutes across the tonoplast has been intensively investigated. It was shown that two different proton pumps reside in the tonoplast. These pumps generate an electrochemical gradient which can be used as an energy‐source to accumulate solutes. Cation uptake is driven by an H+ antiport mechanism. Anions are accumulated in response to the inside positive membrane potential. In addition, the existence of ion channels was shown using the patch clamp technique. The aim of this review is to compare and to discuss the present state of our knowledge of solute transport across the tonoplast.

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“…This enzyme can utilize the pyrophosphate pro duced from a number of metabolic reactions taking place in the cytoplasm as a chemical energy source for driving transport (33). As at the plasma membrane, the proton electrochemical gradient across the vacuolar membrane is utilized by a number of secon dary transport systems which have been identified including an H + /Na + antiport (3), an H + /Ca 2+ antiport (4), an H + /sucrose antiport (14), an N0 3 -uniport (8), an H + /N0 3 -antiport (27), and ion channels examined using patch clamp (17). There is also some evidence for the presence of an H + -translocating ATPase at the Golgi membrane that may be biochemically similar to the H + -translocating ATPase associated with the vacuolar membrane (42).…”

Section: Transport Of Solutes Across Plant Membranesmentioning

confidence: 99%

Membranes and Transport Systems in Plants: An Overview

Briskin

1994

Weed sci.

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Membranes define the outer boundary of the living protoplast and the internal compartmentation of plant cells. From a structural point of view, membranes consist of a lipid bilayer and proteins essential for functions such as solute transport, signal transduction, and numerous metabolic reactions. While membranes can represent a significant barrier to the free movement of many solutes, those with sufficient lipid solubility may move across membranes by dissolving into the lipid bilayer. However, selective membrane transport is generally observed for hydrophilic solutes such as mineral nutrients and cell metabolites. Such selective transport requires an input of metabolic energy, and in plants this occurs via the production of proton electrochemical gradients across the membrane by substrate- (ex. ATP, PPi) driven proton pumps. Selective solute transport is then mediated by membrane-associated secondary transport systems which utilize the proton electrochemical gradient to drive the transport process. This review of membrane structure and transport system function provides a background for a further examination of herbicide interactions with plant membranes.

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Chlorate transport in isolated tonoplast vesicles from red beet (Beta vulgaris L.) storage tissue

Cited by 10 publications

References 32 publications

Characterization of Tonoplast Polypeptides Isolated from Corn Seedling Roots

Characterization of Tonoplast Polypeptides Isolated from Corn Seedling Roots

Transport Processes in Vacuoles of Higher Plants

Membranes and Transport Systems in Plants: An Overview

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