Sugar transport across the plasma membranes of higher plants

1994 ◽  
pp. 435-443
Author(s):  
Norbert Sauer ◽  
Kerstin Baier ◽  
Manfred Gahrtz ◽  
Ruth Stadler ◽  
Jürgen Stolz ◽  
...  
Keyword(s):  
Plasma Membranes ◽  
Higher Plants ◽  
Sugar Transport

Sugar transport across the plasma membranes of higher plants

1994 ◽  
Vol 26 (5) ◽  
pp. 1671-1679 ◽  
Author(s):  
Norbert Sauer ◽  
Kerstin Baier ◽  
Manfred Gahrtz ◽  
Ruth Stadler ◽  
J�rgen Stolz ◽  
...  
Keyword(s):  
Plasma Membranes ◽  
Higher Plants ◽  
Sugar Transport

Defect in regulation of membrane transport of monosaccharides in dystrophic muscle

1979 ◽  
Vol 57 (7) ◽  
pp. 695-701 ◽  
Author(s):  
J. Elbrink
Keyword(s):  
Plasma Membranes ◽  
Sugar Transport ◽  
Normal Muscle ◽  
Dystrophic Muscle ◽  
Variable Effect ◽  
Cardiomyopathic Hamsters ◽  
Uncoupling Of Oxidative Phosphorylation ◽  
Dystrophic Mice ◽  
Normal Controls ◽  
Glucose Analogue

The penetration of a nonmetabolized glucose analogue, 3-O-methyl-D-glucose, across the plasma membranes of tissues from dystrophic mice and cardiomyopathic (dystrophic) hamsters has been compared with that of normal controls. Under basal conditions the penetration of test sugar was similar in lens and diaphragm of normal and dystrophic 129/ReJ mice. Stimulation of sugar transport by 2,4-dinitrophenol did occur in normal but not in dystrophic diaphragm. A submaximal concentration of insulin had a more variable effect in dystrophic than in normal muscle while a supramaximal concentration of the hormone increased the uptake of the glucose analogue to an equal extent in the two tissues. In the BIO 14.6 strain of cardiomyopathic hamsters, uncoupling of oxidative phosphorylation did not increase sugar transport in extensor digitorum longus muscles, while the normal effect was observed in dystrophic soleus and in both these muscles of the random bred controls. The absence of an effect by a condition simulating anoxia suggests that in dystrophy, certain muscles are unable to accelerate the entry of glucose when this is required.

The regulation of assimilate allocation and transport

2000 ◽  
Vol 27 (6) ◽  
pp. 583 ◽  
Author(s):  
Hanjo Hellmann ◽  
Laurence Barker ◽  
Dietmar Funck ◽  
Wolf B. Frommer
Keyword(s):  
Higher Plants ◽  
Sugar Transport ◽  
Long Distance ◽  
Regulatory Pathways ◽  
Sugar Transporters ◽  
E Coli ◽  
Long Distance Transport ◽  
N Metabolism ◽  
C And N ◽  
And Storage

In higher plants, sugars possess multiplefunctions: transport and storage of carbon and energy as well as signalmolecules. A variety of sugar transporters have been cloned that showdifferential expression between source and sink tissues. Expression of thesetransporters is highly regulated, according to the local metabolic status andthe demands of long distance transport. Very little knowledge is available onmechanisms underlying the regulation of sugar transporter expression inplants. Studies in E. coli, yeast and mammals haveunravelled complex regulatory pathways with crosstalk between sugar transportand metabolism. Recent studies in plants provide increasing evidence for theexistence of similar regulatory mechanisms. In many cases, connections havebeen found between C-and N-metabolism, implicating a tight network of signaltransduction and metabolism. Some aspects of this network are presented inthis review, emphasising sugar transport and sugar signaltransduction.

scholarly journals Transcripts switched off at the stop of phloem unloading highlight the energy efficiency of sugar import in the ripening V. vinifera fruit

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Stefania Savoi ◽  
Laurent Torregrosa ◽  
Charles Romieu
Keyword(s):  
Cell Wall ◽  
Plasma Membranes ◽  
Sugar Transport ◽  
Regulatory Elements ◽  
Solute Concentration ◽  
Growth Patterns ◽  
Individual Growth ◽  
Sugar Accumulation ◽  
Minor Role ◽  
Phloem Unloading

AbstractTranscriptomic changes at the cessation of sugar accumulation in the pericarp of Vitis vinifera were addressed on single berries re-synchronised according to their individual growth patterns. The net rates of water, sugars and K+ accumulation inferred from individual growth and solute concentration confirmed that these inflows stopped simultaneously in the ripe berry, while the small amount of malic acid remaining at this stage was still being oxidised at low rate. Re-synchronised individual berries displayed negligible variations in gene expression among triplicates. RNA-seq studies revealed sharp reprogramming of cell-wall enzymes and structural proteins at the stop of phloem unloading, associated with an 80% repression of multiple sugar transporters and aquaporins on the plasma or tonoplast membranes, with the noticeable exception of H+/sugar symporters, which were rather weakly and constitutively expressed. This was verified in three genotypes placed in contrasted thermo-hydric conditions. The prevalence of SWEET suggests that electrogenic transporters would play a minor role on the plasma membranes of SE/CC complex and the one of the flesh, while sucrose/H+ exchangers dominate on its tonoplast. Cis-regulatory elements present in their promoters allowed to sort these transporters in different groups, also including specific TIPs and PIPs paralogs, and cohorts of cell wall-related genes. Together with simple thermodynamic considerations, these results lead to propose that H+/sugar exchangers at the tonoplast, associated with a considerably acidic vacuolar pH, may exhaust cytosolic sugars in the flesh and alleviate the need for supplementary energisation of sugar transport at the plasma membrane.

scholarly journals A membrane-anchored E-type endo-1,4- -glucanase is localized on Golgi and plasma membranes of higher plants

1997 ◽  
Vol 94 (9) ◽  
pp. 4794-4799 ◽  
Author(s):  
D. A. Brummell ◽  
C. Catala ◽  
C. C. Lashbrook ◽  
A. B. Bennett
Keyword(s):  
Plasma Membranes ◽  
Higher Plants

Comparison of the biological activity of fusicoccin in higher plants with its binding to plasma membranes

Planta ◽  
1991 ◽  
Vol 183 (3) ◽  
Author(s):  
N.Yu. Abramycheva ◽  
A.V. Babakov ◽  
S.V. Bilushi ◽  
E.E. Danilina ◽  
V.P. Shevchenko
Keyword(s):  
Biological Activity ◽  
Plasma Membranes ◽  
Higher Plants

Calcium-activated, voltage-dependent, non-selective cation currents in endosperm plasma membrane from higher plants

1989 ◽  
Vol 237 (1287) ◽  
pp. 213-231 ◽  
Keyword(s):  
Plasma Membranes ◽  
Single Channel ◽  
Higher Plants ◽  
Outward Current ◽  
Monovalent Cation ◽  
Channel Blockers ◽  
Whole Cell ◽  
Whole Cell Patch Clamp ◽  
Single Burst ◽  
Subsequent Exposure

Single-channel and whole-cell patch-clamp techniques were used to characterize the electrophysiological behaviour of plasma membranes from freshly isolated, non-enzyme-treated endosperm protoplasts. A non-selective monovalent cation channel with a single-channel conductance of 22 pS in solutions with physiological potassium concentrations was observed in inside-out patches. The channel passes outward current at depolarized potentials and is highly selective for cations over anions, but discriminates poorly between lithium, sodium, potassium, rubidium and caesium ions. Specific potassium channel blockers were ineffective. The channel kinetics were apparently complex, with burst-like openings and rapid closures within a single burst. Single-channel openings were more frequent both for depolarizing pulses and maintained positive potentials. Channel activity was also increased by elevated cytoplasmic concentrations of either calcium or barium. Subsequent exposure of patches to low calcium, EGTA-buffered solutions resulted in large decreases in activity. Under whole-cell current clamp, small negative resting potentials were observed. A slowly developing outward current evoked by depolarizing pulses was seen in whole-cell recordings.

scholarly journals Protective mechanisms of melatonin against selenium toxicity in Brassica napus: insights into physiological traits, thiol biosynthesis and antioxidant machinery

2019 ◽  
Vol 19 (1) ◽  
Author(s):  
Zaid Ulhassan ◽  
Qian Huang ◽  
Rafaqat Ali Gill ◽  
Skhawat Ali ◽  
Theodore Mulembo Mwamba ◽  
...  
Keyword(s):  
Brassica Napus ◽  
Oxidative Damage ◽  
Antioxidant System ◽  
Crop Production ◽  
Plasma Membranes ◽  
Higher Plants ◽  
Photochemical Efficiency ◽  
Physiological Traits ◽  
Dependent Manner ◽  
Plant Tolerance

Abstract Background The ubiquitous signaling molecule melatonin (N-acetyl-5-methoxytryptamine) (MT) plays vital roles in plant development and stress tolerance. Selenium (Se) may be phytotoxic at high concentrations. Interactions between MT and Se (IV) stress in higher plants are poorly understood. The aim of this study was to evaluate the defensive roles of exogenous MT (0 μM, 50 μM, and 100 μM) against Se (IV) (0 μM, 50 μM, 100 μM, and 200 μM) stress based on the physiological and biochemical properties, thiol biosynthesis, and antioxidant system of Brassica napus plants subjected to these treatments. Results Se (IV) stress inhibited B. napus growth and biomass accumulation, reduced pigment content, and lowered net photosynthetic rate (Pn) and PSII photochemical efficiency (Fv/Fm) in a dose-dependent manner. All of the aforementioned responses were effectively alleviated by exogenous MT treatment. Exogenous MT mitigated oxidative damage and lipid peroxidation and protected the plasma membranes from Se toxicity by reducing Se-induced reactive oxygen species (ROS) accumulation. MT also alleviated osmotic stress by restoring foliar water and sugar levels. Relative to standalone Se treatment, the combination of MT and Se upregulated the ROS-detoxifying enzymes SOD, APX, GR, and CAT, increased proline, free amino acids, and the thiol components GSH, GSSG, GSH/GSSG, NPTs, PCs, and cys and upregulated the metabolic enzymes γ-ECS, GST, and PCS. Therefore, MT application attenuates Se-induce oxidative damage in plants. MT promotes the accumulation of chelating agents in the roots, detoxifies Se there, and impedes its further translocation to the leaves. Conclusions Exogenous MT improves the physiological traits, antioxidant system, and thiol ligand biosynthesis in B. napus subjected to Se stress primarily by enhancing Se detoxification and sequestration especially at the root level. Our results reveal better understanding of Se-phytotoxicity and Se-stress alleviation by the adequate supply of MT. The mechanisms of MT-induced plant tolerance to Se stress have potential implications in developing novel strategies for safe crop production in Se-rich soils. Graphical abstract

Hexose uptake by developing cotyledons of Vicia faba: physiological evidence for transporters of differing affinities and specificities

2005 ◽  
Vol 32 (11) ◽  
pp. 987 ◽  
Author(s):  
Gregory N. Harrington ◽  
Katherine E. Dibley ◽  
Raymond J. Ritchie ◽  
Christina E. Offler ◽  
John W. Patrick
Keyword(s):  
Vicia Faba ◽  
Plasma Membranes ◽  
Sugar Transport ◽  
Transfer Cell ◽  
Transport Mechanisms ◽  
Cell Complexes ◽  
Stage Of Development ◽  
Storage Parenchyma ◽  
Hexose Uptake ◽  
And Storage

Cotyledons of broad bean (Vicia faba L.) develop in an apoplasmic environment that shifts in composition from one dominated by hexoses to one dominated by sucrose. During the latter phase of development, sucrose / H+ symporter activity and expression is restricted to cotyledon epidermal transfer cell complexes that support sucrose fluxes that are 8.5-fold higher than those exhibited by the storage parenchyma. In contrast, the flux difference between these cotyledon tissues is only 1.7-fold for hexoses. Glucose and fructose uptake was shown to be sensitive to PCMBS and phloridzin, both of which slow H+-sugar transport. A low Km (or high affinity transporter, HAT) mechanism transports glucose and glucose-analogues exclusively. No HAT system for fructose could be found. A high Km (low affinity transporter, LAT) mechanism transports a broader range of hexoses, including glucose and fructose. Consistent with glucose and fructose transport being H+-coupled, their uptake was inhibited by dissipating the proton motive force (pmf) by treating cotyledons with carbonyl cyanide m-chlorophenol hydrazone, propionic acid or tetraphenylphosphonium ion. Erythrosin B inhibited hexose uptake, indicating a role for the P-type H+-ATPase in establishing the pmf. It is concluded that H+-coupled glucose and fructose transport mechanisms occur at plasma membranes of dermal transfer cell complexes and storage parenchyma cells. These transport mechanisms are active during pre- and storage phases of cotyledon development. However, hexose symport only makes a quantitative contribution to cotyledon biomass gain during the pre-storage stage of development.

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