Sugar transport

2011 ◽  
Author(s):  
Arianne Heinrichs
Keyword(s):  
Sugar Transport

Kinetic analysis of mechanism of intestinal Na+-dependent sugar transport

1985 ◽  
Vol 248 (5) ◽  
pp. C498-C509 ◽  
Author(s):  
D. Restrepo ◽  
G. A. Kimmich
Keyword(s):  
Experimental Data ◽  
Steady State ◽  
Sugar Transport ◽  
Enzyme Kinetic ◽  
Steady State Distribution ◽  
State Distribution ◽  
Least Squares Fit ◽  
Coupling Stoichiometry ◽  
Rate Limiting ◽  
Kinetics Of

Zero-trans kinetics of Na+-sugar cotransport were investigated. Sugar influx was measured at various sodium and sugar concentrations in K+-loaded cells treated with rotenone and valinomycin. Sugar influx follows Michaelis-Menten kinetics as a function of sugar concentration but not as a function of Na+ concentration. Nine models with 1:1 or 2:1 sodium:sugar stoichiometry were considered. The flux equations for these models were solved assuming steady-state distribution of carrier forms and that translocation across the membrane is rate limiting. Classical enzyme kinetic methods and a least-squares fit of flux equations to the experimental data were used to assess the fit of the different models. Four models can be discarded on this basis. Of the remaining models, we discard two on the basis of the trans sodium dependence and the coupling stoichiometry [G. A. Kimmich and J. Randles, Am. J. Physiol. 247 (Cell Physiol. 16): C74-C82, 1984]. The remaining models are terter ordered mechanisms with sodium debinding first at the trans side. If transfer across the membrane is rate limiting, the binding order can be determined to be sodium:sugar:sodium.

scholarly journals Sugar Transport

1973 ◽  
Vol 248 (3) ◽  
pp. 957-965 ◽  
Author(s):  
Robert D. Simoni ◽  
John B. Hays ◽  
Teruko Nakazawa ◽  
Saul Roseman
Keyword(s):  
Sugar Transport

scholarly journals Plant SWEETs: from sugar transport to plant–pathogen interaction and more unexpected physiological roles

2021 ◽  
Author(s):  
Richard Breia ◽  
Artur Conde ◽  
Hélder Badim ◽  
Ana Margarida Fortes ◽  
Hernâni Gerós ◽  
...  
Keyword(s):  
Plant Pathogen ◽  
Sugar Transport ◽  
High Capacity ◽  
Phloem Loading ◽  
Transcription Activator ◽  
Pythium Irregulare ◽  
Clear Cut ◽  
Opposite Behavior ◽  
Plant Pathogen Interaction ◽  
Plant Pathogen Interactions

Abstract Sugars Will Eventually be Exported Transporters (SWEETs) have important roles in numerous physiological mechanisms where sugar efflux is critical, including phloem loading, nectar secretion, seed nutrient filling, among other less expected functions. They mediate low affinity and high capacity transport, and in angiosperms this family is composed by 20 paralogs on average. As SWEETs facilitate the efflux of sugars, they are highly susceptible to hijacking by pathogens, making them central players in plant–pathogen interaction. For instance, several species from the Xanthomonas genus are able to upregulate the transcription of SWEET transporters in rice (Oryza sativa), upon the secretion of transcription-activator-like effectors. Other pathogens, such as Botrytis cinerea or Erysiphe necator, are also capable of increasing SWEET expression. However, the opposite behavior has been observed in some cases, as overexpression of the tonoplast AtSWEET2 during Pythium irregulare infection restricted sugar availability to the pathogen, rendering plants more resistant. Therefore, a clear-cut role for SWEET transporters during plant–pathogen interactions has so far been difficult to define, as the metabolic signatures and their regulatory nodes, which decide the susceptibility or resistance responses, remain poorly understood. This fuels the still ongoing scientific question: what roles can SWEETs play during plant–pathogen interaction? Likewise, the roles of SWEET transporters in response to abiotic stresses are little understood. Here, in addition to their relevance in biotic stress, we also provide a small glimpse of SWEETs importance during plant abiotic stress, and briefly debate their importance in the particular case of grapevine (Vitis vinifera) due to its socioeconomic impact.

scholarly journals Sweet versus grain sorghum: Differential sugar transport and accumulation are linked with vascular bundle architecture

2021 ◽  
Vol 167 ◽  
pp. 113550
Author(s):  
Adnan Kanbar ◽  
Ehsan Shakeri ◽  
Dema Alhajturki ◽  
Michael Riemann ◽  
Mirko Bunzel ◽  
...  
Keyword(s):  
Vascular Bundle ◽  
Sugar Transport ◽  
Grain Sorghum
Sign in / Sign up

Export Citation Format

Share Document