Genetic studies of mutants in a high-affinity methionine transport system in Salmonella typhimurium

1989 ◽  
Vol 215 (2) ◽  
pp. 358-363 ◽  
Author(s):  
A. N. Cottam ◽  
P. D. Ayling
Keyword(s):  
Salmonella Typhimurium ◽  
Transport System ◽  
Genetic Studies ◽  
High Affinity ◽  
Methionine Transport

Citrate transport in Salmonella typhimurium: studies with 2-fluoro-L-erythro-citrate as a substrate

1980 ◽  
Vol 58 (10) ◽  
pp. 797-803 ◽  
Author(s):  
D. M. Ashton ◽  
G. D. Sweet ◽  
J. M. Somers ◽  
W. W. Kay
Keyword(s):  
Salmonella Typhimurium ◽  
Transport System ◽  
Protein C ◽  
Competitive Inhibitor ◽  
C Protein ◽  
High Affinity ◽  
Citrate Transport ◽  
Resistant Mutants ◽  
Dependent Transport ◽  
Energy Dependent

The citrate analogue, 2-fluoro-L-erythro-[3,4,5,6-14C]citrate was synthesized as a probe for the citrate transport system of Salmonella typhimurium. This analogue was actively transported by an inducible energy-dependent transport system with high affinity for fluorocitrate (Km = 3.3 μM), and this transport system was inhibited competitively by citrate and isocitrate. Fluorocitrate was shown to be a competitive inhibitor of the citrate-binding protein (C protein) of this organism (Ki = 4–5 μM). Analogue resistant mutants were simultaneously defective in fluorocitrate transport as well as the C protein and the affected allele, tctC, was located at 59 units on the S. typhimurium chromosome map. These tctC mutants were shown to be specifically defective in K+-dependent fluorocitrate transport but still retained another system capable of transporting fluorocitrate in the presence of both Na+ and K+.

Regulation of the High-Affinity Nitrate Transport System in Wheat Roots by Exogenous Abscisic Acid and Glutamine

2007 ◽  
Vol 49 (12) ◽  
pp. 1719-1725 ◽  
Author(s):  
Chao Cai ◽  
Xue-Qiang Zhao ◽  
Yong-Guan Zhu ◽  
Bin Li ◽  
Yi-Ping Tong ◽  
...  
Keyword(s):  
Abscisic Acid ◽  
Transport System ◽  
Nitrate Transport ◽  
Wheat Roots ◽  
High Affinity

scholarly journals RCO-3 and COL-26 form an external-to-internal module that regulates the dual-affinity glucose transport system in Neurospora crassa

2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Jinyang Li ◽  
Qian Liu ◽  
Jingen Li ◽  
Liangcai Lin ◽  
Xiaolin Li ◽  
...  
Keyword(s):  
Transcription Factor ◽  
Neurospora Crassa ◽  
Glucose Transport ◽  
Transport System ◽  
Rational Design ◽  
Glucose Sensor ◽  
Glucose Transporters ◽  
Glucose Fluctuation ◽  
High Affinity ◽  
Glucose Transport System

Abstract Background Low- and high-affinity glucose transport system is a conserved strategy of microorganism to cope with environmental glucose fluctuation for their growth and competitiveness. In Neurospora crassa, the dual-affinity glucose transport system consists of a low-affinity glucose transporter GLT-1 and two high-affinity glucose transporters HGT-1/HGT-2, which play diverse roles in glucose transport, carbon metabolism, and cellulase expression regulation. However, the regulation of this dual-transporter system in response to environmental glucose fluctuation is not yet clear. Results In this study, we report that a regulation module consisting of a downstream transcription factor COL-26 and an upstream non-transporting glucose sensor RCO-3 regulates the dual-affinity glucose transport system in N. crassa. COL-26 directly binds to the promoter regions of glt-1, hgt-1, and hgt-2, whereas RCO-3 is an upstream factor of the module whose deletion mutant resembles the Δcol-26 mutant phenotypically. Transcriptional profiling analysis revealed that Δcol-26 and Δrco-3 mutants had similar transcriptional profiles, and both mutants had impaired response to a glucose gradient. We also showed that the AMP-activated protein kinase (AMPK) complex is involved in regulation of the glucose transporters. AMPK is required for repression of glt-1 expression in starvation conditions by inhibiting the activity of RCO-3. Conclusions RCO-3 and COL-26 form an external-to-internal module that regulates the glucose dual-affinity transport system. Transcription factor COL-26 was identified as the key regulator. AMPK was also involved in the regulation of the dual-transporter system. Our findings provide novel insight into the molecular basis of glucose uptake and signaling in filamentous fungi, which may aid in the rational design of fungal strains for industrial purposes.

scholarly journals Functional Characterization of a High-Affinity Choline Transport System in Human Keratinocytes

2002 ◽  
Vol 119 (1) ◽  
pp. 118-121 ◽  
Author(s):  
Kathrin Hoffmann ◽  
Franziska Grafe ◽  
Wolfgang Wohlrab ◽  
Reinhard H. Neubert ◽  
Matthias Brandsch
Keyword(s):  
Transport System ◽  
Functional Characterization ◽  
Human Keratinocytes ◽  
Choline Transport ◽  
High Affinity

scholarly journals Corrigendum to: A high affinity nitrate transport system from Chlamydomonas requires two gene products (FEBS 23233)

FEBS Letters ◽  
2000 ◽  
Vol 481 (1) ◽  
pp. 88-88
Author(s):  
Jing-Jiang Zhou ◽  
Emilio Fernández ◽  
Aurora Galván ◽  
Anthony J. Miller
Keyword(s):  
Transport System ◽  
Nitrate Transport ◽  
Gene Products ◽  
High Affinity
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