Neutral Amino Acid Transport in Astrocytes: Characterization of Na+-Dependent and Na+-Independent Components of ?-Aminoisobutyric Acid Uptake

1988 ◽  
Vol 51 (6) ◽  
pp. 1913-1918 ◽  
Author(s):  
N. Brookes
Keyword(s):  
Amino Acid ◽  
Amino Acid Transport ◽  
Neutral Amino Acid ◽  
Acid Uptake ◽  
Acid Transport ◽  
Aminoisobutyric Acid ◽  
Independent Components

Active Transport of α-Aminoisobutyric Acid by the Isolated Midgut of Hyalophora Cecropia

1972 ◽  
Vol 56 (1) ◽  
pp. 167-172
Author(s):  
SIGNE NEDERGAARD
Keyword(s):  
Amino Acid ◽  
Active Transport ◽  
Opposite Direction ◽  
Amino Acid Transport ◽  
Amino Acid Uptake ◽  
Acid Uptake ◽  
Acid Transport ◽  
Active Process ◽  
Aminoisobutyric Acid ◽  
Amino Acid Flux

1. The α-aminoisobutyric acid flux from lumen to blood of the isolated Cecropia midgut is around 17 µmole/h, while the amino acid flux in the opposite direction is on average 0.3 µmole/h. 2. The amino acid uptake is inhibited by lack of oxygen. It is suggested that the amino acid transport from lumen to blood is an active process. 3. The amino acid uptake is inhibited by short-circuiting the midgut potential, indicating that there is no direct correlation between the active transport of potassium and the uptake of the amino acid by the midgut.

scholarly journals The amino acid transporter OsAAP4 contributes to rice tillering and grain yield by regulating neutral amino acid transport through two splicing variants

2020 ◽  
Author(s):  
Zhongming Fang ◽  
Bowen Wu ◽  
Yuanyuan Ji
Keyword(s):  
Amino Acid ◽  
Grain Yield ◽  
Amino Acid Transport ◽  
Growth And Development ◽  
Neutral Amino Acid ◽  
Acid Uptake ◽  
Acid Transport ◽  
Splicing Variant ◽  
Rice Growth ◽  
Splicing Variants

Abstract Background Amino acids, which are transported by amino acid transporters, are the major forms of organic nitrogen utilized by higher plants. Among the 19 Amino Acid Permease transporters (AAPs) in rice, only a small number of these genes have been reported to influence rice growth and development. However, whether other OsAAPs are responsible for rice growth and development is unclear. Results In this study, we demonstrate that OsAAP4 promoter sequences are divergent between Indica and Japonica, with higher expression in the former, which produces more tillers and higher grain yield than does Japonica. Overexpression of two different splicing variants of OsAAP4 in Japonica ZH11 significantly increased rice tillering and grain yield as result of enhancing the neutral amino acid concentrations of Val, Pro, Thr and Leu. OsAAP4 RNA interference (Ri) and mutant lines displayed opposite trends. In addition, exogenous Val or Pro at 0.5 mM significantly promoted the bud outgrowth of lines overexpressing an OsAAP4a splicing variant compared with ZH11, and exogenous Val or Pro at 2.0 mM significantly enhanced the bud outgrowth of lines overexpressing splicing variant OsAAP4b compared with ZH11. Of note, the results of a protoplast amino acid-uptake assay showed that Val or Pro at different concentrations was specifically transported and accumulated in these overexpressing lines. Transcriptome analysis further demonstrated that OsAAP4 may affect nitrogen transport and metabolism, and auxin, cytokinin signaling in regulating rice tillering. Conclusion Our results suggested that OsAAP4 contributes to rice tiller and grain yield by regulating neutral amino acid transport through two different splicing variants and that OsAAP4 might have potential applications in rice breeding.

Puromycin effect on amino acid transport: differential rates of carrier protein turnover

1975 ◽  
Vol 228 (1) ◽  
pp. 23-26 ◽  
Author(s):  
JM Phang ◽  
DL Valle ◽  
L Fisher ◽  
A Granger
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Amino Acid Transport ◽  
Half Life ◽  
Transport Systems ◽  
Acid Uptake ◽  
Acid Transport ◽  
Aminoisobutyric Acid ◽  
Fetal Rat ◽  
Protein Components

In fetal rat calvaria, puromycin selectively inhibited the uptake of certain groups of amino acids. Puromycin treatment decreased the uptake of glycine, L-proline, and alpha-aminoisobutyric acid but was without effect on the active uptake of all other amino acids tested. In studies of alpha-aminoisobutyric acid uptake, puromycin decreased the maximal transport velocity by 70% but had no effect on the affinity of the transport system for the amino acid. With puromycin treatment, the fall-off in rates of alpha-aminoisobutyric acid uptake was first order with a half-life of 68 min. Insulin treatment increased this half-life to 118 min. These findings suggest that protein components of specific transport systems are degraded at varying rates after puromycin blockade of protein synthesis. Hormones that stimulate amino acid transport (e.g., insulin) may decrease the rate of degradation of these protein components.

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