Construction of Bacterial Cells with an Active Transport System for Unnatural Amino Acids

2019 ◽  
Vol 8 (5) ◽  
pp. 1195-1203 ◽  
Author(s):  
Wooseok Ko ◽  
Rahul Kumar ◽  
Sanggil Kim ◽  
Hyun Soo Lee
Keyword(s):  
Amino Acids ◽  
Active Transport ◽  
Transport System ◽  
Unnatural Amino Acids ◽  
Bacterial Cells ◽  
Active Transport System

Uptake of L-proline by Histoplasma capsulatum

1976 ◽  
Vol 22 (8) ◽  
pp. 1188-1190 ◽  
Author(s):  
Nina Dabrowa ◽  
Dexter H. Howard
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Active Transport ◽  
Transport System ◽  
Histoplasma Capsulatum ◽  
Yeast Cells ◽  
Side Chain ◽  
Simple Diffusion ◽  
Aliphatic Side Chain ◽  
Active Transport System

The uptake and incorporation of L-proline by yeast cells of the dimorphic zoopathogen Histoplasma capsulatum were studied. The amino acid was assimilated in at least two ways: by an active transport system with a Km of 1.7 × 10−5 M and by simple diffusion. The active transport system was stereospecific and severely restricted to neutral aliphatic side-chain amino acids. Certain analogues inhibited L-proline uptake and prevented incorporation of the amino acid into cellular constituents. The inhibition of L-proline uptake by L-leucine was competitive. Since L-leucine and L-proline are seemingly transported by a system with similarcharacteristics, it must be concluded, as originally postulated, that the buckled ring of L-proline, in solution, acts as an aliphatic side chain and that this cyclic amino acid is transported by a system more or less specific for amino acids with neutral aliphatic side chains.

On the structural organization of biological pumps and channels

1984 ◽  
Vol 42 ◽  
pp. 138-141
Author(s):  
G. Zampighi ◽  
M. Kreman
Keyword(s):  
Active Transport ◽  
Transport System ◽  
Plasma Membranes ◽  
Transport Proteins ◽  
Molecular Organization ◽  
Passive Transport ◽  
Concentration Gradients ◽  
Cell Functions ◽  
Natural Concentration ◽  
Active Transport System

The plasma membranes of most animal cells contain transport proteins which function to provide passageways for the transported species across essentially impermeable lipid bilayers. The channel is a passive transport system which allows the movement of ions and low molecular weight molecules along their concentration gradients. The pump is an active transport system and can translocate cations against their natural concentration gradients. The actions and interplay of these two kinds of transport proteins control crucial cell functions such as active transport, excitability and cell communication. In this paper, we will describe and compare several features of the molecular organization of pumps and channels. As an example of an active transport system, we will discuss the structure of the sodium and potassium ion-activated triphosphatase [(Na+ +K+)-ATPase] and as an example of a passive transport system, the communicating channel of gap junctions and lens junctions.

scholarly journals Actions of external hypertonic urea, ADH, and theophylline on transcellular and extracellular solute permeabilities in frog skin.

1975 ◽  
Vol 65 (5) ◽  
pp. 599-615 ◽  
Author(s):  
L J Mandel
Keyword(s):  
Linear Relationship ◽  
Active Transport ◽  
Transport System ◽  
Frog Skin ◽  
Open Circuit Potential ◽  
Open Circuit ◽  
Solute Permeability ◽  
Parallel Lines ◽  
Paracellular Pathways ◽  
Active Transport System

Increases in transepithelial solute permeability were elicited in the frog skin with external hypertonic urea, theophylline, and vasopressin (ADH). In external hypertonic urea, which is known to increase the permeability of the extracellular (paracellular) pathway, the unidirectional transepithelial fluxes of Na (passive), K, Cl, and urea increased substantially while preserving a linear relationship to each other. The same linear relationship was also observed for the passive Na and urea fluxes in regular Ringer and under stimulation with ADH or 10 mM theophylline, indicating that their permeation pathway was extracellular. A linear relationship between Cl and urea fluxes could be demonstrated if the skins were separated according to their open circuit potentials; parallel lines were obtained with increasing intercepts on the Cl axis as the open circuit potential decreased. The slopes of the Cl vs. urea lines were not different from that obtained in external hypertonic urea, indicating that this relationship described the extracellular movement of Cl. The intercept on the ordinate was interpreted as the contribution from the transcellular Cl movement. In the presence of 0.5 mM theophylline or 10 mU/ml of ADH, mainly the transcellular movement of Cl increased, whereas 10 mM theophylline caused increases in both transcellular and extracellular Cl fluxes. These and other data were interpreted in terms of a possible intracellular control of the theophylline-induced increase in extracellular fluxes. The changes in passive solute permeability were shown to be independent of active transport. The responses of the active transport system, the transcellular and paracellular pathways to theophylline and ADH could be explained in terms of the different resulting concentrations of cyclic 3'-5'-AMP produced by each of these substances in the tissue.

scholarly journals Expanded toolbox for directing the biosynthesis of macrocyclic peptides in bacterial cells

2020 ◽  
Vol 11 (24) ◽  
pp. 6202-6208
Author(s):  
Jacob A. Iannuzzelli ◽  
Rudi Fasan
Keyword(s):  
Amino Acids ◽  
Unnatural Amino Acids ◽  
Bacterial Cells ◽  
Macrocyclic Peptides ◽  
Live Bacteria

A new suite of unnatural amino acids is reported for directing the biosynthesis of genetically encoded macrocyclic peptides in live bacteria.

A linked active transport system for Na+ and K+ in a glial cell line

1976 ◽  
Vol 104 (1) ◽  
pp. 93-105 ◽  
Author(s):  
Gary Kukes ◽  
Jean De Vellis ◽  
Rafael Elul
Keyword(s):  
Cell Line ◽  
Glial Cell ◽  
Active Transport ◽  
Transport System ◽  
Active Transport System

The pH-dependent uptake of putrescine by Pseudomonas acidovorans and its incorporation into bacteriophage DNA

1983 ◽  
Vol 29 (7) ◽  
pp. 827-829 ◽  
Author(s):  
D. L. Bruce ◽  
R. A. J. Warren
Keyword(s):  
Active Transport ◽  
Transport System ◽  
Normal Condition ◽  
Intracellular Pool ◽  
Pseudomonas Acidovorans ◽  
Ph Dependent ◽  
Active Transport System

Lack of an active transport system prevents Pseudomonas acidovorans taking up putrescine under normal condition of growth. At pH 9.5, however, putrescine does enter the cell. That putrescine enters the intracellular pool is shown by its conversion to 2-hydroxyputrescine and spermidine after the cells are returned to pH 7.0. The accumulated putrescine can be used to label specifically the α-putrescinylthymine residues of bacteriophage [Formula: see text] DNA.

Participation of an active transport system in berberine-secreting cultured cells of Thalictrum minus

1987 ◽  
Vol 6 (5) ◽  
pp. 356-359 ◽  
Author(s):  
H. Yamamoto ◽  
M. Suzuki ◽  
Y. Suga ◽  
H. Fukui ◽  
M. Tabata
Keyword(s):  
Active Transport ◽  
Transport System ◽  
Cultured Cells ◽  
Thalictrum Minus ◽  
Active Transport System
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