scholarly journals Salmonella typhimurium HfrA, a mutant in which adenosine triphosphate can drive amino acid transport but not energy-dependent nicotinamide nucleotide transhydrogenation

1975 ◽  
Vol 150 (1) ◽  
pp. 21-29 ◽  
Author(s):  
W W Kay ◽  
P D Bragg
Keyword(s):  
Amino Acid ◽  
Salmonella Typhimurium ◽  
Energy Coupling ◽  
Amino Acid Uptake ◽  
Acid Uptake ◽  
Wild Type ◽  
Anaerobic Conditions ◽  
Dependent Transport ◽  
Energy Dependent ◽  
Aerobic And Anaerobic

In contrast with wild-type Salmonella typhimurium LT2, strain HfrA did not have ATP-driven energy-dependent transhydrogenase activity, although ATP-dependent quenching of atebrin fluorescence was normal. Respiration-dependent and energy-independent transhydrogenase, and Ca2+-activated ATPase (adenosine triphosphatase) activities were similar in both strains. Purified ATPases from the two strains had similar specific activities, similar subunit polypeptides, and were equally effective in restoring energy-dependent transhydrogenase activities to membrane particles of strain LT2 from which the ATPase had been stripped. The purified ATPases from both strains could restore respiration-dependent but not ATP-dependent transhydrogenation to stripped particles of strain HfrA. Both strains grew aerobically equally well on salts media containing glucose, malate, succinate, citrate, acetate, pyruvate, fumarate, lactate or aspartate as substrates. Growth on glucose under anaerobic conditions was similar. Strains LT2 and HfrA were equally effective in the accumulation under both aerobic and anaerobic conditions of the amino acids proline, phenylalanine, histidine, lysine, isoleucine and aspartic acid. Inhibition of amino acid accumulation by KCN and dicyclohexylcarbodi-imide occurred to the same extent in both strains. The complete inhibition by dicyclohexylcarbodi-imide of amino acid uptake under anaerobic conditions suggested that ATP could drive amino acid uptake in both strains. The ability of strain HfrA to carry out ATP-dependent transport or quenching of atebrin fluorescence but not ATP-dependent transhydrogenation is different from the wild-type strain and from any previously described energy-coupling mutant. It is difficult to reconcile the properties of this mutant with the chemiosmotic hypothesis.

Amino Acid Uptake by Amino Acid Analog Resistant Tobacco Cell Lines

1978 ◽  
Vol 33 (9-10) ◽  
pp. 634-640 ◽  
Author(s):  
Jochen Berlin ◽  
Jade M. Widholm
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Cell Line ◽  
Transport System ◽  
Amino Acid Uptake ◽  
Resistant Cell ◽  
Resistant Cell Line ◽  
Acid Uptake ◽  
Wild Type ◽  
Phenylalanine Transport

Abstract Two tobacco cell lines resistant to p-fiuorophenylalanine (PFP) and one resistant to 5-methyltryptophan (5-MT) are compared with wild type cells in their ability to absorb amino acids from the medium. One p-fluorophenylalanine-resistant cell line shows greatly reduced uptake of all amino acids so is resistant to growth inhibition by other amino acid analogs. The impaired absorption is noted with amino acids, amino acid analogs and shikimate, but not with cinnamate, salicylate, nicotine, glucose, 3-O-methylglucose and palmitate. The phenylalanine transport system of the PFP-resistant cell line and the wild type both have Km values of 90 µᴍ, but have different V max values. Several analogs of phenylalanine and several neutral L-amino acids inhibit the phenylalanine transport system, while ʟ-aspartic acid, ʟ-arginine, ᴅ-phenylalanine or chlorogenic acid do not interfere with the ʟ-phenylalanine uptake. The results indicate the presence of more than one transport system for amino acid uptake. The lessened uptake of all amino acids, the specificity of the uptake systems and the unchanged binding let us conclude that a pleiotropic mutation or that some inhibitor causes the reduced uptake of all amino acids by the PFP-resistant cell line.

Amino acid uptake profiling of wild type and recombinant Streptomyces lividans TK24 batch fermentations

2011 ◽  
Vol 152 (4) ◽  
pp. 132-143 ◽  
Author(s):  
Pieter-Jan D’Huys ◽  
Ivan Lule ◽  
Sven Van Hove ◽  
Dominique Vercammen ◽  
Christine Wouters ◽  
...  
Keyword(s):  
Amino Acid ◽  
Amino Acid Uptake ◽  
Streptomyces Lividans ◽  
Acid Uptake ◽  
Wild Type

scholarly journals Involvement of the stress-responsive transcription factor gene MSN2 in the control of amino acid uptake in Saccharomyces cerevisiae

2019 ◽  
Vol 19 (5) ◽  
Author(s):  
Noreen Suliani binti Mat Nanyan ◽  
Daisuke Watanabe ◽  
Yukiko Sugimoto ◽  
Hiroshi Takagi
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Amino Acid ◽  
Amino Acid Uptake ◽  
The Other ◽  
Acid Uptake ◽  
Wild Type ◽  
Transcription Factor Gene ◽  
Predominant Role ◽  
Intracellular Content ◽  
Higher Sensitivity

ABSTRACT The transcriptional factor Msn2 plays a pivotal role in response to environmental stresses by activating the transcription of stress-responsive genes in Saccharomyces cerevisiae. Our previous studies demonstrate that intracellular proline acts as a key protectant against various stresses. It is unknown, however, whether Msn2 is involved in proline homeostasis in S. cerevisiae cells. We here found that MSN2-overexpressing (MSN2-OE) cells showed higher sensitivity to a toxic analogue of proline, l-azetidine-2-carboxylic acid (AZC), as well as to the other amino acid toxic analogues, than wild-type cells. Overexpression of MSN2 increased the intracellular content of AZC, suggesting that Msn2 positively regulates the uptake of proline. Among the known proline permease genes, GNP1 was shown to play a predominant role in the AZC toxicity. Based on quantitative real-time PCR and western blot analyses, the overexpression of MSN2 did not induce any increases in the transcript levels of GNP1 or the other proline permease genes, while the amount of the Gnp1 protein was markedly increased in MSN2-OE cells. Microscopic observation suggested that the endocytic degradation of Gnp1 was impaired in MSN2-OE cells. Thus, this study sheds light on a novel link between the Msn2-mediated global stress response and the amino acid homeostasis in S. cerevisiae.

Is gamma-actin a regulator of amino acid transport?

1996 ◽  
Vol 270 (6) ◽  
pp. C1647-C1655 ◽  
Author(s):  
G. Lin ◽  
J. I. McCormick ◽  
R. M. Johnstone
Keyword(s):  
Amino Acid ◽  
Cell Line ◽  
Amino Acid Transport ◽  
Normal Growth ◽  
Amino Acid Uptake ◽  
Xenopus Laevis Oocytes ◽  
Amino Acid Transporters ◽  
Acid Uptake ◽  
Acid Transport ◽  
Dependent Transport

A mutated yeast cell line incapable of growth in minimal medium with proline as the sole nitrogen source was restored to normal growth by transfection with a cDNA from mouse Ehrlich cells. The cloned cDNA (E51) was found to be 90% homologous to gamma-actin. Immediately after transfection with E51 cDNA, both alpha-aminoisobutyric acid (AIB) and proline uptake in the mutated yeast were increased, particularly at pH 5. The expression of the same E51 cDNA also enhanced amino acid uptake in Xenopus laevis oocytes after injection into the Xenopus nuclei. A mutated mammalian lymphocyte cell line (GF-17), deficient in system A transport, also showed increased Na(+)-dependent transport after transfection with E51 cDNA. Whereas the mock transfected GF-17 cells failed to grow in the selection medium, the transfectants with E51 cDNA grew better than the untransfected cells. The data are consistent with the conclusion that expression of E51 cDNA can modify inactive, endogenous amino acid transporters, permitting substantial amino acid uptake in cells deficient in amino acid transporter(s) and permitting rapid cell growth. The data suggest that the gamma-actin-like protein coded for by E51 cDNA may play a significant regulatory role in amino acid transport.

Influence of insulin on amino acid uptake by lung slices

1977 ◽  
Vol 42 (2) ◽  
pp. 216-220 ◽  
Author(s):  
C. A. Gregorio ◽  
D. Massaro
Keyword(s):  
Amino Acids ◽  
Plasma Membrane ◽  
Amino Acid ◽  
Kinetic Analysis ◽  
Concentration Gradient ◽  
Diffusion Constant ◽  
Amino Acid Uptake ◽  
Acid Uptake ◽  
Rat Lung ◽  
Energy Dependent

We examined the transport of amino acids by rat lung slices using mainly 14C-labeled alpha-aminoisobutyric acid ([14C]AIB) as a nonmetabolized amino acid. We found that [14C]AIB is accumulated by the lung in an energy-dependent fashion against a concentration gradient. The uptake is saturable, stereospecific, and follows Michaelis-Menten kinetics suggesting enzyme or carrier mediation across the plasma membrane. Insulin increases the uptake of [14C]AIB and insulin plus glucose increases its uptake even more. The diffusion constant (KD) in the presence of glucose, insulin, or glucose plus insulin is the same, 0.29 h-1; the Vmax is also the same, 83.0 mmol-1–1-h-1, under these three conditions. The apparent Km is 14.0 mM with glucose, 9.0 mM with insulin, and 4.0 mM in the presence of glucose and insulin. We conclude that the uptake of [14C]AIB is increased by insulin, and insulin plus glucose, and, based on this kinetic analysis, this is due to an increased affinity of the transport sites for AIB (decreased Km, unchanged Vmax, and KD).

scholarly journals Helicobacter hepaticus Hydrogenase Mutants Are Deficient in Hydrogen-Supported Amino Acid Uptake and in Causing Liver Lesions in A/J Mice

2005 ◽  
Vol 73 (9) ◽  
pp. 5311-5318 ◽  
Author(s):  
Nalini S. Mehta ◽  
Stephane Benoit ◽  
Jagannatha V. Mysore ◽  
Renato S. Sousa ◽  
Robert J. Maier
Keyword(s):  
Amino Acid ◽  
Mutant Strain ◽  
Wild Type Strain ◽  
Amino Acid Uptake ◽  
Toxin Gene ◽  
Acid Uptake ◽  
Helicobacter Hepaticus ◽  
Wild Type ◽  
Hydrogenase Enzyme ◽  
Lobular Inflammation

ABSTRACT Helicobacter hepaticus, a causative agent of chronic hepatitis and hepatocellular carcinoma in mice, expresses a nickel-containing hydrogen-oxidizing hydrogenase enzyme. Growth of a hyaB gene-targeted mutant was unaffected by the presence of hydrogen, unlike the wild-type strain, which showed an enhanced growth rate when supplied with H2. Hydrogenase activities in H. hepaticus were constitutive and not dependent on the inclusion of H2 during growth. Addition of nickel during growth significantly stimulated both urease (for wild-type and hyaB) and hydrogenase (for wild-type) activities. In a 5-h period, the extent of 14C-labeled amino acid uptake by the wild type was markedly enhanced in the presence of hydrogen and was >5-fold greater than that of the hyaB mutant strain. In the presence of H2, the short-term whole-cell amino acid uptake V max of the parent strain was about 2.2-fold greater than for the mutant, but the half-saturation affinity for amino acid transport was the same for the parent and mutant strain. The liver- and cecum-colonizing abilities of the strains was estimated by real-time PCR quantitation of the H. hepaticus-specific cytolethal distending toxin gene and showed similar animal colonization for the hyaB mutant and the wild type. However, at 21 weeks postinoculation, the livers from mice inoculated with wild type exhibited moderate lobular lymphoplasmacytic hepatitis with hepatocytic coagulative necrosis, but the hydrogenase mutants exhibited no histological evidence of lobular inflammation or necrosis.

Chloramphenicol-resistant variants of Pseudomonas aeruginosa defective in amino acid transport

1980 ◽  
Vol 58 (10) ◽  
pp. 1165-1171 ◽  
Author(s):  
Jean E. Irvin ◽  
Jordan M. Ingram
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Amino Acid ◽  
Respiratory Activity ◽  
Amino Acid Uptake ◽  
Acid Uptake ◽  
Acid Transport ◽  
Transport Capacity ◽  
Wild Type ◽  
High Concentrations ◽  
High Level

High-level chloramphenicol (CM) resistant variants of Pseudomonas aeruginosa were isolated after culture of the wild-type (WT) strain in broth containing high concentrations of the drug. These variants exhibit reduced ability to accumulate several amino acids. The extent of reduction in transport capacity is a function of the concentration of CM in which the variants are grown. Respiratory activity is not reduced in these strains. Amino acid uptake is not affected by the presence of CM during assay. An isogenic strain carrying a plasmid coding for CM resistance does not show this response to CM. Transport capacity is restored to the WT level in CM-sensitive revertants. These results suggest that the acquisition of CM resistance in P. aeruginosa is associated with a fundamental alteration in membrane permeability which is regulated by metabolism in the presence of the drug. The ramifications of this for the study of CM action and resistance are discussed.

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