scholarly journals Stoicheiometrical proton and potassium ion movements accompanying the absorption of amino acids by the yeast Saccharomyces carlsbergensis

1971 ◽  
Vol 122 (5) ◽  
pp. 701-711 ◽  
Author(s):  
A. A. Eddy ◽  
J. A. Nowacki
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Energy Metabolism ◽  
Concentration Gradient ◽  
Metabolic Inhibitors ◽  
Ion Pump ◽  
Saccharomyces Carlsbergensis ◽  
Ion Movements ◽  
Proton Uptake ◽  
Amino Acid Carrier

1. Proton uptake into the yeast Saccharomyces carlsbergensis, was studied at pH4.5–5.5 in the presence of both antimycin and 2-deoxyglucose to inhibit energy metabolism. Previous work had shown that the cells then absorbed about 20nmol of glycine or l-phenylalanine against a considerable amino acid concentration gradient. The addition of the amino acid immediately stimulated the rate of uptake of protons two- to three-fold. About 2 extra equivalents of H+ accompanied a given amount of the amino acids into the yeast preparations exposed to the metabolic inhibitors for 2–4min and about 1.2 equivalents after 20min exposure. 2. Analogous observations were made during serial additions of glycine, l-phenylalanine, l-leucine and l-lysine to preparations lacking the metabolic inhibitors and deficient in substrates needed for energy metabolism. In fresh cellular preparations the influx of glycine was then closely coupled to a stimulated flow of 2.1 equiv. of H+ into the yeast. A similar number of K+ ions left the cells. About 30% of the extra protons was subsequently ejected from the yeast. Deoxyglucose and antimycin together inhibited the ejection of protons. When the yeast had been fed with glucose energy metabolism was stimulated and almost as many protons as were absorbed with the amino acid were apparently ejected again. 3. Yeast preparations containing Na+, instead of K+, as the principal cation absorbed about 1 extra equivalent of H+ after the addition of phenylalanine, glycine or leucine. This response was not observed in the presence of both deoxyglucose and antimycin. 4. The observations show that H+ and, in certain circumstances, K+ are co-substrates in the transport of the amino acids into the yeast. An analogy is drawn with the roles of Na+ and K+ as co-substrates in certain mammalian systems. The results lead to various models relating the physical flow of the co-substrate ions on the amino acid carrier to the transduction of chemical energy in an associated ion pump forming part of the mechanism for transporting amino acids into the yeast.

Effects of some Amino-acid and Purine Antagonists on Chick Embryos

Development ◽  
1958 ◽  
Vol 6 (2) ◽  
pp. 365-372
Author(s):  
C. H. Waddington ◽  
Margaret Perry
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Effective Concentration ◽  
Metabolic Inhibitors ◽  
Chick Embryos ◽  
Purine Analogue ◽  
Know How ◽  
Naturally Occurring ◽  
Different Types ◽  
Strong Action

Several authors have studied the effects on developing embryos of substances which are analogues of naturally occurring amino-acids and purines, and known to act, in other systems, as metabolic inhibitors. It was emphasized by Waddington, Feldman, & Perry (1955) that any particular substance may exhibit very different effects in embryos of different types. They found, for instance, that the purine analogue 8-azaguanine has a very strong action in the chick and a much lesser one in the newt embryo. It is therefore necessary to consider the various classes of embryos separately. In this communication we shall be concerned only with chick embryos. Substances under test can be administered to such embryos by injection through the shell, as was done in the paper cited above With this technique it is impossible to know how much diffusion takes place of the substance injected, and one cannot therefore be certain of the effective concentration which actually reaches the embryo.

Protein and energy metabolism in the pre-implantation cattle embryo

2001 ◽  
Vol 26 (2) ◽  
pp. 443-446 ◽  
Author(s):  
D.G. Morris ◽  
P. Humpherson ◽  
H.J. Leese ◽  
J.M. Sreenan
Keyword(s):  
Amino Acids ◽  
Protein Synthesis ◽  
Amino Acid ◽  
Energy Metabolism ◽  
Metabolic Rate ◽  
Protein Content ◽  
Amino Acid Uptake ◽  
Acid Uptake ◽  
Glucose Utilisation ◽  
Embryonic Loss

AbstractThere is no information on the metabolism of the cattle embryo during the period from day 8 to 16 a period of greatest embryonic loss. In this study the rate of protein synthesis and phosphorylation was measured in 13 to 15 day old cattle embryos. The rate of glucose utilisation and amino acid uptake/efflux by day 14 to 16 embryos was also measured. Protein synthesis and phosphorylation activity when expressed per unit of protein decreased with increasing embryo size and age. Similarly the rate of glucose utilisation was greatest for the earlier day 14 embryos. Embryos differed in their requirement for different amino acids. The pattern of uptake/efflux was similar to that of the earlier day 7 embryo. This study suggests that the metabolic rate of cattle embryos expressed per unit of protein content tends to decrease with increasing age and size from the initial burst of activity at day 13 around the time that expansion of the embryo begins.

scholarly journals The putative electrogenic nitrate-proton symport of the yeast Candida utilis. Comparison with the systems absorbing glucose or lactate

1985 ◽  
Vol 231 (2) ◽  
pp. 291-297 ◽  
Author(s):  
A A Eddy ◽  
P G Hopkins
Keyword(s):  
Amino Acids ◽  
Energy Metabolism ◽  
Candida Utilis ◽  
Membrane Depolarization ◽  
Yeast Cells ◽  
Charge Balance ◽  
Proton Symport ◽  
Limiting Nutrient ◽  
Proton Uptake ◽  
Aerobic Energy Metabolism

Strain N.C.Y.C. 193 of Candida utilis was grown aerobically at 30 degrees C with nitrate as limiting nutrient in a chemostat. The washed yeast cells depleted of ATP absorbed up to 5 nmol of nitrate/mg dry wt. of yeast. At pH 4-6, extra protons and nitrate entered the yeast cells together, in a ratio of about 2:1. Charge balance was maintained by an outflow of about 1 equiv. of K+. Nitrate stimulated the uptake of about 1 proton equivalent during glycolysis or aerobic energy metabolism. Studies with 3,3′-dipropylthiadicarbocyanine indicated that the proton-linked absorption of nitrate, amino acids or glucose depolarized the yeast cells. Proton uptake along with lactate led neither to net expulsion of K+ nor to membrane depolarization.

Amino acid assignment to one of three blood-brain barrier amino acid carriers

1976 ◽  
Vol 230 (1) ◽  
pp. 94-98 ◽  
Author(s):  
WH Oldendorf ◽  
J Szabo
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Blood Brain Barrier ◽  
Internal Standard ◽  
Basic Amino Acid ◽  
Brain Barrier ◽  
Carrier System ◽  
Blood Brain ◽  
Cross Inhibition ◽  
Amino Acid Carrier

The percentages of 22 14C-labeled amino acids remaining in rat brain 15 s after carotid injection were measured relative to a simultaneously injected diffusible internal standard, 3HOH. The injected solution also contained a nondiffusible internal standard, [113mIn]EDTA to correct for incomplete brain blood compartment washout. Self-inhibition and cross-inhibition was demonstrated by inclusion of unlabeled amino acids and carboxylic acids. All amino acids tested, excluding proline, alanine, and glycine, could be assigned to one, and only one, blood-brain barrier carrier system. The neutral carrier system transported phenylalanine, leucine, tyrosine, isoleucine, methionine, tryptophane, valine, DOPA, cysteine, histidine, threonine, glutamine, asparagine, and serine. Affinity for a basic amino acid carrier system was demonstrated for arginine, ornithine, and lysine. A third, low-capacity independent carrier system transporting aspartic and glutamic acids was demonstrated.

scholarly journals Comparison of the Nutritional Properties and Transcriptome Profiling Between the Two Different Harvesting Periods of Auricularia polytricha

2021 ◽  
Vol 8 ◽  
Author(s):  
Wenliang Wang ◽  
Yansheng Wang ◽  
Zhiqing Gong ◽  
Shifa Yang ◽  
Fengjuan Jia
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Energy Metabolism ◽  
Transcriptome Profiling ◽  
Nutritional Properties ◽  
Genetic Characteristics ◽  
Auricularia Polytricha ◽  
The Third ◽  
The Difference ◽  
Amino Acid Contents

Auricularia polytricha (A. polytricha), regarded as an edible and medical mushroom, has attracted toward the research interests because of the high nutrition and bioactivity. The nutritional and medical properties of A. polytricha have been well-studied; however, research about the difference of the nutritional properties and transcriptome profiling between the two different harvesting periods of A. polytricha was limited. In this study, the nutritional properties and transcriptome profiling were compared between the two different harvesting periods of A. polytricha: AP_S1 (the stage for the first harvesting period) and AP_S2 (the stage for the third harvesting period). This study showed that AP_S1 had the more growth advantages than AP_S2 including biomass, auricle area and thickness, protein and calcium contents, and most species of the amino acid contents, which contributed to the higher sensory evaluation and acceptability of AP_S1. Transcriptome profiling showed that a total of 30,298 unigenes were successfully annotated in the two different harvesting periods of A. polytricha. At a threshold of two-fold change, 1,415 and 3,213 unigenes were up- and downregulated, respectively. All the differentially expressed genes (DEGs) analysis showed that the some synthesis and metabolic processes were strengthened in AP_S1, especially the synthesis and metabolism of the amino acids and protein. The enhanced energy metabolism pathways could provide more energy for AP_S1 to synthesize the nutritional substance. Moreover, the expressions of 10 selected DEGs involved in the amino acid and protein synthesis pathways and energy metabolism pathways were higher in AP_S1 compared to AP_S2, consistent with Illumina analysis. To the best of our knowledge, this is the first study that compares the nutritional properties and transcriptome profiling between the two different harvesting periods of A. polytricha and the results can present insights into the growth and genetic characteristics of A. polytricha.

scholarly journals The concentration of amino acids by yeast cells depleted of adenosine triphosphate

1970 ◽  
Vol 120 (4) ◽  
pp. 853-858 ◽  
Author(s):  
A. A. Eddy ◽  
K. Backen ◽  
G. Watson
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Energy Metabolism ◽  
Adenosine Triphosphate ◽  
Physical Process ◽  
Ionic Species ◽  
Yeast Cells ◽  
Atp Content ◽  
Chemically Modified ◽  
Endogenous Amino Acids

1. The ATP content of preparations of a strain of Saccharomyces carlsbergensis was lowered below 0.3nmol/mg of yeast by starving the yeast cells in the presence of both antimycin and 5mm-deoxyglucose. 2. When the depleted cells were put at pH4.5 with glycine up to about 20nmol of the amino acid/mg of yeast was absorbed without being chemically modified. The mechanism did not depend on an exchange with endogenous amino acids. 3. The concentration of the absorbed glycine could apparently reach 100–200 times that outside the cells. 4. Replacement of the cellular K+ by Na+ almost stopped amino acid absorption in the presence of antimycin and deoxyglucose, but not in their absence. 5. It is suggested that, when energy metabolism itself had stopped, a purely physical process, namely the movements of H+ and K+ into and out of the yeast respectively, served to concentrate the amino acids in the cells. Both ionic species appear to be co-substrates of the system transporting amino acids.

scholarly journals Assessment of Carbon Substrate Catabolism Pattern and Functional Metabolic Pathway for Microbiota of Limestone Caves

2021 ◽  
Author(s):  
Suprokash Koner ◽  
Jung-Sheng Chen ◽  
Bing-Mu Hsu ◽  
Chao-Wen Tan ◽  
Cheng-Wei Fan ◽  
...  
Keyword(s):  
Amino Acids ◽  
Microbial Community ◽  
Amino Acid ◽  
Calcium Carbonate ◽  
Energy Metabolism ◽  
Carbon Source ◽  
16S Rrna ◽  
Bacterial Communities ◽  
Utilization Rate ◽  
Biolog Ecoplate

Abstract Microbially induced calcium carbonate precipitation (MICP), a widespread biochemical process involving heterotopic bacterial communities, generally occurs in organic matter-rich environments. Limestone caves, whose oligotrophic conditions result from the absence of sunlight, are considered an extreme environment. In such environments, bacteria have the potential to form calcium carbonate. In this study, the microbial community diversity and taxonomical structure outside and inside a limestone cave was investigated with their community-level carbon source by fingerprinting and functional metabolic pathway prediction using 16S rRNA amplicon sequencing analysis. The Biolog EcoPlate™ assay revealed that microbes from outside the cave were metabolically highly active, resulting in a rising carbon source utilization rate curve. Conversely, the microbial community within the cave was not very active in consuming the carbon substrates of Biolog EcoPlate™. Although major carbon sources were found to be used by microbial communities both inside and outside the cave, the microbial utilization rate of carbon bacteria inside was much lower than for bacteria outside the cave. The taxonomic classification of microbial diversity using 16S rRNA metagenomic analysis revealed eight predominant bacterial phyla associated with both sampling areas: Proteobacteria, Acidobacteria, Actinobacteria, Planctomycetes, Nitrospirae, Chloroflexi, Gemmatimonadetes, and Cyanobacteria. Among these, Planctomycetes, Proteobacteria, Cyanobacteria, and Nitrospirae were predominantly associated with external cave samples, whereas Acidobacteria, Actinobacteria, Chloroflexi, and Gemmatimonadetes were associated with internal cave samples. Functional prediction analysis showed that bacterial communities both inside and outside the cave were functionally involved in the metabolism of carbohydrates, amino acids, other amino acid, lipids, xenobiotic compounds, energy metabolism, and environmental information processing. However, the amino acid and carbohydrate metabolic pathways were predominantly linked to the external cave samples, while xenobiotic compounds, lipids, other amino acids, and energy metabolism were associated with internal cave samples. Overall, a positive correlation was observed between Biolog EcoPlate™ assay carbon utilization and metagenomically observed metabolic function.

Echinococcus granulosus: specificity of amino acid transport systems in protoscoleces

Parasitology ◽  
1987 ◽  
Vol 95 (1) ◽  
pp. 71-78 ◽  
Author(s):  
S. A. Jeffs ◽  
C. Arme
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Glutamic Acid ◽  
Echinococcus Granulosus ◽  
Concentration Gradient ◽  
Amino Acid Transport ◽  
Transport Systems ◽  
Acid Transport ◽  
Transport And Diffusion ◽  
And Diffusion

SUMMARYProtoscoleces ofEchinococcus granulosusabsorb the l-amino acids proline, methionine, leucine, alanine, serine, phenylalanine, lysine and glutamic acid by a combination of mediated transport and diffusion. All eight amino acids were accumulated against a concentration gradient. Comparison ofKtandVmaxvalues suggests that a low affinity for a particular compound is compensated for by a relatively larger number of transport sites for that compound. Four systems serve for the transport of the eight substrates studied: 2 for neutral (EgNl, EgN2) and 1 each for acidic (EgA) and basic (EgB) amino acids. All eight amino acids are incorporated into protein to varying degrees and substantial portions of absorbed l-alanine and l-methionine are metabolized into other compounds.

Sign in / Sign up

Export Citation Format

Share Document