Most nutrients and ions in bacteria, yeasts, algae, and plants are transported uphill at the expense of a gradient of the electrochemical potential of protons deltamu-H+ (a type of secondary active transport). Diagnosis of such transports rests on the determination of the transmembrane electrical potential difference deltapsi and the difference of pH at the two membrane sides. The behavior of kinetic parameters K(T) (the half-saturation constant) and J(max), (the maximum rate of transport) upon changing driving ion concentrations and electrical potentials may be used to determine the molecular details of the transport reaction. Equilibrium accumulation ratios of driven solutes are expected to be in agreement with the deltapsi and deltapH measured independently, as well as with the Haldane-type expression involving K(T) and J(max). Different stoichiometries of H+/solute, as well as intramembrane effects of pH and deltapsi, may account for some of the observed inconsistencies.

• MeSH
• biologické modely MeSH
• elektrochemie MeSH
• iontový transport fyziologie   MeSH
• kinetika MeSH
• koncentrace vodíkových iontů MeSH
• membránové potenciály MeSH
• protonmotorická síla fyziologie   MeSH
• termodynamika MeSH
• Publikační typ
• časopisecké články MeSH
• přehledy MeSH

Neither exit nor counterflow efflux of thiamin, taken up previously by an active transport, were found in Saccharomyces cerevisiae, in either the wild type or a mutant with a lower rate of thiamin phosphorylation. Complete inhibition of thiamin phosphorylation by oxythiamin did not lead to any release of thiamin taken up by the cell.

• MeSH
• aktivní transport účinky léků   MeSH
• fosforylace MeSH
• kinetika MeSH
• mutace MeSH
• oxythiamin farmakologie   MeSH
• Saccharomyces cerevisiae genetika   růst a vývoj   metabolismus   MeSH
• thiamin antagonisté a inhibitory   metabolismus   MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• oxythiamin MeSH
• thiamin MeSH

• Klíčová slova
• CALCIUM *, CALCIUM ISOTOPES *, EXPERIMENTAL LAB STUDY *, KIDNEY *, METABOLISM *, RABBITS *,
• MeSH
• iontový transport * MeSH
• izotopy vápníku * MeSH
• králíci MeSH
• kůra ledviny * MeSH
• ledviny * MeSH
• metabolismus * MeSH
• vápník dietní * MeSH
• vápník * MeSH
• výzkum * MeSH
• zvířata MeSH
• Check Tag
• králíci MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• izotopy vápníku * MeSH
• vápník dietní * MeSH
• vápník * MeSH

• MeSH
• azidy farmakologie   MeSH
• Bacteria metabolismus   MeSH
• dusičnany metabolismus   MeSH
• koncentrace vodíkových iontů MeSH
• kultivační média MeSH
• kyanidy farmakologie   MeSH
• spotřeba kyslíku MeSH
• teplota MeSH
• thiosírany metabolismus   MeSH
• transport elektronů * MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• azidy MeSH
• dusičnany MeSH
• kultivační média MeSH
• kyanidy MeSH
• thiosírany MeSH

The strictly aerobic yeast Candida parapsilosis transports the nonmetabolizable monosaccharide 6-deoxy-D-glucose by an active process (inhibition by 2.4-dinitrophenol and other uncouplers but not by iodoacetamide), the accumulation ratio decreasing with increasing substrate concentration. Measured accumulation ratios are in agreement with those predicted from kinetic constants for influx and efflux. Energy for transport is probably required in the translocation step. The maximum rate is temperature-dependent with a transition point at 21 degrees C. the accumulation ratio is not. The uptake is most active at pH 4.5--8.5. It appears not to involve stoichiometric proton symport. The transport system is shared by D-glucose, D-mannose, D-galactose and possibly maltose but not by fructose, sucrose or pentoses. The apparent half-life of the transport system was 3.5--4 h.

• MeSH
• aerobióza MeSH
• aktivní transport účinky léků   MeSH
• aminokyseliny metabolismus   MeSH
• Candida metabolismus   MeSH
• deoxycukry metabolismus   MeSH
• deoxyglukosa metabolismus   MeSH
• dicyklohexylkarbodiimid farmakologie   MeSH
• dinitrofenoly farmakologie   MeSH
• dusičnan uranylu farmakologie   MeSH
• jodacetamid farmakologie   MeSH
• karbonylkyanid-m-chlorfenylhydrazon farmakologie   MeSH
• kinetika MeSH
• koncentrace vodíkových iontů MeSH
• metabolismus sacharidů MeSH
• teplota MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• aminokyseliny MeSH
• deoxycukry MeSH
• deoxyglukosa MeSH
• dicyklohexylkarbodiimid MeSH
• dinitrofenoly MeSH
• dusičnan uranylu MeSH
• jodacetamid MeSH
• karbonylkyanid-m-chlorfenylhydrazon MeSH

Transport systems for amino acids in the wild-type strain of Schizosaccharomyces pombe are not constitutive. During growth on different media no transport of acidic, neutral and basic amino acids is detectable. To acquire the ability to transport amino acids, cells must be preincubated with a metabolic source of energy, such as glucose. The appearance of transport activity is associated with protein synthesis (suppression by cycloheximide) at all phases of culture growth. After such preincubation the initial rate of amino acid uptake depends on the phase of growth of the culture and on the amount of glucose in the growth medium but not on the nitrogen source used. L-Proline and 2-aminoisobutyric acid are practically not transported under any of the conditions tested.

• MeSH
• aktivní transport MeSH
• aminokyseliny farmakokinetika   MeSH
• cykloheximid farmakologie   MeSH
• fungální proteiny biosyntéza   MeSH
• kinetika MeSH
• kultivační média MeSH
• kyseliny aminoisomáselné farmakokinetika   MeSH
• prolin farmakokinetika   MeSH
• Saccharomycetales metabolismus   MeSH
• Schizosaccharomyces účinky léků   růst a vývoj   metabolismus   MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• 2-aminoisobutyric acid MeSH Prohlížeč
• aminokyseliny MeSH
• cykloheximid MeSH
• fungální proteiny MeSH
• kultivační média MeSH
• kyseliny aminoisomáselné MeSH
• prolin MeSH

Acyclic polyols (erythritol, xylitol, ribitol, D-arabinitol, mannitol, sorbitol and galactitol) are not metabolized by Saccharomyces cerevisiae. They are taken up by a fast non-active process, reaching 40-70% distribution referred to total cell water. The uptake is insensitive to temperature, pH (between 4 and 8), 2,4-dinitrophenol and uranyl ions. Its initial rate rises linearly with concentration from 10(-5)M to 1M. The process resembles simple diffusion through large pores or the trapping of the whole solution on the surface. Protoplasts behave like whole cells in this respect. Only erythritol shows a second type of uptake which is inhibitor-insensitive but temperature-dependent.

• MeSH
• aktivní transport MeSH
• buněčná membrána metabolismus   MeSH
• cukerné alkoholy metabolismus   MeSH
• dinitrofenoly farmakologie   MeSH
• kinetika MeSH
• koncentrace vodíkových iontů MeSH
• polysacharidy metabolismus   MeSH
• protoplasty metabolismus   MeSH
• Saccharomyces cerevisiae metabolismus   MeSH
• teplota MeSH
• uran farmakologie   MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• cukerné alkoholy MeSH
• dinitrofenoly MeSH
• polysacharidy MeSH
• uran MeSH

The in vivo inflow rate of low density lipoprotein (LDL) cholesterol to the thoracic aorta, renal and coronary arteries was studied in minipigs with endogenously labelled 3H-cholesterol LDL. The LDL cholesterol inflow rate to these arteries was three to five times higher in animals with hypercholesterolemia and experimental atherosclerosis compared to the controls. Moreover, the inflow rate of LDL cholesterol to the control intact arteries was so high that the cumulation of arterial cholesterol cannot be regarded simply as one-way transport and the amount of cholesterol present in the arterial wall is the result of the equilibrium between LDL cholesterol inflow and transport out from the wall.

• MeSH
• aktivní transport MeSH
• arterie metabolismus   MeSH
• arterioskleróza metabolismus   MeSH
• hypercholesterolemie metabolismus   MeSH
• LDL-cholesterol metabolismus   MeSH
• miniaturní prasata MeSH
• prasata MeSH
• zvířata MeSH
• Check Tag
• mužské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• LDL-cholesterol MeSH

In the facultatively anaerobic yeast Saccharomyces cerevisiae the uptake rate and the accumulation ratio of 2-aminoisobutyric acid was decreased by some 30% by Fenton's reagent (FR), a powerful source of OH. radicals. Likewise, the uptake of glutamic acid, leucine and arginine was diminished. The mediated diffusion of 6-deoxy-D-glucose was not affected. The H+ symport of maltose and trehalose was inhibited by some 40% both in the initial rate and in the accumulation ratio. FR had a dramatic inhibitory effect when present during preincubation with 50 mmol/L glucose. In the obligately aerobic Lodderomyces elongisporus the uptake of all amino acids tested was decreased by 15-30%, that of 6-deoxy-D-glucose by about 10%. The initial rates of uptake of maltose and trehalose were depressed by FR by 40% and the acceleration of uptake observed after 8 min of incubation, was abolished by FR completely. Acidification rate of the external medium by S. cerevisiae in the presence of glucose or galactose was enhanced three-fold, that after subsequently added K+ was substantially decreased. FR appears to have a dual effect on sugar and amino acid transport processes in yeast: (1) it blocks carrier protein synthesis; (2) it inhibits the source of energy for transport. It does not appreciably affect the carrier proteins themselves.

• MeSH
• aktivní transport účinky léků   MeSH
• aminokyseliny metabolismus   MeSH
• fungální proteiny metabolismus   MeSH
• kinetika MeSH
• koncentrace vodíkových iontů MeSH
• metabolismus sacharidů MeSH
• peroxid vodíku farmakologie   MeSH
• Saccharomyces cerevisiae účinky léků   metabolismus   MeSH
• Saccharomycetales účinky léků   metabolismus   MeSH
• transportní proteiny metabolismus   MeSH
• železo farmakologie   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• aminokyseliny MeSH
• Fenton's reagent MeSH Prohlížeč
• fungální proteiny MeSH
• peroxid vodíku MeSH
• transportní proteiny MeSH
• železo MeSH

The rate of hexose transport was approximately 60% lower for both the high- and the low-affinity components of hexose uptake when a glucose-6-phosphate isomerase mutant of Saccharomyces cerevisiae was preincubated with glucose, as compared with preincubation with water. Similarly the Jmax value of the high-affinity system of the mutant was 25-35% of the corresponding Jmax value for normal cells incubated with glucose. Accumulation of glucose 6-phosphate or of some other metabolite, such as fructose 6-phosphate or trehalose, may be responsible for this striking inhibition.

• MeSH
• aktivní transport účinky léků   MeSH
• glukosa-6-fosfátisomerasa genetika   metabolismus   MeSH
• glukosa farmakologie   MeSH
• hexosy farmakokinetika   MeSH
• kinetika MeSH
• mutace MeSH
• Saccharomyces cerevisiae genetika   metabolismus   MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• glukosa-6-fosfátisomerasa MeSH
• glukosa MeSH
• hexosy MeSH