We investigated the effect of Kluyveromyces lactis ERG6 gene deletion on plasma membrane function and showed increased susceptibility of mutant cells to salt stress, cationic drugs and weak organic acids. Contrary to Saccharomyces cerevisiae, Klerg6 mutant cells exhibited increased tolerance to tunicamycin. The content of cell wall polysacharides did not significantly vary between wild-type and mutant cells. Although the expression of the NAD+-dependent glycerol 3-phosphate dehydrogenase (KlGPD1) in the Klerg6 mutant cells was only half of that in the parental strain, it was induced in the presence of calcofluor white. Also, cells exposed to this drug accumulated glycerol. The absence of KlErg6p led to plasma membrane hyperpolarization but had no statistically significant influence on the plasma membrane fluidity. We propose that the phenotype of Klerg6 mutant cells to a large extent was a result of the reduced activity of specific plasma membrane proteins that require proper lipid composition for full activity.
- MeSH
- delece genu MeSH
- fungální proteiny genetika metabolismus MeSH
- fyziologická adaptace * MeSH
- kationické antimikrobiální peptidy metabolismus MeSH
- Kluyveromyces účinky léků enzymologie genetika fyziologie MeSH
- kyseliny karboxylové toxicita MeSH
- methyltransferasy genetika metabolismus MeSH
- osmotický tlak MeSH
- regulace genové exprese u hub * MeSH
- tolerance léku MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Chronic kidney disease (CKD) is associated with increased concentration of intracellular calcium, which is pathological and may lead to irreversible damage of cell functions and structures. The aim of our study was to investigate the impact of 6 months vitamin D(3) supplementation (14 000 IU/week) on free cytosolic calcium concentration ([Ca(2+)](i)) and on the plasma membrane calcium ATPase (PMCA) activity of patients with CKD stage 2-3. PMCA activity of patients was also compared to that of healthy volunteers. Vitamin D(3) supplementation of CKD patients resulted in the decrease of [Ca(2+)](i) (119.79+/-5.87 nmol/l vs. 105.36+/-3.59 nmol/l, n=14, P<0.001), whereas PMCA activity of CKD patients (38.75+/-22.89 nmol P(i)/mg/h) remained unchanged after vitamin D(3) supplementation (40.96+/-17.74 nmol P(i)/mg/h, n=14). PMCA activity of early stage CKD patients before supplementation of vitamin D(3), was reduced by 34 % (42.01+/-20.64 nmol P(i)/mg/h) in comparison to healthy volunteers (63.68+/-20.32 nmol P(i)/mg/h, n=28, P<0.001). These results indicate that vitamin D(3) supplementation had a lowering effect on [Ca(2+)](i) and negligible effect on PMCA activity in CKD patients.
- MeSH
- ATPasy přenášející vápník přes plazmatickou membránu metabolismus MeSH
- cholekalciferol terapeutické užití MeSH
- chronická renální insuficience komplikace enzymologie MeSH
- dospělí MeSH
- lidé středního věku MeSH
- lidé MeSH
- nedostatek vitaminu D enzymologie etiologie prevence a kontrola MeSH
- potravní doplňky MeSH
- senioři MeSH
- studie případů a kontrol MeSH
- vápník metabolismus MeSH
- zdraví dobrovolníci pro lékařské studie MeSH
- Check Tag
- dospělí MeSH
- lidé středního věku MeSH
- lidé MeSH
- senioři MeSH
- Publikační typ
- časopisecké články MeSH
- klinické zkoušky MeSH
- práce podpořená grantem MeSH
Membrane fluidity is a widely recognized biophysical variable that provides information about structural organization of the subcellular membranes exhibiting physical characteristics of liquid crystals. The term “fluidity” reflects in this case the tightness in packing of acyl parts of the membrane phospholipid molecules, a feature that may influence considerably the molecular mobility and via that also the sensitivity and reactivity of membranebound transporters, receptors and enzyme systems. Data presented in this review are aimed to demonstrate the substantial role of changes in membrane fluidity occurring in the processes associated with endogenous protection observed in cardiac sarcolemma and mitochondria in diverse pathologies, particularly in diabetes and hypertension.
- MeSH
- buněčná membrána metabolismus MeSH
- fluidita membrány fyziologie MeSH
- fosfolipidy metabolismus MeSH
- krysa rodu rattus MeSH
- membránové lipidy metabolismus MeSH
- myokard metabolismus MeSH
- sarkolema metabolismus MeSH
- zvířata MeSH
- Check Tag
- krysa rodu rattus MeSH
- zvířata MeSH
- Publikační typ
- přehledy MeSH
Statins, inhibitors of 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase, are effective drugs in the treatment of hypercholesterolemia, however, their undesirable actions are not fully known. We investigated the effects of atorvastatin on the oxidative phosphorylation and membrane fluidity in liver mitochondria, and also on the coenzyme Q (CoQ) content in the mitochondria, liver tissue, and plasma of rats on a standard (C) and hypercholesterolemic (HCh) diet. Atorvastatin was administered at either low (10 mg⋅kg-1) or high dose (80 mg⋅kg-1) for four weeks. The high dose of the drug decreased the concentrations of total cholesterol and triacylglycerols in the plasma and liver of rats on a HCh diet. Administration of atorvastatin was associated with decreased oxygen uptake (state 3), and oxidative phosphorylation rate in the mitochondria of both C and HCh rats. Further, the drug influenced mitochondrial membrane fluidity and dose-dependently reduced concentrations of oxidized and reduced forms of CoQ in the mitochondria. Our findings point to an association between in vivo administration of atorvastatin and impaired bioenergetics in the liver mitochondria of rats, regardless of diet, in conjunction with simultaneous depletion of oxidized and reduced CoQ forms from the mitochondria. This fact may play a significant role in the development of statin-induced hepatopathy.
- MeSH
- cholesterol farmakologie MeSH
- dieta MeSH
- hypercholesterolemie metabolismus MeSH
- jaterní mitochondrie metabolismus MeSH
- játra metabolismus MeSH
- krysa rodu rattus MeSH
- kyseliny heptylové aplikace a dávkování terapeutické užití MeSH
- mikroživiny farmakologie metabolismus MeSH
- pyrroly aplikace a dávkování terapeutické užití MeSH
- statiny aplikace a dávkování terapeutické užití MeSH
- ubichinon farmakologie metabolismus MeSH
- zvířata MeSH
- Check Tag
- krysa rodu rattus MeSH
- mužské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- práce podpořená grantem MeSH
The aim of present study was to investigate functional and physical alterations in membranes of heart mitochondria that are associated with remodeling of these organelles in acute phase of streptozotocin-induced diabetes and to elucidate the role of these changes in adaptation of the heart to acute streptozotocin-induced diabetes (evaluated 8 days after single dose streptozotocin application to male Wistar rats). Action of free radicals on the respiratory chain of diabetic-heart mitochondria was manifested by 17 % increase (p<0.05) in oxidized form of the coenzyme Q(10) and resulted in a decrease of states S3 and S4 respiration, the respiratory control index, rate of phosphorylation (all p<0.01) and the mitochondrial transmembrane potential (p<0.05), but the ADP/O ratio decreased only moderately (p>0.05). On the contrary, membrane fluidity and the total mitochondrial Mg2+-ATPase activity increased (both p<0.05). In diabetic heart mitochondria, linear regression analysis revealed a reciprocal relationship between the increase in membrane fluidity and decrease in trans-membrane potential (p<0.05, r = 0.67). Changes in membrane fluidity, transmembrane potential, Mg2+-ATPase activity and the almost preserved ADP/O ratio appear as the manifestation of endogenous protective mechanisms participating in the functional remodeling of mitochondria which contributes to adaptation of the heart to diabetes.
- MeSH
- Ca(2+)-Mg(2+)-ATPasa metabolismus MeSH
- experimentální diabetes mellitus metabolismus patofyziologie MeSH
- fluidita membrány MeSH
- fyziologická adaptace MeSH
- krysa rodu rattus MeSH
- membránový potenciál mitochondrií MeSH
- mitochondriální membrány metabolismus MeSH
- myokard enzymologie metabolismus MeSH
- oxidativní fosforylace MeSH
- potkani Wistar MeSH
- srdeční mitochondrie enzymologie metabolismus MeSH
- transport elektronů MeSH
- ubichinon analogy a deriváty metabolismus MeSH
- volné radikály metabolismus MeSH
- zvířata MeSH
- Check Tag
- krysa rodu rattus MeSH
- mužské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
In this study, we report for the first time concurrent measurements of membrane potential and dynamics and respiratory chain activities in rat heart mitochondria, as well as calcium transients in the hearts of rats in an early phase of streptozotocin diabetes, not yet accompanied with diabetes-induced complications. Quantitative relationships among these variables were assessed. The mitochondria from diabetic rats exhibited decreased fluorescence anisotropy values of diphenylhexatriene. This indicates that hydrophobic core of the membranes was more fluid compared with controls (p<0.05). We discuss the changes in fluidity as having been associated with augmented energy transduction through the diabetic membranes. Reduced ratio of JC-1 fluorescence (aggregates to monomers) in the mitochondria from diabetic hearts reflected descendent transmembrane potential. A significant negative association between membrane fluidity and potential in the diabetic group was found (p<0.05; r=0.67). Further, we observed an increase in calcium transient amplitude (CTA) in the diabetic cardiomyocytes (p=0.048). We conclude that some of the calcium-induced regulatory events that dictate fuel selection and capacity for ATP production in diabetic heart occur at the membrane level. Our findings offer new insight into acute diabetes-induced changes in cardiac mitochondria.
- MeSH
- experimentální diabetes mellitus metabolismus patofyziologie MeSH
- financování organizované MeSH
- fluidita membrány MeSH
- kardiomyocyty metabolismus MeSH
- krysa rodu rattus MeSH
- kultivované buňky MeSH
- membránový potenciál mitochondrií MeSH
- mitochondriální membrány fyziologie MeSH
- myokard metabolismus MeSH
- oxidativní fosforylace MeSH
- potkani Wistar MeSH
- spotřeba kyslíku MeSH
- srdce patofyziologie MeSH
- srdeční komory cytologie MeSH
- srdeční mitochondrie fyziologie MeSH
- vápník fyziologie MeSH
- zvířata MeSH
- Check Tag
- krysa rodu rattus MeSH
- mužské pohlaví MeSH
- zvířata MeSH
- MeSH
- erytrocytární membrána enzymologie fyziologie účinky záření MeSH
- erytrocyty fyziologie MeSH
- finanční podpora výzkumu jako téma MeSH
- fotochemoterapie metody využití MeSH
- laserová terapie s nízkou intenzitou světla metody využití MeSH
- lidé MeSH
- pyrimidinony farmakokinetika krev MeSH
- sodíko-draslíková ATPasa fyziologie krev MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- srovnávací studie MeSH
- MeSH
- experimentální diabetes mellitus patofyziologie MeSH
- finanční podpora výzkumu jako téma MeSH
- fluidita membrány genetika MeSH
- krysa rodu rattus MeSH
- sarkolema fyziologie patologie MeSH
- srdeční mitochondrie fyziologie patologie MeSH
- zvířata MeSH
- Check Tag
- krysa rodu rattus MeSH
- zvířata MeSH
- Publikační typ
- kongresy MeSH
