Fluidity
Dotaz
Zobrazit nápovědu
Experimental biology and medicine
xii, 445 s. : il., tab. ; 24 cm
- MeSH
- biologie buňky MeSH
- buněčná membrána fyziologie MeSH
- fluidita membrány genetika MeSH
- lipidy fyziologie MeSH
- membránové lipidy fyziologie MeSH
- tekutiny a sekrety tělesné fyziologie MeSH
- Publikační typ
- kongresy MeSH
- souborné dílo MeSH
- Konspekt
- Buněčná biologie. Cytologie
- NLK Obory
- cytologie, klinická cytologie
- biochemie
- biologie
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
Membrane fluidity adaptation to the low growth temperature in Bacillus subtilis involves two distinct mechanisms: (1) long-term adaptation accomplished by increasing the ratio of anteiso- to iso-branched fatty acids and (2) rapid desaturation of fatty acid chains in existing phospholipids by induction of fatty acid desaturase after cold shock. In this work we studied the effect of medium composition on cold adaptation of membrane fluidity. Bacillus subtilis was cultivated at optimum (40 degrees C) and low (20 degrees C) temperatures in complex medium with glucose or in mineral medium with either glucose or glycerol. Cold adaptation was characterized by fatty acid analysis and by measuring the midpoint of phospholipid phase transition T(m) (differential scanning calorimetry) and membrane fluidity (DPH fluorescence polarization). Cells cultured and measured at 40 degrees C displayed the same membrane fluidity in all three media despite a markedly different fatty acid composition. The T(m) was surprisingly the highest in the case of a culture grown in complex medium. On the contrary, cultivation at 20 degrees C in the complex medium gave rise to the highest membrane fluidity with concomitant decrease of T(m) by 10.5 degrees C. In mineral media at 20 degrees C the corresponding changes of T(m) were almost negligible. After a temperature shift from 40 to 20 degrees C, the cultures from all three media displayed the same adaptive induction of fatty acid desaturase despite their different membrane fluidity values immediately after cold shock.
Introduction of microfluidic mixing technique opens a new door for preparation of the liposomes and lipid-based nanoparticles by on-chip technologies that are applicable in a laboratory and industrial scale. This study demonstrates the role of phospholipid bilayer fragment as the key intermediate in the mechanism of liposome formation by microfluidic mixing in the channel with "herring-bone" geometry used with the instrument NanoAssemblr. The fluidity of the lipid bilayer expressed as fluorescence anisotropy of the probe N,N,N-Trimethyl-4-(6-phenyl-1,3,5-hexatrien-1-yl) was found to be the basic parameter affecting the final size of formed liposomes prepared by microfluidic mixing of an ethanol solution of lipids and water phase. Both saturated and unsaturated lipids together with various content of cholesterol were used for liposome preparation and it was demonstrated, that an increase in fluidity results in a decrease of liposome size as analyzed by DLS. Gadolinium chelating lipids were used to visualize the fine structure of liposomes and bilayer fragments by CryoTEM. Experimental data and theoretical calculations are in good accordance with the theory of lipid disc micelle vesiculation.
- MeSH
- biokompatibilní materiály metabolismus MeSH
- cholestyraminová pryskyřice metabolismus MeSH
- fluidita membrány * MeSH
- fluorescenční polarizace MeSH
- laboratoř na čipu MeSH
- liposomy chemická syntéza MeSH
- mikrofluidika přístrojové vybavení metody MeSH
- nanostruktury * MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Although plants are exposed to a great number of pathogens, they usually defend themselves by triggering mechanisms able to limit disease development. Alongside signalling events common to most such incompatible interactions, modifications of plasma membrane (PM) physical properties could be new players in the cell transduction cascade. Different pairs of elicitors (cryptogein, oligogalacturonides, and flagellin) and plant cells (tobacco and Arabidopsis) were used to address the issue of possible modifications of plant PM biophysical properties induced by elicitors and their links to other events of the defence signalling cascade. We observed an increase of PM order whatever the elicitor/plant cell pair used, provided that a signalling cascade was induced. Such membrane modification is dependent on the NADPH oxidase-mediated reactive oxygen species production. Moreover, cryptogein, which is the sole elicitor able to trap sterols, is also the only one able to trigger an increase in PM fluidity. The use of cryptogein variants with altered sterol-binding properties confirms the strong correlation between sterol removal from the PM and PM fluidity enhancement. These results propose PM dynamics as a player in early signalling processes triggered by elicitors of plant defence.
- MeSH
- Arabidopsis fyziologie MeSH
- buněčná membrána metabolismus fyziologie MeSH
- fluidita membrány fyziologie MeSH
- fluorescenční mikroskopie MeSH
- fluorescenční spektrometrie MeSH
- konfokální mikroskopie MeSH
- nemoci rostlin MeSH
- odolnost vůči nemocem fyziologie MeSH
- reaktivní formy kyslíku metabolismus MeSH
- signální transdukce fyziologie MeSH
- tabák fyziologie MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- MeSH
- diabetes mellitus MeSH
- erytrocytární membrána MeSH
- fluidita membrány MeSH
- glykosylace MeSH
- inzulin MeSH
- kaptopril MeSH
- lidé MeSH
- penicilamin MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- srovnávací studie MeSH
- MeSH
- anizotropie MeSH
- fluidita membrány účinky záření MeSH
- fluorescence MeSH
- jaterní mitochondrie fyziologie účinky léků MeSH
- krysa rodu rattus MeSH
- regenerace jater fyziologie účinky léků MeSH
- trijodthyronin farmakologie MeSH
- zvířata MeSH
- Check Tag
- krysa rodu rattus MeSH
- zvířata MeSH
- Publikační typ
- srovnávací studie MeSH
