ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Journal of bioenergetics and biomembranes 21 (1989), S. 77-91 
    ISSN: 1573-6881
    Keywords: Phase transitions ; phospholipids ; water ; desiccation ; dehydration ; anhydrobiosis ; imbibition
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Physics
    Notes: Abstract Dry phospholipid bilayers are known to undergo transient changes in permeability during rehydration. In this review, we present evidence from which we suggest that this permeability change is due to a gel to liquid-crystaline phase transition accompanying rehydration. If the transition is avoided, as in lipids that remain in gel phase whether dry or rehydrated, the problem of leakage during rehydration is obviated, at least in part. Further, the evidence that the transition temperature for dry bilayers can be depressed by certain sugars is discussed. Finally, we show that these principles can be extended to intact cells. Using pollen grains as a model, we have measured the transition temperature for membrane phospholipids and show that the transition is correlated with physiological measurements including permeability changes and subsequent germination. From theT m values taken from pollen grains at different water contents, we have constructed a phase diagram for the intact pollen that has high predictive value for physiological properties.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 2
    ISSN: 1573-5176
    Keywords: Cyanobacteria ; Nostoc commune ; glycan ; phase transition ; membrane ; desiccation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Cells of the cyanobacterium Nostoc commune secrete a complex, high molecular weight, extracellular polysaccharide (EPS) which accumulates to more than 60% of the dry weight of colonies. The EPS was purified from the clonal isolate N. commune DRH1. The midpoint of the membrane phase transition (Tm) of desiccated cells of N. commune CHEN was low (Tm dry = 8 °C) and was comparable to the Tm of rehydrated cells((Tm)H20 = 6 °C). The EPS was not responsible for the depression of Tm. However, the EPS, at low concentrations, inhibited specifically the fusion of phosphatidylcholine membrane vesicles when they were dried in vitro at0% relative humidity (−400 MPa). Low concentrations of a trehalose:sucrose mixture, in a molar ratio which corresponded with that present in cells in vivo, together with small amounts of the EPS, were efficient in preventing leakage of carboxyfloroscein (CF) from membrane vesicles. Freeze-fracture electron microscopy resolved complex changes in the structure of the EPS and the outer membrane in response to rehydration of desiccated cells. The capacity of the EPS to prevent membrane fusion, the maintenance of a low Tm dry in desiccated cells, and the changes in rheological properties of the EPS in response to water availability, constitute what are likely important mechanisms for desiccation tolerance in this cyanobacterium.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...