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
    [s.l.] : Nature America Inc.
    Nature biotechnology 18 (2000), S. 145-146 
    ISSN: 1546-1696
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: [Auszug] Preservation of cells by freezing or drying is of enormous practical importance in industry, clinical medicine, and agriculture. Two new reports in this issue present results showing that the sugar, trehalose, can preserve frozen or dry mammalian cells, findings that are likely to find immediate ...
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 2
    ISSN: 1399-3054
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: In previous studies on the causes of imbibitional leakage in dry polien we have presented data which suggest that the leakage is due to a gel to liquid crystalline phase transition in membrane phospholipids during the rehydration event. In the present study we greatly extend and confirm those results. A supplemented phase diagram for the hydration dependent transition temperature of membrane phospholipids in pollen is presented. In pollen containing 〉 0.05 g H2O g−1 dry weight at the time of imbibition, this phase diagram for the phospholipids precisely predicts the conditions for rehydration under which germination is maximal and leakage is minimal. However, in extremely dry pollen, containing 〈 0.05 g H2O g−1 dry weight the predictive value of the phase diagram for phospholipids in the pollen is not in agreement with data for germination and leakage. Thus, an alternative explanation must be sought for leakage in these circumstances. We examined the available evidence and suggest here that a modified form of the non-bilayer phase hypothesis proposed by Simon (1974) may apply in the specialized case of extremely dry cells.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 3
    facet.materialart.
    Unknown
    In:  CASI
    Publication Date: 2013-08-31
    Description: Anhydrobiosis, or life without water is commonly demonstrated by a number of plants and animals. These organisms have the capacity to loose all body water, remain dry for various periods, and then be revived by rehydration. While in the anhydrobiotic state, these organisms become highly resistant to several environmental stresses such as extremely low temperatures, elevated temperatures, ionizing radiation, and high vacuum. Since water is commonly thought to be essential for life, survival of anhydrobiotic organisms with an almost total loss of water is examined. A search of literature reveal that many anhydrobiotic organisms make large quantities of trehalose or other carbohydrates. Laboratory experiments have shown that trehalose is able to stabilize and preserve microsomes of sarcoplasmic reticulum and artificial liposomes. It was demonstrated that trehalose and other disaccharides can interact directly with phosopipid headgroups and maintain membranes in their native configuration by replacing water in the headgroup region. Recent studies show that trehalose is an effective stabilizer of proteins during drying and that it does so by direct interaction with groups on the protein. If life that is able to withstand environmental extremes has ever developed on Mars, it is expected that such life would have developed some protective compounds which can stabilize macromolecular structure in the absence of water and at cold temperatures. On Earth, that role appears to be filled by carbohydrates that can stabilize both membrane and protein stuctures during freezing and drying. By analog with terrestrial systems, such life forms might develop resistance either during some reproductive stage or at any time during adult existence. If the resistant form is a developmental stage, the life cycle of the organism must be completed with a reasonable time period relative to time when environmental conditions are favorable. This would suggest that simple organisms with a short life cycle might be most sucessful.
    Keywords: LIFE SCIENCES (GENERAL)
    Type: NASA, Ames Research Center, Exobiology and Future Mars Missions; p 13-14
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 4
    ISSN: 1520-4995
    Source: ACS Legacy Archives
    Topics: Biology , Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 5
    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 ...
  • 6
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Biologie in unserer Zeit 22 (1992), S. 28-32 
    ISSN: 0045-205X
    Keywords: Life and Medical Sciences
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 7
    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 ...
  • 8
    Electronic Resource
    Electronic Resource
    Palo Alto, Calif. : Annual Reviews
    Annual Review of Physiology 60 (1998), S. 73-103 
    ISSN: 0066-4278
    Source: Annual Reviews Electronic Back Volume Collection 1932-2001ff
    Topics: Medicine , Biology
    Notes: Abstract Numerous organisms are capable of surviving more or less complete dehydration. A common feature in their biochemistry is that they accumulate large amounts of disaccharides, the most common of which are sucrose and trehalose. Over the past 20 years, we have provided evidence that these sugars stabilize membranes and proteins in the dry state, most likely by hydrogen bonding to polar residues in the dry macromolecular assemblages. This direct interaction results in maintenance of dry proteins and membranes in a physical state similar to that seen in the presence of excess water. An alternative viewpoint has been proposed, based on the fact that both sucrose and trehalose form glasses in the dry state. It has been suggested that glass formation (vitrification) is in itself sufficient to stabilize dry biomaterials. In this review we present evidence that, although vitrification is indeed required, it is not in itself sufficient. Instead, both direct interaction and vitrification are required. Special properties have often been claimed for trehalose in this regard. In fact, trehalose has been shown by many workers to be remarkably (and sometimes uniquely) effective in stabilizing dry or frozen biomolecules, cells, and tissues. Others have not observed any such special properties. We review evidence here showing that trehalose has a remarkably high glass-transition temperature (Tg). It is not anomalous in this regard because it lies at the end of a continuum of sugars with increasing Tg. However, it is unusual in that addition of small amounts of water does not depress Tg, as in other sugars. Instead, a dihydrate crystal of trehalose forms, thereby shielding the remaining glassy trehalose from effects of the added water. Thus under less than ideal conditions such as high humidity and temperature, trehalose does indeed have special properties, which may explain the stability and longevity of anhydrobiotes that contain it. Further, it makes this sugar useful in stabilization of biomolecules of use in human welfare.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 9
    Electronic Resource
    Electronic Resource
    s.l. : American Chemical Society
    Biochemistry 28 (1989), S. 3916-3922 
    ISSN: 1520-4995
    Source: ACS Legacy Archives
    Topics: Biology , Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 10
    Publication Date: 1992-01-01
    Print ISSN: 0273-1177
    Electronic ISSN: 1879-1948
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Published by Elsevier
    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...