X-Message-Number: 32323
Date: Mon, 18 Jan 2010 23:33:40 -0800 (PST)
From: 
Subject: Vitrification is essential for anhydrobiosis

Proc Natl Acad Sci U S A. 2008 Apr 1;105(13):5093-8. Epub 2008 Mar 24.

Vitrification is essential for anhydrobiosis in an African chironomid, 
Polypedilum vanderplanki.

Sakurai M, Furuki T, Akao K, Tanaka D, Nakahara Y, Kikawada T, Watanabe M, Okuda
T. Center for Biological Resources and Informatics, Tokyo Institute of 
Technology, B-62 Nagatsuta-cho, Midori-ku, Yokohama 226-8501, Japan.

    Anhydrobiosis is an extremely dehydrated state in which organisms show no 
    detectable metabolism but retain the ability to revive after rehydration. 
    Thus far, two hypotheses have been proposed to explain how cells are 
    protected during dehydration: (i) water replacement by compatible solutes 
    and (ii) vitrification. The present study provides direct physiological and 
    physicochemical evidence for these hypotheses in an African chironomid, 
    Polypedilum vanderplanki, which is the largest multicellular animal capable 
    of anhydrobiosis. Differential scanning calorimetry measurements and 
    Fourier-transform infrared (FTIR) analyses indicated that the anhydrobiotic 
    larvae were in a glassy state up to as high as 65 degrees C. Changing from 
    the glassy to the rubbery state by either heating or allowing slight 
    moisture uptake greatly decreased the survival rate of dehydrated larvae. In
    addition, FTIR spectra showed that sugars formed hydrogen bonds with 
    phospholipids and that membranes remained in the liquid-crystalline state in
    the anhydrobiotic larvae. These results indicate that larvae of P. 
    vanderplanki survive extreme dehydration by replacing the normal 
    intracellular medium with a biological glass. When entering anhydrobiosis, 
    P. vanderplanki accumulated nonreducing disaccharide trehalose that was 
    uniformly distributed throughout the dehydrated body by FTIR microscopic 
    mapping image. Therefore, we assume that trehalose plays important roles in 
    water replacement and intracellular glass formation, although other 
    compounds are surely involved in these phenomena.
PMID: 18362351

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