Browsing by Subject "immunocytochemistry"

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    ASP53, a thermostable protein from Acacia erioloba seeds that protects target proteins against thermal denaturation.
    (CSIRO Publishing, 2007) Mtwisha, Linda; Farrant, Jill M; Brandt, Wolf; Hlongwane, Caswell; Lindsey, George G
    ASP53, a 53 kDa heat soluble protein, was identified as the most abundant protein in the mature seeds of Acacia erioloba E.Mey. Immunocytochemistry showed that ASP53 was present in the vacuoles and cell walls of the axes and cotyledons of mature seeds and disappeared coincident with loss of desiccation tolerance. The sequence of the ASP53 transcript was determined and found to be homologous to the double cupin domain-containing vicilin class of seed storage proteins. Mature seeds survived heating to 60◦C and this may be facilitated by the presence of ASP53. Circular dichroism spectroscopy demonstrated that the protein displayed defined secondary structure, which was maintained even at high temperature. ASP53 was found to inhibit all three stages of protein thermal denaturation. ASP53 decreased the rate of loss of alcohol dehydrogenase activity at 55◦C, decreased the rate of temperature-dependent loss of secondary structure of haemoglobin and completely inhibited the temperature-dependent aggregation of egg white protein.
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    Cell wall characteristics and structure of hydrated and dry leaves of the resurrection plant Craterostigma wilmsii, a microscopical study.
    (Elsevier, 1999) Vicré, M; Sherwin, H W; Driouich, A; Jaffer, M A; Farrant, J M
    The cell wall architecture of leaf tissues of the resurrection plant Craterostigma wilmsii at various stages of dehydration and rehydration was studied using electron microscopy and immunocytochemistry with antibodies to a hemicellulose (xyloglucan) and pectins. Upon dehydration, the cell walls were shown to fold extensively. It is thought that this folding may prevent excessive mechanical stress developing between the cell wall and the plasmalemma. Our immunocytochemical results show a significant increase in labelling of xyloglucan and unesterified pectins in the cell wall during drying, with levels declining again during rehydration. These components are known to play an important structural role within the cell wall, giving it more tensile strength. It is hypothesised that this increase in tensile strength allows the cell wall to contract and then fold as the plant dries and ultimately prevents the total inward collapse of the cell walls in dry tissue. The increased tensile strength may also be necessary to prevent the cell wall from unfolding and expanding too rapidly upon rehydration, thus allowing plasmalemma-cell wall connections to be reestablished.