Browsing by Author "Brandt, W"

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    Inclusion of polyvinylpyrrolidone in the polymerase chain reaction reverses the inhibitory effects of polyphenolic contamination of RNA.
    (Oxford University Press, 1999) Koonjul, P; Brandt, W; Farrant, J; Lindsey, G
    Polysaccharides, secondary metabolites and poly-phenolics are known to co-isolate with nucleic acids from plant tissues resulting in inhibition of molecular manipulations. RNA isolated from the polyphenolic-rich resurrection plant, Myrothamnus flabellifolius, was demonstrated to inhibit a standard polymerase chain reaction used as an assay despite the inclusion of the polyphenolic-binding compound poly(1-vinylpyrrolidone-2) (PVP) into the RNA isolation medium. This inhibition was, however, reversed by the addition of PVP into the PCR mixture itself. Confirmation of the inhibitory effect of polyphenolics on PCR was obtained by addition of green tea polyphenolics to the standard PCR assay. This inhibition was also reversed by the simultaneous inclusion of PVP.
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    Isolation and characterisation of chloroplasts from Myrothamnus flabellifolius Welw.
    (Elsevier, 2000) Koonjul, P; Brandt, W; Lindsey, G; Farrant, J
    Chloroplasts isolated from the resurrection plant Myrothamnus flabellifolius using trehalose gradients had a higher buoyant density than chloroplasts isolated from another resurrection plant Craterostigma wilmsii. The latter had the same buoyant density as those isolated from the desiccation-sensitive (DS) plant Pisum sativum. The increased buoyant density in M. flabellifolius was ascribed to the unusual ultrastructure of the thylakoid membranes. Standard chloroplast isolation protocols resulted in membrane damage in both resurrection plants. Trehalose rather than sucrose gradients were required for isolation of intact chloroplasts. Immunological studies showed that epitopes related to the desiccation stress protein dsp 21 from Craterostigma plantagineum were present in M. flabellifolius. Several small (10–15 kDa) unique stromal proteins were also present. Polyphenolics, including anthocyanins, accumulated in leaves and chloroplasts of M. flabellifolius during drying. Envisaged functions for these are maintenance of membrane integrity, chlorophyll masking and antioxidant protection. Metal (Ca2+, Cu2+, Fe2+, Mg2+ and Mn2+) concentrations declined and thylakoid membranes separated upon drying. We propose that this might be a mechanism to put a stasis on photosynthesis and minimise photo-oxidation damage under water stress conditions.