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Annual Progress Report on Malting Barley Research March, 2007

Annual Progress Report on Malting Barley Research March, 2007

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ligated to GenomeWalker (Cl<strong>on</strong>tech Laboratories, Mountain View, CA) adaptors to<br />

produce GenomeWalker libraries. Using gene specific primers, based <strong>on</strong> the 5’<br />

regi<strong>on</strong>s of cDNA sequences and two kinds of GenomeWalker adaptor primers, PCR<br />

amplificati<strong>on</strong>s were performed using general c<strong>on</strong>diti<strong>on</strong>s. PCR products were cl<strong>on</strong>ed<br />

and sequenced. A search for putative cis-acting DNA elements with sequences<br />

homologous to the sequences of the cl<strong>on</strong>ed products was performed using the PLACE<br />

(Plant cis-acting Regulatory DNA Elements) database.<br />

Preparati<strong>on</strong> of peptides and antisera<br />

Synthetic peptides were commercially prepared (Anaspec, Inc., San Jose, CA) to<br />

limited regi<strong>on</strong>s (about 15 amino acids) of deduced amino acid sequences of the four<br />

highly expressed α-glucosidases. We selected <strong>on</strong>e regi<strong>on</strong> of each of the four proteins<br />

that we determined to be unique to that protein and that we predicted to be antigenic<br />

based <strong>on</strong> the extent of it’s hydrophobicity. Synthetic peptides were c<strong>on</strong>jugated with<br />

keyhole limpet hemocyanin then used to produce antibodies specific to the four<br />

isozymes of α-glucosidase from barley. Polycl<strong>on</strong>al antibodies to those c<strong>on</strong>jugated<br />

peptides were produced in rabbits.<br />

Western blots<br />

Crude protein extracts were made from barley tissues using the protocol of<br />

Tibbot et al. (1998). Briefly, the seeds or leaves were ground to a fine powder with<br />

liquid nitrogen in a mortar. Approximately <strong>on</strong>e gram of ground tissue was suspended<br />

in 1 mL of buffer c<strong>on</strong>taining 50 mM Na2CO3/NaHCO3 (pH 9.0), 1 M NaCl, 1% Trit<strong>on</strong>-<br />

X100, 2 mM β-mercaptoethanol and 1% protease inhibitor cocktail for plant extracts<br />

(Sigma, St. Louis, MO, USA). Suspensi<strong>on</strong>s were shaken gently for 1 hr at 4°C. The<br />

homogenates were centrifuged at 12,000xg for 10 min at 4°C. Four mL of 50 mM<br />

sodium succinate buffer (pH 4.5) were added to the supernatants, which were then<br />

dialyzed against the same buffer. After dialysis, extracts were centrifuged again to<br />

obtain samples for Western blot analysis. Proteins in these supernatants were<br />

resolved by SDS-PAGE, transferred to polyvinylidene fluoride membranes and probed<br />

with the rabbit antiserum. Detecti<strong>on</strong> of cross reacting proteins were determined using<br />

118

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