This study investigated the potential of enzymes to increase soy protein extractability without causing protein degradation. The aqueous extraction of protein was performed from defatted soy flakes on a laboratory-and pilot-plant scale. Yields of protein and reducing sugars were determined in the alkali extracts obtained with cellulases and pectinase, added alone or as cocktails. Using 5% (wt/g of protein) Multifect pectinase resulted in the best improvement of protein yields, which were 50 and 17% greater than the controls in laboratory-and pilot-plant-scale trials, respectively. This enhanced protein extraction was accompanied by an increased reducing sugar content in the aqueous extract compared with the control. Under the conditions tested, no enzyme cocktail markedly increased the protein yield compared with the use of single enzymes. The solubility curve for Multifect pectinase-treated soy protein isolate (SPI) was typical of SPI at pH 2-10. Its foam stability significantly improved, but the emulsification properties declined. Multifect pectinase markedly reduced the viscosity of SPI. SDS-PAGE showed that the α′ and α subunits of β-conglycinin were modified, and glycoprotein staining showed that these modifications were probably due to a protease secondary activity in the pectinase preparation. One cellulase and one pectinase were identified as effective in modifying the protein and reducing sugar extractability from the defatted soy flakes.Paper no. J11184 in JAOCS 83, 71-78 (January 2006).

Pantoea agglomerans CPA-2 is an effective biocontrol agent of postharvest diseases of citrus and pome fruit. A monitoring technique was developed for its identification and to quantify its populations. The methodology used consisted of (i) searching for a semi-selective medium, (ii) identification of molecular markers and (iii) monitoring population dynamics in a commercial trial. As a semi-selective medium, Malonate Broth Agar supplemented with tetracycline hydroxychloride and incubation at high temperature (max. of 40 • C) facilitated the selective recovery of P. agglomerans CPA-2 colonies. The RAPD technique was applied to a collection of 13 strains of P. agglomerans, including CPA-2. Among the 12 primers tested, OPL-11 amplified a fragment (about 720 bp) specific to strain CPA-2. On the basis of this fragment, two SCAR markers were amplified using a primer pair derived from OPL-11 elongation. A first SCAR marker of 720 bp was specifically amplified for the strain CPA-2 and a second one of 270 bp was obtained for all P. agglomerans strains tested, including CPA-2. Commercial trials demonstrated a significant reduction of decay with the treatment of formulated cells of P. agglomerans CPA-2. Population dynamics of CPA-2 in commercial trials were determined on fruit surfaces and in the environment using both the classical plating technique and PCR with SCAR primers. In general, no significant differences were observed between results obtained from the two methods. On fruit surfaces, 1 day after CPA-2 applied its population by classical methods was 4.37 × 10 6 cfu wound −1 and at the end of the experiment the population increased to 5.8 × 10 5 cfu wound −1 . The percentages of colonies identified as P. agglomerans CPA-2 at these sampling times using SCAR primers were 90 and 95%, respectively. Population dynamics in the environment to evaluate the environmental fate of P. agglomerans CPA-2 showed that it has a limited persistence and limited capacity for dispersion.

We assessed the effects of near-lethal heat stress on bud break, heat-shock proteins (HSPs) and ubiquitin in hybrid poplar (Populus nigra (L.) Charkowiensis x P. nigra (L.) incrassata). Shoots, with 10-15 buds each, were collected from September to March and exposed to temperatures between 20 and 60 degrees C for 2 h. Shoots were then placed in a greenhouse at 18-22 degrees C with supplemental light and cumulative bud break was recorded over a 4-week period. Samples of bud tissues were collected during and up to 96 h after heat treatment for protein analysis. De novo synthesis of proteins was monitored by exposing excised buds to [(35)S]-methionine for 3 h before, during, or after heat treatment. Heat treatments of 40-45 degrees C resulted in both a release from endodormancy and a decrease in thermal units needed for bud break during ecodormancy. The response to near-lethal heat stress was complex and was affected by intrinsic thermal sensitivity. Heat treatments were least effective during August and became progressively more effective as endodormancy progressed. In the later stages of ecodormancy, a heat treatment of 45 degrees C either inhibited bud break or killed the buds. Although temperatures of 42.5 to 45 degrees C inhibited incorporation of [(35)S]-methionine into proteins for at least 48 h, several HSPs were synthesized in response to temperatures of 40-45 degrees C. Immunoblots indicated that one of the heat-induced proteins was immunologically related to HSP70. Increases in free and conjugated forms of ubiquitin were also observed in response to heat treatment. Production of HSPs and ubiquitin, however, was not consistently associated with the heat treatments that induced the highest percentage of bud break. The roles of heat-induced protein degradation, HSPs, and ubiquitin in overcoming dormancy by near-lethal heat stress are discussed.

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Sublethal heat stress has been shown to decrease or eliminate deep supercooling of flower buds in woody plants and to release plants from endodormancy. Experiments were conducted to characterize the effect of heat stress on endodormancy and ecodormancy in peach (cv Loring) and two hybrid poplars. Protein synthesis (de novo) and patterns of protein expression were also monitored. In order to determine optimum treatment temperatures, shoots, collected September-March, were exposed to a range of temperatures (35-60 C) under wet or dry conditions for 1-6 h. Shoots were then placed in the greenhouse and cumulative budbreak was monitored over 4 weeks. Samples of bud and bark tissues were collected during and up to 72 h after heat treatment for SDS-PAGE analysis. Data indicate: 1) twigs must be immersed in water for the heat treatments to be effective; 2) heat treatments resulted in a release from endodormancy and a decrease in thermal units needed for budbreak during ecodormancy; 3) 40 C for 2-4 h was optimum in fall and late winter whereas 45 C was the optimum temperature to induce budbreak in midwinter; 4) optimum temperature for peach floral buds (37.5 C/2h) was lower than for vegetative buds (40 C/4h), and 5) heat treatments also decreased cold hardiness. Protein synthesis decreased significantly following heat treatment but was significantly greater than controls (room temp) 24-48 h after heat treatment.