Induction period defect effect

Next the parent and mutant were compared for their ability to induce cutinase by cutin and hydrolyzed cutin (consisting of small molecular weight inducers) after growth on glucose. As shown in Figure 5, cutinase activity increased over the three-day induction period for both strains in the presence of cutin (Panel A) or hydrolyzed cutin (Panel B) however, cutinase was induced less effectively in the mutant strain, as evidenced by an 80-90% reduction. Hydrolyzed cutin was a 10-fold less effective inducer than cutin in both strains. These data indicated that lack of induction in the mutant was not related to its inability to hydrolyze cutin to small molecular weight inducers. Consequently the defect observed was not related to the inability of the mutant to produce the inducer. 

At early ages, da/d/ increases markedly with w/s ratio above 0.7 (B56). Moderate variations in specific surface area have little effect on the length of the induction period, but with finer grinding, da/d/ during the acceleratory period increases (K20,O12,B56). The rate of reaction increases with temperature up to the end of the acceleratory period, but is much less affected thereafter (K21), suggesting a change from chemical to diffusion control. Introduction of defects into the CjS shortens the induction period (M53,F20,O12). 

In Figure 11.6, the dependences of effective correlation time for initial and cold-rolled mats on ozone oxidation time are represented. The figure shows that for the first hour there is a sharp drop of the i values and then for next 3 hours the decrease of i is very small, that is, the dynamic characteristic is stabilized. After 4 hours of oxidation, the final stage shows the initiation of correlation time decrease. Note that the initial PHB mats and the cold-rolled mats demonstrate the symbatic probe rotation when in accordance with temperature- and water-influence data the mobility of TEMPO in the cold-rolled oxidized mat is decreased relative to the initial mat after ozonolysis. Taking into account the previous characteristics of crystalline structure and ESR data in amorphous area of the PHB and PHBV films after ozone exposition [23], it can be assumed that at the first stage of oxidation the partial destruction of macromolecules occurs that leads to the increase of probe mobility. On this stage only more accessible and defect molecules take part in reaction with ozone which are situated in less dense fields of PHB. After their concentration depletion the PHB-ozone interaction is stabilized for the next 3 hours that could be treated as induction period (the plateau in the Figure 11.6) and than the oxidation... 

---