Cross synergism

If the mechanism of cellulase action can be explained simply in terms of sequential action of endo- and exoglucanases, it is logical to expect that Ci from one cellulase preparation should act synergistically with Cx from another, at least in those enzyme systems from which both Cx and Ci have been isolated. Synergism between Ci of P. funiculosum and Cx of T. viride has already been demonstrated (22), and the results in Table V show that "cross-synergism of this type is shown by many different mixtures of the Ci and Cx components of F. solani, T, koningii, and P. funiculosum cellulases. In each case, a marked potentiation in activity is observed. 

Certain cellulolytic fungi yield cell-free filtrates capable of extensive degradation of highly ordered forms of cellu-losic material. These filtrates have been shoum to contain a so-called Cj-component, which, although essential for this type of activity, is virtually without action when freed from the other (Cx) components. Crcomponents, with very similar properties, have been isolated from Trichoderma viride and from Penicillium funiculosum. The powerful synergistic action on cotton previously found between the Ct and Cx components of T. viride was also displayed by those from P. funiculosum cross-synergism has also been demonstrated. An attempt has been made to explain the role of Ct in the solubilization of cotton. 

The Ci- and Cx-components from T. viride and P. funiculosum also exhibited cross-synergism for example the Ci- from P. funiculosum could act almost as effectively on cotton in synergism with the Cx from T. viride as with its own Cx (Figure 7). This Ci-preparation has been used to confer the ability to solubilize highly ordered forms of cellulose on certain cellulase preparations, which, although apparently deficient in Ci-component, contain other useful polysaccharases. 

Figure 7. Cross synergism of the Crcompo nent of P. funiculosum cellulose with its own Cx-component and with the Cx-component of T. viride cellulose. A relative concentration of 1.0 is here used to express the concentration of components that, when recombined, produce a solubilization equivalent to that caused by a culture filtrate from P. funiculosum diluted three fold...

The understanding of bio- and chemo-catalytic functionalities, their integration in recognizing materials (doped materials, membranes, tubes, conductive materials, biomarker detection, etc.) and the development of smart composite materials (e.g., bio-polymer-metal) are all necessary elements to reach above objectives. It is thus necessary to create the conditions to realize a cross-fertilization between scientific areas such as catalysis, membrane technology, biotech materials, porous solids, nanocomposites, etc., which so far have had limited interaction. Synergic interactions are the key factor to realizing the advanced nanoengineered devices cited above. 

The 27 papers in this volume present a cross section of synthesis, characterization, and chemical studies by academic and industrial researchers. Although zeolite research activity has been predominantly industrially based, increasing effort and results are now emanating in academic laboratories. The synergism and mutual stimulation of these efforts can be expected to increase the quality and quantity of current and future research involving microporous crystalline molecular sieves. 

Achayuthakan et al. (2006) studied vane yield stress of Xanthan gum-stareh dispersions. The intrinsic viscosity of Xanthan gum was determined to be 112.3 dl/g in distilled water at 25°C. In addition, the size of the granules in the dispersions of the studied starches waxy maize (WXM), cross-linked waxy maize (CWM), and cold water swelling (CWS) were determined. The values of yield stress of the starch-xanthan dispersions relative to those of the starch-water dispersions (YSA"S0) and relative mean granule diameters (D/DO) plotted against values of c[ ] of xanthan gum are shown in Figure 4-42. With the values of YS/YSO being less than 1.0, there was no synergism between CLWM starch and xanthan gum. 

Alcohol-dependent people with a physical tolerance are relatively tolerant of some other cerebral depressant drugs (hydrocarbon anaesthetics), but of course the synergism with these drugs still occurs. There is no significant acquired cross-tolerance with opioids. 

Chimowitz and coworkers [9,10] emphasized the synergism caused by the cross exponential terms exp(—XiA 23) on the entrainer effect, and Jonah and Cochran [12] related the coefficients Ka to the limiting values of the Kirkwood-Buff (KB) integrals and used the conformal solution theory to discuss the entrainer effect. 

At tin, F.l. and Freeker, T. (1984). Cross-resistance spectrum and synergism studies in organophosphorus-resistant strains of Oryztiephilus sttrinamensis (I,.) (C oleoptera Cucujidae) in Australia. J. Rootj. Erilonicr . 77. 1367-[370. 

In considering whether MFO-catalyzed metabolism of herbicides is associated with cross-resistance in Lolium rigidum we have taken, initially, an indirect approach. Growth experiments with wheat showed that the MFO inhibitors aminobenzotriazole (ABT) and PBO synergized chlortoluron when the herbicide and inhibitors were added as a soil drench (34). This synergism was presumed to be due to the inhibition of MFO-catalysed metabolism of chlortoluron (27-29). Significantly, Kemp and Caseley (2) have shown that cross-resistant Alopecurus are relatively more susceptible to chlortoluron in the presence of ABT and other... 

The mixed-function oxidase inhibitors aminobenzotriazole and piperonyl butoxide can synergize herbicide activity in resistant Lolium growing in a hydroponic system. This indicates that at least one aspect of cross-resistance in Lolium rigidum may be related to enhanced metabolic activity of mixed-function oxidazes acting to detoxify herbicides. We are now concentrating on direct studies of herbicide metabolism in resistant biotypes. 

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