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Although much research has been performed on DNA complexes carrying long alkyl chains (C10, C16, and C18), there is no information about physicochemical characterization of synthesized composites with allyl imidazole-based ionic liquids and quaternary ammonium salts with n-butyl chains. Here, complexes were synthesized by ion-exchange reactions between sonicated DNA and three ionic liquids (ILs) formed from two imidazole-based compounds, 1-allyl-3-methylimidazolium bromide (Amim) or 1-butyl-3-methylimidazolium bromide (Bmim), and from the quaternary ammonium salt tetra-n-butylammonium bromide (TBAB). Signals in UV-Vis, IR, and CD spectra indicating inclusion of small molecules into the DNA structure confirmed the formation of DNA complexes. Both IR and CD spectra indicated that the B-form conformation of the DNA did not change after the formation of the complexes. Similarly, X-ray diffraction patterns revealed that the formation of IL-DNA complexes did not change the structure of native B-form DNA. Molecular weight (M w) and radii of gyration (R g) values of IL-DNA complex chains, established by high-performance size exclusion chromatography coupled with multiangle-laser light-scattering with a differential refractive index detector, were significantly lower than those values found for native DNA molecules due to DNA fragmentation by sonication during complex formation and the direct effects of the IL on the DNA. Scanning electron microscopy images indicate the formation of nanofibres in DNA-Amim and DNA-Bmim complexes, whereas the formation of nanowires was found in samples of DNA-TBAB complexes. Changes in optical properties confirmed by UV and photoluminescence make DNA-IL complexes potential candidates for biosensor application.

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The impact of the illumination with white linearly polarized light (WLPL) of two commercially available cellulases from Trichoderma reesei on their activity in hydrolysis of microcrystalline cellulose was studied. Enzymes were illuminated with WLPL for 60 min and 120 min and for each native and illuminated enzyme sample specific activity and kinetics of enzyme catalyzed hydrolysis of microcrystalline cellulose were established. Molecular weight M w and radii if gyration R g of protein chains of native and illuminated enzymes were measured by means of high pressure size exclusion chromatography coupled with multiangle laser light scattering and refractometric detectors (HPSEC-MALLS-RI). Conformations of protein chains of native and illuminated enzymes were evaluated on the basis of their circular dichroism (CD) spectra. Additionally, molecular weight M w and radii of gyration R g of polysaccharide chains of microcrystalline cellulose native and digested for 10 min, 480 min and 1440 min with original and WLPL stimulated enzymes WT and TR were taken. Illumination with WLPL of both cellulases studied did not change secondary structures of protein molecules of native enzyme. Molecular weight M w and radii of gyration R g of illuminated enzymes differed greatly from those found for native enzymes. Illumination of enzymes led to increase of specific activity and rate constants of reaction of hydrolysis microcrystalline cellulose catalyzed by illuminated enzymes as compared with native enzymes.

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Scope: Aqueous suspensions of spelt and wheat starch were irradiated with ultraviolet radiation for 5–50 h. The changes in the molecular structure of the starch induced by UV radiation were related to the photodegradation of starch chains and the subsequent recombination of the resulting polysaccharide radicals during prolonged irradiation. Methods and Results: Aqueous suspensions of spelt and wheat starch were irradiated with ultraviolet radiation for 5–50 h. The HPSEC-MALLS-RI method was used to measure the weight-average molecular weights of the starch polysaccharide chains and the distribution of the amylopectin side chains. FTIR spectroscopy of the modified samples and a study of the starch surface morphology were conducted using a scanning electron microscope. However, an increase in both the rate constant of the first stage of hydrolysis (k1) and its final level were demonstrated. The changes in the molecular structure of the starch induced by UV radiation were related to the photodegradation of starch chains and the subsequent recombination of the resulting polysaccharide radicals during prolonged irradiation. Conclusions: Changes in starch granules could influence some of their functional properties. Rearrangement in the polysaccharide chains could obtain novel starches with defined properties.

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