Physicochemical characterisation of kafirins extracted from sorghum grain and dried distillers grain with solubles related to their biomaterial functionality

Kafirin, the hydrophobic prolamin storage protein in sorghum grain is enriched when the grain is used for bioethanol production to give dried distillers grain with solubles (DGGS) as a by-product. There is great interest in DDGS kafirin as a new source for biomaterials. There is however a lack of fundamental understanding of how the physicochemical properties of DDGS kafirin having been exposed to the high temperature conditions during ethanol production, compare to kafirin made directly from the grain. An understanding of these properties is required to catalyse the utilisation of DDGS kafirin for biomaterial applications. The aim of this study was to extract kafirin directly from sorghum grain and from DDGS derived from the same grain and, then perform a comparative investigation of the physicochemical properties of these kafirins in terms of: polypeptide profile by sodium-dodecyl sulphate polyacrylamide gel electrophoresis; secondary structure by Fourier transform infra-red spectroscopy and x-ray diffraction, self-assembly behaviour by small-angle x-ray scattering, surface morphology by scanning electron microscopy and surface chemical properties by energy dispersive x-ray spectroscopy. DDGS kafirin was found to have very similar polypeptide profile as grain kafirin but contained altered secondary structure with increased levels of β-sheets. The structure morphology showed surface fractals and surface elemental composition suggesting enhanced reactivity with possibility to endow interfacial wettability. These properties of DDGS kafirin may provide it with unique functionality and thus open up opportunities for it to be used as a novel food grade biomaterial.

Effect of Phytase Addition to Buckwheat Wort on the Selected Fermentable Sugars, Polypeptide Profile and Nitrogen Content from Free Aminoacids

Relatively high levels of phytates in buckwheat malt and the low activity of endogenous phytases that limit the effective use of substrates for fermentation and yeast metabolism (starch, proteins, minerals) are an argument for using phytases in beer production technology. Two mash-in programs were applied: (1) the Congress program, typical for basic raw materials, (2) a program with temperature optimized for phytase activity. Commercial preparations of 3-phytase (Finase P) and 6-phytase (Ronozyme) were used in the study. Monitored levels of selected fermentable sugars indicates a statistically significant effect of phytase addition on the glucose content in both mash-in programs used. The SEC-HPLC chromatography allowed to select a key polypeptide with an estimated molecular weight of 40 kDa, whose relative peak area decreases as a result of the applied mash-increase treatment with phosphorolytic enzymes, although this relation was not statistically confirmed in the analysis of free amino acids content. The analyses carried out also indicate that apart from the target molecules, namely phytate and inositol, the use of phytases in the process of buckwheat wort preparation slightly changes the profile of fermentable sugars and causes significant changes in the polypeptide profile of the final mash.

Physicochemical characterisation of kafirins extracted from sorghum grain and dried distillers grain with solubles related to their biomaterial functionality

Kafirin, the hydrophobic prolamin storage protein in sorghum grain is enriched when the grain is used for bioethanol production to give dried distillers grain with solubles (DGGS) as a by-product. There is great interest in DDGS kafirin as a new source for biomaterials. There is however a lack of fundamental understanding of how the physicochemical properties of DDGS kafirin having been exposed to the high temperature conditions during ethanol production, compare to kafirin made directly form the grain. An understanding of these properties is required to catalyse the utilisation of DDGS kafirin for biomaterial applications. The aim of this study was to extract kafirin directly from sorghum grain and from DDGS derived from the same grain and, then perform a comparative investigation of the physicochemical properties of these kafirins in terms of: polypeptide profile by sodium-dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE); secondary structure by Fourier transform infra-red (FTIR) spectroscopy and x-ray diffraction (XRD), self-assembly behaviour by small-angle x-ray scattering (SAXS), surface morphology by scanning electron microscopy (SEM) and surface chemical properties by energy dispersive x-ray spectroscopy (EDS). DDGS kafirin was found to have very similar polypeptide profile as grain kafirin but contained altered secondary structure with increased levels of β-sheets. The structure morphology showed surface fractals and surface elemental composition suggests enhanced reactivity with possibility to endow interfacial wettability. These properties of DDGS kafirin may provide it with unique functionality and thus open up opportunities for it to be used as a novel food grade biomaterial.

The effect of cryoprotective agents on proteins of the erythrocyte membrane-cytoskeleton complex

The aim of the study was to evaluate of the effects of glycerol and DMSO, belonging to the endocellular type of cryoprotective agents (CPAs), as well as polyethylene glycol, dextran, sucrose, and mannitol, related to exocellular CPAs, on proteins of the membrane-cytoskeleton complex (MCC) of human erythrocytes at the stage preceding freezing. The assessment of protein modifications was performed by SDS-PAGE using different approaches when preparing samples for analysis. The use of β-mercaptoethanol in the solubilizing buffer showed no changes in the MCC polypeptide profile of erythrocytes preincubated with CPAs thus suggesting good biocompatibility of the studied substances. The use of the cross-linking reagent diamide for assessment of protein modifications did not reveal structural abnormalities that would result in significant changes in the localization of −SH groups and an increase in the production of high-molecular-weight polypeptide complexes identified by SDS-PAGE without β-mercaptoethanol. However, the recognized changes in the electrophoretic mobility of proteins in the area of band 5 in erythrocytes incubated with CPA in the presence of diamide suggest a reorganization of the structural state of actin protofilaments, which can be caused by alterations of actin monomers themselves or initiated by modifications of actin-binding proteins in the presence of CPAs. In addition, an increase in the amount of the protein fraction located between bands 5 and 6 in the MCC profiles of erythrocytes incubated with CPA and diamide was revealed. Despite the similarity of the reaction of erythrocyte proteins to different CPAs, the properties of cells depending on MCC, may differ due to modifications in the macromolecule structures, which are not associated with changes in the localization of the −SH-groups of proteins. The results obtained indicate that CPAs may have a significant impact on the erythrocyte MCC, and this requires further research.

COMPARISON OF POLYPEPTIDE PROFILE OF Trypanosoma evansi ISOLATES FROM INDONESIA AND THEIR RELATION TO BIOTYPE AND SENSITIVITY TO TRYPANOCIDAL

This study aimed to determine whether the variant or biotype of Trypanosoma evansi can be seen from their polypeptide profiles using 12%sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS PAGE) stained with Brilliant Blue Commasie. The results generally showed thatthe molecular weight (MW) of polypeptides from nine isolates from East Java, Central Java, Banten, South Kalimantan, Central Kalimantan, andLampung provinces were in the range of 85.46 to 15.76 kD and each isolate has different polypeptide profile. Isolates A13 and A14 were isolatedfrom the same place but have different polypeptide profiles. Likewise, isolates S13 and S18 also have different polypeptide profiles despite beingisolated from the same place at the same time. On the other hand, isolate 372, 87, and 06 have different protein profiles but was classified in thesame biotype namely biotype I. Generally, the difference in protein profile actually more related to the biological diversity of the metabolism ofeach Trypanosoma evansi isolate from Indonesia.

Nuclear Sm antigens in the sperm of different organisms

SummaryImmunoblot analysis of sperm protein from several species revealed the presence of polypeptides recognised by anti-Sm sera obtained from patients with systemic lupus erythematosus. Immunoreactive polypeptides in human, bull, mouse and rat sperm were identified as protein B', B and D as compared with the Sm polypeptides of HeLa cells. In the sperm of rooster, the teleost fish Cyprinus carpio and the mussel Choromytilus chorus, the immunoreactive polypeptide profile was more complex. To ascertain the sperm origin of the Sm antigens, immunolocalisation with anti-Sm serum was carried out. The results demonstrated that in all the specied studied staining was confinde to the sperm nucleus, confirming that some polypeptides of the small nuclear ribonnucleoprotein complex are present in the gamete.