Cytoprotective and Cytotoxic Effects of Rice Bran Extracts in Rat H9c2(2-1) Cardiomyocytes

This study was aimed at preliminarily assessing the cytoprotective and antioxidative effects of rice bran extracts (RBEs) from a Sarawak local rice variety (local name: “BJLN”) and a commercial rice variety, “MR219,” on oxidative stress in rat H9c2(2-1) cardiomyocytes. The cardiomyocytes were incubated with different concentrations of RBE and hydrogen peroxide (H2O2), respectively, to identify their respective IC50 values and safe dose ranges. Two nonlethal and close-to-IC50 doses of RBE were selected to evaluate their respective effects on H2O2 induced oxidative stress in cardiomyocytes. Both RBEs showed dose-dependent cytotoxicity effects on cardiomyocytes. H2O2 induction of cardiomyocytes pretreated with RBE further revealed the dose-dependent cytoprotective and antioxidative effects of RBE via an increase in IC50 values of H2O2. Preliminary analyses of induction effects of RBE and H2O2 on cellular antioxidant enzyme, catalase (CAT), also revealed their potential in regulating these activities and expression profile of related gene on oxidative stress in cardiomyocytes. Pretreated cardiomyocytes significantly upregulated the enzymatic activity and expression level of CAT under the exposure of H2O2 induced oxidative stress. This preliminary study has demonstrated the potential antioxidant effects of RBE in alleviating H2O2-mediated oxidative injuries via upregulation in enzymatic activities and expression levels of CAT

Basic instincts and fatal attractions (STEM Blitz October 2014)

Wheat puroindoline proteins exhibit a unique tryptophan-rich domain. Synthetic peptides based on the amino acid sequence of this domain are antimicrobial and can kill a number of bacteria and fungi. Recorded on 10 October 2014

Molecular characterisation of the protein disulphide isomerase genes of wheat

The protein disulphide isomerases (PDI), enzymes that catalyse the formation, cleavage and isomerisation of disulphide bonds, are suggested to be involved in regulating the folding and deposition of storage protein bodies in the wheat endosperm, thus potentially playing an important role in influencing grain quality. However, limited information exists on the PDI genes in wheat and their possible roles in this process. Via innovative combinations of various experimental approaches such as exploitation of sequence variations between alleles, RFLPs in cDNAs and genomic copies, and direct isolation of gene fragments, we have characterised the individual PDI genes from the common wheat, T. aestivum, the diploid progenitor of its D genome, Ae. tauschii, and the tetraploid progenitor of its A and B genomes, T. turgidum. Ae. tauschii, durum wheat and common wheat exhibit one, two and three PDI gene(s), respectively, and the additional PDI gene suggested to reside on chromosome 1B, if at all present, appears to be a partial, nonexpressed copy. All genes consist of 10 exons and nine introns, with the Ae. tauschii PDI gene showing near complete identity to the corresponding one in common wheat but more limited identity to the A and B genome PDI genes of common wheat and T. turgidum, and the two genes of T. turgidum showing higher degrees of conservation with their counterparts in common wheat rather than between themselves. The sequence variations are being employed for mapping of these genes to find their association with any QTLs

Characterization of waxy proteins and waxy genes of Triticum timopheevii and T. zhukovskyi and implications for evolution of wheat

Abstract not available

Application of a DNA-based test to detect adulteration of bread wheat in pasta

The quality of pasta products is considered the highest if it is made from 100% durum wheat, as the texture of this product is firmer. This characteristic is determined by the hardness (texture) of the wheat grain. Durum wheat is considered genetically 'very hard' as a result of having a deletion of two important genes which impart a degree of softness to common wheat; use of the latter can thus compromise the quality characteristics of pasta to some degree. An application of a qualitative test utilizing the polymerase chain reaction based on these genes was applied to DNA extracted from 20 commercially available pasta samples. The results indicate that common wheat is used in a number of pasta products, some of which do not show this as a listed ingredient

Researching the roles of wheat proteins (Research at Swinburne)

Dr Mrinal Bhave and PhD researcher, Rebecca Alfred, discuss their fascinating work on wheat proteins and talk about the strong relationship between PhD supervisor and candidate

A thylakoid-localised FK506-binding protein in wheat may be linked to chloroplast biogenesis

Plant chloroplasts contain a large proportion of immunophilins, comprising the FK506-binding proteins (FKBPs) and cyclophilins (CYPs), which are members of the peptidyl-prolyl cis/trans isomerase (PPIase) family of proline-folding enzymes. Some of the chloroplastic immunophilins are known to chaperone certain photosynthetic proteins, however the functions of a majority of these proteins are unknown. This work focussed on characterisation of genes encoding the chloroplast-localised FKBP16-1 from wheat and its progenitor species, and identification of its putative promoters, as well as investigations into the effects of light regulation and plant development on its expression. The work identified several alternatively spliced FKBP16-1 transcripts, indicating expression of FKBP16-1 may be post-transcriptionally regulated. FKBP16-1 was expressed in both green and etiolated tissues, and highest levels were detected in developing tissues, indicating a role in chloroplast biogenesis. We also report a novel transcription module, designated 'chloroplast biogenesis module' (CBM) in the FKBP16-1 promoter of cereals that also appears to be involved in the regulation of additional genes involved in chloroplast biogenesis or other aspects of plant development. The results point to considerable potential for a role for FKBP16-1 in early chloroplast development, architecture of photosynthetic apparatus and plant development

Comprehensive analysis of Australian hard wheat cultivars shows limited puroindoline allele diversity

Grain hardness defines the primary commercially important characteristics of wheat, its major grades, its uses and export markets. The puroindoline genes Pina-D1 and Pinb-D1, located only on chromosome 5D of common wheat and encoding small lipid-binding proteins, the puroindolines, are considered to be key genes that determine grain texture, the ‘soft’ texture being wild-type and hard texture being determined by either Pina-D1 gene deletion or a number of separate point mutations in Pinb-D1a, a small number of these being reported to offer different grades of hardness. We have analysed the Pina-D1 and Pinb-D1 genes of 55 Australian hard wheat cultivars, by amplification of the genes, identification of any null mutants, determination of variations in Cleaved Amplified Polymorphic Sequences (CAPS) due to certain point mutations in Pinb-D1, and/or DNA sequencing. The results show that 17 of the hard wheats were Pina-D1b null mutants, 33 others had the well-reported Pinb-D1b glycine-to-serine mutation and 5 were mixed seeds, but none had any other point mutations in Pinb-D1b. The results show that the Australian gene pool is limited in the range of genetically determined grades of hardness to only the two major types. In contrast, of the 30 overseas wheat land-races investigated, 3 exhibited 3 other point mutations in the Pinb-D1 that are suggested to provide different degrees of hardness. Such new genetic resources need to be utilised for the Australian breeding programs to create a range of grain textures suitable for different properties and uses of end-products