Cooperative Research Centre

About: Cooperative Research Centre is a based out in . It is known for research contribution in the topics: Population & Sea ice. The organization has 7633 authors who have published 8607 publications receiving 429721 citations.

Analysis of starch structure using fluorophore‐assisted carbohydrate electrophoresis

Abstract: The analysis of the fine structure of starches is important to the investigation of linkages between starch structure and function and to the investigation of the properties and roles of starch biosynthetic, modifying and degradation enzymes. Fluorophore-assisted carbohydrate electrophoresis has recently been introduced as a method for the analysis of the oligosaccharide populations released by the enzymatic digestion of starches, which has advantages in resolution and sensitivity over previously used methods, and provides the capacity for the facile analysis of oligosaccharide populations on either a molar or mass basis. The use of fluorophore-assisted carbohydrate electrophoresis for the analysis of oligosaccharides is reviewed with particular reference to the choice of label, efficiency of labeling and separation techniques. Examples of separations using slab gel electrophoresis, DNA sequencer analysis and capillary electrophoresis are presented and we conclude that on the basis of resolution and reproducibility, capillary electrophoresis is the method of choice for the separation of oligosaccharides of degree of polymerization from 1 to 100. Examples of isoamylase-debranched starches and glycogens analyzed by capillary electrophoresis are presented. The capillary electrophoresis analysis of starch structure through the analysis of oligosaccharides released by the debranching of limit dextrins derived from starches and glycogens is introduced as a useful diagnostic of starch structure. The potential for future development of novel diagnostics for starch structure using fluorophore-assisted carbohydrate electrophoresis is discussed.

Large‐scale assessments of river health using an Index of Biotic Integrity with low‐diversity fish communities

Abstract: SUMMARY 1. Effective tools are needed to measure the ‘health’ of rivers at scales large enough to be useful for management. Indicators for assessing the complex of variables that constitutes river health need to be ecologically based, efficient, rapid and consistently applicable in different ecological regions. 2. A large-scale survey of rivers in New South Wales, Australia provided data to test the Index of Biotic Integrity (IBI). The IBI employs the fish-community attributes, identified using regional and river-size data, expected for a river reach of excellent environmental quality. It uses metrics based on species richness, abundance, community structure and the health of individual fish. IBI metrics were established to suit a relatively low-diversity and unspecialized freshwater fish fauna in south-eastern Australia, totalling 55 species. 3. The IBI was able to discriminate between relative levels of environmental quality within a diverse set of stream systems and four presumptive ecological regions. The index was validated by testing the repeatability of scores, and by comparison of IBI scores at eighty sites with an independent measure of potential catchment condition, the River Disturbance Index. 4. Assessments of metric performance showed that eleven of the twelve metrics contributed satisfactorily. One metric based on trophic guild performed poorly and should be deleted from the index. Six other recommendations are made to enhance the performance of the IBI. 5. Results show that, while all large rivers have been disturbed, rivers in the Murray region and those in many coastal montane areas are particularly degraded. 6. The IBI results presented here demonstrate a validated method for large-scale monitoring of river health based on a fish fauna of limited diversity, in the absence of suitable reference sites.

Light inactivation of functional photosystem II in leaves of peas grown in moderate light depends on photon exposure

Abstract: To determine the dependence of in vivo photosystem (PS) II function on photon exposure and to assign the relative importance of some photoprotective strategies of PSII against excess light, the maximal photochemical efficiency of PSII (Fv/Fm) and the content of functional PSII complexes (measured by repetitive flash yield of oxygen evolution) were determined in leaves of pea (Pisum satlvum L.) grown in moderate light. The modulation of PSII functionality in vivo was induced by varying either the duration (from 0 to 3 h) of light treatment (fixed at 1200 or 1800 μmol photons · m-2 · s-1) or irradiance (from 0 to 3000 μmol photons · m-2 · s-1) at a fixed duration (1 h) after infiltration of leaves with water (control), lincomycin (an inhibitor of chloroplast-encoded protein synthesis), nigericin (an uncoupler), or dithiothreitol (an inhibitor of the xanthophyll cycle) through the cut petioles of leaves of 22 to 24-day-old plants. We observed a reciprocity of irradiance and duration of illumination for PSII function, demonstrating that inactivation of functional PSII depends on the total number of photons absorbed, not on the rate of photon absorption. The Fv/Fm ratios from photoinhibitory light-treated leaves, with or without inhibitors, declined pseudo-linearly with photon exposure. The number of functional PSII complexes declined multiphasically with increasing photon exposure, in the following decreasing order of inhibitor effect: lincomycin > nigericin > DTT, indicating the central role of D1 protein turnover. While functional PSII and Fv/Fm ratio showed a linear relationship under high photon exposure conditions, in inhibitor-treated leaves the Fv/Fm ratio failed to reveal the loss of up to 25% of the total functional PSII under low photon exposure. The loss of this 25% of less-stable functional PSII was accompanied by a decrease of excitation-energy trapping capacity at the reaction centre of PSII (revealed by the fluorescence parameter, 1/Fo-1/Fm, where Fo and Fm stand for chlorophyll fluorescence when PSII reaction centres are open and closed, respectively), but not by a loss of excitation energy at the antenna (revealed by the fluorescence parameter, 1/Fm). We conclude that (i) PSII is an intrinsic photon counter under photoinhibitory conditions, (ii) PSII functionality is mainly regulated by D1 protein turnover, and to a lesser extent, by events mediated via the transthylakoid pH gradient, and (iii) peas exhibit PSII heterogeneity in terms of functional stability during photon exposure.

The Genome Health Clinic and Genome Health Nutrigenomics concepts: diagnosis and nutritional treatment of genome and epigenome damage on an individual basis.

Abstract: The evidence of a direct link between increased genome/ epigenome damage and elevated risk for adverse health outcomes during the various stages of life, such as infertility, foetal development and cancer is becoming increasingly stronger. The latter is briefly reviewed against a background of evidence indicating that genome and epigenome damage biomarkers, in the absence of overt exposure of genotoxins, are themselves sensitive indicators of deficiency in micronutrients required as cofactors or as components of DNA repair enzymes, for maintenance methylation of CpG sequences and prevention of DNA oxidation and/or uracil incorporation into DNA. The latter is illustrated with crosssectional and dietary intervention data obtained using the micronucleus assay and other efficient biomarkers for diagnosing genome and/or epigenome instability. The concept of recommended dietary allowances for genome stability and how this could be achieved is discussed. The ‘Genome Health Nutrigenomics’ concept is also introduced to define and focus attention on the specialized research area of how diet impacts on genome stability and how genotype determines nutritional requirements for genome health maintenance. The review concludes with a vision for a paradigm shift in disease prevention strategy based on the diagnosis and nutritional treatment of genome/epigenome damage on an individual basis, i.e. The Genome Health Clinic.