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Item Metadata only (1,3)-β-glucan synthases in barley(Dept Plant Science, 2000) Li, J.; Burton, R.; Paech, N.; Koltunow, A.; Langridge, P.; Fincher, G.; 8th International Barley Genetics Symposium (22 Oct 2000 : Adelaide, Australia); Logue, D.Item Metadata only (1,3;1,4)-beta-D-glucans in cell walls of the Poaceae, lower plants, and fungi: A tale of two linkages(Oxford University Press, 2009) Burton, R.; Fincher, G.(1,3;1,4)-β-D-Glucans consist of unbranched and unsubstituted chains of (1,3)- and (1,4)-β-glucosyl residues, in which the ratio of (1,4)-β-D-glucosyl residues to (1,3)-β-D-glucosyl residues appears to influence not only the physicochemical properties of the polysaccharide and therefore its functional properties in cell walls, but also its adoption by different plant species during evolution. The (1,3;1,4)-β-D-glucans are widely distributed as non-cellulosic matrix phase polysaccharides in cell walls of the Poaceae, which evolved relatively recently and consist of the grasses and commercially important cereal species, but they are less commonly found in lower vascular plants, such as the horsetails, in algae and in fungi. The (1,3;1,4)-β-D-glucans have often been considered to be components mainly of primary cell walls, but recent observations indicate that they can also be located in secondary walls of certain tissues. Enzymes involved in the depolymerisation of (1,3;1,4)-β-D-glucans have been well characterized. In contrast, initial difficulties in purifying the enzymes responsible for (1,3;1,4)-β-D-glucan biosynthesis slowed progress in the identification of the genes that encode (1,3;1,4)-β-D-glucan synthases, but emerging comparative genomics and associated techniques have allowed at least some of the genes that contribute to (1,3;1,4)-β-D-glucan synthesis in the Poaceae to be identified. Whether similar genes and enzymes also mediate (1,3;1,4)-β-D-glucan biosynthesis in lower plants and fungi is not yet known. Here, we compare the different fine structures of (1,3;1,4)-β-D-glucans across the plant kingdom, present current information on the genes that have been implicated recently in their biosynthesis, and consider aspects of the cell biology of (1,3;1,4)-β-D-glucan biosynthesis in the Poaceae.Item Metadata only (1,3;1,4)-β-glucan biosynthesis by the CSLF6 enzyme: position and flexibility of catalytic residues influence product fine structure(American Chemical Society, 2016) Dimitroff, G.; Little, A.; Lahnstein, J.; Schwerdt, J.; Srivastava, V.; Bulone, V.; Burton, R.; Fincher, G.Cellulose synthase-like F6 (CslF6) genes encode polysaccharide synthases responsible for (1,3;1,4)-β-glucan biosynthesis in cereal grains. However, it is not clear how both (1,3)- and (1,4)-linkages are incorporated into a single polysaccharide chain and how the frequency and arrangement of the two linkage types that define the fine structure of the polysaccharide are controlled. Through transient expression in Nicotiana benthamiana leaves, two CSLF6 orthologs from different cereal species were shown to mediate the synthesis of (1,3;1,4)-β-glucans with very different fine structures. Chimeric cDNA constructs with interchanged sections of the barley and sorghum CslF6 genes were developed to identify regions of the synthase enzyme responsible for these differences. A single amino acid residue upstream of the TED motif in the catalytic region was shown to dramatically change the fine structure of the polysaccharide produced. The structural basis of this effect can be rationalized by reference to a homology model of the enzyme and appears to be related to the position and flexibility of the TED motif in the active site of the enzyme. The region and amino acid residue identified provide opportunities to manipulate the solubility of (1,3;1,4)-β-glucan in grains and vegetative tissues of the grasses and, in particular, to enhance the solubility of dietary fibers that are beneficial to human health.Item Metadata only 1-MCP does not improve the shelf-life of Chinese cabbage(John Wiley & Sons Ltd, 2005) Porter, Kerry Louise; Collins, Graham George; Klieber, Andreas; School of Agriculture, Food and WineItem Metadata only 1-MCP is more effective on a floral brassica (Brassica oleracea var. italica L.) than a leafy brassica (Brassica rapa var. chinensis)(Elsevier Science BV, 2002) Able, A.; Wong, L.; Prasad, A.; O'Hare, T.Florets of broccoli (Brassica oleracea var. italica L.) and the youngest fully expanded leaf detached from pak choy (Brassica rapa var. chinensis) were treated with 1-methylcyclopropene (1-MCP) overnight (16 h) and then stored at supermarket retail temperature (10 °C). A concentration of 12 μl l−1 was considered optimal for both pak choy leaves and broccoli florets. 1-MCP increased shelf life of broccoli florets by just greater than 20% but had little effect on pak choy shelf life (increases between 10 and 20%) in the absence of exogenously applied ethylene. Multiple applications had no further impact while 1-MCP needed to be applied as soon as possible after harvest to have maximal effect. If 1-MCP treatment was applied overnight at 20 °C prior to storage at 10 °C, its effect was slightly increased. However, 1-MCP did protect broccoli and pak choy from the effects of exogenously applied ethylene (0.1 or 1 μl l−1) suggesting it may be useful during retail or storage with ethylene-producing commodities. Differences between the efficacies of 1-MCP on florets compared with leaves are discussed.Item Metadata only 1ollective selection of food patches in Drosophila(Company of Biologists Ltd., 2016) Lihoreau, M.; Clarke, I.; Buhl, J.; Sumpter, D.; Simpson, S.The fruit fly Drosophila melanogaster has emerged as a model organism for research on social interactions. Although recent studies have described how individuals interact on foods for nutrition and reproduction, the complex dynamics by which groups initially develop and disperse have received little attention. Here we investigated the dynamics of collective foraging decisions by D. melanogaster and their variation with group size and composition. Groups of adults and larvae facing a choice between two identical, nutritionally balanced food patches distributed themselves asymmetrically, thereby exploiting one patch more than the other. The speed of the collective decisions increased with group size, as a result of flies joining foods faster. However, smaller groups exhibited more pronounced distribution asymmetries than larger ones. Using computer simulations, we show how these non-linear phenomena can emerge from social attraction towards occupied food patches, whose effects add up or compete depending on group size. Our results open new opportunities for exploring complex dynamics of nutrient selection in simple and genetically tractable groups.Item Metadata only (+)-(1R 2S 3R)-2-[(Benzyloxycarbonyl)methyl]-3-phenylcyclopropanecarboxylic acid(Blackwell Munksgaard, 2007) Avery, T.; Greatrex, B.; Taylor, D.; Tiekink, E.In the title compound, C19H18O4, the carboxyl group lies on the opposite side of the cyclo-propane ring to the other substituents. Mol-ecules associate via (⋯HOC=O)2 synthons around centres of symmetry and are linked into double layers by cooperative C - H⋯O contacts. © International Union of Crystallography 2007.Item Metadata only (+)-(1R 2S 3S 4S)-2-Chloro-3-(phenylselanyl)cyclohexane-1 4-diol(Blackwell Munksgaard, 2007) Robinson, A.; Taylor, D.; Tiekink, E.The cyclo-hexyl ring in the title compound, C12H15ClO2Se, has a chair conformation with the 4-hydr-oxy group occupying an axial position; the other non-H substituents occupy equatorial positions. Mol-ecules aggregate via O - H⋯O hydrogen bonds into a supra-molecular helical chain. © International Union of Crystallography 2007.Item Metadata only 2,2-DPA resistance in giant Parramatta grass (Sporobolus fertilis)(The Weed Society of Queensland Inc, 2008) Ramasamy, S.; McLaren, D.; Pritchard, G.; Officer, D.; Bonilla, J.; Preston, C.; Lawrie, A.; Australian Weeds Conference (16th : 2008 : Cairns, Qld.)Item Metadata only 2-[(3S,3aS,5R,8S,8aS)-3,8-Dimethylhexahydro-1H,4H-3a,8a-epoxyazulen-5-yl] -propan-2-ol(International Union of Crystallography, 2014) Burrett, S.; Taylor, D.; Tiekink, E.Four independent mol-ecules (A-D) comprise the asymmetric unit of the title compound, C15H26O2, which differ only in the relative orientations of the terminal -C(Me)2OH groups [e.g. the range of Cmethyl-ene-Cmethine-Cquaternary-Ohy-droxy torsion angles is 52.7 (7)-57.1 (6)°, where the Cmethyl-ene atom is bound to an epoxide C atom]. The five-membered rings adopt envelope conformations, with the methyl-ene C atom adjacent to the methine C atom being the flap atom in each case. In each mol-ecule, the conformation of the seven-membered ring is a half-chair, with the Cmethyl-ene-Cmethine bond, flanked by methyl-ene C atoms, being the back of the chair. Supra-molecular helical chains along the b axis are found in the crystal packing, sustained by hy-droxy-epoxide O-H⋯O hydrogen bonding. Mol-ecules of A self-associate into a chain as do those of D. A third independent chain comprising B and C mol-ecules is also formed. The studied crystal is a pseudo-merohedral twin (minor component ca 21%).Item Metadata only 2019 Daniel McAlpine Memorial Lecture. Grapevine powdery mildew: from fundamental plant pathology to new and future technologies(Springer Science, 2021) Scott, E.S.Grapevine powdery mildew, caused by the fungus Erysiphe necator (formerly Uncinula necator), is a widespread disease which can reduce yield and quality of grapes and compromise wine quality. As an obligately biotrophic pathogen of a woody perennial crop, E. necator presents challenges for researchers studying aspects of biology, epidemiology and management. The disease can be difficult to detect, especially in the early stages, as signs and symptoms are often inconspicuous. Failure to control powdery mildew early, inadequate spray coverage and or fungicide resistance may lead to significant damage. Because of the negative effects of disease on wine quality, many wineries set thresholds for acceptability of grapes for winemaking, typically 3–5% of the surface area of bunches affected. This is usually determined by visual inspection in the vineyard close to harvest or at the winery. Visual assessment is subjective and prone to inaccuracy, and the wine industry seeks a rapid and reliable objective measure for disease severity. In this paper, I describe some of the challenges of research on the biology and management of grapevine powdery mildew and how these have been addressed using fundamental approaches in plant pathology. Recent research towards development of objective measures is presented and technologies that have potential for application in the vineyard or winery in the future to facilitate disease diagnosis, quantification and management are considered.Item Metadata only 3.2.9 Grasses(Elsevier Science B.V., 1996) Frost, William E.; Ridland, P. M.; School of Agriculture, Food and Wine : Plant and Food ScienceItem Metadata only -308 Nco I polymorphism of tumour necrosis factor a in overweight caucasians(Elsevier Sci Ireland Ltd, 2003) Coates, A.; Heilbronn, L.; Noakes, M.; Kind, K.; Clifton, P.We investigated whether a polymorphism in the promoter region of the TNFα gene (−308 A/G) is associated with reduced weight loss in obese Australian subjects on an energy restricted diet. 189 healthy subjects and 91 subjects with type II diabetes were genotyped for the −308 Nco I polymorphism using PCR-RFLP techniques. A subset of these subjects (211 females and 45 males), were placed on a 30% energy restricted diet (6200 kJ) for 12 weeks. Subjects were assessed every 2 weeks and changes in body weight, waist circumference and BMI were used as determinants of weight loss. Fasting plasma was analysed for glucose, insulin, lipids and free fatty acids. 64% of subjects were GG homozygotes, 31% were AG heterozygotes and 5% were AA homozygotes. There was no significant difference between the allele frequency in healthy subjects (0.21) and type 2 diabetic patients (0.24). The presence of the −308 A/G polymorphism did not significantly influence initial BMI, the amount of weight lost (GG, 8.1±0.65 kg, AG, 6.9±0.77 kg, AA, 7.6±0.12 kg), waist circumference or any metabolic variable. The AA variant at position −308 in the promoter region of the TNFα gene does not influence the amount of weight lost in overweight and obese men and women on a 30% energy restricted diet.Item Open Access 3D visualisation of voids in grapevine flowers and berries using X‐ray micro computed tomography(Wiley, 2021) Xiao, Z.; Stait‐Gardner, T.; Willis, S.A.; Price, W.S.; Moroni, F.J.; Pagay, V.; Tyerman, S.D.; Schmidtke, L.M.; Rogiers, S.Y.Background and Aim: X-ray micro computed tomography (micro-CT) is a non-destructive 3D imaging technique that has been applied to plant morphology and anatomical studies to gain a better understanding of physiological phenomena in vivo. It is particularly useful for imaging voids in undisturbed fragile tissues and therefore may be applied to the delicate flowers and soft berries of Vitis vinifera. The characterisation of gas spaces and channels can offer insights into the process of tissue aeration and this may have implications on cell function and vitality. We assessed the use of micro-CT to visualise voids within these reproductive organs. Methods and Results: The internal structures of flowers and berries were captured through rapid micro-CT scanning and subsequently were recreated in 3D using image processing. The relative positions of the developing flower parts encased within the flower cap were visualised. Low density/porous tissue was identified within the pedicel and receptacle, con- necting the lenticels with the interior of the berry. Voids were present in the proximal mesocarp of mature berries forming a ‘detachment zone’ in both seeded and seedless cultivars. Voids permeated the mesocarp of mature seedless grape cultivars, but not seeded grapes. Conclusion: Micro-CT offers new insights regarding the distribution of voids on the morphology and compositional hetero- geneity of organs that are difficult to dissect and/or view with light microscopy. Significance of the Study: A better understanding of the physiology and functionality of grapevine reproductive tissues may be achieved by 3D visualisation of internal structure in vivo.Item Metadata only 4,4'-Dihydroxy-3,3',5,5'-tetramethoxyazodioxybenzene: an unexpected dimer formed during hydroxylamine extractions of wheat flour(Pergamon-Elsevier Science Ltd, 2006) Asenstorfer, R.; Mares, D.Neutral hydroxylamine extracts of wheat contained a product that was colourless at pH<5 (λ max 340 nm) and yellow at pH>9 (λ max 400 nm). ESI-MS showed a major ion m/z 184.0 and a possible parent ion m/z 367.2 (MH⁺) suggesting that the product resulted from the reaction of 2,6-dimethoxy-p-quinone with hydroxylamine. However, mass spectral and other spectroscopic data indicated that the compound was neither of the 2,6-dimethoxy-p-quinone oximes. A product with identical absorbance, mass spectrum, electrophoretic mobility and HPLC retention time as the pigment from hydroxylamine extracts of flour was observed amongst the reaction products of hydroxylamine and 1,4-dihydroxy-2,6-dimethoxybenzene. The structure of this product was identified by NMR, 2D NMR and IR as 4,4′-dihydroxy-3,3′,5,5′-tetramethoxyazodioxybenzene.Item Metadata only (+)-(5S)-5-[(1S)-2-Benzoyl-1-hydroxyethyl]-1 2 3 4-tetrahydrofuran-2-one(Blackwell Munksgaard, 2007) Cuthbert, J.; Taylor, D.; Tiekink, E.The title compound, C13H14O4, displays a kinked conformation in which the hydr-oxy group is orientated over the furan-one ring. Mol-ecules aggregate into linear supra-molecular chains via O - H⋯O inter-actions, and C - H⋯O contacts link these chains into two-dimensional arrays. © International Union of Crystallography 2007.Item Metadata only 6-Benzylamino purine stimulates in vitro shoot organogenesis in Eucalyptus erythronema, E. stricklandii and their interspecific hybrids(ELSEVIER SCIENCE BV, 2006) Glocke, Pauline Lesley; Collins, Graham George; Sedgley, Margaret; School of Agriculture, Food and Wine; School of Agriculture, Food and WineItem Metadata only 8 prenylnaringenin novel phytoestrogen, inhibits angiogenesis in vitro and vivo.(Wiley-Liss, 2004) Pepper, M.; Hazel, S.; Humpel, M.; Schleuning, W.8-Prenylnaringenin is a recently discovered phytoestrogen. Using an in vitro model of angiogenesis in which endothelial cells can be induced to invade a three-dimensional collagen gel within which they form capillary-like tubes, we demonstrate that 8-prenylnaringenin inhibits angiogenesis induced by basic fibroblast growth factor (bFGF), vascular endothelial growth factor (VEGF), or the synergistic effect of the two cytokines in combination, with an IC(50) of between 3 and 10 microM. This effect was seen with bovine microvascular endothelial cells derived from the adrenal cortex (BME cells) and with endothelial cells from the bovine thoracic aorta (BAE cells). The inhibitory effects of 8-prenylnaringenin were found to be roughly equipotent to those of genistein that has previously been shown to inhibit angiogenesis in vitro. Early chorioallantoic membrane (CAM) assay results showed reductions in both vessel lengths and vein diameters, with similar potency in the 8-prenylnaringenin and genistein groups. Similar effects on the CAM vessels were seen when the two substances were co-added. These findings suggest that 8-prenylnaringenin has potential therapeutic applications for diseases in which angiogenesis is an important component.Item Metadata only 8th International Barley Genetics Symposium Volume I(Festival City Conventions Pty Ltd, 2000) Logue, Susan J.; School of Agriculture, Food and WineItem Metadata only 8th International Barley Genetics Symposium Volume II(Festival City Conventions Pty Ltd, 2000) Logue, Susan J.; School of Agriculture, Food and Wine