Max E. Tate

Hydrophobic properties and chemical characterisation of natural water repellent materials in Australian sands

Water-repellency in non-wetting sands is due to hydrophobic waxes present on the surface of sand grains and contained in particulate organic matter present in these sands. This study investigates the physico-chemical characteristics of these natural waxes and compares them to waxes extracted from potential original source materials. Non-polar and polar hydrophobic wax extracts were obtained from whole non-wetting sand, and its individual constituents, and associated organic matter. These included the sand fraction, the intrinsic particulate organic matter, tree litter, eucalyptus leaves, bark, lucerne and lupin plants, and fungi and actinomycetes isolated from these sands. Waxes were characterised for their hydrophobic properties and composition of their chemical constituents. The hydrophobicities of the waxes were assessed by measuring the water-repellency induced after treating acid washed sand with wax extracts. Non-polar and polar wax extracts of the tree litter displayed hydrophobic properties that were similar to the corresponding waxes isolated from non-wetting sand and intrinsic particulate organic matter. Unlike these plant-derived waxes, the microbial wax extracts possessed different hydrophobic properties. Characterisation of the components of the extracted waxes by gas chromatography-mass spectroscopy (GC-MS) analysis revealed a strong similarity in the composition of waxes isolated from non-wetting sand, tree litter and other plant material. The major components found were unbranched and branched C16 to C36 fatty acids and their esters, alkanes, phytanols, phytanes, and sterols. Some of these components were not detected in the microbial waxes. Unextracted samples, as well as wax extracts of non-wetting sand, intrinsic particulate organic matter, tree litter and fresh plant material were further analysed by solution and solid state Nuclear Magnetic Resonance spectroscopy which revealed the relative content of the different chemical species present.

Studies on non-wetting sands. I: The role of intrinsic particulate organic matter in the development of water-repellency in non-wetting sands

The bulk of the organic matter in sands from the south-east of South Australia is present as discrete particles which constitute 4-6% of the mass of the sand. Hydrophobic particulate organic matter was separated from non-wetting sand obtained from two sites in the south-east of South Australia and characterized with respect to size and ability to induce water-repellency. When heated with both a wettable acid washed sand and a natural sand (non-wetting sand washed free of particulate organic matter), the intrinsic particulate organic matter induced strong water-repellence. The degree of hydrophobicity created was higher with the natural-washed sand than the acid-washed sand which indicated that a precoated surface, even one with a low initial hydrophobicity, has a strong enhancing effect. Particulate organic matter, especially the larger size fractions, acted as a reservoir of waxes or hydrophobic materials which diffused onto the surfaces of sand grains during heating, and particularly during wetting/heating/drying cycles. Thus, intrinsic particulate organic matter plays a substantial role in the development of water-repellency in sandy soils. In addition to hydrophobic waxes which diffuse out under environmental conditions prevalent in the field, water-repellency increases significantly when these hydrophobic particles interact with the natural precoated hydrophobic surface of the sand.

Agropine: A revised structure

Abstract The product known as agropine from crown-gall tumour is shown to be indistinguishable in all of its properties (physical, chemical, and biological) from N 2 -(1′-deoxy- d -mannitol-l′-yl)- l -glutamine, 1,2′-lactone, a C 11 H 20 N 2 O 7 compound produced by cyclisation of N 2 -(l′-deoxy- d -mannitol-l′-yl)- l -glutamine. Two prior assignments of a C 11 H 17 NO 7 formula obtained by high-resolution electron-impact mass spectrometry have been shown by field-desorption mass spectrometry to correspond to a fragment produced by the rapid loss of ammonia from the parent molecular species.

Charge equilibria and pKa of malvidin-3-glucoside by electrophoresis

Paper electrophoresis has been used over the pH range 1.2 to 10.4 to measure apparent pK(a) values for malvidin-3-O-glucoside of pK(a(1)) 1.76+/-0.07, pK(a(2)) 5.36+/-0.04, and pK(a(3)) 8.39+/-0.07. Using solvent partitioning between buffered aqueous solutions and n-octanol, several micro-pK(a) constants for malvidin-3-O-glucoside were also identified, highlighting the complex nature of malvidin-3-glucoside equilibria. As a nonspectrophotometric procedure, the charge-dependent electrophoretic mobility method provided independent information on the net charge and color of anthocyanin species at wine pH (ca. 3.6). At this pH, the color of malvidin-3-glucoside in red wines is consistent only with the uncharged quinonoidal base as a major colored component of the equilibria.

Proteinaceous Metabolites from Pyrenophora teres Contribute to Symptom Development of Barley Net Blotch

ABSTRACT Pyrenophora teres, the causal agent of net blotch of barley (Hordeum vulgare L.), induces a combination of necrosis and extensive chlorosis in susceptible barley cultivars. Cell-free filtrates from both net and spot forms of P. teres; P. teres f. sp. teres, and P. teres f. sp. maculata were found to contain phytotoxic low molecular weight compounds (LMWCs) and proteinaceous metabolites which appear to be responsible for different components of the symptoms induced by the two forms of the pathogen in a susceptible cultivar of barley (cv. Sloop). Proteins induced only brown necrotic spots or lesions similar to those induced by the pathogens 72 h after inoculation. In contrast, LMWCs induced general chlorosis seen 240 h after inoculation but not the localized necrosis. Neither hydrolyzed or heat- or protease-treated proteinaceous metabolites induced the symptoms. This is the first report of the involvement of proteins produced by P. teres in symptom development during net blotch disease of barley.

Lignan and phenylpropanoid glycerol glucosides in wine

Abstract Three glycoconjugates, 1-O-(β- D -glucopyranosyl)-2-[2-methoxy-4-(ω-hydroxypropyl)-phenoxy]-propan-3-ol, 1,2,3,4-tetrahydro-7-hydroxy-1-(4′-β-glucopyranosyl-3′-metho1xyphenyl)-6-methoxy-2,3-naphthalenedimethanol (isolariciresinol-β-4′-O-glucopyranoside) and, tentatively, 2,3-bis(4′-hydroxy-3′-methoxybenzyl)-butane-1,4-diol-β- D -glucoside (seco-isolariciresinol-β- D -glucoside) have been detected in Riesling wine by FAB-mass spectrometry/mass spectrometry and subsequently isolated and identified by spectral and chemical studies. The first of these compounds is a new shikimic acid metabolite of wine, and the latter two lignans represent a new category of wine phenols.

Phytotoxic metabolites from Drechslern wirreganensis and D. campanulata

Phytotoxic components detected by a bean (Vicia faba) leaf assay were isolated from extracts of dried mycelia and liquid culture filtrates of Drechslern wirreganensis and D. campanulata by preparative thin layer chromatography. Mass spectrometric examination of chromatographically homogeneous phytotoxic fractions was consistent with the presence of cytochalasin B and dihydrocytochalasins in both fungi. Cytochalasin B was present at 10.3 g/kg dry weight of the mycelium for D. wirreganensis and 7.7 g/kg for D. campanulata. In addition, differences were observed in the minor cytochalasin components. In D. wirreganensis, a more hydrophobic cytochalasin derivative with an ion at m/z 675 was present. In D. campanulata a component of similar hydrophobicity was present, but with an ion at 481 m/z. Measurable inhibition of wheat seed germination by cytochalasin B was observed only at or above 70 μм in 1% dimethyl sulfoxide solution. The formation of bi-nucleate cells, a common feature in mammalian cells treated with cytochalasin B, is reported in barley root tips. Differences in lesion morphology caused by these two related pathogenic fungi are also associated with differences in types and amounts of the phytotoxic components they produce.

Glucosides of ethyl indole-3-lactate and uroterpenol in riesling wine

Abstract Two novel glycoconjugates, ethyl indole-3-lactate- O -β- d -glucopyranoside and p -menth-1-ene-8,9-diol-9-β- d -glucopyranoside have been detected in Riesling wine by FAB-MS/MS and subsequently isolated and identified via spectral and chemical data.

Genetics of colour traits in common vetch (Vicia sativa L.)

Five parents of common vetch (Vicia sativa L.) having orange/beige cotyledon colour, brown/white testa colour, purple/green seedling colour and purple/white flower colour were crossed as a full diallele set. The inheritance patterns of cotyledon, testa or seed coat colour, flower and seedling colour, were studied by analyzing their F1, F2, BC1 and BC2 generations. The segregation pattern in F2, BC1 and BC2, showed that cotyledon colour was governed by a single gene with incomplete dominance and it is proposed that cotyledon colour is controlled by two allelic genes, which have been designated Ct1 and Ct2. Testa colour was governed by a single gene with the brown allele dominant and the recessive allele white. This gene has been given the symbol H. Two complementary genes governed both flower and seedling colours. These flower and seedling colour genes are pleiotropic and the two genes have been given the symbols S and F.

Use of solid and gel state 13C NMR spectroscopy for differentiation between agarophytes and carrageenophytes

Both solid state (CP-MAS) and gel state (using standard solution state conditions) 13C NMR spectroscopy have been used to characterize a range of red algae that produce either agar or carrageenan. These techniques allow rapid determination of phycocolloid type within the algal tissue before extensive and time-consuming extractions and fractionations are carried out.