Enzymatic and chemical treatment limits on the controlled solubilization of brewers' spent grain

The enzymatic hydrolysis of brewers' spent grain (BSG) has been investigated through treatment with commercial carbohydrases and proteases. Resultant residues were then chemically fractionated and delignified. Enzymatic treatments released 25-30% of the BSG mass and yielded precursors suitable for subsequent conversion to potentially value-added products. Controlled chemical fractionation selectively solubilized arabinoxylan but with no differences apparent due to prior enzyme treatment. The loss of non-polysaccharide components during alkali treatment suggests the presence of a high proportion of alkali-soluble lignin. Further delignification of the alkali-insoluble residues and further chemical fractionation released the remaining hemicellulose, to yield a residue which was >90% cellulose. Further knowledge of the properties and interaction between BSG polymers will facilitate an improved enzyme-assisted total deconstruction of BSG and hence the exploitation of its biomass.     

Environmental change hastens the demise of the critically endangered riverine rabbit (Bunolagus monticularis)

Declining population numbers coupled with the growing evidence of global change have focussed attention on the critically endangered riverine rabbit (Bunolagus monticularis) endemic to South Africa. The aim of this study is to develop a habitat model to aid in the identification of isolated populations, offer opportunities for re-introduction or introduction, and guide future conservation efforts by assessing the possible impacts of global change. We attempt a novel approach where plant species which afford the riverine rabbit cover from predation and its primary food sources are modelled utilising the same technique and are included as a predictor variable in the habitat model for both current and future projections of potential habitat. Inclusion of this proximal variable as well as riparian areas yields a more parsimonious habitat model than using climatic variables alone. Results suggest that unsurveyed suitable habitat east of Victoria West might harbour previously overlooked isolated populations or offer new opportunities for re-introductions. Future climatic conditions under the most severe general circulation model for the region (HADCM3) suggest that, on average, in excess of 96% of the current habitat could become unsuitable, mitigated only slightly by a possible 7% increase in range in adjacent upper catchment areas. Consideration of existing land transformation increases this range reduction by a further 1%. Given that ex situ captive breeding programmes have met with no success and that the bulk of future potential range lies well outside of the currently known and surveyed areas the current adaptation options of conservancy establishment and captive breeding need to be re-evaluated. Without positive human intervention the future of the critically endangered riverine rabbit under conditions of global change seems certain.     

Determination of residues of alachlor and its metabolite in corn, soybeans, and potatoes as heptafluorobutyryl-2,6-diethylaniline

Alachlor [2-chloro-2',6'-diethyl-N-(methoxymethyl)acetanilide] was determined by hydrolysis to 2,6-diethylaniline with 6N HCl and quantitation of the heptafluorobutyryl derivative by gas chromatography with electron capture detection. 2,6-Diethylaniline was isolated from the hydrolysate by steam distillation, derivatized with heptafluorobutyric anhydride, and the derivative was purified by chromatography on silicic acid with 60% toluene in hexane as eluant. Recoveries from potatoes, soybeans, and corn spiked at levels from 3 to 26 ppb averaged 81, 90, and 96% respectively.     

Making Asian students,making students Asian: The racialisation of export education in Auckland,New Zealand

Abstract: In recent years, international education has become a source of considerable political, academic and media debate in New Zealand. This is nowhere more the case than with regards to Auckland, the New Zealand city that has hosted the greatest number of international students. This paper focuses on the media debates around international students in Auckland with particular emphasis on the representations of the largest group of international students, those who originate from countries within the North‐East Asian region. The media representations of these students have fixed a diverse group of individuals within a singular racial identity that is known by stereotypical economic, cultural and social characteristics. As a result, these representations have further problematised the interaction between international students and the host population in Auckland while simultaneously implicating a cohort of young New Zealand citizens and permanent residents who are of similar descent within the same discourses. This process of othering the Asian student, regardless of citizenship, has consequences not simply for the practice of exporting education in this city but also for the future of a multicultural Auckland and New Zealand.     

Linkage mapping and genome analysis in a Saccharum interspecific cross using AFLP, SRAP and TRAP markers

Framework genetic linkage maps of two progenitor species of cultivated sugarcane, Saccharum officinarum ‘La Striped’ (2n = 80) and S. spontaneum ‘SES 147B’ (2n = 64) were constructed using amplified fragment length polymorphism (AFLP), sequence related amplified polymorphism (SRAP), and target region amplification polymorphism (TRAP) markers. The mapping population was comprised of 100 F₁ progeny derived from the interspecific cross. A total of 344 polymorphic markers were generated from the female (S. officinarum) parent, out of which 247 (72%) were single-dose (segregating in a 1:1 ratio) and 33 (9%) were double-dose (segregating in a 3.3:1 ratio) markers. Sixty-four (19%) markers deviated from Mendelian segregation ratios. In the S. spontaneum genome, out of a total of 306 markers, 221 (72%) were single-dose, 43 (14%) were double-dose, and 42 markers (14%) deviated from Mendelian segregation ratios. Linkage maps with Kosambi map distances were constructed using a LOD score ≥5.0 and a recombination threshold of 0.45. In Saccharum officinarum, 146 markers were linked to form 49 linkage groups (LG) spanning 1732 cM whereas, in S. spontaneum, 121 markers were linked to form 45 LG spanning 1491 cM. The estimated genome size of S. officinarum ‘La Striped’ was 2448 cM whereas that of S. spontaneum ‘SES 147B’ was 3232 cM. Based on the two maps, genome coverage was 69% in S. officinarum and 46% in S. spontaneum. The S. officinarum parent ‘La Striped’ behaved like an auto-allopolyploid whereas S. spontaneum ‘SES 147B’ behaved like a true autopolyploid. Although a large disparity exists between the two genomes, the existence of simple duplex markers, which are heterozygous in both parents and segregate 3:1 in the progeny, indicates that pairing and recombination can occur between the two genomes. The study also revealed that, compared with AFLP, the SRAP and TRAP markers appear less effective at generating a large number of genome-wide markers for linkage mapping in sugarcane. However, SRAP and TRAP markers can be useful for QTL mapping because of their ability to target gene-rich regions of the genome, which is a focus of our future research.     

Distribution of CCR3 mRNA expression in horse tissues

CCL11 (also known as eotaxin) is a very potent and selective mediator of eosinophil migration which exerts its effects through its receptor, CCR3. In this study we report the cloning of an equine CCR3 cDNA sequence and investigation of the localization of CCR3 mRNA expression in horse tissues. Equine CCR3 displayed high levels of sequence identity with CCR3 sequences in other species. RT-PCR analysis revealed the expression of CCR3 in colon, lung and spleen of normal horses. In situ hybridisation experiments indicated that expression of CCR3 mRNA in colon was predominantly in eosinophils and to a lesser extent in mast cells, whereas CCR3 was seen mainly in lymphocytes of the lung and spleen. In view of the role of CCR3 in the recruitment of cells into sites of allergic inflammation, equine-specific CCR3 sequence data and information on tissue localization will be of potential benefit in the development of CCR3-targeted anti-inflammatory therapies in the horse.     

Integrated assessment of catchment suspended sediment budgets: a Zambian example

In many developing countries, the management of sediment‐related environmental problems is severely hampered by a lack of information on sediment mobilization and delivery in river basins. The sediment budget concept represents a valuable framework for assembling such information, which can, in turn, be used to assist with the design and implementation of soil erosion and sediment control policies. However, the information necessary to construct a catchment sediment budget is difficult to assemble. Against this background, an integrated approach to establishing a catchment suspended sediment budget, involving a river monitoring station, the use of ¹³⁷Cs measurements to estimate soil erosion and deposition and floodplain accumulation rates within the catchment, and sediment source fingerprinting, has been developed and tested in the 63 km² catchment of the upper Kaleya River in southern Zambia. The approach developed not only provides detailed information on individual components of the suspended sediment delivery system, but also permits the establishment of the overall catchment sediment budget. A sediment budget for the upper Kaleya catchment is presented and both its key features and its wider implications for catchment management are discussed. Copyright © 2001 John Wiley & Sons, Ltd.