http://cadair.aber.ac.uk/dspace The DSpace digital repository system captures, stores, indexes, preserves, and distributes digital research material. Search the Channel search http://cadair.aber.ac.uk/dspace/simple-search http://hdl.handle.net/2160/4136 Title: Integration, expression and inheritance of transgenes in hexaploid oats (Avena sativa L.)<br/><br/>Authors: Perret, Sophie J.; Valentine, John; Leggett, J. Michael; Morris, Phillip<br/><br/>Editors: <br/><br/>Abstract: Two oat varieties, Melys (spring variety) and Bulwark (winter variety) were transformed by particle bombardment of primary embryogenic callus using either a ubi-bar-ubi-gus co-integration vector or co-transformed (Melys) with a ubi-bar plasmid together with one of three plasmids containing the β-glucuronidase (gus) gene under the control of either a rice actin promoter, a CaMV35S promoter or a wheat high molecular weight glutenin promoter. Morphologically normal and fertile transgenic plants were regenerated following callus selection with glufosinate ammonium. Evidence for the integration and functioning of the selectable (bar) and reporter (gus) genes in To and T1 plants was confirmed by PCR, Southern hybridisation, fluorescence in situ hybridisation (FISH), histochemical assays, and by progeny analysis. Transformation rates varied from 0.2 to 5.0 lines/plate of callus bombarded, with co-transformation frequencies of 83 to 100 percnt;, and co-expression frequencies of 60 to 100 percnt;. Copy numbers for the bar and gus gene varied from 3 to 17 and from 2 to 20 respectively. Cell and tissue specific expression of the gus gene was evident from the different promoters, with the HMW glutenin promoter showing endosperm specific expression in T1 seed. No expression of the gus gene under the CaMV35S promoter was detected in any tissues. Progeny analysis provided evidence of Mendelian inheritance of the introduced genes suggesting either one or two unlinked integration sites. This was confirmed by fluorescence in situ hybridisation to chromosome spread preparations. No segregation of the gus gene from the bar gene was observed in any of the progeny derived from co-transformation. Mon, 01 Mar 2010 17:09:27 GMT http://hdl.handle.net/2160/4135 Title: Plant enzyme mediated lipolysis of Lolium perenne and Trifolium pratense in an in vitro simulated rumen environment<br/><br/>Authors: Lee, Michael R. F.; Martinez, E. M.; Scollan, Nigel D.<br/><br/>Editors: <br/><br/>Abstract: This issue of Aspects of Applied Biology contains papers presented at the AAB conference on Crop quality and its importance for sustainable livestock production, held at the Manchester Conference Centre on 15-16 December 2003. The papers include general overviews concerning the future direction and priorities in forage crop breeding, as well as grassland and livestock research and knowledge transfer for developing profitable livestock systems with a more positive impact on the environment and biodiversity, and high quality food products for the consumer. Other papers deal more specifically with the genetic basis of quality traits in plants and progress towards the development of forage crops with improved quality traits, but also opportunities and challenges in developing forage crops for alternative uses such as fibres and biodegradable polymers. The remaining topics concern the impact on environment and biodiversity of different grassland management systems, research priorities for ruminant nutrition and improving the productive efficiency of grazing animals.<br/><br/>Description: Proceedings 'Crop Quality: Its role in sustainable livestock production', Association of Applied Biologists Conference, Manchester, 15-16 December 2003. Mon, 01 Mar 2010 17:04:01 GMT http://hdl.handle.net/2160/4134 Title: Assimilate partitioning in leaves of the raffinose-storing herb Lamium album L.: the effects of altering source-sink balance<br/><br/>Authors: Kochhar, Anu; ap Rees, Tom; Pollock, Chris J.<br/><br/>Editors: <br/><br/>Abstract: In Lamium album, sucrose and raffinose-family oligosaccharides are the major products of photosynthesis that are stored in leaves. Using gas analysis and 14CO2 feeding, we compared photosynthesis and the partitioning of recently-fixed carbon in plants where sink activity was lowered by excision of flowers and chilling of roots with those where sink activity was not modified. Reduction in sink activity led to a reduction in the maximum rate of photosynthesis, to retention of fixed carbon in source leaves and to the progressive accumulation of raffinose-family oligosaccharides. This ultimately affected the extractable activities of invertase and sucrose phosphate synthase. At the end of the light period, invertase activity was significantly higher in treated plants. By contrast sucrose phosphate synthase activity was significantly lower in treated plants. We propose that reducing sink activity in L. album is associated with a shift in metabolism away from starch and sucrose synthesis and towards sucrose catabolism, galactinol utilisation and the synthesis of raffinose-family oligosaccharides. Mon, 01 Mar 2010 16:59:26 GMT http://hdl.handle.net/2160/4133 Title: Nutritive quality QTL and marker assisted selection in ryegrass<br/><br/>Authors: Humphreys, Mervyn O.; Turner, Lesley B.<br/><br/>Editors: <br/><br/>Abstract: International Symposium on Grass BreedingMeeting of the EUCARPIA Section Fodder Crops and Amenity Grasses, 22-25 September 2002, Bundesforschungsanstalt für Landwirtschaft (FAL) Braunschweig, Germany.Editors: U.K. Posselt and J.M. Greef Published in: Vorträge für Pflanzenzüchtung, Issue 59 (ISSN 0723-7812), 2003.<br/><br/>Description: Proceedings of the International Symposium on Grass Breeding. 24th EUCARPIA Fodder Crops and Amenity Grasses Section, FAL, Braunschweig, Germany, 22-25 September 2002. Mon, 01 Mar 2010 16:54:36 GMT http://hdl.handle.net/2160/4132 Title: Do green plants age and, if so, how?<br/><br/>Authors: Thomas, Howard<br/><br/>Abstract: Time-dependent ageing-like processes in green plants are discussed and compared to gerontological changes in animals and other organisms. The question of plant ageing is inseparable from the issue of the developmental architecture of plants. Modular structure and fractal, recursive patterns of plant development mean that the concept of an individual, and hence of whole-organism ageing, is ambiguous. Selective disposal of cells, tissues and organs, a major determinant of perenniality and hence lifespan, is a morphogenetic and adaptive tool that superficially resembles, but is fundamentally different from, ageing. The contrast between autotrophs and heterotrophs in the relation between resource acquisition and allocation is discussed, particularly partitioning between reproductive and vegetative development. Genetic, environmental, and epigenetic factors influencing ageing-like behaviour, including senescence, stress responses, somatic mutation and phase change, are considered. Finally, mechanisms are proposed for the origin of ageing as an intrinsic property of living cells. Mon, 01 Mar 2010 16:48:14 GMT http://hdl.handle.net/2160/4131 Title: The repeatability of superovulatory response and embryo recovery in sheep<br/><br/>Authors: Bari, F.; Khalid, M.; Wolf, Basil; Haresign, William; Murray, A.; Merrell, B.<br/><br/>Editors: <br/><br/>Abstract: Over an 8-year period, a total of 328 Scottish Blackface donor ewes were involved in a MOET program. They were synchronized with fluorogestone acetate sponges and superovulated with ovine FSH. After the onset of estrus, ewes were hand-mated and laparoscopic artificial insemination was performed with fresh semen 44–46 h after sponge removal. Embryos were recovered semi-laparoscopically on either Day 5 or Day 6 after insemination. Of the 328 donor ewes used, 222 ewes were supervoulated only once, while the remaining ewes were superovulated either twice (73 ewes), 3 times (26 ewes) or 4 times (7 ewes) at yearly intervals to generate a maximum of 474 records for subsequent analysis. There was no significant change in either mean ovulation rate or the mean number of embryos recovered per donor ewe at successive treatments. However, significant (P < 0.05 at least) effects of both year and donor ewe age existed for superovulatory response and number of embryos recovered, though only the effect of year was significant (P < 0 001) for percentage (r = 0.55, s e. 0.055) and number of embryos recovered (r = 0.38, SE 0.074), but not for percentage embryo recovered (r = 0.04, SE 0.102). Mon, 01 Mar 2010 16:34:25 GMT http://hdl.handle.net/2160/4130 Title: Designing grasses with a future - combining the attributes of Lolium and Festuca<br/><br/>Authors: Thomas, Huw Martin; Morgan, W. Gareth; Humphreys, Mike W.<br/><br/>Editors: <br/><br/>Abstract: Lolium species (considered the ideal grasses for European agriculture) are not sufficiently robust to meet many of the environmental challenges that face extensive agriculture in less favoured areas. Fortunately, adaptations to abiotic and biotic stresses exist amongst Festuca species related closely to Lolium. The complex of species has an enormous wealth of genetic variability and potentiality for genetic exchange, thus offering unique opportunities for the production of versatile hybrid varieties with new combinations of useful characters suited to modern grassland farming. The attributes of Lolium and Festuca can be combined into a single genotype by amphiploidy or alternatively, a limited number of characters can be selectively introgressed from Festucainto Lolium or vice versa. Androgenesis of the interspecific hybrids can generate genotypes combining characters that may not be recovered by sexual backcrossing. Genomic in situ hybridization(GISH) can differentially ‘paint’ the chromosomes of Lolium and Festuca and identify Lolium-Festuca recombinant chromosomes. GISH is valuable in the analysis of amphiploids, introgressions and androgenic genotypes and can be used to physically map introgressed traits. Introgression mapping is a powerful new approach to the mapping of traits and arises from a fusion of physical and genetic mapping. For example, in a diploidLolium introgression genotype with only one introgressed Festucasegment, the gene(s) for any Festucaderived trait expressed by the plant must be located within the segment. Using GISH and molecular markers, a dense but highly localised map of the Festuca segment is made in isolation of the Loliumgenome – this may simplify QTL analysis. Mon, 01 Mar 2010 16:19:18 GMT http://hdl.handle.net/2160/4129 Title: Restriction Fragment Length Polymorphism Analysis of Ribosomal DNA Intergenic Regions Is Useful for Differentiating Strains of Trichophyton mentagrophytes<br/><br/>Authors: Mochizuki, Takashi; Ishizaki, Hiroshi; Barton, Richard C.; Moore, Mary K.; Jackson, Colin J.; Kelly, Steven L.; Evans, E. Glyn<br/><br/>Editors: <br/><br/>Abstract: Twenty isolates of Tricophyton mentagrophytes var. mentagrophytes and 47 isolates of T. mentagrophytes var. interdigitale, identified by morphological characteristics, were screened by restriction fragment length polymorphism (RFLP) analysis of the PCR-amplified internal transcribed spacer (ITS) region of ribosomal DNA (rDNA). Sixty isolates (14 of 20 T. mentagrophytes var. mentagrophytes isolates and 46 of 47 T. mentagrophytes var. interdigitale isolates) shared an identical ITS RFLP profile and were further investigated by using a probe targeted to the rDNA nontranscribed spacer (NTS) region. Polymorphisms were observed in the NTS regions of both T. mentagrophytes var. mentagrophytes and T. mentagrophytes var. interdigitale isolates. Twenty-three individual RFLP patterns (DNA types P-1 to P-12 and A-1 to A-11) were recognized and divided into two groups depending on the presence (P) or absence (A) of a 2.5-kb band, which correlated to a large extent with the morphological variety. Eleven of 14 T. metagrophytes var. mentagrophytes isolates were A types, and all of the 46 T. mentagrophytes var. interdigitale isolates were P types. A majority of strains (23 of 60 [38.3%]) were characterized by one RFLP pattern (pattern P-1), and eight types (P-1 to P-6, P-8, and P-9) accounted for 75% (45 of 60) of all strains, including all of the T. mentagrophytes var. interdigitale isolates. The remaining 15 types were represented by one only isolate and included all of the T. mentagrophytes var. mentagrophytes isolates. We conclude that RFLP analysis of the rDNA NTS region is a valuable technique for differentiation of T. mentagrophytes strains. Furthermore, by use of this method, there appears to be a greater degree of diversity among T. mentagrophytes var. mentagrophytes isolates than among T. mentagrophytes var. interdigitale isolates. Mon, 01 Mar 2010 16:13:56 GMT http://hdl.handle.net/2160/4128 Title: Chlorophyllase activity and chlorophyll content in wild type and eti 5 mutant of Arabidopsis thaliana subjected to low and high temperatures<br/><br/>Authors: Todorov, D.T.; Karanov, E.N.; Smith, Aileen R.; Hall, M.A.<br/><br/>Editors: <br/><br/>Abstract: Chlorophyll a (Chl a) content and chlorophyllase (Chlase) activity from leaves of wild type (WT) and the ethylene-insensitive mutant (eti 5) of Arabidopsis thaliana (L.) Heynh during temperature stress and plant recovery have been studied. The plants were subjected to temperatures of 4 °C (LT) and 38 °C (HT) for 24 h. Chl a gradually decreased somewhat during stress and in the first day of recovery, especially in HT-treated plants. At the end of the experimental period (1 d stress and 10 d recovery) Chl a content was lower in eti 5 plants than in WT ones. The Chlase in WT was more affected than in eti 5 plants during the temperature treatment and the recovery period. Mon, 01 Mar 2010 16:09:02 GMT http://hdl.handle.net/2160/4127 Title: Use of principal component analysis to investigate the origin of heptadecenoic and conjugated linoleic acids in milk.<br/><br/>Authors: Fievez, V.; Vlaeminck, B.; Dhanoa, M. S.; Dewhurst, Richard J.<br/><br/>Editors: <br/><br/>Abstract: The aim of this paper was the application of principalcomponent analysis (PCA) 1) to elucidate mutual metabolicrelationships between milk fatty acids (FA) and2) to illustrate the origin of milk FA, in particular C17:1and cis-9,trans-11 conjugated linoleic acid. Data werecombined from 3 experiments with lactating Holstein-Friesian cows offered diets based on grass or legumesilage and concentrates. Loading plots of PCA based onmilk FA concentrations showed 4 groups of milk FA,having similar precursors or metabolic pathways in therumen and/or mammary gland: medium-chain saturatedFA, de novo synthesized from acetate and β-hydroxybutyrate;monoenoic milk FA, products of Δ9-desaturaseactivity in the mammary gland; odd chain FAof rumen microbial origin and C18:0, n-6 C18:2, and n-3C18:3 of dietary origin or the result of rumen biohydrogenation.Loading plots of PCA based on both milk andduodenalFAconcentrations as well as on milkFAyieldsand duodenal FA flows further illustrated the importanceof postabsorptive synthesis of the milk mediumchain saturated and monoenoic FA and the direct absorptionfrom the blood stream of odd chain FA, C18:0,n-6 C18:2, and n-3 C18:3. In all loading plots, milk oleicacid (C18:1) appeared intermediate between clusters of18-carbon FA and monoenoic FA, illustrating its dual(dietary and endogenous production) origin. Milk C17:1was suggested to be a desaturation product of C17:0, incommon with other milk monoenoic FA. Finally, thePCA technique, based on milk FA patterns of one experiment,was applied to investigate factors determiningcis-9,trans-11 conjugated linoleic acid concentrations inmilk. Within the range of diets and cows studied here,we showed changes in cis-9,trans-11 conjugated linoleicacid to be mainly dependent on vaccenic acid supply andto a lesser extent on variation in desaturase activity. Mon, 01 Mar 2010 10:08:00 GMT http://hdl.handle.net/2160/4126 Title: Investigation of the molecular mechanisms of itraconazole resistance in Candida dubliniensis<br/><br/>Authors: Pinjon, Emmanuelle; Moran, Gary P.; Jackson, Colin J.; Kelly, Steven L.; Sanglard, Dominique; Coleman, David C.; Sullivan, Derek J.<br/><br/>Editors: <br/><br/>Abstract: It has previously been shown that overexpression of the CdMDR1 gene is a major contributor to resistance in fluconazole-resistant isolates of Candida dubliniensis. However, since CdMdr1p does not mediate transport of other azole drugs such as itraconazole, we investigated the molecular mechanisms of stable resistance to itraconazole obtained in three strains of C. dubliniensis (two with nonfunctional CdCDR1 genes and one with functional CdCDR1 genes) by serial exposure to this antifungal agent in vitro. Seven derivatives that were able to grow on agar medium containing 64 µg of itraconazole per ml were selected for detailed analysis. These derivatives were resistant to itraconazole, fluconazole, and ketoconazole but were not cross resistant to inhibitors. CdMDR1 expression was unchanged in the seven resistant derivatives and their parental isolates; however, all seven derivatives exhibited increased levels of CdERG11 expression, and six of the seven derivatives exhibited increased levels of CdCDR1 expression compared to the levels of expression by their respective parental isolates. Except for one derivative, the level of rhodamine 6G efflux was decreased in the itraconazole-resistant derivatives compared to the level of efflux in their parental isolates, suggesting altered membrane properties in these derivatives. Analysis of their membrane sterol contents was consistent with a defective sterol C5,6-desaturase enzyme (CdErg3p), which was confirmed by the identification of mutations in the alleles (CdERG3) encoding this enzyme and their lack of functional complementation in a Saccharomyces cerevisiae erg3 mutant. The results of this study show that the loss of function of CdErg3p was the primary mechanism of in vitro-generated itraconazole resistance in six of the seven the C. dubliniensis derivatives. However, the mechanism(s) of itraconazole resistance in the remaining seventh derivative has yet to be determined. Mon, 01 Mar 2010 10:03:30 GMT http://hdl.handle.net/2160/4125 Title: Forage quality of Trifolium repens L. x T. nigrescens Viv. hybrids<br/><br/>Authors: Marshall, Athole H.; Abberton, Michael T.; Williams, T. Andy; Michaelson-Yeates, Terry P. T.; Powell, Huw G.<br/><br/>Editors: <br/><br/>Abstract: Interspecific hybridization with the close relative Trifolium nigrescens Viv. (Ball clover) is a possible strategy to increase the seed yield potential of white clover (T. repens L.). Fertile F1 plants have been used as the basis for several generations of backcrossing using T. repens as the recurrent parent. Forage quality of the parental species and backcross hybrids when grown in mixtures with perennial ryegrass (Lolium perenne L.) was compared in field plots over three harvest years. The dry-matter digestibility (DMD) and crude protein (CP) concentration of the legume fraction was greater than that of perennial ryegrass, but the water-soluble carbohydrate (WSC) concentration of the legume components was lower than that of perennial ryegrass. Differences in forage quality between T. repens and the backcross hybrids were relatively small. The WSC concentration of the backcrosses was less than T. repens but the CP concentration was greater. Significant differences in the forage quality of the companion grass were observed when grown with the parental species and the hybrids; however, these differences were attributed to the plots with T. nigrescens and the F1 plants, where the clover content was low. Few differences in the forage quality of the grass were measured when grown with T. repens and the backcross hybrids. The impact of these results on the use of these hybrids in cultivar development programmes is discussed. Mon, 01 Mar 2010 09:58:09 GMT