Epidemic of blindness in kangaroos - evidence of a viral aetiology     

PT HOOPER  RA LUNT  AR GOULD  AD HYATT  GM RUSSELL  JA KATTENBELT  SD BLACKSELL  LA REDDACLIFF  PD KIRKLAND  RJ DAVIS  PJK DURHAM  AL BISHOP  J WADDINGTON 《Australian veterinary journal》1999,77(8):529-536

OBJECTIVE: To determine the cause of an epidemic of blindness in kangaroos. DESIGN AND PROCEDURES: Laboratory examinations were made of eyes and brains of a large number of kangaroos using serological, virological, histopathological, electron microscopical, immunohistochemical methods, and PCR with cDNA sequencing. In addition, potential insect viral vectors identified during the disease outbreak were examined for specific viral genomic sequences. SAMPLE POPULATION: For histopathological analysis, 55 apparently blind and 18 apparently normal wild kangaroos and wallabies were obtained from New South Wales, Victoria, South Australia, and Western Australia. A total of 437 wild kangaroos and wallabies (including 23 animals with apparent blindness) were examined serologically. RESULTS: Orbiviruses of the Wallal and Warrego serogroups were isolated from kangaroos affected with blindness in a major epidemic in south-eastern Australia in 1994 and 1995 and extending to Western Australia in 1995/96. Histopathological examinations showed severe degeneration and inflammation in the eyes, and mild inflammation in the brains. In affected retinas, Wallal virus antigen was detected by immunohistochemical analysis and orbiviruses were seen in electron microscopy. There was serological variation in the newly isolated Wallal virus from archival Wallal virus that had been isolated in northern Australia. There were also variations of up to 20% in genotype sequence from the reference archival virus. Polymerase chain reactions showed that Wallal virus was present during the epidemic in three species of midges, Culicoides austropalpalis, C dycei and C marksi. Wallal virus nucleic acid was also detected by PCR in a paraffin-embedded retina taken from a blind kangaroo in 1975. CONCLUSION: Wallal virus and perhaps also Warrego virus are the cause of the outbreak of blindness in kangaroos. Other viruses may also be involved, but the evidence in this paper indicates a variant of Wallal virus, an orbivirus transmitted by midges, has the strongest aetiological association, and immunohistochemical analysis implicates it as the most damaging factor in the affected eyes.  相似文献   

Hierarchically ordered oxides     

P Yang  T Deng  D Zhao  P Feng  D Pine  BF Chmelka  GM Whitesides  GD Stucky 《Science (New York, N.Y.)》1998,282(5397):2244-2246

Porous silica, niobia, and titania with three-dimensional structures patterned over multiple length scales were prepared by combining micromolding, polystyrene sphere templating, and cooperative assembly of inorganic sol-gel species with amphiphilic triblock copolymers. The resulting materials show hierarchical ordering over several discrete and tunable length scales ranging from 10 nanometers to several micrometers. The respective ordered structures can be independently modified by choosing different mold patterns, latex spheres, and block copolymers. The examples presented demonstrate the compositional and structural diversities that are possible with this simple approach.  相似文献   

Effect of high hydrostatic pressure on the volatile components of a glucose-lysine model system.   总被引：1，自引：0，他引：1  

V M Hill  N S Isaacs  D A Ledward  J M Ames 《Journal of agricultural and food chemistry》1999,47(9):3675-3681

An aqueous glucose-lysine model system (initial pH 10.1) was incubated at 60 degrees C and atmospheric pressure (system A) or 600 MPa (system B) to the same absorbance value at 420 nm. Volatile reaction products were isolated by solvent extraction and analyzed by gas chromatography/mass spectrometry. Thirty-two compounds were identified; most contained nitrogen, and pyrazines predominated. Yields of all compounds were suppressed at 600 MPa. Further incubation, at either atmospheric pressure (system C) or 600 MPa (system D), of system A, resulted in lower yields of many compounds at 600 MPa, compared to prolonged incubation at atmospheric pressure. Many of the compounds reported may be formed by, or subsequently react via, aldol condensation. The observed differences among the systems in the profiles and yields of volatile compounds suggest that aldol condensations increase in rate in the systems under pressure.  相似文献   

SEED PRODUCTION STUDIES ON PERENNIAL RYEGRASS, TIMOTHY AND PRAIRIE GRASS     

M. J. Hill  B. R. Watkin 《Grass and Forage Science》1975,30(1):63-71

A study over two years involving tiller identifica tion according to month of origin enabled the contribution of individual tillers of perennial rye grass Grasslands Ruanui, timothy Grasslands Kathu and a local New Zealand strain of prairie grass (Bromus unioloides) to be determined at seed harvest. In addition, the distribution of seed-heads in different arbitrary emergence groups was detemined so as to allow analysis of individual seedhead components within each group. In all species, tillers formed during the first 4 months following an autumn sowing in the first year, and also in the immediate post-harvest period and through the autumn in the second year, made a major contribution to seedhead numbers and seed yield at harvest. These tillers had a lower vegetative mortality rate than those formed in the spring. Primary tillers formed after sowing were highly persistent and became almost exclusively repro ductive. Many vegetative tillers died before har vest, behaving as annual tillers. Spring-formed tillers made a major contribution to the vegetative growth of the plant over the summer and early autumn. These tillers generally died before the following winter. Tillers formed in winter and early spring by ryegrass and prairie grass showed a high mortality, particularly in the second year. In timothy, mortality was highest amongst tillers formed in late spring. The reduced contribution of spring-formed tillers to the seed head population occurred as a result of fewer heads numerically compared with older tillers. In all species, most seedhead components varied according to time of ear emergence. Early emerged heads were generally longer, bore more spikelets and more florets per head and had a greater culm length than late-emerged heads. The major trend in all species was a general depression in head length, spikelet and floret number and culm length with grazing. These effects were in most cases partly or completely overcome by N application. The major effect of applied N was to increase floret number per head.  相似文献   

Chromatograms of foods for multicomponent residue determination of pesticides containing phosphorus and-or sulfur by GLC with flame photometric detection     

M C Bowman  M Beroza  K R Hill 《Journal of the Association of Official Analytical Chemists》1971,54(2):346-358

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The Zone of Localization of Anti-Mouse-Kidney Serum as Determined by Radioautographs     

Pressman D  Hill RF  Foote FW 《Science (New York, N.Y.)》1949,109(2821):65-66

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Further observations on “blue stem” of potato     

C. R. Orton  L. M. Hill 《American Journal of Potato Research》1938,15(3):72-77

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Comparing different multivariate calibration methods for the determination of soil organic carbon pools with visible to near infrared spectroscopy   总被引：1，自引：0，他引：1  

Michael Vohland  Joachim Besold  Joachim Hill  Heinz-Christian Fründ 《Geoderma》2011,166(1):198-205

A successful determination of spectrally active soil components with visible and near infrared reflectance spectroscopy (VIS-NIRS, 400-2500 nm) depends on the selection of an adequate multivariate calibration technique. In this study, the contents of thermolabile organic carbon (C_375 °C), the inert organic C fraction (C_inert) and the sum of both (total soil organic carbon, OC_tot) were estimated with three different methods: partial least squares regression (PLSR) as common standard tool, a combination of PLSR with a genetic algorithm (GA-PLSR) for spectral feature selection, and support vector machine regression (SVMR) with non-linear fitting capacities. The objective was to explore whether these methods show differences concerning their ability to predict soil organic carbon pools from VIS-NIR data. For this analysis, we used both measured spectra and also spectra successively blurred with uniformly distributed white noise. Soil sampling was performed in a floodplain (grassland plots) near Osnabrück (Germany) and comprised a total of 149 samples (109 calibration samples, 40 validation samples); spectral readings were taken in the laboratory with a fibre-optics ASD FieldSpec II Pro FR spectroradiometer.In the external validation, differences between the calibration methods were rather small, none of the applied techniques emerged to be the fittest with superior prediction accuracies. For C_375 °C and OC_tot, all approaches provided reliable estimates with r² (coefficient of determination) greater than 0.85 and RPD values (defined as ratio of standard deviation of measurements to standard error of prediction) greater than 2.5. For C_inert, accuracies dropped to r² < 0.50 and RPD < 1.5; after the removal of two extreme values (n = 38) results improved at best (GA-PLSR) to r² = 0.80 and RPD = 1.98. The noise experiment revealed different responses of the studied approaches. For PLSR and GA-PLSR, increasing spectral noise resulted in successively reduced r² and RPD values. By contrast, SVMR kept high coefficients of determination even at high levels of noise, but increasing noise caused severely biased estimates, so that regression models were less accurate than those of PLSR and GA-PLSR.  相似文献   

Sorption behavior of mixtures of glycerol and starch     

Enrione JI  Hill SE  Mitchell JR 《Journal of agricultural and food chemistry》2007,55(8):2956-2963

Glycerol is often added to starches to plasticize the product, but the presence of glycerol may also affect the water content of the samples. To evaluate the effect of glycerol on the sorption properties of starches, waxy maize, rice, and wheat starch were thermomechanically extruded in the presence of glycerol. Sorption isotherms of these extruded samples were ascertained using dynamic vapor sorption (DVS). BET and GAB modeling showed a monolayer (mo) significantly higher for waxy maize than for rice and wheat. Glycerol inclusion changed the model values, indicating reduction in sorption energy at the monolayer and restructuring of the multilayer. An interaction factor (xi) based on weight fraction models was calculated. Differences in xi were obtained when glycerol was added, varying from approximately 0.9 for 5% glycerol to approximately 0.8 for 20% glycerol, supporting the hypothesis of interactions between starch and this polyol.  相似文献   

Bovine sire selection based on maintenance energy affects muscle fiber type and meat color of F1 progeny     

Thornton KJ  Welch CM  Davis LC  Doumit ME  Hill RA  Murdoch GK 《Journal of animal science》2012,90(5):1617-1627

A total of 42 F(1) Red Angus progeny from sires divergent in maintenance energy (ME(M)) EPD were analyzed to determine whether selecting for sire ME(M) would alter end-product meat quality. Data from animals were grouped based on the divergence of the ME(M) EPD of their sire from the Red Angus Association-reported breed average and defined as either high or low, the assumption being that high-ME(M) cattle are less efficient because their maintenance requirements represent a larger proportion of their dietary intake. Steer progeny (n = 7) from the high group produced bottom round steaks with a greater a* (redness) color value (P = 0.02) after 5 d in a simulated retail display when compared with bottom round steaks from the low group (n = 18). Bottom round steaks from the high group had a greater b* (yellowness) color value at d 1 (P = 0.03) and d 5 (P = 0.01) of retail display. Samples from the biceps femoris were taken at 12 mo (from both steers and heifers) and 15 mo (from steers only) of age for fiber type proportion analysis. At 12 mo of age, steers from the low group had more type I fibers (P = 0.02), whereas steers from the high group had more type IIb fibers (P = 0.01). Furthermore, samples from steers in the low group at 15 mo had more type I fibers (P = 0.02), and steers from the high group maintained more type IIb fibers (P = 0.02). No changes in fiber type proportions were observed between the high- and low-ME(M) EPD heifers (n = 17). Relative mRNA abundance of genes involved in the synthesis, storage, and breakdown of glycogen were analyzed as a variable important for meat quality, but no statistical differences were observed. At 12 mo age, glycogenin (glyc) was negatively correlated with the proportion of type IIa fibers (r = -0.32 and P = 0.12) as well as with the proportion of type IIb fibers (r = -0.42 and P = 0.03) in the biceps femoris of the steers. In samples taken from the biceps femoris at 15 mo age, glyc was negatively correlated with the proportion of type IIa fibers (r = -0.42 and P = 0.03) in the steers. This indicates that relative mRNA expression of glyc may serve as a marker of muscle glycogen storage capacity in steers. Thus, selection for efficient Red Angus beef cattle based on sire ME(M) EPD does not adversely affect meat quality in F(1) progeny, based on the variables assessed in this study. Furthermore, selection for progeny from low-ME(M) EPD sires may improve fresh meat quality within Red Angus beef cattle.  相似文献