Subcellular distribution of copper in the liver of fetal deer in the last month of gestation   总被引：2，自引：0，他引：2  

M J Leighton  T J Peters  R Hill  G D Smith  W Holt  D M Jones 《Research in veterinary science》1990,49(3):298-305

Fetal deer, in the last month of gestation, accumulate high concentrations of copper in the liver. Livers from fetal deer in late gestation were homogenised and fractionated by continuous sucrose density gradient centrifugation. The distribution of copper closely followed that of DNA; approximately two thirds of the metal was localised to the nuclear fractions with the remaining third in the cytosolic fractions. The fractionation procedure was repeated with digitonin, a lysosomal perturbant: lysosomes were disrupted and the marker enzyme, N-acetyl-beta-glucosaminidase, shifted from the particulate fractions to the cytosolic fractions; the distribution of copper was unaffected. Differential centrifugation of homogenate confirmed that approximately two thirds of the copper was associated with the nuclear fraction. Further confirmation of a nuclear localisation of copper was provided by X-ray microanalysis of purified nuclei.  相似文献   

Histologic and histochemical changes in articular cartilages of immature beagle dogs dosed with difloxacin, a fluoroquinolone   总被引：6，自引：0，他引：6  

J E Burkhardt  M A Hill  W W Carlton  J W Kesterson 《Veterinary pathology》1990,27(3):162-170

The histologic and histochemical features of quinolone-induced arthropathy were studied using 14 skeletally immature Beagle dogs (3 to 4 months old) dosed orally with difloxacin at 300 mg/kg body weight once daily for 1, 2, 5, or 7 days. A placebo was given to eight other age-matched Beagle dogs that served as controls. A scoring technique that included lesion size and histologic features was used to determine the progression of lesions. Articular-epiphyseal cartilage complexes on the femoral and humeral heads and tibial tarsal bone were identified as predilection sites. Within predilection sites on femoral and humeral heads, lesions developed in specific areas. Lesions appeared within 2 days of the onset of treatment, and lesion scores increased with time. Grossly, the lesions were raised, fluid-filled vesicles on the articular surface. Histologic changes included vesicle formation with loss of proteoglycan, clumping of unmasked collagen, and degeneration and necrosis of chondrocytes. In lesions with higher scores, chondrocytes were often in clusters or they were undergoing metaplasia toward spindle-shaped cells. Although dissolution of matrix and necrosis of chondrocytes were typical of all lesions, smaller lesions had histologically normal chondrocytes adjacent to small vesicles. In sections stained with toluidine blue, proteoglycan was aggregated with collagen fibrils or was absent from the matrix adjacent to vesicles. Unique features, such as biomechanical forces, may predispose specific areas of articular cartilage to develop lesions.  相似文献   

Morphological and molecular analysis of androgenetic, selfed and backcrossed plants produced from a Hordeum vulgare x H, bulbosum hybrid     

M. J. gilpin  R. A. pickering  A. G. fautrier  D. L. mcneil  G. szigat  A. M. Hill  R. G. Kynast 《Plant Breeding》1997,116(6):505-510

Anther culture (AC) was carried out on a fertile triploid hybrid between Hordeum vulgare L. (cultivated barley) and H. bulbosum L, (bulbous barley grass) to determine whether AC-derived regenerants differed from progeny obtained through selfing and backcrossing. Chromosome counts were carried out on all plants and DNA was extracted from them to prepare Southern blots for molecular analysis. To identify true recombinants, the blots were probed with rye repetitive sequence probes (pSc119.1 and pScl19.2). which hybridize strongly and specifically to H. bulbosum DNA. Twenty probes that detect single- or low-copy sequences were hybridized with Southern blots containing restricted DNA extracted from 25 AC-derived plants, 11 selfed and six backcrossed progeny that showed hybridizations with pScll9. Although restriction fragment length polymorphisms (RFLPs) were only observed using probes that map to four of the possible 14 chromosome arms, an introgression associated with chromosome 6HS was frequently observed among plants derived from AC. selfing and backcrossing. Plants from AC differed from selfed and backcrossed progeny in their chromosome number; unique RFLP bands that were occasionally observed may indicate chromosomal rearrangements.  相似文献   

Effects of Interspecific Competition on the Inheritance of Quantitative Traits in White Clover *)     

J. Hill 《Plant Breeding》1993,110(3):212-219

Analysis of a half diallel cross among four white clover cultivars, grown as monocultures and in mixtures (duocultures) with two separate perennial rye-grass cultivars, confirmed that for stolon and leaf number a higher proportion of the genetic variance in duocultures was non-additive. For canopy height and dry weight, however, this proportion was less affected by inter-specific competition. An additive-dominance model of gene action sufficed for all four characters in monocultures, but in duocultures epis-tasis was just one of the factors complicating the genetic picture. This, coupled with short-term reversals in the direction of dominance, merely illustrates the complexity of breeding white clover cultivars. Possible future developments in the breeding of white clover are discussed in the light of these results.  相似文献   

Improved plant heterokaryon formation by surfactant-supplementation of polyethylene glycol fusogen solution     

T. K. Hill  M. R. Davey  J. B. Power  P. Anthony  K. C. Lowe 《Euphytica》1995,85(1-3):269-273

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Biolistic introduction of a synthetic Bt gene into elite maize     

M. Hill  K. Launis  C. Bowman  K. McPherson  J. Dawson  J. Watkins  M. Koziel  M. S. Wright 《Euphytica》1955,85(1-3):119-123

Summary A synthetic Bt gene encoding a truncated version of the CryIA(b) protein derived from Bacillus thuringiensis was successfully introduced into elite maize using microprojectile bombardment of immature embryos. The method used to initiate and identify transformation events is described. We describe the detailed parameters used for the Biolistics device as well as the plasmids used for the transformations. The plasmids contained the synthetic Bt gene driven by either the 35S CaMV promoter or a combination of two tissue-specific promoters, leaf and pollen, derived from maize. Specific conditions for the culture of Type I callus from immature embryos, the phosphinothricin (PPT) selection protocol, and the regeneration of plants are discussed. T0 and T1 plants were initially identified using the pH-dependent chlorophenol red test and/or the histochemical -glucuronidase (GUS) assay. PCR and Southern data confirm the presence of the 35S CaMV promoter and the synthetic Bt gene.  相似文献   

Breeding components for mixture performance     

J. Hill 《Euphytica》1996,92(1-2):135-138

Summary The problems posed by breeding components for use in binary mixtures are discussed. Breeding and selection strategies designed to overcome some of these problems are outlined.  相似文献   

Temporal and spatial dynamics of soil solution C and N concentrations during Lolium perenne L. sward establishment and the effects of elevated CO₂ and N additions     

P.W. Hill  D.L. Jones  J.F. Farrar 《Soil biology & biochemistry》2006,38(6):1290-1297

There is now clear evidence for a prolonged increase in atmospheric CO₂ concentrations and enrichment of the biosphere with N. Understanding the fate of C in the plant-soil system under different CO₂ and N regimes is therefore of considerable importance in predicting the environmental effects of climate change and in predicting the sustainability of ecosystems. Swards of Lolium perenne were grown from seed in a Eutric Cambisol at either ambient (ca. 350 μmol mol⁻¹) or elevated (700 μmol mol⁻¹) atmospheric pCO₂ and subjected to two inorganic N fertilizer regimes (no added N and 70 kg N ha⁻¹ month⁻¹). After germination, soil solution concentrations of dissolved organic C (DOC), dissolved inorganic N (DIN), dissolved organic N (DON), phenolics and H⁺ were measured at five depths down the soil profile over 3 months. The exploration of soil layers down the soil profile by roots caused transient increases in soil solution DOC, DON and phenolic concentrations, which then subsequently returned to lower quasi-stable concentrations. In general, the addition of N tended to increase DOC and DON concentrations while exposure to elevated pCO₂ had the opposite effect. These treatment effects, however, gradually diminished over the duration of the experiment from the top of the soil profile downwards. The ambient pCO₂ plus added N regime was the only treatment to maintain a notable difference in soil solution solute concentration, relative to other treatments. This effect on soil solution chemistry appeared to be largely indirect resulting from increased plant growth and a decrease in soil moisture content. Our results show that although plant growth responses to elevated pCO₂ are critically dependent upon N availability, the organic chemistry of the soil solution is relatively insensitive to changes in plant growth once the plants have become established.  相似文献   

TWO LIMESTONE FORMATIONS OF THE CRETACEOUS OF TEXAS WHICH TRANSGRESS TIME DIAGONALLY     

Hill RT 《Science (New York, N.Y.)》1921,53(1365):190-191

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Rapid-cycling populations of brassica     

Williams PH  Hill CB 《Science (New York, N.Y.)》1986,232(4756):1385-1389

Rapid-cycling populations of six economically important species in the genus Brassica have unusual potential for resolving many problems in plant biology and for use in education. Rapid-cycling brassicas can produce up to ten generations of seed per year and serve as models for research in genetics, host-parasite relations, molecular biology, cell biology, plant biochemistry, population biology, and plant breeding. Brassicas are a highly diverse group of crop plants that have great economic value as vegetables and as sources of condiment mustard, edible and industrial oil, animal fodder, and green manure. These plants can also be used in the classroom as convenient, rapidly responding, living plant materials for "hands on" learning at all levels of our educational system.  相似文献