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41.
Monkeys injected with monkey retinal tissue incorporated in Freunld's complete adjuvant developed ocular lesions characterized by choroiditic patches in the fundus periphery and sheathing of retinal vessels. Bovine retina, monkey choroid plexus, and guinea pig kidney were ineffective in this respect.  相似文献   
42.
Antibodies that react with predetermined sites on proteins   总被引:23,自引:0,他引:23  
Contrary to previous predictions, relatively short synthetic peptides that mimic part of a protein sequence are routinely capable of eliciting an antiserum that reacts with the partially mimicked protein. Peptides capable of eliciting protein-reactive serums are frequently represented in the primary sequence of a protein, can be characterized by a set of simple chemical rules, and are confined neither to immunodominant regions of intact proteins nor to the amino or carboxyl terminals. As such, synthetic peptide immunogens are valuable for eliciting reagents with predetermined specificity that can be used for basic research. In addition, some synthetic peptides are capable of mimicking regions of virus proteins and eliciting immune responses in animals that are protective against the viral agents. Such peptides may thus serve as the basis for safe, chemically defined synthetic vaccines.  相似文献   
43.
The RNP and Sm antigens recognized by lupus erythematosus antibodies are located on discrete particles containing single small nuclear RNA's complexed with proteins. The antigens Ro and La are also on ribonucleoproteins. The small RNA's in ribonucleoproteins with Ro are discrete, like those associated with RNP and Sm; in contrast, ribonucleoproteins with La contain a striking highly banded spectrum of small RNA's from uninfected cells as well as virus-associated RNA from adenovirus-infected cells.  相似文献   
44.
CASE HISTORY: A skeletal disease characterised by dwarfism, limb deformity and sometimes sudden death occurred over a period of 5 years in lambs born on a commercial sheep farm in Southland. The disease showed variable expression and occurred in crossbred sheep. A genetic aetiology was supported by the birth of affected lambs over two seasons in a flock of putative carrier and affected sheep transported to Massey University.

CLINICAL FINDINGS: Affected lambs appeared normal at birth but showed evidence of dwarfism, wide-based stance and exercise intolerance as early as 1 week of age. Most died within the first 3 months of life, often after developing bilateral varus deformity of the forelimbs. Some severely-affected lambs died suddenly of respiratory embarrassment, probably due to tracheal collapse. Mildly-affected individuals had a short, blocky stature and some survived to breeding age.

PATHOLOGICAL FINDINGS: Gross and microscopic lesions of variable severity were present in the tracheal, articular, epiphyseal and physeal cartilages. In severe cases, articular cartilage in major joints was eroded from weight-bearing surfaces. The trachea was flaccid, abnormally kinked, and had thickened cartilaginous rings and a narrow lumen. Affected sheep that survived to breeding age eventually developed severe degenerative joint disease. Histologically, chondrocytes were disorganised, surrounded by concentric rings of abnormal fibrillar material, and the matrix often contained focal to coalescing areas of chondrolysis.

DIAGNOSIS: Inherited chondrodysplasia of Texel sheep.

CLINICAL RELEVANCE AND CONCLUSIONS: This chondrodysplasia differs from those previously described in sheep and is considered to be a newly-recognised, recessively-inherited genetic disease of the Texel breed. A defect in the synthesis of glycosaminoglycans in cartilage matrix is suspected. This disease of sheep may provide a suitable model for studying various forms of therapy for human chondrodysplasias.  相似文献   
45.
Inherited rickets of Corriedale sheep is of simple autosomal recessive inheritance. The gross and histological lesions include segmental thickening of physes, persistence of hypertrophic chondrocytes at sites of endochondral ossification, excessive osteoclastic resorption, microfractures and wide unmineralised osteoid seams lining trabeculae and filling secondary osteons. Initial testing revealed concentrations of 25-hydroxyvitamin D3 were normal, but those of 1,25-dihydroxyvitamin D3 were increased in serum of affected sheep, suggesting a defect in the vitamin D receptor. However, in vitro studies on cultured skin fibroblasts revealed normal binding and function of the vitamin D receptor.

A genome-wide association study was conducted using the Illumina OvineSNP50 BeadChip. A homozygous region of 199 consecutive single-nucleotide polymorphism loci was identified in affected sheep, covering a region of 10 megabase pairs on ovine chromosome 6. Of the 91 candidate genes in this region, dentin matrix protein 1 gene (dmp1) was considered the most likely as it is known to play critical roles in osteocyte maturation and mineral metabolism. Sequencing of DNA from carriers showed a nonsense mutation 253T/C in dmp1. This T/C transition introduced a stop codon (R145X) that could truncate C-terminal amino acids. Using PCR restriction fragment length polymorphism for this mutation, genotyping showed that all affected sheep were “TT” genotypes, and phenotypically normal sheep were either “CT” or “CC”. These findings suggest that a mutation in dmp1 is responsible for inherited rickets of Corriedale sheep. A simple diagnostic test is currently being designed to identify carriers with the defective “T” alleles.  相似文献   
46.
Abstract

HISTORY: A similar episodic neurological disorder occurred in new born lambs on two unrelated properties involving disparate breeds of sheep. Because of the number of lambs born, cross-breeding and the fact it occurred in some mating groups and not others, a dominant mode of inheritance was, initially and separately, suspected in each case. The sires of affected lambs were apparently normal. Whereas one was New Zealand Romney, the other was a composite breed with East Friesian genetics, but both rams originated from the same source property. To investigate the pathogenesis of the disorder these two rams were acquired and mated with unrelated sheep, under experimental conditions in a more controlled environment.

CLINICAL FINDINGS: A proportion of lambs born to both sires exhibited a similar neurological disorder. Some lambs were noted to be abnormal at birth, both on home properties and in the experimental flock. They tended to adopt a head and neck extended posture and were slow to get to their feet and suckle when they then became more or less normal. When forced to move, they and other more robust lambs elicited an asymmetric gait, base-wide extensor hypertonia (hypometria) of thoracic limbs and flexor hypertonia (hypermetria) of pelvic limbs. In some there was nystagmus. After several metres of asymmetric ataxic gait they would fall to one side, sometimes adopting a sitting position. Recovery usually occurred in one to several minutes. As lambs aged, it became more difficult to elicit the episodes of dysfunction and by 6 months of age they appeared normal.

DIAGNOSIS: The disorder was diagnosed as a dominant familial episodic cerebellovestibular ataxia inherited as a dominant trait, with incomplete penetration of observed clinical signs and variable expressivity.

CLINICAL RELEVANCE: A proportion of affected lambs are likely to die in the neonatal period so the specific nature of the disorder may go unrecognised. Because of incomplete penetrance and varying expressivity, many of the lambs carrying this mutation will survive without showing clinical signs and may enter breeding flocks, where the disorder may be perpetuated and contribute to neonatal deaths.  相似文献   
47.
Most eucalypt plantations are managed in short rotations (6–8 years) and are established in regions with water and nutritional stresses of varying degrees. The mean annual increment in these regions ranges from 20 to 45 m3 ha?1 y?1 depending on the level of environmental stress. Improving natural resource use efficiency by breeding and matching genotypes to sites and using appropriate site management practices is a key challenge to sustain or increase productivity. Climate change is emerging as a driving force behind many of the current issues facing natural resources, and is likely to intensify the water constraint. The Intergovernmental Panel on Climate Change has predicted significant increases in surface air temperatures and decreases in rainfall (with more erratic rainfall patterns) over the tropics and subtropics, affecting drier regions in particular. To be truly sustainable, forest management practices must be environmentally friendly, prevent or reduce land degradation, improve biodiversity and increase resilience to climate variation and change. The main efforts should address the problems of water scarcity, low soil fertility and reduced biodiversity. Forest growers should take into account the inherent risks of different forest management systems on the regional water availability and consider reducing forest productivity in order to maintain both ecological and social equilibrium. The design and implementation of management techniques should be adapted to the specific production and protection objectives, which depend on the regional and local edaphoclimatic circumstances, water resources management, protection against soil erosion, diseases, pests, bushfires, strong winds and alien species. This paper addresses the basic requirements for integrating genetic and silvicultural strategies to minimise the water constraints in eucalypt plantations and surrounding water and native vegetation resources. We show several examples of effective forest management actions on the scale of forest stand and watershed in use in Brazil.  相似文献   
48.
The aim of this research was to determine the effect of nitrogen (N) availability on wild Rhizobiumnodulation, plant growth and grain yield of the common bean crop. Experiments were conducted in two growing periods, from 2 March to 3 June 2011 (autumn) and from 21 September to 23 December 2011 (spring), in pots using sand as substrate. Nitrogen concentrations of 5.12 (T1), 7.6 (T2), 10.12 (T3), 12.62 (T4), and 15.12 (T5) mmol L?1 were supplied by fertigation. In spring, the grain yield, number of grains and shoot growth of both cultivars reduced by effect of N concentration but in the cultivar BRS Valente they reducedonly in autumn. Number of nodules and root growth decreased in both cultivars while N concentration increased in the plant tissues. Nitrogen fertilization is not required to the common bean and its use inhibits nodulation. The increased availability does not enhance plant growth and grain yield.  相似文献   
49.
Rosmarinus officinalis L. (rosemary), is a medicinal and aromatic species used in the cosmetics and food processing industries. The present study aimed to evaluate the biomass production, content, yield and chemical composition of the essential oil of rosemary in cultivation out of soil with different concentrations of nutrient solution in both harvests. The cultivation of rosemary was conducted in a protected system off the ground, with concentrations of nutrient solutions of 1, 2, 3, 4 and 5 dS.m?1 for fertigation with collections of leaves 100 and 160 days after planting. Nutrient solution concentration influences phytomass production and the content and yield of essential oil of rosemary, though not its chemical composition. The collection time does not interfere in the content of essential oil; however, does interfere in the chemical composition; the production of phytomass and the yield of oil per plant are higher in collections at 160 days after planting.  相似文献   
50.
Major variables which determine the induction and severity of adoptive autoimmune encephalomyelitis are the age and strain of the animal, and the amount of killed mycobacteria in the adjuvant. Control of these factors results in consistent production of this disease in high incidence and in severe form. The pathologic changes in the central nervous system can be correlated with the clinical disease. Maturity of the target tissues in the central nervous system of the newborn appears to be an important factor which distinguishes the response of the guinea pig from that of other species.  相似文献   
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