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71.
A bovine fecal Chlamydia, isolated from a clinically normal cow, had pathogenic capabilities and antigenic structure similar to those of a chlamydial agent of epizootic bovine abortion (EBA). Intravenous inoculation of the fecal chlamydia into a pregnant heifer caused abortion and lesions in the fetus indistinguishable from those of experimentally induced EBA. In serotests with species-specific complement fixation antigens, the intestinal agent was similar to the EBA agent.  相似文献   
72.
A panel of monoclonal antibodies to the growth hormone (GH) receptor/binding protein was used to demonstrate the existence and detail the expression of GH receptors in ductal and alveolar epithelial cells from rat and rabbit mammary glands by immunohistochemistry. Intense immunoreactivity was present in membrane, cytoplasm and some nuclei of epithelial cells during proliferation and lactation. Receptor expression decreased during weaning and was absent or weak in regressive mammary glands. Immunoreactivity was weak in ductal epithelial cells from virgin adult animals. Pronounced expression of GH receptor/binding protein was observed with two monoclonal antibodies and lesser reactivity was seen with others, paralleling their affinities for the receptor. The cytoplasmic presence of this putatively plasma membrane located GH receptor is accounted for by the existence of a soluble form on the GH receptor, namely the growth hormone binding protein derived from the membrane receptor by cleavage. Primary localization of the receptor in proliferating and lactating epithelial cells suggests that the rat and rabbit mammary gland is a GH target tissue. This finding is in contradiction to both classical GH action and the somatomedin hypothesis and challenges the widely held view that GH has no direct influence on mammary growth and function.  相似文献   
73.
Differentiation of fiber types in developing canine skeletal muscle was studied, using morphologic, morphometric, and histochemical techniques. Sample collections were made from 6 muscles from the pectoral and pelvic limbs of 16 healthy pups between 1 day and 12 weeks of age. In newborn pups, 90% to 95% of the fibers in the 6 muscles were classified as undifferentiated or type IIC; the remaining fibers were classified either normal or large-size type I. Large-size type I fibers usually accounted for 2% to 4% of the total population and were considered analogous with the B fiber of Wohlfart. These fibers were larger than all other fiber types and disappeared after pups reached 4 to 5 weeks of age. After 2 to 4 weeks, the number of undifferentiated fibers decreased with the appearance of, and the concomitant numerical increases of, normal size type I and type IIA fibers. The percentages of type I and IIA fibers approached proportions of the adult dog by 12 weeks, at which time a type IIA fiber predominance was present in biceps femoris, lateral head of the gastrocnemius, cranial tibial, and long head of the triceps. Type I fibers predominated in medial head of the triceps and superficial digital flexor after 4 to 5 weeks. The mean fiber diameters of type I and IIA fibers were similar to any given muscle throughout the postnatal development. All fiber types stained uniformly with the oxidative stain nicotinamide adeninedinucleotide-tetrazolium reductase during the first 12 weeks of life, whereas a distinction between type I and II fibers was evident after 3 to 4 weeks with the periodic acid-Schiff stain reaction.  相似文献   
74.
A portoazygous venous shunt was identified in the caudodorsal aspect of the thorax in a young basset hound. During thoracotomy, the anomalous vessel was encircled with sterile cellophane tape. The vein became occluded based on postoperative radiographic examination and improved clinical function five weeks after surgery.  相似文献   
75.
Carbon stabilization by macroaggregate-occluded microaggregates (Mm) has been proposed as a principal mechanism for long-term soil organic carbon (SOC) sequestration in temperate alternative agricultural and (af)forested systems. The aim of this study was to evaluate the importance of the Mm fraction for long-term C stabilization in Oxisols and to validate its diagnostic properties for total SOC changes upon changes in land use. Soil samples were taken from the 0-5 and 5-20 cm soil layers of native forest vegetation (NV), conventional tillage (CT) and no-tillage (NT) systems at an experimental site near Passo Fundo and one near Londrina in Southern Brazil. After aggregate-size separations by wet-sieving, macroaggregate-occluded water-stable microaggregates (53-250 μm) (Mm) were isolated from large (>2000 μm) and small (>250 μm) macroaggregates. Particulate organic matter located inside the Mm (intra-Mm-POM) and the mineral fraction (< 53 μm) associated with the Mm (mineral-Mm) were separated from the POM fraction located outside the Mm (inter-Mm-POM) by density flotation followed by mechanical dispersion. Sand-free Mm-C concentrations on a macroaggregate basis were generally greater under NV and NT compared to CT in the 0-5 cm depth at both sites. Our findings support the importance of Mm (especially the mineral-Mm fraction) as long-term C-stabilization sites in highly weathered tropical soils under sustainable agricultural and natural systems. At both sites, significant differences in total SOC stocks (g C m−2) among different land use systems were always accompanied by parallel Mm-C stock differences. Though total SOC did not differ among land use systems in the 0-20 cm depth at both sites, Mm-C stocks were greater under NT compared to the CT treatment in the 0-20 cm depth at the Londrina site. We concluded that in these highly weathered tropical soils the Mm-C fraction is a more responsive fraction to management changes than total SOC and represents a diagnostic fraction for present as well as potential total SOC changes upon land-use change.  相似文献   
76.
A paramyxovirus was isolated from cerebrospinal fluid of a dog with a history of incoordination and posterior paresis. The virus apparently was not related to canine distemper virus (CDV), considering the lack of virus neutralization with CDV-specific antibody, negative immunofluorescence with CDV-specific conjugate, and avirulence for ferrets. The virus was antigenically related to a prototype strain of canine parainfluenza virus, as determined by positive immunofluorescence with canine parainfluenza virus-specific conjugate and virus neutralization tests.  相似文献   
77.
  • 1. Recent approaches to the planning of marine protected area (MPA) networks for biodiversity conservation often stress the need for a representative coverage of habitat types while aiming to minimize impacts on resource users. As typified by planning for the Australian South‐east Marine Region, this strategy can be manipulated by political processes, with consequent biased siting of MPAs. Networks thus created frequently possess relatively low value for biodiversity conservation, despite significant costs in establishment and maintenance.
  • 2. Such biases can be minimized through application of the data‐driven and species‐based concept of key biodiversity areas (KBAs).
  • 3. By mapping locations of threatened species and populations that are highly aggregated in time or space, the KBA process allows marine sites of global biodiversity significance to be systematically identified as priority conservation targets. Here, the value of KBAs for marine conservation planning is outlined, and guidelines and provisional criteria for their application provided.
Copyright © 2008 John Wiley & Sons, Ltd.  相似文献   
78.
Genotype and environment sets of wheat cultivars and breeding lines were tested for bread making, dough mixing, dough rheology, protein composition and thiol/disulphide composition to find methods that could identify wheat with high baking quality (high-BQ) and moderate work input (moderate-WI) requirement using the mechanical dough development system. Wheat with these properties generally had a high baking response to ascorbic acid (AA) and a GluD1a (HMW-GS 2 + 12) allelic composition. Strong wheat with high WI and high-BQ generally had low baking response to AA and a GluD1d (HMW-GS 5 + 10) allelic composition. Using protein composition data to identify wheat of high-BQ (with AA) and moderate-WI, it was best to select wheat with as high as possible percent of SDS-unextractable polymeric protein (%UPP) in flour and as low as possible %UPP in total polymeric protein. Using a dough extension test for identifying wheat of high-BQ (with AA) and moderate-WI, it was best to select wheat with intermediate values for maximum resistance to extension (Rmax) and for values of extension at Rmax as high as possible within the intermediate Rmax range. Cysteine content of protein fractions and glutathione content of flour gave mostly poor to weak correlations with all baking and mixing properties.  相似文献   
79.
ESF is useful in treatment of open fractures and delayed union and nonunion fractures. The fixation pins can be placed away from the fracture site to avoid disruption of blood supply. The appliance is well tolerated and inexpensive, and many of the parts can be reused. Adjustment of the splint is possible to permit correction of stabilization for optimal results. Gradual reduction of frame rigidity improves the quality of healing by increasing the stress on the bone. As stiffness of the healing fracture increases, return of limb function occurs. Early fixator removal reduces patient morbidity and permits a return to normal activity.  相似文献   
80.
Wild species-related germplasm is widely used to introduce new alleles and/or increase heterozygosity in cultivated species. Twenty-four SSR markers, specifically designed for cultivated potatoes, were evaluated to determine the extent of genetic variation within and among ten accessions of Solanum chacoense (chc). Fifteen of these markers were informative: there was no polymorphism in one of the markers, four of the markers showed evidence that more than one locus was being amplified, and the other four markers failed to consistently amplify products. Heterozygosity in these 10 accessions ranged from 33% to 87%. Variation among accessions was the largest proportion of variance for three markers, variation among genotypes within accessions was the largest proportion for three markers, and for the other nine markers variation within genotypes (chromosome to chromosome) was the largest proportion. Genetic similarity averaged 29.5% across markers. Where accessions have already been screened and found to possess the trait of interest, multiple genotypes from those accessions should be evaluated to identify genotypes with the greatest expression of the trait.  相似文献   
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