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51.
Cadherin-mediated cell adhesion and signaling is essential for metazoan development and yet is absent from all other multicellular organisms. We found cadherin genes at numbers similar to those observed in complex metazoans in one of the closest single-celled relatives of metazoans, the choanoflagellate Monosiga brevicollis. Because the evolution of metazoans from a single-celled ancestor required novel cell adhesion and signaling mechanisms, the discovery of diverse cadherins in choanoflagellates suggests that cadherins may have contributed to metazoan origins. 相似文献
52.
Earthworms play an important role as primary decomposers in the incorporation and initial mixing of plant litter. This study explored the response of earthworms to increasing fertiliser inputs, pasture production and livestock numbers (and their influence on food availability and soil physical condition) on six different managements in sheep-grazed and fifteen different managements in dairy-grazed pastures in a variety of New Zealand soils.Native earthworms were only found in some low-fertility pastures. Accidentally introduced peregrine earthworms, when present, dominate pasture soils. Of these, endogeic earthworms dominated the earthworm community and were positively associated with soil types with higher bulk densities. Peregrine anecic earthworms were absent from most hill-country sheep-grazed pastures, however in more fertile and productive dairy-grazed pastures they reached a biomass of up to 2370 kg ha?1. Only anecic earthworms showed a positive response to the increasing pressures associated with higher potential dry matter inputs and liveweight loadings of grazing livestock on soil, while epigeic earthworms declined. The positive response of anecic earthworms probably reflects the combined effect of the increase in food resources, including dung and plant litter, available on the soil surface, and their lower susceptibility to livestock treading pressure. Anecic species may be a suitable substitute for incorporation of surface litter in those soils where livestock treading limits epigeic earthworm populations.This study confirmed previous observations of limited distribution of the introduced Aporrectodea longa in pastoral hill-country soils in the North Island, and their near absolute absence from the South Island of New Zealand. This would suggest that large areas of New Zealand pastoral farmed soils could benefit from the introduction of anecic species from other parts of New Zealand which already contain A. longa. 相似文献
53.
A 17-month-old cat presented for frequent swallowing, occasional cough and stertor. Radiographic evaluation revealed a soft tissue mass at the level of the soft palate. Oral examination revealed a soft tissue mass within the soft palate. Surgical resection was performed. Histopathology was consistent with a large developmental cyst. Following surgical management the cat has remained clinically free of signs for 2 months. 相似文献
54.
Gerdin JA Slater MR Makolinski KV Looney AL Appel LD Martin NM McDonough SP 《Journal of Feline Medicine and Surgery》2011,13(12):959-966
Anesthetic-associated death (AAD) in cats is infrequent, but occurs far more frequently than in people. Post-mortem investigations of AAD in cats are uncommon, and results only sporadically published. Here we report the findings in 54 cases of AAD in cats. Significant gross and/or microscopic pre-existing disease, including pulmonary, cardiac, and systemic disease, was detected in 33% of cases. Pulmonary disease was most frequently diagnosed (24% of cases), and included cases of Aelurostrongylus abstrusus infection (9% of cases). Heart disease, including two cases of hypertrophic cardiomyopathy, was less frequent (11% of cases). Four percent died from surgical complications. No?significant gross or microscopic disease was detected in 63% of cases. Additional studies are needed to determine if these findings are representative of AAD in cats in other geographic areas or with access to veterinary care. This study demonstrates that post-mortem investigation of AADs is an important and worthwhile endeavor. 相似文献
55.
ten Have R Wijngaard H Ariës-Kronenburg NA Straatsma G Schaap PJ 《Journal of agricultural and food chemistry》2003,51(8):2242-2245
The common mushroom Agaricus bisporus is a non-white rot saphrophytic fungus that can degrade lignin to free and utilize holocellulose embedded in fermented straw as present in compost. A new method is described to estimate the actual amount of bioavailable holocellulose in 3.8 kg compost cultures spawned with A. bisporus Horst U1 prior to and during a cultivation with two cycles of mushroom harvesting. The method shows that the initial amount of bioavailable holocellulose per culture, accounting for 130 +/- 22 g, is lower than the total holocellulose consumption by A. bisporus accounting for 182 +/- 15 g. This difference is explained by a 30% increase in bioavailable holocellulose. The increase is caused by the degradation of 95 +/- 3 g of holocellulose-shielding lignin. The results are discussed within the scope of the A. bisporus mushroom yield and lignin degradation by white rot fungi during growth on lignocellulose-containing materials. 相似文献
56.
57.
Johnson PJ Scotty NC Wiedmeyer C Messer NT Kreeger JM 《Journal of the American Veterinary Medical Association》2005,226(4):584-8, 542
An 18-year-old Spanish Mustang mare was referred for evaluation of progressive weight loss and persistent hyperglycemia. Clinicopathologic abnormalities included marked hyperglycemia and glycosuria. Serum cortisol concentration was appropriately decreased following administration of dexamethasone, indicating that the horse did not have pituitary pars intermedia dysfunction. Serum insulin and plasma C-peptide concentrations were low, suggesting that hyperglycemia was a result of decreased secretion of insulin by pancreatic beta cells. In addition, glucose concentration did not return to the baseline concentration until 5 hours after i.v. administration of a glucose bolus, suggesting that insulin secretion, insulin effect, or both were reduced. However, i.v. administration of insulin caused only a slight decrease in the plasma glucose concentration, giving the impression that the action of insulin was impaired. Within 5 hours after administration of a combination of glyburide and metformin, which is used to treat diabetes mellitus in humans, the glucose concentration was within reference limits. The horse was euthanized, and a postmortem examination was done. Immunohistochemical staining of sections of the pancreas revealed attenuation of the pancreatic islet beta-cell population, with beta cells that remained generally limited to the periphery of the islets. These findings indicate that, albeit rare, pancreatic beta-cell failure may contribute to the development of diabetes mellitus in horses. 相似文献
58.
ABSTRACT Multilocus haplotypes (MLHs) were derived for the spermogonial (monokaryotic haploid) stage of Cronartium ribicola, the causal agent of white pine blister rust. Six random amplified polymorphic DNA loci and three single-strand conformational polymorphism markers were analyzed for 246 rust samples collected from two heavily infected white pine plantations. All cankers sampled were spatially located within the plantations. The hypothesis that spores are not locally disseminated was supported by the absence of any spatial clustering in the distribution of the MLHs. A large number of MLHs was found at both sites and the haplotypic diversity was close to the maximum (one) in both populations. All measures of recombination were not different from expectations under a scenario of sexual recombination. Genetic differentiation between the two sites was very low (theta = 0.023), yet it was significantly different from zero (P < 0.01). This analysis is in agreement with a scenario of extensive sexual recombination followed by some long-distance dispersal. 相似文献
59.
60.
Iridium-192 interstitial brachytherapy as adjunctive treatment for canine cutaneous mast cell tumors
Northrup NC Roberts RE Harrell TW Allen KL Howerth EW Gieger TL 《Journal of the American Animal Hospital Association》2004,40(4):309-315
Eleven dogs with cutaneous mast cell tumors (MCTs) were treated with surgery and iridium-192 ((192)Ir) interstitial brachytherapy. Minimum tumor doses ranged from 47.2 to 63.3 Gy. Treated tumors were classified as grade II (n=7) or III (n=4). Five dogs had recurrences with a median progression-free interval of 1391 days, and six dogs had no recurrence at a median follow-up time of 942 days. Acute adverse effects were well tolerated, and late effects were mild. One dog developed a second tumor of a different cell type in the radiation treatment field. 相似文献