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Samer AbuBakr Simone L. Macmil Mark A. Nanny Kathleen E. Duncan 《Soil biology & biochemistry》2008,40(8):2055-2062
Enzymatic transformation of humic acids (HA), fulvic acids (FA) and indole was examined using naphthalene 1,2-dioxygenase (NDO). NDO was used as a model for dioxygenase enzymes found in various microbial species. Indole was used as a model substrate for NDO-catalyzed reactions resulting in condensation products. Although NDO is not classified as a soil enzyme, all HA and FA tested were susceptible to NDO-induced transformation. The extent of NDO-specific NADH oxidation in solutions containing HA and FA paralleled the percent aromaticity of the HA and FA. Furthermore, the UV–Vis absorptive properties of NDO-treated HA and FA were altered in a manner suggesting condensation reactions similar to the formation of indigo from indole. Condensation reactions were enhanced in NDO-treated mixtures containing indole and an FA. NDO retained activity for 2 weeks under ambient conditions, and retained some enzymatic activity for 9 days based on detection of specific metabolites by HPLC, suggesting prolonged extracellular activity. Humic substances have not previously been known to be substrates for dioxygenases; even more significant was that dioxygenase enzymes can facilitate condensation reactions between indole-like functional groups well-known to be present in HA and FA. These results illustrate how dioxygenases can be potential humic-modifying enzymes when released into the environment upon microbial death and concurrent cell lysis which could alter the bioavailability of organic contaminants associated with dissolved organic matter through specific modulation of enzyme activity involving substrate competition. 相似文献
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Nanny Wenzlow Dan Neal Adam W. Stern Dhani Prakoso Junjie J. Liu Gretchen H. Delcambre Sally Beachboard Maureen T. Long 《Journal of veterinary diagnostic investigation》2021,33(5):825
Estimation of the postmortem interval (PMI) is a poorly studied field in veterinary pathology. The development of field-applicable methods is needed given that animal cruelty investigations are increasing continually. We evaluated various histologic criteria in equine brain, liver, and muscle tissue to aid the estimation of PMI in horses, which is central to forensic investigations of suspicious death. After death, autolysis proceeds predictably, depending on environmental conditions. Currently, no field-applied methods exist that accurately estimate the PMI using histology in animals or humans through quantification of autolysis. Brain, liver, and skeletal muscle from 12 freshly euthanized horses were held at 22°C and 8°C for 72 h. Tissues were sampled at T0h, T1h, T2h, T4h, T6h, T12h, T24h, T36h, T48h, T60h, and T72h. For each tissue, we quantified 5 to 7 criteria associated with autolysis, based on the percentage of microscopic field involved. Each criterion was modeled, with temperature and time as independent variables. Changes were most predictable in liver and muscle over the first 72 h postmortem. The criteria for autolysis that were present most extensively at both temperatures were hepatocyte individualization and the separation of bile duct epithelium from the basement membrane. The changes that were present next most extensively were disruption of myofiber continuity, hypereosinophilia, and loss of striation. Brain changes were highly variable. The high statistical correlation between the parameter “autolysis” and the variables “time/temperature”, indicates that autolysis is progressive and predictable. Further investigation of these criteria is needed to establish histologic algorithms for PMI. 相似文献
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Signaling lymphocyte activation molecule (SLAM) or CD150 can function as a receptor for the canine distemper virus (CDV) in vitro. The expression of SLAM was studied using immunohistochemistry in order to evaluate the presence and distribution of the receptor in dogs in vivo. Additionally, receptor expression was assessed after experimental infection of dogs with CDV. In 7 control dogs without distemper virus, the receptor was found in various tissues, mostly on cells morphologically identified as lymphocytes and macrophages. In 7 dogs with early distemper lesions characterized by presence of the virus, higher numbers of SLAM-expressing cells were found in multiple tissues recognized as targets of CDV compared with those in control dogs. These findings suggest that SLAM, a putative distemper receptor, is expressed in dogs in vivo. Additionally, virus infection is associated with up-regulation of SLAM, potentially causing an amplification of virus in the host. 相似文献
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N. Wenzlow M. S. Tivers L. E. Selmic E. J. Scurrell S. J. Baines K. C. Smith 《The Journal of small animal practice》2009,50(9):488-491
A 11-year-old, female, spayed greyhound was presented with a haemorrhagic discharge from the vulva. Clinical examination, vaginoscopy and a computed tomography scan showed an irregular egg-sized mass in the region of the cervix and uterine stump. An endoscopic grab biopsy (incisional) suggested a malignant mesenchymal tumour. Following this, surgical excision of the cranial vagina, cervix and the uterine remnant was performed. The final diagnosis of haemangiosarcoma was based on histological examination of the larger excisional biopsy specimen and was confirmed by positive immunolabelling of the neoplastic endothelial cells for the von Willebrand factor. 相似文献
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Examination of electrophoretic mobility patterns indicates that the strain designations of 44 classical strains of Tetrahymena are confused. It is suggested that new designations be made on the basis of phenotypic similarity. 相似文献
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