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Morphological and Immunohistochemical Characterization of Canine Osteosarcoma Spheroid Cell Cultures 下载免费PDF全文
Spheroid cell culture emerges as powerful in vitro tool for experimental tumour research. In this study, we established a scaffold‐free three‐dimensional spheroid system built from canine osteosarcoma (OS) cells (D17). Spheroids (7, 14 and 19 days of cultivation) and monolayer cultures (2 and 7 days of cultivation) were evaluated and compared on light and electron microscopy. Monolayer and spheroid cultures were tested for vimentin, cytokeratin, alkaline phosphatase, osteocalcin and collagen I by means of immunohistochemistry. The spheroid cell culture exhibited a distinct network of collagen I in particular after 19‐day cultivation, whereas in monolayer cultures, collagen I was arranged as a lamellar basal structure. Necrotic centres of large spheroids, as observed in 14‐ and 19‐day cultures, were characterized by significant amounts of osteocalcin. Proliferative activity as determined by Ki‐67 immunoreactivity showed an even distribution in two‐dimensional cultures. In spheroids, proliferation was predominating in the peripheral areas. Metastasis‐associated markers ezrin and S100A4 were shown to be continuously expressed in monolayer and spheroid cultures. We conclude that the scaffold‐free spheroid system from canine OS cells has the ability to mimic the architecture of the in vivo tumour, in particular cell–cell and cell–matrix interactions. 相似文献
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Wittig W Hoffmann K Müller H Johne R 《Berliner und Münchener tier?rztliche Wochenschrift》2007,120(3-4):113-119
Between 2000 and 2004 a disease occurred in an aviary in Germany affecting various bird species belonging to the order Passeriformes including Collared Grosbeaks (Mycerobas affinis), Eurasian Bullfinches (Pyrrhula pyrrhula griseiventris), Brown Bullfinches (Pyrrhula nipalensis), Grey-headed bullfinches (Pyrrhula erythaca) and Yellow-bellied Tits (Periparus venustulus).The major clinical signs included increased mortality of fledglings and young birds, as well as feather disorders and feather loss in adult birds. In addition, adult Eurasian Bullfinches showed in one year a disease course, in which the major symptom was inflammation of the skin beginning on the basis of the beak and spreading over the head occurring a few days before death. Bacteriological and parasitological investigations did not reveal any consistent findings. Using a newly developed polymerase chain reaction protocol, DNA of the recently discovered finch polyomavirus (FPyV) was demonstrated in several affected birds. Because of the consistent detection of FPyV-DNA and the similarity of the symptoms with those observed during infection with the closely related avian polyomavirus in other bird species, an etiological role of FPyV in the observed disease is assumed. 相似文献
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Walter H. Gardner 《Irrigation Science》1988,9(4):255-264
Summary Surrounded by many sophisticated instruments, data acquisition systems and connecting computers, contemporary soil and plant scientists may not fully appreciate what really was known in earlier times and how the science has developed. A short review and a few examples of the growth of measurements and ideas are presented here. 相似文献
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Godelieve Gheysen Walter Van der Eycken Nathalie Barthels Mansour Karimi Marc Van Montagu 《Pest management science》1996,47(1):95-101
The molecular interactions between plants and sedentary nematodes are undergoing intense study, not only for reasons of fundamental research but also for the potential benefits to agriculture. The present technology allows the transformation of an increasing number of crop plants, providing new ways to introduce resistance against plant-parasitic nematodes. The ability of sedentary nematodes to induce specialized feeding sites in plant roots is one of the most fascinating aspects of this host–parasite interaction. Molecular approaches have been initiated to identify and characterize plant genes altered in expression after infection by sedentary nematodes. The results obtained indicate that many genes indeed become up-regulated upon nematode infection. Surprisingly, several so-called constitutive promoters that are normally used to achieve high expression in plant cells are completely ‘silenced’ in the feeding sites within days after nematode infection. Generally, there are two options available for the genetic engineering of nematode resistance: the synthesis of anti-nematode proteins or the localized production of a cytotoxic protein that interferes with the development of feeding cells. Nematode-induced promoters are very useful for the production by plants of sufficiently high levels of anti-nematode proteins at feeding sites. Alternatively, interfering with feeding-cell development is somewhat similar to the hypersensitive response evoked by nematodes in a naturally resistant plant. Here, destruction of specific plant cells can be achieved by the localized expression of a cytotoxin such as barnase, a potent ribonuclease. This approach, however, calls for a highly specific ‘non-leaky’ promoter, which is active only in the feeding cells. Another possibility is to use a two-component system, where the leakiness of the promoter in other tissues is counterbalanced by the constitutive expression of a neutralizing gene. 相似文献
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Valentina Gonzlez María Jos Vargas-Straube Walter O. Beys-da-Silva Luclia Santi Pedro Valencia Fabrizio Beltrametti Beatriz Cmara 《Marine drugs》2020,18(11)
Marine actinobacteria are viewed as a promising source of enzymes with potential technological applications. They contribute to the turnover of complex biopolymers, such as pectin, lignocellulose, chitin, and keratin, being able to secrete a wide variety of extracellular enzymes. Among these, keratinases are a valuable alternative for recycling keratin-rich waste, which is generated in large quantities by the poultry industry. In this work, we explored the biocatalytic potential of 75 marine-derived actinobacterial strains, focusing mainly on the search for keratinases. A major part of the strains secreted industrially important enzymes, such as proteases, lipases, cellulases, amylases, and keratinases. Among these, we identified two streptomycete strains that presented great potential for recycling keratin wastes—Streptomyces sp. CHA1 and Streptomyces sp. G11C. Substrate concentration, incubation temperature, and, to a lesser extent, inoculum size were found to be important parameters that influenced the production of keratinolytic enzymes in both strains. In addition, proteomic analysis of culture broths from Streptomyces sp. G11C on turkey feathers showed a high abundance and diversity of peptidases, belonging mainly to the serine and metallo-superfamilies. Two proteases from families S08 and M06 were highly expressed. These results contributed to elucidate the mechanism of keratin degradation mediated by streptomycetes. 相似文献