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William R. Tolbert Joseph Peder Richard C. Kimes 《In vitro cellular & developmental biology. Plant》1981,17(10):885-890
Summary A system has been developed for growth and maintenance of mammalian cells in suspension culture at high density. In principle,
the maintenance of constant levels of required nutrients coupled with the removal of toxic cell byproducts can support much
higher suspension cell densities than may be obtained in conventional spinners. The system consisted of 4- or 40-liter reaction
vessels equipped with a vertically supported rotating cylindrical filter. Agitation was provided by the magnetically driven,
rotating filter. Fresh medium was supplied at a rate of 10 to 20 ml/h per 109 cells and the expended medium free of cells was withdrawn through the rotating filter. Both pH and dissolved O2 and CO2 were monitored and regulated. Walker 256 carcinosarcoma cells have been grown in these reactors to densities 10-to 30-fold
greater than that obtained in Bellco spinners. In addition to high cell densities, the yield of cells per liter of medium
used was 2- to 3-fold that obtained in the conventional systems. Both 4-and 40-liter versions of this reactor have been operated
without the use of antibiotics. The 40-liter reactor also has been modified for chemostat operation. In a single run, for
example, the Walker cell density was maintained between 6 and 10×106 cells/ml with a total yield of 8.7×1011 cells from 360 liters of medium. 相似文献
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Two clonal cell lines have been derived from the thoracic aorta of embryonic rats. Both of these cell lines, at some stage of their development possess membranes capable of generating overshooting action potentials spontaneously. Contiguous cells of each of these lines are electrically coupled. Ultrastructural analysis consistently reveals the presence of rows of pinocytotic vesicles, a well-developed rough endoplasmic reticulum, massive tracts of thin filaments oriented parallel to the longitudinal axis of the cell and randomly dispersed intermediate sized filaments. The specific activities of the enzymes myokinase and creatine phosphokinase (CPK) increase 3- to 5-fold after growth has ceased. These two cell lines synthesize a muscle type CPK isoenzyme after the cessation of cell division. It is concluded that these cell lines proliferate as myoblasts and develop into cells which phenotypically resemble smooth muscle. A third clonal cell line, from fetal rat aorta, with properties of both smooth and skeletal muscle, is also described. 相似文献
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Joel Ralston Lydia Lorenc Melissa Montes William V. DeLuca Jeremy J. Kirchman Bradley K. Woodworth Stuart A. Mackenzie Amy Newman Hilary A. Cooke Nikole E. Freeman Alex O. Sutton Lila Tauzer D. Ryan Norris 《Ecology and evolution》2019,9(15):8840-8855
Migratory behaviors such as the timing and duration of migration are genetically inherited and can be under strong natural selection, yet we still know very little about the specific genes or molecular pathways that control these behaviors. Studies in candidate genes Clock and Adcyap1 have revealed that both of these loci can be significantly correlated with migratory behaviors in birds, though observed relationships appear to vary across species. We investigated geographic genetic structure of Clock and Adcyap1 in four populations of blackpoll warblers (Setophaga striata), a Neotropical–Nearctic migrant that exhibits geographic variation in migratory timing and duration across its boreal breeding distribution. Further, we used data on migratory timing and duration, obtained from light‐level geolocator trackers to investigate candidate genotype–phenotype relationships at the individual level. While we found no geographic structure in either candidate gene, we did find evidence that candidate gene lengths are correlated with five of the six migratory traits. Maximum Clock allele length was significantly and negatively associated with spring arrival date. Minimum Adcyap1 allele length was significantly and negatively associated with spring departure date and positively associated with fall arrival date at the wintering grounds. Additionally, we found a significant interaction between Clock and Adcyap1 allele lengths on both spring and fall migratory duration. Adcyap1 heterozygotes also had significantly shorter migration duration in both spring and fall compared to homozygotes. Our results support the growing body of evidence that Clock and Adcyap1 allele lengths are correlated with migratory behaviors in birds. 相似文献
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Juliane I. Beier Jenny D. Jokinen Gretchen E. Holz Patrick S. Whang Amah M. Martin Nikole L. Warner Gavin E. Arteel Igor S. Lukashevich 《PloS one》2015,10(3)
Viral hemorrhagic fevers (VHFs) encompass a group of diseases with cardinal symptoms of fever, hemorrhage, and shock. The liver is a critical mediator of VHF disease pathogenesis and high levels of ALT/AST transaminases in plasma correlate with poor prognosis. In fact, Lassa Fever (LF), the most prevalent VHF in Africa, was initially clinically described as hepatitis. Previous studies in non-human primate (NHP) models also correlated LF pathogenesis with a robust proliferative response in the liver. The purpose of the current study was to gain insight into the mechanism of liver injury and to determine the potential role of proliferation in LF pathogenesis. C57Bl/6J mice were infected with either the pathogenic (for NHPs) strain of lymphocytic choriomeningitis virus (LCMV, the prototypic arenavirus), LCMV-WE, or with the non-pathogenic strain, LCMV-ARM. As expected, LCMV-WE, but not ARM, caused a hepatitis-like infection. LCMV-WE also induced a robust increase in the number of actively cycling hepatocytes. Despite this increase in proliferation, there was no significant difference in liver size between LCMV-WE and LCMV-ARM, suggesting that cell cycle was incomplete. Indeed, cells appeared arrested in the G1 phase and LCMV-WE infection increased the number of hepatocytes that were simultaneously stained for proliferation and apoptosis. LCMV-WE infection also induced expression of a non-conventional virus receptor, AXL-1, from the TAM (TYRO3/AXL/MERTK) family of receptor tyrosine kinases and this expression correlated with proliferation. Taken together, these results shed new light on the mechanism of liver involvement in VHF pathogenesis. Specifically, it is hypothesized that the induction of hepatocyte proliferation contributes to expansion of the infection to parenchymal cells. Elevated levels of plasma transaminases are likely explained, at least in part, by abortive cell cycle arrest induced by the infection. These results may lead to the development of new therapies to prevent VHF progression. 相似文献
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Buckmelter AJ Ren L Laird ER Rast B Miknis G Wenglowsky S Schlachter S Welch M Tarlton E Grina J Lyssikatos J Brandhuber BJ Morales T Randolph N Vigers G Martinson M Callejo M 《Bioorganic & medicinal chemistry letters》2011,21(4):1248-1252
Virtual and high-throughput screening identified imidazo[1,2-a]pyrazines as inhibitors of B-Raf. We describe the rationale, SAR, and evolution of the initial hits to a series of furo[2,3-c]pyridine indanone oximes as highly potent and selective inhibitors of B-Raf. 相似文献
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The scapula responds to the compressive states of its surrounding matrix produced by muscle functioning and weight bearing in the upper extremity with discernible structural correlates. These structural correlates can be utilized to infer locomotor behavior. After dissection and drying, the weights of several muscles of the shoulder region of 11 adult female baboons (Papio cynocephalus) were statistically compared to various dimensions of the bony scapula. A significant correlation was obtained between the weights of the individual compressive muscles, the combined weights of the compressive muscles and a scapular dimension of width. A nonsignificant correlation between these muscles and a sscapular dimension of length was also found. The results of this study were compared to those of a previous study of the scapular musculature in Macaca and opposing conclusions were obtained. The advisability of lumping macaques and baboons into a single gross locomotor category is rejected. 相似文献
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Plasminogen activator and MIF-like activities in Kirsten virus transformed mouse NIH culture fluids.
J Feder R C Kimes W R Tolbert C Cleveland M E Hammond N S Orenstein J Goodwin H F Dvorak 《Biochemical and biophysical research communications》1978,83(3):1164-1170
Kirsten virus transformed mouse NIH cells produce both a macrophage migration inhibition activity for guinea pig and mouse peritoneal exudate cells and a plasminogen activator. The migration inhibition factor activity exhibited thermal stability up to 80°C while the plasminogen activator was inactivated after 15 minutes at 70°C. Separation of these activities was achieved by absorption of the migration inhibition activity on agarose-fucosamine or high speed centrifugation. 相似文献