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101.
Yazgan Idris Turner Elizabeth G. Cronmiller Lauren E. Tepe Muammer Ozturk Taylan K. Elibol Murat 《Bioprocess and biosystems engineering》2018,41(3):423-434
Bioprocess and Biosystems Engineering - Maltose syrups have got wide-range utilizations in a variety of applications from bakery to drug-development. α-Amylases are among the most widely... 相似文献
102.
The paper reviews the published materials on phylogeny and philogeography of the salmonid fishes belonging to the genus Salvelinus within the framework of allopatric evolution. The present paper provides concise data on the origins of the main groups, the ways of their historical expansion and discusses the formation of the present ranges, taking into account the reconstruction of paleoclimate factors. Issues on the phylogenetic relations between the main groups, dating the major phylogenetic events, as well as the phylogenetic tree topology matchings are discussed here. 相似文献
103.
To date a considerable amount of data on sympatric diversification of the laсustrine fish has been accumulated and many important advances made. However, the evolutionary mechanisms of the process still remain unclear. The paper discusses fish polymorphism in the water bodies of different latitudes, but the major focus is the question of sympatry in the charrs of the genus Salvelinus across the northern lakes. Numerous cases of diversification were comparatively analyzed, which provides evidence for the existence of several main pathways of evolutionary process. The pathways are controlled by environmental factors, which determine the structure of the lake ecosystems in the northern latitudes. 相似文献
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Evaluation and applications of optical cell density probes in mammalian cell bioreactors 总被引:2,自引:0,他引:2
Wu P Ozturk SS Blackie JD Thrift JC Figueroa C Naveh D 《Biotechnology and bioengineering》1995,45(6):495-502
On-line optical cell density probes were implemented to continuously monitor the cell densities in mammalian cell bioreactor and to achieve advanced bioreactor controls. We tested cell density probes from six manufacturers in high cell density bioreactors. When externally calibrated, Aquasant and Ingold backscattering probes produced the most linear probe responses (PR) versus cell density (CD), followed by the ASR and Cerex laser probes. Monitek and Wedgewood transmission probes had lower resolutions. All probes were tested in two murine hybridoma fermentations. Cell densities varied between 1 x 10(6) cells/mL to 20 x 10(6) cells/mL and the bioreactors were operated for 5 to 7 weeks. For our bioreactors, Aquasant, Ingold, ASR, Wedgewood, and Monitek probes gave satisfactory responses. Little fouling was observed with any probe at the end of 2 weeks. Fouling was a possibility after 3 weeks in one bioreactor but its effect can be easily corrected. Cell density control and specific perfusion control of bioreactors based on the Aquasant probe were achieved. Implementation of cell density probe based perfusion control, instead of "step perfusion adjustments" based on manual hemacytometer control, will result in smoother operation, healthier cultures, increased medium delivery efficiency, and reduced operational excursions. (c) 1995 John Wiley & Sons, Inc. 相似文献
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Biosurfactants are amphiphilic compounds produced by several microorganisms that reduce the surface tension. Low toxicity, optimal activity in extreme conditions, biodegradability and production from several wastes are main advantages of biosurfactants as compared to synthetic surfactants. Production of biosurfactant by a white rot fungus Pleurotus djamor on sunflower seed shell in solid-state fermentation was determined by emulsification indexes, oil spreading activity and surface tension (28.82 ± 0.3mN/m) measurement. The critical micelle concentration was detected as 0.964 ± 0.09 mg/mL. Also, the chemical and physicochemical properties of the biosurfactant produced were investigated. Considering the results of the chemical contents analysis, HPLC, FT-IR and 1H-NMR, it can be concluded that the produced biosurfactant has a complex structure. Besides, resistance of its activity to environmental factors such as temperature, pH and salt concentration, as well as its thermal stability, were investigated. Additionally, the produced biosurfactant formed stabile emulsions with different hydrocarbons. Lastly, the performance of removing waste frying oil from contaminated sand of produced biosurfactant was detected as 76.57 ± 6%. Owing to its high emulsification capacity, low surface tension and critical micelle concentration, the biosurfactant, shows great potential for use in hydrocarbon removal applications. 相似文献
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L Diller J Kassel C E Nelson M A Gryka G Litwak M Gebhardt B Bressac M Ozturk S J Baker B Vogelstein et al. 《Molecular and cellular biology》1990,10(11):5772-5781
Mutations in the p53 gene have been associated with a wide range of human tumors, including osteosarcomas. Although it has been shown that wild-type p53 can block the ability of E1a and ras to cotransform primary rodent cells, it is poorly understood why inactivation of the p53 gene is important for tumor formation. We show that overexpression of the gene encoding wild-type p53 blocks the growth of osteosarcoma cells. The growth arrest was determined to be due to an inability of the transfected cells to progress into S phase. This suggests that the role of the p53 gene as an antioncogene may be in controlling the cell cycle in a fashion analogous to the check-point control genes in Saccharomyces cerevisiae. 相似文献