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Culture Temperature (culture + temperature)
Selected AbstractsRelevance of incubation temperature for Vibrio salmonicida vaccine productionJOURNAL OF APPLIED MICROBIOLOGY, Issue 6 2002D.J. Colquhoun Aims:,To investigate the relationships between water temperature, bacterial growth, virulence and antigen expression in Vibrio salmonicida, the causal agent of cold water vibriosis in Atlantic salmon (Salmo salar L.). Methods and Results:,The significance of sea temperature was investigated using historical clinical and oceanographic data. An upper threshold for disease of approx. 10°C was established. The effects of culture temperature and media type on bacterial growth were studied on solid and in liquid media. The highest rates of cell division were identified at 15°C on solid media and 10°C in liquid media. Outer membrane protein (OMP) expression and serological response in Atlantic salmon were studied using sodium dodecyl sulphate-polyacrylamide gel electrophoresis, Western blotting and enzyme-linked immunosorbent assay. A novel 76-kDa OMP produced in unshaken cultures at 10°C was not found to stimulate a specific humoral response. Conclusions:,Diagnostic agar plate-based incubation of suspected V. salmonicida should be carried out at 15°C. High yield broth cultures for vaccine production should be incubated at 10°C or lower. Significance and Impact of the Study:,This study is, to the best of our knowledge, the first to identify different optimal temperatures in a bacterial species cultured on physically different types of media. The evidence presented suggests that V. salmonicida and possibly other bacteria destined for vaccine use in poikilothermic organisms should be cultured at temperatures consistent with that at which disease occurs. [source] TEMPERATURE INDUCED PHOTOINHIBITION IN OUTDOOR CULTURES OF MONODUS SUBTERRANEUSJOURNAL OF PHYCOLOGY, Issue 2000A. Vonshak Outdoor algal cultures are continuously exposed to changes in environmental conditions, particularly irradiance and temperature. While the changes in light intensity take place in a range of one to two hours, the increase in temperature is a slower process and takes about four to five hours. This de-synchronization between the two important environmental factors governing photosynthesis and growth of algae results in a unique stress condition where photoinhibition can be induced at relatively low light intensity. Outdoors the early morning culture temperature was found to be about 12 to 14° C, and reaches 25 to 28° C at mid-day. In an experiment, such a natural temperature regime was compared to another one in which the morning temperature of the culture was increased to 20° C by using a heating system. A fast decline in the maximal photochemical efficiency of PSII (Fv/Fm) was observed starting as soon as sunrise. The decline was faster in the non-heated culture and was to a lower value. The diurnal changes in the electron transfer rate (ETR) and in the non-photochemical quenching (NPQ) of the cultures, indicated that the early morning exposure of cells to sub-optimal temperature results in a fast inactivation of PSII activity which was reflected in an inhibition of the photosynthetic activity even when the two cultures finally reached the same temperature at mid-day. Thus, under the same light and temperature mid-day conditions the ETR was higher and the NPQ was significantly lower in the heated culture. Significant changes in productivity of the cultures also were observed. [source] Candida glabrata, an emerging fungal pathogen, exhibits superior relative cell surface hydrophobicity and adhesion to denture acrylic surfaces compared with Candida albicansAPMIS, Issue 9 2002G. Luo Oral candidosis is a common opportunistic infection in debilitated individuals and Candida glabrata is the second most frequently isolated species from this condition, after Candida albicans. Candidal adherence to various biological or non-biological surfaces is considered a prerequisite for colonization, and pathogenesis of candidal infections, and their relative cell surface hydrophobicity (CSH) is likely to be a possible contributory force involved in this process. Whereas a large body of data on the latter features of C. albicans is available, there is surprisingly little information on C. glabrata. As a comprehensive database on the relative adhesion and CSH of Candida spp. is instructive and useful, we investigated in vitro the latter attributes of 34 oral isolates of C. glabrata and 15 isolates of C. albicans. There were remarkable intraspecies differences in both the CSH and the adhesive ability of C. glabrata strains (p<0.001). Compared with C. albicans, C. glabrata demonstrated a four-fold greater CSH value (30.63±11.20% vs 7.23±3.56%, p<0.0001) and a two-fold greater tendency to adhere to denture acrylic surfaces (75.18±39.96 vs 30.36±9.21, p<0.0001). A significant positive correlation between CSH and adhesion was also noted for both C. glabrata (r=0.674, p<0.0001) and C. albicans (r=0.636, p<0.05). When the effect of different incubation conditions on the relative CSH and adherence of C. glabrata was examined, CSH and the adherence to acrylic surfaces of four of six C. glabrata isolates were significantly affected by a reduction of the culture temperature (from 37 °C to 25 °C). A positive relationship also emerged when the temperature-induced variations in the adherence values were correlated with their relative CSH. These data provide hitherto unavailable archival information on important pathogenic attributes of the two most common oral Candida species that may help explain their predominance in this milieu. [source] Enhanced interferon-, production by CHO cells through elevated osmolality and reduced culture temperatureBIOTECHNOLOGY PROGRESS, Issue 5 2009Young Kue Han Abstract For efficient production of native interferon-, (IFN-,) in recombinant CHO cell culture, the IFN-, molecular aggregation that occurs during culture needs to be minimized. To do so, we investigated the effect of hyperosmolality and hypothermia on IFN-, production and molecular aggregation in rCHO cell culture. Both hyperosmolality (470 mOsm/kg) and hypothermia (32°C) increased specific native INF-, productivity qIFN-,. Furthermore, they decreased the IFN-, molecular aggregation, although severe IFN-, molecular aggregation could not be avoided in the later phase of culture. To overcome growth suppression at hyperosmolality and hypothermia, cells were cultivated in a biphasic mode. Cells were first cultivated at 310 mOsm/kg and 37°C for 2 days to rapidly obtain a reasonably high cell concentration. The temperature and osmolality were then shifted to 32°C and 470 mOsm/kg, respectively, to achieve high qIFN-, and reduced IFN-, molecular aggregation. Due to the enhanced qIFN-, and delayed molecular aggregation, the highest native IFN-, concentration achieved on day 6 was 18.03 ± 0.61 mg/L, which was 5.30,fold higher than that in a control batch culture (310 mOsm/kg and 37°C). Taken together, a combination of hyperosmolality and hypothermia in a biphasic culture is a useful strategy for improved native IFN-, production from rCHO cells. © 2009 American Institute of Chemical Engineers Biotechnol. Prog., 2009 [source] 293 cell cycle synchronisation adenovirus vector productionBIOTECHNOLOGY PROGRESS, Issue 1 2009Tiago B. Ferreira Abstract As the market requirements for adenovirus vectors (AdV) increase, the maximisation of the virus titer per culture volume per unit time is a key requirement. However, despite the fact that 293 cells can grow up to 8 × 106 cell/mL in simple batch mode operations, for optimal AdV infection a maximum cell density of 1 × 106 cell/mL at infection time has usually been utilized due to the so called "cell density effect". In addition, AdV titer appears to be dependent upon cell cycle phase at the time of infection. To evaluate the dependence of AdV production upon cell cycle phase, 293 cells were chemically synchronised at each phase of the cell cycle; a 2.6-fold increase on AdV cell specific titer was obtained when the percentage of cells at the S phase of the cell cycle was increased from 36 to 47%; a mathematical equation was used to relate AdV cell specific productivities with cell synchronisation at the S phase using this data. To avoid the use of chemical inhibitors, a temperature shift strategy was also used for synchronisation at the S phase. S phase synchronisation was obtained by decreasing the culture temperature to 31°C during 67 h and restoring it to 37°C during 72 h. By using this strategy we were able to synchronise 57% of the population in the S phase of the cell cycle obtaining an increase of 7.3-fold on AdV cell specific titer after infection. © 2009 American Institute of Chemical Engineers Biotechnol. Prog., 2009 [source] Effect of Simultaneous Application of Stressful Culture Conditions on Specific Productivity and Heterogeneity of Erythropoietin in Chinese Hamster Ovary CellsBIOTECHNOLOGY PROGRESS, Issue 4 2004Sung Kwan Yoon A single stressful culture condition induced by hypoosmotic stress (210 mOsm kg,1), low culture temperature (32 °C), or NaBu addition (1 mM) resulted in a 1.8- to 2.2-fold enhancement of specific erythropoietin (EPO) productivity (qEPO) of recombinant Chinese hamster ovary (rCHO) cells compared to normal culture condition (37 °C and 310 mOsm kg,1). Simultaneous application of these stressful conditions further enhanced qEPO up to approximately 5-fold. However, the quality of EPO was affected by stressful culture conditions. The proportion of acidic isoforms of EPO under a single stressful condition was 2.8,13.8% lower than that under normal culture condition. Simultaneous application of the stressful conditions further decreased the portion of acidic isoforms but not significantly. Despite 5-fold enhancement of qEPO, the portion of acidic isoforms under the simultaneous application of stressful culture conditions was 12.9,21.6% lower than that under normal culture condition. Taken together, these results suggest the potential of simultaneous application of different stressful culture conditions to the production phase of two-stage culture, where cell growth and production phases are separated, for improved EPO production. [source] An Approach for Enhancing Heterologous Production of Providencia Rettgeri Penicillin Acylase in Escherichia coliBIOTECHNOLOGY PROGRESS, Issue 3 2000C. Perry Chou Heterologous production of Providencia rettgeri penicillin acylase (PAC) was optimized inEscherichia coli. Several factors, including carbon, temperature, and host effects, were identified to be critical for the enzyme overproduction. The optimum culture conditions for the enzyme production vary for different host/vector systems. With the optimization, both volumetric and specific PAC activities could be significantly improved by more than 50-fold compared to the native expression in P. rettgeri. The heterologous production could be possibly limited by translation or posttranslational steps, depending on the culture temperature and host/vector system. To our knowledge, this is the first evidence demonstrating the limiting step for the production of P. rettgeri PAC and the existence of the P. rettgeri PAC precursor. 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