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Influence of hyperosmolar basal media on hybridoma cell growth and antibody production
No full textTo investigate the influence of hyperosmolar basal media on hybridoma response, S3H5/gamma 2bA2 and DB9G8 hybridomas were cultivated in a batch mode using hyperosmolar basal media resulting from additional sodium chloride supplementation. The basal media used in this study were IMDM, DMEM, and RPMI 1640, all of which are widely used for hybridoma cell culture. In IMDM, two hybridomas showed different responses to hyperosmotic stress regarding specific MAb productivity (q(MAb)), though they showed similar depression of cell growth in hyperosmolar media. Unlike S3H5/gamma 2bA2 hybridoma, the q(MAb) Of DB9G8 hybridoma was not enhanced significantly around 390 mOsm kg(-1). The variation of basal media influenced DB9G8 hybridoma response to hyperosmotic stress regarding q(MAb) In IMDM, the q(MAb) Of DB9G8 hybridoma was increased by more than 200% when the osmolality increased from 281 to 440 mOsm/kg. However, in RPMI 1640 and DMEM, similar amplitude of osmolality increase resulted in less than 100% increase in q(MAb) The variation of basal media also influenced the cell growth in hyperosmolar medium. Both hybridomas were more tolerant against hyperosmotic stress in DMEM than in IMDM, which was found to be due to the high osmolality of standard DMEM. The osmolalities of standard IMDM and DMEM used for inocula preparation were 281 and 316 mOsm kg(-1), respectively. Thus, when the cells were cultivated at 440 mOsm kg(-1), the cells in IMDM experienced higher osmotic shock than in DMEM. By using the inoculum prepared at 317 mOsm kg(-1) in IMDM, S3H5/gamma 2bA2 cell growth at 440 mOsm kg(-1) in IMDM was comparable to that in DMEM. Taken together, the results obtained from this study show that the selection of basal media is an important factor for MAb production by employing hyperosmotic stress
Application of Hypoosmolar Medium to Improve the Culture Longevity in Fed-Batch Culture of Hybridoma Cells
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Application of Hyperosmolar Medium to Improve Antibody Production of Immobilized Hybridoma Cells
No full textOsmoprotective effect of glycine betaine on foreign protein production in hyperosmotic recombinant Chinese hamster ovary cell cultures differs among cell lines
No full textWhen three recombinant Chinese hamster ovary (rCHO) cell lines, CHO/dhfr-B22-4, CS13-1.00*, and CS13-0.02*, were cultivated in hyperosmolar media resulting from NaCl addition, their specific foreign protein productivity increased with medium osmolality. However, due to a simultaneous suppression of cell growth at elevated osmolality, no enhancement in the maximum foreign protein titer was made in batch cultures. To test the feasibility of using glycine betaine, known as a strong osmoprotective compound, for improved foreign protein production in hyperosmotic rCHO cell cultures, hyperosmotic batch cultures were carried out in the presence of 15 mM glycine betaine. Glycine betaine was found to have a strong osmoprotective effect on all three rCHO cell lines. Inclusion of 15 mM glycine betaine in hyperosmolar medium enabled rCHO cell lines to grow at 557 to 573 mOsm/kg, whereas they could not grow in the absence of glycine betaine. However, effect of glycine betaine inclusion in hyperosmolar medium on foreign protein production differed among rCHO cell lines. CHO/dhfr-B22-4 cells retained enhanced specific human thrombopoietin (hTPO) productivity in the presence of glycine betaine, and thereby the maximum hTPO titer obtained at 573 mOsm/kg was increased by 72% over that obtained in the control culture with physiological osmolality (292 mOsm/kg). On the other hand, enhanced specific antibody productivity of CS13-1.00* and CS13-0.02* at elevated osmolality was decreased significantly in the presence of glycine betaine. As a result, the maximum antibody titer at 557 mOsm/kg was similar to that obtained in the control culture with physiological osmolality. The mRNA contents per cell determined by northern blot hybridization correlated with q in all three rCHO cell lines, indicating that transcriptional regulation is responsible in part for q enhancement at hyperosmolality in the absence as well as the presence of glycine betaine. Taken together, efficacy of the simultaneous use of hyperosmotic pressure and glycine betaine as a means to improve foreign protein production was variable among different rCHO cell lines. (C) 2000 John Wiley & Sons, Inc
Direct observation of the 2 (3)Pi(u) state of Rb-2 in a pulsed molecular beam: Rotational branch intensity anomalies in the 2 (3)Pi(u)(1(u))-X (1)Sigma(+)(g)(0(g)(+)) bands
No full textResonance enhanced two photon ionization study in a pulsed molecular beam identified spin-forbidden transitions of the 2 (3)Pi(u)(1(u))-X (1)Sigma(g)(+)(0(g)(+)) and 2 (3)Pi(u)(0(u)(+))-X (1)Sigma(g)(+)(0(g)(+)) of Rb-2. Lambda-doubling and interference-induced rotational branch intensity anomalies are observed for 2 (3)Pi(u)(1(u))-X (1)Sigma(g)(+)(0(g)(+)) transitions. The rotational constant for the 2 (3)Pi(u) state was determined to be B-e=0.018 932 5 +/- 0.000 007 4 cm(-1) for Rb-85(2), giving R-e=4.5796 +/- 0.0009 Angstrom. Other molecular parameters for Rb-85(2) are determined as T-e=19 784.254 +/- 0.009 cm(-1), omega(e)=42.200 +/- 0.006 cm(-1), omega(e)x(e)=0.171 +/- 0.001 cm(-1), and omega(e)y(e)=-0.001 06 +/- 0.000 06 cm(-1) for the 2 (3)Pi(u)(0(u)(+)) state and T-e=19 785.74 +/- 0.01 cm(-1), omega(e)=42.297 +/- 0.005 cm(-1), omega(e)x(e)=0.1725 +/- 0.0009 cm(-1), and omega(e)y(e)=-0.000 78 +/- 0.000 04 cm(-1) for 2 (3)Pi(u)(1(u)) state. These R-e, omega(e), and T-e values agree well with ab initio calculated values. The spin-orbit coupling constant A and Lambda-doubling parameters p and q are determined by simultaneous fitting of the rotational structures of both 2 (3)Pi(u)(1(u))-X (1)Sigma(g)(+) and 2 (3)Pi(u)(0(u)(+))-X (1)Sigma(g)(+) transitions. (C) 2000 American Institute of Physics. [S0021-9606(00)01830-4]
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
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