Petersen J F, McIntire L V, Papoutsakis E T
Department of Chemical Engineering, Rice University, Houston, Texas 77251-1892.
Biotechnol Prog. 1990 Mar-Apr;6(2):114-20. doi: 10.1021/bp00002a004.
Previously, we observed that CRL-8018 hybridoma cells were more sensitive to well-defined viscometric shear during the lag and stationary phases than during the exponential phase of batch cultures. Some potential hypotheses for explaining the increase in shear sensitivity are (1) nutrient limitations that result in a decrease in production of specific cellular components responsible for the mechanical strength of the cell, (2) nutrient limitations that lead to synchronization of the culture in a cell cycle phase that is more sensitive to shear, or (3) a link between cell growth and shear sensitivity, such that slowly growing cells are more sensitive to shear. Here, the duration of the exponential phase was increased with use of fed-batch, and the effect on shear sensitivity of the cultures was measured with a viscometric technique. Extension of exponential growth resulted in an increased period during which the cells were insensitive to shear. Additionally, the shear sensitivity of the cells was constant over a wide range of growth rates and metabolic yields in chemostat cultures. These observations suggest that as long as the cells are actively (exponentially) growing, their shear sensitivity does not depend on the growth rate or metabolic state of the cell as expressed by metabolic yields. Thus, hypothesis 3 above can be dismissed.
此前，我们观察到CRL - 8018杂交瘤细胞在分批培养的延迟期和稳定期比指数期对明确的粘度剪切更敏感。一些解释剪切敏感性增加的潜在假设是：（1）营养限制导致负责细胞机械强度的特定细胞成分产量下降；（2）营养限制导致培养物在对剪切更敏感的细胞周期阶段同步化；或（3）细胞生长与剪切敏感性之间存在联系，使得生长缓慢的细胞对剪切更敏感。在此，使用补料分批培养延长了指数期的持续时间，并使用粘度技术测量了培养物对剪切敏感性的影响。指数生长的延长导致细胞对剪切不敏感的时间增加。此外，在恒化器培养中，细胞的剪切敏感性在很宽的生长速率和代谢产率范围内保持恒定。这些观察结果表明，只要细胞在积极（指数）生长，其剪切敏感性不取决于细胞的生长速率或由代谢产率表示的代谢状态。因此，可以排除上述假设3。
