Cytotechnology. 2004 Jan;44(1-2):67-76. doi: 10.1023/B:CYTO.0000043413.53044.fa.
The potential of spent medium to support the growth and recombinant protein production of High-Fivetrade mark cells was investigated. Growth in medium consisting of three parts fresh and one part spent medium was comparable to that in fresh medium (maximal specific growth rates of 0.028 and 0.029 h(-1), and maximal cell densities of 4 and 4.5 x 10(6) cells ml(-1), respectively). Glucose exhaustion coincided with an abrupt decrease of viability. Of 15 amino acids analyzed, not a single one was completely exhausted at the end of the growth phase. Growth in medium consisting of equal parts spent and fresh medium led to lower maximal cell concentration (2.9 x 10(6) cells ml(-1)) with a smoother death phase. Glucose supplementation at the beginning of the culture or at the end of the growth phase did not lead to an increase of either the maximal cell density or the specific growth rate. Infection of High-Fivetrade mark cells at three different densities (1.4, 2.5 and 4.2 x 10(6) cells ml(-1)) without medium change led to monotonically decreased specific productions for beta-galactosidase. Partial (75%) or total medium replacement at the higher infection density restored the specific production at the levels of the intermediate density infection (321, 292 and 389 U.(10(6) cells)(-1), respectively).
考察了用过的培养基在支持 High-Five 标记细胞的生长和重组蛋白生产方面的潜力。在由三份新鲜培养基和一份用过的培养基组成的培养基中生长与在新鲜培养基中的生长相当（最大比生长速率分别为 0.028 和 0.029 h(-1)，最大细胞密度分别为 4 和 4.5 x 10(6) 细胞/ml(-1)）。葡萄糖耗尽与细胞活力的急剧下降同时发生。在分析的 15 种氨基酸中，没有一种在生长阶段结束时完全耗尽。在由等量的用过的和新鲜的培养基组成的培养基中生长导致较低的最大细胞浓度（2.9 x 10(6) 细胞/ml(-1))，且死亡阶段更平缓。在培养开始时或生长阶段结束时补充葡萄糖既不会增加最大细胞密度，也不会增加比生长速率。在不更换培养基的情况下，以三种不同的密度（1.4、2.5 和 4.2 x 10(6) 细胞/ml(-1))感染 High-Five 标记细胞会导致β-半乳糖苷酶的比生产单调下降。在较高的感染密度下进行部分（75%）或完全（100%）培养基替换会将比生产恢复到中等密度感染的水平（分别为 321、292 和 389 U.(10(6) cells)(-1)）。
