谁能给我翻译一下生物工程专业文献

Cell cycle engineeringThis direct approach has also been used to manipulate the cell cycle genes to increase or decrease proliferation rate and thereby to enhance productivity. When c-myc gene transfected into CHO cells a significant increase in proliferative rate of CHO cell line is demonstrated (Ifandi and Al-Rubeai 2005). Over-expression of both c-myc and bcl-2 resulted in a cell line with increased proliferation and maximum cell densities while a decrease in apoptosis was achieved (Ifandi and Al-Rubeai 2005). Another cell cycle associated gene, p21, has had its potential for inducing cytostasis exploited. Research has shown that by using an inducible p21CIP1 vector a 4 fold increase in antibody productivity resulted in a suspension NS0 culture (Watanabe et al. 2002). Further work showed that this engineered cell line had an increased cell volume, ribosomal protein S6, mitochondrial activity and mitochondrial mass when induced suggesting that p21CIP1induced cell cycle arrest uncouples cell growth from cell cycle progression (Bi et al. 2004). This in-turn was directly related with productivity. Early work with inducing cell arrest was done utilising the interferon regulatory factor 1 (IRF-1) to regulate cell growth (Kirchhoff et al. 1993; Koester et al. 1995) and increase production in BHK-21 cells via estradiol induction (Kirchhoff et al. 1996). However, this work demonstrated that when using the IRF-1 cytostatic gene the main task is keeping the viability high as this has a tendency to decrease with time. By controlling the addition and removal of estradiol, hence modulate IRF-1 activity, it is possible to overcome the loss in viability (Carvalhal et al. 2001). Other studies have also investigated the use of cytostatic genes on CHO cells secreting alkaline phosphatase (SEAP) with similar effects of higher productivity when cell are growth arrested (Carvalhal et al. 2003; Mazur et al. 1998). An example is the use of the p27KIP1 gene induced by acetylaldehyde gas which allowed increased SEAP production in HEK.EBNA cells (Werner et al. 2006). Apart from the control of cell cycle by the p27KIP1 gene, the use of acetylaldehyde as an inducing agent has several advantages in terms of low cost, precise fine tuning of transgene expression (Weber et al. 2004), the use of concentrations below observable toxicities (Hartenbach and Fussenegger 2005; Weber et al. 2005b), and ease of removal prior to downstream processing (Weber et al. 2005a).