Effect of ORF238-expression on cell growth. MDS42-T7 cells harboring derivatives of the original ctxvp60 sequence inserted into the pSG1144 vector were grown in LB at 37°C. Overnight liquid cultures from colonies of freshly transformed cells were diluted into fresh medium and divided into two flasks. One of each pairs was induced by adding 1 mM of IPTG after 90 minutes growth (A+, B+, C+, D+ cultures, solid arrow), with the exception of E+, to which IPTG was added at 120 minutes (arrow with dashed line). (A, A+) pSG1144 vector (B, B+) pSG1144-ctxvp60 (C, C+) pSG1144-ctxvp60opt (D, D+) pSG1144-ctxvp60dezopt (E, E+) pSG1144-orf238.