Few Single Nucleotide Variations in Exomes of Human Cord Blood Induced Pluripotent Stem Cells

The effect of the cellular reprogramming process per se on mutation load remains unclear. To address this issue, we performed whole exome sequencing analysis of induced pluripotent stem cells (iPSCs) reprogrammed from human cord blood (CB) CD34⁺ cells. Cells from a single donor and improved lentiviral vectors for high-efficiency (2–14%) reprogramming were used to examine the effects of three different combinations of reprogramming factors: OCT4 and SOX2 (OS), OS and ZSCAN4 (OSZ), OS and MYC and KLF4 (OSMK). Five clones from each group were subject to whole exome sequencing analysis. We identified 14, 11, and 9 single nucleotide variations (SNVs), in exomes, including untranslated regions (UTR), in the five clones of OSMK, OS, and OSZ iPSC lines. Only 8, 7, and 4 of these, respectively, were protein-coding mutations. An average of 1.3 coding mutations per CB iPSC line is remarkably lower than previous studies using fibroblasts and low-efficiency reprogramming approaches. These data demonstrate that point nucleotide mutations during cord blood reprogramming are negligible and that the inclusion of genome stabilizers like ZSCAN4 during reprogramming may further decrease reprogramming-associated mutations. Our findings provide evidence that CB is a superior source of cells for iPSC banking.     

Fermentation pattern ofZymomonas mobilis strains on different substrates—a comparative study

The optimum conditions (pH and initial sugar concentration) of fermentation for the production of ethanol by 4 strains ofZymomonas mobilis (ATCC 10988, ATCC 12526, NRRL B 4286 and IFO 13756) were studied. An initial sugar concentration of 15 % (w/v) at pH 7.0 was found to be optimal for the first two strains and 20 % (w/v) initial sugar at pH 7.0 was found to be optimal for the last two strains. The fermentation pattern of these strains on synthetic medium, cane juice and molasses were compared. Strain NRRL B 4286 showed maximum ethanol production on synthetic medium while on cane juice ATCC 10988 and ATCC 12526 performed well. However, all the strains fermented molasses poorly.