Improvement of bacterial transformation efficiency using plasmid artificial modification

We have developed a method to improve the transformation efficiency in genome-sequenced bacteria, using ‘Plasmid Artificial Modification’ (PAM), using the host's own restriction system. In this method, a shuttle vector was pre-methylated in Escherichia coli cells, which carry all the putative genes encoding the DNA modification enzymes of the target microorganism, before electroporation was performed. In the case of Bifidobacterium adolescentis ATCC15703 and pKKT427 (3.9 kb E. coli-Bifidobacterium shuttle vector), introducing two Type II DNA methyltransferase genes lead to an enhancement in the transformation efficiency by five orders of magnitude. This concept was also applicable to a Type I restriction system. In the case of Lactococcus lactis IO-1, by using PAM with a putative Type I methyltransferase system, hsdMS1, the transformation efficiency was improved by a factor of seven over that without PAM

A case of unusually early postpartum resumption of estrous cycling in a young female chimpanzee in the wild

A case of unusually early postpartum resumption of estrous cycling (<7 months) was recorded for a young, presumably primiparous female in the M group of chimpanzees (Pan troglodytes schweinfurthii) in the Mahale Mountains National Park, western Tanzania. The female showed estrous cycling while lactating her infant, and mated with young and low-ranking males as well as with the alpha male