Tolerance of the freeze-dried mouse sperm nucleus to temperatures ranging from −196 °C to 150 °C

It has long been believed that tolerance against extreme environments is possible only for ‘lower’ groups, such as archaea, bacteria or tardigrades, and not for more ‘advanced’ species. Here, we demonstrated that the mammalian sperm nucleus also exhibited strong tolerance to cold and hot temperatures. When mouse spermatozoa were freeze-dried (FD), similar to the anhydrobiosis of Tardigrades, all spermatozoa were ostensibly dead after rehydration. However, offspring were obtained from recovered FD sperm nuclei, even after repeated treatment with conditions from liquid nitrogen to room temperature. Conversely, when FD spermatozoa were heated at 95 °C, although the birth rate was decreased with increasing duration of the treatment, offspring were obtained even for FD spermatozoa that had been heat-treated for 2 h. This period was improved up to 6 h when glucose was replaced with trehalose in the freeze-drying medium, and the resistance temperature was extended up to 150 °C for short periods of treatment. Randomly selected offspring grew into healthy adults. Our results suggest that, when considering the sperm nucleus/DNA as the material that is used as a blueprint of life, rather than cell viability, a significant tolerance to extreme temperatures is present even in ‘higher’ species, such as mammals

Signal transduction mechanism of interleukin 6 in cultured rat mesangial cells

AbstractInterleukin 6 (IL-6) is one of the potent autocrine growth factors for mesangial cells. We investigated the signal transduction mechanism or IL-6 in cultured rat mesangial cells. IL-6 induced a transient increase of inositol 1,4,5-trisphosphate (Ins 1,4,5-P3) followed by a transient and sustained increase of intracellular calcium concentration, suggesting that IL-6 stimulates phosphoinositide turnover. IL-6 also stimulated prostaglandin E2 (PGE2) production. The IL-6-concentration dependency in PGE2 production was similar to that in Ins 1,4,5-P3 production. We concluded that the action of IL-6 on mesangial cells is exerted at least partially through the enhancement of phosphoinositide turnover and PGE2 production