The effects of time of equilibration with cryoprotectants at 0 degree C prior to freezing on the survival of mouse embryos frozen by the two-step method

Mouse embryos were frozen by the two-step method after equilibration for 0.1-60 min with cryoprotectants at 0 degree C. No survival or a very low survival was obtained after equilibration for only 0.1 min. The morulae showed the highest survival rates when equilibration time was 5-30 min with 2 M DMSO, 20-30 min with 2 M glycerol, 5-10 min with 2 M ethylene glycol and 20-30 min with 2 M propylene glycol, respectively.     

Common variants in DVWA on chromosome 3p24.3 are associated with susceptibility to knee osteoarthritis

Susceptibility to osteoarthritis, the most common human arthritis, is known to be influenced by genetic factors. Through a genome-wide association study using approximately 100,000 SNPs, we have identified a previously unknown gene on chromosome 3p24.3, DVWA, which is associated with susceptibility to knee osteoarthritis. Expressed specifically in cartilage, DVWA encodes a 276-amino-acid protein with two regions corresponding to the von Willebrand factor type A domain (VWA domain). Several DVWA SNPs are significantly associated with knee osteoarthritis in two independent Japanese case-control cohorts. This association was replicated in a Japanese population cohort and a Han Chinese case-control cohort (combined P = 7.3 x 10(-11)). DVWA protein binds to beta-tubulin, and the binding is influenced by two highly associated missense SNPs (rs11718863 and rs7639618) located in the VWA domain. The Tyr169-Cys260 isoform of DVWA, which is overrepresented in knee osteoarthritis, showed weaker interaction. Our findings reveal a new paradigm for study of osteoarthritis etiology and pathogenesis.     

Formation of enantiomeric sesquiterpenes in the secretions of scale insects

Summary The volatile oil present in the secretion of a scale insect,Ceroplastes ceriferus Anderson (fam. Coccidae), has been found to consist of a number of sesquiterpenes which are enantiomeric with respect to those fromC. rubens Maskell, which infests the same host tree. The present investigation strongly suggests that each insect possesses a specific set of C-C cyclases for the sesquiterpenoids.Acknowledgments. The authors would like to express their thanks to Dr Y. Asakawa (Tokushima Bunri Univ.) for providingC. ceriferus and to Prof. S. Takagi (Hokkaido Univ.) for the identification of it.     

Effects of the temperature of ice-seeding on survival of frozen-and-thawed mouse morulae

Summary Mouse morulae were frozen to –196°C in the presence of 1.2 M ethylene glycol or 1 M glycerol. After iceseeding in embryo samples at –10°C or below, the survival rates in vitro were lower than those obtained by ice-seeding between –4° and –8°C. The proportion morulae developing into live young in vivo after ice-seeding at –13°C and freezing was lower than that of embryos seeded at –4°C.     

Cell-fate conversion of lymphoid-committed progenitors by instructive actions of cytokines

The primary role of cytokines in haemato-lymphopoiesis is thought to be the regulation of cell growth and survival. But the instructive action of cytokines in haematopoiesis has not been well addressed. Here we show that a clonogenic common lymphoid progenitor, a bone marrow-resident cell that gives rise exclusively to lymphocytes (T, B and natural killer cells), can be redirected to the myeloid lineage by stimulation through exogenously expressed interleukin (IL)-2 and GM-CSF (granulocyte/macrophage colony-stimulating factor) receptors. Analysis of mutants of the beta-chain of the IL-2 receptor revealed that the granulocyte- and monocyte-differentiation signals are triggered by different cytoplasmic domains, showing that the signalling pathway(s) responsible for these unique developmental outcomes are separable. Finally, we show that the endogenous myelomonocytic cytokine receptors for GM-CSF and macrophage colony-stimulating factor (M-CSF) are expressed at low to moderate levels on the more primitive haematopoietic stem cells, are absent on common lymphoid progenitors, and are upregulated after myeloid lineage induction by IL-2. We conclude that cytokine signalling can regulate cell-fate decisions and propose that a critical step in lymphoid commitment is downregulation of cytokine receptors that drive myeloid cell development.