Satellite tracking of ringed seals Phoca hispida off northwest Greenland

We monitored movements and haul-out patterns of four ringed seals Phoca hispida , off Northwest Greenland between 5 June and 31 October 1988 using the Argos Data Collection and Location System When the seals were hauled out on fast ice their locations were accurately determined, but when they were at sea, few accurate locations were obtained, evidently because these seals spent little time at the surface between dives The seals remained within the fjord where they were tagged, and hauled out often to early July Thereafter, as fast-ice disappeared, they dispersed widely and spent less time hauled out Time of day had no significant effect on haul-out patterns Haul-out periods declined significantly from June to August and increased in September-October Satellite contact with one seal was lost after 16 d while the seal was still in the fjord in late June One seal travelled over 200 km southwest and was located 4 July in offshore waters of Smith Sound 30 d after instrumentation Another seal moved southeast along the Greenland coast where contact was lost after 49 d on 23 July The fourth seal moved north along the Greenland coast, hauled out regularly on ice, and returned south along the coast in late September and October after 181 d of contact with the satellite     

The effect of a chemical soil sterilizing agent on the subsequent development of tomato plants

An account is given of the effect on the development of tomato plants of a chemical soil sterilizer containing orthodichlorbenzene and an emulsifying agent of the sulphonated oil type. The symptoms are described and an account is given of an experimental study of the effect of the treatment on growth and yield: the latter showed a considerable decrease. The injurious ingredient was shown to be orthodichlorbenzene.     

Expression and characterization of human lamin C

We have expressed human lamin C cDNA in E. coli using a modification of the pLcII vector system. Protein produced in this way had seven additional amino acids at its N-terminus, but retained key lamin structural and assembly properties. The modified vector we produced may prove useful when difficulties are encountered in removal of the cII fusion peptide by factor X cleavage in the pLcII system. Shadowed preparations of expressed lamin C showed the presence of 50-nm rod-like particles that closely resembled those observed for native material. Isolated molecules had two globular domains at one end, indicating that they were constructed from two parallel polypeptide chains. The expressed material also formed paracrystals with a characteristic 22.5 nm axial repeat, indicating that its assembly properties had also been retained. We also used site-specific mutagenesis to engineer a lamin fragment that lacked the C-terminal non-helical domain of the molecule. This material formed paracrystals similar to those obtained with the intact molecule, indicating that the large C-terminal non-helical domain did not contain information vital for lamin assembly.     

Interspecies chimeric conditions affect the developmental rate of human pluripotent stem cells

Human pluripotent stem cells hold significant promise for regenerative medicine. However, long differentiation protocols and immature characteristics of stem cell-derived cell types remain challenges to the development of many therapeutic applications. In contrast to the slow differentiation of human stem cells in vitro that mirrors a nine-month gestation period, mouse stem cells develop according to a much faster three-week gestation timeline. Here, we tested if co-differentiation with mouse pluripotent stem cells could accelerate the differentiation speed of human embryonic stem cells. Following a six-week RNA-sequencing time course of neural differentiation, we identified 929 human genes that were upregulated earlier and 535 genes that exhibited earlier peaked expression profiles in chimeric cell cultures than in human cell cultures alone. Genes with accelerated upregulation were significantly enriched in Gene Ontology terms associated with neurogenesis, neuron differentiation and maturation, and synapse signaling. Moreover, chimeric mixed samples correlated with in utero human embryonic samples earlier than human cells alone, and acceleration was dose-dependent on human-mouse co-culture ratios. The altered gene expression patterns and developmental rates described in this report have implications for accelerating human stem cell differentiation and the use of interspecies chimeric embryos in developing human organs for transplantation.