Transglutaminase is essential in receptor-mediated endocytosis of alpha 2-macroglobulin and polypeptide hormones

The receptor-mediated endocytosis of alpha 2-macroglobulin can be inhibited by a diverse group of chemical compounds all of which share the property of being inhibitors of one form of cellular transglutaminase. The present results strongly suggest that protein cross-linking may be essential for receptor-mediated endocytosis of some protein and polypeptide hormones.     

Inside polyomavirus at 25-A resolution.

Empty capsids and complete virions of polyomavirus crystallize isomorphously. Here we use difference Fourier analysis of X-ray diffraction data at 25-A resolution from these crystals to obtain an electron-density map of the inside of the virion. The polyomavirus capsid is built from 72 pentamers of VP1 that form three different types of connections in the T = 7d icosahedral surface lattice. Self-assembly of purified recombinant VP1 into capsid-like aggregates has shown that switching of the bonding specificity to form the unanticipated non-equivalent connections is an inherent property of the VP1 pentamers. Our map of the inside of the virion displays 72 prongs of electron density extending from the core into the axial cavities of the VP1 pentamers. We identify these prongs with the VP2 and VP3 molecules, which may function to guide the assembly of the highly ordered capsid on the nucleohistone core. The atomic structure of the closely related simian virus-40 capsid has been determined from the high-resolution diffraction data. Our polyomavirus map, calculated using all the low-resolution diffraction data, shows no indication of regular order inside the spherical core.     

Selection Optimal Drill Rigs by Grey Relational Analysis Method

Based upon the main properties of the relational analysis in grey system theory,a newmethod to select optimal drill rigs is proposed in this paper.Under the unified technique economicindex,with the practical data of four kinds of drill rigs in the mining district,east of Sichuan,China,an optimal reference number series was constructed.Through calculating the relational grade     

Activation of old carbon by erosion of coastal and subsea permafrost in Arctic Siberia

The future trajectory of greenhouse gas concentrations depends on interactions between climate and the biogeosphere. Thawing of Arctic permafrost could release significant amounts of carbon into the atmosphere in this century. Ancient Ice Complex deposits outcropping along the ~7,000-kilometre-long coastline of the East Siberian Arctic Shelf (ESAS), and associated shallow subsea permafrost, are two large pools of permafrost carbon, yet their vulnerabilities towards thawing and decomposition are largely unknown. Recent Arctic warming is stronger than has been predicted by several degrees, and is particularly pronounced over the coastal ESAS region. There is thus a pressing need to improve our understanding of the links between permafrost carbon and climate in this relatively inaccessible region. Here we show that extensive release of carbon from these Ice Complex deposits dominates (57?±?2 per cent) the sedimentary carbon budget of the ESAS, the world’s largest continental shelf, overwhelming the marine and topsoil terrestrial components. Inverse modelling of the dual-carbon isotope composition of organic carbon accumulating in ESAS surface sediments, using Monte Carlo simulations to account for uncertainties, suggests that 44?±?10 teragrams of old carbon is activated annually from Ice Complex permafrost, an order of magnitude more than has been suggested by previous studies. We estimate that about two-thirds (66?±?16 per cent) of this old carbon escapes to the atmosphere as carbon dioxide, with the remainder being re-buried in shelf sediments. Thermal collapse and erosion of these carbon-rich Pleistocene coastline and seafloor deposits may accelerate with Arctic amplification of climate warming.