Study on the Characteristics of Macromolecular Chains of Cellulose in Dilute Solutions

The characteristics of macromolecular chains of cellulose in dilute solutions are discussed. Viscometry was used for the measurement of the intrinsic viscosity [η] of four cellulose samples, which were respectively dissolved in the solvent Tri-ethylenediamine cadmium hydroxide Cadoxen (Cadoxen), Cupriethylenediamine hydroxide(Cuen), iron sodium tartrate complex(EWNN) and N,N-dimethylacetamide(DMAc)with lithium chloride(LiCI, 9% w/w). The intrinsic viscosity of the four solutions decreased in the following manner:[η]DMAc/LiCl>[η]EWNN>[η]Cuen>[η]Cadoxen. The stability of cellulose (Sample α-cellulose) dissolved in solvents Cuen and EWNN was tested by plotting the intrinsic viscosity vs. time. The values of Huggins constant K_H for the cellulose samples dissolved in solvents Cadoxen,Cuen,EWNN and DMAc/LiCl (9% w/w ) were calculated.     

Transferrin receptor 1 is a cellular receptor for New World haemorrhagic fever arenaviruses

At least five arenaviruses cause viral haemorrhagic fevers in humans. Lassa virus, an Old World arenavirus, uses the cellular receptor alpha-dystroglycan to infect cells. Machupo, Guanarito, Junin and Sabia viruses are New World haemorrhagic fever viruses that do not use alpha-dystroglycan. Here we show a specific, high-affinity association between transferrin receptor 1 (TfR1) and the entry glycoprotein (GP) of Machupo virus. Expression of human TfR1, but not human transferrin receptor 2, in hamster cell lines markedly enhanced the infection of viruses pseudotyped with the GP of Machupo, Guanarito and Junin viruses, but not with those of Lassa or lymphocytic choriomeningitis viruses. An anti-TfR1 antibody efficiently inhibited the replication of Machupo, Guanarito, Junin and Sabia viruses, but not that of Lassa virus. Iron depletion of culture medium enhanced, and iron supplementation decreased, the efficiency of infection by Junin and Machupo but not Lassa pseudoviruses. These data indicate that TfR1 is a cellular receptor for New World haemorrhagic fever arenaviruses.