MATHEMATICS: Taking the Measure of the Wildest Dance on Earth

By exploiting the symmetry of randomness, three mathematicians have revealed the geometric underpinnings of the frenetic random dance called Brownian motion. The methods they used seem likely to apply to other random processes, some as familiar as the flow of water through a filter. The proof was presented at the recent Current Developments in Mathematics 2000 conference sponsored by Harvard University and the Massachusetts Institute of Technology.     

Chronic infection of rodents by Machupo virus

Machupo virus, the etiologic agent of human hemorrhagic fever in Bolivia, induced chronic asymptomatic infection in laboratory hamsters and colonized individuals of the peridomestic, wild, South American rodent, Calomys callosus. Viruria was detected for more than 500 and 150 days, respectively, in the two species. Chronic viremia was shown only for Calomys. Virus-neutralizing substances were present in parenterally infected adult animals, but not in animals born to, and in contact with, an infected female. Chronic infection in wild rodents may be an important mechanism in the natural history of Machupo and related virus infections.     

Differences in denaturation of genetic variants of soy glycinin

In heat denaturation studies conducted in the past the genetic variants of glycinin have been considered as a homogeneous group of proteins. In this work the validity of this assumption was tested. It was found by calorimetric studies that glycinin denatures heterogeneously at pH 7.6. When the temperature of isothermal treatment is increased from 70 to 82 degrees C the proportion of glycinin remaining native progressively decreases from 95% to 5% while the denaturation temperature of the glycinin remaining native increases from 88.5 to 95 degrees C. Similar trends were found for pH 3.8. Fractionation and subsequent analysis (MALDI-TOF and CE) of isothermally treated samples demonstrated that at pH 7.6 the heterogeneous denaturation is caused by differences in thermal stability of the genetic variants of glycinin. The stability increases in the order G2/G3/G1< A(4)< G5 < G4.