Purification and characterization of avian encephalomyelitis virus

Avian encephalomyelitis virus-infected chick embryo homogenate was precipitated with polyethyleneglycol 6000 (PEG), extracted with fluorocarbon, concentrated by ultrafiltration, and purified by isopycnic gradient centrifugation. The physical and chemical properties of the purified virus were studied. The examination of purified avian encephalomyelitis virus (AEV) with electron microscopy using negative stain revealed virus particles which were icosahedral in shape, lacked an envelope, and had a mean diameter of 26 ± 3 nm. It was suggested that the viral capsid was composed of 12 capsomers located at the vertices of an icosahedron. The virus was tentatively given a triangulation number of one, and included in the icosahedral class P = 1. The sedimentation coefficient (S₂₀, w) of AEV was determined to be 148 ± 3 S. The bouyant density of the virus in CsC1 was determined to be 1.31 to 1.32 g/ml by infectivity assay following isopycnic gradient centrifugation. The infectivity titer of the virus was reduced by 1.2 log₁₀ after heating at 56 °C for one hour. The virus was stabilized to the effect of heat by 1 M MgCl₂ The virus was resistant to treatment with chloroform and trypsin. Attempts to discern the type of nucleic acid in the virus genome were inconclusive

Evaluation of lipoprotein size–density distributions from sedimentation coefficient distributions obtained at several solvent densities. I. Theory

A method is presented for the treatment of distribution functions obtained by ultra-centrifugal sedimentation velocity experiments on the plasma lipoproteins, so that adequate corrections can he made for the effects of diffusion and concentration dependence of the sedimentation coefficient. The method involves the use of modified equations derived from those presented in 1952 by Gosting for the transform from g* ( S ) to g( S ) distributions. The evaluation of the molecular parameters of lipoprotein density and size, from a set of g( S i °) distribution functions obtained in solvents of varying density, is also outlined. Preparations of the Β-lipoprotein of human plasma are found to follow a bivariate normal distribution that requires evaluation of five parameters, x 1 , Σ 1 , x 2 , Σ 2 and p . The first two represent the mean and standard deviation of the lipoprotein density, the third and fourth the same quantities for the size, expressed as ft “logarithmic diameter parameter”, and the final value is a measure of the correlation between these two variables.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/37824/1/360070112_ftp.pd

Aledb 1.0: A database of mutations from adaptive laboratory evolution experimentation

Adaptive Laboratory Evolution (ALE) has emerged as an experimental approach to discover causal mutations that confer desired phenotypic functions. ALE not only represents a controllable experimental approach to systematically discover genotype-phenotype relationships, but also allows for the revelation of the series of genetic alterations required to acquire the new phenotype. Numerous ALE studies have been published, providing a strong impetus for developing databases to warehouse experimental evolution information and make it retrievable for large-scale analysis. Here, the first step towards establishing this resource is presented: ALEdb (http://aledb.org). This initial release contains over 11 000 mutations that have been discovered from eleven ALE publications. ALEdb (i) is a web-based platform that comprehensively reports on ALE acquired mutations and their conditions, (ii) reports key mutations using previously established trends, (iii) enables a search-driven workflow to enhance user mutation functional analysis through mutation cross-reference, (iv) allows exporting of mutation query results for custom analysis, (v) includes a bibliome describing the databased experiment publications and (vi) contains experimental evolution mutations from multiple model organisms. Thus, ALEdb is an informative platform which will become increasingly revealing as the number of reported ALE experiments and identified mutations continue to expand

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