Effect of aerosol age on the infectivity of airborne Pasteurella tularensis for Macaca mulatta and man

Sawyer, William D. (U.S. Army Medical Unit, Fort Detrick, Frederick, Md.), Joseph V. Jemski, Arthur L. Hogge, Jr., Henry T. Eigelsbach, Elwood K. Wolfe, Harry G. Dangerfield, William S. Gochenour, Jr., and Dan Crozier. Effect of aerosol age on the infectivity of airborne Pasteurella tularensis for Macaca mulatta and man. J. Bacteriol. 91:2180-2184. 1966.-In aging aerosols of Pasteurella tularensis SCHU-S4, the respiratory infectivity for man and Macaca mulatta decreased more rapidly than the viability of the organisms. Infectivity was diminished after 120 min, and was reduced 10-fold after 180 min. These findings confirmed previous observations made in mice and guinea pigs, and also revealed that smaller losses of infectivity were detectable in the primate hosts.     

A sampling theory for local selection

We have examined a model of selection (local selection) in which successive favorable alleles enter into a population by displacing a random fraction of each of the preexisting alleles. When the distribution of fitness among newly arising favorable mutations is given by a power law, then the distribution of allele frequencies in the population converge to a Poisson-Dirichlet limit, and the sampling distribution of alleles is a Ewens distribution. This property leads to a convenient algorithm for simulating random equilibrium frequencies of alleles within samples. The model can also be interpreted in terms of species abundances when each invading species displaces a random fraction of each pre-existing species, or in terms of age structures in populations subjected to random catastrophes.     

Parathyroid hormone preparations, salmon calcitonin, and urine flow in the South American lungfish, Lepidosiren paradoxa.

In the South American lungfish, Lepidosiren paradoxa, injections of salmon calcitonin or bovine parathyroid extract have no effect on serum calcium levels. However, salmon calcitonin elicits a distinct diuresis. Crude or purified parathyroid extract or synthetic parathyroid hormone (1-34 fraction) produce a distinct antidiuresis.     

Segmented linear regression models applied to the analysis of data from a cross-sectional growth experiment

Several different methods of analysis are applied to data consisting of weight measurements, taken at specified post-treatment times, of harvested thyroids from rats given one of four treatments. Previous studies of this type of data indicated that the growth is initially rapid, and that a second phase of less rapid growth is followed by a final phase in which little additional growth occurs. The data are further characterized by increasing variance through time. The primary purpose of the analysis is to study the effect of the treatments at the end of the study period. One-way analysis of variance tests among groups are performed on each day, but the results are not particularly helpful. However, results from two-way analyses of variance (over subsets of days and groups) are consistent with the three phase model and accordingly indicate significant group differences during each. Finally, maximum likelihood methods are used to fit a three part segmented linear regression model.     

Identification, expression, and localization of β keratin gene products during development of avian scutate scales

Epidermal-dermal interactions influence morphogenesis and expression of the beta keratin gene family during development of scales in the embryonic chick. The underlying mechanisms by which these interactions control beta keratin expression are not understood. However, the present study of beta keratin gene expression during avian epidermal differentiation contributes new information with which to investigate the role of tissue interactions in this process. Using beta keratin-specific synthetic oligonucleotide probe, beta keratin mRNA was hybrid-selected from total poly A+ RNA of scutate scales. Seven beta keratin polypeptides were translated in vitro and could be identified by their positions in two-dimensional gels among the detergent-insoluble extracts of scutate scale epidermis. In vivo phosphorylation studies suggested that an additional three beta keratin polypeptides were present as phosphoproteins. The temporal appearance of beta keratin mRNA and the corresponding polypeptides was followed during scutate scale development. Polyclonal antiserum made against two of the beta keratin polypeptides was used for immunohistochemical and immunogold electron-microscopic analysis of beta keratin tissue distribution. Immunological reactivity was observed specifically along the outer scale surface in epidermal cells above the stratum germinativum. Immunogold beads were localized on 3-nm filament bundles. In situ hybridization with a beta keratin-specific RNA probe demonstrated that mRNA accumulated in the same regional manner as the polypeptides. This selective expression of beta keratin genes in specific regions of the developing scutate scale suggests that epidermal-dermal interactions provide not only for morphological events, but also for control of complex patterns of histogenesis and biochemical differentiation.