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H SCHNEIDER

Publications and source records attributed to H SCHNEIDER.

At least 37 records · Page 2Linked to original sources
PubMed1963

Experimental Shigella infections. VI. Role of the small intestine in an experimental infection in guinea pigs.

Formal, Samuel B. (Walter Reed Army Institute, Washington, D.C.), G. D. Abrams, H. Schneider, and H. Sprinz. Experimental Shigella infections. VI. Role of the small intestine in an experimental infection in guinea pigs. J. Bacteriol. 85:119-125. 1963.-Shigella infection under the conditions of our experiment significantly involves the small intestine, producing lesions similar to those seen in human acute small intestinal dysentery. Previous work established that, for a rapidly fatal infection to occur, animals had to be pretreated by starvation or by administration of carbon tetrachloride, and, after oral challenge with S. flexneri, had to receive opium. Data are presented indicating that, in the guinea pig, the motility of the small intestine is a major defense mechanism in clearing bacteria from the gut. It is concluded that the two modes of pretreatment potentiate the ability of opium to decrease this motility, and hence increase susceptibility to enteric infection.

Animals↗
PubMed1963

VIRULENCE OF ESCHERICHIA-SHIGELLA GENETIC HYBRIDS FOR THE GUINEA PIG.

Falkow, Stanley (Walter Reed Army Institute of Research, Washington, D.C.), H. Schneider, L. S. Baron, and S. B. Formal. Virulence of Escherichia-Shigella hybrids for the guinea pig. J. Bacteriol. 86:1251-1258. 1963.-Genetic recombination studies between donor Escherichia coli and recipient Shigella flexneri 2a strains were employed to examine alterations in the virulence of Shigella hybrids for guinea pigs. The genetic studies indicated that several chromosomal regions of E. coli and S. flexneri are grossly homologous. The frequency of recombination between E. coli and Shigella was decreased, however, in comparison with E. coli x E. coli matings. Moreover, the predominant Shigella hybrid classes acquired only the selected genetic marker, and extensive transfer of the Escherichia genome was detected only occasionally. The virulence studies made use of hybrids with well-defined single markers as well as those with overlapping chromosomal regions. Analysis of over one-half of the chromosome revealed only one chromosomal region, located between the rha(+) and xyl(+) genes, which was essential for virulence. However, hybrids which had received the E. coli pili antigen and fuc(+)-nic(+) determinants exhibited an intermediate virulence. Hybrids carrying a full complement of Shigella genes and the rha(+)-xyl(+)Escherichia region as a persistent exogenote (partial diploids) were of intermediate virulence. These partial diploids may return to complete virulence by elimination of the Escherichia chromosomal fragment or become avirulent by incorporation of this fragment.

Animals↗
PubMed1961

Experimental genetic recombination in vivo between Escherichia coli and Salmonella typhimurium.

Antibiotic-pretreated mice were fed orally an Hfr culture of streptomycin-resistant E. coli and 1 day later, a streptomycin-resistant F(-)S. typhimurium culture. Hybrids were recovered in relatively small numbers from the feces of these mice within 24 hours demonstrating that genetic recombination can occur within the intestinal tract of a mammalian host under experimental conditions. These hybrids multiplied rapidly and persisted throughout the course of the experiment. In addition, hybrids were recovered which had not been observed in single matings performed in vitro.

Animals↗