Bacillus piliformis (Tyzzer) was isolated from the liver of rabbits with Tyzzer's disease and serially passaged in embryonated hens' eggs. Weanling rabbits given the 32nd egg passage developed lesions typical of Tyzzer's disease and died. B. piliformis was reisolated from the liver of these rabbits in embryonated eggs. Outside the host cell, the motile vegetative phase appeared to be unstable, ...

We passaged cells expressing TEM-1 and TEM-12 from a single plasmid through either ampicillin or ceftazidime. We found that the combined effects of recombination and selection removed the bla(TEM-1) allele from the bacterial population when it was passaged through ceftazidime or the bla(TEM-12) allele when cultures were passaged through ampicillin.

Avian infectious bronchitis is an acute and highly contagious disease that mainly causes respiratory symptoms in poultry. A number of serotypes and variants of the viral agent with poor cross-protection are the major problem to achieve desired immunity from vaccination. The S1 subunit of S glycoprotein (spike) is the major determinant of IBV so that a minor change in amino acid sequence of this...

Substitutions at the receptor-binding site of the pandemic H1N1 2009 influenza A virus (H1N1pdm) hemagglutinin (HA) gene may be critical in determining whether a virus binds to human or avian receptors. Previous reports suggest that HA Gly(222) and/or Arg(223) allow viruses to bind preferentially to the α2,3-linked sialic acid found in avian species. We also demonstrated that serial passaging o...

Low pathogenic avian influenza (LPAI) H9N2 viruses have been circulating in the Eurasian poultry industry resulting in great economic losses due to declined egg production and moderate to high mortality. In Korea, H9N2 LPAI was first documented in 1996 and it caused serious economic loss in the Korean poultry industry, including layer and broiler breeder farms. Since then, the H9N2 viruses that...

It has been attempted in this laboratory for the past years to isolate and passage herpes simplex virus by the chorioallantoic inoculation of embryonated eggs and pursue the changes in pathogenicities for various host animals occurring during the course of the passage. Among the pathogenicities examined were included those for baby mice intracerebrally or intraperitoneally inoculated, since Kil...

Mosquito-borne alphaviruses, which replicate alternately and obligately in mosquitoes and vertebrates, appear to experience lower rates of evolution than do many RNA viruses that replicate solely in vertebrates. This genetic stability is hypothesized to result from the alternating host cycle, which constrains evolution by imposing compromise fitness solutions in each host. To test this hypothes...

INTRODUCTION Avian influenza viruses of the H9N2 subtype have been reported to cause human infections. This study demonstrates the impact of nasal viral passaging of avian H9N2 in hamsters on its cross species-pathogenic adaptability and variability of amino acid sequences of the hemagglutinin (HA) and neuraminidase (NA) stalk. METHODOLOGY Three intranasal passagings of avian H9N2 in hamsters...

An in vivo-passaged strain of Mycoplasma hyopneumoniae attained viability titers of 10(6) to 10(8) color-changing units per mg of tissue in pig lungs and caused gross and histological pulmonic lesions. Mycoplasmas were readily located in the lumina of the respiratory tract by electron microscopy. In sections of tissue fixed in glutaraldehyde-osmium, the organisms were found to possess many radi...