Pregnancy and parturition of mice latently infected with Pseudorabies virus.

In this study, the influence of pregnancy and parturition on mice in a mouse model of latent infection with Pseudorabies virus (PrV) was analyzed. Latently infected (LI) female mice were paired with mature uninfected males. The mating produced progeny without any clinical signs of Aujeszky's Disease. At weaning, both male and female progeny of LI mice showed significantly lower weight than control mice. PrV was not detected from nasal swab specimens of the female parent mice or the trigeminal ganglia of all mice, except 3 of 50 neonatal mice. These findings demonstrate that pregnancy and parturition induce little reactivation of latent PrV, but do affect the mother's body, as indicated by the decreased weight of progeny at weaning.     

Influence of substituent modifications on the binding of 2-amino-1,8-naphthyridines to cytosine opposite an AP site in DNA duplexes: thermodynamic characterization

Here, we report on a significant effect of substitutions on the binding affinity of a series of 2-amino-1,8-naphthyridines, i.e., 2-amino-1,8-naphthyridine (AND), 2-amino-7-methyl-1,8-naphthyridine (AMND), 2-amino-5,7-dimethyl-1,8-naphthyridine (ADMND) and 2-amino-5,6,7-trimethyl-1,8-naphthyridine (ATMND), all of which can bind to cytosine opposite an AP site in DNA duplexes. Fluorescence titration experiments show that the binding affinity for cytosine is effectively enhanced by the introduction of methyl groups to the naphthyridine ring, and the 1:1 binding constant (10⁶ M⁻¹) follows in the order of AND (0.30) < AMND (2.7) < ADMND (6.1) < ATMND (19) in solutions containing 110 mM Na⁺ (pH 7.0, at 20°C). The thermodynamic parameters obtained by isothermal titration calorimetry experiments indicate that the introduction of methyl groups effectively reduces the loss of binding entropy, which is indeed responsible for the increase in the binding affinity. The heat capacity change (ΔC_p), as determined from temperature dependence of the binding enthalpy, is found to be significantly different between AND (−161 cal/mol K) and ATMND (−217 cal/mol K). The hydrophobic contribution appears to be a key force to explain the observed effect of substitutions on the binding affinity when the observed binding free energy (ΔG_obs) is dissected into its component terms.     

In Vitro Proliferative Response and Polyclonal Antibody Production in Spleen Cells of Immunologically Defective CBA/N and C3H/HeJ Mice by Water-Soluble Adjuvant (Bu-WSA) Extracted from Bacterionema matruchotii

Mitogenicity and the polyclonal plaque forming cell(PFC)-inducing property of a water soluble-adjuvant extracted from Bacterionema matruchotii by butanol (Bu-WSA) were examined in vitro in the spleen cells of hybrid (CBA/N female × BALB/c male) F1 mice and C3H strain of mice. The hybrid F1 male cells which expressed a CBA/N-defect were unable to respond to Bu-WSA, when assessed by the incorporation of [³H] thymidine into the cells and the generation of anti-trinitrophenyl (TNP)-PFC or autoantibody PFC defined by the anti-bromel-ain-treated mouse erythrocyte PFC assay. However, hybrid F1 female cells with normal traits responded to Bu-WSA. Cultured spleen cells of bacterial lipopolysaccharide (LPS)-nonresponsive C3H/HeJ mice responded to Bu-WSA as in the case of cells of LPS-responsive C3H/He mice, and the [³H]thymidine-uptakes and the numbers of PFC in these culture cells increased. Re-extraction of Bu-WSA by phenol did not affect its activities, while the activity of butanol-extracted LPS on C3H/HeJ cells decreased after re-extraction by the same procedure with phenol.     

Protein Synthesis in the Isolated Forespores from Sporulating Cells of Bacillus subtilis

Developing forespores were isolated from Bacillus subtilis at different stages of sporulation and protein synthesis in the forespore compartment was examined. Pulse-labeling experiments indicated that [¹⁴C]phenylalanine was continuously incorporated into the sporangium throughout sporulation, and at t₅ (early stage V of sporulation) 58% of the radioactivity was located in the forespore compartment. Significantly high incorporation of [¹⁴C]phenylalanine was observed when the isolated forespores at t₅ were incubated with the corresponding mother-cell cytoplasmic fraction or an amino acid mixture. About 73% of the radioactivity incorporated into the isolated forespore at t₅ was found in the cytoplasmic fraction and 26% in the membranous fraction. Analysis by sodium dodecyl sulfate-gel electrophoresis showed that the ¹⁴C-labeled cytoplasmic protein had a molecular weight of about 20,000, and that a protein having the same molecular weight was present in the t₅ forespore as a slight protein band and also in the mature spore as a clear protein band. Gel electrophoresis also revealed that the ¹⁴C-labeled membranous-soluble protein (prepared by solubilization with detergents) had broad peaks with molecular weights of about 74,000, 33,000, 20,000, and 12,000.     

Scanning electron microscopic observation of the parasitic forms of Fonsecaea pedrosoi in a human skin lesion

The parasitic form of Fonsecaea pedrosoi in the superficial hyperkeratotic layer of the skin, in a patient with chromoblastomycosis, was observed by a scanning electron microscope using some technical improvements. The fungus elements were comprised of branched septate hyphae with spherical cells and sclerotic cells. It was observed that the sclerotic cells, divided into two or three parts, formed a germ tube.