Evolution of peptides that modulate the spectral qualities of bound, small-molecule fluorophores.

Background: Fluorophore dyes are used extensively in biomedical research to sensitively assay cellular constituents and physiology. We have created, as proof of principle, fluorophore dye binding peptides that could have applications in fluorescent dye-based approaches in vitro and in vivo.

Results: A panel of Texas red, Rhodamine red, Oregon green 514 and fluorescein binding peptides, termed here 'fluorettes', was selected via biopanning of a combinatorial library of 12-mer peptides fused to a minor coat pIII protein of the filamentous bacteriophage M13.

Interference of reovirus strains occurs between the stages of uncoating and dsRNA accumulation.

Interference of wild-type reovirus growth by some temperature-sensitive (ts) mutant viruses under non-permissive conditions or by other wild-type isolates has been demonstrated; however, the stage of the virus replication cycle at which interference occurs has not been defined. Examination of the time-course of the yields of T1 Lang (T1L) dsRNA in the progeny of mixed infections of T1L with T3 Dearing (T3D) or with a panel of T3D ts mutants at a non-permissive temperature revealed that interference takes place by 8-10 h post-infection and occurs prior to or at the same time as accumulation of reovirus dsRNA. Taken together with our previous results, these data indicate that interference occurs during a window between virus uncoating and synthesis of dsRNA in the reovirus replication cycle, probably at the stage of assembly of primary reovirus particles.

Evidence for phenotypic mixing with reovirus in cell culture.

From pairwise mixed infections of different reovirus wild-type isolates (T3 Dearing plus T1 Lang or plus T2 Jones) the progeny virus is phenotypically mixed, i.e., progeny viral particles contain proteins derived from both parents but the corresponding genes derived from only one parent.

Interference following mixed infection of reovirus isolates is linked to the M2 gene.

Following infection by pairs of reovirus isolates consisting of combinations of reovirus T1 Lang, T2 Jones, or T3 Dearing, we found that one of the isolates interfered with the yield of progeny RNA derived from the other parents. The most significant interference was produced by T2 Jones or T3 Dearing, when mixed with T1 Lang. Genetic analysis revealed that the presence of the M2 gene in the interfering parent (in the T1 Lang x T3 Dearing pair) was linked to interference.

All species of the genus Bordetella contain genes for pertussis toxin of Bordetella pertussis.

A molecular probe for the PT-operon of B. pertussis hybridized with 4.7 Kb EcoRI-fragments of chromosomal DNAs of B.