The periplasmic flagella of Serpulina (Treponema) hyodysenteriae are composed of two sheath proteins and three core proteins.

The major components of the periplasmic flagella of the spirochaete Serpulina (Treponema) hyodysenteriae strain C5 were purified and characterized. We demonstrate that the periplasmic flagella are composed of five major proteins (molecular masses 44, 37, 35, 34 and 32 kDa) and present their location, N-terminal amino acid sequence and immunological relationship. The 44 kDa and the 35 kDa protein are on the sheath of the periplasmic flagellum, whereas the 37, 34 and 32 kDa protein reside in the periplasmic flagellar core.

Cloning and DNA sequence analysis of a Serpulina (Treponema) hyodysenteriae gene encoding a periplasmic flagellar sheath protein.

A Serpulina (Treponema) hyodysenteriae expression library was constructed in vector lambda ZAP and screened with a polyclonal antiserum raised against S. hyodysenteriae periplasmic flagella. A single immunoreactive plaque was chosen for further analysis.

Location of antigenic sites defined by neutralizing monoclonal antibodies on the S1 avian infectious bronchitis virus glycopolypeptide.

Neutralizing monoclonal antibodies directed against five antigenic sites on the spike (S) S1 glycopolypeptide of avian infectious bronchitis virus (IBV) were used to select neutralization-resistant variants of the virus. By comparing the nucleotide sequence of such variants with the sequence of the IBV parent strain, we located five antigenic sites on the amino acid sequence of the S1 glycopolypeptide. The variants had mutations within three regions corresponding to amino acid residues 24 to 61, 132 to 149 and 291 to 398 of the S1 glycopolypeptide.

Cloning and expression of a Serpula (Treponema) hyodysenteriae hemolysin gene.

Serpula (Treponema) hyodysenteriae, the etiologic agent of swine dysentery, produces a hemolysin which is thought to be an important factor in the pathogenesis of the disease. We report the cloning, sequencing, and expression of a hemolysin gene (tly) from S. hyodysenteriae B204.

Rapid detection and identification of avian infectious bronchitis virus.

A rapid and sensitive method for the detection and unambiguous typing of infectious bronchitis virus (IBV) is described. RNA was isolated from IBV-infected allantoic fluid and was transcribed into cDNA. This cDNA was amplified by the polymerase chain reaction.

Localization of a T-cell epitope within the nucleocapsid protein of avian coronavirus.

In a previous study, two murine T-cell hybridomas generated after immunization with infectious bronchitis virus (IBV) were shown to be responsive to the internally localized viral nucleocapsid protein. In the present study, the antigenic determinants were mapped using recombinant expression products and synthetic peptides. Both hybridomas recognized the region spanning amino acid residues 71 to 78 of the nucleocapsid protein.

Conserved nucleotide sequences at the 5' end of T cell receptor variable genes facilitate polymerase chain reaction amplification.

Alignment of all available nucleotide sequences of mouse and rat alpha/beta T cell receptor (TcR) variable (V) regions revealed the presence of relatively conserved sequences at the 5' end of the V gene segments. Based on these conserved sequences, degenerate primers were developed for use in the polymerase chain reaction (PCR). The degenerate primers developed on the basis of the conserved sequences at the 5' end of rat and mouse V gene segments are expected to enable the amplification of all mouse and rat TcR alpha/beta chain V regions.

Hysteresis in quartz resonators-a review.

The literature on the frequency versus temperature characteristics of quartz crystal resonators is reviewed. Three papers that deal with frequency versus pressure hysteresis are included, as these may possibly have relevance to frequency versus temperature hysteresis. It is seen that the causes of hysteresis are not well understood.

MHC class II-restricted T-cell hybridomas recognizing the nucleocapsid protein of avian coronavirus IBV.

Mice were immunized with purified infectious bronchitis virus (IBV), strain M41. Spleen cells, expanded in vitro by stimulation with M41, were immortalized by fusion to obtain T-cell hybridomas, and two major histocompatability complex (MHC) class II (I-E)-restricted T-cell hybridomas were selected with specificity for IBV. Both hybridomas selectively recognized the internal nucleocapsid protein.

Sequence evidence for RNA recombination in field isolates of avian coronavirus infectious bronchitis virus.

Under laboratory conditions coronaviruses were shown to have a high frequency of recombination. In The Netherlands, vaccination against infectious bronchitis virus (IBV) is performed with vaccines that contain several life-attenuated virus strains. These highly effective vaccines may create ideal conditions for recombination, and could therefore be dangerous in the long term.

Mapping of viral epitopes with prokaryotic expression products.

Several systems are available for the expression of foreign gene sequences in Escherichia coli. We describe the use of prokaryotic expression products of viral gene fragments in order to identify the regions that specify the binding sites of antibodies. This approach is particularly successful if the antigenicity does not depend on the native protein, but only on the amino acid sequence, i.

Analysis of an immunodominant region of infectious bronchitis virus.

We analyzed the antigenic fine-structure of an immunodominant region in the peplomer protein of infectious bronchitis virus. This region near the N-terminus of the S2 subunit is recognized by polyclonal antisera and by the majority of mAb that cross-react with denatured protein. Despite their involvement in neutralization, epitopes in this region were conserved in different serotypes.

The nucleotide sequence of the first two genes of the CFA/I fimbrial operon of human enterotoxigenic Escherichia coli.

An oligonucleotide probe, derived from the N-terminal amino acid sequence of the CFA/I fimbrial subunit protein, was used to identify the gene encoding this protein within a cloned DNA fragment encoding CFA/I fimbriae. The gene (cfa b) was found and sequenced. Flanking it upstream was a gene (cfa a) encoding a protein of 206 amino acids and downstream a gene (cfa c) probably encoding an 85 kDa protein was found.

Phylogeny of antigenic variants of avian coronavirus IBV.

The sequences of the peplomeric S1 protein of four serologically distinct strains of the infectious bronchitis virus (IBV), an avian coronavirus, have been determined. The S1 protein is thought to contain the serotype-specific neutralization epitopes and to be the main target of antigenic variation. An alignment with sequences of three strains published previously showed that from the 545 amino acid residues only 243 have been conserved.

Spatial weighting in laboratory incoherent light scattering experiments.

Diffraction-based calculations of the relative spatial weighting of the observed volume in incoherent scattering experiments, applicable to both direct detection and heterodyne systems and arbitrary transmitter and receiver profiles, have been largely confirmed in laboratory measurements using a CO(2) laser. The results indicate that heterodyne systems have superior spatial resolution at small scattering angles for a given detector geometry and permit quantitative assessment of this and the greater sensitivity of coherent systems to misalignment.

Antigenicity of the peplomer protein of infectious bronchitis virus.

To study the antigenic structure of the peplomer protein of the avian coronavirus infectious bronchitis virus, fragments from the peplomer gene were generated by restriction-enzyme cleavage or by limited DNase digestion and inserted in the Escherichia coli expression plasmid pEX (Stanley and Luzio, 1984). The antigenicity of the expression products was tested using a number of polyclonal antisera and monoclonal antibodies. The polyclonal antisera recognized different sets of epitopes in the 1162-residue sequence.

Synthesis of long cDNA from viral RNA template.

Methods to make long and reliable cDNA from viral RNA template have been optimized. The conditions of the denaturation of the viral RNA template were most critical. For synthesis of the first DNA strand, the concentration of the primer and the presence of an RNase inhibitor were important.

Molecular epidemiology of infectious bronchitis virus in The Netherlands.

Twelve Dutch isolates and the M41 strain of infectious bronchitis virus (IBV), a coronavirus of chickens, were characterized by cross-neutralization and T1 finger-printing to elucidate their evolutionary relationship. The T1 fingerprinting showed that the Dutch isolates formed two clusters. The first cluster contained strains H52, H120, D387, V1259, V1385 and V1397; the estimated sequence homology is 99%.