Genotypes of Pestivirus RNA detected in anti-influenza virus vaccines for human use

Nine polyvalent human influenza virus vaccines were tested by reverse transcriptase-polymerase chain reaction (RT-PCR) for the presence of pestivirus RNA. Samples were selected from manufacturers in Europe and the USA. Three samples of the nine vaccines tested (33.3%) gave positive results for pestivirus RNA. The 5'-untranslated genomic region sequence of the contaminant pestivirus RNA was analysed based on primary nucleotide sequence homology and on secondary sequence structures characteristic to genotypes. Two sequences belonged to Pestivirus type-1 (bovine viral diarrhoea virus [BVDV]) species, genotypes BVDV-1b and BVDV-1e. These findings confirm previous reports, suggesting an improvement in preventive measures against contamination of biological products for human use.

Identification and characterization of the mre gene region of Streptomyces coelicolor A3(2)

During a search for new differentiation factors in Streptomyces coelicolor A3(2), a locus at 11 o'clock on the S. coelicolor map was identified which harbours several genes that show extensive similarity to cell division and differentiation genes from Escherichia coli and Bacillus subtilis. From the sequence data it was concluded that the region contains the genes mireB, mreC, mreD (murein formation gene cluster E), pbp83 (high-molecular-weight penicillin-binding protein) and sfr (member of the spoVE/ftsW/rodA family). Mre gene products are reported to be responsible for determining cell shape in E. coli and Bacillus. The S. coelicolor mreC gene was inactivated by gene disruption, resulting in mutants which showed significant growth retardation in comparison to the wild type. Inactivation of the mreB gene was incompatible with viability, and thus mreB represents a Streptomyces cell division gene that is essential for survival. Promoter-probe experiments led to the identification of an operon structure, with promoters located upstream of mreB, pbp83 and sfr. Detailed studies of mreB transcription revealed the existence of three promoters; two of them are constitutively transcribed, whereas the third is developmentally regulated.

A preliminary assessment of the feasibility of evaluating promising antifilarials in vitro against adult Onchocerca volvulus

The suitability of motility indices and tetrazolium-based colorimetric assays for the determination of the viability of adult Onchocerca volvulus after in vitro exposure to potential macrofilaricides has been examined. Experimentation showed that both techniques could be applied to adult O. volvulus, although the variability between individual worms necessitated the use of large experimental groups. The potential of using cut anterior tips of female O. volvulus for screening was also investigated. These were shown to give reasonably consistent motility indices, and drug effects were discernible even after 72 h in vitro culture. Application of these viability criteria to studies on the short-term in vitro survival of intact male and female O. volvulus incubated in Eagles MEM plus serum, under 5% CO2 in air, showed this medium to be suboptimal with a greater than 50% loss of worm viability within 144 h of nodulectomy. Males isolated by the collagenase technique were shown to be significantly less viable than dissected males, by both motility indices and tetrazolium reduction. The results highlight the need to use either dissected males, or in the case of females, the need to minimize exposure to collagenase solution. A possible mechanism for selecting a more uniformly viable female worm population is discussed. Examination of the in vitro effects of CGP 20376 using these viability criteria/assay systems showed some delayed suppression of worm motility, but after 120 h in vitro CGP 20376 was not macrofilaricidal against male or female O. volvulus. Male worms were also implanted subcutaneously into gerbils.(ABSTRACT TRUNCATED AT 250 WORDS)