The establishment of two novel bovine cell lines by transfection with the putative transforming region of bovine adenovirus type 3

Human adenoviruses (Ads), members of the family adenoviridae, are medium-sized DNA viruses which have been used as valuable research tools for the study of RNA processing, oncogenic transformation, and for the development of viral vectors for use in gene delivery and immunization technology. The left 12% of the linear Ad genollle codes for products which are necessary for the efficient replication of the virus, as well as being responsible for the forlllation of tumors in animallllodels. The establishlllent of the 293 cell line, by immortalization of human embryonic kidney cells with th~ E1 region of Ad type S (AdS), has facilitated extensive manipulation of the Ads and the development of recombinant Ad vectors. The study of bovine adenoviruses (BAVs), which cause mild respiratory and gastrointestinal infections in cattle has, on the other hand, been limited primarily to that of infectivity, immunology and clinicallllanifestations. As a result, any potential as gene delivery vehicles has not yet been realized. Continued research into the molecular biolo~gy of BAVs and the development of recolllbinant vectors would benefit from the development of a cell line analogous to that of the 293 cells. In an attelllpt to establish such a cell line, the recombinant plaslllid pKC-neo was constructed, containing the left 0-19.7% of the BAV type 3 (BAV3) genome, and the selectable marker for resistance to the aminoglycoside G418, a neomycin derivative. The plasmid construct was then used to transfect both the Madin-Darby bovine kidney (MDBK) -iicell line and primary bovine lung cells, after which G418-resistant foci were selected for analysis. Two cell lines, E61 (MDBK) and E24 (primary lung), were subsequently selected and analysed for DNA content, revealing the presence of the pKC-neo sequences in their respective genomes. In addition, BAV3 RNA transcripts were detected in the E61 cells. Although the presence of E1 products has yet to be confirmed in both cell lines, the E24 cells exhibit a phenotype characteristic of partial transformation by E1. The apparent immortalization of the primary lung cells will permit exploitation of their ability to take up exogenous DNA at high efficiency.

Interaction between stress and immunity during a week leading to competition in young athletes

This study examined changes in the salivary concentrations of immunoglobulin A (sIgA), cortisol (sC), testosterone (sT) and testosterone-to-cortisol ratio (T/C) in 23 competitive swimmers, 11-15 years old, during a week leading to competition as compared to a control (non-competitive) week. Results showed no effect of week or day, and no significant week-by-day interaction for sIgA, sC and T/C. In contrast, sT significantly decreased during the week of competition, along with a 7%, non-significant decrease in the weekly T/C. The latter suggests that the swimmers were in a catabolic state due to their training, but this did not have a negative effect on their performance Since sC did not change over the two weeks and according to the sport anxiety scale, competition stress was relatively low in these peri-pubertal athletes, it is concluded that in the absence of high cortisol levels mucosal immunity is unaffected in young athletes prior to competition.

Synthesis of 3', 5'-cyclic diguanylic acid (c-di-GMP) analogues

In the past few years, interest in signaling networks involving 3ʹ, 5ʹ -cyclic diguanylic acid (c-di-GMP) has increased dramatically. Evidence started to emerge that connects c-di-GMP to the regulation of a range of biological processes in bacteria, such as bacterial biofilm formation, virulence, extracellular polysaccharide synthesis, however, much remains to be explored in the signaling pathways that involve this secondary messenger. This molecule has also been shown to be a very powerful immunostimulating agent and potent mucosal vaccine adjuvant.