A new membrane-bound OprI lipoprotein expression vector. High production of heterologous fusion proteins in gram (-) bacteria and the implications for oral vaccination

We have previously described the development of cloning vectors for the production of OprI-based outer membrane fusion proteins in E. coli (Cornelis et al., 1996) and now describe the construction of a new vector, containing a lacI(q) gene, resulting in tight repression of the promotor and allowing its use in other Gram (-) bacteria. The new pVUB3 expression vector encodes a truncated but active LacI(q)(341) repressor which binds to the single operator in the vector. A high repression of the trc promotor was observed, resulting in a very low basal leakage of expression and very high production levels of OprI or derivatives after IPTG induction in E. coli. Bacterial viability was not affected under uninduced conditions, but the number of viable cell counts decreased after production of large amounts of the outer membrane-bound OprI lipoprotein and its derivatives, both in E. coli and Salmonella typhimurium. This highly repressible system allows us to extend the use of OprI vectors in other Gram (-) bacteria, resulting in the production of outer membrane-bound lipid-modified molecules, opening the possibility for its application in the design of potential live Salmonella-based subunit vaccines.

Scientific publication productivity of Libyan medical schools: a bibliometric study of papers listed in PubMed, 1988-2007

BACKGROUND

Scientific publication is a vital mission of medical schools and it is important to periodically document how well schools fulfil this mission.

AIMS

This study aimed to analyse the publication record of Libyan medical schools in international journals indexed in PubMed between 1988 and 2007.

METHODS

Medline was searched using PubMed for publications affiliated to Libya during 1988-2007.

RESULTS

Out of 417 papers related to Libya, 348 (84%) are affiliated to the medical schools and related hospitals. More than 60% of the 348 papers are affiliated to Al-Arab Medical University, Benghazi, while Al-Fateh Medical University, Tripoli, contributed 103 papers (30%). The rest of the papers (n=25, 7%) were published by medical schools in other parts of the country. The publication rate declined by 3% annually between 1988 and 2007. The decline was mainly due to a decrease in the publication rate by Al-Arab Medical University, Benghazi. Overall, nine departments produced 10 or more papers each. Out of about 1675 staff members, there are only 148 first authors and 207 last authors. The estimated annual publication rate is 0.7 papers per 100 academic staff members.

CONCLUSION

This study reveals that published scholarship of the Libyan medical schools is extremely low, that the publication rate has declined, and that most academic staff have no publications listed in PubMed. This issue needs urgent attention.