Recent news

Wits node researchers achieve breakthrough in study on the resuscitation-promoting factors of Mycobacterium tuberculosis
Researchers in the Wits node of the CBTBR have achieved a breakthrough in understanding the physiological role of the resuscitation-promoting factors (Rpfs) of M. tuberculosis. The five Rpfs in this organism, RpfA-E, are implicated in resuscitation of this organism from dormancy via a mechanism involving hydrolysis of the peptidoglycan by Rpfs and partnering proteins. In the new study, led by CBTBR Team Members Bavesh Kana and Bhavna Gordhan, the rpfA-E genes were shown to be collectively dispensable for growth of M. tuberculosis in broth culture. This work involved the construction of a large set of mutant strains of M. tuberculosis carrying up to five unmarked deletion mutations, which represents a technical achievement unmatched in this field. The defect in resuscitation of multiple mutants from a ‘non-culturable’ state induced by starvation under conditions of oxygen restriction was reversed by genetic complementation or addition of culture filtrate from wild type organisms confirming that this phenotype was associated with rpf-like gene loss. Other phenotypes uncovered by sequential deletion mutagenesis revealed a functional differentiation within this protein family. The quintuple mutant and its parent that retained only rpfD displayed delayed colony formation and hypersensitivity to detergent, effects not observed for mutants retaining only rpfE or rpfB. Furthermore, mutants retaining rpfD or rpfE were highly attenuated for growth in mice with the latter persisting better than the former in late-stage infection. In conjunction, these results are indicative of a hierarchy in terms of function and/or potency with the Rpf family, with RpfB and RpfE ranking above RpfD.

This study was a close collaborative effort with the laboratories of Gilla Kaplan from the Public Health Research Institute in New Jersey, Arseny Kaprelyants from the Russian Academy of Sciences in Moscow, and Mike Young from Aberystwyth University in Wales and was published in the January 2008 issue of Molecular Microbiology.
For access to this article, which is available online for free, click on the link below: http://www.blackwell-synergy.com/doi/abs/10.1111/j.1365-2958.2007.06078.x

CBTBR boasts a whopping 9 PhD graduates in 2007/8
The CBTBR has successfully produced 9 PhD graduates in the past year. These students with their “thesis titles” are as follows: Teri Roberts (The characterization of immune responses during Mycobacterium tuberculosis infection), Hanne Veenstra (The Investigation Of Peripheral Blood Cellular Immune Responses During Infection With Mycobacterium Tuberculosis), Elizabeth M. Streicher (Application of spoligotyping in the understanding of the dynamics of Mycobacterium tuberculosis strains in high incidence communities), Chantal Louiza Babb (Identification of candidate genes and testing for association with tuberculosis in humans), Marlo Möller (Human genetic susceptibility to tuberculosis: The investigation of candidate genes influencing interferon gamma levels and other candidate genes affecting immunological pathways), Hendrik Johannes Nel (The influence of helminth infection on the host immune response to mycobacteria), Don Hayward (Functional and genetic study of M.tuberculosis Glutamine Synthetase (GS) and other factors possibly involved in GS metabolism), Rabia Johnson (Understanding the mechanisms of drug resistance in enhancing rapid molecular detection of drug resistance in Mycobacterium tuberculosis) and Joel Fleury Djoba Siawaya (Immune Parameters as Biomarkers of Mycobacterium tuberculosis Sterilization during Anti-tuberculosis Treatment).

In Photo: Some of the CBTBR PhD graduates and their supervisors at the Awards Ceremony.

Co-Director of CBTBR appointed to Council of Scientific Advisors of the ICGEB
Valerie Mizrahi has been elected to the Council of Scientific Advisors of the International Centre for Genetic Engineering and Biotechnology (ICGEB), which advises the Board of the ICGEB. Her appointment to this Council commenced in January, 2008.

The ICGEB conducts innovative research in life sciences for the benefit of developing countries. It strengthens the research capability of its Members through training and funding programmes and advisory services and represents a comprehensive approach to promoting biotechnology internationally. The Centre is dedicated to advanced research and training in molecular biology and biotechnology and holds out the prospect of advancing knowledge and applying the latest techniques in the fields of biomedicine; crop improvement; environmental protection/remediation; biopharmaceuticals and biopesticide production.

The ICGEB provides a scientific and educational environment of the highest standard. It brings biotechnology to developing countries by strengthening their research capabilities, developing state-of-the-art research and training scientists to the benefit of its Member States. The ICGEB recently established a Component in Africa, which is located at the University of Cape Town. For further information, go to http://www.icgeb.trieste.it/RESEARCH/CapeTown.htm.