Rapid clonal analysis of recurrent tuberculosis by direct MIRU-VNTR typing on stored isolates

Background  

The application of molecular tools to the analysis of tuberculosis has revealed examples of clonal complexity, such as exogenous reinfection, coinfection, microevolution or compartmentalization. The detection of clonal heterogeneity by standard genotyping approaches is laborious and often requires expertise. This restricts the rapid availability of Mycobacterium tuberculosis (MTB) genotypes for clinical or therapeutic decision-making. A new PCR-based technique, MIRU-VNTR, has made it possible to genotype MTB in a time frame close to real-time fingerprinting. Our purpose was to evaluate the capacity of this technique to provide clinicians with a rapid discrimination between reactivation and exogenous reinfection and whether MIRU-VNTR makes it possible to obtain data directly from stored MTB isolates from recurrent episodes.     

Altering coenzyme specificity of <Emphasis Type="Italic">Pichia stipitis</Emphasis> xylose reductase by the semi-rational approach CASTing

Background  

The NAD(P)H-dependent Pichia stipitis xylose reductase (PsXR) is one of the key enzymes for xylose fermentation, and has been cloned into the commonly used ethanol-producing yeast Saccharomyces cerevisiae. In order to eliminate the redox imbalance resulting from the preference of this enzyme toward NADPH, efforts have been made to alter the coenzyme specificity of PsXR by site-directed mutagenesis, with limited success. Given the industrial importance of PsXR, it is of interest to investigate further ways to create mutants of PsXR that prefers NADH rather than NADPH, by the alternative directed evolution approach.     

Evolutionary conservation of plant gibberellin signalling pathway components

Background:  

Gibberellins (GA) are plant hormones that can regulate germination, elongation growth, and sex determination. They ubiquitously occur in seed plants. The discovery of gibberellin receptors, together with advances in understanding the function of key components of GA signalling in Arabidopsis and rice, reveal a fairly short GA signal transduction route. The pathway essentially consists of GID1 gibberellin receptors that interact with F-box proteins, which in turn regulate degradation of downstream DELLA proteins, suppressors of GA-controlled responses.     

A role for Insulin-like growth factor 2 in specification of the fast skeletal muscle fibre

Background  

Fibre type specification is a poorly understood process beginning in embryogenesis in which skeletal muscle myotubes switch myosin-type to establish fast, slow and mixed fibre muscle groups with distinct function. Growth factors are required to establish slow fibres; it is unknown how fast twitch fibres are specified. Igf-2 is an embryonically expressed growth factor with established in vitro roles in skeletal muscle. Its localisation and role in embryonic muscle differentiation had not been established.     

Germline mutagenesis mediated by <Emphasis Type="Italic">Sleeping Beauty</Emphasis>transposon system in mice

Following the descovery of its transposition activity in mammalian culture systems, the Sleeping Beauty (SB) transposon has since been applied to achieve germline mutagenesis in mice. Initially, the transposition efficiency was found to be low in cultured systems, but its activity in germ cells was unexpectedly high. This difference in transposition efficiency was found to be largely dependent on chromosomal status of the host genomic DNA and transposon vector design. The SB transposon system has been found to be suitable for comprehensive mutagenesis in mice. Therefore, it is an effective tool as a forward genetics screen for tagged insertional mutagenesis in mice.     

Vasculitis: mechanisms involved and clinical manifestations

Systemic vasculitis, an inflammatory necrotizing disease of the blood vessel walls, can occur secondary to autoimmune diseases, including connective tissue diseases. Various pathogenic mechanisms have been implicated in the induction of vasculitis, including cell-mediated inflammation, immune complex-mediated inflammation and autoantibody-mediated inflammation. This inflammatory activity is believed to contribute to accelerated atherosclerosis, and also leads to increased risk for cardiovascular events in patients with rheumatoid arthritis and systemic lupus erythematosus. Endothelial cell activation is a common pathogenic pathway in the systemic vasculitis associated with rheumatoid arthritis and systemic lupus erythematosus, with elevated levels of endothelin-1 potentially inducing vascular dysregulation.     

Cloning,characterization, and mutational analysis of a highly active and stable <Emphasis Type="SmallCaps">l</Emphasis>-arabinitol 4-dehydrogenase from <Emphasis Type="Italic">Neurospora crassa</Emphasis>

An NAD⁺-dependent l-arabinitol 4-dehydrogenase (LAD, EC 1.1.1.12) from Neurospora crassa was cloned and expressed in Escherichia coli and purified to homogeneity. The enzyme was a homotetramer and contained two Zn²⁺ ions per subunit, displaying similar characteristics to medium-chain sorbitol dehydrogenases (SDHs). High enzymatic activity was observed for substrates l-arabinitol, adonitol, and xylitol and no activity for d-mannitol, d-arabinitol, or d-sorbitol. The enzyme showed strong preference for NAD⁺ but also displayed a very low yet detectable activity with NADP⁺. Mutational analysis of residue F59, the single different substrate-binding residue between LADs and d-SDHs, failed to confer the enzyme the ability to accept d-sorbitol as a substrate, suggesting that the amino acids flanking the active site cleft may be responsible for the different activity and affinity patterns between LADs and SDHs. This enzyme should be useful for in vivo and in vitro production of xylitol and ethanol from l-arabinose. Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Effect of plant structure on oviposition behavior of Anopheles minimus s.l.

Knowledge of factors that influence oviposition behavior of malaria mosquitoes is critical to vector control measures aimed at larval habitat modifications and source reduction. Anopheles minimus s.l., an important malaria vector in Southeast Asia, generally breeds in clear, unpolluted water along shaded grassy edges of slow-moving streams. The objective of this study was to determine the influence of vegetation and plant structure on An. minimus s.l. ovipositing females. Twenty gravid female mosquitoes per replication were given a choice to lay eggs in bowls surrounded by different combinations of bare soil, grasses, small-leaved plants, and large-leaved plants. An. minimus s.l. females generally preferred to lay eggs in bowls with vegetation. A significantly higher number of eggs were found in bowls with small-leaved plants compared to bowls with grasses (P<0.05). The results suggest that gravid females preferred oviposition habitats in the following order: small-leaved plants > large-leaved plants > grasses > soil. Further studies are needed to determine the possible roles of plant structure and factors such as semiochemicals in the different species of the An. minimus species complex. Knowledge of female oviposition behavior is essential for the development of locally adapted vector control approaches.