A Group I Self-Splicing Intron in the Flagellin Gene of the Thermophilic Bacterium Geobacillus stearothermophilus

A group I intron that can be spliced in vivo and in vitro was identified in the flagellin gene of the thermophilic bacterium Geobacillus stearothermophilus. We also found one or two intervening sequences (IVS) of flagellin genes in five additional bacterial species. Furthermore, we report the presence of these sequences in two sites of a highly conserved region in the flagellin gene.     

Cytotoxic diterpenes from roots of Crossopetalum gaumeri,a Celastraceae species from Yucatan Peninsula

Four new diterpenes, crossogumerins A–D (1–4) along with six known ones (5–10) were isolated from the root bark of Crossopetalum gaumeri, an endemic medicinal plant from the Yucatan Peninsula. Their structures were elucidated on the basis of 1D and 2D NMR techniques, including HMQC, HMBC, and ROESY experiments. Compounds 1–5, 8–10 were evaluated for cytotoxicity against HeLa (carcinoma of the cervix) and Hep-2 (lung carcinoma) human tumor cells lines and against normal Vero cells (African green monkey kidney) in lag and log phase of growth. Podocarpane diterpenes, crossogumerin B (2) and nimbiol (10), exhibited the highest activity against HeLa cells (IC₅₀ values of 3.1 and 8.1 μM, respectively), but also selectivity on Vero cells (SI 22.6 and 7.5, respectively). The preliminary SAR studies suggest that an epoxy moiety in ring B and a hydrogen bond-donor group strategically positioned in the diterpene core are important requirements for cytotoxicity and selectivity.     

Cloning of the cellulase gene from Penicillium funiculosum and its expression in Escherichia coli

A gene of Penicillium funiculosum encoding an endoglucanase was cloned and expressed in Escherichia coli using the lacZ promoter of vector pUC 18. The gene product hydrolyzed carboxymethyl cellulose and showed strong cross reactivity with P. funiculosum anticellulases.