Cardamom Derived Phytochemicals against Mycobacterium tuberculosis Causing Tuberculosis

Tuberculosis is a disease caused by severe infections by Mycobacterium tuberculosis, a pathogenic bacteria. These bacteria cause infections in humans and thus lead to an unhealthy life. Phytochemicals from cardamom plant extract are traditionally used to cure Tuberculosis. Molecular docking method applied using “Biovia Discovery Studio”. “High positive values of -CDOCKER energy and -CDOCKER interaction energy” suggested that acetic acid can effectively deactivate histidinol dehydrogenase (H37Rv) thereby interrupting the life cycle of the organism.

Mycobacterium tuberculosis histidinol dehydrogenase: biochemical characterization and inhibition studies

We describe a series of biochemical studies on recombinantMycobacterium tuberculosisHisD (MtHisD) and the synthesis of a series of compounds which are, to the best of our knowledge, the first inhibitors ofMtHisD activity reported in the literature.

Increased expression and secretion of recombinant hIFNγ through amino acid starvation-induced selective pressure on the adjacent HIS4 gene in Pichia pastoris

Transcriptional co-regulation of adjacent genes has been observed for prokaryotic and eukaryotic organisms, alike. High levels of gene adjacency were also found in a wide variety of yeast species with a high frequency of co-regulated gene sets. The aim of this research was to study how selective pressure on the Histidinol dehydrogenase gene (HIS4), using amino acid starvation, affects the level of expression and secretion of the adjacent human interferon gamma gene (hIFNγ) in the recombinant Pichia pastoris GS115 strain, a histidine-deficient mutant. hIFNγ was cloned into the pPIC9 vector adjacent to the HIS4 gene, a gene essential for histidine biosynthesis, which was then transformed into P. pastoris. The transformed P. pastoris was cultured under continuous amino acid starvation in amino acid-free minimal medium for ten days, with five inoculations into unspent medium every second day. Under these conditions, only successfully transformed cells (hIFNγ -HIS4+) are able to synthesise histidine and therefore thrive. As shown by ELISA, amino acid starvation-induced selective pressure on HIS4 improved expression and secretion of the adjacent hIFNγ by 55% compared to unchallenged cells. RT-qPCR showed that there was also a positive correlation between duration of amino acid starvation and increased levels of the hIFNγ RNA transcripts. According to these results, it is suggested that these adjacent genes (hIFNγ and HIS4) in the transformed P. pastoris are transcriptionally co-regulated and their expression is synchronised. To the best of the knowledge of the authors; this is the first study demonstrating that amino acid starvationinduced selective pressure on HIS4 can alter the regulation pattern of adjacent genes in P. pastoris.

Exploiting a Natural Auxotrophy for Genetic Selection

ABSTRACTWe exploited the natural histidine auxotrophy ofFrancisellaspecies to develophisD(encodes histidinol dehydrogenase) as a positive selection marker. A shuttle plasmid (pBR103) carryingEscherichia coli hisDand designed for cloning of PCR fragments replicated in both attenuated and highly virulentFrancisellastrains. During this work, we formulated a simplified defined growth medium forFrancisella novicida.