Low-temperature complete combustion of a dilute mixture of methane and propane over transition-metal-doped ZrO2 catalysts: effect of the presence of propane on methane combustion.

Complete combustion of dilute methane alone or a dilute mixture of methane and propane over transition-metal (viz. Mn, Co, Cr, Fe, and Ni)-doped ZrO2 (cubic) catalysts at different temperatures (523-873 K) and a space velocity of 51,000 cm3 x g(-1) x h(-1) has been investigated for controlling methane and propane emissions from exhaust gases. The catalysts are compared for their catalytic ignition temperature and activity in the combustion of propane and methane in the presence of each other.

Intramolecular i-motif structure at acidic pH for progressive myoclonus epilepsy (EPM1) repeat d(CCCCGCCCCGCG)n.

The most common mutation associated with Progressive Myoclonus Epilepsy (EPM1) of Unverricht-Lundberg type is the expansion of a dodecamer repeat, d(CCCCGCCCCGCG)n. We show that the C-rich strand of this repeat (2-3 copies) forms intercalated i-motif structure at acidic pH as judged by CD spectroscopy and anomalous gel electrophoretic mobility. The stability of the structure increases with the increase in the length of the repeat.

Progressive myoclonus epilepsy [EPM1] repeat d(CCCCGCCCCGCG)n forms folded hairpin structures at physiological pH.

The secondary structure of DNA has been shown to be an important component in the mechanism of expansion of the trinucleotide repeats that are associated with many neurodegenerative disorders. Recently, expansion of a dodecamer repeat, (CCCCGCCCCGCG)n upstream of cystatin B gene has been shown to be the most common mutation associated with Progressive Myoclonus Epilepsy (EPM1) of Unverricht-Lundborg type. We have investigated structure of oligonucleotides containing one, two and three copies of the EPM1 repeat sequences at physiological pH.

Simple repetitive sequences in the genome: structure and functional significance.

The current explosion of DNA sequence information has generated increasing evidence for the claim that noncoding repetitive DNA sequences present within and around different genes could play an important role in genetic control processes, although the precise role and mechanism by which these sequences function are poorly understood. Several of the simple repetitive sequences which occur in a large number of loci throughout the human and other eukaryotic genomes satisfy the sequence criteria for forming non-B DNA structures in vitro. We have summarized some of the features of three different types of simple repeats that highlight the importance of repetitive DNA in the control of gene expression and chromatin organization.