A good standard reference for the highly polymorphic human mitochondrial DNA (mtDNA) sequence is essential for studies of normal and disease-related nucleotide variants in the mitochondrial genome. A consensus sequence for the human mitochondrial genome has been derived from thirteen unrelated mtDNA sequences. We report 128 nucleotide variants of the human mtDNA sequence, and 62 amino acid variants of the human mitochondrial translation products, observed in the coding region of these mtDNA sequences.

Aims: The aims were to isolate a raw starch-degrading a-amylase gene baqA from Bacillus aquimaris MKSC 6.2, and to characterize the gene product through in silico study and its expression in Escherichia coli. Methods and Results:A 1539 complete open reading frame of a starchdegrading a-amylase gene baqA from B. aquimaris MKSC 6Á2 has been determined by employing PCR and inverse PCR techniques. Bioinformatics analysis revealed that B. aquimaris MKSC 6.2 a-amylase (BaqA) has no starchbinding domain, and together with a few putative a-amylases from bacilli may establish a novel GH13 subfamily most closely related to GH13_1. Two consecutive tryptophans (Trp201 and Trp202, BaqA numbering) were identified as a sequence fingerprint of this novel GH13 subfamily. Escherichia coli cells produced the recombinant BaqA protein as inclusion bodies. The refolded recombinant BaqA protein degraded raw cassava and corn starches, but exhibited no activity with soluble starch. Conclusions: A novel raw starch-degrading B. aquimaris MKSC 6.2 a-amylase BaqA is proposed to be a member of new GH13 subfamily. Significance and Impact of the Study: This study has contributed to the overall knowledge and understanding of amylolytic enzymes that are able to bind and digest raw starch directly.

Intergenomic variation in the human mitochondrial genome was examined in 27 mtDNA sequences using a pairwise analysis technique. Analysis of 16 of these mtDNA sequences from patients with mitochondrial cytopathies indicated a wide range between different mitochondrial genes in the degree of nucleotide variation from the standard Cambridge sequence. Mean complex I polymorphic frequencies in cytopathic (CPEO, MERRF, MELAS and LHON collectively) patients and in LHON patients differed significantly from controls (P < or = 0.05, t). Total mean sequence divergence (mean number of diverging nucleotides between two sequences per 100 bp) over the entire mtDNA coding region was 0.21% for cytopathies (n = 16) as opposed to 0.18% for a control group (n = 4). Within the cytopathy group, the greatest pairwise divergence was observed in ND3 and ND6 subunits of complex I (0.46 and 0.70% respectively) and the magnitude of specific gene divergences differed considerably from those observed for the corresponding genes in the control population. The extent to which the increased variation in ND3 and ND6 is a general phenomenon applicable to all subjects rather than a finding specific to cytopathies cannot be stated with certainty given the small control group. Regardless as to which of these suggestions is correct, the possibility exists that increased nucleotide variation in certain mitochondrial ND subunits may contribute to respiratory inefficiency through a cumulative effect of a series of polymorphisms of minor individual mutagenic potential.

Most of isoniazid-resistant Mycobacterium tuberculosis evolved due to mutation in the katG gene encoding catalase-peroxidase. A set of new mutations, namely T1310C, G1388T, G1481A, T1553C, and A1660G, which correspond to amino acid substitutions of L437P, R463L, G494D, I518T, and K554E, in the katG gene of the L10 clinical isolate M. tuberculosis was identified. The wild-type and mutant KatG proteins were expressed in Escherichia coli BL21(DE3) as a protein of 80 kDa based on sodium dodecyl sulphate-polyacrylamide gel electrophoresis analysis. The mutant KatG protein exhibited catalase and peroxidase activities of 4.6% and 24.8% toward its wild type, respectively, and retained 19.4% isoniazid oxidation activity. The structure modelling study revealed that these C-terminal mutations might have induced formation of a new turn, perturbing the active site environment and also generated new intramolecular interactions, which could be unfavourable for the enzyme activities.

Partially purified α‐amylase from Bacillus aquimaris MKSC 6.2, a bacterium isolated from a soft coral Sinularia sp., Merak Kecil Island, West Java, Indonesia, showed an ability to degrade raw corn, rice, sago, cassava, and potato starches with adsorption percentage in the range of 65–93%. Corn has the highest degree of hydrolysis followed by cassaca, sago potato and rice, consecutively. The end products of starch hydrolysis were a mixture of maltose, maltotriose, maltotetraose, maltopentaose, maltohexaose, and small amount of glucose.