Comparative analysis of cyanobacterial superoxide dismutases to discriminate canonical forms

<p>Abstract</p> <p>Background</p> <p>Superoxide dismutases (SOD) are ubiquitous metalloenzymes that catalyze the disproportion of superoxide to peroxide and molecular oxygen through alternate oxidation and reduction of their metal ions. In general, SODs are classified into four forms by their catalytic metals namely; FeSOD, MnSOD, Cu/ZnSOD and NiSOD. In addition, a cambialistic form that uses Fe/Mn in its active site also exists. Cyanobacteria, the oxygen evolving photosynthetic prokaryotes, produce reactive oxygen species that can damage cellular components leading to cell death. Thus, the co-evolution of an antioxidant system was necessary for the survival of photosynthetic organisms with SOD as the initial enzyme evolved to alleviate the toxic effect. Cyanobacteria represent the first oxygenic photoautotrophs and their SOD sequences available in the databases lack clear annotation. Hence, the present study focuses on structure and sequence pattern of subsets of cyanobacterial superoxide dismutases.</p> <p>Result</p> <p>The sequence conservation and structural analysis of Fe (<it>Thermosynechococcus elongatus </it>BP1) and MnSOD (<it>Anabaena </it>sp. PCC7120) reveal the sharing of N and C terminal domains. At the C terminal domain, the metal binding motif in cyanoprokaryotes is DVWEHAYY while it is D-X-[WF]-E-H-[STA]-[FY]-[FY] in other pro- and eukaryotes. The cyanobacterial FeSOD differs from MnSOD at least in three ways <it>viz</it>. (i) FeSOD has a metal specific signature F184X₃A188Q189_.......T280_......F/Y303 while, in Mn it is R184X₃G188G189_......G280......W303, (ii) aspartate ligand forms a hydrogen bond from the active site with the outer sphere residue of W243 in Fe where as it is Q262 in MnSOD; and (iii) two unique lysine residues at positions 201 and 255 with a photosynthetic role, found only in FeSOD. Further, most of the cyanobacterial Mn metalloforms have a specific transmembrane hydrophobic pocket that distinguishes FeSOD from Mn isoform. Cyanobacterial Cu/ZnSOD has a copper domain and two different signatures G-F-H-[ILV]-H-x-[NGT]-[GPDA]-[SQK]-C and G-[GA]-G-G-[AEG]-R-[FIL]-[AG]-C-G, while Ni isoform has an nickel containing SOD domain containing a Ni-hook HCDGPCVYDPA.</p> <p>Conclusion</p> <p>The present analysis unravels the ambiguity among cyanobacterial SOD isoforms. NiSOD is the only SOD found in lower forms; whereas, Fe and Mn occupy the higher orders of cyanobacteria. In conclusion, cyanobacteria harbor either Ni alone or a combination of Fe and Ni or Fe and Mn as their catalytic active metal while Cu/Zn is rare.</p

Impacts and intricacies of mass quarantine on Covid-19 and possible role of artificial intelligence (AI) in mitigation

Ongoing Covid-19 is a new global threat with a devastating impact on lives and economy especially in China, the origination spot of epidemic. The catastrophic nature of an epidemic depends on isolation and quarantine measures. The impact of mass quarantine in China in containing Covid -19 has been discussed. Repercussions of mass quarantine and its profound adverse concerns on healthy individuals and economy has been presented. Role of artificial intelligence in early warning alert and its impacts are discussed. In conclusion, the ability to recognize outbreaks and act is still challenging as each event is unique in its own way. In other words, the causative organisms are smarter than human and human made algorithms. Nevertheless, the expensive lessons learnt enable us to prepare ourselves to prevent such disasters which is an on-going battle

Investigation of extraneous peak reveals ethylene oxide in food supplements

The global food supplement market is growing rapidly and so as the concerns on their quality, safety, and product efficacy. Product monitoring is challenging due to lenient regulation across the globe when compared to pharmaceutical counterparts. As part of quality and safety compliance of food supplements, products are being tested randomly in the Emirate of Abu Dhabi, UAE. This study is the part of routine monitoring of supplements during which an extraneous peak was observed and characterized. Analysis was performed using a Gas chromatography coupled to mass spectrometry and headspace extraction sampler. The extraneous peak with signal to noise ratio (S/N) of 140 was identified as ethylene oxide. Since traces were observed in active product formulation, it is worthwhile to monitor the levels in a higher number of supplements to elucidate its significance

Would edible insects become part of our gastronomic quest?

Global food security status has been contested in recent times with claims of efficient food production by the proponents and severe to moderate food insecurity by the opponents. The current population growth prediction of 9.7 billion by 2050 requires additional food production due to the impact of climate change leading to diminished yield rates. Novel food sources such as cellular agriculture utilizing modern biotechnology are at various trial and commercialization stages. Old traditions of insects as a reliable food (entomophagy) source are gaining momentum in recent times. This article explores various aspects of entomophagy. The ecological footprint of entomophagy on its animal counterparts is presented. Since religious factors have a major impact on eating habits that privileges certain elements, perspectives from major religions on entomophagy have been discussed. The regulatory standpoint of Anglo-Saxon, Western and Eastern societies are given. Consumer knowledge and commercialization challenges are also discussed with concluding remarks

Molecular characterization of marine cyanobacteria from the Indian subcontinent deduced from sequence analysis of the phycocyanin operon (cpcB-IGS-cpcA) and 16S-23S ITS region

Molecular characterization of ten marine cyanobacterial isolates belonging to the order Oscillatoriales was carried out using the phycocyanin locus (cpcBA-IGS) and the 16S-23S internally transcribed spacer region. DNA sequences from the phycocyanin operon discriminated ten genotypes, which corresponded to seven morphotypes identified by traditional microscopic analysis. The cpcB coding region revealed 17% nucleotide variation, while cpcA exhibited 29% variation across the studied species. Phylogenetic analyses support the conclusion that the Phormidium and Leptolyngbya genera are not monophyletic. The nucleotide variations were heterogeneously distributed with no or minimal informative nucleotides. Our results suggest that the discriminatory power of the phycocyanin region varies across the cyanobacterial species and strains. The DNA sequence analysis of the 16S-23S internally transcribed spacer region also supports the polyphyletic nature of the studied oscillatorian cyanobacteria. This study demonstrated that morphologically very similar strains might differ genotypically. Thus, molecular approaches comprising different gene regions in combination with morphological criteria may provide better taxonomical resolution of the order Oscillatoriales