Observational study of fetomaternal outcome in pregnancy with COVID-19 infection

Background: According to World Health Organization (WHO) COVID-19 is declared as an infection of international health emergency on 11 March 2020. It is not clear whether clinical characteristics of pregnant women with COVID-19 infection differ from those of non-pregnant women and whether it aggravates its symptoms.Methods: This is a prospective observational study of 75 cases based on compiled clinical data of pregnant women with COVID-19 infection admitted to Hi-Tech Medical College from June 2020 to July 2021. All laboratory confirmed positive cases were included.Results: The most common symptoms reported was fever (24%) followed by myalgia, cough and shortness of breath, while 60% patients were asymptomatic. there were total 57 deliveries, out of which 46 were live birth. The incidence of preterm birth was 26.3%. Maternal mortality was maximum between 25-34 weeks of GA. 96.9% of new-born were tested for SARS CoV-2 and only 10 were found to be positive (17.5%).Conclusions: At present there is no evidence regarding increased risk of pregnant women succumbed to COVID-19 infection and experience severe pneumonia. The risk of preterm birth and spontaneous abortion not increased as reported in this study but shows possibilities of vertical transmission. COVID-19 infection in pregnancy with or without any comorbidities can cause complication to both mother and fetus irrespective of treatment. We aim to evaluate the association between SARS CoV-2 infection during pregnancy and adverse pregnancy outcomes

Fe2+ substrate transport through ferritin protein cage ion channels influences enzyme activity and biomineralization

Ferritins, complex protein nanocages, form internal iron-oxy minerals (Fe2O3·H2O), by moving cytoplasmic Fe(2+) through intracage ion channels to cage-embedded enzyme (2Fe(2+)/O2 oxidoreductase) sites where ferritin biomineralization is initiated. The products of ferritin enzyme activity are diferric oxy complexes that are mineral precursors. Conserved, carboxylate amino acid side chains of D127 from each of three cage subunits project into ferritin ion channels near the interior ion channel exits and, thus, could direct Fe(2+) movement to the internal enzyme sites. Ferritin D127E was designed and analyzed to probe properties of ion channel size and carboxylate crowding near the internal ion channel opening. Glu side chains are chemically equivalent to, but longer by one -CH2 than Asp, side chains. Ferritin D127E assembled into normal protein cages, but diferric peroxo formation (enzyme activity) was not observed, when measured at 650 nm (DFP λ max). The caged biomineral formation, measured at 350 nm in the middle of the broad, nonspecific Fe(3+)-O absorption band, was slower. Structural differences (protein X-ray crystallography), between ion channels in wild type and ferritin D127E, which correlate with the inhibition of ferritin D127E enzyme activity include: (1) narrower interior ion channel openings/pores; (2) increased numbers of ion channel protein-metal binding sites, and (3) a change in ion channel electrostatics due to carboxylate crowding. The contributions of ion channel size and structure to ferritin activity reflect metal ion transport in ion channels are precisely regulated both in ferritin protein nanocages and membranes of living cells

Phenothiazines and phenoxazines: as electron transfer mediators for ferritin iron release

Intracellular ferritin stores iron as ferrihydrite and releases it for various cellular metabolic activities. The reductive approach, one of the possible mechanisms of iron mobilization from ferritin nanocages, requires electron transfer (ET) from reducing agent(s) to the protein encapsulated iron. In vitro, the rate of ET from the physiological reducing agent, NADH, to mineralized ferritin is very slow resulting in a smaller amount of iron release. Therefore, medically relevant phenothiazine (TH/MB/MG/TDB) and phenoxazine (BCB/CRV/NB) dyes were used as ET mediators to facilitate the electron relay and to evaluate their iron releasing ability from ferritin. These dyes have earlier been exploited as ET mediators during electrocatalysis and in the treatment of methemoglobinemia. With the exception of MG, the midpoint potentials (E-1/2) and NADH oxidizing abilities of these dyes dictated by their structure and the reaction conditions along with the dye-ferritin interaction govern the kinetics of reductive iron mobilization. A greater amount of iron release was observed in the case of TH, BCB and CRV. In comparison to neutral pH, acidic pH altered E-1/2 and protein conformation leading to enhanced iron mobilization, whereas dissolved O-2 and the photosensitizing effect of dyes were found to have a negligible impact. In analogy to in vitro, the acidic environment of the lysosome may bring about similar changes in the reducing agents/dye mediators/ferritin to facilitate the iron release process in vivo. Following Marcus theory, our current observations suggest that the dyes with E-1/2 values well separated from those of the reducing agents and ferritin's mineral core can be exploited to facilitate iron release during iron overload conditions

Spectroscopic Studies of Single and Double Variants of M Ferritin: Lack of Conversion of a Biferrous Substrate Site into a Cofactor Site for O₂ Activation

Ferritin has a binuclear non-heme iron active site that functions to oxidize iron as a substrate for formation of an iron mineral core. Other enzymes of this class have tightly bound diiron cofactor sites that activate O₂ to react with substrate. Ferritin has an active site ligand set with 1-His/4-carboxylate/1-Gln rather than the 2-His/4-carboxylate set of the cofactor site. This ligand variation has been thought to make a major contribution to this biferrous substrate rather than cofactor site reactivity. However, the Q137E/D140H double variant of M ferritin, has a ligand set that is equivalent to most of the diiron cofactor sites, yet did not rapidly react with O₂ or generate the peroxy intermediate observed in the cofactor sites. Therefore, in this study, a combined spectroscopic methodology of circular dichroism (CD)/magnetic CD (MCD)/variable temperature, variable field (VTVH) MCD has been applied to evaluate the factors required for the rapid O₂ activation observed in cofactor sites. This methodology defines the coordination environment of each iron and the bridging ligation of the biferrous active sites in the double and corresponding single variants of frog M ferritin. Based on spectral changes, the D140H single variant has the new His ligand binding, and the Q137E variant has the new carboxylate forming a μ-1,3 bridge. The spectra for the Q137E/D140H double variant, which has the cofactor ligand set, however, reflects a site that is more coordinately saturated than the cofactor sites in other enzymes including ribonucleotide reductase, indicating the presence of additional water ligation. Correlation of this double variant and the cofactor sites to their O₂ reactivities indicates that electrostatic and steric changes in the active site and, in particular, the hydrophobic nature of a cofactor site associated with its second sphere protein environment, make important contributions to the activation of O₂ by the binuclear non-heme iron enzymes

New vegetation type map of India prepared using satellite remote sensing: Comparison with global vegetation maps and utilities

International audienceA seamless vegetation type map of India (scale 1: 50,000) prepared using medium-resolution IRS LISS-III images is presented. The map was created using an on-screen visual interpretation technique and has an accuracy of 90%, as assessed using 15,565 ground control points. India has hitherto been using potential vegetation/forest type map prepared by Champion and Seth in 1968. We characterized and mapped further the vegetation type distribution in the country in terms of occurrence and distribution, area occupancy, percentage of protected area (PA) covered by each vegetation type, range of elevation, mean annual temperature and precipitation over the past 100 years. A remote sensing-amenable hierarchical classification scheme that accommodates natural and semi-natural systems was conceptualized, and the natural vegetation was classified into forests, scrub/shrub lands and grasslands on the basis of extent of vegetation cover. We discuss the distribution and potential utility of the vegetation type map in a broad range of ecological, climatic and conservation applications from global, national and local perspectives. We used 15,565 ground control points to assess the accuracy of products available globally (i.e., GlobCover, Holdridge’s life zone map and potential natural vegetation (PNV) maps). Hence we recommend that the map prepared herein be used widely. This vegetation type map is the most comprehensive one developed for India so far. It was prepared using 23.5 m seasonal satellite remote sensing data, field samples and information relating to the biogeography, climate and soil. The digital map is now available through a web portal (http://bis.iirs.gov.in)