Stretching of a single-stranded DNA: Evidence for structural transition

Recent experiments have shown that the force-extension (F-x) curve for single-stranded DNA (ssDNA) consisting only of adenine [poly(dA)] is significantly different from thymine [poly(dT)]. Here, we show that the base stacking interaction is not sufficient to describe the F-x curves as seen in the experiments. A reduction in the reaction co-ordinate arising from the formation of helix at low forces and an increase in the distance between consecutive phosphates of unstacked bases in the stretched state at high force in the proposed model, qualitatively reproduces the experimentally observed features. The multi-step plateau in the F-x curve is a signature of structural change in ssDNA.Comment: 10 pages, 4 figure

Seasonal Fluctuations in Quality of Water from Gandak River

During present investigation, water samples were collected from GANDAK RIVER during June 2016 to July2017and analyzed the same by examining various parameters like pH, Temperature, Turbidity, Dissolved oxygen, Free CO2, Alkalinity, Chloride etc. The temperature, turbidity were determined using thermometer, Sacchi disc, Ruttner’s Barrier layer Photocells respectively. The pH, dissolved oxygen, free CO2 & alkalinity, Chloride and nitrogen were analyzed following Kodarkar(1992).. Keywords: water, seasonal fluctuations, Zooplanktons

Insecticidal effects of aqueous extracts of wild pomegranate peel and seed (Punica granatum L.) against rose aphids, Macrosiphum rosaeformis

Efficacy of wild pomegranate (Punica granatum Linn.) fruit peel and seeds aqueous extract was evaluated for the control of common insect pests aphids (Macrosiphum rosaeformis) and for its influence on useful non-target predators viz., Coccinella septempunctata. Lethal doses of daru peel and seed suggested these became more toxic to aphids after 24 hr of exposure. A significant difference was obtained in percentage aphids reached to untreated leaves over peel extract treated leaves (23:57 and 23:77) and seed extract treated leaves (7:80 and 17:80) at 90 and 180 min time intervals in food choice assays. No significant effect was observed against Coccinella. LC50 values of daru peel and seed extracts along with mixture of three flavonoids (Kaempferol, Quercetin and Myricetin) were assessed at 48 hr values were 34.9, 4.7 and 0.6 mg/ml and at 72 hr these were 16.1, 0.000001 and 0.00001 mg/ml, respectively. In both the cases field bioassays showed affectivity till 7 DAT. Field data indicated that only X1(1 mg/ml) and X2 (0.1 mg/ml) concentrations of mixture were effective till 11 days after treatment. These are the first reports of the toxic effect of wild pomegranate (daru) fruit peel aqueous extract against M. rosaeformis, hence the study suggests possible usage of Punica granatum peel for the control of rose aphids

Prevalence of gestational diabetes mellitus in intrahepatic cholestasis of pregnancy

Background: Incidence of IHCP in Indian population is 0.02%-2.4% and that of GDM is 3.8%-17.9%. Frequent co-existence of both has raised the question of any association. There exists only few studies to prove or disprove any association. Objective of current study was to determine the prevalence of GDM in women with IHCP and to compare the feto-maternal outcome in women with GDM with or without IHCP. Methods: The study was conducted in the Department of Obstetrics and Gynaecology, VMMC and SJH, New Delhi. Women with singleton pregnancy ≥28wks were recruited for the study and further categorized as women with IHCP and women without IHCP according to their diagnosis of IHCP by the RCOG guidelines. OGTT with 75g glucose was done to make the diagnosis of GDM. Management was as per obstetrics protocol and feto-maternal outcomes recorded till delivery. Results: No statistically significant difference in the prevalence of GDM observed in both groups (5.4% in women with IHCP and 8.2% in women without IHCP, p=0.220). Significantly higher number of preterm deliveries (21%, p<0.001), induced labour (53.6%, p<0.001), women undergoing LSCS (46.3%, p<0.001) in women with IHCP. No association of FGR, MSL, Fetal maturity, labour onset, mode of delivery, stillbirth, low APGAR score, NICU admission, or PPH in women with GDM with or without IHCP. Conclusions: The prevalence of GDM is not higher in women with IHCP but significantly higher incidence of preterm delivery, induced labour, and Caesarean sections in women with IHCP. No significant difference in feto-maternal outcome in women with GDM with or without IHCP

Determining Protease Substrate Selectivity and Inhibition by Label-Free Supramolecular Tandem Enzyme Assays

An analytical method has been developed for the continuous monitoring of protease activity on unlabeled peptides in real time by fluorescence spectroscopy. The assay is enabled by a reporter pair comprising the macrocycle cucurbit[7]uril (CB7) and the fluorescent dye acridine orange (AO). CB7 functions by selectively recognizing N-terminal phenylalanine residues as they are produced during the enzymatic cleavage of enkephalin-type peptides by the metalloendopeptidase thermolysin. The substrate peptides (e.g., Thr-Gly-Ala-Phe-Met-NH2) bind to CB7 with moderately high affinity (K ≈ 104 M–1), while their cleavage products (e.g., Phe-Met-NH2) bind very tightly (K \u3e 106 M–1). AO signals the reaction upon its selective displacement from the macrocycle by the high affinity product of proteolysis. The resulting supramolecular tandem enzyme assay effectively measures the kinetics of thermolysin, including the accurate determination of sequence specificity (Ser and Gly instead of Ala), stereospecificity (d-Ala instead of l-Ala), endo- versus exopeptidase activity (indicated by differences in absolute fluorescence response), and sensitivity to terminal charges (−CONH2 vs −COOH). The capability of the tandem assay to measure protease inhibition constants was demonstrated on phosphoramidon as a known inhibitor to afford an inhibition constant of (17.8 ± 0.4) nM. This robust and label-free approach to the study of protease activity and inhibition should be transferable to other endo- and exopeptidases that afford products with N-terminal aromatic amino acids

COVID-19, SARS and MERS:A neurological perspective

Central to COVID-19 pathophysiology is an acute respiratory infection primarily manifesting as pneumonia. Two months into the COVID-19 outbreak, however, a retrospective study in China involving more than 200 participants revealed a neurological component to COVID-19 in a subset of patients. The observed symptoms, the cause of which remains unclear, included impaired consciousness, skeletal muscle injury and acute cerebrovascular disease, and appeared more frequently in severe disease. Since then, findings from several studies have hinted at various possible neurological outcomes in COVID-19 patients. Here, we review the historical association between neurological complications and highly pathological coronaviruses including SARS-CoV, MERS-CoV and SARS-CoV-2. We draw from evidence derived from past coronavirus outbreaks, noting the similarities and differences between SARS and MERS, and the current COVID-19 pandemic. We end by briefly discussing possible mechanisms by which the coronavirus impacts on the human nervous system, as well as neurology-specific considerations that arise from the repercussions of COVID-19.</p