Effect of Eu doping on the thermoluminescence of UV and gamma irradiated Mg2B2O5 nanophosphors

This article presents the effect of europium (Eu) doping on the thermoluminescence (TL) of ultraviolet (UV-254 nm) and gamma irradiated triclinic Mg₂B₂O₅ nanophosphors. The diffuse reflectance predicts slight decrease in band gap from 5.18 to 4.99 eV with increasing Eu (1%, 3%, and 5%) content in Mg₂B₂O₅. The TL glow curves of UV irradiated samples comprised of a main peak around 500 K with weak intensity peak/shoulders in low temperature region. Interestingly Eu (3%) doped Mg₂B₂O₅ shows maximum TL intensity with suppression of low temperature shoulder peaks and almost linear UV dose dependent TL response. However, in the case of gamma irradiated Eu (1% and 3% doped) samples, TL glow curve comprises of a main peak around 425–445 K and closely lying peak around 500–515 K with relatively lesser intensity. In case of Eu (5%) doped samples, TL peak around 508 K starts dominating over peak around 425 K. TL of both UV and gamma irradiated samples showed the presence of various deep and shallow defect states within the bandgap of materials having different kinetic parameters, which were determined using TLanal software based on Kiti's general order equation. The present study shows that Eu doped Mg₂B₂O₅ nanophosphors can be tuned for UV and gamma dosimetry.     

Facing the wrath of enigmatic mutations: a review on the emergence of severe acute respiratory syndrome coronavirus 2 variants amid coronavirus disease-19 pandemic

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is an emerging respiratory virus responsible for the ongoing coronavirus disease 19 (COVID-19) pandemic. More than a year into this pandemic, the COVID-19 fatigue is still escalating and takes hold of the entire world population. Driven by the ongoing geographical expansion and upcoming mutations, the COVID-19 pandemic has taken a new shape in the form of emerging SARS-CoV-2 variants. These mutations in the viral spike (S) protein enhance the virulence of SARS-CoV-2 variants by improving viral infectivity, transmissibility and immune evasion abilities. Such variants have resulted in cluster outbreaks and fresh infection waves in various parts of the world with increased disease severity and poor clinical outcomes. Hence, the variants of SARS-CoV-2 pose a threat to human health and public safety. This review enlists the most recent updates regarding the presently characterized variants of SARS-CoV-2 recognized by the global regulatory health authorities (WHO, CDC). Based on the slender literature on SARS-CoV-2 variants, we collate information on the biological implications of these mutations on virus pathology. We also shed light on the efficacy of therapeutics and COVID-19 vaccines against the emerging SARS-CoV-2 variants.     

In silico screening of deleterious single nucleotide polymorphisms (SNPs) and molecular dynamics simulation of disease associated mutations in gene responsible for oculocutaneous albinism type 6 (OCA 6) disorder

Solute carrier family 24 member 5 (SLC24A5) is a gene that is associated with oculocutaneous albinism type 6 (OCA6) disorder and is involved in skin and hair pigmentation. It is involved in the maturation of melanosomes and melanin synthesis. SLC24A5 gene is located in the chromosomal position of 15q21.1. The present study involves the use of computational techniques in order to obtain a detailed picture of the most probable mutations that are associated with SLC24A5. From the observed result it was found that the mutation S145F is most deleterious and disease associated is predicted using several bioinformatics tools. The 3-D structures of native and mutant (S145F) were modeled in order to understand protein functionality using ab initio Robetta server. The modeled structure validation was done with ERRAT, Verify-3D, Procheck and RAMPAGE Ramachandran plot analysis. The most validated structure undergoes molecular dynamics simulations (MDS) study to understand the structural and functional behaviour of the native and mutant proteins. The MDS result showed the more flexibility in the native SLC24A5 structure. Due to mutation in the SLC24A5 protein structure it became more rigid and might disturb the conformational changes and glycosylation function of protein structure and might play role in inducing the OCA6. This study provides a significant insight into the underlying molecular mechanism involved in albinism associated with OCA6. It further helps scientists to develop a drug therapy against OCA 6 disease.

Communicated by Ramaswamy H. Sarma     

Nitric Oxide Production Is Increased in Patients with Inflammatory Myositis

Nitric oxide (NO) production is increased in several inflammatory disorders. We have previously demonstrated higher levels of NO production among patients with rheumatoid arthritis and systemic lupus erythematosus. In this study we measured serum levels of nitrite and citrulline using calorimetric methods as surrogate markers of NO production among patients with inflammatory myositis (IM). Twenty patients with IM and 19 age- and sex-matched controls were studied. Serum nitrite levels were significantly higher among patients than among controls (986.6 +/- 880 and 204.3 +/- 113.9 nmol/ml, respectively; P = 0.001). Serum citrulline levels, too, were significantly higher among patients than among controls (3755.7 +/- 1905.5 and 189 +/- 177.2 nmol/ml, respectively; P < 0.0001). There was a positive correlation between steroid dosage and serum citrulline levels (r = 0.51, P = 0.036) and a negative correlation between steroid dosage and disease duration (r = -0.54, P = 0.025). It was concluded that NO production is increased in patients with IM and those with more active disease, as indicated by higher steroid dosage, have higher serum citrulline levels.     

Intestinal mucins: the binding sites forsalmonella typhimurium

Mucus-bacterial interactions in the gastrointestinal tract and their impact on subsequent enteric infections are poorly delineated. In the present study, we have examined the binding ofSalmonella typhimurium to rat intestinal mucus and characterized a mucus protein (Mucus-Rs) which specifically binds to S. typhimurium. Both virulent (1402/84), and avirulent (SF 1835) S. typhimurium were observed to bind to crude mucus, however, the virulent strain showed 6 fold more binding as compared to avirulent strain. Fractionation of crude mucus on sepharose CL-6B resolved it into three major peaks. Maximal bacterial binding was observed with a high mol. wt. glycoprotein corresponding to neutral mucin. SDS-PAGE of purified protein (termed Mucus-Rs) under non reducing conditions showed it to be a homogenous glycoprotein (mol. wt. 250 kDa), while under reducing conditions, three bands corresponding to mol. wt. of 118,75 and 60 kDa were observed. Pretreatment of Mucus-Rs with pronase, trypsin and sodium metaperiodate markedly inhibited bacterial binding. GLC analysis of Mucus-Rs showed it to contain Mannose, Glucose, Galactose, Glucosamine, Galactosamine and Sialic acid as main sugars. Competitive binding in the presence of various sugars and lectins indicated the involvement of mannose in the mucus-bacterial interactions. The Mucus-Rs binding was highly specific for S. typhimurium; no significant binding was seen with E.coliand V. cholerae. Thus, we conclude that S. typhimurium specifically binds to a 250 kDa neutral mucin of intestinal tract. This binding appears to occur via specific adhesin-receptor interactions involving bacterial pili and mannose of neutral mucin.     

ACE I/D polymorphism in Indian patients with hypertrophic cardiomyopathy and dilated cardiomyopathy

Aim The study was carried to determine the association of angiotensin converting enzyme (ACE) insertion/deletion (I/D) polymorphism with the risk of hypertrophic cardiomyopathy (HCM), dilated cardiomyopathy (DCM), and restrictive cardiomyopathy (RCM). Methods and results A total of 174 patients diagnosed with cardiomyopathy (118 with HCM, 51 with DCM, and 5 with RCM) and 164 ethnically, age- and gender-matched controls were included in the study. ACE I/D genotyping was performed by PCR. In total, 25.86% of the patients were in New York Heart Association (NYHA) class III and IV at presentation. A total of 67.24% patients had dyspnea, 56.89% had angina pectoris, and 25.28% of the patients had at least one event of syncope. Frequency of occurrence of the disease was more in male patients compared to female patients (P < 0.05). After adjustment for age, sex, body mass index (BMI), and smoking habit, the prevalence of ACE DD genotype, and ACE ‘D’ allele was significantly higher in patients as compared to controls and was associated with increased risk (DD: OR 2.11, 95% CI 1.27–3.52, P < 0.05; ‘D’: OR 1.91, 95% CI 1.08–3.35, P < 0.05). The mean septal thickness was higher for DD and ID genotypes (20.40 ± 3.73 mm and 21.82 ± 5.35 mm, respectively) when compared with II genotype (18.63 ± 6.69 mm) in HCM patients, however, the differences were not significant statistically (P > 0.05). The DCM patients with ID genotype showed significantly decreased left ventricular ejection fraction (LVEF) at enrolment (26.50 ± 8.04%) (P = 0.04). Conclusion Our results suggest that D allele of ACE I/D polymorphism significantly influences the HCM and DCM phenotypes.     

Oxidative stress in primary glomerular diseases: a comparative study

Objective To evaluate the status of oxidative stress in patients with different primary glomerular diseases (PGD) which have differential predisposition to renal failure. Methods Seventy-three patients with PGD and 50 controls were enrolled in the study. They were sub-grouped into non-proliferative glomerulonephritis (NPGN) and proliferative glomerulonephritis (PGN). Levels of serum malondialdehyde (MDA), reactive nitrogen intermediates (RNI), plasma total homocysteine (tHcy), urine 8-isoprostane (8-IP), RBC thiols, glutathione-S-transferase (GST) and serum superoxide dismutase (SOD) were measured spectrophotometrically. Results PGD patients showed a significant increase in MDA, RNI, tHcy, 8-IP levels (P < 0.05) and decreased SOD, total thiols and protein bound thiol levels as compared to controls (P < 0.05). Significantly higher levels of tHcy, MDA and 8-IP (P < 0.05) and lower SOD enzyme activity (P < 0.05) were observed in PGN group as compared to NPGN and control groups. These changes remained significant even after adjustment was made for creatinine. Conclusions Oxidative stress in PGN is significantly higher than NPGN, indicating higher oxidative stress in these patients, independent of degree of renal dysfunction.     

Cytotaxonomy of the genusPolystichum in the Western Himalayas

Cytotaxonomical investigations on 11 species from the Western Himalayas show that 8 are diploid and the remaining tetraploid. The numbers for three species are new.P. prescottianum (2x) andP. thomsoni (4x), andP. stimulans (2x) andP. acanthophyllum (4x) are closely related but distinct species pairs.