Recent Advancements in Schiff Base Fluorescence Chemosensors for the Detection of Heavy Metal Ions

The Schiff base was first synthesized by Hugo Schiff through the condensation reaction of primary amines with carbonyl compounds (aldehyde or ketone) in 1864. Schiff bases exhibit many structural and electrical characteristics that enable their use in a variety of fields, including medical and chemosensing. Schiff bases generate stable complexes when they bind with different metal ions. Schiff bases are employed as fluorescent turn-on/turn-off chemosensors for the detection of various metal cations, such as Hg2+, Cd2+, Cr3+, Pd2+, and As3+ in various materials due to their outstanding coordination ability. This chapter examines a variety of Schiff bases that are employed in chemosensing procedures for various metal ions (such as divalent and trivalent cations) in various biological, agricultural, and environmental settings

Evolution of subgenomic RNA shapes dengue virus adaptation and epidemiological fitness

Changes in dengue virus (DENV) genome affect viral fitness both clinically and epidemiologically. Even in the 3' untranslated region (3' UTR), mutations could affect subgenomic flaviviral RNA (sfRNA) production and its affinity for host proteins, which are necessary for successful viral replication. Indeed, we recently showed that mutations in DENV2 3' UTR of epidemic strains increased sfRNA ability to bind host proteins and reduce interferon expression. However, whether 3' UTR differences shape the overall DENV evolution remains incompletely understood. Herein, we combined RNA phylogeny with phylogenetics to gain insights on sfRNA evolution. We found that sfRNA structures are under purifying selection and highly conserved despite sequence divergence. Only the second flaviviral nuclease-resistant RNA (fNR2) structure of DENV2 sfRNA has undergone strong positive selection. Epidemiological reports suggest that substitutions in fNR2 may drive DENV2 epidemiological fitness, possibly through sfRNA-protein interactions. Collectively, our findings indicate that 3' UTRs are important determinants of DENV fitness in human-mosquito cycles

Inhibitory Metaplasticity in Juvenile Stressed Rats Restores Associative Memory in Adulthood by Regulating Epigenetic Complex G9a/GLP

Abstract Background Exposure to juvenile stress was found to have long-term effects on the plasticity and quality of associative memory in adulthood, but the underlying mechanisms are still poorly understood. Methods Three- to four week-old male Wistar rats were subjected to a 3-day juvenile stress paradigm. Their electrophysiological correlates of memory using the adult hippocampal slice were inspected to detect alterations in long-term potentiation and synaptic tagging and capture model of associativity. These cellular alterations were tied in with the behavioral outcome by subjecting the rats to a step-down inhibitory avoidance paradigm to measure strength in their memory. Given the role of epigenetic response in altering plasticity as a repercussion of juvenile stress, we aimed to chart out the possible epigenetic marker and its regulation in the long-term memory mechanisms using quantitative reverse transcription polymerase chain reaction. Results We demonstrate that even long after the elimination of actual stressors, an inhibitory metaplastic state is evident, which promotes synaptic competition over synaptic cooperation and decline in latency of associative memory in the behavioral paradigm despite the exposure to novelty. Mechanistically, juvenile stress led to a heightened expression of the epigenetic marker G9a/GLP complex, which is thus far ascribed to transcriptional silencing and goal-directed behavior. Conclusions The blockade of the G9a/GLP complex was found to alleviate deficits in long-term plasticity and associative memory during the adulthood of animals exposed to juvenile stress. Our data provide insights on the long-term effects of juvenile stress that involve epigenetic mechanisms, which directly impact long-term plasticity, synaptic tagging and capture, and associative memory. </jats:sec

Lineage shift in Indian strains of Dengue virus serotype-3 (Genotype III), evidenced by detection of lineage IV strains in clinical cases from Kerala

10.1186/1743-422X-10-37Virology Journal103

A Highly Fluorescent Pyrene-based Sensor for Selective Detection of Fe3+ Ion in Aqueous Medium: DFT and Molecular Docking Studies

Abstract In this work, we introduce a highly selective and sensitive fluorescent sensor based on pyrene derivative for Fe(III) ion sensing in DMSO/water media. 2-(pyrene-2-yl)-1-(pyrene-2-ylmethyl)-1H-benzo[d]imidazole (PEBD) receptor was synthesized via simple condensation reaction and confirmed by spectroscopic techniques. The receptor exhibits fluorescence quenching in the presence of Fe(III) ions at 440 nm. ESI-MS and Job’s method were used to confirm the 1:1 molar binding ratio of the receptor PEBD to Fe(III) ions. Using the Benesi-Hildebrand equation the binding constant value was determined as 8.485×103 M-1. Furthermore, the limit of detection (LOD, 3σ/K) value was found to be 1.81µM in DMSO/water (95/5, v/v) media. According to the Environmental Protection Agency (EPA) of the United States, it is lower than the acceptable value of Fe3+ in drinking water (0.3 mg/L). The presence of 14 other metal ions such Co2+, Cr3+, Cu2+, Fe2+, Hg2+, Pb2+, K+, Ni2+, Mg2+, Cd2+, Ca2+, Mn2+, Al3+, and Zn2+ did not interfere with the detection of Fe(III) ions. Computational studies of the receptor PEBD were carried out with density functional theory (DFT) using B3LYP/ 6-311G (d, p), LANL2DZ level of theory. Finally, molecular docking studies have been performed to investigate the Cytochrome P450 1A1(CYP1A1) protein inhibitory action of the receptor PEBD.</jats:p

Recent Advancements in Schiff Base Fluorescence Chemosensors for the Detection of Heavy Metal Ions

The Schiff base was first synthesized by Hugo Schiff through the condensation reaction of primary amines with carbonyl compounds (aldehyde or ketone) in 1864. Schiff bases exhibit many structural and electrical characteristics that enable their use in a variety of fields, including medical and chemosensing. Schiff bases generate stable complexes when they bind with different metal ions. Schiff bases are employed as fluorescent turn-on/turn-off chemosensors for the detection of various metal cations, such as Hg2+, Cd2+, Cr3+, Pd2+, and As3+ in various materials due to their outstanding coordination ability. This chapter examines a variety of Schiff bases that are employed in chemosensing procedures for various metal ions (such as divalent and trivalent cations) in various biological, agricultural, and environmental settings.</jats:p

Molecular characterization of Chikungunya virus isolates from clinical samples and adult <it>Aedes albopictus </it>mosquitoes emerged from larvae from Kerala, South India

<p>Abstract</p> <p>Chikungunya virus (CHIKV), an arthritogenic alphavirus, is transmitted to humans by infected <it>Aedes (Ae.) aegypti </it>and <it>Ae.albopictus </it>mosquitoes. In the study, reverse-transcription PCR (RT PCR) and virus isolation detected CHIKV in patient samples and also in adult <it>Ae.albopictus </it>mosquitoes that was derived from larvae collected during a chikungunya (CHIK) outbreak in Kerala in 2009. The CHIKV strains involved in the outbreak were the East, Central and South African (ECSA) genotype that had the E1 A226V mutation. The viral strains from the mosquitoes and CHIK patients from the same area showed a close relationship based on phylogenetic analysis. Genetic characterization by partial sequencing of non-structural protein 2 (nsP2; 378 bp), envelope E1 (505 bp) and E2 (428 bp) identified one critical mutation in the E2 protein coding region of these CHIKV strains. This novel, non-conservative mutation, L210Q, consistently present in both human and mosquito-derived samples studied, was within the region of the E2 protein (amino acids E2 200-220) that determines mosquito cell infectivity in many alpha viruses. Our results show the involvement of <it>Ae. albopictus </it>in this outbreak in Kerala and appearance of CHIKV with novel genetic changes. Detection of virus in adult mosquitoes, emerged in the laboratory from larvae, also points to the possibility of transovarial transmission (TOT) of mutant CHIKV strains in mosquitoes.</p