Seasonal-spatial distributions,congener profile,and risk assessment of polychlorinated biphenyls (PCBS) in the surficial sediments from the coastal area of Bangladesh

A comprehensive congener specific assessment of polychlorinated biphenyls (PCBs) was conducted for the first time in Bangladesh. All 209 PCB congeners in the surficial coastal sediments from the coastal areas of Bangladesh were analyzed by GC-MS/MS. The total concentrations of PCBs (∑PCBs) varied from 5.27 to 92.21 and 4.61 to 105.3 ng/g dw in winter and summer, respectively, and the ranges were comparable to or higher than those recorded in the sediments from the coastal areas of India, Korea, China, and Taiwan. The seasonal difference in the levels of PCBs was not statistically significant (p > 0.05). The spatial distribution revealed that the areas with recent urbanization and industrialization (Chittagong, Cox’s Bazar and Sundarbans) were more contaminated with PCBs than the unindustrialized area (Meghna Estuary). Moderately chlorinated (4–6 Cl) homologs dominated PCB profiles. A set of congeners based on their detection frequencies and abundance were identified and categorized as potential environmental marker PCBs, which can be used for the future selective monitoring studies where there would be limitations on whole congener assessment. Ecotoxicologically, the sedimentary PCB concentrations exceeded some of the existing environmental quality standards, suggesting a potential threat to the aquatic organisms in the Bangladeshi coastal areas.     

Evaluation of behavior and endocrinological changes after REM sleep deprivation-induced mania-like behavior in mice

Sleep and Biological Rhythms - The pressure to stay up longer in our modern society due to constant exposure to artificial light and interactive activities; furthermore, social and economic...     

Synthesis,Anti-Fungal Potency and In silico Studies of Novel Steroidal 1,4-Dihydropyridines

Working principle of azoles as antifungals is the inhibition of fungal CYP51/lanosterol-14α-demethylase via selective coordination with heme iron. This interaction can also cause side effects by binding to host lanosterol-14α-demethylase. Hence, it is necessary to design, synthesize and test new antifungal agents that have different structures than those of azoles and other antifungal drugs of choice in clinical practice. Consequently, a series of steroidal 1,4-dihydropyridine analogs 16 – 21 were synthesized and screened for their in vitro anti-fungal activity against three Candida species as steroids-based medications have low toxicity, less vulnerability to multi-drug resistance, and high bioavailability by being capable of penetrating the cell wall and binding to specific receptors. Initially, Claisen–Schmidt condensation takes place between steroidal ketone (dehydroepiandrosterone) and an aromatic aldehyde forming steroidal benzylidene 8 – 13 followed by Hantzsch 1,4-dihydropyridine synthesis resulting in steroidal 1,4-dihydropyridine derivatives 16 – 21 . The results exhibited that compound 17 has significant anti-fungal potential with an MIC value of 750 μg/ml for C. albicans and C. glabrata and 800 μg/ml for C. tropicalis. In silico molecular docking and ADMET studies were also performed for compounds 16 – 21 .     

Potential health risk of heavy metals via consumption of rice and vegetables grown in the industrial areas of Bangladesh

Abstract

Heavy metals are toxic in nature, and their contamination in foodstuff is a matter of concern for human health. The present study was conducted to assess the concentrations of chromium, nickel, copper, arsenic, cadmium, and lead in rice and vegetables and their possible human health risks in Tangail district, Bangladesh. Metals were measured by inductively coupled plasma mass spectrometry (ICP-MS) after microwave digestion system. The average values of Cr, Ni, Cu, As, Cd, and Pb in rice and vegetables were 16.26, 16.11, 13.99, 2.28, 1.86, and 7.93?mg/kg, respectively. The average metal concentration in rice and vegetable species was in the decreasing order of okra?>?chili?>?bitter gourd?>?papaya?>?brinjal?>?bean?>?bottle gourd?>?rice?>?cucumber?>?sponge gourd?>?Indian spinach. The estimated daily intake (EDI) values of all the metals except Cu were higher than the maximum tolerable daily intake (MTDI). The target hazard quotients (THQs) values of Ni, Cu, As, Cd, and Pb exceeded the threshold value of 1 through consumption of rice and vegetables, indicating significant health risks to both adult and children. The target carcinogenic risk (TR) of As and Pb through consumption of rice and vegetables was higher than the USEPA threshold level (10^?4). From the health point of view, this study clearly revealed that consumption of these contaminated rice and vegetables definitely poses carcinogenic and non-carcinogenic risks.     

Asp-376-Glu substitution endows target-site resistance to AHAS inhibitors in Limnocharis flava,an invasive weed in tropical rice fields

Limnocharis flava (L.) Buchenau is a problematic weed in rice fields and water canals of Southeast Asia, and in Malaysia this invasive aquatic weed species has evolved multiple resistance to synthetic auxin herbicide and acetohydroxyacid synthase (AHAS) inhibitors. In this study, it was revealed that, a single nucleotide polymorphism (SNP) at amino acid position 376, where C was substituted to G at the third base of the same codon (GAC to GAG), resulting in Aspartate (Asp) substitution by Glutamate (Glu) was the contributing resistance mechanism in the L. flava population to AHAS inhibitors. In vitro assay further proved that, all the L. flava individuals carrying AHAS resistance mutation exhibited decreased-sensitivity to AHAS inhibitors at the enzyme level. In the bensulfuron-methyl whole-plant bioassay, high resistance indices (RI) of 328- and 437-fold were recorded in the absence and presence of malathion (the P450 inhibitor), respectively. Similarly, translocation and absorption of bensulfuron-methyl in both resistant and susceptible L. flava populations showed no remarkable differences, hence eliminated the possible co-existence of non-target-site resistance mechanism in the resistant L. flava. This study has confirmed another new case of a target-site resistant weed species to AHAS-inhibitors.     

Telomerase reverse transcriptase downregulation by RNA interference modulates endoplasmic reticulum stress and mitochondrial energy production

Molecular Biology Reports - Telomerase is a cancer promoting ribonucleoprotein complex and is a potential therapeutic target for cancer. In this study, the effects of telomerase downregulation on...