Distribution and risk assessment of pesticide pollution in small streams adjoining paddy fields.

The present investigation was planned to bridge the knowledge gap on spatiotemporal variations of pesticide pollution in small streams adjacent to paddy fields, and to visualize the associated risks in the aquatic ecosystems. We screened 106 pesticides using GCMSMS and LCMSMS from 10 small streams (n = 212, surface water samples) adjacent to paddy fields over seven months. Fifty-five pesticides were detected across different streams and months. The highest mean concentration was detected for fenobucarb (272 ng L-1), followed by thiamethoxam (199 ng L-1). The highest maximum concentration was detected for thiamethoxam ( 13,264 ng L-1), followed by triflumezopyrim ( 11,505 ng L-1). The highest detection frequency was recorded for fenobucarb (80.00%), followed by pretilachlor (79.00%). Out of the ten streams, Attabira stream had the highest mean number of pesticides detected in each sample. Maximum number of pesticides were detected in October followed by September. Pesticides namely, hexaconazole, pretilachlor, tricyclazole, fenobucarb and thiamethoxam were consistently detected across all streams. The risk assessment against the fishes, micro-invertebrates and algae were measured by risk quotient index (RQ). Twenty-five pesticides out of the detected pesticides (n = 55) had risk quotient values greater than 1. The highest RQmax values were observed in case of fenpropathrin followed by cyfluthrin-3. The highest RQmean value was observed in case of cyfluthrin, indicating its higher toxicity to fishes. The present study reveals that small streams are polluted with pesticides and there is a need to develop strategies and policy interventions in regularizing the pesticide uses for reducing the pesticide pollution in aquatic systems.

Small Volume Microrheology to Evaluate Viscoelastic Properties of Nucleic Acid-Based Supra-Assemblies.

Particle tracking (PT) microrheology is a passive microrheological approach that characterizes material properties of soft matter. Multicomponent materials with the ability to create extensive crosslinking, such as supra-assemblies, may exhibit a complex interplay of viscous and elastic properties with a substantial contribution of liquid phase still diffusing through the system. Microrheology analyzes the motion of microscopic beads immersed in a sample, making it possible to evaluate the rheological properties of biological supra-assemblies. This method requires only a small volume of the sample and a relatively simple, inexpensive experimental setup. The objective of this chapter is to describe the experimental procedures for the observation of particle motion, calibration of an optical setup for particle tracking, preparation of imaging chambers, and the use of image analysis software for particle tracking in viscoelastic nucleic acid-based supra-assemblies.

Optical, structural, and biological properties of silver nanoclusters formed within the loop of a C-12 hairpin sequence.

Silver nanoclusters (AgNCs) are the next-generation nanomaterials representing supra-atomic structures where silver atoms are organized in a particular geometry. DNA can effectively template and stabilize these novel fluorescent AgNCs. Only a few atoms in size - the properties of nanoclusters can be tuned using only single nucleobase replacement of C-rich templating DNA sequences. A high degree of control over the structure of AgNC could greatly contribute to the ability to fine-tune the properties of silver nanoclusters. In this study, we explore the properties of AgNCs formed on a short DNA sequence with a C12 hairpin loop structure (AgNC@hpC12). We identify three types of cytosines based on their involvement in the stabilization of AgNCs. Computational and experimental results suggest an elongated cluster shape with 10 silver atoms. We found that the properties of the AgNCs depend on the overall structure and relative position of the silver atoms. The emission pattern of the AgNCs depends strongly on the charge distribution, while all silver atoms and some DNA bases are involved in optical transitions based on molecular orbital (MO) visualization. We also characterize the antibacterial properties of silver nanoclusters and propose a possible mechanism of action based on the interactions of AgNCs with molecular oxygen.

DNA-Templated Silver Nanoclusters as Dual-Mode Sensitive Probes for Self-Powered Biosensor Fueled by Glucose.

Nanomaterials have been extensively explored in developing sensors due to their unique properties, contributing to the development of reliable sensor designs with improved sensitivity and specificity. Herein, we propose the construction of a fluorescent/electrochemical dual-mode self-powered biosensor for advanced biosensing using DNA-templated silver nanoclusters (AgNCs@DNA). AgNC@DNA, due to its small size, exhibits advantageous characteristics as an optical probe. We investigated the sensing efficacy of AgNCs@DNA as a fluorescent probe for glucose detection. Fluorescence emitted by AgNCs@DNA served as the readout signal as a response to more H2O2 being generated by glucose oxidase for increasing glucose levels. The second readout signal of this dual-mode biosensor was utilized via the electrochemical route, where AgNCs served as charge mediators between the glucose oxidase (GOx) enzyme and carbon working electrode during the oxidation process of glucose catalyzed by GOx. The developed biosensor features low-level limits of detection (LODs), ~23 µM for optical and ~29 µM for electrochemical readout, which are much lower than the typical glucose concentrations found in body fluids, including blood, urine, tears, and sweat. The low LODs, simultaneous utilization of different readout strategies, and self-powered design demonstrated in this study open new prospects for developing next-generation biosensor devices.

Radiosensitivity of seedling traits to varying gamma doses, optimum dose determination and variation in determined doses due to different time of sowings after irradiation and methods of irradiation in faba bean genotypes.

PURPOSE: Three experiments were conducted to assess the effect of different doses of gamma radiation on various seedling traits; determine the optimum doses of gamma radiation for different faba bean genotypes; find out the variation in optimum doses with respect to the different times of sowings after irradiation and methods of irradiation. MATERIALS AND METHODS: Five faba bean genotypes viz., L-2013-060, L-2013-092, Anandnagar Local, Gazipur Local and Bangla Gangachar were used in these experiments. In Experiment I, seeds of five experimental genotypes were exposed to different doses (100 Gy 200 Gy, 300 Gy, 400 Gy, 500 Gy, 600 Gy, 700 Gy and 800 Gy) of gamma radiation and were sown immediately after irradiation. In Experiment II, seeds of Bangla Gangachar and L-2013-060 were exposed to varying doses (100-800 Gy) of gamma radiation and were sown at seven sowings starting from 0 h to 24 h at 4-h intervals after irradiation. In Experiment III, L-2013-092 genotypes was exposed to different doses (100 -800 Gy) of gamma radiation with two different methods of irradiation. RESULTS: In Experiment I, the lethal dose 50 (LD50) values have arrived at 140 Gy, 669 Gy, 575 Gy, 386 Gy and 158 Gy for L-2013-060, L-2013-092, Anandnagar Local, Gazipur Local and Bangla Gangachar, respectively. The growth reduction 50 (GR50) doses for different seedling traits ranged from 130 Gy to 320 Gy for L-2013-060, 250 Gy to 480 Gy for L-2013-092, 130 Gy to 370 Gy for Anandnagar Local, 200 Gy to 350 Gy for Gazipur Local and 250 Gy to 400 Gy for Bangla Gangachar. In Experiment II, the values for LD50 of the genotypes Bangla Gangachar and L-2013-060 were significantly singular for different time intervals of sowing. The values of GR50 for most of the seedling traits were found to increase with the delay in sowing after irradiation from 4 to 24 h when compared with the immediately sown seed lots. In Experiment III, LD50 for L-2013-092 was 337 Gy with Method 1 and 669 Gy with Method 2. In Method 1, most of the growth parameters attained GR50 doses lower than Method 2. The first method was found to increase the radiosensitivity of L-2013-092. CONCLUSION: Every experimental genotype used in these three experiments showed dose-dependent retardation of different seedling traits. These optimized doses may be employed to establish mutant populations for exploiting the novel traits of faba bean. The time of sowing after irradiation and method of irradiation was found to be essential for confirming optimum doses.

Exploring the Immunomodulatory Aspect of Mesenchymal Stem Cells for Treatment of Severe Coronavirus Disease 19.

Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) is an enveloped, positive sense, single stranded RNA (+ssRNA) virus, belonging to the genus Betacoronavirus and family Coronaviridae. It is primarily transmitted from infected persons to healthy ones through inhalation of virus-laden respiratory droplets. After an average incubation period of 2-14 days, the majority of infected individuals remain asymptomatic and/or mildly symptomatic, whereas the remaining individuals manifest a myriad of clinical symptoms, including fever, sore throat, dry cough, fatigue, chest pain, and breathlessness. SARS-CoV-2 exploits the angiotensin converting enzyme 2 (ACE-2) receptor for cellular invasion, and lungs are amongst the most adversely affected organs in the body. Thereupon, immune responses are elicited, which may devolve into a cytokine storm characterized by enhanced secretion of multitude of inflammatory cytokines/chemokines and growth factors, such as interleukin (IL)-2, IL-6, IL-7, IL-8, IL-9, tumor necrosis factor alpha (TNF-α), granulocyte colony-stimulating factor (GCSF), basic fibroblast growth factor 2 (bFGF2), monocyte chemotactic protein-1 (MCP1), interferon-inducible protein 10 (IP10), macrophage inflammatory protein 1A (MIP1A), platelet-derived growth factor subunit B (PDGFB), and vascular endothelial factor (VEGF)-A. The systemic persistence of inflammatory molecules causes widespread histological injury, leading to functional deterioration of the infected organ(s). Although multiple treatment modalities with varying effectiveness are being employed, nevertheless, there is no curative COVID-19 therapy available to date. In this regard, one plausible supportive therapeutic modality may involve administration of mesenchymal stem cells (MSCs) and/or MSC-derived bioactive factors-based secretome to critically ill COVID-19 patients with the intention of accomplishing better clinical outcome owing to their empirically established beneficial effects. MSCs are well established adult stem cells (ASCs) with respect to their immunomodulatory, anti-inflammatory, anti-oxidative, anti-apoptotic, pro-angiogenic, and pro-regenerative properties. The immunomodulatory capabilities of MSCs are not constitutive but rather are highly dependent on a holistic niche. Following intravenous infusion, MSCs are known to undergo considerable histological trapping in the lungs and, therefore, become well positioned to directly engage with lung infiltrating immune cells, and thereby mitigate excessive inflammation and reverse/regenerate damaged alveolar epithelial cells and associated tissue post SARS-CoV-2 infection. Considering the myriad of abovementioned biologically beneficial properties and emerging translational insights, MSCs may be used as potential supportive therapy to counteract cytokine storms and reduce disease severity, thereby facilitating speedy recovery and health restoration.

Synthesis and biological evaluation of some 2-(3,5-dimethyl-1H-pyrazol-1-yl)-1-arylethanones: antibacterial, DNA photocleavage, and anticancer activities.

In continuation of our efforts to find new biologically active agents, regioselective synthesis of a series of 2-(3,5-dimethyl-1H-pyrazol-1-yl)-1-arylethanones 4a-k has been achieved under facile, extremely mild and greener reaction conditions with excellent yields. Moreover, one pot multicomponent reaction has also been reinvestigated under previously reported solvent conditions to prepare 4a-b and found that the reaction generates significant amount of side products. The chemical structures of 4a-k were established on the basis of a combined use of IR, NMR ((1)H, (13)C) spectroscopy, mass spectrometry and elemental analysis. All the compounds were evaluated for their antibacterial, DNA photocleavage and anticancer activities. Among all, 2-(3,5-dimethyl-1H-pyrazol-1-yl)-1-(naphth-2-yl)ethanone 4j displayed good inhibitory profile against Escherichia coli and Staphylococcus aureus which was about 50% and 25% of the Ampicillin (standard drug), respectively. The compounds, 4a and 4f showed relatively moderate inhibition against Psuedomonas aeruginosa and E. coli. In DNA photocleavage study, compounds 4c and 4d were found to be highly active and completely degraded both forms of DNA (SC and OC), even at a very low concentration of 1 µg (4c) under irradiation of UV light. However, 4h and 4f resulted in complete DNA degradation at 30 µg concentration. Moreover, 4h showed fluorescence at 15 µg concentration and increased the intensity of both bands of DNA (SC and OC) as compared to control. On the other hand, to valorize the biological potential, the compounds were screened for their cytotoxic activity on colon (HCT116 and HT29), prostate (DU145), ovarian (SKOV3) and lung (A549) cancer cell lines. The compound 4j was found to be cytotoxic to all the cancer cell lines, except SKOV3, with more selectivity towards the colon cancer cell lines (HCT116, HT29) and A549 lung cancer cell line. On A549 lung cancer cell line, 4j and 4k exhibited similar potency as carboplatin in inhibiting cell viability.

Bis[mu-[6-(hydroxymethyl)-2-pyridyl]methanolato-kappa(3)N,O:O]bis[[2,6-bis(hydroxymethyl)pyridine-kappa(3)O,N,O']copper(II)] diacetate.

The title dinuclear Cu(II) complex, [Cu(2)(C(7)H(8)NO(2))(2)(C(7)H(9)NO(2))(2)](CH(3)COO)(2), has been synthesized by the reaction of Cu(CH(3)COO)(2).H(2)O with pdmH(2) (pdmH(2) is pyridine-2,6-diyldimethanol) in the presence of tetrabutylammonium hydroxide. The title complex contains a centrosymmetric Cu(2)O(2) core and each Cu(II) atom has distorted octahedral geometry. Molecular [Cu(2)(pdmH)(2)(pdmH(2))](2+) cations are connected by hydrogen bonds involving the CH(3)COO(-) anions, forming one-dimensional chains along the a axis.