Simultaneous electrochemical determination of persistent petrogenic organic pollutants based on AgNPs synthesized using carbon dots derived from mushroom.

Polycyclic aromatic hydrocarbons (PAHs) are highly carcinogenic substances and accumulate in water bodies through various industries. Due to their harmful effects on humans, it is very important to monitor PAHs in various water resources. In the present work, we report an electrochemical sensor based on silver nanoparticles synthesized using mushroom-derived carbon dots for the simultaneous determination of anthracene and naphthalene, for the first time. Pleurotus species mushroom was used to synthesize the carbon dots (C-dots) via the hydrothermal method and these C-dots were used as a reducing agent for the synthesis of silver nanoparticles (AgNPs). The synthesized AgNPs have been characterized through UV-Visible and FTIR spectroscopy, DLS, XRD, XPS, FE-SEM, and HR-TEM. Well-characterized AgNPs were used to modify glassy carbon electrodes (GCEs) by the drop-casting method. Ag-NPs/GCE has shown strong electrochemical activity towards the oxidation of anthracene and naphthalene at well-separated potentials in phosphate buffer saline (PBS) at pH 7.0. The sensor exhibited a wide linear working range of 250 nM to 1.15 mM for anthracene and 500 nM to 842 µM for naphthalene with the corresponding lowest detection limits (LODs) of 112 nM and 383 nM respectively with extraordinary anti-interference ability against many possible interferents. The fabricated sensor showed high stability and reproducibility. The usefulness of the sensor for the monitoring of anthracene and naphthalene in a seashore soil sample has been demonstrated by the standard addition method. The sensor gave better results with a high recovery percentage indicating the first-ever device to detect two PAHs at the single electrode with the best analytical results.

DNA-functionalized carbon quantum dots for electrochemical detection of pyocyanin: A quorum sensing molecule in Pseudomonas aeruginosa.

The electrochemical biosensing strategy for pyocyanin (PYO), a virulent quorum-sensing molecule responsible for Pseudomonas aeruginosa infections, was developed by mimicking its extracellular DNA interaction. Calf thymus DNA (ct-DNA) functionalized amine-containing carbon quantum dots (CQDs) were used as a biomimetic receptor for electrochemical sensing of PYO as low as 37 nM in real urine sample. The ct-DNA-based biosensor enabled the selective measurement of PYO in the presence of other interfering species. Calibration and validation of the PYO sensor platform were demonstrated in buffer solution (0-100 µM), microbial culture media (0-100 µM), artificial urine (0-400 µM), and real urine sample (0-250 µM). The sensor capability was successfully implemented for point-of-care (POC) detection of PYO release from Pseudomonas aeruginosa strains during lag and stationary phases. Cross-reactivity of the sensing platform was also tested in other bacterial species such as Bacillus subtilis, Escherichia coli, Klebsiella pneumoniae, Shigella dysenteriae, Staphylococcus aureus, and Streptococcus pneumoniae. Potential clinical implementation of the ct-DNA-based sensor was manifested in detecting the PYO in P. aeruginosa cultured baby diaper and sanitary napkin. Our results highlight that the newly developed ct-DNA-based sensing platform can be used as a potential candidate for real-time POC diagnosis of Pseudomonas aeruginosa infection in clinical samples.

Macrocyclic "tet a"-Derived Cobalt(III) Complex with a N,N'-Disubstituted Hexadentate Ligand: Crystal Structure, Photonuclease Activity, and as a Photosensitizer.

A cobalt(III) complex, [Co(L)]Cl (complex 1, where L = 1,8-[N,N-bis{(3-formyl-2-hydroxy-5-methyl)benzyl}]-1,4,8,11-tetraaza-5,5,7,12,12,14-hexamethylcyclotetradecane) with distorted octahedral geometry has been synthesized and characterized using various spectroscopic techniques. The structure of the ligand has remarkably rich hydrogen intermolecular interactions such as H···H, H···C/C···H, and H···O/O···H that vary with the presence of the metal ion, and the structure of complex 1 has Cl···H interactions; this result has been proved by Hirshfeld surface and two-dimensional (2D) fingerprint maps analyses. The complex exhibits a quasi-reversible Co(III)/Co(II) redox couple with E 1/2 = -0.76 V. Calf thymus DNA (CT DNA) binding abilities of the ligand and complex 1 were confirmed by spectroscopic and electrochemical analyses. According to absorption studies, the ligand and complex 1 bind to CT DNA via intercalative binding mode, with intrinsic binding strengths of 1.41 × 103 and 8.64 × 103 M-1, respectively. A gel electrophoresis assay shows that complex 1 promotes the pUC19 DNA cleavage under dark and light irradiation conditions. Complex 1 has superior antimicrobial activity than the ligand. The cytotoxicity of complex 1 was tested against MDA-MB-231 breast cancer cells with values of IC50 of 1.369 µg mL-1 in the dark and 0.9034 µg mL-1 after light irradiation. Besides, cell morphological studies confirmed the morphological changes with AO/EB dual staining, reactive oxygen species (ROS) staining, mitochondria staining, and Hoechst staining on MDA-MB-231 cancer cells by fluorescence microscopy. Complex 1 was found to be a potent antiproliferative agent against MDA-MB-231 cells, and it can induce mitochondrial-mediated and caspase-dependent apoptosis with activation of downregulated caspases. The biotoxicity assay of complex 1 on the development of Artemia nauplii was evaluated at an IC50 value of 200 µg mL-1 and with excellent biocompatibility.

Particle size influence on the composition of sugars in corncob hemicellulose hydrolysate for xylose fermentation by Meyerozyma caribbica.

The xylitol production was performed with acidophilic Meyerozyma caribbica. The particle size of 0.02 ± 0.01 to 0.1 ± 0.05 mm was rich in glucose (12.0 ± 0.5 g/L), whereas 0.5 ± 0.25 to 2.0 ± 0.5 mm had a high content of xylose (8.0 ± 0.5 g/L). The xylitol production in the synthetic, non-detoxified and detoxified hydrolysate media was studied (50 ± 0.5 g/L) using 10% v/v non - induced cells of M. caribbica for 120 h. At the end of fermentation with the specific growth rate of 0.056 ± 0.01 (µ), xylitol yields of 45.00 ± 1.00%, 10.00 ± 1.00% and 54.00 ± 1.00% were obtained. The detoxification of the hydrolysate prepared using an identified corncob particle size of 0.5 ± 0.25 to 2.0 ± 0.5 mm could be used as the prospective pretreatment process for ecofriendly and industrial scale production of xylitol with M. caribbica.

In situ conservation of endangered tree species (Elaeocarpus venustus Bedd.) habitated in Agasthiyamalai Biosphere Reserve, Southern Western Ghats, India.

Elaeocarpus venustus is an endemic as well as endangered tree species habitated in the wet evergreen forests of Southern Western Ghats (SWG), India. Due to insufficient natural regeneration, low seedling tendency, and prevailing anthropogenic disturbances, their distribution has been shrinking in their native environment. Towards conserving this endangered species, we have attempted to propagate E. venustus in its habitat by adopting vegetative propagation techniques of cutting and air layering through growth hormones. Significant growth has been observed by providing 2 mM concentration of indole-3-butyric acid (IBA) for both cutting and air layering. Higher rooting response has been observed through cutting and air layering techniques during monsoon periods. Based on the results of the study, we suggest that the cutting and air layering techniques can be employed as promising strategies towards the in situ conservation and promotion of Elaeocarpus venustus tree species as well as other endangered species in Western Ghats.

Studies on the influence of natural resource utilization by humans on foraging behavior of honey bees at rural ecosystems.

Human utilization of natural resources acts as a main driver in altering the ecosystem service and functions. Apart from indirect influence, these human activities also tempt for the behavioral shift in insects especially in honey bees. The foraging behavior of honey bees from the natural floral resources to the man-made food sources eventually degrade the ecosystem's services and cause declining of the honey bee population. Understanding this foraging behavior of bees could help in opting for viable conservation measures for honey bees. In order to understand the influence of human utilization of natural resources on the foraging behavior of bees and its negative impacts on the bee population, the study was carried out in the sites where humans collect palm sap. Palm sap collectors used different containers (mud pots and pet bottles) to collect the palm sap from Borassus flabellifer. The number of containers per tree, volume of palm sap per container/tree, bee visiting frequency, and bee mortality per container/tree were measured at different ecosystems. Palm saps were collected freshly and volatile compounds of samples were identified using FT-IR and GC-MS analysis. The identified volatile compounds were used to study the interaction between volatile compounds and odorant-binding proteins (OBPs) of honey bees for understanding the foraging behavior of bees using in silico approach. Our results clearly showed that bee visitation frequency was directly correlated (0.94) with bee mortality in palm sap in different study sites. The average number of bee mortality was recorded as 491.2 ± 23.48 bees per container/tree/day. GC-MS analyses revealed the presence of 35 volatile compounds in collected palm sap from different study sites. Furthermore, molecular docking studies were performed for all 35 palm volatile compounds OBPs of honey bees to analyze their binding affinities. Docking studies showed that 1-methylbutylmandelate and 6-(hydroxymethyl)-1,4,4-trimethylbicyclo [3.1.0] hexan-2-ol have high binding affinity with OBP residues of bees. These volatile compounds might act as an attractant for bee populations for their foraging behavior. Based on this study, we conclude that human utilization of palm sap has created new ecological niches which highly alters the foraging behavior of bees and results in declining bee populations.

Bioelectricity generation by natural microflora of septic tank wastewater (STWW) and biodegradation of persistent petrogenic pollutants by basidiomycetes fungi: An integrated microbial fuel cell system.

The microbial fuel cell is a unique advantageous technology for the scientific community with the simultaneous generation of green energy along with bioelectroremediation of persistent hazardous materials. In this work, a novel approach of integrated system with bioelectricity generation from septic tank wastewater by native microflora in the anode chamber, while Psathyrella candolleana with higher ligninolytic enzyme activity was employed at cathode chamber for the biodegradation of polycyclic aromatic hydrocarbons (PAHs). Six MFC systems designated as MFC1, MFC2, MFC3, MFC4, MFC5, and MFC6 were experimented with different conditions. MFC1 system using natural microflora of STWW (100%) at anode chamber and K3[Fe(CN)6] as cathode buffer showed a power density and current density of 110 ± 10 mW/m2 and 90 ± 10 mA/m2 respectively. In the other five MFC systems 100% STWW was used at the anode and basidiomycetes fungi in the presence or absence of individual PAHs (naphthalene, acenaphthene, fluorene, and anthracene) at the cathode. MFC2, MFC3, MFC4, MFC5, and MFC6 had showed power density of 132 ± 17 mW/m2, 138 ± 20 mW/m2, 139 ± 25 mW/m2, and 147 ± 10 mW/m2 respectively. MFC2, MFC3, MFC4, MFC5, and MFC6 had showed current density of 497 ± 17 mA/m2, 519 ± 10 mA/m2, 522 ± 21 mA/m2 and 525 ± 20 mA/m2 respectively. In all the MFC systems, the electrochemical activity of anode biofilm was evaluated by cyclic voltammetry analysis and biofilms on all the MFC systems electrode surface were visualized by confocal laser scanning microscope. Biodegradation of PAHs during MFC experimentations in the cathode chamber was estimated by UV-Vis spectrophotometer. Overall, MFC6 system achieved maximum power density production of 525 ± 20 mA/m2 with 77% of chemical oxygen demand removal and 54% of coulombic efficiency at the anode chamber and higher anthracene biodegradation (62 ± 1.13%) at the cathode chamber by the selected Psathyrella candolleana at 14th day. The present natural microflora - basidiomycetes fungal coupled MFC system offers excellent opening towards the simultaneous generation of green electricity and PAHs bioelectroremediation.

Fermentative hydrogen production and bioelectricity generation from food based industrial waste: An integrative approach.

In the present study, isolation and identification of hydrogen producing strains from sugar and food industry wastewater were reported. From 48 isolates in both the wastewater, initial batch studies led to the use of four effective strains, which were identified using 16S rRNA gene sequencing as Bacillus thuringiensis-FH1, Comamonas testosteroni-FB1, Klebsiella pneumoniae-FA2 and Bacillus cereus-SB2, respectively. Further optimization studies were done at various pH values (5-8) and wastewater concentrations (10-100%). In the optimized batch experimentation, K. pneumoniae-FA2 excelled with the maximum cumulative hydrogen production of 880.93 ± 44.0 mL/L. A 3 L bioreactor was employed for effective hydrogen production, which conferred that K. pneumoniae-FA2, surpassed the other three with the maximum hydrogen yield of 3.79 ± 0.04 mol H2/mol glucose. Bioelectricity production by K. pneumoniae-FA2 was also investigated in the microbial fuel cell at the optimized conditions to demonstrate its versatility in energy applications.

Evaluation of antidiabetic activity of Pleurotus pulmonarius against streptozotocin-nicotinamide induced diabetic wistar albino rats.

The current research aims to evaluate the antidiabetic properties of Pleurotus pulmonarius, an edible basidiomycetes mushroom fungi in diabetic induced wistar albino rats. Mycelial Hot Water Extracts (HWE) and Acetone Extracts (AE) of Pleurotus pulmonarius was orally administrated to STZ-NA induced (55 mg/kilogram body weight) diabetic wistar albino rats at a concentration of 200 and 400 mg/kg for 4 weeks. The outcomes revealed that the HWE of Pleurotus pulmonarius resulted in a significant (p < 0.001) reduction in blood glucose level. A noteworthy (p < 0.001) reduction in serum lipid profile and elevation in High-Density Lipoprotein Cholesterol (HDL-C) after administration with HWE, also demonstrating the protective effects of HWE in diabetes-related complications. Besides all antidiabetic parameters, pathological morphology of the pancreas, liver and kidney are regularised. This observation indicated that HWE of Pleurotus pulmonarius possessed higher antidiabetic activity than AE. Besides, HWE also promoted a significant control of alpha amylase enzyme in a concentration-dependent manner with a maximum activity of 99.23% inhibition at 1000 µg/ml. The outcomes of the present study indicated that the HWE possesses a potential antidiabetic activity both in vitro and in vivo. Thus, it can be used as a nontoxic complementary drug in the controlling of diabetes and related complications, thus providing scientific authentication of its use as an antidiabetic agent.

Environmental friendly synthesis of TiO2-ZnO nanocomposite catalyst and silver nanomaterilas for the enhanced production of biodiesel from Ulva lactuca seaweed and potential antimicrobial properties against the microbial pathogens.

TiO2-ZnO heterogeneous catalytic system provides a good replacement of a homogeneous catalytic reaction due to its easier recovery. In this study, biodiesel was produced from Ulva lactuca seaweeds using TiO2-ZnO nanocomposite catalysts with particle size of ~12 nm. The size controlled TiO2-ZnO nanocomposite was characterized by powder XRD analysis and TEM. The result of that TiO2-ZnO catalyst is a promising catalyst for the production of biodiesel under mild reaction conditions and high yield of hydroxydecanoic acid conversion of 82.8%. The various conditions optimized for the higher conversion to FAME (15.8 ml of FAME) were 4 wt% catalysts at 4 h under 60 °C and further there is no increase of conversion to FAME above 60 °C-80 °C. The total product yield was calculated as 82.8% of conversion to FAME. The evaluated biodiesel was found to be up to the mark of ASTM standards. The silver nanoparticles (AgNPs) were synthesized by using leftover biomass of algae obtaining after lipid extraction of U.lactuca. AgNPs particle size was achieved as ~12 nm and was confirmed by UV-Visible spectroscopy, XRD and TEM analysis. Antibacterial activities of the synthesized AgNPs were analyzed and compared. The antibacterial activity was excellent against bacterial pathogens and treatment against P. vulgaris shows the maximum zone of inhibition (13.8 mm). The present work identified that the unutilized bioresource such as U.lactuca can be effectively utilized for biodiesel production so as to replace fossil fuel usage.