In vitro analyses of cerium oxide nanoparticles in degrading anthracene/fluorene and revealing the antibiofilm activity against bacteria and fungi.

A sol-gel method was used to synthesize the cerium dioxide nanoparticles. The nanoparticles formed were then characterized with UV-visible spectrophotometry, Fourier Transform Infrared Spectrophotometer (FTIR), SEM-EDAX, XRD, and Dynamic Light Scattering (DLS). The UV-visible absorbance at 282 nm and characteristic peak at 600-4000 cm-1 provided insight into the formation of cerium dioxide nanoparticles using a chemical method. SEM analysis and EDAX analysis confirmed nanoparticle formation and elements within the nanoparticles based on their irregular morphology. The hydrodynamic size obtained from the DLS analysis was 178.4 nm and the polydispersity was 0.275 nm. Furthermore, XRD results confirmed the crystalline nature of cerium dioxide nanoparticles. Using batch adsorption as a method, the effect of concentration of Polycyclic Aromatic Hydrocarbons (PAH), adsorbent concentration, pH, and irradiation source was investigated. Under UV light conditions, 10 µg/mL cerium dioxide nanoparticle at pH 5 degraded 2 µg/mL of PAH (anthracene and fluorene). Consequently, the synthesized cerium dioxide nanoparticles were effective photocatalysts. For anthracene and fluorene, kinetic studies showed the degradation process followed pseudo-second-order kinetics and Freundlich isotherms. Cerium oxide also exhibited significant antimicrobial and antibiofilm activity against bacteria and fungi. As a result, the cerium dioxide nanoparticle has proved to be a highly effective photocatalytic tool for the degradation of PAHs and exhibits strong antimicrobial activity.

Textile effluents decolourization potential of metal tolerant Aspergillus species and optimization of biomass concentration and temperature.

This research was performed to assess the physicochemical properties of textile effluents collected from different sampling points (industrial park, Hosur, Tamil Nadu, India) and also evaluate the multiple metal tolerance efficiency of pre-isolated Aspergillus flavus. Moreover, their textile effluent decolourization potential was investigated and quantity and temperature required for effective bioremediation was optimized. About 5 textile effluent samples (S0, S1, S2, S3, and S4) were collected from various sampling points and noted that certain physicochemical properties (pH: 9.64 ± 0.38, Turbidity: 18.39 ± 1.4 NTU, Cl-: 3185.38 ± 15.8 mg L-1, BOD: 82.52 ± 6.9 mg L-1, COD: 342.28 ± 8.9 mg L-1, Ni: 74.21 ± 4.31 mg L-1, Cr: 48.52 ± 18.34 mg L-1, Cd: 34.85 ± 1.2 mg L-1, Zn: 25.52 ± 2.4 mg L-1, Pb: 11.25 ± 1.5 mg L-1, Hg: 1.8 ± 0.05 mg L-1, and As: 7.1 ± 0.41 mg L-1) were beyond the permissible limits. The A. flavus, showed remarkable metal tolerance to Pb, As, Cr, Ni, Cu, Cd, Hg, and Zn on PDA plates with elevated dosage up to 1000 µg mL-1. The optimal dosage required for effective decolourization was found as 3 g (48.2%) and compare to dead biomass (42.1%) of A. flavus, the viable biomass showed remarkable decolourization activity on textile effluents in a short duration of treatment process. The optimal temperature for effective decolourization by viable biomass was found at 32 ᵒC. The toxic effects of S4 samples treated at 32 ᵒC on O. sativa as well as brine shrimp larvae were significantly reduced. These findings show that pre-isolated A. flavus viable biomass can be used to decolorize metal-enriched textile effluent. Furthermore, the effectiveness of their metals remediation should be investigated using ex-situ and ex-vivo approaches.

Synthesis of HAp/CS-SA composite for effective removal of highly toxic dyes in aqueous solution.

Textile industry is the major backbone of economy of the developing countries. The major problems associated in the textile factories are release of undesired dye effluents, which is a potential pollution risk for human health as well as the environmental aquatic system. The objective of this study was fabrication of a novel composite to treat textile industry effluents in an ecofriendly manner. In this context, hydroxyapatite (HAp) was derived from the mussel shell biowaste and fabricated with chitosan-sodium alginate through the in-situ method. The prepared HAp/CS-SA composite was physicochemically characterized by using Fourier Transform Infrared Spectroscopy (FTIR), X-ray diffraction (XRD), Field emission scanning electron microscopy with energy dispersive X-ray spectroscopy (FESEM-EDX) and High Resolution-Transmission Electron Microscope (HR-TEM). The photocatalytic activity of the HAp/CS-SA composite was evaluated by using Congo red (CR), Malachite green (MG) and Methylene blue (MB) as model dyes for degradation in aqueous solutions under solar irradiation. The degradation rate was recorded as CR (88%), MG (81%) and MB (93%) respectively within 75 min of irradiation. The degraded end products were subjected to toxicity assessment by evaluating the phytotoxicity on seed germination of Vigna radiata plant in pot study. The degraded end products were also tested for toxic inhibition of E. coli and P. aeruginosa by agar well diffusion method. The prepared HAp/CS-SA composite had an enhanced photocatalytic activity due to the presence of natural biopolymers and their biological properties. HAp/CS-SA composite showed potential dye degradation properties and it could be effective for dye removal from industrial wastewaters.

Bioremediation competence of Aspergillus flavus DDN on pond water contaminated by mining activities.

This research was performed to evaluate the possibilities of reducing the physicochemical properties of polluted pond water situated around the magnesite mine tailing through indigenous metal tolerant fungi. The physicochemical analysis results revealed that most of the physicochemical properties of pond water sample were crossing the permissible limits. From the muddy pond soil sample, Aspergillus flavus DDN was identified (through molecular characterization) as predominant metal tolerant fungal strain and it showed resistance to Cr(VI), Pb(II), Zn(II), Cd(II), and Mg(IV) up to 1000 µg mL-1 concentrations. This strain also effectively reduced (through biosorption) these metals in a short duration of the bioremediation process. In a lab-scale bioremediation study, the A. flavus DDN significantly reduced most of the physicochemical parameters crossing the permissible limit in polluted pond water in the presence of FM1 minimal media in 10 days of incubation. The dissolved oxygen level was significantly increased up to 74.91% from 5.86 ± 0.39 to 10.25 ± 0.95 in 10 days of treatment. The metal reduction and other physicochemical properties reduction were directly related to the biomass of A. flavus DDN. These findings suggest that A. flavus DDN can remove pollutants from magnesite mine tailing polluted pond water because elevated fungal biomass resulted in the highest percentage of pollutant reduction from the sample.

Green fabrication of silver nanoparticles using Chloroxylon swietenia leaves and their application towards dye degradation and food borne pathogens.

Green synthesized silver nanoparticles (AgNPs) are becoming an important candidate for bioremediation and biomedical applications. But in recent trends, more focus is given towards degradation of dyes and application against food pathogens. The synthesis of efficient AgNPs depends on the selection of potential biological material for synthesis. Therefore, in the present study, AgNPs were synthesized using Chloroxylon swietenia. The synthesis AgNPs was confirmed by the formation of dark brown precipitate. Further physicochemical characterization performed using XRD, FTIR, SEM and DLS showed the formation of crystalline structure, presence of functional group from the C. swietenia, dispersed spherical and rod-shaped nanoparticles (6.9 nm) and possess good stability due to the negative partial charges. The dye degrading efficacy of Chloroxylon swietenia mediated synthesized AgNPs (C-AgNPs) was >95%, 90% and >90% tested against Congo red (CR), Coomassie blue (CB) and crystal violet (CV) dye, respectively withing 24 h of treatment under optimum conditions. The antibacterial activity of C-AgNPs (10 mg/mL) was analysed against Staphylococcus nepalensis (3.03 ± 0.35 cm), Staphylococcus gallinarum (2.96 ± 0.15 cm), Bacillus subtilis (2.86 ± 0.23 cm), Enterococcous faecalis (2.8 ± 0.30 cm) and Pseudomonas stuteria (2.06 ± 0.25 cm) using Disc diffusion method, Minimum inhibitory concentration (MIC) and Minimum bactericidal activity (MBC). Therefore, the present study is the first and foremost report on C-AgNPs application as dye degrading and antibacterial agents against food dyes and pathogens. This will provide a major strategy to unveil the complications in food and packaging industries worldwide.

Fungi fabrication, characterization, and anticancer activity of silver nanoparticles using metals resistant Aspergillus niger.

The purpose of this study was to assess the bio-fabrication possibilities of pre-isolated (from bauxite mine tailings) metal-tolerant Aspergillus niger biomass filtrate and the anticancer potential of synthesized silver nanoparticles (AgNPs) tested with a Human Cervical cancer cell line (HeLa cells: Henrietta Lacks cells). The nitrate reduction test demonstrated that A. niger has the ability to reduce nitrate, and filtrate derived from A. niger biomass efficiently fabricated AgNPs from AgNO3, as demonstrated by a visible color change from pale greenish to brownish. The UV-visible spectroscopy analysis revealed an absorbance peak at 435 nm, which corresponded to the AgNPs. These AgNPs have been capped and stabilized with several functional groups related to various bioactive molecules such as aldehyde, benzene rings, aldehydic, amines, alcohols, and carbonyl stretch protein molecules. Fourier-Transform Infrared Spectroscopy (FTIR) analysis confirmed the capping and stabilizing chemical bonding pattern. Scanning Electron Microscopy (SEM) revealed that the synthesized AgNPs were spherical, with an average size of 21.38 nm. This bio-fabricated AgNPs has in-vitro anticancer potential when tested against the HeLa cell line due to its potential size and shape. At 100 g mL-1 concentrations of this bio-fabricated AgNPs, the anticancer activity percentage was found to be 70.2%, and the IC50 value was found to be 66.32 g m-1. These findings demonstrated that the metal-tolerant A. niger cell filtrate could produce AgNPs with anticancer potential.

A novel synthesis, analysis and evaluation of Musa coccinea based zero valent iron nanoparticles for antimicrobial and antioxidant.

Zerovalent Iron Nanoparticles (MC-ZVI NPs) were synthesized from Musa coocinea peel extract as reducing and stabilizing agent using a novel synthesis technique. The synthesis of MC-ZVI NPs was confirmed using UV-vis spectroscopy showing a sharp absorption peak at 341 nm. Further the chemical and structural characterization of MC-ZVI NPs were performed using Fourier Transform Infrared spectroscopy (FTIR), Scanning Electron Microscopy (SEM), and Dynamic Light Scattering technique (DLS). FTIR analysis revealed the presence of phytochemical molecules associated with the MC-ZVI NPs. SEM analysis revealed the synthesized MC-ZVI NPs were in spherical shaped, while DLS analysis confirmed the synthesis of poly dispersed and non-homogenous MC-ZVI NPs. The antimicrobial efficacy of MC-ZVI NPs synthesized using Musa coccinea peel extract was tested against bacterial (Escherichia coli, Staphylococcus aureus, Klebsiella pneumoniae, and Bacillus subtilis) and fungal (Aspergillus niger) pathogens. But MC-ZVI NPs exhibited maximum of 19 mm zone of inhibition against B. subtilis and A. niger. Further the free radical scavenging activity MC-ZVI NPs was confirmed using DPPH, hydroxyl radical, hydrogen peroxide, FRAP assay showing displayed effective antioxidant activity. Thus, the present idea will give a fast and cost effective approach to synthesize MC-ZVI NPs with antimicrobial property for application in biomedical purposes.

FDPS cooperates with PTEN loss to promote prostate cancer progression through modulation of small GTPases/AKT axis.

Farnesyl diphosphate synthase (FDPS), a mevalonate pathway enzyme, is highly expressed in several cancers, including prostate cancer (PCa). To date, the mechanistic, functional, and clinical significance of FDPS in cancer remains unexplored. We evaluated the FDPS expression and its cancer-associated phenotypes using in vitro and in vivo methods in PTEN-deficient and sufficient human and mouse PCa cells and tumors. Interestingly, FDPS overexpression synergizes with PTEN deficiency in PTEN conditionally knockout mice (P < 0.05) and expressed significantly higher in human (P < 0.001) PCa tissues, cell lines, and murine tumoroids compared to respective controls. In silico analysis revealed that FDPS is associated with increasing Gleason score, PTEN functionally deficient status, and poor survival of PCa. Ectopic overexpression of FDPS promotes oncogenic phenotypes such as colony formation (P < 0.01) and proliferation (P < 0.01) through activation of AKT and ERK signaling by prenylating Rho A, Rho G, and CDC42 small GTPases. Of interest, knockdown of FDPS in PCa cells exhibits decreased colony growth and proliferation (P < 0.001) by modulating AKT and ERK pathways. Further, genetic and pharmacological inhibition of PI3K but not AKT reduced FDPS expression. Pharmacological targeting of FDPS by zoledronic acid (ZOL), which is already in clinics, exhibit reduced growth and clonogenicity of human and murine PCa cells (P < 0.01) and 3D tumoroids (P < 0.02) by disrupting AKT and ERK signaling through direct interference of small GTPases protein prenylation. Thus, FDPS plays an oncogenic role in PTEN-deficient PCa through GTPase/AKT axis. Identifying mevalonate pathway proteins could serve as a therapeutic target in PTEN dysregulated tumors.