Decolorization of various dyes by microorganisms and green-synthesized nanoparticles: current and future perspective.

Various types of colored pigments have been recovered naturally from biological sources including shells, flowers, insects, and so on in the past. At present, such natural colored substances (dyes) are replaced by manmade dyes. On the other hand, due to their continuous usage in various purpose, these artificial dyes or colored substances persist in the environmental surroundings. For example, industrial wastewater contains diverse pollutant substances including dyes. Several of these (artificial dyes) were found to be toxic to living organisms. In recent times, microbial-based removal of dye(s) has gained more attention. These methods were relatively inexpensive for eliminating such contaminants in the environmental system. Hence, various researchers were isolated microbes from environmental samples having the capability of decolorizing synthetic dyes from industrial wastewater. Furthermore, the microorganisms which are genetically engineered found higher degradative/decolorize capacity to target compounds in the natural environs. Very few reviews are available on specific dye treatment either by chemical treatments or by bacteria and/or fungal treatments. Here, we have enlightened literature reports on the removal of different dyes in microbes like bacteria (including anaerobic and aerobic), fungi, GEM, and microbial enzymes and also green-synthesized nanoparticles. This up-to-date literature survey will help environmental managements to co-up such contaminates in nature and will help in the decolorization of dyes.

Eco-Friendly Synthesis of MnO2 Nanorods Using Gmelina arborea Fruit Extract and Its Anticancer Potency Against MCF-7 Breast Cancer Cell Line.

INTRODUCTION: Cancer disease is known due to its unregulated proliferation of cells that have evolved from the body's regular cells. The disease develops as a result of epigenetic and genetic modifications, tumor suppressor gene inactivation, and oncogene activation. The present work describes an environmentally benign approach for the synthesis of manganese oxide nanoparticles (MnO2 NPs) using Gmelina arborea fruit extract (GAE) in an aqueous medium. METHODS: The study evaluated the formation of MnO2 NPs and their anticancer efficacy against MCF-7 breast cancer cell line. RESULTS: The formation of MnO2 NPs was confirmed through powder X-ray diffractometer (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and high-resolution transmission electron microscopy (HR-TEM). The crystalline nature of as-prepared MnO2 NPs was evident from XRD pattern. The morphology of the material was studied using SEM analysis, which suggested a rod-like nature with an average diameter of 50 nm. Further, the TEM and HR-TEM images confirmed the rod shape of the as-prepared MnO2 NPs with an interplanar distance of 0.271 nm. In addition, the concentric rings from selected area electron diffraction (SAED) analysis show the crystalline nature of the as-prepared material, which further supports the obtained XRD pattern. The anticancer efficacy of MnO2 NPs was evaluated against MCF-7 breast cancer cell line, which showed up to 96% inhibition of the cells at 400 µg/mL concentration. CONCLUSION: Bio-conjugation of MnO2 NPs can provide enough scope for the therapeutic use of Gmelina arborea, assuming appropriate mechanistic evaluations are conducted.

Characterization and cytotoxic effect of biogenic silver nanoparticles on mitotic chromosomes of Drimia polyantha (Blatt. & McCann) Stearn.

Noble metal nanoparticles afford a tool for investigation and its application in biological systems has had the greatest impact in biology and biomedicine. The present work reports an ecofriendly approach for the synthesis of silver nanoparticles (AgNPs) using an aqueous leaf extract of Getonia floribunda. The silver nanoparticles were characterized by using following instruments viz. UV-vis spectrophotometer, FTIR, XRD AFM and HR-TEM. The UV-vis spectrum showed a characteristic absorption peak at 404 nm. FTIR data reveals the possible involvement of various functional groups for reduction and biocapping of AgNPs. XRD data confirmed the crystalline nature of silver nanoparticles. Morphology, size and distribution of the AgNPs were determined by using AFM and HR-TEM. The average size of AgNPs ranges between 10 and 25 nm and are spherical in shape. The silver nanoparticles were evaluated for their cytotoxic effect on mitotic chromosomes of root meristematic cells of D. polyantha using different concentrations viz. 4, 8, 12 and 16 µg/ml at the time interval of 6, 12, 18 and 24 h. It is evident from the results that the higher concentration of AgNPs found to inhibit mitotic index and caused chromosomal abnormalities such as chromosomal bridge, sticky chromosomes, laggard anaphase, diagonal anaphase, c-metaphase and chromosomal breaks. Therefore, it can be concluded that higher concentrations of silver nanoparticles may induce significant inhibition of root meristem activity and causing DNA damage.

Biosynthesis of silver nanoparticles by leaf extract of Albizia saman (Jacq.) Merr. and their cytotoxic effect on mitotic chromosomes of Drimia indica (Roxb.) Jessop.

Silver nanoparticles synthesized using the leaf extract of Albizia saman (Jacq.) Merr. were tested for induction of cytogenetic abnormality in root tip cells of Drimia indica (Roxb.) Jessop (family Asperagaceae). The leaves are known to be rich in various phytochemicals like flavonoids, glycosides, saponins, steroids, tannins, and terpenoids, which may be responsible for bioreduction, biocapping, and stabilization of nanoparticles. The various instruments used for characterization include UV-VIS spectrophotometer, fourier transform infrared spectroscopy (FTIR), atomic force microscopy (AFM), X-Ray diffractometer (XRD), and high resolution transmission electron microscope (HR-TEM). The present study aims to evaluate the cytotoxic effect of biogenic silver nanoparticles on mitotic chromosomes by using root tip cells of D. indica. The root tips of D. indica was treated with suspensions of silver nanoparticles mixed in distilled water at different concentrations viz., 25, 50, 75, and 100% (w/v) for 6, 12, 18, and 24 h and then fixed in 1:3 ethanol: acetic acid following pre-treatment with 0.05% colchicine for cytological analysis. Silver nanoparticles induced a dose dependent decrease of mitotic index in root meristems. Furthermore, the treated meristem cells showed various types of chromosomal and mitotic aberrations such as anaphase bridge, sticky metaphase, lagging, or forward chromosome indicating genotoxic damage.