Chromate Removal by Enterobacter cloacae Strain UT25 from Tannery Effluent and Its Potential Role in Cr (VI) Remediation.

An indigenous chromate-resistant bacterial strain isolated from tannery effluent was identified based on morphological, biochemical, and 16S rRNA gene sequencing, as Enterobacter cloacae UT25. It was found to resist heavy metal ions such as Cr (VI), Pb (II), Cu (II), Co (II), Ni (II), Hg (II), and Zn (II) and antibiotics. The strain was able to remove 89 and 86% chromate, after 24 h of incubation in a Luria-Bertani (LB) medium at an initial Cr (VI) concentration of 1000 and 1500 µg/ml, respectively. Minimum inhibitory concentration (MIC) was observed for chromate to be 80,000 and 1850 µg/ml, after 48 h of incubation in LB and acetate minimal media (AMM), respectively. Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM) analysis showed discrete cells with intact and smooth cell walls and homogenous cytoplasm in the absence of metal stress, whereas chromate stress caused cell lysis and reduction in size, which was a characteristic response to Cr (VI) toxicity. Energy Dispersive X-Ray Spectroscopy (EDX) confirmed the adsorption of oxyanions to the cell wall which was one of the Cr (VI) removal mechanisms by the bacterium. Atomic Force Microscopy (AFM) micrographs of chromate-untreated and treated cells revealed Root Mean Square roughness (Rq) values of 16.25 and 11.26 nm, respectively, indicating less roughness in the presence of stress. The partial gene sequence of class 1 integrons (intI1) of strain UT25 showed 94% homology with intI1 gene of strain Enterobacter hormaechei strain ECC59 plasmid pECC59-1. The present analysis highlighted the potential of E. cloacae UT25 as a promissory bacterium that could be applied in removing chromate from polluted environments.

In vitro anticancer activities of Withania coagulans against HeLa, MCF-7, RD, RG2, and INS-1 cancer cells and phytochemical analysis.

BACKGROUND: The Pakistani Salt Range has a rich floral diversity including Withania coagulans from the Solanaceae family. METHODS: The crude methanolic extracts of the root, leaf, leaf stalk, and fruit of this plant were screened for their cytotoxic activity against human (HeLa, MCF-7, RD) and rat (RG2 and INS-1) cancer cell lines at 20 µg/mL and compared to methotrexate. The IC50 values indicated that leaf stalk and fruit extracts exert an 80% or higher cytotoxic activity against all cell lines at 24 hours. RESULTS: The leaf stalk extract showed the highest cytotoxic efficacy against all tested cell lines, with IC50 values ranging from 0.96 ± 0.01 µg/mL to 4.73 ± 0.05 µg/mL followed by the fruit extract with IC50 values of 0.69 ± 0.01-6.69 ± 0.06 µg/mL after 48-72 hours incubation. The leaf stalk and seed extracts were analyzed for polyphenols and flavonoids using RP-HPLC. The total flavonoid content (TFC) was calculated for all tested samples, and the highest TFC was recorded for the root extract (394.34 ± 1.26 µg/g). The total phenolic content (TPC) was found in the seed extract (307.86 ± 9.42 µg/g) of W. coagulans. The highest contents of myricetin (358.46 ± 2.91 µg/g) were noted in the leaf extract, and highest quercetin was recorded in the seed extract (21.43 ± 0.13 µg/g). The highest gallic acid concentration (83.62 ± 0.71 µg/g) was recorded in leaf stalk extract and p-hydroxybenzoic acid in the seed extract (157.46 ± 1.43 µg/g). CONCLUSION: The present study gives a scientific insight and comparative analysis of various plant parts in this medicinally important plant species from the Salt Range of Pakistan against both human and rat cancer cells.