Evaluation of phenolic profile,antioxidant and anticancer potential of two main representants of Zingiberaceae family against B164A5 murine melanoma cells

Background

Curcuma longa Linnaeus and Zingiber officinale Roscoe are two main representatives of Zingiberaceae family studied for a wide range of therapeutic properties, including: antioxidant, anti-inflammatory, anti-angiogenic, antibacterial, analgesic, immunomodulatory, proapoptotic, anti-human immunodeficiency virus properties and anticancer effects. This study was aimed to analyse the ethanolic extracts of Curcuma rhizome (Curcuma longa Linnaeus) and Zingiber rhizome (Zingiber officinale Roscoe) in terms of polyphenols, antioxidant activity and anti-melanoma potential employing the B164A5 murine melanoma cell line.

Results

In order to evaluate the total content of polyphenols we used Folin-Ciocâlteu method. The antioxidant activity of the two ethanolic extracts was determined by DPPH assay, and for the control of antiproliferative effect it was used MTT proliferation assay, DAPI staining and Annexin-FITC-7AAD double staining test. Results showed increased polyphenols amount and antioxidant activity for Curcuma rhizome ethanolic extract. Moreover, 100 μg/ml of ethanolic plant extract from both vegetal products presented in a different manner an antiproliferative, respectively a proapoptotic effect on the selected cell line.

Conclusions

The study concludes that Curcuma rhizome may be a promising natural source for active compounds against malignant melanoma.     

Nickel(II) complexes of the multihistidine peptide fragments of human prion protein

Nickel(II) complexes of the peptide fragments of human prion protein containing histidyl residues both inside and outside the octarepeat domain have been studied by the combined application of potentiometric, UV-visible and circular dichroism spectroscopic methods. The imidazole-N donor atoms of histidyl residues are the exclusive metal binding sites below pH 7.5, but the formation of stable macrochelates was characteristic only for the peptide HuPrP(76-114) containing four histidyl residues. Yellow colored square planar complexes were obtained above pH 7.5-8 with the cooperative deprotonation of three amide nitrogens in the [N_im,N⁻,N⁻,N⁻] coordination mode. It was found that the peptides can bind as many nickel(II) ions as the number of independent histidyl residues. All data supported that the complex formation processes of nickel(II) are very similar to those of copper(II), but with a significantly reduced stability for nickel(II), which shifts the complex formation reactions into the slightly alkaline pH range. The formation of coordination isomers was characteristic of the mononuclear complexes with a significant preference for the nickel(II) binding at the histidyl sites outside the octarepeat domain. The results obtained for the two-histidine fragments of the protein, HuPrP(91-115), HuPrP(76-114)H85A and HuPrP(84-114)H96A, made it possible to compare the binding ability of the His96 and His111 sites. These data reveal a significant difference in the nickel(II) and copper(II) binding sites of the peptides: His96 was found to predominate almost completely for nickel(II) ions, while the opposite order, but with comparable concentrations, was reported for copper(II).     

Determination and validation of a simple high-performance liquid chromatographic method for simultaneous assay of iprodione and vinclozolin in human urine

A method based on solid-phase extraction (SPE) and high-performance liquid chromatography (HPLC) was developed for the simultaneous determination of 3-(3,5-diclorophenyl)-5-ethenyl-5-methyl-2,4-oxazolidinedione (vinclozolin) and 3-(3,5-diclorophenyl)-N-(1-methylethyl)-2,4-dioxo-1-imidazolidinecarboxamide (iprodione) in human urine. Urine samples containing vinclozolin and iprodione were collected by solid phase extraction using C(18) cartridges. The chromatographic separation was achieved on a Spherisorb ODS2 (250 mm x 4.6 mm, 5 microm) column with an isocratic mobile phase of acetonitrile-water (60:40, v/v). Detection was UV absorbance at 220 nm. The calibration graphs were linear from 30 to 1000 ng/mL for the two fungicides. Intra- and inter-day R.S.D. did not exceed 2.9%. The quantitation limit was 50 ng/mL for vinclozolin and 30 ng/mL for iprodione, respectively.     

Mechanistic insights into the role of Hop2–Mnd1 in meiotic homologous DNA pairing

The Hop2–Mnd1 complex functions with the DMC1 recombinase in meiotic recombination. Hop2–Mnd1 stabilizes the DMC1-single-stranded DNA (ssDNA) filament and promotes the capture of the double-stranded DNA partner by the recombinase filament to assemble the synaptic complex. Herein, we define the action mechanism of Hop2–Mnd1 in DMC1-mediated recombination. Small angle X-ray scattering analysis and electron microscopy reveal that the heterodimeric Hop2–Mnd1 is a V-shaped molecule. We show that the protein complex harbors three distinct DNA binding sites, and determine their functional relevance. Specifically, the N-terminal double-stranded DNA binding functions of Hop2 and Mnd1 co-operate to mediate synaptic complex assembly, whereas ssDNA binding by the Hop2 C-terminus helps stabilize the DMC1-ssDNA filament. A model of the Hop2-Mnd1-DMC1-ssDNA ensemble is proposed to explain how it mediates homologous DNA pairing in meiotic recombination.     

Sporosarcina pasteurii can be used to print a layer of calcium carbonate

When using microbiologically induced calcium carbonate precipitation (MICP) to produce calcium carbonate crystals in the cavities between mineral particles to consolidate them, the inhomogeneous distribution of the precipitated calcium carbonate poses a problem for the production of construction materials with consistent parameters. Various approaches have been investigated in the literature to increase the homogeneity of consolidated samples. One approach can be the targeted application of ureolytic organisms by 3D printing. However, to date, this possibility has been little explored in the literature. In this study, the potential to use MICP to print calcium carbonate layers on mineral particles will be investigated. For this purpose, a dispensing unit was modified to apply both a suspension of Sporosarcina pasteurii and a calcination solution containing urea and calcium chloride onto quartz sand. The study showed that after passing through the nozzle, S. pasteurii preserved consistent cell vitality and therefore its potential of MICP. Applying cell suspension and calcination solution through a printing nozzle resulted in a layer of calcium carbonate crystals on quartz sand. This observation demonstrated the proof of concept of printing calcium carbonate by MICP through the nozzle of a dispensing unit. Furthermore, it was shown that cell suspensions of S. pasteurii can be stored at 4°C for a period of 17 days while maintaining its optical density, urease activity and cell vitality and therefore the potential for MICP. This initial concept could be extended in further research to printing three‐dimensional (3D) objects to solve the problem of homogeneity in consolidated mineral particles.     

Citrate-silver nanoparticles and their impact on some environmental beneficial fungi

Colloidal suspensions of silver nanoparticles (AgNPs) with surface modified by capping with citrate ions were synthesized by chemical reduction method. Transmission and Scanning Electron Microscopy as well as darkfield Optical Microscopy provided information on the nanoparticle morphology, with fine symmetrical grains and log-normal fitted size distribution. Small Angle X-ray Scattering method allowed theoretical confirmation of colloidal silver nanoparticle fine granularity, based on measurements in the native fluid sample. UV–Vis spectrophotometry allowed studying the Localized Surface Plasmon Resonance band versus the stability of the citrate-AgNP sample after storage and after UV-C exposure. The colloidal AgNP impact on Phanerochaete chrysosporium environmental microorganisms was studied by specific biochemical investigations. Silver released from the colloidal suspension of AgNPs was supposed to induce changes in some antioxidant enzymes and in some enzymes of Krebs’ cycle. Catalase activity was moderately changed (an increase with over 50%) as well as superoxide dismutase activity, while the diminution of the activities of four dehydrogenases synthesized in the fungus mycelium was emphasized also: a decrease with about 60% for malate dehydrogenase, with over 50% for isocitrate dehydrogenase and succinate dehydrogenase and with about 40% for alpha-ketoglutarate dehydrogenase. These findings suggested the nano-toxicological issues of citrate-AgNPs impact on the environmental beneficial microorganisms.