Background
Rosmarinus officinalis L. from Tunisia, popularly known as rosemary, is of a considerable importance for its medicinal uses and aromatic value. The aim of this study was to examine the chemical composition of Rosmarinus officinalis essential oil (ROEO) and to evaluate its antibiofilm activity on biofilm-forming bacterium and its anticancer activity on cancer cell lines.MethodsThe chemical composition of Rosmarinus officinalis essential oil (ROEO) was analyzed by GC-MS and its antibacterial activity was evaluated by micro-dilution method. The antibofilm activity of ROEO was evaluated using the crystal violet test and the cytotoxicity activity was determined by the MTT assay.ResultsIn this research, thirty-six compounds were identified in ROEO using GC-MS analyses. The main components were 1,8-cineole (23.56%), camphene (12.78%), camphor (12.55%) and β-pinene (12.3%). The antibacterial activity of ROEO was evaluated by micro-dilution method. The oil exhibited inhibition and bactericidal effect against two strains: Staphylococcus aureus ATCC 9144 and Staphylococcus epidermidis S61. It was found that the minimum inhibitory concentration (MIC) obtained for S. aureus and S. epidermidis ranged from 1.25 to 2.5 and from 0.312 to 0.625 μl ml−1, respectively and the minimum bactericidal concentration (MBC) were in the order of 5 and 2.5 μl ml−1, respectively. Furthermore, this oil showed a S. epidermidis biofilm inhibition more than 57% at a concentration of 25 μl ml−1. The eradication of 67% of the established biofilm was observed at a concentration of 50 μl ml−1 of ROEO, whereas the dose of 25 μl ml−1 removed only 38% of preformed biofilm. ROEO strongly inhibited the proliferation of Hela and MCF-7 cells with IC50 values of 0.011 and 0.253 μl ml−1, respectively.ConclusionOur results demonstrate that ROEO could have a potential role in the treatment of diseases related to infection by microorganisms or proliferation of cancer cells.
The mitogen-activated protein kinase (MAPK) signaling pathway plays key roles in the transmission of proliferative signals in normal and dysregulated cells. Nevertheless, some studies have shown that activation of the extracellular regulated kinases 1/2 (Erk1/2) is involved in apoptosis. In this study, we evaluate the effect of two fertilizing drugs, clomiphene citrate and estradiol, on the activation of Erk1/2 and the viability of two breast cancer cell lines, MCF-7 (hormone dependent) and BT20 (hormone independent).We show that both drugs induce Erk1/2 phosphorylation in MCF-7 and BT20 cells despite their opposite effect on cell viability. In fact, clomiphene citrate is significantly proapoptotic while estradiol promotes cell proliferation. The fact that phospho-Erk1/2 is a common element to both mechanisms suggests that specific factors deciding between proliferation and apoptosis must be operative downstream of this signaling pathway.
Multi-contaminated industrial wastewaters pose serious environmental risks due to high toxicity and non-biodegradability. The work reported here evaluated the ability of Pseudomonas aeruginosa strain Gb30 isolated from desert soil to simultaneously remove cadmium (Cd) and Reactive Black 5 (RB5), both common contaminants in various industrial effluents. The strain was able to grow normally and decolorize 50 mg L -1 RB5 within 24 h of incubation in the presence of 0.629 m mol L -1 of Cd 2+ . In order to evaluate strain performance in RB5 detoxification, a cytotoxicity test using Human Embryonic Kidney cells (HEK293) was used. Cadmium removal from culture media was determined using atomic adsorption. Even in presence of (0.115 + 0.157 + 0.401 +0.381) m mol L -1 , respectively, of Cr 6+ , Cd 2+ , Cu 2+ and Zn 2+ in the growth medium, strain Gb30 successfully removed 35% of RB5 and 44%, 36%, 59% and 97%, respectively, of introduced Zn 2+ , Cu 2+ , Cr 6+ and Cd 2+ , simultaneously. In order to understand the mechanism of Cd removal used by P. aeruginosa strain Gb30, biosorption and bioaccumulation abilities were examined. The strain was preferentially biosorbing Cd on the cell surface, as opposed to intracellular bioaccumulation. Microscopic investigations using AFM, SEM and FTIR analysis of the bacterial biomass confirmed the presence of various structural features, which enabled the strain to interact with metal ions. The study suggests that Pseudomonas aeruginosa Gb30 is a potential candidate for bioremediation of textile effluents in the presence of complex dye-metal contamination.
The epidermal growth factor receptor (EGFR) harbors a calmodulin (CaM)‐binding domain (CaM‐BD) and a CaM‐like domain (CaM‐LD) upstream and downstream, respectively, of the tyrosine kinase (TK) domain. We demonstrate in this paper that deletion of the positively charged CaM‐BD (EGFR/CaM‐BD∆) inactivated the TK activity of the receptor. Moreover, deletion of the negatively charged CaM‐LD (EGFR/CaM‐LD∆), leaving a single negative residue (glutamate), reduced the activity of the receptor. In contrast, substituting the CaM‐LD with a histidine/valine‐rich peptide (EGFR/InvCaM‐LD) caused full inactivation. We also demonstrated using confocal microscopy and flow cytometry that the chimera EGFR‐green fluorescent protein (GFP)/CaM‐BD∆, the EGFR/CaM‐LD∆, and EGFR/InvCaM‐LD mutants all bind tetramethylrhodamine‐labelled EGF. These EGFR mutants were localized at the plasma membrane as the wild‐type receptor does. However, only the EGFR/CaM‐LD∆ and EGFR/InvCaM‐LD mutants appear to undergo ligand‐dependent internalization, while the EGFR‐GFP/CaM‐BD∆ mutant seems to be deficient in this regard. The obtained results and in silico modelling studies of the asymmetric structure of the EGFR kinase dimer support a role of a CaM‐BD/CaM‐LD electrostatic interaction in the allosteric activation of the EGFR TK.
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