Silver nanoparticles synthesis from Bacillus sp KFU36 and its anticancer effect in breast cancer MCF-7 cells via induction of apoptotic mechanism.

Biological synthesis of nanoparticles is a growing research trend because it has numerous applications in pharmaceutics and biomedicine. The aim of this study was to obtain silver nanoparticles (AgNPs) from Bacillus sp. KFU36, a marine strain, and to assess its anticancer activity. The supernatant of Bacillus sp. KFU36 was supplemented with silver nitrate and the nanoparticles obtained were characterized spectrophotometrically and microscopically. A band of surface plasmon resonance was appeared at 430 nm, as revealed by UV-vis spectrophotometry. X-ray diffraction spectrum and Energy Dispersive Spectroscopy confirmed the crystalline and metallic structure of the AgNPs, respectively. Scanning electron microscopy revealed that the shape of the synthesized AgNPs were spherical and the size extended between 5 and 15 nm. The AgNPs were investigated for their potential anticancer effects on the cell viability, migration and apoptosis using MTT and wound-healing assays, and flow cytometry, respectively. The cytotoxic effects of these nanoparticles were evidenced by the decreasing the cell viability (as 15% at 50 µg/ml), cell density, adhesion capacity and losing the normal shape and size, and inducing the apoptosis on MCF-7 by 61% at 50 µg/ml. These findings confirm that the synthesized AgNPs exhibited superior anticancer activities and therefore could be exploited as a promising, cost-effective, and environmentally benign strategy in treating this disease in future.

Effect of citric acid and vermi-wash on growth and metal accumulation of Sorghum bicolor cultivated in lead and nickel contaminated soil.

The aim of the present study is to assess the influence of vermi-wash (VW) and citric acid (CA) on Sorghum bicolor growth and phytoaccumulation of lead (Pb) and nickel (Ni) contaminated soil. The biomass of the S. bicolor has been enhanced by the addition of VW (24 and 26%) and CA (11 and 9%) in Pb and Ni contaminated soil, respectively. The VW treatment showed enhanced shoot and root lengths and chlorophyll concentrations compared to CA. The shoot anatomic structure showed an accumulation of Pb and Ni were positively impacted by the amendment of VW and CA. In addition, VW treatment showed enhanced antioxidant enzymes activity (140, 125 and 152 U/mg of CAT, SOD and POD). Further, the plants grown in Pb contaminated soil treated with VW showed enhanced Rubisco activity of 1.49 U/ml, whereas, CA treatment showed 1.23 U/ml of Rubisco. It has been observed that the VW showed as a potential chelator as well as plant beneficial formulation for the enhanced phyto-remediation of Pb and Ni.

Polyphasic characterization of Delftia acidovorans ESM-1, a facultative methylotrophic bacterium isolated from rhizosphere of Eruca sativa.

In this study, one bacterial strain, ESM-1, was isolated from rhizosphere of Eruca sativa, growing in Al Hofouf, Saudia Arabia, after enrichment with methanol as a sole carbon and energy source in a batch culture. ESM-1 was characterized by a polyphasic approach. The strain was identified as Delftia acidovorans at similarity level of 99.9% of the 16S rRNA gene sequences. Results of the Biolog Gen III MicroPlate test system showed that strain ESM-1 reacted positively to 47 (50%) including the one-carbon compound formic acid, and partially positive to 6 (∼6.4%) out of the 94 different the traits examined. The total cellular fatty acids composition of the strain ESM-1 was (C16:1ω7c/C16:1ω6c) and C16:0) and matched that of Delftia acidovorans at a similarity index of 0.9, providing a robustness to the ESM-1 identification. Furthermore, ESM-1 displayed a complex polar lipid profile consisting of phosphatidylethanolamine, phosphatidylglycerol, glycolipid, aminolipid, in addition to uncharacterized lipids. The DNA G+C content of the strain was 66.6 mol%. Phylogenetic analyses based on 16S rRNA gene sequences showed that the strain ESM1-1 was clearly clustered within the Delftia clade and constructed a monophyletic subcluster with Delftia acidovorans NBRC14950. The results addressed that ESM-1 is a facultative methylotrophic bacterium indigenous to Al Hofouf region and opens the door for potential biotechnological applications (e.g., bioremediation) of this strain, in future. Additionally, these findings assure that the total cellular fatty acid analysis and 16S rRNA gene are reliable tool for bacterial characterization and identification.

First isolation and characterization of the pathogenic Aeromonas veronii bv. veronii associated with ulcerative syndrome in the indigenous Pelophylax ridibundus of Al-Ahsaa, Saudi Arabia.

Virulent microbial pathogen infections are the main cause for amphibian decline worldwide. In the present study, a bacterial strain named RDL-2, which was isolated from the skin of infected Pelophylax ridibundus larvae, was cultured and then phenotypically and biochemically characterized using scanning electron microscopic observations and the API20E strip and Biolog Gen III MicroPlate system. The 16S rRNA gene sequence of this strain was also obtained and used in strain identification and phylogenetic analysis. Healthy P. ridibundus larvae were challenged with RDL-2 and monitored to determine clinical signs consistent with the disease. Strain RDL-2 was identified as Aeromonas veronii based on its phenotypic and biochemical characteristics and on 16S rRNA gene sequence and phylogenetic analysis: RDL-2 was gram-negative, rod-shaped, and reacted positively for 69 (73%) of the 94 traits analysed; its 16S rRNA gene sequence displayed the highest homology to that of A. veronii bv. veronii (99.9%). Koch's postulates were fulfilled confirming that A. veronii is the causal agent of ulcerative syndrome. Thus, this study is the first to report A. veronii as a marsh frog pathogen in the Al-Ahsaa region. The aetiology of A. veronii as a potential poikilothermic pathogen shown here will expedite the development of diagnostic tests and methods for eradicating ulcerative syndrome.

Description of a methanotrophic strain BOH1, isolated from Al-Bohyriya well, Al-Ahsa City, Saudi Arabia.

Methanotrophic bacteria have a unique ability to utilize methane as their carbon and energy sources. Therefore, methanotrophs play a key role in suppressing methane emissions from different ecosystems and hence in alleviating the global climate change. Despite methanotrophs having many ecological, economical and biotechnological applications, little is known about this group of bacteria in Al-Ahsa. Therefore, the main objective of the current work was to expand our understanding of methane oxidizing bacteria in Al-Ahsa region. The specific aim was to describe a methanotrophic strain isolated from Al-Bohyriya well, Al-Ahsa using phenotypic, genotypic (such as 16S rRNA and pmoA gene sequencing) and phylogenetic characterization. The results indicated that the strain belongs to the genus Methylomonas that belongs to Gammaproteobacteria as revealed by the comparative sequence analysis of the 16S rRNA and pmoA genes. There is a general agreement in the profile of the phylogenetic trees based on the sequences of 16srRNA and pmoA genes of the strain BOH1 indicating that both genes are efficient taxonomic marker in methanotrophic phylogeny. The strain possesses the particulate but not the soluble methane monooxygenase as a key enzyme for methane metabolism. Further investigation such as DNA:DNA hybridization is needed to assign the strain as a novel species of the genus Methyomonas and this will open the door to explore the talents of the strain for its potential role in alleviating global warming and biotechnological applications in Saudi Arabia such as bioremediation of toxic by-products released in oil industry. In addition, the strain enhances our knowledge of methanotrophic bacteria and their adaptation to desert ecosystems.

Characterization of the plant growth promoting bacterium, Enterobacter cloacae MSR1, isolated from roots of non-nodulating Medicago sativa.

The aim of the present study was to characterize the endophytic bacterial strain designated MSR1 that was isolated from inside the non-nodulating roots of Medicago sativa after surface-sterilization. MSR1 was identified as Enterobacter cloacae using both 16S rDNA gene sequence analysis and API20E biochemical identification system (Biomerieux, France). Furthermore, this bacterium was characterized using API50CH kit (Biomerieux, France) and tested for antibacterial activities against some food borne pathogens. The results showed that E. cloacae consumed certain carbohydrates such as glycerol, d-xylose, d-maltose and esculin melibiose as a sole carbon source and certain amino acids such as arginine, tryptophan ornithine as nitrogen source. Furthermore, MSR1 possessed multiple plant-growth promoting characteristics; phosphate solubility, production of phytohormones acetoin and bioactive compounds. Inoculation of Pisum sativum with MSR1 significantly improved the growth parameters (the length and dry weight) of this economically important grain legume compared to the non-treated plants. To our knowledge, this is the first report addressing E. cloacae which exist in roots of alfalfa growing in Al-Ahsaa region. The results confirmed that E. cloacae exhibited traits for plant growth promoting and could be developed as an eco-friendly biofertilizer for P. sativum and probably for other important plant species in future.