Optimization of Bacillus subtilis growth parameters for biosynthesis of silver nanoparticles by using response surface methodology.

Silver nanoparticles (AgNPs) are among the most widely biosynthesized and used nanomaterials. They have different unique properties and a wide range of applications. This study is concerned with optimization of the growth conditions of Bacillus subtilis NRC1 for the biosynthesis of AgNPs using two designs of response surface methodology (RSM) statistical analysis. The data obtained from Plackett-Burman design (PBD) followed by central composite design (CCD), showed a good agreement between the experimental and predicted values of AgNPs biosynthesis. The optimum conditions were 0.7% (w/v) casein hydrolysate, 5% dextrin (w/v), pH 7.5 and 57 × 106 CFU/ml inoculum size. The model was highly valid and could be applied with a confidence factor of 99.47%. Minimal inhibitory concentration (MIC) of these AgNPs synthesized using the extracellular filtrate after growth of Bacillus subtilis NRC1 in the optimized medium was found to be 41-43µg/ml for all tested microorganisms with exception of Pseudomonas aeruginosa where MIC was 169 µg/ml.

Optimization of Bacillus subtilis NRC1 growth conditions using response surface methodology for sustainable biosynthesis of gold nanoparticles.

Gold nanoparticles (AuNPs) have different unique properties and a wide range of applications in different fields. Thereby, there is a growing urgency for the production of AuNPs using a safe and an economic method. In this study, optimization of fermentation conditions by Bacillus subtilis NRC1 for extracellular AuNPs synthesis using response surface methodology was achieved. The data obtained from Plackett-Burman design followed by Box-Behnken design indicated the accuracy and reliability of the model and it could be used to navigate the design space with a reasonable accuracy. Numerical optimization of Bacillus subtilis NRC1 active extracellular filtrate production, showed the optimum conditions of 0.74% (w/v) casein hydrolysate, 3.99% (w/v) dextrin, 47 × 106 CFU/ml inoculum size at pH 7.76 and 25 [Formula: see text]C to give the maximum AuNPs biosynthesis. The model was highly valid and the obtained data had a confidence factor of 98.48%. Statistical optimization resulted in a 2.6-fold increase in AuNPs production compared with that of the non-optimized medium.

Biosynthesis of silver nanoparticles using isolated Bacillus subtilis: characterization, antimicrobial activity, cytotoxicity, and their performance as antimicrobial agent for textile materials.

Silver nanoparticles (AgNPs) have unique properties and a large range of applications. Biosynthesis of stable AgNPs using the extracellular filtrate of Bacillus subtilis was proved by the characteristic surface plasmon resonance at about 420-430 nm. They were polycrystalline with spherical, hexagonal, and irregular shapes and they were negatively charged (-40 mV) with an average diameter of 20 nm. FTIR spectrum confirmed the presence of protein molecules coating AgNPs. The optimum conditions for the synthesis of tested AgNPs were 1:6 filtrate dilution, 1 mM AgNO3, pH 7, 30 °C , 48 h contact time under static and illuminating conditions. The synthesized AgNPs showed antibacterial activities against Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa, Bacillus cereus, and Salmonella typhi, antifungal activity against Candida albicans and antiviral activity against rotavirus. Also, they showed potent cytotoxic effects on lung and hepatic carcinoma human cell lines. Meanwhile, the acute toxicity study against mice showed no significant changes in hematological, biochemical, and histological parameters of AgNPs treated mice. They also showed mild hepatoprotective effect in thioacetamide (TAA) - induced hepatic fibrosis in rats. AgNPs treated textiles fabrics showed high antimicrobial activities against different pathogenic microorganisms as well as UV protection adequacy.

CD11c+ and CD123+ dendritic cell subsets in peripheral blood of lung cancer patients.

Dendritic cells (DCs) play a central role in antitumor immune responses. Recent studies however have emphasized an immunosuppressive tumor influence on DCs in various types of cancer. We evaluated the percentages of myeloid and plasmacytoid related DCs in non-small cell lung cancer (NSCLC) and small cell lung cancer (SCLC). Myeloid CD11c+ DCs (mDC) and plasmacytoid CD123+ DCs (pDC) cells were assessed by Flowcytometry in peripheral blood of twenty untreated lung cancer patients (13 NSCLC and 7 SCLC) and 15 healthy subjects. Lower percentages of pDCs and mDCs were found in patient with NSCLC and SCLC as compared to controls, with significant value only between NSCLC patients and controls (P= 0.001and P=0.000 respectively). The percentages of pDCs and mDCs subsets were significantly lower in patient with SCLC than NSCLC (P=0.013 and P=0.005 for pDCs and mDCs respectively). Our results suggest that NSCLC and SCLC might hamper the maturation of DCs, thus escaping an efficient immune response.

Interleukin 16 (IL-16) in asthma and allergic rhinitis. A comparison between upper and lower airways.

Asthma is a chronic inflammatory disease of bronchial mucosa, in which mast cells, eosinophils and activated T cells are of considerable importance. The increased chemotactic activity for T cells in patients with asthma is mainly attributable to IL-16. A strong association between asthma and allergic rhinitis exists from a clinical and epidemiologic standpoint of view. Although it is clear that the condition of the upper airways has impact on the lower airway physiology, the precise mechanisms underlying this relation are far from being resolved. This work was assessed the role of interleukin 16 (IL-16) in bronchoalveolar lavage (BAL) fluid in both diseases using quantitative sandwich enzyme immuno-assay, and the effect on ventilatory function. The results showed abnormally increased levels of IL-16 (294.4 +/- 15.24 pg/ml), serum eosinophils with absolute count (510.0 +/- 93.57, P>0.05), and total serum IgE (287.9 +/- 61.22 IU/ml) using ELFA in patients of combined asthma and rhinitis, than in each of them alone. There was reduction in FEV1 (forced expiratory volume in the first second) in the same group (81.6 +/- 2.01%). There was a negative correlation between BAL IL-16 and FEV1. In conclusion IL-16 may be considered as a marker of severity of airway inflammation.