In vitro study of leishmanicidal activity of biogenic selenium nanoparticles against Iranian isolate of sensitive and glucantime-resistant leishmania tropica

Sensitive and glucantime [MA] resistance Leishmania tropica are referred to those isolates, which are responsive, or non-responsive to one or two full courses of treatment by MA systematically and/or intra-lesionally, respectively. In this study, we evaluated the antileishmanial activity of biogenic selenium nanoparticles [Se NPs] alone and in combination with MA against sensitive and glucantimeresistant L. tropica on in vitro model. The Se NPs were synthesized by employing the Bacillus sp. MSh-1. The antileishmanial effects of Se NPs alone and in combination with MA on promastigote and amastigote stages of sensitive and glucantime-resistant L. tropica strains have been investigated using a colorimetric MTT assay and in a macrophage model. In addition hemolytic activity in type O+ human red blood cells and infectivity rate of the promastigotes before and after treatment with the Se NPs was evaluated. In the promastigote stage, various concentrations of Se NPs significantly inhibited [P<0.05] the growth of promastigotes of both strains in a dose-dependent manner. Similarly, Se NPs especially in combination with MA significantly reduced the mean number of amastigotes of both strains in each macrophage. Se NPs showed no hemolytic effect on human RBCs at low concentrations. Moreover, infection rate of macrophages by promastigotes significantly [P<0.05] was reduced when promastigotes pre-treated with Se NPs. The findings of this study suggest a first step in the search of Se NPs as a new antileishmanial agent. Further experiments are needed to investigate antileishmanial effects of biogenic Se NPs on L. tropica using a clinical setting

Antimicrobial activity of bacillus sp. strain fas isolated from soil

During screening for antibiotic producing microorganisms from environmental soil samples, the supernatant of a bacterial isolate was found to have antibacterial and antifungal activity on the standard indicator species. The standard cylinder-plate method was used to determine the inhibitory effect of the crude supernatant of each isolate on 6 bacterial and 3 fungal standard strains by measuring the diameter of inhibition zone. The highest inhibition zone on Aspergillus niger belonged to culture broth of isolate FASi by 25 mm, and this isolate was the most efficient microorganism to inhibit standard bacterial and fungal species. Based on morphological and biochemical properties as well as 16S rDNA gene analysis, the selected isolate [isolate FASi] belonged to Bacillus gems. Investigation on the ability of different culture media for antibiotic production led to select Luria-Bertani media for further studies. Treatment of the culture broth of the isolate FAS[1] using typical protease did't decease the antimicrobial activity of the supernatant. After extracting of culture broth of the selected isolate by ethyl acetate as an organic solvent, the inhibitory effect was mainly increased. More investigation was done by bioautography method where the ethyl acetate fraction of the broth culture was separated on TLC by chloroformimethanol, 60:40 as mobile phase and R[f] were calculated for inhibition spots

Cytotoxic activities of silver nanoparticles and silver ions in parent and tamoxifen-resistant T47D human breast cancer cells and their combination effects with tamoxifen against resistant cells

Studies on biomedical applications of nanoparticles are growing with a rapid pace. In medicine, nanoparticles may be the solution for multi-drug-resistance which is still a major drawback in chemotherapy of cancer. In the present study, we investigated the potential cytotoxic effect of silver nanoparticles [Ag NPs] and silver ions [Ag[+]] in both parent and tamoxifen-resistant T47D cells in presence and absence of tamoxifen. Ag NPs were synthesized [< 28 nm] and MTT assay was carried out. The associated IC[50] values were found to be: 6.31 micro g/ml for Ag NPs/parent cells, 37.06 micro g/ml for Ag NPs/tamoxifen-resistant cells, 33.06 micro g/ml for Ag[+]/parent cells and 10.10 micro g/ml for Ag[+]/resistant cells. As a separate experiment, the effect of subinhibitory concentrations of Ag NPs and Ag[+] on the proliferation of tamoxifen-resistant cells was evaluated at non-toxic concentrations of tamoxifen. Our results suggested that in noncytotoxic concentrations of silver nanomaterials and tamoxifen, the combinations of Ag[+]-tamoxifen and Ag NPs-tamoxifen are still cytotoxic. This finding may be of great potential benefit in chemotherapy of breast cancer; since much lower doses of tamoxifen may be needed to produce the same cytotoxic effect and side effects will be reduced