Samira Salari

Plant-mediated green synthesis of silver nanoparticles using Trifolium resupinatum seed exudate and their antifungal efficacy on Neofusicoccum parvum and Rhizoctonia solani.

In recent years, biosynthesis and the utilisation of silver nanoparticles (AgNPs) has become an interesting subject. In this study, the authors investigated the biosynthesis of AgNPs using Trifolium resupinatum (Persian clover) seed exudates. The characterisation of AgNPs were analysed using ultraviolet-visible spectroscopy, X-ray diffraction (XRD), transmission electron microscopy (TEM) and Fourier transform infra-red spectroscopy. Also, antifungal efficacy of biogenic AgNPs against two important plant-pathogenic fungi (Rhizoctonia solani and Neofusicoccum Parvum) in vitro condition was evaluated. The XRD analysis showed that the AgNPs are crystalline in nature and have face-centred cubic geometry. TEM images revealed the spherical shape of the AgNPs with an average size of 17 nm. The synthesised AgNPs were formed at room temperature and kept stable for 4 months. The maximum distributions of the synthesised AgNPs were seen to range in size from 5 to 10 nm. The highest inhibition effect was observed against R. solani at 40 ppm concentration of AgNPs (94.1%) followed by N. parvum (84%). The results showed that the antifungal activity of AgNPs was dependent on the amounts of AgNPs. In conclusion, the AgNPs obtained from T. resupinatum seed exudate exhibit good antifungal activity against the pathogenic fungi R. solani and N. Parvum.

Evaluation of Antifungal Effect of Silver Nanoparticles Against Microsporum canis, Trichophyton mentagrophytes and Microsporum gypseum

BACKGROUND Dermatophytosis is the common cutaneous infections in humans and animals, which is caused by the keratinophylic fungus called dermatophytes. In recent years, drugs resistance in pathogenic fungi, including dermatophyte strains to the current antifungals have been increased. OBJECTIVES The aim of this study was to evaluate the antifungal efficacy of AgNPs against Microsporum canis, Trichophyton mentagrophytes , and Microsporum gypseum. MATERIALS AND METHODS The antifungal susceptibility of nanosilver particles compared with griseofulvin (GR). Its efficacy was investigated against three strains of dermatophytes by both agar dilution and broth microdilution test (BMD). RESULTS The average minimum inhibitory concentration (MIC) AgNPs on M. canis, T. mentagrophytes and M. gypseum were 200, 180 and 170 μg.mL-1, respectively. Whereas these strains showed MIC of 25, 100 and 50 μg.mL-1 for GR. CONCLUSIONS Our finding indicated that the AgNPs was less active than GR but it had anti-dermatophytic effect.

The role of GlcNAc-PI-de-N-acetylase gene by gene knockout through homologous recombination and its consequences on survival, growth and infectivity of Leishmania major in in vitro and in vivo conditions

At present, there are no efficacious vaccines or effective drugs against leishmaniasis; therefore new and innovative control methods are urgently required. One way to achieve this important goal is through using reverse genetic engineering to evaluate important enzymes, proteins and macromolecules. One of the most important enzymes for Glycosylphosphatidylinositol (GPI) biosynthetic pathways is GlcNAc-PI-de-N-acetylase (GPI12). The molecular constructs were cloned in Escherichia coli strain Top 10 and confirmed by molecular methods and were transfected by electroporation into Leishmania major. We demonstrated that two alleles of the GPI12 gene in L. major were successfully removed and enabling the generation of a null mutant, which supports the idea that GPI12 is not an essential gene for the growth and survival of Leishmania and the homozygous knockouts of Leishmania are able to survive. We were able to produce a mutant parasite that caused no damaged to the host. Further investigations are essential to check the safety profile in laboratory animals.

Onychomycosis due to dermatophytes species in Iran: Prevalence rates, causative agents, predisposing factors and diagnosis based on microscopic morphometric findings

OBJECTIVE Onychomycosis (OM) or fungal nail infection is one of the most common fungal infections, which is increasingly prevalent. OM is caused by dermatophytes spp, yeasts and non-dermatophyte moulds (NDMs). The purpose of this study was to identify and determine the prevalence rates, predisposing factors and causative agents of OM using clinical symptoms and microscopic morphometric findings. MATERIALS AND METHODS In the present study, 180 patients suspected of OM were evaluated by direct microscopy using KOH 20%, culturing in Mycosel and Sabouraud dextrose agar media and Olysia software for identifying the causative fungi of OM. RESULTS From 180 referred patients, 118 (65.56%) had OM, of whom 79 (66.94%) were positive for infection with dermatophytes spp. Of the 79 cases, the commonest age group was 61-70 years (21%) with males being 46 (58.23%) and females being 33 (41.77%). Both the fingernail and toenail infections were most prevalent in male patients. Sex, diabetes and age above 60 years were significant predisposing factors for OM development. DLSO was observed as the only clinical pattern of OM and T. rubrum was the commonest dermatophyte isolate (49.34%). CONCLUSION This study showed that T. rubrum was the most common dermatophyte agent of OM in Iran.

Evaluation of biofilm formation ability in different Candida strains and anti-biofilm effects of Fe 3 O 4 -NPs compared with Fluconazole: an in vitro study

OBJECTIVE Biofilm formation ability is one of the major virulence factors contributing to the pathogenesis of Candida species. Biofilms produced by Candida spp. cause complicated treatments and contribute to increasing unpleasant mortality rates. Nanoparticles of Fe3O4 (Fe3O4-NPs) are considered due to their magnetic and biochemical properties, as well as their low costs. The purpose of present study was to determine biofilm formation ability in different Candida strains and evaluation of anti-biofilm effect of Fe3O4-NPs compared with FLC. MATERIALS AND METHODS In this study, the biofilm-forming ability of Candida strains and the inhibitory effects of Fe3O4-NPs on Candida strains biofilms compared with FLC were measured by MTT assay. RESULTS Our finding showed that the biofilm formation ability of C. lusitaniae was significantly higher than other tested Candida strains. However, all the studied Candida strains produced high degree of biofilms. The biofilm formation in different Candida strains was inhibited at concentrations ≥1000μg/mL to ≥4000μg/mL for Fe3O4-NPs and ≥512μg/mL to ≥2048μg/mL for FLC. After exposure to various concentrations of Fe3O4-NPs, biofilm formation reduction in C. albicans and C. parapsilosis were more than FLC. Although, this reduction was not significant. A significant reduction (P<0.05) was observed in biofilm formation in presence of FLC compared with Fe3O4-NPs in C. krusei, C. tropicalis, and C. lusitaniae. The inhibitory effects of Fe3O4-NPs and FLC on biofilm formation of C. glabrata were approximately equal. CONCLUSION In accordance with the findings, the biofilm reduction effect of FLC for C. krusei, C. tropicalis, and C. lusitaniae were statistically higher than Fe3O4-NPs.

Effect of biogenic selenium nanoparticles on ERG11 and CDR1 gene expression in both fluconazole-resistant and -susceptible Candida albicans isolates

Background and Purpose: Candida albicans is the most common Candida species (sp.) isolated from fungal infections. Azole resistance in Candida species has been considerably increased in the last decades. Given the toxicity of the antimicrobial drugs, resistance to antifungal agents, and drug interactions, the identification of new antifungal agents seems essential. In this study, we assessed the antifungal effects of biogenic selenium nanoparticles on C. albicans and determined the expression of ERG11 and CDR1 genes. Materials and Methods: Selenium nanoparticles were synthesized with Bacillus sp. MSH-1. The ultrastructure of selenium nanoparticles was evaluated with a transmission electron microscope. The antifungal susceptibility test was performed according to the modified Clinical and Laboratory Standards Institute M27-A3 standard protocol. The expression levels of the CDR1 and ERG11 genes were analyzed using the quantitative real-time polymerase chain reaction (PCR) assay. Results: The azole-resistant C. albicans and wild type C. albicans strains were inhibited by 100 and 70 µg/mL of selenium nanoparticle concentrations, respectively. The expression of CDR1 and ERG11 genes was significantly down-regulated in these selenium nanoparticle concentrations. Conclusion: As the findings indicated, selenium nanoparticles had an appropriate antifungal activity against fluconazole-resistant and -susceptible C. albicans strains. Accordingly, these nanoparticles reduced the expression of CDR1 and ERG11 genes associated with azole resistance. Further studies are needed to investigate the synergistic effects of selenium nanoparticles using other antifungal drugs.