Electrochemical immunosensor based on carbon nanofibers and gold nanoparticles for detecting anti-Toxoplasma gondii IgG antibodies.

An electrochemical immunosensor based on carbon nanofibers (CNFs) and gold nanoparticles (AuNPs) was developed for detecting anti-Toxoplasma gondii antibodies  (anti-T. gondii) IgG in human serum. CNFs were produced using electrospinning and carbonization processes. Screen-printed carbon electrode (SPCE) surface was modified with CNFs and AuNPs which were electrodeposited onto the CNFs. Then, T. gondii antigen was immobilized onto the AuNPs/CNFs/SPCE. Afterward, anti-T. gondii IgG positive serum samples were coated on the modified electrode and assessed via adding anti-human IgG labeled with horseradish peroxidase (HRP) enzyme. The morphology of SPCE, CNFs, and AuNPs/CNFs/SPCE surface was characterized using field emission scanning electron microscopy (FESEM) equipped with energy dispersive spectroscopy (EDS). Characterization of CNFs was evaluated by Raman spectroscopy and X-ray diffraction (XRD). Electrochemical characterization of the immunosensor was verified using cyclic voltammetry (CV), and electrochemical response of modified electrode for anti-T. gondii IgG was detected via differential pulse voltammetry (DPV). This immunosensor was detected in the range 0-200 U mL-1 with a low detection limit (9 × 10-3 U mL-1). In addition, the proposed immunosensor was exhibited with high selectivity, strong stability, and acceptable reproducibility and repeatability. Furthermore, there was a strong correlation between results obtained via the designed immunosensor and enzyme-linked immunosorbent assay (ELISA) as gold standard. In conclusion, the developed immunosensor is a promising route for rapid and accurate clinical diagnosis of toxoplasmosis.

Induction of Apoptosis by Alcoholic Extract of Combination Verbascum thapsus and Ginger officinale on Iranian Isolate of Trichomonas vaginalis.

BACKGROUND: The protozoan Trichomonas vaginalis is a sexually transmitted disease (STD). Metronidazole is a chosen drug for the treatment. This study evaluated the anti trichomonal activity of alcoholic extracts of combination Verbascum thapsus and Ginger officinale. METHODS: This experimental study was conducted in the Parasitology Laboratory, Kashan University of Medical Sciences, Kashan, Iran in 2015, on 23 women with suspected trichomoniasis referring to Kashan clinical centers. Medium TYI-S-33 was used for culture of three T. vaginalis isolates. Different concentrations (25, 50, 100, 200, 400, 800 µg/ml) of V. thapsus and G. officinale ethanol extract added to Trichomonas trophozoites in 48-well plates and metronidazole considered as positive control and the negative control was TYI-S33 containing Trichomonas trophozoites without any drug. In all of mentioned groups, trophozoites number counted 12, 24, 48 h after culture. Results were analyzed using ANOVA statistical test, to evaluate the toxicity of extract, measured by MTT assay. Induced apoptosis of T. vaginalis after treatment with different concentrations of extract was determined by Flow Cytometry. RESULTS: IC50 of alcoholic extract of combination V. thapsus and G. officinale and metronidazole after 24h was 73.80 µg/ml and 0.0326 µg/ml, respectively. The toxicity percentage of 25-800 µg/ml concentrations of this combination were between 0.2-1.98. In different concentrations of extract (25,50,100,200 and 400 µg/ml) apoptosis percent after 48h was 18.97 to 77.19 and necrosis percent was calculated 1.35, 3.18, 3.10, 1.16 and 4.09, respectively. CONCLUSION: Alcoholic extract of combination V. thapsus and G. officinale induces programmed death in T. vaginalis. Due to no toxicity on macrophages, it can be examined in vivo studies.

In Vitro Susceptibility of Iranian Isolates of Trichomonas vaginalis to Metronidazole.

BACKGROUND: Metronidazole, a 5-nitroimidazole derivative, is the main antitrichomonal agent of choice for treatment of trichomoniasis. Since 1962, some cases of treatment failure with metronidazole have been reported and recently drug resistance is now on the rise in the world. This study was aimed to determine current susceptibility of Iranian isolates of Trichomonas vaginalis to metronidazole. METHODS: This study was performed on 50 T. vaginalis isolates collected from west and central areas of Iran. After axenisation of the parasites, susceptibility testing was carried out by using serial twofold dilutions of metronidazole (400 to 0.1 µg/ml). The minimum inhibitory concentration (MIC) and the minimum lethal concentration (MLC) of the trichomonads were determined after 48 h incubation at 35.5 °C. Drug susceptibility assays of the all isolates were carried out two times in triplicate under aerobic and anaerobic conditions. RESULTS: Ninety-eight percent of the T. vaginalis isolates (49/50) were sensitive to metronidazole. Metronidazole resistance was defined as aerobic MIC ≥50 µg/ml, detected in one isolate. The means of aerobic MICs and MLCs and that of anaerobic MICs of the parasites were 2.91, 1.95 and 0.28 µg/ml, respectively. CONCLUSION: This investigation showed in vitro low-level tolerance to metronidazole in a few T. vaginalis isolates that may be leading to the development of drug resistance.

Genetic Identification of Trichomonas vaginalis by Using the Actin Gene and Molecular Based Methods.

BACKGROUND: Trichomonas vaginalis is the agent of urogenital tract infection that causes human trichomoniasis with some serious health complications. More understanding about genetic features of the parasite can be helpful in the study of the pathogenesis, drug susceptibility and epidemiology of the infection. For this end, we conducted analysis of the actin gene of T. vaginalis by applying the PCR-SSCP (PCR-Single Stranded Conformational Polymorphism) and nucleotide sequencing method. METHODS: Fifty T. vaginalis samples were collected from 950 women attending gynecology clinics in two cities of Iran, Hamadan and Tehran, from November 2010 to July 2011. After axenisation of isolates, all samples subjected to PCR-SSCP and nucleotide sequencing. RESULTS: According to the SSCP banding patterns and nucleotide sequencing, seven sequence types were detected among the isolates. Alignment of the nucleotide sequences showed five polymorphic sites in the different strain types. Amino acid substitution was not observed in the nucleotide sequence translation of the all sequences. CONCLUSION: The actin gene analysis represents genetic diversity of T. vaginalis and it suggests that various strains can be responsible for clinically different trichomoniasis in infected individuals. It is expected that further studies will be conducted to increase our knowledge about relationship between the actin gene polymorphism and different biological behavior of the parasite.