Challenging TaqMan probe-based real-time PCR and loop-mediated isothermal amplification (LAMP): the two sensitive molecular techniques for the detection of toxoplasmosis, a potentially dangerous opportunistic infection in immunocompromised patients.

Due to defects and drawbacks of most conventional diagnostic methods including serology for the diagnosis of toxoplasmosis as a dangerous opportunistic infection in immunocompromised individuals, the accurate, rapid, and sensitive detection of infection in such patients is essential. In this study, the TaqMan probe-based real-time PCR and, a relatively new nucleic acid amplification method, the loop-mediated isothermal amplification (LAMP) technique was compared based on the repetitive elements (RE) sequence to detect Toxoplasma gondii (T. gondii) DNA in blood samples of immunocompromised individuals. During this study, 119 blood samples from immunocompromised cancer patients with renal failure, undergoing dialysis were studied. After DNA extraction from blood samples using the salt extraction method, the molecular techniques of TaqMan probe-based real-time PCR and LAMP were used to investigate the contamination of the samples with T. gondii, based on the 529 bp (RE) sequence of T. gondii. The analytical sensitivity of LAMP and real-time PCR was evaluated by duplicating the five-step serial dilutions of T. gondii tachyzoites from 0.25 to 5×105 spiked tachyzoites per milliliter of the Toxoplasma seronegative blood sample. The extracted DNA from other parasites and human chromosomal DNA were used to determine the specificity of the molecular methods. The obtained results were analyzed using Kappa statistical test and SPSS22 software. Out of 119 studied samples, 7 (5.8%) and 5 (4.2%) samples were positive for Toxoplasma by TaqMan probe-based real-time PCR and LAMP, respectively. The limits of detection of TaqMan probe-based real-time PCR and RE-LAMP in negative serum samples were one and five tachyzoites (CT 38), respectively. Both real-time PCR and LAMP methods were 100% specific for Toxoplasma detection. Positive results were obtained only with T. gondii DNA, while other DNA samples were negative. The TaqMan probe-based real-time PCR based on the RE sequence showed higher sensitivity to T. gondii DNA detection in blood samples of cancer patients and serial dilutions of parasitic tachyzoites. The results show that TaqMan probe-based real-time PRC is a sensitive and specific method for the detection of toxoplasmosis in immunocompromised individuals, as well as the LAMP assay, which can be used as a suitable alternative diagnostic method for the detection of toxoplasmosis in such patients, without need the for any expensive equipment.

Association of levels of interleukin 17 and T-helper 17 count with symptom severity and etiology of chronic heart failure: a case-control study.

AIM: To assess the association between the levels of interleukin 17 (IL-17) and T-helper 17 count and symptom severity and etiology of chronic heart failure. METHODS: This single-center prospective case-control study, conducted from December 1, 2015 to January 1, 2017 in Tehran Heart Center, evaluated gene expression of IL-17, relative count of (CD4+IL17+) Th17 cells and CD4+ helper T-cells in peripheral blood mononuclear cells of 42 patients with CHF and 42 matched controls. A multiple regression model assessed the predictors of peripheral IL-17 expression and Th17 count in patients with CHF. RESULTS: IL-17 expression was increased in patients with CHF, both at baseline and after stimulation. IL-17 and Th17 counts were higher in patients with advanced New York Heart Association (NYHA) functional class (class IV) than in controls and patients with class I. Th17 cell population expanded in patients with CHF, more prominently in patients with class IV than in controls and patients with class I, regardless of the ischemic or non-ischemic CHF origin. Multiple regression model showed that NYHA was the only meaningful predictor of IL-17 levels and Th17 count. CONCLUSION: We demonstrated the lymphocytic origin of IL-17 production in advanced CHF and the ability of disease severity to predict IL-17 levels. Oxford Centre for Evidence-based Medicine level of evidence: 3.

In silico design and construction of metal-binding hybrid proteins for specific removal of cadmium based on CS3 pili display on the surface of Escherichia coli.

In this study, through a combination of bioinformatics and genetic engineering procedures, high-affinity metal-binding peptides were designed and expressed on the surface of Escherichia coli for selective Cd(2+) adsorption. Putative cadmium-binding motifs were identified by searches against the Prosite database and permissive sites in the major subunit (CstH) of the enterotoxigenic E. coli pili were predicted based on the data derived from modeling of 3D structures, secondary structure prediction and assignment, inspection of protein hydropathy and exposed regions, and also protein interaction sites. The metal-binding motifs were inserted into one permissive site of the CstH (amino acid 38) with the aid of the SOEing PCR technique. The capacity and selectivity of the recombinant bacteria displaying hybrid pili to adsorb cadmium were evaluated with the atomic absorption procedure. The levels of Cd(2+) accumulation in the recombinant E. coli strains were 13.9- and 11.33-fold higher than those in the control strain. Cd(2+) was selectively absorbed from a solution containing equal concentrations of four metals, resulting in more than 90% of the total adsorbed metals being Cd(2+) , showing a relatively high affinity for Cd(2+) over other coexisting metal ions.

Repurposing the natural compounds as potential therapeutic agents for COVID-19 based on the molecular docking study of the main protease and the receptor-binding domain of spike protein.

Severe acute respiratory syndrome coronavirus (SARS-CoV-2) enters the cell by interacting with the human angiotensin-converting enzyme 2 (ACE2) receptor through the receptor-binding domain (RBD) of spike (S) protein. In the cell, the viral 3-chymotrypsin-like cysteine protease (3CLpro) enzyme is essential for its life cycle and controls coronavirus replication. Therefore, the S-RBD and 3CLpro are hot targets for drug discovery against SARS-CoV-2. This study was to identify repurposing drugs using in silico screening, docking, and molecular dynamics simulation. The study identified bentiamine, folic acid, benfotiamine, and vitamin B12 against the RBD of S protein and bentiamine, folic acid, fursultiamine, and riboflavin to 3CLpro. The strong and stable binding of these safe and cheap vitamins at the important residues (R403, K417, Y449, Y453, N501, and Y505) in the S-protein-ACE2 interface and 3CLpro binding site residues especially active site residues (His 41 and Cys 145), indicating that they could be valuable repurpose drugs for inhibiting SARS-CoV-2 entry into the host and replication.

Gene Expression and Levels of TGF-B in PBMC Is Associated with Severity of Symptoms in Chronic Heart Failure.

BACKGROUND: TGF-ß1 is known to promote cardiac remodeling and fibrosis during Congestive Heart Failure (CHF). In this study, an attempt was made to investigate expression of Transforming Growth Factor beta1 (TGF-ß1) and relative expansion or contraction of regulatory T-cell (Tregs) population in peripheral blood of patients with Chronic Heart Failure (CHF). METHODS: Real-time PCR assay was used to investigate expression and post-stimulation levels of TGF-ß1 in cell culture supernatant of Peripheral Blood Mononuclear Cells (PBMC) of 42 patients with CHF and 42 controls. Flow cytometry was used to identify relative counts of CD4+CD25+FoxP3+ Tregs. RESULTS: PBMCs in patients with CHF expressed higher levels of TGF-ß1 compared to controls. Post-stimulation levels of TGF-ß1 expression were significantly higher in New York Heart Association (NYHA) functional class IV patients compared to stage I patients. Tregs were significantly expanded in PBMC in CHF, while the CD4+ helper T-cells were unchanged. Treg expansion was more significant in NYHA functional class I patients compared to class IV patients. CONCLUSION: Expansion of Treg population in CHF provides an extrinsic source for TGF-ß1 production to induce reactive fibrosis and cardiac remodeling. Relative decrease in Treg population at advanced stages of CHF is indicative of a loss of regulatory characteristics in these cells and unopposed proinflammatory milieu.

Efficient Cadmium Bioaccumulation by Displayed Hybrid CS3 Pili: Effect of Heavy Metal Binding Motif Insertion Site on Adsorption Capacity and Selectivity.

The objective of this study was to evaluate the influence of insertion site of the metal binding motif on the bioaccumulation capacity of the hybrid CS3 pili displayed on the surface of Escherichia coli using both computational and experimental methods. Two metal binding motifs (cadmium binding motif (cbm) and cadmium binding beta motif (cbßm)), identified by searching against the PROSITE database, were inserted into five putative permissive sites of CstH protein (CS3 pili subunit) by using SOEing PCR technique. The expression and surface display of the hybrid pili were evaluated using dot and Western blotting methods and also immunofluorescence microscopy. The cadmium binding affinity and selectivity of the recombinant bacteria displaying various hybrid pili were evaluated using atomic absorption procedure. The results showed that the cadmium binding motifs enabled the cells to sequester cadmium 8- to 16-fold higher than the E.coli expressing native pili. The location of the metal binding motifs in the pili subunit had also a significant effect on the metal-binding properties of the hybrid pili. The insertion at positions 107-108 and 92-93 of the mature CstH showed the highest adsorption in comparison to other positions.