Nanovaccine: A novel approach in immunization

Despite great advances in the field of vaccination, there are still needs for novel and effective vaccines because still no effective vaccines have been produced for some diseases such as malaria, acquired immune deficiency syndrome (AIDS), and tuberculosis. Furthermore, many of the existing vaccines have disadvantages such as failure to stimulate completely the immune system, in vivo instability, high toxicity, the need for cold chain, and multiple administrations. Nanotechnology has been raised as a powerful tool for solving these problems in this regard. Generally, nanovaccines are a new generation of vaccines using nanoparticles (NPs) as carriers and/or adjuvants. Due to the similar scale (size) between the NPs and pathogens, the immune system can be stimulated well, resulting in triggered cellular and humoral immunity responses. Other benefits of the nanovaccines include their better stability in blood flow to increase the shelf life in blood, enhanced immune system stimulation, no need for booster doses, no need to maintain the cold chain, and ability to create active targeting. In addition, nanovaccines have raised the hope to treat diseases such as rheumatoid arthritis, AIDS, malaria, and chronic autoimmune, and so forth.     

Study of interactions between DNA and aflatoxin B1 using electrochemical and fluorescence methods

In this study, a carbon paste electrode modified with N-butylpyridinium hexafluorophosphate (BPPF₆) ionic liquid and DNA was introduced as an electrochemical biosensor to study the interaction between DNA and aflatoxin B1 molecules. For this purpose, variations in oxidation peak current of guanine in various concentrations of aflatoxin B1 were measured by using the differential pulse voltammetry (DPV) method. According to this study, the binding constant of DNA–aflatoxin B1 was found to be 3.5 × 10⁶ M⁻¹. This modified electrode was also used for determination of low concentrations of aflatoxin B1 by using differential pulse voltammetry. A linear dynamic range from 8.00 × 10⁻⁸ to 5.91 × 10⁻⁷ M and a limit of detection of 2.00 × 10⁻⁸ M resulted from DPV measurements. To confirm our results, a fluorescence study was also performed. It resulted in a binding constant of 2.8 × 10⁶ M⁻¹, which is in good agreement with that obtained from electrochemical study.     

Differentiation and Classification of Phytoplasmas Associated with Almond and GF‐677 Witches'‐Broom Diseases using rRNA and rp Genes

Stone fruits are affected by several diseases associated with plant pathogenic phytoplasmas. Previous studies have been shown that phytoplasma agents of almond and GF‐677 witches'‐broom (AlmWB and GWB, respectively) diseases belong to pigeon pea witches'‐broom (16SrIX) phytoplasma group. In this study, partial biological and molecular characterization was used to compare and classify phytoplasma agents of Khafr AlmWB (KAlmWB) and Estahban GWB (EGWB) diseases. Production of different symptoms in periwinkle indicated that agents of KAlmWB and EGWB are differentiable. Expected fragments were amplified from diseased almond and GF‐677 trees in direct PCR using phytoplasma universal primer pairs P1/P7 and rpF1/rpR1 and nested PCR using P1/P7 followed by R16F2n/ R16R2 primer pair. 16S‐rDNA Restriction fragment length polymorphism (RFLP) as well as phylogenetic analysis of rplV‐rpsC and 16S–23S rRNA spacer region sequences classified KAlmWB and EGWB phytoplasmas within 16SrIX‐C (rpIX‐C) and 16SrIX‐B (rpIX‐B) subgroups, respectively.     

Role of disulfide bonds in modulating internal motions of proteins to tune their function: molecular dynamics simulation of scorpion toxin Lqh III

A series of 1-ns MD simulations were performed on the scorpion toxin Lqh III in native and disulfide bond broken states. The removal of disulfide bonds has caused hydrogen bond network alteration in the five-residue turn, the long loop, the alpha-helix, the loop connecting strands II and III, and the C-terminal region. In addition and more importantly, it has influenced the amplitude of the fluctuations of five-residue turn, loops, and C-terminal region with a minor effect on the fluctuations of the cysteines in the broken bond sites. These findings suggest that disulfide bonds are not the most important factors in rigidifying their own locations, while they have more important effects at a global scale. Furthermore, our results reveal that disulfide bonds have considerable influence on the functionally important essential modes of motions and the correlations between the motions of the binding site residues. Therefore, we can conclude that disulfide bonds have a crucial role in modulating the function via adjusting the dynamics of scorpion toxin molecules. Although this conclusion cannot be generalized to all peptides and proteins, it demonstrates the importance of more investigations on this aspect of disulfide bond efficacy.     

Lung vasodilatory response to inhaled iloprost in experimental pulmonary hypertension: amplification by different type phosphodiesterase inhibitors

Inhaled prostanoids and phosphodiesterase (PDE) inhibitors have been suggested for treatment of severe pulmonary hypertension. In catheterized rabbits with acute pulmonary hypertension induced by continuous infusion of the stable thromboxane analogue U46619, we asked whether sildenafil (PDE1/5/6 inhibitor), motapizone (PDE3 inhibitor) or 8-Methoxymethyl-IBMX (PDE1 inhibitor) synergize with inhaled iloprost. Inhalation of iloprost caused a transient pulmonary artery pressure decline, levelling off within <20 min, without significant changes in blood gases or systemic hemodynamics. Infusion of 8-Methoxymethyl-IBMX, motapizone and sildenafil caused each a dose-dependent decrease in pulmonary artery pressure, with sildenafil possessing the highest efficacy and at the same time selectivity for the pulmonary circulation. When combining a per se ineffective dose of each PDE inhibitor (200 μg/kg × min 8-Methoxymethyl-IBMX, 1 μg/kg × min sildenafil, 5 μg/kg × min motapizone) with subsequent iloprost nebulization, marked amplification of the prostanoid induced pulmonary vasodilatory response was noted and the area under the curve of P_PA reduction was nearly threefold increased with all approaches, as compared to sole iloprost administration. Further amplification was achieved with the combination of inhaled iloprost with sildenafil plus motapizone, but not with sildenafil plus 8MM-IBMX. Systemic hemodynamics and gas exchange were not altered for all combinations. We conclude that co-administration of minute systemic doses of selective PDE inhibitors with inhaled iloprost markedly enhances and prolongs the pulmonary vasodilatory response to inhaled iloprost, with maintenance of pulmonary selectivity and ventilation perfusion matching. The prominent effect of sildenafil may be operative via both PDE1 and PDE5, and is further enhanced by co-application of a PDE3 inhibitor.     

The codon-optimization of cfaE gene and evaluating its high expression capacity and conserved immunogenicity in Escherichia coli

Enterotoxigenic Escherichia coli (ETEC) is the most common cause of children diarrhea in the world. Adhesion of ETEC to small intestine is an important virulence trait. One of the most prevalent colonization factors (CFs) in human is CFA/I fimbriae and CfaE which is the required binding factor for adhesion of ETEC to intestinal mucosa.We optimized cfaE gene codons according to codon bias of E. coli to achieve a high level of recombinant protein expression. The optimized gene was expressed in E. coli and rCFaE protein was used for mice immunization. Blocking activity of the obtained antibody was examined by microplate agglutination inhibition test. SDS-PAGE analysis indicated that the optimized sequence of cfaE produces a suitable amount of rCFaE in comparison with native gene sequence. This optimized rCFaE protein could induces strong humoral response in mice and the antibody obtained against rCFaE inhibited the adhesion of ETEC to human group A erythrocytes. It is concluded that codon optimization is a useful approach for obtaining large quantities of recombinant rCFaE protein. With regard to the results of hemagglutination inhibition test, codon optimization and increased production of recombinant protein expressed in E. coli did not affect the immunogenicity potential of CFaE.     

The molecular behavior of a single β‐amyloid inside a dipalmitoylphosphatidylcholine bilayer at three different temperatures: An atomistic simulation study: Aβ interaction with DPPC: Atomistic simulation

The behavior of a single Aβ40 molecule within a dipalmitoylphosphatidylcholine (DPPC) bilayer was studied by all‐atom molecular dynamics simulations. The effect of membrane structure was investigated on Aβ40 behavior, secondary structure, and insertion depth. Simulations were performed at three temperatures (323, 310, and 300 K) to probe three different bilayer fluidities. Results show that at all above temperatures, the peptide contains two short helices, coil, bend, and turn structures. At 300 K, the peptide contains a region with β structure in C‐terminal region. Our results also show that Aβ decreases the bilayer thickness and the order of lipids in its vicinity which leads to water insertion into the bilayer and concomitant increase in the local fluidity. The peptide remains embedded in the bilayer at all temperatures, and become inserted into the bilayer up to several residues at 323 and 310 K. At 310 and 300 K, the dominant interaction energy between Aβ and bilayer changes from electrostatic to van der Waals. It can be proposed that at higher temperatures (e.g., 323 K), Lys28 and the C‐terminal region of the peptide play the role of two anchors that keep Aβ inside the top leaflet. This study demonstrates that Aβ molecule can perturb the integrity of cellular membranes. Proteins 2017; 85:1298–1310. © 2017 Wiley Periodicals, Inc.     

Delivery of HIV-1 Nef Protein in Mammalian Cells Using Cell Penetrating Peptides as a Candidate Therapeutic Vaccine

The HIV-1 Nef protein expressed early in viral life cycle has been known as a potent candidate for therapeutic vaccine development. Due to different cell barriers, various cell penetrating peptides (CPPs) such as Pep-1 and CADY-2 have been known to deliver biologically active proteins to cytoplasmic compartments via the plasma membrane. In current study, we firstly evaluated the efficiency of lentiviral vector (pCDH-CMV-MCS-EF1-cGFP-T2A-puro) and eukaryotic expression vector (pEGFP-N1) for expression of HIV-1 Nef protein in HEK-293T cells using TurboFect transfection reagent. Our results showed that both vectors can effectively express the Nef proteins within the target cell. The pEGFP-N1 was more effective than pCDH-GFP for protein expression. Furthermore, Nef protein was expressed in E. coli as GST-Nef fusion and transfected by the amphipathic CPPs including Pep-1 and CADY-2 into HEK-293T cells. The size and morphology of the GST-Nef/CPP complexes were evaluated by scanning electron microscopy, and Zetasizer. Our data indicated that the recombinant GST-Nef protein generated in BL21 strain migrated as a clear band of ~50 kDa in SDS-PAGE. The CPP/GST-Nef nanoparticles were formed with a diameter of below 200 nm and notably delivered into HEK-293T cells. Generally, the Nef protein was expressed in prokaryotic and eukaryotic expression systems using different vectors and efficiently transfected in mammalian cells using various delivery systems. The in vitro efficient delivery of HIV-1 Nef gene and also its protein supports the potential of Nef DNA constructs and CPPs as potent carriers of Nef protein for HIV vaccine design in Future.     

Bioaccumulation of Trace Mercury in Trophic Levels of Benthic, Benthopelagic, Pelagic Fish Species, and Sea Birds from Arvand River, Iran

In this study, concentration of mercury was determined in the trophic levels of benthic, benthopelagic, pelagic fish species, and river birds from Arvand River, located in the Khuzestan province in the lowlands of southwestern Iran at the head of the Persian Gulf. The order of mercury concentrations in tissues of the fish species was as follows: liver>gill>muscle and in tissues of the kingfisher species was as follows: feather>liver>kidney>muscle. Therefore, liver in fish and feather in kingfisher exhibited higher mercury concentration than the other tissues. There was a positive correlation between mercury concentrations in fish and kingfisher species with size of its food items. We expected to see higher mercury levels in tissues of female species because they are larger and can eat larger food items. The results of this study show that the highest mean mercury level were found in the kingfisher (Anas crecca), followed by benthic (Epinephelus diacanthus), benthopelagic (Chanos chanos), and pelagic fish (Strongylura strongylura). Mean value of mercury in fish species, S. strongylura were (0.61 μg g^?1 dry weight), C. chanos (0.45 μg g^?1 dry weight), E. diacanthus (0.87 μg g^?1 dry weight), and in kingfisher species A. crecca was (2.64 μg g^?1 dry weight). Significant correlation between mercury concentration in fish and kingfisher may be related to high variability of mercury in the fish.     

Cold atmospheric plasma induced genotoxicity and cytotoxicity in esophageal cancer cells

Molecular Biology Reports - In this paper, we studied the functional effects of cold atmospheric plasma (CAP) on the esophageal cancer cell line (KYSE-30) by direct and indirect treatment and...