Antibacterial activity of Lake Urmia derived-Halomonas

Isolation of new microbial species from extreme environments is one of the most efficient approaches for the development of novel bioactive metabolites. The aim of the present study was to explore the pharmaceutical bacterial resources from the water and sediments of hypersaline Lake Urmia. Using different culture conditions and media led to the isolation of 20 bacterial strains. Halophilic bacteria were screened for the production of antibacterial agent against multi-drug resistant strains of Escherichia coli through agar well diffusion assay. Halophilic bacteria DNA extraction was done by boiling method. The results showed that two Halomonas strains, LUH16 and LUH20 identified by analysis of 16S rRNA gene sequences were the potent producers of antimicrobial metabolites against various strains of E. coli. Furthermore, gas chromatography-mass spectrometry (GC-MS) analysis revealed the presence of eight secondary metabolites with the relevant antimicrobial properties. Our findings led us to focus on Halomonas strains as potent producers of antimicrobial compound that might be an alternative against antibiotic-resistant pathogens such as pathogenic Escherichia coli.

An Ultrasensitive miRNA-Based Genosensor for Detection of MicroRNA 21 in Gastric Cancer Cells Based on Functional Signal Amplifier and Synthesized Perovskite-Graphene Oxide and AuNPs

In the present research work, the state-of-art label-free electrochemical genosensing platform was developed based on the hybridization process in the presence of [Fe(CN)₆]^3-/4- as an efficient redox probe for sensitive recognition of the miRNA-21 in human gastric cell lines samples. To attain this aim, perovskite nanosheets were initially synthesized. Afterward, the obtained compound was combined with the graphene oxide resulting in an effective electrochemical modifier, which was dropped on the surface of the Au electrode. Then, AuNPs (Gold Nano Particles) have been electrochemically-immobilized on perovskite-graphene oxide/Au-modified electrode surface through the chronoamperometry (CA) technique. Finally, a self-assembling monolayer reaction of ss-capture RNA ensued by the thiol group at the end of the probe with AuNPs on the modified electrode surface. miRNA-21 has been cast on the Au electrode surface to apply the hybridization process. To find out the effectiveness of the synthesized modifier agent, the electrochemical behavior of the modified electrode has been analyzed through DPV (differential pulse voltammetry) and CV (cyclic voltammetry) techniques. The prepared biomarker-detection bioassay offers high sensitivity and specificity, good performance, and appropriate precision and accuracy for the highly-sensitive determination of miRNA-21. Different characterization methods have been used, such as XRD, Raman, EDS, and FE-SEM, for morphological characterization and investigation of particle size. Based on optimal conditions, the limit of detection and quantification have been acquired at 2.94 fM and 8.75 fM, respectively. Furthermore, it was possible to achieve a wide linear range which is between 10^-14 and 10^-7 for miRNA-21. Moreover, the selectivity of the proposed biosensing assay was investigated through its potential in the detection of one, two, and three-base mismatched sequences. Moreover, it was possible to investigate the repeatability and reproducibility of the related bio-assay. To evaluate the hybridization process, it is important that the planned biomarker detection bio-assay could be directly re-used and re-generated.

Isolation of a lytic bacteriophage against extensively drug-resistant Acinetobacter baumannii infections and its dramatic effect in rat model of burn infection

Objectives

Acinetobacter Baumannii is an opportunistic nosocomial pathogen belonging to the Moraxellaceae family. The emergence of multidrug resistant strains of this pathogen caused many problems for hospitals and patients. The aim of the current study was to isolate, identify, and morphologically, physiologically, and in vivo analyze a new lytic bacteriophage targeting extensively drug‐resistant (XDR) A. baumannii.

Materials and Methods

Different wastewater samples were tested for isolation of lytic bacteriophage against 19 A. baumannii isolates obtained from patients hospitalized in a hospital in Arak, Iran, from January 2019 to March 2019. The phenotypic and genotypic characteristics of A. baumannii strains (resistance genes including: adeA, adeB, adeC, adeR, adeS, ISAba1, blaOXA‐23, blaOXA‐24) were analyzed. The isolated phage characteristics including adsorption time, pH and thermal stability, host range, one‐step growth rate, electron microscopy examination, and therapeutic efficacy of the phage were also investigated. Therapeutic efficacy of the phage was evaluated in a rat model with burn infection of XDR A. baumannii. The lesion image was taken on different days after burning and infection induction and was compared with phage untreated lesions.

Results

The results showed unique characteristics of the isolated phage (vB‐AbauM‐Arak1) including high specificity for Acinetobacter baumannii, stability at a relatively wide range of temperatures and pH values, short adsorption time, short latent period, and large burst size. In relation to the therapeutic efficacy of the phage, the lesion area decreased in phage‐treated groups over 14 days than in those untreated, significantly (p < 0.05).

Conclusion

Our findings demonstrated that isolated lytic phage was able to eliminate burn infections caused by XDR A. baumannii in a rat model. So, it may be recommended as alternative options toward to developing a treatment for extensively drug resistant Acinetobacter infections.

Cytotoxic effect of sea anemone pore-forming toxin on K562 chronic myeloid leukemia cells

Chronic myelogenous leukemia (CML) is one of prevalent cancer worldwide. In spite of various designed drugs, chemoresistance remains the main obstacle in cancer cure. Therefore, developing novel strategy for treatment of CML is an urgent need. Fragaceatoxin C (FraC) is novel protein toxin from a sea anemone called actinia fragacea with great impacts against cells by pore formation and disturbing cell membrane integrity. The aim of this study was evaluation of FraC toxin toxicity against K562. The bacteria cells harboring expression‌‌‌‌‌‌‌ vector of FraC were induced by IPTG and purified by Ni²⁺-NTA sepharose affinity chromatography. Then, purified toxin activity was evaluated using RBC hemolytic test. Eventually, evaluation of FraC cytotoxicity and apoptosis were performed using MTT and flow cytometery assays, respectively. Our results revealed that FraC toxin decreased K562 cells viability in a dose- and time-dependent manner with a whole destroy of cancer cells at 35.00 µg mL^-1 after 72 hr. Furthermore, flow cytometery analysis indicated that FraC toxin enhanced necrosis along with apoptosis in K562 cells in a dose dependent manner. We speculated that FraC toxin could be considered as a novel candidate for cancer cell researches and treatments provided that it should be turned into a specific agent by engineering and directing to cancer cell membrane.

Association of Herpes simplex virus I&II infections with rs187084 SNP of TLR9 and male infertility

Since TLR9 recognises unmethylated CpG motifs in viral DNA, its polymorphisms may contribute to the susceptibility to Herpes simplex virus I&II infection. In the present study, to evaluate the role of rs187084 SNP (single nucleotide polymorphism) of TLR9 in Herpes simplex virus I&II infection and male infertility, 103 infertile and 27 fertile blood and semen samples were analysed. We assessed the micro and macro properties of semen specimens and the presence of HSV immunoglobulins. Tetra-primer ARMS PCR was used to detect SNP and to investigate the genotype distribution of TLR9-rs187084 SNPs, and the correlation between polymorphisms of TLR9 gene and male infertility. Moreover, the odds ratio (OR) and 95% confidence intervals were used to estimate the strength of the association. Based on our finding, a significant correlation was observed between HSV infection, agglutination and polymorphism (TT) under dominant (OR = 1.28, 95% CI = 0.94-1.75) and recessive (OR = 0.44, 95% CI = 0.21-0.94) models for the data, which was complied with Hardy-Weinberg equilibrium (HWE) (OR = 2.91, 95% CI = 1.02-8.30). The result showed a significant association between HSV IgM and agglutination in HSV infection (p < .001), and in addition, there were associations between alleles so that rs187084 SNP might be considered as a risk factor for the incidence of HSV infection.

Comparing the Bacteriostatic Effects of Different Metal Nanoparticles Against Proteus vulgaris

For many years, researchers were looking for new antibacterial substances to deal with hospital infections and especially resistant infections. Nanoparticles attracted much attentions because of their very small size that increases the surface to capacity ratio and consequently increase chemical activity. In this study, the antibacterial effects of silver, copper oxide, nickel oxide, and titanium dioxide nanoparticles were studied on Proteus vulgaris, as a bacterium involved in the resistant hospital infections. The capability of nanoparticles to inhibit the growth of bacteria was assessed via 9 different methods including cylinder, disk, and well-diffusion, spot test, MBC, MIC, liquid inhibitory action test, diffusion, and assessing the effects of nanoparticles on a 24-h culture. Based on the results, copper oxide and silver nanoparticles had high antibacterial effects on P. vulgaris in both liquid and solid cultures, respectively. However, nickel oxide and titanium dioxide nanoparticles only had a weak effect on the inhibition of bacterial growth in the liquid culture. CuO and Ag NPs could release ions and consequently produce free radicals, disturb the equilibrium of electrons between electron donor groups and inactivate enzymes and DNA of the organisms. Moreover, they triggered holes in the bacterial membrane to disturb cellular ion equilibrium. So, they can be used to inhibit the growth of pathogens. Besides, further studies have shown that they could be used as a supplementary treatment and/or in combination with other drugs to cure infections caused by P. vulgaris.

Torque teno mini virus infection and multiple sclerosis

Multiple sclerosis (MS) is a disease of young adults which is characterized by autoimmune demyelination of the central nervous system. Interaction of genetics and environmental factors are required to cause MS. Among the proposed environmental factors for MS, viral infections are thought to play a role in the pathogenesis of the disease. Torque teno mini virus (TTMV), which has recently been shown to infect humans, is a member of circoviridae, and has a circular DNA with 2860 nucleotides. Since there are a few data about the pathogenicity of this virus, this study sought to investigate the presence of TTMV in sera from MS patients and healthy individuals. We studied 149 serum samples from MS patients and 150 sera of healthy individuals. Serum DNA was extracted using phenol-chloroform and was subjected to nested polymerase chain reaction. TTMV-DNA was detected in 24 (16%) sera of the healthy blood donors and in 21 (14.1%) samples of the MS patients, where the difference did not reach significance (p > .05). The result of this study could not establish an association between TTMV infection and MS.