The XylR regulatory protein is a transcriptional activator from the TOL plasmid of Pseudomonas putida mt-2 that is involved in the toluene and benzene degradation pathway. Here we describe the construction and laboratory characterization of recombinant biosensors (pGLPX plasmids) based on XylR and its cognate promoter (Pu). In the pGLPX plasmid, the reporter luc gene is under the control of the Pu promoter. We evaluated the ability of two distinct nucleotide sequences to function as SD elements and improve sensitivity of bioreporting. We also evaluated the effect of introducing the T₂rrnβ terminator on the specificity of the construct. E. coli transformed with pGLPX plasmids were used to sense toluene and its derivatives. The pattern of induction was different for each derivative. In general, more luciferase activity was induced by toluene and benzene than by TNT and DNT at most tested concentrations. The bioluminescence response of the reporter strains to the nitrotoluenes was significantly stronger at lower concentrations (≥ 50 μmol) than at higher concentrations. Our results show that the SD sequence (taaggagg) is crucially important for biosensor sensitivity. The presence of the T₂rrnβ terminator in the bioreporter plasmid prevents nonspecific responses and also reduces biosensor sensitivity upon exposure to inducers. These data suggest that pGLPX strains can be used as whole-cell biosensors to detect toluene and related compounds. Further investigation will be required to optimize the application of pGLPX biosensors.

Background: Despite the high yearly prevalence of Influenza, the pathogenesis mechanism and involved genes have not been fully known. Finding the patterns and mapping the complex interactions between different genes help us to find the possible biomarkers and treatment targets. Methods: Herein, weighted gene co-expression network analysis (WGCNA) was employed to construct a co-expression network among genes identified by microarray analysis of the pediatric influenza-infected samples. Results: Three of the 38 modules were found as the most related modules to influenza infection. At a functional level, we found that the genes in these modules regulate the immune responses, protein targeting, and defense to virus. Moreover, the analysis of differentially expressed genes disclosed 719 DEGs between the normal and infected subjects. The comprehensive investigation of genes in the module involved in immune system and viral defense (yellow module) revealed that SP110, HERC5, SAMD9L, RTP4, C19orf66, HELZ2, EPSTI1, and PHF11 which were also identified as DEGs (except C19orf66) have the potential to be as the biomarkers and also drug targeting for the treatment of pediatric influenza. Conclusions: The WGCN analysis revealed co-expressed genes which were involved in the innate immune system and defense to virus. The differentially expressed genes in the identified modules can be considered for designing drug targets. Moreover, modules can help to find pathogenesis routes in the future.

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Influenza A viruses are an important cause of severe infectious diseases in humans and are characterized by their fast evolution rate. Global monitoring of these viruses is critical to detect newly emerging variants during annual epidemics. Here, we sought to genetically characterize influenza A/H1N1pdm09 and A/H3N2 viruses collected in Iran during the 2014-2015 influenza season. A total of 200 nasopharyngeal swabs were collected from patients with influenza-like illnesses. Swabs were screened for influenza A and B using real-time PCR. Furthermore, positive specimens with high virus load underwent virus isolation and genetic characterization of their hemagglutinin (HA) and M genes. Of the 200 specimens, 80 were influenza A-positive, including 44 A/H1N1pdm09 and 36 A/H3N2, while 18 were influenza B-positive. Phylogenetic analysis of the HA genes of the A/H1N1pdm09 viruses revealed the circulation of clade 6C, characterized by amino acid substitutions D97N, V234I and K283E. Analysis of the A/H3N2 viruses showed a genetic drift from the vaccine strain A/Texas/50/2012 with 5 mutations (T128A, R142G, N145S, P198S and S219F) belonging to the antigenic sites A, B, and D of the HA protein. The A/H3N2 viruses belonged to phylogenetic clades 3C.2 and 3C.3. The M gene trees of the Iranian A/H1N1pdm09 and A/H3N2 mirrored the clustering patterns of their corresponding HA trees. Our results reveal co-circulation of several influenza A virus strains in Iran during the 2014-2015 influenza season.

Hepatitis D (delta) virus (HDV) is a subviral pathogen agent and a satellite of Hepatitis B virus. Three distinct genotypes are described for HDV; genotype I is distributed worldwide but other genotypes appear to be more restricted geographically. In the present study, the entire nucleotide sequence of an HDV isolate from an Iranian patient (IR-1) was obtained using twelve pairs of primers to amplify six overlapping fragments covering the whole HDV genome by RT-nested PCR. Phylogenetic and pairwise alignments were done on this new isolate to determine IR-1 position among other isolates. Our results indicate that IR-1 contains 1676 nucleotides encoding 214 a.a. of the hepatitis delta antigen (HDAg). This new isolate belongs to genotype I with most sequence similarity to an Italian HDV isolate (92.6%). At amino acid level, predicted HDAg sequence of IR-1 revealed the most homology with those of Italian and Lebanese isolates. Data analysis confirmed genetic variability and heterogeneity of the HDV species isolated from different geographical areas.

The ongoing evolution of influenza viruses and the detect of influenza viruses with reduced susceptibility to NAIs warrants continuous monitoring of the circulating strains.

An aequorin-based Escherichia coli strain JM109 biosensor was constructed and characterized for its potential to detect toluene and related compounds in aqueous solutions. The biosensor was constructed based on a PGL2 plasmid carrying the lower pathway promoter (Pu) of the xyl operon of Pseudomonas putida mt-2, which was incorporated with transcriptional activator xylR and fused to aequorin cDNA named pGL2-aequorin. Binding of xylR protein to a subset of toluene-like compounds activates transcription at the Pu promoter, thus expression of aequorin is controlled by xylR and Pu. In this work we have compared the effect of Shine-Dalgarno (SD) and T2 rrnβ terminator sequence in the expression of aequorin. According to the sensitivity of aequorin and increase in the signal-to-noise ratio, this reporter enzyme has reasonable sensitivity compared with other reporter systems. The results indicate higher expression of aequorin in the presence of SD and T2 rrnβ. The activity of aequorin in recombinant whole-cell biosensor was linear from 1 to 500 μm of toluene. The bioluminescence response was specific for toluene-like molecules, so this biosensor cells would be able to detect toluene derivative contamination in environmental samples, accurately.

<b><i>Introduction:</i></b> Chronic fatigue syndrome (CFS) is a neurological disease that is accompanied by excessive fatigue or tiredness. There are several reports confirming the association between human herpesvirus 6 (HHV-6) infection and CFS illness. This systematic review and meta-analysis was performed to integrate the information of published studies with regard to this association until May 2021. <b><i>Methods:</i></b> The literature search was based on keywords including “chronic fatigue syndrome and HHV 6,” “chronic fatigue syndrome and HHV-6,” “chronic fatigue syndrome and HHV6,” “chronic fatigue syndrome and Herpes virus 6,” and “chronic fatigue syndrome and Herpesvirus6” in MEDLINE (PubMed), Web of Science, and EMBASE. <b><i>Results:</i></b> The literature search identified 17 studies to be included in the systematic review and 11 studies in meta-analysis. The symmetry funnel plot and Egger’s test (<i>p</i> value = 0.2) identified no publication bias among studies. Moreover, the low level of <i>I</i>² revealed homogeneity across studies. <b><i>Discussion:</i></b> In conclusion, the association between the HHV-6 infection and CFS incidence was substantiated. However, the results of this study also suggest that further comprehensive studies are needed to solidify the association between HHV-6 and CFS. Future studies should consider additional factors that may have affected the significance of such a correlation.