Horizontal Gene Transfer and the Diversity of <i>Escherichia coli</i>

Escherichia coli (E. coli) strains are normal flora of human gastrointestinal tract. The evolution encoded by horizontally-transferred genetic (HGT) elements has been perceived in several species. E. coli strains have acquired virulence potential factors by attainment of particular loci through HGT, transposons or phages. The heterogeneous nature of these strains is because of HGT through mobile genetic elements. These genetic exchanges that occur in bacteria provide the genetic diversity

Designing novel construction for cell surface display of protein E on Escherichia coli using non-classical pathway based on Lpp-OmpA

Additional file 2. pNon-OmpA-PE. ab1. Sequencing result of pNon-OmpA-PE

Improvement Of Hgm-Csf Expression Using A Fusion System By Directing Protein To The Periplasmic Space

Bacterial expression systems provide economic and logistic advantages in manufacturing proteins for human therapeutic purposes. However, most such proteins accumulate in insoluble biologically inactive form when overexpressed in bacterial cells. This is the case while attempting to produce recombinant human granulocyte-macrophage colony stimulating factor (hGM-CSF) in E. coli. In this report, different strong promoters are used to compare the yield of expression when the protein is expressed as insoluble and soluble forms. The results obtained indicated that the level of expression was independent of the nature of promoter used. Moreover experimental data presented here suggest that the fusion system which directs hGM-CSF to the periplasmic space not only can prevent inclusion body formation but also improve the level of expression significantly

Signature Prediction Modeling in Cytolethal Distending Toxin-Producing Strains

In this study, cytolethal distending toxin (CDT) producer isolates genome were compared with genome of pathogenic and commensal Escherichia coli strains. Conserved genomic signatures among different types of CDT producer E. coli strains were assessed. It was shown that they could be used as biomarkers for research purposes and clinical diagnosis by polymerase chain reaction, or in vaccine development. cdt genes and several other genetic biomarkers were identified as signature sequences in CDT producer strains. The identified signatures include several individual phage proteins (holins, nucleases, and terminases, and transferases) and multiple members of different protein families (the lambda family, phage-integrase family, phage-tail tape protein family, putative membrane proteins, regulatory proteins, restriction-modification system proteins, tail fiber-assembly proteins, base plate-assembly proteins, and other prophage tail-related proteins). In this study, a sporadic phylogenic pattern was demonstrated in the CDT-producing strains. In conclusion, conserved signature proteins in a wide range of pathogenic bacterial strains can potentially be used in modern vaccine-design strategies

Modulation of Molecular Biomarker Expression in Response to Chemotherapy in Invasive Ductal Carcinoma

Breast cancer (BC) has varied morphological and biological features and is classified based on molecular and morphological examinations. Molecular classification of BC is based on biological gene-expression profiling. In this study, biomarker modulation was assessed during BC treatment in 30 previously untreated patients. Heterogeneity among patients was pathologically diagnosed and classified into luminal and basal-like immunohistochemical profiles based on estrogen, progesterone, and human epidermal growth factor receptor (ER/PR/HER2) status. Marker heterogeneity was compared with mRNA biomarker expression in patients with BC before and after therapy. Reverse transcription-polymerase chain reaction was performed for molecular characterization. Expression and modulation of biological markers, CK19, hMAM, CEA, MUC, Myc, Ki-67, HER2/neu, ErbB2, and ER, were assessed after treatment, where the expression of the biomarkers CK19, Ki-67, Myc, and CEA was noted to be significantly decreased. Marker expression modulation was determined according to different stages and pathological characteristics of patients; coexpression of three markers (CK19, Ki-67, and Myc) was specifically modulated after therapy. In the histopathologically classified basal-like group, two markers (CK19 and Ki-67) were downregulated and could be considered as diagnostic biomarkers. In conclusion, pathological characteristics and marker variation levels can be evaluated to decide a personalized treatment for patients

Genotype Cluster Analysis in Pathogenic Escherichia coli Isolates Producing Different CDT Types

Diarrheagenic and uropathogenic E. coli types are mainly characterized by the expression of distinctive bacterial virulent factors. stx1, stx2 (Shiga toxins), and cdt (cytolethal distending toxin) genes have been acquired by horizontal gene transfer. Some virulent genes such as espP (serine protease), etpD (part of secretion pathway), and katP (catalase-peroxidase), or sfpA gene (Sfp fimbriae), are on plasmids and the others like fliC (flagellin) and the fimH gene (fimbriae type-I) are located on chromosome. Genomic pathogenicity islands (PAIs) carry some virulent genes such as hly gene. To determine the existence of virulence genes in cdt clinical isolates, genes including stx1, stx2, cdt, hly, espP, katP, sfpA, etpD, fliC, and fimH were assessed by Polymerase Chain Reaction (PCR). The most prevalent isolates for etpD and katP genes were 85.7% in cdtII. katP gene was also observed 83.3% in cdtI. However, in 42.85% of cdtIII isolates, espP gene was the most detected. Moreover, hly gene was also the most prominent gene in cdtIII (71.42%). sfpA gene was observed in 66.6% of cdtV. stx1 gene was detected in 100% of cdtII, cdtIV, and cdtV types. Presence and pattern of virulence genes were considered among cdt positive isotypes and used for their clustering and profiling

Effect of Solvent Polarity on the Extraction Yield of Antioxidants from Lactobacillus Supernatants: Effect of Solvent Polarity on the Antioxidant Extraction

There is increasing evidence to suggest that the Lactobacilli species possess antioxidant activities, however, there are a few reports of optimization of solvent systems for the separation of their antioxidant compounds by thin-layer chromatography. In the current study, we explore the efficiency of four organic solvents (aqueous, methanol, ethyl acetate, and n-hexane) for the extraction of antioxidant materials from Lactobacillus supernatants. According to the results, methanol extraction significantly increased the antioxidant properties of Lactobacillus supernatants. In addition, the methanol extract of Lactobacillus supernatants was fractionated using thin-layer chromatography (TLC). A solvent system consisting of methanol/chloroform is a promising approach for TLC analysis of Lactobacillus supernatant. The partial purification of the antioxidant components using thin-layer chromatography demonstrated a drastic rise in the antibacterial and antioxidant properties in comparison to the crude methanol extract of the same sample. In this study, the TLC fractionation of Lactobacillus extracellular materials was described for the first time. Further isolation and purification are essential to identify these bioactive compounds

Non-Coding CK19 RNA in Peripheral Blood and Tissue of Breast Cancer Patients

Breast carcinoma is the major cause of cancer-related death in women. The incidence of this carcinoma is rising and there are many attempts to decrease this problem. The aim of this study was detection of full-length cytokeratin 19 (CK19) mRNA, in peripheral blood and tissue of breast cancer patients in early stage of cancer. In this study, RT-PCR (reverse transcriptase-polymerase chain reaction) technique was used for detection of CK19 mRNA in peripheral blood and tissue of breast cancer patients. Primers were established to amplify the CK19 as a tumor marker. Moreover, CYFRA 21-1 subunit of CK19 protein was measured in the serum of patients. CK19 mRNA was detected and sequenced. It is shown that the most released CK19 mRNAs in blood and tissue of cancer patients are non-coding RNA. The mutated forms of mRNA are the incomplete transcripts of protein-coding gene as a long non-coding RNA (lncRNA) that could regulate gene expression. Moreover, small non-coding RNA (ncRNA) as fragments of CK19 is mostly observed in this experiment. They may play a role in tumorogenesis and their biologic exact function in breast cancer should be further elucidated