Due to the wide application of silver-containing dressings and silver-coated medical devices in clinical treatment; the extensive use of antibacterial agents and heavy metal agents in feed factories, Escherichia coli has formed the tolerance to silver ions. To systematically understand the known silver ion resistance mechanisms of E. coli, this article reviews the complex regulatory network and various physiological mechanisms of silver ion tolerance in E. coli, including the regulation of outer membrane porins, energy metabolism modulation, the role of efflux systems, motility regulation, and silver ion reduction. E. coli reduces the influx of silver ions by missing or mutating outer membrane porins such as OmpR, OmpC, and OmpF. It adapts to high concentrations of silver ions by altering the expression of ArcA/B and enhances the efflux capacity of silver ions under high-concentration silver stress via the endogenous Cus system and exogenous Sil system. Furthermore, the motility of bacteria is related to silver tolerance. E. coli has the ability to reduce silver ions, thereby alleviating the oxidative stress induced by silver ions. These findings provide a new perspective for understanding the formation and spread of bacterial tolerance and provide directions for the development of next-generation silver-based antimicrobials and therapies.
Escherichia coli/genetics* ; Silver/pharmacology* ; Drug Resistance, Bacterial ; Anti-Bacterial Agents/pharmacology* ; Porins/metabolism*

O ⁶-carboxymethyl guanine(O ⁶-CMG) is a highly mutagenic alkylation product of DNA that causes gastrointestinal cancer in organisms. Existing studies used mutant Mycobacterium smegmatis porin A (MspA) nanopore assisted by Phi29 DNA polymerase to localize it. Recently, machine learning technology has been widely used in the analysis of nanopore sequencing data. But the machine learning always need a large number of data labels that have brought extra work burden to researchers, which greatly affects its practicability. Accordingly, this paper proposes a nano-Unsupervised-Deep-Learning method (nano-UDL) based on an unsupervised clustering algorithm to identify methylation events in nanopore data automatically. Specially, nano-UDL first uses the deep AutoEncoder to extract features from the nanopore dataset and then applies the MeanShift clustering algorithm to classify data. Besides, nano-UDL can extract the optimal features for clustering by joint optimizing the clustering loss and reconstruction loss. Experimental results demonstrate that nano-UDL has relatively accurate recognition accuracy on the O ⁶-CMG dataset and can accurately identify all sequence segments containing O ⁶-CMG. In order to further verify the robustness of nano-UDL, hyperparameter sensitivity verification and ablation experiments were carried out in this paper. Using machine learning to analyze nanopore data can effectively reduce the additional cost of manual data analysis, which is significant for many biological studies, including genome sequencing.
Deep Learning ; Guanine ; Nanopore Sequencing ; Nanopores ; Porins/genetics*

Objective: To study the polymorphism in P66 and its human B-cell epitopes of Methods: Polymerase chain reaction (PCR) and sequencing were used to obtain the P66 sequences of 59 Chinese Results: Results showed that genetic and amino acid diversity presented in the 66 kD protein of all 59 Chinese strains, especially in Conclusion In P66 of 59 Chinese strains, polymorphisms were widely distributed. More importantly, the P66 amino acid sequences of
Bacterial Proteins/genetics* ; Borrelia burgdorferi/genetics* ; China ; Cluster Analysis ; Epitopes, B-Lymphocyte/genetics* ; Genetic Markers ; Genotype ; Humans ; Mutation ; Polymerase Chain Reaction ; Polymorphism, Genetic ; Porins/genetics*

Bacterial Outer Membrane Proteins ; chemistry ; genetics ; metabolism ; Escherichia coli Proteins ; chemistry ; genetics ; metabolism ; Glutamic Acid ; genetics ; metabolism ; Histidine ; genetics ; Hydrogen-Ion Concentration ; Ion Channel Gating ; genetics ; Lipid Bilayers ; metabolism ; Mutant Proteins ; chemistry ; genetics ; metabolism ; Mutation ; Porins ; chemistry ; genetics ; metabolism

OBJECTIVETo explore the role of ompT gene in uropathogenic E. coli (UPEC) CFT073 strain in urinary tract infection (UTI).

METHODSAn ompT deletion mutant (COTD) was generated by λ Red recombineering in the UPEC CFT073 strain, which was characterized by PCR and sequencing. C57B/L6 mouse models of acute UTI with the mutant and wild-type strains were established to compare the colonization abilities of the two strains in the bladder. The adhesion of CFT073 mutant to human unthelial 5637 cells was also investigated in vitro.

RESULTSPCR and DNA sequencing confirmed the loss of ompT gene in the mutant COTD. The in vitro adhesion rate of the mutant strain COTD to 5637 cells was (6.7±2.2)%, significantly lower than that of (8.3±1.9)% of the wild-type strain (P<0.05). In the murine models of acute UTI, the mutant strain showed a mean colonization number of about (17±8)×10⁴ cfu, which was significantly lower than that of (7∓2)×10⁵ cfu of the wide-type CFT073 strain (P<0.05).

CONCLUSIONOmpT gene can be involved in the colonization of UPEC in the bladder tissue and plays an important role in the pathogenesis of UPEC-induced UTI.

Animals ; Bacterial Proteins ; genetics ; Cell Line ; Escherichia coli Infections ; microbiology ; Escherichia coli Proteins ; genetics ; Gene Knockout Techniques ; Humans ; Mice ; Mice, Inbred C57BL ; Porins ; genetics ; Urinary Tract Infections ; microbiology ; Uropathogenic Escherichia coli ; genetics

OBJECTIVETo construct a fused expression vector of the outer membrane protein gene PorB of Neisseria gonorrhoeae, express the fusion protein in the prokaryotic system, and obtain a gene recombination protein, for the purpose of preparing the ground for further research on the pathopoiesis and immune protective response of PorB.

METHODSA pair of primers were designed according to the known sequence of the PorB gene, and the PorB gene was amplified by PCR from the genome of Neisseria gonorrhoeae 29403 and cloned into the prokaryotic expression plasmid pGEX-4T-1 to generate pGEX-4T-PorB recombinants. The recombinant plasmid pGEX4T-PorB was transferred into competent cells E. coli BL21. After confirmed by restriction endonuclease digestion, PCR and DNA sequencing analysis, the recombinant protein was induced to express by isopropyl-beta-D-thiogalactoside (IPTG), and examined by SDS-PAGE and Western blotting.

RESULTSRestriction endonuclease digestion, PCR amplification and DNA sequencing analysis showed that the PorB gene of 1 047 bp was amplified from Neisseria gonorrhoeae DNA, and the recombinant plasmid pGEX-4T-PorB was successfully constructed and highly expressed in E. coli.

CONCLUSIONThe prokaryotic expression vector of pGEX-4T-PorB was successfully constructed and efficiently expressed in the prokaryotic system, which has provided a basis for further study on the biological activity of the PorB protein, as well as animal immune experiment and detection of Neisseria gonorrhoeae, and its application as a mucosal immune vaccine.

Bacterial Outer Membrane Proteins ; genetics ; metabolism ; Cloning, Molecular ; Escherichia coli ; metabolism ; Gene Expression ; Genetic Vectors ; Molecular Sequence Data ; Neisseria gonorrhoeae ; genetics ; metabolism ; Plasmids ; Porins ; genetics ; metabolism

OBJECTIVETo construct a recombinant eukaryotic expression plasmid pcDNA3.1-Ct MOMP168 including Ct MOMP multi-epitopes gene, and evaluate the Ct MOMP-specific humoral and cellular immune response induced by pcDNA3.1-Ct MOMP168 in BALB/c mice.

METHODSRecombinant plasmid pcDNA3.1-Ct MOMP168 including Ct MOMP multi-epitopes gene was constructed. Then, BALB/c mice were randomly assigned to receive (intramuscular injection) either pcDNA3.1-Ct MOMP168 or pcDNA3.1 or PBS (n = 12, 100 microg/time per mouse), and the same immunization schedule was repeated for the third time at 2 week intervals. The titers of anti-Ct MOMP antibody and its antibody subtypes in sera, the cytotoxicity of Ct MOMP-specific cytotoxic T lymphocyte (CTL) in spleen, and the level of cytokine (IFN-gamma, IL-4, IL-10)-producing CD3(+) T cells in spleen were detected by ELISA, LDH release assays and intracellular cytokine staining-fluorescence activated cell sorter (ICS-FACS), respectively.

RESULTSThe recombinant plasmid pcDNA3.1-Ct MOMP168 was able to induce Ct-specific antibody response (A(490) = 0.973 +/- 0.136; serum titer was 1:1000) as compared with pcDNA3.1 (A(490) = 0.180 +/- 0.025) and PBS (A(490) = 0.110 +/- 0.015), and the major antibody subtype was IgG2a with statistical significance (F = 106.884, P < 0.05). When the ratio of effector cells and target cells reached to 50:1, the activity of cytotoxic T-lymphocyte in pcDNA3.1-Ct MOMP168 immunized mice (41.71% +/- 8.34%) was significantly higher (F = 22.315, P < 0.05) than that in pcDNA3.1 immunized mice (18.40% +/- 3.45%) and PBS immunized mice (14.50% +/- 2.42%). The levels of CD3(+) IFN-gamma(+) T cells in pcDNA3.1-Ct MOMP168 immunized mice (1.15% +/- 0.16%) were significantly higher (F = 99.638, P < 0.05) than that in pcDNA3.1 immunized mice (0.12% +/- 0.08%) and PBS immunized mice (0.09% +/- 0.03%), while the significant difference in the levels of IL-4(+) CD3(+) T cells and IL-10(+) CD3(+) T cells was not observed (F = 0.886 and 1.112, P > 0.05) between pcDNA3.1-Ct MOMP168 immunized mice (0.13% +/- 0.08% and 0.14% +/- 0.08%) and pcDNA3.1 (0.07% +/- 0.05% and 0.13% +/- 0.06%) or PBS immunized mice (0.08% +/- 0.04% and 0.07% +/- 0.04%).

CONCLUSIONIn BALB/c mice, the recombinant plasmid pcDNA3.1-Ct MOMP168 might induce not only the generation of Ct-specific antibody, but also the high level of Ct MOMP-specific CD3(+) IFN-gamma(+) T cells.

Animals ; Bacterial Outer Membrane Proteins ; genetics ; immunology ; Bacterial Vaccines ; immunology ; Chlamydia trachomatis ; genetics ; immunology ; Immunization ; Male ; Mice ; Mice, Inbred BALB C ; Porins ; genetics ; immunology ; T-Lymphocytes, Cytotoxic ; immunology

In order to amplify pilA gene and ompC gene of avian pathogenic Escherichia coli (APEC) strain, two pairs of primers were designed according to the GenBank sequences, and a 549 bp pilA gene and a 1104 bp ompC gene were obtained by PCR separately. Sequence analysis indicated that the homology of the nucleotide sequence of AEPC strain to those other reference strains was 98.18% of the pilA gene and 97.28% of the ompC gene. Two expression plasmids pETpilA and pETompC were constructed by inserting pilA gene and ompC gene into the prokaryotic expression vector pET-28a. The two plasmids were transformated into E. coli BL21 separately and two recombinant strains BL21 (pETpilA) and BL21 (pETompC) were obtained. The type 1 fimbraie and the out membrane protein were highly expressed when the recombinant strain BL21 (pETpilA) and BL21 (pETompC) were induced by IPTG Two specific proteins were detected by SDS-PAGE and immunogenicity of the expressed protein was confirmed by Western blotting and ELISA. The expressed fimbraie and OmpC were transformed into vaccine. The protective immune response was proved after the mice were immunized with the two vaccines. The results showed that the recombinant strain BL21 (pETpilA) and BL21 (pETompC) could be as candidate vaccine to provide protective immune response against AEPC infection.
Animals ; Cloning, Molecular ; Escherichia coli ; genetics ; immunology ; metabolism ; Escherichia coli Proteins ; genetics ; immunology ; metabolism ; Escherichia coli Vaccines ; immunology ; Fimbriae Proteins ; genetics ; immunology ; metabolism ; Gene Expression Regulation, Bacterial ; Genes, Bacterial ; Mice ; Porins ; genetics ; immunology ; metabolism ; Recombinant Fusion Proteins ; genetics ; immunology ; metabolism

Bacterial Proteins ; pharmacology ; Blotting, Western ; Humans ; Immunohistochemistry ; methods ; Interleukin-8 ; genetics ; metabolism ; Internal Fixators ; Lung ; cytology ; drug effects ; Lung Diseases ; microbiology ; Pharmaceutical Solutions ; pharmacology ; Porins ; pharmacology ; RNA, Messenger ; analysis ; Reverse Transcriptase Polymerase Chain Reaction ; Solutions ; chemistry

OBJECTIVETo investigate the blockness effects of purified polyclonal anti-porin I antibody on N. gonorrhoeae adherence to genitourinary tract epithelia of BALB/c mouse.

METHODSPolyclonal anti GST-PI antibody was generated by immunizing rabbit with GST-PI fusion protein which was constructed and expressed by ourselves. The purified immunoglobulin G was obtained by ammonium sulphate deposition and DEAE cellulose chromatography. Mice model of gonorrhea was established. In order to evaluate the effects of PI-IgG on gonococcus adhesion to vagina mucus, the macroscopic and pathological assessing as well as gonococcus culture was employed after gonococcus challenge on PI-IgG immunized mice.

RESULTNo pus and pathological inflammation were observed on mice vagina mucus treated with 1 mg/ml PI-IgG 3 hours before gonococcus challenge. Gonococcus could not be detected in the smears and washing solutions from vagina. Pathological inflammation was found in mice treated with anti PI-IgG, in which the concentrations were lower than 1 mg/ml or the treated time was longer than 3 hours prior to gonococcus challenge.

CONCLUSIONThe purified anti PI-IgG can effectively inhibit the adherence and infection of gonococci to genitourinary tract epithelia of BALB/c mice. In addition, the blocking duration of anti PI-IgG is associated with antibody concentration.

Animals ; Antibodies, Monoclonal ; pharmacology ; Bacterial Adhesion ; drug effects ; Epithelium ; drug effects ; microbiology ; Female ; Glutathione Transferase ; biosynthesis ; genetics ; Gonorrhea ; microbiology ; prevention & control ; Mice ; Mice, Inbred BALB C ; Neisseria gonorrhoeae ; drug effects ; physiology ; Porins ; biosynthesis ; genetics ; immunology ; Rabbits ; Recombinant Fusion Proteins ; biosynthesis ; genetics ; immunology ; Urogenital System ; drug effects ; microbiology