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HMGB1 protein is an intracellular protein that translocated into the nucleus and regulates genes expression. HMGB1 plays multi-functional roles through recombination, transcriptional regulation, and inflammation. HMGB1 binds to cyclin-dependent kinase such as CDK2 that regulates the transcription of genes associated with the progression of cell cycle. In addition, HMGB1 as a novel cytokine plays major role in inflammation and arthritis. Recently, the role of HMGB1 protein as an adjuvant and stimulating both humoral and cellular immune responses has been proven in viral infections such as HIV-1 and influenza. Several studies indicated that Hp91, a HMGB1-derived peptide, stimulates efficiently DC maturation, and boosts the cellular and humoral immune responses in vivo. Our recent data also showed that the full length of HMGB1 gene, and Hp91 peptide could be an effective adjuvant in developing the therapeutic HPV DNA- and protein-based vaccines, respectively. In this review, the structure and functions of HMGB1 is described in molecular biology and medicine.

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Aim and Background: Bacterial arthritis is one of the arthritis diseases known that can rapidly cause joint damage. Among the bacteria causing septic arthritis, Mycobacterium tuberculosis (MTB) is one of those that rarely produce arthritis. The aim of this study is to examine the presence of MTB in synovial fluid of patients with arthritis using Polymerase Chain Reaction (PCR)
Materials and Methods: This study was carried out on 70 synovial fluid samples gathered from Shariati Hospital. DNA was extracted using Phenol-Chloroform standard extraction technique. PCR test optimized on the basis of IS6110 target gene. Samples were analyzed by PCR test after evaluation of specificity and sensitivity of PCR.
RESULT: PCR test was optimized and the 317-bp amplicon detected by 1.5% agarose gel electrophoresis. Limit of detection (LOD) was estimated as 100 copy/Reaction. MTB DNA was detected in 4 (5.7%) synovial fluid samples of patients with arthritis.
CONLUSION: First step in treatment is rapid and accurate diagnosis. MTB have some characteristics including slow generation making the identification difficult and exhausting through culturing and biochemical tests that sometimes leads to ambiguous results. Results of this study confirm that MTB could play a role in bacterial arthritis and rapid diagnosis using PCR provides us with accurate treatment.

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Today, using genetic engineering, recombinant proteins can be produced in large volumes, desirable quality and low cost to meet the demands of different industries. The recombinant proteins can be expressed in various expression methods such as cell-free expression systems or prokaryotic or eukaryotic cells. Considering the advantages of using prokaryotic cells, one of the commonly used systems for the production of recombinant proteins is the cultivation of Escherichia coli (E. coli). The aim of the present study was to evaluate the expression of recombinant protein in E. coli and provide a suitable methods for achieving high cell density and maximal expression capability. Hence, by studying about 63 published articles in the field of genetic engineering, various expression systems were introduced for recombinant proteins production. In spite of many advantages and vast applications for this method of recombinant protein production, its use may include problems such as false folding, production of aggregated proteins and the absence of expression of soluble and active ones. Several approaches have been developed to increase the efficiency and solubility; change in the rate of synthesis of proteins, use of binding proteins, mutations in the target protein, simultaneous expression of molecular chaperones and optimization of culture conditions, are among different methods which is evaluated in this study. Virtual cloning has come into the context of developing more advanced software tools and databases and has been able to eliminate the limitations of recombinant expression of proteins in hosts with a different expression system.