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Background and purpose: Polymerase chain reaction (PÇR) is a rather quick and accurate method employed for gene detection and isolation. Primer designing is an important issue in this technique and plays a critical role in considering both the genome properties and cloning of the isolated genes. Streptomycin antibiotic is produced by Streptomyces griseus using str gene cluster with more than 25 genes. This gene cluster contains StrR gene encoding a specific protein regulator of this cluster. The pathway specific transcriptional activator then induces transcription of other genes in the str gene cluster. Ïn this study, the researchers aimed at isolating promoterless StrR2 gene and then cloning it.
Materials and methods: To isolate promoterless StrR gene, a set of primers (StrR2) was designed. Ône pair of these primers (St Nes) detected the StrR from the genome. Moreover, Nested-PÇR was then used to detect amplified StrR2 gene. Sites for BamHÏ and XbaÏ were designed in other primers (Str nP1and Str nP2). These primers not only amplified the StrR2 gene but also created restriction enzyme sites in the amplified fragments.
Results: Üsing PÇR, the promoterless StrR2 gene was amplified and its structure was confirmed. This gene was successfully cloned, too. The correct structure of the recombinant plasmids was confirmed using different techniques such as gel electrophoresis, PÇR and restriction digestion analysis.
Çonclusion: Üsing this vector, one can subclone the promoterless StrR2 gene in the Streptomyces expression vectors containing inducible promoters.

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Alloimunization reduces RBCs lifespan in circulation. Identification of phenotypes of RBCs could be helpful in reducing the rate of alloimunization. But often, due to persistence of donor RBC`s in patients circulation, precise identification of blood group antigens in multi transfusion patient would be difficult. Today, DNA technology increased our knowledge in recognizing the molecular basis of blood group antigens. This knowledge helps in predicting profiles of blood groups in patients and overcoming problems of agglutination method. But theoretically, it seems, because of contamination of donor`s WBCs in patients circulation and possibility of their contamination with patient`s WBCs, application of molecular method by WBCs may not be reliable. However, some studies showed that using patient's WBCs can infinitively be applicable in identification of polymorphism of blood group antigens by molecular methods, even in newly transfused patients.

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Background and purpose: Endothelial growth factor type b with anti-angiogenic activity and inhibition of tumor growth are considered as new anticancer drugs. The aim of this research was to study the expression of vegf111b in HEK293 human cells.

Materials and methods: In this experimental study, HEK293 cells were transfected by pBUD.VEGF111b vector containing the VEGF111B gene through lipofectamine method. The mRNA of transfected cells and control cells were extracted and cDNA was built over it. Then, the expression levels of vegf111b were measured using Real time- PCR.

Results: Transfection of HEK293 cells was successfully done and 48 hours after transfection of HEK293 cells, ct of the vegf111b expression in transfected cells was 23.17 and ct of the GAPDH control gene expression in these cells was 21.11. In the control (untransfected) cells the ct of GAPDH was 21.09 and there was no expression of vegf111b in these cells.

Conclusion: Expression of Vegf111b recombinant protein in HEK293 cells is the first step for further research on this protein. Current study has provided the possibility of using this product for future research on angiogenesis and cancer treatments.

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 Background and purpose: Neural circuits and neurotransmitter systems within the basolateral amygdala (BLA) play roles in forming emotional memory through communication with the hippocampus. Therefore, in this study, the role of these neural circuits on synaptic plasticity was investigated by agonist injection of beta-adrenergic receptors into the BLA.
Materials and methods: In this experimental study, the electrophysiological recording from the hippocampus was investigated. Male Wistar rats (210-250 gr) were divided into two groups: control group that received saline (0.5 μl) and the treatment group that received clenbuterol (10 ng/0.5μl). Clenbuterol was also bilaterally injected into the BLA. Then, we studied the effect of clenbuterol on basal activity of the granular cells of the dentate gyrus (DG). Afterwards, a 200-Hz high-frequency stimulation protocol was applied to induce long-term potentiation (LTP). The amplitude of the population spike (PS) and the slope of the excitatory post synaptic potential (EPSP) were analyzed before and after the injection of clenbuterol.
Results: Injection of clenbuterol (10 ng) did not increase PS of the LTP compared to the control group in the DG region. Also, no significant increase was seen in the slope of EPSP in treatment group compared to the control group (P>0.05).
Conclusion: Clenbuterol administration into the basolateral amygdala (10 ng/0.5μl) did not affect basal electrical activity and synaptic reinforcement of the dentate granular cells in 90 minutes

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 Background and purpose: Methicillin-resistant Staphylococcus aureus (MRSA) is one of the major hospital and non-hospital pathogens in children. This meta-analysis and systematic review aimed at exploring the data on prevalence of MRSA in Iranian children.
Materials and methods: Primary articles in English and Persian were searched using the following keywords: prevalence, children, methicillin-resistant staphylococcus aureus (MRSA), and Iran. Electronic databases, including Pubmed, Web of Science, Google Scholar and Iranian databases such as Magiran and SID were searched for articles published in 2007-2019. Qualitative assessment of studies was done using STROBE checklist and data analysis was done in STSTA V11.
Results: A total of 55 articles were identified and 23 met the study inclusion criteria. The prevalence of MRSA in children with S. aureus infection was 22%. The prevalence of community acquired and nosocomial MRSA was 17% and 38%, respectively.
Conclusion: The current meta-analysis showed considerable rates of nosocomial and community acquired MRSA infections among children in Iran. So, pediatricians should consider this issue in empirical treatment.