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Background: Leptospirosis has been recognized as an important reemerging infectious disease caused by pathogenic Leptospira spp. A major challenge of this disease is the application of a basic research to improve diagnostic method. Outer membrane proteins of Leptospira are potential candidates that could be useful in diagnosis. Among them the lipL41 is an immunogenic protein which is present only in pathogenic serovars. In order to evaluate genetic conservation of the lipL41 gene, we cloned and sequenced this gene from Leptospira interrogans serovar Canicola.
Materials and Methods: Following the DNA extraction from the serovar, the lipL41 gene was amplified and cloned into pTZ57R/T vector and transformed into the competent E. coli (Top10). Recombinant clones were confirmed by colony PCR and DNA sequencing. The related sequences were then analyzed and compared with the sequences in the Genbank database.
Results: PCR amplification of the lipL41 gene resulted in a 1065 bp PCR product. The PCR based on the lipL41 gene detected all the pathogenic reference serovars of the tested Leptospira spp. It was revealed that in Iran the homology of the lipL41 gene between vaccinal and clinical serovars of Canicola was 100%. It also showed >95.9% homology with other pathogenic serovars in Genbank database, which indicates genetic conservation of this gene.
Conclusion: Because of the conservation of lipL41 gene among different strains of Leptospira and its exclusive presence in leptospira, it was revealed that the cloned gene could be further used as a good candidate for developing diagnostic methods such as ELISA and as positive control in diagnostic PCR.

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The molecular characteristics of Yersinia ruckeri such as total proteins (TP), outer membrane proteins OMP) and lipopolysaccharides (LPS) in 34 isolates from rainbow trout farms in Tehran, Mazandaran and Zanjan provinces were determined, using SDS-PAGE method. The molecular weight (MW) for TP of all bacterial isolates was mostly less than 100 KD with a banding density in range 28 to 100 KD. Also, protein pattern of OMP consisted of three major bands with MW of 28-35 KD (two bands) and 10-17 KD (one band) plus some minor bands with MW of 48-75 KD and 17-28 KD. In addition, the LPS pattern of all bacterial isolates were less than 130 KD with the most band density in range 28-100 KD. These results show that the banding profile of TP, OMP and LPS of all isolates of Y. ruckeri were identical, demonstrating minimum heterogeneity among Iranian isolates of Y. ruckeri. Therefore, it is feasible for the formulation of a monovalent vaccine to yersiniosis in future.

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Background: Klebsiella pneumoniae (K. pneumoniae) is responsible for life-threatening infections, given that it is usually resistant to antibacterial drugs. Due to the restricted antibiotic options for the treatment of resistant K. pneumoniae infections and the critical role of humoral immune responses in preventing infectious diseases, the present in silico study aimed to investigate fimbriae (type 1 and type 3), outer membrane protein A (OmpA), and outer membrane protein K35 (OmpK35) to find appropriate epitopes for vaccine development.
Materials & Methods: Several independent bioinformatics servers including IEDB, ABCpred, VaxiJen, and EMBOSS were applied to identify appropriate linear epitopes (B-cell and T-cell).  Conformational epitopes were also predicted using Ellipro and Discotope programs. The Antigenic Peptide Prediction server was used to confirm the identified epitopes. Molecular characteristics, toxicity, human similarity, and allergenicity were investigated.
Findings: The results demonstrated that the investigated proteins were highly immunogenic. In the first step, 25 epitopes were identified in the investigated proteins. After applying different exclusion criteria, the final epitope of each investigated protein was selected. The final epitopes of fimbriae (type 1 and type 3), OmpK35 and OmpA were located in 28-49, 26-53, 271-291, and 288-299 regions, respectively. Allergenicity, toxicity, and human similarity were negative for the predicted epitopes.
Conclusion: The present study results introduced four reliable B-cell and T-cell epitopes (each for one investigated protein) with appropriate physicochemical characteristics. The proposed epitopes could be used in vaccine development against K. pneumoniae after further in vitro and in vivo studies.

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Objectives: Acinetobacter baumannii is a Gram-negative, non-motile aerobic bacterium known as a nosocomial pathogen resisting often to broad range of antibiotics. The pathogen is a serious agent of mortality and morbidity in hospital particularly among immunocompromise patients. Treatment and control of its infections is complicated owing to its high antibiotic resistance, survival in various environmental conditions and utilization of wide range of nutrient sources. Early detection of the pathogen in established infections is pivotal for controlling the infections. Culture and biochemical test are current methods for detection of the bacterium taking 2-5 days time. Hence, a new rapid specific affordable diagnostic test is needed. Development of such test depends on a suitable biomarker without any cross reactivity with other bacteria. Methods: Accordingly, aim of the study is to unveil of a 34.4 KDa outer membrane protein (OMP) introduced by Islam et al. in A. baumannii ATCC19606. In the current study, we harnessed various bioinformatic servers to screen whole proteome of the bacterium. Properties critical to the screening include: molecular weight, localization, topology, homology, antigenicity and allergenicity of proteins. Results: Three proteins were found as suitable candidate molecular weight as well as localization points of view. BLAST searches, antigen probability predictions and other analyses led to selection of one protein as the best specific antigen of A. baumannii. Conclusion: The in silico analyses unveiled the best candidate protein vide accession number ZP_05827218.1.