fa تحقيقي Original Paper <div><strong>ABSTRACT</strong><br> &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; <strong>Background and Objective: </strong>Nanobacteria are nanometer-scale particles with different shapes, which have been a subject of debate in modern microbiology. They belong to a proposed class of living organisms, specifically cell-walled microorganisms with a size much smaller than the generally accepted lower limit for life. Since some microorganisms are able to continue growth at high temperatures, we aimed to isolate thermophilic bacteria from Gheinarcheh hot spring in Ardabil (Iran) and identify the characteristics of these microorganisms<span dir="RTL">.</span><br> <strong>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; Methods:</strong> Microbial mats were found in cultures from Gheinarcheh hot spring in North West of Iran. Synthetic media were prepared and used for isolation of protease-producing thermophilic bacteria, and identification of the features of microbial mats. Cultures were incubated at temperature range of 60-120 oC. Scanning electron microscopy, DNA extraction and polymerase chain reaction were used to further identify characteristics of the microbial biofilms<span dir="RTL">.</span><br> &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; <strong>Results:</strong> Microbial biofilms of nanoparticles were detected in our samples. Growth of the bacteria increased at all temperatures tested. Results of scanning electron microscopy showed nano-sized particles in the scale of 60 nm. No band was visible in gel electrophoresis of polymerase chain reaction products<span dir="RTL">.</span><br> Conclusion: This study is the first to report the presence of hyperthermophilic nanobacteria in Iran<span dir="RTL">.</span><br> &nbsp;&nbsp;&nbsp;&nbsp;&nbsp; <strong>Keywords:</strong> Nanobacteria, Hyperthermophile, Microbial Mat.</div> Nanobacteria, Hyperthermophile, Microbial Mat. 20 24 http://mlj.goums.ac.ir/browse.php?a_code=A-10-1-473&slc_lang=fa&sid=1 Reza Habibipour Habibipour@iauh.ac.ir 100319475328460012550 100319475328460012550 Yes Department of Microbiology, College of Basic Sciences, Hamedan Branch, Islamic Azad University, Hamedan, Iran Gholamreza Zarrini 100319475328460012551 100319475328460012551 No Department of Microbiology, College of BasicSciences, Tabriz University, Tabriz, Iran Shohreh Yarizadeh 100319475328460012552 100319475328460012552 No Department of Microbiology, College of Basic Sciences, Tabriz University, Tabriz, Iran Department of Microbiology, College of Basic Sciences, Hamedan Branch, Islamic Azad University, Hamedan, Iran