PROOF 0393-974X (2017) Copyright © by BIOLIFE, s.a.s. This publication and/or article is for individual use only and may not be further reproduced without written permission from the copyright holder. Unauthorized reproduction may result in inancial and other penalties DISCLOSURE: ALL AUTHORS REPORT NO CONFLICTS OF INTEREST RELEVANT TO THIS ARTICLE. 203 Vol. 31, no. 1, xx-xx (2017) JOURNAL OF BIOLOGICAL REGULATORS & HOMEOSTATIC AGENTS PROOF Mailing address: Dr. Angelo Leone, BioNec, Section of Histology and Embriology, School of Medicine, University of Palermo, Via del Vesrpo, 129 - 90127 Palermo, Italy Tel.: +39 0916553581 e-mail: angelo.leone@unipa.it Key words: microbiota, dysbiosis, inlammatory bowel diseases, ingerprint microbiota To the Editor, The human normal lora, or microbiota, is extensive, both in its absolute quantitative mass and in its qualitative diversity. The human intestinal tract hosts about 100 trillion microorganisms with at least 15,000-36,000 bacterial species. The microbiome is THE FINGERPRINT OF THE HUMAN GASTROINTESTINAL TRACT MICROBIOTA: A HYPOTHESIS OF MOLECULAR MAPPING G. TOMASELLO 1-3-4 , M. MAZZOLA 6 , A. JURJUS 2 F. CAPPELLO 1,4 , F. CARINI 4 , P. DAMIANI 3 , A. GERGES GEAGEA 2 , MN. ZEENNY 2 and A. LEONE 5 1 Euro-Mediterranean Institute of Science and Technology (IEMEST), Italy; 2 Department of Anatomy, Cell Biology and Physiology, American University of Beirut, Beirut, Lebanon; 3 Gastroenterology and Endoscopy Unit, Fondazione Istituto S. Raffaele-G. Giglio, Cefalù, Italy; 4 AOUP “P Giaccone”, School of Medicine, University of Palermo, Italy; 5 Department of Experimental Biomedicine and Clinical Neurosciences, Section of Histology, School of Medicine and Surgery, University of Palermo, Italy; 6 Department of Experimental Biomedicine and Clinical Neurosciences, Section of Human Anatomy, School of Medicine and Surgery, University of Palermo, Italy Received June 16, 2016- Accepted February 16, 2017 The precise etiology of Inlammatory Bowel Disease (IDB) remains unclear and several factors are believed to play a role in its development and progression, including the composition of microbial communities resident in the gastrointestinal tract. Human intestinal microbiota are extensive with at least 15,000-36,000 bacterial species. However, thanks to the new development in sequencing and molecular taxonomic methodologies, our understanding of the microbiota population composition, dynamics, and ecology has greatly increased. Intestinal microbiota play a critical role in the maintenance of the host intestinal barrier homeostasis, while dysbiosis, which involves reduction in the microbiome diversity, can lead to progression of inlammatory disorders, such as IBD and colorectal cancer. It is hypothesized that ingerprinting characterization of the microbiota community composition is the irst step in the study of this complex bacterial ecosystem and a crucial step in the targeted therapy. Molecular ingerprinting of human gastrointestinal tract microbiota could be performed by different techniques including the semi quantitation, 16SrRNA, the DNA- microarray as well as other relatively new methods which were developed to study many complex bacterial ecosystems. These techniques provide individual data and proiles, using fast and sensitive tools for the high taxonomic level ingerprint of the human intestinal microbiota and provide estimation of the relative presence of the microbial target groups within each individual. Such personalized information serves as a remarkable and unprecedented opportunity to improve targeted medical treatment and probably develop strategies to prevent disease. LETTER TO THE EDITOR