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  • 1
    Publication Date: 2013-08-21
    Description: Mammals harbour a complex gut microbiome, comprising bacteria that confer immunological, metabolic and neurological benefits. Despite advances in sequence-based microbial profiling and myriad studies defining microbiome composition during health and disease, little is known about the molecular processes used by symbiotic bacteria to stably colonize the gastrointestinal tract. We sought to define how mammals assemble and maintain the Bacteroides, one of the most numerically prominent genera of the human microbiome. Here we find that, whereas the gut normally contains hundreds of bacterial species, germ-free mice mono-associated with a single Bacteroides species are resistant to colonization by the same, but not different, species. To identify bacterial mechanisms for species-specific saturable colonization, we devised an in vivo genetic screen and discovered a unique class of polysaccharide utilization loci that is conserved among intestinal Bacteroides. We named this genetic locus the commensal colonization factors (ccf). Deletion of the ccf genes in the model symbiont, Bacteroides fragilis, results in colonization defects in mice and reduced horizontal transmission. The ccf genes of B. fragilis are upregulated during gut colonization, preferentially at the colonic surface. When we visualize microbial biogeography within the colon, B. fragilis penetrates the colonic mucus and resides deep within crypt channels, whereas ccf mutants are defective in crypt association. Notably, the CCF system is required for B. fragilis colonization following microbiome disruption with Citrobacter rodentium infection or antibiotic treatment, suggesting that the niche within colonic crypts represents a reservoir for bacteria to maintain long-term colonization. These findings reveal that intestinal Bacteroides have evolved species-specific physical interactions with the host that mediate stable and resilient gut colonization, and the CCF system represents a novel molecular mechanism for symbiosis.〈br /〉〈br /〉〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3893107/" target="_blank"〉〈img src="https://static.pubmed.gov/portal/portal3rc.fcgi/4089621/img/3977009" border="0"〉〈/a〉   〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3893107/" target="_blank"〉This paper as free author manuscript - peer-reviewed and accepted for publication〈/a〉〈br /〉〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Lee, S Melanie -- Donaldson, Gregory P -- Mikulski, Zbigniew -- Boyajian, Silva -- Ley, Klaus -- Mazmanian, Sarkis K -- DK078938/DK/NIDDK NIH HHS/ -- GM007616/GM/NIGMS NIH HHS/ -- GM099535/GM/NIGMS NIH HHS/ -- P01 DK091222/DK/NIDDK NIH HHS/ -- R01 DK078938/DK/NIDDK NIH HHS/ -- R01 GM099535/GM/NIGMS NIH HHS/ -- R21 DK083633/DK/NIDDK NIH HHS/ -- England -- Nature. 2013 Sep 19;501(7467):426-9. doi: 10.1038/nature12447. Epub 2013 Aug 18.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, California 91125, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/23955152" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; Bacterial Proteins/genetics/metabolism ; Bacteroides/*classification/genetics/growth & development/*physiology ; Bacteroides fragilis/genetics/growth & development/metabolism ; Colon/microbiology ; Conserved Sequence/genetics ; Evolution, Molecular ; Female ; Gastrointestinal Tract/*microbiology ; Gene Deletion ; Genes, Bacterial/genetics ; Germ-Free Life ; Intestinal Mucosa/microbiology ; Male ; Metagenome/*physiology ; Mice ; Polysaccharides/metabolism ; Species Specificity ; Symbiosis/genetics
    Print ISSN: 0028-0836
    Electronic ISSN: 1476-4687
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
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  • 2
    Publication Date: 2016-01-19
    Description: Many procedures in modern clinical medicine rely on the use of electronic implants in treating conditions that range from acute coronary events to traumatic injury. However, standard permanent electronic hardware acts as a nidus for infection: bacteria form biofilms along percutaneous wires, or seed haematogenously, with the potential to migrate within the body and to provoke immune-mediated pathological tissue reactions. The associated surgical retrieval procedures, meanwhile, subject patients to the distress associated with re-operation and expose them to additional complications. Here, we report materials, device architectures, integration strategies, and in vivo demonstrations in rats of implantable, multifunctional silicon sensors for the brain, for which all of the constituent materials naturally resorb via hydrolysis and/or metabolic action, eliminating the need for extraction. Continuous monitoring of intracranial pressure and temperature illustrates functionality essential to the treatment of traumatic brain injury; the measurement performance of our resorbable devices compares favourably with that of non-resorbable clinical standards. In our experiments, insulated percutaneous wires connect to an externally mounted, miniaturized wireless potentiostat for data transmission. In a separate set-up, we connect a sensor to an implanted (but only partially resorbable) data-communication system, proving the principle that there is no need for any percutaneous wiring. The devices can be adapted to sense fluid flow, motion, pH or thermal characteristics, in formats that are compatible with the body's abdomen and extremities, as well as the deep brain, suggesting that the sensors might meet many needs in clinical medicine.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Kang, Seung-Kyun -- Murphy, Rory K J -- Hwang, Suk-Won -- Lee, Seung Min -- Harburg, Daniel V -- Krueger, Neil A -- Shin, Jiho -- Gamble, Paul -- Cheng, Huanyu -- Yu, Sooyoun -- Liu, Zhuangjian -- McCall, Jordan G -- Stephen, Manu -- Ying, Hanze -- Kim, Jeonghyun -- Park, Gayoung -- Webb, R Chad -- Lee, Chi Hwan -- Chung, Sangjin -- Wie, Dae Seung -- Gujar, Amit D -- Vemulapalli, Bharat -- Kim, Albert H -- Lee, Kyung-Mi -- Cheng, Jianjun -- Huang, Younggang -- Lee, Sang Hoon -- Braun, Paul V -- Ray, Wilson Z -- Rogers, John A -- F31MH101956/MH/NIMH NIH HHS/ -- Howard Hughes Medical Institute/ -- England -- Nature. 2016 Feb 4;530(7588):71-6. doi: 10.1038/nature16492. Epub 2016 Jan 18.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Materials Science and Engineering, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA. ; Frederick Seitz Materials Research Laboratory, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA. ; Department of Neurological Surgery, Washington University School of Medicine, St Louis, Missouri 63110, USA. ; KU-KIST Graduate School of Converging Science and Technology, Korea University, Seoul 136-701, Republic of Korea. ; Department of Chemical and Biomolecular Engineering, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA. ; Department of Engineering Science and Mechanics, Materials Research Institute, The Pennsylvania State University, University Park, Pennsylvania 16802, USA. ; Institute of High Performance Computing, Singapore 138632, Singapore. ; Department of Anesthesiology, Washington University School of Medicine, St Louis, Missouri 63110, USA. ; Department of Biomicrosystem Technology, Korea University, Seoul 136-701, South Korea. ; Department of Biochemistry and Molecular Biology, Korea University College of Medicine, Seoul 136-713, South Korea. ; Weldon School of Biomedical Engineering, School of Mechanical Engineering, The Center for Implantable Devices, Birck Nanotechnology Center, Purdue University, West Lafayette, Indiana 47907, USA. ; School of Mechanical Engineering, Purdue University, West Lafayette, Indiana 47907, USA. ; Department of Mechanical Engineering, Civil and Environmental Engineering, Materials Science and Engineering, and Skin Disease Research Center, Northwestern University, Evanston, Illinois 60208, USA. ; Department of Biomedical Engineering, College of Health Science, Korea University, Seoul 136-703, South Korea. ; Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/26779949" target="_blank"〉PubMed〈/a〉
    Keywords: *Absorbable Implants/adverse effects ; Administration, Cutaneous ; Animals ; Body Temperature ; Brain/*metabolism/surgery ; Electronics/*instrumentation ; Equipment Design ; Hydrolysis ; Male ; Monitoring, Physiologic/adverse effects/*instrumentation ; Organ Specificity ; Pressure ; *Prostheses and Implants/adverse effects ; Rats ; Rats, Inbred Lew ; *Silicon ; Telemetry/instrumentation ; Wireless Technology/instrumentation
    Print ISSN: 0028-0836
    Electronic ISSN: 1476-4687
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
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