{"604640":{"#nid":"604640","#data":{"type":"news","title":"In zebrafish, the cholera bacterium sets off a surprising flush","body":[{"value":"\u003Cp\u003EResearchers experimenting with live zebrafish witnessed a 200% increase in the strength of intestinal contractions soon after the organisms were exposed to the cholera-causing bacterium \u003Cem\u003EVibrio cholerae\u003C\/em\u003E. The strong contractions led to expulsion of native gut bacteria\u003Cem\u003E.\u003C\/em\u003E\u003C\/p\u003E\r\n\r\n\u003Cp\u003EThe discovery, detailed in the \u003Ca href=\u0022http:\/\/www.pnas.org\/content\/early\/2018\/03\/29\/1720133115\u0022\u003E\u003Cem\u003EProceedings of the National Academy of Sciences\u003C\/em\u003E\u003C\/a\u003E, \u0026ldquo;was remarkable and unexpected,\u0026rdquo; the authors write.\u003C\/p\u003E\r\n\r\n\u003Cp\u003EThe researchers \u0026ndash; from the University of Oregon, Georgia Institute of Technology, and Memorial-Sloan Kettering Cancer Center \u0026ndash; used genetic manipulation and cutting-edge three-dimensional microscopy to monitor what happens when the disease-causing microbe is initially introduced into the larvae of zebrafish, an organism commonly studied as a model for understanding health and disease in vertebrates, including humans.\u003C\/p\u003E\r\n\r\n\u003Cp\u003EThe multidisciplinary team of physicists, molecular biologists, and microbiologists focused on the harpoon-like injection capabilities of the type VI secretion system. This appendage, found in many bacteria including \u003Cem\u003EVibrio cholerae, \u003C\/em\u003Etransfers toxic proteins into competing healthy cells.\u003C\/p\u003E\r\n\r\n\u003Cp\u003EThe scientists engineered \u003Cem\u003EVibrio cholerae\u003C\/em\u003E mutants with variations in that secretion system and then observed the behavior of the microbes as they invaded zebrafish colonized with \u003Cem\u003EAeromonas veronii\u003C\/em\u003E, a native species in that animal\u0026rsquo;s gut.\u003C\/p\u003E\r\n\r\n\u003Cp\u003E\u003Cstrong\u003ESWIFT ACTION\u003C\/strong\u003E\u003Cbr \/\u003E\r\nInstead of simply killing native \u003Cem\u003EAeromonas \u003C\/em\u003Egut bacteria upon contact, as expected, when \u003Cem\u003EVibrio cholerae\u003C\/em\u003E entered the gut the native bacteria were swiftly flushed out.\u003C\/p\u003E\r\n\r\n\u003Cp\u003E\u0026ldquo;The secretion system induced dramatic increases in the strength of the peristalsis process, the contractions that move gut contents down the gastrointestinal tract much like squeezing a tube of toothpaste from the end to the top,\u0026rdquo; says coauthor \u003Ca href=\u0022http:\/\/biosci.gatech.edu\/people\/brian-hammer\u0022\u003EBrian K. Hammer\u003C\/a\u003E, a microbiologist and associate professor in the School of Biological Sciences at Georgia Tech.\u003C\/p\u003E\r\n\r\n\u003Cp\u003EThe researchers hypothesized that the unexpected bacterial manipulation in the digestive system might be driven by a particular piece of the type VI machinery known to bind to actin, a cellular scaffolding protein. When the scientists deleted the actin-binding domain from the bacterial gene, they saw that \u003Cem\u003EVibrio cholerae\u003C\/em\u003E lost its ability to enhance peristalsis and its ability to expel native \u003Cem\u003EAeromonas\u003C\/em\u003E.\u003C\/p\u003E\r\n\r\n\u003Cp\u003EThe findings shed new light on how the waterborne \u003Cem\u003EVibrio cholerae \u003C\/em\u003Efunctions. According to the Centers for Disease Control and Prevention, \u003Cem\u003EVibrio cholerae \u003C\/em\u003Etriggers more than 3 million cases of acute diarrheal illness and 100,000 deaths in people worldwide each year.\u003C\/p\u003E\r\n\r\n\u003Cp\u003E\u0026ldquo;Knowing the strategies by which the bacterium is able to invade the intestine can open doors to therapies that might disrupt these paths,\u0026rdquo; says corresponding author \u003Ca href=\u0022https:\/\/physics.uoregon.edu\/profile\/raghu\/\u0022\u003ERaghuveer Parthasarathy\u003C\/a\u003E, a professor of physics at the University of Oregon, whose imaging and analysis techniques were used in the study.\u003C\/p\u003E\r\n\r\n\u003Cp\u003EBecause the type VI secretion system is also found in native gut bacteria, including those in the human gut microbiome, it could be harnessed for therapies, including specially designed probiotics, to promote beneficial species or to defend against disease invasion, Hammer says.\u003C\/p\u003E\r\n\r\n\u003Cp\u003E\u0026ldquo;We suspect that other gut microbes, both pathogenic and beneficial, might similarly make use of this secretion system to reshape their environment,\u0026rdquo; Parthasarathy says.\u003C\/p\u003E\r\n\r\n\u003Cp\u003EMost previous research on this secretion system has relied on studying bacteria outside of animals \u0026ndash; on a Petri dish for example, or by examining fecal samples \u0026ndash; to infer what is happening in the gut during infection.\u003C\/p\u003E\r\n\r\n\u003Cp\u003EWhile the research team captured the impact of invasion by\u003Cem\u003E Vibrio cholerae\u003C\/em\u003E, understanding just how it takes root in the host, such as what specific cells in the animal are targeted, is an open question, Parthasarathy says.\u003C\/p\u003E\r\n\r\n\u003Cp\u003E\u0026ldquo;We still have no idea how the action of his secretion system\u0026rsquo;s harpoon is causing the changes in the muscle contractions,\u0026rdquo; Hammer says. \u0026ldquo;We suspect that what we are observing may be an immune response to irritation in the gut lining. But what cells in the gut are being poked?\u0026rdquo;\u003C\/p\u003E\r\n\r\n\u003Cp\u003EHow the findings may reflect the colonization of \u003Cem\u003EVibrio cholerae\u003C\/em\u003E in humans is not known, but the role of the secretion system makes a similar result plausible, the researchers wrote in their conclusion.\u003C\/p\u003E\r\n\r\n\u003Cp\u003E\u003Cstrong\u003EBIRTH OF COLLABORATION\u003C\/strong\u003E\u003Cbr \/\u003E\r\nThe findings emerged from a collaboration born in 2015 when Hammer, Parthasarathy, and coauthor \u003Ca href=\u0022https:\/\/www.mskcc.org\/research-areas\/labs\/joao-xavier\u0022\u003EJoao Xavier\u003C\/a\u003E, a researcher at the Memorial Sloan-Kettering Cancer Center, discussed joint research possibilities during a conference, \u003Cem\u003EScialog: Molecules Come to Life\u003C\/em\u003E, in Tucson, Arizona.\u003C\/p\u003E\r\n\r\n\u003Cp\u003EThe Scialog (Science and Dialog) was organized by the Research Corporation for Science Advancement and sponsored jointly with the Gordon and Betty Moore Foundation, with additional support from the Simons Foundation. The goal of Scialog is to rapidly catalyze new interdisciplinary collaborative teams, such as the one formed by Hammer, Parthasarathy, and Xavier, to work on high-risk, high-reward projects.\u0026nbsp;\u003C\/p\u003E\r\n\r\n\u003Cp\u003EAs a result, their \u003Ca href=\u0022http:\/\/biosci.gatech.edu\/news-events\/news\/112\u0022\u003Ethree labs received an award\u003C\/a\u003E from the Gordon and Betty Moore Foundation and the Simons Foundation to pursue their Scialog idea. The National Science Foundation, National Institutes of Health, M.J. Murdock Charitable Trust, and Kavli Microbiome Ideas Challenge also supported the research.\u003C\/p\u003E\r\n\r\n\u003Cp\u003E\u003Cstrong\u003EPHOTO CAPTION\u003C\/strong\u003E\u003Cbr \/\u003E\r\nTrajectories of \u003Cem\u003EVibrio cholerae\u003C\/em\u003E bacteria (blue) swimming inside the gut of a larval zebrafish. The gut is visible as a gray background. The total duration of the movie that was \u0026ldquo;squashed\u0026rdquo; into this image is 3.5 seconds, and the total image width is about 0.3 mm. (Courtesy of \u003Ca href=\u0022https:\/\/physics.uoregon.edu\/profile\/raghu\/\u0022\u003ERaghuveer Parthasarathy\u003C\/a\u003E)\u003C\/p\u003E\r\n","summary":null,"format":"limited_html"}],"field_subtitle":[{"value":"Researchers unveil the possible mechanics of a cholera invasion of a host"}],"field_summary":[{"value":"\u003Cp\u003EResearchers experimenting with live zebrafish witnessed a 200% increase in the strength of intestinal contractions soon after the organisms were exposed to the cholera-causing bacterium \u003Cem\u003EVibrio cholerae\u003C\/em\u003E. The strong contractions led to expulsion of native gut bacteria\u003Cem\u003E.\u003C\/em\u003EResearchers experimenting with live zebrafish witnessed a 200% increase in the strength of intestinal contractions soon after the organisms were exposed to the cholera-causing bacterium \u003Cem\u003EVibrio cholerae\u003C\/em\u003E. The strong contractions led to expulsion of native gut bacteria\u003Cem\u003E.\u003C\/em\u003E\u003C\/p\u003E\r\n","format":"limited_html"}],"field_summary_sentence":[{"value":"Cholera bacteria in gut of zebrafish induces strong intestinal contractions that eventually expel the gut contents."}],"uid":"30678","created_gmt":"2018-04-03 15:08:47","changed_gmt":"2018-04-18 15:46:54","author":"A. Maureen Rouhi","boilerplate_text":"","field_publication":"","field_article_url":"","dateline":{"date":"2018-04-03T00:00:00-04:00","iso_date":"2018-04-03T00:00:00-04:00","tz":"America\/New_York"},"extras":[],"hg_media":{"604636":{"id":"604636","type":"image","title":"Brian Hammer","body":null,"created":"1522767251","gmt_created":"2018-04-03 14:54:11","changed":"1522767251","gmt_changed":"2018-04-03 14:54:11","alt":"","file":{"fid":"230515","name":"Brian Hammer.tall250.jpg","image_path":"\/sites\/default\/files\/images\/Brian%20Hammer.tall250.jpg","image_full_path":"http:\/\/hg.gatech.edu\/\/sites\/default\/files\/images\/Brian%20Hammer.tall250.jpg","mime":"image\/jpeg","size":71622,"path_740":"http:\/\/hg.gatech.edu\/sites\/default\/files\/styles\/740xx_scale\/public\/images\/Brian%20Hammer.tall250.jpg?itok=J8jKqNeq"}},"604638":{"id":"604638","type":"image","title":"Cholera bacteria in gut of zebrafish (Courtesy of Raghuveer Parthasarathy)","body":null,"created":"1522767447","gmt_created":"2018-04-03 14:57:27","changed":"1522767447","gmt_changed":"2018-04-03 14:57:27","alt":"","file":{"fid":"230516","name":"2018 Cholera in Zebrafish.png","image_path":"\/sites\/default\/files\/images\/2018%20Cholera%20in%20Zebrafish.png","image_full_path":"http:\/\/hg.gatech.edu\/\/sites\/default\/files\/images\/2018%20Cholera%20in%20Zebrafish.png","mime":"image\/png","size":383925,"path_740":"http:\/\/hg.gatech.edu\/sites\/default\/files\/styles\/740xx_scale\/public\/images\/2018%20Cholera%20in%20Zebrafish.png?itok=vjOdLzc1"}}},"media_ids":["604636","604638"],"related_links":[{"url":"https:\/\/www.cos.gatech.edu\/news\/biosci\/physics\/cholera-bacterial-warfare","title":"Cholera Bacteria Stab and Poison Enemies so Predictably "},{"url":"https:\/\/www.cos.gatech.edu\/hg\/item\/589632","title":"A \u0022Gut Reaction\u0022 to Georgia Tech Biology Research"}],"groups":[{"id":"1278","name":"College of Sciences"},{"id":"1275","name":"School of Biological Sciences"}],"categories":[{"id":"146","name":"Life Sciences and Biology"}],"keywords":[{"id":"171897","name":"Vibrio cholerae"},{"id":"12952","name":"Brian Hammer"},{"id":"166882","name":"School of Biological Sciences"},{"id":"4896","name":"College of Sciences"}],"core_research_areas":[{"id":"39441","name":"Bioengineering and Bioscience"}],"news_room_topics":[{"id":"71881","name":"Science and Technology"}],"event_categories":[],"invited_audience":[],"affiliations":[],"classification":[],"areas_of_expertise":[],"news_and_recent_appearances":[],"phone":[],"contact":[{"value":"\u003Cp\u003EA. Maureen Rouhi, Ph.D.\u003Cbr \/\u003E\r\nDirector of Communications\u003Cbr \/\u003E\r\nCollege of Sciences\u003C\/p\u003E\r\n","format":"limited_html"}],"email":["maureen.rouhi@cos.gatech.edu"],"slides":[],"orientation":[],"userdata":""}}}