John Mekalanos
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John Mekalanos
John Mekalanos is a microbiologist who is primarily known for leading one of the first teams that reported the discovery of the type VI secretion system as well as his work on the pathogenicity of the bacterial species ''Vibrio cholerae'', its toxin, and its secretion systems. Since 1998, he has been a member of the National Academy of Sciences. Education He started his research studies as a graduate student in the labs of R. John Collier and William Robert Romig at UCLA where his research was focused on studying the genetic and biochemical analysis of the cholera toxin secreted by the bacterium ''Vibrio cholerae''. Highlights of his career during this time was, along with Romig, the development of a screening assay designed to isolate the tox mutants of ''Vibrio cholerae'' (strains with altered toxin production ability) which led to the genetic mapping of the toxin-regulatory mutants in this bacterial species. He continued his work on cholera toxin as a post-doc at the Department ...
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Type VI Secretion System
The type VI secretion system (T6SS) is molecular machine used by a wide range of Gram-negative bacterial species to transport effectors from the interior (cytoplasm or cytosol) of a bacterial cell across the cellular envelope into an adjacent target cell. While often reported that the T6SS was discovered in 2006 by researchers studying the causative agent of cholera, ''Vibrio cholerae'', the first study demonstrating that T6SS genes encode a protein export apparatus was actually published in 2004, in a study of protein secretion by the fish pathogen ''Edwardsiella tarda''. Since then, it is estimated that at least a quarter of all pathogenic and non-pathogenic proteobacterial genomes encode for a T6SS, including pathogens of animals, plants, and humans, as well as soil, environmental or marine bacteria. Genes encoding for the T6SSs are commonly found chromosomally, but can also be harboured in mobile genetic elements and on plasmids mediating their transfer and increase in genetic ...
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Vibrio Cholerae
''Vibrio cholerae'' is a species of Gram-negative, facultative anaerobe and comma-shaped bacteria. The bacteria naturally live in brackish or saltwater where they attach themselves easily to the chitin-containing shells of crabs, shrimps, and other shellfish. Some strains of ''V. cholerae'' are pathogenic to humans and cause a deadly disease cholera, which can be derived from the consumption of undercooked or raw marine life species. ''V. cholerae'' was first described by Félix-Archimède Pouchet in 1849 as some kind of protozoa. Filippo Pacini correctly identified it as a bacterium and from him, the scientific name is adopted. The bacterium as the cause of cholera was discovered by Robert Koch in 1884. Sambhu Nath De isolated the cholera toxin and demonstrated the toxin as the cause of cholera in 1959. The bacterium has a flagellum at one pole and several pili throughout its cell surface. It undergoes respiratory and fermentative metabolism. Two serogroups called O1 and O139 ...
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Cholera Toxin
Cholera toxin (also known as choleragen and sometimes abbreviated to CTX, Ctx or CT) is AB5 multimeric protein complex secreted by the bacterium ''Vibrio cholerae''. CTX is responsible for the massive, watery diarrhea characteristic of cholera infection. It is a member of the Heat-labile enterotoxin family. History Cholera toxin was discovered in 1959 by Indian microbiologist Sambhu Nath De. Structure The complete toxin is a hexamer made up of a single copy of the A subunit (part A, enzymatic, ), and five copies of the B subunit (part B, receptor binding, ), denoted as AB5. Subunit B binds while subunit A activates the G protein which activates adenylate cyclase. The three-dimensional structure of the toxin was determined using X-ray crystallography by Zhang ''et al.'' in 1995. The five B subunits—each weighing 11 kDa, form a five-membered ring. The A subunit which is 28 kDa, has two important segments. The A1 portion of the chain (CTA1) is a globular enzyme payload t ...
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National Academy Of Sciences
The National Academy of Sciences (NAS) is a United States nonprofit, non-governmental organization. NAS is part of the National Academies of Sciences, Engineering, and Medicine, along with the National Academy of Engineering (NAE) and the National Academy of Medicine (NAM). As a national academy, new members of the organization are elected annually by current members, based on their distinguished and continuing achievements in original research. Election to the National Academy is one of the highest honors in the scientific field. Members of the National Academy of Sciences serve '' pro bono'' as "advisers to the nation" on science, engineering, and medicine. The group holds a congressional charter under Title 36 of the United States Code. Founded in 1863 as a result of an Act of Congress that was approved by Abraham Lincoln, the NAS is charged with "providing independent, objective advice to the nation on matters related to science and technology. ... to provide scien ...
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UCLA
The University of California, Los Angeles (UCLA) is a public land-grant research university in Los Angeles, California. UCLA's academic roots were established in 1881 as a teachers college then known as the southern branch of the California State Normal School (now San José State University). This school was absorbed with the official founding of UCLA as the Southern Branch of the University of California in 1919, making it the second-oldest of the 10-campus University of California system (after UC Berkeley). UCLA offers 337 undergraduate and graduate degree programs in a wide range of disciplines, enrolling about 31,600 undergraduate and 14,300 graduate and professional students. UCLA received 174,914 undergraduate applications for Fall 2022, including transfers, making the school the most applied-to university in the United States. The university is organized into the College of Letters and Science and 12 professional schools. Six of the schools offer undergraduate degre ...
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Harvard Medical School
Harvard Medical School (HMS) is the graduate medical school of Harvard University and is located in the Longwood Medical Area of Boston, Massachusetts. Founded in 1782, HMS is one of the oldest medical schools in the United States and is consistently ranked first for research among medical schools by '' U.S. News & World Report''. Unlike most other leading medical schools, HMS does not operate in conjunction with a single hospital but is directly affiliated with several teaching hospitals in the Boston area. Affiliated teaching hospitals and research institutes include Dana–Farber Cancer Institute, Massachusetts General Hospital, Brigham and Women's Hospital, Beth Israel Deaconess Medical Center, Boston Children's Hospital, McLean Hospital, Cambridge Health Alliance, The Baker Center for Children and Families, and Spaulding Rehabilitation Hospital. History Harvard Medical School was founded on September 19, 1782, after President Joseph Willard presented a report with ...
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Staphylococcus Aureus
''Staphylococcus aureus'' is a Gram-positive spherically shaped bacterium, a member of the Bacillota, and is a usual member of the microbiota of the body, frequently found in the upper respiratory tract and on the skin. It is often positive for catalase and nitrate reduction and is a facultative anaerobe that can grow without the need for oxygen. Although ''S. aureus'' usually acts as a commensal of the human microbiota, it can also become an opportunistic pathogen, being a common cause of skin infections including abscesses, respiratory infections such as sinusitis, and food poisoning. Pathogenic strains often promote infections by producing virulence factors such as potent protein toxins, and the expression of a cell-surface protein that binds and inactivates antibodies. ''S. aureus'' is one of the leading pathogens for deaths associated with antimicrobial resistance and the emergence of antibiotic-resistant strains, such as methicillin-resistant ''S. aureus'' (MRSA ...
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Contact-dependent Growth Inhibition
Contact-dependent growth inhibition (CDI) is a phenomenon where a bacterial cell may deliver a polymorphic toxin molecule into neighbouring bacterial cells upon direct cell-cell contact, causing growth arrest or cell death. Discovery CDI is now a blanket term to describe interbacterial competition that relies on direct cell-cell contact in bacteria. However, the phenomenon was first discovered in 2005 in the isolate EC93 of ''Escherichia coli'' found in rat intestine, and, in this case, was mediated by a Type V secretion system. This isolate dominated the rat's gut flora and appeared to be particularly good at outcompeting lab strains of ''E. coli'' when grown in co-culture''.'' The novel part of this discovery was the fact that the inhibitory effects of the isolated ''E. coli'' appeared to require direct cell-cell contact. Before CDI was discovered in this isolate, the only systems known to mediate direct interbacterial competition by intoxication were toxins secreted into the ...
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Eli Lilly And Company-Elanco Research Award
The Eli Lilly and Company-Elanco Research Award was a scientific award presented annually by the American Society for Microbiology (ASM) and sponsored by the Eli Lilly and Company and its subsidiary Elanco (which became an independent company in 2019). The prize was first awarded in 1936. Recipients were given 5000 US dollars (as of 2011). It honored young scientists under the age of 45. The award's purpose was not to compare the research of the younger scientists to the research of older scientists, but to encourage originality and independent thinking. The award was discontinued after the last award in 2018. Information about the award can no longer be found on the ASM website. Recipients The following people received the Eli Lilly and Company-Elanco Research Award:{{web archive , url=https://web.archive.org/web/20160611040032/http://www.asm.org/index.php/awards/research/140-awards-a-grants/past-laureates/7791-eli-lilly-and-company-elanco-research-award-past-laureates/ , title=El ...
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Newcomb Cleveland Prize
The Newcomb Cleveland Prize of the American Association for the Advancement of Science (AAAS) is annually awarded to author(s) of outstanding scientific paper published in the Research Articles or Reports sections of ''Science''. Established in 1923, funded by Newcomb Cleveland who remained anonymous until his death in 1951, and for this period it was known as the AAAS Thousand Dollar Prize. "The prize was inspired by Mr. Cleveland's belief that it was the scientist who counted and who needed the encouragement an unexpected monetary award could give." The present rules were instituted in 1975, previously it had gone to the author(s) of noteworthy papers, representing an outstanding contribution to science, presented in a regular session, sectional or societal, during the AAAS Annual Meeting. It is now sponsored by the Fodor Family Trust and includes a prize of $25,000. Recipients List of winners Current rules Previous rules See also * AAAS Award for Science Diplomacy * AAA ...
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American Academy Of Microbiology
The American Society for Microbiology (ASM), originally the Society of American Bacteriologists, is a professional organization for scientists who study viruses, bacteria, fungi, algae, and protozoa as well as other aspects of microbiology. It was founded in 1899. The Society publishes a variety of scientific journals, textbooks, and other educational materials related to microbiology and infectious diseases. ASM organizes annual meetings, as well as workshops and professional development opportunities for its members. History ASM was founded in 1899 under the name the "Society of American Bacteriologists." In December 1960, it was renamed the "American Society for Microbiology." Mission ASM's mission is "to promote and advance the microbial sciences." The society seeks to accomplish this mission through: * Publishing highly-cited publications * Running multi-disciplinary meetings * Deploying resources and expertise around the world * Advocating for scientific research * Fosteri ...
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