{"id":{"repo_id":"uiuc","oai_identifier":"oai:www.ideals.illinois.edu:2142/113970"},"canonical_url":"https://search.dev.ndltd.org/etd/uiuc/oai:www.ideals.illinois.edu:2142/113970","repository":{"repo_id":"uiuc","name":"University of Illinois - Urbana-Champaign","base_url":"https://www.ideals.illinois.edu/oai-pmh"},"display":{"title":"How Escherichia coli uses environmental cysteine","abstract":"Submission published under a 24 month embargo labeled 'U of I Access', the embargo will last until 2023-12-01","abstract_html":"Submission published under a 24 month embargo labeled 'U of I Access', the embargo will last until 2023-12-01","abstract_has_math":false,"creators":["Zhou, Yidan"],"institution":"University of Illinois at Urbana-Champaign","degree_name":"Ph.D.","degree_level":"Dissertation","degree_discipline":"Microbiology","degree_department":null,"school":null,"contributors":["Imlay, James","Kuzminov, Andrei","Vanderpool, Cari","Kehl-Fie, Thomas"],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2022,"date_issued":"2022-04-29T21:45:55Z","date_published":"2022-04-29T21:45:55Z","updated_at":"2026-07-22T22:24:53Z","subjects":["Microbiology"],"languages":["en","eng"],"rights":["Copyright 2021 Yidan Zhou"],"rights_urls":[],"identifier_entries":[]},"links":{"outbound_url":"http://hdl.handle.net/2142/113970","outbound_label":"Handle","outbound_source":"dc:identifier"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor","label":"Contributor","values":["Imlay, James","Kuzminov, Andrei","Vanderpool, Cari","Kehl-Fie, Thomas"]},{"key":"dc:creator","label":"Author","values":["Zhou, Yidan"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date","label":"Dc Date","values":["2022-04-29T21:45:55Z","2024-04-29T21:47:53Z","2021-12","2021-12-01"]},{"key":"dc:type","label":"Dc Type","values":["text","Thesis"]},{"key":"thesis:degree_discipline","label":"Discipline","values":["Microbiology"]},{"key":"thesis:degree_level","label":"Degree Level","values":["Dissertation"]},{"key":"thesis:degree_name","label":"Degree Name","values":["Ph.D."]},{"key":"thesis:institution_name","label":"Thesis Institution Name","values":["University of Illinois at Urbana-Champaign"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["Microbiology"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:language","label":"Dc Language","values":["en","eng"]},{"key":"dc:rights","label":"Dc Rights","values":["Copyright 2021 Yidan Zhou"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier","label":"Identifier","values":["http://hdl.handle.net/2142/113970"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description","label":"Description","values":["Submission published under a 24 month embargo labeled 'U of I Access', the embargo will last until 2023-12-01","The student, Yidan Zhou, accepted the attached license on 2021-11-20 at 09:42.","The student, Yidan Zhou, submitted this Dissertation for approval on 2021-11-20 at 09:48.","This Dissertation was approved for publication on 2021-12-01 at 08:03.","DSpace SAF Submission Ingestion Package generated from Vireo submission #17233 on 2022-04-06 at 17:16:54","Made available in DSpace on 2022-04-29T21:45:55Z (GMT). No. of bitstreams: 2 ZHOU-DISSERTATION-2021.pdf: 9324248 bytes, checksum: 5c97a68456c9f3cdb905cabcaacbfadc (MD5) LICENSE.txt: 4207 bytes, checksum: 8f430f301373b4717a2a76b677759255 (MD5) Previous issue date: 2021-12-01","Embargo set by: Seth Robbins for item 123334 Lift date: 2024-04-29T21:46:25Z Reason: Author requested U of Illinois access only (OA after 2yrs) in Vireo ETD system","Embargo set by: Seth Robbins for item 123334 Lift date: 2024-04-29T21:47:53Z Reason: Author requested U of Illinois access only (OA after 2yrs) in Vireo ETD system","Author requested U of Illinois access only (OA after 2yrs) in Vireo ETD system","U of I Only","Sulfur is an essential element for all forms of life. Bacteria have dedicated importers for a range of sulfur containing molecules (cystine, sulfate, taurine, glutathione). These importers are induced when bacteria are sulfur limited. Once imported, these sulfur compounds are first converted into usable cysteine and then are incorporated into biomolecules; thus, one would expect that cysteine import would be the most economical route for cells to acquire sulfur. However, uniquely among the amino acid transporters, cysteine importers are poorly characterized in the microbial world. We have demonstrated that wild-type E. coli cannot assimilate cysteine as sulfur source in the presence of other amino acids. Four transporters have adventitious cysteine import activity, but they do not import cysteine when their natural substrates are around. If these four transporters are deleted, E. coli can no longer scavenge trace cysteine. The surprising lack of an effective route to assimilate sulfur from cysteine may be due to the problems that rapid cysteine import can cause. Does this mean that cysteine is of no use for E. coli? The story doesn’t end like this. E. coli possesses a cysteine-specific importer, called YhaO, that is induced only when external cysteine is abundant. Downstream of yhaO sits yhaM, encoding a cysteine desulfidase that degrades cysteine to pyruvate, ammonia, and hydrogen sulfide. We found that this process is fast enough to allow cells to use cysteine as sole carbon or nitrogen source. YhaM is the primary sulfide producer when cells are exposed to abundant cysteine. Expression data showed that yhaO was most strongly induced when E. coli grows on poor carbon sources. The strong induction did not occur when Crp was deleted, indicating that Crp may regulate YhaOM. Indeed, Crp null mutants could not grow on cysteine as sole carbon source. We conclude that extracellular cysteine is utilized as a carbon or nitrogen source rather than as a cysteine source for protein biosynthesis."]},{"key":"dc:format","label":"Dc Format","values":["application/pdf"]},{"key":"dc:title","label":"Title","values":["How Escherichia coli uses environmental cysteine"]}]}],"canonical_facts":{"dc:contributor":["Imlay, James","Kuzminov, Andrei","Vanderpool, Cari","Kehl-Fie, Thomas"],"dc:creator":["Zhou, Yidan"],"dc:date":["2022-04-29T21:45:55Z","2024-04-29T21:47:53Z","2021-12","2021-12-01"],"dc:description":["Submission published under a 24 month embargo labeled 'U of I Access', the embargo will last until 2023-12-01","The student, Yidan Zhou, accepted the attached license on 2021-11-20 at 09:42.","The student, Yidan Zhou, submitted this Dissertation for approval on 2021-11-20 at 09:48.","This Dissertation was approved for publication on 2021-12-01 at 08:03.","DSpace SAF Submission Ingestion Package generated from Vireo submission #17233 on 2022-04-06 at 17:16:54","Made available in DSpace on 2022-04-29T21:45:55Z (GMT). No. of bitstreams: 2 ZHOU-DISSERTATION-2021.pdf: 9324248 bytes, checksum: 5c97a68456c9f3cdb905cabcaacbfadc (MD5) LICENSE.txt: 4207 bytes, checksum: 8f430f301373b4717a2a76b677759255 (MD5) Previous issue date: 2021-12-01","Embargo set by: Seth Robbins for item 123334 Lift date: 2024-04-29T21:46:25Z Reason: Author requested U of Illinois access only (OA after 2yrs) in Vireo ETD system","Embargo set by: Seth Robbins for item 123334 Lift date: 2024-04-29T21:47:53Z Reason: Author requested U of Illinois access only (OA after 2yrs) in Vireo ETD system","Author requested U of Illinois access only (OA after 2yrs) in Vireo ETD system","U of I Only","Sulfur is an essential element for all forms of life. Bacteria have dedicated importers for a range of sulfur containing molecules (cystine, sulfate, taurine, glutathione). These importers are induced when bacteria are sulfur limited. Once imported, these sulfur compounds are first converted into usable cysteine and then are incorporated into biomolecules; thus, one would expect that cysteine import would be the most economical route for cells to acquire sulfur. However, uniquely among the amino acid transporters, cysteine importers are poorly characterized in the microbial world. We have demonstrated that wild-type E. coli cannot assimilate cysteine as sulfur source in the presence of other amino acids. Four transporters have adventitious cysteine import activity, but they do not import cysteine when their natural substrates are around. If these four transporters are deleted, E. coli can no longer scavenge trace cysteine. The surprising lack of an effective route to assimilate sulfur from cysteine may be due to the problems that rapid cysteine import can cause. Does this mean that cysteine is of no use for E. coli? The story doesn’t end like this. E. coli possesses a cysteine-specific importer, called YhaO, that is induced only when external cysteine is abundant. Downstream of yhaO sits yhaM, encoding a cysteine desulfidase that degrades cysteine to pyruvate, ammonia, and hydrogen sulfide. We found that this process is fast enough to allow cells to use cysteine as sole carbon or nitrogen source. YhaM is the primary sulfide producer when cells are exposed to abundant cysteine. Expression data showed that yhaO was most strongly induced when E. coli grows on poor carbon sources. The strong induction did not occur when Crp was deleted, indicating that Crp may regulate YhaOM. Indeed, Crp null mutants could not grow on cysteine as sole carbon source. We conclude that extracellular cysteine is utilized as a carbon or nitrogen source rather than as a cysteine source for protein biosynthesis."],"dc:format":["application/pdf"],"dc:identifier":["http://hdl.handle.net/2142/113970"],"dc:language":["en","eng"],"dc:rights":["Copyright 2021 Yidan Zhou"],"dc:subject":["Microbiology"],"dc:title":["How Escherichia coli uses environmental cysteine"],"dc:type":["text","Thesis"],"thesis:degree_discipline":["Microbiology"],"thesis:degree_level":["Dissertation"],"thesis:degree_name":["Ph.D."],"thesis:institution_name":["University of Illinois at Urbana-Champaign"]},"updated_at":"2026-07-22T22:24:53Z"}