{"doi":"10.1128/jb.00796-16","title":"Effector Overlap between the\n            <i>lac</i>\n            and\n            <i>mel</i>\n            Operons of Escherichia coli: Induction of the\n            <i>mel</i>\n            Operon with β-Galactosides","abstract":"<jats:title>ABSTRACT</jats:title>\n          <jats:p>\n            The\n            <jats:italic>lac</jats:italic>\n            (lactose) operon (which processes β-galactosides) and the\n            <jats:italic>mel</jats:italic>\n            (melibiose) operon (which processes α-galactosides) of\n            <jats:named-content content-type=\"genus-species\">Escherichia coli</jats:named-content>\n            have a close historical connection. A number of shared substrates and effectors of the permeases and regulatory proteins have been reported over the years. Until now, β-thiogalactosides like TMG (methyl-β-\n            <jats:sc>d</jats:sc>\n            -thiogalactopyranoside) and IPTG (isopropyl-β-\n            <jats:sc>d</jats:sc>\n            -thiogalactopyranoside) have not generally been considered to be inducers of the\n            <jats:italic>mel</jats:italic>\n            operon. The same is true for β-galactosides such as lactose [β-\n            <jats:sc>d</jats:sc>\n            -galactopyranosyl-(1→4)-\n            <jats:sc>d</jats:sc>\n            -glucose], which is a substrate but is not itself an inducer of the\n            <jats:italic>lac</jats:italic>\n            operon. This report shows that all three sugars can induce the\n            <jats:italic>mel</jats:italic>\n            operon significantly when they are accumulated in the cell by Lac permease. Strong induction by β-thiogalactosides is observed in the presence of Lac permease, and strong induction by lactose (more than 200-fold) is observed in the absence of β-galactosidase. This finding calls for reevaluation of TMG uptake experiments as assays for Lac permease that were performed with\n            <jats:italic>mel</jats:italic>\n            <jats:sup>\n              <jats:italic>+</jats:italic>\n            </jats:sup>\n            strains.\n          </jats:p>\n          <jats:p>\n            <jats:bold>IMPORTANCE</jats:bold>\n            The typical textbook picture of bacterial operons is that of stand-alone units of genetic information that perform, in a regulated manner, well-defined cellular functions. Less attention is given to the extensive interactions that can be found between operons. Well-described examples of such interactions are the effector molecules shared by the\n            <jats:italic>lac</jats:italic>\n            and\n            <jats:italic>mel</jats:italic>\n            operons. Here, we show that this set has to be extended to include β-galactosides, which have been, until now, considered not to effect the expression of the\n            <jats:italic>mel</jats:italic>\n            operon. That they can be inducers of the\n            <jats:italic>mel</jats:italic>\n            operon as well as the\n            <jats:italic>lac</jats:italic>\n            operon has not been noted in decades of research because of the\n            <jats:named-content content-type=\"genus-species\">Escherichia coli</jats:named-content>\n            genetic background used in previous studies.\n          </jats:p>","journal":"Journal of Bacteriology","year":2017,"id":14936,"datarank":0.33903324528968637,"base_score":1.6094379124341003,"endowment":1.6094379124341003,"self_citation_contribution":0.24141568686511508,"citation_network_contribution":0.09761755842457129,"self_endowment_contribution":0.24141568686511508,"citer_contribution":0.09761755842457129,"corpus_percentile":null,"corpus_rank":null,"citation_count":4,"citer_count":4,"citers_with_citation_signal":3,"citers_with_endowment":3,"datacite_reuse_total":0,"is_dataset":false,"is_dataset_confidence":null,"is_oa":false,"file_count":0,"downloads":0,"has_version_chain":false,"published_date":null,"fair_score":null,"fair_percentile":null,"algorithm_id":"datarank_citation_only_1hop_v6","ranking_scope":"data_only","authors":[{"id":115868,"name":"Stefan Oehler","orcid":null,"position":1,"is_corresponding":false},{"id":115867,"name":"Atul Narang","orcid":null,"position":0,"is_corresponding":false}],"reference_count":0,"raw_metadata":{"has_enrichment":true,"base_score":1.6094379124341003,"endowment":1.6094379124341003,"datacite_reuse_total":0,"file_count":0,"downloads":0,"views":0,"has_version_chain":false,"is_dataset":false,"is_oa":false,"pmid":"28193904","pmcid":"PMC5388812","openalex_id":"https://openalex.org/W2588569119","authors":[],"funders":[{"funder_name":"Department of Science and Technology (DST), India","grant_id":"SR/SO/BB-79/2010","title":null}],"total_grants":1,"fwci":0.2186,"citation_percentile":0.64422803,"influential_citations":0,"citation_trend":[{"year":2017,"count":1},{"year":2021,"count":1},{"year":2023,"count":1},{"year":2025,"count":1}],"oa_status":"bronze","license":"https://journals.asm.org/non-commercial-tdm-license","oa_locations":[{"url":"https://jb.asm.org/content/jb/199/9/e00796-16.full.pdf","host_type":"journal"},{"url":"https://doi.org/10.1128/jb.00796-16","host_type":"BRONZE"},{"url":"https://jb.asm.org/content/jb/199/9/e00796-16.full.pdf","host_type":"publisher"},{"url":"https://journals.asm.org/doi/pdf/10.1128/JB.00796-16","host_type":"publisher"},{"url":"https://pubmed.ncbi.nlm.nih.gov/28193904","host_type":"repository"},{"url":"https://www.ncbi.nlm.nih.gov/pmc/articles/5388812","host_type":"repository"}],"fields_of_study":["Bacterial Genetics and Biotechnology","Escherichia coli research studies","RNA and protein synthesis mechanisms","Medicine","Biology","Chemistry","Escherichia coli","Galactosides","Glucose","Lac Operon","Lactose","Melibiose","Membrane Transport Proteins","Operon","beta-Galactosidase"],"mesh_terms":["beta-Galactosidase","Escherichia coli","Galactosides","Glucose","Lac Operon","Lactose","Melibiose","Operon","Membrane Transport Proteins"],"keywords":["Operon","lac operon","Permease","Galactosides","Biology","Inducer","L-arabinose operon","Escherichia coli","Effector","Lac repressor","gal operon","Biochemistry","Genetics","Galactose","Gene","coactivator","Beta-galactosides","Mel Operon"],"sdg_mappings":[],"linked_datasets":[],"clinical_trials":[],"software_tools":[],"database_accessions":[],"source":"live","citation_network_status":"fetched"},"created_at":"2026-06-01T15:37:42.939987Z","pmid":null,"pmcid":null,"fwci":null,"citation_percentile":null,"influential_citations":0,"oa_status":null,"license":null,"views":0,"total_file_size_bytes":0,"version_count":0,"fair_f":null,"fair_a":null,"fair_i":null,"fair_r":null,"fair_zscore":null,"fair_rationale":null,"fair_model":null,"fair_agent_version":null,"fair_fulltext_source":null,"fair_has_llm":null,"fair_computed_at":null,"clinical_trials":[],"software_tools":[],"db_accessions":[],"linked_datasets":[],"topics":[]}