Loading…
Rhizobial homologs of the fatty acid transporter FadL facilitate perception of long-chain acyl-homoserine lactone signals
Quorum sensing (QS) using N-acyl homoserine lactones (AHLs) as signal molecules is a common strategy used by diverse Gram-negative bacteria. A widespread mechanism of AHL sensing involves binding of these molecules by cytosolic LuxR-type transcriptional regulators, which requires uptake of external...
Saved in:
Published in: | Proceedings of the National Academy of Sciences - PNAS 2014-07, Vol.111 (29), p.10702-10707 |
---|---|
Main Authors: | , |
Format: | Article |
Language: | English |
Subjects: | |
Citations: | Items that this one cites Items that cite this one |
Online Access: | Get full text |
Tags: |
Add Tag
No Tags, Be the first to tag this record!
|
cited_by | cdi_FETCH-LOGICAL-c591t-e2254c93ab4f7e1ef2bd6cd80574a4bcc24c97b5042a28a31a95d8ee5a1659003 |
---|---|
cites | cdi_FETCH-LOGICAL-c591t-e2254c93ab4f7e1ef2bd6cd80574a4bcc24c97b5042a28a31a95d8ee5a1659003 |
container_end_page | 10707 |
container_issue | 29 |
container_start_page | 10702 |
container_title | Proceedings of the National Academy of Sciences - PNAS |
container_volume | 111 |
creator | Krol, Elizaveta Becker, Anke |
description | Quorum sensing (QS) using N-acyl homoserine lactones (AHLs) as signal molecules is a common strategy used by diverse Gram-negative bacteria. A widespread mechanism of AHL sensing involves binding of these molecules by cytosolic LuxR-type transcriptional regulators, which requires uptake of external AHLs. The outer membrane is supposed to be an efficient barrier for diffusion of long-chain AHLs. Here we report evidence that in Sinorhizobium meliloti , sensing of AHLs with acyl chains composed of 14 or more carbons is facilitated by the outer membrane protein FadL Sₘ, a homolog of the Escherichia coli FadL Ec long-chain fatty acid transporter. The effect of fadL Sₘ on AHL sensing was more prominent for longer and more hydrophobic signal molecules. Using reporter gene fusions to QS target genes, we found that fadL Sₘ increased AHL sensitivity and accelerated the course of QS. In contrast to FadL Ec, FadL Sₘ did not support uptake of oleic acid, but did contribute to growth on palmitoleic acid. FadL Sₘ homologs from related symbiotic α-rhizobia and the plant pathogen Agrobacterium tumefaciens differed in their ability to facilitate long-chain AHL sensing or to support growth on oleic acid. FadL Aₜ was found to be ineffective toward long-chain AHLs. We obtained evidence that the predicted extracellular loop 5 of FadL Sₘ and further α-rhizobial FadL proteins contains determinants of specificity to long-chain AHLs. Replacement of a part of loop 5 by the corresponding region from α-rhizobial FadL proteins transferred sensitivity for long-chain AHLs to FadL Aₜ. |
doi_str_mv | 10.1073/pnas.1404929111 |
format | article |
fullrecord | <record><control><sourceid>jstor_proqu</sourceid><recordid>TN_cdi_jstor_primary_23803700</recordid><sourceformat>XML</sourceformat><sourcesystem>PC</sourcesystem><jstor_id>23803700</jstor_id><sourcerecordid>23803700</sourcerecordid><originalsourceid>FETCH-LOGICAL-c591t-e2254c93ab4f7e1ef2bd6cd80574a4bcc24c97b5042a28a31a95d8ee5a1659003</originalsourceid><addsrcrecordid>eNpdkUFv1DAUhCMEokvhzAmI1AuXtO85dhJfKqGqBaSVkICerRfH2fUqGwfbi7T8epzusgVO7zDfjDyeLHuNcIlQl1fTSOESOXDJJCI-yRYIEouKS3iaLQBYXTSc8bPsRQgbAJCigefZGRNJ4nW5yPZf1_aXay0N-dpt3eBWIXd9Htcm7ynGfU7adnn0NIbJ-Wh8fkfdMmnaDjZSNPlkvDZTtG6cjYMbV4Vekx2Tcz8Uc2gw3o4mH0hHl26wq5GG8DJ71qdjXh3veXZ_d_v95lOx_PLx882HZaGFxFgYxgTXsqSW97VB07O2q3TXgKg58VZrltS6FcAZsYZKJCm6xhhBWAkJUJ5n14fcadduTafNmNoMavJ2S36vHFn1rzLatVq5n4ojCoEiBbw_Bnj3Y2dCVFsbtBkGGo3bBYWiAmSiEjyhF_-hG7fzc9tEcSlFXT5QVwdKexeCN_3pMQhqnlXNs6rHWZPj7d8dTvyfHROQH4HZeYpDVEzOkcAS8uaAbEJ0_jGibKCsH_7p3UHvySlaeRvU_TcGWAEg54w15W_UVr3Y</addsrcrecordid><sourcetype>Open Access Repository</sourcetype><iscdi>true</iscdi><recordtype>article</recordtype><pqid>1549957354</pqid></control><display><type>article</type><title>Rhizobial homologs of the fatty acid transporter FadL facilitate perception of long-chain acyl-homoserine lactone signals</title><source>JSTOR Archival Journals and Primary Sources Collection</source><source>PubMed Central</source><creator>Krol, Elizaveta ; Becker, Anke</creator><creatorcontrib>Krol, Elizaveta ; Becker, Anke</creatorcontrib><description>Quorum sensing (QS) using N-acyl homoserine lactones (AHLs) as signal molecules is a common strategy used by diverse Gram-negative bacteria. A widespread mechanism of AHL sensing involves binding of these molecules by cytosolic LuxR-type transcriptional regulators, which requires uptake of external AHLs. The outer membrane is supposed to be an efficient barrier for diffusion of long-chain AHLs. Here we report evidence that in Sinorhizobium meliloti , sensing of AHLs with acyl chains composed of 14 or more carbons is facilitated by the outer membrane protein FadL Sₘ, a homolog of the Escherichia coli FadL Ec long-chain fatty acid transporter. The effect of fadL Sₘ on AHL sensing was more prominent for longer and more hydrophobic signal molecules. Using reporter gene fusions to QS target genes, we found that fadL Sₘ increased AHL sensitivity and accelerated the course of QS. In contrast to FadL Ec, FadL Sₘ did not support uptake of oleic acid, but did contribute to growth on palmitoleic acid. FadL Sₘ homologs from related symbiotic α-rhizobia and the plant pathogen Agrobacterium tumefaciens differed in their ability to facilitate long-chain AHL sensing or to support growth on oleic acid. FadL Aₜ was found to be ineffective toward long-chain AHLs. We obtained evidence that the predicted extracellular loop 5 of FadL Sₘ and further α-rhizobial FadL proteins contains determinants of specificity to long-chain AHLs. Replacement of a part of loop 5 by the corresponding region from α-rhizobial FadL proteins transferred sensitivity for long-chain AHLs to FadL Aₜ.</description><identifier>ISSN: 0027-8424</identifier><identifier>EISSN: 1091-6490</identifier><identifier>DOI: 10.1073/pnas.1404929111</identifier><identifier>PMID: 25002473</identifier><language>eng</language><publisher>United States: National Academy of Sciences</publisher><subject>Acyl-Butyrolactones - metabolism ; Agrobacterium tumefaciens ; Amino Acid Sequence ; Amino acids ; Bacterial proteins ; Bacterial Proteins - chemistry ; Bacterial Proteins - metabolism ; Binding sites ; Biological Sciences ; Biosynthesis ; Escherichia coli ; Fatty acids ; Fatty Acids - metabolism ; Fatty Acids, Monounsaturated - pharmacology ; Gene Expression Regulation, Bacterial - drug effects ; Genes ; Gram-negative bacteria ; Lactones ; Molecular Sequence Data ; Molecules ; Nonesterified fatty acids ; Oleic Acid - pharmacology ; Phenotype ; Phenotypes ; Protein Structure, Tertiary ; Quorum sensing ; Quorum Sensing - drug effects ; Quorum Sensing - genetics ; Sequence Homology, Amino Acid ; Signal Transduction - drug effects ; Sinorhizobium meliloti ; Sinorhizobium meliloti - drug effects ; Sinorhizobium meliloti - genetics ; Sinorhizobium meliloti - growth & development ; Sinorhizobium meliloti - metabolism</subject><ispartof>Proceedings of the National Academy of Sciences - PNAS, 2014-07, Vol.111 (29), p.10702-10707</ispartof><rights>copyright © 1993—2008 National Academy of Sciences of the United States of America</rights><rights>Copyright National Academy of Sciences Jul 22, 2014</rights><lds50>peer_reviewed</lds50><oa>free_for_read</oa><woscitedreferencessubscribed>false</woscitedreferencessubscribed><citedby>FETCH-LOGICAL-c591t-e2254c93ab4f7e1ef2bd6cd80574a4bcc24c97b5042a28a31a95d8ee5a1659003</citedby><cites>FETCH-LOGICAL-c591t-e2254c93ab4f7e1ef2bd6cd80574a4bcc24c97b5042a28a31a95d8ee5a1659003</cites></display><links><openurl>$$Topenurl_article</openurl><openurlfulltext>$$Topenurlfull_article</openurlfulltext><thumbnail>$$Uhttp://www.pnas.org/content/111/29.cover.gif</thumbnail><linktopdf>$$Uhttps://www.jstor.org/stable/pdf/23803700$$EPDF$$P50$$Gjstor$$H</linktopdf><linktohtml>$$Uhttps://www.jstor.org/stable/23803700$$EHTML$$P50$$Gjstor$$H</linktohtml><link.rule.ids>230,314,727,780,784,885,27924,27925,53791,53793,58238,58471</link.rule.ids><backlink>$$Uhttps://www.ncbi.nlm.nih.gov/pubmed/25002473$$D View this record in MEDLINE/PubMed$$Hfree_for_read</backlink></links><search><creatorcontrib>Krol, Elizaveta</creatorcontrib><creatorcontrib>Becker, Anke</creatorcontrib><title>Rhizobial homologs of the fatty acid transporter FadL facilitate perception of long-chain acyl-homoserine lactone signals</title><title>Proceedings of the National Academy of Sciences - PNAS</title><addtitle>Proc Natl Acad Sci U S A</addtitle><description>Quorum sensing (QS) using N-acyl homoserine lactones (AHLs) as signal molecules is a common strategy used by diverse Gram-negative bacteria. A widespread mechanism of AHL sensing involves binding of these molecules by cytosolic LuxR-type transcriptional regulators, which requires uptake of external AHLs. The outer membrane is supposed to be an efficient barrier for diffusion of long-chain AHLs. Here we report evidence that in Sinorhizobium meliloti , sensing of AHLs with acyl chains composed of 14 or more carbons is facilitated by the outer membrane protein FadL Sₘ, a homolog of the Escherichia coli FadL Ec long-chain fatty acid transporter. The effect of fadL Sₘ on AHL sensing was more prominent for longer and more hydrophobic signal molecules. Using reporter gene fusions to QS target genes, we found that fadL Sₘ increased AHL sensitivity and accelerated the course of QS. In contrast to FadL Ec, FadL Sₘ did not support uptake of oleic acid, but did contribute to growth on palmitoleic acid. FadL Sₘ homologs from related symbiotic α-rhizobia and the plant pathogen Agrobacterium tumefaciens differed in their ability to facilitate long-chain AHL sensing or to support growth on oleic acid. FadL Aₜ was found to be ineffective toward long-chain AHLs. We obtained evidence that the predicted extracellular loop 5 of FadL Sₘ and further α-rhizobial FadL proteins contains determinants of specificity to long-chain AHLs. Replacement of a part of loop 5 by the corresponding region from α-rhizobial FadL proteins transferred sensitivity for long-chain AHLs to FadL Aₜ.</description><subject>Acyl-Butyrolactones - metabolism</subject><subject>Agrobacterium tumefaciens</subject><subject>Amino Acid Sequence</subject><subject>Amino acids</subject><subject>Bacterial proteins</subject><subject>Bacterial Proteins - chemistry</subject><subject>Bacterial Proteins - metabolism</subject><subject>Binding sites</subject><subject>Biological Sciences</subject><subject>Biosynthesis</subject><subject>Escherichia coli</subject><subject>Fatty acids</subject><subject>Fatty Acids - metabolism</subject><subject>Fatty Acids, Monounsaturated - pharmacology</subject><subject>Gene Expression Regulation, Bacterial - drug effects</subject><subject>Genes</subject><subject>Gram-negative bacteria</subject><subject>Lactones</subject><subject>Molecular Sequence Data</subject><subject>Molecules</subject><subject>Nonesterified fatty acids</subject><subject>Oleic Acid - pharmacology</subject><subject>Phenotype</subject><subject>Phenotypes</subject><subject>Protein Structure, Tertiary</subject><subject>Quorum sensing</subject><subject>Quorum Sensing - drug effects</subject><subject>Quorum Sensing - genetics</subject><subject>Sequence Homology, Amino Acid</subject><subject>Signal Transduction - drug effects</subject><subject>Sinorhizobium meliloti</subject><subject>Sinorhizobium meliloti - drug effects</subject><subject>Sinorhizobium meliloti - genetics</subject><subject>Sinorhizobium meliloti - growth & development</subject><subject>Sinorhizobium meliloti - metabolism</subject><issn>0027-8424</issn><issn>1091-6490</issn><fulltext>true</fulltext><rsrctype>article</rsrctype><creationdate>2014</creationdate><recordtype>article</recordtype><recordid>eNpdkUFv1DAUhCMEokvhzAmI1AuXtO85dhJfKqGqBaSVkICerRfH2fUqGwfbi7T8epzusgVO7zDfjDyeLHuNcIlQl1fTSOESOXDJJCI-yRYIEouKS3iaLQBYXTSc8bPsRQgbAJCigefZGRNJ4nW5yPZf1_aXay0N-dpt3eBWIXd9Htcm7ynGfU7adnn0NIbJ-Wh8fkfdMmnaDjZSNPlkvDZTtG6cjYMbV4Vekx2Tcz8Uc2gw3o4mH0hHl26wq5GG8DJ71qdjXh3veXZ_d_v95lOx_PLx882HZaGFxFgYxgTXsqSW97VB07O2q3TXgKg58VZrltS6FcAZsYZKJCm6xhhBWAkJUJ5n14fcadduTafNmNoMavJ2S36vHFn1rzLatVq5n4ojCoEiBbw_Bnj3Y2dCVFsbtBkGGo3bBYWiAmSiEjyhF_-hG7fzc9tEcSlFXT5QVwdKexeCN_3pMQhqnlXNs6rHWZPj7d8dTvyfHROQH4HZeYpDVEzOkcAS8uaAbEJ0_jGibKCsH_7p3UHvySlaeRvU_TcGWAEg54w15W_UVr3Y</recordid><startdate>20140722</startdate><enddate>20140722</enddate><creator>Krol, Elizaveta</creator><creator>Becker, Anke</creator><general>National Academy of Sciences</general><general>National Acad Sciences</general><scope>FBQ</scope><scope>CGR</scope><scope>CUY</scope><scope>CVF</scope><scope>ECM</scope><scope>EIF</scope><scope>NPM</scope><scope>AAYXX</scope><scope>CITATION</scope><scope>7QG</scope><scope>7QL</scope><scope>7QP</scope><scope>7QR</scope><scope>7SN</scope><scope>7SS</scope><scope>7T5</scope><scope>7TK</scope><scope>7TM</scope><scope>7TO</scope><scope>7U9</scope><scope>8FD</scope><scope>C1K</scope><scope>FR3</scope><scope>H94</scope><scope>M7N</scope><scope>P64</scope><scope>RC3</scope><scope>5PM</scope></search><sort><creationdate>20140722</creationdate><title>Rhizobial homologs of the fatty acid transporter FadL facilitate perception of long-chain acyl-homoserine lactone signals</title><author>Krol, Elizaveta ; Becker, Anke</author></sort><facets><frbrtype>5</frbrtype><frbrgroupid>cdi_FETCH-LOGICAL-c591t-e2254c93ab4f7e1ef2bd6cd80574a4bcc24c97b5042a28a31a95d8ee5a1659003</frbrgroupid><rsrctype>articles</rsrctype><prefilter>articles</prefilter><language>eng</language><creationdate>2014</creationdate><topic>Acyl-Butyrolactones - metabolism</topic><topic>Agrobacterium tumefaciens</topic><topic>Amino Acid Sequence</topic><topic>Amino acids</topic><topic>Bacterial proteins</topic><topic>Bacterial Proteins - chemistry</topic><topic>Bacterial Proteins - metabolism</topic><topic>Binding sites</topic><topic>Biological Sciences</topic><topic>Biosynthesis</topic><topic>Escherichia coli</topic><topic>Fatty acids</topic><topic>Fatty Acids - metabolism</topic><topic>Fatty Acids, Monounsaturated - pharmacology</topic><topic>Gene Expression Regulation, Bacterial - drug effects</topic><topic>Genes</topic><topic>Gram-negative bacteria</topic><topic>Lactones</topic><topic>Molecular Sequence Data</topic><topic>Molecules</topic><topic>Nonesterified fatty acids</topic><topic>Oleic Acid - pharmacology</topic><topic>Phenotype</topic><topic>Phenotypes</topic><topic>Protein Structure, Tertiary</topic><topic>Quorum sensing</topic><topic>Quorum Sensing - drug effects</topic><topic>Quorum Sensing - genetics</topic><topic>Sequence Homology, Amino Acid</topic><topic>Signal Transduction - drug effects</topic><topic>Sinorhizobium meliloti</topic><topic>Sinorhizobium meliloti - drug effects</topic><topic>Sinorhizobium meliloti - genetics</topic><topic>Sinorhizobium meliloti - growth & development</topic><topic>Sinorhizobium meliloti - metabolism</topic><toplevel>peer_reviewed</toplevel><toplevel>online_resources</toplevel><creatorcontrib>Krol, Elizaveta</creatorcontrib><creatorcontrib>Becker, Anke</creatorcontrib><collection>AGRIS</collection><collection>Medline</collection><collection>MEDLINE</collection><collection>MEDLINE (Ovid)</collection><collection>MEDLINE</collection><collection>MEDLINE</collection><collection>PubMed</collection><collection>CrossRef</collection><collection>Animal Behavior Abstracts</collection><collection>Bacteriology Abstracts (Microbiology B)</collection><collection>Calcium & Calcified Tissue Abstracts</collection><collection>Chemoreception Abstracts</collection><collection>Ecology Abstracts</collection><collection>Entomology Abstracts (Full archive)</collection><collection>Immunology Abstracts</collection><collection>Neurosciences Abstracts</collection><collection>Nucleic Acids Abstracts</collection><collection>Oncogenes and Growth Factors Abstracts</collection><collection>Virology and AIDS Abstracts</collection><collection>Technology Research Database</collection><collection>Environmental Sciences and Pollution Management</collection><collection>Engineering Research Database</collection><collection>AIDS and Cancer Research Abstracts</collection><collection>Algology Mycology and Protozoology Abstracts (Microbiology C)</collection><collection>Biotechnology and BioEngineering Abstracts</collection><collection>Genetics Abstracts</collection><collection>PubMed Central (Full Participant titles)</collection><jtitle>Proceedings of the National Academy of Sciences - PNAS</jtitle></facets><delivery><delcategory>Remote Search Resource</delcategory><fulltext>fulltext</fulltext></delivery><addata><au>Krol, Elizaveta</au><au>Becker, Anke</au><format>journal</format><genre>article</genre><ristype>JOUR</ristype><atitle>Rhizobial homologs of the fatty acid transporter FadL facilitate perception of long-chain acyl-homoserine lactone signals</atitle><jtitle>Proceedings of the National Academy of Sciences - PNAS</jtitle><addtitle>Proc Natl Acad Sci U S A</addtitle><date>2014-07-22</date><risdate>2014</risdate><volume>111</volume><issue>29</issue><spage>10702</spage><epage>10707</epage><pages>10702-10707</pages><issn>0027-8424</issn><eissn>1091-6490</eissn><abstract>Quorum sensing (QS) using N-acyl homoserine lactones (AHLs) as signal molecules is a common strategy used by diverse Gram-negative bacteria. A widespread mechanism of AHL sensing involves binding of these molecules by cytosolic LuxR-type transcriptional regulators, which requires uptake of external AHLs. The outer membrane is supposed to be an efficient barrier for diffusion of long-chain AHLs. Here we report evidence that in Sinorhizobium meliloti , sensing of AHLs with acyl chains composed of 14 or more carbons is facilitated by the outer membrane protein FadL Sₘ, a homolog of the Escherichia coli FadL Ec long-chain fatty acid transporter. The effect of fadL Sₘ on AHL sensing was more prominent for longer and more hydrophobic signal molecules. Using reporter gene fusions to QS target genes, we found that fadL Sₘ increased AHL sensitivity and accelerated the course of QS. In contrast to FadL Ec, FadL Sₘ did not support uptake of oleic acid, but did contribute to growth on palmitoleic acid. FadL Sₘ homologs from related symbiotic α-rhizobia and the plant pathogen Agrobacterium tumefaciens differed in their ability to facilitate long-chain AHL sensing or to support growth on oleic acid. FadL Aₜ was found to be ineffective toward long-chain AHLs. We obtained evidence that the predicted extracellular loop 5 of FadL Sₘ and further α-rhizobial FadL proteins contains determinants of specificity to long-chain AHLs. Replacement of a part of loop 5 by the corresponding region from α-rhizobial FadL proteins transferred sensitivity for long-chain AHLs to FadL Aₜ.</abstract><cop>United States</cop><pub>National Academy of Sciences</pub><pmid>25002473</pmid><doi>10.1073/pnas.1404929111</doi><tpages>6</tpages><oa>free_for_read</oa></addata></record> |
fulltext | fulltext |
identifier | ISSN: 0027-8424 |
ispartof | Proceedings of the National Academy of Sciences - PNAS, 2014-07, Vol.111 (29), p.10702-10707 |
issn | 0027-8424 1091-6490 |
language | eng |
recordid | cdi_jstor_primary_23803700 |
source | JSTOR Archival Journals and Primary Sources Collection; PubMed Central |
subjects | Acyl-Butyrolactones - metabolism Agrobacterium tumefaciens Amino Acid Sequence Amino acids Bacterial proteins Bacterial Proteins - chemistry Bacterial Proteins - metabolism Binding sites Biological Sciences Biosynthesis Escherichia coli Fatty acids Fatty Acids - metabolism Fatty Acids, Monounsaturated - pharmacology Gene Expression Regulation, Bacterial - drug effects Genes Gram-negative bacteria Lactones Molecular Sequence Data Molecules Nonesterified fatty acids Oleic Acid - pharmacology Phenotype Phenotypes Protein Structure, Tertiary Quorum sensing Quorum Sensing - drug effects Quorum Sensing - genetics Sequence Homology, Amino Acid Signal Transduction - drug effects Sinorhizobium meliloti Sinorhizobium meliloti - drug effects Sinorhizobium meliloti - genetics Sinorhizobium meliloti - growth & development Sinorhizobium meliloti - metabolism |
title | Rhizobial homologs of the fatty acid transporter FadL facilitate perception of long-chain acyl-homoserine lactone signals |
url | http://sfxeu10.hosted.exlibrisgroup.com/loughborough?ctx_ver=Z39.88-2004&ctx_enc=info:ofi/enc:UTF-8&ctx_tim=2025-01-04T07%3A58%3A28IST&url_ver=Z39.88-2004&url_ctx_fmt=infofi/fmt:kev:mtx:ctx&rfr_id=info:sid/primo.exlibrisgroup.com:primo3-Article-jstor_proqu&rft_val_fmt=info:ofi/fmt:kev:mtx:journal&rft.genre=article&rft.atitle=Rhizobial%20homologs%20of%20the%20fatty%20acid%20transporter%20FadL%20facilitate%20perception%20of%20long-chain%20acyl-homoserine%20lactone%20signals&rft.jtitle=Proceedings%20of%20the%20National%20Academy%20of%20Sciences%20-%20PNAS&rft.au=Krol,%20Elizaveta&rft.date=2014-07-22&rft.volume=111&rft.issue=29&rft.spage=10702&rft.epage=10707&rft.pages=10702-10707&rft.issn=0027-8424&rft.eissn=1091-6490&rft_id=info:doi/10.1073/pnas.1404929111&rft_dat=%3Cjstor_proqu%3E23803700%3C/jstor_proqu%3E%3Cgrp_id%3Ecdi_FETCH-LOGICAL-c591t-e2254c93ab4f7e1ef2bd6cd80574a4bcc24c97b5042a28a31a95d8ee5a1659003%3C/grp_id%3E%3Coa%3E%3C/oa%3E%3Curl%3E%3C/url%3E&rft_id=info:oai/&rft_pqid=1549957354&rft_id=info:pmid/25002473&rft_jstor_id=23803700&rfr_iscdi=true |