title: Organization of ribosomes and nucleoids in Escherichia coli cells during growth and in quiescence.
abstract: We have examined the distribution of ribosomes and nucleoids in live Escherichia coli cells under conditions of growth, division, and in quiescence. In exponentially growing cells translating ribosomes are interspersed among and around the nucleoid lobes, appearing as alternative bands under a fluorescence microscope. In contrast, inactive ribosomes either in stationary phase or after treatment with translation inhibitors such as chloramphenicol, tetracycline, and streptomycin gather predominantly at the cell poles and boundaries with concomitant compaction of the nucleoid. However, under all conditions, spatial segregation of the ribosomes and the nucleoids is well maintained. In dividing cells, ribosomes accumulate on both sides of the FtsZ ring at the mid cell. However, the distribution of the ribosomes among the new daughter cells is often unequal. Both the shape of the nucleoid and the pattern of ribosome distribution are also modified when the cells are exposed to rifampicin (transcription inhibitor), nalidixic acid (gyrase inhibitor), or A22 (MreB-cytoskeleton disruptor). Thus we conclude that the intracellular organization of the ribosomes and the nucleoids in bacteria are dynamic and critically dependent on cellular growth processes (replication, transcription, and translation) as well as on the integrity of the MreB cytoskeleton.
authors.affiliation: Department of Cell and Molecular Biology, Uppsala University, Box-596, BMC, 75124, Uppsala, Sweden.
authors.forename: Qian
authors.initials: Q
authors.lastname: Chai
authors.affiliation: Department of Cell and Molecular Biology, Uppsala University, Box-596, BMC, 75124, Uppsala, Sweden.
authors.forename: Bhupender
authors.initials: B
authors.lastname: Singh
authors.affiliation: Department of Cell and Molecular Biology, Uppsala University, Box-596, BMC, 75124, Uppsala, Sweden.
authors.forename: Kristin
authors.initials: K
authors.lastname: Peisker
authors.affiliation: Department of Cell and Molecular Biology, Uppsala University, Box-596, BMC, 75124, Uppsala, Sweden.
authors.forename: Nicole
authors.initials: N
authors.lastname: Metzendorf
authors.affiliation: Department of Cell and Molecular Biology, Uppsala University, Box-596, BMC, 75124, Uppsala, Sweden.
authors.forename: Xueliang
authors.initials: X
authors.lastname: Ge
authors.affiliation: Department of Cell and Molecular Biology, Uppsala University, Box-596, BMC, 75124, Uppsala, Sweden.
authors.forename: Santanu
authors.initials: S
authors.lastname: Dasgupta
authors.affiliation: Department of Cell and Molecular Biology, Uppsala University, Box-596, BMC, 75124, Uppsala, Sweden. Electronic address: suparna.sanyal@icm.uu.se.
authors.forename: Suparna
authors.initials: S
authors.lastname: Sanyal
mesh_terms: D048168:Escherichia coli K12 / Q000254:growth & development*; D029968:Escherichia coli Proteins / Q000096:biosynthesis*; D009268:Nalidixic Acid / Q000494:pharmacology; D019384:Nucleic Acid Synthesis Inhibitors / Q000494:pharmacology; D014176:Protein Biosynthesis / Q000235:genetics / Q000502:physiology*; D011500:Protein Synthesis Inhibitors / Q000494:pharmacology; D012270:Ribosomes / Q000378:metabolism*; D012293:Rifampin / Q000494:pharmacology; D059005:Topoisomerase II Inhibitors / Q000494:pharmacology
chemical_list: D029968:Escherichia coli Proteins; D019384:Nucleic Acid Synthesis Inhibitors; D011500:Protein Synthesis Inhibitors; D059005:Topoisomerase II Inhibitors; D009268:Nalidixic Acid; D012293:Rifampin
keywords: Antibiotics; Cell Division; Cytoskeleton; DNA Replication; FtsZ Ring; Nucleoid; Ribosomes; Subcellular Organelles; Transcription; Translation