Role of multiple ftsz rings in chloroplast division under oligotrophic and eutrophic conditions in the unicellular green alga nannochloris bacillaris (chlorophyta, trebouxiophyceae)

Nobuko Sumiya, Satomi Owari, Koichi Watanabe, Shigeyuki Kawano

Research output: Contribution to journalArticle

Abstract

Chloroplasts of the unicellular green alga Nannochloris bacillaris Naumann cultured under nutrient-enriched conditions have multiple rings of FtsZ, a prokaryote-derived chloroplast division protein. We previously reported that synthesis of excess chloroplast DNA and formation of multiple FtsZ rings occur simultaneously. To clarify the role of multiple FtsZ rings in chloroplast division, we investigated chloroplast DNA synthesis and ring formation in cells cultured under various culture conditions. Cells transferred from a nutrient-enriched medium to an inorganic medium in the light showed a drop in cell division rate, a reduction in chloroplast DNA content, and changes in the shape of chloroplast nucleoids as cells divided. We then examined DNA synthesis by immunodetecting BrdU incorporated into DNA strands using the anti-BrdU antibody. BrdU-labeled nuclei were clearly observed in cells 48h after transfer into the inorganic medium, while only weak punctate signals were visible in the chloroplasts. In parallel, the number of FtsZ rings decreased from 6 to only 1. When the cells were transferred from an inorganic medium to a nutrient-enriched medium, the number of cells increased only slightly in the first 12h after transfer; after this time, however, they started to divide more quickly and increased exponentially. Chloroplast nucleoids changed from punctate to rod-like structures, and active chloroplast DNA synthesis and FtsZ ring formation were observed. On the basis of our results, we conclude that multiple FtsZ ring assembly and chloroplast DNA duplication under nutrient-rich conditions facilitate chloroplast division after transfer to oligotrophic conditions without further duplication of chloroplast DNA and formation of new FtsZ rings.

Original languageEnglish
Pages (from-to)1187-1196
Number of pages10
JournalJournal of Phycology
Volume48
Issue number5
DOIs
Publication statusPublished - 2012 Oct
Externally publishedYes

Fingerprint

Nannochloris
green alga
chloroplast
Chlorophyta
chloroplast DNA
chloroplasts
DNA
synthesis
nutrients
cells
nutrient
prokaryotic cells
Trebouxiophyceae
cultured cells
cell division
antibodies
prokaryote

Keywords

  • Chloroplast division
  • Chloroplast DNA synthesis
  • Chloroplast nucleoid
  • FtsZ ring
  • Nannochloris bacillaris

ASJC Scopus subject areas

  • Aquatic Science
  • Plant Science

Cite this

Role of multiple ftsz rings in chloroplast division under oligotrophic and eutrophic conditions in the unicellular green alga nannochloris bacillaris (chlorophyta, trebouxiophyceae). / Sumiya, Nobuko; Owari, Satomi; Watanabe, Koichi; Kawano, Shigeyuki.

In: Journal of Phycology, Vol. 48, No. 5, 10.2012, p. 1187-1196.

Research output: Contribution to journalArticle

@article{c47b6fad4c224b11b4199eb4779473ef,
title = "Role of multiple ftsz rings in chloroplast division under oligotrophic and eutrophic conditions in the unicellular green alga nannochloris bacillaris (chlorophyta, trebouxiophyceae)",
abstract = "Chloroplasts of the unicellular green alga Nannochloris bacillaris Naumann cultured under nutrient-enriched conditions have multiple rings of FtsZ, a prokaryote-derived chloroplast division protein. We previously reported that synthesis of excess chloroplast DNA and formation of multiple FtsZ rings occur simultaneously. To clarify the role of multiple FtsZ rings in chloroplast division, we investigated chloroplast DNA synthesis and ring formation in cells cultured under various culture conditions. Cells transferred from a nutrient-enriched medium to an inorganic medium in the light showed a drop in cell division rate, a reduction in chloroplast DNA content, and changes in the shape of chloroplast nucleoids as cells divided. We then examined DNA synthesis by immunodetecting BrdU incorporated into DNA strands using the anti-BrdU antibody. BrdU-labeled nuclei were clearly observed in cells 48h after transfer into the inorganic medium, while only weak punctate signals were visible in the chloroplasts. In parallel, the number of FtsZ rings decreased from 6 to only 1. When the cells were transferred from an inorganic medium to a nutrient-enriched medium, the number of cells increased only slightly in the first 12h after transfer; after this time, however, they started to divide more quickly and increased exponentially. Chloroplast nucleoids changed from punctate to rod-like structures, and active chloroplast DNA synthesis and FtsZ ring formation were observed. On the basis of our results, we conclude that multiple FtsZ ring assembly and chloroplast DNA duplication under nutrient-rich conditions facilitate chloroplast division after transfer to oligotrophic conditions without further duplication of chloroplast DNA and formation of new FtsZ rings.",
keywords = "Chloroplast division, Chloroplast DNA synthesis, Chloroplast nucleoid, FtsZ ring, Nannochloris bacillaris",
author = "Nobuko Sumiya and Satomi Owari and Koichi Watanabe and Shigeyuki Kawano",
year = "2012",
month = "10",
doi = "10.1111/j.1529-8817.2012.01204.x",
language = "English",
volume = "48",
pages = "1187--1196",
journal = "Journal of Phycology",
issn = "0022-3646",
publisher = "Wiley-Blackwell",
number = "5",

}

TY - JOUR

T1 - Role of multiple ftsz rings in chloroplast division under oligotrophic and eutrophic conditions in the unicellular green alga nannochloris bacillaris (chlorophyta, trebouxiophyceae)

AU - Sumiya, Nobuko

AU - Owari, Satomi

AU - Watanabe, Koichi

AU - Kawano, Shigeyuki

PY - 2012/10

Y1 - 2012/10

N2 - Chloroplasts of the unicellular green alga Nannochloris bacillaris Naumann cultured under nutrient-enriched conditions have multiple rings of FtsZ, a prokaryote-derived chloroplast division protein. We previously reported that synthesis of excess chloroplast DNA and formation of multiple FtsZ rings occur simultaneously. To clarify the role of multiple FtsZ rings in chloroplast division, we investigated chloroplast DNA synthesis and ring formation in cells cultured under various culture conditions. Cells transferred from a nutrient-enriched medium to an inorganic medium in the light showed a drop in cell division rate, a reduction in chloroplast DNA content, and changes in the shape of chloroplast nucleoids as cells divided. We then examined DNA synthesis by immunodetecting BrdU incorporated into DNA strands using the anti-BrdU antibody. BrdU-labeled nuclei were clearly observed in cells 48h after transfer into the inorganic medium, while only weak punctate signals were visible in the chloroplasts. In parallel, the number of FtsZ rings decreased from 6 to only 1. When the cells were transferred from an inorganic medium to a nutrient-enriched medium, the number of cells increased only slightly in the first 12h after transfer; after this time, however, they started to divide more quickly and increased exponentially. Chloroplast nucleoids changed from punctate to rod-like structures, and active chloroplast DNA synthesis and FtsZ ring formation were observed. On the basis of our results, we conclude that multiple FtsZ ring assembly and chloroplast DNA duplication under nutrient-rich conditions facilitate chloroplast division after transfer to oligotrophic conditions without further duplication of chloroplast DNA and formation of new FtsZ rings.

AB - Chloroplasts of the unicellular green alga Nannochloris bacillaris Naumann cultured under nutrient-enriched conditions have multiple rings of FtsZ, a prokaryote-derived chloroplast division protein. We previously reported that synthesis of excess chloroplast DNA and formation of multiple FtsZ rings occur simultaneously. To clarify the role of multiple FtsZ rings in chloroplast division, we investigated chloroplast DNA synthesis and ring formation in cells cultured under various culture conditions. Cells transferred from a nutrient-enriched medium to an inorganic medium in the light showed a drop in cell division rate, a reduction in chloroplast DNA content, and changes in the shape of chloroplast nucleoids as cells divided. We then examined DNA synthesis by immunodetecting BrdU incorporated into DNA strands using the anti-BrdU antibody. BrdU-labeled nuclei were clearly observed in cells 48h after transfer into the inorganic medium, while only weak punctate signals were visible in the chloroplasts. In parallel, the number of FtsZ rings decreased from 6 to only 1. When the cells were transferred from an inorganic medium to a nutrient-enriched medium, the number of cells increased only slightly in the first 12h after transfer; after this time, however, they started to divide more quickly and increased exponentially. Chloroplast nucleoids changed from punctate to rod-like structures, and active chloroplast DNA synthesis and FtsZ ring formation were observed. On the basis of our results, we conclude that multiple FtsZ ring assembly and chloroplast DNA duplication under nutrient-rich conditions facilitate chloroplast division after transfer to oligotrophic conditions without further duplication of chloroplast DNA and formation of new FtsZ rings.

KW - Chloroplast division

KW - Chloroplast DNA synthesis

KW - Chloroplast nucleoid

KW - FtsZ ring

KW - Nannochloris bacillaris

UR - http://www.scopus.com/inward/record.url?scp=84867217359&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=84867217359&partnerID=8YFLogxK

U2 - 10.1111/j.1529-8817.2012.01204.x

DO - 10.1111/j.1529-8817.2012.01204.x

M3 - Article

VL - 48

SP - 1187

EP - 1196

JO - Journal of Phycology

JF - Journal of Phycology

SN - 0022-3646

IS - 5

ER -