Chloroplast Protrusions inArisarum Proboscideum(L.) Savi

Bonzi, Laura Morassi; Fabbri, Fernando

doi:10.1080/00087114.1975.10796628

Cited by 6 publications

(3 citation statements)

References 23 publications

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“…The presence of mitochondria in chloroplasts [89]- [94] and detachment of mitochondria or mitochondrion-like bodies from chloroplasts [95] [96] [97] have been observed frequently in plant cells. However, these phenomena have largely been overlooked and whether the chloroplast-localized mitochondria were developed in or engulfed by the chloroplast remains controversial.…”

Section: Development Of Mitochondria In the Primitive Chloroplastsmentioning

confidence: 99%

De Novo Organelle Biogenesis in the Cyanobacterium TDX16 Released from the Green Alga Haematococcus pluvialis

Dong¹,

Xing²,

Han³

et al. 2020

CellBio

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It is believed that eukaryotes arise from prokaryotes, which means that organelles can form de novo in prokaryotes. Such events, however, had not been observed previously. Here, we report the biogenesis of organelles in the endosymbiotic cyanobacterium TDX16 (prokaryote) that was released from its senescent/necrotic host cell of green alga Haematococcus pluvialis (eukaryote).Microscopic observations showed that organelle biogenesis in TDX16 initiated with cytoplasm compartmentalization, followed by de-compartmentalization, DNA allocation, and re-compartmentalization, as such two composite organelles-the primitive chloroplast and primitive nucleus sequestering minor and major fractions of cellular DNA respectively were formed. Thereafter, the eukaryotic cytoplasmic matrix was built up from the matrix extruded from the primitive nucleus; mitochondria were assembled in and segregated from the primitive chloroplast, whereby the primitive nucleus and primitive chloroplast matured into the nucleus and chloroplast respectively. While mitochondria subsequently turned into double-membraned vacuoles after matrix degradation. Results of pigment analyses, 16S rRNA and genome sequencing revealed that TDX16 is a phycocyanin-containing cyanobacterium resembling Chroococcidiopsis thermalis, which had acquired 9,017,401 bp DNAs with 10,301 genes from its host. Accordingly, we conclude that organelle biogenesis in TDX16 is achieved by hybridizing the acquired eukaryotic DNAs with its own one and expressing the hybrid genome. The formation of organelles in cyanobacterium TDX16 is the first case of organelle biogenesis in prokaryotes observed so far, which sheds an unprecedented light on eukaryotes and their connections with prokaryotes, and thus has broad implications on biology.The transition of cyanobacterium TDX16 cells into green algal cells is the first case of prokaryote-to-eukaryote transition observed so far, which provides the opportunity and platform to solve the puzzle of organelle biogenesis in prokaryotic cells. Hence, this study aims to investigate how and why organelles form in cyanobacterium TDX16. Materials and Methods Strain and CultivationPure TDX16 cells were collected from the H. pluvialis cultures, in which all H. pluvialis cells burst and released TDX16 cells [11], and maintained in sterile BG-11 liquid medium [13] at 25˚C, 12 μmol photons m −2 •s −1 in the illumination incubator. Axenic TDX16 was prepared according to the method [14] with some modifications. Briefly, pure TDX16 culture was treated with antibiotics nystatin (100 μg/ml) and cycloheximide (150 μg/ml) for 18 h, then the culture was diluted 10 fold with sterile distilled water and plated onto BG-11 solid medium in petri dishes supplemented (w/v)with glucose (0.5%), peptone (0.3%) and yeast extracts (0.2%). The petri dishes were sealed with parafilm and incubated in an inverted position in the illumination incubator at 25˚C, 12 μmol photons m −2 •s −1 for one month. The colonies (Figure 4) were picked and transferred into autoclaved 250-ml flasks ...

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Section: Development Of Mitochondria In the Primitive Chloroplastsmentioning

confidence: 99%

De Novo Organelle Biogenesis in the Cyanobacterium TDX16 Released from the Green Alga Haematococcus pluvialis

Dong¹,

Xing²,

Han³

et al. 2020

CellBio

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“…During recent years FP-highlighted plastids and stromules have garnered a fair bit of attention but another contemporary undercurrent of contextual publications based on TEM studies has also existed and requires discussion. Several publications that predate the discovery and naming of stromules, presented double membrane bound stroma-filled protrusions that were simply called chloroplast protrusions (CP) (Bonzi and Fabbri, 1975 ; Lütz and Moser, 1977 ; Lütz, 1987 ; Bourett et al, 1999 ). Serial TEM sections of leaves in Ranunculus glacialis and O. digyna (Lütz and Moser, 1977 ; Lütz, 1987 ; Larcher et al, 1997 ; Lütz and Engel, 2007 ) showed that CP appear as broad or long, grana-free extensions and occasionally form pocket-like structures with mitochondria and microbody aggregates (Lütz and Engel, 2007 ).…”

Section: Chloroplast Protrusions and Stromules: An Artificial Distincmentioning

confidence: 99%

“…Nevertheless, the distinction appears quite artificial and a report of chloroplast extensions in bundle sheath cells in rice leaves used the terms CP and stromules interchangeably after realizing that the plastid extensions observed might be placed into either category (Sage and Sage, 2009 ). In addition the excellent transmission electron micrographs of plastids in Arisarum proboscideum (Bonzi and Fabbri, 1975 ) depicted protrusions that today might just as easily be labeled stromules. On the other hand reports published well after the term stromule was introduced (Köhler and Hanson, 2000 ) persisted in presenting narrow tubules as CP (Figures 2E, 4A in Holzinger et al, 2007a ; Figures 5.2D,F, 5.4C,E in Lütz et al, 2012 ).…”

Section: Chloroplast Protrusions and Stromules: An Artificial Distincmentioning

confidence: 99%

Fluorescent Protein Aided Insights on Plastids and their Extensions: A Critical Appraisal

et al. 2016

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Multi-colored fluorescent proteins targeted to plastids have provided new insights on the dynamic behavior of these organelles and their interactions with other cytoplasmic components and compartments. Sub-plastidic components such as thylakoids, stroma, the inner and outer membranes of the plastid envelope, nucleoids, plastoglobuli, and starch grains have been efficiently highlighted in living plant cells. In addition, stroma filled membrane extensions called stromules have drawn attention to the dynamic nature of the plastid and its interactions with the rest of the cell. Use of dual and triple fluorescent protein combinations has begun to reveal plastid interactions with mitochondria, the nucleus, the endoplasmic reticulum and F-actin and suggests integral roles of plastids in retrograde signaling, cell to cell communication as well as plant-pathogen interactions. While the rapid advances and insights achieved through fluorescent protein based research on plastids are commendable it is necessary to endorse meaningful observations but subject others to closer scrutiny. Here, in order to develop a better and more comprehensive understanding of plastids and their extensions we provide a critical appraisal of recent information that has been acquired using targeted fluorescent protein probes.

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Evolving Views on Plastid Pleomorphy

Delfosse

Wozny

Anderson

et al. 2018

Plant Cell Monographs

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Chloroplast Protrusions inArisarum Proboscideum(L.) Savi

Cited by 6 publications

References 23 publications

De Novo Organelle Biogenesis in the Cyanobacterium TDX16 Released from the Green Alga <i>Haematococcus pluvialis</i>

De Novo Organelle Biogenesis in the Cyanobacterium TDX16 Released from the Green Alga <i>Haematococcus pluvialis</i>

Fluorescent Protein Aided Insights on Plastids and their Extensions: A Critical Appraisal

Evolving Views on Plastid Pleomorphy

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Chloroplast Protrusions inArisarum Proboscideum(L.) Savi

Cited by 6 publications

References 23 publications

De Novo Organelle Biogenesis in the Cyanobacterium TDX16 Released from the Green Alga &lt;i&gt;Haematococcus pluvialis&lt;/i&gt;

De Novo Organelle Biogenesis in the Cyanobacterium TDX16 Released from the Green Alga &lt;i&gt;Haematococcus pluvialis&lt;/i&gt;

Fluorescent Protein Aided Insights on Plastids and their Extensions: A Critical Appraisal

Evolving Views on Plastid Pleomorphy

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Product

Resources

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De Novo Organelle Biogenesis in the Cyanobacterium TDX16 Released from the Green Alga <i>Haematococcus pluvialis</i>

De Novo Organelle Biogenesis in the Cyanobacterium TDX16 Released from the Green Alga <i>Haematococcus pluvialis</i>