scholarly journals A unique cell division machinery in the Archaea

2008 ◽  
Vol 105 (48) ◽  
pp. 18942-18946 ◽  
Author(s):  
A.-C. Lindas ◽  
E. A. Karlsson ◽  
M. T. Lindgren ◽  
T. J. G. Ettema ◽  
R. Bernander
Keyword(s):  
Cell Division ◽  
Unique Cell

scholarly journals FtsW activity and lipid II synthesis are required for recruitment of MurJ to midcell during cell division inEscherichia coli

2017 ◽  
Author(s):  
Xiaolong Liu ◽  
Nils Y. Meiresonne ◽  
Ahmed Bouhss ◽  
Tanneke den Blaauwen
Keyword(s):  
Cell Division ◽  
Cell Shape ◽  
Inescherichia Coli ◽  
E Coli ◽  
Lateral Membrane ◽  
Lipid Ii ◽  
Unique Cell ◽  
Septal Localization

AbstractPeptidoglycan (PG) is the unique cell shape-determining component of the bacterial envelope, and is a key target for antibiotics. PG synthesis requires the transmembrane movement of the precursor lipid II, and MurJ has been shown to provide this activity inE. coli.However, how MurJ functionsin vivohas not been reported. Here we show that MurJ localizes both in the lateral membrane and at midcell, and is recruited to midcell simultaneously with late-localizing divisome proteins and proteins MraY and MurG. MurJ septal localization is dependent on the presence of a complete and active divisome, lipid II synthesis and PBP3/FtsW activities. Inactivation of MurJ, either directly by mutation or through binding with MTSES, did not affect the midcell localization of MurJ. Our study visualizes MurJ localizationin vivoand reveals a possible mechanism of how MurJ functions during cell division, which gives possibilities for future investigations and further antibiotics developments.

scholarly journals Fussing about fission: defining variety among mainstream and exotic apicomplexan cell division modes

2020 ◽  
Author(s):  
Marc-Jan Gubbels ◽  
Caroline D. Keroack ◽  
Sriveny Dangoudoubiyam ◽  
Hanna L. Worliczek ◽  
Aditya S. Paul ◽  
...  
Keyword(s):  
Life Cycle ◽  
Cell Division ◽  
Opportunistic Infections ◽  
Historical Context ◽  
Binary Fission ◽  
Model Organisms ◽  
Babesia Bigemina ◽  
Offspring Number ◽  
Biological Studies ◽  
Unique Cell

AbstractCellular reproduction defines life, yet our textbook-level understanding of cell division is limited to a small number of model organisms centered around humans. The horizon on cell division variants is expanded here by advancing insights on the fascinating cell division modes found in the Apicomplexa, a key group of protozoan parasites. The Apicomplexa display remarkable variation in offspring number, whether karyokinesis follows each S/M-phase or not, and whether daughter cells bud in the cytoplasm or bud from the cortex. We find that the terminology used to describe the various manifestations of asexual apicomplexan cell division emphasizes either the number of offspring or site of budding, which are not directly comparable features and has led to confusion in the literature. Division modes have been primarily studied in two human pathogenic Apicomplexa, malaria-causing Plasmodium spp. and Toxoplasma gondii, a major cause of opportunistic infections. Plasmodium spp. divide asexually by schizogony, producing multiple daughters per division round through a cortical budding process, though at several life-cycle nuclear amplifications are not followed by karyokinesis. T. gondii divides by endodyogeny producing two internally budding daughters per division round. Here we add to this diversity in replication mechanisms by considering the cattle parasite Babesia bigemina and the pig parasite Cystoisospora suis. B. bigemina produces two daughters per division round by a ‘binary fission’ mechanism whereas C. suis produces daughters through both endodyogeny and multiple internal budding known as endopolygeny. In addition, we provide new data from the causative agent of equine protozoal myeloencephalitis (EPM), Sarcocystis neurona, which also undergoes endopolygeny but differs from C. suis by maintaining a single multiploid nucleus. Overall, we operationally define two principally different division modes: internal budding found in cyst-forming Coccidia (comprising endodyogeny and two forms of endopolygeny) and external budding found in the other parasites studied (comprising the two forms of schizogony, binary fission and multiple fission). Progressive insights into the principles defining the molecular and cellular requirements for internal versus external budding, as well as variations encountered in sexual stages are discussed. The evolutionary pressures and mechanisms underlying apicomplexan cell division diversification carries relevance across Eukaryota.Contribution to the FieldMechanisms of cell division vary dramatically across the Tree of Life, but the mechanistic basis has only been mapped for several model organisms. Here we present cell division strategies across Apicomplexa, a group of obligate intracellular parasites with significant impact on humans and domesticated animals. Asexual apicomplexan cell division is organized around assembly of daughter buds, but division forms differ in the cellular site of budding, number of offspring per division round, whether each S-phase follows karyokinesis and if mitotic rounds progress synchronously. This varies not just between parasites, but also between different life-cycle stages of a given species. We discuss the historical context of terminology describing division modes, which has led to confusion on how different modes relate to each other. Innovations in cell culture and genetics together with light microscopy advances have opened up cell biological studies that can shed light on this puzzle. We present new data for three division modes barely studied before. Together with existing data, we show how division modes are organized along phylogenetic lines and differentiate along external and internal budding mechanisms. We also discuss new insights into how the variations in division mode are regulated at the molecular level, and possess unique cell biological requirements.

The Ultrastructure of the Nuclear Events of Binary Fission in Paramecium bursaria and the Effects of Colchicine on Cell Division

1974 ◽  
Vol 32 ◽  
pp. 276-277
Author(s):  
L. M. Lewis
Keyword(s):  
Cell Division ◽  
Nuclear Envelope ◽  
Condensed Chromatin ◽  
Binary Fission ◽  
Paramecium Bursaria ◽  
Nuclear Events ◽  
Division Axis

The effects of colchicine on extranuclear microtubules associated with the macronucleus of Paramecium bursaria were studied to determine the possible role that these microtubules play in controlling the shape of the macronucleus. In the course of this study, the ultrastructure of the nuclear events of binary fission in control cells was also studied.During interphase in control cells, the micronucleus contains randomly distributed clumps of condensed chromatin and microtubular fragments. Throughout mitosis the nuclear envelope remains intact. During micronuclear prophase, cup-shaped microfilamentous structures appear that are filled with condensing chromatin. Microtubules are also present and are parallel to the division axis.

Stimulated Virus Production in Vinblastine and Cytochalasin-Induced Multinucleate Cells

1970 ◽  
Vol 28 ◽  
pp. 186-187
Author(s):  
Krishan Awtar
Keyword(s):  
Cell Division ◽  
Normal Cell ◽  
Virus Production ◽  
Multinucleate Cells ◽  
Daughter Cells ◽  
Cell Divisions ◽  
Nuclear Membranes ◽  
Division 2 ◽  
Vinblastine Sulfate

Exposure of cells to low sublethal but mitosis-arresting doses of vinblastine sulfate (Velban) results in the initial arrest of cells in mitosis followed by their subsequent return to an “interphase“-like stage. A large number of these cells reform their nuclear membranes and form large multimicronucleated cells, some containing as many as 25 or more micronuclei (1). Formation of large multinucleate cells is also caused by cytochalasin, by causing the fusion of daughter cells at the end of an otherwise .normal cell division (2). By the repetition of this process through subsequent cell divisions, large cells with 6 or more nuclei are formed.

Confocal microscopy of the cytoskeleton in living plant cells following microinjection of fluorescent probes

1993 ◽  
Vol 51 ◽  
pp. 130-131
Author(s):  
Ann Cleary
Keyword(s):  
Cell Division ◽  
Fluorescent Probes ◽  
Actin Filaments ◽  
Intracellular Transport ◽  
Cell Structure ◽  
Plant Cells ◽  
Cell Plate ◽  
Cell Cortex ◽  
Living Plant ◽  
Rhodamine Phalloidin

Microinjection of fluorescent probes into living plant cells reveals new aspects of cell structure and function. Microtubules and actin filaments are dynamic components of the cytoskeleton and are involved in cell growth, division and intracellular transport. To date, cytoskeletal probes used in microinjection studies have included rhodamine-phalloidin for labelling actin filaments and fluorescently labelled animal tubulin for incorporation into microtubules. From a recent study of Tradescantia stamen hair cells it appears that actin may have a role in defining the plane of cell division. Unlike microtubules, actin is present in the cell cortex and delimits the division site throughout mitosis. Herein, I shall describe actin, its arrangement and putative role in cell plate placement, in another material, living cells of Tradescantia leaf epidermis.The epidermis is peeled from the abaxial surface of young leaves usually without disruption to cytoplasmic streaming or cell division. The peel is stuck to the base of a well slide using 0.1% polyethylenimine and bathed in a solution of 1% mannitol +/− 1 mM probenecid.

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