Polarity, spatial organisation of cytoskeleton, and nuclear division in morphologically altered cells of Schizosaccharomyces pombe

1997 ◽  
Vol 43 (11) ◽  
pp. 991-998 ◽  
Author(s):  
M. Sipiczki ◽  
A. Grallert
Keyword(s):  
Cell Division ◽  
Cell Surface ◽  
Cell Polarity ◽  
Cell Morphology ◽  
Nuclear Division ◽  
Cell Envelope ◽  
Triple Mutant ◽  
Spatial Organisation ◽  
Mitosis And Meiosis

To gain more information about the determination of cell polarity and its relationship to the organisation of cytoskeleton, we have examined the mycelial mutant sep1-1 and the multinucleate multipolar syncytia of the triple mutant sep1-1 spl1-1 cdc4-8 by indirect immunofluorescence techniques. We have found that polarity is predetermined by the shape of the cell. During transition from mitosis to interphase the microtubules of the arising cytoplasmic cytoskeleton gradually form a basket-like pattern that reflects the curvatures of the cell envelope. The presumable growing poles, where actin accumulates, usually correlates with the sites where the cell tapers and the microtubules converge. However, no growth can be launched at these sites if the cell surface has not been properly processed. Mitosis and meiosis are not affected significantly by changes in cell morphology and polarity, but larger cells are less effective during sporulation. The azygotic asci produced by multinucleate syncytia frequently contain over 20 ascospores.Key words: cell division cycle, cytokinesis, cytoskeleton, fission yeast.

scholarly journals Phosphoinositide signaling plays a key role in cytokinesis

2006 ◽  
Vol 174 (4) ◽  
pp. 485-490 ◽  
Author(s):  
Chris Janetopoulos ◽  
Peter Devreotes
Keyword(s):  
Cell Division ◽  
Cell Polarity ◽  
Cell Morphology ◽  
Cell Shape ◽  
Phosphoinositide Signaling ◽  
Complex Series ◽  
Vital Functions ◽  
Cell Shape Changes ◽  
Shape Changes

To perform the vital functions of motility and division, cells must undergo dramatic shifts in cell polarity. Recent evidence suggests that polarized distributions of phosphatidylinositol 4,5-bisphosphate and phosphatidylinositol 3,4,5-trisphosphate, which are clearly important for regulating cell morphology during migration, also play an important role during the final event in cell division, which is cytokinesis. Thus, there is a critical interplay between the membrane phosphoinositides and the cytoskeletal cortex that regulates the complex series of cell shape changes that accompany these two processes.

scholarly journals Deficiency of RgpG Causes Major Defects in Cell Division and Biofilm Formation, and Deficiency of LytR-CpsA-Psr Family Proteins Leads to Accumulation of Cell Wall Antigens in Culture Medium by Streptococcus mutans

2017 ◽  
Vol 83 (17) ◽  
Author(s):  
Arpan De ◽  
Sumei Liao ◽  
Jacob P. Bitoun ◽  
Randy Roth ◽  
Wandy L. Beatty ◽  
...  
Keyword(s):  
Growth Rate ◽  
Cell Wall ◽  
Cell Division ◽  
Streptococcus Mutans ◽  
Biofilm Formation ◽  
Cell Envelope ◽  
Biosynthesis Pathway ◽  
Wild Type ◽  
Triple Mutant ◽  
Content Type

ABSTRACTStreptococcus mutansis known to possess rhamnose-glucose polysaccharide (RGP), a major cell wall antigen.S. mutansstrains deficient inrgpG, encoding the first enzyme of the RGP biosynthesis pathway, were constructed by allelic exchange. ThergpGdeficiency had no effect on growth rate but caused major defects in cell division and altered cell morphology. Unlike the coccoid wild type, thergpGmutant existed primarily in chains of swollen, “squarish” dividing cells. Deficiency ofrgpGalso causes significant reduction in biofilm formation (P< 0.01). Double and triple mutants with deficiency inbrpAand/orpsr, genes coding for the LytR-CpsA-Psr family proteins BrpA and Psr, which were previously shown to play important roles in cell envelope biogenesis, were constructed using thergpGmutant. There were no major differences in growth rates between the wild-type strain and thergpG brpAandrgpG psrdouble mutants, but the growth rate of thergpG brpA psrtriple mutant was reduced drastically (P< 0.001). Under transmission electron microscopy, both double mutants resembled thergpGmutant, while the triple mutant existed as giant cells with multiple asymmetric septa. When analyzed by immunoblotting, thergpGmutant displayed major reductions in cell wall antigens compared to the wild type, while little or no signal was detected with the double and triple mutants and thebrpAandpsrsingle mutants. These results suggest that RgpG inS. mutansplays a critical role in cell division and biofilm formation and that BrpA and Psr may be responsible for attachment of cell wall antigens to the cell envelope.IMPORTANCEStreptococcus mutans, a major etiological agent of human dental caries, produces rhamnose-glucose polysaccharide (RGP) as the major cell wall antigen. This study provides direct evidence that deficiency of RgpG, the first enzyme of the RGP biosynthesis pathway, caused major defects in cell division and morphology and reduced biofilm formation byS. mutans, indicative of a significant role of RGP in cell division and biofilm formation inS. mutans. These results are novel not only inS. mutans, but also other streptococci that produce RGP. This study also shows that the LytR-CpsA-Psr family proteins BrpA and Psr inS. mutansare involved in attachment of RGP and probably other cell wall glycopolymers to the peptidoglycan. In addition, the results also suggest that BrpA and Psr may play a direct role in cell division and biofilm formation inS. mutans. This study reveals new potential targets to develop anticaries therapeutics.

scholarly journals Engineering Cyanobacterial Cell Morphology for Enhanced Recovery and Processing of Biomass

2017 ◽  
Vol 83 (9) ◽  
Author(s):  
Adam Jordan ◽  
Jenna Chandler ◽  
Joshua S. MacCready ◽  
Jingcheng Huang ◽  
Katherine W. Osteryoung ◽  
...  
Keyword(s):  
Cell Division ◽  
Cell Morphology ◽  
Dynamic Range ◽  
Enhanced Recovery ◽  
Downstream Processing ◽  
Crop Species ◽  
Content Type ◽  
Alternative Crop ◽  
Cell Harvesting ◽  
Broad Dynamic Range

ABSTRACT Cyanobacteria are emerging as alternative crop species for the production of fuels, chemicals, and biomass. Yet, the success of these microbes depends on the development of cost-effective technologies that permit scaled cultivation and cell harvesting. Here, we investigate the feasibility of engineering cell morphology to improve biomass recovery and decrease energetic costs associated with lysing cyanobacterial cells. Specifically, we modify the levels of Min system proteins in Synechococcus elongatus PCC 7942. The Min system has established functions in controlling cell division by regulating the assembly of FtsZ, a tubulin-like protein required for defining the bacterial division plane. We show that altering the expression of two FtsZ-regulatory proteins, MinC and Cdv3, enables control over cell morphology by disrupting FtsZ localization and cell division without preventing continued cell growth. By varying the expression of these proteins, we can tune the lengths of cyanobacterial cells across a broad dynamic range, anywhere from an ∼20% increased length (relative to the wild type) to near-millimeter lengths. Highly elongated cells exhibit increased rates of sedimentation under low centrifugal forces or by gravity-assisted settling. Furthermore, hyperelongated cells are also more susceptible to lysis through the application of mild physical stress. Collectively, these results demonstrate a novel approach toward decreasing harvesting and processing costs associated with mass cyanobacterial cultivation by altering morphology at the cellular level. IMPORTANCE We show that the cell length of a model cyanobacterial species can be programmed by rationally manipulating the expression of protein factors that suppress cell division. In some instances, we can increase the size of these cells to near-millimeter lengths with this approach. The resulting elongated cells have favorable properties with regard to cell harvesting and lysis. Furthermore, cells treated in this manner continue to grow rapidly at time scales similar to those of uninduced controls. To our knowledge, this is the first reported example of engineering the cell morphology of cyanobacteria or algae to make them more compatible with downstream processing steps that present economic barriers to their use as alternative crop species. Therefore, our results are a promising proof-of-principle for the use of morphology engineering to increase the cost-effectiveness of the mass cultivation of cyanobacteria for various sustainability initiatives.

Inhibition of DNA synthesis and cell division by a cell surface sialoglycopeptide

1989 ◽  
Vol 139 (2) ◽  
pp. 269-274 ◽  
Author(s):  
Heideh Fattaey ◽  
Terry C. Johnson ◽  
Hsin-Hwei Chou
Keyword(s):  
Cell Division ◽  
Cell Surface ◽  
Dna Synthesis ◽  
A Cell ◽  
Inhibition Of Dna Synthesis

fumble Encodes a Pantothenate Kinase Homolog Required for Proper Mitosis and Meiosis in Drosophila melanogaster

Genetics ◽  
2001 ◽  
Vol 157 (3) ◽  
pp. 1267-1276
Author(s):  
Katayoun Afshar ◽  
Pierre Gönczy ◽  
Stephen DiNardo ◽  
Steven A Wasserman
Keyword(s):  
Cell Division ◽  
Chromosome Segregation ◽  
Cell Division Cycle ◽  
Protein Isoforms ◽  
Pantothenate Kinase ◽  
Male Germline ◽  
Dividing Cells ◽  
Mutant Cells ◽  
Mitosis And Meiosis

Abstract A number of fundamental processes comprise the cell division cycle, including spindle formation, chromosome segregation, and cytokinesis. Our current understanding of these processes has benefited from the isolation and analysis of mutants, with the meiotic divisions in the male germline of Drosophila being particularly well suited to the identification of the required genes. We show here that the fumble (fbl) gene is required for cell division in Drosophila. We find that dividing cells in fbl-deficient testes exhibit abnormalities in bipolar spindle organization, chromosome segregation, and contractile ring formation. Cytological analysis of larval neuroblasts from null mutants reveals a reduced mitotic index and the presence of polyploid cells. Molecular analysis demonstrates that fbl encodes three protein isoforms, all of which contain a domain with high similarity to the pantothenate kinases of A. nidulans and mouse. The largest Fumble isoform is dispersed in the cytoplasm during interphase, concentrates around the spindle at metaphase, and localizes to the spindle midbody at telophase. During early embryonic development, the protein localizes to areas of membrane deposition and/or rearrangement, such as the metaphase and cellularization furrows. Given the role of pantothenate kinase in production of Coenzyme A and in phospholipid biosynthesis, this pattern of localization is suggestive of a role for fbl in membrane synthesis. We propose that abnormalities in synthesis and redistribution of membranous structures during the cell division cycle underlie the cell division defects in fbl mutant cells.

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