scholarly journals Macromolecules released into the culture medium during the vegetative cell cycle of the unicellular green alga Chlamydomonas reinhardii

1985 ◽  
Vol 226 (1) ◽  
pp. 259-268 ◽  
Author(s):  
J Voigt
Keyword(s):  
Cell Cycle ◽  
Cell Wall ◽  
Cell Growth ◽  
Mother Cell ◽  
Culture Medium ◽  
Cell Enlargement ◽  
Chlamydomonas Reinhardii ◽  
Time Period ◽  
Protein Components ◽  
Mother Cell Wall

The culture medium of growing Chlamydomonas reinhardii cells contains hydroxyproline-rich glycoproteins, which are mainly liberated during release of the zoospores from the mother-cell wall. Pulse-labelling studies with [3H]proline and [35S]methionine have been performed in order to detect the protein components released by synchronously growing cells at different stages of the cell cycle. When either [3H]proline or [35S]methionine were applied during the phase of cell growth, radioactive label appeared in the released macromolecules after a lag period of 40 min, whereas incorporation into the insoluble part of the cell wall was delayed only by 20 min. When applied at the end of the growth phase, e.g. 13 h after beginning of the illumination period, the radioactive amino acids were incorporated into the cell wall, but radioactive labelling of macromolecules released into the culture medium could not be detected before the zoospores were liberated from the mother-cell wall. Maximal incorporation of [3H]proline and [35S]methionine into the insoluble part of the cell wall was observed during cell division, but essentially no radioactively-labelled macromolecules were released into the culture medium during this time period. Analysis of the macromolecules, which were liberated during cell enlargement, by sodium dodecyl sulphate/polyacrylamide-gel electrophoresis revealed distinct radioactive bands, which were differentially labelled with [3H]proline and [35S]methionine. Among the macromolecules released into the culture medium during cell growth, a component of an apparent Mr 35 000 was preferentially labelled with [3H]proline. This component was also detected after labelling with [35S]methionine, but components of an apparently higher Mr were more prominent after labelling with [35S]methionine. Macromolecules released during the cell-enlargement period of synchronously growing cultures in the presence of [3H]proline contained radioactively-labelled hydroxyproline in addition to proline. These results show that, during cell-wall growth, specific protein components are released into the culture medium and that at least one of these components contains large amounts of proline and hydroxyproline. At least some of these macromolecules seem to be constituents of the cell wall, because during pulse-chase experiments radioactively-labelled macromolecules appeared in the culture medium mainly during the time period when the specific radioactivity of the insoluble inner-cell-wall layer decreased.

Biosynthesis and Turnover of Cell Wall Glycoproteins during the Vegetative Cell Cycle of Chlamydomonas reinhardii

1986 ◽  
Vol 41 (9-10) ◽  
pp. 885-896 ◽  
Author(s):  
Jürgen Voigt
Keyword(s):  
Cell Cycle ◽  
Cell Wall ◽  
Vegetative Cell ◽  
Wall Material ◽  
Cell Wall Material ◽  
Cell Enlargement ◽  
Chlamydomonas Reinhardii ◽  
Soluble Cell ◽  
Time Period ◽  
Wall Components

Abstract Biosynthesis and turnover of the different cell wall components have been studied during the vegetative cell cycle of Chlamydomonas reinhardii by pulse-labelling with [3H]proline and [35S]methionine and by pulse-chase experiments. Two phases of biosynthesis of insoluble cell wall material could be distinguished: 1. de novo synthesis of the daughter cell walls during cytokinesis and 2. cell wall enlargement during cell growth. During the cell enlargement period, a turnover of the insoluble wall component was observed. The released fragments were found to be accumulated in the culture medium. The LiCl-soluble cell wall glycoproteins were found to be precursors of the insoluble cell wall layer. Biosynthesis of the LiCl-soluble cell wall glycoproteins was observed mainly during the time period between cytokinesis and the end of the following cell enlargement period. Labelling of all the cell wall components was found to be strongly reduced during the time period between the end of the growth phase and cytokinesis. During cytokinesis, labelling of the insoluble cell wall material preceded the incorporation of radioactive precursors into the LiCl-soluble wall fraction.

Cell Volume and the Control of the Chlamydomonas Cell Cycle

1982 ◽  
Vol 54 (1) ◽  
pp. 173-191 ◽  
Author(s):  
R. A. CRAIGIE ◽  
T. CAVALIER-SMITH
Keyword(s):  
Cell Cycle ◽  
Cell Wall ◽  
Cell Division ◽  
Simple Model ◽  
Cell Volume ◽  
Mother Cell ◽  
Dark Period ◽  
Size Fractions ◽  
Daughter Cells ◽  
Mother Cell Wall

Chlamydomonas reinhardii divides by multiple fission to produce 2n daughter cells per division burst, where n is an integer. By separating predivision cells from synchronous cultures into fractions of differing mean cell volumes, and electronically measuring the numbers and volume distributions of the daughter cells produced by the subsequent division burst, we have shown that n is determined by the volume of the parent cell. Control of n can occur simply, if after every cell division the daughter cells monitor their volume and divide again if, and only if, their volume is greater than a fixed minimum value. In cultures synchronized by 12-h light/12-h dark cycles, the larger parent cells divide earlier in the dark period than do smaller cells. This has been shown by two independent methods: (1) by separating cells into different size fractions by Percoll density-gradient centrifugation and using the light microscope to see when they divide; and (2) by studying changes in the cell volume distribution of unfractioned cultures. Since daughter cells remain within the mother-cell wall for some hours after cell division, and cell division causes an overall swelling of the mother-cell wall, the timing of division can be determined electronically by measuring this increase in cell volume that occurs in the dark period in the absence of growth; we find that cells at the large end of the size distribution range undergo this swelling first, and are then followed by successively smaller size fractions. A simple model embodying a sizer followed by a timer gives a good quantitative fit to these data for 12-h light/12-h dark cycles if cell division occurs 12-h after attaining a critical volume of approximately 140 μm3. However, this simple model is called into question by our finding that alterations in the length of the light period alter the rate of progress towards division even of cells that have attained their critical volume. We discuss the relative roles of light and cell volume in the control of division timing in the Chlamydomonas cell cycle.

scholarly journals Phylogenetic and comparative functional analysis of the cell-separation α-glucanase Agn1p in Schizosaccharomyces

Microbiology ◽  
2014 ◽  
Vol 160 (6) ◽  
pp. 1063-1074 ◽  
Author(s):  
Matthias Sipiczki ◽  
Anita Balazs ◽  
Aniko Monus ◽  
Laszlo Papp ◽  
Anna Horvath ◽  
...  
Keyword(s):  
Cell Wall ◽  
Schizosaccharomyces Pombe ◽  
Fission Yeast ◽  
Mother Cell ◽  
Cell Separation ◽  
Yeast Cells ◽  
Glycoside Hydrolase Family ◽  
Binding Domains ◽  
Yeast Phase ◽  
Mother Cell Wall

The post-cytokinetic separation of cells in cell-walled organisms involves enzymic processes that degrade a specific layer of the division septum and the region of the mother cell wall that edges the septum. In the fission yeast Schizosaccharomyces pombe, the 1,3-α-glucanase Agn1p, originally identified as a mutanase-like glycoside hydrolase family 71 (GH71) enzyme, dissolves the mother cell wall around the septum edge. Our search in the genomes of completely sequenced fungi identified GH71 hydrolases in Basidiomycota, Taphrinomycotina and Pezizomycotina, but not in Saccharomycotina. The most likely Agn1p orthologues in Pezizomycotina species are not mutanases having mutanase-binding domains, but experimentally non-characterized hypothetical proteins that have no carbohydrate-binding domains. The analysis of the GH71 domains corroborated the phylogenetic relationships of the Schizosaccharomyces species determined by previous studies, but suggested a closer relationship to the Basidiomycota proteins than to the Ascomycota proteins. In the Schizosaccharomyces genus, the Agn1p proteins are structurally conserved: their GH71 domains are flanked by N-terminal secretion signals and C-terminal sequences containing the conserved block YNFNAY/HTG. The inactivation of the agn1Sj gene in Schizosaccharomyces japonicus, the only true dimorphic member of the genus, caused a severe cell-separation defect in its yeast phase, but had no effect on the hyphal growth and yeast-to-mycelium transition. It did not affect the mycelium-to-yeast transition either, only delaying the separation of the yeast cells arising from the fragmenting hyphae. The heterologous expression of agn1Sj partially rescued the separation defect of the agn1Δ cells of Schizosaccharomyces pombe. The results presented indicate that the fission yeast Agn1p 1,3-α-glucanases of Schizosaccharomyces japonicus and Schizosaccharomyces pombe share conserved functions in the yeast phase.

scholarly journals On a Malay Form of Chlorococcum humicola (Näg.), Rabenh

1919 ◽  
Vol 44 (299) ◽  
pp. 473-482 ◽  
Author(s):  
B. Muriel Bristol
Keyword(s):  
Cell Wall ◽  
Mother Cell ◽  
Cell Walls ◽  
Starch Granules ◽  
Red Pigment ◽  
Vegetative Cells ◽  
Daughter Cells ◽  
Set Up ◽  
Mother Cell Wall ◽  
Adult Cells

Summary The material described has been obtained from cultures of a sample of dried soil, which was sent from the Malay States about two years before the cultures were set up. The vegetative cells are spherical or subspherical, solitary or collected together into mucilaginous strata, very variable in size, being from 20–80 μ in diameter, each with a thin cellulose cell-wall and a single parietal chloroplast containing from one to several pyrenoids and numerous starch granules. In adult cells a quantity of yellow oil is stored, in which a bright red pigment is often dissolved. The cytoplasm is reticulate. The young cells contain a single minute nucleus and one pyrenoid, both of which multiply by repeated division so that the adult cells are cœnocytic with many pyrenoids. Propagation takes place, by successive bipartition of the contents of the mother-cell, into 8–16 or numerous biciliate zoogonidia which may develop asexually or may act as facultative gametes. In both cases direct development into vegetative cells takes place. Aplanospore-formation may also take place, preceded by the multiplication by constriction of the nuclei of the mother-cell. The aplanospores remain imbedded in a mucous stratum, and enter into a palmelloid state in which further bipartitions may take place. Eventually, the palmelloid cells either acquire cilia and behave as normal zoogonidia or they develop directly into vegetative cells. True vegetative division does not take place, but the cell-contents may divide into two daughter-cells which immediately acquire new cell-walls and are set free as vegetative cells by the dissolution of the mother-cell-wall. Chloroaoccum humicola, differing in no essential particulars from that in the Malay soil, has been found to occur almost universally in English soils. The limit of its resistance against desiccation and of its retention of vitality has been shown, by investigations on long-dried English soils, to lie somewhere between seventy and eighty years. In conclusion, I wish to express my thanks to Professor G. S. West for his valuable help throughout this work.

Evaluating an in vitro culture system of bovine uterine and oviduct epithelial cells for subsequent embryo co-culture

1992 ◽  
Vol 4 (5) ◽  
pp. 573 ◽  
Author(s):  
JK Thibodeaux ◽  
MW Myers ◽  
LL Goodeaux ◽  
Y Menezo ◽  
JD Roussel ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Cell Growth ◽  
Epithelial Cell ◽  
Epithelial Cells ◽  
Growth Rates ◽  
Culture System ◽  
Culture Medium ◽  
Growth Patterns ◽  
Oviduct Epithelial Cells

Three experiments were conducted to evaluate the effects of culture medium and incubation temperature on bovine uterine and oviduct epithelial cell growth, so that the most efficient combination could then be used to develop a co-culture system for bovine embryos. In the first experiment, uterine and oviduct epithelial cells at either the second or third subpassage were incubated for 8 days at 37 degrees C with 5% CO2 in Tissue Culture Medium-199, CMRL-1066, Minimal Essential Medium, Menezo's B2 or Ham's F-12 medium. In addition to plotting growth curves of cell populations, the cell cycle was monitored for 8 days by flow cytometry. Uterine and oviduct epithelial cells incubated in CMRL-1066 exhibited the highest growth rates during the 8-day culture period. However, there were no differences in cell cycle analysis among treatment groups during the incubation period. In the second experiment, CMRL-1066 medium was used to evaluate growth and proliferation of uterine and oviduct epithelial cells incubated at 37 degrees C or 39 degrees C; temperature had no significant effect on growth rates or proliferation rates for either uterine or oviduct cells during the 8-day incubation. In the third experiment, the more promising culture media for epithelial cell culture studies were chosen for in vitro maturation and subsequent in vitro fertilization (IVF) of bovine oocytes. Early cleavage-stage embryos produced by IVF procedures were subsequently cultured in vitro for 7 days in medium alone or with oviduct epithelial cells. In this study, the culture medium did not influence fertilization or cleavage rates. However, more embryos co-cultured with oviduct epithelial cells were considered viable after 7 days of incubation compared with embryos incubated in medium alone. These results indicate that various incubation conditions can influence the growth of bovine uterine and oviduct epithelial cells in vitro. However, in spite of changes in cell growth patterns, there does not appear to be a change in their embryotropic capabilities in vitro.

Haustorial mother cell development by Uromyces vignae on collodion membranes

1988 ◽  
Vol 66 (4) ◽  
pp. 736-741 ◽  
Author(s):  
Michèle C. Heath ◽  
C. J. Perumalla
Keyword(s):  
Cell Wall ◽  
Mother Cell ◽  
Rust Fungus ◽  
Potential Binding ◽  
Disulphonic Acid ◽  
Uromyces Vignae ◽  
Mother Cells ◽  
Chloroform Methanol ◽  
Infection Hypha ◽  
Mother Cell Wall

The development of infection structures by the rust fungus Uromyces vignae was observed on oil-containing collodion membranes. About 40% of infection hyphae formed a haustorial mother cell, but this structure commonly senesced and died more rapidly than the infection hypha to which it was attached. These data suggest that the continued development of the haustorial mother cell requires some component normally provided by the host plant. Before they died, many haustorial mother cells apparently formed the thickened region of the wall which normally is traversed by the penetration peg during haustorium formation. Such a peg was observed in the centre of up to 40% of these thickened regions. However, no pegs protruded beyond the haustorial mother cell far enough to be called a haustorial neck. The thickened region of the haustorial mother cell wall could be differentiated from the rest of the wall by its lack of fluorescence under ultraviolet irradiation when mounted in Calcofluor or SITS (4-acetomido-4′-iso-thiocyanatostilbene-2,2′-disulphonic acid). Treatment with alkali, acid, chloroform–methanol, protease, and laminarinase did not affect this differential fluorescence, and the haustorial mother cell wall stained uniformly for proteins, carbohydrates, and chitin. Since Calcofluor normally binds to chitin, these data suggest that the thickened region of the haustorial mother cell wall may physically exclude the dye or may contain potential binding sites that are masked by other wall components.

RELATIONSHIP BETWEEN PRESENCE OF A MOTHER CELL WALL AND SPECIATION IN THE UNICELLULAR MICROALGANANNOCHLORIS(CHLOROPHYTA)1

2003 ◽  
Vol 39 (1) ◽  
pp. 172-184 ◽  
Author(s):  
Maki Yamamoto ◽  
Hisayoshi Nozaki ◽  
Yutaka Miyazawa ◽  
Tomojiro Koide ◽  
Shigeyuki Kawano
Keyword(s):  
Cell Wall ◽  
Mother Cell ◽  
Mother Cell Wall

scholarly journals Mkh1, a MEK kinase required for cell wall integrity and proper response to osmotic and temperature stress in Schizosaccharomyces pombe.

1997 ◽  
Vol 17 (7) ◽  
pp. 3508-3519 ◽  
Author(s):  
A S Sengar ◽  
N A Markley ◽  
N J Marini ◽  
D Young
Keyword(s):  
Cell Cycle ◽  
Cell Wall ◽  
Cell Growth ◽  
Stationary Phase ◽  
Cell Morphology ◽  
Cell Shape ◽  
Catalytic Domain ◽  
Salt Resistance ◽  
Cell Wall Integrity ◽  
Phase Arrest

We have identified a Schizosaccharomyces pombe gene, mkh1, that encodes a MEK kinase (MEKK) homolog. The coding region of mkh1 is contained within a single exon encoding a 1,116-amino-acid protein. The putative catalytic domain of Mkh1 is 54% identical to the catalytic domain of S. cerevisiae Bck1, the most closely related protein. Deletion of mkh1 did not significantly affect cell growth or division under standard conditions. However, mkh1delta cell growth was inhibited by high KCl or NaCl concentrations. mkh1delta cells required a longer time to reenter the cell cycle after prolonged stationary-phase arrest. Also, mkh1delta cells exhibited a round cell shape, while overexpression of Mkh1 resulted in an elongated cell shape. mkh1delta cells exhibited a more dramatic phenotype when grown in nutrient-limiting conditions at high temperature or in hyperosmotic medium. In such conditions, completion of cytokinesis was inhibited, resulting in the growth of pseudohyphal filaments with multiple septa and nuclei. Also, mkh1delta cells were hypersensitive to beta-glucanase treatment. Together these results suggest that Mkh1 regulates cell morphology, cell wall integrity, salt resistance, cell cycle reentry from stationary-phase arrest, and filamentous growth in response to stress. These phenotypes are essentially identical to those exhibited by cells lacking Pmk1/Spm1, a recently identified mitogen-activated protein kinase. Our evidence suggests that Pmk1/Spm1 acts downstream from Mkh1 in a common pathway. Our results also suggest that Mkh1 and Pck2 act independently to maintain cell wall integrity, cell morphology, and salt resistance but act in opposition to regulate filamentous growth.

scholarly journals Mother Cell Wall Cleavage during Filament Formation in Stichococcus bacillaris (Trebouxiophyceae, Chlorophyta)

CYTOLOGIA ◽  
2016 ◽  
Vol 81 (1) ◽  
pp. 35-39 ◽  
Author(s):  
Maki Yamamoto ◽  
Shinji Handa ◽  
Masanobu Kawachi ◽  
Shinichi Miyamura ◽  
Tamotsu Nagumo ◽  
...  
Keyword(s):  
Cell Wall ◽  
Mother Cell ◽  
Filament Formation ◽  
Stichococcus Bacillaris ◽  
Mother Cell Wall
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