scholarly journals REGULATION OF MICROTUBULES IN TETRAHYMENA

1973 ◽  
Vol 56 (2) ◽  
pp. 458-465 ◽  
Author(s):  
Norman E. Williams ◽  
E. Marlo Nelsen
Keyword(s):  
Basal Body ◽  
De Novo ◽  
Basal Bodies ◽  
De Novo Synthesis

Experiments are reported which were designed to test for induced synthesis of microtubule proteins associated with the rapid proliferation of basal bodies and associated intracytoplasmic microtubules which occurs during oral replacement in Tetrahymena. None was found. Instead, it is shown that these structures can be formed with de novo synthesis of as little as 6% of their microtubule proteins. It is suggested that basal body proliferation may be controlled by synthesis of morphogenetic regulator proteins.

scholarly journals THE DEVELOPMENT OF BASAL BODIES AND FLAGELLA IN ALLOMYCES ARBUSCULUS

1964 ◽  
Vol 23 (2) ◽  
pp. 339-354 ◽  
Author(s):  
Fernando L. Renaud ◽  
Hewson Swift
Keyword(s):  
Electron Microscope ◽  
Basal Body ◽  
De Novo ◽  
The Other ◽  
Basal Bodies ◽  
Distilled Water ◽  
Vegetative Hypha ◽  
Original Length ◽  
Large Primary ◽  
Hyphal Tip

The development of basal bodies and flagella in the water mold Allomyces arbusculus has been studied with the electron microscope. A small pre-existing centriole, about 160 mµ in length, was found in an inpocketing of the nuclear membrane in the vegetative hypha. Thus, formation of a basal body does not occur de novo. When the hyphal tip started to differentiate into gametangia, the centrioles were found to exist in pairs. One of the members of the pair then grew distally to more than three times its original length, whereas the other remained the same size. The larger centriole would correspond to the basal body of a future gamete. Gametogenesis was usually induced by transferring a "ripe" culture to distilled water. Shortly after this was done, a few vesicles were pinched off from the cell membrane of the gametangium and came in contact with the basal body. Apparently, they fused and formed a large primary vesicle. The flagellum then started to grow by invaginating into it. Flagellar fibers were evident from the very beginning. As the flagellum grew so did the vesicle by fusion with secondary vesicles, thus coming to form the flagellar sheath. The different stages of flagellar morphogenesis are described and the possible interrelationships with other processes are discussed.

scholarly journals De novo formation of basal bodies in Naegleria gruberi

2005 ◽  
Vol 169 (5) ◽  
pp. 719-724 ◽  
Author(s):  
Hong-Kyung Kim ◽  
Jeong-Gu Kang ◽  
Shigehiko Yumura ◽  
Charles J. Walsh ◽  
Jin Won Cho ◽  
...  
Keyword(s):  
Western Blotting ◽  
Basal Body ◽  
Gel Electrophoresis ◽  
De Novo ◽  
Myosin Ii ◽  
Basal Bodies ◽  
2D Gel Electrophoresis ◽  
2D Gel ◽  
Naegleria Gruberi

The de novo formation of basal bodies in Naegleria gruberi was preceded by the transient formation of a microtubule (MT)-nucleating complex containing γ-tubulin, pericentrin, and myosin II complex (GPM complex). The MT-nucleating activity of GPM complexes was maximal just before the formation of visible basal bodies and then rapidly decreased. The regulation of MT-nucleating activity of GPM complexes was accomplished by a transient phosphorylation of the complex. Inhibition of dephosphorylation after the formation of basal bodies resulted in the formation of multiple flagella. 2D-gel electrophoresis and Western blotting showed a parallel relationship between the MT-nucleating activity of GPM complexes and the presence of hyperphosphorylated γ-tubulin in the complexes. These data suggest that the nucleation of MTs by GPM complexes precedes the de novo formation of basal bodies and that the regulation of MT-nucleating activity of GPM complexes is essential to the regulation of basal body number.

scholarly journals Emerging Picture of Deuterosome-Dependent Centriole Amplification in MCCs

Cells ◽  
2018 ◽  
Vol 7 (10) ◽  
pp. 152 ◽  
Author(s):  
Umama Shahid ◽  
Priyanka Singh
Keyword(s):  
Basal Body ◽  
De Novo ◽  
Super Resolution ◽  
Basal Bodies ◽  
Parallel Pathways ◽  
Multiciliated Cells ◽  
Dependent Pathway ◽  
Microtubule Structure

Multiciliated cells (MCCs) have several hair-like structures called cilia, which are required to propel substances on their surface. A cilium is organized from a basal body which resembles a hollow microtubule structure called a centriole. In terminally differentiated MCCs, hundreds of new basal bodies/centrioles are formed via two parallel pathways: the centriole- and deuterosome-dependent pathways. The deuterosome-dependent pathway is also referred to as “de novo” because unlike the centriole-dependent pathway which requires pre-existing centrioles, in the de novo pathway multiple new centrioles are organized around non-microtubule structures called deuterosomes. In the last five years, some deuterosome-specific markers have been identified and concurrent advancements in the super-resolution techniques have significantly contributed to gaining insights about the major stages of centriole amplification during ciliogenesis. Altogether, a new picture is emerging which also challenges the previous notion that deuterosome pathway is de novo. This review is primarily focused on studies that have contributed towards the better understanding of deuterosome-dependent centriole amplification and presents a developing model about the major stages identified during this process.

scholarly journals Naegleria gruberi De Novo Basal Body Assembly Occurs via Stepwise Incorporation of Conserved Proteins

2010 ◽  
Vol 9 (6) ◽  
pp. 860-865 ◽  
Author(s):  
Lillian K. Fritz-Laylin ◽  
Zoe June Assaf ◽  
Sean Chen ◽  
W. Zacheus Cande
Keyword(s):  
Basal Body ◽  
De Novo ◽  
Unicellular Eukaryote ◽  
Basal Bodies ◽  
Microtubule Cytoskeleton ◽  
Cytoplasmic Microtubule ◽  
Content Type ◽  
Genes Encoding ◽  
Associated Proteins ◽  
Naegleria Gruberi

ABSTRACT Centrioles and basal bodies are discrete structures composed of a cylinder of nine microtubule triplets and associated proteins. Metazoan centrioles can be found at mitotic spindle poles and are called basal bodies when used to organize microtubules to form the core structure of flagella. Naegleria gruberi, a unicellular eukaryote, grows as an amoeba that lacks a cytoplasmic microtubule cytoskeleton. When stressed, Naegleria rapidly (and synchronously) differentiates into a flagellate, forming a complete cytoplasmic cytoskeleton de novo, including two basal bodies and flagella. Here, we show that Naegleria has genes encoding conserved centriole proteins. Using novel antibodies, we describe the localization of three centrosomal protein homologs (SAS-6, γ-tubulin, and centrin-1) during the assembly of the flagellate microtubule cytoskeleton. We also used these antibodies to show that Naegleria expresses the proteins in the same order as their incorporation into basal bodies, with SAS-6 localizing first, followed by centrin and finally γ-tubulin. The similarities between basal body assembly in Naegleria and centriole assembly in animals indicate that mechanisms of assembly, as well as structure, have been conserved throughout eukaryotic evolution.

The Spindle as a Basal Body Distributor

1970 ◽  
Vol 7 (1) ◽  
pp. 65-89
Author(s):  
M. FRIEDLÄNDER ◽  
J. WAHRMAN
Keyword(s):  
Cell Cycle ◽  
Endoplasmic Reticulum ◽  
Basal Body ◽  
De Novo ◽  
The State ◽  
Basal Bodies ◽  
Metaphase Chromosomes ◽  
Silk Moth ◽  
Combined Mechanism

The spindle of metazoan cells functions as a dual distributor that guarantees the accurate segregation of both chromosomes and centrioles (basal bodies). This combined mechanism may have evolved from the separate distribution devices for chromosomes and basal bodies found in Protozoa. Typical eupyrene spermatocytes of the silk moth were compared with atypical apyrene spermatocytes. (a) Long microtubules, persisting during centriolar movements, develop in the meiotic prophases in continuity with the centrioles (b) There is no longer a centriole-microtubule continuity at metaphase-anaphase (c) Spindles comprise microtubules and endoplasmic reticulum (ER). The microtubules form a barrel-shaped structure terminating far in front of the centrioles. The two types of spermatocytes differ in the structure of the ER, which is vesicular in the eupyrene and lamellar in the apyrene line. It is suggested that the ER influences the anaphase movement of chromosomes, (d) The chromosomes lack localized centromeres. Microtubules penetrate all along the polar faces of the eupyrene metaphase chromosomes. The apyrene chromosomes form irregular blocks that are penetrated by microtubules all around their periphery, (e) The centriole comprises 3 concentric zones. Typical changes in the centriole are correlated with changes in the cell cycle. Replication, de novo formation and disappearance of centrioles are manifestations of the state of flux of the microtubules.

Ciliary coordination in newt lung cells requires microtubule-based linkages between basal bodies: A correlative light and EM study

1992 ◽  
Vol 50 (1) ◽  
pp. 570-571
Author(s):  
Robert Hard ◽  
Gerald Rupp ◽  
Matthew L. Withiam-Leitch ◽  
Lisa Cardamone
Keyword(s):  
Basal Body ◽  
Untreated Control ◽  
Beat Frequency ◽  
Primary Cultures ◽  
Living Cells ◽  
Power Stroke ◽  
Ultrastructural Changes ◽  
Lung Cells ◽  
Basal Bodies ◽  
Ciliated Cells

In a coordinated field of beating cilia, the direction of the power stroke is correlated with the orientation of basal body appendages, called basal feet. In newt lung ciliated cells, adjacent basal feet are interconnected by cold-stable microtubules (basal MTs). In the present study, we investigate the hypothesis that these basal MTs stabilize ciliary distribution and alignment. To accomplish this, newt lung primary cultures were treated with the microtubule disrupting agent, Colcemid. In newt lung cultures, cilia normally disperse in a characteristic fashion as the mucociliary epithelium migrates from the tissue explant. Four arbitrary, but progressive stages of dispersion were defined and used to monitor this redistribution process. Ciliaiy beat frequency, coordination, and dispersion were assessed for 91 hrs in untreated (control) and treated cultures. When compared to controls, cilia dispersed more rapidly and ciliary coordination decreased markedly in cultures treated with Colcemid (2 mM). Correlative LM/EM was used to assess whether these effects of Colcemid were coupled to ultrastructural changes. Living cells were defined as having coordinated or uncoordinated cilia and then were processed for transmission EM.

Characterization of Monocyte-Associated Factor V

1993 ◽  
Vol 70 (02) ◽  
pp. 273-280 ◽  
Author(s):  
Janos Kappelmayer ◽  
Satya P Kunapuli ◽  
Edward G Wyshock ◽  
Robert W Colman
Keyword(s):  
Monoclonal Antibody ◽  
Light Chain ◽  
Peripheral Blood ◽  
De Novo ◽  
Factor V ◽  
Blood Monocytes ◽  
De Novo Synthesis ◽  
Hep G2 ◽  
Hep G2 Cells ◽  
Peripheral Blood Monocytes

SummaryWe demonstrate that in addition to possessing binding sites for intact factor V (FV), unstimulated peripheral blood monocytes also express activated factor V (FVa) on their surfaces. FVa was identified on the monocyte surface by monoclonal antibody B38 recognizing FVa light chain and by human oligoclonal antibodies H1 (to FVa light chain) and H2 (to FVa heavy chain) using immunofluorescence microscopy and flow cytometry. On Western blots, partially cleaved FV could be identified as a 220 kDa band in lysates of monocytes. In addition to surface expression of FVa, monocytes also contain intracellular FV as detected only after permeabilization by Triton X-100 by monoclonal antibody B10 directed specifically to the Cl domain not present in FVa. We sought to determine whether the presence of FV in peripheral blood monocytes is a result of de novo synthesis.Using in situ hybridization, no FV mRNA could be detected in monocytes, while in parallel control studies, factor V mRNA was detectable in Hep G2 cells and CD18 mRNA in monocytes. In addition, using reverse transcriptase and the polymerase chain reaction, no FV mRNA was detected in mononuclear cells or in U937 cells, but mRNA for factor V was present in Hep G2 cells using the same techniques. These data suggest that FV is present in human monocytes, presumably acquired by binding of plasma FV, and that the presence of this critical coagulation factor is not due to de novo synthesis.

Platelets Stimulate Thromboplastin Synthesis in Human Endothelial Cells

1983 ◽  
Vol 49 (02) ◽  
pp. 069-072 ◽  
Author(s):  
U L H Johnsen ◽  
T Lyberg ◽  
K S Galdal ◽  
H Prydz
Keyword(s):  
Endothelial Cells ◽  
De Novo ◽  
Umbilical Vein ◽  
Time Dependent ◽  
De Novo Synthesis ◽  
Human Endothelial Cells ◽  
Tumor Promotor ◽  
Coagulation Assay ◽  
Platelet Aggregates ◽  
Umbilical Vein Endothelial Cells

SummaryHuman umbilical vein endothelial cells in culture synthesize thromboplastin upon stimulation with phytohaemagglutinin (PHA) or the tumor promotor 12-O-tetradecanoyl-phorbol-13-acetate (TPA). The thromboplastin activity is further strongly enhanced in a time dependent reaction by the presence of gel-filtered platelets or platelet aggregates. This effect was demonstrable at platelet concentrations lower than those normally found in plasma, it may thus be of pathophysiological relevance. The thromboplastin activity increased with increasing number of platelets added. Cycloheximide inhibited the increase, suggesting that de novo synthesis of the protein component of thromboplastin, apoprotein III, is necessary.When care was taken to remove monocytes no thromboplastin activity and no apoprotein HI antigen could be demonstrated in suspensions of gel-filtered platelets, platelets aggregated with thrombin or homogenized platelets when studied with a coagulation assay and an antibody neutralization technique.

DE NOVO SYNTHESIS OF STEROIDS BY THE TESTES OF THE HUMAN FOETUS AT MIDGESTATION

1971 ◽  
Vol 68 (1_Supplb) ◽  
pp. S135 ◽  
Author(s):  
R. S. Mathur ◽  
N. Wiqvist ◽  
E. Diczfalusy
Keyword(s):  
De Novo ◽  
De Novo Synthesis ◽  
Human Foetus
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