Contributions to the mechanisms of mitosis and roles of cytoplasmic microtubules from ultrastructural analyses of fungi

1978 ◽  
Vol 36 (2) ◽  
pp. 266-267
Author(s):  
I. Brent Heath
Keyword(s):  
Nuclear Envelope ◽  
Direct Application ◽  
Ultrastructural Analysis ◽  
General Interest ◽  
Research Results ◽  
Organelle Motility ◽  
Cytoplasmic Microtubules

Detailed ultrastructural analysis of fungal mitotic systems and cytoplasmic microtubules might be expected to contribute to a number of areas of general interest in addition to the direct application to the organisms of study. These areas include possibly fundamental general mechanisms of mitosis; evolution of mitosis; phylogeny of organisms; mechanisms of organelle motility and positioning; characterization of cellular aspects of microtubule properties and polymerization control features. This communication is intended to outline our current research results relating to selected parts of the above questions.Mitosis in the oomycetes Saprolegnia and Thraustotheca has been described previously. These papers described simple kinetochores and showed that the kineto- chores could probably be used as markers for the poorly defined chromosomes. Kineto- chore counts from serially sectioned prophase mitotic nuclei show that kinetochore replication precedes centriole replication to yield a single hemispherical array containing approximately the 4 n number of kinetochore microtubules diverging from the centriole associated "pocket" region of the nuclear envelope (Fig. 1).

Characterization of infrared materials EU 1269-Belgium: research results of the first year

1996 ◽  
Author(s):  
Piet Union ◽  
Peter F. Muys ◽  
Dirk Vyncke ◽  
Ben Depuydt ◽  
Pierre M. Boone
Keyword(s):  
First Year ◽  
Research Results ◽  
Infrared Materials

scholarly journals Novel Mega Best-Seller Karya Luluk HF Mariposa dalam Kajian Resepsi Sastra

2021 ◽  
Vol 19 (2) ◽  
pp. 152
Author(s):  
Tania Intan ◽  
Muhamad Adji
Keyword(s):  
Aggressive Behavior ◽  
Research Data ◽  
The Novel ◽  
Research Results ◽  
Female Protagonist ◽  
Data Source ◽  
The Difference ◽  
Horizon Of Expectations ◽  
The Way

This study discusses the reception of readers of the mega best-seller novel entitled Mariposa by Luluk HF. The purpose of this study is to (1) describe the reader's responses, (2) describe the horizon of readers' expectations, and (3) describe the factors that cause differences in responses and the horizon of expectations of readers of Mariposa's novel. The method applied is descriptive qualitative. This study uses a reception aesthetic approach that seeks to find consistent reception patterns as a reflection of the way the reader responds to the text. The research data consisted of texts containing the responses of twenty respondents from the data source in the form of the Goodreads reader site. The research results obtained are as follows. First, not all readers respond positively to the intrinsic elements of the novel, especially the characterization of the female protagonist who is considered to show aggressive behavior with a love motive. Second, most of the horizons of readers' expectations do not match the reality in Mariposa. Readings are generally motivated by curiosity because of the hyperbolic labeling of the novel, recommendations from friends, and the discourse of filming the novel. Third, the factors that cause the difference or suitability of the horizon of readers' expectations for the Mariposa novel are knowledge of literature, knowledge of life, and experience of reading literary works.

scholarly journals The Investigating the red phenol absorption by multi-walled carbon nanotubes

2020 ◽  
Vol 4 (1) ◽  
pp. First
Author(s):  
Huynh Anh Hoang ◽  
Huynh Quyen
Keyword(s):  
Carbon Nanotubes ◽  
Langmuir Isotherm ◽  
Full Potential ◽  
Liquefied Petroleum Gas ◽  
Research Results ◽  
Cvd Method ◽  
Multi Walled Carbon Nanotubes ◽  
Hydrocarbon Gas ◽  
Walled Carbon Nanotubes

Since the end of the 20th century, nanomaterials such as carbon nanotubes (CNTs) have been considered as one of the greatest achievements in the field of material science. Nowadays, further research on CNTs is still being conducted to unfold the full potential of this material. Generally, CNTs production methods have been extensively studied, specifically on CNTs synthesis route via liquefied hydrocarbon gas in the presence of a catalyst. From the synthesized material, further investigation including characterization and investigation of this nano size system’s effects on the physics, chemical, mechanical rules applied to macroscopic (bulk materials) and microscopic systems (atoms, molecules). In this present work, we demonstrated the research results of the synthesis of nano-carbon materials from a liquefied hydrocarbon gas (Liquefied Petroleum Gas: LPG) and its application to red phenol absorption in the liquid phase. CNTs used in this study were synthesized by chemical vapor deposition (CVD) method with Fe /ℽ-Al2O3 as the catalyst. The research results demonstrated that CNTs synthesized from LPG in this work were reported to be multi-walled tubes (MWCNTs: Multi-Walled Carbon Nanotubes) with physical characteristics including average internal and external diameters were of 6 nm and 17 nm, respectively. The measured specific surface suggested by BET data was 200 m2/g. The experimental study of red phenol adsorption by MWCNTs showed that the adsorption process followed both Freundlich and Langmuir isotherm adsorption models with the maximum monolayer adsorption capacity of 47.2 mg/g. The research results again showed that it was possible to synthesize MWCNTs from hydrocarbon gas sources via the CVD method by utilizing catalysts. Additionally, red phenol absorption via such material had shown to follow both Freundlich and Langmuir isotherm model, which allow further characterization of this material using Raman, EDX, SEM, TEM, BET, in order to extend the library database on the characterization of the reported synthesized material.

Novel biochemical and functional insights into nuclear Ca2+ transport through IP3Rs and RyRs in osteoblasts

2000 ◽  
Vol 278 (5) ◽  
pp. F784-F791 ◽  
Author(s):  
Olugbenga A. Adebanjo ◽  
Gopa Biswas ◽  
Baljit S. Moonga ◽  
Hindupur K. Anandatheerthavarada ◽  
Li Sun ◽  
...  
Keyword(s):  
Gene Expression ◽  
Nuclear Envelope ◽  
Nuclear Membrane ◽  
Ryanodine Receptors ◽  
Functional Characterization ◽  
Inositol Trisphosphate Receptors ◽  
Nuclear Membranes ◽  
Sds Page ◽  
Direct Regulation

We report the first biochemical and functional characterization of inositol trisphosphate receptors (IP3Rs) and ryanodine receptors (RyRs) in the nuclear membrane of bone-forming (MC3T3-E1) osteoblasts. Intact nuclei fluoresced intensely with anti-RyR (Ab34) and anti-IP3R (Ab40) antisera in a typically peripheral nuclear membrane pattern. Isolated nuclear membranes were next subjected to SDS-PAGE and blotted with isoform-specific anti-receptor antisera, notably Ab40, anti-RyR-1, anti-RyR-2 (Ab129), and anti-RyR-3 (Ab180). Only anti-RyR-1 and Ab40 showed bands corresponding, respectively, to full-length RyR-1 (∼500 kDa) and IP3R-1 (∼250 kDa). Band intensity was reduced by just ∼20% after brief tryptic proteolysis of intact nuclei; this confirmed that isolated nuclear membranes were mostly free of endoplasmic reticular contaminants. Finally, the nucleoplasmic Ca2+ concentration ([Ca2+]np) was measured in single nuclei by using fura-dextran. The nuclear envelope was initially loaded with Ca2+ via Ca2+-ATPase activation (1 mM ATP and ∼100 nM Ca2+). Adequate Ca2+ loading was next confirmed by imaging the nuclear envelope (and nucleoplasm). Exposure of Ca2+-loaded nuclei to IP3 or cADP ribose resulted in a rapid and sustained [Ca2+]np elevation. Taken together, the results provide complementary evidence for nucleoplasmic Ca2+ influx in osteoblasts through nuclear membrane-resident IP3Rs and RyRs. Our findings may conceivably explain the direct regulation of osteoblastic gene expression by hormones that use the IP3-Ca2+pathway.

The Steady-State and Decay Characteristics of Protein Tryptophan Fluorescence from Algae

1988 ◽  
Vol 42 (8) ◽  
pp. 1405-1412 ◽  
Author(s):  
M. Baek ◽  
W. H. Nelson ◽  
P. E. Hargraves ◽  
J. F. Tanguay ◽  
S. L. Suib
Keyword(s):  
Steady State ◽  
Tryptophan Fluorescence ◽  
Fluorescence Decay ◽  
Direct Application ◽  
Fluorescence Lifetimes ◽  
Bacterial Protein ◽  
Steady State Fluorescence ◽  
Tryptophan Residues ◽  
Rapid Characterization

The intrinsic steady-state fluorescence due to tryptophan has been obtained from monospecific cultures of fourteen plankton algae of various genera. Fluorescence decay profiles of protein tryptophan residues were obtained for eight marine plankton algae. Each organism exhibits a strong maximum in its emission spectrum at 320–340 nm when excited at 290 nm. Iodide quenching and denaturization experiments with 8 M urea provide strong evidence for the assignment of the 320–340 nm fluorescence to protein tryptophan. Most importantly, the decay of this bacterial protein tryptophan fluorescence has been described. The observation that characteristic protein-tryptophan fluorescence lifetimes have been obtained for each organism suggests that measurements of fluorescence lifetimes may be helpful in the rapid characterization of algae. Direct application will likely be found in combination with the measurement of other luminescence parameters.

scholarly journals Characterization of SUN-domain proteins at the higher plant nuclear envelope

2010 ◽  
Vol 61 (1) ◽  
pp. 134-144 ◽  
Author(s):  
Katja Graumann ◽  
John Runions ◽  
David E. Evans
Keyword(s):  
Nuclear Envelope ◽  
Higher Plant ◽  
Sun Domain

scholarly journals Microtubule dynamics at the G2/M transition: abrupt breakdown of cytoplasmic microtubules at nuclear envelope breakdown and implications for spindle morphogenesis.

1996 ◽  
Vol 135 (1) ◽  
pp. 201-214 ◽  
Author(s):  
Y Zhai ◽  
P J Kronebusch ◽  
P M Simon ◽  
G G Borisy
Keyword(s):  
Nuclear Envelope ◽  
Fluorescence Ratio ◽  
Subsequent Increase ◽  
Abrupt Decrease ◽  
Nuclear Envelope Breakdown ◽  
Anaphase Onset ◽  
Chromosome Attachment ◽  
Direct Fluorescence ◽  
Cytoplasmic Microtubules ◽  
Tubulin Immunofluorescence

We recently developed a direct fluorescence ratio assay (Zhai, Y., and G.G. Borisy. 1994. J. Cell Sci. 107:881-890) to quantify microtubule (MT) polymer in order to determine if net MT depolymerization occurred upon anaphase onset as the spindle was disassembled. Our results showed no net decrease in polymer, indicating that the disassembly of kinetochore MTs was balanced by assembly of midbody and astral MTs. Thus, the mitosis-interphase transition occurs by a redistribution of tubulin among different classes of MTs at essentially constant polymer level. We now examine the reverse process, the interphase-mitosis transition. Specifically, we quantitated both the level of MT polymer and the dynamics of MTs during the G2/M transition using the fluorescence ratio assay and a fluorescence photoactivation approach, respectively. Prophase cells before nuclear envelope breakdown (NEB) had high levels of MT polymer (62%) similar to that previously reported for random interphase populations (68%). However, prophase cells just after NEB had significantly reduced levels (23%) which recovered as MT attachments to chromosomes were made (prometaphase, 47%; metaphase, 56%). The abrupt reorganization of MTs at NEB was corroborated by anti-tubulin immunofluorescence staining using a variety of fixation protocols. Sensitivity to nocodazole also increased at NEB. Photoactivation analyses of MT dynamics showed a similar abrupt change at NEB, basal rates of MT turnover (pre-NEB) increased post-NEB and then became slower later in mitosis. Our results indicate that the interphase-mitosis (G2/M) transition of the MT array does not occur by a simple redistribution of tubulin at constant polymer level as the mitosis-interphase (M/G1) transition. Rather, an abrupt decrease in MT polymer level and increase in MT dynamics occurs tightly correlated with NEB. A subsequent increase in MT polymer level and decrease in MT dynamics occurs correlated with chromosome attachment. These results carry implications for understanding spindle morphogenesis. They indicate that changes in MT dynamics may cause the steady-state MT polymer level in mitotic cells to be lower than in interphase. We propose that tension exerted on the kMTs may lead to their lengthening and thereby lead to an increase in the MT polymer level as chromosomes attach to the spindle.

Characterization of electrical steel grades for direct application to electrical machine design tools

2008 ◽  
Vol 320 (20) ◽  
pp. 2538-2541 ◽  
Author(s):  
Waqas M. Arshad ◽  
Thomas Ryckebush ◽  
Arvid Broddefalk ◽  
Freddy Magnussen ◽  
Heinz Lendenmann ◽  
...  
Keyword(s):  
Electrical Steel ◽  
Direct Application ◽  
Machine Design ◽  
Electrical Machine ◽  
Design Tools ◽  
Steel Grades

scholarly journals A role for Rab5 in structuring the endoplasmic reticulum

2007 ◽  
Vol 178 (1) ◽  
pp. 43-56 ◽  
Author(s):  
Anjon Audhya ◽  
Arshad Desai ◽  
Karen Oegema
Keyword(s):  
Endoplasmic Reticulum ◽  
Caenorhabditis Elegans ◽  
Nuclear Envelope ◽  
Rab Gtpases ◽  
C Elegans ◽  
Rab Family ◽  
Kinetics Of

The endoplasmic reticulum (ER) is a contiguous network of interconnected membrane sheets and tubules. The ER is differentiated into distinct domains, including the peripheral ER and nuclear envelope. Inhibition of two ER proteins, Rtn4a and DP1/NogoA, was previously shown to inhibit the formation of ER tubules in vitro. We show that the formation of ER tubules in vitro also requires a Rab family GTPase. Characterization of the 29 Caenorhabditis elegans Rab GTPases reveals that depletion of RAB-5 phenocopies the defects in peripheral ER structure that result from depletion of RET-1 and YOP-1, the C. elegans homologues of Rtn4a and DP1/NogoA. Perturbation of endocytosis by other means did not affect ER structure; the role of RAB-5 in ER morphology is thus independent of its well-studied requirement for endocytosis. RAB-5 and YOP-1/RET-1 also control the kinetics of nuclear envelope disassembly, which suggests an important role for the morphology of the peripheral ER in this process.

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