Mitotic Cycle Regulation in the Meristem of Cultured Roots: The Principal Control Point Hypothesis

1972 ◽  
pp. 15-32 ◽  
Author(s):  
J. Van’t Hof ◽  
C. J. Kovacs
Keyword(s):  
Mitotic Cycle ◽  
Control Point ◽  
Cycle Regulation

Calcium and cell cycle control

Development ◽  
1990 ◽  
Vol 108 (4) ◽  
pp. 525-542 ◽  
Author(s):  
M. Whitaker ◽  
R. Patel
Keyword(s):  
Cell Cycle ◽  
Sea Urchin ◽  
Mammalian Cells ◽  
Cell Cycle Regulation ◽  
Sea Urchins ◽  
Cell Cycle Control ◽  
Control Point ◽  
Control Cell ◽  
Free Calcium ◽  
Cycle Regulation

The cell division cycle of the early sea urchin embryo is basic. Nonetheless, it has control points in common with the yeast and mammalian cell cycles, at START, mitosis ENTRY and mitosis EXIT. Progression through each control point in sea urchins is triggered by transient increases in intracellular free calcium. The Cai transients control cell cycle progression by translational and post-translational regulation of the cell cycle control proteins pp34 and cyclin. The START Cai transient leads to phosphorylation of pp34 and cyclin synthesis. The mitosis ENTRY Cai transient triggers cyclin phosphorylation. The motosis EXIT transient causes destruction of phosphorylated cyclin. We compare cell cycle regulation by calcium in sea urchin embryos to cell cycle regulation in other eggs and oocytes and in mammalian cells.

scholarly journals Essential role of translation factor eIF5a in cytokine production and cell cycle regulation in primary CD8 T lymphocytes

2021 ◽  
Author(s):  
Thomas Ching-Jen Tan ◽  
Van Kelly ◽  
Xiaoyan Zou ◽  
Tony Ly ◽  
Rose Zamoyska
Keyword(s):  
Translational Control ◽  
Immune Cell ◽  
Control Point ◽  
Elongation Factor ◽  
Mrna Translation ◽  
Post Translational Modification ◽  
Translation Factors ◽  
Cycle Regulation ◽  
Multiple Immune Cell

Translational control adjusts protein production rapidly and facilitates local cellular responses to environmental conditions. Translation can be regulated through sequestration of mRNAs by regulatory proteins or RNAs, but also by the availability of ribosomes and translation factors which enable initiation and elongation of nascent polypeptides. Traditionally initiation of mRNA translation has been considered to be a major translational control point, however, control of peptide elongation can also play a role. Here we show that post-translational modification of the elongation factor, eIF5a, controls translation of subsets of proteins in naive T-cells upon activation. Sequencing of nascent polypeptides indicated that functional eIF5a was required for the production of proteins which regulate T-cell proliferation and effector function. Control of translation in multiple immune cell lineages is required to co-ordinate immune responses and these data illustrate that translational elongation can contribute to post-transcriptional regulons important for the control of inflammation.

scholarly journals Reprogramming the Cell Cycle for Endoreduplication in Rodent Trophoblast Cells

1998 ◽  
Vol 9 (4) ◽  
pp. 795-807 ◽  
Author(s):  
Alasdair MacAuley ◽  
James C. Cross ◽  
Zena Werb
Keyword(s):  
Cell Cycle ◽  
Cell Differentiation ◽  
Giant Cell ◽  
Mitotic Cycle ◽  
Mitotic Cell ◽  
Giant Cells ◽  
Cyclin B ◽  
Helix Loop Helix ◽  
Trophoblast Giant Cells ◽  
Cycle Regulation

Differentiation of trophoblast giant cells in the rodent placenta is accompanied by exit from the mitotic cell cycle and onset of endoreduplication. Commitment to giant cell differentiation is under developmental control, involving down-regulation of Id1and Id2, concomitant with up-regulation of the basic helix-loop-helix factor Hxt and acquisition of increased adhesiveness. Endoreduplication disrupts the alternation of DNA synthesis and mitosis that maintains euploid DNA content during proliferation. To determine how the mammalian endocycle is regulated, we examined the expression of the cyclins and cyclin-dependent kinases during the transition from replication to endoreduplication in the Rcho-1 rat choriocarcinoma cell line. We cultured these cells under conditions that gave relatively synchronous endoreduplication. This allowed us to study the events that occur during the transition from the mitotic cycle to the first endocycle. With giant cell differentiation, the cells switched cyclin D isoform expression from D3 to D1 and altered several checkpoint functions, acquiring a relative insensitivity to DNA-damaging agents and a coincident serum independence. The initiation of S phase during endocycles appeared to involve cycles of synthesis of cyclins E and A, and termination of S was associated with abrupt loss of cyclin A and E. Both cyclins were absent from gap phase cells, suggesting that their degradation may be necessary to allow reinitiation of the endocycle. The arrest of the mitotic cycle at the onset of endoreduplication was associated with a failure to assemble cyclin B/p34cdk1complexes during the first endocycle. In subsequent endocycles, cyclin B expression was suppressed. Together these data suggest several points at which cell cycle regulation could be targeted to shift cells from a mitotic to an endoreduplicative cycle.

The Improvement of Paclitaxel Cytotoxicity using Nanocellulose based Nature Resources

2019 ◽  
Vol 1 (1) ◽  
pp. 7
Author(s):  
R Nahrowi ◽  
A Setiawan ◽  
Noviany Noviany ◽  
I Sukmana ◽  
S D Yuwono
Keyword(s):  
Drug Delivery ◽  
Drug Release ◽  
Natural Resources ◽  
Cell Viability ◽  
Cancer Cells ◽  
Drug Delivery System ◽  
Target Cell ◽  
Mitotic Cycle ◽  
Potential Sources ◽  
Local Accumulation

Paclitaxel is one of the cancer drugs that often used. These drug kills cancer cells byinhibiting mitotic cycle. The efficiency of paclitaxel is increased by the use ofnanomaterials as a carrier of paclitaxel. Nanomaterials can enhance encapsulationefficiency, improve the drug release to the target cell following nanomaterialdegradation, and improve local accumulation of drug in the cell through endocytosisreceptor. Nanomaterial that often used forencapsulation of paclitaxel is a polymerderived from natural resources such as cellulose. The advantages of cellulose as acarrier of paclitaxel are nontoxic, biodegradable, and very abundant from varioussources. One of the potential sources of cellulose for drug delivery system is cassavabaggase.Keywords: Paclitaxel, encapsulation, cell viability, nanocellulose

The Influence of Process Openings on the Acoustic Efficiency of Gas Control Point Barriers

Vestnik MEI ◽  
2020 ◽  
Vol 3 (3) ◽  
pp. 48-54
Author(s):  
Svetlana A. Kuzminova ◽  
◽  
Vladimir B. Tupov ◽  
Keyword(s):  
Control Point ◽  
Gas Control

Roulette Wheel Selection based Heuristic Algorithm for the Orienteering Problem

2014 ◽  
Vol 13 (1) ◽  
pp. 4127-4145
Author(s):  
Madhushi Verma ◽  
Mukul Gupta ◽  
Bijeeta Pal ◽  
Prof. K. K. Shukla
Keyword(s):  
Triangle Inequality ◽  
Time Budget ◽  
Control Point ◽  
Hamiltonian Path ◽  
Real Life ◽  
Tourism Industry ◽  
Orienteering Problem ◽  
Complete Graphs ◽  
Roulette Wheel Selection ◽  
Roulette Wheel

Orienteering problem (OP) is an NP-Hard graph problem. The nodes of the graph are associated with scores or rewards and the edges with time delays. The goal is to obtain a Hamiltonian path connecting the two necessary check points, i.e. the source and the target along with a set of control points such that the total collected score is maximized within a specified time limit. OP finds application in several fields like logistics, transportation networks, tourism industry, etc. Most of the existing algorithms for OP can only be applied on complete graphs that satisfy the triangle inequality. Real-life scenario does not guarantee that there exists a direct link between all control point pairs or the triangle inequality is satisfied. To provide a more practical solution, we propose a stochastic greedy algorithm (RWS_OP) that uses the roulette wheel selectionmethod, does not require that the triangle inequality condition is satisfied and is capable of handling both complete as well as incomplete graphs. Based on several experiments on standard benchmark data we show that RWS_OP is faster, more efficient in terms of time budget utilization and achieves a better performance in terms of the total collected score ascompared to a recently reported algorithm for incomplete graphs.

EVALUASI KETELITIAN HORIZONTAL DARI CITRA TEGAK SATELIT RESOLUSI SANGAT TINGGI MENGGUNAKAN SRTM DAN TERRASAR-X UNTUK PEMETAAN SKALA BESAR

2018 ◽  
Vol 2 ◽  
pp. 535
Author(s):  
Maundri Prihanggo
Keyword(s):  
Control Point ◽  
Ground Control ◽  
Surface Model ◽  
Digital Surface Model ◽  
Check Point ◽  
Ground Control Point

<p>Saat ini, citra satelit resolusi sangat tinggi digunakan dalam berbagai macam aplikasi, terutama pemetaan skala besar. Sebelum dapat digunakan, citra satelit tersebut harus diorthorektifikasi terlebih dahulu. Data <em>Digital Surface Model </em>(DSM) dan <em>Ground Control Point</em> (GCP) adalah dua data utama yang diperlukan saat melakukan orthorektifikasi. Perbedaan data DSM yang digunakan akan menghasilkan perbedaan nilai ketelitian horizontal pada kedua citra tegak hasil orthorektifikasi. Pada penelitian ini digunakan dua jenis DSM yaitu SRTM dan Terrasar-X. Ketelitian vertikal dari SRTM adalah 90 m sedangkan ketelitian vertikal dari Terrasar-X adalah 12,5 m. Penelitian ini berlokasi di Wilayah Buli, Kabupaten Halmahera Timur, Provinsi Maluku. Terdapat tiga sensor citra satelit yang digunakan yaitu Pleiades, Quickbird dan Worldview-2 yang digunakan pada lokasi penelitian. Total GCP yang digunakan adalah 33 titik, tiap titiknya diukur dengan melakukan pengamatan geodetik dan memiliki ketelitian horizontal ≤15 cm dan ketelitian vertikal ≤30 cm. Ketelitian horizontal dari citra tegak satelit resolusi sangat tinggi diperoleh dengan melakukan uji terhadap Independent Check Point (ICP). Total ICP yang digunakan adalah 12 titik, tiap titik ICP diukur dengan metode dan standar yang sama dengan titik GCP. Ketelitian horizontal dengan Circular Error (CE 90) dari citra tegak satelit menggunakan data SRTM adalah 18,856 m sedangkan ketelitian horizontal dengan Circular Error (CE 90) dari citra tegak satelit menggunakan data Terrasar-X adalah 2.168 m . Hasil dari penelitian ini membuktikan bahwa ketelitian vertikal data DSM yang digunakan memberikan pengaruh pada citra tegak satelit hasil orthorektifikasi tersebut. Mengacu pada Peraturan Kepala BIG nomor 15 tahun 2014, citra tegak satelit hasil orthorektifikasi menggunakan data Terrasar-X sebagai DSM memenuhi ketelitian horizontal peta dasar kelas 3 skala 1:5.000 sedangkan citra tegak satelit hasil orthorektifikasi menggunakan data SRTM sebagai DSM tidak dapat memenuhi ketelitian horizontal peta dasar skala besar.</p><p><strong>Kata kunci:</strong> orthorektifikasi, DSM, ketelitian horizontal</p>

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