scholarly journals Light intensity and spectral composition drive reproductive success in the marine benthic diatom Seminavis robusta

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Gust Bilcke ◽  
Lore Van Craenenbroeck ◽  
Alexandre Castagna ◽  
Cristina Maria Osuna-Cruz ◽  
Klaas Vandepoele ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Light Intensity ◽  
Sexual Reproduction ◽  
Current Model ◽  
Incident Light ◽  
Flow Cytometric Analysis ◽  
Spectral Composition ◽  
Benthic Diatom ◽  
Cycle Phase ◽  
Light Intensities

AbstractThe properties of incident light play a crucial role in the mating process of diatoms, a group of ecologically important microalgae. While species-specific requirements for light intensity and photoperiod have been observed in several diatom species, little is known about the light spectrum that allows sexual reproduction. Here, we study the effects of spectral properties and light intensity on the initiation and progression of sexual reproduction in the model benthic diatom Seminavis robusta. We found that distinct stages of the mating process have different requirements for light. Vigorous mating pair formation occurred under a broad range of light intensities, ranging from 10 to 81 µE m−2 s−1, while gametogenesis and subsequent stages were strongly affected by moderate light intensities of 27 µE m−2 s−1 and up. In addition, light of blue or blue–green wavelengths was required for the formation of mating pairs. Combining flow cytometric analysis with expression profiling of the diatom-specific cyclin dsCyc2 suggests that progression through a blue light-dependent checkpoint in the G1 cell cycle phase is essential for induction of sexual reproduction. Taken together, we expand the current model of mating in benthic pennate diatoms, which relies on the interplay between light, cell cycle and sex pheromone signaling.

PCNA and total nuclear protein content as markers of cell proliferation in pea tissue

1992 ◽  
Vol 102 (1) ◽  
pp. 71-78 ◽  
Author(s):  
SANDRA CITTERIO ◽  
SERGIO SGORBATI ◽  
MARISA LEVI ◽  
BRUNO MARIA COLOMBO ◽  
ELIO SPARVOLI
Keyword(s):  
Cell Cycle ◽  
Cell Proliferation ◽  
Protein Content ◽  
Time Course ◽  
Nuclear Protein ◽  
Flow Cytometric Analysis ◽  
Nuclear Antigen ◽  
Cycle Phase ◽  
Proliferating Cells ◽  
Embryo Cells

The identification of cell proliferation markers has been shown to be a useful tool with which to study basic mechanisms of cell cycle progression. The use of immunofluorescence techniques revealed the presence of the proliferating cell nuclear antigen (PCNA) in pea tissue, where we observed a high PCNA expression in proliferating cells of the root meristem compared to noncycling cells of the differentiated leaf. The presence of PCNA was monitored also during the time-course of seed germination, before, during and after the cell cycle resumption of the embryo cells. PCNA is present in embryo cells not only during and after resumption of the cell cycle but also before, when cells have not yet begun replicating their genome. A bivariate flow cytometric analysis of DNA and nuclear protein content was used to localize precisely the cells of the examined pea tissues in different cell cycle phase subcompartments. A high correlation was found between the degree of cell proliferation and the protein content of G1 nuclei, on the one hand, and the percentage of PCNA positive cells on the other.

scholarly journals Light Exposure during Days with Night, Outdoor, and Indoor Work

2019 ◽  
Vol 63 (6) ◽  
pp. 651-665 ◽  
Author(s):  
Stine Daugaard ◽  
Jakob Markvart ◽  
Jens Peter Bonde ◽  
Jens Christoffersen ◽  
Anne Helene Garde ◽  
...  
Keyword(s):  
Light Intensity ◽  
Light Exposure ◽  
Spectral Composition ◽  
Working Hours ◽  
Well Being ◽  
Outdoor Workers ◽  
Light Levels ◽  
Light Intensities ◽  
Treatment Of Depression ◽  
Night Shifts

Abstract Objective To assess light exposure during days with indoor, outdoor, and night work and days off work. Methods Light intensity was continuously recorded for 7 days across the year among indoor (n = 170), outdoor (n = 151), and night workers (n = 188) in Denmark (55–56°N) equipped with a personal light recorder. White light intensity, duration above 80, 1000, and 2500 lux, and proportion of red, green, and blue light was depicted by time of the day and season for work days and days off work. Results Indoor workers’ average light exposure only intermittently exceeded 1000 lux during daytime working hours in summer and never in winter. During daytime working hours, most outdoor workers exceeded 2500 lux in summer and 1000 lux in winter. Night workers spent on average 10–50 min >80 lux when working night shifts. During days off work, indoor and night workers were exposed to higher light intensities than during work days and few differences were seen between indoor, outdoor, and night workers. The spectral composition of light was similar for indoor, outdoor, and night workers during days at and off work. Conclusion The night workers of this study were during night hours on average exposed for a limited time to light intensities expected to suppress melatonin. The indoor workers were exposed to light levels during daylight hours that may reduce general well-being and mood, especially in winter. Outdoor workers were during summer daylight hours exposed to light levels comparable to those used for the treatment of depression.

Depletion of the Shwachman-Diamond Syndrome Protein in Hematopoietic Progenitor Cells Impairs Growth, Colony Formation, and Ribosome Function.

Blood ◽  
2008 ◽  
Vol 112 (11) ◽  
pp. 2046-2046
Author(s):  
Gulay Sezgin ◽  
Abdallah Nihrane ◽  
Steven Ellis ◽  
Johnson M. Liu
Keyword(s):  
Cell Cycle ◽  
Fluorescent Protein ◽  
Bone Marrow Failure ◽  
Gradient Centrifugation ◽  
Flow Cytometric Analysis ◽  
Ribosomal Subunit ◽  
Autosomal Recessive Disorder ◽  
Cycle Phase ◽  
Cell Extracts ◽  
Shwachman Diamond Syndrome

Abstract Shwachman-Diamond syndrome (SDS) is an autosomal recessive disorder characterized by pancreatic exocrine dysfunction, skeletal abnormalities, and bone marrow failure, which can evolve to leukemia. Mutations in SBDS have been shown to cause SDS. We and other investigators have suggested that SBDS orthologs in yeast play a role in biogenesis and function of the 60S ribosomal subunit. To clarify the unknown function of SBDS in hematopoiesis, human erythroleukemia TF-1 cells were transduced with lentiviral vectors expressing the green fluorescent protein (GFP), neomycin phosphotransferase, and small interfering RNA (siRNA) against SBDS. After transduction, cells were selected for neomycin resistance and then sorted by flow cytometry. To probe for SBDS, an antibody against the carboxyl-terminus of human SBDS was generated, and individual TF-1 cell clones expressing different siRNAs were confirmed to knock down SBDS expression by Western blot analysis. Our experiments were aimed at analyzing the cellular effects of SBDS knockdown. The growth and hematopoietic colony forming potential of TF-1 knockdown cells were markedly hindered when compared to cells stably transduced with siRNA against a scrambled SBDS sequence. Using propidium iodide staining and flow cytometric analysis, we found an increased percentage of knockdown cells retained at the G0/G1 cell cycle phase. To address whether TF-1 cells expressing siRNA against SBDS have a selective deficiency of 60S ribosomal subunits, cell extracts were prepared and polysome profiles examined after sucrose gradient centrifugation. In preliminary experiments, TF-1 cells expressing siRNA against SBDS appeared to show a reduction in free 60S subunits and 80S subunits with a shift toward smaller polysomes, compared to cells expressing the scrambled sequence siRNA. We conclude that depletion of SBDS results in a significant growth and clonogenic defect in TF-1 hematopoietic cells. Our preliminary results also suggest defects in ribosome function and cell cycle transit, which may provide an integrated molecular explanation for the hematopoietic defect in SDS since nucleolar stress has been linked to cell cycle arrest and p53 stabilization.

Radiosensitive effect of gemcitabine on nasopharyngeal carcinoma CNE-1 cell line

2006 ◽  
Vol 24 (18_suppl) ◽  
pp. 20105-20105
Author(s):  
Y. Chen ◽  
X. Yu
Keyword(s):  
Cell Cycle ◽  
Nasopharyngeal Carcinoma ◽  
Cell Line ◽  
Carcinoma Cell ◽  
Clonogenic Assay ◽  
Flow Cytometric Analysis ◽  
Cell Cycle Phase ◽  
Cycle Phase ◽  
Flow Cytometric ◽  
Damage Repair

20105 Background: To observe the effect and mechanism of gemcitabine-induced radiosensitization on CNE-1 nasopharyngeal carcinoma cell line. Methods: The cell survival curves were obtained with clonogenic assay. The cell cycle phases were measured with flow cytometric analysis. Results: No cytotoxic effect was observed in 0.1 μM and 2 μM gemcitabine alone group. The radiosensitivities were observed in the groups treated with radiation and gemcitabine exposed in different consistencies and times. The SER were 1.35,1.82; 1.55 and 2.16 respectively. The G1 cell cycle phase block was observed in the two consistency groups after exposing to gemcitabine for 24 hours. Dq were rather lower in 2 μM groups especially that exposed for 24 hours. Conclusions: The radiosensitivity was obviously observed in the groups treated with two consistencies of gemcitabine. The effect was more obviously as the consistency and the exposing time increased. The block of cell cycle from G1 to S and the decrease of sublethal damage repair might be contributed to the mechanism. No significant financial relationships to disclose.

Cell cycle events in the green alga Chlamydomonas eugametos and their control by environmental factors

1992 ◽  
Vol 102 (3) ◽  
pp. 469-474
Author(s):  
V. ZACHLEDER ◽  
H. VAN DEN ENDE
Keyword(s):  
Cell Cycle ◽  
Light Intensity ◽  
Green Alga ◽  
External Energy ◽  
Endogenous Factors ◽  
Daughter Cells ◽  
Commitment Period ◽  
Light Intensities ◽  
Chlamydomonas Eugametos ◽  
Sufficient Energy

A procedure for routine synchronization of large amounts of the unicellular green alga Chlamydomonas eugametos in liquid culture by alternating light and dark periods is described. The synchronized populations were grown at various light intensities and temperatures. The effect of these variables on the lengths of parts of the cell cycle and the number of daughter cells per cell division was followed. The cell cycle of C. eugametos started with a period in which the cells increased in size only (precommitment period). The length of this period was dependent on both the light intensity and the temperature. At the end of this period, a key point of the cell cycle (called commitment point) was attained. From this point, the cell were committed to divide and cell reproduction was triggered. The following period (post-commitment period), during which daughter cells were formed, could be traversed without supply of external energy, and without further growth of the cells. However, if sufficient energy was supplied during this period, the cells were able to attain more commitment points, leading to a higher number of daughter cells. The postcommitment period was fairly constant within a certain range of light intensity. At light intensities leading to more commitment points, however, this period was prolonged. No evidence was found for circadian rhythms or endogenous factors of “Zeitgeber” type playing a role in the control of growth and reproductive sequences in the cell cycle of C. eugametos.

scholarly journals Characterization of Growth and Cell Cycle Events Affected by Light Intensity in the Green Alga Parachlorella kessleri: A New Model for Cell Cycle Research

Biomolecules ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 891
Author(s):  
Vilém Zachleder ◽  
Ivan N. Ivanov ◽  
Veronika Kselíková ◽  
Vitali Bialevich ◽  
Milada Vítová ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Dna Replication ◽  
Light Intensity ◽  
Green Alga ◽  
Neutral Lipids ◽  
Growth Parameters ◽  
Daughter Cells ◽  
Light Intensities ◽  
Multiple Fission ◽  
Parachlorella Kessleri

Multiple fission is a cell cycle variation leading to the production of more than two daughter cells. Here, we used synchronized cultures of the chlorococcal green alga Parachlorella kessleri to study its growth and pattern of cell division under varying light intensities. The time courses of DNA replication, nuclear and cellular division, cell size, total RNA, protein content, dry matter and accumulation of starch were observed at incident light intensities of 110, 250 and 500 µmol photons m−2s−1. Furthermore, we studied the effect of deuterated water on Parachlorella kessleri growth and division, to mimic the effect of stress. We describe a novel multiple fission cell cycle pattern characterized by multiple rounds of DNA replication leading to cell polyploidization. Once completed, multiple nuclear divisions were performed with each of them, immediately followed by protoplast fission, terminated by the formation of daughter cells. The multiple fission cell cycle was represented by several consecutive doublings of growth parameters, each leading to the start of a reproductive sequence. The number of growth doublings increased with increasing light intensity and led to division into more daughter cells. This study establishes the baseline for cell cycle research at the molecular level as well as for potential biotechnological applications, particularly directed synthesis of (deuterated) starch and/or neutral lipids as carbon and energy reserves.

scholarly journals Light Environment in Tropical Rain Forest of Central Amazonia

1971 ◽  
Vol 1 (2) ◽  
pp. 37-49 ◽  
Author(s):  
W. L. F. Brinkmann
Keyword(s):  
Light Intensity ◽  
Rain Forest ◽  
Relative Frequency ◽  
Spectral Composition ◽  
Terra Firme ◽  
Strong Shift ◽  
Riverine Forest ◽  
Light Intensities ◽  
Rain Season ◽  
Central Amazonia

Abstract Light intensity above the groundstoreys (120 cm) and inbetween the ground strata of a Riverine forest, a Carrasco forest and a terra firme Rain forest was recorded through two day periods of time in the rain season (April/May) and the dry season (August) of 1969. Measurements were undertaken between 6 a.m. and 18 p.m. in minute by minute intervals (51.840 readings). The relative frequency of light intensity was computed for seven intensity classes and three periods of time per day. The spectral composition of light was determined as relative frequency of light intensities for five filter ranges of wavelengths, seven intensity classes and three periods of time per day. The riverine forest (best light conditions for the undertorey plant communities) and the terra firme Rain forest (worst conditions) developed extremely oposite positions with respect to forest light climate, while the Carrasco forest showed up with a somewhat intermediate character, but with a strong shift to terra firme Rain forest conditions. The spectral composition of light received by the ground strata of all three forest stands was as follows: 1) light intensities peaked in the RG 630 filter range of wavelenths (5.920 Ǻ — 7.500 Ǻ), 2) a secondary intensity peak covered the VG 9 filter (4.420 Ǻ — 6.440 Ǻ) and 3) a less important secondary peak matched the BG 12 filter band (3.500 Ǻ — 5.150 Ǻ). Inbetween the understorey communities, spectral light intensities were pretty low and showed another considerable red-shift.

Insights into Nano-Photo-Thermal Therapy of Cancer: The Kinetics of Cell Death and Effect on Cell Cycle

2020 ◽  
Vol 20 (5) ◽  
pp. 612-621
Author(s):  
Mousa Tabei ◽  
Elham Zeinizade ◽  
Jaber Beik ◽  
S. Kamran Kamrava ◽  
Zahra Nasiri ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Cell Death ◽  
Cancer Cells ◽  
Signaling Pathway ◽  
Flow Cytometric Analysis ◽  
Thermal Therapy ◽  
Normal Fibroblast ◽  
Cycle Phase ◽  
Flow Cytometric ◽  
Kinetics Of

Background: Despite considerable advances in nano-photo-thermal therapy (NPTT), there have been a few studies reporting in-depth kinetics of cell death triggered by such a new modality of cancer treatment. Objective: In this study, we aimed to (1) investigate the cell death pathways regulating the apoptotic responses to NPTT; and (2) ascertain the effect of NPTT on cell cycle progression. Methods: Folate conjugated gold nanoparticle (F-AuNP) was firstly synthesized, characterized and then assessed to determine its potentials in targeted NPTT. The experiments were conducted on KB nasopharyngeal cancer cells overexpressing folate receptors (FRs), as the model, and L929 normal fibroblast cells with a low level of FRs, as the control. Cytotoxicity was evaluated by MTT assay and the cell death mode (i.e., necrosis or apoptosis) was determined through AnnexinV/FITC-propidium iodide staining. Next, the gene expression profiles of some key apoptotic factors involved in the mitochondrial signaling pathway were investigated using RT-qPCR. Finally, cell cycle phase distribution was investigated at different time points post NPTT using flow cytometric analysis. Results: The obtained results showed that KB cell death following targeted NPTT was greater than that observed for L929 cells. The majority of KB cell death following NPTT was related to apoptosis. RT-qPCR analysis indicated that the elevated expression of Bax along with the depressed expression of Bcl-xL, Survivin and XIAP may involve in the regulation of apoptosis in response to NPTT. Flow cytometric analysis manifested that 16-24 hours after NPTT, the major proportion of KB cells was in the most radiosensitive phases of the cell cycle (G2/M). Conclusion: This study extended the understanding of the signaling pathway involved in the apoptotic response to NPTT. Moreover, the potential effect of NPTT on sensitizing cancer cells to subsequent radiation therapy was highlighted.

scholarly journals Flow cytometric analysis of the cell cycle phase specificity of DNA damage induced by radiation, hydrogen peroxide and doxorubicin

2002 ◽  
Vol 23 (3) ◽  
pp. 389-401 ◽  
Author(s):  
Alan J. Potter ◽  
Katherine A. Gollahon ◽  
Ben J.A. Palanca ◽  
Mary J. Harbert ◽  
Young M. Choi ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Hydrogen Peroxide ◽  
Dna Damage ◽  
Flow Cytometric Analysis ◽  
Cell Cycle Phase ◽  
Cycle Phase ◽  
Flow Cytometric

Quantification of the c-myc oncoprotein in human glioblastoma cells and tumor tissue

1989 ◽  
Vol 71 (2) ◽  
pp. 224-232 ◽  
Author(s):  
Herbert H. Engelhard ◽  
Albert B. Butler ◽  
Kenneth D. Bauer
Keyword(s):  
Cell Cycle ◽  
Flow Cytometry ◽  
Glial Cells ◽  
Tumor Tissue ◽  
Cultured Cells ◽  
Flow Cytometric Analysis ◽  
Immunoblot Analysis ◽  
Cycle Phase ◽  
Content Type ◽  
Fine Print

✓ The identification of a quantifiable oncoprotein marker in glial cells could lead to its use as an aid in the diagnosis, grading, and treatment of tumors of glial origin. In this study, monoclonal antibodies to the c-myc oncoprotein were used in conjunction with immunofluorescence microscopy, flow cytometry, and immunoblot analysis to quantitate and characterize the expression of this oncoprotein in neoplastic and benign cultured glial cells and brain-tumor tissue. Flow cytometric analysis revealed that the c-myc oncoprotein was highly expressed in neoplastic cell lines and in glioblastoma tumor specimens. In contrast, anti-c-myc oncoprotein staining was not present in a non-neoplastic glial cell line or in a benign brain tissue specimen. Immunoblot analysis revealed two distinct c-myc oncoprotein bands, having molecular weights of 64 and 75 kD. Densitometric determinations of the relative levels of the 64-kD protein were in good agreement with the determinations made by flow cytometry. Flow cytometry was also used to relate the quantity of the c-myc oncoprotein present in the cells to their cell cycle phase. In the malignant cultured cells, the protein underwent an approximate twofold increase as the cells progressed from G1/G0 to G2/M in the cell cycle. The present results suggest that the c-myc oncoprotein may prove to be a useful marker for the proliferative status and/or malignancy of glial cells.

Sign in / Sign up

Export Citation Format

Share Document