The effect of ultraviolet radiation on early stages of activation of human lymphocytes: inhibition is independent of effects on DNA

1982 ◽  
Vol 60 (9) ◽  
pp. 854-860 ◽  
Author(s):  
Gustavo Castellanos ◽  
Trevor Owens ◽  
Christopher Rudd ◽  
Trevor Bladon ◽  
George Setterfield ◽  
...  
Keyword(s):  
Ultraviolet Radiation ◽  
Human Lymphocytes ◽  
Inhibitory Effect ◽  
Activation Process ◽  
Cell Periphery ◽  
Resting Cells ◽  
Con A ◽  
Pump Function ◽  
Cation Pump

Low doses (30–84 ergs/mm2, 1 erg = 107 J) of ultraviolet radiation (UV) caused severe inhibition of the proliferation of human lymphocytes in vitro. Greatest inhibition was produced when resting cells were irradiated immediately prior to stimulation with concanavalin A (Con A); this was true whether activation was measured by the incorporation of labelled leucine, uridine, or thymidine. If UV was applied at 44 h after culture in presence of Con A, the incorporation of [3H]thymidine measured 4 h later was seen to be inhibited but transcription and translation were scarcely affected. UV, applied after the appearance of the Con A induced thymidine transport system, did not inhibit its function. The disaggregation of chromatin and increase in nuclear volume characteristic of, and essential to, the proliferative response of lymphocytes were completely inhibited if the cells were irradiated before mitogen was added to the cultures, but were unaffected if irradiation occurred after 16 h of culture in presence of Con A. Cells irradiated with 84 ergs/mm2 at the onset of culture with mitogen did not show the early increase of cation pump function which is a characteristic of stimulated lymphocytes, when this was measured by means of 86Rb uptake after 2–4 h culture. The mitogen-stimulated activation of cation pump function has previously been shown to be unaffected by concentrations of cycloheximide and actinomycin D which produce virtually complete inhibition of protein and RNA synthesis, respectively. The major inhibitory effect of UV treatment of lymphocytes at onset of culture with Con A is therefore not on DNA or on DNA synthesis, but on some component(s) of the early activation process, possibly at the cell periphery; inactivation of this component prevents cells from proceeding into later stages of the proliferative pathway.

Effects of Ginsenoside Rg1 of Panax Ginseng on Mitosis in Human Blood Lymphocytes in Vitro

1980 ◽  
Vol 08 (03) ◽  
pp. 254-267 ◽  
Author(s):  
Lan-sang Tong ◽  
Chuan-ying Chao
Keyword(s):  
Dna Synthesis ◽  
Panax Ginseng ◽  
Human Lymphocytes ◽  
Resting Cells ◽  
Ginsenoside Rg1 ◽  
Con A ◽  
Pharmacological Significance ◽  
Treated Culture ◽  
Mitogenic Lectin

The ginsenoside Rg1 extracted from the root of Panax ginseng can promote mitosis in cultured human lymphocytes activated by PHA or Con A. Its most effective concentrations are around 0.0003-0.0005 mg per ml of medium. Experiments shows that its does not arrest the cells at any particular mitotic stage. It can also enhance the DNA synthesis in the activated lymphocytes. As a result of the increased number of mitotic cells and enhanced DNA synthesis, the cell density is significantly increased in the Rg1-treated culture as compared with the control. However, in the absence of a mitogenic lectin, Rg1 cannot restart the quinescent human lymphocytes to divide in vitro; therefore it is not mitogenic to resting cells. The possible action Rg1 on activated human lymphocytes as well as its pharmacological significance are discussed.

scholarly journals Alloxan cytotoxicity in vitro. Inhibition of rubidium ion pumping in pancreatic β-cells

1977 ◽  
Vol 162 (1) ◽  
pp. 9-18 ◽  
Author(s):  
L Å Idahl ◽  
Å Lernmark ◽  
J Sehlin ◽  
I B Täljedal
Keyword(s):  
Plasma Membranes ◽  
Islet Cells ◽  
Protective Action ◽  
Inhibitory Effect ◽  
Dependent Manner ◽  
Nitrophenyl Phosphate ◽  
Cation Pump ◽  
Ion Pumping ◽  
Hydrolysis Of

Exposing micro-dissected pancreatic islets of non-inbred ob/ob mice to 2-5 mM-alloxan for 10 min decreased the ability of the islets to accumulate Rb+. Rb+ accumulation in pieces of exocrine pancreas was unaffected by alloxan. When islets were treated with alloxan in the presence of 2-20 mM-D-glucose, the Rb+-accumulating ability was protected in a dose-dependent manner. The protective action of D-glucose was reproduced with 3-O-methyl-D-glucose but not with L-glucose or D-mannoheptulose; mannoheptulose prevented D-glucose from exerting its protective action. The inhibition of Rb+ accumulation was due to a decreased inward pumping, since alloxan did not affect Rb+ efflux from pre-loaded islets. The inhibitory effect of alloxan had a latency of about 1 min, as revealed by experiments with dispersed islet cells in suspension. Alloxan-treated islets showed only a marginal decrease in ATP and no change in glucose 6-phosphate concentration. Although alloxan slightly decreased the hydrolysis of ATP in a subcellular fraction enriched in plasma membranes, this effect could not be attributed to a ouabain-sensitive adenosine triphosphatase. The plasma membranes exhibited a K+-activated hydrolysis of p-nitrophenyl phosphate; this enzyme activity too was insensitive to alloxan. Glucose may protect the univalent-cation pump by preventing permeation of alloxan via a path coupled to the hexose-transport system. Inhibition of the pump may be fundamental to the induction of alloxan-diabetes.

scholarly journals spe-43 is required for sperm activation in C. elegans

2017 ◽  
Author(s):  
Amber R. Krauchunas ◽  
Ernesto Mendez ◽  
Julie Zhouli Ni ◽  
Marina Druzhinina ◽  
Amanda Mulia ◽  
...  
Keyword(s):  
Transmembrane Protein ◽  
Activation Process ◽  
Deletion Mapping ◽  
Cell Periphery ◽  
Wild Type ◽  
Sperm Activation ◽  
C Elegans ◽  
Phenotypic And Genetic Characterization

ABSTRACTSuccessful fertilization requires that sperm are activated prior to contacting an oocyte. In C. elegans, this activation process, called spermiogenesis, transforms round immobile spermatids into motile, fertilization-competent spermatozoa. We describe the phenotypic and genetic characterization of spe-43, a new component of the spe-8 pathway, which is required for spermiogenesis in hermaphrodites; spe-43 hermaphrodites are self-sterile, while spe-43 males show wild-type fertility. When exposed to Pronase to activate sperm in vitro, spe-43 spermatids form long rigid spikes radiating outward from the cell periphery instead of forming a motile pseudopod, indicating that spermiogenesis initiates but is not completed. Using a combination of recombinant and deletion mapping and whole genome sequencing, we identified F09E8.1 as spe-43. SPE-43 is predicted to exist in two isoforms; one isoform appears to be a single-pass transmembrane protein while the other is predicted to be a secreted protein. SPE-43 can bind to other known sperm proteins, including SPE-4 and SPE-29, which are known to impact spermiogenesis. In summary, we have identified a membrane protein that is present in C. elegans sperm and is required for sperm activation via the hermaphrodite activation signal.

scholarly journals Clastogenic Effect of Atranorin, Evernic acid, and Usnic Acid on Human Lymphocytes

2014 ◽  
Vol 9 (4) ◽  
pp. 1934578X1400900 ◽  
Author(s):  
Gordana S. Stojanović ◽  
Miroslava Stanković ◽  
Igor Ž. Stojanović ◽  
Ivan Palić ◽  
Vesna Milovanović ◽  
...  
Keyword(s):  
Human Lymphocytes ◽  
Usnic Acid ◽  
Inhibitory Effect ◽  
Positive Control ◽  
Proliferation Index ◽  
Culture Solution ◽  
Antiproliferative Effects ◽  
Clastogenic Effect ◽  
And Control

Three lichen secondary metabolites atranorin (1), evernic acid (2), and usnic acid (3), were evaluated for their in vitro clastogenic and antiproliferative effects on human lymphocytes using the cytochalasin-B blocked micronucleus (CBMN) assay at concentrations of 2 μg/mL, 4 μg/mL and 6 μg/mL of final culture solution. The frequency of micronucleus (MN) was scored in binucleated cells, and cytokinesis-block proliferation index (CBPI) was calculated. Among the tested compounds, 3 exhibited the most prominent effect decreasing the frequency of MN in the range of 42.5% - 48.9%, that is about double of the positive control amifostin WR-2721 that reduces MN frequency for 22.0%. The effect of evernic acid was approximately equal to action of amifostin (23.2% −32.9%). Atranorin at concentrations of 2 μg/mL and 4 μg/mL decreasing the frequency of MN only for 11.1% and 1.8%, while in concentration of 6 μg/mL increases the frequency of MN for 9.6 %. The comparable CBPI values of the investigated compounds and control suggested that they did not show a statistically significant inhibitory effect on lymphocyte cell proliferation at applied concentrations.

Inversion in Volvox tertius: the effects of con A

1981 ◽  
Vol 48 (1) ◽  
pp. 355-366
Author(s):  
G.W. Ireland ◽  
S.E. Hawkins
Keyword(s):  
Cell Division ◽  
Cell Shape ◽  
Shape Change ◽  
Fluorescein Isothiocyanate ◽  
Inhibitory Effect ◽  
Con A ◽  
Cell Shape Change ◽  
Enhanced Production ◽  
Inside Out

During the development of Volvox tertius spheroids, a single-celled gonidium enlarges and undergoes multiple incomplete cleavages to give an embryo which is ‘inside-out’ with respect to the adult organism. A morphogenetic movement, termed ‘inversion’, turns this hollow ball of cells ‘inside-out’ through a hole, the phialopore. In V. tertius this phialopore possesses 4 inwardly directed lips. Normal inversion was studied in vitro in slide chambers and involved cell-shape changes accompanied by the production of pseudopodia and the bending backwards of the phialopore lips. 100 micrograms/ml Con A specifically and reversibly blocked inversion. Despite the inhibitory effect on cell division, the blocking of inversion was not due to the blocking of the last cell division some 50–100 min prior to inversion. Neither did the first cell-shape change from pear- to spindle-shape appear blocked. A feature of inhibition by Con A was the enhanced production of pseudopodia by embryos blocked at inversion, and the abnormal production of pseudopodia by embryos blocked at earlier stages. Non-inverting embryos showed internal flagella. We suggest that the Con A block to inversion, which may be reversed by alpha-methyl mannoside, arises from the prevention of backwards-bending of the phialopore lips. Fluorescein-isothiocyanate-Con A bound to embryo and cell coat, ane more strongly to the embryo at pre-inversion. SDS-polyacrylamide gel analysis of proteins isolated from embryos showed 4 glycoprotein bands, but Con A binding to these bands could not be demonstrated.

scholarly journals Serum albumin is essential for in vitro growth of activated human lymphocytes.

1975 ◽  
Vol 142 (4) ◽  
pp. 949-959 ◽  
Author(s):  
H Polet ◽  
H Spieker-Polet
Keyword(s):  
Serum Albumin ◽  
Human Lymphocytes ◽  
In Vitro Growth ◽  
Con A ◽  
Promoting Effect ◽  
Purified Protein Derivative ◽  
Activated T Lymphocytes ◽  
Proliferation Of Lymphocytes ◽  
Albumin Molecule

The effect of human plasma, the plasma protein fractions of Cohn, and crystallized serum albumin on the in vitro growth of human lymphocytes activated by concanavalin A (Con A) or bacterial lipopolysaccharide was compared. It was found that fraction V or serum albumin (SA) is essential for growth of activated T and B lymphocytes. The other plasma proteins have no effect. The growth response of Con A-activated T lymphocytes to increasing concentrations of SA is similar to the response to increasing equivalent concentrations of plasma suggesting but not proving that SA is the only growth-stimulating factor in plasma when added to a protein-free culture medium. The growth-promoting effect of SA is not due to the fatty acids or hormones bound to SA but is attributed to the albumin molecule itself or to a factor tightly bound to it. SA can also effectively replace plasma to stimulate proliferation of lymphocytes activated by allogeneic lymphocytes or purified protein derivative of tuberculin.

Transport of RNA from nucleus to cytoplasm following mitogenic stimulation of human lymphocytes

1978 ◽  
Vol 56 (6) ◽  
pp. 659-666 ◽  
Author(s):  
Mary Mitchell ◽  
Enzo Bard ◽  
Rod L'Anglais ◽  
J. G. Kaplan
Keyword(s):  
Actinomycin D ◽  
Human Lymphocytes ◽  
Cell Types ◽  
Resting Cells ◽  
Con A ◽  
Mitogenic Stimulation ◽  
Gene Transcripts ◽  
Early Effects ◽  
Nucleolar Rna ◽  
Kinetics Of

An improved method affording clean separation of nuclei from cytoplasm was utilized to study the kinetics of appearance of [3H]uridine-labelled polyadenylated (poly(A)+) and nonpolyadenylated (poly(A)−) RNA in the cytoplasm of human lymphocytes stimulated with the mitogen concanavalin A (Con A). While our previous and present studies utilizing lymphocyte preparations purified on Ficoll-Hypaque gradients had shown that the earliest observable increase in labelled total cell RNA occurred after 12 h of exposure to Con A, we were here able to detect highly significant increases in levels of uridine-labelled poly(A)− RNA in the cytoplasm of lymphocytes which had been exposed to mitogen for 6 h; these cells had been pulsed with [3H]uridine for 2 h prior to harvest. This suggested that the early effects of mitogen may be to increase processing and transport of RNA rather than to increase the production of gene transcripts. At least 13 h of exposure to Con A was required before labelled poly(A)+ RNA appeared in the cytoplasmic extracts of stimulated cells and it did not appear in those of resting cells. The lag between addition of isotope and appearance of labelled RNA in cytoplasm was inversely related to the duration of incubation of the cells with mitogen. However, once the label appeared in the cytoplasm, its rate of appearance and its final level were similar at both 12 and 36 h of incubation with Con A. These kinetic data also suggest that mitogen acts mainly to accelerate the processing and transport of RNA at least during the first 12 h of mitogenic stimulation. A concentration (0.05 μg/ml) of actinomycin D which is known to inhibit specifically the transcription of nucleolar RNA in a variety of cell types was found to affect the transcription of poly(A)+ RNA in human lymphocytes; in some experiments, specific inhibition of nucleolar RNA synthesis was observed at 0.005 μg actinomycin D per millilitre.

scholarly journals Protective Effect on Human Lymphocytes of Some Flavonoids Isolated from Two Achillea Species

2010 ◽  
Vol 5 (5) ◽  
pp. 1934578X1000500 ◽  
Author(s):  
Ivana Aljancić ◽  
Miroslava Stanković ◽  
Vele Tešević ◽  
Ljubodrag Vujisić ◽  
Vlatka Vajs ◽  
...  
Keyword(s):  
Protective Effect ◽  
Human Lymphocytes ◽  
Chromosome Breakage ◽  
Inhibitory Effect ◽  
Positive Control ◽  
Proliferation Index ◽  
Chromosome Loss ◽  
Dependent Manner ◽  
Elevated Frequency

This study was conducted to elucidate the in vitro protective effect of five flavonoids [apigenin (1), apigenin-7- O-glucoside (2), centaureidin (3), jaceidin (4) and quercetin (5)] against chromosomal damage in mitogen-induced human lymphocytes. Using the Cytochalasin-B blocked micronucleus (CBMN) assay, in which the biomarker of chromosome breakage and/or chromosome loss is the elevated frequency of micronucleus (MN) in binucleated (BN) cells, the presence of flavonoid 2 in minimal concentration (3 μg/mL) gave a 35.5% decrease in the frequency of MN when compared with control human lymphocytes. The same concentration of flavonoids 1, 3 and 4, reduced the MN frequency by 24.4%, 28.0% and 28.0%, respectively. Higher concentrations (6 μg/mL and 10 μg/mL) seemed less effective. Flavonoid 5 (3 μg/mL) induced a slight decrease in MN frequency (5%), while higher doses (6 μg/mL and 10 μg/mL) provoked an increase of DNA damage. The comparable values for the cytokinesis-block proliferation index (CBPI) of the tested flavonoids and positive control suggested an inhibitory effect on lymphocyte proliferation. In the DPPH. scavenging assay, flavonoids 1-4 demonstrated modest activity, in a dose-dependent manner, compared with the synthetic antioxidants BHT and Trolox, while 5 exhibited comparably high antioxidative activity.

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