Methods of experimental polyploidization and their use in apple breeding

2020 ◽  
Vol 62 ◽  
pp. 85-90
Author(s):  
L. V. Tashmatova ◽  
O. V. Matsneva ◽  
T. M. Khromova ◽  
V. V. Shakhov
Keyword(s):  
Exposure Time ◽  
Cell Walls ◽  
Prolonged Exposure ◽  
Ornamental Plants ◽  
Colchicine Treatment ◽  
Apple Trees ◽  
Open Ground ◽  
High Concentrations ◽  
Diploid Gametes

The article presents methods of experimental polyploidy of fruit, berry and ornamental plants. The purpose of this review is to highlight the problems and prospects of polyploidization of plants in the open ground and in vitro culture and the possibility of their application for apple trees. For the purpose of obtaining apple tetraploids as donors of diploid gametes, seed seedlings were treated with a solution of colchicine in concentrations of 0.1-0.4 % for 24 and 48 hours. Colchicine concentrations of 0.3 % and 0.4 % at 48 hours of treatment had a detrimental eff ect on their development. As a result, tetraploids and chimeras were obtained from seeds from free pollination of the varieties Orlik, Svezhest, Kandil Orlovsky, as well as from seeds obtained from crossing the varieties Svezhest×Bolotovskoe, Moskovskoe Оzherel’e×Imrus, Girlyanda×Venyaminovskoe. The optimal concentration of colchicine was 0.1 %. Methods of colchicine treatment have been studied: 1) adding to the nutrient medium, colchicine concentration: 0.01%, 0.02%, exposure time 24h-19 days; 2) applying amitotic solution to the growth point, colchicine concentration: 0.1 %, 0.2 %, exposure time 24h-7 days. To increase the penetration of colchicine through the cell walls, a 0.1 % dimexide solution was used. Studies have shown that high concentrations and prolonged exposure to colchicine reduce the viability of explants.

scholarly journals Low Doses of Methylmercury Induce the Proliferation of Thyroid Cells In Vitro Through Modulation of ERK Pathway

2020 ◽  
Vol 21 (5) ◽  
pp. 1556 ◽  
Author(s):  
Valentina Maggisano ◽  
Stefania Bulotta ◽  
Marilena Celano ◽  
Jessica Maiuolo ◽  
Saverio Massimo Lepore ◽  
...  
Keyword(s):  
Cell Viability ◽  
Prolonged Exposure ◽  
Signal Transduction Pathway ◽  
Immunoblot Analysis ◽  
Thyroid Cell ◽  
Promoting Effect ◽  
Thyroid Cells ◽  
M Phase ◽  
High Concentrations

Exposure to environmental endocrine disruptors has been associated with an increased frequency of thyroid pathology. In this study, we evaluated the effects of various concentrations of methylmercury (MeHg) on immortalized, non-tumorigenic thyroid cells (Nthy-ori-3-1). Exposure to MeHg at 2.5 and 5 µM for 24 h caused a reduction in cell viability with a decrease of the cell population in sub-G0 phase, as detected by MTT and flow cytometry. Conversely, MeHg at the lower concentration of 0.1 µM increased the cell viability with a rise of G2/M phase. An immunoblot analysis showed higher expression levels of phospho-ERK and not of phospho-Akt. Further enhancement of the cell growth rate was observed after a prolonged exposure of the cells up to 18 days to MeHg 0.1 µM. The present findings demonstrate the toxicity of high concentrations of MeHg on thyroid cells, while showing that treatment with lower doses of Hg, as may occur after prolonged exposure to this environmental contaminant, exerts a promoting effect on thyroid cell proliferation, by acting on the ERK-mediated pro-oncogenic signal transduction pathway.

STUDIES ON HYALINE MEMBRANES

PEDIATRICS ◽  
1961 ◽  
Vol 27 (4) ◽  
pp. 567-577
Author(s):  
Natalie Aronson
Keyword(s):  
Prolonged Exposure ◽  
Proteolytic Enzymes ◽  
Mouse Lung ◽  
Thioglycollic Acid ◽  
Hyaline Membranes ◽  
Human Lungs ◽  
High Concentrations ◽  
Dissolution In Vitro ◽  
Do So

Pulmonary hyaline membranes were studied by observations on their dissolution in vitro by proteolytic enzymes, by streptokinase and by urea with and without added thioglycollic acid. Pepsin, trypsin and chymotrypsin dissolved the hyaline membranes both in sections of human lungs as well as in sections of mouse lung with the experimentally produced disease, whereas streptokinase, alone, failed to do so. The combination of 8 molar urea with 2% thioglycollic acid partially removed the hyaline membranes from lung slices. These findings are consistent with the view that fibrin is an important component of pulmonary hyaline membranes. Four possible therapeutic agents were evaluated in the experimental disease in mice, produced by prolonged exposure to high concentrations of oxygen. Chymotrypsin, trypsin and chloropromazine did not influence the mortality rate or incidence of pulmonary lesions. Heparin treatment led to a striking increase in mortality and to an increased incidence of pulmonary hyaline membranes.

Bakterienwand und Tumorinduktion durch Agrobacterium tumefaciens / Bacterial Cell Wall and Tumor Induction by Agrobacterium tumefaciens

1973 ◽  
Vol 28 (3-4) ◽  
pp. 198-201 ◽  
Author(s):  
Rolf Beiderbeck
Keyword(s):  
Cell Wall ◽  
Agrobacterium Tumefaciens ◽  
Bacterial Cell ◽  
Cell Walls ◽  
Virulent Strain ◽  
Avirulent Strain ◽  
Tumor Induction ◽  
Induced Tumors ◽  
High Concentrations

Bacterial cell walls are concerned with the tumor induction by Agrobacterium tumefaciens on leaves of Kalanchoe in two different ways: 1. If an inoculum of the virulent strain B6 of A. tumefaciens is mixed with cells of the avirulent strain IIBNV6 or with high concentrations of cell wall preparations from B6 itself tumor induction is inhibited. The same is true with cell wall preparations which were treated with ether or chloroform. In vitro growth of the bacteria is not influenced by cell wall preparations. 2. Penicillin inhibits tumor induction by inhibiting bacterial growth. Addition of penicillin as late as 8 hours after infection is still inhibiting tumor initiation. Growth of induced tumors is not inihited by penicillin. The meaning of the two cell wall related processes in tumor induction is discussed.

Abstract 288: Use of hiPSC-Derived Cardiomyocytes to Explore Functional Cardiotoxicities of Direct Acting Antiviral Nucleoside Based Structures

2017 ◽  
Vol 121 (suppl_1) ◽  
Author(s):  
John P Imredy ◽  
Bharathi Balasubramanian ◽  
Armando Lagrutta ◽  
David B Olsen ◽  
Stephane Bogen ◽  
...  
Keyword(s):  
Prolonged Exposure ◽  
Induced Pluripotent Stem Cell ◽  
Direct Acting Antiviral ◽  
Base Substitutions ◽  
Beating Rate ◽  
High Concentrations ◽  
Direct Acting ◽  
The Impact ◽  
Antiviral Nucleoside

Nucleoside-derived structures constitute important Direct-Acting Antivirals (DAAs) for Hepatitis C Virus (HCV) treatment. BMS-986094 (BMS-094: a 2’-C-modified guanosine (G) derivative prodrug) was discontinued in phase II due to heart/kidney failure and cardiomyopathy, whereas sofosbuvir (a 2’-C-modified uridine prodrug) is an effective HCV DAA. Given the importance of purine nucleosides in cardiac signaling, we investigated BMS-094 in the human induced pluripotent stem cell derived cardiomyocyte (hiPSC-CM) model (iCells, CDI Fujifilm). Beating myocyte monolayer impedance signals were monituored for up to 7 days in the RTCA Cardio platform (ACEA-Biosystems). BMS-094 was acutely myotoxic at high concentrations (≥ 17 μM), as evidenced by cessation of myocyte beating and loss of baseline impedance or ‘Cell Index’ (C.I.), a measure of cell adherence, within hours. On prolonged exposure to BMS-094 at concentrations not associated with loss of C.I. (< 1 μM), we observed progressive, dose-dependent decreases in impedance amplitude (myocyte contractility) which were accompanied by increases in the spontaneous myocyte beating rate. The same beating phenotype could be elicited over a multi-day exposure duration by extracellular application of the BMS-094 core nucleoside (2’-C-methyl-guanosine) alone, but not by unmodified G. Loss of contractility with the G derivatives was accompanied by a decrease of the Ca 2+ transient amplitude in a Ca 2+ influx fluorescence assay (FDSS μCell, Hamamatsu). We investigated the impact of purine or pyrimidine base substitutions in the 2’-CMe-modified nucleoside: 2’-CMe-adenosine, -cytidine, -G, and -uridine. The uridine analog had the most limited effects on hiPSC-CMs beating parameters. The effect of 2’-CMe-cytidine on beating rate and impedance amplitude was similar to that of the G derivative, including a progressive multi-day onset. In contrast, 2’-CMe-adenosine slowed beating acutely, and led to loss of C.I. at higher concentrations. These results demonstrate the varied effects on CM function of base substitutions in antiviral nucleoside chemistry and support the utility of hiPSC-CMs as a model for screening in-vitro the potential cardiotoxicities of nucleoside derivative drugs.

Treatment of primary osteosarcoma with intra-arterial and intravenous high-dose methotrexate.

1983 ◽  
Vol 1 (7) ◽  
pp. 428-431 ◽  
Author(s):  
N Jaffe ◽  
J Prudich ◽  
J Knapp ◽  
Y M Wang ◽  
R Bowman ◽  
...  
Keyword(s):  
Exposure Time ◽  
Prolonged Exposure ◽  
High Dose ◽  
High Dose Methotrexate ◽  
Therapeutic Advantage ◽  
Dose Methotrexate ◽  
Primary Osteosarcoma ◽  
Finite Period ◽  
High Concentrations ◽  
High Doses

In an effort to achieve high concentrations and prolonged exposure times, high-dose methotrexate (MTX) was administered by the intra-arterial route over 6 hours at a dose of 12.5 g/m2 to nine patients with osteosarcoma. This was followed by citrovorum factor (CF) rescue, which was initiated 12 hours after completion of the infusion (MTX-CF). The regimen achieved high local concentrations over a finite period. No toxicity was encountered. Treatment was administered at weekly intervals, during which intravenous MTX-CF was interposed if facilities for intra-arterial administration were not available. However, despite increases in local venous concentrations and exposure times, only four of nine patients (44%) responded. This is similar to responses achieved with 7.5 g/m2 (48%) with CF initiated 2 hours after completion of the infusion. Higher MTX doses, intra-arterial administration, and prolongation of cytotoxic exposure time did not confer a therapeutic advantage as opposed to "conventional" intravenous high doses.

In Vitro Effects of Ethanol on Rabbit Platelet Aggregation, Secretion of Granule Contents, and Cyclic AMP Levels in the Presence of Prostacyclin

1989 ◽  
Vol 61 (02) ◽  
pp. 254-258 ◽  
Author(s):  
Margaret L Rand ◽  
Peter L Gross ◽  
Donna M Jakowec ◽  
Marian A Packham ◽  
J Fraser Mustard
Keyword(s):  
Cyclic Amp ◽  
Inhibitory Effect ◽  
Rabbit Platelet ◽  
Inhibitory Effects ◽  
Low Concentrations ◽  
Rabbit Platelets ◽  
High Concentrations ◽  
In Vitro Effects ◽  
Aggregation Of Platelets

SummaryEthanol, at physiologically tolerable concentrations, inhibits platelet responses to low concentrations of collagen or thrombin, but does not inhibit responses of washed rabbit platelets stimulated with high concentrations of ADP, collagen, or thrombin. However, when platelet responses to high concentrations of collagen or thrombin had been partially inhibited by prostacyclin (PGI2), ethanol had additional inhibitory effects on aggregation and secretion. These effects were also observed with aspirin- treated platelets stimulated with thrombin. Ethanol had no further inhibitory effect on aggregation of platelets stimulated with ADP, or the combination of ADP and epinephrine. Thus, the inhibitory effects of ethanol on platelet responses in the presence of PGI2 were very similar to its inhibitory effects in the absence of PGI2, when platelets were stimulated with lower concentrations of collagen or thrombin. Ethanol did not appear to exert its inhibitory effects by increasing cyclic AMP above basal levels and the additional inhibitory effects of ethanol in the presence of PGI2 did not appear to be brought about by further increases in platelet cyclic AMP levels.

Aggregation of Cat Platelets in Vitro

1970 ◽  
Vol 23 (03) ◽  
pp. 601-620 ◽  
Author(s):  
Th. B Tschopp
Keyword(s):  
Adenosine Monophosphate ◽  
Blood Collection ◽  
Base Line ◽  
Reversible Aggregation ◽  
Low Concentrations ◽  
Irreversible Aggregation ◽  
High Concentrations ◽  
Two Phases ◽  
Improved Technique

SummaryAggregation of cat platelets in the citrated plasma is examined by means of Born’s absorptiometer. A marked tendency of the platelets of this species to spontaneous aggregation necessitated first of all the development of an improved technique of blood collection.A hypothesis according to which 5-HT is released from the platelets, explains the absence of oscillations on the base line of the absorptiometer, the absence of platelet swelling, when ADP is added, and the effect of stirring on the aggregation curves in cat PRP. The average volume of cat platelets amounts to 10.46 μ3 when directly fixed in the blood, when fixed from PRP to 12.17 μ3, when fixed from stirred PRP to 13.51 μ3.In low concentrations (0.3-2 μM) ADP produce reversible aggregation; in narrowly restricted, individually dissimilar mean concentrations irreversible aggregation in two phases and in high concentrations, irreversible aggregation in one phase. Like ADP serotonin produces 2 phase irreversible aggregation in concentrations of 3-10 μM, but unlike ADP, the aggregation velocity decreases again with high 5-HT concentrations (>100 μM). Adrenaline does not produce aggregation and it is likely that adenosine and adenosine monophosphate inhibit the aggregation by serotonin but not by ADP. Species differences in the aggregation of human, rabbit and cat platelets are discussed.

Thrombin Generation Measured Ex Vivo Following Microvasculor Injury Is Increased in SLE Patients with Antiphospholipid-protein Antibodies

1997 ◽  
Vol 78 (04) ◽  
pp. 1173-1177 ◽  
Author(s):  
Jacek Musiał ◽  
Jakub Swadźba ◽  
Miłosz Jankowski ◽  
Marek Grzywacz ◽  
Stanisława Bazan-Socha ◽  
...  
Keyword(s):  
Lupus Erythematosus ◽  
Thrombin Generation ◽  
Ex Vivo ◽  
Skin Incision ◽  
Anticardiolipin Antibodies ◽  
Small Blood Vessel ◽  
Anionic Phospholipids ◽  
Increased Risk ◽  
High Concentrations

SummaryAntiphospholipid-protein antibodies (APA) include lupus-type anticoagulant (LA) and antibodies recognizing complexes of anionic phospholipids (e.g. cardiolipin) and proteins (e.g. prothrombin and (β2-glycoprotein I). The presence of APA is associated with an increased risk of both arterial and venous thrombosis. However, the pathogenic mechanism leading to thrombosis in patients with APA remains unclear. We studied 32 patients with systemic lupus erythematosus (SLE) who were divided into two groups depending on the presence (n = 19) or absence (n = 13) of APA. Healthy volunteers (n = 12) matched by age and sex served as controls. In all subjects LA and IgG class anticardiolipin antibodies (ACA) were determined. Thrombin generation was monitored ex vivo measuring fibrinopeptide A (FPA) and prothrombin fragment F1 + 2 (F1 + 2) in blood emerging from a skin microvasculature injury, collected at 30 second intervals. In subjects with antiphospholipid antibodies mean FPA and F1 + 2 concentrations were signiF1cantly higher at most blood sampling times than in controls. In some SLE patients with APA the process of thrombin generation was clearly disturbed and very high concentrations of F1brinopeptide A were detected already in the F1rst samples collected. Two minutes after skin incision SLE patients without APA produced slightly more FPA, but not F1 + 2, as compared to healthy subjects. Mathematical model applied to analyze the thrombin generation kinetics revealed that APA patients generated signiF1cantly greater amounts of thrombin than healthy controls (p = 0.02 for either marker). In contrast, in the same patients generation of thrombin in recalciF1ed plasma in vitro was delayed pointing to the role of endothelium in the phenomenon studied. In summary, these data show for the F1rst time that in SLE patients with antiphospholipid-protein antibodies thrombin generation after small blood vessel injury is markedly increased. Enhanced thrombin generation might explain thrombotic tendency observed in these patients.

Inhibition of Platelet Function by Antiarrhythmic Drugs, Verapamil and Disopyramide

1982 ◽  
Vol 47 (02) ◽  
pp. 150-153 ◽  
Author(s):  
P Han ◽  
C Boatwright ◽  
N G Ardlie
Keyword(s):  
Platelet Aggregation ◽  
Platelet Function ◽  
Antiarrhythmic Drugs ◽  
Adenosine Diphosphate ◽  
Inhibitory Effect ◽  
Second Phase ◽  
Ionophore A23187 ◽  
High Concentrations ◽  
Artery Disease

SummaryVarious cardiovascular drugs such as nitrates and propranolol, used in the treatment of coronary artery disease have been shown to have an antiplatelet effect. We have studied the in vitro effects of two antiarrhythmic drugs, verapamil and disopyramide, and have shown their inhibitory effect on platelet function. Verapamil, a calcium channel blocker, inhibited the second phase of platelet aggregation induced by adenosine diphosphate (ADP) and inhibited aggregation induced by collagen. Disopyramide similarly inhibited the second phase of platelet aggregation caused by ADP and aggregation induced by collagen. Either drug in synergism with propranolol inhibited ADP or collagen-induced platelet aggregation. Disopyramide at high concentrations inhibited arachidonic add whereas verapamil was without effect. Verapamil, but not disopyramide, inhibited aggregation induced by the ionophore A23187.

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