Stimulation of rooting in vitro: effects of inhibitors of abscisic acid synthesis

1994 ◽  
pp. 299-302
Author(s):  
B. M. R. Harvey ◽  
C. Selby ◽  
G. Bowden
Keyword(s):  
Abscisic Acid ◽  
Acid Synthesis ◽  
In Vitro Effects ◽  
Stimulation Of

scholarly journals Contamination of erythropoietin by endotoxin: in vivo and in vitro effects on murine erythropoiesis

Blood ◽  
1979 ◽  
Vol 54 (1) ◽  
pp. 146-158 ◽  
Author(s):  
KS Zuckerman ◽  
PJ Quesenberry ◽  
J Levin ◽  
R Sullivan
Keyword(s):  
Significant Inhibition ◽  
Erythropoietic Activity ◽  
Limulus Amebocyte Lysate ◽  
Endogenous Erythropoietin ◽  
Significant Change ◽  
In Vitro Effects ◽  
Stimulation Of

Abstract Endotoxin was detected in all erythropoietin preparations tested and was removed from four lots, without loss of erythropoietic activity, by adsorption with limulus amebocyte lysate. Comparison of adsorbed (endotoxin-depleted) and nonadsorbed (endotoxin-containing) erythropoietin preparations demonstrated significant inhibition of CFU- e and BFU-e in vitro by nonadsorbed erythropoietin at concentrations higher than 0.25 U/ml and 2.0 U/ml, respectively. CFU-e and BFU-e were inhibited significantly by readdition in vitro of 10(-5)-10(-3) mug of endotoxin per unit of limulus-adsorbed erythropoietin. Administration of saline or 6 U of nonadsorbed or adsorbed erythropoietin twice a day for 4 days of CF1 mice resulted in reticulocyte counts of 2.1%, 9.9%, and 15.9%, respectively. Nonadsorbed erythropoietin resulted in a 29% decrease in erythropoiesis, a 42% decrease in CFU-e, and a 16% increase in granulopoiesis in the marrow, whereas adsorbed erythropoietin caused a 28% increase in erythropoiesis, no significant change in CFU-e and a 19% decrease in granulopoiesis in the marrow. Both preparations resulted in marked increases in splenic erythropoiesis and granulopoiesis. The effects of adsorbed erythropoietin are similar to those produced following stimulation of hematopoiesis by endogenous erythropoietin. Hemopoietic changes induced by nonadsorbed erythropoietin in vivo and in vitro are affected substantially by contamination of the erythropoietin preparations with endotoxin.

The effects of acetate and of pyruvate on the pathways of glucose catabolism in lactating mammary tissue. II. Sheep tissue

1969 ◽  
Vol 36 (3) ◽  
pp. 469-478 ◽  
Author(s):  
R. W. Smith ◽  
R. F. Glascock
Keyword(s):  
Pentose Phosphate Pathway ◽  
Acid Synthesis ◽  
Pentose Phosphate ◽  
Mammary Tissue ◽  
Glucose Catabolism ◽  
Glucose Carbon ◽  
Rat Tissue ◽  
The Relationship ◽  
Stimulation Of

SummaryA study was made of the changes in the rates of oxidation of the C(1), C(2) and C(6) atoms of glucose and in the pathways of glucose catabolism in sheep udder tissue in vitro which occurred when acetate and pyruvate were added.Whereas in rat mammary tissue the rate of oxidation of the C(1) atom of glucose was very much greater than that of the C(6) atom, the ratio of the rates of oxidation of these 2 atoms in sheep tissue was less than 2 when glucose was the only substrate.The addition of acetate resulted in an unequal stimulation of the oxidation of these 2 atoms, with the result that the ratio of their rates of oxidation was about doubled. The rate of oxidation of the C(2) atom was also increased.Acetate also increased the participation of the pentose phosphate pathway in glucose catabolism as measured by the incorporation of the C(1) and C(6) atoms of glucose into fatty acids, lactic acid and glycerol.Pyruvate produced little effect on the rate of oxidation of the C(1) atom but somewhat depressed that of the C(6) atom of glucose. At the same time, it caused a large increase in the participation of the pentose phosphate pathway.These results are discussed with reference to re-cycling of glucose carbon in the pentose phosphate pathway and to the relationship between that pathway and fatty acid synthesis. It is noted that the incorporation of glucose carbon into the 3 intermediates used gave values for the participation of that pathway which were in better agreement than was obtained in rat tissue. It is concluded that triose phosphates are more nearly in equilibrium in sheep than in rat mammary tissue.

Lipopeptides containing 2-(palmitoylamino)-6,7-bis(palmitoyloxy)heptanoic acid: synthesis, stereospecific stimulation of B-lymphocytes and macrophages and adjuvanticity in vivo and in vitro

1991 ◽  
Vol 34 (7) ◽  
pp. 1969-1974 ◽  
Author(s):  
Joerg Metzger ◽  
Guenther Jung ◽  
Wolfgang G. Bessler ◽  
Petra Hoffmann ◽  
Marianne Strecker ◽  
...  
Keyword(s):  
B Lymphocytes ◽  
Acid Synthesis ◽  
Heptanoic Acid ◽  
Stimulation Of

Gastric and duodenal HCO3- transport in vitro: effects of hormones and local transmitters

1982 ◽  
Vol 242 (2) ◽  
pp. G100-G110 ◽  
Author(s):  
G. Flemstrom ◽  
J. R. Heylings ◽  
A. Garner
Keyword(s):  
Phosphodiesterase Inhibitor ◽  
Duodenal Mucosa ◽  
Dibutyryl Camp ◽  
Inhibitory Peptide ◽  
Luminal Membrane ◽  
Wide Range ◽  
In Vitro Effects ◽  
Histamine H2 Antagonists ◽  
Stimulation Of

Luminal application of acid was recently shown to stimulate surface epithelial HCO3(-) transport in stomach and duodenum. Effects of some potential transmitters of this response were therefore studied in amphibian gastric fundic and proximal duodenal mucosa in vitro. Duodenal HCO3- transport, which could be titrated directly, was stimulated by dibutyryl cAMP (DBcAMP, 10(-6) M), the phosphodiesterase inhibitor 3-isobutyl-1-methylxanthine (10(-6) M), noradrenaline (10(-6) M), pancreatic glucagon (10(-8) M), and gastric inhibitory peptide (GIP, 10(-10) M). Stimulation by glucagon, but not by prostaglandin E2 (PGE2, 10(-6) M), required Cl- in the luminal solution and was prevented by furosemide (10(-3) M). This suggests that glucagon may affect HCO3(-)-Cl- exchange at the luminal membrane while transport stimulated by prostaglandins may be electrogenic. Stimulatory effects of glucagon and PGE2 were also additive. Gastric HCO3- transport, studied in tissues after inhibition of H+ secretion by histamine H2-antagonists, clearly differed from duodenum in that noradrenaline and GIP were inhibitory and DBcAMP was without effect. Stimulation of gastric HCO3- transport was observed with glucagon (10(-8) M), natural cholecystokinin (CCK, 10(-8) M), and CCK octapeptide (10(-7) M), CCK preparations had no effect in the duodenum. Although tested over a wide range of concentrations, no effect on either duodenal or gastric HCO3- transport was observed with histamine, pentagastrin, tetragastrin, urogastrone, ACTH, bombesin, motilin, secretin, serotonin, somatostatin, substance P, or vasoactive intestinal peptide.

Catecholamine stimulation of cyclic AMP and progesterone production in rat corpora lutea of different ages

1982 ◽  
Vol 100 (4) ◽  
pp. 613-622 ◽  
Author(s):  
Ensio Norjavaara ◽  
Gunnar Selstam ◽  
Kurt Ahrén
Keyword(s):  
Cyclic Amp ◽  
Corpora Lutea ◽  
Progesterone Production ◽  
Different Ages ◽  
Adrenergic Antagonists ◽  
Β Blocker ◽  
In Vitro Effects ◽  
Higher Doses ◽  
Stimulation Of

Abstract. In vitro effects of catecholamines (adrenaline and noradrenaline) and adrenergic antagonists on adenosine 3′,5′-cyclic monophosphate (cAMP) and progesterone production by rat corpora lutea (CL) of different ages (1–8 days old) were studied. To obtain defined ages of CL a pregnant mare's serum gonadotrophin (PMSG) model was used. The effect of catecholamines on cAMP decreased with luteal age while the effect on progesterone production was maximal on 5 day old CL. The β-blocker propranolol inhibited the effects of catecholamines in concentrations around 10−5 m. The effects of LH could only be inhibited with higher doses of propranolol known to exert unspecific effects. These results support the theory that LH and catecholamine effects on rat corpora lutea are mediated through different receptors.

scholarly journals In vitro effects of PCDDs/Fs on NK-like cell activity of Eisenia andrei earthworms

2012 ◽  
Vol 2 (1) ◽  
pp. 1
Author(s):  
Hayet Belmeskine ◽  
Sami Haddad ◽  
Louise Vandelac ◽  
Michel Fournier
Keyword(s):  
Flow Cytometry ◽  
Immune Function ◽  
Cell Activity ◽  
Eisenia Andrei ◽  
Significant Stimulation ◽  
In Vitro Effects ◽  
Tumoral Cells ◽  
Stimulation Of

In this study, we assessed<em> in vitro</em> the effects of PCDD/Fs on the NK-like cell activity in<em> Eisenia andrei</em> earthworms using flow cytometry for analysis. NK-like coelomocytes isolated from <em>E. andrei</em> and used as effectors were exposed to various concentrations of PCDDs/Fs mixture, C1 (6.25x10-3 ng 2378- TCDD/mL), C2 (12.5x10-3 ng 2378-TCDD/mL) and C3 (25x10-3 ng 2378-TCDD/mL), before adding them to human tumoral cells (K562) used as targets. We evaluated the percentage of targets lysed by Nk-like cells. The results showed a significant stimulation of the NKlike activity at C3 when PCDD/Fs were not removed from effectors before contact with targets, while no effects were noted when the effectors were washed (PCDD/Fs removed) or fixed. Assessment of the viability of the targets (K562), exposed alone and separately from effectors, to the three concentrations of PCDD/Fs, C1, C2 and C3, showed that all these concentrations were cytotoxic for K562. Results suggest that PCDD/Fs concentrations tested in this assay may be considered too low to induce suppressive effects on the immune function such as the NK-like activity in <em>E. andrei</em> earthworms.

scholarly journals The in vitro effects of Bordetella pertussis lymphocytosis-promoting factor on murine lymphocytes. III. B-cell dependence for T-cell proliferation.

1979 ◽  
Vol 149 (5) ◽  
pp. 1001-1017 ◽  
Author(s):  
M K Ho ◽  
A S Kong ◽  
S I Morse
Keyword(s):  
T Cell ◽  
T Cell Proliferation ◽  
Complement Receptors ◽  
Surface Immunoglobulin ◽  
Helper Cells ◽  
Mouse Immunoglobulin ◽  
In Vitro Effects ◽  
Cell Mitogen ◽  
Stimulation Of

The nature of the helper lymphocytes in lymphocytosis-promoting factor (LPF)-induced proliferation was explored. Removal of macrophages from adherent splenocytes by either carbonyl-iron incubation or passage through Sephadex G-10 columns did not affect their synergistic function. Nor did cytolysis with Thy-1.2 antiserum and complement. The helper cells were found to be surface immunoglobulin-positive (sIg+) because they are retained by anti-Ig columns, susceptible to lysis by rabbit anti-mouse immunoglobulin and complement, and occurred in the sIg+ fractions of splenocytes after separation on the fluorescence-activated cell sorter. Further delineation of the surface markers on helper cells showed that complement receptors are not the determining marker for synergistic function. The requirement for B-helper cells in the stimulation of T lymphocytes by LPF is unique for a mouse of T-cell mitogen.

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