The promotion of flowering in large field-grown Sitka spruce by girdling and stem injections of gibberellin A4/7

1985 ◽  
Vol 15 (1) ◽  
pp. 166-170 ◽  
Author(s):  
J. J. Philipson
Keyword(s):  
Environmental Conditions ◽  
Sitka Spruce ◽  
Large Field ◽  
Significant Stimulation ◽  
Stimulation Of

Mature 14-year-old grafted Piceasitchensis (Bong.) Carr. which were field grown and 6 m tall were given stem injections of gibberellin A4/7 (GA4/7) alone and in combination with girdling. The GA4/7 was applied twice, at 100 or 250 mg per application. GA4/7 alone produced a large and significant stimulation of the numbers of both pollen and seed cones, with means of about 200 pollen and 90 seed cones per tree, and 90% of the clones flowering; both levels of GA4/7 application stimulated flowering to approximately the same extent. The girdling treatment enhanced flowering when environmental conditions facilitated light flowering of the controls, and also increased the response to 100 mg GA4/7. The stimulation of flowering was carried over into the 2nd year after treatment, but only when both girdling and GA4/7 had been applied together.

Insulin stimulation of protein synthesis in cultured skeletal and cardiac muscle cells

1982 ◽  
Vol 243 (1) ◽  
pp. C81-C86 ◽  
Author(s):  
J. Airhart ◽  
J. A. Arnold ◽  
W. S. Stirewalt ◽  
R. B. Low
Keyword(s):  
Protein Synthesis ◽  
Specific Activity ◽  
Muscle Cells ◽  
Cell Types ◽  
Cardiac Cells ◽  
Cardiac Muscle Cells ◽  
Significant Stimulation ◽  
Chick Heart ◽  
Embryonic Chick Heart ◽  
Stimulation Of

The effects of acute exposure to insulin on protein synthesis were examined in primary, differentiated cultures of embryonic chick heart and skeletal muscle cells. Synthetic rates were calculated using the specific activity of tRNA-bound leucine as precursor, a specific activity that was significantly less than that of extracellular leucine but greater than that of free, intracellular leucine at 0.2 mM external leucine. Insulin did not alter these relationships. Doses of insulin in the physiological range produced significant stimulation of protein synthesis in both cell types. Maximal responses, involving approximately 30% increases in both absolute and fractional rates, were observed at higher insulin concentrations. Significant stimulation by insulin was seen in cardiac cells after only 1 h of insulin treatment, and the effects of the hormone were observed both in the presence and absence of serum in the culture medium.

The Effect of Stanozolol on the Fibrinolytic Enzyme System in Normal Subjects

1981 ◽  
Vol 26 (1_suppl) ◽  
pp. S59-S63 ◽  
Author(s):  
F. E. Preston
Keyword(s):  
Side Effects ◽  
Blood Coagulation ◽  
Enzyme System ◽  
Normal Subjects ◽  
Fibrinolytic Enzyme ◽  
Fibrinolytic System ◽  
Significant Stimulation ◽  
Volunteer Study ◽  
Coagulation And Fibrinolysis ◽  
Stimulation Of

In a volunteer study stanozolol was given in a dosage of 5mg twice per day for six weeks. A variety of parameters in blood coagulation and fibrinolysis were measured. Significant stimulation of the fibrinolytic system was found in seven days and this was associated with a significant fall in the levels of fibrinogen and alpha 2-macroglobulin. No major side effects were observed.

INVESTIGATION OF HORMETIC STIMULATION IN STRAWBERRY PLANTS USING IONIZING RADIATION

1987 ◽  
Vol 67 (4) ◽  
pp. 1181-1192 ◽  
Author(s):  
S. C. SHEPPARD ◽  
C. L. GIBB ◽  
J. L. HAWKINS ◽  
W. R. REMPHREY
Keyword(s):  
Ionizing Radiation ◽  
Field Trials ◽  
Early Growth ◽  
Dominant Factor ◽  
X Rays ◽  
X Ray ◽  
Significant Stimulation ◽  
Low Levels ◽  
The Individual ◽  
Stimulation Of

Hormesis is the stimulation of growth by very low levels of inhibitors or stressors. This phenomenon may be useful in crops where the usual cultural factors have been optimized. The literature indicates that substantial stimulation of early growth of strawberries (Fragaria × ananassa) could be achieved by exposing transplants to low doses of ionizing radiation. Experiments were conducted to test the effectiveness and reliability of X rays as a hormetic agent. Plants of a day-neutral cultivar Hecker and of a June-bearing cultivar Glooscap were irradiated at 0.5–16 Gy and planted in pots. The plants were grown outdoors and growth was recorded each week. Significant stimulation above the controls in the number of trifoliate leaves occurred in the day-neutral cultivar. This effect persisted until the first phase of fruiting. No significant stimulatory effects were observed at any time in the June-bearing cultivar. Two field trials with a June-bearing cultivar Redcoat, irradiated at doses of 0.5 and 2 Gy, also revealed no significant stimulation. The dominant factor regulating early growth was the size of the individual transplants. Therefore, although hormetic stimulation may occur, it will be difficult to quantify and optimize and it will not likely be useful for practical application.Key words: X ray, transplant, day-neutral, June-bearing

scholarly journals Caerulein and carbamoylcholine stimulate pancreatic amylase release at resting cytosolic free Ca2+

1986 ◽  
Vol 235 (1) ◽  
pp. 139-143 ◽  
Author(s):  
R Bruzzone ◽  
T Pozzan ◽  
C B Wollheim
Keyword(s):  
Fold Increase ◽  
Free Calcium ◽  
Amylase Secretion ◽  
Rapid Phase ◽  
Secretory Rate ◽  
Amylase Release ◽  
Pancreatic Acini ◽  
Significant Stimulation ◽  
Phase 0 ◽  
Stimulation Of

Cytosolic free calcium concentrations ([Ca2+]i) and amylase secretion were measured in isolated rat pancreatic acini loaded with the intracellularly trapped fluorescent indicator quin2. Both caerulein and carbamoylcholine caused a rapid increase in [Ca2+]i, with a maximal 3-fold increase at 10(-9) M-caerulein and 10(-4) M-carbamoylcholine. However, caerulein (10(-12) M and 10(-11) M) as well as carbamoylcholine (10(-7) M) caused a significant stimulation of amylase release, while not inducing any detectable rise in [Ca2+]i. Changes in [Ca2+]i after addition of either secretagogue were transient and did not last more than 2-3 min. By contrast, when amylase secretion was monitored as a function of time, two distinct secretory phases could be observed upon addition of either carbamoylcholine (10(-5) M) or caerulein (10(-10) M). An initial, rapid phase (0-5 min) which caused a 6-7-fold increase above basal, followed by a sustained (5-30 min), but less marked, secretory rate (2-3-fold above basal). Addition of atropine (10(-4) M) 5 min after carbamoylcholine (10(-5) M) (i.e. after termination of the rise in [Ca2+]i and of the first secretory phase) did not cause any significant change in [Ca2+]i, while significantly inhibiting amylase secretion from 5 to 30 min to the same rate observed in the absence of the secretagogue. These results show that caerulein and carbamoylcholine, two agents thought to activate secretion mainly through mobilization of Ca2+ from intracellular stores, are capable of eliciting amylase secretion independently of a concomitant rise in [Ca2+]i. Furthermore, with both secretagogues the rise in [Ca2+]i, when observed, was only transient, while the stimulation of amylase release was sustained.

scholarly journals The effect of cytokinins and other plant hormones on the growth of cotyledonary axilars of flax (Linum usitatissimum), sunflower (Helianthus annuus) and pea (Pisum sativum)

2011 ◽  
Vol 50 (No. 4) ◽  
pp. 182-187 ◽  
Author(s):  
Š. Klíčová ◽  
J. Šebánek ◽  
T. Vlašic
Keyword(s):  
Pisum Sativum ◽  
Helianthus Annuus ◽  
Plant Hormones ◽  
Linum Usitatissimum ◽  
The Other ◽  
Pea Seedlings ◽  
Significant Stimulation ◽  
The Difference ◽  
Intensive Growth ◽  
Stimulation Of

Flax seedlings were decapitated above the cotyledons. After one cotyledon was removed the growth of the bud of the remaining cotyledon was stronger in 90% of the plants. However, the application of the cytokinin benzyladenine (BA) to the bud of the removed cotyledon caused a growth correlative reversal and, by contrast, in 65% of the plants the bud of the removed cotyledon grew out. On the other hand, in sunflower seedlings, which have epigeal cotyledons similar to flax, after the removal of one cotyledon the growth of the axillary of the removed cotyledon was more intensive in 59% of the plants. Not even an application of BA to the remaining cotyledon of sunflower resulted in more intensive growth of the axillary of this cotyledon. When both cotyledons were left on the seedling, BA applied to one of the cotyledons of decapitated flax plants resulted in a highly significant stimulation of growth of the axillary of this cotyledon; in sunflower; however, the effect of the BA was insignificant. After decapitation of the stem of pea seedlings where both cotyledons remained, both axillaries grew out, but after a certain period of time one of them (the dominant one) achieved a growth correlative dominance over the other (inhibited). The present study is focused on whether an application of plant hormones onto the inhibited shoot is able to cause a growth correlative reversal, i.e. to change the inhibited shoot into a dominant one. The application of 0.12% BA can cause such a reversal virtually in all plants if the original difference in the length between the inhibited and dominating axillaries is 12–24 mm. A 0.12–0.5% concentration of gibberellin causes a reversal in 13–75% of the plants, but only if the difference between the dominant and inhibited shoot is 1–12 mm. A 0.03–0.25% concentration of IAA causes a reversal in 34–57% of the plants, if the difference in the length of the axillaries is 1–4 mm.

THE EFFECT OF PARATHYROID EXTRACT ON CELLULAR ACTIVITY AND PLASMA CALCIUM LEVELS IN VIVO

1969 ◽  
Vol 45 (3) ◽  
pp. 387-400 ◽  
Author(s):  
PATRICIA J. BINGHAM ◽  
IRIS A. BRAZELL ◽  
MAUREEN OWEN
Keyword(s):  
Rna Synthesis ◽  
Time Lag ◽  
Plasma Calcium ◽  
Cellular Activity ◽  
Maximum Increase ◽  
Cytoplasmic Rna ◽  
Significant Stimulation ◽  
Parathyroid Extract ◽  
Stimulation Of

SUMMARY Parathyroid hormone has a direct effect on the osteoclast population present at the time of administration of the hormone. There was a significant stimulation of nuclear RNA synthesis at the earliest time (1½ hr.) at which the measurement could be made. This is followed by increased production of cytoplasmic RNA which reaches its maximum after a considerable time-lag (7 to 12 hr. after parathyroid extract (PTE)). The increase in cytoplasmic RNA is accompanied by a corresponding stimulation of protein and mucoprotein synthesis in the osteoclasts and the effect persists at least until 24 hr. This time-lag and the relatively long duration of the effect on protein synthesis can be correlated approximately with the effect on the plasma calcium level. It is suggested therefore that the rise in plasma calcium is mainly due to the increased cellular activity of the osteoclasts and the resulting increased bone resorption. The opposite effect on the osteoblast system has about the same time-sequence and would complement the effect on the osteoclast system. At about the same time as the maximum increase in cellular activity in the osteoclasts is observed, a significant effect on RNA synthesis in the endosteal mesenchymal cells, the precursors of the osteoclasts, becomes apparent. This is closely followed by a rise in the number of osteoclasts which is first apparent at 17 hr. after PTE and is maximal by 24 hr. Consequently, the rise in the number of osteoclasts is a secondary effect and is not responsible for the initial rise in plasma calcium which occurred much earlier. It is suggested that the increase in osteoclast numbers follows as a result of the increased metabolic activity of the osteoclast population present when the hormone was injected. There is a depression of RNA synthesis in both the osteoblasts and their precursors, the preosteoblasts. This means that the hormone has opposite effects, not only on the osteoblasts and osteoclasts, but also on their respective precursors, indicating that osteoprogenitor cells contain a mixture of cells with two main lines, those differentiating in an osteoblastic or osteoclastic direction, respectively.

ENDOCRINE AND HISTOLOGICAL STUDIES ON OLIGOSPERMIC MEN TREATED WITH HUMAN PITUITARY AND CHORIONIC GONADOTROPHIN

1968 ◽  
Vol 40 (1) ◽  
pp. 107-115 ◽  
Author(s):  
D. M. de KRETSER ◽  
H. P. TAFT ◽  
J. B. BROWN ◽  
J. H. EVANS ◽  
B. HUDSON
Keyword(s):  
Testicular Biopsy ◽  
Chorionic Gonadotrophin ◽  
Plasma Testosterone ◽  
Human Pituitary ◽  
Results Of Treatment ◽  
Biopsy Specimens ◽  
Significant Stimulation ◽  
Histological Appearance ◽  
Cell Arrest ◽  
Stimulation Of

SUMMARY The results of treatment of three oligospermic men for periods of up to 12 months with human pituitary gonadotrophin alone and in combination with human chorionic gonadotrophin (Pregnyl) is described. The addition of exogenous gonadotrophin resulted in a small but significant stimulation of spermatogenesis which was confirmed by quantitative histological assessment of testicular biopsy specimens taken before, during and after treatment. The time taken for a response in the ejaculate appears to be dependent on the initial histological appearance of the testis, in particular the stage of germinal cell arrest. Estimations of plasma testosterone and urinary oestrogen indicate that testicular steroid biosynthesis is stimulated during treatment with gonadotrophin.

scholarly journals Impact of interacting climate change factors on growth and ochratoxin A production by Aspergillus section Circumdati and Nigri species on coffee

2016 ◽  
Vol 9 (5) ◽  
pp. 863-874 ◽  
Author(s):  
A. Akbar ◽  
A. Medina ◽  
N. Magan
Keyword(s):  
Climate Change ◽  
Ochratoxin A ◽  
Toxin Production ◽  
Aspergillus Ochraceus ◽  
Change Factors ◽  
Significant Stimulation ◽  
Coffee Beans ◽  
Higher Temperature ◽  
Stimulation Of ◽  
Lag Phases

The objectives of this study were to evaluate the effect of interacting climate change (CC) factors (water stress [water activity, aw; 0.99-0.90]); temperature [30, 35 °C]; and elevated CO2 [400 and 1000 ppm] on (1) lag phases prior to growth, (2) growth and (3) ochratoxin A (OTA) production by species of Aspergillus sections Circumdati and Nigri on coffee-based media and stored coffee beans. The lag phases, prior to growth, of all strains/species were slightly increased as aw, temperature and CO2 were modified. The interacting CC factors showed that most strains/species examined grew well at 30 °C and slightly less so at 35 °C except for Aspergillus niger (A 1911) which could tolerate the higher temperature. In addition, the interaction of elevated CO2 (1000 ppm) + temperature (35 °C) increased OTA production when compared with 30 °C but only for strains of Aspergillus westerdijkiae (B2), Aspergillus ochraceus (ITAL 14) and Aspergillus steynii (CBS 112814). Most of the strains had optimum growth at 0.95 aw at 35 °C, while at 30 °C the optimum was at 0.98 aw. On stored coffee beans there was only a significant stimulation of OTA production by A. westerdijkiae strains in elevated CO2 (1000) at 0.90 aw. These results suggest differential effects of CC factors on OTA production by species in the Sections Circumdati and Nigri in stored coffee and that for most species there is a reduction in toxin production.

Peptide histidine valine-42 stimulates gastric acid secretion in man

1989 ◽  
Vol 9 (3) ◽  
pp. 369-374 ◽  
Author(s):  
G. C. Nikou ◽  
Y. Yiangou ◽  
B. J. Chrysanthou ◽  
J. Domin ◽  
S. R. Bloom
Keyword(s):  
Gastric Secretion ◽  
Acid Secretion ◽  
Healthy Volunteers ◽  
Gastric Acid Secretion ◽  
Gastric Acid ◽  
Local Control ◽  
Significant Stimulation ◽  
New Finding ◽  
Stimulation Of

The effect of peptide histidine valine-42 (PHV-42) on gastric acid secretion was studied in man. PHV-42 was infused into 5 healthy volunteers at a dose of 10 pmol/kg/min. This dose caused a significant stimulation of basal gastric acid and potassium output. there were no significant changes in circulating gastrin throughout the infusion. In 2 subjects with a background of submaximal pentagastrin stimulation, PHV-42 infusion at the same dose did not alter acid secretion in either subject. The previous observation that PHV-42 is found particularly in the stomach and the new finding that it stimulates basal gastric secretion suggest the possibility that PHV-42 could have a role in local control of acid secretion.

scholarly journals PGE2 upregulates the Na+/K+ ATPase in HepG2 cells via EP4 receptors and intracellular calcium

PLoS ONE ◽  
2021 ◽  
Vol 16 (1) ◽  
pp. e0245400
Author(s):  
Rawad Hodeify ◽  
Mohamed Chakkour ◽  
Reem Rida ◽  
Sawsan Kreydiyyeh
Keyword(s):  
Intracellular Calcium ◽  
Hepg2 Cells ◽  
Live Cell Imaging ◽  
Cell Imaging ◽  
Time Lapse ◽  
Live Cells ◽  
Ionic Homeostasis ◽  
Significant Stimulation ◽  
Time Lapse Imaging ◽  
Stimulation Of

The Na+/K+ ATPase is a key regulator of the hepatocytes ionic homeostasis, which when altered may lead to many liver disorders. We demonstrated recently, a significant stimulation of the Na+/K+ ATPase in HepG2 cells treated with the S1P analogue FTY 720P, that was mediated through PGE2. The mechanism by which the prostaglandin exerts its effect was not investigated, and is the focus of this work. The type of receptors involved was determined using pharmacological inhibitors, while western blot analysis, fluorescence imaging of GFP-tagged Na+/K+ ATPase, and time-lapse imaging on live cells were used to detect changes in membrane abundance of the Na+/K+ ATPase. The activity of the ATPase was assayed by measuring the amount of inorganic phosphate liberated in the presence and absence of ouabain. The enhanced activity of the ATPase was not observed when EP4 receptors were blocked but still appeared in presence inhibitors of EP1, EP2 and EP3 receptors. The involvement of EP4 was confirmed by the stimulation observed with EP4 agonist. The stimulatory effect of PGE2 did not appear in presence of Rp-cAMP, an inhibitor of PKA, and was imitated by db-cAMP, a PKA activator. Chelating intracellular calcium with BAPTA-AM abrogated the effect of db-cAMP as well as that of PGE2, but PGE2 treatment in a calcium-free PBS medium did not, suggesting an involvement of intracellular calcium, that was confirmed by the results obtained with 2-APB treatment. Live cell imaging showed movement of GFP–Na+/K+ ATPase-positive vesicles to the membrane and increased abundance of the ATPase at the membrane after PGE2 treatment. It was concluded that PGE2 acts via EP4, PKA, and intracellular calcium.

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