scholarly journals Effect of GA3, IAA and their mixtures on the formation and development of cell systems in the vegetative and generative thallus of Chara vulgaris L.

2014 ◽  
Vol 60 (3-4) ◽  
pp. 313-326 ◽  
Author(s):  
Maria Kwiatkowska ◽  
Aleksandra Gosek ◽  
Mirosław Godlewski
Keyword(s):  
Inhibitory Effect ◽  
Main Axis ◽  
Stimulatory Action ◽  
Cell Systems ◽  
Low Concentration ◽  
Chara Vulgaris ◽  
Vegetative Part ◽  
Lateral Branches ◽  
High Level ◽  
Generative Organs

In concentrations ranging from 10<sup>-7</sup> to 10<sup>-5</sup> M IAA strongly stimulates the growth of the main axis and pleuridia internodal cells, while it does not affect the number of lateral branches and generative organs. In the higher concentrations it reduces the number of spermatozoids in the antheridium. In the same concentration range, GA<sub>3</sub>, inhibits the growth of the main axis and pleuridia internodal cells, does not affect the number of lateral branches, increases the number of antheridia and increases the number of forming spermatozoids. Incubation in mixture of both regulators has shown that: a) IAA eliminates the inhibitory effect of GA<sub>3</sub> on the growth of internodal cells of the main axis and its stimulatory action is slightly weakened by GA<sub>3</sub>, b) IAA in a concentration of 10<sup>-5</sup> M along with a low concentration of GA<sub>3</sub>, (10<sup>-7</sup>) increases the number of main axis lateral branches. The conclusion is drawn that the growth of the vegetative part of the thallus is more intense when auxin predominates, but generative development requires a high level of gibberellin.

scholarly journals The effect of cadmium on growth of vegetative thallus and development of generative organs of Chara vulgaris L. after short time of cultivation

2014 ◽  
Vol 66 (1) ◽  
pp. 67-72 ◽  
Author(s):  
Aleksandra Gosek ◽  
Maria Kwiatkowska ◽  
Robert Duszyński
Keyword(s):  
Main Axis ◽  
Cadmium Ions ◽  
Chara Vulgaris ◽  
Lateral Branches ◽  
Short Time ◽  
Number Of Cells ◽  
Generative Organs

The effect of cadmium ions in two different concentrations (10<sup>-8</sup>M i 10<sup>-6</sup>M) on vegetative thallus, male (antheridia) and femele (oogonia) generative organs of <em>Chara vulgaris</em> L. was investigated. After 9 days of growth in a presence of cadmium the number of lateral branches decreased and the lengths of internodes of the main axis and pleuridia became shortened. The increase in oospores volume and decrease in antheridial volume (both total and internal) after 3, 7 and 9 days of cultivation were observed. The productivity of antheridium measured by the number of antheridial filaments and number of cells within filament is also lower in plants cultivated with cadmium in comparison with control ones.

scholarly journals Effects of gibberellic acid and AMO-1618 on the development of vegetative systems in generatively matured thalli of Chara vulgaris L.

2014 ◽  
Vol 49 (4) ◽  
pp. 445-458 ◽  
Author(s):  
Maria Kwiatkowska ◽  
Mirosław Godlewski
Keyword(s):  
Gibberellic Acid ◽  
Mitotic Activity ◽  
Main Axis ◽  
Chara Vulgaris ◽  
Cell Divisions ◽  
Lateral Buds ◽  
Apical Cells ◽  
Axenic Conditions ◽  
High Level ◽  
Amo 1618

Effects of GA<sub>3</sub> (10<sup>-11</sup>-10<sup>-4</sup> M) and AMO-1618 (10<sup>-6</sup>-10<sup>-4</sup> M) on the development of generatively matured thalli of <em>Chara vulgaris</em> were investigated during 21-day culture of plants in axenic conditions. It has been found that in the main bud the divisions of apical cells of the thalli are not stimulated by GA<sub>3</sub>, whereas in the lateral buds the cell divisions are stimulated by higher GA<sub>3</sub> concentrations. Subsequent mitotic activity of the apical cells in the branches of the main axis is not stimulated by GA<sub>3</sub>, whereas the lateral buds of these branches are activated. The development of rhizoids in younger nodes is accelerated by high GA<sub>3</sub> concentrations. The elongation of the polynuclear, internodal cells of the main axis and that of pleuridia are inhibited proportionally to the GA<sub>3</sub> concentration. AMO-1618 stimulates the development of new nodes, elongation of internodes and delays the activation of lateral buds as well as the formation of rhizoids. These results suggest that the GA<sub>3</sub>-induced inhibition of elongation of the thalli and diminution of the apical domination is connected with a high level of endogenous gibberellins in the generatively matured thallus.

scholarly journals Comparative study of the vegetative and generative organs in pear varieties

2006 ◽  
Vol 12 (3) ◽  
Author(s):  
P. Dremák ◽  
G. Kocsisné Molnár
Keyword(s):  
Comparative Study ◽  
Relative Frequency ◽  
Main Axis ◽  
Point Of View ◽  
Lateral Branches ◽  
Generative Organs

An assortment of 17 pear varieties was examined in 2006 at Keszthely, Department of Horticulture, Georgicon Faculty of Agriculture, Veszprem University. The selected varieties were planted in 1980, grafted on seedling rootstock and represented the majority of existing pear plantations in Hungary. The main objective was the determination of suitability of the most important varieties for the purpose of intensive growing technologies even when grafted on vigorous seedling rootstock. The most important growing and fruiting characteristics of the varieties have been assessed and evaluated from the point of view of productivity. We stated that the relations of the trunk or the main axis to the lateral branches and fruiting structures are all subject to varietal effects and are valuable indices of the growing character. The quotient of the diameters of trunk and branch should be around 0.3-0.4, and the relative frequency of fruiting structures (Dárda, nyárs, vessző) meaning the ability of branching and regeneration associated with accurate pruning policies are decisive from the point of view of promising success.

Influence of N-methyl-d-aspartate on the reproductive axis of male Syrian hamsters

1993 ◽  
Vol 137 (2) ◽  
pp. 247-NP ◽  
Author(s):  
H. F. Urbanski ◽  
M. M. Fahy ◽  
P. M. Collins
Keyword(s):  
Hormone Secretion ◽  
Serum Testosterone ◽  
Inhibitory Effect ◽  
Stimulatory Action ◽  
Syrian Hamsters ◽  
Reproductive Axis ◽  
Treatment Paradigm ◽  
Testicular Size ◽  
Lh Releasing Hormone

ABSTRACT The influence of excitatory amino acids (EAAs) on reproductive neuroendocrine function was investigated in adult male Syrian hamsters of the LSH/Ss Lak strain. Before the study, the animals were maintained in a sexually regressed condition, under short days (SD) and subsequently were either transferred to long days (LD) or kept under SD, for a further 4 weeks. In the former group, photostimulation produced a predictable elevation in the hypophysial contents and serum concentrations of FSH and LH. This was accompanied by an increase in testicular size, an elevation in serum testosterone levels and an increase in spermatogenic activity; the SD hamsters remained sexually quiescent throughout the study. In contrast, SD hamsters that were given daily injections of the EAA agonist, N-methyl-d,l-aspartate (NMA: 50 mg/kg body weight, s.c.), showed stimulatory responses that were generally even more pronounced than those shown by the LD group. Surprisingly, an identical NMA treatment paradigm failed to cause a similar activation of the reproductive axis in LD hamsters that were given daily afternoon injections of melatonin (25 μg, s.c), even though the inhibitory effect of this melatonin treatment is generally regarded as being comparable with that produced by exposure to SD. Although EAAs can acutely stimulate the neurocircuitry that controls LH-releasing hormone secretion, the present findings suggest that EAAs might also exert a long-term stimulatory action by acting further upstream in the photoneuroendocrine pathway. Journal of Endocrinology (1993) 137, 247–252

Effects of glucocorticoids on prostaglandin formation by human amnion

1990 ◽  
Vol 68 (6) ◽  
pp. 671-676 ◽  
Author(s):  
William Gibb ◽  
Jean-Claude Lavoie
Keyword(s):  
Calcium Ionophore ◽  
Inhibitory Effect ◽  
Calcium Ionophore A23187 ◽  
Ionophore A23187 ◽  
Isolated Cells ◽  
Stimulatory Action ◽  
Human Amnion ◽  
Human Labor ◽  
Epidermal Growth

The human amnion may be an important source of prostaglandins involved in the onset of human labor and therefore it is important to define the factors that regulate their formation in this tissue. In the present study we demonstrate that glucocorticoids inhibit prostaglandin production by freshly isolated amnion cells. The inhibitory action of the glucocorticoids, however, changes to a stimulatory action when the cells are maintained in primary culture for a few days. For both inhibition and stimulation, concentrations of 10−8 M dexamethasone or greater were required to give significant effects, and estradiol and progesterone had no effect on the prostaglandin output of the cells. Epidermal growth factor (EGF), which has previously been found to stimulate prostaglandin output by confluent amnion cells, did not alter prostaglandin output of cells initially placed in culture. Furthermore, the stimulatory action of EGF and dexamethasone appeared additive. The calcium ionophore A23187 stimulated prostaglandin output in freshly isolated cells and accentuated the inhibitory effect of dexamethasone. These studies indicate that prostaglandin formation by human amnion during pregnancy could be regulated by glucocorticoids. These steroids are easily available to the amnion by way of cortisone conversion to Cortisol by the maternal decidua. The results also indicate that amnion is capable of responding to glucocorticoids in both a stimulatory and inhibitory fashion and whether one or both actions are of importance in vivo is a question that is as yet unresolved.Key words: prostaglandins, amnion, fetal membranes, glucocorticoids, labor, pregnancy.

scholarly journals The effect of light factor on the development of thallus and generative organs in Chara vulgaris L.

2014 ◽  
Vol 49 (4) ◽  
pp. 397-407 ◽  
Author(s):  
Janusz Maszewski
Keyword(s):  
Mitotic Activity ◽  
Axenic Culture ◽  
Light Period ◽  
Continuous Illumination ◽  
Chara Vulgaris ◽  
The Moment ◽  
Almost All ◽  
Effect Of Light ◽  
Generative Organs

During long-term axenic culture of Chara continuous illumination (L=24) increases mitotic activity of almost all types of cells. In such conditions only initiation of oogonia is inhibited, leading into a strong predomination of male generative organs. Prolonged darkness (L:D=1:23) exerts a mitodepressing effect. Oogonia and antheridia are especially susceptible to the reduction of the light period. Modifications of the elongating growth in various photoperiods are different in the polyploid regions of the vegetative thallus and in haploid cells of the antheridial filaments. Segments of both axial internodes and lateral pleuridia increase their dimensions at L:D=1:23, whereas at L=24 their growth is significantly inhibited. Different reaction is noted in the cells of antheridial filaments: at L=24 they are about 10% longer than in the control (L:D=14:10). The duration of the antheridium aevelopment, from the stage of unicellular filaments to the moment of antheridium opening, is 1.5 days shorter at L=24 as compared with the control. This shortening includes proportionally both the period of divisions within antheridial filaments and the period of spermatozoid differentiation.

EFFECTS OF HYDROXYSTEROID DEHYDROGENASE INHIBITORS ON IN-VITRO AND IN-VIVO STEROIDOGENESIS IN THE OVINE ADRENAL GLAND

1982 ◽  
Vol 92 (2) ◽  
pp. 205-212 ◽  
Author(s):  
P. SINGH-ASA ◽  
G. JENKIN ◽  
G. D. THORBURN
Keyword(s):  
Adrenal Gland ◽  
Incubation Medium ◽  
Bovine Serum ◽  
Hydroxysteroid Dehydrogenase ◽  
Inhibitory Effect ◽  
Bovine Serum Albu ◽  
Stimulatory Action ◽  
Adrenal Steroidogenesis

The effectiveness of trilostane and azastene as inhibitors of adrenal steroidogenesis was compared by in-vitro and in-vivo methods. A radioimmunoassay was developed for the measurement of cortisol in ovine plasma, incubation medium and tissue extract using a specific antiserum raised against cortisol 21-acetate,3-carboxymethyloxime : bovine serum albu Trilostane (20 μmol/l) decreased cortisol synthesis and release both in unstimulated and in ACTH-stimulated adrenal tissues in vitro. The same concentration of azastene had a lesser effect on unstimulated adrenals and was completely ineffective in blocking the stimulatory action of ACTH. In vivo, trilostane suppressed adrenal steroidogenesis in pregnant and cyclic ewes but the suppression in pregnant ewes was over a longer period, and after lower doses. It is concluded that trilostane had an inhibitory effect on ovine adrenal steroidogenesis both in vitro and in vivo.

Kinetic studies on transport of PAH and other organic acids in isolated renal tubules

1965 ◽  
Vol 208 (2) ◽  
pp. 391-396 ◽  
Author(s):  
K. C. Huang ◽  
Dorothy S. T. Lin
Keyword(s):  
Organic Acids ◽  
Partition Coefficient ◽  
Transport Mechanism ◽  
Hippuric Acid ◽  
Kinetic Studies ◽  
Inhibitory Effect ◽  
Renal Tubules ◽  
High Concentration ◽  
Low Concentration ◽  
Tubular Transport

Studies were made on the uptake and washout of PAH and other organic acids in isolated renal tubules and cells at 25 C. The renal tubules accumulated PAH rapidly in the first 30-min period. Probenecid, its diethyl- and dimethyl analogues, hippuric acid, and 2,4-dinitrophenol inhibited the tubular transport of PAH competitively. A relationship between the inhibitory effect and the partition coefficient of the compound was observed; the higher the partition coefficient, the greater the inhibition. DNP was also accumulated in the isolated renal tubules. This accumulation was depressed by probenecid, indicating that DNP is probably transported by the same tubular transport mechanism for PAH and other organic acids. In washout experiments probenecid and DNP showed a biphasic action, namely, they stimulated the PAH washout in low concentration and inhibited it in high concentration However, hippuric acid, which has a low partition coefficient, demonstrated an augmentation of PAH washout even at a concentration of 2 x 10–2 m

Calcium in the control of renin secretion: Ca2+ influx as an inhibitory signal

1981 ◽  
Vol 240 (1) ◽  
pp. F70-F74 ◽  
Author(s):  
C. S. Park ◽  
D. S. Han ◽  
J. C. Fray
Keyword(s):  
Incubation Temperature ◽  
Inhibitory Effect ◽  
Renin Secretion ◽  
Juxtaglomerular Cells ◽  
Stimulatory Action ◽  
Inhibitory Signal ◽  
Ca Antagonist ◽  
K Concentration ◽  
Energy Dependent

The mechanism for the inhibition of renin secretion in vitro from renal cortical slices by angiotensin II, antidiuretic hormone, ouabain, and high K+ concentration was studied. The inhibitory effect of these agents was blocked by a Ca antagonist, verapamil. In addition, epinephrine stimulated renin secretion and its stimulatory action was blocked by ouabain. These results support the hypothesis that Ca2+ influx into juxtaglomerular cells plays a role as an inhibitory signal whereas Ca2+ efflux is a stimulatory signal for renin secretion. Renin secretion was greatly stimulated by lowering incubation temperature, indicating that renin secretion is not energy dependent. The possibility is discussed that Ca2+ of juxtaglomerular cells might activate an enzyme(s) that then modulates some sequential steps of renin secretory processes, thereby controlling the rate of renin secretion.

scholarly journals Prostaglandin E1 inhibits endocytosis in the β-cell endocytosis

2016 ◽  
Vol 229 (3) ◽  
pp. 287-294 ◽  
Author(s):  
Ying Zhao ◽  
Qinghua Fang ◽  
Susanne G Straub ◽  
Manfred Lindau ◽  
Geoffrey W G Sharp
Keyword(s):  
Inhibitory Effect ◽  
Prostaglandin E ◽  
Β Cell ◽  
Α Subunit ◽  
Capacitance Measurements ◽  
Readily Releasable Pool ◽  
Whole Cell Patch Clamp ◽  
C Terminus ◽  
High Level

Prostaglandins inhibit insulin secretion in a manner similar to that of norepinephrine (NE) and somatostatin. As NE inhibits endocytosis as well as exocytosis, we have now examined the modulation of endocytosis by prostaglandin E1 (PGE1). Endocytosis following exocytosis was recorded by whole-cell patch clamp capacitance measurements in INS-832/13 cells. Prolonged depolarizing pulses producing a high level of Ca2+ influx were used to stimulate maximal exocytosis and to deplete the readily releasable pool (RRP) of granules. This high Ca2+ influx eliminates the inhibitory effect of PGE1 on exocytosis and allows specific characterization of the inhibitory effect of PGE1 on the subsequent compensatory endocytosis. After stimulating exocytosis, endocytosis was apparent under control conditions but was inhibited by PGE1 in a Pertussis toxin-sensitive (PTX)-insensitive manner. Dialyzing a synthetic peptide mimicking the C-terminus of the α-subunit of the heterotrimeric G-protein Gz into the cells blocked the inhibition of endocytosis by PGE1, whereas a control-randomized peptide was without effect. These results demonstrate that PGE1 inhibits endocytosis and Gz mediates the inhibition.

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