scholarly journals The role of feedback control mechanisms on the establishment of oscillatory regimes in the Ras/cAMP/PKA pathway in S. cerevisiae

2012 ◽  
Vol 2012 (1) ◽  
Author(s):  
Daniela Besozzi ◽  
Paolo Cazzaniga ◽  
Dario Pescini ◽  
Giancarlo Mauri ◽  
Sonia Colombo ◽  
...  
Keyword(s):  
Feedback Control ◽  
Control Mechanisms ◽  
Pka Pathway

scholarly journals Using Regulatory Flexibility to Address Market Informality in Seed Systems: A Global Study

Agronomy ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 377
Author(s):  
Katrin Kuhlmann ◽  
Bhramar Dey
Keyword(s):  
Seed Quality ◽  
Regulatory Environment ◽  
Control Mechanisms ◽  
Seed Systems ◽  
High Quality ◽  
Design And Implementation ◽  
Key Dimensions ◽  
Regulatory Flexibility

Seed rules and regulations determine who can produce and sell seeds, which varieties will be available in the market, the quality of seed for sale, and where seed can be bought and sold. The legal and regulatory environment for seed impacts all stakeholders, including those in the informal sector, through shaping who can participate in the market and the quality and diversity of seed available. This paper addresses a gap in the current literature regarding the role of law and regulation in linking the informal and formal seed sectors and creating more inclusive and better governed seed systems. Drawing upon insights from the literature, global case studies, key expert consultations, and a methodology on the design and implementation of law and regulation, we present a framework that evaluates how regulatory flexibility can be built into seed systems to address farmers’ needs and engage stakeholders of all sizes. Our study focuses on two key dimensions: extending market frontiers and liberalizing seed quality control mechanisms. We find that flexible regulatory approaches and practices play a central role in building bridges between formal and informal seed systems, guaranteeing quality seed in the market, and encouraging market entry for high-quality traditional and farmer-preferred varieties.

Compensation Control Mechanisms in the American States

1989 ◽  
Vol 18 (3) ◽  
pp. 325-338 ◽  
Author(s):  
Wendell C. Lawther ◽  
Earle C. Traynham ◽  
Kenneth M. Jennings
Keyword(s):  
Collective Bargaining ◽  
State Government ◽  
Control Mechanisms ◽  
Compensation Control ◽  
Initial Analysis ◽  
Personnel Practices ◽  
State Compensation ◽  
American States

There are few studies which report on the personnel practices in the American states. A survey of state compensation analysts in the Summer of 1987 elicited information concerning the use of compensation controls in state government. Results indicate that with the exception of wage and salary surveys, data concerning compensation controls is rarely collected. Initial analysis indicates that the role of the legislature and the existence of collective bargaining may have an impact on the number of controls used.

A NEW APPROACH FOR INVESTIGATING HYPOTHALAMO-PITUITARY-GONADAL AND ADRENAL FEEDBACK CONTROL MECHANISMS: ACTIVE IMMUNIZATION WITH STEROIDS

1974 ◽  
Vol 76 (3) ◽  
pp. 556-569 ◽  
Author(s):  
E. Nieschlag ◽  
K. H. Usadel ◽  
H. K. Kley ◽  
U. Schwedes ◽  
K. Schöffling ◽  
...  
Keyword(s):  
Feedback Control ◽  
Leydig Cells ◽  
Positive Response ◽  
Active Immunization ◽  
Biologically Active ◽  
Control Group ◽  
Control Mechanisms ◽  
New Approach ◽  
Biological Neutralization ◽  
Group Serum

ABSTRACT A new method for the investigation of hypothalamo-pituitary-gonadal and adrenal feedback control mechanisms based on the biological neutralization of gonadal and adrenal steroids by active immunization is proposed. The regulatory influence of a given steroid in the feedback control is proved when reduction of the free, biologically active fraction of this steroid caused by antibody binding induces a positive response of the pituitary, thus effecting gonadal or adrenal hypertrophy and hyperfunction. The advantages and limitations of the new model are demonstrated by the effects of active immunization of rabbits with cortisol (F), aldosterone (Aldo), dehydroepiandrosterone (DHA), androstenedione (Δ4-A), testosterone (T), 5α-dihydrotestosterone (5α-DHT), 5β-DHT and oestradiol (E2). In the immunized animals and in a control group serum concentrations of total corticosteroids (TC), DHA, T, Δ4-A, E1, E2, LH and FSH, the percentage of binding of steroids in serum and the specificity of the antisera are determined. The testes are evaluated by histometry and the nuclear volume of the adrenocortical and Leydig cells is measured.

The Main Sequence of Human Optokinetic Afternystagmus (OKAN)

2009 ◽  
Vol 101 (6) ◽  
pp. 2889-2897 ◽  
Author(s):  
Andre Kaminiarz ◽  
Kerstin Königs ◽  
Frank Bremmer
Keyword(s):  
Neural Networks ◽  
Eye Movements ◽  
Main Sequence ◽  
Critical Role ◽  
Saccade Target ◽  
Control Mechanisms ◽  
Visually Guided ◽  
Background Characteristics ◽  
Optokinetic Afternystagmus

Different types of fast eye movements, including saccades and fast phases of optokinetic nystagmus (OKN) and optokinetic afternystagmus (OKAN), are coded by only partially overlapping neural networks. This is a likely cause for the differences that have been reported for the dynamic parameters of fast eye movements. The dependence of two of these parameters—peak velocity and duration—on saccadic amplitude has been termed “main sequence.” The main sequence of OKAN fast phases has not yet been analyzed. These eye movements are unique in that they are generated by purely subcortical control mechanisms and that they occur in complete darkness. In this study, we recorded fast phases of OKAN and OKN as well as visually guided and spontaneous saccades under identical background conditions because background characteristics have been reported to influence the main sequence of saccades. Our data clearly show that fast phases of OKAN and OKN differ with respect to their main sequence. OKAN fast phases were characterized by their lower peak velocities and longer durations compared with those of OKN fast phases. Furthermore we found that the main sequence of spontaneous saccades depends heavily on background characteristics, with saccades in darkness being slower and lasting longer. On the contrary, the main sequence of visually guided saccades depended on background characteristics only very slightly. This implies that the existence of a visual saccade target largely cancels out the effect of background luminance. Our data underline the critical role of environmental conditions (light vs. darkness), behavioral tasks (e.g., spontaneous vs. visually guided), and the underlying neural networks for the exact spatiotemporal characteristics of fast eye movements.

scholarly journals The cAMP-PKA Pathway Regulates Growth, Sexual and Asexual Differentiation, and Pathogenesis in Fusarium graminearum

2014 ◽  
Vol 27 (6) ◽  
pp. 557-566 ◽  
Author(s):  
Shuai Hu ◽  
Xiaoying Zhou ◽  
Xiaoying Gu ◽  
Shulin Cao ◽  
Chengfang Wang ◽  
...  
Keyword(s):  
Fusarium Graminearum ◽  
Vegetative Growth ◽  
Double Mutant ◽  
Elevated Temperatures ◽  
Hyphal Growth ◽  
Growth Defects ◽  
Plant Infection ◽  
Dependent Protein ◽  
Pka Pathway

Like many other filamentous ascomycetes, Fusarium graminearum contains two genes named CPK1 and CPK2 that encode the catalytic subunits of cyclic AMP (cAMP)-dependent protein kinase A (PKA). To determine the role of cAMP signaling in pathogenesis and development in F. graminearum, we functionally characterized these two genes. In addition, we generated and characterized the cpk1 cpk2 double and fac1 adenylate cyclase gene deletion mutants. The cpk1 mutant was significantly reduced in vegetative growth, conidiation, and deoxynivalenol production but it had increased tolerance to elevated temperatures. It was defective in the production of penetration branches on plant surfaces, colonization of wheat rachises, and spreading in flowering wheat heads. Deletion of CPK1 had no effect on perithecium development but the cpk1 mutant was defective in ascospore maturation and releasing. In contrast, the cpk2 mutant had no detectable phenotypes, suggesting that CPK2 contributes minimally to PKA activities in F. graminearum. Nevertheless, the cpk1 cpk2 double mutant had more severe defects in vegetative growth and rarely produced morphologically abnormal conidia. The double mutant, unlike the cpk1 or cpk2 mutant, was nonpathogenic and failed to form perithecia on self-mating plates. Therefore, CPK1 and CPK2 must have overlapping functions in vegetative growth, differentiation, and plant infection in F. graminearum. The fac1 mutant was also nonpathogenic and had growth defects similar to those of the cpk1 cpk2 mutant. However, deletion of FAC1 had no effect on conidium morphology. These results indicated that CPK1 is the major PKA catalytic subunit gene and that the cAMP-PKA pathway plays critical roles in hyphal growth, conidiation, ascosporogenesis, and plant infection in F. graminearum.

Abstract 207: Unc-51-like Kinase 1 (ULK1) Plays A Crucial Role In Mitophagy In Cardiomyocytes

2014 ◽  
Vol 115 (suppl_1) ◽  
Author(s):  
Toshiro Saito ◽  
Junichi Sadoshima
Keyword(s):  
Glucose Deprivation ◽  
High Ratio ◽  
Control Mechanisms ◽  
Oxygen Species ◽  
Predominant Role ◽  
Mitochondrial Quality Control ◽  
Over Expression ◽  
Pathological Conditions

The mitochondrion is an essential organelle that supplies ATP in cardiomyocytes (CMs). However, damaged mitochondria are harmful via the production of reactive oxygen species and induction of apoptosis in pathological conditions. Therefore, quality of mitochondria should be controlled tightly through various mitochondrial quality control mechanisms. Mitochondrial autophagy (mitophagy) is considered an integral part of this mechanism, and recent investigations uncovered the role of PINK1 and Parkin in mitophagy. However, these observations were made under artificial conditions, such as over-expression of Parkin or treatment with CCCP, and thus the precise mechanism has not been fully elucidated in more pathophysiologically relevant conditions. Recent evidence suggests that mitophagy can take place independently of ATG7, a molecule essential for the conventional form of autophagy, and that this form of autophagy is ULK1-dependent. We investigated the role of ULK1 and ATG7 in mediating mitophagy using mitochondria-targeted Keima (Mito-Keima) in cultured rat neonatal CMs. Keima has a bimodal excitation spectrum peaking at 440 and 560 nm, corresponding to the neutral and acidic pH, respectively. In CMs transfected with Mito-Keima, the fluorescent dots with a high 560nm/440nm ratio represent the mitochondria incorporated into autolysosomes which indicate mitophagy. Here we report that ULK1 plays a more predominant role in glucose deprivation (GD) -induced mitophagy than ATG7. Control CMs exhibited 8.7±1.0 % of the area of high-ratio dots per cells after GD. Knockdown of ULK1 significantly reduced the area to 2.3±0.9 % in CMs after GD (p<0.01, vs sh-Control). The reduction was significantly greater in CMs with knockdown of ULK1 than that of ATG7 (7.0±1.6 %, p<0.05, sh-ULK1 vs sh-ATG7). In addition, knockdown of Beclin1 and Drp1 also significantly decreased the area of high-ratio dots (about 1.0 % and 0.5 %, respectively). Overexpression of ULK1 was sufficient to induce mitophagy without starvation, whereas that of ATG7 was not. These results suggest that ULK1, Beclin1 and Drp1 play an essential role in mediating GD-induced mitophagy in CMs.

Pancreatic beta-cell electrical activity: the role of anions and the control of pH

1983 ◽  
Vol 244 (3) ◽  
pp. C188-C197 ◽  
Author(s):  
G. T. Eddlestone ◽  
P. M. Beigelman
Keyword(s):  
Membrane Potential ◽  
Cell Membrane ◽  
Beta Cell ◽  
Pancreatic Beta Cell ◽  
Proton Exchange ◽  
Disulfonic Acid ◽  
Control Mechanisms ◽  
Exchange System ◽  
Sodium Proton Exchange

The influence of chloride on the mouse pancreatic beta-cell membrane potential and the cell membrane mechanisms controlling intracellular pH (pHi) have been investigated using glass microelectrodes to monitor the membrane potential. It has been shown that chloride is distributed passively across the beta-cell membrane such that chloride potential is equal to the membrane potential. Withdrawal of perifusate chloride or bicarbonate and the application of the drugs 4-acetamido-4'-isethiocyanostilbene-2,2'-disulfonic acid (SITS) and probenecid, both blockers of transmembrane anion movement, have been used to establish that a chloride-bicarbonate exchange system is operative in the cell membrane and that it is one of the control mechanisms of pHi. Amiloride, a specific blocker of the transmembrane sodium proton exchange, has been used to demonstrate that this mechanism is also operative in the beta-cell membrane in the control of pHi. The hypothesis that the calcium-activated potassium permeability is proton sensitive at an intracellular site, a fall in pHi causing a fall in permeability and an increase in pHi causing an increase in permeability, has been used to explain many of the effects observed in this study.

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