A Comparison of Multicast Feedback Control Mechanisms

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.

Download Full-text

Ca2+ Signaling in the Inner Ear

Physiology ◽

10.1152/physiol.00040.2006 ◽

2007 ◽

Vol 22 (2) ◽

pp. 131-144 ◽

Cited By ~ 33

Author(s):

Fabio Mammano ◽

Mario Bortolozzi ◽

Saida Ortolano ◽

Fabio Anselmi

Keyword(s):

Feedback Control ◽

Inner Ear ◽

Control Mechanisms ◽

Sensory Receptors ◽

Key Players ◽

Mechanical Disturbances

The inner ear contains delicate sensory receptors that have adapted to detect the minutest mechanical disturbances. Ca2+ ions are implicated in all steps of the transduction process, as well as in its regulation by an impressive ensemble of finely tuned feedback control mechanisms. Recent studies have unveiled some of the key players, but things do not sound quite right yet.

Download Full-text

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

EURASIP Journal on Bioinformatics and Systems Biology ◽

10.1186/1687-4153-2012-10 ◽

2012 ◽

Vol 2012 (1) ◽

Cited By ~ 20

Author(s):

Daniela Besozzi ◽

Paolo Cazzaniga ◽

Dario Pescini ◽

Giancarlo Mauri ◽

Sonia Colombo ◽

...

Keyword(s):

Feedback Control ◽

Control Mechanisms ◽

Pka Pathway

Download Full-text

Articulation and Stress/Juncture Production Under Oral Anesthetization and Masking

Journal of Speech and Hearing Research ◽

10.1044/jshr.1402.271 ◽

1971 ◽

Vol 14 (2) ◽

pp. 271-282 ◽

Cited By ~ 33

Author(s):

Sylvia A. Gammon ◽

Philip J. Smith ◽

Raymond G. Daniloff ◽

Chin W. Kim

Keyword(s):

Feedback Control ◽

Oral Cavity ◽

White Noise ◽

Speech Production ◽

Local Anesthesia ◽

The Other ◽

Control Mechanisms ◽

Combined Stress ◽

Noise Masking ◽

High Degree

Eight subjects, half of them naive and the other half aware of the purpose of the experiment, spoke 30 pairs of sentences involving the production of intricate stress/juncture patterns along with a passage containing all major consonant phonemes in English in various intraword positions. All subjects spoke all materials under: (1) normal conditions, (2) 110 dB re: 0.0002 ubar white noise masking, (3) extensive local anesthesia of the oral cavity, and (4) masking and anesthesia combined. Stress and juncture patterns were correctly produced despite all feedback disruption, and there was no difference between naive and aware subjects. Noise masking produced a decline in speech quality and a disruption of normal rhythm, both of which were even more seriously affected by anesthesia and anesthesia plus masking. There were no significant vowel misarticulations under any condition, but there was nearly a 20% rate of consonant misartiqulation under anesthesia and anesthesia and noise. Mis-articulation was most severe for fricatives and affricates in the labial and alveolar regions, presumably because these productions demand a high degree of precision of articulate shape and location and hence, intact feedback. Results are discussed in terms of feedback-control mechanisms for speech production.

Download Full-text

Prolactin Regulates Tuberoinfundibular Dopamine Neuron Discharge Pattern: Novel Feedback Control Mechanisms in the Lactotrophic Axis

Journal of Neuroscience ◽

10.1523/jneurosci.0129-12.2012 ◽

2012 ◽

Vol 32 (23) ◽

pp. 8074-8083 ◽

Cited By ~ 49

Author(s):

D. J. Lyons ◽

A. Hellysaz ◽

C. Broberger

Keyword(s):

Feedback Control ◽

Dopamine Neuron ◽

Discharge Pattern ◽

Control Mechanisms

Download Full-text

Modelling Robust Feedback Control Mechanisms That Ensure Reliable Coordination of Histone Gene Expression with DNA Replication

PLoS ONE ◽

10.1371/journal.pone.0165848 ◽

2016 ◽

Vol 11 (10) ◽

pp. e0165848

Author(s):

Andrea Christopher ◽

Heike Hameister ◽

Holly Corrigall ◽

Oliver Ebenhöh ◽

Berndt Müller ◽

...

Keyword(s):

Gene Expression ◽

Dna Replication ◽

Feedback Control ◽

Histone Gene ◽

Control Mechanisms ◽

Histone Gene Expression

Download Full-text

CoRa –A general approach for quantifying biological feedback control

10.1101/2020.10.09.334078 ◽

2020 ◽

Author(s):

Mariana Gómez-Schiavon ◽

Hana El-Samad

Keyword(s):

Feedback Control ◽

Control Systems ◽

General Framework ◽

Control Mechanism ◽

Biological Molecules ◽

Control Mechanisms ◽

Biological Processes ◽

Biological Feedback ◽

Feedback Systems ◽

Feedback Control Systems

AbstractFeedback control is a fundamental underpinning of life, underlying homeostasis of biological processes at every scale of organization, from cells to ecosystems. The ability to evaluate the contribution and limitations of feedback control mechanisms operating in cells is a critical step for understanding and ultimately designing feedback control systems with biological molecules. Here, we introduce CoRa –or ControlRatio–, a general framework that quantifies the contribution of a biological feedback control mechanism to adaptation using a mathematically controlled comparison to an identical system that does not contain the feedback. CoRa provides a simple and intuitive metric with broad applicability to biological feedback systems.

Download Full-text

Reaction to disturbances of a walking leg during stance

Journal of Experimental Biology ◽

10.1242/jeb.203.7.1211 ◽

2000 ◽

Vol 203 (7) ◽

pp. 1211-1223 ◽

Cited By ~ 3

Author(s):

C. Bartling ◽

J. Schmitz

Keyword(s):

Feedback Control ◽

Three Dimensional ◽

Force Transducer ◽

The Body ◽

Control Mechanisms ◽

Control Schemes ◽

Stick Insects ◽

Reaction Forces ◽

Negative Feedback Control ◽

Model Circuit

The ground reaction forces exerted by the legs of freely walking stick insects, Carausius morosus, were recorded during normal and perturbed locomotion. The animals walked along a path into which a three-dimensional force transducer was integrated. The transducer registered all three components of the forces produced by a single leg when, by chance, it walked on the force platform. The stiffness of the walking surface was found to be a critical variable affecting the forces and the trajectories of leg movements during undisturbed walking. The forces produced by a leg were considerably smaller and the trajectories were closer to the body during walking on soft versus stiff surfaces. Perturbations during stance were generated by moving the platform in various directions within the horizontal plane and at two different rates. Perturbations were applied either immediately after leg contact or after a delay of 300 ms. The reactions to these disturbances were compatible with the hypothesis that the velocity of leg movement is under negative feedback control. This interpretation is also supported by comparison with simulations based upon other control schemes. We propose a model circuit that provides a combination of negative and positive feedback control mechanisms to resolve the apparent discrepancies between our results and those of previous studies.

Download Full-text

Feedback control of the metaphase-anaphase transition in sea urchin zygotes: role of maloriented chromosomes.

The Journal of Cell Biology ◽

10.1083/jcb.126.1.189 ◽

1994 ◽

Vol 126 (1) ◽

pp. 189-198 ◽

Cited By ~ 31

Author(s):

G Sluder ◽

F J Miller ◽

E A Thompson ◽

D E Wolf

Keyword(s):

Feedback Control ◽

Sea Urchin ◽

Control Mechanisms ◽

Feedback Controls ◽

Anaphase Onset ◽

Molecular Events ◽

Chromosome Attachment ◽

Sphere Of Influence ◽

Chromosome Disjunction

To help ensure the fidelity of chromosome transmission during mitosis, sea urchin zygotes have feedback control mechanisms for the metaphase-anaphase transition that monitor the assembly of spindle microtubules and the complete absence of proper chromosome attachment to the spindle. The way in which these feedback controls work has not been known. In this study we directly test the proposal that these controls operate by maloriented chromosomes producing a diffusible inhibitor of the metaphase-anaphase transition. We show that zygotes having 50% of their chromosomes (approximately 20) unattached or monoriented initiate anaphase at the same time as the controls, a time that is well within the maximum period these zygotes will spend in mitosis. In vivo observations of the unattached maternal chromosomes indicate that they are functionally within the sphere of influence of the molecular events that cause chromosome disjunction in the spindle. Although the unattached chromosomes disjoin (anaphase onset without chromosome movement) several minutes after spindle anaphase onset, their disjunction is correlated with the time of spindle anaphase onset, not the time their nucleus breaks down. This suggests that the molecular events that trigger chromosome disjunction originate in the central spindle and propagate outward. Our results show that the mechanisms for the feedback control of the metaphase-anaphase transition in sea urchin zygotes do not involve a diffusible inhibitor produced by maloriented chromosomes. Even though the feedback controls for the metaphase-anaphase transition may detect the complete absence of properly attached chromosomes, they are insensitive to unattached or mono-oriented chromosomes as long as some chromosomes are properly attached to the spindle.

Download Full-text