scholarly journals Interplay of cellular states: Role of delay as control mechanism

2019 ◽  
Author(s):  
Shakti Nath Singh ◽  
Athokpam Langlen Chanu ◽  
Md. Zubbair Malik ◽  
R. K. Brojen Singh
Keyword(s):  
Control Mechanism ◽  
Biological Systems ◽  
Stochastic Simulation Algorithm ◽  
Stationary Condition ◽  
System Failure ◽  
Universal Class ◽  
Delayed Reactions ◽  
Gene Regulatory ◽  
System Variables

Delay is everywhere, no matter how small or big it is. Experimental evidences show the existence and importance of time delayed reactions specially in biological systems. The role of delay is found to be multifunctional and is seemed to be system dependent. The analytically solved P(X,t) of gene regulatory process shows universal class of Poisson process at stationary condition. However, time delay creates a possible condition to the system to impart correlation in the stochastic process as sub-Poissonian or noise enhancement process which could be important in regulating and controlling the system. The results of simulation of few biological systems (gene regulation, circadian rhythm, and repressilator) using delay stochastic simulation algorithm show the possibilities of delay induced onset of oscillating states, which could be the active states of the systems, where, the system can establish coherence among the system variables, enhance the signal processing, optimize the system activities, etc. On the other hand, delay can also induce switching off of the oscillating states, which may correspond to inactive state or system failure.

Role of the Cilia Membrane in Control of Microtubule Sliding

1980 ◽  
Vol 38 ◽  
pp. 612-615
Author(s):  
Edna S. Kaneshiro
Keyword(s):  
Control Mechanism ◽  
Beat Frequency ◽  
Surface Membrane ◽  
Ciliary Membrane ◽  
Ciliary Beating ◽  
Ciliary Reversal ◽  
Voltage Dependent ◽  
Reversal Mechanism ◽  
And Function

It is currently believed that ciliary beating results from microtubule sliding which is restricted in regions to cause bending. Cilia beat can be modified to bring about changes in beat frequency, cessation of beat and reversal in beat direction. In ciliated protozoans these modifications which determine swimming behavior have been shown to be related to intracellular (intraciliary) Ca2+ concentrations. The Ca2+ levels are in turn governed by the surface ciliary membrane which exhibits increased Ca2+ conductance (permeability) in response to depolarization. Mutants with altered behaviors have been isolated. Pawn mutants fail to exhibit reversal of the effective stroke of ciliary beat and therefore cannot swim backward. They lack the increased inward Ca2+ current in response to depolarizing stimuli. Both normal and pawn Paramecium made leaky to Ca2+ by Triton extrac¬tion of the surface membrane exhibit backward swimming only in reactivating solutions containing greater than IO-6 M Ca2+ Thus in pawns the ciliary reversal mechanism itself is left operational and only the control mechanism at the membrane is affected. The topographic location of voltage-dependent Ca2+ channels has been identified as a component of the ciliary mem¬brane since the inward Ca2+ conductance response is eliminated by deciliation and the return of the response occurs during cilia regeneration. Since the ciliary membrane has been impli¬cated in the control of Ca2+ levels in the cilium and therefore is the site of at least one kind of control of microtubule sliding, we have focused our attention on understanding the structure and function of the membrane.

How do histone modifications contribute to transgenerational epigenetic inheritance in C. elegans?

2020 ◽  
Vol 48 (3) ◽  
pp. 1019-1034 ◽  
Author(s):  
Rachel M. Woodhouse ◽  
Alyson Ashe
Keyword(s):  
Histone Modifications ◽  
Molecular Mechanisms ◽  
Epigenetic Inheritance ◽  
Nematode Caenorhabditis Elegans ◽  
Histone Methyltransferases ◽  
Transgenerational Epigenetic Inheritance ◽  
C Elegans ◽  
Recent Developments ◽  
Gene Regulatory

Gene regulatory information can be inherited between generations in a phenomenon termed transgenerational epigenetic inheritance (TEI). While examples of TEI in many animals accumulate, the nematode Caenorhabditis elegans has proven particularly useful in investigating the underlying molecular mechanisms of this phenomenon. In C. elegans and other animals, the modification of histone proteins has emerged as a potential carrier and effector of transgenerational epigenetic information. In this review, we explore the contribution of histone modifications to TEI in C. elegans. We describe the role of repressive histone marks, histone methyltransferases, and associated chromatin factors in heritable gene silencing, and discuss recent developments and unanswered questions in how these factors integrate with other known TEI mechanisms. We also review the transgenerational effects of the manipulation of histone modifications on germline health and longevity.

scholarly journals The Gene Regulatory Roles of Herbal Extracts on the Growth, Immune System, and Reproduction of Fish

Animals ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 2167
Author(s):  
Ehsan Ahmadifar ◽  
Hamideh Pourmohammadi Fallah ◽  
Morteza Yousefi ◽  
Mahmoud A. O. Dawood ◽  
Seyed Hossein Hoseinifar ◽  
...  
Keyword(s):  
Immune System ◽  
Mode Of Action ◽  
Medicinal Herbs ◽  
Environmental Stressors ◽  
Fish Diet ◽  
Sustainable Aquaculture ◽  
Herbal Supplements ◽  
Aquatic Animals ◽  
Gene Regulatory

The crucial need for safe and healthy aquatic animals obligates researchers in aquaculture to investigate alternative and beneficial additives. Medicinal herbals and their extracts are compromised with diverse effects on the performances of aquatic animals. These compounds can affect growth performance and stimulate the immune system when used in fish diet. In addition, the use of medicinal herbs and their extracts can reduce oxidative stress induced by several stressors during fish culture. Correspondingly, aquatic animals could gain increased resistance against infectious pathogens and environmental stressors. Nevertheless, the exact mode of action where these additives can affect aquatic animals’ performances is still not well documented. Understanding the mechanistic role of herbal supplements and their derivatives is a vital tool to develop further the strategies and application of these additives for feasible and sustainable aquaculture. Gene-related studies have clarified the detailed information on the herbal supplements’ mode of action when administered orally in aquafeed. Several review articles have presented the potential roles of medicinal herbs on the performances of aquatic animals. However, this review article discusses the outputs of studies conducted on aquatic animals fed dietary, medicinal herbs, focusing on the gene expression related to growth and immune performances. Furthermore, a particular focus is directed to the expected influence of herbal supplements on the reproduction of aquatic animals.

The role of coherence in emergent behavior of biological systems

2015 ◽  
Vol 34 (2) ◽  
pp. 138-140 ◽  
Author(s):  
Marta Bertolaso ◽  
Antonio Capolupo ◽  
Christian Cherubini ◽  
Simonetta Filippi ◽  
Alessio Gizzi ◽  
...  
Keyword(s):  
Biological Systems ◽  
Emergent Behavior

Biopolymers: A comprehensive review

2022 ◽  
Vol 4 (1) ◽  
pp. 013-018
Author(s):  
Mohini Chandrashekhar Upadhye ◽  
Mohini Chetan Kuchekar ◽  
Rohini Revansiddhappa Pujari ◽  
Nutan Uttam Sable
Keyword(s):  
Pharmaceutical Industry ◽  
Food Packaging ◽  
Biological Systems ◽  
Review Article ◽  
Skin Care ◽  
Comprehensive Review ◽  
Green Nanotechnology ◽  
Biological Sources ◽  
Living Organisms

Biopolymers are compounds prepared by using various living organisms, including plants. These are composed of repeated units of the same or similar structure (monomers) linked together. Rubber, starch, cellulose, proteins and DNA, RNA, chitin, and peptides are some of the examples of natural biopolymers. Biopolymers are a diverse and remarkably versatile class of materials that are either produced by biological systems or synthesize from biological sources. Biopolymers are used in pharmaceutical industry and also in food industry.Naturally derived polymers are also used for conditioning benefits in hair and skin care. Biopolymers have various applications in medicine, food, packaging, and petroleum industries. This review article is focused on various aspects of biopolymers with a special emphasis on role of biopolymers in green nanotechnology and agriculture.

Role of fibrinopeptide B release: comparison of fibrins produced by thrombin and Ancrod

1977 ◽  
Vol 232 (6) ◽  
pp. H629-H633 ◽  
Author(s):  
L. L. Shen ◽  
J. Hermans ◽  
J. McDonagh ◽  
R. P. McDonagh
Keyword(s):  
Elastic Moduli ◽  
Slow Release ◽  
Control Mechanism ◽  
Gelation Time ◽  
Fibrin Gels ◽  
Lateral Association ◽  
Complete Digestion ◽  
Low Ionic Strength

The gelation time, opacity, light scattering, and elastic moduli of human fibrin gels clotted in the presence of thrombin, Ancrod, and Reptilase have been compared. At low ionic strength lateral association to thick fibers is observed in all cases. At all ionic strengths thrombin fibrin forms thicker fibers than does Ancrod fibrin. We have demonstrated that an increase in the extent of lateral association is linked to an increase in its velocity and to a decrease in the gelation time. One may consider the removal of fibrinopeptide B to act as a switch: after it is removed fibrin assembles rapidly to thick fibers and gelation is fast; but when this peptide is still attached, there is a slow assembly of thin fibers, and gelation, especially of dilute fibrin, is delayed. We believe that this delay is critical for the complete digestion by plasmin of fibrin formed during in vivo defibrination with Ancrod and of fibrin produced by very small amounts of thrombin (which would still contain fibrinopeptide B), and that slow release of fibrinopeptide B is part of a control mechanism for the regulation of fibrin formation and the prevention of intravascular coagulation.

Performance evaluation of alternate policies on reservoir system operation

1986 ◽  
Vol 13 (2) ◽  
pp. 203-212 ◽  
Author(s):  
J. R. Weeraratne ◽  
Lloyd Logan ◽  
T. E. Unny
Keyword(s):  
River System ◽  
Primary Objective ◽  
Performance Criteria ◽  
Decision Making Process ◽  
System Failure ◽  
System Operation ◽  
System Vulnerability ◽  
Operational Policies ◽  
System Robustness

This paper discusses within the context of the Grand River system operation the application of the three performance criteria introduced earlier by T. Hashimoto, D. P. Loucks, and J. R. Stedinger. These criteria evaluate the performance characteristic in respect to system failure, system recovery, and system vulnerability with regard to extreme (costly) failures for alternative operational policies. System robustness, also discussed by Hashimoto and co-workers, is used to measure the economic flexibility of system operation to adapt to uncertainties of future demand. The primary objective of the presentation made herein is to establish the role of these criteria in a decision-making process in the operation of the system.

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