scholarly journals Differential Expression and Internal Feedback Regulation of 1-Aminocyclopropane-1-Carboxylate Synthase, 1-Aminocyclopropane-1-Carboxylate Oxidase, and Ethylene Receptor Genes in Tomato Fruit during Development and Ripening

1998 ◽  
Vol 118 (4) ◽  
pp. 1295-1305 ◽  
Author(s):  
Akira Nakatsuka ◽  
Shiho Murachi ◽  
Hironori Okunishi ◽  
Shinjiro Shiomi ◽  
Ryohei Nakano ◽  
...  
Keyword(s):  
Differential Expression ◽  
Tomato Fruit ◽  
Feedback Regulation ◽  
Ethylene Receptor ◽  
Internal Feedback

A UV-light activated cinnamic acid isomer regulates plant growth and gravitropism via an ethylene receptor-independent pathway

1999 ◽  
Vol 26 (4) ◽  
pp. 325 ◽  
Author(s):  
Xiao Xian Yang ◽  
Hiu Wan Choi ◽  
Shang Fa Yang ◽  
Ning Li
Keyword(s):  
Tomato Plant ◽  
Uv Light ◽  
Tomato Fruit ◽  
Ethylene Biosynthesis ◽  
Banana Fruit ◽  
Ethylene Receptor ◽  
Cinnamic Acids ◽  
Tomato Plants ◽  
Tomato Fruit Ripening ◽  
Negative Gravitropism

Naturally occurring cinnamic acids (CA) exist in both trans- and cis-isoforms. UV-light irradiation of trans-CA is able to produce cis-CA. cis-CA was found to possess auxin-like activity before. In contrast, the vapor of cis-CA induced an epinastic response in tomato plants just as ethylene does. Given the existence of a double bond in and the gaseous nature of cis-CA, we suspected that cis-CA might also function as an ethylene-like compound. To distinguish between these possibilities, we selected an ethylene perception-deficient tomato plant, Never-ripe (Nr), and an ethylene biosynthesis-deficient tomato plant, A11. Not only did the vapor of cis-CA fail to trigger A11 tomato fruit ripening but it also delayed the ripening of banana fruit. Moreover, the vapor of cis-CA induced epinasty and the ‘triple response’ in both the wild type and Nr tomato plants, indicating that the vapor of cis-CA does not act via an ethylene receptor-dependent pathway. Furthermore, the vapor of cis-CA inhibited the negative gravitropic response of stems of both etiolated Nr seedlings and young plants, whereas ethylene had little effect on the negative gravitropism of the Nr plants. These results support the conclusion that the action sites of the vapor of cis-CA and ethylene are fundamentally different.

CONTROLLING SYNCHRONIZATION IN A NEURON-LEVEL POPULATION MODEL

2007 ◽  
Vol 17 (02) ◽  
pp. 123-138 ◽  
Author(s):  
NIRANJAN CHAKRAVARTHY ◽  
SHIVKUMAR SABESAN ◽  
LEON IASEMIDIS ◽  
KOSTAS TSAKALIS
Keyword(s):  
Population Model ◽  
Adaptive Systems ◽  
Feedback Regulation ◽  
High Amplitude ◽  
Level Population ◽  
External Control ◽  
Internal Feedback ◽  
Control Paradigm ◽  
Neural Populations ◽  
Synchronous Behavior

We have studied coupled neural populations in an effort to understand basic mechanisms that maintain their normal synchronization level despite changes in the inter-population coupling levels. Towards this goal, we have incorporated coupling and internal feedback structures in a neuron-level population model from the literature. We study two forms of internal feedback — regulation of excitation, and compensation of excessive excitation with inhibition. We show that normal feedback actions quickly regulate/compensate an abnormally high coupling between the neural populations, whereas a pathology in these feedback actions can lead to abnormal synchronization and "seizure"-like high amplitude oscillations. We then develop an external control paradigm, termed feedback decoupling, as a robust synchronization control strategy. The external feedback decoupling controller acts to achieve the operational objective of maintaining normal-level synchronous behavior irrespective of the pathology in the internal feedback mechanisms. Results from such an analysis have an interesting physical interpretation and specific implications for the treatment of diseases such as epilepsy. The proposed remedy is consistent with a variety of recent observations in the human and animal epileptic brain, and with theories from nonlinear systems, adaptive systems, optimization, and neurophysiology.

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