System analysis of Phycomyces light-growth response. Photoreceptor and hypertropic mutants

A. Palit; P. Pratap; E. D. Lipson

doi:10.1016/S0006-3495(86)83506-8

System analysis of Phycomyces light-growth response. Photoreceptor and hypertropic mutants

A. Palit, P. Pratap, E. D. Lipson

Department of Physics

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9 Scopus citations

Abstract

The light-growth responses of Phycomyces behavioral mutants, defective in genes madB, madC, and madH, were studied with the sum-of-sinusoids method of system identification. Modified phototropic action spectra of these mutants have indicated that they have altered photoreceptors (P. Galland and E.D. Lipson, 1985, Photochem. Photobiol. 41:331). In the two preceding papers, a kinetic model of the light-growth response system was developed and applied to wild-type frequency kernels at several wavelengths and temperatures. The present mutant studies were conducted at wavelength 477 nm. The log-mean intensity was 6 X 10(-2)W m-2 for the madB and madC night-blind mutants, and 10(-4)W m-2 for the madH hypertropic mutant. The prolonged light-growth responses of the madB and madC mutants are reflected in the reduced dynamic order of their frequency kernels. The linear response of the hypertropic mutant is essentially normal, but its nonlinear behavior shows modified dynamics. The behavior of these mutants can be accounted for by suitable modifications of the parametric model of the system. These modifications together support the hypothesis that an integrated complex mediates sensory transduction in the light responses and other responses of the sporangiophore.

Original language	English (US)
Pages (from-to)	661-668
Number of pages	8
Journal	Biophysical Journal
Volume	50
Issue number	4
DOIs	https://doi.org/10.1016/S0006-3495(86)83506-8
State	Published - 1986

ASJC Scopus subject areas

Biophysics

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10.1016/S0006-3495(86)83506-8

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@article{29b30292dd444067905ba19eed45001f,

title = "System analysis of Phycomyces light-growth response. Photoreceptor and hypertropic mutants",

abstract = "The light-growth responses of Phycomyces behavioral mutants, defective in genes madB, madC, and madH, were studied with the sum-of-sinusoids method of system identification. Modified phototropic action spectra of these mutants have indicated that they have altered photoreceptors (P. Galland and E.D. Lipson, 1985, Photochem. Photobiol. 41:331). In the two preceding papers, a kinetic model of the light-growth response system was developed and applied to wild-type frequency kernels at several wavelengths and temperatures. The present mutant studies were conducted at wavelength 477 nm. The log-mean intensity was 6 X 10(-2)W m-2 for the madB and madC night-blind mutants, and 10(-4)W m-2 for the madH hypertropic mutant. The prolonged light-growth responses of the madB and madC mutants are reflected in the reduced dynamic order of their frequency kernels. The linear response of the hypertropic mutant is essentially normal, but its nonlinear behavior shows modified dynamics. The behavior of these mutants can be accounted for by suitable modifications of the parametric model of the system. These modifications together support the hypothesis that an integrated complex mediates sensory transduction in the light responses and other responses of the sporangiophore.",

author = "A. Palit and P. Pratap and Lipson, {E. D.}",

note = "Funding Information: In view of the enhanced tropisms of this hypertropic mutant, one would expect its defect to be strictly in the growth control output of the sensory transduction chain for phototropism and the light-growth response. It is surpris- ing then that the hypertropic character also involves the photoreceptor input. One way to resolve this puzzle is to assume that there is not only a photoreceptor complex but rather there is an integrated sensory transduction complex that manages these photoresponses, as well as other responses such as gravitropism and avoidance. Compara- tive studies of single and double mutants by the white noise method (Poe et al., 1986a, b) provided independent evi- dence in support of this hypothesis. We thank Paul Galland and Benjamin Horwitz for valuable discussions and for critical reading of the manuscript and Craig Chmielwicz for technical assistance. This work was supported by grant GM29707 from the National Institutes of Health to Edward D. Lipson. Receivedfor publication 24 January 1986.",

year = "1986",

doi = "10.1016/S0006-3495(86)83506-8",

language = "English (US)",

volume = "50",

pages = "661--668",

journal = "Biophysical Journal",

issn = "0006-3495",

publisher = "Biophysical Society",

number = "4",

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TY - JOUR

T1 - System analysis of Phycomyces light-growth response. Photoreceptor and hypertropic mutants

AU - Palit, A.

AU - Pratap, P.

AU - Lipson, E. D.

N1 - Funding Information: In view of the enhanced tropisms of this hypertropic mutant, one would expect its defect to be strictly in the growth control output of the sensory transduction chain for phototropism and the light-growth response. It is surpris- ing then that the hypertropic character also involves the photoreceptor input. One way to resolve this puzzle is to assume that there is not only a photoreceptor complex but rather there is an integrated sensory transduction complex that manages these photoresponses, as well as other responses such as gravitropism and avoidance. Compara- tive studies of single and double mutants by the white noise method (Poe et al., 1986a, b) provided independent evi- dence in support of this hypothesis. We thank Paul Galland and Benjamin Horwitz for valuable discussions and for critical reading of the manuscript and Craig Chmielwicz for technical assistance. This work was supported by grant GM29707 from the National Institutes of Health to Edward D. Lipson. Receivedfor publication 24 January 1986.

PY - 1986

Y1 - 1986

N2 - The light-growth responses of Phycomyces behavioral mutants, defective in genes madB, madC, and madH, were studied with the sum-of-sinusoids method of system identification. Modified phototropic action spectra of these mutants have indicated that they have altered photoreceptors (P. Galland and E.D. Lipson, 1985, Photochem. Photobiol. 41:331). In the two preceding papers, a kinetic model of the light-growth response system was developed and applied to wild-type frequency kernels at several wavelengths and temperatures. The present mutant studies were conducted at wavelength 477 nm. The log-mean intensity was 6 X 10(-2)W m-2 for the madB and madC night-blind mutants, and 10(-4)W m-2 for the madH hypertropic mutant. The prolonged light-growth responses of the madB and madC mutants are reflected in the reduced dynamic order of their frequency kernels. The linear response of the hypertropic mutant is essentially normal, but its nonlinear behavior shows modified dynamics. The behavior of these mutants can be accounted for by suitable modifications of the parametric model of the system. These modifications together support the hypothesis that an integrated complex mediates sensory transduction in the light responses and other responses of the sporangiophore.

AB - The light-growth responses of Phycomyces behavioral mutants, defective in genes madB, madC, and madH, were studied with the sum-of-sinusoids method of system identification. Modified phototropic action spectra of these mutants have indicated that they have altered photoreceptors (P. Galland and E.D. Lipson, 1985, Photochem. Photobiol. 41:331). In the two preceding papers, a kinetic model of the light-growth response system was developed and applied to wild-type frequency kernels at several wavelengths and temperatures. The present mutant studies were conducted at wavelength 477 nm. The log-mean intensity was 6 X 10(-2)W m-2 for the madB and madC night-blind mutants, and 10(-4)W m-2 for the madH hypertropic mutant. The prolonged light-growth responses of the madB and madC mutants are reflected in the reduced dynamic order of their frequency kernels. The linear response of the hypertropic mutant is essentially normal, but its nonlinear behavior shows modified dynamics. The behavior of these mutants can be accounted for by suitable modifications of the parametric model of the system. These modifications together support the hypothesis that an integrated complex mediates sensory transduction in the light responses and other responses of the sporangiophore.

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EP - 668

JO - Biophysical Journal

JF - Biophysical Journal

IS - 4

ER -

System analysis of Phycomyces light-growth response. Photoreceptor and hypertropic mutants

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