The Influence of Cold Acclimation on the Lipid Composition and Cryobehaviour of the Plasma Membrane of Isolated Rye Protoplasts PDF Download

Author: P. L. Steponkus
Publisher:
ISBN:
Category : Cryobiology
Languages : en
Pages : 13

View

Book Description

Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 6

View

Book Description
Our aim is to provide a mechanistic understanding of the cellular and molecular aspects of freezing injury and cold acclimation from a perspective of the structural and functional integrity of the plasma membrane-the primary site of freezing injury in winter cereals. We established that destabilization of the plasma membrane of winter rye, the most freezing-tolerant winter cereal, can result from several different lesions: expansion induced lysis, lamellar-to-hexagonal II phase transitions, and the fracture-jump lesion. The occurrence and incidence of these various lesions, depends on the freeze/thaw protocol and the stage of cold acclimation. In non-acclimated leaves and protoplasts, expansion-induced lysis is the predominant lesion at temperatures between -2 and -5°C, whereas freeze-induced formation of the H{sub II} phase is the predominant lesion at temperatures below -10°C. We investigated whether the difference in freezing tolerance and the threshold temperatures at which the lesions occur in rye and oat are a consequence of differences in the lipid composition of the plasma membrane. There are substantial differences between rye and oat cell membranes both before and after cold acclimation. The plasma membrane of oat contains greater proportions of acylated sterylglucosides and cerebrosides than that of rye, and there is little change in these two lipid classes during cold acclimation. The lyotropic phase behavior of lipid mixtures that resemble the plasma membrane of rye and oat was studied. The differences in lipid composition of rye and oat are of mechanistic significance because of their influence on the hydration characteristics of the plasma membrane, the propensity for dehydration-induced lipid-lipid demixing, and the intrinsic curvature of the lipid monolayers. These studies suggest that strategies for improving the freezing tolerance of winter cereals should include approaches to modify membrane lipid composition.

Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 7

View

Book Description
Our goal is to provide a mechanistic understanding of the cellular and molecular aspects of freezing injury and cold acclimation from a perspective of the structural and functional integrity of the plasma membrane -- the primary site of freezing injury in winter cereals. We have utilized protoplasts isolated from leaves of winter rye (Secale cereale L. cv Puma) to study the cryobehavior of the plasma membrane during a freeze/thaw cycle. The focus of our current studies is on lesions in the plasma membrane that result from severe freeze-induced dehydration and result in the alteration of the semipermeable characteristics of the plasma membrane so that the protoplasts are osmotically unresponsive. In protoplasts isolated from non-acclimated rye leaves (NA protoplasts), injury is associated with the formation of aparticulate domains in the plasma membrane, aparticulate lamellae subtending the plasma membrane, and lamellar-to-hexagonal II phase transitions in the plasma membrane and the subtending lamellae. However, lamellar-to-hexagonal II phase transitions are not observed following severe dehydration of protoplasts isolated from cold-acclimated rye leaves (ACC protoplasts). Rather, injury is associated with the fracture-jump lesion, '' which, in freeze-fracture electron microscopy studies, is manifested as localized deviations in the fracture face of the plasma membrane. The fracture plane jumps'' from the plasma membrane to either subtending aparticulate lamellae or aparticulate regions of various endomembranes (predominantly chloroplast envelopes) that are in close apposition with the plasma membrane.

Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 7

View

Book Description
Our goal is to provide a mechanistic understanding of the cellular and molecular aspects of freezing injury and cold acclimation from a perspective of the structural and functional integrity of the plasma membrane -- the primary site of freezing injury in winter cereals. We have utilized protoplasts isolated from leaves of winter rye (Secale cereale L. cv Puma) to study the cryobehavior of the plasma membrane during a freeze/thaw cycle. The focus of our current studies is on lesions in the plasma membrane that result from severe freeze-induced dehydration and result in the alteration of the semipermeable characteristics of the plasma membrane so that the protoplasts are osmotically unresponsive. In protoplasts isolated from non-acclimated rye leaves (NA protoplasts), injury is associated with the formation of aparticulate domains in the plasma membrane, aparticulate lamellae subtending the plasma membrane, and lamellar-to-hexagonal II phase transitions in the plasma membrane and the subtending lamellae. However, lamellar-to-hexagonal II phase transitions are not observed following severe dehydration of protoplasts isolated from cold-acclimated rye leaves (ACC protoplasts). Rather, injury is associated with the fracture-jump lesion, '' which, in freeze-fracture electron microscopy studies, is manifested as localized deviations in the fracture face of the plasma membrane. The fracture plane jumps'' from the plasma membrane to either subtending aparticulate lamellae or aparticulate regions of various endomembranes (predominantly chloroplast envelopes) that are in close apposition with the plasma membrane.

Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 7

View

Book Description
Our goal is to provide a mechanistic understanding of the cellular and molecular aspects of freezing injury and cold acclimation from a perspective of the structural and functional integrity of the plasma membrane -- the primary site of freezing injury in winter cereals. We have utilized protoplasts isolated from leaves of winter rye (Secale cereale L. cv Puma) to study the cryobehavior of the plasma membrane during a freeze/thaw cycle. The focus of our current studies is on lesions in the plasma membrane that result from severe freeze-induced dehydration and result in the alteration of the semipermeable characteristics of the plasma membrane so that the protoplasts are osmotically unresponsive. In protoplasts isolated from non-acclimated rye leaves (NA protoplasts), injury is associated with the formation of aparticulate domains in the plasma membrane, aparticulate lamellae subtending the plasma membrane, and lamellar-to-hexagonal II phase transitions in the plasma membrane and the subtending lamellae. However, lamellar-to-hexagonal II phase transitions are not observed following severe dehydration of protoplasts isolated from cold-acclimated rye leaves (ACC protoplasts). Rather, injury is associated with the ''fracture-jump lesion, '' which, in freeze-fracture electron microscopy studies, is manifested as localized deviations in the fracture face of the plasma membrane. The fracture plane ''jumps'' from the plasma membrane to either subtending aparticulate lamellae or aparticulate regions of various endomembranes (predominantly chloroplast envelopes) that are in close apposition with the plasma membrane.

Author: William James Gordon-Kamm
Publisher:
ISBN:
Category : Cell membranes
Languages : en
Pages : 640

View

Book Description

Author: Rosa Margesin
Publisher: Springer Science & Business Media
ISBN: 3662062852
Category : Science
Languages : en
Pages : 408

View

Book Description
Representing the latest knowledge of the ecology and the physiology of cold-adapted microorganisms, plants and animals, this book explains the mechanisms of cold-adaptation on the enzymatic and molecular level, including results from the first crystal structures of enzymes of cold-adapted organisms.

Author: Paul H. Li
Publisher: Springer Science & Business Media
ISBN: 1489902775
Category : Science
Languages : en
Pages : 360

View

Book Description
This volume is compiled based on the proceedings of the 5th International Plant Cold Hardiness Seminar, which was held at Oregon State University, Corvallis, Oregon, USA, August 5 to 8, 1996. Participants representing 16 nations and 22 U. S. states attended the seminar. Researchers came from major laboratories around the world involving plant cold hardiness research. The information compiled in this volume represents the state-of the-art research and our understanding of plant cold hardiness in terms of molecular biol ogy, biochemistry, and physiology. The 1996 International Plant Cold Hardiness Seminar was the fifth of the series; it was first held in 1977 at the University of Minnesota, St. Paul, MN, and since then has met every 5 years. The overall goal of this seminar series is to foster the exchange of ideas and research findings among the diverse groups of scientists studying freezing and chilling stresses from a wide variety of perspectives. This is the only international conference focus ing its programs entirely on low temperature stress in plants. In accordance with the tradi tion, the fifth conference focused on freezing and chilling stress of plants and covered various aspects of plant cold hardiness, including molecular genetics, biochemistry, physi ology, and agricultural applications. All contributors to this volume are eminent researchers who have had significant contributions to the knowledge of plant cold hardiness.

Author: E. Anibal Disalvo
Publisher: CRC Press
ISBN: 1351425390
Category : Science
Languages : en
Pages : 288

View

Book Description
This book presents a comprehensive and coherent picture of how molecules diffuse across a liquid that is, on average, only two molecules thick. It begins by characterizing bilayers structurally, using X-ray diffraction, and then mechanically by measuring elastic moduli and mechanisms of failure. Emphasis is placed on the stability and mechanical properties of plant membranes that are subject to very large osmotic and thermal stresses. Using this information, the transport of molecules of increasing complexity across bilayers is analyzed.

Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 12

View

Book Description
This project focuses on lesions in the plasma membrane of protoplasts that occur during freezing to temperatures below -5° which result in changes in the semipermeablity of the plasma membrane. This injury, referred to as loss of osmotic responsiveness, is associated with the formation of large, aparticulate domains in the plasma membrane, aparticulate lamellae subtending the plasma membrane, and lamellar-to-hexagonal{sub II} phase transitions in the plasma membrane and subtending lamellar. The goals of this project are to provide a mechanistic understanding of the mechanism by which freeze-induced dehydration effects the formation of aparticulate domains and lamellar-to-hexagonal{sub II} phase transitions and to determine the mechanisms by which cold acclimation and cryoprotectants preclude or diminish these ultrastructural changes. Our working hypothesis is the formation of aparticulate domains and lamellar-to-hexagon{sub II} phase transitions in the plasma membrane and subtending lamellae are manifestations of hydration-dependent bilayer-bilayer interactions.