Homeoviscous Adaptation in Psychrophilic, Meosphilic and Thermophilic Yeasts

1980 ◽  
pp. 349-363 ◽  
Author(s):  
Kenneth Watson
Keyword(s):  
Homeoviscous Adaptation

Temperature-induced homeoviscous adaptation of chinese hamster ovary cells

1981 ◽  
Vol 641 (2) ◽  
pp. 334-348 ◽  
Author(s):  
Robin L. Anderson ◽  
Kenneth W. Minton ◽  
Gloria C. Li ◽  
George M. Hahn
Keyword(s):  
Chinese Hamster Ovary ◽  
Chinese Hamster Ovary Cells ◽  
Chinese Hamster ◽  
Homeoviscous Adaptation ◽  
Ovary Cells

Membrane Lipids and Maximum Lifespan in Clownfish

2021 ◽  
Author(s):  
PEDRO FRANCISCO ALMAIDA PAGÁN ◽  
Alejandro Lucas-Sanchez ◽  
Antonio Martinez-Nicolas ◽  
Eva Terzibasi ◽  
Maria Angeles Rol de Lama ◽  
...  
Keyword(s):  
Lipid Composition ◽  
Potential Model ◽  
Membrane Lipids ◽  
Membrane Lipid ◽  
Maximum Lifespan ◽  
Homeoviscous Adaptation ◽  
Theory Of Aging ◽  
Peroxidation Index ◽  
Membrane Peroxidation ◽  
Contradictory Data

Abstract The longevity-homeoviscous adaptation (LHA) theory of aging states that lipid composition of cell membranes is linked to metabolic rate and lifespan, which has been widely shown in mammals and birds but not sufficiently in fish. In this study, two species of the genus Amphiprion (A. percula and A. clarkii, with estimated maximum lifespan potentials [MLSP] of 30 and 9-16 years, respectively) and the damselfish Chromis viridis (estimated MLSP of 1-2 years) were chosen to test the LHA theory of aging in a potential model of exceptional longevity. Brain, livers and samples of skeletal muscle were collected for lipid analyses and integral part in the computation of membrane peroxidation indexes (PIn) from phospholipid (PL) fractions and PL fatty acid composition. When only the two anemonefish were compared, results pointed to the existence of a negative correlation between membrane PIn value and maximum life expectancy, well in line with the predictions from the LHA theory of aging. Nevertheless, contradictory data were obtained when the two clownfish were compared to the shorter-lived C. viridis. This results along with those obtained in previous studies on fish denote that the magnitude (and sometimes the direction) of the differences observed in membrane lipid composition and peroxidation index with MLSP cannot explain alone the diversity in longevity found among fishes.

Ontogeny of the capacity for homeoviscous adaptation in white sturgeon (Acipenser transmontanus)

1993 ◽  
Vol 265 (1) ◽  
pp. 18-28 ◽  
Author(s):  
Randal K. Buddington ◽  
Jeffrey R. Hazel ◽  
Serge I. Doroshov ◽  
Joel Van Eenennaam
Keyword(s):  
White Sturgeon ◽  
Acipenser Transmontanus ◽  
Homeoviscous Adaptation

scholarly journals The Outer Surface Lipoprotein VolA Mediates Utilization of Exogenous Lipids by Vibrio cholerae

mBio ◽  
2013 ◽  
Vol 4 (3) ◽  
Author(s):  
Aaron C. Pride ◽  
Carmen M. Herrera ◽  
Ziqiang Guan ◽  
David K. Giles ◽  
M. Stephen Trent
Keyword(s):  
Fatty Acids ◽  
Fatty Acid ◽  
Carbon Source ◽  
Outer Membrane ◽  
Vibrio Cholerae ◽  
Homeoviscous Adaptation ◽  
Gram Negative ◽  
Content Type ◽  
Enzymatic Function ◽  
Gram Negative Organisms

ABSTRACTPrevious work from our laboratory showed that the Gram-negative aquatic pathogenVibrio choleraecan take up a much wider repertoire of fatty acids than other Gram-negative organisms. The current work elaborated on the ability ofV. choleraeto exploit an even more diverse pool of lipid nutrients from its environment. We have demonstrated that the bacterium can use lysophosphatidylcholine as a metabolite for growth. Using a combination of thin-layer chromatography and mass spectrometry, we also showed that lysophosphatidylcholine-derived fatty acid moieties can be used for remodeling theV. choleraemembrane architecture. Furthermore, we have identified a lysophospholipase, VolA (Vibrioouter membrane lysophospholipase A), required for these activities. The enzyme is well conserved inVibriospecies, is coexpressed with the outer membrane fatty acid transporter FadL, is one of very few surface-exposed lipoprotein enzymes to be identified in Gram-negative bacteria and the first instance of a surface lipoprotein phospholipase. We propose a model whereby the bacterium efficiently couples the liberation of fatty acid from lysophosphatidylcholine to its subsequent metabolic uptake. An expanded ability to scavenge diverse environmental lipids at the bacterial surface increases overall bacterial fitness and promotes homeoviscous adaptation through membrane remodeling.IMPORTANCEOur understanding of how bacteria utilize environmental lipid sources has been limited to lipids such as fatty acids and cholesterol. This narrow scope may be attributed to both the intricate nature of lipid uptake mechanisms and the diversity of lipid substrates encountered within an ecological niche. By examining the ability of the pathogenVibrio choleraeto utilize exogenous lipids, we uncovered a surface-exposed lipoprotein (VolA) that is required for processing the prevalent host lipid lysophosphatidylcholine. VolA functions as a lipase liberating a fatty acid from exogenous lysophospholipids. The freed fatty acid is then transported into the cell, serving as a carbon source, or shunted into phospholipid synthesis for membrane assembly. A limited number of surface-exposed lipoproteins have been found in Gram-negative organisms, and few have enzymatic function. This work highlights the ability of bacteria to exploit exogenous lipids for both maintenance of the membrane and carbon source acquisition.

Homeoviscous adaptation and thermal compensation of sodium pump of trout erythrocytes

1991 ◽  
Vol 260 (5) ◽  
pp. R916-R924 ◽  
Author(s):  
R. S. Raynard ◽  
A. R. Cossins
Keyword(s):  
Cold Acclimation ◽  
Scatchard Analysis ◽  
Transport Activity ◽  
Turnover Number ◽  
Ouabain Binding ◽  
Homeoviscous Adaptation ◽  
Membrane Order ◽  
Na Pump ◽  
Pump Activity ◽  
Cholesterol Supplementation

The effects of thermal acclimation of trout on the transport activity and turnover number of the erythrocyte Na+ pump have been determined. Na+ pump activity was estimated by measuring the ouabain-sensitive K+ influx in Na(+)-loaded cells and the number of active pumps determined by Scatchard analysis of [3H]ouabain binding and by correlation of ouabain binding with pump inhibition. Cold acclimation was associated with an increase in pump activity of up to 60%, although the furosemide-sensitive and residual fluxes were unaffected. The number of ouabain binding sites was similar in both acclimation groups at approximately 21,000-23,000 sites/cell. This means that cold acclimation induced an increase in the transport turnover number of pump molecules from approximately 6 to 9 s-1. Cold acclimation was also associated with a decrease in membrane order as indicated by steady-state fluorescence polarization of the membrane probe, 1,3-diphenyl-1,3,5-hexatriene, with a homeoviscous efficacy of 25-41%. That membrane order may influence pump transport activity is supported by experiments on cholesterol supplementation, which caused both an increase in membrane order and a decrease in pump turnover number. The degree of pump compensation was dependent on the season, with greatest responses in the late spring and declining responses through to winter. By contrast, changes in membrane order were observed throughout the year. Expression of pump activity and erythropoiesis may vary throughout the seasonal cycle in complex ways that confuse the direct comparison study of cellular properties in a heterogeneous population of cells.

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