scholarly journals Growth Conditions and Ripening Influence Plastid and Microsomal Membrane Lipid Composition in Bell Pepper Fruit

1991 ◽  
Vol 116 (3) ◽  
pp. 528-533 ◽  
Author(s):  
Bruce D. Whitaker
Keyword(s):  
Lipid Composition ◽  
Growth Conditions ◽  
Sterol Composition ◽  
Membrane Lipid ◽  
Bell Pepper ◽  
Membrane Lipid Composition ◽  
Pepper Fruit ◽  
Steryl Glycoside ◽  
Microsomal Membranes ◽  
Growing Conditions

Plastids and microsomal membranes were isolated from pericarp tissue of mature-green and red-ripe bell pepper (Capsicum annuum L.) fruit harvested from greenhouse- and field-grown plants. The lipid composition of these membrane fractions changed much more with ripening of field-grown than greenhouse-grown fruit. Also, the phospholipid (PL), free sterol (FS), steryl glycoside (SG), and acylated steryl glycoside (ASG) content of microsomes and plastids from green and red fruit were very different under the two growing conditions. Total steryl lipids (TSL = FS + SG + ASG) and the TSL: PL ratio increased in microsomes and decreased in plastids with ripening. These changes were much greater in field-grown fruit. The ASG: SG ratio decreased with ripening in both membrane fractions under both growing conditions. Ripening and growth conditions affected the phospholipid and sterol composition in plastids much more than in microsomes. Lipid changes associated with the chloroplast to chromoplast transformation were similar in field- and greenhouse-grown fruit, including an increase in the galactolipid: PL ratio.

scholarly journals EFFECTS OF GROWTH CONDITIONS AND RIPENING ON PLASTID AND MICROSOMAL MEMBRANE LIPID COMPOSITION IN BELL PEPPER FRUIT

HortScience ◽  
1990 ◽  
Vol 25 (9) ◽  
pp. 1080c-1080
Author(s):  
Bruce D. Whitaker
Keyword(s):  
Lipid Composition ◽  
Growth Conditions ◽  
Sterol Composition ◽  
Membrane Lipid ◽  
Membrane Lipid Composition ◽  
Future Studies ◽  
Pepper Fruit ◽  
Steryl Glycoside ◽  
Microsomal Membranes ◽  
Growing Conditions

Plastids and microsomal membranes were isolated from pericarp tissue of mature green and red-ripe tell pepper fruit harvested from greenhouse and field grown plants. The lipid composition of these membrane fractions changed far more with ripening of field grown than greenhouse grown fruit. Also, the phospholipid (PL), free sterol (FS), steryl glycoside (SG) and acylated steryl glycoside (ASG) content of microsomes and plastids from both green and red fruit were very different under the two growing conditions. Total steryl lipids (TSL = FS + SG + ASG), and the TSL/PL ratio, increased in microsomes and decreased in plastids with ripening. These changes were much greater in field grown fruit. The ASG/SG ratio decreased with ripening in both membrane fractions, under both growing conditions. Ripening and growth conditions affected the phospholipid and sterol composition in plastids much more than in microsomes. Lipid changes associated with the chloroplast – chromoplast transformation were similar in field and greenhouse grown fruit, including an increase in the galactolipid/PL ratio. Future studies will assess how differences in membrane lipid composition affect postharvest storage life of the fruit.

scholarly journals Effect of membrane environment on the activity and inhibitability by malonyl-CoA of the carnitine acyltransferase of hepatic microsomal membranes

1997 ◽  
Vol 322 (2) ◽  
pp. 435-440 ◽  
Author(s):  
Neil M. BROADWAY ◽  
E. David SAGGERSON
Keyword(s):  
Lipid Composition ◽  
Membrane Lipids ◽  
Specific Activity ◽  
Membrane Lipid ◽  
Microsomal Membrane ◽  
Membrane Lipid Composition ◽  
Carnitine Acyltransferase ◽  
Malonyl Coa ◽  
Microsomal Membranes ◽  
Myristoyl Coa

We have investigated the extent to which membrane environment affects the catalytic properties of the malonyl-CoA-sensitive carnitine acyltransferase of liver microsomal membranes. Arrhenius-type plots of activity were linear in the absence and presence of malonyl-CoA (2.5 μM). Sensitivity to malonyl-CoA increased with decreasing assay temperature. Partly purified enzyme displayed an increased K0.5 (substrate concentration supporting half the maximal reaction rate) for myristoyl-CoA and a reduced sensitivity to malonyl-CoA compared with the enzyme in situ in membranes. Reconstitution with liposomes of a range of compositions restored the K0.5 for myristoyl-CoA to values similar to that seen in native membranes. The lipid requirements for restoration of sensitivity to malonyl-CoA were more stringent. When animals were starved for 24 h the specific activity of carnitine acyltransferase in microsomal membrane residues was increased 3.3-fold, whereas sensitivity to malonyl-CoA was decreased to 1/2.8. When enzymes partly purified from fed and starved animals were reconstituted into crude soybean phosphatidylcholine liposomes there was no difference in sensitivity to malonyl-CoA. When partly purified enzyme from fed rats was reconstituted into liposomes prepared from microsomal membrane lipids from fed animals it was 2.2-fold more sensitive to malonyl-CoA than when reconstituted with liposomes prepared from microsomal membrane lipids from starved animals. This suggests that the physiological changes in sensitivity to malonyl-CoA are mediated via changes in membrane lipid composition rather than via modification of the enzyme protein itself. The increased specific actvity of acyltransferase observed on starvation could not be attributed to changes in membrane lipid composition.

Diurnal Variation in Membrane Lipid Composition of Sonoran Desert Teleosts

1989 ◽  
Vol 147 (1) ◽  
pp. 375-391 ◽  
Author(s):  
CYNTHIA CAREY ◽  
JEFFREY R. HAZEL
Keyword(s):  
Water Temperature ◽  
Molecular Species ◽  
Lipid Composition ◽  
Sonoran Desert ◽  
Plasma Membranes ◽  
Thermal Exposure ◽  
Membrane Lipid ◽  
Membrane Function ◽  
Membrane Lipid Composition ◽  
Microsomal Membranes

Phospholipid molecular species and headgroup compositions were determined for sarcoplasmic reticular and microsomal membranes in two species of Sonoran desert cyprinid fish (Agosia chrysogaster Girard and Notropis lutrensis Girard) trapped in an isolated pool of a desert stream. Fish populations were sampled in the cool of the morning (water temperature 21–21.9°C for Agosia and 22–26°C for Notropis) and 7–11 h later in the heat of the afternoon (water temperature 34.2°C) to determine whether membrane lipid composition varied with sampling time and thermal exposure. The composition of sarcoplasmic reticular membranes did not vary significantly through the day. In contrast, the molecular species composition of muscle microsomes (a mixture of endoplasmic reticulum and plasma membranes) changed markedly from the cool of the morning to the heat of the afternoon in both species. Adjustments were particularly striking in phosphatidylcholine (PC). For example, in Agosia, the ratio of saturated-to-unsaturated species of PC, the unsaturation index (the average number of double bonds per molecular species) and the proportion of diunsaturated molecular species deo- eased from 7.48 to 0.77, from 1.36 to 0.35 and from 7.23% to 2.46%, respectively, between the morning and afternoon samples. Similar, but less dramatic, changes were noted for phosphatidylethanolamine (PE) in both species, and for phosphatidylinositol (PI) in Notropis. In addition, microsomal membranes of Agosia exhibited a significant reduction in the proportion of PE (from 12.1 to 2.7%) and a corresponding increase in the proportion of PC between the morning and afternoon samples. These patterns of change in membrane lipid composition are in a direction consistent with thermal compensation of membrane function and suggest that rapid adjustments in the lipid composition of biological membranes may stabilize membrane structure against substantial diurnal fluctuations in temperature.

Methyl jasmonate alleviates chilling injury by regulating membrane lipid composition in green bell pepper

2020 ◽  
Vol 266 ◽  
pp. 109308
Author(s):  
Mingjie Ma ◽  
Zhiqiang Zhu ◽  
Shunchang Cheng ◽  
Qian Zhou ◽  
Xin Zhou ◽  
...  
Keyword(s):  
Methyl Jasmonate ◽  
Lipid Composition ◽  
Chilling Injury ◽  
Membrane Lipid ◽  
Bell Pepper ◽  
Membrane Lipid Composition

138 LIPID CHANGES IN TOMATO FRUIT MICROSOMAL MEMBRANES DURING RIPENING

HortScience ◽  
1994 ◽  
Vol 29 (5) ◽  
pp. 448d-448
Author(s):  
Bruce D. Whitaker
Keyword(s):  
Fatty Acid Composition ◽  
Fatty Acid ◽  
Physical Properties ◽  
Free Sterol ◽  
Tomato Fruit ◽  
Sterol Composition ◽  
Steryl Glycoside ◽  
Microsomal Membranes ◽  
Fruit Pericarp ◽  
Total Membrane

A previous study of lipids from pericarp tissue of tomato fruit ranging from mature-green to red-ripe showed a large increase in total sterols accompanied by dramatic changes in sterol composition and conjugation with ripening. This study was conducted to determine whether similar changes occur in microsomal membranes derived from tomato fruit pericarp. Acylated steryl glycoside (ASG), the predominant steryl lipid, declined during ripening, with increases in steryl glycoside (SG) and free sterol (FS). Only minor changes in fatty acid composition were associated with the drop in ASG. The stigmasterol:sitosterol ratio increased throughout ripening, but much more in Fs than in SG or ASG. The ratio of FS to phospholipid (PL) increased with ripening. However, FS was never greater than 10 percent of the total membrane sterol (TMS), and TMS:PL actually declined over the middle stages of ripening. It is not known why tomato tissues maintain such high levels of ASG and SG, but sterol conjugation is thought to regulate the physical properties of cell membranes.

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