scholarly journals Polar lipids are linked to nanoparticles in xylem sap of temperate angiosperm species

2021 ◽  
Author(s):  
Xinyi Guan ◽  
H Jochen Schenk ◽  
Mary R. Roth ◽  
Ruth Welti ◽  
Julia Werner ◽  
...  

Xylem sap of angiosperm species has been found to include low concentrations of polar lipids and nanoparticles, including surfactant-coated nanobubbles. Although the nanoparticles have been suggested to consist of polar lipids, no attempt has been made to determine if nanoparticle and lipid concentrations are related. Here, we examined concentrations of nanoparticles and lipids in xylem sap and contamination control samples of six temperate angiosperm species with a NanoSight device and based on mass spectrometry. We found (1) that the concentration of nanoparticles and lipids were both diluted when an increasing amount of sap was extracted, (2) that their concentrations were significantly correlated in three species, (3) that their concentrations were affected by vessel anatomy, and (4) that concentrations of nanoparticles and lipids were very low in contamination-control samples. Moreover, there was little seasonal difference, no freezing-thawing effect on nanoparticles, and little seasonal variation in lipid composition. These findings indicate that lipids and nanoparticles are related to each other, and largely do not pass interconduit pit membranes. Further research is needed to examine the formation and stability of nanoparticles in xylem sap in relation to lipid composition, and the complicated interactions among the gas, liquid, and solid phases in xylem conduits.

2019 ◽  
Author(s):  
H. Jochen Schenk ◽  
Joseph M. Michaud ◽  
Kerri Mocko ◽  
Susana Espino ◽  
Tatiana Melendres ◽  
...  

AbstractLipids have been observed attached to lumen-facing surfaces of mature xylem conduits of several plant species, but there has been little research on their functions or effects on water transport, and only one lipidomic study of the xylem apoplast. Therefore, we conducted lipidomic analyses of xylem sap from woody stems of seven plants representing six major angiosperm clades, including basal magnoliids, monocots, and eudicots, to characterize and quantify phospholipids, galactolipids, and sulfolipids in sap using mass spectrometry. Locations of lipids in vessels of Laurus nobilis were imaged using TEM and confocal microscopy. Xylem sap contained the galactolipids di- and mono-galactosyldiacylglycerol (DGDG and MGDG), as well as all common plant phospholipids, but only traces of sulfolipids, with total lipid concentrations in extracted sap ranging from 0.18 to 0.63 nmol / mL across all seven species. Contamination of extracted sap from lipids in cut living cells was found to be negligible. Lipid composition of sap was compared to wood in two species and was largely similar, suggesting that sap lipids, including galactolipids, originate from cell content of living vessels. Seasonal changes in lipid composition of sap were observed for one species. Lipid layers coated all lumen-facing vessel surfaces of Laurus nobilis, and lipids were highly concentrated in inter-vessel pits. The findings suggest that apoplastic, amphiphilic xylem lipids are a universal feature of angiosperms. The findings require a reinterpretation of the cohesion-tension theory of water transport to account for the effects of apoplastic lipids on dynamic surface tension and hydraulic conductance in xylem.


2005 ◽  
Vol 68 (9) ◽  
pp. 1895-1899 ◽  
Author(s):  
MANOJ KUMAR MOHAN NAIR ◽  
HANEM ABOUELEZZ ◽  
THOMAS HOAGLAND ◽  
KUMAR VENKITANARAYANAN

The antibacterial effect of low concentrations of monocaprylin on Escherichia coli O157:H7 in apple juice was investigated. Apple juice alone (control) or containing 2.5 mM (0.055%) or 5 mM monocaprylin was inoculated with a five-strain mixture of E. coli O157:H7 at ~6.0 log CFU/ml. The juice samples were stored at 23 or 4°C for 14 or 21 days, respectively, and the population of E. coli O157:H7 was determined on tryptic soy agar plates supplemented with 0.6% yeast extract. At both storage temperatures, the population of E. coli O157:H7 in monocaprylin-supplemented juice samples was significantly lower (P < 0.05) than that in the control samples. The concentration of monocaprylin and the storage temperature had a significant effect on the inactivation of E. coli O157:H7 in apple juice. Monocaprylin at 5 mM was significantly more effective than 2.5 mM monocaprylin for killing E. coli O157:H7 in apple juice. Inactivation of E. coli O157:H7 by monocaprylin was more pronounced in juice stored at 23°C than in the refrigerated samples. Results of this study indicated that monocaprylin is effective for killing E. coli O157:H7 in apple juice, but detailed sensory studies are needed to determine the organoleptic properties of apple juice containing monocaprylin.


2017 ◽  
Vol 4 ◽  
pp. e004 ◽  
Author(s):  
Christine Scoffoni ◽  
Grace John ◽  
Herve Cochard ◽  
Lawren Sack

Replacing ultra-pure water solution with ion solution closer to the composition of natural xylem sap increases stem hydraulic conductance by up to 58%, likely due to changes in electroviscosity in the pit membrane pores. This effect has been proposed to contribute to the control of plant hydraulic and stomatal conductance and potentially to influence on carbon balance during dehydration. However, this effect has never been directly tested for leaf xylem, which constitutes a major bottleneck in the whole plant. We tested for an ion-mediated increase in the hydraulic conductance of the leaf xylem (Kx) for seven species diverse in phylogeny and drought tolerance. Across species, no significant changes in Kx were observed between 0 and 15 mM KCl. We further tested for an effect of ion solution during measurements of Kx vulnerability to dehydration in Quercus agrifolia and found no significant impact. These results for leaf xylem contrast with the often strong ion effect reported for stems, and we suggest several hypotheses to account for the difference, relating to the structure of xylem conduits across vein orders, and the ultrastructure of leaf xylem pores. A negligible ion response in leaves would weaken xylem sap ion-mediated control of plant hydraulic conductance, facilitating modeling of whole plant hydraulic behavior and its influence on productivity.


1968 ◽  
Vol 109 (1) ◽  
pp. 51-59 ◽  
Author(s):  
G. G. Forstner ◽  
K. Tanaka ◽  
K. J. Isselbacher

1. Rat intestinal microvillus plasma membranes were prepared from previously isolated brush borders and the lipid composition was analysed. 2. The molar ratio of cholesterol to phospholipid was greatest in the membranes and closely resembled that reported for myelin. 3. Unesterified cholesterol was the major neutral lipid. However, 30% of the neutral lipid fraction was accounted for by glycerides and fatty acid. 4. Five phospholipid components were identified and measured, including phosphatidylethanolamine, phosphatidylcholine, phosphatidylserine, sphingomyelin and lysophosphatidylcholine. Though phosphatidylethanolamine was the chief phospholipid, no plasmalogen was detected. 5. In contrast with other plasma membranes in the rat, the polar lipids of the microvillus membrane were rich in glycolipid. The cholesterol:polar lipid (phospholipid+glycolipid) ratio was about 1:3 for the microvillus membrane. Published data suggest that this ratio resembles that of the liver plasma membrane more closely than myelin or the erythrocyte membrane. 6. The fatty acid composition of membrane lipids was altered markedly by a single feeding of safflower oil. Membrane polar lipids did not contain significantly more saturated fatty acids than cellular polar lipids. Differences in the proportion of some fatty acids in membrane and cellular glycerides were noted. These differences may reflect the presence of specific membrane glycerides.


1963 ◽  
Vol 41 (6) ◽  
pp. 939-946 ◽  
Author(s):  
M. I. Naguib

The effects of chlorobenzoic acids on respiration, sucrose absorption, and carbohydrate metabolism of etiolated barley leaves were studied. The results showed that respiration was retarded to the same extent irrespective of position of substitution, in the presence of these substances; inhibition was more pronounced at higher concentrations of chlorobenzoic acids. At low concentrations, o-chlorobenzoic acid enhanced sucrose uptake and p-chlorobenzoic inhibited uptake while at higher concentrations, both compounds inhibited sucrose uptake by etiolated barley leaves.Tissue analysis for carbohydrates showed a decrease in all carbohydrate fractions of treated leaves compared to the control samples. Even the sucrose-fed treated samples showed a carbohydrate content similar to that of the samples starving in distilled water in spite of the variable amounts of sugars absorbed by such samples.These observations, together with excretion of some copper-reducing substances that disappeared after clearing, support the previous suggestion (4) that the tissue carbohydrates were mostly transformed to non-sugar substances that might have been excreted as a result of increased permeability in the presence of the chlorobenzoic acids. This suggestion, together with the possibility of deactivation of the respiratory dehydrogenases, may explain the reduced rates of respiration of the treated samples.


1970 ◽  
Vol 119 (5) ◽  
pp. 861-869 ◽  
Author(s):  
Margaret A. C. Bermingham ◽  
B. S. Deol ◽  
J. L. Still

The addition of low concentrations of streptomycin (5–10μg/ml of medium) to Serratia marcescens caused significant alterations in the lipid composition of this organism, but neither growth nor pigmentation was affected. The acetone-soluble cyclic depsipeptides, which comprise on average 15% of the total lipid, were decreased almost to zero and the total lipid phosphorus was more than doubled in the presence of streptomycin. Most of the phospholipid increase was due to an increase in phosphatidylethanolamine. Cyclic depsipeptides were not leached from the cell in the presence of streptomycin, indicating a definite inhibition of the biosynthetic pathway. The effect of streptomycin on the reported peptidolipids of Rhodopseudomonas spheroides, Halobacterium halobium, Nocardia asteroides and Pseudomonas tabaci was investigated. In the case of the only strictly comparable cellular cyclic depsipeptide (that of N. asteroides) the biosynthesis was strongly inhibited by streptomycin, but cell weight was maintained or even slightly increased. A possible mode and site of action of low concentrations of streptomycin on bacterial lipids is discussed.


1973 ◽  
Vol 28 (1-2) ◽  
pp. 90-93 ◽  
Author(s):  
H. Diringers ◽  
H.-P. Kulas ◽  
L. G. Schneider ◽  
H. D. Schlumberger

The lipid composition of the Flury HEP strain of rabies virus grown in BHK 21/C 13 cells was determined. The dried purified virus preparation contains 5.5 % neutral and 19.5 % polar lipids. Cholesterol was found to be the major neutral lipid. Phopholipids constitute 11.2 %; and glycolipids represent 4.6 % of the virus mass. The residual 3.7 % of extracted polar lipid material could not be accounted for by any known lipids. Phosphatidylethanolamine, phosphatidylcholine and sphingomyelin are the main constituents of the viral phospholipids. Hema- toside is the only ganglioside and the main glycolipid present in the virus. The glycolipids of the host cell and the virus are identical. The molar ratio of sphingolipids to glycerophospho-lipids is 0.8.


2021 ◽  
Author(s):  
Karl H. Kasper ◽  
Ilka N Abreu ◽  
Kirstin Feussner ◽  
Krzysztof Zienkiewicz ◽  
Cornelia Herrfurth ◽  
...  

Xylem sap is the major transport route for nutrients from roots to shoots. Here, we investigated how variations in nitrogen (N) nutrition affected the metabolome and proteome of xylem sap, growth of the xylem endophyte Brennaria salicis and report transcriptional re-wiring of leaf defenses in poplar (Populus x canescens). We supplied poplars with high, intermediate or low concentrations of ammonium or nitrate. We identified 288 unique proteins in xylem sap. About 85% of the xylem sap proteins were shared among ammonium- and nitrate-supplied plants. The number of proteins increased with increasing N supply but the major functional categories (catabolic processes, cell wall-related enzymes, defense) were unaffected. Ammonium nutrition caused higher abundances of amino acids and carbohydrates, while nitrate caused higher malate levels in xylem sap. Pipecolic acid and N-hydroxy-pipecolic acid increased whereas salicylic acid and jasmonoyl-isoleucine decreased with increasing N nutrition. Untargeted metabolome analyses revealed 2179 features in xylem sap, of which 863 were differentially affected by N treatments. We identified 122 metabolites, mainly from specialized metabolism of the groups of salicinoids, phenylpropanoids, phenolics, flavonoids, and benzoates. Their abundances increased with decreasing N. Endophyte growth was stimulated in xylem sap of high N- and suppressed in that of low N-fed plants. The drastic changes in xylem sap composition caused massive changes in the transcriptional landscape of leaves and recruited defense pathways against leaf feeding insects and biotrophic fungi, mainly under low nitrate. Our study uncovers unexpected complexity and variability of xylem composition with consequences for plant defenses.


Lipids ◽  
2015 ◽  
Vol 50 (6) ◽  
pp. 605-610 ◽  
Author(s):  
Paula M. Miotto ◽  
Laura M. Castelli ◽  
Foyinsola Amoye ◽  
Wendy E. Ward ◽  
Paul J. LeBlanc

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