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Hillbrick, Gordon Colin, and kimg@deakin edu au. "THE LIPID COMPOSITION OF CASHMERE GOAT FIBRES." Deakin University, 1994. http://tux.lib.deakin.edu.au./adt-VDU/public/adt-VDU20031205.162817.
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This study examined the differences in the chemical composition, particularly fatty acids, of the lipid extracted from the fibre of bucks, does and castrated goats. The study provides a more detailed understanding of the chemical composition of buck fibre lipid and how it varies throughout the year, and also details the effect of body region and nutrition on the production and chemical composition of lipid from buck fibre.
Lipid was extracted with either petroleum ether (non-polar) or chloroform/methanol azeotrope (polar) and analysed by gas chromatography and gas chromatography-mass spectrometry. The more polar solvent system extracted larger amounts of lipid and more of each individual fatty acid. The following buck specific ethyl branched fatty acids were identified: 2-ethylhexanoic, 4-ethylhexanoic, 2-ethyloctanoic, 4-ethyloctanoic, 6-ethyloctanoic, 2-ethyldecanoic, 4-ethyldecanoic, 2-ethyldodecanoic, 6-ethyldodecanoic, 4-ethyldodecanoic, 2-ethyltetradecanoic, 6-ethyltetradecanoic, 4-ethyltetradecanoic, 2-ethylhexadecanoic and 4-ethyloctadecanoic acids. Of these buck specific fatty acids only 4-ethylhexanoic (T), 4-ethyloctanoic, 4-ethyldecanoic, 4-ethyldodecanoic, 6-ethyldodecanoic (T), 4-ethyltetradecanoic, 2-ethylhexadecanoic (T) and 4-ethylhexadecanoic acids have been previously identified or tentatively identified (T) in buck fibre extracts. This shows that the chemical composition of buck fibre lipid is more complex than previously reported, and that it may be more difficult than previously thought to artificially duplicate the odour of the buck.
Buck fibre samples had lower average
concentrations of 2-methylpropanoic, 2-methylbutanoic, iso-pentadecanoic, anteiso-pentadecanoic, iso-hexadecanoic, anteiso-heptadecanoic, iso-octadecanoic and anteiso-nonadecanoic acids as compared with fibre samples from does, spayed does, or wethers that were castrated at one month of age. The reduced concentrations of these fatty acids in buck fibre extracts were likely to be due to the synthesis of ethyl branched derivatives of iso and anteiso fatty acids. Buck fibre samples had higher concentrations of benzoic acid as compared with fibre samples from does, spayed does, or wethers that were castrated at one month of age. The significance of these results is that non buck specific fatty acids may also make a contribution to the odour of bucks.
When fibre samples were collected at various times throughout the year, it was found that the bucks had increased amounts of lipid and ethyl branched fatty acids in fibre samples shorn from March to September, as compared with fibre samples shorn in November and January. The increase in the amount of lipid and ethyl branched fatty acids corresponded with both the rutting period of the buck and the period when the buck odour was increased. This suggests that ethyl branched fatty acids could be pheromones.
The variation in lipid content and fatty acid composition was also examined between fibre samples collected from different body regions of the buck during April, as alterations in sebaceous gland activity around the neck during rutting have been reported. It was found that the average amount of lipid in the neck region of the bucks was not statistically higher than the average amounts in the midside and hind regions. However, the ethyl branched fatty acid concentrations were statistically higher in the fibre from around the neck as compared with the fibre from the other body regions, which is consistent with the odour of the buck being most pronounced around the head and neck region.
The lipid content and composition of fibre samples from bucks fed high and low quality diets (lucerne and pangola grass, respectively) was examined to determine the effect of nutrition on buck specific components. The high quality diet increased the amount of lipid and ethyl branched fatty acids in fibre samples collected in April from the neck, midside and hind regions, as compared with fibre samples from the corresponding body regions from bucks fed the low quality diet. Thus it may be possible for the pheromone levels of bucks to be increased by simply providing them with good nutrition.
The lipid content and ethyl branched fatty acid concentrations of fibre samples increased earlier in the year for the lucerne fed bucks as compared with the pangola grass fed bucks. The lucerne fed bucks had increased concentrations of ethyl branched fatty acids in fibre samples shorn during December to June (6 months) whereas the pangola grass fed bucks had increased concentrations of ethyl branched fatty acids in fibre samples shorn during April to August (4 months). These observations show that good nutrition can result in both the earlier production of ethyl branched fatty acids and an extended period when ethyl branched fatty acids are produced. This suggests that nutrition can be used to manipulate pheromone levels in the buck. The period when the ethyl branched fatty acids were increased corresponded with the period when the plasma luteinizing hormone (LH) and testosterone concentrations, odour and sebaceous gland volume of the bucks were increased, which supports the assumption that ethyl branched fatty acids are involved in odour production and act as pheromones.
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Fischer, Carol Lea. "Oral mucosal lipids are antimicrobial against Porphyromonas gingivalis, induce ultrastructural damage, and alter bacterial lipid and protein compositions." Diss., University of Iowa, 2013. https://ir.uiowa.edu/etd/2494.
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Periodontal disease is a chronic inflammation of the gingiva and periodontium that leads to progressive destruction and irreversible damage to the supportive structures of the teeth. It affects nearly half of the United States population and is a particular risk factor in adults older than 65 years of age. Oral microorganisms assemble in plaque as a polymicrobial biofilm and Porphyromonas gingivalis, an important secondary colonizer in oral biofilms, has been implicated in periodontal disease. Although the protective functions of various salivary molecules such as antimicrobial proteins have been delineated, lipids present in saliva and on the oral mucosa have been largely ignored and there is growing evidence that the role of lipids in innate immunity is more important than previously realized. In fact, recent studies suggest that sphingoid bases and fatty acids, which exhibit potent broad spectrum antimicrobial activity against a variety of bacteria and fungi, are likely important innate immune molecules involved in the defense against oral bacterial and fungal infections. However little is known about their spectrum of activity or mechanisms of action. In addition, the effects of these lipids that are endogenous to the oral cavity have not been explored against oral bacteria. In this study I hypothesized that oral mucosal and salivary lipids exhibit dose-dependent antimicrobial activity against P. gingivalis and alter cell morphology and metabolic events. To test this hypothesis, I first examined the effects of two fatty acids: sapienic acid and lauric acid, and three sphingoid bases: sphingosine, dihydrosphingosine, and phytosphingosine, against a variety of gram-positive and gram-negative bacteria including P. gingivalis. Using broth microdilution assays to determine minimum inhibitory and minimum bactericidal concentrations, I show that antimicrobial activity against bacteria is dose-dependent, lipid specific, and microorganism specific. Kill kinetics were also variable across each bacteria-lipid combination. Upon examination of select bacteria-lipid combinations via scanning and transmission electron microscopy, different morphologies were evident across all treatments, demonstrating differential activity of each lipid for a particular bacterium as well as for each bacterium across different lipids. In addition, all sphingoid bases and fatty acids were taken up and retained in association with P. gingivalis cells and could be extracted along with bacterial lipids and separated using thin layer chromatography. Using a combination of two-dimensional in-gel electrophoresis and Western blots followed by mass spectroscopy and n-terminus degradation sequencing, I show that sapienic-acid treatment induces a unique stress response in P. gingivalis, as evidenced by the ability of P. gingivalis to upregulate a set of proteins involved in fatty acid biosynthesis metabolism and energy production, protein processing, cell adhesion, and virulence. Finally, utilizing flow cytometry and confocal microscopy, I assessed the effects of oral antimicrobial lipids against a representative host cell and describe oral lipid concentrations that are both antimicrobial to P. gingivalis cells and non-cytotoxic to the representative host cells tested. Combined, these data strongly suggest that sphingoid bases and fatty acids found within the saliva and on oral mucosa likely do contribute to the innate antimicrobial activity of saliva, mucosal surfaces, and skin and this dose-dependent activity is both lipid specific and bacteria specific. This information adds to current knowledge of the innate functions of endogenous lipids in the oral cavity. With bacterial resistance to current antibiotics increasing, the exploration of new antimicrobial agents is important and these lipid treatments may be beneficial for prophylactic treatments or therapeutic intervention of infection by supplementing the natural immune function of endogenous lipids on skin and other mucosal membranes.
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Jahan, Kishowar. "Quality in organic, free-range and conventional chicken breasts related to lipid antioxidant compositions." Thesis, University of Strathclyde, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.417332.
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Shah, Siddharth Prakashchandra. "LIPID COMPOSITIONS OF MICROBIAL ORGANISMS ISOLATED FROM EXTREME ENVIRONMENTS AND THEIR IMPLICATION IN THERMO STABILITY OF BACTERIAL CELL MEMBRANE STRUCTURE." Diss., Temple University Libraries, 2016. http://cdm16002.contentdm.oclc.org/cdm/ref/collection/p245801coll10/id/419298.
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ChemistryPh.D.
Microorganisms with an ability to thrive in harsh environments are referred as “extremophiles”. With advances in biotechnology, interest has grown in the extremophile research because of their unique macromolecules’ characteristics due to their growth environments. Over last decade, researchers have isolated many extremophiles from environments like volcano, salt lakes, hydrothermal vents, deep oceans, Antarctica glaciers etc. Macromolecules of these extremophiles are responsible for their survival in extreme environments. In this research work we have isolated lipid molecules from three different microorganisms. 1) GWE1 strain, a thermophilic bacterium, isolated from dark crusty material from sterilization ovens. 2) 7L strain, a thermophilic bacterium, isolated from Chilean Copahue Volcano. 3) I1P strain, a facultative anaerobe of the family Enterobacteriaceae, recently isolated from Antarctica. Complex lipid arrangement and/or type in the cell membrane are known to affect thermostability of microorganisms and efforts were made to understand the chemical nature of the polar lipids of membrane. In this work, we extracted total lipids from cell membrane, separated them by TLC into various fractions and characterize the lipid structures of fractions with analytical tools such as 1H, 13C, 31P and 2D NMR spectroscopy, ATR-FTIR spectroscopy and MSn spectrometry. In GWE1 strain, we were able to identify glycerophosphoethanolamine, glycerophosphate, glycerophosphoglycerol and cardiolipin lipid classes and an unknown glycerophospholipid class with novel MS/MS spectra pattern. We have also noticed the presence of saturated iso-branched fatty acids with NMR spectra in individual lipid classes. In case of I1P strain, we have identified glycerophosphoglycerol, glycerophosphoethanolamine, glycerophosphate, and acyl glycerophosphoglycerol lipid classes with unsaturated fatty acids in their structure, which could be one of the many reasons for survivability at lower temperatures. In case of 7L strain, we were able to identify glycerophosphoglycerol, cardiolipin, glycerophosphoethanolamine and glycerophosphate lipid classes with saturated iso branched fatty acids. FAME analysis revealed iso-15:0 (52.29 %) and iso-17:0 (18.64 %) as major fatty acyl chains. We did not observe major difference in polar head group composition of lipid classes between thermophiles (GWE1 and 7L) compare to psychrophiles (I1P). Major difference among these three strains was in fatty acid composition of lipid molecule. Both thermophiles showed presence of lipids with long chain saturated fatty acids while I1P showed presence of lipid molecule with unsaturated fatty acid chain. Lipids made of unsaturated fatty acids have lower melting points and they introduce kink in the cell membrane structure. At lower temperatures, these effects allow membrane to maintain fluidity and its functionality, which in turn allows the microorganism to grow at lower temperature. Lipids made with saturated iso branched fatty acid chain have higher melting points and they pack together densely in cell membrane. At high temperature because of higher melting point and dense packing, membrane fluidity is not affected and this effect allows microorganism to grow at the higher temperature. We believe that change in fatty acid composition is one of the many reasons for these microorganisms to survive the extreme condition. Thermostability of the other macromolecules (DNA, enzyme) of these extremophiles is not studied in this dissertation.
Temple University--Theses
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鄺懿珩 and Yi-hang Agnes Kwong. "Lipid composition and lipases of Angiostrongylus cantonensis (nematoda: metastrongyloidea)." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 1989. http://hub.hku.hk/bib/B31209208.
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Kwong, Yi-hang Agnes. "Lipid composition and lipases of Angiostrongylus cantonensis (nematoda: metastrongyloidea) /." [Hong Kong : University of Hong Kong], 1989. http://sunzi.lib.hku.hk/hkuto/record.jsp?B12583273.
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Hitchcock, C. A. "Antifungal agents and membrane lipids of Candida albicans." Thesis, Bucks New University, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.382567.
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Bolton-Smith, C. "The effect of dietary fats on membrane lipid composition and atherogenesis." Thesis, University of Southampton, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.254369.
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Charalambous, Kalypso Nicola. "The effect of lipid bilayer composition on small multidrug resistance transporters." Thesis, University of Bristol, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.432740.
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Jamieson, Elizabeth Cherry. "Human brain lipid fatty acid composition in relation to infant diet." Thesis, Connect to e-thesis, 1998. http://theses.gla.ac.uk/981/.
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Thesis (Ph.D.) - University of Glasgow, 1998.Ph.D. thesis submitted to the Faculty of Medicine, University of Glasgow, 1998. Research carried out in the Departments of Pathological Biochemistry and Child Health, Royal Hospital for Sick Children, Yorkhill NHS Trust. Includes bibliographical references. Print version also available.
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Nada, Filipović. "Uticaj sastava i uloge lipida brašna u procesu izrade hleba." Phd thesis, Univerzitet u Novom Sadu, Tehnološki fakultet Novi Sad, 1998. https://www.cris.uns.ac.rs/record.jsf?recordId=71440&source=NDLTD&language=en.
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Apstrakt je obrađen tehnologijama za optičko prepoznavanje teksta (OCR)Utvrdeni su sastav i količine nepolarnih i polarnih lipida kao i lipida iz skroba u pojedinim fazama izrade hleba na dva uzorka brašna od kvalitetne pšenice. Takode su odredene promene i prelazi lipidnih sastojaka pod uticajem fizičkih, mehaničkih i toplotnih delovanja tokom tehnološkog postupka.Na osnovu sastava masnih kiselina u lipidnim jedinjenjima razdvojenim tankoslojnom hromatografijom i računa verovatnoće utvrđen je njihov najverovatniji sastav.Iz ekstrakta nepolarnih lipida brašna kvantitativno je identifikovano preko 60 %, a iz hleba preko 40 % lipidnih jedinjenja (ASG, MG i TG).U ekstraktima polarnih lipida identifikovano je preko 60 % jedinjenja (DGMG, DGDG, MGMG i MGDG) a u lipidima unutar skroba zastupljeni su samo LPI i NAPE.U ekstraktima lipida i u lipidnim jedinjenjima identifikovano je oko 98 % masnih kiselina a najveći udeo je lilinolne kiseline.Takođe je ispitan uticaj načina dodavanja tri vrste komercijalnih emulgatora u pojedinim fazama izrade testa na kvalitet hleba.Delovanje komercijalnih emulgatora u testu i hlebu zavisi od vrste, sastava i i količine emulgatora kao i od kvaliteta brašna kome se dodaje. Poboljšavajući efekti se mogu postići samo ako se emulgator dozira na početku zamesa ili tokom razvoja testa.Rezultati ovog rada su pomogli da se bliže odredi mesto i uloga lipidnih materija brašna u procesu izrade hleba kao i interakcija lipida brašna sa komercijalnim emulgatorima.Abstract was processed by technology for Optical character recognition (OCR).Composition and quantities of nonpolar, polar and starch lipids were identified in different stages of bread making process. Changes and translocations of lipid compounds influenced by physical, mechanical and heat treatment during the technological process were determined, too.Based on fatty acid composition in different lipid compounds separated by TLC and on probability calculation, the most probable composition of them was est imated.In nonpolar lipid extracts of flour, over 60 % and in bread over 40 % of lipid compounds were identified (ASG, MG and TG).In polar lipid extracts over 60 % of lipid compounds were identified (DGMG,DGDG, MGMG and MGDG) but in starch lipids only LPI and NAPE were present.In lipid extract and lipid compounds about 98 % of fatty acids were identi- fied with the greatest shane of linoleic acid.The influence of adding three commercial emulsifiers in different stages of dough making on bread quality was also invest igated.Acting of commercial emulsifiers in dough and bread depends on their type, composition and quantity, as well as, on flour quality. Improving effects can be achieved only if emulsifiers ane added at the beginning of mixing stage or during dough development.These results comprise to better understanding of the lipid compounds role, the place of their acting in breadmaking process as well as their interaction with commercial emulsifiers.
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Chang, Huey-Huey 1962. "Dietary fat effects on egg yolk lipid composition and hepatic lipogenic enzymes." Thesis, The University of Arizona, 1990. http://hdl.handle.net/10150/277290.
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Menhaden oil, corn oil, olive oil or animal fat (1, 3, 5 or 8% of diet) effects on egg yolk fatty acids and hepatic lipogenic enzymes were studied in 35 week-old laying hens. Except for significantly lowered egg weights by menhaden oil, performance was unaffected. Yolk saturated fat remained constant (33-38% of yolk fat) regardless of fat source. Maximum o-3 fatty acid incorporation (.31 g/yolk) was reached with a deposition efficiency of 36.3% by feeding 5% menhaden oil. Yolk lipid contained.3% linolenic (C18:3o3), 1.0% eicosapentaenoic (C20:5o3), and 3.8% docosapentaenoic (C22: 5o3) acids. Maximum o-6 fatty acid incorporation (1.65 g/yolk) occurred with 17% efficiency when 8% corn oil was fed, primarily by increasing linoleic acid to 25.5%. Yolk oleate was inversely related to dietary linoleate. Only the highest menhaden oil levels significantly affected lipogenic enzymes: fatty acid synthetase and ATP citrate lyase (EC 4.1.3.8) activities were inhibited, while glucose-6-phosphate dehydrogenase (EC 1.1.1.49) activity was 2-3 times that of hens fed the basal diet. Malic enzyme (EC 1.1.1.40) activity was not significantly influence by dietary fat.
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Bennoson, Janet. "The effect of manipulating the macronutrient composition of meals postprandial lipid metabolism." Thesis, University of Southampton, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.310698.
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Dyda, Rachael Y. "Linking phylogeny and lipid composition of natural bacterial communities in arctic waters." College Park, Md. : University of Maryland, 2005. http://hdl.handle.net/1903/3252.
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Thesis (M.S.) -- University of Maryland, College Park, 2005.Thesis research directed by: Marine, Estuarine, Environmental Sciences Graduate Program. Title from t.p. of PDF. Includes bibliographical references. Published by UMI Dissertation Services, Ann Arbor, Mich. Also available in paper.
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Li, Tong. "Lipid Class Composition of Oysters, Crassostrea virginica, Exposed to Sediment-Associated PAHs." W&M ScholarWorks, 1996. https://scholarworks.wm.edu/etd/1539617705.
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Monteiro, Regina Teresa Rosim. "Lipid production and composition in haploid and diploid strains of Aspergillus nidulans." Thesis, University of St Andrews, 1985. http://hdl.handle.net/10023/14174.
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Six auxotrophic mutants of A. nidulans were crossed in a dialell cross system to obtain heterokaryous and heterozygous diploids. In order to ascertain their lipid accumulation ability, some of these mutants and diploids were tested in a minimal medium (with 3% glucose + 0.6% NaNO3), either in a shaker or in an incubator without agitation. Both, the mutants and diploids, exhibited only 4.6% lipid, on a dry weight basis. With the aim of optimising culture conditions for lipid accumulation, a wild type was cultivated in a range of different media and cultural conditions. The best yield (about 24%), was achieved in a modified minimal medium (MM + 12% glucose + 0.1% NaNO3), with a vortex stirrer device. The lipid composition of wild type 16 grown in a fermenter was determined. The results obtained from cells grown in two different media and using two extraction methods were compared. Fractionation of the total lipid on a Florisil column showed that this strain is composed of 86% neutral lipid, 7% glycolipid and 7% phospholipid, after isopropanol (IP) extraction, whilst chloroform-methanol (CM) extraction gave 75% neutral lipid, 8% glycolipid and 17% phospholipid. A further fractionation on hydrated Florisil showed that CM extracted sterols (both free and esterified) more efficiently than IP. Therefore, CM was considered a better extraction method, particularly for protein-bound lipids. The separation of the neutral lipid fraction into sub-classes also showed that the enhanced lipid content achieved in modified minimal medium, compared with a previously reported medium, was accounted for mainly by an increase, not in the triglycerides as was expected, but in the amount of sterols. TLC analysis of glycolipid and phospholipid from IP and CM extraction demonstrated two major glycolipid components (monoglycosyl and diglycosyl diglycerides) and that phosphatidylcholine (PC) and phosphatidylethanolamine (PE) were the principal phospholipids with lesser amounts of phosphatidylinositol, phosphatidylserine, phosphatidylglycerol, cardiolipin and phospbatidic acid (PA) after CM extraction, whilst after IP extraction only PC, PE and PA were found. Another significant difference between the two extraction methods is the large amount of PA found after CM extraction, but not after IP, showing that, almost certainly, phospholipase D activity had occurred during the process of extraction and/or storage of the lipid. It was also found that the principal phospholipid attacked by the enzyme was PC. The fatty acid composition was determined by GLC. The major fatty acids found in the total lipid were: 16:0 =21%; 17:0 =5%; 18:0 =18%; 18:1 = 20%; 18:2 = 35%. Each lipid class showed a different and distinctive fatty acid composition, exhibiting variation with the growth medium and extraction method used. Of particular interest was the sterol ester fraction which contained margarinic acid (17:0) as its only fatty acid.
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Kurt, Esra. "Associations between lipid composition, shelf life and sensory quality in ruminant meats." Thesis, University of Bristol, 1999. http://hdl.handle.net/1983/a77d9a0c-f888-4650-b6b8-7c1b8f5cee45.
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Alomaim, Haya. "Effects of Dietary Calcium on Body Composition and Lipid Metabolism in Rats." Thesis, Université d'Ottawa / University of Ottawa, 2018. http://hdl.handle.net/10393/37602.
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Calcium (Ca) intakes may affect cardiovascular disease risk by altering body weight/fat and serum lipid profile, but results have been inconsistent and the underlying mechanisms are not well understood. Thus, the effects of dietary Ca on body composition and lipid metabolism were examined in male Sprague-Dawley rats. Rats were fed high-fat, high-energy diets containing (g/kg) low (0.75Ca, 0.86 ± 0.05; 2Ca, 2.26 ± 0.02), normal (5Ca, 5.55 ± 0.08) or high (10Ca,11.03 ± 0.17; 20Ca, 21.79 ± 0.15) Ca for 10 weeks. At the end of the study the 0.75Ca group had lower (p < 0.05) body weight and fat mass compared to other groups. Rats fed the high Ca diets had lower serum total and LDL cholesterol compared to rats fed normal or low Ca. Liver total
cholesterol was lower in rats fed high compared to low Ca. In general, liver mRNA expression of the LDLR and genes involved in cholesterol synthesis (HMGCR and HMGCS1), fatty acid oxidation (CPT2) and cholesterol esterification (ACAT2) were higher in rats fed higher Ca.
Apparent digestibility of total trans, saturated, monounsaturated and polyunsaturated fatty acids was lower in rats fed the high compared to the low Ca diets, but the differences were greatest for trans and saturated fatty acids. Fecal excretion of cholesterol and total bile acids was highest in rats fed the 20Ca diet. The results suggest little effect of dietary Ca on body composition unless Ca intakes are very low. Decreased bile acid reabsorption and reduced absorption of neutral
sterols and trans and saturated fatty acids may contribute to the improved serum lipid profile in rats fed higher Ca.
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Zampelas, Antonios. "Effect of dietary fatty acid structure and composition on postprandial lipid metabolism." Thesis, University of Surrey, 1993. http://epubs.surrey.ac.uk/770401/.
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In this thesis effects of dietary fatty acid composition and of positional distribution of fatty acids in dietary TAG, on postprandial lipid and hormone responses, were investigated. A6 week fish oil supplementation period (2.7 g n-3 fatty acids per day) decreased fasting TAG and increased TC (p<0.05) and LDL-C (p<0.05) levels in normal subjects. Postprandial plasma TAG responses to a test meal were also significantly reduced following the fish oil supplementation period (area under the response curves, p<0.001). Apolipoproteins A-I and B responses did not alter in response to chronic fish oil supplementation. Type II diabetics responded differently to normal subjects to fish oil supplementation. Fasting lipid and apolipoprotein levels were not significantly altered, and the postprandial TAG response to a test meal showed a trend towards higher values following the fish oil supplementation period. In the study of effects of dietary TAG structure on postprandial lipid apolipoprotein (A-I, B), hormone (insulin, GIP) and glucose responses, no effect of test meals differing in the positional distribution of palmitic acid at the sn-2 or the sn-3 positions of the TAG molecule were seen. In a study of acute effects of dietary fatty acid composition in healthy male subjects, a fish oil test meal (40 g fish oil concentrate), significantly reduced plasma TAG postprandial responses compared with a mixed oil meal (containing 40 g of a mixture of oils high in SFA and mimicking the current U. K. dietary fat intake), p<0.05. Post-heparin LPL activity was also significantly increased 12 hours following the fish oil test meal (p<0.01). A 40 g corn oil test meal did not have any significant effect on postprandial lipid, hormone (insulin and GIP), and retinyl palmitate levels (the latter was administered with each test meal-700 I. U. /kg of body weight) compared with the other two test meals. A feeding study, using a rat model, showed that following two weeks of a fish oil diet (5%, w/w) the postprandial incorporation of [U-t4C]glucose into hepatic total lipids and TAG measured in vitro, was significantly reduced compared with rates measured in animals on a mixed oil diet (p<0.05). In the presence of the two anabolic hormones, insulin and GIP, in vitro rates of hepatic cholesterogenesis increased (p<0.05), and these effects of hormones were independent of the type of the diet fed. In addition, plasma TAG levels were significantly lower in the fish oil group compared with levels in the mixed oil and corn oil dietary groups (p<0.05), and plasma insulin levels were significantly higher in the mixed oil dietary group than in the other two groups (p<0.001).
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Azevedo, Vítor Manuel Madureira. "Lipidomic study of the red marine macroalgae as source of bioactive compounds." Master's thesis, Universidade de Aveiro, 2016. http://hdl.handle.net/10773/17513.
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Mestrado em Mestre em Bioquímica, ramo da Bioquímica ClínicaMarine macroalgae, or seaweeds, have gained an increased interest in recent times for the use in various biotechnological applications, due to the added-value of their chemical constituents. Among them, glycolipids and phospholipids display several commercial applications in a wide spectrum of industries, such as food, pharmaceutical and cosmetic. In an effort to further understand the lipid composition of macroalgae, the present work reports, for the first time, the isolation and characterization of the polar lipid profile of the red macroalgae Porphyra dioica cultivated on a land-based integrated multi-trophic aquaculture (IMTA) system, using a lipidomic-based approach employing hydrophilic interaction liquid chromatography-eletrospray ionization mass spectrometry (HILIC-ESI-MS). The fatty acid profile of this species of seaweed was also determined, accounting for season variability and its life cycle. The polar lipid profile of P. dioica revealed the presence of over 69 molecular species, corresponding to glycolipids (sulfoquinovolsyldiacylglycerols, sulfoquinovosylmonoacylglycerols, digalactosyldiacylglycerols) and glycerophospholipids (lyso- and phosphatidylglycerols), lyso- and phosphatidylcholines), as well as phytyl derivatives. Some of these polar lipids contain polyunsaturated fatty acids (PUFAs), namely arachidonic acid (C20:4) and eicosapentaenoic acid (C20:5), thus revealing the ability of P. dioica to biosynthesize this long chain PUFAs. P.dioica from the winter season revealed to be richer in PUFA content, accounting for 37.0% of total fatty acid (TFA) content, as opposed to P. dioica from the summer season (25.0% of TFA content). Eicosapentaenoic acid (EPA) content was revealed to be being significantly higher in the winter season (25.2% of TFA content). The diploid sporophyte conchocelis phase of P. dioica showed to possess the highest amount of PUFAs (47.0% of TFA content), with arachidonic acid being the most abundant fatty acid (21.2% of TFA content). Several of the lipids identified have been reported to possess nutritional and health benefits, thus allowing the valorisation of P. dioica from IMTA as a source of bioactive compounds, adequate for the use in a wide range of different applications and as a functional food, rich in omega-3 fatty acids.
As macroalgas têm vindo a ganhar um interesse cada vez maior para o uso em diversas aplicações biotecnológicas, devido ao valor acrescentado dos seus diferentes constituintes. Entre estes, os glicolípidos e os fosfolípidos podem ser usados comercialmente em diferentes indústrias, tais como as indústrias alimentar, farmacêutica e cosmética. Com o objetivo de compreender melhor a composição lipídica das macroalgas, o presente trabalho relata, pela primeira vez, a caracterização do perfil de lípidos polares da macroalga vermelha Porphyra dioica, cultivada num sistema de aquacultura multi-trófica integrada (IMTA), utilizando para esse fim uma abordagem lipidómica baseada na espectrometria de massa (HILIC-ESI-MS). Foi também determinado o perfil de ácidos gordos da referida espécie de alga, tendo em consideração a variabilidade sazonal e o seu ciclo de vida. O perfil de lípidos polares da alga P. dioica revelou a presença de mais de 69 espécies moleculares diferentes, correspondendo a classes de glicolípidos (sulfoquinovosildiacilgliceróis, sulfoquinovosilmonoacilgliceróis e digalactosildiacilgliceróis), fosfolípidos (liso- e fosfatidilglicerol, liso- e fosfatidilcolinas) e derivados fitil. Alguns destes lípidos polares contêm ácidos gordos polinsaturados (PUFAs) na sua composição, nomeadamente o ácido araquidónico (C20:4) e ácido eicosapentaenóico (C20:5), revelando, assim, a capacidade da alga P. dioica em biossintetizar este tipo de ácidos gordos polinsaturados de cadeia longa. Considerando a variação sazonal do conteúdo em ácidos gordos, a P. dioica cultivada no inverno revelou ser mais rica em PUFAs, correspondendo a 37.0% do conteúdo total de ácidos gordos, contrariamente à P. dioica cultivada no verão (25.0%). O conteúdo em ácido eicosapentaenóico (EPA) é significativamente maior na estação de inverno (25.2%). O perfil em ácidos gordos também variou com o ciclo de vida P. dioica, sendo que na fase de conchocelis a quantidade de PUFA é significativamente mais elevada (47.0% de conteúdo de ácidos gordos), sendo o ácido araquidónico o ácido gordo mais abundante (21.2% de conteúdo de ácidos gordos).Várias classes de lípidos polares foram identificados como possuindo benefícios nutricionais e para a saúde, permitindo assim a valorização da alga vermelha P. dioica produzida em IMTA como uma fonte de compostos bioativos, adequados para o uso numa grande variedade de aplicações como um alimento funcional, rica em ácidos gordos polinsaturados ómega-3.
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White, Philip Lewis. "The effects of environmental warming on Antarctic soil microbial communities." Thesis, University of London, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.340641.
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Hughes, David Aled. "Regulation of lymphocyte stimulation by lipid components of lung lining fluid and changes in lipid composition in chronic inflammatory lung diseases." Thesis, Imperial College London, 1991. http://hdl.handle.net/10044/1/46831.
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Durnford, Edward A. D. "Lipid composition of selected tissues and milk of phocid seals of eastern Canada." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape10/PQDD_0018/MQ54891.pdf.
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Li, Ling. "The analysis of global gene expression related to starch, lipid and protein composition." [Ames, Iowa : Iowa State University], 2006.
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Brown, Angela Carin Wrenn Steven Parker. "The effect of lipid composition on cholesterol-rich domain size in model membranes /." Philadelphia, Pa. : Drexel University, 2008. http://hdl.handle.net/1860/2809.
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Joseph, Shama Vasanthi. "Effect of different conjugated linoleic acid isomers on lipid metabolism and body composition." Thesis, Université Laval, 2010. http://www.theses.ulaval.ca/2010/27641/27641.pdf.
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Rasheed, Nabeela. "The effects of sterol biosynthesis inhibitors on the lipid composition of Apium graveolens." Thesis, University of Liverpool, 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.385160.
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James, Alexander David. "Membrane lipid composition response to growth conditions in prokaryotic extremophiles and non-extremophiles." Thesis, University of Bristol, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.368216.
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Du, Plessis Michelle. "The role of carnitine in eukaryotic cells : Using yeast as a model." Thesis, Stellenbosch : Stellenbosch University, 2015. http://hdl.handle.net/10019.1/97946.
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Thesis (MSc)--Stellenbosch University, 2015.ENGLISH ABSTRACT: Previous studies in yeast in this laboratory have found carnitine to be both protective against oxidative stress induced by hydrogen peroxide and to increase the detrimental effect of dithiothreitol. These phenotypes were found to be independent of the role of carnitine within the carnitine shuttle. A screen for suppressor mutations for these carnitine-dependent phenotypes identified, among others, Δcho2 and Δopi3. Cho2p and Opi3p catalyse the sequential methylation reactions in the formation of phosphatidylcholine from phosphatidylethanolamine. Therefore, this study aimed to investigate the relationship between choline, phosphatidylcholine and the carnitine phenotypes. Liquid growth assays of Δcho2 and Δopi3 cultures revealed that addition of choline can restore the protective effects of carnitine against hydrogen peroxide. The connection between the cellular phospholipid composition and the carnitine-dependent shuttleindependent phenotypes was also investigated. Analysis of the lipid composition of cells by LCMS showed that Δcho2 and Δopi3 had a largely different lipid composition compared with the wild type, most notably, a reduction in phosphatidylcholine and an increase in triacylglycerol content were observed for both mutants. These changes were reversed by supplementation with choline. However, no effects on the lipid composition of cells in response to carnitine treatment were observed, either when supplemented alone or in combination with DTT and hydrogen peroxide. Carnitine has also been investigated in mammalian systems for its potential to protect cells from oxidative stress, an effect which would be of benefit in various neurodegenerative disorders. Several studies have documented the positive effects of carnitine against oxidative stress in mammalian cells however the mechanism behind this action remains unknown. It is therefore thought that, provided similar effects for carnitine can be shown in mammalian cells as was observed in yeast, it would be beneficial to use yeast as a model system for the study of the molecular changes induced by carnitine. In view of this, the effects of carnitine on toxicity induced by oxidative stress in mammalian neural cells were compared to that which has been observed in yeast. For this purpose the 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyl tetrazolium bromide (MTT) assay, a measure of reductive capacity of cells, was used. However, no effects for carnitine were observed in the MTT assay in combination with either dithiothreitol or paraquat.
AFRIKAANSE OPSOMMING: Vorige studies op gis in hierdie laboratorium het bevind dat karnitien beskermend is teenoor oksidatiewe stres wat deur waterstofperoksied geïnduseer word en ook die nadelige effek van ditiotreitol verhoog. Hierdie fenotipes is gevind om onafhanklik te wees van die rol van karnitien binne die karnitien-pendel. Die sifting vir onderdrukker-mutasies van hierdie karnitienafhanklike fenotipes het onder andere Δcho2 en Δopi3 geïdentifiseer. Cho2p en Opi3p kataliseer die opvolgende metileringsreaksies tydens die vorming van fosfatidielcholien vanaf fosfatidieletanolamien. Hierdie studie het dus gepoog om die verhouding tussen cholien, fosfatidielcholien en die karnitienfenotipes te ondersoek. Vloeistofanalises van Δcho2- en Δopi3-kulture het aangedui dat die byvoeging van cholien die beskermende effekte van karnitien teenoor waterstofperoksied kan herstel. Die verband tussen die sellulêre fosfolipiedsamestelling en die karnitienafhanklike pendel-onafhanklike fenotipes is ook ondersoek. Die analise van die lipiedsamestelling van selle deur middel van LCMS het getoon dat Δcho2 en Δopi3 ‘n grootliks verskillende samestelling het in vergelyking met die wilde tipe, en daar is veral ‘n afname in fosfatidielcholien en ‘n verhoging in triasielgliserol-inhoud vir beide mutante waargeneem. Hierdie veranderinge is omgekeer deur aanvulling met cholien. Geen effekte op die lipiedsamestelling van die selle is egter in reaksie op die karnitienbehandelings waargeneem nie, hetsy toe dit alleen aangevul is of in kombinasie met ditiotreitol en waterstofperoksied. Karnitien is ook in soogdierstelsels ondersoek vir sy potensiaal om selle teen oksidatiewe stres te beskerm, ‘n effek wat groot voordeel sal inhou vir verskeie neurodegeneratiewe steurings. Verskeie studies het reeds die positiewe effekte van karnitien teen oksidatiewe stres in soogdierselle opgeteken, hoewel die meganisme agter hierdie werking nog onbekend is. Daar word dus vermoed dat, gegewe dat soortgelyke effekte vir karnitien in soogdierselle getoon kan word as wat in gis waargeneem is, dit voordelig sou wees om gis as ‘n modelsisteem vir die studie van die molekulêre veranderinge wat deur karnitien geïnduseer word, te gebruik. In die lig hiervan is die effekte van karnitien op giftigheid wat deur oksidatiewe stres in soogdiersenuselle geïnduseer is, vergelyk met dít wat in gis waargeneem is. Om hierdie rede is die 3-[4,5-dimetieltiasool-2-iel]-2,5-difeniel tetrasoliumbromied (MTT) essaiëring, ‘n meting van die verminderende kapasiteit van selle, gebruik. Geen effekte vir karnitien is egter met die MTT essaiëring in kombinasie met óf ditiotreitol óf parakwat waargeneem nie.
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Chae, Sung Hee. "Conjugated linoleic acid reduces lipid oxidation in irradiated, cooked ground beef patties." Diss., Texas A&M University, 2005. http://hdl.handle.net/1969.1/5983.
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This study was conducted to examine the antioxidative effect of conjugated linoleic acid (CLA) in irradiated, cooked ground beef patties. The hypothesis was that CLA would be retained during irradiation and would reduce lipid oxidation that is caused by irradiation. The objective was to evaluate the effects of CLA alone and in combination with irradiation on lipid oxidation, fatty acid composition, cooking loss, moisture and fat content, and trained panel sensory evaluations of beef patties. CLA was added at 0, 1, 2, or 4% level during the grinding process. Addition of CLA during the grinding process increased CLA cis-9,trans-11 and CLA trans-10,cis-12 isomers in both irradiated and non-irradiated cooked ground beef patties (irradiated at 1.6 kGy) (P = 0.0001). Weight loss during cooking was greater in irradiated beef patties than in non-irradiated patties (P = 0.004). Irradiation reduced the serumy/bloody aromatic attribute and increased browned aromatic attribute, browned aftertaste, and wet dog/hairy aromatic attribute (P < 0.05). There was no significant main effect of irradiation on the basic tastes. The linoleic acid, CLA cis-9,trans-11, and CLA trans-10,cis-12 were decreased by irradiation (P < 0.05). Although irradiation decreased the CLA isomers, higher percentages of CLA isomers were retained in irradiated patties containing a 4% free fatty acid preparation of CLA (FFA-CLA), reflecting the ability of the FFA preparation to reduce lipid oxidation that is caused by irradiation. The thiobarbituric acid reactive substances (TBARS) values were significantly higher in irradiated, cooked ground beef patties than in non-irradiated ground beef patties (P = 0.004). Although the FFA-CLA was effective in reducing lipid oxidation that is caused by irradiation, it increased painty aromatic attribute, bitter taste, and astringent aftertaste due to the soapy flavor of the free fatty acid (all P < 0.05). The FFA-CLA decreased cooked beef/brothy and serumy/bloody aromatic attribute and browned aftertaste (all P < 0.05). The 1% triacylglycerol (TAG) preparation of CLA reduced TBARS in irradiated, cooked patties to levels seen in control, non-irradiated patties. The 1% TAG concentration also provided good retention of CLA in the cooked ground beef.
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Turner, Nigel. "Membrane lipid composition and its effect on sodium pump molecular activity a comparative study /." Access electronically, 2003. http://www.library.uow.edu.au/adt-NWU/public/adt-NWU20041025.154427.
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Dorrance, Anne McLaren. "Cell membrane lipid composition in relation to physical properties and function : a methodological study." Thesis, University of Glasgow, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.360931.
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Espiritu, Wilma. "The Influence of Lipid Composition on the Binding of LDL to Chondroitin 6-Sulphate." VCU Scholars Compass, 2005. http://scholarscompass.vcu.edu/etd/943.
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The interaction between low-density lipoprotein (LDL) and glycosaminoglycans is a key factor in atherosclerosis. The present study examines the characteristics of LDL and its binding properties with the main glycosaminoglycan of the vascular wall, chondroitin 6- sulphate (C6S). The compositional characteristics that were studied for each LDL sample were phase transition temperature, phospholipid content, free cholesterol content, cholesteryl ester content, triglyceride content, and size. Correlations of these characteristics with LDL-C6S binding were analyzed using a turbidity assay. Our results showed that there is no correlation between LDL-C6S binding and phase transition temperature, triglyceride content, or size. Strong correlations were present for LDL-C6S binding and phospholipid content (P < 0.0001, r2 = 0.4591), free cholesterol content (P < 0.01, r2 = 0.2495), and cholesteryl ester content (P < 0.005, r2 = 0.2952). When values for surface (phospholipids and free cholesterol) and core (cholesteryl esters and triglycerides) lipids were determined a positive correlation was also present with LDL-C6S binding (P < 0.0005, r2 = 0.4172; P < 0.0005, r2 = 0.4282; respectively). These results indicate that large, lipid-rich LDL particles have a higher capacity to bind C6S than smaller, lipid poor LDL. Possible implications for the atherogenicity of LDL are discussed.
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Furimsky, Anna M. "Characterization of the lipid composition of washed and percoll gradient centrifuged epididymal mouse sperm." Thesis, University of Ottawa (Canada), 2001. http://hdl.handle.net/10393/9396.
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Capacitation is an important yet poorly understood process during which the fluidity of the sperm membrane increases to prepare sperm for the acrosome reaction (AR) and subsequent sperm-egg binding. While cholesterol efflux may be partially responsible for this increase, modification of lipid components, such as remodeling of specific phospholipid (PL) bound unsaturated fatty acyl chains, may also be involved, since no change in the cholesterol:PL molar ratio following capacitation in mouse has been previously described. In this study, lipid classes (cholesterol, PL, sulfogalactosylglycerolipid (SGG), diacylglycerol and triacylglycerol) were quantified and the fatty acyl chain compositions of phosphatidylcholine (PC) and phosphatidylethanolamine (PE) were characterized in washed non-capacitated (WS), washed capacitated (WCS), and Percoll gradient centrifuged (PGC) capacitated (PGCS) epididymal mouse sperm. Fatty acid methyl esters were generated from PC and PE by acid methanolysis and their identity was analyzed by gas chromatography. (Abstract shortened by UMI.)
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Howard, Brandon Daniel. "Shear and Composition Effects on Porous Network Properties and the Permeability of Lipid Films." The Ohio State University, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=osu1593680466745792.
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Xu, Yuanda. "Thermodynamic and Hydrodynamic Coupling Effects on Compositional Lipid Domains in Membrane Stack Systems." Thesis, Princeton University, 2018. http://pqdtopen.proquest.com/#viewpdf?dispub=10642189.
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This dissertation will focus on my work in biophysics, and my work in mean field games and glucose predictive analysis will not be presented. Several problems relating to the effects of thermodynamic coupling and hydrodynamic coupling within the membrane stack system are discussed. Three theoretical approaches are employed and proposed to study the membrane stack system: a diffuse-interface approach is utilized for numerical simulations; a coarse-grained sharp-interface approach is utilized to provide physical understanding of various kinetics; a hybrid intermediate sharp-interface approach is adopted to study the domain coalescence in the absence of diffusion.
In the first part of the thesis, we discuss the thermodynamic coupling in membrane stack systems. Comprehensive analyses are presented to understand the accelerated coarsening kinetics with respect to single layer and long-range alignment. Numerical simulations are conducted for three systems, namely a diffusion dominated system, an advective interlayer friction dominated system, and an advective membrane viscosity dominated system. Experimental results regarding the advective interlayer friction dominated system are supported by simulations. We investigate the mechanism of the enhanced coarsening kinetics in membrane stack systems and the relationship between the coarsening process and vertical alignment. An intuitive understanding along with analytical explanations are further presented. Moreover, numerical results regarding the critical mixture are also discussed.
We then investigate the interfacial fluctuation behavior within membrane stack systems. The hydrodynamic coupling is found to play a significant role and several physical length scales are found to be crucial. Both a sharp-interface approach and a diffuse-interface approach are employed to numerically simulate decay of interface fluctuations in representative two-membrane systems.
To measure the thermodynamic coupling in experiments, the hydrodynamic force needs to be quantified, especially for the non-circular domains. In the last part of this thesis, the drag coefficient relating domain velocity and force acting on the domain is calculated using perturbation theory within two limits: the first limit refers to a domain much larger than the hydrodynamic screening length; the second limit refers to a domain that is much smaller than the hydrodynamic screening length.
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Ariöz, Candan. "Exploring the Interplay of Lipids and Membrane Proteins." Doctoral thesis, Stockholms universitet, Institutionen för biokemi och biofysik, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-102675.
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The interplay between lipids and membrane proteins is known to affect membrane protein topology and thus have significant effect (control) on their functions. In this PhD thesis, the influence of lipids on the membrane protein function was studied using three different membrane protein models. A monotopic membrane protein, monoglucosyldiacylglyecerol synthase (MGS) from Acholeplasma laidlawii is known to induce intracellular vesicles when expressed in Escherichia coli. The mechanism leading to this unusual phenomenon was investigated by various biochemical and biophysical techniques. The results indicated a doubling of lipid synthesis in the cell, which was triggered by the selective binding of MGS to anionic lipids. Multivariate data analysis revealed a good correlation with MGS production. Furthermore, preferential anionic lipid sequestering by MGS was shown to induce a different fatty acid modeling of E. coli membranes. The roles of specific lipid binding and the probable mechanism leading to intracellular vesicle formation were also investigated. As a second model, a MGS homolog from Synechocystis sp. PCC6803 was selected. MgdA is an integral membrane protein with multiple transmembrane helices and a unique membrane topology. The influence of different type of lipids on MgdA activity was tested with different membrane fractions of Synechocystis. Results indicated a very distinct profile compared to Acholeplasma laidlawii MGS. SQDG, an anionic lipid was found to be the species of the membrane that increased the MgdA activity 7-fold whereas two other lipids (PG and PE) had only minor effects on MgdA. Additionally, a working model of MgdA for the biosynthesis and flow of sugar lipids between Synechocystis membranes was proposed. The last model system was another integral membrane protein with a distinct structure but also a different function. The envelope stress sensor, CpxA and its interaction with E. coli membranes were studied. CpxA autophosphorylation activity was found to be positively regulated by phosphatidylethanolamine and negatively by anionic lipids. In contrast, phosphorylation of CpxR by CpxA revealed to be increased with PG but inhibited by CL. Non-bilayer lipids had a negative impact on CpxA phosphotransfer activity. Taken together, these studies provide a better understanding of the significance of the interplay of lipids and model membrane proteins discussed here.
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Chen, Jia. "Effect of Nitrogen and Phosphorus Enrichment on Lipid and Fatty Acid Composition of Estuarine Microplankton." W&M ScholarWorks, 1989. https://scholarworks.wm.edu/etd/1539617601.
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Buckley, Melanie. "Studies on the effect of interleukin-33 on gene expression and lipid composition of macrophages." Thesis, Cardiff University, 2014. http://orca.cf.ac.uk/67679/.
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The atherosclerotic plaque is characterised by the presence of macrophage foam cells that arise from dysfunctional cholesterol metabolism and trafficking. Cytokines are highly expressed within the plaque and play a critical function in initiating and augmenting the disease state. Previous studies have shown that the novel cytokine, interleukin-33 (IL-33), exerts anti-atherogenic actions in animal and in vitro models of the disease. The effect of IL-33 on pro-atherosclerotic markers was assessed in human THP-1 and murine RAW264.7 macrophages and primary human monocyte-derived macrophages (HMDMs) by real time-quantitative polymerase chain reaction (RT-qPCR). The studies then focused on characterising the signalling pathways involved in the regulation of intercellular adhesion molecule-1 (ICAM-1) and monocyte chemotactic protein-1 (MCP-1) expression by IL-33. The expression of key signalling components implicated in atherosclerosis were knocked down by RNA interference (RNAi). These experiments demonstrated that the extracellular signal-regulated kinase (ERK)-1 and -2, p38α, c-Jun N-terminal kinase (JNK)-1 and -2, phosphoinositide-3-kinase (PI3K)-γ, p50 and p65 NF-κB were integral to the IL-33-mediated down-regulation of ICAM-1 and MCP-1 gene expression in THP-1 macrophages. Another key aim was to analyse the effects of IL-33 stimulation on the lipid profiles of macrophages. A combination of thin layer chromatography (TLC) and gas chromatography (GC) was used to assess the fatty acid composition of THP-1 and RAW264.7 macrophages following IL-33 treatment. The cytokine promoted the redistribution of fatty acids and caused a general increase in saturated fatty acids (SFAs), accompanied with a reduction in monounsaturated fatty acids (MUFAs). Additionally, IL-33 increased the content of n-3 polyunsaturated fatty acids (PUFAs) whereas the impact on n-6 PUFAs was more specific to particular fatty acids and varied between the two species. Overall, the cytokine enhanced the levels of PUFAs involved in eicosanoid production. Also, IL-33 influenced the precursors and products of desaturases and appropriately increased the activities of Δ-5 and Δ-6 desaturases but reduced stearoyl-CoA desaturase activity (SCD). The decrease in SCD activity was accompanied by a reduction in the mRNA expression of SCD-1 in RAW264.7 macrophages. The studies presented within this thesis provide new insights into the signalling pathways underlying the IL-33-mediated inhibition of gene expression in macrophages. Additionally, these experiments describe the novel effects of IL-33 stimulation on the lipid profile of macrophages.
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Shinde, Suhas, Shivakumar Devaiah, and Aruna Kilaru. "Profiling Abscisic Acid-Induced Changes in Fatty Acid Composition in Mosses." Digital Commons @ East Tennessee State University, 2017. https://dc.etsu.edu/etsu-works/4745.
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In plants, change in lipid composition is a common response to various abiotic stresses. Lipid constituents of bryophytes are of particular interest as they differ from that of flowering plants. Unlike higher plants, mosses have high content of very long-chain polyunsaturated fatty acids. Such lipids are considered to be important for survival of nonvascular plants. Here, using abscisic acid (ABA )-induced changes in lipid composition in Physcomitrella patens as an example, a protocol for total lipid extraction and quantification by gas chromatography (GC) coupled with flame ionization detector (FID) is described.
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Hunter, David Gregory. "The effects of lipid composition and extrusion pressure and temperature on the properties of phospholipid vesicles." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp04/mq24162.pdf.
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Berman, Michelle Lea. "Effects of Food Deprivation on Blood Lipid Concentration and Composition in Steller Sea Lions (Eumetopias Jubatus)." Master's thesis, University of Central Florida, 2005. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/2958.
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Steller sea lions, the largest Otariid, fast during their breeding season; during this time they refrain from ingesting food for a period of 12-43 days. Fasting, while undertaking an extremely energetically demanding activity (breeding and pupping), requires specific physiological adaptations. This study examined the physiological response to fasting of two age classes, juveniles and sub-adults, during the breeding and non-breeding seasons to determine how these animals utilize lipids and the pattern of fatty acid mobilization from lipid stores during fasting. Four juveniles and 5 sub-adults were fasted for one and two weeks, respectively, and blood samples were collected approximately every 3 days for lipid analysis. The concentrations of plasma non-esterified fatty acids (NEFA) were analyzed spectrophotometrically. Serum fatty acid composition was analyzed using gas chromatography (GC) and their individual weight percent (wt %) were correlated with their peak retention time and calculated using the area under each peak. Sixty-nine fatty acids were quantified from each sample. However, only those with concentrations above 0.2 wt. % were included in the analysis. Sub-adult samples were grouped on a percent mass loss basis (0%, 7-8% and 15% mass loss) to facilitate comparison with the juveniles. These data represent the total lipid fatty acid composition of each blood sample. Relative lipid concentration was calculated by multiplying the total lipid fatty acid compositional analysis (wt %) by the NEFA concentrations measured in that respective blood sample. Plasma NEFA concentrations in juvenile Steller sea lions ranged from 1.2 [plus or minus] 0.51 mM to 3.7 [plus or minus] 0.69 during fasting and was within the range of fasting phocids. Concentrations of NEFAs in the sub-adult Steller sea lions ranged from 1.00 mM up to 9.70 mM and were generally higher than fasting phocids. The wt % of only one fatty acid (20:0) was significantly different between the breeding and non-breeding season in fasting juveniles. However, the wt % of seven fatty acids changed significantly during fasting in the juveniles and five of these were most significant in separating the beginning and end of the fasts using principal components analysis. In contrast, the wt % of 10 fatty acids were significantly different during the breeding and non-breeding season fasts of the sub-adults. Additionally, the wt % of 10 fatty acids changed significantly during fasting in the sub-adults and four of these (16:1n-7, 18:2n-6, 20:0, and 20:1n-9) were most significant in separating the beginning and end of the fasts using principal components analysis. These trends reveal the physiological differences between the juvenile and sub-adult Steller sea lions and suggest that the sub-adults may be better physiologically and metabolically adapted to fast than the juveniles in this study.M.S.
Department of Biology
Arts and Sciences
Biology
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Kelso, Karen Anne. "The lipid and fatty acid composition of semen in relation to fertility in the male animal." Thesis, University of Glasgow, 1997. http://theses.gla.ac.uk/2145/.
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Spermatozoa are highly specialised cells which display a range of unique features associated with their crucial function of egg fertilisation. One of the most striking characteristics of spermatozoa, in biochemical terms, is the extremely high proportion of long chain highly polyunsaturated fatty acids present as components of the plasma membrane phospholipids. This high degree of unsaturation is almost unique amongst animal cells; the only other cell types which display similar levels of these polyunsaturates are the neurons of the brain and retina. The reason why spermatozoa exhibit such an unusual fatty acid composition is not clear but it is feasible that the highly unsaturated phospholipids may confer a high degree of flexibility on the sperm plasma membrane as well as provide a potential energy source in order to facilitate the characteristic flagellar motion of these cells. There is also evidence that spermatozoa lipids play a crucial role in the membrane fusion and signal transduction events associated with the acrosome reaction and fertilisation. Initial observations were made between the semen of domestic cockerel and bull with respect to animal ageing and semen quality. Within both species similar patterns were observed in that with age there was a loss of the long chain C20 and C22 polyunsaturated fatty acids accompanied by a loss of the major antioxidant enzyme systems. A decrease in phosphatidyl ethanolamine and an increase of phosphatidyl choline with age were also observed to be associated with a reduction in semen quality parameters and fertility in both species. In contrast cockerels displayed significant increases in spermatozoa and seminal plasma lipid levels where the bull exhibited losses, reflecting possible differences in spermatozoa metabolism and function.
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Kingston, Catharine Alison. "The effect of modulating membrane lipid composition on the thermal sensitivity of tumour cells in culture." Thesis, Durham University, 1989. http://etheses.dur.ac.uk/6533/.
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The plasma membrane, which separates intracellular contents from extra cellular milieu, consists of a lipid bilayer comprising mainly phospholipids and cholesterol together with various functional proteins, which control the interaction of the cell with its environment. Cells are killed at elevated temperatures and previous work suggests that the plasma membrane may be a primary target in this hyperthermic cell death. The present study set out to test this hypothesis using a rat liver tumour cell hue (Hepatoma Tissue Culture cells). Several different experimental approaches were adopted. Supplementation of these cells with linoleic acid (18 : 2) for a 36 hour period increased the thermal sensitivity of cells at 43 C, though increased sensitivity was not evident at other times. Plasma membrane-enriched fractions were obtained from control cells and from cells supplemented with linoleic acid for a 36 hour period, then lipids were extracted and characterised. Whilst there was little difference in the cholesterol : phospholipid ratio, the phospholipid fatty acid composition of membranes from supplemented cells showed elevated levels of 18 : 2 and decreased levels of oleic acid (18 : 1) relative to control cell membranes. DPH fluorescence polarisation studies indicated that plasma membranes from supplemented cells were less 'ordered' than control membranes. Alkaline phosphodiesterase I, a plasma membrane-bound enzyme, appeared to be more thermolabile in supplemented cells suggesting that plasma membrane 'fluidity' may be an important factor in determining the thermal sensitivity of this membrane-bound enzyme. Hyperthermic cell death was potentiated by the presence of local anaesthetics, two of which, dibucaine and tetracaine, also produced less 'ordered' membranes. Morphological studies conducted on cells in the presence and absence of local anaesthetic at elevated temperatures indicated changes in cellular surface morphology on heating which were accelerated in the presence of the anaesthetic. The intermediate filament network of these cells did not appear to be a primary target of hyperthermic treatment. These studies suggest that the lipid composition and physical state of the plasma membrane are critical features involved in the expression of cell death, possibly through a modulation of membrane protein thermal sensitivity.
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Garry, Jennifer Mary Christina. "The effect of dietary n-3 and n-6 PUFA intake on atheromatous plaque lipid composition." Thesis, University of Southampton, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.367970.
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Alfaia, Cristina Maria Riscado Pereira Mateus. "Contribution to the study of lipid composition and nutritional value of intramuscular fat in ruminant meats." Doctoral thesis, Universidade Técnica de Lisboa. Faculdade de Medicina Veterinária, 2009. http://hdl.handle.net/10400.5/1157.
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Tese de Doutoramento em Ciência e Tecnologia AnimalContribuição para o estudo da composição lipídica e do valor nutricional da gordura intramuscular na carne de ruminantes - A composição em ácidos gordos e o ácido linoleico conjugado (CLA) são temas actuais de grande interesse, com particular relevância para a qualidade da carne e saúde humana. As carnes de ruminantes têm sido consideradas alimentos pouco saudáveis, principalmente devido à sua fracção lipídica com elevada concentração em ácidos gordos saturados. Contudo, as gorduras edíveis dos ruminantes são a principal fonte natural de isómeros CLA, sendo os isómeros bioactivos (c9,t11 e t10,c12) associados a propriedades potencialmente benéficas para a saúde humana. Em Portugal, a informação científica disponível para apoiar a qualidade e a reputação da carne bovina de raças autóctones criadas segundo as especificações de Denominação de Origem Protegida (DOP) continua restrita. Para além disso, os dados disponíveis não permitem ter uma percepção global de como distintos factores influenciam a composição da carne, desde a sua produção até ao consumo. Neste contexto, a nossa investigação foi desenvolvida estudando o efeito dos regimes alimentares dos animais (pastagem×concentrado), processamento tecnológico da carne após o abate (irradiação) e tratamentos térmicos (fervura, microondas e grelhagem), no perfil lipídico, especialmente nos isómeros do CLA, e no valor nutricional de carne de ruminantes. Foram seleccionadas e caracterizadas 4 carnes tradicionais DOP (Carnalentejana, Mertolenga, Barrosã e Arouquesa). Os resultados sugerem que a gordura intramuscular das carnes de novilho relativamente às de vitela, apresentam menor valor nutricional ao longo do ano, devido ao sistema de produção semi-extensivo utilizado nos novilhos. Por sua vez, a Carnalentejana-DOP apresenta uma qualidade nutricional superior comparativamente à carne de vaca de produção intensiva. No sentido de avaliar em detalhe o efeito de diferentes regimes alimentares no valor nutricional dos lípidos da carne, bem como a sua utilidade como discriminantes químicos da origem da carne, realizou-se um ensaio controlado. Os dados obtidos reforçam os resultados anteriores que sugeriam que a carne de animais de pastoreio apresenta melhor qualidade nutricional (teores mais elevados de n-3 PUFA e CLA) do que a carne de animais alimentados a concentrado. Este facto traduz os efeitos benéficos da pastagem no perfil de ácidos gordos da carne. Relativamente às alterações na composição da gordura intramuscular, resultantes do efeito de processamentos seguintes ao abate, a irradiação, uma tecnologia prospectiva para a conservação das carnes, não promoveu modificações significativas. Os tratamentos térmicos, frequentemente utilizados em culinária, induziram um impacto moderado no perfil dos ácidos gordos, como consequência das perdas de humidade e concentração da gordura. Em resumo, a composição lipídica da gordura intramuscular das carnes de bovino DOP estudadas apresenta um valor nutricional acrescentado para os consumidores, considerando os valores de n-3 PUFA, CLA (total e do isómero c9,t11) e da razão n-6/n-3, contribuindo para a sua diferenciação no mercado.
RESUMO - Contribuição para o estudo da composição lipídica e do valor nutricional da gordura intramuscular na carne de ruminantes - A composição em ácidos gordos e o ácido linoleico conjugado (CLA) são temas actuais de grande interesse, com particular relevância para a qualidade da carne e saúde humana. As carnes de ruminantes têm sido consideradas alimentos pouco saudáveis, principalmente devido à sua fracção lipídica com elevada concentração em ácidos gordos saturados. Contudo, as gorduras edíveis dos ruminantes são a principal fonte natural de isómeros CLA, sendo os isómeros bioactivos (c9,t11 e t10,c12) associados a propriedades potencialmente benéficas para a saúde humana. Em Portugal, a informação científica disponível para apoiar a qualidade e a reputação da carne bovina de raças autóctones criadas segundo as especificações de Denominação de Origem Protegida (DOP) continua restrita. Para além disso, os dados disponíveis não permitem ter uma percepção global de como distintos factores influenciam a composição da carne, desde a sua produção até ao consumo. Neste contexto, a nossa investigação foi desenvolvida estudando o efeito dos regimes alimentares dos animais (pastagem×concentrado), processamento tecnológico da carne após o abate (irradiação) e tratamentos térmicos (fervura, microondas e grelhagem), no perfil lipídico, especialmente nos isómeros do CLA, e no valor nutricional de carne de ruminantes. Foram seleccionadas e caracterizadas 4 carnes tradicionais DOP (Carnalentejana, Mertolenga, Barrosã e Arouquesa). Os resultados sugerem que a gordura intramuscular das carnes de novilho relativamente às de vitela, apresentam menor valor nutricional ao longo do ano, devido ao sistema de produção semi-extensivo utilizado nos novilhos. Por sua vez, a Carnalentejana-DOP apresenta uma qualidade nutricional superior comparativamente à carne de vaca de produção intensiva. No sentido de avaliar em detalhe o efeito de diferentes regimes alimentares no valor nutricional dos lípidos da carne, bem como a sua utilidade como discriminantes químicos da origem da carne, realizou-se um ensaio controlado. Os dados obtidos reforçam os resultados anteriores que sugeriam que a carne de animais de pastoreio apresenta melhor qualidade nutricional (teores mais elevados de n-3 PUFA e CLA) do que a carne de animais alimentados a concentrado. Este facto traduz os efeitos benéficos da pastagem no perfil de ácidos gordos da carne. Relativamente às alterações na composição da gordura intramuscular, resultantes do efeito de processamentos seguintes ao abate, a irradiação, uma tecnologia prospectiva para a conservação das carnes, não promoveu modificações significativas. Os tratamentos térmicos, frequentemente utilizados em culinária, induziram um impacto moderado no perfil dos ácidos gordos, como consequência das perdas de humidade e concentração da gordura. Em resumo, a composição lipídica da gordura intramuscular das carnes de bovino DOP estudadas apresenta um valor nutricional acrescentado para os consumidores, considerando os valores de n-3 PUFA, CLA (total e do isómero c9,t11) e da razão n-6/n-3, contribuindo para a sua diferenciação no mercado.
This work was co-financed by Centro de Investigação Interdisciplinar em Sanidade Animal (Project CIISA/52.Carne-Bioactivos) da Faculdade de Medicina Veterinária da Universidade Técnica de Lisboa and Fundação para a Ciência e a Tecnologia (POCTI/CVT/2002/44750) and Ministério da Agricultura (AGRO/2003/512).
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Potu, Ramesh Babu. "THE EFFECT OF LIPID SUPPLEMENTS ON THE POPULATION OF SELECTED RUMINAL BACTERIA VARIES WITH THE FATTY ACID COMPOSITION." OpenSIUC, 2009. https://opensiuc.lib.siu.edu/theses/67.
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There is an increasing body of evidence that conjugated linoleic acid (c9t11 CLA) suppresses chemically induced tumor development in cell cultures and animal models. Ruminant-derived foods make a major contribution to total fat consumption and are the main source of c9t11 CLA in the human diet. In light of the potential benefits to long-term human health, there has been increased interest in enhancing the concentrations of potentially beneficial fatty acids (FA) in milk and meat. Factors affecting c9t11CLA production and secretion into milk fat have been extensively studied the last 10 years and a large pool of knowledge has accumulated. However, little information is currently available about the effects of feeding c9t11 CLA- stimulating diets on rumen microbial ecology, particularly, bacterial species believed to be involved in the biohydrogenation (BH) process. The main objective of this study was to evaluate the effect of lipid source on the DNA concentrations of selected ruminal bacteria. Four continuous culture fermenters were used in 4 x 4 Latin square design with four periods of 10 d each. Treatment diets were fed (45 g/d DM basis) in three equal portions during the day. The diets were 1) control diet (50% alfalfa pellets, 50% concentrate, CON), 2) CON plus saturated fat (rumofat; SAT), 3) CON plus soybean oil (SBO), and 4) CON plus fish oil (FO). Lipid supplements were added at 3% of diet DM. Lipid supplements had no effect on feed digestibility, total VFA and acetate concentrations or fermenter pH. Propionate concentration was higher with the FO diet in comparison with the other treatment diets. Butyrate concentration was similar between the SBO and FO diets and both were lower than the levels for the CON and SAT diets. The concentration of VA in effluents increased with SBO and FO diets and was highest with SBO diet. The concentrations of C18:0 in effluents were lowest for the FO diet compared with the other treatment diets. The concentrations of c9t11 CLA in effluents were similar between SBO and FO diets and both were higher than levels for the CON and SAT diets. Concentrations of DNA for total bacteria, A. lipolytica, C. proteoclasticum and S. dextrinosolvens were similar for all diets. The concentrations of B. fibrisolvens (69.1 pg/45ng total DNA) and R. albus (1.96 pg/45ng total DNA) were least with the FO diet but were similar among the other treatment diets (SAT-104.2; 5.4, SBO-121.2; 5.71, and CON-126.3; 5.17 pg/45ng total DNA). S. ruminantium DNA concentration was highest with the FO diet and was least with the SAT diet (177.5, 54.9, 75.5, and 691.1 pg/20ng total DNA for treatment diets 1 to 4, respectively). In conclusion, SBO had no effect on bacterial DNA concentrations tested in this study and the inhibitory effects of FO on BH may be due in part to its influence on B. fibrisolvens, R. albus and S. ruminantium.
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Strömstedt, Adam A. "Antimicrobial Peptide Interactions with Phospholipid Membranes : Effects of Peptide and Lipid Composition on Membrane Adsorption and Disruption." Doctoral thesis, Uppsala universitet, Institutionen för farmaci, 2009. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-100966.
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The interactions between antimicrobial peptides and phospholipid membranes were investigated, in terms of lipid headgroup variations and the role of cholesterol, as well as peptide composition and structure. Also strategies for increasing proteolytic stability were evaluated. The interactions were studied on model membranes in the form of liposomes and supported bilayers, through a combination of ellipsometry, fluorescence spectroscopy, circular dichroism, dynamic light scattering, electrophoresis, electron cryomicroscopy, and bacterial/cell culture experiments. The findings showed that membrane tolerance against the lytic activity of melittin, was increased on anionic membranes by electrostatic arrest in the headgroup region, and was reduced by hydration repulsion. The presence of cholesterol caused a reduction in melittin adsorption, while at the same time reducing membrane tolerance per adsorbed peptide. Differences in membrane leakage mechanisms were also attributed to cholesterol, where large scale structural effects contributed to the leakage, while other membranes followed the pore formation model. Substituting specific amino acids for tryptophan on an LL-37 derivative, was shown to increase stability against bacterial proteases, while at the same time significantly increasing antibacterial properties. These substitutions, as well as terminal modifications, increased adsorption and membrane lytic properties in a way that was less dependent on electrostatics. Furthermore, by comparing short cationic peptides with oligotryptophan end-tagged versions, the lytic mechanism of end-tagged peptides, and the different contributions of arginine and lysine to membrane adsorption and disruption were demonstrated. This thesis is a contribution to the development of antimicrobial peptides as therapeutic alternatives to conventional antibiotics.
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Burkhardt, Jonathan. "Homology modeling of bovine rhodopsin investigation of the effect of lipid composition and equilibration on predicted structure /." Cincinnati, Ohio : University of Cincinnati, 2005. http://www.ohiolink.edu/etd/view.cgi?acc%5Fnum=ucin1131483101.
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Cole, Rachel M. "The effects of fermented soy and soy diets on hepatic lipid composition in zucker (fa/fa) rats." Connect to resource, 2006. http://hdl.handle.net/1811/6601.
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Thesis (Honors)--Ohio State University, 2006.Title from first page of PDF file. Document formatted into pages: contains 26 p.; also includes graphics. Includes bibliographical references (p. 23-26). Available online via Ohio State University's Knowledge Bank.