Polyunsaturated Fatty Acids In Lipids Research Articles

Knockout of a PLD gene in Schizochytrium limacinum SR21 enhances docosahexaenoic acid accumulation by modulation of the phospholipid profile

BackgroundThe hydrolysis and transphosphatidylation of phospholipase D (PLD) play important roles in the interconversion of phospholipids (PLs), which has been shown to profoundly impact lipid metabolism in plants. In this study, the effect of the PLD1 gene of Schizochytrium limacinum SR21 (S. limacinum SR21) on lipid metabolism was investigated.ResultsPLD1 knockout had little impact on cell growth and lipid production, but it significantly improved the percentage of polyunsaturated fatty acids in lipids, of which docosahexaenoic acid (DHA) content increased by 13.3% compared to the wild-type strain. Phospholipomics and real-time quantitative PCR analysis revealed the knockout of PLD1 reduced the interexchange and increased de novo synthesis of PLs, which altered the composition of PLs, accompanied by a final decrease in phosphatidylcholine (PC) and an increase in phosphatidylinositol, lysophosphatidylcholine, and phosphatidic acid levels. PLD1 knockout also increased DHA content in triglycerides (TAGs) and decreased it in PLs.ConclusionsThese results indicate that PLD1 mainly performs the transphosphatidylation activity in S. limacinum SR21, and its knockout promotes the migration of DHA from PLs to TAGs, which is conducive to DHA accumulation and storage in TAGs via an acyl CoA-independent pathway. This study provides a novel approach for identifying the mechanism of DHA accumulation and metabolic regulation strategies for DHA production in S. limacinum SR21.

Swine digestate treatment by prior nitrogen-starved Chlorella vulgaris: The effect of over-compensation strategy on microalgal biomass production and nutrient removal

Anaerobic digester effluent containing high levels of ammonia poses a threat to the environment. To hinder this issue, a modern and promising treatment method incorporates both microalgae and their bioconversion potential. When culturing Chlorella vulgaris at a 1:7 digestate supernatant dilution ratio, biomass concentration was 1.33 g L−1 and 66% of ammonia nitrogen was removed. Furthermore, a prior nitrogen-starved seed method, namely over-compensation strategy, was applied to improve both biomass production and nutrient removal. By using nitrogen-starved seeds after a 48 h nitrogen-free stimulation, biomass yield increased by 1.7-times to 2.56 g L−1. Simultaneously, ammonia nitrogen and total phosphorus removal efficiencies reached 99% and 97% respectively. The enhanced production corresponds to higher chlorophyll fluorescence in the middle and late stages of the culture. In addition, the bioproduct contained 39% carbohydrates, and the proportion of polyunsaturated fatty acids in lipids was 66%. These findings demonstrated that the over-compensation strategy contributed to greater nitrogen removal and high-value bioproduct production in the microalgae-digestate treatment system.

Spleen Oxylipin and Polyunsaturated Fatty Acid Profiles are Altered by Dietary Source of Polyunsaturated Fatty Acid and by Sex.

As the largest secondary lymphoid organ, the spleen plays an important role in immune responses. The role of arachidonic acid (ARA) and its 20-carbon eicosanoids in modulating immune function has long been of interest. However, recent advances have enabled the identification of numerous other n-6 and n-3 polyunsaturated fatty acid (PUFA)-derived oxylipins. Here, we investigate the effects of diet and sex on the spleen nonesterified oxylipin profiles and phospholipid and neutral lipid PUFA composition in Sprague-Dawley rats supplemented with oils rich in α-linolenic acid (ALA), eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA), or linoleic acid. Dietary ALA, EPA, and DHA resulted in lower levels of ARA and ARA oxylipins. Oxylipins derived from other n-6 PUFA were also reduced despite no or opposite effect on their PUFA levels. Each diet also resulted in higher levels of oxylipins almost exclusively derived from the supplemented PUFA, despite PUFA in the same biosynthetic pathway also often being increased. Further, while oxylipin differences often reflected changes to phospholipid PUFA, there were instances where they corresponded more closely to changes in neutral lipid PUFA. With respect to sex effects, >50% of lipoxygenase ARA-derived oxylipins were higher in males in at least one diet group, while multiple DHA oxylipins were lower in males only in rats provided the DHA diet. This fundamental description of oxylipin composition in the spleen, including the influence of diet and sex and the relationship to PUFA composition, will help inform future studies examining the functions of these oxylipins under physiological and pathological conditions.

Seed Lipids from Pulmonaria mollis Growing in Several RF Climate Zones

Lipids from seeds of Pulmonaria mollis (Boraginaceae) from two RF climate zones, i.e., Krasnodar Krai (I) and Republic of Bashkortostan (II), were characterized. The neutral lipid (NL) contents of I were greater than those of II (33.8 and 20.5%, respectively). The NL classes were characterized. A larger amount of polyunsaturated fatty acids (PUFAs) concentrated in NL and triacylglycerides (TAGs) from I and II [in NL (%, respectively): 65.6 and 65.0, including α-18:2, 28.8 and 31.9; γ-18:3, 18.5 and 14.5; α-18:3, 12.7 and 14.5; 18:4, 5.7 and 4.1; in TAG (%, respectively): 63.5 and 66.0, including α-18:2, 29.4 and 32.3; γ-18:3, 17.15 and 14.36; α-18:3, 12.5 and 14.6; 18:4, 4.5 and 4.7]. Fractions enriched in PUFAs γ-18:3 (47.1%) and 18:4 (21.2%) were obtained. The ω-6/ω-3 ratios in the lipid PUFAs were 2.7:1-2.2:1.

Dietary ALA from Spinach Enhances Liver n-3 Fatty Acid Content to Greater Extent than Linseed Oil in Mice Fed Equivalent Amounts of ALA.

Although several works have reported absorption rate differences of n-3 polyunsaturated fatty acids (PUFA) bound to different lipid forms, such as ethyl ester, triacylglycerol (TAG), and phospholipids, no studies have investigated the effect of n-3 PUFA from glycolipids (GL). The present study compared the fatty acid contents of tissue and serum lipids from normal C57BL/6J mice fed two types of α-linolenic acid (ALA)-rich lipids, spinach lipid (SPL), and linseed oil (LO). ALA was primarily present as the GL form in SPL, while it existed as TAG in LO. Supplementation of both lipids increased ALA and its n-3 metabolites, eicosapentaenoic acid (EPA), docosapentaenoic acid (DPA), and docosahexaenoic acid, and decreased n-6 PUFA, linoleic acid and arachidonic acid, in the livers, small intestines, and sera of the treated mice compared with those of the control group. When the comparison between the SPL and LO diets containing the same amount of ALA was conducted, the EPA and DPA levels in the liver lipids from mice fed the SPL diet were significantly higher than those fed the LO diet. Additionally, the total contents of n-3 PUFA of lipids from the livers, small intestines, and sera of the SPL group were higher than those of the LO group.

Simultaneous Detection of Low and High Molecular Weight Carbonylated Compounds Derived from Lipid Peroxidation by Electrospray Ionization-Tandem Mass Spectrometry

Reactive oxygen species (ROS) and other oxidative agents such as free radicals can oxidize polyunsaturated fatty acids (PUFA) as well as PUFA in lipids. The oxidation products can undergo consecutive reactions including oxidative cleavages to yield a chemically diverse group of products, such as lipid peroxidation products (LPP). Among them are aldehydes and ketones ("reactive carbonyls") that are strong electrophiles and thus can readily react with nucleophilic side chains of proteins, which can alter the protein structure, function, cellular distribution, and antigenicity. Here, we report a novel technique to specifically derivatize both low molecular and high molecular weight carbonylated LPP with 7-(diethylamino)coumarin-3-carbohydrazide (CHH) and analyze all compounds by electrospray ionization-mass spectrometry (ESI-MS) in positive ion mode. CHH-derivatized compounds were identified by specific neutral losses or fragment ions. The fragment ion spectra displayed additional signals that allowed unambiguous identification of the lipid, fatty acids, cleavage sites, and oxidative modifications. Oxidation of docosahexaenoic (DHA, 22:6), arachidonic (AA, 20:4), linoleic (LA, 18:2), and oleic acids (OA, 18:1) yielded 69 aliphatic carbonyls, whose structures were all deduced from the tandem mass spectra. When four phosphatidylcholine (PC) vesicles containing the aforementioned unsaturated fatty acids were oxidized, we were able to deduce the structures of 122 carbonylated compounds from the tandem mass spectra of a single shotgun analysis acquired within 15 min. The high sensitivity (LOD ∼ 1 nmol/L for 4-hydroxy-2-nonenal, HNE) and a linear range of more than 3 orders of magnitude (10 nmol/L to 10 μmol/L for HNE) will allow further studies on complex biological samples including plasma.

Anaerobic storage of red blood cells.

Anaerobic storage of red blood cells.

The very low density lipoprotein receptor is not necessary for maintaining brain polyunsaturated fatty acid concentrations

Polyunsaturated fatty acids (PUFA), especially docosahexaenoic and arachidonic acids, as well as cholesterol are important for neural development and maintaining brain function. However, in contrast to cholesterol, the brain is unable to synthesize the required amounts of these PUFA de novo and requires a constant supply from plasma. Suggested pools of uptake include plasma unesterified PUFA or the uptake of PUFA-containing lipoproteins via lipoprotein receptors into endothelial cells of the blood brain barrier. Our study tested whether the very low density lipoprotein receptor (VLDLr) is necessary for maintaining brain PUFA and cholesterol concentrations. Moreover, since VLDLr knockout (VLDLr −/−) mice have been reported to have behavioural deficits, this study asked the question whether altered brain PUFA and cholesterol concentrations might be related to these deficits. VLDLr −/− and wild-type mice had ad libitum access to chow. At 7 weeks of age the mice were sacrificed, and the cortex, cerebellum, hippocampus, and the remainder of the brain were isolated for total fatty acid and cholesterol analyses. There were no differences in total lipid PUFA or cholesterol concentrations in any of the four brain regions between VLDLr −/− and wild-type mice. These findings demonstrate that the VLDLr is not necessary for maintaining brain PUFA concentrations and suggest that other mechanisms to transport PUFA into the brain must exist.

Polyunsaturated Fatty Acids Influence Synaptojanin Localization to Regulate Synaptic Vesicle Recycling

The lipid polyunsaturated fatty acids are highly enriched in synaptic membranes, including synaptic vesicles, but their precise function there is unknown. Caenorhabditis elegans fat-3 mutants lack long-chain polyunsaturated fatty acids (LC-PUFAs); they release abnormally low levels of serotonin and acetylcholine and are depleted of synaptic vesicles, but the mechanistic basis of these defects is unclear. Here we demonstrate that synaptic vesicle endocytosis is impaired in the mutants: the synaptic vesicle protein synaptobrevin is not efficiently retrieved after synaptic vesicles fuse with the presynaptic membrane, and the presynaptic terminals contain abnormally large endosomal-like compartments and synaptic vesicles. Moreover, the mutants have abnormally low levels of the phosphoinositide phosphatase synaptojanin at release sites and accumulate the main synaptojanin substrate phosphatidylinositol 4,5-bisphosphate at these sites. Both synaptobrevin and synaptojanin mislocalization can be rescued by providing exogenous arachidonic acid, an LC-PUFA, suggesting that the endocytosis defect is caused by LC-PUFA depletion. By showing that the genes fat-3 and synaptojanin act in the same endocytic pathway at synapses, our findings suggest that LC-PUFAs are required for efficient synaptic vesicle recycling, probably by modulating synaptojanin localization at synapses.

Effect of feeding supplemental copper on performance, fatty acid profile and on cholesterol contents and oxidative stability of meat of rabbits

One hundred and four rabbits, five weeks old at the beginning of the experiment, were divided into four groups according to a feed additive treatment. Rabbits of the 1st, 2nd, 3rd and 4th group were fed a basal granulated feed (control), basal feed supplemented with CuSO4 · 5H2O at 50mg Cu · kg‐1, basal feed supplemented with 150mg Cu · kg‐1, and the latter feed supplemented with 100mg · kg‐1 vitamin E, respectively. The duration of the experiment was 42 days. Addition of Cu at 150mg · kg.‐1 increased weight gain non‐significantly by 9.1%. This effect was the most pronounced in the first two weeks of fattening. The lowest mortality was observed in rabbits fed the highest amount of additives (7.7% vs. 19.2% in the control). Rabbits were slaughtered at the age of 11 weeks. Neither treatment influenced proportions of saturated, monounsaturated and polyunsaturated fatty acids in lipids extracted from the loin and hindleg muscles. In rabbits fed the highest amount of copper and vitamin E, the cholesterol concentration was significantly decreased by 13.6% and 17.9% in the loin and hindleg meat, respectively. Effects of Cu added at 50mg · kg‐1 were marginal. Copper had no effect on the oxidative stability of meat, measured as thiobarbituric acid‐reactive substances in meat stored at 4°C for 0, 3 and 8 days. Vitamin E added in excess of nutritional requirement improved the oxidative stability of meat. In copper‐fed rabbits, Cu accumulated in the liver, but not in muscles. Feeding of the basal feed for 7 days to rabbits previously fed copper sulphate decreased the hepatic Cu concentration by 14.0 to 24.4%

Effects of dietary polyunsaturated fatty acid/vitamin E (PUFA/tocopherol ratio on antioxidant defence mechanisms of juvenile gilthead sea bream (Sparus aurata L., Osteichthyes, Sparidae)).

Lipid peroxidation, specifically polyunsaturated fatty acid (PUFA) oxidation is highly deleterious, resulting in damage to cellular biomembranes, and may be a principal cause of several diseases in fish including jaundice and nutritional muscular dystrophy. Tissue lipid PUFA content and composition are critical factors in lipid peroxidation, as is the level of endogenous antioxidant molecules such as vitamin E. The primary objective of the present study was the characterization of antioxidant systems in a cultured juvenile marine fish, gilthead sea bream (Sparus aurata) with the underlying aim to understand how to avoid oxidation problems that may cause pathologies and disease and so to enhance growth and quality of early ongrowing stages. Juvenile sea bream were fed diets having either high or low levels of fish oil and supplemented or basal levels of vitamin E with PUFA/vitamin E ratios ranging from 117±12 in the diet with low PUFA supplemented with vitamin E to 745±48 in the diet with high PUFA with no additional vitamin E. None of the diets had serious deleterious effects on growth or survival of the fish, but the different dietary regimes were effective in significantly altering the PUFA/vitamin E ratios in the fish livers with values ranging from 5.7±0.4 in fish fed the diet with low PUFA supplemented with vitamin E to 91.1±13.2 in fish fed the diet with high PUFA with no additional vitamin E. This had effects on the peroxidation status of the fish as indicated by the significantly altered levels of in vivo lipid peroxidation products measured in liver, with fish fed the diet rich in PUFA and low in vitamin E showing significantly higher values of thiobarbituric acid reactive substances (TBARS) and isoprostanes. The isoprostane levels generally followed the same pattern as the TBARS levels supporting its value as an indicator of in vivo oxidative stress in fish, as it is in mammals. However, few significant effects on antioxidant enzyme activities were observed suggesting that more severe conditions may be required to affect these activities such as increasing the PUFA/vitamin E ratio or by increasing peroxidative stress through the feeding of oxidized oils.

Assignment of mono‐ and polyunsaturated fatty acids in lipids of tissues and body fluids

Semi-selective 800 MHz 1H, 13C HSQC NMR spectra provide ultra-high resolution of the double bond region of lipid spectra and the possibility of assigning signals to individual unsaturated fatty acid side-chains such as 18:1, 18:2 or 20:4 even in complex mixtures such as biofluids. Additional HSQC-TOCSY spectra correlate the direct double bond signals with the adjacent allylic high-field proton signals of mono- and polyunsaturated fatty acids. These signals show characteristic chemical shifts to differentiate unsaturated fatty acids such as 18:1, 18:2 and 20:4 (or others). By this means, the amount of each type of unsaturated fatty acid can be quantified. Typical lipid spectra of body fluids (blood plasma and cerebrospinal fluid) and pig brain (grey and white matter) are presented and discussed with respect to the use of this technique for diagnostic purposes. © 1998 John Wiley & Sons, Ltd.

Assignment of mono- and polyunsaturated fatty acids in lipids of tissues and body fluids

Semi-selective 800 MHz 1H, 13C HSQC NMR spectra provide ultra-high resolution of the double bond region of lipid spectra and the possibility of assigning signals to individual unsaturated fatty acid side-chains such as 18:1, 18:2 or 20:4 even in complex mixtures such as biofluids. Additional HSQC-TOCSY spectra correlate the direct double bond signals with the adjacent allylic high-field proton signals of mono- and polyunsaturated fatty acids. These signals show characteristic chemical shifts to differentiate unsaturated fatty acids such as 18:1, 18:2 and 20:4 (or others). By this means, the amount of each type of unsaturated fatty acid can be quantified. Typical lipid spectra of body fluids (blood plasma and cerebrospinal fluid) and pig brain (grey and white matter) are presented and discussed with respect to the use of this technique for diagnostic purposes. © 1998 John Wiley & Sons, Ltd.

The effect of monospecific algal diets on growth and fatty acid composition of Pecten maximus (L.) larvae

Four batches of Pecten maximus (L.) larvae were grown under hatchery conditions and fed the monospecific diets Pavlova lutheri Droop, Isochrysis aff. galbana Green (clone T-iso; termed Tahitian Isochrysis), Chaetoceros calcitrans Takano and Dunaliella tertiolecta Butcher which were selected on their very different polyunsaturated fatty acid (PUFA) profiles. Neutral and polar lipid PUFA compositions of larvae were influenced by diets. The constant level of ( n-3) PUFA in neutral lipids of larvae although very different in the diet indicated that neutral lipid composition was partially controlled by the larval metabolism. Similarly, the stability of total saturated, monounsaturated and PUFA levels (25, 15 and 55% of total fatty acids), as well as total ( n-3) PUFA level and the preferential incorporation of the 22:6( n-3) in polar lipids clearly indicated a metabolic regulation of the fatty acid composition. The 20:4( n-6) and 22:5( n-6) acids were also preferentially incorporated. The accumulation of 18:3( n-3) or 20:5( n-3) with depletion of 22:6( n-3) in neutral and polar lipids of larvae fed diets with high levels of the first two fatty acids but little or no 22:6( n-3), indicated that elongation-desaturation of dietary fatty acids was too low in P. maximus larvae to maintain high 22:6( n-3) levels in polar lipids. The selective incorporation of dietary long chain PUFA into neutral and polar lipids by acyltransferases may be the main mechanism controlling the fatty acid composition of larvae. These results indicate that P. maximus larvae have essential requirements for long chain ( n-3) and ( n-6) PUFA, similar to many other marine species.

N-3 Polyunsaturated Fatty Acids in Lipids of Ascidian Halocynthia roretzi.

The fatty acid composition of the edible ascidain Halocynthia roretzi was studied by means of open-tubular GLC with medium polarity phase Silar-5CP. About fifty components were ob-served, and their distribution among neutral and polar lipids was compared. The main fatty acids were found to be 14:0, 16:0, 16:1 (n-7), 18:0, 18:1 (n-9), 18:1 (n-7), 18:4 (n-3), 20:3 (n-3), 20:5 (n-3), and 22:6 (n-3). In monoenes, (n-7) series fatty acids were predominant, while nine tenths of the polyenoic fatty acids were represented by (n-3) series fatty acids, mainly eicosapen-taenoic. The literature data obtained by packed column GLC were compared with those obtained in the present investigation.

Effect of portal-systemic shunting on the plasma lipid polyunsaturated fatty acid (PUFA) content in liver cirrhosis (LC)

Effect of portal-systemic shunting on the plasma lipid polyunsaturated fatty acid (PUFA) content in liver cirrhosis (LC)

Changes in fatty acid composition in sardines (Sardinops melanosticta) with cooking and refrigerated storage.

The influence of cooking and later storage in a refrigerator for 7 days on the fatty acid composition of lipids in sardines (Sardinops melanosticta) was studied. The total lipid and triacylglycerol (TG) levels did not change and the phospholipid (PL) level decreased somewhat with cooking or during storage. The fatty acid composition of the total lipids and TG fractions was little changed and that in the PL fractions was somewhat changed by the cooking. The composition of the polyunsaturated fatty acids (PUFA) in lipids of sardine precooked at 100 or 170 degrees C for 30 min changed from 42.7 to 38.3 or 33.5%, respectively, for total lipids and from 51.5 to 38.4 or 37.6%, respectively, for PL fractions during storage. The fatty acids in lipids from the ordinary meat of sardine was stable and those in the dark meat were extremely unstable during storage after cooking. We concluded that the PUFA in the lipids of sardines were stable to cooking, but unstable to oxidation during storage in a refrigerator. The PUFA of lipids in the dark meat of sardine were extremely unstable to oxidation.

Polyunsaturated fatty acids and protection of newborn rats from oxygen toxicity

To test whether polyunsaturated fatty acids (PUFA) might be associated with protection against oxygen toxicity in newborn experimental animals, we performed two series of experiments. In the first series, adult female rats were fed one of three diets--regular Rat Chow, a high-PUFA (safflower oil-based) diet, or a low-PUFA (palm oil-based) diet--for several weeks before and throughout pregnancy and lactation. Newborn offspring of the three diet groups had similar antioxidant enzyme activities and surfactant development. Offspring of dams fed the high-PUFA diet had total lung lipid fatty acids characterized by increased linoleic acid (18:2 omega 6) and arachidonic acid (20:4 omega 6) and a significantly increased PUFA/saturated fatty acid ratio, compared with offspring of dams fed the regular diet or low-PUFA diet; associated with this increased PUFA pattern was markedly superior survival (80 of 84 (95%) vs 56 of 84 (67%) for regular-diet offspring, P less than 0.01) after 7 days in greater than 95% oxygen. Conversely, offspring born to dams fed the low-PUFA diet had decreased lung PUFA content and inferior tolerance to prolonged high O2 exposure (survival 38 of 84 (45%)). In the second experimental series, the postnatal provision of high PUFA rat milk to offspring born to dams fed the low-PUFA diet (via "cross-nurturing" by high-PUFA diet dams) rapidly increased their lung lipid PUFA and improved their hyperoxic survival (44 of 50 vs 25 of 50 for low-PUFA diet newborn animals kept with their low-PUFA mother rats, P less than 0.01). These studies suggest that increasing lung lipid PUFA can confer a protective effect against the toxic effects of hyperoxia on the newborn animal lung.

Effect of Nitrite on Lipid Degradation During Storage of Cooked Pork Meat

Ground lean pork was stored for six days at 4°C after cooking to an internal temperature of 75°C in the presence of 150ppm sodium nitrite. Nitrite prevented the oxidative breakdown of lipids during storage, as measured by the TBA test, lipid fluorescence, lipid phosphorus content, total phospholipid fatty acids and polyunsaturated fatty acids (PUFAs) in phospholipids. Neither storage nor nitrite treatment affected the triglycerides. Nitrite also prevented the formation of an unidentified lipid compound during storage. Cooking caused a large decrease in polar lipid PUFAs content and, with nitrite, prevented the increase in TBA numbers and lipid fluorescence but did not prevent the decrease in levels of polar lipid PUFAs; nitrite inhibited the breakdown of intermediate products of oxidation without delaying the initial steps in PUFA oxidation. Increase of free fatty acid (FFA) content, relatively high levels of PUFAs in this fraction, and decrease in FFA-PUFAs during storage of the nitrite treated samples suggest that FFAs are important intermediates in the oxidative degradation of the polar lipids. Lipid fluorescence showed the same trend as TBA Numbers as a measure of PUFA oxidation.

Lethal and mutagenic effects of malondialdehyde, a decomposition product of peroxidized lipids, on Escherichia coli with different DNA-repair capacities

Lipid peroxidation, a chain reaction of oxidative deterioration of polyunsaturated fatty acids in lipids, has been implicated as a basic deteriorative reaction in various kinds of oxidative damage in living organisms. However, the relationship of lipid peroxidation to carcinogenesis remains tenuous. Recent studies have shown that there is a satisfactory correlation between mutagenesis and carcinogenesis. To clarify the relationship of lipid peroxidation to carcinogenesis, we attempted to examine the molecular characteristics, the repair mechanisms and the expression of mutations of DNA damage induced by lipid peroxides, secondary breakdown products and radicals produced during decomposition of lipid peroxides in Escherichia coli. The experiments dealt with the effect of malondialdehyde (MDA), one of the most important products of lipid peroxidation. In an E. coli mutagenesis system, we found that MDA is mutagenic in cells having active DNA-repair systems. The UvrB − and RecA − derivatives, however, are not mutable by the MDA treatment. The lethal action of MDA on the latter strains, however, is increased. These findings suggest that MDA induces interstrand cross-linking as can be deduced from the following experiments in vitro. (1) The reaction of MDA with DNA resulted in the formation of fluorescent products. The structure of the fluorescent chromophore — a conjugated amino-imino-propene compound — indicated that 1 mole of MDA reacts with 2 moles of amino groups present in DNA bases. (2) Heat-denaturation of native DNA resulted in a decrease in the yield of the fluorescent products. (3) The yield of the fluorescent products was also reduced by the pretreatment of DNA with mitomycin C. Therefore, it seems possible that lipid peroxidation leads to cellular mutagenesis, through DNA damage — such as by the fluorescent products induced by reaction with MDA.