Rapid dioxin assessment in fish products by fatty acid pattern recognition

A novel, cost- and time-effective dioxin screening method relying on fatty acid profile was developed for fish products. The method is based on multivariate covariance between fatty acid composition and dioxin. A dioxin range varying from 1.1 to 47.1 ng TEQ-WHO kg fat(-1) was investigated using 64 fish meal samples. An optimal multivariate dioxin prediction model was developed based on reduction from the original 32 to 13 fatty acids, thus increasing the parsimony and the robustness of the model. The model obtained with three partial least squares regression (PLS) components included the following 13 fatty acids: C14:1 n-5, C16:4 n-1, C18:1 n-9, C18:2 n-6, C18:3 n-6, C18:3 n-3, C20:0, C20:1 n-9, C20:4 n-6, C20:3 n-3, C22:1 n-7, C22:6 n-3, C24:1 n-9. Considering the whole investigated dioxin range, the performance of the PLS model based upon full cross-validation yielded a correlation of 0.90 (r(2)) and a prediction error of 3.31 ng PCDD/F TEQ-WHO kg fat(-1). A submodel of samples in the lower dioxin range 1 to 15 ng PCDD/F TEQ-WHO kg fat(-1) returned a r(2) of 0.88 and an error of 1.85 ng PCDD/F TEQ-WHO kg fat(-1).     

Congener profile and toxicity assessment of polychlorinated biphenyls in human adipose tissue of Italians and Chileans

Human exposure to polychlorobiphenyls (PCBs) in humans was determined by analyzing adipose tissue samples collected in 1996–1997 from two different localities: Siena (Italy) and Concepción (Chile). ΣPCBs was higher in Italian samples than that from Chile (493 and 53 ng/g wet wt., respectively). Thirty-seven different PCB congeners were identified in all samples. The prevailing PCB congeners in both groups were 22′44′5 pentachlorobiphenyl (IUPAC no. PCB 118), 22′344′5′ (PCB-138) and 22′44′55′ (PCB-153) hexachlorobiphenyls and 22′33′44′5 (PCB-170), 22′344′55′ (PCB-180) and 22′34′55′6 (PCB-187) heptachlorobiphenyls. PCB-153 accounted for more than 20% of the total PCB residue in both groups, while the remaining six congeners accounted for approximately 70%. Hexachlorobiphenyls were the most abundant congeners in all samples, with 42% of total residue in those from Italy and 43% in the Chilean samples, followed by heptachlorobiphenyls with 41 and 36% in Italian and Chilean samples, respectively. Average concentrations of non-ortho substituted coplanar congeners were below 1 pg/g wet wt. In the samples from Siena no noticeable differences were observed between the three average coplanar concentrations, while in those from Concepción 33′44′tetrachlorobiphenyl (PCB-77) was much higher than 33′44′pentachlorobiphenyl (PCB-126) and 33′44′55′hexachlorobiphenyl (PCB-169). For each sample the contribution to the total toxic equivalent values (ΣTEQs) of each non-ortho, mono-ortho and di-ortho substituted PCB congeners was assessed. The overall TEQs calculated for the monitored PCBs, were 10.16 pg/g wet wt. in Italian samples and 1.09 pg/g wet wt. in Chileans ones. In both groups the main contribution to ΣTEQs were the di-ortho substituted PCB congeners (Siena: 6.17 pg/g wet wt.; Concepción: 0.56 pg/g wet wt.) and the mono-ortho substituted PCB congeners (Siena: 3.97 pg/g wet wt.; Concepción: 0.50 pg/g wet wt.).     

Supplemental Feeding of Laying Hens with Wood Vinegar to Decrease the Ratio of n-6 to n-3 Fatty Acids in Eggs

A balanced ratio of fatty acids n-6 to n-3 in chicken eggs is important for health and to help prevent and manage obesity and other diseases. Traditionally, fish oil or flax seed has been utilized as feed additives to decrease the ratio of n-6 to n-3(n-6:n-3) fatty acids in eggs. The hull of spina date seed(HSDS) is a common agricultural waste product in China, from which wood vinegar(HSDSWV) may be derived. This study evaluated HSDSWV as a supplement in hen feeds to improve the quality of eggs and decrease the ratio of fatty acids n-6:n-3. HSDSWV was obtained via carbonization, and refined. Six concentrations(nil to 0.5%) of HSDSWV were prepared and fed to 6 hen groups, respectively, for 50 d. The fatty acids of the hen's egg yolks were analyzed by gas chromatography/electron ionization-mass spectrometry(GC/EI-MS) in the selected ion monitoring(SIM) mode. The 0.2% HSDSWV resulted in the best egg yolk quality, with a lower percentage of linoleic acid(C18:2n6) and higher percentages of cis-5,8,11,14,17-eicosapentaenoic acid(C20:5n3) and cis-4,7,10,13,16,19-docosahexaenoic acid(C22:6n3), and thus a lower n-6:n-3 ratio compared with the other HSDSWV concentrations. In addition, the eggs contained higher levels of yolk fat and egg yolk than the controls did. In conclusion, to modify the fatty acid composition of hens' eggs and obtain a balanced ratio of n-6:n-3, 0.2% HSDSWV may be considered suitable as a dietary supplement in hens' feed.     

Microsomal delta 9, delta 6 and delta 5 desaturase activities and liver membrane fatty acid profiles in alcohol-fed rats

In experimentally produced alcoholic fatty liver microsomal fatty acid composition was measured using gas chromatography. The results showed an increase in linoleic acid (18:2, n-6) and hexadecaenoic acid (22:6, n-3) and a decrease in arachidonic acid (20:4, n-6) in alcohol-fed rats. Using high performance liquid chromatographic separation of radiolabelled substrate and products, delta 9, delta 6 and delta 5 desaturase enzymes were assayed. The activity of delta 9 and delta 5 desaturase was decreased in alcohol-fed rats and delta 6 desaturase activity was similar in control and alcohol-fed groups. These results indicated there was no causal relationship between desaturase activity and membrane fatty acid changes. Increased amounts of eicosatrienoic acid (20:3, n-9) in rats fed less than 5% fat were observed in both control and alcohol-fed rats. The results indicated that essential fatty acid deficiency was not due to alcohol consumption.     

Persistent organic pollutants in edible fish: a human and environmental health problem

Many persistent organic pollutants (POPs) pose serious health hazards to both the environment and human. Among these, polychlorobiphenyls (PCBs) are probable human carcinogens and can also pose non-cancer health hazards to intellectual functions and the nervous, immune and reproductive systems. The risks and hazards associated with POP residues in tissues are a function of the dioxin-like compound toxicity and an individual's exposure. Fish consumption might become a serious problem because of bioaccumulation as revealed in many studies worldwide.We report data concerning the accumulation and pattern of hexachlorobenzene (HCB), p,p′-DDE and PCBs in edible tissues of commercial fish species (bluefin tuna Thunnus thynnus, swordfish Xiphias gladius, Atlantic mackerel Scomber scombrus) from Italian Seas and of the Antarctic toothfish Dissostichus mawsoni from the Ross Sea (Antarctica). The species analyzed are part of the human diet. 2,3,7,8-TCDD toxic equivalents (TEQs) and tolerable weekly intake (TWI) were also calculated to evaluate the toxic hazard for the population that include them in their diet.Gaschromatography revealed 0.16±0.24 and 0.4±0.2 ng/g wet wt of HCB in Antarctic toothfish and bluefin tuna, respectively. p,p′-DDE concentrations were 38±29 and 31±38 ng/g wet wt in swordfish and bluefin tuna muscle, respectively, and 0.66±0.57 ng/g wet wt in the Antarctic toothfish. PCBs showed higher concentrations and they were 89±82, 80±86 and 5.2±4.0 ng/g wet wt in the muscle of swordfish, bluefin tuna and Antarctic toothfish, respectively. In Mediterranean fish, the most abundant congeners were the most persistent PCB numbers 153, 138, 180, 118 and 170, which accounted for 51% and 47% of the total PCB residue in tuna fish and swordfish, respectively, and 18% in the Antarctic toothfish. TEQs were 1.97 and 4.65 pg/g wet wt in bluefin tuna muscle and gonads, respectively, and 0.11 pg/g wet wt in Antarctic toothfish. The TEQ weekly intake was calculated and values ranged 197–465 pg_TEQ/week when consuming 100 g of Mediterranean fish and therefore lower than the recommended TWI. Those values were higher (788–1860 pg_TEQ/week) than the recommended TWI, if 400 g of fish/week was consumed (with the exception of Antarctic fish).     

Effects of a high alpha-linolenate and high linoleate diet on hemolysis and lipid peroxidation of rat erythrocytes.

alpha-Linolenic acid (18:3n-3) is known to autoxidize several fold faster than linoleic acid (18:2n-6). Feeding a high alpha-linolenate or a high linoleate diet to rats resulted in significant changes in the n-3/n-6 ratios of 20 and 22 carbon highly unsaturated fatty acids in erythrocytes. However, the rates of hemolysis observed in N2- or O2-atmosphere were similar between the two dietary groups. No significant amounts of conjugated dienes were detected and no measurable changes in the fatty acid compositions were observed during the incubations, indicating that the hemolysis occurred without involving significant lipid peroxidation. When stimulated with a free radical initiator, [2,2'-azobis-(2-amidinopropane)dihydrochloride] (AAPH), hemolysis occurred more rapidly, conjugated dienes formed and unsaturated/saturated ratios of phospholipid fatty acids decreased. However, no statistically significant difference was observed in these parameters of the two dietary groups. These results indicate that hemolysis occurs without involving lipid peroxidation but is accelerated by free radicals through lipid peroxidation, and that the difference in autoxidizabilities of alpha-linolenate and linoleate is not reflected in the rates of hemolysis and autoxidation in rat erythrocytes.     

Estrogen-induced cholestasis results in a dramatic increase of b-series gangliosides in the rat liver

Hepatic ganglioside composition was investigated in normal and cholestatic Wistar rats. Cholestasis was induced by 17alpha-ethinylestradiol (EE; 5 mg/kg body weight s.c. for 18 days). As compared with controls, the EE administration resulted in severe cholestasis, as indicated by biochemical as well as morphological signs. Gangliosides isolated from the liver tissue were separated by TLC, with resorcinol-HCl detection and densitometric evaluation. As compared with controls, the total hepatic lipid sialic acid content in cholestatic rats was increased almost 2-fold (44.3 +/- 15.2 vs 79.1 +/- 9.0 nmol/g wet weight of liver tissue, p < 0.01). This increase was primarily due to the increase of ganglioside GD1a (3.6 +/- 1.0 vs 11.8 +/- 3.0 nmol/g wet weight of liver tissue, p = 0.001), as well as to the enormous up-regulation of b-series gangliosides GD3 (0.08 +/- 0.03 vs 2.0 +/- 1.2 nmol/g wet weight of liver tissue, p = 0.002), GD1b (0.1 +/- 0.06 vs 5.4 +/- 1.6 nmol/g wet weight of liver tissue, p = 0.002) and GT1b (0.06 +/- 0.03 vs 6.4 +/- 2.6 nmol/g wet weight of liver tissue, p = 0.002). As the majority of gangliosides are concentrated in cell membranes, our findings suggest that dramatic increase of b-series gangliosides might contribute to the protection of hepatocytes against the deleterious effects of cholestasis.     

Sample pretreatment method for the determination of polychlorinated biphenyls in bird livers using ultrasonic extraction followed by headspace solid-phase microextraction and gas chromatography-mass spectrometry

A simple and reliable sample methodology based on simultaneous ultrasonic extraction, sulfuric acid clean-up and headspace solid-phase microextraction (SPME)-gas chromatography-mass spectrometry has been developed as an advantageous analytical tool for the determination of seven polychlorinated biphenyl congeners in bird livers at low levels. The influence of several parameters on the efficiency of the proposed method was systematically investigated. The clean-up efficiency of sulfuric acid treatment was tested and compared with those of column chromatography (Flosiril, silica gel and alumina) and solid-phase extraction (SPE) (Supelclean ENVI-Carb cartridge) procedures. The use of sulfuric acid in the clean-up step prior to headspace solid-phase microextraction analysis allows the removal of interfering matrix compounds present in the liver extracts that would otherwise cause severe ionization suppression of the polychlorinated biphenyls (PCBs) during the ionization process. The optimized method had good linearity (R2>0.99) over the range studied (5-500 ng/g wet weight) and showed satisfactory level of precision, with RSD values lower than 10.6%. The obtained relative recoveries ranged between 63 and 94%. The limits of detection (0.06-0.63 ng/g wet weight) were low enough to check for harmful levels of polychlorinated biphenyls in biological samples, and were well below most of the restrictive limits established by European Union regulations. The method was found to be reliable under the operational conditions proposed and was applied successfully to the analysis of individual polychlorinated biphenyls in liver tissues. The results obtained from five bird species from Greece revealed the presence of the target compounds in all samples analyzed, at levels ranging between 0.54 and 39.45 ng/g wet weight.     

Determination of polyfluoroalkyl phosphoric acid diesters, perfluoroalkyl phosphonic acids, perfluoroalkyl phosphinic acids, perfluoroalkyl carboxylic acids, and perfluoroalkane sulfonic acids in lake trout from the Great Lakes region

A comprehensive method to extract perfluoroalkyl carboxylic acids, perfluoroalkane sulfonic acids, perfluoroalkyl phosphonic acids, perfluoroalkyl phosphinic acids, and polyfluoroalkyl phosphoric acid diesters simultaneously from fish samples has been developed. The recoveries of target compounds ranged from 78?% to 121?%. The new method was used to analyze lake trout (Salvelinus namaycush) from the Great Lakes region. The results showed that the total perfluoroalkane sulfonate concentrations ranged from 0.1 to 145?ng/g (wet weight) with perfluorooctane sulfonate (PFOS) as the dominant contaminant. Concentrations in fish between lakes were in the order of Lakes Ontario ≈ Erie > Huron > Superior ≈ Nipigon. The total perfluoroalkyl carboxylic acid concentrations ranged from 0.2 to 18.2?ng/g wet weight. The aggregate mean perfluorooctanoic acid (PFOA) concentration in fish across all lakes was 0.045?±?0.023?ng/g. Mean concentrations of PFOA were not significantly different (p?>?0.1) among the five lakes. Perfluoroalkyl phosphinic acids were detected in lake trout from Lake Ontario, Lake Erie, and Lake Huron with concentration ranging from non-detect (ND) to 0.032?ng/g. Polyfluoroalkyl phosphoric acid diesters were detected only in lake trout from Lake Huron, at levels similar to perfluorooctanoic acid.     

Determination of phospholipid fatty acid and triacylglycerol composition of rat caecal mucosa.

The lipid composition of rat caecal mucosa, including the fatty acid composition of phospholipids and triacylglycerols, has been examined by capillary gas chromatography. Thirty-seven peaks were resolved, ranging in chain length from 12 to 24 carbon atoms. Preliminary identification of fatty acids by comparison with authentic standards was confirmed by gas chromatography-mass spectrometry using electron-impact ionization. The neutral and polar components were examined. Fatty acid methyl esters were quantified in absolute amounts with respect to the percentage of total phospholipid and triacylglycerols. The results show significantly higher levels of 16:0, 18:0, 18:1(n-9), 18:1(n-7), 18:2(n-6) and 20:4(n-6) in phospholipids, and higher levels of 16:0, 18:1(n-9) and 18:2(n-6) in triacylglycerols. On the other hand, analysis of caecal triacylglycerols revealed sn-glycerol-palmitate-oleate-palmitate, sn-glycerol-palmitate-linoleate-palmitate and sn-glycerol-palmitate-linoleate-oleate as major components.     

“永固紫”染料和四氯苯醌中多氯代二苯并二/呋喃的分析

 采用浓硫酸对5种不同来源的四氯苯醌和“永固紫”染料样品进行溶解分散,用甲苯提取和 多层色谱柱纯化,利用同位素稀释法及高分辨气相色谱/质谱 (HRGC/HRMS)联用技术,测定 了其中的多氯代二苯并二/呋喃(PCDD/F)的质量比。结果表明“永固紫”染料及其原料中P CDD/F的质量比异常高,八氯代二苯并二/呋喃(OCDD/F)已达到μg/g级甚至100 μg/g级,七氯代二苯并二/呋喃(HpCDD/F)和六氯代二苯并二/呋喃(HxCDD/F)质量比也达到 ng/g级。所有样 品的毒性当量浓度(TEQ)均已超过10 pg/g的危险水平,是纺织品中PCDD/F的一类重要污染源 。并进一步探讨了PCDD/F的来源。     

Identification of novel n-4 series polyunsaturated fatty acids in a deep-sea clam, Calyptogena phaseoliformis

Novel fatty acids originated from the cold-seep clam Calyptogena phaseoliformis, collected from hydrothermal vents in the Japan Trench at a depth of 6354-6367 m, were determined by using gas chromatography-mass spectrometry analysis of the 4,4-dimethyloxazoline derivatives. The major fatty acids present in the C. phaseoliformis lipids belong to the n-4 family non-methylene interrupted polyunsaturated fatty acids (NMI-PUFA): 20:3n-4,7,15, 20:4n-1,4,7,15, and 21:3n-4,7,16, with significant levels of 20:2n-7,15 and 21:2n-7,16 as non-methylene interrupted n-7 dienes. Compared with the lipids of shallow-water clam Mactra chinensis, which contains photosynthetic n-3 PUFA, such as docosahexaenoic acid and icosapentaenoic acid, C. phaseoliformis might have an intrinsic mechanism in vivo so as to maintain the fluidity of the high-melting fatty acids in the membrane lipids by exogenous n-4 family PUFA adaptation as substitutes. Such special kinds of fatty acids are assimilated by the symbiotic chemosynthetic bacteria, which use geothermal energy and minerals from the cold-seep vents. Its unique fatty acid composition corresponding to the novel n-4 family NMI-PUFA markedly differs from those of the reported lipid compositions of other marine animals, which depend on the marine grazing food chain originating from phytoplankton. Thus, the present findings confirm a perfect and closed novel food chain in the cold-seep bivalve and in its symbionts, which is independent from the photosynthetic food chain.     

Marine macroalgae analyzed by mass spectrometry are rich sources of polyunsaturated fatty acids

Algae from cold water (Canada) and warm water (China) were analyzed for their total lipid content, and for their fatty acid (FA) composition and content. The major findings are that FA from Canadian algae are generally richer in polyunsaturated FA (PUFA), with a higher n-3/n-6 FA ratio, and a higher degree of total unsaturation. The 18 C, 4 double bonds FA (18 : 4 stearidonic acid, morotic acid as synonym) was detected in greater amounts in cold water samples. The high levels of total PUFA, and especially of n-3 FA in Canadian algae, suggests their possible utilizations for nutritional purposes.     

Chemical Characterization,Antiproliferative and Antioxidant Activities of Polyunsaturated Fatty Acid-Rich Extracts from Chlorella sp. S14

Microalgae is a rich source of polyunsaturated fatty acid. This study was conducted to identify and isolate microalgal strain with the potentials for producing polyunsaturated fatty acids (PUFAs) and determine its cytotoxic effect on some cancer cells. The algal strain (Chlorella sp. S14) was cultivated using modified BG-11 media, and algal biomass obtained was used for fatty acid extraction. Gas chromatographic–mass spectrometry was used to identify and quantify the levels of the fatty acid constituents. The total content of monounsaturated fatty acids (1.12%) was low compared to polyunsaturated fatty acids (PUFAs) (52.87%). Furthermore, n-3 PUFAs accounted for (12.37%) of total PUFAs with the presence of α-linolenic acid (2.16%) and cis-11,14,17-eicosatrienoic acid (2.16%). The PUFA-rich extract did not exhibit a cytotoxic effect on normal cells. Treatment with the PUFA-rich extract (150 µg/mL) significantly reduced cell viability in MCF-7 (31.58%) and A549 (62.56%) cells after the 48 h treatment. Furthermore, treatment of MCF-7 with fatty acid extracts (125 and 150 µg/mL) showed a significant reduction in MDA levels, increase in catalase activities and decrease in GSH level compared to untreated cells. However, a slight decrease in MDA level was observed in A549 cells after the 48 h treatment. There are no significant changes in catalase activities and GSH level in treated A549 cells. However, a slight reduction of NO levels was observed in treated MCF-7 and A549 cells. These results indicate the potentials of PUFA-rich extracts from Chlorella sp. S14 to reduce viability and modulate redox status in A549 and MCF-7 cells.     

Compositional Study of Phospholipids from the Dried Big Head and Opossum Shrimp,Mussel, and Sea Cucumber Using 31P NMR Spectroscopy: Content and Fatty Acid Composition of Plasmalogen

Herein, we present a qualitative and quantitative analysis of the compositions of plasmalogens and phospholipids (PLs) in dried big head shrimp (Solenocera melantho), opossum shrimp (Neomysis awatschensis), mussel (Mytilus galloprovincialis), and sea cucumber (Apostichopus japonicus). We also analyze the fatty acid composition of the extracted lipids, phosphatidyl choline (PtdCho), and plasmalogen choline (PlsCho) from each sample. In big head shrimp, opossum shrimp, and mussel, phosphatidyl choline (PtdCho) was the most abundant PL at 1677.9, 1603, and 1661.6 mg/100 g of dried sample, respectively, whereas the most abundant PL in sea cucumber was PlsCho (206.9 mg/100 g of dried sample). In all four samples, plasmalogen ethanolamine (PlsEtn) was higher than phosphatidyl ethanolamine (PtdEtn). The content (mg/100 g of dried sample) of PlsCho was highest in mussel (379.0), and it was higher in big head shrimp (262.3) and opossum shrimp (245.6) than sea cucumber (206.9). The contents (mg/100 g of dried sample) of PlsEtn were in the order of mussel (675.4) > big head shrimp (629.5) > opossum shrimp (217.9) > sea cucumber (51.5). For analyzing the fatty acids at the sn-2 position of PlsCho, the consecutive treatment with phospholipase A₁, solid phase extraction, thin-layer chromatography (TLC), and GC-FID were applied. The most abundant fatty acid was eicosapentaenoic acid (EPA, C20:5, n-3) in big head shrimp and sea cucumber, palmitoleic acid (C16:1, n-7) in opossum shrimp, and docosadienoic acid (C22:2, n-6) in mussel.     

Controlled release of 4-hydroperoxycyclophosphamide from the fatty acid dimer-sebacic acid copolymer

Controlled polymeric release of chemotherapeutic agents has shown promise in the management of malignant gliomas. 4-Hydroperoxycyclophosphamide (4HC), loaded on the fatty acid dimer–sebacic acid copolymer (FAD:SA, 1:1), significantly prolonged survival in rats implanted with F98 and 9L gliomas. Here, we studied the in vitro and in vivo release kinetics in phosphate-buffered saline and rat brain of 20% 4HC/FAD:SA (wt:wt), the optimal dose for treatment of rat gliomas. In vitro release under infinite sink conditions was steady over the initial 12 hr to a peak of 20–35% of impregnated drug, consistent with early phase control via surface erosion. Release over the next 3 weeks was minimal, consistent with barrier formation around the polymer by an oily fatty acid dimer degradation product and consequent slowing of release. However, the polymer started to disintegrate by day 4, and there were minimal visible remnants by 3 weeks. Thus, a considerable amount of polymer-carried drug was probably lost in the disintegrating fragments. Also, drug loss is expected from its inherent hydrolytic instability. In vivo release into brain revealed two peak levels of drug at 0–1 hr and 5–20 days. With loaded polymer implanted intraperitoneally or cyclophosphamide injected systemically, peak brain drug levels were measured in 2–8 hr, with substantial decrease by 48 hr without a second peak. Brain levels were substantially higher than blood levels at all time periods. We conclude that FAD:SA (1:1) adequately protects the otherwise labile 4HC, allowing effective and substained drug release in vivo. Furthermore, it should be possible to modify the polymer to adjust the time of peak release for more beneficial therapeutic effects.     

Effects of UV Radiation and Diet on Polyunsaturated Fatty Acids in the Skin,Ocular Tissue and Dorsal Muscle of Atlantic Salmon (Salmo salar) Held in Outdoor Rearing Tanks

The effect of UV radiation (UVR) on juvenile Atlantic salmon (Salmo salar) was assessed by measuring the fatty acid (FA) profiles of muscle, dorsal and ventral skin, and ocular tissues following 4-month long exposures to four different UVR treatments in outdoor rearing tanks. Fish were fed two different diets (Anchovy- and Herring-oil based) that differed in polyunsaturated fatty acid (PUFA) concentrations. Anchovy-fed salmon had higher concentrations of ALA (alpha-linoleic acid; 18:3n-3), EPA (eicosapentaenoic acid; 20:5n-3) and DPA (docosapentaenoic acid, 22:5n-3) in their muscle tissues than fish fed the Herring feed. Fish subjected to enhanced UVB levels had higher concentrations of LIN (linolenic acid, 18:2n-6) and ALA, total omega-6 FA and SAFA (saturated fatty acids) in their tissues compared with fish in reduced UV treatments. Concentrations of ALA, LIN, GLA (gamma-linolenic acid; 18:3n-6), EPA, PUFA and total FA were higher in ventral skin of fish exposed to enhanced UVB compared with fish in reduced UV treatments. Salmon exposed to reduced UV weighed more per-unit-length than fish exposed to ambient sunlight. The FA profiles suggest that fish exposed to UV radiation were more quiescent than fish in the reduced UV treatments resulting in a buildup of catabolic substrates.     

Isotopic dilution analysis of zinc in some tissue samples of urogenital systems of rats using 65Zn

Zinc plays an important role in prostate functions. For this reason, in this study some rats have been nourished with foods containing different zinc levels and some tissue samples removed at different intervals of time from their prostate, testis, and seminal vesicle. The zinc contents of these samples have been determined using the isotopic dilution analysis technique applied with ⁶⁵Zn. In this way, the zinc contents of tissues varying between 0.02–4.50 μg Zn/g wet tissue could be determined with good precision. As a result, the zinc content of the prostate was found to be considerably high with respect to the zinc contents of the testis and the seminal vesicle. It is also interesting to note that a high zinc level in foods results in the accumulation of zinc in the prostate rather than in the testis and the seminal vesicle. The zinc content of the seminal vesicle decreases with a function of time passed from the beginning of the diet which contrasts with the case of prostate. It is also very remarkable that when the level of zinc in the body is low, the content of zinc in the testis is considerably higher.     

Polycyclic aromatic hydrocarbons (PAHs) in surface sediments of Monastir Bay (Tunisia,Central Mediterranean): distribution,origin and seasonal variations

To assess PAH contamination state of Monastir Bay, surface sediments were collected and analysed for 17 selected parent PAHs by GC/MS. Sediments were sampled from five sites in wet and dry seasons. Total PAH concentrations were in the range of 25.6 to 576.8?ng/g d.wt in winter and 44.9–395.8?ng/g d.wt in summer. Comparison of results with Sediment Quality Guidelines suggested no eco-toxicological risk for benthic organisms. The use of molecular indices has shown that PAHs in surface sediments originate mainly from pyrolytic sources. Total PAH concentrations in surface sediments showed no significant correlations with organic matter content and pelite fraction. The analysis of spatial and seasonal variations of PAHs in surface sediments has demonstrated that final distribution of PAHs in surface sediments is mainly governed by hydrological conditions.     

In vivo and in vitro lipid peroxidation of arachidonate esters: the effect of fish oil omega-3 lipids on product distribution

The effect of lipid composition on the distribution of free radical oxidation products derived from arachidonic acid (20:4) esters has been studied in vitro and in vivo. Pro-inflammatory prostaglandin (PG) F2-like compounds, termed F2-isoprostanes (IsoPs), are produced in vivo and in vitro by the free radical-catalyzed peroxidation of arachidonic acid. Controlled free radical oxidation of mixtures of fatty acid esters in vitro showed that the formation of IsoPs from arachidonate is dramatically influenced by the presence of other fatty acid esters in the reaction mixture. Thus, three lipid mixtures containing the same arachidonate concentration but different amounts of other fatty esters (16:0; 18:1; 18:2; 20:5, and 22:6) were oxidized, and the product yields were determined by GC and LC/MS/MS analysis. The yield of F2-IsoP formed after 1 h of oxidation was 18% (based on arachidonate consumed) for mixtures containing arachidonate as the only oxidizable PUFA, but yields of these biologically active compounds dropped to 6% in polyunsaturated fatty acid (PUFA) mixtures typical of those found in tissues of fish oil-fed animals. F2-IsoP levels were also monitored in the livers of mice on diets supplemented with eicosapentaenoic acid (C20:5 omega-3; EPA), the PUFA most abundant in fish oil. While the level of arachidonic acid present in livers was not significantly different from that in control animals, levels of IsoPs in the liver were reduced in the EPA-fed mice compared to those in controls under conditions of oxidative stress (60 +/- 25% reduction, n = 5) or at baseline (48 +/- 14% reduction, n = 5). These results suggest that dietary omega-3 PUFAs may influence the formation of bio-active peroxidation products derived from omega-6 PUFAs by channeling the free radical pathway away from the F2-IsoPs.