Changes In Total Lipid Content Research Articles

Beneficial Effect of Metformin, Quercetin, and Resveratrol Combination on High Glucose-Induced lipogenesis in HepG2 Cells

Objectives: It has been reported that Metformin (MET), Resveratrol (RSV), and Quercetin (QRS) possess anti-lipogenic effects. This study aimed to investigate the combined effects of these compounds on lipid accumulation in HepG2 cells treated with high glucose (HG).
 Methods: HepG2 cells were treated with HG (33 mM), and different concentrations of MET, QRS, and RSV. The cytotoxic effects of these compounds were determined by an MTT assay. Changes in total lipid content and triglyceride (TG) levels were measured using Oil Red O staining and a triglyceride assay kit, respectively. The expression of fatty acid synthetase (FAS) and sterol regulatory element-binding protein 1c (SREBP1c) was evaluated by quantitative real-time PCR.
 Results: MET at doses 1, 2, and 5 mM, QRS at doses 5, 10, and 20 µM, and RSV at doses 25 and 50 µM could decrease total lipid content and triglyceride levels in HepG2 cells. The EC50 (half maximal effective concentration) from Oil red O staining results were MET: 1.786 mM, QRS: 8.132 μM, and RSV: 10.9 μM. The combination of MET (mM), QRS (µM), and RSV (µM) at ratios of (2:20:50), (1:10:25), and (0.5:5:10), could reduce lipogenesis greater than that observed with each of the individual compounds of MET, QRS, or RSV or the double combinations of MET+QRS or MET+RSV. In addition, combined treatment of MET (0.5mM), QRS (5 µM), and RSV (10 µM) was able to decrease SREBP-1c and FAS genes expression in HG-treated cells.
 Conclusion: The combination of MET, QRS, and RSV could inhibit lipid accumulation in HepG2 cells by reducing total lipid content, triglyceride levels, and the expression of the genes involved in lipogenesis.

Characterization of miR-335-5p and miR-335-3p in human osteoarthritic tissues

ObjectiveWe aimed to characterize the expression patterns, gene targets, and functional effects of miR-335-5p and miR-335-3p among seven primary human knee and hip osteoarthritic tissue types.MethodsWe collected synovial fluid, subchondral bone, articular cartilage, synovium, meniscus/labrum, infrapatellar/acetabular fat, anterior cruciate ligament/ligamentum teres, and vastus medialis oblique/quadratus femoris muscle (n = 7–20) from surgical patients with early- or late-stage osteoarthritis (OA) and quantified miR-335-5p and miR-335-3p expression by real-time PCR. Predicted gene targets were measured in knee OA infrapatellar fat following miRNA inhibitor transfection (n = 3), and prioritized gene targets were validated following miRNA inhibitor and mimic transfection (n = 6). Following pathway analyses, we performed Oil-Red-O staining to assess changes in total lipid content in infrapatellar fat.ResultsShowing a 227-fold increase in knee OA infrapatellar fat (the highest expressing tissue) versus meniscus (the lowest expressing tissue), miR-335-5p was more abundant than miR-335-3p (92-fold increase). MiR-335-5p showed higher expression across knee tissues versus hip tissues, and in late-stage versus early-stage knee OA fat. Exploring candidate genes, VCAM1 and MMP13 were identified as putative direct targets of miR-335-5p and miR-335-3p, respectively, showing downregulation with miRNA mimic transfection. Exploring candidate pathways, predicted miR-335-5p gene targets were enriched in a canonical adipogenesis network (p = 2.1e − 5). Modulation of miR-335-5p in late-stage knee OA fat showed an inverse relationship to total lipid content.ConclusionOur data suggest both miR-335-5p and miR-335-3p regulate gene targets in late-stage knee OA infrapatellar fat, though miR-335-5p appears to be more prominent, with tissue-, joint-, and stage-specific effects.

Two Acyltransferases Contribute Differently to Linolenic Acid Levels in Seed Oil.

Acyltransferases are key contributors to triacylglycerol (TAG) synthesis and, thus, are of great importance for seed oil quality. The effects of increased or decreased expression of ACYL-COENZYME A:DIACYLGLYCEROL ACYLTRANSFERASE1 (DGAT1) or PHOSPHOLIPID:DIACYLGLYCEROL ACYLTRANSFERASE (PDAT) on seed lipid composition were assessed in several Camelina sativa lines. Furthermore, in vitro assays of acyltransferases in microsomal fractions prepared from developing seeds of some of these lines were performed. Decreased expression of DGAT1 led to an increased percentage of 18:3n-3 without any change in total lipid content of the seed. The tri-18:3 TAG increase occurred predominantly in the cotyledon, as determined with matrix-assisted laser desorption/ionization-mass spectrometry, whereas species with two 18:3n-3 acyl groups were elevated in both cotyledon and embryonal axis. PDAT overexpression led to a relative increase of 18:2n-6 at the expense of 18:3n-3, also without affecting the total lipid content. Differential distributions of TAG species also were observed in different parts of the seed. The microsomal assays revealed that C.sativa seeds have very high activity of diacylglycerol-phosphatidylcholine interconversion. The combination of analytical and biochemical data suggests that the higher 18:2n-6 content in the seed oil of the PDAT overexpressors is due to the channeling of fatty acids from phosphatidylcholine into TAG before being desaturated to 18:3n-3, caused by the high activity of PDAT in general and by PDAT specificity for 18:2n-6. The higher levels of 18:3n-3 in DGAT1-silencing lines are likely due to the compensatory activity of a TAG-synthesizing enzyme with specificity for this acyl group and more desaturation of acyl groups occurring on phosphatidylcholine.

Fatty acid profile of cultured green abalone (Haliotis fulgens) exposed to lipid restriction and long-term starvation

The fatty acid composition of juvenile green abalone (Haliotis fulgens) exposed to lipid restriction and long-term starvation was studied. Juvenile organisms were acclimated during 26 days and then randomly separated into three treatment groups. One group was fed a restricted diet containing low lipid content (0.14%), another was fed a rich diet containing the optimal lipid content (5.1%), and the third was kept under starvation conditions. After 90 days, the abalone fed the restricted diet showed a significant increase in 18:1n-9 content and a decrease in n-3 and n-6 polyunsaturated fatty acids (PUFA), but the total lipid level remained similar to that observed before the treatment, suggesting lipogenesis. On the other hand, no changes in total lipid content and fatty acid profile were found during the 90-day treatment using the rich lipid diet compared with the initial samples. Starved abalone showed that lipids did not constitute the main energy source and that the concentrations of long-chain PUFA did not change throughout the 90-day starvation period.

Not only accumulation, but also saturation status of intramuscular lipids is significantly affected by PPARγ activation

Intramuscular lipid accumulation has been associated with insulin resistance, and after thiazolidinediones (TZD) treatment, it was shown to be reduced in some, but not all, studies. This work was undertaken to investigate the relationships between intramuscular lipids [free fatty acids (FFA), diacylglycerols (DAG), triacylglycerol (TAG) and phospholipids] and plasmalemmal expression of fatty acid (FA) transporter [FAT/CD36 and FABPpm] in the muscles of varying oxidative capacity, after peroxisome proliferator-activated receptors gamma (PPARγ) activation (rosiglitazone) in an animal model of high-fat-diet-induced insulin resistance. Endurance training was also included to further explore the differences in these relationships. We have used gas liquid chromatography to estimate FA content and composition in each lipid fraction. For sarcolemmal expression of FA transporters, subfractionation of skeletal muscles with subsequent western blot technique was applied. High-fat diet induced intramuscular accumulation of FFA, DAG and TAG, irrespective of muscle's fibre composition. PPARγ activation (rosiglitazone) and, to a lesser extent, endurance training further increased TAG accumulation, while it reduced DAG in oxidative muscles (soleus and red gastrocnemius). Aforementioned interventions increased also sarcolemmal FAT/CD36 and FABPpm expressions in particular muscles. Irrespective of diet, rosiglitazone and exercise decreased significantly FA saturation status favouring proportionate enhancement in monounsaturated FA (rosiglitazone) or polyunsaturated FAs (endurance training). These findings support the conclusion that not only the change in total lipid content (DAG and TAG), but also FA composition is affected by rosiglitazone in an animal model of high-fat-diet-induced insulin resistance.

Changes in total lipid contents of marine diatom Nitzschia frustulum at various temperatures under Si deficiency

The photosynthetic marine diatom Nitzschia frustulum was grown autotrophically in a photobioreactor in two stages. In the first stage, cells were grown for 7 days to Si deficiency at the optimally adapted temperature of 22 °C. In the second stage, they were grown for 2 more days at a new temperature ranging from 12 °C to 37 °C; then the contents of total lipids in the harvested diatom samples were measured. The total lipid content of the final diatom cells grown at the altered temperatures between 17 and 32 °C changed little from 15.1% (wt) of the dried cells harvested before the temperature changes. However, it increased to 21% (wt) for cells grown at a low temperature of 12 °C and decreased drastically to 7% (wt) at a high temperature of 37 °C.

Effect of different cooking methods on lipid oxidation and formation of free cholesterol oxidation products (COPs) in Latissimus dorsi muscle of Iberian pigs

The aim of this work was to study the influence of different cooking methods (grilled (GR), fried (FP), microwave (MW) and roasted (RO)) on lipid oxidation and formation of free cholesterol oxidation products (COPs) of meat from Iberian pigs that have been fed on an intensive system. Moisture and total lipid content, TBARs, hexanal and COPs were measured in Latissimus dorsi muscle samples. Cooking did not produce changes in total lipid content in meat but induced significantly higher lipid oxidation (TBARs and hexanal values) ( p < 0.001) and cholesterol oxidation (COPs) ( p < 0.01). When the different cooking methods were studied, the grilled method was the least affected by lipid oxidation (TBARs and hexanal) compared to the others. There were no significant differences among different cooking methods on COPs values. The most abundant cholesterol oxides were both 7α-hydroxycholesterol and 7β-hydroxycholesterol in all groups studied.

Changes in fatty acid composition in muscle and adipose tissue of farmed rainbow trout (Oncorhynchus mykiss) in relation to ration and age

To evaluate the importance of age and feed ration level (RL) on the composition of tissue fatty acid (FA) in rainbow trout (Oncorhynchus mykiss), fish were fed rations ranging from appreciable underfeeding to gross overfeeding in a longitudinal experiment lasting from start of feeding to onset of sexual maturation 2.4 years later. In order to study the effects of compensatory growth and reduced feed availability, fish were moved from high to low ration and vice versa. Changes of individual FA of total lipid (TL), triacylglycerols (TAG) and total phospholipids (PL) were studied in white and red muscle, as well as in three major adipose tissues. The effect of saltwater transfer on FA composition was also examined. A strong interdependence was found between the relative proportion of PL and TAG with changes in TL content. This was most prominent in white muscle. In parallel with this change in relative lipid class composition, a major effect was seen on FA in the TL fraction. The most marked effect of RL was an inverse relationship between 22:6 n-3 of the PUFA n-3 series and 16:1 and 18:1 of the MUFA series. This was seen in all tissues studied. It is suggested that the most important factor governing FA composition in muscle, pending changes in feed intake, is the TL content, affecting the relative level of PL and TAG. In adipose tissue, consisting mainly of TAG, more subtle changes were observed. The FA compositions of PL and TAG were not affected to any major extent by RL, except at extreme reductions. Significant changes in FA of PL and TAG were observed as an effect of saltwater transfer.

Changes Associated with Post-harvest Ageing in Almond Seeds

Four different varieties of almond seeds (Prunus dulcis (Mill.) D. A. Webb, syn. P. amygdalus Batsch, and P. communis (L.)) aged over two years in the dark at room temperature were analysed for changes in total lipid content, fatty acid profiles, soluble protein concentration, lipoxygenase activity, malondialdehyde and hydroperoxide production, and α -tocopherol content. Twenty-four months storage resulted in degradative changes in almond taste. Ageing induced accumulation of hydroperoxides and malondialdehyde, suggesting that seed deterioration was associated with lipid peroxidation. In aged seeds the lipid content dropped; the levels of linoleic and α -linolenic acids in total and polar lipid fraction also decreased. Lipoxygenase activity and protein content remained more or less unchanged; conversely antioxidant α -tocopherol which was constitutively at high concentration (25–84 mg/100 g of dry weight (d.w.)) in all four varieties showed a marked decline after ageing. A possible relationship between α -tocopherol and lipid peroxidation is discussed.

Lipid content of stream macroinvertebrates

Total lipid content of freshwater macroinvertebrates from different orders and with different life histories was investigated. Lipids were determined as HIP-extractable lipids (HIP = hexane: isopropanol). Macroinvertebrate taxa were assigned to different feeding guilds, and life histories for insect taxa: Gammarus pulex (Amphipoda/shredder), Ecdyonurus sp. (Ephemeroptera/hemimetabolous/grazer), Perla sp. (Plecoptera/hemimetabolous/predator), Hydrophsyche sp. (Trichoptera/holometabolous/ suspension feeder), and Atherix ibis (Diptera/holometabolous/predator). Animals were collected in two streams in Switzerland bimonthly between October 1994 and October 1995. Lipids, expressed as percent dry mass (dm), were estimated using two techniques: (1) as total lipid content, determined by the sulphophosphovanilline method; (2) as total fatty acids (= sum of fatty acids), determined by gas chromatography. The annual average total lipid contents for G. pulex, Ecdyonurus and Perla were 6.1 %, 7.0 % and 6.0 % dm, respectively. The two holometabolous insects, Hydropsyche (8.0 %) and A. ibis (9.3 %), exhibited the highest total lipid content. Total fatty acids as a percentage of total lipids was lowest in G. pulex (62 %), followed by Ecdyonurus (64 %), Perla (73 %), Hydropsyche (80 %), and A. ibis (85 %), The dry mass of holometabolous insects (Hydropsyche and A. ibis) related positively with lipids, indicating an increase in body concentration during larval growth. No or only a weak positive relationship with dry mass was found for the hemimetabolous Ecdyonurus and Perla. Gammarus pulex, in contrast, showed a negative relationship. Male G. pulex attained a larger size and contained less fat than juveniles and adult females. Seasonal changes in total lipid content were recognisable only as weak trends because of high variation among individuals. Gammarus pulex had higher total lipid content in spring, while Perla and Hydropsyche maxima occurred in summer. No seasonal trends in total lipid content could be observed in Ecdyonurus and A. ibis.

Differences in the total lipid and lipid class composition of larvae and metamorphosing sea lampreys, Petromyzon marinus

This study compared the alterations in total lipid and lipid class composition of kidney, liver, and intestine from sea lamprey, Petromyzon marinus, during their nontrophic metamorphosis with these parameters in unmetamorphosed larvae. Total lipid in kidney and liver initially was higher by 104 and 66%, respectively, in the earliest metamorphic stage (3) examined compared to larvae and then decreased by 73 and 37%, respectively, from stage 3 to stage 7. Total lipid in intestine, on the other hand, was 53% lower at stage 3 compared to larvae and then significantly increased by 260% from stage 3 to stage 7. Large amounts of triacylglycerol (TG) in kidney and liver implicate these organs as lipid depots; much of the change in total lipid content of kidney and liver could be explained by alterations in TG, although significant variations in other lipid classes (e.g., phospholipid, cholesterol) also were noted. These results suggest that lamprey metamorphosis may proceed in two metabolic phases in a tissue-specific manner and that lipid depletion results from specific catabolism of stored TG reserves.

Dieldrin Pretreatment Alters [14C]Dieldrin and [3H]7,12-Dimethylbenz[a]anthracene Uptake in Rainbow Trout Liver Slices

We previously demonstrated that pretreatment of rainbow trout with the organochlorine insecticide dieldrin alteredin vivodisposition of a subsequent [14C]dieldrin dose. This was not explained by changes in total lipid content or the activity of common xenobiotic metabolizing enzymes. We hypothesized that dieldrin induced hepatic proteins responsible for organochlorine (OC) sequestration, transport, or excretion and that these changes reflected an adaptive response of trout to OC exposure. Here, uptake of 1.18 μM[14C]dieldrin by precision cut liver slices was increased by dieldrin pretreatment of rainbow trout. Uptake of 0.118 and 1.18 μM[3H]7,12-dimethylbenz[a]anthracene (DMBA) and efflux of 0.118 μM[3H]DMBA were significantly increased in slices from dieldrin-pretreated trout. Liver slice uptake of 10 but not 1.18 μM[3H]estradiol and [3H]cholic acid was significantly increased by dieldrin pretreatment. There were no such significant differences for [3H]cholesterol, [3H]cholesterol-oleate, or [3H]oleic acid uptake. Dieldrin pretreatment did not alter hepatic microsomal metabolism of [3H]DMBA or [14C]benzo[a]pyrene or content of six cytochrome P450 isozymes, as quantitated by Western blot analysis. These results provide further evidence that altered disposition of [14C]dieldrin and [3H]DMBA in dieldrin-pretreated trout was not explained by microsomal enzyme induction but reflected altered processes integral to hepatocellular transmembrane kinetics. These changes may have important implications for OC bioaccumulation by rainbow trout and demonstrate an interaction between dieldrin and DMBA in the absence of cytochrome P450 system induction.

Loss of lymphocyte modulatory control by surfactant lipid extracts from acute hypersensitivity pneumonitis: comparison with sarcoidosis and idiopathic pulmonary fibrosis

Surfactant components are recognized to exert a regulatory control on lymphocytes in physiological conditions, as testified by in vitro studies. However, what happens following lung injury has not been established. As surfactant composition is altered in interstitial lung diseases, this work was carried out to compare the modulatory impact of normal human alveolar fluids on lymphocyte proliferation, with that from inflammatory lung diseases which are characterized by distinct patterns of immunologically-mediated alterations (i.e. sarcoidosis, acute hypersensitivity pneumonitis, idiopathic pulmonary fibrosis). Thymidine incorporation of allogeneic normal human blood lymphocytes was studied in the presence of total alveolar fluids or lipid extracts from 37 subjects, and phytohaemagglutinin (PHA) as T-cell mitogen. The results show that: 1) total alveolar fluids and lipid extracts from normal subjects share a concentration-dependent suppressive activity on T-cell proliferation; 2) total alveolar fluids from diseased patients have lost this property, either by a lack of suppressive activity (i.e. idiopathic pulmonary fibrosis) or even by enhanced activity (i.e. sarcoidosis and hypersensitivity pneumonitis); 3) lipid extracts from diseased patients still retain the suppressive activity of normal subjects, except for hypersensitivity; and 4) an imbalance in surfactant phospholipids with an increase in the inducers to suppressors ratio is more likely to explain this alteration in hypersensitivity pnuemonitis than changes in total lipid content. In conclusion, alveolar lipid extracts from acute hypersensitivity pnuemonitis have lost the modulatory control normally exerted by surfactant lipids on lymphocyte proliferation in vitro. This alteration may contribute to the invasion of the lung by lymphocytes in acute hypersensitivity pnuemonitis in vivo.

A comparison of highly unsaturated fatty acid levels in wild and farmed eels ( Anguilla Anguilla)

1. 1. Absolute and relative amounts of eicosapentaenoic acid (EPA) and docohexaenoic acid (DHA) in muscle of eels from four different fish farms were compared with samples from wild eels from two different areas of northern Italy. 2. 2. Farmed eels were richer in DHA and EPA than wild animals. 3. 3. The addition of cod liver oil to the diet of farmed eels led to a significant accumulation of EPA and DHA, but no change in total lipid content. 4. 4. The calculation of two indices related to highly unsaturated fatty acid (HUFA) content (FLQ = fish lipid quality; Al = aterogenic index), indicated the higher nutritional value of farmed vs wild fish. 5. 5. We conclude that farmed eels are an adequate source of fish products for human nutrition and propose use of the above-mentioned indices as an effective means for assessing fish nutritional quality for populations at high risk of chronic degenerative disease.

Variation in Lipid and Fatty Acid Contents of Atlantic Croakers, Striped Mullet, and Summer Flounder

Lipid and fatty acid contents of fillets (with skin) of Atlantic croakers Micropogonias undulatus, striped mullet Mugil cephalus, and summer flounder Paralichthys dentatus were determined for three harvest dates over a 1-year period. In striped mullet and Atlantic croakers, total lipid increased significantly (P ≤ 0.05) in late summer (from 21.72 to 31.78% and 12.68 to 31.94% of dry weight, respectively). No significant change in total lipid content was noted in the leaner summer flounder (9.38–9.87%). However, polyunsaturated fatty acid (PUFA) content of fillets of summer flounder varied significantly (P ≤ 0.05), ranging from low levels in June and August (6.24 and 3.33% of dry weight, respectively) to much higher levels (17.32%) in January. The difference in PUFA content of fillets was due mainly to a significant increase in docosahexaenoic acid (22: 6n3). The PUFA content of Atlantic croakers (22:6n3) also increased significantly (from 3.19 to 6.16%) from August to January, but the PUFA content of striped mullet did not change significantly. These results indicate that generalizations cannot easily be made concerning the lipid and fatty acid composition offish. We speculate that for some species (e.g., Atlantic croaker and striped mullet), high food availability linked with preparation for spawning is a primary determinant of lipid content, but for other fish (e.g., summer flounder), changes of PUFA content in response to temperature change are more important.

Low Temperature Development Induces a Specific Decrease in trans-Δ3-Hexadecenoic Acid Content which Influences LHCII Organization

Lipid and fatty acid analyses were performed on whole leaf extracts and isolated thylakoids from winter rye (Secale cereale L. cv Puma) grown at 5 degrees C cold-hardened rye (RH) and 20 degrees C nonhardened rye (RNH). Although no significant change in total lipid content was observed, growth at low, cold-hardening temperature resulted in a specific 67% (thylakoids) to 74% (whole leaves) decrease in the trans-Delta(3)-hexadecenoic acid (trans-16:1) level associated with phosphatidyldiacylglycerol (PG). Electron spin resonance and differential scanning calorimetry (DSC) indicated no significant difference in the fluidity of RH and RNH thylakoids. Separation of chlorophyll-protein complexes by sodium dodecyl sulfate-polyacrylamide gel electrophoresis indicated that the ratio of oligomeric light harvesting complex:monomeric light harvesting complex (LHCII(1):LHCII(3)) was 2-fold higher in RNH than RH thylakoids. The ratio of CP1a:CP1 was also 1.5-fold higher in RNH than RH thylakoids. Analyses of winter rye grown at 20, 15, 10, and 5 degrees C indicated that both, the trans-16:1 acid levels in PG and the LHCII(1):LHCII(3) decreased concomitantly with a decrease in growth temperature. Above 40 degrees C, differential scanning calorimetry of RNH thylakoids indicated the presence of five major endotherms (47, 60, 67, 73, and 86 degrees C). Although the general features of the temperature transitions observed above 40 degrees C in RH thylakoids were similar to those observed for RNH thylakoids, the transitions at 60 and 73 degrees C were resolved as inflections only and RH thylakoids exhibited transitions at 45 and 84 degrees C which were 2 degrees C lower than those observed in RNH thylakoids. Since polypeptide and lipid compositions of RH and RNH thylakoids were very similar, we suggest that these differences reflect alterations in thylakoid membrane organization. Specifically, it is suggested that low developmental temperature modulates LHCII organization such that oligomeric LHCII predominates in RNH thylakoids whereas a monomeric or an intermediate form of LHCII predominates in RH thylakoids. Furthermore, we conclude that low developmental temperature modulates LHCII organization by specifically altering the fatty composition of thylakoid PG.

Effect of Storage on Lipid Composition and Functional Properties of Dried Egg Products ,

Changes in functional properties and lipid composition of whole egg solids, egg yolk solids, and free flowing egg yolk solids stored at 1.7, 12.8, 23.9 and 35 C for 3 to 6 months were examined. In general, storage of dried egg products at 23.9 C for 6 months or at 35 C for 3 months or more resulted in a decrease of pH, emulsion stability (mayonnaise test), and cephalin content. Viscosity of rehydrated egg products increased markedly at higher storage temperatures. Browning of egg products, as measured by Gardner values, was observed under high storage temperatures. No changes in total lipid content, lecithin content, and fatty acid composition were observed in this study.

Total, polar and neutral lipids of Rhizopus arrhizus Fischer.

AbstractThe changes in total lipid content, neutral and polar lipids, total fatty acids, and free fatty acids were investigated over a 4 day period in the zygomycete,Rhizopus arrhizus Fischer. The highest concentration of lipids occurred at the 72 hr period. The degree of unsaturation in the total fatty acid fraction increased during the growth period, whereas the degree of unsaturation decreased in the free fatty acid fraction during the same time period. The ratios of neutral to polar lipids over the 4 day period were: 0.75, 0.22, 1.94 and 0.94. The major components of polar lipids were phosphatidyl ethanolamine, lecithin, lysolecithin, and fatty acids. The fatty acids in the mono‐ and diglycerides were predominately saturated (67–96%). The fatty acids in the triglycerides shifted from a predominately unaturated (69%, 24 hr) to a more saturated pattern (62%, 96 hr).

Lipid content and seasonal activity of Odontopus calceatus (Coleoptera: Curculionidae) adults.

Overwintering Odontopus calceatus (Say) adults were first observed feeding on April 10. Weekly collections during the activity period indicated that new-generation adults began emerging June 4. By July 23 they had entered the forest litter for hibernation. Lipid content decreased throughout the hibernation period as the weevils utilized 77% of their total lipid content during The time. The most rapid decrease during hibernation occurred February to March, just prior to mating and oviposition in the spring. No increase in lipid content occurred during me activity period in spring and summer. A great increase in lipid content did occur within a month after the weevils had entered the litter for hibernation. Only quantitative changes in total lipid content were determined.

EFFECTS OF DIETARY PHOSPHOLIPID AND CHOLESTEROL ON THE TEMPERATURE RESISTANCE OF GOLDFISH

The temperature resistance of goldfish is increased by additions of cholesterol or phospholipid to basic diets of pablum or pablum and pilchard oil. The relative effectiveness of these treatments varies with the season and with the duration of the feeding experiment. In low-temperature resistance tests, the cholesterol effect was most marked during the earlier period of chilling and the suggestion is that cholesterol increases the capacity of fish to resist cold narcosis—not death. In heat, resistance tests, the phospholipid-fed fish showed a tendency toward heat narcosis which was not evident with cholesterol-fed animals. Increased temperature resistance was closely correlated with increased tissue cholesterol but only weakly correlated with the less modified tissue phospholipid. Although these diets also produced definite changes in total lipid content, moisture content, unsaturation of total lipids, and the cholesterol/phospholipid ratio, no evident correlation between these factors and temperature resistance of the goldfish was found. Data are discussed in relation to several theories of temperature death.