bluuebunny/crossref_metadata_2025_split huggingface dataset:
Body size and resource partitioning in ladybirds
Authors: Dixon A. F. G. 
Published: November 2006

AbstractAphidophagous insects all exploit aphids as food, but there appears to be no association between the size of the aphidophagous predator and that of the species or the age structure of the aphid colonies they exploit. Aphid colonies generally increase, peak and decline in abundance, and are exploited by a sequence of predators, which is consistent from year to year. The objective of this study was to determine the rules underlying this temporal pattern. For example, in the field, aphid colonies are often first attacked by a small and then a larger species of ladybird. Theory based on the geometry and physiology of ladybirds predicts that the quantity of food required for oviposition and the area searched per unit time should scale with body weight, with exponents of 1 and 0.66, respectively. An analysis of empirical data supports these predictions. Thus, in relative terms a 35 mg ladybird requires 1.5 times more aphids per unit area for oviposition than a 10 mg ladybird. That is, the temporal pattern in oviposition is possibly mainly determined by geometrical and physiological constraints associated with body size, with small species of ladybird able to lay eggs at lower aphid population densities than large species. Cannibalism is thought to be the mechanism by which these predators are able to coexist.
Effects of dietary lipids on daunomycin‐induced nephropathy in mice: Comparison between cod liver oil and soybean oil
Authors: Ohtake Takayasu , Kimura Masato , Takemura Hitomi , Hishida Akira 
Published: November 2006

AbstractAlthough it is well known that dietary lipids affect the course of glomerulonephritis in rats and humans, the precise mechanisms involved have not been fully elucidated. The aim of this study was to investigate the effects of different types of dietary lipids (fish oil and vegetable oil) on daunomycin (DM)‐induced nephropathy in mice fed on soybean oil (SO) or cod liver oil (CLO). Urinary protein excretion, serum albumin, creatinine, total cholesterol, and TG were measured, and glomerular histological changes were evaluated. Antioxidant enzymes were also measured, along with the levels of lipid peroxide, GSH, thromboxane (Tx) B2′ and 6‐keto prostaglandin F1α in renal cortical tissue. Dietary CLO significantly reduced urinary albumin excretion and ameliorated the histological changes induced by DM. The increase of tissue lipid peroxide levels seen in SO‐fed mice was suppressed in CLO‐fed mice, whereas CLO‐fed mice showed higher GSH levels than SO‐fed mice throughout the experiment. In addition, renal tissue GSH peroxidase activity was significantly higher at 72 h after DM injection in CLO‐DM mice than in SO‐DM mice. Both renal cortical TxB2 and 6‐keto PGF1α levels were significantly lower in CLO‐DM mice than in SO‐DM mice. These results suggest that inhibition of oxidative damage by dietary CLO played an important role in the prevention of DM nephropathy in this mouse model. The effect of CLO was closely associated with the inhibition of Tx synthesis.
Long‐term n‐3 FA deficiency modifies peroxisome proliferator‐activated receptor β mRNA abundance in rat ocular tissues
Authors: Rojas Cecilia V. , Greiner Rebecca S. , Fuenzalida Lidia C. , Martínez Jessica I. , Salem Norman , Uauy Ricardo 
Published: November 2006

AbstractPeroxisomal proliferator‐activated receptors (PPAR) are a FA‐response system involved in diverse cellular responses. FA regulate PPAR activity and modulate PPAR mRNA abundance. Increasing evidence indicates that PUFA are required for optimal neuronal development and function. To gain insight into the mechanism for nutrition‐induced impairment of neuronal development and function we investigated the effect of chronic n‐3 FA deficiency on PPAR mRNA levels in rat brain and ocular tissues. Rats were fed for three generations a diet designed to reduce DHA levels in tissues, and the abundance of PPARα and PPARβ transcripts was measured by hybridization with specific probes. Chronic consumption of the α‐linolenic acid (LNA)‐insufficient diet caused a remarkable modification in DHA content in membrane phospholipids. The results reported here indicate that PPARα mRNA levels did not exhibit significant variation in ocular, hepatic, or nervous tissues from rats fed the experimental diet. In contrast, PPARβ mRNA normalized to β‐actin mRNA was 21% higher in ocular tissue from F3 generation rats consuming the LNA‐deficient diet but was independent of diet in hepatic and nervous tissues. The absolute abundance of PPARβ transcripts showed a 17% increase in ocular tissue from rats consuming the LNA‐deficient diet (F3 generation). The biological significance of the reported changes in PPARβ mRNA in ocular tissue remains to be determined.
Dietary cholesterol modulates Δ6 and Δ9 desaturase mRNAs and enzymatic activity in rats fed a low‐EFA diet
Authors: Brenner Rodolfo R. , Bernasconi Ana M. , González María S. , Rimoldi Omar J. 
Published: November 2006

AbstractThe effects of a 1% addition of cholesterol to a diet low in EFA on FA desaturases were examined. The administration of cholesterol markedly increased the esterified cholesterol content in microsomes and total liver lipids from the first day, whereas the proportion of free cholesterol remained unaltered throughout the treatment. An excellent homeostasis in the free cholesterol content was apparently evoked by the acyl‐CoA cholesterol acyltransferase. The cholesterol esters were mainly oleate, palmitate, and stearate, and the addition of cholesterol increased the relative proportions of cholesterol palmitoleate and oleate. The addition of cholesterol to a low‐EFA diet induced, as in animals fed a high‐FFA diet, a marked increase in liver stearoyl‐CoA desaturase‐1 mRNA and enzyme activity. This increased activity apparently evoked a similar enhancement of palmitoleic and oleic acids in total and microsomal liver lipids. The cholesterol‐rich diet depressed the liver Δ6 and Δ5 desaturase activity. However, the abundance of Δ6 desaturase mRNA was not modified throughout the treatment. This indicates that the depressive effect is evoked at a step beyond that controlled by the mRNA level. The depression of both enzymatic activities was consistent with the decrease in the percentages of arachidonic acid and DHA in total and microsomal liver lipids. Taken together, these results indicate that through its modulating effect on the desaturases, dietary cholesterol may lead an animal or humaan fed low‐EFA diet to a true deficiency by the decreased synthesis of the highly polyunsaturated acids derived from linoleic and α‐linolenic acids.
Increased cardiomyocyte apoptosis following ischemia and reperfusion in diet‐induced hypercholesterolemia: Relation to Bcl‐2 and bax proteins and caspase‐3 activity
Authors: Wang Tzung‐Dau , Chen Wen‐Jone , Su Sophia Seh‐Yi , Lo Shyh‐Chyi , Lin Wan‐Wan , Lee Yuan‐Teh 
Published: November 2006

AbstractIt has been reported that apoptosis is a significant contributor to myocardial cell death as a result of reperfusion injury. However, whether the extent of cardiomyocyte apoptosis following ischemia and reperfusion varies in different pathophysiological backgrounds is still uncertain. In this study, we examined whether hypercholesterolemia increases the extent of myocardial reperfusion injury by aggravating cardiomyocyte apoptosis and the effects of hypercholesterolemia on the expression of Bcl‐2 and Bax proteins and the activation of caspase‐3. Twenty‐eight male New Zealand white rabbits were fed standard chow (control, n=14) or chow supplemented with 1% cholesterol (hypercholesterolemic, n=14) for 8 wk. Anesthetized rabbits were then subjected to 30 min of left circumflex artery occlusion followed by 4 h of reperfusion. Apoptosis was identified as “DNA ladders” by gel electrophoresis and confirmed histologically using the terminal deoxynucleotidyl transferase‐mediated dUTP‐biotin nick end labeling (TUNEL) assay. The infarct size (% of risk region) was significantly greater in hypercholesterolemic rabbits than in controls (39±6 vs. 23±2%, P=0.02). Very few TUNEL‐positive cardiomyocytes could be identified in the nonischemic regions in both groups, consistent with an absence of DNA laddering. In contrast, TUNEL‐positive cardiomyocytes were significantly displayed in the ischemic, nonnecrotic myocardium, and DNA ladder occurred in all animals. The percentage of TUNEL‐positive cardiomyocytes in the ischemic nonnecrotic myocardium was significantly higher in hypercholesterolemic rabbits compared with controls (40±5 vs. 17±1%, P<0.001). Western blot analysis showed that, in the nonischemic myocardium, hypercholesterolemic rabbits exhibited an approximately 50% increase in the expression of Bcl‐2 (P<0.05), but not Bax, than control rabbit. However, compared with controls, hypercholesterolemic rabbits exhibited a more pronounced decrease in the expression of Bcl‐2 (42±4 vs. 26±2%, P<0.01) and a similar extent of increase in the expression of Bax in the ischemic myocardium. Furthermore, hypercholesterolemic rabbits were associated with a markedly increased activation of caspase‐3 within the ischemic myocardium compared to control rabbits. This study demonstrates that although hypercholesterolemia is associated with an increased myocardial Bcl‐2/Bax ratio at baseline, it still significantly exacerbates cardiac reperfusion injury, not only by increasing the infarct size but also by increasing the extent of cardiomyocyte apoptosis.
Effect of SMP‐500, a novel ACAT inhibitor, on hepatic cholesterol disposition in rats
Authors: Ioriya Katsuhisa , Nishimura Takeshi , Ohashi Naohito 
Published: November 2006

AbstractThe effects of SMP‐500, a novel ACAT inhibitor, on serum lipid levels, hepatic lipid secretion rate, and hepatic lipid disposition in rats were studied to clarify its lipid‐lowering action. SMP‐500 reduced the serum cholesterol level in a dose‐dependent manner in rats fed a hypercholesterolemic diet. SMP‐500 also reduced hepatic free cholesterol content in addition to hepatic total and esterified cholesterol contents. Biliary concentrations of cholesterol and bile acid were increased by SMP‐500; however, the bile flow and lithogenic index were not affected. SMP‐500 increased cholesterol 7α‐hydroxylase mRNA level. Therefore, it is suggested that the increase in concentrations of cholesterol and bile acid in bile is due to both the increase of bile acid production through the increase of cholesterol 7α‐hydroxylase and the decrease of hepatic free cholesterol content. An inhibitory effect of SMP‐500 both on the cholesterol secretion and on the TG secretion from liver was observed. SMP‐500 reduced the serum TG level in sucrose‐fed rats. From these results, one may hypothesize that the suppression of hepatic VLDL secretion probably plays an important role on both cholesterol‐ and TG‐lowering effects of SMP‐500.
FA composition of heart and skeletal muscle during embryonic development of the king penguin
Authors: Decrock Frederic , Groscolas René , Speake Brian K. 
Published: November 2006

AbstractSince the yolk lipids of the king penguin (Aptenodytes patagonicus) naturally contain the highest concentrations of DHA and FPA yet reported for the eggs of any avian species, the effects of this (n‐3)‐rich yolk on the FA profiles of the embryonic heart and skeletal muscle were investigated. The concentrations (mg/g wet tissue) of phospholipid (PL) in the developing heart and leg muscle of the penguin doubled between days 27 and 55 from the beginning of egg incubation (i.e., from the halfway stage of embryonic development of 2 d posthatch), whereas no net increase occurred in pectoral muscle. During this period, the concentration of TAG in heart decreased by half but increased two‐ and sixfold in leg and pectoral muscle, respectively. The most notable change in cholesteryl ester concentration occurred in pectoral muscle, increasing ninefold between days 27 and 55. Arachidonic acid (ARA) was the major polyunsaturate in PL of the penguin's heart, where it formed about 20% (w/w) of FA at day 55. At the equivalent developmental stage, the heart PL of the chicken contained a 1.3‐fold greater proportion of ARA, contained a fifth less DHA, and was almost devoid of EPA, whereas the latter FA was a significant component (7% of FA) of penguin heart PL. Similarly, in PL of leg and pectoral muscle, the chicken displayed about 1.4‐fold more ARA, up to 50% less DHA, and far less EPA in comparison with the penguin. Thus, although ARA‐rich PL profiles are achieved in the heart and muscle of the penguin embryo, these profiles are significantly affected by the high n‐3 content of the yolk.
Biosynthesis of new divinyl ether oxylipins in Ranunculus plants
Authors: Hamberg Mats 
Published: November 2006

Abstract[1‐14C]Linolenic acid was incubated with homogenates of leaves from the aquatic plants Ranunculus lingua (greater spearwort) or R. peltatus (pond water‐crowfoot). Analysis by reversed‐phase high‐performance liquid radiochromatography demonstrated the formation of a new divinyl ether FA, i.e., 12‐[1′(E), 3′(Z)‐hexadienyloxy]‐9(Z), 11(Z)‐dodecadienoic acid [11(Z)‐etherolenic acid] as well as a smaller proportion of ω5(Z)‐etherolenic acid previously identified in terrestrial Ranunculus plants. The same divinyl ethers were formed upon incubation of 13(S)‐hydroperoxy‐9(Z), 11(E), 15(Z)‐octadecatrienoic acid, a lipoxygenase metabolite of linolenic acid, whereas the isomeric hydroperoxide, 9(S)‐hydroperoxy‐10(E), 12(Z), 15(Z)‐octadecatrienoic acid, was not converted into divinyl ethers in R. lingua or R. peltatus. Incubation of [1‐14C]linoleic acid or 13(S)‐hydroperoxy‐9(Z), 11(E)‐octadecadienoic acid produced the divinyl ether 12‐[1′(E)‐hexenyloxy]‐9(Z), 11(Z)‐dodecadienoic acid [11(Z)‐etheroleic acid] and a smaller amount of ω5(Z)‐etheroleic acid. The experiments demonstrated the existence in R. lingua and R. peltatus of a divinyl ether synthase distinct from those previously encountered in higher plants and algae.
General characteristics of Pinus spp. Seed fatty acid compositions, and importance of Δ5‐olefinic acids in the taxonomy and phylogeny of the genus
Authors: Wolff Robert L. , Pédrono Frédérique , Pasquier Elodie , Marpeau Anne M. 
Published: November 2006

AbstractThe Δ5‐unsaturated polymethylene‐interrupted fatty acid (Δ5‐UPIFA) contents and profiles of gymnosperm seeds are useful chemometric data for the taxonomy and phylogeny of that division, and these acids may also have some biomedical or nutritional applications. We recapitulate here all data available on pine (Pinus; the largest genus in the family Pinaceae) seed fatty acid (SFA) compositions, including 28 unpublished compositions. This overview encompasses 76 species, subspecies, and varieties, which is approximately one‐half of all extant pines officially recognized at these taxon levels. Qualitatively, the SFA from all pine species analyzed so far are identical. The genus Pinus is coherently united—but this qualitative feature can be extended to the whole family Pinaceae—by the presence of Δ5‐UPIFA with C18 [taxoleic (5,9–18∶2) and pinolenic (5,9,12–18∶3) acids] and C20 chains [5,11–20∶2, and sciadonic (5,11,14–20∶3) acids]. Not a single pine species was found so far with any of these acids missing. Linoleic acid is almost always, except in a few cases, the prominent SFA, in the range 40–60% of total fatty acids. The second habitual SFA is oleic acid, from 12 to 30%. Exceptions, however, occur, particularly in the Cembroides subsection, where oleic acid reaches ca. 45%, a value higher than that of linoleic acid. α‐Linolenic acid, on the other hand, is a minor constituent of pine SFA, almost always less than 1%, but that would reach 2.7% in one species (P. merkusii). The sum of saturated acids [16∶0 (major) and 18∶0 (minor) acids principally] is most often less than 10% of total SFA, and anteiso‐17∶0 acid is present in all species in amounts up to 0.3%. Regarding C18 Δ5‐UPIFA, taxoleic acid reaches a maximum of 4.5% of total SFA, whereas pinolenic acid varies from 0.1 to 25.3%. The very minor coniferonic (5,9,12,15–18∶4) acid is less than 0.2% in all species. The C20 elongation product of pinolenic acid, bishomo‐pinolenic (7,11,14–20∶3) acid, is a frequent though minor SFA constituent (maximum, 0.7%). When considering C20 Δ5‐UPIFA, a difference is noted between the subgenera Strobus and Pinus. In the former subgenus, 5,11–20∶2 and sciadonic acids are ≤0.3 and ≤1.9%, respectively, whereas in the latter subgenus, they are most often ≥0.3 and ≥2.0%, respectively. The highest values for 5,11–20∶2 and sciadonic acids are 0.5% (many species) and 7.0% (P. pinaster). The 5,11,14,17–20∶4 (juniperonic) acid is present occasionally in trace amounts. The highest level of total Δ5‐UPIFA is 30–31% (P. sylvestris), and the lowest level is 0.6% (P. monophylla). Uniting as well as discriminating features that may complement the knowledge about the taxonomy and phylogeny of pines are emphasized.
The biosynthesis of oxylipins of linoleic and arachidonic acids by the sewage fungus Leptomitus lacteus, including the identification of 8R‐hydroxy‐9Z,12Z‐octadecadienoic acid
Authors: Fox Simon R. , Akpinar Arzu , Prabhune Asmita A. , Friend John , Ratledge Colin 
Published: November 2006

AbstractWhen the sewage fungus Leptomitus lacteus was grown in liquid culture aerobically and then transferred to medium containing long‐chain fatty acids, it produced a number of oxygenated fatty acids. From linoleic acid (18∶2n−6), the major metabolite produced was R‐8‐hydroxy‐9Z,12Z‐octadecadienoic acid (8R‐HODE), with additional quantities of 8,11‐di‐HODE, 11,16‐di‐HODE, and 11,17‐di‐HODE. Other fatty acid derivatives identified included 7‐HODE, 10‐HODE, and 13‐hydroxy‐octadecamonoenoic acid. Arachidonic acid (20∶4n−6) was metabolized primarily to 18‐ and and 19‐hydroxy‐eicosatetraenoic acids (18‐ and 19‐HETE) also as R enantiomers, along with smaller quantities of 17‐HETE, 9‐HETE, 14,15‐dihydroxyeicosatrienoic acid and 11,12,19‐trihydroxy‐eicosatrienoic acid. The oxygenated products of long‐chain fatty acids, in particular the biosynthesis of 8R‐HODE, a compound classified as a precocious sporulation inducer, were similar to those produced by an unrelated fungal species in the Ascomycota, the take‐all fungus Gaeumannomyces graminis. As in G. graminis, the biotransformation of linoleate to 8R‐HODE was not significantly inhibited by exposure of the organism to CO. This indicated that the enzyme responsible for 8R‐HODE biosynthesis in Leptomitus could be similar to that of G. graminis; yet we did not detect 7,8‐di‐HODE as a product of 18∶2n−6 metabolism as in G. graminis. CO did inhibit the biosynthesis of 14,15‐di‐HETE, 18‐HETE, and 19‐HETE in L. lacteus, which suggested the involvement of a cytochrome P450‐type monooxygenase. The biosynthesis of 8R‐HODE from 18∶2n−6 was found to occur in certain cell lysates, specifically in low speed (15,000×g) supernatant, following cell disruption.
Fatty acid transport across lipid bilayer planar membranes
Authors: Romano‐Fontes L. G. , Curi R. , Peres C. M. , Nishiyama‐Naruke A. , Brunaldi K. , Abdulkader F. , Procopio J. 
Published: November 2006

AbstractThe transport of palmitic acid (PA) across planar lipid bilayer membranes was measured using a high specific activity [14C]palmitate as tracer for PA. An all‐glass trans chamber was employed in order to minimize adsorbance of PA onto the surface. Electrically neutral (diphytanoyl phosphatidylcholine) and charged (Azolectin) planar bilayers were maintained at open electric circuit. We found a permeability to PA of (8.8±1.9)×10−6 cm s−1 (n=15) in neutral and of (10.3±2.2)×10−6 cm s−1 (n=5) in charged bilayers. These values fall within the order of magnitude of those calculated from desorption constants of PA in different vesicular systems. Differences between data obtained from planar and vesicular systems are discussed in terms of the role of solvent, radius of curvature, and pH changes.
Coordinate packaging of newly synthesized phosphatidylcholine and phosphatidylglycerol in lamellar bodies in alveolar type II cells
Authors: Chander Avinash , Sen Namita , Wadsworth Sandra , Spitzer Alan R. 
Published: November 2006

AbstractMethylamine, a weak base, inhibits packaging of newly synthesized phosphatidylcholine (PC) in lamellar bodies in 20–22 h cultured alveolar type II cells, suggesting a role for acidic pH of lamellar bodies. In this study, we tested if (i) the packaging of PC is similarly regulated in freshly isolated type II cells and (ii) methylamine also inhibits the packaging of other surfactant phospholipids, particularly, phosphatidylglycerol (PG). The latter would suggest coordinated packaging so as to maintain the phospholipid composition of lung surfactant. During the short‐term metabolic labeling experiments in freshly isolated type II cells, methylamine treatment decreased the incorporation of radioactive precursors into PC, disaturated PC (DSPC), and PG of lamellar bodies but not of the microsomes, when compared with controls. The calculated packaging (the percentage of microsomal lipid packaged in lamellar bodies) of each phospholipid was similarly decreased (∼50%) in methylamine‐treated cells, suggesting coordinated packaging of surfactant phospholipids in lamellar bodies. Equilibrium‐labeling studies with freshly isolated type II cells (as is routinely done for studies on surfactant secretion) ± methylamine showed that in methylamine‐treated cells, the secretion of PC and PG was decreased (possibly due to decreased packaging), but the phospholipid composition of released surfactant (measured by radioactivity distribution) was unchanged; and the PC content (measured by mass or radioactivity) of lamellar bodies was lower, but the PC composition (as percentage of total phospholipids) was unchanged when compared with control cells. We speculate that the newly synthesized surfactant phospholipids, PC, DSPC, and PG, are coordinately transported into lamellar bodies by a mechanism requiring the acidic pH, presumably, of lamellar bodies.
The metabolism and distribution of docosapentaenoic acid (n−6) in rats and rat hepatocytes
Authors: Tam Phyllis S. Y. , Umeda‐Sawada Rumi , Yaguchi Toshiaki , Akimoto Kengo , Kiso Yoshinobu , Igarashi Osamu 
Published: November 2006

AbstractIn this study, a new marine oil that contains 45% docosahexaenoic acid (DHA, 22∶6n−3) and 13% docosapentaenoic acid (DPA, 22∶5n−6) was administered to rats. The metabolism and distribution of DPA in rats was investigated. In experiment 1, the effects of DHA and n−6 fatty acids (linoleic acid, I A; arachidonic acid, AA; and DPA) on AA contents were investigated in vivo. LA group: LA 25%, DHA 30%; LA‐DPA group: LA 15%, DPA 10%, DHA 35%; LA‐AA‐DPA group: LA 10%, AA 5%, DPA 10%, DHA 35% were administered to rats for 4 wk. In the liver, the AA content in the LA‐DPA and LA‐AA‐DPA groups was significantly higher than in the LA group. The decreased AA contents in the LA group might be caused by DHA administration. Although DHA also was administered in the LA‐DPA and LA‐AA‐DPA groups, the AA contents in these two groups did not decrease. These results suggested that DPA retroconverted to AA, blunting the decrease in AA content caused by DHA administration. To conduct a detailed investigation on DPA metabolism and its relation with AA and DHA, rat hepatocytes were cultured with pruified DPA and DHA for 24 h. We discovered the retroconversion of DPA to AA occurred only when AA content was decreased by a high DHA administration; it did not occur when AA content was maintained at a normal level.