Metabolism of fatty acids in fish. II. Biosynthesis of fatty acids in relation to diet in the carp, Cyprinus carpio Linnaeus 1758     

Tibor Farkas  István Csengeri  Ferenc Majoros  János Oláh 《Aquaculture (Amsterdam, Netherlands)》1978,14(1):57-65

Carp, weighing 15–25 g, were maintained in the laboratory on a control diet, or on diets prepared from wheat or corn, and the incorporation of sodium (1?¹⁴C)-acetate into their liver total fatty acids as well as into liver triglycerides and phospholipids was followed. The control diet was characterized by a high concentration of total lipids and linolenic acid, and the other two feeds by a low concentration of total lipids including linolenic acid and high concentration of carbohydrates. The highest rate of fatty acid biosynthesis was observed in fish given the corn diet, and the lowest rate was found in the carp on the control diet. Levels of radioactivity became very high in triglycerides of corn-fed fish. The major products of fatty acid biosynthesis were palmitic and oleic acids, in the corn-fed fish, while in the control fish almost 50% of the total radioactivity was in the long chain polyunsaturated fatty acids. The degree of labeling of oleic and palmitic acids appeared to depend on the level of linolenic acid in the diet. The results suggest that about 1% of linolenic acid in the diet is required to keep lipogenesis at a low level as well as to prevent hyperproduction of oleic acid. Linoleic acid seems to play a subordinate role in regulating lipogenesis in carp liver.  相似文献   

Very-high-energy gamma rays from a distant quasar: how transparent is the universe?     

MAGIC Collaboration  Albert J  Aliu E  Anderhub H  Antonelli LA  Antoranz P  Backes M  Baixeras C  Barrio JA  Bartko H  Bastieri D  Becker JK  Bednarek W  Berger K  Bernardini E  Bigongiari C  Biland A  Bock RK  Bonnoli G  Bordas P  Bosch-Ramon V  Bretz T  Britvitch I  Camara M  Carmona E  Chilingarian A  Commichau S  Contreras JL  Cortina J  Costado MT  Covino S  Curtef V  Dazzi F  De Angelis A  De Cea Del Pozo E  de Los Reyes R  De Lotto B  De Maria M  De Sabata F  Mendez CD  Dominguez A  Dorner D  Doro M  Errando M  Fagiolini M 《Science (New York, N.Y.)》2008,320(5884):1752-1754

The atmospheric Cherenkov gamma-ray telescope MAGIC, designed for a low-energy threshold, has detected very-high-energy gamma rays from a giant flare of the distant Quasi-Stellar Radio Source (in short: radio quasar) 3C 279, at a distance of more than 5 billion light-years (a redshift of 0.536). No quasar has been observed previously in very-high-energy gamma radiation, and this is also the most distant object detected emitting gamma rays above 50 gigaelectron volts. Because high-energy gamma rays may be stopped by interacting with the diffuse background light in the universe, the observations by MAGIC imply a low amount for such light, consistent with that known from galaxy counts.  相似文献   

Measuring fluctuating asymmetry of the terrestrial isopod Trachelipus rathkii (Crustacea: Isopoda, Oniscidea)   总被引：1，自引：0，他引：1  

Ferenc Vilisics  Pter Slymos  Elisabeth Hornung 《European Journal of Soil Biology》2005,41(3-4):85-90

Studies on fluctuating asymmetry (FA) in soil invertebrates, particularly in isopods, are almost absent so far. As a result, methodology of measuring FA in isopods is little known. However, the ecological importance of these animals in decomposition processes and the fact that FA in soil invertebrates might serve as an indicator of environmental stress, e.g. soil pollution, make the topic worth for investigation. Our results revealed that woodlice are potentially able to signal environmental stresses via FA. We compared six traits (length of three segments of antennae, two segments of the seventh legs and the number of ocelli) between two populations (Hungary: Hajós, Blaskovics-puszta) and genders of the species Trachelipus rathkii living under different environmental stresses (i.e. changing humidity). Asymmetry was significantly higher in the Hajós population, where the soil moisture has changed dramatically for the last years. Asymmetry was lower in Blaskovics-puszta, where the habitat has remained constant during the last centuries and the population had time to adapt to seasonally changing environments. Gender did not have an effect on FA. Traits differed significantly from each other, thus it is advisable to use several traits simultaneously to detect FA. FA was higher in the a1 segment of the antennal flagellae than in the ischium of the pereiopod and ocelli. We also studied the effect of regeneration of lost body parts on the FA values. Asymmetry in the treated groups was significantly higher than in the control ones. This calls the attention to the problem of outliers, which may be caused by physical harm and can lead to artificial results.  相似文献   

Composition of terrestrial isopod assemblages along an urbanisation gradient in Denmark     

Ferenc Vilisics  Zoltán Elek  Gábor L. Lövei 《Pedobiologia》2007,51(1):45-53

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Synthesis of haptens and protein conjugates for the development of immunoassays for the insect growth regulator fenoxycarb.     

Ferenc Szurdoki  András Székács  Hong M Le  Bruce D Hammock 《Journal of agricultural and food chemistry》2002,50(1):29-40

Sensitive and selective enzyme-linked immunosorbent assays (ELISAs) in the immobilized antigen format were developed for fenoxycarb (1), an insect growth regulator (IGR). The parent molecule [ethyl 2-(4-phenoxyphenoxy)ethylcarbamate] was derivatized at several positions to obtain haptens (2-5) that were used to produce protein conjugates and rabbit polyclonal antisera. Amino derivatives of fenoxycarb at the terminal and internal rings (2 and 3, respectively) were linked to carrier proteins by azo coupling. Carboxyalkyl-spacer groups were attached to the ethyl group and the nitrogen atom of the target compound (1) to obtain haptens 4 and 5, respectively. Hapten-homologous ELISAs based on protein conjugates of compounds 2 and 4 determined fenoxycarb in the mid-ppb range (IC(50), 102 and 95 ppb, respectively). A more sensitive hapten-heterologous ELISA (IC(50), 17 ppb; detection limit 0.5 ppb) involved the antiserum raised against a conjugate of hapten 2 and the plate-coating antigen obtained from compound 3. These assays displayed no significant interferences with photodegradation products of fenoxycarb, the IGRs methoprene and pyriproxyfen, and a variety of pesticides including the pyrethroids fenvalerate and cypermethryn, the phenoxyacetic acid herbicide 2,4-D, DDT, and the nitrodiphenyl ether herbicides acifluorfen and fluorodifen.  相似文献   

Chain Extension and Termination as a Function of Cysteine Content and the Length of the Central Repetitive Domain in Storage Proteins     

Lszl Tams  Peter W. Gras  Robert G. Solomon  Matthew K. Morell  Rudi Appels  Ferenc Bks 《Journal of Cereal Science》2002,36(3):313

Analogue glutenin proteins (ANGs) based on the barley seed storage protein C-hordein, modified to contain N- and/or C-terminal cysteine residues and varying lengths of repetitive domain, have been purified from a bacterial expression system. The proteins were used to modify the mixing, extension and baking properties of wheat flour doughs in small-scale tests. Comparison of the effects of simple addition of the proteins versus their chemical incorporation into the glutenin macropolymer has allowed us to assess the importance of cysteine content, cysteine position and repetitive domain length in determining dough mixing and processing properties. When incorporated, the proteins, along with small synthetic oligopeptides based on their N- and C-terminal sequences, change the amount of large glutenin polymers, and hence dough properties, in ways consistent with their action as either chain terminators (polypeptides with single cysteine residues) or chain extenders (polypeptides with two cysteine residues, one in either terminal domain). The gross effects of chain extension and termination may be further fine-tuned by modification of the molecular size of the incorporated proteins through alteration of their repetitive domains.  相似文献   

Effect of acetylation on the chemical composition of hornbeam (Carpinus betulus L.) in relation with the physical and mechanical properties     

Fanni Fodor  Róbert Németh  Chiel Lankveld  Tamás Hofmann 《Wood material science & engineering》2018,13(5):271-278

Common hornbeam (Carpinus betulus L.) is a highly underused wood species despite its great hardness, strength, wear-resistance and toughness. It is mainly used as firewood in Hungary because of its wood defects, irregular shape and low-dimensional stability. These wood defects and small breast height diameter result in a low yield. It is non-durable outdoors as it tends to turn grey, crack and be attacked by wood-decaying organisms. Indoors it lasts for hundreds of years. One technology that could improve the stability and durability properties is acetylation. Hornbeam was acetylated with the Accoya® method under industrial conditions. The aim of this research was the assessment of acetylation affecting the chemical properties of hornbeam wood and how these are related to the change in physical and mechanical properties. Main wood constituents (cellulose, hemicellulose, Klason lignin, extractives and ash content) were determined and compared. Chemical parameters related to the degradation of structural polymers were also evaluated (total phenolic and soluble carbohydrate contents, pH and buffering capacity, furfural, levulinic acid, formic acid, acetic acid). Structural changes in acetylated wood and in the Klason lignin fraction were also assessed using FTIR spectroscopy.  相似文献   

Depolymerization of the Glutenin Macropolymer During Dough Mixing: I. Changes in Levels,Molecular Weight Distribution,and Overall Composition     

John H. Skerritt  Luch Hac  Ferenc Bekes 《Cereal Chemistry》1999,76(3):395-401

Changes in the amounts, molecular weight distributions, and levels of major groups of subunits in the glutenin macropolymer (GMP) of doughs during mixing were investigated. The GMP (gel protein) is the unreduced fraction of gluten protein that remains as a layer on top of the starch after extraction of SDS-soluble proteins and centrifugation. Experiments involved doughs prepared from flours derived from one weak and one strong cultivar and lines derived from cv. Olympic that were null for specific high molecular weight glutenin subunits (HMW-GS). During mixing, the amount of GMP decreased; the major changes occurred before peak mixing time (MT, achievement of peak resistance). In addition, the average apparent molecular weight of GMP (determined by both size-exclusion HPLC and multilayer gel electrophoresis) decreased during mixing, but in this case, the major changes were seen later in the mixing process, during dough breakdown. Even after extensive mixing, polymers and oligomers were released, not free glutenin subunits. During dough breakdown, the composition of GMP also changed, such that the proportion of HMW-GS decreased but β-amylases/D low molecular weight glutenin subunits (LMW-GS) increased. Changes in the total amounts of other LMW-GS typically were smaller with a decrease in the proportion of B subunits and an increase in the proportion of C subunits. The major changes in GMP composition were observed after peak MT (peak resistance) occurring earlier and to a greater extent in the weaker dough. Our results suggest that dough breakdown during mixing may be triggered by loss of HMW-GS, leading to changes in the molecular weight distribution and composition of the disulfide-bonded GMP.  相似文献   

Depolymerization of the Glutenin Macropolymer During Mixing: II. Differences in Retention of Specific Glutenin Subunits     

John H. Skerritt  Luch Hac  Megan P. Lindsay  Ferenc Bekes 《Cereal Chemistry》1999,76(3):402-409

The depolymerization of individual high and low molecular weight (HMW and LMW, respectively) glutenin subunits (GS) from the glutenin macropolymer (GMP) in doughs during mixing was investigated by reversed-phase (RP) HPLC and SDS-PAGE. Cultivars with different dough strengths, as well as lines null for specific HMW-GS and biotypes differing at individual HMW-GS and LMW-GS encoding loci, were studied. During mixing, the proportion of total HMW-GS in GMP decreased, and the ratios of different subunits in the GMP in doughs changed. There was a loss of chromosome 1B- and 1D-encoded x-HMW-GS, while the relative proportions of y-HMW-GS (among HMW-GS) increased. Changes in 1B subunits occurred first, while most of the changes in 1D HMW-GS content occurred during dough breakdown. Changes were more pronounced for doughs of weak to average strengths than for stronger doughs. RP-HPLC analysis demonstrated a consistent increase in the retention times (surface hydrophobicity) of chromosome 1D-encoded HMW-GS but not of other HMW-GS or LMW-GS during mixing. SDS-PAGE and RP-HPLC demonstrated that specific B subunits, typically those with lower hydrophobicity, were selectively depolymerized from the GMP during dough breakdown, while the proportions of specific C subunits, typically those with greater hydrophobicity, increased. Similar trends were seen in analyses of several pairs of biotypes differing at single LMW-GS encoding loci, although there were slight differences in the depolymerization behavior of wheats with different allelic compositions. The results suggest that dough breakdown may be triggered by the loss of specific HMW-GS from the GMP, and a structural hierarchy may exist for different LMW-GS within glutenin in doughs.  相似文献