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Recupero e valorizzazione dei sottoprodotti della pesca come fonti di acidi grassi polinsaturi n-3
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Stereospecific analysis of triacylglycerols in mare's milk [Indagine sulla struttura trigliceridica del latte di giumenta]
No full textFatty acids composition of mare milk triacylglycerols (TGs) was studied at three different lactation stages. Stereospecific analysis of TGs was carried out with Chemical deacylation and enzymatic hydrolysis to determine the fatty acids distribution on the glycerol backbone as the TG structure are of importance when considering the biological functions, the nutritional value as well as the echnological properties of milk lipids. Milk samples showed a high content of EFA, about 25% of the total fatty acid composition. In all considered lipid fraction saturated fatty acids (SFA), especially about 50% to 70% of C8:0 and C10:0, were prevalently esterified at the sn-2 position. Unsaturated fatty acids (UFA) occupied essentially the sn-(1,3) position; on average only 21.2% of C18:3ω3 and 19% of C18:2 were localized at the sn-2 position
A regulatory mutant of Hansenula polymorpha exhibiting C1-peroxisomes under glucose growth
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Mutations affecting the expression of the MOX gene encoding peroxixomal methanol oxidase in Hansenula polymorpha.
No full textIn this study, aimed at identifying genetic factors acting positively upon the MOX gene, we report the isolation and characterisation of several methanol utilisation-defective (Mut-) mutants of Hansenula polymorpha. These fall into 12 complementation groups, eight of which show significant reductions in alcohol (methanol) oxidase activity in methanol. Three of these groups, identifying the MUT3, MUT5 and MUT10 loci, exhibit extremely low levels of MOX promoter activity, not only in methanol medium, but also during growth in glycerol or methylamine. We suggest that these loci play a significant role in the derepression of the MOX gene expression. One of these genes (MUT10) also seems to be involved in the utilisation of carbon sources other than methanol, and it is apparent that the same gene plays some role in the biogenesis or in the enlargement of the peroxisome. Three other genes (MUT7, MUT8 and MUT9) appear to be involved in peroxisome biogenesis, whereas most other mutants harbour lesions that leave the peroxisome biogenesis and proliferation unaffected
Caratterizzazzione chimica della mandorla del nocciolo dell’oliva
No full textI sistemi tecnologici attualmente utilizzati per l’estrazione dell’olio di oliva sono diversi.
E’ di recente introduzione una nuova tecnologia di estrazione che prevede la preventiva denocciolatura delle olive.
Studi sperimentali volti a confrontare i parametri fisici, chimici e organolettici degli oli ottenuti dalla drupa intera con quelli ottenuti dalla sola polpa evidenziano come questi ultimi risultino caratterizzati da una maggiore resistenza all’ossidazione forzata e da un corredo di molecole di natura fenolico più complesso.
Il presente lavoro volge l’attenzione verso la caratterizzazione chimica della mandorla del nocciolo dell’oliva al fine di caratterizzare nuove molecole con attività antiossidante e di evidenziare differenze compositive, in funzione della cultivar.
A tale scopo è stato esaminato l’estratto lipidico della mandorla di due differenti cultivar di olive tipiche della Calabria, quali Carolea e Tondina. La composizione in acidi grassi degli estratti è stata determinata mediante analisi gascromatografica mentre la caratterizzazione delle specie molecolari fosfolipidiche e glicolipidiche è stata effettuata utilizzando un sistema HPLC accoppiato on-line ad uno spettrometro di massa, equipaggiato con interfaccia ad elettronebulizzazione, operante in ionizzazione negativa (HPLC-ESI-MS-MS).
Dall’esame dei risultati non emergono differenze significative nella composizione acidica e nella composizione della frazione fosfolipidica e glicolipidica e fenolica degli estratti lipidici ottenuti dalle due varietà
Stereospecific analysis of triacylglycerols in camel (Camelus dromedarius) milk fat
No full textIn the lipid fraction of camel (Camelus dromedarius) milk the percentage of saturated fatty acids (SFAs) was 62.8% with a content of palmitic acid of 28.5%. The unsaturated fatty acid (UFA) fraction was dominated by oleic and palmitoleic acids. Enzyme digestion and chemical degradation methods were used to determine the intramolecular fatty acid (FA) composition and then the intermolecular FA distribution in the three sn-positions of the triacylglycerols of the camel milk. FAs showed a specific preference for a particular position: in all samples studied, SFAs were prevalently esterified in the sn-2 position, while UFAs occupied mainly the sn-1 and sn-3 position. As the carbon chain lengthened from 8 to 16 the percentages of SFAs decreased in the sn-2 position and increased in the outer positions. Such data indicated that the length of the carbon chain could be a discriminating factor in the acylation process of SFAs
Electrospray ionization tandem mass spectrometry analysis of triacylglycerols molecular species in camel milk (Camelus dromedarius)
No full textCamel (Camelus dromedarius) milk fat triacylglycerols (TAGs) were characterized using high performance liquid chromatography, electrospray ionization mass spectrometry and high temperature gas chromatography. The complex nature of the fat meant that prefractionation was necessary to provide simpler fractions for more detailed molecular analyses. Data showed that camel fat contained a wide variety of molecular weight species. No predominant TAG was synthesized by the mammary gland. Of the quantified TAGs, 99% contained at least one of the four major fatty acids (FAs), i.e., C14:0, C16:0, C18:0, C18:1 (that by themselves represented 74% of the total FAs), and about 75% contained at least one unsaturated FA. Experimentally determined distributions of TAG molecular weights deviated from distributions predicted by a random hypothesis method. Mixed TAGs containing C-14, C-16 and C-18 FAs were preferentially synthesized by the mammary gland to the detriment of TAGs rich in medium chain FAs or long chain FAs alone
Vanadium affects vacuolation and phosphate metabolism in Hansenula polymorpha
No full textThe yeast Hansenula polymorpha is able to grow on vanadate concentrations that are toxic to other organisms. Transmission electron microscopy analysis showed that H. polymorpha cells growing on a vanadate-containing medium undergo a significant increase in cell vacuolation and a thickening of the cell wall; the presence of small cytoplasmic vesicles and an increase in cristae at the level of the plasma membrane were also observed. These ultrastructural modifications were accompanied by a change in the intracellular polyphosphate level, as shown by in vivo 31P-NMR. The involvement of these observed changes in vanadium detoxification is discussed
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