Uloga izomera α-, γ- i δ-tokoferola u bifaznoj kinetici uklanjanja DPPH radikala iz uzoraka bučinog ulja i uljnih mješavina

The antioxidant activity of three types of pumpkin seed oil or oil mixtures (cold-pressed, produced from roasted seed paste and salad) produced in the northern part of Croatia and the kinetics of their behaviour as free radical scavengers were investigated using DPPH˙. In addition, the involvement of oil tocopherol isomers (α-, γ- and δ-) in different steps of DPPH˙ disappearance and their impact on the rate of reaction were analysed. The kinetics of DPPH˙ disappearance is a two-step process. In the first step, rapid disappearance of DPPH˙ occurs during the first 11 min of the reaction, depending on the oil type, followed by a slower decline in the second step. To describe DPPH˙ disappearance kinetics, six mathematical models (mono- and biphasic) were tested. Our findings showed that γ- and δ-tocopherols affected DPPH˙ disappearance during the first step, and α-tocopherol in the second step of the reaction. Moreover, α-tocopherol demonstrated 30 times higher antioxidant activity than γ- and δ-tocopherols. The results indicated the biphasic double-exponential behaviour of DPPH˙ disappearance in oil samples, due to the complexity of reactions that involve different tocopherol isomers and proceed through different chemical pathways.U ovom su radu ispitani antioksidacijska aktivnost i kinetika uklanjanja DPPH radikala iz bučinih ulja ili uljnih mješavina (iz hladno-prešanog, zatim ulja dobivenog prešanjem prženih bučinih sjemenki i salatnog ulja), proizvedenih na području Sjeverne Hrvatske. Osim toga, ispitan je utjecaj različitih izomera vitamina E (α-, γ- i δ-tokoferola) na brzinu reakcije tijekom različitih stupnjeva nestanka DPPH radikala iz tih ulja. Postupak uklanjanja radikala odvija se u dva stupnja: u prvom stupnju se tijekom početnih 11 minuta reakcija odvija brzo, nakon čega slijedi sporiji, drugi stupanj. Za opisivanje kinetike nestanka radikala upotrijebljeno je šest monofaznih i bifaznih matematičkih modela. Iz dobivenih se rezultata može zaključiti da γ- i δ-izomeri tokoferola sudjeluju u prvom stupnju, dok je α-tokoferol uključen u drugi stupanj procesa uklanjanja radikala. Osim toga, utvrđeno je da α-tokoferol ima 30 puta veću antioksidacijsku aktivnost od γ- i δ-izomera. Rezultati pokazuju da je bifazna kinetika nestanka DPPH radikala posljedica niza složenih reakcija koje se odvijaju različitim mehanizmima, a u kojima sudjeluju izomeri tokoferola

Effect of dietary fatty acid variation on mice adipose tissue lipid content and phospholipid composition

The objective of our research was to determine the effects of five different diets as a source of various groups of fatty acids on mice adipose tissue lipid content, phospholipid composition and fatty acid composition of adipose tissue total lipids and phospholipids. Beside the standard diet, diets enriched either with pumpkin-seed, olive or fish oil or lard were used for feeding wild type C57Bl/6 male mice aged 8-10 weeks for 3 weeks. In mice fed with diets enriched with oils/lard, relative adipose tissue mass decreased, comparing to standard diet fed mice. Adipose tissue total lipid content decreased significantly in olive and fish oil diet comparing to pumpkin-seed oil and standard diet. Analysis of the phospholipid classes showed that phosphatidylcholine, phosphatidylethanolamine, phosphatidylserine and sphingomyelin were common components in all diet types. The dominant storage form of fatty acids in adipose tissue total lipids were unsaturated fatty acids (oleic and linoleic acid prevailed), while in phospholipids, C18 acids prevailed (stearic acid was the main fatty acid) in all diets. Enrichment of the diet with specific oil or lard significantly changed the n-6/n-3 ratio. Fish oil diet provoked the highest reduction of that ratio, both in adipose tissue total lipids and in phospholipids. Obtained results imply that diet modification has an influence on adipose tissue lipid content and composition as well as remodelling process occurring in the adipose tissue phospholipids

The Effect of Low Temperature Storage on the Lipid Composition of Baker\u27s Yeast

Production of frozen dough demands the usage of freezing/thawing resistant strains of baker\u27s yeast that can adapt to low temperature and preserve fermentative performance, which is closely related to the lipid composition of their cells. In order to determine the effect of low temperature storage on the baker’s yeast, we have analysed lipids of compressed commercial baker’s yeast of Saccharomyces cerevisiae strain maintained at 4 °C (7 and 14 days) and -20 °C (7, 14 and 120 days). In the phospholipid composition of all groups the most abundant was phosphatidylcholine (42 – 56 % of total phospholipids), followed by phosphatidylinositol (21 – 28 %). Phosphatidylcholine to phosphatidylethanolamine ratio, one of the parameters of the adaptation capability to extracellular changes, was high (2.4 – 3.3). Sterol esters and ergosterol were the most abundant neutral lipids in all groups. Oleic and palmitoleic acids were by far the most abundant fatty acids in all groups (39 – 48 % and 33 – 38 % of total cell fatty acids, respectively). Compared to the fresh yeast, considerable differences were found in the composition of all three lipid classes in the samples maintained at both temperatures. The major changes were observed after 14 days of exposure to -20 °C

Kinetic Evaluation of Imidacloprid Degradation in Mice Organs Treated with Olive Oil Polyphenols Extract

Imidacloprid is a highly effective insecticide, acting as agonists at the insect nicotinic acetylcholine receptor. Nevertheless, imidacloprid itself or its metabolites could exhibit toxicity in mammals. Imidacloprid biotransformation involves oxidative cleavage, releasing the 6-chloronicotinic acid. Therefore, the concentration of imidacloprid and 6-chloronicotinic acid was used to characterize degradation kinetics and distribution of imidacloprid in mice liver, kidneys and lungs. Additionally, the influence of olive oil polyphenols on imidacloprid metabolism was evaluated. Experimental animals were divided into three groups: control, IMI – imidacloprid treated mice (5 mg/kg) and (IMI + PP) – mice treated with polyphenols (10 mg/kg) for seven days before the administration of imidacloprid. Neither imidacloprid nor 6-chloronicotinic acid could be detected 48 hours after administration in IMI group, while complete degradation in the (IMI + PP) group was accomplished within 24 hours. Significantly higher rate constant and shorter half-life in (IMI + PP) group emphasize that polyphenols may diminish the toxicity of this pesticide

Utjecaj okolišnih čimbenika stresa i recikliranja na lipidni sastav mitohondrija pivskog kvasca

The aim of this study was to investigate alterations in the content and composition of mitochondrial lipids of brewer’s yeast, which occur during brewing and repetitive recycling. The bottom-fermenting brewer’s yeast of Saccharomyces cerevisiae species obtained from industrial beer production was used throughout the study. The first three generations of recycled yeast were analysed. Differences between the generations were more pronounced in the phospholipid and neutral lipid composition than in fatty acid composition. Squalene was present in all generations in high concentrations. The results give insight into the response of yeast cells to stress factors and recycling. This work is licensed under a Creative Commons Attribution 4.0 International License.Cilj istraživanja bio je odrediti promjene u sadržaju i sastavu lipida mitohondrija pivskog kvasca do kojih dolazi za vrijeme vrenja i recikliranja biomase. U radu je upotrijebljen pivski kvasac donjeg vrenja vrste Saccharomyces cerevisiae dobiven u industrijskom procesu. Analizirane su prve tri generacije recikliranog kvasca. Razlike između pojedinih generacija bile su izraženije u sastavu fosfolipida i neutralnih lipida nego u sastavu masnih kiselina. Skvalen je u svim generacijama bio prisutan u relativno visokoj koncentraciji. Rezultati istraživanja pružaju uvid u odgovor stanica kvasca na stresne faktore i recikliranje. Ovo djelo je dano na korištenje pod licencom Creative Commons Imenovanje 4.0 međunarodna

CYFRA 21-1 Protein - a Potential Marker of Endometriosis

Endometrioza je kronična upalna bolest karakterizirana pojavom i rastom endometrija izvan maternice. Etiopatogeneza nije razjašnjena, a postoji više teorija nastanka endometrioze. Patološki procesi prisutni u endometriozi jesu adhezija, invazija, proliferacija, angiogeneza i promijenjena imunost. Moguće je da procesi invazije i proliferacije uzrokuju povećanu sintezu određenih proteina koji se zatim izlučuju urinom. Protein citokeratin 19-9 (CYFRA 21-1) pojačano se izlučuje u urinu pacijentica s endometriozom te je potencijalni marker u ranim stadijima ove bolesti kada nije moguće slikovnim metodama postaviti sumnju na bolest ili ciljanu dijagnozu.Endometriosis is a chronic gynaecological inflammatory disease characterized by the appearance and flourishing of endometrium outside the uterine cavity. The etiopathogenesis is not yet clearly understood. The ongoing pathologic processes are invasion, adhesion, proliferation, angiogenesis, and immune dysfunction. There is a possibility of increased production of proteins caused by proliferation and invasion, that are excreted in the urine. The protein CYFRA 21-1 shows increased production in endometriosis and is a potential marker in the early stages of this disease when it is not possible to suspect the disease or diagnose it with imaging techniques

Lipid Composition of Sheffersomyces stipitis M12 Strain Grown on Glycerol as a Carbon Source

Pozadina istraživanja. U ovom je istraživanju određen sadržaj i sastav lipida u soju kvasca Sheffersomyces stipitis M12 s narušenom biosintezom ergosterola, uzgojenom na glicerolu kao izvoru ugljika. Zaustavljanje biosintetskog puta ergosterola jedna je od metoda koja se u novije vrijeme primjenjuje za povećanje udjela S-adenozil-L-metionina (SAM) u biomasi kvasca. Eksperimentalni pristup. Šaržni je uzgoj kvasca M12 proveden aerobno u laboratorijskom bioreaktoru, s glicerolom kao izvorom ugljika i uz pulsni dodatak metionina. Koncentracija glicerola i maseni udjel SAM-a određeni su tekućinskom kromatografijom visoke djelotvornosti, dok je masnokiselinski sastav svih klasa lipida, odijeljenih ekstrakcijom na čvrstoj fazi, utvrđen plinskom kromatografijom. Rezultati i zaključci. Usprkos manjem udjelu ergosterola u kvascu M12, zbog reorganizacije metabolizma lipida ostvareni su veliki prirast biomase i prinos SAM-a. U tom soju kvasca prevladavali su neutralni lipidi (više od 75 % ukupnih lipida), no njihov sadržaj i sastav bio je značajno izmijenjen u odnosu na divlji tip kvasca. Nezasićene i C18 masne kiseline prevladavale su u obje vrste kvasca. U svim je frakcijama, osim u frakciji slobodnih masnih kiselina, indeks nezasićenosti bio niži u soju M12 u usporedbi s divljim tipom kvasca. Soj M12 je u promijenjenim uvjetima rasta nesmetano funkcionirao i zadovoljio sve svoje energetske potrebe mijenjanjem sastava lipida (osobito fosfolipida, sterola i sterolnih estera) i ugađanjem njihove nezasićenosti. Novina i znanstveni doprinos. U radu je prikazan proces reorganizacije sastava lipida kvasca S. stipitis s narušenim metaboličkim putem biosinteze ergosterola. Konstruiran je i shematski prikazan aktualni metabolizam lipida tijekom aktivne proizvodnje SAM-a u kvascu S. stipitis uzgojenom na glicerolu kao izvoru ugljika. Ove spoznaje o metabolizmu lipida mogu se iskoristiti kao vrijedan alat u daljnjem unapređivanju primjene kvasca S. stipitis kao modelnog organizma, te omogućiti njegovu uporabu u primijenjenim istraživanjima.Research background. In this study the content and composition of lipids in ergosterol-reduced Sheffersomyces stipitis M12 strain grown on glycerol as a carbon source is determined. Blocking the ergosterol synthesis route in yeast cells is a recently proposed method for increasing S-adenosyl-l-methionine (SAM) production. Experimental approach. The batch cultivation of M12 yeast was carried out under aerobic conditions in a laboratory bioreactor with glycerol as carbon source, and with pulsed addition of methionine. Glycerol and SAM content were monitored by high-performance liquid chromatography, while fatty acid composition of different lipid classes, separated by solid phase extraction, was determined by gas chromatography. Results and conclusion. Despite the reduced amount of ergosterol in yeast cells, thanks to the reorganized lipid metabolism, M12 strain achieved high biomass yield and SAM production. Neutral lipids prevailed (making more than 75 % of total lipids), but their content and composition differed significantly in the two tested types of yeast. Unsaturated and C18 fatty acids prevailed in both the M12 strain and wild type. In all fractions except free fatty acids, the index of unsaturation in M12 strain was lower than in the wild strain. Our tested strain adjusts itself by changing the content of lipids (mainly phospholipids, sterols and sterol esters), and with desaturation adjustments, to maintain proper functioning and fulfil increased energy needs. Novelty and scientific contribution. Reorganization of S. stipitis lipid composition caused by blocking the metabolic pathway of ergosterol synthesis was presented. A simple scheme of actual lipid metabolism during active SAM production in S. stipitis, grown on glycerol was constructed and shown. This fundamental knowledge of lipid metabolic pathways will be a helpful tool in improving S. stipitis as an expression host and a model organism, opening new perspectives for its applied research

Influence of stressful fermentation conditions on neutral lipids of a Saccharomyces cerevisiae brewing strain

The neutral lipid fraction of the aerobically grown starter yeast culture of a Saccharomyces cerevisiae brewing strain, and three-first recycled yeast generations exposed to multiple stress factors during beer fermentation was studied. No pronounced changes in the cellular neutral lipid content between the non-stressed starter and stressed recycled cells were found. However, it was found that recycled yeast generations modulate their neutral lipid composition during fermentation. The ergosterol content was increased at the expense of steryl esters (SEs) and squalene, which resulted in a higher ergosterol/SEs molar ratio and a slightly higher ergosterol/squalene molar ratio. In addition, the proportion of unsaturated fatty acids, mainly palmitoleic acid increased in the neutral lipid fraction of the stressed recycled yeast generations. These results suggest that some specific neutral lipid species and fatty acids stored in the neutral lipid fraction are involved in the adaptive response of the brewer's yeast to stressful fermentation conditions. The striking finding was a high squalene content in the neutral lipid fraction of both the starter yeast culture and recycled yeast generations (22.4 vs. 19-20%, respectively), implying a possible biotechnological exploitation of this biologically active molecule from the yeast biomass

Potential toxicity of titanium

Titanij se široko primjenjuje zbog svoje biokompatibilnosti i dobrih biomehaničkih svojstava. Pokazuje dobru sposobnost vezanja za živo tkivo i kosti pa se često upotrebljava za zubne, ortopedske i srčane implantate. Upotrebljava se kao čisti titanij ili kao legura na bazi titanija, gdje dodatak drugog elementa titaniju omogućuje dobivanje boljih svojstava od samoga titanija. Unatoč inertnosti, titanij je i dalje podložan koroziji i otpuštanju štetnih metalnih iona u organizam. Većina studija pokazuje da je titanij izrazito biokompatibilni materijal, međutim određene studije ukazuju da materijali od titanija mogu postati nekompatibilni i prouzročiti štetne učinke. S obzirom na široku upotrebu titanija, javljaju se pitanja o mogućoj štetnosti titanija. Stoga je važno i dalje provoditi toksikološka ispitivanja, pomno procijeniti i ispitati potencijalnu štetnost titanija te provjeriti potencijalne zdravstvenerizike za ljude i za ekosustav.Titanium is widely used due to its biocompatibility and good biomechanical properties. Often it is the material of choice for making dental, orthopaedic and heart implants because it has good binding ability to living tissue and bones. It is used as pure titanium or as a titanium alloys, where the addition of another element or more of them allows to obtain better properties than titanium itself. Despite its inertness, titanium is still susceptible to corrosion and the release of harmful metal ions into the body. Most studies show that titanium is a highly biocompatible material, however there are certain studies that show that titanium materials can become incompatible and cause harmful effects. Given the widespread use of titanium, questions arise about its possible harmfulness. It is therefore important to continue to conduct toxicological tests, to carefully evaluate and examine the potential harmfulness of titanium, and to check for potential health risks to humans and the ecosystem