Fatty Acid Unsaturation Index Research Articles

Tert-Butylhydroquinone retards longan fruit deterioration by regulating membrane lipid and energy metabolisms

Longan fruit deteriorates rapidly after harvest, which limits its storability. This study aimed to investigate the effect of tert-butylhydroquinone (TBHQ) on quality maintenance, membrane lipid metabolism, and energy status of longan fruit during 25 °C storage. Compared with control fruit, TBHQ treatment maintained better marketable fruit rate and suppressed activities of phospholipase D (PLD), lipase, and lipoxygenase (LOX), and downregulated expressions of DlPLD, DlLOX, and Dllipase. TBHQ also increased the ratio of unsaturated fatty acids to saturated fatty acids (U/S) and the index of unsaturated fatty acids (IUFA). In addition, higher levels of ATP, ADP, energy charge, NADP+/ NADPH as well as higher activities of H+-ATPase, Ca2+-ATPase and NADK were also observed in TBHQ-treated fruit. These results suggested that TBHQ may maintain postharvest quality of longan fruit by regulating membrane lipid and energy metabolisms.

Spraying L-phenylalanine during fruit development alleviates chilling injury in harvested muskmelons by regulating membrane lipid metabolism

L-phenylalanine (L-Phe) is an aromatic essential amino acid. Although postharvest L-Phe treatment can alleviate chilling injury (CI) of fruit by scavenging excessive reactive oxygen species (ROS), there are no reports on whether L-Phe spraying during fruit development affects the CI of harvested muskmelon by regulating membrane lipid metabolism. In this study, plants and fruit of muskmelon (cv. Manao) were sequentially sprayed with 8 mM L-Phe four times at the young fruit stage, early expansion stage, late expansion stage and mature stage. The effect of L-Phe spraying during fruit development on CI of harvested muskmelon fruit was studied and to the related mechanism of membrane lipid metabolism was investigated. The results showed that L-Phe sprays activated phospholipase A2 (PLA2) and increased the content of unsaturated fatty acids such as linoleic acid, linolenic acid and oleic acid, and improved the double bond index of unsaturated fatty acids (DBI) in harvested muskmelons during cold storage. L-Phe sprays inhibited the phospholipase C (PLC) and phospholipase D (PLD), increased the content of phosphatidylinositol (PI) and phosphatidylcholine (PC), but decreased the content of phosphatidic acid (PA) in harvested muskmelons during cold storage. In addition, L-Phe sprays inhibited lipoxygenase (LOX), reduced malondialdehyde (MDA) levels and cell membrane permeability, and effectively reduced the CI index of harvested muskmelons during cold storage. Taken together, L-Phe sprays during fruit development alleviated CI in harvested muskmelons by regulating membrane lipid metabolism.

Efficient production of Antrodin C by microparticle-enhanced cultivation of medicinal mushroom Antrodia cinnamomea

The microparticle-enhanced cultivation (MPEC) was used to enhance the production of Antrodin C by submerged fermentation of medicinal mushroom Antrodia cinnamomea. The crucial factors such as types, sizes, concentrations, and addition time of microparticles were optimized. The mechanism of MPEC on the membrane permeability and fluidity of A.cinnamomea and the expression of key genes in Antrodin C were investigated. When talc (18μm, 2g/L) was added into the fermentation liquid at 0h, the promoting effect on Antrodin C was the best. The maximum yield of Antrodin C was 1615.7mg/L, which was about 2.98 times of the control (541.7mg/L). Talc slightly damaged the mycelia of A.cinnamomea, increased the release of intracellular constituents, and enhanced the index of unsaturated fatty acid. In addition, the key genes (IDI, E2.3.3.10, HMGCR, atoB) that might play an important role in the synthesis of the triquine-type sesquiterpene Antrodin C, were upregulated. In conclusion, talc increased the permeability and fluidity of cell membrane, upregulated the key genes and improved the biosynthesis process to enhance the yield of Antrodin C in the submerged fermentation of A.cinnamomea.

Dietary (n-3) Polyunsaturated Fatty Acids Improve Adipocyte Insulin Action and Glucose Metabolism in Insulin-Resistant Rats: Relation to Membrane Fatty Acids

To study the effects of dietary fish oil on insulin-stimulated glucose metabolism in adipocytes of insulin-resistant rats (rats fed 50% sucrose and 30% fat), eighteen 5-wk-old Sprague-Dawley rats were fed, for 6 wk, a diet containing 30% fat as either fish oil (FO) or a mixture of vegetable and animal oils [control oils (CO)]. A third reference group was fed a standard diet (62% corn starch and 13% fat). At the end of the 6-wk period, the two experimental groups had comparable plasma glucose concentrations that were higher than that found in the reference group. FO feeding corrected the hyperinsulinemia of the experimental rats (P < 0.05) to reach values in the reference group. Plasma triacylglycerol (P < 0.01) and cholesterol (P < 0.001) concentrations were also lower in rats fed FO than in those fed CO. The body weights of FO-fed rats were similar to that of CO-fed rats, but epididymal adipose tissue weight was lower (P < 0.01). Adipocytes of FO-fed rats, compared with those of CO-fed rats, had high insulin-stimulated glucose transport (P < 0.05), oxidation (P < 0.001) and incorporation into total lipids (P < 0.05). The incorporation of (n-3) polyunsaturated fatty acids in adipocyte membrane phospholipids was higher in FO-fed rats than in those fed CO (P < 0.0001). Insulin action was positively correlated with the fatty acid unsaturation index in membrane phospholipids. Thus dietary fish oil has beneficial effects on insulinemia, plasma lipids and insulin-stimulated glucose metabolism in insulin-resistant slightly diabetic rats.

Особливості обміну омега-3/омега-6 жирних кислот у дітей з епілептичними енцефалопатіями та розладами аутистичного спектра

Purpose - to study the level of the serum fatty acids in children with autism spectrum disorders (ASD); to compare omega-6/omega-3 ratio depending of the clinical manifestation epileptic encephalopathy (EE) and ASD and electroencephalography data (EEG). Materials and methods. The study examined 101 children aged 2-6 years (mean age 4.02±0.95 years) with clinical manifestations ASD, who had been treated in a neuropsychiatric unit of the SI «Institute of Pediatrics, Obstetrics and Gynecology named after academician O.M. Lukyanova of the NAMS of Ukraine». According to the clinical features of epileptic encephalopathies and ASD, EEG monitoring data formed three groups: the group 1 - 35 children with clinical manifestations of ASD but without epileptic seizures and epileptiform changes in the EEG; the group 2 - 32 children with cognitive disintegration, clinical manifestations of ASD in which parents and health professionals did not note or noted a single history of epileptic seizures, but with epileptiform changes in the EEG; the group 3 - 34 children with clinical manifestations of ASD in which parents or health professionals have noted epileptic seizures and epileptiform changes in the EEG. In all children the level of blood fatty acids was determined by gas-liquid chromatography. Results. Indicators of fatty acid concentration indicate that the serum of children showed a significantly low level of omega-3 polyunsaturated fatty acids (PUFA) and saturation of omega-6 po PUFA in all groups of children. The level of concentration of the main metabolites of essential fatty acids reflects the imbalance due to deficiency of essential linolenic acid and its metabolite - docosapentaenoic acid, especially in children with ASD and epileptiform changes in the EEG (group 2), (p&lt;0.01). Among the omega-6 PUFA found a high content of essential linoleic acid and its metabolite - arachidonic acid, which causes the total excess of this group of PUFA, more pronounced in the groups 1 and 2. The level of index of unsaturated fatty acids in children from the group 1 was 10.1, in children from the group 2 - 9.8, and in the group 3 - 9.3. The obtained results of the assessment of the unsaturation index reflect the lower level of index of unsaturated fatty acids in children of the group 3 who have manifestations of ASD and epileptic seizures compared to other groups (p&lt;0.05, r=0.99). Conclusions. The data is a reliable evidence that children with ASD, epileptic seizures and epileptiform changes in the EEG have higher levels of omega-6 PUFA and arachidonic acid and omega-3 and docosahexaenoic acid deficiency. The most pronounced imbalance in both the ratio of omega-6 / omega-3 and arachidonic acid / docosahexaenoic acid in the group of children with ASD and epileptiform changes in the EEG. These results may support the theory of changes in the properties of the phospholipid membrane and ion channels of nerve cells and require further study using electron microscopy. The research was carried out in accordance with the principles of the Helsinki Declaration. The study protocol was approved by the Local Ethics Committee of all participating institutions. The informed consent of the patient was obtained for conducting the studies. No conflict of interests was declared by the authors. Keywords: autism spectrum disorders, epileptic seizures, essential fatty acids, monounsaturated fatty acids, unsaturated fatty acids, fatty acid unsaturation index.

Effects of dehydration speed on the metabolism of membrane lipids and its relation to the browning of the Thompson seedless grape

AbstractXinjiang is the main producing area of raisins and the largest green raisins production base in China. The browning of Thompson seedless grape raisin is extremely serious during the drying process, and has become the key issue in the development of Xinjiang raisin industry. Previous studies have shown that dehydration speed has a great impact on the browning of Thompson seedless grape, but few relevant mechanisms have been studied. Here, we demonstrate the effect of dehydration speed on lipid metabolism and its relation to the browning of the Thompson seedless grape during drying. Compared to slow dehydration treatment, rapid dehydration treatment of the Thompson seedless grape exhibited a lower degree of browning and activities of lipoxygenase (LOX), a higher index of unsaturated fatty acids and degree of unsaturated fatty acid. Moreover, the Thompson seedless grape treated with rapid dehydration resulted in a lower rate of superoxide anion production, hydrogen peroxide content, membrane permeability, and malondialdehyde content. These findings demonstrate that rapid dehydration inhibiting the browning of Thompson seedless grapes might be due to the inhibiting activities of LOX and the lower accumulation of reactive oxygen species. These activities can inhibit lipid peroxidation and slow the decomposition of unsaturated fatty acid in the membrane in Thompson seedless grapes, protecting the cellular membrane structural integrity, which may result in less contact of polyphenol oxidase with phenolic substrates and less enzymatic browning during drying. The results provide a theoretical basis for the application of rapid dehydration in drying Thompson seedless grapes.

Migrant blackbirds, Turdus merula, have higher plasma levels of polyunsaturated fatty acids compared to residents, but not enhanced fatty acid unsaturation index.

Birds have been observed to have dietary preferences for unsaturated fatty acids during migration. Polyunsaturated fatty acids (PUFAs) may increase the exercise performance of migrant birds; however, PUFAs are also peroxidation prone and might therefore incur increased costs in terms of enhanced oxidative damage in migratory individuals. To shed light on this potential constraint, we analyzed plasma fatty acid (FA) composition and estimated the unsaturation index as a proxy for susceptibility to lipid peroxidation of migrants and residents of the partially migratory common blackbird (Turdus merula) at a stopover site during autumn migration. As predicted, migrant birds had higher relative and absolute levels of PUFAs compared to resident birds. This included the strictly dietary ω‐3 PUFA α‐linolenic acid, suggesting a dietary and/or storage preference for these FAs in migrants. Interestingly, the FA unsaturation index did not differ between migrants and residents. These findings suggest a mechanism where birds alter their levels of metabolic substrate without simultaneously increasing the susceptibility of the substrate to lipid peroxidation. In summary, our results are in line with the hypothesis that increased exercise performance during migration might be constrained by oxidative stress, which is manifested in changes in the composition of key FAs to retain the unsaturation index constant despite the increased levels of peroxidizable PUFAs.

Influences of 1-methylcyclopropene-containing papers on the metabolisms of membrane lipids in Anxi persimmons during storage

Abstract Objectives The aim of this work was to analyse the effects of 1-methylcyclopropene (1-MCP) treatment on the metabolisms of membrane lipids in postharvest Anxi persimmons during storage. Materials and methods Anxi persimmon (Diospyros kaki L. f. cv. Anxi) fruits were treated by paper containing 1-MCP with a concentration of 1.35 μl/l. The cellular membrane permeability was analysed by the electric conductivity meter. The activities of lipoxygenase (LOX), phospholipase (PLD) and lipase were determined by spectrophotometry. The component and relative amounts of membrane fatty acids were determined using gas chromatograph (GC). Results The 1-MCP-treated Anxi persimmons manifested a lower electrolyte leakage rate, lower LOX, PLD and lipase activities, higher levels of unsaturated fatty acids (USFAs), higher ratio of USFAs to saturated fatty acids (SFAs) (U/S), higher index of USFAs (IUFA), but lower levels of SFAs. Conclusions The degradation and the metabolisms of membrane lipids could be suppressed by 1-MCP treatment, which might be accountable for the delaying softening of postharvest Anxi persimmons during storage.

Effects of Nitrate Enrichment on Respiration, Photosynthesis, and Fatty Acid Composition of Reef Coral Pocillopora damicornis Larvae

In the foreseeable future, coastal coral reef ecosystems are likely to face further increases in eutrophication. Lipids and fatty acids (FAs), as important components of corals, are becoming a hot topic to study the effects of eutrophication on corals. This study investigated the effects of nitrate (NO3-) enrichment (0, 5, 10, 20, and 40 μM) on the respiration, photosynthesis, and FA compositions of Pocillopora damicornis larvae. Our results showed that saturated fatty acids (SFAs) were the most abundant in P. damicornis larvae over all treatment groups, followed by polyunsaturated fatty acids (PUFAs). The unsaturated to saturated fatty acid ratio (U/S) and unsaturation index (UI) reduced at low nitrate concentrations (20 μM). The UI and U/S levels were elevated due to the increased PUFAs levels and decreased SFA levels at higher nitrate concentrations. Compared with the N5 and N10 groups, the fluidity of the biomembrane of the larvae did not continue to decrease but instead increased at higher nitrate concentrations, indicating that the biomembrane restructuring in the larvae may have become ineffective. Moreover, respiration increased and the consumption of numerous lipids led to a significant decrease in TFAs. These could adversely affect the dispersal, settlement, and development of larvae. Overall, P. damicornis larvae can adapt to low levels of nitrate (< 10 μM) due to biomembrane restructuring through changes in FA composition. However, negative effects occur in larvae when nitrate exceeds 20 μM.

Salicylic acid treatment suppresses Phomopsis longanae Chi-induced disease development of postharvest longan fruit by modulating membrane lipid metabolism

Salicylic acid (SA) is a crucial endogenous signaling molecule which can activate fruit defense responses to biotic or abiotic stress. The aim of this work was to study the effects of SA on disease occurrence, cell membrane integrity, membrane lipid-degrading enzymes activities, as well as amounts of cell membrane phospholipids and fatty acids in Phomopsis longanae Chi-inoculated longans during storage. The results indicated that, compared with the fruit with mere inoculation, SA treatment reduced fruit disease index and pericarp cell membrane permeability in P. longanae-inoculated longans. Additionally, SA treatment decreased activities of phospholipase D (PLD), phospholipase C (PLC), lipase, and lipoxygenase (LOX), lowered contents of saturated fatty acids (SFAs), phosphatidic acid (PA) and diacylglycerol (DAG), but suppressed the reductions of phosphatidylcholine (PC), phosphatidylinositol (PI), unsaturated fatty acids (USFAs), ratio of USFAs to SFAs (U/S), and index of unsaturated fatty acids (IUFA) in pericarp of P. longanae-inoculated longans. These data demonstrated that SA treatment could retain integrity of membrane structures, enhance fruit disease resistance to P. longanae, and thus suppress disease development in P. longanae-inoculated longans during storage. These results indicated that SA was an eco-friendly approach to inhibit disease development and extend storage-life of harvested longan fruit.

High CO2 alleviates cell ultrastructure damage in Autumn Royal table grapes by modulating fatty acid composition and membrane and cell oxidative status during long-term cold storage

Cell membranes provide a link between postharvest disorders and their integrity is essential for reducing table grape deterioration due to dehydration and susceptibility to fungal infection. We examined the relationship between ultrastructural membrane integrity at the subcellular level (transmission electron microscopy), cell (H2O2 generation) and membrane (malondialdehyde accumulation) oxidative status, membrane fatty acid composition (polar lipid fraction) and berry quality in order to determine the critical membrane events associated with long-term storage disorders at 0 °C in table grapes (Vitis vinifera L.) cv. Autumn Royal, and evaluate their response to the application of a single or dual short-term 20 kPa CO2 treatment. The results revealed a progressive disorganization of the cytoplasm and the breakdown of the cell organelle ultrastructure, associated with elevated hydrogen peroxide generation and lipid peroxidation rates and an imbalance in the saturated/unsaturated ratio of polar lipids, mainly due to the decrease in the degree of unsaturation of 18-carbon fatty acids. Conversely, high CO2 levels maintained the integrity of the microstructure of cell and energy-related organelles that are essential for metabolic damage repair and cell membrane restoration, reduced oxidative damage in cells and membranes, and increased the unsaturation of 18-carbon fatty acids, lipid unsaturation ratio and index of unsaturated fatty acids (IUFA) in the membrane polar lipids. The results also revealed that the more short-term high CO2 treatment is applied to Autumn Royal grapes, the more cytological evidence there is of enhanced tolerance to long-term cold and prevention of storage disorders in terms of cluster weight loss, rachis browning, berry water loss and decay incidence.

Hydrogen peroxide-induced changes in activities of membrane lipids-degrading enzymes and contents of membrane lipids composition in relation to pulp breakdown of longan fruit during storage

This study aimed to investigate the effect of hydrogen peroxide (H2O2) on membrane lipids metabolism and its relation to pulp breakdown development of longan fruit during postharvest storage. Compared to the control longans, H2O2-treated longans showed higher pulp breakdown index, cell membrane permeability, and activities of phospholipase D (PLD), lipase and lipoxygenase (LOX). Moreover, H2O2-treated longans maintained higher levels of pulp phosphatidic acid (PA) and saturated fatty acids (SFA). However, H2O2-treated longans exhibited lower levels of pulp phosphatidylcholine (PC), phosphatidylinositol (PI) and unsaturated fatty acids (USFA), lower index of unsaturated fatty acids (IUFA), and lower ratio of USFA to SFA (U/S). These findings demonstrated that H2O2 caused the increased activities of enzymes involving in membrane lipids degradation and the accelerated decompositions of membrane USFA and phospholipids in longan pulp, which eventually triggered the destruction of the pulp cell membrane structure and the development of pulp breakdown in longans during storage.

Overexpression of CCCH zinc finger protein gene delays flowering time and enhances salt tolerance in Arabidopsis by increasing fatty acid unsaturation

CCCH-type zinc-finger proteins constitute a large family playing key roles during plant development and growth. In the present study, we investigated the involvement of the CCCH-type zinc finger protein of AtZFP1 (At2g25900) in flowering and salt stress response in Arabidopsis. Compared with the wild type (WT), bolting and flowering were delayed in AtZFP1-overexpressing plants. Real-time PCR analysis of floral regulating genes in overexpressing Arabidopsis revealed that enhanced expression of FLC decreased the expressions of FT and SOC1. The Fv/Fm of overexpressing Arabidopsis lines was unchanged under salt stress. In contrast, ΦPSII activity and PSI oxidoreduction decreased in WT, overexpressing and mutant strains under salt stress conditions, with the smallest reduction in these parameters observed in the overexpressing strains. These results suggest that the CCCH zinc-finger protein AtZFP1 primarily controls flowering time by changing the expression of flowering genes under long-day conditions. The overexpression of this protein delayed flowering and increased the content and double-bond index of unsaturated fatty acids. Elevation of unsaturated fatty acid content might play important role in protecting the photosynthetic apparatus and maintaining the membrane function at salt stress by alleviating PSII and PSI photoinhibition.

Milk fatty acid variability and association with polymorphisms in SCD1 and DGAT1 genes in White Fulani and Borgou cattle breeds

The stearoyl-CoA desaturase 1 (SCD1) A293V and acyl CoA: diacylglycerol acyltransferase 1 (DGAT1) K232A polymorphisms have been associated with significant variation in bovine milk fatty acid composition and unsaturation indices in western cattle breeds. This study aimed to estimate the milk fatty acid variability in indigenous Borgou and White Fulani cattle breeds of Benin, and the effects of the SCD1 A293V and DGAT1 K232A polymorphisms on milk and fatty acid composition and unsaturation indices. Thus, 85 Borgou and 96 White Fulani cows were genotyped for the SCD1 A293V and DGAT1 K232A polymorphisms and their milk and fatty acid composition and unsaturation indices were determined. Borgou presented milk with higher linoleic acid (P < 0.001), oleic acid (P < 0.05), C18 index (P < 0.001), total unsaturation index (P < 0.05), and lower total saturated fatty acid (SFA) compared to White Fulani. The SCD1 VV genotype was associated with higher protein and lactose contents in White Fulani (P < 0.05). In Borgou, the SCD1 AV genotype was associated with higher C14 and total unsaturation indices (P < 0.01), while the SCD1 V allele was associated with decrease in C14 index (P < 0.05). In White Fulani, the SCD1 VV genotype was associated with lower C18:1 cis-9 content (P < 0.05) while the DGAT1 K allele was associated with increased total SFA (P < 0.05), and decreased C18 index (P < 0.05), total unsaturation index (P < 0.01) and total monounsaturated fatty acid (P < 0.01). The SCD1 A293V and DGAT1 K232A may serve as genetic markers to improve milk fatty acid traits in Borgou and White Fulani breeds.

Transcriptome analyses reveal genes and pathways associated with fatty acid composition traits in pigs.

Fatty acid composition is associated with meat quality in pigs as well as with obesity- and diabetes-related traits in humans. Liver and muscle are important tissues for fatty acid metabolism. In this study, we evaluated correlations between liver and muscle transcriptomes and fatty acid composition traits in muscle and abdominal fat tissues in 335 F2 pigs from a White Duroc×Erhualian F2 pig resource population. Transcripts significantly correlated with fatty acid composition traits were enriched for genes involved in the categories of triglyceride catabolic process, mitochondrial function, hematological and immune system, and disease such as Type II diabetes. Gene co-expression network analysis further identified liver network modules relevant to fatty acid unsaturation index that were enriched in platelet activation and the type I interferon signaling pathway and highlighted the connections between variations in fatty acid composition and genes involved in hematological and immune system. Integrative analysis of the expression QTL identified ELOVL6 and SCD as plausible candidate genes underlying the loci for muscle C18:1n-9/C16:1n-7 values on chromosome 8 and the loci for muscle C18:1n-9/C18:0 contents on chromosome 14 respectively.

Lasiodiplodia theobromae (Pat.) Griff. & Maubl.-induced disease development and pericarp browning of harvested longan fruit in association with membrane lipids metabolism

Effects of Lasiodiplodia theobromae inoculation on disease development, pericarp browning and membrane lipids metabolism of harvested “Fuyan” longan fruit were studied. Compared with control fruit, L. theobromae-inoculated longans showed higher fruit disease index, pericarp browning index and cell membrane permeability, as well as higher activities of phospholipase D, lipase and lipoxygenase. Additionally, there were lower contents of membrane phospholipids but higher content of phosphatidic acid, and lower level of unsaturated fatty acids but higher level of saturated ones with lower ratio of unsaturated fatty acid to saturated fatty acid and lower index of unsaturated fatty acids in pericarp of L. theobromae-inoculated longans. These results suggested that L. theobromae-induced disease development and pericarp browning of harvested longans might be attributed to the damaged cellular membrane structural integrity, induced by the activated membrane lipids-degrading enzymes increasing the degradation of membrane phospholipids and unsaturated fatty acids in pericarp of harvested longan fruit.

Molybdenum-induced alteration of fatty acids of thylakoid membranes contributed to low temperature tolerance in wheat

The fact that molybdenum (Mo) applications can alleviate low temperature stress (LTS) in plants has been widely reported, but the underlying mechanisms are not fully understood. The effects of Mo (0 and 0.15 mg kg−1) on photosynthetic pigments, fatty acids and the chlorophyll–protein complex of wheat seedlings in pot culture were investigated at 0, 2, 4 and 6 days of LTS. Chlorophyll a and b, total chlorophyll and carotenoid contents were significantly enhanced by Mo application. The palmitic acid (C16:0) content and total saturated fatty acids (TSFA) were drastically decreased in wheat cultivar 97003 at 2 and 4 days of LTS and in wheat cultivar 97014 at 2 days of LTS. The linolenic acid (C18:3) content and total unsaturated fatty acids (TUSFA) were significantly increased in both cultivars at 2 and 4 days of LTS. The palmitoleic acid (C16:1) content was also drastically increased in cultivar 97003 at 2 days of LTS, suggesting that Mo induced a greater production of unsaturated fatty acids or the conversion of TSFA to TUSFA. The ratio of unsaturated to saturated fatty acids and the index of unsaturated fatty acids in the thylakoid membranes were enhanced with supplemental Mo, suggesting that Mo might improve the degree of unsaturation. However, no significant differences were observed in the chlorophyll–protein complexes between the +Mo and −Mo treatments. These results indicated that the alteration of fatty acids induced by Mo application in the thylakoid membranes of wheat contributed to LTS tolerance.

Metabolism and secretion of yellow pigment under high glucose stress with Monascus ruber

The biosynthesis of microbial secondary metabolites is induced by a wide range of environmental stresses. In this study, submerged fermentation of Monascus yellow pigments by Monascus ruber CGMCC 10910 under high glucose stress was investigated. The increase of lipid content was the major contributor to the increase of dry cell weight (DCW), and the lipid-free DCW was only slightly changed under high glucose stress, which benefited the accumulation of intracellular hydrophobic pigments. The fatty acid composition analysis in Monascus cell membranes showed that high glucose stress significantly increased the ratio of unsaturated/saturated fatty acid and the index of unsaturated fatty acid (IUFA) value, which would improve the fluidity and permeability of the cell membrane. As a consequence, high glucose stress increased extracellular yellow pigments production by enhancing secretion and trans-membrane conversion of intracellular pigments to the broth. The total yield of extracellular and intracellular yellow pigments per unit of lipid-free DCW increased by 94.86 and 26.31% under high glucose stress compared to conventional fermentation, respectively. A real-time quantitative PCR analysis revealed that the expression of the pigment biosynthetic gene cluster was up-regulated under high glucose stress. The gene mppE, which is associated with yellow pigment biosynthesis, was significantly up-regulated. These results indicated that high glucose stress can shift the Monascus pigment biosynthesis pathway to accumulate yellow pigments and lead to a high yield of both extracellular and intracellular yellow pigments. These findings have potential application in commercial Monascus yellow pigment production.

Structural and functional characteristics of photosynthetic apparatus of chlorophyll-containing grape vine tissue

Photosynthesis in tissues under periderm of woody stems and shoots of perennial plants occurs in environment that is very different from the internal environment of leaf chloroplasts. These tissues are characterized by high CO2 and low O2 concentrations, more acidic surroundings, besides that only light which have passed through periderm reaches photosynthetic antennas. In contrast to leaves of deciduous plants chlorenchyma tissues of wintering plant organs are exposed to temperature fluctuations during all seasons, that is why the photosynthetic apparatus of woody stems has to be able to adapt to a wide range of environmental temperatures. In order to reveal unique features, which enable photosynthetic apparatus of chlorenchyma cells in woody plant organs to implement biological functions under different light and temperature conditions, we studied photosynthetic tissues of stem cortex in grapevine (Vitis vinifera L.) under normal conditions and after exposure to suboptimal temperatures and high light intensity. Comparative analysis of photosynthetic pigment composition and low-temperature chlorophyll fluorescence emission spectrum of leaves, young shoots and chlorenchyma of lignified shoots revealed relatively high level of chlorophyll b and carotenoids, and high photosystem II (PSII) to photosystem I (PSI) ratio in woody shoots. Analysis of parameters of variable chlorophyll fluorescence revealed high PSII activity in grapevine shoot cortex and demonstrated improved freeze tolerance and higher sensitivity to light of photosynthetic apparatus in grape vine in comparison to leaves. It was shown for the first time that photosynthetic apparatus in chlorenchyma cells of vine undergoes so-called “state-transition”–fast rearrangements leading to redistribution of energy between photosystems. Analysis of fatty acid (FA) compositions of lipids in examined tissues showed that the FA unsaturation index in green tissue of vine is lower than in leaves. A distinct feature of FA compositions of lipids in vine cortex was relatively high level of linoleic acid.

Calendula officinalis L. (Asteraceae) possess antioxidant properties on Fe2+-initiated peroxidation of rat brain microsomes

&lt;p class="ADMETabstracttext"&gt;In this study the effects of Calendula officinalis L. (Asteraceae) extract (CO) on the polyunsaturated fatty acid composition, chemiluminescence and unsaturation index of microsomes isolated from brain rat, are presented. After incubation of microsomes in an ascorbate (0.4 mM)-Fe&lt;sup&gt;2+&lt;/sup&gt; (2.15 µM) system (180 min at 37 °C) it was observed that the total cpm/mg protein originated from light emission:chemiluminescence was lower in brain microsomes obtained from CO group compared to the control group (without extract supplementation). Moreover, it was observed that the addition of the extract reduced chemiluminescence -measured as total cpm- in a concentration dependent manner. The fatty acid composition of brain microsomes from control group was profoundly modified when subjected to non-enzymatic lipoperoxidation with a considerable decrease of arachidonic acid C20:4w6 and docosahexaenoic acid C22:6w3. As a consequence, the unsaturation index, a parameter based on the maximal rate of oxidation of specific fatty acids, was higher in the CO group compared to controls. The simultaneous analysis of unsaturation index, chemiluminescence and fatty acid composition indicate that CO may act as an antioxidant protecting rat brain microsomes from peroxidative damage.&lt;/p&gt;