Effects of Various Number of Applications and Treatment of Growth Retardants on Leaf Formation, Bolting, and Yield of Leaf and Cos Lettuce (Lactuca Sativa L.)

Horticultur

Enzymatic and non-enzymatic link components of antioxidant defence in subcellular fractions of rat liver under the influence of diethyl phthalate

Background. The antioxidant system is one of the protective cell systems. Changes in its functioning, after the introduction of xenobiotics into the body, will determine the further course of the intensity of free radical processes. Among xenobiotics, a prominent place belongs to phthalates, in particular diethyl phthalate (DEP) – the most common group of synthetic substances that are widely used as plasticizers in various industries. Materials and Methods. For a series of experiments, white outbred rats were used, and cytosolic and microsomal fractions were isolated from the liver cells. The activity of such antioxidant enzymes as superoxide dismutase (SOD, EC 1.15.1.1), catalase (CAT, EC 1.11.1.6), glutathione peroxidase (GSH-Px, EC 1.11.1.9), glutathione S-transferase (GST, EC 2.5.1.18), and the concentration of reduced glutathione (GSH) were determined in the cytosolic fraction. GST activity was also studied in the microsomal fraction. Results and Discussion. The administration of different doses of DEP for 14 days promoted the activation of antioxidant enzymes, regardless of the dose of xenobiotic administration. The use of DEP for 21 days led to a multidirectional effect of the xenobiotic on the enzymes of the antioxidant system in liver cells. The inactivation of the studied enzymes and depletion of the GSH pool were observed when DEP was administered at a dose of 5.4 mg/kg of body weight. The activity of antioxidant enzymes in liver subcellular fractions remained at a high level compared to the control when DEP was administered at a dose of 2.5 mg/kg of body weight. It was established that the same trend of changes in GST enzyme activity was found in both the microsomal and cytosolic fractions of rat liver. The activity of the enzyme increased under the influence of both studied doses under the administration of DEP for 14 days. Administration of the xenobiotic for 21 days led to a decrease in GST activity when a high dose of DEP was administered. Conclusion. The activation of antioxidant system enzymes occurs in response to a short-term intake of DEP. With an increase in the dose and duration of administration of the studied xenobiotic, inactivation of antioxidant enzymes was detected

Oxidation process intensity in microsomal fraction of rat liver under conditions of different supplementation with polyunsaturated fatty acids

The effect of fat compositions with the varying ratio of polyunsaturated fatty acids (PUFAs) of families ω-3 and ω-6 on oxidation process intensity in microsomal fraction of rat liver has been investigated. The aim of the study was to investigate the level of markers of oxidative modification of lipids and proteins in microsomal fraction of rat liver. Fat components in the experiment diets were presented by sunflower oil, soybean oil and fish oil. Rats were fed using one of the fillowing 5 diets for the period of 4 weeks: 1) AIN-93 diet with 7% sunflower oil and fish oil, with the inclusion of linoleic acid, eicosapentaenoic acid and docosahexaenoic acid in the ratio of ω-6:ω-3 – 7:1 (control diet); 2) AIN-93 diet with 7% soybean oil, with the inclusion of linoleic acid and α-linolenic acid in the ratio of 7:1; 3) the diet containing only ω-6 PUFAs; 4) the diet containing only ω-3 PUFAs; 5) the diet without PUFAs. The fatty acid compositions of the diets were analysed by gas chromatography. We measured the primary and secondary lipoperoxidation products, proteins carbonyl derivatives and SH-groups of proteins. It was shown that inclusion of linoleic acid and α-linolenic acid in the ratio of 7:1 or ω-6 PUFAs into the animal diet increased lipid peroxidation in microsomal fraction of the rat liver as compared with the control group. Only ω-6 PUFAs increased the oxidative modification of proteins in microsomal fraction of the rat liver as compared with the control rat group. High dose of ω-3 PUFAs – eicosapentaenoic acid and docosahexaenoic acid had no influence on free radical oxidation of lipids and proteins. Using the diet without PUFAs increased oxidation process intensity in microsomal fraction of rat liver. According to our study, ω-6 PUFAs increased the oxidative modification of lipids and proteins in microsomal fraction of the rat liver. ω-3 PUFAs, in particular, eicosapentaenoic acid and docosahexaenoic acid, increased lipid and protein resistance to oxidative modification in microsomal fraction of the rat liver

Effect of precooling and ethylene absorbent on the quality of Dendrobium "Pompadour" flowers

We studied the effect of precooling and the use of an ethylene absorbent (based on potassium permanganate) in the flower boxes, on the vase life of Dendrobium `Pompadour` flowers, after simulation of air shipment (3 days at 25°C). Precooling at 10°C (85-95%RH) for 60 minutes reduced ethylene production, ACC activity, and the concentration of 1-aminocyclopropane-1-carboxylic acid (ACC) in the flowers, during shipment. Precooling for 90 minutes or longer did not have a positive effect on the chilling-sensitive Dendrobium flowers. The presence of an ethylene absorbent in the cardboard boxes further reduced ethylene concentration in the boxes. The combination of 60 min precooling and the ethylene absorbent was optimal to reduce epinasty of the buds and flowers, to promote bud opening and to prevent abscission of open flowers. It also considerably delayed the time to in visible petal withering

Proteins oxidative modification and antioxidant enzymes activity in the liver mitochondria of rats under laser irradiation and administration of ω-3 polyunsaturated fatty acids

The effect of laser irradiation of rats combined with omega-3 polyunsaturated fatty acids (ω-3 PUFA) administration on the proteins oxidative modification and superoxide dismutase and catalase activity in the mitochondrial fraction of the liver was investigated. Animals were irradiated with a 650 nm laser diode in the abdomen daily for 4 min at the distance of 10 cm from the skin surface. ω-3 PUFA were administered per os at a daily dose of 120 mg/kg of the body weight. Fatty acids in the fish oil were identified by gas chromatography. Animals were divided into five groups (12 animals in each group): I – intact rats (control); II – rats exposed to the daily laser irradiation for 7 or 14 days ; III – rats that received ω-3 PUFA two hours after irradiation; IV – rats that received ω-3 PUFA two hours before irradiation; V – rats that received ω-3 PUFA for 7 days before irradiation. The mitochondrial fraction of rat liver was obtained by differential centrifugation. The increase in the content of protein carbonyl derivatives and a decrease of protein thiol groups in the liver mitochondrial fraction were detected after seven-day laser irradiation of rats. As the duration of irradiation increases, superoxide dismutase and catalase activity was decreased, indicating a depletion of mitochondrial antioxidant reserves. No antioxidant effect was observed when ω-3 PUFA were administrated after laser irradiation and a slight antioxidant effect was shown when ω-3 PUFA were administrated two hours before irradiation. Preliminary seven-day administration ω-3 PUFA before laser irradiation was the most effective, as it reduced the level of protein carbonyl derivatives and O2•--generation, increased proteins SH-groups content and antioxidant enzymes activity

Metabolic effects of elevated temperature on organic acid degradation in ripening <em>Vitis vinifera</em> fruit

First published online: September 1, 2014Berries of the cultivated grapevine Vitis vinifera are notably responsive to temperature, which can influence fruit quality and hence the future compatibility of varieties with their current growing regions. Organic acids represent a key component of fruit organoleptic quality and their content is significantly influenced by temperature. The objectives of this study were to (i) manipulate thermal regimes to realistically capture warming-driven reduction of malate content in Shiraz berries, and (ii) investigate the mechanisms behind temperature-sensitive malate loss and the potential downstream effects on berry metabolism. In the field we compared untreated controls at ambient temperature with longer and milder warming (2-4 °C differential for three weeks; Experiment 1) or shorter and more severe warming (4-6 °C differential for 11 days; Experiment 2). We complemented field trials with control (25/15 °C) and elevated (35/20 °C) day/night temperature controlled-environment trials using potted vines (Experiment 3). Elevating maximum temperatures (4-10 °C above controls) during pre-véraison stages led to higher malate content, particularly with warmer nights. Heating at véraison and ripening stages reduced malate content, consistent with effects typically seen in warm vintages. However, when minimum temperatures were also raised by 4-6 °C, malate content was not reduced, suggesting that the regulation of malate metabolism differs during the day and night. Increased NAD-dependent malic enzyme activity and decreased phosphoenolpyruvate carboxylase and pyruvate kinase activities, as well as the accumulation of various amino acids and γ-aminobutyric acid, suggest enhanced anaplerotic capacity of the TCA cycle and a need for coping with decreased cytosolic pH in heated fruit.C. Sweetman, V. O. Sadras, R. D. Hancock, K. L. Soole and C. M. For