Physiological and metabolic adjustments of Hoplosternum littorale (Teleostei,Callichthyidae) during starvation

All animals face the possibility of limitations in food resources that could ultimately lead to mortality caused by starvation. The primary goal of this study was to characterize the various physiological strategies that allow fish to survive starvation. A multiparametric approach, including morphological biomarkers, blood plasma metabolites, oxidative stress and energy reserves, was used to assess starvation effects on the fish Hoplosternum littorale. Adult specimens were maintained at four experimental groups: control (fed ad libitum), and starved (not fed) fish for 7 and 28 days. Significant changes were observed not only after 28 days, but also after 7 days of starvation. In the shorter period, the hepatosomatic index as well as plasma triglycerides and glucose were significantly lower in starved fish than in the control ones. These results were accompanied by reduced lipid, glycogen and protein reserves in liver and diminished glycogen content in muscle, suggesting the need of these macromolecules as fuel sources. In addition, increased antioxidant enzyme activities were observed in gills, without evidence of oxidative stress in any of the evaluated tissues. Most significant differences were found in 28-days starved fish: total body weight together with the hepatosomatic index was lower when compared to control fish. The plasmatic metabolites tested (glucose, triglyceride, cholesterol and protein), all energy reserves in liver and glycogen content in muscle decreased in 28-days starved fish. Lipid oxidative damage was reported in liver, kidney and brain, and antioxidant enzymes (GST, GR, GPx and CAT) were activated in gills. According to the multivariate analysis, oxidative stress markers and metabolic parameters were key biomarkers that contributed in separating starved from fed fish. Our study allowed an integrated assessment of the fish response to this particular condition.     

Effect of thermal stress on metabolic and oxidative stress biomarkers of Hoplosternum littorale (Teleostei,Callichthyidae)

The present study aimed to investigate in Hoplosternum littorale (Hancock, 1828) the effects of different water temperatures (10 °C, 25 °C-control group- and 33 °C) on physiologic and metabolic traits following acute (1 day) and chronic (21 days) exposures. We analyzed several biomarker responses in order to achieve a comprehensive survey of fish physiology and metabolism under the effect of this natural stressor. We measured morphological indices, biochemical and hematological parameters as well as oxidative stress markers. To evaluate energy consumption, muscle and hepatic total lipid, protein and glycogen concentrations were also quantified. Extreme temperatures exposures clearly resulted in metabolic adjustments, being liver energy reserves and plasma metabolites the most sensitive parameters detecting those changes. We observed reduced hepatosomatic index after acute and chronic exposure to 33 °C while glycogen levels decreased at both temperatures and time of exposure tested. Additionally, acute and chronic exposures to 10 °C increased liver lipid content and plasma triglycerides. Total protein concentration was higher in liver and lower in plasma after chronic exposures to 10 °C and 33 °C. Acute exposition at both temperatures caused significant changes in antioxidant enzymes tested in the different tissues without oxidative damage to lipids. Antioxidant defenses in fish failed to protect them when they were exposed for 21 days to 10 °C, promoting higher lipid peroxidation in liver, kidney and gills. According to multivariate analysis, oxidative stress and metabolic biomarkers clearly differentiated fish exposed chronically to 10 °C. Taken together, these results demonstrated that cold exposure was more stressful for H. littorale than heat stress. However, this species could cope with variations in temperature, allowing physiological processes and biochemical reactions to proceed efficiently at different temperatures and times of exposure. Our study showed the ability of H. littorale to resist a wide range of environmental temperatures and contributes for the understanding of how this species is adapted to environments with highly variable physicochemical conditions.     

Hepatic antioxidant status and hematological parameters in rainbow trout,Oncorhynchus mykiss,after chronic exposure to carbamazepine

Recently, residual pharmaceuticals are generally recognized as relevant sources of aquatic environmental pollutants. However, the toxicological effects of these contaminants have not been adequately researched. In this study, the chronic toxic effect of carbamazepine (CBZ), an anticonvulsant drug commonly present in surface and ground water, on hepatic antioxidant status and hematological parameters of rainbow trout were investigated. Fish were exposed at sublethal concentrations of CBZ (1.0 μg/l, 0.2 mg/l and 2.0 mg/l) for 7, 21 and 42 days. Compared to the control group, fish exposed at higher concentration (0.2 mg/l or 2.0 mg/l) of CBZ showed significantly higher levels of hemoglobin, ammonia and glucose, and significantly higher plasma enzymes activities. During the exposure duration, erythrocyte count, hematocrit, mean erythrocyte hemoglobin, mean erythrocyte volume, mean color concentration and total protein content in all groups were not significantly different. At the highest test concentration (2.0 mg/l) of CBZ, oxidative stress was apparent as reflected by the significant higher lipid peroxidation and protein carbonyl levels in liver after 42 days exposure, associated with an inability to induce antioxidant enzymes activities including superoxide dismutase, glutathione peroxidase and glutathione reductase. After 42 days exposure, reduced glutathione level was significantly decreased in the fish exposed at 0.2 mg/l CBZ, compared with the control. In short, CBZ-induced physiological and biochemical responses in fish were reflected in the oxidant stress indices and hematological parameters. These results suggest that hepatic antioxidant responses and hematological parameter could be used as potential biomarkers for monitoring residual pharmaceuticals present in aquatic environment.     

Effects of exposure to sublethal propiconazole on intestine-related biochemical responses in rainbow trout,Oncorhynchus mykiss

The effect of long-term (30 days) exposure to PCZ (0.2, 50, and 500 μg l^?1) on intestine-related biochemical markers in rainbow trout was investigated. Multiple biomarkers were measured, including digestive enzymes (proteolytic enzymes and amylase), antioxidant responses (TBARS, CP, SOD, CAT, GR and GPx) and energy metabolic parameters (RNA/DNA ratio, Na⁺-K⁺-ATPase). Exposure to 500 μg l^?1 PCZ led to significantly inhibited (p < 0.01) proteolytic enzyme and amylase activity. Activities of the antioxidant enzymes SOD, CAT, and GPx gradually increased at lower PCZ concentrations (0.2 and 50 μg l^?1). At the highest concentration (500 μg l^?1), oxidative stress was apparent as significant higher (p < 0.05) lipid peroxidation and protein carbonyls, associated with an inhibition of antioxidant enzymes activity. Moreover, energy metabolic parameters (RNA/DNA ratio, Na⁺-K⁺-ATPase) were significantly inhibited (p < 0.01) in the intestines of fish exposed to 500 μg l^?1 PCZ, compared with controls. We suggest that long-term exposure to PCZ could result in several responses in intestine-related biochemical markers, which potentially could be used as indicators for monitoring residual PCZ present in the aquatic environment.     

The effects of dietary boric acid and borax supplementation on lipid peroxidation,antioxidant activity,and DNA damage in rats

The aims of this study were to clarify the effects of high dietary supplementation with boric acid and borax, called boron (B) compounds, on lipid peroxidation (LPO), antioxidant activity, some vitamin levels, and DNA damage in rats. Thirty Sprague Dawley male rats were divided into three equal groups: the animals in the first group (control) were fed with a standard rodent diet containing 6.4 mg B/kg, and the animals in the experimental group were fed with a standard rodent diet added with a supra-nutritional amount of boric acid and borax (100 mg B/kg) throughout the experimental period of 28 days. The B compounds decreased malondialdehyde (MDA), DNA damage, the protein carbonyl content (PCO) level in blood, and glutathione (GSH) concentration in the liver, Cu–Zn superoxide dismutase (SOD), and catalase (CAT) activity in the kidney. The B compounds increased GSH concentration in blood and the vitamin C level in plasma. Consequently, our results demonstrate that B supplementation (100 mg/kg) in diet decreases LPO, and enhances the antioxidant defense mechanism and vitamin status. There are no differences in oxidant/antioxidant balance and biochemical parameters except for serum vitamin A and liver GSH concentration, between the boron compounds used in this study.     

Comparative lipid peroxidation,antioxidant defense systems and proline content in roots of two rice cultivars differing in salt tolerance

The changes in the activity of antioxidant enzymes such as superoxide dismutase (SOD: EC 1.15.1.1), catalase (CAT: EC 1.11.1.6), peroxidase (POX: EC 1.11.1.7), ascorbate peroxidase (APOX: EC 1.11.1.11) and glutathione reductase (GR: EC 1.6.4.2), free proline content, and the rate of lipid peroxidation level in terms of malondialdehyde (MDA) in roots of two rice cultivars (cvs.) differing in salt tolerance were investigated. Plants were subjected to three salt treatments, 0, 60, and 120 mol m⁻³ NaCl for 7 days. The results showed that activated oxygen species may play a role in cellular toxicity of NaCl and indicated differences in activation of antioxidant defense systems between the two cvs. The roots of both cultivars showed a decrease in GR activity with increase in salinity. CAT and APOX activities increased with increasing salt stress in roots of salt-tolerant cultivar Pokkali but decreased and showed no change, respectively, in roots of IR-28 cultivar. POX activity decreased with increasing NaCl concentrations in salt-tolerant Pokkali but increased in IR-28. SOD activity showed no change in roots of both cultivars under increasing salinity. MDA level in the roots increased under salt stress in sensitive IR-28 but showed no change in Pokkali. IR-28 produced higher amount of proline under salt stress than in Pokkali. Increasing NaCl concentration caused a reduction in root fresh weight of Pokkali and root dry weight of IR-28. The results indicate that improved tolerance to salt stress in root tissues of rice plants may be accomplished by increased capacity of antioxidative system.     

Effect of gold nanoparticles on glutathione and malondialdehyde levels in liver,lung and heart of rats

We studied the effect of gold nanoparticles (NPs) on oxidative stress markers including reduced glutathione (GSH) and malondialdehyde (MDA) in different organs of rats. Adult male Wistar-Kyoto rats were randomly divided into 3 groups of 5 animals each. One group served as control and received vehicle only. The remaining two groups were treated with 50 μl of 10 nm sized gold NPs, daily for 3 and 7 days, respectively. The rats were sacrificed 24 h after the last injection of NPs. Administration of gold NPs did not cause any significant change in GSH levels in liver, lung and heart on day 3 or day 7. There was no significant effect of gold NPs on MDA levels in lung and heart whereas significant increases in MDA levels were found in the liver of rats treated with gold nanoparticles on both 3 and 7 days post-dosing (ANOVA F = 7.113, P = 0.010). In conclusion, the findings of this preliminary study suggest that gold NPs of 10 nm diameter produce significant lipid peroxidation in rat liver however lungs and heart do not show any oxidative stress. Further studies are warranted to examine the effects of a broader dose range of gold NPs on the levels of free radical indices in different organs of rats.     

Thermal acclimation in clownfish: An integrated biomarker response and multi-tissue experimental approach

The effects of increased temperature were tested in Amphiprion ocellaris, using a cellular diagnostics approach (in several tissues) combined with an organismal approach (body condition). Clownfish were exposed to a one month experiment following two temperature treatments: control (26 °C) and elevated temperature (30 °C). Fish were sampled at 0, 7, 14, 21 and 28 days for (1) assessment of stress biomarkers (catalase, lipid peroxidation, glutathione-S-transferase, superoxide dismutase, acetylcholinesterase, heat shock protein 70 kDa and ubiquitin – in brain, gills, liver, intestine and muscle), (2) estimation of integrated biomarker response index based on the biomarkers tested and (3) assessment of Fulton’s K index. Results show all biomarkers except acetylcholinesterase responded consistently and significantly to elevated temperature across tissue types suggesting they are suitable indicators of thermal stress in A. ocellaris. Biomarker levels were tissue-specific, and in addition, the most reactive tissues to temperature were muscle, gills and liver which suggest that highly oxygenated tissues seem to be the most responsive under thermal stress. The most responsive sampling times to increased temperature were T7 and T28: thermal stress was observed after 7 days of exposure (biomarker levels increased), then a pattern of decrease in biomarker levels towards the end of the experiment was observed, which may suggest fish were able to acclimate to exposure conditions. This indicates that A. ocellaris probably lives far from its upper thermal limit and is capable of adjusting the protein quality control system and enzymes’ activities to protect cell functions under elevated temperatures. The temperature treatment did not significantly influence body condition of the animals but biomarkers were negatively correlated to wet body weight. This suggests that thermal acclimation incurs at some energetic cost. In conclusion, these results suggest that this coral reef fish species presents a significant acclimation potential under ocean warming scenarios of +4 °C.     

Short term exposure of pendimethalin induces biochemical and histological perturbations in liver,kidney and gill of freshwater fish

Our study was designed to evaluate effects of an herbicide, pendimethalin on biochemical biomarkers and histopathological indices of the freshwater fish Channa punctata Bloch. Fish were acutely exposed (96 h) to sub-lethal concentrations (0.5 and 0.8 ppb of pendimethalin). Various oxidative stress indicators such as thiobarbituric acid reactive substances levels and protein carbonyl content, as well as antioxidant defenses parameters, such as glutathione-S-transferase (GST), catalase (CAT), reduced glutathione (GSH) and non-protein thiols (NP-SH) levels were studied, using the liver, kidney and gill tissues. Pendimethalin exposure increased lipid peroxidation and protein oxidation processes. There was significant inhibition in levels of GSH and NP-SH. The activity of antioxidant enzymes GST and CAT depleted in all the tissues in a dose dependent manner. The histopathological change in the gill showed necrosis and atrophy of primary and secondary gill lamellae. The tissue damages like degeneration of cytoplasm in hepatocytes, atrophy, formation of vacuoles, are some histopathological changes observed in the liver. The changes in histoarchitechture observed in the kidney included necrosis, cellular hypertrophy and granular cytoplasm. The present study demonstrates the disturbances in antioxidant armamentarium and importance of study in the potential risk assessment of herbicides on fish species.     

The effect of glucose and maltose concentrations on pyruvate and ascorbate production,antioxidant enzyme activities and LPO levels in Fusarium equiseti

Changes in pyruvate and ascorbate production and antioxidant enzyme activities together with lipid peroxidation levels in Fusarium equiseti were investigated in relation to changes in the concentrations of glucose and maltose as carbon sources in the range of 5–25 g/l in Armstrong Fusarium Medium (AFM). The highest pyruvate concentration obtained at 20 g/l maltose was 67.5 ± 0.69 μg/ml while ascorbic acid reached a maximum value at 25 g/l glucose of 1866±26.1 μg/ml The maximum superoxide dismutas (SOD) activities related to increased pyruvate production were determined in AFM medium containing 20 g/l glucose as 41.49±0.65 and maltose as 61.12±0.8 IU/mg. Catalase (CAT) activity variations showed coherence with SOD activity in a medium containing maltose and reached 219.11±2.8 IU/mg while they were decreased with increasing glucose concentration. glutathione peroxidase (GSH-Px) activities in F. equiseti did not change significantly with glucose and maltose concentration and were determined to be 1.21±0.22 and 1.67±0.15 IU/mg, respectively. Minimum lipid peroxidation levels for each carbon source were determined in both 20 g/l maltose and glucose concentrations as 0.9 and 1.62 nmol MDA/g wet weight.     

The protective effect of montelukast sodium on carbon tetrachloride induced hepatopathy in rat

AimThis study investigates the effects of montelukast sodium (MK) (CysLTLT1 receptor antagonist) on CCl₄induced hepatopathy on rat.Material and methodsWe worked on 4 groups of 10 Wistar male rats each. The groups received as follows: group I (control group) – saline, group II – MK 5 mg/kg/day i.p. for 5 days, group III – MK 5 mg/kg/day i.p., 1 day prior to and 4 days concomitantly with CCl₄ p.o., 0.3 ml/Kg/day and group IV – CCl₄, p.o., 0.3 ml/Kg/day for 4 days. One day after the last administration, samples of blood were taken and alanine aminotransferase (ALT), total bilirubin (TB), direct bilirubin (DB), malondialdehyde (MDA), catalase (CAT) as well as total antioxidant capacity (TAC) were determined. The histopathological exam was performed. We also determined superoxide dismutase (SOD), MDA, CAT and GSH in liver homogenate.ResultsCompared to group IV, group III exhibited statistically significant lower levels of ALT (318 ± 15.75 versus 203.14 ± 10.28 UI, p < 0.0001), TB (3.16 ± 0.30 versus 1.99 ± 0.08 mg/dl, p < 0.0001), MDA in blood and in liver homogenate (4.98 ± 1.71 versus 2.15 ± 1.18 nmol/ml, p = 0.0004) and higher levels of SOD and CAT. Histopathologically, group IV presented important macro- and micro-vesicular hepatic steatosis and group III preserved lobular histoarchitecture and had less severe cellular lesions.ConclusionMK exhibits a partial hepatoprotective effect on rats treated with CCl₄.     

Alterations in the general condition,biochemical parameters and locomotor activity in Cnesterodon decemmaculatus exposed to commercial formulations of chlorpyrifos,glyphosate and their mixtures

The Pampean region, an extensive area of South America is continuously impacted by agricultural activities and the pesticides related to them like chlorpyrifos and glyphosate. Both pesticides have been registered in freshwater bodies of the region. One of the most abundant and widely distributed fish species in Pampean streams is Cnesterodon decemmaculatus, which have to cope with this altered scenario.In the present study the toxicity of Clorfox^® and Roundup Max^®, the commercial formulations of chlorpyrifos and glyphosate, respectively, and their mixture where evaluated using a set of biomarkers at different biological organization levels in fish exposed to relevant environmentally pesticides concentrations. Somatic indexes such as the condition factor (K), and the hepato-somatic index (HSI), the locomotor activity through the distance traveled and the average speed, the enzymatic activities of acetylcholinesterase (AChE) in brain and muscle, catalase (CAT) in muscle and liver, glutathione-S-transferase (GST) in brain, liver, muscle and gills, aspartate amino-transferase (AST), alanine amino-transferase (ALT), AST/ALT ratio and alkaline phosphatase (ALP) in liver were measured on C. decemmaculatus. Adult females were exposed during 6 weeks to the following concentrations: 0.0084 μl/l and 0.00084 μl/l of Clorfox (CF), 0.2 and 2 mg/l of Roundup Max (RM) and all the combinations of these concentrations. The CF exposure caused a decrease in the condition factor and in the locomotor activity parameters and induced an increase brain AChE, liver CAT activity and AST/ALT ratio. On the other hand, the exposure to RM produced a decrease in liver GST, AST/ALT ratio and ALP activity. Finally, some pesticide combinations decrease general condition and liver GST activities, and increase brain GST and liver ALP activities. Different responses in biomarkers were observed in mixtures treatments, reflecting the complex interactions between these toxics and suggesting a suppressive action of RM on CF effects.Since the concentrations we tested are environmentally relevant and the overall fish health condition was affected, the presence of these pesticides in freshwater systems could impose a risk for populations by causing deleterious effects on C. decemmaculatus in Pampean region.     

In vitro alpha-amylase inhibition and in vivo antioxidant potential of Momordica dioica seeds in streptozotocin-induced oxidative stress in diabetic rats

Momordica dioica Roxb. Commonly known as “Kakora” in Telugu, is used in the Indian traditional system of medicine for the treatment of diabetes. The aim of this study was to investigate the antidiabetic activity of methanolic extract of M. dioica seeds (MEMD) in streptozotocin (STZ) induced diabetic rats. The in vitro α-amylase inhibitory activity of the MEMD was done by spectrophotometric method. Diabetes was induced by STZ (45 mg/kg; i.p), MEMD (100 & 200 mg/kg; b.wt) and standard drug metformin (50 mg/kg; b.wt) were administered to the diabetic rats. Blood glucose was estimated on the 11th day and the level of MDA, SOD and CAT was estimated in the liver tissue homogenate after the 15 days of experimental period. MEMD showed significant inhibition of alpha amylase activity and the IC₅₀ was found to be 48 μg/ml. Oral administration of MEMD significantly reduced blood glucose level (P < 0.05), diminished the MDA level and refurbished depleted antioxidant enzymes and Insulin level to normalcy. These findings revealed that M. dioica seeds possess antihyperglycemic, antioxidant and anti lipid peroxidative activity and thus mitigate STZ-induced oxidative damage.     

Effect of Zinc nanoparticles on oxidative stress-related genes and antioxidant enzymes activity in the brain of Oreochromis niloticus and Tilapia zillii

This study was carried out to determine the median lethal concentrations (LC₅₀) of Zinc nanoparticles (ZnNPs) on Oreochromis niloticus and Tilapia zillii. The biochemical and molecular potential effects of ZnNPs (500 and 2000 μg L⁻¹) on the antioxidant system in the brain tissue of O. niloticus and T. zillii were investigated. Four hundred fish were used for acute and sub-acute studies. ZnNP LC₅₀ concentrations were investigated in O. niloticus and T. zillii. The effect of 500 and 2000 μg L⁻¹ ZnNPs on brain antioxidants of O. niloticus and T. zillii was investigated. The result indicated that 69 h LC₅₀ was 5.5 ± 0.6 and 5.6 ± 0.4 for O. nilotica and T. zillii, respectively. Fish exposed to 500 μg L⁻¹ ZnNPs showed a significant increase in reduced glutathione (GSH), total glutathione (tGSH) levels, superoxide dismutase (SOD), catalase (CAT), glutathione reductase (GR), glutathione peroxidase (GPx) and glutathione-S-transferase (GST) activity and gene expression. On the contrary, malondialdehyde (MDA) levels significantly decreased. Meanwhile, fish exposed to 2000 μg L⁻¹ ZnNPs showed a significant decrease of GSH, tGSH levels, SOD, CAT, GR, GPx and GST activity and gene expression. On the contrary, MDA levels significantly increased. It was concluded that, the 96 h LC₅₀ of ZnNPs was 5.5 ± 0.6 and 5.6 ± 0.4 for O. nilotica and T. zillii, respectively. ZnNPs in exposure concentrations of 2000 μg/L induced a deleterious effect on the brain antioxidant system of O. nilotica and T. zillii. In contrast, ZnNPs in exposure concentrations of 500 μg L⁻¹ produced an inductive effect on the brain antioxidant system of O. nilotica and T. zillii.     

Temperature modulates hepatic carbohydrate metabolic enzyme activity and gene expression in juvenile GIFT tilapia (Oreochromis niloticus) fed a carbohydrate-enriched diet

The effects of rearing temperature on hepatic glucokinase (GK), glucose-6-phosphatase (G6Pase) and Glucose-6-phosphate dehydrogenase (G6PD) activity and gene expression were studied in GIFT (genetically improved farmed tilapia) tilapia fed a high carbohydrate diet containing 28% crude protein, 5% crude lipid and 40% wheat starch. Triplicate groups of fish (11.28 g initial body weight) were fed the diet for 45 days at 22 °C, 28 °C or 34 °C. At the end of the trial, final body weight of juvenile at 28 °C (59.12 g) was higher than that of the fish reared at 22 °C (27.13 g) and 34 °C (43.17 g). Feed intake, feed efficiency and protein efficiency ratio were also better at 28 °C. Liver glycogen levels were higher at 28 °C, while plasma glucose levels were higher in the 22 °C group. Significant (P<0.05) effects of water temperature on enzymes activities and gene expression were observed. Hepatic GK activity and mRNA level were higher at 28 °C than at 34 °C. Higher G6Pase and G6PD activity and gene expression were observed at 22 °C. Overall, the data show that juveniles reared at 28 °C exhibited enhanced liver glycolytic capacity. In contrast, hepatic gluconeogenesis and lipogenesis were increased by low temperature (22 °C).     

Copper/zinc and copper/selenium ratios,and oxidative stress as biochemical markers in recurrent aphthous stomatitis

ProjectRecurrent aphthous stomatitis (RAS) is a common oral mucosal disorder characterized by recurrent, painful oral aphthae, and oxidative stress presumably contributes to its pathogenesis. The aim of this study is to scrutinize the relationship between oxidative stress and serum trace elements (copper, Cu; zinc, Zn; selenium, Se), and to evaluate the ratios of Cu/Zn and Cu/Se in this disorder.ProcedurePatients with RAS (n = 33) and age- and sex-matched healthy control subjects (n = 30) were enrolled in this study. Malondialdehyde (MDA) concentrations in plasma and the activities of superoxide dismutase (SOD1; CuZnSOD), glutathione peroxidase (GPx) and catalase (CAT) in erythrocyte were determined as spectrophotometric. Also, the levels of Se, Zn and Cu in serum were determined on flame and furnace atomic absorption spectrophotometer using Zeeman background correction.Results and conclusionsOxidative stress was confirmed by the significant elevation in plasma MDA, and by the significant decrease in CAT, SOD1, and GPx (p < 0.05). When compared to controls, Zn and Se levels were significantly lower in patients, whereas Cu levels was higher in RAS patients than those in controls (p < 0.05). In addition, the correlation results of this study were firstly shown that there were significant and positive correlations between Se–CAT, Se–GPx, and Cu–MDA parameters, but negative correlations between Se–Cu, Se–MDA, Cu–CAT, Cu–SOD1 and Cu–GPx parameters in RAS patients. Furthermore, the ratios of Cu/Zn and Cu/Se were significantly higher in the patients than the control subjects (p < 0.05). Our results indicated that lipid peroxidation associated with the imbalance of the trace elements seems to play a crucial role in the pathogenesis of RAS. Furthermore, the serum Cu/Zn and Cu/Se ratios may be used as biochemical markers in these patients.     

Effect of fasting on body composition and responses to stress in sunshine bass

The integrated responses of the hormonal regulation of growth and stress in sunshine bass (Morone chrysops X Morone saxatilis) as regulated by feed deprivation were investigated. Groups of fish were fed 1.5% of the body weight per day or offered no feed for 4 weeks. Another group of fish was not fed for 3 weeks and feed was offered during the fourth week. Fish in each group were sampled immediately before or after a 15-min low water confinement stressor after each week of the experiment. Liver mass and liver glycogen content were decreased after one week of fasting and remained low until the end of the study. However, both recovered after a week of refeeding. Intraperitoneal fat was significantly lower after two weeks of fasting and did not recover after a week of refeeding. None of these components were affected by confinement stress. Plasma glucose in unstressed fish was generally unaffected by fasting or refeeding; however, plasma glucose increased after confinement stress in fed but not in fasted fish. The cortisol stress response was unaltered by fasting and remained robust. Plasma IGF-I generally decreased in fasted fish but was not significantly lower than fed fish until the fourth week. A week of refeeding did not restore plasma IGF-I concentrations. Plasma IGF-I concentrations were higher in confinement stressed fed fish after two and four weeks but were unchanged in the fourth week. There was no change in the plasma IGF-I concentrations in fasted or refed fish due to the stress. Liver weight and liver glycogen were essentially depleted after 2 weeks of fasting. The reduction of liver glycogen greatly reduced the glucose response to stress; however, the cortisol stress response was maintained for at least four weeks of fasting. Intraperitoneal fat was decreased very little after 4 weeks of fasting. Plasma IGF-I concentrations were reduced only after 3 weeks of fasting.     

Hypolipidemic effect of Goami-3 rice (Oryza sativa L. cv. Goami-3) on C57BL/6J mice is mediated by the regulation of peroxisome proliferator-activated receptor-α and -γ

We investigated the hypolipidemic effects of Goami-3 rice (GR; Oryza sativa L. cv. Goami-3), a newly developed strain with high levels of amylose and fibers. Diet-induced obese mice were fed three types of isocaloric diets for 8 weeks: a high-fat diet, a high-fat diet with GR or control rice (CR; O. sativa L. cv. Ilpumbyeo). Mice fed GR exhibited a significant reduction in body fat (–23%), total cholesterol (–20%) and triglyceride concentrations (–30%) compared to mice fed CR. The mice fed GR showed induction of peroxisome proliferator-activated receptor (PPAR)-α and inhibition of γ expressions in the liver and adipose tissue. The reduced adiposity of mice fed GC was supported by changes in the expression of genes related to lipid accumulation and hydrolysis in adipose tissues and the plasma concentrations of insulin, adiponectin and leptin. Principal components analysis with gas chromatography–time-of-flight mass spectrometry-based metabolomic data revealed that the average level of specific plasma metabolites in the GR group was statistically different from that in the other groups after 4 weeks. These metabolites included propionic acid, valine, leucine and proline. Based on partial least-squares analysis, the plasma concentrations of valine were inversely correlated with the high-density lipoprotein (HDL) to non-HDL and HDL to total cholesterol ratios. In conclusion, GR feeding for 8 weeks significantly improved dyslipidemia and adiposity in diet-induced obese mice by regulating gene expression of PPARs and its target genes. Key plasma metabolites (including valine) were significantly altered by the hypolipidemic effects of GR.     

Does salt stress increase the ability of the exotic legume Acacia longifolia to compete with native legumes in sand dune ecosystems?

Sand dune ecosystems are one of the areas most affected by the introduction of invasive species which represents a threat for biodiversity conservation. Their invasion patterns and spread may depend on their salinity tolerance, besides other factors. To test this hypothesis, we investigated the effects of salt stress on seed germination and on the activity of antioxidant enzymes (catalase, CAT; ascorbate peroxidase, APX; peroxidase, POX; and glutathione reductase, GR) in two legume species, an invasive, Acacia longifolia (Andrews.) Willd., and a native, Ulex europaeus (L.), very common in the sand dunes of the coast of Portugal. Salt stress was induced by adding NaCl at different concentrations, 0, 50, 100 and 200 mM, for 15 days. Results showed that the highest germination percentages were obtained in distilled water (control) and that, with increasing salt concentration, seed germination was delayed and decreased in both species. Inhibition of germination was higher in the native species, only 3% of seeds germinated at 100 mM and no seeds germinated at 200 mM NaCl. In the invasive species, the reduction was higher at 200 mM NaCl (16%). Considering the coefficient of germination velocity, a decrease in both species with increasing NaCl concentration was observed. The CAT and GR activities decreased in A. longifolia with increasing salinity. In turn, APX activity significantly increased as NaCl concentration increased while the POX activities declined at the highest NaCl concentration. On the other hand, at 50 mM NaCl lower activity of CAT and APX and higher GR and POX were found in U. europaeus. In both species, protein content increased as NaCl concentration increased. In addition, it seems that APX activities play an essential role in the scavenging reactive oxygen species (ROS). These results suggest that the seeds of the invasive legume A. longifolia are more tolerant to salinity than the native legume U. europaeus, and seem better equipped to handle the physiological stress of high salinity, which may contribute to its invasive ability in sand dunes.