Exogenous ornithine is an effective precursor and the delta-ornithine amino transferase pathway contributes to proline accumulation under high N recycling in salt-stressed cashew leaves

The role of the delta-ornithine amino transferase (OAT) pathway in proline synthesis is still controversial and was assessed in leaves of cashew plants subjected to salinity. The activities of enzymes and the concentrations of metabolites involved in proline synthesis were examined in parallel with the capacity of exogenous ornithine and glutamate to induce proline accumulation. Proline accumulation was best correlated with OAT activity, which increased 4-fold and was paralleled by NADH oxidation coupled to the activities of OAT and Delta(1)-pyrroline-5-carboxylate reductase (P5CR), demonstrating the potential of proline synthesis via OAT/P5C. Overall, the activities of GS. GOGAT and aminating GDH remained practically unchanged under salinity. The activity of P5CR did not respond to NaCl whereas Delta(1)-pyrroline-5-carboxylate dehydrogenase was sharply repressed by salinity. We suggest that if the export of P5C from the mitochondria to the cytosol is possible, its subsequent conversion to proline by P5CR may be important. In a time-course experiment, proline accumulation was associated with disturbances in amino acid metabolism as indicated by large increases in the concentrations of ammonia, free amino acids, glutamine, arginine and ornithine. Conversely, glutamate concentrations increased moderately and only within the first 24 h. Exogenous feeding of ornithine as a precursor was very effective in inducing proline accumulation in intact plants and leaf discs, in which proline concentrations were several times higher than glutamate-fed or salt-treated plants. Our data suggest that proline accumulation might be a consequence of salt-induced increase in N recycling, resulting in increased levels of ornithine and other metabolites involved with proline synthesis and OAT activity. Under these metabolic circumstances the OAT pathway might contribute significantly to proline accumulation in salt-stressed cashew leaves. (C) 2011 Elsevier GmbH. All rights reserved.

Urinary acidifier in diet with high excess base for adult cats

Maintaining the pH of urine in the ideal range (6.2 - 6.4) is of great importance for health promotion in the lower urinary tract of cats. In the economic and standard feed sector this is a major concern, given that the animal urine tends to be alkaline after food consumption of those commercial segments, which predispose to the formation of struvite urolith. Therefore, this study aimed to study the effects of increasing levels of urinary acidifiers (0.0%, 0.3%, 0.6% and 0.9%, on a dry matter base) in feed with high excess base over the acid-basic balance in the organism, apparent digestibility coefficients of nutrients, urinary pH, hydro-electrolyte balance in cats, as well as the adequacy of equations proposed in the literature to estimate the urinary pH. Twenty-four adult cats, males and females were distributed in a completely randomized design, consisting of six animals per treatment. The dry matter content of urine presented a quadratic behavior (p<0,05; y = 9.5863 + 3.2299x + 0.7871x2 R2 = 99,91%), HCO3-, total CO2 and excess blood base during the period in which the animals were fed were high when including 0.9% acidifier compared to 0.6% (p<0.05). In contrast, the use of the additive did not change the urinary pH, blood electrolyte concentration, nutrient digestibility, fecal score, food and water intake (p>0.05). The equations proposed in the literature, which use excess of base in feed to estimate urinary pH, overestimated the pH values found in this study.

Consumer attitudes, knowledge, and behavior related to salt consumption in sentinel countries of the Americas

Objective. To describe individual attitudes, knowledge, and behavior regarding salt intake, its dietary sources, and current food-labeling practices related to salt and sodium in five sentinel countries of the Americas. Methods. A convenience sample of 1 992 adults (>= 18 years old) from Argentina, Canada, Chile, Costa Rica, and Ecuador (approximately 400 from each country) was obtained between September 2010 and February 2011. Data collection was conducted in shopping malls or major commercial areas using a questionnaire containing 33 questions. Descriptive estimates are presented for the total sample and stratified by country and sociodemographic characteristics of the studied population. Results. Almost 90% of participants associated excess intake of salt with the occurrence of adverse health conditions, more than 60% indicated they were trying to reduce their current intake of salt, and more than 30% believed reducing dietary salt to be of high importance. Only 26% of participants claimed to know the existence of a recommended maximum value of salt or sodium intake and 47% of them stated they knew the content of salt in food items. More than 80% of participants said that they would like food labeling to indicate high, medium, and low levels of salt or sodium and would like to see a clear warning label on packages of foods high in salt. Conclusions. Additional effort is required to increase consumers' knowledge about the existence of a maximum limit for intake and to improve their capacity to accurately monitor and reduce their personal salt consumption.

The effects of high-intensity resistance exercise on the blood lipid profile and liver function in hypercholesterolemic hamsters

It is well established that atherogenic dyslipidemia, characterized by high levels of triglycerides (TG), total cholesterol (TC), and low-density lipoprotein (LDL) cholesterol and low levels of high-density lipoprotein (HDL) cholesterol, constitutes important risk factors for cardiovascular disease. Regular exercise has been associated with a reduced risk for metabolic diseases. However, studies supporting the concept that resistance exercise is a modifier of blood lipid parameters are often contradictory. The aim of this study was to investigate the effects of high-intensity resistance exercise on the serum levels of TG, TC, HDL and non-HDL cholesterol, glucose, and the liver function enzymes alanine aminotransferase (ALT, EC 2.6.1.2) and aspartate aminotransferase (AST, EC 2.6.1.1) in golden Syrian hamsters (Mesocricetus auratus (Waterhouse, 1839)) fed a hypercholesterolemic diet. Sedentary groups (S) and exercise groups (E) were fed a standard diet (SS and ES) or a cholesterol-enriched diet (standard plus 1% cholesterol, SC and EC). Resistance exercise was performed by jumps in the water, carrying a load strapped to the chest, representing 10 maximum repetitions (10 RM, 30 s rest, five days per week for five weeks). Mean blood sample comparisons were made by ANOVA + Tukey or ANOVA + Kruskal-Wallis tests (p < 0.05) to compare parametric and nonparametric samples, respectively. There were no differences in blood lipids between the standard diet groups (SS and ES) (p > 0.05). However, the EC group increased the glucose, non-HDL, and TC levels in comparison with the ES group. Moreover, the EC group increased the TG levels versus the SC group (p < 0.05). In addition, the ALT levels were increased only by diet treatment. These findings indicated that high-intensity resistance exercise contributed to dyslipidemia in hamsters fed a hypercholesterolemic diet, whereas liver function enzymes did not differ in regards to the exercise protocol.

Structure and mechanism of diet specialisation: testing models of individual variation in resource use with sea otters

Studies of consumer-resource interactions suggest that individual diet specialisation is empirically widespread and theoretically important to the organisation and dynamics of populations and communities. We used weighted networks to analyze the resource use by sea otters, testing three alternative models for how individual diet specialisation may arise. As expected, individual specialisation was absent when otter density was low, but increased at high-otter density. A high-density emergence of nested resource-use networks was consistent with the model assuming individuals share preference ranks. However, a density-dependent emergence of a non-nested modular network for core resources was more consistent with the competitive refuge model. Individuals from different diet modules showed predictable variation in rank-order prey preferences and handling times of core resources, further supporting the competitive refuge model. Our findings support a hierarchical organisation of diet specialisation and suggest individual use of core and marginal resources may be driven by different selective pressures.