Effects of salinity and drought on growth, ionic relations, compatible solutes and activation of antioxidant systems in oleander (Nerium oleander L.)

[EN] Nerium oleander is an ornamental species of high aesthetic value, grown in arid and semi- arid regions because of its drought tolerance, which is also considered as relatively resistant to salt; yet the biochemical and molecular mechanisms underlying oleander¿s stress toler- ance remain largely unknown. To investigate these mechanisms, one-year-old oleander seedlings were exposed to 15 and 30 days of treatment with increasing salt concentratio ns, up to 800 mM NaCl, and to complete withholding of irrigation; growth parameters and bio- chemical markers characteristic of conserved stress-response pathways were then deter- mined in stressed and control plants. Strong water deficit and salt stress both caused inhibition of growth, degradation of photosynthetic pigments, a slight (but statistically signifi- cant) increase in the leaf levels of specific osmolytes, and induction of oxidative stress¿as indicated by the accumulation of malondialdehyde (MDA), a reliable oxidative stress marker ¿accompanied by increases in the levels of total phenolic compounds and antioxidant fla- vonoids and in the specific activities of ascorbate peroxidase (APX) and glutathione reduc- tase (GR). High salinity, in addition, induced accumulation of Na + and Cl - in roots and leaves and the activation of superoxide dismutase (SOD) and catalase (CAT) activities. Apart from anatomical adaptations that protect oleander from leaf dehydration at moderate levels of stress, our results indicate that tolerance of this species to salinity and water deficit is based on the constitutive accumulation in leaves of high concentratio ns of soluble carbohydrates and, to a lesser extent, of glycine betaine, and in the activation of the aforementioned antiox- idant systems. Moreover, regarding specifically salt stress, mechanisms efficiently blocking transport of toxic ions from the roots to the aerial parts of the plant appear to contribute to a large extent to tolerance in Nerium oleanderThis work was financed by internal funds of the Polytechnic University of Valencia to Monica Boscaiu and Oscar Vicente. Dinesh Kumar’s stay in Valencia was financed by a NAMASTE fellowship from the European Union, and Mohamad Al Hassan was a recipient of an Erasmus Mundus pre-doctoral scholarship financed by the European Commission (Welcome Consortium).Kumar, D.; Al Hassan, M.; Naranjo Olivero, MA.; Agrawal, V.; Boscaiu, M.; Vicente, O. (2017). Effects of salinity and drought on growth, ionic relations, compatible solutes and activation of antioxidant systems in oleander (Nerium oleander L.). PLoS ONE. 12(9). doi:10.1371/journal.pone.0185017Se018501712

Ectopic cardiovascular fat in middle-aged men: effects of race/ethnicity, overall and central adiposity. The ERA JUMP study

BACKGROUND/OBJECTIVES: Higher volumes of ectopic cardiovascular fat (ECF) are associated with greater risk of coronary heart disease (CHD). Identifying factors that are associated with ECF volumes may lead to new preventive efforts to reduce risk of CHD. Significant racial/ethnic differences exist for overall and central adiposity measures which are known to be associated with ECF volumes. Whether racial/ethnic differences also exist for ECF volumes and their associations with these adiposity measures remain unclear. SUBJECTS/METHODS: Body-mass index (BMI), CT-measured ECF volumes (epicardial, pericardial and their summation), and visceral adipose tissue (VAT) were examined in a community-based sample of 1,199 middle-aged men (24.2% Caucasians, 7.0% African-Americans, 23.6% Japanese-Americans, 22.0% Japanese, 23.2% Koreans). RESULTS: Significant racial/ethnic differences existed in ECF volumes and their relationships with BMI and VAT. ECF volumes were highest among Japanese-Americans and lowest among African-Americans. The associations of BMI and VAT with ECF differed by racial/ethnic groups. Compared to Caucasians, for each 1-unit increase in BMI, African-Americans had lower whereas Koreans had higher increases in ECF volumes (P-values<0.05 for both). Meanwhile, compared to Caucasians, for each 1-unit increase in log-transformed-VAT, African-Americans, Japanese-Americans and Japanese had similar increases, whereas Koreans had a lower increase in ECF volumes (P-value<0.05). CONCLUSIONS: Racial/ethnic groups differed in their propensity to accumulate ECF at increasing level of overall and central adiposity. Future studies should evaluate whether reducing central adiposity or overall-weight will decrease ECF volumes more in certain racial/ethnic groups. Evaluating these questions might help in designing race-specific prevention strategy of CHD risk associated with higher ECF