Prolonged changes in hepatic mitochondrial activity and insulin sensitivity by high fructose intake in adolescent rats

Persistence of damage induced by unhealthy diets during youth has been little addressed. Therefore, we investigated the impact of a short‐term fructose‐rich diet on liver metabolic activity in adolescent rats and the putative persistence of alterations after removing fructose from the diet. Adolescent rats were fed a fructose‐rich diet for three weeks and then switched to a control diet for further three weeks. Body composition and energy balance were not affected by fructose‐rich diet, while increased body lipids and lipid gain were found after the rescue period. Switching to a control diet reversed the upregulation of plasma fructose, uric acid, lipocalin, and haptoglobin, while plasma triglycerides, alanine aminotransferase, lipopolysaccharide, and tumor necrosis factor alpha remained higher. Hepatic steatosis and ceramide were increased by fructose‐rich diet, but reversed by returning to a control diet, while altered hepatic response to insulin persisted. Liver fatty acid synthase and stearoyl‐CoA desaturase (SCD) activities were upregulated by fructose‐rich diet, and SCD activity remained higher after returning to the control diet. Fructose‐induced upregulation of complex II‐driven mitochondrial respiration, peroxisome proliferator‐activated receptor‐gamma coactivator 1 alpha, and peroxisome proliferator activated receptor α also persisted after switching to control diet. In conclusion, our results show prolonged fructose‐induced dysregulation of liver metabolic activity

Conservation Genetics of Mediterranean Brown Trout in Central Italy (Latium): A Multi-Marker Approach

Brown trout is considered a complex of incipient species, including several phylogenetic lineages, whose natural distribution in the Mediterranean area has been altered, since the beginning of the 1900s, by massive introductions of domestic strains of Atlantic origin to support fisheries. Introduced trout naturalize in new suitable environments and extensively hybridize with native populations. Here, we characterized putatively neutral and adaptive genetic variability and popu lation structure of Mediterranean brown trout from six river catchments in central peninsular Italy, as revealed by both mitochondrial (Control Region) and nuclear (microsatellites, LDH-C1, major histocompatibility complex) markers. We quantified the admixture of wild populations with hatchery strains and evaluated the effects of domestic trout introductions on shaping population genetics. Our analyses indicated: (1) a composite picture of genetic variability in the area, with the presence of all native Mediterranean trout mitochondrial lineages (“Adriatic”, “Mediterranean”, “marmoratus”), vari ous frequencies of allochthonous genotypes and different rates of introgression among sampling sites; (2) asymmetric mito-nuclear introgression; (3) increasing nuclear marker diversity with increasing levels of admixture across populations; (4) strong population structure coupled with relatively low effective population size. Data allowed the identification of five management units and we propose specific actions to support ongoing and future conservation strategies within the examined are

Prolonged changes in hepatic mitochondrial activity and insulin sensitivity by high fructose intake in adolescent rats

Persistence of damage induced by unhealthy diets during youth has been little addressed. Therefore, we investigated the impact of a short-term fructose-rich diet on liver metabolic activity in adolescent rats and the putative persistence of alterations after removing fructose from the diet. Adolescent rats were fed a fructose-rich diet for three weeks and then switched to a control diet for further three weeks. Body composition and energy balance were not affected by fructose-rich diet, while increased body lipids and lipid gain were found after the rescue period. Switching to a control diet reversed the upregulation of plasma fructose, uric acid, lipocalin, and haptoglobin, while plasma triglycerides, alanine aminotransferase, lipopolysaccharide, and tumor necrosis factor alpha remained higher. Hepatic steatosis and ceramide were increased by fructose-rich diet, but reversed by returning to a control diet, while altered hepatic response to insulin persisted. Liver fatty acid synthase and stearoyl-CoA desaturase (SCD) activities were upregulated by fructose-rich diet, and SCD activity remained higher after returning to the control diet. Fructose-induced upregulation of complex II-driven mitochondrial respiration, peroxisome proliferator-activated receptor-gamma coactivator 1 alpha, and peroxisome proliferator activated receptor alpha also persisted after switching to control diet. In conclusion, our results show prolonged fructose-induced dysregulation of liver metabolic activity

Balancing selection, genetic drift, and human-mediated introgression interplay to shape MHC (functional) diversity in Mediterranean brown trout

The extraordinary polymorphism of major histocompatibility complex (MHC) genes is considered a paradigm of pathogen-mediated balancing selection, although empirical evidence is still scarce. Furthermore, the relative contribution of balancing selection to shape MHC population structure and diversity, compared to that of neutral forces, as well as its interaction with other evolutionary processes such as hybridization, re mains largely unclear. To investigate these issues, we analyzed adaptive (MHC-DAB gene) and neutral (11 microsatellite loci) variation in 156 brown trout (Salmo trutta complex) from six wild populations in central Italy exposed to introgression from do mestic hatchery lineages (assessed with the LDH gene). MHC diversity and structur ing correlated with those at microsatellites, indicating the substantial role of neutral forces. However, individuals carrying locally rare MHC alleles/supertypes were in bet ter body condition (a proxy of individual fitness/parasite load) regardless of the zygo sity status and degree of sequence dissimilarity of MHC, hence supporting balancing selection under rare allele advantage, but not heterozygote advantage or divergent allele advantage. The association between specific MHC supertypes and body condi tion confirmed in part this finding. Across populations, MHC allelic richness increased with increasing admixture between native and domestic lineages, indicating intro gression as a source of MHC variation. Furthermore, introgression across populations appeared more pronounced for MHC than microsatellites, possibly because initially rare MHC variants are expected to introgress more readily under rare allele advan tage. Providing evidence for the complex interplay among neutral evolutionary forces, balancing selection, and human-mediated introgression in shaping the pattern of MHC (functional) variation, our findings contribute to a deeper understanding of the evolution of MHC genes in wild populations exposed to anthropogenic disturbance

Constraining decaying dark energy density models with the CMB temperature-redshift relation

We discuss the thermodynamic and dynamical properties of a variable dark energy model with density scaling as $\rho_x \propto (1+z)^{m}$, z being the redshift. These models lead to the creation/disruption of matter and radiation, which affect the cosmic evolution of both matter and radiation components in the Universe. In particular, we have studied the temperature-redshift relation of radiation, which has been constrained using a recent collection of cosmic microwave background (CMB) temperature measurements up to $z \sim 3$. We find that, within the uncertainties, the model is indistinguishable from a cosmological constant which does not exchange any particles with other components. Future observations, in particular measurements of CMB temperature at large redshift, will allow to give firmer bounds on the effective equation of state parameter $w_{eff}$ for such types of dark energy models.Comment: 9 pages, 1 figure, to appear in the Proceedings of the 3rd Italian-Pakistani Workshop on Relativistic Astrophysics, Lecce 20-22 June 2011, published in Journal of Physics: Conference Series (JPCS

A role for suppressed thermogenesis favoring catch-up fat in the pathophysiology of catch-up growth

Catch-up growth is a risk factor for later obesity, type 2 diabetes, and cardiovascular diseases. We show here that after growth arrest by semistarvation, rats refed the same amount of a low-fat diet as controls show 1) lower energy expenditure due to diminished thermogenesis that favors accelerated fat deposition or catch-up fat and 2) normal glucose tolerance but higher plasma insulin after a glucose load at a time point when their body fat and plasma free fatty acids (FFAs) have not exceeded those of controls. Isocaloric refeeding on a high-fat diet resulted in even lower energy expenditure and thermogenesis and increased fat deposition and led to even higher plasma insulin and elevated plasma glucose after a glucose load. Stepwise regression analysis showed that plasma insulin and insulin-to-glucose ratio after the glucose load are predicted by variations in efficiency of energy use (i.e., in thermogenesis) rather than by the absolute amount of body fat or plasma FFAs. These studies suggest that suppression of thermogenesis per se may have a primary role in the development of hyperinsulinemia and insulin resistance during catch-up growth and underscore a role for suppressed thermogenesis directed specifically at catch-up fat in the link between catch-up growth and chronic metabolic diseases

Flood susceptibility assessment in a highly urbanized alluvial fan: the case study of Sala Consilina (southern Italy)

Abstract. This paper deals with the risk assessment to alluvial fan flooding at the piedmont zone of carbonate massifs of the southern Apennines chain (southern Italy). These areas are prime spots for urban development and are generally considered to be safer than the valley floors. As a result, villages and towns have been built on alluvial fans which, during intense storms, may be affected by flooding and/or debris flow processes. The study area is located at the foothills of the Maddalena mountains, an elongated NW-SE trending ridge which bounds to the east the wide intermontane basin of Vallo di Diano. The area comprises a wide detrital talus (bajada) made up by coalescent alluvial fans, ranging in age from the Middle Pleistocene to the Holocene. Historical analysis was carried out to ascertain the state of activity of the fans and to identify and map the zones most hit by past flooding. According to the information gathered, the Sala Consilina fans would appear prone to debris flows; in the past these processes have produced extensive damage and loss of life in the urban area. The watershed basins feeding the fans have very low response times and may produce debris flow events with high magnitudes. Taking into account the historical damage, the fan surface morphology, and the present urban development (street orientation and hydraulic network), the piedmont area was zoned and various susceptibility classes were detected. These results may represent a useful tool for studies aiming at territorial hazard mapping and civil protection interventions