N-Acetylsuccinimidylglutamate, a Cyclic Imide Form of the Peptide N-Acetylaspartylglutamate, Is Present in Low Micromolar Concentrations in Murine and Bovine CNS

Abstract: N -Acetylsuccinimidylglutamate [(asu)NAAG], a cyclic form of the peptide N -acetylaspartylglutamate (NAAG) in which the aspartyl residue is linked to glutamate via the α- and β-carboxylates, was identified and quantified by HPLC in the murine and bovine CNS. In the rat, the highest concentrations of (asu)NAAG were detected in the spinal cord (1.83 ± 0.15 pmol/mg of wet tissue weight) and brainstem (1.16 ± 0.08 pmol/mg wet weight), whereas the levels were below the limit of detection in cerebellum, hippocampus, and cerebral cortex. (Asu)NAAG was also detected in significant amounts in the superior colliculus and lateral genicutale nucleus (1.17 ± 0.05 and 0.82 ± 0.13 pmol/mg wet weight, respectively). Although the tissue content of (asu)NAAG was about three orders of magnitude lower than that of NAAG, levels of both peptides were positively correlated among different CNS regions ( r = 0.74, p < 0.003). In the rat spinal cord, (asu)NAAG levels progressively increased from week 2 to month 12 after birth. In bovine spinal cord, the contents of (asu)NAAG and NAAG were comparable in gray and white matter as well as in the dorsal and ventral horns. These results suggest that NAAG and (asu)-NAAG are closely related metabolically and raise the question of the physiological significance of such a cyclic peptide.     

Wildcat population density in NE Portugal: A regional stronghold for a nationally threatened felid

Population density data on depleted and endangered wildlife species are essential to assure their effective management and, ultimately, conservation. The European wildcat is an elusive and threatened species inhabiting the Iberian Peninsula, with fragmented populations and living in low densities. We fitted spatial capture–recapture models on camera-trap data, to provide the first estimate of wildcat density for Portugal and assess the most influential drivers determining it. The study was implemented in Montesinho Natural Park (NE Portugal), where we identified nine individuals, over a total effort of 3,477 trap-nights. The mean density estimate was 0.032 ± 0.012 wildcat/km², and density tended to increase with distance to humanized areas, often linked to lower human disturbance and domestic cat presence, with forest and herbaceous vegetation cover and with European rabbit abundance. Although, this density estimate is within the range of values estimated for protected areas elsewhere in the Iberian Peninsula, our estimates are low at the European level. When put in context, our results highlight that European wildcats may be living in low population densities across the Iberian Mediterranean biogeographic region. No phenotypic domestic or hybrid cats were detected, suggesting potentially low admixture rates between the two species, although genetic sampling would be required to corroborate this assertion. We provide evidence that Montesinho Natural Park may be a suitable area to host a healthy wildcat population, and thus be an important protected area in this species' conservation context.     

Population dynamics of two small pelagic fish in the central-south area off Chile: delayed density-dependence and biological interaction

It is widely believed that environmental variability is the main cause for fluctuations in commercially exploited small pelagic fish populations around the world. Nevertheless, density-dependent factors also can drive population dynamics. In this paper, we analyzed thirteen years of a relative abundance index of two clupeoids fish populations coexisting in the central-south area off Chile, namely the common sardine, Strangomera bentincki, and anchovy, Engraulis ringens. We applied the classical diagnostic tools of time series analysis to the observed time-series. Also, the realized per capita population growth rate was studied with the aim of detecting the feedback structure that is characterizing the population dynamics of the two species. The analysis suggests that population fluctuations of the two species have an important density-dependent component, displaying first-order (direct density-dependent) and second-order (delayed density-dependent) simultaneously. The density-dependent component explained 70.5 and 55.6 % of the realized per capita population growth rate of common sardine and anchovy, respectively. The deterministic skeleton model showed an asymptotic convergence to equilibrium density. In presence of a stochastic environment, fluctuations were reproduced for the species showing a component of fluctuation with a period of 4 year. The intrinsic dynamics of each species is typical of interacting species resulting from trophic interactions. It is postulated that the second-order dynamics of S. bentincki and E. ringens in central-south Chile, may be the result from interactions with a specialist predator (the fishing fleet), interacting with exogenous environmental factors.     

Biological characterization of the lytic cycle of actinophage φA7 in Streptomyces antibioticus

Some basic parameters of the lytic development of phage phi A7 in Streptomyces antibioticus are described. One-step growth experiments demonstrated that at 28 degrees C phi A7 has a latent period of about 60 min and an exponential growth period of about 35 min. The average burst size ranged from 70-100 plaque forming units per infected cell. At the same temperature 50% of the virions were adsorbed to germ tubes of S. antibioticus in about 10 min. This corresponds to an adsorption constant of 6.5 x 10(-10) ml/min. The phage was unable to adsorb the host at other stages of the life cycle (spores or mycelium). Divalent cations are not required for phi A7 stability but Ca2+ proved to be essential for adsorption and also for a later stage of the vegetative development of the phage.     

Pitavastatin in cardiometabolic disease: therapeutic profile

Statins effectively lower low-density lipoprotein-cholesterol (LDL-C) and reduce cardiovascular risk in people with dyslipidemia and cardiometabolic diseases such as Metabolic syndrome (MetS) or type 2 diabetes (T2D). In addition to elevated levels of LDL-C, people with these conditions often have other lipid-related risk factors, such as high levels of triglycerides, low levels of high-density lipoprotein-cholesterol (HDL-C), and a preponderance of highly atherogenic, small, dense low-density lipoprotein particles. The optimal management of dyslipidemia in people with MetS or T2D should therefore address each of these risk factors in addition to LDL-C. Although statins typically have similar effects on LDL-C levels, differences in chemical structure and pharmacokinetic profile can lead to variations in pleiotropic effects, adverse event profiles and drug-drug interactions. The choice of statin should therefore depend on the characteristics and needs of the individual patient. Compared with other statins, pitavastatin has distinct pharmacological features that translate into a broad range of actions on both apolipoprotein-B-containing and apolipoprotein-A-containing lipoproteins. Studies show that pitavastatin 1 to 4 mg is well tolerated and significantly improves LDL-C and triglyceride levels to a similar or greater degree than comparable doses of atorvastatin, simvastatin or pravastatin, irrespective of diabetic status. Moreover, whereas most statins show inconsistent effects on HDL-C levels, pitavastatin-treated patients routinely experience clinically significant elevations in HDL-C that are maintained and even increased over the long term. In addition to increasing high-density lipoprotein quantity, pitavastatin appears to improve high-density lipoprotein function and to slow the progression of atherosclerotic plaques by modifying high-density lipoprotein-related inflammation and oxidation, both of which are common in patients with MetS and T2D. When choosing a statin, it is important to note that patients with MetS have an increased risk of developing T2D and that some statins can exacerbate this risk via adverse effects on glucose regulation. Unlike many statins, pitavastatin appears to have a neutral and even beneficial effect on glucose regulation, making it a useful treatment option in this high-risk group of patients. Together with pitavastatin’s beneficial effects on the cardiometabolic lipid profile and its low potential for drug-drug interactions, this suggests that pitavastatin might be a useful lipid-lowering option for people with cardiometabolic disease.     

Reduced Global Genetic Differentiation of Exploited Marine Fish Species

Knowledge on genetic structure is key to understand species connectivity patterns and to define the spatiotemporal scales over which conservation management plans should be designed and implemented. The distribution of genetic diversity (within and among populations) greatly influences species ability to cope and adapt to environmental changes, ultimately determining their long-term resilience to ecological disturbances. Yet, the drivers shaping connectivity and structure in marine fish populations remain elusive, as are the effects of fishing activities on genetic subdivision. To investigate these questions, we conducted a meta-analysis and compiled genetic differentiation data (F_ST/Φ_ST estimates) for more than 170 fish species from over 200 published studies globally distributed. We modeled the effects of multiple life-history traits, distance metrics, and methodological factors on observed population differentiation indices and specifically tested whether any signal arising from different exposure to fishing exploitation could be detected. Although the myriad of variables shaping genetic structure makes it challenging to isolate the influence of single drivers, results showed a significant correlation between commercial importance and genetic structure, with widespread lower population differentiation in commercially exploited species. Moreover, models indicate that variables commonly used as proxy for connectivity, such as larval pelagic duration, might be insufficient, and suggest that deep-sea species may disperse further. Overall, these results contribute to the growing body of knowledge on marine genetic connectivity and suggest a potential effect of commercial fisheries on the homogenization of genetic diversity, highlighting the need for additional research focused on dispersal ecology to ensure long-term sustainability of exploited marine species.     

Exploring the global decline of music education

This article seeks to explain the disjuncture between the decline of music education in schools and the importance music has in popular youth culture and in creativity within the new knowledge economy. The data discussed in this article have been derived from analyses of major documents on curriculum reform as well as e-mail responses from music educators around the world. This analysis reveals that these music educators agree with the perception of a demise in music education around the world, as well as the significance of the disjuncture alluded to. The four major reasons found for the decline in music education are: (1) the model of curriculum supported in educational reforms; (2) an emphasis on standardized evaluation; (3) less resources available; and (4) a wrong approach on music advocacy.