Hexokinase 2, Glycogen Synthase and Phosphorylase Play a Key Role in Muscle Glycogen Supercompensation

Background: Glycogen-depleting exercise can lead to supercompensation of muscle glycogen stores, but the biochemical mechanisms of this phenomenon are still not completely understood. Methods: Using chronic low-frequency stimulation (CLFS) as an exercise model, the tibialis anterior muscle of rabbits was stimulated for either 1 or 24 hours, inducing a reduction in glycogen of 90% and 50% respectively. Glycogen recovery was subsequently monitored during 24 hours of rest. Results: In muscles stimulated for 1 hour, glycogen recovered basal levels during the rest period. However, in those stimulated for 24 hours, glycogen was supercompensated and its levels remained 50% higher than basal levels after 6 hours of rest, although the newly synthesized glycogen had fewer branches. This increase in glycogen correlated with an increase in hexokinase-2 expression and activity, a reduction in the glycogen phosphorylase activity ratio and an increase in the glycogen synthase activity ratio, due to dephosphorylation of site 3a, even in the presence of elevated glycogen stores. During supercompensation there was also an increase in 59-AMP-activated protein kinase phosphorylation, correlating with a stable reduction in ATP and total purine nucleotide levels. Conclusions: Glycogen supercompensation requires a coordinated chain of events at two levels in the context of decreased cell energy balance: First, an increase in the glucose phosphorylation capacity of the muscle and secondly, control of the enzymes directly involved in the synthesis and degradation of the glycogen molecule. However, supercompensated glycogen has fewer branches.

Rab27a: A key to melanosome transport in human melanocytes

Normal pigmentation depends on the uniform distribution of melanin-containing vesicles, the melanosomes, in the epidermis. Griscelli syndrome (GS) is a rare autosomal recessive disease, characterized by an immune deficiency and a partial albinism that has been ascribed to an abnormal melanosome distribution. GS maps to 15q21 and was first associated with mutations in the myosin-V gene. However, it was demonstrated recently that GS can also be caused by a mutation in the Rab27a gene. These observations prompted us to investigate the role of Rab27a in melanosome transport. Using immunofluorescence and immunoelectron microscopy studies, we show that in normal melanocytes Rab27a colocalizes with melanosomes. In melanocytes isolated from a patient with GS, we show an abnormal melanosome distribution and a lack of Rab27a expression. Finally, reexpression of Rab27a in GS melanocytes restored melanosome transport to dendrite tips, leading to a phenotypic reversion of the diseased cells. These results identify Rab27a as a key component of vesicle transport machinery in melanocytes.

Is football an indicator of development at the international level?

[spa] El objetivo de este trabajo es examinar si el fútbol puede ser considerado como un indicador de desarrollo a nivel internacional. Se ha diseñado un modelo econométrico empírico con el fin de analizar el desarrollo en términos de niveles de PIB per cápita y del crecimiento del PIB. Se utiliza información transversal y temporal. Los resultados sugieren que la clasificación FIFA de las selecciones nacionales se puede utilizar para complementar nuestra comprensión del desarrollo multidimensional en aquellos países donde la disponibilidad de la información no es tan buena como los investigadores quisieran.

The First World War and coal trade geography in Latin America and the Caribbean (1890-1930)

This paper aims to illustrate the dynamics of coal trade between Latin America and its main trade partners, i.e. the USA, Great Britain and Germany, before and after the enormous disruption caused by the First World War. The coal trade was used as an indicator of modernization for Latin American countries, given that oil was at that time of secondary importance. Energy imports have determined the possibilities of each Latin American country in its process of development. Here we address this question and place special emphasis on supply channels, concluding that the trade link with main suppliers was of key significance. Although this was very clear by the end of the period, the process had started well before the First World War, at least for the majority of LA&C countries. These points are developed through a gravity model applied to the bilateral coal trade. The importance of the market supplier share is addressed through cluster methodologies.

Is football an indicator of development at the international level?

[spa] El objetivo de este trabajo es examinar si el fútbol puede ser considerado como un indicador de desarrollo a nivel internacional. Se ha diseñado un modelo econométrico empírico con el fin de analizar el desarrollo en términos de niveles de PIB per cápita y del crecimiento del PIB. Se utiliza información transversal y temporal. Los resultados sugieren que la clasificación FIFA de las selecciones nacionales se puede utilizar para complementar nuestra comprensión del desarrollo multidimensional en aquellos países donde la disponibilidad de la información no es tan buena como los investigadores quisieran.

Monosomal karyotype in acute myeloid leukemia: a better indicator of poor prognosis than a complex karyotype.

PURPOSE: To investigate the prognostic value of various cytogenetic components of a complex karyotype in acute myeloid leukemia (AML). PATIENTS AND METHODS: Cytogenetics and overall survival (OS) were analyzed in 1,975 AML patients age 15 to 60 years. RESULTS: Besides AML with normal cytogenetics (CN) and core binding factor (CBF) abnormalities, we distinguished 733 patients with cytogenetic abnormalities. Among the latter subgroup, loss of a single chromosome (n = 109) conferred negative prognostic impact (4-year OS, 12%; poor outcome). Loss of chromosome 7 was most common, but outcome of AML patients with single monosomy -7 (n = 63; 4-year OS, 13%) and other single autosomal monosomies (n = 46; 4-year OS, 12%) did not differ. Structural chromosomal abnormalities influenced prognosis only in association with a single autosomal monosomy (4-year OS, 4% for very poor v 24% for poor). We derived a monosomal karyotype (MK) as a predictor for very poor prognosis of AML that refers to two or more distinct autosomal chromosome monosomies (n = 116; 4-year OS, 3%) or one single autosomal monosomy in the presence of structural abnormalities (n = 68; 4-year OS, 4%). In direct comparisons, MK provides significantly better prognostic prediction than the traditionally defined complex karyotype, which considers any three or more or five or more clonal cytogenetic abnormalities, and also than various individual specific cytogenetic abnormalities (eg, del[5q], inv[3]/t[3;3]) associated with very poor outcome. CONCLUSION: MK enables (in addition to CN and CBF) the prognostic classification of two new aggregates of cytogenetically abnormal AML, the unfavorable risk MK-negative category (4-year OS, 26% +/- 2%) and the highly unfavorable risk MK-positive category (4-year OS, 4% +/- 1%).

The key elements for genetic response in Finnish dairy cattle breeding

Selostus: Perinnöllinen edistyminen suomalaisessa lypsykarjan jalostusohjelmassa

Complexometric titration with potenciometric indicator to determination of calcium and magnesium in soil extracts¹

This study proposes a method of direct and simultaneous determination of the amount of Ca2+ and Mg2+ present in soil extracts using a Calcium Ion-Selective Electrode and by Complexometric Titration (ISE-CT). The results were compared to those obtained by conventional analytical techniques of Complexometric Titration (CT) and Flame Atomic Absorption Spectrometry (FAAS). There were no significant differences in the determination of Ca2+ and Mg2+ in comparison with CT and FAAS, at a 95 % confidence level. Additionally, results of this method were more precise and accurate than of the Interlaboratorial Control (IC).

Functionally and phylogenetically diverse plant communities key to soil biota

Recent studies assessing the role of biological diversity for ecosystem functioning indicate that the diversity of functional traits and the evolutionary history of species in a community, not the number of taxonomic units, ultimately drives the biodiversity-ecosystem-function relationship. Here, we simultaneously assessed the importance of plant functional trait and phylogenetic diversity as predictors of major trophic groups of soil biota (abundance and diversity), six years from the onset of a grassland biodiversity experiment. Plant functional and phylogenetic diversity were generally better predictors of soil biota than the traditionally used species or functional group richness. Functional diversity was a reliable predictor for most biota, with the exception of soil microorganisms, which were better predicted by phylogenetic diversity. These results provide empirical support for the idea that the diversity of plant functional traits and the diversity of evolutionary lineages in a community are important for maintaining higher abundances and diversity of soil communities.

Soil fauna as an indicator of soil quality in forest stands, pasture and secondary forest

The interactions between soil invertebrates and environmental variations are relatively unknown in the assessment of soil quality. The objective of this study was to evaluate soil quality in areas with different soil management systems, based on soil fauna as indicator, in Além Paraíba, Minas Gerais, Brazil. The soil invertebrate community was sampled using pitfall traps, in the dry and rainy seasons, from areas with five vegetation types (acacia, mimosa, eucalyptus, pasture, and secondary forest). The abundance of organisms and the total and average richness, Shannon's diversity index, the Pielou uniformity index, and change index V were determined. The fauna was most abundant in the areas of secondary forest and mimosa plantations in the dry season (111.3 and 31.7 individuals per trap per day, respectively). In the rainy season, the abundance of organisms in the three vegetation types did not differ. The highest values of average and total richness were recorded in the secondary forest in the dry season and in the mimosa stand in the rainy season. Shannon's index ranged from 1.57 in areas with acacia and eucalyptus in the rainy season to 3.19 in the eucalyptus area in the dry season. The uniformity index was highest in forest stands (eucalyptus, acacia and mimosa) in the dry season, but higher in the rainy season in the pasture and secondary forest than in the forest stands. The change index V indicated that the percentage of extremely inhibited groups was lowest in the area with mimosa, both in the dry and rainy season (36 and 23 %, respectively). Of all forest stands, the mimosa area had the most abundant soil fauna.

Frequency-dependent attenuation as a potential indicator of oil saturation

At seismic frequencies, wave-induced fluid flow is a major cause of P-wave attenuation in partially saturated porous rocks. Attenuation is of great importance for the oil industry in the interpretation of seismic field data. Here, the effects on P-wave attenuation resulting from changes in oil saturation are studied for media with coexisting water, oil, and gas. For that, creep experiments are numerically simulated by solving Biot's equations for consolidation of poroelastic media with the finite-element method. The experiments yield time-dependent stress?strain relations that are used to calculate the complex P-wave modulus from which frequency-dependent P-wave attenuation is determined. The models are layered media with periodically alternating triplets of layers. Models consisting of triplets of layers having randomly varying layer thicknesses are also considered. The layers in each triplet are fully saturated with water, oil, and gas. The layer saturated with water has lower porosity and permeability than the layers saturated with oil and gas. These models represent hydrocarbon reservoirs in which water is the wetting fluid preferentially saturating regions of lower porosity. The results from the numerical experiments showed that increasing oil saturation, connected to a decrease in gas saturation, resulted in a significant increase of attenuation at low frequencies (lower than 2 Hz). Furthermore, replacing the oil with water resulted in a distinguishable behavior of the frequency-dependent attenuation. These results imply that, according to the physical mechanism of wave-induced fluid flow, frequency-dependent attenuation in media saturated with water, oil, and gas is a potential indicator of oil saturation.

Improving telecommunication security level by integrating quantum key distribution in communication protocols

Résumé La cryptographie classique est basée sur des concepts mathématiques dont la sécurité dépend de la complexité du calcul de l'inverse des fonctions. Ce type de chiffrement est à la merci de la puissance de calcul des ordinateurs ainsi que la découverte d'algorithme permettant le calcul des inverses de certaines fonctions mathématiques en un temps «raisonnable ». L'utilisation d'un procédé dont la sécurité est scientifiquement prouvée s'avère donc indispensable surtout les échanges critiques (systèmes bancaires, gouvernements,...). La cryptographie quantique répond à ce besoin. En effet, sa sécurité est basée sur des lois de la physique quantique lui assurant un fonctionnement inconditionnellement sécurisé. Toutefois, l'application et l'intégration de la cryptographie quantique sont un souci pour les développeurs de ce type de solution. Cette thèse justifie la nécessité de l'utilisation de la cryptographie quantique. Elle montre que le coût engendré par le déploiement de cette solution est justifié. Elle propose un mécanisme simple et réalisable d'intégration de la cryptographie quantique dans des protocoles de communication largement utilisés comme les protocoles PPP, IPSec et le protocole 802.1li. Des scénarios d'application illustrent la faisabilité de ces solutions. Une méthodologie d'évaluation, selon les critères communs, des solutions basées sur la cryptographie quantique est également proposée dans ce document. Abstract Classical cryptography is based on mathematical functions. The robustness of a cryptosystem essentially depends on the difficulty of computing the inverse of its one-way function. There is no mathematical proof that establishes whether it is impossible to find the inverse of a given one-way function. Therefore, it is mandatory to use a cryptosystem whose security is scientifically proven (especially for banking, governments, etc.). On the other hand, the security of quantum cryptography can be formally demonstrated. In fact, its security is based on the laws of physics that assure the unconditional security. How is it possible to use and integrate quantum cryptography into existing solutions? This thesis proposes a method to integrate quantum cryptography into existing communication protocols like PPP, IPSec and the 802.l1i protocol. It sketches out some possible scenarios in order to prove the feasibility and to estimate the cost of such scenarios. Directives and checkpoints are given to help in certifying quantum cryptography solutions according to Common Criteria.