Interannual variation in life history traits between neighbouring populations of the widespread amphibian Bufo bufo

Life-history variation within and among populations of widespread amphibian species has attracted much attention so far. In relation to a variety of problems (e.g. climate change, large-scale clines, conservation), this information is needed not only on broad geographic scale, but also at local level and from year to year. In this study, we investigated variation in body size and life history traits, including age, fecundity and egg size, in two neighbouring populations of a widespread amphibian, the Common Toad Bufo bufo, during a 3-year period. Body size varied significantly between populations in males only, but not between years. Age was assessed by skeletochronology, and osteometrical analyses revealed a complete endosteal resorption of the first line of arrested growth in 1.1 % of the individuals and a partial resorption in 77 % of the individuals. Age structures did not differ significantly between sexes, populations, nor between years. Age at first reproduction was one year later in females than in males in both populations (4 vs 3 years), but adult survival rates did not differ between sexes. Fecundity did not differ between populations or years, but egg size varied between years. Fecundity increased with size, but not with age of females. This lack of significant interpopulation variation in age structure and reproductive traits is important for monitoring local populations which can be exposed to various potential disturbance factors. On the other hand, these results stress the importance of analysing temporal variation in life history traits because one-year data may not represent properly the reproductive features of a population, and this issue is becoming more so important with the growing interest in climate changes and its possible effects on amphibian populationsLes variations intra- et interpopulationnelles des traits d'histoire de vie chez les amphibiens à grande aire de répartition font l'objet d'une attention soutenue. Pour de nombreux problèmes (e.g. les changements climatiques, variations clinales, conservation), cette information est nécessaire, non seulement à une large échelle géographique, mais aussi au niveau local et d'une année à une autre. Dans cette étude nous avons étudié durant trois années successives les variations de la taille corporelle, de l'âge et des traits d'histoire de vie, y compris la fécondité et la taille des oeufs, dans deux populations voisines du Crapaud commun Bufo bufo, une espèce à grande aire de répartition. La taille corporelle des mâles varie significativement entre les populations mais pas d'une année à une autre. L'âge a été déterminé par squelettochronologie et les analyses ostéologiques révèlent une résorption endostéale complète de la première ligne d'arrêt de croissance chez 1,1 % des individus et une résorption partielle chez 77 % des individus. Les structures d'âge ne différent pas entre les sexes, les populations, ni entre les années. Les femelles se reproduisent pour la première fois un an après les mâles dans les deux populations (4 vs 3 ans), mais le taux de survie des adultes ne diffère pas entre les sexes. La fécondité ne varie pas entre les populations ou les années, mais la taille des oeufs change d'une année à une autre. La fécondité augmente avec la taille, mais pas avec l'âge des femelles. Cette absence de variation de la structure d'âge et des paramètres de la reproduction est importante pour la surveillance des populations locales qui peuvent être exposées à divers facteurs de perturbation potentiels. Ces résultats soulignent également l'importance d'analyser les variations temporelles des traits d'histoire de vie car les données d'une année peuvent ne pas représenter correctement les caractéristiques de la reproduction d'une population, cette question étant exacerbée par l'intérêt croissant sur l'impact possible des changements climatiques sur les populations d'amphibiens

Alteration of oxidative stress parameters in red blood cells of rats after chronic in Vivo treatment with cisplatin and selenium

In this study we evaluated the possible protective effects of selenium (Se) on hematological and oxidative stress parameters in rats chronically treated with cisplatin (cisPt). Four groups of Wistar albino rats were examined: a control, untreated rats (I), rats treated with Se (II), rats treated with cisPt (III), and rats treated with Se and cisPt (IV). All animals were treated for 5 days successively and killed 24 h after the last treatment. Hematological and oxidative stress parameters were followed in whole blood and red blood cells (RBC). Results showed that the chronic application of Se was followed by a higher number of reticulocytes and platelets, increased lipid peroxidation and GSH content in the RBC. Cisplatin treatment induced depletion of RBC and platelet numbers and an elevation of the superoxide anion, nitrites and glutathione levels. Se and cisPt co-treatment was followed by an elevation of the hematological parameters and the recovery of the glutathione status when compared to the control and cisPt-treated rats

MOTOR ABILITIES OF CHILDREN IN URBAN AND RURAL AREAS

Knowledge of motor skills in young schoolchildren is directly related to the effects of physical education and the development of certain motor skills. During the younger school age, the dynamics of the development change is slower when compared to the development of preschoolers. The general mobility factor which, according to most authors, exists during the pre-school age begins to vary during the first few years of elementary school, and this is precisely the period in which children quickly develop their motor skills. The aim of this study is to determine the differences in the motor abilities of students in urban and rural areas. The sample in this study consisted of fourth-grade elementary school students (N = 120) in the municipality of Vranje. The data processing was carried out with the help of the T-test and X2 test.  What was tested was the explosive strength, speed of movement frequency, repetitive strength of the trunk and flexibility. Each test of motor ability is covered with at least three variables, and in any case, it did not happen that one group had better results in all three variables that are used for the estimation of some motor skills. Students from urban areas showed significantly better results in explosive strength of the upper limbs (MBCM) and the flexibility of the lower extremities (MDPR and MPRS). Students from rural areas showed significantly better results in speed-frequency movements of the arms and legs (MKRR and MKRN) and the repetitive strength of the trunk (MPNL and MZTL). The number of schoolchildren from urban areas who participate in sports is not significantly different from the number of schoolchildren from rural areas who are involved in sports. The difference that occurs in some variables of motor skills is most likely a consequence of specific training in the context of some field of sport, the quality of training in the field, genetics and physical activity during leisure time

GPR54 (KISS1R) Transactivates EGFR to Promote Breast Cancer Cell Invasiveness

Kisspeptins (Kp), peptide products of the Kisspeptin-1 (KISS1) gene are endogenous ligands for a G protein-coupled receptor 54 (GPR54). Previous findings have shown that KISS1 acts as a metastasis suppressor in numerous cancers in humans. However, recent studies have demonstrated that an increase in KISS1 and GPR54 expression in human breast tumors correlates with higher tumor grade and metastatic potential. At present, whether or not Kp signaling promotes breast cancer cell invasiveness, required for metastasis and the underlying mechanisms, is unknown. We have found that kisspeptin-10 (Kp-10), the most potent Kp, stimulates the invasion of human breast cancer MDA-MB-231 and Hs578T cells using Matrigel-coated Transwell chamber assays and induces the formation of invasive stellate structures in three-dimensional invasion assays. Furthermore, Kp-10 stimulated an increase in matrix metalloprotease (MMP)-9 activity. We also found that Kp-10 induced the transactivation of epidermal growth factor receptor (EGFR). Knockdown of the GPCR scaffolding protein, β-arrestin 2, inhibited Kp-10-induced EGFR transactivation as well as Kp-10 induced invasion of breast cancer cells via modulation of MMP-9 secretion and activity. Finally, we found that the two receptors associate with each other under basal conditions, and FRET analysis revealed that GPR54 interacts directly with EGFR. The stability of the receptor complex formation was increased upon treatment of cells by Kp-10. Taken together, our findings suggest a novel mechanism by which Kp signaling via GPR54 stimulates breast cancer cell invasiveness

Inherited colour vision deficiencies: From Dalton to molecular genetics

In recent years, great advances have been made in our understanding of the molecular basis of colour vision defects, as well as of the patterns of genetic variation in individuals with normal colour vision. Molecular genetic analyses have explained the diversity of types and degrees of severity in colour vision anomalies, their frequencies, pronounced individual variations in test results, etc. New techniques have even enabled the determination of John Dalton’s real colour vision defect, 150 years after his death. Inherited colour vision deficiencies most often result from the mutations of genes that encode cone opsins. Cone opsin genes are linked to chromosomes 7 (the S or “blue” gene) and X (the L or “red” gene and the M or “green” gene). The L and M genes are located on the q arm of the X chromosome in a head-to-tail array, composed of 2 to 6 (typically 3) genes - a single L is followed by one or more M genes. Only the first two genes of the array are expressed and contribute to the colour vision phenotype. The high degree of homology (96%) between the L and M genes predisposes them to unequal recombination, leading to gene deletion or the formation of hybrid genes (comprising portions of both the L and M genes), explaining the majority of the common red-green colour vision deficiencies. The severity of any deficiency is influenced by the difference in spectral sensitivity between the opsins encoded by the first two genes of the array. A rare defect, S monochromacy, is caused either by the deletion of the regulatory region of the array or by mutations that inactivate the L and M genes. Most recent research concerns the molecular basis of complete achromatopsia, a rare disorder that involves the complete loss of all cone function. This is not caused by mutations in opsin genes, but in other genes that encode cone-specific proteins, e.g. channel proteins and transducin

Implications of rbcL phylogeny for historical biogeography of genus Mercurialis L.: Estimating age and center of origin

The aim of this study was to address questions concerning the historical biogeography of the genus Mercurialis in the subfamily Acalyphoideae. Applying a molecular clock to obtained rbcL phylogeny, we estimated the minimal age of divergence of genus Mercurialis to ~65-66 Ma, placing it at the Cretaceous/Paleogene boundary. We used ancestral area analysis and dispersal-vicariance analysis to infer the center of origin of the genus. Contrary to previous hypothesis, our results show that Mercurialis originated in Indomalaya and migrated westward, while the Mediterranean area was most probably the center of ecological diversification and further speciation. Evolutionary events of vicariance and dispersals were reconstructed in a proposed scenario of divergence of Mercurialis within Acalyphoideae.