A balance index for phylogenetic trees based on rooted quartets

Journal of Mathematical Biology - We define a new balance index for rooted phylogenetic trees based on the symmetry of the evolutive history of every set of 4 leaves. This index makes sense for...     

Comparison of the most demanding scenarios during different in-season training sessions and official matches in professional basketball players

The purpose of this study was to compare physical demands during the most demanding scenarios (MDS) of different training sessions and official matches in professional basketball players across playing positions. Thirteen professional basketball players were monitored over a 9-week competitive season using a local positioning system. Peak physical demands included total distance, distance covered at > 18 km·h^-1, distance and number of accelerations (≥ 2 m∙s^-2) and decelerations (≤ -2 m∙s^-2) over a 60-second epoch. Analysis of variance for repeated measures, Bonferroni post-hoc tests and standardised Cohen’s effect size (ES) were calculated. Overall, almost all physical demands during the MDS of training were lower (-6.2% to -35.4%) compared to official matches. The only variable that surpassed competition demands was distance covered at > 18 km·h^-1, which presented moderate (ES = 0.61, p = 0.01) and small (ES = 0.48, p > 0.05) increases during training sessions four and three days before a competition, respectively. Conversely, the two previous practices before match day presented trivial to very large decreases (ES = 0.09–2.66) in all physical demands. Furthermore, centres achieved the lowest peak value in total distance covered during matches, forwards completed the greatest peak distance at > 18 km·h^-1, and guards performed the greatest distance and number of high-intensity accelerations and decelerations. In conclusion, physical demands during the MDS of different training sessions across the microcycle failed to match or surpass peak values during official matches, which should be considered when prescribing a training process intended to optimise the MDS of match play.     

High level of male-biased Scandinavian admixture in Greenlandic Inuit shown by Y-chromosomal analysis

We have used binary markers and microsatellites on the Y chromosome to analyse diversity in a sample of Greenlandic Inuit males. This sample contains Y chromosomes typical of those found in European populations. Because the Y chromosome has a unique and robust phylogeny of a time depth that precedes the split between European and Native American populations, it is possible to assign chromosomes in an admixed population to either continental source. On this basis, 58+/-6% of these Y chromosomes have been assigned to a European origin. The high proportion of European Y chromosomes contrasts with a complete absence of European mitochondrial DNA and indicates strongly male-biased European admixture into Inuit. Comparison of the European component of Inuit Y chromosomes with European population data suggests that they have their origins in Scandinavia. There are two potential source populations: Norse settlers from Iceland, who may have been assimilated 500 years ago, and the Danish-Norwegian colonists of the eighteenth century. Insufficient differentiation between modern Icelandic and Danish Y chromosomes means that a choice between these cannot be made on the basis of diversity analysis. However, the extreme sex bias in the admixture makes the later event more likely as the source.     

In vitro culture and biochemical characterization of six trypanosome isolates from Peru and Brazil

Six trypanosomatids isolated from different geographical areas from South America (Peru and Brazil) and different vectors and reservoir hosts (the triatomine Panstrongylus chinai [TP1], Triatoma infestans [TP2], Rhodnius ecuadorensis [TP3], R. prolixus [TB1], Didelphys marsupialis [TB2]), and one from a human asymptomatic patient [TB3], were characterized using lectin agglutination, isoenzyme profile, in vitro culture final metabolite patterns, and compared with a reference strain (Trypanosoma cruzi, Maracay strain [TC]). The different isolates were cultured in vitro in Grace's medium supplemented with 10% inactivated bovine foetal serum. According to our results and the statistical study, the isolate obtained from R. ecuadorensis should be designed as a Trypanosoma rangeli sp., showing all other isolates strong similarities to T. cruzi. Between them, two clusters could be identified, strongly correlating with the geographical origin. Cluster I grouped isolates from Peru and T. cruzi reference strain, and cluster II grouped the three Brazilian isolates.     

New species of benthopelagic hydromedusae from the Weddell Sea

Four medusa species were collected by an epibenthic sledge during the "Polarstern" ANT XV/3 cruise carried out from January to March 1998 in the eastern Weddell Sea. The specimens were collected in the benthic boundary layer at depths ranging between 1,583 and 2,034 m; 2 of the species collected are new to science. The narcomedusa Sigiweddellia bathypelagica gen. nov. et sp. nov. is characterised by two types of marginal tentacles and closed marginal statocysts. The trachymedusa Voragonema laciniata sp. nov. (known only from the single holotype) is characterised by the number and irregular shape of the centripetal canals. These findings are the first to report benthopelagic hydromedusae in deep Antarctic waters. Examination of several specimens of Benthocodon pedunculata (Bigelow 1913) leads us to move it to the genus Voragonema Naumov 1971 because of the clear presence of centripetal expansions in the ring canal.     

The γ subunits of the native GABAA/benzodiazepine receptors

Subunit-specific antibodies to all the γ subunit isoforms described in mammalian brain (γ₁, γ_2S, γ_L, and γ₃) have been made. The proportion of GABA_A receptors containing each γ subunit isoform in various brain regions has been determined by quantitative immunoprecipitation. In all tested regions of the rat brain, the γ₁, and γ₃ subunits are present in considerable smaller proportion of GABA_A receptor than the γ₂ subunit. Immunocytochemistry shows that γ₁ immunoreactivity concentrates in the stratum oriens and stratum radiatum of the CA1 region of the hippocampus. In the dentate gyrus, γ₁ immunoreactivity concentrates on the outer 2/3 of the molecular layer coinciding with the localization of the axospinous synapses of the perforant pathway. In contrast, γ₃ immunoreactivity concentrates on the basket cells and other GABAergic local circuit neurons of the hilus. These cells are also rich in γ_2S. In the cerebellu, γ₁ immunolabeling was localized on the Bergmann glia. The γ_2S and γ_2L subunits are differentially expressed in various brain regions. Thus the γ_2S is highly expressed in the olfactory bulb and hippocampus whereas the γ_2L is very abundant in inferior colliculus and cerebellum, particularly in Purkinje cells, as immunocytochemistry, in situ hybridization and immunoprecipitation techniques have revealed. The γ_2S and γ_2L coexist in some brain areas and cell types. Moreover, the γ_2S and γ_2L subunits can coexist in the same GABA_A receptor pentamer. We have shown that this is the case in some GABA_A receptors expressed in cerebellar granule cells. These GABA_A receptors also have α and β subunits forming the pentamer. Immunoblots have shown that the rat γ₁, γ_2S, γ_2L and γ₃ subunits are peptides of 47, 45, 47 and 44 kDa respectively. Results also indicate that there are aging-related changes in the expression of the γ_2S and γ_2L subunits in various brain regions which suggest the existence of aging-related changes in the subunit composition of the GABA_A receptors which in turn might lead to changes in receptor pharmacology. The results obtained with the various γ subunit isoforms are discussed in terms of the high molecular and binding heterogeneity of the native GABA_A receptors in brain. Special issue dedicated to Dr. Kinya Kuriyama     

Robustness and stability of the gene regulatory network involved in DV boundary formation in the Drosophila wing

Gene regulatory networks have been conserved during evolution. The Drosophila wing and the vertebrate hindbrain share the gene network involved in the establishment of the boundary between dorsal and ventral compartments in the wing and adjacent rhombomeres in the hindbrain. A positive feedback-loop between boundary and non-boundary cells and mediated by the activities of Notch and Wingless/Wnt-1 leads to the establishment of a Notch dependent organizer at the boundary. By means of a Systems Biology approach that combines mathematical modeling and both in silico and in vivo experiments in the Drosophila wing primordium, we modeled and tested this regulatory network and present evidence that a novel property, namely refractoriness to the Wingless signaling molecule, is required in boundary cells for the formation of a stable dorsal-ventral boundary. This new property has been validated in vivo, promotes mutually exclusive domains of Notch and Wingless activities and confers stability to the dorsal-ventral boundary. A robustness analysis of the regulatory network complements our results and ensures its biological plausibility.     

Population trend and breeding biology of Montagu's Harrier Circus pygargus in a natural vegetation site in northeast Spain

Capsule Reproductive output in a natural habitat was higher than in birds breeding in cereal crops, highlighting the importance of natural habitats for the species.

Aims To evaluate breeding in a natural habitat in inland Castellon province, Spain, and compare breeding parameters with other European populations.

Methods Breeding population size in inland Castellon was recorded between 1981 and 2003. A logistic growth model was used to describe population increase. We also calculated clutch size, brood size, productivity, percentage of successful nests and fledging success for the period 1989–2003.

Results Population size increased from three pairs in 1981 to 98 pairs in 2003. During 1989–2003, productivity (2.74 ± 1.49 fledglings/pair) and percentage of successful nests (84.%) were higher than observed in other European populations.

Conclusions Our results show the importance of our study area for the conservation of this species in the Iberian Peninsula, as it might act as a source of colonists for other areas. Food and protection against predators might explain the high breeding output, which may in turn explain the rapid population growth in the area. The study also suggests that natural habitats might be important for the species elsewhere.