A late burst of colour evolution in a radiation of songbirds (Passeriformes: Parulidae) suggests secondary contact drives signal divergence.

Evolutionary radiations provide important insights into species diversification, which is especially true of adaptive radiations. New World wood warblers (Parulidae) are a family of small, insectivorous, forest-dwelling passerine birds, often considered an exemplar of adaptive radiation due to their rapid diversification followed by a slowdown. However, they deviate from the expectations of an adaptive radiation scenario due to the lack of conspicuous morphological and ecological differentiation. We fitted several macroevolutionary models to trait data in 105 species of wood warblers. We tested whether morphological traits underwent an early burst of evolution (suggesting adaptation to new ecological niches in adaptive radiations) and whether song and colour underwent a diversity-dependent acceleration of trait evolutionary rate (consistent with reproductive interference driving signal evolution). Morphology and song evolved gradually under stabilizing selection, suggesting niche conservatism, with morphology possibly acting as a constraint on song evolution. In contrast, many feather colour traits underwent a diversity-dependent burst of evolution occurring late in the clade's history. We suggest that a two-step process has led to the remarkable diversification of wood warblers. First, their early diversification probably proceeded by allopatric speciation. Second, feather colour divergence likely occurred during secondary contact after range expansion. This diversification of signalling traits might have facilitated species coexistence, in combination with behavioural niche partitioning. Wood warblers seem to present characteristics of both adaptive and non-adaptive radiations.

Acoustic camouflage increases with body size and changes with bat echolocation frequency range in a community of nocturnally active Lepidoptera.

Body size is an important trait in predator-prey dynamics as it is often linked to detection, as well as the success of capture or escape. Larger prey, for example, often runs higher risk of detection by their predators, which imposes stronger selection on their anti-predator traits compared to smaller prey. Nocturnal Lepidoptera (moths) vary strongly in body size, which has consequences for their predation risk, as bigger moths return stronger echoes for echolocating bats. To compensate for increased predation risk, larger moths are therefore expected to have improved anti-predator defences. Moths are covered by different types of scales, which for a few species are known to absorb ultrasound, thus providing acoustic camouflage. Here, we assessed whether moths differ in their acoustic camouflage in a size-dependent way by focusing on their body scales and the different frequency ranges used by bats. We used a sonar head to measure 3D echo scans of a total of 111 moth specimens across 58 species, from eight different families of Lepidoptera. We scanned all the specimens and related their echo-acoustic target strength to various body size measurements. Next, we removed the scales covering the thorax and abdomen and scanned a subset of specimens again to assess the sound absorptive properties of these scales. Comparing intact specimens with descaled specimens, we found almost all species to absorb ultrasound, reducing detection risk on average by 8%. Furthermore, the sound absorptive capacities of body scales increased with body size suggesting that larger species benefit more from acoustic camouflage. The size-dependent effect of camouflage was in particular pronounced for the higher frequencies (above 29 kHz), with moth species belonging to large-bodied families consequently demonstrating similar target strengths compared to species from small-bodied families. Finally, we found the families to differ in frequency range that provided the largest reduction in detection risk, which may be related to differences in predation pressure and predator communities of these families. In general, our findings have important implications for predator-prey interactions across eco-evolutionary timescales and may suggest that acoustic camouflage played a role in body size evolution of nocturnally active Lepidoptera.

Prevalence of and risk factors for acute mountain sickness among a cohort of high-altitude travellers who received pre-travel counselling.

BACKGROUND: Acute mountain sickness (AMS) is common in high-altitude travellers, and may lead to life-threatening high-altitude cerebral oedema. To better target pre-travel counselling, we aimed to characterize the risk factors for AMS that may be identified prior to departure. METHODS: We performed a descriptive study of high-altitude travellers who consulted at a travel clinic before departure. Data were collected by phone after their return, using a standardized questionnaire. RESULTS: 162 adults were enrolled. Most subjects (81.5%) were informed about AMS before departure, by a medical doctor in 40% of cases. AMS symptoms were reported by 77 travellers (47.5%). Variables significantly associated with AMS symptoms were female sex (56% versus 38.5%, p = 0.01), trip organised by a travel agency (55.2% versus 43.3%, p = 0.03), travel duration (mean, 4.2 ± 3.5 weeks in patients with AMS, versus 6.6 ± 7.5 weeks in patients without AMS, p = 0.014), and acetazolamide use (71.4% versus 47.5%, p = 0.045). In multivariate analysis, only female sex was independently predictive of AMS (adjusted OR 2.15 [1.14-4.40]). CONCLUSIONS: AMS symptoms occur in almost half of high-altitude travellers. Women, and travellers leaving for short duration, within trips organised by travel agencies, should be targeted for enhanced pre-travel counselling to prevent AMS.

[The natural story of tuberculosis]. / Histoire naturelle de la tuberculose.

Tuberculosis is one of the infectious diseases that had a huge impact on the health of the populations since the XVIIth century, and this remains true for most of the people in the World in 2012. Its natural story involves: contamination (inhalation of infectious particles, the Pflügge droplets, originating from a patient with bacillary tuberculosis); primary infection (remarkable by initial unresponsiveness of the immune system, followed by strong cellular immunity development within 3 to 9 weeks); latent tuberculosis infection, non-contagious and totally asymptomatic, with efficient control of tuberculosis bacilli replication, lasting for life in more than 90% of cases; and less frequently, tuberculosis disease in patients with insufficient immunity, including children less than 5 years, immunocompromised, and patients recently infected.

Human dental pulp stem cells differentiate into neural crest-derived melanocytes and have label-retaining and sphere-forming abilities.

Adult tissues contain highly proliferative, clonogenic cells that meet criteria of multipotent stem cells and are potential sources for autologous reparative and reconstructive medicine. We demonstrated that human dental pulp contains self renewing human dental pulp stem cells (hDPSCs) capable of differentiating into mesenchymal-derived odontoblasts, osteoblasts, adipocytes, and chondrocytes and striated muscle, and interestingly, also into non-mesenchymal melanocytes. Furthermore, we showed that hDPSC cultures include cells with the label-retaining and sphere-forming abilities, traits attributed to multipotent stem cells, and provide evidence that these may be multipotent neural crest stem cells.

Characterization of Mcmar1, a mariner-like element with large inverted terminal repeats (ITRs) from the phytoparasitic nematode Meloidogyne chitwoodi.

Two copies of a new mariner-like element (MLE) presenting unusual inverted terminal repeats (ITRs), Mcmar1-1 and Mcmar1-2, were cloned and sequenced in the genome of the phytoparasitic nematode Meloidogyne chitwoodi. Although the sequence features of these Mcmar1 transposons are commonplace and link them to the mariner family, at their extremities they have large 355-pb long inverted terminal repeats that are perfectly conserved. This characteristic distinguishes them from all the other MLEs so far described that have imperfectly conserved ITRs of about 26-30 bp. In consequence, the sequenced full-length Mcmar1-1 element is 2000 bp long, and comprises an uninterrupted open reading frame (ORF) that encodes a putatively active transposase with 340 amino acid residues. The Mcmar1-2 element is a deleted form of Mcmar1-1 that contains a deletion overlapping most of the internal region of the 5'ITR and the 5' region of the transposase ORF. The presence of large ITRs in different transposons related to the Tc1-mariner super-family is discussed.