Pollination biology of a disjunct population of the endangered sandhills endemic <Emphasis Type="Italic">Penstemon haydenii</Emphasis> S. Wats. (Scrophulariaceae) in Wyoming,USA

We studied the breeding system and flower visitors of the endangered plant, Penstemon haydenii, at several south-central Wyoming, USA occurrences. In agreement with earlier studies of the species 300 km to the east in Nebraska, we found Wyoming plants to be self-incompatible and pollinator-dependent for sexual reproduction. Flower visitors were several species of native bees in the families Apidae (particularly bumblebees), Halictidae (small sweat bees), and Megachilidae (especially in the genus Osmia); and the masarid wasp Pseudomasaris vespoides. Especially important was Osmia brevis, an abundant megachilid bee, and one of only two species (the sweat bee Lasioglossum (Dialictus) pruinosum was the other) present at all five sites. As in Nebraska, fruit set did not differ between our experimental cross-pollination treatment and an open-pollinated control. However, unlike Nebraska, open-pollinated treatments in Wyoming produced significantly fewer seeds per fruit than the experimental out-crossing treatment. We discuss several possible explanations for seed limitation: (1) a scarcity of pollinators early in the flowering season; (2) resource competition for developing ovules on open-pollinated inflorescences but not on experimental inflorescences; (3) the deposition of self pollen through intra-inflorescence and intra-genet pollinator movements; (4) few S-alleles and mating types in the Wyoming metapopulation compared to the Nebraska metapopulation, from which it likely derives.     

Rural and urban distribution of wild and domestic carnivore stools in the context of Echinococcus multilocularis environmental exposure

In zoonotic infections, the relationships between animals and humans lead to parasitic disease with severity that ranges from mild symptoms to life-threatening conditions. In cities and their surrounding areas, this statement is truer with the overcrowding of the protagonists of the parasites’ life cycle. The present study aims to investigate the distribution of a parasite, Echinococcus multilocularis, which is the causative agent of alveolar echinococcosis, using copro-sampling in historically endemic rural settlements of the eastern part of France and in newly endemic areas including urban parks and settlements surrounding Paris. Based on 2741 morphologically identified and geolocalized copro-samples, the density of fox faeces was generally higher in the surrounding settlements, except for one rural area where the faeces were at larger density downtown in the winter. Fox faeces are rare but present in urban parks. Dog faeces are concentrated in the park entrances and in the centre of the settlements. DNA was extracted for 1530 samples that were collected and identified from fox, dog, cat, stone marten and badger carnivore hosts. Echinococcus multilocularis diagnosis and host faecal tests were performed using real-time PCR. We failed to detect the parasite in the surroundings of Paris, but the parasite was found in the foxes, dogs and cats in the rural settlements and their surroundings in the historically endemic area. A spatial structuring of the carnivore stool distribution was highlighted in the present study with high densities of carnivore stools among human occupied areas within some potentially high-risk locations.     

Evidence for Fisher's dominance theory: how many 'special cases'?

Dominance, its genetic basis and evolution has been at the heart of one of the most intense controversies in the history of genetics. For more than eighty years the existence of dominance modifiers, genetic elements controlling dominance-recessivity interactions, has been suggested as a theoretical possibility, but the modifier elements themselves have remained elusive. A recent study of the self-incompatibility locus in flowering plants provided the first empirical evidence for such genetic elements: small non-coding RNAs that control dominance-recessivity by mediating methylation of the promoter of the recessive allele. Theory has shown that several biological situations are favorable for the evolution of dominance modifiers. We argue that the elucidation of this mechanism of dominance opens up new research avenues that could lead to uncovering dominance modifiers in other genetic systems, such as genes controlling Batesian and Müllerian mimicry or host-parasite interactions, thereby shedding light on the generality of the proposed mechanism.     

Performance of distance-based DNA barcoding in the molecular identification of Primates

For comparative primatology proper recognition of basal taxa (i.e. species) is indispensable, and in this the choice of a suitable gene with high phylogenetic resolution is crucial. For the goals of species identification in animals, the cytochrome c oxidase subunit 1 (cox1) has been introduced as standard marker. Making use of the difference in intra- and interspecific genetic variation – the DNA barcoding gap – cox1 can be used as a fast and accurate marker for the identification of animal species. For the Order Primates we compare the performance of cox1 (166 sequences; 50 nominal species) in species-identification with that of two other mitochondrial markers, 16S ribosomal RNA (412 sequences, 92 species) and cytochrome b (cob: 547 sequences, 72 species). A wide gap exist between intra- and interspecific divergences for both cox1 and cob genes whereas this gap is less apparent for 16S, indicating that rRNA genes are less suitable for species delimitation in DNA barcoding. For those species where multiple sequences are available there are significant differences in the intraspecific genetic distances between different mitochondrial markers, without, however, showing a consistent pattern. We conclude that cox1 allows accurate differentiation of species and as such DNA barcoding may have an important role to play in comparative primatology.     

Papillomavirus-specific CD4+ T cells exhibit reduced STAT-5 signaling and altered cytokine profiles in patients with recurrent respiratory papillomatosis

Recurrent respiratory papillomatosis (RRP) is caused by human papillomavirus type 6 (HPV-6) or HPV-11. Specific HLA-DR haplotypes DRB1*01:02 and DRB1*03:01 are associated with the development of RRP, disease severity, and Th2-like responses to HPV early proteins. Th1-like responses to HPV proteins have been shown to be protective in animal models. Therefore, we investigated the hypothesis that RRP patients have dysfunctional Th1-like, HPV-specific T cell responses. Using MHC class II tetramers, we identified immunogenic peptides within HPV-11 early proteins. Two distinct peptides (E6(113-132) and E2(1-20)) contained DRB1*01:02- or DRB1*03:01-restricted epitopes, respectively. An additional peptide (E2(281-300)) contained an epitope presented by both alleles. Peptide binding, tetramer, and proliferation assays identified minimal epitopes within these peptides. These epitopes elicited E2/E6-specific CD4(+) T cell responses in RRP patients and healthy control subjects, allowing the isolation of HPV-specific T cell lines using tetramers. The cytokine profiles and STAT signaling of these tetramer-positive T cells were measured to compare the polarization and responsiveness of HPV-specific T cells from patients with RRP and healthy subjects. HPV-specific IFN-γ secretion was substantially lower in T cells from RRP patients. HPV-specific IL-13 secretion was seen at modest levels in T cells from RRP patients and was absent in T cells from healthy control subjects. HPV-specific T cells from RRP patients exhibited reduced STAT-5 phosphorylation and reduced IL-2 secretion, suggesting anergy. Levels of STAT-5 phosphorylation and IFN-γ secretion could be improved through addition of IL-2 to HPV-specific T cell lines from RRP patients. Therapeutic vaccination or interventions aimed at restoring Th1-like cytokine responses to HPV proteins and reversing anergy could improve clinical outcomes for RRP patients.     

Rapid assessment of adenovirus serum neutralizing antibody titer based on quantitative, morphometric evaluation of capsid binding and intracellular trafficking: population analysis of adenovirus capsid association with cells is predictive of adenovirus infectivity

Neutralizing antiviral antibodies are typically detected on the basis of inhibition of viral function, such as propagation of a viral infection or inhibition of viral gene expression. Evidence is presented that anti-adenovirus neutralizing antibodies can be evaluated by analysis of cell-associated capsids or by analysis of intracellular trafficking of the capsids within 1 h after infection. Quantitative analyses of these morphologic parameters represent rapid, broadly applicable, functional assays for the detection of anti-adenovirus neutralizing antibodies.     

Rethinking motor learning and savings in adaptation paradigms: model-free memory for successful actions combines with internal models

Although motor learning is likely to involve multiple processes, phenomena observed in error-based motor learning paradigms tend to be conceptualized in terms of only a single process: adaptation, which occurs through updating an internal model. Here we argue that fundamental phenomena like movement direction biases, savings (faster relearning), and interference do not relate to adaptation but instead are attributable to two additional learning processes that can be characterized as model-free: use-dependent plasticity and operant reinforcement. Although usually "hidden" behind adaptation, we demonstrate, with modified visuomotor rotation paradigms, that these distinct model-based and model-free processes combine to learn an error-based motor task. (1) Adaptation of an internal model channels movements toward successful error reduction in visual space. (2) Repetition of the newly adapted movement induces directional biases toward the?repeated movement. (3) Operant reinforcement through association of the adapted movement with successful error reduction is responsible for savings.