Mechanisms of reproductive isolation between an ant species of hybrid origin and one of its parents.

The establishment of new species by hybridization is difficult because it requires the development of reproductive isolation (RI) in sympatry to escape the homogenizing effects of gene flow from the parental species. Here we investigated the role of two pre- and two postzygotic mechanisms of RI in a system comprising two interdependent Pogonomyrmex harvester ant lineages (the H1 and H2 lineages) of hybrid origin and one of their parental species (P. rugosus). Similar to most other ants, P. rugosus is characterized by an environmental system of caste determination with female brood developing either into queens or workers depending on nongenetic factors. By contrast, there is a strong genetic component to caste determination in the H1 and H2 lineages because the developmental fate of female brood depends on the genetic origin of the parents, with interlineage eggs developing into workers and intralineage eggs developing into queens. The study of a mixed mating aggregation revealed strong differences in mating flight timing between P. rugosus and the two lineages as a first mechanism of RI. A second important prezygotic mechanism was assortative mating. Laboratory experiments also provided support for one of the two investigated mechanisms of postzygotic isolation. The majority of offspring produced from the few matings between P. rugosus and the lineages aborted at the egg stage. This hybrid inviability was under maternal influence, with hybrids produced by P. rugosus queens being always inviable whereas a small proportion of H2 lineage queens produced large numbers of adult hybrid offspring. Finally, we found no evidence that genetic caste determination acted as a second postzygotic mechanism reducing gene flow between P. rugosus and the H lineages. The few viable P. rugosus-H hybrids were not preferentially shunted into functionally sterile workers but developed into both workers and queens. Overall, these results reveal that the nearly complete (99.5%) RI between P. rugosus and the two hybrid lineages stems from the combination of two typical prezygotic mechanisms (mating time divergence and assortative mating) and one postzygotic mechanism (hybrid inviability).

Effects of sarcoptic mange on the behaviour of the red fox and influence on other fox-born zoonoses in Geneva, Switzerland

Résumé : Une épidémie de gale sarcoptique (Sarcoptes scabiei) touche le canton de Genève depuis 1996. Nous avons étudié l'impact de cette maladie sur différents caractères comportementaux du renard roux (Vulpes vulpes) : l'écologie alimentaire, les comportements spatiaux et l'activité, ainsi que les contacts sociaux. Nous avons également évalué si la gale pouvait influencer la composition et la transmission de la communauté helminthique intestinale du renard. En effet, cette espèce est l'hôte de parasites qui sont liés à des zoonoses importantes, en particulier le ténia échinocoque du renard (Echinococcus multilocularis) pour lequel Genève est considérée comme une zone de haute endémie. Durant 5 années, des carcasses de renards ont été récoltées sur l'ensemble du canton. Nous les avons disséquées et avons conservé différents échantillons pour des analyses ultérieures. Des données sur le poids, l'âge et le statut reproductif des femelles ont ainsi pu être obtenues. Les contenus stomacaux ont été analysés pour déterminer le régime alimentaire, les intestins pour collecter des helminthes, des échantillons de sang pour faire des sérologies et des échantillons de peau pour récupérer les sarcoptes. Des renards sauvages ont également été capturés et équipés de colliers émetteurs afin de déterminer leur activité et leur utilisation de l'espace. Finalement, nous avons réalisé des affûts sur des terriers et des observations nocturnes à l'aide d'un détecteur thermique afin d'étudier les contacts sociaux. Nous avons ensuite considéré tous ces aspects pour comparer les renards galeux aux individus sains. Trois catégories de gale ont été prises en compte selon l'importance de l'infection. L'épidémie a traversé le canton en 8 ans environ et elle a provoqué une forte diminution des populations de renard. Les animaux malades étaient caractérisés par un poids réduit, ils utilisaient des domaines vitaux réduits et présentaient un rythme d'activité irrégulier. En ce qui concerne le régime alimentaire, les renards galeux avaient souvent des estomacs vides ou contenant peu d'aliments d'origine animale. Cette réduction de l'alimentation ne semble pas seulement être liée à des capacités de prédation réduite, mais également à un désintérêt face à la nourriture. Tous les changements de comportement cités étaient plus marqués chez les animaux soumis à une forte infestation. Dix taxons d'helminthes ont été identifiés dans les intestins des renards analysés. Deux d'entre eux représentent un risque de santé publique: Echinococcus multilocularis et Toxocara carvis. Pour ces helminthes, nous n'avons pas identifié de différences de prévalence entre les renards galeux et les animaux sains, mais la charge parasitaire était significativement supérieure chez les individus galeux, en particulier ceux souffrant d'une infestation importante. Ceci est probablement lié à une susceptibilité accrue des individus qui présentent une condition physique amoindrie et des défenses immunitaire affaiblies. Selon nos résultats, nous pouvons conclure que la gale induit des changements comportementaux importants et que ces changements ont une influence potentielle sur la transmission de la gale elle-même, mais également sur la transmission du reste de la communauté parasitaire de l'hôte. Les individus qui souffrent d'une infestation importante sont susceptibles de provoquer une contamination de l'environnement accrue en ce qui concerne des helminthes pouvant provoquer des zoonoses. La gale apparaît être un facteur à ne pas négliger dans le cadre de la gestion de la faune sauvage, mais également en ce qui concerne des problématiques de santé publique. Summary An epidemic outbreak of sarcoptic mange (Sarcoptes scabiei) has struck the canton of Geneva since 1996. The impact of the disease on various behavioural traits of the main host, the red fox (Vulpes vulpes), was investigated: feeding ecology, spatial behaviour and activity, and social contacts. We also evaluated if mange might have an influence on the composition and transmission of the intestinal helminth community of foxes. Indeed, this species is host of parasites with potential zoonotic importance, particularly the fox tapeworm (Echinococcus multilocularis) for which Geneva is reported as endemic area. During 5 years, red fox carcasses have been collected throughout the canton. They were then dissected and various samples conserved for further analysis. Data on weight, age, and reproductive status of females were obtained. Stomach content were analysed for diet analysis, intestines to recover helminths, blood to proceed to ELISAs and skin samples to check for the presence of Sarcoptes mites. Further, wild foxes were captured and fitted with transmitters in order to determine their activity pattern and space use. Finally, we proceeded to direct observations at dens and using a thermal imaging sensor at night to gain information about social contacts. A comparison between healthy and mangy foxes was made for all these aspects. Three categories of mangy foxes were considered from moderately to severely infected. The epidemic wave crossed the canton in about 8 years and induced a significant reduction in fox densities. Mangy individuals appeared to have reduced body weights, to use more restricted home ranges and exhibited an irregular activity pattern. Regarding food, sick foxes often had empty stomachs and consumed less food items of animal origin. The reduction in food intake appeared to be linked not only to a reduced ability to hunt, but also to a reduced interest in food. The changes observed were particularly pronounced in individuals with severe infestation. Ten helminth taxa were recovered from the intestines on the analysed fox carcasses. Two of them have an importance with regard to human public health: Echinococcus multilocularis and Toxocara cams. The prevalence of these helminths did not differ between healthy and mangy foxes, however the worm burden was significantly higher in mangy foxes, particularly those with severe mange. This is probably linked to an increased susceptibility in individuals with a reduced body condition and weakened immune defences. From our observations, we can conclude that mange induces pronounced behavioural changes in the red fox, and that those changes influence the transmission risks of mange itself, but also of the rest of the parasite community of the host. Individuals with severe mange are for example likely to increase the environment contamination of free living stages of helminths with zoonotic importance. Mange appears thus to represent a factor not to be neglected for the management of wild species and for public health issues.

Foods, nutrients and the risk of oral and pharyngeal cancer.

Background:Besides tobacco and alcohol, dietary habits may have a relevant role in oral cavity and pharyngeal (OCP) cancer.Methods:We analysed the role of selected food groups and nutrients on OCP cancer in a case-control study carried out between 1997 and 2009 in Italy and Switzerland. This included 768 incident, histologically confirmed squamous cell carcinoma cases and 2078 hospital controls. Odds ratios (ORs) were estimated using logistic regression models including terms for tobacco, alcohol and other relevant covariates.Results:Significant inverse trends in risk were observed for all vegetables (OR=0.19, for the highest vs the lowest consumption) and all fruits (OR=0.39), whereas significant direct associations were found for milk and dairy products (OR=1.50), eggs (OR=1.71), red meat (OR=1.55), potatoes (OR=1.85) and desserts (OR=1.68), although trends in risk were significant only for potatoes and desserts. With reference to nutrients, significant inverse relations were observed for vegetable protein (OR=0.45, for the highest vs the lowest quintile), vegetable fat (OR=0.54), polyunsaturated fatty acids (OR=0.53), α-carotene (OR=0.51), β-carotene (OR=0.28), β-cryptoxanthin (OR=0.37), lutein and zeazanthin (OR=0.34), vitamin E (OR=0.26), vitamin C (OR=0.40) and total folate (OR=0.34), whereas direct ones were observed for animal protein (OR=1.57), animal fat (OR=2.47), saturated fatty acids (OR=2.18), cholesterol (OR=2.29) and retinol (OR=1.88). Combinations of low consumption of fruits and vegetables, and high consumption of meat with high tobacco and alcohol, led to 10- to over 20-fold excess risk of OCP cancer.Conclusion:Our study confirms and further quantifies that a diet rich in fruits and vegetables and poor in meat and products of animal origin has a favourable role against OCP cancer.

Protection from radiation-induced colitis requires MHC class II antigen expression by cells of hemopoietic origin.

Ulcerative colitis, an inflammatory bowel disease, is believed to result from a breakdown of dominant tolerance mechanisms that normally control intestinal immunity. Although CD4+ T lymphocyte subpopulations and expression of MHC class II molecules have been shown to play a role in the pathogenesis of the disease, the nature of the responsible mechanisms remains unclear. In this paper we describe a novel mouse model for inflammatory bowel disease, radiation-induced colitis, that occurs with complete penetrance 6-8 wk postinduction. A combination of high dose gamma-irradiation and lack of MHC class II expression on cells of hemopoietic origin results in development of colitis in C57BL/6 mice. Because of its versatility (due to susceptibility of mice of the widely genetically manipulated C57BL/6 background), high reproducibility, and 100% penetrance, radiation-induced colitis will be a useful mouse model for colitis and a significant tool to study dominant immunological tolerance mechanisms. Moreover, our data imply that tolerization to enteric Ags requires MHC class II mediated presentation by APC of hemopoietic origin.

Prediction of fat-free mass using bioelectrical impedance analysis in young adults from five populations of African origin.

Background/objectives:Bioelectrical impedance analysis (BIA) is used in population and clinical studies as a technique for estimating body composition. Because of significant under-representation in existing literature, we sought to develop and validate predictive equation(s) for BIA for studies in populations of African origin.Subjects/methods:Among five cohorts of the Modeling the Epidemiologic Transition Study, height, weight, waist circumference and body composition, using isotope dilution, were measured in 362 adults, ages 25-45 with mean body mass indexes ranging from 24 to 32. BIA measures of resistance and reactance were measured using tetrapolar placement of electrodes and the same model of analyzer across sites (BIA 101Q, RJL Systems). Multiple linear regression analysis was used to develop equations for predicting fat-free mass (FFM), as measured by isotope dilution; covariates included sex, age, waist, reactance and height(2)/resistance, along with dummy variables for each site. Developed equations were then tested in a validation sample; FFM predicted by previously published equations were tested in the total sample.Results:A site-combined equation and site-specific equations were developed. The mean differences between FFM (reference) and FFM predicted by the study-derived equations were between 0.4 and 0.6âeuro0/00kg (that is, 1% difference between the actual and predicted FFM), and the measured and predicted values were highly correlated. The site-combined equation performed slightly better than the site-specific equations and the previously published equations.Conclusions:Relatively small differences exist between BIA equations to estimate FFM, whether study-derived or published equations, although the site-combined equation performed slightly better than others. The study-derived equations provide an important tool for research in these understudied populations.

Speech and oromotor deficits of epileptic origin in benign partial epilepsy of childhood with rolandic spikes (BPERS). Relationship to the acquired aphasia-epilepsy syndrome.

The authors report three children who suffered temporary oromotor or speech disturbances as focal epileptic manifestations within the frame of benign partial epilepsy of childhood with rolandic spikes and review similar cases described in the literature. The deficit can occur as an initial symptom of the disorder without visible epileptic seizures and interferes in a variable way with simple voluntary oromotor functions or complex movements including speech production, depending on the exact location and spread of the discharging epileptic focus around the perisylvian region. The most severe deficit produces the anterior operculum syndrome. More subtle non-linguistic deficits such as intermittent drooling, oromotor apraxia or dysfluency, as well as linguistic ones involving phonologic production, can occur. The rapidity of onset, progression and recovery of the deficit is very variable as well as its duration and presumably reflects the degree of epileptic activity. In some cases, rapid improvement with antiepileptic medication occurs and coincidence between the paroxysmal EEG activity (which is usually bilateral) and the functional deficit is seen. The clinical and EEG profile of the seizures disorder and the dynamic of the deficit in these cases bear a strong resemblance to what is seen in the acquired epilepsy-aphasia syndrome (Landau and Kleffner). The variations in clinical symptoms appear more related to the main site, local extension and bilaterality of the epileptic foci rather than a basic difference in physiopathology.

Formation of chlorite during thrust fault reactivation. Record of fluid origin and P-T conditions in the Monte Perdido thrust fault (southern Pyrenees)

The chemical and isotopic compositions of clay minerals such as illite and chlorite are commonly used to quantify diagenetic and low-grade metamorphic conditions, an approach that is also used in the present study of the Monte Perdido thrust fault from the South Pyrenean fold-and-thrust belt. The Monte Perdido thrust fault is a shallow thrust juxtaposing upper Cretaceous-Paleocene platform carbonates and Lower Eocene marls and turbidites from the Jaca basin. The core zone of the fault, about 6 m thick, consists of intensely deformed clay-bearing rocks bounded by major shear surfaces. Illite and chlorite are the main hydrous minerals in the fault zone. Illite is oriented along cleavage planes while chlorite formed along shear veins (< 50 mu m in thickness). Authigenic chlorite provides essential information about the origin of fluids and their temperature. delta O-18 and delta D values of newly formed chlorite support equilibration with sedimentary interstitial water, directly derived from the local hanging wall and footwall during deformation. Given the absence of large-scale fluid flow, the mineralization observed in the thrust faults records the P-T conditions of thrust activity. Temperatures of chlorite formation of about 240A degrees C are obtained via two independent methods: chlorite compositional thermometers and oxygen isotope fractionation between cogenetic chlorite and quartz. Burial depth conditions of 7 km are determined for the Monte Perdido thrust reactivation, coupling calculated temperature and fluid inclusion isochores. The present study demonstrates that both isotopic and thermodynamic methods applied to clay minerals formed in thrust fault are useful to help constrain diagenetic and low-grade metamorphic conditions.

Establishment of animal models to analyze the kinetics and distribution of human tumor antigen-specific CD8⁺ T cells.

Many patients develop tumor antigen-specific T cell responses detectable in peripheral blood mononuclear cells (PBMCs) following cancer vaccine. However, measurable tumor regression is observed in a limited number of patients receiving cancer vaccines. There is a need to re-evaluate systemically the immune responses induced by cancer vaccines. Here, we established animal models targeting two human cancer/testis antigens, NY-ESO-1 and MAGE-A4. Cytotoxic T lymphocyte (CTL) epitopes of these antigens were investigated by immunizing BALB/c mice with plasmids encoding the entire sequences of NY-ESO-1 or MAGE-A4. CD8(+) T cells specific for NY-ESO-1 or MAGE-A4 were able to be detected by ELISPOT assays using antigen presenting cells pulsed with overlapping peptides covering the whole protein, indicating the high immunogenicity of these antigens in mice. Truncation of these peptides revealed that NY-ESO-1-specific CD8(+) T cells recognized D(d)-restricted 8mer peptides, NY-ESO-181-88. MAGE-A4-specific CD8(+) T cells recognized D(d)-restricted 9mer peptides, MAGE-A4265-273. MHC/peptide tetramers allowed us to analyze the kinetics and distribution of the antigen-specific immune responses, and we found that stronger antigen-specific CD8(+) T cell responses were required for more effective anti-tumor activity. Taken together, these animal models are valuable for evaluation of immune responses and optimization of the efficacy of cancer vaccines.

Les sinusites d'origine dentaire: diagnostic et prise en charge [Diagnosis and management of sinusitis of odontogenic origin]

Les sinusites maxillaires sont des infections fréquentes de la sphère ORL. On retrouve une étiologie dentaire dans environ 10% des cas. L'extension des infections dentaires dans le sinus maxillaire est possible en raison de la proximité des racines des dents postérieures avec le bas fond sinusien. Une source odontogène doit être suspectée chez les patients ayant une anamnèse de douleur ou d'infection dentaires, de soins dentaires récents et qui présentent une sinusite unilatérale prolongée ou résistant à un traitement conservateur habituel. Les infections d'origine dentaire possèdent une flore bactérienne mixte. Le diagnostic et la prise en charge nécessitent un bilan radiologique précis. Le traitement doit prendre en charge conjointement la cause dentaire et la sinusite. Un geste chirurgical peut être indiqué dans un deuxième temps afin de restaurer la fonction sinusienne. Maxillary sinusitis are common infections. A dental origin is found in about 10% of the cases. The roots of the posterior maxillary teeth are adjacent to the sinus floor. Extensions of dental infections are therefore possible to the sinus. An odontogenic source should be considered in patients with a history of dental pain or recent oral surgery and those with extended unilateral sinusitis or unilateral sinusitis resistant to conventional treatment. Maxillary sinusitis of dental origin are polymicrobial infections. Conventional radiographs and CT-scans are required for the diagnosis and proper management. Dental treatments to remove the underlying cause combined with oral antibiotics to treat the infection are required. Endoscopic or open surgery may be necessary to complete the treatment and restore adequate sinusal function.

Délire temporel systématisé et trouble auditif d'origine corticale [Systematized temporal delusion and hearing disorders of cortical origin].

We report a case of delusion characterized by a time disorientation with a constant three days advance. Five years previously, the patient had suffered a left hemisphere stroke with aphasia. The delusional belief appeared at the same time as a cortical deafness following a second right hemisphere infarction. There was severe behaviour disturbances which lasted seven months, then cleared without any other change in the clinical picture. The lesions involved the left parietal lobe as well as the temporal and insular regions of both hemispheres.

Post-traumatic stimulus suppressible myoclonus of peripheral origin.

A patient is described who presented with myoclonus of the first dorsal interosseus muscle of the right foot. This myoclonus occurred 18 months after trauma of the cutaneous branch of the deep peroneal nerve on the dorsal aspect of the foot. Tactile stimulation in the dermatome of this nerve, or an anaesthetic block of the deep peroneal nerve stopped the myoclonus. The different innervation between the efferent motor activity responsible for the movements and the sensory afference suppressing it points firmly towards involvement of central connections. However, abolition of the movement by anaesthesia suggests the presence of a peripheral ectopic generator. This finding confirms that focal myoclonus can have its origin in the peripheral nervous system and may be modulated by sensory inputs.