33 research outputs found

    Environmental variables, habitat discontinuity and life history shaping the genetic structure of Pomatoschistus marmoratus

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    Coastal lagoons are semi-isolated ecosystems exposed to wide fluctuations of environmental conditions and showing habitat fragmentation. These features may play an important role in separating species into different populations, even at small spatial scales. In this study, we evaluate the concordance between mitochondrial (previous published data) and nuclear data analyzing the genetic variability of Pomatoschistus marmoratus in five localities, inside and outside the Mar Menor coastal lagoon (SE Spain) using eight microsatellites. High genetic diversity and similar levels of allele richness were observed across all loci and localities, although significant genic and genotypic differentiation was found between populations inside and outside the lagoon. In contrast to the FST values obtained from previous mitochondrial DNA analyses (control region), the microsatellite data exhibited significant differentiation among samples inside the Mar Menor and between lagoonal and marine samples. This pattern was corroborated using Cavalli-Sforza genetic distances. The habitat fragmentation inside the coastal lagoon and among lagoon and marine localities could be acting as a barrier to gene flow and contributing to the observed genetic structure. Our results from generalized additive models point a significant link between extreme lagoonal environmental conditions (mainly maximum salinity) and P. marmoratus genetic composition. Thereby, these environmental features could be also acting on genetic structure of coastal lagoon populations of P. marmoratus favoring their genetic divergence. The mating strategy of P. marmoratus could be also influencing our results obtained from mitochondrial and nuclear DNA. Therefore, a special consideration must be done in the selection of the DNA markers depending on the reproductive strategy of the species

    Evidence for Positive Selection in Putative Virulence Factors within the Paracoccidioides brasiliensis Species Complex

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    Paracoccidioides brasiliensis is a dimorphic fungus that is the causative agent of paracoccidioidomycosis, the most important prevalent systemic mycosis in Latin America. Recently, the existence of three genetically isolated groups in P. brasiliensis was demonstrated, enabling comparative studies of molecular evolution among P. brasiliensis lineages. Thirty-two gene sequences coding for putative virulence factors were analyzed to determine whether they were under positive selection. Our maximum likelihood–based approach yielded evidence for selection in 12 genes that are involved in different cellular processes. An in-depth analysis of four of these genes showed them to be either antigenic or involved in pathogenesis. Here, we present evidence indicating that several replacement mutations in gp43 are under positive balancing selection. The other three genes (fks, cdc42 and p27) show very little variation among the P. brasiliensis lineages and appear to be under positive directional selection. Our results are consistent with the more general observations that selective constraints are variable across the genome, and that even in the genes under positive selection, only a few sites are altered. We present our results within an evolutionary framework that may be applicable for studying adaptation and pathogenesis in P. brasiliensis and other pathogenic fungi

    HealthCall for the smartphone: technology enhancement of brief intervention in HIV alcohol dependent patients

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    Background: Heavy drinking jeopardizes the health of patients in HIV primary care. In alcohol dependent patients in HIV primary care, a technological enhancement of brief intervention, HealthCall administered via interactive voice response (HealthCall-IVR) was effective at reducing heavy drinking. The smartphone offered a technology platform to improve HealthCall. Methods: Working with input from patients, technology experts, and HIV clinic personnel, we further developed HealthCall, harnessing smartphone technological capacities (HealthCall-S). In a pilot study, we compared rates of HealthCall-S daily use and drinking outcomes in 41 alcohol dependent HIV-infected patients with the 43 alcohol dependent HIV-infected patients who used HealthCall-IVR in our previous efficacy study. Procedures, clinic, personnel, and measures were largely the same in the two studies, and the two groups of patients were demographically similar (~90% minority). Results: Pilot patients used HealthCall-S a median of 85.0% of the 60 days of treatment, significantly greater than the corresponding rate (63.8%) among comparison patients using HealthCall-IVR (p < .001). Mean end-of-treatment drinks per drinking day was similar in the two groups. Patients were highly satisfied with HealthCall-S (i.e., 92% reported that they liked using HealthCall-S). Conclusions: Among alcohol dependent patients in HIV primary care, HealthCall delivered via smartphone is feasible, obtains better patient engagement than HealthCall-IVR, and is associated with decreased drinking. In HIV primary care settings, HealthCall-S may offer a way to improve drinking outcomes after brief intervention by extending patient engagement with little additional demands on staff time

    Adaptive peaks in a flat-fish: Adaptive divergence overcoming gene flow

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    Immunocytochemical evaluation of the percentage of proliferating cells in pathological bone marrow and peripheral blood samples with the Ki-67 and anti-bromo-deoxyuridine monoclonal antibodies.

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    The monoclonal antibody Ki-67, directed against a nuclear antigen expressed by dividing cells in all the phases of cell cycle except G0 and early G1, was used in combination with an anti-BrdU monoclonal antibody, reacting selectively with cells in S-phase, for assessing the percentage of proliferating cells in bone marrow and peripheral blood samples from patients with lymphoma, leukaemia and multiple myeloma. Immunocytochemical labelling of proliferating cells was performed on marrow frozen sections and/or cytospins using an immunoalkaline phosphatase (APAAP) technique that made it possible to obtain proliferative index measurements in a few hours in contrast to the 3-7 d needed with tritiated thymidine. In the 54 marrow lymphoma cases studied a highly significant correlation was observed between the proportion of Ki-67 (+) cells and the separation into low- and high-grade malignant lymphomas according to the Kiel classification. In patients with multiple myeloma at the first diagnosis, the percentage of Ki-67 (+) cells was low (6-10%). In contrast, a high percentage of Ki-67 (+) cells (40-50%) was observed in a young adult with multiple myeloma, in a patient who first presented at the clinical observation with an extradural mass and in three patients who developed extramedullary masses several years after the initial diagnosis of myeloma. In acute lymphoblastic leukaemias of common type the mean value of Ki-67 labelling was 31.3%. Because of their simplicity and rapidity, immunocytochemical techniques may be expected to replace autoradiography and flow cytometry for the detection of proliferating cells in haematological samples
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