212 research outputs found

    Evolution of MHC class I genes in the endangered loggerhead sea turtle (Caretta caretta) revealed by 454 amplicon sequencing

    Get PDF
    Background: In evolutionary and conservation biology, parasitism is often highlighted as a major selective pressure. To fight against parasites and pathogens, genetic diversity of the immune genes of the major histocompatibility complex (MHC) are particularly important. However, the extensive degree of polymorphism observed in these genes makes it difficult to conduct thorough population screenings. Methods: We utilized a genotyping protocol that uses 454 amplicon sequencing to characterize the MHC class I in the endangered loggerhead sea turtle (Caretta caretta) and to investigate their evolution at multiple relevant levels of organization. Results: MHC class I genes revealed signatures of trans-species polymorphism across several reptile species. In the studied loggerhead turtle individuals, it results in the maintenance of two ancient allelic lineages. We also found that individuals carrying an intermediate number of MHC class I alleles are larger than those with either a low or high number of alleles. Conclusions: Multiple modes of evolution seem to maintain MHC diversity in the loggerhead turtles, with relatively high polymorphism for an endangered species

    Induction of diploid gynogenesis in an evolutionary model organism, the three-spined stickleback (Gasterosteus aculeatus)

    Get PDF
    Background: Rapid advances in genomics have provided nearly complete genome sequences for many different species. However, no matter how the sequencing technology has improved, natural genetic polymorphism complicates the production of high quality reference genomes. To address this problem, researchers have tried using artificial modes of genome manipulation such as gynogenesis for fast production of inbred lines. Results: Here, we present the first successful induction of diploid gynogenesis in an evolutionary model system, the three-spined sticklebacks (Gasterosteus aculeatus), using a combination of UV-irradiation of the sperm and heat shock (HS) of the resulting embryo to inhibit the second meiotic division. Optimal UV irradiation of the sperm was established by exposing stickleback sperm to a UV- light source at various times. Heat shock parameters like temperature, duration, and time of initiation were tested by subjecting eggs fertilized with UV inactivated sperm 5, 10, 15, 20, 25, or 30 minutes post fertilization (mpf) to 30°C, 34°C, or 38°C for 2, 4, 6 or 8 minutes. Gynogen yield was highest when stickleback eggs were activated with 2 minutes UV-irradiated sperm and received HS 5 mpf at 34°C for 4 minutes. Conclusions: Diploid gynogenesis has been successfully performed in three-spined stickleback. This has been confirmed by microsatellite DNA analysis which revealed exclusively maternal inheritance in all gynogenetic fry tested. Ploidy verification by flow cytometry showed that gynogenetic embryos/larvae exhibiting abnormalities were haploids and those that developed normally were diploids, i.e., double haploids that can be raised until adult size

    Uso de imágenes satélite Landsat para la detección de rodales de Pinus nigra Arn. y Pinus sylvestris L. afectados por escolítidos

    Get PDF
    Medium resolution images from multispectral sensors like Landsat TM have been extensively used for decades in order to identify decline and defoliation generated by insects and other forest pests. The present work analyses the usefulness of these kinds of images to detect small-size stands of Pinus nigra Arn. and Pinus sylvestris L. affected by Scolytidae attacks. The study area was located in the Solsones region (Eastern Pyrenees), selecting 34 training zones (17 damaged small-size stands and 17 healtly small-size stands). The exploratory analysis of the images was conducted with the ERDAS® IMAGINE 8.x. program.The results of the study showed significant differences between the affected and non-affected stands in 5 of the 7 spectral bands analysed. TM5 and TM7 bands were identified as those having the highest power to detect damaged stands. The digital levels obtained and the spaces of characteristics created, both showed trends to group small-size affected stands versus healthy, achieving improvements in the methodological procedure employed.El uso de imágenes procedentes de sensores multiespectrales de resolución media como es el caso de Landsat TM ha sido ampliamente utilizado desde décadas para detectar, entre otras variables, el decaimiento y la defoliación provocada por plagas y enfermedades forestales. El presente trabajo evalúa la utilidad del uso de estas imágenes en la detección de rodales de pino laricio (Pinus nigra Arn.) y pino silvestre (Pinus sylvestris L.) afectados por escolítidos. El área de estudio se localizó en el Solsonés (prepirineo de Lleida) seleccionando 34 áreas de entrenamiento (17 rodales afectados por la plaga y 17 rodales sanos). El análisis exploratorio de las imágenes se realizó mediante el programa ERDAS® IMAGINE 8.x. Los resultados del estudio mostraron una significación espectral en 5 de las 7 bandas analizadas, siendo TM5 y TM7 las que mejor comportamiento presentaron. Los niveles digitales obtenidos y los espacios de características creados señalaron sendas tendencias al agrupamiento de rodales afectados versus sanos, consiguiéndose plantear mejoras en el procedimiento metodológico

    Adrenalectomía laparoscópica por metástasis metácrona. Experiencia en 12 casos

    Get PDF
    To assess the peroperative and oncological results of laparoscopic adrenalectomy for an isolated metastasis. MATERIAL AND METHODS: A retrospective, descriptive study was conducted of 12 laparoscopic adrenalectomies performed for metastases out of a total of 40 adrenalectomies performed from May 1998 to April 2009. The primary tumor was pulmonary in 7 patients, renal in 3, and colonic in 2. Demographic data collected included median age, operating time, blood loss, complications, tumor size, and length of hospital stay. The Kaplan-Meier method was used to analyze survival. RESULTS: Operating time was 150 min (range, 90-206). Peroperative bleeding was 60 ml (range, 15-150). Peroperative complications occurred in 3% of patients. Tumor size was 4.5 cm (range, 1.3-8.5). No positive margins were seen in the resected specimens. Hospital stay was 3 days (range 3-5). Actuarial survival was 55.6% at 23 months (range, 2-38) with mean and median follow-up times of 20.9 and 23 months. CONCLUSIONS: In selected patients, laparoscopic adrenalectomy for metastasis is a safe procedure with oncological results superimposable to those of open surgery

    Nefrectomía parcial laparoscópica. Análisis de los primeros 30 casos de nuestra serie y revisión de la literatura

    Get PDF
    Objective: Our goal is to analyze the surgical and clinicopathological results of our first 30 laparoscopic partial nephrectomies (LPN) performed consecutively and correlate the results with the literature. Material and methods: This is a cases series, with 30 patients (20 men and 10 women) operated between 2006 and 2008. We assessed the clinicopathological factors and complications. The mean and median follow-up was 25 and 5 months. Results: Resected tumors had an average size of 2.4 cm. 60% of the tumors were malignant. The pathological stage was pT1 in 100% of cases (47% grade I, 53% Fuhrman grade II). Surgical margins were positive in 3 cases, switching to open surgery. Intraoperative bleeding was 74.66 cc (35.7±SD) and 70 cc of mean and median. The mean operative time was 214.4min (±69) and ischemia time of 31.3min (±13.8). Conclusions: Our results are similar to those reported in the literature, except for positive margins and conversion attributable to the learning curve

    Transcriptome profiling of immune tissues reveals habitat-specific gene expression between lake and river sticklebacks

    Get PDF
    The observation of habitat-specific phenotypes suggests the action of natural selection. The three-spined stickleback (Gasterosteus aculeatus) has repeatedly colonized and adapted to diverse freshwater habitats across the northern hemisphere since the last glaciation, while giving rise to recurring phenotypes associated with specific habitats. Parapatric lake and river populations of sticklebacks harbour distinct parasite communities, a factor proposed to contribute to adaptive differentiation between these ecotypes. However, little is known about the transcriptional response to the distinct parasite pressure of those fish in a natural setting. Here, we sampled wild-caught sticklebacks across four geographical locations from lake and river habitats differing in their parasite load. We compared gene expression profiles between lake and river populations using 77 whole-transcriptome libraries from two immune-relevant tissues, the head kidney and the spleen. Differential expression analyses revealed 139 genes with habitat-specific expression patterns across the sampled population pairs. Among the 139 differentially expressed genes, eight are annotated with an immune function and 42 have been identified as differentially expressed in previous experimental studies in which fish have been immune challenged. Together, these findings reinforce the hypothesis that parasites contribute to adaptation of sticklebacks in lake and river habitats

    Mechanism of action of probiotics

    Get PDF
    The modern diet doesn't provide the required amount of beneficial bacteria. Maintenance of a proper microbial ecology in the host is the main criteria to be met for a healthy growth. Probiotics are one such alternative that are supplemented to the host where by and large species of Lactobacillus, Bifidobacterium and Saccharomyces are considered as main probiotics. The field of probiotics has made stupendous strides though there is no major break through in the identification of their mechanism of action. They exert their activity primarily by strengthening the intestinal barrier and immunomodulation. The main objective of the study was to provide a deep insight into the effect of probiotics against the diseases, their applications and proposed mechanism of action
    corecore