770 research outputs found

    Transferability of environmental favourability models in geographic space: The case of the Iberian desman (Galemys pyrenaicus) in Portugal and Spain

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    Transferring distribution models between different geographical areas may be problematic, as the performance of models outside their original scope is hard to predict. A modelling procedure is needed that gets the gist of the environmental descriptors of a distribution area, without either overfitting to the training data or overestimating the species’ distribution potential.We tested the transferability power of the favourability function, a generalized linear model, on the distribution of the Iberian desman (Galemys pyrenaicus) in the Iberian territories of Portugal and Spain.We also tested the effects of two of the main potential constraints on model transferability: the analysed ranges of the predictor variables, and the completeness of the species distribution data. We modelled 10 km×10km presence/absence data from Portugal and Spain separately, extrapolated each model to the other country, and compared predictions with observations. The Spanish model, despite arguably containing more false absences, showed good predictive ability in Portugal. The Portuguese model, whose predictors ranged between only a subset of the values observed in Spain, overestimated desman distribution when transferred.We discuss possible reasons for this differential model behaviour, and highlight the importance of this kind of models for prediction and conservation application

    Actinobacillus pleuropneumoniae induces SJPL cell cycle arrest in G2/M-phase and inhibits porcine reproductive and respiratory syndrome virus replication

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    Background: Porcine reproductive and respiratory syndrome virus (PRRSV) is one of the most important pathogens in the swine industry and causes important economic losses. No effective antiviral drugs against it are commercially available. We recently reported that the culture supernatant of Actinobacillus pleuropneumoniae, the porcine pleuropneumonia causative agent, has an antiviral activity in vitro against PRRSV in SJPL cells. Objectives of this study were (i) to identify the mechanism behind the antiviral activity displayed by A. pleuropneumoniae and (ii) to characterize the active molecules present in the bacterial culture supernatant. Methods: Antibody microarray analysis was used in order to point out cellular pathways modulated by the A. pleuropneumoniae supernatant. Subsequent, flow cytometry analysis and cell cycle inhibitors were used to confirm antibody microarray data and to link them to the antiviral activity of the A. pleuropneumoniae supernatant. Finally, A. pleuropneumoniae supernatant characterization was partially achieved using mass spectrometry. Results: Using antibody microarray, we observed modulations in G2/M-phase cell cycle regulation pathway when SJPL cells were treated with A. pleuropneumoniae culture supernatant. These modulations were confirmed by a cell cycle arrest at the G2/M-phase when cells were treated with the A. pleuropneumoniae culture supernatant. Furthermore, two G2/M-phase cell cycle inhibitors demonstrated the ability to inhibit PRRSV infection, indicating a potential key role for PRRSV infection. Finally, mass spectrometry lead to identify two molecules (m/z 515.2 and m/z 663.6) present only in the culture supernatant. Conclusions: We demonstrated for the first time that A. pleuropneumoniae is able to disrupt SJPL cell cycle resulting in inhibitory activity against PRRSV. Furthermore, two putative molecules were identified from the culture supernatant. This study highlighted the cell cycle importance for PRRSV and will allow the development of new prophylactic or therapeutic approaches against PRRSV

    Phylogenetic triangulation: Using predator-prey-parasite interactions to infer population history from partial genetic information

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    Phylogeographic studies, which infer population history and dispersal movements from intra-specific spatial genetic variation, require expensive and time-consuming analyses that are not always feasible, especially in the case of rare or endangered species. On the other hand, comparative phylogeography of species involved in close biotic interactions may show congruent patterns depending on the specificity of the relationship. Consequently, the phylogeography of a parasite that needs two hosts to complete its life cycle should reflect population history traits of both hosts. Population movements evidenced by the parasite's phylogeography that are not reflected in the phylogeography of one of these hosts may thus be attributed to the other host. Using the wild rabbit (Oryctolagus cuniculus) and a parasitic tapeworm (Taenia pisiformis) as an example, we propose comparing the phylogeography of easily available organisms such as game species and their specific heteroxenous parasites to infer population movements of definitive host/predator species, independently of performing genetic analyses on the latter. This may be an interesting approach for indirectly studying the history of species whose phylogeography is difficult to analyse directly

    Two New Species of \u3ci\u3eHermeuptychia\u3c/i\u3e from North America and Three Neotype Designations (Nymphalidae: Satyrinae)

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    Abstract Two new species of Hermeuptychia Forster, 1964 are described. Hermeuptychia sinuosa Grishin, sp. n. (type locality Guatemala: El Progreso, Morazán) is an isolated member of the genus that does not readily fit into known species groups, as suggested by its distinct male and female genitalia and COI DNA barcode sequences. It is distinguished from its congeners by prominently wavy submarginal lines, rounder wings and distinctive genitalia, and can typically be identified by a white dot, instead of an eyespot, near the ventral hindwing apex. Hermeuptychia occidentalis Grishin, sp. n. (type locality Mexico: Guerrero, Acapulco) belongs to the Hermeuptychia sosybius group as indicated by the presence of androconia on the dorsal surface of the wings, genitalia and COI DNA barcodes, and in addition to DNA characters, differs from its relatives in the shape of the uncus and female genitalia. Neotypes of Oreas strigata canthe Hübner, [1811] (type locality Suriname: Gelderland, Suriname River), Megisto acmenis Hübner, 1823 (type locality Argentina: Buenos Aires), and Satyrus cantheus Godart, [1824] (type locality USA: Florida, Pinellas County, St. Petersburg) and lectotype of Euptychia celmis var. bonaërensis [sic] Burmeister, 1878 (type locality Argentina: Buenos Aires) are designated. These designations establish Hermeuptychia canthe as a valid species widely distributed in South America from Colombia to Bolivia and southeast Brazil, Euptychia celmis var. bonaërensis [sic] Burmeister, 1878 as a junior objective synonym of Yphthimoides acmenis, and S. cantheus as a junior subjective synonym of Hermeuptychia sosybius (Fabricius, 1793). Papilio camerta Cramer, 1780 is treated as nomen dubium requiring further studies to determine an identity that is consistent with the original description, as it may be conspecific with Paryphthimoides poltys (Prittwitz, 1865) instead of being a Hermeuptychia species as currently assumed. Resumen Se describe dos nuevas especies de Hermeuptychia Forster, 1964. Hermeuptychia sinuosa Grishin, sp. n. (localidad tipo Guatemala: El Progreso, Morazán), es un componente aislado del género que no encaja fácilmente en los grupos de especies conocidas, como lo indica su distintiva genitalia masculina y femenina y las secuencias de ADN del código de barras COI. Se distingue de sus congéneres por tener líneas submarginales prominentemente onduladas, alas más redondas y genitales diferentes, y se puede identificar típicamente por un punto blanco, en lugar de una mancha ocular, cerca del ápice ventral del ala anterior. Hermeuptychia occidentalis Grishin, sp. n. (localidad tipo México: Guerrero, Acapulco) pertenece al grupo de Hermeuptychia sosybius como lo indica la presencia de androconia en las alas anteriores, la estructura genital y secuencias de ADN de la región del código de barras COI, y además de caracteres del ADN, se diferencia de sus parientes en la forma del uncus y la genitalia femenina. Se designa neotipos para Oreas strigata canthe Hübner, [1811] (localidad tipo Surinam: Gelderland, Río Surinam), Megisto acmenis Hübner, 1823 (localidad tipo Argentina: Buenos Aires), y Satyrus cantheus Godart, [1824] (localidad tipo Estados Unidos: Florida, Pinellas County, St. Petersburg), y el lectotipo de Euptychia celmis var. bonaërensis [sic] Burmeister, 1878 (localidad tipo Argentina: Buenos Aires). Estas designaciones establecen a Hermeuptychia canthe como una especie válida ampliamente distribuida en América del Sur desde Colombia hasta Bolivia y el sureste de Brasil, a Euptychia celmis var. bonaërensis [sic] Burmeister, 1878 como sinónimo objetivo más reciente de Yphthimoides acmenis, y a S. cantheus como sinónimo subjetivo más reciente de Hermeuptychia sosybius (Fabricius, 1793). Papilio camerta Cramer, 1780 es tratado como un nomen dubium requiriendo más estudios para determinar una identidad que sea consistente con la descripción original, ya que puede ser coespecífica con Paryphthimoides poltys (Prittwitz, 1865) en lugar de ser una especie de Hermeuptychia como se asume actualmente. COI = c oxidase subunit

    Diagnosis of training needs for an assembly company developed at the TECNM campus, Fresnillo

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    The present project on Diagnosis of Training Needs for the personnel of the APTIV company inFresnillo, Zacatecas, its general objective is to identify the training needs of workers, to know thedeficiencies that the employees of APTIV have and with this to be able to generate a specific trainingprogram according to the lack of skills and aptitudes found within the company and thus achieve anincrease in productivity and higher quality in production processes. Precise results were obtainedthat followed up on the recommendations made for each variable identified within the companythanks to measurement instruments such as surveys, data collected and conclusions obtained in thedevelopment and application of diagnostics. Particularly necessary in today's changing environment,as new technologies and flexible work practices become widespread and give rise to changes in theskills required by employees.The present project on Diagnosis of Training Needs for the personnel of the APTIV company inFresnillo, Zacatecas, its general objective is to identify the training needs of workers, to know thedeficiencies that the employees of APTIV have and with this to be able to generate a specific trainingprogram according to the lack of skills and aptitudes found within the company and thus achieve anincrease in productivity and higher quality in production processes. Precise results were obtainedthat followed up on the recommendations made for each variable identified within the companythanks to measurement instruments such as surveys, data collected and conclusions obtained in thedevelopment and application of diagnostics. Particularly necessary in today's changing environment,as new technologies and flexible work practices become widespread and give rise to changes in theskills required by employees

    Selective albumin-binding surfaces modified with a thrombin-inhibiting peptide

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    Blood-contacting medical devices have been associated with severe clinical complications, such as thrombus formation, triggered by the activation of the coagulation cascade due to the adsorption of certain plasma proteins on the surface of biomaterials. Hence, the coating of such surfaces with antithrombotic agents has been used to increase biomaterial haemocompatibility. Biomaterial-induced clotting may also be decreased by albumin adsorption from blood plasma in a selective and reversible way, since this protein is not involved in the coagulation cascade. In this context, this paper reports that the immobilization of the thrombin inhibitor D-Phe-Pro-D-Arg-D-Thr-CONH2 (fPrt) onto nanostructured surfaces induces selective and reversible adsorption of albumin, delaying the clotting time when compared to peptide-free surfaces. fPrt, synthesized with two glycine residues attached to the N-terminus (GGfPrt), was covalently immobilized onto self-assembled monolayers (SAMs) having different ratios of carboxylate-hexa(ethylene glycol)- and tri(ethylene glycol)-terminated thiols (EG6-COOH/EG3) that were specifically designed to control GGfPrt orientation, exposure and density at the molecular level. In solution, GGfPrt was able to inactivate the enzymatic activity of thrombin and to delay plasma clotting time in a concentration-dependent way. After surface immobilization, and independently of its concentration, GGfPrt lost its selectivity to thrombin and its capacity to inhibit thrombin enzymatic activity against the chromogenic substrate n-p-tosyl-Gly-Pro-Arg-p-nitroanilide. Nevertheless, surfaces with low concentrations of GGfPrt could delay the capacity of adsorbed thrombin to cleave fibrinogen. In contrast, GGfPrt immobilized in high concentrations was found to induce the procoagulant activity of the adsorbed thrombin. However, all surfaces containing GGfPrt have a plasma clotting time similar to the negative control (empty polystyrene wells), showing resistance to coagulation, which is explained by its capacity to adsorb albumin in a selective and reversible way. This work opens new perspectives to the improvement of the haemocompatibility of blood-contacting medical devices

    Toxoplasmose disseminada sepse símile em dois pacientes com AIDS

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    O presente relato descreve dois pacientes que apresentaram toxoplasmose aguda, disseminada e grave como primeira manifestação oportunista da síndrome da imunodeficiência adquirida. Os achados clínicos e laboratoriais foram similares aos de sepse ou choque séptico e, em ambos os casos houve evolução rápida para óbito. À necropsia, foi observada reação inflamatória e presença de taquizoítos e cistos de Toxoplasma gondii na maioria dos órgãos examinados.This report describes two patients who presented acute disseminated and severe toxoplasmosis as the first opportunistic disease related to acquired immunodeficiency syndrome. At admission, clinical and laboratory findings were similar to sepsis or septic shock and a fast evolutive course to death occurred in both cases. At necropsy, an inflammatory reaction and presence of a great number of Toxoplasma gondii cysts and tachyzoites were observed in most organs examined

    Evaluation of the effects of Quercetin and Kaempherol on the surface of MT-2 cells visualized by atomic force microscopy

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    AbstractThis study investigated the anti-viral effects of the polyphenolic compounds Quercetin and Kaempherol on the release of HTLV-1 from the surface of MT-2 cells. Atomic force microscopy (AFM) was used to scan the surface of the MT-2 cells. MT-2 cells were fixed with 100% methanol on round glass lamina or cleaved mica and dried under UV light and laminar flow. The images were captured on a Multimode equipment monitored by a NanoScope IIId controller from Veeco Instruments Inc operated in tapping mode and equipped with phase-imaging hardware. The images demonstrated viral budding structures 131±57nm in size, indicating profuse viral budding. Interestingly, cell-free viruses and budding structures visualized on the surface of cells were less common when MT-2 was incubated with Quercetin, and no particles were seen on the surface of cells incubated with Kaempherol. In summary, these data indicate that HTLV-1 is budding constantly from the MT-2 cell surface and that polyphenolic compounds were able to reduce this viral release. Biological samples were analyzed with crude cell preparations just after cultivation in the presence of Quercetin and Kaempherol, showing that the AFM technique is a rapid and powerful tool for analysis of antiviral activity of new biological compounds
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