471 research outputs found
Partial Purification of Integral Membrane Antigenic Proteins from Trypanosoma evansi
Trypanosoma evansi and Trypanosoma vivax, which are the major causative agents of animal trypanosomosis in Venezuela, have shown a very high immunological cross-reactivity. Since the production of T. vivax antigens is a limiting factor as this parasite is difficult to propagate in experimental animal models, our goal has been to identify and isolate antigens from T. evansi that cross-react with T. vivax. Here, we used the Venezuelan T. evansi TEVA1 isolate to prepare the total parasite lysate and its corresponding cytosolic and membranous fractions. In order to extract the T. evansi integral membrane proteins, the particulate portion was further extracted first with Triton X-100, and then with sodium dodecyl sulfate. After discarding the cytosolic and Triton X-100 solubilized proteins, we employed sedimentation by centrifugation on linear sucrose gradients to partially purify the sodium dodecyl sulfate-solubilized proteins from the Triton X-100 resistant particulate fraction of T. evansi. We obtained enriched pools containing polypeptide bands with apparent molecular masses of 27 kDa, 31 kDa, and 53 kDa, which were recognized by anti-T. vivax antibodies from experimentally and naturally infected bovines
A "cookbook" for vulnerability research
There is a growing need to facilitate the interdisciplinary study of the relationship between the environment and human health and well-being. It is increasingly recognized that vulnerability is a key construct allowing discipline-specific research questions on these topics to be meaningfully contextualized. However, there is little consensus regarding the meaning of the concept of vulnerability or how it can best be utilized in research studies. In this perspective article, we use the metaphor of a "cookbook" to review promising trends in vulnerability research and to make this body of research accessible to a multi-disciplinary audience. Specifically, we discuss a selection of "recipes" (theoretical frameworks), "ingredients" (vulnerability domains), "cooking tools" (qualitative and quantitative methods), and approaches to "meal presentation" (communication of results) drawn from vulnerability studies published in the past 15 years. Our aim is for this short "cookbook" to serve as a jumping-off point for scholars unfamiliar with the vulnerability literature and an inspiration for scholars more familiar with this topic to develop new ways to navigate the tension between locally-specific assessments of vulnerability and attempts at standardization. Our ultimate take-home message is that the specifics theories and methods used in vulnerability research are less important than attention to what we see as the 3 'T's of transparency, triangulation, and transferability, and to efforts to make vulnerability research both "place-based" and comparable
Analyzing the turbulent planetary boundary layer by remote sensing systems: the Doppler wind lidar, aerosol elastic lidar and microwave radiometer
he planetary boundary layer (PBL) is the lowermost
region of troposphere and is endowed with turbulent
characteristics, which can have mechanical and/or thermodynamic
origins. This behavior gives this layer great importance,
mainly in studies about pollutant dispersion and
weather forecasting. However, the instruments usually applied
in studies of turbulence in the PBL have limitations
in spatial resolution (anemometer towers) or temporal resolution
(instrumentation aboard an aircraft). Ground-based
remote sensing, both active and passive, offers an alternative
for studying the PBL. In this study we show the capabilities
of combining different remote sensing systems (microwave
radiometer – MWR, Doppler lidar – DL – and elastic lidar
– EL) for retrieving a detailed picture on the PBL turbulent
features. The statistical moments of the high frequency distributions
of the vertical wind velocity, derived from DL,
and of the backscattered coefficient, derived from EL, are
corrected by two methodologies, namely first lag correction
and -2=3 law correction. The corrected profiles, obtained
from DL data, present small differences when compared with
the uncorrected profiles, showing the low influence of noise
and the viability of the proposed methodology. Concerning
EL, in addition to analyzing the influence of noise, we explore
the use of different wavelengths that usually include
EL systems operated in extended networks, like the European
Aerosol Research Lidar Network (EARLINET),This work was supported by the Andalusia
Regional Government through project P12-RNM-2409 and by the
Spanish Agencia Estatal de Investigación (AEI) through projects
CGL2016-81092-R and CGL2017-90884-REDT. We acknowledge
the financial support by the European Union’s Horizon 2020
research and innovation program through project ACTRIS-2 (grant
agreement no. 654109)
Isolation of human bone marrow mesenchymal stem cells and evaluation of their osteogenic potential
Las células madre mesenquimatosas de médula ósea humana (abreviadas hBMSCs) constituyen una fuente de células auto-renovables con alto potencial de diferenciación, comúnmente aisladas a partir de los aspirados medulares en huesos largos. Su diferenciación hacia el linaje osteogénico, por ejemplo, ha sido ampliamente utilizada para la evaluación biológica de biomateriales o matrices con aplicaciones en la ingeniería de tejidos óseos. El objetivo de este trabajo consistió en aislar hBMSCs a partir de la cabeza femoral de pacientes sometidos a artroplastia total de cadera, así como evaluar su potencial osteogénico. Brevemente, se extrajo el hueso esponjoso y se disgregó mecánicamente; las células desprendidas se cultivaron y las células no adherentes se eliminaron luego de 4 días. El potencial osteogénico se evaluó en la quinta generación de cultivo, mediante ensayos de diferenciación a 14 y 20 días donde se compararon cultivos con y sin suplementos osteogénicos. La evaluación se realizó mediante tinción con Alizarina Roja y la cuantificación de los niveles de expresión génica de los marcadores osteogénicos colágeno tipo I, osteonectinca y sialoprotiena ósea mediante RT-PCR en tiempo real. Las hBMSCs obtenidas presentaron un fenotipo no-diferenciado estable, así como la capacidad de mineralizar la matriz extracelular y expresar un fenotipo similar al osteoblasto durante la inducción osteogénica. Los tres marcadores evaluados se sobre-expresaron en los cultivos en condiciones osteogénicas, y se encontró que cambios hasta de 2X en sus niveles de expresión son relevantes para el desarrollo del proceso de diferenciación. El modelo de hBMSCS presentado podría ser utilizado para la evaluación in vitro de la osteoinductividad de diferentes biomateriales, moléculas bioactivas o matrices para ingeniería de tejidos.Human bone marrow mesenchymal stem cells (hBMSCs) comprise a cell population capable of self-renewal and multilineage differentiation commonly isolated from bone marrow aspirates of large bones. Their osteogenic potential has been extensively exploited for the biological evaluation of scaffolds or biomaterials with applications in bone tissue engineering. This work aimed to isolate hBMSCs from femoral heads of patients undergoing total hip arthroplasty and to evaluate their osteogenic potential. Briefly, the trabecular bone was extracted and mechanically disaggregated; the released cells were cultured and non-adherent cells were removed after 4 days. The osteogenic potential was evaluated at the fifth passage after 14 and 20 days of induction, comparing cultures with and without osteogenic supplements, via Alizarin red staining and the quantification of the gene expression levels of the osteogenic markers collagen type I, osteonectin and bone sialoprotein through real-time RT-PCR. The obtained hBMSCs presented a stable undifferentiated phenotype after prolonged cell culture, matrix mineralization capabilities and expression of osteoblast phenotype upon osteogenic induction. The three markers were up-regulated in cultures under osteogenic conditions and 2 fold differences in their expression levels were found to be significant for the onset of the differentiation process. The obtained hBMSCs may have applications on the in vitro evaluation of the osteoinductivity of different biomaterials, bioactive molecules or tissue engineering scaffolds
Earthworms and Amazonian Dark Earths: improving understanding of the relationships between soil management, biodiversity and function.
Multi-layered ZIF-coated cells for the release of bioactive molecules in hostile environments
Published on 01 August 2022Metal-organic framework (MOF) coatings on cells enhance viability in cytotoxic environments. Here, we show how protective multi-layered MOF bio-composite shells on a model cell system (yeast) enhance the proliferation of living cells exposed to hostile protease-rich environments via the dissolution of the shells and release of a protease inhibitor (antitrypsin).Lei Gan, Miriam de J. Velásquez-Hernández, Anita Emmerstorfer-Augustin, Peter Wied, Heimo Wolinski, Simone Dal Zilio, Marcello Solomon, Weibin Liang, Christian Doonan, and Paolo Falcar
Detecting Machine-obfuscated Plagiarism
Related dataset is at https://doi.org/10.7302/bewj-qx93 and also listed in the dc.relation field of the full item record.Research on academic integrity has identified online paraphrasing tools as a severe threat to the effectiveness of plagiarism detection systems. To enable the automated identification of machine-paraphrased text, we make three contributions. First, we evaluate the effectiveness of six prominent word embedding models in combination with five classifiers for distinguishing human-written from machine-paraphrased text. The best performing classification approach achieves an accuracy of 99.0% for documents and 83.4% for paragraphs. Second, we show that the best approach outperforms human experts and established plagiarism detection systems for these classification tasks. Third, we provide a Web application that uses the best performing classification approach to indicate whether a text underwent machine-paraphrasing. The data and code of our study are openly available.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/152346/1/Foltynek2020_Paraphrase_Detection.pdfDescription of Foltynek2020_Paraphrase_Detection.pdf : Foltynek2020_Paraphrase_Detectio
Las proteínas del plasma seminal incrementan la viabilidad espermática post-descongelación del semen de toros Sanmartinero
RESUMEN
Objetivo. El objetivo de este trabajo fue evaluar el efecto de la adición de proteínas del plasma seminal sobre el porcentaje de espermatozoides bovinos viables post-descongelación. Materiales y métodos. Los espermatozoides se congelaron usando dos medios (citrato-fructosa-yema y Bioxcell®) y la obtención de proteínas de plasma seminal de bajo peso molecular se realizó por medio de cromatografía líquida de baja presión. Las proteínas de interés eluyeron en las fracciones 21-25 y se sometieron a electroforésis en una y dos dimensiones. Los espermatozoides se incubaron a 37°C durante una hora, con 0.5, 1.0, 1.5 y 2.0 mg de la fracción 21-25. Se incluyeron dos tratamientos adicionales: uno con proteínas totales del plasma seminal y otro sin proteína. Resultados. La electroforésis bidimensional de las fracciones confirmó la presencia de siete puntos de proteína de bajo peso molecular (14-16 kDa y punto Isoeléctrico de 5.0 - 5.5). La adición de estas proteínas aumentó 20% (p<0.05), el porcentaje de espermatozoides viables post-descongelación en muestras congeladas en medio citrato-fructosa-yema (con dosis de 1 ó 1.5 mg de proteína/106 espermatozoides), y 25% (p<0.05) en muestras congeladas en medio Bioxcell® (con dosis de 0.5 mg de proteína/106 espermatozoides). Conclusiones. Los resultados de esta investigación sugieren el posible uso de proteínas de bajo peso molecular del plasma seminal, para disminuir el efecto deletéreo de la criopreservación en los espermatozoide
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