Detection and evaluation of temperature effects on cell proliferation in somatic tissues of the eastern oyster, Crassostrea virginica, by flow cytometry

The goal of this thesis was to evaluate temperature effects on cell proliferation of eastern oyster somatic tissues for the development of an oyster cell line. Understanding the in vivo cell proliferation of an organism is essential for the development of cell culture. Cell proliferation can be measured by identifying nuclear cellular proteins involved in growth regulation and cellular transformation. The primary objectives of this study were to: 1) develop an assay to evaluate cell proliferation, 2) develop an assay to analyze nuclear RNA content, and 3) evaluate temperature effects on cell proliferation in somatic tissues. Proliferating cell nuclear antigen was detected in all the phases of the cell cycle of the eastern oyster. The concentrations of PCNA increased from G0/G1 phase into the S phase, where it peaked in mid-S phase, and decreased in G2/M phase. The immunohistochemically stained slides were analyzed using image analysis and compared to the flow cytometric detection of PCNA. Overall, flow cytometry was superior to immunohistochemistry in time and cost efficiency, and in sensitivity to the detection of PCNA in oyster somatic tissues. A flow cytometric assay was developed to detect nuclear RNA in oyster somatic tissues. Nuclear RNA was detected in all the phases of the cell cycle of the eastern oyster. The amount of nuclear RNA increased from G0/G1 phase into the S phase, where it peaked in mid-S phase, and decreased in G2/M phase. Temperature effects on cell cycle, proliferation, and cell metabolism of oyster somatic tissues were evaluated. The cell cycle analysis of the heart and labial palps cells showed that the G0/G1-phase cells decreased as the S-phase and G2/M-phase cells increased. The cell cycle analysis of both tissues also showed the opposite effect, as G0/G1-phase cells increased the S-phase and G2/M-phase cells decreased. Heart and labial palps cells for oysters held between 10°C and 25°C increased in cell proliferation after one week of temperature fluctuation. The nuclear RNA/DNA ratio at all phases of the cell cycle for heart and labial palps cells for oysters between 15°C and 20°C was higher than at all other temperature regimes. Temperature fluctuations affected the cell cycle, proliferation, and the metabolic condition of oyster somatic cells.These results support the use of flow cytometry for the analysis of cell cycle, cell proliferation, and cell metabolism. The results also suggested that temperature fluctuation has an effect on cell cycle, cell proliferation, and cell metabolism. Future research needs to focus on improving the current in vivo study and adapt the assays for cultured cells

THE RELEVANCE OF INTERACTIONS IN INNOVATION SYSTEMS: HOW TO CONSOLIDATE THE FRAMEWORK

Innovation Systems constitute an analysis framework which tries to identify the agents, and the interactions produced among them within an innovation system, endowing thus authorities of a tool for the definition of innovation policies. Accordingly, cooperation or interaction related practices become crucial. However, there is a need for the development and implementation of a more sophisticated measures and indicators as regards these interactive patterns, both from a theoretical and a quantitative approach. This papers aims at empirically contributing to highlight the relevance of these interactions. In order to do that, we first start by offering a clear taxonomy of the Spanish regions concerning R&D and innovation activities, to then analyse the extent to which interactions are relevant or not by considering in this case Spain as the unit of analysis between 1995-2002.Innovation Systems, Interactions, Innovation Networks, Measures

Assessing strength and power in resistance training

Maximal Dynamic Strength is usually assessed either by the one repetition maximum test (1-RM) or by a repetition maximum test with submaximal loads, which requires the application of a formula to estimate the value of 1-RM. This value is needed to establish the objective of resistance training: such as maximum strength, endurance strength, and/or explosive strength. However, both 1-RM and submaximal tests are unable to highlight the changes produced on power and velocity. This manuscript summarizes and reviews several common strength testing protocols and proposes a novel approach that may offer greater insight to hierarchical muscle functionalit

La contradicción de México en 2012 a los flujos de Inversión Extranjera Directa, una explicación desde las teorías del comercio internacional

Las teorías surgen como una explicación racional al mundo que nos rodea en varios semblantes. Al igual que la realidad está en constante cambio, estas deben irse adaptando al contexto actual, es decir, la realidad impone retos a la teoría. Los autores que han adoptado la Inversión Extranjera como tema de análisis y estudio, tratan de explicar el movimiento de los recursos (capital, tecnología, sistemas, etc.) a través de las fronteras internacionales y, en su mayoría, han concluido que los recursos se trasladan de los países desarrollados a los países con menores grados de desarrollo. En el 2012, una economía emergente: México, en lugar de ser una economía receptora de inversión extranjera directa, se convirtió en una exportadora de inversión directa, contraviniendo así las conclusiones de los estudios sobre los flujos de IED mundiales. Este artículo hace una revisión de algunas teorías de la inversión y del Comercio Internacional en búsqueda de una explicación a este fenómeno

Regeneration of plants from somatic embryos of Verticillium dahliae-resistant wild olive genotypes

Regeneration capacity, via somatic embryogenesis, of several wild olive genotypes differing in their response to Verticillium wilt (resistant genotypes Stop Vert, Out Vert, Ac4 and Ac 18 and the susceptible Ac 15) has been evaluated. To induce somatic embryogenesis, methodologies previously used in cultivated (high ratio cytokinin/auxin) or wild olive (low ratio cytokinin/auxin) were used. Obtained results revealed the importance of genotype, explant type, mineral formulation and hormonal balance in the induction process, ca. use of apical buds obtained from micropropagated shoots following the methodology of Mazri et al. (2013) in cultivated olive (4 days in liquid medium MS ½, 30 µM TDZ – 0.54 µM ANA, 8 weeks in basal medium MS ½, followed by subculturing in ECO basal medium supplemented with 0.5 µM 2iP, 0.44 µM BA and 0.25 µM IBA) was adequate to obtain somatic embryos in 2 genotypes, Stop Vert and Ac18, but no embryogenic response was observed in the other three. An analysis of genetic stability on Stop Vert, using SSR and RAPDs markers, was carried out in embryogenic callus, plants regenerated form this callus and micropropagated shoots in comparison with the mother plant. Polymorphism was only observed in the banding pattern generated by RAPDs in one of the 10 callus samples evaluated, resulting in a variation rate of 0.07%. This is the first time in which plants have been regenerated via somatic embryogenesis in wild olive.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech. Research project: Junta de Andalucía P11-AGR799