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102. What’s on the horizon for macroecology?

Author

Beck, J., Ballesteros-Mejia, L., Buchmann, C.M., Dengler, J., Fritz, S.A., Gruber, B., Hof, C., Jansen, F., Knapp, Sonja, Kreft, H., Schneider, A.-K., Winter, Marten, Dormann, Carsten, Beck, J., Ballesteros-Mejia, L., Buchmann, C.M., Dengler, J., Fritz, S.A., Gruber, B., Hof, C., Jansen, F., Knapp, Sonja, Kreft, H., Schneider, A.-K., Winter, Marten, and Dormann, Carsten

Abstract

Over the last two decades, macroecology - the analysis of large-scale, multi-species ecological patterns and processes - has established itself as a major line of biological research. Analyses of statistical links between environmental variables and biotic responses have long and successfully been employed as a main approach, but new developments are due to be utilized. Scanning the horizon of macroecology, we identified four challenges that will probably play a major role in the future. We support our claims by examples and bibliographic analyses. (i) Integrating the past into macroecological analyses, e.g. by using paleontological or phylogenetic information or by applying methods from historical biogeography, will sharpen our understanding of the underlying reasons for contemporary patterns. (ii) Explicit consideration of the local processes that lead to the observed larger-scale patterns is necessary to understand the fine-grain variability found in nature, and will enable better prediction of future patterns (e.g. under environmental change conditions). (iii) Macroecology is dependent on large-scale, high quality data from a broad spectrum of taxa and regions. More available data sources need to be tapped and new, small-grain large-extent data need to be collected. (iv) Although macroecology already lead to mainstreaming cutting-edge statistical analysis techniques, we find that more sophisticated methods are needed to account for the biases inherent to sampling at large scale. Bayesian methods may be particularly suitable to address these challenges. To continue the vigorous development of the macroecological research agenda, it is time to address these challenges and to avoid becoming too complacent with current achievements.

Published
2012

123. TP53 PATHOGENIC VARIANTS RELATED TO CANCER

Author

Rosero C.Y., Mejia L.G., and Corredor M.

Subjects
neoplasms, nuclear phosphoprotein p53, tumor suppressor, mutation, clinvar, uniprot, Genetics, QH426-470
Abstract

TP53 or P53 is a tumor suppressor gene known as the “genome guardian”, responsible for inducing cell response to DNA damage, by stopping the cell cycle in case of mutation, activating DNA repair enzymes, initiating senescence and activation of apoptosis. Mutations in the gene sequence can cause non-synonymous mutations or errors in the reading frame by insertion, deletion or displacement of nucleotides: e.g., c.358A>G mutation in exon 4 and variants located in exons 9 and 10 of the TD domain. Therefore, in this review, we will see that changes in the reading frame, including the loss of one or two base pairs could prevent accurate transcription or changes in the structure and function of the protein, and could completely impair reparation function. These changes promote self-sufficiency in growth signaling, insensitivity to anti-growth signals, and evasion of apoptosis, resulting in limitless replication and induction of metastatic angiogenesis, generating as a consequence the proliferation of tumor, neoplastic, and lymphoid cells. Taking into account the importance of TP53 in the regulation of the cell cycle, the objective of this review is to update information related to the role of this gene in the development of cancer and the description of genetic variations.

Published
2019
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124. Stibnite-gold mineralisations in the Eastern Cordillera of Bolivia: case studies and genetic model.

Author

Lehrberger G., 31st International Geological Congress Rio de Janeiro, Brazil 6-17 Aug. 2000, Mejia L., Lehrberger G., 31st International Geological Congress Rio de Janeiro, Brazil 6-17 Aug. 2000, and Mejia L.

Abstract

An investigation of five Sb-Au deposits, Antofagasta, Santa Rosa de Capasirca and Cebadillas in the north and Candelaria-San Juan and Sucre in the south, has shown that the mineralisation formed during the Palaeozoic as a result of fluid and metal remobilisation and redeposition from Lower Palaeozoic sediments, the process having been driven by heat from magmatic processes in the lower crust. Typical primary structures are stratiform quartz veins, known as mantos, and saddle reefs. During the Tertiary, part of the metal content was remobilised and deposited with newly supplied metals in complex veins. Active hot springs are associated with recently formed stibnite and there is evidence that the metals do not derive primarily from magmatic sources, though such sources cannot be completely excluded for gold. Processes of metal concentration in the sediments included adsorption on clay minerals or Fe oxide/hydroxide colloids, membrane filtration and sulphide fixation. Gold was probably enriched by electrochemical precipitation on sulphide mineral surfaces in a black-shale environment., An investigation of five Sb-Au deposits, Antofagasta, Santa Rosa de Capasirca and Cebadillas in the north and Candelaria-San Juan and Sucre in the south, has shown that the mineralisation formed during the Palaeozoic as a result of fluid and metal remobilisation and redeposition from Lower Palaeozoic sediments, the process having been driven by heat from magmatic processes in the lower crust. Typical primary structures are stratiform quartz veins, known as mantos, and saddle reefs. During the Tertiary, part of the metal content was remobilised and deposited with newly supplied metals in complex veins. Active hot springs are associated with recently formed stibnite and there is evidence that the metals do not derive primarily from magmatic sources, though such sources cannot be completely excluded for gold. Processes of metal concentration in the sediments included adsorption on clay minerals or Fe oxide/hydroxide colloids, membrane filtration and sulphide fixation. Gold was probably enriched by electrochemical precipitation on sulphide mineral surfaces in a black-shale environment.

Published
2000

143. CAT and MRI Studies of Spinal Cord Injured Rats Implanted with PPy/I.

Author

Morales-Guadarrama, A., Salgado-Ceballos, H., Morales, J., Ríos, C., Cruz, G. J., Diaz-Ruiz, A., Olayo, M.-G., Alvarez-Mejia, L., Mondragón-Lozano, R., and Olayo, R.

Subjects
SPINAL cord injuries, MAGNETIC resonance imaging, LABORATORY rats, POLYMERIZATION, BLOOD plasma, PYRROLES, DIAGNOSIS
Abstract

Copyright of Revista Mexicana de Ingeniería Biomédica is the property of Sociedad Mexicana de Ingenieria Biomedica, A.C. and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Published
2013

147. Diversity and distribution of Ralstonia solanacearum strains in Guatemala and rare occurrence of tomato fruit infection.

Author

Perez, A. Sanchez, Mejia, L., Fegan, M., and Allen, C.

Subjects
*BANANA diseases & pests, *BANANAS, *BACTERIAL wilt of potato, *PLANT physiology, *TOMATO diseases & pests, *TOMATO wilts, *PLANT diseases, *SOIL microbiology
Abstract

Fifty-nine Ralstonia solanacearum isolates from diverse crops and regions were collected and characterized to determine the distribution and diversity of this soilborne pathogen in Guatemala. Three distinct types were present: a phylotype I, sequevar 14 strain, probably originating from Asia, infecting tomatoes and aubergines at moderate elevations; a phylotype II, sequevar 6 strain of American origin causing Moko disease in lowland banana plantations; and a phylotype II, sequevar 1 (race 3 biovar 2) strain causing brown rot on potatoes, Southern wilt of Pelargonium spp. and bacterial wilt of greenhouse tomatoes at high elevations. These data on strain diversity will inform effective regional efforts to breed for wilt resistance. A sensitive enrichment method did not detect the pathogen in fruits from naturally infected commercial tomato plants in Guatemalan fields and greenhouses, although it was detected in 6% of fruits from a wilt-resistant hybrid. Low numbers of R. solanacearum cells were also infrequently detected in fruits from plants artificially inoculated in the growth chamber with either race 3 biovar 2 or a phylotype II tomato strain. [ABSTRACT FROM AUTHOR]

Published
2008
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148. DEPENDENCIA DE LA RESPUESTA ÓPTICA CON EL DECAPADO QUÍMICO DE PELÍCULAS DE Ga1-xInxAsySb1-y.

Author

Tirado-Mejia, L., Osorio, J., Segura, J., Ortiz, C., Gutiérrez, N. J., De los Rios, M., Fonthal, G., and Ariza-Calderón, H.

Subjects
*LIQUID phase epitaxy, *EPITAXY, *PHOTOLUMINESCENCE, *SEMICONDUCTOR etching, *OXIDES
Abstract

Gal-xInxAsySbl-y epitaxial films grown by Liquid Phase Epitaxy were etched by using an acid solution during different dipping times. The etching rate was obtained by means of thickness measurements for different wetting times. The optical response and its variation with etching were measured by photoluminescence technique. The differences in the energy position of optical response for the different etching times were associated to the removal of the most superficial oxide layers. We found a good material to cover the substrate surface to obtain the etching rate. [ABSTRACT FROM AUTHOR]

Published
2006

150. Determining the digestible lysine requirement of Cobb MV × Cobb 500 FF broilers from 28-41 days of age and the effect of feeding varying digestible lysine levels on performance, processing, and economics

Author

Dennehy, D.G., Brown, A.T., Coto, C., Mejia, L., and Wamsley, K.G.S.

Abstract

The current objective was to expand on previous research using the Cobb MV × Cobb 500 to determine its finisher digestible Lys (dLys) requirement (Req; d 28-41), as well as the effect of feeding varying finisher dLys levels on performance, processing, and economics. This was a 2 Sex (male or female) × 8 dLys factorial arrangement, wherein the experimental diets consisted of a practical control; (PRAC-CON; 0.94% dLys) and 7 other diets with varying dLys concentrations (0.72%, 0.80%, 0.88%, 0.94%, 1.02%, 1.10%, and 1.18%) Chicks were fed common starter (1.28% dLys) and grower diets (grower 1 and 2 dLys were 1.18 and 1.08%, respectively). In general, males had improved performance vs. females while females had increased processing yield (% of live weight) vs. males. Also, increasing finisher dLys resulted in improvements in performance and processing metrics, regardless of sex. Quadratic regression (QR; 95% of vertex) and linear and quadratic broken line (LBL; QBL) models were utilized to estimate dLys Req for each sex. The estimated dLys Req range for females was 0.752-1.292% and males, 0.748-1.320%, when using all models. An economic model determined 1.10% finisher dLys to be most profitable. These data demonstrate that increasing finisher dLys can improve Cobb MV × Cobb 500 performance and processing; however, the optimal dLys Req can vary depending on sex, regression model, response parameter, and economics.

Published
2022
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