Artículos Científicos

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    Media compositions affects the fatty acids profiles of three oleaginous microalgae from peruvian amazon
    (Asian Journal of Microbiology and Biotechnology, 1(1), 14-24, 2017-01-21) Cobos, Marianela; Lopez, Liz C.; Paredes, Jae D.; Maddox, J. Dylan; Vargas-Arana, Gabriel E.; Flores, Leenin; Aguilar, Carla P.; Castro, Juan C.
    The objective of this research was to determine the effect of four culture media on the fatty acids profile of the microalgae Ankistrodesmus sp., Chlorella sp., and Scenedesmus sp. isolated from the Peruvian Amazon. The microalgae species were growth by triplicate in Beijerinck's medium (BM), Blue Green medium (BG-11), Bold Basal medium (BBM), and CHU-10 medium. Growth was monitored by spectrophotometric analysis at 680 nm. Biomass productivity, biochemical analyzes, and fatty acids profiling were performed using standard methods. The highest growth was obtained with BM, BBM, and CHU-10 medium for the three microalgae species and the biomass productivity was highest (> 0.23 mg.L-1.d-1) in CHU-10 medium. The highest total lipid content was reported with Ankistrodesmus sp. (13.77 - 21.58%). Carbohydrate content varied between 8.46 and 50.17%, with the highest percentage when the microalgae were cultured in BG-11 (27.26 – 37.80%) and CHU-10 media (30.72 – 50.17%). Also, the highest protein content was found in the three microalgae species cultured in BM medium (24.89 - 30.44%). The fatty acids profiles showed differences at the intra-species and inter-species levels. In conclusion, the three microalgae showed differences in their growth profile, biomass productivity, biochemical composition (carbohydrates, total lipids, and proteins contents), and fatty acids profiles. Likewise, these growth and biochemical parameters are markedly affected by the media composition. Additionally, the fatty acids profiles of the three microalgae reveals that are a good feedstocks for biodiesel production.
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    Caracterización in silico y análisis de la expresión de la subunidad alfa de la acetil-coenzima a carboxilasa heteromérica de dos microalgas
    (Universidad Nacional de Colombia, 2019) Castro, Juan C.; Maddox, J. Dylan; Estela, Segundo L.; Rodríguez, Hicler N.; Casuso, María Z.; Paredes, Jae D.; Cobos, Marianela
    Las microalgas son microorganismos fotosintéticos con gran potencial para abastecer las demandas energéticas mundiales. Sin embargo, los limitados conocimientos que se tienen de estos organismos, en particular a nivel molecular de los procesos metabólicos, han limitado su uso con estos propósitos. En esta investigación se ha realizado el análisis in silico de la subunidad alfa de la acetil-Coenzima A carboxilasa heteromérica (αACCasa), una enzima clave en la biosíntesis de lípidos de las microalgas Chlorella sp. y Scenedesmus sp. Asimismo, se ha medido la expresión de este gen en ambas especies cultivadas en medios deficientes de nitrógeno. Los resultados indican que la αACCasa muestra conservación estructural y funcional en ambas especies de microalgas y su mayor similitud genética con otras especies de microalgas. Asimismo, se ha mostrado que el nivel de expresión del gen se incrementa significativamente cuando las microalgas son cultivadas en ausencia de nitrógeno, lo cual se relaciona a su vez con una mayor acumulación de lípidos microalgales. En conclusión, el análisis in silico de la αACCasa de Chlorella sp. y Scenedesmus sp. presentan características estructurales, funcionales y evolutivas muy similares con otras especies de microalgas y plantas. Asimismo, el estudio revela que en ambas especies el gen se sobreexpresa cuando las microalgas son sometidas a estrés por deficiencia de nitrógeno, el cual se relaciona significativamente con la acumulación de lípidos totales en estas células.
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    De novo RNA-Seq analysis of the oleauginous microalgae Ankistrodesmus sp. UCP0001: Gene identification and metabolic pathways reconstruction for the biosynthesis of fatty acids and triacylglycerols
    (Plant Cell Biotechnology and Molecular Biology 18(5-6): 219-230, 2017-05-15) Castro, Juan C.; Maddox, J. Dylan; Paredes, Jae D.; Rodríguez, Hicler N.; Aguilar, Carla P.; Marapara, Jorge L.; Castro, Carlos G.; Casuso, María Z.; Cobos, Marianela
    Microalgae have great potential as feedstock to produce next-generation biofuels. The scarceness of genomic level information, however, prevents the rational de novo microalgae strain design. In this research, we describe the next-generation sequencing, de novo assembly, and functional annotation of the transcriptome of Ankistrodesmus sp. UCP0001. In total 48,867,830 high-quality sequence reads were de novo assembled into 38,414 unigenes (mean length = 508 bp, N50 = 1038 bp). Seventy-two percent of unigenes presented mapping information. Based on the KEGG pathway assignment, the fatty acids and the triacylglycerol biosynthesis pathways were reconstructed. Our results demonstrate that the synergy among high-throughput sequencing technologies and appropriate bioinformatics tools provides a fast, low-cost, and effective approach to generate invaluable functional genomic information in non-model microalgae species (e.g., Ankistrodesmus sp.). With the de novo assembled and annotated transcriptome we have successfully identified genes encoding enzymes and reconstructed metabolic pathways for the biosynthesis of fatty acids and triacylglycerols in this microalgae species. This genetic information could be used for the de novo microalgae strain design with desirable characteristics to produce biodiesel and capabilities for the biosynthesis of others valuable bioactive compounds of interest to the pharmacological, food, and cosmetic industries.
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    Plasma Tryptophan and the Kynurenine-Tryptophan Ratio are Associated with the Acquisition of Statural Growth Deficits and Oral Vaccine Underperformance in Populations with Environmental Enteropathy.
    (The American Journal of Tropical Medicin and Hygiene, 2016-10-05) Kosek, Margaret N.; Mduma, Estomih; Kosek, Peter S.; Lee, Gwenyth O.; Svensen, Erling; K. Y. Pan, William; Paredes Olortegui, Maribel; H. Bream, Jay; Patil, Crystal; Ramal Asayag, Cesar; Meza Sanchez, Graciela; E. Caulfield, Laura; Gratz, Jean; Peñataro Yori, Pablo
    Early childhood enteric infections have adverse impacts on child growth and can inhibit normal mucosal responses to oral vaccines, two critical components of environmental enteropathy. To evaluate the role of indoleamine 2,3-dioxygenase 1 (IDO1) activity and its relationship with these outcomes, we measured tryptophan and the kynurenine–tryptophan ratio (KTR) in two longitudinal birth cohorts with a high prevalence of stunting. Children in rural Peru and Tanzania (N = 494) contributed 1,251 plasma samples at 3, 7, 15, and 24 months of age and monthly anthropometrics from 0 to 36 months of age. Tryptophan concentrations were directly associated with linear growth from 1 to 8 months after biomarker assessment. A 1-SD increase in tryptophan concentration was associated with a gain in length-for-age Z-score (LAZ) of 0.17 over the next 6 months in Peru (95% confidence interval [CI] = 0.11–0.23, P < 0.001) and a gain in LAZ of 0.13 Z-scores in Tanzania (95% CI = 0.03–0.22, P = 0.009). Vaccine responsiveness data were available for Peru only. An increase in kynurenine by 1 μM was associated with a 1.63 (95% CI = 1.13–2.34) increase in the odds of failure to poliovirus type 1, but there was no association with tetanus vaccine response. A KTR of 52 was 76% sensitive and 50% specific in predicting failure of response to serotype 1 of the oral polio vaccine. KTR was associated with systemic markers of inflammation, but also interleukin-10, supporting the association between IDO1 activity and immunotolerance. These results strongly suggest that the activity of IDO1 is implicated in the pathophysiology of environmental enteropathy, and demonstrates the utility of tryptophan and kynurenine as biomarkers for this syndrome, particularly in identifying those at risk for hyporesponsivity to oral vaccines.
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    A simple and efficient method for high-quality total RNA isolation from oleaginous microalgae
    (Plant Cell Biotechnology and Molecular Biology, 18(1-2), 15-21, 2017-01-06) Castro, Juan C.; Rodríguez, Hicler N.; Maddox, J. Dylan; Jiu, Bruce; Petterman, Joe B.; Marapara, Jorge L.; Cobos, Marianela
    Microalgae are a very diverse group of microorganisms with great potential for biotechnological applications. To best exploit these organisms is necessary to expand our knowledge at its molecular levels. To realize these studies, however, it is essential to have efficient and reproducible methods for total RNA isolation. The objective of this research was to develop a method for high-quality total RNA isolation from three oleaginous microalgae species promissories for biotechnological applications. Three strains Ankistrodesmus sp., Chlorella sp., and Scenedesmus sp. were cultured on CHU-10 medium. Then, were harvested by centrifugation and total RNA was isolated with three commercial kits, one previously published method, and our improved CTAB-LiCl method. Quality and quantity of total RNA isolated were assayed with standard spectrophotometric and electrophoretic techniques. The highest quality (A260/A280: 1.95-2.02, A260/A230: 1.12-1.84) and yield (16.40-93.63 mg/g fresh weight) of total RNA from the three microalgae strains were obtained with our improved CTAB-LiCl method. In addition, the time required to complete the isolation process and the cost were relatively lowest. In conclusion, the improved CTAB-LiCl method, in contrast to frequently used commercial kits, and a previously published method, is effective and reliable to produce total RNA of high quality and quantity that is suitable for cDNA synthesis and polymerase chain reaction.