Person: Guevara Acosta, Flor Govinda
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First Name
Flor Govinda
Last Name
Guevara Acosta
Affiliation
Universidad Complutense de Madrid
Faculty / Institute
Ciencias Biológicas
Department
Bioquímica y Biología Molecular
Area
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7 results
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Now showing 1 - 7 of 7
- Project number: 140
Item Estrategias de flipped learning en fundamentos de ingeniería genética(2019) Navarro Llorens, Juana María; Lorente Pérez, María del Mar; Sánchez Torralba, Antonio; Blázquez Ortiz, Cristina; Ranz Valdecasa, María Regina; López Conejo, María Teresa; Guevara Acosta, Flor GovindaLa asignatura de Fundamentos de Ingeniería genética del grado de Biología resulta muy árida en su actual formulación. Este proyecto pretende darle la vuelta para que sea el alumno quien construya el conocimiento y participe en el aprendizaje. Item New insights into the genome of Rhodococcus ruber strain Chol-4(BMC Genomics, 2019) Guevara Acosta, Flor Govinda; Castillo López, María; Alonso, Sergio; Perera González, Julián; Navarro Llorens, Juana MaríaBackground: Rhodococcus ruber strain Chol-4, a strain isolated from a sewage sludge sample, is able to grow in minimal medium supplemented with several compounds, showing a broad catabolic capacity. We have previously determined its genome sequence but a more comprehensive study of their metabolic capacities was necessary to fully unravel its potential for biotechnological applications. Results: In this work, the genome of R. ruber strain Chol-4 has been re-sequenced, revised, annotated and compared to other bacterial genomes in order to investigate the metabolic capabilities of this microorganism. The analysis of the data suggests that R. ruber Chol-4 contains several putative metabolic clusters of biotechnological interest, particularly those involved on steroid and aromatic compounds catabolism. To demonstrate some of its putative metabolic abilities, R. ruber has been cultured in minimal media containing compounds belonging to several of the predicted metabolic pathways. Moreover, mutants were built to test the naphtalen and protocatechuate predicted catabolic gene clusters. Conclusions: The genomic analysis and experimental data presented in this work confirm the metabolic potential of R. ruber strain Chol-4. This strain is an interesting model bacterium due to its biodegradation capabilities. The results obtained in this work will facilitate the application of this strain as a biotechnological tool.Item SEVA-Cpf1, a CRISPR-Cas12a vector for genome editing in cyanobacteria(Microbial Cell Factories, 2022) Baldanta Callejo, Sara; Guevara Acosta, Flor Govinda; Navarro Llorens, Juana MaríaBackground Cyanobacteria are photosynthetic autotrophs that have tremendous potential for fundamental research and industrial applications due to their high metabolic plasticity and ability to grow using CO2 and sunlight. CRISPR technology using Cas9 and Cpf1 has been applied to different cyanobacteria for genome manipulations and metabolic engineering. Despite significant advances with genome editing in several cyanobacteria strains, the lack of proper genetic toolboxes is still a limiting factor compared to other model laboratory species. Among the limitations, it is essential to have versatile plasmids that could ease the benchwork when using CRISPR technology. Results In the present study, several CRISPR-Cpf1 vectors were developed for genetic manipulations in cyanobacteria using SEVA plasmids. SEVA collection is based on modular vectors that enable the exchangeability of diverse elements (e.g. origins of replication and antibiotic selection markers) and the combination with many cargo sequences for varied end-applications. Firstly, using SEVA vectors containing the broad host range RSF1010 origin we demonstrated that these vectors are replicative not only in model cyanobacteria but also in a new cyanobacterium specie, Chroococcidiopsis sp., which is different from those previously published. Then, we constructed SEVA vectors by harbouring CRISPR elements and showed that they can be easily assimilated not only by conjugation, but also by natural transformation. Finally, we used our SEVA-Cpf1 tools to delete the nblA gene in Synechocystis sp. PCC 6803, demonstrating that our plasmids can be applied for CRISPR-based genome editing technology. Conclusions The results of this study provide new CRISPR-based vectors based on the SEVA (Standard European Vector Architecture) collection that can improve editing processes using the Cpf1 nuclease in cyanobacteria.Item Metabolic engineering of Rhodococcus ruber Chol-4: A cell factory for testosterone production(Plos One, 2019) Guevara Acosta, Flor Govinda; Olortegui Flores, Yamileth; Fernández de las Heras, Laura; Perera González, Julián; Navarro Llorens, Juana MaríaRhodococcus ruber Chol-4 is a potent steroid degrader that has a great potential as a biotechnological tool. As proof of concept, this work presents testosterone production from 4- androstene-3,17-dione by tailoring innate catabolic enzymes of the steroid catabolism inside the strain. A R. ruber quadruple mutant was constructed in order to avoid the breakage of the steroid nucleus. At the same time, an inducible expression vector for this strain was developed. The 17-ketoreductase gene from the fungus Cochliobolus lunatus was cloned and overexpressed in this vector. The engineered strain was able to produce testosterone from 4-androstene-3,17-dione using glucose for cofactor regeneration with a molar conversion of 61%. It is important to note that 91% of the testosterone was secreted outside the cell after 3 days of cell biotransformation. The results support the idea that Rhodococcus ruber Chol-4 can be metabolically engineered and can be used for the production of steroid intermediates.Item Further Studies on the 3-Ketosteroid 9α-Hydroxylase of Rhodococcus ruber Chol-4, a Rieske Oxygenase of the Steroid Degradation Pathway(Microorganisms, 2021) Baldanta Callejo, Sara; Navarro Llorens, Juana María; Guevara Acosta, Flor GovindaThe biochemistry and genetics of the bacterial steroid catabolism have been extensively studied during the last years and their findings have been essential to the development of biotechnological applications. For instance, metabolic engineering of the steroid-eater strains has allowed to obtain intermediaries of industrial value. However, there are still some drawbacks that must be overcome, such as the redundancy of the steroid catabolism genes in the genome and a better knowledge of its genetic regulation. KshABs and KstDs are key enzymes involved in the aerobic breakage of the steroid nucleus. Rhodococcus ruber Chol-4 contains three kshAs genes, a single kshB gene and three kstDs genes within its genome. In the present work, the growth of R. ruber ΔkshA strains was evaluated on different steroids substrates; the promoter regions of these genes were analyzed; and their expression was followed by qRT-PCR in both wild type and ksh mutants. Additionally, the transcription level of the kstDs genes was studied in the ksh mutants. The results show that KshA2B and KshA1B are involved in AD metabolism, while KshA3B and KshA1B contribute to the cholesterol metabolism in R. ruber. In the kshA single mutants, expression of the remaining kshA and kstD genes is re-organized to survive on the steroid substrate. These data give insight into the fine regulation of steroid genes when several isoforms are present.Item First characterization of cultivable extremophile Chroococcidiopsis isolates from a solar panel(Frontiers in Microbiology, 2023) Baldanta Callejo, Sara; Arnal, Raquel; Blanco-Rivero, Amaya; Guevara Acosta, Flor Govinda; Navarro Llorens, Juana MaríaIntroduction: Microorganisms colonize a wide range of natural and artificial environments. Even though most of them are unculturable in laboratory conditions, some ecosystems are ideal niches for bioprospecting extremophiles with unique properties. Up today, there are few reports concerning microbial communities found on solar panels, a widespread, artificial, extreme habitat. Microorganisms found in this habitat belong to drought-, heat- and radiation-adapted genera, including fungi, bacteria, and cyanobacteria. Methods: Here we isolated and identified several cyanobacteria from a solar panel. Then, some strains isolated were characterizated for their resistance to desiccation, UV-C exposition, and their growth on a range of temperature, pH, NaCl concentration or diverse carbon and nitrogen sources. Finally, gene transfer to these isolates was evaluated using several SEVA plasmids with different replicons to assess their potential in biotechnological applications. Results and discussion: This study presents the first identification and characterization of cultivable extremophile cyanobacteria from a solar panel in Valencia, Spain. The isolates are members of the genera Chroococcidiopsis, Leptolyngbya, Myxacorys, and Oculatella all genera with species commonly isolated from deserts and arid regions. Four of the isolates were selected, all of them Chroococcidiopsis, and characterized. Our results showed that all Chroococcidiopsis isolates chosen were resistant up to a year of desiccation, viable after exposition to high doses of UV-C, and capable of being transformed. Our findings revealed that a solar panel is a useful ecological niche in searching for extremophilic cyanobacteria to further study the desiccation and UV-tolerance mechanisms. We conclude that these cyanobacteria can be modified and exploited as candidates for biotechnological purposes, including astrobiology applications.Item Characterization of Limnospira platensis PCC 9108 R-M and CRISPR-Cas systems(Microbiological Research, 2023) Castillo López, María; Guevara Acosta, Flor Govinda; Baldanta Callejo, Sara; Suárez Rodríguez, Patricia; Agudo, Lucía; Nogales, Juan; Díaz Carrasco, Asunción; Arribas-Aguilar, Fernando; Pérez-Pérez, Julián; García, Jose Luis; Galán, Beatriz; Navarro Llorens, Juana MaríaThe filamentous cyanobacterium Limnospira platensis, formerly known as Arthrospira platensis or spirulina, is one of the most commercially important species of microalgae. Due to its high nutritional value, pharmacological and industrial applications it is extensively cultivated on a large commercial scale. Despite its widespread use, its precise manipulation is still under development due to the lack of effective genetic protocols. Genetic transformation of Limnospira has been attempted but the methods reported have not been generally reproducible in other laboratories. Knowledge of the transformation defense mechanisms is essential for understanding its physiology and for broadening their applications. With the aim to understand more about the genetic defenses of L. platensis, in this work we have identified the restriction-modification and CRISPR-Cas systems and we have cloned and characterized thirteen methylases. In parallel, we have also characterized the methylome and orphan methyltransferases using genome-wide analysis of DNA methylation patterns and RNA-seq. The identification and characterization of these enzymes will be a valuable resource to know how this strain avoids being genetically manipulated and for further genomics studies.