Browsing by Author "Cerda, Ariel"

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    An Open One-Step RT-qPCR for SARS-CoV-2 detection
    (2024) Cerda, Ariel; Rivera, Maira; Armijo, Grace; Ibarra-Henriquez, Catalina; Reyes, Javiera; Blazquez-Sanchez, Paula; Aviles, Javiera; Arce, Anibal; Seguel, Aldo; Brown, Alexander J.; Vasquez, Yesseny; Cortez-San Martin, Marcelo; Cubillos, Francisco A.; Garcia, Patricia; Ferres, Marcela; Ramirez-Sarmiento, Cesar A.; Federici, Fernan; Gutierrez, Rodrigo A.
    The COVID-19 pandemic has resulted in millions of deaths globally, and while several diagnostic systems were proposed, real-time reverse transcription polymerase chain reaction (RT-PCR) remains the gold standard. However, diagnostic reagents, including enzymes used in RT-PCR, are subject to centralized production models and intellectual property restrictions, which present a challenge for less developed countries. With the aim of generating a standardized One-Step open RT-qPCR protocol to detect SARS-CoV-2 RNA in clinical samples, we purified and tested recombinant enzymes and a non-proprietary buffer. The protocol utilized M-MLV RT and Taq DNA pol enzymes to perform a Taqman probe-based assay. Synthetic RNA samples were used to validate the One-Step RT-qPCR components, demonstrating sensitivity comparable to a commercial kit routinely employed in clinical settings for patient diagnosis. Further evaluation on 40 clinical samples (20 positive and 20 negative) confirmed its comparable diagnostic accuracy. This study represents a proof of concept for an open approach to developing diagnostic kits for viral infections and diseases, which could provide a cost-effective and accessible solution for less developed countries.
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    Loop assembly: a simple and open system for recursive fabrication of DNA circuit
    (2019) Pollak, Bernardo; Cerda, Ariel; Delmans, Mihails; Álamos, Simón; Moyano, Tomás; West, Anthony; Gutiérrez, Rodrigo A.; Patron, Nicola J.; Federici, Fernán; Haseloff, Jim
    High-efficiency methods for DNA assembly have enabled the routine assembly of syntheticDNAs of increased size and complexity. However, these techniques require customization,elaborate vector sets or serial manipulations for the different stages of assembly. We have developed Loop assembly based on a recursive approach to DNA fabrication. Thesystem makes use of two Type IIS restriction endonucleases and corresponding vector sets forefficient and parallel assembly of large DNA circuits. Standardized level 0 parts can be assem-bled into circuits containing 1, 4, 16 or more genes by looping between the two vector sets.The vectors also contain modular sites for hybrid assembly using sequence overlap methods. Loop assembly enables efficient and versatile DNA fabrication for plant transformation. Weshow the construction of plasmids up to 16 genes and 38 kb with high efficiency (> 80%).We have characterized Loop assembly on over 200 different DNA constructs and validatedthe fidelity of the method by high-throughput Illumina plasmid sequencing. Our method provides a simple generalized solution for DNA construction with standardizedparts. The cloning system is provided under an OpenMTA license for unrestricted sharing andopen access.