Publications by authors named "Levi Lowder"

Background: Few studies have investigated optimal storage conditions or expiration dates for sublingual immunotherapy (SLIT) formulations prepared from glycerinated allergen extracts.

Hypothesis/objectives: The objective of this study was to compare concentrations of short ragweed major allergen (Amb a 1) and total protein in SLIT formulations stored at two different temperatures. It was hypothesised that protein concentrations would show greater decline over time in a formulation stored at room temperature (RT) than in one stored under refrigeration.

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The first report presenting successful and efficient carrot genome editing using CRISPR/Cas9 system. Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR)/CRISPR-associated (Cas9) is a powerful genome editing tool that has been widely adopted in model organisms recently, but has not been used in carrot-a model species for in vitro culture studies and an important health-promoting crop grown worldwide. In this study, for the first time, we report application of the CRISPR/Cas9 system for efficient targeted mutagenesis of the carrot genome.

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User-friendly tools for robust transcriptional activation of endogenous genes are highly demanded in plants. We previously showed that a dCas9-VP64 system consisting of the deactivated CRISPR-associated protein 9 (dCas9) fused with four tandem repeats of the transcriptional activator VP16 (VP64) could be used for transcriptional activation of endogenous genes in plants. In this study, we developed a second generation of vector systems for enhanced transcriptional activation in plants.

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Besides genome editing, the CRISPR-Cas9-based platform provides a new way of engineering artificial transcription factors (ATFs). Multiplex of guide RNA (gRNA) expression cassettes holds a great promise for many useful applications of CRISPR-Cas9. In this chapter, we provide a detailed protocol for building advanced multiplexed CRISPR-dCas9-Activator/repressor T-DNA vectors for carrying out transcriptional activation or repression experiments in plants.

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Novel tools and methods for regulating in vivo plant gene expression are quickly gaining popularity and utility due to recent advances in CRISPR-dCas9 chimeric effector regulators, otherwise known as CRISPR artificial transcription factors (CRISPR-ATFs). These tools are especially useful for studying gene function and interaction within various regulatory networks. First generation CRISPR-ATFs are nuclease-deactivated (dCas9) CRISPR systems where dCas9 proteins are fused to known transcriptional activator domains (VP64) or repressor domains (SRDX).

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Genome editing promises giant leaps forward in advancing biotechnology, agriculture, and basic research. The process relies on the use of sequence specific nucleases (SSNs) to make DNA double stranded breaks at user defined genomic loci, which are subsequently repaired by two main DNA repair pathways: non-homologous end joining (NHEJ) and homology directed repair (HDR). NHEJ can result in frameshift mutations that often create genetic knockouts.

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Multiplex CRISPR-Cas9 nuclease mediated genome editing is an efficient method for disrupting gene function in plants. Use of CRISPR-Cas9 has escalated rapidly in recent years and is expected to become routine practice in molecular biology and related fields of research. Due to the relatively novel and widespread adoption of this technology, first-time users may not have regular access to experienced guidance or technical support from peers or mentors.

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Clustered regularly interspaced short palindromic repeats (CRISPR)-Cpf1 has emerged as an effective genome editing tool in animals. Here we compare the activity of Cpf1 from Acidaminococcus sp. BV3L6 (As) and Lachnospiraceae bacterium ND2006 (Lb) in plants, using a dual RNA polymerase II promoter expression system.

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Advanced CRISPR-Cas9 based technologies first validated in mammalian cell systems are quickly being adapted for use in plants. These new technologies increase CRISPR-Cas9's utility and effectiveness by diversifying cellular capabilities through expression construct system evolution and enzyme orthogonality, as well as enhanced efficiency through delivery and expression mechanisms. Here, we review the current state of advanced CRISPR-Cas9 and Cpf1 capabilities in plants and cover the rapid evolution of these tools from first generation inducers of double strand breaks for basic genetic manipulations to second and third generation multiplexed systems with myriad functionalities, capabilities, and specialized applications.

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The relative ease, speed, and biological scope of clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated Protein9 (Cas9)-based reagents for genomic manipulations are revolutionizing virtually all areas of molecular biosciences, including functional genomics, genetics, applied biomedical research, and agricultural biotechnology. In plant systems, however, a number of hurdles currently exist that limit this technology from reaching its full potential. For example, significant plant molecular biology expertise and effort is still required to generate functional expression constructs that allow simultaneous editing, and especially transcriptional regulation, of multiple different genomic loci or multiplexing, which is a significant advantage of CRISPR/Cas9 versus other genome-editing systems.

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