A quantitative autonomous bioluminescence reporter system with a wide dynamic range for Plant Synthetic Biology.

Plant Synthetic Biology aims to enhance the capacities of plants by designing and integrating synthetic gene circuits (SGCs). Quantitative reporting solutions that can produce quick, rich datasets affordably are necessary for SGC optimization. In this paper, we present a new, low-cost, and high-throughput reporter system for the quantitative measurement of gene expression in plants based on autonomous bioluminescence. This method eliminates the need for an exogenous supply of luciferase substrate by exploiting the entire Neonothopanus nambi fungal bioluminescence cyclic pathway to build a self-sustained reporter. The HispS gene, the pathway's limiting step, was set up as the reporter's transcriptional entry point as part of the new system's design, which significantly improved the output's dynamic range and brought it on par with that of the gold standard FLuc/RLuc reporter. Additionally, transient ratiometric measurements in N. benthamiana were made possible by the addition of an enhanced GFP as a normalizer. The performance of new NeoLuc/eGFP system was extensively validated with SGCs previously described, including phytohormone and optogenetic sensors. Furthermore, we employed NeoLuc/eGFP in the optimization of challenging SGCs, including new configurations for an agrochemical (copper) switch, a new blue optogenetic sensor, and a dual copper/red-light switch for tight regulation of metabolic pathways.

GB_SynP: A Modular dCas9-Regulated Synthetic Promoter Collection for Fine-Tuned Recombinant Gene Expression in Plants.

Programmable transcriptional factors based on the CRISPR architecture are becoming commonly used in plants for endogenous gene regulation. In plants, a potent CRISPR tool for gene induction is the so-called dCasEV2.1 activation system, which has shown remarkable genome-wide specificity combined with a strong activation capacity. To explore the ability of dCasEV2.1 to act as a transactivator for orthogonal synthetic promoters, a collection of DNA parts was created (GB_SynP) for combinatorial synthetic promoter building. The collection includes (i) minimal promoter parts with the TATA box and 5'UTR regions, (ii) proximal parts containing single or multiple copies of the target sequence for the gRNA, thus functioning as regulatory cis boxes, and (iii) sequence-randomized distal parts that ensure the adequate length of the resulting promoter. A total of 35 promoters were assembled using the GB_SynP collection, showing in all cases minimal background and predictable activation levels depending on the proximal parts used. GB_SynP was also employed in a combinatorial expression analysis of an autoluminescence pathway in Nicotiana benthamiana, showing the value of this tool in extracting important biological information such as the determination of the limiting steps in an enzymatic pathway.

Strong and tunable anti-CRISPR/Cas activities in plants.

CRISPR/Cas has revolutionized genome engineering in plants. However, the use of anti-CRISPR proteins as tools to prevent CRISPR/Cas-mediated gene editing and gene activation in plants has not been explored yet. This study describes the characterization of two anti-CRISPR proteins, AcrIIA4 and AcrVA1, in Nicotiana benthamiana. Our results demonstrate that AcrIIA4 prevents site-directed mutagenesis in leaves when transiently co-expressed with CRISPR/Cas9. In a similar way, AcrVA1 is able to prevent CRISPR/Cas12a-mediated gene editing. Moreover, using a N. benthamiana line constitutively expressing Cas9, we show that the viral delivery of AcrIIA4 using Tobacco etch virus is able to completely abolish the high editing levels obtained when the guide RNA is delivered with a virus, in this case Potato virus X. We also show that AcrIIA4 and AcrVA1 repress CRISPR/dCas-based transcriptional activation of reporter genes. In the case of AcrIIA4, this repression occurs in a highly efficient, dose-dependent manner. Furthermore, the fusion of an auxin degron to AcrIIA4 results in auxin-regulated activation of a downstream reporter gene. The strong anti-Cas activity of AcrIIA4 and AcrVA1 reported here opens new possibilities for customized control of gene editing and gene expression in plants.

External Validation of the Rotterdam Computed Tomography Score in the Prediction of Mortality in Severe Traumatic Brain Injury.

INTRODUCTION: Traumatic brain injury (TBI) is a public health problem. It is a pathology that causes significant mortality and disability in Colombia. Different calculators and prognostic models have been developed to predict the neurological outcomes of these patients. The Rotterdam computed tomography (CT) score was developed for prognostic purposes in TBI. We aimed to examine the accuracy of the prognostic discrimination and prediction of mortality of the Rotterdam CT score in a cohort of trauma patients with severe TBI in a university hospital in Colombia. MATERIALS AND METHODS: We analyzed 127 patients with severe TBI treated in a regional trauma center in Colombia over a 2-year period. Bivariate and multivariate analyses were used. The discriminatory power of the score, its accuracy, and precision were assessed by logistic regression and as the area under the receiver operating characteristic curve. Shapiro-Wilk, Chi-square, and Wilcoxon tests were used to compare the real outcomes in the cohort against the predicted outcomes. RESULTS: The median age of the patient cohort was 33 years, and 84.25% were male. The median injury severity score was 25, the median Glasgow Coma Scale motor score was 3, the basal cisterns were closed in 46.46% of the patients, and a midline shift of >5 mm was seen in 50.39%. The 6-month mortality was 29.13%, and the Rotterdam CT score predicted a mortality of 26% (P < 0.0001) (area under the curve: 0.825; 95% confidence interval: 0.745-0.903). CONCLUSIONS: The Rotterdam CT score predicted mortality at 6 months in patients with severe head trauma in a university hospital in Colombia. The Rotterdam CT score is useful for predicting early death and the prognosis of patients with TBI.