Highly specific gene silencing in a monocot species by artificial microRNAs derived from chimeric miRNA precursors.

Artificial microRNAs (amiRNAs) are used for selective gene silencing in plants. However, current methods to produce amiRNA constructs for silencing transcripts in monocot species are not suitable for simple, cost-effective and large-scale synthesis. Here, a series of expression vectors based on Oryza sativa MIR390 (OsMIR390) precursor was developed for high-throughput cloning and high expression of amiRNAs in monocots. Four different amiRNA sequences designed to target specifically endogenous genes and expressed from OsMIR390-based vectors were validated in transgenic Brachypodium distachyon plants. Surprisingly, amiRNAs accumulated to higher levels and were processed more accurately when expressed from chimeric OsMIR390-based precursors that include distal stem-loop sequences from Arabidopsis thaliana MIR390a (AtMIR390a). In all cases, transgenic plants displayed the predicted phenotypes induced by target gene repression, and accumulated high levels of amiRNAs and low levels of the corresponding target transcripts. Genome-wide transcriptome profiling combined with 5'-RLM-RACE analysis in transgenic plants confirmed that amiRNAs were highly specific.

What's in a Name? Report of the ACR Task Force on General Radiology and Multi-Subspecialization.

The ACR Council passed Resolution 47 at its 2020 annual meeting establishing a representative task force (TF) to explore the concept of the "multispecialty radiologist," previously proposed in 2012. The TF held eight virtual meetings over 8 months, considered data from a 2020 ACR Membership Tracking Survey, conducted a review of current literature, and collected anecdotal experience from TF members and ACR leadership. ACR legal counsel and a cross-section of ACR Commissions and Committees also provided input. The TF concluded that there is scant interest from the radiology community in the multispecialty radiologist title and no agreed-upon definition for the term. Radiologists may identify as diagnostic or subspecialty radiologists; however, the roles they fill in clinical practice include general, multispecialty, and subspecialized radiology. The TF proposes definitions for each of these terms to support radiologist recruitment aligned with optimal patient care in the practice community and to improve the quality of data collection about the field. To reduce ambiguity, the TF proposes adoption of the defined terms by the radiology community, including radiologist recruiters and employers, and suggests ways in which resident training and the ABR board examination can be adapted to support this new structure. Additionally, as part of an exploration of hyperspecialization and trainee preparedness for clinical practice, the TF discussed the challenges faced by community-based practices seeking to provide a full range of high-quality, radiologist-delivered diagnostic and interventional services to their patient populations.

Swimmer's CT: improved imaging of the lower neck and thoracic inlet.

CT findings of the base of the neck are often degraded by beam-hardening artifact from the shoulder girdle. This artifact can be reduced by placing the patient in a "swimmer's" position, a supine position in which the patient has one arm fully abducted and the other arm lowered. We selectively employed swimmer's CT in patients between January 1999 and December 2002 when standard (arms-down) CT failed to depict suspected disease. In nine of 10 patients, swimmer's CT improved CT quality or accuracy or both over that obtained when the standard CT position was used.

Fed-batch two-phase production of alanine by a metabolically engineered Escherichia coli.

DL-Alanine was produced from glucose in an Escherichia coli pfl pps poxB ldhA aceEF pTrc99A-alaD strain which lacked pyruvate-formate lyase, phosphoenolpyruvate (PEP) synthase, pyruvate oxidase, lactate dehydogenase, components of the pyruvate dehydogenase complex and over-produced alanine dehydrogenase (ALD). A two-phase process was developed with cell growth under aerobic conditions followed by alanine production under anaerobic conditions. Using the batch mode, cells grew to 5.3 g/l in 9 h with the accumulation of 6-10 g acetate/l, and under subsequent anaerobic conditions achieved 34 g alanine/l in 13 h with a yield of 0.86 g/g glucose. Using the fed-batch mode at micro = 0.15 h(-1), only about 1 g acetate/l formed in the 25 h required for the cells to reach 5.6 g/l, and 88 g alanine/l accumulated during the subsequent 23 h. This fed-batch process attained an alanine volumetric productivity of 4 g/lh during the production phase, and a yield that was essentially 1 g/g.