Uridylation of miRNAs by HEN1 SUPPRESSOR1 in \u3ci\u3eArabidopsis\u3c/i\u3e

HEN1-mediated 2′-O-methylation has been shown to be a key mechanism to protect plant microRNAs (miRNAs) and small interfering RNAs (siRNAs) as well as animal piwi-interacting RNAs (piRNAs) from degradation and 3′ terminal uridylation [1–8]. However, enzymes uridylating unmethylated miRNAs, siRNAs, or piRNAs in hen1 are unknown. In this study, a genetic screen identified a second-site mutation hen1 suppressor1-2 (heso1-2) that partially suppresses the morphological phenotypes of the hypomorphic hen1-2 allele and the null hen1-1 allele in Arabidopsis. HESO1 encodes a terminal nucleotidyl transferase that prefers to add untemplated uridine to the 3′ end of RNA, which is completely abolished by 2′-O-methylation. heso1-2 affects the profile of u-tailed miRNAs and siRNAs and increases the abundance of truncated and/or normal sized ones in hen1, which often results in increased total amount of miRNAs and siRNAs in hen1. In contrast, overexpressing HESO1 in hen1-2 causes more severe morphological defects and less accumulation of miRNAs. These results demonstrate that HESO1 is an enzyme uridylating unmethylated miRNAs and siRNAs in hen1. These observations also suggest that uridylation may destabilize unmethylated miRNAs through an unknown mechanism and compete with 3′-to-5′ exoribonuclease activities in hen1. This study shall have implications on piRNA uridylation in hen1 in animals

Small RNAs meet their targets: When methylation defends miRNAs from uridylation

Small RNAs are incorporated into Argonaute protein-containing complexes to guide the silencing of target RNAs in both animals and plants. The abundance of endogenous small RNAs is precisely controlled at multiple levels including transcription, processing and Argonaute loading. In addition to these processes, 3\u27 end modification of small RNAs, the topic of a research area that has rapidly evolved over the last several years, adds another layer of regulation of their abundance, diversity and function. Here, we review our recent understanding of small RNA 3\u27 end methylation and tailing

An adaptive observer-based parameter estimation algorithm with application to road gradient and vehicle's mass estimation

A novel observer-based parameter estimation algorithm with sliding mode term has been developed to estimate the road gradient and vehicle weight using only the vehicle's velocity and the driving torque from the engine. The estimation algorithm exploits all known terms in the system dynamics and a low pass filtered representation to derive an explicit expression of the parameter estimation error without measuring the acceleration. The proposed algorithm which features a sliding-mode term to ensure the fast and robust convergence of the estimation in the presence of persistent excitation is augmented to an adaptive observer and analyzed using Lyapunov Theory. The analytical results show that the algorithm is stable and ensures finite-time error convergence to a bounded error even in the presence of disturbances. A simple practical method for validating persistent excitation is provided using the new theoretical approach to estimation. This is validated by the practical implementation of the algorithm on a small-scaled vehicle, emulating a car system. The slope gradient as well as the vehicle's mass/weight are estimated online. The algorithm shows a significant improvement over a previous result

Study on the Status and Influencing Factors of First Aid Knowledge and Skills of Community Residents

To analyze the current situation of first aid knowledge and skills of community residents in Yibin City and related influencing factors, and to explore effective ways to improve the knowledge and skills of community residents in Yibin City. A questionnaire survey was conducted with a convenience sample of 589 community residents in Yibin city. The first aid questionnaire designed by Li Li was used to investigate the knowledge of seven aspects, including first aid telephone, cardiac and respiratory arrest, trauma, accidental injury, common emergencies and other first aid. The score of first aid knowledge was (35.2±6.9), and the pass rate was 72.84%. It was found that there were statistical differences in the total pass rate of first aid knowledge and skills among community residents with different genders, ages, occupations, training experiences, and text studies, but there was no statistical difference in the total pass rate of first aid knowledge and skills among community residents with different health conditions and different first aid experiences. Community residents who were female, 18-25 years old, medical personnel/medical students, had training experience, and had obtained a first aid certificate had the highest pass rates and the best first aid knowledge and skills