Light is the most influential environmental stimulus for plant growth. In response to deficient light, plants reprogram their development to adjust their growth in search for a light source. A fine reprogramming of gene expression orchestrates this adaptive trait. Here we show that plants alter microRNA (miRNA) biogenesis in response to light transition. When plants suffer an unusual extended period of light deprivation, the miRNA biogenesis factor HYPONASTIC LEAVES 1 (HYL1) is degraded but an inactive pool of phosphorylated protein remains stable inside the nucleus. Degradation of HYL1 leads to the release of gene silencing, triggering a proper response to dark and shade. Upon light restoration, a quick dephosphorylation of HYL1 leads to the reactivation of miRNA biogenesis and a switch toward a developmental program that maximizes the light uptake. Our findings define a unique and fast regulatory mechanism controlling the plant silencing machinery during plant light response.

During the de-etiolation process, light triggers the accumulation of the core microprocessor components and pri-miRNAs, but not miRNAs. Light-induced suppression of DCL1 activity and SDN1-induction modulate this phenomenon, called miRNA-biogenetic inconsistency, and that is essential for the survival of de-etiolated seedlings after long-term skotomorphogenesis.

accelerated by the readily-available hardware platforms, as well as This paper presents the design principles, implementation, and core system software such as sensor node operating systems in evaluation of the RETOS operating system which is specifically particular. From the early days, much effort has been given to developed for micro sensor nodes. RETOS has four distinct develop efficient and yet complete operating systems for micro objectives, which are to provide (1) a multithreaded programming sensor nodes. For instance, TinyOS [1] has historically been used by interface, (2) system resiliency, (3) kerel extensibility with many practitioners in the field and even advocated as "the" dynamic reconfiguration, and (4) WSN-oriented network operating system for WSN. Other operating systems such as abstraction. RETOS is a multithreaded operating system, hence it SOS[2], Contiki[3], MANTIS[4], and t-kernel[5] have challenged provides the commonly used thread model of programming the success of TinyOS and provide incremental, or even alternative interface to developers. We have used various implementation solutions for many practical issues still being debated in the related techniques to optimize the performance and resource usage of communities.multithreading. RETOS also provides software solutions to separate Writing an operating system for micro sensor platforms poses kernel from user applications, and supports their robust execution on several unprecedented problems. First, the OS implementation MMU-less hardware. The RETOS kernel can be dynamically should consider microcontrollers which typically provide very reconfigured, via loadable kernel framework, so a applicationlimited processing power, memory and battery life-time. The eventoptimized and resource-efficient kernel is constructed. Finally, the driven paradigm for sensor OS is especially favored for the networking architecture in RETOS is designed with a layering resource-constrained environment, and we have seen the concept to provide WSN-specific network abstraction. RETOS proliferation of TinyOS or SOS in this context. Second, the currently supports Atmel ATmegal28, TI MSP430, and Chipcon application programming model should be seriously considered to CC2430 family of microcontrollers. Several real-world WSN provide an easy and convenient programming interface to applications are developed for RETOS and the overall evaluation of application developers, without needing to be aware of underlying the systems is described in the paper.operating system principles. The event-driven operating systems, for example, enforce programmers to structure and program an Categories and Subject Descriptors application as a state machine in terms of tasks and event handlers. D.4.7 [Operating systems]: Organization and DesignUnderstanding this concept is an easy task for experts, but conventional programmers who are accustomed to a process model General Terms of programming may find the concept hard to grasp. Third, a micro Design,eralerimentation, Measurement, Perfonnan...

MicroRNAs (miRNAs), small non-coding RNA molecules, are important biomarkers for research and medical purposes. Here, we describe the development of a fast and simple method using highly fluorescent oligonucleotide-silver nanocluster probes (DNA/AgNCs) to efficiently detect specific miRNAs. Due to the great sequence diversity of miRNAs in humans and other organisms, a uniform strategy for miRNA detection is attractive. The concept presented is an oligonucleotide-based locking-to-unlocking system that can be endowed with miRNA complementarity while maintaining the same secondary structure. The locking-to-unlocking system is based on fold-back anchored DNA templates that consist of a cytosine-rich loop for AgNCs stabilization, an miRNA recognition site and an overlap region for hairpin stabilization. When an miRNA is recognized, fluorescence in the visible region is specifically extinguished in a concentration-dependent manner. Here, the exact composition of the fold-back anchor for the locking-to-unlocking system has been systematically optimized, balancing propensity for loop-structure formation, encapsulation of emissive AgNCs and target sensitivity. It is demonstrated that the applied strategy successfully can detect a number of cancer related miRNAs in RNA extracts from human cancer cell lines.

Wireless sensor networks equipped with various gas sensors have been actively used for air quality monitoring. Previous studies have typically explored system issues that include middleware or networking performance, but most research has barely considered the details of the hardware and software of the sensor node itself. In this paper, we focus on the design and implementation of a sensor board for air pollutant monitoring applications. Several hardware and software issues are discussed to explore the possibilities of a practical WSN-based air pollution monitoring system. Through extensive experiments and evaluation, we have determined the various characteristics of the gas sensors and their practical implications for air pollutant monitoring systems.