Leaf Senescence: Systems and Dynamics Aspects

Woo, Hye Ryun,Kim, Hyo Jung,Lim, Pyung Ok,Nam, Hong Gil Annual Reviews 2019 ANNUAL REVIEW OF PLANT BIOLOGY Vol. No.

<P> Leaf senescence is an important developmental process involving orderly disassembly of macromolecules for relocating nutrients from leaves to other organs and is critical for plants’ fitness. Leaf senescence is the response of an intricate integration of various environmental signals and leaf age information and involves a complex and highly regulated process with the coordinated actions of multiple pathways. Impressive progress has been made in understanding how senescence signals are perceived and processed, how the orderly degeneration process is regulated, how the senescence program interacts with environmental signals, and how senescence regulatory genes contribute to plant productivity and fitness. Employment of systems approaches using omics-based technologies and characterization of key regulators have been fruitful in providing newly emerging regulatory mechanisms. This review mainly discusses recent advances in systems understanding of leaf senescence from a molecular network dynamics perspective. Genetic strategies for improving the productivity and quality of crops are also described. </P>

Responses of the Tropical Atmospheric Circulation to Climate Change and Connection to the Hydrological Cycle

Ma, Jian,Chadwick, Robin,Seo, Kyong-Hwan,Dong, Changming,Huang, Gang,Foltz, Gregory R.,Jiang, Jonathan H. Annual Reviews Inc 2018 Annual review of earth and planetary sciences Vol.46 No.-

<P>This review describes the climate change-induced responses of the tropical atmospheric circulation and their impacts on the hydrological cycle. We depict the theoretically predicted changes and diagnose physical mechanisms for observational and model-projected trends in large-scale and regional climate. The tropical circulation slows down with moisture and stratification changes, connecting to a poleward expansion of the Hadley cells and a shift of the intertropical convergence zone. Redistributions of regional precipitation consist of thermodynamic and dynamical components, including a strong offset between moisture increase and circulation weakening throughout the tropics. This allows other dynamical processes to dominate local circulation changes, such as a surface warming pattern effect over oceans and multiple mechanisms over land. To improve reliability in climate projections, more fundamental understandings of pattern formation, circulation change, and the balance of various processes redistributing land rainfall are suggested to be important.</P>

Membrane materials for addressing energy and environmental challenges.

Drioli, Enrico,Fontananova, Enrica Annual Reviews 2012 Annual review of chemical and biomolecular enginee Vol.3 No.-

<P>Our modern society must solve various severe problems to maintain and increase our quality of life: from water stress to global warming, to fossil fuel depletion, to environmental pollution. The process intensification (PI) strategy is expected to contribute to overcoming many of these issues by facilitating the transition from a resource-intensive to a knowledge-intensive industrial system that will guarantee sustainable growth. Membrane operations, which respond efficiently to the requirements of the PI strategy, have the potential to replace conventional energy-intensive separation techniques, which will boost the efficiency and reduce the environmental impact of separations as well as conversion processes. This work critically reviews the current status and emerging applications of (integrated) membrane operations with a special focus on energy and environmental applications.</P>

Microfluidic Chips for Immunoassays

Han, Kwi Nam,Li, Cheng Ai,Seong, Gi Hun Annual Reviews 2013 Annual review of analytical chemistry Vol.6 No.-

<P>The use of microfluidic chips for immunoassays has been extensively explored in recent years. The combination of immunoassays and microfluidics affords a promising platform for multiple, sensitive, and automatic point-of-care (POC) diagnostics. In this review, we focus on the description of recent achievements in microfluidic chips for immunoassays categorized by their detection method. Following a brief introduction to the basic principles of each detection method, we examine current microfluidic immunosensor detection systems in detail. We also highlight interesting strategies for sensitive immunosensing configurations, multiplexed analysis, and POC diagnostics in microfluidic immunosensors.</P>

Decoding of Light Signals by Plant Phytochromes and Their Interacting Proteins

Bae, Gabyong,Choi, Giltsu Annual Reviews 2008 Annual review of plant biology Vol.59 No.-

<P>Phytochromes are red/far-red light photoreceptors that convert the information contained in external light into biological signals. The decoding process starts with the perception of red light, which occurs through photoisomerization of a chromophore located within the phytochrome, leading to structural changes that include the disruption of intramolecular interactions between the N- and C-terminal domains of the phytochrome. This disruption exposes surfaces required for interactions with other proteins. In contrast, the perception of far-red light reverses the photoisomerization, restores the intramolecular interaction, and closes the interacting surfaces. Light information represented by the concentration of opened interacting surfaces is converted into biological signals through the modulating activity of interacting proteins. This review summarizes plant phytochromes, phytochrome-interacting proteins, and signal transmission from phytochromes to their interacting proteins.</P>

Materials for Flexible, Stretchable Electronics: Graphene and 2D Materials

Kim, Sang Jin,Choi, Kyoungjun,Lee, Bora,Kim, Yuna,Hong, Byung Hee Annual Reviews 2015 Annual review of materials research Vol.45 No.-

<P>Recently, 2D materials have been intensively studied as emerging materials for future electronics, including flexible electronics, photonics, and electrochemical energy storage devices. Among representative 2D materials (such as graphene, boron nitride, and transition metal dichalcogenides) that exhibit extraordinary properties, graphene stands out in the flexible electronics field due to its combination of high electron mobility, high thermal conductivity, high specific surface area, high optical transparency, excellent mechanical flexibility, and environmental stability. This review covers the synthesis, transfer, and characterization methods of graphene and 2D materials and graphene's application to flexible devices as well as comparison with other competing materials.</P>

The N-End Rule Pathway

Tasaki, Takafumi,Sriram, Shashikanth M.,Park, Kyong Soo,Kwon, Yong Tae Annual Reviews 2012 Annual review of biochemistry Vol.81 No.-

<P>The N-end rule pathway is a proteolytic system in which N-terminal residues of short-lived proteins are recognized by recognition components (N-recognins) as essential components of degrons, called N-degrons. Known N-recognins in eukaryotes mediate protein ubiquitylation and selective proteolysis by the 26S proteasome. Substrates of N-recognins can be generated when normally embedded destabilizing residues are exposed at the N terminus by proteolytic cleavage. N-degrons can also be generated through modifications of posttranslationally exposed pro-N-degrons of otherwise stable proteins; such modifications include oxidation, arginylation, leucylation, phenylalanylation, and acetylation. Although there are variations in components, degrons, and hierarchical structures, the proteolytic systems based on generation and recognition of N-degrons have been observed in all eukaryotes and prokaryotes examined thus far. The N-end rule pathway regulates homeostasis of various physiological processes, in part, through interaction with small molecules. Here, we review the biochemical mechanisms, structures, physiological functions, and small-molecule-mediated regulation of the N-end rule pathway.</P>

Structural Biology of the Toll-Like Receptor Family

Kang, Jin Young,Lee, Jie-Oh Annual Reviews 2011 Annual review of biochemistry Vol.80 No.-

<P>Innate immune receptors respond to common structural patterns in microbial molecules and are called pattern recognition receptors. Toll-like receptors (TLRs) play critical roles in the innate immune system by recognizing microbial lipids, carbohydrates, nucleic acids, and proteins. Precise definition of the ligand “pattern” of TLRs has been difficult to determine primarily owing to a lack of high-resolution structures. Recently, the structures of several TLR-ligand complexes and the intracellular signaling domains have been determined by X-ray crystallography. This new structural information, combined with extensive biochemical and immunological data accumulated over decades, sheds new light on ligand-recognition and -activation mechanisms. In this review, we summarize the TLR structures and discuss proposed ligand-recognition and -activation mechanisms.</P>

Bioinspired Hydrogels to Engineer Cancer Microenvironments

Park, Kyung Min,Lewis, Daniel,Gerecht, Sharon Annual Reviews 2017 Annual review of biomedical engineering Vol. No.

<P>Recent research has demonstrated that tumor microenvironments play pivotal roles in tumor development and metastasis through various physical, chemical, and biological factors, including extracellular matrix (ECM) composition, matrix remodeling, oxygen tension, pH, cytokines, and matrix stiffness. An emerging trend in cancer research involves the creation of engineered three-dimensional tumor models using bioinspired hydrogels that accurately recapitulate the native tumor microenvironment. With recent advances in materials engineering, many researchers are developing engineered tumor models, which are promising platforms for the study of cancer biology and for screening of therapeutic agents for better clinical outcomes. In this review, we discuss the development and use of polymeric hydrogel materials to engineer native tumor ECMs for cancer research, focusing on emerging technologies in cancer engineering that aim to accelerate clinical outcomes.</P>

Computer Simulations of Intrinsically Disordered Proteins

Chong, Song-Ho,Chatterjee, Prathit,Ham, Sihyun Annual Reviews 2017 Annual review of physical chemistry Vol.68 No.-

<P>The investigation of intrinsically disordered proteins (IDPs) is a new frontier in structural and molecular biology that requires a new paradigm to connect structural disorder to function. Molecular dynamics simulations and statistical thermodynamics potentially offer ideal tools for atomic-level characterizations and thermodynamic descriptions of this fascinating class of proteins that will complement experimental studies. However, IDPs display sensitivity to inaccuracies in the underlying molecular mechanics force fields. Thus, achieving an accurate structural characterization of IDPs via simulations is a challenge. It is also daunting to perform a configuration-space integration over heterogeneous structural ensembles sampled by IDPs to extract, in particular, protein configurational entropy. In this review, we summarize recent efforts devoted to the development of force fields and the critical evaluations of their performance when applied to IDPs. We also survey recent advances in computational methods for protein configurational entropy that aim to provide a thermodynamic link between structural disorder and protein activity.</P>