scholarly journals ABA Metabolism and Homeostasis in Seed Dormancy and Germination

2021 ◽  
Vol 22 (10) ◽  
pp. 5069
Author(s):  
Naoto Sano ◽  
Annie Marion-Poll
Keyword(s):  
Seed Dormancy ◽  
Current Knowledge ◽  
Fine Tuning ◽  
Environmental Signals ◽  
Hormone Synthesis ◽  
Control Seed ◽  
Functional Relationships ◽  
Aba Metabolism ◽  
Natural Variations ◽  
Germinating Seeds

Abscisic acid (ABA) is a key hormone that promotes dormancy during seed development on the mother plant and after seed dispersal participates in the control of dormancy release and germination in response to environmental signals. The modulation of ABA endogenous levels is largely achieved by fine-tuning, in the different seed tissues, hormone synthesis by cleavage of carotenoid precursors and inactivation by 8′-hydroxylation. In this review, we provide an overview of the current knowledge on ABA metabolism in developing and germinating seeds; notably, how environmental signals such as light, temperature and nitrate control seed dormancy through the adjustment of hormone levels. A number of regulatory factors have been recently identified which functional relationships with major transcription factors, such as ABA INSENSITIVE3 (ABI3), ABI4 and ABI5, have an essential role in the control of seed ABA levels. The increasing importance of epigenetic mechanisms in the regulation of ABA metabolism gene expression is also described. In the last section, we give an overview of natural variations of ABA metabolism genes and their effects on seed germination, which could be useful both in future studies to better understand the regulation of ABA metabolism and to identify candidates as breeding materials for improving germination properties.

scholarly journals From the Outside to the Inside: New Insights on the Main Factors That Guide Seed Dormancy and Germination

Genes ◽  
2020 ◽  
Vol 12 (1) ◽  
pp. 52
Author(s):  
Chiara Longo ◽  
Soyanni Holness ◽  
Veronica De Angelis ◽  
Andrea Lepri ◽  
Sara Occhigrossi ◽  
...  
Keyword(s):  
Seed Dormancy ◽  
Translational Control ◽  
Molecular Mechanisms ◽  
Fine Tuning ◽  
Molecular Control ◽  
Control Seed ◽  
Open Questions ◽  
External Signals ◽  
Developmental Switch ◽  
Seed Dormancy And Germination

The transition from a dormant to a germinating seed represents a crucial developmental switch in the life cycle of a plant. Subsequent transition from a germinating seed to an autotrophic organism also requires a robust and multi-layered control. Seed germination and seedling growth are multistep processes, involving both internal and external signals, which lead to a fine-tuning control network. In recent years, numerous studies have contributed to elucidate the molecular mechanisms underlying these processes: from light signaling and light-hormone crosstalk to the effects of abiotic stresses, from epigenetic regulation to translational control. However, there are still many open questions and molecular elements to be identified. This review will focus on the different aspects of the molecular control of seed dormancy and germination, pointing out new molecular elements and how these integrate in the signaling pathways already known.

scholarly journals Roles of Glutathione in Mediating Abscisic Acid Signaling and Its Regulation of Seed Dormancy and Drought Tolerance

Genes ◽  
2021 ◽  
Vol 12 (10) ◽  
pp. 1620
Author(s):  
Murali Krishna Koramutla ◽  
Manisha Negi ◽  
Belay T. Ayele
Keyword(s):  
Signal Transduction ◽  
Abscisic Acid ◽  
Seed Dormancy ◽  
Growth And Development ◽  
Current Knowledge ◽  
Stomatal Closure ◽  
Redox Homeostasis ◽  
Critical Role ◽  
Stress Conditions ◽  
Signal Perception

Plant growth and development and interactions with the environment are regulated by phytohormones and other signaling molecules. During their evolution, plants have developed strategies for efficient signal perception and for the activation of signal transduction cascades to maintain proper growth and development, in particular under adverse environmental conditions. Abscisic acid (ABA) is one of the phytohormones known to regulate plant developmental events and tolerance to environmental stresses. The role of ABA is mediated by both its accumulated level, which is regulated by its biosynthesis and catabolism, and signaling, all of which are influenced by complex regulatory mechanisms. Under stress conditions, plants employ enzymatic and non-enzymatic antioxidant strategies to scavenge excess reactive oxygen species (ROS) and mitigate the negative effects of oxidative stress. Glutathione (GSH) is one of the main antioxidant molecules playing a critical role in plant survival under stress conditions through the detoxification of excess ROS, maintaining cellular redox homeostasis and regulating protein functions. GSH has recently emerged as an important signaling molecule regulating ABA signal transduction and associated developmental events, and response to stressors. This review highlights the current knowledge on the interplay between ABA and GSH in regulating seed dormancy, germination, stomatal closure and tolerance to drought.

scholarly journals Organization of the Macaque Extrastriate Visual Cortex Re-Examined Using the Principle of Spatial Continuity of Function

2011 ◽  
Vol 105 (1) ◽  
pp. 305-320 ◽  
Author(s):  
T. N. Aflalo ◽  
M.S.A. Graziano
Keyword(s):  
Functional Organization ◽  
Current Knowledge ◽  
Dimensional Space ◽  
Macaque Monkey ◽  
Specific Pattern ◽  
Extrastriate Cortex ◽  
Cortical Function ◽  
Spatial Continuity ◽  
Functional Relationships ◽  
Hierarchical Relationships

How is the macaque monkey extrastriate cortex organized? Is vision divisible into separate tasks, such as object recognition and spatial processing, each emphasized in a different anatomical stream? If so, how many streams exist? What are the hierarchical relationships among areas? The present study approached the organization of the extrastriate cortex in a novel manner. A principled relationship exists between cortical function and cortical topography. Similar functions tend to be located near each other, within the constraints of mapping a highly dimensional space of functions onto the two-dimensional space of the cortex. We used this principle to re-examine the functional organization of the extrastriate cortex given current knowledge about its topographic organization. The goal of the study was to obtain a model of the functional relationships among the visual areas, including the number of functional streams into which they are grouped, the pattern of informational overlap among the streams, and the hierarchical relationships among areas. To test each functional description, we mapped it to a model cortex according to the principle of optimal continuity and assessed whether it accurately reconstructed a version of the extrastriate topography. Of the models tested, the one that best reconstructed the topography included four functional streams rather than two, six levels of hierarchy per stream, and a specific pattern of informational overlap among streams and areas. A specific mixture of functions was predicted for each visual area. This description matched findings in the physiological literature, and provided predictions of functional relationships that have yet to be tested physiologically.

Implications of microRNAs in the pathogenesis of atherosclerosis and prospects for therapy

2021 ◽  
Vol 22 ◽  
Author(s):  
Armita Mahdavi Gorabi ◽  
Mohsen Ghanbari ◽  
Thozhukat Sathyapalan ◽  
Tannaz Jamialahmadi ◽  
Amirhossein Sahebkar
Keyword(s):  
Immune Cell ◽  
Cholesterol Metabolism ◽  
Current Knowledge ◽  
Inflammatory Cells ◽  
Cell Types ◽  
Fine Tuning ◽  
Lipid Uptake ◽  
Atherosclerosis Development ◽  
Signaling Receptors ◽  
Different Cell Types

MicroRNAs (miRNAs) are non-coding RNAs containing around 22 nucleotides, which are expressed in vertebrates and plants. They act as posttranscriptional gene expression regulators, fine-tuning various biological processes in different cell types. There is emerging evidence on their role in different stages of atherosclerosis. In addition to regulating the inflammatory cells involved in atherosclerosis, miRNAs play fundamental roles in the pathophysiology of atherosclerosis such as endothelial cell (EC) dysfunction, the aberrant function of the vascular smooth muscle cell (VSMC) and cholesterol metabolism. Moreover, miRNAs participate in several pathogenic pathways of atherosclerotic plaque development, including their effects on immune cell signaling receptors and lipid uptake. In this study, we review our current knowledge of the regulatory role of miRNAs in various pathogenic pathways underlying atherosclerosis development and also outline potential clinical applications of miRNAs in atherosclerosis.

scholarly journals Gynoecium size and ovule number are interconnected traits that impact seed yield

2020 ◽  
Vol 71 (9) ◽  
pp. 2479-2489 ◽  
Author(s):  
Mara Cucinotta ◽  
Maurizio Di Marzo ◽  
Andrea Guazzotti ◽  
Stefan de Folter ◽  
Martin M Kater ◽  
...  
Keyword(s):  
Seed Yield ◽  
Gene Regulatory Networks ◽  
Regulatory Networks ◽  
Current Knowledge ◽  
Fine Tuning ◽  
World Population ◽  
Meristematic Tissue ◽  
Reproductive Part ◽  
Ovule Number ◽  
Gene Regulatory

Abstract Angiosperms form the largest group of land plants and display an astonishing diversity of floral structures. The development of flowers greatly contributed to the evolutionary success of the angiosperms as they guarantee efficient reproduction with the help of either biotic or abiotic vectors. The female reproductive part of the flower is the gynoecium (also called pistil). Ovules arise from meristematic tissue within the gynoecium. Upon fertilization, these ovules develop into seeds while the gynoecium turns into a fruit. Gene regulatory networks involving transcription factors and hormonal communication regulate ovule primordium initiation, spacing on the placenta, and development. Ovule number and gynoecium size are usually correlated and several genetic factors that impact these traits have been identified. Understanding and fine-tuning the gene regulatory networks influencing ovule number and pistil length open up strategies for crop yield improvement, which is pivotal in light of a rapidly growing world population. In this review, we present an overview of the current knowledge of the genes and hormones involved in determining ovule number and gynoecium size. We propose a model for the gene regulatory network that guides the developmental processes that determine seed yield.

scholarly journals Cracking the context-specific PI3K signaling code

2020 ◽  
Vol 13 (613) ◽  
pp. eaay2940 ◽  
Author(s):  
Ralitsa R. Madsen ◽  
Bart Vanhaesebroeck
Keyword(s):  
Current Knowledge ◽  
Computer Software ◽  
Normal Growth ◽  
Pi3k Pathway ◽  
Primary Immune Deficiency ◽  
Pi3k Signaling ◽  
Environmental Signals ◽  
Technological Advances ◽  
Context Dependent ◽  
Context Specific

Specificity in signal transduction is determined by the ability of cells to “encode” and subsequently “decode” different environmental signals. Akin to computer software, this “signaling code” governs context-dependent execution of cellular programs through modulation of signaling dynamics and can be corrupted by disease-causing mutations. Class IA phosphoinositide 3-kinase (PI3K) signaling is critical for normal growth and development and is dysregulated in human disorders such as benign overgrowth syndromes, cancer, primary immune deficiency, and metabolic syndrome. Despite decades of PI3K research, understanding of context-dependent regulation of the PI3K pathway and of the underlying signaling code remains rudimentary. Here, we review current knowledge on context-specific PI3K signaling and how technological advances now make it possible to move from a qualitative to quantitative understanding of this pathway. Insight into how cellular PI3K signaling is encoded or decoded may open new avenues for rational pharmacological targeting of PI3K-associated diseases. The principles of PI3K context-dependent signal encoding and decoding described here are likely applicable to most, if not all, major cell signaling pathways.

scholarly journals Two Component Regulatory Systems and Antibiotic Resistance in Gram-Negative Pathogens

2019 ◽  
Vol 20 (7) ◽  
pp. 1781 ◽  
Author(s):  
Anjali Y. Bhagirath ◽  
Yanqi Li ◽  
Rakesh Patidar ◽  
Katherine Yerex ◽  
Xiaoxue Ma ◽  
...  
Keyword(s):  
Antibiotic Resistance ◽  
Antimicrobial Resistance ◽  
Pathogenic Bacteria ◽  
Current Knowledge ◽  
Regulation Of Gene Expression ◽  
Gram Negative ◽  
Environmental Signals ◽  
Component Systems ◽  
Two Component ◽  
Two Component Systems

Gram-negative pathogens such as Klebsiella pneumoniae, Acinetobacter baumannii, and Pseudomonas aeruginosa are the leading cause of nosocomial infections throughout the world. One commonality shared among these pathogens is their ubiquitous presence, robust host-colonization and most importantly, resistance to antibiotics. A significant number of two-component systems (TCSs) exist in these pathogens, which are involved in regulation of gene expression in response to environmental signals such as antibiotic exposure. While the development of antimicrobial resistance is a complex phenomenon, it has been shown that TCSs are involved in sensing antibiotics and regulating genes associated with antibiotic resistance. In this review, we aim to interpret current knowledge about the signaling mechanisms of TCSs in these three pathogenic bacteria. We further attempt to answer questions about the role of TCSs in antimicrobial resistance. We will also briefly discuss how specific two-component systems present in K. pneumoniae, A. baumannii, and P. aeruginosa may serve as potential therapeutic targets.

Milk utilization and manipulation of composition in the future

1984 ◽  
Vol 9 ◽  
pp. 17-25 ◽  
Author(s):  
W. Banks ◽  
D. D. Muir
Keyword(s):  
Current Knowledge ◽  
Dairy Product ◽  
Milk Composition ◽  
Raw Material ◽  
Fine Tuning ◽  
Stage Of Lactation ◽  
Heat Treated ◽  
Restrictive Legislation ◽  
Milk Solids ◽  
The Relationship

SUMMARYMilk composition varies greatly throughout the year, due largely to the effects of the diet of the cow and the stage of lactation. Whilst such variations go unremarked with bottled and cartoned milk, they are of major importance to manufacturers who use milk as a raw material. The most obvious example is when the yield of a dairy product is affected, e.g. in Scotland, the volume of milk required to produce 1 kg butter varies between 21.1 and 23.3 1 at different times of the year.In addition, however, some of the more subtle changes in milk composition either affect product quality, e.g. the ease with which butter may be spread, or cause processing difficulties, e.g. instability during heating processes. This paper reviews some of our current knowledge on the relationship between milk composition and the properties of some dairy products — butter, whipping cream, Cheddar cheese, ultra-heat treated milk and full-cream evaporated milk. The aim is to identify those milk components that affect each product or process and then enquire how milk composition may be altered to effect improvements — whether at the farm by dietary manipulation or at the creamery by technological adjustment.It is believed that all the evidence indicates that, despite difficulties due to restrictive legislation, the answer must lie at the creamery. The farmer should concentrate on producing desirable milk solids at the lowest possible cost and leave the technologist to do the fine tuning that leads to improved products.

Managing the tensions between exploration and exploitation in large construction projects

2017 ◽  
Vol 17 (4) ◽  
pp. 492-510 ◽  
Author(s):  
Per Erik Eriksson ◽  
Henrik Szentes
Keyword(s):  
Collaborative Design ◽  
Construction Projects ◽  
Current Knowledge ◽  
Practical Importance ◽  
Fine Tuning ◽  
High Tech ◽  
Exploration And Exploitation ◽  
Structured Interviews ◽  
Firm Level ◽  
Content Type

Purpose Prior studies highlight the importance of building ambidextrous capabilities to achieve both exploitation of current knowledge and technologies to make profits today, and exploration of new knowledge and technologies to adapt to and prepare for tomorrow’s demands. In spite of its theoretical and practical importance, research on organizational ambidexterity in project-based organizations is scarce. Thus, the purpose of the paper is to study how ambidexterity may be managed and how exploration and exploitation may be achieved in construction projects. The research identifies some drivers and barriers to exploration and exploitation and also sheds light on how various management approaches interact and affect exploration and exploitation activities. Design/methodology/approach The empirical material is drawn from 40 semi-structured interviews with managers representing the client, the contractor and the designer involved in each of the seven large construction projects in the sample. Findings In contrast to prior literature in high-tech industries where exploitation focuses on continuous development, exploitation in construction projects often involves adopting conventional methods and solutions based on existing knowledge without any development efforts at all. This may enhance short-term efficiency and lower risk at the project level but increase risk at the firm level. Tight time schedules hinder both radical innovations and incremental developments, and the findings also reveal that to invest in efforts on explorative solutions, it must be possible to exploit the solutions in the same project. Research limitations/implications In this empirical context, the traditional structural and sequential ambidexterity solutions are not sufficient. In construction projects, contextual ambidexterity solutions in which key project actors collaborate in developing systemic innovations and fine-tuning solutions across projects are more effective. Practical implications Sufficient project size and/or long-term contracts over a series of projects enhance both investments in explorative activities and exploitation through continuous developments from project to project. In design–bid–build contracts, the client and consultant often miss opportunities to explore new technical solutions that rely on contractor competencies. Early procurement of contractors (e.g. in collaborative design–build contracts) thereby enables the achievement of both exploration and exploitation. Originality/value This study provides important input to the authors’ understanding of how exploration and exploitation may be managed in project-based industries, which has been scarcely studied in previous ambidexterity literature.

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