scholarly journals Identification of Light-Sensitive Phosphorylation Sites on PERIOD That Regulate the Pace of Circadian Rhythms in Drosophila

2015 ◽  
Vol 36 (6) ◽  
pp. 855-870 ◽  
Author(s):  
Evrim Yildirim ◽  
Joanna C. Chiu ◽  
Isaac Edery
Keyword(s):  
Nuclear Accumulation ◽  
Phosphorylation Sites ◽  
Nuclear Entry ◽  
Content Type ◽  
Behavioral Rhythms ◽  
Clock Proteins ◽  
Clock Component ◽  
Localization Signal ◽  
Main Components ◽  
Daily Changes

The main components regulating the pace of circadian (≅24 h) clocks in animals are PERIOD (PER) proteins, transcriptional regulators that undergo daily changes in levels and nuclear accumulation by means of complex multisite phosphorylation programs. In the present study, we investigated the function of two phosphorylation sites, at Ser826 and Ser828, located in a putative nuclear localization signal (NLS) on theDrosophila melanogasterPER protein. These sites are phosphorylated by DOUBLETIME (DBT;Drosophilahomolog of CK1δ/ε), the key circadian kinase regulating the daily changes in PER stability and phosphorylation. Mutant flies in which phosphorylation at Ser826/Ser828 is blocked manifest behavioral rhythms with periods slightly longer than 1 h and with altered temperature compensation properties. Intriguingly, although phosphorylation at these sites does not influence PER stability, timing of nuclear entry, or transcriptional autoinhibition, the phospho-occupancy at Ser826/Ser828 is rapidly stimulated by light and blocked by TIMELESS (TIM), the major photosensitive clock component inDrosophilaand a crucial binding partner of PER. Our findings identify the first phosphorylation sites on core clock proteins that are acutely regulated by photic cues and suggest that some phosphosites on PER proteins can modulate the pace of downstream behavioral rhythms without altering central aspects of the clock mechanism.

No Enhancement of Nuclear Entry by Direct Conjugation of a Nuclear Localization Signal Peptide to Linearized DNA

2003 ◽  
Vol 14 (6) ◽  
pp. 1197-1202 ◽  
Author(s):  
Mitsuhide Tanimoto ◽  
Hiroyuki Kamiya ◽  
Noriaki Minakawa ◽  
Akira Matsuda ◽  
Hideyoshi Harashima
Keyword(s):  
Nuclear Localization ◽  
Signal Peptide ◽  
Nuclear Localization Signal ◽  
Nuclear Entry ◽  
Localization Signal

scholarly journals Ebolavirus VP24 Binding to Karyopherins Is Required for Inhibition of Interferon Signaling

2009 ◽  
Vol 84 (2) ◽  
pp. 1169-1175 ◽  
Author(s):  
Mathieu Mateo ◽  
St. Patrick Reid ◽  
Lawrence W. Leung ◽  
Christopher F. Basler ◽  
Viktor E. Volchkov
Keyword(s):  
Nuclear Localization ◽  
Nuclear Localization Signal ◽  
Nuclear Accumulation ◽  
Interferon Signaling ◽  
Loss Of Function ◽  
Proposed Model ◽  
Localization Signal ◽  
Ifn Γ ◽  
Alpha Beta ◽  
Signal Receptors

ABSTRACT The Ebolavirus VP24 protein counteracts alpha/beta interferon (IFN-α/β) and IFN-γ signaling by blocking the nuclear accumulation of tyrosine-phosphorylated STAT1 (PY-STAT1). According to the proposed model, VP24 binding to members of the NPI-1 subfamily of karyopherin alpha (KPNα) nuclear localization signal receptors prevents their binding to PY-STAT1, thereby preventing PY-STAT1 nuclear accumulation. This study now identifies two domains of VP24 required for inhibition of IFN-β-induced gene expression and PY-STAT1 nuclear accumulation. We demonstrate that loss of function correlates with loss of binding to KPNα proteins. Thus, the VP24 IFN antagonist function requires the ability of VP24 to interact with KPNα.

Comparison of diffused layer prepared using liquid dopant solutions and pastes for solar cell with screen printed electrodes

2016 ◽  
Vol 33 (3) ◽  
pp. 167-171 ◽  
Author(s):  
Kazimierz Drabczyk ◽  
Edyta Wróbel ◽  
Grazyna Kulesza-Matlak ◽  
Wojciech Filipowski ◽  
Krzysztof Waczynski ◽  
...  
Keyword(s):  
Solar Cells ◽  
Ethyl Alcohol ◽  
Diffusion Processes ◽  
Phosphorus Oxychloride ◽  
Low Cost ◽  
Content Type ◽  
Base Solution ◽  
Different Types ◽  
Main Components ◽  
Two Stages

Purpose The purpose of this study is comparison of the diffusion processes performed using the commercial available dopant paste made by Filmtronics and the original prepared liquid dopant solution. To decrease prices of industrially produced silicon-based solar cells, the new low-cost production processes are necessary. The main components of most popular silicon solar cells are with diffused emitter layer, passivation, anti-reflective layers and metal electrodes. This type of cells is prepared usually using phosphorus oxychloride diffusion source and metal pastes for screen printing. The diffusion process in diffusion furnace with quartz tube is slow, complicated and requires expensive equipment. The alternative for this technology is very fast in-line processing using the belt furnaces as an equipment. This approach requires different dopant sources. Design/methodology/approach In this work, the diffusion processes were made for two different types of dopant sources. The first one was the commercial available dopant paste from Filmtronics and the second one was the original prepared liquid dopant solution. The investigation was focused on dopant sources fabrication and diffusion processes. The doping solution was made in two stages. In the first stage, a base solution (without dopants) was made: dropwise deionized (DI) water and ethyl alcohol were added to a solution consisting of tetraethoxysilane (TEOS) and 99.8 per cent ethyl alcohol. Next, to the base solution, orthophosphoric acid dissolved in ethyl alcohol was added. Findings Diffused emitter layers with sheet resistance around 60 Ω/sq were produced on solar grade monocrystalline silicon wafers using two types of dopant sources. Originality/value In this work, the diffusion processes were made for two different types of dopant sources. The first one was the commercial available dopant paste from Filmtronics and the second one was the original prepared liquid dopant solution.

Xenopus nuclear factor 7 (xnf7) possesses an NLS that functions efficiently in both oocytes and embryos

1993 ◽  
Vol 105 (2) ◽  
pp. 389-395
Author(s):  
X. Li ◽  
L.D. Etkin
Keyword(s):  
Transcription Factor ◽  
Zinc Finger ◽  
Nuclear Localization ◽  
Nuclear Localization Signal ◽  
Nuclear Accumulation ◽  
Nuclear Factor ◽  
Zinc Finger Gene ◽  
Early Embryos ◽  
Localization Signal ◽  
Nuclear Phosphoprotein

Xenopus nuclear factor 7 (xnf7) is a nuclear phosphoprotein that is encoded by a member of a novel zinc finger gene family and likely functions as a transcription factor. It possesses a nuclear localization signal (NLS) similar to the bipartite basic NLS of nucleoplasmin, but unlike nucleoplasmin, which re-enters nuclei immediately after fertilization, xnf7 remains cytoplasmic until the mid-blastula transition (MBT). We have measured the accumulation of injected labeled xnf7 protein or protein produced from synthetic xnf7 transcripts in the oocyte nuclei (GV). The data show that the NLS of xnf7 functions efficiently in oocytes. Mutations in either of the bipartite basic domains of the xnf7 NLS inhibit nuclear accumulation, while mutations in the spacer sequences have no effect. The xnf7 NLS linked to pyruvate kinase directs the efficient accumulation of this protein into nuclei of early embryos prior to the MBT. These data suggest that retention of the xnf7 protein during development is the result of a mechanism that interferes with the xnf7 NLS function.

scholarly journals Red- and Blue-Light Sensing in the Plant Pathogen Alternaria alternata Depends on Phytochrome and the White-Collar Protein LreA

mBio ◽  
2019 ◽  
Vol 10 (2) ◽  
Author(s):  
Olumuyiwa Igbalajobi ◽  
Zhenzhong Yu ◽  
Reinhard Fischer
Keyword(s):  
Blue Light ◽  
Alternaria Alternata ◽  
Red Light ◽  
White Collar ◽  
Nuclear Accumulation ◽  
Model Organisms ◽  
Light Induction ◽  
Content Type ◽  
High Osmolarity ◽  
Light Sensing

ABSTRACT The filamentous fungus Alternaria alternata is a common postharvest contaminant of food and feed, and some strains are plant pathogens. Many processes in A. alternata are triggered by light. Interestingly, blue light inhibits sporulation, and red light reverses the effect, suggesting interactions between light-sensing systems. The genome encodes a phytochrome (FphA), a white collar 1 (WC-1) orthologue (LreA), an opsin (NopA), and a cryptochrome (CryA) as putative photoreceptors. Here, we investigated the role of FphA and LreA and the interplay with the high-osmolarity glycerol (HOG) mitogen-activated protein (MAP) kinase pathway. We created loss-of function mutations for fphA, lreA, and hogA using CRISPR-Cas9 technology. Sporulation was reduced in all three mutant strains already in the dark, suggesting functions of the photoreceptors FphA and LreA independent of light perception. Germination of conidia was delayed in red, blue, green, and far-red light. We found that light induction of ccgA (clock-controlled gene in Neurospora crassa and light-induced gene in Aspergillus nidulans) and the catalase gene catA depended on FphA, LreA, and HogA. Light induction of ferA (a putative ferrochelatase gene) and bliC (bli-3, light regulated, unknown function) required LreA and HogA but not FphA. Blue- and green-light stimulation of alternariol formation depended on LreA. A lack of FphA or LreA led to enhanced resistance toward oxidative stress due to the upregulation of catalases and superoxide dismutases. Light activation of FphA resulted in increased phosphorylation and nuclear accumulation of HogA. Our results show that germination, sporulation, and secondary metabolism are light regulated in A. alternata with distinct and overlapping roles of blue- and red-light photosensors. IMPORTANCE Light controls many processes in filamentous fungi. The study of light regulation in a number of model organisms revealed an unexpected complexity. Although the molecular components for light sensing appear to be widely conserved in fungal genomes, the regulatory circuits and the sensitivity of certain species toward specific wavelengths seem different. In N. crassa, most light responses are triggered by blue light, whereas in A. nidulans, red light plays a dominant role. In Alternaria alternata, both blue and red light appear to be important. In A. alternata, photoreceptors control morphogenetic pathways, the homeostasis of reactive oxygen species, and the production of secondary metabolites. On the other hand, high-osmolarity sensing required FphA and LreA, indicating a sophisticated cross talk between light and stress signaling.

scholarly journals Validation of Arnaud’s ethical climate index by public sector auditors in Malaysia

2019 ◽  
Vol 35 (3) ◽  
pp. 345-358
Author(s):  
Chew Har Loke ◽  
Suhaiza Ismail ◽  
A.H. Fatima
Keyword(s):  
Public Sector ◽  
Private Sector ◽  
Ethical Climate ◽  
Climate Index ◽  
Future Research ◽  
Content Type ◽  
Future Studies ◽  
The Public ◽  
Ethical Work Climate ◽  
Main Components

Purpose The purpose of this paper is to empirically test Arnaud’s (2010) ethical climate index (ECI) of measuring ethical work climate (EWC) in the context of Malaysian public sector auditors (PSAs). Design/methodology/approach EWC is conceptualized as four main components with two sub-components. Questionnaires were distributed to the population of PSAs in the Malaysian National Audit Department (NAD). Factor analysis (principal component analysis [PCA]) was used to verify the components of EWC. Findings Results from PCA revealed that EWC, indeed, has four main components. Therefore, the findings of this study provide empirical evidence that validates Arnaud’s (2010) EWC model, although tested on PSAs in Malaysia. Research limitations/implications This paper has a limited purpose, which is to test whether the ECI could be applied to PSAs in Malaysia to derive the original four main components of Arnaud’s EWC. Thus, this study does not evaluate the EWC of PSAs or determine causal relationships between EWC and other variables; these are left to future studies. Practical implications The findings of this study confirm that Arnaud’s (2010) ECI is sufficiently resilient to be applied to the context of PSAs in Malaysia. Hence, future studies could use this index to measure EWC not only in the public sector but also in the private sector. Future research could also further test this index in different contexts. Originality/value Arnaud’s (2010) ECI was originally applied in the context of the private sector in a developed country. Hence, this study adds value by extending the ECI to the public sector in a developing country, Malaysia.

Tourist profiles and attitudes: a comparison between cities in a different phase of the life cycle

2019 ◽  
Vol 6 (4) ◽  
pp. 731-748
Author(s):  
Josep-Francesc Valls Giménez ◽  
Gina Pipoli ◽  
Paulo Rita ◽  
Itziar Labairu-Trenchs
Keyword(s):  
Factor Analysis ◽  
Life Cycle ◽  
Design Methodology ◽  
Universal Model ◽  
Content Type ◽  
City Culture ◽  
The Face ◽  
Advanced Stages ◽  
Main Components ◽  
The City

Purpose The purpose of this paper is to analyse the different typologies of tourists that appear in cities that are in a different position within the destination life cycle. Barcelona and Lisbon, two urban destinations, with a strong growth of tourists in the last two decades, which are in advanced stages of their life cycle, and Lima, which has also expanded in the last ten years, but is in less advanced phases, have been chosen. The approach of the study is to analyse if urban tourists modify their attitude in some way in the face of the advancement of the life cycle of the city and what attitudes are expressed by them. Design/methodology/approach For this purpose, an analysis of main components was performed via factor analysis to reduce the number of dimensions of the 11 descriptive variables and the counterpart of tourist attitudes, following Schwartz’s (2006) research. From the four clusters that emerged – authenticity; innovative and cultural hard; relaxation and not innovative – four attitude variables were selected since they were considered relevant to be analysed according to the life cycle of the city: culture and entertainment; authenticity and online social exhibition; and expensive and cheap price. Findings The results obtained do not allow to straightforwardly conclude that as the life cycle of these three cities advances, the attitude evolves from culture to entertainment, from authenticity towards online social exhibition or from the most expensive to the cheapest. The tourists from Barcelona are mostly associated with entertainment, those from Lisbon are associated with culture and those from Lima are split. However, in the face of authenticity, travellers are prone to it. Regarding the price, those in Barcelona are almost divided equally, whereas those in Lisbon, and especially those in Lima, consider it to be mostly cheap. Originality/value From this study, it can be drawn that the attitude of travellers to these three cities is not conditioned by the life cycle. Globalization and digitalisation put pressure on the traveller by configuring a universal model of behaviour before the urban offer that is associated with other factors, but not with the life cycle of the city.

Environmental education in libraries – theoretical foundations and practical implementation

2020 ◽  
Vol 41 (4/5) ◽  
pp. 279-293 ◽  
Author(s):  
Małgorzata Fedorowicz-Kruszewska
Keyword(s):  
Sustainable Development ◽  
Environmental Education ◽  
Case Studies ◽  
New Paradigm ◽  
Professional Literature ◽  
Content Type ◽  
Multiple Case ◽  
Main Components ◽  
The Impact

PurposeThe purpose of this paper is to explain the concepts related to environmental education in the context of sustainable development, to indicate the links between them as well as to identify and organize elements of library activities that have the potential to implement environmental education.Design/methodology/approachThe method of analysis and criticism of scientific and professional literature and research reports was used. The multiple case study method was also used.FindingsAn analysis of literature and multiple case studies confirms the assumption that sustainable development is now a new paradigm of librarianship. Among the goals of sustainable development are environmental goals, which in libraries can be achieved through environmental education. A broad approach to environmental education has been proposed, which is implemented not only by using library services but also by building green collections, contacts with environmentally involved librarians, using ecological library infrastructure, observing sustainable management methods in libraries, cooperation between the library and the external environment in terms of the natural environment.Research limitations/implicationsAn analysis of 20 case studies was carried out regarding the implementation of pro-environmental measures in libraries. Examination of a larger number of case studies would probably give a more complete picture of this area of activity in libraries. The next stage of research should be the development of standards/guidelines in the field of environmental education in libraries, and then the development of methods and techniques for assessing the quality of library activities in this area and methods for assessing the impact of libraries on society and the environment in the field of environmental education.Practical implicationsThe paper indicates – based on case study analyses – those library elements that have potential in the field of environmental education. They were ordered in categories that were assigned to the three main components of a library: people, artefacts and processes.Social implicationsSustainable development is a new library paradigm. The paper focuses on the environmental area, specifically environmental education. It has been recognized that libraries have considerable potential for environmental education and should be seen as socially responsible organizations that take responsibility for the impact of their decisions and actions on society and the environment.Originality/valueThe paper explains the basic concepts of environmental education and the relationships between them. It defines the area of environmental education in libraries in terms of library activity elements that can be used to organize them according to the three main components of a library, which are people, artefacts and processes. The paper also indicates that sustainable development should be treated as a new paradigm of librarianship, and environmental education as a new research field of library and information science.

scholarly journals Synechocystis KaiC3 Displays Temperature- and KaiB-Dependent ATPase Activity and Is Important for Growth in Darkness

2019 ◽  
Vol 202 (4) ◽  
Author(s):  
Anika Wiegard ◽  
Christin Köbler ◽  
Katsuaki Oyama ◽  
Anja K. Dörrich ◽  
Chihiro Azai ◽  
...  
Keyword(s):  
Atpase Activity ◽  
Circadian Clock ◽  
Atp Hydrolysis ◽  
Synechococcus Elongatus ◽  
Constant Darkness ◽  
Content Type ◽  
Clock Proteins ◽  
Pcc 7942 ◽  
Pcc 6803

ABSTRACT Cyanobacteria form a heterogeneous bacterial group with diverse lifestyles, acclimation strategies, and differences in the presence of circadian clock proteins. In Synechococcus elongatus PCC 7942, a unique posttranslational KaiABC oscillator drives circadian rhythms. ATPase activity of KaiC correlates with the period of the clock and mediates temperature compensation. Synechocystis sp. strain PCC 6803 expresses additional Kai proteins, of which KaiB3 and KaiC3 proteins were suggested to fine-tune the standard KaiAB1C1 oscillator. In the present study, we therefore characterized the enzymatic activity of KaiC3 as a representative of nonstandard KaiC homologs in vitro. KaiC3 displayed ATPase activity lower than that of the Synechococcus elongatus PCC 7942 KaiC protein. ATP hydrolysis was temperature dependent. Hence, KaiC3 is missing a defining feature of the model cyanobacterial circadian oscillator. Yeast two-hybrid analysis showed that KaiC3 interacts with KaiB3, KaiC1, and KaiB1. Further, KaiB3 and KaiB1 reduced in vitro ATP hydrolysis by KaiC3. Spot assays showed that chemoheterotrophic growth in constant darkness is completely abolished after deletion of ΔkaiAB1C1 and reduced in the absence of kaiC3. We therefore suggest a role for adaptation to darkness for KaiC3 as well as a cross talk between the KaiC1- and KaiC3-based systems. IMPORTANCE The circadian clock influences the cyanobacterial metabolism, and deeper understanding of its regulation will be important for metabolic optimizations in the context of industrial applications. Due to the heterogeneity of cyanobacteria, characterization of clock systems in organisms apart from the circadian model Synechococcus elongatus PCC 7942 is required. Synechocystis sp. strain PCC 6803 represents a major cyanobacterial model organism and harbors phylogenetically diverged homologs of the clock proteins, which are present in various other noncyanobacterial prokaryotes. By our in vitro studies we unravel the interplay of the multiple Synechocystis Kai proteins and characterize enzymatic activities of the nonstandard clock homolog KaiC3. We show that the deletion of kaiC3 affects growth in constant darkness, suggesting its involvement in the regulation of nonphotosynthetic metabolic pathways.

Development of a novel micro-ablation system to realise micrometric and well-defined hydrogel structures for tissue engineering applications

2014 ◽  
Vol 20 (6) ◽  
pp. 490-498 ◽  
Author(s):  
C. De Maria ◽  
L. Grassi ◽  
F. Vozzi ◽  
A. Ahluwalia ◽  
G. Vozzi
Keyword(s):  
Tissue Engineering ◽  
Cell Culture ◽  
Laser Ablation ◽  
Laser Beam ◽  
Mechanical Stress ◽  
Content Type ◽  
Cell Functions ◽  
Hydrogel Film ◽  
Hydrogel Matrix ◽  
Main Components

Purpose – This paper aims to develop a novel micro-ablation system to realise micrometric and well-defined hydrogel structures. To engineer a tissue it is necessary to evaluate several aspects, such as cell-cell and cell-substrate interactions, its micro-architecture and mechanical stimuli that act on it. For this reason, it is important to fabricate a substrate which presents a microtopology similar to natural tissue and has chemical and mechanical properties able to promote cell functions. In this paper, well-defined hydrogel structures embedding cells were microfabricated using a purposely developed technique, micro-laser ablation, based on a thulium laser. Its working parameters (laser power emission, stepper motor velocity) were optimised to produce shaded “serpentine” pattern on a hydrogel film. Design/methodology/approach – In this study, initially, swelling/contraction tests on agarose and alginate hydrogel in different solutions of main components of cell culture medium were performed and were compared with the MECpH model. This comparison matched with good approximation experimental measurements. Once known how hydrogel changed its topology, microstructures with a well-defined topology were realised using a purposely developed micro-laser ablation system design. S5Y5 neuroblastoma cell lines were embedded in hydrogel matrix and the whole structure was ablated with a laser microfabrication system. The cells did not show damages due to mechanical stress present in the hydrogel matrix and to thermal increase induced by the laser beam. Findings – The hydrogel structure is able to reproduce extracellular matrix. Initially, the hydrogel swelling/contraction in different solutions, containing the main components of the most common cell culture media, was analysed. This analysis is important to evaluate if cell culture environment could alter microtopology of realised structures. Then, the same topology was realised on hydrogel film embedding neuronal cells and the cells did not show damages due to mechanical stress present in the hydrogel matrix and to thermal increase induced by the laser beam. The interesting obtained results could be useful to realise well-defined microfabricated hydrogel structures embedding cells to guide tissue formation Originality/value – The originality of this paper is the design and realisation of a 3D microfabrication system able to microfabricate hydrogel matrix embedding cells without inducing cell damage. The ease of use of this system and its potential modularity render this system a novel potential device for application in tissue engineering and regenerative medicine area.

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