76 research outputs found
Characteristics of Nanosilver Ink (UTDAg) Microdroplets and Lines on Polyimide During Inkjet Printing at High Stage Velocity
The performance of printed electronics strongly depends on printing techniques and printing resolution that enhance their electrical and mechanical properties. In this research paper, a Jetlab 4xl was used to control and dispense microdroplets of highly conductive nanosilver ink (UTDAg) on a polyimide substrate. The waveform effect on the droplet generation is characterized by measuring the size and the speed of the drops. The behavior of ejected drops on the substrate is studied by printing lines at different drop spacing and stage velocity. The jetting parameters that drive the piezoelectric actuator were properly determined and two waveforms (bipolar) were created to generate two different droplet characteristics in terms of speed and size. Then, printing on the fly using commands in a script file (called âin scriptâ hereafter) with burst mode (a single burst) was used to print lines with different droplet spacings of 50 ÎŒm, 60 ÎŒm, 70 ÎŒm, 80 ÎŒm, 90 ÎŒm and 100 ÎŒm and stage velocities of 20 mm sâ1, 30 mm sâ1, 40 mm sâ1, and 50 mm sâ1. The spreading behavior of the ejected droplets was investigated as well by printing lines with 250 ÎŒm spacing at the different stage velocities mentioned above. The physical characteristics of the printed lines were studied by optical microscopy and surface profilometry. Finally, the resistance of the printed line at 100 ÎŒm droplet spacing and 50 mm sâ1 stage velocity was measured at curing temperatures of 140 °C and 160 °C
Arabidopsis SWI/SNF chromatin remodeling complex binds both promoters and terminators to regulate gene expression
ATP-dependent chromatin remodeling complexes
are important regulators of gene expression in Eukaryotes.
In plants, SWI/SNF-type complexes have
been shown critical for transcriptional control of
key developmental processes, growth and stress responses.
To gain insight into mechanisms underlying
these roles, we performed whole genome mapping
of the SWI/SNF catalytic subunit BRM in Arabidopsis
thaliana, combined with transcript profiling
experiments. Our data showthatBRM occupies thousands
of sites in Arabidopsis genome, most of which
located within or close to genes. Among identified direct
BRM transcriptional targets almost equal numbers
were up- and downregulated upon BRM depletion,
suggesting that BRM can act as both activator
and repressor of gene expression. Interestingly,
in addition to genes showing canonical pattern of
BRM enrichment near transcription start site, many
other genes showed a transcription termination sitecentred
BRM occupancy profile. We found that BRMbound
3ïżœ gene regions have promoter-like features,
including presence of TATA boxes and high H3K4me3
levels, and possess high antisense transcriptional
activity which is subjected to both activation and
repression by SWI/SNF complex. Our data suggest
that binding to gene terminators and controlling transcription
of non-coding RNAs is another way through
which SWI/SNF complex regulates expression of its
targets
BRAHMA ATPase of the SWI/SNF Chromatin Remodeling Complex Acts as a Positive Regulator of Gibberellin-Mediated Responses in Arabidopsis
SWI/SNF chromatin remodeling complexes perform a pivotal function in the regulation of eukaryotic gene expression. Arabidopsis (Arabidopsis thaliana) mutants in major SWI/SNF subunits display embryo-lethal or dwarf phenotypes, indicating their critical role in molecular pathways controlling development and growth. As gibberellins (GA) are major positive regulators of plant growth, we wanted to establish whether there is a link between SWI/SNF and GA signaling in Arabidopsis. This study revealed that in brm-1 plants, depleted in SWI/SNF BRAHMA (BRM) ATPase, a number of GA-related phenotypic traits are GA-sensitive and that the loss of BRM results in markedly decreased level of endogenous bioactive GA. Transcriptional profiling of brm-1 and the GA biosynthesis mutant ga1-3, as well as the ga1-3/brm-1 double mutant demonstrated that BRM affects the expression of a large set of GA-responsive genes including genes responsible for GA biosynthesis and signaling. Furthermore, we found that BRM acts as an activator and directly associates with promoters of GA3ox1, a GA biosynthetic gene, and SCL3, implicated in positive regulation of the GA pathway. Many GA-responsive gene expression alterations in the brm-1 mutant are likely due to depleted levels of active GAs. However, the analysis of genetic interactions between BRM and the DELLA GA pathway repressors, revealed that BRM also acts on GA-responsive genes independently of its effect on GA level. Given the central position occupied by SWI/SNF complexes within regulatory networks controlling fundamental biological processes, the identification of diverse functional intersections of BRM with GA-dependent processes in this study suggests a role for SWI/SNF in facilitating crosstalk between GA-mediated regulation and other cellular pathways
The Cys-Arg/N-end rule pathway is a general sensor of abiotic stress in flowering plants
Abiotic stresses impact negatively on plant growth, profoundly affecting yield and quality of crops. Although much is known about plant responses, very little is understood at the molecular level about the initial sensing of environmental stress. In plants, hypoxia (low oxygen, which occurs during flooding) is directly sensed by the Cys-Arg/N-end rule pathway of ubiquitin-mediated proteolysis, through oxygen-dependent degradation of group VII Ethylene Response Factor transcription factors (ERFVIIs) via amino-terminal (Nt-) cysteine [1, 2]. Using Arabidopsis (Arabidopsis thaliana) and barley (Hordeum vulgare), we show that the pathway regulates plant responses to multiple abiotic stresses. In Arabidopsis, genetic analyses revealed that response to these stresses is controlled by N-end rule regulation of ERFVII function. Oxygen sensing via the Cys-Arg/N-end rule in higher eukaryotes is linked through a single mechanism to nitric oxide (NO) sensing [3, 4]. In plants, the major mechanism of NO synthesis is via NITRATE REDUCTASE (NR), an enzyme of nitrogen assimilation [5]. Here, we identify a negative relationship between NR activity and NO levels and stabilization of an artificial Nt-Cys substrate and ERFVII function in response to environmental changes. Furthermore, we show that ERFVIIs enhance abiotic stress responses via physical and genetic interactions with the chromatin-remodeling ATPase BRAHMA. We propose that plants sense multiple abiotic stresses through the Cys-Arg/N-end rule pathway either directly (via oxygen sensing) or indirectly (via NO sensing downstream of NR activity). This single mechanism can therefore integrate environment and response to enhance plant survival
ANGUSTIFOLIA3 Binds to SWI/SNF Chromatin Remodeling Complexes to Regulate Transcription during Arabidopsis
Genomic analysis of DELLA protein activity
[EN] Changes in gene expression are the main outcome of hormone signaling cascades that widely control plant physiology. In the case of the hormones gibberellins, the transcriptional control is exerted through the activity of the DELLA proteins, which act as negative regulators in the signaling pathway. This review focuses on recent transcriptomic approaches in the context of gibberellin signaling, which have provided useful information on new processes regulated by these hormones such as the regulation of photosynthesis and gravitropism. Moreover, the enrichment of specific cis-elements among DELLA primary targets has also helped extend the view that DELLA proteins regulate gene expression through the interaction with multiple transcription factors from different families.This study was supported by the Italian Ministry of Education, University, and Research (MIUR) [FIRB Progetto Giovani fellowship to A. L.]; the Spanish Ministry of Science and Innovation [grant Nos. BIO2010-15071 and CSD2007-00057]; the Generalitat Valenciana [grant Nos. ACOMP/2012/251 and PROMETEO/2010/020].Locascio, AAM.; Blazquez Rodriguez, MA.; AlabadĂ Diego, D. (2013). Genomic analysis of DELLA protein activity. Plant and Cell Physiology. 54(8):1229-1237. https://doi.org/10.1093/pcp/pct082S1229123754
Genetic analysis of functional redundancy of BRM ATPase and ATSWI3C subunits of Arabidopsis SWI/SNF chromatin remodelling complexes
Self Validation Through Social Media
Social media has become a predominant part of our society today. It surrounds us 24/7 and with this comes along the effects that we feel from it. The current younger generations have grown up with social media, feeling eyes on them constantly. We have become dependent on the need for likes and comments for self validation. Yet, should we really put these numbers at such a high standard to know our own personal worth. In this paper, we will discuss the sociological effects that social media has had on the human mind, especially those who are in their teenage years.Looking specifically at the aspects of âfear of missing outâ and the rising rates of body dysmorphia present in social media users. Looking at out social media is focused on being the highlight reel of your life and only putting forth the most appealing aspects. Therefore, this shows that we are never truly transparent with our followers or even ourselves
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