ANTI-SILENCING FUNCTION1 (ASF1) is a key historie H3/H4 chaperone that participates in a variety of DNA-and chromatin-related processes, including DNA repair, where chromatin assembly and disassembly ...are of primary relevance. Information concerning the role of ASF1 proteins in the post-ultraviolet (UV) response in higher plants is currently limited. In Arabidopsis (Arabidopsis thaliana), an initial analysis of in vivo localization of ASF1A and ASF1B indicates that both proteins are mainly expressed in proliferative tissues. In silico promoter analysis identified ASF1A and ASF1B as potential targets of Elongation Factor2 (E2F) transcription factors. These observations were experimentally validated, both in vitro, by electrophoretic mobility shift assays, and in vivo, by chromatin immunoprecipitation assays and expression analysis using transgenic plants with altered levels of different E2F transcription factors. These data suggest that ASF1A and ASF1B are regulated during cell cycle progression through E2F transcription factors. In addition, we found that ASF1A and ASF1B are associated with the UV-B-induced DNA damage response in Arabidopsis. Transcript levels of ASF1A and ASF1B were increased following UV-B treatment. Consistent with a potential role in UV-B response, RNA interference-silenced plants of both genes showed increased sensitivity to UV-B compared with wild-type plants. Finally, by coimmunoprecipitation analysis, we found that ASF1 physically interacts with amino-terrninal acetylated histones H3 and H4 and with acetyltransferases of the Histone Acety1 Transferase subfamily, which are known to be involved in cell cycle control and DNA repair, among other functions. Together, we provide evidence that ASF1A and ASF1B are regulated by cell cycle progression and are involved in DNA repair after UV-B irradiation.
•New ferrocenylated Hypervalent bismuth compounds.•N / O donor pendant arm in ligands.•Synthesis and Characterization of new 1,1’-2-trisubstituted ferrocenyl-dibismuthines.•X-ray structure of ...1,1′-2-trisubstituted ferrocenyl dibismuthines.
New unsymmetrical chiral 1,1′-2-ferrocenyl dibismuthines (C5H4)(BiPh2)Fe(2-{Me2NCH(R)}C5H3)(BiPh2) containing 2-(Me2NCH(R) where R = Me (1) or H (3) pendant arm on ferrocenyl ring were synthesized. An unsymmetrical 1,1′-ferrocenyl-bismuthine (5) in a low yield and 1,1′-2-ferrocenyl chlorodibismuthine (11) as an impurity were also isolated from the reaction mixture. Furthermore, Monoammonium salt CpFe{2-(Me3N+CH2)C5H3}(BiPh2)2I− (6) and 1,1´,2-vinylferrocenyl dibismuthine derivative (7) were obtained by the reaction of CH3I with (3) and (1) respectively. The nucleophilic substitution reaction of (6) by o-hydroxyacetaphenone, salicylaldehyde, and N-methyl piperazine in acetonitrile gave the new functionalized 1,1′-2-substituted ferrocenyl dibismuthines (C5H4)(BiPh2)Fe{2-(RCH2)C5H3}BiPh2 where R = OC6H4-2-C(O)Me (8), OC6H4-2-C(O)H (9) and N(CH2CH2)2NMe (10) respectively with different N or O containing pendant arm. 1,2-disubstituted ferrocenyl compounds presented in this work present planar chirality. These new compounds were characterized by IR, 1H-NMR, 13C-NMR spectroscopy, and High-Resolution Mass Spectrometry (HRMS). The X-ray structures of 1,1´,2-trisubstituted ferrocenyl dibismuthines (10) and (11) were determined. The molecular structure of (11) shows hypervalent Bi···N bonding in the solid-state. The compound (11) has planar chirality, central chirality, and Bi center-chirality with pseudo-trigonal bipyramidal geometry (see-saw structure) around the chiral Bi center while the other bismuth atom has distorted trigonal pyramidal geometry. The variable temperature 1H-NMR spectra of compound (3) in −40°C to 40°C range in CDCl3 indicates a lack of Bi···N coordination.
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ABSTRACT The many unusual properties of the enigmatic AT2018cow suggested that at least some subset of the empirical class of fast blue optical transients (FBOTs) represents a genuinely new ...astrophysical phenomenon. Unfortunately, the intrinsic rarity and fleeting nature of these events have made it difficult to identify additional examples early enough to acquire the observations necessary to constrain theoretical models. We present here the Zwicky Transient Facility discovery of AT2020xnd (ZTF20acigmel, the ‘Camel’) at z = 0.243, the first unambiguous AT2018cow analogue to be found and confirmed in real time. AT2018cow and AT2020xnd share all key observational properties: a fast optical rise, sustained high photospheric temperature, absence of a second peak attributable to ejection of a radioactively heated stellar envelope, extremely luminous radio, millimetre, and X-ray emission, and a dwarf-galaxy host. This supports the argument that AT2018cow-like events represent a distinct phenomenon from slower-evolving radio-quiet supernovae, likely requiring a different progenitor or a different central engine. The sample properties of the four known members of this class to date disfavour tidal disruption models but are consistent with the alternative model of an accretion powered jet following the direct collapse of a massive star to a black hole. Contextual filtering of alert streams combined with rapid photometric verification using multiband imaging provides an efficient way to identify future members of this class, even at high redshift.
Software Reference Architectures (SRAs) play a fundamental role for organizations whose business greatly depends on the efficient development and maintenance of complex software applications. ...However, little is known about the real value and risks associated with SRAs in industrial practice.
To investigate the current industrial practice of SRAs in a single company from the perspective of different stakeholders.
An exploratory case study that investigates the benefits and drawbacks perceived by relevant stakeholders in nine SRAs designed by a multinational software consulting company.
The study shows the perceptions of different stakeholders regarding the benefits and drawbacks of SRAs (e.g., both SRA designers and users agree that they benefit from reduced development costs; on the contrary, only application builders strongly highlighted the extra learning curve as a drawback associated with mastering SRAs). Furthermore, some of the SRA benefits and drawbacks commonly highlighted in the literature were remarkably not mentioned as a benefit of SRAs (e.g., the use of best practices). Likewise, other aspects arose that are not usually discussed in the literature, such as higher time-to-market for applications when their dependencies on the SRA are managed inappropriately.
This study aims to help practitioners and researchers to better understand real SRAs projects and the contexts where these benefits and drawbacks appeared, as well as some SRA improvement strategies. This would contribute to strengthening the evidence regarding SRAs and support practitioners in making better informed decisions about the expected SRA benefits and drawbacks. Furthermore, we make available the instruments used in this study and the anonymized data gathered to motivate others to provide similar evidence to help mature SRA research and practice.
The title compound, Fe(C
5
H
5
)(C
8
H
7
N
2
S), was synthesized by the direct reaction of acetylferrocene, thiourea and resublimed iodine. The structure shows one molecule in the asymmetric unit. ...The aminothiazole ring makes an angle of 14.53 (13)° with the ferrocenyl ring to which it is attached. In the crystal, pairs of complex molecules interact
via
intermolecular N—H...N hydrogen bonds, forming a cyclic dimer which then interacts with other dimers through C—H...π interactions.
Deleterious effects of UV-B radiation on DNA include the formation of cyclobutane pyrimidine dimers (CPDs) and pyrimidine (6–4) pyrimidone photoproducts (6–4PPs). These lesions must be repaired to ...maintain the integrity of DNA and provide genetic stability. Of the several repair systems involved in the recognition and removal of UV-B-induced lesions in DNA, the focus in the present study was on the mismatch repair system (MMR). The contribution of MutSα (MSH2–MSH6) to UV-induced DNA lesion repair and cell cycle regulation was investigated. MSH2 and MSH6 genes in Arabidopsis and maize are up-regulated by UV-B, indicating that MMR may have a role in UV-B-induced DNA damage responses. Analysis of promoter sequences identified MSH6 as a target of the E2F transcription factors. Using electrophoretic mobility shift assays, MSH6 was experimentally validated as an E2F target gene, suggesting an interaction between MMR genes and the cell cycle control. Mutations in MSH2 or MSH6 caused an increased accumulation of CPDs relative to wild-type plants. In addition, msh2 mutant plants showed a different expression pattern of cell cycle marker genes after the UV-B treatment when compared with wild-type plants. Taken together, these data provide evidence that plant MutSα is involved in a UV-B-induced DNA damage response pathway.
1,1′-Diformylruthenocene, Ru(C
6
H
5
O)
2
, crystallizes in the orthorhombic system in the
P
2
1
2
1
2
1
space group at room temperature. There are two crystallographically independent molecules in ...the asymmetric unit. The cyclopentadienyl rings have eclipsed configuration. The molecules self-assemble in a two-dimensional structure by C—H...O and C—H...π interactions with
cisoid
relative orientations of the two formyl groups. The crystal studied was refined as an inversion twin.
Open Source Software (OSS) has become a strategic asset for a number of reasons, such as short time-to-market software delivery, reduced development and maintenance costs, and its customization ...capabilities. Therefore, organizations are increasingly becoming OSS adopters, either as a result of a strategic decision or because it is almost unavoidable nowadays, given the fact that most commercial software also relies at some extent in OSS infrastructure. The way in which organizations adopt OSS affects and shapes their businesses. Therefore, knowing the impact of different OSS adoption strategies in the context of an organization may help improving the processes undertaken inside this organization and ultimately pave the road to strategic moves. In this paper, we propose to model OSS adoption strategies using a goal-oriented notation, in which different actors state their objectives and dependencies on each other. These models describe the consequences of adopting one such strategy or another: which are the strategic and operational goals that are supported, which are the resources that emerge, etc. The models rely on an OSS ontology, built upon a systematic literature review, which comprises the activities and resources that characterize these strategies. Different OSS adoption strategy models arrange these ontology elements in diverse ways. In order to assess which is the OSS adoption strategy that better fits the organization needs, the notion of model coverage is introduced, which allows to measure the degree of concordance among every strategy with the model of the organization by comparing the respective models. The approach is illustrated with an example of application in a big telecommunications company.
The crystal and molecular structure of 2-amino-4-ferrocenylthiazole has been determined. The crystal packing features intermolecular N—H⋯N and C—H⋯π interactions.
The title compound, Fe(C
5
H
5
...)(C
8
H
7
N
2
S), was synthesized by the direct reaction of acetylferrocene, thiourea and resublimed iodine. The structure shows one molecule in the asymmetric unit. The aminothiazole ring makes an angle of 14.53 (13)° with the ferrocenyl ring to which it is attached. In the crystal, pairs of complex molecules interact
via
intermolecular N—H⋯N hydrogen bonds, forming a cyclic dimer which then interacts with other dimers through C—H⋯π interactions.
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