1,451 research outputs found
Application of metabolomics and molecular networking in investigating the chemical profile and antitrypanosomal activity of British bluebells (Hyacinthoides non-scripta)
Bulb, leaf, scape and flower samples of British bluebells (Hyacinthoides non-scripta) were collected regularly for one growth period. Methanolic extracts of freeze-dried and ground samples showed antitrypanosomal activity, giving more than 50% inhibition, for 20 out of 41 samples. High-resolution mass spectrometry was used in the dereplication of the methanolic extracts of the different plant parts. The results revealed differences in the chemical profile with bulb samples being distinctly different from all aerial parts. High molecular weight metabolites were more abundant in the flowers, shoots and leaves compared to smaller molecular weight ones in the bulbs. The anti-trypanosomal activity of the extracts was linked to the accumulation of high molecular weight compounds, which were matched with saponin glycosides, while triterpenoids and steroids occurred in the inactive extracts. Dereplication studies were employed to identify the significant metabolites via chemotaxonomic filtration and considering their previously reported bioactivities. Molecular networking was implemented to look for similarities in fragmentation patterns between the isolated saponin glycoside at m/z 1445.64 [Mā+āformic-H]ā equivalent to C64H104O33 and the putatively found active metabolite at m/z 1283.58 [Mā+āformic-H]ā corresponding to scillanoside L-1. A combination of metabolomics and bioactivity-guided approaches resulted in the isolation of a norlanostane-type saponin glycoside with antitrypanosomal activity of 98.9% inhibition at 20āĀµM
Identification of the major tRNAPhe binding domain in the tetrameric structure of cytoplasmic phenylalanyl-tRNA synthetase from baker's yeast
AbstractNative cytoplasmic phenylalanyl-tRNA synthetase from baker's yeast is a tetramer of the Ī±2Ī²2 type. On mild tryptic cleavage it gives rise to a modified ā”2Ī²ā²2 form that has lost the tRNAPhe binding capacity but is still able to activate phenylalanine. In this paper are presented data concerning peptides released by this limited proteolytic conversion as well as those arising from exhaustive tryptic digestion of the truncated Ī²ā² subunit. Each purified peptide was unambiguously assigned to a unique stretch of the Ī² subunit amino acid sequence that was recently determined via gene cloning and DNA sequencing. Together with earlier results from affinity labelling studies the present data show that the Lys 172āIle 173 bond is the unique target of trypsin under mild conditions and that the N-terminal domain of each Ī² subunit (residues 1ā172) contains the major tRNAPhe binding sites
Community Aliveness: Discovering Interaction Decay Patterns in Online Social Communities
Online Social Communities (OSCs) provide a medium for connecting people,
sharing news, eliciting information, and finding jobs, among others. The
dynamics of the interaction among the members of OSCs is not always growth
dynamics. Instead, a or dynamics often
happens, which makes an OSC obsolete. Understanding the behavior and the
characteristics of the members of an inactive community help to sustain the
growth dynamics of these communities and, possibly, prevents them from being
out of service. In this work, we provide two prediction models for predicting
the interaction decay of community members, namely: a Simple Threshold Model
(STM) and a supervised machine learning classification framework. We conducted
evaluation experiments for our prediction models supported by a of decayed communities extracted from the StackExchange platform. The
results of the experiments revealed that it is possible, with satisfactory
prediction performance in terms of the F1-score and the accuracy, to predict
the decay of the activity of the members of these communities using
network-based attributes and network-exogenous attributes of the members. The
upper bound of the prediction performance of the methods we used is and
for the F1-score and the accuracy, respectively. These results indicate
that network-based attributes are correlated with the activity of the members
and that we can find decay patterns in terms of these attributes. The results
also showed that the structure of the decayed communities can be used to
support the alive communities by discovering inactive members.Comment: pre-print for the 4th European Network Intelligence Conference -
11-12 September 2017 Duisburg, German
Computational Repurposing of Mitoxantrone-Related Structures against Monkeypox Virus : A Molecular Docking and 3D Pharmacophore Study
Acknowledgments: A sincere thanks to P.S. Oberoi (I.C.A.R, N.D.R.I., India) and Rishi Vachaspathy Astakala (Marine Biodiscovery Centre, Department of Chemistry, University of Aberdeen, UK) for their constructive suggestions. Additionally, thank Nidhan Singh Oberoi and Albrn Care, India. Funding: B.F.M. acknowledges national funds from the Portuguese FCTāFundaĆ§Ć£o para a CiĆŖncia e a Tecnologia, I.P., within the projects UIDB/04564/2020 and UIDP/04564/2020.Peer reviewedPublisher PD
Redox Potential: Monitoring and Role in Development of Aroma Compounds, Rheological Properties and Survival of Oxygen Sensitive Strains During the Manufacture of Fermented Dairy Products
International audienc
The primary structure of rabbit liver tRNAPhe and its comparison with known tRNAPhe sequences
Molecular epidemiology of Powassan virus in North America
Powassan virus (POW) is a tick-borne flavivirus distributed in Canada, the northern USA and the Primorsky region of Russia. POW is the only tick-borne flavivirus endemic to the western hemisphere, where it is transmitted mainly between Ixodes cookei and groundhogs (Marmota monax). Deer tick virus (DTV), a genotype of POW that has been frequently isolated from deer ticks (Ixodes scapularis), appears to be maintained in an enzootic cycle between these ticks and white-footed mice (Peromyscus leucopus). DTV has been isolated from ticks in several regions of North America, including the upper Midwest and the eastern seaboard. The incidence of human disease due to POW is apparently increasing. Previous analysis of tick-borne flaviviruses endemic to North America have been limited to relatively short genome fragments. We therefore assessed the evolutionary dynamics of POW using newly generated complete and partial genome sequences. Maximum-likelihood and Bayesian phylogenetic inferences showed two well-supported, reciprocally monophyletic lineages corresponding to POW and DTV. Bayesian skyline plots based on year-of-sampling data indicated no significant population size change for either virus lineage. Statistical model-based selection analyses showed evidence of purifying selection in both lineages. Positive selection was detected in NS-5 sequences for both lineages and envelope sequences for POW. Our findings confirm that POW and DTV sequences are relatively stable over time, which suggests strong evolutionary constraint, and support field observations that suggest that tick-borne flavivirus populations are extremely stable in enzootic foci
A Tribute to Justice Byron R. White
Of 107 Justices in 205 years, only twelve have served longer than thirty years, and every long-serving Justice has made a substantial contribution to the institution - offering a steady and dedicated response to the judicial challenges of an era, asserting leadership at a time of national crisis, or articulating a large constitutional vision. The personal qualities and life experiences that a new Justice brings to the Court contain the seeds of the individual\u27s judicial service. Justice White, a skeptical but unflinching democrat, was no exception
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