Publications by authors named "Luis A Vale Silva"

Single-cell transcriptomics and spatially-resolved imaging/sequencing technologies have revolutionized biomedical research. However, they suffer from lack of spatial information and a trade-off of resolution and gene coverage, respectively. We propose DOT, a multi-objective optimization framework for transferring cellular features across these data modalities, thus integrating their complementary information.

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We designed and synthesized , which is ∼21.6% shorter than native , the smallest chromosome in . was designed for attachment to another synthetic chromosome due to concerns surrounding potential instability and karyotype imbalance and is now attached to , yielding the first synthetic yeast fusion chromosome.

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Successful meiotic recombination, and thus fertility, depends on conserved axis proteins that organize chromosomes into arrays of anchored chromatin loops and provide a protected environment for DNA exchange. Here, we show that the stereotypic chromosomal distribution of axis proteins in Saccharomyces cerevisiae is the additive result of two independent pathways: a cohesin-dependent pathway, which was previously identified and mediates focal enrichment of axis proteins at gene ends, and a parallel cohesin-independent pathway that recruits axis proteins to broad genomic islands with high gene density. These islands exhibit elevated markers of crossover recombination as well as increased nucleosome density, which we show is a direct consequence of the underlying DNA sequence.

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The age of precision medicine demands powerful computational techniques to handle high-dimensional patient data. We present MultiSurv, a multimodal deep learning method for long-term pan-cancer survival prediction. MultiSurv uses dedicated submodels to establish feature representations of clinical, imaging, and different high-dimensional omics data modalities.

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Human stem cell-derived hepatocyte-like cells (HLCs) offer an attractive platform to study liver biology. Despite their numerous advantages, HLCs lack critical in vivo characteristics, including cell polarity. Here, we report a stem cell differentiation protocol that uses transwell filters to generate columnar polarized HLCs with clearly defined basolateral and apical membranes separated by tight junctions.

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Article Synopsis
  • During meiotic prophase, topoisomerases I and II (Top1 and Top2) are crucial for managing the topological strain on chromosomal DNA caused by processes like transcription and recombination.
  • Both topoisomerases are found mainly in regions of active genes, especially near meiotic double-strand break hotspots, but they have different impacts on recombination.
  • Disruption of Top1 affects double-strand break induction while temperature-sensitive Top2 mutants show delays in chromosome remodeling, linked to changes in Top2's binding rather than its activity.
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Faithful meiotic chromosome inheritance and fertility rely on the stimulation of meiotic crossover recombination by potentially genotoxic DNA double-strand breaks (DSBs). To avoid excessive damage, feedback mechanisms down-regulate DSBs, likely in response to initiation of crossover repair. In Saccharomyces cerevisiae, this regulation requires the removal of the conserved DSB-promoting protein Hop1/HORMAD during chromosome synapsis.

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Background: Chromatin-immunoprecipitation followed by sequencing (ChIP-seq) is the method of choice for mapping genome-wide binding of chromatin-associated factors. However, broadly applicable methods for between-sample comparisons are lacking.

Results: Here, we introduce SNP-ChIP, a method that leverages small-scale intra-species polymorphisms, mainly SNPs, for quantitative spike-in normalization of ChIP-seq results.

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Stem cells are highly resistant to viral infection compared to their differentiated progeny; however, the mechanism is mysterious. Here, we analyzed gene expression in mammalian stem cells and cells at various stages of differentiation. We find that, conserved across species, stem cells express a subset of genes previously classified as interferon (IFN) stimulated genes (ISGs) but that expression is intrinsic, as stem cells are refractory to interferon.

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Eukaryotic transcription activators stimulate the expression of specific sets of target genes through recruitment of co-activators such as the RNA polymerase II-interacting Mediator complex. Aberrant function of transcription activators has been implicated in several diseases. However, therapeutic targeting efforts have been hampered by a lack of detailed molecular knowledge of the mechanisms of gene activation by disease-associated transcription activators.

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Among existing fungal pathogens, Candida glabrata is outstanding in its capacity to rapidly develop resistance to currently used antifungal agents. Resistance to the class of azoles, which are still widely used agents, varies in proportion (from 5 to 20%) depending on geographical area. Moreover, resistance to the class of echinocandins, which was introduced in the late 1990s, is rising in several institutions.

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Antifungal resistance of Candida species is a clinical problem in the management of diseases caused by these pathogens. In this study we identified from a collection of 423 clinical samples taken from Tunisian hospitals two clinical Candida species (Candida albicans JEY355 and Candida tropicalis JEY162) with decreased susceptibility to azoles and polyenes. For JEY355, the fluconazole (FLC) MIC was 8 μg/ml.

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Three aminodi(hetero)arylamines were prepared via a palladium-catalyzed C-N Buchwald-Hartwig coupling of methyl 3-aminothieno[3,2-b]pyridine-2-carboxylate with different bromonitrobenzenes, followed by reduction of the nitro groups of the coupling products to the corresponding amino compounds. The aminodi(hetero)arylamines thus obtained were evaluated for their growth inhibitory effect on four human tumor cell lines MCF-7 (breast adenocarcinoma), A375-C5 (melanoma), NCI-H460 (non-small cell lung cancer) and HepG(2) (hepatocellular carcinoma). The toxicity to non-tumor cells was also evaluated using a porcine liver primary cell culture (PLP1), established by us.

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A potential antitumoral fluorescent indole derivative, methyl 6-methoxy-3-(4-methoxyphenyl)-1H-indole-2-carboxylate, was evaluated for the in vitro cell growth inhibition on three human tumor cell lines, MCF-7 (breast adenocarcinoma), A375-C5 (melanoma), and NCI-H460 (non-small cell lung cancer), after a continuous exposure of 48 h, exhibiting very low GI50 values for all the cell lines tested (0.25 to 0.33 μM).

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The methyl 3-amino-6-bromothieno[3,2-b]pyridine-2-carboxylate, recently reported by some of us, was reacted in Sonogashira couplings with several (hetero)arylacetylenes. The growth inhibitory activity of the novel methyl 3-amino-6-[(hetero)arylethynyl]thieno[3,2-b]pyridine-2-carboxylates obtained was evaluated on three human tumor cell lines (MCF-7, NCI-H460, A375-C5). The para-methoxyphenyl and the ortho- and para-aminophenyl derivatives were the most promising compounds, and their effects were further studied regarding alterations in the normal cell cycle distribution and induction of apoptosis in the NCI-H460 cell line.

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Several novel 6-[(hetero)arylamino]thieno[3,2-b]pyridines were prepared by palladium-catalyzed C-N Buchwald-Hartwig coupling of the methyl 3-amino-6-bromothieno[3,2-b]pyridine-2-carboxylate with aryl and heteroarylamines, using different reaction conditions. The antitumoral activity of the di(hetero)arylamines obtained was evaluated against three representative human tumor cell lines, namely breast adenocarcinoma (MCF-7), melanoma (A375-C5), and non-small cell lung cancer (NCI-H460) and some structure-activity relationships were established within each series. The most promising compounds were shown to be a benzothiazole derivative with GI50 3.

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A wide variety of new bi(hetero)aryl derivatives of the thieno[3,2-b]pyridine skeleton was obtained in high to excellent yields (65-91%) by Suzuki-Miyaura cross-coupling of the methyl 3-amino-6-bromothieno[3,2-b]pyridine-2-carboxylate, recently reported by us, with aryl or heteroaryl pinacolboranes or potassium trifluoroborates. The coupling products obtained were evaluated for their growth inhibitory effect on three human tumor cell lines, representing different tumor models, MCF-7 (breast adenocarcinoma), A375-C5 (melanoma) and NCI-H460 (non-small cell lung cancer). Some of the compounds showed an interesting activity against the tested cell lines, with GI50 values in the μM range, and it was possible to establish some structure-activity relationships (SARs).

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Lycopersicon esculentum (tomato) fruit is a widely studied matrix. However, only few works focus their attention on its seeds, which constitute a major byproduct of the tomato processing industry. In this study the antimicrobial potential of ten different tomato seed extracts from "Bull's heart" and "Cherry" varieties were analyzed against Gram-positive (Staphylococcus aureus, Staphylococcus epidermidis, Micrococcus luteus, Enterococcus faecalis and Bacillus cereus) and Gram-negative (Proteus mirabilis, Escherichia coli, Pseudomonas aeruginosa and Salmonella typhimurium) bacteria and fungi (Candida albicans, Aspergillus fumigatus and Trichophyton rubrum).

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The essential oil (EO) of Thymus x viciosoi (Pau) R. Morales was isolated and analysed by GC and GC-MS. The antifungal activity of the EO and its major components against clinically relevant yeasts and molds was then measured.

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Several novel 3-(aryl)benzothieno[2,3-c]pyran-1-ones (tricyclic lactones) were prepared either by a tandem one-pot Sonogashira coupling and intramolecular cyclization, reacting the 3-bromobenzo[b]thiophene-2-carboxylic acid with arylacetylenes, or by Sonogashira coupling of the methyl 3-bromobenzo[b]thiophene-2-carboxylate or the methyl 3-bromo-6-methoxybenzo[b]thiophene-2-carboxylate with arylacetylenes followed by an electrophilic intramolecular cyclization using iodine or TFA in two separate steps. The Sonogashira products and the tricyclic lactones obtained were evaluated for their capacity to inhibit the in vitro growth of three human tumor cell lines, MCF-7 (breast adenocarcinoma), NCI-H460 (non-small cell lung cancer) and SF-268 (CNS cancer). Most of the compounds showed a high growth inhibitory effect on all the tested cell lines, with GI(50) values in the muM range.

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The antifungal activity of several di(hetero)arylamine derivatives of the benzo[b]thiophene system was evaluated against clinically relevant Candida, Aspergillus, and dermatophyte species by a broth macrodilution test based on CLSI (formerly NCCLS) guidelines. The most active compound showed a broad spectrum of activity (against all tested fungal strains, including fluconazole-resistant fungi), with particularly low MICs for dermatophytes. Results from the inhibition of the dimorphic transition in Candida albicans and flow cytometry studies further confirmed their biological activity.

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The current increase in the number and significance of fungal infections, the expanding armamentarium of antifungal agents, and the emergence of the problem of antifungal drug resistance have been intensifying the importance of antifungal susceptibility testing (AST). The Clinical and Laboratory Standards Institute (CLSI, formerly NCCLS) in the United States and the Antifungal Susceptibility Testing Subcommittee of the European Committee on Antimicrobial Susceptibility Testing (AFST-EUCAST) published standard methodologies in order to achieve higher reproducibility and allow direct inter-laboratory comparison of the susceptibility results. Nevertheless, several problems remain unresolved and the methods depend on long incubation periods of a minimum of 24 h (EUCAST) or even 48 h (CLSI).

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The mechanism of action of the antifungal agent 3-(4-bromophenyl)-5-acyloxymethyl-2,5-dihydrofuran-2-one against Candida albicans was investigated by flow cytometry, using propidium iodide, DiBAC4(3), and FUN-1 as the fluorescent dyes. A related but less active agent, together with amphotericin B and fluconazole, was tested in parallel for comparison of the results. The incrustoporine derivative was found to have a potent fungicidal activity on C.

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