Artificially expanded genetic information systems (AEGISs) are unnatural forms of DNA that increase the number of independently replicating nucleotide building blocks. To do this, AEGIS pairs are ...joined by different arrangements of hydrogen bond donor and acceptor groups, all while retaining their Watson–Crick geometries. We report here a unique case where AEGIS DNA has been used to execute a systematic evolution of ligands by exponential enrichment (SELEX) experiment. This AEGIS–SELEX was designed to create AEGIS oligonucleotides that bind to a line of breast cancer cells. AEGIS–SELEX delivered an AEGIS aptamer (ZAP-2012) built from six different kinds of nucleotides (the standard G, A, C, and T, and the AEGIS nonstandard P and Z nucleotides, the last having a nitro functionality not found in standard DNA). ZAP-2012 has a dissociation constant of 30 nM against these cells. The affinity is diminished or lost when Z or P (or both) is replaced by standard nucleotides and compares well with affinities of standard GACT aptamers selected against cell lines using standard SELEX. The success of AEGIS–SELEX relies on various innovations, including (i) the ability to synthesize GACTZP libraries, (ii) polymerases that PCR amplify GACTZP DNA with little loss of the AEGIS nonstandard nucleotides, and (iii) technologies to deep sequence GACTZP DNA survivors. These results take the next step toward expanding the power and utility of SELEX and offer an AEGIS–SELEX that could possibly generate receptors, ligands, and catalysts having sequence diversities nearer to that displayed by proteins.
Evolution of functional six-nucleotide DNA Zhang, Liqin; Yang, Zunyi; Sefah, Kwame ...
Journal of the American Chemical Society,
06/2015, Letnik:
137, Številka:
21
Journal Article
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Axiomatically, the density of information stored in DNA, with just four nucleotides (GACT), is higher than in a binary code, but less than it might be if synthetic biologists succeed in adding ...independently replicating nucleotides to genetic systems. Such addition could also add functional groups not found in natural DNA, but useful for molecular performance. Here, we consider two new nucleotides (Z and P, 6-amino-5-nitro-3-(1'-β-D-2'-deoxyribo-furanosyl)-2(1H)-pyridone and 2-amino-8-(1'-β-D-2'-deoxyribofuranosyl)-imidazo1,2-a-1,3,5-triazin-4(8H)-one). These are designed to pair via complete Watson-Crick geometry. These were added to a library of oligonucleotides used in a laboratory in vitro evolution (LIVE) experiment; the GACTZP library was challenged to deliver molecules that bind selectively to liver cancer cells, but not to untransformed liver cells. Unlike in classical in vitro selection, low levels of mutation allow this system to evolve to create binding molecules not necessarily present in the original library. Over a dozen binding species were recovered. The best had Z and/or P in their sequences. Several had multiple, nearby, and adjacent Zs and Ps. Only the weaker binders contained no Z or P at all. This suggests that this system explored much of the sequence space available to this genetic system and that GACTZP libraries are richer reservoirs of functionality than standard libraries.
(
), also named cascalote, has been known traditionally in México for having cicatrizing and inflammatory properties. Phytochemical reports on
species have identified a high content of phenolic ...compounds and shown antineoplastic effects against cancer cells. The aim of this study was to isolate and identify the active compounds of a water:acetone:ethanol (WAE) extract of
pods and characterize their cytotoxic effect and cell death induction in different cancer cell lines. The compounds isolated and identified by chromatography and spectroscopic analysis were stigmasterol, ethyl gallate and gallic acid. Cytotoxic assays on cancer cells showed different ranges of activities. A differential effect on cell cycle progression was observed by flow cytometry. In particular, ethyl gallate and tannic acid induced G2/M phase cell cycle arrest and showed interesting effect on microtubule stabilization in Hep3B cells observed by immunofluorescence. The induction of apoptosis was characterized by morphological characteristic changes, and was supported by increases in the ratio of Bax/Bcl-2 expression and activation of caspase 3/7. This work constitutes the first phytochemical and cytotoxic study of
and showed the action of its phenolic constituents on cell cycle, cell death and microtubules organization.
The study of Hutchinson–Gilford progeria syndrome (HGPS) has provided important clues to decipher mechanisms underlying aging. Progerin, a mutant lamin A, disrupts nuclear envelope ...structure/function, with further impairment of multiple processes that culminate in senescence. Here, we demonstrate that the nuclear protein export pathway is exacerbated in HGPS, due to progerin‐driven overexpression of CRM1, thereby disturbing nucleocytoplasmic partitioning of CRM1‐target proteins. Enhanced nuclear export is central in HGPS, since pharmacological inhibition of CRM1 alleviates all aging hallmarks analyzed, including senescent cellular morphology, lamin B1 downregulation, loss of heterochromatin, nuclear morphology defects, and expanded nucleoli. Exogenous overexpression of CRM1 on the other hand recapitulates the HGPS cellular phenotype in normal fibroblasts. CRM1 levels/activity increases with age in fibroblasts from healthy donors, indicating that altered nuclear export is a common hallmark of pathological and physiological aging. Collectively, our findings provide novel insights into HGPS pathophysiology, identifying CRM1 as potential therapeutic target in HGPS.
HGPS cells show enhanced nuclear protein export activity due to CRM1 overexpression. Ectopic overexpression of CRM1 recreates HGPS‐associated aging features in normal cells. Pharmacological modulation of CRM1 activity alleviates the HGPS phenotype.
A useful and efficient method to construct diversely substituted 1,2,3,4-tetrahydroquinolines in good to excellent yields has been developed through a catalyst-free Domino Mannich and intramolecular ...Friedel-Crafts alkylation reactions of N-arylamines with paraformaldehyde and electron-rich olefins via the formation of N-aryl-N-alkylmethyleneiminium ions as the key intermediates to afford the target products. Nine of the new compounds were evaluated in the US National Cancer Institute (NCI), where compound 5f (R1 = 6-MeO, R2 = p-ClC6H4 and X = pyrrolidin-2-onyl) presented a remarkable activity against 57 cancer cell lines, with the most important GI50 values ranging from 1.46 to 8.28 μM from in vitro assays. Further studies performed over the active compound 5f on HCT116 colon cancer cells indicated that its effect on cell death is exerted through a cell cycle arrest (S phase) in a dose dependent manner, as well as suppression on the cell proliferation process.
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Este trabajo presenta la evolución de la construcción de institucionalidad orientada a proveer igualdad de oportunidades laborales a hombres y mujeres en Bolivia. Hace especial énfasis en la ...identificación de la normativa nacional (leyes, decretos supremos, convenios internacionales y regulación formal desde el Estado), que incentiva la integración al mercado de trabajo en áreas de STEM (Science, Technology, Engineering, and Mathematics).
Identification and characterization of nodules in soft tissue, including their size, shape, and location, provide a basis for tumor identification. This study proposes an inverse finite‐element (FE) ...based computational framework, for characterizing the size of examined tissue sample and detecting the presence of embedded tumor nodules using instrumented palpation, without a priori anatomical knowledge. The inverse analysis was applied to a model system, the human prostate, and was based on the reaction forces which can be obtained by trans‐rectal mechanical probing and those from an equivalent FE model, which was optimized iteratively, by minimizing an error function between the two cases, toward the target solution. The tumor nodule can be identified through its influence on the stress state of the prostate. The effectiveness of the proposed method was further verified using a realistic prostate model reconstructed from magnetic resonance (MR) images. The results show the proposed framework to be capable of characterizing the key geometrical indices of the prostate and identifying the presence of cancerous nodules. Therefore, it has potential, when combined with instrumented palpation, for primary diagnosis of prostate cancer, and, potentially, solid tumors in other types of soft tissue.
This study proposes an inverse finite‐element based framework, for characterizing the size of examined tissue sample and detecting presence of embedded tumor nodule, without a priori anatomical knowledge. The inverse analysis was applied to human prostate, based on the reaction forces obtained by mechanical probing and those from an equivalent FE model, which was optimized iteratively toward the target. The effectiveness of the method was further verified using a realistic prostate model reconstructed from magnetic resonance (MR) images.
Sodium copper chlorophyllin (SCC) has a genetic damage inhibitory capacity due to its antioxidant action. For this reason, it was considered to investigate its role in the life span of Drosophila ...melanogaster and its relationship with the frequency of somatic mutation induced by gamma rays. Results indicated that SCC alone prolonged the lifespan only in females, but in combination with 20 Gy of gamma rays, the aging delay in both sexes was significant. In addition to confirming that the porphyrin reduces the frequency of mutation, the individuals with the highest mutation load are the individuals who die more quickly, and once they are eliminated, the survivor individuals treated with 20 Gy or with SCC + 20 Gy, died at the same rate. The results together indicate that SCC not only inhibits induced genetic damage, but it also has beneficial effects that probably cause an aging delay of the treated population that need to be investigated.
•Chlorophyllin delays the aging in D. melanogaster females.•Pretreatment with chlorophyllin increases the lifespan of D. melanogaster.•Pretreatment with chlorophyllin decreases damage by free radicals in Drosophila.•Chlorophyllin in combination with 20 Gy decreases Sod and Cat activities.
El objetivo es analizar las actitudes respecto a la importancia de los estudios universitarios para mujeres en México a partir de la Encuesta Mundial de Valores 2018-2022. El procedimiento inicial es ...un ejercicio descriptivo de la postura excluyente contra las mujeres y posteriormente un análisis transversal para comparar cinco periodos con países de América. Con un análisis de dispersión entre la tasa de participación de mujeres en estudios superiores por cada país y el porcentaje más alto de la categoría de la variable dependiente se ofrece una explicación relacional. Por último, mediante dos procedimientos multivariados (análisis de componentes principales y análisis de correspondencias múltiples), se extraen los factores influyentes de un conjunto de variables de control y se analizan las proximidades de las categorías extraídas con las actitudes excluyentes. Los resultados señalan que, a pesar de la tendencia progresiva hacia poca prevalencia de actitudes discriminantes, comparativamente con países americanos se destaca el alto porcentaje de población que señala juicios excluyentes. Se demuestra que entre menor tasa de participación de mujeres en espacios universitarios es mayor la proporción de opiniones discriminantes. Por último, existe proximidad entre la opinión discriminante con categorías de niveles bajos educativos, clases social baja y edades mayores. Al final se discuten los resultados y sus implicaciones.
•Co-crystals of pyrazinamide (PZA) with terephthalic (TPH) and trimesic (TMS) acids.•PZA-TPH co-crystal is formed by acid-py heterosynthons and amide-amide homosynthons.•PZA-TMS co-crystal is formed ...by amide-acid and acid-py heterosynthons.•Crystallography, Hirshfeld maps, pairwise energies, and solubilities were analyzed.•PZA-TPH and PZA-TMS co-crystals present improved thermal stabilities compared to PZA.
Two new co-crystals of pyrazinamide (PZA) with terephthalic (TPH) and trimesic (TMS) acids have been prepared and characterized by single-crystal and powder X-ray diffraction, spectroscopic and thermal analysis, and the corresponding dissolution curves are discussed. PZA-TPH co-crystal is formed by a combination of acid-py heterosynthons and amide-amide homosynthons, while in PZA-TMS co-crystal only amide-acid and acid-py heterosynthons were observed. These interactions are discussed based on hydrogen bonds and pairwise interaction energies calculated using B3LYP/6–31G(d,p) molecular wave functions. Hirshfeld surface analysis shows that the crystal structure is mainly controlled by short OH‧‧‧O, NH‧‧‧O, and OH‧‧‧N hydrogen bonds forming molecular sheets that induce preferred orientations in their powder samples. During single-crystal X-ray diffraction experiments, a sort of anisotropic X-ray induced fluorescent phenomenon was observed. PZA-TPH and PZA-TMS co-crystals present improved thermal stabilities compared to PZA. However, the solubility of co-crystals decrease compared to PZA which remarkably follows the proportionality of the conformer solubility rule. In the co-crystals, the lower solubility is due to the precipitation of the TPH and TMS acids, nevertheless, PZA molecules tend to retain a more stable concentration over time
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