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OBJECTIVE: New indices of dyslipidemia, such as the Atherogenic Index of Plasma (AIP) or Castelli Risk Index I and II (CR-I/II), have been tested to predict erectile dysfunction (ED). The aim of this study was to assess the role of these lipidic scores in predicting severe ED and erectile function (EF) worsening in patients who underwent robot-assisted radical prostatectomy (RARP). METHODS: Data from 1249 prostate cancer patients who underwent RARP at our single tertiary academic referral center from September 2021 to April 2023 were reviewed. RARP patients with a complete lipid panel were included in the final analysis. Two independent multivariable logistic regression models (LRMs) were fitted to identify predictors of ED severity and worsening in RARP patients. RESULTS: Among the 357 RARP patients, the median age was 70 (interquartile range [IQR]: 65-74), and the median BMI was 28.4 (IQR: 26-30.4). According to the preoperative IIEF5, 115 (32.2%), 86 (24.5%), 26 (7.3%), and 40 (11.2%) were mild, mild-moderate, moderate, and severe ED patients, respectively. After multivariable LRMs predicting severe ED, only the nerve-sparing (NS) approach (odds ratio [OR]: 0.09) as well as the preoperative IIEF5 score (OR: 0.32) were independent predictors (p < 0.001). After LRMs predicting EF worsening, only preoperative IIEF5 was an independent predictor (OR: 1.42, p < 0.001). CONCLUSION: The power of novel lipidic scores in predicting severe ED and EF worsening in RARP patients was low, and they should not be routinely applied as a screening method in this patient subgroup. Only preoperative IIEF5 and nerve-sparing approaches are relevant in EF prediction after RARP.
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Urinary tract infections (UTIs) are the second most frequent type of infection observed in clinical practice. Gram-negative Enterobacteriaceae are common pathogens in UTIs. Excessive antibiotic use in humans and animals, poor infection control, and increased global travel have accelerated the spread of multidrug-resistant strains (MDR). Carbapenem antibiotics are commonly considered the last line of defense against MDR Gram-negative bacteria; however, their efficacy is now threatened by the increasing prevalence of carbapenem-resistant Enterobacteriaceae (CRE). This comprehensive review aims to explore the biological mechanisms underlying carbapenem resistance and to present a focus on therapeutic alternatives currently available for complicated UTIs (cUTIs). A comprehensive bibliographic search was conducted on the PubMed/MEDLINE, Scopus, and Web of Science databases in December 2023. The best evidence on the topic was selected, described, and discussed. Analyzed with particular interest were the clinical trials pivotal to the introduction of new pharmacological treatments in the management of complicated cUTIs. Additional suitable articles were collected by manually cross-referencing the bibliography of previously selected papers. This overview provides a current and comprehensive examination of the treatment options available for CRE infections, offering a valuable resource for understanding this constantly evolving public health challenge.
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Enterobacteriáceas Resistentes a Carbapenêmicos , Infecções Urinárias , Humanos , Infecções Urinárias/microbiologia , Antibacterianos/farmacologia , Antibacterianos/uso terapêutico , Carbapenêmicos/uso terapêutico , Farmacorresistência Bacteriana MúltiplaRESUMO
Background and Objectives: To describe the predictors of cribriform variant status and perineural invasion (PNI) in robot-assisted radical prostatectomy (RARP) histology. To define the rates of upgrading between biopsy specimens and final histology and their possible predictive factors in prostate cancer (PCa) patients undergoing RARP. Material and Methods: Within our institutional database, 265 PCa patients who underwent prostate biopsies and consecutive RARP at our center were enrolled (2018-2022). In the overall population, two independent multivariable logistic regression models (LRMs) predicting the presence of PNI or cribriform variant status at RARP were performed. In low- and intermediate-risk PCa patients according to D'Amico risk classification, three independent multivariable LRMs were fitted to predict upgrading. Results: Of all, 30.9% were low-risk, 18.9% were intermediate-risk and 50.2% were high-risk PCa patients. In the overall population, the rates of the cribriform variant and PNI at RARP were 55.8% and 71.1%, respectively. After multivariable LRMs predicting PNI, total tumor length in biopsy cores (>24 mm [OR: 2.37, p-value = 0.03], relative to <24 mm) was an independent predictor. After multivariable LRMs predicting cribriform variant status, PIRADS (3 [OR:15.37], 4 [OR: 13.57] or 5 [OR: 16.51] relative to PIRADS 2, all p = 0.01) and total tumor length in biopsy cores (>24 mm [OR: 2.47, p = 0.01], relative to <24 mm) were independent predicting factors. In low- and intermediate-risk PCa patients, the rate of upgrading was 74.4% and 78.0%, respectively. After multivariable LRMs predicting upgrading, PIRADS (PIRADS 3 [OR: 7.01], 4 [OR: 16.98] or 5 [OR: 20.96] relative to PIRADS 2, all p = 0.01) was an independent predicting factor. Conclusions: RARP represents a tailored and risk-adapted treatment strategy for PCa patients. The indication of RP progressively migrates to high-risk PCa after a pre-operative assessment. Specifically, the PIRADS score at mpMRI should guide the decision-making process of urologists for PCa patients.
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Imageamento por Ressonância Magnética Multiparamétrica , Neoplasias da Próstata , Robótica , Masculino , Humanos , Próstata/cirurgia , Próstata/patologia , Incidência , Centros de Atenção Terciária , Prostatectomia/métodos , Neoplasias da Próstata/epidemiologia , Neoplasias da Próstata/cirurgia , Neoplasias da Próstata/patologia , Estudos Retrospectivos , Gradação de TumoresRESUMO
Background and Objectives: Despite advancements in the diagnosis and treatment of testicular germ cell tumours (TGTCs), challenges persist in identifying reliable biomarkers for early detection and precise disease management. This narrative review addresses the role of microRNAs (miRNAs) as potential diagnostic tools and therapeutic targets in the treatment of TGCTs. Materials and Methods: Three databases (PubMed®, Web of Science™, and Scopus®) were queried for studies investigating the utility of miRNA as diagnostic tools, assessing their prognostic significance, and evaluating their potential to guide TGCT treatment. Different combinations of the following keywords were used, according to a free-text protocol: "miRNA", "non-coding RNA", "small RNA", "Testicular Cancer", "seminomatous testicular germ cell", "non-seminomatous testicular germ cell". Results: The potential of miRNAs as possible biomarkers for a non-invasive diagnosis of TGCT is appealing. Their integration into the diagnostic pathway for TGCT patients holds the potential to enhance the discriminative power of conventional serum tumour markers (STMs) and could expedite early diagnosis, given that miRNA overexpression was observed in 50% of GCNIS cases. Among miRNAs, miR-371a-3p stands out with the most promising evidence, suggesting its relevance in the primary diagnosis of TGCT, particularly when conventional STMs offer limited value. Indeed, it demonstrated high specificity (90-99%) and sensitivity (84-89%), with good positive predictive value (97.2%) and negative predictive value (82.7%). Furthermore, a direct relationship between miRNA concentration, disease burden, and treatment response exists, regardless of disease stages. The initial evidence of miRNA decrease in response to surgical treatment and systemic chemotherapy has been further supported by more recent results suggesting the potential utility of this tool not only in evaluating treatment response but also in monitoring residual disease and predicting disease relapse. Conclusions: MiRNAs could represent a reliable tool for accurate diagnosis and disease monitoring in the treatment of TGCT, providing more precise tools for early detection and treatment stratification. Nevertheless, well-designed clinical trials and comprehensive long-term data are needed to ensure their translation into effective clinical tools.
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MicroRNAs , Neoplasias Embrionárias de Células Germinativas , Neoplasias Testiculares , Masculino , Humanos , MicroRNAs/genética , Neoplasias Testiculares/diagnóstico , Neoplasias Testiculares/genética , Neoplasias Testiculares/patologia , Recidiva Local de Neoplasia , Neoplasias Embrionárias de Células Germinativas/diagnóstico , Neoplasias Embrionárias de Células Germinativas/genética , Biomarcadores Tumorais/genéticaRESUMO
BACKGROUND: Severe carotid stenosis (CS) is a major risk factor for stroke. Carotid Endarterectomy (CEA) is the gold standard revascularization technique of CS while carotid artery stenting (CAS) is considered an alternative treatment option, especially in high-risk patients or those with relative contraindications to CEA. The aim of this study was to evaluate the results of CEA and CAS with Roadsaver® stent device. METHODS: We made a retrospective analysis of 119 patients undergoing treatment of CS. All CS were evaluated with imaging exams. The patients were divided into CEA group and CAS group. As primary endpoints of the study overall and cardiovascular cause - related mortality, freedom from stroke, and restenosis were considered. All patients were followed up and revaluated with duplex scan over a minimum of 6 months and a maximum of 36 months (follow-up mean time 22.3 ± 3.4 months). RESULTS: In the whole cohort 86 of 119 patients underwent CEA and 33 of 119 CAS. Risk factors were superposable in both groups. During follow-up, we observed 4 deaths, 2 cardiovascular events and 12 restenosis. CEA was associated with lower death probability than CAS (P = 0.036). Probability of Restenosis and cardiovascular events did not vary between CAS and CEA groups. CONCLUSIONS: Albeit CEA remains the gold standard for the treatment of severe CS, CAS with new double layer micromesh stent can be considered a useful and safe alternative in some clinical conditions.
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Estenose das Carótidas , Endarterectomia das Carótidas , Acidente Vascular Cerebral , Artérias Carótidas , Estenose das Carótidas/diagnóstico por imagem , Estenose das Carótidas/cirurgia , Endarterectomia das Carótidas/efeitos adversos , Humanos , Estimativa de Kaplan-Meier , Recidiva , Estudos Retrospectivos , Fatores de Risco , Stents/efeitos adversos , Acidente Vascular Cerebral/etiologia , Fatores de Tempo , Resultado do TratamentoRESUMO
Background and Objective: Blood loss represents a long-standing concern of radical prostatectomy (RP). This study aimed to assess how red line cell values changed following robot-assisted radical prostatectomy (RARP) for prostate cancer (PCa). Materials and Methods: The blood panels of 453 consecutive PCa patients undergoing RARP at a single tertiary academic referral center, from September 2020 to April 2022, were reviewed. Data from 363 patients with the blood panel available for the following timeframe: within seven days before surgery, six hours after surgery, and the first three postoperative days, were analyzed. Specifically, hemoglobin (Hb, g/dL), red blood cells (RBCs, ×106/µL), and hematocrit (HCT, %) trends were collected. Results: Considering the Hb trend, the median values in the preoperative day, postoperative day (POD) 2, and POD 3 are 14.7 (interquartile range (IQR) = 13.9−15.4), 12.1 (IQR = 11.2−12.9), and 12.2 (IQR = 11.2−13.1), respectively. The ∆ between preoperative day and POD 2 is 2.5 (IQR = 1.8−3.2) (p < 0.001). Considering the RBCs trend, the median values in the preoperative day, POD 2, and POD 3 are 4.9 (IQR = 4.7−5.3), 4.1 (IQR = 3.8−4.4), and 4.1 (IQR = 3.8−4.5), respectively. The ∆ between preoperative day and POD 2 is 0.9 (IQR = 0.6−1.1) (p < 0.001). Considering the HCT trend, the median values in the preoperative day, POD 2, and POD 3 are 44.4 (IQR = 41.7−46.6), 36.4 (IQR = 33.8−38.9), and 36.1 (IQR = 33.5−38.7), respectively. The ∆ between preoperative day and POD 2 is 7.8 (IQR = 5.2−10.5) (p < 0.001). Conclusions: Overall, patients undergoing RARP experience a significant, but clinically limited, decline in red line cell values between the preoperative time and the second day post-surgery. These observations are important to provide physicians with knowledge of the expected postoperative course and, thus, to improve the quality of patient care.
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Neoplasias da Próstata , Procedimentos Cirúrgicos Robóticos , Robótica , Masculino , Humanos , Resultado do Tratamento , Prostatectomia , Neoplasias da Próstata/cirurgia , Eritrócitos , Linhagem CelularRESUMO
The goal of prebiotic chemistry is the depiction of molecular evolution events preceding the emergence of life on Earth or elsewhere in the cosmos. Plausible experimental models require geochemical scenarios and robust chemistry. Today we know that the chemical and physical conditions for life to flourish on Earth were at work much earlier than thought, i.e., earlier than 4.4 billion years ago. In recent years, a geochemical model for the first five hundred million years of the history of our planet has been devised that would work as a cradle for life. Serpentinization processes in the Hadean eon affording self-assembled structures and vesicles provides the link between the catalytic properties of the inorganic environment and the impressive chemical potential of formamide to produce complete panels of organic molecules relevant in pre-genetic and pre-metabolic processes. Based on an interdisciplinary approach, we propose basic transformations connecting geochemistry to the chemistry of formamide, and we hint at the possible extension of this perspective to other worlds.
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Evolução Química , Formamidas/química , Origem da Vida , Catálise , Química Orgânica , Planeta TerraRESUMO
Formation and structural modification of oxygenated polycyclic aromatic hydrocarbons (oxyPAHs) by UV irradiation on minerals have recently been proposed as a possible channel of PAH transformation in astrochemical and prebiotic scenarios of possible relevance for the origin of life. Herein, it is demonstrated that high-energy proton-beam irradiation in the presence of various meteorites, including stony iron, achondrite, and chondrite types, promotes the conversion of two representative oxyPAH compounds, 1-naphthol and 1,8-dihydroxynaphthalene, to complex mixtures of oxygenated and oligomeric derivatives. The main identified products include polyhydroxy derivatives, isomeric dimers encompassing benzofuran and benzopyran scaffolds, and, notably, a range of quinones and perylene derivatives. Addition of urea, a prebiotically relevant chemical precursor, expanded the range of identified species to include, among others, quinone diimines. Proton-beam irradiation of oxyPAH modulated by nitrogen-containing compounds such as urea is proposed as a possible contributory mechanism for the formation and processing of insoluble organic matter in meteorites and in prebiotic processes.
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The condensation of formamide has been shown to be a robust chemical pathway affording molecules necessary for the origin of life. It has been experimentally demonstrated that condensation reactions of formamide are catalyzed by a number of minerals, including silicates, phosphates, sulfides, zirconia, and borates, and by cosmic dusts and meteorites. However, a critical discussion of the catalytic power of the tested minerals, and the geochemical conditions under which the condensation would occur, is still missing. We show here that mineral self-assembled structures forming under alkaline silica-rich solutions are excellent catalysts for the condensation of formamide with respect to other minerals. We also propose that these structures were likely forming as early as 4.4â billion years ago when the whole earth surface was a reactor, a global scale factory, releasing large amounts of organic compounds. Our experimental results suggest that the conditions required for the synthesis of the molecular bricks from which life self-assembles, rather than being local and bizarre, appears to be universal and geologically rather conventional.
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A short history of Campbell's primordial soup: In this essay we try to disclose some of the historical connections between the studies that have contributed to our current understanding of the emergence of catalytic RNA molecules and their components from an inanimate matter.
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Prebióticos , Nucleosídeos/química , Nucleotídeos/química , RNA/metabolismo , RNA Catalítico/metabolismo , Ribossomos/metabolismoRESUMO
It has recently been demonstrated that mineral self-assembled structures catalyzing prebiotic chemical reactions may form in natural waters derived from serpentinization, a geological process widespread in the early stages of Earth-like planets. We have synthesized self-assembled membranes by mixing microdrops of metal solutions with alkaline silicate solutions in the presence of formamide (NH2 CHO), a single-carbon molecule, at 80 °C. We found that these bilayer membranes, made of amorphous silica and metal oxide/hydroxide nanocrystals, catalyze the condensation of formamide, yielding the four nucleobases of RNA, three amino acids and, several carboxylic acids in a single-pot experiment. Besides manganese, iron and magnesium, two abundant elements in the earliest Earth crust that are key in serpentinization reactions, are enough to produce all these biochemical compounds. These results suggest that the transition from inorganic geochemistry to prebiotic organic chemistry is common on a universal scale and, most probably, occurred earlier than ever thought for our planet.
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Ácidos Carboxílicos/química , Formamidas/química , Prebióticos/análise , RNA/química , Silicatos/química , Dióxido de Silício/química , Aminoácidos , Carbono , Catálise , Planeta Terra , ÓxidosRESUMO
Liquid formamide has been irradiated by high-energy proton beams in the presence of powdered meteorites, and the products of the catalyzed resulting syntheses were analyzed by mass spectrometry. Relative to the controls (no radiation, or no formamide, or no catalyst), an extremely rich, variegate, and prebiotically relevant panel of compounds was observed. The meteorites tested were representative of the four major classes: iron, stony iron, chondrites, and achondrites. The products obtained were amino acids, carboxylic acids, nucleobases, sugars, and, most notably, four nucleosides: cytidine, uridine, adenosine, and thymidine. In accordance with theoretical studies, the detection of HCN oligomers suggests the occurrence of mechanisms based on the generation of radical cyanide species (CN·) for the synthesis of nucleobases. Given that many of the compounds obtained are key components of extant organisms, these observations contribute to outline plausible exogenous high-energy-based prebiotic scenarios and their possible boundary conditions, as discussed.
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Evolução Química , Formamidas/química , Formamidas/efeitos da radiação , Meteoroides , Nucleosídeos/síntese química , Nucleosídeos/efeitos da radiação , Aminoácidos/síntese química , Aminoácidos/efeitos da radiação , Ácidos Carboxílicos/síntese química , Ácidos Carboxílicos/efeitos da radiação , Catálise , Modelos Químicos , Estrutura Molecular , Origem da Vida , PrótonsRESUMO
We report that 3',5'-cyclic CMP undergoes nonenzymatic di- and trimerization at 20 °C under dry conditions upon proton or UV irradiation. The reaction involves stacking of the cyclic monomers and subsequent polymerization through serial transphosphorylations between the stacked monomers. Proton- and UV-induced oligomerization of 3',5'-cyclic CMP demonstrates that pyrimidines-similar to purines-might also have taken part in the spontaneous generation of RNA under plausible prebiotic conditions as well as in an extraterrestrial context. The observed polymerization of naturally occurring 3',5'-cyclic nucleotides supports the possibility that the extant genetic nucleic acids might have originated by way of a straight Occamian path, starting from simple reactions between plausibly preactivated monomers.
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CMP Cíclico/química , CMP Cíclico/efeitos da radiação , Oligorribonucleotídeos/síntese química , RNA/síntese química , Dicroísmo Circular , Evolução Química , Modelos Químicos , Polimerização , Prótons , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz , Raios UltravioletaRESUMO
Synthesis of the first RNAs represents one of the cornerstones of the emergence of life. Recent studies demonstrated powerful scenarios of prebiotic synthesis of cyclic nucleotides in aqueous and formamide environments. This raised a question about their thermodynamic stability, a decisive factor determining their accumulation in a prebiotic pool. Here we performed ab initio molecular dynamics simulations at various temperatures in formamide and water to study the relative stabilities of the 2',3' and 3',5' isomers of cyclic nucleotides. The computations show that in an aqueous environment 2',3' cyclic nucleotides are more stable than their 3',5' counterparts at all temperatures up to the boiling point. In contrast, in formamide higher temperatures favor the accumulation of the 3',5' cyclic form, whereas below about 400 K the 2',3' cyclic form becomes more stable. The latter observation is consistent with a formamide-based origin scenario, suggesting that 3',5' cyclic nucleotides accumulated at higher temperatures subsequently allowed oligomerization reactions after fast cooling to lower temperatures. A statistical analysis of the geometrical parameters of the solutes indicates that thermodynamics of cyclic nucleotides in aqueous and formamide environments are dictated by the floppiness of the molecules rather than by the ring strain of the cyclic phosphodiester linkages.
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Formamidas/química , Simulação de Dinâmica Molecular , Nucleotídeos Cíclicos/química , Estabilidade de RNA , Água/química , Isomerismo , Estrutura Molecular , Prebióticos , RNA/química , Soluções/química , Temperatura , TermodinâmicaRESUMO
The pathway from simple abiotically made organic compounds to the molecular bricks of life, as we know it, is unknown. The most efficient geological abiotic route to organic compounds results from the aqueous dissolution of olivine, a reaction known as serpentinization (Sleep, N.H., et al. (2004) Proc. Natl. Acad. Sci. USA 101, 12818-12822). In addition to molecular hydrogen and a reducing environment, serpentinization reactions lead to high-pH alkaline brines that can become easily enriched in silica. Under these chemical conditions, the formation of self-assembled nanocrystalline mineral composites, namely silica/carbonate biomorphs and metal silicate hydrate (MSH) tubular membranes (silica gardens), is unavoidable (Kellermeier, M., et al. In Methods in Enzymology, Research Methods in Biomineralization Science (De Yoreo, J., Ed.) Vol. 532, pp 225-256, Academic Press, Burlington, MA). The osmotically driven membranous structures have remarkable catalytic properties that could be operating in the reducing organic-rich chemical pot in which they form. Among one-carbon compounds, formamide (NH2CHO) has been shown to trigger the formation of complex prebiotic molecules under mineral-driven catalytic conditions (Saladino, R., et al. (2001) Biorganic & Medicinal Chemistry, 9, 1249-1253), proton irradiation (Saladino, R., et al. (2015) Proc. Natl. Acad. Sci. USA, 112, 2746-2755), and laser-induced dielectric breakdown (Ferus, M., et al. (2015) Proc Natl Acad Sci USA, 112, 657-662). Here, we show that MSH membranes are catalysts for the condensation of NH2CHO, yielding prebiotically relevant compounds, including carboxylic acids, amino acids, and nucleobases. Membranes formed by the reaction of alkaline (pH 12) sodium silicate solutions with MgSO4 and Fe2(SO4)3·9H2O show the highest efficiency, while reactions with CuCl2·2H2O, ZnCl2, FeCl2·4H2O, and MnCl2·4H2O showed lower reactivities. The collections of compounds forming inside and outside the tubular membrane are clearly specific, demonstrating that the mineral self-assembled membranes at the same time create space compartmentalization and selective catalysis of the synthesis of relevant compounds. Rather than requiring odd local conditions, the prebiotic organic chemistry scenario for the origin of life appears to be common at a universal scale and, most probably, earlier than ever thought for our planet.
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Ácidos Carboxílicos/química , Origem da Vida , Silicatos/químicaRESUMO
Emergence of the very first RNA or RNA-like oligomers from simple nucleotide precursors is one of the most intriguing questions of the origin of life research. In the current paper, we analyse the mechanism of four non-enzymatic template-free scenarios suggested for the oligomerization of chemically non-modified cyclic and acyclic nucleotides in the literature. We show that amines may have a twofold role in these syntheses: due to their high affinity to bind protons they may activate the phosphorus of the phosphate group via proton transfer reactions, or indirectly they may serve as charge compensating species and influence the self-assembling of nucleotides to supramolecular architectures compatible with the oligomerization reactions. Effect of cations and pH on the reactions is also discussed.
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Evolução Molecular , Nucleotídeos/metabolismo , Oligonucleotídeos/biossíntese , Origem da Vida , RNARESUMO
50â years after the historical Miller-Urey experiment, the formamide-based scenario is perhaps the most powerful concurrent hypothesis for the origin of life on our planet besides the traditional HCN-based concept. The information accumulated during the last 15â years in this topic is astonishingly growing and nowadays the formamide-based model represents one of the most complete and coherent pathways leading from simple prebiotic precursors up to the first catalytically active RNA molecules. In this work, we overview the major events of this long pathway that have emerged from recent experimental and theoretical studies, mainly concentrating on the mechanistic, methodological, and structural aspects of this research.
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Formamidas/química , Oligonucleotídeos/química , RNA/química , Catálise , Oligonucleotídeos/metabolismo , Origem da VidaRESUMO
The origin of life on Earth is one of the most fascinating questions of contemporary science. Extensive research in the past decades furnished diverse experimental proposals for the emergence of first informational polymers that could form the basis of the early terrestrial life. Side by side with the experiments, the fast development of modern computational chemistry methods during the last 20 years facilitated the use of in silico modelling tools to complement the experiments. Modern computations can provide unique atomic-level insights into the structural and electronic aspects as well as the energetics of key prebiotic chemical reactions. Many of these insights are not directly obtainable from the experimental techniques and the computations are thus becoming indispensable for proper interpretation of many experiments and for qualified predictions. This review illustrates the synergy between experiment and theory in the origin of life research focusing on the prebiotic synthesis of various nucleic acid building blocks and on the self-assembly of nucleotides leading to the first functional oligonucleotides.
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Simulação de Dinâmica Molecular , Origem da Vida , Prebióticos , Evolução Química , Ácidos NucleicosRESUMO
Formamide (NH2CHO) has been irradiated in condensed phase at 273 K by 11B-boron beams in the presence of powdered meteorites of the chondrite and stony-iron types. Relative to the controls (no radiation or no catalysis), a variegate panel of compounds was observed, including purine and pyrimidine nucleobases (uracil, cytosine, adenine, and guanine), nucleobase analogues, heterocycles, and carboxylic acids involved in metabolic pathways. The presence of amino imidazole carbonitrile (AICN), 4,6-diamino purine (4,6-DAP) and 2,4-diamino pyrimidine (2,4-DAPy) among the observed products suggests the occurrence of an unified mechanism based on the generation of radical cyanide species (â¢CN). These observations contribute to outline plausible prebiotic scenarios involving 11B-boron as energy source.
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Boro , Formamidas/efeitos da radiação , Íons Pesados , Meteoroides , Origem da Vida , Catálise , Evolução QuímicaRESUMO
The origin of the catalytic activity of ancient oligonucleotides is a largely unexplored field of contemporary science. In the current work we use molecular dynamics simulations to investigate the plausibility of tetraloop-like overhang geometries to initiate transphosphorylation reactions that lead to ligation and terminal cleavage in simple, Watson-Crick (WC) complementary oligoC/oligoG sequences observed experimentally. We show a series of examples of known tetraloop architectures, which can be adopted by the unpaired overhangs of short oligonucleotide sequences for a sufficiently long time to enable chemical reactions that lead to simple ribozyme-like catalytic activity. Thus, our computations demonstrate that the role of non-WC interactions at the emergence of the most ancient catalytic oligonucleotides could be more significant than ever believed.