Total synthesis of polysaccharides by automated glycan assembly

Polysaccharides are the most abundant biopolymers on earth that serve various structural and modulatory functions. Pure, completely defined linear and branched polysaccharides are essential to understand carbohydrate structure and function. Polysaccharide isolation provides heterogeneous mixtures, while heroic efforts were required to complete chemical and/or enzymatic syntheses of polysaccharides as long 92-mers. Here, we show that automated glycan assembly (AGA) enables access to a 100-mer polysaccharide via a 201-step synthesis within 188 h. Convergent block coupling of 30- and 31-mer oligosaccharide fragments, prepared by AGA, yielded a multiple-branched 151-mer polymannoside. Quick access to polysaccharides provides the basis for future material science applications of carbohydrates

Predicting Sentence-Level Factuality of News and Bias of Media Outlets

Predicting the factuality of news reporting and bias of media outlets is surely relevant for automated news credibility and fact-checking. While prior work has focused on the veracity of news, we propose a fine-grained reliability analysis of the entire media. Specifically, we study the prediction of sentence-level factuality of news reporting and bias of media outlets, which may explain more accurately the overall reliability of the entire source. We first manually produced a large sentence-level dataset, titled "FactNews", composed of 6,191 sentences expertly annotated according to factuality and media bias definitions from AllSides. As a result, baseline models for sentence-level factuality prediction were presented by fine-tuning BERT. Finally, due to the severity of fake news and political polarization in Brazil, both dataset and baseline were proposed for Portuguese. However, our approach may be applied to any other language

Geoinformation density: a criterion on anh block negotiation

Based on the general information included within the ANH Exploration and Production Information Service, the information distribution densities of the Colombian territory were determined. Thesedensities are referred in seismic length per square kilometer and amounts in magnetic-gravimetric and geochemical information data or drill-hole length per sq. km. A probabilistic distribution wasassessed along the density distribution and cost distribution for each variable. The variables, as information layers, were cross-referenced in order to define relative weights that assess information with respect to the presence or absence of information in the treated area.This procedure could be regarded as a methodological support proposal for area negotiation of the oil industry. A better approach to the quandary should include: new input of data into the system, a division of the territory in smaller areas adjusting to complex geometries, and considering the particular market conditions for each basin. Nevertheless, it is apparent that the obtained results favorthe consolidation of a conceptual framework that at medium term will allow a conscious approach towards block negotiation between the petroleum industry and the ANH

Perfil genético de la población de gatos (Felis catus) en Riohacha, la Guajira, mediante genes de pelaje

En el gato doméstico (Felis catus), la presencia de genes que codifican la coloración, el diseño y la longitud del pelaje, que se caracterizan por su herencia mendeliana y su fácil identificación fenotípica. Además su comportamiento reproductor no está controlado por el hombre, al igual que su vertiginoso incremento demográfico y su distribución casi mundial, ha convertido al gato doméstico, en una especie útil para la genética de poblaciones. El objetivo fue evaluar el perfil genético de las poblaciones de gatos domésticos (Felis catus) mediante genes del pelaje en Riohacha, La Guajira. Se efectuaron muestreos aleatorios de julio a septiembre del año 2015, en 267 animales adultos de seis barrios de Riohacha, utilizando marcadores de pelaje, cada animal se caracterizó fenotípicamente atendiendo a los marcadores de codificación morfológica: el locus ligado al sexo Orange (O) y los loci autosómicos Non-agouti (a), Tabby blotched (Tb), Dilution (d), Pelo largo (l) Manchado de blanco (S) y Dominante blanco (W). El marcador Non-agouti mostró la mayor frecuencia mientras los genes: Dominante blanco y pelo largo exhibió el valor más bajo. Se obtuvieron bajos valores de variabilidad genética a nivel global y poblacional. Así mismo, se obtuvo una escasa diferenciación genética entre poblaciones, acompañado de un elevado flujo génico; se observó exceso de heterocigotos a nivel poblacional y a nivel total y ausencia de equilibrio Hardy-Weinberg respecto a los marcadores Orange y Manchado de blanco. Se logró establecer que las poblaciones se encuentran muy relacionadas genéticamente

Analysis of Synthetic Monodisperse Polysaccharides by Wide Mass Range Ultrahigh-Resolution MALDI Mass Spectrometry

Carbohydrates, such as oligo- and polysaccharides, are highly abundant biopolymers that are involved in numerous processes. The study of their structure and functions is commonly based on a material that is isolated from complex natural sources. However, a more precise analysis requires pure compounds with well-defined structures that can be obtained from chemical or enzymatic syntheses. Novel synthetic strategies have increased the accessibility of larger monodisperse polysaccharides, posing a challenge to the analytical methods used for their molecular characterization. Here, we present wide mass range ultrahigh-resolution matrix-assisted laser desorption/ionization (MALDI) Fourier transform ion cyclotron resonance (FT-ICR) mass spectrometry (MS) as a powerful platform for the analysis of synthetic oligo- and polysaccharides. Synthetic carbohydrates 16-, 64-, 100-, and 151-mers were mass analyzed and characterized by MALDI in-source decay FT-ICR MS. Detection of fragment ions generated from glycosidic bond cleavage (or cross-ring cleavage) provided information of the monosaccharide content and the linkage type, allowing for the corroboration of the carbohydrate compositions and structures

Importance of the urinary system evaluation in adult patients with spina bifida

Los pacientes con espina bífida pueden presentar defectos multisistémicos siendo el sistema urinario uno de los principales en afectarse. En las últimas décadas ha aumentado la población de pacientes adultos con espina bífida debido a la mejora en la sobrevida desde la edad pediátrica, por lo que surge la necesidad de conocer el manejo de estos pacientes tanto por el equipo de salud tratante de adultos, como por ellos mismos y sus cuidadores. Esta revisión ha sido elaborada con bibliografía de la base de datos PubMed desde 1977 a 2018 usando términos MeSH “spina bífida” y “urinary”, además de la experiencia chilena. Se describen las principales complicaciones del sistema urinario en pacientes adultos con espina bífida y sugerencias de su manejo.The patients with spina bifida may have multisistemic defects, mainly the urinary system. Population of adult patients with spina bifida has increased in last decades by the improved survival from pediatric age, emerging the need to know the management of these patients by clinicians, patients and their caregivers. This review was made with scientific articles available in PubMed database from 1977-2018 using search MeSH terms “spina bifida” and “urinary”, and the Chilean experience. Herein we discuss the main complications of urinary system of adult patients with spina bifida and their suggestive management

Consenso de la Rama de Genética de la Sociedad Chilena de Pediatría sobre las anomalías congénitas de mal pronóstico vital (ACMPV)

ResumenIntroducciónLa rama de genética de la Sociedad Chilena de Pediatría, en relación con el proyecto de ley que regula la despenalización de la interrupción voluntaria del embarazo en 3 causales, centrándose en la segunda causal que considera al «embrión o feto que padezca una alteración estructural congénita o genética incompatible con la vida extrauterina», se reunió para discutir conforme a la evidencia científica qué anomalías congénitas (AC) podrían ser incluidas en el proyecto de ley.MetodologíaLos expertos en genética clínica se centraron en 10 AC. Se efectuó revisión bibliográfica y una reunión extraordinaria para discutirla.ResultadosSe acordó no emplear el término «incompatible con la vida extrauterina», pues existen excepciones de sobrevidas más prolongadas y cambiar por «anomalía congénita de mal pronóstico vital (ACMPV)». Se evaluaron 10 AC: defectos graves de cierre del tubo neural: anencefalia, iniencefalia y craneorraquisquisis, hipoplasia pulmonar, feto acardio, ectopia cordis, triploidía no mosaico, complejo limb body wall, anomalía body stalk, trisomía 13, trisomía 18 y agenesia renal bilateral. Se analizaron los hallazgos sobre prevalencia, historia natural, métodos diagnósticos prenatales, sobrevida, casos descritos de sobrevida prolongada. Para catalogarlas como ACMPV se consideraron: sobrevida posnatal, existencia de tratamientos y evolución posterior e historia natural sin intervenciones.ConclusiónLas ACMPV incluidas serían: anencefalia, hipoplasia pulmonar severa, feto acardio, ectopia cordis cervical, triploidía no mosaico, complejo limb body wall, anomalía body stalk, trisomía 13 no mosaico, trisomía 18 no mosaico y agenesia renal bilateral. Se requiere para el diagnóstico que toda mujer gestante tenga acceso a evaluaciones ecográficas de anatomía fetal, y en ocasiones a resonancia magnética y estudios citogenéticos y moleculares.AbstractIntroductionThe Genetic Branch of the Chilean Society of Paediatrics, given the draft Law governing the decriminalisation of abortion on three grounds, focusing on the second ground, which considers the “embryo or foetus suffering from a congenital structural anomaly or a genetic disorder incompatible with life outside the womb”, met to discuss the scientific evidence according to which congenital anomalies (CA) may be included in this draft law.MethodologyExperts in clinical genetics focused on 10 CA, reviewed the literature evidence, and met to discuss it.ResultsIt was agreed not to use the term “incompatible with life outside the womb”, as there are exceptions and longer survivals, and change to “congenital anomaly of poor prognosis (CAPP)”. Ten CA were evaluated: serious defects of neural tube closure: anencephaly, iniencephaly and craniorachischisis, pulmonary hypoplasia, acardiac foetus, ectopia cordis, non-mosaic triploidy, “limb body wall” complex, “body stalk” anomaly, trisomy 13, trisomy 18, and bilateral renal agenesis. Findings on the prevalence, natural history, prenatal diagnostic methods, survival, and reported cases of prolonged survival were analysed. Post-natal survival, existence of treatments, and outcomes, as well as natural history without intervention, were taken into account in classifying a CA as a CAPP.ConclusionA CAPP would be: anencephaly, severe pulmonary hypoplasia, acardiac foetus, cervical ectopia cordis, non-mosaic triploidy, limb body wall complex, body stalk anomaly, non-mosaic trisomy 13, non-mosaic trisomy 18, and bilateral renal agenesis. For their diagnosis, it is required that all pregnant women have access to assessments by foetal anatomy ultrasound and occasionally MRI, and cytogenetic and molecular testing

The impact of leaving group anomericity on the structure of glycosyl cations of protected galactosides

It has been reported that fragments produced by glycosidic bond breakage in mass spectrometry‐based experiments can retain a memory of their anomeric configuration, which has major implications for glycan sequencing. Herein, we use cryogenic vibrational spectroscopy and ion mobility‐mass spectrometry to study the structure of B‐type fragments of protected galactosides. Cationic fragments were generated from glycosyl donors carrying trichloroacetimidate or thioethyl leaving groups of different anomeric configuration. The obtained infrared signatures indicate that the investigated fragments exhibit an identical structure, which suggests that there is no anomeric memory in B‐type ions of fully protected monosaccharides

Glycoside hydrolase from the GH76 family indicates that marine Salegentibacter sp. Hel_I_6 consumes alpha-mannan from fungi

Microbial glycan degradation is essential to global carbon cycling. The marine bacterium Salegentibacter sp. Hel_I_6 (Bacteroidota) isolated from seawater off Helgoland island (North Sea) contains an α-mannan inducible gene cluster with a GH76 family endo-α-1,6-mannanase (ShGH76). This cluster is related to genetic loci employed by human gut bacteria to digest fungal α-mannan. Metagenomes from the Hel_I_6 isolation site revealed increasing GH76 gene frequencies in free-living bacteria during microalgae blooms, suggesting degradation of α-1,6-mannans from fungi. Recombinant ShGH76 protein activity assays with yeast α-mannan and synthetic oligomannans showed endo-α-1,6-mannanase activity. Resolved structures of apo-ShGH76 (2.0 Å) and of mutants co-crystalized with fungal mannan-mimicking α-1,6-mannotetrose (1.90 Å) and α-1,6-mannotriose (1.47 Å) retained the canonical (α/α)6 fold, despite low identities with sequences of known GH76 structures (GH76s from gut bacteria: <27%). The apo-form active site differed from those known from gut bacteria, and co-crystallizations revealed a kinked oligomannan conformation. Co-crystallizations also revealed precise molecular-scale interactions of ShGH76 with fungal mannan-mimicking oligomannans, indicating adaptation to this particular type of substrate. Our data hence suggest presence of yet unknown fungal α-1,6-mannans in marine ecosystems, in particular during microalgal blooms