Efecto de coyolillo (Cyperus rotundus) sobre el crecimiento de canavalia (Canavalia ensiformis).

Durante el verano de 1995, en la Estación Experimental y de Prácticas de la Facultad de Agronomía de la Universidad de El Salvador, se estableció un ensayo intercalando Canavalia (0,80 m x 0,50m) y maíz (0,80 m x 0,30 m) bajo labranza cero. El lote sedividió en una parte con alta infestación de coyolillo y otra con predominio de malezas de hoja ancha como: Baltimora recta, Melantera sp., Lantana camara y Panicum sp. (No se hizo control de malezas). Se muestreó cada 10 días, utilizando 10 plantas de Canavalia por muestra, estudiando las variables: altura de planta, peso seco, tasa de crecimiento absoluto y tasa media de crecimiento relativo. La infestación de Cyperus inicialmente varió entre 1200 a 1650 plántulas de rebrote/m2. El ensayo se analizó como parcelas apareadas. Los resultados indican que para altura de plantas de Canavalia existieron diferencias significativas desde los 10 dds, incrementándose a los 20 y 30 dds; alcanzando mayor crecimiento bajo ausencia de Cyperus; logrando a los 40 dds, los 108 cm de altura; en contraste con la vecindad de Cyperus, cuya máxima altura fue 82,9 cm. Se demostró una competencia desfavorable a Canavalia, reflejándose también en la acumulación de materia seca

Novel Bifunctional Acylase from Actinoplanes utahensis: A Versatile Enzyme to Synthesize Antimicrobial Compounds and Use in Quorum Quenching Processes

Many intercellular communication processes, known as quorum sensing (QS), are regulated by the autoinducers N-acyl-L-homoserine lactones (AHLs) in Gram-negative bacteria. The inactivation of these QS processes using different quorum quenching (QQ) strategies, such as enzymatic degradation of the autoinducers or the receptor blocking with non-active analogs, could be the basis for the development of new antimicrobials. This study details the heterologous expression, purification, and characterization of a novel N-acylhomoserine lactone acylase from Actinoplanes utahensis NRRL 12052 (AuAHLA), which can hydrolyze different natural penicillins and N-acyl-homoserine lactones (with or without 3-oxo substitution), as well as synthesize them. Kinetic parameters for the hydrolysis of a broad range of substrates have shown that AuAHLA prefers penicillin V, followed by C12-HSL. In addition, AuAHLA inhibits the production of violacein by Chromobacterium violaceum CV026, confirming its potential use as a QQ agent. Noteworthy, AuAHLA is also able to efficiently synthesize penicillin V, besides natural AHLs and phenoxyacetyl-homoserine lactone (POHL), a nonnatural analog of AHLs that could be used to block QS receptors and inhibit signal of autoinducers, being the first reported AHL acylase capable of synthesizing AHLs

Acylase enzymes disrupting quorum sensing alter the transcriptome and phenotype of Pseudomonas aeruginosa, and the composition of bacterial biofilms from wastewater treatment plants

Biofilms represent an essential way of life and colonization of new environments for microorganisms. This feature is regulated by quorum sensing (QS), a microbial communication system based on autoinducer molecules, such as N-acyl-homoserine lactones (AHLs) in Gram negative bacteria. In artificial ecosystems, like Wastewater Treatment Plants (WWTPs), biofilm attachment in filtration membranes produces biofouling. In this environment, the microbial communities are mostly composed of Gram-negative phyla. Thus, we used two AHLs-degrading enzymes, obtained from Actinoplanes utahensis (namely AuAAC and AuAHLA) to determine the effects of degradation of QS signals in the biofilm formation, among other virulence factors, of a Pseudomonas aeruginosa strain isolated from a WWTP, assessing molecular mechanisms through transcriptomics. Besides, we studied the possible effects on community composition in biofilms from activated sludge samples. Although the studied enzymes only degraded the AHLs involved in one of the four QS systems of P. aeruginosa, these activities produced the deregulation of the complete QS network. In fact, AuAAC -the enzyme with higher catalytic efficiency- deregulated all the four QS systems. However, both enzymes reduced the biofilm formation and pyocyanin and protease production. The transcriptomic response of P. aeruginosa affected QS related genes, moreover, transcriptomic response to AuAAC affected mainly to QS related genes. Regarding community composition of biofilms, as expected, the abundance of Gram-negative phyla was significantly decreased after enzymatic treatment. These results support the potential use of such AHLs-degrading enzymes as a method to reduce biofilm formation in WWTP membranes and ameliorate bacterial virulence

A Novel Lipase from Streptomyces exfoliatus DSMZ 41693 for Biotechnological Applications

Genome mining of Streptomyces exfoliatus DSMZ 41693 has allowed us to identify four different lipase-encoding sequences, and one of them (SeLipC) has been successfully cloned and extracellularly expressed using Rhodococcus sp. T104 as a host. SeLipC was purified by one-step hydrophobic interaction chromatography. The enzyme is a monomeric protein of 27.6 kDa, which belongs to subfamily I.7 of lipolytic enzymes according to its phylogenetic analysis and biochemical characterization. The purified enzyme shows the highest activity at 60 °C and an optimum pH of 8.5, whereas thermal stability is significantly improved when protein concentration is increased, as confirmed by thermal deactivation kinetics, circular dichroism, and differential scanning calorimetry. Enzyme hydrolytic activity using p-nitrophenyl palmitate (pNPP) as substrate can be modulated by different water-miscible organic cosolvents, detergents, and metal ions. Likewise, kinetic parameters for pNPP are: KM = 49.6 µM, kcat = 57 s−1, and kcat/KM = 1.15 × 106 s−1·M−1. SeLipC is also able to hydrolyze olive oil and degrade several polyester-type polymers such as poly(butylene succinate) (PBS), poly(butylene succinate)-co-(butylene adipate) (PBSA), and poly(ε-caprolactone) (PCL). Moreover, SeLipC can catalyze the synthesis of different sugar fatty acid esters by transesterification using vinyl laurate as an acyl donor, demonstrating its interest in different biotechnological applications.This research was funded by the Ministerio de Ciencia, Innovación y Universidades of Spain, grants RTI2018-096037B-I00, TED2021-131462B-I00, TED2021-130430B-C21, and PDC2022-133817-I00.Peer reviewe

Homérica: estudiar y vivir el mundo griego II

Depto. de Filología ClásicaFac. de FilologíaFALSEsubmitte

Role of age and comorbidities in mortality of patients with infective endocarditis

[Purpose]: The aim of this study was to analyse the characteristics of patients with IE in three groups of age and to assess the ability of age and the Charlson Comorbidity Index (CCI) to predict mortality. [Methods]: Prospective cohort study of all patients with IE included in the GAMES Spanish database between 2008 and 2015.Patients were stratified into three age groups:<65 years,65 to 80 years,and ≥ 80 years.The area under the receiver-operating characteristic (AUROC) curve was calculated to quantify the diagnostic accuracy of the CCI to predict mortality risk. [Results]: A total of 3120 patients with IE (1327 < 65 years;1291 65-80 years;502 ≥ 80 years) were enrolled.Fever and heart failure were the most common presentations of IE, with no differences among age groups.Patients ≥80 years who underwent surgery were significantly lower compared with other age groups (14.3%,65 years; 20.5%,65-79 years; 31.3%,≥80 years). In-hospital mortality was lower in the <65-year group (20.3%,<65 years;30.1%,65-79 years;34.7%,≥80 years;p < 0.001) as well as 1-year mortality (3.2%, <65 years; 5.5%, 65-80 years;7.6%,≥80 years; p = 0.003).Independent predictors of mortality were age ≥ 80 years (hazard ratio [HR]:2.78;95% confidence interval [CI]:2.32–3.34), CCI ≥ 3 (HR:1.62; 95% CI:1.39–1.88),and non-performed surgery (HR:1.64;95% CI:11.16–1.58).When the three age groups were compared,the AUROC curve for CCI was significantly larger for patients aged <65 years(p < 0.001) for both in-hospital and 1-year mortality. [Conclusion]: There were no differences in the clinical presentation of IE between the groups. Age ≥ 80 years, high comorbidity (measured by CCI),and non-performance of surgery were independent predictors of mortality in patients with IE.CCI could help to identify those patients with IE and surgical indication who present a lower risk of in-hospital and 1-year mortality after surgery, especially in the <65-year group

Post-Franco Theatre

In the multiple realms and layers that comprise the contemporary Spanish theatrical landscape, “crisis” would seem to be the word that most often lingers in the air, as though it were a common mantra, ready to roll off the tongue of so many theatre professionals with such enormous ease, and even enthusiasm, that one is prompted to wonder whether it might indeed be a miracle that the contemporary technological revolution – coupled with perpetual quandaries concerning public and private funding for the arts – had not by now brought an end to the evolution of the oldest of live arts, or, at the very least, an end to drama as we know it

Nurses' perceptions of aids and obstacles to the provision of optimal end of life care in ICU

Contains fulltext : 172380.pdf (publisher's version ) (Open Access

Novel Bifunctional Acylase from Actinoplanes utahensis: A Versatile Enzyme to Synthesize Antimicrobial Compounds and Use in Quorum Quenching Processes

Many intercellular communication processes, known as quorum sensing (QS), are regulated by the autoinducers N-acyl-l-homoserine lactones (AHLs) in Gram-negative bacteria. The inactivation of these QS processes using different quorum quenching (QQ) strategies, such as enzymatic degradation of the autoinducers or the receptor blocking with non-active analogs, could be the basis for the development of new antimicrobials. This study details the heterologous expression, purification, and characterization of a novel N-acylhomoserine lactone acylase from Actinoplanes utahensis NRRL 12052 (AuAHLA), which can hydrolyze different natural penicillins and N-acyl-homoserine lactones (with or without 3-oxo substitution), as well as synthesize them. Kinetic parameters for the hydrolysis of a broad range of substrates have shown that AuAHLA prefers penicillin V, followed by C12-HSL. In addition, AuAHLA inhibits the production of violacein by Chromobacterium violaceum CV026, confirming its potential use as a QQ agent. Noteworthy, AuAHLA is also able to efficiently synthesize penicillin V, besides natural AHLs and phenoxyacetyl-homoserine lactone (POHL), a non-natural analog of AHLs that could be used to block QS receptors and inhibit signal of autoinducers, being the first reported AHL acylase capable of synthesizing AHLs

N-acilhomoserina lactona acilasa de Actinoplanes utahensis: caracterización e interés biotecnológico

Tesis inédita de la Universidad Complutense de Madrid, Facultad de Ciencias Biológicas, leída el 30-09-2021Las N-acilhomoserina lactonas (AHLs) son moléculas señalizadoras implicadas en los mecanismos de comunicación intercelular, conocidos como Quorum Sensing (QS), en bacterias Gram negativas. Estos mecanismos de QS tienen un papel fundamental en la sincronización de la expresión génica dentro de comunidades bacterianas, permitiéndoles responder de manera dependiente de la densidad celular a cambios en el ambiente. Diversas funciones biológicas como formación de biofilms, producción de factores de virulencia, síntesis de antibióticos, bioluminiscencia o transferencia de material genético están reguladas mediante QS. La interferencia del QS, o Quorum Quenching (QQ), se presenta como una interesante terapia antimicrobiana alternativa al uso antibióticos para inhibir los mecanismos de virulencia de bacterias patógenas sin afectar directamente a su crecimiento celular. Entre las diferentes estrategias de QQ que se pueden utilizar se encuentra la degradación o modificación enzimática de los autoinductores y entre las enzimas capaces de degradar AHLs se encuentran las acilasas...N-acyl-L-homoserine lactones (AHLs) are small signal molecules involved in intercellular communication processes, known as quorum sensing (QS), in Gram-negative bacteria. QS allows a bacterial community to synchronize the expression of a set of target genes in order to respond to environmental changes in a density-dependent manner. Several biological functions such as antibiotic production, secretion of virulence factors, biofilm formation, bioluminescence or conjugation are regulated by this mechanism. QS interference processes, known as Quorum Quenching (QQ), are an alternative antimicrobial therapy for inhibiting virulence mechanisms of pathogenic bacteria without affecting cell growth. One of the QQ strategies consists in the enzymatic degradation or modification of the autoinducers, being acylases one of the main groups of AHL degrading enzymes...Fac. de Ciencias BiológicasTRUEunpu