Summary
Bacterial chemotaxis is an adaptive behaviour, which requires sophisticated information‐processing capabilities that cause motile bacteria to either move towards or flee from chemicals. ...Pseudomonas putida DOT‐T1E exhibits the capability to move towards different aromatic hydrocarbons present at a wide range of concentrations. The chemotactic response is mediated by the McpT chemoreceptor encoded by the pGRT1 megaplasmid. Two alleles of mcpT are borne on this plasmid and inactivation of either one led to loss of this chemotactic phenotype. Cloning of mcpT into a plasmid complemented not only the mcpT mutants but also its transfer to other Pseudomonas conferred chemotactic response to high concentrations of toluene and other chemicals. Therefore, the phenomenon of chemotaxis towards toxic compounds at high concentrations is gene‐dose dependent. In vitro experiments show that McpT is methylated by CheR and McpT net methylation was diminished in the presence of hydrocarbons, what influences chemotactic movement towards these chemicals.
Diversity at its best: bacterial taxis Krell, Tino; Lacal, Jesús; Muñoz-Martínez, Francisco ...
Environmental microbiology,
20/May , Volume:
13, Issue:
5
Journal Article
Peer reviewed
Open access
Bacterial taxis is one of the most investigated signal transduction mechanisms. Studies of taxis have primarily used Escherichia coli and Salmonella as model organism. However, more recent studies of ...other bacterial species revealed a significant diversity in the chemotaxis mechanisms which are reviewed here. Differences include the genomic abundance, size and topology of chemoreceptors, the mode of signal binding, the presence of additional cytoplasmic signal transduction proteins or the motor mechanism. This diversity of chemotactic mechanisms is partly due to the diverse nature of input signals. However, the physiological reasons for the majority of differences in the taxis systems are poorly understood and its elucidation represents a major research need.
En este trabajo se presenta resultados sobre la evaluación de la resistencia/peso en una viga tipo I de material compuesto híbrido con fibras de algodón/vidrio (64% fibras de algodón y 36% fibras de ...vidrio). Se realizaron simulaciones numéricas a flexión a través del programa ANSYS y una prueba experimental a flexión en la máquina de ensayos Shimadzu AG-Xplus 100kN. Los resultados mostraron que es posible obtener una geometría optimizada dentro de la viga a través de la remoción estratégica de zonas de material sin comprometer la integridad estructural. Además, la prueba experimental a flexión en la viga de material compuesto mostró un valor superior en la relación de resistencia/peso (44) en comparación con la viga optimizada de aluminio 6061-T6 (39.65); este comportamiento se atribuye a que los materiales compuestos reforzados con fibras son generalmente menos densos en comparación con los metales, y a la distribución de las fibras de algodón y vidrio dentro de la viga.
Challenges to Legal Theory offers the reader a fascinating journey through a variety of multi-disciplinary topics, ranging from law and literature, and law and religion, to legal philosophy and ...constitutional law. The collection reflects some of the challenges that the field of legal theory currently faces. It is compiled by a selection of international and Spanish scholars, whose essays are made available in English translation for the first time. The volume is based on a collection of essays, published in Spanish, in honour of Professor José Iturmendi Morales, of Complutense University, Madrid, and brings the rich scholarship of pre-eminent Spanish scholars of law and legal theory to an international audience.
Este artículo trata de afrontar el alcance de la razón pública en el mundo actual donde la diversidad cultural es un hecho reconocido o, cuando menos, en vías de reconocimiento. Parte del proceso ...histórico de conformación social racional que ha consolidado el espacio político y la vida pública para evidenciar sus deficiencias, limitaciones y distorsiones en relación con la complejidad cultural humana. Destaca que su carácter transformador de la vida social, tendente a la consolidación racional de un espacio público homogéneo, margina el sentido originario del derecho y la moral que dotaban de legitimidad a los grupos humanos comunitarios con cultura propia y obstruye su supervivencia. Para resolver el papel legítimo en la vida social de las comunidades culturales, en desventaja respecto a la razón dominante en el espacio público, propone un derecho universalista que posibilite el bien común y la prestación comunitaria de servicios, en términos más empresariales que políticos.
Magnetic actuators, magnetic gears, vibrational energy harvesters and other micro-electromagnetic devices requires micro-magnetic rotors with alternant magnetizations to optimize their performance. ...Different approaches have been used for multipole magnetization of micro-magnets like fixed micro-fixtures, thermomagnetic patterning or laser machining. The main limitation of the previous techniques is that the inversion of the magnetic polarizations is only partially done. In this work, a concept based on 2D multipole magnetization printing of micro-magnets is proposed and analyzed to overcome current limitations. The fixtures are designed to be printed on a standard 35 μm PCB. The dependence of the magnetizing field with respect to the geometrical parameter of the fixture is analyzed. Maps of the required current for the magnetizing fields are also given. Some design recommendations to optimize the magnetizing field and to minimize current, thus the heat, are given.
In this paper, a parallel computing method is proposed to perform the background denoising and wheezing detection from a multi-channel recording captured during the auscultation process. The proposed ...system is based on a non-negative matrix factorization (NMF) approach and a detection strategy. Moreover, the initialization of the proposed model is based on singular value decomposition to avoid dependence on the initial values of the NMF parameters. Additionally, novel update rules to simultaneously address the multichannel denoising while preserving an orthogonal constraint to maximize source separation have been designed. The proposed system has been evaluated for the task of wheezing detection showing a significant improvement over state-of-the-art algorithms when noisy sound sources are present. Moreover, parallel and high-performance techniques have been used to speedup the execution of the proposed system, showing that it is possible to achieve fast execution times, which enables its implementation in real-world scenarios.
In this work, the strength-to-weight ratio on I-beam of a cotton-glass fibers hybrid composite (64% cotton fibers and 36% glass fibers) was assessed. Numerical simulations were carried out under ...flexural loads and a flexural test were carried out using a Shimadzu AG-X plus 100kN testing machine. The results showed that it is possible to obtain an optimized geometry within the beam through the strategic removal of material zones without compromising the structural integrity. Furthermore, the flexural test on the composite beam showed a higher value in the strength/weight ratio (44) compared to the optimized 6061-T6 aluminum beam (39.65); this behavior can be explained because fiber-reinforced composites are generally less dense compared to metals, and to the distribution of cotton and glass fibers within the beam.
En este trabajo se presenta resultados sobre la evaluación de la resistencia/peso en una viga tipo I de material compuesto híbrido con fibras de algodón/vidrio (64% fibras de algodón y 36% fibras de vidrio). Se realizaron simulaciones numéricas a flexión a través del programa ANSYS y una prueba experimental a flexión en la máquina de ensayos Shimadzu AG-Xplus 100kN. Los resultados mostraron que es posible obtener una geometría optimizada dentro de la viga a través de la remoción estratégica de zonas de material sin comprometer la integridad estructural. Además, la prueba experimental a flexión en la viga de material compuesto mostró un valor superior en la relación de resistencia/peso (44) en comparación con la viga optimizada de aluminio 6061-T6 (39.65); este comportamiento se atribuye a que los materiales compuestos reforzados con fibras son generalmente menos densos en comparación con los metales, y a la distribución de las fibras de algodón y vidrio dentro de la viga.
Background & Aims
Information about the impact of severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) in patients with liver cancer is lacking. This study characterizes the outcomes and ...mortality risk in this population.
Methods
Multicentre retrospective, cross‐sectional, international study of liver cancer patients with SARS‐CoV‐2 infection registered between February and December 2020. Clinical data at SARS‐CoV‐2 diagnosis and outcomes were registered.
Results
Two hundred fifty patients from 38 centres were included, 218 with hepatocellular carcinoma (HCC) and 32 with intrahepatic cholangiocarcinoma (iCCA). The median age was 66.5 and 64.5 years, and 84.9% and 21.9% had cirrhosis in the HCC and iCCA cohorts respectively. Patients had advanced cancer stage at SARS‐CoV‐2 diagnosis in 39.0% of the HCC and 71.9% of the iCCA patients. After a median follow‐up of 7.20 (IQR: 1.84–11.24) months, 100 (40%) patients have died, 48% of the deaths were SARS‐CoV‐2‐related. Forty (18.4%) HCC patients died within 30‐days. The death rate increase was significantly different according to the BCLC stage (6.10% 95% CI 2.24–12.74, 11.76% 95% CI 4.73–22.30, 20.69% 95% CI 11.35–31.96 and 34.52% 95% CI 17.03–52.78 for BCLC 0/A, B, C and D, respectively; p = .0017). The hazard ratio was 1.45 (95% CI 0.49–4.31; p = .5032) in BCLC‐B versus 0/A, and 3.13 (95% CI 1.29–7.62; p = .0118) in BCLC‐C versus 0/A in the competing risk Cox regression model. Nineteen out of 32 iCCA (59.4%) died, and 12 deaths were related to SARS‐CoV‐2 infection.
Conclusions
This is the largest cohort of liver cancer patients infected with SARS‐CoV‐2. It characterizes the 30‐day mortality risk of SARS‐CoV‐2 infected patients with HCC during this period.
High Specificity in CheR Methyltransferase Function García-Fontana, Cristina; Reyes-Darias, José Antonio; Muñoz-Martínez, Francisco ...
Journal of biological chemistry/The Journal of biological chemistry,
06/2013, Volume:
288, Issue:
26
Journal Article
Peer reviewed
Open access
Chemosensory pathways are a major signal transduction mechanism in bacteria. CheR methyltransferases catalyze the methylation of the cytosolic signaling domain of chemoreceptors and are among the ...core proteins of chemosensory cascades. These enzymes have primarily been studied Escherichia coli and Salmonella typhimurium, which possess a single CheR involved in chemotaxis. Many other bacteria possess multiple cheR genes. Because the sequences of chemoreceptor signaling domains are highly conserved, it remains to be established with what degree of specificity CheR paralogues exert their activity. We report here a comparative analysis of the three CheR paralogues of Pseudomonas putida. Isothermal titration calorimetry studies show that these paralogues bind the product of the methylation reaction, S-adenosylhomocysteine, with much higher affinity (KD of 0.14–2.2 μm) than the substrate S-adenosylmethionine (KD of 22–43 μm), which indicates product feedback inhibition. Product binding was particularly tight for CheR2. Analytical ultracentrifugation experiments demonstrate that CheR2 is monomeric in the absence and presence of S-adenosylmethionine or S-adenosylhomocysteine. Methylation assays show that CheR2, but not the other paralogues, methylates the McpS and McpT chemotaxis receptors. The mutant in CheR2 was deficient in chemotaxis, whereas mutation of CheR1 and CheR3 had either no or little effect on chemotaxis. In contrast, biofilm formation of the CheR1 mutant was largely impaired but not affected in the other mutants. We conclude that CheR2 forms part of a chemotaxis pathway, and CheR1 forms part of a chemosensory route that controls biofilm formation. Data suggest that CheR methyltransferases act with high specificity on their cognate chemoreceptors.
Background: Many bacteria possess multiple CheR methyltransferases that methylate the conserved chemoreceptor signaling domains.
Results: CheR2 of Pseudomonas putida is essential for chemotaxis, whereas CheR1 is required for efficient biofilm formation, and only CheR2 methylates chemotaxis receptors McpS and McpT.
Conclusion: Paralogous CheR have different functions.
Significance: CheR have evolved to specifically recognize cognate chemoreceptors.
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