Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 60
Filtrar
Más filtros

Tipo del documento
Intervalo de año de publicación
1.
Sensors (Basel) ; 24(9)2024 Apr 27.
Artículo en Inglés | MEDLINE | ID: mdl-38732907

RESUMEN

This paper addresses the issue of LED short-circuit fault detection in signaling and lighting systems in the automotive industry. The conventional diagnostic method commonly implemented in newer vehicles relies on measuring the voltage drop across different LED branches and comparing it with threshold values indicating faults caused by open circuits or LED short circuits. With this algorithm, detecting cases of a few LEDs short-circuited within a branch, particularly a single malfunctioning LED, is particularly challenging. In this work, two easily implementable algorithms are proposed to address this issue within the vehicle's control unit. One is based on a mathematical prediction model, while the other utilizes a neural network. The results obtained offer a 100% LED short-circuit fault detection rate in the majority of analyzed cases, representing a significant improvement over the conventional method, even in scenarios involving a single malfunctioning LED within a branch. Additionally, the neural network-based model can accurately predict the number of failed LEDs.

2.
Sensors (Basel) ; 23(13)2023 Jun 29.
Artículo en Inglés | MEDLINE | ID: mdl-37447871

RESUMEN

The world of elite sports has always been characterized by intense competition, where victories are often determined by minimal differences. This means that every little detail in the preparation of top-level athletes is crucial to their performance at the highest level. One of the most significant aspects to monitor is the jumping capacity, as it enables the measurement of performance, progression, and helps prevent injuries. Herein, we present the development of a system capable of measuring the flight time and height reached by the user, reporting the results through a smartphone using an Android ad-hoc application, which handles all the data processing. The system consists of an affordable and portable circuit based on an accelerometer. It communicates with the smartphone via UART using a Bluetooth module, and its battery provides approximately 9 h of autonomy, making it suitable for outdoor operations. To evaluate the system's precision, we conducted performance tests (counter-movement jumps) with seven subjects. The results confirmed the system's potential for monitoring high-level sports training sessions, as the average deviation obtained was only 2.1% (~0.01 s) in the analysis of flight time and 4.6% (~0.01 m) in jump height.


Asunto(s)
Rendimiento Atlético , Deportes , Humanos , Movimiento , Teléfono Inteligente , Fenómenos Biomecánicos
3.
J Phys Chem A ; 126(40): 7230-7241, 2022 Oct 13.
Artículo en Inglés | MEDLINE | ID: mdl-36178377

RESUMEN

Two ketones of atmospheric interest, methyl glyoxal and methyl vinyl ketone, are studied using explicitly correlated coupled cluster theory and core-valence correlation-consistent basis sets. The work focuses on the far-infrared region. At the employed level of theory, the rotational constants can be determined to within a few megahertz of the experimental data. Both molecules present two conformers, trans/cis and antiperiplanar (Ap)/synperiplanar (Sp), respectively. trans-Methyl glyoxal and Ap-methyl vinyl ketone are the preferred structures. cis-Methyl glyoxal is a secondary minimum of very low stability, which justifies the unavailability of experimental data in this form. In methyl vinyl ketone, the two conformers are almost isoenergetic, but the interconversion implies a relatively high torsional barrier of 1798 cm-1. A very low methyl torsional barrier was estimated for trans-methyl glyoxal (V3 = 273.6 cm-1). Barriers of 429.6 and 380.7 cm-1 were computed for Ap- and Sp-methyl vinyl ketone. Vibrational second-order perturbation theory was applied to determine the rovibrational parameters. The far-infrared region was explored using a variational procedure of reduced dimensionality. For trans-methyl glyoxal, the ground vibrational state was estimated to split by 0.067 cm-1, and the two low excited energy levels (1 0) and (0 1) were found to lie at 89.588 cm-1/88.683 cm-1 (A2/E) and 124.636 cm-1/123.785 cm-1 (A2/E). For Ap- and Sp-methyl vinyl ketone, the ground vibrational state splittings were estimated to be 0.008 and 0.017 cm-1, respectively.

4.
Sensors (Basel) ; 22(11)2022 May 28.
Artículo en Inglés | MEDLINE | ID: mdl-35684732

RESUMEN

In this work, we present a ballistocardiographic (BCG) system for the determination of heart and breath rates and activity of a user lying in bed. Our primary goal was to simplify the analog and digital processing usually required in these kinds of systems while retaining high performance. A novel sensing approach is proposed consisting of a white LED facing a digital light detector. This detector provides precise measurements of the variations of the light intensity of the incident light due to the vibrations of the bed produced by the subject's breathing, heartbeat, or activity. Four small springs, acting as a bandpass filter, connect the boards where the LED and the detector are mounted. Owing to the mechanical bandpass filtering caused by the compressed springs, the proposed system generates a BCG signal that reflects the main frequencies of the heartbeat, breathing, and movement of the lying subject. Without requiring any analog signal processing, this device continuously transmits the measurements to a microcontroller through a two-wire communication protocol, where they are processed to provide an estimation of the parameters of interest in configurable time intervals. The final information of interest is wirelessly sent to the user's smartphone by means of a Bluetooth connection. For evaluation purposes, the proposed system has been compared with typical BCG systems showing excellent performance for different subject positions. Moreover, applied postprocessing methods have shown good behavior for information separation from a single-channel signal. Therefore, the determination of the heart rate, breathing rate, and activity of the patient is achieved through a highly simplified signal processing without any need for analog signal conditioning.


Asunto(s)
Balistocardiografía , Humanos , Balistocardiografía/métodos , Frecuencia Cardíaca/fisiología , Procesamiento de Señales Asistido por Computador , Sueño
5.
J Biol Chem ; 295(32): 10969-10987, 2020 08 07.
Artículo en Inglés | MEDLINE | ID: mdl-32546484

RESUMEN

Rhizobia are soil bacteria that form important symbiotic associations with legumes, and rhizobial surface polysaccharides, such as K-antigen polysaccharide (KPS) and lipopolysaccharide (LPS), might be important for symbiosis. Previously, we obtained a mutant of Sinorhizobium fredii HH103, rkpA, that does not produce KPS, a homopolysaccharide of a pseudaminic acid derivative, but whose LPS electrophoretic profile was indistinguishable from that of the WT strain. We also previously demonstrated that the HH103 rkpLMNOPQ operon is responsible for 5-acetamido-3,5,7,9-tetradeoxy-7-(3-hydroxybutyramido)-l-glycero-l-manno-nonulosonic acid [Pse5NAc7(3OHBu)] production and is involved in HH103 KPS and LPS biosynthesis and that an HH103 rkpM mutant cannot produce KPS and displays an altered LPS structure. Here, we analyzed the LPS structure of HH103 rkpA, focusing on the carbohydrate portion, and found that it contains a highly heterogeneous lipid A and a peculiar core oligosaccharide composed of an unusually high number of hexuronic acids containing ß-configured Pse5NAc7(3OHBu). This pseudaminic acid derivative, in its α-configuration, was the only structural component of the S. fredii HH103 KPS and, to the best of our knowledge, has never been reported from any other rhizobial LPS. We also show that Pse5NAc7(3OHBu) is the complete or partial epitope for a mAb, NB6-228.22, that can recognize the HH103 LPS, but not those of most of the S. fredii strains tested here. We also show that the LPS from HH103 rkpM is identical to that of HH103 rkpA but devoid of any Pse5NAc7(3OHBu) residues. Notably, this rkpM mutant was severely impaired in symbiosis with its host, Macroptilium atropurpureum.


Asunto(s)
Glycine max/microbiología , Lipopolisacáridos/química , Sinorhizobium fredii/química , Simbiosis , Anticuerpos Monoclonales/inmunología , Antígenos Bacterianos/inmunología , Antígenos de Superficie/inmunología , Proteínas Bacterianas/genética , Conformación de Carbohidratos , Espectroscopía de Resonancia Magnética con Carbono-13 , Epítopos/inmunología , Lipopolisacáridos/inmunología , Espectroscopía de Protones por Resonancia Magnética , Sinorhizobium fredii/genética , Sinorhizobium fredii/inmunología , Espectrometría de Masa por Láser de Matriz Asistida de Ionización Desorción , Azúcares Ácidos/química
6.
Sensors (Basel) ; 21(7)2021 Apr 02.
Artículo en Inglés | MEDLINE | ID: mdl-33918498

RESUMEN

In skiing it is important to know how the skier accelerates and inclines the skis during the turn to avoid injuries and improve technique. The purpose of this pilot study with three participants was to develop and evaluate a compact, wireless, and low-cost system for detecting the inclination and acceleration of skis in the field based on inertial measurement units (IMU). To that end, a commercial IMU board was placed on each ski behind the skier boot. With the use of an attitude and heading reference system algorithm included in the sensor board, the orientation and attitude data of the skis were obtained (roll, pitch, and yaw) by IMU sensor data fusion. Results demonstrate that the proposed IMU-based system can provide reliable low-drifted data up to 11 min of continuous usage in the worst case. Inertial angle data from the IMU-based system were compared with the data collected by a video-based 3D-kinematic reference system to evaluate its operation in terms of data correlation and system performance. Correlation coefficients between 0.889 (roll) and 0.991 (yaw) were obtained. Mean biases from -1.13° (roll) to 0.44° (yaw) and 95% limits of agreements from 2.87° (yaw) to 6.27° (roll) were calculated for the 1-min trials. Although low mean biases were achieved, some limitations arose in the system precision for pitch and roll estimations that could be due to the low sampling rate allowed by the sensor data fusion algorithm and the initial zeroing of the gyroscope.


Asunto(s)
Esquí , Aceleración , Algoritmos , Fenómenos Biomecánicos , Humanos , Proyectos Piloto
7.
Environ Microbiol ; 22(3): 1104-1124, 2020 03.
Artículo en Inglés | MEDLINE | ID: mdl-31845498

RESUMEN

Sinorhizobium fredii HH103 RifR is a broad host-range rhizobial strain able to nodulate with soybean and Lotus burttii, but it is ineffective with L. japonicus. Here, we study the role of the HH103 RifR SyrM protein in the regulation of gene expression and its relevance in symbiosis with those three legumes. RNAseq analyses show that HH103 SyrM is an important transcriptional regulator not only in the presence of inducer flavonoids but also in its absence. Lack of SyrM increases Nod factors production and decreases genistein-mediated repression of exopolysaccharide production in HH103. In symbiosis, mutation of syrM partially impaired interaction with soybean but improves effectiveness with L. burttii and extends the host-rage to L. japonicus Gifu. In addition, HH103 syrM mutants enter in both Lotus species by infection threads, whereas HH103 uses the more primitive intercellular infection to enter into L. burttii roots These symbiotic phenotypes were previously observed in two other HH103 mutants affected in symbiotic regulators, nodD2 and nolR, revealing that in S. fredii HH103 numerous transcriptional regulators finely modulate symbiotic gene expression.


Asunto(s)
Genes Bacterianos/genética , Glycine max/microbiología , Lotus/microbiología , Nodulación de la Raíz de la Planta/genética , Simbiosis/genética , Proteínas Bacterianas/metabolismo , Silenciador del Gen , Especificidad del Huésped/genética , Mutación , Fenotipo , Raíces de Plantas/metabolismo , Rhizobium/genética , Sinorhizobium fredii/genética
8.
Sensors (Basel) ; 20(6)2020 Mar 11.
Artículo en Inglés | MEDLINE | ID: mdl-32168978

RESUMEN

Safe quality control of radiotherapy treatments lies in reliable dosimetric sensors. Currently, ionization chambers and solid-state diodes along with electrometers as readout systems are accomplishing this task. In this work, we present a well-known and low-cost semiconductor sensor, the light-dependent resistor (LDR), as an alternative to the existing sensing devices for dosimetry. To demonstrate this, a complete characterization of the response to radiation of commercial LDRs has been conducted in terms of sensitivity, reproducibility and thermal correction under different bias voltages. Irradiation sessions have been applied under the common conditions in radiotherapy treatments using a hospital linear accelerator. Moreover, the same electrometer used for the ionization chamber has also been successfully used for LDRs. In comparison with the sensitivity achieved for the ionization chamber (0.2 nC/cGy at 400 V bias voltage), higher sensitivities have been measured for the proposed LDRs, ranging from 0.24 to 1.04 nC/cGy at bias voltages from 30 to 150 V, with a reproducibility uncertainty among samples of around 10%. In addition, LDR temperature dependence has been properly modeled using the simple thermistor model so that an easy thermal drift correction of dose measurements can be applied. Therefore, experimental results show that LDRs can be a reliable alternative to dosimetric sensors with the advantages of low size, affordable cost and the fact that it could be adopted with minimal changes in routine dosimetry quality control since the same readout system is fully compatible.


Asunto(s)
Electrónica Médica/instrumentación , Radiometría/instrumentación , Dosificación Radioterapéutica , Equipos y Suministros Eléctricos , Electrónica Médica/normas , Diseño de Equipo , Luz , Modelos Biológicos , Sensibilidad y Especificidad , Temperatura
9.
Environ Microbiol ; 21(5): 1718-1739, 2019 05.
Artículo en Inglés | MEDLINE | ID: mdl-30839140

RESUMEN

Sinorhizobium fredii HH103 RifR , a broad-host-range rhizobial strain, forms ineffective nodules with Lotus japonicus but induces nitrogen-fixing nodules in Lotus burttii roots that are infected by intercellular entry. Here we show that HH103 RifR nolR or nodD2 mutants gain the ability to induce infection thread formation and to form nitrogen-fixing nodules in L. japonicus Gifu. Microscopy studies showed that the mode of infection of L. burttii roots by the nodD2 and nolR mutants switched from intercellular entry to infection threads (ITs). In the presence of the isoflavone genistein, both mutants overproduced Nod-factors. Transcriptomic analyses showed that, in the presence of Lotus japonicus Gifu root exudates, genes related to Nod factors production were overexpressed in both mutants in comparison to HH103 RifR . Complementation of the nodD2 and nolR mutants provoked a decrease in Nod-factor production, the incapacity to form nitrogen-fixing nodules with L. japonicus Gifu and restored the intercellular way of infection in L. burttii. Thus, the capacity of S. fredii HH103 RifR nodD2 and nolR mutants to infect L. burttii and L. japonicus Gifu by ITs and fix nitrogen L. japonicus Gifu might be correlated with Nod-factor overproduction, although other bacterial symbiotic signals could also be involved.


Asunto(s)
Lotus/microbiología , Enfermedades de las Plantas/microbiología , Sinorhizobium fredii/fisiología , Especificidad del Huésped , Mutación , Raíces de Plantas/microbiología , Sinorhizobium fredii/genética , Sinorhizobium fredii/aislamiento & purificación
10.
J Phys Chem A ; 123(44): 9544-9551, 2019 Nov 07.
Artículo en Inglés | MEDLINE | ID: mdl-31596086

RESUMEN

Recent works have shown that the spectroscopic access to highly excited states provides enough information to characterize transition states in isomerization reactions. Here, we show that information about the transition state of the bond-breaking HCN-HNC isomerization reaction can also be achieved with the two-dimensional limit of the algebraic vibron model. We describe the system's bending vibration with the algebraic Hamiltonian and use its classical limit to characterize the transition state. Using either the coherent state formalism or a recently proposed approach by Baraban [ Science 2015 , 350 , 1338 - 1342 ], we obtain an accurate description of the isomerization transition state. In addition, we show that the energy-level dynamics and the transition state wave function structure indicate that the spectrum in the vicinity of the isomerization saddle point can be understood in terms of the formalism for excited-state quantum phase transitions.

11.
Proc Natl Acad Sci U S A ; 112(7): E757-65, 2015 Feb 17.
Artículo en Inglés | MEDLINE | ID: mdl-25650430

RESUMEN

An artificial increase of cyclic diguanylate (c-di-GMP) levels in Sinorhizobium meliloti 8530, a bacterium that does not carry known cellulose synthesis genes, leads to overproduction of a substance that binds the dyes Congo red and calcofluor. Sugar composition and methylation analyses and NMR studies identified this compound as a linear mixed-linkage (1 → 3)(1 → 4)-ß-D-glucan (ML ß-glucan), not previously described in bacteria but resembling ML ß-glucans found in plants and lichens. This unique polymer is hydrolyzed by the specific endoglucanase lichenase, but, unlike lichenan and barley glucan, it generates a disaccharidic → 4)-ß-D-Glcp-(1 → 3)-ß-D-Glcp-(1 → repeating unit. A two-gene operon bgsBA required for production of this ML ß-glucan is conserved among several genera within the order Rhizobiales, where bgsA encodes a glycosyl transferase with domain resemblance and phylogenetic relationship to curdlan synthases and to bacterial cellulose synthases. ML ß-glucan synthesis is subjected to both transcriptional and posttranslational regulation. bgsBA transcription is dependent on the exopolysaccharide/quorum sensing ExpR/SinI regulatory system, and posttranslational regulation seems to involve allosteric activation of the ML ß-glucan synthase BgsA by c-di-GMP binding to its C-terminal domain. To our knowledge, this is the first report on a linear mixed-linkage (1 → 3)(1 → 4)-ß-glucan produced by a bacterium. The S. meliloti ML ß-glucan participates in bacterial aggregation and biofilm formation and is required for efficient attachment to the roots of a host plant, resembling the biological role of cellulose in other bacteria.


Asunto(s)
GMP Cíclico/análogos & derivados , Proteoglicanos/metabolismo , Receptores de Factores de Crecimiento Transformadores beta/metabolismo , Sinorhizobium meliloti/metabolismo , Secuencia de Carbohidratos , Cromatografía en Capa Delgada , GMP Cíclico/metabolismo , Medicago sativa/microbiología , Datos de Secuencia Molecular , Operón , Filogenia , Raíces de Plantas/microbiología , Reacción en Cadena de la Polimerasa , Proteoglicanos/química , Receptores de Factores de Crecimiento Transformadores beta/química , Sinorhizobium meliloti/genética , Transcripción Genética
12.
Mol Plant Microbe Interact ; 29(9): 700-712, 2016 09.
Artículo en Inglés | MEDLINE | ID: mdl-27482821

RESUMEN

Sinorhizobium fredii HH103 is a rhizobial strain showing a broad host range of nodulation. In addition to the induction of bacterial nodulation genes, transition from a free-living to a symbiotic state requires complex genetic expression changes with the participation of global regulators. We have analyzed the role of the zinc-finger transcriptional regulator MucR1 from S. fredii HH103 under both free-living conditions and symbiosis with two HH103 host plants, Glycine max and Lotus burttii. Inactivation of HH103 mucR1 led to a severe decrease in exopolysaccharide (EPS) biosynthesis but enhanced production of external cyclic glucans (CG). This mutant also showed increased cell aggregation capacity as well as a drastic reduction in nitrogen-fixation capacity with G. max and L. burttii. However, in these two legumes, the number of nodules induced by the mucR1 mutant was significantly increased and decreased, respectively, with respect to the wild-type strain, indicating that MucR1 can differently affect nodulation depending on the host plant. RNA-Seq analysis carried out in the absence and the presence of flavonoids showed that MucR1 controls the expression of hundreds of genes (including some related to EPS production and CG transport), some of them being related to the nod regulon.


Asunto(s)
Proteínas Bacterianas/metabolismo , Glycine max/microbiología , Lotus/microbiología , Regulón/genética , Sinorhizobium fredii/fisiología , Simbiosis , Proteínas Bacterianas/genética , Flavonoides/metabolismo , Fijación del Nitrógeno , Nodulación de la Raíz de la Planta , Análisis de Secuencia de ARN , Sinorhizobium fredii/genética
13.
Mol Plant Microbe Interact ; 29(12): 925-937, 2016 12.
Artículo en Inglés | MEDLINE | ID: mdl-27827003

RESUMEN

Sinorhizobium fredii HH103-Rifr, a broad host range rhizobial strain, induces nitrogen-fixing nodules in Lotus burttii but ineffective nodules in L. japonicus. Confocal microscopy studies showed that Mesorhizobium loti MAFF303099 and S. fredii HH103-Rifr invade L. burttii roots through infection threads or epidermal cracks, respectively. Infection threads in root hairs were not observed in L. burttii plants inoculated with S. fredii HH103-Rifr. A S. fredii HH103-Rifr nodA mutant failed to nodulate L. burttii, demonstrating that Nod factors are strictly necessary for this crack-entry mode, and a noeL mutant was also severely impaired in L. burttii nodulation, indicating that the presence of fucosyl residues in the Nod factor is symbiotically relevant. However, significant symbiotic impacts due to the absence of methylation or to acetylation of the fucosyl residue were not detected. In contrast S. fredii HH103-Rifr mutants showing lipopolysaccharide alterations had reduced symbiotic capacity, while mutants affected in production of either exopolysaccharides, capsular polysaccharides, or both were not impaired in nodulation. Mutants unable to produce cyclic glucans and purine or pyrimidine auxotrophic mutants formed ineffective nodules with L. burttii. Flagellin-dependent bacterial mobility was not required for crack infection, since HH103-Rifr fla mutants nodulated L. burttii. None of the S. fredii HH103-Rifr surface-polysaccharide mutants gained effective nodulation with L. japonicus.


Asunto(s)
Lotus/microbiología , Polisacáridos Bacterianos/metabolismo , Sinorhizobium fredii/fisiología , Simbiosis , Proteínas Bacterianas/genética , Proteínas Bacterianas/metabolismo , Especificidad del Huésped , Lotus/citología , Lotus/fisiología , Mutación , Fenotipo , Nodulación de la Raíz de la Planta , Raíces de Plantas/citología , Raíces de Plantas/microbiología , Raíces de Plantas/fisiología , Polisacáridos Bacterianos/química , Purinas/metabolismo , Pirimidinas/metabolismo , Sinorhizobium fredii/citología , Sinorhizobium fredii/genética
14.
Sensors (Basel) ; 16(7)2016 Jul 14.
Artículo en Inglés | MEDLINE | ID: mdl-27428973

RESUMEN

This work presents the design, fabrication, and characterization of a passive printed radiofrequency identification tag in the ultra-high-frequency band with multiple optical sensing capabilities. This tag includes five photodiodes to cover a wide spectral range from near-infrared to visible and ultraviolet spectral regions. The tag antenna and circuit connections have been screen-printed on a flexible polymeric substrate. An ultra-low-power microcontroller-based switch has been included to measure the five magnitudes issuing from the optical sensors, providing a spectral fingerprint of the incident electromagnetic radiation from ultraviolet to infrared, without requiring energy from a battery. The normalization procedure has been designed applying illuminants, and the entire system was tested by measuring cards from a colour chart and sensing fruit ripening.

15.
Int J Mol Sci ; 17(5)2016 May 18.
Artículo en Inglés | MEDLINE | ID: mdl-27213334

RESUMEN

Sinorhizobium (Ensifer) fredii (S. fredii) is a rhizobial species exhibiting a remarkably broad nodulation host-range. Thus, S. fredii is able to effectively nodulate dozens of different legumes, including plants forming determinate nodules, such as the important crops soybean and cowpea, and plants forming indeterminate nodules, such as Glycyrrhiza uralensis and pigeon-pea. This capacity of adaptation to different symbioses makes the study of the molecular signals produced by S. fredii strains of increasing interest since it allows the analysis of their symbiotic role in different types of nodule. In this review, we analyze in depth different S. fredii molecules that act as signals in symbiosis, including nodulation factors, different surface polysaccharides (exopolysaccharides, lipopolysaccharides, cyclic glucans, and K-antigen capsular polysaccharides), and effectors delivered to the interior of the host cells through a symbiotic type 3 secretion system.


Asunto(s)
Proteínas Bacterianas/metabolismo , Glycine max/microbiología , Sinorhizobium fredii/fisiología , Proteínas Bacterianas/química , Estructura Molecular , Nodulación de la Raíz de la Planta , Polisacáridos Bacterianos/metabolismo , Sinorhizobium fredii/metabolismo , Simbiosis , Sistemas de Secreción Tipo III
16.
BMC Genomics ; 16: 864, 2015 Oct 26.
Artículo en Inglés | MEDLINE | ID: mdl-26502986

RESUMEN

BACKGROUND: Transcription of nodulation genes in rhizobial species is orchestrated by the regulatory nodD gene. Rhizobium tropici strain CIAT 899 is an intriguing species in possessing features such as broad host range, high tolerance of abiotic stresses and, especially, by carrying the highest known number of nodD genes--five--and the greatest diversity of Nod factors (lipochitooligosaccharides, LCOs). Here we shed light on the roles of the multiple nodD genes of CIAT 899 by reporting, for the first time, results obtained with nodD3, nodD4 and nodD5 mutants. METHODS: The three nodD mutants were built by insertion of Ω interposon. Nod factors were purified and identified by LC-MS/MS analyses. In addition, nodD1 and nodC relative gene expressions were measured by quantitative RT-PCR in the wt and derivative mutant strains. Phenotypic traits such as exopolysaccharide (EPS), lipopolysaccharide (LPS), swimming and swarming motilities, biofilm formation and indole acetid acid (IAA) production were also perfomed. All these experiments were carried out in presence of both inducers of CIAT 899, apigenin and salt. Finally, nodulation assays were evaluated in up to six different legumes, including common bean (Phaseolus vulgaris L.). RESULTS: Phenotypic and symbiotic properties, Nod factors and gene expression of nodD3, nodD4 and nodD5 mutants were compared with those of the wild-type (WT) CIAT 899, both in the presence and in the absence of the nod-gene-inducing molecule apigenin and of saline stress. No differences between the mutants and the WT were observed in exopolysaccharide (EPS) and lipopolysaccharide (LPS) profiles, motility, indole acetic acid (IAA) synthesis or biofilm production, either in the presence, or in the absence of inducers. Nodulation studies demonstrated the most complex regulatory system described so far, requiring from one (Leucaena leucocephala, Lotus burtii) to four (Lotus japonicus) nodD genes. Up to 38 different structures of Nod factors were detected, being higher under salt stress, except for the nodD5 mutant; in addition, a high number of structures was synthesized by the nodD4 mutant in the absence of any inducer. Probable activator (nodD3 and nodD5) or repressor roles (nodD4), possibly via nodD1 and/or nodD2, were attributed to the three nodD genes. Expression of nodC, nodD1 and each nodD studied by RT-qPCR confirmed that nodD3 is an activator of nodD1, both in the presence of apigenin and salt stress. In contrast, nodD4 might be an inducer with apigenin and a repressor under saline stress, whereas nodD5 was an inducer under both conditions. CONCLUSIONS: We report for R. tropici CIAT 899 the most complex model of regulation of nodulation genes described so far. Five nodD genes performed different roles depending on the host plant and the inducing environment. Nodulation required from one to four nodD genes, depending on the host legume. nodD3 and nodD5 were identified as activators of the nodD1 gene, whereas, for the first time, it was shown that a regulatory nodD gene-nodD4-might act as repressor or inducer, depending on the inducing environment, giving support to the hypothesis that nodD roles go beyond nodulation, in terms of responses to abiotic stresses.


Asunto(s)
Proteínas Bacterianas/genética , Proteínas Bacterianas/metabolismo , Regulación Bacteriana de la Expresión Génica , Rhizobium tropici/genética , Rhizobium tropici/metabolismo
17.
BMC Genomics ; 16: 251, 2015 Mar 28.
Artículo en Inglés | MEDLINE | ID: mdl-25880529

RESUMEN

BACKGROUND: Nodulation and symbiotic nitrogen fixation are mediated by several genes, both of the host legume and of the bacterium. The rhizobial regulatory nodD gene plays a critical role, orchestrating the transcription of the other nodulation genes. Rhizobium tropici strain CIAT 899 is an effective symbiont of several legumes-with an emphasis on common bean (Phaseolus vulgaris)-and is unusual in carrying multiple copies of nodD, the roles of which remain to be elucidated. RESULTS: Phenotypes, Nod factors and gene expression of nodD1 and nodD2 mutants of CIAT 899 were compared with those of the wild type strain, both in the presence and in the absence of the nod-gene-inducing molecules apigenin and salt (NaCl). Differences between the wild type and mutants were observed in swimming motility and IAA (indole acetic acid) synthesis. In the presence of both apigenin and salt, large numbers of Nod factors were detected in CIAT 899, with fewer detected in the mutants. nodC expression was lower in both mutants; differences in nodD1 and nodD2 expression were observed between the wild type and the mutants, with variation according to the inducing molecule, and with a major role of apigenin with nodD1 and of salt with nodD2. In the nodD1 mutant, nodulation was markedly reduced in common bean and abolished in leucaena (Leucaena leucocephala) and siratro (Macroptilium atropurpureum), whereas a mutation in nodD2 reduced nodulation in common bean, but not in the other two legumes. CONCLUSION: Our proposed model considers that full nodulation of common bean by R. tropici requires both nodD1 and nodD2, whereas, in other legume species that might represent the original host, nodD1 plays the major role. In general, nodD2 is an activator of nod-gene transcription, but, in specific conditions, it can slightly repress nodD1. nodD1 and nodD2 play other roles beyond nodulation, such as swimming motility and IAA synthesis.


Asunto(s)
Proteínas Bacterianas/genética , Fabaceae/microbiología , Genes Bacterianos , Rhizobium tropici/genética , Apigenina/farmacología , Proteínas Bacterianas/metabolismo , Fabaceae/crecimiento & desarrollo , Regulación Bacteriana de la Expresión Génica/efectos de los fármacos , Ácidos Indolacéticos/metabolismo , Mutación , Fijación del Nitrógeno/efectos de los fármacos , Fenotipo , Nodulación de la Raíz de la Planta/efectos de los fármacos , Raíces de Plantas/microbiología , Rhizobium tropici/fisiología , Cloruro de Sodio/farmacología , Simbiosis/genética
18.
J Phys Chem A ; 119(51): 12823-38, 2015 Dec 24.
Artículo en Inglés | MEDLINE | ID: mdl-26618402

RESUMEN

A novel model for the analysis of the rovibrational structure of a molecule based on anharmonic ladder operators associated with the vibrational degrees of freedom is presented. This is devised as an alternative method for the global spectral analysis of rovibrational data considering vibrational anharmonicities from the outset. The present method is thought up with an effective rovibrational Hamiltonian written in terms of angular momentum components and anharmonic Morse ladder operators, associated with rotational and vibrational degrees of freedom, respectively. The resulting Hamiltonian is diagonalized in a symmetry-adapted basis set expressed as a product of rotational states and individual 1D-Morse wave functions for each local vibrational degree of freedom. This approach has been successfully applied to the study of the vibrational structure (up to polyad 14) and the rovibrational structure (up to polyad 2 and J(max) = 20) of hydrogen sulfide. It was shown that this new global analysis formalism is able to reduce considerably the number of fitted parameters with respect to the spectral analysis carried out for separate polyads.

19.
Sensors (Basel) ; 15(10): 26769-82, 2015 Oct 22.
Artículo en Inglés | MEDLINE | ID: mdl-26506353

RESUMEN

This work presents the design, fabrication, and characterization of a printed radio frequency identification tag in the ultra-high frequency band with multiple sensing capabilities. This passive tag is directly screen printed on a cardboard box with the aim of monitoring the packaging conditions during the different stages of the supply chain. This tag includes a commercial force sensor and a printed opening detector. Hence, the force applied to the package can be measured as well as the opening of the box can be detected. The architecture presented is a passive single-chip RFID tag. An electronic switch has been implemented to be able to measure both sensor magnitudes in the same access without including a microcontroller or battery. Moreover, the chip used here integrates a temperature sensor and, therefore, this tag provides three different parameters in every reading.

20.
J Mol Graph Model ; 132: 108819, 2024 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-39029284

RESUMEN

The reactivity and mechanistic intricacies of azatrienes in Diels-Alder reactions have been relatively unexplored despite their intriguing potential applications. In this study, we employ Molecular Electron Density Theory to theoretically investigate the hetero-Diels-Alder reaction involving azatrienes with ethyl vinyl ether and allenyl methyl ether. Analysis of Conceptual Density Functional Theory, energetic profiles, and the topological characteristics is conducted to elucidate the reactions. The revealed mechanism manifests as a polar one-step two-stages process under kinetic control. We establish a clear relationship of between the periselectivity, regioselectivity, and stereoselectivity on one hand and the characteristics of the reactions mechanism on the other hand. The influence of weak interactions on reaction activation barriers and bonding evolution are discussed in detail. We demonstrate that substituents enhancing the reverse electron density flux facilitate the feasibility of the reactions. The results lay ground for a meticulous control of the reaction of azatriene in similar synthetic scenarios.


Asunto(s)
Reacción de Cicloadición , Electrones , Modelos Moleculares , Compuestos Aza/química , Estructura Molecular , Cinética , Termodinámica , Teoría Funcional de la Densidad , Estereoisomerismo
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA