A mesoscopic stochastic model for the specific consumption rate in substrate-limited microbial growth

The specific consumption rate of substrate, as well as the associated specific growth rate, is an essential parameter in the mathematical description of substrate-limited microbial growth. In this paper we develop a completely new kinetic model of substrate transport, based on recent knowledge on the structural biology of transport proteins, which correctly describes very accurate experimental results at near-zero substrate concentration values found in the literature, where the widespread Michaelis-Menten model fails. Additionally, our model converges asymptotically to Michaelis-Menten predictions as substrate concentration increases. Instead of the single active site enzymatic reaction of Michaelis-Menten type, the proposed model assumes a multi-site kinetics, simplified as an apparent all-or-none mechanism for the transport, which is controlled by means of the local substrate concentration in the close vicinity of the transport protein. Besides, the model also assumes that this local concentration is not equal to the mean substrate concentration experimentally determined in the culture medium. Instead, we propose that it fluctuates with a mostly exponential distribution of Weibull type

Ensayo sobre la vegetación rupícola basófila de la clase Aslenietea trichornanis en la provincia corológica bética

Se hace un estudio y recopilación de las comunidades vegetales rupícolas basófilas de la provincia corológica Bética. En este contexto, se proponen algunas combinaciones y sinonimias y se describe la alianza Campano/ion relutinae y las asociaciones Teucrio- Linarietum lilacinue, Saxifragetum camposii y Anthyllido-Arenarietum alfacarensis.The rupicolous calcicoles communities of the Betica biogeographical province have been studied and compiled. Some combinations and synonymy are proposed and the alliance Campanulion velutinae and the associations Teucrio-Linarietum lilacinue, Saxifragetum composh and Anthyllido-Arenarietum ahracarensis are also described

Validation of a new equation to calculate the maximum oxygen uptake

The main regression equations to estimate the maximum oxygen uptake (V02maxl have been obtained with the total population studied [1-31. A limitation of these studies is the validity, since the prediction equations were carried out with a particular population and they were validated with themselves, because the samples did not tend to be very large. The cross validation must be used to check the accuracy of a prediction equations when they are applied to different populations. The aim of this study was to determine the validity of the maximum oxygen uptake prediction equation obtained with cross validation

Can the exercise mode determine lipid profile improvements in obese patients?

Influencia del modo de ejercicio sobre el perfil lipídic

Strain typing of Zygosaccharomyces yeast species using a single molecular method based on polymorphism of the intergenic spacer region (IGS)

Unlike previously reported methods that need a combination of several typing techniques, we have 22 developed a single method for strain typing of the Zygosaccharomyces bailii, Z. mellis and Z. rouxii spoilage 23 species. Strains belonging to other species have also been included for comparison. We have demonstrated 24 that the IGS-PCR RFLP method has a high discriminative power. Considering the three endonucleases used in 25 this work, we have obtained a variability of 100% for Z. mellis and Z. rouxii strains and up to 70% for Z.bailii. 26 We have also detected two misidentified Z. mellis strains (CBS 711 and CBS 7412) which have RFLP patterns 27 with a set of bands characteristic of Z. rouxii strains. Sequencing of 26S rDNA D1/D2 domains and the 5.8-ITS 28 rDNA region confirmed these strains as Z. rouxii. The method also groups three certified hybrid strains of 29 Zygosaccharomyces in a separate cluster

Dificultades en el aprendizaje de la Biología Celular según la opinión del alumnado

Relacionar la implicación de los constituyentes celulares con la función celular y la comprensión del organismo como resultado del funcionamiento coordinado de todas sus células, es uno de los objetivos más importantes que determinarán la actuación docente y la calidad del aprendizaje en la asignatura de Biología Celular. Sin embargo, son muchos los obstáculos asociados a este proceso, entre otros, la naturaleza abstracta de los conceptos, la terminología utilizada para explicarlos, la interpretación de imágenes, la representación mental del concepto célula así como de los procesos bioquímicos que en ella tienen lugar. Reflexionar sobre las dificultades, tanto del profesorado como del alumnado, sin duda servirá para orientar el curriculum en el desarrollo de competencias, mejorar la percepción de la utilidad de los contenidos por parte del estudiante, así como la capacidad de transferirlos y aplicarlos a diferentes contextos y situaciones relevantes. Para ello, en el presente trabajo recogemos, desde la opinión de los estudiantes, las dificultades a las que se enfrenta el alumnado de la asignatura de Biología Celular en el primer curso del Grado en Ciencias del Mar, así como los conceptos que les resultan más difíciles de aprender

Metabolic risk score indexes validation in overweight healthy people

The constellation of adverse cardiovascular disease (CVD) and metabolic risk factors, including elevated abdominal obesity, blood pressure (BP), glucose, and triglycerides (TG) and lowered high-density lipoprotein-cholesterol (HDL-C), has been termed the metabolic syndrome (MetSyn) [1]. A number of different definitions have been developed by the World Health Organization (WHO) [2], the National Cholesterol Education Program Adult Treatment Panel III (ATP III) [3], the European Group for the Study of Insulin Resistance (EGIR) [4] and, most recently, the International Diabetes Federation (IDF) [5]. Since there is no universal definition of the Metabolic Syndrome, several authors have derived different risk scores to represent the clustering of its components [6-11]