Biochemical, immunological and toxicological characteristics of the crystal proteins of Bacillus thuringiensis subsp. medellin

Characterization of the insecticidal and hemolytic activity of solubilized crystal proteins of Bacillus thuringiensis (Bt) subsp. medellin (Btmed) was performed and compared to solubilized crystal proteins of isolates 1884 of B. thuringiensis subsp. israelensis (Bti) and isolate PG-14 of B. thuringiensis subsp. morrisoni (Btm). In general, at acid pH values solubilization of the Bt crystalline parasporal inclusions (CPI) was lower than at alkaline pH. The larvicidal activity demonstrated by the CPI of Btmed indicated that optimal solubilization of CPI takes place at a pH value of 11.3, in Bti at pH values from 5.03 to 11.3 and in Btm at pH values from 9.05 to 11.3. Hemolytic activity against sheep red blood cells was mainly found following extraction at pH 11.3 in all Bt strains tested. Polyacrylamide gel electrophoresis under denaturing conditions revealed that optimal solubilization of the CPI in all Bt strains takes place at the alkaline pH values from 9.05 to 11.3. An enriched preparation of Btmed crystals was obtained, solubilized and crystal proteins were separated on a size exclusion column (Sephacryl S-200). Three main protein peaks were observed on the chromatogram. The first peak had two main proteins that migrate between 90 to 100 kDa. These proteins are apparently not common to other Bt strains isolated to date. The second and third peaks obtained from the size exclusion column yielded polypeptides of 68 and 28-30 kDa, respectively. Each peak independently, showed toxicity against 1st instar Culex quinquefasciatus larvae. Interestingly, combinations of the fractions corresponding to the 68 and 30 kDa protein showed an increased toxicity. These results suggest that the 94 kDa protein is an important component of the Btmed toxins with the highest potency to kill mosquito larvae. When crystal proteins of Bti were probed with antisera raised independently against the three main protein fractions of Btmed, the only crystal protein that showed cross reaction was the 28 kDa protein. These data suggest that Btmed could be an alternative bacterium for mosquito control programs in case mosquito larval resistance emerges to Bti toxic proteins.

Sistema didàctic per millorar l'aprenetatge de la representació del espai arquitectònic amb ajuts "on line"

El projecte ha tingut com a finalitat cobrir un buit en la formació dels estudiants pel que respecta a les seves limitacions en l’aprenentatge de les diferents estratègies i metodologies de treball. Aquest buit ens ha fet pensar en l’elaboració d’un sistema didàctic que possibiliti una comunicació fluida amb l’alumne i que pugui anar més enllà de l’àmbit específic de les aules. Es per això que la nostra proposta té com a referent un aprofitament més racional del temps de treball de l’estudiant. Per tal d’arribar a aquesta finalitat ens hem plantejat un grup d’objectius concrets ordenats segons els dos nivells d’assoliment següents: Nivell 1: - Definir un material didàctic que pugui transmetre de la manera més objectiva possible les eines necessàries per tal que l’alumne resolgui un conjunt de problemes concrets. - Proporcionar a l’estudiant un procediment didàctic basat en un grup de tasques amb un material de suport on ha de posar a prova l’aplicabilitat dels conceptes donats a les classes teòriques. - Partir d’un sistema que permeti a l’alumne tenir una referència constant de recolzament teòric fora de les aules quan està resolent les pràctiques assignades en el curs. - Definir unes característiques funcionals del material utilitzat en l’activitat pràctica de tal manera que sigui un instrument efectiu per al control del propi estudiant sobre el seu procés d’avaluació. Nivell 2: - Fer servir una metodologia d’activitats pràctiques on es puguin accentuar les capacitats de resposta creativa individual de l’estudiant. - Plantejar l’intercanvi d’experiències i propostes d’estratègies per a la resolució dels temes pràctics mitjançant sessions de seminaris prèvies a les pràctiques. - Promoure unes relacions transversals amb altres àrees de coneixement de tal manera que l’alumne pugui vincular la seva resposta a les activitats pràctiques proposades per altres assignatures, amb els coneixements adquirits a la nostra assignatura.

Tuberculosis in HIV-negative and HIV-infected patients in a low-incidence country: clinical characteristics and treatment outcomes.

BACKGROUND: In Switzerland and other developed countries, the number of tuberculosis (TB) cases has been decreasing for decades, but HIV-infected patients and migrants remain risk groups. The aim of this study was to compare characteristics of TB in HIV-negative and HIV-infected patients diagnosed in Switzerland, and between coinfected patients enrolled and not enrolled in the national Swiss HIV Cohort Study (SHCS). METHODS AND FINDINGS: All patients diagnosed with culture-confirmed TB in the SHCS and a random sample of culture-confirmed cases reported to the national TB registry 2000-2008 were included. Outcomes were assessed in HIV-infected patients and considered successful in case of cure or treatment completion. Ninety-three SHCS patients and 288 patients selected randomly from 4221 registered patients were analyzed. The registry sample included 10 (3.5%) coinfected patients not enrolled in the SHCS: the estimated number of HIV-infected patients not enrolled in the SHCS but reported to the registry 2000-2008 was 146 (95% CI 122-173). Coinfected patients were more likely to be from sub-Saharan Africa (51.5% versus 15.8%, P<0.0001) and to present disseminated disease (23.9% vs. 3.4%, P<0.0001) than HIV-negative patients. Coinfected patients not enrolled in the SHCS were asylum seekers or migrant workers, with lower CD4 cell counts at TB diagnosis (median CD4 count 79 cells/µL compared to 149 cells/µL among SHCS patients, P = 0.07). There were 6 patients (60.0%) with successful outcomes compared to 82 (88.2%) patients in the SHCS (P = 0.023). CONCLUSIONS: The clinical presentation of coinfected patients differed from HIV-negative TB patients. The number of HIV-infected patients diagnosed with TB outside the SHCS is similar to the number diagnosed within the cohort but outcomes are poorer in patients not followed up in the national cohort. Special efforts are required to address the needs of this vulnerable population.

Coordinació docent concreta i grups pilot EEES com a instruments per la millora de la qualitat docent i com a estratègia per la migració a l'EEES a Facultat de Dret

El projecte s'ha dut a terme a la Facultat de Dret de la Universitat de Barcelona durant el curs 2006-2007 (setembre a juliol). La finalitat principal del projecte ha estat impulsar la coordinació entre docents d'un mateix grup i iniciar la transició cap a l'Espai Europeu d’Ensenyament Superior. En aquest context, les accions desenvolupades han estat la creació de 6 grups pilot (tres a primer, dos a segon i un a tercer) adaptats a l'EEES i la formació d'equips docents dels professors implicats en aquests grups. Des de la Facultat de Dret, es van determinar les característiques i els criteris metodològics que definirien aquests grups i que els docents implicats havien de seguir. Per altra banda, els professors que formaven part d’un mateix grup es constituïen com a equip docent amb la funció de coordinar-se pel bon desenvolupament del grup. Cada equip docent comptava amb la figura del coordinador que era un docent del grup escollit pel conjunt de professors i que tenia com a funcions la de convocar les reunions, redactar les actes amb els acords establerts i fer d’enllaç entre els alumnes i els docents d’un mateix grup. El desenvolupament del projecte s’ha efectuat en tres fases: planificació i definició dels grups pilot i equips docents, l’execució del curs en els criteris metodològics establerts i la de valoració de l’experiència.

Change in individual growth rate and its link to gill-net fishing in two sympatric whitefish species

Size-selective fishing is expected to affect traits such as individual growth rate, but the relationship between the fishery-linked selection differentials and the corresponding phenotypic changes is not well understood. We analysed a 25-year monitoring survey of sympatric populations of the two Alpine whitefish Coregonus albellus and C. fatioi. We determined the fishing-induced selection differentials on growth rates, the actual change of growth rates over time, and potential indicators of reproductive strategies that may change over time. We found marked declines in adult growth rate and significant selection differentials that may partly explain the observed declines. However, when comparing the two sympatric species, the selection differentials on adult growth were stronger in C. albellus while the decline in adult growth rate seemed more pronounced in C. fatioi. Moreover, the selection differential on juvenile growth was significant in C. albellus but not in C. fatioi, while a significant reduction in juvenile growth over the last 25 years was only found in C. fatioi. Our results suggest that size-selective fishing affects the genetics for individual growth in these whitefish, and that the link between selection differentials and phenotypic changes is influenced by species-specific factors.

Euler characteristics of categories and homotopy colimits

"Vegeu el resum a l'inici del document del fitxer adjunt."

Relating the permeability of quartz sands to their grain size and spectral induced polarization characteristics

Recently, Revil & Florsch proposed a novel mechanistic model based on the polarization of the Stern layer relating the permeability of granular media to their spectral induced polarization (SIP) characteristics based on the formation of polarized cells around individual grains. To explore the practical validity of this model, we compare it to pertinent laboratory measurements on samples of quartz sands with a wide range of granulometric characteristics. In particular, we measure the hydraulic and SIP characteristics of all samples both in their loose, non-compacted and compacted states, which might allow for the detection of polarization processes that are independent of the grain size. We first verify the underlying grain size/permeability relationship upon which the model of Revil & Florsch is based and then proceed to compare the observed and predicted permeability values for our samples by substituting the grain size characteristics by corresponding SIP parameters, notably the so-called Cole-Cole time constant. In doing so, we also asses the quantitative impact of an observed shift in the Cole-Cole time constant related to textural variations in the samples and observe that changes related to the compaction of the samples are not relevant for the corresponding permeability predictions. We find that the proposed model does indeed provide an adequate prediction of the overall trend of the observed permeability values, but underestimates their actual values by approximately one order-of-magnitude. This discrepancy in turn points to the potential importance of phenomena, which are currently not accounted for in the model and which tend to reduce the characteristic size of the prevailing polarization cells compared to the considered model, such as, for example, membrane polarization, contacts of double-layers of neighbouring grains, and incorrect estimation of the size of the polarized cells because of the irregularity of natural sand grains.

Epidemiological Characteristics of Schistosoma mansoni Infection in Rural and Urban Endemic Areas of Minas Gerais, Brazil

To compare the epidemiological profile and socioeconomic factors associated to the infection by Schistosoma mansoni in a rural and an urban endemic area a cross-sectional study was performed in Água Branca de Minas (rural area) and Bela Fama (urban area), both situated in the State of Minas Gerais, Brazil. Two hundred and eighty eight individuals were surveyed in the rural area and 787 in the urban area. Water contact and socioeconomic questionnaires were used to identify risk factors for the infection. The prevalences of 38.8% and 9.7% and the geometric mean of eggs per gram of faeces of 117.8 and 62.3 were found in the rural and urban areas, respectively. By multivariate statistical analysis age groups over nine years old and previous specific treatment were associated with the infection in rural area. In urban area age over nine years old, low quality housing, weekly fishing and swimming were associated after adjustment by logistic regression

Age effects, unobserved characteristics and hedonic price indexes: The Spanish car market in the 1990s

This paper computes and compares alternative quality-adjusted price indexes for new cars in Spain in the period 1990-2000. The proposed hedonic approach simultaneously controls for time-invariant unobserved product e¤ects and time-variant unobserved quality changes, that are assumed to be captured by model age effects. The results show that the non-adjusted price index largely overstates the increase in the cost of living induced by changes in car prices and that previous evidence for this market have not measured the real extent of that bias, probably due to the omission of controls for unobservables. It is also shown that omitting age effects can also lead to misleading conclusions. The estimated price indexes give also some insights on what could have been the determinants of price evolution in the Spanish car market.

The lack of effect of insulin on luteinizing hormone pulsatility in healthy male volunteers provides evidence of a sexual dimorphism in the metabolic regulation of reproductive hormones.

BACKGROUND: The activity of the neuroendocrine reproductive axis is closely related to nutritional status. This link is particularly important in healthy women, in whom insulin is a positive signal for the reproductive system. In contrast, very little is known regarding this relation in men. OBJECTIVES: This study was designed to evaluate the effect of insulin on the reproductive axis of young male volunteers and to study the effect of short-term hypercaloric feeding on this modulation. DESIGN: The activity of the neuroendocrine reproductive axis was characterized by the pattern of endogenous luteinizing hormone (LH) secretion on the basis of frequent blood sampling protocols. The effect of insulin was tested by comparing the LH secretion pattern between a baseline study and a hyperinsulinemic euglycemic clamp. These studies were performed first in subjects fed a controlled isocaloric diet for 6 d (calculated as 1.5 times their resting metabolic rate) then in the same subjects fed a controlled hypercaloric diet in which 30% extra calories were provided as fat and fructose (3 g · kg(-1) · d(-1)) before undergoing identical protocols. Serum gonadotropins, sex steroids, glucose, insulin, ghrelin, and leptin concentrations were assessed, and the HOMA-IR was calculated. RESULTS: The LH secretion pattern was not affected by insulin or by hypercaloric feeding. Insulin decreased ghrelin and increased leptin concentrations but had no additional effect of hypercaloric feeding despite significantly lower HOMA-IR indexes. CONCLUSIONS: Our data indicate that neither insulin nor short-term hypercaloric feeding has any effect on the activity of the male reproductive axis. They also further support the association between ghrelin and insulin and glucose metabolism. This trial was registered at clinicaltrials.gov as NCT01058681.

Age effects, unobserved characteristics and hedonic price indexes: The Spanish car market in the 1990's

This paper computes and compares alternative quality-adjusted price indexes for new cars in Spain in the period 1990-2000. The proposed hedonic approach simultaneously controls for time-invariant unobserved product effects and time-variant unobserved quality changes, that are assumed to be captured by model age effects. The results show that the non-adjusted price index largely overstates the increase in the cost of living induced by changes in car prices and that previous evidence for this market have not measured the real extent of that bias, probably due to the omission of controls for unobservables. It is also shown that omitting age effects can also lead to misleading conclusions. The estimated price indexes give also some insights on what could have been the determinants of price evolution in the Spanish car market. JEL classi…fication numbers: C43, E31, L11, L13, Keywords: Hedonic price indexes, Spanish car market, car prices, CPI, Cost of living

The intensity of human body odors and the MHC: should we expect a link?

It is now well established that genes within the major histocompatibility complex (MHC) somehow affect the production of body odors in several vertebrates, including humans. Here we discuss whether variation in the intensity of body odors may be influenced by the MHC. In order to examine this question, we have to control for MHC-linked odor perception on the smeller's side. Such a control is necessary because the perception of pleasantness and intensity seem to be confounded, and the causalities are still unsolved. It has previously been found that intense odors are scored as less pleasant if the signaler and the receiver are of MHC-dissimilar type, but not if they are of MHC similar type. We argue, and first data suggest, that an effect of the degree of MHC-heterozygosity and odor intensity is likely (MHC-homozygotes may normally smell more intense), while there is currently no strong argument for other possible links between the MHC and body odor intensity.

Evolution of decision-making and learning under fluctuating social environments

The capacity to learn to associate sensory perceptions with appropriate motor actions underlies the success of many animal species, from insects to humans. The evolutionary significance of learning has long been a subject of interest for evolutionary biologists who emphasize the bene¬fit yielded by learning under changing environmental conditions, where it is required to flexibly switch from one behavior to another. However, two unsolved questions are particularly impor¬tant for improving our knowledge of the evolutionary advantages provided by learning, and are addressed in the present work. First, because it is possible to learn the wrong behavior when a task is too complex, the learning rules and their underlying psychological characteristics that generate truly adaptive behavior must be identified with greater precision, and must be linked to the specific ecological problems faced by each species. A framework for predicting behavior from the definition of a learning rule is developed here. Learning rules capture cognitive features such as the tendency to explore, or the ability to infer rewards associated to unchosen actions. It is shown that these features interact in a non-intuitive way to generate adaptive behavior in social interactions where individuals affect each other's fitness. Such behavioral predictions are used in an evolutionary model to demonstrate that, surprisingly, simple trial-and-error learn¬ing is not always outcompeted by more computationally demanding inference-based learning, when population members interact in pairwise social interactions. A second question in the evolution of learning is its link with and relative advantage compared to other simpler forms of phenotypic plasticity. After providing a conceptual clarification on the distinction between genetically determined vs. learned responses to environmental stimuli, a new factor in the evo¬lution of learning is proposed: environmental complexity. A simple mathematical model shows that a measure of environmental complexity, the number of possible stimuli in one's environ¬ment, is critical for the evolution of learning. In conclusion, this work opens roads for modeling interactions between evolving species and their environment in order to predict how natural se¬lection shapes animals' cognitive abilities. - La capacité d'apprendre à associer des sensations perceptives à des actions motrices appropriées est sous-jacente au succès évolutif de nombreuses espèces, depuis les insectes jusqu'aux êtres hu¬mains. L'importance évolutive de l'apprentissage est depuis longtemps un sujet d'intérêt pour les biologistes de l'évolution, et ces derniers mettent l'accent sur le bénéfice de l'apprentissage lorsque les conditions environnementales sont changeantes, car dans ce cas il est nécessaire de passer de manière flexible d'un comportement à l'autre. Cependant, deux questions non résolues sont importantes afin d'améliorer notre savoir quant aux avantages évolutifs procurés par l'apprentissage. Premièrement, puisqu'il est possible d'apprendre un comportement incorrect quand une tâche est trop complexe, les règles d'apprentissage qui permettent d'atteindre un com¬portement réellement adaptatif doivent être identifiées avec une plus grande précision, et doivent être mises en relation avec les problèmes écologiques spécifiques rencontrés par chaque espèce. Un cadre théorique ayant pour but de prédire le comportement à partir de la définition d'une règle d'apprentissage est développé ici. Il est démontré que les caractéristiques cognitives, telles que la tendance à explorer ou la capacité d'inférer les récompenses liées à des actions non ex¬périmentées, interagissent de manière non-intuitive dans les interactions sociales pour produire des comportements adaptatifs. Ces prédictions comportementales sont utilisées dans un modèle évolutif afin de démontrer que, de manière surprenante, l'apprentissage simple par essai-et-erreur n'est pas toujours battu par l'apprentissage basé sur l'inférence qui est pourtant plus exigeant en puissance de calcul, lorsque les membres d'une population interagissent socialement par pair. Une deuxième question quant à l'évolution de l'apprentissage concerne son lien et son avantage relatif vis-à-vis d'autres formes plus simples de plasticité phénotypique. Après avoir clarifié la distinction entre réponses aux stimuli génétiquement déterminées ou apprises, un nouveau fac¬teur favorisant l'évolution de l'apprentissage est proposé : la complexité environnementale. Un modèle mathématique permet de montrer qu'une mesure de la complexité environnementale - le nombre de stimuli rencontrés dans l'environnement - a un rôle fondamental pour l'évolution de l'apprentissage. En conclusion, ce travail ouvre de nombreuses perspectives quant à la mo¬délisation des interactions entre les espèces en évolution et leur environnement, dans le but de comprendre comment la sélection naturelle façonne les capacités cognitives des animaux.

Placebo effect characteristics observed in a single, international, longitudinal study in Huntington's disease.

BACKGROUND: Classically, clinical trials are based on the placebo-control design. Our aim was to analyze the placebo effect in Huntington's disease. METHODS: Placebo data were obtained from an international, longitudinal, placebo-controlled trial for Huntington's disease (European Huntington's Disease Initiative Study Group). One-hundred and eighty patients were evaluated using the Unified Huntington Disease Rating Scale over 36 months. A placebo effect was defined as an improvement of at least 50% over baseline scores in the Unified Huntington Disease Rating Scale, and clinically relevant when at least 10% of the population met it. RESULTS: Only behavior showed a significant placebo effect, and the proportion of the patients with placebo effect ranged from 16% (first visit) to 41% (last visit). Nondepressed patients with better functional status were most likely to be placebo-responders over time. CONCLUSIONS: In Huntington's disease, behavior seems to be more vulnerable to placebo than overall motor function, cognition, and function