Innovation in biology: from Louis Pasteur to internet social networks

Throughout his scientific career, Louis Pasteur developed numerous applications for his research, thus providing many examples of the innovation process. The context of his innovations remained relatively stable until the '60s and '70s, but major changes have occurred since then, involving aspects such as regulations, ethics, social acceptance, precautionary principle, etc. The emergence of social networks on the Internet also led to new practices, such as cloud computing and collective intelligencePar les nombreuses applications de sa recherche qu’il a développées tout au long de sa carrière scientifique, Louis Pasteur a illustré de nombreux aspects du processus d’innovation. Le cadre dans lequel il a ainsi innové est resté relativement stable jusqu’aux années 1960-70, mais l’environnement de l’innovation a connu depuis de nombreux bouleversements : réglementation, éthique, acceptation sociétale, principe de précaution, etc. L’apparition des réseaux sociaux sur internet a aussi fait évoluer les pratiques, notamment via l’émergence de l’intelligence collectiv

Dynamiques territoriales et gestion de la Fièvre Porcine Africaine : rétrospective bibliographique et étude de terrain dans le Sud-Ouest français

La Fièvre Porcine africaine est une maladie virale mortelle affectant les suidés et qui tend à se propager rapidement en Europe et dans le monde depuis le début du siècle. Les pays encore indemnes se doivent de mettre en place des mesures de prévention strictes car l'introduction du virus a de graves conséquences économiques pour les pays. Une surveillance accrue de la faune sauvage, des mesures de biosécurité en élevages ainsi que des campagnes de sensibilisation ont été initiées en France, pays voisin de la Belgique, récemment contaminée et de la Sardaigne où la maladie est endémique. De nombreuses mesures très coûteuses sont imposées aux éleveurs. Les vétérinaires ont un rôle de conseil dans leur mise en place. Les chasseurs sont impliqués dans la surveillance de la faune sauvage. Les institutions mettent à disposition un grand nombre de supports de communication afin de sensibiliser sur la maladie et sur les gestes à adopter

A Technique for Characterizing the Development of Rhythms in Bird Song

The developmental trajectory of nervous system dynamics shows hierarchical structure on time scales spanning ten orders of magnitude from milliseconds to years. Analyzing and characterizing this structure poses significant signal processing challenges. In the context of birdsong development, we have previously proposed that an effective way to do this is to use the dynamic spectrum or spectrogram, a classical signal processing tool, computed at multiple time scales in a nested fashion. Temporal structure on the millisecond timescale is normally captured using a short time Fourier analysis, and structure on the second timescale using song spectrograms. Here we use the dynamic spectrum on time series of song features to study the development of rhythm in juvenile zebra finch. The method is able to detect rhythmic structure in juvenile song in contrast to previous characterizations of such song as unstructured. We show that the method can be used to examine song development, the accuracy with which rhythm is imitated, and the variability of rhythms across different renditions of a song. We hope that this technique will provide a standard, automated method for measuring and characterizing song rhythm

Glutathione reductase-catalyzed cascade of redox reactions to bioactivate potent antimalarial 1,4-naphthoquinones--a new strategy to combat malarial parasites.

Our work on targeting redox equilibria of malarial parasites propagating in red blood cells has led to the selection of six 1,4-naphthoquinones, which are active at nanomolar concentrations against the human pathogen Plasmodium falciparum in culture and against Plasmodium berghei in infected mice. With respect to safety, the compounds do not trigger hemolysis or other signs of toxicity in mice. Concerning the antimalarial mode of action, we propose that the lead benzyl naphthoquinones are initially oxidized at the benzylic chain to benzoyl naphthoquinones in a heme-catalyzed reaction within the digestive acidic vesicles of the parasite. The major putative benzoyl metabolites were then found to function as redox cyclers: (i) in their oxidized form, the benzoyl metabolites are reduced by NADPH in glutathione reductase-catalyzed reactions within the cytosols of infected red blood cells; (ii) in their reduced forms, these benzoyl metabolites can convert methemoglobin, the major nutrient of the parasite, to indigestible hemoglobin. Studies on a fluorinated suicide-substrate indicate as well that the glutathione reductase-catalyzed bioactivation of naphthoquinones is essential for the observed antimalarial activity. In conclusion, the antimalarial naphthoquinones are suggested to perturb the major redox equilibria of the targeted infected red blood cells, which might be removed by macrophages. This results in development arrest and death of the malaria parasite at the trophozoite stage

Synthesis of New 4-Aminoquinolines and Evaluation of Their In Vitro Activity against Chloroquine-Sensitive and Chloroquine-Resistant Plasmodium falciparum

International audienceThe efficacy of chloroquine, once the drug of choice in the fight against Plasmodium falcipa-rum, is now severely limited due to widespread resistance. Amodiaquine is one of the most potent antimalarial 4-aminoquinolines known and remains effective against chloroquine-resistant parasites, but toxicity issues linked to a quinone-imine metabolite limit its clinical use. In search of new compounds able to retain the antimalarial activity of amodiaquine while circumventing quinone-imine metabolite toxicity, we have synthesized five 4-amino-quinolines that feature rings lacking hydroxyl groups in the side chain of the molecules and are thus incapable of generating toxic quinone-imines. The new compounds displayed high in vitro potency (low nanomolar IC 50), markedly superior to chloroquine and comparable to amodiaquine, against chloroquine-sensitive and chloroquine-resistant strains of P. falcipa-rum, accompanied by low toxicity to L6 rat fibroblasts and MRC5 human lung cells, and metabolic stability comparable or higher than that of amodiaquine. Computational studies indicate a unique mode of binding of compound 4 to heme through the HOMO located on a biphenyl moeity, which may partly explain the high antiplasmodial activity observed for this compound

Antimicrobial Agents for Textiles: Types, Mechanisms and Analysis Standards

The large surface area, and ability to retain moisture of textile structures enable microorganisms’ growth, which causes a range of undesirable effects, not only on the textile itself, but also on the user. Moreover, textiles used in health care environments are required to possess antimicrobial property to minimize spread of pathogenic infection. Anti-microbial property can be imparted via chemical finishing with an antimicrobial agent. Currently the use of antimicrobial agents includes metal compounds (notably copper and silver particle), chitosan, halogenated phenols “triclosan”, quaternary ammonium compounds, antibiotics (a class of antimicrobials produced from microorganisms that act against one another), and N-halamines. The possibility of bacterial resistance limits antibiotic use to specific medical applications, and triclosan is known for being dangerous to the environment and is currently under scrutiny for possible endocrine disrupting to human being. Although quaternary ammonium compounds are stable and easily manufactured, microbial resistance is also a concern. Quaternary ammonium compounds (QACs), Polyhexamethylene Biguanide (PHMB), chitosan and N-halamines are listed under bound or non-leaching type antimicrobials. The bulk of current chapter focuses on the different family of antimicrobial agents used for textiles and their mechanisms

Econophysics of a religious cult: the Antoinists in Belgium [1920-2000]

In the framework of applying econophysics ideas in religious topics, the finances of the Antoinist religious movement organized in Belgium between 1920 and 2000 are studied. The interest of investigating financial aspects of such a, sometimes called, sect stems in finding characteristics of conditions and mechanisms under which definitely growth AND decay features of communities can be understood. The legally reported yearly income and expenses between 1920 and 2000 are studied. A three wave asymmetric regime is observed over a trend among marked fluctuations at time of crises. The data analysis leads to propose a general mechanistic model taking into account an average GDP growth, an oscillatory monetary inflation and a logistic population drift.Comment: 20 pages, 6 figures, 2 tables, 51 references; prepared for Physica A; now including title, author, address and abstrac

The Song Must Go On: Resilience of the Songbird Vocal Motor Pathway

Stereotyped sequences of neural activity underlie learned vocal behavior in songbirds; principle neurons in the cortical motor nucleus HVC fire in stereotyped sequences with millisecond precision across multiple renditions of a song. The geometry of neural connections underlying these sequences is not known in detail though feed-forward chains are commonly assumed in theoretical models of sequential neural activity. In songbirds, a well-defined cortical-thalamic motor circuit exists but little is known the fine-grain structure of connections within each song nucleus. To examine whether the structure of song is critically dependent on long-range connections within HVC, we bilaterally transected the nucleus along the anterior-posterior axis in normal-hearing and deafened birds. The disruption leads to a slowing of song as well as an increase in acoustic variability. These effects are reversed on a time-scale of days even in deafened birds or in birds that are prevented from singing post-transection. The stereotyped song of zebra finches includes acoustic details that span from milliseconds to seconds–one of the most precise learned behaviors in the animal kingdom. This detailed motor pattern is resilient to disruption of connections at the cortical level, and the details of song variability and duration are maintained by offline homeostasis of the song circuit

Variation in Reproductive Success Across Captive Populations: Methodological Differences, Potential Biases and Opportunities

Our understanding of fundamental organismal biology has been disproportionately influenced by studies of a relatively small number of model\u27 species extensively studied in captivity. Laboratory populations of model species are commonly subject to a number of forms of past and current selection that may affect experimental outcomes. Here, we examine these processes and their outcomes in one of the most widely used vertebrate species in the laboratory - the zebra finch (Taeniopygia guttata). This important model species is used for research across a broad range of fields, partly due to the ease with which it can be bred in captivity. However despite this perceived amenability, we demonstrate extensive variation in the success with which different laboratories and studies bred their subjects, and overall only 64% of all females that were given the opportunity, bred successfully in the laboratory. We identify and review several environmental, husbandry, life-history and behavioural factors that potentially contribute to this variation. The variation in reproductive success across individuals could lead to biases in experimental outcomes and drive some of the heterogeneity in research outcomes across studies. The zebra finch remains an excellent captive animal system and our aim is to sharpen the insight that future studies of this species can provide, both to our understanding of this species and also with respect to the reproduction of captive animals more widely. We hope to improve systematic reporting methods and that further investigation of the issues we raise will lead both to advances in our fundamental understanding of avian reproduction as well as to improvements in future welfare and experimental efficiency