Dietary proteins: from evolution to engineering

Because of the indispensable amino acids dietary proteins are the most important macronutrients. Proper growth and body maintenance depends on the quantity and quality of protein intake and proteins have thus been most crucial throughout evolution with hominins living in quite diverse food ecosystems. Developments in agriculture and food science have increased availability and diversity of food including protein for a rapidly growing world population while nutrient deficiencies resulting in stunting in children for example have been reduced. Nevertheless, the developing world and growing population needs more protein of high quality – with around 400 million tons per annum estimated for 2050. In contrary, protein consumption in all developed countries exceeds meanwhile the recommended intakes considerably with consequences for health and the environment. There is a growing interest in dietary proteins driven by the quest for more sustainable diets and the increasing food demand for a growing world population. This brings new and novel sources such as algae, yeast, insects or bacteria into play in delivering the biomass but also new technologies such as precision fermentation or in vitro meat/fish or dairy. What needs to be considered when such new protein sources are explored is that proteins need to provide not only the required amino acids but also functionality in the food produced thereof. This review considers human physiology and metabolism in the context of protein intake from an evolutionary perspective and prospects on future protein production

Le don altruiste et la laïcité comme fondements à la structuration des services sociaux, de santé et d’éducation : l’œuvre du Dr. Wilfred Thomason Grenfell (1865-1940)

L’objectif de cette thèse est d’explorer le don altruiste et sa vertu de déboucher à la structuration laïque des services publics par la méthode phénoménologique. Soit-elle religieuse, spirituelle ou humaniste, la motivation du don altruiste n’empêche pas d’offrir des services essentiels de façon universelle et laïque. En parcourant les événements de l’histoire britannique et en prenant en exemple la vie, les œuvres, et les écrits du Dr Grenfell, nous mettons en évidence le cheminement de ce fil blanc qu’est le don altruiste. Avant de décrire les événements spécifiques lesquels s’emboîtent, à leur insu, de façon cohérente avec nos hypothèses, il s’agit de différencier le don réciproque, lequel engendre la dette soit matérielle, soit d’allégeance et/ou de l’obligation, du don altruiste lequel ne demande pas de la réciprocité. Ceci, en référant à l’évolution de la pensée philosophique et aux avancés en sciences sociales par des anthropologues et par des sociologues. Les piliers de la laïcité étant les principes de la bienveillance, la dignité, l’égalité et la liberté de conscience, nous examinerons aussi leur évolution. Comme étude de cas spécifique, nous choisissons, parmi de nombreuses associations caritatives non confessionnelles, une plus proche de chez nous, en l’occurrence, l’œuvre du Britannique Dr Wilfred Thomason Grenfell, fondateur de l’International Grenfell Association (1914), œuvrant sur le littoral du Labrador, du nord-ouest de Terre-Neuve et de la Basse-Côte-Nord du golfe du Saint-Laurent. Mais avant, il est de mise de mettre le Dr Grenfell dans son contexte en décortiquant l’histoire, souvent houleuse et pénible, de l’évolution de la bienveillance envers la population fragilisée au niveau des jurisprudences et de la philanthropie en Grande-Bretagne. Ceci nous permet d’isoler des événements entourant la bienfaisance cheminant vers la « laïcité ». Issu des principes de la dignité et de la recherche de l’égalité sociale dès l’ère celtique, soumis pendant des siècles aux contraintes religieuses et politiques, le don altruiste prend son essor à la fin du 19e siècle, lors de l’adoption du principe de la liberté de conscience, permettant les œuvres de bienfaisance de desservir de façon universelle toute la population. Dès le tournant du 20e siècle, l’État britannique adopta des lois concluant la « laïcité » dans le domaine des services à la population, sans toutefois nier l’Église d’État qui n’a pas de pouvoir de veto au Parlement. Notre exemple, le Dr Grenfell, dès son arrivée en 1892, octroyait des services essentiels de façon universelle et laïque en respectant la liberté de conscience, en redonnant la dignité et l’égalité des chances à toute une population de pêcheurs et leurs familles délaissées par les centres urbains. Et ceci, sans discrimination religieuse, ethnique et sociale autant chez les bénéficiaires que chez les intervenants; catholiques, anglicans, presbytériens, méthodistes, Moraves, unitariens, non-chrétiens, et non-croyants; Anglais, Irlandais, Français, Naskapi, Innus, Inuits. La motivation spirituelle et humaniste du Dr Grenfell, des donateurs, des bénévoles et des intervenants professionnels de l’« extérieur », par leurs dons altruistes, permit le rayonnement de l’IGA et le développement de services laïcs

Metastability limit for the nucleation of NaCl crystals in confinement

We study the spontaneous nucleation and growth of sodium chloride crystals induced by controlled evaporation in confined geometries (microcapillaries) spanning several orders of magnitude in volume. In all experiments, the nucleation happens reproducibly at a very high supersaturation S~1.6 and is independent of the size, shape and surface properties of the microcapillary. We show from classical nucleation theory that this is expected: S~1.6 corresponds to the point where nucleation first becomes observable on experimental time scales. A consequence of the high supersaturations reached at the onset of nucleation is the very rapid growth of a single skeletal (Hopper) crystal. Experiments on porous media reveal also the formation of Hopper crystals in the entrapped liquid pockets in the porous network and consequently underline the fact that sodium chloride can easily reach high supersaturations, in spite of what is commonly assumed for this salt.Comment: 16 pages, 6 figure

Courtship behaviour and vibrational communication of the planthopper Apartus michalki (Wagner, 1948): (Hemiptera: Fulgoromorpha: Cixiidae)

Paarungsverhalten und Vibrationskommunikation von Apartus michalki (Wagner, 1948) (Hemiptera: Fulgoromorpha: Cixiidae). – Cixiidae benötigen, wie alle sich sexuell reprodu- zierende Taxa, eine Reihe von Erkennungsmerkmalen, um potentielle Paarungspartner zu identifizieren und zu lokalisieren (specific mate recognition system = SMRS). Zwar ist der Einsatz von akustischen und/oder substratgebundenen Signalen als Teil des SMRS bei Hemipteren bekannt und weit verbreitet, die Kenntnisse zum Paarungsverhalten bei Cixiiden sind jedoch noch lückenhaft. In diesem Beitrag dokumentieren wir zum ersten Mal die Vibrationskommunikation bei Apartus michalki zusammen mit weiteren Beobachtungen zum Paarungsverhalten dieser Art.Cixiidae require a set of clues in order to recognize and localize potential conspecific partners for mating (specific mate recognition system = SMRS). The use of acoustic and/or vibrational signals as part of the SMRS is ubiquitous in Hemiptera. However, the general knowledge of the mating behaviour of Cixiidae is still patchy. Here we report for the first time evidence for vibrational communication in Apartus michalki along with observations of the courtship behaviour

The Intestinal Peptide Transporter PEPT1 Is Involved in Food Intake Regulation in Mice Fed a High-Protein Diet

High-protein diets are effective in achieving weight loss which is mainly explained by increased satiety and thermogenic effects. Recent studies suggest that the effects of protein-rich diets on satiety could be mediated by amino acids like leucine or arginine. Although high-protein diets require increased intestinal amino acid absorption, amino acid and peptide absorption has not yet been considered to contribute to satiety effects. We here demonstrate a novel finding that links intestinal peptide transport processes to food intake, but only when a protein-rich diet is provided. When mice lacking the intestinal peptide transporter PEPT1 were fed diets containing 8 or 21 energy% of protein, no differences in food intake and weight gain were observed. However, upon feeding a high-protein (45 energy%) diet, Pept1−/− mice reduced food intake much more pronounced than control animals. Although there was a regain in food consumption after a few days, no weight gain was observed which was associated with a reduced intestinal energy assimilation and increased fecal energy losses. Pept1−/− mice on high-protein diet displayed markedly reduced plasma leptin levels during the period of very low food intake, suggesting a failure of leptin signaling to increase energy intake. This together with an almost two-fold elevated plasma arginine level in Pept1−/− but not wildtype mice, suggests that a cross-talk of arginine with leptin signaling in brain, as described previously, could cause these striking effects on food intake

Metabolism of bile acids in the post-prandial state

The modulation of energy expenditure by dietary administration of cholic acid in mice promoted interest in studying bile acid(s) (BA) as adjuvants in the treatment of metabolic diseases such as obesity and diabetes. Bile acids can modulate intermediary metabolism by acting directly on nuclear as well as G-protein-coupled receptors or indirectly through changes in gut microbiota. Despite the potential of BA to affect intermediary metabolism, plasma kinetics and changes in individual BA in blood in the post-prandial state have been neglected for a long time. Minutes after ingestion of a meal (or a glucose challenge), the plasma BA concentration increases as a result of the secretion of bile into the duodenum, followed by intestinal absorption and a systemic circulation spillover. A large inter-individual variability of post-prandial kinetics of plasma BA is documented. Factors such as gender, diet composition, circadian oscillations, and individual capacities for the synthesis and transport of BA play important roles in determining this variability and are discussed in the present short review in light of new findings

La boxa, Clint i jo (I)

Abstract not availabl

How the Intestinal Peptide Transporter PEPT-1 Contributes to an Obesity Phenotype in Caenorhabditits elegans

Background: Amino acid absorption in the form of di- and tripeptides is mediated by the intestinal proton-coupled peptide transporter PEPT-1 (formally OPT-2) in Caenorhabditits elegans. Transporter-deficient animals (pept-1(lg601)) show impaired growth, slowed postembryonal development and major changes in amino acid status. Principal Findings: Here we demonstrate that abolished intestinal peptide transport also leads to major metabolic alterations that culminate in a two fold increase in total body fat content. Feeding of C. elegans with [U- 13 C]-labelled E. coli revealed a decreased de novo synthesis of long-chain fatty acids in pept-1(lg601) and reduced levels of polyunsaturated fatty acids. mRNA profiling revealed increased transcript levels of enzymes/transporters needed for peroxisomal b-oxidation and decreased levels for those required for fatty acid synthesis, elongation and desaturation. As a prime and most fundamental process that may account for the increased fat content in pept-1(lg601) we identified a highly accelerated absorption of free fatty acids from the bacterial food in the intestine. Conclusions: The influx of free fatty acids into intestinal epithelial cells is strongly dependent on alterations in intracellular pH which is regulated by the interplay of PEPT-1 and the sodium-proton exchanger NHX-2. We here provide evidence for a central mechanism by which the PEPT-1/NHX-2 system strongly influences the in vivo fat content of C. elegans. Loss of PEPT-1 decreases intestinal proton influx leading to a higher uptake of free fatty acids with fat accumulation whereas loss of NHX

Association between guidelines and medical practitioners' perception of best management for patients attending with an apparently uncomplicated acute sire throat: a cross-sectional survey in five countries

Objective To investigate the relationship between guidelines and the medical practitioners' perception of optimal care for patients attending with an apparently uncomplicated acute sore throat in five countries (Australia, Germany, Sweden, UK and USA). Design International cross-sectional survey. Setting Primary healthcare (PHC). Participants Medical practitioners working in PHC. Main outcome measures ORs for: (A) perception of throat swabs as important, (B) perception of blood tests (C reactive protein, B-ESR and B-leucocytes) as important and (C) antibiotic prescriptions if no pathogenic bacteria isolated on throat swab. Results Guidelines differed significantly; those recommending throat swabs (Sweden and USA) were associated with practitioners perceiving them as important. The UK guideline was the only one actively discouraging the use of throat swabs. Hence, compared with the USA (reference), a throat swab showing no pathogenic bacteria increased the probability of antibiotic prescribing in the UK with OR 3.2 (95% CI 1.7 to 6.1) for adults, whereas it reduced the probability in Sweden for adults OR 0.35 (95% CI 0.13 to 0.96) and children 0.19 (95% CI 0.069 to 0.50). Conclusions The differences between practitioners' perceptions of best management were associated with their guidelines. It remains unclear if guidelines influenced medical practitioners' perception or if guidelines merely reflect the consensus of current practice. A larger effort should be made to reach an international consensus in high-income countries about the best management of patients attending for an uncomplicated acute sore throat