133 research outputs found
Survie en milieu insulaire : quelle stratégie ? Le cas des mésanges en Corse
The breeding biology and demography of Blue tit (Parus
caeruleus) and Coal tit (Parus ater) populations of southern France
and Corsica were compared from 1976 to 1980. The following
differences between the mainland and the island populations
were found :
1. The onset of the breeding season is delayed in Corsica,
egg-laying beginning three to four weeks later than on the mainland.
2. The clutch-size is smaller on the island, the clutch averaging
three more eggs on the mainland
3. The mortality of the nestlings is also much higher in
Corsica than in southern France, due to heavy parasitism by
Trypocalliphora sp. and food shortage which cause heavy mortality.
4. However, the survival rate of adult tits is higher in
Corsica than on the mainland.
5. Contrary to what is the rule in southern France, Corsican
tits do not apparently breed at the time of maximum food
abundance.
The demographic strategies of the Corsican populations of
Blue and Coal tits are apparently K-selected
Caractérisation moléculaire des procaryotes et facteurs de variation des écosystÚmes digestifs chez deux mammifÚres herbivores : approche comparée vache/lapin
Lâobjectif de ce travail Ă©tait de caractĂ©riser la variabilitĂ© spĂ©cifique (Bos taurus vs Oryctolagus cuniculus), individuelle, spatiale (inter- et intra- fermenteurs digestifs) et temporelle (en conditions non perturbĂ©e ou perturbĂ©e) des Ă©cosystĂšmes digestifs des mammifĂšres herbivores (communautĂ©s procaryotiques et biotope) en comparant deux modĂšles animaux, la vache et le lapin, et en utilisant des outils molĂ©culaires (CE-SSCP et qPCR). Dâun point de vue mĂ©thodologique, nous avons dĂ©veloppĂ© un programme informatique, StatFingerprints, pour amĂ©liorer le traitement et lâanalyse statistique des profils CE-SSCP et ainsi mieux extraire lâinformation Ă©cologique quâils contiennent en termes de structure et de diversitĂ© des communautĂ©s. Nous avons Ă©galement mis au point des systĂšmes de qPCR plus spĂ©cifiques (Firmicutes et Bacteroides Prevotella) que ceux prĂ©cĂ©demment dĂ©crits. Dâun point de vue cognitif, nos travaux dĂ©montrent une forte influence de lâespĂšce hĂŽte sur les caractĂ©ristiques de son Ă©cosystĂšme : les communautĂ©s sont plus riches (+8 %, +12 % pour les bactĂ©ries et les Archaea, respectivement), plus diverse (+19 % pour les bactĂ©ries) mais moins abondantes (-4.9 % de bactĂ©ries) dans le rumen de la vache que dans le caecum du lapin. Le biotope ruminal est moins acide (+0.6 unitĂ© pH), plus rĂ©ducteur (-30 mV), et contient moins dâacides gras volatils (-19%) et plus de NH3-N (+39%) que le biotope caecal. Cela suggĂšre un rĂŽle dĂ©terminant de la physiologie digestive de lâhĂŽte et/ou des phĂ©nomĂšnes de coĂ©volution hĂŽte/microbiote. Nos travaux nâont pas permis de mettre en Ă©vidence un effet de « lâindividu hĂŽte » sur les caractĂ©ristiques de sa communautĂ© microbienne suggĂ©rant que la proximitĂ© gĂ©nĂ©tique entre les individus (race) et/ou la forte standardisation des conditions dâĂ©levage (logement, alimentation etc.) tendent Ă uniformiser lâinfluence des individus sur le dĂ©terminisme de leurs communautĂ©s procaryotiques. Nous avons montrĂ© quâil existe une Ă©volution des communautĂ©s microbiennes le long du tractus digestif en relation avec la physiologie et les conditions environnementales des diffĂ©rents compartiments Ă laquelle sâadditionne, dans le rumen, une variabilitĂ© liĂ©e Ă la fraction, liquide ou solide, considĂ©rĂ©e. Nos donnĂ©es suggĂšrent quâĂ lâĂ©tat basal et en situation de perturbation, les communautĂ©s procaryotiques des deux espĂšces hĂŽtes nâĂ©voluent pas de la mĂȘme façon dans le temps. Ainsi, dans le rumen de la vache, la communautĂ© bactĂ©rienne fluctue de façon sporadique suggĂ©rant un Ă©tat dâĂ©quilibre dynamique alors quâelle reste dans un Ă©tat dâĂ©quilibre statique dans le caecum du lapin. Les deux communautĂ©s rĂ©agissent de façon rapide(\u3c 2jours) et sâadaptent rapidement Ă une augmentation du ratio amidon/fibres pour atteindre un nouvel Ă©quilibre, dynamique dans le rumen et statique dans le caecum. En revanche, nos travaux nâont pas mis en Ă©vidence de corrĂ©lations importantes entre les communautĂ©s bactĂ©riennes et les paramĂštres de leur environnement. Dâun point de vue finalisĂ©, ces donnĂ©es confirment que la nutrition est une voie dâaction pertinente pour essayer de rĂ©orienter le fonctionnement des Ă©cosystĂšmes digestifs chez ces espĂšces dâintĂ©rĂȘt zootechnique, vers une meilleure santĂ© et/ou efficacitĂ© digestive. ABSTRACT : The aim of this work was to characterize the specific (Bos taurus vs Oryctolagus cuniculus), individual, spatial (inter- and intra- digestive fermentors) and temporal (in undisturbed or disturbed conditions) variability of the digestive ecosystems (prokaryotic communities and biotope) in herbivorous mammals by comparing two animal models, cow and rabbit, and by using molecular methods (CE-SSCP and qPCR). Concerning methodology, we developed the StatFingerprints program to improve processing and statistical analysis of CE-SSCP profiles and better extract ecological information they contained about structure and diversity of communities. We also developed more specific (Firmicutes and Bacteroides Prevotella) primers than those available. From a cognitive point of view, our work demonstrated a strong effect of host species on ecosystem: communities presented a higher richness (+8 %, +12 % for bacteria and Archaea, respectively), a greater diversity (+19 % for bacteria) but are less abundant (-4.9 % bacteria) in cow rumen than in rabbit caecum. The rumen biotope is less acid (+0.6 pH unit), more reductive (-30 mV), and contains a lower concentration of fatty acids (-19%) and a higher concentration of NH3-N (+39%) than caecal biotope. Taken together, these results suggested a determining role of the digestive physiology of the host and of coevolution phenomena between the host and its microbiota. Our results did not permit to evidence an individual effect on the procaryotic communities suggesting that the genetic similarity between animals we used and/or the strong standardization of breeding conditions (housing, food etc) tended to reduce the influence of the individuals on their prokaryotic communities. We showed that the procaryotic communities evolved along the digestive tract in relation to the physiology and the environmental conditions of the various compartments in which they live. In addition, in the rumen, we evidenced a variability of the bacterial community related to the fraction considered, liquid or solid. Our data suggested that, both in basal and disturbed situations, the bacterial communities of the two host species did not evolve in the same way in time. Indeed, in the rumen of the cow and basal condition, the bacterial community fluctuated sporadically suggesting a dynamic balance whereas it remains in a stable state in the caecum of the rabbit. The two communities reacted quickly (\u3c 2 days) and adapted quickly to an increased ratio starch/fibres to reach a new balance, dynamic in the rumen and stable in the caecum. On the other hand, our work did not highlight important correlations between the bacterial communities and the parameters of their environments. From a finalized point of view, these data confirmed that the nutrition is a relevant way to try to reorientate the functioning of digestive ecosystems in these two species, toward a better digestive health and/or efficiency
Starch and oil in the donor cow diet and starch in substrate differently affect the in vitro ruminal biohydrogenation of linoleic and linolenic acids
Trans isomers of fatty acids exhibit different health properties. Among them, trans-10,cis-12 conjugated linoleic acid has negative effects on milk fat production and can affect human health. A shift from the trans-11 to the trans-10 pathway of biohydrogenation (BH) can occur in the rumen of dairy cows receiving high-concentrate diets, especially when the diet is supplemented with highly unsaturated fat sources. The differences of BH patterns between linoleic acid (LeA) and linolenic acid (LnA) in such ruminal conditions remain unknown; thus, the aim of this work was to investigate in vitro the effects of starch and sunflower oil in the diet of the donor cows and starch level in the incubates on the BH patterns and efficiencies of LeA and LnA. The design was a 4 Ă 4 Latin square design with 4 cows, 4 periods, and 4 diets with combinations of 21 or 34% starch and 0 or 5% sunflower oil. The rumen content of each cow during each period was incubated with 4 substrates, combining 2 starch levels and either LeA or LnA addition. Capillary electrophoresis single-strand conformation polymorphism of incubates showed that dietary starch decreased the diversity of the bacterial community and the high-starch plus oil diet modified its structure. High-starch diets poorly affected isomerization and first reduction of LeA and LnA, but decreased the efficiencies of trans-11,cis-15-C18:2 and trans C18:1 reduction. Dietary sunflower oil increased the efficiency of LeA isomerization but decreased the efficiency of trans C18:1 reduction. An interaction between dietary starch and dietary oil resulted in the highest trans-10 isomers production in incubates when the donor cow received the high-starch plus oil diet. The partition between trans-10 and trans-11 isomers was also affected by an interaction between starch level and the fatty acid added to the incubates, showing that the trans-10 shift only occurred with LeA, whereas LnA was mainly hydrogenated via the more usual trans-11 pathway, whatever the starch level in the substrate, although the bacterial communities were not different between LeA and LnA incubates. In LeA incubates, trans-10 isomer production was significantly related to the structure of the bacterial community
Analyse comparée des écosystÚmes digestifs du rumen de la vache et du caecum du lapin
Dans cette revue nous avons synthĂ©tisĂ© les donnĂ©es obtenues dans notre Ă©quipe et celles de la bibliographie afin de contribuer Ă une meilleure connaissance de lâĂ©cologie des communautĂ©s bactĂ©riennes et archĂ©es des fermenteurs digestifs des mammifĂšres herbivores. Lâanalyse a portĂ© sur la comparaison des deux principales stratĂ©gies digestives rencontrĂ©es chez les mammifĂšres herbivores actuels :
un fermenteur en position proximale, le rumen, et un fermenteur en position distale, le caecum. Parmi les espĂšces dâintĂ©rĂȘt agronomique,la vache et le lapin on Ă©tĂ© choisis comme animaux modĂšles. AprĂšs avoir rappelĂ© les caractĂ©ristiques anatomiques et physicochimiques de ces fermenteurs digestifs, nous avons analysĂ© les spĂ©cificitĂ©s de leurs communautĂ©s procaryotiques liĂ©es Ă lâhĂŽte, la variabilitĂ© individuelle, la structuration spatiale (inter- et intra- fermenteurs digestifs) et la dynamique temporelle (journaliĂšre et hebdomadaire) avec ou sans perturbation nutritionnelle induite
Quantitative Proteomic Approach Reveals Altered Metabolic Pathways in Response to the Inhibition of Lysine Deacetylases in A549 Cells under Normoxia and Hypoxia.
Growing evidence is showing that acetylation plays an essential role in cancer, but studies on the impact of KDAC inhibition (KDACi) on the metabolic profile are still in their infancy. Here, we analyzed, by using an iTRAQ-based quantitative proteomics approach, the changes in the proteome of KRAS-mutated non-small cell lung cancer (NSCLC) A549 cells in response to trichostatin-A (TSA) and nicotinamide (NAM) under normoxia and hypoxia. Part of this response was further validated by molecular and biochemical analyses and correlated with the proliferation rates, apoptotic cell death, and activation of ROS scavenging mechanisms in opposition to the ROS production. Despite the differences among the KDAC inhibitors, up-regulation of glycolysis, TCA cycle, oxidative phosphorylation and fatty acid synthesis emerged as a common metabolic response underlying KDACi. We also observed that some of the KDACi effects at metabolic levels are enhanced under hypoxia. Furthermore, we used a drug repositioning machine learning approach to list candidate metabolic therapeutic agents for KRAS mutated NSCLC. Together, these results allow us to better understand the metabolic regulations underlying KDACi in NSCLC, taking into account the microenvironment of tumors related to hypoxia, and bring new insights for the future rational design of new therapies
Effect of different weaning age (21, 28 or 35 days) on production, growth and certain parameters of the digestive tract in rabbits
The effect of different weaning ages, that is, 21 (G21), 28 (G28) or 35 (G35) days, on growth and certain parameters of the
digestive tract was examined in rabbits to assess the risk of early weaning attributable to the less-developed digestive system.
On days 35 and 42, G35 rabbits had 10% to 14% and 10% higher BW, respectively ( P,0.05), than those weaned at days 21 and
28. In the 4th week of life, early weaned animals had 75% higher feed intake than G28 and G35 rabbits ( P,0.05). The relative
weight of the liver increased by 62% between 21 and 28 days of age, and thereafter it decreased by 76% between 35 and
42 days of age ( P,0.05), with G21 rabbits having 29% higher weight compared with G35 animals on day 35 ( P,0.05).
The relative weight of the whole gastrointestinal (GI) tract increased by 49% and 22% after weaning in G21 and G28 rabbits,
respectively ( P,0.05). On day 28, the relative weight of the GI tract was 19% higher in G21 than in G28 rabbits, whereas on day
35 G21 and G28 animals had a 12% heavier GI tract compared with G35 rabbits ( P,0.05). Age influenced the ratio of stomach,
small intestine and caecum within the GI tract; however, no effect of different weaning age was demonstrated. The pH value of
the stomach and caecum decreased from 5.7 to 1.6 and from 7.1 to 6.3, respectively, whereas that of the small intestine increased
from 6.8 to 8.4 ( P,0.05); the differences between groups were not statistically significant. Strictly anaerobic culturable bacteria
were present in the caecum in high amounts (108), already at 14 days of age; no significant difference attributable to weaning age
was demonstrable. The concentration of total volatile fatty acids (tVFA) was higher in G21 than in G28 and G35 throughout the
experimental period ( P,0.05). The proportion of acetic and butyric acid within tVFA increased, whereas that of propionic acid
decreased, resulting in a C3 : C4 ratio decreasing with age. Early weaning (G21) resulted in higher butyric acid and lower propionic
acid proportions on day 28 ( P,0.05). No interaction between age and treatment was found, except in relative weight of the GI
tract and caecal content. In conclusion, early weaning did not cause considerable changes in the digestive physiological
parameters measured, but it resulted in 10% lower growth in rabbits
Materials in particulate form for tissue engineering. 1 Basic concepts
For biomedical applications, materials small in size are growing in importance. In an era where
ânanoâ is the new trend, micro- and nano-materials are in the forefront of developments. Materials in
the particulate form aim to designate systems with a reduced size, such as micro- and nanoparticles.
These systems can be produced starting from a diversity of materials, of which polymers are the
most used. Similarly, a multitude of methods are used to produce particulate systems, and both
materials and methods are critically reviewed here. Among the varied applications that materials
in the particulate form can have, drug delivery systems are probably the most prominent, as these
have been in the forefront of interest for biomedical applications. The basic concepts pertaining
to drug delivery are summarized, and the role of polymers as drug delivery systems conclude this
review
Le <i>Journal de Lyon</i> (1784-1792). Un périodique provincial à la fin du siÚcle des LumiÚres
Le Journal de Lyon est un périodique de province de la fin de l'Ancien Régime qui dure jusqu'en 1791-1792. Ce mémoire s'attache à montrer de quelle maniÚre il occupe une place particuliÚre dans le milieu de la presse locale lyonnaise, comment il est ancré dans un cercle de lettrés lyonnais, et la façon dont il est représentatif de l'esprit des LumiÚres. Les premiÚres années de la Révolution eurent des conséquences importantes sur lui
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