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M Vianeyliaud - One of the best experts on this subject based on the ideXlab platform.
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study of the diet effect on δ13c of shell carbonate of the land snail helix aspersa in experimental conditions
Earth and Planetary Science Letters, 2003Co-Authors: S Metref, Denisdidier Rousseau, I Bentaleb, Maylis Labonne, M VianeyliaudAbstract:This study aims to demonstrate the influence of the metabolic CO2 derived from the diet and of the atmospheric CO2 on the shell carbonate N 13 C of the pulmonate snail Helix aspersa maxima raised under controlled conditions. Adult snails were analyzed and compared with three hatching and 1-day old young snails stemming from the same breeding. One day after, the 2-day old individuals were raised during 1 month. Three groups of gastropods were fed with fresh lettuce (C3 Plant, N 13 C= 327.49x), three groups with corn (C4 Plant, N 13 C= 311.7x), and three groups ate alternately both (C3+C4). The difference between the average N 13 C values of the adult snails on the one hand and the hatched and 1-day old snails on the other hand indicates a depletion of 2.47x. Therefore, the isotopic parents^ offspring signal is not preserved. The depleted ingested albumen by the snail embryo in the egg during the building of the shell could explain this depletion. The C3 diet experiment gave the expected isotopic composition difference
Denisdidier Rousseau - One of the best experts on this subject based on the ideXlab platform.
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study of the diet effect on δ13c of shell carbonate of the land snail helix aspersa in experimental conditions
Earth and Planetary Science Letters, 2003Co-Authors: S Metref, Denisdidier Rousseau, I Bentaleb, Maylis Labonne, M VianeyliaudAbstract:This study aims to demonstrate the influence of the metabolic CO2 derived from the diet and of the atmospheric CO2 on the shell carbonate N 13 C of the pulmonate snail Helix aspersa maxima raised under controlled conditions. Adult snails were analyzed and compared with three hatching and 1-day old young snails stemming from the same breeding. One day after, the 2-day old individuals were raised during 1 month. Three groups of gastropods were fed with fresh lettuce (C3 Plant, N 13 C= 327.49x), three groups with corn (C4 Plant, N 13 C= 311.7x), and three groups ate alternately both (C3+C4). The difference between the average N 13 C values of the adult snails on the one hand and the hatched and 1-day old snails on the other hand indicates a depletion of 2.47x. Therefore, the isotopic parents^ offspring signal is not preserved. The depleted ingested albumen by the snail embryo in the egg during the building of the shell could explain this depletion. The C3 diet experiment gave the expected isotopic composition difference
Lowell D Stott - One of the best experts on this subject based on the ideXlab platform.
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the influence of diet on the δ13c of shell carbon in the pulmonate snail helix aspersa
Earth and Planetary Science Letters, 2002Co-Authors: Lowell D StottAbstract:The influence of diet and atmospheric CO2 on the carbon isotope composition of shell aragonite and shell-bound organic carbon in the pulmonate snail Helix aspersa raised in the laboratory was investigated. Three separate groups of snails were raised on romaine lettuce (C3 Plant, δ13C=−25.8‰), corn (C4 Plant, δ13C=−10.5‰), and sour orange (12C-enriched C3 Plant, δ13C=−39.1‰). The isotopic composition of body tissues closely tracked the isotopic composition of the snail diet as demonstrated previously. However, the isotopic composition of the acid insoluble organic matrix extracted from the aragonite shells does not track diet in all groups. In snails that were fed corn the isotopic composition of the organic matrix was more negative than the body by as much as 5‰ whereas the matrix was approximately 1‰ heavier than the body tissues in snails fed a diet of C3 Plant material. These results indicate that isotopic composition of the organic matrix carbon cannot be used as an isotopic substrate for paleodietary reconstructions without first determining the source of the carbon and any associated fractionations. The isotopic composition of the shell aragonite is offset from the body tissues by 12.3‰ in each of the culture groups. This offset was not influenced by the consumption of carbonate and is not attributable to the diffusion of atmospheric CO2 into the hemolymph. The carbon isotopic composition of shell aragonite is best explained in terms of equilibrium fractionations associated with exchange between metabolic CO2 and HCO3 in the hemolymph and the fractionation associated with carbonate precipitation. These results differ from previous studies, based primarily on samples collected in the field, that have suggested atmospheric carbon dioxide contributes significantly to the shell δ13C. The culture results indicate that the δ13C of aragonite is a good recorder of the isotopic composition of the snail body tissue, and therefore a better recorder of diet than is the insoluble shell organic carbon. Because the systematic fractionation of carbon isotopes within the snail is temperature dependent, the δ13C of the shell could provide an independent technique for estimating paleotemperature changes.
S Metref - One of the best experts on this subject based on the ideXlab platform.
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study of the diet effect on δ13c of shell carbonate of the land snail helix aspersa in experimental conditions
Earth and Planetary Science Letters, 2003Co-Authors: S Metref, Denisdidier Rousseau, I Bentaleb, Maylis Labonne, M VianeyliaudAbstract:This study aims to demonstrate the influence of the metabolic CO2 derived from the diet and of the atmospheric CO2 on the shell carbonate N 13 C of the pulmonate snail Helix aspersa maxima raised under controlled conditions. Adult snails were analyzed and compared with three hatching and 1-day old young snails stemming from the same breeding. One day after, the 2-day old individuals were raised during 1 month. Three groups of gastropods were fed with fresh lettuce (C3 Plant, N 13 C= 327.49x), three groups with corn (C4 Plant, N 13 C= 311.7x), and three groups ate alternately both (C3+C4). The difference between the average N 13 C values of the adult snails on the one hand and the hatched and 1-day old snails on the other hand indicates a depletion of 2.47x. Therefore, the isotopic parents^ offspring signal is not preserved. The depleted ingested albumen by the snail embryo in the egg during the building of the shell could explain this depletion. The C3 diet experiment gave the expected isotopic composition difference
A N Tikhonov - One of the best experts on this subject based on the ideXlab platform.
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regulation of electron transport in C3 Plant chloroplasts in situ and in silico short term effects of atmospheric co2 and o2
Biochimica et Biophysica Acta, 2011Co-Authors: Ilya V Kuvykin, Vasily V Ptushenko, A V Vershubskii, A N TikhonovAbstract:Abstract In this work, we have investigated the effects of atmospheric CO2 and O2 on induction events in Hibiscus rosa-sinensis leaves. These effects manifest themselves as multiphase kinetics of P700 redox transitions and non-monotonous changes in chlorophyll fluorescence. Depletion of CO2 and O2 in air causes a decrease in linear electron flux (LEF) and dramatic lowering of P700+ level. This is explained by the impediment to electron efflux from photosystem 1 (PS1) at low acceptor capacity. With the release of the acceptor deficit, the rate of LEF significantly increases. We have found that oxygen promotes the outflow of electrons from PS1, providing the rise of P700+ level. The effect of oxygen as an alternative electron acceptor becomes apparent at low and ambient concentrations of atmospheric CO2 (≤0.06–0.07%). A decrease in LEF at low CO2 is accompanied by a significant (about 3-fold) rise of non-photochemical quenching (NPQ) of chlorophyll fluorescence. Such an increase in NPQ can be explained by more significant acidification of the thylakoid lumen. This occurs due to lessening the proton flux through the ATP synthases caused by a decrease in the ATP consumption in the Bassham–Benson–Calvin (BBC) cycle. pH-dependent mechanisms of electron transport control have been described within the frames of our mathematical model. The model describes the reciprocal changes in LEF and NPQ and predicts the redistribution of electron fluxes on the acceptor side of PS1. In particular, the contribution of cyclic electron flow around PS1 (CEF1) and water–water cycle gradually decays during the induction phase. This result is consistent with experimental data indicating that under the steady-state conditions the contribution of CEF1 to photosynthetic electron transport in Hibiscus rosa-sinensis is insignificant (≤ 10%).