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Danielle E. Haulsee Dewayne A. Fox Matthew W. Breece Tonya M. Clauss Matthew J. Oliver 《PloS one》2016,11(2)
We developed a long-term tagging method that can be used to understand species assemblages and social groupings associated with large marine fishes such as the Sand Tiger shark Carcharias taurus. We deployed internally implanted archival VEMCO Mobile Transceivers (VMTs; VEMCO Ltd. Nova Scotia, Canada) in 20 adult Sand Tigers, of which two tags were successfully recovered (10%). The recovered VMTs recorded 29,646 and 44,210 detections of telemetered animals respectively. To our knowledge, this is the first study to demonstrate a method for long-term (~ 1 year) archival acoustic transceiver tag implantation, retention, and recovery in a highly migratory marine fish. Results show low presumed mortality (n = 1, 5%), high VMT retention, and that non-lethal recovery after almost a year at liberty can be achieved for archival acoustic transceivers. This method can be applied to study the social interactions and behavioral ecology of large marine fishes. 相似文献
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The photoacoustic (PA) characteristics (energy storage and heat dissipation) of photosystem II (PSII) core-enriched particles from barley were studied (i) in conditions where there was electron flow, i.e., in the presence of a combination of the electron acceptor K3 Fe (CN)6, referred to as FeCN, and the electron donor diphenylcarbazide (DPC), and (ii) in conditions where electron flow was suppressed, i.e., in the absence of FeCN and DPC. The experimental data show that a decrease of heat dissipation with a minimum at 540 nm can be interpreted as energy storage resulting from the presence of pheophytin (Pheo) in the PSII particles. On account of the capability of the PA method to measure the energy absorbed by the chromophores which is converted to heat, it is suggested that the PA detection of Pheo present in the PSII complex will permit to clarify the function of processes involving non-radiative relaxation of excited states in P680-Pheo-QA interactions.Abbreviations -Car
-Carotene
- Chl
Chlorophyll
- DPC
Diphenylcarbazide
- EPR
Electron Paramagnetic Resonance
- FeCN
potassium ferricyanide
- HEPES
N-2-hydroxyethylenepiperazine-N-2-ethanesulfonate
- P680
reaction center of PSII
- PA
Photoacoustic
- Pheo
pheophytin
- PSI
photosystem I
- PSII
photosystem II
- QA
primary electron acceptor of PSII 相似文献
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The mechanism of melibiose symport by the melibiose permease of Escherichia coli was studied by looking at the modifications of the facilitated diffusion properties of the permease which arise upon substitution of the coupled cations (H+, Na+, or Li+). Kinetic analysis of melibiose influx and efflux down a concentration gradient, exchange at equilibrium, and counterflow were examined in de-energized membrane vesicles resuspended in media allowing melibiose to be co-transported with either H+, Na+, or Li+. The data show that the maximal rates of melibiose efflux coupled to either H+, Na+, or Li+ are between 10 and 40 times faster than the corresponding influxes. This suggests that the permease functions asymmetrically. Cross-comparison between the rates of net [3H]melibiose entry during the influx reactions coupled to either cation and corresponding unidirectional sugar inflow during exchange and counterflow reactions leads to the conclusions that: 1) the step involving release of the co-substrates from the permease on the inner surface of the membrane is sequenced (sugar first and then coupled cation); 2) this step is rate determining for cycling of the permease. The Na+-melibiose passive flux data indicate in particular that release of Na+ ions rather than release of sugar into the intravesicular space is the slowest step during permease cycling. This property would hamper net passive Na+-melibiose influx but should allow exchange of sugar without concomitant exchange of the coupled cation. Finally, evidence is provided suggesting that the relative rates of release of the two co-substrates from the permease on the inner membrane surface varied considerably in relation to the identity of the coupled cation. 相似文献
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Danielle L. Laval-Martin Isabelle A. Carr Saverio J. Barbera Leland N. Edmunds 《Chronobiology international》1990,7(2):99-105
-We have previously shown that NAD kinase and NADP phosphatase activities display circadian rhythms, in the soluble (SN) and membrane-bound (P) fractions of crude extracts of the achlorophyllous ZC mutant of the phytoflagellate Euglena gracilis (which displays circadian rhythmicity of cell division). We determined if changes in the affinity of NADP phosphatase and NAD kinase for their substrates, NADP+ and NAD+, were occurring by calculating the ratios 100(velocity found in Km conditions/velocity found in saturating conditions). The rationale was that if the affinity remained unchanged according to circadian time (CI), these values should always equal 50, independently of any changes in enzyme quantity; values greater than 50 should indicate increases in enzyme affinity, and values less than 50 decreases in affinity. Our results indicated that these values calculated for NADP phosphatase exhibited a complex pattern of rhythmicity, while those for NAD kinase displayed circadian variations strongly correlated with the rhythms in enzyme activity. The curves showed troughs at CT 00-04 both in dividing and nondividing cells and peaks at CT 18-20 or at CT 08-14 in cells sampled, respectively, from a dividing or a stationary culture. Such variations are indicative of changes in the kinetic properties of the enzyme, which may reflect modifications in its affinity either for effectors (such as Ca2+-calmodulin) or for its substrate, NAD+. This may be due to (i) the expression of different isoenzymes at different CTs; (ii) different posttranslational modifications of the enzyme; or (iii) concentrations of effectors varying in a circadian manner. 相似文献