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81.
82.
Matt K. Broadhurst Camila Domit Tailisi H. Trevizani Vincent Raoult Russell B. Millar 《Journal of fish biology》2019,95(2):589-593
We determined stable-isotope ratios for replicate muscle tissues in 13 gravid Mobula kuhlii cf. eregoodootenkee (110.4–120.4 cm disc width; WD) and their embryos (7.0–42.3 cm WD) and also yolks and histrotroph, to assess the potential implications for juvenile nutrition and habitat use. Irrespective of their development in the uterus, embryos had similar δ13C values in their muscle tissue as the mothers and both had greater values than in the histotroph. During gestation, δ13C values increased across all sample types. However, while embryo muscle tissue and the histotroph were associated with increasing 15N levels during embryonic development, this was depleted in the mothers’ muscle tissue and yolk. Although speculative, the observed variation in stable-isotope ratios might imply a dietary shift among gravid females during their early gestation. Irrespective of the underlying mechanisms, the results indicate neonates will have relatively greater δ15N values than post-partum females, which would probably confound juvenile foraging-ecology estimates. 相似文献
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86.
The Circadian Clock Gene Circuit Controls Protein and Phosphoprotein Rhythms in Arabidopsis thaliana
Johanna Krahmer Matthew Hindle Laura K. Perby Helle K. Mogensen Tom H. Nielsen Karen J. Halliday Gerben van Ooijen Thierry Le Bihan Andrew J. Millar 《Molecular & cellular proteomics : MCP》2022,21(1):100172
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87.
Jocelyn K. Middlemiss rea M. Anderson Chad W. Stratilo Harold G. Weger 《Journal of phycology》2001,37(3):393-399
Plasma membrane ferric reductase activity was enhanced 5-fold under iron limitation in the unicellular green alga Chlorella kessleri Fott et Nováková. Furthermore, ferric reductase activity in iron-limited cells was approximately 50% higher in the light than in the dark. In contrast, iron uptake rates of iron-limited cells were unaffected by light versus dark treatments. Rates of iron uptake were much lower than rates of ferric reduction, averaging approximately 2% of the dark ferric reduction rate. Ferric reduction was associated with an increased rate of O2 consumption in both light and dark, the increase in the light being approximately 1.5 times as large as in the dark. The increased rate of O2 consumption could be decreased by half by the addition of catalase, indicating that H2 O2 is the product of the O2 consumption and that the increased O2 consumption is nonrespiratory. The stimulation of O2 consumption was almost completely abolished by the addition of bathophenanthroline disulfonate, a strong chelator of Fe2 + . Anaerobic conditions or the presence of exogenous superoxide dismutase affected neither ferric reduction nor iron uptake. We suggest that the O2 consumption associated with ferric reductase activity resulted from superoxide formation from the aerobic oxidation of Fe2 + , which is the product of ferric reductase activity. At saturating concentrations of Fe3 + chelates, ferric reductase activity is much greater than the iron uptake rate, leading to rapid oxidation of Fe2 + and superoxide generation. Therefore, O2 consumption is not an integral part of the iron assimilation process. 相似文献
88.
89.
Molecular properties of 4-substituted indole-3-acetic acids affecting pea pericarp elongation 总被引:3,自引:0,他引:3
Dennis M. Reinecke Jocelyn A. Ozga Nebojša Ilić Volker Magnus Biserka kojić-Prodić 《Plant Growth Regulation》1999,27(1):39-48
Pea (Pisum sativum L.) fruit naturally contain the auxins, indole-3-acetic acid (IAA) and 4-chloroindole-3-acetic acid (4-Cl-IAA). However, only 4-Cl-IAA can substitute for the seeds in maintaining pea fruit growth in planta. The importance of the substituent at the 4-position of the indole ring was tested by comparing the molecular properties of 4-X-IAA (X = H, Me, Et, F, or Cl) and their effect on the elongation of pea pericarps in planta. Structure-activity is discussed in terms of structural data derived from X-ray analysis, computed conformations in solution, semiempirical shape and bulk parameters, and experimentally determined lipophilicities and NH-acidities. The size of the 4-substituent, and its lipophilicity are associated with growth promoting activity of pea pericarp, while there was no obvious relationship with electromeric effects. 相似文献
90.
Stark RM Gerwig GJ Pitman RS Potts LF Williams NA Greenman J Weinzweig IP Hirst TR Millar MR 《Letters in applied microbiology》1999,28(2):121-126
Helicobacter pylori NCTC 11637 produces a water-insoluble biofilm when grown under defined conditions with a high carbon:nitrogen ratio in continuous culture and in 10% strength Brucella broth supplemented with 3 g l-1 glucose. Biofilm accumulated at the air/liquid interface of the culture. Light microscopy of frozen sections of the biofilm material showed few bacterial cells in the mass of the biofilm. The material stained with periodic acid Schiff's reagent. Fucose, glucose, galactose, and glycero-manno-heptose, N-acetylglucosamine and N-acetylmuramic acid were identified in partially purified and in crude material, using gas chromatography and mass spectrometry. The sugar composition strongly indicates the presence of a polysaccharide as a component of the biofilm material. Antibodies (IgG) to partially purified material were found in both sero-positive and sero-negative individuals. Treatment of the biofilm material with periodic acid reduced or abolished immunoreactivity. Treatment with 5 mol l-1 urea at 100 degrees C and with phenol did not remove antigenic recognition by patient sera. The production of a water-insoluble biofilm by H. pylori may be important in enhancing resistance to host defence factors and antibiotics, and in microenvironmental pH homeostasis facilitating the growth and survival of H. pylori in vivo. 相似文献