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Robert R. Rojas Richard E. Lee Tuan-Anh Luu John G. Baust 《Journal of insect physiology》1983,29(11):865-869
Temperature effects on antifreeze metabolism were investigated in two populations (northern and southern) of the golden rod gallfly, Eurosta solidaginis. Sorbitol production was temperature dependent and was triggered by short-term exposure to < +10°C. The maximal rate sorbitol synthesis occurred at 0°C. For both populations, sorbitol was rapidly catabolized during warm acclimation at +20°C. During the first 12 h of warm acclimation, sorbitol levels decreased by 36% (19.7 ± 0.6) to 12.6 ± 1.2 μg/mg) and by 83% (to 3.3 ± 1.7 μg/mg) after 48 h in the northern population. The southern population decreased sorbitol levels 64% (11.8 ± 0.69 to 4.2 ± 0.62) after 48 h. The southern population resynthesized more sorbitol than did the northern population upon re-exposure to 0°C. Glycerol levels increased linearly during the experimental period independent of temperature. 相似文献
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Purification and characterization of minor brain proteolipids: use of fast atom bombardment-mass spectrometry for peptide sequencing 总被引:2,自引:0,他引:2
P Lepage G Helynck J Y Chu B Luu O Sorokine E Trifilieff A Van Dorsselaer 《Biochimie》1986,68(5):669-686
A combination of lipophilic gel permeation chromatography and ion-exchange chromatography in organic solvents was used to purify low molecular weight proteolipids from bovine brain. Cleavage peptides were purified by HPLC and studied mainly by the fast atom bombardment--mass spectrometry technique. A proteolipid of Mr 14 000 contains several peptides from the first 113 amino acids of the major myelin proteolipid (MMPL) plus an extra unknown blocked N-terminal peptide. A proteolipid of Mr 16 000 contains smaller peptides belonging to a C-terminal fragment of MMPL of about 160 residues. These two proteolipids do not seem to be artifacts from MMPL. 相似文献
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Nitrilotriacetate Stimulation of Anaerobic Fe(III) Respiration by Mobilization of Humic Materials in Soil
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An enrichment culture capable of naphthalene mineralization reduced Fe(III) oxides without direct contact in anaerobic soil microcosms when the Fe(III) was placed in dialysis membranes or entrapped within alginate beads. Both techniques demonstrated that a component in soil, possibly humic materials, facilitated Fe(III) reduction when direct contact between cells and Fe(III) was not possible. The addition of the synthetic Fe(III) chelator, nitrilotriacetic acid (NTA), to soil enhanced Fe(III) reduction across the dialysis membrane and alginate beads, with the medium changing from clear to a dark brown color. An NTA-soil extract was more effective in Fe(III) reduction than the extracted soil itself. Characteristics of the NTA extract were consistent with that of humic substances. The results indicate that NTA improved Fe(III) reduction not by Fe(III) solubilization but by extraction of humic substances from soil into the aqueous medium. This is the first study in which stimulation of Fe(III) reduction through the addition of chemical chelators is shown to be due to the extraction of electron-shuttling compounds from the soil and not to solubilization of the Fe(III) and indicates that mobilization of humic materials could be an important component of anaerobic biostimulation. 相似文献
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