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81.
Cadmium stimulates the accumulation of salicylic acid and its putative precursors in maize (Zea mays) plants 总被引:1,自引:0,他引:1
Magda Pál Eszter Horváth Tibor Janda Emil Páldi Gabriella Szalai 《Physiologia plantarum》2005,125(3):356-364
The effect of 10, 25 and 50 µ M Cd(NO3 )2 on the salicylic acid (SA) metabolism was investigated in young maize seedlings ( Zea mays L., hybrid Norma). Cadmium (Cd) was translocated into the leaves and induced oxidative damage, as indicated by the reduced chlorophyll content, the decreased quantum efficiency of photosystem II and the enhanced malondialdehyde (MDA) content, especially after 7 days. The activity of glutathione reductase (EC 1.6.4.2) increased from the fourth day and that of guaiacol peroxidase (EC 1.11.1.7) after 7 days of Cd stress compared with the control leaves. These effects of Cd exhibited a correlation with the concentration. Under these conditions, Cd did not affect the MDA content or the antioxidant enzyme activities in the roots. After 7 days, Cd increased the levels of free and bound forms of benzoic acid (BA), O -coumaric acid ( O -hydroxy-cinnamic) ( O- HCA) and SA in the leaves, but in the roots, only the 50 µ M rate of Cd caused changes in the free O -HCA acid and bound BA content. 相似文献
82.
Cody J. Wenthur Xiaoqing Cai Beverly A. Ellis Kim D. Janda 《Bioorganic & medicinal chemistry letters》2017,27(16):3666-3668
Given the need for further improvements in anti-cocaine vaccination strategies, a chimeric hapten (GNET) was developed that combines chemically-stable structural features from steady-state haptens with the hydrolytic functionality present in transition-state mimetic haptens. Additionally, as a further investigation into the generation of an improved bifunctional antibody pool, sequential vaccination with steady-state and transition-state mimetic haptens was undertaken. While GNET induced the formation of catalytically-active antibodies, it did not improve overall behavioral efficacy. In contrast, the resulting pool of antibodies from GNE/GNT co-administration demonstrated intermediate efficacy as compared to antibodies developed from either hapten alone. Overall, improved antibody catalytic efficiency appears necessary to achieve the synergistic benefits of combining cocaine hydrolysis with peripheral sequestration. 相似文献
83.
Oliver Brümmer Changshou Gao Shenlan Mao David P. Weiner Kim D. Janda 《Letters in Peptide Science》1999,6(5-6):295-302
The design, synthesis and characterization of a new class of metal complexes (panning agents) for the selection of antibodies from a combinatorial library are described. The metal panning agents contain a phosphorodithioate moiety that binds soft metals, leaving them coordinatively unsaturated. Subsequent panning against an antibody phage library selects for members that recognize, and bind directly to, the metal rather than ligands attached to the metal. 相似文献
84.
85.
J. Michael Janda Sharon L. Abbott David Woodward Shideh Khashe 《Current microbiology》1998,37(3):159-165
Wild-type strains of Providencia species were evaluated for their ability to invade HEp-2 monolayers based upon microscopic and semi-quantitative assays.
Of 14 P. alcalifaciens strains tested, 3 (17%) were found to be highly invasive, 4 (22%) moderately invasive, and the remaining 61% weakly or noninvasive.
HEp-2 invasion results were confirmed by thin-section electron microscopy. Invasive capabilities of P. alcalifaciens were greater at higher MOIs (100 to 1000) than at lower inocula (<10 MOI). No strain of P. stuartii or P. rettgeri tested invaded HEp-2 cells. Quantitative assays of Triton X-100-lysed, HEp-2-invaded cells indicated that between 0.001%
and 0.013% of the initial bacterial inoculum was gentamicin resistant. Further testing of select strains on various cell lines
indicated the efficiency of invasion was Vero > Y1 > INT-407 > HEp-2. Two isolates recovered from a father and son with prolonged
diarrhea after returning from Mexico were found to be identical on the basis of biotype, serotype, and genotype. These results
provide additional evidence that some P. alcalifaciens strains cause gastroenteritis.
Received: 1 December 1997 / Accepted: 25 March 1998 相似文献
86.
J Janda 《The Biochemical journal》1971,124(5):73P-74P
87.
Investigation of the quaternary structure of beef liver glutamate dehydrogenase with bifunctional reagents 总被引:2,自引:0,他引:2
The six identical polypeptide chains of the smallest enzymatically active unit of beef liver glutamate dehydrogenase are shown to be arranged in two trimers. Cross-linking with bifunctional reagents of varying chain length and subsequent SDS polyacrylamide gel electrophoresis of the protein shows main bands corresponding to molecular weights of 168,000 and 336,000 daltons which is three times and six times, respectively, the molecular weight of the polypeptide chain (56,000 daltons). This finding supports a model for the quaternary structure of the glutamate dehydrogenase proposed by Reisler and Eisenberg (Biopolymers , 877 (1970)). 相似文献
88.
Salicylic acid (SA) is a phenolic phytohormone with important roles in plant development, transpiration, endogenous signaling and defense against pathogens. One of the pathways of SA biosynthesis is located in the chloroplasts. The aim of the present work was to investigate the possible regulatory effects of SA on photosynthetic electron transport processes. Here we show that SA also affects leaf photosynthesis, via inducing stomatal closure and also by slowing down Photosystem II (PS II) electron transport. Photosynthetic CO? incorporation and stomatal conductivity (measured with an infrared gas analyzer) were much lower in SA-infiltrated tobacco leaves than in untreated or water-infiltrated controls. PS II electron transport (calculated from PAM chlorophyll fluorescence data) was more sensitive to SA than Photosystem I (PS I) (measured with far red absorption). Direct probing of PS II charge separation and stabilization (measured with thermoluminescence), however, showed that these events were less affected in isolated thylakoid membranes than in leaves, suggesting that the effect of SA on PS II is indirect and different from similar effects of phenolic herbicides. 相似文献
89.
Apostol S Szalai G Sujbert L Popova LP Janda T 《Zeitschrift für Naturforschung. C, Journal of biosciences》2006,61(9-10):734-740
The effect of irradiance during low temperature hardening was studied in a winter wheat variety. Ten-day-old winter wheat plants were cold-hardened at 5 degrees C for 11 days under light (250 micromol m(-2) S(-1)) or dark (20 micromol m(-2) s(-1)) conditions. The effectiveness of hardening was significantly lower in the dark, in spite of a slight decrease in the Fv/Fm chlorophyll fluorescence induction parameter, indicating the occurrence of photoinhibition during the hardening period in the light. Hardening in the light caused a downshift in the far-red induced AG (afterglow) thermoluminescence band. The faster dark re-reduction of P700+, monitored by 820-nm absorbance, could also be observed in these plants. These results suggest that the induction of cyclic photosynthetic electron flow may also contribute to the advantage of frost hardening under light conditions in wheat plants. 相似文献
90.
Anna Stochmal Iwona Kowalska Bogdan Janda Angela Perrone Sonia Piacente Wiesaw Oleszek 《Phytochemistry》2009,70(10):1272-1276
Three phenolic glycosides 5-O-{[5′′-O-E-(4′′′-O-threo-guaiacylglycerol)-feruloyl]-β-apiofuranosyl-(1→2)-β-xylopyranosyl} gentisic acid, 5-O-[(5′′-O-vanilloyl)-β-apiofuranosyl-(1→2)-β-xylopyranosyl] gentisic acid and 1-O-[E-(4′′′-O-threo-guaiacylglycerol)-feruloyl]-3-O-β-galacturonopyranosyl glycerol were isolated and identified from the roots of Medicago truncatula together with four known 5-O-β-xylopyranosyl gentisic acid, vicenin-2, hovetrichoside C and pterosupin identified for the first time in this species. Structural elucidation was carried out on the basis of UV, mass, 1H and 13C NMR spectral data. 相似文献