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Yu H Karunakaran KP Kelly I Shen C Jiang X Foster LJ Brunham RC 《Journal of immunology (Baltimore, Md. : 1950)》2011,186(6):3615-3621
Mice that were intranasally vaccinated with live or dead Chlamydia muridarum with or without CpG-containing oligodeoxynucleotide 1862 elicited widely disparate levels of protective immunity to genital tract challenge. We found that the frequency of multifunctional T cells coexpressing IFN-γ and TNF-α with or without IL-2 induced by live C. muridarum most accurately correlated with the pattern of protection against C. muridarum genital tract infection, suggesting that IFN-γ(+)-producing CD4(+) T cells that highly coexpress TNF-α may be the optimal effector cells for protective immunity. We also used an immunoproteomic approach to analyze MHC class II-bound peptides eluted from dendritic cells (DCs) that were pulsed with live or dead C. muridarum elementary bodies (EBs). We found that DCs pulsed with live EBs presented 45 MHC class II C. muridarum peptides mapping to 13 proteins. In contrast, DCs pulsed with dead EBs presented only six MHC class II C. muridarum peptides mapping to three proteins. Only two epitopes were shared in common between the live and dead EB-pulsed groups. This study provides insights into the role of Ag presentation and cytokine secretion patterns of CD4(+) T effector cells that correlate with protective immunity elicited by live and dead C. muridarum. These insights should prove useful for improving vaccine design for Chlamydia trachomatis. 相似文献
34.
Parul Gupta Kamal Dhawan Sarla P Malhotra Randhir Singh 《Acta Physiologiae Plantarum》2000,22(4):433-438
A trypsin inhibitor from seeds of faba bean (Vicia faba L.) was purified to near homogeneity as judged by native-PAGE with about 11 % recovery using ammonium sulphate fractionation,
ion-exchange chromatography on DEAE-cellulose and gel filtration through Sephadex G-100. The inhibitor had a molecular weight
of 18 kD as determined by SDS-PAGE and Sephadex G-100. The inhibitor inhibited trypsin and chymotrypsin to the extent of 48
and 12 %, respectively. The inhibtion was of non-competitive type with dissociation constant for the enzyme inhibitor complex
in the region of 0.07 mg·ml−1. The inhibtor was stable between pH 4 and 5. It completely lost its activity when heated at 125 °C for 1 h or at 100 °C for
2 h. The inhibitor also lost its activity on exposure to 2-mercaptoethanol. Based on these properties, it could be concluded
that Vicia faba trypsin inhibitor belongs to Bowman-Birk type of inhibitors, as it has molecular weight lower than generally observed for
Kunitz type inhibitors. 相似文献
35.
Leaf water potential was decreased by withholding irrigation to provide three levels of stress described as mild ({ie69-1}) moderate ({ie69-2}) and severe ({ie69-3}). The specific activity of NADP linked glyceraldehyde-3-phosphate dehydrogenase, phosphoglycerate kinase, aldolase, phosphogluco-isomerase and RuBP carboxylase decreased under mild stress, but the activity of phosphoglucomutase showed an increase whilst ribulose-5-phosphate kinase was least affected. With further decrease in water potential, the activity of NADP linked glyceraldehyde-3-phosphate dehydrogenase and aldolase showed a decrease, whereas, the activities of fructose-1,6-bisphosphatase, phosphoglycerate kinase, phosphogulcomutase and RuBP carboxylase increased. Net CO2 fixation decreased sharply with stress, whereas, respiration and photorespiration increased in moderate stress, but decreased under severe stress. Stomatal resistance also increased with decrease in water potential. It seems that in vitro enzyme activities of PCR cycle are not responsible for decreased photosynthesis in pigeonpea under short term water stress. 相似文献
36.
Ammonia assimilatory and ureide biogenic enzymes were measured in the cytosol fraction of pigeonpea nodules during the period
15–120 days after sowing. The activity of enzymes involved in the initial assimilation of ammonia, i.e. glutamine synthetase,
glutamate synthase, asparagine synthetase and aspartate aminotransferase, substantially increased activities during the period
of plant growth and reached a maximum value around 105 days after sowing. These increases paralleled the increase in nodule
mass, nitrogenase activity and ureide content in nodules. Though no regular pattern was obtained for their specific activities,
yet these activities when expressed relative to the specific activity of nitrogenase were many fold higher at each stage of
development. Similar increases were observed in the activities of enzymes associated with the formation of ureides from purines.
In almost all cases, the activities were again maximum around 90–105 days after sowing. The specific activities of nucleotidase,
nucleosidase, xanthine dehydrogenase, uricase and allantoinase, when expressed relative to the specific activity of nitrogenase
at vegetative, flowering and podsetting stages were again many fold higher indicating the sufficiency of the levels of these
enzymes for the biosynthesis of ureides. The data presented are consistent with the proposal that in ureide producing legumes,
ammonia is initially assimilated into glutamine, aspartate, etc., which are metabolised for the denovo synthesis of purines. The purines are then utilised for the production of ureides by a group of enzymes investigated here 相似文献
37.
Fruiting structures of a number of legumes including chickpea are known to carry out photosynthetic CO2 assimilation, but the pathway of CO2 fixation and particularly the role of phosphoenolpyruvate carboxylase (EC 4.1.1.31) in these tissues is not clear. Activities of some key enzymes of the Calvin cycle and C4 metabolism, rates of 14CO2 fixation in light and dark, and initial products of photosynthetic 14CO2 fixation were determined in podwall and seedcoat (fruiting structures) and their subtending leaf in chickpea (Cicer arietinum L.). Compared to activities of ribulose-1,5-bisphosphate carboxylase (EC 4.1.1.39) and other Calvin cycle enzyme, viz. NADP+-glyceraldehyde-3-phosphate dehydrogenase (EC 1.2.1.13), NAD+-glyceraldehyde-3-phosphate dehydrogenase (EC 1.2.1.12) and ribulose-5-phosphate kinase (EC 2.7.1.19), the levels of phosphoenolpyruvate carboxylase and other enzymes of C4 metabolism viz. NADP+-malate dehydrogenase (EC 1.1.1.82), NAD+-malate dehydrogenase (EC 1.1.1.37), NADP+ malic enzyme (EC 1.1.1.40), NAD+-malic enzyme (EC 1.1.1.39), glutamate oxaloacetate transaminase (EC 2.6.1.1) and glutamate pyruvate transaminase (EC 2.6.1.2), were generally much higher in podwall and seedcoat than in the leaf. Podwall and seedcoat fixed 14CO2 in light and dark at much higher rates than the leaf. Short-term assimilation of 14CO2 by illuminated fruiting structures produced malate as the major labelled product with less labelling in 3-phosphoglycerate, whereas the leaf showed a major incorporation into 3-phosphoglycerate. It seems likely that the fruiting structures of chickpea utilize phosphoenolpyruvate carboxylase for recapturing the respired carbon dioxide. 相似文献
38.
Intact amyloplasts from endosperm of developing wheat grains have been isolated by first preparing the protoplasts and then
fractionating the lysate of the protoplasts on percoll and ficoll gradients, respectively. Amyloplasts isolated as above were
functional and not contaminated by cytosol or by organelles likely to be involved in carbohydrate metabolism. The enzyme distribution
studies indicated that ADP-glucose pyrophosphorylase and starch synthase were confined to amyloplasts, whereas invertase,
sucrose synthase, UDP-glucose pyrophosphorylase, hexokinase, phosphofructokinase-2 and fructose-2,6-P2ase were absent fro the amyloplast and mainly confined to the cytosol. Triose-P isomerase, glyceraldehyde-3-P dehydrogenase,
phosphohexose isomerase, phosphoglucomutase, phosphofructokinase, aldolase, PPi-fructose-6-P-1 phosphotransferase, and fructose-l,6-P2ase, though predominantly cytosolic, were also present in the amyloplast. Based on distribution of enzymes, a probable pathway
for starch biosynthesis in amyloplasts of developing wheat grains has been proposed. 相似文献
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