Biochemical evidence of key residues for the activation and autoprocessing of tomato type II metacaspase.

To investigate the autolysis pattern and activation of metacaspase in higher plants, the biochemical characteristics of purified recombinant type II metacaspase (LeMCA1) from tomato were explored. Western blotting analysis indicated that four cleaved bands were formed; two N-terminal fragments and two C-terminal fragments. N-terminal sequencing confirmed that LeMCA1 cleaves at Lys223 and Arg332. Site mutants indicated that catalytic Cys139, cleaved Lys223, Arg332 and predicted calcium binding Asp116/Asp117 are the key residues that are responsible for its Ca²âº and pH dependent activation. The cleavage of the full-size fragment seemed crucial for the activation of LeMCA1 in vitro.

[Study on of deferrization mechanism of apoferritin and the effect of spectra variation with holoferritin].

The deferrization mechanism of apoferritin was established, and the spectra variation of apoferritin was compared with that of holoferritin. Sodium hyposulfite is a strong reducing agent, therefore, was applied to deoxidize holoferritin to release iron ion, and connection of iron of buffer was measured by the 2,2-dipyridyl. Apoferritin was detected by ICP-MS. Holoferritin was found to have no absorption compared with apoferritin by UV analysis, and have no fluorescence emission spectra in contrast with apoferritin by fluorescence analysis.

[A double labial-arch retaining appliance after correction of Class III osteal malocclusion].

A double labial-arch retaining appliance to retain the treatment effective of Class III osteal malocclusion were introduced and used to retain 60 patients with Class III osteal malocclusion. At the same time, 60 patients with Class III osteal malocclusion were retained with conventional Hawley retainer as the control group. The results indicated that the double labial-arch retaining appliance has good effect to the retain of Class III osteal malocclusion.

Biological properties of different protein extracts from selenium-enriched Ganoderma lucidum.

Our previous studies showed that Ganoderma lucidum bio-transformed 20-30% of inorganic selenium from substrate to organic forms by preferentially incorporating selenium into proteins. In the present study, four kinds of protein extracts from selenium-enriched G. lucidum were prepared with different extracting solvents, which contain water-soluble, alkaline-soluble, salt-soluble and alcohol-soluble protein extracts, and the effects on antioxidant activity of characterizations of protein extracts were studied. Results showed that water-soluble extract showed strongest antioxidant properties among all extracts as suggested by spin trapping experiment due to its characterizations, followed by the alkaline-soluble > the salt-soluble > the alcohol-soluble protein extracts, a result demonstrating that selenium content and amino acids composition of the protein extracts play important and direct roles in enhancing their antioxidant activities, and the protein distribution and sugar content have an indirect effect by influencing the characters and structures. The activity of water-soluble crude protein was verified by CuSO4 Phen-Vc-H2O2-DNA chemiluminescent analysis, and it should be selected as the subject to be studied and purified further.

Synthesis, characterization and biological activity of lanthanum(III) complexes containing 2-methylene-1,10-phenanthroline units bridged by aliphatic diamines.

Two novel lanthanum(III) complexes containing 2-methylene-1,10-phenanthroline units bridged by aliphatic diamines were synthesized and characterized by elemental analysis, IR, NMR, thermal analysis and conductance measurements. They have been assayed for anticancer activity in vitro against HL-60 (human leukocytoma) cells, PC-3MIE8 (human prostate carcinoma) cells, BGC-823 (human stomach carcinoma) cells, MDA-MB-435 (human galactophore carcinoma) cells, Bel-7402 (human liver carcinoma) cells, and Hela (human cervix carcinoma) cells. The results show that the two complexes exhibit good cytotoxic activities against different cell lines in general, especially more effective than cisplatin against Bel-7402, BGC-823 and MDA-MB-435 cell lines. DNA-binding studies indicate that, besides the intercalation, the complexes bind to DNA by the other interaction(s), which might be responsible for the production of more compact DNA, coinciding with more A-like feature of DNA as suggested by CD spectra.

Effect of Zn(II) on the structure and biological activity of natural beta-NGF.

Only beta-NGF, the subunit of the 7S NGF complex, exhibits NGF activity, but the function of the zinc ion in native beta-NGF has received little attention. Flameless atomic absorption spectroscopy (FAAS) measurements reveal that native beta-NGF contains Zn(II) with a Zn(II)/beta-NGF stoichiometry of 1:14.6. The presence of Zn(II) in the native molecule results in significant changes of the secondary structure and local tertiary structure around Trp(s) with respect to those of apo beta-NGF, as suggested by spectra of fluorescence and circular dichrosim. Stopped-flow studies show that there are at least two steps during the interaction of Zn(II) with the apo form. In comparison with its apo form, the native beta-NGF shows a higher ability to trigger the proliferation of TF1 cells and mediate the survival of PC12. Thus it is most likely that the structural changes caused by the presence of Zn(II) directly lead to the increase in the biological activity of beta-NGF. All results indicate that Zn(II) in native beta-NGF plays an important role in the structure and the biological activity of the protein.