The subjects were all Chinese male adults. The average age, body weight and height were 37.9 (24-44) yr, 64.3 (51.5-74.0) kg and 173 (157-180) cm respectively in the first group, and 30.2 (24-41) yr, 67.7 (56.5-70.0) kg and 171 (170-176) cm respectively in the second group.The subjects in the first group were studied for 70 days for the N balance response at graded protein intakes of 0.42, 0.60, 0.73, 0.90 and 1.05 g/kg /day on Chinese mixed diet, during 5 experimental periods respectively. Each period took ten days preceded by one day of low protein diet, and was followed by three days of free choice diet The sequence of protein intakes during the study was 0.60, 0.73, 0.42, 0.90 and 1.05 g/kg/day. Six subjects in the second group were given a mixed diet ata protein level of 0.93 (0.91-0.94) g/kg/day for three months.In the N balance data of the first group, all subjects were in negative balance at protein intake of 0.42, 0.60 and 0.73 g/kg/day and all in positive N balance at 1.05 g/kg/day. Most of the subjects were in positive N balance at 0.90 g/kg/day. The linear regression analysis of N balance response of individual subject is that the intercept at zero balance of individuals ranged from 129.4-192.5 mg N/kg/day with the mean of the group of 147.7? 18.6mg N/kg/day or 0.92?0.12 g protein/kg/day. The five of the six subjects in the second group were in positive N balance, when on a mixed diet of 0.93 ?0.02 g protein/kg/day for three months.The results obtained indicated the mean protein requirement of these subjects based on the linear regression analysis of N balance response of individuals was 147.7 ? 18.6 mg N/kg/day or 0.92?0.12 g protein/kg/day. If 97.5% is to be covered, the safe level of protein intake should be 1.16 g protein/ kg/day.

Twenty kinds of amino acids are simplified into 3 types: hydrophobic amino acids (H), hydrophilic amino acids (P) and neutral amino acids (N). Each residue is reduced to a bead which locates in the position of the C?琢 atom. The off-lattice model is adopted and the relative entropy is used as a minimization function to predict the tertiary structure of a protein. A new contact intensity function is given to consist with protein design research based on the relative entropy. Testing on several real proteins from Protein Data Bank (PDB) shows the good results obtained with the model and method. The root mean square deviations (RMSD) of the predicted structures relative to the native structures range from 0.30 to 0.70 nm. A foundation for studying protein design using the HNP model and the relative entropy was made.

The application of the protein design method based on the HNP model and the relative entropy theory is discussed for four structural classes of real proteins, and the results are compared with that of the HP model. Testing on 190 proteins shows that this method is generally effective for the different structural classes of proteins. Further studies show that the success rate of this method on regular secondary structures is higher than that on the random coil. Additionally, the success rate for different types of amino acids is also analyzed. It is found that the success rate on the hydrophilic residues is higher than those of the other two types. Furthermore, the success rate of this method on the conserved residues is higher than the non-conserved residues. The reasons resulting in the difference of the success rate on different systems were also analyzed. All analyses mentioned above make the foundation for the development and the application of this method in the future.

[ ABSTRACT] AIM:To observe the influences of different concentrations of MG132 on apoptosis and beta-amyloid protein ( Aβ) generation in SH-SY5Y cells, and to explore the underlying mechanism.METHODS:SHSY-5Y cells were incubated with MG132 for 24 h.The final concentrations of MG132 were 2.5, 5 and 10μmol/L.The cell viability was de-termined by MTT assay.The cell apoptosis was assessed by flow cytometry.The levels of Aβwere measured by ELISA. The relative protein levels were detected by Western blot.RESULTS:In the SH-SY5Y cells, MG132 reduced the cell via-bility, induced the cell apoptosis, increased the level of Aβ, and increased the expression of the related proteins for Aβgeneration in a concentration-dependent manner.CONCLUSION: MG132 induces apoptosis and increases the levels of Aβ1-42 and Aβ1-40 by regulating the proteins related to Aβgeneration in the SH-SY5Y cells.

A group of SARS-Iike coronaviruses(SL-CoV)have been identified in horseshoe bats.Despite SL-CoVs and SARS-CoV share identical genome structure and high-level sequence similarity,SL-CoV does not bind to the same cellular receptor as for SARS-CoV and the N-terminus of the S proteins only share 64% amino acid identity,suggesting there are fundamental differences between these two groups of coronaviruses.To gain insight into the basis of this difference,we established a recombinant adenovirus system expressing the S protein from SL-CoV(rAd-Rp3-S)to investigate its immune characterization.Our results showed that immunized mice generated strong humoral immune responses against the SL-CoV S protein.Moreover,a strong cellular immune response demonstrated by elevated IFN-γ and IL-6 levels was also observed in these mice.However,the induced antibody from these mice had weaker cross-reaction with the SARS-CoV S protein,and did not neutralize HIV pseudotyped with SARS-CoV S protein.These results demonstrated that the immunogenicity of the SL-CoV S protein is distinct from that of SARS-CoV,which may cause the immunological differences between human SARS-CoV and bat SL-CoV.Furthermore,the recombinant virus could serve as a potential vaccine candidate against bat SL-CoV infection.

The growth curves and diet of 185 babies in rural area near Beijing from 6 months to 18 months old have been studied. Infants were divided into 3 groups according to their diet taken:(1) 89 babies had breast milk only;(2) 66 babies took more than 250g animal milk per day besides breast milk;(3) 30 babies who did not have breast milk and only animal milk was taken. All the babies were gradually transferred to an ordinary cereal based diet during the weaning period. To half of them a soybean and cereal based formula fortified with minerals and vitamins was supplied, which would provide 6.6g protein and 141 kcal and some other nutrients per day.The results showed that the growth curves of body weight and height of children were much better than the data obtained in 1975, but still lagged behind that of the urban children, especially for the body weight. The weight curves of the babies who took animal milk seemed higher than the other groups. Female babies who were fed with breast milk and supplemented with the weaning food have a better weight and height curves than non-supplemented ones, but this was not seen in males. The hemoglobin contents of the babies who took animal milk when they were 18 months old were lower than that of the 6 months old, but there were no differences in the breast milk groups, and the lowering of the hemoglobin level in the animal milk groups could be corrected by adding weaning food in the diet. When the babies were 6 months old, 39.3% of them had a hair zinc content below the lower limit of the normal range, and it became to 47.6% when they were 18 months old. So zinc deficiency of the babies were present in this local area, and it should be fortified into the weaning food.