Synthesis and unusual glycosidic coupling reaction of substituted 2,7-dioxabicyclo[4.1.0]heptanes: 1,2-anhydro-3,4-di-O-benzyl-alpha-D-fucopyranose.
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Carbohydrate Conformation↗
Biomedical subjects
F Kong
Publications and source records attributed to F Kong.
[Progress in plastic surgery in 1982-1994 in China].
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China↗
Identification and classification of Neisseria gonorrhoeae by RAPD fingerprinting.
Using the RAPD method, we identified and classified Neisseria gonorrhoeae on the basis of the DNA level. Except OPG20 the other 19 primers of OPG arbitrary primer kit showed informative arrays of amplified prominent segments. Most of the segments were common to all three Neisseria gonorrhoeae groups; some segments were amplified from two groups or only one group so that the fingerprint maps of different Neisseria gonorrhoeae groups were distinctive. Based on these findings, i.e. on the genomic level, we can classify the three Neisseria gonorrhoeae groups. Using OPG10 and OPG11 to amplify the five Neisseria species, we found marked diversity among them, which made it easy for us to identify Neisseria gonorrhoeae from four other Neisseria species. The use of the RAPD method needs some special reaction conditions, e.g. annealing temperature that should not be too low or too high and should be consistently stable. The quality of Taq polymerase is also very important. The reproducibility of the results under these conditions was very good.
Base Sequence↗
[Measurement of respiratory muscle performance in patients with chronic obstructive pulmonary disease].
Respiratory muscle performance is measured in terms of strength and endurance. A RMSE-1 type measuring system for evaluation of respiratory muscle strength (RMS) and endurance (RME) has been developed and tested in normal subjects and patients with stable chronic obstructive pulmonary disease (COPD). The results showed that there was no significant difference between normal subjects and stable COPD patients in RMS measured as maximum inspiratory pressure (MIP) and maximum expiratory pressure (MEP). The maximum load (Load(m)), mean mouth pressure at maximum load (Pmean), and the maximum sustainable inspiratory pressure (SIP(m)) as % MIP (SIP(m)/MIP) were taken as measure of RME. All measures of RME in COPD group were much lower than those in the normal. The measurement of RME can be used to evaluate the effect of respiratory muscle training and direct the respiratory rehabilitation in COPD patients.
Adult↗
The crystal structure and conformational analysis of substituted 2,7-dioxabicyclo[4,1,0]heptanes: 1,2-anhydro-3,4,6-tri-O-benzyl-beta-D-talopyranose.
The title compound, C28H27O5, is triclinic, space group P1 with unit cell dimensions a = 12.763(2), b = 11.130(2), c = 4.764(3) A, alpha = 73.78(3), beta = 82.89(3), gamma = 62.16(1) degrees, V = 574.8(4) A3, and Z = 1. The pyranose ring has an 4H5 conformation with some flattening at C-4. Molecular mechanisms calculations indicate that the 4H5 conformation of the pyranose ring in the title compound is the most stable conformation.
Carbohydrate Conformation↗
Synthesis, conformational analysis, and the glycosidic coupling reaction of substituted 2,7-dioxabicyclo[4.1.0]heptanes: 1,2-anhydro-3,4-di-O-benzyl-beta-L- and beta-D-rhamnopyranoses.
1,2-Anhydro-3,4-di-O-benzyl-alpha-L-rhamnopyranose was synthesized from L-rhamnose, while the D-enantiomer was synthesized from methyl 6-deoxy-2,3-O-isopropylidene-alpha-D-mannopyranoside. For both of the syntheses, the key intermediates were 2-O-acetyl-3,4-di-O-benzyl-alpha-D- and -alpha-L-rhamnopyranosyl chlorides that were quantitatively prepared from the corresponding diacetates by chlorination. Ring closure of the chlorides was carried out readily with potassium tert-butoxide in oxolane, and crystalline 1,2-anhydro-3,4-di-O-benzyl-beta-D- and beta-L-rhamnopyranose were obtained in high yields. Conformational calculations, which were carried out using vicinal proton-proton coupling constants by the modified Karplus equation, suggested that the conformations of the pyranose rings of the title compounds were basically a half chair (4H5) with some flattening at C-4. Force-field calculations (MMP2) confirmed the experimental conformation with good agreement. The coupling reaction of the 1,2-anhydro-L-rhamnose ether with 1,2;3,4-di-O-isopropylidene-alpha-D-galactopyranose was effected in oxolane by catalysis by a Lewis acid, and only the alpha-linked disaccharide was obtained.
Antigens, Bacterial↗
The impact of unemployment and economic stress on social support.
Two waves of questionnaire data obtained from displaced workers are used to test whether continuous unemployment (vs. reemployment) and increased economic stress influence displaced workers' perceptions of social support for a period of one to nine months following job loss from a plant closing. Two kinds of effects, stability and change, in these variables are examined. The results demonstrate change in social support after job loss, which indicates that unemployment and social support are mutually related and that life events (continuous unemployment) have an impact on social support through economic distress. Findings point to the need for further research on the issue of stress-buffering mechanisms.
Adult↗
[Revelations of the origin of Chinese nation from clustering analysis and frequency distribution of HLA polymorphism in major minority nationalities in mainland China].
This paper is a joint report on the analysis of polymorphism of HLA class I, II and III antigens in Chinese major minority nationalities (Miao, Buyi, Mongol of Inner Mongolia, Man, Hui, Tibetan and Uygur), and southern and northern Han samples as a part of the workshop organized by the 11th International Histocompatibility Workshop and Conference (IHWC) held on 6-13 November 1991 in Yokohama. Clustering analysis showed that Miao and Buyi cluster with the southern Han and Mongol, Man, Hui and Tibetan cluster around the northern Han, suggesting that the Chinese nation comprises northern and southern two major populations. Uygur clusters with a large group of Caucasoid samples from very far point. Frequencies of HLA alleles of Caucasoid origin (A3, B8 and others) decrease eastwards and southwards, and those of HLA alleles of Southeast Asia Mongoloid origin (B46 and others) decrease northwards. The gradient distribution of HLA allele frequencies suggests the unceasing migration and mutual amalgamation of our ancestors since the remote pre-historic times. From the fact that Chinese nation comprises northern and southern two major populations, this paper discussed the possible revelations of the origin of Chinese nation.
Asian People↗
[Location of ctDNA fragment related to CMS in Brassica napus L. var. xiangai].
The ctDNA of sterile line and its maintainer from Brassica napus L. var. xiangai were digested by restriction endonucleases EcoRI, BamHI, PstI and SmaI. Only one special fragment E3.2kb was observed in EcoRI restriction pattern of maintainer. After being eluted, this fragment was incubated with plasmid pUC9 and then transformed E. coli JM83. Through colour screening, clony hybridization and electrophoretic analyses, the special clone carrying E3.2 was obtained. The rRNA gene probe was used to hybridize with the EcoRI restriction pattern. The result showed that E3.2kb fragment is homologous to rRNA gene. And then, we use E3.2 fragment as probe to hybridize with rRNA gene digested by BamHI, EcoRI, SalII, BglII, HindIII and PstI. According to rRNA gene map, E3.2 fragment was located at the leader sequence of 16S rRNA gene, from +2.0kb to +5.4kb. Because this 3.4kb region was in the inverted repeat region of ctDNA and it is homologous to E3.2kb that related to CMS. So probably CMS is related to this 3.4kb region in the inverted repeat region of ctDNA.
Brassica↗
[Sequence and primary structure analysis of specific DNA fragment related to pollen fertility in radish chloroplast genome].
Nucleotide sequence of a radish chloroplast BafHI-EcoRI fragment (ZL1) derived from B21, which is related to cytoplasmic male sterility and also found in radish 401B retaining line, has been determined. The results show that this fragment is 474bp in length, and is rich in AT base components. The nucleotide sequence of ZL1 has 96.6% homology as compared with the corresponding sequence of tobacco which is located at the positions from 142330 to 142803 in IRA and from 100199 to 99726 in IRB in the tobacco chloroplast genome. It seems that ZL1 contains part of rps7-rps12 operon and encodes 7 of amino acid residues of C-terminal of rps12 as well as 93 residues of N-terminal of rps7. The secondary structure of the partial intron from 1 to 119 in ZL1 was deduced by computer. This three stemloop structure is very similar to that of maize reported by Giese, and it has the CONSENSUS sequence of the Group II intron. The deduced amino acid sequence of S7 in ZL1 shows 95.7, 79.6, 69.9, 40.9, 36.6 and 46.2% and that of S12 shows more than 70% homology compared with the corresponding sequences of tobacco, maize, liverwort, E. gracilis, E. coli and cyanobacterium respectively. The results imply that chloroplast ribosomal proteins may play a role in cytoplasmic male sterility in higher plants.
Base Sequence↗
The stereochemical requirement for protein kinase C activation by 3-methyldiglycerides matches that found in naturally occurring tumor promoters aplysiatoxins.
Protein kinase C is stereospecifically activated by sn-1,2-(S)-diglycerides. A second chiral center was introduced into the diglycerides by preparing the 3-methyl derivatives. The activation of protein kinase C was also stereospecific with respect to the new chiral center established at the C3 position of the methylated diglycerides. The stereospecifically of protein kinase C directed towards the C2 and C3 positions of the diglycerides is matched in the analogous C29 and C30 stereocenters of the tumor promoting debromoaplysiatoxins. This finding strengthens the view that the structurally diverse tumor promotors contain the embedded diglyceride-like pharmacophore.
Animals↗