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81.
Repeated Biogel P6 chromatography of the urine from a patient with fucosidosis yielded several fractions containing fucosyloligosaccharides and glycopeptides. Two of these were shown by 1H nuclear magnetic resonance (1H-n.m.r.) spectroscopy and permethylation analysis to have the following structures respectively: (I) αfuc (1→3) [βgal (1→4)] βglcNAc (1→2) αman (1→36) βman (1→4) glcNAc and (II) αfuc (1→3) [βgal (1→4)] βglcNAc (1→2) αman (1→36) βman (1→4) βglcNAc (1→4) [αfuc (1→36)] βglcNAc-Asn.  相似文献   
82.
7β,8α-Dihydroxy-9α,10α-epoxy-7,8,9,10-tetrahydrobenzo[a]pyrene (BP diolepoxide, 1) and 1-pyrenyloxirane (2) bind chemically to calf thymus DNA. The fluorescence efficiency of pyrenyl groups in mutagen modified DNA varies appreciably with its conformation and decreases in the order: pyrenees, modified denatured DNA and modified native DNA. A particularly interesting observation is that the fluorescence efficiency of mutagen modified DNA intensifies substantially upon denaturation. Our results suggest that the pyrenyl groups in mutagen modified DNA are intercalated between the base pairs of DNA. Since both 1 and 2 are powerful frame-shifting mutagens for S. typhimurium TA-98, the intercalative covalent binding of these compounds to DNA may provide a molecular basis for their mutagenic activity.  相似文献   
83.
The red marine algae Microcladia borealis, M. californica and M. coulteri produce several unusual halogenated monoterpenes including violacene, plocamene-B, plocamene-C, and plocamane-D. The isolation of these terpenes along with a study of their variation in each Microcladia at different locations are described.  相似文献   
84.
Incubating and shaking Staphylococcus aureus in liquid whole egg causes a decline in viability. During the period of agitation, the natural pH of the egg rises from about 7.2 to between 8.0 and 8.2 as a result of a loss of carbon dioxide. However, if the pH of the egg is prevented from rising, either by not shaking or by addition of a buffer, S. aureus will grow. The cause of death is traced to the presence of lysozyme of egg white. Interestingly, the action of lysozyme is not attributable to its bacterial lytic property but, instead, to the basicity of the lysozyme molecule. This conclusion is supported by the fact that the lytic property of lysozyme is known to have its optimal activity near neutrality and by the finding that protamine sulfate, a nonenzymatic basic polypeptide, also caused death of S. aureus at pH 8.0 but not at 7.0. It was postulated that the rise in pH renders the bacterial cells more negatively charged, so that in the presence of positively charged molecules like lysozyme or protamine sulfate a complex is formed, agglutinating the cells.  相似文献   
85.
The nonglycolytic, anaerobic organism Veillonella parvula M4 has been shown to contain an active pyruvate kinase. The enzyme was purified 126-fold and was shown by disc-gel electrophoresis to contain only two faint contaminating bands. The purified enzyme had a pH optimum of 7.0 in the forward direction and exhibited sigmoidal kinetics at varying concentrations o-f phosphoenol pyruvate (PEP), adenosine 5'-monophosphate (AMP), and Mg-2+ ions with S0.5 values of 1.5, 2.0, and 2.4 mM, respectively. Substrate inhibition was observed above 4 m PEP. Hill plots gave slope values (n) of 4.4 (PEP), 2.8 (adenosine 5'-diphosphate), and 2.0 (Mg-2+), indicating a high degree of cooperativity. The enzyme was inhibited non-competitively by adenosine 5'-triphosphate (Ki = 3.4 mM), and this inhibition was only slightly affected by increasing concentration of Mg-2+ ions to 30 mM. Competitive inhibition was observed with 3-phosphoglycerate, malate, and 2,3-diphosphoglycerate but only at higher inhibitor concentrations. The enzyme was activated by glucose-6-phosphate (P), fructose-6-P, fructose-1,6-diphosphate (P2), dihydroxyacetone-P, and AMP; the Hill coefficients were 2.2, 1.8, 1.5, 2.1, and 2.0, respectively. The presence of each these metabolites caused substrate velocity curves to change from sigmoidal to hyperbolic curves, and each was accompanied by an increase in the maximum activity, e.g., AMP greater than fructose-1,6-P2 greater than dihydroxyacetone-P greater than glucose-6-P greater than fructose-6-P. The activation constants for fructose-1,6-P2, AMP, and glucose-6-P were 0.3, 1.1, and 5.3 mM, respectively. The effect of 5 mM fructose-1,6-P2 was significantly different from the other compounds in that this metabolite was inhibitory between 1.2 and 3 mM PEP. Above this concentration, fructose-1,6-P2 activated the enzyme and abolished substrate inhibition by PEP. The enzyme was not affected by glucose, glyceraldehyde-3-P, 2-phosphoglycerate, lactate, malate, fumerate, succinate, and cyclic AMP. The results suggest that the pyruvate kinase from V. parvula M4 plays a central role in the control of gluconeogenesis in this organism by regulating the concentration of PEP.  相似文献   
86.
Perchloric acid extracts of radiation-induced fibrosarcoma (RIF-1) tumors grown in mice have been analyzed by multinuclear NMR spectroscopy and by various chromatographic methods. This analysis has permitted the unambiguous assignment of the 31P resonances observed in vivo to specific phosphorus-containing metabolites. The region of the in vivo spectra generally assigned to sugar phosphates has been found in RIF-1 tumors to contain primarily phosphorylethanolamine and phosphorylcholine rather than glycolytic intermediates. Phosphocreatine was observed in extracts of these tumor cells grown in culture as well as in the in vivo spectra, indicating that at least some of the phosphocreatine observed in vivo arises from the tumor itself and not from normal tissues. In the 31P-NMR spectra of the perchloric acid extract, resonances originating from purine and pyrimidine nucleoside di- and triphosphate were resolved. HPLC analyses of the nucleotide pool indicate that adenine derivatives were the most abundant components, but other nucleotides were present in significant amounts. The 1H and 13C resonance assignments of the majority of metabolites present in RIF-1 extracts have also been made. Of particular importance is the ability to observe lactate, the levels of which may provide a noninvasive measure of glycolysis in these cells in both the in vivo and in vitro states. In addition, the aminosulfonic acid, taurine, was found in high levels in the tumor extracts.  相似文献   
87.
D T C Fung  G Y F Ng 《Phytomedicine》2005,12(1-2):93-99
Herbal remedies have been reported to be effective in controlling inflammation for acute soft tissue injuries. There exist, however, no reports of their effects on collagen production and remodeling; thus mechanical strength studies of the tissues have not been reported. This study tested the effects of a herbal remedy on the strength of healing medial collateral ligaments (MCL) in rats. Sixteen rats receiving surgical transection to their right MCLs and eight receiving sham operation were tested. Eight of the MCL-injured animals were treated with an adhesive herbal plaster application to their right knees, while the other eight in the MCL injured group and the sham group were treated with plain adhesive plaster to their right knees. The MCLs were harvested and tested at either 3 or 6 weeks post-operation. The ultimate tensile strength (UTS) and stiffness normalized to the uninjured side of each animal of the herb and sham groups were significantly larger than those of the control at both 3 and 6 weeks (p = 0.001). No significant difference was found in stiffness between the herb and sham groups (p > 0.05). We concluded that the herbal remedy improves the UTS and stiffness of repairing MCLs at 3 and 6 weeks after injury.  相似文献   
88.
Three peptides corresponding to the C-terminal region of human growth hormone have been synthesized by the solid-phase method: HGH-(177--191), HGH-(178--191) and HGH-(179--191). The diabetogenic activities of these synthetic peptides are reported. The data indicate that extension of HGH-(179--191) at its NH2-terminus is required for in vivo activity. The reduced and S-carbamidomethylated form of HGH-(177--191) was also active, indicating that the disulphide bond is possibly not a prerequisite for biological activity.  相似文献   
89.
Tuberculosis (TB) disease can be caused by either recent transmission from infectious patients or reactivation of remote latent infection. Spatial dependency (correlation between nearby geographic areas) in tuberculosis incidence is a signature for chains of recent transmission with geographic diffusion. To understand the contribution of recent transmission in the TB endemic in Taiwan, where reactivation has been assumed to be the predominant mode of pathogenesis, we used spatial regression analysis to examine whether there was spatial dependency between the TB incidence in each township and in its neighbors. A total of 90,661 TB cases from 349 townships in 2003–2008 were included in this analysis. After adjusting for the effects of confounding socioeconomic variables, including the percentages of aboriginals and average household income, the results show that the spatial lag parameter remains positively significant (0.43, p<0.001), which indicates that the TB incidences of neighboring townships had an effect on the TB incidence in each township. Townships with substantial spatial spillover effects were mainly located in the northern, western and eastern parts of Taiwan. Spatial dependency implies that recent transmission plays a significant role in the pathogenesis of TB in Taiwan. Therefore, in addition to the current focus on improving the cure rate under directly observed therapy programs, more resource need to be allocated to active case finding in order to break the chain of transmission.  相似文献   
90.
Gallbladder carcinoma (GBC) is a vicious and invasive disease. The major challenge in the clinical treatment of GBC is the lack of a suitable prognosis method. Chemokine receptors such as CXCR3, CXCR4 and CXCR7 play vital roles in the process of tumour progression and metastasis. Their expression levels and distribution are proven to be indicative of the progression of GBC, but are hard to be decoded by conventional pathological methods, and therefore, not commonly used in the prognosis of GBC. In this study, we developed a computer‐aided image analysis method, which we used to quantitatively measure the expression levels of CXCR3, CXCR4 and CXCR7 in the nuclei and cytoplasm of glandular and interstitial cells from a cohort of 55 GBC patients. We found that CXCR3, CXCR4 and CXCR7 expressions are associated with the clinicopathological variables of GBC. Cytoplasmic CXCR3, nuclear CXCR7 and cytoplasmic CXCR7 were significant predictive factors of histology invasion, whereas cytoplasmic CXCR4 and nuclear CXCR4 were significantly correlated with T and N stage and were associated with the overall survival and disease‐free survival. These results suggest that the quantification and localisation of CXCR3, CXCR4 and CXCR7 expressions in different cell types should be considered using computer‐aided assessment to improve the accuracy of prognosis in GBC.  相似文献   
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