排序方式: 共有43条查询结果,搜索用时 15 毫秒
1.
B S Szwergold F Kappler T R Brown P Pfeffer S F Osman 《The Journal of biological chemistry》1989,264(16):9278-9282
The 31P NMR spectra of mammalian lenses show, in addition to previously identified compounds such as ATP, Pi, glycerophosphorylcholine, and alpha-glycerophosphate, an unusual phosphorylated metabolite resonating at 6.5 ppm. The concentration of this compound increases manyfold in the lenses of diabetic rats concomitant with activation of the aldose reductase pathway. We have purified this material and have identified it as D-sorbitol 3-phosphate. It appears likely that this unusual metabolite of sorbitol may reflect or be part of the metabolic aberration of diabetes in the lens. 相似文献
2.
Structural studies of a phosphocholine substituted beta-(1,3);(1,6) macrocyclic glucan from Bradyrhizobium japonicum USDA 110. 总被引:3,自引:0,他引:3
D B Rolin P E Pfeffer S F Osman B S Szwergold F Kappler A J Benesi 《Biochimica et biophysica acta》1992,1116(3):215-225
In our previous in vivo 31P study of intact nitrogen-fixing nodules (Rolin, D.B., Boswell, R.T., Sloger, C., Tu, S.I. and Pfeffer, P.E., 1989 Plant Physiol. 89, 1238-1246), we observed an unknown phosphodiester. The compound was also observed in the spectra of isolated bacteroids as well as extracts of the colonizing Bradyrhizobium japonicum USDA 110. In order to characterize the phosphodiester in the present study, we took advantage of the relatively hydrophobic nature of the material and purified it by elution from a C-18 silica reverse-phase chromatography column followed by final separation on an aminopropyl silica HPLC column. Structural characterization of this compound with a molecular weight of 2271 (FAB mass spectrometry), using 13C-1H and 31P-1H heteronuclear 2D COSY and double quantum 2D phase sensitive homonuclear 1H COSY NMR spectra, demonstrated that the molecule contained beta-(1,3); beta-(1,6); beta-(1,3,6) and beta-linked non-reducing terminal glucose units in the ratio of 5:6:1:1, respectively, as well as one C-6 substituted phosphocholine (PC) moiety associated with one group of (1,3) beta-glucose residues. Carbohydrate degradation analysis indicated that this material was a macrocyclic glucan, (absence of a reducing end group) with two separated units containing three consecutively linked beta-(1,3) glucose residues and 6 beta-(1,6) glucose residues. The sequences of beta-(1,3)-linked glucose units contained a single non-reducing, terminal, unsubstituted glucose linked at the C-6 position and a PC group attached primarily to an unsubstituted C-6 position of a beta-(1,3)-linked glucose. 相似文献
3.
BS Sabna Thankappan Bency Mahendran Ramasamy Muthusamy Gayathri Femil selta Daniel Raja Angayarkanni Jayaraman 《Probiotics and antimicrobial proteins》2021,13(4):993-1004
Probiotics and Antimicrobial Proteins - Gamma-aminobutyric acid (GABA) is a principal inhibitory neurotransmitter in the central nervous system and is produced by irreversible decarboxylation of... 相似文献
4.
Glyceraldehyde-3-phosphate dehydrogenase activity as an independent modifier of methylglyoxal levels in diabetes 总被引:4,自引:0,他引:4
Methylglyoxal (MG) may be an important cause of diabetic complications. Its primary source is dihydroxyacetone phosphate (DHAP) whose levels are partially controlled by glyceraldehyde-3-phosphate dehydrogenase (GAPDH). Using a human red blood cell (RBC) culture, we examined the effect of modifying GAPDH activity on MG production. With the inhibitor koningic acid (KA), we showed a linear, concentration-dependent GAPDH inhibition, with 5 microM KA leading to a 79% reduction of GAPDH activity and a sixfold increase in MG. Changes in redox state produced by elevated pH also resulted in a 2.4-fold increase in MG production at pH 7.5 and a 13.4-fold increase at pH 7.8. We found substantial inter-individual variation in DHAP and MG levels and an inverse relationship between GAPDH activity and MG production (R=0.57, P=0.005) in type 2 diabetes. A similar relationship between GAPDH activity and MG was observed in vivo in type 1 diabetes (R=0.29, P=0.0018).Widely varying rates of progression of diabetic complications are seen among individuals. We postulate that modification of GAPDH by environmental factors or genetic dysregulation and the resultant differences in MG production could at least partially account for this observation. 相似文献
5.
Anderson O. Lobo Erica F. Antunes Mariana BS Palma Cristina Pacheco‐Soares Vladimir J. Trava‐Airoldi Evaldo J. Corat 《Cell biology international》2010,34(4):393-398
Monolayer formation of SaOS‐2 (human osteoblast‐like cells) was observed on VACNT (vertically aligned multiwalled carbon nanotubes) scaffolds without purification or functionalization. The VACNT were produced by a microwave plasma chemical vapour deposition on titanium surfaces with nickel or iron as catalyst. Cell viability and morphology studies were evaluated by LDH (lactate dehydrogenase) release assay and SEM (scanning electron microscopy), respectively. The non‐toxicity and the flat spreading with monolayer formation of the SaOs‐2 on VACNT scaffolds surface indicate that they can be used for biomedical applications. 相似文献
6.
The immunophenotype of HT29 human colon cancer cells implanted into severe combined immunodeficient mice was assessed in primary
tumours and their metastases in the lungs using an indirect immunohistochemical method. After primary tumours were surgically
removed, the metastases were given time to develop, thus paralleling the clinical situation. While vimentin was negative in
both primary and secondary tumours, E-cadherin was present as membrane-bound labelling in the primary tumours only. Whereas
the markers p53, MIB1, PCNA and CEA were consistently positive in both primary and metastatic tumours, CD44 variant 6 and
CA125 were negative in metastases but positive in the primary tumours. There was a significant increase in the percentage
of cells labelled for p53 in the primary tumours compared with the metastases. For the proliferation markers, there was no
significant difference in labelling between primary tumours and metastases for MIB1. Of the cytokeratins examined, CK 20 gave
the strongest and most consistent reaction in both primary and secondary tumours. The results indicate that, for certain immunohistochemical
markers, results are the same in both primary tumours and metastases. Hence, in these cases, antigens that are expressed on
the primary tumour as well as on the metastases can serve as target molecules for immunologically based forms of treatment
of metastases.
This revised version was published online in November 2006 with corrections to the Cover Date. 相似文献
7.
8.
Comparisons of the molecular evolutionary process at rbcL and ndhF in the grass family (Poaceae) 总被引:2,自引:1,他引:1
We examine rate heterogeneity among evolutionary lineages of the grass
family at two plasmid loci, ndhF and rbcL, and we introduce a method to
determine whether patterns of rate heterogeneity are correlated between
loci. We show both that rates of synonymous evolution are heterogeneous
among grass lineages and that are heterogeneity is correlated between loci
at synonymous sites. At nonsynonymous sites, the pattern of rate
heterogeneity is not correlated between loci, primarily due to an aberrant
pattern of rate heterogeneity at nonsynonymous sites of rbcL. We compare
patterns of synonymous rate heterogeneity to predictors based on the
generation time effect and the speciation rate hypotheses. Although there
is some evidence for generation time effects, neither generation time
effects nor speciation rates appear to be sufficient to explain patterns of
rate heterogeneity in the grass plastid sequences.
相似文献
9.
10.
B S Szwergold F Kappler L H Cohen D Nanavati T R Brown 《Biochemical and biophysical research communications》1990,172(2):855-861
A novel metabolite of choline, phosphorylcholine methyl ester, has been identified in the eggs of S. purpuratus wherein it is present at approximately 1 mM concentration. To the best of our knowledge, this is the first instance of a phosphoryl-methyl-ester to be observed in nature. The compound appears to be species specific, since it has not been observed in other species such as L. pictus and P. depressus. In S. purpuratus its distribution is confined to the ovary, eggs and embryos, and is absent from young animals following metamorphosis. 相似文献