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991.
992.
Human colonic adenocarcinoma Caco-2 cells differentiate into enterocytes by induction with sodium butyrate after confluence. Our previous studies have shown that there are high levels of H type 1 blood group antigen and core 2 structure present in O-glycans of the glycoproteins from these differentiated cells and these O-glycans appear to be indispensable for the process of differentiation of the cells (J. Amano and M. Oshima, 1999, J. Biol. Chem. 274, 21209-21216). Here, we have determined the glycosyltransferase activities using lectin-affinity HPLC because the method enabled easy separation and identification of mixtures of isomeric oligosaccharide structures due to the high resolution and reproducibility. The activities of beta 3-galactosyltransferase, alpha 2-fucosyltransferase, which are responsible for H type 1 antigen biosynthesis, and core 2 beta 6-N-acetylglucosaminyltransferase in differentiated Caco-2 cells were higher than those in undifferentiated cells. These results demonstrate that an increase in specific glycosyltransferase activities brought on a change of the O-glycan structures during differentiation. 相似文献
993.
994.
We observed that α-amylase (Taka-amylase A; TAA) activity in the culture broth disappeared in the later stage of submerged
cultivation of Aspergillus oryzae. This disappearance was caused by adsorption of TAA onto the cell wall of A. oryzae and not due to protein degradation by extracellular proteolytic enzymes. To determine the cell wall component(s) that allows
TAA adsorption efficiently, the cell wall was fractionated by stepwise alkali treatment and enzymatic digestion. Consequently,
alkali-insoluble cell wall fractions exhibited high levels of TAA adsorption. In addition, this adsorption capacity was significantly
enhanced by treatment of the alkali-insoluble fraction with β-glucanase, which resulted in the concomitant increase in the
amount of chitin in the resulting fraction. In contrast, the adsorption capacity was diminished by treating the cell wall
fraction with chitinase. These results suggest that the major component that allows TAA adsorption is chitin. However, both
the mycelium and the cell wall demonstrated the inability to allow TAA adsorption in the early stage of cultivation, despite
chitin content in the cell wall being identical in both early and late stages of cultivation. These results suggest the existence
of unidentified factor(s) that could prevent the adsorption of TAA onto the cell wall. Such factor(s) is most likely removed
or diminished from the cell wall following longer cultivation periods. 相似文献
995.
Alpha-fetoprotein (AFP) is a fetal glycoprotein that is known as a biomarker for monitoring pregnancy in many mammalian species. However, characterization of AFP has not yet been undertaken in any cetacean species. Here, we purified AFP from the serum of fetal striped dolphin by chemical precipitation followed by a combination of immunoadsorbent column chromatography and gel filtration. The molecular masses of native and denatured dolphin AFP were estimated to be ~78,000 Da by gel filtration and ~68,000 Da by SDS-PAGE, respectively, representing typical masses reported for mammalian AFPs. In fetal serum, only the AFP band (~68,000 Da) appeared to be immunoreactive to an antiserum against purified dolphin AFP, indicating sufficient specificity for the development of an AFP immunoassay. Full-length cDNA encoding for the dolphin AFP was cloned from fetal liver and revealed an open reading frame comprising 610 amino acid residues, which included a putative signal peptide of 18 amino acid residues. This was followed by a sequence identical to the N-terminus of purified AFP. The deduced amino acid sequence of dolphin AFP showed more than 80% identity to those of other mammalian AFPs. To our knowledge, the present report represents the first identification and characterization of AFP from any cetacean species. 相似文献
996.
McCord JL Tsuchimochi H Yamauchi K Leal A Kaufman MP 《Journal of applied physiology (Bethesda, Md. : 1985)》2011,111(4):971-979
In decerebrate rats, we reported previously that the exercise pressor reflex arising from a limb whose femoral artery was occluded for 72 h before the experiment was significantly higher than the exercise pressor reflex arising from a contralateral freely perfused limb. These findings prompted us to examine whether reactive oxygen species contributed to the augmented pressor reflex in rats with femoral artery occlusion. We found that the pressor reflex arising from the limb whose femoral artery was occluded for 72 h before the experiment (31 ± 5 mmHg) was attenuated by tempol (10 mg), a superoxide dismutase (SOD) mimetic (18 ± 5 mmHg, n = 9, P < 0.05), that was injected into the arterial supply of the hindlimb. In contrast, the pressor reflex arising from a freely perfused hindlimb (20 ± 3 mmHg) was not attenuated by tempol (17 ± 4 mmHg, n = 10, P = 0.49). Nevertheless, we found no difference in the increase in 8-isoprostaglandin F(2α) levels, an index of reactive oxygen species, in response to contraction between freely perfused (3.76 ± 0.82 pg/ml, n = 19) and 72-h occluded (3.51 ± 0.92 pg/ml, n = 22, P = 0.90) hindlimbs. Moreover, tempol did not reduce the 8-isoprostaglandin F(2α) levels during contraction in either group (P > 0.30). A second SOD mimetic, tiron (200 mg/kg), had no effect on the exercise pressor reflex in either the rats with freely perfused hindlimbs or in those with occluded femoral arteries. These findings suggest that tempol attenuated the exercise pressor reflex in the femoral artery-occluded hindlimb by a mechanism that was independent of its ability to scavenge reactive oxygen species. 相似文献
997.
Morita H Abo H Okamoto A Maeda H Yamagata Y Kusumoto K Amano H Ishida H Takeuchi M 《Bioscience, biotechnology, and biochemistry》2011,75(4):662-668
Gene AO090103000153 is unique to Aspergillus oryzae RIB40 and A. flavus NRRL3357, and is speculated to encode a serine-type carboxypeptidase. In this study, we purified and characterized a heterologously expressed gene product of AO090103000153. 5'-Rapid amplification of cDNA ends indicated that the translation start site of the gene is located 1,586 bp downstream of the translation start site predicted by the genome sequencing project. The gene, starting from the revised translation start codon, termed ocpC, was transcribed constantly in A. oryzae RIB40. Purified recombinant OcpC exhibited the enzymatic properties of a serine-type carboxypeptidase. This protease was stable at temperatures below 45°C and a low pH, and had broad substrate specificity for N-acylpeptides, but it exhibited significantly lower specific activity and a lower k(cat) value for substrates than previously reported serine-type carboxypeptidases from A. oryzae. 相似文献
998.
Harada K Amano K Akimoto S Yamamoto K Yamamoto Y Yanagihara K Kohno S Kishida N Takahashi T 《The new microbiologica》2011,34(4):409-412
We characterized the serological and pathogenic properties of two Erysipelothrix rhusiopathiae isolates from human cases of infective endocarditis in Japan. One isolate was recovered from a fisherman, and was identified as serovar 3, which is known to be prevalent among fish isolates. This strain exhibited high virulence in mice but was avirulent in swine. Another was untypable, and avirulent in both mice and swine. Our results suggest that various serological and athogenical types of E. rhusiopathiae can induce human endocarditis. This is the first report to characterize the pathogenicity of E. rhusiopathiae isolates from human endocarditis. 相似文献
999.
RecA is a highly conserved bacterial protein that plays crucial roles in many cellular processes and hence is a potential target in the chemotherapy of bacterial infections. An understanding of the functional similarity between RecA proteins from different bacterial species should yield further insights into the biochemistry of RecA protein, along with the potential for new approaches to facilitate the improvement of RecA-targeted drugs. In this technical note, the authors present an in silico method based on tri-oligonucleotide usage correlations (TOUC) to predict the functional similarity between two RecA orthologs. The TOUC values analyzed in this study are in good agreement with the available experimental results. This method should prove useful in guiding future experimental efforts aimed at furthering our understanding of the biochemistry of RecA proteins and subsequent development of new drugs that modulate RecA biological activities in bacteria. 相似文献
1000.
Yamamoto SP Okawa K Nakano T Sano K Ogawa K Masuda T Morikawa Y Koyanagi Y Suzuki Y 《Microbes and infection / Institut Pasteur》2011,13(4):339-349
Integration, an indispensable step for retrovirus replication, is executed by integrase (IN), which is expressed as a part of a Gag-Pol precursor. Although mechanistic detail of the IN-catalyzed integration reaction is well defined, numerous evidence have demonstrated that IN is involved in multiple steps of retrovirus replication other than integration. In this study, Huwe1, a HECT-type E3 ubiquitin ligase, was identified as a new cellular interactor of human immunodeficiency virus type 1 (HIV-1) IN. The interaction was mediated through the catalytic core domain of IN and a wide-range region of Huwe1. Interestingly, although depletion of Huwe1 in target cells did not affect the early phase of HIV-1 infection in a human T cell line, we found that infectivity of HIV-1 released from the Huwe1 knockdown cells was significantly augmented more than that of virus produced from control cells. The increase in infectivity occurred in proviral DNA synthesis. Further analysis revealed that Huwe1 interacted with HIV-1 Gag-Pol precursor protein through an IN domain. Our results suggest that Huwe1 in HIV-1 producer cells has a negative impact on early post-entry events during the next round of virus infection via association with an IN region of Gag-Pol. 相似文献