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151.
Yamamoto T Ichikawa M Takakura Y 《Biochemical and biophysical research communications》2008,365(2):340-343
Sialyltransferases are key enzymes for the biosynthesis of sialyl-glycoproteins and sialyl-lipids and the genes encoding sialyltransferases have been cloned from mammalian and bacterial source. In the mammalian sialyltransferase, existence of three conserved regions, named sialyl motifs, has been demonstrated. On the other hand, two short motifs, named D/E-D/E-G motif and HP motif, have been reported in the bacterial sialyltransferases very recently. From the results of multiple alignments among the sialyltransferases belonging to Glycosyltransferase family 80 and crystal structures of two reported sialyltransferases, it is clearly demonstrated that the third conserved-functional motif exists in the bacterial sialyltransferases that have been classified into Glycosyltransferase family 80 in this study. 相似文献
152.
A novel analogue of ganglioside GM3, in which sphingosine was replaced with a phytosphingosine moiety, was synthesized by intramolecular glycosylation as a key step. Glucose, a reducing terminal of the saccharide, and phytoceramide were first tethered by succinic acid and the derivative used for the subsequent glycosidic bond formation. The obtained glycosyl phytoceramide was further glycosylated with the sialyl galactose residue to afford a fully protected GM3 derivative, which was converted into the desired, final compound by using conventional deprotection procedures. 相似文献
153.
154.
Takakura T Ito T Yagi S Notsu Y Itakura T Nakamura T Inagaki K Esaki N Hoffman RM Takimoto A 《Applied microbiology and biotechnology》2006,70(2):183-192
l-Methionine γ-lyase is a pyridoxal 5′-phosphate-dependent enzyme which has tumor selective anticancer activity. An efficient
production process for the recombinant enzyme was constructed by using the overexpression plasmid in Escherichia coli, large-scale cultivation, and practical crystallization on an industrial scale. The plasmid was optimized with a promoter
and the region of the ribosome-binding site. Plasmid pMGLTrc03, which has a trc promoter and a spacing of 12 nucleotides between the Shine-Dalgarno sequence and the ATG translation initiation codon, was
selected as the most suitable plasmid. The transformants produced the enzyme, which intracellularly accumulated at 2.1 mg/ml
as an active form and accounted for 43% of the total proteins in the soluble fraction by simple batch fermentation using a
500-l fermentor. The crystals were directly obtained from crude enzyme with 87% yield by a crystallization in the presence
of 9.0% polyethylene glycol 6000, 3.6% ammonium sulfate, and 0.18 M sodium chloride using a 100-l crystallizer. After recrystallization,
the enzyme was purified by anion-exchange column chromatography to remove endotoxins and by gel filtration for polishing.
We prepared 600 g of purified enzyme with a low endotoxin content of sufficient quality for therapeutical use, with a 41%
overall yield in the purification process. 相似文献
155.
Immunosuppressed children and adults have a higher prevalence of oropharyngeal candidiasis. In this patient population, anti-fungal therapy of this condition is often ineffective, and new approaches to treatment are needed. The use of bovine lactoferrin is considered a promising option in treating oropharyngeal candidiasis. Here we review the results of in vitro and in vivo studies that have examined the antimicrobial characteristics of bovine lactoferrin as an adjunctive therapy for oropharyngeal candidiasis. 相似文献
156.
Excluding the central vacuole, chloroplasts constitute the largest compartment within the leaf cells of plants and contain approximately 80 percent of the total leaf nitrogen, mainly as proteins. Much of this nitrogen is allocated to the carbon-fixing enzyme in photosynthesis, Rubisco. During senescence, plants can mobilize nitrogen from chloroplasts in older leaves to other organs, such as developing seeds. Whereas bulk degradation of the cytosol and organelles in plants occurs by autophagy, the role of autophagy in the degradation of chloroplast proteins is still unclear. We have recently demonstrated that stroma-targeted green fluorescent protein (GFP), DsRed, and GFP-labeled Rubisco can be mobilized to the vacuole of living cells via Rubisco-containing bodies, in an ATG gene-dependent manner. Our results indicate the presence of a specific autophagic pathway for chloroplast stromal proteins, which does not cause chloroplast lysis. Here, we also discuss the involvement of stroma-filled tubules, stromules, which are important for the structural flexibility of the organelle, on the autophagic transfer of stromal proteins to the vacuole. 相似文献
157.
Eisuke Gotoh Aya Funada Mayumi Mohri Ryonfa Lee Kaoru Takakura 《Central European Journal of Biology》2008,3(2):121-133
To clarify the relationship between cell death and chromosomal aberrations following exposure to heavy-charged ion particles
beams, exponentially growing Human Salivary Gland Tumor cells (HSG cells) were irradiated with various kinds of high energy
heavy ions; 13 keV/μm carbon ions as a low-LET charged particle radiation source, 120 keV/μm carbon ions and 440 keV/μm iron
ions as high-LET charged particle radiation sources. X-rays (200 kVp) were used as a reference. Reproductive cell death was
evaluated by clonogenic assays, and the chromatid aberrations in G2/M phase and their repairing kinetics were analyzed by
the calyculin A induced premature chromosome condensation (PCC) method. High-LET heavy-ion beams introduced much more severe
and un-repairable chromatid breaks and isochromatid breaks in HSG cells than low-LET irradiation. In addition, the continuous
increase of exchange aberrations after irradiation occurred in the high-LET irradiated cells. The cell death, initial production
of isochromatid breaks and subsequent formation of chromosome exchange seemed to be depend similarly on LET with a maximum
RBE peak around 100–200 keV/μm of LET value. Conversely, un-rejoined isochromatid breaks or chromatid breaks/gaps seemed to
be less effective in reproductive cell death. These results suggest that the continuous yield of chromosome exchange aberrations
induced by high-LET ionizing particles is a possible reason for the high RBE for cell death following high-LET irradiation,
alongside other chromosomal aberrations additively or synergistically. 相似文献
158.
Kohki Yamamoto Toshifumi Suzuki Riyo Imamura Tetsuo Nagano Takayoshi Okabe Hiroyuki Miyachi 《Bioorganic & medicinal chemistry letters》2017,27(11):2567-2570
We present a practical synthesis of both enantiomers of 1,2,3,4-tetrahydroisoquinoline derivative IPPAM-1 (1), which is a positive allosteric modulator (PAM) of prostacyclin receptor (IP) and a candidate for treatment of pulmonary arterial hypertension without the side effects caused by IP agonists. Assay of cAMP production by CHO-K1 cells stably expressing human IP clearly demonstrated that the IPPAM activity resides exclusively on the R-form of 1. 相似文献
159.
Akira Takakura Kazuo Goto Toshio Itoh Kumiko Yoshimatsu Ikuo Takashima Jiro Arikawa 《Experimental Animals》2003,52(1):25-30
A recombinant nucleocapsid protein of Hantaan virus (HTN) 76-118 strain expressed in E. coli was applied as a serodiagnostic antigen in an enzyme-linked immunosorbent assay (rHTN-ELISA) for detection of hantavirus antibody in rat sera. The sensitivity and specificity of the rHTN-ELISA were compared with those of the indirect immunofluoresent assay (IFA) using virus-infected cells. The sensitivity of rHTN-ELISA was similar to that of the IFA both in experimentally SR-11 infected rat and naturally infected rat sera. Sera showing a low antibody titer in IFA and suspected to be negative by other methods were also found to be negative in rHTN-ELISA. These results indicate that rHTN-ELISA is effective as a screening method for serodiagnosis of hantaviruses, because of its high sensitivity, specificity, safety and suitability for processing large number of samples. 相似文献
160.