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241.
Noc2, a putative Rab effector, contributes to secretory-granule exocytosis in neuroendocrine and exocrine cells. Here, using two-photon excitation live-cell imaging, we investigated its role in Ca(2+)-dependent zymogen granule (ZG) exocytosis in pancreatic acinar cells from wild-type (WT) and Noc2-knockout (KO) mice. Imaging of a KO acinar cell revealed an expanded granular area, indicating ZG accumulation. In our spatiotemporal analysis of the ZG exocytosis induced by agonist (cholecystokinin or acetylcholine) stimulation, the location and rate of progress of ZG exocytosis did not differ significantly between the two strains. ZG exocytosis from KO acinar cells was seldom observed at physiological concentrations of agonists, but was normal (vs. WT) at high concentrations. Flash photolysis of a caged calcium compound confirmed the integrity of the fusion step of ZG exocytosis in KO acinar cells. The decreased ZG exocytosis present at physiological concentrations of agonists raised the possibility of impaired elicitation of calcium spikes. When calcium spikes were evoked in KO acinar cells by a high agonist concentration: (a) they always started at the apical portion and traveled to the basal portion, and (b) calcium oscillations over the 10 μM level were observed, as in WT acinar cells. At physiological concentrations of agonists, however, sufficient calcium spikes were not observed, suggesting an impaired [Ca(2+)](i)-increase mechanism in KO acinar cells. We propose that in pancreatic acinar cells, Noc2 is not indispensable for the membrane fusion of ZG per se, but instead performs a novel function favoring agonist-induced physiological [Ca(2+)](i) increases. 相似文献
242.
243.
Ikeda R Iwashita K Sumizawa T Beppu S Tabata S Tajitsu Y Shimamoto Y Yoshida K Furukawa T Che XF Yamaguchi T Ushiyama M Miyawaki A Takeda Y Yamamoto M Zhao HY Shibayama Y Yamada K Akiyama S 《Experimental cell research》2008,314(16):3017-3026
The major vault protein (MVP) is the major constituent of the vault particle, the largest ribonuclear protein complex described to date and is identical to lung resistance-related protein (LRP). Although MVP is also expressed in several normal tissues, little is known about its physiological role. MVP played a protective role against some xenobiotics and other stresses. We thus investigated the effect of osmotic stress on MVP expression by treating human colon cancer SW620 cells with sucrose or NaCl. The expression level of both MVP protein and MVP mRNA was increased by the osmostress. Sucrose or sodium chloride could also enhance MVP promoter activity. Inhibition of p38 MAPK in SW620 cells by SB203580 inhibited the expression of MVP under hyperosmotic stress. These findings suggested that osmotic stress up-regulated the MVP expression through p38 MAPK pathway. Down-regulation of MVP expression by MVP interfering RNA (RNAi) in SW620 cells increased the sensitivity of the cells to hyperosmotic stress and enhanced apoptosis. Furthermore, MVP RNAi prevented the osmotic stress-induced, time-dependent increase in phosphorylated Akt. These findings suggest that the PI3K/Akt pathway might be implicated in the cytoprotective effect of MVP.Our data demonstrate that exposure of cells to hyperosmotic stress induces MVP that might play an important role in the protection of the cells from the adverse effects of osmotic stress. 相似文献
244.
Unprecedented intraspecific diversity of the MHC class I region of a teleost medaka, Oryzias latipes
Tsukamoto K Hayashi S Matsuo MY Nonaka MI Kondo M Shima A Asakawa S Shimizu N Nonaka M 《Immunogenetics》2005,57(6):420-431
The major histocompatibility complex (MHC) is present at a single chromosomal locus of all jawed vertebrate analyzed so far,
from sharks to mammals, except for teleosts whose orthologs of the mammalian MHC-encoded genes are dispersed at several chromosomal
loci. Even in teleosts, several class IA genes and those genes directly involved in class I antigen presentation preserve
their linkage, defining the teleost MHC class I region. We determined the complete nucleotide sequence of the MHC class I
region of the inbred HNI strain of medaka, Oryzias latipes (northern Japan population-derived), from four overlapping bacterial artificial chromosome (BAC) clones spanning 540,982 bp,
and compared it with the published sequence of the corresponding region of the inbred Hd-rR strain of medaka (425,935 bp,
southern Japan population-derived) as the first extensive study of intraspecies polymorphisms of the ectotherm MHC regions.
A segment of about 100 kb in the middle of the compared sequences encompassing two class Ia genes and two immunoproteasome
subunit genes, PSMB8 and PSMB10, was so divergent between these two inbred strains that a reliable sequence alignment could not be made. The rest of the
compared region (about 320 kb) showed a fair correspondence, and an approximately 96% nucleotide identity was observed upon
gap-free segmental alignment. These results indicate that the medaka MHC class I region contains an ∼100-kb polymorphic core,
which is most probably evolving adaptively by accumulation of point mutations and extensive genetic rearrangements such as
insertions, deletions and duplications.
The nucleotide sequence data of HNI MHC class I region reported in this paper have been submitted to the DDBJ/EMBL/GenBank
and were assigned the accession number AB183488. 相似文献
245.
246.
Atsushi Sato Nobuo Ida Mari Ishikawa Kazuhiro Tanahashi Haruji Nakamura Yukihiko Sho Terukatsu Arima Tetsunosuke Kunitomo 《Microbiology and immunology》1993,37(4):295-304
An enzyme-linked immunosorbent assay (ELISA) was developed for the detection of anti-HCV antibody. We assayed for antibodies against either oligopeptide (S29-1) deduced from the nucleocapsid gene or the product of nonstructural region (NS3) synthesized in a recombinant Escherichia coli (S4). To reduce false-positive results induced by non-specific binding of antibodies with a carrier protein and to increase the sensitivity of an immunoassay, non-fused S4 peptide was prepared by the recombinant DNA technique and site-specific proteolysis (by factor Xa). In 71 non-A, non-B hepatitis patients with chronic liver disease, 70 (98.5%) were positive by S29-1/S4 ELISA as well as by a second-generation test (Abbott II). On the other hand, of 40 serum samples from blood donors, in which anti-N14 (core) and C100-3 antibodies were not detected but hepatitis C virus (HCV) RNA was detectable by polymerase chain reaction (PCR), 24 (60%) were positive by S29-1/S4 ELISA, whereas only 18 (45%) were diagnosed by Abbott II. In addition, based on results in a small group of 92 blood donors, detection of anti-S29-1/S4 antibody correlated well with HCV viremia as confirmed by PCR. These results indicated that the preparation of non-fused protein (S4) by recombinant DNA technique and a combination of S29-1 and S4 as immobilized antigens in an ELISA provide a sensitive and specific diagnosis for HCV infection with good correlation with the presence of viral RNA as confirmed by PCR. 相似文献
247.
Comparison of the biological properties of purified natural and recombinant human interleukin-2 总被引:6,自引:0,他引:6
K Naruo S Hinuma K Kato M Koyama H Tada O Shiho K Tsukamoto 《Biochemical and biophysical research communications》1985,128(1):257-264
We compared the biological properties of the purified recombinant human IL-2 derived from E. coli with those of purified natural IL-2. Both had almost the same specific in vitro activities on a weight basis to support long-term proliferation of IL-2 dependent human peripheral blood lymphocytes, a mouse killer T cell line, and a mouse natural killer cell line; induce killer cells in normal mouse spleen cells; and induce antibody forming cells in nude mouse spleen cells. No differences in these biological activities were found between two forms of natural IL-2 that were separable by reverse phase high performance liquid chromatography. 相似文献
248.
Fumi Ota Tetsuya Hirayama Yasuhiko Kizuka Yoshiki Yamaguchi Reiko Fujinawa Masahiro Nagata Hendra S. Ismanto Bernd Lepenies Jonas Aretz Christoph Rademacher Peter H. Seeberger Takashi Angata Shinobu Kitazume Keiichi Yoshida Tomoko Betsuyaku Kozui Kida Sho Yamasaki Naoyuki Taniguchi 《Biochimica et Biophysica Acta (BBA)/General Subjects》2018,1862(7):1592-1601
Background
Langerin, a C-type lectin receptor (CLR) expressed in a subset of dendritic cells (DCs), binds to glycan ligands for pathogen capture and clearance. Previous studies revealed that langerin has an unusual binding affinity toward 6-sulfated galactose (Gal), a structure primarily found in keratan sulfate (KS). However, details and biological outcomes of this interaction have not been characterized. Based on a recent discovery that the disaccharide L4, a KS component that contains 6-sulfo-Gal, exhibits anti-inflammatory activity in mouse lung, we hypothesized that L4-related compounds are useful tools for characterizing the langerin-ligand interactions and their therapeutic application.Methods
We performed binding analysis between purified long and short forms of langerin and a series of KS disaccharide components. We also chemically synthesized oligomeric derivatives of L4 to develop a new high-affinity ligand of langerin.Results
We show that the binding critically requires the 6-sulfation of Gal and that the long form of langerin displays higher affinity than the short form. The synthesized trimeric (also designated as triangle or Tri) and polymeric (pendant) L4 derivatives displayed over 1000-fold higher affinity toward langerin than monomeric L4. The pendant L4, but not the L4 monomer, was found to effectively transduce langerin signaling in a model cell system.Conclusions
L4 is a specific ligand for langerin. Oligomerization of L4 unit increased the affinity toward langerin.General significance
These results suggest that oligomeric L4 derivatives will be useful for clarifying the langerin functions and for the development of new glycan-based anti-inflammatory drugs. 相似文献249.
Ayako Katsuki Hikaru Kato Yurika Tahara Makoto Hashimoto Isao Fujii Sachiko Tsukamoto 《Bioorganic & medicinal chemistry》2018,26(8):1869-1874
The fungus Aspergillus japonicus MF275 produces himeic acid A (1), containing a 4-pyrone ring, along with its congeners, himeic acids B (2) and C (3). During culture, 1 was gradually converted to 3, the corresponding 4-pyridone derivative. A study of the relationship between the culture pH and the fungal metabolites showed that a decrease from pH 6.5 to pH 2 is essential for production of 1, while a subsequent increase to pH 5 is necessary for production of 3. In addition, we revealed that 1 was non-enzymatically converted to 3 by the incorporation of an ammonium nitrogen atom in a pH 5 buffer, and that 1 was converted to 2 at a conversion ratio of 50% during incubation in MeOH for five days. 相似文献
250.
Takumi Okubo Daiki Hayashi Takayuki Yaguchi Yudai Fujita Motoharu Sakaue Takehito Suzuki Atsushi Tsukamoto Ohoshi Murayama Jonathan Lynch Yoko Miyazaki Kazuaki Tanaka Tatsuya Takizawa 《Experimental Animals》2016,65(1):45-51
Valproic acid (VPA) is a widely used antiepileptic drug, which has recently been reported
to modulate the neuronal differentiation of adipose tissue-derived stem cells (ASCs) in
humans and dogs. However, controversy exists as to whether VPA really acts as an inducer
of neuronal differentiation of ASCs. The present study aimed to elucidate the effect of
VPA in neuronal differentiation of rat ASCs. One or three days of pretreatment with VPA (2
mM) followed by neuronal induction enhanced the ratio of immature neuron marker
βIII-tubulin-positive cells in a time-dependent manner, where the majority of cells also
had a positive signal for neurofilament medium polypeptide (NEFM), a mature neuron marker.
RT-PCR analysis revealed increases in the mRNA expression of microtubule-associated
protein 2 (MAP2) and NEFM mature neuron markers, even
without neuronal induction. Three-days pretreatment of VPA increased acetylation of
histone H3 of ASCs as revealed by immunofluorescence staining. Chromatin
immunoprecipitation assay also showed that the status of histone acetylation at H3K9
correlated with the gene expression of TUBB3 in ASCs by VPA. These
results indicate that VPA significantly promotes the differentiation of rat ASCs into
neuron-like cells through acetylation of histone H3, which suggests that VPA may serve as
a useful tool for producing transplantable cells for future applications in clinical
treatments. 相似文献