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131.
Katayama T Tanaka M Moriizumi J Nakamura T Brouchkov A Douglas TA Fukuda M Tomita F Asano K 《Applied and environmental microbiology》2007,73(7):2360-2363
Phylogenetic analysis of bacteria preserved within an ice wedge from the Fox permafrost tunnel was undertaken by cultivation and molecular techniques. The radiocarbon age of the ice wedge was determined. Our results suggest that the bacteria in the ice wedge adapted to the frozen conditions have survived for 25,000 years. 相似文献
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135.
Matsuki Y Ohmura-Hoshino M Goto E Aoki M Mito-Yoshida M Uematsu M Hasegawa T Koseki H Ohara O Nakayama M Toyooka K Matsuoka K Hotta H Yamamoto A Ishido S 《The EMBO journal》2007,26(3):846-854
The presence of post-translational regulation of MHC class II (MHC II) under physiological conditions has been demonstrated recently in dendritic cells (DCs) that potently function as antigen-presenting cells (APCs). Here, we report that MARCH-I, an E3 ubiquitin ligase, plays a pivotal role in the post-translational regulation of MHC II in B cells. MARCH-I expression was particularly high in B cells, and the forced expression of MARCH-I induced the ubiquitination of MHC II. In B cells from MARCH-I-deficient mice (MARCH-I KO), the half-life of surface MHC II was prolonged and the ubiquitinated form of MHC II completely disappeared. In addition, MARCH-I-deficient B cells highly expressed exogenous antigen-loaded MHC II on their surface and showed high ability to present exogenous antigens. These results suggest that the function of MHC II in B cells is regulated through ubiquitination by MARCH-I. 相似文献
136.
He PJ Hirata M Yamauchi N Hashimoto S Hattori MA 《Molecular and cellular biochemistry》2007,302(1-2):111-118
The circadian clock is responsible for the generation of circadian rhythms in hormonal secretion and metabolism. These peripheral
clocks could be reset by various cues in order to adapt to environmental variations. The ovary can be characterized as having
highly dynamic physiology regulated by gonadotropins. Here, we aimed to address the status of circadian clock in the ovary,
and to explore how gonadotropins could regulate clockwork in granulosa cells (GCs). To this end, we mainly utilized the immunohistochemistry,
RT-PCR, and real-time monitoring of gene expression methods. PER1 protein was constantly abundant across the daily cycle in
the GCs of immature ovaries. In contrast, PER1 protein level was obviously cyclic through the circadian cycle in the luteal
cells of pubertal ovaries. In addition, both FSH and LH induced Per1 expression in cultured immature and mature GCs, respectively. The promoter analysis revealed that the Per1 expression was mediated by the cAMP response element binding protein. In cultured transgenic GCs, both FSH and LH also induced
the circadian oscillation of Per2. However, the Per2 oscillation promoted by FSH quickly dampened within only one cycle, whereas the Per2 oscillation promoted by LH was persistently maintained. Collectively, these findings strongly suggest that both FSH and LH
play an important role in regulating circadian clock in the ovary; however, they might exert differential actions on the clockwork
in vivo due to each specific role within ovarian physiology. 相似文献
137.
Murabe M Yamauchi J Fujiwara Y Miyamoto Y Hiroyama M Sanbe A Tanoue A 《Biochemical and biophysical research communications》2007,356(3):739-744
Carbamazepine (CBZ) is one of the most commonly prescribed antiepileptic drugs (AEDs). However, a higher rate of congenital anomalies has been found in infants of mothers treated with CBZ during early pregnancy. Here, we characterize the effects of CBZ using a mouse ES cell differentiation system. The analysis of tissue-specific gene markers showed that CBZ induced early endodermal and mesodermal differentiation but inhibited differentiation of later stages. CBZ also induced ectodermal development, and there was evidence of neural differentiation as ES cells with an immature neuronal phenotype were observed. In contrast, valproic acid (VPA), another anticonvulsant drug, was previously shown to be able to induce ES cells to differentiate into neurons with a mature appearance. CBZ was less cytotoxic to ES cells than VPA. The in vitro ES cell assay system has the potential to provide a rapid and accurate approach for estimating the in vivo embryotoxicity of therapeutic drugs. 相似文献
138.
Unno H Ichimaida F Suzuki H Takahashi S Tanaka Y Saito A Nishino T Kusunoki M Nakayama T 《The Journal of biological chemistry》2007,282(21):15812-15822
The BAHD family is a class of acyl-CoA-dependent acyltransferases that are involved in plant secondary metabolism and show a diverse range of specificities for acyl acceptors. Anthocyanin acyltransferases make up an important class of the BAHD family and catalyze the acylation of anthocyanins that are responsible for most of the red-to-blue colors of flowers. Here, we describe crystallographic and mutational studies of three similar anthocyanin malonyltransferases from red chrysanthemum petals: anthocyanidin 3-O-glucoside-6'-O-malonyltransferase (Dm3MaT1), anthocyanidin 3-O-glucoside-3', 6'-O-dimalonyltransferase (Dm3MaT2), and a homolog (Dm3MaT3). Mutational analyses revealed that seven amino acid residues in the N- and C-terminal regions are important for the differential acyl-acceptor specificity between Dm3MaT1 and Dm3MaT2. Crystallographic studies of Dm3MaT3 provided the first structure of a BAHD member, complexed with acyl-CoA, showing the detailed interactions between the enzyme and acyl-CoA molecules. The structure, combined with the results of mutational analyses, allowed us to identify the acyl-acceptor binding site of anthocyanin malonyltransferases, which is structurally different from the corresponding portion of vinorine synthase, another BAHD member, thus permitting the diversity of the acyl-acceptor specificity of BAHD family to be understood. 相似文献
139.
Phylogenetic analysis based on 16S rRNA sequences with sequence data of some bacterial species of Pasteurellaceae related to rodents deposited in GenBank was performed along with biochemical characterization for the 20 strains of V-factor
dependent members of Pasteurellaceae derived from laboratory rats to obtain basic information and to investigate the taxonomic positions. The results of biochemical
tests for all strains were identical except for three tests, the ornithine decarboxylase test, and fermentation tests of D(+)
mannose and D(+) xylose. The biochemical properties of 8 of 20 strains that showed negative results for the fermentation test
of D(+) xylose agreed with those of Haemophilus parainfluenzae complex. By phylogenetic analysis, the strains were divided into two clusters that agreed with the results of the fermentation
test of xylose (group I: negative reaction for xylose, group II: positive reaction for xylose). The clusters were independent
of other bacterial species of Pasteurellaceae tested. The sequences of the strains in group I showed 99.7–99.8% similarity and the strains in group II showed 99.3–99.7%
similarity. None of the strains in group I had a close relation with Haemophilus parainfluenzae by phylogenetic analysis, although they showed the same biochemical properties. In conclusion, the strains had characteristic
biochemical properties and formed two independent groups within the “rodent cluster” of Pasteurellaceae that differed in the results of the fermentation test of xylose. Therefore, they seemed to be hitherto undescribed taxa in
Pasteurellaceae. 相似文献
140.
Miyaji T Kouzuma Y Yaguchi J Matsumoto R Kanost MR Kramer KJ Yonekura M 《Insect biochemistry and molecular biology》2007,37(9):960-968
A cysteine protease inhibitor (CPI) with an apparent molecular mass of 11.5kDa was purified from larval hemolymph of the tobacco hornworm (Manduca sexta) by gel filtration on Sephadex G-50 followed by hydrophobic and ion-exchange column chromatographies. The purified cysteine proteinase inhibitor, denoted as MsCPI, strongly inhibited the plant cysteine protease, papain, with a K(i) value of 5.5 x 10(-9)M. Nucleotide sequence analysis of a partial cDNA encoding MsCPI indicated that MsCPI consists of 105 amino acid residues in a sequence that is similar to sarcocystatin A from Sarcophaga peregrina. However, northern blotting and PCR analyses using the specific primers of MsCPI suggested that the mRNA encoding MsCPI had a size of more than 12 kilobases, which included at least six tandemly repeated MsCPI segments. MsCPI was expressed in Escherichia coli and the recombinant protein effectively inhibited cysteine proteases from plants as well as from animals such as cathepsins B (K(i), 6.8 nM), H (3.0 nM), and L (0.87 nM). There was no inhibition exhibited toward trypsin, chymotrypsin, subtilisin, pepsin or themolysin. 相似文献