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71.
Paknisa Sirimontree Natchanok Sritho Yuka Kanda Shoko Shinya Takayuki Ohnuma 《Bioscience, biotechnology, and biochemistry》2013,77(12):2014-2021
Enhancing the transglycosylation (TG) activity of glycoside hydrolases does not always result in the production of oligosaccharides with longer chains, because the TG products are often decomposed into shorter oligosaccharides. Here, we investigated the mutation strategies for obtaining chitooligosaccharides with longer chains by means of TG reaction catalyzed by family GH18 chitinase A from Vibrio harveyi (VhChiA). HPLC analysis of the TG products from incubation of chitooligosaccharide substrates, GlcNAcn, with several mutant VhChiAs suggested that mutant W570G (mutation of Trp570 to Gly) and mutant D392N (mutation of Asp392 to Asn) significantly enhanced TG activity, but the TG products were immediately hydrolyzed into shorter GlcNAcn. On the other hand, the TG products obtained from mutants D313A and D313N (mutations of Asp313 to Ala and Asn, respectively) were not further hydrolyzed, leading to the accumulation of oligosaccharides with longer chains. The data obtained from the mutant VhChiAs suggested that mutations of Asp313, the middle aspartic acid residue of the DxDxE catalytic motif, to Ala and Asn are most effective for obtaining chitooligosaccharides with longer chains. 相似文献
72.
Yoshihisa Tanaka Masanobu Kirita Yuko Abe Satoshi Miyata Motoyuki Tagashira Tomomasa Kanda 《Bioscience, biotechnology, and biochemistry》2013,77(7):1140-1146
Seven new O-methylated theaflavins (TFs) were synthesized by using O-methyltransferase from an edible mushroom. Using TFs and O-methylated TFs, metabolic stability in pooled human liver S9 fractions and inhibitory effect on H2O2-induced oxidative damage in human HepG2 cells were investigated. In O-methylation of theaflavin 3′-O-gallate (TF3′G), metabolic stability was potentiated by an increase in the number of introduced methyl groups. O-methylation of TF3,3′G did not affect metabolic stability, which was likely because of a remaining 3-O-galloyl group. The inhibitory effect on oxidative damage was assessed by measuring the viability of H2O2-damaged HepG2 cells treated with TFs and O-methylated TFs. TF3,3′G and O-methylated TFs increased cell viabilities significantly compared with DMSO, which was the compound vehicle (p?<?0.05), and improved to approximately 100%. Only TF3′G did not significantly increase cell viability. It was suggested that the inhibitory effect on H2O2-induced oxidative damage was potentiated by O-methylation or O-galloylation of TFs. 相似文献
73.
Youji Nakagawa Toru Hasebe Miyuki Ishiai Hideki Yamamura Yuzuru Iimura Masayuki Hayakawa 《Bioscience, biotechnology, and biochemistry》2013,77(4):714-717
We constructed a plasmid that expresses FLO11 encoding a cell surface glycoprotein of Saccharomyces cerevisiae under the control of a constitutive promoter. This plasmid conferred pellicle-forming ability on the non-pellicle-forming industrial strain of S. cerevisiae at the air–liquid interface of the glucose-containing liquid medium. The induced pellicle-forming cells exhibited tolerance to furfural, which is a key toxin in lignocellulosic hydrolysates, in ethanol production. 相似文献
74.
75.
Marcelo Magioli Katia Maria Paschoaletto Micchi de Barros Ferraz Eleonore Zulnara Freire Setz Alexandre Reis Percequillo Michelle Viviane de Sá Santos Rondon Vanessa Villanova Kuhnen Mariana Cristina da Silva Canhoto Karen Evelyn Almeida dos Santos Claudia Zukeran Kanda Gabriela de Lima Fregonezi Helena Alves do Prado Mitra Katherina Ferreira Milton Cezar Ribeiro Priscilla Marqui Schmidt Villela Luiz Lehmann Coutinho Márcia Gonçalves Rodrigues 《European Journal of Wildlife Research》2016,62(4):431-446
76.
77.
Atrophy or hypofunction of the salivary gland because of aging or disease leads to hyposalivation that affects patient quality of life by causing dry mouth, deterioration of mastication/deglutition, and poor oral hygiene status. Current therapy for atrophy or hypofunction of the salivary gland in clinical practice focuses on symptom relief using drugs and artificial saliva; therefore, there is still a need to develop new therapies. To investigate potential novel therapeutic targets, we induced the differentiation of salivary gland cells by co-culturing human adipose-derived stem cells isolated from buccal fat pads (hBFP-ASCs) with human salivary-gland-derived fibroblasts (hSG-fibros). We examined their potential for transplantation and tissue neogenesis. Following the culture of hBFP-ASCs and hSG-fibros, differentiated cells were transplanted into the submandibular glands of SCID mice, and their degree of differentiation in tissues was determined. We also examined their potential for functional tissue reconstitution using a three-dimensional (3D) culture system. Co-cultured cells expressed salivary-glandrelated markers and generated new tissues following transplantation in vivo. Moreover, cell reconstituted glandular structures in the 3D culture system. In conclusion, coculture of hSG-fibros with hBFP-ASCs led to successful differentiation into salivary gland cells that could be transplanted to generate new tissues. 相似文献
78.
Yoshikazu Furusawa Shinji Yamada Shunsuke Itai Takuro Nakamura Miyuki Yanaka Masato Sano Hiroyuki Harada Masato Fukui Mika K. Kaneko Yukinari Kato 《Biochemistry and Biophysics Reports》2019
Monoclonal antibodies (mAbs) against human, mouse, rat, rabbit, dog, cat, and bovine podoplanin (PDPN), a lymphatic endothelial cell marker, have been established in our previous studies. However, mAbs against horse PDPN (horPDPN), which are useful for immunohistochemical analysis, remain to be developed. In the present study, mice were immunized with horPDPN-overexpressing Chinese hamster ovary (CHO)-K1 cells (CHO/horPDPN), and hybridomas producing mAbs against horPDPN were screened using flow cytometry. One of the mAbs, PMab-219 (IgG2a, kappa), specifically detected CHO/horPDPN cells via flow cytometry and recognized horPDPN protein using Western blotting. Furthermore, PMab-219 strongly stained CHO/horPDPN via immunohistochemistry. These findings suggest that PMab-219 is useful for investigating the function of horPDPN. 相似文献
79.
Murayama K Shirouzu M Kawasaki Y Kato-Murayama M Hanawa-Suetsugu K Sakamoto A Katsura Y Suenaga A Toyama M Terada T Taiji M Akiyama T Yokoyama S 《The Journal of biological chemistry》2007,282(7):4238-4242
The Rac-specific guanine nucleotide exchange factor (GEF) Asef is activated by binding to the tumor suppressor adenomatous polyposis coli mutant, which is found in sporadic and familial colorectal tumors. This activated Asef is involved in the migration of colorectal tumor cells. The GEFs for Rho family GTPases contain the Dbl homology (DH) domain and the pleckstrin homology (PH) domain. When Asef is in the resting state, the GEF activity of the DH-PH module is intramolecularly inhibited by an unidentified mechanism. Asef has a Src homology 3 (SH3) domain in addition to the DH-PH module. In the present study, the three-dimensional structure of Asef was solved in its autoinhibited state. The crystal structure revealed that the SH3 domain binds intramolecularly to the DH domain, thus blocking the Rac-binding site. Furthermore, the RT-loop and the C-terminal region of the SH3 domain interact with the DH domain in a manner completely different from those for the canonical binding to a polyproline-peptide motif. These results demonstrate that the blocking of the Rac-binding site by the SH3 domain is essential for Asef autoinhibition. This may be a common mechanism in other proteins that possess an SH3 domain adjacent to a DH-PH module. 相似文献
80.
Naohisa Kanda Mutsuo Goto Hidehiro Kato Megan V. McPhee Luis A. Pastene 《Conservation Genetics》2007,8(4):853-864
Bryde’s whales (Balaenoptera brydei) differ from other typical baleen whale species because they are restricted to tropical and warm temperate waters in major
oceans, and frequent trans-equatorial movement has been suggested for the species. We tested this hypothesis by analyzing
genetic variation at 17 microsatellite loci (N = 508) and 299 bp of mitochondrial DNA (mtDNA) control region sequences (N = 472) in individuals obtained from the western North Pacific, South Pacific, and eastern Indian Ocean. Combined use of microsatellite
and mtDNA markers allowed us to distinguish between contemporary gene flow and ancestral polymorphism and to describe sex-specific
philopatry. A high level of genetic diversity was found within the samples. Both nuclear and mtDNA markers displayed similar
population structure, indicating a lack of sex-specific philopatry. Spatial structuring was detected using both frequency-based
population parameters and individual-based Bayesian approaches. Whales in the samples from different oceanic regions came
from genetically distinct populations with evidence of limited gene flow. We observed low mtDNA sequence divergence among
populations and a lack of concordance between geographic and phylogenetic position of mtDNA haplotypes, suggesting recent
separation of populations rather than frequent trans-equatorial and inter-oceanic movement. We conclude that current gene
flow between Bryde’s whale populations is low and that effective management actions should treat them as separate entities
to ensure continued existence of the species. 相似文献