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81.
82.
Nobuyuki Kawasaki Kazuhiro Komatsu Ayato Kohzu Noriko Tomioka Ryuichiro Shinohara Takayuki Satou Fumiko Nara Watanabe Yuya Tada Koji Hamasaki M. R. M. Kushairi Akio Imai 《Applied and environmental microbiology》2013,79(23):7160-7168
Incubation experiments using filtered waters from Lake Kasumigaura were conducted to examine bacterial contribution to a dissolved organic carbon (DOC) pool. Bacterial abundance, bacterial production, concentrations of DOC, total dissolved amino acids (TDAA), and total dissolved neutral sugars (TDNS) were monitored during the experiments. Bacterial production during the first few days was very high (20 to 35 μg C liter−1 day−1), accounting for 40 to 70% of primary production. The total bacterial production accounted for 34 to 55% of the DOC loss during the experiment, indicating high bacterial activities in Lake Kasumigaura. The DOC degradation was only 12 to 15%, whereas the degradation of TDAA and TDNS ranged from 30 to 50%, suggesting the preferential usage of TDAA and TDNS. The contribution of bacterially derived carbon to a DOC pool in Lake Kasumigaura was estimated using d-amino acids as bacterial biomarkers and accounted for 30 to 50% of the lake DOC. These values were much higher than those estimated for the open ocean (20 to 30%). The ratio of bacterially derived carbon to bulk carbon increased slightly with time, suggesting that the bacterially derived carbon is more resistant to microbial degradation than bulk carbon. This is the first study to estimate the bacterial contribution to a DOC pool in freshwater environments. These results indicate that bacteria play even more important roles in carbon cycles in freshwater environments than in open oceans and also suggests that recent increases in recalcitrant DOC in various lakes could be attributed to bacterially derived carbon. The potential differences in bacterial contributions to dissolved organic matter (DOM) between freshwater and marine environments are discussed. 相似文献
83.
Tetsurou Muroi Takaaki Kokuzawa Yoshihiko Kihara Ryuichi Kobayashi Nobutaka Hirano Hideo Takahashi Mitsuru Haruki 《Applied microbiology and biotechnology》2013,97(9):4039-4048
Serine-type phage integrases catalyze unidirectional site-specific recombination between the attachment sites, attP and attB, in the phage and host bacterial genomes, respectively; these integrases and DNA target sites function efficiently when transferred into heterologous cells. We previously developed an in vivo site-specific genomic integration system based on actinophage TG1 integrase that introduces ~2-kbp DNA into an att site inserted into a heterologous Escherichia coli genome. Here, we analyzed the TG1 integrase-mediated integrations of att site-containing ~10-kbp DNA into the corresponding att site pre-inserted into various genomic locations; moreover, we developed a system that introduces ~10-kbp DNA into the genome with an efficiency of ~104 transformants/μg DNA. Integrations of attB-containing DNA into an attP-containing genome were more efficient than integrations of attP-containing DNA into an attB-containing genome, and integrations targeting attP inserted near the replication origin, oriC, and the E. coli “centromere” analogue, migS, were more efficient than those targeting attP within other regions of the genome. Because the genomic region proximal to the oriC and migS sites is located at the extreme poles of the cell during chromosomal segregation, the oriC–migS region may be more exposed to the cytosol than are other regions of the E. coli chromosome. Thus, accessibility of pre-inserted attP to attB-containing incoming DNA may be crucial for the integration efficiency by serine-type integrases in heterologous cells. These results may be beneficial to the development of serine-type integrases-based genomic integration systems for various bacterial species. 相似文献
84.
Takahiro Inoue Kyosuke Takao Takashi Yoshida Kei Wada Takashi Daifuku Yasuko Yoneda Keiichi Fukuyama Yoshihiko Sako 《Biochemical and biophysical research communications》2013
A unique [Ni–Fe–S] cluster (C-cluster) constitutes the active center of Ni-containing carbon monoxide dehydrogenases (CODHs). His261, which coordinates one of the Fe atoms with Cys295, is suggested to be the only residue required for Ni coordination in the C-cluster. To evaluate the role of Cys295, we constructed CODH-II variants. Ala substitution for the Cys295 substitution resulted in the decrease of Ni content and didn’t result in major change of Fe content. In addition, the substitution had no effect on the ability to assemble a full complement of [Fe–S] clusters. This strongly suggests Cys295 indirectly and His261 together affect Ni-coordination in the C-cluster. 相似文献
85.
Akiharu Kubo Aiko Shiohama Takashi Sasaki Kazuhiko Nakabayashi Hiroshi Kawasaki Toru Atsugi Showbu Sato Atsushi Shimizu Shuji Mikami Hideaki Tanizaki Masaki Uchiyama Tatsuo Maeda Taisuke Ito Jun-ichi Sakabe Toshio Heike Torayuki Okuyama Rika Kosaki Kenjiro Kosaki Jun Kudoh Kenichiro Hata Akihiro Umezawa Yoshiki Tokura Akira Ishiko Hironori Niizeki Kenji Kabashima Yoshihiko Mitsuhashi Masayuki Amagai 《American journal of human genetics》2013,93(5):945-956
“Nagashima-type” palmoplantar keratosis (NPPK) is an autosomal recessive nonsyndromic diffuse palmoplantar keratosis characterized by well-demarcated diffuse hyperkeratosis with redness, expanding on to the dorsal surfaces of the palms and feet and the Achilles tendon area. Hyperkeratosis in NPPK is mild and nonprogressive, differentiating NPPK clinically from Mal de Meleda. We performed whole-exome and/or Sanger sequencing analyses of 13 unrelated NPPK individuals and identified biallelic putative loss-of-function mutations in SERPINB7, which encodes a cytoplasmic member of the serine protease inhibitor superfamily. We identified a major causative mutation of c.796C>T (p.Arg266∗) as a founder mutation in Japanese and Chinese populations. SERPINB7 was specifically present in the cytoplasm of the stratum granulosum and the stratum corneum (SC) of the epidermis. All of the identified mutants are predicted to cause premature termination upstream of the reactive site, which inhibits the proteases, suggesting a complete loss of the protease inhibitory activity of SERPINB7 in NPPK skin. On exposure of NPPK lesional skin to water, we observed a whitish spongy change in the SC, suggesting enhanced water permeation into the SC due to overactivation of proteases and a resultant loss of integrity of the SC structure. These findings provide an important framework for developing pathogenesis-based therapies for NPPK. 相似文献
86.
Chisato Kusunoki Liu Yang Takeshi Yoshizaki Fumiyuki Nakagawa Atsushi Ishikado Motoyuki Kondo Katsutaro Morino Osamu Sekine Satoshi Ugi Yoshihiko Nishio Atsunori Kashiwagi Hiroshi Maegawa 《Biochemical and biophysical research communications》2013,430(1):225-230
Oxidative stress is produced in adipose tissue of obese subjects and has been associated with obesity-related disorders. Recent studies have shown that omega-3 polyunsaturated fatty acid (ω3-PUFA) has beneficial effects in preventing atherosclerotic diseases and insulin resistance in adipose tissue. However, the role of ω3-PUFA on adipocytes has not been elucidated. In this study, 3T3-L1 adipocytes were treated with ω3-PUFA and its metabolites, eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA), or 4-hydroxy hexenal (4-HHE). ω3-PUFA and its metabolites dose-dependently increased mRNA and protein levels of the anti-oxidative enzyme, heme oxygenase-1 (HO-1); whereas no changes in the well-known anti-oxidant molecules, superoxide dismutase, catalase, and glutathione peroxidase, were observed. Knockdown of nuclear factor erythroid 2-related factor 2 (Nrf-2) significantly reduced EPA, DHA or 4-HHE-induced HO-1 mRNA and protein expression. Also, pretreatment with ω3-PUFA prevented H2O2-induced cytotoxicity in a HO-1 dependent manner. In conclusion, treatment with EPA and DHA induced HO-1 through the activation of Nrf-2 and prevented oxidative stress in 3T3-L1 adipocytes. This anti-oxidant defense may be of high therapeutic value for clinical conditions associated with systemic oxidative stress. 相似文献
87.
Masato Ohtani Toshiaki Kondo Naoki Tani Saneyoshi Ueno Leong S. Lee Kevin K. S. Ng Norwati Muhammad Reiner Finkeldey Mohamad Na'iem Sapto Indrioko Koichi Kamiya Ko Harada Bibian Diway Eyen Khoo Kensuke Kawamura Yoshihiko Tsumura 《Molecular ecology》2013,22(8):2264-2279
Tropical rainforests in South‐East Asia have been affected by climatic fluctuations during past glacial eras. To examine how the accompanying changes in land areas and temperature have affected the genetic properties of rainforest trees in the region, we investigated the phylogeographic patterns of a widespread dipterocarp species, Shorea leprosula. Two types of DNA markers were used: expressed sequence tag‐based simple sequence repeats and chloroplast DNA (cpDNA) sequence variations. Both sets of markers revealed clear genetic differentiation between populations in Borneo and those in the Malay Peninsula and Sumatra (Malay/Sumatra). However, in the south‐western part of Borneo, genetic admixture of the lineages was observed in the two marker types. Coalescent simulation based on cpDNA sequence variation suggested that the two lineages arose 0.28–0.09 million years before present and that following their divergence migration from Malay/Sumatra to Borneo strongly exceeded migration in the opposite direction. We conclude that the genetic structure of S. leprosula was largely formed during the middle Pleistocene and was subsequently modified by eastward migration across the subaerially exposed Sunda Shelf. 相似文献
88.
Mohamad Radwan Almofti Hideyoshi Harashima Yasuo Shinohara Ammar Almofti Wenhao Li Hiroshi Kiwada 《Molecular membrane biology》2013,30(1):35-43
In order to identify factors affecting cationic Iiposome-mediated gene transfer, the relationships were examined among cationic liposome/DNA complex (lipoplex)-cell interactions, lipoplex size and lipoplex-mediated transfection (lipofection) efficiency. It was found that lipofection efficiency was determined mainly by lipoplex size, but not by the extent of lipoplex-cell interactions including binding, uptake or fusion. In addition, it was found that serum affected mainly lipoplex size, but not lipoplex-cell interactions, which effect was the major reason behind the inhibitory effect of serum on lipofection efficiency. It was concluded that, in the presence or absence of serum, lipoplex size is a major factor determining Iipofection efficiency. Moreover, in the presence or absence of serum, lipoplex size was found to affect lipofection efficiency by controlling the size of the intracellular vesicles containing lipoplexes after internalization, but not by affecting lipoplex-cell interactions. In addition, large lipoplex particles showed, in general, higher lipofection efficiency than small particles. These results imply that, by controlling lipoplex size, an efficient lipid delivery system may be achieved for in vitro and in vivo gene therapy. 相似文献
89.
Minami Kumazaki Shunsuke Noguchi Yuki Yasui Junya Iwasaki Haruka Shinohara Nami Yamada Yukihiro Akao 《The Journal of nutritional biochemistry》2013,24(11):1849-1858
Much evidence indicates that various naturally occurring compounds have an anti-cancer effect, but the detailed mechanisms are not well understood. In this study, we selected anti-cancer phytochemicals such as epigallocatechin-3-gallate (EGCG), resveratrol (RES) and α-mangostin (α-M), all of which are well-characterized chemopreventive agents. We sought to elucidate the mechanism of their anti-cancer effects and the synergistic effects obtained by combined treatment with the anti-cancer drug 5-fluorouracil (5-FU) in three human colon cancer cell lines. The numbers of viable cells were consistently decreased by the treatment with EGCG, RES or α-M at more than 10 μM in all three cell lines tested. All compounds mainly induced apoptosis and suppressed the PI3K/Akt signaling pathway. Additionally, α-M, which had the greatest PI3K/Akt-suppressing activity, also suppressed MAP kinase (MAPK)/Erk1/2 signaling. Importantly, the combination treatment with RES and 5-FU induced a remarkably synergistic enhancement of growth inhibition and apoptosis through the additional suppression of the MAPK/Erk1/2 signaling pathway in colon cancer DLD-1 cells. Interestingly, RES increased the intracellular expression level of miR-34a, which down-regulated the target gene E2F3 and its downstream Sirt1, resulting in growth inhibition. These findings indicate that these compounds functioned as chemosensitizers when combined with anti-cancer drugs through the modulation of apoptotic and growth-related signaling pathways. Also, RES exerted its anti-cancer activity in part through a newly defined mechanism, i.e., the miR-34a/E2F3/Sirt1 cascade. 相似文献
90.
Akira Hayashi Kyosuke Kinoshita Yoshihiko Kotani 《Bioscience, biotechnology, and biochemistry》2013,77(8):1705-1709
The phase change for an amylose–butanol complex solution in 10% of dimethylsulfoxide was investigated as a function of temperature. The phase change was determined with measurements of the turbidity, fluorescent depolarization, and viscosity. The phase diagram obtained was qualitatively similar to that for an amylose solution. From the result, the change in solution phase for the amylose–butanol complex is suggested to be similar to that for amylose, i.e., when the solution cools from a higher temperature, amylose molecules in the complex solution change the conformation from a random coil to an interrupted helix, and then separate into two phases. Coacervate particles resulting from the phase separation coalesce with each other to yield precipitates.An adsorption of uranine on amylose was studied to ascertain its relationship with the fluorescent depolarization method used for detecting phase changes in solution. The result showed that uranine was adsorbed on amylose chains but not on the amylose–butanol complex. 相似文献