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1.
Kunio Takeda Atsuya Shigemura Satoshi Hamada Weicheng Gu Defu Fang Katsushi Sasa Kazuaki Hachiya 《Journal of Protein Chemistry》1992,11(2):187-192
The effect of protein conformations on the reaction rate of Ellman's reagent, 5,5-dithiobis (2-nitrobenzoic acid) (DTNB) with sulfhydryl (SH) groups of proteins was examined. The stopped-flow method was applied to follow the reaction of DTNB with SH group of two proteins, bovine serum albumin (BSA) and ovalbumin (OVA), at various concentrations of guanidine hydrochloride and urea. The rates for both the proteins were faster in guanidine than in urea. The rate sharply depended on the protein conformations, which were monitored by changes of helix contents on the basis of the circular dichroism measurements. The reaction rate of DTNB with SH groups of BSA was maximal around 2 M guanidine and 5 M urea. On the other hand, the reaction rate of DTNB with OVA was maximal at 3.5 M guanidine, while it gradually increased with an increase in the urea concentration. The amount of reactive SH group participating in the reaction with DTNB was also estimated by the absorbance change at 412 nm. The magnitudes of absorbance change for the reaction with free SH groups of OVA at low concentrations of the denaturants were appreciably smaller than those for BSA with one free SH group. Most of the four SH groups of OVA might react with DTNB above 5 M guanidine, although only a part of them did even at 9 M urea. 相似文献
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Takanori Awata Mamoru Oshiki Tomonori Kindaichi Noriatsu Ozaki Akiyoshi Ohashi Satoshi Okabe 《Applied and environmental microbiology》2013,79(13):4145-4148
The phylogenetic affiliation and physiological characteristics (e.g., Ks and maximum specific growth rate [μmax]) of an anaerobic ammonium oxidation (anammox) bacterium, “Candidatus Scalindua sp.,” enriched from the marine sediment of Hiroshima Bay, Japan, were investigated. “Candidatus Scalindua sp.” exhibits higher affinity for nitrite and a lower growth rate and yield than the known anammox species. 相似文献
4.
Localization of activated caspase-3-positive and apoptotic cells in the developing tooth germ of the mouse lower first molar 总被引:3,自引:0,他引:3
Shigemura N Kiyoshima T Sakai T Matsuo K Momoi T Yamaza H Kobayashi I Wada H Akamine A Sakai H 《The Histochemical journal》2001,33(5):253-258
This study examined the immunohistochemical detection of activated caspase-3, and its association with apoptosis, during tooth morphogenesis of the mouse lower first molar. The distribution of cells positive for caspase-3 closely corresponded with the localization of the terminal deoxynucleotidyl transferase-mediated deoxyuridine-5-triphosphate-biotin nick end labelling (TUNEL)-positive apoptotic cells through the developmental course of tooth germs from embryo day 12 (E12) to E19, thus showing that the apoptosis occurring in the developing odontogenic tissue was induced by the activation of the caspase family. The specific distribution pattern of apoptotic cells in the developing odontogenic epithelial tissue from the initiation (E12) of tooth germ to the completion of tooth crown morphology (E19) also suggests that apoptotic events are related not only to a deletion of functionally suspended cells, but also participate in initiation and the completion of tooth morphogenesis. Electron microscopic examination revealed that apoptotic cells were present in the primary enamel knot, and these apoptotic cells were phagocytized by neighbouring odontogenic epithelial cells, thus indicating the prompt disposal of any dead cells by epithelial cells. 相似文献
5.
In Situ Activity and Spatial Organization of Anaerobic Ammonium-Oxidizing (Anammox) Bacteria in Biofilms
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Tomonori Kindaichi Ikuo Tsushima Yuji Ogasawara Masaki Shimokawa Noriatsu Ozaki Hisashi Satoh Satoshi Okabe 《Applied microbiology》2007,73(15):4931-4939
We investigated autotrophic anaerobic ammonium-oxidizing (anammox) biofilms for their spatial organization, community composition, and in situ activities by using molecular biological techniques combined with microelectrodes. Results of phylogenetic analysis and fluorescence in situ hybridization (FISH) revealed that “Brocadia”-like anammox bacteria that hybridized with the Amx820 probe dominated, with 60 to 92% of total bacteria in the upper part (<1,000 μm) of the biofilm, where high anammox activity was mainly detected with microelectrodes. The relative abundance of anammox bacteria decreased along the flow direction of the reactor. FISH results also indicated that Nitrosomonas-, Nitrosospira-, and Nitrosococcus-like aerobic ammonia-oxidizing bacteria (AOB) and Nitrospira-like nitrite-oxidizing bacteria (NOB) coexisted with anammox bacteria and accounted for 13 to 21% of total bacteria in the biofilms. Microelectrode measurements at three points along the anammox reactor revealed that the NH4+ and NO2− consumption rates decreased from 0.68 and 0.64 μmol cm−2 h−1 at P2 (the second port, 170 mm from the inlet port) to 0.30 and 0.35 μmol cm−2 h−1 at P3 (the third port, 205 mm from the inlet port), respectively. No anammox activity was detected at P4 (the fourth port, 240 mm from the inlet port), even though sufficient amounts of NH4+ and NO2− and a high abundance of anammox bacteria were still present. This result could be explained by the inhibitory effect of organic compounds derived from biomass decay and/or produced by anammox and coexisting bacteria in the upper parts of the biofilm and in the upstream part of the reactor. The anammox activities in the biofilm determined by microelectrodes reflected the overall reactor performance. The several groups of aerobic AOB lineages, Nitrospira-like NOB, and Betaproteobacteria coexisting in the anammox biofilm might consume a trace amount of O2 or organic compounds, which consequently established suitable microenvironments for anammox bacteria. 相似文献
6.
Ariel Jaitovich Martín Angulo Emilia Lecuona Laura A. Dada Lynn C. Welch Yuan Cheng Galina Gusarova Ermelinda Ceco Chang Liu Masahiko Shigemura Esther Barreiro Cam Patterson Gustavo A. Nader Jacob I. Sznajder 《The Journal of biological chemistry》2015,290(14):9183-9194
Patients with chronic obstructive pulmonary disease, acute lung injury, and critical care illness may develop hypercapnia. Many of these patients often have muscle dysfunction which increases morbidity and impairs their quality of life. Here, we investigated whether hypercapnia leads to skeletal muscle atrophy. Mice exposed to high CO2 had decreased skeletal muscle wet weight, fiber diameter, and strength. Cultured myotubes exposed to high CO2 had reduced fiber diameter, protein/DNA ratios, and anabolic capacity. High CO2 induced the expression of MuRF1 in vivo and in vitro, whereas MuRF1−/− mice exposed to high CO2 did not develop muscle atrophy. AMP-activated kinase (AMPK), a metabolic sensor, was activated in myotubes exposed to high CO2, and loss-of-function studies showed that the AMPKα2 isoform is necessary for muscle-specific ring finger protein 1 (MuRF1) up-regulation and myofiber size reduction. High CO2 induced AMPKα2 activation, triggering the phosphorylation and nuclear translocation of FoxO3a, and leading to an increase in MuRF1 expression and myotube atrophy. Accordingly, we provide evidence that high CO2 activates skeletal muscle atrophy via AMPKα2-FoxO3a-MuRF1, which is of biological and potentially clinical significance in patients with lung diseases and hypercapnia. 相似文献
7.
Post-treatment of anaerobic wastewater was undertaken to biologically oxidize dissolved methane, with the aim of preventing methane emission. The performance of dissolved methane oxidation and competition for oxygen among methane, ammonium, organic matter, and sulfide oxidizing bacteria were investigated using a lab-scale closed-type down-flow hanging sponge (DHS) reactor. Under the oxygen abundant condition of a hydraulic retention time of 2h and volumetric air supply rate of 12.95m(3)-airm(-3)day(-1), greater than 90% oxidation of dissolved methane, ammonium, sulfide, and organic matter was achieved. With reduction in the air supply rate, ammonium oxidation first ceased, after which methane oxidation deteriorated. Sulfide oxidation was disrupted in the final step, indicating that COD and sulfide oxidation occurred prior to methane oxidation. A microbial community analysis revealed that peculiar methanotrophic communities dominating the Methylocaldum species were formed in the DHS reactor operation. 相似文献
8.
Meligy FY Shigemura K Behnsawy HM Fujisawa M Kawabata M Shirakawa T 《In vitro cellular & developmental biology. Animal》2012,48(4):203-215
The objective of the study is to evaluate efficiency of in vitro isolation and myogenic differentiation of mesenchymal stem
cells (MSCs) derived from adipose connective tissue (AD-MSCs), bone marrow (BM-MSCs), and skeletal muscle tissue (MC-MSCs).
MSCs were isolated from adipose connective tissue, bone marrow, and skeletal muscle tissue of two adult 6-wk-old rats. Cultured
MSCs were treated with 5-azacytidine (AZA) to induce myogenic differentiation. Isolated MSCs and differentiated cells were
evaluated by immunocytochemistry (ICC), fluorescence-activated cell sorting (FACS), PCR, and RT-PCR. AD-MSCs showed the highest
proliferation rate while BM-MSCs had the lowest one. In ICC, isolated MSCs had strong CD90- and CD44-positive expression and
negative expression of CD45, CD31, and CD34, while AZA-treated MSCs had strong positive desmin expression. In FACS analysis,
AD-MSCs had the highest percentage of CD90- and CD44-positive-expressing cells (99% and 96%) followed by BM-MSCs (97% and
94%) and MC-MSCs (92% and 91%).At 1 wk after incubation with AZA treatment, the peak of myogenin expression reached 93% in
differentiated MC-MSCs, 83.3% in BM-MSCs, and 77% in AD-MSCs. MSCs isolated from adipose connective tissue, bone marrow, and
skeletal muscle tissue have the same morphology and phenotype, but AD-MSCs were the most easily accessible and had the highest
rate of growth on cultivation and the highest percentage of stem cell marker expression. Moreover, although MC-MSCs showed
the highest rate of myogenic differentiation potential and expression of myoblast markers, AD-MSCs and BM-MSCs still can be
valuable alternatives. The differentiated myoblastic cells could be an available new choice for myoblastic auto-transplantation
in regeneration medicine. 相似文献
9.
Watanabe T Ozaki N Iwashita K Fujii T Iefuji H 《Applied microbiology and biotechnology》2008,80(2):331-338
Inorganic phosphate is an essential nutrient. In general, microorganisms take up phosphorus when the extracellular phosphorus concentration is low, but not when it is high. In Saccharomyces cerevisiae, the major phosphate transporters, such as Pho84p, and acid phosphatases (APases), such as Pho5p, are regulated in parallel by the phosphate signal transduction pathway (PHO pathway). We found that PHO mutants expressing PHO84 and PHO5, even under high-P conditions, could take up phosphorus at twice the rate of the wild-type strain. The regulatory pathway for phosphorus accumulation in two wastewater treatment yeasts, Hansenula fabianii J640 and Hansenula anomala J224-1, was found to be similar to that in S. cerevisiae. We screened for mutants of these yeasts that constitutively expressed APase. Such mutants formed blue colonies on high phosphorus concentration agar plates containing 5-bromo-4-chloro-3-indolylphosphate (X-phosphate). We found four mutants of H. fabianii J640 and one mutant of H. anomala J224-1 that accumulated from 2.2 to 3.5 times more phosphorus than the parent strains. The growth rates and abilities to remove dissolved total nitrogen and dissolved organic carbon of the mutants were similar to those of the parent strains. In addition, the mutants removed 95% of dissolved total phosphorus from shochu wastewater, while the parent strain removed only 50%. 相似文献
10.
Maruyama S Miyajima N Bohgaki M Tsukiyama T Shigemura M Nonomura K Hatakeyama S 《Molecular and cellular biochemistry》2008,307(1-2):73-82
Ubiquitylation appears to be involved in the membrane trafficking system including endocytosis, exocytosis, and ER-to-Golgi
transport. We found that PIRH2, which was identified as an interacting protein for androgen receptor or p53, interacts with
and ubiquitylates the ε-subunit of coatmer complex, ε-COP. PIRH2 promotes the ubiquitylation of ε-COP in vitro and in vivo
and consequently promotes the degradation of ε-COP. The interaction between PIRH2 and ε-COP is affected by the presence of
androgen, and PIRH2 in the presence of androgen promotes ubiquitylation of ε-COP in vivo. Furthermore, overexpression of the
wild type of PIRH2 in prostate cancer cells causes downregulation of the secretion of prostate-specific antigen (PSA), a secretory
protein in prostate epithelial cells and one of diagnostic markers for prostate cancer. Our results indicate that PIRH2 functions
as a regulator for COP I complex. 相似文献