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991.
Activity and population structure of nitrifying bacteria in an activated-sludge reactor containing polymer beads 总被引:1,自引:0,他引:1
Photo-crosslinked polymer beads were introduced into a laboratory activated-sludge unit containing municipal sewage sludge and the effect on nitrifying capacity was examined. The ammonia load started at a nitrogen-loading rate of 0.02 kg m(-3) day(-1) and was increased stepwise. It was found that the bead-containing unit could almost completely oxidize ammonia (over 95%) up to a nitrogen-loading rate of 0.216 kg m(-3) day(-1), whereas the maximum loading rate of the control unit (without polymer beads) was 0.096 kg m(-3) day(-1). The nitrifying potential of suspended and bead-associated organisms in the bead-containing unit was measured under different loading conditions. It was found that the bead-associated organisms exhibited high specific activities under high loading conditions and that the contribution of the bead-associated organisms to nitrification was greater than that of the suspended solids under these conditions. The bacterial population dynamics in the suspended solids and bead-associated organisms were analysed by denaturing gradient gel electrophoresis (DGGE) of PCR-amplified 16S rRNA gene fragments and by fluorescence in situ hybridization with group-specific probes. Among the known nitrifying organisms, ammonia-oxidizing beta-proteobacteria and Nitrospira-related organisms were detected by these approaches. A comparison of the activity dynamics and population dynamics, however, suggested a possibility that other organisms may also have been involved in the nitrification process under high loading conditions. 相似文献
992.
993.
Yamagishi N Nishihori H Ishihara K Ohtsuka K Hatayama T 《Biochemical and biophysical research communications》2000,272(3):850-855
Hsp105alpha and Hsp105beta are stress proteins found in various mammals including human, mouse, and rat, which belong to the Hsp105/Hsp110 protein family. To elucidate their physiological functions, we examined here the chaperone activity of these stress proteins. Hsp105alpha and Hsp105beta prevented the aggregation of firefly luciferase during thermal denaturation, whereas the thermally denatured luciferase was not reactivated by itself or by rabbit reticulocyte lysate (RRL). On the other hand, Hsp105alpha and Hsp105beta suppressed the reactivation of thermally denatured luciferase by RRL and of chemically denatured luciferase by Hsc70/Hsp40 or RRL. Furthermore, although Hsp105alpha and Hsp105beta did not show ATPase activity, the addition of Hsp105alpha or Hsp105beta to Hsc70/Hsp40 enhanced the amount of hydrolysis of ATP greater than that of the Hsp40-stimulated Hsc70 ATPase activity. These findings suggest that Hsp105alpha and Hsp105beta are not only chaperones that prevent thermal aggregation of proteins, but also regulators of the Hsc70 chaperone system in mammalian cells. 相似文献
994.
Niikura T Murayama N Hashimoto Y Ito Y Yamagishi Y Matsuoka M Takeuchi Y Aiso S Nishimoto I 《Biochemical and biophysical research communications》2000,274(2):445-454
APP is a precursor of beta amyloid deposited in Alzheimer's disease (AD). Although genetic studies established that mutations in APP cause familial AD (FAD), the mechanism for neuronal death by FAD mutants has not been well understood. We established neuronal cells (F11/EcR/V642I cells) in which V642I APP was inducibly expressed by ecdysone. Treatment with ecdysone, but not vehicle, killed most cells within a few days, with rounding, shrinkage, and detachment as well as nuclear fragmentation. Death was suppressed by Ac-DEVD-CHO and pertussis toxin. Electron microscopic analysis revealed that apoptosis occurred in ecdysone-treated cells. V642I-APP-induced death was suppressed by the anti-AD factors estrogen and apoE2. These data demonstrate not only that expression of this FAD gene causes neuronal apoptosis, but that F11/EcR/V642I cells, the first neuronal cells with inducible FAD gene expression, provide a useful model system in investigating AD disorders. 相似文献
995.
996.
997.
Goshi Sato Jun-ichi Kojima Hinako Horikoshi Fuki Saito-Morooka 《Entomological Science》2022,25(1):e12502
Thatched roofs are artificial environments that serve as nesting sites for a variety of insects, including tube-nesting wasps, but they have been declining drastically in recent years. In this study, we investigated the nesting habits of a eumenine wasp, Symmorphus apiciornatus, nesting in a group at thatched roofs in a northern part of Ibaraki Prefecture, central Japan. Genetic diversity and genetic structure in the area were also investigated. Sex ratios at most study sites were not biased. Males emerged first and waited for females to mate around the natal nests, suggesting a high possibility of breeding between the wasps having emerged at a given thatched roof under the recent situation where there has been a drastic reduction in the number of houses with a thatched roof. Nevertheless, the genetic diversity in a given local population or a thatched roof was relatively high and significant genetic differentiation among thatched roofs was not detected. 相似文献
998.
Noguchi S Komiya T Eguchi H Shirahata A Nikawa J Kawamura M 《The Journal of membrane biology》2007,215(2-3):105-110
The monoclonal antibody to the β-subunit of H+/K+-ATPase (mAbHKβ) cross-reacts with a protein that acts as a molecular chaperone for the structural maturation of sarcoplasmic
reticulum (SR) Ca2+-ATPase. We partially purified a mAbHKβ-reactive 65-kDa protein from Xenopus ovary. After in-gel digestion and peptide sequencing, the 65-kDa protein was identified as methionine aminopeptidase II (MetAP2).
The effects of MetAP2 on SR Ca2+-ATPase expression were examined by injecting the cRNA for MetAP2 into Xenopus oocytes. Immunoprecipitation and pulse-chase experiments showed that MetAP2 was transiently associated with the nascent SR
Ca2+-ATPase. Synthesis of functional SR Ca2+-ATPase was facilitated by MetAP2 and prevented by injecting an antibody specific for MetAP2. These results suggest that MetAP2
acts as a molecular chaperone for SR Ca2+-ATPase synthesis. 相似文献
999.
Identification of putative target genes of bZIP19, a transcription factor essential for Arabidopsis adaptation to Zn deficiency in roots 下载免费PDF全文
1000.
Masami TANAKA Minoru WATANABE Izuru YOKOMI Naoki MATSUMOTO Katsuko SUDO Hitoshi SATOH Tsuneo IGARASHI Azusa SEKI Hitoshi AMANO Kiyoshi OHURA Kakei RYU Shunichi SHIBATA Motohiko NAGAYAMA Jun-ichi TANUMA 《Experimental Animals》2015,64(2):121-128
Rats with dwarfism accompanied by skeletal abnormalities, such as shortness of the limbs,
tail, and body (dwarf rats), emerged in a Jcl-derived Sprague-Dawley rat colony maintained
at the Institute for Animal Experimentation, St. Marianna University Graduate School of
Medicine. Since the dwarfism was assumed to be due to a genetic mutation based on its
frequency, we bred the dwarf rats and investigated their characteristics in order to
identify the causative factors of their phenotypes and whether they could be used as a
human disease model. One male and female that produced dwarf progeny were selected, and
reproduction was initiated by mating the pair. The incidence of dwarfism was 25.8% among
the resultant litter, and dwarfism occurred in both genders, suggesting that it was
inherited in an autosomal recessive manner. At 12 weeks of age, the body weights of the
male and female dwarf rats were 40% and 57% of those of the normal rats, respectively. In
soft X-ray radiographic and histological examinations, shortening and hypoplasia of the
long bones, such as the tibia and femur, were observed, which were suggestive of
endochondral ossification abnormalities. An immunohistochemical examination detected an
aggrecan synthesis disorder, which might have led to delayed calcification and increased
growth plate thickening in the dwarf rats. We hypothesized that the principal
characteristics of the dwarf rats were systemically induced by insufficient cartilage
calcification in their long bones; thus, we named them cartilage calcification
insufficient (CCI) rats. 相似文献