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41.
Haruko Okamoto-Terry Kaori Umeki Mayumi Nakanishi-Matsui Masamitsu Futai 《The Journal of biological chemistry》2013,288(51):36236-36243
The proton (H+) pumping vacuolar-type ATPase (V-ATPase) is a rotary enzyme that plays a pivotal role in forming intracellular acidic compartments in eukaryotic cells. In Saccharomyces cerevisiae, the membrane extrinsic catalytic V1 and the transmembrane proton-pumping Vo complexes have been shown to reversibly dissociate upon removal of glucose from the medium. However, the basis of this disassembly is largely unknown. In the earlier study, we have found that the amino-terminal α-helical domain between Lys-33 and Lys-83 of yeast E subunit (Vma4p) in the peripheral stalk of the V1 complex has a role in glucose-dependent VoV1 assembly. Results of alanine-scanning mutagenesis within the domain revealed that the Vma4p Glu-44 is a key residue in VoV1 disassembly. Biochemical analysis on Vma4p Glu-44 to Ala, Asn, Asp, and Gln substitutions indicated that Glu-44 has a role in V-ATPase catalysis. These results suggest that Glu-44 is one of the key functional residues for subunit interaction in the V-ATPase stalk complex that allows both efficient rotation catalysis and assembly. 相似文献
42.
Effective population control of Japanese wild boar (Sus scrofa leucomystax) requires reliable information about population dynamics. Fertility rate is the fundamental component of reproduction to evaluate population dynamics. However, little is known regarding the fertility rate of Japanese wild boar. The traditional hunting practices make it difficult to obtain pregnant females and calculate the fertility rate by checking fetuses as is performed in other countries. Therefore, we focused on the corpora albicans (CA) as the CA remains in the ovaries of postpartum females after pregnancy. This study aimed to evaluate the utility of CA and estimate the fertility rate of Japanese wild boars using CA. Histological analysis of ovaries enabled us to discriminate type 1 CA, which remains for 1 year after breeding. Type 1 CA is a superior indicator compared with lactation in the non-pregnancy season because it allows verification of postpartum females over a long period. The fertility rate was calculated by the combination of pregnant and postpartum females using fetuses and type 1 CA from April to November. The fertility rate of the females captured after the second pregnancy season was 90.3 % during the pregnancy period and 100 % during the non-pregnancy period. The high fertility rate of adult females suggests that intensive adult female harvesting is needed. Our new method to determine fertility rates contributes to developing a monitoring system to adequately control Japanese wild boar population. 相似文献
43.
Chihiro Handa Tadahiro Okubo Aogu Yoneyama Masashi Nakamura Mari Sakaguchi Narumi Takahashi Mayumi Okamoto Ayumi Tanaka-Oda Tanaka Kenzo Tomoaki Ichie Takao Itioka 《Journal of plant research》2013,126(1):73-79
Macaranga myrmecophytes (ant-plants) provide their partner symbiotic ants (plant-ants) with food bodies as their main food, and they are protected by the plant-ants from herbivores. The amount of resource allocated to food bodies determines the plant-ant colony size and consequently determines the intensity of ant defense (anti-herbivore defense by plant-ants). As constraints in resource allocation change as plants grow, the plant-ant colony size is hypothesized to change with the ontogenesis of Macaranga myrmecophyte. To determine the ontogenetic change in the relative size of the plant-ant colony, we measured the dry weights of the whole plant-ant colony and all of the aboveground parts of trees at various ontogenetic stages for a myrmecophytic species (Macaranga beccariana) in a Bornean lowland tropical rain forest. Ant biomass increased as plant biomass increased. However, the rate of increase gradually declined, and the ant biomass appeared to reach a ceiling once trees began to branch. The ant/plant biomass ratio consistently decreased as plant biomass increased, with the rate of decrease gradually accelerating. We infer that the ontogenetic reduction in ant/plant biomass ratio is caused by an ontogenetic change in resource allocation to food rewards for ants related to the physiological changes accompanying the beginning of branching. 相似文献
44.
Mayumi Hadano Kenlo Nishida Nasahara Takeshi Motohka Hibiki Muraoka Noda Kazutaka Murakami Masahiro Hosaka 《Ecology and evolution》2013,3(6):1798-1807
Reports indicate that leaf onset (leaf flush) of deciduous trees in cool‐temperate ecosystems is occurring earlier in the spring in response to global warming. In this study, we created two types of phenology models, one driven only by warmth (spring warming [SW] model) and another driven by both warmth and winter chilling (parallel chill [PC] model), to predict such phenomena in the Japanese Islands at high spatial resolution (500 m). We calibrated these models using leaf onset dates derived from satellite data (Terra/MODIS) and in situ temperature data derived from a dense network of ground stations Automated Meteorological Data Acquisition System. We ran the model using future climate predictions created by the Japanese Meteorological Agency's MRI‐AGCM3.1S model. In comparison to the first decade of the 2000s, our results predict that the date of leaf onset in the 2030s will advance by an average of 12 days under the SW model and 7 days under the PC model throughout the study area. The date of onset in the 2090s will advance by 26 days under the SW model and by 15 days under the PC model. The greatest impact will occur on Hokkaido (the northernmost island) and in the central mountains. 相似文献
45.
Yusuke K. Kawai Kensuke P. Watanabe Akihiro Ishii Aiko Ohnuma Hirofumi Sawa Yoshinori Ikenaka Mayumi Ishizuka 《Comparative biochemistry and physiology. Part D, Genomics & proteomics》2013,8(3):201-208
The cytochrome P450 (CYP) 1–3 families are involved in xenobiotic metabolism, and are expressed primarily in the liver. Ostriches (Struthio camelus) are members of Palaeognathae with the earliest divergence from other bird lineages. An understanding of genes coding for ostrich xenobiotic metabolizing enzyme contributes to knowledge regarding the xenobiotic metabolisms of other Palaeognathae birds. We investigated CYP1–3 genes expressed in female ostrich liver using a next-generation sequencer. We detected 10 CYP genes: CYP1A5, CYP2C23, CYP2C45, CYP2D49, CYP2G19, CYP2W2, CYP2AC1, CYP2AC2, CYP2AF1, and CYP3A37. We compared the gene expression levels of CYP1A5, CYP2C23, CYP2C45, CYP2D49, CYP2G19, CYP2AF1, and CYP3A37 in ostrich liver and determined that CYP2G19 exhibited the highest expression level. The mRNA expression level of CYP2G19 was approximately 2–10 times higher than those of other CYP genes. The other CYP genes displayed similar expression levels. Our results suggest that CYP2G19, which has not been a focus of previous bird studies, has an important role in ostrich xenobiotic metabolism. 相似文献
46.
Aya Iketani Mayumi Nakamura Yuya Suzuki Koichiro Awai Yuzo Shioi 《Fungal biology》2013,117(3):173-181
A serine protease with caspase- and legumain-like activities from basidiocarps of the edible basidiomycete Flammulina velutipes was characterized. The protease was purified to near homogeneity by three steps of chromatography using acetyl-Tyr-Val-Ala-Asp-4-methylcoumaryl-7-amide (Ac-YVAD-MCA) as a substrate. The enzyme was termed FvSerP (F. velutipes serine protease). This enzyme activity was completely inhibited by the caspase-specific inhibitor, Ac-YVAD-CHO, as well as moderately inhibited by serine protease inhibitors. Based on the N-terminal sequence, the cDNA of FvSerP was identified. The deduced protease sequence was a peptide composed of 325 amino acids with a molecular mass of 34.5 kDa. The amino acid sequence of FvSerP showed similarity to neither caspases nor to the plant subtilisin-like serine protease with caspase-like activity called saspase. FvSerP shared identity to the functionally unknown genes from class of Agaricomycetes, with similarity to the peptidase S41 domain of a serine protease. It was thus concluded that this enzyme is likely a novel serine protease with caspase- and legumain-like activities belonging to the peptidase S41 family and distributed in the class Agaricomycetes. This enzyme possibly functions in autolysis, a type of programmed cell death that occurs in the later stages of development of basidiocarps with reference to their enzymatic functions. 相似文献
47.
Ayako Kitano Takeo Shimasaki Yuri Chikano Mitsutoshi Nakada Mayumi Hirose Tomomi Higashi Yasuhito Ishigaki Yoshio Endo Takahisa Takino Hiroshi Sato Yoshimichi Sai Ken-ichi Miyamoto Yoshiharu Motoo Kazuyuki Kawakami Toshinari Minamoto 《PloS one》2013,8(2)
Background and Purpose
The major obstacles to treatment of pancreatic cancer are the highly invasive capacity and resistance to chemo- and radiotherapy. Glycogen synthase kinase 3β (GSK3β) regulates multiple cellular pathways and is implicated in various diseases including cancer. Here we investigate a pathological role for GSK3β in the invasive and treatment resistant phenotype of pancreatic cancer.Methods
Pancreatic cancer cells were examined for GSK3β expression, phosphorylation and activity using Western blotting and in vitro kinase assay. The effects of GSK3β inhibition on cancer cell survival, proliferation, invasive ability and susceptibility to gemcitabine and radiation were examined following treatment with a pharmacological inhibitor or by RNA interference. Effects of GSK3β inhibition on cancer cell xenografts were also examined.Results
Pancreatic cancer cells showed higher expression and activity of GSK3β than non-neoplastic cells, which were associated with changes in its differential phosphorylation. Inhibition of GSK3β significantly reduced the proliferation and survival of cancer cells, sensitized them to gemcitabine and ionizing radiation, and attenuated their migration and invasion. These effects were associated with decreases in cyclin D1 expression and Rb phosphorylation. Inhibition of GSK3β also altered the subcellular localization of Rac1 and F-actin and the cellular microarchitecture, including lamellipodia. Coincident with these changes were the reduced secretion of matrix metalloproteinase-2 (MMP-2) and decreased phosphorylation of focal adhesion kinase (FAK). The effects of GSK3β inhibition on tumor invasion, susceptibility to gemcitabine, MMP-2 expression and FAK phosphorylation were observed in tumor xenografts.Conclusion
The targeting of GSK3β represents an effective strategy to overcome the dual challenges of invasiveness and treatment resistance in pancreatic cancer. 相似文献48.
49.
50.
Makoto Nakabayashi Naoki Shibata Emi Ishido-Nakai Mayumi Kanagawa Yota Iio Hirofumi Komori Yasufumi Ueda Noriko Nakagawa Seiki Kuramitsu Yoshiki Higuchi 《Extremophiles : life under extreme conditions》2016,20(3):275-282
TTHA0829 from Thermus thermophilus HB8 has a molecular mass of 22,754 Da and is composed of 210 amino acid residues. The expression of TTHA0829 is remarkably elevated in the latter half of logarithmic growth phase. TTHA0829 can form either a tetrameric or dimeric structure, and main-chain folding provides an N-terminal cystathionine-β-synthase (CBS) domain and a C-terminal aspartate-kinase chorismate-mutase tyrA (ACT) domain. Both CBS and ACT are regulatory domains to which a small ligand molecule can bind. The CBS domain is found in proteins from organisms belonging to all kingdoms and is observed frequently as two or four tandem copies. This domain is considered as a small intracellular module with a regulatory function and is typically found adjacent to the active (or functional) site of several enzymes and integral membrane proteins. The ACT domain comprises four β-strands and two α-helices in a βαββαβ motif typical of intracellular small molecule binding domains that help control metabolism, solute transport and signal transduction. We discuss the possible role of TTHA0829 based on its structure and expression pattern. The results imply that TTHA0829 acts as a cell-stress sensor or a metabolite acceptor. 相似文献