Publish in OALib Journal

ISSN: 2333-9721

APC: Only $99


Search Results: 1 - 10 of 297 matches for " AKIHO YOKOTA "
All listed articles are free for downloading (OA Articles)
Page 1 /297
Display every page Item
Physiological and Biochemical Responses to Aluminum Stress in the Root of a Biodiesel Plant Jatropha curcas L.
HAYATI Journal of Biosciences , 2012,
Abstract: We investigated J. curcas responses to aluminum stress, histochemically and biochemically. Histochemical stainings were observed to analysis aluminum accumulation, lipid peroxidation and the loss of plasma membrane integrity on the surface and tissue of the root apex. Enzymatic analysis was conducted to measure malate content in leaf, root and malate efflux in the medium. We used M. malabathricum as a comparison for Al-tolerance plant. J. curcas root elongation was inhibited by 0.4 mM AlCl3, while M. malabathricum root elongation was inhibited by 0.8 mM AlCl3 treatment. Inhibition of root elongation has high correlation with Al accumulation in the root apex, which caused lipid degradation and cell death. Generally, malate content in J. curcas leaf and root was higher than that in M. malabathricum. In the contrary malate efflux from the root into the medium was lower. J. curcas root has a different pattern compared to M. malabathricum in malate synthesis and malate secretion when treated with a different Al concentration. We categorized J. curcas acc IP3 as more sensitive to aluminum than M. malabathricum.
MtnBD Is a Multifunctional Fusion Enzyme in the Methionine Salvage Pathway of Tetrahymena thermophila
Toshihiro Nakano, Izuru Ohki, Akiho Yokota, Hiroki Ashida
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0067385
Abstract: To recycle reduced sulfur to methionine in the methionine salvage pathway (MSP), 5-methylthioribulose-1-phosphate is converted to 2-keto-4-methylthiobutyrate, the methionine precursor, by four steps; dehydratase, enolase, phosphatase, and dioxygenase reactions (catalyzed by MtnB, MtnW, MtnX and MtnD, respectively, in Bacillus subtilis). It has been proposed that the MtnBD fusion enzyme in Tetrahymena thermophila catalyzes four sequential reactions from the dehydratase to dioxygenase steps, based on the results of molecular biological analyses of mutant yeast strains with knocked-out MSP genes, suggesting that new catalytic function can be acquired by fusion of enzymes. This result raises the question of how the MtnBD fusion enzyme can catalyze four very different reactions, especially since there are no homologous domains for enolase and phosphatase (MtnW and MtnX, respectively, in B. subtilis) in the peptide. Here, we tried to identify the domains responsible for catalyzing the four reactions using recombinant proteins of full-length MtnBD and each domain alone. UV-visible and 1H-NMR spectral analyses of reaction products revealed that the MtnB domain catalyzes dehydration and enolization and the MtnD domain catalyzes dioxygenation. Contrary to a previous report, conversion of 5-methylthioribulose-1-phosphate to 2-keto-4-methylthiobutyrate was dependent on addition of an exogenous phosphatase from B. subtilis. This was observed for both the MtnB domain and full-length MtnBD, suggesting that MtnBD does not catalyze the phosphatase reaction. Our results suggest that the MtnB domain of T. thermophila MtnBD acquired the new function to catalyze both the dehydratase and enolase reactions through evolutionary gene mutations, rather than fusion of MSP genes.
Bacterial variations on the methionine salvage pathway
Agnieszka Sekowska, Valérie Dénervaud, Hiroki Ashida, Karine Michoud, Dieter Haas, Akiho Yokota, Antoine Danchin
BMC Microbiology , 2004, DOI: 10.1186/1471-2180-4-9
Abstract: This work uses genome in silico analysis to propose methionine salvage pathways for Klebsiella pneumoniae, Leptospira interrogans, Thermoanaerobacter tengcongensis and Xylella fastidiosa. Experiments performed with mutants of B. subtilis and Pseudomonas aeruginosa substantiate the hypotheses proposed. The enzymes that catalyze the reactions are recruited from a variety of origins. The first, ubiquitous, enzyme of the pathway, MtnA (methylthioribose-1-phosphate isomerase), belongs to a family of proteins related to eukaryotic intiation factor 2B alpha. mtnB codes for a methylthioribulose-1-phosphate dehydratase. Two reactions follow, that of an enolase and that of a phosphatase. While in B. subtilis this is performed by two distinct polypeptides, in the other organisms analyzed here an enolase-phosphatase yields 1,2-dihydroxy-3-keto-5-methylthiopentene. In the presence of dioxygen an aci-reductone dioxygenase yields the immediate precursor of methionine, ketomethylthiobutyrate. Under some conditions this enzyme produces carbon monoxide in B. subtilis, suggesting a route for a new gaseous mediator in bacteria. Ketomethylthiobutyrate is finally transaminated by an aminotransferase that exists usually as a broad specificity enzyme (often able to transaminate aromatic aminoacid keto-acid precursors or histidinol-phosphate).A functional methionine salvage pathway was experimentally demonstrated, for the first time, in P. aeruginosa. Apparently, methionine salvage pathways are frequent in Bacteria (and in Eukarya), with recruitment of different polypeptides to perform the needed reactions (an ancestor of a translation initiation factor and RuBisCO, as an enolase, in some Firmicutes). Many are highly dependent on the presence of oxygen, suggesting that the ecological niche may play an important role for the existence and/or metabolic steps of the pathway, even in phylogenetically related bacteria. Further work is needed to uncover the corresponding steps when dioxygen is sc
Ratna Yuniati,Utut Widyastuti1,2,,Didy Sopandie,Akiho Yokota
Makara Seri Sains , 2011,
Abstract: Actin is a major component of the plant cytoskeleton, so all cells contain this protein. Actin is expressed constitutivelyand is involved in basic housekeeping functions required for cell maintenance. Because of this, it has been frequentlyused as an internal control to normalize changes in gene expressions analysis. Actually, the information of nucleotidesequence of actin gene of Jatropha curcas L. population IP-2P from Indonesia is not available yet. The objective of thisresearch was to isolate, clone and characterize cDNA of actin genes of J. curcas IP-2P. Three partial actin genesequences had been successfully isolated by PCR using total cDNA as template, and actin primer designed fromconserved region of Arabidopsis thaliana. Nucleotide sequence analysis showed that the length of JcACT fragment is610, 534, and 701 bp encoding 203, 177, and 234 amino acids respectively. Local alignment analysis based on mRNAsequences shows that JcACT fragment shares 98% similarity with actin mRNA of Hevea brasiliensis and 99% withactin mRNA of Ricinus communis. Based on deduced amino acid sequence, JcACT is 100% identical to actins fromPrunus salicina, Gossypium hirsutum, and Betula luminifera. Even though these clones of cDNA are not completed yet,they can be used as reference in J. curcas L. gene expression analysis.
Prosody and Quantifier Float in Japanese  [PDF]
Kenji Yokota
Open Journal of Modern Linguistics (OJML) , 2013, DOI: 10.4236/ojml.2013.31011
Abstract: The paper investigates the information structure that licenses the Japanese floating numeral quantifier (FNQ) in terms of prosody and context from the point of view that the pitch reset on the FNQ affects the information structure and plays a crucial role in determining the interpretation of the FNQ. I will show that FNQ sentences are potentially ambiguous between an event-quantifier reading (i.e., a VP-related FNQ reading), and an object-quantifier reading (i.e., an NP-related FNQ reading) where such a reading is possible. The syntactic and semantic difference yields distinct prosodic phrasings (in accordance with information-structure) which contribute to the disambiguation of the two readings (and hence the grammaticality).
On the Distributive and Non-Distributive Interpretation in Japanese  [PDF]
Kenji Yokota
Open Journal of Modern Linguistics (OJML) , 2014, DOI: 10.4236/ojml.2014.44046
Abstract: Through an analysis of two different types of floating numeral quantifier (FNQ) constructions in Japanese, the present paper investigates the distributive and non-distributive interpretation in Japanese. Discussion of the interpretative issues related to ambiguity and intonation has indicated that FNQs are potentially ambiguous, offering both distributive and non-distributive readings.
Towards a Proper Treatment of “NP-Related” Floating Numeral Quantifiers in Japanese  [PDF]
Kenji Yokota
Open Journal of Modern Linguistics (OJML) , 2015, DOI: 10.4236/ojml.2015.54033
Abstract: One of the central questions in linguistics is whether or not the Japanese floating numeral quantifier (FNQ) is always a distributive operator, as Gunji and Hasida (1998), Nakanishi (2004, 2007, 2008), and Kobuchi (2003, 2007) contend. This paper argues against their view and that the interpretive ambiguity is resolved if the semantic ambiguity arises due to the existence of the two different types of FNQs. It is argued that, discourse-semantically, what is crucial to the distinction between the two types of FNQs is whether an FNQ is interpreted via quantificational adverbs or quantificational determiners. This distinction is required when variance in FNQ interpretation is considered. In particular, it is shown that NP-related FNQs have much in common with referential (-like) nouns, functioning as discourse anaphoric items.
Endoscopic submucosal dissection for superficial esophageal squamous cell neoplasms
Kuniomi Honda,Hirotada Akiho
World Journal of Gastrointestinal Pathophysiology , 2012, DOI: 10.4291/wjgp.v3.i2.44
Abstract: Endoscopic resection is an effective treatment for non-invasive esophageal squamous cell neoplasms (ESCNs). Endoscopic mucosal resection (EMR) has been developed for small localized ESCNs as an alternative to surgical therapy because it shows similar effectiveness and is less invasive than esophagectomy. However, EMR is limited in resection size and therefore piecemeal resection is performed for large lesions, resulting in an imprecise histological evaluation and a high frequency of local recurrence. Endoscopic submucosal dissection (ESD) has been developed in Japan as one of the standard endoscopic resection techniques for ESCNs. ESD enables esophageal lesions, regardless of their size, to be removed en bloc and thus has a lower local recurrence rate than EMR. The development of new devices and the establishment of optimal strategies for esophageal ESD have resulted in fewer complications such as perforation than expected. However, esophageal stricture after ESD may occur when the resected area is larger than three-quarters of the esophageal lumen or particularly when it encompasses the entire circumference; such a stricture requires multiple sessions of endoscopic balloon dilatation. Recently, oral prednisolone has been reported to be useful in preventing post-ESD stricture. In addition, a combination of chemoradiotherapy (CRT) and ESD might be an alternative therapy for submucosal esophageal cancer that has a risk of lymph node metastasis because esophagectomy is extremely invasive; CRT has a higher local recurrence rate than esophagectomy but is less invasive. ESD is likely to play a central role in the treatment of superficial esophageal squamous cell neoplasms in the future.
Expression and Localization of NANOS1 in Spermatogenic Cells during Spermatogenesis in Rat  [PDF]
Sadaki Yokota, Yuko Onohara
CellBio (CellBio) , 2013, DOI: 10.4236/cellbio.2013.21001

Expression and localization of NANOS1 in the spermatogenic cells of rat testis were studied by immunofluorescence and immunoelectron microscopy. Using immunofluorescence techniques, NANOS1 was localized in the cytoplasm and discrete granules of spermatocytes and spermatids. The staining intensity of NANOS1 signal varied depending upon the stage of the cycle of seminiferous epithelium. Double immunofluorescence staining with antibodies against NANOS1 and DDX4 showed that several DDX4-positive compartments of nuage were also stained for NONOS1. Immunoelectron microscopy revealed that the major subcellular localization sites for NANOS1 were the chromatoid body (CB) and satellite body (SB), and the minor sites were the rest of the nuage compartments, including the irregularly-shaped perinuclear granules (ISPG), and intermitochondrial cement (IMC). Non-nuage structures such as mitochondria-associated granules (MAG), granulated body (GB), and reticulated body (RB) were also labeled by theNANOS1 antibody. In addition, NANOS1 was found in the outer dense fibers of flagella of spermatids at steps 12-19, and in the head cap of late spermatids after step 15. These results suggest that NANOS1 is one of the nuage proteins and functions mainly in the CBs as well as in the cytoplasm. NANOS1 may also have additional functions in non-nuage structures such as MAGs, GBs and RBs.

Luminescent Characteristic of Organic Compound-Containing Inorganic Crystal at Room Temperature  [PDF]
Norihito Doki, Masaaki Yokota
Advances in Chemical Engineering and Science (ACES) , 2015, DOI: 10.4236/aces.2015.54045
Abstract: The luminescent functional crystal was produced by the organic guest molecules conformation control in the inorganic host crystal matrix. Inorganic host-organic guest crystals were successfully prepared and luminescence spectra were investigated. These crystals had a phosphorescent property in room temperature by 254 nm UV irradiation. In this system, the potassium sulfate host matrix was effectively inhibited the molecular vibration of organic guest molecules by interaction between K+ and π-electrons. In addition, control of the luminescence wavelength (both fluorescence and phosphorescence) was achieved by controlling the structure of organic molecules which were taken in anorganic compound-containing inorganic crystal. Specifically, theorganic compound-containing inorganic crystals with 2-aminobenzenesulfonic acid and 2-naptylamine-1-sulfonic acid as a guest had a phosphorescence band of 455 nm and 510 nm, respectively.
Page 1 /297
Display every page Item

Copyright © 2008-2017 Open Access Library. All rights reserved.