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1.
Phys Rev Lett ; 132(20): 203001, 2024 May 17.
Article in English | MEDLINE | ID: mdl-38829062

ABSTRACT

We report on the anisotropic photodetachment of positronium negative ions, followed by the dissociation into p-wave electrons and positronium atoms, with a linearly polarized laser beam. We have observed a strong recoil effect of the photoelectrons on the translation momentum of the dissociated positronium atoms. With polarization angle-resolved measurements, the asymmetry parameter of the photoemission angular distribution of the ions at a photon energy of 1.165 eV was determined to be 1.97±0.04(stat)±0.07(syst), in agreement with a theoretical prediction. The present method can be applied to explore the unrevealed dissociation dynamics of exotic particle systems and their manipulation with polarized light.

3.
Biol Reprod ; 91(2): 45, 2014 Aug.
Article in English | MEDLINE | ID: mdl-24920040

ABSTRACT

The Mos-MAPK signaling pathway involving the Mos-MEK1/2-ERK1/2-RSK1/2/3 or MSK1-EMI2 cascade is directly linked to metaphase-II arrest of vertebrate oocytes. In this study, we examined whether p38, a member of the MAPK subfamily, is regulated under the control of Mos and contributes to metaphase-II arrest in the mouse oocyte. Morpholino oligonucleotide-mediated depletion of Mos revealed a remarkable decrease in phosphorylation of p38. Simultaneous treatment of oocytes with two chemical inhibitors of p38 and MEK1/2 induced both release from metaphase II and degradation of cyclin B1, whereas the treatment with each of these two inhibitors had little effect. Moreover, phosphorylation of EMI2 was dramatically abolished by addition of the two inhibitors. Indeed, MNK1, a kinase downstream of p38, exhibited the ability to phosphorylate EMI2. These results suggest that in addition to the Mos-MEK1/2 pathway, the Mos-mediated p38 pathway may be implicated in metaphase-II arrest.


Subject(s)
Cell Cycle Checkpoints/physiology , F-Box Proteins/metabolism , Metaphase/physiology , Oocytes/cytology , Protein Serine-Threonine Kinases/metabolism , p38 Mitogen-Activated Protein Kinases/metabolism , Amino Acid Sequence , Animals , F-Box Proteins/genetics , Mice , Oocytes/physiology , Phosphorylation , Protein Serine-Threonine Kinases/genetics , p38 Mitogen-Activated Protein Kinases/genetics
4.
Cancer Lett ; 329(2): 243-52, 2013 Feb 28.
Article in English | MEDLINE | ID: mdl-23196056

ABSTRACT

We previously identified genes associated with Snail-mediated squamous cell carcinoma (SCC) invasiveness, in which we observed significant elevation of Cyr61 expression. In this study, SCC cell lines overexpressing Cyr61 exhibited constitutive activation of Rho A and upregulated invasiveness without the disruption of homophilic cell attachment. Humoral Cyr61 enhanced further production of endogenous Cyr61 by SCC cells, which stimulated collective cell migration and the development of an invasive tumor nest. We propose a Cyr61-dependent model for the development of invasive SCC nest, whereby a subset of tumor cells that highly produce Cyr61 may direct other tumor cells to undergo collective cell migration, resulting in a formation of primary SCC mass.


Subject(s)
Carcinoma, Squamous Cell/pathology , Cell Movement , Cysteine-Rich Protein 61/metabolism , Mouth Neoplasms/pathology , Transcription Factors/physiology , Binding Sites , Carcinoma, Squamous Cell/metabolism , Cell Line, Tumor , Epithelial-Mesenchymal Transition , Feedback, Physiological , Gene Expression , Gene Expression Regulation, Neoplastic , Genes, Reporter , Humans , Integrins/metabolism , Luciferases, Renilla/biosynthesis , Luciferases, Renilla/genetics , Mouth Neoplasms/metabolism , Neoplasm Invasiveness , Promoter Regions, Genetic , Signal Transduction , Snail Family Transcription Factors , Transcription Factors/genetics , Transcription Factors/metabolism
5.
Cancer Lett ; 307(2): 227-36, 2011 Aug 28.
Article in English | MEDLINE | ID: mdl-21570764

ABSTRACT

We found a linear correlation between the Prostaglandin E(2) (PGE(2)) amount and the NR4A2 expression in oral squamous cell carcinoma (SCC) tissues through a statistical analysis among 41 clinical cases. In SCC cell lines, PGE(2) receptor (EP) ligation by exogenous PGE(2) promoted the NR4A2 expression in the cAMP/protein kinase A (PKA)-dependent manner. The process required a nature of SCC cell represented by constitutive activated epidermal growth factor receptor (EGFR) family. Targeted inactivation of the EGFRs interfered the PGE(2)-dependent NR4A2 expression. The PGE(2)-dependent NR4A2 induction is essential for the resistance to anti-cancer drug-induced apoptosis especially in SCC cells which showed constitutive EGFRs activity via autocrine epiregulin, a ligand for EGFRs. Conversely, SCC cells which lack epiregulin expression in their nature could gain the ability to promote the NR4A2 expression in response to PGE(2) and attain the resistance to anti-cancer drug-induced apoptosis under the existence of exogenous epiregulin. These findings suggest that susceptibility of SCC to anti-cancer drug could be compromised when PGE(2) was delivered in the microenvironment of SCC cells supported by constitutive EGFR family activities as their nature.


Subject(s)
Antineoplastic Agents/pharmacology , Carcinoma, Squamous Cell/pathology , Dinoprostone/pharmacology , ErbB Receptors/metabolism , Fluorouracil/pharmacology , Nuclear Receptor Subfamily 4, Group A, Member 2/biosynthesis , Base Sequence , Blotting, Western , Carcinoma, Squamous Cell/drug therapy , Cell Line, Tumor , DNA Primers , Humans , Reverse Transcriptase Polymerase Chain Reaction
6.
Org Lett ; 11(22): 5206-9, 2009 Nov 19.
Article in English | MEDLINE | ID: mdl-19856925

ABSTRACT

allo-Threonine-derived oxazaborolidinone (10 mol %) catalyzes the Friedel-Crafts alkylation of furans and indoles with simple acyclic alpha,beta-unsaturated ketones to give products with high yield and high enantioselectivity. The use of N,N-dimethylaniline (2.5-10 mol %) as an additive is essential for enantioselectivity.


Subject(s)
Boranes/chemistry , Furans/chemical synthesis , Heterocyclic Compounds, 1-Ring/chemistry , Indoles/chemical synthesis , Ketones/chemistry , Alkylation , Catalysis , Furans/chemistry , Indoles/chemistry , Molecular Structure , Stereoisomerism
7.
J Org Chem ; 73(1): 212-8, 2008 Jan 04.
Article in English | MEDLINE | ID: mdl-18052389

ABSTRACT

allo-Threonine-derived O-acyl-B-phenyl-oxazaborolidinones are demonstrated to be powerful and highly enantioselective Lewis acid catalysts for the Diels-Alder reaction of simple acyclic enone dienophiles, expanding the scope of ketone dienophiles and dienes. With 10 to 20 mol % of catalyst, the Diels-Alder adducts are obtained in 76-98% ee with high endo-selectivity. The catalyst exhibits high activity for the reaction with the less reactive beta-substituted dienophiles and the less reactive 1,3-cycohexadiene and 1,3-butadiene derivatives. The application of the catalysts to the Diels-Alder reaction of furan is also described.


Subject(s)
Heterocyclic Compounds, 1-Ring/chemistry , Ketones/chemistry , Ketones/chemical synthesis , Boranes , Catalysis , Cyclization , Molecular Structure , Stereoisomerism
8.
Hum Cell ; 17(4): 177-80, 2004 Dec.
Article in English | MEDLINE | ID: mdl-16035501

ABSTRACT

This study was undertaken to determine the expression time of fertilization and oocytes activation abilities of spermatids in the mouse. When elongating or elongated spermatids isolated from fresh testes of adult males (B6D2F1) were injected into mature mouse oocytes, both spermatids could activate the mature oocytes and occur fertilization. On the one hand, the round spermatids could not activate mature oocytes, when microinjected into oocytes. In some experiments, recovered round spermatids were cultured under co-culture systems using Sertoli cells as a feeder cell. Under the co-culture system, developed elongating spermatids could stimulate and fertilized mature oocytes. These results indicate that the start of oocyte activation appearance is between the stage of round spermatid and elongating spermatids and the activation ability increases with the advance of spermiogensis. On the other hand, round spermatids isolated from males of ICR strain mouse already have the oocyte activation ability and the fertilizing ability. The result obtained suggests that the expression time of the oocyte activating ability is difficult between the mouse strain.


Subject(s)
Fertilization , Oocytes/physiology , Sperm-Ovum Interactions/physiology , Spermatids/cytology , Spermatids/physiology , Animals , Cells, Cultured , Female , Male , Mice , Sertoli Cells , Sperm Injections, Intracytoplasmic
9.
Brain Res Dev Brain Res ; 140(1): 85-92, 2003 Jan 10.
Article in English | MEDLINE | ID: mdl-12524179

ABSTRACT

Myelin transcription factor 1 (MyT1) is a zinc-dependent, DNA-binding protein, and is known to be expressed in early progenitors of oligodendrocytes. We examined the immunoreactivity of MyT1 in developing human brains and brains with periventricular leukomalacia (PVL) to understand the relationship between the expression of MyT1 and myelination in PVL brains. MyT1-positive glial cells were first detected at 19 gestational weeks (GWs) and then gradually increased until 26-29 GWs in the control group. Then they decreased and became very rare at 1 year of age. The expression of MyT1 immunoreactivity shifted from the nucleus to the cytoplasm of the glial cells in the developmental time course. In the chronic stage of PVL, MyT1-positive cells were significantly increased around necrotic foci and some of the regions were coincident with increasing MBP and PLP immunoreactivity. These results may reflect myelin repair on dysmyelination around PVL areas. Therefore, MyT1 may play an important role in the myelin repair in PVL regions.


Subject(s)
Brain/pathology , DNA-Binding Proteins/metabolism , Leukomalacia, Periventricular/pathology , Transcription Factors/metabolism , Aging , Amino Acid Sequence , Autopsy , Brain/growth & development , Cerebral Ventricles/growth & development , Cerebral Ventricles/pathology , DNA-Binding Proteins/analysis , DNA-Binding Proteins/chemistry , Female , Gestational Age , Humans , Immunohistochemistry , Infant , Infant, Newborn , Molecular Sequence Data , Myelin Basic Protein/metabolism , Peptide Fragments/chemistry , Pregnancy , Transcription Factors/analysis , Transcription Factors/chemistry
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