Development of a novel single step reverse genetics system for feline calicivirus

The reverse genetics system is a useful tool to generate infectious virus. Feline calicivirus (FCV), a member of the genus Vesivirus in the family Caliciviridae, has a positive sense, single-stranded RNA genome. Two reverse genetics systems have been established for FCV; however, these methods need multi-steps to produce progeny infectious virus. In this study, a novel plasmid-based single step reverse genetics system for FCV has been developed. The plasmid carries FCV F4 strain genomic sequence with an introduced silent mutation. In addition, at the 5'- and 3'-end, a human elongation factor-1α promoter and a cis-acting hepatitis delta virus ribozyme following poly-A, were added, respectively. When the plasmid was transfected into Crandell-Rees feline kidney cells, progeny FCV was generated. The reverse genetics system-derived FCV (rFCV) showed similar growth kinetics and antigenic characteristics and had identical genomic terminals to those of the original FCV F4 strain. The presence of the introduced silent mutation in the rFCV genomic cDNA supported that the progeny virus was originated from the plasmid. This novel FCV reverse genetics system is simple and can be used to evaluate the functions of the viral genome, proteins, and phenotypic characterization of FCV strains in the future.

Magneto-optic spatial light modulator with submicron-size magnetic pixels for wide-viewing-angle holographic displays

Spatial light modulators (SLMs) with submicron-size pixels are promising devices for use in wide-viewing-angle glasses-free holographic 3D displays. In accordance with estimations, an SLM with 1 μm pitch pixels can display holographic images over viewing angles of 30 deg. In the present work, we have studied magneto-optic SLMs (MOSLMs) with submicron-size pixels for wide-viewing-angle holographic displays that are driven by thermomagnetic recording. Amorphous TbFe films were used as a magneto-optic material. The MOSLM with an 800 nm diameter pixels array displayed wide-viewing-angle holographic images. These results demonstrated that MOSLMs with submicron-size pixels have promise for glasses-free holographic 3D displays.

Characterization of putative toxin/antitoxin systems in Vibrio parahaemolyticus

AIM

To obtain more information about the toxin/antitoxin (TA) systems in the Vibrio genus and also to examine their involvement in the induction of a viable but nonculturable (VBNC) state, we searched homologues of the Escherichia coli TA systems in the Vibrio parahaemolyticus genome.

METHODS AND RESULTS

We found that a gene cluster, vp1842/vp1843, in the V. parahaemolyticus genome database has homology to that encoding the E. coli TA proteins, DinJ/YafQ. Expression of the putative toxin gene vp1843 in E. coli cells strongly inhibited the cell growth, while coexpression with the putative antitoxin gene vp1842 neutralized this effect. Mutational analysis identified Lys37 and Pro45 in the gene product VP1843 of vp1843 as crucial residues for the growth retardation of E. coli cells. VP1843, unlike the E. coli toxin YafQ, has no protein synthesis inhibitory activity, and that instead the expression of vp1843 in E. coli caused morphological change of the cells.

CONCLUSIONS

The gene cluster vp1842/vp1843 encodes the V. parahaemolyticus TA system; VP1843 inhibits cell growth, whereas VP1842 serves as an antitoxin by forming a stable complex with VP1843.

SIGNIFICANCE AND IMPACT OF THE STUDY

The putative toxin, VP1843, may be involved in the induction of the VBNC state in V. parahaemolyticus by inhibiting cell division.

Electronic structure of a quasi-freestanding MoS₂ monolayer

Several transition-metal dichalcogenides exhibit a striking crossover from indirect to direct band gap semiconductors as they are thinned down to a single monolayer. Here, we demonstrate how an electronic structure characteristic of the isolated monolayer can be created at the surface of a bulk MoS2 crystal. This is achieved by intercalating potassium in the interlayer van der Waals gap, expanding its size while simultaneously doping electrons into the conduction band. Our angle-resolved photoemission measurements reveal resulting electron pockets centered at the K̅ and K' points of the Brillouin zone, providing the first momentum-resolved measurements of how the conduction band dispersions evolve to yield an approximately direct band gap of ∼1.8 eV in quasi-freestanding monolayer MoS2. As well as validating previous theoretical proposals, this establishes a novel methodology for manipulating electronic structure in transition-metal dichalcogenides, opening a new route for the generation of large-area quasi-freestanding monolayers for future fundamental study and use in practical applications.

Effect of hypochlorite-based disinfectants on inactivation of murine norovirus and attempt to eliminate or prevent infection in mice by addition to drinking water

We evaluated the in vitro efficacy of weak acid hypochlorous solution (WAHS) against murine norovirus (MNV) by plaque assay and compared the efficacy with diluted NaOCl (Purelox) and 70% ethanol. WAHS was as effective as 70% ethanol and diluted Purelox for 0.5-min reactions. For 0.5-min reactions in the presence of mouse feces emulsion, the efficacy of WHAS and 1:600 diluted Purelox was decreased, reducing the virus titers by 2.3 and 2.6 log₁₀, respectively, while 70% ethanol reduced the titer by more than 5 log₁₀. However, WAHS showed more than 5 log₁₀ reductions for the 5-min reaction even in the presence of feces emulsion. Since WAHS showed enough efficacy in inactivating MNV in vitro, we tried to eliminate MNV from MNV-infected mice by substituting WAHS for their drinking water. However, MNV was found to be positive in feces of mice drinking WAHS by an RT-nested PCR and plaque assay. To investigate whether hypochlorite-based disinfectants could prevent infection of a mouse with MNV, WAHS or 1:6,000 diluted Purelox was substituted for the drinking water of mice for 2 or 4 weeks, and then the mice were placed in a cage with an MNV-infected mouse. The supply of disinfectants was continued after cohabitation, but MNV was detected in the feces of all the mice at 1 week after cohabitation. In this study, we tried to eliminate and prevent MNV infection from mice by supplying hypochlorite-based disinfectants as an easy and low-cost method. Unfortunately, drinking disinfectants was ineffective, so it is important to keep the facility environment clean by use of effective disinfectants. Also, animals introduced into facilities should be tested as MNV free by quarantine and periodically confirmed as MNV free by microbiological monitoring.

Spin and orbital contributions to magnetically ordered moments in 5d layered perovskite Sr2IrO4

The ratio of orbital (L) and spin (S) contributions to the magnetically ordered moments of a 5d transition metal oxide, Sr2IrO4 was evaluated by nonresonant magnetic x-ray diffraction. We applied an improved experimental setting that minimized the experimental error, in which we varied only the linear polarization of incident x ray at a fixed scattering angle. Strong polarization dependence of the intensity of magnetic diffraction was observed, from which we conclude that the ordered moments contain substantial contribution from the orbital degree of freedom with the ratio of <L>/<S>∼5.0, evidencing the pronounced effect of spin-orbit coupling. The obtained ratio is close to, but slightly larger than the expected value for the ideal J(eff) = 1/2 moment of a spin-orbital Mott insulator, |<J(1/2)|L(z)|J(1/2)>|/|<J(1/2)|S(z)|J(1/2)>| = 4, which cannot be accounted for by the redistribution of orbital components within the t(2g) bands associated with the elongation of the IrO6 octahedra.

Levonorgestrel-releasing intrauterine device used for dysmenorrhea: five-year literature review

Intrauterine devices (IUDs) provide highly effective, long-term, safe, reversible contraception, and are the most widely used reversible contraceptive method worldwide. The levonorgestrel-releasing IUD (LNG-IUD), originally designed for long-term contraceptives, is now recognized to provide non-contraceptive health benefits. These include severe dysmenorrhea and/or heavy menstrual bleeding associated with uterine myoma, endometriosis, and adenomyosis. This report aims to review the last five-year literature on the efficacy and safety of the LNG-IUD in women with dysmenorrhea. Dysmenorrhea has been reported to decrease in all women. LNG-IUD seems to be superior over copper-releasing IUD for improving dysmenorrhea. The LNG-IUD is beneficial for symptom recurrence and endometriotic cyst recurrence after conservative surgery for patients with severe pain related to endometriosis. There is also evidence to support its role in menstrual problems of severely obese adolescent females. Expulsion, one of the important factors for IUD acceptability, is rare but more common in women with distorted uterine cavity. In the treatment of dysmenorrhea, the LNG-IUD is equal or superior to treat with systemic progestins or oral contraceptives even in adolescent or menopausal women.

A-type antiferro-orbital ordering with I4(1)/a symmetry and geometrical frustration in the spinel vanadate MgV2O4

We conduct a detailed structural analysis of the S=1 pyrochlore antiferromagnet MgV2O4, which exhibits an antiferromagnetic ordering marginally at TN=40  K, triggered by a structural transition from cubic to tetragonal symmetry at TS=62  K, using high resolution synchrotron x-ray diffraction and convergent beam electron diffraction. We reveal that the tetragonal phase below TS has the symmetry of I4(1)/a and that the distortion pattern of VO6 octahedra is consistent with A-type antiferro-orbital ordering with alternating stacking of layers with yz/xy orbital chains and zx/xy orbital chains along the tetragonal c axis. This implies that an anisotropic coupling of V moments produced by the orbital ordering below TS primarily brings about the antiferromagnetic ordering.

Optical excitation of Josephson plasma solitons in a cuprate superconductor

Josephson plasma waves are linear electromagnetic modes that propagate along the planes of cuprate superconductors, sustained by interlayer tunnelling supercurrents. For strong electromagnetic fields, as the supercurrents approach the critical value, the electrodynamics become highly nonlinear. Josephson plasma solitons (JPSs) are breather excitations predicted in this regime, bound vortex-antivortex pairs that propagate coherently without dispersion. We experimentally demonstrate the excitation of a JPS in La1.84Sr0.16CuO4, using intense narrowband radiation from an infrared free-electron laser tuned to the 2-THz Josephson plasma resonance. The JPS becomes observable as it causes a transparency window in the opaque spectral region immediately below the plasma resonance. Optical control of magnetic-flux-carrying solitons may lead to new applications in terahertz-frequency plasmonics, in information storage and transport and in the manipulation of high-Tc superconductivity.

Amplification of all 11 RNA segments of group A rotaviruses based on reverse transcription polymerase chain reaction

Group A rotaviruses (RVA) are a major cause of acute infantile gastroenteritis. The viral genome comprises 11 double-stranded RNA segments and the respective gene segments are classified into more than eight genotypes, according to the nucleotide sequence similarities. So far, it has been difficult to amplify full-length sequences of long RNA segments of rotaviruses by one-time only RT-PCR (especially in the genes for the viral proteins VP1, VP2, VP3 and VP4). In this study, a set of universal primers to amplify all 11 segments of RVA was designed by aligning the nucleotide sequences of the typical rotavirus strains. Using these primers and a high-fidelity and rapid DNA polymerase in a one-step reverse transcription polymerase chain reaction, almost the entire length of all 11 segments of the seven rotavirus strains Wa, DS-1, Hochi, 69M, WI61, M37 and SA11-S1 were accurately and rapidly amplified. In addition, all 11 segments of rotavirus obtained from a fecal specimen were successfully amplified. In conclusion, the method described here will be useful as an RVA detection system and protocol for complete analysis of the 11 genome sequences.

Electronic superlattice revealed by resonant scattering from random impurities in Sr3Ru2O7

Resonant elastic x-ray scattering (REXS) is an exquisite element-sensitive tool for the study of subtle charge, orbital, and spin superlattice orders driven by the valence electrons, which therefore escape detection in conventional x-ray diffraction (XRD). Although the power of REXS has been demonstrated by numerous studies of complex oxides performed in the soft x-ray regime, the cross section and photon wavelength of the material-specific elemental absorption edges ultimately set the limit to the smallest superlattice amplitude and periodicity one can probe. Here we show--with simulations and REXS on Mn-substituted Sr3Ru2O7--that these limitations can be overcome by performing resonant scattering experiments at the absorption edge of a suitably-chosen, dilute impurity. This establishes that--in analogy with impurity-based methods used in electron-spin-resonance, nuclear-magnetic resonance, and Mössbauer spectroscopy--randomly distributed impurities can serve as a non-invasive, but now momentum-dependent probe, greatly extending the applicability of resonant x-ray scattering techniques.

Evidence for a cos(4φ) modulation of the superconducting energy gap of optimally doped FeTe(0.6)Se(0.4) single crystals using laser angle-resolved photoemission spectroscopy

We study the superconducting-gap anisotropy of the Γ-centered hole Fermi surface in optimally doped FeTe(0.6)Se(0.4) (T(c)=14.5 K), using laser-excited angle-resolved photoemission spectroscopy. We observe sharp superconducting (SC) coherence peaks at T=2.5 K. In contrast to earlier angle-resolved photoemission spectroscopy studies but consistent with thermodynamic results, the momentum dependence shows a cos(4φ) modulation of the SC-gap anisotropy. The observed SC-gap anisotropy strongly indicates that the pairing interaction is not a conventional phonon-mediated isotropic one. Instead, the results suggest the importance of second-nearest-neighbor electronic interactions between the iron sites in the framework of s(±)-wave superconductivity.

Cytosol and serum concentration of cytokeratin subunit-19 fragment (cyfra-21-1) in breast-cancer

Cytokeratin 19 is a subunit of cytokeratin intermediate filament. CYFRA 21-1 is a new tumor marker using monoclonal antibodies which recognize a fragment of cytokeratin 19. CYFRA 21-1 was measured in cytosol of breast cancer tissues or in sera of patients with breast cancer or benign breast diseases to study the significance of this protein as a tumor marker. The cytosol concentration of CYFRA 21-1 was elevated in cancerous tissue compared to that in adjacent noncancerous tissue, and correlated with the tumor stage or the estrogen receptor status. In the serum, the mean value and positive rate for CYFRA 21-1 (assuming 2.2 ng/ml as the cut-off value) were 0.61 ng/ml (0%) in benign breast diseases, 0.98 ng/ml (6.7%) in stage I/II primary breast cancer, 75.67 ng/ml (60.0%) in stage III/IV primary breast cancer, 45.28 ng/ml (60.0%) in recurrent breast cancer, and 0.64 ng/ml (2.6%) in those with no evidence of recurrence. From the above, we concluded that CYFRA 21-1 could be a tumor marker with high specificity in breast cancer.

GTP-binding protein and its associated event in membranes from endometrial carcinoma

Endometrial carcinoma expresses gonadotropin-releasing hormone receptor (Gn-RHR) known to be linked by heterotrimeric GTP-binding proteins (G proteins). We have examined endometrial carcinomas for the presence of G protein and its associated membrane event in isolated plasma membranes. Endometrial carcinomas surgically removed had been screened for Gn-RHR expression prior to plasma membrane isolation. G protein level was observed by immunoblotting of membrane extracts with anti-G protein antibodies. G protein-associated membrane event was observed by phosphotyrosine phosphatase (PTP) activity determined with the synthetic substrate p-nitrophenyl in a spectrophotometric assay. Immunoblotting with the specific G alpha 11 and G alpha s antibodies showed significant levels of 42-kDa and 46-kDa proteins in endometrial carcinoma membranes, respectively. The nonhydrolyzable GTP analog GTP-gamma-S stimulated the phosphatase activity in a dose-dependent manner: a half maximal effect occurred with 30 nM. These findings demonstrate the expression of G proteins and the presence G proteins-associated membrane event in endometrial carcinoma.

Matrix metalloproteinase 2 and 9 in esophageal cancer

To search for the biochemical properties of esophageal carcinoma relevant to its aggressive behavior, we studied metalloproteinases released from surgical specimens of the carcinoma. In an assay with [H-3]-labeled gelatin, esophageal carcinoma tissues showed gelatinolytic activities clearly higher than those of paired normal mucosae. EDTA and TIMP-1 could strongly suppress these activities, suggesting that the activities belong to metalloproteinases. In addition, levels of TIMP-1 expression did not show good correlation with these activities, suggesting that tumor-specific elevation of gelatinolytic activity depended on metalloproteinase per se rather than the suppression of TIMP-1-secretion. By zymographic analysis, two gelatinase bands of 82- and 62-kDa were found specifically in carcinoma tissues, in addition to the other 6 bands detected both in normal and carcinoma tissues. Immunoprecipitation and immunoblotting of gelatinases with anti-MMP-9 or anti-MMP-2 monoclonal antibody, and treatment of the enzymes with APMA showed that these 82- and 62-kDa gelatinases were cleaved products of MMP-9 and MMP-2, respectively. These results imply that enhanced secretion and proteolytic activation of MMP-2 and MMP-9 take place specifically in the esophageal carcinoma tissues. Moreover, the levels of gelatinolytic activity expressed good correlation with the organ metastasis rate of the carcinoma, suggesting that MMPs play an important role in tumor metastasis.

Phosphotyrosine phosphatase-activity in membranes from endometrial carcinoma

The phosphotyrosine phosphatase (PTPase) decreases the level of phosphotyrosine of intracellular protein substrates, thereby reversing the action of tyrosine phosphorylation to promote cell growth and differentiation. We determined the activities of PTPases in normal and cancerous tissues of the endometrium. The PTPase activity was determined with the synthetic substrate p-nitrophenyl in a spectrophotometric assay. Over 90% of the activity was particulate and the values in proliferative- and secretory-phase endometria and endometrial carcinomas fell within a similar range. This work demonstrates the existence of PTPase activity, counterbalancing the growth-promoting effects of tyrosine kinases, in endometrial carcinoma.