Comparison of the virulence of European and North American genotypes of porcine reproductive and respiratory syndrome virus in experimentally infected pigs

The objective of this study was to compare the virulence of Korean types 1 and 2 porcine reproductive and respiratory syndrome virus (PRRSV) isolated from weaned pigs with respiratory disease. Affected pigs were within the same herd and animals infected with type 2 virus had significantly higher mean rectal temperatures than those with type 1 virus between days 2 and 9 post-inoculation (P<0.05). Similarly, mean serum viral titres, expressed as tissue culture infective doses 50% (TCID50)/mL, as well as macroscopic and microscopic pulmonary lesion scores, were significantly higher at multiple time points in pigs infected with type 2 PRRSV compared to those infected with type 1 virus. Mean numbers of PRRSV-positive cells/unit area of lungs and lymph nodes were also significantly higher in type 2 PRRSV infected pigs. This study demonstrates that type 2 PRRSV is more virulent than type 1 PRRSV in this experimental setting as reflected by the pulmonary pathology induced, the extent of virus distribution, and oral shedding of the virus.

Mitotic exit kinase Dbf2 directly phosphorylates chitin synthase Chs2 to regulate cytokinesis in budding yeast

How cell cycle machinery regulates extracellular matrix (ECM) remodeling during cytokinesis remains poorly understood. In the budding yeast Saccharomyces cerevisiae, the primary septum (PS), a functional equivalent of animal ECM, is synthesized during cytokinesis by the chitin synthase Chs2. Here, we report that Dbf2, a conserved mitotic exit kinase, localizes to the division site after Chs2 and directly phosphorylates Chs2 on several residues, including Ser-217. Both phosphodeficient (chs2-S217A) and phosphomimic (chs2-S217D) mutations cause defects in cytokinesis, suggesting that dynamic phosphorylation-dephosphorylation of Ser-217 is critical for Chs2 function. It is striking that Chs2-S217A constricts asymmetrically with the actomyosin ring (AMR), whereas Chs2-S217D displays little or no constriction and remains highly mobile at the division site. These data suggest that Chs2 phosphorylation by Dbf2 triggers its dissociation from the AMR during the late stage of cytokinesis. Of interest, both chs2-S217A and chs2-S217D mutants are robustly suppressed by increased dosage of Cyk3, a cytokinesis protein that displays Dbf2-dependent localization and also stimulates Chs2-mediated chitin synthesis. Thus Dbf2 regulates PS formation through at least two independent pathways: direct phosphorylation and Cyk3-mediated activation of Chs2. Our study establishes a mechanism for direct cell cycle control of ECM remodeling during cytokinesis.

Measurement of the neutron radius of 208Pb through parity violation in electron scattering

We report the first measurement of the parity-violating asymmetry A(PV) in the elastic scattering of polarized electrons from 208Pb. A(PV) is sensitive to the radius of the neutron distribution (R(n)). The result A(PV)=0.656±0.060(stat)±0.014(syst) ppm corresponds to a difference between the radii of the neutron and proton distributions R(n)-R(p)=0.33(-0.18)(+0.16) fm and provides the first electroweak observation of the neutron skin which is expected in a heavy, neutron-rich nucleus.

New precision limit on the strange vector form factors of the proton

The parity-violating cross-section asymmetry in the elastic scattering of polarized electrons from unpolarized protons has been measured at a four-momentum transfer squared Q2 = 0.624  GeV2 and beam energy E(b) = 3.48  GeV to be A(PV) = -23.80 ± 0.78(stat) ± 0.36(syst) parts per million. This result is consistent with zero contribution of strange quarks to the combination of electric and magnetic form factors G(E)(s) + 0.517G(M)(s) = 0.003 ± 0.010(stat) ± 0.004(syst) ± 0.009(ff), where the third error is due to the limits of precision on the electromagnetic form factors and radiative corrections. With this measurement, the world data on strange contributions to nucleon form factors are seen to be consistent with zero and not more than a few percent of the proton form factors.

Spin-density matrix elements for γp→K*0Σ+ at Eγ=1.85-3.0 GeV with evidence for the κ(800) meson exchange

The exclusive reaction γp→K(+)π(-)Σ(+) was measured for the first time using linearly polarized photons at beam energies from 1.85 to 2.96 GeV. Angular distributions in the rest frame of the K(+)π(-) system were fitted to extract spin-density matrix elements of the K(*0) decay. The measured parity spin asymmetry shows that natural-parity exchange is dominant in this reaction. This result clearly indicates the need for t-channel exchange of the κ(800) scalar meson.

Pathogenesis of Korean type 1 (European genotype) porcine reproductive and respiratory syndrome virus in experimentally infected pigs

The aim of this study was to elucidate the pathogenesis of experimental infection with Korean type 1 porcine reproductive and respiratory syndrome virus (PRRSV) by defining the virus distribution, sites of viral replication, viraemia and gross and microscopical lesions in conventional pigs studied for 28 days after intranasal inoculation. Mean rectal temperature was significantly higher in infected pigs than in negative control pigs at 2 days post inoculation (dpi) (P=0.004), 3 dpi (P<0.001), 4 dpi (P=0.003) and 5 dpi (P=0.034). The log(10)TCID(50)/ml of type 1 PRRSV increased significantly at 0-1 dpi (P=0.024) and 5-7 dpi (P=0.029), but decreased at 10-14 dpi (P=0.026) and 14-21 dpi (P=0.012) in infected pigs. Infected pigs developed multifocal, tan-mottled areas of lung tissue with irregular and indistinct borders. Microscopical lesions, when present, were multifocal, mild to moderate, generally most extensive at 5-7 dpi (P=0.036), and were nearly resolved at 28 dpi. Type 1 PRRSV nucleic acid and antigen were detected exclusively within the cytoplasm of macrophages and type I and II pneumocytes. The score for PRRSV-positive cells increased at 3-7 dpi (P<0.05) and decreased at 10-14 dpi (P=0.034) in infected pigs. Thus, respiratory disease was reproduced in conventional pigs by infection with Korean type 1 PRRSV.

Beam-target double-spin asymmetry A{LT} in charged pion production from deep inelastic scattering on a transversely polarized {3}He target at 1.4<Q{2}<2.7 GeV{2}

We report the first measurement of the double-spin asymmetry A{LT} for charged pion electroproduction in semi-inclusive deep-inelastic electron scattering on a transversely polarized {3}He target. The kinematics focused on the valence quark region, 0.16<x<0.35 with 1.4<Q{2}<2.7  GeV{2}. The corresponding neutron A{LT} asymmetries were extracted from the measured {3}He asymmetries and proton over {3}He cross section ratios using the effective polarization approximation. These new data probe the transverse momentum dependent parton distribution function g{1T}{q} and therefore provide access to quark spin-orbit correlations. Our results indicate a positive azimuthal asymmetry for π{-} production on {3}He and the neutron, while our π{+} asymmetries are consistent with zero.

Synovial fluid CD34⁻ CD44⁺ CD90⁺ mesenchymal stem cell levels are associated with the severity of primary knee osteoarthritis

To the best of our knowledge, no reports have directly compared synovial fluid (SF)- and synovial membrane (SM)-derived mesenchymal stem cells (MSCs) from primary knee osteoarthritis patients in terms of MSC proportion, either immediately after isolation or during culture. Any possible correlation between SM- and SF-MSC purity and osteoarthritis severity, also remains unclear. We therefore assessed quantitative and phenotypic differences in MSCs isolated from SF and SM. We also evaluated the correlation between sample MSC purity, and disease severity, in patients with osteoarthritis. The main result of the current study was that the mean SF-MSC proportion at passage 0 was negatively correlated with Kellgren-Lawrence (KL) grade (r = -0.565, P = 0.002). In addition, KL grade was a only significant independent negative predictor of SF-MSC proportion at passage 0 (β = -0.356, P = 0.039). Conclusively, the proportion of SF-MSCs in fresh samples, evaluated at the single cell level, was inversely correlated with osteoarthritis severity.

Regulation in the targeting of TRAIL receptor 1 to cell surface via GODZ for TRAIL sensitivity in tumor cells

Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) and its receptors, TRAIL-R1 (DR4) and TRAIL-R2 (DR5), promote the selective clearing of various malignancies by inducing apoptosis, holding the promise as a potent therapeutic agent for anticancer. Though DR4 and DR5 have high sequence similarity, differential regulation of both receptors in human tumor cells remains largely unexplored. Here, we repot that golgi-specific Asp-His-His-Cys (DHHC) zinc finger protein (GODZ) regulates TRAIL/DR4-mediated apoptosis. Using the SOS protein recruitment-yeast two-hybrid screening, we isolated GODZ that interacted with the death domain of DR4. GODZ binds to DR4, but not to DR5, through the DHHC and the C-terminal transmembrane domain. Expression level of GODZ affects apoptosis of tumor cells triggered by TRAIL, but not that induced by TNF-α/cycloheximide (CHX) or DNA-damaging drugs. In parallel, GODZ functions to localize DR4 to the plasma membrane (PM) via DHHC motif. Also, introduction of mutation into the cysteine-rich motif of DR4 results in its mistargeting and attenuates TRAIL- or GODZ-mediated apoptosis. Interestingly, GODZ expression is highly downregulated in Hep-3B tumor cells, which show resistance to TRAIL. However, reconstitution of GODZ expression enhances the targeting of DR4 to cell surface and sensitizes Hep-3B cells to TRAIL. Taken together, these data establish that GODZ is a novel DR4-selective regulator responsible for targeting of DR4 to the PM, and thereby for TRAIL-induced apoptosis.

Single spin asymmetries in charged pion production from semi-inclusive deep inelastic scattering on a transversely polarized 3He Target at Q2 = 1.4-2.7 GeV2

We report the first measurement of target single spin asymmetries in the semi-inclusive (3)He(e,e'π(±))X reaction on a transversely polarized target. The experiment, conducted at Jefferson Lab using a 5.9 GeV electron beam, covers a range of 0.16 < x < 0.35 with 1.4 < Q(2) < 2.7 GeV(2). The Collins and Sivers moments were extracted from the azimuthal angular dependence of the measured asymmetries. The π(±) Collins moments for (3)He are consistent with zero, except for the π(+) moment at x = 0.35, which deviates from zero by 2.3σ. While the π(-) Sivers moments are consistent with zero, the π(+) Sivers moments favor negative values. The neutron results were extracted using the nucleon effective polarization and measured cross section ratios of proton to (3)He, and are largely consistent with the predictions of phenomenological fits and quark model calculations.

Mechanics and dynamics of the strain-induced M1-M2 structural phase transition in individual VO₂ nanowires

The elastic properties and structural phase transitions of individual VO(2) nanowires were studied using an in situ push-to-pull microelectromechanical device to realize quantitative tensile analysis in a transmission electron microscope and a synchrotron X-ray microdiffraction beamline. A plateau was detected in the stress-strain curve, signifying superelasticity of the nanowire arising from the M1-M2 structural phase transition. The transition was induced and controlled by uniaxial tension. The transition dynamics were characterized by a one-dimensionally aligned domain structure with pinning and depinning of the domain walls along the nanowire. From the stress-strain dependence the Young's moduli of the VO(2) M1 and M2 phases were estimated to be 128 ± 10 and 156 ± 10 GPa, respectively. Single pinning and depinning events of M1-M2 domain wall were observed in the superelastic regime, allowing for evaluation of the domain wall pinning potential energy. This study demonstrates a new way to investigate nanoscale mechanics and dynamics of structural phase transitions in general.

Evidence that a septin diffusion barrier is dispensable for cytokinesis in budding yeast

Septins are essential for cytokinesis in Saccharomyces cerevisiae, but their precise roles remain elusive. Currently, it is thought that before cytokinesis, the hourglass-shaped septin structure at the mother-bud neck acts as a scaffold for assembly of the actomyosin ring (AMR) and other cytokinesis factors. At the onset of cytokinesis, the septin hourglass splits to form a double ring that sandwiches the AMR and may function as diffusion barriers to restrict diffusible cytokinesis factors to the division site. Here, we show that in cells lacking the septin Cdc10 or the septin-associated protein Bud4, the septins form a ring-like structure at the mother-bud neck that fails to re-arrange into a double ring early in cytokinesis. Strikingly, AMR assembly and constriction, the localization of membrane-trafficking and extracellular-matrix-remodeling factors, cytokinesis, and cell-wall-septum formation all occur efficiently in cdc10Δ and bud4Δ mutants. Thus, diffusion barriers formed by the septin double ring do not appear to be critical for S. cerevisiae cytokinesis. However, an AMR mutation and a septin mutation have synergistic effects on cytokinesis and the localization of cytokinesis proteins, suggesting that tethering to the AMR and a septin diffusion barrier may function redundantly to localize proteins to the division site.

Converting carbohydrates extracted from marine algae into ethanol using various ethanolic Escherichia coli strains

Marine algae, which make up about 80% of the world's living organisms, contain many energy sources, such as sugars and lipids. Therefore, the possibility of utilizing structural carbohydrates from marine algae for bioethanol production has been studied. In order to obtain monosaccharides, Undaria pinnatifida, Chlorella vulgaris, and Chlamydomonas reinhardtii were used for the saccharification experiments. The pretreatment was carried out by dilute acid hydrolysis and enzymatic treatment. To find the optimal conditions, experiments were performed at several temperatures, acid concentrations, pH conditions and durations. To test bioethanol production, several ethanolic E. coli W3110 strains, which were developed previously, were used. The maximum yield of bioethanol, 0.4 g ethanol/g biomass, was achieved with pretreated C. vulgaris and E. coli SJL2526, derived from wild-type E. coli W3110 and which includes the adhB, pdc, galP, and glk genes.

A gene-specific primer extension and liquid bead array system for killer-cell immunoglobulin-like receptor genotyping

A simple and accurate method for killer-cell immunoglobulin-like receptor (KIR) genotyping is developed using KIR gene-specific primer extension (GSPE) followed by bead array hybridization (GSPE method). After amplification of exons 4, 5, and 9, KIR GSPE and bead array hybridization were performed to verify the presence or absence of 16 KIR subfamilies. GSPE method was validated with natural killer/KIR reference panel I consisting of 48 cell types provided by 13th International Histocompatibility Working Group (IHWG) and genomic DNA from 17 peripheral blood cells, 8 cell lines, and 8 buccal cells. The results of reference panel from GSPE method were 100% concordant with the IHWG reference typing information. All genomic DNAs except reference panel were typed for KIR genes with sequence-specific primer methods and showed 100% identical typing results using this novel system. In addition, GSPE method can obtain results in 8 h from DNA with 10 ng genomic DNA in a 96-well-based assay format.

Expression of secreted and membrane-bound mucins in the airways of piglets experimentally infected with Mycoplasma hyopneumoniae

Immunohistochemistry was used to demonstrate secreted mucins MUC2, MUC5AC and MUC5B and membrane-bound mucin MUC4 in the pulmonary bronchioles of piglets experimentally infected with Mycoplasma hyopneumoniae. Conventional status, Landrace-Duroc cross-bred piglets, 13 days of age, were randomised to two groups. One group (n=20) was infected by the intra-tracheal route with the SNU98703 strain of M. hyopneumoniae, and a group of 12 animals acted as uninfected controls. Five infected and three uninfected piglets were euthanased on the day of infection and at 7, 21, and 35 days post-inoculation (PI). Membrane-bound MUC4 and secreted MUC5AC were the predominant mucins produced in the bronchioles of the piglets in response to M. hyopneumoniae infection, but by day 35 PI, all labelled mucins had returned to pre-infection levels, contemporaneous with reduced pulmonary lesion scores. The increased mucin production may result from direct stimulation of the epithelium by mycoplasmal infection, or may arise indirectly following M. hyopneumoniae-induced ciliostasis.

Control of molecular rotors by selection of anchoring sites

We demonstrate a new method to switch on and off the rotational motion of a long-chain molecule by controlling the bonding geometry between the molecule and a substrate. An azobenzene derivative molecule adsorbed on a Au(111) surface is immobile only when its three rotation centers, comprised of two phenyl rings and a nitrogen-nitrogen bond, are located at hollow sites of the Au(111) surface, as observed by scanning tunneling microscopy. Rotational motion can be activated by exciting the vibrational modes and inducing hopping motion away from the immobile site with a voltage pulse.