Expressions of conventional vitellogenin and vitellogenin-like A in worker brains are associated with a nursing task in a ponerine ant.

In eusocial insect colonies, non-reproductive workers often perform different tasks. Tasks of an individual worker are shifted depending on various factors, e.g., age and colony demography. Although a vitellogenin (Vg) gene play regulatory roles in both reproductive and non-reproductive division of labours in a honeybee, it has been shown that the insect Vg underwent multiple gene duplications and sub-functionalisation, especially in apical ant lineages. The regulatory roles of duplicated Vgs were suggested to change evolutionarily among ants, whereas such roles in phylogenetically basal ants remain unclear. Here, we examined the expression patterns of conventional Vg (CVg), Vg-like A, Vg-like B and Vg-like C, as well as Vg receptor, during the task shift in an age-dependent manner and under experimental manipulation of colony demography in a primitive ant Diacamma sp. Expressions of CVg and Vg-like A in a brain were associated with a nursing task. It is suggested that associations of brain expressions of these Vgs with worker tasks were acquired in the basal ant lineage, and that such Vg functions could have sub-functionalised in the derived ant lineage.

Immune-bone interplay in the structural damage in rheumatoid arthritis.

The immune and bone systems maintain homeostasis by interacting closely with each other. Rheumatoid arthritis is a pathological consequence of their interplay, as activated T cell immune responses result in osteoclast-mediated bone erosion. An imbalance between forkhead box protein 3 (Foxp3)+ regulatory T (Treg ) cells and T helper type 17 (Th17) cells is often linked with autoimmune diseases, including arthritis. Th17 cells contribute to the bone destruction in arthritis by up-regulating receptor activator of nuclear factor kappa-Β ligand (RANKL) on synovial fibroblasts as well as inducing local inflammation. Studies on the origin of Th17 cells in inflammation have shed light on the pathogenic conversion of Foxp3+ T cells. Th17 cells converted from Foxp3+ T cells (exFoxp3 Th17 cells) comprise the most potent osteoclastogenic T cell subset in inflammatory bone loss. It has been suggested that osteoclastogenic T cells may have developed originally to stop local infection in periodontitis by inducing tooth loss. In addition, Th17 cells also contribute to the pathogenesis of arthritis by modulating antibody function. Antibodies and immune complexes have attracted considerable attention for their direct role in osteoclastogenesis, and a specific T cell subset in joints was shown to be involved in B cell antibody production. Here we summarize the recent advances in our understanding of the immune-bone interplay in the context of the bone destruction in arthritis.

Direct penetration of spin-triplet superconductivity into a ferromagnet in Au/SrRuO3/Sr2RuO4 junctions.

Efforts have been ongoing to establish superconducting spintronics utilizing ferromagnet/superconductor heterostructures. Previously reported devices are based on spin-singlet superconductors (SSCs), where the spin degree of freedom is lost. Spin-polarized supercurrent induction in ferromagnetic metals (FMs) is achieved even with SSCs, but only with the aid of interfacial complex magnetic structures, which severely affect information imprinted to the electron spin. Use of spin-triplet superconductors (TSCs) with spin-polarizable Cooper pairs potentially overcomes this difficulty and further leads to novel functionalities. Here, we report spin-triplet superconductivity induction into a FM SrRuO3 from a leading TSC candidate Sr2RuO4, by fabricating microscopic devices using an epitaxial SrRuO3/Sr2RuO4 hybrid. The differential conductance, exhibiting Andreev-reflection features with multiple energy scales up to around half tesla, indicates the penetration of superconductivity over a considerable distance of 15 nm across the SrRuO3 layer without help of interfacial complex magnetism. This demonstrates potential utility of FM/TSC devices for superspintronics.

Anomalous switching in Nb/Ru/Sr2RuO4 topological junctions by chiral domain wall motion.

A spontaneous symmetry breaking in a system often results in domain wall formation. The motion of such domain walls is utilized to realize novel devices like racetrack-memories, in which moving ferromagnetic domain walls store and carry information. Superconductors breaking time reversal symmetry can also form domains with degenerate chirality of their superconducting order parameter. Sr2RuO4 is the leading candidate of a chiral p-wave superconductor, expected to be accompanied by chiral domain structure. Here, we present that Nb/Ru/Sr2RuO4 topological superconducting-junctions, with which the phase winding of order parameter can be effectively probed by making use of real-space topology, exhibit unusual switching between higher and lower critical current states. This switching is well explained by chiral-domain-wall dynamics. The switching can be partly controlled by external parameters such as temperature, magnetic field and current. These results open up a possibility to utilize the superconducting chiral domain wall motion for future novel superconducting devices.

Enhanced photon generation in a Nb/n-InGaAs/p-InP superconductor/semiconductor-diode light emitting device.

We experimentally demonstrate Cooper pairs' drastic enhancement of the band-to-band radiative recombination rate in a semiconductor. Electron Cooper pairs injected from a superconducting electrode into an active layer by the proximity effect recombine with holes injected from a p-type electrode. The recombination of a Cooper pair with p-type carriers dramatically increases the photon generation probability of a light-emitting diode in the optical-fiber communication band. The measured radiative decay time rapidly decreases with decreasing temperature below the superconducting transition temperature of the niobium electrodes. Our results indicate the possibility to open up new interdisciplinary fields between superconductivity and optoelectronics.

Dephasing of a superconducting flux qubit.

In order to gain a better understanding of the origin of decoherence in superconducting flux qubits, we have measured the magnetic field dependence of the characteristic energy relaxation time (T(1)) and echo phase relaxation time (T(2)(echo)) near the optimal operating point of a flux qubit. We have measured T(2)(echo) by means of the phase cycling method. At the optimal point, we found the relation T(2)(echo) approximately 2T(1). This means that the echo decay time is limited by the energy relaxation (T(1) process). Moving away from the optimal point, we observe a linear increase of the phase relaxation rate (1/T(2)(echo)) with the applied external magnetic flux. This behavior can be well explained by the influence of magnetic flux noise with a 1/f spectrum on the qubit.

A glycosylated complex of gadolinium, a new potential contrast agent for magnetic resonance angiography?

A new low-molecular weight dendrimer-like MRI contrast agent (Gd-D1) has been synthesized and characterized in vitro by proton and oxygen-17 relaxometry. Its pharmacokinetic parameters and biodistribution patterns were evaluated on rats. Its in vitro and in vivo properties, that is, the longitudinal relaxivity (defined as the increase of the water proton longitudinal relaxation rate induced by one millimole per liter of Gd-D1) equal to 5.6s(-1)mM(-1) at 20 MHz and 310 K, the elimination half-time equal to 85 min, and its low accumulation in liver and spleen, underline its potential as a blood-pool MRI contrast agent.

Parametric control of a superconducting flux qubit.

Parametric control of a superconducting flux qubit has been achieved by using two-frequency microwave pulses. We have observed Rabi oscillations stemming from parametric transitions between the qubit states when the sum of the two microwave frequencies or the difference between them matches the qubit Larmor frequency. We have also observed multiphoton Rabi oscillations corresponding to one- to four-photon resonances by applying single-frequency microwave pulses. The parametric control demonstrated in this work widens the frequency range of microwaves for controlling the qubit and offers a high quality testing ground for exploring nonlinear quantum phenomena of macroscopically distinct states.

Vacuum Rabi oscillations in a macroscopic superconducting qubit oscillator system.

We have observed the coherent exchange of a single energy quantum between a flux qubit and a superconducting LC circuit acting as a quantum harmonic oscillator. The exchange of an energy quantum is known as the vacuum Rabi oscillation: the qubit is oscillating between the excited state and the ground state and the oscillator between the vacuum state and the first excited state. We also show that we can detect the state of the oscillator with the qubit and thereby obtained evidence of level quantization of the LC circuit. Our results support the idea of using oscillators as couplers of solid-state qubits.

Collapse of thermal activation in moderately damped Josephson junctions.

We study switching current statistics in moderately damped Nb-InAs-Nb and intrinsic Bi2Sr2CaCu2O8+delta) Josephson junctions. A paradoxical collapse of thermal activation with increasing temperature is reported and explained by the interplay of two conflicting consequences of thermal fluctuations, which can both assist in premature escape and help in retrapping back into the stationary state. We analyze the influence of dissipation on the thermal escape by tuning damping with a gate voltage, magnetic field, temperature, and an in situ capacitor.

Multiphoton transitions in a macroscopic quantum two-state system.

We have observed multiphoton transitions between two macroscopic quantum-mechanical superposition states formed by two opposite circulating currents in a superconducting loop with three Josephson junctions. Resonant peaks and dips of up to three-photon transitions were observed in spectroscopic measurements when the system was irradiated with a strong rf-photon field. The widths of the multiphoton absorption dips are shown to scale with the Bessel functions in agreement with theoretical predictions derived from the Bloch equation or from a spin-boson model.

Antiviral response by natural killer cells through TRAIL gene induction by IFN-alpha/beta.

Natural killer (NK) cells play an important role in early defense against viral infection. The cytotoxic activity of NK cells is increased by interferon-alpha/beta (IFN-alpha/beta), produced en masse in virally infected cells. However, the mechanism(s) by which IFN-alpha/beta contribute to the NK-cell-mediated antiviral response is not well understood. Here we provide evidence that the cytotoxicity of NK cells is enhanced by IFN-alpha/beta through induction of TNF-related apoptosis-inducing ligand (TRAIL). Isolation and analysis of the murine TRAIL promoter revealed the presence of an IFN-stimulated response element (ISRE), which binds to the transcription factor ISGF3 (interferon stimulated gene factor-3). This promoter is indeed activated by IFN-beta in ISGF3-dependent manner. We also show that virally infected cells, but not uninfected cells, are susceptible to TRAIL-mediated cytotoxicity in vitro, and that the TRAIL expressed in NK cells is indeed crucial in limiting virus replication in vivo. Thus, our study reveals a new molecular link between IFN-alpha/beta signaling and activation of NK cells in antiviral response of the host.

Synthesis of cis- and trans-5,8-dihydroxy-5,6,7,8-tetrahydro-1,4-naphthoquinone.

Cis- and trans-5,8-dihydroxy-5,6,7,8-tetrahydro-1,4-naphthoquinone (1a, 1b) were for the first time synthesized from 5,8-dihydroxy-1,4-naphthoquinone (naphthazazine) (6) as a starting material and racemic triol (3) was first synthesized from 7. The configuration of 1a was determined by X-ray analysis.

T-cell-mediated regulation of osteoclastogenesis by signalling cross-talk between RANKL and IFN-gamma.

Bone resorption is regulated by the immune system, where T-cell expression of RANKL (receptor activator of nuclear factor (NF)-kappaB ligand), a member of the tumour-necrosis factor family that is essential for osteoclastogenesis, may contribute to pathological conditions, such as autoimmune arthritis. However, whether activated T cells maintain bone homeostasis by counterbalancing the action of RANKL remains unknown. Here we show that T-cell production of interferon (IFN)-gamma strongly suppresses osteoclastogenesis by interfering with the RANKL-RANK signalling pathway. IFN-gamma induces rapid degradation of the RANK adapter protein, TRAF6 (tumour necrosis factor receptor-associated factor 6), which results in strong inhibition of the RANKL-induced activation of the transcription factor NF-kappaB and JNK. This inhibition of osteoclastogenesis is rescued by overexpressing TRAF6 in precursor cells, which indicates that TRAF6 is the target critical for the IFN-gamma action. Furthermore, we provide evidence that the accelerated degradation of TRAF6 requires both its ubiquitination, which is initiated by RANKL, and IFN-gamma-induced activation of the ubiquitin-proteasome system. Our study shows that there is cross-talk between the tumour necrosis factor and IFN families of cytokines, through which IFN-gamma provides a negative link between T-cell activation and bone resorption. Our results may offer a therapeutic approach to treat the inflammation-induced tissue breakdown.

CD8(+) T cell-mediated skin disease in mice lacking IRF-2, the transcriptional attenuator of interferon-alpha/beta signaling.

The balanced action of cytokines is known to be critical for the maintenance of homeostatic immune responses. Here, we report the development of an inflammatory skin disease involving CD8(+) T cells, in mice lacking the transcription factor, interferon regulatory factor-2 (IRF-2). CD8(+) T cells exhibit in vitro hyper-responsiveness to antigen stimulation, accompanied with a notable upregulation of the expression of genes induced by interferon-alpha/beta (IFN-alpha/beta). Furthermore, both disease development and CD8(+) T cell abnormality are suppressed by the introduction of nullizygosity to the genes that positively regulate the IFN-alpha/beta signaling pathway. IRF-2 may represent a unique negative regulator, attenuating IFN-alpha/beta-induced gene transcription, which is necessary for balancing the beneficial and harmful effects of IFN-alpha/beta signaling in the immune system.

Overexpression of the csk gene suppresses tumor metastasis in vivo.

The non-receptor tyrosine kinase c-Src has been implicated in the development of numerous human cancers. c-Src is activated in colon cancers, particularly in highly metastatic cells, and its overexpression strongly correlates with tumor progression. C-terminal Src kinase (Csk) has been demonstrated to negatively regulate Src family tyrosine kinases through tyrosine phosphorylation at the C-terminal regulatory site (Tyr-527). We report herein that down-regulation of Src kinase activity by adenovirus-mediated csk gene transfer abrogated the highly metastatic phenotype of colon cancer cells. Overexpression of Csk decreased Src tyrosine kinase activity in NL-17 cells, the highly metastatic clone of mouse colon adenocarcinoma 26. Importantly, Csk overexpression in NL-17 cells resulted in significant suppression of in vivo metastasis, without affecting its tumorgenicity. Csk overexpression decreased the invasiveness of NL-17 cells through Matrigel, in vitro reconstituted basement membrane. Gelatin zymography confirmed the decreased protein levels of MMP-2 (gelatinase A) in the supernatants of Csk-overexpressed NL- 17 cells. These results provide a therapeutic basis for interfering with metastasis of colon cancer by csk gene-mediated down-regulation of Src kinase activity.

A concise and efficient route to 2alpha-(omega-hydroxyalkoxy)-1alpha,25-dihydroxyvi tam in D3: remarkably high affinity to vitamin D receptor.

[reaction: see text]A convenient and potentially valuable synthetic approach to the novel 2alpha-functionalized 1alpha,25-dihydroxyvitamin D3 [1alpha,25(OH)2D3] derivatives (1a-c), which are the C2-epimer of ED-71 and its analogues, has been developed. The C2alpha-modified ring A precursors (1,7-enynes 16, n = 0, 1, and 2) were constructed stereoselectively starting from D-glucose in high yield. In the synthesized 2alpha-(omega-hydroxyalkoxy)-1alpha,25(OH)2D3 derivatives, 1a and 1b showed a greater binding affinity to vitamin D receptor (VDR), up to 1.8 times that of the native hormone.

Involvement of receptor activator of nuclear factor kappaB ligand/osteoclast differentiation factor in osteoclastogenesis from synoviocytes in rheumatoid arthritis.

OBJECTIVE: To clarify the mechanism by which osteoclasts are formed in culture of rheumatoid synoviocytes by exploring the involvement of receptor activator of nuclear factor kappaB ligand (RANKL)/osteoclast differentiation factor (ODF). METHODS: Osteoclast formation was evaluated in cocultures of rheumatoid synovial fibroblasts and peripheral blood mononuclear cells (PBMC) in the presence of macrophage colony stimulating factor and 1,25-dihydroxyvitamin D3 (1,25[OH]2D3) utilizing separating membrane filters. RANKL/ODF expression was examined by Northern blotting in synovial tissues from 5 rheumatoid arthritis (RA) patients and tissues from patients with giant cell tumor (GCT), osteosarcoma (OS), and osteoarthritis (OA). RANKL/ODF expression and the ability of synovial fibroblasts to support osteoclastogenesis were investigated in coculture with PBMC in the presence or absence of 1,25(OH)2D3, and soluble RANKL/ODF and osteoprotegerin (OPG)/osteoclastogenesis inhibitory factor (OCIF) were measured by enzyme-linked immunosorbent assay. The effects of OPG/OCIF on the osteoclastogenesis in the primary culture of rheumatoid synoviocytes and the coculture system were determined. RESULTS: Synovial fibroblasts did not induce osteoclastogenesis when separately cocultured with PBMC. Northern blotting revealed that RANKL/ODF was highly expressed in all tissues from RA and GCT patients, but not from OA or OS patients. Cultured rheumatoid synovial fibroblasts efficiently induced osteoclastogenesis in the presence of 1,25(OH)2D3, which was accompanied by up-regulated expression of RANKL/ODF and decreased production of OPG/OCIF. Osteoclastogenesis from synoviocytes was dose-dependently inhibited by OPG/OCIF. CONCLUSION: RANKL/ODF expressed on synovial fibroblasts is involved in rheumatoid bone destruction by inducing osteoclastogenesis and would therefore be a good therapeutic target.

In vitro and in vivo suppression of osteoclast function by adenovirus vector-induced csk gene.

The proto-oncogene c-src, which encodes a non-receptor-type tyrosine kinase c-Src, has been shown to be essential for osteoclastic bone resorption by the finding that the targeted disruption of the c-src gene induced osteopetrosis in mice. The csk (C-terminal Src family kinase) gene encodes a cytoplasmic protein-tyrosine kinase that specifically phosphorylates the negative regulatory site of c-Src (Tyr-527), thereby inhibiting its kinase activity. To regulate osteoclast function by modulating the kinase activity of c-Src, we constructed an adenovirus vector that carries this gene. The recombinant adenovirus vector carrying csk cDNA induced Csk expression in mouse osteoclast-like cells formed in vitro and clearly reduced c-Src kinase activity in a dose-dependent manner. The expression of Csk caused cytoskeletal disorganization of osteoclast-like cells and strongly suppressed pit-forming activity of the cells in vitro. In addition, the viral vector carrying csk gene dramatically suppressed interleukin-1 alpha-induced bone resorption in vivo. Conversely, kinase-inactive Csk caused an increase in c-Src kinase activity and bone resorbing activity of the cells both in vitro and in vivo, acting as a dominant negative molecule against intrinsic Csk. These findings indicate that the inhibition of c-Src activity by adenovirus vector-mediated csk expression offers an efficient means for inhibiting pathological bone resorption by suppressing osteoclast function.