Elastic cartilage reconstruction by transplantation of cultured hyaline cartilage-derived chondrocytes

Current surgical intervention of craniofacial defects caused by injuries or abnormalities uses reconstructive materials, such as autologous cartilage grafts. Transplantation of autologous tissues, however, places a significant invasiveness on patients, and many efforts have been made for establishing an alternative graft. Recently, we and others have shown the potential use of reconstructed elastic cartilage from ear-derived chondrocytes or progenitors with the unique elastic properties. Here, we examined the differentiation potential of canine joint cartilage-derived chondrocytes into elastic cartilage for expanding the cell sources, such as hyaline cartilage. Articular chondrocytes are isolated from canine joint, cultivated, and compared regarding characteristic differences with auricular chondrocytes, including proliferation rates, gene expression, extracellular matrix production, and cartilage reconstruction capability after transplantation. Canine articular chondrocytes proliferated less robustly than auricular chondrocytes, but there was no significant difference in the amount of sulfated glycosaminoglycan produced from redifferentiated chondrocytes. Furthermore, in vitro expanded and redifferentiated articular chondrocytes have been shown to reconstruct elastic cartilage on transplantation that has histologic characteristics distinct from hyaline cartilage. Taken together, cultured hyaline cartilage-derived chondrocytes are a possible cell source for elastic cartilage reconstruction.

Apoplastic ROS production upon pollination by RbohH and RbohJ in Arabidopsis

Reactive oxygen species (ROS) accumulate at the tip of growing pollen tubes. In Arabidopsis, NADPH oxidases RbohH and RbohJ are localized at the plasma membrane of pollen tube tip and produce ROS in a Ca(2+)-dependent manner. The ROS produced by Rbohs and Ca(2+) presumably play a critical role in the positive feedback regulation that maintains the tip growth. Ultrastructural cytochemical analysis revealed ROS accumulation in the apoplast/cell wall of the pollen grains on the stigmatic papillae in the wild type, but not in the rbohH rbohJ double mutant, suggesting that apoplastic ROS derived from RbohH and RbohJ are involved in pollen tube elongation into the stigmatic papillae by affecting the cell wall metabolism.

Microbunching instability in relativistic electron bunches: direct observations of the microstructures using ultrafast YBCO detectors

Relativistic electron bunches circulating in accelerators are subjected to a dynamical instability leading to microstructures at millimeter to centimeter scale. Although this is a well-known fact, direct experimental observations of the structures, or the field that they emit, remained up to now an open problem. Here, we report the direct, shot-by-shot, time-resolved recording of the shapes (including envelope and carrier) of the pulses of coherent synchrotron radiation that are emitted, and that are a "signature" of the electron bunch microstructure. The experiments are performed on the UVSOR-III storage ring, using electrical field sensitive YBa2Cu3O(7-x) thin-film ultrafast detectors. The observed patterns are subjected to permanent drifts, that can be explained from a reasoning in phase space, using macroparticle simulations.

DAP12 deficiency in liver allografts results in enhanced donor DC migration, augmented effector T cell responses and abrogation of transplant tolerance

Liver interstitial dendritic cells (DC) have been implicated in immune regulation and tolerance induction. We found that the transmembrane immuno-adaptor DNAX-activating protein of 12 kDa (DAP12) negatively regulated conventional liver myeloid (m) DC maturation and their in vivo migratory and T cell allostimulatory ability. Livers were transplanted from C57BL/6(H2(b) ) (B6) WT or DAP12(-/-) mice into WT C3H (H2(k) ) recipients. Donor mDC (H2-K(b+) CD11c(+) ) were quantified in spleens by flow cytometry. Anti-donor T cell reactivity was evaluated by ex vivo carboxyfluorescein diacetate succinimidyl ester-mixed leukocyte reaction and delayed-type hypersensitivity responses, while T effector and regulatory T cells were determined by flow analysis. A threefold to fourfold increase in donor-derived DC was detected in spleens of DAP12(-/-) liver recipients compared with those given WT grafts. Moreover, pro-inflammatory cytokine gene expression in the graft, interferon gamma (IFNγ) production by graft-infiltrating CD8(+) T cells and systemic levels of IFNγ were all elevated significantly in DAP12(-/-) liver recipients. DAP12(-/-) grafts also exhibited reduced incidences of CD4(+) Foxp3(+) cells and enhanced CD8(+) T cell IFNγ secretion in response to donor antigen challenge. Unlike WT grafts, DAP12(-/-) livers failed to induce tolerance and were rejected acutely. Thus, DAP12 expression in liver grafts regulates donor mDC migration to host lymphoid tissue, alloreactive T cell responses and transplant tolerance.

Local Order Refinement in Liquid Lithium Niobate Using a Two Radiation Method (X-Rays and Neutrons)

In the molten LiNbO3 , the local order of the first neighbouring atoms has been described using the total structure factors S(Q) (x) and S(Q)(n) and the total pair correlation functions G(r) (x) and G(r)(n) obtained by X-ray and neutron scattering, respectively. We have also compared the differences [RDF(r)(x) - RDF(r)(n)] of the radial distributions obtained from experiments and computed from the distances in the LiNbO3 crystal. With this refinement it was possible to extract the first pair distances r 1,Nb-o r1, Li-O an r1,O-O whit the high accuracy Δr/r ≈ 0.5%. These values are identical with those in the crystal. Fitting the RDF curves by Gaussian components centred around these distances, the first coordination numbers n 1,Nb-o n1, Li-O and n1,O-O , have been determined with an accuracy Δn/n ≈ 2%. Octahedrally coordinated niobium atoms are present in the melt in the studied range from 1623 K to 1490 K. From these results it is inferred that aggregates built from corner-sharing octahedra, tightened by lithium atoms, are present in the melt.

Raised serum levels of interleukins 6 and 8 and antiphospholipid antibodies in an adult patient with Henoch-Schönlein purpura

BACKGROUND

The long-term prognosis of Henoch-Schönlein purpura (HSP) is determined by the severity of renal involvement, known as HSP nephritis, which varies considerably from patient to patient. There is now increasing evidence that dysregulated cytokine production plays a crucial role in human autoimmune and inflammatory processes.

AIM

To explore the possible contributions of serum antistreptolysin O, C-reactive protein, IgA, interleukin (IL)-6, IL-8, tumour necrosis factor (TNF)-α, anticardiolipin antibody (aCL) and antiphosphatidylserine-prothrombin complex antibody (anti-PSPT) in the pathogenesis of HSP, and to evaluate correlations between those biological parameters and the clinical features.

METHODS

Records were reviewed of 58 patients with HSP who presented initially with palpable purpura between 2003 and 2009. Serum IL-6 levels were determined by chemiluminescent enzyme immunoassay, IL-8 levels by ELISA and TNF-α levels by quantitative sandwich enzyme immunoassay. Serum aCL and anti-PSPT levels were measured according to our previously published procedures.

RESULTS

There was a significant correlation between the serum IL-6 and IgA anti-PSPT levels, and also between the serum IL-8 and IgA anti-PSPT levels. Serum IL-8 and IgA aCL levels were both significantly higher in patients with renal involvement than in those without. Serum IL-6 and IgM anti-PSPT levels were also significantly higher in patients with gastrointestinal symptoms than in those without.

CONCLUSIONS

We suggest that serum IL-6 and IL-8 associated with antiphospholipid antibodies play a pivotal role in the induction of HSP. Based on our results, IL-8 and IgA aCL levels could be useful as markers to monitor the development of HSP nephritis, and IL-6 and IgM anti-PSPT levels could be used as markers to monitor the development of gastrointestinal involvement.

Ca2+-activated reactive oxygen species production by Arabidopsis RbohH and RbohJ is essential for proper pollen tube tip growth

In flowering plants, pollen germinates on the stigma and pollen tubes grow through the style to fertilize the ovules. Enzymatic production of reactive oxygen species (ROS) has been suggested to be involved in pollen tube tip growth. Here, we characterized the function and regulation of the NADPH oxidases RbohH and RbohJ (Respiratory burst oxidase homolog H and J) in pollen tubes in Arabidopsis thaliana. In the rbohH and rbohJ single mutants, pollen tube tip growth was comparable to that of the wild type; however, tip growth was severely impaired in the double mutant. In vivo imaging showed that ROS accumulation in the pollen tube was impaired in the double mutant. Both RbohH and RbohJ, which contain Ca(2+) binding EF-hand motifs, possessed Ca(2+)-induced ROS-producing activity and localized at the plasma membrane of the pollen tube tip. Point mutations in the EF-hand motifs impaired Ca(2+)-induced ROS production and complementation of the double mutant phenotype. We also showed that a protein phosphatase inhibitor enhanced the Ca(2+)-induced ROS-producing activity of RbohH and RbohJ, suggesting their synergistic activation by protein phosphorylation and Ca(2+). Our results suggest that ROS production by RbohH and RbohJ is essential for proper pollen tube tip growth, and furthermore, that Ca(2+)-induced ROS positive feedback regulation is conserved in the polarized cell growth to shape the long tubular cell.

The maturation of HIV-1 protease precursor studied by discrete molecular dynamics

The equilibrium properties of a HIV-1-protease precursor are studied by means of an efficient molecular dynamics scheme, which allows for the simulation of the folding of the protein monomers and their dimerization into an active form and compare them with those of the mature protein. The results of the model provide, with atomic detail, an overall account of several experimental findings, including the NMR conformation of the mature dimer, the calorimetric properties of the system, the effects of the precursor tail on the dimerization constant, the secondary chemical shifts of the monomer, and the paramagnetic relaxation enhancement data associated with the conformations of the precursor. It is found that although the mature protein can dimerize in a unique, single way, the precursor populates several dimeric conformations in which monomers are always native-like, but their binding can be non-native.

On the cellular site of two-pore channel TPC1 action in the Poaceae

The slow vacuolar (SV) channel has been characterized in different dicots by patch-clamp recordings. This channel represents the major cation conductance of the largest organelle in most plant cells. Studies with the tpc1-2 mutant of the model dicot plant Arabidopsis thaliana identified the SV channel as the product of the TPC1 gene. By contrast, research on rice and wheat TPC1 suggested that the monocot gene encodes a plasma membrane calcium-permeable channel. To explore the site of action of grass TPC1 channels, we expressed OsTPC1 from rice (Oryza sativa) and TaTPC1 from wheat (Triticum aestivum) in the background of the Arabidopsis tpc1-2 mutant. Cross-species tpc1 complementation and patch-clamping of vacuoles using Arabidopsis and rice tpc1 null mutants documented that both monocot TPC1 genes were capable of rescuing the SV channel deficit. Vacuoles from wild-type rice but not the tpc1 loss-of-function mutant harbor SV channels exhibiting the hallmark properties of dicot TPC1/SV channels. When expressed in human embryonic kidney (HEK293) cells OsTPC1 was targeted to Lysotracker-Red-positive organelles. The finding that the rice TPC1, just like those from the model plant Arabidopsis and even animal cells, is localized and active in lyso-vacuolar membranes associates this cation channel species with endomembrane function.

EGFR inhibitors augment antitumour helper T-cell responses of HER family-specific immunotherapy

BACKGROUND

Head and neck squamous cell carcinoma (HNSCC) is a major cause of cancer-related morbidity and mortality worldwide. Epidermal growth factor receptor (EGFR)-targeted therapy is an attractive strategy alternative to conventional cancer treatments for HNSCC, but its efficacy remains controversial. T-cell-based immunotherapy has been proposed as a novel therapeutic approach to improve the clinical outcome for HNSCC. In this study, we report human epidermal receptor (HER) family epitopes that induced CD4 T-cell responses to HNSCC. The results provide support for a novel strategy to treat HNSCC by combining EGFR-targeted therapy with T-cell-based immunotherapy.

METHODS

We evaluated the capacity of predicted CD4 T-cell peptide epitopes from EGFR to induce antitumour immune responses in vitro. In addition, EGFR inhibitors were evaluated for their ability to augment tumour MHC class II expression in HNSCC cell lines and subsequently increase T-cell recognition.

RESULTS

Among several predicted peptide epitopes, EGFR875-889 elicited CD4 T-cell responses that were restricted by HLA-DR4, DR15, or DR53 molecules, indicating that the peptide functions as a promiscuous T-cell epitope. The peptide-reactive T cells responded to autologous dendritic cells loaded with EGFR-expressing tumour cell lysates, indicating that these epitopes are naturally processed. In addition, the CD4 T cells were capable of directly recognising and killing HNSCC cells expressing EGFR and the appropriate HLA class II molecule. T cells reactive with the EGFR875-889 epitope could be detected in the blood of HNSCC patients. EGFR875-889-reactive CD4 T cells were also able to recognise several peptide analogues derived from homologous regions of EGFR family members, HER-2, HER-3 and c-MET. Finally, we examined the effects of EGFR tyrosine kinase inhibition or EGFR-blocking antibodies on CD4 T-cell tumour reactivity. Treatment of tumour cells with the EGFR inhibitors enhanced tumour recognition by EGFR875-889-reactive T cells presumably due to the upregulation of HLA-DR expression in the HNSCC cells.

CONCLUSION

We identified novel CD4 T-cell EGFR epitopes and amongst these, EGFR875-889 functions as a promiscuous helper T-cell epitope that can elicit effective antitumour T-cell responses against tumours expressing HER family members and c-MET. These observations should facilitate the translation of T-cell-based immunotherapy into the clinic for the treatment of HNSCC and provide a rational basis for EGFR inhibition, immune-targeted combination therapy.

Experimental study of fusion neutron and proton yields produced by petawatt-laser-irradiated D₂-³He or CD₄-³He clustering gases

We report on experiments in which the Texas Petawatt laser irradiated a mixture of deuterium or deuterated methane clusters and helium-3 gas, generating three types of nuclear fusion reactions: D(d,^{3}He)n, D(d,t)p, and ^{3}He(d,p)^{4}He. We measured the yields of fusion neutrons and protons from these reactions and found them to agree with yields based on a simple cylindrical plasma model using known cross sections and measured plasma parameters. Within our measurement errors, the fusion products were isotropically distributed. Plasma temperatures, important for the cross sections, were determined by two independent methods: (1) deuterium ion time of flight and (2) utilizing the ratio of neutron yield to proton yield from D(d,^{3}He)n and ^{3}He(d,p)^{4}He reactions, respectively. This experiment produced the highest ion temperature ever achieved with laser-irradiated deuterium clusters.

Measurement of the plasma astrophysical S factor for the 3He(d,p)4He reaction in exploding molecular clusters

The plasma astrophysical S factor for the 3He(d,p)4He fusion reaction was measured for the first time at temperatures of few keV, using the interaction of intense ultrafast laser pulses with molecular deuterium clusters mixed with 3He atoms. Different proportions of D2 and 3He or CD4 and 3He were mixed in the gas target in order to allow the measurement of the cross section for the 3He(d,p)4He reaction. The yield of 14.7 MeV protons from the 3He(d,p)4He reaction was measured in order to extract the astrophysical S factor at low energies. Our result is in agreement with other S factor parametrizations found in the literature.

Temperature measurements of fusion plasmas produced by Petawatt-Laser-Irradiated D2 - (3)He or CD4 - (3)He clustering gases

Two different methods have been employed to determine the plasma temperature in a laser-cluster fusion experiment on the Texas Petawatt laser. In the first, the temperature was derived from time-of-flight data of deuterium ions ejected from exploding D(2) or CD(4) clusters. In the second, the temperature was measured from the ratio of the rates of two different nuclear fusion reactions occurring in the plasma at the same time: D(d,(3)He)n and (3)He(d,p)(4)He. The temperatures determined by these two methods agree well, which indicates that (i) the ion energy distribution is not significantly distorted when ions travel in the disassembling plasma; (ii) the kinetic energy of deuterium ions, especially the "hottest part" responsible for nuclear fusion, is well described by a near-Maxwellian distribution.

A low temperature-inducible protein AtSRC2 enhances the ROS-producing activity of NADPH oxidase AtRbohF

Reactive oxygen species (ROS) produced by NADPH oxidases play critical roles in plant environmental responses. Arabidopsis thaliana NADPH oxidase AtRbohF-mediated ROS-production is involved in abiotic stress responses. Because overproduction of ROS is highly toxic to cells, the activity of AtRbohF needs to be tightly regulated in response to diverse stimuli. The ROS-producing activity of AtRbohF is activated by Ca(2+) and protein phosphorylation, but other regulatory factors for AtRbohF are mostly unknown. In this study, we screened for proteins that interact with the N-terminal cytosolic region of AtRbohF by a yeast two-hybrid screen, and isolated AtSRC2, an A. thaliana homolog of SRC2 (soybean gene regulated by cold-2). A co-immunoprecipitation assay revealed that AtSRC2 interacts with the N-terminal region of AtRbohF in plant cells. Intracellular localization of GFP-tagged AtSRC2 was partially overlapped with that of GFP-tagged AtRbohF at the cell periphery. Co-expression of AtSRC2 enhanced the Ca(2+)-dependent ROS-producing activity of AtRbohF in HEK293T cells, but did not affect its phosphorylation-dependent activation. Low-temperature treatment induced expression of the AtSRC2 gene in Arabidopsis roots in proportion to levels of ROS production that was partially dependent on AtRbohF. Our findings suggest that AtSRC2 is a novel activator of Ca(2+)-dependent AtRbohF-mediated ROS production and may play a role in cold responses.

Scale-up Effect in Internal Mixers

In the development of a new polymer and a new compound, mixing equipment plays an important role. However, the properties of a compound tend to vary depending on the size and shape of the equipment used and a means to obtain the same compound by a small scale laboratory mixer as the one obtained by a large scale mixer has been longed for a long time.

As a rubber compound is characterized by the physical properties, they are affected both by the dimensions and shape of the equipment and the mixing conditions. Recently, we developed a laboratory mixer generally following the designs of FH Banbury with exchangeable rotors and mixing chamber blocks which enable us to investigate the influences of the shape of equipment as well as the mixing conditions.

In analysing rubber mixing, we found that the following factors should be taken into account, that is, unit-work which is the applied energy to the unit volume of the material during mixing, Mooney viscosity of the compound, bound rubber which is the amount of polymer unextractable from the compound by a solvent, and weight average molecular weight of polymer extractable by a solvent. If the values of the four factors are close enough for the two compounds obtained by different mixers of different size and shape, one may regard them as the same compounds. Furthermore, we experimentally measured the four factors for the compounds of typical formulations of three species of commercially available rubbers, that is, styrene butadiene rubber, ethylene propylene rubber and butadiene, and expressed the values of the factors as functions of mixing conditions and the parameters of rotor shapes by means of multiple regression analysis. Among the rotor parameters, the following showed significant effects: tip clearance, tip width, total bulkiness and wing overlap ratio. As for the mixing conditions, mixing time, rotor speed and mixing temperature were dominant.

Using the functions obtained by the above mentioned method for the laboratory scale mixer, we tried to find the combinations of rotor shapes and mixing conditions that reproduced the compound mixed by large scale mixers. The optimum parameters of a laboratory mixer for the reproduction of the mixing of an industrial mixer were found to be larger rotor tip clearance, larger rotor tip width, larger wing overlap ratio, higher mixing temperature, and higher rotor speed than those of proportionally reduced dimensions and comparable conditions.

Relationship between Rotor Designs in an Internal Mixer and Physical Properties of Mixed Rubber Compounds

Internal mixers are commonly used for rubber compounding in industry. However, the relations among the designs of equipments, mixing conditions and the properties of the resulting compound are little known. In this paper we tried to reveal some manners of the relations concentrating, particularly, on rotor designs. A specially designed internal mixer (Banbury type) was developed. A number of double winged rotors of various shapes and replaceable mixing chambers were prepared. In developing the equipment, eight parameters were taken into consideration concerning the shape of rotors, that is, lengths, twist angles and overlap ratio of the wings, width and clearance at the rotor tip, angles of flow-in and flow-out at the gap area and total bulkiness of the rotor. Measured properties concerning mixing are: unit work, Mooney viscosity of dumped compound, the amount of bound rubber, weight average molecular weight of the extracted portion of the compound, and peaks in a torque curve, i.e., values of first peak torque and second peak time. In order to estimate the degree of influences of the design parameters mentioned above and mixing conditions, each measured properties were expressed as functions of these parameters by means of multiple regression analysis.

An automated rapid detection system using the quenching probe method for detecting interleukin 28B and inosine triphosphatase single nucleotide polymorphisms in chronic hepatitis C

Single nucleotide polymorphisms (SNPs) in the interleukin 28B gene (IL28B) are good pretreatment predictors of anti-hepatitis C virus (HCV) therapy with interferon. SNPs of the inosine triphosphatase (ITPA) gene are associated with reduced haemoglobin levels during treatment with ribavirin. The i-densy™ (Arkray, Inc.), which is based on the quenching probe (QP) method, automatically detects target genes in blood samples by fluorescence quenching within 100 min. Using a QP and primer set, a gene amplification response is generated that can quickly and easily detect a specific gene's arrangement by fluorometry. The present study was conducted to compare the utility of i-densy (QP method) with that of conventional direct sequencing (DS) for detecting SNPs in the IL28B and ITPA genes in chronic hepatitis C patients. Between June 2011 and January 2012, 73 consecutive patients underwent genotyping of IL28B, and 54 patients underwent genotyping of ITPA. All of the patients were seropositive for HCV-RNA. The IL28B and ITPA genotypes were tested for bi-allelic polymorphisms in rs8099917 (T/T, T/G and G/G; minor allele, G) and rs1127354 (C/C, C/A and A/A; minor allele, A), respectively. The results obtained with the QP method were identical to those obtained with the conventional DS method. The frequency of the IL28B genotypes TT, GT and GG were 74%, 24.7% and 1.4%, respectively, and those of the ITPA genotypes CC, AC and AA were 68.5%, 29.6% and 1.9%, respectively. These results indicate that the i-densy using the QP method can automatically, quickly and easily identify genotypes of IL28B and ITPA.

Modeling Spectroscopic Properties of Ni2+ Ions in the Haldane Gap System Y2BaNiO5

Modeling of spin Hamiltonian parameters enables correlation of crystallographic, spectroscopic, and magnetic data for transition ions in crystals. In this paper, based on the crystallographic data and utilizing the point-charge model and superposition model, the crystal field parameters (CFPs) are estimated for Ni²⁺(3d⁸) ions in the Haldane gap system Y₂BaNiO₅. The CFPs serve as input for the perturbation theory expressions and the crystal field analysis package for microscopic spin Hamiltonian modeling of the zero-field splitting parameters (ZFSPs) D and E. Results of an extensive literature search of the pertinent crystallographic data, experimental ZFSPs, and model parameters are briefly outlined. The modeling aims at verification of the experimental 'single ion anisotropy' parameters and explanation of the controversy concerning the maximal rhombic distortion |E/D| ≈1/3 reported for Ni²⁺ ions in Y₂BaNiO₅. The preliminary results call for reanalysis of some magnetic studies of the Haldane gap systems.

Far-infrared optical conductivity of CeCu2Si2

We investigated the optical reflectivity of the heavy-fermion metal CeCu(2)Si(2) in the energy range 3 meV-30 eV for temperatures between 4 and 300 K. The results for the charge dynamics indicate a behavior that is expected for the formation of a coherent heavy quasiparticle state: upon cooling the spectra of the optical conductivity indicate a narrowing of the coherent response. Below temperatures of 30 K a considerable suppression of conductivity evolves below a peak structure at 13 meV. We assign this gap-like feature to strong electron correlations due to the 4f-conduction electron hybridization.

Optical study of archetypical valence-fluctuating Eu systems

We have investigated the optical conductivity of the prominent valence-fluctuating compounds EuIr(2)Si(2) and EuNi(2)P(2) in the infrared energy range to get new insights into the electronic properties of valence-fluctuating systems. For both compounds, we observe upon cooling the formation of a renormalized Drude response, a partial suppression of the optical conductivity below 100 meV, and the appearance of a midinfrared peak at 0.15 eV for EuIr(2)Si(2) and 0.13 eV for EuNi(2)P(2). Most remarkably, our results show a strong similarity with the optical spectra reported for many Ce- or Yb-based heavy-fermion metals and intermediate valence systems, although the phase diagrams and the temperature dependence of the valence differ strongly between Eu systems and Ce- or Yb-based systems. This suggests that the hybridization between 4f and conduction electrons, which is responsible for the properties of Ce and Yb systems, plays an important role in valence-fluctuating Eu systems.

Propeptide processing and proteolytic activity of proenzymes of the staphylococcal and enterococcal GluV8-family protease

Proenzymes with various lengths of propeptides have been observed in GluV8 from Staphylococcus aureus and GluSE from S. epidermidis. However, the production mechanism of these proenzymes and roles of truncated propeptides have yet to be elucidated. Here we demonstrate that shortening of propeptide commonly occurs in an auto-catalytic manner in GluV8-family members, including those from coagulase negative Staphylococci and Enterococcus faecalis. Accompanied with propeptide shortening, the pro-mature junction (Asn/Ser_1-Val1) becomes more susceptible towards the hetero-catalytic maturation enzymes. The auto-catalytic propeptide truncation is not observed in Ser169Ala inert molecules of GluV8-family members. A faint proteolytic activity of proenzymes from Staphylococcus caprae and E. faecalis is detected. In addition, proteolytic activity of proenzyme of GluV8 carrying Arg-3AlaAsn.1 is demonstrated with synthetic peptide substrates LLE/Q-MCA. These results suggest that GluV8-family proenzymes with shortened propeptides intrinsically possess proteolytic activity and are involved in the propeptide shortening that facilitates the final hetero-catalytic maturation.

Atomic and electronic structure of ultrathin Bi(111) films grown on Bi2Te3(111) substrates: evidence for a strain-induced topological phase transition

We studied the atomic and electronic structures of ultrathin Bi(111) films grown on Bi(2)Te(3) by means of angle-resolved photoemission, first-principles calculations, and low-energy electron diffraction. These Bi films were found to be strained due to the influence of the substrate. Accordingly, the band structure is affected and Bi undergoes a topological phase transition; it is shown that the Z(2) topological invariant in three dimensions switches from +1 (trivial) to -1 (nontrivial or topological). This was clearly confirmed from the change in the surface-state dispersion near the Fermi level. Our discovery offers a method to produce novel topological systems from simple materials.

Thermodynamics of strongly allosteric inhibition: a model study of HIV-1 protease

Protein inhibitors that shift the thermodynamic equilibrium towards a denatured state escape, in general, the straightforward framework of competitive or allosteric inhibitors. The equilibrium properties of peptides which compete with the folding, or more precisely destabilize the native state, of the human immunodeficiency virus (HIV)-1 protease monomer are studied within a structure-based model. The effect of peptides that disrupt the hydrophobic core of the protein can still be summarized in terms of an inhibition constant, which depends on the thermal stability of the protein. The state of the protein denatured by such a peptide is more structured than its intrinsic denatured state, but displays the same degree of compactness. Peptides that target less buried regions of the protein are less efficient and display a more complex thermodynamics that cannot be captured in a simple way.

Localization of connectin-like proteins in leg and flight muscles of insects

In leg muscle sarcomeres of a beetle, approximately 6 mum sarcomere length at rest, projectin ( approximately 1200 kDa) was located on the myosin filament up to 2 mum from the both ends of the filament, using immunofluorescence and immunoelectron microscopy. On the other hand, projectin linked the Z line to the myosin filament and bound on the myosin filament in beetle flight muscle, approximately 3-4 mum sarcomere length at rest. Connectin-like protein ( approximately 3000 kDa) was detected by immunoblot tests in beetle, bumblebee and waterbug leg muscles. Immunofluorescence and immunoelectron microscopic observations revealed that the connectin-like protein linked the myosin filament to the Z line in beetle leg muscle.

A 7.5-kb 3'-Terminal cDNA Sequence of Chicken Skeletal Muscle Nebulin Reveals Its Actin Binding Regions

Nebulin is an approximately 700 kDa filamentous protein in vertebrate skeletal muscle. It binds to the Z line and also binds side-by-side to the entire thin (actin) filament in a sarcomere. Nebulin is currently thought to be a molecular ruler regulating the length of the thin filament to 1 mum. The complete sequence of human skeletal muscle nebulin was determined by . Because of its large size, only fragmental sequence information has been available for nebulins other than human skeletal muscle. This paper describes for the first time the sequence of about one third (C terminal region) of chicken skeletal muscle nebulin. It was found that the fundamental structure of human nebulin, consisting of 35 amino acid repeats (modules) plus C terminal serine-rich and SH3 domains linked to the Z line are well conserved with chicken nebulin. Sequence identity ranged from 74 to 91%. There were super-repeats (seven modules), a first linker repeat, simple repeat and a second linker repeat in addition to the Z line binding region as in human nebulin. However, there were 2 fewer modules in the first linker repeat and 6 fewer in the simple repeat in chicken nebulin as compared to human nebulin. Two isoforms of chicken nebulin were sequenced indicating insertion of approximately 6 or 11 modules to a structure similar to that of human nebulin. Recombinant first linker repeats M51 approximately 56 were shown to bind to actin using the ELISA technique as well as human nebulin recombinants.