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A two-dimensional magnetic network, [Co(cis-CHDA)(μ2-H2O)(H2O)2]·2H2O (1), featuring one-dimensional water-bridged Co2+ chains that are linked by pure cis-1,4-cyclohexanedicarboxylate (cis-CHDA) bridges has been obtained. Magnetic studies show that 1 exhibits spin-canted antiferromagnetism with spin-glass behavior at low temperature.

A novel alcoholism model which involves impact of Twitter is formulated. It is shown that the model has multiple equilibria. Stability of all the equilibria are obtained in terms of the basic reproductive number R0. Using the center manifold theory, the occurrence of backward and forward bifurcation for a certain defined range of R0 are established. Furthermore, the existence of Hopf bifurcation is also established by regarding the transmission coefficient β as the bifurcation parameter. Numerical simulations and sensitivity analysis on a few parameters are also carried out. Our results show that Twitter can serve as a good indicator of alcoholism model and affect the spread of the drinking.

A recoilless gun is a kind of weapon equipment for individual soldier and its back blast flow has certain influence on the shooter during the launch process. In order to study the launch safety of a recoilless gun firing in a finite space of 2.5×2.5×2m, numerical simulation of the back blast flow field was carried out based on the three-dimensional unsteady viscous compressible N-S equations. The result shows that a complex reflected shock wave is formed due to the reflection of the wall behind the nozzle. The reflected shock wave represents reciprocating motion in the finite space and its intensity is much higher than that of the initial shock wave. Critical damage will be imposed on the shooter if no safeguard procedure is adopted. The high temperature gas flow may ignite the inflammable gases in the finite space and cause secondary damage. The research results are significant for understanding the characteristics of the back blast flow of the recoilless gun launching in the finite space, predicting and taking effective action to reduce the damage on the shooter.

This paper is concerned with the analytical solution to lateral equivalent flexural rigidity for fiber-reinforced top-hat stiffened composite plate subjected to pure bending. The plate is divided into three parts consist of single-laminate, double-laminate and hat-laminate. After computing equivalent flexural rigidity of the three parts respectively, the overall rigidity is calculated based on the equality of relative rotation angle. An example has been adopted for analytical calculation and then been modeled by finite elements method. A comparison was made to verify the validity of analytical method.

Statics is set up on the basis of 4 axioms of statics. Although these axioms are distillate and summarizing of the accumulated humankind's experience in long-range production and life, introduction of these axioms to statics seems a bit abrupt, especially the critical axiom "resultant of two forces" far fetched. This article was an attempt to present the embodying description of the effect of force and force system, based on the nature of effect of force and the equivalent and equilibrium of force systems. On this basis, theorem of two forces resultant and the theorem of two forces balance were proved, and the theorem of force systems equivalent was brought up. A new framework of static equilibrium system was built up to try to make a more perfect and more reasonable description for static equilibrium.

Two novel syntheses of the flavone luteolin are described. In the first, 3,5-dimethoxyphenol was converted to 2-hydroxy-4,6-dimethoxyacetophenone and then by condensation with 3,4-dimethoxybenzaldehyde to 2′-hydroxy-3,4,4′,6′-tetramethoxychalcone. In the second, the chalcone step was prepared in which 3,5-dimethoxyphenol was acylated with 3,4-dimethoxycinnamoyl chloride. The chalcone was then cyclised with iodine and demethylated with pyridine hydrochloride to form luteolin in 47% and 40% overall yield, respectively. Several disadvantages of previous syntheses like long reaction time, harsh reaction conditions and low overall yield have been overcome.

Two routes for the synthesis of the flavanone naringenin are described. In the first, 3,5-dimethoxyphenol is converted to 2-hydroxy-4,6-dimethoxyacetophenone and then by condensation with anisaldehyde to 2′-hydroxy-4,4′,6′-trimethoxychalcone. The chalcone is then cyclised with aqueous hydrochloric acid and demethylated with pyridine hydrochloride to form naringenin in 45% overall yield. The condensation of 2-hydroxy-4,6-dimethoxyacetophenone with anisaldehyde could also directly produce 4′,5,7-trimethoxyflavanone, which was then converted into naringenin in 60% overall yield. In the second route, a single step for the preparation of the chalcone is used in which 1,3,5-trimethoxybenzene is acylated with p-methoxycinnamic acid. Although the synthesis of naringenin is achieved in a lower overall yield of 29%, the process is simpler.

Based on the features of steel plate with a rectangular cut out bonded by composite patch, a three-dimensional mechanical model for stiffness analysis was developed. The relative stiffness of steel plate with a rectangular cutout before and after bonded composite patches versus intact plate is introduced and investigated. The results indicate that the relative stiffness of the patched plate increases with the patch thickness increasing, but the performance can not be effectively improved depending upon adding patch thickness alone, when patch thickness is more than five layers. The analytical solutions, when patch more than the 4 layers, are in good agreement with the finite element simulations.

An ANSYS-based "volume-spring-plate" three-dimensional finite element model is established in this paper to analyze steel plate with a rectangular hole reinforced by double-side bonding patch, in which the plate is simulated by solid45 8-node 3D element, the adhesive layer is simulated by linear elastic spring element combin14, and the patch is simulated by shell element. Relative intensity, relative stiffness and yield load rising rate of a patched steel plate with regard to parameters, such as the patch length, width, the number of patch layer and ply orientation are studied. The results indicate that composite bonded repair can effectively restore the mechanical properties of the structure and improve the service life.

The numerical simulation of the static response of viscoelastic materials with the finite element method is presented in this paper. In particular, elastomeric solids which are of essential engineering interest are discussed. A rubbery elastic manner is assumed to be modeled with an Ogden-type strain energy function. A Prony series represents the relaxation moduli is exploited. By using a general finite element software ANSYS, numerical examples illustrate relaxation and creeping phenomena.

The failure mode of steel plate with a center elliptic corroding hole double-sided adhesively bonded by carbon fiber composite patch is identified and studied, and analytical solution to load-carrying capacity of damaged steel plate bonded by composite patch is presented in this paper. Ultimate load of patched steel plate corresponding to each failure mode is derived and calculated respectively, the load carrying capacity of the patched plate is equal to the minimum value of these calculations. Yielding load when yielding occurs near the hole-edge of repaired structure from present method was compared to the results of ANSYS FEA, and the ultimate load of repaired plate from present method was compared to the test results. Results indicate: Repaired by bonded composite patch, static strength and loading carrying capacity of damaged steel plate or structures can be effectively restored. Yielding load and ultimate load of patched steel plate is visibly increased. The present analytical results have a good agreement with FEA and experimental results.

Vibration mode of the constrained damping cantilever is built up according to the mode superposition of the elastic cantilever beam. The control equation of the constrained damping cantilever beam is then derived using Lagrange’s equation. Dynamic response of the constrained damping cantilever beam is obtained according to the principle of virtual work, when the concentrated force is suddenly unloaded. Frequencies and transient response of a series of constrained damping cantilever beams are calculated and tested. Influence of parameters of the damping layer on the response time is analyzed. Analyitcal and experimental approaches are used for verification. The results show that the method is reliable.

Animals capable of regenerating multiple tissue types, organs, and appendages after injury are common yet sporadic and include some sponge, hydra, planarian, and salamander (i.e., newt and axolotl) species, but notably such regenerative capacity is rare in mammals. The adult MRL mouse strain is a rare exception to the rule that mammals do not regenerate appendage tissue. Certain commonalities, such as blastema formation and basement membrane breakdown at the wound site, suggest that MRL mice may share other features with classical regenerators. As reported here, MRL fibroblast-like cells have a distinct cell-cycle (G2/M accumulation) phenotype and a heightened basal and wound site DNA damage/repair response that is also common to classical regenerators and mammalian embryonic stem cells. Additionally, a neutral and alkaline comet assay displayed a persistent level of intrinsic DNA damage in cells derived from the MRL mouse. Similar to mouse ES cells, the p53-target p21 was not expressed in MRL ear fibroblasts. Because the p53/p21 axis plays a central role in the DNA damage response and cell cycle control, we directly tested the hypothesis that p21 down-regulation could functionally induce a regenerative response in an appendage of an otherwise nonregenerating mouse strain. Using the ear hole closure phenotype, a genetically mapped and reliable quantitative indicator of regeneration in the MRL mouse, we show that the unrelated Cdkn1a tmi/Tyj /J p21 −/− mouse (unlike the B6129SF2/J WT control) closes ear holes similar to MRL mice, providing a firm link between cell cycle checkpoint control and tissue regeneration.

MRL mice display unusual healing properties. When MRL ear pinnae are hole punched, the holes close completely without scarring, with regrowth of cartilage and reappearance of both hair follicles and sebaceous glands. Studies using (MRL/lpr x C57BL/6)F(2) and backcross mice first showed that this phenomenon was genetically determined and that multiple loci contributed to this quantitative trait. The lpr mutation itself, however, was not one of them. In the present study we examined the genetic basis of healing in the Large (LG/J) mouse strain, a parent of the MRL mouse and a strain that shows the same healing phenotype. LG/J mice were crossed with Small (SM/J) mice and the F(2) population was scored for healing and their genotypes determined at more than 200 polymorphic markers. As we previously observed for MRL and (MRL x B6)F(2) mice, the wound-healing phenotype was sexually dimorphic, with female mice healing more quickly and more completely than male mice. We found quantitative trait loci (QTLs) on chromosomes (Chrs) 9, 10, 11, and 15. The heal QTLs on Chrs 11 and 15 were linked to differential healing primarily in male animals, whereas QTLs on Chrs 9 and 10 were not sexually dimorphic. A comparison of loci identified in previous crosses with those in the present report using LG/J x SM/J showed that loci on Chrs 9, 11, and 15 colocalized with those seen in previous MRL crosses, whereas the locus on Chr 10 was not seen before and is contributed by SM/J.

The MRL/MpJ mouse is an inbred laboratory strain of Mus musculus, known to exhibit enhanced autoimmunity, increased wound healing, and increased regeneration properties. We report the full-length mitochondrial DNA (mtDNA) sequence of the MRL mouse (Accession # EU450583), and characterize the discovery of two naturally occurring heteroplasmic sites. The first is a T3900C substitution in the TPsiC loop of the tRNA methionine gene (tRNA-Met; mt-Tm). The second is a heteroplasmic insertion of 1-6 adenine nucleotides in the A-tract of the tRNA arginine gene (tRNA-Arg; mt-Tr) at positions 9821-9826. The level of heteroplasmy varied independently at these two sites in MRL individuals. The length of the tRNA-Arg A-tract increased with age, but heteroplasmy at the tRNA-Met site did not change with age. The finding of naturally occurring mtDNA heteroplasmy in an inbred strain of mouse makes the MRL mouse a powerful new experimental model for studies designed to explore therapeutic measures to alter the cellular burden of heteroplasmy.

The apolipoprotein E (ApoE) gene has been linked to maladies such as hypercholesterolemia, CNS injury and disease. In this study, we present evidence that, in addition to the known transcript (ApoE S1) that translates into ApoE, there are three additional transcripts in mice. Two of these transcripts, ApoE S2 and ApoE S3, which are predicted to be transmembrane proteins, are transcribed from the sense strand. ApoE AS1 is transcribed from the antisense strand and is complementary to exon 4 of ApoE S1. The open reading frame of ApoE AS1 is conserved between human and mouse. The antisense transcript falls within the region of the human epsilon 4 allele that has been linked to the familial onset form of Alzheimer's disease. We also demonstrate the expression of ApoE S3 and ApoE AS1 in ApoE knockout mice, and ApoE S1 and ApoE S2 do not get transcribed. We had previously identified ApoE S1 as being upregulated in mice after spinal cord injury. In this study, we show that in spinal cord-injured C57BL/6 mice, both ApoE S1 and ApoE S3 transcripts are 10-fold upregulated and the antisense ApoE AS1 is 100-fold upregulated compared with normal levels. Such data suggest that these alternate transcripts are involved in the molecular pathogenesis of CNS disease and perhaps in ApoE expression in general, as we show that ApoE S2 and AS1 are also transcribed in human.

Endosomal trafficking is regulated by the recruitment of effector proteins to phosphatidylinositol 3-phosphate [PtdIns(3)P] on early endosomes. At the plasma membrane, phosphatidylinositol-(3,4)-bisphosphate [PtdIns(3,4)P2] binds the pleckstrin homology (PH) domain-containing proteins Akt and TAPP1. Type Iα inositol polyphosphate 4-phosphatase (4-phosphatase) dephosphorylates PtdIns(3,4)P2, forming PtdIns(3)P, but its subcellular localization is unknown. We report here in quiescent cells, the 4-phosphatase colocalized with early and recycling endosomes. On growth factor stimulation, 4-phosphatase endosomal localization persisted, but in addition the 4-phosphatase localized at the plasma membrane. Overexpression of the 4-phosphatase in serum-stimulated cells increased cellular PtdIns(3)P levels and prevented wortmannin-induced endosomal dilatation. Furthermore, mouse embryonic fibroblasts from homozygous Weeble mice, which have a mutation in the type I 4-phosphatase, exhibited dilated early endosomes. 4-Phosphatase translocation to the plasma membrane upon growth factor stimulation inhibited the recruitment of the TAPP1 PH domain. The 4-phosphatase contains C2 domains, which bound PtdIns(3,4)P2, and C2-domain-deletion mutants lost PtdIns(3,4)P24-phosphatase activity, did not localize to endosomes or inhibit TAPP1 PH domain membrane recruitment. The 4-phosphatase therefore both generates and terminates phosphoinositide 3-kinase signals at distinct subcellular locations.

Three new triterpenoids, (3beta,8beta,14alpha,21alpha)-26,27-dinoronocerane-3,8,14,21-tetrol (1), (3beta,8beta,14alpha,21beta)-26,27-dinoronocerane-3,8,14,21-tetrol (2). and lycopodiin A (3), together with four known compounds, lycoclavanol (4), lycoclaninol (5), alpha-onocerin (6). and 3-epilycoclavanol (7). were isolated from Lycopodium japonicum THUNB (Lycopodiaceae). Their structures were established by means of spectroscopic analyses. Compounds 3 and 7 showed moderate antitumor activity. Compounds 4 and 6 exhibited acctylcholinestcrase inhibition activity.

The MRL mouse has been shown to display an epimorphic regenerative response after ear hole punching leading to complete closure within 30 days and cartilage regrowth. The regenerative capacity of the MRL has also been seen after a severe cryoinjury to the heart leads to complete healing without scarring and functional myocardium. The wound healing ear hole closure response that occurs in MRL mice has been shown to be genetically controlled. We have previously identified 11 quantitative trait loci (QTL) that govern healing in an intercross of (MRL x C57BL/6 J) mice. However, it is desirable to use another poorly healing mouse strain to elucidate the full range of genetic factors that affect this important process. In the current study, we have used an inbred subspecies of the mouse, M. castaneus, and have confirmed a number of loci identified previously. In addition, we report three new healing QTL. Furthermore, in this strain combination, we note a strong sexual dimorphism also observed in the MRL x C57BL/6 cross, both in the healing trait and in the QTL that control it.

Herpes simplex keratitis (HSK) is an inflammatory response to viral infection and self antigens in the cornea and is a major cause of blindness. Using two strains of mice which are susceptible (129/SVEV) and resistant (C57BL/6) to herpes simplex virus (HSV) strain KOS, (129/SVEV × C57BL/6)F2mice were generated and examined for their disease susceptibility in terms of clinical symptoms, ocular disease, and antibody production following corneal scarification with HSV (KOS). A genome-wide screen was carried out using microsatellite markers to determine the genetic loci involved in this response. Loci on chromosomes 4, 5, 12, 13, and 14 were shown to be involved in general susceptibility to clinical disease, whereas loci on chromosomes 10 and 17 were shown to be unique to ocular disease.

The Golli-MBP transcription unit contains three Golli-specific exons as well as the seven exons of the classical myelin basic protein (MBP) gene and encodes alternatively spliced proteins that share amino acid sequence with MBP. Unlike MBP, which is a late Ag expressed only in the nervous system, Golli exon-containing gene products are expressed both pre- and postnatally at many sites, including lymphoid tissue, as well as in the central nervous system. To investigate whether Golli-MBP peptides unique to Golli would result in neurological disease, we immunized rats and observed a novel neurological disease characterized by mild paralysis and the presence of groups of lymphocytes in the subarachnoid space but not in the parenchyma of the brain. Disease was induced by Th1-type T cells that displayed an unusual activation phenotype. Primary stimulation in vitro induced T cell proliferation with increased surface CD45RC that did not become down-regulated as it did in other Ag-stimulated cultures. Secondary stimulation of this CD45RChigh population with Ag, however, did not induce proliferation or IL-2 production, although an IFN-γ-producing population resulted. Proliferation could be induced by secondary stimulation with IL-2 or PMA-ionomycin, suggesting an anergic T cell population. Cells could adoptively transfer disease after secondary stimulation with IL-2, but not with Ag alone. These responses are suggestive of a chronically stimulated, anergic population that can be transiently activated to cause disease, fall back into an anergic state, and reactivated to cause disease again. Such a scenario may be important in chronic human disease.

Wound healing of mammalian tissue is an essential process in the maintenance of body integrity. The general mechanism of wound healing usually studied in adult mammals is repair, in contrast to the regeneration seen in more primitive vertebrates. We recently have discovered that MRL/MpJ mice, unlike all other strains of mice tested, undergo rapid and complete wound closure that resembles regeneration. Specifically, through-and-through surgical ear hole wounds close without scarring in Fas lpr × C57BL/6)F2 and backcross populations. In the primary screens of these populations, quantitative trait loci that control the extent of wound closure were detected on chromosomes 8, 12, and 15 and at two separate locations on chromosome 13. Evidence of further genetic control of healing was found on chromosome 7. All alleles that contribute to full wound closure are derived from the MRL/MpJ- Fas lpr parent except for the quantitative trait locus on chromosome 8, which is derived from C57BL/6.

Mouse strains C57BL/6 (B6) and MRL were studied by whole mouse genome chip microarray analyses of RNA isolated from amputation sites at different times pre- and postamputation at the midsecond phalange of the middle digit. Many keratin genes were highly differentially expressed. All keratin genes were placed into three temporal response classes determined by injury/preinjury ratios. One class, containing only Krt6 and Krt16, were uniquely expressed relative to the other two classes and exhibited different temporal responses in MRL vs. B6. Immunohistochemical staining for Krt6 and Krt16 in tissue sections, including normal digit, flank skin, and small intestine, and from normal and injured ear pinna tissue exhibited staining differences in B6 (low) and MRL (high) that were consistent with the microarray results. Krt10 staining showed no injury-induced differences, consistent with microarray expression. We analyzed Krt6 and Krt16 gene association networks and observed in uninjured tissue several genes with higher expression levels in MRL, but not B6, that were associated with the keratinocyte activated state: Krt6, Krt16, S100a8, S100a9, and Il1b; these data suggest that keratinocytes in the MRL strain, but not in B6, are in an activated state prior to wounding. These expression levels decreased in MRL at all times postwounding but rose in the B6, peaking at day 3. Other keratins significantly expressed in the normal basal keratinocyte state showed no significant strain differences. These data suggest that normal MRL skin is in a keratinocyte activated state, which may provide it with superior responses to wounding.

In order to define the receptor binding site and the structure-functional relationship of tumor necrosis factor (TNF), single amino acid substitutions were made by site-directed mutagenesis at selected residues of human tumor necrosis factor, using a phagemid mutagenesis/expression vector. The recombinant TNF mutants were compared to the wild type TNF in assays using crude bacterial lysates, for protein yield, solubility, subunit trimerization, receptor binding inhibition activity, and in vitro cytotoxic activity. All mutants which did not form cross-linkable trimer also showed little cytotoxic activity or receptor binding inhibition activity, indicating that trimer formation is obligatory for TNF-alpha activity. Most mutations of internal residues yielded no cross-linkable trimer, while most mutations of surface residues yielded cross-linkable trimer. Mutations at surface residues Leu29, Arg31, and Ala35 yielded cross-linkable trimers with good activities, except proline substitutions which may cause conformational changes in the polypeptide chain. This suggested that these residues are near the receptor binding site. Mutations at other strictly conserved internal residues such as Ser60, His78, and Tyr119 form cross-linkable trimer with little activity. These mutations may indirectly affect the receptor binding site by forming trimers with undetectable abnormalities. Mutants of surface residues Tyr87, Ser95, Ser133, and Ser147 affect receptor binding and cytotoxic activity but not trimer formation, suggesting that these residues are involved directly in receptor binding. The fact that residues Arg31, Ala35, Tyr87, Ser95, and Ser147, located on the opposite sides of a monomer, are clustered at the intersubunit grooves of TNF trimer supports the current notion that TNF receptor binding sites are trivalent and are located at the three intersubunit grooves. However, our finding that Ser133, which is outside the groove, can also be involved directly in receptor binding suggested that the receptor binding sites of TNF may not be confined to the intersubunit grooves, but extended to include additional surface residues.

Retinal S-antigen is widely used to study the LEW rat model of experimental autoimmune uveoretinitis (EAU). In this report, we have examined the T cell receptor V gene usage of several T cell lines recognizing either pathogenic or nonpathogenic sites on S-antigen to determine whether the V alpha 510 and V beta 510 rat homologues of the murine V alpha 2 and V beta 8 families, respectively, are used by uveitogenic T cells. Using cDNA probes for a LEW rat T cell receptor specific for the encephalitogenic determinant of myelin basic protein, we have found that in the retinal S-antigen/EAU model for autoimmune disease, pathogenicity correlates with usage of those rat V genes. Thus, all of the pathogenic lines were found to express T cell receptors of the V beta 510 and V alpha 510 families; conversely, V beta 510 usage was not detected in any of the nonpathogenic lines. Usage of these V regions has been associated with pathogenicity in the murine and rat models of experimental autoimmune encephalomyelitis, and now with S-antigen-induced EAU.

Superparamagnetic microspheres with an Fe3O4@SiO2 core and a perpendicularly aligned mesoporous SiO2 shell were synthesized through a surfactant-templating sol−gel approach. The microspheres possess high magnetization (53.3 emu/g), high surface area (365 m2/g), large pore volume (0.29 cm3/g), and uniform mesopore (2.3 nm). By using the unique core−shell microspheres with accessible large pores and excellent magnetic property, a fast removal of microcystins with high efficiency (>95%) can be achieved.

A new lupane acid, 2 beta-carboxyl, 3 beta-hydroxyl-norlupA (1)-20 (29)-en-28-oic acid (1), together with five known lupane acid derivatives (2-6), were isolated from the stings of Gleditsia sinensis Lam.. Their structures were elucidated on the basis of 1D and 2D NMR techniques. All these known compounds were isolated from this genus for the first time. The new compound 1 showed strong anti-HIV activity.

Ypt/Rabs are Ras-related GTPases that function as key regulators of intracellular vesicular trafficking. Their slow intrinsic rates of GTP hydrolysis are catalyzed by GTPase-activating proteins (GAPs). Ypt/Rab-GAPs constitute a family of proteins that contain a TBC (Tre-2/Bub2/Cdc16) domain. Only three of the 51 family members predicted in the human genome are confirmed Ypt/Rab-GAPs. Here, we report the identification and characterization of a novel mammalian Ypt/Rab-GAP, TBC domain family, member 15 (TBC1D15). TBC1D15 is ubiquitously expressed and localized predominantly to the cytosol. The TBC domain of TBC1D15 exhibits relatively high homology with that of Gyp7p, a yeast Ypt/Rab-GAP. Furthermore, TBC1D15 stimulates the intrinsic GTPase activity of Rab7, and to a lesser extent Rab11, but is essentially inactive towards Rab4 or Rab6. These data increase the number of mammalian TBC domain family members with demonstrated Rab-GAP activity to four, and suggest that TBC1D15 may be involved in Rab7-mediated late endosomal trafficking.

Three new triterpenoids, (3beta,8beta,14alpha,21alpha)-26,27-dinoronocerane-3,8,14,21-tetrol (1), (3beta,8beta,14alpha,21beta)-26,27-dinoronocerane-3,8,14,21-tetrol (2). and lycopodiin A (3), together with four known compounds, lycoclavanol (4), lycoclaninol (5), alpha-onocerin (6). and 3-epilycoclavanol (7). were isolated from Lycopodium japonicum THUNB (Lycopodiaceae). Their structures were established by means of spectroscopic analyses. Compounds 3 and 7 showed moderate antitumor activity. Compounds 4 and 6 exhibited acctylcholinestcrase inhibition activity.

Rab/Ypt GTPases play key roles in the regulation of vesicular trafficking. They perform most of their functions in a GTP-bound form by interacting with specific downstream effectors. The exocyst is a complex of eight polypeptides involved in constitutive secretion and functions as an effector for multiple Ras-related small GTPases, including the Rab protein Sec4p in yeast. In this study, we have examined the localization and function of the Sec15 exocyst subunit in mammalian cells. Overexpressed Sec15 associated with clusters of tubular/vesicular elements that were concentrated in the perinuclear region. The tubular/vesicular clusters were dispersed throughout the cytoplasm upon treatment with the microtubule-depolymerizing agent nocodazole and were accessible to endocytosed transferrin, but not exocytic cargo (vesicular stomatitis virus glycoprotein). Consistent with these observations, Sec15 colocalized selectively with the recycling endosome marker Rab11 and exhibited a GTP-dependent interaction with the Rab11 GTPase, but not with Rab4, Rab6, or Rab7. These findings provide the first evidence that the exocyst functions as a Rab effector complex in mammalian cells.

Members of the SNARE (soluble N-ethylmaleimide-sensitive fusion protein attachment protein receptor) superfamily [syntaxins, VAMPs (vesicle-associated membrane proteins) and SNAP25 (synaptosome-associated protein-25)-related proteins] are required for intracellular membrane-fusion events in eukaryotes. In neurons, assembly of SNARE core complexes comprising the presynaptic membrane-associated SNAREs syntaxin 1 and SNAP25, and the vesicle-associated SNARE VAMP2, is necessary for synaptic vesicle exocytosis. Several accessory factors have been described that associate with the synaptic SNAREs and modulate core complex assembly or mediate Ca2+ regulation. One such factor, Snapin, has been reported to be a brain-specific protein that interacts with SNAP25, and regulates association of the putative Ca2+-sensor synaptotagmin with the synaptic SNARE complex [Ilardi, Mochida and Sheng (1999) Nat. Neurosci. 2, 119–124]. Here we demonstrate that Snapin is expressed ubiquitously in neuronal and non-neuronal cells. Furthermore, using protein–protein-interaction assays we show that Snapin interacts with SNAP23, the widely expressed homologue of SNAP25, and that the predicted C-terminal helical domain of Snapin contains the SNAP23-binding site. Subcellular localization experiments revealed that Snapin is a soluble protein that exists in both cytosolic and peripheral membrane-bound pools in adipocytes. Moreover, association of Snapin with the plasma membrane was detected in cells overexpressing a Snapin–green fluorescent protein fusion protein. Finally, we show that Snapin is able to form a ternary complex with SNAP23 and syntaxin 4, suggesting that it is a component of non-neuronal SNARE complexes. An important implication of our results is that Snapin is likely to perform a general role in SNARE-mediated vesicle fusion events in non-neuronal cells in addition to its participation in Ca2+-regulated neurosecretion.

The MRL mouse has been shown to display unusual healing properties. In particular, when the ear pinna is hole punched, the hole that is made closes completely without scarring, with reformation of hair follicles and sebaceous glands, and regrowth of cartilage. Initial studies using (MRL/lpr × C57BL/6) F2 and backcross mice showed that this phenomenon is genetically determined and that multiple loci contribute to this quantitative trait. In the present study, with twice as many animals, we have confirmed many of the original heal loci and identified new ones. We have also found that this phenotype is sexually dimorphic in that female mice heal more quickly and more completely than male mice. To test the cause of this difference, we castrated both males and females. Castration of males led to better healing, although ovariectomy did not lead to worse healing in female mice. Finally, most heal loci were shown to be responsible for regulating healing primarily in male animals more than in females, or vice versa. Thus, sex plays a highly significant role in the closure of wounded tissue in this mammalian model of healing and regeneration.

The reaction of cardiac tissue to acute injury involves interacting cascades of cellular and molecular responses that encompass inflammation, hormonal signaling, extracellular matrix remodeling, and compensatory adaptation of myocytes. Myocardial regeneration is observed in amphibians, whereas scar formation characterizes cardiac ventricular wound healing in a variety of mammalian injury models. We have previously shown that the MRL mouse strain has an extraordinary capacity to heal surgical wounds, a complex trait that maps to at least seven genetic loci. Here, we extend these studies to cardiac wounds and demonstrate that a severe transmural, cryogenically induced infarction of the right ventricle heals extensively within 60 days, with the restoration of normal myocardium and function. Scarring is markedly reduced in MRL mice compared with C57BL/6 mice, consistent with both the reduced hydroxyproline levels seen after injury and an elevated cardiomyocyte mitotic index of 10–20% for the MRL compared with 1–3% for the C57BL/6. The myocardial response to injury observed in these mice resembles the regenerative process seen in amphibians.

We reported previously that acylation of an encephalitogenic peptide of myelin basic protein (MBP68-86) by attachment of palmitoyl chloride (PAL68-86) converted this peptide into a powerful tolerogen for EAE in the Lewis rat. In this study we show that T cell lines derived from a PAL68-86-protected rat proliferated poorly to MBP68-86 in vitro, even after repeated passages in this peptide and IL-2. Conversely, T cell lines derived from untreated rats that were challenged with MBP68-86 or PAL68-86 in CFA responded vigorously to MBP68-86 when propagated for many passages in this peptide but became gradually unresponsive after being propagated in the presence of PAL68-86. The modulation of the T cell lines by PAL68-86 in vitro was reflected by a significant reduction in their ability to transfer EAE to recipients. A high percentage of cells stained with an anti-Vbeta8.2 antibody, regardless of whether they were propagated in the presence of unmodified or acylated peptide. The results are consistent with the notion that tolerance induced by PAL68-86 operates by functional inactivation and provide the basis for the use of acylated peptides in the antigen-specific treatment of autoimmune diseases.

A more realistic mathematical influenza model including dynamics of Twitter, which may reduce and increase the spread of influenza, is introduced. The basic reproductive number is derived and the stability of the steady states is proved. The existence of Hopf bifurcation are also demonstrated by analyzing the associated characteristic equation. Furthermore, numerical simulations and sensitivity analysis of relevant parameters are also carried out. Our results show that the impact posed by the negative information of Twitter is not significant than the impact posed by the positive information of Twitter on influenza while the impact posed by the negative information of Twitter on the influenza virus is still extraordinary.