Role of LOX‐1 in monocyte adhesion‐triggered redox,Akt/eNOS and Ca2+ signaling pathways in endothelial cells

This study was conducted to examine the role of lectin‐like oxidized low‐density lipoprotein receptor‐1 (LOX‐1) in monocyte adhesion‐induced redox‐sensitive, Akt/eNOS and Ca²⁺ signaling pathways in endothelial cells (ECs). LOX‐1 was blocked by an antibody‐neutralizing LOX‐1 TS92 or small interfering RNA. In cultured human aortic ECs, monocyte adhesion activated Rac1 and p47^phox, and increased NADPH oxidase activity and reactive oxygen species (ROS) generation within 30 min and NF‐κB phosphorylation within 1 h, resulting in redox‐sensitive gene expression. Akt and eNOS phosphorylation was induced 15 min after adding monocytes and returned to control level after 30 min, whereas NO production was not altered by monocyte adhesion. Blockade of LOX‐1 blunted the monocyte adhesion‐triggered redox‐sensitive signaling pathway and Akt/eNOS phosphorylation in ECs. Both endothelial intracellular Ca²⁺ mobilization and Ca²⁺ influx caused by monocyte attachment were markedly attenuated by pretreatment of ECs with TS92. This suggests that LOX‐1 is involved in redox‐sensitive, Akt/eNOS and Ca²⁺ signaling pathways in monocyte adhesion to ECs independent of oxidized low‐density lipoprotein (ox‐LDL). Furthermore, blockade of Ca²⁺ inhibited monocyte adhesion‐triggered Rac1 and p47^phox activation and ROS generation in ECs, whereas Ca²⁺ signaling was suppressed by blockade of NADPH oxidase and ROS generation. Finally, TS92 blocked the monocyte adhesion to ECs stimulated with or without tumor necrosis factor‐α or ox‐LDL. We provide evidence that LOX‐1 plays a role in redox‐sensitive, Akt/eNOS and Ca²⁺ signaling pathways in monocyte adhesion to ECs independent of the ox‐LDL–LOX‐1 axis. J. Cell. Physiol. 220: 706–715, 2009. © 2009 Wiley‐Liss, Inc.     

Increased lipid peroxidation in Down's syndrome mouse models

Elevated oxidative stress has been suggested to be associated with the features of Down's syndrome (DS). We previously reported increased oxidative stress in cultured cells from the embryonic brain of Ts1Cje, a mouse genetic DS model. However, since in vivo evidence for increased oxidative stress is lacking, we here examined lipid peroxidation, a typical marker of oxidative stress, in the brains of Ts1Cje and another DS mouse model Ts2Cje with an overlapping but larger trisomic segment. Accumulations of proteins modified with the lipid peroxidation-derived products, 13-hydroperoxy-9Z,11E-octadecadienoic acid and 4-hydroxy-2-nonenal were markedly increased in Ts1Cje and Ts2Cje brains. Analysis with oxidation-sensitive fluorescent probe also showed that reactive oxygen species themselves were increased in Ts1Cje brain. However, electron spin resonance analysis of microdialysate from the hippocampus of Ts1Cje showed that antioxidant activity remained unaffected, suggesting that the reactive oxygen species production was accelerated in Ts1Cje. Proteomics approaches with mass spectrometry identified the proteins modified with 13-hydroperoxy-9Z,11E-octadecadienoic acid and/or 4-hydroxy-2-nonenal to be involved in either ATP generation, the neuronal cytoskeleton or antioxidant activity. Structural or functional impairments of these proteins by such modifications may contribute to the DS features such as cognitive impairment that are present in the Ts1Cje mouse.     

Oculocutaneous albinism type 4: six novel mutations in the membrane-associated transporter protein gene and their phenotypes

Oculocutaneous albinism type 4 (OCA4) is an autosomal recessive hypopigmentary disorder caused by mutations in the Membrane-Associated Transporter Protein gene (SLC45A2). The SLC45A2 protein is a 530-amino-acid polypeptide that contains 12 putative transmembrane domains, and appears to be a transporter that mediates melanin synthesis. Eighteen pathological mutations have been reported so far. In this study, six novel mutations, p.Y49C (c.146A > G), p.G89R (c.265G > A), p.C229Y (c.686G > A), p.T437A (c.1309A > G), p.T440A (c.1318A > G) and p.G473D (c.1418G > A) were found in eight Japanese patients with various clinical phenotypes. The phenotypes of OCA4 were as various as the other types of OCA and probably depended on the mutation sites in the SLC45A2 gene.     

Estimation of handgrip force using frequency-band technique during fatiguing muscle contraction

In this paper, we propose a force estimation model to compute the handgrip force from SEMG signal during fatiguing muscle contraction tasks. The appropriate frequency range was analyzed using various combinations of a wavelet scale, and the highest accuracy was achieved at a range from 242 to 365 Hz. After that, eight healthy individuals performed a series of static (70%, 50%, 30%, and 20% MVC) and dynamic (0–50% MVC) muscle contraction tasks to evaluate the performance of this technique in comparison with that of former method using the Root Mean Square of the SEMG signal. Both methods had comparable results at the beginning of the experiments, before the onset of muscle fatigue. However, differences were clearly observed as the degree of muscle fatigue began to increase toward the endurance time. Under this condition, the estimated handgrip force using the proposed method improved from 17% to 134% for static contraction tasks and 40% for dynamic contraction tasks. This study overcomes the limitation of the former method during fatiguing muscle contraction tasks and, therefore, unlocks the potential of utilizing the SEMG signal as an indirect force estimation method for various applications.     

Molecular properties of the glucosaminidase AcmA from Lactococcus lactis MG1363: Mutational and biochemical analyses

The major autolysin AcmA of Lactococcus lactis ssp. cremoris MG1363 is a modular protein consisting of an N-terminal signal sequence, a central enzymatic region (glu_acma as a glucosaminidase), and a C-terminal cell-recognition domain (LysM123). glu_acma (about 160 amino acids) belongs to the glycoside hydrolase (GH) 73 family, and the two acidic residues E128 and D153 have been thought to be catalytically important. In this study, amino-acid substitution analysis of AcmA was first carried out in the Escherichia coli system. Point mutations E94A, E94Q, E128A, D153A, and Y191A markedly reduced cell-lytic activity (3.8%, 1.1%, 4.2%, 4.8%, and 2.4%, respectively), whereas E128Q and D153N retained significant residual activities (32.1% and 44.0%, respectively). On the other hand, Y191F and Y191W mutations retained high activities (66.2% and 46.0%, respectively). These results showed that E94 (rather than E128 and D153) and the aromatic residue Y191 probably play important roles in catalysis of AcmA. Together with mutational analysis of another GH73 glucoaminidase Glu_atlwm from the Staphylococcus warneri M autolysin Atl_WM, these results suggested that the GH73 members cleave a glycosidic bond via a substrate-assisted mechanism, as postulated in the GH20 members. AcmA and Glu_atlwm were purified from E. coli recombinant cells, and their enzymatic properties were studied.     

A quantitative method for analyzing establishing-efficiency of persistent viral infection

A quantitative method for analyzing establishing-efficiency of persistent infection was devised. The efficiency of hPIV2 CA and SV5 T1 strains was found to be high, that is, 0.1∼0.3 (an efficiency of 1.0 indicates that 100% of the virus-infected cells became persistently infected). The efficiency of the SV5 WR strain was also high, approximately 0.1, though the virus had no ability to immediately establish a steady state of persistent infection in whole cell-culture systems. At about 0.0007, the efficiency of SV41 was almost the same as that of the hPIV2 Toshiba strain. The establishing efficiencies of various rSeV were further analyzed in detail. The efficiencies of the rSeV(PA), rSeV(Ppi) and rSeV(HNpi) were below the limit of detection, while that of rSeV(Lpi) was nearly 1. Although the efficiency was around 0.001, the rSeV(Mpi) and the rSeV(Fpi) were unexpectedly found to be capable of forming persistently-infected cells, indicating that both the Fpi and Mpi proteins contribute to the establishing efficiency of persistent infection of SeVpi.     

Bactrocerin‐1: A novel inducible antimicrobial peptide from pupae of oriental fruit fly Bactrocera dorsalis Hendel

A novel antimicrobial peptide, Bactrocerin‐1, was purified and characterized from an immunized dipteran insect, Bactrocera dorsalis. Bactrocerin‐1 has 20 amino acid residues with a mass of 2,325.95 Da. The amino acid sequence of Bactrocerin‐1 showed very high similarity to the active fragment (46V‐65S‐NH₂) of Coleoptericin A. The composition of amino acid residues revealed that Bactrocerin‐1 is a hydrophobic, positively charged, and Lys/Ile/Gly‐rich peptide. Minimal growth inhibition concentration (MIC) measurements for synthesized Bactrocerin‐1 showed a very broad spectrum of anti‐microbial activity against Gram‐positive bacteria, Gram‐negative bacteria, and fungi. Bactrocerin‐1 did not show hemolytic activity toward mouse red blood cells even at a concentration of 50 µM. Analysis of the Helical‐wheel projection and the CD spectrum suggested that Bactrocerin‐1 contains the amphipathic α‐helix. © 2009 Wiley Periodicals, Inc.     

Effects of home and office care denture reliners on maxillary complete dentures

doi:10.1111/j.1741‐2358.2009.00308.x
Effects of home and office care denture reliners on maxillary complete dentures Objectives: The aim of this study was to evaluate the effects of office (OR) and home (HR) care temporary denture reliners on satisfaction and functional outcomes in maxillary complete denture wearers. Methods: Thirty‐four maxillary edentulous patients received application of either OR or HR to their maxillary complete dentures. Patient’s ratings on satisfaction and functional aspects were measured on a 100‐mm visual analogue scale at 4 days post‐application. Associations between baseline ratings and improvement were also assessed. Results: There were no significant differences between the two groups in satisfaction ratings or in the functional outcomes. The OR group showed a significant improvement in mastication and retention, whereas the HR group exhibited a significant improvement in general satisfaction and mastication. Improvement was negatively associated with baseline ratings of speech, ease of cleaning, stability and retention in the OR groups and across all variables, except ease of cleaning, in the HR group. Conclusion: When used correctly, home care denture therapy can be as effective as office applied temporary liner in improving satisfaction with problematic maxillary dentures.     

Involvement of Antibacterial Peptide Defensin in Tick Midgut Defense

Animals are constantly threatened by pathogenic microorganisms and have developed cellular and humoral immune responses to combat these infections. Invertebrates possess only an innate non-specific immune response. Antimicrobial substances are major components of innate immunity not only in invertebrates but also in vertebrates. Despite the importance of ticks as vectors of disease very little is known about their immune system. Our recent studies have revealed that four defensin isoforms are present in Ornithodoros moubata. These four isoforms are constitutively expressed in the midgut and up-regulated in response to blood feeding. Moreover, a mature peptide of defensin isoform A has been isolated from the tick midgut lumen. These findings indicate Ornithodoros defensins are involved in tick midgut defense against potentially harmful invasive microbes. This revised version was published online in July 2006 with corrections to the Cover Date.     

Transient accumulation of jasmonic acid during the synchronized hypersensitive cell death in Tobacco mosaic virus-infected tobacco leaves

Jasmonic acid (JA) transiently accumulated during temperature-dependent synchronous necrotic lesion formation in Tobacco mosaic virus-infected tobacco leaves. The accumulation of JA was preceded by activation of a tobacco mitogen-activated protein kinase, WIPK, which functions upstream of JA in wound signal transduction pathways.