Modification of Proteinase Inhibitor II in Adzuki Beans during Germination

We investigated the effects of compounds isolated from a methanolic extract of rose hips on melanin biosynthesis in B16 mouse melanoma cells and the possible mechanisms responsible for the inhibition of melanin biosynthesis. We found that, among the isolated compounds, quercetin was a particularly potent melanogenesis inhibitor. To reveal the mechanism for this inhibition, the effects on tyrosinase of B16 mouse melanoma were measured. Quercetin decreased the intracellular tyrosinase activity as well as the tyrosinase activity in a cell culture-free system. We also examined the cellular level of tyrosinase protein and found that quercetin dose-dependently inhibited tyrosinase protein expression. We consider from these results that the inhibition of melanogenesis by quercetin was due to the inhibition of both tyrosinase activity and of the protein expression.     

Novel polymer biomaterials and interfaces inspired from cell membrane functions

Background

Materials with excellent biocompatibility on interfaces between artificial system and biological system are needed to develop any equipments and devices in bioscience, bioengineering and medicinal science. Suppression of unfavorable biological response on the interface is most important for understanding real functions of biomolecules on the surface. So, we should design and prepare such biomaterials.

Scoop of review

One of the best ways to design the biomaterials is generated from mimicking a cell membrane structure. It is composed of a phospholipid bilayered membrane and embedded proteins and polysaccharides. The surface of the cell membrane-like structure is constructed artificially by molecular integration of phospholipid polymer as platform and conjugated biomolecules. Here, it is introduced as the effectiveness of biointerface with highly biological functions observed on artificial cell membrane structure.

Major conclusions

Reduction of nonspecific protein adsorption is essential for suppression of unfavorable bioresponse and achievement of versatile biomedical applications. Simultaneously, bioconjugation of biomolecules on the phospholipid polymer platform is crucial for a high-performance interface.

General significance

The biointerfaces with both biocompatibility and biofunctionality based on biomolecules must be installed on advanced devices, which are applied in the fields of nanobioscience and nanomedicine.This article is part of a Special Issue entitled Nanotechnologies - Emerging Applications in Biomedicine.     

ESR study on synthetic glyceroglycolipid liposomal membranes

We previously reported that glyceroglycolipid liposomes without cholesterol activated mouse peritoneal macrophages in vivo and in vitro, whereas glyceroglycolipid liposomes containing equimolar cholesterol did not. In order to characterize the properties of the glyceroglycolipid membranes, ESR spectroscopic studies were carried out with an acyl spin-labeled galactosyl ceramide (SL-GC) or a headgroup spin-labeled phospholipid (SL-6-DPPA) in 1,2-dipalmitoyl[beta-cellobiosyl-(1'---3)]glycerol (Cel-DAG) liposomal membranes. The ESR spectrum of the SL-GC in the Cel-DAG liposomes at 37 degrees C was a single broad line, indicating that the SL-GC molecules were excluded almost completely from Cel-DAG domains and formed clusters in the membranes. The spectrum of SL-6-DPPA in the Cel-DAG liposomes at 37 degrees C showed broad resonance lines with the central peak being the highest, while that at 60 degrees gave narrow lines with the low-field peak being the highest. This observation and rotational correlation time analysis showed that the molecular motions of spin-label moiety of the SL-6-DPPA were extremely restricted at 37 degrees C but not above Tc. These results suggest that below Tc the Cel-DAG molecules are packed tightly and restricted in motion in the membrane. Incorporation of cholesterol into the Cel-DAG liposomal membranes gave (1) the spectra of the SL-GC triplet, and (2) the spectra of the SL-6-DPPA narrow resonance with the low-field peak being the highest. These results suggest that cholesterol disturbs the rigid-packed structure of the Cel-DAG membrane and increases the molecular motions of the Cel-DAG. The DSC analysis of Cel-DAG with and without cholesterol agreed well to the results of the ESR technique. Thus we assume that peritoneal macrophages recognize the rigid-packed carbohydrate residues which are restricted in motion on the Cel-DAG membranes.     

Calcification process dynamics in coral primary polyps as observed using a calcein incubation method

Calcification processes are largely unknown in scleractinian corals. In this study, live confocal imaging was used to elucidate the spatiotemporal dynamics of the calcification process in aposymbiotic primary polyps of the coral species Acropora digitifera. The fluorophore calcein was used as a calcium deposition marker and a visible indicator of extracellular fluid distribution at the tissue-skeleton interface (subcalicoblastic medium, SCM) in primary polyp tissues. Under continuous incubation in calcein-containing seawater, initial crystallization and skeletal growth were visualized among the calicoblastic cells in live primary polyp tissues. Additionally, the distribution of calcein-stained SCM and contraction movements of the pockets of SCM were captured at intervals of a few minutes. Our experimental system provided several new insights into coral calcification, particularly as a first step in monitoring the relationship between cellular dynamics and calcification in vivo. Our study suggests that coral calcification initiates at intercellular spaces, a finding that may contribute to the general understanding of coral calcification processes.     

Direct In Vivo Reprogramming with Sendai Virus Vectors Improves Cardiac Function after Myocardial Infarction

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Structural and functional characterization of HQL-79, an orally selective inhibitor of human hematopoietic prostaglandin D synthase

We determined the crystal structure of human hematopoietic prostaglandin (PG) D synthase (H-PGDS) as the quaternary complex with glutathione (GSH), Mg2+, and an inhibitor, HQL-79, having anti-inflammatory activities in vivo, at a 1.45-A resolution. In the quaternary complex, HQL-79 was found to reside within the catalytic cleft between Trp104 and GSH. HQL-79 was stabilized by interaction of a phenyl ring of its diphenyl group with Trp104 and by its piperidine group with GSH and Arg14 through water molecules, which form a network with hydrogen bonding and salt bridges linked to Mg2+. HQL-79 inhibited human H-PGDS competitively against the substrate PGH2 and non-competitively against GSH with Ki of 5 and 3 microm, respectively. Surface plasmon resonance analysis revealed that HQL-79 bound to H-PGDS with an affinity that was 12-fold higher in the presence of GSH and Mg2+ (Kd, 0.8 microm) than in their absence. Mutational studies revealed that Arg14 was important for the Mg2+-mediated increase in the binding affinity of H-PGDS for HQL-79, and that Trp104, Lys112, and Lys198 were important for maintaining the HQL-binding pocket. HQL-79 selectively inhibited PGD2 production by H-PGDS-expressing human megakaryocytes and rat mastocytoma cells with an IC50 value of about 100 microm but only marginally affected the production of other prostanoids, suggesting the tight functional engagement between H-PGDS and cyclooxygenase. Orally administered HQL-79 (30 mg/kg body weight) inhibited antigen-induced production of PGD2, without affecting the production of PGE2 and PGF2alpha, and ameliorated airway inflammation in wild-type and human H-PGDS-overexpressing mice. Knowledge about this structure of quaternary complex is useful for understanding the inhibitory mechanism of HQL-79 and should accelerate the structure-based development of novel anti-inflammatory drugs that inhibit PGD2 production specifically.     

Activation of Nrf2/Keap1 signaling and autophagy induction against oxidative stress in heart in iron deficiency

We investigated the effects of dietary iron deficiency on the redox system in the heart. Dietary iron deficiency increased heart weight and accumulation of carbonylated proteins. However, expression levels of heme oxygenase-1 and LC3-II, an antioxidant enzyme and an autophagic marker, respectively, in iron-deficient mice were upregulated compared to the control group, resulting in a surrogate phenomenon against oxidative stress.