Synthesis of delta(E)Phe-containing tripeptide via photoisomerization and its conformation in solution

A new synthetic route to (E)-beta-phenyl-alpha,beta-dehydroalanine (delta(E)Phe)-containing peptide was presented via photochemical isomerization of the corresponding (Z)-beta-phenyl-alpha,beta-dehydroalanine (delta(Z)Phe)-containing peptide. By applying this method to Boc-Ala-delta(Z)Phe-Val-OMe (Z-I: Boc, t-butoxycarbonyl; OMe, methoxy), Boc-Ala-delta(E)Phe-Val-OMe (E-I) was obtained. The identification of peptide E-I was evidenced by 1H-nmr, 13C-nmr, and uv absorption spectroscopy, elemental analysis, and hydrogenation. The conformation of peptide E-I in CDCl3 was investigated by 1H-nmr spectroscopy (solvent dependence of NH chemical shift and difference nuclear Overhauser effect). Interestingly, peptide E-I differed from peptide Z-I in the hydrogen-bonding mode. Namely, for peptide Z-I, only Val NH participates in intramolecular hydrogen bonding, which leads to a type II beta-turn conformation supported by hydrogen bonding between CO(Boc) and NH(Val). On the other hand, for peptide E-I, two NHs, delta(E)Phe NH and Val NH, participate in intramolecular hydrogen bonding. In both peptides, a remarkable NOE (approximately 11-13%) was observed for Ala C(alpha) H-deltaPhe NH pair. Based on the nmr data and conformational energy calculation, it should be concluded that peptide E-I takes two consecutive gamma-turn conformations supported by hydrogen bonding between CO(Boc) and NH(delta(E)Phe), and between CO(Ala) and NH(Val) as its plausible conformation.     

Determination of aromatic compounds by high-performance liquid chromatography with on-line photoreactor and peroxyoxalate chemiluminescence detection.

This paper describes a novel high-performance liquid chromatographic (HPLC) method for the determination of aromatic compounds with peroxyoxalate chemiluminescence (PO-CL ) detection following on-line UV irradiation. Aromatic compounds were UV irradiated (254 nm, 15 W) to generate hydrogen peroxide, which was determined via PO-CL detection using a mixture of bis(2,4,6-trichlorophenyl)oxalate (aryloxalate) and 2,4,6,8-tetrathiomorpholinopyrimido[5,4-d]pyrimidine (fluorophore) as a post-column CL reagent. Generation of hydrogen peroxide from aromatic compounds was confirmed using a flow injection analysis (FIA) system incorporating an enzyme column reactor immobilized with catalase. The conditions for UV irradiation were optimized using benzene and monosubstituted benzenes (phenol, benzaldehyde, nitrobenzene and N,N-dimethylaniline) by an HPLC system to evaluate the analytical performance of the proposed system. The detection limits for benzene and monosubstituted benzenes were in the range 2.1-124 pmol/injection at signal:noise (S:N) ratio = 3. Monocyclic and polycyclic hydrocarbons were also employed to investigate their CL properties. The possibility of PO-CL detection for a wide variety of aromatic compounds was shown for the first time.     

Flavonoid glycosides in Malabar spinach Basella alba inhibit the growth of Spodoptera litura larvae

Basella alba is a perennial plant of the Basellaceae and is known by various common names including Malabar spinach. There are few insects that cause damage to B. alba. In this study, we examined the effect of B. alba leaves on the growth of Spodoptera litura larvae. B. alba leaves and a methanolic extract of the leaves inhibited the growth of S. litura larvae. Half of the larvae reared on the leaves died within 1 week. We found that two flavonoids, vitexin, and vitexin-2″-O-arabinofuranoside, were abundant in the methanol extract of leaves. When larvae were reared on purified vitexin or vitexin-2″-O-arabinofuranoside, their growth was significantly impaired compared with larvae reared on control spinach leaves. These results suggested that the flavonoid glycosides in B. alba leaves act as deterrents to S. litura larvae.     

Triterpene Glucosides from the Leaves of Aralia elata and Their Cytotoxic Activities

Three new triterpene glucosides, named congmuyenosides C–E ( 1 – 3 , resp.), along with four known ones, were isolated from an EtOH extract of Aralia elata (Miq .) Seem . leaves. The structures of the new compounds were identified as 3‐O‐{β‐D ‐glucopyranosyl‐(1→3)‐β‐D ‐glucopyranosyl‐(1→3)‐[β‐D ‐glucopyranosyl‐(1→2)]‐β‐D ‐glucopyranosyl}caulophyllogenin ( 1 ), 3‐O‐{β‐D ‐glucopyranosyl‐(1→3)‐β‐D ‐glucopyranosyl‐(1→3)‐[β‐D ‐glucopyranosyl‐(1→2)]‐β‐D ‐glucopyranosyl}hederagenin 28‐O‐β‐D ‐glucopyranosyl ester ( 2 ), 3‐O‐{β‐D ‐glucopyranosyl‐(1→3)‐β‐D ‐glucopyranosyl‐(1→3)‐[β‐D ‐glucopyranosyl‐(1→2)]‐β‐D ‐glucopyranosyl}echinocystic acid 28‐O‐β‐D ‐glucopyranosyl ester ( 3 ) on the basis of spectral analyses, including MS, ¹H‐NMR, ¹³C‐NMR, DEPT, HSQC, HMBC, NOESY, and HSQC‐TOCSY experiments. All isolates obtained were evaluated for their cytotoxic activities against three human tumor cell lines (HepG2, SKOV3, and A549). Compound 3 showed significant cytotoxicity against A549 cell line (IC₅₀ 9.9±1.5 μM ).     

A series of thiazole derivatives bearing thiazolidin-4-one as non-competitive ADAMTS-5 (aggrecanase-2) inhibitors

A series of thiazole bearing thiazolidin-4-one was discovered via high-throughput screening as non-competitive inhibitors of ADAMTS-5. Compound 31 appeared to give the best ADAMTS-5 inhibition and good selectivity over other metalloproteases.     

Effects of age,body size and season on food consumption and digestion of captive dugongs (Dugong dugon)

Food consumption and digestion of male and female dugongs (Dugong dugon) was examined by analyzing long-term (1979–1998) feeding records at Toba Aquarium (Japan). Throughout all captive feeding periods, dugongs consumed eelgrass (Zostera marina) and showed steady increases in feed consumption with a consistent weight gain of 42–45?kg a year. The daily consumption of male and female dugongs increased from 10–15?kg to 23–26?kg of fresh eelgrass, accounting for approximately 14 and 7% of their body weight at one and seven years old, respectively. Both dugongs had a marginal dry matter digestibility of over 90%. Food consumption varied between seasons and individuals. There were major reductions (P<0.05) in consumption by the male in November and January and by the female in August and September. The seasonal reductions in food consumption coincided with high digestibility of eelgrass.     

Development of a Highly Sensitive Immuno-PCR Assay for the Measurement of α-Galactosidase A Protein Levels in Serum and Plasma

Fabry disease is an X-linked genetic disorder caused by defects in the α-galactosidase A (GLA) gene, and heterogeneous mutations lead to quantitative and/or qualitative defects in GLA protein in male patients with Fabry disease. Random X-chromosomal inactivation modifies the clinical and biochemical features of female patients with Fabry disease. Functional polymorphisms have been frequently reported in recent times, and these increase the difficulty of understanding the pathogenetic basis of the disease. To date, GLA protein level has been measured using an enzyme-linked immunosorbent assay (ELISA). However, ELISA is not highly sensitive due to the high background noise. In this paper, we introduce a novel application of the immuno-polymerase chain reaction (PCR) method (termed Multiple Simultaneous Tag [MUSTag]) for measurement of the GLA protein level in blood samples. We compared the sensitivities of the MUSTag method with plates or magnetic beads with those of ELISA for recombinant human GLA and found that the apparent maximal sensitivity was higher for the former than for the latter. We then measured the GLA concentrations in serum and plasma from male patients with classic Fabry disease (Male Fabry), females with Fabry disease (Female Fabry), male subjects harboring the functional polymorphism p.E66Q (E66Q), and control (Control) subjects. Our results revealed that compared to the MUSTag plate and ELISA, the MUSTag beads assay afforded a clearer estimation of the GLA protein levels in the serum and plasma with minimal or no background noise, although all the methods could differentiate between the Male Fabry, E66Q, and Control groups. The Female Fabry group showed characteristic heterogeneity, which was consistent with the X-linked inheritance. This novel method is expected to be useful for the sensitive determination of GLA level in blood and elucidation of the pathogenetic basis of Fabry disease.     

Blue-Violet Laser Modification of Titania Treated Titanium: Antibacterial and Osteo-Inductive Effects

Background

Many studies on surface modifications of titanium have been performed in an attempt to accelerate osseointegration. Recently, anatase titanium dioxide has been found to act as a photocatalyst that expresses antibiotic properties and exhibits hydrophilicity after ultraviolet exposure. A blue-violet semiconductor laser (BV-LD) has been developed as near-ultraviolet light. The purpose of this study was to investigate the effects of exposure to this BV-LD on surface modifications of titanium with the goal of enhancing osteoconductive and antibacterial properties.

Methods

The surfaces of pure commercial titanium were polished with #800 waterproof polishing papers and were treated with anatase titania solution. Specimens were exposed using BV-LD (λ = 405 nm) or an ultraviolet light-emitting diode (UV-LED, λ = 365 nm) at 6 mW/cm² for 3 h. The surface modification was evaluated physically and biologically using the following parameters or tests: surface roughness, surface temperature during exposure, X-ray diffraction (XRD) analysis, contact angle, methylene blue degradation tests, adherence of Porphyromonas gingivalis, osteoblast and fibroblast proliferation, and histological examination after implantation in rats.

Results

No significant changes were found in the surface roughness or XRD profiles after exposure. BV-LD exposure did not raise the surface temperature of titanium. The contact angle was significantly decreased, and methylene blue was significantly degraded. The number of attached P. gingivalis organisms was significantly reduced after BV-LD exposure compared to that in the no exposure group. New bone was observed around exposed specimens in the histological evaluation, and both the bone-to-specimen contact ratio and the new bone area increased significantly in exposed groups.

Conclusions

This study suggested that exposure of titanium to BV-LD can enhance the osteoconductivity of the titanium surface and induce antibacterial properties, similar to the properties observed following exposure to UV-LED.     

Role of Intracellular and Extracellular MicroRNA-92a in Colorectal Cancer

Colorectal cancer is one of the leading causes of cancer-related death worldwide. Previous studies have shown that miR-92a has an oncogenic function in several cancers and that its up-regulation is correlated with malignant clinicopathologic behaviors of colorectal cancer. It also has been suggested that circulating miR-92a in patients' plasma can be a potential biomarker for colorectal cancer. However, the precise roles of intracellular and extracellular miR-92a are not yet understood. In this study, we examined the expression levels of miR-92a in colorectal tumors (38 cancer specimens and 56 adenoma specimens) and paired adjacent nontumorous tissues. Increased expression of miR-92a was frequently observed in the cancers compared with that in the adenomas and was correlated with advanced clinical stages, tumor depth, and size. We also demonstrated that the levels of miR-92a within microvesicles (MVs) in the plasma of mice bearing colon cancer xenografts were significantly increased compared with those in control mice. One of the roles of intracellular and extracellular miR-92a was shown to be down-regulation of Dickkopf-3 (Dkk-3), a presumed tumor suppressor gene. Within the colon cancer cells, suppression of Dkk-3 by miR-92a contributed to the cell proliferation. Extracellular miR-92a packed within MVs secreted by colon cancer cells was delivered into endothelial cells and contributed to the proliferation and motility of these cells through down-regulation of the same target gene, Dkk-3. These data suggest that intracellular and extracellular miR-92a had important roles in tumor growth and the tumor microenvironment in colorectal cancer.