Nonthermal Plasma‐Induced Degradation of Morin and Enhancement of Biological Activities

In the present study, non‐thermal dielectric barrier discharge (DBD) plasma of induced structural changes of morin resulted in the isolation of one previously undescribed benzofuranone derivative, along with two known compounds. The chemical structures of these degradation products were elucidated by UV, NMR and FAB‐MS spectroscopic analyses. The isolated three compounds showed potent antioxidative activities in two different tests, with IC₅₀ values in the range of 12.9–41.8 μm in the 2,2′‐azino‐bis (3‐ethylbenzothiazoline‐6‐sulfonic acid) (ABTS⁺) radical scavenging activity, 19.0–71.9 μm for hydroxyl radical scavenging activity test. Furthermore, the new methoxylated benzofuranone exhibited enhancement of inhibitory effects against pancreatic lipase with an IC₅₀ value of 90.7±1.6 μm , when compared to the parent morin. These results suggested that the degradation products isolated from plasma exposed morin might be beneficial for prevention of obesity and related diseases.     

Interleukin-1-β and Tumor Necrosis Factor-α Increase Peripheral-Type Benzodiazepine Binding Sites in Cultured Polygonal Astrocytes

Peripheral-type benzodiazepine binding sites (PTBBS) are markedly increased in the injured CNS. Astrocytes appear to be the primary cell type which express increased PTBBS. Because certain cytokines within the injured CNS are potent mitogens for astrocytes, we examined the effects of two such cytokines, interleukin (IL)-1 beta and tumor necrosis factor (TNF), on PTBBS in cultured astrocytes using [3H]Ro 5-4864 as the specific ligand. Purified cultures of either polygonal or process-bearing astrocytes were prepared from neonatal rat cerebral hemispheres. At a concentration of 1.8 nM, specific binding of the radioactive ligand to polygonal astrocytes reached equilibrium within 60 min and was half-maximal by 5-10 min. By contrast, specific binding to process-bearing astrocytes barely exceeded background levels. IL-1 and TNF increased PTBBS within polygonal astrocytes in both dose- and time-dependent manners. At 10-50 ng/ml, IL-1 beta and TNF-alpha elevated [3H]Ro 5-4864 binding in polygonal astrocyte cultures 65 and 87%, respectively, above the level in control cultures. However, no changes in PTBBS were seen within polygonal astrocytes after IL-2 treatment. Scatchard analysis of saturation binding experiments suggested that the increase in PTBBS promoted by TNF was due to an increased number of binding sites present in polygonal astrocytes and not due to an increase in receptor affinity. Binding data suggested that PTBBS within cultures of process-bearing astrocytes were virtually absent irrespective of the treatment. These in vitro data suggest that certain cytokines found in the injured brain may be involved in up-regulating PTBBS within a particular subtype of astrocyte.     

Secretion of Recombinant Pediocin PA-1 by Bifidobacterium longum, Using the Signal Sequence for Bifidobacterial α-Amylase

A recombinant DNA, encoding the chimeric protein of the signal sequence for bifidobacterial α-amylase mature pediocin PA-1, was introduced into Bifidobacterium longum MG1. Biologically active pediocin PA-1 was successfully secreted from the strain and showed bactericidal activity against Listeria monocytogenes and the same molecular mass as native pediocin PA-1.     

Effectiveness of Losartan-Loaded Hyaluronic Acid (HA) Micelles for the Reduction of Advanced Hepatic Fibrosis in C3H/HeN Mice Model

Advanced hepatic fibrosis therapy using drug-delivering nanoparticles is a relatively unexplored area. Angiotensin type 1 (AT1) receptor blockers such as losartan can be delivered to hepatic stellate cells (HSC), blocking their activation and thereby reducing fibrosis progression in the liver. In our study, we analyzed the possibility of utilizing drug-loaded vehicles such as hyaluronic acid (HA) micelles carrying losartan to attenuate HSC activation. Losartan, which exhibits inherent lipophilicity, was loaded into the hydrophobic core of HA micelles with a 19.5% drug loading efficiency. An advanced liver fibrosis model was developed using C3H/HeN mice subjected to 20 weeks of prolonged TAA/ethanol weight-adapted treatment. The cytocompatibility and cell uptake profile of losartan-HA micelles were studied in murine fibroblast cells (NIH3T3), human hepatic stellate cells (hHSC) and FL83B cells (hepatocyte cell line). The ability of these nanoparticles to attenuate HSC activation was studied in activated HSC cells based on alpha smooth muscle actin (α-sma) expression. Mice treated with oral losartan or losartan-HA micelles were analyzed for serum enzyme levels (ALT/AST, CK and LDH) and collagen deposition (hydroxyproline levels) in the liver. The accumulation of HA micelles was observed in fibrotic livers, which suggests increased delivery of losartan compared to normal livers and specific uptake by HSC. Active reduction of α-sma was observed in hHSC and the liver sections of losartan-HA micelle-treated mice. The serum enzyme levels and collagen deposition of losartan-HA micelle-treated mice was reduced significantly compared to the oral losartan group. Losartan-HA micelles demonstrated significant attenuation of hepatic fibrosis via an HSC-targeting mechanism in our in vitro and in vivo studies. These nanoparticles can be considered as an alternative therapy for liver fibrosis.     

Cloning of a Vero toxin (VT2) gene from a VT2-converting phage isolated from Escherichia coli 0157: H7

Abstract A Vero toxin (VT2 or Shiga-like toxin II)-converting phage was isolated from Escherichia coli 0157: H7 strain J-2. Nontoxigenic E. coli C600 produced VT2 when lysogenized with the toxin-converting phage. Eco RI fragments of the phage DNA were ligated with Eco RI-digested pBR322 or pUC118 and were transformed into E. coli MC1061 or MV1184. Transformants exhibiting VT2 production commonly contained a 4.6 kb Eco RI fragment. It was found that a 2.3 kb Kpn I- Sph I fragment coded VT2 production and that this fragment hybridized weakly with the 2.1 kb fragment encoding VT1.     

Multiple actions of superoxide dismutase: why can it both inhibit and stimulate reduction of oxygen by hydroquinones?

Superoxide dismutase can either inhibit or stimulate autoxidation of different hydroquinones, suggesting multiple roles for O2.-. Inhibitory actions of superoxide dismutase include termination of O2.(-)-propagated reaction chains and metal chelation by the apoprotein. Together, chelation of metals and termination of O2.(-)-propagated chains can effectively prevent reduction of oxygen. Chain termination by superoxide dismutase can thus account for negligible accumulation of H2O2 without invoking a superoxide:semiquinone oxidoreductase activity for this enzyme. One stimulatory action of superoxide dismutase is to decrease thermodynamic limitations to reduction of oxygen. Whether superoxide dismutase inhibits or accelerates an autoxidation depends on the reduction potentials of the quinone and the availability of metal coordination for inner sphere electron transfers.     

Supplement of nutrients for effective cultivation of hepatitis B surface antigen-producing recombinant yeast

Summary In the hepatitis B surface antigen (HBsAg)-producing recombinant yeast culture medium, the supply of Bacto-yeast nitrogen base without amino acids was found to be inadequate due to the lack of the several kinds of vitamins and trace elements. When the culture medium for this recombinant yeast was supplemented with sufficient vitamins and trace elements, its growth, HBsAg production and the stability of plasmid were improved.     

Purification and characterization of a heat-stable enterotoxin of Vibrio mimicus

A heat-stable enterotoxin produced by Vibrio mimicus (VM-ST) was studied. VM-ST was purified from a culture supernatant of V. mimicus strain AQ-0915 by ammonium sulfate fractionation, hydroxyapatite treatment, ethanol extraction, column chromatography on both SP-Sephadex C-50 and DEAE-Sephadex A-25, and HPLC, and the recovery rate was about 15%. Purified VM-ST was heat-stable. VM-ST activity was cross-neutralized by anti-STh antiserum. The amino acid composition of the purified VM-ST was determined 17 amino acid residues in the following sequence: Ile-Asp-Cys-Cys-Glu-Ile-Cys-Cys-Asn-Pro-Ala-Cys-Phe-Gly-Cys-Leu-Asn. This composition and sequence were identical to those of V. cholerae non-O1-ST. These results clearly demonstrate the production of a characteristic VM-ST by V. mimicus.