Antioxidant Effect of Peptide in Combination with Sugar on Autoxidation of Edible Oils

The antioxidant effect of various combinations of peptide and sugar was investigated by an oven-storage test using lard as substrate. High antioxidant activity was resulted from combining a peptides with branched-chain amino acids and xylose. For this effect, the presence of a branched-chain amino acid was more favorable at the N-terminal position of the peptide than at the C-terminal position. A synergistic effect was observable with xylose at a molar ratio of xylose-peptide of 0.05. The leucylglycine-xylose composition was also effective for preventing oxidation in selected vegetable oils.     

A Microfibril Formation from Depolymerized Chitosan by N-Acetylation

The geometrical isomers of O-4-tert-butylcyclohexyl methylthiocarbamate were prepared by way of the corresponding dithiocarbonates. The O-trans-isomer was obtained from a mixture of cis- and trans-4-tert-butylcyclohexanols via an alkoxide formation involving biassed equilibration, whereas the O-cis isomer was from the cis-cyclohexanol via an alkoxide formation free from equilibration.

The acid-catalyzed rearrangement of the O-cis thiocarbamate gave a 1:3 mixture of S-cis- and S-trans-4-tert-butylcyclohexyl methylthiocarbamates, whereas that of the O-trans thiocarbamate afforded a 9:1 mixture of S-cis and S-trans products.

These results, together with the data from a study on the reactions of O-cis-3,3,5-tri-methylcyclohexyl methylthiocarbamate and the O-neopentyl analog, indicate that the acid-catalyzed rearrangement proceeded mostly through an S_N2 type of transalkylating mechanism to give the S-isomer in the case where the approach of nucleophiles was not sterically blocked, otherwise the reaction gave S_N1-type products.     

(22E,24S)-5α-Ergosta-7, 22-dien-3β-ol from the seeds of Cucumis sativus

(22E,24S)-5α-Ergosta-7,22-dien-3β-ol isolated from the seeds of Cucumis sativus was shown to be the 24S-epimer, i.e. stellasterol,     

Raman spectra of copoly(D,L-alanines)

Raman spectra in the region 1000–150 cm^?1 were measured for copoly(D ,L -alanines) with the D -residue contents, 3, 7, 10, and 20%, and compared with the spectrum of the α-helical poly-L -alanine. The 532- and 378-cm^?1 peaks were assigned to the L -residues with a right-handed α-helix-like local conformation or to the D -residues with a left-handed α-helix-like local conformation. From the intensity of the latter peak the contents of these local conformations were estimated as a function of the D -residue contents for the copolymers. The 264-cm^?1 peak, which has been assigned to the breathing vibration of the α-helical poly-L -alanine, shows a marked decrease in its intensity upon the introduction of the D residues. This result suggests that the overall deformation vibration of the α-helix arises from rather long sequences of the L - and D -alanine residues with the α-helical conformation and that the intensity of this vibration depends on the content of these sequences in the copolymers.     

Increased Induction of Apoptosis by a Sendai Virus Mutant Is Associated with Attenuation of Mouse Pathogenicity

An avirulent mutant of Sendai virus, Ohita-MVC11 (MVC11), was generated from a highly virulent field strain, Ohita-M1 (M1), through successive passages in LLC-MK₂ cell cultures (M. Itoh, Y. Isegawa, H. Hotta, and M. Homma, J. Gen. Virol. 78:3207-3215, 1997). In LLC-MK₂ cells, MVC11 induced a high degree of apoptotic cell death that was demonstrated by chromatin condensation of the nucleus and DNA fragmentation, and production of MVC11 declined markedly after prolonged culture. On the other hand, M1 did not induce prominent apoptosis and maintained high virus titers. In primary mouse pulmonary epithelial cell cultures, M1 replicated rather slowly to reach maximum level of virus production at 3 days postinfection, and high levels of virus production were maintained thereafter without causing apoptosis. In contrast, MVC11, which produced 20 times more progeny virus than M1 at 1 day postinfection, induced a high degree of apoptotic cell death before the virus replication cycle was completed. Accordingly, the production of progeny virus was strongly inhibited thereafter. In the lungs of mice infected with MVC11, virus antigens and signals of DNA fragmentation detected by the in situ terminal deoxynucleotidyltransferase-mediated dUTP nick end-labeling technique colocalized in bronchial epithelial cells, clearly demonstrating that infection by MVC11 triggered apoptosis in vivo as well as in vitro. These results suggest the possibility that induction of apoptosis by MVC11 plays an important role in attenuation of mouse pathogenicity by restricting progeny virus production in the lung. The C protein was shown to have the capacity to induce apoptosis, and the increased level of the C protein in MVC11-infected cells was considered to account partly, if not entirely, for the induction of apoptosis.     

Cellulose in the house of the appendicularianOikopleura rufescens

Summary By electron diffraction analysis, highly crystalline cellulose Iβ was found in the house (a special structure in which the tunicate lives) of the appendicularianOikopleura rufescens. Cellulose microfibrils 20 nm in width were observed in a random array or highly organized with rectangular spacing of 2 to 10 (im in the house. The bundled cellulose microfibrils formed in the inlet filters, which are highly ordered meshwork structures. This paper provides the first account of the existence of cellulose in the house of an appendicularian. Our findings showed that the house and tunic are homologous tissues among the tunicates, and that the common ancestor of the tunicates (ascidians, thaliaceans, and appendicularians) already possessed cellulose-biosynthetic ability.