Diversity and Complexity of Ceramide Signalling in Apoptosis

Sphingolipid ceramide has emerged as a lipid messenger of cell functions including differentiation and apoptosis. Diverse kinds of stresses (ultraviolet, irradiation, heat shock and hypoxia) and biological factors (TNF-, IFN-γ and Fas antibody) require ceramide generation to execute apoptosis. The review summarises the diversity and complexity of up- and downstream of ceramide signalling in apoptosis and clinical implications of ceramide-induced apoptosis.     

Structure and biological activities of hypochlorite oxidized zymosan

Zymosan (ZYM), a strong complement activating yeast cell preparation, is also a potent inflammatory substance, which shows immunopharmacological activity. Major component of ZYM is β-glucan but contains other constituents, such as mannan, protein, and nucleic acid. We applied sodium hypochlorite (NaClO) treatment to ZYM to reduce impurities and compared the activity with native/parent ZYM. Oxidized ZYM (OX-ZYM) became a nitrogen-free agent. By NMR analysis of native OX-ZYM and zymolyase (endo-1,3-β-glucanase) digest, OX-ZYM was found to contain 1,3-β-linked and 1,6-β-linked glucan moieties, while the latter degraded by sodium metaperiodate treatment. OX-ZYM also contained small amounts of anionic groups, partly reducible by sodium borohydride. Degree of polymerization (DP) of 1,6-β-glucan moiety was estimated to be about DP10–DP50 by MALDI-TOF-MS analysis. In comparison with ZYM activities, OX-ZYM and derivatives showed strong antitumor activity to solid form of Sarcoma 180 in mice, and showed strong activity on alternative pathway of complement, but lost secondary response to ZYM-immune mice. These facts strongly suggested that a particulate form of β-glucan was prepared by NaClO treatment of ZYM and at least a part of ZYM-mediated biological activity was found unmediated by β-glucan moiety.     

Enhancement of anti-tumor activity of gamma-irradiated silk fibroin via immunomodulatory effects

Silk fibers have proven to be effective in many clinical applications as well as for clothing. In addition to the substantial effect of silk fibers, the present study was conducted to explore its importance in a new dimension to reinforce the effects of its physiological function regarding anti-tumor activity and immune response with gamma-irradiated silk fibroin (GISF). The cytotoxicity results showed that pre-treatment of GISF in the mouse peritoneal macrophages (MPM) indicated a higher proliferative effect than that of non-irradiated silk fibroin (NISF) in a concentration-dependent manner. Based on the cytotoxicity result of MPM, GISF (50 and 150 kGy) was selected for an ex vivo study in an animal (C57BL6) system and evaluated about whether the non-specific immune response was also related to GISF. GISF (50 and 150 kGy) augmented immune responsiveness via activation of NK cells, T lymphocytes proliferation, NO production, and cytokine level, such as IL-6, IL-2, IL-12, IFN-γ, TNF-α, as compared with NISF, which strongly suggested that GISF significantly augmented an important element of all aspects of the innate and adaptive immune system. Therefore, from these results, it seems likely that the GISF will play a potent role in eliciting the effect of the non-specific immune response and anti-tumor activity as a value-added product in the medical industry.     

Different contributions of side-chains in β-d-(1 → 3,6)-galactans on intestinal Peyer’s patch-immunomodulation by polysaccharides from Astragalus mongholics Bunge

Thirteen polysaccharides isolated from an extract of the aerial portions of Astragalus mongholics Bunge demonstrated immunomodulating activity against Peyer’s patch immunocompetent cells. Nine of the active polysaccharide fractions were composed of either arabinogalactans, pectic arabinogalactans or pectins. The activities of the arabinogalactans and pectic arabinogalactans were associated with β-d-(1 → 3)-galactan moieties branched with β-d-(1 → 6)-galactooligosaccharide side-chains having degrees of polymerization of 8 or less. Degradation of the β-d-(1 → 3)-galactan or β-d-(1 → 6)-galactosyl side-chains in the arabinogalactans significantly decreased immunomodulating activity. Rhamnogalacturonan I (RG-I) with β-d-(1 → 3,6)-galactosyl side-chains having terminal β-d-GlcA showed activity in the pectin-enriched fractions. Interestingly, the terminal GlcA was not required for activity of the arabinogalactan-enriched fractions, suggesting at least two different immunomodulating structures.     

Characterization of Solubilized Products from the Cell Wall of Streptococcus pneumoniae during Autoplast Formation

The structure of the cell wall of Streptococcus pneumoniae R36a was investigated by means of chemical analysis of the solubilized products formed during autoplast formation. By autoplast formation, almost all of the cell wall components were solubilized as the end products within several hours. Analysis of the solubilized products revealed that the pneumococcal cell wall consists of three macromolecular components, teichoic acid-glycopeptide I (TA-GP I), teichoic acid-glycopeptide II (TA-GP II), and glycopeptide (GP III). The molecular size of TA-GP I was larger than that of TA-GP II. TA-GP I and TA-GP II were constituted of similar components, galactosamine, 2-acetamido-4-amino-2, 4, 6-trideoxyhexose, glucose, ribitol, choline, phosphate, and peptidoglycan components, but the ratio of teichoic acid to glycopeptide in TA-GP II was higher than that in TA-GP I. TA-GP II was solubilized more slowly than TA-GP I and GP III during autoplast formation. The assembly of the cell wall by TA-GP I and II, and GP III is discussed in connection with the action of autolysin.     

Obituary Fumio Oosawa 1922–2019

Prof. Fumio Oosawa passed away in Nagoya on March 4, 2019, at the age of 96. As two of his former students we, like a great many scientists both in Japan and around the world, were much inspired and influenced by him. We have, at the request of the journal, penned this note to describe some of his major scientific contributions and also provide the readers of Biophysical Reviews with an idea of the remarkable personality and character traits that he displayed throughout his life. Fumio Oosawa (or Oosawa-san as he preferred to be called) was a physicist who initially entered the area of biophysics through studies in the field of condensed matter phenomena. Although a remarkable human being, he was, first and foremost, one of the leading scientists of his generation, making many original contributions that could, by any measure, be described as scientific breakthroughs. Therefore, before providing a short biography of his life in and around science, we thought it most appropriate to begin this Letter by first summarizing his major scientific contributions.     

Characterization of complex formation between lipopolysaccharide and lysozyme

The binding of lysozyme (LZM) to bacterial lipopolysaccharide (LPS) inhibited the biological activities of LPS as well as the enzymic activity of LZM. The mode of binding has been characterized by using dansylated LZM and enzyme inhibition. The binding of LPS to LZM significantly increased the fluorescence intensity (Fl-intensity) of the danyl group and was found to be time-dependent; the complex was produced gradually and became stabilized within 20 min at 37 degrees, 10 min at 50 degrees, and 1 min at 70 degrees. The maximum level of binding was also dependent on the reaction temperature, and more complex was formed at higher temperatures. Complexation was strongly dependent on the salt concentration and was not observed at greater than 0.5M NaCl. From collected evidence of the Fl-intensities of various dansyl derivatives and amphiphiles, it is concluded that LZM interacts with LPS by multiple binding-modes, the first being strongly related to the enzyme inhibition, the second being close to the Fl-intensity, and the third being dependent on the inhibition of immunopharmacological activities. For the amphiphiles used in this study, sodium dodecyl sulfate (SDS), 3-[(3-cholamidopropyl)dimethylammonio]-1-propanesulfonate (CHAPS), 3-[(3-cholamidopropyl)dimethylammonio]-2-hydroxy-propanesulfonate (CHAPSO), decansulfonic acid, and cardiolipin have binding modes similar to that of LPS.     

Genotypic effects on the callus formation from different explants of rice,Oryza sativa L.

A total of 108 rice varieties were examined for their tissue culture responses. Callus tissues were initiated from the seed, radicle, coleoptile and anther explants. Our results indicated that genotypes differed in the ability to develop vigorously growing callus. The callus growth responses in seed, radicle and coleoptile cultures were intercorrelated, but were not correlated with that in anther culture.