Decrease in uptake of arachidonic acid by indomethacin in LS174T human colon cancer cells; a novel cyclooxygenase-2-inhibition-independent effect

Nonsteroidal anti-inflammatory drugs (NSAIDs) have chemopreventive activity and may be suitable for treatment of colorectal cancer. A popular and potent NSAID, indomethacin, is known to cause serious side-effects, for this reason its therapeutic usefulness is limited. However, these side-effects are likely to be attributed to the additional effects of indomethacin besides its cyclooxygenase inhibition. In this study, we examined the effect of indomethacin on arachidonic acid uptake using LS174T human colon cancer cells. We here show that treatment of LS174T cells with indomethacin reduced arachidonic acid uptake as well as reduced expressions of fatty acid translocase/CD36 and peroxisome proliferators-activated receptor γ. Since arachidonic acid is a major substrate of inflammatory mediators such as prostaglandins and leukotrienes, we believe this novel effect of indomethacin may apply to new treatment strategies that aim to suppress these mediators by decreasing the uptake of their substrates, which would eventually inhibit colorectal cancer malignancy.     

Relationships between release season and feeding performance of hatchery-reared Japanese flounder Paralichthys olivaceus: In situ release experiment in coastal area of Wakasa Bay, Sea of Japan

Two groups of hatchery-reared juveniles of Japanese flounder Paralichthys olivaceus (Temminck and Shlegel) were experimentally released in Wada Beach, Fukui Prefecture, Japan and their feeding state examined in comparison to wild juveniles to investigate the optimal release season and the relationship between food availability and feeding performance of juveniles. We released two groups of 40,000 juveniles of ca. 50 mm size, one group in the early (29 May) and the other in late (2 July) seasons, periods with predicted high and low densities of prey mysids, respectively, although the abundance of mysids fluctuated markedly during the season. Food availability was higher for the early release group than the late release group. Although the main stomach contents of released and wild juveniles were mainly mysids and fish, the feeding state differed between the early and late release groups. The early release group had a stomach content index (SI) similar to that of the wild juveniles, but the SI of the late group was significantly less than that of the early release group and wild juveniles. The percentage of fish with empty stomachs was much higher in the late release group than in the other two groups. In addition, the density decrease rate was significantly more rapid for the late release group than the early release group. Clear correspondence between the food availability and feeding state of the released flounder juveniles indicates that the release of juveniles in an appropriate season when mysids are abundant is crucial for successful stocking.     

Excitable Signal Transduction Induces Both Spontaneous and Directional Cell Asymmetries in the Phosphatidylinositol Lipid Signaling System for Eukaryotic Chemotaxis

Intracellular asymmetry in the signaling network works as a compass to navigate eukaryotic chemotaxis in response to guidance cues. Although the compass variable can be derived from a self-organization dynamics, such as excitability, the responsible mechanism remains to be clarified. Here, we analyzed the spatiotemporal dynamics of the phosphatidylinositol 3,4,5-trisphosphate (PtdInsP3) pathway, which is crucial for chemotaxis. We show that spontaneous activation of PtdInsP3-enriched domains is generated by an intrinsic excitable system. Formation of the same signal domain could be triggered by various perturbations, such as short impulse perturbations that triggered the activation of intrinsic dynamics to form signal domains. We also observed the refractory behavior exhibited in typical excitable systems. We show that the chemotactic response of PtdInsP3 involves biasing the spontaneous excitation to orient the activation site toward the chemoattractant. Thus, this biased excitability embodies the compass variable that is responsible for both random cell migration and biased random walk. Our finding may explain how cells achieve high sensitivity to and robust coordination of the downstream activation that allows chemotactic behavior in the noisy environment outside and inside the cells.     

Physiological Studies on Thiobacilli

Thiosulfate was oxidized to tetrathionate and an unknown oxidized sulfur compound. The activity was found in the particulate fraction (a precipitate obtained by centrifuging (at 90,000 × g for 60 min) the supernatant of centrifugation at 10,000 × g for 30 min). Treatment with deoxycholate caused inactivation of the enzyme. Considering from these points and electronmicrograph, the enzyme would be located on the cell membrane.     

Autotomy and arm number increase in Oxycomanthus japonicus (Echinodermata, Crinoidea)

Abstract. We have explored the process by which crinoids increase arm number as they grow. Two hypotheses have been proposed: (1) arm autotomy with subsequent bifurcation and regeneration of a pair of arms, and (2) growth of a pinnule into an additional arm. We have traced the development of Oxycomanthus japonicus for about a year after fertilization and provide the first confirmation that the number of arms increases by autotomy, bifurcation, and subsequent regeneration of a pair of arms. The next such addition tends to occur at some distance from the previous pair. Thus, increase of arm number takes place in such a manner that the density of the arms remains relatively constant, and an efficient filtration fan for feeding is maintained. Although arm autotomy in crinoids has been considered to occur only as a response to physical or chemical disturbance, the present results suggest that autotomy also occurs as a specific, intrinsically programmed event during normal development.     

Zaragozic acids production from discomycetes

In search for new zaragozic acids and their derivatives that are potent inhibitors of squalene synthase, discomycetes of the order Leotiales were cultured and their fermentation broth was assayed. Three strains in 2 unidentified species ofMollisia were found to produce zaragozic acid D3 and three new analogs (F-10863s). Fermentative production, productivity of F-10863s and mycological characteristics of the producers are described. Discomycetes are expected to be a biological resource providing novel bioactive compounds.