A cnidarian neuropeptide of the GLWamide family induces metamorphosis of reef-building corals in the genus <Emphasis Type="Italic">Acropora</Emphasis>

Coral larvae appear to sense appropriate environments for settlement and start metamorphosis by converting external cues into internal signals, although little is known about these molecular mechanisms. A family of neuropeptides, GLWamides, are thought to be such internal signals, acting hormonally to induce metamorphosis in some hydrozoan species. Here we report that one member of the GLWamide peptide family, Hym-248, can induce metamorphosis of planula larvae in the genus Acropora. The Acropora planulae responded to the peptide in a concentration-dependent manner. The GLWamide peptide would mimic endogenous molecules to start metamorphosis in Acropora as in case of hydrozoans. In addition, the peptide could be applied to produce "coral seedlings" with the aim of reef restoration.     

Design, synthesis and biological activity of novel C2-C3' N-Linked macrocyclic taxoids

A series of novel macrocyclic taxoids was designed and synthesized by connecting the C-2 and C-3' N positions of the taxoid framework with various tethers. Cytotoxicity of these macrocyclic taxoids was evaluated against a human breast cancer cell line LCC6-WT, and a couple of the taxoids exhibited 0.09-0.3 microM IC(50) values.     

Establishment of conditionally immortalized rat retinal pericyte cell lines (TR-rPCT) and their application in a co-culture system using retinal capillary endothelial cell line (TR-iBRB2)

The purpose of this study was to establish and characterize a retinal pericyte cell line from retinal capillaries of transgenic rats harboring the temperature-sensitive simian virus 40 large T-antigen gene (tsA58 Tg rat), and to apply this to the co-culture with a retinal capillary endothelial cell line. The conditionally immortalized rat retinal pericyte cell lines (TR-rPCTs), which express a temperature-sensitive large T-antigen, were obtained from two tsA58 Tg rats. These cell lines had a multicellular nodule morphology and reacted positively with von Kossa staining, a marker of calcification. TR-rPCTs cells expressed mRNA of pericyte markers such as rat intercellular adhesion molecule-1, platelet-derived growth factor-receptor beta, angiopoietin-1, and osteopontin. Western blot analysis indicated that alpha-smooth muscle actin (alpha-SMA) was expressed in TR-rPCT3 and 4 cells. In contrast, alpha-SMA was induced by transforming growth factor-beta1 and its enhancement was reduced by basic fibroblast growth factor in TR-rPCT1 and 2 cells. When TR-rPCT1 cells were cultured with a rat retinal endothelial cell line (TR-iBRB2) in a contact co-culture system, the number of TR-iBRB2 cells were significantly reduced in comparison with that of a single culture of TR-iBRB2 cells, suggesting that physical contact between pericytes and retinal endothelial cells is important for the growth of retinal endothelial cells. In conclusion, conditionally immortalized retinal pericyte cell lines were established from tsA58 Tg rats. These cell lines exhibited the properties of retinal pericytes and can be applied in co-culture systems with a retinal capillary endothelial cell line.     

Long-term treatment with glibenclamide increases susceptibility of streptozotocin-induced diabetic rat heart to reperfusion-induced ventricular tachycardia

This study investigated the effects of long-term treatment with glibenclamide (GLIB) on the susceptibility of streptozotocin (STZ)-induced diabetic heart to ischemia/reperfusion insults. Starting 4 weeks after the injection of STZ, rats were treated with GLIB (0.1 mg/kg, ip, three times a week, STZ-GLIB group) or vehicle (STZ-VEH group) for 8 weeks. The recovery of cardiac performance, released creatine kinase (CK), and incidence of ventricular arrhythmias were studied during the reperfusion period in isolated hearts from rats in STZ-GLIB (n = 14) and in STZ-VEH groups (n = 13) and from age-matched control rats (CNT group, n = 14). Each heart was subjected to 5 min of global low-flow ischemia followed by 25 min of no-flow ischemia, with a subsequent 30 min of reperfusion. Plasma glucose level was not significantly different between the STZ-GLIB and STZ-VEH groups. The recovery of cardiac performance and the released CK during reperfusion period were significantly lower in both STZ-VEH and STZ-GLIB groups than in the CNT group (P < 0.01 and P < 0.05, respectively). Reperfusion resulted in an incidence of ventricular fibrillation in 23% and 21% in STZ-VEH and STZ-GLIB groups, respectively (P = ns). These values were significantly lower than that of the CNT group (100%, P < 0.001 for both). More importantly, the incidence of ventricular tachycardia in the STZ-GLIB group was significantly higher than that in the STZ-VEH group (93% vs 54%, P < 0.05) and was not significantly different from that in the CNT group (93% vs 100%, P = ns). The results suggest that STZ-induced protection against reperfusion-induced ventricular arrhythmias in diabetic heart may be partially abrogated by long-term treatment with GLIB.     

Isolation of a novel thermophilic fungus <Emphasis Type="Italic">Chaetomium</Emphasis> sp. nov. MS-017 and description of its palm-oil mill fiber-decomposing properties

Palm-oil mill fiber (POMF) is a fibrous, natural hard material discharged in enormous amounts from palm-oil mills in tropical plantations; therefore, research to find microorganisms that decompose POMF was conducted. As the result of screening, a new thermophilic fungus, Chaetomium sp. nov. MS-017, exhibiting rapid growth on POMF was isolated from rotted wood. Based on partial characterization of the decomposition of POMF, it was shown that MS-017 preferentially assimilates polysaccharides, especially hemicelluloses such as xylan. A preliminary composting study indicated that MS-017 produced 855 g of decomposed product from 1,000 g of intact POMF in 12 days under optimized solid-culture conditions. The decomposition rate of POMF was 23% (w/w), and the cell yield calculated from consumed POMF was as high as 36% (w/w). These results indicate that MS-017 has a very high potential to decompose POMF and that it is suitable for economical production of compost to recycle by-product biomass from oil-palm plantations.     

Mitochondrial membrane potential and intracellular ATP content after transient experimental ischemia in the cultured hippocampal neuron

Ischemia limits the delivery of oxygen and glucose to cells and disturbs the maintenance of mitochondrial membrane potential (MMP). MMP regulates the production of high-energy phosphate and apoptotic cascading. Thus, MMP is an important parameter determining the fate of neurons. Differences in the time course of MMP according to the grading of the ischemic impact have not been clarified. MMP and intracellular ATP contents were monitored before and after short-term oxygen-glucose deprivation. A primary hippocampal culture seeded in a 35 mm fenestrated dish for fluorescence microscopy was mounted in a sealed chamber for an anaerobic incubation. A continuous flow of 100% nitrogen into the chamber and a replacement of glucose-free medium allowed the condition of oxygen-glucose deprivation (OGD), thereby extrapolating ischemia. MMP was evaluated by the fluorescence of a voltage-dependent dye, JC-1, under fluorescence microscopy. The intracellular ATP content was evaluated in a hippocampal culture seeded in a 96-well plate by the luciferin-luciferase reaction after a designated period of OGD. During OGD, MMP decreased to 0.72+/-0.03 (normalized JC-1 fluorescence), then increased to the hyperpolarized level 1.99+/-0.12 during 60 min reoxygenation after 30 min OGD. MMP after 60 min OGD decreased and recovered occasionally during reoxygenation. After 90 min OGD and reoxygenation, MMP was reduced and never recovered. The intracellular ATP content was 8.1+/-6.6 and 3.2+/-1.9% after 30 min OGD and 30 min reoxygenation following 30 min OGD, respectively; 60 min OGD did not significantly change these levels (7.1+/-5.8, 2.6+/-0.5%). Hyperpolarization after OGD did not accompany ATP production. This observation suggests the inhibition of electron reentry into an inner membrane during reoxygenation and the disturbance of FoF1-ATP synthase. This pathological finding of an energy-producing system after OGD may provide a clue to explain post-ischemic energy failure.     

Inhibition of recombinant dipeptidyl peptidase III by synthetic hemorphin-like peptides

In order to find the most effective antagonist for dipeptidyl peptidase III degrading enkephalin, we synthesized hemorphin-like pentapeptides with aliphatic or aromatic amino acids at the N-termini, such as VVYPW, LVYPW, IVYPW, YVYPW, FVYPW and WVYPW. Among those pentapeptides, IVYPW and WVYPW showed the strongest inhibitory activity toward rDPP III. The K(i) values of IVYPW and WVYPW were 0.100+/-0.011 and 0.126+/-0.015 microM (mean+/-S.E.), respectively. The order of K(i) values was Ile> or =Trp>Phe> or =Tyr>Leu>Ala>Val>Ser>Gly. rDPP III activity is inhibited in a non-competitive manner by these peptides. The peptide VYPW did not inhibit rDPP III activity, but the sequence is essential for the expression of inhibitory activity.