A new type of 3‐D peripheral ultrastructure in Glaucocystis (Glaucocystales,Glaucophyta) as revealed by ultra‐high voltage electron microscopy

The coccoid glaucophyte genus Glaucocystis is characterized by having a thick cell wall, which has to date prohibited examination of the native ultrastructural features of the protoplast periphery. Recently, however, the three‐dimensional (3‐D) ultrastructure of the protoplast periphery was revealed in two divergent Glaucocystis species, with the world's most powerful ultra‐high voltage electron microscope (UHVEM). The two species exhibit morphological diversity in terms of their 3‐D ultrastructural features. However, these two types do not seem to encompass actual ultrastructural diversity in the genetically diverse genus Glaucocystis. Here, we report a new type of peripheral 3‐D ultrastructure resolved in “G. incrassata” SAG 229‐2 cells by 3‐D modeling based on UHVEM tomography using high‐pressure freezing and freeze‐substitution fixation. The plasma membrane and underlying flattened vesicles in “G. incrassata” SAG 229‐2 exhibited grooves at intervals of 200–600 nm, and the flattened vesicles often overlapped one another at the protoplast periphery. This 3‐D ultrastructure differs from those of the two types previously reported in other species of Glaucocystis. The possibility of classification of Glaucocystis species based on the 3‐D ultrastructure of the protoplast periphery is discussed.     

In vitro formation of the Merkel cell‐neurite complex in embryonic mouse whiskers using organotypic co‐cultures

A Merkel cell‐neurite complex is a touch receptor composed of specialized epithelial cells named Merkel cells and peripheral sensory nerves in the skin. Merkel cells are found in touch‐sensitive skin components including whisker follicles. The nerve fibers that innervate Merkel cells of a whisker follicle extend from the maxillary branch of the trigeminal ganglion. Whiskers as a sensory organ attribute to the complicated architecture of the Merkel cell‐neurite complex, and therefore it is intriguing how the structure is formed. However, observing the dynamic process of the formation of a Merkel cell‐neurite complex in whiskers during embryonic development is still difficult. In this study, we tried to develop an organotypic co‐culture method of a whisker pad and a trigeminal ganglion explant to form the Merkel cell‐neurite complex in vitro. We initially developed two distinct culture methods of a single whisker row and a trigeminal ganglion explant, and then combined them. By dissecting and cultivating a single row from a whisker pad, the morphogenesis of whisker follicles could be observed under a microscope. After the co‐cultivation of the whisker row with a trigeminal ganglion explant, a Merkel cell‐neurite complex composed of Merkel cells, which were positive for both cytokeratin 8 and SOX2, Neurofilament‐H‐positive trigeminal nerve fibers and Schwann cells expressing Nestin, SOX2 and SOX10 was observed via immunohistochemical analyses. These results suggest that the process for the formation of a Merkel cell‐neurite complex can be observed under a microscope using our organotypic co‐culture method.     

Dietary astaxanthin can accumulate in the brain of rats

We evaluated the distribution of astaxanthin in rat brains after a single dose administration and after feeding 0.1% astaxanthin diet for 5 days. Astaxanthin was detected in the hippocampus and cerebral cortex 4 and 8 h after a single dose. Astaxanthin concentration in rat brains was higher after consumption of astaxanthin diet for 5 days than after a single dose.     

Growth variability of juvenile skipjack tuna (<Emphasis Type="Italic">Katsuwonus pelamis</Emphasis>) in the western and central Pacific Ocean

We examined growth rates of juvenile skipjack tuna using otolith daily increment analysis to clarify geographic differences in early-life stage growth in the western and central Pacific Ocean (WCPO). We used a liner regression model to analyze the relationship between standard length (SL) and age (in days). The slope of growth model was significant difference between regions. There were rapid increases in the otolith mean daily increment width of juveniles at 7 days after hatching (DAH) and 10 DAH in the Western Pacific Warm Pool (WARM) and North Pacific Tropical Gyre area (NPTG), respectively. These periods correspond to the timing at which larvae complete their digestive-system development and start the piscivory. We found significant difference in logarithmic back-calculated SL between WARM and NPTG at 3 DAH (p?<?0.01). Mean growth rates until 10 DAH, when the larvae metamorphose into juveniles, were positively correlated with sea surface temperature (r?=?0.52). These results indicate that geographic difference in the growth of juvenile skipjack tuna caught in the WCPO in boreal winter cause in the larval stage, and that these differences are related to sea surface temperature.     

Selective incorporation of various C-22 polyunsaturated fatty acids in Ehrlich ascites tumor cells

Three 14C-labeled 22-carbon polyunsaturated fatty acids, 7,10,13,16-[14C]docosatetraenoic acid (22:4(n-6)), 7,10,13,16,19-[14C]docosapentaenoic acid (22:5(n-3)), and 4,7,10,13,16,19-[14C]docosahexaenoic acid (22:6(n-3)), were compared with [3H]arachidonic acid (20:4(n-6] and [14C]linoleic acid (18:2(n-6)) to characterize their incorporation into the lipids of Ehrlich ascites cells. The relatively rapid incorporation of the labeled 22-carbon acids into phosphatidic acid indicated that substantial amounts of these acids may be incorporated through the de novo pathway of phospholipid synthesis. In marked contrast to 20:4(n-6), the 22-carbon acids were incorporated much less into choline glycerophospholipids (CGP) and inositol glycerophospholipids (IGP). No selective preference was apparent for the (n-3) or (n-6) type of fatty acids. The amounts of the acids incorporated into diacylglycerophosphoethanolamine were in the order of: 22:6(n-3) greater than 20:4(n-6) much greater than 22:5(n-3) greater than or equal to 22:4(n-6) greater than 18:2(n-6), whereas for alkylacylglycerophosphoethanolamine they were in the order of: 22:4(n-6) greater than 22:6(n-3) greater than 22:5(n-3) much greater than 20:4(n-6) greater than 18:2(n-6). Of the mechanisms possibly responsible for the selective entry of 22-carbon acids into ethanolamine glycerophospholipids, the most reasonable explanation was that the cytidine-mediated ethanolamine phosphotransferase may have a unique double selectivity: for hexaenoic species of diacylglycerol and for 22-carbon polyunsaturated fatty acid-containing species of alkylacylglycerol. The relative distribution of fatty acids between newly incorporated and already maintained lipid classes suggested that IGP may function in Ehrlich cells as an intermediate pool for the retention of polyunsaturated fatty acids in glycerolipids.     

Transplantation of the rat pineal organ to the brain: pinealocyte differentiation and innervation

Summary The pineal organ of neonatal rats was transplanted to the frontal part of the cerebral cortex or the cerebral interhemispheric fissure of an isogenic adult rat to determine whether pineal differentiation and pinealopetal innervation are affected by aberrant neuronal influences. Transplants were fixed for immunohistochemistry at 1, 2 and 6 months after transplantation. When treated with an anti-serotonin antibody, cells in transplants from both locations showed intense immunoreactivity and a morphology comparable to intact pinealocytes, indicating that the transplanted pinealocytes had differentiated normally. Tyrosine hydroxylase immunohistochemistry revealed that new catecholamine fibers of central nervous origin extended only into the periphery and not into the core of transplants grafted within the cortex. However, numerous catecholamine fibers were found in transplants placed in the interhemispheric fissure. These fibers were often accompanied by blood vessels, suggesting that they derived from sympathetic ganglia. Serotonin fibers, which are densely distributed in the cerebral cortex, were seldom found to enter transplants from both locations. These observations indicate that pineal cells express their characteristic properties even when transferred to a foreign milieu and that they do not receive novel innervation from the central nerves that normally do not innervate the intact pineal body; the transplant thereby retains the property of selective pinealopetal innervation.     

Significant prolongation of disease-free period gained by oral polysaccharide K (PSK) administration after curative surgical operation of colorectal cancer

Summary To examine the clinical efficacy and the mechanism of action of polysaccharide K (PSK), a proteinbound polysaccharide extracted from a Basidiomycetes fungus, a randomized double-blind trial was performed by administering PSK to 56 patients and a placebo to another group of 55 patients after surgical operations on their colorectal cancers. The rate of patients in remission (or disease-free) was significantly higher in the PSK group than in the placebo group; the difference between both groups was statistically significant atP <0.05 by the logrank test. The survival rate of patients was also significantly (P <0.05) higher in the PSK group than in the control group. The most significant laboratory finding was that polymorphonuclear leukocytes from PSK-treated patients showed remarkable enhancement in their activities, such as random and/or chemotactic locomotion, and phagocytic activity, when compared with those in the control group. In conclusion, PSK was useful as a maintenance therapy for patients after their curative surgical operations for colorectal cancer. The beneficial effects were probably due to the activation of leukocyte functions as one of the many biological-response-modifying (activities induced by PSK).     

Estimation of chronological age for sporophyte maturation in three semi-evergreen ferns in Hokkaido

To elucidate the life cycle time schedule of semi-evergreen ferns at natural sites in Sapporo, the chronological age for sporophyte maturation was estimated from the increase in the number of veins (NV, number of midrib branches) from overwintered to newly expanded leaves. The measurements were conducted on populations ofPolystichum braunii, Polystichum tripteron andDryopteris crassirhizoma at altitudes of 50–650 m on Mt. Teine to compare the interspecific maturation age of sporophytes. The mean age for sporophyte maturation was estimated to be 7.6 yr forP. braunii, 16.5 yr forP. tripteron and 12.6 yr forD. crassirhizoma. The minimum ages (1% fertility rate) for sporophyte maturation ofP. braunii, P. tripteron andD. crassirhizoma were 5.8, 11.0 and 7.9 yr, respectively. The maturation age was shortest forP. braunii and longest forP. tripteron. The maturation age of a species thus seems to differ according to altitude and habitat, and that of the present three species seems to be influenced by the geographical location of the species distribution. Contribution No. 3315 from the Institute of Low Temperature Science, Hokkaido University.     

Eimeria tenella,E. necatrix,E. acervulina,and E. maxima: Anticoccidial activity of 1,6-dihydro-6-oxo-2-pyrazinecarboxylic acid 4-oxide

The anticoccidial activity of an orotic acid analog, 1,6-dihydro-6-oxo-2-pyrazinecarboxylic acid 4-oxide (carboxyemimycin), was tested in battery experiments, utilizing 9-day-old Single-Comb White Leghorn cockerels. Carboxyemimycin, at 125 ppm and more in feed, exhibited marked anticoccidial activities against Eimeria tenella, E. necatrix, E. acervulina, and E. maxima. High doses of carboxyemimycin—up to 1000 ppm—did not cause any reduction in weight gains. The battery and in vitro studies with delayed and restricted medications revealed that carboxyemimycin affected the development of E. tenella in first and second generation schizogony and in gametogony.     

Overexpression of Peroxiredoxin 4 Affects Intestinal Function in a Dietary Mouse Model of Nonalcoholic Fatty Liver Disease

BackgroundAccumulating evidence has shown that methionine- and choline-deficient high fat (MCD+HF) diet induces the development of nonalcoholic fatty liver disease (NAFLD), in which elevated reactive oxygen species play a crucial role. We have reported that peroxiredoxin 4 (PRDX4), a unique secretory member of the PRDX antioxidant family, protects against NAFLD progression. However, the detailed mechanism and potential effects on the intestinal function still remain unclear.ConclusionOur present data provide the first evidence of the beneficial effects of PRDX4 on intestinal function in the reduction of the severity of NAFLD, by ameliorating oxidative stress-induced local and systemic injury. We can suggest that both liver and intestine are spared, to some degree, by the antioxidant properties of PRDX4.