Differences in vascular responses to vasoactive agents of basilar artery and aorta from rabbits with alloxan-induced diabetes.

Responses of the basilar artery and aorta to vasoactive agents in alloxan-induced diabetic and age-matched control rabbits were examined. There were no significant differences in the reactivity of the basilar artery to norepinephrine (NE), 5-hydroxytryptamine (5-HT), and K+ between age-matched control and diabetic rabbits. The maximal contraction of the aorta with endothelium in response to NE was significantly enhanced in the case of the aorta from diabetic rabbits. Pretreatment with 10(-6) M methylene blue or removal of the endothelium enhanced the contractile response of aorta to NE from control rabbits and, after such treatment, the concentration-response curve to NE was almost identical to that of aorta from diabetic rabbits. Basal levels of cyclic GMP but not cyclic AMP in the diabetic aorta with endothelium were significantly lower than those in the control aorta with endothelium. These results demonstrate that the cerebral artery is resistant to diabetes mellitus within 10 weeks as compared with the peripheral artery. The enhancement in the contractile response of aorta to NE in diabetic rabbits is due to the attenuation of the spontaneous release of endothelium-derived relaxing factor, through an impairment of the function of endothelial cells.     

Changes in responsiveness of the aorta to vasorelaxant agents in genetically diabetic rats: a study in WBN/Kob rats.

The effects of various vasorelaxant agents on aortas from control and genetically diabetic rats were examined. The concentration-response curves for the isoproterenol (ISO)-induced relaxation of both aortic strips with and without endothelium are shifted to the right in diabetic rats. The relaxation responses of diabetic aorta to forskolin and vasoactive intestinal peptide did not differ from those of controls. The relaxation responses of diabetic aorta to cromakalim and nicorandil did not differ from those of controls. These results indirectly indicate that ISO-induced relaxation responses of the aortic strips from genetically diabetic rats decreased, and that this decreased relaxation response of the strips to ISO may be due to decreased density or affinity of beta adrenoceptors on the endothelium and vascular smooth muscle.     

Use of 11alpha-deuterium labeled cortisol as a tracer for assessing reduced 11beta-HSD2 activity in vivo following glycyrrhetinic acid ingestion in a human subject

This study describes an oral administration of 5 mg of [1,2,4,19-13C4,11alpha-2H]cortisol (cortisol-13C4,2H1) to a human subject performed on two separate occasions, one with cortisol-13C4,2H1 alone and the other with cortisol-13C4,2H1 plus 130 mg per day of glycyrrhetinic acid for 6 days. The stable isotope methodology employed allowed for the evaluation of the individual in vivo activities of the two isozymes of 11beta-hydroxysteroid dehydrogenase (11beta-HSD), 11beta-HSD1 and 11beta-HSD2, and to demonstrate the sensitivity of changes in cortisol elimination half-life for detecting inhibition of 11beta-HSD2 activity induced with glycyrrhetinic acid. The kinetic analysis associated with the loss of 11alpha-2H during the conversion of cortisol-13C4,2H1 to cortisone-13C4 by 11beta-HSD2 clearly indicated reduced 11beta-HSD2 activity with glycyrrhetinic acid ingestion, as observed by an increase in the elimination half-life of cortisol-13C4,2H1. The elimination half-life of cortisol-13C4,2H1 provided sensitive in vivo measures of 11beta-HSD2 activity and was more sensitive for detecting changes in renal 11beta-HSD2 activity than the measurement of the urinary ratio of free cortisol and free cortisone (UFF/UFE). The 2H-labeling in the 11alpha-position of cortisol served as an appropriate tracer for assessing the reduced 11beta-HSD2 activity in vivo induced by glycyrrhetinic acid.     

Improvement of single nucleotide polymorphism genotyping by allele-specific PCR using primers modified with an ENA residue

When we placed an ENA residue into primers at the 3' end, or the n-1, n-2, or n-3 position, which included a single nucleotide polymorphism (SNP) site at the 3' end, only primers containing the ENA residue at the n-2 position were read by Taq DNA polymerase for amplification. The use of the ENA primers avoided the generation of undesired short products, which are thought to be derived from primer-dimers. A greater discrimination of the SNP site by these primers containing the ENA residue was observed compared with that of the corresponding unmodified DNA primers that are often used for allele-specific polymerase chain reaction (AS-PCR). This improvement is probably due to the difficulty of incorporating a nucleotide into the mismatched ENA primer by Taq DNA polymerase in the modified primer-template duplex. These results demonstrate that ENA primer-based AS-PCR would enable a rapid and reliable technique for SNP genotyping.     

Fluorous-tagged compound: a viable scaffold to prime oligosaccharide synthesis by cellular enzymes

Fluorous-tagged saccharide primers could be viable scaffolds for the synthesis of oligosaccharides. This research demonstrates that a fluorine-containing saccharide derivative could actually be taken up by the cell, the saccharide chain elongated by cellular enzymes, and the elongated product released by the cells to the culture medium. A fluorous-tagged lactoside primer, 6-(perfluorohexyl)hexyl-4-O-(beta-D-galactopyranosyl)-beta-D-glucopyranoside, was chemically synthesized and introduced in mouse B16 cells to prime oligosaccharide synthesis. Uptake of the primer by B16 cells resulted in the sialylation of the terminal galactose residue to afford an oligosaccharide with the same glycan structure as ganglioside GM3. The presence of many fluorine atoms did not have any adverse effects to the cells. Moreover, the number of fluorine atoms did not pose a steric barrier and instead, their presence possibly increased the hydrophobicity of the primer and enhanced membrane permeability. This strategy of using a fluorous-tagged primer and cells can pave the way for an easier way of preparing oligosaccharides via an environment-friendly approach that eliminates the use of large amounts of organic solvents.     

First record of habitat of Daulocoris formosanus (Hemiptera: Aradidae): Colonies discovered in nests of Salganea taiwanensis ryukyuanus (Dictyoptera: Blaberidae)

We collected colonies of Daulocoris formosanus from nests of the subsocial wood‐feeding cockroach Salganea taiwanensis ryukyuanus for the first time. To understand the ecology of D. formosanus, we observed and characterized their behavior in a laboratory setting. We provide the first detailed record of the habitat, colony structure and feeding behavior of D. formosanus.     

In vitro ectomycorrhizal formation in Picea glehnii seedlings

 Twenty isolates of ectomycorrhizal fungi – 3 from Picea glehnii, 12 from other coniferous trees, and 5 from decidous trees – were tested for the ability to form mycorrhizae with P. glehnii, using an in vitro synthesis technique. Macroscopically, mycorrhizal formation was observed 3 months after inoculation, when the lateral roots began to grow. Mycelial growth was observed in all inoculated treatments, generally around and along the roots. Six months after inoculation, seedlings were harvested and the mycorrhizae were observed microscopically. Fourteen of the 20 isolates formed ectomycorrhizae with a dense sheath and a deep Hartig net; 1 formed ectendomycorrhizae with a rudimentary mantle, a well-developed Hartig net and intracellular hyphae; 3 formed pseudomycorrhizae with a mantle but without the Hartig net; and only 2 of the fungi tested, Chalciporus pipeparatus 5/92 and Lyophyllum sp. 61/92, did not form mycorrhizae at all. P. glehnii was a good host species since it had low specificity to ectomycorrhizal fungi isolated from trees other than P. glehnii. Accepted: 6 May 1996     

CURRENT STATUS AND CONSERVATION NEEDS OF DUGONGS IN SOUTHERN JAPAN

We conducted aerial surveys of dugongs ( Dugong dugon ) using the line-transect method and snorkeling surveys of dugong feeding trails in 1998 and 1999 around Okinawa Island (26°30'N, 128°00'E) and the Sakishima Islands, southern Japan. A total of ten dugongs were sighted and feeding trails were confirmed in the sea grass beds off the east coast of Okinawa Island. In the Sakishima Islands, however, no dugongs were observed, and there was no evidence of feeding trails despite the existence of apparently suitable sea grass beds for feeding. The results of these surveys and other available information suggest that Okinawan dugongs represent a small, geographically isolated population. Our sightings of dugongs during the daytime, offshore of sea grass beds where feeding trails were recorded, suggest that Okinawan dugongs principally feed at night when human activities are limited. Survival of this remnant dugong population is threatened by habitat degradation and occasional entanglement mortality in fishing nets.     

Effect of inoculation of symbiotic fungi on the growth and antioxidant enzymes’ activities in the presence of <Emphasis Type="Italic">Fusarium subglutinans</Emphasis> f. sp. <Emphasis Type="Italic">ananas</Emphasis> in pineapple plantlets

The inoculation with symbiotic fungi, Arbuscular mycorrhizal fungi (AMF) and/or Piriformospora indica on the growth, nutrient absorption, and induction of antioxidant enzyme activities in plantlets of pineapple ‘Imperial’ (fusariosis-resistant) and ‘Pérola’ (fusariosis-susceptible) in the presence of Fusarium subglutinans f. sp. ananas was investigated. The experiment was comprised by two cultivars, with or without fungal inoculation (Claroideoglomus etunicatum, Rhizophagus clarus, and P. indica, a mixture of all the fungi, and the control—absence of fungal inoculation), with or without applying Fusarium conidia, and with four replicates. In both cultivars, nutrient absorption was higher in the AMF plantlets compared to those inoculated with P. indica or the control ones, although it was more efficient in ‘Imperial’ than in ‘Pérola’. Inoculation with AMF and/or P. indica as well as the pathogen influenced differently the activities of superoxide dismutase, catalase, glutathione reductase, peroxidase, and polyphenol oxidase, in the shoots or roots of pineapple plantlets in both cultivars. Inoculated plantlets with mixture of all the fungi also exhibited a better growth and nutrient absorption, and generally, the ‘Imperial’ responded better than ‘Pérola’. In addition, these plantlets developed better than the control even in the presence of pathogen, indicating that inoculation with AMF and/or P. indica may contribute to the production of more resistant propagative material. Increased antioxidant enzyme activity is a potential strategy for managing this plant for explore biological control as an alternative to reduce environmental and health impacts by reducing the use of fungicides.     

Activation of CMP-N-acetylneuraminic acid:lactosylceramide sialyltransferase during the differentiation of HL-60 cells induced by 12-O-tetradecanoylphorbol-13-acetate

We previously reported that the synthesis of NeuAc(alpha 2-3)Gal(beta 1-4)GlcCer (GM3) ganglioside was preferentially enhanced during the differentiation of HL-60 cells into a monocyte/macrophage lineage induced by 12-O-tetradecanoylphorbol-13-O-acetate (TPA). Since exogenously added GM3 ganglioside was shown to be able to induce the differentiation of HL-60 cells into the monocyte/macrophage lineage in a synthetic medium, the functional role of the GM3 ganglioside increase during the differentiation of HL-60 cells has become the subject of much interest. In the present study, we investigated the activity of CMP-NeuAc:lactosylceramide sialyltransferase, which catalyzes the synthesis of GM3 ganglioside from lactosylceramide, in cells undergoing differentiation induced by two different reagents, TPA and 1 alpha,25-dihydroxy-vitamin D3, which induce the differentiation of HL-60 cells into the monocyte/macrophage lineage through different modes of action. We showed that the activation of CMP-NeuAc:lactosylceramide sialyltransferase and the increase in GM3 ganglioside were not related to the differentiated lineage but to the specific action of TPA, i.e. activation of protein kinase C.