Sulfate and Nitrate Loads on a Forest Ecosystem in Kochi in Southwest of Japan

To assess the influence of acidic deposition on the forest ecosystem, it is necessary to evaluate the gross amount of acidic deposition. In this paper, we discuss the variation of sulfate (SO₄ ^2?) and nitrate (NO₃ ^?) loads as well as related concentration from 1991 to 1999 in the Hinoki (Chamaecyparis obtusa) plantation in Kochi, southwest Japan. The annual precipitation varied significantly from 1,700 to 3,900 mm during the study period. The annual sulfate concentration of rainfall was about 15 µmol L^?1, including about 80% non sea salt sulfate, while the annual nitrate concentration of rainfall was increased. The sulfate and nitrate concentrations of the through fall and the nitrate concentration of the stem flow were equal to or slightly higher than those of rainfall. However, the sulfate concentration of the stem flow was higher than that of rainfall, 21 to 55 µmol L^?1. The sulfate and nitrate loads of rainfall were measured to be 27 to 46 and 14 to 43 mmol m^?2 y^?1, respectively. The sulfate and nitrate loads of the through fall were the same or slightly higher than those of rainfall. In contrast, the sulfate and nitrate loads of the stem flow were less than those of rainfall. Combined sulfate loads of the through fall and the stem flow reached about 1.5 times that of the sulfate load of rainfall.     

Antioxidant activity of prune (Prunus domestica L.) constituents and a new synergist

Ethanol extract of prune was separated into hexane-soluble and H(2)O-soluble fractions, and the H(2)O-soluble fraction was further separated into a methanol (MeOH) eluate and an H(2)O eluate by Diaion HP-20 column chromatography. The MeOH eluate exhibited the strongest antioxidant activity among the separated fractions evaluated by oxygen radical absorbance capacity (ORAC). Further purification of the MeOH eluate led to isolation of a novel compound, 4-amino-4-carboxychroman-2-one, together with four known compounds (p-coumaric acid, vanillic acid beta-glucoside, protocatechuic acid, and caffeic acid), structures of which were identified by NMR and MS analyses. The ORAC values of these isolated compounds showed 0.15-1.43 units (micromol of Trolox equiv)/micromol, and the new compound showed a remarkable synergistic effect on caffeoylquinic acid isomers. The antioxidant activity of the MeOH eluate was highly dependent on the major prune components, caffeoylquinic acid isomers, with a contribution from the new synergist.     

Application of α-glucosidase activity and drug susceptibility tests to epidemiological studies on the fish pathogen <Emphasis Type="Italic">Nocardia seriolae</Emphasis>

This study determined the minimum inhibitory concentrations (MICs) for oxytetracycline hydrochloride (OTC) and erythromycin (Em), along with the α-glucosidase (α-glu) activities in 110 Nocardia seriolae strains isolated in Miyazaki and Kagoshima prefectures in 2008–2009. The strains were examined for the presence of the tet(K), tet(L), tet(M), tet(O), tet(S), erm(A), erm(B), mph(A), mef(A), and msr(D) genes. All the α-glu-positive strains (n = 15) were OTC resistant and Em sensitive, with MICs of 32–64 and <0.125 μg/ml, respectively. All the α-glu-negative strains (n = 95) were OTC sensitive, with MICs of 2–4 μg/ml, and most of them (93 of 95) were Em resistant, with MICs of >128 μg/ml. The MICs for Em in the remaining 2 α-glu-negative strains were <0.125 μg/ml. The 15 OTC-resistant strains possessed the tet(K) and/or tet(L) gene(s), and all of the 93 Em-resistant strains possessed both the mef(A) and msr(D) genes. The relationship between α-glu activity and drug sensitivity of the N. seriolae strains may explain the difference in prevalence of each phenotype. Nevertheless, the relationship should be further explored using N. seriolae isolates collected from more prefectures and farms.     

Central somatostatin-somatostatin receptor 2 signaling mediates lactational suppression of luteinizing hormone release via the inhibition of glutamatergic interneurons during late lactation in rats

Reproductive function is suppressed during lactation owing to the suckling-induced suppression of the kisspeptin gene (Kiss1) expression in the arcuate nucleus (ARC) and subsequent suppression of luteinizing hormone (LH) release. Our previous study revealed that somatostatin (SST) neurons mediate suckling-induced suppression of LH release via SST receptor 2 (SSTR2) in ovariectomized lactating rats during early lactation. This study examined whether central SST-SSTR2 signaling mediates the inhibition of ARC Kiss1 expression and LH release in lactating rats during late lactation and whether the inhibition of glutamatergic neurons, stimulators of LH release, is involved in the suppression of LH release mediated by central SST-SSTR2 signaling in lactating rats. A central injection of the SSTR2 antagonist CYN154806 (CYN) significantly increased ARC Kiss1 expression in lactating rats on day 16 of lactation. Dual in situ hybridization revealed that few ARC Kiss1-positive cells co-expressed Sstr2, and some of the ARC Slc17a6 (a glutamatergic neuronal marker)-positive cells co-expressed Sstr2. Furthermore, almost all ARC Kiss1-positive cells co-expressed Grin1, a subunit of N-methyl-D-aspartate (NMDA) receptors. The numbers of Slc17a6/Sstr2 double-labeled and Slc17a6 single-labeled cells were significantly lower in lactating dams than in non-lactating rats whose pups had been removed after parturition. A central injection of an NMDA antagonist reversed the CYN-induced increase in LH release in lactating rats. Overall, these results suggest that central SST-SSTR2 signaling, at least partly, mediates the suppression of ARC Kiss1 expression and LH release by inhibiting ARC glutamatergic interneurons in lactating rats.     

Effect of gestational exposure to nonylphenol on the development and fertility of mouse offspring

Nonylphenol (NP), a kind of environmental chemical, is thought to imitate endogenous hormones, inhibit the actions of hormones, and induce reproductive abnormalities. A number of experimental animals, usually rats, have been used to evaluate the potential reproductive toxicity of NP. However, the findings of previous studies were contradictory in some cases. Therefore, we used ICR mice as a biomodel for in utero study of NP. After mating, 8- to 12-week-old females were assigned to four groups (n=8) for subcutaneous injections from day 5 to 20 of gestation. Group I animals received corn oil alone as a control, while the mice of groups II, III and IV received NP at concentrations of 1/1000, 1/100 and 1/10 of the LD(50), respectively. A dose-dependent decrease was observed in terminal body weights of males of the F1 generation; however, a very small negative effect was only found in the females of the NP1/10 group. No significant effect was found on the liver weights of both sexes. The weights of the testis and epididymis were slightly decreased in the NP1/10 group. The NP1/100 treatment increased ovary weight considerably. The uterus weight tended to be increased in the NP treatment groups; however, there were large variations. The gestational exposure of the groups had no significant effect on the rate of pregnancy (94.4-100%) and the number of fetuses per litter (13.6-14.3 males, 12.3-13.7 females) compared with the control group. However, the overall mortality of fetuses/embryos was increased considerably in the NP1/100 (male: 13.9%) and NP1/10 (female: 9.8%) groups. These results suggest that exposure to NP in utero possibly affects the body weight and some reproductive organ weights, but does not influence the potential fertility of the F1 generation.     

Inhibition of post-mortem muscle softening following in situ perfusion of protease inhibitors in tilapia

ABSTRACT:     A method of introducing protease inhibitors into fish muscle through the bulbus arteriosus was developed using an in situ perfusion technique. Perfusion efficiency was initially tested using eosin and [³⁵S]-methionine. Visible fluorescence was observed in the gill, liver, intestine and dorsal muscle of the eosin-treated tilapia, and the occurrence of eosin in the blood vessels of the dorsal muscle was confirmed under a fluorescence stereoscopic microscope with ultraviolet light. The radioactivity of [³⁵S]-methionine was taken into the dorsal muscle and liver at a concentration of 7.8 Bq/g and 70.2 Bq/g, respectively, after perfusion with 1000 Bq/mL solution. Using the perfusion technique with four kinds of protease inhibitors dissolved in physiological saline, the type of proteases implicated in the post-mortem muscle softening in tilapia (867 ± 195 g, n  = 10/protease inhibitor) was investigated. After the perfusion of leupeptin (serine and cysteine protease inhibitor), benzyloxycarbonyl-Val-Ala-Asp-fluoromethylketone (Z-VAD-fmk; caspase inhibitor), chymostatin (serine protease inhibitor) and ο -phenanthroline (metalloprotease inhibitor), the breaking strength of the perfused muscle was measured as a parameter of the meat toughness and compared with that of the control fish, which were perfused with physiological saline only. The reduction of breaking strength during storage was inhibited by the perfusion of leupeptin and Z-VAD-fmk.     

Avian adenovirus isolated from pigeons affected with inclusion body hepatitis

Avian adenoviruses were isolated from two pigeons affected with inclusion body hepatitis (IBH) by using chicken embryo liver cell cultures. One of the isolates, designated strain S-PL1, replicated in the cell nuclei forming intranuclear inclusion bodies, showed adenovirus-like morphology by electron microscopy, and cross-reacted serologically with strain SR-48 known as serotype 2 of fowl adenovirus. The strain S-PL1 killed day-old chicks by subcutaneous inoculation, and its 50% chicken lethal dose was 10(3.8) plaque forming units per bird. Severe lesions characterized with IBH and pancreatitis, were produced in chicks inoculated with the virus. Intranuclear inclusion bodies were also recognized in the liver, pancreas, kidney, proventriculus, small intestine, and caecum. By indirect immunofluorescence test, intranuclear viral antigens were detected in the liver, pancreas and other tissues.