The original papers appeared in the Journal of Japanese Forestry Society vol. 86, no. 3 in Japanese with English abstracts

Abstracts from the Journal of Japanese Forestry Society

The original papers appeared in the Journal of Japanese Forestry Society vol. 86, no. 3 in Japanese with English abstracts     

alpha-Glucosidase inhibitory profile of catechins and theaflavins

To clarify the postprandial glucose suppression effect of flavonoids, the inhibitory effects of catechins and theaflavins against alpha-glucosidase (AGH) were examined in this study. It was initially demonstrated that theaflavins and catechins preferentially inhibited maltase rather than sucrase in an immobilized AGH inhibitory assay system. For the maltase inhibitory effects of theaflavins, the effects were observed in descending order of potency of theaflavin (TF)-3-O-gallate (Gal) > TF-3,3'-di-O-Gal > TF-3'-O-Gal > TF. This suggests that the AGH inhibition induced by theaflavins is closely associated with the presence of a free hydroxyl group at the 3'-position of TF as well as the esterification of TF with a mono-Gal group. In addition, the R-configuration at the 3'-position of TF-3-O-Gal showed a higher inhibitory activity than the S-configuration. As a result of a single oral administration of maltose (2 g/kg) in rats, a significant reduction in blood glucose level was observed at a dose of 10 mg/kg of TF-3-O-Gal, demonstrating for the first time that TF-3-O-Gal can suppress glucose production from maltose through inhibition of AGH in the gut.     

Pericardial mesothelioma in a neonatal calf

We encountered an extremely rare tumor, a pericardial mesothelioma, in a neonatal calf. The patient calf showed severe abdominal distention, and died immediately after birth. The thoracic cavity was contained a huge heart with a large amount of pericardial fluid. A number of granular and cobblestone-like nodules were dispersed over the epicardium and pericardium. The nodules consisted of papillary proliferations of neoplastic cells, and the neoplasm occasionally showed mesenchymal proliferations. Immunohistochemistry revealed that they had the characteristics of mesothelial cells (cytokeratin-and vimentin-positive), and the neoplasm was diagnosed as mesothelioma.     

Phyto- and endogenous estrogens differently activate intracellular calcium ion mobilization in bovine endometrial cells

The main purpose of this study was to check whether phyto- and endogenous estrogens influence calcium ion mobilization [Ca(2+)](i) in bovine endometrial cells and whether this action is connected with biological effects i.e. prostaglandin (PG)F(2alpha) production. In our study we used two calcium measurement methods by comparing the microscopic method with widely used quantitative - spectrofluorometric method of [Ca(2+)](i) measurement. We also wanted to confirm whether visualization of calcium ion [Ca(2+)](i) in cells using microscopic method supported by micro image analysis (Micro Image Olympus system) reflects real, qualitative changes in the ion concentration. In both methods a cell-permeable form of fluorescent [Ca(2+)](i) indicator Fura-2 was used. Cultured bovine endometrial epithelial and stromal cells influenced by phorbol-2-myristate-13-acetate (PMA; positive control), estradiol 17-beta (E(2); endogenous estrogen) and active metabolites of phytoestrogens (environmental estrogens) were used as a model to study PGF(2alpha) secretion and [Ca(2+)](i) mobilization in the cells. Equol and para-ethyl-phenol in doses of 10(-8)-10(-6) M increased PGF(2alpha) concentration both in epithelial and stromal cells (P<0.05). In both methods, equol and para-ethyl-phenol did not cause intracellular [Ca(2+)](i) mobilization in epithelial and stromal cells (P>0.05). Both methods revealed that only E(2) and PMA induced intracellular [Ca(2+)](i) mobilization in epithelial and stromal cells (P<0.05). The results of both methods were highly correlated (P<0.001; r=0.82 for epithelial cells and r=0.89 for stromal cells). In conclusion, both methods gave approximately the same results and showed that phytoestrogens, in contrast to PMA and E(2), did not cause intracellular [Ca(2+)](i) mobilization in endometrial cells. The obtained results proved that the [Ca(2+)](i) visualization method supported by micro image analysis can produce similar results to the spectrofluorometric method.     

Patterns of shoot mortality in Betula platyphylla in northern Japan

To understand the development of crown structure in Betula platyphylla Sukatch., mortality patterns of long shoots were analyzed quantitatively. We selected 25 saplings growing under various light conditions and measured the relative photosynthetically active radiation (rPAR) at, and the three-dimensional position of, first-order branches. A long shoot was assigned "no buds" (NB) status if it lacked buds at the end of the growing season, including at the tips of short shoots. A long shoot was classified as dead if it was NB and all the offspring long shoots issuing from it were NB. The probability that a leafy long shoot (a current-year long shoot with leaves or an older long shoot with short shoots with leaves) would become NB by the end of the season was positively dependent on shoot age and branch age, and negatively dependent on shoot length, centripetal shoot order, branch height and rPAR at the branch. Randomization tests revealed that shoots became NB and dead in clusters of connected shoots. In particular, shoot clusters originating from 3-year-old shoots were more likely to die than expected if each shoot was assumed to become NB regardless of the connection. Stepwise logistic regression revealed that the maximum rPAR within the crown of an individual tree had a significant effect on the mortality rate of 3-year-old shoot clusters, together with the rPAR at the level of the branch and other structural entities. Correlative inhibition is an important mechanism for determining shoot mortality patterns.     

Spironolactone, but not Eplerenone, Impairs Glucose Tolerance in a Rat Model of Metabolic Syndrome

Although some clinical studies have suggested that spironolactone (SPL), a mineralocorticoid receptor (MR) antagonist, appears to increase the blood glucose levels, experimental studies have not supported this notion. Here, we investigated the effect of SPL on blood glucose levels in SHR/NDmcr-cp(cp/cp) (ND) rats, an animal model of metabolic syndrome, in comparison with that of eplerenone (EPL), another MR antagonist. At the same dose of 100 mg/kg, SPL and EPL increased the urinary sodium-to-potassium ratio to a comparable extent, indicating that both agents have similar renal MR antagonistic efficacy in ND rats. Interestingly, SPL but not EPL significantly increased the level of blood glucose. The oral glucose tolerance test revealed that treatment with SPL led to glucose intolerance. The levels of serum insulin and adiponectin, regulators of the blood glucose level, were virtually unaffected by treatment with SPL. On the other hand, SPL induced a marked increase in the blood level of aldosterone, known to be a risk factor for insulin resistance. These results demonstrate that in comparison with EPL, SPL characteristically impairs glucose tolerance in an animal model of metabolic syndrome, in association with a higher blood level of aldosterone.     

Evaluation of myelotoxicity in dietary restricted rats

The purpose of this study was to clarify the effect of decreased food consumption on evaluation of myelotoxicity in routine general toxicity studies. Male rats were divided into the following 7 groups: 12, 15, and 18 mg/kg 5-fluorouracil (5-FU) treatment groups (FU12, FU15 and FU18); dietary restriction groups (R12, R15 and R18 receiving the same amount of food as the rats in the FU12, FU15 and FU18 groups, respectively); and a nontreated control group (NT). We compared the changes in body weight, hematology and the results of cytological analyses of bone marrow and histopathology among the groups after administration and recovery periods of 14 and 7 days, respectively. At the end of the administration period, the FU15 and FU18 groups showed decreases in many hematologic and bone marrow parameters that were all similar to those in the corresponding dietary restriction groups (R15 and R18). A granulocyte abnormality (polyploidy: frequency of 1% or less) was also observed in all 5-FU treated groups. At the end of the recovery period, increases in the reticulocyte and platelet counts and extramedullary hematopoiesis of the spleen were observed in the 5-FU treated groups. These results indicate that the results of general toxicity studies in rats should be evaluated in consideration of dietary restriction effects when food consumption is decreased at about 30-40% or more. Careful morphological observation of hemocytes would be helpful in distinguishing the effect of a drug from that of dietary restriction in relation to hematological and bone marrow parameters. Performance of a recovery test to determine the reactive response of hematopoiesis is also recommended.     

Chemistry of Sediment Pore Water in Aquaculture Ponds Built on Clayey Ultisols at Auburn, Alabama

The composition of sediment pore water was determined for ponds constructed on clayey Ultisols at Auburn, Alabama. Pore water was anaerobic and contained much higher concentrations of ferrous iron (Fe²⁺), soluble reactive phosphorus (SRP), total phosphorus (TP), total ammonia-nitrogen (TAN), and sulfide (S²⁻) than surface or bottom waters. Concentrations of SRP and TP in pore water were higher in ponds with high soil phosphorus concentrations than in a new pond with less soil phosphorus. Increased concentrations of organic matter in soil or larger inputs of feed to ponds favored greater microbial activity in soils and higher concentrations of TAN in pore water. The pH of pore water was 6.5–7.0, and pH was apparently controlled by the equilibrium:

Movement of Fe²⁺, SRP, and S²⁻ from pore water into pond water apparently was prevented by the oxidized layer of soil just below the soil-water interface. Pond managers should concentrate on maintaining this oxidized layer to reduce the tendency for toxic substances to diffuse into the pond water.     

Correction to: Precocious maturation in male tiger pufferfish Takifugu rubripes: genetics and endocrinology

Fisheries Science - A correction to this paper has been published: https://doi.org/10.1007/s12562-021-01505-w     

Purification and characterization of cathepsin S from hepatopancreas of carp Cyprinus carpio

SUMMARY: Cathepsin S was purified from carp hepatopancreas to homogeneity up to 300-fold. The amino acid sequence of its NH₂-terminus was determined to be V-P-D-A-M-D-W-Y-N-K-G-Y-V-T-D-V-K-N-Q. On the contrary, that of purified cathepsin L from carp hepatopancreas was to be V-P-N-S-L-D-W-R-E-K-G. Purified cathepsin S consisted of a single chain with 37 kDa estimated by sodium dodecylsulfate–polyacrylamide gel electrophoresis. The enzyme had strong hydrolytic activity toward Z-Phe-Arg-MCA with the pH optimum of 7.0, but this lacked the ability to hydrolyze most of the other MCA substrates. The optimum pH of cathepsin S for protein substrate (carp myosin heavy chain) was also to be pH 7.0. These properties of purified cathepsin S obviously differ from cathepsins B and L. The enzyme activity was totally inhibited by E-64, leupeptin, 5–5'-dithiobis (2-nitro-benzoic acid) and p -tosyl-lys chloromethylketone as well.