An outbreak of bovine ephemeral fever in Nagasaki Prefecture in 1988

In October, 1988, bovine ephemeral fever (BEF) occurred in Nagasaki Prefecture and throughout Kyushu island, with the exception Miyazaki Prefecture. The first outbreak occurred in Hirado-shi on October 17. The total number of diseased cattle was 24 in 24 farms in Nagasaki Prefecture. The clinical findings were mainly sudden fever, anorexia, and instability in standing. The serum neutralizing antibodies against BEF virus (BEFV) rose in all infected cattle. Twelve strains of the virus were isolated in HmLu-1 cell cultures made directly from the heparinized blood of 17 infected cattle. The buffy coat was mainly collected from the samples and washed three times with phosphate buffered saline. These isolates were all neutralized by an antiserum against BEFV (Yamaguchi strain). With the aid of an electron microscope, a representative of isolates named Hirado-9 with a length of 150 nm was seen in the sample of infected HmLu-1 cell cultures. Both Hirado-9 and Yamaguchi strains reacted with antisera. The outbreak of BEF in 1988 was the first since 1971 in Nagasaki Prefecture. The result proved that BEFV can be easily isolated in HmLu-1 cell culture from the washed blood cells of infected cattle.     

Naturally occurring antifungal agents against Zygosaccharomyces bailii and their synergism

Polygodial was found to exhibit a fungicidal activity against a food spoilage yeast, Zygosaccharomyces bailii, with the minimum fungicidal concentration (MFC) of 50 microg/mL (0.17 mM). The time-kill curve study showed that polygodial was fungicidal at any growth stage. The primary action of polygodial comes from its ability to disrupt the native membrane-associated function of integral proteins as nonionic surface active agents (surfactants) followed by a decrease in plasma membrane fluidity. The fungicidal activity of polygodial was increased 128-fold in combination with a sublethal amount (equivalent of 1/2 MFC) of anethole and vice versa relative to the fungicidal activity of anethole. The fungicidal activity of sorbic acid was enhanced 512-fold in combination with 1/2 MFC of polygodial. Conversely, the fungicidal activity of polygodial was enhanced 128-fold in combination with 1/2 MFC of sorbic acid.     

Naturally occurring anti-Salmonella agents.

Polygodial and (2E)-hexenal were found to possess antibacterial activity against Salmonella choleraesuis with the minimum bactericidal concentrations (MBC) of 50 microg/mL (0.17 mM) and 100 microg/mL (0.98 mM), respectively. The time kill curve study showed that these two alpha,beta-unsaturated aldehydes were bactericidal against this food-borne bacterium at any stage of growth. However, they showed different effects on the growth of S. choleraesuis. The combination of polygodial and anethole exhibited strong synergism on their bacteriostatic action but only marginal synergism on their bactericidal action.     

Antitumor activity of compounds isolated from leaves of Eriobotrya japonica

In a search for possible antitumor agents from natural sources, megastigmane glycosides and polyphenolic constituents isolated from the leaves of Eriobotrya japonica (Rosaceae) were found to inhibit the 12-O-tetradecanoylphorbol-13-acetate (TPA)-induced activation of Epstein-Barr virus early antigen in Raji cells. Roseoside and procyanidin B-2 were among the active compounds found in an in vitro assay; these compounds were further assessed for antitumor activity in vivo in a two-stage carcinogenesis assay on mouse skin. Roseoside significantly delayed carcinogenesis induced by peroxynitrite (initiator) and TPA (promoter), and its potency was comparable to that of a green tea polyphenol, (-)-epigallocatechin 3-O-gallate, in the same assay.     

Antibacterial activity of akyl gallates against Bacillus subtilis

The antibacterial activity of a series of alkyl gallates (3,4,5-trihydroxybenzoates) against Gram-positive bacteria was tested using a broth dilution method. All of the Gram-positive bacteria tested were susceptible to alkyl gallates, and this activity was found to correlate with the alkyl chain length. The antibacterial activity of alkyl gallates against Bacillus subtilis was a parabolic function of their lipophilicity and maximized with alkyl chain length between C(8) and C(11). Notably, alkyl gallates were found to be bactericidal against B. subtilis ATCC 9372, but this activity was significantly affected by the endospore formation in the culture. The antibacterial activity of alkyl gallates likely comes at least in part from their ability to inhibit the membrane respiratory chain but is not due to the prooxidant action.     

Altitudinal differences in bark stripping by sika deer in the subalpine coniferous forest of Mt. Fuji

Deer expansion is a growing concern for forest ecosystem management. In Japan, upward expansion to subalpine and alpine areas has reached alarming proportions in recent years. We examined bark stripping by sika deer along an altitudinal gradient in the subalpine coniferous forest at three altitude ranges (1800-2000 m, 2000-2200 m, and 2200-2400 m) on the southern slope of Mt. Fuji. We tested differences in densities and diameter at breast height (DBH) of trees and those with bark-stripped stems of all tree species among the three altitude ranges. Then, we compared the relative densities of deer, based on pellet counts, to determine the impact of deer in relation to deer use and forest stand patterns across the altitudinal range studied. The results of the study show that differences in bark stripping by sika deer depended largely on the elevation and the species. Larger stems were sparsely distributed in the lowest elevation zone between 1800 and 2000 m. The relative density of deer was highest in the areas exhibiting high bark-stripping intensity on small regenerating trees of the dominant coniferous species, Abies veitchii, and on broadleaf species. In the highest elevation zone between 2200 and 2400 m, smaller stems were densely distributed, and the relative deer density was lowest where the bark-stripping intensity on small stems was lower for all three species studied. The damage to subalpine tree stems corresponded to the availability of palatable tree species with a small diameter, as reflected by the successional stage along the elevational gradient of subalpine forest on Mt. Fuji. These results suggest that the continuous impact of bark stripping on the dominant tree species might cause severe changes in forest succession.     

Antifungal mechanism of polygodial

The primary antifungal action of polygodial comes in part from its ability to function as a nonionic surfactant, disrupting the lipid-protein interface of integral proteins and denaturing their conformation. As a result, the antifungal mechanism of this sesquiterpene dialdehyde is associated with the membrane functions or derangement of the membrane. For example, the glucose-induced medium acidification process of Saccharomyces cerevisiae was inhibited by polygodial, presumably caused by inhibition of the plasma membrane H(+)-ATPase. However, the potent antifungal activity of polygodial results from its multiple functions.     

Lipoxygenase inhibitory activity of anacardic acids

6[8'(Z)-pentadecenyl]salicylic acid, otherwise known as anacardic acid (C15:1), inhibited the linoleic acid peroxidation catalyzed by soybean lipoxygenase-1 (EC 1.13.11.12, type 1) with an IC50 of 6.8 microM. The inhibition of the enzyme by anacardic acid (C15:1) is a slow and reversible reaction without residual activity. The inhibition kinetics analyzed by Dixon plots indicates that anacardic acid (C15:1) is a competitive inhibitor and the inhibition constant, KI, was obtained as 2.8 microM. Although anacardic acid (C15:1) inhibited the linoleic acid peroxidation without being oxidized, 6[8'(Z),11'(Z)-pentadecadienyl]salicylic acid, otherwise known as anacardic acid (C15:2), was dioxygenated at low concentrations as a substrate. In addition, anacardic acid (C15:2) was also found to exhibit time-dependent inhibition of lipoxygenase-1. The alk(en)yl side chain of anacardic acids is essential to elicit the inhibitory activity. However, the hydrophobic interaction alone is not enough because cardanol (C15:1), which possesses the same side chain as anacardic acid (C15:1), acted neither as a substrate nor as an inhibitor.     

Pachyelasides A-D, novel molluscicidal triterpene saponins from Pachyelasma tessmannii

This is the first report for secondary metabolites in an African medicinal plant, Pachyelasma tessmannii (Leguminosae). Four novel saponins, pachyelasides A-D, were isolated from the methanol extract of the root bark by using recycling HPLC. These compounds showed molluscicidal activity (LD(50) < or =8.0 mug/mL) against the South American snail, Biomphalaria glabratus. The structures were determined on the basis of extensive nuclear magnetic resonance spectroscopic and matrix-assisted laser desorption/ionization time-of-flight mass spectrometric studies.