Involvement of steroid hormones in the preovulatory gonadotropin surge in female goldfish

Goldfish,Carassius auratus, spawn several times within a spawning season. A gonadotropin (GtH) surge occurs at the time of ovulation in this cyprinid species. This ovulatory GtH surge mediates the processes of final oocyte maturation and ovulation, and occurs at the end of each spawning cycle. Within a cycle, there is a shift in the predominant plasma steroid from estradiol to testosterone, and finally 17α, 20β-dihydroxy-4-pregnen-3-one at the time of the ovulatory GtH surge. High levels of testosterone were always observed before ovulation. When ovariectomized or sexually regressed female goldfish were implanted with testosterone, they exhibited a GtH surge which was similar to those normally observed at ovulation. These results strongly suggest that elevated plasma testosterone is an important physiological requirement for the occurrence of the GtH surge.     

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.     

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.     

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.     

High-density electron anions in a nanoporous single crystal: [Ca24Al28O64]4+(4e-)

We removed approximately 100% of clathrated oxygen ions from the crystallographic cages in a single crystal of 12CaO.7Al2O3, leading to the formation of high-density (approximately 2 x 10(21) cm-3) electrons highly localized in the cages. The resulting electron forms a structure that we interpret as an F+ center and migrates throughout the crystal by hopping to a neighboring cage with conductivity approximately 100 siemens per centimeter, demonstrating that the encaged electron behaves as an anion. The electron anions couple antiferromagnetically with each other, forming a diamagnetic pair or singlet bipolaron. The resulting [Ca24Al28O64]4+(4e-) may be regarded as a thermally and chemically stable single crystalline "electride."     

芽孢杆菌WY45产β-甘露聚糖酶发酵条件的优化

为获得最佳产酶配方，同时获得高活力的β-甘露聚糖酶，经碳源、氮源、碳氮质量比、初始pH和培养温度5个单因素发酵条件的优化，得到芽孢杆菌WY45发酵产β-甘露聚糖酶的最适发酵培养条件：以4g／L魔芋精粉为碳源，1．33g／L大豆蛋白胨为氮源，碳氮质量比为4／1，初始pH5．5，50℃培养时间96h。此条件下，β-甘露聚糖酶活性最高可达2800U／mL。     

Quantitative nested real-time PCR detection of <Emphasis Type="Italic">Verticillium longisporum</Emphasis> and <Emphasis Type="Italic">V. dahliae</Emphasis> in the soil of cabbage fields

Verticillium longisporum and V. dahliae, causal agents of Verticillium wilt, are spreading through the cabbage fields of Gunma Prefecture. Using the V. longisporum-specific intron within the 18S rDNA and differences between ITS 5.8S rDNA sequences in Japanese isolates of V. longisporum and V. dahliae, we developed three quantitative nested real-time (QNRT) PCR assays. The QNRT-PCR quantification of V. longisporum or V. dahliae in cabbage field soil was consistent with the severity of Verticillium wilt disease in those fields. In field trials of resistant cultivar YR Ranpo grown for three seasons in soil infested with the pathogen, disease severity and pathogen density in the soil were significantly reduced in a field moderately contaminated by V. dahliae, but only slightly reduced in a highly contaminated field. These results suggest that continuous cultivation of a resistant cultivar is an effective way to reduce the pathogen population. QNRT-PCR assays provide a powerful analytical tool to evaluate the soil population dynamics of V. longisporum and V. dahliae for disease management.     

Lipoxygenase inhibitory activity of octyl gallate

Octyl gallate inhibited soybean lipoxygenase-1 (EC 1.13.11.12, type I) with an IC(50) of 1.3 microM. The inhibition of the enzyme by octyl gallate is a slow and reversible reaction without residual activity. The inhibition kinetics analyzed by Lineweaver-Burk plots indicates that octyl gallate is a competitive inhibitor, and the inhibition constant, K(I), was obtained as 0.54 microM. One molecule of octyl gallate scavenged six molecules of 1,1-diphenyl-2-picrylhydrazyl and inhibited autoxidative lipid peroxidation. In addition, octyl gallate was effective in preventing lipid peroxidation.     

Ingestion of water-soluble soybean fiber prevents osteopenia and hypercholesterolemia induced by ovariectomy in rats

This study examined the effects of feeding water-soluble soybean fiber (WSSF), a highly fermentable dietary fiber with low viscosity, on intestinal calcium (Ca) absorption, bone mineral content, and serum total cholesterol levels using female Sprague-Dawley rats (5 weeks old) with or without ovariectomy (OVX). The rats in each group were fed a WSSF (50 g/kg of diet) or WSSF-free diet for 4 weeks. Ca absorption was higher in OVX rats fed the WSSF diet than in OVX rats fed the WSSF-free diet. Femoral Ca content in both sham and OVX rats fed the WSSF diet was higher than that in rats fed the WSSF-free diet. The serum total cholesterol levels were elevated after OVX compared with that in the sham rats, and this elevation was prevented by the WSSF diet. In conclusion, ingestion of WSSF prevented osteopenia and hypercholesterolemia induced by ovariectomy in rats.