Aflatoxin and cyclopiazonic acid production by a sclerotium-producing Aspergillus tamarii strain.

The production of aflatoxins B1 and B2 by Aspergillus tamarii (subgenus Circumdati section Flavi) is reported for the first time. The fungus was isolated from soil collected from a tea (Camellia sinensis) field in Miyazaki Prefecture, Japan. Three single-spore cultures, NRRL 25517, NRRL 25518, and NRRL 25519, were derived from subcultures of the original isolate 19 (MZ2). Each of these single-spore cultures of A. tamarii produced aflatoxins B1 and B2 and cyclopiazonic acid, as well as black, pear-shaped sclerotia. The demonstration of aflatoxin production by A. tamarii is examined in connection with A. tamarii phylogenetic relationships, chemical ecology, and potential use in food fermentations.     

The molecular analysis ofbrown eye color mutations isolated from geographically discrete populations ofDrosophila melanogaster

A large proportion of spontaneous mutations inDrosophila melanogaster strains of laboratory origin are associated with insertions of mobile DNA elements. As a first step toward determining whether spontaneous laboratory mutations are predictive for mutational events occurring in the wild, recessivebrown (bw) eye color mutants were isolated. By inbreeding the progeny of wild-caughtDrosophila melanogaster females,bw mutations were isolated from seven separate geographic sites distributed among Japan, California, Siberia and Hungary. Among a total of 14 mutations studied, no case of transposon mutagenesis was found. At least 4 mutations are associated with small deletions in thebw gene. The remainder are inseparable from wild-typebw by Southern analysis and are presumed to be basepair changes or very small indels. Although only two spontaneousbw mutants of laboratory origin have been analyzed molecularly, one is a mobile element insertion.     

Simultaneous determination of citalopram and its metabolites by high-performance liquid chromatography with column switching and fluorescence detection by direct plasma injection

High-performance liquid chromatography with a successive column-switching technique was developed for simultaneous determination of citalopram and its four metabolites in plasma. Plasma samples were injected directly, and the target compounds were purified and concentrated with an inexpensive commercial octadecyl guard column. Then, the six-port valve was switched, and the compounds retained in the column were eluted by the back-flush method using 20 mM phosphate buffer (pH 4.6)-acetonitrile (70:30, v/v) containing 0.1% diethylamine and separated with an ODS column. The compounds were assayed with a fluorescence detector at an excitation wavelength of 249 nm and an emission wavelength of 302 nm. At least 30 plasma samples could be treated with an octadecyl guard column. The limits of quantitation of this method were 2.0 ng/ml for citalopram, desmethylcitalopram, didesmethylcitalopram, citalopram propionic acid and citalopram N-oxide. This method was applied to a pharmacokinetic study in dogs and a toxicokinetic study in rats.     

Interannual fluctuations in recruitment and growth of the sardine,Sardinops melanostictus,in the sea of Japan and adjacent waters

Recruitment and growth of the sardineSardinops melanostictus fluctuated markedly in the Sea of Japan and adjacent waters between 1978 and 1993. Stock size was calculated using Virtual Population Analysis and average body length in each age class was determined by the number of annual rings on the scales. There is an inverse correlation between average water temperature at a depth of 50 m in the coastal area of the mainland of Japan in winter (January to March) and recruitmentR defined as the number of individuals at 1 year old. There is also an inverse correlation between spawning stock sizeE and reproductive success in (R/E). A multiple regression model using spawning stock size and water temperature in winter as independent variables can explain 73% of variance in reproductive success. It suggests that both density-dependent and density-independent factors perform important roles determining reproductive success. There is an inverse correlation between body length and stock size and this suggests that there is a density-dependent effect on the growth of the sardine.     

In vitro viability and ultrastructural changes in bovine oocytes treated with a vitrification solution

Abattoir-derived oocytes were exposed to a concentrated cryoprotectant solution (DAP213: 2 M DMSO, 1 M acetamide, 3 M propanediol, and 10% FCS in TCM199) for 1.5 or 5 min at the germinal vesicle (GV) stage or after maturation in vitro (IVM). Their viability was assessed by in vitro fertilization (IVF) and culture (IVC) to blastocysts. To investigate the effect of DAP213 on the ultrastructure, GV and IVM oocytes were processed for transmission electron microscopy (TEM) before (control) or after exposure to the cryoprotectant. DAP213 induced profound ultrastructural modifications to the microvilli and mitochondria, resulted in large vesicle formation, and, most significantly, caused the premature release of the cortical granules (CG). In IVM oocytes exposed to the cryoproteclant for 5 min, exocytosis of CG into the perivitelline space was common and the IVF rate was reduced (P <.05). After exposure for 5 min, GV oocytes displayed clusters of CG comparable to controls, but after IVM-IVF, polyspermy rate was increased (P <.05). Furthermore, treated GV oocytes showed a reduced rate of cleavage and blastocyst formation and an increased percentage of oocytes exhibiting alterations in organelles, whereas the viability and ultrastructure of IVM oocytes treated for 1.5 min was not different from controls. These observations demonstrate that (1) cortical granule kinetics is one of the key elements controlling fertilizability of bovine oocytes treated with cryoprotectant, and (2) GV oocytes are more sensitive to the cryoprotectant than those that have already been matured in vitro.     

Isolation and identification of (2S)-2-amino-5-chloro-4-hydroxy-5-hexenoic acid from anAmanita of the sectionRoanokenses (Amanitaceae)

A chlorine-containing non-protein amino acid which was recently discovered from the fruit bodies ofAmanita gymnopus (2S)-2-amino-5-chloro-4-hydroxy-5-hexenoic acid, was isolated and crystallized for the first time from the fruit bodies of an unknown member ofAmanita belonging to the sectionRoanokenses, subsectionSolitariae. The results of elementary analyses, determination of optical rotations,¹H- and¹³C-NMR-spectra, and some chemical reactions supported an earlier proposed structure.Part 24 in the series Biochemical studies of nitrogen compounds in fungi. for Part 23, see Hatanaka, S. I. et al. 1994. this journal35: 391–394.     

Effects of visible light and other environmental factors on the production of oxygen radicals by hamster embryos

Previous studies have demonstrated that developing hamster embryos are very sensitive to visible light. In order to elucidate why visible light exerts a toxic effect on hamster embryos, we examined the effect of visible light on the production of hydrogen peroxide (H(2)O(2)) within individual embryos, using a fluorimetric method. In addition, we examined the H(2)O(2) generating capacity of other factors which are known to be related to the in vitro developmental capacity of hamster embryos. One-cell hamster embryos were cultured with 2',7'-dichlorodihydrofluorescin diacetate, and the fluorescence emissions of the H(2)O(2)-dependent oxidative product in the embryos were measured using an Olympus microscopic photometry system. When embryos were exposed to visible light (14,000 lux) for a specified period (0, 0.5, 1, 2 or 3 min) prior to measurement, the fluorescence emissions from embryos increased with the time of exposure to visible light. An exposure of even 0.5 min resulted in a significant increase in hydrogen peroxide. This increase was more rapid in embryos cultured under 20% O(2) than in those cultured under 5% O(2), and the response was quicker than that observed in mouse embryos. The fluorescence emissions from embryos cultured under 5% O(2) were significantly (P<0.001) lower than those from embryos cultured under 20% O(2) in TLP medium. However, the effects of different oxygen tensions on fluorescence emissions were medium-dependent, and were not significant in embryos cultured in HECM-1 medium. The addition of L-cysteine to or elimination of phenol red from the media decreased the fluorescence emissions from embryos (P<0.001), but glucose and phosphate did not affect them. These results suggest that the toxic effect of visible light on the in vitro development of hamster embryos might be due to increased generation of reactive oxygen species, induced by the visible light. This could be one of the explanations for the strict conditions required for overcoming the in vitro developmental block. It is also suggested that the promotive effects of low oxygen culture and L-cysteine on embryo development seem to be derived from their ability to reduce reactive oxygen species.     

Isolation of an Internal Deletion Mutant of the Arabidopsis thaliana ABI3 Gene

An Arabidopsis thaliana mutant that produces green seeds thatare highly insensitive to exogenous ABA, non-dormant and severelydesiccation intolerant was isolated from a population of fastneutron-irradiated seeds. Molecular and genetic analysis ofthis mutant shows that these phenotypes are caused by an internaldeletion of approximately one third of the ABI3 gene. Thereforeabi3 mutants with the above phenotypes are representative ofnull alleles at this locus. (Received December 3, 1993; Accepted January 22, 1994)