Cold tolerance of invasive freshwater snails,Pomacea canaliculata,P. maculata,and their hybrids helps explain their different distributions

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Synthetic studies on oligosaccharides composed of 5-thioglucopyranose units

Glycosylation reactions of 5-thioglucopyranosyl trichloroacetimidates bearing ethereal protective groups at the 2-O-position 14-15, and 37 proceed smoothly to give alpha-glycosides stereoselectively by using a catalytic amount of silyl triflate. This methodology allowed us to achieve syntheses of sulfur-substituted isomaltotetraoside 2 and maltotetraoside 3. These studies also revealed that benzoyl-protected 5-thioglucopyranosyl trichloroacetimidate 12 underwent beta-selective glycosylation with C6-OH glucopyranosyl acceptors upon activation by BF3OEt2. This was applied for preparation of sulfur-substituted gentiobiosides 1 and 46.     

Factors contributing to cerebral hypomyelination in the growth hormone-deficientlittle mouse

We attempted to delineate the events leading to hypomyelination in the brain of thelittle mouse, a promising murine model of isolated growth hormone deficiency. At 20 days of age, the mutant mouse brain weighed less than its normal counterpart, and this difference in brain weight persisted. Increase in CNPase activity was found to be suppressed in the cerebrum throughout the developmental stage, but not in the other parts of the brain. Differences in cerebral DNA content between thelittle and normal mice first became apparent on the 10th day of age. Thereafter, the rate of increase in thelittle brain consistently lagged behind the normal. [³H]Thymidine incorporation into the DNA fraction in vivo on the 7th day of age, when glial cell proliferation in the normal cerebrum is most active, was approximately half that of the controls in all parts of thelittle brain. These findings indicate that the hypomyelination of the mutant cerebrum might result from reduced oligodendroglial proliferation due to growth hormone deficiency.     

A case of acute gastric mucosal lesions associated with Helicobacter heilmannii infection

A 69-year-old-woman presented with acute epigastric pain, nausea, vomiting and heartburn. Endoscopy disclosed acute gastric mucosal lesions including mucosal edema, erosions, and ulcers with blood crusts in the antrum. Touch cytology and histological assessment obtained from the affected mucosa revealed acute neutrophilic gastritis and single longer and more coiled organisms than Helicobacter pylori, suggesting Helicobacter heilmannii. Electron micropragh confirmed the characteristic morphology. Despite a positive rapid urease test, H. pylori was not isolated by culture or detected by histology and Gram smears. Based on these findings, a diagnosis of acute gastric mucosal lesions associated with H. heilmannii infection was established. This was successfully treated with a 2-week triple therapy consisting of lansoprazole, clarithromycin and metronidazole with persistent endoscopic and histological remission. This is a rare case of H. heilmannii-associated acute gastric mucosal lesions, diagnosed by morphology using touch cytology and histology. The patient might benefit from antimicrobial treatment employing the regimen effective for H. pylori.     

Sensitivity of the surface coat of the halotolerant green alga Dunaliella parva (Volvocales, Chlorophyceae) to lysozyme

The surface coat of Dunaliella parva Lerche was investigated using several techniques. Degradation by several cell lytic enzymes and ultrastructural observation revealed that D. parva has a specialized cell surface structure containing a glycoprotein that is sensitive not only to proteinases but also to lysozyme. This sensitivity was also demonstrated by electrophoresis of the cells and measurement of released glycerol after enzyme treatment. Immunochemical labeling indicated that the surface glycoprotein of D. parva is analogous to pepti-doglycan.     

Characterization and imprinting status of OBPH1/Obph1 gene: implications for an extended imprinting domain in human and mouse

Human 11p15.5, as well as its orthologous mouse 7F4/F5, is known as the imprinting domain extending from IPL/Ipl to H19. OBPH1 and Obph1 are located beyond the presumed imprinting boundary on the IPL/Ipl side. We determined full-length cDNAs and complete genomic structures of both orthologues. We also investigated their precise imprinting and methylation status. The orthologues resembled each other in genomic structure and in the position of the 5' CpG island and were expressed ubiquitously. OBPH1 and Obph1 were predominantly expressed from the maternal allele only in placenta, with hypo- and not differentially methylated 5' CpG islands in both species. These results suggested that the imprinting domain would extend beyond the presumed imprinting boundary and that methylation of the 5' CpG island was not associated with the imprinting status in either species. It remains to be elucidated whether the gene is under the control of the KIP2/LIT1 subdomain or is regulated by a specific mechanism. Analysis of the precise genomic sequence around the region should help resolve this question.     

Distinct Distribution of Deoxynivalenol,Nivalenol, and Ergosterol in <Emphasis Type="Italic">Fusarium</Emphasis>-infected Japanese Soft Red Winter Wheat Milling Fractions

The occurrence of mycotoxins in small grain cereals and their retention in final products are serious concerns for food safety. Previously, we investigated the fate of deoxynivalenol and nivalenol in a Japanese soft red winter wheat cultivar during milling and we found that deoxynivalenol and/or nivalenol was readily distributed among flours for human consumption. In the present study, we analyzed the ergosterol concentrations in the milling fractions as an index of fungal biomass to elucidate the relationship between deoxynivalenol/nivalenol accumulation and fungal invasion into the grain, after the in-house validation of an analytical method for quantifying ergosterol in the resulting milling fractions (patent flour, low-grade flour, bran, and shorts). Using three samples with different levels of deoxynivalenol and/or nivalenol contamination, the contents of deoxynivalenol/nivalenol and ergosterol in the resulting milling fractions were evaluated. The concentration of ergosterol was always lowest in patent flour and highest in bran or shorts, indicating that most of the fungi is retained in the outer layers of grain (bran and shorts) even in highly contaminated grain. On the other hand, the concentrations of deoxynivalenol and nivalenol were similar in the low-grade and patent flours and only slightly lower than in the medium-level and high-level contaminated grains. Moreover, the percentage distribution of ergosterol was higher in bran than in other fractions in all cases, which differed from that of deoxynivalenol/nivalenol. This result indicates the diffusion of deoxynivalenol/nivalenol inside the grain that is independent of fungal invasion.     

A review of studies and measures to improve the mycotoxicological safety of traditional Japanese mold-fermented foods

Miso (fermented soybean paste), shoyu (soy sauce) and sake (rice wine) are traditional moldfermented foods in Japan and have been consumed throughout much of its history. These have long been considered safe foods. In this contribution we review and summarize long-term studies to investigate potential problems with mycotoxin contamination of these products. The fungal cultures used for fermentation of these products are called “koji-molds” and mainly consist of strains ofAspergillus oryzae. A. oryzae belongs to theA. flavus group taxonomically, which is generally known to be a main producer of aflatoxins. Therefore, we studied the productivity of aflatoxins by various koji-molds, as well as the possibility of aflatoxin contamination of rice (which is used in the production of fermented foods), miso, shoyu and sake. Rice was found to be free from aflatoxins. Furthermore, none of the tested koji-molds produced any detectable levels of aflatoxins, consequently no aflatoxins were found in miso, shoyu, or sake. However, some koji-molds are known to produce cyclopiazonic acid (CPA) and kojic acid (KA). We studied the production of CPA and KA by various commercial koji-molds and identified some strains that produce relatively high amounts of CPA or KA. Consequently, we advised food industry not to use these strains. Although mycotoxin contamination of these products is therefore presently very low, further attempts should be made to completely eliminate CPA and KA from fermented foods.