To investigate whether female fertility decreases with age due to poor oocyte quality, we examined the presence of DNA fragmentation in ovulated oocytes from young, mature and aged mice. Oocytes from three age groups of female mice (7-8, 20-24 and 40-48 weeks) were retrieved from the oviducts 15 h after human chorionic gonadotrophin (HCG) injection. Oocytes from each mouse were incubated in a CO2 incubator for 0-60 h in human tubal fluid (HTF). After incubation, each oocyte was stained with the terminal deoxynucleotidyl transferase-mediated dUDP nick-end labelling (TUNEL) method. The rate of DNA fragmentation (interpreted as apoptotic changes) was significantly higher for oocytes from aged mice, and the fertilization rate was significantly lower, compared with oocytes from young and mature mice. Our results suggest that DNA fragmentation of oocytes might be one of the reasons for poor oocyte quality and lower fertility in the aged group.

S U M M A R YCell death is roughly categorized as either apoptosis or necrosis. For better understanding of the differences in DNA cleavage between them, we performed quantitative analysis of both the 3 Ј-OH and the 5 Ј-OH ends of DNA strand breaks via in situ nick-end labeling (ISEL) combined with transmission electron microscopy (TEM) of both heat-induced apoptosis and necrosis in mouse B-cells derived from a lymphoma cell line. To detect the 5 Ј-OH ends, the 3 Ј-P ends located on the opposite side holding the 5 Ј-OH ends were dephosphorylated into 3 Ј-OH ends with alkaline phosphatase. As assessed by statistical analysis of both the 3 Ј-OH and the 5 Ј-OH ends, their labeling densities were significantly higher in both the apoptotic and the necrotic cells in the early stage than in control cells. The labeling densities increased during the apoptotic and necrotic processes, except for a decrease in the density of the 3 Ј-OH ends in necrotic cells in the late stages. Therefore, DNA degradation in both necrosis and apoptosis provides early evidence for these processes, and both apoptosis and necrosis may share at least the first steps of DNA degradation pathways. (J Histochem Cytochem 46:1051-1059, 1998)

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Researchers are increasingly recognizing anime and manga as worthy of scholarly examination. However, relatively little research examines how fans synthesize the cultural content of anime. This paper provides an analysis of representations of race/ethnicity and gender in two televised anime, and contrasts the understandings of scholars to fans. As anime can weave together images from Japanese culture, other cultures, as well as fantasy, anime presents many faces to fans. Fans do not necessarily see all of these faces at once, and they interpret the cultural content of anime differently. As a result, anime has the potential to generate different types of cultural influence.

A cDNA clone encoding an endo-1,4-beta-glucanase from a rumen fungus, Neocallimastix frontalis MCH3, was isolated. The nucleotide sequence showed that the gene, celA, encoded a multidomain enzyme containing a family 5 catalytic domain and a reiterated sequence that is involved in the association of a multienzyme complex, the cellulosome. The enzyme expressed in Escherichia coli showed the highest activity against carboxymethylcellulose at 40 degrees C and pH 8.5.