Analysis of Slow Hyperpolarizing Potentials in Frog Taste Cells Induced by Glossopharyngeal Nerve Stimulation

Chemical Senses, 29,     

Long-Term Trends in Matrilineal Inbreeding Among the Japanese Macaques of Arashiyama B Troop

In a long-term study of sexual behavior in Japanese macaques, we found that matrilineal inbreeding accounted for 2.9% of the copulations recorded for the Arashiyama B troop during 7 mating seasons between 1968 and 1984. Of the 906 copulatory dyads, 46 (5.1%) occurred among kin. Close matrilineal kin dyads (r = 1/2–1/8, 1.1% of the total of copulatory dyads) strongly avoided matrilineal inbreeding, but for remote kin dyads (r > 1/8, 4.0% of the total) the tendency was weaker in some years. Among the possible determinants of matrilineal inbreeding, we found that it tended to occur among younger and lower-ranking males as an effect of troop demographic changes. There is no significant association between female rank and matrilineal inbreeding. Our results are consistent with the hypothesis that different degrees of kin relatedness are discriminated by individuals with respect to mate choice.     

Fine structure and lectin histochemistry of the apical surface of the free neuromast of Lampetra japonica

The surface coat, ciliary process, and microvilli of the lamprey neuromast were examined with electron microscopy after tannic acid prefixation and lectin histochemistry. The neuromast was found to exist in the form of a dermal mound with a furrow in the middle. On the bottom of the furrow, the hair cell was characterized by a kinocilium and 15–20 stereocilia, arranged along the longitudinal axis of the furrow. Spanning structures were demonstrated between the kinocilium and stereocilia as well as between stereocilia. The surface coat, enhanced by tannic acid prefixation, was particularly rich over the surface of the supporting cell; by contrast, it was thin over the hair cell. Some lectins (PNA, GS-I, SBA, WGA) showed affinity to the surface coat of the supporting cell as well as the hair cell, and the others (RCA-I, MPA, ConA) showed affinity only to the supporting cell. These differences in the structure and affinities of the surface coat suggest an extracellular milieu highly specialized for the hair cell in this particular form of the mechanoreceptor.     

The relationship between female rank and reproductive parameters of the ringtailed lemur: a preliminary analysis

We used data from a 13-year field study of wild ringtailed lemurs to analyze the relationship between female rank and reproductive parameters. In medium and small groups there were no significant differences in birth rate, infant mortality rate, and the number of surviving infants between the female rank categories. On the other hand, in large sized groups low-ranked females had a smaller number of surviving infants than middle-ranked females. This suggests that in large sized groups, within-group competition lowered the values of reproductive parameters of low-ranked females. On the other hand, high and low-ranked females of small sized groups tended to have a smaller number of surviving infants than high-ranked females of medium sized groups and middle-ranked females of large sized groups. Between-group competition should lower the values of their reproductive parameters. In sum, these results fit the expectation from Wrangham’s (1980) inter group feeding competition model.     

The enhancing action of D-galactosamine on lipopolysaccharide-induced nitric oxide production in RAW 264.7 macrophage cells

The effect of D-galactosamine (D-GalN) on nitric oxide (NO) production in lipopolysaccharide (LPS)-stimulated RAW 264.7 macrophage cells was examined. D-GalN augmented the production of NO, but not tumor necrosis factor (TNF)-alpha in LPS-stimulated RAW 264.7 cells. Pretreatment of D-GalN augmented the NO production whereas its post-treatment did not. D-GalN augmented the NO production in RAW 264.7 cells stimulated with either TNF-alpha and interferon-gamma. The augmentation of LPS-induced NO production by D-GalN was due to enhanced expressions of an inducible type of NO synthase mRNA and proteins. Intracellular reactive oxygen species (ROS) were exclusively generated in RAW 264.7 cells stimulated with D-GalN and LPS. Scavenging of intracellular ROS abrogated the augmentation of NO production. It was therefore suggested that D-GalN might augment LPS-induced NO production through the generation of intracellular ROS.     

Differences in surface phenotype and mechanism of action between alloantigen-specific CD8+ cytotoxic and suppressor T cell clones

We have previously demonstrated that fresh CD8+ T cells proliferate in response to autologous, alloantigen-primed CD4+ T cells, and differentiate into Ts cells, which inhibit the response of fresh T cells to the primary allogeneic stimulator cell but not irrelevant stimulators. Although such Ts do not have discernible cytolytic activity, like classical cytotoxic T cells (Tc) they express CD3 and CD8 on their surface and function in a class I MHC-restricted manner. Our study was an attempt to compare the surface phenotype and mechanism of action of Ts and Tc clones derived from the same individual. Ts clones were generated from donor JK by repeated stimulation of CD8+ T cells with an autologous CD4+ T inducer line specific for an allogeneic lymphoblastoid cell line (LCL). These clones were noncytolytic for either the inducer line or the allogeneic stimulator LCL. Tc clones, generated by direct stimulation of JK CD8+ T cells with the same allogeneic LCL, mediated potent, alloantigen-specific cytolysis. All Tc clones were alpha, beta TCR+, CD3+, CD4-, CD8+, CD11b-, and CD28+. Ts clones were also alpha, beta TCR+, CD3+, and CD8+, but in contrast to Tc clones, Ts clones were CD11b+ and CD28-. When added to MLR both Ts and Tc clones inhibited the response of fresh JK CD4+ T cells to the original but not irrelevant allogeneic LCL. However, Ts inhibited the response of only those CD4+ T cells that shared class I)MHC determinants with the Ts donor, whereas Tc inhibited the response of CD4+ T cells from all responders, regardless of HLA type. Pretreatment of Ts clones with mAb to CD2, CD3, or CD8 blocked suppression, whereas similar pretreatment of Tc clones blocked cytotoxicity in 4-h 51Cr release assays but had no effect on Tc-mediated suppression of the MLR. These results suggest that both Ts and Tc clones can inhibit the MLR but they do so through different mechanisms. Moreover, the maintenance of distinct surface phenotypes on these long term clones suggests that Ts may be a distinct sublineage of CD8+ T cells rather than a variant of CD8+ Tc.     

Novel relationship between the antifungal activity and cytotoxicity of marine-derived metabolite xestoquinone and its family

Xestoquinone and related metabolites (the xestoquinone family) occur in marine sponges and are known to show a variety of biological activities. In this study, the first comprehensive evaluation of antifungal activity was performed for xestoquinone and nine natural and unnatural analogues in comparison with their cytotoxicity. The cytotoxicity against two human squamous cell carcinoma cell lines, A431 and Nakata, indicated that the terminal quinone structure of the polycyclic molecules was important (xestoquinone, etc.) and that the presence of a ketone group at C-3 of the opposite terminus dramatically diminished the activity (halenaquinone, etc.). In contrast, a ketone group at C-3 enhanced the antifungal activity against the plant pathogen, Phytophthora capsici, regardless of the presence of a quinone moiety. The cytotoxicity and antifungal activity of the xestoquinone family were negatively correlated with each other.