Studies on Gonococcal Infection

Macrophages from mice were infected with Neisseria gonorrhoeae type 1 cells, and their ultrastructure was studied by electron microscopy. The macrophages showed various stages of engulfment and digestion of gonococci 2 hr after infection. Infected macrophages seemed to develop pseudopodia for phagocytosis, and could engulf more than 30 gonococcal cells. Some engulfed bacteria appeared morphologically intact, while others appeared lysed and some structures resembling the L form of N. gonorrhoeae were also seen. These observations suggest that gonococcal cells may be able to survive intracellularly with normal or altered forms of morphology, and that macrophages containing these bacteria may disseminate gonococcal infection in man.     

Female reproductive cycles in the northernmost populations of the two gekkonid lizards,Hemidactylus frenatus andLepidodactylus lugubris

Lepidodactylus lugubris, a parthenogenetic gekkonid lizard of possible tropical origin, occurs on Kita-Daitojima Island of the Ryukyu Archipelago and lays eggs almost throughout the year. The oviposition season of the sympatric population of another primary tropical, but bisexual gecko,Hemidactylus frenatus, is confined to between April and September. Laboratory experiments indicate that the hatching ratio of the egg reduces with the decrease of incubation temperature in both species. Some eggs ofL. lugubris develop at 14°C of ambient temperature, wheras eggs ofH. frenatus always die at temperatures of 18°C or lower. Examinations of stomach contents and fat body mass in the monthly samples suggest that food availability is not severely low for the geckos even during the winter, rejecting the previous assumption that food stress suppresses vitellogenesis inH. frenatus. No other environmental factors that may induce reproductive seasonality as phenotypic physiological responses were detected either. Tropical populations ofH. frenatus andL. lugubris are known to lack distinct annual reproductive cyclicity. Thus, it is probable that the East AsianH. frenatus has evolved the winter quiescence of reproduction, presumably due to the poor embryonic tolerance of low temperatures. The absence of such seasonality in the sympatricL. lugubris seems to be attributable to its clonal nature which predicts the low genetic variability of the population from the colonization stage.     

Correction: Cooperative den maintenance between male Japanese badgers that are delayed dispersers and their mothers

Journal of Ethology -     

Heterogeneity of molybdate-stabilized, nontransformed glucocorticoid receptor from rat liver

Nontransformed glucocorticoid receptor stabilized with sodium molybdate exists as the heterogeneous forms which have slight differences in net charges and sedimentation coefficients. These differences could be detected by sequential analyses with DEAE-Sephacel chromatography and glycerol gradient centrifugation. The heterogeneity in the nontransformed receptor appears to be caused by the association of an acidic component(s) with the transformed receptor.     

Plural infection by Salmonella O7 group that hospital infection was doubted]

In Aug, 2002 (heisei 14), a 74-year-old male inpatient had been complaining of fever and diarrhea. A feces culture test was done and a few colonies were discovered and were suspected to be Salmonella O7 and were later confirmed to be as such. A further investigation and interviewing of patients was undertaken. As a result we suspected an internal infection, and did feces culture tests with 7 out of 15 inpatients who had recently had a stomachache or diarrhea and were able to be tested, and 2 discharged patients. Salmonella O7 was detected by direct fulguration in 4 of them and by enrichment in 2, for a total of 6 out of 9 patients. We considered the source to be food poisoning originating in hospital meals and in adherence to the Food Hygiene Law, turned to the proper authorities, which was the Nagaoka Board of Health, for administrative guidance. To search for the cause of this infection, environmental inspections of the patients' rooms and hospital kitchen were undertaken. Further interviews with the patients were also done but they cleared neither the infection source nor the infection route. Even without a genic test, the biotypes were all the same as 53525040. This was discovered by an Autoscan 4 (DADE BEHRING) and the result gave a strong suspicion of an internal infection. The Nagaoka Board of Health was of the opinion that there was a low possibility of the hospital meals being a source of the infection. The reasons were because the diarrhea did not present at the same time among all the patients, there were a distinct few cases of diarrhea among the hospital meal fed patients, and there were no contamination factors found by their investigation of the staff or the system for preparing the meals. Three patients were given an antimicrobic and the measures for training and educating the staff, maintaining a clean environment and fighting infection were re-examined. The case was brought to its conclusion after about 40 days.     

Relict distribution of Microhyla (Amphibia: Microhylidae) in the Ryukyu Archipelago: High diversity in East Asia maintained by insularization

The Ryukyu Archipelago, located at the southwestern part of Japan, is known as a group of continental islands and harbours many endemic taxa, supposedly reflecting its fairly long isolation from the Eurasian continent, Taiwan and the Japanese main islands. Microhyla okinavensis has been known as an endemic member of the terrestrial fauna of this archipelago. Molecular phylogenetic analyses using samples from nearly all island populations of the species and representative samples of other east Asian congeneric species revealed that M. okinavensis consists of four distinct subclades, of which the Amami, Okinawa and Miyako subclades, though exhibiting distinct genetic differentiations from each other, formed a monophyletic group (clade A). The remaining Yaeyama subclade was exclusively sister to M. mixtura from inland China, forming another monophyletic group (clade B), rendering M. okinavensis in the current definition paraphyletic. These results, as well as estimated dates of divergence from related taxa, indicate that M. okinavensis actually includes more than one distinct species. The results indicate that M. okinavensis and M. mixtura are relict species with disjunct distributions which had been most probably caused by invasion of M. fissipes in intervening areas.