Molecular Characterization of Cryptosporidium Isolates Obtained from Human and Bovine Infections in Japan

Cryptosporidiumポリスレオニン遺伝子のPCR/RFLP分析により、わが国で分離されたヒト由来Cryptosporidium22株は、ヒト型C.parvum(genotype1)、動物型C.parvum(genotype2)、トリ型C.meleagridis(genotype3)の3遺伝子型に明瞭に型別された。ヒト由来genotype3のC.meleagridis分離株は、Cryptosporidium18S　rRNA遺伝子のシークエンス分析により同定され、その存在が本邦で初めて確認された

A Pilot Study for the Detection of Protozoa Infections of the Gut at Autopsy

In order to investigate the incidence of latent infections by parasites within the human digestive tract, we examined fresh stool samples from the colon of 31 patients (37-90 years, median age 71; 26 men and 5 women) collected within 12 hours of death. These subjects had been admitted to a university hospital in Yokohama, Japan, and died between April 2007 and December 2008 from causes other than parasitosis. Stool samples were fixed and stained for microscopic analysis, and PCR analysis for Entamoeba histolytica was performed for the parasite-positive samples. Results showed that ten out of 31 subjects were infected by E. histolytica only, one subject was infected by Giardia intestinalis only, and four subjects were infected by both E. histolytica and G. intestinalis. These findings are in contrast to conventional theories concerning general parasite infection in Japan, and indicate continuous or latent infection within the human digestive tract. The presence of pathogens such as E. histolytica and G. intestinalis in elderly or immuno-compromised patients is a serious issue and warrants further attention as a public health issue, particularly in relation to its mode of transmission

Effects of oxygen concentration on the proliferation and differentiation of mouse neural stem cells in vitro.

BACKGROUND AND PURPOSE: Cerebral ischemia is known to elicit the activation of neural stem cells (NSCs); however its mechanism is not fully determined. Although oxygen concentration is known to mediate many ischemic actions, there has been little attention given to the role of pathological oxygen changes under cerebral ischemia on the activation of NSCs. We investigated the effects of various oxygen concentrations on mouse neural stem cells in vitro. METHODS: NSCs were cultured from the ganglionic eminence of fetal ICR mice on embryonic day 15.5 using a neurosphere method. The effects of oxygen concentrations on proliferation, differentiation, and cell death of NSCs were evaluated by bromodeoxyuridine (BrdU) incorporation, immunocytochemistry, and TUNEL assay, respectively. RESULTS: The highest proliferation and the neuronal differentiation of the NSCs were observed in 2% oxygen, which yielded significantly higher proportions of both BrdU-labeled cells and Tuj1-positive cells when compared with 20% and 4% oxygen. On the other hand, the differentiation to the astrocytes was not affected by oxygen concentrations, except in the case of anoxia (0% oxygen). The cell death of the NSCs increased in lower oxygen conditions and peaked at anoxia. Furthermore, the switching of the neuronal subtype differentiation from GABA-positive to glutamate-positive neurons was observed in lower oxygen conditions. CONCLUSIONS: These findings raise the possibility that reduced oxygen levels occurring with cerebral ischemia enhance NSC proliferation and neural differentiation, and that mild hypoxia (2% oxygen), which is known to occur in the ischemic penumbra, is suitable for abundant neuronal differentiation

Draft Genome Sequence of High-Temperature-Adapted Protochlamydia sp. HS-T3, an Amoebal Endosymbiotic Bacterium Found in Acanthamoeba Isolated from a Hot Spring in Japan

Here, we report the draft genome sequence of high-temperature-adapted Protochlamydia sp. strain HS-T3, an environmental chlamydia. This bacterium is an amoebal endosymbiont, found in Acanthamoeba isolated from a hot spring in Japan. Strain HS-T3 readily grew in mammalian cells at 37°C, a characteristic not previously reported for environmental chlamydiae

Seasonal Fluctuation of Acanthamoeba spp. Contamination in Water Containers Placed Indoors and Outdoors

The medical importance of free living amebas has been increasing as a worldwide problem. In Japan amebic keratitis caused by Acanthamoeba has caught the attention of ophthalmologists due to increasing risk of infection for soft-contact lens users. In the present work we examined the process of Acanthamoeba contamination in water placed indoors and outdoors under different conditions in Nagasaki city, Japan. The most frequently contaminated water was in coverless outdoor containers in the spring, and the next was in similar conditions, but in the autumn. The highest contamination of indoor water in coverless containers was found in the summer although the frequency was much lower than outdoors. When the containers were covered, complete protection for water bodies from Acanthamoeba contamination was obtained indoors, and nearly complete outdoors. Electrophoretic patterns of mitocondrial DNA fragments digested by two restriction enzymes indicated that Acanthamoeba contaminants seemed to be season-specific although the number of examined isolates was very small