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Prion diseases are a family of neurodegenerative zoonotic foodborne disorders. Although prions can be transmitted orally, the mechanism by which prions are incorporated into the intestine remains unclear. Our previous studies have shown that an abnormal isoform of prion protein (PrP(Sc)), which is the main component of prions, was efficiently incorporated into the intestine in suckling mice but not in weaned mice. Furthermore, suckling SCID mice lacking maternal antibodies showed decreased uptake of PrP(Sc) into the intestine compared with suckling wild-type mice, while the lack of PrP(Sc) uptake into the intestine of suckling SCID mice was rescued by the oral administration of IgG. These findings raise the possibility that the neonatal Fc receptor (nFcR), which contributes to the uptake of maternal antibodies into the intestine, plays a role in PrP(Sc) incorporation into the intestine. The present immunohistochemical study further showed that the FcR blocker Z-ε-aminocaproic acid (ZAA) inhibited PrP(Sc) incorporation into the intestinal villi of suckling mice, supporting the above mentioned concept. Therefore, our findings provide strong evidence that nFcR and maternal antibodies are involved in PrP(Sc) incorporation into the intestine before the weaning period.

The article deals with a study which assessed the prevalence of avian haemosporidia of genera Plasmodium, Haemoproteus and Leucocytozoon among birds and mosquitoes on Tsushima Island, Japan. Topics discussed include information on species of mosquitoes collected in this study, information on varieties of avian blood parasites in wild birds, and proof of direct contact between infected birds and mosquitoes inhabiting the island.

Abstract  One of vector-borne avian protozoa, Leucocytozoon lovati, has been found in the Japanese rock ptarmigans (Lagopus mutus japonicus), the endangered bird species distributed in the alpine regions in Japan. Vector arthropod species of L. lovati has also been estimated as Simuliidae black flies distributed in the same habitat of the host bird, however, possible blood meals of the black flies were not identified yet. To reveal host animals of black flies, we estimated the blood resources by using molecular techniques. Black flies were collected at Mt. Chogatake, one of the alpine regions of Japan in which Japanese rock ptarmigans live in June 2005. The analyzed 144 specimens were morphologically identified into five species including Simulium japonicum (n = 87), Prosimulium hirtipes (n = 48), Prosimulium yezoense (n = 3), Twinnia japonensis (n = 3), and Cnephia mutata (n = 3). Individually extracted DNA from the black flies was subjected to polymerase chain reaction (PCR) amplification targeting the partial mitochondrial cytochrome b gene of birds or mammals to identify the blood meals. Of 144 black flies examined, 34 specimens were PCR positive for avian hosts (23.6%). No mammalian-derived bloods were detected from the samples studied through. Sequences amplified from 11 black flies consist of S. japonicum, P. hirtipes, and C. mutata showed high similarity to that of the Japanese rock ptarmigan. Therefore, present results conclusively suggest that these three species of black flies might suck the bloods of Japanese rock ptarmigans and could be the vector for L. lovati infection among this endangered bird species of Japan. [ABSTRACT FROM AUTHOR]

Abstract  Probable arthropod vectors of avian blood protozoa, Leucocytozoon lovati, were collected in the alpine regions of Japan, the habitats of the host birds of Japanese rock ptarmigan (Lagopus mutus japonicus). Seven alpine regions of Japan, Asahidake, Chogatake, Tateyama, Jiigatake, Norikura, Kitadake, and Senjyogatake were investigated for black fly collection during 2004 to 2007. The collected 490 insects were morphologically identified as six species of female black flies, including Prosimulium hirtipes group (n = 59), Prosimulium mutata (n = 13), Prosimulium yezoense (n = 10), Similium japonicum (n = 359), Similium uchidai (n = 39), and Twinnia japonensis (n = 10). Extracted DNAs from individual black fly species were utilized for the amplification of the partial mitochondrial cytochrome b gene sequences of Leucocytozoon lovati previously reported. Four S. japonicum, two S. uchidai, and two P. hirtipes group studied were positive for the nested PCR among 490 black flies collected (1.6%; 8/490). All amplified sequences from the black flies were completely identical to those of L. lovati previously detected from Japanese rock ptarmigan. Our results suggest that at least three species of black flies, S. japonicum, S. uchidai, and P. hirtipes group, studied in this area could be regarded as potential vectors for L. lovati in the rock ptarmigan. This is the first detection case of Leucocytozoon from black flies of Japan. [ABSTRACT FROM AUTHOR]

The side effects of hyperbaric oxygen (HBO) treatment, such as oxidative stress and oxygen toxicity, have long been of interest. However, there are no comprehensive studies evaluating such toxic effects in diabetes mellitus (DM). The purpose of this study was to determine the effects of HBO on glucose homeostasis and histological changes in pancreatic β-cells of experimentally induced diabetic rats. A total of 24 male Wistar rats were randomly divided into 4 groups: 1) Control group, no diabetic induction without HBO treatment; 2) HBO group, exposed to 100% oxygen at 2.8 ATA (atmosphere absolute) for 2 h once daily, for 7 days; 3) DM group, diabetes induced by streptozotocin (STZ) injection; and 4) DM + HBO group, received both STZ injection and HBO exposure. HBO treatment, with clinically recommended pressures and duration of therapy, was started on day 5 after STZ injection, when the blood glucose levels were significantly increased. After the last HBO treatment, the pancreatic tissues were immunostained to measure the areas of insulin immunoreactive β-cells in the islets of Langerhans. The blood glucose increased significantly following exposure to HBO, with the highest levels achieved in rats, which had been treated with both HBO and diabetic induction. The area populated with insulin immunoreactive β-cells decreased significantly following diabetic induction and/or HBO exposure, with the smallest area in DM + HBO group. Thus, HBO exposure enhanced the cytotoxic effect of STZ in the β-cells of the pancreas. HBO should be cautiously employed in diabetic patients. ──── hyperbaric oxygen; streptozotocin; diabetic rat; glucose toxicity; oxidative stress. [ABSTRACT FROM AUTHOR]

Abstract  We analyzed extra chromosomal genomes of avian blood protozoa, Leucocytozoon caulleryi. One of the genomes, the mitochondrial genome was completely sequenced resulting 5,959 bp in length. This genome contained the identical gene organization and contents to that of other avian blood protozoa previously analyzed: three functional genes for cytochrome c oxidase subunit I, III, and cytochrome b with following sets of discontinuous and scrambled 15 ribosomal subunit RNA genes. In addition, the mitochondrial genome was estimated to have the tandem repeated structure as well as previously found in avian Plasmodium species. Furthermore, we found partial gene sequences of apicoplast DNA, another extra chromosomal genome, from L. caulleryi. These sequences were estimated as partial caseinolytic protease C and elongation factor Tu A genes. This report is the first description of two extra chromosomal genomes of L. caulleryi. [ABSTRACT FROM AUTHOR]

Abstract??We analyzed mitochondrial genomes of two avian malaria protozoa,Plasmodium gallinaceumandPlasmodium juxtanucleare. Both mitochondrial genomes were estimated to be 6,002 and 6,014?bp in length, respectively, and to have the identical gene organization and contents to that of otherPlasmodiumspecies previously analyzed; three functional genes for cytochromecoxidase subunit I, III, and cytochrome (cytb), with following sets of discontinuous and scrambled 15 ribosomal subunit RNA (rRNA) genes. Similarities of the three protein-coding genes showed closer relationship within avian malaria protozoa rather than mammalianPlasmodiumspecies. In addition, we showed the tandem repeated structure of each mitochondrial genome of bothP. gallinaceumandP. juxtanucleareas well as previously found in mammalianPlasmodiumspecies. This study revealed the complete sequences and structure of the mitochondrial genomes of avian malaria protozoa for the first time. [ABSTRACT FROM AUTHOR]