Daisuke Fukui

Particle-Induced X-ray Emission Analysis of Elements in Plasma from Wild and Captive Sea Turtles (Eretmochelys imbricata, Chelonia mydas, and Caretta caretta) in Okinawa, Japan

The aim of this study was to evaluate the reliability of direct determination of trace and major element concentrations in plasma samples from wild (six hawksbill, nine green, and nine loggerhead) and captive sea turtles (25 howksbill, five green, and three loggerhead) in Okinawa, Japan. The particle induced X-ray emission method allowed detection of 23 trace and major elements (Al, As, Br, Ca, Cl, Cr, Cu, Fe, Hg, K, Mg, Mn, Mo, Ni, P, Pb, S, Se, Si, Sr, Ti, Y, and Zn). The wild sea turtles were found to have high concentrations of As and Pb in plasma compared with captive, but there were no significant changes in the Al and Hg concentrations. Loggerhead sea turtles were found to have significantly higher accumulation of As and Pb in plasma in comparison to other species. These findings may be useful when adjusting environmental and species-related factors in severely polluted marine ecosystems. Our results indicate that measuring the plasma As and Pb concentrations in wild sea turtles might be of help to assess the level of pollution in marine ecosystems, keeping in mind that loggerhead sea turtles had been shown to have higher levels of As and Pb in plasma.

Mass mortality of Eurasian Tree Sparrows (Passer montanus) from Salmonella Typhimurium dt40 in Japan, winter 2008-09.

Abstract An outbreak of salmonellosis in wild passerines caused mass mortality of Eurasian Tree Sparrows (Passer montanus) in Hokkaido, Japan, 2005–06; however, the etiology was poorly understood. In winter 2008–09, sparrow mortality again occurred in Hokkaido, and 202 deaths in 100 incidents at 94 sites were reported. We conducted a comprehensive investigation to evaluate the cause and impact on sparrow populations. We collected 26 carcasses at 13 sites, including a zoological park. In addition, Salmonella screening of zoo animals was conducted as a biosecurity measure. Salmonella Typhimurium was isolated from multiple organs in all examined sparrows; they were diagnosed with septicemic salmonellosis. Eleven sites (85%) were related to wild bird feeding and six of eight sparrow fecal samples, including from the zoo, were S. Typhimurium-positive. No infection was detected in zoo animals. Isolates belonged to three phage types: DT40 (88%), DT110 (8%), and DT120 (4%). Pulsed-field gel electrophoresis patterns were the same in all isolates, regardless of phage type. Biochemical characteristics and antibiotic-resistance profiles of DT40 were similar in all isolates, indicating a single origin. The mortality was likely associated with that in 2005–06 because the isolates had the same profiles. Tissue levels of sodium, calcium, and magnesium (the main components of chemical deicer suspected to be the major cause of poisoning deaths in 2005–06 mortality) were not higher in the affected sparrows. We conclude that an emerging epidemic infection with S. Typhimurium DT40 related to bird feeding was the cause of sparrow mortality in 2008–09 and suggest that this causative strain is host-adapted to sparrows in Japan. The mortality might have had some impact on the local population, but its influence was limited.

The Effects of Frequent Electroejaculation on the Semen Characteristics of a Captive Siberian Tiger (Panthera tigris altaica)

Artificial insemination (AI) can help to avoid inbreeding and genetic degeneration for sustaining genetically healthy populations of endangered species in captivity. Collection of a sufficient quantity of viable sperm is an essential first step in the AI process. In the present study, we examined the effects of frequent electroejaculation on semen characteristics in a Siberian tiger. We collected semen in all 17 trials during 6 breeding seasons (6 years). The mean number of sperm and the percentage of motile sperm were 294.3 ± 250.2×106/ejaculate and 82.4 ± 11.4%, respectively. The number of motile sperm tended to increase during frequent electroejaculation in the same breeding season. Semen collection by electroejaculation can be performed effectively up to the fourth sequential ejaculate, which contained the most sperm in the study. In conclusion, frequent collection of sperm by electroejaculation from tigers may be effective for collection of a large number of motile sperm.

Accessory corpora lutea formation in pregnant Hokkaido sika deer (Cervus nippon yesoensis) investigated by examination of ovarian dynamics and steroid hormone concentrations

Generally, sika deer conceive a single fetus, but approximately 80% of pregnant females have two corpora lutea (CLs). The function of the accessory CL (ACL) is unknown; moreover, the process of ACL formation is unclear, and understanding this is necessary to know its role. To elucidate the process of ACL formation, the ovarian dynamics of six adult Hokkaido sika deer females were examined ultrasonographically together with peripheral estradiol-17β and progesterone concentrations. ACLs formed in three females that conceived at the first estrus of the breeding season, but not in those females that conceived at the second estrus. After copulation, postconception ovulation of the dominant follicle of the first wave is induced by an increase in estradiol-17β, which leads to formation of an ACL. A relatively low concentration of progesterone after the first estrus of the breeding season is considered to be responsible for the increase in estradiol-17β after copulation.

A soluble envelope protein of endogenous retrovirus (FeLIX) present in serum of domestic cats mediates infection of a pathogenic variant of feline leukemia virus.

T-lymphotropic feline leukemia virus (FeLV-T), a highly pathogenic variant of FeLV, induces severe immunosuppression in cats. FeLV-T is fusion defective because in its PHQ motif, a gammaretroviral consensus motif in the N terminus of an envelope protein, histidine is replaced with aspartate. Infection by FeLV-T requires FeLIX, a truncated envelope protein encoded by an endogenous FeLV, for transactivation of infectivity and Pit1 for binding FeLIX. Although Pit1 is present in most tissues in cats, the expression of FeLIX is limited to certain cells in lymphoid organs. Therefore, the host cell range of FeLV-T was thought to be restricted to cells expressing FeLIX. However, because FeLIX is a soluble factor and is expressed constitutively in lymphoid organs, we presumed it to be present in blood and evaluated its activities in sera of various mammalian species using a pseudotype assay. We demonstrated that cat serum has FeLIX activity at a functional level, suggesting that FeLIX is present in the blood and that FeLV-T may be able to infect cells expressing Pit1 regardless of the expression of FeLIX in vivo. In addition, FeLIX activities in sera were detected only in domestic cats and not in other feline species tested. To our knowledge, this is the first report to prove that a large amount of truncated envelope protein of endogenous retrovirus is circulating in the blood to facilitate the infection of a pathogenic exogenous retrovirus.

Implementation of dual transmission function for remote vehicle controls

Network-supported remote vehicle control is expected to improve efficiency in the future society. Our research target is to develop a cost-effective real-time control technique using the broadband wireless network infrastructure. To improve the transmission performance using broadband wireless access networks, we have already proposed dual transmission protocol (DTP) that uses independent two transmission channels simultaneously. In this paper, we show experimental evaluations of DTP implementation. Those evaluations show improved frame loss ratio of video signals and enhanced controllability of remotely controlled vehicle (Internet-connected model car). Those results indicate DTPs effectiveness and feasibility.

Timing of Puberty and Its Relationship with Body Growth and Season in Male Raccoons (Procyon lotor) in Hokkaido

Abstract The raccoon (Procyon lotor), indigenous to North America, has naturalized in Japan as an invasive alien species, having been introduced into the country in the 1970s. In Hokkaido, the northernmost island of Japan, feral raccoons have been increasing in number and spreading throughout the island. The age at the onset of puberty for raccoons is important for estimating individual lifetime reproductive success and population growth. The present study investigated the timing of and potential factors affecting the onset of puberty in male raccoons in Hokkaido. External characteristics and histology of testes were studied in 151 male feral raccoons and in 1 captive juvenile. For the majority of feral yearling raccoons, prepubertal development began in May, and spermatozoa production began in October prior to their second mating season. However, some larger juveniles attained puberty during the juvenile period. The captive juvenile, which was fed throughout the winter, attained puberty only 11 months after birth. These results suggest that if male raccoons can achieve enough body growth before the first mating season, puberty can be attained early. In both juveniles and yearlings, spermatozoa production was only observed after autumn. This timing coincided with the recrudescence of seasonally active spermatogenesis in adult males. Therefore, attaining puberty in male raccoons appears to require both adequate body nutrient development and several environmental factors that control seasonal testicular changes.

AN EPIZOOTIC OF EMERGING NOVEL AVIAN POX IN CARRION CROWS (CORVUS CORONE) AND LARGE-BILLED CROWS (CORVUS MACRORHYNCHOS) IN JAPAN

Abstract In 2006–10, an epizootic of emerging avian pox occurred in Carrion Crows (Corvus corone) and Large-billed Crows (Corvus macrorhynchos), leading to mortality of juvenile crows in Hokkaido, the northernmost island of Japan. We diagnosed 27 crows with proliferative skin lesions (19 carcasses and eight biopsied cases [one in zoo captivity]) as avian pox clinically, histopathologically by detection of Avipoxvirus-specific 4b core protein (P4b) gene, and epidemiologically. The fatal cases demonstrated intensively severe infection and aggressive lesions with secondary bacterial infection. Since the first identification of avian pox in Sapporo, Japan, in 2006, the frequency of mortality events has increased, peaking in 2007–08. Mortalities have subsequently occurred in other areas, suggesting disease expansion. In Sapporo, prevalence of avian pox evaluated by field censuses during 2007–12 was 17.6% (6.6–27.2%), peaked during 2007–08 and 2008–09, and then decreased. All diseased crows were juveniles, except for one adult. The number of crows assembling in the winter roosts had been stable for >10 yr; however, it declined in 2007–08, decreased by about 50% in 2008–09, and recovered to the previous level in 2009–10, correlated with the avian pox outbreak. Thus, avian pox probably contributed to the unusual crow population decline. All P4b sequences detected in six specimens in Sapporo were identical and different from any previously reported sequences. The sequence detected in the zoo-kept crow was distinct from any reported clades, and interspecies transmission was suspected. This report demonstrates an emerging novel avian pox in the Japanese avifauna and in global populations of Carrion Crows and Large-billed Crows. Longitudinal monitoring is needed to evaluate its impact on the crow population.

Metabolic Alkalosis due to Feeding Chicks in Breeding Adélie Penguins Pygoscelis adeliae under Natural Conditions

Prolonged abnormal vomiting causes metabolic alkalosis. Many seabirds are known to feed their chicks by regurgitation. We hypothesized that metabolic alkalosis occurs in seabirds even under natural conditions during the breeding season. Adélie penguins Pygoscelis adeliae feed their chicks by regurgitating food for 50–60 d until the chicks fledge. In this study, the concentrations of Cl−, HCO3−, Na+, K+, pH, and Pco2 in the blood of breeding Adélie penguins were measured throughout the chick‐rearing season. The pH of penguin venous blood shifted from 7.54 in the guarding period to 7.47 in the crèche period. Decreasing Cl− and increasing HCO3− blood concentrations in parents were associated with increasing mass of their brood in the guarding period, the early phase of the rearing season, indicating that regurgitating to feed chicks causes loss of gastric acid and results in relative metabolic alkalosis. The inverse trend was observed during the crèche period, the latter phase of the rearing season, when parents spent more time at sea and have fewer opportunities for gastric acid loss. This was assumed to be the recovery phase. These results indicate that regurgitation might cause metabolic alkalosis in breeding Adélie penguins. To our knowledge, this is the first report to indicate that seabirds exhibit metabolic alkalosis due to regurgitation to feed chicks under natural conditions.

A case study of the molecular genetical diagnosis of a small African elephant (Loxodonta sp.) "Nana" kept at Asahiyama Zoo

The African elephant genus Loxodonta consists of two distinct species, savanna elephants (Loxodonta africana, Blumenbach 1797) (Fig. 1A) and forest elephants (Loxodonta cyclotis, Matschie 1900) (Fig. 1B) (Grubb et al. 2000; Roca et al. 2001, 2005). The savanna elephants are widely distributed in bush areas of the sub-Sahara and their body sizes are larger than those of the forest elephants. On the other hand, the forest elephants inhabit tropical rain forest areas of Central Africa and the coastline of the Gulf of Guinea in West Africa (Nowak 1999; Grubb et al. 2000). There are several morphological differences between them (e.g., the shape of the cranium, ears, tusks, body build and so on; Grubb et al. 2000). However, occasionally there are individuals for which it is difficult to identify the species (Groves and Grubb 2000; Debruyne 2005). The forest elephants are endangered and adequate breeding plans in zoological gardens are urgently needed. Therefore, accurate identifications of the species are important. The conventional method of species identification used in Japanese zoological gardens, however, has some problems. A small female Loxodonta named “Nana” (died on April 21st, 2006) was being kept as a forest elephant at Asahiyama Zoo (Asahikawa City, Hokkaido, Japan) (Fig. 1C). She was a wild-born individual (geographical origin unknown), and was purchased in 1980 at the approximated age of 2–3 years old. At first, she was considered to be a savanna elephant, but later features attributed to a forest elephant were identified in her morphological characters. Firstly, her body size was small. Secondly, she had the same hoof structure as forest elephants (5 hooves on the forelimb and 4 on the hindlimb). Thirdly, her ears overlap across the top of the neck. From these reasons, she was identified as a forest elephant. But uncertainties to this identification remained. For instance, it is generally said that savanna elephants have 4 hooves on the forelimb and 3 on the hindlimb (Nowak 1999), and forest elephants have more hooves on both the forelimb and hindlimb (Debruyne 2005). However, it is known that there are variations among the African elephants (Sikes 1971; Grubb et al. 2000). The savanna elephants have 4 or 5 hooves on the forelimb, and 3 to 5 on the hindlimb. Corresponding numbers for the forest elephants are 5 hooves on the forelimb, and 4 to 5 on the hindlimb (Sikes 1971). Therefore, the number of hooves cannot be a diagnostic character of the species in this case. Concerning the ear shape, the character described above is rather that of the savanna elephants than that of the forest elephants (Grubb et al. 2000). In addition, concerning the body build of the African elephants, the back of the savanna elephants tend to be markedly concave, and that of the forest elephants tend to be nearly straight (Grubb et al. 2000; see also Fig. 1A and B). The back of Nana was relatively concave (Fig. 1C). In Japan, there were three forest elephants (e.g., JAZA 1991; Nana of the Asahiyama Zoo, Mari of the Tokuyama Zoo, and Bebe of the Okinawa Kids Discovery Kingdom), and all of them were identified as forest elephants mainly based on the body size and hoof structure (in the case of Bebe, the nearly linear back and rounded ears were also used). As we mentioned above, it