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A Seroepidemiological Survey of Theileria equi and Babesia caballi in Horses in Mongolia
Get PDFapplication/pdfEquine piroplasmosis caused by Theileria equi and Babesia caballi is an economically important disease with a worldwide distribution. The objective of the present study was to investigate the seroepidemiology of T. equi and B. caballi in horses reared in various Mongolian provinces. Serum samples prepared from blood collected from horses in 19 Mongolian provinces were screened for antibodies specific to T. equi and B. caballi using enzyme-linked immunosorbent assays based on recombinant forms of T. equi merozoite antigen-2 and the B. caballi 48-kDa merozoite rhoptry protein, respectively. Of 1,282 horses analyzed, 423 (33%) and 182 (14.2%) were sero-positive for T. equi and B. caballi, respectively. Additionally, 518 (40.4%) were positive for at least 1 parasite species, of which 87 (16.8%) were co-infected with both parasites. Both T. equi and B. caballi were detected in all surveyed provinces, and on a per province basis the positive rates ranged from 19.0 to 74.2% and 4.5 to 39.8%, respectively. Theileria equi- and B. caballi-positive rates were comparable between male horses (31.9 and 14.1%, respectively) and female horses (34.5 and 14.3%, respectively). However, the positive rates were higher in the >3-yr-old age group (37.7 and 15.6%, respectively) compared with the 1-3-yr-old age group (19.4 and 10.0%, respectively). These findings confirmed that T. equi and B. caballi infections are widespread among horses all over Mongolia, and that horse age is a risk factor for infection in this country. Our results will be useful for designing appropriate control measures to minimize T. equi and B. caballi infections among Mongolian horses.journal articl
1世代でかなりの遺伝的改良効果が期待できる：乳成分と乳量は負の関係にあることに注意を
Get PDFapplication/pdf乳成分率と乳量はマイナスの相関関係があるため、乳成分率を大きく改良する種雄牛の多くは乳量の改良が期待できない。しかし、乳成分率は1世代でかなりの改良成果が期待できるため、乳成分率の遺伝的改良に取り組む意義は大きい。journal articl
北海道東部における天然生落葉広葉樹林の樹洞資源の特徴 : エゾモモンガの樹洞資源利用可能性に着目して
Get PDFapplication/pdf樹洞に営巣する鳥類や哺乳類（以下、樹洞営巣動物）にとって、樹洞は有限かつ生活に不可欠な資源であり、樹洞の数（以下、樹洞量）はその生息地の質を反映する指標の一つである。よって、樹洞木の特徴を理解し、その地域の樹洞量を把握することは樹洞営巣動物の生態を明らかにする上で重要である。北海道にはユーラシア大陸北部一帯に生息するタイリクモモンガPteromysvolans の一亜種であるエゾモモンガP. volans orii が生息しており、樹洞を主な営巣資源として用いることが知られているが、樹洞量がその生息地選択に与える影響については不明である。本亜種はユーラシア個体群とは異なり、樹洞が形成されやすい落葉広葉樹のみで構成される森林にも生息するため、広葉樹林における豊富な樹洞量が本種に与える影響を評価する上で恰好の研究対象である。そこで本研究では、北海道東部の天然生落葉広葉樹林に存在するエゾモモンガの営巣木となり得る樹洞木の特徴と樹洞量を異なる森林植生間で比較検討し、本種の営巣資源に関する基礎生態学的な情報を提示することを目的とした。その結果、イタヤカエデAcer mono が多い広葉樹林はミズナラQuercus crispula が多い広葉樹林と比較して約1.8 倍もの樹洞量を有し、これは樹種構成に起因する樹木成長率や樹洞発生率、生立木の本数の違いが反映されたためであると考えられた。また、植生に関わらず樹洞を有する樹木は樹洞が存在しない樹木よりも樹高が低い傾向が示されたが、これは、低樹高の樹木では光抑制ストレスの蓄積により樹幹が脆弱化し、腐朽が生じ易くなったためであると考えられるかもしれない。Tree cavities are important and limited resources for arboreal small-sized mammals and forest birds. Therefore,cavities may be useful indicators for evaluating habitat quality. To understand ecological characteristics of animals nesting in cavities, it is important to understand characteristics of cavity trees and document number of cavities in the habitat. The Siberian flying squirrel, Pteromys volans, is widely distributed in the northern part of Eurasian Continent,Sakhalin, and Hokkaido; is arboreal; and nests in cavities.On Hokkaido Island, Japan, there is an endemic subspecies,Pteromys volans orii. Unlike the Eurasian population's habitat (coniferous or mixed forest), the Hokkaido population occurs in deciduous or mixed forest. In general, deciduous trees have more cavities than coniferous trees. On Hokkaido,then, deciduous forests may provide more nest resources for Siberian flying squirrels. To obtain fundamental information on cavity resources in Hokkaido’s deciduous forests, we documented number of cavities and characteristics of cavity trees in two different deciduous forests: Acer mono-rich forest and Quercus crispula-rich forest. The Acer mono-rich forest had many more cavities that the Quercus crispula-rich forest.Tree growth rate, number of cavities, and number of live trees may have affected this difference. In both forests, more cavities were found in shorter sub-canopy trees than in taller canopy trees. These sub-canopy trees may be more likely to decay because of the stress of competing for sunlight.departmental bulletin pape
EFL Motivation and Possible Selves: A Comparison of Technical College and University Students in Japan
Get PDFapplication/pdfDespite needing English for their professional careers, Japanese students majoring in science,technology, engineering, and mathematics (STEM) experience problems with language learning motivation. Building on previous studies indicating demotivation among such students, this paper presents results from a large-scale study of English as a Foreign Language (EFL) students in STEM programs in technical high schools and universities. Using a questionnaire of 48 Likert-type items measuring nine motivational, psychological, and social factors, including anxiety, perceived classroom atmosphere,international friendship, and Possible L2 Selves (N = 2,253), data were fit to an existing structural equation model and MANOVA was conducted to compare the two groups. Findings indicated that the Ideal L2 Self was not as pertinent as the Ought-to L2 Self for both groups of students. While both groups had a strong sense of the value of English for careers, technical college students had a lower sense of a supportive classroom atmosphere, less interest in English-speaking cultures, and a weaker sense of an ideal self. Results demonstrated the influence of the social context both inside and outside the classroom environment, while also suggesting that improving classroom group dynamics and activities may encourage a stronger sense of supportive class structures and perceived competence.departmental bulletin pape
Sexual introgression of the late blight resistance gene Rpi-blb3 from a Mexican wild diploid species Solanum pinnatisectum Dunal into potato varieties
Get PDFapplication/pdfSolanum pinnatisectum Dunal (2n = 2x = 24) is a tuber-bearing Mexican wild species that has an extremely high level of resistance to late blight (Phytophthora infestans). However, this species is distantly related and isolated from cultivated potato species by a strict sexual reproduction barrier. Previously, we successfully obtained triploid interspecific hybrids between chromosome-doubled S. pinnatisectum and a South American diploid clone carrying the S locus inhibitor gene (Sli). In this study, chromosome doubling of triploid hybrids was done to produce hexaploids used as the recurrent and donor parents in the successive backcrossing scheme. In a BC2 population consisting of 198 genotypes, P. infestans was inoculated. Ninety-six genotypes were resistant, and 102 were susceptible. The presence of the Rpi-blb3–specific marker band perfectly matched the resistance phenotype, verifying that the Rpi-blb3 gene controlled resistance. BC1 and BC2 progenies were relatively easy to reciprocally cross with cultivars. Therefore, the Rpi-blb3 gene derived from S. pinnatisectum could be used in practical breeding to confer a high level of late blight resistance to potato varieties with the aid of the gene-specific marker. © 2019, Springer Nature B.V.journal articl
Intracellular localization of vitellogenin receptor mRNA and protein during oogenesis of a parthenogenetic tick, Haemaphysalis longicornis
Get PDFapplication/pdfBACKGROUND: Vitellogenin (Vg), a key molecule for oocyte development synthesized in the fat body during blood-feeding, is released into the hemolymph and then taken into the oocytes via Vg receptor (VgR) in ticks. Previously, we showed that VgR mRNA is expressed in the ovary at the adult stage of parthenogenetic Haemaphysalis longicornis ticks and its expression increases after blood-feeding. However, intracellular localization of VgR mRNA and protein at each developmental stage of oocytes during oogenesis remains largely unclear. METHODS: mRNA and protein expression profiles of H. longicornis VgR (HlVgR) in the oocytes from the unfed to oviposition periods were analyzed by real-time PCR, in situ hybridization, and immunostaining. To elucidate the timing of the onset of Vg uptake, RNA interference (RNAi)-mediated gene silencing of HlVgR was performed. RESULTS: In situ hybridization revealed that HlVgR mRNA was detected in the cytoplasm of stage I-III oocytes, and weaker positive signals for HlVgR mRNA were found in the cell periphery of stage IV and V oocytes. Likewise, HlVgR protein was detected by immunostaining in the cytoplasm of stage I-III oocytes and in the cell periphery of stage IV and V oocytes. Each developmental stage of the oocytes showed distinct patterns of mRNA and protein expression of HlVgR. Moreover, RNAi of HlVgR caused delayed or arrested development in the oocytes. The ovaries of control ticks showed all developmental stages of oocytes, whereas stage I-III oocytes were found in the ovaries of HlVgR-RNAi ticks at 5 days after engorgement. CONCLUSIONS: These results suggest that active uptake of Vg is required for development from stage III to stage IV during oogenesis. Our data clearly revealed an apparent shift in the intracellular localization of VgR for both mRNA and protein level in oocytes during oogenesis.journal articl
Length of lags in responses of milk yield and somatic cell score on test day to heat stress in Holsteins
Get PDFapplication/pdfWe used daily records from provincial Japanese weather stations and monthly test-day records of milk production to investigate the length of the lags in the responses of cows’ milk yield and somatic cell score (SCS) to heat stress (HS). We also investigated the HS thresholds in milk yield and SCS. Data were a total of 17,245,709 test-day records for milk and SCS in Holstein cows that had calved for the first time between 2000 and 2015, along with weather records from 60 weather stations. Temperature–humidity index (THI) values were estimated by using average daily temperature and average daily relative humidity. Adjusted THI values were calculated by using temperature, relative humidity, wind speed, and solar radiation. The model contained herd, calving year, month of test day, age group, days in milk, and THI as a fixed effect. THIs for each day from 14 days before the test day until the test day were used to represent the HS effects. The HS occurring 3 days, and between 8 and 10 days, before the test day had the greatest effect on the milk yield and SCS, respectively. The threshold THI values for the HS effect were about 60–65 for both traits. © 2019 The Authors. Animal Science Journal published by John Wiley & Sons Australia, Ltd on behalf of Japanese Society of Animal Sciencejournal articl
Molecular screening approach to identify protozoan and trichostrongylid parasites infecting one-humped camels (Camelus dromedarius)
Get PDFapplication/pdfLittle is known about the diversity of many parasites infecting camels, with most relying on morphological parameters. DNA extracted from different tissues (n = 90) and fecal samples (n = 101) from dromedary camels (Camelus dromedarius) in Egypt were screened for multiple parasites using different molecular markers. Screening of tissue samples (heart) for Toxoplasma gondii and Sarcocystis spp. was performed using B1 and 18S rRNA gene markers, respectively. T. gondii was further genotyped using multiplex multilocus nested PCR-RFLP (Mn-PCR-RFLP). Sarcocystis was analyzed using PCR-RFLP characterization (XbaI and MboI restriction enzymes). A taxonomically challenging but important group of nematodes (Trichostrongylidae family) were screened using the ITS-2 ribosomal DNA (rDNA) species-specific markers. Furthermore, nested PCR was used for the detection of Cryptosporidium spp. (SSU rRNA gene) and positive samples were genotyped after RFLP (SspI and VspI) and sequencing. Cryptosporidium parvum isolates were subtyped by sequence analysis of the 60-kDa glycoprotein gene. This study revealed that many parasites infect the investigated camels, including T. gondii (1.1%), Sarcocystis spp. (64.4%), Cryptosporidium spp. (5.9%) and Trichostrongylidae nematodes (22.7%). The species contribution for nematodes was as follows: Haemonchus spp. (95.6%), Trichostrongylus axei (26%), Trichostrongylus colubriformis (65.2%) and Cooperia oncophora (60.8%). Mn-PCR-RFLP typing for Toxoplasma was only successful for three markers: 5′-SAG2 (type II), 3′-SAG2 (type II) and alt. SAG2 (type II). PCR-RFLP using XbaI showed possible mixed Sarcocystis infection. Moreover, the Cryptosporidium genotypes detected were C. parvum (IIdA19G1 and IIaA15G1R1), Cryptosporidium rat genotype IV and a novel genotype (camel genotype). This approach revealed the unique Cryptosporidium genotypes infecting the investigated camels, and the high genetic diversity of the investigated parasites. © 2019 Elsevier B.V.journal articl
Evaluation of the inhibitory effect of ivermectin on the growth of Babesia and Theileria parasites in vitro and in vivo
Get PDFapplication/pdfBackground: Treatment is the principle way to control and eliminate piroplasmosis. The search for new chemotherapy against Babesia and Theileria has become increasingly urgent due to parasite resistance to current drugs. Ivermectin (IVM) was the world's first endectocide, capable of killing a wide variety of parasites and vectors, both inside and outside the body. It is currently authorized to treat onchocerciasis, lymphatic filariasis, strongyloidiasis, and scabies. The current study documented the efficacy of IVM on the growth of Babesia and Theileria in vitro and in vivo. Methods: The fluorescence-based assay was used for evaluating the inhibitory effect of IVM on four Babesia species, including B. bovis, B. bigemina, B. divergens, B. caballi, and Theileria equi, the combination with diminazene aceturate (DA), clofazimine (CF), and atovaquone (AQ) on in vitro cultures, and on the multiplication of a B. microti-infected mouse model. The cytotoxicity of compounds was tested on Madin-Darby bovine kidney (MDBK), mouse embryonic fibroblast (NIH/3 T3), and human foreskin fibroblast (HFF) cell lines. Results: The half-maximal inhibitory concentration (IC50) values determined for IVM against B. bovis, B. bigemina, B. divergens, B. caballi, and T. equi were 53.3 ± 4.8, 98.6 ± 5.7, 30.1 ± 2.2, 43.7 ± 3.7, and 90.1 ± 8.1 μM, respectively. Toxicity assays on MDBK, NIH/3 T3, and HFF cell lines showed that IVM affected the viability of cells with a half-maximal effective concentration (EC50) of 138.9 ± 4.9, 283.8 ± 3.6, and 287.5 ± 7.6 μM, respectively. In the in vivo experiment, IVM, when administered intraperitoneally at 4 mg/kg, significantly (p < 0.05) inhibited the growth of B. microti in mice by 63%. Furthermore, combination therapies of IVM-DA, IVM-AQ, and IVM-CF at a half dose reduced the peak parasitemia of B. microti by 83.7%, 76.5%, and 74.4%, respectively. Moreover, this study confirmed the absence of B. microti DNA in groups treated with combination chemotherapy of IVM + DA and IVM + AQ 49 days after infection. Conclusions: These findings suggest that IVM has the potential to be an alternative remedy for treating piroplasmosis. © 2019 The Author(s).journal articl