Isolation and pathogenic characterization of an OB1 variant of Babesia rodhaini which has a glycophorin A-independent pathway to murine red blood cells     

Noriyuki Takabatake  Hiroshi Iseki  Yuzuru Ikehara  Hirotaka Kanuka  Naoaki Yokoyama  Kazuhisa Sekimizu  Ikuo Igarashi 《Veterinary parasitology》2009

Recent studies using several Babesia spp. have demonstrated that these species commonly recognize host sialic acids of red blood cells (RBCs) for their invasion. Glycophorin A (GPA), which is a major carrier of the sialic acids on RBCs, is a possible invasive receptor for Babesia parasites. In the present study, a variant of Babesia rodhaini was successfully isolated from a GPA homozygous knockout (GPA^−/−) mouse infected with an Australian strain of B. rodhaini which had originally been unable to replicate in GPA^−/− mice. The isolated parasite (designated as an OB1 variant) caused lethal infection to wild-type mice, as in the case of the parent Australian strain. However, although the growth of the OB1 variant in GPA^−/− mice was comparable with that in wild-type mice at 1–4 days after infection, the growth was significantly inhibited from day 5 onward, leading to the eventual survival of the GPA^−/− mice. Resistance of GPA^−/− mice against OB1 infection was lost by splenectomy, although the cytokine responses to the infection in the sera of GPA^−/− mice were similar to those of wild-type mice. The autoantibody levels to GPA-defective RBCs in the sera of GPA^−/− mice were depressed at a lower level at 0–2 days after infection than those of wild-type mice, while the levels of GPA^−/− mice progressively increased and reached comparable levels to those of wild-type mice at day 3 or later. These results indicate that the isolated OB1 variant has a GPA-independent invasion pathway into murine RBCs and suggest that the resistance of GPA^−/− mice against infection with the OB1 variant may be attributed to the effective clearance of the parasitized RBCs lacking GPA in the spleen, possibly mediated by preferential autoantibody binding to the RBC membrane.  相似文献   

Cylindrocladium brown leaf spot on Howea belmoreana caused by Calonectria ilicicola (anamorph: Cylindrocladium parasiticum) in Japan     

Yuuri Hirooka  Jun Takeuchi  Hiromichi Horie  Keiko T. Natsuaki 《Journal of General Plant Pathology》2008,74(1):66-70

Brown leaf spot disease caused by Cylindrocladium was found on Howea belmoreana on Hachijojima Island, Tokyo, Japan, in December 2001. Typical symptoms were incited after artificial inoculation. A culture of white mycelia, isolated from leaf spot symptoms, produced reddish perithecia of a nectriaceous fungus. Based on morphological and molecular analyses, this fungus was identified as Calonectria ilicicola (anamorph: Cylindrocladium parasiticum). Pathogenicity of this fungus on five plants cultivated on Hachijojima Island was confirmed by artificial inoculation. This report is the first on Cylindrocladium brown leaf spot of H. belmoreana caused by C. ilicicola (anamorph: Cy. parasiticum).  相似文献   

Involvement of NbNOA1 in NO production and defense responses in INF1-treated Nicotiana benthamiana     

Hiroaki Kato  Shuta Asai  Ayako Yamamoto-Katou  Hirofumi Yoshioka  Noriyuki Doke  Kazuhito Kawakita 《Journal of General Plant Pathology》2008,74(1):15-23

During defense responses, plant cells produce nitric oxide (NO), which may control many physiological processes. In a previous study, we reported that nitrate reductase (NR) is responsible in part for INF1 elicitor-induced NO production in Nicotiana benthamiana, but the possibility remains that other NO-generating system(s) contribute to NO production. In mammalian cells, NO production is catalyzed by NO synthase (NOS). However, NOS-like enzyme(s) have never been identified in plants, and only the gene for Arabidopsis thaliana nitric oxide-associated 1 (AtNOA1) has been identified as a putative regulator of NOS activity in plants. In this study, we cloned NbNOA1, a homolog of AtNOA1, from N. benthamiana and investigated its involvement in NO production induced by INF1. The NbNOA1 gene was silenced by a virus-induced gene-silencing (VIGS) technique. NbNOA1-silenced plants had yellowish leaves. Silencing NbNOA1 partially decreased INF1-induced NO production, while overexpressing NbNOA1 did not affect NO production. Silencing NbNOA1 suppressed INF1-induced PR1a gene expression and increased susceptibility to Colletotrichum lagenarium. These results suggest that NbNOA1 is involved in INF1-mediated NO production and is required for defense responses. The nucleotide sequence data reported are available in the DDBJ/EMBL/GenBank databases under accession number AB303300.  相似文献   

Metabolite profiling of shoot extract,root extract,and root exudate of rice under nitrogen and phosphorus deficiency     

Keitaro Tawaraya  Ryota Horie  Tadao Wagatsuma  Kazuki Saito  Akira Oikawa 《Soil Science and Plant Nutrition》2018,64(3):312-322

ABSTRACT

Root exudate is derived from plant metabolites and its composition is affected by plant nutrient status. A deficiency of mineral nutrients, such as nitrogen (N) and phosphorus (P), strongly affects the type and amount of plant metabolites. We applied a metabolite profiling technique to investigate root exudates of rice plants under N and P deficiency. Oryza sativa was grown in culture solution containing two N levels (0 and 60 mg N L^?1) or two P levels (0 and 8 mg P L^?1). Shoot extracts, root extracts, and root exudates were obtained from the rice plants 5 and 15 days after transplanting and their metabolites were determined by capillary electrophoresis/time-of-flight mass spectrometry. Shoot N concentration and dry weight of rice plants grown at ?N level were lower than those of plants grown at +N level. Shoot P concentration and dry weight of rice plants grown at ?P level were lower than those of plants grown at +P level. One hundred and thirty-two, 127, and 98 metabolites were identified in shoot extracts, root extracts, and root exudates, respectively, at the two N levels. One hundred and thirty-two, 128, and 99 metabolites were identified in shoot extracts, root extracts, and root exudates, respectively, at the two P levels. Seventy-seven percent of the metabolites were exuded to the rhizosphere. The concentrations of betaine, gamma-aminobutyric acid, and glutarate in root exudates were higher at both ?N and ?P levels than at their respective high levels. The concentration of spermidine in root exudates was lower at both ?N and ?P levels than at their respective high levels. The concentrations of the other metabolites in root exudates were affected differently by plant N or P status. These results suggest that rice roots actively release many metabolites in response to N and P deficiency.  相似文献   

Detection of Pythium aphanidermatum in tomato using loop-mediated isothermal amplification (LAMP) with species-specific primers     

Shiro Fukuta  Reiko Takahashi  Satoru Kuroyanagi  Noriyuki Miyake  Hirofumi Nagai  Hirofumi Suzuki  Fujio Hashizume  Tomoko Tsuji  Hiromi Taguchi  Hideki Watanabe  Koji Kageyama 《European journal of plant pathology / European Foundation for Plant Pathology》2013,136(4):689-701

A loop-mediated isothermal amplification (LAMP) reaction with a primer set designed from the rDNA ITS sequence of P. aphanidermatum was developed. Results of a specificity test using 57 strains of Pythium spp. indicated that the LAMP assay gave no cross reactions in other 39 Pythium species, 11 strains of Phytophthora spp. and eight other soil borne pathogens. The detection limit was 10 fg of genomic DNA, which was ten times the sensitivity of the polymerase chain reaction. The LAMP assay was applied to hydroponic solution samples from tomato fields, and the results were compared to those of the conventional plating method. LAMP was observed to be effective for the specific detection of P. aphanidermatum. Furthermore, P. aphanidermatum was detected directly in tomato roots infected with P. aphanidermatum without DNA extraction. The LAMP method established in this study is a simple, sensitive and rapid tool for the detection of P. aphanidermatum.  相似文献   

合成气合成低碳醇热力学及试验研究     

袁浩然  陈新德  陈勇  马隆龙  小林敬幸  黄宏宇 《农业工程学报》2011,27(12):297-301

为了解决液体燃料缺乏以及农业废弃物处置的问题,该文分析了合成低碳醇的重要性,提供了一条解决农业废弃物的方法,并通过热力学分析指导低碳醇的合成.文中使用平衡常数法对合成气合成低碳醇进行热力学分析计算,并验证了计算结果符合理论分析的趋势,得到降低温度、提高压力有利于CO的转化和醇类的生成,以及不同H2/CO摩尔比的情况下C...  相似文献   

Epigenetic assessment of environmental chemicals detected in maternal peripheral and cord blood samples     

Arai Y  Ohgane J  Yagi S  Ito R  Iwasaki Y  Saito K  Akutsu K  Takatori S  Ishii R  Hayashi R  Izumi S  Sugino N  Kondo F  Horie M  Nakazawa H  Makino T  Shiota K 《The Journal of reproduction and development》2011,57(4):507-517

Epigenetic alteration is an emerging paradigm underlying the long-term effects of chemicals on gene functions. Various chemicals, including organophosphate insecticides and heavy metals, have been detected in the human fetal environment. Epigenetics by DNA methylation and histone modifications, through dynamic chromatin remodeling, is a mechanism for genome stability and gene functions. To investigate whether such environmental chemicals may cause epigenetic alterations, we studied the effects of selected chemicals on morphological changes in heterochromatin and DNA methylation status in mouse ES cells (ESCs). Twenty-five chemicals, including organophosphate insecticides, heavy metals and their metabolites, were assessed for their effect on the epigenetic status of mouse ESCs by monitoring heterochromatin stained with 4￠,6-diamino-2-phenylindole (DAPI). The cells were surveyed after 48 or 96 h of exposure to the chemicals at the serum concentrations of cord blood. The candidates for epigenetic mutagens were examined for the effect on DNA methylation at genic regions. Of the 25 chemicals, five chemicals (diethyl phosphate (DEP), mercury (Hg), cotinine, selenium (Se) and octachlorodipropyl ether (S-421)) caused alterations in nuclear staining, suggesting that they affected heterochromatin conditions. Hg and Se caused aberrant DNA methylation at gene loci. Furthermore, DEP at 0.1 ppb caused irreversible heterochromatin changes in ESCs, and DEP-, Hg- and S-421-exposed cells also exhibited impaired formation of the embryoid body (EB), which is an in vitro model for early embryos. We established a system for assessment of epigenetic mutagens. We identified environmental chemicals that could have effects on the human fetus epigenetic status.  相似文献   

Effects of Cd on the fluxes of K+ and H+ in excised roots     

Hitoshi Obata  Noriyuki Inoue  Motoaki Matsuoka  Masanao Umebayashi 《Soil Science and Plant Nutrition》2013,59(2):439-442

As a result of Cd treatment, K concentrations decreased in Cd sensItive maize and kidney bean calli (Obata et al. 1994) and in intact roots of kidney bean plants (Obata et al. unpublished). Potassium may be extruded from the roots or the absorption of K may be depressed by the Cd treatment in these Cd sensitive plants. Obata et al. (1996) observed that Cd inhibited both the efflux of H⁺ and influx of K⁺ following K⁺ addition in intact roots of bean. Thus Cd may affect the activity of proteins essential to ion movement., i.e. ioncarriers, channels and ATPase embedded in the membranes and/or may affect the permeability of the lipids of the membrane.  相似文献   

Genomic organization of the porcine dopachrome tautomerase (DCT) gene     

Naohiko OKUMURA  Noriyuki HAMASIMA  Kohei SUZUKI  Takashi AWATA 《Animal Science Journal》2008,79(2):182-186

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Evaluation of duodenal perfusion by contrast‐enhanced ultrasonography in dogs with chronic inflammatory enteropathy and intestinal lymphoma     

Khoirun Nisa  Sue Yee Lim  Masayoshi Shinohara  Tatsuyuki Osuga  Nozomu Yokoyama  Masahiro Tamura  Noriyuki Nagata  Kazuyoshi Sasaoka  Angkhana Dermlim  Rommaneeya Leela‐Arporn  Tomoya Morita  Noboru Sasaki  Keitaro Morishita  Kensuke Nakamura  Hiroshi Ohta  Mitsuyoshi Takiguchi 《Journal of veterinary internal medicine / American College of Veterinary Internal Medicine》2019,33(2):559-568

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