An avirulence gene homologue in the tomato wilt fungus Fusarium oxysporum f. sp. lycopersici race 1 functions as a virulence gene in the cabbage yellows fungus F. oxysporum f. sp. conglutinans     

Takeshi Kashiwa  Keigo Inami  Masashi Fujinaga  Hideki Ogiso  Takanobu Yoshida  Tohru Teraoka  Tsutomu Arie 《Journal of General Plant Pathology》2013,79(6):412-421

Six4, a small protein secreted by Fusarium oxysporum f. sp. lycopersici (Fol) in tomato xylem sap during infection, triggers Fol race 1-specific resistance (I) in tomato. SIX4 is regarded as an avirulence gene. Although SIX4 is considered unique to Fol race 1, we detected this gene in the cabbage yellows fungus F. oxysporum f. sp. conglutinans (Foc) by PCR. Because the genes from Foc and SIX4 in Fol were >99 % identical at the nucleotide level, the Foc gene was designated FocSIX4. The expression of FocSIX4 was detected by RT-PCR in stems and roots of cabbage 8 days after infection with Foc. In contrast with Fol, disruption of FocSIX4 in Foc did not increase virulence to Foc-resistant cabbage cvs. Shutoku-SP and Koikaze. On the contrary, the disruptants had reduced virulence not only on Foc-resistant cultivars but also on Foc-susceptible cv. Shikidori. These results suggested that FocSIX4 is involved in virulence, but not in avirulence, in the cabbage yellows fungus.  相似文献   

Construction of a system for exploring mitotic homologous recombination in the genome of Pyricularia oryzae     

Takayuki Arazoe  Shuichi Ohsato  Tsutomu Arie  Katsuyoshi Yoneyama  Shigeru Kuwata 《Journal of General Plant Pathology》2013,79(6):422-430

To investigate mitotic homologous recombination (HR) in Pyricularia oryzae, we created an HR detection system. The system consists of two non-functional enhanced yellow fluorescent protein (YFP) and blasticidin S deaminase (BSD) fusion genes (YFP::BSD). If mitotic HR occurs between the two non-functional genes in the genome, restoration of the functional YFP::BSD gene can be expected. The expression of the functional YFP::BSD gene can be detected by both YFP fluorescence and resistance against BS. When the P. oryzae genome was transformed simultaneously with two non-functional genes, all six lines of transformants with both genes had some portion of their hyphae exhibiting YFP fluorescence and BS resistance during growth. Up to ca. 10 % of conidia harvested from the mycelium of each of the six lines had YFP fluorescence, suggesting that HR consistently occurs during mycelium growth. To determine whether and how the HR-mediated phenotypic changes occurred at the DNA level, we analyzed the genomic DNA of BS-resistant mycelia by PCR-RFLP and sequencing and were able to confirm the existence of a restored functional YFP::BSD gene and a non-functional recombinant gene. Collectively, these findings demonstrate that we established a successful HR detection system for P. oryzae, which can be used for other plant pathogens, and that mitotic HR actually occurs in P. oryzae and constitute the first experimental evidence for mitotic HR in a fungus.  相似文献   

Antimicrobial susceptibilities of Listeria monocytogenes isolated in Japan     

Okada Y  Okutani A  Suzuki H  Asakura H  Monden S  Nakama A  Maruyama T  Igimi S 《The Journal of veterinary medical science / the Japanese Society of Veterinary Science》2011,73(12):1681-1684

The antimicrobial susceptibility of 201 Listeria monocytogenes isolates from foods, environments, animals and human patients in Japan was determined. All isolates were susceptible to ampicillin, the first choice of drug for listeriosis treatment, chloramphenicol, dihydrostreptomycin, erythromycin, enrofloxacin, gentamicin, kanamycin, lincomycin, nosiheptide, salinomycin, vancomycin, and virginiamycin. A human strain was resistant to oxytetracycline. The Minimum Inhibitory Concentration (MIC) for 50% of the strains and the MIC for 90% of the strains were comparable in all the isolates. This is the first investigation to compare antibiotic resistances between isolates from foods and isolates from human patients in Japan. The result showed that most of the isolates were susceptible to antibiotics used in this study.  相似文献   

Basal levels and GnRH-induced responses of peripheral testosterone and estrogen in Holstein bulls with poor semen quality     

Devkota B  Takahashi K  Matsuzaki S  Matsui M  Miyamoto A  Yamagishi N  Osawa T  Hashizume T  Izaike Y  Miyake Y 《The Journal of reproduction and development》2011,57(3):373-378

The present study investigated the basal levels and GnRH-induced responses of peripheral testosterone and estrogen in Holstein bulls with poor semen quality. On the basis of semen parameters, bulls (n=5) having poor semen quality were selected as experimental bulls, and good semen quality bulls (n=4) were used as control bulls. Both groups were treated intramuscularly once with GnRH (250 μg of fertirelin acetate). Blood samples were collected at -1 day (d), -30 min and 0 h (treatment) followed by every 30 min for 5 h and 1, 3 and 5 d post-GnRH treatment (PGT), and LH, testosterone and estradiol-17β (E(2)) concentrations were measured. The pretreatment concentrations were used as basal levels. The percentage increments based on the 0-h levels were calculated per bull for each sampling time until 5 h PGT, and differences were compared between the experimental and control groups. The PGT concentrations of testosterone and basal and PGT concentrations of E(2) were significantly lower in the experimental group. The testosterone increment in the experimental group was delayed and significantly lower from 1 to 5 h PGT than those in the control group. It can be suggested that bulls with poor semen quality have delayed and lower GnRH-induced testosterone response and may also have lower estrogen levels.  相似文献   

DNA methylation status of bovine blastocyst embryos obtained from various procedures     

Sawai K  Takahashi M  Fujii T  Moriyasu S  Hirayama H  Minamihashi A  Hashizume T  Onoe S 《The Journal of reproduction and development》2011,57(2):236-241

DNA methylation is an important factor for the regulation of gene expression in early embryos. It is well known that the satellite I sequence is more heavily methylated in bovine somatic cell nuclear transfer (NT-SC) embryos than in embryos derived from in vitro fertilization (IVF). However, the methylation status of bovine embryos obtained by other procedures is not well known. To clarify DNA methylation levels of bovine embryos obtained from various procedures, we examined satellite I sequences in bovine blastocyst (BC) embryos derived from NT-SC, NT using embryonic blastomeres (NT-EM), in vivo (Vivo), IVF and parthenogenetic treatment (PA). Furthermore, in order to evaluate the efficacy of DNA demethylation by the NT procedure, we determined the DNA methylation levels in bovine embryos in which NT was recapitulated (Re-NT). Although the DNA methylation levels in the NT-SC embryos were higher than those in the other embryos, the NT-EM embryos exhibited lower DNA methylation levels. The satellite I sequence in the NT-SC embryos was more demethylated than that in the donor cells. Although the DNA methylation level in the individual NT-SC embryos showed variation, the full-term developmental efficacy of these embryos were not different. These findings suggest that the methylation level of the satellite I sequence at the BC stage is not related to the abnormalities of bovine embryos produced by NT-SC. There was no difference in methylation levels between Re-NT and NT-SC embryos. Our results indicated that the DNA methylation status differed among embryos produced by various methods and that at least some of the demethylation of the donor cell genome occurred in the recipient cytoplast after NT-SC, but the demethylation ability of the NT procedure was noted in the first NT but not in the second NT.  相似文献   

Length of Incubation for the Estimation of the Most Probable Number of Nitrifying Bacteria in Soil     

Tomoyoshi Hashimoto  Tsutomu Hattori 《Soil Science and Plant Nutrition》2013,59(3):507-509

Abstract

The Zn content in 8 soil chemical fractions was determined for 21 greenhouse soils and for 8 reference (open field) soils from Kochi Prefecture, Japan to investigate the forms of spontaneously accumulated Zn in the greenhouse soils associated with heavy application of fertilizers and manures. Sequential extraction method was applied to every soil and each Zn fraction was designated as exchangeable (Ex-Zn), Pb-displaceable (Pb-Zn), acid soluble (Aci-Zn), Mn oxide-occluded (MnO-Zn), organically bound (OM-Zn), amorphous Fe oxide-occluded (AFeO-Zn), crystalline Fe oxide-occluded (CFeO-Zn), and residual (Res-Zn) fractions. The Zn content of the greenhouse soils was significantly higher than that of the reference soils in every fraction, except for the CFeO-Zn, and Res-Zn fractions. The Pb-Zn, Aci-Zn, and MnO-Zn fractions showed a difference of more than 60% in the total Zn content between the two soil groups. The amounts of Zn extracted in the Pb-Zn, Aci-Zn, MnO-Zn, AFeO-Zn, and CFeO-Zn fractions of the greenhouse soils increased con-comitantly with the accumulation of applied macro-nutrients. These results indicated that the accumulation of Zn in greenhouse soils caused by intensive fertilization had proceeded through specific adsorption onto or occlusion by the oxides and hydroxides of Fe and Mn in soils.  相似文献   

Influence of phosphate sorption on dispersion of a Ferralsol     

Dung Viet Pham  Munehide Ishiguro  Ha Thu Thi Tran  Tsutomu Sato 《Soil Science and Plant Nutrition》2013,59(3):356-366

Abstract

Soil dispersion induces soil erosion and colloidal leaching. Nutrients are lost at the same time and this causes water contamination. Phosphate is an essential element for living organisms. Because phosphate influences soil dispersion and it is an important limited resource, this influence must be evaluated well in order to diminish negative effects on soil structure. In this paper, we firstly evaluated the influence of phosphate sorption on soil dispersion by calculating repulsive potential energy between soil particles. Ferralsol, which is a typical soil in rainy tropical regions, was used as the material. The dispersion-flocculation phenomena were investigated with absorbance of soil suspension under different pH, phosphate adsorption and electrolyte concentration in an Na-NO₃-PO₄ system. The repulsive potential energy was calculated based on the diffuse double layer theory and the measured zeta potential. We indicated that the measured absorbance increased with the increase of the repulsive potential energy. The repulsive potential energy increased with increasing phosphate sorption up to about 5 to 20 mmol kg^?1 at all pH, and it induced the soil dispersion, because phosphate sorption increased the negative charge of the soil. After its peak, it decreased with increasing phosphate sorption because the electrolyte concentration increased and the electrolyte screened the electric field near the soil surface. The repulsive potential energy also increased with increasing pH because of the increase of the negative charge of the soil. Even at low pH, after a certain amount of phosphate sorption, the soil dispersed due to the increase of repulsive potential energy, although the soil flocculated before phosphate application. Because the soil dispersion causes soil and phosphorus loss, the influence of soil pH and phosphate sorption on the soil dispersion should be considered for good soil management.  相似文献   

Bacteriological studies on the mineralization of soil organic nitrogen in paddy soils     

Koichiro Hiura  Kyo Sato  Tsutomu Hattori  Choseki Furusaka 《Soil Science and Plant Nutrition》2013,59(2):201-205

Anaerobes were isolated from both disrupted and undisrupted soil samples incubated under submerged condition. All isolates were divided into 9 groups based on their gram stain and morphological characteristics. Correlation coefficients between the amount of nitrogen mineralized and the number of each group were calculated. A significant correlation was observed only between the amount of nitrogen mineralized and the number of gram positive-rod shaped anaerobic microorganisms (r=0.768 at P=0.05). This result indicates that in this study system, sorne particular anaerobes may play an important role in the mineralization of soil organic nitrogen.  相似文献   

Bacteriological studies on the mineralization of organic nitrogen in paddy soils     

Koichiro Hiura  Tsutomu Hattori  Choseki Furusaka 《Soil Science and Plant Nutrition》2013,59(4):459-465

In this report we studied the effects of mechanical grinding of paddy soils on nitrogen mineralization and bacterial number when soils were incubated under a submerged condition after grinding.

Nitrogen mineralization was increased by grinding soil samples as compared with those without grinding. The value of (Nd-Nu)/Nu, where Nd is the amount of ammonia-nitrogen formed by incubation of disrupted samples and Nu those of the undisrupted soils, was in good correlation with clay/humus ratio.

Although significant difference was not observed between the number of aerobic bacteria with undisrupted and disrupted soil samples, higher anaerobic bacterial numbers were found with disrupted than with undisrupted ones.

A significant correlation was also obtained between the amounts of nitrogen mineralization increased by the grinding of soil and the numbers of anaerobic bacteria.  相似文献   

Effects of topography and planted trees on the distribution of naturally regenerated broad-leaved trees in a 140-year-old <Emphasis Type="Italic">Cryptomeria japonica</Emphasis> plantation in northern Kyushu,Japan     

Takafumi Inoue  Tsutomu Enoki  Naoaki Tashiro  Kotaro Sakuta  Susumu Inoue 《Journal of Forest Research》2008,13(6):365-371

We investigated factors affecting the distribution of naturally regenerated broad-leaved trees in a 140-year-old Cryptomeria japonica plantation. We used path analysis to examine the relationship among microtopography, the biomass of planted trees, and the biomasses of canopy and subcanopy trees of broad-leaved species. The study plot was divided into three topographic types (ridge, slope, and valley), and we discuss how the different topographic types are affected. For all topographic types, the biomass of canopy trees of broad-leaved species decreased with convexity. For slope and valley topographies, the biomass of subcanopy trees of broad-leaved species also decreased with convexity. For ridge topography, the biomass of subcanopy trees of broad-leaved species increased with the biomass of planted trees, and decreased with the biomass of canopy trees of broad-leaved species. These results suggest the effects of microtopography on the biomass of subcanopy trees were much larger than the effects of canopy trees for slope and valley topographies, while the effects of microtopography were smaller for ridge topography.  相似文献