The mechanism of bentazon selectivity     

Akihiko Mine  Masakazu Miyakado  Shooichi Matsunaka 《Pesticide biochemistry and physiology》1975,5(6):566-574

Absorption, translocation and metabolism of [¹⁴C]3-isopropyl-2,1,3-benzothiadiazin-4-one-2,2-dioxide (bentazon) by several plant species were investigated to determine the mechanism of bentazon selectivity.Marked selective phytotoxicities were observed between resistant rice (Oryza sativa L.) and susceptible Cyperus serotinus Rottb. when treated with bentazon. Absorption and transolcation of bentazon did not differ greatly between highly resistant rice and susceptible C. serotinus. However, a marked difference in bentazon metabolism occurred between the two species. In rice about 80% of the absorbed bentazon was metabolized within 24 h, and after 7 days about 85% was converted to a major water-soluble metabolite and unchanged bentazon was only 5%. In C. serotinus 50–75% of the radioactivity was unchanged bentazon after 7 days.Large amounts of water-soluble metabolites were detected in root-treated resistant plants such as barnyardgrass (Echinochloa crus-galli Beauv.), soybean (Glycine max Merr.) and corn (Zea mays L.), but only small amounts were present in such susceptible plants as Sagittaria pygmaea Miq. and Eleocharis kuroguwai Ohwi. Therefore, the mechanism of bentazon selectivity appears to be a difference between resistant and susceptible species in their ability to metabolize and detoxify bentazon.The major metabolite in rice was identified as 6-(3-isopropyl-2,1,3-benzothiadiazin-4-one-2,2-dioxide)-O-β-glucopyranoside, determined by GC-MS, NMR, IR and gas chromatography after hydrolysis with sulfuric acid or β-glucosidase.  相似文献   

Polyphosphate kinase is essential for swarming motility, tolerance to environmental stresses, and virulence in Pseudomonas syringae pv. tabaci 6605     

Md. Mijan Hossain  Chiharu Tani  Tomoko Suzuki  Fumiko Taguchi  Tatsuhiro Ezawa  Yuki Ichinose   《Physiological and Molecular Plant Pathology》2008,72(4-6):122-127

Polyphosphate kinase (PPK), encoded by the ppk gene, is a principal enzyme responsible for synthesis of inorganic polyphosphate (poly P) from ATP in many Gram-negative bacteria. In order to elucidate the functions of poly P in Pseudomonas syringae pv. tabaci 6605, an in-frame deletion mutant of the ppk gene (ppk) was constructed. The ppk mutant did not accumulate poly P, whereas the wild-type strain accumulated a large quantity. The mutant had reduced swarming motility, even though it retains swimming motility like the parental strain. The mutant exhibited increased sensitivity to prolonged incubation and environmental stresses, such as heat shock and oxidative stress and reduced exopolysaccharide (EPS) production compared to the wild-type. Northern blot analysis revealed that expression of the rpoS gene, encoding the stationary phase sigma factor RpoS, was reduced in ppk in the logarithmic phase, indicating that rpoS is regulated by the ppk gene. The poly P deficient mutant had significantly reduced ability to cause disease in its host tobacco plant and in planta growth of the mutant was also significantly reduced in host tobacco leaves as compared to the wild-type strain. Thus, our results suggest that poly P plays an important role in the virulence of P. syringae pv. tabaci 6605.  相似文献   

Taxonomic characterization of Pyricularia isolates from green foxtail and giant foxtail, wild foxtails in Japan   总被引：1，自引：0，他引：1  

Akiko Yamagashira  Chihiro Iwai  Masakazu Misaka  Kenji Hirata  Yoshikatsu Fujita  Yukio Tosa  Motoaki Kusaba 《Journal of General Plant Pathology》2008,74(3):230-241

Twenty-eight Pyricularia isolates from two wild foxtails—green foxtail (Setaria viridis) and giant foxtail (S. faberii)—in Japan were taxonomically characterized by DNA analyses, mating tests, and pathogenicity assays. Although most of the isolates failed to produce perithecia in mating tests with Magnaporthe oryzae, a diagnostic polymerase chain reaction-restriction fragment length polymorphism phenotype of M. oryzae was detected in the beta-tubulin genomic region in all isolates. The pathogenicity assays revealed that host ranges of the isolates were similar to those of isolates from foxtail millet (S. italica), which were exclusively pathogenic on foxtail millet. In addition to the 28 isolates from wild foxtails, 22 Pyricularia isolates from 11 other grasses were analyzed by RFLP using single-copy sequences as probes. In a dendrogram constructed from the RFLP data, isolates that were previously identified as M. oryzae formed a single cluster. All the wild foxtail isolates formed a subcluster with foxtail millet isolates within the M. oryzae cluster. From these results, we conclude that Pyricularia isolates from the wild foxtails are closely related to isolates from foxtail millet and should be classified into the Setaria pathotype of M. oryzae.  相似文献   

Inhibitory effects of <Emphasis Type="SmallCaps">l</Emphasis>-pipecolic acid from the edible mushroom, <Emphasis Type="Italic">Sarcodon aspratus</Emphasis>, on angiotensin I-converting enzyme     

Masaaki Kiyoto  Shingo Saito  Kazuyuki Hattori  Nam-Seok Cho  Takaaki Hara  Yuzo Yagi  Masakazu Aoyama 《Journal of Wood Science》2008,54(2):179-181

The aqueous extract of the edible mushroom Sarcodon aspratus showed inhibitory effects against angiotensin I-converting enzyme (ACE). l-Pipecolic acid (l-piperidine-2-carboxylic acid) was isolated from a hot-water extract in a 0.02% yield as an active principle. The mode of inhibition of l-pipecolic acid was found to be competitive, whereas its d-isomer showed no significant inhibitory effects against ACE, suggesting that the configuration of the carboxyl group in the molecule plays an important role in the enzyme inhibition.  相似文献   

A selective medium to isolate airborne spores of Microdochium nivale,causing winter wheat scab     

Y. Hayashi  T. Kozawa  D. Aiuchi  M. Tani  M. Koike 《European journal of plant pathology / European Foundation for Plant Pathology》2014,138(2):247-256

Winter wheat scab in Hokkaido, Japan is caused predominantly by Gibberella zeae and Microdochium nivale and can result in significant yield losses. A selective medium for isolation of G. zeae was previously developed, but not for M. nivale. The purpose of this study therefore was to develop a selective medium for isolation of airborne spores of M. nivale. Based on the basic composition of Komada’s Fusarium-selective medium, carbon and nitrogen sources and the most suitable vitamin B component for the basal composition were examined. Hyphal growth of M. nivale was promoted when galactose was replaced with lactose and combined with L-asparagine, while aerial hyphal formation increased with thiamine hydrochloride as the vitamin B source. In antimicrobial composition, colony formation of other filamentous fungi was greatly inhibited by spiroxamine. Thiophanate methyl, to which M. nivale shows resistance, selectively inhibited the growth of Fusarium spp. only. Spore trapping using the selective medium was subsequently performed in a wheat field. M. nivale formed characteristic pinkish colonies on the selective medium in the case of contamination with other filamentous fungi, making differentiation easy. Overall, the findings show that LATTS medium developed in this study is effective for isolation of airborne spores of M. nivale.  相似文献   

Abnormal morphology in megalopae of the swimming crab,Portunus trituberculatus during seed production: causes and prevention          下载免费PDF全文

Shigeki Dan  Yuming Sui  Takaaki Kaneko  Satoshi Takeshima  Daisuke Ojima  Tatsuo Miyoshi  Kaoru Hamano  Masakazu Ashidate  Katsuyuki Hamasaki 《Aquaculture Research》2016,47(10):3189-3202

The occurrence of morphologically immature megalopae, which retain zoeal features such as dorsal spines and furcae of telson, is closely correlated with larval mass mortality during seed production of the swimming crab Portunus trituberculatus in Japanese hatcheries. To determine the cause of immature megalopal morphology, zoeae were reared with various supplementary schedules and density of diets (rotifer, Artemia and phytoplanktons including Chlorella vulgaris and Nannochloropsis oculata). In addition, to assess the relationship between immature morphology and endocrine control, the effect of causative dietary factor was compared with the effect of eyestalk ablation at various timing during zoeal development. Megalopal immature morphology was more distinct in Chlorella‐supplemented groups than in Nannochloropsis‐supplemented groups. High density Chlorella supplementation was associated with the highest incidence of immaturity and resulted in larval mass mortality. The premoult of the third zoeal stage was identified as a critical period at which Chlorella supplementation led to the highest incidence of immaturity. This critical period coincided with the critical period at which larval metamorphosis was regulated by the eyestalk neurosecretory system. Our results suggested that the occurrence of immature megalopal morphology under culture conditions is most likely caused by phytoplankton (especially, Chlorella) supplementation, which disrupts the endocrine regulation. On the basis of our results, we successfully prevented the occurrence of immature megalopal morphology in 500 L tanks by excluding the influence of phytoplankton before the critical period (i.e. discontinuing phytoplankton supplementation and supplying rotifer cultured with non‐phytoplankton materials).  相似文献   

Adsorption by coniferous leaves of chromium ions from effluent     

Nam-Seok Cho  Masakazu Aoyama  Kazuto Seki  Naotaka Hayashi  Shuichi Doi 《Journal of Wood Science》1999,45(3):266-270

The chromium adsorption ability of leaves from 34 conifer species were examined. Among them, deciduous conifer species, such asLarix, Ginkgo, Metasequia, andTaxodium, showed high ability to adsorb chromium ions. Factors affecting chromium adsorption were studied using larch (Larix leptolepis) leaves to determine the optimum adsorption conditions. The factors included solution pH, contact time, temperature, and the initial concentration of chromium ions. Maximum adsorption for Cr³⁺ was observed at pH 5, and maximum Cr⁶⁺ adsorption occurred at pH 3. The amount of Cr⁶⁺ adsorbed on the adsorbent increased rapidly during the first 4 h, then gradually increased, and finally reached equilibrium in 16 h. The adsorption rate of Cr³⁺ was somewhat slower than that of Cr⁶⁺. The adsorption isotherm for Cr⁶⁺ adsorption was composed of two straight lines, suggesting that the adsorbent could not practically reduce the concentration of Cr⁶⁺ in solution below 1.6 mg Cr/L Column experiments using larch leaf packing suggested that the practical operation could be controlled by monitoring the effluent pH.  相似文献   

Quantitative trait loci mapping for meat quality and muscle fiber traits in a Japanese wild boar x Large White intercross     

Nii M  Hayashi T  Mikawa S  Tani F  Niki A  Mori N  Uchida Y  Fujishima-Kanaya N  Komatsu M  Awata T 《Journal of animal science》2005,83(2):308-315

Three generations of a swine family produced by crossing a Japanese wild boar and three Large White female pigs were used to map QTL for various production traits. Here we report the results of QTL analyses for skeletal muscle fiber composition and meat quality traits based on phenotypic data of 353 F(2) animals and genotypic data of 225 markers covering almost the entire pig genome for all of the F(2) animals as well as their F(1) parents and F(0) grandparents. The results of a genome scan using least squares regression interval mapping provided evidence that QTL (<1% genome-wise error rate) affected the proportion of the number of type IIA muscle fibers on SSC2, the number of type IIB on SSC14, the relative area (RA) of type I on SSCX, the RA of type IIA on SSC6, the RA of type IIB on SSC6 and SSC14, the Minolta a* values of loin on SSC4 and SSC6, the Minolta b* value of loin on SSC15, and the hematin content of the LM on SSC6. Quantitative trait loci (<5% genome-wise error rate) were found for the number of type I on SSC1, SSC14, and SSCX, for the number of type IIA on SSC14, for the number of type IIB on SSC2, for the RA of type IIA on SSC2, for the Minolta b* value of loin on SSC3, for the pH of loin on SSC15, and for the i.m. fat content on SSC15. Twenty-four QTL were detected for 11 traits at the 5% genome-wise level. Some traits were associated with each other, so the 24 QTL were located on 11 genomic regions. In five QTL located on SSC2, SSC6, and SSC14, each wild boar allele had the effect of increasing types I and IIA muscle fibers and decreasing type IIB muscle fibers. These effects are expected to improve meat quality.  相似文献   

Preference for safflower oil in rats exposed to a cold environment under free-feeding conditions     

Saitoh M  Ishii T  Takewaki T  Nishimura M 《The Journal of veterinary medical science / the Japanese Society of Veterinary Science》2005,67(7):653-658

There are several benefits to a high-fat diet for animals exposed to cold, including improved tolerance to severe cold conditions and increased survival rates in cold environments. It is therefore of interest to examine whether animals exposed to cold will selectively consume lipids. We examined the intake of safflower oil (SO) by rats exposed to cold (4 +/- 2 degrees C) under a feeding condition in which the rats were given free access to SO. Rats exposed to cold consumed more SO than those housed at 25 +/- 2 degrees C. This finding suggests that rats prefer SO in a cold environment. There was no significant difference in the ratio of calories of SO ingested to that of matter (standard laboratory chow plus SO) ingested between rats exposed to cold and those at 25 +/- 2 degrees C. The high SO intake also affected cold tolerance and metabolite kinetics in the rats. Factors that affected the SO intake of rats exposed to cold are also discussed.  相似文献   

Surveillance of chronic wasting disease in sika deer, Cervus nippon, from Tokachi district in Hokkaido     

Kataoka N  Nishimura M  Horiuchi M  Ishiguro N 《The Journal of veterinary medical science / the Japanese Society of Veterinary Science》2005,67(3):349-351

Surveillance of chronic wasting disease (CWD) was conducted by performing Western blot analysis of tissue samples from 136 sika deer (Cervus nippon) killed by hunters in the Tokachi district of Hokkaido Island. No prion protein (PrPSc) associated with CWD was detected in any of the samples. To assess amino acid polymorphisms of the sika deer PrP gene, nucleotide sequencing of the PrP gene was performed. The only amino acid polymorphisms detected were 3 silent mutations at nucleotide positions 63, 225 and 408. These results suggest that sika deer in the Tokachi district are genetically homogeneous, and are not infected with CWD.  相似文献