Cerebroside elicitor confers resistance to fusarium disease in various plant species     

Umemura K  Tanino S  Nagatsuka T  Koga J  Iwata M  Nagashima K  Amemiya Y 《Phytopathology》2004,94(8):813-818

ABSTRACT In the rice blast fungus pathosystem, cerebroside, a compound categorized as a sphingolipid, was found in our previous study to be a non-racespecific elicitor, which elicits defense responses in rice. Here we describe that cerebroside C is produced in diverse strains of Fusarium oxysporum, a common soilborne agent of wilt disease affecting a wide range of plant species. In addition, some type of cerebroside elicitor involving cerebroside A, B, or C was detected in other soilborne phytopathogens, such as Pythium and Botrytis. Treatment of lettuce (Lactuca sativa), tomato (Lycopersicon esculentum), melon (Cucumis melo), and sweet potato (Ipomoea batatas) with cerebroside B resulted in resistance to infection by each pathogenic strain of F. oxysporum. Induction of pathogenesis-related genes and H(2)O(2) production by treatment with cerebroside B were observed in tomato root tissues. The cerebroside elicitor showed no antifungal activity against F. oxysporum in vitro, indicating that the cerebroside elicitor activates defense mechanisms to confer resistance to Fusarium disease. These results suggest that cerebroside functions as a non-race-specific elicitor in a wide range of plant-phytopathogenic fungus interactions. Additionally, cerebroside elicitor serves as a potential biologically derived control agent.  相似文献   

8-Difluoromethoxy-4-quinolone derivatives as anti-feline immunodeficiency virus (FIV) agents: important structural features for inhibitory activity of FIV replication     

Kashiwase H  Katsube T  Kimura T  Nishigaki T  Yamashita M 《The Journal of veterinary medical science / the Japanese Society of Veterinary Science》2000,62(5):499-504

The inhibitory activities of various 8-difluoromethoxy-4-quinolone derivatives against feline immunodeficiency virus (FIV) replication in the chronically infected cell line P-CrFK were investigated. Certain derivatives were found to inhibit FIV production from P-CrFK cells in a dose-dependent manner without exhibiting cytotoxic effects at inhibitory concentrations. Based on this study, the structures important for anti-FIV activity are suggested to be (i) a carboxyl group at position C-3, and (ii) an aromatic modification at position 4 of the C-7 piperazinyl moiety.  相似文献   

Positive reactions to common allergens in 42 atopic dogs in Japan     

Masuda K  Sakaguchi M  Fujiwara S  Kurata K  Yamashita K  Odagiri T  Nakao Y  Matsuki N  Ono K  Watari T  Hasegawa A  Tsujimoto H 《Veterinary immunology and immunopathology》2000,73(2):193-204

Clinically important allergens for the diagnosis and treatment of atopic dermatitis vary geographically. In order to identify the most prevalent allergens in atopic dogs in Japan, 42 dogs with a clinical diagnosis of atopy were tested using both in vivo (intradermal skin test (IDST)) and in vitro (antigen-specific IgE assay) allergy tests. Allergens used for IDST included 26 allergen extracts from eight allergen groups: trees, weeds, grasses, house dust mites (HDM), molds, foods, epithelia, and arthropods. Immunodot assay was used to measure antigen-specific IgE against 24 allergens from these eight groups and against fish such as cod and sole. In the 42 dogs, the most common positive allergen reaction was to HDM on both IDST (29/42 dogs or 69%) and in vitro testing (23/42 or 54.8%). The second most frequent positive allergen reaction was to Japanese cedar pollen (21/42 or 50.0% for IDST and 7/42 or 16.7% for in vitro testing). In both tests, less than 20% of dogs had positive reactions to molds or foods. Positive reactions to cat epithelia were frequently found on IDST, but rarely found on in vitro testing. Agreement between the two tests was found in 26 instances: HDM (21 dogs), Japanese cedar pollen (five dogs) and wheat (one dog). In this study, the two most common allergens involved in atopic dermatitis in dogs in Japan were HDM and Japanese cedar pollen.  相似文献   

Beta-cyanoalanine synthase as a molecular marker for induced resistance by fungal glycoprotein elicitor and commercial plant activators     

Takahashi H  Ishihara T  Hase S  Chiba A  Nakaho K  Arie T  Teraoka T  Iwata M  Tugane T  Shibata D  Takenaka S 《Phytopathology》2006,96(8):908-916

ABSTRACT The biocontrol agent Pythium oligandrum produces glycoprotein elicitor in the cell wall fraction, designated CWP, and induces resistance to a broad range of pathogens. To understand the mechanism of CWP-induced resistance to pathogens, gene expression at the early stage of CWP treatment in tomato roots was analyzed using a cDNA array. At 4 h after CWP treatment, 144 genes were up-regulated and 99 genes were down-regulated. In the 144 up-regulated genes, nine genes exhibited about eightfold increased expression. Analysis of the response of these nine genes to three commercial plant activators indicated that a high level of one gene, beta-cyanoalanine synthase gene (LeCAS) encoding hydrogen cyanide (HCN) detoxification enzyme, was stably induced in tomato roots by such treatment. However, expression of LeCAS was not significantly induced in tomato roots at 4 h by abiotic stresses, whereas only a very low level of induction of such expression by cold stress was observed. This LeCAS expression was also induced after exogenous treatment with a low level of 1-amino-cyclopropane-1-carboxylate as the precursor of ethylene, but not with either salicylic acid or methyl jas-monate. The induction of LeCAS expression in CWP-treated and plant activator-treated roots is likely to be caused by the detoxification of HCN during ethylene production. Transient activation of LeCAS expression caused by ethylene production in tomato roots may be a general phenomenon in fungal elicitor-induced and synthetic plant activator-induced resistance. LeCAS seems to be useful for screening possible novel plant activators for plant protection against pathogens.  相似文献   

Lysosomal glycosphingolipid recognition by NKT cells   总被引：2，自引：0，他引：2  

Zhou D  Mattner J  Cantu C  Schrantz N  Yin N  Gao Y  Sagiv Y  Hudspeth K  Wu YP  Yamashita T  Teneberg S  Wang D  Proia RL  Levery SB  Savage PB  Teyton L  Bendelac A 《Science (New York, N.Y.)》2004,306(5702):1786-1789

NKT cells represent a distinct lineage of T cells that coexpress a conserved alphabeta T cell receptor (TCR) and natural killer (NK) receptors. Although the TCR of NKT cells is characteristically autoreactive to CD1d, a lipid-presenting molecule, endogenous ligands for these cells have not been identified. We show that a lysosomal glycosphingolipid of previously unknown function, isoglobotrihexosylceramide (iGb3), is recognized both by mouse and human NKT cells. Impaired generation of lysosomal iGb3 in mice lacking beta-hexosaminidase b results in severe NKT cell deficiency, suggesting that this lipid also mediates development of NKT cells in the mouse. We suggest that expression of iGb3 in peripheral tissues may be involved in controlling NKT cell responses to infections and malignancy and in autoimmunity.  相似文献   

The structure of importin-beta bound to SREBP-2: nuclear import of a transcription factor     

Lee SJ  Sekimoto T  Yamashita E  Nagoshi E  Nakagawa A  Imamoto N  Yoshimura M  Sakai H  Chong KT  Tsukihara T  Yoneda Y 《Science (New York, N.Y.)》2003,302(5650):1571-1575

  相似文献   

Polyhydroxylated alkaloids isolated from mulberry trees (Morusalba L.) and silkworms (Bombyx mori L.)   总被引：2，自引：0，他引：2  

Asano N  Yamashita T  Yasuda K  Ikeda K  Kizu H  Kameda Y  Kato A  Nash RJ  Lee HS  Ryu KS 《Journal of agricultural and food chemistry》2001,49(9):4208-4213

New polyhydroxylated alkaloids, (2R,3R,4R)-2-hydroxymethyl-3,4-dihydroxypyrrolidine-N-propionamide from the root bark of Morus alba L., and 4-O-alpha-D-galactopyranosyl-calystegine B(2) and 3 beta,6 beta-dihydroxynortropane from the fruits, were isolated by column chromatography using a variety of ion-exchange resins. Fifteen other polyhydroxylated alkaloids were also isolated. 1-Deoxynojirimycin, a potent alpha-glucosidase inhibitor, was concentrated 2.7-fold by silkworms feeding on mulberry leaves. Some alkaloids contained in mulberry leaves were potent inhibitors of mammalian digestive glycosidases but not inhibitors of silkworm midgut glycosidases, suggesting that the silkworm has enzymes specially adapted to enable it to feed on mulberry leaves. The possibility of preventing the onset of diabetes and obesity using natural dietary supplements containing 1-deoxynojirimycin and other alpha-glucosidase inhibitors in high concentration is of great potential interest.  相似文献   

Predation on fish larvae by moon jellyfish <Emphasis Type="Italic">Aurelia aurita</Emphasis> under low dissolved oxygen concentrations   总被引：1，自引：0，他引：1  

Jun?ShojiEmail author  Reiji?Masuda  Yoh?Yamashita  Masaru?Tanaka 《Fisheries Science》2005,71(4):748-753

ABSTRACT:   Laboratory experiments were conducted to test the hypothesis that low dissolved oxygen concentrations have the potential to enhance the predation rate on fish larvae by moon jellyfish Aurelia aurita which is increasing in abundance in the coastal waters of Japan. Larvae of the red sea bream Pagrus major in four size classes (2.9, 4.1, 6.2 and 8.6 mm in standard length) were used as prey in a short-term predation experiment. No change in the bell contraction rate of the jellyfish (mean bell diameter, 100.4 ± 10.2 mm) was observed at the oxygen concentrations tested (1, 2 and 4 mg/L, and air-saturated, 5.5–6.0 mg/L), suggesting a strong tolerance to a decline in the oxygen concentration. More than 80% of the 2.5 and 4.1-mm size-class larvae were predated on by the jellyfish at all oxygen concentrations during the 15-min trials in 10-L tanks. The 6.2 and 8.6-mm size-class larvae were able to escape from the jellyfish apparently due to their developed swimming ability at the two higher dissolved oxygen concentrations. There was an increase in predation on larvae of these two size classes at the two lower dissolved oxygen concentrations. Predation by moon jellyfish on fish larvae can be more intense at low dissolved oxygen concentrations that commonly occur in the coastal waters of Japan.  相似文献   

Radula development in abalone Haliotis discus hannai from larva to adult in relation to feeding transitions   总被引：1，自引：0，他引：1  

Tomohiko Kawamura  Rodney D Roberts  Yoh Yamashita 《Fisheries Science》2001,67(4):596-605

ABSTRACT: The radula morphology of Haliotis discus hannai was examined by scanning electron microscope from the larval to the adult stage. The radula of competent larvae contained 11–13 transverse rows of teeth after 6–7 days at 20°C. The number of rows increased to 25–30 during the first several days after settlement, but then remained approximately constant throughout the post-larval period, increasing again in abalone larger than 4 mm in shell length (SL). In post-larvae < ~1 mm SL, only two pairs of lateral teeth (L1, L2) were present in the larval radula. An additional three pairs of lateral teeth (L3–L5) were added progressively as post-larvae grew from 0.9 mm to 1.9 mm SL. Marginal teeth were added steadily from one pair in larvae to 30–40 pairs at 3–4 mm SL, 70–80 pairs in 30–40 mm juveniles, and 70–90 pairs in 90–100 mm adults. The serrations on the working edges of the rachidian (R) and lateral teeth became less pronounced as the abalone grew. Nearly all serrations disappeared from the rachidian (R) and inner lateral teeth (L1, L2) by ~2 mm SL, and from the outer lateral teeth (L3–L5) by 20 mm SL. For abalone larger than 1.5 mm SL, the L3–L5 teeth became longer and more pointed, which increased the space between adjacent rows of teeth. Post-larvae < 1 mm SL had highly curved teeth with clearance angles of approximately or less than zero, whereas larger abalone had positive clearance angles. These radula developments appear to be related to transitions in feeding habits from microbial to macroalgal diets.  相似文献   

Distinct regional profiles of trace element content in muscle of Japanese eel Anguilla japonica from Japan, Taiwan, and China   总被引：1，自引：0，他引：1  

Yumiko Yamashita  Yuji Omura  Emiko Okazaki 《Fisheries Science》2006,72(5):1109-1113

Trace element distribution patterns were examined in Japanese eel from five Asian regions for the purpose of identifying the elements and patterns that could be used to determine provenance. Distinctive patterns were found in eels from the Japanese prefectures of Miyazaki, Kagawa, and Shizuoka, and from Taiwan and China. The levels of six trace elements, selenium, mercury, copper, manganese, zinc, and arsenic, in muscle tissue varied among eels of different origins, and factorial analysis of the elemental patterns showed that Factor 1 was attributable to selenium and mercury levels and Factor 2 to zinc and copper levels. Multivariate analysis showed that the patterns of elemental composition in fish muscle were mainly differentiated by these two factors.  相似文献