RESUMEN
In plants, many invading microbial pathogens are recognized by cell-surface pattern recognition receptors, which induce defense responses. Here, we show that the ceramide Phytophthora infestans-ceramide D (Pi-Cer D) from the plant pathogenic oomycete P. infestans triggers defense responses in Arabidopsis. Pi-Cer D is cleaved by an Arabidopsis apoplastic ceramidase, NEUTRAL CERAMIDASE 2 (NCER2), and the resulting 9-methyl-branched sphingoid base is recognized by a plasma membrane lectin receptor-like kinase, RESISTANT TO DFPM-INHIBITION OF ABSCISIC ACID SIGNALING 2 (RDA2). 9-Methyl-branched sphingoid base is specific to microbes and induces plant immune responses by physically interacting with RDA2. Loss of RDA2 or NCER2 function compromised Arabidopsis resistance against an oomycete pathogen. Thus, we elucidated the recognition mechanisms of pathogen-derived lipid molecules in plants.
Asunto(s)
Proteínas de Arabidopsis , Arabidopsis , Ceramidas , Interacciones Huésped-Patógeno , Ceramidasa Neutra , Phytophthora infestans , Enfermedades de las Plantas , Arabidopsis/genética , Arabidopsis/inmunología , Arabidopsis/microbiología , Proteínas de Arabidopsis/genética , Proteínas de Arabidopsis/metabolismo , Ceramidas/metabolismo , Ceramidasa Neutra/genética , Ceramidasa Neutra/metabolismo , Phytophthora infestans/patogenicidad , Enfermedades de las Plantas/inmunología , Enfermedades de las Plantas/microbiología , Proteínas Serina-Treonina Quinasas/genética , Proteínas Serina-Treonina Quinasas/metabolismo , Receptores Mitogénicos/genética , Receptores Mitogénicos/metabolismoRESUMEN
The tumor promoter okadaic acid binds specifically to a particulate as well as a cytosolic fraction of various mouse tissues, e.g., skin, brain, lung and colon. The KD value was 21.7 nM for receptors in the particulate fraction and 1.0 nM for those in the cytosolic fraction of mouse skin. The specific binding of [3H]okadaic acid to the particulate fraction of mouse skin was inhibited dose-dependently by okadaic acid, but not okadaic acid tetramethyl ether, an inactive compound, or by other tumor promoters, such as 12-O-tetradecanoylphorbol-13-acetate and teleocidin. The results suggest a new pathway of tumor promotion mediated through the okadaic acid receptor(s).
Asunto(s)
Carcinógenos/metabolismo , Éteres Cíclicos/metabolismo , Piel/metabolismo , Animales , Encéfalo/metabolismo , Cromatografía DEAE-Celulosa , Colon/metabolismo , Citosol/metabolismo , Pulmón/metabolismo , Ratones , Ácido Ocadaico , Fosfoproteínas Fosfatasas/metabolismo , Proteínas Quinasas/metabolismo , Piel/enzimologíaRESUMEN
Hyperplastic nodules (HN) of the liver were induced in Charles River Sprague-Dawley rats (CD rats) and ACI rats fed a diet containing 30% bracken for 260 and 180 days, respectively. HN were also induced in high incidence in CD rats fed a diet containing the carcinogenic fractions of bracken extract.
Asunto(s)
Hígado/efectos de los fármacos , Extractos Vegetales/toxicidad , Plantas Comestibles , Animales , Femenino , Hiperplasia/inducido químicamente , Hígado/patología , Masculino , Ratas , Ratas Endogámicas , Factores SexualesRESUMEN
Isolation of the carcinogen in the boiling water extract of bracken fern was conducted by following the active principle with a carcinogenicity bioassay. Fractionation of the bracken extract was carried out using adsorption on resin (Amberlite XAD-2 and TOYOPEARL HW-40 (c] and organic solvent extraction. A diet containing each of the fractions was given to 7 female Charles River Sprague-Dawley rats (CD rats) of 4 weeks old, except for the second fraction. All 7 rats given the last carcinogenic fraction developed mammary and intestinal tumors and 5 rats had urinary bladder tumors. Ptaquiloside (PT) which induced mammary cancer in female CD rats and rho-hydroxystyrene glycosides were isolated from this fraction.
Asunto(s)
Carcinógenos/aislamiento & purificación , Plantas Tóxicas/análisis , Animales , Femenino , Neoplasias Mamarias Experimentales/inducido químicamente , Neoplasias Experimentales/inducido químicamente , Ratas , Ratas EndogámicasRESUMEN
The serologic activities of structurally related okadaic acid derivatives have been determined. Binding of [3H]okadaic acid to rabbit anti-okadaic acid is inhibited with equal effectiveness by okadaic acid, dinophysistoxin-1, acanthifolicin, okadaic acid tetramethyl ether, and okadaic acid spiroketal II. Okadaic acid spiroketal I, which lacks the F- and G-rings of okadaic acid, inhibits serologic binding about 60 times less effectively. The F- and G-rings of okadaic acid may comprise part of the epitopes recognized by some of the polyclonal antibodies.
Asunto(s)
Éteres Cíclicos/metabolismo , Animales , Especificidad de Anticuerpos , Reacciones Antígeno-Anticuerpo , Unión Competitiva , Éteres Cíclicos/inmunología , Éteres Cíclicos/aislamiento & purificación , Ácido Ocadaico , Piranos/inmunología , Piranos/aislamiento & purificación , Conejos/inmunología , Radioinmunoensayo , Compuestos de Espiro/farmacologíaRESUMEN
An okadaic acid immunogen, prepared by conjugation of okadaic acid to bovine albumin with carbodiimide, was used to immunize two rabbits. The rabbits responded by producing antibodies that neutralized okadaic acid's stimulation of arachidonic acid metabolism and this neutralization increased during the course of immunization. The immune sera bound 3H-okadaic acid and this binding also increased with repeated immunization. After absorption of the rabbit IgG with a goat anti-rabbit IgG, binding was reduced greater than 99%. The binding of okadaic acid to the antibodies in one antiserum was inhibited by as little as 0.2 pmoles of unlabelled okadaic acid. The apparent association constant for binding with this antiserum was 4.17 x 10(9) M-1 (35 degrees C). Maitotoxin, teleocidin, 12-O-tetradecanoylphorbol-13-acetate, aplysiatoxin, palytoxin and brevetoxin B when tested at 29, 228, 168, 169, 3.7 and 112 pmole levels, respectively, did not inhibit binding. The serologic and biological activities of okadaic acid after incubation for 60 min in 0.01 N HCl at 35 degrees C or at 100 degrees C at pH 7.2 were unaffected.
Asunto(s)
Éteres Cíclicos/análisis , Inmunoglobulina G/análisis , Inmunotoxinas/análisis , 6-Cetoprostaglandina F1 alfa/biosíntesis , 6-Cetoprostaglandina F1 alfa/metabolismo , Formación de Anticuerpos , Éteres Cíclicos/inmunología , Éteres Cíclicos/toxicidad , Ácido Ocadaico , RadioinmunoensayoRESUMEN
The genotoxicity of ptaquiloside (PT), recently isolated from bracken fern and shown to be carcinogenic, was examined by means of the hepatocyte primary culture/DNA-repair test. PT elicited clear unscheduled DNA synthesis with a dose-response effect. The result indicates that PT is a genotoxic carcinogen.
Asunto(s)
Carcinógenos/toxicidad , Reparación del ADN/efectos de los fármacos , Indanos , Plantas Tóxicas/análisis , Sesquiterpenos , Terpenos/toxicidad , Animales , Células Cultivadas , ADN/biosíntesis , Relación Dosis-Respuesta a Droga , Hígado/metabolismo , Masculino , Pruebas de Mutagenicidad , Ratas , Ratas Endogámicas ACIRESUMEN
This study completes the spectroscopic basis for a novel oligosaccharide microanalytical method, wherein a derivatization sequence provides monosaccharide subunits bearing two types of exciton-coupling chromophore groups ("bichromophoric") for circular dichroic spectroscopy, namely 4-bromobenzoate (lambda max 245 nm) and 4-methoxycinnamate (lambda max 311 nm). The 24 possible derivatives of methyl alpha-D-mannopyranoside bearing two chromophore and two acetate groups have been prepared and their c.d. spectra recorded. These spectra have been used to calculate the c.d. curves of the 14 possible tetrachromophic derivatives according to the pairwise additivity rule. The accuracy of these calculations has been demonstrated for six representative derivatives. The c.d. curves obtained here, together with curves of the corresponding D-glucose and D-galactose derivatives, comprise a set of 42 unique and distinctive spectra which can be utilized to identify sugars and their linkage patterns, and thus represent the basis for an alternative to methylation analysis which does not rely upon synthetic standards.
Asunto(s)
Metilglicósidos/análisis , Metilmanósidos/análisis , Oligosacáridos/análisis , Bromobenzoatos , Conformación de Carbohidratos , Cinamatos , Dicroismo Circular , Microquímica , Estándares de Referencia , EstereoisomerismoRESUMEN
Clavariopsins were isolated from the fermentation broth of Clavariopsis aquatica AJ 117363. Clavariopsins are cyclic depsipeptide antibiotics with the molecular weight of 1,153 and 1,139. Clavariopsins showed in vitro antifungal activity against not only Aspergillus fumigatus but also, although to a lesser extent, A. niger and Candida albicans.
Asunto(s)
Antibacterianos/aislamiento & purificación , Antibacterianos/farmacología , Antifúngicos/aislamiento & purificación , Antifúngicos/farmacología , Depsipéptidos , Hongos Mitospóricos/metabolismo , Animales , Antibacterianos/química , Antifúngicos/química , Aspergillus niger/efectos de los fármacos , Candida albicans/efectos de los fármacos , Fermentación , Ratones , Pruebas de Sensibilidad Microbiana , Hongos Mitospóricos/clasificación , Estructura Molecular , Péptidos CíclicosRESUMEN
The structures of new cyclic decadepsipeptides, clavariopsins A and B, were determined to be cyclo[-(R)-2-hydroxyisovaleryl-L-pipecoyl-L-MeVal-L-Val-L-MeAsp-L-MeIle-L-MeIle-Gly L-MeVal-L-Tyr(OMe)-] and cyclo[-(R)-2-hydroxyisovaleryl-L-pipecolyl-L-Val-L-Val-L-MeAsp-L-Melle-L-MeIle-Gly-L-MeVal-L-Tyr(OMe)-], respectively, by spectroscopic analyses, especially using 2D NMR techniques. The absolute stereochemistry was elucidated by the advanced Marfey's method and chiral HPLC analysis.
Asunto(s)
Antibacterianos/química , Hongos Mitospóricos/metabolismo , Péptidos , Cromatografía Líquida de Alta Presión , Espectroscopía de Resonancia Magnética , Conformación Molecular , Estructura MolecularRESUMEN
New bithiazole-type antibiotics, cystothiazoles A (C20H26N2O4S2) and B (C20H26N2O5S2), have been isolated from a culture broth of the myxobacterium, Cystobacter fuscus. The gross structures of these compounds were elucidated by spectroscopic analysis, and their absolute stereochemistry was determined by chemical degradation of cystothiazole A. Cystothiazole A inhibits fungi and human tumor cells, whereas it is inactive against bacteria. The antifungal activity appears to result from the inhibition of submitochondrial NADH oxidation. Although these compounds are structurally related to the known antibiotic myxothiazol, cystothiazole A was more active against fungi and less cytotoxic than myxothiazol.
Asunto(s)
Antibacterianos/aislamiento & purificación , Myxococcales/metabolismo , Tiazoles/aislamiento & purificación , Antibacterianos/química , Antibacterianos/farmacología , Fermentación , Conformación Molecular , Tiazoles/química , Tiazoles/farmacologíaRESUMEN
The process of occurrence of bright blindness, progressive retinal degeneration (PRD), in sheep was observed using two Suffolk ram lambs fed on a diet containing bracken powder. The first sign of the bright blindness was detected 4 months after the start of experiment. Based on these preliminary results, the amount of bracken powder necessary to induce PRD was estimated (experiment I). In the following experiment, ptaquiloside (PT), a norsesquiterpene glucoside of the illudane type isolated from bracken, which is a bracken carcinogen and a causative principle of cattle bracken poisoning was administered to two Suffolk ram lambs. It was clearly demonstrated in this experiment (experiment II) that PT present in bracken is also a causative principle of PRD.
Asunto(s)
Alimentación Animal , Indanos , Intoxicación por Plantas/veterinaria , Degeneración Retiniana/veterinaria , Sesquiterpenos , Enfermedades de las Ovejas , Terpenos/toxicidad , Animales , Médula Ósea/patología , Masculino , Células Fotorreceptoras/patología , Intoxicación por Plantas/patología , Retina/patología , Degeneración Retiniana/etiología , Degeneración Retiniana/patología , Ovinos , Terpenos/administración & dosificación , Terpenos/aislamiento & purificaciónRESUMEN
Acute bracken fern toxicity in a calf was reproduced with ptaquiloside, a norsesquiterpene glucoside, isolated from the boiling water extract of bracken fern. Ptaquiloside was dissolved in 500 ml of saline and administered by drench at increasing dosages for six days out of every seven for the following periods: 400 mg/day for 24 days, 800 mg/day for 14 days and 1600 mg/day for four days. Neutrophilic granulocytes began to decrease markedly around 50 days after the start of the experiment, and granulocytopenia continued for a further 35 days until the autopsy, despite the discontinuance of ptaquiloside administration. Thrombocytes showed a relatively slow depression and reached 1 X 10(5)/mm3 at the lowest level. The calf was autopsied 86 days after the start of administration of ptaquiloside. Sternal bone marrow was found to be mostly replaced with fat marrow and only small foci of erythropoietic cells and a small number of megakaryocytes remained.
Asunto(s)
Enfermedades de los Bovinos/etiología , Indanos , Extractos Vegetales/envenenamiento , Intoxicación por Plantas/veterinaria , Sesquiterpenos , Terpenos/envenenamiento , Agranulocitosis/etiología , Agranulocitosis/veterinaria , Animales , Bovinos , Femenino , Hemorragia/etiología , Hemorragia/veterinaria , Recuento de Leucocitos/veterinaria , Leucocitosis/etiología , Leucocitosis/veterinaria , Intoxicación por Plantas/etiología , Trombocitopenia/etiología , Trombocitopenia/veterinariaRESUMEN
In general, the root of a seaweed is poorly developed as compared with its thallus and is called the rhizoid or holdfast. In Laminaria, belonging to Phaeophyceae, although the thallus is used for food, the rhizoid is considered an unuseful natural resource. We attempted to detect anti-breast cancer substances from that resource. As a result, a substance having a weak absorptivity to aluminium oxide and Sephadex G-25 was found. According to analysis of the FAB-MS spectra and 1H NMR spectra, the substance was identified as tryptophan, an amino acid. Finally, it was concluded by a chiral column-HPLC method that the tryptophan was the L-form.
Asunto(s)
Antineoplásicos/farmacología , Neoplasias de la Mama/patología , Algas Marinas/química , Triptófano/aislamiento & purificación , Triptófano/farmacología , Humanos , Células Tumorales Cultivadas/efectos de los fármacosAsunto(s)
Indanos , Microcirculación/efectos de los fármacos , Sesquiterpenos , Terpenos/farmacología , Animales , Edema/inducido químicamente , Edema/patología , Femenino , Hiperemia/inducido químicamente , Hiperemia/patología , Inyecciones Intravenosas , Riñón/patología , Conejos , Terpenos/administración & dosificación , Terpenos/envenenamiento , Vejiga Urinaria/patologíaRESUMEN
Termitomycesphins E and F, novel cerebrosides that are hydroxylated around the middle of the long-chain base (LCB), have been isolated from the edible Chinese mushroom Termitomyces albuminosus (Berk.) Heim. ('Jizong' in Chinese) together with termitomycesphins A-D, and shown to induce neuronal differentiation in rat PC12 cells. Their stereostructures have been determined based on their chemical derivatization and spectroscopic analysis. The major cerebroside obtained from the same mushroom was not hydroxylated around the middle of the LCB and was inactive against PC12 cells, suggesting the importance of the extra hydroxyl group on LCB. The Di- and tetrahydroxylation of this inactive cerebroside resulted in the enhancement of its neuritogenic activity.
Asunto(s)
Agaricales/química , Cerebrósidos/farmacología , Animales , Diferenciación Celular/efectos de los fármacos , Cerebrósidos/química , Cerebrósidos/aislamiento & purificación , Hidroxilación , Neuronas/citología , Neuronas/efectos de los fármacos , Células PC12 , RatasRESUMEN
A search for neuritogenic compounds in Chinese herbs resulted in the isolation of two known substances, ostruthin and (-)-bornyl ferulate, from Notopterygium incisum (and/or N. forbesii). Both compounds induced comparable neurite-like structures in 20% of rat PC12 cells at 2 micrograms/ml, and showed cytotoxicity at concentrations higher than 3 micrograms/ml.
Asunto(s)
Ácidos Cumáricos/farmacología , Medicamentos Herbarios Chinos/farmacología , Umbeliferonas/farmacología , Animales , Diferenciación Celular/efectos de los fármacos , Neuritas/efectos de los fármacos , Células PC12 , RatasRESUMEN
A new bromoallene metabolite, named aplysiallene, was isolated from the Japanese sea hare, Aplysia kurodai, as an Na, K-ATPase inhibitor. Its structure was elucidated by spectroscopic methods. The known metabolites, laurinterol and debromolaurinterol, isolated from this animal were also evaluated for their Na, K-ATPase inhibitory activity.
Asunto(s)
Aplysia/química , Compuestos Bicíclicos Heterocíclicos con Puentes/química , Compuestos Bicíclicos Heterocíclicos con Puentes/aislamiento & purificación , Inhibidores Enzimáticos/aislamiento & purificación , Furanos/química , Furanos/aislamiento & purificación , ATPasa Intercambiadora de Sodio-Potasio/antagonistas & inhibidores , Animales , Compuestos Bicíclicos Heterocíclicos con Puentes/farmacología , Inhibidores Enzimáticos/química , Inhibidores Enzimáticos/farmacología , Furanos/farmacología , Técnicas In Vitro , Espectroscopía de Resonancia Magnética , Estructura Molecular , Espectrometría de Masa Bombardeada por Átomos VelocesRESUMEN
The interaction of okadaic acid and a protein phosphatase, which is the receptor for a tumor promoter, okadaic acid, was studied. [27-3H]Methyl 7-O-(4-azidobenzoyl)okadaate was synthesized and protein phosphatase 2A, which consists of two regulatory subunits of 65 kDa and 42 kDa and a catalytic subunit of 37 kDa, was purified from bovine brain. After UV irradiation of the reaction mixture, [3H]methyl 7-O-(4-azidobenzoyl)okadaate covalently bound to the catalytic subunit, but not to the two regulatory subunits. These results strongly suggest that okadaic acid, a potent inhibitor of protein phosphatases, binds specifically to the catalytic subunit rather than to the other regulatory subunits.