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1.
Administration of (13)C labeled acetates ([1-(13)C], [2-(13)C] and [1,2-(13)C(2)] to Lasiodiplodia theobromae showed the tetraketide origins of both theobroxide, a potato-tuber inducing substance [1, (1S, 2R, 5S, 6R)-3-methyl-7-oxa-bicyclo[4.1.0]hept-3-en-2,5-diol]) and its carbonyldioxy derivative [2, (1S, 4R, 5S, 6R)-7,9-dioxa-3-methyl-8-oxobicyclo [4.3.0]-2-nonene-4,5-diol]. The incorporation of acetate-derived hydrogen into 1 and 2 was studied using [2-(2)H(3), 2-(13)C]acetate. Three and one deuterium atoms were incorporated at one methyl and epoxy carbons, respectively. The observed loss of deuterium atoms from the methyl group suggests a considerable amount of exchange from the methyl group of [2-(2)H(3), 2-(13)C]acetate during biosynthesis of 1 and 2. Incorporation of [1-(13)C]- and [1,2-(13)C(2)]acetates indicates the carbonyl carbon of the carbonyldioxy derivative is derived from the carboxy carbon of the precursor.  相似文献   

2.
Aims:  To find out the cumulative effect of the nutritional parameters and to enhance the production of jasmonic acid (JA) in static fermentation by Lasiodiplodia theobromae using response surface methodology (RSM).
Method and Results:  Malt extract, sucrose, NaNO3 and MgSO4.7H2O were analysed by a 30-trial central composite design using RSM for optimizing their concentrations in the medium and the effect of their mutual interaction on JA production. Sucrose and NaNO3 were found highly significant in influencing the JA production. Malt extract and MgSO4.7H2O showed an effect on the JA production in interaction with other variables. When the optimum values of the parameters obtained through RSM (19·95 g l−1 malt extract, 50 g l−1 sucrose, 7·5 g l−1 NaNO3 and 3·51 g l−1 MgSO4.7H2O) were applied, 32% increase in JA production (299 mg l−1) was observed in comparison with 225 mg l−1 of JA produced with same media components not analysed by RSM and subsequently validated the statistical model.
Conclusions:  Increase in JA production was achieved by optimizing the nutritional parameters.
Significance and Impact of the Study:  This is the first report of using RSM for optimizing a medium for JA production. It resulted in an increase in JA production without augmentation of costly additives.  相似文献   

3.
He G  Matsuura H  Yoshihara T 《Phytochemistry》2004,65(20):2803-2807
Lasiodiplodia theobromae is known as a multi-infectious microorganism that causes considerable crop damage, particularly to tropical fruits. When the fruits are infected by L. theobromae, the typical symptom is the appearance of black spots on the surface of the infected fruit. When injected in to the peel of banana, the culture filtrate of L. theobromae induced formation of black spots. The structure of the isolated compound responsible for this effect was determined to be (3S,4R)-3-carboxy-2-methylene-heptan-4-olide on the basis of analysis of MS, IR, and 1H and 13C NMR spectroscopic data, including HMQC, HMBC, and 1H-1H COSY experiments. The active compound was not only isolated from the culture filtrate derived from potato dextrose medium, but also from the extract of infected peels of bananas.  相似文献   

4.
G Rebell  R K Forster 《Sabouraudia》1976,14(2):155-170
Four cases of human keratitis caused by the tropical fungus Lasiodiplodia theobromae have been encountered in Miami, Florida bringing to 8 the number of cases reported in the world literature. Two of the ulcers were mild. Three patients recovered without severe impairment of vision after topical polyene treatment, but 1 patient with a severe ulcer required therapeutic keratoplasty after 11 days of topical natamycin. Histopathology revealed fungus deep in the cornea, invading Descemet's membrane. L. theobromae appeared to have collagenase activity in vitro. Inoculation of L. theobromae into the corneas of rabbits produced progressive ulcers. The fungus was endemic in Miami on home grown and imported bananas. Polyene antimycotic antibiotics were fungicidal for L. theobromae in vitro. Thiabendazole was effectively fungistatic but varied in fungicidal effect. Clotrimazole and miconazole were only incompletely fungistatic. Of 7 strains of L. theobromae tested, 4 were relatively resistant to 5-flurocytosine.  相似文献   

5.
An administration study of 2H-labeled precursors showed that the 9-hydroxydecanoyl unit, the acyl intermediate of lasiodiplodin (1), was also the intermediate of (5S)-5-hydroxylasiodiplodin (2) in Lasiodiplodia theobromae. The incorporation of [O-methyl-2H3]-lasiodiplodin (6) into 2 indicated that hydroxylation at C-5 occurred after cyclization.  相似文献   

6.
Biosynthesis of jasmonic Acid by several plant species   总被引:23,自引:13,他引:23       下载免费PDF全文
Six plant species metabolized 18O-labeled 12-oxo-cis,cis-10,15-phytodienoic acid (12-oxo-PDA) to short chain cyclic fatty acids. The plant species were corn (Zea mays L.), eggplant (Solanum melongena L.), flax (Linum usitatissimum L.), oat (Avena sativa L.), sunflower (Helianthus annuus L.), and wheat (Triticum aestivum L.). Among the products was jasmonic acid, a natural plant constituent with growth-regulating properties. The pathway is the same as the one recently reported by us for jasmonic acid synthesis in Vicia faba L. pericarp. First, the ring double bond of 12-oxo-PDA is saturated; then β-oxidation enzymes remove six carbons from the carboxyl side chain of the ring. Substrate specificity studies indicated that neither the stereochemistry of the side chain at carbon 13 of 12-oxo-PDA nor the presence of the double bond at carbon 15 was crucial for either enzyme step. The presence of enzymes which convert 12-oxo-PDA to jasmonic acid in several plant species indicates that this may be a general metabolic pathway in plants.  相似文献   

7.
Muiridin, a spore-specific protein of the fungus Botryodiplodia theobromae, comprises about 25% of the mature pycnidiospore protein. It has an apparent molecular weight of 16,000 to 17,000 and is rich in glutamine, asparagine, and arginine. Muiridin is synthesized in developing spores via a precursor with an apparent molecular weight of 24,000. Two other polypeptides present in young developing spores with apparent molecular weights of 18,000 and 15,000 are immunologically related to muiridin. We propose a pathway for muiridin synthesis. Muiridin is actively degraded during the germination of spores from 30-day-old cultures. This degradation is independent of exogenous amino acids in the germination medium. In contrast, glutamine and, to a lesser extent, asparagine partially inhibit the degradation of muiridin during germination of spores from 7-day-old cultures.  相似文献   

8.
One function of the volatiles produced by the fungus Lasiodiplodia theobromae was supposed to be ecological, as an insect attractant, which could get the attracted insects to be a vector of the fungal spores. L. theobromae, a mellein-producing fungus, was isolated from the outer surface of a danaid butterfly, Idea leuconoe. Ingestion by the butterfly of mellein on some plant tissues that contained mellein from 0.3 to 11 ppm was observed in the field and also in an insectarium. All these plant tissues were infected with L. theobromae, therefore, the mellein was concluded to be produced by the fungi. These observation suggests the presence of a kind of mutualistic relation between Idea leuconoe and L. theobromae associated with mellein, which is a suspected sex pheromone of the butterfly, accumulated in its hairpencil.  相似文献   

9.
Genetic stability in a population of a plant pathogenic fungus over time   总被引:10,自引:1,他引:9  
Collections of the plant pathogenic fungus Mycosphaerella graminicola were made from the same field of wheat over a 3-year period. The field was planted with small plots containing four varieties of wheat grown in pure stand and in all possible two-, three- and four-way mixtures. In each year, the wheat field was recolonized by a local source of inoculum of unknown origin. Allele frequencies at 10 RFLP loci were compared at two different times within a growing season and over the 3-year period. No significant differences in allele frequencies were found for any of the RFLP loci over any of the time periods. DNA fingerprints were used to identify clones produced by asexual reproduction. Genotypic diversity based on the frequency of each clone was compared for each collection. No significant changes in genotypic diversity were found within a year or between years. Identical genotypes were found in the field at different times within a season, but no clones were conserved between years. No clone existed in a high frequency in any year, suggesting that selection for particular asexual lineages was weak. The founding population each year probably originated from wind-borne ascospores of the teleomorph, which may exist as an indigenous population on alternative hosts, such as Poa annua (annual bluegrass).  相似文献   

10.
A case report and review of literature is reported of a rare case of fungal keratitis from eastern India. A 32-year-old woman with a history of vegetative trauma presented with keratitis in left eye. Microbiological examination of corneal scraping showed refractile hyphae with aseptate branching filaments and black pigmented colonies on multiple solid agar medium. Organism was identified from culture using D1/D2 region of LSU (Large Sub Unit: 28S rDNA)-based molecular technique. PCR amplified a band with a sequence that was 100?% homologous with Lasiodiplodia theobromae. The organism was susceptible to amphotericin B and voriconazole and demonstrated resistance to itraconazole and fluconazole. A therapeutic keratoplasty was performed following non-responsiveness to initial topical voriconazole (2?%) therapy. Recurrence in graft was controlled with topical voriconazole and intracameral amphotericin B. However, the graft failed at the end of 3?months. L. theobromae is a rare cause of fungal keratitis. Management of these cases is difficult, often involving surgical procedures.  相似文献   

11.
Occurrence of the plant growth regulator jasmonic acid in plants   总被引:17,自引:0,他引:17  
The natural occurrence of jasmonic acid and its methyl ester in plants has been studied using different methods such as GC, GC-MS, HPLC, radioimmunoassay, and bioassay. Jasmonic acid was detected in several Leguminosae plants and a number of species belonging to nine other Angiospermae families. Highest amounts occurred in fruit parts, especially the immature pericarp, but it was found also in flowers and vegetative plant parts, e.g. leaves, stems, and germs. Young apple fruits contain both jasmonic acid and methyl jasmonate, and in Douglas fir, the only Gymnospermae species studied, only the methyl ester could be detected. Jasmonic acid is discussed as an endogenous plant growth regulator widely distributed in higher plants.  相似文献   

12.
A novel potato micro-tuber-inducing compound was isolated from the culture broth of Lasiodiplodia theobromae Shimokita 2. The structure of the isolated compound was determined as (3R,6S)-6-hydroxylasiodiplodin by means of spectroscopic analyses, the modified Mosher method, and chemical conversion. The compound showed potato micro-tuber-inducing activity at a concentration of 10(-4) M, using the culture of single-node segments of potato stems in vitro.  相似文献   

13.
An effective way to study the infection mechanisms of fungal pathogens is to disrupt their genes via transformation in both targeted and random manners. This isolates the mutants that exhibit altered virulence. In this paper, we report the successful transformation of Magnaporthe grisea, the causal agent for rice blast, that is mediated by Agrobacterium tumefaciens. Employing the binary vector pBHt2, which carries the bacterial hygromycin B phosphotransferase gene under the control of the Aspergillus nidulans trpC promoter as a selectable marker, led to the production of 500 to > 1,000 hygromycin B-resistant transformants per 1 x 10(6) conidia of M. grisea. The transformation efficiency is correlated with the number of A. tumefaciens cells used, pre-treating bacterial cells with acetosyringone prior to co-cultivation with fungal spores, and the duration of co-cultivation. All of the transformants tested remained mitotically stable, maintaining their hygromycin B resistance after several generations of growth in the absence of hygromycin B. A genomic Southern blot analysis showed that over 60% of the transformants contained a single T-DNA insert on their genome. Considering the efficiency and flexibility of A. tumefaciens-mediated transformation (ATMT), this technique offers highly efficient means for characterizing the genes that are important for the pathogenicity of M. grisea.  相似文献   

14.
The natural occurrence of jasmonic acid and its methyl ester in plants has been studied using different methods such as GC, GC-MS, HPLC, radioimmunoassay, and bioassay. Jasmonic acid was detected in several Leguminosae plants and a number of species belonging to nine other Angiospermae families. Highest amounts occurred in fruit parts, especially the immature pericarp, but it was found also in flowers and vegetative plant parts, e.g. leaves, stems, and germs. Young apple fruits contain both jasmonic acid and methyl jasmonate, and in Douglas fir, the only Gymnospermae species studied, only the methyl ester could be detected. Jasmonic acid is discussed as an endogenous plant growth regulator widely distributed in higher plants.  相似文献   

15.
Detoxification of an antifungal monoterpene terpinolene (1) by the plant pathogenic fungus Botrytis cinerea afforded hydroxlyated metabolites 2,3-dihydro-3beta,6beta-dihydroxy-terpinolene (2) (39%) and 2,3-dihydro-1alpha,3alpha-dihydroxy-terpinolene (3) (20%), respectively. Terpinolene showed good levels of antifungal activity while both the metabolites were inactive against another plant pathogenic fungus Cladosporium herbarun.  相似文献   

16.
The biosynthesis of jasmonic acid: a physiological role for plant lipoxygenase   总被引:30,自引:0,他引:30  
Linolenic acid was converted to a cyclic product, 12-oxo-phytodienoic acid, by lipoxygenase and hydroperoxide cyclase enzymes present in Vicia faba pericarp. Isotope labeling studies in which [U-14C] 12-[180] oxo-phytodienoic acid was incubated with thin sections of pericarp tissue showed that 12-oxo-phytodienoic acid is a biosynthetic precursor to jasmonic acid, a plant growth regulator which promotes senescence. Key enzymes proposed for this pathway are a reductase enzyme which reduces a double bond in the cyclopentenone ring, and beta-oxidation enzymes which remove six carbons from the carboxyl end of the molecule.  相似文献   

17.
Jasmonate signaling plays a critical role in protecting plants from pathogens or insect attacks and in limiting damage from abiotic stress. Many events contribute to the regulation of jasmonic acid (JA) synthesis during abiotic or biotic stress, but the details of the underlying mechanism remain unclear. In this Mini-Review paper, we discuss the possible roles of reactive oxygen species (ROS), nitric oxide (NO), calcium influx and mitogen-activated protein kinase (MAPK) cascade during JA synthesis or JA signal transduction.Key words: jasmonic acid, singal, transductionJasmonic acid (JA) is a member of the jasmonate group of plant hormones; it is biosynthesized from linolenic acid by the octadecanoid pathway.1 The main functions of this hormone are growth related, including growth inhibition, senescence and leaf abscission. It also plays an important role in plant response to wounding and in systemic resistance. JA has a structure similar to that of mammal prostaglandins and is synthesized from alpha-linolenic acid, which is a C-18 poly-unsaturated fatty acid. Lipoxygenase, allene oxide synthase and allene oxide cyclase are the putative key enzymes for JA synthesis; these enzymes have chloroplast transit peptides that direct their import into chloroplasts. JA can be conjugated with amino acids, namely, leucine, valine, isoleucine and the sugar, B-glucoside using UDP-glucose. (-)-JA and (-)-methyl jasmonate are major JAs in plants. Methyl jasmonate (MeJA) in particular is a strong candidate for airborne signals that mediate interplant communication for defense responses. JA and its derivates induce the production of vegetative storage proteins, osmotin, thionin (antifungal) and defensin. It also induces enzymes related to phytoalexin, chalcone synthase, phenylalanine ammonia lyase (PAL), and hydroxymethylglutaryl-COA reductase; it also induces protease inhibitors to suppress the insect growth. JA and ethylene induce PR-3, PR-4 and PDF 1.2 chitinases (CHI-B) and hevein-like protein. In plants, ROS, Calcium ion influx, MAP kinase cascade, and NO, a novel signaling molecule are involved in the JA octadecanoid signal pathway.14  相似文献   

18.
A novel potato micro-tuber-inducing compound was isolated from the culture broth of Lasiodiplodia theobromae Shimokita 2. The structure of the isolated compound was determined as (3R,6S)-6-hydroxylasiodiplodin by means of spectroscopic analyses, the modified Mosher method, and chemical conversion. The compound showed potato micro-tuber-inducing activity at a concentration of 10?4 M, using the culture of single-node segments of potato stems in vitro.  相似文献   

19.
We examined the biosynthetic pathway of abscisic acid (ABA) after isopentenyl diphosphate in a fungus, Cercospora cruenta. All oxygen atoms at C-1, -1, -1', and -4' of ABA produced by this fungus were labeled with (18)O from (18)O(2). The fungus did not produce the 9Z-carotenoid possessing gamma-ring that is likely a precursor for the carotenoid pathway, but produced new sesquiterpenoids, 2E,4E-gamma-ionylideneethane and 2Z,4E-gamma-ionylideneethane, along with 2E,4E,6E-allofarnesene. The fungus converted these sesquiterpenoids labeled with (13)C to ABA, and the incorporation ratio of 2Z,4E-gamma-ionylideneethane was higher than that of 2E,4E-gamma-ionylideneethane. From these results, we concluded that C. cruenta biosynthesized ABA by the direct pathway via oxidation of ionylideneethane with molecular oxygen following cyclization of allofarnesene. This direct pathway via ionylideneethane in the fungus is consistent with that in Botrytis cinerea, except for the positions of double bonds in the rings of biosynthetic intermediates, suggesting that the pathway is common among ABA-producing fungi.  相似文献   

20.
目的:筛选具有拮抗植物病原真菌可可球二孢菌活性的放线菌.方法:选择高氏一号培养基分离放线菌,以可可球二孢菌为指示菌进行抑菌活性筛选,通过形态学特征、生理生化特征、培养特征以及16S rRNA基因序列分析等研究对筛选得到的高活性菌株进行菌种鉴定.结果:从南方红豆杉根际土壤中筛选得到一株高活性菌株KLBMP 2284,16S rRNA基因序列比对结果显示其与弗吉尼亚链霉菌(Streptomyces virginiae)相似性98.963%,发酵液稀释300倍后抑制率为41.64%.结论:KLBMP 2284为弗吉尼亚链霉菌的一个菌株.  相似文献   

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