RESUMEN
Fusarium proliferatum is a member of the Fusarium fujikuroi species complex (FFSC) involved in the maize ear rot together with Fusarium verticillioides, which is a very closely related species. Recently, different studies have detected natural fumonisin contamination in wheat kernels and most of them have shown that the main species isolated was F. proliferatum. Fusarium strains obtained from freshly harvested durum wheat samples (2008 to 2011 harvest seasons) from Argentina were characterized through a phylogenetic analysis based on translation elongation factor-1 alpha (EF-1α) and calmodulin (CaM) genes, determination of mating type alleles, and evaluation of fumonisin production capability. The strains were identified as F. proliferatum (72%), F. verticillioides (24%) and other Fusarium species. The ratio of mating type alleles (MAT-1 and MAT-2) obtained for both main populations suggests possible occurrence of sexual reproduction in the wheat fields, although this seems more frequent in F. proliferatum. Phylogenetic analysis revealed greater nucleotide variability in F. proliferatum strains than in F. verticillioides, however this was not related to origin, host or harvest year. The fumonisin-producing ability was detected in 92% of the strains isolated from durum wheat grains. These results indicate that F. proliferatum and F. verticillioides, among the fumonisin producing species, frequently contaminate durum wheat grains in Argentina, presenting a high risk for human and animal health.
Asunto(s)
Fumonisinas/metabolismo , Fusarium/genética , Genes Fúngicos/genética , Variación Genética , Triticum/microbiología , Argentina , Calmodulina/genética , Fumonisinas/análisis , Fusarium/química , Fusarium/clasificación , Fusarium/aislamiento & purificación , Genes del Tipo Sexual de los Hongos/genética , Factor 1 de Elongación Peptídica/genética , FilogeniaRESUMEN
Aspergillus section Nigri populations isolated from seven growing regions from Argentina were characterized by sequencing in order to identify species responsible for production of ochratoxin A (OTA) and fumonisins (FB(s)). Sequences of genes encoding calmodulin, ß-tubulin, the second largest subunit of RNA polymerase II and translation elongation factor 1 alpha were analysed. The phylogenetic analysis showed the presence of six lineages: A. carbonarius, A. tubingensis, A. niger, A. japonicus, A. homomorphus and A. foetidus grouped in four major clusters. The molecular tools used allowed the identification for the first time of A. homomorphus from vineyards. OTA production confirmed the importance of A. carbonarius as the main ochratoxigenic species isolated and, to a variable degree, of A. niger and A. tubingensis, which were by far the most commonly occurring species on grapes in Argentina. The only strains able to produce OTA and fumonisins (B(2)-B(4)) belong to the A. niger cluster.
Asunto(s)
Aspergillus/metabolismo , Fumonisinas/metabolismo , Ocratoxinas/metabolismo , Argentina , Aspergillus/clasificación , Aspergillus/genética , Proteínas Bacterianas/química , Proteínas Bacterianas/genética , Proteínas Bacterianas/metabolismo , Fumonisinas/química , Ocratoxinas/química , Filogenia , Tubulina (Proteína)/genética , Tubulina (Proteína)/metabolismo , Vitis/microbiologíaRESUMEN
Philotheca myoporoides (DC.) M.J. Bayly (previously known as Eriostemon myoporoides), commonly called long-leaf waxflower and native to eastern Australia (Rutaceae family), is a hardy compact shrub or small tree occurring in subtropical to cool temperate regions. P. myoporoides is cultivated in Sicily (Italy) for its ornamental appeal. During April of 2010, a widespread wilting was observed on approximately 80% of 2,000 1-year-old, potted long-leaf waxflower plants grown in a commercial nursery near Catania (eastern Sicily, Italy). Internally, symptomatic plants had conspicuous vascular brown discoloration from the crown to the canopy. Diseased crown and stem tissues of 20 plants were surface disinfested for 30 s in 1% NaOCl, rinsed in sterile water, plated on potato dextrose agar (PDA) amended with 100 mg/liter of streptomycin sulfate, and incubated at 25°C. A Fusarium sp. was consistently isolated from affected plant tissues. Colonies with white or light purple aerial mycelia and violet pigmentation on the underside of the cultures developed after 9 days. On carnation leaf agar, 20 single-spore isolates produced microconidia on short monophialides, macroconidia that were three to five septate with a pedicellate base, and solitary and double-celled or aggregate chlamydospores. A PCR assay was conducted on one representative isolate (ITEM 13490) by analyzing sequences of the benA gene (coding ß-tubulin protein) and CaM gene (coding calmodulin protein) using the primers reported by O'Donnell et al. (1). The benA gene sequences of ITEM 13490 (GenBank No. FR828825) exhibited an identity of 100% to Fusarium oxysporum f. sp. radicis-lycopersici strain ATCC 52429 (GenBank No. DQ092480). CaM gene sequences of ITEM 13490 (GenBank No. FR828826) exhibited an identity of 99.6% to F. oxysporum strain ITEM 2367 (GenBank No. AJ560774). Morphological characteristics of the 20 isolates, as well as the PCR assay on a representative strain, identified the isolates associated with disease symptoms as F. oxysporum Schlechtend.:Fr. A pathogenicity test was performed by placing two 1-cm2 plugs of PDA from 9-day-old mycelial cultures near the crown on potted, healthy, 2-month-old cuttings of P. myoporoides. Thirty plants were inoculated with strain ITEM 13490 and the same number of plants served as noninoculated controls. All plants were enclosed for 4 days in plastic bags and placed in a growth chamber at 25 ± 1°C. Plants were then moved to a greenhouse where temperatures ranged from 23 to 27°C. First symptoms, which were identical to those observed in the nursery, developed on one plant 15 days after inoculation. Wilting was detected on all plants after 30 days. Control plants remained symptomless. F. oxysporum was successfully reisolated from symptomatic crown and stem tissues and identified as described above, fulfilling Koch's postulates. To our knowledge, this is the first report of F. oxysporum causing disease of P. myoporoides worldwide. Moreover, this pathogen was recently reported in the same nursery on Eremophila sp. (2), confirming the presence of Fusarium wilt as a potential threat to ornamental plant production in this area, and necessitates the innovation and development of disinfection methods for alveolar trays, greenhouses, and various propagation materials to reduce future disease outbreaks. References: (1) K. O'Donnell et al. Mycoscience 41:61, 2000. (2) G. Polizzi et al. Plant Dis 94:1509, 2010.
RESUMEN
In June 2010, a widespread damping-off was noticed in a commercial nursery in eastern Sicily on ~20,000 potted 2-month-old strawberry tree (Arbutus unedo L.) seedlings. More than 40% of the seedlings showed disease symptoms including brown lesions at the seedling crown above and below the soil line that expanded rapidly to girdle the stem. Stem lesions were followed by death of the entire seedling in a few days. Diseased stem and crown tissues of 20 seedlings were surface disinfested for 2 min in 1% NaOCl, rinsed in sterile water, plated on potato dextrose agar amended with 100 mg/liter of streptomycin sulfate, and incubated at 25°C in the dark. Fungal isolates with mycelial and morphological characteristics of Colletotrichum spp. were isolated from all seedlings. Fungal colonies were pale orange or gray without carmine pigments. On carnation leaf agar (CLA), single-spore isolates produced many orange masses of hyaline, aseptate conidia with a cylindrical to ellipsoidal shape, rounded apex, and 11 to 15 µm long and 3 to 4.5 µm wide (average 13.2 × 3.7 µm). The pointed conidia of 10 isolates were morphologically similar. DNA isolation was performed with the Wizard Magnetic DNA Purification Kit (Promega, Madison, WI) following the manufacturer's instructions with some modifications. A PCR assay was conducted on two representative isolates (ITEM 13492 and ITEM 13493) by analyzing sequences of gene benA (coding ß-tubulin protein) using the primers T1 and T10 reported by O'Donnell and Cigelnik (1). BenA gene sequence of ITEM 13492 exhibited an identity of 99.8% to C. simmondsii strain BRIP 4704 (GenBank No. GU183277), while BenA gene sequence of ITEM 13493 exhibited an identity of 100% to C. acutatum strain BRIP52695 (GenBank No. GU183314). The identification of these two species was made by comparing the internal transcribed spacer region and BenA sequences of these two strains with that deposited by Shivas and Tan (2). Morphological characteristics, as well as the PCR assay, identified the isolates as Colletotrichum acutatum J.H. Simmonds and C. simmondsii R.G. Shivas & Y. P. Tan (2,3). Pathogenicity tests were carried out on 2-month-old seedlings of strawberry tree grown on alveolar trays. Conidial suspensions of two isolates (ITEM 13492 and ITEM 13493) were obtained from 14-day-old single-spore colonies on CLA, then adjusted to 105 conidia per ml and sprayed on seedlings. Fifty seedlings for each isolate were used. The same number of seedlings was mock inoculated with sterile distilled water. All seedlings were enclosed for 4 days in plastic bags and placed in a growth chamber at 24 ± 1°C for 45 days. Identical symptoms to those observed in the nurseries appeared 30 days after inoculation, and after 45 days, 80% of the plants were dead. No difference in virulence between the two isolates was observed and no symptoms were detected on the control plants. C. acutatum and C. simmondsii were successfully reisolated from all symptomatic tissues and identified as previously described, completing Koch's postulates. To our knowledge, this is the first report in the world of C. acutatum and C. simmondsii on strawberry tree. This suggests that Colletotrichum spp. may be important pathogens of young seedlings of strawberry tree in nurseries. References: (1) K. O'Donnell and E. Cigelnik. Mol. Phylo. Evol. 7:103, 1997. (2) R. G. Shivas and Y. P. Tan. Fungal Divers. 39:111, 2009. (3) B. C. Sutton. Page 523 in: The Coelomycetes. Commonwealth Mycological Institute, Kew, Surrey, England, 1980.
RESUMEN
Paper flower (Bougainvillea glabra Choisy), native to Brazil, is the most widely and intensively cultivated species of bougainvillea as a potted plant in Sicily (Italy). During 2008 and 2009, a wilting of vegetatively produced B. glabra cv. Sanderiana was observed in several nurseries in eastern Sicily (Catania and Messina provinces). Disease incidence was higher (~10 to 30%) in the tree-shaped potted plants (standards). Occasionally, wilting was detected on plants that were not tree shaped. Internally, symptomatic plants showed conspicuous vascular orange discoloration from the crown to the canopy. Diseased crown and stem tissues were surface disinfested for 30 s in 1% NaOCl, rinsed in sterile water, plated on potato dextrose agar (PDA) amended with 100 mg/liter of streptomycin sulfate, and incubated at 25°C. A Fusarium sp. was consistently isolated from affected plant tissue. Colonies with light purple or purple mycelia and violet reverse colony colors developed after 10 days. On carnation leaf agar, single-spore isolates produced microconidia in false heads on short monophialides, macroconidia that were 3-septate with a pedicellate base, and solitary and double-celled or aggregate chlamydospores. A PCR assay was conducted on two representative strains (DISTEF-BGS1 and DISTEF-BGS2) by analyzing sequences of the parzial translation elongation factor alpha gene (TEF-1α) and CaM gene (coding calmodulin protein). The primers used are previously used by O'Donnell et al. (1,2). Calmodulin sequences of BGS1 and BGS2 strains (GenBank Nos. FN645740 and FN645741, respectively) exhibited 99% homology with Fusarium oxysporum strain ITEM 2367 (GenBank No. AJ560774), and have homology of 99.6% between them. TEF-1 gene sequences of BGS1 (GenBank No. FN645739) exhibited an identity of 100% to F. oxysporum f. sp. lycopersici MUCL 22544 GenBank No. EF056785.1) and TEF-1α gene sequences of BGS2 (GenBank No. FN655742) exhibited an identity of 100% to F. oxysporum strain NRRL 45954 (GenBank No. FJ985431.1), whereas the homology between the two strains is 98.5%. Both PCR approaches established the identity of the isolates to the F. oxysporum Schlechtend:Fr (1,2). Pathogenicity tests were performed by placing 1-cm2 plugs of PDA from 10-day-old mycelial cultures near the crown on 40 potted, healthy, 6-month-old cuttings of paper flower. Twenty plants for each isolate were used. The same number of plants served as noninoculated controls. All plants were enclosed for 5 days in plastic bags and placed in a growth chamber at 24 ± 1°C. Plants were then moved to a greenhouse where temperatures ranged from 24 to 26°C. Symptoms identical to those observed in nurseries developed 1 month after inoculation with both strains. Crown and stem orange discoloration was detected in all inoculated plants after 2 months. Control plants remained symptomless. F. oxysporum was consistently reisolated from symptomatic tissues and identified as previously described. To our knowledge, F. oxysporum was previously reported on paper flower in Ghana (3). However, this is the first demonstration of the pathogenicity of F. oxysporum on paper flower and it is the first report in Europe of the disease. The presence of Fusarium wilt in Sicily is a potential threat to paper flower production in nurseries. References: (1) K. O'Donnell et al. Proc. Natl. Acad. Sci. USA 95:2044, 1998. (2) K. O'Donnell et al. Mycoscience 41:61, 2000. (3) P. Spaulding. USDA Agric. Handb. 197:1, 1961.
RESUMEN
Single-stranded conformational polymorphism (SSCP) analysis for genetic diversity studies has been widely applied to detect indirectly sequence differences up to a single base in amplified DNA fragments of the same length, representing an alternative to gene sequencing. In this study SSCP analysis was used to detect sequence variations contained in an about 180-bp region of the calmodulin gene in order to identify Aspergillus section Nigri species. The method described shows that fluorescence-based SSCP analysis by capillary electrophoresis is cheaper and faster than direct sequencing, and suitable for computer-assisted analyses allowing discrimination between the Aspergillus species belonging to the Nigri section: A. aculeatus, Aspergillus 'atypic uniseriate', A. brasiliensis, A. carbonarius, A. ellipticus, A. foetidus, A. heteromorphus, A. ibericus, A. japonicus, A. niger, and A. tubingensis.
Asunto(s)
Aspergillus/aislamiento & purificación , Calmodulina/metabolismo , ADN de Hongos/análisis , Reacción en Cadena de la Polimerasa/métodos , Polimorfismo Conformacional Retorcido-Simple/genética , Aspergillus/clasificación , Aspergillus/genética , Calmodulina/genética , ADN de Hongos/genética , Microbiología de Alimentos , Especificidad de la EspecieRESUMEN
Aspergillus niger and A. tubingensis, species belonging to section Nigri, are commonly found in plant products and processed food, such as grapes, cereals, coffee, and derived products. These two species are very difficult to differentiate by classical morphological criteria and some isolates are known to produce ochratoxin A. The exact identification of these two species is very important to avoid the overestimation of toxicological contamination and related risks. A polymerase chain reaction (PCR)-based identification and detection assay was developed as a tool to identify A. niger and A. tubingensis, using molecular differences obtained by sequencing the calmodulin gene. Two pairs of species-specific primers were designed and empirically evaluated for PCR identification of A. niger and A. tubingensis. Species-specific PCR products generated by each primer set were 505 bp (A. tubingensis) and 245 bp (A. niger) in length, which could be potentially useful for a multiplex PCR assay. The sensitivity of this assay was about 10 pg DNA in a 25-microl PCR reaction volume, using pure total DNA of the two species. The method described in this study represents a rapid and reliable procedure to assess the presence in food products of two ochratoxigenic species of section Nigri.
Asunto(s)
Aspergillus/clasificación , Calmodulina/metabolismo , ADN de Hongos/análisis , Reacción en Cadena de la Polimerasa/métodos , Aspergillus/genética , Aspergillus/aislamiento & purificación , Aspergillus niger/genética , Aspergillus niger/aislamiento & purificación , Calmodulina/genética , ADN de Hongos/genética , Microbiología de Alimentos , Especificidad de la EspecieRESUMEN
Aspergillus carbonarius is the main species responsible for the production of ochratoxin A (OTA) in wine grapes. To monitor and quantify A. carbonarious in grapes, a quantitative real-time PCR assay was developed as a possible tool for predicting the potential ochratoxigenic risk. DNA extraction from grape berries was performed by using conventional extraction and clean up through EZNA Hi-bond spin columns. A TaqMan probe was used to quantify A. carbonarius genomic DNA in grape berries samples. An exogenous internal positive control was used to overcome DNA recovery losses due to matrix inhibition. The quantification of fungal genomic DNA in naturally contaminated grape was performed using the TaqMan signal versus spectrophotometrically measured DNA quantities (Log10) calibration curve with a linearity range from 50 to 5 x 10(-4) ng of DNA. A positive correlation (R2=0.92) was found between A. carbonarious DNA content and OTA concentration in naturally contaminated grape samples. This is the first application of TaqMan real-time PCR for identifying and quantifying A. carbonarius genomic DNA occurring in grapes. The rapid DNA extraction method for grapes, together with the commercial availability of reagents and instrumentation, allows to perform a remarkable number of reproducible assays (96-well format) in less than 4 h.
Asunto(s)
Aspergillus/aislamiento & purificación , ADN de Hongos/química , Reacción en Cadena de la Polimerasa/métodos , Vitis/microbiología , Aspergillus/metabolismo , Seguridad de Productos para el Consumidor , ADN de Hongos/genética , Contaminación de Alimentos/análisis , Microbiología de Alimentos , Humanos , Ocratoxinas/análisis , Ocratoxinas/biosíntesis , Especificidad de la Especie , Vitis/químicaRESUMEN
The genus Fusarium includes several species that produce trichothecenes. We analyzed DNA sequences from a variable region at the 5' end of the large nuclear ribosomal DNA (rDNA) (28S) to determine the genetic relatedness of trichothecene-producing Fusarium species. All trichothecene-producing strains clustered together, and two monophyletic groups were resolved. The first clade included strains of F. acuminatum, F. sambucinum, F. tumidum, F. compactum, F. camptoceras (red pigment), F. sporotrichioides, and F. venenatum, which produced type A trichothecenes (T-2 toxin, HT-2 toxin, neosolaniol, and diacetoxyscirpenol). The second clade consisted of strains of F. crookwellense, F. culmorum, and F. graminearum, which produced type B trichothecenes (fusarenone-X, nivalenol, and deoxynivalenol). The phylogenetic placement of the species based on rDNA correlated better with toxic secondary metabolite data rather than with the current classification system based on morphology.
Asunto(s)
ADN de Hongos/análisis , Fusarium/clasificación , Fusarium/genética , ARN Ribosómico 28S/genética , Fusarium/metabolismo , Datos de Secuencia Molecular , Filogenia , Análisis de Secuencia de ADN , Homología de Secuencia de Ácido Nucleico , Tricotecenos/metabolismoRESUMEN
The toxicity of twenty-fourFusarium isolates was evaluated towards larvae ofGalleria mellonella by the antlfeedant activity of the autoclaved fungal culture incorporated into insect diet. Culturesof isolates belonging to F.sporotrichioldes, F. compactum andF. sambucinum, well known as capable to synthesize trichothecenes, showed high antifeedant activity (ca 60-70%); whereas controversial activity was showed byF. equiseti, F. proliferatum andF. solani cultures, and not significant activity was showed byF. oxysporum cultures. The G.mellonella larvae bioassay is suggested as a reliable sensitive Insectbioassay for screening fungal toxicity.
Asunto(s)
Síndrome de la Disfunción de Articulación Temporomandibular/rehabilitación , Adolescente , Adulto , Anciano , Oclusión Dental , Femenino , Estudios de Seguimiento , Humanos , Masculino , Manipulación Ortopédica , Masaje , Masticación , Persona de Mediana Edad , Recurrencia , Síndrome de la Disfunción de Articulación Temporomandibular/etiologíaRESUMEN
Ewing's sarcoma of the jaw is a rare primary malignant bone tumor. Three cases, two in the mandible and one in the maxilla, are presented, together with complete histologic, radiographic, and clinical evaluations. While the prognosis for patients with this lesion remains poor, an increased rate of survival is now associated with multiple-drug chemotherapeutic regimens.
Asunto(s)
Neoplasias Mandibulares/patología , Neoplasias Maxilares/patología , Sarcoma de Ewing/patología , Niño , Preescolar , Terapia Combinada , Femenino , Estudios de Seguimiento , Humanos , Masculino , Neoplasias Mandibulares/terapia , Neoplasias Maxilares/terapia , Sarcoma de Ewing/terapiaAsunto(s)
Neoplasias Maxilares/patología , Tumores Odontogénicos/patología , Ameloblastoma/diagnóstico , Niño , Diagnóstico Diferencial , Humanos , Masculino , Neoplasias Maxilares/diagnóstico por imagen , Neoplasias Maxilares/cirugía , Tumores Odontogénicos/diagnóstico por imagen , Tumores Odontogénicos/cirugía , Radiografía , Terminología como AsuntoRESUMEN
The incidence of pathological neck nodes metastases in a group of 60 patients with a diagnosis of oral squamous carcinoma is reviewed. Risk factors are a size of primary more than 4 cm and tumors of the anterior two-third of the tongue. Carcinomas of oral tongue, also of a size less than 4 cm (T1,T2), have a high incidence of subclinical metastases.
Asunto(s)
Carcinoma/patología , Ganglios Linfáticos/patología , Neoplasias de la Boca/patología , Femenino , Humanos , Metástasis Linfática , Masculino , Persona de Mediana Edad , Cuello , Estadificación de Neoplasias , RiesgoRESUMEN
The author presents 44 cases of mixed tumours of the parotid gland, operated on by simple enucleation and not radical removal of the gland, which most authors maintain must always be carried out. There were 6 recurrences (13.6 percent), and the last appeared in 1965. He maintains that simple enucleation is justified. It is reasonable to hope for a further decrease in the number of recurrences with future improvement in surgical techniques.