RESUMEN

BACKGROUND: Besides the anticoccidial drug resistance problem, increasing consumer concerns about food safety and residues have propelled the quest for alternative prevention and control strategies amongst which phytotherapy has gained appeal due to a renewed interest in natural medicine. OBJECTIVE: The objective was in vivo screening of four phytochemicals/extracts and a fungal immunomodulatory protein (FIP) against an Eimeria acervulina infection in broilers. ANIMALS AND METHODS: Four phytochemicals/extracts (extract from Echinacea purpurea, betaine (Betain™), curcumin, carvacrol (two different doses)), and a recombinant FIP from Ganoderma lucidum cloned and expressed in Escherichia coli were investigated for their anticoccidial potential. The experiment was conducted in a battery cage trial with 54 cages of eight birds each. Broilers infected with E. acervulina (a low and high infection dose of 10(4) and 10(5) sporulated oocysts, respectively) and treated with the phytochemicals/extracts or the FIP were compared with broilers treated with the anticoccidial salinomycin sodium (Sacox®) and with an untreated uninfected and an untreated infected control group. Coccidiosis lesion scores, body weight gains and oocyst shedding were used as parameters. RESULTS: The results showed a coccidiosis infection dose effect on the mean coccidiosis lesion scores. The phytochemicals/extracts and the FIP failed to reduce coccidiosis lesion scores and oocyst shedding, while salinomycin efficiently controlled the E. acervulina infection and enabled significantly higher body weight gains. CONCLUSION: In conclusion, the selected phytochemicals/extracts and the FIP did not reduce the lesions of an experimentally induced E. acervulina infection.

Asunto(s)

Pollos , Coccidiosis/veterinaria , Coccidiostáticos/farmacología , Eimeria/efectos de los fármacos , Proteínas Fúngicas/farmacología , Extractos Vegetales/farmacología , Enfermedades de las Aves de Corral/tratamiento farmacológico , Animales , Betaína/administración & dosificación , Betaína/farmacología , Coccidiosis/tratamiento farmacológico , Coccidiosis/parasitología , Coccidiostáticos/administración & dosificación , Curcumina/administración & dosificación , Curcumina/farmacología , Cimenos , Relación Dosis-Respuesta a Droga , Echinacea/química , Escherichia coli/genética , Proteínas Fúngicas/administración & dosificación , Proteínas Fúngicas/genética , Factores Inmunológicos/administración & dosificación , Factores Inmunológicos/farmacología , Masculino , Monoterpenos/administración & dosificación , Monoterpenos/farmacología , Extractos Vegetales/administración & dosificación , Enfermedades de las Aves de Corral/parasitología , Piranos/administración & dosificación , Piranos/farmacología , Proteínas Recombinantes/administración & dosificación , Proteínas Recombinantes/genética , Proteínas Recombinantes/farmacología , Reishi/química , Reishi/genética , Organismos Libres de Patógenos Específicos

RESUMEN

Five phytochemicals/extracts (an extract from Echinacea purpurea, a ß-glucan-rich extract from Shiitake, betaine [Betain™], curcumin from Curcuma longa [turmeric] powder, carvacrol and also a recombinant fungal immunomodulatory protein [FIP] from Ganoderma lucidum) cloned and expressed in Escherichia coli were investigated for their anticolibacillosis potential in three chicken experiments, which were conducted in floor pens. Birds that were inoculated with E. coli intratracheally were treated with the phytochemicals/extracts or the FIP and compared with doxycycline-medicated and non-medicated infected broilers. Non-medicated and non-infected birds were used as negative controls. Mortality, colibacillosis lesions and body weight gains were used as parameters. Considering the sum of dead birds and chickens with generalized colibacillosis per group, there was no significant difference between the positive control groups and birds treated with phytochemicals/extracts or the FIP. In contrast, doxycycline-treated birds showed significantly lower mortality and generalized colibacillosis. Moreover, none of the phytochemicals/extracts and the FIP improved recovery from colibacillosis lesions, while all doxycycline-treated broilers recovered completely. The negative control birds and doxycycline-treated groups consistently showed the highest weight gains. Pulsed-field gel electrophoresis of reisolates showed that they were genetically indistinguishable from the inoculation strain. In conclusion, none of the tested phytochemicals/extracts and the FIP significantly reduced the E. coli-induced mortality and generalized colibacillosis, and nor did they improve recovery from colibacillosis lesions.

Asunto(s)

Antibacterianos/farmacología , Pollos , Infecciones por Escherichia coli/veterinaria , Extractos Vegetales/farmacología , Enfermedades de las Aves de Corral/tratamiento farmacológico , Enfermedades de las Aves de Corral/microbiología , Animales , Betaína/farmacología , Peso Corporal , Curcuma/química , Curcumina/farmacología , Cimenos , Doxiciclina/farmacología , Echinacea/química , Electroforesis en Gel de Campo Pulsado/veterinaria , Escherichia coli , Infecciones por Escherichia coli/tratamiento farmacológico , Infecciones por Escherichia coli/mortalidad , Infecciones por Escherichia coli/patología , Monoterpenos/farmacología , Enfermedades de las Aves de Corral/mortalidad , Enfermedades de las Aves de Corral/patología , Reishi/química , Hongos Shiitake/química , Estadísticas no Paramétricas

RESUMEN

With the full genome sequence of Agaricus bisporus available, it was possible to investigate the genes involved in the melanin biosynthesis pathway of button mushrooms. Based on different BLAST and alignments, genes were identified in the genome which are postulated to be involved in this pathway. Seven housekeeping genes were tested of which 18S rRNA was the only housekeeping gene that was stably expressed in various tissues of different developmental stages. Gene expression was determined for most gene homologs (26 genes) involved in the melanin pathway. Of the analysed genes, those encoding polyphenol oxidase (PPO), the PPO co-factor L-chain (unique for A. bisporus), and a putative transcription factor (photoregulator B) were among the highest expressed in skin tissue. An in depth look was taken at the clustering of several PPO genes and the PPO co-factor gene on chromosome 5, which showed that almost 25% of the protein encoding genes in this cluster have a conserved NACHT and WD40 domain or a P-loop nucleoside triphosphate hydrolase. This article will be the start for an in depth study of the melanin pathway and its role in quality losses of this economically important product.

Asunto(s)

Agaricus/genética , Vías Biosintéticas/genética , Melaninas/biosíntesis , Secuencias de Aminoácidos , Biología Computacional , Secuencia Conservada , Perfilación de la Expresión Génica , Familia de Multigenes , Estructura Terciaria de Proteína , Alineación de Secuencia

RESUMEN

The tomato resistance gene I-2 is one of at least six members of a gene family that are expressed at low levels in the roots, stems and leaves of young tomato plants. Plants transformed with constructs containing a functional I-2 promoter fused to the beta-glucuronidase (GUS) reporter gene were used in detailed expression studies. Highest GUS activity was found in stems of young tomato plants. Histochemical analysis revealed that the I-2 promoter drives expression of the reporter gene in vascular tissue of fruits, leaves, stems and mature roots. In younger roots, expression was most abundant at the base of lateral root primordia. Microscopical analysis of young tomato plants revealed expression in tissue surrounding the xylem vessels. We show that in resistant plants, fungal growth into this region of the vascular tissue is prevented, suggesting a correlation with the I-2-mediated resistance response.

Asunto(s)

Fusarium/patogenicidad , Familia de Multigenes , Regiones Promotoras Genéticas , Solanum lycopersicum/genética , Solanum lycopersicum/microbiología , Secuencia de Bases , Genes de Plantas , Genes Reporteros , Glucuronidasa/genética , Inmunidad Innata/genética , Datos de Secuencia Molecular , Plantas Modificadas Genéticamente , Proteínas Recombinantes/biosíntesis , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Alineación de Secuencia , Homología de Secuencia de Ácido Nucleico

RESUMEN

A novel family of short interspersed nuclear elements (SINEs) has been identified in Fusarium oxysporum. This family has been called Foxy. The feature that makes Foxy unique among SINEs is the presence of 5' terminal tetranucleotide repeats. Both the number and the sequence of these repeats vary between individual members of the family. The genome of F. oxysporum f. sp. lycopersici contains at least 160 copies of Foxy. In a mutant obtained upon gamma irradiation of a wild-type isolate, 13 new Foxy insertions were identified. These observations, together with the occurrence of many Foxy-specific polymorphisms between isolates within one vegetative incompatibility group and the presence of Foxy-specific transcripts in the fungus, indicate that Foxy is currently active and may contribute to the genetic variability of F. oxysporum. Since we have not been able to detect Foxy sequences by PCR analyses in other fungi, this novel family of SINEs seems to be confined to Fusarium species.

Asunto(s)

Fusarium/genética , Elementos de Nucleótido Esparcido Corto/genética , Secuencia de Bases , Northern Blotting , Genes Fúngicos , Genoma Fúngico , Datos de Secuencia Molecular , Conformación de Ácido Nucleico , Polimorfismo de Longitud del Fragmento de Restricción , Secuencias Repetitivas de Ácidos Nucleicos , Homología de Secuencia de Ácido Nucleico

RESUMEN

ABSTRACT The tomato Fusarium resistance gene I-2 confers resistance to F. oxy-sporum f. sp. lycopersici race 2, which expresses the corresponding aviru-lence gene avrI-2. To elucidate the molecular basis of this gene-for-gene interaction, we initiated a search for the avrI-2 gene. Gamma irradiation mutagenesis, using (137)Cs, was performed to generate an avrI-2 mutant of F. oxysporum f. sp. lycopersici. To this end, a race 2 isolate was first transformed with a phleomycine resistance gene and a GUS marker gene in order to distinguish mutants from contaminating isolates. A total of 21,712 mutagenized colonies was tested for loss of avirulence on I-2-containing tomato seedlings. One mutant was selected that showed the expected loss of avirulence but, surprisingly, also showed reduced pathogenicity toward susceptible tomato plants. DNA analysis was subsequently used to visualize genomic changes in the mutant. Southern analysis on contour-clamped homogeneous electrophoretic field blots demonstrated a translocation of a 3.75-Mb chromosome in the mutant. Random amplified polymorphic DNA and amplified fragment length polymorphism analysis identified at least nine polymorphisms between the wild-type and mutant isolates. Most of these polymorphisms appeared as extra fragments in the mutant and contained repetitive DNA sequences.

RESUMEN

ABSTRACT A collection of race 1 and race 2 isolates of Fusarium oxysporum f. sp. lycopersici was screened for vegetative compatibility and characterized by random amplified polymorphic DNA (RAPD) analysis to establish the identity and genetic diversity of the isolates. Comparison of RAPD profiles revealed two main groups that coincide with vegetative compatibility groups (VCGs). In addition, several single-member VCGs were identified that could not be grouped in one of the two main RAPD clusters. This suggests that F. oxysporum f. sp. lycopersici is a polyphyletic taxon. To assign avirulence genotypes to race 1 isolates, they were tested for their virulence on a small set of tomato lines (Lycopersicon esculentum), including line OT364. This line was selected because it shows resistance to race 2 isolates but, unlike most other race 2-resistant lines, susceptibility to race 1 isolates. To exclude the influence of other components than those related to the race-specific resistance response, we tested the virulence of race 1 isolates on a susceptible tomato that has become race 2 resistant by introduction of an I-2 transgene. The results show that both line OT364 and the transgenic line were significantly affected by four race 1 isolates, but not by seven other race 1 isolates nor by any race 2 isolates. This allowed a subdivision of race 1 isolates based on the presence or absence of an avirulence gene corresponding to the I-2 resistance gene. The data presented here support a gene-for-gene relationship for the interaction between F. oxysporum f. sp. lycopersici and its host tomato.