RESUMEN

The genus Allocreadium is a group of digenetic trematodes whose adult representatives mainly parasitize the intestines of freshwater fishes. The aim of this research is to reconstruct the phylogeny of four Palearctic species of this genus, Allocreadium dogieli, Allocreadium isoporum, Allocreadium papilligerum, and Allocreadium sp. ex Oreoleuciscus potanini from Mongolia. The DNA sequences of the 28S rRNA gene and the rDNA ITS2 region were obtained and then analyzed for phylogenetic inference. The analysis is complemented with the morphological descriptions for all four species. Phylogenetic analyses show that the newly obtained isolate of A. isoporum appeared to be genetically similar to previously obtained isolates of A. isoporum. Allocreadium dogieli probably belongs to the same evolutionary lineage of Allocreadium as A. crassum, while A. papilligerum to the same evolutionary lineage as Alocreadium transversale ex Cobitis taenia from Lithuania, but the detailed species composition of these lineages requires further elucidation. Allocreadium sp. was genetically close to Allocreadium sp. ex P. phoxinus from Primorski Krai, Russia, and a group of these Allocreadium had a sister relationship with Allocreadium khankaiensis. Our findings contradict some recent hypotheses about the phylogeography of Allocreadium spp.

Asunto(s)

Cipriniformes , Trematodos , Infecciones por Trematodos , Animales , Filogenia , ADN Ribosómico/genética , Secuencia de Bases , ARN Ribosómico 28S/genética , Infecciones por Trematodos/veterinaria , Infecciones por Trematodos/genética

RESUMEN

New data on the effect of colloidal silicon nanoparticles on the content of nutrients and photosynthetic pigments in tomato plants invaded by root-knot nematode Meloidogyne incognita are presented. Foliar treatment of plants with colloidal solutions of silicon nanoparticles at concentrations of 0.5 and 1.0 µg/mL revealed an increase in the content of photosynthetic pigments and a number of biogenic elements (P, Mg, K, S, and Fe) in tomato leaves, indicating an improvement in the physiological state of the invaded plants. The stimulating effect of nanosilicon on the development and growth of plants and the inhibiting effect on the susceptibility of plants by nematodes and the morpho-physiological parameters of the parasite is shown.

Asunto(s)

Nanopartículas/administración & dosificación , Pigmentos Biológicos/metabolismo , Enfermedades de las Plantas/prevención & control , Silicio/farmacología , Solanum lycopersicum/efectos de los fármacos , Solanum lycopersicum/parasitología , Oligoelementos/metabolismo , Animales , Solanum lycopersicum/metabolismo , Nanopartículas/química , Fotosíntesis/efectos de los fármacos , Enfermedades de las Plantas/parasitología , Raíces de Plantas/efectos de los fármacos , Raíces de Plantas/parasitología , Silicio/química , Tylenchoidea/aislamiento & purificación

RESUMEN

We investigated the mechanisms of action of selenium nanoparticles obtained by laser ablation for their use as an abiogenic elicitor of tomato resistance to parasitic nematodes. Selenium nanoparticles induced systemic resistance of tomatoes to the root-knot nematode, stimulated plant growth and development, was involved in the PR-6 gene expression in the roots and leaves of plants subjected to invasion, and increased the activity of proteinase inhibitors (markers of systemic resistance of plants to infection). Exogenous treatment of plants with solutions of selenium nanoparticles reduced the invasion of plants by affecting the morphological and physiological parameters of the parasites in the roots.

Asunto(s)

Resistencia a la Enfermedad/efectos de los fármacos , Nanopartículas , Raíces de Plantas/efectos de los fármacos , Selenio/farmacología , Solanum lycopersicum/efectos de los fármacos , Infecciones por Nematodos/tratamiento farmacológico , Péptido Hidrolasas/efectos de los fármacos , Péptido Hidrolasas/metabolismo

RESUMEN

The trematode Postlepidapedon opisthobifurcatum (Zdzitowiecki, 1990) is a common intestinal parasite of the gadiform fishes of the Southern Ocean. In this work, we supplement the description of the species with the anatomy of the terminal part of the reproductive system and with molecular data. The male terminal genitalia are characterised by the presence of the external seminal vesicle and cirrus-sac. The external seminal vesicle is surrounded by aciniform groups of outer prostatic cells. Groups of outer prostatic cells and proximal parts of their ducts are associated with a thin-walled membrane that is connected to the proximal edge of the сirrus-sac. The cirrus-sac is claviform, with a long proximal part accommodating the tubular, thin-walled internal seminal vesicle and ducts of outer prostatic cells. The female terminal genitalia are represented by a thick-walled metraterm, which is surrounded by aciniform groups of glandular cells. Phylogenetic analysis based on 28S rDNA partial sequences data placed P. opisthobifurcatum into the monophyletic group Lepidapedidae, including the species Myzoxenus insolens (Crowcroft, 1945), Intusatrium robustum Durio et Manter, 1968, and Postlepidapedon uberis Bray, Cribb et Barker, 1997. However, we were unable to detect direct phylogenetic connections between P. opisthobifurcatum and P. uberis.

Asunto(s)

Recombinación Homóloga , Mitosis , Proteínas de Schizosaccharomyces pombe/química , Proteínas de Schizosaccharomyces pombe/metabolismo , Schizosaccharomyces/citología , Schizosaccharomyces/genética , Secuencias de Aminoácidos , Schizosaccharomyces/metabolismo

RESUMEN

The dynamics of expression of two homologous genes Mi-1.1 and Mi-1.2 in the roots of resistant and susceptible tomato plants in non-invasion conditions and during invasion with the root-knot nematode M. incognita was studied. Nematode invasion was accompanied by a significant increase in the expression level of both genes; however, the accumulation of transcripts at the early stages of nematode invasion in the penetration of nematode juveniles to the roots was observed only in plants that contained the Mi-1.2 gene, which explains the resistance of tomatoes to this root-knot nematode, caused by only this gene. We reveal a change in the Mi-1 gene activity under exogenous salicylic acid treatment, which contributed to the formation of induced resistance to root-knot nematode in the susceptible plants.

Asunto(s)

Genes de Plantas , Enfermedades de las Plantas/terapia , Proteínas de Plantas/metabolismo , Ácido Salicílico/farmacología , Solanum lycopersicum/genética , Solanum lycopersicum/parasitología , Tylenchoidea/patogenicidad , Animales , Antinematodos/farmacología , Resistencia a la Enfermedad , Expresión Génica/efectos de los fármacos , Enfermedades de las Plantas/genética , Enfermedades de las Plantas/parasitología , Proteínas de Plantas/genética , Raíces de Plantas/efectos de los fármacos , Raíces de Plantas/metabolismo , Raíces de Plantas/parasitología , Factores de Tiempo

Asunto(s)

Anticuerpos Antibacterianos/sangre , Inmunización , Toxina Shiga II/genética , Toxina Shiga II/inmunología , Secuencia de Aminoácidos , Animales , Supervivencia Celular/efectos de los fármacos , Supervivencia Celular/fisiología , Chlorocebus aethiops , Relación Dosis-Respuesta a Droga , Escherichia coli Enterotoxigénica , Infecciones por Escherichia coli/prevención & control , Violeta de Genciana , Conejos , Toxina Shiga II/toxicidad , Células Vero

RESUMEN

Repair of double-stranded DNA breaks that occur spontaneously or under the influence of external factors, are critical for cell survival. Evolutionarily conserved mechanism for error-free recombinational repair plays a major role in maintaining genome integrity. Repair pathway is conservative and has a number of similarities in lower eukaryotes and vertebrates. This review examines the current state of studying the mechanism of recombinational repair double-stranded DNA breaks in the fission yeast Schizosaccharomyces pombe, notes the differences of this type of repair in Saccharomyces cerevisiae and higher eukaryotes.

Asunto(s)

ADN/metabolismo , Reparación del ADN por Recombinación/genética , Proteínas de Schizosaccharomyces pombe/metabolismo , Schizosaccharomyces/metabolismo , Animales , Evolución Biológica , Supervivencia Celular/genética , ADN/química , ADN/genética , Roturas del ADN de Doble Cadena , Humanos , Mapeo de Interacción de Proteínas , Schizosaccharomyces/genética , Proteínas de Schizosaccharomyces pombe/química , Proteínas de Schizosaccharomyces pombe/genética , Transducción de Señal/genética

Asunto(s)

Proteínas de Saccharomyces cerevisiae/metabolismo , Saccharomyces cerevisiae/metabolismo , Secuencia de Bases , Sitios de Unión , Cartilla de ADN , Mutagénesis Sitio-Dirigida , Unión Proteica , Proteínas Recombinantes/metabolismo

RESUMEN

Repair of DNA double-stranded breaks caused by ionizing radiation or cellular metabolization, homologous recombination, is an evolutionary conserved process controlled by RAD52 group genes. Genes of recombinational repair also play a leading role in the response to DNA damage caused by UV light. Cells with deletion in gene dds20 of recombinational repair were shown to manifest hypersensitivity to the action of UV light at lowered incubation temperature. Epistatic analysis revealed that dds20+ is not a member of the NER and UVER gene groups responsible for the repair of DNA damage induced by UV light. The Dds protein has functions in the Cds1-independent mechanism of UV damage tolerance of DNA.

Asunto(s)

Daño del ADN , Reparación del ADN/genética , Proteínas de Unión al ADN/fisiología , Tolerancia a Radiación/genética , Proteínas de Schizosaccharomyces pombe/fisiología , Schizosaccharomyces/genética , Schizosaccharomyces/efectos de la radiación , Quinasa de Punto de Control 2 , Roturas del ADN de Doble Cadena , Proteínas de Unión al ADN/genética , Proteínas Serina-Treonina Quinasas/genética , Proteínas Serina-Treonina Quinasas/fisiología , Proteínas de Schizosaccharomyces pombe/genética , Rayos Ultravioleta

RESUMEN

The discovery of three Rad51 paralogs in Saccharomyces cerevisiae (Rad55, Rad57, and Dmc1), four in Schizosaccharomyces pombe (Rhp55, Rhp57, Rlp 1, and Dmc 1), and six in human (Rad51 B, Rad51 C, Rad51 D, Xrcc2, Xrcc3, and Dmcl) indicate the functional diversity and specialization of RecA-like proteins in the line from the lower to higher organisms. This paper reports characterization of a number of mitotic and meiotic phenotypes of the cells mutant in rlpl gene, encoding a paralog of Rad5 1, in fission yeasts. No evident role of Rlp I protein in the repair of spontaneous lesions emerging during mating type switching was found. Rlpl does not interact physically with Dmcl. An elevated expression of rhp51 has a dominant negative effect on the cell survivability of rlpl mutant exposed to a DNA-damaging agent. We assume that Rlp 1 acts at the stages of recombination connected with disassembling of the nucleoprotein filament formed by Rhp51 protein.

Asunto(s)

Recombinasa Rad51/metabolismo , Rec A Recombinasas/metabolismo , Recombinasas/metabolismo , Proteínas de Schizosaccharomyces pombe/metabolismo , Schizosaccharomyces/metabolismo , Daño del ADN , Reparación del ADN , Meiosis , Metilmetanosulfonato/farmacología , Mutágenos/farmacología , Mutación , Isoformas de Proteínas/genética , Isoformas de Proteínas/metabolismo , Recombinasa Rad51/genética , Rec A Recombinasas/genética , Recombinasas/genética , Recombinación Genética , Schizosaccharomyces/genética , Proteínas de Schizosaccharomyces pombe/genética

RESUMEN

DNA double-strand breaks may occur both under the action of various exogenous factors and in the course of cell metabolism processes, in particular, upon mating type switching in yeast. Genes belonging to the epistatic group RAD52 are known to repair such DNA damage. Molecular defects in mating type switching occurring after the deletion of gene rhp55+ encoding the paralog of recombinational protein Rhp51, which is a functional homolog of Escherichia coli RecA, were studied in fission yeast. Analysis of stable nonswitching segregants in h90 rhp55 mutants with unchanged configuration of the mating type switching locus but with a drastically decreased level of double-strand DNA break formation at the mat1 :1 locus demonstrated changes in DNA sequences within the region responsible for the generation of the breaks. These changes might have resulted from incorrect gene conversion upon repair of double-strand DNA breaks in Schizosaccharomyces pombe rhp55 mutants.

Asunto(s)

Conversión Génica , Eliminación de Gen , Genes Fúngicos , Schizosaccharomyces/genética , Secuencia de Bases , Reparación del ADN , ADN de Hongos/genética , Datos de Secuencia Molecular , Recombinasa Rad51/genética

RESUMEN

DNA double-strand breaks (DSBs) occur after exposing cells to ionizing radiation or under the action of various antitumor antibiotics. They can be also generated in the course cell processes, such as meiosis and mating type switching in yeast. The most preferential mechanism for the correction of DNA DSB in yeasts is recombinational repair controlled by RAD52 group genes. The role of recombinational repair in mating type switching of fission yeast cells was examined on the example of genes of this group, rhp51+ and rhp51+. We constructed homothallic strains of genotypes h90 rhp51 and h90 rhp55, and found that mutant cells yielded colonies with the mottled phenotype. In addition, h90 cells with deletions in these genes were shown to segregate heterothallic iodine-negative colonies h- and h+. The genome region, responsible for the switching process in these segregants, was analyzed by DNA hybridization. As shown in this analysis, h+ segregants had the h+N or h90 configuration of the mat region, whereas h-, the h90 configuration. Segregants h+ contained DNA duplication in the mat region. DNA rearrangements were not detected at the mating type locus, but the level of DNA DSB formation was drastically decreased in these segregants. Thus, our results show that genes rhp51+ and rhp55+ are involved not only in the repair of induced DNA DSB, but also in the mechanism of mating type switching in fission yeast.

Asunto(s)

Daño del ADN/genética , Reparación del ADN/genética , Proteínas de Unión al ADN/genética , Recombinasa Rad51/genética , Recombinación Genética/genética , Proteínas de Schizosaccharomyces pombe/genética , Schizosaccharomyces/genética , Daño del ADN/efectos de la radiación , Reparación del ADN/efectos de la radiación , Reordenamiento Génico/genética , Reordenamiento Génico/efectos de la radiación , Proteína Recombinante y Reparadora de ADN Rad52/genética , Radiación Ionizante , Recombinación Genética/efectos de la radiación

RESUMEN

Repair of DNA double-strand break (DSB) is an evolutionary conserved Rad51-mediated mechanism. In yeasts, Rad51 paralogs, Saccharomyces cerevisiae Rad55-Rad57 and Schizosaccharomyces pombe Rhp55-Rhp57 are mediators of the nucleoprotein RadS1 filament formation. As shown in this work, a novel RAD51Sp-dependent pathway of DSB repair acts in S. pombe parallel to the pathway mediated by Rad51 paralogs. A new gene dds20+ that controls this pathway was identified. The overexpression of dds20+ partially suppresses defects of mutant rhp55delta in DNA repair. Cells of dds20delta manifest hypersensitivity to a variety of genotoxins. Epistatic analysis revealed that dds20+ is a gene of the recombinational repair group. The role of Dds20 in repair of spontaneous damages occurring in the process of replication and mating-type switching remains unclear. The results obtained suggest that Dds20 has functions beyond the mitotic S phase. The Dds20 protein physically interacts with Rhp51 (Rad51Sp). Dds20 is assumed to operate at early recombinational stages and to play a specific role in the Rad51 protein filament assembly differing from that of Rad51 paralogs.

Asunto(s)

Reparación del ADN/genética , Proteínas de Unión al ADN/genética , Proteínas de Schizosaccharomyces pombe/genética , Schizosaccharomyces/genética , Regulación Fúngica de la Expresión Génica , Recombinasa Rad51

RESUMEN

Recombinational repair was first detected in budding yeast Saccharomyces cerevisiae and was also studied in fission yeast Schizosaccharomyces pombe over the recent decade. The discovery of Sch. pombe homologs of the S. cerevisiae RAD52 genes made it possible not only to identify and to clone their vertebrate counterparts, but also to study in detail the role of DNA recombination in certain cell processes. For instance, recombinational repair was shown to play a greater role in maintaining genome integrity in fission yeast and in vertebrates compared with S. cerevisiae. The present state of the problem of recombinational double-strand break repair in fission yeast is considered with a focus on comparisons between Sch. pombe and higher eukaryotes. The role of double-strand break repair in maintaining genome stability is discussed.

Asunto(s)

Reparación del ADN/genética , Genoma Fúngico , Recombinación Genética , Schizosaccharomyces/genética , Modelos Biológicos

RESUMEN

Schizosaccharomyces pombe Rhp55 and Rhp57 are RecA-like proteins involved in double-strand break (DSB) repair. Here we demonstrate that Rhp55 and Rhp57 proteins strongly interact in vivo, similar to Saccharomyces cerevisiae Rad55p and Rad57p. Mutations in the conserved ATP-binding/hydrolysis folds of both the Rhp55 and Rhp57 proteins impaired their function in DNA repair but not in cell proliferation. However, when combined, ATPase fold mutations in Rhp55p and Rhp57p resulted in severe defects of both functions, characteristic of the deletion mutants. Yeast two-hybrid analysis also revealed other multiple in vivo interactions among S. pombe proteins involved in recombinational DNA repair. Similar to S. cerevisiae Rad51p-Rad54p, S. pombe Rhp51p and Rhp54p were found to interact. Both putative Rad52 homologs in S. pombe, Rad22p and Rti1p, were found to interact with the C-terminal region of Rhp51 protein. Moreover, Rad22p and Rti1p exhibited mutual, as well as self-, interactions. In contrast to the S. cerevisiae interacting pair Rad51p-Rad55p, S. pombe Rhp51 protein strongly interacted with Rhp57 but not with Rhp55 protein. In addition, the Rti1 and Rad22 proteins were found to form a complex with the large subunit of S. pombe RPA. Our data provide compelling evidence that most, but not all, of the protein-protein interactions found in S. cerevisiae DSB repair are evolutionarily conserved.

Asunto(s)

Adenosina Trifosfatasas/genética , Reparación del ADN , Proteínas de Unión al ADN/genética , Recombinación Genética , Proteínas de Schizosaccharomyces pombe , Schizosaccharomyces/genética , Adenosina Trifosfatasas/metabolismo , Adenosina Trifosfato/metabolismo , Alelos , Animales , Cromosomas/metabolismo , ADN/metabolismo , ADN Helicasas/metabolismo , Proteínas de Unión al ADN/metabolismo , Dimerización , Evolución Molecular , Proteínas Fúngicas/metabolismo , Eliminación de Gen , Hidrólisis , Metilmetanosulfonato , Ratones , Modelos Biológicos , Mutágenos , Mutación , Plásmidos/metabolismo , Pruebas de Precipitina , Unión Proteica , Pliegue de Proteína , Estructura Terciaria de Proteína , Conejos , Recombinasa Rad51 , Técnicas del Sistema de Dos Híbridos

Asunto(s)

Bacillus subtilis/genética , ADN Bacteriano/genética , Origen de Réplica/genética , Secuencia de Bases , Cromosomas Bacterianos/genética , Datos de Secuencia Molecular , Plásmidos

RESUMEN

A new DNA repair gene from Schizosaccharomyces pombe with homology to RecA was identified and characterized. Comparative analysis showed highest similarity to Saccharomyces cerevisiae Rad55p. rhp55(+) (rad homologue pombe 55) encodes a predicted 350-amino-acid protein with an M(r) of 38,000. The rhp55Delta mutant was highly sensitive to methyl methanesulfonate (MMS), ionizing radiation (IR), and, to a lesser degree, UV. These phenotypes were enhanced at low temperatures, similar to deletions in the S. cerevisiae RAD55 and RAD57 genes. Many rhp55Delta cells were elongated with aberrant nuclei and an increased DNA content. The rhp55 mutant showed minor deficiencies in meiotic intra- and intergenic recombination. Sporulation efficiency and spore viability were significantly reduced. Double-mutant analysis showed that rhp55(+) acts in one DNA repair pathway with rhp51(+) and rhp54(+), homologs of the budding yeast RAD51 and RAD54 genes, respectively. However, rhp55(+) is in a different epistasis group for repair of UV-, MMS-, or gamma-ray-induced DNA damage than is rad22(+), a putative RAD52 homolog of fission yeast. The structural and functional similarity suggests that rhp55(+) is a homolog of the S. cerevisiae RAD55 gene and we propose that the functional diversification of RecA-like genes in budding yeast is evolutionarily conserved.

Asunto(s)

Reparación del ADN/genética , ADN de Hongos/genética , Proteínas de Unión al ADN , Escherichia coli/genética , Proteínas Fúngicas/genética , Genes Fúngicos , Rec A Recombinasas/genética , Recombinación Genética/genética , Proteínas de Saccharomyces cerevisiae , Proteínas de Schizosaccharomyces pombe , Schizosaccharomyces/genética , Secuencia de Aminoácidos , Daño del ADN , ADN Helicasas/genética , ADN de Hongos/metabolismo , Epistasis Genética , Proteínas Fúngicas/fisiología , Biblioteca de Genes , Genes Bacterianos , Prueba de Complementación Genética , Datos de Secuencia Molecular , Recombinasa Rad51 , Alineación de Secuencia , Eliminación de Secuencia , Homología de Secuencia de Aminoácido , Homología de Secuencia de Ácido Nucleico

RESUMEN

DNA sequencing of a region upstream of the mms223 gene of Bacillus subtilis showed the presence of two open reading frames, orf1 and orf2, which may encode 18- and 27-kDa polypeptides, respectively. The predicted amino acid sequence of the latter shows high similarity to a major autolysin of B. subtilis, CwlB, with 35% identity over 191 residues, as well as to other autolysins (CwlC, CwlM, and AmiB). The gene was tentatively named cwlD. Bright spores produced by a B. subtilis mutant with an insertionally inactivated cwlD gene were committed to germination by the addition of L-alanine, and spore darkening, a slow and partial decrease in A580, and 72% dipicolinic acid release compared with that of the wild-type strain were observed. However, degradation of the cortex was completely blocked. Spore germination of the cwlD mutant measured by colony formation after heat treatment was less than 3.7 x 10(-8). The germination deficiency of the cwlD mutant was only partially removed when the spores were treated with lysozyme. Analysis of the chromosomal transcription of cwlD demonstrated that a transcript (RNA2) appearing 3 h after initiation of sporulation may have originated from an internal sigma E-dependent promoter of the cwlD operon, and a longer transcript (RNA1) appearing 4.5 h after sporulation may have originated from a sigma G-dependent promoter upstream of the orf1 gene. The cwlD mutant harboring a B. subtilis vector plasmid containing the intact cwlD gene recovered germination at a frequency 26% of the wild-type level.

Asunto(s)

Bacillus subtilis/genética , Proteínas Bacterianas/genética , Regulación Bacteriana de la Expresión Génica/genética , N-Acetil Muramoil-L-Alanina Amidasa , Alanina/farmacología , Secuencia de Aminoácidos , Bacillus subtilis/efectos de los fármacos , Bacillus subtilis/enzimología , Bacillus subtilis/fisiología , Proteínas Bacterianas/biosíntesis , Proteínas Bacterianas/química , Secuencia de Bases , Pared Celular/enzimología , Genes Bacterianos/genética , Datos de Secuencia Molecular , Muramidasa/farmacología , Mutagénesis Insercional , Sistemas de Lectura Abierta , Ácidos Picolínicos/metabolismo , ARN Bacteriano/biosíntesis , ARN Mensajero/biosíntesis , Mapeo Restrictivo , Análisis de Secuencia de ADN , Homología de Secuencia de Aminoácido , Esporas Bacterianas/efectos de los fármacos , Esporas Bacterianas/genética , Transcripción Genética/genética

RESUMEN

To determine the minimal DNA sequence homology required for recombination in Bacillus subtilis, we developed a system capable of distinguishing between homologous and illegitimate recombination events during plasmid integration into the chromosome. In this system the recombination frequencies were measured between ts pE194 derivatives carrying segments of the chromosomal beta-gluconase gene (bglS) of various lengths and the bacterial chromosome, using selection for erythromycin resistance at the non-permissive temperature. Homologous recombination events, resulting in disruption of the bglS gene, were easily detected by a colorimetric assay for beta-gluconase activity. A linear dependence of recombination frequency on homology length was observed over an interval of 77 bp. It was found that approximately 70 bp of homology is required for detectable homologous recombination. Homologous recombination was not detected when only 25 bp of homology between plasmid and chromosome were provided. The data indicate that homology requirements for recombination in B. subtilis differ from those in Escherichia coli.

Asunto(s)

ADN Bacteriano/genética , Plásmidos , Recombinación Genética , Secuencia de Bases , Datos de Secuencia Molecular , Homología de Secuencia de Ácido Nucleico , Relación Estructura-Actividad