RESUMEN
AIMS: To evaluate the antibiofilm potential of water-soluble Moringa oleifera seed lectin (WSMoL) on Serratia marcescens and Bacillus sp. METHODS AND RESULTS: WSMoL inhibited biofilm formation by S. marcescens at concentrations lower than 2·6 µg ml-1 and impaired bacterial growth at higher concentrations, avoiding biofilm formation. For Bacillus sp., the lectin inhibited bacterial growth at all concentrations. The antibiofilm action of WSMoL is associated with damage to bacterial cells. WSMoL did not disrupt preformed S. marcescens biofilms but was able to damage cells inside them. On the other hand, the lectin reduced the number of cells in Bacillus sp. biofilm treated with it. WSMoL was able to control biofilm formation when immobilized on glass surface (116 µg cm-2 ), damaging S. marcescens cells and avoiding adherence of Bacillus sp. cells on glass. The Bacillus sp. isolate is member of Bacillus subtilis species complex and closely related to species of the conspecific 'amyloliquefaciens' group. CONCLUSION: WSMoL prevented biofilm development by S. marcescens and Bacillus sp. and the antibiofilm effect is also observed when the lectin is immobilized on glass. SIGNIFICANCE AND IMPACT OF THE STUDY: Taking together, our results provide support to the potential use of WSMoL for controlling biofilm formation by bacteria.
Asunto(s)
Antibacterianos/farmacología , Bacillus/efectos de los fármacos , Biopelículas/efectos de los fármacos , Lectinas/farmacología , Moringa oleifera/química , Extractos Vegetales/farmacología , Serratia marcescens/efectos de los fármacos , Antibacterianos/aislamiento & purificación , Bacillus/fisiología , Lectinas/aislamiento & purificación , Extractos Vegetales/aislamiento & purificación , Semillas/química , Serratia marcescens/fisiologíaRESUMEN
Gene expression related to drought response in the leaf tissues of two Brazilian upland cultivars, the drought-tolerant Douradão and the drought-sensitive Primavera, was analyzed. RNA-seq identified 27,618 transcripts in the Douradão cultivar, with 24,090 (87.2%) homologous to the rice database, and 27,221 transcripts in the Primavera cultivar, with 23,663 (86.9%) homologous to the rice database. Gene-expression analysis between control and water-deficient treatments revealed 493 and 1154 differentially expressed genes in Douradão and Primavera cultivars, respectively. Genes exclusively expressed under drought were identified for Douradão, including two genes of particular interest coding for the protein peroxidase precursor, which is involved in three distinct metabolic pathways. Comparisons between the two drought-exposed cultivars revealed 2314 genes were differentially expressed (978 upregulated, 1336 downregulated in Douradão). Six genes distributed across 4 different transcription factor families (bHLH, MYB, NAC, and WRKY) were identified, all of which were upregulated in Douradão compared to Primavera during drought. Most of the genes identified in Douradão activate metabolic pathways responsible for production of secondary metabolites and genes coding for enzymatically active signaling receptors. Quantitative PCR validation showed that most gene expression was in agreement with computational prediction of these transcripts. The transcripts identified here will define molecular markers for identification of Cis-acting elements to search for allelic variants of these genes through analysis of polymorphic SNPs in GenBank accessions of upland rice, aiming to develop cultivars with the best combination of these alleles, resulting in materials with high yield potential in the event of drought during the reproductive phase.
Asunto(s)
Adaptación Fisiológica/genética , Sequías , Ecotipo , Regulación de la Expresión Génica de las Plantas , Genes de Plantas , Oryza/genética , Oryza/fisiología , Clima Tropical , Secuencia de Bases , Regulación hacia Abajo/genética , Perfilación de la Expresión Génica , Ontología de Genes , Redes y Vías Metabólicas/genética , Anotación de Secuencia Molecular , Hojas de la Planta/genética , Reacción en Cadena en Tiempo Real de la Polimerasa , Reproducibilidad de los Resultados , Análisis de Secuencia de ARN , Estrés Fisiológico/genética , Factores de Transcripción/metabolismo , Regulación hacia Arriba/genéticaRESUMEN
AIMS: To develop a polymerase chain reaction (PCR)-based approach for the detection of nifH gene-containing Paenibacillus in environmental samples. METHODS AND RESULTS: The primers, nifHPAENf and nifHPAENr, were designed and tested with DNA from: (i) strains of different nitrogen-fixing Paenibacillus species, (ii) strains of other nitrogen-fixing genera and (iii) rhizosphere of sorghum sown in Cerrado soil amended with either 12 or 120 kg ha(-1) of nitrogen fertilizer. All nitrogen-fixing Paenibacillus strains tested and the DNA samples from rhizosphere soil were amplified when these primers were used, generating a 280 bp fragment. When the PCR products obtained from both sorghum rhizospheres were cloned and sequenced, the majority of the clones analysed could be identified as Paenibacillus durus. Moreover, a greater diversity in the nifH sequences could be observed in the rhizosphere treated with a high amount of nitrogen fertilizer. CONCLUSIONS: Nitrogen fertilization slightly influenced the structure of the nifH gene-containing Paenibacillus community in sorghum rhizospheres cultivated in Cerrado soil. SIGNIFICANCE AND IMPACT OF THE STUDY: The PCR detection method developed is adequate to assess the presence of nifH gene-containing Paenibacillus in the environment and can be used in future to determine the ecological role of this group of micro-organisms for the nitrogen input to the plants.
Asunto(s)
Bacterias/genética , Bacterias/aislamiento & purificación , Proteínas Bacterianas/genética , Oxidorreductasas/genética , Raíces de Plantas/microbiología , Microbiología del Suelo , Sorghum/microbiología , Bacterias/enzimología , Biodiversidad , Datos de Secuencia MolecularRESUMEN
The texture of corn grains is a fundamental characteristic for the industry as well as for grain producers and processors. To further understand the mechanisms involved in grain hardness, contrasting corn cultivars for grain hardness and protein quality were evaluated. The cultivars were Cateto L237/67 (hard endosperm and low protein value), QPM BR 451 (semi-hard endosperm and high protein value); Bolivia-2 (floury endosperm and low protein value), and Opaque-2 (floury endosperm and high protein value). Evaluations were carried out at 10, 20, 30, 40, 50, and 60 days after pollination in developing corn grains and in the mature grain. In developing grains, evaluation consisted in the determination of the area, percentage of starch granules, distribution of starch granules, and protein bodies in the endosperm. In mature corn grains, the parameters evaluated were: density, percentage of total proteins, levels of lysine and tryptophan, and banding pattern of zeins. The results indicate that the higher physical resistance of corn grains from the cultivars analyzed is influenced by the high percentage of total proteins, high synthesis of 27-kDa zeins, presence of protein bodies, and perfect organization of starch granules in the endosperm, independent of their sizes.
Asunto(s)
Grano Comestible/metabolismo , Zea mays/metabolismo , Proteínas de Unión al ADN/metabolismo , Grano Comestible/crecimiento & desarrollo , Grano Comestible/normas , Peso Molecular , Proteínas de Plantas/metabolismo , Semillas/metabolismo , Almidón/metabolismo , Factores de Transcripción/metabolismo , Zea mays/crecimiento & desarrollo , Zea mays/normas , Zeína/química , Zeína/metabolismoRESUMEN
The texture of corn grains is a fundamental characteristic for the industry as well as for grain producers and processors. To further understand the mechanisms involved in grain hardness, contrasting corn cultivars for grain hardness and protein quality were evaluated. The cultivars were Cateto L237/67 (hard endosperm and low protein value), QPM BR 451 (semi-hard endosperm and high protein value); Bolivia-2 (floury endosperm and low protein value), and Opaque-2 (floury endosperm and high protein value). Evaluations were carried out at 10, 20, 30, 40, 50, and 60 days after pollination in developing corn grains and in the mature grain. In developing grains, evaluation consisted in the determination of the area, percentage of starch granules, distribution of starch granules, and protein bodies in the endosperm. In mature corn grains, the parameters evaluated were: density, percentage of total proteins, levels of lysine and tryptophan, and banding pattern of zeins. The results indicate that the higher physical resistance of corn grains from the cultivars analyzed is influenced by the high percentage of total proteins, high synthesis of 27-kDa zeins, presence of protein bodies, and perfect organization of starch granules in the endosperm, independent of their sizes.