Non-synonymous polymorphisms in candidate gene associated with growth traits in Channel catfish (Ictalurus punctatus, Rafinesque, 1818).

Resequencing of Myostatin, Growth Hormone, Follistatin-A-like, Insulin-like Growth Factor I (IGF-I) and Myogenin (MYOG) genes was completed to discover novel genetic variations and assess non synonymous (ns) polymorphisms (SNPs) effect on growth related traits of channel catfish. Wild and farmed animals were used as a discovering population. Resequencing lead to the identification of 59 new variants in the five analyzed genes; 66% found in introns and 34% in coding regions. From coding regions, 14 variants were synonyms and six were ns variations. A mutation rate of one in 129 bp was estimated. Four ns variations were selected for validation and association analysis. In IGF-I two ns polymorphisms, at IGF-I19 the G wild type allele was fixed in population and for IGF-I63 the C allele had a frequency of 0.972 and for mutate allele G of 0.027. In MYOG two ns SNPs were assessed. MYOG131 presented a frequency of alleles T and A, of 0.754 and 0.246, respectively and MYOG233, with a frequency of G and C of 0.775 and 0.225, respectively. Only MYOG131 (g.529T>A) was significantly associated (P < 0.04) to some growth traits. Results suggest MYOG131 g.529T>A as candidate locus for genetic enhancement of growth traits in channel catfish.

The detection of inherent homologous recombination between repeat sequences in H. pylori 26695 by the PCR-based method.

Helicobacter pylori infects more than half of the world's population, making it the most widespread infection of bacteria. It has high genetic diversity and has been considered as one of the most variable bacterial species. In the present study, a PCR-based method was used to detect the presence and the relative frequency of homologous recombination between repeat sequences (>500 bp) in H. pylori 26695. All the recombinant structures have been confirmed by sequencing. The inversion generated between inverted repeats showed distinct features from the recombination for duplication or deletion between direct repeats. Meanwhile, we gave the mathematic reasoning of a general formula for the calculation of relative recombination frequency and indicated the conditions for its application. This formula could be extensively applied to detect the frequency of homologous recombination, site-specific recombination, and other types of predictable recombination. Our results should be helpful for better understanding the genome evolution and adaptation of bacteria.

Efecto de diferentes concentraciones de ácido antranílico en el crecimiento del maíz / The effect of different anthranilic acid concentrations on maize growth

La rizobacteria Azospirillum brasilense basa su capacidad promotora del crecimiento vegetal en la producciónde auxinas y otras hormonas, entre ellas el ácido antranílico (AA). En este trabajo se determinó el efectodel AA (0, 500, 1000, 3000 y 5000 ppm) en el crecimiento y la acumulación de biomasa del híbrido de maíz83G66 en condiciones de invernadero. El AA de 500 a 3000 ppm promovió un mayor crecimiento (área foliary altura de planta), y el AA de 1000 y 3000 ppm incrementó significativamente la biomasa seca en maíz encomparación con el testigo. El 90% de la asimilación del AA en las plantas ocurrió durante los primeros 10días después del tratamiento.

The plant growth-promoting ability of rhizo-bacterium Azospirillum brasilense is based on production of auxins and other hormones, among them outstanding antranilic acid (AA). In this work we determined the antranilic acid (0, 500, 1000, 3000, and 5000 ppm) effects on maize growth and dry biomass accumulation under greenhouse conditions using the hybrid 83G66. From 500 to 3000 ppm of AA significantly increased plant growth (leaf area and plant height) while 1000 and 3000 ppm of AA significantly increased dry biomass accumulation in maize compared with control (0 ppm). The 90 % of AA in maize plants was assimilated during the early 10 days after treatment.