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A produção de biomassa e as absorções de N, P e K de quatro espécies forrageiras foram comparadas em três solos representativos da região semi-árida da Paraíba, cultivadas sem e com adubação orgânica. As espécies foram jureminha (Desmanthus virgatus), orelha-de-onça (Macroptilium martii), feijão-de-rolinha (Macroptilium lathyroides) e capim buffel (Cenchrus ciliaris); os solos foram Neossolo Flúvico, Neossolo Regolítico e Planossolo Háplico e a adubação foi realizada com esterco bovino (20 Mg ha-1) comparado com a testemunha. A adubação com esterco promoveu grandes incrementos na produção de biomassa e nas acumulações dos nutrientes, em todas as plantas e solos. O esterco parece ter suprido P às plantas em quantidades suficientes mas não de N e K, confirmando que é uma boa fonte do primeiro elemento. O feijão de rolinha e a orelha de onça tiveram as maiores capacidades de acumulação de biomassa, principalmente em resposta à adubação. O capim buffel atinge maiores teores e conteúdos de K na matéria seca que as leguminosas. Não houve correspondência entre a análise dos solos e sua capacidade de suprimento de nutrientes.Biomass production and N, P and K uptake by four forage species were compared in three soils from the semi-arid region of Paraíba, with or without organic manure. The species were three legumes (Desmanthus virgatus , Macroptilium martii and Macroptilium lathyroides) and one grass (Cenchrus ciliaris); the soils, a Fluvic Neosol, a Regolithic Neosol and Haplic Planosol; and cattle manure was applied at a dose equivalent to 20 Mg ha-1. Manure application resulted in large increases in biomass production and nutrient uptake, in all species and soils. Apparently, the manure supplied enough P but not enough N and K to the plants, confirming that it is a good source of the first nutrient. Macroptilium martii and Macroptilium lathyroides seem to be the highest biomass producers, mainly in response to fertilization. Cenchrus ciliaris had higher K concentrations and contents than the legumes, indicating a larger K absorption capacity. There was no correspondence between soil analysis and nutrient supplying capacity.

Background: Leptospirosis is a zoonotic infectious disease that affects both humans and animals. The existing genetic tools for Leptospira spp. have improved our understanding of the biology of this spirochete as well as the interaction of pathogenic leptospires with the mammalian host. However, new tools are necessary to provide novel and useful information to the field. Methodology and Principal Findings: A series of promoter-probe vectors carrying a reporter gene encoding green fluorescent protein (GFP) were constructed for use in L. biflexa. They were tested by constructing transcriptional fusions between the lipL41, Leptospiral Immunoglobulin-like A (ligA) and Sphingomyelinase 2 (sph2) promoters from L. interrogans and the reporter gene. ligA and sph2 promoters were the most active, in comparison to the lipL41 promoter and the non-induced controls. The results obtained are in agreement with LigA expression from the L. interrogans Fiocruz L1-130 strain. Conclusions: The novel vectors facilitated the in vitro evaluation of L. interrogans promoter activity under defined growth conditions which simulate the mammalian host environment. The fluorescence and rt-PCR data obtained closely reflected transcriptional regulation of the promoters, thus demonstrating the suitability of these vectors for assessing promoter activity in L. biflexa.