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This study describes the first antibiofilm and antibacterial screening for plants from Caatinga against Ralstonia solanacearum, a causal agent of bacterial wilt that presents serious difficulties in control. There were prepared 22 aqueous extracts of plants collected in the Vale do Catimbau-PE, Brazil. The potential antibacterial activity was evaluated by absorbance in OD and the antibiofilm activity through the crystal violet method, both of them performed in microplate against isolates of R. solanacearum biofilm formers. The results of the screening showed that Jacaranda rugosa presented antimicrobial activity higher than 90%, while Harpochilus neesianus and Myroxylon peruiferum presented antibiofilm activity higher than 50% for all tested isolates. However, Croton heliotropiifolius showed both the activities, being thus very promising for application in the control of this phytopathogen. The search for viable alternatives to the development of new bioactive compounds safe for the environment, humans, and animals from an adverse and scarce environment such as the Caatinga and encouraged us to find plants that produce effective metabolites against phytopathogenic microorganisms. This in vitro screening is important to guide the development of new products in addition to guide research studies of bioactive compounds.

Cupriavidus necator was used for polyhydroxyalkanoate (PHA) production with the aim to compare the substrate consumption between pure glycerol (PG) and the glycerol obtained from biodiesel industry (GB). Shake flask experiments were performed with 20 g/L for both the carbon sources, incubated in a shaking incubator at 35 ºC for up to 72 h. At the end, the residual carbon source was analyzed by HPLC, the biomass recuperation for biopolymer extraction and biopolymer characterized by FTIR. The results demonstrated that 35.75 % of PG was consumed during biomass production, while 45.08 % was the value consumed for GB, which can indicate the higher PHA accumulation in GB-sample, as observed by microscopy analyses. Fourier Transform Infrared (FTIR) spectroscopy was performed to confirm the PHA nature of PG and GB samples, and confirmed the establishment of more hydrogen bonds in the PG one, suggesting the surplus of glycerol in the obtained-biopolymer. Since it is interesting the utilization of GB for obtaining added-value products along with biodiesel, this study reported the efficient production of PHA by C. necator using GB as carbon source and its promising use in the bioplastic industry as an alternative product for petrochemical plastics, foreseeing the improvement of a sustainable industry based on biofuels and biopolymers.

Spondias tuberosa Arruda (umbuzeiro), a Brazilian semiarid plant, is a species of great economic, social, and ecological importance. In folk medicine, the leaves have been used in the treatment of diabetes, inflammation, stomach and uterine pains, and constipation. In this study, the antioxidant properties of ethyl acetate and methanol leaves extracts were evaluated in vitro using different methods: free radicals elimination by DPPH and ABTS assays, and transition metal reduction by phosphomolybdenium assay. In addition, a phytochemical study was also carried out. The methanolic leaves extracts showed the strongest antioxidant activity and the higher values for total phenolic and flavonoids. The results showed that S. tuberosa leaves have antioxidant activity and this seems to be related to the phenolic content.

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ABSTRACT. Fusarium wilt caused by Fusarium oxysporum f. sp lycopersici (Fol) is one of the main diseases affecting tomatoes. The BHRS 2,3 genotype of tomato is, however, resistant to this disease. A proteomic approach was used to understand the defense mechanisms of this genotype using the tomato root, the first tissue that interacts with the fungus, as a target. Protein was extracted and separated by two-dimensional electrophoresis followed by staining with Coomassie brilliant blue. The proteins were identified by MALDI-TOF/TOF mass spectrometry. A total of 22 proteins were identified, 21 of which showed differential expression with 12 proteins being upregulated and nine being downregulated. Plants responded to the pathogen with increased expression of pathogenesis-related proteins. We noted the induction of proteins involved in hypersensitivity reaction and other defense mechanisms. The expression of proteins of primary metabolism related to energy production, however, decreased, as did the expression of two proteins related to defense against abiotic stress. These results demonstrate the presence of important mechanisms for defense against Fol in the tomato genotype BHRS 2,3.

BackgroundFinding the best extraction method of proteins from lysed cells is the key step for detection and identification in all proteomics applications. These are important to complement the knowledge about the mechanisms of interaction between plants and phytopathogens causing major economic losses. To develop an optimized extraction protocol, strains of Acidovorax citrulli, Pectobacterium carotovorum subsp. carotovorum and Ralstonia solanacearum were used as representative cells in the study of phytopathogenic bacteria. This study aims to compare four different protein extraction methods, including: Trizol, Phenol, Centrifugation and Lysis in order to determine which are more suitable for proteomic studies using as parameters the quantity and quality of extracted proteins observed in two-dimensional gels.ResultsThe bacteria studied showed different results among the tested methods. The Lysis method was more efficient for P. carotovorum subsp. carotovorum and R. solanacearum phytobacteria, as well as simple and fast, while for A. citrulli, the Centrifugation method was the best. This evaluation is based on results obtained in polyacrylamide gels that presented a greater abundance of spots and clearer and more consistent strips as detected by two-dimensional gels.ConclusionsThese results attest to the adequacy of these proteins extraction methods for proteomic studies.

Malafaia, C.B.; Barros, M.P.; Macedo, A.J.; Guerra, M. L.; Souza, E.B.; Correia, M.T.S.; Silva, M.V. 347