Copper accumulation in Xanthomonas campestris pv. vesicatoria

Ramos, Georgia Barros de A.; Rosato, Yoko Bomura

doi:10.1590/s0100-84551996000400002

Cited by 1 publication

(1 citation statement)

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“…vesicatoria copper resistant strain. 7 The role of EPS in the Xac Cu 2+ resistance mechanism was analyzed by FTIR, EPR and NMR spectroscopies. Figure 2 shows the FTIR spectra of the Xac cells (2a) with its exopolisacharide and the exopolysaccharide, xanthan gum (2b), which is released into the medium as slime.…”

Section: Resultsmentioning

confidence: 99%

Spectroscopic characterization of the exopolysaccharide of Xanthomonas axonopodis pv. citri in Cu2+ resistance mechanism

Osiro¹,

Franco²,

Colnago³

2011

J. Braz. Chem. Soc.

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Analizou-se o papel do exopolissacarídeo (EPS) no mecanismo de resistência ao Cu 2+ da Xanthomonas axonopodis pv. citri (Xac) com as espectroscopias de infravermelho com transformada de Fourier (FTIR), ressonância paramagnética eletrônica (RPE) e ressonância magnética nuclear (RMN). Os dados de FTIR demonstraram que as células cultivadas na presença de 0.2 mmol L -1 de CuSO 4 produziram uma maior quantidade de exopolissacarídeo piruvatado do que as células cultivadas na sua ausência. Os dados de RPE indicaram que a quantidade de íons Cu 2+ diminuiu com o tempo de cultura. Os dados de RMN de 13 C mostraram a complexação dos íons de Cu 2+ com o EPS. Esses resultados mostraram que o EPS tem um papel importante no mecanismo de proteção da Xac ao Cu 2+ e este age no mecanismo inicial de proteção, ligando-se aos íons de Cu 2+ livres, reduzindo sua difusão e o transporte ativo ao citoplasma . O Cu 2+ também induz a produção de EPS piruvatado, que aumenta a capacidade de coleta e complexação desses íons.We analyzed the role of exopolysaccharide in the Xanthomonas axonopodis pv. citri (Xac) Cu 2+ resistance mechanism by Fourier transform infrared (FTIR), electron paramagnetic resonance (EPR) and nuclear magnetic resonance (NMR) spectroscopies. The FTIR data show that cells cultivated in the presence of 0.2 mmol L -1 of CuSO 4 produce larger amounts of pyruvated exopolissacharide (EPS) than the ones cultivated in its absence. The EPR data indicate that the amount of Cu 2+ decreases with cultivation time. The 13 C-CPMAS NMR data also show the complexation of Cu 2+ ions to the EPS. The results demonstrate that EPS plays an important role in Xac Cu 2+ protection. Both capsular and slime EPS act as an initial protection mechanism, binding free Cu 2+ ions, reducing their diffusion and their active transport to the cytoplasm. Cu 2+ also induces the production of a highly pyruvated negative EPS, increasing its capture and binding capacity.

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Section: Resultsmentioning

confidence: 99%