RESUMO
Cu pollution is a problem in mining areas in Peru. Here we evaluate the phytoextraction capacity, physiological and proteomic responses of four species growing in copper-contaminated areas in Arequipa, Peru. The plants used in the experiments were obtained by collecting seedlings (Tessaria integrifolia, Bacharis salicifolia), rhizomes (Eleocharis montevidensis) and seeds (Chenopodium murale) along a polluted river. They were exposed to solutions containing 2, 4, 8, 16 and 32 mg Cu L-1 during 20 days. Growth was affected in a concentration-dependent way. According to the tolerance index, B. salicifolia and C. murale were the most sensitive species, but with greater Cu phytoextraction capacity and accumulation in the biomass. The content and ratio of photosynthetic pigments changed differently for each specie and carotenoids level were less affected than chlorophyll. Cu also induced changes in the protein and sugar contents. Antioxidant enzyme activities (catalase and superoxide dismutase) increased with a decrease in the malondialdehyde. There were marked changes in the protein 2D-PAGE profiles with an increase in the abundance of metallothioneins (MT) of class II type I and II. Our results suggest that these species can grow in Cu polluted areas because they developed multiple tolerance mechanisms, such as and MTs production seems a important one.
Assuntos
Adaptação Biológica/efeitos dos fármacos , Cobre/toxicidade , Poluentes Ambientais/toxicidade , Metalotioneína/metabolismo , Desenvolvimento Vegetal/efeitos dos fármacos , Poluentes do Solo/toxicidade , Antioxidantes/metabolismo , Biodegradação Ambiental , Biomassa , Clorofila/metabolismo , Cobre/metabolismo , Poluentes Ambientais/metabolismo , Mineração , Peru , Raízes de Plantas/efeitos dos fármacos , Raízes de Plantas/crescimento & desenvolvimento , Raízes de Plantas/metabolismo , Proteômica , Plântula/efeitos dos fármacos , Plântula/crescimento & desenvolvimento , Plântula/metabolismo , Poluentes do Solo/metabolismo , Especificidade da EspécieRESUMO
Flavodoxins are small electron transfer proteins containing flavin mononucleotide (FMN) as a prosthetic group, which play an important role during oxidative stress or iron limitation. The aims of this study were the identification and characterization of flavodoxins in the model aromatic-degrader Paraburkholderia xenovorans LB400 and the analyses of their protective effects during oxidative stress induced by paraquat and H2O2. Two genes (BxeA0278 and BxeB0391) encoding flavodoxins (hereafter referred to as fldX for flavodoxin from P. xenovorans), were identified at the LB400 major and minor chromosome. Genomic context of the flavodoxin-encoding genes showed genes encoding membrane proteins, transporters, and proteins involved in redox processes and biosynthesis of macromolecules. A secondary structure prediction of both LB400 flavodoxins showed the characteristic flavodoxin structure of five ß-sheets intercalated with five α-helices. FldX1 contains a loop intercalated in the fifth ß-strand, which indicates that it belongs to the long-chain flavodoxins, whereas FldX2 is a short-chain flavodoxin. A phylogenetic analysis of 73 flavodoxins from 43 bacterial genera revealed eight clusters (I-VIII), while FldX1 and FldX2 grouped separately within a long-chain and a short-chain flavodoxin clades. FldX1 and FldX2 were overexpressed in P. xenovorans. Interestingly, the strain overexpressing the long-chain flavodoxin FldX1 (p2-fldX1) showed a faster growth in glucose than the control strain. The recombinant strain overexpressing the long-chain flavodoxin FldX1 (p2-fldx1) exposed to paraquat (20 mM) possessed lower susceptibility to growth inhibition on plates and higher survival in liquid medium than the control strain. The strains overexpressing the flavodoxins FldX1 and FldX2 showed higher survival during exposure to 1 mM paraquat (>95%) than the control strain (68%). Compared to the control strain, strains overexpressing FldX1 and FldX2 showed lower lipid peroxidation (>20%) after exposure to 1 mM paraquat and a lower protein carbonylation (~30%) after exposure to 1 mM H2O2 was observed. During exposure to paraquat, strain p2-fldx1 downregulated the katG4, hpf, trxB1 and ohr genes (> 2-fold), whereas strain p2-fldx2 upregulated the oxyR and ahpC1 genes (> 2-fold). In conclusion, the flavodoxins FldX1 and FldX2 of P. xenovorans LB400 conferred protection to cells exposed to the oxidizing agents paraquat and H2O2.
Assuntos
Adaptação Biológica/efeitos dos fármacos , Betaproteobacteria/efeitos dos fármacos , Betaproteobacteria/fisiologia , Flavodoxina/genética , Peróxido de Hidrogênio/farmacologia , Estresse Oxidativo/efeitos dos fármacos , Paraquat/farmacologia , Sequência de Aminoácidos , Biologia Computacional/métodos , Flavodoxina/química , Flavodoxina/metabolismo , Regulação Bacteriana da Expressão Gênica , Genoma Bacteriano , Genômica/métodos , FilogeniaRESUMO
Acinetobacter guillouiae SFC 500-1A, a native bacterial strain isolated from tannery sediments, is able to simultaneously remove high concentrations of Cr(VI) and phenol. In this complementary study, high-resolution microscopy techniques, such as atomic force microscopy (AFM) and transmission electron microscopy (TEM), were used to improve our understanding of some bacterial adaptive mechanisms that enhance their ability to survive. AFM contributed in gaining insight into changes in bacterial size and morphology. It allowed the unambiguous identification of pollutant-induced cellular disturbances and the visualization of bacterial cells with depth sensitivity. TEM analysis revealed that Cr(VI) produced changes mainly at the intracellular level, whereas phenol produced alterations at the membrane level. This strain tended to form more extensive biofilms after phenol treatment, which was consistent with microscopy images and the production of exopolysaccharides (EPSs). In addition, other exopolymeric substances (DNA, proteins) significantly increased under Cr(VI) and phenol treatment. These exopolymers are important for biofilm formation playing a key role in bacterial aggregate stability, being especially useful for bioremediation of environmental pollutants. This study yields the first direct evidences of a range of different changes in A. guillouiae SFC 500-1A which seems to be adaptive strategies to survive in stressful conditions.
Assuntos
Acinetobacter , Adaptação Biológica/efeitos dos fármacos , Cromo/toxicidade , Viabilidade Microbiana/efeitos dos fármacos , Fenol/toxicidade , Poluentes Químicos da Água/toxicidade , Acinetobacter/efeitos dos fármacos , Acinetobacter/ultraestrutura , Biodegradação Ambiental , Biofilmes/crescimento & desenvolvimento , Microscopia de Força Atômica , Microscopia Eletrônica de TransmissãoRESUMO
Abstract Pediococcus acidilactici strain K3 is an alcohol-tolerant lactic acid bacterium isolated from nuruk, which is a traditional Korean fermentation starter for makgeolli brewing. Draft genome of this strain was approximately 1,991,399 bp (G+C content, 42.1%) with 1525 protein-coding sequences (CDS), of which 44% were assigned to recognized functional genes. This draft genome sequence data of the strain K3 will provide insights into the genetic basis of its alcohol-tolerance.
Assuntos
Adaptação Biológica/efeitos dos fármacos , Adaptação Biológica/genética , Genoma Bacteriano , Etanol/farmacologia , Pediococcus acidilactici/efeitos dos fármacos , Pediococcus acidilactici/genética , Ácido Láctico/biossíntese , Biologia Computacional/métodos , Genômica/métodos , Etanol/metabolismo , Fermentação , Sequenciamento de Nucleotídeos em Larga Escala , Anotação de Sequência Molecular , Pediococcus acidilactici/isolamento & purificação , Pediococcus acidilactici/metabolismoRESUMO
Pediococcus acidilactici strain K3 is an alcohol-tolerant lactic acid bacterium isolated from nuruk, which is a traditional Korean fermentation starter for makgeolli brewing. Draft genome of this strain was approximately 1,991,399bp (G+C content, 42.1%) with 1525 protein-coding sequences (CDS), of which 44% were assigned to recognized functional genes. This draft genome sequence data of the strain K3 will provide insights into the genetic basis of its alcohol-tolerance.
Assuntos
Adaptação Biológica/efeitos dos fármacos , Adaptação Biológica/genética , Etanol/farmacologia , Genoma Bacteriano , Pediococcus acidilactici/efeitos dos fármacos , Pediococcus acidilactici/genética , Biologia Computacional/métodos , Etanol/metabolismo , Fermentação , Genômica/métodos , Sequenciamento de Nucleotídeos em Larga Escala , Ácido Láctico/biossíntese , Anotação de Sequência Molecular , Pediococcus acidilactici/isolamento & purificação , Pediococcus acidilactici/metabolismoRESUMO
Abstract Recently, there has been a lot of interest in the utilization of rhodococci in the bioremediation of petroleum contaminated environments. This study investigates the response of Rhodococcus erythropolis IBBPo1 cells to 1% organic solvents (alkanes, aromatics). A combination of microbiology, biochemical, and molecular approaches were used to examine cell adaptation mechanisms likely to be pursued by this strain after 1% organic solvent exposure. R. erythropolis IBBPo1 was found to utilize 1% alkanes (cyclohexane, n-hexane, n-decane) and aromatics (toluene, styrene, ethylbenzene) as the sole carbon source. Modifications in cell viability, cell morphology, membrane permeability, lipid profile, carotenoid pigments profile and 16S rRNA gene were revealed in R. erythropolis IBBPo1 cells grown 1 and 24 h on minimal medium in the presence of 1% alkanes (cyclohexane, n-hexane, n-decane) and aromatics (toluene, styrene, ethylbenzene). Due to its environmental origin and its metabolic potential, R. erythropolis IBBPo1 is an excellent candidate for the bioremediation of soils contaminated with crude oils and other toxic compounds. Moreover, the carotenoid pigments produced by this nonpathogenic Gram-positive bacterium have a variety of other potential applications.