RESUMO
OBJECTIVES: To determine furfural biotransformation capabilities of Acinetobacter baylyi ADP1 and Acinetobacter schindleri ACE. RESULTS: Acinetobacter baylyi ADP1 and A. schindleri ACE could not use furfural as sole carbon source but when acetate was used as substrate, ADP1 and ACE biotransformed 1 g furfural/l in 5 and 9 h, respectively. In both cases, the product of this biotransformation was difurfuryl-ether as shown by FT-IR and 1H and 13C NMR spectroscopy. The presence of furfural decreased the specific growth rate in acetate by 27% in ADP1 and 53% in ACE. For both strains, the MIC of furfural was 1.25 g/l. Nonetheless, ADP1 biotransformed 2 g furfural/l at a rate of 1 g/l/h in the stationary phase of growth. A transcriptional analysis of possible dehydrogenases involved in this biotransformation, identified that the areB and frmA genes were highly overexpressed after the exposure of ADP1 to furfural. The products of these genes are a benzyl-alcohol dehydrogenase and an alcohol dehydrogenase. CONCLUSIONS: Acinetobacter baylyi ADP1 is a candidate for the biological detoxification of furfural, a fermentation inhibitor present in lignocellulosic hydrolysates, with the possible direct involvement of the AreB and FrmA enzymes in the process.
Assuntos
Acinetobacter/metabolismo , Furaldeído/metabolismo , Acetatos/metabolismo , Acinetobacter/efeitos dos fármacos , Acinetobacter/genética , Acinetobacter/crescimento & desenvolvimento , Oxirredutases do Álcool/genética , Oxirredutases do Álcool/metabolismo , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Biotransformação , Furaldeído/farmacologia , Furanos/metabolismo , Furanos/farmacologia , Regulação Bacteriana da Expressão Gênica/efeitos dos fármacosRESUMO
Acinetobacter baylyi ADP1 is a microorganism with the potential to produce storage lipids. Here, a systematic study was carried out to evaluate growth performance and accumulation of wax esters and triacylglycerols using glycerol, xylose, glucose, acetate, ethanol, and pyruvate as carbon sources. High specific growth rates (µ) were found in gluconeogenic carbon sources (ethanol, acetate, and pyruvate: 0.94 ± 0.18, 0.93 ± 0.06, and 0.61 ± 0.01 h-1, respectively), and low in glucose (0.25 ± 0.01 h-1). Interestingly, these µ values were sustained in a broad range of concentrations of glucose (0.5-50 g L-1), pyruvate (3-10 g L-1), and acetate (0.3-2 g L-1), suggesting a high tolerance to glucose and pyruvate. It was observed that ADP1 is not able to use glycerol or xylose as unique carbon sources. On the other hand, ADP1 showed sensitivity to osmotic upshifts, noted by the lysis at the beginning of cultivations on different carbon sources. However, ADP1 is adapted to relatively high substrate concentrations as indicated by the minimal inhibitory concentrations (MICs) determined at 24 h of cultivations: 350, 50, 80, and 15 g L-1 for glucose, ethanol, pyruvate, and acetate, respectively. Remarkably, ADP1 co-utilized glucose, acetate, ethanol, and pyruvate. Finally, the accumulation of storage lipids, wax esters (WEs), and triacylglycerols (TAGs) showed to be substrate dependent. Under nitrogen-limiting conditions, the TAGs:WEs (mol:mol) accumulation ratios were 1:4.9 in pyruvate and 1:1.6 in glucose, the WEs were mainly accumulated in acetate. In ethanol, no accumulation of lipids was detected.
Assuntos
Acinetobacter/crescimento & desenvolvimento , Acinetobacter/metabolismo , Carbono/metabolismo , Meios de Cultura/química , Metabolismo dos Lipídeos , Lipídeos/análise , Acinetobacter/químicaRESUMO
High levels of arsenic present in the High Altitude Andean Lakes (HAALs) ecosystems selected arsenic-resistant microbial communities which are of novel interest to study adaptations mechanisms potentially useful in bioremediation processes. We herein performed a detailed characterization of the arsenic tolerance profiles and the biofilm production of two HAAL polyextremophiles, Acinetobacter sp. Ver3 (Ver3) and Exiguobacterium sp. S17 (S17). Cellular adherence over glass and polypropylene surfaces were evaluated together with the effect of increasing doses and oxidative states of arsenic over the quality and quantity of their biofilm production. The arsenic tolerance outcomes showed that HAAL strains could tolerate higher arsenic concentrations than phylogenetic related strains belonging to the German collection of microorganisms and cell cultures (Deutsche Sammlung von Mikroorganismen und Zellkulturen, DSMZ), which suggest adaptations of HAAL strains to their original environment. On the other hand, the crystal violet method (CV) and SEM analysis showed that Ver3 and S17 were able to attach to solid surfaces and to form the biofilm. The quantification of biofilms production in 48 hours' cultures through CV shows that Ver3 yielded higher production in the treatment without arsenic cultured on a glass support, while S17 yield higher biofilm production under intermediate arsenic concentration on glass supports. Polypropylene supports had negative effects on the biofilm production of Ver3 and S17. SEM analysis shows that the highest biofilm yields could be associated with a larger number of attached cells as well as the development of more complex 3D multicellular structures.
Assuntos
Acinetobacter/crescimento & desenvolvimento , Adaptação Fisiológica/genética , Ecossistema , Filogenia , Acinetobacter/efeitos dos fármacos , Acinetobacter/genética , Altitude , Arsênio/toxicidade , Biodegradação Ambiental , Biofilmes/efeitos dos fármacos , Biofilmes/crescimento & desenvolvimento , Lagos/microbiologia , Raios UltravioletaRESUMO
Metal contamination exerts environmental pressure on several lifeforms. Since metals are non-biodegradable and recalcitrant, they accumulate in living beings and spread through the food chain. Thus, many life forms are affected by environmental metal contamination, such as plants and microorganisms. In the case of microorganisms, scarce information is available on how metals affect them. As a highly resistant form of life, microorganisms can adapt to several environmental pressures through genetic modifications, changing their metabolism to overcome new conditions, and continuing to thrive in the same place. In this study, an Acinetobacter sp. strain was isolated from a copper mine, which presented very high resistance to copper, growing in copper concentrations of up to 7 mM. As a result of its metabolic response in the presence of 3 mM of copper, the expression of 35 proteins in total was altered. The proteins were identified to be associated with the glycolytic pathway, membrane transport, biosynthesis and two proteins directly involved in copper homeostasis (CopA and CopB).
Assuntos
Acinetobacter/metabolismo , Cobre/toxicidade , Proteômica , Acinetobacter/efeitos dos fármacos , Acinetobacter/crescimento & desenvolvimento , Acinetobacter/isolamento & purificação , Proteínas de Bactérias/metabolismo , Eletroforese em Gel Bidimensional , Amplificação de Genes , Genes Bacterianos , Testes de Sensibilidade Microbiana , Transdução de Sinais/efeitos dos fármacosRESUMO
This study explores the potential of lead resistant bacterium Acinetobacter junii Pb1 for adsorption/accumulation of lead using various techniques. In the present work, growth of A. junii Pb1 was investigated in the presence of a range of Pb(II) concentrations (0, 100, 250, 500, and 1000 mg l-1). Lead was found to have no toxic effect on the growth of A. junii Pb1 at 100 and 250 mg l-1 concentrations. However, further increase in Pb(II) concentration (500 mg l-1) showed increase in lag phase, though growth remained unaffected and significant growth inhibition was observed when concentration was increased to 1000 mg l-1. Same was confirmed by the observations of flow cytometry. Further, the effect of Pb(II) on A. junii Pb1 was evaluated by using fluorescence microscopy, spectrofluorimetry, and flow cytometry. The spectrofluorimetry and fluorescence microscopy results revealed the accumulation of Pb(II) inside the bacterial cells as evident by green fluorescence due to lead binding fluorescent probe, Leadmium Green AM dye. Flow cytometry observations indicate an increase in cell size and granularity of exposure to lead. Thus, present work provides a new understanding of Pb(II) tolerance in A. junii Pb1 and its potential use in remediation of lead from contaminated soil.
Assuntos
Acinetobacter/metabolismo , Chumbo/metabolismo , Acinetobacter/efeitos dos fármacos , Acinetobacter/crescimento & desenvolvimento , Biodegradação Ambiental , Citometria de Fluxo , Chumbo/análise , Chumbo/toxicidadeRESUMO
Acinetobacter species are identified as producing surface-active and emulsifying molecules known as bioemulsifiers. Production, characterization and stability of bioemulsifiers produced by Acinetobacter bouvetii UAM25 were studied. A. bouvetii UAM25 grew in three different carbon and energy sources: ethanol, a glycerol-hexadecane mixture and waste cooking oil in an airlift bioreactor, showing that bioemulsifier production was growth associated. The three purified bioemulsifiers were lipo-heteropolysaccharides of high molecular weight (4866 ± 533 and 462 ± 101 kDa). The best carbon source and energy for bioemulsifier production was wasted cooking oil, with a highest emulsifying capacity (76.2 ± 3.5 EU mg-1) as compared with ethanol (46.6 ± 7.1 EU mg-1) and the glycerol-hexadecane mixture (49.5 ± 4.2 EU mg-1). The three bioemulsifiers in our study displayed similar macromolecular structures, regardless of the nature (hydrophobic or hydrophilic) of the carbon and energy source. Bioemulsifiers did not decrease surface tension, but the emulsifying capacity of all of them was retained under extreme variation in salinity (0-50 g NaCl L-1), pH (3-10) and temperature (25-121 °C), indicative of remarkable stability. These findings contribute to understanding of the relationship between: production, physical properties, chemical composition and stability of bioemulsifiers for their potential applications in biotechnology, such as bioremediation of hydrocarbon-contaminated soil and water.
Assuntos
Acinetobacter/crescimento & desenvolvimento , Alcanos/farmacologia , Meios de Cultura/farmacologia , Emulsificantes/metabolismo , Etanol/farmacologia , Glicerol/farmacologia , Alcanos/química , Meios de Cultura/química , Etanol/química , Glicerol/químicaRESUMO
The pH of the culture medium directly influences the growth of microorganisms and the chemical processes that they perform. The aim of this study was to assess the influence of the initial pH of the culture medium on the production of 11 low-molecular-weight organic acids and on the solubilization of calcium phosphate by bacteria in growth medium (NBRIP). The following strains isolated from cowpea nodules were studied: UFLA03-08 (Rhizobium tropici), UFLA03-09 (Acinetobacter sp.), UFLA03-10 (Paenibacillus kribbensis), UFLA03-106 (Paenibacillus kribbensis) and UFLA03-116 (Paenibacillus sp.). The strains UFLA03-08, UFLA03-09, UFLA03-10 and UFLA03-106 solubilized Ca3(PO4)2 in liquid medium regardless of the initial pH, although without a significant difference between the treatments. The production of organic acids by these strains was assessed for all of the initial pH values investigated, and differences between the treatments were observed. Strains UFLA03-09 and UFLA03-10 produced the same acids at different initial pH values in the culture medium. There was no correlation between phosphorus solubilized from Ca3(PO4)2 in NBRIP liquid medium and the concentration of total organic acids at the different initial pH values. Therefore, the initial pH of the culture medium influences the production of organic acids by the strains UFLA03-08, UFLA03-09, UFLA03-10 and UFLA03-106 but it does not affect calcium phosphate solubilization.
Assuntos
Acinetobacter/metabolismo , Ácidos Carboxílicos/metabolismo , Meios de Cultura/química , Paenibacillus/metabolismo , Fosfatos/metabolismo , Rhizobium tropici/metabolismo , Acinetobacter/crescimento & desenvolvimento , Acinetobacter/isolamento & purificação , Fabaceae/microbiologia , Concentração de Íons de Hidrogênio , Paenibacillus/crescimento & desenvolvimento , Paenibacillus/isolamento & purificação , Rhizobium tropici/crescimento & desenvolvimento , Rhizobium tropici/isolamento & purificação , Nódulos Radiculares de Plantas/microbiologiaRESUMO
The pH of the culture medium directly influences the growth of microorganisms and the chemical processes that they perform. The aim of this study was to assess the influence of the initial pH of the culture medium on the production of 11 low-molecular-weight organic acids and on the solubilization of calcium phosphate by bacteria in growth medium (NBRIP). The following strains isolated from cowpea nodules were studied: UFLA03-08 (Rhizobium tropici), UFLA03-09 (Acinetobacter sp.), UFLA03-10 (Paenibacillus kribbensis), UFLA03-106 (Paenibacillus kribbensis) and UFLA03-116 (Paenibacillus sp.). The strains UFLA03-08, UFLA03-09, UFLA03-10 and UFLA03-106 solubilized Ca3(PO4)2 in liquid medium regardless of the initial pH, although without a significant difference between the treatments. The production of organic acids by these strains was assessed for all of the initial pH values investigated, and differences between the treatments were observed. Strains UFLA03-09 and UFLA03-10 produced the same acids at different initial pH values in the culture medium. There was no correlation between phosphorus solubilized from Ca3(PO4)2 in NBRIP liquid medium and the concentration of total organic acids at the different initial pH values. Therefore, the initial pH of the culture medium influences the production of organic acids by the strains UFLA03-08, UFLA03-09, UFLA03-10 and UFLA03-106 but it does not affect calcium phosphate solubilization.(AU)
Assuntos
Acinetobacter/metabolismo , Ácidos Carboxílicos/metabolismo , Meios de Cultura/química , Paenibacillus/metabolismo , Fosfatos/metabolismo , Rhizobium tropici/metabolismo , Acinetobacter/crescimento & desenvolvimento , Acinetobacter/isolamento & purificação , Fabaceae/microbiologia , Concentração de Íons de Hidrogênio , Paenibacillus/crescimento & desenvolvimento , Paenibacillus/isolamento & purificação , Rhizobium tropici/crescimento & desenvolvimento , Rhizobium tropici/isolamento & purificação , Nódulos Radiculares de Plantas/microbiologiaRESUMO
The pH of the culture medium directly influences the growth of microorganisms and the chemical processes that they perform. The aim of this study was to assess the influence of the initial pH of the culture medium on the production of 11 low-molecular-weight organic acids and on the solubilization of calcium phosphate by bacteria in growth medium (NBRIP). The following strains isolated from cowpea nodules were studied: UFLA03-08 (Rhizobium tropici), UFLA03-09 (Acinetobacter sp.), UFLA03-10 (Paenibacillus kribbensis), UFLA03-106 (Paenibacillus kribbensis) and UFLA03-116 (Paenibacillus sp.). The strains UFLA03-08, UFLA03-09, UFLA03-10 and UFLA03-106 solubilized Ca3(PO4)2 in liquid medium regardless of the initial pH, although without a significant difference between the treatments. The production of organic acids by these strains was assessed for all of the initial pH values investigated, and differences between the treatments were observed. Strains UFLA03-09 and UFLA03-10 produced the same acids at different initial pH values in the culture medium. There was no correlation between phosphorus solubilized from Ca3(PO4)2 in NBRIP liquid medium and the concentration of total organic acids at the different initial pH values. Therefore, the initial pH of the culture medium influences the production of organic acids by the strains UFLA03-08, UFLA03-09, UFLA03-10 and UFLA03-106 but it does not affect calcium phosphate solubilization.
Assuntos
Acinetobacter/metabolismo , Ácidos Carboxílicos/metabolismo , Meios de Cultura/química , Paenibacillus/metabolismo , Fosfatos/metabolismo , Rhizobium tropici/metabolismo , Acinetobacter/crescimento & desenvolvimento , Acinetobacter/isolamento & purificação , Fabaceae/microbiologia , Concentração de Íons de Hidrogênio , Paenibacillus/crescimento & desenvolvimento , Paenibacillus/isolamento & purificação , Rhizobium tropici/crescimento & desenvolvimento , Rhizobium tropici/isolamento & purificação , Nódulos Radiculares de Plantas/microbiologiaRESUMO
This study evaluated the potential of bacterial isolates from mangrove sediments to degrade hexadecane, an paraffin hydrocarbon that is a large constituent of diesel and automobile lubricants. From a total of 18 oil-degrading isolates obtained by an enrichment technique, four isolates showed a great potential to degrade hexadecane. The strain MSIC01, which was identified by 16S rRNA gene sequencing as Acinetobacter sp., showed the best performance in degrading this hydrocarbon, being capable of completely degrading 1% (v/v) hexadecane within 48 h without releasing biosurfactants. Its hydrophobic surface probably justifies its potential to degrade high concentrations of hexadecane. Thus, the sediments from the studied mangrove harbour bacterial communities that are able to use oil as a carbon source, which is a particularly interesting feature due to the risk of oil spills in coastal areas. Moreover, Acinetobacter sp. MSIC01 emerged as a promising candidate for applications in bioremediation of contaminated mangrove sediments.
Assuntos
Acinetobacter/crescimento & desenvolvimento , Alcanos/metabolismo , Sedimentos Geológicos/microbiologia , Poluentes Químicos da Água/metabolismo , Acinetobacter/isolamento & purificação , Acinetobacter/metabolismo , Alcanos/análise , Biodegradação Ambiental , Sedimentos Geológicos/química , Poluição por Petróleo , Poluentes Químicos da Água/análise , Áreas AlagadasRESUMO
BACKGROUND: Nosocomial bloodstream infections (nBSIs) are an important cause of morbidity and mortality and are the most frequent type of nosocomial infection in pediatric patients. METHODS: We identified the predominant pathogens and antimicrobial susceptibilities of nosocomial bloodstream isolates in pediatric patients (≤16 years of age) in the Brazilian Prospective Surveillance for nBSIs at 16 hospitals from 12 June 2007 to 31 March 2010 (Br SCOPE project). RESULTS: In our study a total of 2,563 cases of nBSI were reported by hospitals participating in the Br SCOPE project. Among these, 342 clinically significant episodes of BSI were identified in pediatric patients (≤16 years of age). Ninety-six percent of BSIs were monomicrobial. Gram-negative organisms caused 49.0% of these BSIs, Gram-positive organisms caused 42.6%, and fungi caused 8.4%. The most common pathogens were Coagulase-negative staphylococci (CoNS) (21.3%), Klebsiella spp. (15.7%), Staphylococcus aureus (10.6%), and Acinetobacter spp. (9.2%). The crude mortality was 21.6% (74 of 342). Forty-five percent of nBSIs occurred in a pediatric or neonatal intensive-care unit (ICU). The most frequent underlying conditions were malignancy, in 95 patients (27.8%). Among the potential factors predisposing patients to BSI, central venous catheters were the most frequent (66.4%). Methicillin resistance was detected in 37 S. aureus isolates (27.1%). Of the Klebsiella spp. isolates, 43.2% were resistant to ceftriaxone. Of the Acinetobacter spp. and Pseudomonas aeruginosa isolates, 42.9% and 21.4%, respectively, were resistant to imipenem. CONCLUSIONS: In our multicenter study, we found a high mortality and a large proportion of gram-negative bacilli with elevated levels of resistance in pediatric patients.
Assuntos
Bacteriemia/epidemiologia , Infecção Hospitalar/epidemiologia , Infecções por Bactérias Gram-Negativas/epidemiologia , Acinetobacter/efeitos dos fármacos , Acinetobacter/crescimento & desenvolvimento , Antibacterianos/uso terapêutico , Bacteriemia/tratamento farmacológico , Bacteriemia/microbiologia , Bacteriemia/mortalidade , Brasil/epidemiologia , Criança , Pré-Escolar , Infecção Hospitalar/tratamento farmacológico , Infecção Hospitalar/microbiologia , Infecção Hospitalar/mortalidade , Monitoramento Epidemiológico , Feminino , Infecções por Bactérias Gram-Negativas/tratamento farmacológico , Infecções por Bactérias Gram-Negativas/microbiologia , Infecções por Bactérias Gram-Negativas/mortalidade , Humanos , Lactente , Recém-Nascido , Unidades de Terapia Intensiva Neonatal , Klebsiella/efeitos dos fármacos , Klebsiella/crescimento & desenvolvimento , Masculino , Staphylococcus/efeitos dos fármacos , Staphylococcus/crescimento & desenvolvimento , Análise de SobrevidaRESUMO
High copper concentration is toxic for living organisms including humans. Biosorption is a bioremediation technique that can remove copper and other pollutants from aqueous medium and soils, consequently cleaning the environment. The aim of this study was, therefore, to investigate the influence of different copper compounds (Cu(II) as CuCl2; Cu(II) as CuSO4; and Cu(I) as CuCl) on copper bioreduction and biosorption using four copper-resistant bacteria isolated from the rhizosphere of two plants (Avena sativa and Plantago lanceolata) in aqueous matrix. Copper resistance profile, bioreduction, and biosorption after 48 h of incubation were evaluated. The isolates displayed high copper resistance. However, isolate A1 did not grow very well in the CuCl2 and isolate T5 was less resistant to copper in aqueous solutions amended with CuCl (Cu(I)). The best copper source for copper bioreduction and biosorption was CuSO4 and the isolates removed as much as ten times more copper than in aqueous solutions amended with the other copper compounds. Moreover, Cu(I) did not succumb to biosorption, although the microbes were resistant to aqueous solutions of CuCl. In summary, Cu(II) from CuSO4 was furthermost susceptible to bioreduction and biosorption for all isolates. This is an indication that copper contamination of the environment from the use of CuSO4 as an agrochemical is amenable to bioremediation.
Assuntos
Sulfato de Cobre/isolamento & purificação , Cobre/isolamento & purificação , Poluentes Ambientais/isolamento & purificação , Acinetobacter/genética , Acinetobacter/crescimento & desenvolvimento , Acinetobacter/isolamento & purificação , Adsorção , Avena/microbiologia , Biodegradação Ambiental , Biomassa , Farmacorresistência Bacteriana , Oxirredução , Raízes de Plantas/microbiologia , Plantago/microbiologia , Pseudomonas putida/genética , Pseudomonas putida/crescimento & desenvolvimento , Pseudomonas putida/isolamento & purificação , RNA Ribossômico 16S/genética , Rizosfera , Soluções , Stenotrophomonas maltophilia/genética , Stenotrophomonas maltophilia/crescimento & desenvolvimento , Stenotrophomonas maltophilia/isolamento & purificação , ÁguaRESUMO
An L-amino acid oxidase (LAAO) from Crotalus durissus cumanensis venom (CdcLAAO) was purified to homogeneity using a combination of size-exclusion and ion exchange chromatographies. CdcLAAO is a monomeric protein exhibiting an apparent molecular mass of 55 kDa and a calculated pI of 8. Its complete 498-amino-acid sequence was deduced through cDNA and protein sequencing. The enzyme oxidized L-Leu with K(m) and a V(Max) of 9.23 µM and 0.46 µM/min respectively, and exhibited Kcat and a Kcat/K(m) of 1.8 s(-1) and 195 mM(-1)s(-1). CdcLAAO inhibited in a dose-dependent manner the growth of Staphylococcus aureus and Acinetobacter baumannii. The inhibitory effect was more significant on S. aureus, with a Minimal Inhibitory Concentration (MIC) of 8 µg/mL and Minimal Bactericidal Concentration (MBC) of 16 µg/mL, than against A. baumannii, with a MIC of 16 µg/mL and MBC of 32 µg/mL. However, against Escherichia coli CdcLAAO did not show inhibitory capacity at the concentrations tested (2-128 µg/mL). CdcLAAO did not exhibit cytotoxic activity on the mouse myoblast cell line C(2)C(12) and on peripheral blood mononuclear cell (PBMC).
Assuntos
Acinetobacter/efeitos dos fármacos , Antibacterianos/farmacologia , Venenos de Crotalídeos/enzimologia , Crotalus/metabolismo , L-Aminoácido Oxidase/farmacologia , Staphylococcus aureus/efeitos dos fármacos , Acinetobacter/crescimento & desenvolvimento , Acinetobacter/ultraestrutura , Sequência de Aminoácidos , Animais , Antibacterianos/química , Antibacterianos/isolamento & purificação , Linhagem Celular , Sobrevivência Celular/efeitos dos fármacos , Cromatografia Líquida de Alta Pressão , Cromatografia por Troca Iônica , Clonagem Molecular , Venenos de Crotalídeos/genética , DNA Complementar/metabolismo , Humanos , L-Aminoácido Oxidase/química , L-Aminoácido Oxidase/genética , L-Aminoácido Oxidase/isolamento & purificação , Leucócitos Mononucleares/efeitos dos fármacos , Camundongos , Testes de Sensibilidade Microbiana , Dados de Sequência Molecular , Mioblastos/efeitos dos fármacos , Oxirredução , Estrutura Terciária de Proteína , Análise de Sequência de DNA , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz , Staphylococcus aureus/crescimento & desenvolvimento , Staphylococcus aureus/ultraestruturaRESUMO
The genus Acinetobacter has gained importance in recent years due to involvement in serious infections and antimicrobial resistance. Many plants have been evaluated not only for direct antimicrobial activity, but also as resistance modifying agents. The Essential oil of Citrus limon (EOCL) addition at 156.25 µgmL(-1) (MIC/8) sub-inhibitory concentration in the growth medium led to MIC decrease for amikacin, imipenem and meropenem. The Essential oil of Cinnamomum zeylanicum (EOCZ) addition at 78.125 µg mL(-1) (MIC/8) sub-inhibitory concentrations in the growth medium caused drastic MIC reduction of amikacin. Results of combining antibiotics and essential oils had shown us a synergistic effect with both essential oils/amikacin combinations. An additive effect was observed with the combinations of both essential oils and gentamicin. The results of this study suggest that essential oil of C. limon and C. zeylanicum may suppress the growth of Acinetobacter species and could be a source of metabolites with antibacterial modifying activity.
Assuntos
Acinetobacter/efeitos dos fármacos , Antibacterianos/farmacologia , Cinnamomum zeylanicum/química , Citrus/química , Óleos Voláteis/farmacologia , Acinetobacter/crescimento & desenvolvimento , Amicacina/farmacologia , Avaliação Pré-Clínica de Medicamentos/métodos , Farmacorresistência Bacteriana Múltipla/efeitos dos fármacos , Sinergismo Farmacológico , Meropeném , Testes de Sensibilidade Microbiana , Tienamicinas/farmacologiaRESUMO
Cyanuric acid (1,3,5-triazine-2,4,6-triol [OOOT]) is a common biodegradation byproduct of triazinic herbicides, frequently accumulated in soils or water when supplementary carbon sources are absent. A binary bacterial culture able to degrade OOOT was selected through a continuous selection process accomplished in a chemostat fed with a mineral salt (MS) medium containing cyanuric acid as the sole carbon and nitrogen source. By sequence comparison of their 16S rDNA amplicons, bacterial strains were identified as Agrobacterium tumefaciens, and Acinetobacter sp. When the binary culture immobilized in a packed bed reactor (PBR) was fed with MS medium containing OOOT (50 mg L(-1)), its removal efficiencies were about 95%; when it was fed with OOOT plus glucose (120 mg L(-1)) as a supplementary carbon source, its removal efficiencies were closer to 100%. From sessile cells, attached to PBR porous support, or free cells present in the outflowing medium, DNA was extracted and used for Random Amplification of Polymorphic DNA analysis. Electrophoretic patterns obtained were compared to those of pure bacterial strains, a clear predominance of A. tumefaciens in PBR was observed. Although in continuous suspended cell culture, a stable binary community could be maintained, the attachment capability of A. tumefaciens represented a selective advantage over Acinetobacter sp. in the biofilm reactor, favoring its predominance in the porous stone support.
Assuntos
Acinetobacter/crescimento & desenvolvimento , Agrobacterium tumefaciens/crescimento & desenvolvimento , Amidoidrolases/metabolismo , Biofilmes/crescimento & desenvolvimento , Reatores Biológicos/microbiologia , Triazinas/metabolismo , Acinetobacter/classificação , Acinetobacter/enzimologia , Acinetobacter/genética , Agrobacterium tumefaciens/classificação , Agrobacterium tumefaciens/enzimologia , Agrobacterium tumefaciens/genética , Biodegradação Ambiental , Fontes de Energia Bioelétrica , Biotecnologia/métodos , Células Imobilizadas , Meios de Cultura , DNA Bacteriano/genética , Herbicidas/metabolismo , Cinética , Reação em Cadeia da Polimerase , Técnica de Amplificação ao Acaso de DNA PolimórficoRESUMO
Acinetobacter johnsonii A2 isolated from the natural community of Laguna Azul (Andean Mountains at 4,560 m above sea level), Serratia marcescens MF42, Pseudomonas sp. strain MF8 isolated from the planktonic community, and Cytophaga sp. strain MF7 isolated from the benthic community from Laguna Pozuelos (Andean Puna at 3,600 m above sea level) were subjected to UV-B (3,931 J m-2) irradiation. In addition, a marine Pseudomonas putida strain, 2IDINH, and a second Acinetobacter johnsonii strain, ATCC 17909, were used as external controls. Resistance to UV-B and kinetic rates of light-dependent (UV-A [315 to 400 nm] and cool white light [400 to 700 nm]) and -independent reactivation following exposure were determined by measuring the survival (expressed as CFU) and accumulation of cyclobutane pyrimidine dimers (CPD). Significant differences in survival after UV-B irradiation were observed: Acinetobacter johnsonii A2, 48%; Acinetobacter johnsonii ATCC 17909, 20%; Pseudomonas sp. strain MF8, 40%; marine Pseudomonas putida strain 2IDINH, 12%; Cytophaga sp. strain MF7, 20%; and Serratia marcescens, 21%. Most bacteria exhibited little DNA damage (between 40 and 80 CPD/Mb), except for the benthic isolate Cytophaga sp. strain MF7 (400 CPD/Mb) and Acinetobacter johnsonii ATCC 17909 (160 CPD/Mb). The recovery strategies through dark and light repair were different in all strains. The most efficient in recovering were both Acinetobacter johnsonii A2 and Cytophaga sp. strain MF7; Serratia marcescens MF42 showed intermediate recovery, and in both Pseudomonas strains, recovery was essentially zero. The UV-B responses and recovery abilities of the different bacteria were consistent with the irradiation levels in their native environment.
Assuntos
Altitude , Reparo do DNA , Água Doce/microbiologia , Bactérias Gram-Negativas/efeitos da radiação , Raios Ultravioleta/efeitos adversos , Acinetobacter/crescimento & desenvolvimento , Acinetobacter/isolamento & purificação , Acinetobacter/efeitos da radiação , Contagem de Colônia Microbiana , Cytophaga/crescimento & desenvolvimento , Cytophaga/isolamento & purificação , Cytophaga/efeitos da radiação , Dano ao DNA , Ecossistema , Bactérias Gram-Negativas/classificação , Bactérias Gram-Negativas/crescimento & desenvolvimento , Bactérias Gram-Negativas/isolamento & purificação , Pseudomonas/crescimento & desenvolvimento , Pseudomonas/isolamento & purificação , Pseudomonas/efeitos da radiação , Tolerância a Radiação , Serratia marcescens/isolamento & purificação , Serratia marcescens/efeitos da radiação , Luz SolarRESUMO
Isolation of most ultraviolet B (UV-B)-resistant culturable bacteria that occur in the habitat of Laguna Azul, a high-altitude wetland [4554 m above sea level (asl)] from the Northwestern Argentinean Andes, was carried out by culture-based methods. Water from this environment was exposed to UV-B radiation under laboratory conditions during 36 h, at an irradiance of 4.94 W/m2. It was found that the total number of bacteria in water samples decreased; however, most of the community survived long-term irradiation (312 nm) (53.3 kJ/m2). The percentage of bacteria belonging to dominant species did not vary significantly, depending on the number of UV irradiation doses. The most resistant microbes in the culturable community were Gram-positive pigmented species (Bacillus megaterium [endospores and/or vegetative cells], Staphylococcus saprophyticus, and Nocardia sp.). Only one Gram-negative bacterium could be cultivated (Acinetobacter johnsonii). Nocardia sp. that survived doses of 3201 kJ/m2 were the most resistant bacteria to UV-B treatment. This study is the first report on UV-B resistance of a microbial community isolated from high-altitude extreme environments, and proposes a method for direct isolation of UV-B-resistant bacteria from extreme irradiated environments.
Assuntos
Acinetobacter/efeitos da radiação , Altitude , Água Doce/microbiologia , Bactérias Gram-Positivas/efeitos da radiação , Tolerância a Radiação , Raios Ultravioleta , Acinetobacter/classificação , Acinetobacter/genética , Acinetobacter/crescimento & desenvolvimento , Meios de Cultura , Ecossistema , Bactérias Gram-Positivas/classificação , Bactérias Gram-Positivas/genética , Bactérias Gram-Positivas/crescimento & desenvolvimento , Dados de Sequência Molecular , Pigmentos Biológicos/metabolismo , Análise de Sequência de DNARESUMO
Marigold flowers are the main natural source of xanthophylls, and marigold saponified extract is used as an additive in several food and pharmaceutical industries. In this work, the use of a solid-state fermentation (ensilage) process for increasing the yield of xanthophylls extracted from fermented marigold flowers was examined. The process consisted of a mixed culture of three microorganisms (Flavobacterium IIb, Acinetobacter anitratus, and Rhizopus nigricans), part of the normal microbiota associated with the marigold flower. These microorganisms had been previously isolated, and were identified as relevant for the ensilage process due to their capacity to produce cellulolytic enzymes. Based on experimental design strategies, optimum operation values were determined for aeration, moisture, agitation, and marigold-to-inoculum ratio in the proposed solid-state fermentation equipment, leading to a xanthophylls yield of 17.8-g/kg dry weight. The optimum achieved represents a 65% increase with respect to the control. HPLC analysis indicated conservation of extracted oleoresin. Based on the experimental results, interactions were identified that could be associated with the heat and mass-transfer reactions taking place within the bioreactor. The insight gained allows conditions that limit growth and metabolic activity to be avoided.
Assuntos
Biotecnologia/métodos , Extratos Vegetais/isolamento & purificação , Tagetes/química , Xantofilas/isolamento & purificação , Acinetobacter/crescimento & desenvolvimento , Acinetobacter/isolamento & purificação , Acinetobacter/metabolismo , Reatores Biológicos , Fermentação , Flavobacterium/crescimento & desenvolvimento , Flavobacterium/isolamento & purificação , Flavobacterium/metabolismo , Extratos Vegetais/química , Rhizopus/crescimento & desenvolvimento , Rhizopus/isolamento & purificação , Rhizopus/metabolismo , Tagetes/microbiologia , Xantofilas/análiseRESUMO
The toxic benthic dinoflagellate Ostreopsis lenticularis hosts a variety of symbiont bacterial flora. Laboratory cultured Ostreopsis clones require the presence of symbiotic Pseudomonas/Alteromonas bacterial strains for growth and toxicity development. Three culturable bacterial strains associated with Ostreopsis were identified as Pseudomonas/Alteromonas strain 1, Pseudomonas/Alteromonas strain 2 and Acinetobacter. Denaturing gradient gel electrophoresis (DGGE) analyses of extracted Ostreopsis associated bacterial DNAs indicated that there were three culturable and four non-culturable associated bacterial strains. The results presented here are the first report of the presence of unculturable bacterial symbionts in a toxic benthic dinoflagellate. Ostreopsis lost toxicity when exposed to elevated temperatures in the field and laboratory culture and subsequently recovered toxicity at reduced temperatures. Ostreopsis associated culturable Pseudomonas/Alteromonas bacterial strains were significantly reduced in dinoflagellate cultures exposed to elevated temperatures. The decreased toxicity of O. lenticularis exposed to elevated temperatures and their subsequent recovery of toxicity in periods of reduced thermal stress may have resulted from the effects of elevated temperature on the spectrum of culturable and unculturable bacterial species interacting with their Ostreopsis host.
Assuntos
Bactérias/crescimento & desenvolvimento , Dinoflagellida/microbiologia , Simbiose/fisiologia , Acinetobacter/genética , Acinetobacter/crescimento & desenvolvimento , Acinetobacter/isolamento & purificação , Adaptação Fisiológica , Alteromonas/genética , Alteromonas/crescimento & desenvolvimento , Alteromonas/isolamento & purificação , Animais , Bactérias/classificação , Bactérias/genética , Bactérias/isolamento & purificação , Técnicas Bacteriológicas , DNA Bacteriano/genética , DNA Bacteriano/isolamento & purificação , Interações Hospedeiro-Parasita , Toxinas Marinhas/biossíntese , Toxinas Marinhas/toxicidade , Pseudomonas/genética , Pseudomonas/crescimento & desenvolvimento , Pseudomonas/isolamento & purificação , Especificidade da Espécie , Microbiologia da ÁguaRESUMO
Quorum sensing is a widespread regulatory mechanism among Gram-negative bacteria. In this study, Acinetobacter strains were assayed for the presence of quorum sensing signal molecules capable of activating N-acylhomoserine lactone biosensors. By using an Agrobacterium tumefaciens reporter strain it was shown that all the cultures produced two to four detectable signal molecules with different chromatographic patterns. In A. calcoaceticus BD413 supernatants four compounds were detected in a time-dependent manner, and maximal activity was reached at stationary phase. The number of signal molecules was dependent on medium composition; typically, cultures in minimal medium displayed one or two more signals, as compared to complex medium. None of the Acinetobacter supematants showed autoinduction activity with an Chromobacterium violaceum reporter strain, neither in direct or competition assays.