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1.
Chemosphere ; 286(Pt 2): 131795, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34371360

RESUMO

Biofilm formation ability of bacteria makes them potential in the field of tannery effluent treatment. However, the hazardous nature of effluent and environmental conditions may disturb the biofilm formation ability of bacteria which ultimately affects their effluent treatment efficiency. Accordingly, we isolated and characterized biofilm-forming bacteria Bacillus vallismortis (MT027009), Bacillus haynesii (MT027008), and Alcaligenes aquatilis (MT027005) from tannery sludge and examined them for biofilm formation under variable environmental conditions. Biofilm formation in tryptic soy broth (TSB) at different incubation times (24-120 h) revealed that the biofilm formation activity of the strain B. haynesii was not affected by incubation time, whereas the increase in biofilm formation was observed in the case of B. vallismortis (28 %) and A. aquatilis (52 %) after 48 h. The medium pH (pH 5.0-9.0) had a limited effect on biofilm formation except in the case of A. aquatilis at pH 5.0 (94 %) and pH 9.0 (80 %). Furthermore, compared to the controls (only TSB), the strains B. vallismortis, B. haynesii, and A. aquatilis showed enhanced biofilm formation in undiluted tannery effluent (28, 33, and 21 %) and 25 mg L-1 Cr(VI) (23 %, 48 % 32 %). The biofilm structure was influenced by Cr(VI) as revealed by scanning electron microscopy (SEM) analysis. The results of Cr(VI) bioreduction studies suggest that bacterial biofilm (60-99 %) has a greater potential to remove Cr(VI) than planktonic cells (43-94 %). The results of the study provide important data on biofilm formation by indigenous bacteria in effluent environment conditions, making them potential isolates for tannery effluent treatment.


Assuntos
Esgotos , Poluentes Químicos da Água , Alcaligenes , Bacillus , Bactérias , Biodegradação Ambiental , Biofilmes , Cromo/análise , Resíduos Industriais/análise , Poluentes Químicos da Água/análise
2.
J Environ Manage ; 294: 113026, 2021 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-34119990

RESUMO

High cost is one of the limiting factors in the industrial production of bioflocculant. Simultaneous preparation of bioflocculant from the contaminants in wastewater was considered as a potential approach to reduce the production cost. In this study, caprolactam was verified as sole feedstock for the growth of strain Alcaligenes faecalis subsp. phenolicus ZY-16 in batch experiments. Chemical analysis showed that the as-prepared MBF-16 consisted of heteropolysaccharides (88.3%) and peptides (9.4%). XPS result indicated the plentiful acylamino, hydroxyl and amino groups in MBF-16, which have an indispensable role in amoxicillin flocculation. The flocculation of amoxicillin can be well stimulated by Freundlich isotherm equation, and the Kf was up to 178.6524 for amoxicillin. The kinetic fitting results proved that the flocculation of amoxicillin by MBF-16 was chemisorbed. This contribution may develop a novel technology for the preparation of bacterial flocculants that can consume toxic substrates (caprolactam) and have potential applications in amoxicillin removal.


Assuntos
Caprolactama , Alcaligenes , Amoxicilina , Floculação , Concentração de Íons de Hidrogênio , Águas Residuárias
3.
J Biosci Bioeng ; 132(3): 293-301, 2021 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-34167861

RESUMO

Autothermal thermophilic aerobic digestion (ATAD) is used to treat human excreta hygienically. We previously reported a unique full-scale ATAD, showing distinctive bacterial community transitions and producing high-nitrogen-content liquid fertilizer; nevertheless, the mechanism remains unclear. One hypothesis involves using a gas-inducing (GI) agitator. We designed a lab-scale GI system and compared it with a disk-turbine (DT) agitator system by mimicking the temperature shift of full-scale ATAD. The agitation system and its agitation speed greatly affected physicochemical properties and bacterial community structure. GI system at 1000 rpm (GI1000; high total carbon removal efficiency, 88.3%), with few nitrifying and denitrifying bacteria, maintained a high ammoniacal nitrogen concentration and had more shared operational taxonomic units related to Acinetobacter sp., Arcobacter sp., and Longimicrobium sp. with the full-scale ATAD compared with the GI system at 490 rpm and DT system at 1000 rpm (DT1000). Furthermore, DT1000, with a high abundance of nitrifying and denitrifying bacteria such as Alcaligenes aquatilis and Pseudomonas caeni, removed 94.7% total nitrogen with 71.9% total carbon removal efficiency. These results suggested that shear stress and oxygen supply system would change the bacterial community structure, thus affected ATAD performances. Consequently, it is possible that ATAD can be applied for not only production of highly nitrogen-containing liquid fertilizer but also extremely nitrogen removal of wastewater.


Assuntos
Nitrogênio , Esgotos , Alcaligenes , Biodegradação Ambiental , Reatores Biológicos , Digestão , Humanos , Nitrogênio/análise , Oxigênio , Pseudomonas , Eliminação de Resíduos Líquidos
4.
Inorg Chem ; 60(10): 7168-7179, 2021 May 17.
Artigo em Inglês | MEDLINE | ID: mdl-33900072

RESUMO

In this study, we report the synthesis and characterization of [Fe(T1Et4iPrIP)(2-OH-AP)(OTf)](OTf) (2), [Fe(T1Et4iPrIP)(2-O-AP)](OTf) (3), and [Fe(T1Et4iPrIP)(DMF)3](OTf)3 (4) (T1Et4iPrIP = tris(1-ethyl-4-isopropyl-imidazolyl)phosphine; 2-OH-AP = 2-hydroxyacetophenone, and 2-O-AP- = monodeprotonated 2-hydroxyacetophenone). Both 2 and 3 serve as model complexes for the enzyme-substrate adduct for the nonheme enzyme 2,4'-dihydroacetophenone (DHAP) dioxygenase or DAD, while 4 serves as a model for the ferric form of DAD. Complexes 2-4 have been characterized by X-ray crystallography which reveals T1Et4iPrIP to bind iron in a tridentate fashion. Complex 2 additionally contains a bidentate 2-OH-AP ligand and a monodentate triflate ligand yielding distorted octahedral geometry, while 3 possesses a bidentate 2-O-AP- ligand and exhibits distorted trigonal bipyramidal geometry (τ = 0.56). Complex 4 displays distorted octahedral geometry with 3 DMF ligands completing the ligand set. The UV-vis spectrum of 2 matches more closely to the DAD-substrate spectrum than 3, and therefore, it is believed that the substrate for DAD is bound in the protonated form. TD-DFT studies indicate that visible absorption bands for 2 and 3 are due to MLCT bands. Complexes 2 and 3 are capable of oxidizing the coordinated substrate mimics in a stoichiometric and catalytic fashion in the presence of O2. Complex 4 does not convert 2-OH-AP to products under the same catalytic conditions; however, it becomes anaerobically reduced in the presence of 2 equiv 2-OH-AP to 2.


Assuntos
Materiais Biomiméticos/metabolismo , Dioxigenases/metabolismo , Compostos de Ferro/metabolismo , Alcaligenes/enzimologia , Materiais Biomiméticos/química , Teoria da Densidade Funcional , Dioxigenases/química , Compostos de Ferro/síntese química , Compostos de Ferro/química , Modelos Moleculares , Estrutura Molecular
5.
Molecules ; 26(9)2021 Apr 22.
Artigo em Inglês | MEDLINE | ID: mdl-33922162

RESUMO

The present study was aimed to evaluate the suitability of agro-wastes and crude vegetable oils for the cost-effective production of poly-ß-hydroxybutyrate (PHB), to evaluate growth kinetics and PHB production in Alcaligenes faecalis RZS4 and Pseudomonas sp. RZS1 with these carbon substrates and to study the biodegradation of PHB accumulated by these cultures. Alcaligenes faecalis RZS4 and Pseudomonas sp. RZS1 accumulates higher amounts of PHB corn (79.90% of dry cell mass) and rice straw (66.22% of dry cell mass) medium respectively. The kinetic model suggests that the Pseudomonas sp. RZS1 follows the Monod model more closely than A. faecalis RZS4. Both the cultures degrade their PHB extract under the influence of PHB depolymerase. Corn waste and rice straw appear as the best and cost-effective substrates for the sustainable production of PHB from Alcaligenes faecalis RZS4 and Pseudomonas sp. RZS1. The biopolymer accumulated by these organisms is biodegradable in nature. The agro-wastes and crude vegetable oils are good and low-cost sources of nutrients for the growth and production of PHB and other metabolites. Their use would lower the production cost of PHB and the low-cost production will reduce the sailing price of PHB-based products. This would promote the large-scale commercialization and popularization of PHB as an ecofriendly bioplastic/biopolymer.


Assuntos
Agricultura , Alcaligenes/metabolismo , Biopolímeros/biossíntese , Fermentação , Pseudomonas/metabolismo , Resíduos , Biodegradação Ambiental , Biomassa , Biopolímeros/química , Biopolímeros/isolamento & purificação , Cinética , Plásticos/química , Análise Espectral
6.
Bioresour Technol ; 327: 124785, 2021 May.
Artigo em Inglês | MEDLINE | ID: mdl-33582520

RESUMO

Aiming at the accumulation of NO2--N and N2O during denitrification process, this work focused to improve the denitrification performance by Pd-Fe embedded multi-walled carbon nanotubes (MWCNTs). The main conclusions were as follows: 30 mg/L Pd-Fe/MWCNTs have shown an excellent promotion on denitrification (completely TN removal at 36 h). Meanwhile, enzyme activity results indicated that the generation of NO2--N, NH4+-N by Pd-Fe/MWCNTs led the occur of short-cut denitrification by increasing 203.9% the nitrite reductase activity. Furthermore, electrochemical results and index correlation analysis confirmed that the electron exchange capacity (1.401 mmol eg-1) of Pd-Fe/MWCNTs was positively related to nitrite reductase activity, indicating its crucial role in electron transport activity (0.46 µg O2/(protein·min) at 24 h) during denitrification process by Pd-Fe/MWCNTs played a role of chemical reductant and redox mediator.


Assuntos
Alcaligenes , Nanotubos de Carbono , Desnitrificação , Transporte de Elétrons , Oxirredução
7.
Microb Pathog ; 150: 104734, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-33429050

RESUMO

Saffron (Crocus sativus L.) is an important plant in medicine. The Kashmir Valley (J&K, India) is one of the world's largest and finest saffron producing regions. However, over the past decade, there has been a strong declining trend in saffron production in this area. Plant Growth Promoting Rhizobacteria (PGPR) are free living soil bacteria that have ability to colonize the surfaces of the roots and ability to boost plant growth and development either directly or indirectly. Using the efficient PGPR as a bio-inoculant is another sustainable agricultural practice to improve soil health, grain yield quality, and biodiversity conservation. In the present study, a total of 13 bacterial strains were isolated from rhizospheric soil of saffron during the flowering stage of the tubers and were evaluated for various plant growth promoting characteristics under in vitro conditions such as the solubilization of phosphate, production of indole acetic acid, siderophore, hydrocyanic acid, and ammonia production and antagonism by dual culture test against Sclerotium rolfsii and Fusarium oxysporum. All the isolates were further tested for the production of hydrolytic enzymes such as protease, lipase, amylase, cellulase, and chitinase. The maximum proportions of bacterial isolates were gram-negative bacilli. About 77% of the bacterial isolates showed IAA production, 46% exhibited phosphate solubilization, 46% siderophore, 61% HCN, 100% ammonia production, 69% isolates showed protease activity, 62% lipase, 46% amylase, 85% cellulase, and 39% showed chitinase activity. Three isolates viz., AIS-3, AIS-8 and AIS-10 were found to have the most plant growth properties and effectively control the growth of Sclerotium rolfsii and Fusarium oxysporum. The bacterial isolates were identified as Brevibacterium frigoritolerans (AIS-3), Alcaligenes faecalis subsp. Phenolicus (AIS-8) and Bacillus aryabhattai (AIS-10) respectively by 16S rRNA sequence analysis. Therefore, these isolated rhizobacterial strains could be a promising source of plant growth stimulants to increase cormlets growth and increase saffron production.


Assuntos
Crocus , Rizosfera , Alcaligenes , Antifúngicos , Bacillus , Basidiomycota , Fusarium , Índia , Raízes de Plantas , RNA Ribossômico 16S/genética , Microbiologia do Solo
8.
Appl Biochem Biotechnol ; 193(2): 417-429, 2021 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-33015743

RESUMO

A rapid and reliable method for the determination of aldol condensation activity of threonine aldolases (TAs) toward aldehydes and glycine was developed. This 2,4-dinitrophenylhydrazine (DNPH) method has high sensitivity and low background disturbance and can be spectrophotometrically measured for high-throughput screening and characterization of TAs. For 4-methylsulfonyl benzaldehyde (MSB), the maximum absorbance peak was observed at around 485 nm. Site-directed saturation mutagenesis libraries of D-threonine aldolase from Alcaligenes xylosoxidans CGMCC 1.4257 (AxDTA) was constructed and screened with this DNPH method for increased aldol activity toward MSB. Two beneficial variants AxDTAD321C and AxDTAN101G were identified. Substrate specificity of AxDTA and variants toward nineteen aldehydes with different substituents was facilely characterized employing this DNPH method. Furthermore, AxDTA variants displayed enhanced catalytic performance and selectivity in aldol reaction. Consequently, our study provides a rapid screening and characterization method for TAs with potential applications in preparation of chiral ß-hydroxy-α-amino acids.


Assuntos
Alcaligenes , Proteínas de Bactérias , Evolução Molecular Direcionada , Glicina Hidroximetiltransferase , Alcaligenes/enzimologia , Alcaligenes/genética , Proteínas de Bactérias/biossíntese , Proteínas de Bactérias/química , Proteínas de Bactérias/genética , Glicina Hidroximetiltransferase/biossíntese , Glicina Hidroximetiltransferase/química , Glicina Hidroximetiltransferase/genética
9.
FEBS J ; 288(1): 262-280, 2021 01.
Artigo em Inglês | MEDLINE | ID: mdl-32255260

RESUMO

Cu-containing nitrite reductases that convert NO2 - to NO are critical enzymes in nitrogen-based energy metabolism. Among organisms in the order Rhizobiales, we have identified two copies of nirK, one encoding a new class of 4-domain CuNiR that has both cytochrome and cupredoxin domains fused at the N terminus and the other, a classical 2-domain CuNiR (Br2D NiR). We report the first enzymatic studies of a novel 4-domain CuNiR from Bradyrhizobium sp. ORS 375 (BrNiR), its genetically engineered 3- and 2-domain variants, and Br2D NiR revealing up to ~ 500-fold difference in catalytic efficiency in comparison with classical 2-domain CuNiRs. Contrary to the expectation that tethering would enhance electron delivery by restricting the conformational search by having a self-contained donor-acceptor system, we demonstrate that 4-domain BrNiR utilizes N-terminal tethering for downregulating enzymatic activity instead. Both Br2D NiR and an engineered 2-domain variant of BrNiR (Δ(Cytc-Cup) BrNiR) have 3 to 5% NiR activity compared to the well-characterized 2-domain CuNiRs from Alcaligenes xylosoxidans (AxNiR) and Achromobacter cycloclastes (AcNiR). Structural comparison of Δ(Cytc-Cup) BrNiR and Br2D NiR with classical 2-domain AxNiR and AcNiR reveals structural differences of the proton transfer pathway that could be responsible for the lowering of activity. Our study provides insights into unique structural and functional characteristics of naturally occurring 4-domain CuNiR and its engineered 3- and 2-domain variants. The reverse protein engineering approach utilized here has shed light onto the broader question of the evolution of transient encounter complexes and tethered electron transfer complexes. ENZYME: Copper-containing nitrite reductase (CuNiR) (EC 1.7.2.1). DATABASE: The atomic coordinate and structure factor of Δ(Cytc-Cup) BrNiR and Br2D NiR have been deposited in the Protein Data Bank (http://www.rcsb.org/) under the accession code 6THE and 6THF, respectively.


Assuntos
Achromobacter cycloclastes/química , Alcaligenes/química , Proteínas de Bactérias/química , Bradyrhizobium/química , Cobre/química , Nitrito Redutases/química , Achromobacter cycloclastes/enzimologia , Achromobacter cycloclastes/genética , Alcaligenes/enzimologia , Alcaligenes/genética , Sequência de Aminoácidos , Azurina/química , Azurina/genética , Azurina/metabolismo , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Bradyrhizobium/enzimologia , Bradyrhizobium/genética , Domínio Catalítico , Clonagem Molecular , Cobre/metabolismo , Cristalografia por Raios X , Citocromos c/química , Citocromos c/genética , Citocromos c/metabolismo , Elétrons , Escherichia coli/genética , Escherichia coli/metabolismo , Expressão Gênica , Vetores Genéticos/química , Vetores Genéticos/metabolismo , Modelos Moleculares , Nitrito Redutases/genética , Nitrito Redutases/metabolismo , Ligação Proteica , Conformação Proteica em alfa-Hélice , Conformação Proteica em Folha beta , Engenharia de Proteínas/métodos , Domínios e Motivos de Interação entre Proteínas , Prótons , Proteínas Recombinantes/química , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo , Genética Reversa/métodos , Alinhamento de Sequência , Homologia de Sequência de Aminoácidos , Especificidade por Substrato
10.
Inorg Chem ; 59(19): 14162-14170, 2020 Oct 05.
Artigo em Inglês | MEDLINE | ID: mdl-32970420

RESUMO

Hydroxylamine (NH2OH or HA) is a redox-active nitrogen oxide that occurs as a toxic intermediate in the oxidation of ammonium by nitrifying and methanotrophic bacteria. Within ammonium containing environments, HA is generated by ammonia monooxygenase (nitrifiers) or methane monooxygenase (methanotrophs). Subsequent oxidation of HA is catalyzed by heme proteins, including cytochromes P460 and multiheme hydroxylamine oxidoreductases, the former contributing to emissions of N2O, an ozone-depleting greenhouse gas. A heme-HA complex is also a proposed intermediate in the reduction of nitrite to ammonia by cytochrome c nitrite reductase. Despite the importance of heme-HA complexes within the biogeochemical nitrogen cycle, fundamental aspects of their coordination chemistry remain unknown, including the effect of the Fe redox state on heme-HA affinity, kinetics, and spectroscopy. Using stopped-flow UV-vis and resonance Raman spectroscopy, we investigated HA complexes of the L16G distal pocket variant of Alcaligenes xylosoxidans cytochrome c'-α (L16G AxCP-α), a pentacoordinate c-type cytochrome that we show binds HA in its Fe(III) (Kd ∼ 2.5 mM) and Fe(II) (Kd = 0.0345 mM) states. The ∼70-fold higher HA affinity of the Fe(II) state is due mostly to its lower koff value (0.0994 s-1 vs 11 s-1), whereas kon values for Fe(II) (2880 M-1 s-1) and Fe(III) (4300 M-1 s-1) redox states are relatively similar. A comparison of the HA and imidazole affinities of L16G AxCP-α was also used to predict the influence of Fe redox state on HA binding to other proteins. Although HA complexes of L16G AxCP-α decompose via redox reactions, the lifetime of the Fe(II)HA complex was prolonged in the presence of excess reductant. Spectroscopic parameters determined for the Fe(II)HA complex include the N-O stretching vibration of the NH2OH ligand, ν(N-O) = 906 cm-1. Overall, the kinetic trends and spectroscopic benchmarks from this study provide a foundation for future investigations of heme-HA reaction mechanisms.


Assuntos
Citocromos c/química , Heme/química , Hidroxilamina/química , Ferro/química , Análise Espectral , Alcaligenes/enzimologia , Citocromos c/metabolismo , Cinética , Oxirredução
11.
Dokl Biochem Biophys ; 492(1): 117-120, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-32632586

RESUMO

We studied the effect of acrylamide on the content of intracellular ATP in the cells of bacteria of the genera Rhodococcus and Alcaligenes, the luminescence of the genetically engineered strain Escherichia coli K12 TG1 (pXen7), and the survival of bacteria of various systematic groups. According to the level of decrease in the concentration of intracellular ATP, it was found that the strain with lower amidase activity (R. erythropolis 6-21) and Gram-negative proteobacteria A. faecalis 2 were the most sensitive to acrylamide after a 20-min exposure, while the strain R. ruber gt 1 was stable, having a high nitrile hydratase activity in combination with a low amidase activity. EC50 of acrylamide for 2 h was 7.1 g/L for E. coli K12 TG1 (pXen7). Acrylamide at a concentration of 10-20 mM added to the culture medium led to a slight decrease in the number of CFUs of Rhodococcus, A. faecalis 2, and E. coli compared to the control. At an acrylamide concentration of 250 mM, from 0.016 to 0.116% of viable bacterial cells remained, and a solution of 500 mM and higher inhibited the growth of the majority of the studied strains. The results confirm that acrylamide is much less toxic to prokaryotes than to eukaryotes.


Assuntos
Acrilamida/toxicidade , Trifosfato de Adenosina/metabolismo , Alcaligenes/crescimento & desenvolvimento , Amidoidrolases/metabolismo , Escherichia coli/crescimento & desenvolvimento , Hidroliases/metabolismo , Rhodococcus/crescimento & desenvolvimento , Alcaligenes/efeitos dos fármacos , Escherichia coli/efeitos dos fármacos , Rhodococcus/efeitos dos fármacos
12.
Antonie Van Leeuwenhoek ; 113(7): 889-905, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32152804

RESUMO

Intensification of sodic soil due to increasing pH is an emerging environmental issue. The present study aimed to isolate and characterise alkaline stress-tolerant and plant growth-promoting bacterial strains from moderately alkaline soil (pH 8-9), strongly alkaline soil (pH 9-10), and very strongly alkaline soil (> 10). Total 68 bacteria were isolated, and screened for multiple plant growth promoting (PGP) attributes. Out of total, 42 isolates demonstrating at least three plant growth promoting PGP traits selected for further assays. Then out of 42, 15 bacterial isolates were selected based on enhanced maize plant growth under greenhouse experiment, and 16S rRNA gene sequencing revealed Bacillus spp. as a dominant genus. Furthermore, based on improved seed germination percentage and biomass of maize (Zea mays L.) under alkaline stress conditions Alcaligenes sp. NBRI NB2.5, Bacillus sp. NBRI YE1.3, and Bacillus sp. NBRI YN4.4 bacterial strains were selected, and evaluated for growth-promotion and alkaline stress amelioration under greenhouse condition. Amongst the selected 3 plant growth promoting rhizobacterial (PGPR) strains, Bacillus sp. NBRI YN4.4 significantly improved the photosynthetic pigments and soluble sugar content, and decreased proline level in inoculated maize plants as compared to uninoculated control under stress conditions. Moreover, significantly enhanced soil enzymes such as dehydrogenase, alkaline phosphatase and betaglucosidase due to inoculation of Bacillus sp. NBRI YN4.4 in maize plants grown in alkaline soil attributes to its role in improving the soil health. Therefore, alkaline stress-tolerant PGPR NBRI YN4.4 can be useful for developing strategies for the reclamation of saline/sodic soils and improving the plant growth and soil health in sustainable manner.


Assuntos
Alcaligenes/fisiologia , Bacillus/fisiologia , Desenvolvimento Vegetal , Zea mays/microbiologia , Aclimatação , Alcaligenes/genética , Alcaligenes/isolamento & purificação , Bacillus/genética , Bacillus/isolamento & purificação , Bactérias/classificação , Bactérias/genética , Biomassa , Concentração de Íons de Hidrogênio , Raízes de Plantas/microbiologia , RNA Ribossômico 16S , Rizosfera , Salinidade , Análise de Sequência de DNA , Solo/química , Microbiologia do Solo , Zea mays/crescimento & desenvolvimento
13.
Arch Microbiol ; 202(6): 1489-1495, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32219483

RESUMO

Antibiotic contamination in environmental matrices is a serious global problem which leads to an increase in the proliferation of antibiotic resistance genes. Amoxicillin is ubiquitous in the environment, but there is hardly any information on the dissipation of amoxicillin by the microbial community. In view of this, the present study focusses on the removal of amoxicillin using amoxicillin-resistant bacteria, Alcaligenes sp. MMA. Bacteria were characterized using antibiotic tests, biochemical and molecular analysis. Alcaligenes sp. MMA was able to remove up to 84% of amoxicillin in 14 days in M9 minimal media, and the degradation products were confirmed using LC-MS/MS, including the benzothiazole, 2-Amino-3-methoxyl benzoic acid, 4-Hydroxy-2-methyl benzoic acid, 5-Amino-2-methylphenol and 3,5-Bis(tert-butyl)-2-hydroxybenzaldehyde, at the end of 14th day which further shows the removal of amoxicillin by the bacterial strain. Differential expression of porins was found in the presence of amoxicillin as a sole source of carbon and energy for the bacterial strain. Molecular interaction using in silico studies were performed which showed the formation of a hydrogen bond between amoxicillin and porins.


Assuntos
Alcaligenes/metabolismo , Amoxicilina/metabolismo , Antibacterianos/metabolismo , Biodegradação Ambiental , Alcaligenes/genética , Cromatografia Líquida , Farmacorresistência Bacteriana/fisiologia , Testes de Sensibilidade Microbiana , Simulação de Acoplamento Molecular , Porinas/biossíntese , Espectrometria de Massas em Tandem
14.
Chem Res Toxicol ; 33(4): 915-932, 2020 04 20.
Artigo em Inglês | MEDLINE | ID: mdl-32138518

RESUMO

Glucan (from Alcaligenes faecalis) is a polymer composed of ß-1,3-linked glucose residues, and it has been addressed in different medical fields, namely in nanotechnology, as a vaccine or a drug delivery system. However, due to their small size, nanomaterials may present new risks and uncertainties. Thus, this work aims to describe the production of glucan nanoparticles (NPs) with two different sizes, and to evaluate the influence of the NPs size on immunotoxicity. Results showed that, immediately after production, glucan NPs presented average sizes of 129.7 ± 2.5 and 355.4 ± 41.0 nm. Glucan NPs of 130 nm presented greater ability to decrease human peripheral blood mononuclear cells and macrophage viability and to induce reactive oxygen species production than glucan NPs of 355 nm. Both NP sizes caused hemolysis and induced a higher metabolic activity in lymphocytes, although the concentration required to observe such effect was lower for the 130 nm glucan NPs. Regarding pro-inflammatory cytokines, only the larger glucan NPs (355 nm) were able to induce the secretion of IL-6 and TNF-α, probably due to their recognition by dectin-1. This higher immunomodulatory effect of the larger NPs was also observed in its ability to stimulate the production of nitric oxide (NO) and IL-1ß. On the contrary, a small amount of Glu 130 NPs inhibited NO production. In conclusion, on the safe-by-design of glucan NPs, the size of the particles should be an important critical quality attribute to guarantee the safety and effectiveness of the nanomedicine.


Assuntos
Morte Celular/efeitos dos fármacos , Glucanos/toxicidade , Leucócitos Mononucleares/efeitos dos fármacos , Nanopartículas/química , Nanopartículas/toxicidade , Alcaligenes/química , Sobrevivência Celular/efeitos dos fármacos , Glucanos/síntese química , Glucanos/química , Humanos , Leucócitos Mononucleares/imunologia , Macrófagos/efeitos dos fármacos , Macrófagos/imunologia , Tamanho da Partícula , Espécies Reativas de Oxigênio/metabolismo
15.
Molecules ; 25(3)2020 Feb 08.
Artigo em Inglês | MEDLINE | ID: mdl-32046287

RESUMO

Methomyl is a broad-spectrum oxime carbamate commonly used to control arthropods, nematodes, flies, and crop pests. However, extensive use of this pesticide in agricultural practices has led to environmental toxicity and human health issues. Oxidation, incineration, adsorption, and microbial degradation methods have been developed to remove insecticidal residues from soil/water environments. Compared with physicochemical methods, biodegradation is considered to be a cost-effective and ecofriendly approach to the removal of pesticide residues. Therefore, micro-organisms have become a key component of the degradation and detoxification of methomyl through catabolic pathways and genetic determinants. Several species of methomyl-degrading bacteria have been isolated and characterized, including Paracoccus, Pseudomonas, Aminobacter, Flavobacterium, Alcaligenes, Bacillus, Serratia, Novosphingobium, and Trametes. The degradation pathways of methomyl and the fate of several metabolites have been investigated. Further in-depth studies based on molecular biology and genetics are needed to elaborate their role in the evolution of novel catabolic pathways and the microbial degradation of methomyl. In this review, we highlight the mechanism of microbial degradation of methomyl along with metabolic pathways and genes/enzymes of different genera.


Assuntos
Inibidores da Colinesterase/metabolismo , Inseticidas/metabolismo , Metomil/metabolismo , Poluentes do Solo/metabolismo , Poluentes Químicos da Água/metabolismo , Adsorção , Alcaligenes/metabolismo , Bacillus/metabolismo , Biodegradação Ambiental , Flavobacterium/metabolismo , Humanos , Incineração/métodos , Redes e Vias Metabólicas/fisiologia , Oxirredução , Paracoccus/metabolismo , Pseudomonas/metabolismo , Serratia/metabolismo , Trametes/metabolismo
16.
Colloids Surf B Biointerfaces ; 188: 110812, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-31981814

RESUMO

Herein, thermophilic lipase QLM from Alcaligenes sp. has been successfully immobilized in bio-based metal-organic frameworks (MOFs) through biomimetic mineralization, using zinc acetate and adenine as metal ion and organic ligand, respectively. The morphology and structure of lipase@Bio-MOF was systematically characterized by scanning electron microcopy (SEM), transmission electron microcopy (TEM), powder X-ray diffraction (PXRD) and Fourier transform infrared spectra (FT-IR). The enzyme loading in immobilized enzyme was measured to be 15.9 % by thermogravimetric analysis (TGA). Further, it was demonstrated to possess favorable catalytic activity and stability under high temperature and alkaline conditions and in the presence of metal ions, using the hydrolysis of p-nitrophenyl caprylate as a model. Finally, the immobilized enzyme was successfully applied in the preparation of biodiesel through the trans-esterification of sunflower oil with methanol, obtaining a conversion of >60 % at a high oil/methanol ratio of 8:1. Meanwhile, it showed excellent recyclability during the biodiesel production, and no changes of morphology and crystal structure were observed after being used for 3 cycles. Overall, the immobilized lipase in bio-based MOFs provided an economically and environmentally viable biocatalyst for the synthesis of biodiesel.


Assuntos
Biocombustíveis , Materiais Biomiméticos/metabolismo , Lipase/metabolismo , Estruturas Metalorgânicas/metabolismo , Alcaligenes/enzimologia , Biocatálise , Materiais Biomiméticos/química , Enzimas Imobilizadas/química , Enzimas Imobilizadas/metabolismo , Lipase/química , Estruturas Metalorgânicas/química , Estrutura Molecular , Tamanho da Partícula , Propriedades de Superfície
17.
Metallomics ; 12(3): 337-345, 2020 03 25.
Artigo em Inglês | MEDLINE | ID: mdl-31956880

RESUMO

Protein oligomers have gained interest, owing to their increased knowledge in cells and promising utilization for future materials. Various proteins have been shown to 3D domain swap, but there has been no domain swapping report on a blue copper protein. Here, we found that azurin from Alcaligenes xylosoxidans oligomerizes by the procedure of 2,2,2-trifluoroethanol addition to Cu(i)-azurin at pH 5.0, lyophilization, and dissolution at pH 7.0, whereas it slightly oligomerizes when using Cu(ii)-azurin. The amount of high order oligomers increased with the addition of Cu(ii) ions to the dissolution process of a similar procedure for apoazurin, indicating that Cu(ii) ions enhance azurin oligomerization. The ratio of the absorbance at 460 nm to that at ∼620 nm of the azurin dimer (Abs460/Abs618 = 0.113) was higher than that of the monomer (Abs460/Abs622 = 0.067) and the EPR A‖ value of the dimer (5.85 mT) was slightly smaller than that of the monomer (5.95 mT), indicating a slightly more rhombic copper coordination for the dimer. The redox potential of the azurin dimer was 342 ± 5 mV vs. NHE, which was 50 mV higher than that of the monomer. According to X-ray crystal analysis, the azurin dimer exhibited a domain-swapped structure, where the N-terminal region containing three ß-strands was exchanged between protomers. The copper coordination structure was tetrahedrally distorted in the azurin dimer, similar to that in the monomer; however, the Cu-O(Gly45) bond length was longer for the dimer (monomer, 2.46-2.59 Å; dimer, 2.98-3.25 Å). These results open the door for designing oligomers of blue copper proteins by domain swapping.


Assuntos
Alcaligenes/química , Azurina/química , Proteínas de Bactérias/química , Cobre/química , Cristalografia por Raios X , Modelos Moleculares , Conformação Proteica , Domínios Proteicos , Multimerização Proteica
18.
Sci Total Environ ; 708: 135063, 2020 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-31810663

RESUMO

The microbial reduction of nitrate in the presence of nanoscale zero-valent iron (nZVI) was evaluated to assess the feasibility of employing nZVI for biological denitrification treatment. The effect of modified nZVI on the growth, metabolism, and denitrification performance of Alcaligenes sp. TB under aerobic conditions was studied. Results showed that Alcaligenes sp. TB with nZVI/Pd had 31.5% increase in nitrate removal and 18.1% decrease in nitrite accumulation within 28 h. nZVI/Pd exhibited less inhibition on the cell growth (OD600 = 0.725), NADH/NAD+ ratio (86% of control), and electron transfer system activity (68.5% of control). In addition, nZVI/Pd decreased the membrane fluidity by increasing the trans/cis isomerization ratio (317.7% of control) to enhance the resistance of nZVI. This study underlines the effects of nZVI/Pd on membrane susceptibility via membrane fatty acid transformation during denitrification and suggests the influence of engineered nanomaterials on denitrification.


Assuntos
Alcaligenes , Desnitrificação , Ferro , Nitratos , Nitritos
19.
PLoS One ; 14(9): e0221574, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31550268

RESUMO

Environmental contamination with hydrocarbons though natural and anthropogenic activities is a serious threat to biodiversity and human health. Microbial bioremediation is considered as the effective means of treating such contamination. This study describes a biosurfactant producing bacterium capable of utilizing crude oil and various hydrocarbons as the sole carbon source. Strain BU33N was isolated from hydrocarbon polluted sediments from the Bizerte coast (northern Tunisia) and was identified as Alcaligenes aquatilis on the basis of 16S rRNA gene sequence analysis. When grown on crude oil and phenanthrene as sole carbon and energy sources, isolate BU33N was able to degrade ~86%, ~56% and 70% of TERHc, n-alkanes and phenanthrene, respectively. The draft genome sequence of the A. aquatilis strain BU33N was assembled into one scaffold of 3,838,299 bp (G+C content of 56.1%). Annotation of the BU33N genome resulted in 3,506 protein-coding genes and 56 rRNA genes. A large repertoire of genes related to the metabolism of aromatic compounds including genes encoding enzymes involved in the complete degradation of benzoate were identified. Also genes associated with resistance to heavy metals such as copper tolerance and cobalt-zinc-cadmium resistance were identified in BU33N. This work provides insight into the genomic basis of biodegradation capabilities and bioremediation/detoxification potential of A. aquatilis BU33N.


Assuntos
Alcaligenes/genética , Alcaligenes/metabolismo , Hidrocarbonetos/metabolismo , Alcaligenes/isolamento & purificação , Biodegradação Ambiental , Poluentes Ambientais/metabolismo , Genoma Bacteriano , Sedimentos Geológicos/microbiologia , Humanos , Redes e Vias Metabólicas/genética , Família Multigênica , Filogenia , Especificidade da Espécie , Tensoativos/metabolismo
20.
Ecotoxicol Environ Saf ; 183: 109507, 2019 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-31386942

RESUMO

Multi-walled carbon nanotubes (MWCNTs) promote biodegradation in water treatment, but the effect of MWCNT on denitrification under aerobic conditions is still unclear. This investigation focused on the denitrification performance of MWCNT and its toxic effects on Alcaligenes sp. TB which showed that 30 mg/L MWCNTs increased NO3- removal efficiency from 84% to 100% and decreased the NO2-and N2O accumulation rates by 36% and 17.5%, respectively. Nitrite reductase and nitrous oxide reductase activities were further increased by 19.5% and 7.5%, respectively. The mechanism demonstrated that electron generation (NADH yield) and electron transportation system activity increased by 14.5% and 104%, respectively. Cell membrane analysis found that MWCNT caused an increase in polyunsaturated fatty acids, which had positive effects on electron transportation and membrane fluidity at a low concentration of 96 mg/kg but caused membrane lipid peroxidation and impaired membrane integrity at a high concentration of 115 mg/L. These findings confirmed that MWCNT affects the activity of Alcaligenes sp. TB and consequently enhances denitrification performance.


Assuntos
Alcaligenes/metabolismo , Desnitrificação/fisiologia , Nanotubos de Carbono , Purificação da Água/métodos , Biodegradação Ambiental , Membrana Celular/efeitos dos fármacos , Membrana Celular/metabolismo , Desnitrificação/efeitos dos fármacos , Transporte de Elétrons , Ácidos Graxos Insaturados/metabolismo , NAD/metabolismo , Nanotubos de Carbono/toxicidade , Nitratos/isolamento & purificação
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