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1.
Chemosphere ; 248: 125983, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-32004887

RESUMO

In this study, derivatives of two common fatty acids in plant root exudates, sodium palmitate and sodium linoleate (sodium aliphatates), were added to an aged Polycyclic aromatic hydrocarbons (PAHs) contaminated soil to estimate their effectiveness in the removal of PAHs. Sodium linoleate was more effective in lowering PAHs and especially high-molecular-weight (4-6 ring) PAHs (HMW-PAHs). Principal coordinates analysis (PCoA) indicates that both amendments led to a shift in the soil bacterial community. Moreover, linear discriminant effect size (LEfSe) analysis demonstrates that the specific PAHs degraders Pseudomonas, Arenimonas, Pseudoxanthomonas and Lysobacter belonging to the γ-proteobacteria and Nocardia and Rhodococcus belonging to the Actinobacteria were the biomarkers of, respectively, sodium linoleate and sodium palmitate amendments. Correlation analysis suggests that four biomarkers in the sodium linoleate amendment treatment from γ-proteobacteria were all highly linearly negatively related to HMW-PAHs residues (p < 0.01) while two biomarkers in the sodium palmitate amendment treatment from Actinobacteria were highly linearly negatively related to LMW-PAHs residues (p < 0.01). Higher removal efficiency of PAHs (especially HMW-PAHs) in the sodium linoleate amendment treatment than in the sodium palmitate amendment treatment might be ascribed to the specific enrichment of microbes from the γ-proteobacteria. The bacterial functional KEGG orthologs (KOs) assigned to PAHs metabolism and functional C23O and C12O genes related to cleavage of the benzene ring were both up-regulated. These results provide new insight into the mechanisms of the two sodium aliphatate amendments in accelerating PAHs biodegradation and have implications for practical application in the remediation of PAHs-contaminated soils.


Assuntos
Recuperação e Remediação Ambiental , Hidrocarbonetos Policíclicos Aromáticos/metabolismo , Microbiologia do Solo , Poluentes do Solo/metabolismo , Actinobacteria/metabolismo , Bactérias/metabolismo , Biodegradação Ambiental , Ácidos Graxos/metabolismo , Gammaproteobacteria/metabolismo , Microbiota , Raízes de Plantas/metabolismo , Hidrocarbonetos Policíclicos Aromáticos/análise , Solo/química , Poluentes do Solo/análise
2.
Nature ; 578(7796): 582-587, 2020 02.
Artigo em Inglês | MEDLINE | ID: mdl-32051588

RESUMO

Addressing the ongoing antibiotic crisis requires the discovery of compounds with novel mechanisms of action that are capable of treating drug-resistant infections1. Many antibiotics are sourced from specialized metabolites produced by bacteria, particularly those of the Actinomycetes family2. Although actinomycete extracts have traditionally been screened using activity-based platforms, this approach has become unfavourable owing to the frequent rediscovery of known compounds. Genome sequencing of actinomycetes reveals an untapped reservoir of biosynthetic gene clusters, but prioritization is required to predict which gene clusters may yield promising new chemical matter2. Here we make use of the phylogeny of biosynthetic genes along with the lack of known resistance determinants to predict divergent members of the glycopeptide family of antibiotics that are likely to possess new biological activities. Using these predictions, we uncovered two members of a new functional class of glycopeptide antibiotics-the known glycopeptide antibiotic complestatin and a newly discovered compound we call corbomycin-that have a novel mode of action. We show that by binding to peptidoglycan, complestatin and corbomycin block the action of autolysins-essential peptidoglycan hydrolases that are required for remodelling of the cell wall during growth. Corbomycin and complestatin have low levels of resistance development and are effective in reducing bacterial burden in a mouse model of skin MRSA infection.


Assuntos
Antibacterianos/farmacologia , Descoberta de Drogas , Peptidoglicano/efeitos dos fármacos , Peptidoglicano/metabolismo , Actinobacteria/química , Actinobacteria/genética , Actinobacteria/metabolismo , Animais , Antibacterianos/química , Vias Biossintéticas/genética , Parede Celular/metabolismo , Clorofenóis/química , Clorofenóis/metabolismo , Clorofenóis/farmacologia , Modelos Animais de Doenças , Resistência Microbiana a Medicamentos/efeitos dos fármacos , Resistência Microbiana a Medicamentos/genética , Feminino , Staphylococcus aureus Resistente à Meticilina/efeitos dos fármacos , Camundongos , Testes de Sensibilidade Microbiana , Família Multigênica , N-Acetil-Muramil-L-Alanina Amidase/antagonistas & inibidores , Peptídeos Cíclicos/química , Peptídeos Cíclicos/metabolismo , Peptídeos Cíclicos/farmacologia , Filogenia , Pele/microbiologia , Infecções Estafilocócicas/microbiologia
3.
Microb Cell Fact ; 19(1): 5, 2020 Jan 09.
Artigo em Inglês | MEDLINE | ID: mdl-31918711

RESUMO

BACKGROUND: Heterologous expression of secondary metabolite gene clusters is used to achieve increased production of desired compounds, activate cryptic gene clusters, manipulate clusters from genetically unamenable strains, obtain natural products from uncultivable species, create new unnatural pathways, etc. Several Streptomyces species are genetically engineered for use as hosts for heterologous expression of gene clusters. S. lividans TK24 is one of the most studied and genetically tractable actinobacteria, which remain untapped. It was therefore important to generate S. lividans chassis strains with clean metabolic backgrounds. RESULTS: In this study, we generated a set of S. lividans chassis strains by deleting endogenous gene clusters and introducing additional φC31 attB loci for site-specific integration of foreign DNA. In addition to the simplified metabolic background, the engineered S. lividans strains had better growth characteristics than the parental strain in liquid production medium. The utility of the developed strains was validated by expressing four secondary metabolite gene clusters responsible for the production of different classes of natural products. Engineered strains were found to be superior to the parental strain in production of heterologous natural products. Furthermore, S. lividans-based strains were better producers of amino acid-based natural products than other tested common hosts. Expression of a Streptomyces albus subsp. chlorinus NRRL B-24108 genomic library in the modified S. lividans ΔYA9 and S. albus Del14 strains resulted in the production of 7 potentially new compounds, only one of which was produced in both strains. CONCLUSION: The constructed S. lividans-based strains are a great complement to the panel of heterologous hosts for actinobacterial secondary metabolite gene expression. The expansion of the number of such engineered strains will contribute to an increased success rate in isolation of new natural products originating from the expression of genomic and metagenomic libraries, thus raising the chance to obtain novel biologically active compounds.


Assuntos
Antibacterianos/biossíntese , Produtos Biológicos , Metabolismo Secundário/genética , Streptomyces lividans/genética , Actinobacteria/genética , Actinobacteria/metabolismo , Antibacterianos/química , Bacteriocinas/biossíntese , Bacteriocinas/química , Produtos Biológicos/química , Produtos Biológicos/metabolismo , Clonagem Molecular , Engenharia Genética/métodos , Família Multigênica , Peptídeos Cíclicos/biossíntese , Peptídeos Cíclicos/química , Streptomyces lividans/metabolismo , Tunicamicina/biossíntese , Tunicamicina/química
4.
J Agric Food Chem ; 68(1): 17-32, 2020 Jan 08.
Artigo em Inglês | MEDLINE | ID: mdl-31809036

RESUMO

Weeds had caused significant loss for crop production in the process of agriculture. Herbicides have played an important role in securing crop production. However, the high reliance on herbicides has led to environmental issues as well as the evolution of herbicide resistance. Thus, there is an urgent need for new herbicides with safer toxicological profiles and novel modes of action. Actinomycetes produce very diverse bioactive compounds, of which some show potent biopesticidal activity. The herbicidal secondary metabolites from actinomycetes can be classified into several groups, such as amino acids, peptides, nucleosides, macrolides, lactones, amide, amines, etc., some of which have been successfully developed as commercial herbicides. The structure diversity and evolved biological activity of secondary metabolites from actinomycetes can offer opportunities for the development of both directly used bioherbicides and synthetic herbicides with new target sites, and thus, this review focuses on the structure, herbicidal activity, and modes of action of secondary metabolites from actinomycetes.


Assuntos
Actinobacteria/química , Herbicidas/química , Herbicidas/farmacologia , Actinobacteria/metabolismo , Descoberta de Drogas , Herbicidas/metabolismo , Plantas Daninhas/efeitos dos fármacos , Plantas Daninhas/crescimento & desenvolvimento , Metabolismo Secundário , Controle de Plantas Daninhas
5.
J Basic Microbiol ; 60(1): 22-26, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31692013

RESUMO

Metals are among the most prevalent pollutants released into the environment. For these reasons, the use of biomarkers for environmental monitoring of individuals and populations exposed to metal pollution has gained considerable attention, offering fast and sensitive detection of chemical stress in organisms. There are different metal resistance genes in bacteria that can be used as biomarkers, including cation diffusion facilitators carrying metal ions; the prototype is the cobalt-zinc-cadmium transporter (czcD). The present study reports the expression changes in the czcD gene in Bacillus megaterium and Microbacterium liquefaciens under nickel and vanadium exposure by real-time polymerase chain reaction. The nickel-vanadium-resistant strains of B. megaterium and M. liquefaciens used in this study were isolated from mine tailings in Guanajuato, Mexico. The czcD gene showed high expression under exposure to 200 ppm of Ni and 200 ppm of V during the logarithmic growth phase of M. liquefaciens in PHGII liquid media. In contrast, no changes were observed in B. megaterium during logarithmic and stationary growth, perhaps due to the gene having differential expression during the growth phases. The expression profiles obtained for czcD show the possibility of using this gene from M. liquefaciens as a biomarker of nickel and vanadium pollution in microorganisms.


Assuntos
Actinobacteria/genética , Bacillus megaterium/genética , Biomarcadores Ambientais/genética , Genes Bacterianos/genética , Actinobacteria/metabolismo , Bacillus megaterium/metabolismo , Expressão Gênica , México , Mineração , Níquel/metabolismo , Microbiologia do Solo , Poluentes do Solo/metabolismo , Vanádio/metabolismo
6.
Environ Sci Pollut Res Int ; 27(5): 5584-5594, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31853852

RESUMO

Zero-valent iron (ZVI) has been widely applied to the remediation of uranium (U)-contaminated water. Notably, indigenous bacteria may possess potential positive or unfavorable influence on the mechanism and stability of Fe-U precipitates. However, the focus of the researches in this field has mainly been on physical and/or chemical aspects. In this study, batch experiments were conducted to explore the effects of an indigenous bacterium (Leifsonia sp.) on Fe-U precipitates and the corresponding removal efficiency by ZVI under different environmental factors. The results showed that the removal rate and capacity of U(VI) was significantly inhibited and decreased by ZVI when the pH increased to near-neutral level (pH = 6~8). However, in the ZVI + Leifsonia sp. coexistence system, the U(VI) removal efficiency were maintained at high levels (over 90%) within the experimental scope (pH = 3~8). This revealed that Leifsonia sp. had a synergistic effect on U(VI) remove by ZVI. According to scanning electron microscope and energy dispersive X-ray detector (SEM-EDX) analysis, dense scaly uranium-phosphate precipitation was observed on ZVI + Leifsonia sp. surface. The X-photoelectron spectroscopy (XPS) and Fourier transform infrared spectroscopy (FTIR) analysis indicated that Leifsonia sp. facilitated the generation of U(VI)-phosphates precipitates. The X-ray diffraction (XRD) analyses further revealed that new substances, such as (Fe(II)Fe(III)2(PO4)2(OH)2), Fe(II)(UO2)2(PO4)2·8H2O, Fe(II)Fe(III)5(PO4)4(OH)2·4H2O, etc., were produced in the coexisting system of ZVI and Leifsonia sp. This study provides new insights on the feasibility and validity of site application of ZVI to U(VI)-contaminated subsurface water in situ. Graphical abstract.


Assuntos
Actinobacteria/metabolismo , Urânio , Poluentes Químicos da Água , Biodegradação Ambiental , Ferro , Espectroscopia Fotoeletrônica , Difração de Raios X
7.
PLoS One ; 14(12): e0226959, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31887193

RESUMO

Literature surveys, taxonomical differences, and bioassay results have been utilized in the discovery of new natural products to aid in Actinomycetes isolate-selection. However, no or less investigation have been done on establishing the differences in metabolomic profiles of the isolated microorganisms. The study aims to utilise bioassay- and metabolomics-guided tools that included dereplication study and multivariate analysis of the NMR and mass spectral data of microbial extracts to assist the selection of isolates for scaling-up the production of antimicrobial natural products. A total of 58 actinomycetes were isolated from different soil samples collected from Ihnasia City, Egypt and screened for their antimicrobial activities against indicator strains that included Bacillus subtilis, Escherichia coli, methicillin-resistant Staphylococcus aureus and Candida albicans. A number of 25 isolates were found to be active against B. subtilis and/or to at least one of the tested indicator strains. Principal component analyses showed chemical uniqueness for four outlying bioactive actinomycetes extracts. In addition, Orthogonal Projections to Latent Structures Discriminant Analysis (OPLS-DA) and dereplication study led us to further select two outlying anti-MRSA active isolates MS.REE.13 and 22 for scale-up work. MS.REE.13 and 22 exhibited zones of inhibition at 19 and 13 mm against MRSA, respectively. A metabolomics-guided approach provided the steer to target the bioactive metabolites (P<0.01) present in a crude extract or fraction even at nanogram levels but it was a challenge that such low-yielding bioactive natural products would be feasible to isolate. Validated to occur only on the active side of OPLS-DA loadings plot, the isolated compounds exhibited medium to weak antibiotic activity with MIC values between 250 and 800 µM. Two new compounds, P_24306 (C10H13N2) and N_12799 (C18H32O3) with MICs of 795 and 432 µM, were afforded from the scale-up of MS.REE. 13 and 22, respectively.


Assuntos
Actinobacteria/isolamento & purificação , Anti-Infecciosos/isolamento & purificação , Microbiologia do Solo , Actinobacteria/química , Actinobacteria/metabolismo , Anti-Infecciosos/farmacologia , Bioensaio , Produtos Biológicos/isolamento & purificação , Produtos Biológicos/farmacologia , Egito , Concentração Inibidora 50 , Metabolômica , Testes de Sensibilidade Microbiana
8.
Curr Top Med Chem ; 19(31): 2868-2918, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31724505

RESUMO

Actinomycetes is an abundant resource for discovering a large number of lead compounds, which play an important role in microbial drug discovery. Compared to terrestrial microorganisms, marine actinomycetes have unique metabolic pathways because of their special living environment, which has the potential to produce a variety of bioactive substances. In this paper, secondary metabolites isolated from marine actinomycetes are reviewed (2013-2018), most of which exhibited cytotoxic, antibacterial, and antiviral biological activities.


Assuntos
Actinobacteria/química , Antibacterianos/metabolismo , Antineoplásicos/metabolismo , Antivirais/metabolismo , Produtos Biológicos/metabolismo , Actinobacteria/metabolismo , Antibacterianos/química , Antibacterianos/isolamento & purificação , Antineoplásicos/química , Antineoplásicos/isolamento & purificação , Antivirais/química , Antivirais/isolamento & purificação , Produtos Biológicos/química , Produtos Biológicos/isolamento & purificação , Humanos
9.
Pan Afr Med J ; 33: 329, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31692847

RESUMO

Introduction: This study was carried out to isolate and screen actinomycetes from soil of two salterns in Taza-Morocco, for the production of antimicrobial compounds against a set of target bacteria. Also, it aims to highlight some practices in order to isolates actinomycetes and screen for their ability to produce antibacterial compounds. Methods: Soil samples were analyzed for physical and chemical parameters including pH, electrical conductivity, and salinity. The actinomycetes were isolated on Casein Starch Agar (CSA) medium and purified on International Streptomyces Project 2 (ISP-2) medium. Antimicrobial activity of actinomycete isolates was evaluated by measuring the inhibition zone. These activities were tested against Dickeya solani IP2222, Pectobacterium brasiliensis 13471a, Escherichia coli K12, Proteus mirabilis, Pseudomonas aeruginosa CECT118, Listeria innocua CECT4030, Staphylococcus aureus CECT976, Bacillus subtilis DSM 347 and Candida alibicans, using three different culture media (CSA, Bennett and Mueller Hinton) and at two temperatures of incubation (30°C and 37°C). Results: Physical and chemical analysis of soil samples showed that both sites are alkaline. Also, with regards to salinity, the second site showed to contain high salt concentration compared the first site. The abundance of bacteria isolated on CSA medium from both sites showed correlation with the physical-chemical properties of the sampling soils. Incubation temperature of 30°C resulted in a high number of actinomycetes (18/22) isolates with antimicrobial effect relative to the temperature of 37°C (4/22). Some actinomycetes isolates show antimicrobial effect on only one culture medium, which shows a special nutritional requirement to express their antimicrobial effect. On the other hand, some isolates, they express their antimicrobial effect on the three media at the same time. Additionally, some isolates of actinomycetes inhibit the growth of several microorganisms at once. While others inhibit the growth of only one microorganism tested which reflects a possible specificity of antimicrobial substances. Conclusion: Growth conditions including, media composition, temperature of incubation and the spectrum of test strain tailors the behavior of the antimicrobial screening.


Assuntos
Actinobacteria/metabolismo , Anti-Infecciosos/farmacologia , Bactérias/efeitos dos fármacos , Microbiologia do Solo , Actinobacteria/isolamento & purificação , Anti-Infecciosos/isolamento & purificação , Candida albicans/efeitos dos fármacos , Meios de Cultura , Testes de Sensibilidade Microbiana , Marrocos , Temperatura
10.
Microbiology ; 165(11): 1169-1180, 2019 11.
Artigo em Inglês | MEDLINE | ID: mdl-31592756

RESUMO

Polar and subpolar ecosystems are highly vulnerable to global climate change with consequences for biodiversity and community composition. Bacteria are directly impacted by future environmental change and it is therefore essential to have a better understanding of microbial communities in fluctuating ecosystems. Exploration of Polar environments, specifically sediments, represents an exciting opportunity to uncover bacterial and chemical diversity and link this to ecosystem and evolutionary parameters. In terms of specialized metabolite production, the bacterial order Actinomycetales, within the phylum Actinobacteria are unsurpassed, producing 10 000 specialized metabolites accounting for over 45 % of all bioactive microbial metabolites. A selective isolation approach focused on spore-forming Actinobacteria of 12 sediment cores from the Antarctic and sub-Arctic generated a culture collection of 50 strains. This consisted of 39 strains belonging to rare A ctinomycetales genera including Microbacterium, Rhodococcus and Pseudonocardia. This study used a combination of nanopore sequencing and molecular networking to explore the community composition, culturable bacterial diversity, evolutionary relatedness and specialized metabolite potential of these strains. Metagenomic analyses using MinION sequencing was able to detect the phylum Actinobacteria across polar sediment cores at an average of 13 % of the total bacterial reads. The resulting molecular network consisted of 1652 parent ions and the lack of known metabolite identification supports the argument that Polar bacteria are likely to produce previously unreported chemistry.


Assuntos
Actinobacteria/genética , Actinobacteria/metabolismo , Actinobacteria/classificação , Actinobacteria/isolamento & purificação , Regiões Antárticas , Regiões Árticas , Biodiversidade , Produtos Biológicos/classificação , Produtos Biológicos/metabolismo , DNA Bacteriano/genética , Evolução Molecular , Sedimentos Geológicos/microbiologia , Metagenômica , Microbiota/genética , Filogenia , RNA Ribossômico 16S/química
11.
Environ Sci Pollut Res Int ; 26(32): 33683-33693, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31595408

RESUMO

Cellulose and lignin belongs to refractory organic matters in the traditional composting. In this research, the degradation of lignocellulose in dairy cattle manure was investigated through adding calcium oxide (CaO) and superphosphate (SSP). In the presence of CaO and SSP, the degradation rate of cellulose and lignin were improved by 25.0% and 8.33%, respectively. The results indicated that the pH value in system would be slightly higher with the addition of CaO and SSP. Besides, the pH value of all cow manure piles were about 8.4 after composting rotten, which could be well neutralized by the gradually acidified soil in the southwest of China with the full effect of fertilizer released. In addition, the abundance of Bacillales, Actinomycetes, and Thermoactinomycetaceae in the experimental groups (AR) was slightly better than that in the control groups (CK) during composting, which led to a conclusion that an elaborate physical-chemical-multivariate aerobic microorganism evolution model of cellulose degradation products (PCMC) was deduced and the physical-chemical-multivariate aerobic microorganism model of lignin cycle degradation (PCML) was developed.


Assuntos
Compostos de Cálcio/química , Compostagem/métodos , Difosfatos/química , Lignina , Esterco/análise , Óxidos/química , Actinobacteria/metabolismo , Animais , Bovinos , Celulose , China , Feminino , Fertilizantes , Concentração de Íons de Hidrogênio , Lignina/metabolismo , Solo
12.
Cell Host Microbe ; 26(4): 463-477.e8, 2019 10 09.
Artigo em Inglês | MEDLINE | ID: mdl-31585844

RESUMO

Dramatic increases in processed food consumption represent a global health threat. Maillard reaction products (MRPs), which are common in processed foods, form upon heat-induced reaction of amino acids with reducing sugars and include advanced glycation end products with deleterious health effects. To examine how processed foods affect the microbiota, we fed gnotobiotic mice, colonized with 54 phylogenetically diverse human gut bacterial strains, defined sugar-rich diets containing whey as the protein source or a matched amino acid mixture. Whey or ϵ-fructoselysine, an MRP in whey and many processed foods, selectively increases Collinsella intestinalis absolute abundance and induces Collinsella expression of genomic loci directing import and metabolism of ϵ-fructoselysine to innocuous products. This locus is repressed by glucose in C. aerofaciens, whose abundance decreases with whey, but is not repressed in C. intestinalis. Identifying gut organisms responding to and degrading potentially harmful processed food components has implications for food science, microbiome science, and public health.


Assuntos
Actinobacteria/metabolismo , Fast Foods/análise , Inocuidade dos Alimentos , Produtos Finais de Glicação Avançada/metabolismo , Lisina/análogos & derivados , Actinobacteria/genética , Animais , Qualidade dos Alimentos , Microbioma Gastrointestinal , Vida Livre de Germes , Humanos , Lisina/metabolismo , Reação de Maillard , Camundongos , Camundongos Endogâmicos C57BL , Proteínas do Soro do Leite/metabolismo
13.
Nat Biotechnol ; 37(11): 1314-1321, 2019 11.
Artigo em Inglês | MEDLINE | ID: mdl-31570900

RESUMO

Most microorganisms from all taxonomic levels are uncultured. Single-cell genomes and metagenomes continue to increase the known diversity of Bacteria and Archaea; however, while 'omics can be used to infer physiological or ecological roles for species in a community, most of these hypothetical roles remain unvalidated. Here, we report an approach to capture specific microorganisms from complex communities into pure cultures using genome-informed antibody engineering. We apply our reverse genomics approach to isolate and sequence single cells and to cultivate three different species-level lineages of human oral Saccharibacteria (TM7). Using our pure cultures, we show that all three Saccharibacteria species are epibionts of diverse Actinobacteria. We also isolate and cultivate human oral SR1 bacteria, which are members of a lineage of previously uncultured bacteria. Reverse-genomics-enabled cultivation of microorganisms can be applied to any species from any environment and has the potential to unlock the isolation, cultivation and characterization of species from as-yet-uncultured branches of the microbial tree of life.


Assuntos
Actinobacteria/metabolismo , Anticorpos/metabolismo , Proteínas de Membrana/imunologia , Boca/microbiologia , Análise de Célula Única/métodos , Actinobacteria/classificação , Actinobacteria/genética , Actinobacteria/isolamento & purificação , Proteínas de Bactérias/química , Proteínas de Bactérias/genética , Proteínas de Bactérias/imunologia , Genômica , Humanos , Proteínas de Membrana/química , Proteínas de Membrana/genética , Modelos Moleculares , Filogenia , Conformação Proteica , Genética Reversa , Análise de Sequência de DNA
14.
Bull Environ Contam Toxicol ; 103(6): 808-813, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31602500

RESUMO

Certain microbes can biotransform antibiotics. Little is known about these microbes or the biotransformation processes. The objective of this study was to determine the effects of background nutrient conditions on a sulfonamide degrading culture and on its biotransformation of sulfadiazine (SDZ) with respect to transformation kinetics and transformation products. The mixed culture capable of degrading SDZ consisted primarily of three genera, Brevibacterium, Castellaniella and Leucobacter. The maximum biotransformation rate was 4.55 mg L-1 d-1 in the absence of background nutrients. Among the three background nutrient conditions tested, diluted R2A medium lead to the highest maximum SDZ biotransformation rates, followed by humic acid and glucose. 2-aminopyrimidine was the major SDZ biotransformation product under the background nutrient conditions tested, while another previously reported biotransformation product, sulfanilic acid, was further degraded by the mixed culture. The findings from this study can help improve our estimation of the fate of antibiotics in the environment.


Assuntos
Antibacterianos/metabolismo , Meios de Cultura/química , Microbiologia do Solo , Poluentes do Solo/metabolismo , Sulfadiazina/metabolismo , Actinobacteria/metabolismo , Alcaligenaceae/metabolismo , Biodegradação Ambiental , Biotransformação , Brevibacterium/metabolismo , Glucose/química , Substâncias Húmicas/análise , Cinética , Pirimidinas/química
15.
Curr Microbiol ; 76(12): 1461-1466, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31552451

RESUMO

Imidacloprid (C9H10ClN5O2) is used as the most recommended type of insecticide in vegetable farming worldwide. Two types of bacteria (Methylobacterium radiotolerans and Microbacterium arthrosphaerae) were isolated from a corn farming field in the Thrace region of Turkey, and then consortia of these bacteria were prepared from equal volumes of 107 CFU/ml for each bacterium type. Imidacloprid remediation studies were carried out during 18 days in soil test units. The water filtered from these soil test units was determined for chemical oxygen demand (COD) and biochemical oxygen demand (BOD5) to determine the optimum concentration of microorganisms to ascertain the best removal efficiency of Imidacloprid. COD removal rates were 98.7%, 96.4% and 51.6% with 80, 40, and 20 ml volumes of the consortia of bacteria, respectively, at the end of 18 days. The BOD5 removal rates were 88.4%, 78.6% and 49.9% in the same volumes of bacteria, respectively. As a result of this study, we have found that this bacterial consortium is very effective for the bioremediation of this insecticide at the two volumes of 40 and 80 ml, both being better than 20 ml.


Assuntos
Actinobacteria/metabolismo , Biodegradação Ambiental , Inseticidas/metabolismo , Methylobacterium/metabolismo , Neonicotinoides/metabolismo , Nitrocompostos/metabolismo , Poluentes do Solo/metabolismo , Análise da Demanda Biológica de Oxigênio , Consórcios Microbianos , Microbiologia do Solo
16.
J Mass Spectrom ; 54(10): 823-833, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31476245

RESUMO

Actinobacteria are one of the most promising producers of medically and industrially relevant secondary metabolites. However, screening of such compounds in actinobacteria growth demands simple, fast, and efficient extraction procedures that enable detection and precise quantification of biologically active compounds. In this regard, solid phase microextraction (SPME) emerges as an ideal extraction technique for screening of secondary metabolites in bacteria culture due to its non-exhaustive, minimally invasive, and non-destructive nature: its integrated sample preparation workflow; balanced coverage feature; metabolism quenching capabilities; and superior cleanup, as well as its versatility in configuration, which enables automation and high throughput applications. The current work provides a comparison of micro-scale and direct immersion SPME (DI-SPME) for screening of secondary metabolites, describes the optimization of the developed DI-SPME method, and introduces the developed technique for mapping of target secondary metabolites as well as its direct coupling to mass spectrometry for such applications. The optimized DI-SPME method provided higher amounts of extracted ions and intensity signals, yielding superior extraction and desorption efficiency as compared with micro-scale extraction. Studied compounds presented stability on the coating for 24 h at room temperature. The DI-SPME mapping approach revealed that lysolipin I and the lienomycin analog are distributed along the center and edges of the colony, respectively. Direct coupling of SPME to MS provided a similar ions profile as SPME-LC-MS while enabling a significant decrease in analysis time, demonstrating its suitability for such applications. DI-SPME is herein presented as an alternative to micro-scale extraction for screening of secondary metabolites in actinobacteria solid medium, as well as a feasible alternative to DESI-IMS for mapping of biologic radial distribution of secondary metabolites and cell life cycle studies. Lastly, the direct coupling of DI-SPME to MS is presented as a fast, powerful technique for high throughput analysis of secondary metabolites in this medium.


Assuntos
Actinobacteria/metabolismo , Metabolômica , Metabolismo Secundário , Microextração em Fase Sólida , Cromatografia Líquida de Alta Pressão , Ensaios de Triagem em Larga Escala , Polienos/análise , Análise de Componente Principal , Espectrometria de Massas em Tandem , Xantenos/análise
17.
Int J Mol Sci ; 20(16)2019 Aug 11.
Artigo em Inglês | MEDLINE | ID: mdl-31405215

RESUMO

In family GH13 of the carbohydrate-active enzyme database, subfamily 18 contains glycoside phosphorylases that act on α-sugars and glucosides. Because their phosphorolysis reactions are effectively reversible, these enzymes are of interest for the biocatalytic synthesis of various glycosidic compounds. Sucrose 6F-phosphate phosphorylases (SPPs) constitute one of the known substrate specificities. Here, we report the characterization of an SPP from Ilumatobacter coccineus with a far stricter specificity than the previously described promiscuous SPP from Thermoanaerobacterium thermosaccharolyticum. Crystal structures of both SPPs were determined to provide insight into their similarities and differences. The residues responsible for binding the fructose 6-phosphate group in subsite +1 were found to differ considerably between the two enzymes. Furthermore, several variants that introduce a higher degree of substrate promiscuity in the strict SPP from I. coccineus were designed. These results contribute to an expanded structural knowledge of enzymes in subfamily GH13_18 and facilitate their rational engineering.


Assuntos
Actinobacteria/enzimologia , Fosforilases/metabolismo , Sacarose/metabolismo , Thermoanaerobacterium/enzimologia , Actinobacteria/química , Actinobacteria/metabolismo , Cristalografia por Raios X , Modelos Moleculares , Fosforilases/química , Conformação Proteica , Especificidade por Substrato , Thermoanaerobacterium/química , Thermoanaerobacterium/metabolismo
18.
Nat Microbiol ; 4(11): 1862-1871, 2019 11.
Artigo em Inglês | MEDLINE | ID: mdl-31406334

RESUMO

Glycopeptide antibiotics are produced by Actinobacteria through biosynthetic gene clusters that include genes supporting their regulation, synthesis, export and resistance. The chemical and biosynthetic diversities of glycopeptides are the product of an intricate evolutionary history. Extracting this history from genome sequences is difficult as conservation of the individual components of these gene clusters is variable and each component can have a different trajectory. We show that glycopeptide biosynthesis and resistance in Actinobacteria maps to approximately 150-400 million years ago. Phylogenetic reconciliation reveals that the precursors of glycopeptide biosynthesis are far older than other components, implying that these clusters arose from a pre-existing pool of genes. We find that resistance appeared contemporaneously with biosynthetic genes, raising the possibility that the mechanism of action of glycopeptides was a driver of diversification in these gene clusters. Our results put antibiotic biosynthesis and resistance into an evolutionary context and can guide the future discovery of compounds possessing new mechanisms of action, which are especially needed as the usefulness of the antibiotics available at present is imperilled by human activity.


Assuntos
Actinobacteria/classificação , Vias Biossintéticas , Farmacorresistência Bacteriana , Actinobacteria/genética , Actinobacteria/metabolismo , Antibacterianos/biossíntese , Antibacterianos/química , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Evolução Molecular , Glicopeptídeos/biossíntese , Glicopeptídeos/química , Família Multigênica , Filogenia
19.
Lett Appl Microbiol ; 69(4): 294-301, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31424588

RESUMO

Saccharothrix algeriensis NRRL B-24137 is an actinobacterium isolated from Algerian Saharan soil. It produces bioactive compounds belonging to the dithiolopyrrolone class of antibiotics, which are characterized by the possession of a unique pyrrolinonodithiole nucleus. Dithiolopyrrolones are known for their strong antibacterial and antifungal activities. This class of antibiotics generated great interest after the discovery of their anticancer properties. In this study, an antibiotic named PR11, produced after a long bacterial fermentation (11 days) in sorbic acid-containing culture broth, was characterized as a new dithiolopyrrolone derivative. After HPLC analysis and purification, the chemical structure of this antibiotic was determined by 1 H- and 13 C-nuclear magnetic resonance, mass and UV-visible data. PR11 was thus characterized as an iso-hexanoyl-pyrrothine, a novel dithiolopyrrolone derivative. The minimum inhibitory concentrations of the new induced antibiotic were determined against several pathogenic micro-organisms. A moderate to strong activity was noted against all Gram-positive bacteria, filamentous fungi and yeasts tested. SIGNIFICANCE AND IMPACT OF THE STUDY: Given the strong activities of dithiolopyrrolones against diverse prokaryotic and eukaryotic micro-organisms including potent selective-anticancer activity, the discovery of new-related derivatives draw continuous attention for therapeutic research. Depending on nature and concentration of added precursor, Saccharothrix algeriensis NRRL B-24137 produce several dithiolopyrrolone coumpounds. In this study, sorbic acid addition combined to long fermentation duration was shown to induce the biosynthesis of a novel dithiolopyrrolone derivative. After purification and full spectroscopic and spectrometric study, the compound was characterized as iso-hexanoyl-pyrrothine. In the future investigation for novel dithiolopyrrolone discovery, fermentation duration should be regarded as a key parameter as well.


Assuntos
Actinobacteria/metabolismo , Anti-Infecciosos/farmacologia , Fungos/efeitos dos fármacos , Bactérias Gram-Positivas/efeitos dos fármacos , Pirróis/farmacologia , Fermentação , Testes de Sensibilidade Microbiana , Ácido Sórbico/metabolismo
20.
Ecotoxicol Environ Saf ; 183: 109573, 2019 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-31442809

RESUMO

Aluminum (Al) bioaccumulation by a novel Al and drought tolerant Curtobacterium herbarum strain CAH5 isolated from rhizosphere soil of Beta vulgaris grown in acidic Andisols were examined. The rhizobacterial strain also presented important plant growth promoting traits even with Al and drought stresses under in-vitro conditions in broth. In experiments with a 2-6 mM as initial Al concentrations, the percentages of Al removal by bacteria were 89-93% and 78-91% within 72 h incubation under the normal and drought conditions, respectively. Cytogenotoxicity assay revealed that the toxicity of Al was reduced after bioaccumulation process. In the greenhouse study, formulated bio-inoculant CAH5 significantly improves the Lactuca sativa growth under Al and drought stress by reducing oxidative stress, lipid peroxidation and Al accumulation in plant parts. Our results highlighted that strain CAH5 could be used as a promising bioresource for restoration of agricultural soil with presence of phytotoxic Al improving crop production even under drought conditions.


Assuntos
Actinobacteria/fisiologia , Alumínio/metabolismo , Secas , Alface/crescimento & desenvolvimento , Reguladores de Crescimento de Planta/fisiologia , Actinobacteria/metabolismo , Alumínio/toxicidade , Biodegradação Ambiental , Caryophyllales/crescimento & desenvolvimento , Caryophyllales/microbiologia , Alface/efeitos dos fármacos , Alface/microbiologia , Reguladores de Crescimento de Planta/metabolismo , Rizosfera , Microbiologia do Solo , Estresse Fisiológico/efeitos dos fármacos
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