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1.
Nucleic Acids Res ; 48(3): 1583-1598, 2020 02 20.
Artigo em Inglês | MEDLINE | ID: mdl-31956908

RESUMO

Cyclic dimeric 3'-5' guanosine monophosphate, c-di-GMP, is a ubiquitous second messenger controlling diverse cellular processes in bacteria. In streptomycetes, c-di-GMP plays a crucial role in a complex morphological differentiation by modulating an activity of the pleiotropic regulator BldD. Here we report that c-di-GMP plays a key role in regulating secondary metabolite production in streptomycetes by altering the expression levels of bldD. Deletion of cdgB encoding a diguanylate cyclase in Streptomycesghanaensis reduced c-di-GMP levels and the production of the peptidoglycan glycosyltransferase inhibitor moenomycin A. In contrast to the cdgB mutant, inactivation of rmdB, encoding a phosphodiesterase for the c-di-GMP hydrolysis, positively correlated with the c-di-GMP and moenomycin A accumulation. Deletion of bldD adversely affected the synthesis of secondary metabolites in S. ghanaensis, including the production of moenomycin A. The bldD-deficient phenotype is partly mediated by an increase in expression of the pleiotropic regulatory gene wblA. Genetic and biochemical analyses demonstrate that a complex of c-di-GMP and BldD effectively represses transcription of wblA, thus preventing sporogenesis and sustaining antibiotic synthesis. These results show that manipulation of the expression of genes controlling c-di-GMP pool has the potential to improve antibiotic production as well as activate the expression of silent gene clusters.


Assuntos
Proteínas de Bactérias/genética , Bambermicinas/biossíntese , Produtos Biológicos/metabolismo , GMP Cíclico/análogos & derivados , Proteínas de Ligação a DNA/genética , Fatores de Transcrição/genética , Proteínas de Bactérias/antagonistas & inibidores , GMP Cíclico/genética , GMP Cíclico/metabolismo , Proteínas de Ligação a DNA/antagonistas & inibidores , Proteínas de Escherichia coli/genética , Deleção de Genes , Regulação Bacteriana da Expressão Gênica/genética , Nucleotídeos/genética , Peptidoglicano Glicosiltransferase/antagonistas & inibidores , Fósforo-Oxigênio Liases/genética , Sistemas do Segundo Mensageiro/genética , Streptomycetaceae/genética , Streptomycetaceae/metabolismo , Fatores de Transcrição/antagonistas & inibidores
2.
Proc Natl Acad Sci U S A ; 116(28): 13964-13969, 2019 07 09.
Artigo em Inglês | MEDLINE | ID: mdl-31243147

RESUMO

Carboxylases are biocatalysts that capture and convert carbon dioxide (CO2) under mild conditions and atmospheric concentrations at a scale of more than 400 Gt annually. However, how these enzymes bind and control the gaseous CO2 molecule during catalysis is only poorly understood. One of the most efficient classes of carboxylating enzymes are enoyl-CoA carboxylases/reductases (Ecrs), which outcompete the plant enzyme RuBisCO in catalytic efficiency and fidelity by more than an order of magnitude. Here we investigated the interactions of CO2 within the active site of Ecr from Kitasatospora setae Combining experimental biochemistry, protein crystallography, and advanced computer simulations we show that 4 amino acids, N81, F170, E171, and H365, are required to create a highly efficient CO2-fixing enzyme. Together, these 4 residues anchor and position the CO2 molecule for the attack by a reactive enolate created during the catalytic cycle. Notably, a highly ordered water molecule plays an important role in an active site that is otherwise carefully shielded from water, which is detrimental to CO2 fixation. Altogether, our study reveals unprecedented molecular details of selective CO2 binding and C-C-bond formation during the catalytic cycle of nature's most efficient CO2-fixing enzyme. This knowledge provides the basis for the future development of catalytic frameworks for the capture and conversion of CO2 in biology and chemistry.


Assuntos
Aminoácidos/química , Dióxido de Carbono/química , Ácidos Graxos Dessaturases/química , Modelos Moleculares , Aminoácidos/genética , Aminoácidos/metabolismo , Dióxido de Carbono/metabolismo , Proteínas de Transporte/química , Catálise , Domínio Catalítico/genética , Enzimas/química , Ácidos Graxos Dessaturases/metabolismo , Streptomycetaceae/química , Streptomycetaceae/enzimologia
3.
Mar Drugs ; 17(3)2019 Mar 21.
Artigo em Inglês | MEDLINE | ID: mdl-30901830

RESUMO

Two new piperazine-triones lansai E and F (1, 2), together with four known secondary metabolites lansai D (3), 1-N-methyl-(E,Z)-albonoursin (4), imidazo[4,5-e]-1,2,4-triazine (5), and streptonigrin (6) were isolated from a deep-sea-derived Streptomycetes sp. strain SMS636. The structures of the isolated compounds were confirmed by comprehensive spectroscopic analysis, including HRESIMS, 1D and 2D NMR. Compound 4 exhibited moderate antibacterial activities against Staphylococcus aureus and methicillin resistant S. aureus (MRSA) with Minimum Inhibitory Concentration (MIC) values of 12.5 and 25 µg/mL, respectively. Compound 6 displayed significant antibacterial activities against S. aureus, MRSA and Bacillus Calmette-Guérin (BCG) with MIC values of 0.78, 0.78 and 1.25 µg/mL, respectively.


Assuntos
Antibacterianos/química , Antibacterianos/farmacologia , Piperazina/análogos & derivados , Streptomycetaceae/química , Antibacterianos/isolamento & purificação , Candida albicans/efeitos dos fármacos , Escherichia coli/efeitos dos fármacos , Staphylococcus aureus Resistente à Meticilina/efeitos dos fármacos , Testes de Sensibilidade Microbiana , Piperazina/química , Piperazina/isolamento & purificação , Piperazina/farmacologia , Pseudomonas aeruginosa/efeitos dos fármacos , Staphylococcus aureus/efeitos dos fármacos
4.
Molecules ; 24(5)2019 Mar 03.
Artigo em Inglês | MEDLINE | ID: mdl-30832456

RESUMO

The emergence and spread of antibiotic-resistant pathogens is a major public health issue, which requires global action of an intersectoral nature. Multidrug-resistant (MDR) pathogens-especially "ESKAPE" bacteria-can withstand lethal doses of antibiotics with various chemical structures and mechanisms of action. Pharmaceutical companies are increasingly turning away from participating in the development of new antibiotics, due to the regulatory environment and the financial risks. There is an urgent need for innovation in antibiotic research, as classical discovery platforms (e.g., mining soil Streptomycetes) are no longer viable options. In addition to discovery platforms, a concept of an ideal antibiotic should be postulated, to act as a blueprint for future drugs, and to aid researchers, pharmaceutical companies, and relevant stakeholders in selecting lead compounds. Based on 150 references, the aim of this review is to summarize current advances regarding the challenges of antibiotic drug discovery and the specific attributes of an ideal antibacterial drug (a prodrug or generally reactive compound with no specific target, broad-spectrum antibacterial activity, adequate penetration through the Gram-negative cell wall, activity in biofilms and in hard-to-treat infections, accumulation in macrophages, availability for oral administration, and for use in sensitive patient groups).


Assuntos
Antibacterianos/uso terapêutico , Biofilmes/efeitos dos fármacos , Desenho de Fármacos , Descoberta de Drogas/tendências , Antibacterianos/efeitos adversos , Biofilmes/crescimento & desenvolvimento , Farmacorresistência Bacteriana Múltipla , Humanos , Streptomycetaceae/efeitos dos fármacos , Streptomycetaceae/patogenicidade
5.
Int J Syst Evol Microbiol ; 69(4): 1047-1056, 2019 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-30741626

RESUMO

The taxonomic position of strain 15-057AT, an acidophilic actinobacterium isolated from the bronchial lavage of an 80-year-old male, was determined using a polyphasic approach incorporating morphological, phenotypic, chemotaxonomic and genomic analyses. Pairwise 16S rRNA gene sequence similarities calculated using the GGDC web server between strain 15-057AT and its closest phylogenetic neighbours, Streptomyces griseoplanus NBRC 12779T and Streptacidiphilus oryzae TH49T, were 99.7 and 97.6 %, respectively. The G+C content of isolate 15-057AT was determined to be 72.6 mol%. DNA-DNA relatedness and average nucleotide identity between isolate 15-057AT and Streptomyces griseoplanus DSM 40009T were 29.2±2.5 % and 85.97 %, respectively. Chemotaxonomic features of isolate 15-057AT were consistent with its assignment within the genus Streptacidiphilus: the whole-cell hydrolysate contained ll-diaminopimelic acid as the diagnostic diamino acid and glucose, mannose and ribose as cell-wall sugars; the major menaquinone was MK9(H8); the polar lipid profile consisted of diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylinositol, glycophospholipid, aminoglycophospholipid and an unknown lipid; the major fatty acids were anteiso-C15 : 0 and iso-C16 : 0. Phenotypic and morphological traits distinguished isolate 15-057AT from its closest phylogenetic neighbours. The results of our taxonomic analyses showed that strain 15-057AT represents a novel species within the evolutionary radiation of the genus Streptacidiphilus, for which the name Streptacidiphilus bronchialis sp. nov. is proposed. The type strain is 15-057AT (=DSM 106435T=ATCC BAA-2934T).


Assuntos
Líquido da Lavagem Broncoalveolar/microbiologia , Filogenia , Streptomyces/classificação , Streptomycetaceae/classificação , Idoso de 80 Anos ou mais , Técnicas de Tipagem Bacteriana , Composição de Bases , Ciprofloxacino , DNA Bacteriano/genética , Ácido Diaminopimélico/química , Farmacorresistência Bacteriana , Ácidos Graxos/química , Humanos , Masculino , Fosfolipídeos/química , RNA Ribossômico 16S/genética , Análise de Sequência de DNA , Streptomycetaceae/isolamento & purificação , Tennessee
6.
Nat Chem Biol ; 15(2): 111-114, 2019 02.
Artigo em Inglês | MEDLINE | ID: mdl-30598544

RESUMO

Here we report a transcription factor decoy strategy for targeted activation of eight large silent polyketide synthase and non-ribosomal peptide synthetase gene clusters, ranging from 50 to 134 kilobases (kb) in multiple streptomycetes, and characterization of a novel oxazole family compound produced by a 98-kb biosynthetic gene cluster. Owing to its simplicity and ease of use, this strategy can be scaled up readily for discovery of natural products in streptomycetes.


Assuntos
Peptídeo Sintases/genética , Policetídeo Sintases/genética , Fatores de Transcrição/biossíntese , Regulação da Expressão Gênica/genética , Família Multigênica/fisiologia , Peptídeo Sintases/fisiologia , Policetídeo Sintases/fisiologia , Streptomycetaceae/metabolismo
7.
J Agric Food Chem ; 67(5): 1453-1462, 2019 Feb 06.
Artigo em Inglês | MEDLINE | ID: mdl-30638374

RESUMO

ε-Poly-l-lysine (ε-PL) is a natural antimicrobial cationic peptide, which is generally recognized as safe for use as a food preservative. To date, the production capacity of strains that produce low-molecular weight ε-PL remains very low and thus unsuitable for industrial production. Here, we report a new low-molecular weight ε-PL-producing Kitasatospora aureofaciens strain. The ε-PL synthase gene of this strain was cloned into a high ε-PL-producing Streptomyces albulus strain. The resulting recombinant strain efficiently produced ε-PL with a molecular weight of 1.3-2.3 kDa and yielded of 23.6 g/L following fed-batch fermentation in a 5 L bioreactor. In addition, circular dichroism spectra showed that this ε-PL takes on a conformation similar to an antiparallel pleated-sheet. Moreover, it demonstrated better antimicrobial activity against yeast compared to the 3.2-4.5 kDa ε-PL. This study provides a highly efficient strategy for production of the low-molecular weight ε-PL, which helps to expand its potential applications.


Assuntos
Proteínas de Bactérias/genética , Ligases/genética , Polilisina/biossíntese , Streptomyces/metabolismo , Streptomycetaceae/enzimologia , Antifúngicos/química , Antifúngicos/metabolismo , Antifúngicos/farmacologia , Proteínas de Bactérias/metabolismo , Clonagem Molecular , Fermentação , Ligases/metabolismo , Polilisina/química , Polilisina/farmacologia , Streptomyces/genética , Streptomycetaceae/genética , Leveduras/efeitos dos fármacos
8.
Bioresour Technol ; 272: 315-325, 2019 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-30384206

RESUMO

A novel strategy for the low-cost, high-yield co-production of xylose and xylooligosaccharides together with no xylose inhibition was developed using a novel heterologous expression of XYN10Ks_480 endo-1,4-ß-xylanase with a ricin-type ß-trefoil type of domain and XYN11Ks_480 endo-1,4-ß-xylanase with a CBM 2 superfamily from the Kitasatospora sp in an actinomycetes expression system. Xylose is the main building block for hemicellulose xylan. Our findings demonstrated high levels of expression and catalytic activity for XYN10Ks_480 during hydrolysis of the extracted xylan of bagasse, and three types of xylan-based substrates were used to produce xylose and xylooligosaccharides. However, hydrolysis by XYN11Ks_480 produced xylooligosaccharides without xylose formation. This study demonstrated how integrating sodium hypochlorite-extracted xylan and enzymatic hydrolysis could provide an alternative strategy for the generation of XOS from lignocellulosic material.


Assuntos
Celulose/metabolismo , Endo-1,4-beta-Xilanases/metabolismo , Glucuronatos/metabolismo , Oligossacarídeos/metabolismo , Polissacarídeos/metabolismo , Saccharum/metabolismo , Streptomycetaceae/enzimologia , Xilose/biossíntese , Hidrólise
9.
BMC Genomics ; 19(1): 724, 2018 Oct 03.
Artigo em Inglês | MEDLINE | ID: mdl-30285620

RESUMO

BACKGROUND: The question of whether bacterial species objectively exist has long divided microbiologists. A major source of contention stems from the fact that bacteria regularly engage in horizontal gene transfer (HGT), making it difficult to ascertain relatedness and draw boundaries between taxa. A natural way to define taxa is based on exclusivity of relatedness, which applies when members of a taxon are more closely related to each other than they are to any outsider. It is largely unknown whether exclusive bacterial taxa exist when averaging over the genome or are rare due to rampant hybridization. RESULTS: Here, we analyze a collection of 701 genomes representing a wide variety of environmental isolates from the family Streptomycetaceae, whose members are competent at HGT. We find that the presence/absence of auxiliary genes in the pan-genome displays a hierarchical (tree-like) structure that correlates significantly with the genealogy of the core-genome. Moreover, we identified the existence of many exclusive taxa, although individual genes often contradict these taxa. These conclusions were supported by repeating the analysis on 1,586 genomes belonging to the genus Bacillus. However, despite confirming the existence of exclusive groups (taxa), we were unable to identify an objective threshold at which to assign the rank of species. CONCLUSIONS: The existence of bacterial taxa is justified by considering average relatedness across the entire genome, as captured by exclusivity, but is rejected if one requires unanimous agreement of all parts of the genome. We propose using exclusivity to delimit taxa and conventional genome similarity thresholds to assign bacterial taxa to the species rank. This approach recognizes species that are phylogenetically meaningful, while also establishing some degree of comparability across species-ranked taxa in different bacterial clades.


Assuntos
Fluxo Gênico , Streptomycetaceae/classificação , Streptomycetaceae/genética , Transferência Genética Horizontal , Genes Bacterianos/genética , Filogenia
10.
Mol Biol Rep ; 45(6): 2563-2570, 2018 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-30311126

RESUMO

The search for new compounds effective against Mycobacterium tuberculosis is still a priority in medicine. The evaluation of microorganisms isolated from non-conventional locations offers an alternative to look for new compounds with antimicrobial activity. Endophytes have been successfully explored as source of bioactive compounds. In the present work we studied the nature and antimycobacterial activity of a compound produced by Streptomyces scabrisporus, an endophyte isolated from the medicinal plant Amphipterygium adstringens. The active compound was detected as the main secondary metabolite present in organic extracts of the streptomycete and identified by NMR spectroscopic data as steffimycin B (StefB). This anthracycline displayed a good activity against M. tuberculosis H37Rv ATCC 27294 strain, with MIC100 and SI values of 7.8 µg/mL and 6.42, respectively. When tested against the rifampin mono resistant M. tuberculosis Mtb-209 pathogen strain, a better activity was observed (MIC100 of 3.9 µg/mL), suggesting a different action mechanism of StefB from that of rifampin. Our results supported the endophyte Streptomyces scabrisporus as a good source of StefB for tuberculosis treatment, as this anthracycline displayed a strong bactericidal effect against M. tuberculosis, one of the oldest and more dangerous human pathogens causing human mortality.


Assuntos
Antraciclinas/farmacologia , Sapindaceae/metabolismo , Anacardiaceae , Antraciclinas/isolamento & purificação , Antraciclinas/metabolismo , Anti-Infecciosos/farmacologia , Antituberculosos , Endófitos/isolamento & purificação , Testes de Sensibilidade Microbiana , Mycobacterium tuberculosis/efeitos dos fármacos , Extratos Vegetais/isolamento & purificação , Plantas Medicinais/metabolismo , Sapindaceae/toxicidade , Streptomycetaceae/metabolismo
11.
Curr Biol ; 28(20): R1179-R1180, 2018 10 22.
Artigo em Inglês | MEDLINE | ID: mdl-30352181

RESUMO

What do you do when your food is too big to chew, or worse, when you don't have a stomach at all? Richards and Talbot explain how osmotrophs get around the problem by digesting on the outside.


Assuntos
Fungos/fisiologia , Oomicetos/fisiologia , Streptomycetaceae/fisiologia , Ingestão de Alimentos , Comportamento Alimentar , Interações Microbianas/fisiologia
12.
Int J Syst Evol Microbiol ; 68(9): 3149-3155, 2018 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-30102143

RESUMO

A moderately acidophilic actinobacterial strain, designated MMS16-CNU450T, was isolated from pine grove soil, and its taxonomic position was analysed using a polyphasic approach. The isolate showed best growth at 30 °C, pH 6 and 0.5 % (w/v) NaCl. On the basis of 16S rRNA gene sequence similarity, the isolate was assigned to the genus Streptacidiphilus, and the closest species were Streptacidiphilus rugosus AM-16T (sequence similarity, 98.61 %), Streptacidiphilus melanogenes NBRC 103184T (98.53 %), Streptacidiphilus jiangxiensis NBRC 100920T (98.19 %) and Streptacidiphilus anmyonensis NBRC 103185T (98.05 %). The isolate formed a distinct cluster of its own within the Streptacidiphilusclade in the phylogenetic tree. Based on whole-genome comparison between the strain MMS16-CNU450T and the type strains of related species, the orthologous average nucleotide identity and in silico DNA-DNA hybridization values were in the range of 77.9-87.0 and 22.3-32.7 %, respectively. The DNA G+C content of the isolate was 68.6 mol%. The phylogenetic, phenotypic, chemotaxonomic and genomic data supported the affiliation of the strain to Streptacidiphilus, and the name Streptacidiphilus pinicola sp. nov. (type strain, MMS16-CNU450T=KCTC 49008T=JCM 32300T) is proposed accordingly.


Assuntos
Florestas , Filogenia , Pinus/microbiologia , Microbiologia do Solo , Streptomycetaceae/classificação , Técnicas de Tipagem Bacteriana , Composição de Bases , DNA Bacteriano/genética , Ácidos Graxos/química , Hibridização de Ácido Nucleico , RNA Ribossômico 16S/genética , República da Coreia , Análise de Sequência de DNA , Streptomycetaceae/genética , Streptomycetaceae/isolamento & purificação
13.
J Microbiol ; 56(8): 571-578, 2018 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-30047086

RESUMO

Bafilomycins produced by Kitasatospora cheerisanensis KCTC- 2395 belong to the 16-membered macrolactone family plecomacrolide antibiotics. Bafilomycin B1 contains 2-amino- 3-hydroxycyclopent-2-enone (C5N), a five membered ring, which gets condensed via an amide linkage to bafilomycin polyketide. To study the biosynthetic pathway of C5N during bafilomycin biosynthesis in K. cheerisanensis KCTC2395, we attempted the functional analysis of two putative genes, encoding 5-aminolevulinic acid synthase (ALAS) and acyl- CoA ligase (ACL). The amplified putative genes for ALAS and ACL were cloned into the E. coli expression vector pET- 32a(+) plasmid, following which the soluble recombinant ALAS and ACL proteins were purified through nickel-affinity column chromatography. Through HPLC analysis of the enzyme reaction mixture, we confirmed the products of putative ALAS and ACL reaction as 5-aminolevulinic acid (5-ALA) and 5-ALA-CoA, respectively. The optimal pH for the putative ALAS reaction was 7.5, and for putative ACL reaction was 7.0, as confirmed by the colorimetric assay. Furthermore, pyridoxal 5'-phosphate (PLP) was found to be an essential cofactor in the putative ALAS reaction, and ATP was a cofactor for the putative ACL catalysis. Finally, we also confirmed that the simultaneous treatment of putative ACL and putative ALAS enzymes resulted in the production of C5N compound from 5-ALA.


Assuntos
5-Aminolevulinato Sintetase/metabolismo , Vias Biossintéticas/genética , Coenzima A Ligases/metabolismo , Ciclopentanos/metabolismo , Streptomycetaceae/enzimologia , Streptomycetaceae/metabolismo , 5-Aminolevulinato Sintetase/genética , Clonagem Molecular , Coenzima A Ligases/genética , Coenzimas/análise , Estabilidade Enzimática , Escherichia coli/genética , Escherichia coli/metabolismo , Expressão Gênica , Vetores Genéticos , Concentração de Íons de Hidrogênio , Plasmídeos , Proteínas Recombinantes/química , Proteínas Recombinantes/genética , Proteínas Recombinantes/isolamento & purificação , Proteínas Recombinantes/metabolismo , Streptomycetaceae/genética
14.
J Antibiot (Tokyo) ; 71(10): 854-861, 2018 10.
Artigo em Inglês | MEDLINE | ID: mdl-29973681

RESUMO

ß-Carboline alkaloids and related compounds show a broad spectrum of biological activities. We previously identified new members of the ß-carboline alkaloid family by using an engineered Kitasatospora setae strain and a heterologous Streptomyces host expressing the plausible biosynthetic genes, including the hypothetical gene kse_70640 (kslB). Here, we elucidated the chemical structure of a new tetrahydro-ß-carboline compound (named kitasetalic acid) that appeared in a heterologous Streptomyces host expressing the kslB gene alone. Kitasetalic acid suppressed the expression of glucose-regulated protein 78 (GRP78) without inducing cell death. This is the first report to show that a tetrahydro-ß-carboline compound regulates the expression of the GRP78 protein in cancer cell lines.


Assuntos
Carbolinas/metabolismo , Engenharia Genética , Glucose/farmacologia , Streptomycetaceae/metabolismo , Carbolinas/química , Carbolinas/farmacologia , Linhagem Celular , Escherichia coli/genética , Escherichia coli/metabolismo , Regulação da Expressão Gênica/efeitos dos fármacos , Proteínas de Choque Térmico/genética , Proteínas de Choque Térmico/metabolismo , Humanos , Estrutura Molecular , Streptomycetaceae/genética
15.
Proc Natl Acad Sci U S A ; 115(14): 3634-3639, 2018 04 03.
Artigo em Inglês | MEDLINE | ID: mdl-29563230

RESUMO

High-quality protein crystals meant for structural analysis by X-ray diffraction have been grown by various methods. The observation of dynamical diffraction in protein crystals is an interesting topic because dynamical diffraction generally occurs in perfect crystals such as Si crystals. However, to our knowledge, there is no report yet on protein crystals showing clear dynamical diffraction. We wonder whether the perfection of protein crystals might still be low compared with that of high-quality Si crystals. Here, we present observations of the oscillatory profile of rocking curves for protein crystals such as glucose isomerase crystals. The oscillatory profiles are in good agreement with those predicted by the dynamical theory of diffraction. We demonstrate that dynamical diffraction occurs even in protein crystals. This suggests the possibility of the use of dynamical diffraction for the determination of the structure and charge density of proteins.


Assuntos
Aldose-Cetose Isomerases/química , Bioquímica/métodos , Cristalização/métodos , Cristalografia por Raios X/métodos , Streptomycetaceae/enzimologia , Fenômenos Biomecânicos , Conformação Proteica , Streptomycetaceae/crescimento & desenvolvimento
16.
J Microbiol Immunol Infect ; 51(1): 45-54, 2018 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-27103501

RESUMO

BACKGROUND/PURPOSE: In this study, an acidophilic actinobacteria strain was used as a novel reducing agent for a single-step synthesis of nanostructure silver particles. We used a Streptacidiphilus durhamensis HGG16n isolate for efficient synthesis of bioactive silver nanoparticles [bio(AgNPs)] in an inexpensive, eco-friendly, and nontoxic manner. The obtained bio(AgNPs) exhibited unique physicochemical and biochemical properties. METHODS: Structural, morphological, and optical properties of the synthesized biocolloids were characterized by spectroscopy, dynamic light scattering, and electron microscopy approaches. The antimicrobial activity was evaluated using the well- and disc-diffusion methods. RESULTS: The obtained crystalline structure and stable biosynthesized silver nanoparticles ranged in size from 8 nm to 48 nm and were mostly spherical in shape. Antimicrobial assays of the silver nanoparticles against pathogenic bacteria showed the highest antimicrobial activity against Pseudomonas aeruginosa, Staphylococcus aureus, and Proteus mirabilis, followed by Escherichia coli, Klebsiella pneumoniae, and Bacillus subtilis. Moreover, the synergistic effect of bio(AgNPs) with various commercially available antibiotics was also evaluated. CONCLUSION: These results provide insight into the development of new antimicrobial agents along with synergistic enhancement of the antibacterial mechanism against clinical bacteria.


Assuntos
Anti-Infecciosos/metabolismo , Anti-Infecciosos/farmacologia , Nanopartículas Metálicas/química , Prata/metabolismo , Prata/farmacologia , Streptomycetaceae/metabolismo , Antibacterianos/química , Antibacterianos/farmacologia , Bactérias/efeitos dos fármacos , Escherichia coli/efeitos dos fármacos , Klebsiella pneumoniae/efeitos dos fármacos , Testes de Sensibilidade Microbiana , Proteus mirabilis/efeitos dos fármacos , Pseudomonas aeruginosa/efeitos dos fármacos , Staphylococcus aureus/efeitos dos fármacos
17.
Biotechnol J ; 13(1)2018 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-29076639

RESUMO

Streptomycetes are known for their inherent ability to produce pharmaceutically relevant secondary metabolites. Discovery of medically useful, yet novel compounds has become a great challenge due to frequent rediscovery of known compounds and a consequent decline in the number of relevant clinical trials in the last decades. A paradigm shift took place when the first whole genome sequences of streptomycetes became available, from which silent or "cryptic" biosynthetic gene clusters (BGCs) were discovered. Cryptic BGCs reveal a so far untapped potential of the microorganisms for the production of novel compounds, which has spurred new efforts in understanding the complex regulation between primary and secondary metabolism. This new trend has been accompanied with development of new computational resources (genome and compound mining tools), generation of various high-quality omics data, establishment of molecular tools, and other strain engineering strategies. They all come together to enable systems metabolic engineering of streptomycetes, allowing more systematic and efficient strain development. In this review, the authors present recent progresses within systems metabolic engineering of streptomycetes for uncovering their hidden potential to produce novel compounds and for the improved production of secondary metabolites.


Assuntos
Engenharia Metabólica/tendências , Streptomycetaceae/metabolismo , Biologia de Sistemas , Metabolismo Secundário/genética , Streptomycetaceae/genética
18.
J Antibiot (Tokyo) ; 70(10): 1000-1003, 2017 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-28951607

RESUMO

A novel actinobacterium, designated strain YIM 75704T, was isolated from a limestone quarry located at Gulbarga, Karnataka, India. The novel strain has showed typical morphological and chemotaxonomic characteristics of the family Streptomycetaceae. Comparison of 16S rRNA gene sequences indicated that this strain represents a novel member of the family Streptomycetaceae and exhibited 99.0% 16S rRNA gene sequence similarities with the type species of the recently described novel genus Allostreptomyces, that is, Allostreptomyces psammosilenae, whereas other species of Streptomyces were below 95% sequence similarity. The cell hydrolysates contained the LL-isomer of diaminopimelic acid and the predominant quinones were MK-9 (H6, H8 and H4). The polar lipid profile consisted of diphosphatidylglycerol, phosphatidylinositolmannosides and three unknown phospholipids. The DNA G+C content was 75.0 mol%. A polyphasic study of the strain with morphological, phenotypic, phylogenetic and with DNA-DNA hybridization evidence with related members showed that this strain represents novel species of Allostreptomyces for which the name Allostreptomyces indica sp. nov., is proposed. The type strain is YIM 75704T (= DSM 41985T=CCTCC AA 209051T= NCIM 5485T).


Assuntos
Microbiologia Ambiental , Streptomycetaceae/classificação , Streptomycetaceae/isolamento & purificação , Composição de Bases , Parede Celular/química , Análise por Conglomerados , Citosol/química , DNA Bacteriano/química , DNA Bacteriano/genética , DNA Ribossômico/química , DNA Ribossômico/genética , Ácido Diaminopimélico/análise , Índia , Hibridização de Ácido Nucleico , Fosfolipídeos/análise , Filogenia , Quinonas/análise , RNA Ribossômico 16S/genética , Análise de Sequência de DNA , Streptomycetaceae/genética
19.
Appl Microbiol Biotechnol ; 101(21): 7877-7888, 2017 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-28924834

RESUMO

The genome of Kitasatospora setae KM-6054, a soil actinomycete, has three genes encoding chitosanases belonging to GH46 family. The genes (csn1-3) were cloned in Streptomyces lividans and the corresponding enzymes were purified from the recombinant cultures. The csn2 clone yielded two proteins (Csn2BH and Csn2H) differing by the presence of a carbohydrate-binding domain. Sequence analysis showed that Csn1 and Csn2H were canonical GH46 chitosanases, while Csn3 resembled chitosanases from bacilli. The activity of the four chitosanases was tested in a variety of conditions and on diverse chitosan forms, including highly N-deacetylated chitosan or chitosan complexed with humic or polyphosphoric acid. Kinetic parameters were also determined. These tests unveiled the biochemical diversity among these chitosanases and the peculiarity of Csn3 compared with the other three enzymes. The observed biochemical diversity is discussed based on structural 3D models and sequence alignment. This is a first study of all the GH46 chitosanases produced by a single microbial strain.


Assuntos
Variação Genética , Glicosídeo Hidrolases/genética , Glicosídeo Hidrolases/metabolismo , Streptomycetaceae/enzimologia , Quitosana/metabolismo , Clonagem Molecular , Glicosídeo Hidrolases/classificação , Proteínas Recombinantes/genética , Proteínas Recombinantes/isolamento & purificação , Proteínas Recombinantes/metabolismo , Análise de Sequência de DNA , Streptomyces lividans/genética , Streptomyces lividans/isolamento & purificação , Streptomyces lividans/metabolismo
20.
ACS Chem Biol ; 12(8): 2008-2014, 2017 08 18.
Artigo em Inglês | MEDLINE | ID: mdl-28719183

RESUMO

Streptomyces virginiae phenylpyruvate decarboxylase (PPDC) has not been identified before. Two putative branched-chain α-keto acid dehydrogenase subunit genes bkdC and bkdD from S. virginiae are similar to halves of other PPDC coding sequences. We cloned and characterized them biochemically in this work. The two proteins formed a stable complex attested by pull-down assay, consistent with the finding that their soluble expression was obtained only when they were coexpressed in Escherichia coli. The subunits were redesignated as SvPPDCα and SvPPDCß, because the SvPPDCα/ß complex catalyzed the conversion of phenylpyruvate to phenylacetaldehyde, reflecting the nature of the enzyme. Moreover, mutations of conserved residues in either of the two subunits led to inactivation or decreased specific activity of the enzymatic reaction. All previously identified PPDCs are encoded by a single gene. Here, we identified a new type of PPDC that contains two subunits, which gives new insights into the PPDC family.


Assuntos
Carboxiliases/genética , Carboxiliases/metabolismo , Domínio Catalítico/genética , Streptomycetaceae/enzimologia , Streptomycetaceae/genética , Sequência de Aminoácidos , Carboxiliases/química , Ativação Enzimática/genética , Escherichia coli/genética , Regulação Bacteriana da Expressão Gênica , Mutação , Ácidos Fenilpirúvicos/metabolismo , Plasmídeos/genética , Plasmídeos/metabolismo , Alinhamento de Sequência
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