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1.
Nat Commun ; 11(1): 4202, 2020 08 21.
Artigo em Inglês | MEDLINE | ID: mdl-32826900

RESUMO

Antibiotic biosynthetic gene clusters (BGCs) produce bioactive metabolites that impart a fitness advantage to their producer, providing a mechanism for natural selection. This selection drives antibiotic evolution and adapts BGCs for expression in different organisms, potentially providing clues to improve heterologous expression of antibiotics. Here, we use phage-assisted continuous evolution (PACE) to achieve bioactivity-dependent adaptation of the BGC for the antibiotic bicyclomycin (BCM), facilitating improved production in a heterologous host. This proof-of-principle study demonstrates that features of natural bioactivity-dependent evolution can be engineered to access unforeseen routes of improving metabolic pathways and product yields.


Assuntos
Antibacterianos/biossíntese , Vias Biossintéticas/genética , Família Multigênica , Produtos Biológicos/metabolismo , Compostos Bicíclicos Heterocíclicos com Pontes/metabolismo , Clonagem Molecular , Escherichia coli , Regulação Bacteriana da Expressão Gênica , Engenharia Metabólica , Pseudomonas fluorescens/genética , Pseudomonas fluorescens/metabolismo
2.
J Med Microbiol ; 69(8): 1040-1048, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32692643

RESUMO

Given the increased reporting of multi-resistant bacteria and the shortage of newly approved medicines, researchers have been looking towards extreme and unusual environments as a new source of antibiotics. Streptomyces currently provides many of the world's clinical antibiotics, so it comes as no surprise that these bacteria have recently been isolated from traditional medicine. Given the wide array of traditional medicines, it is hoped that these discoveries can provide the much sought after core structure diversity that will be required of a new generation of antibiotics. This review discusses the contribution of Streptomyces to antibiotics and the potential of newly discovered species in traditional medicine. We also explore how knowledge of traditional medicines can aid current initiatives in sourcing new and chemically diverse antibiotics.


Assuntos
Antibacterianos/isolamento & purificação , Descoberta de Drogas/tendências , Microbiologia do Solo , Streptomyces/metabolismo , Animais , Antibacterianos/biossíntese , Cavernas/química , Invertebrados/química , Medicina Tradicional , Peptídeo Sintases/metabolismo , Plantas Medicinais/química , Policetídeo Sintases/metabolismo , Poríferos/química , Streptomyces/química , Streptomyces/enzimologia
3.
Int J Syst Evol Microbiol ; 70(5): 3076-3083, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-32228806

RESUMO

Strain ATCC 31180T was isolated from soil collected in Hyde Park, Massachusetts (USA), and found to produce the polyether antibiotic lasalocid. The name 'Streptomyces lasaliensis' has been in common use since 1974, without a recognized taxonomic description. The most closely related type cultures determined by rRNA gene sequence similarity were Streptomyces longwoodensis DSM 41677T (100 %) and Streptomyces galbus DSM 40089T (100 %). OrthoANI values with S. longwoodensis and S. galbus were 95.50 and 94.41 %, respectively. Chemotaxonomic characteristics supported inclusion within the genus Streptomyces. The cell wall peptidoglycan contained ll-diaminopimelic acid, and the major whole-cell sugars were glucose and ribose. Polar lipids were phosphatidylethanolamine, diphosphatidylglycerol, phosphatidylinositol, phosphatidylglycerol, one unidentified lipid and one unidentified glycolipid. The major menaquinones detected were MK9(H4), MK9(H6) and MK9(H8). The major cellular fatty acids were anteiso-C15 : 0, anteiso-C17 : 0, iso-C16 : 0, iso-C15 : 0 and anteiso-C17 : 1. Its DNA had a G+C content of 72.6 %. Differentiation of ATCC 31180T from the closely related species was evident from digital DNA-DNA hybridization values of 61.80 and 56.90 % for S. longwoodensis and S. galbus respectively. Significant differences were seen in the polyphasic phenotypic analyses. ATCC 31180T produced lasalocid, grew from 10 to 45 °C, pH4-8 and in the presence of 0-10 % NaCl, 0.01 % NaN3 and 1 % phenol. Melanin was produced; H2S and indole were not. Nitrate was not reduced. Spore chains were retinaculum-apertum and spore surfaces were smooth. Spore colour, mycelia colour and soluble pigment production were medium-dependent. The proposed name is Streptomyces lasalocidi sp. nov.; the type strain being ATCC 31180T (=NRRL 3382T=DSM 46487T).


Assuntos
Antibacterianos/biossíntese , Lasalocida/biossíntese , Filogenia , Microbiologia do Solo , Streptomyces/classificação , Técnicas de Tipagem Bacteriana , Composição de Bases , DNA Bacteriano/genética , Ácido Diaminopimélico/análise , Ácido Diaminopimélico/química , Ácidos Graxos/química , Massachusetts , Hibridização de Ácido Nucleico , Peptidoglicano/química , Fosfolipídeos/química , RNA Ribossômico 16S/genética , Análise de Sequência de DNA , Streptomyces/isolamento & purificação , Vitamina K 2/análogos & derivados , Vitamina K 2/química
4.
Microbes Environ ; 35(2)2020.
Artigo em Inglês | MEDLINE | ID: mdl-32269203

RESUMO

More than 3,000 isolates of fluorescent pseudomonads have been collected from plant roots in Japan and screened for the presence of antibiotic-synthesizing genes. In total, 927 hydrogen cyanide (HCN)-, 47 2,4-diacetylphloroglucinol (PHL)-, 6 pyoluteorin (PLT)-, 14 pyrrolnitrin (PRN)-, and 8 phenazine (PHZ)-producing isolates have been detected. A cluster analysis (≥99% identity) identified 10 operational taxonomic units (OTUs) in antibiotic biosynthesis gene-possessing pseudomonads. OTU HLR (PHL, PLT, and PRN) contained four antibiotics: HCN, PHL, PLT, and PRN, while OTU RZ (PRN and PHZ) contained three: HCN, PRN, and PHZ. OTU H1, H2, H3, H4, H5, H6, and H7 (PHL1-7) contained two antibiotics: HCN and PHL, while OTU H8 (PHL8) contained one: PHL. Isolates belonging to OTU HLR and RZ suppressed damping-off disease in cabbage seedlings caused by Rhizoctonia solani. Effective strains belonging to OTU HLR and RZ were related to Pseudomonas protegens and Pseudomonas chlororaphis, respectively. Antibiotic biosynthesis gene-possessing fluorescent pseudomonads are distributed among different geographical sites in Japan and plant species.


Assuntos
Antibacterianos/biossíntese , Fluorescência , Pseudomonas/classificação , Rizosfera , Agentes de Controle Biológico , Genes Bacterianos , Variação Genética , Japão , Raízes de Plantas/microbiologia , Pseudomonas/metabolismo , Pseudomonas fluorescens/genética , RNA Ribossômico 16S/genética , Microbiologia do Solo
5.
Microbiol Res ; 236: 126466, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-32193126

RESUMO

Since the advent of biologics in human welfare various bio-molecules have been explored. Different bacterial exopolysaccharides have proved their worth in many industrial and commercial applications. In this perspective, while exploring a surfactant exopolysaccharide of Ochrobactrum pseudintermedium C1, it is strikingly observed that it possesses a potent antibacterial property which encourages its bio-medical applications. Following isolation and purification of the said exopolysaccharide, its structural configuration and functional attributes are studied by several analytical procedures involving FTIR, 13C- NMR, CHN-analysis, estimation of zeta potential, XRD-study and digital tensiometry. When treated with pathological samples in vitro, it distinctly elicits its antibacterial property by exhibiting a characteristic zone of inhibition. Combined with a standard antibiotic (like ciprofloxacin), it enhances the action of antibiotic also. Mechanism of its antibacterial action is evaluated by crystal violet entrapment assay with UV-vis spectrophotometry, bacterial cell viability assay by trypan blue staining and SEM study. Results show that its basic surfactant property, anionic character, crystalline nature and scaffolding architecture are supposed to facilitate its antibacterial property which is manifested by its capability of disrupting bacterial cell envelope causing eventual cell death. In the current global scenario, an increasing threat of antibiotic resistance is prevailing due to their indiscriminate use. If used as an adjuvant with a judicious dose of antibiotic, this bio-molecule might play a significant role in bio-medicine to combat such threat.


Assuntos
Antibacterianos/biossíntese , Antibacterianos/farmacologia , Ochrobactrum , Polissacarídeos Bacterianos/biossíntese , Tensoativos/metabolismo , Antibacterianos/metabolismo , Quimioterapia Adjuvante , Ciprofloxacino/farmacologia , Escherichia coli/efeitos dos fármacos , Humanos , Técnicas In Vitro , Testes de Sensibilidade Microbiana , Ochrobactrum/metabolismo , Polissacarídeos Bacterianos/química , Polissacarídeos Bacterianos/metabolismo , Staphylococcus aureus/efeitos dos fármacos
6.
J Agric Food Chem ; 68(8): 2373-2380, 2020 Feb 26.
Artigo em Inglês | MEDLINE | ID: mdl-32013409

RESUMO

Pseudomonas chlororaphis have been demonstrated to be environmentally friendly biocontrol strains, and most of them can produce phenazine compounds. Phenazine-1,6-dicarboxylic acid (PDC), with a potential antibacterial activity, is generally found in Streptomyces but not in Pseudomonas. The present study aimed to explore the feasibility of PDC synthesis and the function of PhzG in Pseudomonas. A PDC producer was constructed by replacing phzG in P. chlororaphis with lphzG from Streptomyces lomondensis. Through gene deletion, common start codon changing, gene silence, and in vitro assay, our result revealed that the yield of PDC in P. chlororaphis is associated with the relative expression of phzG to phzA and phzB. In addition, it is found that PDC can be spontaneously synthesized without PhzG. This study provides an efficient way for PDC production and promotes a better understanding of PhzG function in PDC biosynthesis. Moreover, this study gives an alternative opportunity for developing new antibacterial biopesticides.


Assuntos
Antibacterianos/biossíntese , Proteínas de Bactérias/metabolismo , Fenazinas/metabolismo , Pseudomonas chlororaphis/genética , Pseudomonas chlororaphis/metabolismo , Sequência de Aminoácidos , Proteínas de Bactérias/química , Proteínas de Bactérias/genética , Deleção de Genes , Dados de Sequência Molecular , Pseudomonas chlororaphis/enzimologia , Alinhamento de Sequência
7.
Mar Biotechnol (NY) ; 22(2): 308-316, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-32048095

RESUMO

The knowledge of antibiotics produced by Archaea (archaeocins) is still limited. So far, only two types of archaeocins are known: (i) sulfolobicins, produced by the extremely thermophilic Sulfolobus spp. and (ii) haloarcheocins, produced by halophilic archaea. Haloarcheocins were first discovered in the 1980s, but most of their characterisation was solely based on supernatant-based assays. Only a few were successfully purified and sequenced, and even fewer have a proposed biosynthetic model. Furthermore, their mode of action, ecological role and biotechnological potential are still to be explored. Haloarcheocin C8 (HalC8) is the best well-characterised haloarcheocin. We applied an approach of comparative genomics in order to go a step further in the knowledge of their biosynthetic clusters as well as the clusters encoding HalC8-like peptides. These peptides can be classified, at least, into 4 different clades, and there is low gene conservation between them. However, the putative function of some proteins is conserved. These include uncharacterized major facilitator superfamily proteins, transmembrane peptides, DNA-binding transcriptional regulators and proteins with extracellular domains. Our analysis reinforces the association of these proteins with HalC8/HalC8-like biosynthesis. Their functionality is unknown, and, in an era where it is known that haloarchaea are not confined to high salt habitats, the advance in the knowledge of their specialised metabolites will be imperative.


Assuntos
Antibacterianos/metabolismo , Archaea/genética , Genômica , Antibacterianos/biossíntese , Antibacterianos/química , Archaea/metabolismo , Proteínas Arqueais/biossíntese , Proteínas Arqueais/genética , Proteínas Arqueais/metabolismo , Peptídeos/genética , Peptídeos/metabolismo
8.
Appl Environ Microbiol ; 86(9)2020 04 17.
Artigo em Inglês | MEDLINE | ID: mdl-32086301

RESUMO

The four regulatory genes fscR1 to fscR4 in Streptomyces sp. strain FR-008 form a genetic arrangement that is widely distributed in macrolide-producing bacteria. Our previous work has demonstrated that fscR1 and fscR4 are critical for production of the polyene antibiotic candicidin. In this study, we further characterized the roles of the other two regulatory genes, fscR2 and fscR3, focusing on the relationship between these four regulatory genes. Disruption of a single or multiple regulatory genes did not affect bacterial growth, but transcription of genes in the candicidin biosynthetic gene cluster decreased, and candicidin production was abolished, indicating a critical role for each of the four regulatory genes, including fscR2 and fscR3, in candicidin biosynthesis. We found that fscR1 to fscR4, although differentially expressed throughout the growth phase, displayed similar temporal expression patterns, with an abrupt increase in the early exponential phase, coincident with initial detection of antibiotic production in the same phase. Our data suggest that the four regulatory genes fscR1 to fscR4 have various degrees of control over structural genes in the biosynthetic cluster under the conditions examined. Extensive transcriptional analysis indicated that complex regulation exists between these four regulatory genes, forming a regulatory network, with fscR1 and fscR4 functioning at a lower level. Comprehensive cross-complementation analysis indicates that functional complementation is restricted among the four regulators and unidirectional, with fscR1 complementing the loss of fscR3 or -4 and fscR4 complementing loss of fscR2 Our study provides more insights into the roles of, and the regulatory network formed by, these four regulatory genes controlling production of an important pharmaceutical compound.IMPORTANCE The regulation of antibiotic biosynthesis by Streptomyces species is complex, especially for biosynthetic gene clusters with multiple regulatory genes. The biosynthetic gene cluster for the polyene antibiotic candicidin contains four consecutive regulatory genes, which encode regulatory proteins from different families and which form a subcluster within the larger biosynthetic gene cluster in Streptomyces sp. FR-008. Syntenic arrangements of these regulatory genes are widely distributed in polyene gene clusters, such as the amphotericin and nystatin gene clusters, suggesting a conserved regulatory mechanism controlling production of these clinically important medicines. However, the relationships between these multiple regulatory genes are unknown. In this study, we determined that each of these four regulatory genes is critical for candicidin production. Additionally, using transcriptional analyses, bioassays, high-performance liquid chromatography (HPLC) analysis, and genetic cross-complementation, we showed that FscR1 to FscR4 comprise a hierarchical regulatory network that controls candicidin production and is likely representative of how expression of other polyene biosynthetic gene clusters is controlled.


Assuntos
Antibacterianos/biossíntese , Proteínas de Bactérias/metabolismo , Candicidina/biossíntese , Regulação Bacteriana da Expressão Gênica , Streptomyces/metabolismo , Fatores de Transcrição/metabolismo , Proteínas de Bactérias/genética , Diterpenos , Genes Bacterianos , Genes Reguladores , Streptomyces/genética , Fatores de Transcrição/genética
9.
Microb Cell Fact ; 19(1): 3, 2020 Jan 06.
Artigo em Inglês | MEDLINE | ID: mdl-31906943

RESUMO

Using an established CRISPR-Cas mediated genome editing technique for streptomycetes, we explored the combinatorial biosynthesis potential of the auroramycin biosynthetic gene cluster in Streptomyces roseosporous. Auroramycin is a potent anti-MRSA polyene macrolactam. In addition, auroramycin has antifungal activities, which is unique among structurally similar polyene macrolactams, such as incednine and silvalactam. In this work, we employed different engineering strategies to target glycosylation and acylation biosynthetic machineries within its recently elucidated biosynthetic pathway. Auroramycin analogs with variations in C-, N- methylation, hydroxylation and extender units incorporation were produced and characterized. By comparing the bioactivity profiles of five of these analogs, we determined that unique disaccharide motif of auroramycin is essential for its antimicrobial bioactivity. We further demonstrated that C-methylation of the 3, 5-epi-lemonose unit, which is unique among structurally similar polyene macrolactams, is key to its antifungal activity.


Assuntos
Antibacterianos/biossíntese , Antifúngicos/química , Vias Biossintéticas/genética , Engenharia Metabólica/métodos , Streptomyces/genética , Antibacterianos/química , Antibacterianos/farmacologia , Antifúngicos/farmacologia , Sistemas CRISPR-Cas , Edição de Genes/métodos , Staphylococcus aureus Resistente à Meticilina/efeitos dos fármacos , Testes de Sensibilidade Microbiana , Polienos/química , Streptomyces/metabolismo
10.
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
11.
BMC Genomics ; 21(1): 21, 2020 Jan 06.
Artigo em Inglês | MEDLINE | ID: mdl-31906847

RESUMO

BACKGROUND: Disease resistance is an important factor that impacts rice production. However, the mechanisms underlying rice disease resistance remain to be elucidated. RESULTS: Here, we show that a robust set of genes has been defined in rice response to the infections of Xanthomonas oryzae pv. oryzae (Xoo) and Magnaporthe oryzae (Mor). We conducted a comprehensive analysis of the available microarray data from a variety of rice samples with inoculation of Xoo and Mor. A set of 12,932 genes was identified to be regulated by Xoo and another set of 2709 Mor-regulated genes was determined. GO enrichment analysis of the regulated genes by Xoo or Mor suggested mitochondrion may be an arena for the up-regulated genes and chloroplast be another for the down-regulated genes by Xoo or Mor. Cytokinin-related processes were most frequently repressed by Xoo, while processes relevant to jasmonic acid and abscisic acid were most frequently activated by Xoo and Mor. Among genes responsive to Xoo and Mor, defense responses and diverse signaling pathways were the most frequently enriched resistance mechanisms. InterPro annotation showed the zinc finger domain family, WRKY proteins, and Myb domain proteins were the most significant transcription factors regulated by Xoo and Mor. KEGG analysis demonstrated pathways including 'phenylpropanoid biosynthesis', 'biosynthesis of antibiotics', 'phenylalanine metabolism', and 'biosynthesis of secondary metabolites' were most frequently triggered by Xoo and Mor, whereas 'circadian rhythm-plant' was the most frequent pathway repressed by Xoo and Mor. CONCLUSIONS: The genes identified here represent a robust set of genes responsive to the infections of Xoo and Mor, which provides an overview of transcriptional reprogramming during rice defense against Xoo and Mor infections. Our study would be helpful in understanding the mechanisms of rice disease resistance.


Assuntos
Resistência à Doença/genética , Perfilação da Expressão Gênica/métodos , Regulação da Expressão Gênica de Plantas , Oryza/genética , Doenças das Plantas/genética , Ácido Abscísico/metabolismo , Antibacterianos/biossíntese , Ciclopentanos/metabolismo , Interações Hospedeiro-Patógeno , Magnaporthe/fisiologia , Oryza/metabolismo , Oryza/microbiologia , Oxilipinas/metabolismo , Fenilalanina/metabolismo , Doenças das Plantas/microbiologia , Transdução de Sinais/genética , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo , Xanthomonas/fisiologia
12.
mSphere ; 5(1)2020 01 08.
Artigo em Inglês | MEDLINE | ID: mdl-31915225

RESUMO

Mark Walker studies the biosynthesis and engineering of bacterial natural products with the long-term goal of identifying new antibiotic compounds. In this mSphere of Influence, he reflects on how "Direct cloning and refactoring of a silent lipopeptide biosynthetic gene cluster yields the antibiotic taromycin A" by K. Yamanaka, K. A. Reynolds, R. D. Kersten, K. S. Ryan, et al. (Proc Natl Acad Sci USA 111:1957-1962, 2014, https://doi.org/10.1073/pnas.1319584111) impacted his thinking on using synthetic biology approaches to study natural product biosynthesis.


Assuntos
Produtos Biológicos/metabolismo , Vias Biossintéticas , Família Multigênica , Biologia Sintética , Antibacterianos/biossíntese , Bactérias/genética
13.
Sci Adv ; 6(3): eaay5781, 2020 01.
Artigo em Inglês | MEDLINE | ID: mdl-31998842

RESUMO

One of the hallmark behaviors of social groups is division of labor, where different group members become specialized to carry out complementary tasks. By dividing labor, cooperative groups increase efficiency, thereby raising group fitness even if these behaviors reduce individual fitness. We find that antibiotic production in colonies of Streptomyces coelicolor is coordinated by a division of labor. We show that S. coelicolor colonies are genetically heterogeneous because of amplifications and deletions to the chromosome. Cells with chromosomal changes produce diversified secondary metabolites and secrete more antibiotics; however, these changes reduced individual fitness, providing evidence for a trade-off between antibiotic production and fitness. Last, we show that colonies containing mixtures of mutants and their parents produce significantly more antibiotics, while colony-wide spore production remains unchanged. By generating specialized mutants that hyper-produce antibiotics, streptomycetes reduce the fitness costs of secreted secondary metabolites while maximizing the yield and diversity of these products.


Assuntos
Antibacterianos/biossíntese , Regulação Bacteriana da Expressão Gênica , Genes Bacterianos , Streptomyces/genética , Streptomyces/metabolismo , Heterogeneidade Genética , Genoma Bacteriano , Genômica/métodos , Mutação , Fenótipo , Proteoma , Metabolismo Secundário
14.
Mar Drugs ; 18(1)2020 Jan 03.
Artigo em Inglês | MEDLINE | ID: mdl-31947807

RESUMO

The synthesis of silver nanoparticles (AgNPs) by microorganisms recently gained a greater interest due to its potential to produce them in various sizes and morphologies. In this study, for AgNP biosynthesis, we used a new Pseudomonas strain isolated from a consortium associated with the Antarctic marine ciliate Euplotes focardii. After incubation of Pseudomonas cultures with 1 mM of AgNO3 at 22 °C, we obtained AgNPs within 24 h. Scanning electron (SEM) and transmission electron microscopy (TEM) revealed spherical polydispersed AgNPs in the size range of 20-70 nm. The average size was approximately 50 nm. Energy dispersive X-ray spectroscopy (EDS) showed the presence of a high intensity absorption peak at 3 keV, a distinctive property of nanocrystalline silver products. Fourier transform infrared (FTIR) spectroscopy found the presence of a high amount of AgNP-stabilizing proteins and other secondary metabolites. X-ray diffraction (XRD) revealed a face-centred cubic (fcc) diffraction spectrum with a crystalline nature. A comparative study between the chemically synthesized and Pseudomonas AgNPs revealed a higher antibacterial activity of the latter against common nosocomial pathogen microorganisms, including Escherichia coli, Staphylococcus aureus and Candida albicans. This study reports an efficient, rapid synthesis of stable AgNPs by a new Pseudomonas strain with high antimicrobial activity.


Assuntos
Antibacterianos/biossíntese , Euplotes/microbiologia , Nanopartículas Metálicas/química , Pseudomonas/metabolismo , Prata/química , Regiões Antárticas , Antibacterianos/farmacologia , Candida albicans/efeitos dos fármacos , Escherichia coli/efeitos dos fármacos , Química Verde/métodos , Nanopartículas Metálicas/administração & dosagem , Microscopia Eletrônica de Transmissão/métodos , Tamanho da Partícula , Prata/farmacologia , Espectroscopia de Infravermelho com Transformada de Fourier/métodos , Staphylococcus aureus/efeitos dos fármacos
15.
Microbiol Res ; 233: 126411, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31981905

RESUMO

In Streptomyces pristinaespiralis, the orphan histidine kinase (HK) PdtaS-p (encoded by SSDG_02492), which belongs to proteins of two-component systems (TCSs), plays an important role in both morphological differentiation and antibiotic biosynthesis. Owing to the isolated genetic organization of pdtaS-p, it is a challenge to identify its cognate response regulator (RR) and hampers the efforts to elucidate the regulation mechanism of PdtaS-p. In this study, based on bioinformatics analysis, we identify the cognate RR PdtaR-p (encoded by SSDG_04087) of PdtaS-p by phenotype similarity of gene deletion mutants as well as in vitro phosphor-transfer assay. We show that the mutants (ΔpdtaR-p and ΔpdtaS-p) exhibit almost the same phenotypical changes, showing a bald phenotype on MS agar and reduced pristinamycin biosynthesis. Further phosphor-transfer assay indicates that the phosphoryl group of HK PdtaS-p can be specifically transferred to RR PdtaR-p. Compared with the majority of RRs that harbor DNA-binding domains, PdtaR-p contains a putative ANTAR RNA-binding domain involved in controlling gene expression at the post-transcription level. Finally, we demonstrate that their ortholog from the model strain Streptomyces coelicolor, PdtaS-c/PdtaR-c, also regulates both morphological differentiation and antibiotics biosynthesis, suggesting that PdtaS-p/PdtaR-p-mediated molecular regulation may be conserved in the genus Streptomyces. To our knowledge, this is the first report describing the functional identification of ANTAR RNA-binding regulators in Streptomyces.


Assuntos
Antibacterianos/biossíntese , Proteínas de Bactérias/metabolismo , Histidina Quinase/metabolismo , Streptomyces/enzimologia , Proteínas de Bactérias/genética , Biologia Computacional , Deleção de Genes , Regulação Bacteriana da Expressão Gênica , Histidina Quinase/genética , Mutação , Fenótipo , Proteínas com Motivo de Reconhecimento de RNA/genética , Streptomyces/genética
16.
Microsc Res Tech ; 83(1): 72-80, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31617656

RESUMO

Nanoparticles as biomedicine has made a crucial role in health biotechnology. Different transition metals in various forms playing role in nanotechnological advances and biological applications. Silver as one of the nontoxic, safe inorganic antibacterial agents and can serve as replacement of antibiotics. Present research is based on biogenic synthesis of silver nanoparticles (Ag-NPs) as potential antibiotics from fungal metabolites of Penicillium oxalicum. We used different analytical techniques X-ray diffraction (XRD) and scanning electron microscopy (SEM) for characterization of biosynthesized silver nanoparticles. Furthermore, the antibacterial activity of biosynthesized silver nanoparticles was checked against Staphylococcus aureus, S. dysenteriae, and Salmonella typhi by using well diffusion method and UV visible spectrophotometer. Maximum zone of inhibition recorded against S. aureus, Shigella dysenteriae was 17.5 ± 0.5 mm (mm) for both species and 18.3 ± 0.60 mm for Salmonella typhi. The biosynthesized silver nanoparticles of P. oxalicum showed excellent antibacterial activity. It was concluded from our results that biosynthesized silver nanoparticles have significant potential and might be useful for a wide range of biological applications such as bactericidal agent against resistant bacteria, preventing infections, healing wounds, and anti-inflammation.


Assuntos
Antibacterianos/biossíntese , Antibacterianos/farmacologia , Nanopartículas Metálicas/toxicidade , Penicillium/metabolismo , Prata/metabolismo , Prata/farmacologia , Antibacterianos/química , Nanopartículas Metálicas/ultraestrutura , Testes de Sensibilidade Microbiana , Microscopia Eletrônica de Transmissão , Salmonella typhi/efeitos dos fármacos , Prata/química , Staphylococcus aureus/efeitos dos fármacos
17.
Acta Biochim Biophys Sin (Shanghai) ; 52(1): 91-96, 2020 Jan 02.
Artigo em Inglês | MEDLINE | ID: mdl-31833535

RESUMO

Distamycin (DST) is a well-characterized DNA minor groove binder with antivirus activity and antitumor potency. Two separate gene clusters (a 28-kb cluster and a 7-kb cluster) have recently been identified to coordinately encode the biosynthetic machinery of DST in Streptomyces netropsis. Here we report a gene cassette, which is linked to the aforementioned smaller dst gene cluster and plays an important role in the self-resistance to DST in S. netropsis. This cassette consists of three uncharacterized genes that might be implicated in DNA replication/repair. Knockout of the cassette led to the decrease in the production of DST, while heterologous expression of part of the cassette in S. lividans made it become resistant to both DST and mitomycin C, another DNA-binding agent. More interestingly, homologs of these three genes were found in genomes of other actinomyces that produce DNA-binding antibiotics, suggesting that a novel common mechanism in addition to pumping may enable these strains to resist the cytotoxic metabolites they produced.


Assuntos
Antibacterianos/farmacologia , Reparo do DNA/genética , Replicação do DNA/genética , Distamicinas/farmacologia , Farmacorresistência Bacteriana/genética , Genes Bacterianos/genética , Streptomyces/genética , Antibacterianos/biossíntese , Células Cultivadas , Proteínas de Ligação a DNA/biossíntese , Proteínas de Ligação a DNA/farmacologia , Distamicinas/biossíntese , Escherichia coli/genética , Técnicas de Inativação de Genes , Mitomicina/farmacologia , Família Multigênica/genética , Streptomyces/efeitos dos fármacos , Streptomyces lividans/efeitos dos fármacos
18.
J Biosci Bioeng ; 129(2): 140-145, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31564502

RESUMO

Regulation of secondary metabolism involves complex interactions of both pathway-specific regulators and global regulators, which may trigger or repress the expression of genes involved in antibiotic biosynthesis. Similarly, many of these global regulatory proteins belong to two-component systems. In this study, a new two-component system (TCS) AfrQ1Q2 homologous to AfsQ1Q2 of Streptomyces coelicolor was acquired from the genome sequence of Streptomyces rimosus M4018 by using bioinformatics analysis. RT-PCR results showed co-transcription of afrQ1 (RR) and afrQ2 (HK) in S. rimosus. Consequently, the significant enhancement in oxytetracycline (OTC) yield in afrQ1-disrupted mutant was observed when cultivated in the defined minimal medium (MM) with glycine as the sole nitrogen source. In order to further investigate the regulation mechanism of AfrQ1Q2 in OTC production, the transcriptional levels of five biosynthesis and regulation related genes such as oxyB, otrB, otcG, otcR and otrC were tested by qRT-PCR, which indicated a significantly up-regulatory trend in the afrQ1-disrupted mutant. Meanwhile, a down-regulatory trend of each gene was tested in the complementary mutant as compared to wild type M4018. Moreover, these selected five genes were positively correlated with OTC production. Conclusively, these findings suggested that the TCS AfrQ1Q2 could be one of the global regulators, which negatively regulates OTC production via activating pathway specific regulators in S. rimosus M4018.


Assuntos
Antibacterianos/biossíntese , Oxitetraciclina/biossíntese , Streptomyces rimosus/metabolismo , Sequência de Bases , Genoma Bacteriano , Mutação , Streptomyces rimosus/genética
19.
J Agric Food Chem ; 68(2): 561-566, 2020 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-31840510

RESUMO

2-Hydroxyphenazine (2-OH-PHZ) is an effective biocontrol antibiotic secreted by Pseudomonas chlororaphis GP72AN and is transformed from phenazine-1-carboxylic acid (PCA). PCA is the main component of the recently registered biopesticide "Shenqinmycin". Previous research showed that 2-OH-PHZ was better in controlling wheat take-all disease than PCA; however, 2-OH-PHZ production was low under natural conditions. Herein, we confirmed that PCA induced reactive oxygen species in its host P. chlororaphis GP72AN and that the addition of DTT improved PCA production by 1.8-fold, whereas the supplementation of K3[Fe(CN)6] and H2O2 increased the conversion rate of PCA to 2-OH-PHZ. Finally, a two-stage fermentation strategy combining the addition of DTT at 12 h and H2O2 at 24 h enhanced 2-OH-PHZ production. Taken together, the two-stage fermentation strategy was designed to enhance 2-OH-PHZ production for the first time, and it provided a valuable reference for the fermentation of other antibiotics.


Assuntos
Antibacterianos/biossíntese , Glicerol/metabolismo , Microbiologia Industrial/métodos , Pseudomonas chlororaphis/metabolismo , Proteínas de Bactérias/metabolismo , Meios de Cultura/química , Meios de Cultura/metabolismo , Fermentação , Peróxido de Hidrogênio/metabolismo , Fenazinas/metabolismo , Espécies Reativas de Oxigênio/metabolismo
20.
J Antibiot (Tokyo) ; 73(1): 28-34, 2020 01.
Artigo em Inglês | MEDLINE | ID: mdl-31605027

RESUMO

Within the framework of our effort to discover new bioactive metabolites from Gram-negative bacteria, trinickiabactin (1) was isolated from the plant pathogenic strain Trinickia caryophylli DSM 50341. Whole genome sequencing allowed the identification of its biosynthetic gene cluster. The structure of 1 bears a rare diazeniumdiolate ligand system and was elucidated by a combination of NMR- and MS-spectroscopic techniques and bioinformatics. Trinickiabactin was found to be antibacterial toward several Gram-negative bacteria (MIC values ranged from 3.5 to 34.0 µg ml-1).


Assuntos
Antibacterianos/biossíntese , Antibacterianos/química , Doenças das Plantas/microbiologia , Proteobactérias/química , Antibacterianos/farmacologia , Simulação por Computador , Descoberta de Drogas , Bactérias Gram-Negativas/efeitos dos fármacos , Espectroscopia de Ressonância Magnética , Testes de Sensibilidade Microbiana , Família Multigênica , Proteobactérias/genética
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