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1.
Artigo em Inglês | MEDLINE | ID: mdl-32374252

RESUMO

Three presumptive Modestobacter strains isolated from a high altitude Atacama Desert soil were the subject of a polyphasic study. The isolates, strains 1G4T, 1G51 and 1G52, were found to have chemotaxonomic and morphological properties that were consistent with their assignment to the genus Modestobacter. They formed a well supported clade in Modestobacter 16S rRNA gene trees and were most closely related to the type strain of 'Modestobacter excelsi' (99.8-99.9% similarity). They were also closely related to the type strains of Modestobacter caceresii (99.6 % similarity), Modestobacter italicus (99.7-99.9% similarity), Modestobacter lacusdianchii (98.4-99.2% similarity), Modestobacter marinus (99.4-99.5% similarity) and Modestobacter roseus (99.3-99.5% similarity), but were distinguished from their closest relatives by a combination of phenotypic features. Average nucleotide identity and digital DNA:DNA hybridization similarities drawn from comparisons of draft genome sequences of isolate 1G4T and its closest phylogenetic neighbours mentioned above, were well below the threshold used to assign closely related strains to the same species. The close relationship between isolate 1G4T and the type strain of M. excelsi was showed in a phylogenomic tree containing representative strains of family Geodermatophilaceae. The draft genome sequence of isolate 1G4T (size 5.18 Kb) was shown to be rich in stress related genes providing further evidence that the abundance of Modestobacter propagules in Atacama Desert habitats reflects their adaptation to the harsh environmental conditions prevalent in this biome. In light of all of these data it is proposed that the isolates be assigned to a novel species in the genus Modestobacter. The name proposed for this taxon is Modestobacter altitudinis sp. nov., with isolate 1G4T (=DSM 107534T=PCM 3003T) as the type strain.

2.
Syst Appl Microbiol ; 43(1): 126051, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31892483

RESUMO

A polyphasic study was undertaken to establish the taxonomic status of three Modestobacter strains isolated from a high altitude Atacama Desert soil. The isolates, strains 1G6T, 1G14 and 1G50, showed chemotaxonomic and morphological properties characteristic of members of the genus Modestobacter. The peptidoglycan contained meso-diaminopimelic acid, the whole cell sugars were glucose and ribose (diagnostic sugars) and arabinose, the predominant menaquinone was MK-9(H4), polar lipid patterns contained diphosphatidylglycerol, glycophosphatidylinositol, phosphatidylethanolamine (diagnostic component), phosphatidylglycerol and phosphatidylinositol while whole cellular fatty acid profiles consisted of complex mixtures of saturated, unsaturated iso- and anteiso-components. The isolates were shown to have different BOX-PCR fingerprint and physiological profiles. They formed a distinct phyletic line in Modestobacter 16S rRNA gene trees, were most closely related to the type strain of Modestobacter italicus (99.9 % similarity) but were distinguished from this and other closely related Modestobacter type strains using a combination of phenotypic properties. Average nucleotide identity and digital DNA:DNA hybridization similarities between the draft genome sequences of isolate 1G6T and M. italicus BC 501T were 90.9 % and 42.3 %, respectively, indicating that they belong to different species. Based on these phenotypic and genotypic data it is proposed that the isolates be assigned to a novel species in the genus Modestobacter, namely as Modestobacter excelsi with isolate 1G6T (=DSM 107535T =PCM 3004T) as the type strain. Analysis of the whole genome sequence of M. excelsi 1G6T (genome size of 5.26 Mb) showed the presence of genes and gene clusters that encode for properties that are in tune with its adaptation to extreme environmental conditions that prevail in the Atacama Desert biome.


Assuntos
Actinobacteria/classificação , Actinobacteria/fisiologia , Clima Desértico , Microbiologia do Solo , Actinobacteria/química , Actinobacteria/citologia , Altitude , DNA Bacteriano/genética , Ácidos Graxos/análise , Genoma Bacteriano/genética , Hibridização de Ácido Nucleico , Peptidoglicano/química , Fosfolipídeos/química , Filogenia , RNA Ribossômico 16S/genética , Análise de Sequência de DNA , Especificidade da Espécie , Estresse Fisiológico/genética , Vitamina K 2/química
3.
Int J Syst Evol Microbiol ; 69(11): 3426-3436, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31395106

RESUMO

A Micromonospora strain, designated 5R2A7T, isolated from a high altitude Atacama Desert soil was examined by using a polyphasic approach. Strain 5R2A7T was found to have morphological, chemotaxonomic and cultural characteristics typical of members of the genus Micromonospora. The cell wall contains meso- and hydroxy-diaminopimelic acid, the major whole-cell sugars are glucose, ribose and xylose, the predominant menaquinones MK-10(H4), MK-10(H6), MK-10(H8) and MK-9(H6), the major polar lipids diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylinositol and an unknown glycolipid, and the predominant cellular fatty acids iso-C16 : 0, iso-C15 : 0 and 10-methyl C17 : 0. The digital genomic DNA G+C content is 72.3 mol%. Phylogenetic analysis of the 16S rRNA gene sequence indicated that strain 5R2A7T was closely related to Micromonospora coriariae DSM 44875T (99.8 %) and Micromonospora cremea CR30T (99.7 %), and was separated readily from the latter, its closest phylogenetic neighbour, based on gyrB and multilocus sequence data, by low average nucleotide identity (92.59 %) and in silico DNA-DNA relatedness (51.7 %) values calculated from draft genome assemblies and by a range of chemotaxonomic and phenotypic properties. Consequently, strain 5R2A7T is considered to represent a novel species of Micromonospora for which the name Micromonospora acroterricola sp. nov. is proposed. The type strain is 5R2A7T (=LMG 30755T=CECT 9656T).


Assuntos
Altitude , Clima Desértico , Micromonospora/classificação , Filogenia , Microbiologia do Solo , Técnicas de Tipagem Bacteriana , Composição de Bases , Parede Celular/química , Chile , DNA Bacteriano/genética , Ácido Diaminopimélico/química , Ácidos Graxos/química , Glicolipídeos/química , Micromonospora/isolamento & purificação , Hibridização de Ácido Nucleico , Fosfolipídeos/química , RNA Ribossômico 16S/genética , Análise de Sequência de DNA , Vitamina K 2/química
4.
J Clin Med ; 8(3)2019 Mar 10.
Artigo em Inglês | MEDLINE | ID: mdl-30857367

RESUMO

The chemical vapor deposition (CVD) method has been used to produce dispersed silver nanoparticles (AgNPs) on the surface of titanium alloy (Ti6Al4V) and nanotubular modified titanium alloys (Ti6Al4V/TNT5), leading to the formation of Ti6Al4V/AgNPs and Ti6Al4V/TNT5/AgNPs systems with different contents of metallic silver particles. Their surface morphology and silver particles arrangement were characterized by scanning electron microscopy (SEM), energy dispersive X-ray spectrometry (EDS), and atomic force microscopy (AFM). The wettability and surface free energy of these materials were investigated on the basis of contact angle measurements. The degree of silver ion release from the surface of the studied systems immersed in phosphate buffered saline solution (PBS) was estimated using inductively coupled plasma ionization mass spectrometry (ICP-MS). The biocompatibility of the analyzed materials was estimated based on the fibroblasts and osteoblasts adhesion and proliferation, while their microbiocidal properties were determined against Gram-positive and Gram-negative bacteria, and yeasts. The results of our works proved the high antimicrobial activity and biocompatibility of all the studied systems. Among them, Ti6Al4V/TNT5/0.6AgNPs contained the lowest amount of AgNPs, but still revealed optimal biointegration properties and high biocidal properties. This is the biomaterial that possesses the desired biological properties, in which the potential toxicity is minimized by minimizing the number of silver nanoparticles.

5.
Artigo em Inglês | MEDLINE | ID: mdl-30912480

RESUMO

Urinary tract infections (UTIs) have been frequently reported from different parts of the world. The current knowledge on distribution of causative agents of urinary infections and antibiotics susceptibility pattern is essentially required. In the present study, total 351 uropathogenic bacteria were isolated; among them most prevalent were Escherichia coli (75%), followed by Pseudomonas aeruginosa (8%), Proteus mirabilis (6%), Klebsiella pneumoniae (4%), Staphylococcus aureus (4%) and Enterococcus faecalis (3%). Most isolates of uropathogenic bacteria showed resistance to amoxicillin and trimethoprim, followed by chloramphenicol and kanamycin. Biosynthesis of sulfur nanoparticles (SNPs) was performed by co-precipitation method using sodium thiosulfate in presence of Catharanthus roseus leaf extract. The characterization data showed that SNPs were polydispersed, spherical in shape with size range of 20-86 nm and having negative zeta potential of -9.24 mV. The potential antibacterial activity was observed for SNPs alone and in combination with antibiotics particularly amoxicillin and trimethoprim against majority of the uropathogens. The synergistic effect yielded increase in fold area with high activity index against tested uropathogens. Based on overall results, it can be recommended to use SNPs for the management of UTI alone and also in combination with antibiotics.


Assuntos
Antibacterianos/farmacologia , Farmacorresistência Bacteriana Múltipla/efeitos dos fármacos , Nanopartículas/química , Enxofre/farmacologia , Infecções Urinárias/microbiologia , Antibacterianos/química , Sinergismo Farmacológico , Escherichia coli/efeitos dos fármacos , Escherichia coli/isolamento & purificação , Humanos , Klebsiella pneumoniae/efeitos dos fármacos , Klebsiella pneumoniae/isolamento & purificação , Testes de Sensibilidade Microbiana , Proteus mirabilis/efeitos dos fármacos , Proteus mirabilis/isolamento & purificação , Pseudomonas aeruginosa/efeitos dos fármacos , Pseudomonas aeruginosa/isolamento & purificação , Enxofre/química
6.
Antonie Van Leeuwenhoek ; 111(8): 1375-1387, 2018 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-29480426

RESUMO

Innovative procedures were used to selectively isolate small numbers of Micromonospora strains from extreme hyper-arid and high altitude Atacama Desert soils. Micromonosporae were recognised on isolation plates by their ability to produce filamentous microcolonies that were strongly attached to the agar. Most of the isolates formed characteristic orange colonies that lacked aerial hyphae and turned black on spore formation, whereas those from the high altitude soil were dry, blue-green and covered by white aerial hyphae. The isolates were assigned to seven multi- and eleven single-membered groups based on BOX-PCR profiles. Representatives of the groups were assigned to either multi-membered clades that also contained marker strains or formed distinct phyletic lines in the Micromonospora 16S rRNA gene tree; many of the isolates were considered to be putatively novel species of Micromonospora. Most of the isolates from the high altitude soils showed activity against wild type strains of Bacillus subtilis and Pseudomonas fluorescens while those from the rhizosphere of Parastrephia quadrangulares and from the Lomas Bayas hyper-arid soil showed resistance to UV radiation.


Assuntos
Clima Desértico , Micromonospora/classificação , Micromonospora/isolamento & purificação , Filogenia , Microbiologia do Solo , Chile , DNA Bacteriano/genética , Variação Genética , Genoma Bacteriano , Micromonospora/genética , Micromonospora/crescimento & desenvolvimento , RNA Ribossômico 16S/genética
7.
World J Microbiol Biotechnol ; 34(2): 23, 2018 Jan 05.
Artigo em Inglês | MEDLINE | ID: mdl-29305718

RESUMO

We report synthesis of silver nanoparticles (AgNPs) from Streptomyces xinghaiensis OF1 strain, which were characterised by UV-Vis and Fourier transform infrared spectroscopy, Zeta sizer, Nano tracking analyser, and Transmission electron microscopy. The antimicrobial activity of AgNPs alone, and in combination with antibiotics was evaluated against bacteria, namely Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus and Bacillus subtilis, and yeasts viz., Candida albicans and Malassezia furfur by using micro-dilution method. The minimum inhibitory concentration (MIC) and minimum biocidal concentration of AgNPs against bacterial and yeast strains were determined. Synergistic effect of AgNPs in combination with antibacterial and antifungal antibiotics was determined by FIC index. In addition, MTT assay was performed to study cytotoxicity of AgNPs alone and in combination with antibiotics against mouse fibroblasts and HeLa cell line. Biogenic AgNPs were stable, spherical, small, polydispersed and capped with organic compounds. The variable antimicrobial activity of AgNPs was observed against tested bacteria and yeasts. The lowest MIC (16 µg ml-1) of AgNPs was found against P. aeruginosa, followed by C. albicans and M. furfur (both 32 µg ml-1), B. subtilis and E. coli (both 64 µg ml-1), and then S. aureus and Klebsiella pneumoniae (256 µg ml-1). The high synergistic effect of antibiotics in combination with AgNPs against tested strains was found. The in vitro cytotoxicity of AgNPs against mouse fibroblasts and cancer HeLa cell lines revealed a dose dependent potential. The IC50 value of AgNPs was found in concentrations of 4 and 3.8 µg ml-1, respectively. Combination of AgNPs and antibiotics significantly decreased concentrations of both antimicrobials used and retained their high antibacterial and antifungal activity. The synthesis of AgNPs using S. xinghaiensis OF1 strain is an eco-friendly, cheap and nontoxic method. The antimicrobial activity of AgNPs could result from their small size. Remarkable synergistic effect of antibiotics and AgNPs offer their valuable potential in nanomedicine for clinical application as a combined therapy in the future.


Assuntos
Anti-Infecciosos/química , Anti-Infecciosos/metabolismo , Anti-Infecciosos/farmacologia , Nanopartículas Metálicas/química , Prata/química , Streptomyces/metabolismo , Animais , Antibacterianos/farmacologia , Antifúngicos/farmacologia , Bacillus subtilis/efeitos dos fármacos , Candida albicans/citologia , Candida albicans/efeitos dos fármacos , Sinergismo Farmacológico , Escherichia coli/citologia , Escherichia coli/efeitos dos fármacos , Fibroblastos/efeitos dos fármacos , Células HeLa/efeitos dos fármacos , Humanos , Índia , Klebsiella pneumoniae/efeitos dos fármacos , Camundongos , Testes de Sensibilidade Microbiana , Microscopia Eletrônica de Transmissão , Pseudomonas aeruginosa/efeitos dos fármacos , Espectroscopia de Infravermelho com Transformada de Fourier , Staphylococcus aureus/citologia , Staphylococcus aureus/efeitos dos fármacos , Streptomyces/isolamento & purificação
8.
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
9.
J Basic Microbiol ; 57(9): 793-800, 2017 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-28670763

RESUMO

In this study, we present the in vitro antifungal activity of silver nanoparticles (AgNPs) synthesized from acidophilic actinobacterium Pilimelia columellifera subsp. pallida SL19 strain, alone and in combination with antibiotics viz., amphotericin B, fluconazole, and ketoconazole against pathogenic fungi, namely Candida albicans, Malassezia furfur, and Trichophyton erinacei. The minimum inhibitory concentration (MIC) and minimum biocidal concentration (MBC) of AgNPs against test fungi were evaluated. The fractional inhibitory concentration (FIC) index was determined to estimate antifungal activity of AgNPs combined with antibiotics. Antifungal activity of AgNPs varied among the tested fungal strains. M. furfur was found to be most sensitive to biogenic silver nanoparticles, followed by C. albicans and T. erinacei. The lowest MIC of AgNPs was noticed against M. furfur (16 µg ml-1 ). Synergistic effect was observed on C. albicans when AgNP were combined with amphotericin B and ketoconazole and on M. furfur with fluconazole and ketoconazole (FIC index of 0.5). Cytotoxic effect of AgNPs on HeLa and 3T3 cell lines was evaluated. The IC50 values were found to be 55 and 25 µg ml-1 , respectively. The present study indicates that silver nanoparticles from P. columellifera subsp. pallida SL19 strain have antifungal activity, both alone and in combination with antibiotics, and offer a valuable contribution to nanomedicine.


Assuntos
Actinobacteria/química , Antifúngicos/farmacologia , Fungos/efeitos dos fármacos , Nanopartículas Metálicas/química , Prata/farmacologia , Células 3T3 , Actinobacteria/metabolismo , Anfotericina B/farmacologia , Animais , Antibacterianos/farmacologia , Candida albicans/efeitos dos fármacos , Candida albicans/patogenicidade , Fungos/patogenicidade , Células HeLa , Humanos , Cetoconazol/farmacologia , Camundongos , Testes de Sensibilidade Microbiana , Micoses/microbiologia
10.
IET Nanobiotechnol ; 11(3): 336-342, 2017 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-28476992

RESUMO

In this study, silver nanoparticles (AgNPs) were biosynthesised by using acidophilic actinobacterial SH11 strain isolated from pine forest soil. Isolate SH11 was identified based on 16S rRNA gene sequence to Streptomyces kasugaensis M338-M1T and S. celluloflavus NRRL B-2493T (99.8% similarity, both). Biosynthesised AgNPs were analysed by UV-visible spectroscopy, which revealed specific peak at λ = 420 nm. Transmission electron microscopy analyses showed polydispersed, spherical nanoparticles with a mean size of 13.2 nm, while Fourier transform infrared spectroscopy confirmed the presence of proteins as the capping agents over the surface of AgNPs. The zeta potential was found to be -16.6 mV, which indicated stability of AgNPs. The antibacterial activity of AgNPs from SH11 strain against gram-positive (Staphylococcus aureus and Bacillus subtilis) and gram-negative (Escherichia coli) bacteria was estimated using disc diffusion, minimum inhibitory concentration and live/dead analyses. The AgNPs showed the maximum antimicrobial activity against E. coli, followed by B. subtilis and S. aureus. Further, the synergistic effect of AgNPs in combination with commercial antibiotics (kanamycin, ampicillin, tetracycline) was also evaluated against bacterial isolates. The antimicrobial efficacy of antibiotics was found to be enhanced in the presence of AgNPs.


Assuntos
Actinobacteria/metabolismo , Antibacterianos/administração & dosagem , Fenômenos Fisiológicos Bacterianos/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Nanopartículas Metálicas/administração & dosagem , Prata/administração & dosagem , Actinobacteria/classificação , Antibacterianos/química , Sobrevivência Celular/fisiologia , Relação Dose-Resposta a Droga , Teste de Materiais , Nanopartículas Metálicas/química , Nanopartículas Metálicas/ultraestrutura , Tamanho da Partícula , Prata/química , Especificidade da Espécie , Resultado do Tratamento
11.
Crit Rev Biotechnol ; 37(6): 765-778, 2017 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-27748137

RESUMO

Mycoendophytes are the fungi that occur inside the plant tissues without exerting any negative impact on the host plant. They are most frequently isolated endophytes from the leaf, stem, and root tissues of various plants. Among all fungi, the mycoendophytes as biosynthesizer of noble metal nanoparticles (NPs) are less known. However, some reports showing efficient synthesis of metal nanoparticles, mainly silver nanoparticles and its remarkable antimicrobial activity against bacterial and fungal pathogens of humans and plants. The nanoparticles synthesized from mycoendophytes present stability, polydispersity, and biocompatibility. These are non-toxic to humans and environment, can be gained in an easy and cost-effective manner, have wide applicability and could be explored as promising candidates for a variety of biomedical, pharmaceutical, and agricultural applications. Mycogenic silver nanoparticles have also demonstrated cytotoxic activity against cancer cell lines and may prove to be a promising anticancer agent. The present review focuses on the biological synthesis of metal nanoparticles from mycoendophytes and their application in medicine. In addition, different mechanisms of biosynthesis and activity of nanoparticles on microbial cells, as well as toxicity of these mycogenic metal nanoparticles, have also been discussed.


Assuntos
Nanopartículas Metálicas , Endófitos , Fungos , Humanos , Plantas , Prata
12.
Antonie Van Leeuwenhoek ; 109(12): 1583-1591, 2016 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-27558132

RESUMO

Two acidophilic actinobacteria, isolates NA14 and NF37T, were the subject of a polyphasic taxonomic study. Chemotaxonomic and morphological properties of the isolates were characteristic of the genus Streptacidiphilus. The isolates were shown to have identical 16S rRNA gene sequences and to be closely related to Streptacidiphilus neutrinimicus DSM 41755T (>99.9 %). However, DNA:DNA relatedness between isolate NF37T and the type strain of S. neutrinimicus was found to be low at 11.1 (±3.5) %. A broad range of phenotypic features were shown to distinguish the isolates from their close phylogenetic neighbours. These data shown that the isolates form a novel species of Streptacidiphilus for which the name Streptacidiphilus toruniensis sp. nov. is proposed. The type strain is NF37T (= DSM 102291T = NCIMB 15025T).


Assuntos
Actinobacteria/isolamento & purificação , Florestas , Pinus , Microbiologia do Solo , Actinobacteria/classificação , DNA Bacteriano , Tipagem Molecular , Filogenia , RNA Bacteriano , RNA Ribossômico 16S/genética
13.
Med Microbiol Immunol ; 205(5): 435-47, 2016 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-27278909

RESUMO

The authors report the biological synthesis of silver nanoparticles (AgNPs) by alkaliphilic actinobacterium Nocardiopsis valliformis OT1 strain isolated for the first time from Lonar crater, India. The primary detection of silver NPs formation was made by colour change from colourless to dark brown and confirmed by UV-Vis spectrum of AgNPs at 423 nm, specific for AgNPs. Further, AgNPs were characterized by nanoparticle tracking analysis, Zeta sizer, Fourier transform infrared spectroscopy (FTIR) and transmission electron microscopy (TEM) analyses. FTIR analysis showed the presence of proteins as capping agent. TEM analysis revealed the formation of spherical and polydispersed AgNPs within the size range of 5-50 nm. The antimicrobial activity of silver nanoparticles against Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, Staphylococcus aureus and Bacillus subtilis was evaluated. The AgNPs showed the maximum antibacterial activity against B. subtilis (Gram positive) and the minimum against E. coli (Gram negative). The minimal inhibitory concentration values of AgNPs for the tested bacteria were found to be in the range of 30-80 µg/mL. The AgNPs demonstrated higher antibacterial activity against all the bacteria tested as compared with the commercially available antibiotics. The cytotoxicity of biosynthesized AgNPs against in vitro human cervical cancer cell line (HeLa) demonstrated a dose-response activity. The IC50 value was found to be 100 µg/mL of AgNPs against cancer HeLa cell line.


Assuntos
Actinobacteria/isolamento & purificação , Actinobacteria/metabolismo , Antibacterianos/metabolismo , Antineoplásicos/farmacologia , Nanopartículas/metabolismo , Prata/metabolismo , Animais , Sobrevivência Celular/efeitos dos fármacos , Microbiologia Ambiental , Células Epiteliais/efeitos dos fármacos , Células Epiteliais/fisiologia , Bactérias Gram-Negativas/efeitos dos fármacos , Bactérias Gram-Positivas/efeitos dos fármacos , Células HeLa , Humanos , Índia , Concentração Inibidora 50 , Testes de Sensibilidade Microbiana , Microscopia Eletrônica de Transmissão , Nanopartículas/ultraestrutura , Espectrofotometria , Espectroscopia de Infravermelho com Transformada de Fourier
14.
J Basic Microbiol ; 56(5): 541-56, 2016 May.
Artigo em Inglês | MEDLINE | ID: mdl-27151174

RESUMO

Biosynthesis of silver nanoparticles (AgNPs) is an eco-friendly approach by using different biological sources; for example, plants and microorganisms such as bacteria, fungi, and actinobacteria. In this report, we present the biological synthesis of silver nanoparticles (AgNPs) by acidophilic actinomycetes SL19 and SL24 strains isolated from pine forest soil (pH < 4.0). The isolates based on 16S rRNA gene sequence were identified as Pilimelia columellifera subsp. pallida. The synthesized AgNPs were characterized by visual observations of colour change from light-yellow to dark-brown. The UV-vis spectra of AgNPs were recorded at 425 and 430 nm. The AgNPs were further characterized by Nanoparticle tracking analysis (NTA), Zeta potential, Fourier transform infrared spectroscopy (FTIR) and Transmission electron microscopy (TEM). FTIR analysis revealed the presence of proteins as a capping agent. TEM analysis confirmed the formation of spherical and polydispersed NPs of 12.7 and 15.9 nm sizes. The in vitro antibacterial activity of AgNPs alone and in combination with antibiotics was evaluated against clinical bacteria viz., Staphylococcus aureus, Bacillus subtilis, Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, and uropathogens such as Enterobacter, S. aureus, P. aeruginosa, K. pneumoniae, and E. coli. The lowest MIC (40 µg ml(-1) ) was demonstrated by AgNPs synthesized from SL24 against E. coli. However, the AgNPs of SL19 showed lowest MIC (70 µg ml(-1) ) against S. aureus. The activity of antibiotic was enhanced, when tested in combination with silver nanoparticles synthesized from both actinobacterial strains.


Assuntos
Antibacterianos/farmacologia , Bactérias/efeitos dos fármacos , Nanopartículas Metálicas , Micromonosporaceae/metabolismo , Prata/farmacologia , Antibacterianos/biossíntese , Bacillus subtilis/efeitos dos fármacos , Escherichia coli/efeitos dos fármacos , Klebsiella pneumoniae/efeitos dos fármacos , Testes de Sensibilidade Microbiana , Micromonosporaceae/isolamento & purificação , Microscopia Eletrônica de Transmissão , Pseudomonas aeruginosa/efeitos dos fármacos , RNA Ribossômico 16S/genética , Microbiologia do Solo , Staphylococcus aureus/efeitos dos fármacos
15.
Antonie Van Leeuwenhoek ; 108(2): 435-42, 2015 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-26026797

RESUMO

Seven acidophilic actinobacteria isolated from humus and mineral layers of a spruce forest soil were examined using a polyphasic approach. Chemotaxonomic properties of the isolates were found to be consistent with their classification in the genus Actinospica. The strains formed a distinct phyletic line in the Actinospica 16S rRNA gene tree being most closely related to Actinospica robiniae DSM 44927(T) (98.7-99.3 % similarity). DNA:DNA relatedness between isolate CSCA57(T) and the type strain of A. robiniae was found to be low at 40.8 (±6.6) %. The isolates were shown to have many phenotypic properties in common and were distinguished readily from the type strains of Actinospica acidiphila and A. robiniae using a range of phenotypic features. On the basis of these data the seven isolates were considered to represent a new species for which the name Actinospica durhamensis sp. nov. is proposed. The type strain of the species is CSCA 57(T) (=DSM 46820(T) = NCIMB 14953(T)).


Assuntos
Actinobacteria/classificação , Actinobacteria/isolamento & purificação , Microbiologia do Solo , Actinobacteria/genética , Actinobacteria/fisiologia , Técnicas de Tipagem Bacteriana , Análise por Conglomerados , Meios de Cultura/química , DNA Bacteriano/química , DNA Bacteriano/genética , DNA Ribossômico/química , DNA Ribossômico/genética , Florestas , Concentração de Íons de Hidrogênio , Dados de Sequência Molecular , Hibridização de Ácido Nucleico , Filogenia , Picea , RNA Ribossômico 16S/genética , Análise de Sequência de DNA
16.
Antonie Van Leeuwenhoek ; 108(2): 267-89, 2015 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-26093915

RESUMO

Endophytes are the microorganisms that exist inside the plant tissues without having any negative impact on the host plant. Medicinal plants constitute the huge diversity of endophytic actinobacteria of economical importance. These microbes have huge potential to synthesis of numerous novel compounds that can be exploited in pharmaceutical, agricultural and other industries. It is of prime importance to focus the present research on practical utilization of this microbial group in order to find out the solutions to the problems related to health, environment and agriculture. An extensive characterization of diverse population of endophytic actinobacteria associated with medicinal plants can provide a greater insight into the plant-endophyte interactions and evolution of mutualism. In the present review, we have discussed the diversity of endophytic actinobacteria of from medicinal plants their multiple bioactivities.


Assuntos
Actinobacteria/isolamento & purificação , Endófitos/classificação , Endófitos/isolamento & purificação , Plantas Medicinais/microbiologia , Actinobacteria/classificação , Actinobacteria/fisiologia , Biodiversidade , Endófitos/fisiologia , Simbiose
17.
Appl Microbiol Biotechnol ; 98(19): 8083-97, 2014 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-25158833

RESUMO

Biogenic synthesis of metal nanoparticles has been well proved by using bacteria, fungi, algae, actinomycetes, plants, etc. Among the different microorganisms used for the synthesis of metal nanoparticles, actinomycetes are less known. Although, there are reports, which have shown that actinomycetes are efficient candidates for the production of metal nanoparticles both intracellularly and extracellularly. The nanoparticles synthesized by the members of actinomycetes present good polydispersity and stability and possess significant biocidal activities against various pathogens. The present review focuses on biological synthesis of metal nanoparticles and their application in medicine. In addition, the toxicity of these biogenic metal nanoparticles to human beings and environment has also been discussed.


Assuntos
Actinobacteria/metabolismo , Microbiologia Industrial , Nanopartículas Metálicas/análise , Nanopartículas Metálicas/toxicidade
18.
Antonie Van Leeuwenhoek ; 104(6): 965-72, 2013 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-23989983

RESUMO

Three acidophilic actinobacteria, isolates LSCA2, FGG8 and HSCA14(T), recovered from spruce litter were examined using a polyphasic approach. Chemotaxonomic and morphological properties of the isolates were found to be consistent with their classification in the genus Streptacidiphilus. The isolates were shown to have identical 16S rRNA gene sequences and were most closely related to Streptacidiphilus neutrinimicus DSM 41755(T) (99.9 % similarity). However, DNA:DNA relatedness between isolate HSCA14(T) and the type strain of S. neutrinimicus was found to be low at 44.0 (±14.1) %. A combination of phenotypic features, including degradative and nutritional characteristics were shown to distinguish the isolates from their nearest phylogenetic neighbours. Data from this study show that the isolates form a novel species in the genus for which the name S. hamsterleyensis sp. nov. is proposed. The type strain is HSCA 14(T) (=DSM 45900(T) = KACC 17456(T) = NCIMB 14865(T)).


Assuntos
Microbiologia do Solo , Streptomycetaceae/classificação , Streptomycetaceae/isolamento & purificação , Técnicas de Tipagem Bacteriana , Análise por Conglomerados , DNA Bacteriano/química , DNA Bacteriano/genética , DNA Ribossômico/química , DNA Ribossômico/genética , Dados de Sequência Molecular , Hibridização de Ácido Nucleico , Filogenia , RNA Ribossômico 16S/genética , Análise de Sequência de DNA , Streptomycetaceae/genética , Árvores
19.
Antonie Van Leeuwenhoek ; 104(2): 199-206, 2013 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-23716127

RESUMO

The taxonomic position of three acidophilic actinobacteria, strains FGG38, FGG39 and FSCA67(T), isolated from the fermentation litter layer of a spruce forest soil was established using a polyphasic approach. The strains were shown to have chemotaxonomic and morphological properties consistent with their classification in the genus Streptacidiphilus and formed a distinct phyletic line in the Streptacidiphilus 16S rRNA gene tree being most closely related to Streptacidiphilus albus DSM 41753(T) (99.4 % similarity). DNA:DNA relatedness data showed that isolate FSCA67(T) and the type strain of S. albus belonged to markedly distinct genomic species. The isolates had many phenotypic properties in common and were distinguished readily from their closest phylogenetic neighbours in the Streptacidiphilus gene tree using a broad range of these features. Based on the combined genotypic and phenotypic data the three isolates are considered to represent a new Streptacidiphilus species. The name Streptacidiphilus durhamensis sp. nov. is proposed for this taxon with isolate FSCA67(T) (=DSM 45796(T) = KACC 17154(T) = NCIMB 14828(T)) [corrected] as the type strain.


Assuntos
Picea , Microbiologia do Solo , Streptomycetaceae , Técnicas de Tipagem Bacteriana , DNA Bacteriano/genética , Genótipo , Filogenia , RNA Ribossômico 16S/genética , Streptomycetaceae/classificação , Streptomycetaceae/genética , Streptomycetaceae/isolamento & purificação
20.
Antonie Van Leeuwenhoek ; 103(5): 1079-88, 2013 May.
Artigo em Inglês | MEDLINE | ID: mdl-23371034

RESUMO

Actinomycetes growing on acidified starch-casein agar seeded with suspensions of litter and mineral soil from a spruce forest were provisionally assigned to the genus Nocardia based upon colonial properties. Representative isolates were found to grow optimally at pH 5.5, have chemotaxonomic and morphological features consistent with their assignment to the genus Nocardia and formed two closely related subclades in the Nocardia 16S rRNA gene tree. DNA:DNA relatedness assays showed that representatives of the subclades belong to a single genomic species. The isolates were distantly associated with their nearest phylogenetic neighbour, the type strain of Nocardia kruczakiae, and were distinguished readily from the latter based on phenotypic properties. On the basis of these data it is proposed that the isolates merit recognition as a new species, Nocardia aciditolerans sp. nov. The type strain is isolate CSCA68(T) (=KACC 17155(T) = NCIMB 14829(T) = DSM 45801(T)).


Assuntos
Nocardia/classificação , Nocardia/isolamento & purificação , Microbiologia do Solo , Técnicas de Tipagem Bacteriana , Análise por Conglomerados , Meios de Cultura/química , DNA Bacteriano/química , DNA Bacteriano/genética , DNA Ribossômico/química , DNA Ribossômico/genética , Concentração de Íons de Hidrogênio , Dados de Sequência Molecular , Nocardia/genética , Nocardia/fisiologia , Hibridização de Ácido Nucleico , Filogenia , Picea/crescimento & desenvolvimento , RNA Ribossômico 16S/genética , Análise de Sequência de DNA , Árvores
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