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1.
Neetu Israni Surabhi Thapa Srividya Shivakumar 《Journal of Genetic Engineering and Biotechnology》2018,16(2):265-271
The applicability of Streptomyces sp. cell lytic enzymes for devising a simple and competent biological polyhydroxyalkanoate (PHA) recovery approach from Bacillus megaterium cells was investigated. B. megaterium strain Ti3 produced 50% (w/w) PHA using glucose as carbon source. The intracellular PHA was recovered employing a non-PHA accumulating actinomycetes (Tia1) identified as Streptomyces albus, having potent lytic activity against living and heat inactivated B. megaterium. Interestingly, maximum biomass (2.53?±?0.6?g/L by 24?h) of the lytic actinomycete was obtained in PHA production medium itself thus circumventing the prior actinomycete acclimatization just by co-inoculation with B. megaterium as an inducer. Maximum lytic activity was observed at pH 6.0, 40?°C, 220?mg of biomass and 33.3?mL of concentrated culture filtrate in a 100?mL reaction mixture. Preliminary biochemical investigations confirmed the proteolytic and caseinolytic nature of the lytic enzyme. PHA yield of 0.55?g/g by co-inoculation extraction approach was comparable with the conventional sodium hypochlorite based extraction method. Interestingly, S. albus also demonstrated a broad spectrum lytic potential against varied Gram-negative and Gram-positive PHA producers highlighting the extensive applicability of this biolytic PHA recovery approach. The lytic enzyme retained almost 100% relative activity on storage at ?20?°C upto two months. 1H Nuclear magnetic resonance analysis of the extracted polymer confirmed it as a homopolymer composed of 3-hydroxybutyrate monomeric units. This is the first report on Streptomyces sp. based biological and eco-friendly, intracellular PHA recovery from Bacillus spp. 相似文献
2.
Jeny Adina Larrea-Murrell Marcia Maria Rojas-Badia Ivette García-Soto Beatriz Romeu-Alvarez Tristano Bacchetti Annika Gillis Ana Karina Boltes-Espinola Mayra Heydrich-Perez Daysi Lugo-Moya Jacques Mahillon 《World journal of microbiology & biotechnology》2018,34(2):28
Genotypic and phenotypic characterization of Bacillus spp. from polluted freshwater has been poorly addressed. The objective of this research was to determine the diversity and enzymatic potentialities of Bacillus spp. strains isolated from the Almendares River. Bacilli strains from a polluted river were characterized by considering the production of extracellular enzymes using API ZYM. 14 strains were selected and identified using 16S rRNA, gyrB and aroE genes. Genotypic diversity of the Bacillus spp. strains was evaluated using pulsed field gel electrophoresis. Furthermore, the presence of genetic determinants of potential virulence toxins of the Bacillus cereus group and proteinaceous crystal inclusions of Bacillus thuringiensis was determined. 10 strains were identified as B. thuringiensis, two as Bacillus megaterium, one as Bacillus pumilus and one as Bacillus subtilis. Most strains produced proteases, amylases, phosphatases, esterases, aminopeptidases and glucanases, which reflect the abundance of biopolymeric matter in Almendares River. Comparison of the typing results revealed a spatio-temporal distribution among B. thuringiensis strains along the river. The results of the present study highlight the genotypic and phenotypic diversity of Bacillus spp. strains from a polluted river, which contributes to the knowledge of genetic diversity of Bacilli from tropical polluted freshwater ecosystems. 相似文献
3.
Isolation from haddock tissue of psychrophilic bacteria with maximum growth temperature below 20 degrees C. 总被引:1,自引:1,他引:0
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Protoplast fusion was investigated as a technique for genetically manipulating two lignin-degrading Streptomyces strains, Streptomyces viridosporus T7A and Streptomyces setonii 75Vi2. Four of 19 recombinants tested showed enhanced production of acid-precipitable polymeric lignin (APPL), producing 155 to 264% more APPL from corn stover lignocellulose than was produced by the wild-type S. viridosporus T7A. APPLs are lignin degradation intermediates known to be potentially valuable chemical products produced by bioconversion of lignin with Streptomyces spp. The prospects of utilizing protoplast fusion to construct APPL-overproducing Streptomyces strains was considered especially promising. 相似文献
4.
Ryan F. Seipke 《PloS one》2015,10(1)
Streptomyces spp. are robust producers of medicinally-, industrially- and agriculturally-important small molecules. Increased resistance to antibacterial agents and the lack of new antibiotics in the pipeline have led to a renaissance in natural product discovery. This endeavor has benefited from inexpensive high quality DNA sequencing technology, which has generated more than 140 genome sequences for taxonomic type strains and environmental Streptomyces spp. isolates. Many of the sequenced streptomycetes belong to the same species. For instance, Streptomyces albus has been isolated from diverse environmental niches and seven strains have been sequenced, consequently this species has been sequenced more than any other streptomycete, allowing valuable analyses of strain-level diversity in secondary metabolism. Bioinformatics analyses identified a total of 48 unique biosynthetic gene clusters harboured by Streptomyces albus strains. Eighteen of these gene clusters specify the core secondary metabolome of the species. Fourteen of the gene clusters are contained by one or more strain and are considered auxiliary, while 16 of the gene clusters encode the production of putative strain-specific secondary metabolites. Analysis of Streptomyces albus strains suggests that each strain of a Streptomyces species likely harbours at least one strain-specific biosynthetic gene cluster. Importantly, this implies that deep sequencing of a species will not exhaust gene cluster diversity and will continue to yield novelty. 相似文献
5.
Atsushi Kakinuma Yoshio Nakao Seizi Igarasi Koichi Ogata 《Bioscience, biotechnology, and biochemistry》2013,77(5):300-306
Seven strains of microorganisms selected by the previous screening tests were further compared on their ability to produce extracellular enzyme systems capable of degrading RNA into 5′-ribonucleotides. As a result, two strains of Streptomyces were finally concluded to be most preferable. When these two were applied, the rate of 5′-nucleotide production reached up to 70%.Bacillus subtilis was outstanding in its activity to degrade RNA, but its PDase activity producing 5′-nucleotides from RNA was found to be lower than those of Streptomyces strains. A pathway involving 3′- and 5′-nucleotides as intermediates was proposed for the degradation of RNA by the Bacillus enzyme system. The activity of RNA-degrading enzyme system of Bacillus subtilis contained in the supernatant of culture fluid was found to be lost at 700°C but remained to certain extent at 100°C, a possible mechanism for the phenomenon being discussed. Usability of the Bacillus enzyme system in the practical production of 5′-nucleotides under the condition of high RNA concentration was discussed. 相似文献
6.
《Systematic and applied microbiology》2021,44(5):126244
Marine sponges represent a rich source of uncharacterized microbial diversity, and many are host to microorganisms that produce biologically active specialized metabolites. Here, a polyphasic approach was used to characterize two Actinobacteria strains, P01-B04T and P01-F02, that were isolated from the marine sponges Geodia barretti (Bowerbank, 1858) and Antho dichotoma (Esper, 1794), respectively. Phylogenetic analysis based on 16S rRNA gene sequences indicated that strains P01-B04T and P01-F02 are closely related to Streptomyces beijiangensis DSM 41794T, Streptomyces laculatispora NRRL B-24909T, and Streptomyces brevispora NRRL B-24910T. The two strains showed nearly identical 16S rRNA gene sequences (99.93%), and the average nucleotide identity (ANI) and digital DNA-DNA hybridization (dDDH) relatedness values were 99.96% and 99.6%, respectively, suggesting that these strains are affiliated with the same species. Chemotaxonomic and culture characteristics of both strains were also consistent with the genus Streptomyces, while phenotypic properties, genome-based comparisons, and phylogenomic analyses distinguished strains P01-B04T and P01-F02 from their closest phylogenetic relatives. In silico analysis predicted that the 8.9 Mb genome of P01-B04T contains at least 41 biosynthetic gene clusters (BGCs) encoding secondary metabolites, indicating that this strain could express diverse bioactive metabolites; in support of this prediction, this strain expressed antibacterial activity against Gram-positive bacteria including a clinical isolate of methicillin-resistant Staphylococcus aureus (MRSA) EAMC30. Based on these results, the marine sponge-associated isolates represent a novel species of the genus Streptomyces, for which the name Streptomyces poriferorum sp. nov. is proposed, with P01-B04T (=DSM 111306T = CCM 9048T) as the type strain. 相似文献
7.
Bacillus Endospores Isolated from Granite: Close Molecular Relationships to Globally Distributed Bacillus spp. from Endolithic and Extreme Environments 总被引:1,自引:0,他引:1
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As part of an ongoing effort to catalog spore-forming bacterial populations in environments conducive to interplanetary transfer by natural impacts or by human spaceflight activities, spores of Bacillus spp. were isolated and characterized from the interior of near-subsurface granite rock collected from the Santa Catalina Mountains, AZ. Granite was found to contain ~500 cultivable Bacillus spores and ~104 total cultivable bacteria per gram. Many of the Bacillus isolates produced a previously unreported diffusible blue fluorescent compound. Two strains of eight tested exhibited increased spore UV resistance relative to a standard Bacillus subtilis UV biodosimetry strain. Fifty-six isolates were identified by repetitive extragenic palindromic PCR (rep-PCR) and 16S rRNA gene analysis as most closely related to B. megaterium (15 isolates), B. simplex (23 isolates), B. drentensis (6 isolates), B. niacini (7 isolates), and, likely, a new species related to B. barbaricus (5 isolates). Granite isolates were very closely related to a limited number of Bacillus spp. previously found to inhabit (i) globally distributed endolithic sites such as biodeteriorated murals, stone tombs, underground caverns, and rock concretions and (ii) extreme environments such as Antarctic soils, deep sea floor sediments, and spacecraft assembly facilities. Thus, it appears that the occurrence of Bacillus spp. in endolithic or extreme environments is not accidental but that these environments create unique niches excluding most Bacillus spp. but to which a limited number of Bacillus spp. are specifically adapted. 相似文献
8.
Thirteen different chitin-degrading bacteria were isolated from soil and sediment samples. Five of these strains (SGE2, SGE4, SSL3, MG1, and MG3) exhibited antifungal activity against phytopathogenic fungi. Analyses of the 16S rRNA genes and the substrate spectra revealed that the isolates belong to the genera Bacillus or Streptomyces. The closest relatives were Bacillus chitinolyticus (SGE2, SGE4, and SSL3), B. ehimensis (MG1), and Streptomyces griseus (MG3). The chitinases present in the culture supernatants of the five isolates revealed optimal activity between 45°C and 50°C and at pH values of 4 (SSL3), 5 (SGE2 and MG1), 6 (SGE4), and 5–7 (MG3). The crude chitinase preparations of all five strains possessed antifungal activity. The chitinase of MG3 (ChiIS) was studied further, since the crude enzyme conferred strong growth suppression of all fungi tested and was very active over the entire pH range tested. The chiIS gene was cloned and the gene product was purified. The deduced protein consisted of 303 amino acids with a predicted molecular mass of 31,836 Da. Sequence analysis revealed that ChiIS of MG3 is similar to chitinases of Streptomyces species, which belong to family 19 of glycosyl hydrolases. Purified ChiIS showed remarkable antifungal activity and stability. 相似文献
9.
Sonali Ghosh George Korza Mark Maciejewski Peter Setlow 《Journal of bacteriology》2015,197(5):992-1001
This work was undertaken to obtain information on levels of metabolism in dormant spores of Bacillus species incubated for weeks at physiological temperatures. Spores of Bacillus megaterium and Bacillus subtilis strains were harvested shortly after release from sporangia and incubated under various conditions, and dormant spore metabolism was monitored by 31P nuclear magnetic resonance (NMR) analysis of molecules including 3-phosphoglyceric acid (3PGA) and ribonucleotides. Incubation for up to 30 days at 4, 37, or 50°C in water, at 37 or 50°C in buffer to raise the spore core pH from ∼ 6.3 to 7.8, or at 4°C in spent sporulation medium caused no significant changes in ribonucleotide or 3PGA levels. Stage I germinated spores of Bacillus megaterium that had slightly increased core water content and a core pH of 7.8 also did not degrade 3PGA and accumulated no ribonucleotides, including ATP, during incubation for 8 days at 37°C in buffered saline. In contrast, spores incubated for up to 30 days at 37 or 50°C in spent sporulation medium degraded significant amounts of 3PGA and accumulated ribonucleotides, indicative of RNA degradation, and these processes were increased in B. megaterium spores with a core pH of ∼7.8. However, no ATP was accumulated in these spores. These data indicate that spores of Bacillus species stored in water or buffer at low or high temperatures exhibited minimal, if any, metabolism of endogenous compounds, even when the spore core pH was 7.8 and core water content was increased somewhat. However, there was some metabolism in spores stored in spent sporulation medium. 相似文献
10.
Environments co-contaminated with metals and organic compounds are difficult to remediate. Actinobacteria is an important group of microorganisms found in soils, with high metabolic versatility and potential for bioremediation. In this paper, actinobacteria were used to remediate soil co-contaminated with Cr(VI) and lindane. Five actinobacteria, tolerant to Cr(VI) and lindane mixture were selected: Streptomyces spp. A5, A11, M7, and MC1, and Amycolatopsis tucumanensis DSM 45259. Sterilized soil samples were inoculated with actinobacteria strains, either individually or as a consortium, and contaminated with Cr(VI) and lindane, either immediately or after 7 days of growth, and incubated at 30 °C during 14 days. All actinobacteria were able to grow and remove both contaminants, the consortium formed by Streptomyces spp. A5, M7, MC1, and A. tucumanensis showed the highest Cr(VI) removal, while Streptomyces sp. M7 produced the maximum lindane removal. In non-sterile soil samples, Streptomyces sp. M7 and the consortium removed more than 40% of the lindane, while Streptomyces sp. M7 demonstrated the greatest Cr(VI) removal. The most appropriate strategy for bioremediation of Cr(VI) and lindane co-contaminated soils would be the inoculation with Streptomyces sp. M7. 相似文献
11.
《Journal of Fermentation Technology》1988,66(5):585-589
The production of inosine by microbial conversion of 5′-inosinic acid (IMP) was investigated. Among the various strains of Streptomyces and Bacillus tested, Streptomyces aureus NCIB 9803 was selected for the microbial conversion process due to its high IMP-degrading activity. A maximum conversion yield of 0.43 (86% of the theoretical value) was obtained when IMP was added to the culture medium at 24 h. Kinetic studies with [8-14C] IMP showed that the difference from the theoretical values mainly attributable to the uptake of inosine by S. aureus. 相似文献
12.
《Systematic and applied microbiology》2019,42(3):360-372
The species Bacillus badius is one of the oldest members of the genus Bacillus isolated from faeces of children and was classified based on its ability to form endospores [8]. In 16S rRNA gene sequence and phylogenetic analysis, Bacillus badius DSM 23T shared low similarity (93.0%) and distant relationship with B. subtilis, the type species of the genus Bacillus indicating that it does not belong to this genus. Additional strains of the species, B. badius DSM 5610, DSM 30822 and B. encimensis SGD-V-25 (which has been recently reclassified as a member of this species) were included in the study to consider intraspecies diversity. Detailed molecular phylogenetic and comparative genome analysis clearly showed that the strains of B. badius were consistently retrieved outside the cluster of Bacillus sensu stricto and also distantly related to the genera Domibacillus and Quasibacillus. Further, the data from biochemical reactions (inability to ferment most carbohydrates), polar lipids profile (presence of diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine and an aminophosphoglycolipid) and fatty acids supported the molecular analysis. Thus the four B. badius strains; DSM 23T, DSM 5610, DSM 30822 and SGD-V-25 displayed sufficient demarcating phenotypic characteristics that warrant their classification as members of a novel genus and single species, for which the name Pseudobacillus badius gen. nov. comb. nov. is proposed with Pseudobacillus badius DSM 23T (= ATCC 14574T) as the type strain. Additionally, based on our findings from phenotypic, chemotaxonomic and genotypic parameters, Bacillus wudalianchiensis DSM 100757T was reclassified as Pseudobacillus wudalianchiensis comb. nov. 相似文献
13.
Alfredo F. Braña Miriam Rodríguez Pallab Pahari Jurgen Rohr Luis A. García Gloria Blanco 《Archives of microbiology》2014,196(5):345-355
Activation and silencing of antibiotic production was achieved in Streptomyces albus J1074 and Streptomyces lividans TK21 after introduction of genes within the thienamycin cluster from S. cattleya. Dramatic phenotypic and metabolic changes, involving activation of multiple silent secondary metabolites and silencing of others normally produced, were found in recombinant strains harbouring the thienamycin cluster in comparison to the parental strains. In S. albus, ultra-performance liquid chromatography purification and NMR structural elucidation revealed the identity of four structurally related activated compounds: the antibiotics paulomycins A, B and the paulomenols A and B. Four volatile compounds whose biosynthesis was switched off were identified by gas chromatography–mass spectrometry analyses and databases comparison as pyrazines; including tetramethylpyrazine, a compound with important clinical applications to our knowledge never reported to be produced by Streptomyces. In addition, this work revealed the potential of S. albus to produce many others secondary metabolites normally obtained from plants, including compounds of medical relevance as dihydro-β-agarofuran and of interest in perfume industry as β-patchoulene, suggesting that it might be an alternative model for their industrial production. In S. lividans, actinorhodins production was strongly activated in the recombinant strains whereas undecylprodigiosins were significantly reduced. Activation of cryptic metabolites in Streptomyces species might represent an alternative approach for pharmaceutical drug discovery. 相似文献
14.
The leaves of Dilobeia thouarsii (Roemer and Schulte), a tree that is endemic to Madagascar (Proteaceae), are used in traditional Malagasy medicine to treat bacterial skin infections and wounds. This study investigated the in vitro antibacterial activities of D. thouarsii leaf extracts and identified the bioactive compounds with the aim of providing a scientific basis for its use against skin diseases. Using broth microdilution method for leaf crude extract and its compounds, we investigated inhibition of the growth of Bacillus cereus, Bacillus megaterium, Staphylococcus aureus, Enterococcus faecalis, Vibrio harveyi, Vibrio fisheri, Salmonella Typhimurium, Salmonella antarctica, Escherichia coli, and Klebsiella pneumoniae. The two purified phenolic compounds from leaf ethyl acetate extracts (1, 2) were found to be more active than the crude extract itself. The structure of the two compounds was elucidated by NMR and mass spectrometry: compound 1 was identified as 4-aminophenol and compound 2 as 4-hydroxybenzaldehyde. A marked inhibitory effect (MIC < 0.1 mg/ml) was found against S. aureus, which is a major agent in skin infections. We observed moderate activities (MIC values of between 0.1 and 0.5 mg/ml) for E. faecalis, Vibrio spp., and Bacillus spp. Neither compound was active against Salmonella spp., E. coli and K. pneumoniae (MICs > 1 mg/ml). To conclude, the high antimicrobial activity of D. thouarsii leaf extracts against S. aureus supports its traditional use to treat skin infections. 相似文献
15.
Chenyu Piao Ling Ling Junwei Zhao Liying Jin Shanwen Jiang Xiaowei Guo Xiangjing Wang Wensheng Xiang 《Antonie van Leeuwenhoek》2018,111(10):1835-1843
Two novel Gram-stain positive, spore-forming, aerobic actinomycetes, designated NEAU-PCY-1T and NEAU-PCY-2, were isolated from rhizosphere soil of Urtica urens L. collected from Anshan, Liaoning Province, northeast China. The 16S rRNA gene sequence analysis showed that strains NEAU-PCY-1T and NEAU-PCY-2 exhibited 99.8% similarity with each other and are closely related to Streptomyces abietis DSM 42080T (98.2, 98.3%) and Streptomyces fildesensis DSM 41987T (98.0, 98.1%). Phylogenetic analysis based on the 16S rRNA gene sequences indicated that the two strains formed a cluster with these two closely related species. Moreover, DNA–DNA hybridization results and some phenotypic, physiological and biochemical properties differentiated the two strains from their close relatives in the genus Streptomyces. Based on a polyphasic taxonomy study, strains NEAU-PCY-1T and NEAU-PCY-2 are considered to represent a novel species of the genus Streptomyces, for which the name Streptomyces urticae sp. nov. is proposed, with NEAU-PCY-1T (=?DSM 105115T?=?CCTCC AA 2017015T) as the type strain. 相似文献
16.
Quintana ET Wierzbicka K Mackiewicz P Osman A Fahal AH Hamid ME Zakrzewska-Czerwinska J Maldonado LA Goodfellow M 《Antonie van Leeuwenhoek》2008,93(3):305-313
Nine strains isolated from mycetoma patients and received as Streptomyces somaliensis were the subject of a polyphasic taxonomic study. The organisms shared chemical markers consistent with their classification
in the genus Streptomyces and formed two distinct monophyletic subclades in the Streptomyces 16S rRNA gene tree. The first subclade contained four organisms, including the type strain of S. somaliensis, and the second clade the remaining five strains which had almost identical 16S rRNA sequences. Members of the two subclades
were sharply separated using DNA:DNA relatedness and phenotypic data which also showed that the subclade 1 strains formed
an heterogeneous group. In contrast, the subclade 2 strains were assigned to a single genomic species and had identical phenotypic
profiles. It is evident from these data that the subclade 2 strains should be recognised as a new species of Streptomyces. The name proposed for this new species is Streptomyces sudanensis sp. nov. The type strain is SD 504T (DSM = 41923T = NRRL B-24575T).
Erika T. Quintana and Katarzyna Wierzbicka contributed equally to this work.
The GenBank accession numbers for the 16S rRNA gene sequences of Streptomyces somaliensis DSM 40738T and Streptomyces sudanensis DSM 41607, DSM 41608, DSM 41609, SD 504T and SD 509 are EF540897, EF540898, EF540999, EF515876 and EF540900. 相似文献
17.
A new actinobacterium strain, designated 2AT, was isolated from a soil sample collected from Guru Nanak Dev University, Punjab (India) and characterized using a polyphasic taxonomic approach. It showed antimicrobial activity against various Gram-positive and Gram-negative bacteria including drug resistant bacteria and fungi. The strain had chemotaxononomic and morphological properties typical of the genus Streptomyces. The 16S rRNA gene sequence of the strain showed 99.9, 99.5 and 99.5 % similarity with Streptomyces flavotricini DSM 40152T, Streptomyces toxytricini DSM 40178T and Streptomyces globosus DSM 40815T, respectively. This strain formed a coherent cluster with them and shared DNA–DNA homology of 37.6 ± 0.6, 34.4 ± 0.5 and 33.1 ± 0.4 % with type strains, S. flavotricini DSM 40152T, S. globosus DSM 40815T and S. toxytricini DSM 40178T, respectively. Further, the strain was readily distinguished from the phylogenetic close relatives in a variety of morphological, physiological and biochemical properties. Based on the genotypic and phenotypic characteristics, it is proposed that strain 2AT represents a novel species in the genus Streptomyces, for which the name Streptomyces amritsarensis sp. nov. is proposed, with the type strain 2AT (=MTCC 11845T=JCM 19660T). 相似文献
18.
Chao Yu Chongxi Liu Xiangjing Wang Junwei Zhao Lingyu Yang Ruixia Gao Yuejing Zhang Wensheng Xiang 《Antonie van Leeuwenhoek》2013,104(6):1013-1019
A novel actinomycete, designated strain NEAU-ycm1T, was isolated from an edible Chinese black ant (Polyrhachis vicina Roger) and characterized with a polyphasic approach. The organism was found to have morphological and chemotaxonomic characteristics typical of streptomycetes. Phylogenetic analysis based on the almost complete 16S rRNA gene sequence show that the novel isolate belongs to the genus Streptomyces and forms a separate subclade. The closest phylogenetic relatives were identified as the type strains of Streptomyces intermedius NBRC 13049T (97.74 %), Streptomyces aureoverticillatus NRRL B-3326T (97.69 %), Streptomyces rutgersensis NBRC 12819T (97.68 %), Streptomyces gougerotii NBRC 3198T (97.68 %) and Streptomyces diastaticus subsp. diastaticus NBRC 3714T (97.68 %). Similarities to other type strains of the genus Streptomyces were lower than 97.55 %. A comparison between strain NEAU-ycm1T and the closest related Streptomyces type strains revealed that it is different from them in morphological, physiological and biochemical characteristics. Therefore, it is proposed that NEAU-ycm1T (=CGMCC 4.7094T = DSM 42102T) represents a novel species of the genus of Streptomyces, for which the name Streptomyces polyrhachii sp. nov. is proposed. 相似文献
19.
Aims: To investigate the ability of bacilli of various species (Bacillus clausii, Bacillus subtilis, Bacillus lentus, Bacillus pumilus. Bacillus megaterium, Bacillus firmus, Bacillus sp.) and origins (probiotic and collection strains) to counteract the activity of some representative DNA‐reactive agents. Methods and Results: The inhibitory effect of 21 bacilli strains, previously characterized by tDNA‐PCR, on four genotoxins, was examined in vitro using the short‐term assay SOS‐Chromotest. All strains had a high inhibitory activity against 4‐nitroquinoline‐1‐oxide and N‐methyl‐N′‐nitro‐nitrosoguanidine (direct agents), whereas the inhibitory activity was high or moderate against 2‐amino‐3,4‐dimethylimidazo[4,5‐f]quinoline and aflatoxin B1 (indirect agents). Antigenotoxicity was observed in vegetative cells, but not heat‐treated cells or spore suspensions. The spectroscopic properties of compounds were modified after cell co‐incubation and all the strains maintained high viability after exposure to the genotoxins. Conclusions: No relevant differences in antigenotoxicity were evidenced among strains of the examined species or between probiotic and collection strains. Significance and Impact of the Study: Although derived from an in vitro model, the results suggest that Bacillus‐based probiotics could be useful for reducing the gastrointestinal risk originating from genotoxic agents. 相似文献
20.
Jiansheng Lu Yihua Ma Jianjia Liang Yingying Xing Tao Xi Yuanyuan Lu 《Microbiological research》2012,167(10):590-595
A marine-derived actinomycete (Streptomyces sp. WBF16) exhibiting antitumor activities was investigated. The strain was identified using morphological, biochemical and genetic techniques. 16S rDNA sequence of the isolate indicated that it was most closely related to Streptomyces coelicolor A3 (2). Furthermore, a new aureolic acid (Chromomycin B, 1), along with Chromomycin A2 (2) and Chromomycin A3 (3) were isolated from its secondary metabolites. Their structures were determined by chemical and spectroscopic methods including 1D, 2D NMR and HRMS. Compounds 1–3 showed strong cytotoxicity against SGC7901, HepG2, A549, HCT116 and COC1 and HUVEC. 相似文献