scholarly journals Discovery of new antibacterial accramycins from a genetic variant of the soil bacterium, Streptomyces sp. MA37

2020 ◽  
Author(s):  
Fleurdeliz Maglangit ◽  
Yuting Zhang ◽  
Kwaku Kyeremeh ◽  
Hai Deng
Keyword(s):  
Wild Type Strain ◽  
Biosynthetic Gene Cluster ◽  
Multidrug Resistant ◽  
Regulatory Genes ◽  
Negative Regulator ◽  
Clinical Isolates ◽  
Wild Type ◽  
In The Wild ◽  
A Minor ◽  
New Metabolites

AbstractContinued mining of natural products from the strain Streptomyces sp. MA37 in our laboratory led to the discovery of a minor specialised metabolite (SM) called accramycin A. Owing to its low yield (0.2mg/L) in the wild type strain, we investigated the roles of regulatory genes in the corresponding biosynthetic gene cluster (acc BGC) through gene inactivation with the aim of improving the titre of this compound. One of the resulting mutants (ΔaccJ) dramatically upregulated the production of accramycin A 1 by 330-fold (66mg/L). Furthermore, ten new metabolites, accramycins B-K 2-11, were discovered, together with two known compounds, naphthacemycin B112 and fasamycin C 13 from the mutant extract. This suggested that accJ, annotated as Multiple Antibiotic Resistance Regulator (MarR), is a negative regulator gene in the accramycin biosynthesis. Compounds 1-13 inhibited the Gram-positive pathogens (S. aureus, E. faecalis) and clinical isolates, E. faecium (K59-68 and K60-39), and S. haemolyticus with minimal inhibitory concentration (MIC) values in the range of 1.5-12.5µg/mL. Remarkably, compounds 1-13 displayed superior activity against K60-39 (MIC = 3.1-6.3µg/mL) than ampicillin (MIC = 25µg/mL), and offer promising potential for the development of accramycin-based antibiotics that target multidrug-resistant Enterococcus clinical isolates. Our results highlight the importance of identifying the roles of regulatory genes in natural product discovery.

scholarly journals Discovery of New Antibacterial Accramycins from a Genetic Variant of the Soil Bacterium, Streptomyces sp. MA37

Biomolecules ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. 1464
Author(s):  
Fleurdeliz Maglangit ◽  
Yuting Zhang ◽  
Kwaku Kyeremeh ◽  
Hai Deng
Keyword(s):  
Wild Type Strain ◽  
Biosynthetic Gene Cluster ◽  
Multidrug Resistant ◽  
Regulatory Genes ◽  
Negative Regulator ◽  
Clinical Isolates ◽  
Streptomyces Sp ◽  
In The Wild ◽  
A Minor ◽  
New Metabolites

Continued mining of natural products from the strain Streptomyces sp. MA37 in our laboratory led to the discovery of a minor specialized metabolite (SM) called accramycin A. Owing to its low yield (0.2 mg/L) in the wild type strain, we investigated the roles of regulatory genes in the corresponding biosynthetic gene cluster (acc BGC) through gene inactivation with the aim of improving the titer of this compound. One of the resulting mutants (∆accJ) dramatically upregulated the production of accramycin A 1 by 330-fold (66 mg/L). Furthermore, ten new metabolites, accramycins B–K 2–11, were discovered, together with two known compounds, naphthacemycin B112 and fasamycin C 13 from the mutant extract. This suggested that accJ, annotated as multiple antibiotic resistance regulator (MarR), is a negative regulator gene in the accramycin biosynthesis. Compounds 1–13 inhibited the Gram-positive pathogens (Staphylococcus aureus, Enterococcus faecalis) and clinical isolates Enterococcus faecium (K59-68 and K60-39) and Staphylococcus haemolyticus with minimal inhibitory concentration (MIC) values in the range of 1.5–12.5 µg/mL. Remarkably, compounds 1–13 displayed superior activity against K60-39 (MIC = 3.1–6.3 µg/mL) compared to ampicillin (MIC = 25 µg/mL), and offered promising potential for the development of accramycin-based antibiotics that target multidrug-resistant Enterococcus clinical isolates. Our results highlight the importance of identifying the roles of regulatory genes in natural product discovery.

scholarly journals Mutations in Four Regulatory Genes Have Interrelated Effects on Heterocyst Maturation in Anabaena sp. Strain PCC 7120

2006 ◽  
Vol 188 (21) ◽  
pp. 7387-7395 ◽  
Author(s):  
Sigal Lechno-Yossef ◽  
Qing Fan ◽  
Shigeki Ehira ◽  
Naoki Sato ◽  
C. Peter Wolk
Keyword(s):  
Type Strain ◽  
Wild Type Strain ◽  
Response Regulator ◽  
Regulatory System ◽  
Transcript Abundance ◽  
Regulatory Genes ◽  
Wild Type ◽  
Serine Threonine Kinase ◽  
In The Wild ◽  
Pcc 7120

ABSTRACT Regulatory genes hepK, hepN, henR, and hepS are required for heterocyst maturation in Anabaena sp. strain PCC 7120. They presumptively encode two histidine kinases, a response regulator, and a serine/threonine kinase, respectively. To identify relationships between those genes, we compared global patterns of gene expression, at 14 h after nitrogen step-down, in corresponding mutants and in the wild-type strain. Heterocyst envelopes of mutants affected in any of those genes lack a homogeneous, polysaccharide layer. Those of a henR mutant also lack a glycolipid layer. patA, which encodes a positive effector of heterocyst differentiation, was up-regulated in all mutants except the hepK mutant, suggesting that patA expression may be inhibited by products related to heterocyst development. hepS and hepK were up-regulated if mutated and so appear to be negatively autoregulated. HepS and HenR regulated a common set of genes and so appear to belong to one regulatory system. Some nontranscriptional mechanism may account for the observation that henR mutants lack, and hepS mutants possess, a glycolipid layer, even though both mutations down-regulated genes involved in formation of the glycolipid layer. HepK and HepN also affected transcription of a common set of genes and therefore appear to share a regulatory pathway. However, the transcript abundance of other genes differed very significantly from expression in the wild-type strain in either the hepK or hepN mutant while differing very little from wild-type expression in the other of those two mutants. Therefore, hepK and hepN appear to participate also in separate pathways.

scholarly journals Improvement of Nemadectin Production by Overexpressing the Regulatory Gene nemR and Nemadectin Biosynthetic Gene Cluster in Streptomyces Cyaneogriseus

2021 ◽  
Author(s):  
Yuan-Jie Wu ◽  
Song-Bai Yang ◽  
Zheng-Yu Zhang ◽  
Shao-Xin Chen
Keyword(s):  
Gene Cluster ◽  
Wild Type Strain ◽  
Regulatory Gene ◽  
Anthelmintic Activity ◽  
Biosynthetic Gene Cluster ◽  
Wild Type ◽  
Transcription Level ◽  
Positive Role ◽  
C 23 ◽  
In The Wild

AbstractNemadectin, a 16-member macrocyclic lactone antiparasitic antibiotic, is produced by Streptomyces cyaneogriseus subspecies noncyanogenus. Moxidectin, a C-23 oximate derivative of nemadectin, is widely used as a pesticide due to its broad-spectrum, highly efficient, and safe anthelmintic activity. NemR, a LAL family regulator, is encoded by nemR and is involved in nemadectin biosynthesis in S. cyaneogriseus. In this report, gene disruption and complementation experiments showed that nemR plays a positive role in the biosynthesis of nemadectin. The transcription level of nemadectin biosynthetic genes in the nemR knockout strain was significantly decreased compared with those in the wild-type strain MOX-101. However, overexpression of nemR under the control of native or strong constitutive promoters resulted in the opposite, increasing the production of nemadectin by 56.5 or 73.5%, respectively, when compared with MOX-101. In addition, the gene cluster of nemadectin biosynthesis was further cloned and overexpressed using a CRISPR method, which significantly increase nemadectin yield by 108.6% (509 mg/L) when compared with MOX-101.

scholarly journals Roles offkbNin Positive Regulation andtcs7in Negative Regulation of FK506 Biosynthesis in Streptomyces sp. Strain KCTC 11604BP

2012 ◽  
Vol 78 (7) ◽  
pp. 2249-2255 ◽  
Author(s):  
SangJoon Mo ◽  
Young Ji Yoo ◽  
Yeon Hee Ban ◽  
Sung-Kwon Lee ◽  
Eunji Kim ◽  
...  
Keyword(s):  
Type Strain ◽  
Wild Type Strain ◽  
Regulatory Protein ◽  
Strain Improvement ◽  
Transcriptional Regulators ◽  
Biosynthetic Gene Cluster ◽  
Wild Type ◽  
Biosynthetic Genes ◽  
Content Type ◽  
In The Wild

ABSTRACTFK506 is an important 23-member polyketide macrolide with immunosuppressant activity. Its entire biosynthetic gene cluster was previously cloned fromStreptomycessp. strain KCTC 11604BP, and sequence analysis identified three putative regulatory genes,tcs2,tcs7, andfkbN, which encode proteins with high similarity to the AsnC family transcriptional regulators, LysR-type transcriptional regulators, and LAL family transcriptional regulators, respectively. Overexpression and in-frame deletion oftcs2did not affect the production of FK506 or co-occurring FK520 compared to results for the wild-type strain, suggesting thattcs2is not involved in their biosynthesis.fkbNoverexpression improved the levels of FK506 and FK520 production by approximately 2.0-fold, and a deletion offkbNcaused the complete loss of FK506 and FK520 production. Although the overexpression oftcs7decreased the levels of FK506 and FK520 production slightly, a deletion oftcs7caused 1.9-fold and 1.5-fold increases in FK506 and FK520 production, respectively. Finally,fkbNoverexpression in thetcs7deletion strain resulted in a 4.0-fold (21 mg liter−1) increase in FK506 production compared to that by the wild-type strain. This suggests thatfkbNencodes a positive regulatory protein essential for FK506/FK520 biosynthesis and that the gene product oftcs7negatively regulates their biosynthesis, demonstrating the potential of exploiting this information for strain improvement. Semiquantitative reverse transcription-PCR (RT-PCR) analyses of the transcription levels of the FK506 biosynthetic genes in the wild-type and mutant strains proved that most of the FK506 biosynthetic genes are regulated byfkbNin a positive manner and negatively bytcs7.

scholarly journals Regulation of the Biosynthesis of the Macrolide Antibiotic Spiramycin in Streptomyces ambofaciens

2010 ◽  
Vol 192 (21) ◽  
pp. 5813-5821 ◽  
Author(s):  
Fatma Karray ◽  
Emmanuelle Darbon ◽  
Hoang Chuong Nguyen ◽  
Josette Gagnat ◽  
Jean-Luc Pernodet
Keyword(s):  
Expression Analysis ◽  
Wild Type Strain ◽  
Macrolide Antibiotic ◽  
Regulatory Gene ◽  
Biosynthetic Gene Cluster ◽  
Wild Type ◽  
Rt Pcr ◽  
Reverse Transcription Pcr ◽  
Streptomyces Ambofaciens ◽  
In The Wild

ABSTRACT Streptomyces ambofaciens synthesizes the macrolide antibiotic spiramycin. The biosynthetic gene cluster for spiramycin has been characterized for S. ambofaciens. In addition to the regulatory gene srmR (srm22), previously identified (M. Geistlich et al., Mol. Microbiol. 6:2019-2029, 1992), three putative regulatory genes had been identified by sequence analysis. Gene expression analysis and gene inactivation experiments showed that only one of these three genes, srm40, plays a major role in the regulation of spiramycin biosynthesis. The disruption of srm22 or srm40 eliminated spiramycin production while their overexpression increased spiramycin production. Expression analysis was performed by reverse transcription-PCR (RT-PCR) for all the genes of the cluster in the wild-type strain and in the srm22 (srmR) and srm40 deletion mutants. The results from the expression analysis, together with the ones from the complementation experiments, indicated that Srm22 is required for srm40 expression, Srm40 being a pathway-specific activator that controls most, if not all, of the spiramycin biosynthetic genes.

scholarly journals Effects of Mutations of RAD50, RAD51, RAD52, and Related Genes on Illegitimate Recombination in Saccharomyces cerevisiae

Genetics ◽  
1996 ◽  
Vol 142 (2) ◽  
pp. 383-391 ◽  
Author(s):  
Yasumasa Tsukamoto ◽  
Jun-ichi Kato ◽  
Hideo Ikeda
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Quantitative Analysis ◽  
Structural Analysis ◽  
Recombination Rate ◽  
Type Strain ◽  
Negative Selection ◽  
Wild Type Strain ◽  
Illegitimate Recombination ◽  
Wild Type ◽  
In The Wild

Abstract To examine the mechanism of illegitimate recombination in Saccharomyces cerevisiae, we have developed a plasmid system for quantitative analysis of deletion formation. A can1 cyh2 cell carrying two negative selection markers, the CAN1 and CYH2 genes, on a YCp plasmid is sensitive to canavanine and cycloheximide, but the cell becomes resistant to both drugs when the plasmid has a deletion over the CAN1 and CYH2 genes. Structural analysis of the recombinant plasmids obtained from the resistant cells showed that the plasmids had deletions at various sites of the CAN1-CYH2 region and there were only short regions of homology (1-5 bp) at the recombination junctions. The results indicated that the deletion detected in this system were formed by illegitimate recombination. Study on the effect of several rad mutations showed that the recombination rate was reduced by 30-, 10-, 10-, and 10-fold in the rad52, rad50, mre11, and xrs2 mutants, respectively, while in the rud51, 54, 55, and 57 mutants, the rate was comparable to that in the wild-type strain. The rad52 mutation did not affect length of homology at junction sites of illegitimate recombination.

scholarly journals Mutations of folC cause increased susceptibility to sulfamethoxazole in Mycobacterium tuberculosis

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Ruiqi Wang ◽  
Kun Li ◽  
Jifang Yu ◽  
Jiaoyu Deng ◽  
Yaokai Chen
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Type Strain ◽  
Wild Type Strain ◽  
Clinical Isolates ◽  
Aminobenzoic Acid ◽  
Wild Type ◽  
Dihydropteroate Synthase ◽  
Expression Levels ◽  
Encoding Gene ◽  
Increased Susceptibility

AbstractPrevious studies showed that mutation of folC caused decreased expression of the dihydropteroate synthase encoding gene folP2 in Mycobacterium tuberculosis (M. tuberculosis). We speculated that mutation of folC in M. tuberculosis might affect the susceptibility to sulfamethoxazole (SMX). To prove this, 53 clinical isolates with folC mutations were selected and two folC mutants (I43A, I43T) were constructed based on M. tuberculosis H37Ra. The results showed that 42 of the 53 clinical isolates (79.2%) and the two lab-constructed folC mutants were more sensitive to SMX. To probe the mechanism by which folC mutations make M. tuberculosis more sensitive to SMX, folP2 was deleted in H37Ra, and expression levels of folP2 were compared between H37Ra and the two folC mutants. Although deletion of folP2 resulted in increased susceptibility to SMX, no difference in folP2 expression was observed. Furthermore, production levels of para-aminobenzoic acid (pABA) were compared between the folC mutants and the wild-type strain, and results showed that folC mutation resulted in decreased production of pABA. Taken together, we show that folC mutation leads to decreased production of pABA in M. tuberculosis and thus affects its susceptibility to SMX, which broadens our understanding of mechanisms of susceptibilities to antifolates in this bacterium.

scholarly journals Expression and function of the cdgD gene, encoding a CHASE–PAS-DGC-EAL domain protein, in Azospirillum brasilense

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
José Francisco Cruz-Pérez ◽  
Roxana Lara-Oueilhe ◽  
Cynthia Marcos-Jiménez ◽  
Ricardo Cuatlayotl-Olarte ◽  
María Luisa Xiqui-Vázquez ◽  
...  
Keyword(s):  
Azospirillum Brasilense ◽  
Type Strain ◽  
Wild Type Strain ◽  
Soil Conditions ◽  
Wild Type ◽  
Gene Encoding ◽  
Wheat Roots ◽  
Genes Encoding ◽  
In The Wild ◽  
Plant Growth Promoting

AbstractThe plant growth-promoting bacterium Azospirillum brasilense contains several genes encoding proteins involved in the biosynthesis and degradation of the second messenger cyclic-di-GMP, which may control key bacterial functions, such as biofilm formation and motility. Here, we analysed the function and expression of the cdgD gene, encoding a multidomain protein that includes GGDEF-EAL domains and CHASE and PAS domains. An insertional cdgD gene mutant was constructed, and analysis of biofilm and extracellular polymeric substance production, as well as the motility phenotype indicated that cdgD encoded a functional diguanylate protein. These results were correlated with a reduced overall cellular concentration of cyclic-di-GMP in the mutant over 48 h compared with that observed in the wild-type strain, which was recovered in the complemented strain. In addition, cdgD gene expression was measured in cells growing under planktonic or biofilm conditions, and differential expression was observed when KNO3 or NH4Cl was added to the minimal medium as a nitrogen source. The transcriptional fusion of the cdgD promoter with the gene encoding the autofluorescent mCherry protein indicated that the cdgD gene was expressed both under abiotic conditions and in association with wheat roots. Reduced colonization of wheat roots was observed for the mutant compared with the wild-type strain grown in the same soil conditions. The Azospirillum-plant association begins with the motility of the bacterium towards the plant rhizosphere followed by the adsorption and adherence of these bacteria to plant roots. Therefore, it is important to study the genes that contribute to this initial interaction of the bacterium with its host plant.

scholarly journals Blocks in the pseudouridimycin pathway unlock hidden metabolites in the Streptomyces producer strain

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Marianna Iorio ◽  
Sahar Davatgarbenam ◽  
Stefania Serina ◽  
Paolo Criscenzo ◽  
Mitja M. Zdouc ◽  
...  
Keyword(s):  
Gene Clusters ◽  
Biosynthetic Gene Cluster ◽  
Systematic Investigation ◽  
Biosynthetic Gene ◽  
Wild Type ◽  
Bacterial Rna ◽  
Soil Isolate ◽  
Mutant Strains ◽  
In The Wild ◽  
Polymerase Inhibitor

AbstractWe report a metabolomic analysis of Streptomyces sp. ID38640, a soil isolate that produces the bacterial RNA polymerase inhibitor pseudouridimycin. The analysis was performed on the wild type, on three newly constructed and seven previously reported mutant strains disabled in different genes required for pseudouridimycin biosynthesis. The results indicate that Streptomyces sp. ID38640 is able to produce, in addition to lydicamycins and deferroxiamines, as previously reported, also the lassopeptide ulleungdin, the non-ribosomal peptide antipain and the osmoprotectant ectoine. The corresponding biosynthetic gene clusters were readily identified in the strain genome. We also detected the known compound pyridindolol, for which we propose a previously unreported biosynthetic gene cluster, as well as three families of unknown metabolites. Remarkably, the levels of most metabolites varied strongly in the different mutant strains, an observation that enabled detection of metabolites unnoticed in the wild type. Systematic investigation of the accumulated metabolites in the ten different pum mutants identified shed further light on pseudouridimycin biosynthesis. We also show that several Streptomyces strains, able to produce pseudouridimycin, have distinct genetic relationship and metabolic profile with ID38640.

Characterization of Enterococcus faecium mutants resistant to mundticin KS, a class IIa bacteriocin

Microbiology ◽  
2003 ◽  
Vol 149 (10) ◽  
pp. 2901-2908 ◽  
Author(s):  
Youko Sakayori ◽  
Mizuho Muramatsu ◽  
Satoshi Hanada ◽  
Yoichi Kamagata ◽  
Shinichi Kawamoto ◽  
...  
Keyword(s):  
Enterococcus Faecium ◽  
Antimicrobial Agents ◽  
Wild Type Strain ◽  
Unsaturated Fatty Acids ◽  
Class I ◽  
Wild Type ◽  
Food Preservatives ◽  
In The Wild ◽  
Resistant Mutants

The emergence and spread of mutants resistant to bacteriocins would threaten the safety of using bacteriocins as food preservatives. To determine the physiological characteristics of resistant mutants, mutants of Enterococcus faecium resistant to mundticin KS, a class IIa bacteriocin, were isolated. Two types of mutant were found that had different sensitivities to other antimicrobial agents such as nisin (class I) and kanamycin. Both mutants were resistant to mundticin KS even in the absence of Mg2+ ions. The composition of unsaturated fatty acids in the resistant mutants was significantly increased in the presence of mundticin KS. The composition of the phospholipids in the two resistant mutants also differed from those in the wild-type strain. The putative zwitterionic amino-containing phospholipid in both mutants significantly increased, whereas amounts of phosphatidylglycerol and cardiolipin decreased. These changes in membrane structure may influence resistance of enterococci to class IIa and class I bacteriocins.

Sign in / Sign up

Export Citation Format

Share Document