• Monitoring Protein Secretion in Using Fluorescent Proteins.

      Hamed, Mohamed Belal; Vrancken, Kristof; Bilyk, Bohdan; Koepff, Joachim; Novakova, Renata; van Mellaert, Lieve; Oldiges, Marco; Luzhetskyy, Andriy; Kormanec, Jan; Anné, Jozef; Karamanou, Spyridoula; Economou, Anastassios; HIPS, Helmholtz-Institut für Pharmazeutische Forschung Saarland, Universitätscampus E8.1 66123 Saarbrücken, Germany. (2018-12-07)
      Fluorescent proteins are a major cell biology tool to analyze protein sub-cellular topology. Here we have applied this technology to study protein secretion in the Gram-positive bacterium Streptomyces lividans TK24, a widely used host for heterologous protein secretion biotechnology. Green and monomeric red fluorescent proteins were fused behind Sec (SPSec) or Tat (SPTat) signal peptides to direct them through the respective export pathway. Significant secretion of fluorescent eGFP and mRFP was observed exclusively through the Tat and Sec pathways, respectively. Plasmid over-expression was compared to a chromosomally integrated spSec-mRFP gene to allow monitoring secretion under high and low level synthesis in various media. Fluorimetric detection of SPSec-mRFP recorded folded states, while immuno-staining detected even non-folded topological intermediates. Secretion of SPSec-mRFP is unexpectedly complex, is regulated independently of cell growth phase and is influenced by the growth regime. At low level synthesis, highly efficient secretion occurs until it is turned off and secretory preforms accumulate. At high level synthesis, the secretory pathway overflows and proteins are driven to folding and subsequent degradation. High-level synthesis of heterologous secretory proteins, whether secretion competent or not, has a drastic effect on the endogenous secretome, depending on their secretion efficiency. These findings lay the foundations of dissecting how protein targeting and secretion are regulated by the interplay between the metabolome, secretion factors and stress responses in the S. lividans model.
    • Heterologous Expression of the Nybomycin Gene Cluster from the Marine StrainStreptomyces albus subsp. NRRL B-24108.

      Rodríguez Estévez, Marta; Myronovskyi, Maksym; Gummerlich, Nils; Nadmid, Suvd; Luzhetskyy, Andriy; HIPS, Helmholtz-Institut für pharmazeutische Forschung Saarland, Universitätscampus E8.1, 66123 Saarbrücken, Germany. (MDPI, 2018-11-04)
      Streptomycetes represent an important reservoir of active secondary metabolites with potential applications in the pharmaceutical industry. The gene clusters responsible for their production are often cryptic under laboratory growth conditions. Characterization of these clusters is therefore essential for the discovery of new microbial pharmaceutical drugs. Here, we report the identification of the previously uncharacterized nybomycin gene cluster from the marine actinomycete
    • Genome Engineering Approaches to Improve Nosokomycin A Production by Streptomyces ghanaensis B38.3

      Kuzhyk, Yuriy; Lopatniuk, Maria; Luzhetskyy, Andriy; Fedorenko, Victor; Ostash, Bohdan; HIPS, Helmholtz-Institut für Pharmazeutische Forschung Saarland, Universitätscampus E8.1 66123 Saarbrücken, Germany. (Springer, 2018-09-25)
      Here we describe our efforts to improve the levels of phosphoglycolipid antibiotic nosokomycin A production by Streptomyces ghanaensis ATCC14672 via genome engineering approaches. Introduction of two extra copies of leucyl tRNA (UUA) gene bldA and one copy of moenomycin biosynthesis gene cluster led, on average, to threefold increase in nosokomycin A titers (up to 1.5 mg/L). Our results validate genome engineering approach as a viable strategy to improve moenomycin production.
    • A set of synthetic versatile genetic control elements for the efficient expression of genes in Actinobacteria.

      Horbal, Lilya; Siegl, Theresa; Luzhetskyy, Andriy; HIPS, Helmholtz-Institut für pharmazeutische Forschung Saarland, Universitätscampus 8.1, 66123 Saarbrücken, Germany. (2018-01-11)
      The design and engineering of secondary metabolite gene clusters that are characterized by complicated genetic organization, require the development of collections of well-characterized genetic control elements that can be reused reliably. Although a few intrinsic terminators and RBSs are used routinely, their translation and termination efficiencies have not been systematically studied in Actinobacteria. Here, we analyzed the influence of the regions surrounding RBSs on gene expression in these bacteria. We demonstrated that inappropriate RBSs can reduce the expression efficiency of a gene to zero. We developed a genetic device - an in vivo RBS-selector - that allows selection of an optimal RBS for any gene of interest, enabling rational control of the protein expression level. In addition, a genetic tool that provides the opportunity for measurement of termination efficiency was developed. Using this tool, we found strong terminators that lead to a 17-100-fold reduction in downstream expression and are characterized by sufficient sequence diversity to reduce homologous recombination when used with other elements. For the first time, a C-terminal degradation tag was employed for the control of protein stability in Streptomyces. Finally, we describe a collection of regulatory elements that can be used to control metabolic pathways in Actinobacteria.
    • Multi-Omics and Targeted Approaches to Determine the Role of Cellular Proteases in Protein Secretion.

      Busche, Tobias; Tsolis, Konstantinos C; Koepff, Joachim; Rebets, Yuriy; Rückert, Christian; Hamed, Mohamed B; Bleidt, Arne; Wiechert, Wolfgang; Lopatniuk, Mariia; Yousra, Ahmed; Anné, Jozef; Karamanou, Spyridoula; Oldiges, Marco; Kalinowski, Jörn; Luzhetskyy, Andriy; Economou, Anastassios; HIPS, Helmholtz-Institut für pharmazeutische Forschung Saarland, Universitätscampus 8.1, 66123 Saarbrücken, Germany. (2018-01-01)
    • New Alpiniamides From sp. IB2014/011-12 Assembled by an Unusual Hybrid Non-ribosomal Peptide Synthetase -AT Polyketide Synthase Enzyme.

      Paulus, Constanze; Rebets, Yuriy; Zapp, Josef; Rückert, Christian; Kalinowski, Jörn; Luzhetskyy, Andriy; HIPS, Helmholtz-Institut füt Pharmazeutische Forschung Saarland, Universitätscampus E8.1 66123 Saarbrücken, Germany. (2018-01-01)
      he environment of Lake Baikal is a well-known source of microbial diversity. The strain Streptomyces sp. IB2014/011-12, isolated from samples collected at Lake Baikal, was found to exhibit potent activity against Gram-positive bacteria. Here, we report isolation and characterization of linear polyketide alpiniamide A (1) and its new derivatives B–D (2–5). The structures of alpiniamides A–D were established and their relative configuration was determined by combination of partial Murata’s method and ROESY experiment. The absolute configuration of alpiniamide A was established through Mosher’s method. The gene cluster, responsible for the biosynthesis of alpiniamides (alp) has been identified by genome mining and gene deletion experiments. The successful expression of the cloned alp gene cluster in a heterologous host supports these findings. Analysis of the architecture of the alp gene cluster and the feeding of labeled precursors elucidated the alpiniamide biosynthetic pathway. The biosynthesis of alpiniamides is an example of a rather simple polyketide assembly line generating unusual chemical diversity through the combination of domain/module skipping and double bond migration events.
    • Characterization of Sigma Factor Genes in streptomyces lividans TK24 Using a Genomic Library-Based Approach for Multiple Gene Deletions.

      Rebets, Yuriy; Tsolis, Konstantinos C; Guðmundsdóttir, Elísabet Eik; Koepff, Joachim; Wawiernia, Beata; Busche, Tobias; Bleidt, Arne; Horbal, Liliya; Myronovskyi, Maksym; Ahmed, Yousra; Wiechert, Wolfgang; Rückert, Christian; Hamed, Mohamed B; Bilyk, Bohdan; Anné, Jozef; Friðjónsson, Ólafur; Kalinowski, Jörn; Oldiges, Marco; Economou, Anastassios; Luzhetskyy, Andriy; HIPS, Helmholtz-Institut für Pharmazeutische Forschung Saarland, Universitätscampus E8.1 66123 Saarbrücken, Germany. (Frontiers, 2018-01-01)
      Alternative sigma factors control numerous aspects of bacterial life, including adaptation to physiological stresses, morphological development, persistence states and virulence. This is especially true for the physiologically complex actinobacteria. Here we report the development of a robust gene deletions system for Streptomyces lividans TK24 based on a BAC library combined with the λ-Red recombination technique. The developed system was validated by systematically deleting the most highly expressed genes encoding alternative sigma factors and several other regulatory genes within the chromosome of S. lividans TK24. To demonstrate the possibility of large scale genomic manipulations, the major part of the undecylprodigiosin gene cluster was deleted as well. The resulting mutant strains were characterized in terms of morphology, growth parameters, secondary metabolites production and response to thiol-oxidation and cell-wall stresses. Deletion of SLIV_12645 gene encoding S. coelicolor SigR1 ortholog has the most prominent phenotypic effect, resulted in overproduction of actinorhodin and coelichelin P1 and increased sensitivity to diamide. The secreted proteome analysis of SLIV_12645 mutant revealed SigR1 influence on trafficking of proteins involved in cell wall biogenesis and refactoring. The reported here gene deletion system will further facilitate work on S. lividans strain improvement as a host for either secondary metabolites or protein production and will contribute to basic research in streptomycetes physiology, morphological development, secondary metabolism. On the other hand, the systematic deletion of sigma factors encoding genes demonstrates the complexity and conservation of regulatory processes conducted by sigma factors in streptomycetes
    • Identification of butenolide regulatory system controlling secondary metabolism in Streptomyces albus J1074.

      Ahmed, Yousra; Rebets, Yuriy; Tokovenko, Bogdan; Brötz, Elke; Luzhetskyy, Andriy; Helmholtz-Institut für pharmazeutische Forschung Saarland,Universitätscampus E8.1, 66123 Saarbrücken, Germany. (2017-08-29)
      A large majority of genome-encrypted chemical diversity in actinobacteria remains to be discovered, which is related to the low level of secondary metabolism genes expression. Here, we report the application of a reporter-guided screening strategy to activate cryptic polycyclic tetramate macrolactam gene clusters in Streptomyces albus J1074. The analysis of the S. albus transcriptome revealed an overall low level of secondary metabolism genes transcription. Combined with transposon mutagenesis, reporter-guided screening resulted in the selection of two S. albus strains with altered secondary metabolites production. Transposon insertion in the most prominent strain, S. albus ATGSal2P2::TN14, was mapped to the XNR_3174 gene encoding an unclassified transcriptional regulator. The mutant strain was found to produce the avenolide-like compound butenolide 4. The deletion of the gene encoding a putative acyl-CoA oxidase, an orthologue of the Streptomyces avermitilis avenolide biosynthesis enzyme, in the S. albus XNR_3174 mutant caused silencing of secondary metabolism. The homologues of XNR_3174 and the butenolide biosynthesis genes were found in the genomes of multiple Streptomyces species. This result leads us to believe that the discovered regulatory elements comprise a new condition-dependent system that controls secondary metabolism in actinobacteria and can be manipulated to activate cryptic biosynthetic pathways.
    • Properties of Streptomyces albus J1074 mutant deficient in tRNA(Leu)UAA gene bldA.

      Koshla, Oksana; Lopatniuk, Maria; Rokytskyy, Ihor; Yushchuk, Oleksandr; Dacyuk, Yuriy; Fedorenko, Victor; Luzhetskyy, Andriy; Ostash, Bohdan; Helmholtz Institut für phsarmazeutische Forschung Saarland (HIPS), Universitätscampus E8.1, 66123 Saarbrücken, Germany. (2017-05-20)
      Streptomyces albus J1074 is one of the most popular and convenient hosts for heterologous expression of gene clusters directing the biosynthesis of various natural metabolic products, such as antibiotics. This fuels interest in elucidation of genetic mechanisms that may limit secondary metabolism in J1074. Here, we report the generation and initial study of J1074 mutant, deficient in gene bldA for tRNA(Leu)UAA, the only tRNA capable of decoding rare leucyl TTA codon in Streptomyces. The bldA deletion in J1074 resulted in a highly conditional Bld phenotype, with depleted formation of aerial hyphae on certain solid media. In addition, bldA mutant of J1074 was unable to produce endogenous antibacterial compounds and two heterologous antibiotics, moenomycin and aranciamycin, whose biosynthesis is directed by TTA-containing genes. We have employed a new TTA codon-specific β-galactosidase reporter system to provide genetic evidence that J1074 bldA mutant is impaired in translation of TTA. In addition, we have discussed the possible reasons for differences in the phenotypes of bldA mutants described here and in previous studies, providing knowledge to study bldA-based regulation of antibiotic biosynthesis.
    • Complete Draft Genome Sequence of the Actinobacterium Nocardiopsis sinuspersici UTMC102 (DSM 45277(T)), Which Produces Serine Protease.

      Tokovenko, Bogdan; Rückert, Christian; Kalinowski, Jörn; Mohammadipanah, Fatemeh; Wink, Joachim; Rosenkränzer, Birgit; Myronovskyi, Maksym; Luzhetskyy, Andriy; Helmholtz Institut für pharmazeutische Forschung Saarland, Universitätscampus E8.1, 66123 Saarbrücken, Germany. (2017-05-18)
      The genome sequence of alkalohalophilic actinobacterium Nocardiopsis sinuspersici UTMC102 is provided. N. sinuspersici UTMC102 produces a highly active serine alkaline protease, and contains at least 11 gene clusters encoding the biosynthesis of secondary metabolites. The N. sinuspersici UTMC102 genome was assembled into a single chromosomal scaffold.
    • Draft Genome Sequence of Streptomyces sp. Strain IB2014011-1, Isolated from Trichoptera sp. Larvae of Lake Baikal.

      Axenov-Gribanov, Denis V; Tokovenko, Bogdan T; Rebets, Yuriy V; Voytsekhovskaya, Irina V; Shatilina, Zhanna M; Protasov, Eugenii S; Luzhetskyy, Andriy N; Timofeyev, Maxim A; Helmholtz Institut für pharmazeutische Forschung Saarland, Universitätscampus E8.1, 66123 Saarbrücken, Germany. (2017-04-27)
      Unique ecosystems with specific environmental conditions have been proven to be a promising source for isolation of new actinobacterial strains. Ancient Lake Baikal is one of the greatest examples of an ecosystem with high species biodiversity and endemicity caused by long-lasting isolated evolution and stable environmental conditions. Herein we report the draft genome sequence of Streptomyces sp. strain IB2014011-1, which was isolated from insect Trichoptera sp. larvae collected at the bottom of Lake Baikal.
    • New natural products identified by combined genomics-metabolomics profiling of marine Streptomyces sp. MP131-18.

      Paulus, Constanze; Rebets, Yuriy; Tokovenko, Bogdan; Nadmid, Suvd; Terekhova, Larisa P; Myronovskyi, Maksym; Zotchev, Sergey B; Rückert, Christian; Braig, Simone; Zahler, Stefan; Kalinowski, Jörn; Luzhetskyy, Andriy; Helmholtz-Institut für Pharmazeutische Forschung Saarland, Universitätscampus E8.1, 66123 Saarbrücken, Germany. (2017-02-10)
      Marine actinobacteria are drawing more and more attention as a promising source of new natural products. Here we report isolation, genome sequencing and metabolic profiling of new strain Streptomyces sp. MP131-18 isolated from marine sediment sample collected in the Trondheim Fjord, Norway. The 16S rRNA and multilocus phylogenetic analysis showed that MP131-18 belongs to the genus Streptomyces. The genome of MP131-18 isolate was sequenced, and 36 gene clusters involved in the biosynthesis of 18 different types of secondary metabolites were predicted using antiSMASH analysis. The combined genomics-metabolics profiling of the strain led to the identification of several new biologically active compounds. As a result, the family of bisindole pyrroles spiroindimicins was extended with two new members, spiroindimicins E and F. Furthermore, prediction of the biosynthetic pathway for unusual α-pyrone lagunapyrone isolated from MP131-18 resulted in foresight and identification of two new compounds of this family - lagunapyrones D and E. The diversity of identified and predicted compounds from Streptomyces sp. MP131-18 demonstrates that marine-derived actinomycetes are not only a promising source of new natural products, but also represent a valuable pool of genes for combinatorial biosynthesis of secondary metabolites.
    • Chromosomal position effect influences the heterologous expression of genes and biosynthetic gene clusters in Streptomyces albus J1074.

      Bilyk, Bohdan; Horbal, Liliya; Luzhetskyy, Andriy; Helmholz-Institut für pharmazeutische Forschung , Josef-Schneider-Straße2,97080 Würzburg, Germany. (2017-01-04)
      Efforts to construct the Streptomyces host strain with enhanced yields of heterologous product have focussed mostly on engineering of primary metabolism and/or the deletion of endogenous biosynthetic gene clusters. However, other factors, such as chromosome compactization, have been shown to have a significant influence on gene expression levels in bacteria and fungi. The expression of genes and biosynthetic gene clusters may vary significantly depending on their location within the chromosome. Little is known about the position effect in actinomycetes, which are important producers of various industrially relevant bioactive molecules.
    • Dual control system - A novel scaffolding architecture of an inducible regulatory device for the precise regulation of gene expression.

      Horbal, L; Luzhetskyy, A; Helmholtz Institut für Pharmazeutische Forschung Saarland, Universitätscampus E8.1, 66123 Saarbrücken, Germany. (2016-09)
      Here, we present a novel scaffolding architecture of an inducible regulatory device. This dual control system is completely silent in the off stage and is coupled to the regulation of gene expression at both the transcriptional and translational levels. This system also functions as an AND gate. We demonstrated the effectiveness of the cumate-riboswitch dual control system for the control of pamamycin production in Streptomyces albus. Placing the cre recombinase gene under the control of this system permitted the construction of synthetic devices with non-volatile memory that sense the signal and respond by altering DNA at the chromosomal level, thereby producing changes that are heritable. In addition, we present a library of synthetic inducible promoters based on the previously described cumate switch. With only one inducer and different promoters, we demonstrate that simultaneous modulation of the expression of several genes to different levels in various operons is possible. Because all modules of the AND gates are functional in bacteria other than Streptomyces, we anticipate that these regulatory devices can be used to control gene expression in other Actinobacteria. The features described in this study make these systems promising tools for metabolic engineering and biotechnology in Actinobacteria.
    • A gene cluster for the biosynthesis of moenomycin family antibiotics in the genome of teicoplanin producer Actinoplanes teichomyceticus.

      Horbal, Liliya; Ostash, Bohdan; Luzhetskyy, Andriy; Walker, Suzanne; Kalinowski, Jorn; Fedorenko, Victor; Helmholtz-Institute for Pharmaceutical Research Saarland (HIPS),Saarland Universitätscampus E8.1, 66123 Saarbrücken, Germany. (2016-09)
      Moenomycins are phosphoglycolipid antibiotics notable for their extreme potency, unique mode of action, and proven record of use in animal nutrition without selection for resistant microflora. There is a keen interest in manipulation of structures of moenomycins in order to better understand their structure-activity relationships and to generate improved analogs. Only two almost identical moenomycin biosynthetic gene clusters are known, limiting our knowledge of the evolution of moenomycin pathways and our ability to genetically diversify them. Here, we report a novel gene cluster (tchm) that directs production of the phosphoglycolipid teichomycin in Actinoplanes teichomyceticus. Its overall genetic architecture is significantly different from that of the moenomycin biosynthesis (moe) gene clusters of Streptomyces ghanaensis and Streptomyces clavuligerus, featuring multiple gene rearrangements and two novel structural genes. Involvement of the tchm cluster in teichomycin biosynthesis was confirmed via heterologous co-expression of amidotransferase tchmH5 and moe genes. Our work sets the background for further engineering of moenomycins and for deeper inquiries into the evolution of this fascinating biosynthetic pathway.
    • Post-translational Serine/Threonine Phosphorylation and Lysine Acetylation: A Novel Regulatory Aspect of the Global Nitrogen Response Regulator GlnR in S. coelicolor M145.

      Amin, Rafat; Franz-Wachtel, Mirita; Tiffert, Yvonne; Heberer, Martin; Meky, Mohamed; Ahmed, Yousra; Matthews, Arne; Krysenko, Sergii; Jakobi, Marco; Hinder, Markus; Moore, Jane; Okoniewski, Nicole; Maček, Boris; Wohlleben, Wolfgang; Bera, Agnieszka; HIPS, Helmholtz-Institut für pharmazeutische Forschung Saarland, Universitätscampus E8.1, 66123 Saarbrücken, Germany. (Frontiers, 2016-01-01)
      Soil-dwelling Streptomyces bacteria such as S.coelicolor have to constantly adapt to the nitrogen (N) availability in their habitat. Thus, strict transcriptional and post-translational control of the N-assimilation is fundamental for survival of this species. GlnR is a global response regulator that controls transcription of the genes related to the N-assimilation in S. coelicolor and other members of the Actinomycetales. GlnR represents an atypical orphan response regulator that is not activated by the phosphorylation of the conserved aspartate residue (Asp 50). We have applied transcriptional analysis, LC-MS/MS analysis and electrophoretic mobility shift assays (EMSAs) to understand the regulation of GlnR in S. coelicolor M145. The expression of glnR and GlnR-target genes was revisited under four different N-defined conditions and a complex N-rich condition. Although, the expression of selected GlnR-target genes was strongly responsive to changing N-concentrations, the glnR expression itself was independent of the N-availability. Using LC-MS/MSanalysis we demonstrated that GlnR was post-translationally modified. The post-translational modifications of GlnR comprise phosphorylation of the serine/threonine residues and acetylation of lysine residues. In the complex N-rich medium GlnR was phosphorylated on six serine/threonine residues and acetylated on one lysine residue. Under defined N-excess conditions only two phosphorylated residues were detected whereas under defined N-limiting conditions no phosphorylation was observed. GlnR phosphorylation is thus clearly correlated with N-rich conditions. Furthermore, GlnR was acetylated on four lysine residues independently of the N-concentration in the defined media and on only one lysine residue in the complex N-rich medium. Using EMSAs we demonstrated that phosphorylation inhibited the binding of GlnR to its targets genes, whereas acetylation had little influence on the formation of GlnR-DNA complex. This study clearly demonstrated that GlnR DNA-binding affinity is modulated by post-translational modifications in response to changing N-conditions in order to elicit a proper transcriptional response to the latter.
    • Cloning and Heterologous Expression of the Grecocycline Biosynthetic Gene Cluster.

      Bilyk, Oksana; Sekurova, Olga N; Zotchev, Sergey B; Luzhetskyy, Andriy N; Helmholtz Institut für Pharmazeutische Forschung Saarland, Universitätscampus E8.1, 66123 Saarbrücken, Germany. (2016)
      Transformation-associated recombination (TAR) in yeast is a rapid and inexpensive method for cloning and assembly of large DNA fragments, which relies on natural homologous recombination. Two vectors, based on p15a and F-factor replicons that can be maintained in yeast, E. coli and streptomycetes have been constructed. These vectors have been successfully employed for assembly of the grecocycline biosynthetic gene cluster from Streptomyces sp. Acta 1362. Fragments of the cluster were obtained by PCR and transformed together with the "capture" vector into the yeast cells, yielding a construct carrying the entire gene cluster. The obtained construct was heterologously expressed in S. albus J1074, yielding several grecocycline congeners. Grecocyclines have unique structural moieties such as a dissacharide side chain, an additional amino sugar at the C-5 position and a thiol group. Enzymes from this pathway may be used for the derivatization of known active angucyclines in order to improve their desired biological properties.
    • Actinobacteria Isolated from an Underground Lake and Moonmilk Speleothem from the Biggest Conglomeratic Karstic Cave in Siberia as Sources of Novel Biologically Active Compounds.

      Axenov-Gibanov, Denis V; Voytsekhovskaya, Irina V; Tokovenko, Bogdan T; Protasov, Eugeniy S; Gamaiunov, Stanislav V; Rebets, Yuriy V; Luzhetskyy, Andriy N; Timofeyev, Maxim A; Helmholtz Institute for Pharmaceutical Research Saarland (HIPS), Saarbrucken, Germany, 3 Universität des Saarlandes–Pharmazeutische Biotechnologie, Saarbrucken, Germany. (2016)
      Actinobacteria isolated from unstudied ecosystems are one of the most interesting and promising sources of novel biologically active compounds. Cave ecosystems are unusual and rarely studied. Here, we report the isolation and characterization of ten new actinobacteria strains isolated from an ancient underground lake and moonmilk speleothem from the biggest conglomeratic karstic cave in Siberia with a focus on the biological activity of the obtained strains and the metabolite dereplication of one active strain. Streptomyces genera isolates from moonmilk speleothem demonstrated antibacterial and antifungal activities. Some of the strains were able to inhibit the growth of pathogenic Candida albicans.
    • Testing the utility of site-specific recombinases for manipulations of genome of moenomycin producer Streptomyces ghanaensis ATCC14672.

      Lopatniuk, M; Ostash, B; Makitrynskyy, R; Walker, S; Luzhetskyy, A; Fedorenko, V; Helmholtz Institute for Pharmaceutical Research Saarland,Saarbrücken, Saarland 66123, Germany. (2015-11)
      Streptomyces ghanaensis ATCC14672 is the producer of phosphoglycolipid antibiotics moenomycins that for almost 40 years were used worldwide as an animal feed additive. As the use of moenomycins narrows down (due to bans in the EU and some other countries), it opens the opportunity to develop much-needed antibiotics against Gram-positive human pathogens, such as cocci. It is desirable to develop ATCC14672 strains accumulating only certain members of moenomycin family which would facilitate their purification, analysis and/or chemical modification. Here we tested site-specific recombinases (SSRs) as a tool to manipulate the genome of ATCC14672 and to achieve aforementioned goals. We show that of three SSRs tested - Cre, Dre, and Flp - the first two efficiently catalyzed recombination reactions, while Flp showed no activity in ATCC14672 cells. Cre recombinase can be reused at least three times to modify ATCC14672 genome without detrimental effects, such as large-scale inversions or deletions. Properties of the generated strains and SSRs are discussed.
    • Endophytic Streptomyces in the traditional medicinal plant Arnica montana L.: secondary metabolites and biological activity.

      Wardecki, Tina; Brötz, Elke; De Ford, Christian; von Loewenich, Friederike D; Rebets, Yuriy; Tokovenko, Bogdan; Luzhetskyy, Andriy; Merfort, Irmgard; Helmholtz Institute for Pharmaceutical Research Saarland,Saarbrücken, Saarland 66123, Germany. (2015-08)
      Arnica montana L. is a medical plant of the Asteraceae family and grows preferably on nutrient poor soils in mountainous environments. Such surroundings are known to make plants dependent on symbiosis with other organisms. Up to now only arbuscular mycorrhizal fungi were found to act as endophytic symbiosis partners for A. montana. Here we identified five Streptomyces strains, microorganisms also known to occur as endophytes in plants and to produce a huge variety of active secondary metabolites, as inhabitants of A. montana. The secondary metabolite spectrum of these strains does not contain sesquiterpene lactones, but consists of the glutarimide antibiotics cycloheximide and actiphenol as well as the diketopiperazines cyclo-prolyl-valyl, cyclo-prolyl-isoleucyl, cyclo-prolyl-leucyl and cyclo-prolyl-phenylalanyl. Notably, genome analysis of one strain was performed and indicated a huge genome size with a high number of natural products gene clusters among which genes for cycloheximide production were detected. Only weak activity against the Gram-positive bacterium Staphylococcus aureus was revealed, but the extracts showed a marked cytotoxic activity as well as an antifungal activity against Candida parapsilosis and Fusarium verticillioides. Altogether, our results provide evidence that A. montana and its endophytic Streptomyces benefit from each other by completing their protection against competitors and pathogens and by exchanging plant growth promoting signals with nutrients.