Streptomyces coelicolor secretoma protects astrocytes from oxidative stress

Streptomycetes are gram-positive bacteria that produce about 2/3 of pharmaceutically active secondary metabolites, such as antibiotics, and anti-tumor, immunosuppressive, antifungal and antiparasitic agents. In this study, we investigated the possible effects of Streptomyces coelicolor extracts and putative vesicular fraction on primary cultures of rat astrocytes, in both physiological and stressed conditions, induced by treatment with hydrogen peroxide. Briefly, crude extracts and putative vesicular fractions were prepared from two S.coelicolor strains (M145 wild-type strain and bold F166 strain), and used to treat primary astrocytes, which were then also treated with hydrogen peroxide. Da…

Metabolic pathways in Microbispora sp. ATCC-PTA 5024, producer of NAI-107 lantibiotic

A "fat" Streptomycete strain overproduces antibiotics

Characterization of the bacterial community isolated from a High Middle Age soil sample dated since 980 AD

THE SMALL PROTEIN SCO2038 CONTROLS TRYPTOPHAN BIOSYNTHESIS AND DIFFERENTIATION IN STREPTOMYCES COELICOLOR

The cellular regulatory factors comprise regulatory proteins, small RNA and small proteins. It is known that the product of small orfs (smorfs) can regulate the translation of downstream elements and also can encode functional peptides involved in the regulation of specific pathways (Ladoukakis E. et al.,2011). In particular, in the model streptomycete Sfreptomyces coelicolor, smorfs (about 100-300 nucleotides) were identified in some amino acid biosynthetic gene clusters such as in the tryptophan trpCXBA locus (Limauro D. et al., I 990; Hu DS. et al., 1999). In S. coelicolor the molecular mechanisms that regulate tryptophan (Trp) biosynthesis are poorly understood and, unlike the trp opero…

Multi-omics of Pseudoalteromonas haloplanktis TAC125: a quest for antimicrobial metabolic pathways

Backgrounds The Antarctic strain Pseudoalteromonas haloplanktis TAC125 is one of the model organisms of cold-adapted bacteria and is currently exploited as a new alternative expression host for numerous biotechnological applications. Interestingly, this bacterium has been reported to be able to inhibit the growth of Burkholderia cepacia complex (Bcc) strains, opportunistic pathogens responsible for the infection of immune-compromised patients. Most likely, this occurs through the synthesis of several different compounds, including Volatile Organic Compounds (VOCs), whose nature and characteristics are currently mostly unknown. Objectives To obtain a complete picture of cellular processes di…

Characterization of the microbiota from coelomic fluid of the sea urchin Paracentrotus lividus

The study of the microbiota is a subject of considerable and growing interest since it is drawing new important perspectives in the life sciences concerning the functional relationships between metazoans and microbial cells. In fact, it has already shown that the endogenous microbial community affects various physiological activities of multicellular organisms. The coelomic cavity of echinoderms contains a fluid in which coelomocytes are reported to exert immune functions like phagocytosis, opsonization and production of antimicrobial agents against marine bacteria [1, 2]. However, up to day nothing is known about the endogenous bacterial population of coelomic fluid. We focused on this iss…

PCL/PEG based membranes for bacterial cells immobilization stimulate actinorhodin antibiotic production in S. coelicolor

The actinomycetes, Gram-positive filamentous bacteria, are the most prolific source of natural antibiotics. At industrial level, antibiotics from actinomycetes are usually produced at low levels by mean of fermentative processes in submerged cultivations, where one of the major factors negatively affecting bioproductivity is the phenomenon of a pellet-shaped biomass growth. The strategies based on cell-immobilization, which were already proven improving bacterial bioprocess productivity, could stimulate antibiotic production in actinomycetes.

Actinorhodin production intensification by nanofibrous membranes in Streptomyces coelicolor cultures

In this work, electrospun polycaprolactone (PCL) and polylactic acid (PLA) membranes, subjected or not to O2-plasma treatment, werwe used as support for cell-immobilization in S. coelicolor immobilized-cells created a compact biofilm on both kinds of membranes.

Enhancement of antibiotic productions by plasma modified PLA electrospun membranes in Streptomyces coelicolor immobilized-cell cultivations

This study, encouraging the use of PLA membranes for actinomycetes cultivations, could unveil functional insights associated with antibiotic production and S. coelicolor cellimmobilization

Improvement of actinorhodin production yield in Streptomyces coelicolor by immobilized-cell cultivations by using PCL- and PLA-based films

Actinomycetes are Gram-positive bacteria producing most of naturally occurring antibiotics (Donadio et al., 2010). At industrial level, antibiotics are produced by submerged fermentations where the actinomycete filamentous morphology negatively affects bioproductivity (van Dissel et al., 2014). Microporous membranes for bacterial cell-immobilization were already proven increasing bioproductivity in Streptomyces coelicolor, that is a model actinomycete producing the blue pigmented actinorhodin (ACT) antibiotic (Scaffaro et al., 2016). To develop an immobilized-cell bioreactor system, different kinds of polycaprolactone (PCL) and polylactic acid (PLA) films were produced by an electrospinning…

Genetic manipulation of spiramycin-producing strain Streptomyces ambofaciens ATCC 23877 by φC31 Att/Int system-based vectors results in a significant reduction of antibiotic production

The genus Streptomyces produces about two-thirds of naturally occurring antibiotics and many other biologically active secondary metabolites. The genetic manipulation of Streptomycetes is often labor and time intensive due to their large genome and complex development. Much progress has been made to develop gene transfer methods useful to construct antibiotic-producing strains with improved properties. The φC31 Att/Int system is an integration system that has been widely used to produce stable recombinants in Actinomycetes and its integration site is an attB site located in a pirin-like gene (pirA) of the bacterial chromosome. In this study we demonstrate that the integration of φC31 DNA in…

Endophytes from medicinal plants’ seeds: exploring new reservoirs of bioactive molecules

Plant-associated microorganisms have recently gained more attention for their influence on plant health and biotechnological relevance. Bioactive molecules have been already isolated from plant-associated bacteria. Seed-borne bacterial endophytes have not been much explored though. Such endophytes are particularly important, since they can influence germination and be transmitted from generation to generation. Interestingly, seed endophytes from medicinal plants could influence the production of molecules with therapeutic properties. Bacterial endophytic strains were extracted from surface-sterilized seeds of the medicinal plant Echinacea purpurea and their 16S rRNA genes were sequenced. Th…

Effect of Streptomyces coelicolor M145 cell immobilization on actinorhodin production

Non previsto

trpX: a small orf involved in S. coelicolor tryptophan metabolism

The seed endophytic microbiota of Citrus limon L. Burm. F

Background Plant seeds possess a complex microbiota which may play a crucial rolein a plethora of mechanisms, such as preservation, germination, seedling development, plant growth and health. In particular, seed endophytic microbiota is gaining more and more consideration due to the fact that it may be vertically transmitted to ensure individual competitive advantages. The Citrusspecies, including C.limon,areone of the most economically important evergreen fruit crops in the world. Objectives i)Identification and characterization ofmicrobial isolates from Citrus limon L. Burm. F. seed endosphere. ii) Structure of Citrus limon L. Burm. F. seed endosphytic microbiota. Methods -Surface-sterili…

THE SMALL PROTEIN TRPM MODULATES MORPHO-PHYSIOLOGICAL DIFFERENTIATION IN THE MODEL ACTINOMYCETE STREPTOMYCES COELICOLOR A3(2)

BACKGROUNDS TrpM, a small protein of 63 amino acids, modulates tryptophan (Trp) metabolism and morpho-physiological differentiation in the filamentous bacterium Streptomyces coelicolor A3(2), a model organism for antibiotic production and cell differentiation. Indeed, the trpM knock-out mutant strain is characterized by a delayed growth on minimal medium, smaller aerial hyphae, and reduction of both spore and antibiotic actinorhodin production in comparison with the wild-type strain. These observations were in agreement with proteomic analyses which highlighted a role for TrpM in controlling i) Trp production through Trp precursor availability and, thus ii) bacterial growth and morpho-physi…

IMPROVED PRODUCTION OF THE ANTIBIOTIC ACTINORHODIN IN STREPTOMYCES COELICOLOR IMMOBILIZED-MYCELIAL CELL CULTIVATIONS

Objectives i) Evaluation of ACT production in Streptomyces coelicolor M145 mycelial cells immobilized on polycaprolactone (PCL) and polylactic acid (PLA) nanofiber membranes, modified or not by an O2- plasma treatment. ii) Identification of gene products associated with the improvement of ACT production.

The small protein TrpM modulates morpho-physiological differentiation in Streptomyces coelicolor

TrpM, a small protein of 63 amino acids, is encoded by a gene of the trpCMBA locus involved in tryptophan biosynthesis in the model actinomycete Streptomyces coelicolor. Indeed, the trpM knock-out mutant strain is characterized by a delayed growth on minimal medium, smaller aerial hyphae, and reduction of both spore and antibiotic actinorhodin production in comparison with the wild-type strain. These observations are in agreement with proteomic analyses which highlighted a role for TrpM in controlling i) tryptophan production through precursor availability and, thus ii) bacterial growth and morpho-physiological differentiation. To further elucidate the role of TrpM, a S. coelicolor trpM kno…

Omics approaches to elucidate the molecular physiology of lantibiotc NAI-107 production in Microbispora ATCC-PTA-5024

The small protein SCO2038 modulates tryptophan biosynthesis and morpho-physiological differentiation in Streptomyces coelicolor

In Streptomyces coelicolor small open reading frames were identified in several amino acids biosynthetic gene clusters, like SCO2038 (trpX) in the tryptophan trpCXBA locus. Here, the role of SCO2038, encoding a 63 amino acid protein, was investigated by both phenotypic and molecular analyses. A SCO2038 knockout mutant strain showed a delayed growth on minimal medium (MM), compromised actinorhodin biosynthesis and poor sporulation. The capability of this mutant to grow on MM was restored by tryptophan’s and its precursors’ supplementation. Pulldown and bacterial two hybrid assays revealed SCO2038 interaction with PepA, which is putatively involved in the metabolism of serine, glycine and cys…

Compartmentalization of biosynthetic enzymes in bacterial cells: the histidine metabolic pathway case

Introduction: It is known that the inner concentration of proteins within the cell cytoplasm is so high that limits the diffusion of enzymes and metabolic intermediates, leading to a loss of time and energy. Therefore, the organization of genes in operons would have enabled to have enzymes involved in the same metabolic pathway physically close to each other. A corollary to this hypothesis in the possibility of physical interactions between the enzymes of the same metabolic pathway, resulting in the formation of a supramolecular complex capable in channeling the intermediates from one enzyme to a physical adjacent one, with restricted diffusion in the surrounding milieu. Objectives: The aim…

Proteomics to elucidate the molecular physiology of Microbispora sp. ATCC-PTA-5024, the producer of NAI-107, a very promising lantibiotic

The filamentous actinobacterium Microbispora sp. ATCC-PTA-5024 produces the lantibiotic NAI-107 (Maffioli et al., 2014), which is effective against multidrug-resistant Gram-positive pathogens (Jabés et al., 2011). In actinomycetes, the biosynthesis of antibiotics is generally elicited as a physiological response controlled by a complex regulatory network involving global regulators, playing pleiotropic roles, and pathway-specific regulators, which activate the biosynthesis of biologically active molecules (Bibb, 2005)