The microbial community of the coelomic fluid of the sea urchin Paracentrotus lividus

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

Infrastrutture e paesaggio nella "città in estensione"

L’esperienza didattica e di ricerca presentata nel saggio prende le mosse dall’attivazione di un laboratorio di laurea magistrale in Progettazione Architettonica diretto dal prof. Palazzotto e sviluppato nell’ambito del corso di laurea in Architettura dell’omonimo Dipartimento presso l’Università degli Studi di Palermo. Il laboratorio ha visto la partecipazione complessiva di 11 laureandi, che hanno esitato le proprie tesi negli anni compresi tra il 2013 e il 2015. Il laboratorio di laurea, facendo propria l’idea di “città-campagna” avanzata da Giuseppe Samonà nel 1976 – che porta con sé un esplicito riferimento a identità formali e spaziali specifiche intese a conferire allʼambito della ca…

Elucidating the molecular physiology of lantibiotic NAI-107 production in Microbispora ATCC-PTA-5024.

Background The filamentous actinomycete Microbispora ATCC-PTA-5024 produces the lantibiotic NAI-107, which is an antibiotic peptide effective against multidrug-resistant Gram-positive bacteria. In actinomycetes, antibiotic production is often associated with a physiological differentiation program controlled by a complex regulatory and metabolic network that may be elucidated by the integration of genomic, proteomic and bioinformatic tools. Accordingly, an extensive evaluation of the proteomic changes associated with NAI-107 production was performed on Microbispora ATCC-PTA-5024 by combining two-dimensional difference in gel electrophoresis, mass spectrometry and gene ontology approaches. R…

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…

Tryptophan promotes morphological and physiological differentiation in Streptomyces coelicolor.

The molecular mechanisms regulating tryptophan biosynthesis in actinomycetes are poorly understood; similarly, the possible roles of tryptophan in the differentiation program of microorganism life-cycle are still underexplored. To unveil the possible regulatory effect of this amino acid on gene expression, an integrated study based on quantitative teverse transcription-PCR (qRT-PCR) and proteomic approaches was performed on the actinomycete model Streptomyces coelicolor. Comparative analyses on the microorganism growth in a minimal medium with or without tryptophan supplementation showed that biosynthetic trp gene expression in S. coelicolor is not subjected to a negative regulation by the …

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…

The small protein SCO2038 controls Streptomyces coelicolor differentiation by modulating tryptophan biosynthesis

Background In Streptomyces coelicolor amino acid metabolism is an important clue of the morphological and physiological differentiation program and, differently from other bacteria, the expression of amino acid biosynthetic genes is not subjected to endproduct negative regulation. In some amino acid biosynthetic gene clusters, such as tryptophan, histidine and proline, small orfs (about 100-300 nucleotides) were identified. These small orfs, such as sco2038, encode proteins whose cellular role have to be elucidated to highlight possible novel and crucial molecular mechanisms controlling amino acid synthesis and, thus, differentiation program. Objectives The aims of this work are: 1. the und…

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

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…

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…

Composition and geographic variation of the bacterial microbiota associated with the coelomic fluid of the sea urchin Paracentrotus lividus

AbstractIn the present work, culture-based and culture-independent investigations were performed to determine the microbiota structure of the coelomic fluid of Mediterranean sea urchin Paracentrotus lividus individuals collected from two distinct geographical sites neighboring a high-density population bay and a nature reserve, respectively. Next Generation Sequencing analysis of 16S rRNA gene (rDNA) showed that members of the Proteobacteria, Bacteroidetes and Fusobacteria phyla, which have been previously reported to be commonly retrieved from marine invertebrates, dominate the overall population of microorganisms colonizing this liquid tissue, with minority bacterial genera exhibiting rem…

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)