Search results for "biologia generale"

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

2015

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)

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

2015

Synthesis, cytotoxicity, and inhibitory effects on tubulin polymerization of a new 3-heterocyclo substituted 2-styrylquinazolinones

2004

In order to study the influence of 3-substitution on the cytotoxic activity of 2-styrylquinazolinones, new 6-chloro-2-styryl-3-(heteroaryl)-4(3H)-quinazolinones were synthesized by refluxing equimolar amounts of 6-chloro-2-methyl-3-(heteroaryl)-4(3H)-quinazolinones and benzaldehyde in glacial acetic acid. At 1 microg ml(-1) concentration, almost all 2-styrylquinazolinones showed some cytotoxic activity against the L1210 and K562 leukemia cell lines. However, only 6-chloro-2-styryl-3-(pyrimidin-2yl)-4(3H)-quinazolinone inhibited the growth of these cells by over 50%. This last compound was also the only member of the series that inhibited tubulin polymerization, with an IC(50) value of 5.8 v…

A peptide from human β thymosin as a platform for the development of new anti-biofilm agents for Staphylococcus spp. and Pseudomonas aeruginosa

2016

Conventional antibiotics might fail in the treatment of biofilm-associated infections causing infection recurrence and chronicity. The search for antimicrobial peptides has been performed with the aim to discover novel anti-infective agents active on pathogens in both planktonic and biofilm associated forms. The fragment 9-19 of human thymosin β4 was studied through 1 μs MD simulation. Two main conformations of the peptide were detected, both constituted by a central hydrophobic core and by the presence of peripheral charged residues suggesting a possible mechanism of interaction with two models of biological membranes, related to eukaryotic or bacterial membrane respectively. In addition, …

Sortase A Inhibitors: Recent Advances and Future Perspectives

2015

Here, we describe the most promising small synthetic organic compounds that act as potent Sortase A inhibitors and cater the potential to be developed as antivirulence drugs. Sortase A is a polypeptide of 206 amino acids, which catalyzes two sequential reactions: (i) thioesterification and (ii) transpeptidation. Sortase A is involved in the process of bacterial adhesion by anchoring LPXTG-containing proteins to lipid II. Sortase A inhibitors do not affect bacterial growth, but they restrain the virulence of pathogenic bacterial strains, thereby preventing infections caused by Staphylococcus aureus or other Gram-positive bacteria. The efficacy of the most promising inhibitors needs to be com…

Comprehensive analysis of a Vibrio parahaemolyticus strain extracellular serine protease VpSP37

2015

Proteases play an important role in the field of tissue dissociation combined with regenerative medicine. During the years new sources of proteolytic enzymes have been studied including proteases from different marine organisms both eukaryotic and prokaryotic. Herein we have purified a secreted component of an isolate of Vibrio parahaemolyticus, with electrophoretic mobilities corresponding to 36 kDa, belonging to the serine proteases family. Sequencing of the N-terminus enabled the in silico identification of the whole primary structure consisting of 345 amino acid residues with a calculated molecular mass of 37.4 KDa. The purified enzyme, named VpSP37, contains a Serine protease domain be…

Unravelling the DNA sequences carried by Streptomyces coelicolor membrane vesicles

2022

AbstractMembrane vesicles (MVs) are spherical particles with nanoscale dimensions and characterized by the presence of diverse cargos, such as nucleic acids, proteins, lipids, and cellular metabolites. Many examples of (micro)organisms producing MVs are reported in literature. Among them, bacterial MVs are of particular interest because they are now considered as the fourth mechanism of horizontal gene transfer. Streptomyces bacteria are well-known for their ecological roles and ability to synthesize bioactive compounds, with Streptomyces coelicolor being the model organism. It was previously demonstrated that it can produce distinct populations of MVs characterized by different protein and…

Impact of water stress on plant water relations, growth and mycorhization of Acacia tortilis ssp. raddiana: Interactions of the stress severity and d…

2010

Mycorrhizae are commonly reported to improve drought resistance of the host plant. Investigating factors controlling the plant-resistance strategy to water stress can however lead to a suitable management of mycorrhizal plants under drought. Here, we focused on the impact of interactions of the AM fungal species and water stress severity and duration on mycorrhizal Acacia tortilis ssp. raddiana in terms of plant growth, mycorhization and water relations. We used three Glomus species, which were G. mosseae, G. deserticola and G. intraradices. We applied three watering regimes that were maximum water holding non-stress regime, mild-severe water stress and severe water stress. Measurements wer…

Photosynthesized silver-polyaminocyclodextrin nanocomposites as promising antibacterial agents with improved activity

2016

Ag nanocomposites were prepared by photoreduction of ammoniacal silver acetate in the presence of poly-{6-[3-(2-(3-aminopropylamino)ethylamino)propylamino]}-(6-deoxy)-β-CD (amCD). The obtained systems were characterized by means of various complementary techniques (UV-vis, FT-IR, TEM, SAED). In particular, FT-IR spectroscopy evidenced a partial oxidative degradation of the polyamine branches of the capping auxiliary, due to the fact that these groups function as a sacrificial reducing agent in the photoinduced formation of the Ag metal core. TEM and SAED micrographs showed that the Ag cores possess a relatively low polydispersity and a significantly crystalline character. The Ag–amCD system…

Biogenic iron-silver nanoparticles inhibit bacterial biofilm formation due to Ag+ release as determined by a novel phycoerythrin-based assay

2020

Silver nanoparticles (Ag-NPs) can be considered as a cost-effective alternative to antibiotics. In the presence of Fe(III)-citrate and Ag+, Klebsiella oxytoca DSM 29614 produces biogenic Ag-NPs embedded in its peculiar exopolysaccharide (EPS). K. oxytoca DSM 29614 was cultivated in a defined growth medium–containing citrate (as sole carbon source) and supplemented with Ag+ and either low or high Fe(III) concentration. As inferred from elemental analysis, transmission and scanning electron microscopy, Fourier transform infrared spectrometry and dynamic light scattering, Ag-EPS NPs were produced in both conditions and contained also Fe. The production yield of high-Fe/Ag-EPS NPs was 12 times …