Giuseppina Tommonaro

Marine bacteria associated with sponge as source of cyclic peptides

Two bacteria associated with the marine sponge Ircinia variabilis were isolated using commercial and experimental media. The use of media containing marine derived proteins improved the growth of both isolated bacteria, showing that marine bacteria need of marine derived proteins for a better growth. The composition of free and total fatty acids of both strains cultivated under different carbon source was investigated. Several diketopiperazines were isolated from both bacteria and the hypothesis of their role in the bacterial-spongy interaction is discussed.

Aliphatic and aromatic glycosides from the cell cultures of Lycopersicon esculentum

The beta-D-glucoside, gentiobioside and 6-O-alpha-L-arabinosyl-beta-D-glucoside of benzyl alcohol, androsin and a new simple aliphatic glycoside, isopentylgentiobioside, have been found in the cell cultures of Lycopersicon esculentum. Their structures were elucidated from chemical and spectroscopic evidence.

Synthesis and Biological Activities of Thio-avarol Derivatives

Eleven new thio-avarol derivatives (3-13) were synthesized. Their antimicrobial, brine shrimp lethality, and free-radical scavenging activities and acetylcholinesterase inhibition, together with 12 already reported semisynthetic thio-avarol derivatives (14-25), were evaluated. Structure-activity relationships among these thio derivatives were determined.

Diketopiperazines produced by the Halophilic Archaeon, "Haloterrigena hispanica", activate AHL bioreporters

The generic term “quorum sensing” has been adopted to describe the bacterial cell-to-cell communication mechanism which coordinates gene expression when the population has reached a high cell density. Quorum sensing depends on the synthesis of small molecules that diffuse in and out of bacterial cells. There are few reports about this mechanism in Archaea. We report the isolation and chemical characterization of small molecules belonging to class of diketopiperazines (DKPs) in Haloterrigena hispanica, an extremely halophilic archaeon. One of the DKPs isolated, the compound cyclo-(l-prolyl–l-valine) activated N-acyl homoserine lactone (AHL) bioreporters, indicating that Archaea may have the ability to interact with AHL-producing bacteria within mixed communities.

Exocellular Cyclic Dipeptides from a Ruegeria Strain Associated with Cell Cultures of Suberites domuncula

From cell cultures of Suberites domuncula was isolated a bacterial strain, SDC-1, which was identified by 16S ribosomal RNA sequence analysis as an α-Proteobacterium of the genus Ruegeria. The occurrence of the strain in sponge cell culture could be explained by its resistance to the antibiotics used in the isolation of sponge cell cultures or by the preservation of SDC-1 by host sponge cells. The fatty acid composition of SDC-1 is characterized by branched C-12 methyl fatty acids. Two new and 8 known cyclic dipeptides were isolated and characterized from the fermentation broth of SDC-1. Cyclodipeptides are one of the families of cell-cell signaling compounds and may have some role to play in sponge-bacteria interactions.

Development in primary cell culture of demosponges.

We have established primary cell culture of the marine demosponge Dysidea avara and Suberites domuncula. Microbial contamination was controlled by the use of a pool of antibiotics confirming the goodness of this procedure. Effect of pH, temperature and light was studied to establish the better growth conditions. The comparison of lipid composition of sponge and cells suggested a series of experiments to optimise the medium. A glucose dose-dependent experiment showed that the ideal glucose concentration is 1 g l(-1). Supplementing the medium with unsaturated fatty acid and retinol, no promotion of growth was observed, but the compounds were totally metabolised by cells. Increments from 70 to 160% in the number of cells were observed, supplementing the medium with different concentration of cholesterol. These results suggest that the analysis of the chemical composition of sponge and cells give indication on the composition of the nutrient media.

Acetamide Derivatives with Antioxidant Activity and Potential Anti-Inflammatory Activity

This study reports the synthesis and antioxidant activity of some new acetamide derivatives. The compounds’ structures were elucidated by NMR analysis and their melting points were measured. The in vitro antioxidant activity of these compounds was tested by evaluating the amount of scavenged ABTS radical and estimating ROS and NO production in tBOH- or LPS-stimulated J774.A1 macrophages. All compounds were tested for their effect on cell viability by an MTT assay and by a Brine Shrimp Test.

Antioxidative Activity and Lycopene and β-Carotene Contents in Different Cultivars of Tomato (Lycopersicon Esculentum)

Nine different Lycopersicon esculentum varieties were analysed in order to determine differences in the antioxidant activity, both hydrophilic and lipophilic. To assess the nutritional value of all varieties, the total content of principal carotenoids, lycopene, and β-carotene was also analysed. On the basis of analyses performed on all lipophilic fractions, we can affirm that the total antioxidant activity of tomato is due to the integrated action of different compounds instead of that of any single compound such as lycopene and β-carotene. Anticytotoxic activities by brine shrimps assay were also tested on all lipophilic fractions to evaluate potential antitumoral activity.

Polysaccharides from Wastes of Vegetable Industrial Processing: New Opportunities for Their Eco-Friendly Re-Use

Polysaccharides are the most abundant natural biopolymers and represent by far the largest group of polymers produced in the world: indeed more than 150,000 M tons of polysaccharides per year are produced in comparison with about 140 M tons of synthetic polymers (Navard, 2005). Polysaccharides are widely diffused in nature: they can be found in plants, animals and microorganisms, performing different fundamental biological functions. Depending on their functional role, they can be distinguished in: energy reserve substances (e.g. starch or inulin in plants, glycogen in animals), structural elements maintaining mechanical shape and rigidity of the living cells (cellulose, hemicellulose and pectin in plant cell wall, chitin in arthropod exoskeletons), and water-binding elements (agar, pectin and alginates in plants, mucopolysaccharides in animals). About 99% of total natural polysaccharides are located in plants and vegetables that consequently represent a major renewable source of these biopolymers exploitable for different purposes. Indeed, polysaccharides are presently used in all sectors of human activities and in several application such as: food nutrients, food additives and feed production; material science concerning the formulation of polymeric materials for different biotechnological applications; health care for biocompatible materials, drug delivery or as source of biologically active molecules; sustainable energy production by means of biofuels generation (Persin et al., 2010). The main and most abundant polysaccharides from plants and vegetables include starch, cellulose and hemicelluloses, inulin and pectins that, thanks to their useful physicalchemical properties such as emulsifying power, viscoelasticity, polyelectrolyte conformation, adherence, bio-compatibility, stabilizing power, et cetera are usually exploited in the above mentioned fields of application. In addition, several other polysaccharides with different structures and properties are continuously isolated and are under investigation in relation to their features and potential employment in several industrial sectors.

A Novel Cyclopeptide from a Bacterium Associated with the Marine Sponge Ircinia muscarum

Abstract A new cyclotetrapeptide 1, together with three known cyclopeptides were isolated from the exo-cellular extract of Pseudomonas sp. a bacterium associated with the sponge Ircinia muscarum. The structure of 1 was suggested on the basis of spectroscopic analytical data and chemical degradation.