The Marine Bacterium Shewanella woodyi Produces C-HSL to Regulate Bioluminescence.

Quorum sensing (QS), a cell-to-cell communication system involved in the synchronization of bacterial behavior in a cell-density-dependent manner has been shown to control phenotypes such as luminescence, virulence, and biofilm formation. The marine strain, Shewanella woodyi MS32 has been identified as a luminous bacterium. Very little information is known on this bacterium, in particular if its luminescence and biofilm formation are controlled by QS.

Biofilm formation in marine bacteria and biocidal sensitivity: interplay between a potent antibiofilm compound (AS162) and quorum-sensing autoinducers.

The capacity of two homoserine lactones to stimulate the marine bacteria (TC14 strain) for its capacity to form a biofilm when exposed to a potent antibiofilm compound AS162 is reported. Effective concentrations (EC) of AS162 at 24 h, 48 h, and 72 h were, respectively, of 4.3, 4.

Parallel synthesis of a bis-triazoles library as psammaplin A analogues: A new wave of antibiofilm compounds?

Synthesis of psammaplin A analogues is described. Screening for antibiofilm activity of the targeted library afford some interesting elements in terms of structure-activity relationships. Some compounds exhibited EC50 in the range of ampicillin against three strains of gramnegative bacteria without toxic effect.

Screening of bromotyramine analogues as antifouling compounds against marine bacteria.

Rapid and efficient synthesis of 23 analogues inspired by bromotyramine derivatives, marine natural products, by means of CuSO4-catalysed [3+2] alkyne-azide cycloaddition is described. The final target was then assayed for anti-biofilm activity against three Gram-negative marine bacteria, Pseudoalteromonas ulvae (TC14), Pseudoalteromonas lipolytica (TC8) and Paracoccus sp. (4M6).

Characterization and anti-biofilm activity of extracellular polymeric substances produced by the marine biofilm-forming bacterium Pseudoalteromonas ulvae strain TC14.

This study investigated soluble (Sol-EPS), loosely bound (LB-EPS), and tightly bound extracellular polymeric substances (TB-EPS) harvested from biofilm and planktonic cultures of the marine bacterium Pseudoalteromonas ulvae TC14. The aim of the characterization (colorimetric methods, FTIR, GC-MS, NMR, HPGPC, and AFM analyses) was to identify new anti-biofilm compounds; activity was assessed using the BioFilm Ring Test®. A step-wise separation of EPS was designed, based on differences in water-solubility and acidity.

The marine bacteria Shewanella frigidimarina NCIMB400 upregulates the type VI secretion system during early biofilm formation.

Shewanella sp. are facultative anaerobic Gram-negative bacteria, extensively studied for their electron transfer ability. Shewanella frigidimarina has been detected and isolated from marine environments, and in particular, from biofilms.

Modulation of violacein production and phenotypes associated with biofilm by exogenous quorum sensing N-acylhomoserine lactones in the marine bacterium Pseudoalteromonas ulvae TC14.

Various phenotypes ranging from biofilm formation to pigment production have been shown to be regulated by quorum sensing (QS) in many bacteria. However, studies of the regulation of pigments produced by marine bacteria in saline conditions and of biofilm-associated phenotypes are scarcer. This study focuses on the demonstration of the existence of a QS communication system involving N-acylhomoserine lactones (AHLs) in the Mediterranean Sea strain Pseudoalteromonas ulvae TC14.

Antifouling coatings influence both abundance and community structure of colonizing biofilms: a case study in the Northwestern Mediterranean Sea.

When immersed in seawater, substrates are rapidly colonized by both micro- and macroorganisms. This process is responsible for important economic and ecological prejudices, particularly when related to ship hulls or aquaculture nets. Commercial antifouling coatings are supposed to reduce biofouling, i.

Identification of bacterial strains isolated from the Mediterranean Sea exhibiting different abilities of biofilm formation.

The Mediterranean Sea has rarely been investigated for the characterization of marine bacteria as compared to other marine environments such as the Atlantic or Pacific Ocean. Bacteria recovered from inert surfaces are poorly studied in these environments, when it has been shown that the community structure of attached bacteria can be dissimilar from that of planktonic bacteria present in the water column. The objectives of this study were to identify and characterize marine bacteria isolated from biofilms developed on inert surfaces immersed in the Mediterranean Sea and to evaluate their capacity to form a biofilm in vitro.

Protective effects of ethyl acetate fraction of Lawsonia inermis fruits extract against carbon tetrachloride-induced oxidative damage in rat liver.

This study aimed to investigate the antioxidant properties of different fractions obtained from the fruits of Lawsonia inermis, a widely used medicinal plant, against carbon tetrachloride (CCl4)-induced oxidative stress in rat liver. The results show that several fractions obtained from L. inermis fruits possessed important antioxidant activity.

Marine biofilms on artificial surfaces: structure and dynamics.

The search for new antifouling (AF) coatings that are environmentally benign has led to renewed interest in the ways that micro-organisms colonize substrates in the marine environment. This review covers recently published research on the global species composition and dynamics of marine biofilms, consisting mainly of bacteria and diatoms found on man-made surfaces including AF coatings. Marine biofilms directly interact with larger organisms (macrofoulers) during colonization processes; hence, recent literature on understanding the basis of the biofilm/macrofouling interactions is essential and will also be reviewed here.

Correlation between synthesis variation of 2-alkylquinolones and the antifungal activity of a Burkholderia cepacia strain collection.

Twenty epiphytic and rhizospheric bacterial strains harbouring strong antifungal activities were isolated from the Tunisian environment. This group of bacteria was identified as Burkholderia cepacia genomovar I using 16S rDNA and recA fragment gene sequence analyses for two selected strains and RFLP technique for the eighteen other ones. This identification did not show variability between isolates despite the significant differences in the antifungal activities of their culture supernatant and the organic crude extract against Aspergillus niger and other phytopathogenic fungi.

Pioneer marine biofilms on artificial surfaces including antifouling coatings immersed in two contrasting French Mediterranean coast sites.

Marine biofilm communities that developed on artificial substrata were investigated using molecular and microscopic approaches. Polystyrene, Teflon® and four antifouling (AF) paints were immersed for 2 weeks at two contrasting sites near Toulon on the French Mediterranean coast (Toulon military harbour and the natural protected area of Porquerolles Island). Biofilms comprising bacteria and diatoms were detected on all the coatings.

Synthesis, cytotoxicity and structure-activity relationships between ester and amide functionalities in novel acridine-based platinum(II) complexes.

In order to improve the pharmacological profile of the anticancer drug cisplatin, several new acridine-based tethered (ethane-1,2-diamine)platinum(II) complexes connected by a polymethylene chain were synthetized. Activity-structure relationship between amide or ester functionalities was explored by changing acridine-9-carboxamide into acridine-9-carboxylate chromophore. The in vitro cytotoxicity of these new complexes was assessed in human colic HCT 116, SW480 and HT-29 cancer cell lines.

Antifouling properties of simple indole and purine alkaloids from the Mediterranean gorgonian Paramuricea clavata.

Chemical investigation of the Mediterranean gorgonian Paramuricea clavata resulted in the isolation of two new alkaloids, 2-bromo-N-methyltryptamine (1) and 3-bromo-N-methyltyramine (2), together with nine known compounds (3-10 and linderazulene). The bromoindole derivative 3 is reported herein for the first time from a natural source. The chemical structures of these compounds were assigned by spectroscopic analyses and comparison with literature values.

Antifouling activity of commercial biocides vs. natural and natural-derived products assessed by marine bacteria adhesion bioassay.

Biofilm formation is a key step during marine biofouling, the natural colonization of immersed substrata, leading to major economic and ecological consequences. Consequently, bacteria have been used for the screening of new non-toxic antifoulants: the adhesion of five strains isolated on three French locations was monitored using a fluorescence-based assay and toxicity was also evaluated. Nine biocides including commercial, natural and natural-derived products were tested.

Environmental Burkholderia cepacia strain Cs5 acting by two analogous alkyl-quinolones and a didecyl-phthalate against a broad spectrum of phytopathogens fungi.

An environmental Burkholderia cepacia strain named Cs5 was isolated and identified first using API biochemical identification system and then with 16S rDNA and recA sequence homology search. This bacterium exhibited a broad spectrum of fungicidal activities against Alternaria alternata, Aspergillus niger, Fusarium culmorum, F. graminearum, F.

Targeting bacterial biofilms: design of a terpenoid-like library as non-toxic anti-biofilm compounds.

A new class of anti-biofilm compounds possessing 1,4-disubstituted-(1H)-1,2,3-triazolic cores was designed. Their efficient synthesis was performed by means of click chemistry through 1,3-dipolar cycloadditions. Two compounds were found to act as specific anti-biofilm agents against a gram negative species.

Antifungal activities of an endophytic Pseudomonas fluorescens strain Pf1TZ harbouring genes from pyoluteorin and phenazine clusters.

Pseudomonas fluorescens Pf1TZ was inhibitory in vitro to a number of phytopathogenic fungi and could protect vine plantlets against Botrytis cinerea. Total protection was reached after 3 weeks of bacterial inoculation. The endophytism of Pf1TZ was confirmed by confocal microscopy using its inherent fluorescence.

Design and preparation of aza-analogues of benzo[c]phenanthridine framework with cytotoxic and antiplasmodial activities.

Benzo[c]phenanthridine alkaloids represent interesting lead for the discovery of new potential antiplasmodial and/or anticancer drugs. In this field, a novel library of aza-analogs of benzo[c]phenanthroline framework derivatives was designed and prepared. Although these compounds did not have specific antiplasmodial activities, some of them displayed specific in vitro activity against two cancer lines especially compound 24 with an IC(50) against the MCF7 line of 0.

Diterpenoids from the Mediterranean brown alga Dictyota sp. evaluated as antifouling substances against a marine bacterial biofilm.

Four new cyclized diterpenes, one xenicane (1) and three dolabellanes (2-4), were isolated, along with seven previously reported metabolites [3beta-hydroxydilophol (5), dictyols E (6) and C (7), hydroxycrenulide (8), 9-acetoxy-15-hydroxy-1,6-dollabelladiene (9), hydroxyacetyldictyolal (10), and fucoxanthin], from a Mediterranean species of Dictyota sp. collected in Le Brusc Lagoon (French Mediterranean coast). Their structures, as well as their relative configurations, were determined through extensive spectrometric (IR, HRESIMS, 1D and 2D NMR) data analysis and molecular modeling studies and by comparison with those reported in literature.

Design, synthesis and preliminary biological evaluation of acridine compounds as potential agents for a combined targeted chemo-radionuclide therapy approach to melanoma.

Various iodo-acridone and acridine carboxamides have been prepared and evaluated as agents for targeted radionuclide and/or chemotherapy for melanoma, due to their structural similarity to benzamides which are known to possess specific affinity for melanin. Three of these carboxamides selected for their in vitro cytotoxic properties were radioiodinated with [(125)I]NaI at high specific activity. Biodistribution studies carried out in B16F0 murine melanoma tumour-bearing mice highlighted that acridone 8f and acridine 9d, presented high, long-lasting tumour concentrations together with an in vivo kinetic profile favourable to application in targeted radionuclide therapy.

Design, synthesis, and biological activities of conformationally restricted analogs of primaquine with a 1,10-phenanthroline framework.

A series of primaquine analogs was prepared, according to a conformationally restricted conformation of primaquine. In vitro antiplasmodial activities were evaluated and showed that all compounds were active on different strains of Plasmodium falciparum. In particular compounds 5 and 15 possessing a methoxy group were more active than was primaquine.

Synthesis and biological evaluation of indoloquinolines and pyridocarbazoles: a new example of unexpected photoreduction accompanying photocyclization.

Indoloquinoline alkaloid cryptolepine and pyridocarbazole alkaloid ellipticine are of great interest because in vitro and in vivo studies revealed their good cytotoxic properties. In order to obtain some biologically active analogs of these compounds, we developed a synthesis based on the photocyclization of tertiary N-substituted enaminones derived from 1,3-cyclohexandione and 3 or 6-aminoquinoline. The angular cyclized compounds thus obtained were tested in vitro on K 562 cells and A 2780 doxorubicin sensitive and resistant cells.

In vitro and in vivo antimalarial activity of derivatives of 1,10-phenanthroline framework.

A series of trisubstituted 1,10-phenanthrolines was prepared. These compounds exhibited mild to high biological activities in vitro both toward chloroquino-resistant FcB1-Columbia and FcM29-Cameron strains and Nigerian chloroquino-sensitive strain of Plasmodium falciparum. Cytotoxicity of the most active compounds was estimated showing that one compound (10) exhibited a selective activity against malaria parasite (selectivity indexes of 52 and 144).