Taste Compounds and Polyphenolic Profile of Tomato Varieties Cultivated with Beneficial Microorganisms: A Chemical Investigation on Nutritional Properties and Sensory Qualities.

There is a strong need to develop eco-sustainable agricultural techniques to improve crop yields while preserving biomolecule contents and reducing the adverse environmental impact of agro-chemicals. The use of microorganisms in agriculture represents an attractive and innovative solution. Herein, a chemical study on the nutritional and sensory qualities of San Marzano Cirio 3 (SMC3), Corbarino (CO) and Brandywine (BW) tomato varieties cultivated with and without effective microorganisms (EM) is reported. LC-MS analysis of the methanolic extracts allowed for the identification of 21 polyphenol derivatives. In different proportions among the studied varieties, the two main polyphenols were rutin and naringenin chalcone; the latter was isolated and chemically identified by complementary HR-ESIMS/MS and NMR methods. SMC3 and CO were richer in naringenin chalcone. Conversely, BW showed higher proportions of rutin; however, in all cases, the relative amounts of the two polyphenols considered together increased over the other minor components after the EM treatment. The qualitative and quantitative HPLC analyses of taste-active compounds (aspartic acid, glutamic acid, AMP and GMP) revealed a significant difference in aspartic and glutamic acids and ribonucleotide contents according to the cultivation condition (±EM), particularly in BW. This study provides chemical data in support of the use of EM green technology for the cultivation of edible agricultural products, such as tomato preserves, and may even improve nutritional and sensory qualities while safeguarding the environment.

Research Progress and Hopeful Strategies of Application of Quorum Sensing in Food, Agriculture and Nanomedicine.

Quorum sensing (QS) regulates the expression of several genes including motility, biofilm development, virulence expression, population density detection and plasmid conjugation. It is based on "autoinducers", small molecules that microorganisms produce and release in the extracellular milieu. The biochemistry of quorum sensing is widely discussed and numerous papers are available to scientists. The main purpose of this research is to understand how knowledge about this mechanism can be exploited for the benefit of humans and the environment. Here, we report the most promising studies on QS and their resulting applications in different fields of global interest: food, agriculture and nanomedicine.

Nanoparticle treatment of maize analyzed through the metatranscriptome: compromised nitrogen cycling, possible phytopathogen selection, and plant hormesis.

BACKGROUND: The beneficial use of nanoparticle silver or nanosilver may be confounded when its potent antimicrobial properties impact non-target members of natural microbiomes such as those present in soil or the plant rhizosphere. Agricultural soils are a likely sink for nanosilver due to its presence in agrochemicals and land-applied biosolids, but a complete assessment of nanosilver's effects on this environment is lacking because the impact on the natural soil microbiome is not known. In a study assessing the use of nanosilver for phytopathogen control with maize, we analyzed the metatranscriptome of the maize rhizosphere and observed multiple unintended effects of exposure to 100 mg kg-1 nanosilver in soil during a growth period of 117 days. RESULTS: We found several unintended effects of nanosilver which could interfere with agricultural systems in the long term. Firstly, the archaea community was negatively impacted with a more than 30% decrease in relative abundance, and as such, their involvement in nitrogen cycling and specifically, nitrification, was compromised. Secondly, certain potentially phytopathogenic fungal groups showed significantly increased abundances, possibly due to the negative effects of nanosilver on bacteria exerting natural biocontrol against these fungi as indicated by negative interactions in a network analysis. Up to 5-fold increases in relative abundance have been observed for certain possibly phytopathogenic fungal genera. Lastly, nanosilver exposure also caused a direct physiological impact on maize as illustrated by increased transcript abundance of aquaporin and phytohormone genes, overall resulting in a stress level with the potential to yield hormetically stimulated plant root growth. CONCLUSIONS: This study indicates the occurrence of significant unintended effects of nanosilver use on corn, which could turn out to be negative to crop productivity and ecosystem health in the long term. We therefore highlight the need to include the microbiome when assessing the risk associated with nano-enabled agriculture. Video Abstract.

Extremophilic Natrinema versiforme Against Pseudomonas aeruginosa Quorum Sensing and Biofilm.

Pseudomonas aeruginosa is an opportunistic pathogen that causes high morbidity and mortality rates due to its biofilm form. Biofilm formation is regulated via quorum sensing (QS) mechanism and provides up to 1000 times more resistance against conventional antibiotics. QS related genes are expressed according to bacterial population density via signal molecules. QS inhibitors (QSIs) from natural sources are widely studied evaluating various extracts from extreme environments. It is suggested that extremely halophilic Archaea may also produce QSI compounds. For this purpose, we tested QS inhibitory potentials of ethyl acetate extracts from cell free supernatants and cells of Natrinema versiforme against QS and biofilm formation of P. aeruginosa. To observe QS inhibition, all extracts were tested on P. aeruginosa lasB-gfp, rhlA-gfp, and pqsA-gfp biosensor strains and biofilm inhibition was studied using P. aeruginosa PAO1. According to our results, QS inhibition ratios of cell free supernatant extract (CFSE) were higher than cell extract (CE) on las system, whereas CE was more effective on rhl system. In addition, anti-biofilm effect of CFSE was higher than CE. Structural analysis revealed that the most abundant compound in the extracts was trans 4-(2-carboxy-vinyl) benzoic acid.

Light-Responsive Nanocapsule-Coated Polymer Films for Antimicrobial Active Packaging.

The development of antimicrobial active packaging constitutes a powerful tool to reduce waste and increase quality standards of perishable goods. Among numerous available antimicrobial agents, essential oils stand out for their renowned efficiency, and their use is beneficial due to their sustainability compared to other oil-based antimicrobials. In this work, we report on the use of photo-responsive nanocapsules containing thyme essential oil as functional coatings for polyethylene and polylactic acid films to obtain antimicrobial active packaging. Polymer surface activation treatment enhanced compatibility with nanocapsules solution. The films were analyzed to assess the structural and functional properties of the coating, evaluate morphological changes due to their photo-responsive behavior, and monitor the light-induced release of volatile thyme oil. It was found that 24 h after a 15-min UV exposure of the coated films, the concentration of thyme oil in the headspace was eight times higher with respect to un-irradiated films, thus confirming the efficiency of the light-triggered release system. Therefore, the manufactured films are proposed as on-demand release devices for application in non-contact antimicrobial active packaging.

Antioxidant activity and bioactive compound contents before and after in vitro digestion of new tomato hybrids.

BACKGROUND: The antioxidant properties and bioactive compound contents of fresh new tomato hybrids before and after in vitro digestion were investigated. To this aim, the antioxidant activities of lipophilic, hydrophilic and polyphenolic extracts of tomato hybrids were determined by ABTS (2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid)), DMPD (N,N-dimethyl-p-phenylenediamine dihydrochloride) and DPPH (2,2-diphenyl-1-picrylhydrazyl) methods respectively, while the bioactive compound contents were estimated via Folin-Ciocalteu (polyphenols), pH differential (anthocyanins) and high-performance liquid chromatography (lycopene and ß-carotene) methods. RESULTS: After the digestion process, a marked loss (ranging from 37 to 77%) of antioxidant capacity linked to the hydrophilic fraction was observed. In contrast, the lipophilic and methanolic fractions showed an increase in antioxidant activity (ranging from 9 to 40%) after gastric digestion, and a rapid decrease was observed after total digestion. Moreover, the presence of anthocyanins and carotenoids after simulated digestion was a notable result. CONCLUSION: The bioavailability of bioactive metabolites from nutraceutical food and their healthful properties in humans are strictly dependent on the digestion process. © 2017 Society of Chemical Industry.

Draft Genome Sequence of Acinetobacter calcoaceticus Strain GK1, a Hydrocarbon-Degrading Plant Growth-Promoting Rhizospheric Bacterium.

The 3.94-Mb draft genome of Acinetobacter calcoaceticus GK1, a hydrocarbonoclastic plant growth-promoting Gram-negative rhizospheric bacterium, is presented here. Isolated at the Ford Motor Company site in Genk, Belgium, from poplar trees planted on a diesel-contaminated plume, GK1 is useful for enhancing hydrocarbon phytoremediation.

Effects of Industrial Processes on Antioxidant Power and Polyphenols Profile in Cherry Tomato Cultivar.

The antioxidant capacity and the polyphenolic profile of fresh and processed cherry tomatoes were analyzed with the aim of investigating the effect of industrial processes on the nutritional qualities of fruits. The results exhibited a decrease of antioxidant activity mainly in the lipophilic fraction of processed tomatoes compared with fresh products. No great difference in the antioxidant capacity was detected in the hydrophilic and methanolic extracts of fresh tomatoes and processed tomato juices. Moreover, a decrease of polyphenolic content, estimated by means of high-performance liquid chromatography analysis and Folin-Ciocalteu method, was observed in all tomato juices. The overall polyphenolic profile of both fresh and processed tomatoes did not change significantly and, among all juices, a higher polyphenolic content was detected in juice containing peels and seeds in comparison to those without. From our data on antioxidant power and the bioactive metabolite content, tomato juice could be used as a valid and easily available source of antioxidants in everyday diet to preserve human health.

Cyclic dipeptides produced by marine sponge-associated bacteria as quorum sensing signals.

Four bacterial strains belonging to the genera Vibrio, Pseudoalteromonas and Photobacterium were isolated from the marine sponges Dysidea avara and Geodia cynodium. A Bacillus strain was isolated from Ircinia variabilis. A screening of molecules involved in quorum sensing (QS) was carried out by TLC-overlay and a new "plate T-streak" test. To analyze quorum quenching (QQ), a plate T-streak was performed with Chromobacterium violaceum. Strains of Vibrio isolated from both marine sponges and a strain of Photobacterium isolated from G. cynodium, activated QS bioreporters. A strain of Pseudoalteromonas isolated from D. avara showed QQ activity. Finally, it is reported that cyclic dipeptides isolated from strains of Vibrio sp. and Bacillus sp. (isolated from D. avara and I. variabilis, respectively) were involved in the QS mechanism. The simultaneous presence of bacteria that showed contrasting responses in bioassays for QS signal molecule synthesis in marine sponges could add an interesting dimension to the signalling interactions which may be happening in sponges.

Antioxidant and cytotoxic activities investigation of tomato seed extracts.

Biological activities of different varieties of tomato seed extracts were evaluated to verify the potential antioxidant and/or antiproliferative activity of the bioactive metabolites present in them. Findings demonstrated that among all the varieties investigated (San Marzano Rosso, San Marzano Giallo, Corbarino, Black Tomato and San Marzano/Black Tomato hybrid) San Marzano Rosso seed extract exhibited the highest free radical-scavenging activity with 68% of 2,2-Diphenyl-1-picrylhydrazyl radical inhibition, and the best cytotoxic activity evaluated by using the brine shrimp test (LD50: 23,198 ppm) and 3-(4,5-dimethylthiazol-2-yl)-2,5-phenyl-2H-tetrazolium bromide assay on A375 cell line (IC50: 137.7 µg/mL).

Bioactivity of tomato hybrid powder: antioxidant compounds and their biological activities.

The antioxidant and cytotoxic activities and the polyphenolic and anthocyanin contents of tomato hybrid powders were studied. Tomato powders were obtained, starting from the fresh fruits that had undergone an industrial process of drying and pulverization at two different temperatures. Antioxidant activities were evaluated in different extracts by using spectrophotometric assays: 2,2'-azino-bis-(3-ethylbenzthiazoline-6-sulfonic acid and N,N-dimethyl-p-phenylenediamine dihydrochloride cation radical inhibition for lipophilic and hydrophilic extracts, respectively, and 2,2-diphenyl-1-picrylhydrazyl radical scavenging assay for polyphenolic extracts. Moreover, polyphenolic and anthocyanin contents were also carried out to detect the presence of these bioactive compounds. The effect of cytotoxic activity in vitro of tomato hybrid powder extracts on T47D (human breast carcinoma) cells was also evaluated. Results showed good antioxidant activities in lipophilic, polyphenolic, and hydrophilic extracts of samples that were obtained at a lower temperature. Extracts of the sample obtained at a higher temperature presented moderate antioxidant activity, lower than the extracts of other samples, which was probably due to the loss of labile antioxidant compounds during the industrial process. Very interesting was the presence of anthocyanins in both samples, even if in traces, and also a moderate cytotoxicity of a lipophilic extract on T47D cells. Therefore, tomato hybrid powders, on the basis of their multifunctional properties, could have a biotechnological application in agri-food or cosmetic industries as an additive for improving nutritional and/or bioactive qualities of commercial products used in daily nutrition and cosmetics.

Evaluation of antioxidant properties, total phenolic content, and biological activities of new tomato hybrids of industrial interest.

The objective of the present work was to establish the antioxidative ability linked to lipophilic, hydrophilic, and polyphenolic fractions of new tomato hybrids of industrial interest, grown in an outdoor field, named "Medugno", situated in the Agro-Nocerino Sarnese area (Province of Salerno, Campania Region, Italy). Antioxidant activities of lipophilic, hydrophilic, and polyphenolic extracts of tomato hybrids determined by the 2,2'-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid), N,N-dimethyl-p-phenylenediamine dihydrochloride, and 2,2-diphenyl-1-picrylhydrazyl methods, respectively, showed the best results in hybrids obtained between the pure San Marzano and Black Tomato lines. Antioxidant activity tests, performed also on the San Marzano × Black Tomato hybrid (pulped tomatoes), indicated that the industrial transformation process of this new tomato hybrid did not cause a significant loss of antioxidant activity. The in vitro production of nitrite by lipopolysaccharide-stimulated macrophages J774A.1 performed on lipophilic extracts showed that only two hybrids (San Marzano × Black Tomato and Marmande × Black Tomato) inhibited, in a concentration-related manner, nitric oxide release. Results suggested that genotypic factors could determine the nutritional quality of tomato because of the content of biologically active compounds and their biosynthesis. Moreover, the new tomato hybrid achieved could have a potential for the agri-food industry because of its nutritional quality and because it lends itself in processes of industrial transformation.

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.

Synthesis, production, and biotechnological applications of exopolysaccharides and polyhydroxyalkanoates by archaea.

Extreme environments, generally characterized by atypical temperatures, pH, pressure, salinity, toxicity, and radiation levels, are inhabited by various microorganisms specifically adapted to these particular conditions, called extremophiles. Among these, the microorganisms belonging to the Archaea domain are of significant biotechnological importance as their biopolymers possess unique properties that offer insights into their biology and evolution. Particular attention has been devoted to two main types of biopolymers produced by such peculiar microorganisms, that is, the extracellular polysaccharides (EPSs), considered as a protection against desiccation and predation, and the endocellular polyhydroxyalkanoates (PHAs) that provide an internal reserve of carbon and energy. Here, we report the composition, biosynthesis, and production of EPSs and PHAs by different archaeal species.