Improved antioxidant capacity of three vegetables by two-step controlled fermentation using isolated autochthone strains of the genus spp. and spp.

The aim of this study was to determine the evolution of total phenolic content and antioxidant activity during controlled fermentation of three different Brassicaceae and compare it with spontaneous fermentations. The two-step controlled fermentation was carried out with lactic acid bacteria selected by their biotechnological properties. The selected bacteria were genotypically identified as ssp.

Utilization of Agro-Industrial Byproducts for Bacteriocin Production Using Enterococcus spp. Strains Isolated from Patagonian Marine Invertebrates.

This work's objective was to determine the antagonist activity of 11 Enterococcus spp. using industrial food wastes as a culture medium. The strains were isolated from invertebrates collected on the Argentinian Patagonia coast and selected by their high antibacterial activity.

Assessment of the bioprotective potential of lactic acid bacteria against Listeria monocytogenes in ground beef.

Lactic acid bacteria can be considered as natural biopreservative and good biotechnological alternative to food safety. In this study, the antilisterial compounds produced by Enterococcus isolates from the Patagonian environment and their effectiveness for the control of Listeria monocytogenes in a food model were studied. Enterococcus isolates whose cell-free supernatant presented activity against Listeria monocytogenes were identified and evaluated for their virulence factors.

Production and properties of a bioemulsifier obtained from a lactic acid bacterium.

In the present work, the production of bioemulsifier (BE) by a lactic acid bacterium (LAB) grown at 25 °C in lactic whey-based media for 24 h was evaluated. Maximum production was detected in a medium containing yeast extract, peptone and lactic whey (LAP medium), with a yield of 270 mg L. The BE proved to be more innocuous for Caco-2 cells, used as a toxicological indicator, than the non-ionic surfactant Triton X-100.

[Isolation of enterocin-producing Enterococcus hirae strains from the intestinal content of the Patagonian mussel (Mytilus edulis platensis)].

Two bacteriocin-producing lactic acid bacterial strains were isolated from the intestinal content of the Patagonian mussel and characterized by phenotypic and molecular tests. The isolates were identified as Enterococcus hirae and named E. hirae 463Me and 471Me.

Increase of positive supercoiling in a hyperthermophilic archaeon after UV irradiation.

Diverse DNA repair mechanisms are essential to all living organisms. Some of the most widespread repair systems allow recovery of genome integrity in the face of UV radiation. Here, we show that the hyperthermophilic archaeon Thermococcus nautili possesses a remarkable ability to recovery from extreme chromosomal damage.

Contribution of protein Gar1 to the RNA-guided and RNA-independent rRNA:Ψ-synthase activities of the archaeal Cbf5 protein.

Archaeal RNA:pseudouridine-synthase (PUS) Cbf5 in complex with proteins L7Ae, Nop10 and Gar1, and guide box H/ACA sRNAs forms ribonucleoprotein (RNP) catalysts that insure the conversion of uridines into pseudouridines (Ψs) in ribosomal RNAs (rRNAs). Nonetheless, in the absence of guide RNA, Cbf5 catalyzes the in vitro formation of Ψ in Pyrococcus abyssi 23S rRNA and of Ψ in tRNAs. Using gene-disrupted strains of the hyperthermophilic archaeon Thermococcus kodakarensis, we studied the in vivo contribution of proteins Nop10 and Gar1 to the dual RNA guide-dependent and RNA-independent activities of Cbf5 on 23S rRNA.

Flipping chromosomes in deep-sea archaea.

One of the major mechanisms driving the evolution of all organisms is genomic rearrangement. In hyperthermophilic Archaea of the order Thermococcales, large chromosomal inversions occur so frequently that even closely related genomes are difficult to align. Clearly not resulting from the native homologous recombination machinery, the causative agent of these inversions has remained elusive.

DJ-1 family Maillard deglycases prevent acrylamide formation.

The presence of acrylamide in food is a worldwide concern because it is carcinogenic, reprotoxic and neurotoxic. Acrylamide is generated in the Maillard reaction via condensation of reducing sugars and glyoxals arising from their decomposition, with asparagine, the amino acid forming the backbone of the acrylamide molecule. We reported recently the discovery of the Maillard deglycases (DJ-1/Park7 and its prokaryotic homologs) which degrade Maillard adducts formed between glyoxals and lysine or arginine amino groups, and prevent glycation damage in proteins.

Sulfur vesicles from Thermococcales: A possible role in sulfur detoxifying mechanisms.

The euryarchaeon Thermococcus prieurii inhabits deep-sea hydrothermal vents, one of the most extreme environments on Earth, which is reduced and enriched with heavy metals. Transmission electron microscopy and cryo-electron microscopy imaging of T. prieurii revealed the production of a plethora of diverse membrane vesicles (MVs) (from 50 nm to 400 nm), as is the case for other Thermococcales.

An abyssal mobilome: viruses, plasmids and vesicles from deep-sea hydrothermal vents.

Mobile genetic elements (MGEs) such as viruses, plasmids, vesicles, gene transfer agents (GTAs), transposons and transpovirions, which collectively represent the mobilome, interact with cellular organisms from all three domains of life, including those thriving in the most extreme environments. While efforts have been made to better understand deep-sea vent microbial ecology, our knowledge of the mobilome associated with prokaryotes inhabiting deep-sea hydrothermal vents remains limited. Here we focus on the abyssal mobilome by reviewing accumulating data on viruses, plasmids and vesicles associated with thermophilic and hyperthermophilic Bacteria and Archaea present in deep-sea hydrothermal vents.

Potential aquaculture probiont Lactococcus lactis TW34 produces nisin Z and inhibits the fish pathogen Lactococcus garvieae.

Bacteriocin-producing Lactococcus lactis TW34 was isolated from marine fish. TW34 bacteriocin inhibited the growth of the fish pathogen Lactococcus garvieae at 5 AU/ml (minimum inhibitory concentration), whereas the minimum bactericidal concentration was 10 AU/ml. Addition of TW34 bacteriocin to L.

Sakacin Q produced by Lactobacillus curvatus ACU-1: functionality characterization and antilisterial activity on cooked meat surface.

This work was conducted to evaluate the antilisterial activity of sakacin Q produced by Lactobacillus curvatus ACU-1 on the surface of cooked pork meat. A genetic re-characterization of the producer strain and a study of the structural genes involved in bacteriocin production were carried out as complementary data. Studies indicated that the bacteriocin was not attached to the producer cells favoring pre-purifications steps.

Genome Sequence of a Hyperthermophilic Archaeon, Thermococcus nautili 30-1, That Produces Viral Vesicles.

Thermococcus nautili 30-1 (formerly Thermococcus nautilus), an anaerobic hyperthermophilic marine archaeon, was isolated in 1999 from a deep-sea hydrothermal vent during the Amistad campaign. Here, we present the complete sequence of T. nautili, which is able to produce membrane vesicles containing plasmid DNA.

Thermococcus nautili sp. nov., a hyperthermophilic archaeon isolated from a hydrothermal deep-sea vent.

Thermococcus nautili, strain 30-1T (formerly reported as Thermococcus nautilus), was isolated from a hydrothermal chimney sample collected from the East Pacific Rise at a depth of 2633 m on the 'La chainette PP57' area. Cells were motile, irregular cocci with a polar tuft of flagella (0.8-1.

Extracellular membrane vesicles harbouring viral genomes.

Cells from the three domains of life produce extracellular membrane vesicles (MVs), suggesting that MV production is a fundamental aspect of cellular physiology. We have recently shown that MVs produced by the hyperthermophilic archaeon Thermococcus kodakaraensis can be used as vehicles to transfer exogenous recombinant plasmid DNA from cell to cell. Here, we show that Thermococcus nautilus, which harbours three plasmids, pTN1, pTN2 and pTN3, produces MVs, and that some of them selectively incorporate pTN1 and pTN3.

Hyperthermophilic archaea produce membrane vesicles that can transfer DNA.

Thermococcales are hyperthermophilic archaea found in deep-sea hydrothermal vents. They have been recently reported to produce membrane vesicles (MVs) into their culture medium. Here, we have characterized the mode of production and determined the biochemical composition of MVs from two species of Thermococcales, Thermococcus gammatolerans and Thermococcus kodakaraensis.

Membrane vesicles, nanopods and/or nanotubes produced by hyperthermophilic archaea of the genus Thermococcus.

Thermococcus species produce MVs (membrane vesicles) into their culture medium. These MVs are formed by a budding process from the cell envelope, similar to ectosome formation in eukaryotic cells. The major protein present in MVs of Thermococci is a peptide-binding receptor of the OppA (oligopeptide-binding protein A) family.

Fake virus particles generated by fluorescence microscopy.

Many laboratories are actively studying the abundance and roles of viruses in natural ecosystems. In these studies, the presence and number of viral particles is usually determined using fluorescent dyes. However, DNA associated with membrane-derived vesicles (MVs), gene transfer agents (GTAs), or cell debris can produce fluorescent dots that can be confused with viral particles.

Plasmids, viruses and virus-like membrane vesicles from Thermococcales.

Several families of plasmids and viruses (PVs) have now been described in hyperthermophilic archaea of the order Thermococcales. One family of plasmids replicates by the rolling circle mechanism, whereas most other PVs probably replicate by the θ mode. PVs from Thermococcales encode novel families of DNA replication proteins that have only detectable homologues in other archaeal PVs.

Two novel families of plasmids from hyperthermophilic archaea encoding new families of replication proteins.

Thermococcales (phylum Euryarchaeota) are model organisms for physiological and molecular studies of hyperthermophiles. Here we describe three new plasmids from Thermococcales that could provide new tools and model systems for genetic and molecular studies in Archaea. The plasmids pTN2 from Thermococcus nautilus sp.

Inhibitory activity against the fish pathogen Lactococcus garvieae produced by Lactococcus lactis TW34, a lactic acid bacterium isolated from the intestinal tract of a Patagonian fish.

After enrichment of Odontesthes platensis intestinal contents, 53 lactic acid bacteria (LAB) were isolated. From the four isolates that showed inhibitory activity against Lactococcus garvieae 03/8460, strain TW34 was selected because it exerted the strongest inhibition. It also inhibited other Gram-positive bacteria, but not Gram-negative fish pathogens.

Virus-like vesicles and extracellular DNA produced by hyperthermophilic archaea of the order Thermococcales.

Cultures of hyperthermophilic archaea (order Thermococcales) have been analyzed by electron microscopy and epifluorescence staining for the presence of virus-like particles. We found that most strains of Thermococcus and Pyrococcus produce various types of spherical membrane vesicles and unusual filamentous structures. Cellular DNA can be strongly associated with vesicles and appears as fluorescent dots by epifluorescence microscopy, suggesting that some particles assumed to be viruses in ecological studies might instead be vesicles associated with extracellular DNA.