Exopolysaccharide ID1 Improves Post-Warming Outcomes after Vitrification of In Vitro-Produced Bovine Embryos.

This study aimed to assess the cryoprotectant role of exopolysaccharide (EPS) ID1, produced by Antarctic sp., in the vitrification of in vitro-produced (IVP) bovine embryos. IVP day 7 (D7) and day 8 (D8) expanded blastocysts derived from cow or calf oocytes were vitrified without supplementation (EPS0) or supplemented with 10 µg/mL (EPS10) or 100 µg/mL (EPS100) EPS ID1.

Cryoprotectant role of exopolysaccharide ID1 in the vitrification/in-straw warming of in vitro-produced bovine embryos.

The cold-adapted bacterium Pseudomonas sp. ID1 produces the extracellular exopolysaccharide ID1 (EPS ID1) with cryoprotective activity. This study was designed to optimize the vitrification/in-straw warming protocol of in vitro-produced (IVP) blastocysts by adding EPS ID1 to the vitrification media.

Phage-Mediated Explosive Cell Lysis Induces the Formation of a Different Type of O-IMV in M7.

M7 is a cold-adapted Antarctic bacterium that has a great capacity to secrete membrane vesicles (MVs), making it a potentially excellent model for studying the vesiculation process. M7 undergoes a blebbing mechanism to produce different types of MVs, including outer membrane vesicles and outer-inner membrane vesicles (O-IMVs). More recently, other mechanisms have been considered that could lead to the formation of O-IMVs derived from prophage-mediated explosive cell lysis in other bacteria, but it is not clear if they are of the same type.

RNA release via membrane vesicles in Pseudomonas aeruginosa PAO1 is associated with the growth phase.

Pseudomonas aeruginosa PAO1 membrane vesicles (MVs) are known to play a role in cell-to-cell communication. Several studies have shown that the MV composition and physicochemical properties vary according to the bacterial growth stage, but the impact this might have on the externalization of RNA via MVs has not been addressed. Therefore, a study to characterize the RNA content from MVs retrieved at different growth phases was conducted.

Relationship Between Membrane Vesicles, Extracellular ATP and Biofilm Formation in Antarctic Gram-Negative Bacteria.

Biofilms offer a safe environment that favors bacterial survival; for this reason, most pathogenic and environmental bacteria live integrated in biofilm communities. The development of biofilms is complex and involves many factors, which need to be studied in order to understand bacterial behavior and control biofilm formation when necessary. We used a collection of cold-adapted Antarctic Gram-negative bacteria to study whether their ability to form biofilms is associated with a capacity to produce membrane vesicles and secrete extracellular ATP.

Cryo-transmission Electron Microscopy of Outer-inner Membrane Vesicles Naturally Secreted by Gram-negative Pathogenic Bacteria.

A protocol was developed to visualize and analyze the structure of membrane vesicles (MVs) from Gram-negative bacteria. It is now accepted that these micrometric spherical vesicles are commonly produced by cells from all three domains of life, so the protocol could be useful in the study of vesicles produced by eukaryotes and archaea as well as bacteria. The multiplicity of functions performed by MVs, related to cell communication, interaction with the immune system, pathogenesis, and nutrient acquisition, among others, has made MVs a hot topic of research.

Cryoprotectant role of exopolysaccharide of Pseudomonas sp. ID1 in the vitrification of IVM cow oocytes.

Biological molecules isolated from organisms that live under subzero conditions could be used to protect oocytes from cryoinjuries suffered during cryopreservation. This study examined the cryoprotectant role of exopolysaccharides of Pseudomonas sp. ID1 (EPS ID1) in the vitrification of prepubertal and adult cow oocytes.

Author Correction: DSYB catalyses the key step of dimethylsulfoniopropionate biosynthesis in many phytoplankton.

In the version of this Letter originally published, the Methods incorrectly stated that all phytoplankton cultures were sampled in mid-exponential phase. The low-nitrogen cultures were sampled in early stationary phase and at the point at which Fv/Fm values decreased, to indicate that cultures were experiencing low-nitrogen conditions. All other phytoplankton cultures were sampled in exponential phase.

DSYB catalyses the key step of dimethylsulfoniopropionate biosynthesis in many phytoplankton.

Dimethylsulfoniopropionate (DMSP) is a globally important organosulfur molecule and the major precursor for dimethyl sulfide. These compounds are important info-chemicals, key nutrients for marine microorganisms, and are involved in global sulfur cycling, atmospheric chemistry and cloud formation. DMSP production was thought to be confined to eukaryotes, but heterotrophic bacteria can also produce DMSP through the pathway used by most phytoplankton , and the DsyB enzyme catalysing the key step of this pathway in bacteria was recently identified .

Membrane Vesicles Released by a hypervesiculating Escherichia coli Nissle 1917 tolR Mutant Are Highly Heterogeneous and Show Reduced Capacity for Epithelial Cell Interaction and Entry.

Membrane vesicles (MVs) produced by Gram-negative bacteria are being explored for novel clinical applications due to their ability to deliver active molecules to distant host cells, where they can exert immunomodulatory properties. MVs released by the probiotic Escherichia coli Nissle 1917 (EcN) are good candidates for testing such applications. However, a drawback for such studies is the low level of MV isolation from in vitro culture supernatants, which may be overcome by the use of mutants in cell envelope proteins that yield a hypervesiculation phenotype.

Cryo-electron tomography of plunge-frozen whole bacteria and vitreous sections to analyze the recently described bacterial cytoplasmic structure, the Stack.

Cryo-electron tomography (CET) of plunge-frozen whole bacteria and vitreous sections (CETOVIS) were used to revise and expand the structural knowledge of the "Stack", a recently described cytoplasmic structure in the Antarctic bacterium Pseudomonas deceptionensis M1(T). The advantages of both techniques can be complementarily combined to obtain more reliable insights into cells and their components with three-dimensional imaging at different resolutions. Cryo-electron microscopy (Cryo-EM) and CET of frozen-hydrated P.

Outer-inner membrane vesicles naturally secreted by gram-negative pathogenic bacteria.

Outer-inner membrane vesicles (O-IMVs) were recently described as a new type of membrane vesicle secreted by the Antarctic bacterium Shewanella vesiculosa M7T. Their formation is characterized by the protrusion of both outer and plasma membranes, which pulls cytoplasmic components into the vesicles. To demonstrate that this is not a singular phenomenon in a bacterium occurring in an extreme environment, the identification of O-IMVs in pathogenic bacteria was undertaken.

New emulsifying and cryoprotective exopolysaccharide from Antarctic Pseudomonas sp. ID1.

Pseudomonas sp. ID1 is a cold-adapted bacterium isolated from a marine sediment sample collected from South Shetland Islands (Antarctica) that is noted for the highly mucous appearance of its colonies. In this work, we have characterized an exopolysaccharide (EPS) produced by this strain, which is mainly composed of glucose, galactose and fucose, and has a molecular mass higher than 2×10(6) Da.

Antimicrobial activity of Antarctic bryozoans: an ecological perspective with potential for clinical applications.

The antimicrobial activity of Antarctic bryozoans and the ecological functions of the chemical compounds involved remain largely unknown. To determine the significant ecological and applied antimicrobial effects, 16 ether and 16 butanol extracts obtained from 13 different bryozoan species were tested against six Antarctic (including Psychrobacter luti, Shewanella livingstonensis and 4 new isolated strains) and two bacterial strains from culture collections (Escherichia coli and Bacillus cereus). Results from the bioassays reveal that all ether extracts exhibited antimicrobial activity against some bacteria.

The stack: a new bacterial structure analyzed in the Antarctic bacterium Pseudomonas deceptionensis M1(T) by transmission electron microscopy and tomography.

In recent years, improvements in transmission electron microscopy (TEM) techniques and the use of tomography have provided a more accurate view of the complexity of the ultrastructure of prokaryotic cells. Cryoimmobilization of specimens by rapid cooling followed by freeze substitution (FS) and sectioning, freeze fracture (FF) and observation of replica, or cryoelectron microscopy of vitreous sections (CEMOVIS) now allow visualization of biological samples close to their native state, enabling us to refine our knowledge of already known bacterial structures and to discover new ones. Application of these techniques to the new Antarctic cold-adapted bacterium Pseudomonasdeceptionensis M1(T) has demonstrated the existence of a previously undescribed cytoplasmic structure that does not correspond to known bacterial inclusion bodies or membranous formations.

New type of outer membrane vesicle produced by the Gram-negative bacterium Shewanella vesiculosa M7T: implications for DNA content.

Outer membrane vesicles (OMVs) from Gram-negative bacteria are known to be involved in lateral DNA transfer, but the presence of DNA in these vesicles has remained difficult to explain. An ultrastructural study of the Antarctic psychrotolerant bacterium Shewanella vesiculosa M7(T) has revealed that this Gram-negative bacterium naturally releases conventional one-bilayer OMVs through a process in which the outer membrane is exfoliated and only the periplasm is entrapped, together with a more complex type of OMV, previously undescribed, which on formation drag along inner membrane and cytoplasmic content and can therefore also entrap DNA. These vesicles, with a double-bilayer structure and containing electron-dense material, were visualized by transmission electron microscopy (TEM) after high-pressure freezing and freeze-substitution (HPF-FS), and their DNA content was fluorometrically quantified as 1.

Pseudomonas deceptionensis sp. nov., a psychrotolerant bacterium from the Antarctic.

During the taxonomic investigation of cold-adapted bacteria from samples collected in the Antarctic area of the South Shetland Islands, one Gram-reaction-negative, psychrotolerant, aerobic bacterium, designated strain M1(T), was isolated from marine sediment collected on Deception Island. The organism was rod-shaped, catalase- and oxidase-positive and motile by means of a polar flagellum. This psychrotolerant strain grew at temperatures ranging from -4 °C to 34 °C.

Hyaluronidase expression by an oncolytic adenovirus enhances its intratumoral spread and suppresses tumor growth.

Successful virotherapy requires efficient virus spread within tumors. We tested whether the expression of hyaluronidase, an enzyme which dissociates the extracellular matrix (ECM), could enhance the intratumoral distribution of an oncolytic adenovirus and improve its therapeutic activity. As a proof of concept, we demonstrated that intratumoral coadministration of hyaluronidase in mice-bearing tumor xenografts improves the antitumor activity of an oncolytic adenovirus.

Membrane vesicles: a common feature in the extracellular matter of cold-adapted antarctic bacteria.

Many Gram-negative, cold-adapted bacteria from the Antarctic environment produce large amounts of extracellular matter, which has potential biotechnology applications. We examined the ultrastructure of extracellular matter from five Antarctic bacteria (Shewanella livingstonensis NF22(T), Shewanella vesiculosa M7(T), Pseudoalteromonas sp. M4.

Shewanella vesiculosa sp. nov., a psychrotolerant bacterium isolated from an Antarctic coastal area.

Two strains of psychrotolerant bacteria, designated M7(T) and M5, isolated from Antarctic coastal marine environments were studied to determine their taxonomic position. The organisms comprised Gram-negative, rod-shaped, facultatively anaerobic cells that were motile by means of single polar flagella. Neither of the bacterial isolates had a requirement for Na(+).

Adenoviral-mediated overexpression of human equilibrative nucleoside transporter 1 (hENT1) enhances gemcitabine response in human pancreatic cancer.

Nucleoside-derived anticancer agents must be transported across the plasma membrane as a preliminary step to their conversion into active drugs. Hence, modulation of a specific nucleoside transporter may affect bioavailability and contribute significantly to sensitizing tumor cells to these anticancer agents. We have generated and functionally characterized a new recombinant adenovirus (Ad-hENT1) that has allowed us to overexpress the equilibrative nucleoside transporter hENT1 and to analyze its effects in human pancreatic tumor cells.

Marinobacter guineae sp. nov., a novel moderately halophilic bacterium from an Antarctic environment.

Two Gram-negative, cold-adapted, moderately halophilic, aerobic bacteria, designated strains M3B(T) and M3T, were isolated from marine sediment collected from the South Shetland Islands, Antarctica. The organisms were rod-shaped, catalase- and oxidase-positive, and motile by means of polar flagella. These two psychrotolerant strains required Na(+) and grew at NaCl concentrations of 1-15 % and temperatures between 4 and 42 degrees C.

Pseudomonas guineae sp. nov., a novel psychrotolerant bacterium from an Antarctic environment.

Two Gram-negative, cold-adapted, aerobic bacteria, designated strains M8T and M6, were isolated from soil collected from the South Shetland Islands. The organisms were rod-shaped, catalase- and oxidase-positive and motile by means of polar flagella. These two psychrotolerant strains grew between -4 and 30 degrees C.

Characterization of outer membrane vesicles released by the psychrotolerant bacterium Pseudoalteromonas antarctica NF3.

Pseudoalteromonas antarctica NF3 is an Antarctic psychrotolerant Gram-negative bacterium that accumulates large amounts of an extracellular polymeric substance (EPS) with high protein content. Transmission electron microscopy analysis after high-pressure freezing and freeze substitution (HPF-FS) shows that the EPS is composed of a capsular polymer and large numbers of outer membrane vesicles (OMVs). These vesicles are bilayered structures and predominantly spherical in shape, with an average diameter of 25-70 nm, which is similar to what has been observed in OMVs from other Gram-negative bacteria.