Microbes and Persistent Organic Pollutants in the Marine Environment

Marine pollution has increased reaching the entire marine environment, from the surface to the deepest sediment, and has become more concerning in the last 70 years. Persistent organic pollutants (POPs) are a fraction of ocean waste that includes, among the others, polycyclic aromatic hydrocarbons (PAHs) and plastic polymers. These chemicals have an extremely long half-life, and (bio)accumulate and damage the marine flora and fauna, and, ultimately, human health. Some organisms have evolved enzymes to attack POPs in the environment and transform them into biomass and CO2. Several microorganisms degrade many POPs in relatively short time. A wide variety of bacteria has been isolated with different techniques, and key catabolic enzymes used to degrade the most persistent oil hydrocarbon fractions have been identified. For plastic waste, there is less evidence of microbial degradation, but a few recent studies are revealing that a biodegradation potential exists for some of the most recalcitrant plastic polymers as well. The scientific community is focusing on microorganisms and their enzymes for POP uptake and removal from the environment, while searching novel biopolymers (also from microbiological origin) to substitute oil-derived plastics

A modified culture medium for improved isolation of marine vibrios

Marine Vibrio members are of great interest for both ecological and biotechnological research, which often relies on their isolation. Whereas many efforts have been made for the detection of food-borne pathogenic species, much less is known about the performances of standard culture media toward environmental vibrios. We show that the isolation/enumeration of marine vibrios using thiosulfate-citrate-bile salts-sucrose agar (TCBS) as selective medium may be hampered by the variable adaptability of different taxa to the medium, which may result even in isolation failure and/or in substantial total count underestimation. We propose a modified TCBS as isolation medium, adjusted for marine vibrios requirements, which greatly improved their recovery in dilution plate counts, compared with the standard medium. The modified medium offers substantial advantages over TCBS, providing more accurate and likely estimations of the actual presence of vibrios. Modified TCBS allowed the recovery of otherwise undetected vibrios, some of which producing biotechnologically valuable enzymes, thus expanding the isolation power toward potentially new enzyme-producers Vibrio taxa. Moreover, we report a newly designed Vibrio-specific PCR primers pair, targeting a unique rpoD sequence, useful for rapid confirmation of isolates as Vibrio members and subsequent genetic analyses

Comparative Genomics Analysis of a New Exiguobacterium Strain from Salar de Huasco Reveals a Repertoire of Stress-Related Genes and Arsenic Resistance

Indexación: Web of Science; Scopus.The Atacama Desert hosts diverse ecosystems including salt flats and shallow Andean lakes. Several heavy metals are found in the Atacama Desert, and microorganisms growing in this environment show varying levels of resistance/tolerance to copper, tellurium, and arsenic, among others. Herein, we report the genome sequence and comparative genomic analysis of a new Exiguobacterium strain, sp. SH31, isolated from an altiplanic shallow athalassohaline lake. Exiguobacterium sp. SH31 belongs to the phylogenetic Group II and its closest relative is Exiguobacterium sp. S17, isolated from the Argentinian Altiplano (95% average nucleotide identity). Strain SH31 encodes a wide repertoire of proteins required for cadmium, copper, mercury, tellurium, chromium, and arsenic resistance. Of the 34 Exiguobacterium genomes that were inspected, only isolates SH31 and S17 encode the arsenic efflux pump Acr3. Strain SH31 was able to grow in up to 10 mM arsenite and 100 mM arsenate, indicating that it is arsenic resistant. Further, expression of the ars operon and acr3 was strongly induced in response to both toxics, suggesting that the arsenic efflux pump Acr3 mediates arsenic resistance in Exiguobacterium sp. SH31.http://journal.frontiersin.org/article/10.3389/fmicb.2017.00456/ful

Isolation and Characterization of Oil-Degrading Bacteria from Bilge Water

Twenty-one oil-degrading bacteria were isolated from bilge water. Based on a high growth rate on crude oil and on hydrocarbon degradation ability, 7 strains were selected (from 21 isolated) for further studies. 16S rRNA gene sequencing showed that isolated strains were affiliated to Bacillus, Pseudomonas and Halomonas genera; in particular, isolate BW-B12 (Bacillus sp., 99%), BW-C12 (Halomonas boliviensis, 99%) and BW-E12 (Halomonas boliviensis, 98%) were the best crude-oil degraders; after 10 days of cultivation in ONR 7a mineral medium supplemented with crude oil as single carbon source BW-B12, BW-C12 and BW-E12 showed a degradation rate of 80, 60 and 59%, respectively. The strains showed also a high emulsification activity and biosurfactants production. Obtained results give an important contribution in order to utilize these bilge water autochthonous microorganisms in processes of bioremediation of marine environment chronically polluted from saline oily wast

Bacterial biofilms on biopolymeric sorbent supports for environmental bioremediation

Bioremediation encompasses a broad range of environmental biotechnology, which require multidisciplinary approaches through implementation of innovative tools to the natural biological process occurring in soil, water and air. Immobilization of hydrocarbon-degrading microorganisms on biodegradable sorbent supports significantly promotes bioremediation processes. Recently ecofriendly, low cost bioremediation devices based on polylactic acid (PLA) and polycaprolactone (PCL) membranes hosting a biodegrading bacterial biofilms were obtained[1]. This work investigates the higher effectiveness of immobilizing hydrocarbon-degrading bacteria compared to that of planktonic cells. Soil hydrocarbon (HC) degrading Actinobacteria Nocardia cyriacigeorgica strain SoB, Gordonia amicalis strain SoCg[2], and the marine hydrocarbonoclastic Alcanivorax borkumensis strain AU3-AA-7[3] were immobilized on PLA and PCL membranes and tested on hexadecane. The capacity of adhesion and proliferation of these biodegrading biofilms within the biopolymers were evaluated at various time points (5, 10, 15, and 30 incubation days) using scanning electron microscopy (SEM). The SEM images revealed that PLA and PCL nanofibers were nearly completely covered by a complex three-dimensional bacterial film for all tested strains. Quantification of total biomass (estimated as total dsDNA) confirmed biofilm growth up to 30 days of incubation. Crude oil biodegradation ability of biofilms-membranes systems, assessed by Gas Chromatography-FID analysis, demonstrated the removal of over 60% of the oil after 5 days of incubation, outperforming free-living bacteria by 24%. Viable plate counts showed that bacterial biofilms adsorbed on biopolymers were still viable after 30 days, indicating their potential for long-term applications

Innate immune activating ligand SUMOylation affects tumor cell recognition by NK cells

Natural Killer cells are innate lymphocytes involved in tumor immunosurveillance. They express activating receptors able to recognize self-molecules poorly expressed on healthy cells but up-regulated upon stress conditions, including transformation. Regulation of ligand expression in tumor cells mainly relays on transcriptional mechanisms, while the involvement of ubiquitin or ubiquitin-like modifiers remains largely unexplored. Here, we focused on the SUMO pathway and demonstrated that the ligand of DNAM1 activating receptor, PVR, undergoes SUMOylation in multiple myeloma. Concurrently, we found that PVR is preferentially located in intracellular compartments in human multiple myeloma cell lines and malignant plasma cells and that inhibition of the SUMO pathway promotes its translocation to the cell surface, increasing tumor cell susceptibility to NK cell-mediated cytolysis. Our findings provide the first evidence of an innate immune activating ligand regulated by SUMOylation, and confer to this modification a novel role in impairing recognition and killing of tumor cells.Natural Killer cells are innate lymphocytes involved in tumor immunosurveillance. They express activating receptors able to recognize self-molecules poorly expressed on healthy cells but up-regulated upon stress conditions, including transformation. Regulation of ligand expression in tumor cells mainly relays on transcriptional mechanisms, while the involvement of ubiquitin or ubiquitin-like modifiers remains largely unexplored. Here, we focused on the SUMO pathway and demonstrated that the ligand of DNAM1 activating receptor, PVR, undergoes SUMOylation in multiple myeloma. Concurrently, we found that PVR is preferentially located in intracellular compartments in human multiple myeloma cell lines and malignant plasma cells and that inhibition of the SUMO pathway promotes its translocation to the cell surface, increasing tumor cell susceptibility to NK cell-mediated cytolysis. Our findings provide the first evidence of an innate immune activating ligand regulated by SUMOylation, and confer to this modification a novel role in impairing recognition and killing of tumor cells

Comparison of different primer sets for use in automated ribosomal intergenic spacer analysis of complex bacterial communities

ITSF and ITSReub, constituting a new primer set designed for the amplification of the 16S-23S rRNA intergenic transcribed spacers, have been compared with primer sets consisting of 1406F and 23Sr (M. M. Fisher and E. W. Triplett, Appl. Environ. Microbiol. 65:4630-4636, 1999) and S-D-Bact-1522-b-S-20 and L-D-Bact-132-a-A-18 (L. Ranjard et al., Appl. Environ. Microbiol. 67:4479-4487, 2001), previously proposed for automated ribosomal intergenic spacer analysis (ARISA) of complex bacterial communities. An agricultural soil and a polluted soil, maize silage, goat milk, a small marble sample from the fac\ub8ade of the Certosa of Pavia (Pavia, Italy), and brine from a deep hypersaline anoxic basin in the Mediterranean Sea were analyzed with the three primer sets. The number of peaks in the ARISA profiles, the range of peak size (width of the profile), and the reproducibility of results were used as indices to evaluate the efficiency of the three primer sets. The overall data showed that ITSF and ITSReub generated the most informative (in term of peak number) and reproducible profiles and yielded a wider range of spacer sizes (134 to 1,387) than the other primer sets, which were limited in detecting long fragments. The minimum amount of DNA template and sensitivity in detection of minor DNA populations were evaluated with artificial mixtures of defined bacterial species. ITSF and ITSReub amplified all the bacteria at DNA template concentrations from 280 to 0.14 ng l 1, while the other primer sets failed to detect the spacers of one or more bacterial strains. Although the primer set consisting of ITSF and ITSReub and that of S-D-Bact-1522-b-S-20 and L-D-Bact-132-a-A-18 showed similar sensitivities for the DNA of Allorhizobium undicula mixed with the DNA of other species, the S-D-Bact-1522-b-S-20 and L-D-Bact-132-a-A-18 primer set failed to detect the DNA of Pseudomonas stutzeri

The ferric iron uptake regulator (Fur) from the extreme acidophile Acidithiobacillus ferrooxidans

Indexación: Scopus.Acidithiobacillus ferrooxidans is a Gram-negative bacterium that lives at pH 2 in high concentrations of soluble ferrous and ferric iron, making it an interesting model for understanding the biological mechanisms of bacterial iron uptake and homeostasis in extremely acid conditions. A candidate furAF (Ferric Uptake Regulator) gene was identified in the A. ferrooxidans ATCC 23270 genome. FurAF has significant sequence similarity, including conservation of functional motifs, to known Fur orthologues and exhibits cross-reactivity to Escherichia coli Fur antiserum. The furAF gene is able to complement fur deficiency in E. coli in an iron-responsive manner. FurAF is also able to bind specifically to E. coli Fur regulatory regions (Fur boxes) and to a candidate Fur box from A. ferrooxidans, as judged by electrophoretic mobility shift assays. FurAF represses gene expression from E. coli Fur-responsive promoters fiu and fhuF when expressed at high protein levels. However, it increases gene expression from these promoters at low concentrations and possibly from other Fur-regulated promoters involved in iron-responsive oxidative stress respon.https://www.microbiologyresearch.org/content/journal/micro/10.1099/mic.0.27581-

B-type natriuretic peptide levels predict extent and severity of coronary disease in non-ST elevation coronary syndromes and normal left ventricular systolic function.

BACKGROUND: B-type natriuretic peptide (BNP) has been used recently as a biological marker in patients with coronary artery disease (CAD) with ST-elevation, as well as without ST-elevation. BNP is able to predict systolic dysfunction, adding new prognostic information to existing traditional markers. However is not known if there is a relation between the quantity of BNP levels and the severity of coronary artery disease. METHODS: This study compared B-type natriuretic peptide (BNP) levels in patients with stable angina (SA) and acute coronary syndromes (ACS) without ST-elevation in relation to angiographic lesions using TIMI and Gensini Scores. We studied 282 patients with CAD without ST elevation and preserved systolic function. BNP samples were measured in all recruited patients within 24 hours of hospitalization. RESULTS: BNP values were progressively increased in relation to the severity of diagnosis: SA (52.6±49.4 pg/mL ) UA (243.3±212 pg/mL) NSTE-ACS (421.7±334 pg/mL) (p<0.0001 and p<0.007 respectively). No statistically significant difference was observed between patients with SA and controls (21.2±6.8 pg/mL). The analysis of BNP levels in relation to the number of involved vessels demonstrated significantly increased levels in patients with multivessel disease compared to patients with 1 or 2 vessel disease (1-86.2±46.3 pg/mL; 2-127±297 pg/mL; 3-295±318 pg/mL; 4-297±347 pg/mL p<0.001 and p<0.003). Evaluation of BNP using Gensini Score showed a strong relation between BNP and coronary disease extension (r=0.38 p<0.0001).This trend was maintained in all CAD groups (SA=r 0.54; UA r=0.36 NSTE-ACS r=0.28). CONCLUSIONS: Circulating BNP levels appear elevated in ACS with diffuse coronary involvement, even in the absence of systolic dysfunction. BNP is also associated with multi-vessel disease and the extension of coronary disease

Hydrogen and Carbon Monoxide-Utilizing Kyrpidia spormannii Species From Pantelleria Island, Italy

Volcanic and geothermal areas are hot and often acidic environments that emit geothermal gasses, including H2, CO and CO2. Geothermal gasses mix with air, creating conditions where thermoacidophilic aerobic H2- and CO-oxidizing microorganisms could thrive. Here, we describe the isolation of two Kyrpidia spormannii strains, which can grow autotrophically by oxidizing H2 and CO with oxygen. These strains, FAVT5 and COOX1, were isolated from the geothermal soils of the Favara Grande on Pantelleria Island, Italy. Extended physiology studies were performed with K. spormannii FAVT5, and showed that this strain grows optimally at 55\ub0C and pH 5.0. The highest growth rate is obtained using H2 as energy source (\u3bcmax 0.19 \ub1 0.02 h\u20131, doubling time 3.6 h). K. spormannii FAVT5 can additionally grow on a variety of organic substrates, including some alcohols, volatile fatty acids and amino acids. The genome of each strain encodes for two O2-tolerant hydrogenases belonging to [NiFe] group 2a hydrogenases and transcriptome studies using K. spormannii FAVT5 showed that both hydrogenases are expressed under H2 limiting conditions. So far no Firmicutes except K. spormannii FAVT5 have been reported to exhibit a high affinity for H2, with a Ks of 327 \ub1 24 nM. The genomes of each strain encode for one putative CO dehydrogenase, belonging to Form II aerobic CO dehydrogenases. The genomic potential and physiological properties of these Kyrpidia strains seem to be quite well adapted to thrive in the harsh environmental volcanic conditions