Search

The serum copper parameters were evaluated in 41 male trained runners and in a control group of 24 male subjects engaged in normal physical activity. In the runner group lower serum copper concentrations, lower serum ceruloplasmin biological activity, and higher serum ceruloplasmin levels were found compared with the control group. Reduced serum copper levels may affect the ceruloplasmin biological activity, even if the serum ceruloplasmin levels are higher. The results suggest that more attention should be paid to serum copper and ceruloplasmin in athletes.

Staphylococcus aureus is the major causative agent of skin and soft tissue infections, whose prevention and treatment have become more difficult due to the emergence of antibiotic-resistant strains. In this regard, the development of an effective treatment represents a challenge that can be overcome by delivering new antibiofilm agents with appropriate nanocarriers. In this study, a biosurfactant (BS) isolated from Lactobacillus gasseri BC9 and subsequently loaded in liposomes (LP), was evaluated for its ability to prevent the development and to eradicate the biofilm of different methicillin resistant S. aureus (MRSA) strains. BS from L. gasseri BC9 was not cytotoxic and was able to prevent formation and to eradicate the biofilm of different MRSA strains. BS loaded liposomes (BS-LP) presented a mean diameter (lower than 200 nm) suitable for topical administration and a low polydispersity index (lower than 0.2) that were maintained over time for up 28 days. Notably, BS-LP showed higher ability than free BS to inhibit S. aureus biofilm formation and eradication. BS-LP were loaded in lyophilized matrices able to quickly dissolve (dissolution time lower than 5 s) upon contact with exudate, thus allowing vesicle reconstitution. In conclusion, in this work, we demonstrated the antibiofilm activity of Lactobacillus-derived BS and BS-LP against clinically relevant MRSA strains. Furthermore, the affordable production of lyophilized matrices containing BS-LP for local prevention of cutaneous infections was established.

In an aquifer-aquitard system in the subsoil of the city of Ferrara (Emilia-Romagna region, northern Italy) highly contaminated with chlorinated aliphatic toxic organics such as trichloroethylene (TCE) and tetrachloroethylene (PCE), a strong microbial-dependent dechlorination activity takes place during migration of contaminants through shallow organic-rich layers with peat intercalations. The in situ microbial degradation of chlorinated ethenes, formerly inferredby the utilization of contaminant concentration profiles and Compound-Specific Isotope Analysis (CSIA), was here assessed using Illumina sequencing of V4 hypervariable region of 16S rRNA gene and by clone library analysis of dehalogenase metabolic genes. Taxon-specific investigation of the microbial communities catalyzing the chlorination process revealed the presence of not only dehalogenating genera such as Dehalococcoides and Dehalobacter but also of numerous other groups of non-dehalogenating bacteria and archaea thriving on diverse metabolisms such as hydrolysis and fermentation of complex organic matter, acidogenesis, acetogenesis, and methanogenesis, which can indirectly support the reductive dechlorination process. Besides, the diversity of genes encoding some reductive dehalogenases was also analyzed. Geochemical and 16S rRNA and RDH gene analyses, as a whole, provided insights into the microbial community complexity and the distribution of potential dechlorinators. Based on the data obtained, a possible network of metabolic interactions has been hypothesized to obtain an effective reductive dechlorination process.

Pleurotus ostreatusdual biofilms with bacteria are known to be involved in rock phosphate solubilization, endophytic colonization, and even in nitrogen fixation. Despite these relevant implications, no information is currently available on the architecture ofP. ostreatus-based dual biofilms. In addition to this, there is a limited amount of information regarding the estimation of the temporal changes in the relative abundances of the partners in such binary systems. To address these issues, a dual biofilm model system with this fungus was prepared by usingPseudomonas alcaliphila34 as the bacterial partner due to its very fast biofilm-forming ability. The application of the bacterial inoculum to already settled fungal biofilm on a polystyrene surface coated with hydroxyapatite was the most efficient approach to the production of the mixed system the ultrastructure of which was investigated by a multi-microscopy approach. Transmission electron microscopy analysis showed that the adhesion of bacterial cells onto the mycelial cell wall appeared to be mediated by the presence of an abundant layer of extracellular matrix (ECM). Scanning electron microscopy analysis showed that ECM filaments of bacterial origin formed initially a reticular structure that assumed a tabular semblance after 72 h, thus overshadowing the underlying mycelial network. Across the thickness of the mixed biofilms, the presence of an extensive network of channels with large aggregates of viable bacteria located on the edges of their lumina was found by confocal laser scanning microscopy; on the outermost biofilm layer, a significant fraction of dead bacterial cells was evident. Albeit with tangible differences, similar results regarding the estimation of the temporal shifts in the relative abundances of the two partners were obtained by two independent methods, the former relying on qPCR targeting of 16S and 18S rRNA genes and the latter on ester-linked fatty acid methyl esters analysis.

This paper presents a route for the treatment of MSWI fly (FA) and bottom ashes (BA) using microorganisms to critically assess whether bioleaching is within reach of effective industrial application. The leaching of metals from BA and FA was investigated in a controlled laboratory environment using a culture isolated from a natural system where the dominant strains are acidophilic bacteria, mainly Acidothiobacillus thiooxidans and Acidothiobacillus ferrooxidans. The community of microorganisms (mostly acidophilic, S- and Fe-oxidizing bacteria) was collected directly from overflows and ponds at the sediment–water interface of a natural system near a post-mining site. Pre-cultivation was done in 250 mL flasks followed by the adaptation to the different substrates (both FA and BA). The effect of different material pre-treatment and elemental sulphur concentrations were evaluated for both BA and FA, at a starting pH of 4. The bioleaching of BA and FA substrates experienced good yields of metal extraction with an optimum duration of two weeks. The results showed that more than 90% Zn, Cu, and 10% Pb are removed from FA; while 100% Cu, 80% Zn and 20% Pb are removed from BA samples. Batch experiments with regenerating ion-exchange resins did not perform well for metal recovery, but could serve as a valuable decontamination step. The techniques used here with FA and BA can be used for urban mining purposes (e.g. ashes and other meal-rich anthropogenic wastes), but also low-grade ores in the mining industry, contributing to resource recovery or decontamination agendas.

Naphthenic acids (NAs) are an important group of toxic organic compounds naturally occurring in hydrocarbon deposits. This work shows that Rhodococcus aetherivorans BCP1 cells not only utilize a mixture of eight different NAs (8XNAs) for growth but they are also capable of marked degradation of two model NAs, cyclohexanecarboxylic acid (CHCA) and cyclopentanecarboxylic acid (CPCA) when supplied at concentrations from 50 to 500 mgL−1 . The growth curves of BCP1 on 8XNAs, CHCA, and CPCA showed an initial lag phase not present in growth on glucose, which presumably was related to the toxic effects of NAs on the cell membrane permeability. BCP1 cell adaptation responses that allowed survival on NAs included changes in cell morphology, production of intracellular bodies and changes in fatty acid composition. Transmission electron microscopy (TEM) analysis of BCP1 cells grown on CHCA or CPCA showed a slight reduction in the cell size, the production of EPS-like material and intracellular electrontransparent and electron-dense inclusion bodies. The electron-transparent inclusions increased in the amount and size in NA-grown BCP1 cells under nitrogen limiting conditions and contained storage lipids as suggested by cell staining with the lipophilic Nile Blue A dye. Lipidomic analyses revealed significant changes with increases of methyl-branched (MBFA) and polyunsaturated fatty acids (PUFA) examining the fatty acid composition of NAs-growing BCP1 cells. PUFA biosynthesis is not usual in bacteria and, together with MBFA, can influence structural and functional processes with resulting effects on cell vitality. Finally, through the use of RT (Reverse Transcription)- qPCR, a gene cluster (chcpca) was found to be transcriptionally induced during the growth on CHCA and CPCA. Based on the expression and bioinformatics results, the predicted products of the chcpca gene cluster are proposed to be involved in aerobic NA degradation in R. aetherivorans BCP1. This study provides first insights into the genetic and metabolic mechanisms allowing a Rhodococcus strain to aerobically degrade NAs.&nbsp

The reactions between [Fe 6 C(CO) 16 ] 2− and CuCl, in refluxing THF, yield [Fe 5 C(CO) 14 (CuCl)] 2− ( 1 ), [Fe 4 C(CO) 12 (CuCl) 2 ] 2− ( 2 ), or [{Fe 4 Cu 2 C(CO) 12 (μ-Cl)} 2 ] 2− ( 3 ), depending on the Fe 6 /CuCl ratio. The chloro ligands of these clusters can be displaced either spontaneously, or by metal-assisted substitution, to give the bromo derivative [Fe 5 C(CO) 14 (CuBr)] 2− ( 4 ) or the solvento complexes [Fe 5 C(CO) 14 (CuTHF)] − ( 5 ) and [Fe 4 C(CO) 12 (CuNCMe) 2 ] ( 6 ). The latter can be also obtained directly, by metal substitution from [Fe 6 C(CO) 16 ] 2− and [Cu(NCMe) 4 ]BF 4 , or by polyhedral expansion from [Fe 4 C(CO) 12 ] 2− . All the clusters are octahedral, with the copper atoms in a pseudo-linear geometry, where one of the coordination positions is occupied by the interstitial carbide. The two copper atoms in the Fe 4 Cu 2 clusters are always in cis geometry and, in the dimer [{Fe 4 Cu 2 C(CO) 12 (μ-Cl)} 2 ] 2− , they are joined through chlorides. The role of the different metal centres in determining the redox activity of the heteronuclear Fe–Cu clusters 1 , 2 , 3 , has been studied by electrochemical methods. In the bridged dimer 3 , the two Fe 4 Cu 2 C cluster units resulted electronically not communicating.

Polychlorinated biphenyls (PCBs) are ubiquitous persistent organic pollutants that can be co-metabolically biotransformed by biphenyl-utilizing bacteria. In this study, terminal-restriction fragment length polymorphism (T-RFLP) was applied to the substrate specificity-determining region of the 2,3-biphenyl dioxygenase encoding genes of a microbial community found in a PCB-polluted soil. Notably, both the total biphenyl/PCB-utilizing community and its members actively expressing the 2,3-biphenyl dioxygenase gene were analyzed. T-RFLP fingerprinting along with gene library construction allowed us not only to detect biphenyl dioxygenases related to the well characterized catabolic patterns of Pseudomonas pseudoalcaligenes KF707 and Burkholderia xenovorans LB400, but also to reveal novel environmental enzyme classes displaying amino acid substitutions that may be related to broader specificity and improved catalytic properties. Furthermore, space and time of sampling along with bioavailability conditions of different PCBs were considered possible sources of profile variability.

Tellurite (TeO3(2-)) is the most toxic and soluble oxyanion among tellurium (Te) compounds. The effects of the metalloid anion on the oxidative stress response of the obligate aerobe Pseudomonas pseudoalcaligenes KF707 were investigated. Cells treated with sub-lethal concentrations of TeO3(2-) showed neither adaptation to it nor cross-protection against oxidants such as 1,1'-4,4'-bipyridinium dichloride (paraquat, PQ2+), diazenedicarboxylic acid bis-N,N-dimethylamide (diamide), tert-butyl hydroperoxide (tBH) and hydrogen peroxide (H2O2). Notably, TeO3(2-) exerted a synergic effect on the toxicity of these latter oxidants. Tellurite was shown to decrease the cellular content of reduced thiols (RSH) with a consequent increase in the production of reactive oxygen species (ROS) and stimulation of the superoxide dismutase (SOD) activity. However, since the time course of ROS production by TeO3(2) (t1/2 > 30 min) was much slower than that with PQ2+ and/or diamide (t1/2

Pseudomonas pseudoalcaligenes KF707 is a soil polychlorinated biphenyl (PCB) degrader, able to grow both planktonically and as a biofilm in the presence of various toxic metals and metalloids. Here we report the genome sequence (5,957,359 bp) of P. pseudoalcaligenes KF707, which provides insights into metabolic degradation pathways, flagellar motility, and chemotaxis.

The reaction between [Fe2Ir2(CO)12]2− and diphenylacetylene in refluxing CH3CN yields the substituted cluster [Fe2Ir2(CO)10(PhC2Ph)]2− (1). In the crystals, the four metal atoms define a butterfly arrangement whose Ir–Ir hinge is parallel to the acetylenic C2 unit. The neutral triangular cluster [FeIr2(CO)9(PhC2Ph)] (2) is obtained by the treatment of 1 with acids at room temperature; in this 48 valence electrons species, the C–C and the Ir–Ir bonds are also parallel, in the μ 3 – η ∥ 2 coordination mode. The cluster [Fe2Rh(CO)10]− reacts with diphenylacetylene in refluxing THF yielding [Fe2Rh(CO)8(PhC2Ph)]− (3). In this 46 C.V.E.’s cluster, the C2 unit is perpendicular to the Fe–Fe edge, exemplifying the μ 3 – η ⊥ 2 bonding mode. According to 13C NMR spectra, the structure of the three clusters is maintained in solution. Electrochemical investigations show that the one-electron oxidation of [Fe2Ir2(CO)10(L)]2− (L = 2CO, PhC2Ph) as well as the one-electron reduction of [Fe2Rh(CO)8(PhC2Ph)]− only generates the respective short lived products.

The susceptibility to various biocides was examined in planktonic cells and biofilms of the obligate aerobe, PCBs degrader, Pseudomonas pseudoalcaligenes KF707. The toxicity of two antibiotics, amikacin and rifampicin, three metalloid oxyanions (AsO2 −, SeO3 2−, TeO3 2−) and three metal cations (Cd2+, Ni2+, Al3+) was tested at two stages of the biofilm-development (4 and 24 h) and compared to planktonic cells susceptibility. Mature biofilms formed in rich (LB, Luria–Bertani) medium were thicker (23 μm) than biofilms grown in minimal (SA saccarose-arginine) medium (13 μm). Early grown (4 h) SA-biofilms, which consisted of a few sparse/attached cells, were 50–100 times more resistant to antibiotics than planktonic cells. Conversely, minor changes in tolerance to metal(loid)s were seen in both SA- and LB-grown biofilms. In contrast to planktonic cells, no reduction of TeO3 2− to elemental Te(0) or SeO3 2− to elemental Se(0) was seen in KF707 biofilms. The data indicate that: (a) metal tolerance in KF707 biofilms, under the growth and exposure conditions described here, is different than antibiotic tolerance; (b) KF707 planktonic cells and biofilms, are almost equally susceptible to killing by metal cations and oxyanions, and (c) biofilm-tolerance to TeO3 2− and SeO3 2− is not linked to metalloid reduction; this means that KF707 planktonic cells and biofilms differ in their physiology and strategy to counteract metalloid toxicity.

The focus of this microcosm study was to monitor the performances of 17 butane-utilizing microcosms during a long-term (100-250 days) aerobic cometabolic depletion of chloroform (CF). The depletion of the contaminant began after a lag-time variable between 0 and 23 days. All microcosms quickly reached a pseudo steady-state condition, in terms of biomass concentration (with an average of 9.3 x 106 CFU ml(-1)), chloroform depletion rate (5 micromol l(-1) d(-1)) and butane utilization rate (730 micromol l(-1) d(-1)). After about 100 days of CF depletion, a sudden 5- to 7-fold increase of the chloroform rate was observed in two microcosms, where the highest amount of contaminant had been depleted. In one of these high-performing microcosms, an experiment of chloroform depletion in the absence of butane resulted in the depletion of a surprisingly high amount of contaminant (765 micromolCF kg(-1) dry soil in 2 months) and in a marked selection of a single bacterial strain. Bioaugmentation assays conducted with the biomass selected in this microcosm and with a pure culture of the selected strain immediately resulted in very high chloroform depletion rates. Preliminary results of a study conducted with resting cells of the selected strain indicated that it can degrade chloroform concentrations up to 119 microM (14.2 mg l(-1)) without any sign of substrate toxicity, and that it is able to transform vinyl chloride and 1,1,2-trichloroethane.

This study shows that the oxyanion tellurite TeO32- can be used as a tool to detect and quantify the release in soil microcosms of Pseudomonas pseudoalcaligenes KF707, a strain spontaneously resistant to tellurite with a minimal inhibitory concentration (MIC) of 150 μg ml-1. KF707 cells which carry the genes for degradation of a wide range of polychlorinated biphenyl congeners (PCBs) were used for inoculation of laboratory microcosms prepared with two different PCB-contaminated soils (Ci/s and Di/s) in the presence or absence of biphenyl as carbon source. In all microcosms supplemented with biphenyl, significant survival of strain KF707 was noted over a time period of 35 days; conversely, in microcosms containing Ci/s soil without biphenyl addition a rapid decrease in KF707 inoculated cells was observed. By comparing the number of inoculated KF707 cells with the number of indigenous bacteria growing on biphenyl (IBGB) of both Ci/s and Di/s microcosms, it could be concluded that the KF707/IBGB ratio is a relevant parameter in determining the fate of the added strain. The efficacy of potassium tellurite as a selective marker to monitor strain KF707 in laboratory microcosms was confirmed by ARDRA analyses of the 16S rDNA, while the isolated indigenous bacteria growing on biphenyl were identified as members of three different species of the genus Pseudomonas. We also report that in microcosms inoculated with KF707 cells in the absence of biphenyl, only low chlorinated biphenyls were degraded. © 2002 Éditions scientifiques et médicales Elsevier SAS. All rights reserved.