RESUMEN
The Antarctic bacterium Pseudoalteromonas haloplanktis TAC125 is a model organism of cold-adapted bacteria. The interest in the study of this psychrophilic bacterium stems from its capability either as a non-conventional system for production of recombinant protein and as a rich source of bioactive compounds. To further explore the biotechnological ability of P. haloplanktis TAC125, we have developed a synthetic medium, containing D-gluconate and L-glutamate (GG), which allows the bacterium to grow even at subzero temperatures. P. haloplanktis TAC125 growing in GG medium at low temperature displays growth kinetic parameters which confirm its spectacular adaptation to cold environment and subzero lifestyle, paving the way to the definition of the underlying molecular strategies. Moreover, in this paper, we report the setup of a finely regulated gene expression system inducible by D-galactose to produce recombinant protein in GG synthetic medium at temperatures as low as -2.5 °C. Thanks to the combination of the novel medium and the new expression system, we obtained for the first time the production of a recombinant protein at subzero temperature, thus providing an innovative strategy for the recombinant production of "difficult" proteins.
Asunto(s)
Medios de Cultivo/química , Pseudoalteromonas/crecimiento & desarrollo , Pseudoalteromonas/metabolismo , Proteínas Recombinantes/metabolismo , Frío , Expresión Génica , Ingeniería Genética/métodos , Vectores Genéticos , Pseudoalteromonas/genéticaRESUMEN
We construct asymptotically safe extensions of the standard model by adding gauged vectorlike fermions. Using large number-of-flavor techniques we argue that all gauge couplings, including the hypercharge and, under certain conditions, the Higgs coupling, can achieve an interacting ultraviolet fixed point.
RESUMEN
Staphylococcus epidermidis is recognized as cause of biofilm-associated infections and interest in the development of new approaches for S. epidermidis biofilm treatment has increased. In a previous paper we reported that the supernatant of Antarctic bacterium Pseudoalteromonas haloplanktis TAC125 presents an anti-biofilm activity against S. epidermidis and preliminary physico-chemical characterization of the supernatant suggested that this activity is due to a polysaccharide. In this work we further investigated the chemical nature of the anti-biofilm P. haloplanktis TAC125 molecule. The production of the molecule was evaluated in different conditions, and reported data demonstrated that it is produced in all P. haloplanktis TAC125 biofilm growth stages, also in minimal medium and at different temperatures. By using a surface coating assay, the surfactant nature of the anti-biofilm compound was excluded. Moreover, a purification procedure was set up and the analysis of an enriched fraction demonstrated that the anti-biofilm activity is not due to a polysaccharide molecule but that it is due to small hydrophobic molecules that likely work as signal. The enriched fraction was also used to evaluate the effect on S. epidermidis biofilm formation in dynamic condition by BioFlux system.
Asunto(s)
Biopelículas/crecimiento & desarrollo , Pseudoalteromonas/fisiología , Staphylococcus epidermidis/fisiología , Regiones Antárticas , Polisacáridos/metabolismo , Pseudoalteromonas/metabolismo , Staphylococcus epidermidis/metabolismo , Tensoactivos/metabolismoRESUMEN
Dihydrogenarsenate [H(2)AsO(4)(-), As(V)] or dichromate [Cr(2)O(7)(2-), Cr(VI)] at pH=4.0 showed to be sorbed on a Fe(OH)(x)-polymerin complex and ferrihydrite to a greater extent than on polymerin, the organic polymeric fraction of olive oil mill wastewater (OMW). In particular, the maximum amount (x(m)) of arsenate sorbed on Fe(OH)(x)-polymerin complex was similar to that on ferrihydrite (880.26 and 743.02 mmol kg(-1), respectively), and was much greater than that sorbed on polymerin (384.25 mmol kg(-1)). The sorption of dichromate was to a comparable extent on Fe(OH)(x)-polymerin complex and ferrihydrite (205.90 and 254.88 mmol kg(-1), respectively). Cr(III), a less toxic chromium form, mainly, and Cr(V) were indeed the effective forms sorbed on polymerin (200 mmol kg(-1)), as a consequence of the redox reaction of the strongly toxic Cr(VI) with the CH(2)OH groups of the polysaccharide moiety of this bio-sorbent, according to the data deriving from XPS and DRIFT analyses. The potential exploitation of the selected sorbents for the removal of As(V) or Cr(VI) from aqueous effluents is briefly discussed.
Asunto(s)
Arseniatos/aislamiento & purificación , Cromatos/aislamiento & purificación , Compuestos Férricos/química , Residuos Industriales/prevención & control , Polímeros/química , Contaminantes Químicos del Agua/aislamiento & purificación , Adsorción , Aniones , Oxidación-ReducciónRESUMEN
This study investigated the sorption of paraquat and 2,4-D on polymerin, the humic acid-like fraction of olive mill wastewater. Effects of pH, contact time, initial concentration and sorbent dosage on the sorption of both herbicides were studied. The sorption mechanism of paraquat on polymerin was consistent with the ion exchange of this herbicide with Ca, Mg and K natively occurring in the sorbent; in contrast, 2,4-D was bound to polymerin by hydrogen bonding. Simulated wastewaters contaminated with paraquat were purified after three sorption cycles on polymerin renewed at each cycle, at a solid/liquid ratio of 0.5, whereas those containing 2,4-D showed a maximal residue removal of 44% after two sorption cycles at the same ratio. The possible application of this model to other water-soluble herbicides, as well as the possible exploitation of polymerin as a bio-filter for the decontamination of pollution point sources is briefly discussed.
Asunto(s)
Ácido 2,4-Diclorofenoxiacético/química , Herbicidas/química , Residuos Industriales , Olea , Paraquat/química , Polímeros/química , Contaminantes Químicos del Agua/química , Adsorción , Industria de Procesamiento de Alimentos , Eliminación de Residuos Líquidos/métodos , Purificación del Agua/métodosRESUMEN
Dry olive mill residue (DOR) from the olive oil production by two phase centrifugation system was fractionated by a consecutive continuous solid-liquid extraction obtaining the EAF, PF, MF and WF fractions with ethyl acetate, n-propanol, methanol and water, respectively. The chemical, chromatographic and mass spectrometric analyses showed EAF, PF and MF to be mainly composed of simple phenols, phenolic acids, flavonoids and glycosilated phenols (glycosides of phenols, secoiridoids and flavonoids), whereas WF was mainly consisting of polymerin, the metal organic polymeric mixture previously identified in olive oil mill waste waters and composed of carbohydrates, melanin, proteins and metals (K, Na, Ca, Mg and Fe). The identification in DOR of oleoside, 6'-beta-glucopyranosyl-oleoside and 6'-beta-rhamnopyranosyl-oleoside, and of its organic polymeric component, known as polymerin, are reported for the first time in this paper. The inoculation of the previously mentioned fractions with saprobe fungi Coriolopsis rigida, Pycnoporus cynnabarinus or Trametes versicolor indicated these fungi to be able to metabolize both the phenols and glycosilated phenols, but not polymerin. In correspondence, EAF, PF, MF and WF, which proved to be toxic on Lepidium sativum, decreased their toxicity after incubation with the selected fungi, WF showing to be also able to stimulate the growth of the selected seeds. The phytotoxicity appeared mainly correlated to the monomeric phenols and, to a lesser extent, to the glycosilated phenols, whereas polymerin proved to be non toxic. However, the laccase activity was not associated with the decrease of phytotoxicity. The valorization of DOR as a producer of high added value substances of industrial and agricultural interest in native form and after their bioremediation for a final objective of the total DOR recycling is also discussed.
Asunto(s)
Restauración y Remediación Ambiental/métodos , Lepidium sativum/química , Aceites de Plantas/química , Cromatografía Líquida de Alta Presión , Aceite de Oliva , Espectrometría de Masa por Ionización de Electrospray , Espectrofotometría UltravioletaRESUMEN
Some saprobe fungi (Phlebia radiata, Trametes versicolor, Coriolopsis rigida, Pycnoporus cinnabarinus, Fomes sclerodermus or Pleurotus pulmonarius) were able to bioconvert the ethyl acetate fraction (DEAF) and the corresponding aqueous exhausted fraction (EAF) of dry olive mill residue (DOR), reducing their phytotoxicity on Lepidium sativum seeds. Large amount of hydroxytyrosol together with other eight monomeric phenols were found in the native DEAF fraction, which represents a good source of antioxidants. P. radiata, T. versicolor and F. sclerodermus caused an effective phytotoxicity reduction of EAF in the concentration range of 25-3 gl(-1). In particular, in the range between 12.5 and 3 gl(-1), the EAF samples inoculated with P. radiata and F. sclerodermus surprisingly stimulated the germinability of L. sativum, suggesting their use as a potential biofertilizer. This is the first report which showed the bioconversion of the above fractions in shorter time with respect to the previous findings concerning DOR. The possible implications of laccase in the decrease of DEAF and EAF phytotoxicity was also discussed.
Asunto(s)
Acetatos/química , Basidiomycota/metabolismo , Residuos Industriales/prevención & control , Aceites de Plantas/química , Acetatos/metabolismo , Basidiomycota/crecimiento & desarrollo , Biodegradación Ambiental , Cromatografía Líquida de Alta Presión , Germinación/efectos de los fármacos , Residuos Industriales/análisis , Lacasa/metabolismo , Lepidium sativum/efectos de los fármacos , Estructura Molecular , Aceite de Oliva , Fenoles/metabolismo , Aceites de Plantas/metabolismo , Semillas/efectos de los fármacos , Espectrometría de Masa por Ionización de Electrospray , Contaminantes Químicos del Agua/metabolismo , Contaminantes Químicos del Agua/toxicidadRESUMEN
The transformation by an oxidoreductase (a laccase from Rhus vernificera) of a mixture of four phenols (catechol, methylcatechol, m-tyrosol and hydroxytyrosol) that simulates a typical wastewater derived from an olive oil factory was investigated. Results achieved in this study confirm that laccase-mediated transformation of phenols depends on the nature and the initial concentration of the involved phenol, the time course of the reaction, and mainly, on the complexity of the phenolic incubation mixture. Actually, the four phenols each have a completely different response to enzyme action both in terms of quantitative and kinetic transformation. For example, after 24-h incubation, methylcatechol was completely removed, whereas 30% of untransformed hydroxytyrosol and catechol and more than 65% of m-tyrosol were still present in the reaction mixture. A reduction of enzyme activity occurred for all phenols after enzymatic oxidation. No correspondence between phenol transformation and disappearance of enzymatic activity was observed, thus suggesting that different mechanisms are probably involved in the laccase-mediated transformation of the four phenols. The behavior of phenols became more complex when an increasing number of phenols was present in the reaction mixture, and even more so when different concentrations of phenols were used. Competitive effects may arise when more than one phenol is present in the reaction solution and interacts with the enzyme.
Asunto(s)
Oxidorreductasas/farmacología , Fenoles/química , Fenoles/metabolismo , Contaminantes del Agua/metabolismo , Lacasa , Oxidación-Reducción , Rhus/enzimología , Eliminación de Residuos LíquidosRESUMEN
The influence of four pesticides, e.g. glyphosate, paraquat, atrazine, and carbaryl, on the activities of invertase, urease and phosphatase of twenty-two soils, numbered as 1-22, was investigated. Soils displayed a general variability of enzyme activities with invertase being more abundant than urease and phosphatase in the order listed. The addition of glyphosate and paraquat activated invertase and urease activities in several soils. Increments of invertase activity ranged from a very low increase (+4%) up to +204% in soils 11 and 14, respectively. Smaller increases were measured for urease. A general inhibitory effect (from 5% to 98%) was observed for phosphatase in the presence of glyphosate. The effects of atrazine and carbaryl on the three soil enzymes were evaluated against that exhibited by methanol, the solvent used for their solubilization. In almost all soils, atrazine further inhibited invertase activity with respect to the inhibitory effect shown by methanol. By contrast, consistent activation effects (from 61% to 10217%) were measured for urease with methanol alone and/or methanol-pesticide mixtures. Contradictory results were observed with phosphatase. Similarities found between the results obtained with enzymes in soils and those measured with synthetic enzyme complexes (e.g. free enzymes and/or clay-, organo-, and organo-clay-enzyme complexes) exposed to the same pesticides allowed some relationships between responses of soil enzymes to pesticides and soil properties to be hypothesized.
Asunto(s)
Glicósido Hidrolasas/metabolismo , Plaguicidas/efectos adversos , Monoéster Fosfórico Hidrolasas/metabolismo , Microbiología del Suelo , Ureasa/metabolismo , Monitoreo del Ambiente , Minerales , Suelo , Solubilidad , beta-FructofuranosidasaRESUMEN
An Al(OH)x-montmorillonite (chlorite) complex (AM18) was prepared and 2,4-dichlorophenoxyacetic acid (2,4-D) sorbed to saturation. After several washing cycles the 'strongly sorbed' 2,4-D was 507 micrograms g-1 AM18. The bioavailability of sorbed 2,4-D was assessed in a minimal salts medium with the AM18-2,4-D as the sole C and energy source. Over a 28-day period a Pseudomonas sp. degraded 23% more of the sorbed 2,4-D than could be accounted for by desorption from AM18 in the non-inoculated controls. Possible explanations for the increase in bioavailability are presented.
Asunto(s)
Ácido 2,4-Diclorofenoxiacético/metabolismo , Cloruros/química , Herbicidas/metabolismo , Ácido 2,4-Diclorofenoxiacético/química , Adsorción , Herbicidas/química , Pseudomonas/metabolismoRESUMEN
Ultrasound assessment of septum thickness is useful in twin pregnancies for predicting the type of placentation. In fact, its greater or lesser acoustic resonance distinguishes monochorionic or dichorionic pregnancies. This makes adoption of therapeutic measures more secure in the event of pathology involving only one of the two fetuses.
Asunto(s)
Placentación , Embarazo Múltiple , Ultrasonografía , Adulto , Femenino , Humanos , Embarazo , GemelosRESUMEN
Se efectuó valvuloplastia pulmonar percutánea en 16 pacientes con estenosis pulmonar valvular congénita entre los meses de junio y noviembre de 1987, con edad promedio de 6.5 años. Por vía percutánea se realizó el cateterismo y angiocardiografía confirmatorios. Preferentemente se practicó la valvuloplastia con balón de mayor diámetro (20%) que el anillo valvular pulmonar. En 12 de 16 pacientes sometidos a esta técnica, se obtuvo un dramático descenso de la gradiente transvalvular pulmonar, hasta cifras consideradas no quirúrgicas (gradiente menor a 50 mmHg). En 2 niños, la gradiente no se modificó y en otros 2 esta descendió a cifras aún quirúrgicas, pensamos que podría haber un descenso futuro espontáneo al ceder la estenosis pulmonar infundibular reactiva de éstos pacientes. Hubo un fracaso en que no se logró franquear la válvula pulmonar por la presencia de banda muscular en el infundíbulo, y debió ser intervenido quirúrgicamente. No hubo complicaciones importantes, solo bradicardia e hipotensión arterial pasajera durante la dilatación del balón. El promedio de hospitalización fue de 48 horas. Se concluye que éste procedimiento es una alternativa efectivo, seguro y económico en el tratamiento de la estenosis pulmonar valvular congénita
Asunto(s)
Lactante , Preescolar , Niño , Humanos , Estenosis de la Válvula Pulmonar/congénito , Estenosis de la Válvula Pulmonar/terapia , HemodinámicaRESUMEN
PIP: 330 women with a median age of 30.15 (+- 9.5) years sought gynecological consultation for advice on contraception and for cervical carcinoma screening. Anamnesis explored the presence of dysuria, dyspareunia, secretions, and pelvic pain, the number of partners, and type of contraceptive used. Endocervical samples were collected by means of tampon and the specimens were analyzed for 48 to 120 hours to find antigens of Chlamydia trachomatis (C.T.) by a solid phase immunoenzymatic test. Peripheral blood samples were also taken from all women to look for antibodies of C.T. and also the indirect immunoperoxidase test was used to search for specific antibodies of C.T. (IgM, IgA, IgE, IgG). The chi-square test was applied for statistical analysis. None of the women who used oral hormonal contraceptives or condoms were infected (presence of antigens and positivity for IgM and/or IgE and/or IgA), however, 36 of 90 IUD users (40%) were infected, 18 of 132 women who used no contraceptives whatsoever (13.7%) were also infected. 91% of the subjects had a single partner. In view of these findings the use of the condom and oral contraceptives is recommended with proper instruction about their potential side effects.^ieng