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1.
Eur J Pediatr Surg ; 2024 Jun 07.
Artigo em Inglês | MEDLINE | ID: mdl-38848756

RESUMO

INTRODUCTION: Abdominal adhesions following surgery can lead to complications like intestinal obstruction and pelvic pain. While no molecular therapies currently target the underlying adhesion formation process, various barrier agents exist. 4DryField® has shown promise in reducing bleeding and adhesions in adults. This study aimed to assess its effectiveness in children. METHODS: The study examined all pediatric patients who underwent laparotomy between January 2018 and February 2022. It compared outcomes between those treated with 4DryField® and a control group. Key endpoints included surgical revision, adhesion recurrence, infections, insufficiencies, fever, CRP levels, and time to gastrointestinal passage. RESULTS: In total, 233 children had surgery for bowel adhesions. After propensity score matching, 82 patients were included in the analysis: 39 in the control and 43 in the 4DryField® group. 4DryField® did not affect re-adhesion rate. Children in the treatment group had significantly more complications (47% vs. 15%, p=0.002), more often fever and higher CRP levels. CONCLUSIONS: 4DryField® did not show potential in reducing adhesion formation, but it was associated with significantly more complications in pediatric patients. Thus, future prospective studies to evaluate the safety and effectiveness of 4DryField® in children.

2.
Nature ; 630(8017): 636-642, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38811732

RESUMO

Chemical vapour deposition (CVD) synthesis of graphene on copper has been broadly adopted since the first demonstration of this process1. However, widespread use of CVD-grown graphene for basic science and applications has been hindered by challenges with reproducibility2 and quality3. Here we identify trace oxygen as a key factor determining the growth trajectory and quality for graphene grown by low-pressure CVD. Oxygen-free chemical vapour deposition (OF-CVD) synthesis is fast and highly reproducible, with kinetics that can be described by a compact model, whereas adding trace oxygen leads to suppressed nucleation and slower/incomplete growth. Oxygen affects graphene quality as assessed by surface contamination, emergence of the Raman D peak and decrease in electrical conductivity. Epitaxial graphene grown in oxygen-free conditions is contamination-free and shows no detectable D peak. After dry transfer and boron nitride encapsulation, it shows room-temperature electrical-transport behaviour close to that of exfoliated graphene. A graphite-gated device shows well-developed integer and fractional quantum Hall effects. By highlighting the importance of eliminating trace oxygen, this work provides guidance for future CVD system design and operation. The increased reproducibility and quality afforded by OF-CVD synthesis will broadly influence basic research and applications of graphene.


Assuntos
Condutividade Elétrica , Grafite , Oxigênio , Grafite/química , Oxigênio/química , Reprodutibilidade dos Testes , Compostos de Boro/química , Compostos de Boro/síntese química , Análise Espectral Raman , Gases/química , Cobre/química , Cinética , Temperatura
3.
Biol Methods Protoc ; 9(1): bpae022, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38628556

RESUMO

Cell replacement in aganglionic intestines is a promising, yet merely experimental tool for the therapy of congenital dysganglionosis of the enteric nervous system like Hirschsprung disease. While the injection of single cells or neurospheres to a defined and very restricted location is trivial, the translation to the clinical application, where large aganglionic or hypoganglionic areas need to be colonized (hundreds of square centimetres), afford a homogeneous distribution of multiple neurospheres all over the affected tissue areas. Reaching the entire aganglionic area in vivo is critical for the restoration of peristaltic function. The latter mainly depends on an intact nervous system that extends throughout the organ. Intra-arterial injection is a common method in cell therapy and may be the key to delivering cells or neurospheres into the capillary bed of the colon with area-wide distribution. We describe an experimental method for monitoring the distribution of a defined number of neurospheres into porcine recta ex vivo, immediately after intra-arterial injection. We designed this method to localize grafting sites of single neurospheres in precise biopsies which can further be examined in explant cultures. The isolated perfused porcine rectum allowed us to continuously monitor the perfusion pressure. A blockage of too many capillaries would lead to an ischaemic situation and an increase of perfusion pressure. Since we could demonstrate that the area-wide delivery of neurospheres did not alter the overall vascular resistance, we showed that the delivery does not significantly impair the local circulation.

4.
Pain ; 165(3): e1-e14, 2024 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-38284423

RESUMO

ABSTRACT: Pain sensitivity of healthy subjects in the cold-pressor (CP) test was proposed to be dichotomously distributed and to represent a pain sensitivity trait. Still, it has not been systematically explored which factors influence this pain sensitivity readout. The aim of this study was to distinguish potential contributions of local tissue-related factors such as perfusion and thermoregulation or gain settings in nociceptive systems. Cold-pressor-sensitive and CP-insensitive students screened from a medical student laboratory course were recruited for a CP retest with additional cardiovascular and bilateral local vascular monitoring. In addition, comprehensive quantitative sensory testing according to Deutscher Forschungsverbund Neuropathischer Schmerz standards and a sustained pinch test were performed. Cold pressor was reproducible across sessions (Cohen kappa 0.61 ± 0.14, P < 0.005). At 30 seconds in ice water, CP-sensitive subjects exhibited not only more pain (78.6 ± 26.3 vs 29.5 ± 17.5, P < 0.0001) but also significantly stronger increases in mean arterial blood pressure (12.6 ± 9.3 vs 5.6 ± 8.1 mm Hg, P < 0.05) and heart rate (15.0 ± 8.2 vs 7.1 ± 6.2 bpm, P < 0.005), and lower baroreflex sensitivity, but not local or vasoconstrictor reflex-mediated microcirculatory responses. Cold-pressor-sensitive subjects exhibited significantly lower pain thresholds also for cold, heat, and blunt pressure, and enhanced pain summation, but no significant differences in Aδ-nociceptor-mediated punctate mechanical pain. In conclusion, differences in nociceptive signal processing drove systemic cardiovascular responses. Baroreceptor activation suppressed pain and cardiovascular responses more efficiently in CP-insensitive subjects. Cold-pressor sensitivity generalized to a pain trait of C-fiber-mediated nociceptive channels, which was independent of local thermal and vascular changes in the ice-water-exposed hand. Thus, the C-fiber pain trait reflects gain setting of the nociceptive system.


Assuntos
Nociceptores , Limiar da Dor , Humanos , Limiar da Dor/fisiologia , Microcirculação , Dor , Frequência Cardíaca , Água , Temperatura Baixa , Pressão Sanguínea
5.
Children (Basel) ; 10(11)2023 Oct 30.
Artigo em Inglês | MEDLINE | ID: mdl-38002849

RESUMO

BACKGROUND: The purpose of this report is to describe the seminal case of a near-term human fetus with a life-threatening left diaphragmatic hernia that underwent fetoscopic tracheal occlusion (FETO) combined with fetoscopic partial removal of herniated bowel from the fetal chest by fetoscopic laparoschisis (FETO-LAP). CASE SUMMARY: A life-threatening left diaphragmatic hernia (liver-up; o/e LHR of ≤25%; MRI lung volume ≤ 20%) was observed in a human fetus at 34 weeks of gestation. After counselling the mother about the high risks of postnatal demise if left untreated, the expected limitations of fetoscopic tracheal occlusion (FETO), and the previously untested option of combining FETO with fetoscopic laparoschisis, i.e., partial removal of the herniated bowel from the fetal chest (FETO-LAP), she consented to the latter novel treatment approach. FETO-LAP was performed at 36 + 5 weeks of gestation under general maternofetal anesthesia. Mother and fetus tolerated the procedure well. The neonate was delivered and the balloon removed on placental support at 37 + 2 weeks of gestation. On ECMO, a rapid increase in tidal volume was seen over the next eight days. Unfortunately, after this period, blood clots obstructed the ECMO circuit and the neonate passed away. DISCUSSION: This seminal case shows that in a fetus with severe left diaphragmatic hernia, partial removal of the herniated organs from the fetal chest is not only possible by minimally invasive fetoscopic techniques but also well tolerated. As the effect of FETO alone is limited in saving severely affected fetuses, combining FETO with fetoscopic laparoschisis (FETO-LAP) offers a new therapeutic route with multiple, potentially life-saving implications.

6.
Chemosphere ; 342: 140169, 2023 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-37709057

RESUMO

Diesel was accidently released into the shallow subsurface at an industrial site in the province of Québec, Canada, in the late 1980s. Subsequent remediation efforts removed much of the contamination; however, traces of petroleum hydrocarbons continue to impact the local aquifer. In addition to the historical diesel spill, more recent yet unconfirmed accidental releases from ongoing on-site and neighbouring industrial activities may have potentially contributed to elevated levels of polycyclic aromatic compounds (PACs) in groundwater. To identify the main source(s) of contamination, compound-specific stable carbon isotope ratios (δ13C) of PACs in groundwater monitoring wells were compared to those in asphalt produced from a nearby plant and in fuel oil #6 oil being used by local industry. The δ13C values of five individual compounds (biphenyl, C2-naphthalene, C1-fluorene, dibenzothiophene and phenanthrene) and two groups of combined C1-phenanthrenes/anthracenes in all groundwater samples were within analytical uncertainty (±0.5‰). Moreover, the δ13CPAC values in groundwater samples were distinct from those in asphalt and fuel oil #6, indicating negligible contributions from these sources. The similarity in δ13CPAC values across monitoring wells, including one situated in the former source zone containing a floating hydrocarbon phase, pointed to a common source of subsurface contamination that was attributed to the historical diesel spill. These results thus demonstrate that δ13CPAC values can be used for source apportionment in shallow aquifers decades after the original spill event.


Assuntos
Óleos Combustíveis , Água Subterrânea , Hidrocarbonetos Policíclicos Aromáticos , Compostos Policíclicos , Monitoramento Ambiental/métodos , Isótopos de Carbono/análise , Hidrocarbonetos Policíclicos Aromáticos/análise
7.
Environ Sci Pollut Res Int ; 30(28): 72793-72806, 2023 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-37178293

RESUMO

As an efficient method to remove contaminants from highly polluted sites, enzyme biodegradation addresses unresolved issues such as bioremediation inefficiency. In this study, the key enzymes involved in PAH degradation were brought together from different arctic strains for the biodegradation of highly contaminated soil. These enzymes were produced via a multi-culture of psychrophilic Pseudomonas and Rhodococcus strains. As a result of biosurfactant production, the removal of pyrene was sufficiently prompted by Alcanivorax borkumensis. The key enzymes (e.g., naphthalene dioxygenase, pyrene dioxygenase, catechol-2,3 dioxygenase, 1-hydroxy-2-naphthoate hydroxylase, protocatechuic acid 3,4-dioxygenase) obtained via multi-culture were characterized by tandem LC-MS/MS and kinetic studies. To simulate in situ application of produced enzyme solutions, pyrene- and dilbit-contaminated soil was bioremediated in soil columns and flask tests by injecting enzyme cocktails from the most promising consortia. The enzyme cocktail contained about 35.2 U/mg protein pyrene dioxygenase, 61.4 U/mg protein naphthalene dioxygenase, 56.5 U/mg protein catechol-2,3-dioxygenase, 6.1 U/mg protein 1-hydroxy-2-naphthoate hydroxylase, and 33.5 U/mg protein protocatechuic acid (P3,4D) 3,4-dioxygenase enzymes. It was found that after 6 weeks, the average pyrene removal values showed that the enzyme solution could be effective in the soil column system (80-85% degradation of pyrene).


Assuntos
Dioxigenases , Hidrocarbonetos Policíclicos Aromáticos , Poluentes do Solo , Hidrocarbonetos Policíclicos Aromáticos/metabolismo , Biodegradação Ambiental , Solo , Cinética , Cromatografia Líquida , Poluentes do Solo/metabolismo , Espectrometria de Massas em Tandem , Pirenos/metabolismo , Bactérias/metabolismo , Dioxigenases/metabolismo , Oxigenases de Função Mista/metabolismo , Microbiologia do Solo
8.
J Hazard Mater ; 450: 131078, 2023 05 15.
Artigo em Inglês | MEDLINE | ID: mdl-36848843

RESUMO

Despite recent attention being paid to the biodegradation of petroleum hydrocarbons in cold environments, scale-up studies of biodegradation are lacking. Herein, the effect of scale-up on the enzymatic biodegradation of highly contaminated soil at low temperatures was studied. A novel cold-adapted bacteria (Arthrobacter sp. S2TR-06) was isolated that could produce cold-active degradative enzymes (xylene monooxygenase (XMO) and catechol 2,3-dioxygenase (C2,3D)). Enzyme production was investigated on 4 different scales (lab to pilot scale). The results showed a shorter fermentation time, and the highest production of enzymes and biomass (107 g/L for biomass, 109 U/mL, and 203 U/mL for XMO and C2,3D after 24 h) was achieved in the 150-L bioreactor due to enhanced oxygenation. Multi-pulse injection of p-xylene into the production medium was needed every 6 h. The stability of membrane-bound enzymes can be increased up to 3-fold by adding FeSO4 at 0.1% (w/v) before extraction. Soil tests also showed that biodegradation is scale-dependent. The maximum biodegradation rate decreased from 100% at lab-scale to 36% in the 300-L sand tank tests due to limited access of enzymes to trapped p-xylene in soil pores, low dissolved oxygen in the water-saturated zone, soil heterogeneity, and the presence of the free phase of p-xylene. The result demonstrated that formulation of enzyme mixture with FeSO4 and direct injection of enzyme mixture (third scenario) can increase the efficiency of bioremediation in heterogeneous soil. In this study, it was demonstrated that cold-active degradative enzyme production can be scaled up to an industrial scale and enzymatic treatment can be used to effectively bioremediate p-xylene contaminated sites. This study could provide key scale-up guidance for the enzymatic bioremediation of mono-aromatic pollutants in water-saturated soil under cold conditions.


Assuntos
Petróleo , Poluentes do Solo , Solo , Biodegradação Ambiental , Poluentes do Solo/metabolismo , Hidrocarbonetos/metabolismo , Petróleo/metabolismo , Reatores Biológicos , Microbiologia do Solo
9.
Environ Pollut ; 322: 121170, 2023 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-36736816

RESUMO

The oil sands region in Western Canada is one of the world's largest proven oil reserves. To facilitate pipeline transport, highly viscous oil sands bitumen is blended with lighter hydrocarbon fractions to produce diluted bitumen (dilbit). Anticipated increases in dilbit production and transport raise the risk of inland spills. To understand the behaviour of dilbit in the unsaturated or vadose zone following a surface spill, we ran parallel dilbit and conventional heavy crude exposures, along with an untreated control, using large soil-filled columns over 104 days. Phospholipid fatty acids (PLFAs), biomarkers for the active microbial population, were extracted from column soil cores. Stable carbon isotope contents (δ13C) of individual PLFAs and radiocarbon contents (Δ14C) of bulk PLFAs were characterized over the course of the experiment. The Δ14CPLFA values in soils impacted by dilbit (-221.1 to -54.7‰) and conventional heavy crude (-259.4 to -97.9‰) indicated similar levels of microbial uptake of fossil carbon. In contrast, Δ14CPLFA values in the control column (-46.1 to +53.7‰) reflected assimilation of more recently fixed organic carbon. Sequencing of 16S ribosomal RNA genes extracted from soil cores revealed a significant increase in the relative abundance of Polaromonas, a known hydrocarbon-degrader, following exposure to both types of oil. This study demonstrates that in the first several months following a surface spill, dilbit has a similar potential for biodegradation by a native shallow subsurface microbial community as conventional heavy crude oil.


Assuntos
Petróleo , Poluentes Químicos da Água , Campos de Petróleo e Gás , Poluentes Químicos da Água/análise , Ácidos Graxos , Hidrocarbonetos/metabolismo , Carbono , Solo
10.
ACS Appl Bio Mater ; 6(3): 1173-1184, 2023 03 20.
Artigo em Inglês | MEDLINE | ID: mdl-36795958

RESUMO

We designed, synthesized, and characterized a Raman nanoprobe made of dye-sensitized single-walled carbon nanotubes (SWCNTs) that can selectively target biomarkers of breast cancer cells. The nanoprobe is composed of Raman-active dyes encapsulated inside a SWCNT, whose surface is covalently grafted with poly(ethylene glycol) (PEG) at a density of ∼0.7% per carbon. Using α-sexithiophene- and ß-carotene-derived nanoprobes covalently bound to an antibody, either anti-E-cadherin (E-cad) or anti-keratin-19 (KRT19), we prepared two distinct nanoprobes that specifically recognize biomarkers on breast cancer cells. Immunogold experiments and transmission electron microscopy (TEM) images are first used to guide the synthesis protocol for higher PEG-antibody attachment and biomolecule loading capacity. The duplex of nanoprobes was then applied to target E-cad and KRT19 biomarkers in T47D and MDA-MB-231 breast cancer cell lines. Hyperspectral imaging of specific Raman bands allows for simultaneous detection of this nanoprobe duplex on target cells without the need for additional filters or subsequent incubation steps. Our results confirm the high reproducibility of the nanoprobe design for duplex detection and highlight the potential of Raman imaging for advanced biomedical applications in oncology.


Assuntos
Nanotubos de Carbono , Neoplasias , Reprodutibilidade dos Testes , Biomarcadores , Polietilenoglicóis , Anticorpos , Fenótipo
11.
Chemosphere ; 313: 137376, 2023 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-36436585

RESUMO

A bioinspired device was fabricated as a sustainable remedial method and its performance as a membrane-enzyme reactor with cyclic ultrafiltration was investigated. The body of the jellyfish-like device was composed of two parts: 1) Jellyfish arms: Mono and co-axial electrospinning have been utilized to synthesize the flexible parts (e.g., multilayer membrane PS-PVDF/PAN/PS-PVDF) used for immobilization of aliphatic degrading enzymes, and 2) Jellyfish tentacles: Hollow fiber membranes were selected for physical immobilization of polycyclic aromatic hydrocarbon (PAH) degrading enzymes. To study the behavior of the membrane/enzyme reactor, the hollow fiber enzyme reactor with pulsation was operated by recycling an enzyme solution to assess ultrafiltration efficiency. A mathematical model was suggested to describe the experimental data obtained in this study to predict the effectiveness of the reactor for PAH removal. When testing the performance of the jellyfish-like device, those equipped with nanofibers with an oil sorption capacity of (10. ±0.7gdilbit/gfiber) were more effective at removing oil particles before they touched the hollow fiber membrane surface. Moreover, the reaction rate measured in a free soluble enzyme and a recirculating immobilized enzyme solution exhibited a slight difference in the kinetic parameter, Km (0.03 and 0.021 mM) due to the internal diffusional resistance. Based on biodegradation studies, a synergistic effect between membrane adsorption, enzymatic degradation, and ultrafiltration was proposed for the removal of anthracene from the column of water.


Assuntos
Hidrocarbonetos Policíclicos Aromáticos , Água , Biodegradação Ambiental , Reatores Biológicos , Enzimas Imobilizadas/metabolismo , Hidrocarbonetos Policíclicos Aromáticos/análise
12.
J Hazard Mater ; 434: 128777, 2022 07 15.
Artigo em Inglês | MEDLINE | ID: mdl-35462124

RESUMO

The use of surfactant foam for the remediation of diesel fuel, a Light Non-Aqueous Phase Liquid (LNAPL), was investigated in sand column experiments using X-ray Computed Tomography (CT). A preliminary series of tests were carried out on six surfactant candidates in order to measure their physical properties, including critical micelle concentrations and interfacial tensions (IFT) with the LNAPL. Batch tests for foam stability were carried out with and without added LNAPL, in order to measure the half-life of foam columns produced with each surfactant candidate. Foam flow-rate co-injection tests were carried out for each surfactant candidate in 405 cm3 sand columns contaminated with LNAPL at residual saturation. These tests revealed that a 1:1 mixture of sodium dodecyl sulfate and cocamidopropyl betaine, injected at a total volumetric flow-rate (Qfoam) of 45 mL/min, resulted in successful generation and propagation of foam within the contaminated porous medium. Finally, two sand column tests, carried out respectively under high- and low-pressure conditions, were imaged with a CT-scanner in order to compare and contrast foam morphology evolution as well as the LNAPL desaturation dynamics involved in both scenarios. The saturation profiles extracted from CT images provided valuable new insights.


Assuntos
Poluentes do Solo , Solo , Aerossóis , Gasolina , Areia , Poluentes do Solo/análise , Tensoativos , Tomografia Computadorizada por Raios X
13.
Nano Lett ; 22(7): 2635-2642, 2022 04 13.
Artigo em Inglês | MEDLINE | ID: mdl-35352961

RESUMO

As graphene field-effect transistors (GFETs) are becoming increasingly valued for sensor applications, efficiency and control of their surface functionalization become critical. Here, we introduce an innovative method using a gate electrode to precisely modulate aryldiazonium functionalization directly on graphene devices. Although this covalent chemistry is well-known, we show that its spontaneous reaction on GFETs is highly heterogeneous with a low overall yield. By dynamically tuning the gate voltage in the presence of the reactant, we can quickly enable or suppress the reaction, resulting in a high degree of homogeneity between devices. We are also able to monitor and control functionalization kinetics in real time. The mechanism for our approach is based on electron transfer availability, analogous to chemical, substrate-based, or electrochemical doping, but has the practical advantage of being fully implementable on devices or chips. This work illustrates how powerful the FET platforms are to study surface reactions on nanomaterials in real time.


Assuntos
Grafite , Nanoestruturas , Eletrodos , Transporte de Elétrons , Transistores Eletrônicos
14.
Nano Lett ; 22(7): 2851-2858, 2022 Apr 13.
Artigo em Inglês | MEDLINE | ID: mdl-35311277

RESUMO

Black phosphorus (BP) is unique among layered materials because of its homonuclear lattice and strong structural anisotropy. While recent investigations on few-layer BP have extensively explored the in-plane (a, c) anisotropy, much less attention has been given to the out-of-plane direction (b). Here, the optical response from bulk BP is probed using polarization-resolved photoluminescence (PL), photoluminescence excitation (PLE), and resonant Raman scattering along the zigzag, out-of-plane, and armchair directions. An unexpected b-polarized luminescence emission is detected in the visible, far above the fundamental gap. PLE indicates that this emission is generated through b-polarized excitation at 2.3 eV. The same electronic resonance is observed in resonant Raman with the enhancement of the Ag phonon modes scattering efficiency. These experimental results are fully consistent with DFT calculations of the permittivity tensor elements and demonstrate the remarkable extent to which the anisotropy influences the optical properties and carrier dynamics in black phosphorus.

15.
J Hazard Mater ; 423(Pt A): 127099, 2022 02 05.
Artigo em Inglês | MEDLINE | ID: mdl-34523486

RESUMO

Enzymatic bioremediation is a sustainable and environment-friendly method for the clean-up of contaminated soil and water. In the present study, enzymatic bioremediation was designed using cold-active enzymes (psychrozymes) which catalyze oxidation steps of p-xylene biodegradation in highly contaminated soil (initial concentration of 13,000 mg/kg). The enzymes were obtained via co-culture of two psychrophilic Pseudomonas strains and characterized by kinetic studies and tandem LC-MS/MS. To mimic in situ application of enzyme mixture, bioremediation of p-xylene contaminated soil was carried out in soil column (140 mL) tests with the injection (3 pore volume) of different concentrations of enzyme cocktails (X, X/5, and X/10). Enzyme cocktail in X concentration contained about 10 U/mL of xylene monooxygenase (XMO) and 20 U/mL of catechol 2, 3 dioxygenases (C2,3D). X/5 and X/10 correspond to 5x and 10x dilution of enzyme cocktail respectively. The results showed that around 92-94% p-xylene removal was achieved in the treated soil column with enzyme concentration X, X/5 after second enzyme injection. While the p-xylene removal rate obtained by X/10 concentration of enzyme was less than 30% and near to untreated soil column (22.2%). The analysis of microbial diversity and biotoxicity assay (root elongation and seed germination) confirmed the advantage of using enzymes as a green and environmentally friendly approach for decontamination of pollutants with minimal or even positive effects on microbial community and also enrichment of soil after treatment.


Assuntos
Poluentes do Solo , Solo , Biodegradação Ambiental , Cromatografia Líquida , Cinética , Microbiologia do Solo , Poluentes do Solo/análise , Espectrometria de Massas em Tandem , Xilenos
16.
Environ Sci Pollut Res Int ; 29(15): 21465-21479, 2022 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-34762239

RESUMO

p-Xylene is considered a recalcitrant compound despite showing a similar aromatic structure to other BTEXs (benzene, toluene, ethylbenzene, xylene isomers). This study evaluated the p-xylene biodegradation potential of three psychrophilic Pseudomonas strains (Pseudomonas putida S2TR-01, Pseudomonas synxantha S2TR-20, and Pseudomonas azotoformans S2TR-09). The p-xylene metabolism-related catabolic genes (xylM, xylA, and xylE) and the corresponding regulatory genes (xylR and xylS) of the selected strains were investigated. The biodegradation results showed that the P. azotoformans S2TR-09 strain was the only strain that was able to degrade 200 mg/L p-xylene after 60 h at 15 °C. The gene expression study indicated that the xylE (encoding catechol 2,3-dioxygenase) gene represents the bottleneck in p-xylene biodegradation. A lack of xylE expression leads to the accumulation of intermediates and the inhibition of biomass production and complete carbon recovery. The activity of xylene monooxygenase and catechol 2,3-dioxygenase was significantly increased in P. azotoformans S2TR-09 (0.5 and 0.08 U/mg, respectively) in the presence of p-xylene. The expression of the ring cleavage enzyme and its encoding gene (xylE) and activator (xylS) explained the differences in the p-xylene metabolism of the isolated bacteria and can be used as a novel biomarker of efficient p-xylene biodegradation at contaminated sites.


Assuntos
Pseudomonas putida , Xilenos , Biodegradação Ambiental , Expressão Gênica , Pseudomonas/genética , Pseudomonas/metabolismo , Pseudomonas putida/metabolismo , Tolueno/metabolismo , Xilenos/metabolismo
17.
Environ Pollut ; 290: 117986, 2021 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-34523511

RESUMO

Though many studies pertaining to soil bioremediation have been performed to study the microbial kinetics in shake flasks, the process efficiency in column tests is seldom. In the present study, soil columns tests were carried out to study the biodegradation of soil contaminated with a high concentration of diesel (≈19.5 g/kg) petroleum hydrocarbons expressed as C10-C50. Experiments were done with crude enzymatic cocktail produced by the hydrocarbonoclastic bacterium, Alcanivorax borkumensis. A. borkumensis was grown on a media with 3% (v/v) motor oil as the sole carbon and energy source. The effects of the enzyme concentration, treatment time and oxidant on the bioremediation efficiency of C10-C50 were investigated. A batch test was also carried out in parallel to investigate the stability of the enzymes and the effect of the biosurfactants on the desorption and the bioconversion of C10-C50. Batch tests indicated that the biosurfactants significantly affected the desorption and alkane hydroxylase and lipase enzymes, maintained their catalytic activity during the 20-day test, with a half-life of 7.44 days and 8.84 days, respectively. The crude enzyme cocktail, with 40 U/mL of lipase and 10 U/mL of alkane hydroxylase, showed the highest conversion of 57.36% after 12 weeks of treatment with a degradation rate of 0.0218 day-1. The results show that the soil column tests can be used to optimize operating conditions for hydrocarbon degradation and to assess the performance of the overall bioremediation process.


Assuntos
Alcanivoraceae , Petróleo , Poluentes do Solo , Biodegradação Ambiental , Hidrocarbonetos , Solo , Microbiologia do Solo , Poluentes do Solo/análise
18.
Environ Pollut ; 285: 117678, 2021 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-34380234

RESUMO

Toluene/o-Xylene Monooxygenase (ToMO) is equipped with a broad spectrum of aromatic substrate specificity (such as BTEX; benzene, toluene, ethylbenzene, and isomers of xylenes). TOMO has can hydroxylate more than a single position of aromatic rings in two consecutive monooxygenation reactions. Catechol 1,2-dioxygenase (C1,2D) is an iron-containing enzyme able to cleave the ring of catechol (the converted product from ToMO) for complete detoxification of BTEX. In this study, cold-active ToMO and C1,2D were produced using newly isolated psychrophilic Pseudomonas S2TR-14 in the minimal salt medium supplemented with crustacean waste and different concentrations of used motor oil (0.2-2% (v/v)). Crude ToMO and C1,2D were immobilized into micro/nano biochar-chitosan matrices and used for BTEX biodegradation. The results showed that the highest enzyme production (12 U/mg for ToMO and 22 U/mg for C1,2D) was achieved at the presence of 0.5% v/v used motor oil compared to the control group without motor oil (0.07 and 0.06 U/mg). High immobilization yield was achieved due to covalent bonding of ToMO (92.26% for micro matrix and 77.20% for nano matrix) and C1,2D (87.57% for micro matrix and 74.79% for nano matrix) with matrices. FTIR spectra confirmed the immobilization of enzymes on the surface of microbiochar and nanobiochar-chitosan matrices as proper support. The immobilization increased the storage stability of the enzymes with more than 50% residual activity after 30 days at 4 ± 1 °C, while the free form of enzymes had less than 10% of its activity. Immobilized enzymes degraded more than 80% of BTEX (~200 mg/L in groundwater and ~10,000 mg/kg in soil) at 10 ± 1 °C in groundwater and soil. Therefore, integrated use of microbiochar and nanobiochar with chitosan for co-immobilization of ToMO and C1,2D can be a potential way to remove petroleum hydrocarbons with higher efficiency from contaminated groundwater and soil.


Assuntos
Pseudomonas , Xilenos , Benzeno , Derivados de Benzeno , Biodegradação Ambiental , Tolueno
19.
Bioresour Technol ; 321: 124464, 2021 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-33302008

RESUMO

Sites contaminated by petroleum hydrocarbons in cold-climate regions have recently received significant attention due to their sensitive ecosystem and human health impacts. Two cold-adapted pseudomonas strains were isolated from contaminated groundwater and soil. As xylene monooxygenase from Pseudomonas synxantha S2TR-26 and catechol 2,3-dioxygenase from Pseudomonas mandelii S2TR-08, have a matching end product, they acted in symphony to degrade p-xylene. Their unique thermodynamic and kinetic behavior permits them to achieve rapid degradation of p-xylene at low temperatures (<15 °C). The results showed that the sequential action led to the conversion of 200 mg/l of p-xylene within 72 h and complete degradation after 120 h. The cocktail of these enzymes with a ratio of 1:1.5 (xylene monooxygenase: catechol 2, 3-dioxygenase) confirmed the complete degradation of p-xylene within 48 h at 15 °C. This approach will allow efficient biodegradation of p-xylene to minimize the bioremediation duration in cold-climate regions.


Assuntos
Água Subterrânea , Petróleo , Poluentes do Solo , Biodegradação Ambiental , Clima Frio , Ecossistema , Humanos , Pseudomonas , Xilenos
20.
Klin Padiatr ; 232(6): 285-288, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32937669

RESUMO

At the age of 4 months, an infant was presented to us with a nodular subcutaneous tumor on the right thumb measuring 2cm, already seen prenatally via ultrasound. An MRI in sedation performed at the age of 4.5 months had no diagnostic specificity. By a biopsy at the age of 5 months malignancy could be excluded. Finally at the age of 16 months the tumor which had meanwhile grown to a monstrous size (5 cm of diameter) could be entirely removed by microsurgical technique maintaining the integrity of all intrinsic structures. The diagnosis of myxoid lipoblastoma was confirmed. According to literature, Lipoblastomas often present as connatal rapid growing soft tissue tumors and are benign. Total removal is essential for avoiding a local recurrence.


Assuntos
Proteínas de Ligação a DNA/genética , Lipossarcoma Mixoide/genética , Lipossarcoma Mixoide/cirurgia , Neoplasias de Tecidos Moles/cirurgia , Biópsia , Proteínas de Ligação a DNA/metabolismo , Humanos , Lactente , Lipossarcoma Mixoide/patologia , Imageamento por Ressonância Magnética , Recidiva Local de Neoplasia , Neoplasias de Tecidos Moles/patologia , Polegar/diagnóstico por imagem , Fatores de Transcrição , Resultado do Tratamento
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