Silver, copper and copper oxide nanoparticles in the fight against human viruses: progress and perspectives.

The rapid development of nanomedicine has created a high demand for silver, copper and copper oxide nanoparticles. Due to their high reactivity and potent antimicrobial activity, silver and copper-based nanomaterials have been playing an important role in the search for new alternatives for the treatment of several issues of concern, such as pathologies caused by bacteria and viruses. Viral diseases are a significant and constant threat to public health. The most recent example is the pandemic caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). In this context, the object of the present review is to highlight recent progress in the biomedical uses of these metal nanoparticles for the treatment and prevention of human viral infections. We discuss the antiviral activity of AgNPs and Cu-based NPs, including their actions against SARS-CoV-2. We also discuss the toxicity, biodistribution and excretion of AgNPs and CuNPs, along with their uses in medical devices or on inert surfaces to avoid viral dissemination by fomites. The challenges and limitations of the biomedical use of these nanoparticles are presented.

Hemosiderosis pulmonar idiopática: seguimiento de pacientes durante 25 años (1995-2019) / Idiopathic pulmonary hemosiderosis: follow-up of patients for 25 years (1995-2019)

La hemosiderosis pulmonar idiopática (HPI) es una causa de hemorragia alveolar difusa. OBJETIVO: describir la evolución de niños con HPI en nuestra institución. Se realizó una revisión retrospectiva con protocolo de seguimiento. Se reclutaron 13 pacientes, 7 hombres. Procedentes de una zona agrícola (6/13). No todos presentaron la tríada diagnóstica completa: infiltrados algodonosos (9/13), anemia (11/13), hemoptisis (9/13). Todos evidenciaron un recuento de hemosiderófagos sobre 30% en el lavado broncoalveolar. Tomografía computada de tórax: normal (5/13), patrón intersticial (5/13), vidrio esmerilado (2/13) y fibrosis (1/13). Espirometría: normal (7/13), restrictiva (4/13), obstructiva (1/13) y no efectuada (1/13). Tratamiento durante la fase aguda: bolos de metilprednisolona (7/13) o prednisona (6/13) o hidrocortisona (1/13). En la fase de mantención se administró: prednisona (13/13) más un inmunosupresor, azathioprina (12/13), hidroxicloroquina (1/13), micofenolato (1/13), más budesonida MDI (13/13). Ocho pacientes detuvieron los sangrados. Dos pacientes fallecieron y hubo cinco embarazos de curso fisiológico en 3 adolescentes. Se observó: a) diferentes modalidades de presentación que retrasaron el diagnóstico; b) gran exposición a pesticidas; c) mejor pronóstico si el diagnóstico y el tratamiento eran precoces, también en niñas adolescentes; d) la mayoría detuvo los episodios de sangrado.

Idiopathic pulmonary hemosiderosis (IPH) is a cause of diffuse alveolar hemorrhage. OBJECTIVE: to describe the evolution of children with IPH in our institution. Retrospective monitoring with a follow-up protocol was carried out. 13 patients, seven males, were recruited. From an agricultural area (6/13). Not all of patients had the complete diagnostic triad: cotton infiltrates (9/13), anemia (11/13), hemoptysis (9/13). Hemosiderin-laden macrophages counting in the bronchoalveolar lavage fluid was over 30% in all the patients. Computed chest tomography was informed as normal (5/13), interstitial pattern (5/13), ground glass (2/13) and fibrosis (1/13). Spirometry: normal (7/13), restrictive (4/13), obstructive (1/13) and not performed (1/13). Treatment during the acute phase: bolus of methylprednisolone (7/13) or prednisone (6/13) or hydrocortisone (1/13). In the maintenance phase: prednisone (13/13) plus an immunosuppressant, azathioprine (12/13), hydroxychloroquine (1/13), mycophenolate (1/13), plus budesonide MDI (13/13). Eight patients stopped the bleeding episodes. Two patients died and there were five physiological pregnancies in 3 adolescents. It was observed:(a) different modes of IPH presentation that delayed its diagnosis; (b) large exposure to pesticides; (c) prognosis improved if diagnosis and treatment were early, also in adolescent girls; (d) most of the patients stopped the bleeding episodes.

Agenesia unilateral de la arteria pulmonar: presentación de dos casos y revisión de la literatura / Unilateral agenesis pulmonary artery: presentation of two cases and review of the literature

Unilateral agenesis of the pulmonary artery is a rare malformation, sometimes asymptomatic and underdiagnosed. Right agenesis is usually isolated, while the left agenesis is more frequently associated with cardiovascular malformations. Some patients have recurrent respiratory infections, exercise limitation, hemoptysis, and/or pulmonary hypertension. The diagnosis is suspected by chest radiograph showing a hypoplastic lung ipsilateral to the agenesis. It is confirmed with contrast-enhanced chest computed tomography. In asymptomatic patients, management should be conservative, however, the search for collateral vessels should be started from adolescence, because they can bleed. In symptomatic patients or those with serious complications, the treatment must be interventional. The objective of this article is to present two patients with right and left pulmonary artery agenesis respectively and review the literature.

La agenesia unilateral de la arteria pulmonar es una malformación poco frecuente, en ocasiones asintomática y subdiagnosticada. La agenesia derecha suele ser aislada, en cambio la izquierda se asocia más frecuentemente a malformaciones cardiovasculares. Algunos pacientes presentan infecciones respiratorias recurrentes, limitación al ejercicio, hemoptisis y/o hipertensión pulmonar. El diagnóstico se sospecha al solicitar una radiografía de tórax que muestra un pulmón hipoplásico ipsilateral a la agenesia. Se confirma con tomografía computada de tórax con contraste. En pacientes asintomáticos el manejo debe ser conservador, sin embargo, se debe iniciar la búsqueda de vasos colaterales especialmente durante la adolescencia, los que pueden sangrar. En cambio, en los pacientes sintomáticos o que presentan complicaciones graves, el tratamiento debe ser intervencional. El objetivo de este trabajo es presentar a dos pacientes con agenesia de la arteria pulmonar derecha e izquierda respectivamente y hacer una revisión de la literatura.

Silver nanoparticles: Toxicity in model organisms as an overview of its hazard for human health and the environment.

Silver nanoparticles (AgNPs) have attracted remarkable attention due to their powerful antimicrobial action as well as their particular physicochemical properties. This has led to their application in a wide variety of products with promising results. However, their interaction with the environment and toxicity in live terrestrial or aquatic organisms is still a matter of intense debate. More detailed knowledge is still required about the toxicity of AgNPs, their possible uptake mechanisms and their adverse effects in live organisms. Several studies have reported the interactions and potential negative effects of AgNPs in different organisms. In this review, we report and discuss the current state of the art and perspectives for the impact of AgNPs on different organisms present in the environment. Recent progress in interpreting uptake, translocation and accumulation mechanisms in different organisms and/or living animals are discussed, as well as the toxicity of AgNPs and possible tolerance mechanisms in live organisms to cope with their deleterious effects. Finally, we discuss the challenges of accurate physicochemical characterization of AgNPs and their ecotoxicity in environmentally realistic conditions such as soil and water media.

Short term changes in the abundance of nitrifying microorganisms in a soil-plant system simultaneously exposed to copper nanoparticles and atrazine.

Copper nanoparticles (NCu) may co-exist with other pollutants in agricultural soils, such as pesticides. However, this has been little evaluated yet. Thus, possible effects of the simultaneous applications of pesticides and NCu on biogeochemical cycles are expected, for example on the nitrogen cycle. Therefore, the aim of this work was to evaluate the effect of simultaneous application of the herbicide atrazine (ATZ) and NCu on the abundance of total bacteria and nitrifying communities: ammonia-oxidizing archaea (AOA) and ammonia-oxidizing bacteria (AOB). Moreover, the ATZ dissipation was evaluated. A soil-plant system containing ATZ at field dose (3 mg a.i. kg-1) was mixed with two doses of NCu (0.05% or 0.15% w/w). Changes in the abundance of 16S rRNA and ammonia monooxygenase (amoA) genes of AOA and AOB were evaluated by real-time quantitative PCR (qPCR) at three sampling times (1, 15 and 30 days). The residual ATZ and nitrate production were also measured. The results showed significant differences in microbial composition and abundance over the 30 days of the experiment. Particularly, an initial decrease was observed in total bacterial abundance due to the presence of ATZ and NCu respect to ATZ alone (~60%). The abundance of AOA was also remarkably reduced (~85%), but these communities gradually recovered towards the end of the experiment. Conversely, AOB abundance initially increased (>100%) and remained mainly unaltered in soil exposed to ATZ and NCu 0.15% w/w, where nitrate formation was also constant. Moreover, NCu decreased the ATZ dissipation, which was translated in a 2-fold increase on the ATZ half-life values (T1/2). This study demonstrates that the simultaneous presence of NCu and ATZ may represent a risk for the total bacteria present in soil and sensitive microorganisms such as nitrifying communities, and changes in the dissipation of the pesticide could influence this process.

Combined pollution of copper nanoparticles and atrazine in soil: Effects on dissipation of the pesticide and on microbiological community profiles.

Copper nanoparticles (NCu) have been proposed as an antimicrobial agent in agriculture. Therefore, NCu may interact with numerous pollutants including pesticides. Little is known about the combined effects of NCu and pesticides in soil. This study aimed at assessing the impact of NCu combined with the herbicide atrazine (ATZ) on soil. We focused on assessing the adsorption and dissipation of ATZ in the presence of NCu and the changes in microbial community profiles. First, ATZ adsorption isotherms (described using the Freundlich equation) were evaluated. After that, soil samples were spiked with NCu (40-60 nm) at 0.05 and 0.15% w/w and ATZ (3 mg a.i kg-1) and incubated for 30 days. The results showed that ATZ adsorption is favored by the presence of NCu. On the other hand, NCu at 0.15% w/w caused a significant decrease in ATZ dissipation, increasing its half-life from 6 to 37 days. Microbial community profiles (bacteria, fungi and nitrifying bacteria) remained relatively stable throughout the evaluated period. Therefore, our findings suggest that NCu can increase the persistence of ATZ in soil, which may be mostly associated to physical-chemical interaction with soil particles more than a microbial impact.

The nanotechnology among US: are metal and metal oxides nanoparticles a nano or mega risk for soil microbial communities?

Metal nanoparticles and metal oxides nanoparticles (MNPs/MONPs) have been widely included in a great diversity of products and industrial applications and they are already a part of our everyday life. According to estimation studies, their production is expected to increase exponentially in the next few years. Consequently, soil has been suggested as the main sink of MNPs/MONPs once they are deliberately or accidentally released into the environment. The potential negative perturbations that may result on soil microbial communities and ecological processes are resulting in concerns. Several nano-toxicological studies of MNPs/MONPs, reported so far, have focused on aquatic organisms, animals, and soil invertebrates. However, during recent years, the studies have been oriented to understand the effects of MNPs/MONPs on microbial communities and their interaction with soil components. The studies have suggested that MNPs/MONPs are one of the most toxic type to soil biota, amongst different types of nanomaterials. This may threaten soil health and fertility, since microbial communities are known to support important biological processes and ecosystem services such as the nutrient cycling, whereby their protection against the environmental pollution is imperative. Therefore, in this review we summarize the actual knowledge available from the last five years (2013-2018) and gaps about the potential negative, positive or neutral effects produced on soil by different classes of MNPs/MONPs. A particular emphasis has been placed on the associated soil microorganisms and biological processes. Finally, perspectives about future research are discussed.

Bronquiolitis obliterante secundaria a sindrome de stevens-johnson. Presentacion de 2 casos y revision de la literatura / Obliterans bronchiolitis secondary to stevens-johnson syndrome: case reports

Stevens-Johnson syndrome corresponds to a hypersensitivity reaction produced by various etiologies, for example exposure to drugs, microbial agents, or by an idiopathic cause. It is marked by an acute vesicular-bullous eruption, which affects the skin and mucous membranes, with systemic manifestations of variable severity, and it may present a fatal evolution. Stevens-Johnson syndrome can occasionally present chronic pulmonary complications, such as bronchiolitis obliterans; however, other etiologies are more frequent in our environment, for example severe pneumonia due to adenovirus. Our objective is to present two cases of bronchiolitis obliterans post Stevens-Johnson syndrome and to make a literature review.

El síndrome de Stevens-Johnson corresponde a una respuesta de hipersensibilidad producida por diversas etiologías, que incluyen exposición a drogas, agentes microbianos o idiopática. Se manifiesta por una erupción vesículo-bulosa aguda, que afecta la piel y las mucosas, con manifestaciones sistémicas de severidad variable, pudiendo presentar una evolución fatal. El síndrome de Stevens-Johnson puede presentar ocasionalmente complicaciones pulmonares crónicas, como bronquiolitis obliterante, siendo en nuestro medio más frecuente otras etiologías, como la observada luego de una neumonía grave por adenovirus. El objetivo es presentar dos casos de bronquiolitis obliterante post síndrome de Stevens-Johnson y hacer una revisión de la literatura.

Pesticide dissipation and microbial community changes in a biopurification system: influence of the rhizosphere.

The dissipation of atrazine, chlorpyrifos and iprodione in a biopurification system and changes in the microbial and some biological parameters influenced by the rhizosphere of Lolium perenne were studied in a column system packed with an organic biomixture. Three column depths were analyzed for residual pesticides, peroxidase, fluorescein diacetate activity and microbial communities. Fungal colonization was analyzed by confocal laser scanning microscopy to assess the extent of its proliferation in wheat straw. The L. perenne rhizosphere enhanced pesticide dissipation and negligible pesticide residues were detected at 20-30 cm column depth. Atrazine, chlorpyrifos and iprodione removal was 82, 89 and 74% respectively in the first 10 cm depth for columns with vegetal cover. The presence of L. perenne in contaminated columns stimulated peroxidase activity in all three column depth sections. Fluorescein diacetate activity decreased over time in all column sections with the highest values in biomixtures with vegetal cover. Microbial communities, analyzed by PCR-DGGE, were not affected by the pesticide mixture application, presenting high values of similarity (>65%) with and without vegetal cover. Microbial abundance of Actinobacteria varied according to treatment and no clear link was observed. However, bacterial abundance increased over time and was similar with and without vegetal cover. On the other hand, fungal abundance decreased in all sections of columns after 40 days, but an increase was observed in response to pesticide application. Fungal colonization and straw degradation during pesticide dissipation were verified by monitoring the lignin autofluorescence loss.

Production of ligninolytic enzymes and some diffusible antifungal compounds by white-rot fungi using potato solid wastes as the sole nutrient source.

AIMS: The aim of this study was to evaluate the synthesis of ligninolytic enzymes and some diffusible antifungal compounds by white-rot fungi (WRF) using peels or discarded potato as the sole nutrient source. METHODS AND RESULTS: The strain Trametes hirsuta Ru-513 highlighted for its laccase activity (595 ± 33 U l-1 ), which is able to decolourize 87% of an anthraquinone dye using potato peels as the sole nutritional support. A native polyacrylamide gel of laccase proteins showed the presence of two isoenzymes, corresponding to proteins of 56 and 67 kDa, which were detected by SDS-PAGE. The antifungal activity of ethyl acetate extracts was evaluated by the agar diffusion method, where Anthracophyllum discolor Sp4 and Inonotus sp. Sp2 showed the highest inhibition zones of Mucor miehei. The fungal extracts also inhibited Fusarium oxysporum and Botrytis cinerea growth, with inhibition zones of up to 18 mm. The extract with the highest antifungal activity, from A. discolor Sp4 grown in discarded potato medium, was analysed using a gas chromatograph coupled to a mass spectrometer. Among the identified compounds, chlorinated aromatic compounds and veratryl alcohol were the most abundant compounds. CONCLUSIONS: The results revealed the relevance of potato waste valorization for the sustainable production of ligninolytic enzymes and antifungal compounds. SIGNIFICANCE AND IMPACT OF THE STUDY: This study reports the synthesis of ligninolytic enzymes and diffusible antifungal compounds by WRF using potato wastes as the sole nutrient source and suggests a relationship between the enzymatic activity and the synthesis of antifungal compounds. These compounds and the synthesis of halogen compounds by WRF using agro-industrial wastes have been poorly studied before.

Anillos vasculares en pediatria: presentación de 2 casos / Pediatric vascular rings: case reports

Vascular rings are uncommon congenital anomalies that result from anomalous embryological development of the mediastinum main arteries (aortic arch and its branches, pulmonary artery). Such anomalous vascular structures may produce compression of the trachea and / or esophagus, with consequent obstructive respiratory and digestive symptoms. Vascular rings can be complete or incomplete. They can be asymptomatic or manifest with persistent or recurrent respiratory and / or digestive symptoms. The study should include chest X-ray, barium swallow, flow-volume loop, fiberoptic bronchoscopy, chest computed tomography, angiotomography or magnetic resonance. Symptomatic patients often need surgery

Los anillos vasculares son el resultado de anomalías del desarrollo embrionario de grandes troncos vasculares del mediastino, tanto del cayado aórtico y sus ramas, como de la arteria pulmonar. Dichas estructuras vasculares anómalas pueden producir compresión de la tráquea y/o del esófago, con la consiguiente sintomatología obstructiva respiratoria y digestiva. En algunas ocasiones forman un anillo completo y en otras incompleto. El diagnóstico puede ser casual cuando son silentes o resultado del estudio de síntomas respiratorios y/o digestivos persistentes o recurrentes. El estudio debe incluir radiografía de tórax, esofagograma, curva flujo/volumen, fibrobroncoscopía, angiotomografía computada o angioresonancia magnética de tórax. En pacientes sintomáticos se debe recurrir a la cirugía, en cambio los asintomáticos u oligosintomáticos deben ser observados

Neumotórax espontáneo debido a bulas subpleurales: presentacion de un caso / Spontaneous pneumothorax and subpleural bulla: case report

Pneumothorax is defined as the presence of air within the pleural cavity. It may be traumatic, iatrogenic, spontaneous secondary or primary. In the latter cause, the most frequent are subpleural and apical bulla in longiline patients, with connective tissue diseases and smokers. Treatment should be conservative in patients who present a small pneumothorax. Instead, a probe should be installed if it is greater. In the presence of frequent recurrences or persistent air leakage, pleurodesis should be considered, or resection of the bullous should be practiced. In this article we review a patient with Elhers Danlos syndrome, who presents a primary spontaneous pneumothorax due to subpleural bulla

El neumotórax se define como la presencia de aire dentro de la cavidad pleural. Puede ser traumático, iatrogénico, espontáneo secundario o primario, dentro de esta última causa la más frecuente son las bulas subpleurales y apicales, en pacientes longilíneos, portadores de enfermedades del tejido conectivo y fumadores. En neumotórax pequeños el tratamiento debe ser conservador, en cambio en los de mayor cuantía se debe proceder a la instalación de una sonda pleural. Frente a recidivas frecuentes o persistencia del escape aéreo, se debe considerar la pleurodesis o bien practicar la resección de las bulas.En el presente artículo se reporta a un paciente con síndrome de Elhers Danlos que presenta un neumotórax espontáneo primario debido a bulas subpleurales.

Increased diazinon hydrolysis to 2-isopropyl-6-methyl-4-pyrimidinol in liquid medium by a specific Streptomyces mixed culture.

Actinobacteria identified as Streptomyces spp. were evaluated for their ability to remove diazinon as the only carbon source from a liquid medium. Single cultures of Streptomyces strains were exposed to diazinon at a concentration of 50 mg L(-1). After 96 h incubation, six of the eight cultures grew and five strains showed an increase in their total protein concentrations and changes in their protein profile. Up to 32% of the diazinon was removed by the single Streptomyces cultures. A compatibility assay showed that the different Streptomyces species were not antagonistic. Twenty-six mixed cultures were then prepared. Diazinon removal was increased when mixed cultures were used, and maximum diazinon removal of 62% was observed when the Streptomyces spp. strains AC5, AC9, GA11 and ISP13 were mixed; this was defined as the selected mixed culture (SMC). Diazinon removal was positively influenced by the addition of glucose into the liquid medium. Our study showed a diazinon degradation rate of 0.025 h(-1), half-life of 28 h(-1) and 2-isopropyl-6-methyl-4-pyrimidinol (IMHP) production of 0.143 mg L h(-1). Rapid diazinon hydrolysis to IMHP was associated with a decrease in the pH of the medium as a consequence of microbial glucose metabolism and organic acid exudation. Moreover, the SMC of Streptomyces was able to remove IMHP. This work constitutes a new, if not the only, report on diazinon degradation by mixed cultures of Streptomyces spp. Given the high levels of diazinon removal, the SMC formed by four Streptomyces strains has the potential to be used to treat the diazinon present in environmental matrices.

Hernia diafragmática en pediatría / Diaphragmatic hernia in children

The diaphragmatic hernia is a disorder in the development of the diaphragm, causing the passage of the abdominal contents into the thoracic cavity. The main ones are Bochdalek, hiatal and Morgagni hernias. Prenatal ultrasound determines the diagnosis, prognosis and therapy. Lately nuclear magnetic resonance is being used. The surgical procedure consists of the closure of the defect and correcting the intestinal malrotation. The goal of the treatment is to maintain adequate gas exchange and to prevent or minimize hypoplasia and pulmonary hypertension. This article discusses the diagnosis and management of the various forms of diaphragmatic hernia.

La hernia diafragmática (HD) consiste en un trastorno en el desarrollo del músculo diafragmático, produciéndose el paso de contenido abdominal a la cavidad torácica. Las principales son hernia de Bochdalek, Morgagni y hiatal. La ecografía prenatal determina el diagnóstico, pronóstico y terapia, últimamente se está utilizado la resonancia nuclear magnética. La cirugía consiste en cerrar el defecto y corregir la malrotación intestinal, siendo el objetivo del tratamiento mantener un adecuado intercambio gaseoso y evitar o minimizar la hipoplasia y la hipertensión pulmonar. En este artículo se revisa el diagnóstico y manejo de las diferentes modalidades de hernia diafragmática.

Fungal volatiles: an environmentally friendly tool to control pathogenic microorganisms in plants.

Fungi are an extraordinary and immensely diverse group of microorganisms that colonize many habitats even competing with other microorganisms. Fungi have received recognition for interesting metabolic activities that have an enormous variety of biotechnological applications. Previously, volatile organic compounds produced by fungi (FVOCs) have been demonstrated to have a great capacity for use as antagonist products against plant pathogens. However, in recent years, FVOCs have been received attention as potential alternatives to the use of traditional pesticides and, therefore, as important eco-friendly biotechnological tools to control plant pathogens. Therefore, highlighting the current state of knowledge of these fascinating FVOCs, the actual detection techniques and the bioactivity against plant pathogens is essential to the discovery of new products that can be used as biopesticides.

Cuerpo extraño en la vía aérea en pediatría / Foreign-body aspiration in children

It is a frequent pediatric event and a common cause of morbidity and mortality in children, requiring accurate diagnosis and proper treatment. Diagnosis is usually based on clinical manifestations such as cough, dyspnea. stridor, respiratory distress and asymmetric decreased air entry or unilateral wheeze. Choking crisis may be absent or minimized. Chest X-ray may have no abnormalities or show signs such as asymmetrical hyperinflation, massive, fixed or changing atelectasis. Occasionally, hyperinflation or obstructive emphysema with atelectasis can be present in the same hemithorax. Inspiratory and expiratory chest X-rays show ipsilateral mediastinum movements. Most foreign bodies are not visible to chest X-ray exploration. Acute suffocation must be treated with Heimlich procedure. In later stages, diagnosis and treatment require rigid bronchoscopy. Prognosis is fairly positive with an early and complete foreign-body extraction.

La aspiración de un cuerpo extraño (CE) a la vía aérea en pediatría es un accidente frecuente, presenta importante morbimortalidad, por lo que requiere un diagnóstico y tratamiento oportuno. El diagnóstico usualmente se establece mediante hallazgos clínicos, siendo los más frecuentes tos, síndrome de penetración, y con menor frecuencia dificultad respiratoria, estridor, sibilancias unilaterales. La radiografía de tórax puede ser normal o alterada, mostrando hiperinsuflación unilateral, atelectasia u otros signos. La mayoría de los CE son radiotransparentes. Durante la fase aguda debe practicarse la maniobra de Heimlich, en cambio en la fase crónica el diagnóstico y tratamiento definitivo se hace mediante broncoscopía. La prevención es fundamental evitando que niños menores manipulen objetos pequeños, advertir el riesgo de asfixia por aspiración en los envases de alimentos riesgosos y de juguetes de pequeño tamaño. El pronóstico es bueno si la extracción del cuerpo extraño es precoz y completa.

Are white-rot fungi a real biotechnological option for the improvement of environmental health?

The use of white-rot fungi as a biotechnological tool for cleaning the environment of recalcitrant pollutants has been under evaluation for several years. However, it is still not possible to find sufficiently detailed investigations of this subject to conclude that these fungi can decontaminate the environment. In the present review, we have summarized and discussed evidence about the potential of white-rot fungi to degrade such pollutants as polycyclic aromatic hydrocarbons, dyes or antibiotics as an example of the complex structures that these microorganisms can attack. This review also discusses field experiment results and limitations of white-rot fungi trials from contaminated sites. Moreover, the use of catabolic potential of white-rot fungi in biopurification systems (biobeds) is also discussed. The current status and future perspectives of white-rot fungi, as a viable biotechnological alternative for improvement of environmental health are noted.

Atrazine dissipation and its impact on the microbial communities and community level physiological profiles in a microcosm simulating the biomixture of on-farm biopurification system.

The effects of repeated atrazine application (40 mg a.i.kg(-1)) on its degradation, microbial communities and enzyme activities were studied in a peat based biomixture composed by straw, soil and peat in the volumetric proportions of 2:1:1 that can be used in on-farm biopurification system. Atrazine removal efficiency was high (96%, 78% and 96%) after each atrazine application and did not show a lag phase. Microbial enzyme activities were reduced significantly with atrazine application but rapidly recovered. Microbial diversity obtained by BiologEcoplate was similar after the first and second atrazine application. However, an inhibitory effect was observed after the third application. After each atrazine application, culturable fungi were reduced, but rapidly recovered without significant changes in culturable bacteria and actinomycetes compared to the control. Denaturing gradient gel electrophoresis (DGGE) patterns demonstrated that microbial community structure remained relatively stable in time when compared to the controls. In conclusion, our results demonstrated that after successive ATZ applications, the peat based biomixture had a good degradation capacity. Moreover, microbiological assays demonstrated the robustness of the peat based biomixture from a microbiological point of view to support pesticide degradation.

Degradation of pesticide mixture on modified matrix of a biopurification system with alternatives lignocellulosic wastes.

The biobed systems were designed to retain and to degrade pesticides through the properties of a biomixture composed of straw (ST), topsoil and peat (PT) 2:1:1 v/v. The ST is the main substrate in the biomixture, as it allows the proliferation of fungi that promotes pesticide degradation. The use of readily available components in the biomixture is an important aspect to build a biobed. Therefore, potential use of readily available wastes as barley husk (BH), sawdust (SW) and oat husk (OH), as total or partial substitutes of ST were tested in pesticide degradation studies. Metabolite formation and the biological activities were also evaluated. Biomixture composed of OH was highly efficient in pesticide degradation, with t½ values of 28.6, 58.9 and 26.8 d for atrazine (ATZ), chlorpyrifos (CHL) and isoproturon (ISP). On the other hand, comparable for degrading capacities with the ST based biomixture were obtained with SW and BH, but only as partial replacement. Contrarily, high t½ values (more than 100 d) were obtained in biomixtures with total substitution of ST by SW or BH. Metabolite formation was observed in all biomixtures tested, but without clear formation patterns. Moreover, high and stable biological activity was observed in the biomixtures composed of OH. Therefore, our results demonstrated that ST can be partial or totally replaced by OH in the biomixture allowing an efficient degradation of pesticide mixture. However, it is recommended that ST can be only partially replaced by BH and SW in the biomixture to allow efficient pesticide degradation.