Marliane de Cássia Soares da Silva

Enrichment of mushrooms: An interesting strategy for the acquisition of lithium

The capability of Pleurotus ostreatus mushroom to accumulate lithium (Li) and the accessibility of this Li compared with lithium carbonate (Li(2)CO(3)), often used as psychiatric medicine, were investigated. Mushrooms were produced on a substrate-based on coffee husk, with different added concentrations of lithium chloride (LiCl). Biological efficiency (BE), the crude protein content, the concentration of Li and other elements present in mushrooms were determined. The sequential extraction and in vitro test were used to verify the accessibility and the degree of solubility of this element. Li concentration in mushrooms was directly influenced by increasing LiCl concentration in the substrate (P<0.05). The BE was not affected by different concentrations of LiCl. Li present in enriched mushrooms showed greater accessibility than in Li(2)CO(3). Therefore, P. ostreatus mushrooms, enriched with lithium can be an alternative source of Li, as well as being a food with high nutritional value.

In vivo bioavailability of selenium in enriched Pleurotus ostreatus mushrooms

The in vivo bioavailability of Se was investigated in enriched Pleurotus ostreatus mushrooms. A bioavailability study was performed using 64 Wistar male rats separated in 8 groups and fed with different diets: without Se, with mushrooms without Se, with enriched mushrooms containing 0.15, 0.30 or 0.45 mg kg(-1) Se and a normal diet containing 0.15 mg kg(-1) of Se using sodium selenate. The experiment was performed in two periods: depletion (14 days) and repletion (21 days), according to the Association of Official Analytical Chemists. After five weeks, the rats were sacrificed under carbon dioxide, and blood was drawn by heart puncture. Blood plasma was separated by centrifugation. The total Se concentration in the plasma of rats fed with enriched mushrooms was higher than in rats fed with a normal diet containing sodium selenate. The plasma protein profiles were obtained using size exclusion chromatography (SEC) and UV detectors. Aliquots of effluents (0.5 mL per minute) were collected throughout in the end of the chromatographic column. However, Se was determined by graphite furnace atomic absorption spectrometry (GF AAS) only in the aliquots where proteins were detected by SEC-UV. The plasma protein profile of rats fed with different diets was similar. The highest Se concentration was observed in a peptide presenting 8 kDa. Furthermore, the higher Se concentration in this peptide was obtained for rats fed with a diet using enriched mushrooms (7 μg L(-1) Se) compared to other diets (2-5 μg L(-1) Se). These results showed that Se-enriched mushrooms can be considered as an alternative Se food source for humans, due to their high bioavailability.

Degradation of Oxo-Biodegradable Plastic by Pleurotus ostreatus

Growing concerns regarding the impact of the accumulation of plastic waste over several decades on the environmental have led to the development of biodegradable plastic. These plastics can be degraded by microorganisms and absorbed by the environment and are therefore gaining public support as a possible alternative to petroleum-derived plastics. Among the developed biodegradable plastics, oxo-biodegradable polymers have been used to produce plastic bags. Exposure of this waste plastic to ultraviolet light (UV) or heat can lead to breakage of the polymer chains in the plastic, and the resulting compounds are easily degraded by microorganisms. However, few studies have characterized the microbial degradation of oxo-biodegradable plastics. In this study, we tested the capability of Pleurotus ostreatus to degrade oxo-biodegradable (D2W) plastic without prior physical treatment, such as exposure to UV or thermal heating. After 45 d of incubation in substrate-containing plastic bags, the oxo-biodegradable plastic, which is commonly used in supermarkets, developed cracks and small holes in the plastic surface as a result of the formation of hydroxyl groups and carbon-oxygen bonds. These alterations may be due to laccase activity. Furthermore, we observed the degradation of the dye found in these bags as well as mushroom formation. Thus, P. ostreatus degrades oxo-biodegradable plastics and produces mushrooms using this plastic as substrate.

Colonização micorrízica em plantios de eucalipto

A associacao micorrizica e advinda da associacao simbiotica entre alguns fungos do solos e da maioria das raizes das plantas. O eucalipto possui a capacidade de se associar com dois tipos de micorrizas, a micorriza arbuscular e a ectomicorriza, o que depende muito da sua idade. Este trabalho objetivou avaliar a taxa de colonizacao por fungos micorrizicos arbusculares (MA) e ectomicorrizicos (ECM) e o numero de esporos de fungos micorrizicos arbusculares em plantios comerciais de Eucalyptus grandis e Eucalyptus urophylla, com diferentes idades e manejos, no periodo de dezembro de 2002 a fevereiro de 2004, na regiao leste de Minas Gerais, Brasil. Em todas as coletas e em todas as idades dos plantios, foram encontradas MA, e ECM e a media geral da colonizacao por fungos micorrizicos arbusculares (FMA) foi de 26%. O numero medio de esporos desses fungos de 374,7 por 100 g de solo e a colonizacao por fungos ectomicorrizicos (FECM) de 20,2%. As maiores porcentagens de colonizacao por FECM foram observadas em areas de plantios mais jovens, mas a sua maior diversidade foi observada nas areas de plantios mais velhos. Conclui-se que a epoca de coleta, a idade do plantio e o manejo do solo afetam a colonizacao micorrizica e tambem a diversidade de fungos ECM e que a sucessao de eucalipto com FMA-FECM nao e regra e e muito influenciada pelo tipo de manejo.

Nitrogen-fixing bacteria in Eucalyptus globulus plantations.

Eucalypt cultivation is an important economic activity worldwide. In Portugal, Eucalyptus globulus plantations account for one-third of the total forested area. The nutritional requirements of this crop have been well studied, and nitrogen (N) is one of the most important elements required for vegetal growth. N dynamics in soils are influenced by microorganisms, such as diazotrophic bacteria (DB) that are responsible for biological nitrogen fixation (BNF), so the aim of this study was to evaluate and identity the main groups of DB in E. globulus plantations. Samples of soil and root systems were collected in winter and summer from three different Portuguese regions (Penafiel, Gavião and Odemira). We observed that DB communities were affected by season, N fertilization and moisture. Furthermore Bradyrhizobium and Burkholderia were the most prevalent genera in these three regions. This is the first study describing the dynamic of these bacteria in E. globulus plantations, and these data will likely contribute to a better understanding of the nutritional requirements of eucalypt cultivation and associated organic matter turnover.

Production of Selenium-Enriched Mushrooms in Coffee Husks and Use of This Colonized Residue

The sustainability of the coffee production chain involves the recovery of its byproducts. The coffee husk represents approximately 40% of the fruit. A small portion of this byproduct is used as organic fertilizer, while most of the coffee husk is discarded in the environment or incinerated. The use of waste such as the coffee husk for food production is limited due to the presence of antinutritional components (tannins and caffeine) and high-fiber content. The production of edible mushrooms using coffee husks is an option for recovering this byproduct because of the fungis ability to degrade these compounds and convert the lignocellulosic residues to food with high commercial and nutritional value. Moreover, with the use of these fungi, this byproduct can also be used to enrich mushrooms with selenium or other minerals important for human health and to produce lignocellulolytic enzymes or animal feed.

Effect of inoculation of symbiotic fungi on the growth and antioxidant enzymes’ activities in the presence of Fusarium subglutinans f. sp. ananas in pineapple plantlets

The inoculation with symbiotic fungi, Arbuscular mycorrhizal fungi (AMF) and/or Piriformospora indica on the growth, nutrient absorption, and induction of antioxidant enzyme activities in plantlets of pineapple ‘Imperial’ (fusariosis-resistant) and ‘Pérola’ (fusariosis-susceptible) in the presence of Fusarium subglutinans f. sp. ananas was investigated. The experiment was comprised by two cultivars, with or without fungal inoculation (Claroideoglomus etunicatum, Rhizophagus clarus, and P. indica, a mixture of all the fungi, and the control—absence of fungal inoculation), with or without applying Fusarium conidia, and with four replicates. In both cultivars, nutrient absorption was higher in the AMF plantlets compared to those inoculated with P. indica or the control ones, although it was more efficient in ‘Imperial’ than in ‘Pérola’. Inoculation with AMF and/or P. indica as well as the pathogen influenced differently the activities of superoxide dismutase, catalase, glutathione reductase, peroxidase, and polyphenol oxidase, in the shoots or roots of pineapple plantlets in both cultivars. Inoculated plantlets with mixture of all the fungi also exhibited a better growth and nutrient absorption, and generally, the ‘Imperial’ responded better than ‘Pérola’. In addition, these plantlets developed better than the control even in the presence of pathogen, indicating that inoculation with AMF and/or P. indica may contribute to the production of more resistant propagative material. Increased antioxidant enzyme activity is a potential strategy for managing this plant for explore biological control as an alternative to reduce environmental and health impacts by reducing the use of fungicides.