Effects of an Agaricus blazei aqueous extract pretreatment on paracetamol-induced brain and liver injury in rats.

The action of an Agaricus blazei aqueous extract pretreatment on paracetamol injury in rats was examined not only in terms of the classical indicators (e.g., levels of hepatic enzymes in the plasma) but also in terms of functional and metabolic parameters (e.g., gluconeogenesis). Considering solely the classical indicators for tissue damage, the results can be regarded as an indication that the A. blazei extract is able to provide a reasonable degree of protection against the paracetamol injury in both the hepatic and brain tissues. The A. blazei pretreatment largely prevented the increased levels of hepatic enzymes in the plasma (ASP, ALT, LDH, and ALP) and practically normalized the TBARS levels in both liver and brain tissues. With respect to the functional and metabolic parameters of the liver, however, the extract provided little or no protection. This includes morphological signs of inflammation and the especially important functional parameter gluconeogenesis, which was impaired by paracetamol. Considering these results and the long list of extracts and substances that are said to have hepatoprotective effects, it would be useful to incorporate evaluations of functional parameters into the experimental protocols of studies aiming to attribute or refute effective hepatoprotective actions to natural products.

Sporulation and diversity of arbuscular mycorrhizal fungi in Brazil Pine in the field and in the greenhouse.

The aim of this work was to assess the sporulation and diversity of arbuscular mycorrhizal fungi (AMF) at different forest sites with Araucaria angustifolia (Bert.) O. Ktze. (Brazil Pine). In addition, a greenhouse experiment was carried out to test the use of traditional trap plants (maize + peanut) or A. angustifolia to estimate the diversity of AMF at each site. Soil samples were taken in two State Parks at southwestern Brazil: Campos do Jordão (Parque Estadual de Campos do Jordão [PECJ]) and Apiaí (Parque Estadual Turístico do Alto Ribeira [PETAR]), São Paulo State, in sites of either native or replanted forest. In PECJ, an extra site of replanted forest that was impacted by accidental fire and is now in a state of recuperation was also sampled. The spore densities and their morphological identification were compiled at each site. In the greenhouse, soil samples from each site were used as inoculum to promote spore multiplication on maize + peanut or A. angustifolia grown on a sandy, low-fertility substrate. Plants were harvested, respectively, after 4 months or 1 year of growth and assessed for mycorrhizal root colonization. Spore counts and identification were also performed in the substrate, after the harvest of plants. Twenty-five taxa were identified considering all sites. Species richness and diversity were greater in native forest areas, being Acaulospora, the genus with the most species. Differences in number of spores, diversity, and richness were found at the different sites of each State Park. Differences were also found when maize + peanut or A. angustifolia were used as trap plants. The traditional methodology using trap plants seems to underestimate the diversity of the AMF. The use of A. angustifolia as trap plant showed similar species richness to the field in PECJ, but the identified species were not necessarily the same. Nevertheless, for PETAR, both A. angustifolia and maize + peanut underestimated the species richness. Because the AMF sporulation can be affected by many conditions, it is impossible to draw detailed conclusions from this kind of survey. More precise experiments have to be set up to isolate the different factors that modulate the ecophysiological interactions between host plant and endophyte.

Arbuscular mycorrhizal fungi associated with Araucaria angustifolia (Bert.) O. Ktze.

Specimens of Araucaria angustifolia from a native forest reserve and a reforested area in the State Park of Campos do Jordão were studied to determine the number and diversity of spore populations of arbuscular mycorrhizal fungi (AMF) and root colonization. Six randomly chosen plots (planted with 8- to 12-year-old plants) were delimited, four in the native forest and two in the reforested area. Rhizosphere and root samples were collected during two periods of the year corresponding to the rainy and dry seasons. A greenhouse experiment was set up for multiplication of field propagules (from the native forest and reforested area) for two consecutive generations. Araucaria leaves from the experimental plots were collected during the first sampling for nutrient analysis. Twenty-four AMF taxa were found and percent AM colonization was determined in all plots. Not all AMF species observed in the field were re-isolated through the recovery pot cultures, even after a second cultivation cycle. The foliar nutrient analysis showed higher nutrient levels in plants from the native forest than the reforested area. Generally, spore richness and diversity were highest during the warmer and more humid period and in the native forest plants.