Activity of the fungus Pleurotus ostreatus and of its proteases on Panagrellus sp. larvae

Biological control has been shown to be one of the possible biotechnological applications of fungi and their proteases. The objective of this study was to evaluate the nematicidal activity of the fungus Pleurotus ostreatus and its proteases on Panagrellus sp. larvae. Proteolytic activity of P. ostreatus (PLO 06) was measured and characterized at different pHs, temperatures and in the presence of a inhibitor (PMSF). Daily samples of culture medium were collected in order to determine the period of maximum enzyme production. A zymogram showed the profile of several proteases. Predatory activity of the fungus P. ostreatus (PLO 06) was evaluated on Panagrellus sp. larvae (assay A) as well as the nematicidal activity of PLO 06 proteases on the same larvae (assay B). At pH 9 and 60°C, the activity of the proteases reached the maximum. In the presence of inhibitor, there was no proteolytic activity. A sample collected on the fifth day of incubation showed the highest enzyme activity. P. ostreatus demonstrated capture activity on larvae Panagrellus sp. The values of the reduction of the larvae (Assay A) were: day 1 (65.6%); day 2 (77.4%); day 3 (95.2%). The reduction of the larvae (Assay B) was 42%. P. ostreatus (PLO 06) and its proteases were very effective against Panagrellus sp. larvae, demonstrating great potential for use in integrated biological control.Keywords: Pleurotus, protease, Panagrellus sp., biological control, nematicidal. Abbreviation: PMSF, Phenylmethylsulfonyl fluoride

Are ant assemblages of Brazilian veredas characterised by location or habitat type?

Wetland areas in the Brazilian Cerrado, known as “veredas”, represent ecosystems formed on sandy soils with high concentrations of peat, and are responsible for the recharge of aquiferous reservoirs. They are currently under threat by various human activities, most notably the clearing of vegetation for Eucalyptus plantations. Despite their ecological importance and high conservation value, little is known about the actual effects of human disturbance on the animal community. To assess how habitat within different veredas, and plantations surrounding them affect ant assemblages, we selected four independent vereda locations, two being impacted by Eucalyptus monoculture (one younger and one mature plantation) and two controls, where the wetland was surrounded by cerrado vegetation. Ant sampling was conducted in May 2010 (dry season) using three complementary methods, namely baits, pitfall traps, and hand collection, in the wetland and in the surrounding habitats. A total of 7,575 ants were sampled, belonging to seven subfamilies, 32 genera and 124 species.Ant species richness and abundance did not differ between vereda locations, but did between the habitats. When impacted by the monoculture, ant species richness and abundance decreased in wetlands, but were less affected in the cerrado habitat. Ant species composition differed between the three habitats and between vereda locations. Eucalyptus plantations had an ant species composition defined by high dominance of Pheidole sp. and Solenopsis invicta, while natural habitats were defined by Camponotus and Crematogaster species. Atta sexdens was strictly confined to native habitats of non-impacted “veredas”. Eucalyptus monocultures require high quantities of water in the early stages, which may have caused a decrease in groundwater level in the wetland, allowing hypogeic ants such as Labidus praedator to colonise this habitat

Infective endocarditis in intravenous drug abusers: an update

Infective endocarditis despite advances in diagnosis remains a common cause of hospitalization, with high morbidity and mortality rates. Through literature review it is possible to conclude that polymicrobial endocarditis occurs mainly in intravenous drug abusers with predominance in the right side of the heart, often with tricuspid valve involvement. This fact can be associated with the type of drug used by the patients; therefore, knowledge of the patient's history is critical for adjustment of the therapy. It is also important to emphasize that the most common combinations of organisms in polymicrobial infective endocarditis are: Staphylococcus aureus, Streptococcus pneumonia and Pseudomonas aeruginosa, as well as mixed cultures of Candida spp. and bacteria. A better understanding of the epidemiology and associated risk factors are required in order to develop an efficient therapy, although PE studies are difficult to perform due to the rarity of cases and lack of prospective cohorts.This work was supported by Portuguese Foundation for Science and Technology (FCT) through the grants SFRH/BPD/47693/2008, SFRH/BPD/20987/2004 and SFRH/BPD/72632/2010 attributed to Claudia Sousa, Claudia Botelho and Diana Rodrigues, respectively