Metaprofiling of the Bacterial Community in Colonized Compost Extracts by <i>Agaricus subrufescens</i>

It is well-known that bacteria and fungi play important roles in the relationships between mycelium growth and the formation of fruiting bodies. The sun mushroom, Agaricus subrufescens, was discovered in Brazil ca. 1960 and it has become known worldwide due to its medicinal and nutritional properties. This work evaluated the bacterial community present in mushroom-colonized compost extract (MCCE) prepared from cultivation of A. subrufescens, its dynamics with two different soaking times and the influence of the application of those extracts on the casing layer of a new compost block for A. subrufescens cultivation. MCCEs were prepared through initial submersion of the colonized compost for 1 h or 24 h in water followed by application on casing under semi-controlled conditions. Full-length 16S rRNA genes of 1 h and 24 h soaked MCCE were amplified and sequenced using nanopore technology. Proteobacteria, followed by Firmicutes and Planctomycetes, were found to be the most abundant phyla in both the 1 h and 24 h soaked MCCE. A total of 275 different bacterial species were classified from 1 h soaked MCCE samples and 166 species from 24 h soaked MCCE, indicating a decrease in the bacterial diversity with longer soaking time during the preparation of MCCE. The application of 24 h soaked MCCE provided increases of 25% in biological efficiency, 16% in precociousness, 53% in the number of mushrooms and 40% in mushroom weight compared to control. Further investigation is required to determine strategies to enhance the yield and quality of the agronomic traits in commercial mushroom cultivation

Chronic toxicity test with sea urchin Echinometra lucunter and Lytechinus variegatus (Echinodermata: Echinoidea), exposed to light-stick - flag paternoster used for longline surface fishing

In this work, the chronic toxicity of a mixture of light-stick chemicals and water was tested. The light-stick is used in fishery activities to catch swordfish. The tubes were collected on the beaches of the Costa dos Coqueiros - BA, Brazil, in the period from 14th to 31st July 2007. The method used was a short chronic toxicity test where embryos of the sea urchins Echinometra lucunter and Lytechinus variegatus were exposed to a stock solution consisting of the supernatant formed from a mixture of sea water and the orange-colored light-stick chemical. After a preliminary test, concentrations defined were 0.002, 0.003, 0.01, 0.02, 0.1, 1.0% of stock solution. The final test ran for 36 hours for E. Lucunter and 24 hours for L. variegatus with 4 replicates for each concentration. The value of EC50 - 36h was 0.062% with confidence limits ranging from 0.042 to 0.079% and the EC50 - 24h was 0.011% with confidence limits ranging from 0.009 to 0.014%, i.e., the chemical mix present in the light-stick is potentially toxic. So, as these flags are commonly used for fishing there is potential danger in their disposal in the open ocean.<br>O objetivo deste trabalho foi avaliar a toxicidade crônica da água do mar em contato com o líquido contido no light-stick, sinalizador utilizado em pesca de espinhel de superfície para a captura de espadarte. Os tubos foram coletados nas praias da Costa dos Coqueiros - BA, no período de 14 a 31 de Julho de 2007. O método utilizado para a verificação da toxicidade crônica foi o teste de curta duração com embriões de ouriço-do-mar Echinometra lucunter e Lytechinus variegatus, os ensaios foram realizados com solução estoque que consiste do sobrenadante formado a partir de uma mistura de água do mar com o líquido do sinalizador de coloração laranja. Após um teste preliminar as concentrações definidas foram 0.002; 0.003; 0.01; 0.02; 0.1; 1.0%. O teste definitivo teve duração de 36 horas para E. lucunter e 24 horas para L. variegatus, sendo preparadas 4 réplicas para cada concentração. O valor da CE50 - 36h encontrado foi de 0.062% com limites de aceitabilidade variando de 0.042 a 0.079% e a CE50 - 24h encontrada foi de 0.011% com limites de aceitabilidade variando de 0.009 a 0.014%, ou seja, os compostos químicos presentes no light-stick são potencialmente tóxicos. Portanto já que esses sinalizadores são utilizados comumente como petrechos de pesca há a necessidade de que eles sejam recolhidos, pois podem causar efeitos adversos quando abrem nos oceanos