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

Monotropastrum humile var. humile is associated with diverse ectomycorrhizal Russulaceae fungi in Japanese forests

The original publication is available at www.springerlink.comArticleECOLOGICAL RESEARCH. 23(6):983-993(2008)journal articl

The Effect of Jatropha Curcas Seed Meal on Growth Performance and Internal Organs Development and Lesions in Broiler Chickens

ABSTRACT The meal of Jatropha curcas (JCM) seed is a by-product of the biofuel industry and may potentially to be used as animal feed. However, its toxicity has prevented its utilization in animal nutrition mainly due to its high concentration of phorbol esters. This study was conducted to evaluate the effects of the dietary inclusion of JCM on the growth performance, feed digestibility and internal organs development of broilers. Thirty two 48-d-old Ross 308 broiler chickens housed in 16 pens (2 birds/pen) were used in this study. Birds were randomly allocated to dietary treatments comprising four JCM levels (negative control, 25, 50, or 100 g JCM/kg of diet) for four weeks. Results showed that increasing levels of JCM had a negative impact on broiler performance, reducing live weight, weight gain, and feed intake. Treatments led to a decrease of the relative weight of testis and spleen, and to an increase in heart relative weight. In broilers fed diets containing JCM, the testis were atrophic, presenting reduced size of the seminiferous tubule, which were small and lined within active sertoli cells and rare spermatogonia. This study illustrates the negative impact of diets containing JCM on broiler performance and JCM pathological effects on several organs