Arthrobotrys musiformis is a nematophagous fungus with potential for the biological control of Haemonchus contortus larvae. This study aimed to identify and demonstrate the proteolytic activity of extracellular products from A musiformis cultured in a liquid medium against H contortus infective larvae. A musiformis was cultured on a solid medium and further grown in a liquid medium, which was then processed through ion exchange and hydrophobic interaction chromatography. The proteolytic activity of the purified fraction was assayed with either gelatin or bovine serum albumin as substrate. Optimum proteolytic activity was observed at pH 8 and a temperature of 37°C. Results obtained with specific inhibitors suggest the enzyme belongs to the serine-dependent protease family. The purified fraction concentrate from A musiformis was tested against H contortus infective larvae. A time-dependent effect was observed with 77 per cent immobility after 48 hours incubation, with alteration of the sheath. It is concluded that A
musiformis is a potential candidate for biological control because of its resistant structures and also because of its excretion of extracellular products such as proteases. The present study contributes to the identification of one of the in vitro mechanisms of action of Amusiformis, namely the extracellular production of proteases against H contortus infective larvae. More investigations should be undertaken into how these products could be used to decrease the nematode population in sheep flocks under field conditions, thereby improving animal health while simultaneously diminishing the human and environmental impact of chemical-based drugs.
Non-adherent cells from PPD+ tuberculosis patients (TBP PPD+) and from healthy individuals treated with whole tuberculosis anergic immune sera or with its protein A-Sepharose IgG fraction, or with sera fraction separated by PPD-Sepharose chromatography, were submitted to immunofluorescence assays. Anti-human IgG or IgM FITC-conjugate were used to reveal the assays, and results were expressed by a fluorescence percentage or fluorescence index. The presence of IgG over the surface of PPD+ non-adherent cells was detected. High fluorescence percentages were observed only in those PPD+ cells treated with whole anergic serum or with its IgG fraction. Positive fluorescence index values were obtained only in those PPD+ cells treated with anergic serum, meanwhile fluorescence index was always negative when non-bound fractions from PPD-Sepharose were used. Results suggest that non-adherent population are the cell targets for the serum inhibitory factor, which previously has been detected to inhibit antigen response in PPD reactive cells and, point out the specific behavior of this factor, since it was eliminate by PPD-Sepharose chromatography. The IgG nature of the factor was demonstrated by SDS-PAGE and immunoelectrophoresis.
The effect of tuberculosis anergic immune sera adsorbed with BCG was studied on cocultures of adherent and non-adherent cells from PPD+ tuberculosis patient (TBP PPD+). This effect on the cocultures was quantified by lymphocyte transformation (LT) test using PPD as antigen. Only those cocultures with non-adherent cells from TBP PPD+ patients treated with anergic sera, inhibited the LT response induced by PPD, whereas sera adsorption with BCG eliminated the inhibitory effect.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.