کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
4558164 | 1329925 | 2010 | 8 صفحه PDF | دانلود رایگان |
![عکس صفحه اول مقاله: Characterization of an extracellular lipase from the biocontrol fungus, Nomuraea rileyi MJ, and its toxicity toward Spodoptera litura Characterization of an extracellular lipase from the biocontrol fungus, Nomuraea rileyi MJ, and its toxicity toward Spodoptera litura](/preview/png/4558164.png)
An extracellular lipase from Nomuraea rileyi MJ was purified 23.9-fold with 1.69% yield by ammonium sulfate precipitation followed by Sephacryl S-100 HR column chromatography. By mass spectrometry and SDS–polyacrylamide gel electrophoresis, the molecular weight of the homogenous lipase was 81 kDa. The N-terminal sequence was determined as LeuSerValGluGlnThrLysLeuSerLysLeuAlaTyrAsnAsp and it showed no homology to sequences of known lipases. The optimum pH and temperature for activity were 8.0 and 35 °C, respectively. The enzyme was stable in the pH range 7.0–9.0 and at 15–35 °C for 1 h. Higher activity was observed in the presence of surfactants, Na+, NH4+ ions, NaN3 and ethylenediaminetetraacetic acid (EDTA), while Co2+ and Cu2+ ions, cysteine and dithiothreitol (DTT) strongly inhibited activity. The purified lipase hydrolyzed both synthetic and natural triglycerides with maximum activity for trilaurin and coconut oil, respectively. It also hydrolyzed esters of p-nitrophenol (pNP) with highest activity for p-nitrophenyl caprate (pNPCA). The purified lipase was found to promote N. rileyi spore germination in vitro in that germination reached 98% in conidial suspensions containing purified lipase at 2.75 U. Moreover, it enhanced toxicity of N. rileyi toward Spodoptera litura larvae with mortality via topical application reaching 63.3% at 4–10 days post-treatment which calculated to be 2.7 times higher than the mortality obtained using conidial suspensions alone.
Journal: Journal of Invertebrate Pathology - Volume 105, Issue 3, November 2010, Pages 228–235