• Journal of Microbiology and Biotechnology
• /
• v.18 no.5
• /
• pp.852-858
• /
• 2008

An extracellular protease (Mc1) was isolated from the nematode-trapping fungus Monacrosporium cystosporium by gel filtration, anion-exchange, and hydrophobic interaction chromatographies. This protease had a molecular mass of approximately 38 kDa and displayed an optimal activity at pH 7-9 and $56^{\circ}C$ (over 30 min). Its proteolytic activity was highly sensitive to the serine protease inhibitor PMSF (phenylmethylsulfonylfluoride, 0.1 mM), indicating that it belonged to the serine-type peptidase group. The Michaelis constant ($K_m$) and $V_max$ for substrate N-Suc-Ala-Ala-Pro-Phe-pNA were $1.67{\times}10^{-4}\;M$ and 0.6071 $OD_{410}$ per 30 s, respectively. This protease could degrade a broad range of substrates including casein, gelatin, BSA (bovine serum albumin), and nematode cuticle. Moreover, the enzyme could immobilize the free-living nematode Panagrellus redivivus and the pine wood nematode Bursaphelenchus xylophilus, suggesting that it might playa role in infection against nematodes. The encoding gene of Mc1 was composed of one intron and two exons, coding for a polypeptide of 405 amino acid residues. The deduced amino acid sequence of Mcl showed 61.4-91.9% identity to serine proteases from other nematode-trapping fungi. Our results identified that Mcl possessed biochemical properties including optimal reaction condition and substrate preference that are different from previously identified serine proteases.

• Journal of Korean Society of Forest Science
• /
• v.106 no.4
• /
• pp.509-517
• /
• 2017

This study was conducted to assess effect of thiacloprid fogging on non-target insect communities in Korean white pine forests. In addition, we assessed effect of thiacloprid fogging on mortality of Monochamus saltuarius as a vector of pine wood nematodes, and Apis mellifera as a non-target species. We compared abundance, species richness, and compostion of insects, and mortality of two insects among four treatment groups (control and thiacloprid-fogged groups with 3 different doses) located in the Kangwon National University Forest. For sampling of insects, 6 pitfall and 2 multi-funnel traps and 3 waterproof cloth sheets were placed in each study plot. In addition, M. saltuarius and A. mellifera were put into each meshed cage which installed at 7 m and 15 m heights in center of each study plot. Thiacloprid was fogged only once (middle May) in each plot using a fogging machine. Overall, thiacloprid fogging was appeared to be low toxicity to the abundance, species richness, and compostion of insects and mortality of A. mellifera, while it seems effectively impact on the mortality of M. saltuarius. However, thiacloprid fogging seems more influenced by microclimates in forests because the mortality of M. saltuarius in mesh cages was different according to heights and spatial locations. To control the population density and dispersal of M. saltuarius using by fogging techniques, therefore, it may be necessary to minimize the uncertainty about the effectiveness of thiacloprid fogging by improving the fogging techniques.

• Korean journal of applied entomology
• /
• v.62 no.1
• /
• pp.43-48
• /
• 2023

The efficacy of spinetoram sprayed from an unmanned helicopter to control two insect vectors of pine wood nematodes, Monochamus alternatus and M. saltuarius was assessed. By using a ULV (Ultra Low Volume) sprayer, the mortality rates of phenthoate, bifenthrin, etofenprox, and diflubenzuron, which are registered for use against coleopteran insects, indoxacarb and spinetoram, which are registered for use against lepidopteran insects, were evaluated for efficacy as aerial spraying agents. The ULV test, using 33- and 55-fold dilutions of phenthoate, bifenthrin, indoxacarb, and spinetoram demonstrated a 100% insect mortality rate upon contact and feeding mortality on the third day after treatment, while etofenprox and diflubenzuron exhibited a slightly lower mortality rate than the remaining compounds. Consequently, spinetoram was selected as a candidate pesticide for aerial spraying and its efficacy to control the insect vectors was assessed. The x 33 dilution of spinetoram resulted in a 98.6-100% control efficacy against two insect vectors. However, risk assessment for bees following aerial spraying will be necessary before applying the pesticide to control insect vectors.