The relatively little-investigated entomopathogen Conidiobolus coronatus secretes several proteinases into culture broth. Using a combination of ion-exchange and size-exclusion chromatography, we purified to homogeneity a serine proteinase of Mr 30,000-32,000, as ascertained by SDS-PAGE. The purified enzyme showed subtilisin-like activity. It very effectively hydrolyzed N-Suc-Ala(2)-Pro-Phe-pNa with a Km-1.36 x 10(-4) M and Kcat-24 s(-1), and N-Suc-Ala(2)-Pro-Leu-pNa with Km-6.65 x 10(-4) M and Kcat-11 s(-1). The specificity index k(cat)/K(m) for the tested substrates was calculated to be 176,340 s(-1) M(-1) and 17,030 s(-1) M(-1), respectively. Using oxidized insulin B chain as a substrate, the purified proteinase exhibited specificity to aromatic and hydrophobic amino-acid residues, such as Phe, Leu, and Gly at the P1 position, splitting primarily the peptide bonds: Phe(1)-Val(2), Leu(15)-Tyr(16), and Gly(23)-Phe(24). The proteinase appeared to be sensitive to the specific synthetic inhibitors of the serine proteinases DFP (diisopropyl flourophosphate) and PMSF (phenyl-methylsulfonyl fluoride) as well as to some naturally occurring protein inhibitors of chymotrypsin. It is worth noting that the enzyme exhibited the highest sensitivity to inhibition by AMCI-1 (with an association constant of 3 x 10(10) M(-1)), an inhibitor of cathepsin G/chymotrypsin from the larval hemolymph of Apis mellifera, reinforcing the possibility of involvement of inhibitors from hemolymph in insect innate immunity. The substrate specificity and proteinase inhibitor effects indicate that the purified proteinase from the fermentation broth of Conidiobolus coronatus is a subtilisin-like serine proteinase.
Download full-text PDF |
Source |
---|---|
http://dx.doi.org/10.1002/arch.20134 | DOI Listing |
Pathogens
January 2025
Laboratory of Analysis of Natural Compounds, Department of Environmental Analysis, Faculty of Chemistry, University of Gdańsk, Wita Stwosza 63, 80-308 Gdańsk, Poland.
Hemolymph enables communication between organs in insects and ensures necessary coordination and homeostasis. Its composition can provide important information about the physiological state of an insect and can have diagnostic significance, which might be particularly important in the case of harmful insects subjected to biological control. Linnaeus 1758 (Lepidoptera: Pyralidae) is a global pest to honey bee colonies.
View Article and Find Full Text PDFCytokine
January 2025
Museum and Institute of Zoology, Polish Academy of Sciences, Twarda 51/55, 00-818 Warszawa, Poland.
Cytokines are highly conserved between mammals and insects. The present study examines the multiple effects of interferon-gamma (IFN-γ) application on the immunological defence mechanisms of Galleria mellonella larvae, invertebrates which are gaining popularity as a replacement for mammalian research models in immunological studies. G.
View Article and Find Full Text PDFAm J Trop Med Hyg
January 2025
Department of Pathology, Atal Bihari Vajpayee Institute of Medical Sciences and Dr Ram Manohar Lohia Hospital, New Delhi, India.
There are no standard guidelines on the management of Conidiobolus infections, and many antifungals have been used, either alone or in combination. Relapses are common even after successful management. Although localized, they can result in severe facial disfigurement and may rarely cause disseminated entomophthoromycosis, which can have fatal complications.
View Article and Find Full Text PDFJ Invertebr Pathol
September 2024
Museum and Institute of Zoology, Polish Academy of Science, Twarda 51/55, 00-818 Warszawa, Poland; Biomibo, Strzygłowska 15, 04-872 Warsaw, Poland.
This work examines the insecticidal activity of octanoic acid (C8:0), a short-chain fatty acid detected in entomopathogenic fungus - Conidiobolus coronatus medium, against Lucilia sericata larvae and adults. The LD50 value was calculated as 3.04±0.
View Article and Find Full Text PDFFront Immunol
May 2024
Museum and Institute of Zoology, Polish Academy of Science, Warsaw, Poland.
Background: In response to the replace mammal research models with insects in preliminary immunological studies, interest has grown in invertebrate defense systems. The immunological response is regulated by cytokines; however, while their role in mammals is well understood, little is known of their function in insects. A suitable target for studies into insect immunology is (Lepidoptera), the wax moth: a common host for human fungal and bacterial pathogens.
View Article and Find Full Text PDFEnter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!