Properties of fungal protease inhibitors from the integument and haemolymph of the silkworm and effect of an inhibitor on the fungal growth

Yoshida, Soh; Yamashita, M.; Yonehara, Satoshi; Eguchi, Masaharu

doi:10.1016/0305-0491(90)90021-k

Cited by 21 publications

(16 citation statements)

References 12 publications

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“…The inhibition of these digestive enzymes by inducible host factors could indirectly arrest the development of the pathogens and protect the host against tissue damage. The hemolymph of the silkworm Bombyx mori contains several inhibitors of fungal proteases, from which one, an inhibitor of subtilisin-like activity (a serine protease) referred to as fungal protease inhibitor F, was purified and characterized [9,23]. Similarly to the IMPI from G. mellonella described here, FPI-F is remarkably heat and acid stable.…”

Section: Discussionmentioning

confidence: 97%

Purification and characterization of an inducible metalloprotease inhibitor from the hemolymph of greater wax moth larvae, Galleria mellonella

Wedde

Weise

Kopáček

et al. 1998

European Journal of Biochemistry

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In this paper, we report the detection, purification and characterization of the first metalloprotease inhibitor (IMPI) from invertebrates. IMPI was purified from the hemolymph of last-instar larvae of Galleria mellonella by precipitation with trichloroacetic acid and heat followed by affinity chromatography on a thermolysin-Sepharose column and gel filtration or reverse-phase high-performance liquid chromatography. For the detection of inhibitor activity, a new azocoll assay was established. IMPI was only detectable in larvae that had been injected with bacterial or fungal provocators, suggesting that it is induced nonspecifically during the humoral immune response. Injection of larvae with IMPI rendered them resistant to thermolysin, in quantities that normally would be lethal for them. IMPI was shown to be specific for metalloproteases. The molecular mass of IMPI was determined by mass spectrometry to be 8360 Da. Purified IMPI was heterogeneous, owing to different degrees of glycosylation with hexose/hexosamine and deoxyhexose residues. Ten cysteine residues were found in the molecule, and these are presumed to form five disulfide bridges. The amino terminus was blocked, but a partial amino-acid sequence starting from the thermolysin cleavage site was determined; this sequence exhibited no similarity with other known proteins, suggesting that the IMPI represents a new type of protease inhibitor. Keywords : metalloproteases; metalloprotease inhibitor ; insect immunity ; Galleria mellonella.Insects are particularly resistant to micro-organisms. The endogenous defense of insects is based on cellular and humoral immune responses. The latter includes the synthesis of a broad spectrum of potent antimicrobial proteins that act directly against invading micro-organisms [1,2]. The response of insects to wounding or infection includes hemolymph coagulation and an activation of the prophenoloxidase cascade. The latter process is activated by serine proteases and regulated by serine-protease inhibitors in order to avoid excessive activation of and damage to host tissues [3,4]. In addition, protease inhibitors are thought to inhibit undesired proteolytic enzymes released by damaged cells or invading pathogens. Entomopathogenic fungi are the only group of micro-organisms that can infect insect hosts directly through their chitinous exoskeleton. Fungal extracellular proteases contribute to both integument penetration and digestion of host proteins. They are reported to determine the host specificity and the virulence of the producing fungal species [5,6]. Protease inhibitors detected in the cuticle or hemolymph of several insect species have been proposed to regulate not only endogenous proteases but also act against toxic fungal proteases hibitors and one cysteine protease inhibitor, but no metalloprotease inhibitor [12].Recently, it was reported that injection of zymosan or heatinactivated yeast cells resulted in reduced or delayed mortality of G. mellonella larvae after injection of living pathogenic fungal cells [13]. T...

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Section: Discussionmentioning

confidence: 97%

Purification and characterization of an inducible metalloprotease inhibitor from the hemolymph of greater wax moth larvae, Galleria mellonella

Wedde

Weise

Kopáček

et al. 1998

European Journal of Biochemistry

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“…Protease inhibitors that are prominent in body fluids are known to play important roles in host defenses by regulating immune reactions [6,7,9,17,19] and neutralizing pathogenic proteases [7,[22][23][24][25][26][27]. CvSI-2 originating from basophil cells of the digestive tubules and purified from cell-free hemolymph is likely distributed throughout the oyster tissues where it may play a role in host defenses against P. marinus and other pathogens.…”

Section: Discussionmentioning

confidence: 99%

“…They regulate protease activity involved in the coagulation of hemolymph, the activation of prophenoloxidase, and in the synthesis of cytokines and antimicrobial peptides [12][13][14][15][16][17][18][19][20][21]. Moreover, many protease inhibitors protect hosts by directly inactivating proteases of pathogens [22][23][24][25][26][27][28] as proteases are important virulence factors [29][30][31]. Most of what is known about protease inhibitor's role in invertebrate immunity however stems from studies of arthropods and there is limited information on protease inhibitors in marine molluscs including in commercially important bivalve species [32][33][34].…”

Section: Introductionmentioning

confidence: 99%

Evidence indicating the existence of a novel family of serine protease inhibitors that may be involved in marine invertebrate immunity

Xue

Itoh

Schey

et al. 2009

Fish & Shellfish Immunology

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“…Among the insect species investigated, a broad spectrum of inhibitors against proteolytic enzymes have been detected and identified (e.g., Polanowski et al, 1992;Kanost and Jiang, 1996). Protease inhibitors have been observed in tissue homogenates (Kucera, 1982), cuticle (Yoshida et al, 1990), and hemolymph (Boucias and Pendland, 1987). In addition to their function in metabolic processes, they may contribute to humoral defense reactions by inhibiting proteases released by invading pathogens.…”

Section: Role Of Protease Inhibitorsmentioning

confidence: 99%

Fungi as elicitors of insect immune responses

Gillespie

Bailey

Cobb³

et al. 2000

Arch. Insect Biochem. Physiol.

177

103

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Properties of fungal protease inhibitors from the integument and haemolymph of the silkworm and effect of an inhibitor on the fungal growth

Cited by 21 publications

References 12 publications

Purification and characterization of an inducible metalloprotease inhibitor from the hemolymph of greater wax moth larvae, Galleria mellonella

Purification and characterization of an inducible metalloprotease inhibitor from the hemolymph of greater wax moth larvae, Galleria mellonella

Evidence indicating the existence of a novel family of serine protease inhibitors that may be involved in marine invertebrate immunity

Fungi as elicitors of insect immune responses

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