Involvement of cysteine proteinases in excystment of Paragonimus ohirai metacercariae induced by sodium cholate and A23187

2003 ◽  
Vol 77 (1) ◽  
pp. 21-26 ◽  
Author(s):  
T. Ikeda

AbstractThe involvement of intrinsic proteinases in the excystment of Paragonimus ohirai metacercariae was studied in in vitro excystment induced by sodium (Na) cholate, a bile salt and A23187, a Ca2+ ionophore. The effects of various proteinase inhibitors on the in vitro excystment were examined and similar inhibitory profiles were obtained. Benzyloxycarbonyl-L-leucyl-L-leucinal (Z-Leu-Leu-H), a cysteine proteinase inhibitor and 4-(2-aminoethyl)-benzenesulfonyl fluoride (Pefabloc SC), a serine proteinase inhibitor completely inhibited excystment, while L-3-carboxy-2,3-trans-epoxypropionyl-leucylamido (4-guanidino)-butane (E-64), a cysteine proteinase inhibitor and leupeptin, a cysteine/serine proteinase inhibitor permitted partial excystment at a lower rate, but inhibited it from proceeding from the partial excystment stage. In secretions released from metacercariae during excystment, proteinase activities detected towards various fluorogenic peptidyl substrates were almost completely inhibited by Z-Leu-Leu-H and E-64, but not by Pefabloc SC. Sodium cholate induced a higher secretion of cysteine proteinases and a higher rate of excystment than A23187. Profiles of cysteine proteinase activities towards five peptidyl substrates detected were markedly different among the two secretions and the lysate of newly excysted juveniles. Newly excysted juveniles released cysteine proteinases with similar activity profiles and levels to metacercariae induced by Na cholate-incubation, whereas the release of cysteine proteinases was reduced compared with metacercariae induced by A23187-incubation. These results provide valuable information about the involvement of intrinsic proteinases in metacercarial excystment.

2002 ◽  
Vol 383 (5) ◽  
pp. 839-842 ◽  
Author(s):  
Natasa Sever ◽  
Metka Filipic ◽  
Joze Brzin ◽  
Tamara T. Lah

Abstract Various types of proteinases are implicated in the malignant progression of human and animal tumors. Proteinase inhibitors may therefore be useful as therapeutic agents in antiinvasive and antimetastatic treatment. The aims of this study were (1) to estimate the relative importance of proteinases in B16 cell invasion in vitro using synthetic, classspecific proteinase inhibitors and (2) to assess the inhibitory effect of some naturally occurring cysteine proteinase inhibitors. Serine proteinase inhibitor reduced invasiveness by up to 24%, whereas inhibition of aspartic proteinases reduced invasion by 11%. Synthetic inhibitors of cysteine proteinases markedly impaired invasion: cathepsin B inhibitors, particularly Ca 074Me, inhibited invasion from 20 40%, whereas cathepsin L inhibitor Clik 148 reduced invasion by 11%. The potato cysteine proteinase inhibitor PCPI 8.7 inhibited invasion by 21%, whereas another potato inhibitor, PCPI 6.6, and the mushroom cysteine proteinase inhibitor clitocypin had no effects. As the inhibitors that inhibited cathepsin B were in general more efficient at impairing the invasiveness, we conclude that of the two cysteine proteinases, cathepsin B plays a more important role than cathepsin L in murine melanoma cell invasion.


2000 ◽  
Vol 35 (1) ◽  
pp. 70-76 ◽  
Author(s):  
T. C. Elden

The influence of leupeptin, a cysteine and serine proteinase inhibitor, on alfalfa weevil, Hypera postica (Gyllenhal), growth and development was investigated over nine successive generations. Concern that ingestion of proteinase inhibitors by phytophagous insects could induce production of inhibitor-insensitive proteinase activity initiated this investigation. The percent alfalfa weevil larval, pupal and adult survival, and defoliation was significantly lower on alfalfa foliage treated with leupeptin than on untreated foliage in all nine generations tested. Main effects for generations and treatment times generation were nonsignificant for all variables. This study demonstrates that after nine generations leupeptin, when compared to an untreated control, does not lose its ability to significantly inhibit alfalfa weevil growth and development. This suggests that the alfalfa weevil did not utilize or induce other proteinases (digestive enzymes) to compensate for inhibition of one of its major proteinases.


2006 ◽  
Vol 96 (2) ◽  
pp. 167-172 ◽  
Author(s):  
B. Oppert ◽  
P. Walters ◽  
M. Zuercher

AbstractDigestion in the larger black flour beetle, Cynaeus angustus (LeConte), was studied to identify new control methods for this pest of stored grains and grain products. The physiological pH of the larval gut, as measured with extracts in water, was approximately 6.1, and the pH for optimal hydrolysis of casein by gut extracts was 6.2 when buffers were reducing. However, under non-reducing conditions, hydrolysis of casein and synthetic serine proteinase substrates was optimal in alkaline buffer. Three major proteinase activities were observed in zymograms using casein or gelatin. Caseinolytic activity of C. angustus gut extracts was inhibited by inhibitors that target aspartic and serine proteinase classes, with minor inhibition by a cysteine proteinase inhibitor. In particular, soybean trypsin and trypsin/chymotrypsin inhibitors were most effective in reducing the in vitro caseinolytic activity of gut extracts. Based on these data, further studies are suggested on the effects of dietary soybean inhibitors of serine proteinases, singly and in combination with aspartic and cysteine proteinase inhibitors, on C. angustus larvae. Results from these studies can be used to develop new control strategies to prevent damage to grains and stored products by C. angustus and similar coleopteran pests.


1984 ◽  
Vol 220 (1) ◽  
pp. 147-155 ◽  
Author(s):  
M Pagano ◽  
F Esnard ◽  
R Engler ◽  
F Gauthier

The inhibition of human liver cathepsin L by two specific proteinase inhibitors present in human serum, namely alpha 2 cysteine-proteinase inhibitor and the low-Mr cysteine-proteinase inhibitor, was studied. Kinetic parameters, including inhibition constants (Ki) and rate constants for association and dissociation (k+1 and K-1), were determined. The values found are consistent with a possible physiological function of these inhibitors to control cathepsin L activity. Furthermore, a transfer of active proteinase from the complex with either cysteine-proteinase inhibitor species to alpha 2-macroglobulin was demonstrated in vitro. Given the rate of dissociation of both cathepsin-L-cysteine-proteinase inhibitor complexes, a function of transitory inhibitor can therefore be hypothesized for these proteins and might then provide an explanation of the clearance of lysosomal proteinases.


2012 ◽  
Vol 24 (1) ◽  
pp. 211
Author(s):  
A. M. Lichtenauer ◽  
L. D. Spate ◽  
R. S. Prather ◽  
J. A. Green

Biochemical differences exist between oocytes that give rise to viable blastocysts and oocytes that give rise to embryos that are developmentally compromised. For example, specific proteolytic enzymes (e.g. cathepsin B) are transcriptionally abundant in in vitro-matured bovine oocytes from prepubertal heifers that have diminished developmental potential. The effects of the cysteine proteinase inhibitor, E-64, was recently investigated in bovine cumulus–oocyte complexes (COC) that represented both poor- and good-quality oocytes. Those reports revealed that the addition of E-64 promoted both oocyte maturation and subsequent embryo development. This project sought to determine if similar results would be obtained in a porcine oocyte/embryo culture system. Inclusion of 10 and 20 μM E-64 in maturation medium was performed. Maturation rates of porcine COC in 20 μM E-64 were elevated compared to those incubated in 10 μM E-64 (74% vs 53%; P < 0.05) or without E-64 (55%; P < 0.05: N = 1750 oocytes tested). Successful maturation to metaphase II was based on the presence of a polar body and a uniform cytoplasm 44 h after follicular aspiration. Based on these preliminary results and the earlier bovine work, it was hypothesized that the E-64 was having little influence on normal oocytes, but was promoting maturation of low-quality oocytes, possibly those that were beginning to degenerate. Consequently, 20 μM of E-64 was added to the maturation media of COC segregated based on morphological characteristics of the oocytes. Good COC had a homogeneous cytoplasm and greater than 3 layers of cumulus cells; the COC were considered poor if they displayed a nonhomogeneous cytoplasm and 1 layer or less of cumulus cells, yet were still considered fertilizable. Without E-64, an increase in maturation was measured when good oocytes were compared to poor oocytes (52% vs 29%; P < 0.05: N = 1600). No significant differences in maturation were observed between good oocytes incubated in the presence or absence of E-64. Likewise, no significant differences were observed between poor oocytes incubated in the presence or absence of E-64. The percentage of maturation of good oocytes cultured in E-64 was significantly higher than that of poor oocytes cultured with E-64 (67% vs 43%; P < 0.05). Maturation with the inhibitor did not significantly affect the subsequent cleavage or blastocyst rates of embryos that arose from these oocyte groups after fertilization. These experiments suggest that inhibition of cysteine proteinases significantly promotes oocyte maturation, as was seen in previous bovine work. Our data did not support the hypothesis that cysteine proteinase inhibition was selectively improving maturation of poor oocytes within the pool. It remains possible that increased maturation in good oocytes is a result of cysteine inhibition on juvenile oocytes that morphologically appeared good and the effect was less on already degenerated oocytes that appeared poor. Differences between treatments were determined by ANOVA with post-test by Tukey's multiple comparison test.


2001 ◽  
Vol 14 (4) ◽  
pp. 318-324 ◽  
Author(s):  
Torsten Hansen ◽  
Peter K Petrow ◽  
Andreas Gaumann ◽  
Gernot M Keyszer ◽  
Mike Otto ◽  
...  

Parasitology ◽  
2004 ◽  
Vol 130 (2) ◽  
pp. 203-211 ◽  
Author(s):  
G. STEPEK ◽  
D. J. BUTTLE ◽  
I. R. DUCE ◽  
A. LOWE ◽  
J. M. BEHNKE

We examined the mechanism of action and compared the anthelmintic efficacy of cysteine proteinases from papaya, pineapple, fig, kiwi fruit and Egyptian milkweed in vitro using the rodent gastrointestinal nematode Heligmosomoides polygyrus. Within a 2 h incubation period, all the cysteine proteinases, with the exception of the kiwi fruit extract, caused marked damage to the cuticle of H. polygyrus adult male and female worms, reflected in the loss of surface cuticular layers. Efficacy was comparable for both sexes of worms, was dependent on the presence of cysteine and was completely inhibited by the cysteine proteinase inhibitor, E-64. LD50 values indicated that the purified proteinases were more efficacious than the proteinases in the crude latex, with purified ficin, papain, chymopapain, Egyptian milkweed latex extract and pineapple fruit extract, containing fruit bromelain, having the most potent effect. The mechanism of action of these plant enzymes (i.e. an attack on the protective cuticle of the worm) suggests that resistance would be slow to develop in the field. The efficacy and mode of action make plant cysteine proteinases potential candidates for a novel class of anthelmintics urgently required for the treatment of humans and domestic livestock.


1989 ◽  
Vol 258 (1) ◽  
pp. 187-192 ◽  
Author(s):  
R Brandsch ◽  
V Bichler ◽  
B Krauss

Expression of the 6-hydroxy-D-nicotine oxidase (6-HDNO) gene from Arthrobacter oxidans cloned into Escherichia coli showed a marked temperature-dependence. Transformed E. coli cells grown at 30 degrees C exhibited a several-fold higher 6-HDNO activity than did cells grown at 37 degrees C. This effect did not depend on the promoter used for expression of the cloned gene in E. coli, nor was it an effect of 6-HDNO mRNA instability at 37 degrees C. Studies performed in vivo and in vitro revealed that an increased susceptibility of apo-6-HDNO to proteolytic attack at 37 degrees C was responsible for the observed phenomenon. Extracts from cells grown at 37 degrees C showed on Western blots a decrease in immunologically detectable 6-HDNO polypeptide when compared with extracts from cells grown at 30 degrees C. The 6-HDNO polypeptide is covalently modified by attachment of the cofactor FAD to a histidine residue. It could be shown that covalent flavinylation of the apoenzyme in vitro, i.e. formation of holoenzyme, by incubation of cell extracts with FAD and phosphoenolpyruvate protected the 6-HDNO polypeptide from degradation at 37 degrees C. Of a variety of proteinase inhibitors tested only the cysteine-proteinase inhibitor L-3-trans-carboxyoxiran-2-carbonyl-L-leucylagmatine (E64) prevented degradation, by up to 70%, of the apoenzyme.


1985 ◽  
Vol 13 (6) ◽  
pp. 1018-1021 ◽  
Author(s):  
J. W. C. BIRD ◽  
L. WOOD ◽  
I. SOHAR ◽  
E. FEKETE ◽  
R. COLELLA ◽  
...  

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