The heat-stable enterotoxin (ST) produced by enterotoxigenic Escherichia coli is an extracellular peptide toxin that evokes watery diarrhea in the host. Two types of STs, STI and STII, have been found. Both STs are synthesized as precursor proteins then converted to active forms with intramolecular disulfide bonds after being released into periplasm. finally translocated across outer membrane through a tunnel made TolC. However, it unclear how formed periplasm led TolC channel. Several...

Aeromonas spp. are Gram-negative rod-shaped bacteria ubiquitously distributed in diverse water sources. Several known as human and fish pathogens. Recently, attention has been focused on the relationship between bacterial biofilm formation pathogenicity or drug resistance. However, there have few reports by . This study is first to examine vitro components of several clinical environmental strains. A assay using 1% crystal violet a polystyrene plate revealed that most strains used this...

We compared the effects of dimeric marine toxins, bistheonellide A, and swinholide on actin polymerization. Bistheonellide A possess two identical side chains with similar structures to those other mycalolide B, aplyronine A. By monitoring changes in fluorescent intensity pyrenyl-actin, was found inhibit polymerization G-actin depolymerize F-actin a concentration-dependent manner. The relationship between concentration its inhibitory activity suggested that one molecule binds molecules...

We examined the properties of exotoxins produced by Aeromonas trota (A. enteropelogenes), one diarrheagenic species Aeromonadaceae. Nine 19 A. isolates that grew on solid media containing erythrocytes showed hemolytic activity. However, activities culture supernatants these strains were markedly lower than those sobria when cultured in liquid medium, and amount hemolysin detected immunoblotting using antiserum against was also low. A mouse intestine loop assay living bacterial cells 701...

Abstract Aeromonas sobria causes septic shock, a condition associated with high mortality. To study the mechanism of shock by A. infection, we examined vascular leakage (VL) activity serine proteinase (ASP), secreted this pathogen. Proteolytically active ASP induced VL mainly in bradykinin (BK) B2 receptor-, and partially histamine-H1 receptor-dependent manner guinea pig skin. The peaked at 10 min to 1.8-fold initial an increased BK receptor dependency, attenuated almost completely within 30...

Abstract Aeromonas sobria causes pus and edema at sites of infection. However, the mechanisms underlying these effects have not been elucidated. C5a, amino-terminal fragment complement 5th component (C5), mimics events. To investigate involvement C5a in pathophysiology A. infection, we examined release from human C5 by a serine protease (ASP), putative virulence factor secreted this bacterium. incubated with enzymatically active ASP induced neutrophil migration dose-dependent manner an...

Dopamine (DA) induction of the long-term enhancement (LTE) slow muscarinic depolarizing response to methacholine (MCh), equivalent EPSP (S-EPSP), was previously found be mimicked by exogenous cyclic AMP (cAMP) in rabbit superior cervical ganglion (SCG). DA-induced LTE S-EPSP shown depressed some DA antagonists. We now show that (15 microM), its analog, 2-amino-6,7-dihydroxy-1,2,3,4-tetrahydronaphthalene (ADTN), and a D2 receptor antagonist, metoclopramide, each can induce both MCh...

The effect of a serine protease (ASP) secreted from Aeromonas sobria on plasma coagulation was investigated. Proteolytically active ASP promoted human in dose‐dependent manner. Consistent with the preference for factor Xa‐specific oligo‐peptide substrate, produced enzymatic activity prothrombin but not factors IX and X. cleaved to produce enzymatically 37 kDa‐fragment displaying same molecular mass as α‐thrombin. is first bacterial that produces α‐thrombin, through which may contribute...

Aeromonas sobria infection often advances to sepsis, in which interaction of bacterial components with plasma proteins possibly causes various disorders. This bacterium releases a serine protease (ASP), putative virulence factor, and binds fibrinogen. To study the ASP effect on fibrinogen, we incubated fibrinogen or investigated their clotting elicited by thrombin, converts fibrin clot. Enzymatically active retarded dose-dependent manner starting at an concentration 10 nM. also 3 nM above,...

Abstract Human histo-blood group A transferase (AT) catalyzes the biosynthesis of oligosaccharide antigen important in blood transfusion and cell/tissue/organ transplantation. This enzyme may synthesize Forssman (FORS1) FORS system when exon 3 or 4 AT mRNA is deleted and/or LeuGlyGly tripeptide at codons 266–268 replaced by GlyGlyAla. The Met69Ser/Thr substitutions also confer weak glycolipid synthase (FS) activity. In this study, we prepared human derivative constructs containing any 20...

We examined the effects of C-type natriuretic peptide (CNP) on cyclic GMP production and catecholamine synthesis in cultured bovine adrenal medullary cells. 1) CNP increased intracellular content a concentration-dependent manner (10-1000 nM). 2) The induced by 1 microM reached 200-fold increase, effect was most potent among family. 3) CNP-induced attenuated endothelin (1 microM) angiotensin II (0.1-1 microM). 4) When cells were with hypertonic NaCl medium, potentiated time (1-4 days)-...

Aeromonas sobria is a pathogen causing food-borne illness. In immunocompromised patients and the elderly, A. can leave intestinal tract, this opportunistically leads to severe extraintestinal diseases including sepsis, peritonitis, meningitis. To cause such diseases, must pass through epithelial barrier. The mechanism of bacterial translocation has not been established. Herein we used (T84) cultured cells investigate effect serine protease (ASP) on junctional complexes that maintain...

The effects of Ptychodiscus brevis toxin (PbTx-3) on 22Na influx, 45Ca influx and catecholamine secretion were examined in cultured bovine adrenal medullary cells compared with the classical neurotoxins. PbTx-3 alone had no effects, but greatly enhanced veratridine (30 microM)-induced Na Ca secretion, a EC50 30, 25 23 nM, respectively. (1 microM) reduced values approximately 3-fold increased maximal responses caused by saturating concentration (300 1.3 fold. alpha- beta-Scorpion venom...

We examined the ability of Aeromonas hydrophila to lyse elastin. Eight 13 strains showed elastolytic activity on agar medium containing elastin and 5 did not. In order examine involvement metalloprotease A. (AMP) in activity, we made amp-deletion mutant strain from an strain. The decreased with this deletion. analysis AMP released into culture supernatant that appeared outside cell as intermediate consisting a mature domain carboxy terminal (C-terminal) propeptide domain. Further has loss...

Subtilisin-like proteases have been grouped into six families based on a sequence of the catalytic domain. One is kexin family, which furin representative protease. All members except one, are from eukaryotes. The one prokaryotic protease serine Aeromonas sorbria (ASP). Here, we examined substrate specificity ASP cleavage short peptides. results showed that preferentially cleaves peptide bond following two basic residues, Lys, but not single residue. This indicates tertiary structure around...

ABSTRACT Previously, we cloned the metalloprotease gene of Aeromonas sobria ( amp ) and determined its nucleotide sequence (GenBank accession number DQ784565). The protease is composed 591 amino acid residues. In this study, purified mature from culture supernatant A. terminal molecular size AMP. addition, examined production AMP diachronically found that emerges outside cell as an intermediate propeptide regions. Subsequently, N‐terminal identical to metalloprotease. This means a region...

Subtilisin-like proteases are broadly expressed in organisms ranging from bacteria to mammals. During maturation of these enzymes, N-terminal propeptides function as intramolecular chaperones, assisting the folding their catalytic domains. However, we have identified an exceptional case, serine protease Aeromonas sobria (ASP), that lacks a propeptide. Instead, ORF2, protein encoded just downstream asp, appears essential for proper ASP folding. The mechanism by which ORF2 functions remains...

For the successful production of Aeromonas sobria serine protease (ASP), open reading frame 2 (ORF2) protein, encoded at 3' end operon, is required. In this study, we examined action ORF2 protein. The results showed that protein associated with ASP in periplasm and helped to form an active structure.

The present authors have previously shown that the serine protease activity of Aeromonas sobria is markedly decreased when A. cultured in medium containing 3.0% sodium chloride (NaCl, concentration almost equivalent to sea water salinity), and this occurs because, although synthesis ASP not disturbed by salt medium, maturation pathway (ASP) does proceed successfully such a medium. In study, effect on production metalloprotease (AMP) was examined. produced AMP milieu bacteria were (NaCl) at...

ASP is the only bacterial protease in kexin group of subtilisin family. Previous studies have revealed that ORF2 protein encoded at 3' end asp operon required for to change from a nascent form into an active periplasm. However, mechanism by which makes contact and interacts with maturation process remains unknown. The present study examined effect mutations carboxy-terminal region on process. Both deletion-mutation amino acid-substitution demonstrated histidine residue position 595...

Abstract ASP is a serine protease secreted by Aeromonas sobria . cleaves various plasma proteins, which associated with onset of sepsis complications, such as shock and blood coagulation disorder. To investigate host defense mechanism against this virulence factor, we examined the for inhibitor(s). Human inhibited activity azocasein, was almost completely abolished treating methylamine, inactivates α 2 -macroglobulin (α -MG). The ASP-inhibitor complex in ASP-added not detected immunoblotting...