Acta Medica Okayama4482004Generation of active fragments from human zymogens in the bradykinin-generating cascade by extracellular proteases from Vibrio vulnificus and V. parahaemolyticus887893ENShin-ichiMiyoshiHirofumiWatanabeTomokaKawaseHidenoriYamadaSumioShinoda<p>Vibrio vulnificus is an opportunistic human pathogen causing septicemia, and the infection is
characterized by formation of the edematous skin lesions on limbs. This pathogenic species
secretes a thermolysin-like metalloprotease as a virulence determinant. The metalloprotease
was confirmed to activate human factor XII-plasma kallikrein-kinin cascade that results in
liberation of bradykinin, a chemical mediator enhancing the vascular permeability, from
high-molecular weight kininogen. Namely, the metalloprotease showed to generate active
fragments by cleavage of Arg-Ile, Arg-Val or Gly-Leu peptide bond in human zymogens
(plasma prekallikrein and factor XII). In spite of induction of the sufficient vascular
permeability-enhancing and edema-forming reaction in the guinea pig model, a serine
protease from V. parahaemolyticus, a human pathogen causing primarily watery diarrhea,
showed far less ability to activate and to cleave the human zymogens. These results in part
may explain why only V. vulnificus often causes serious edematous skin damages in humans.</p>No potential conflict of interest relevant to this article was reported.Acta Medica Okayama20742004Purification and cDNA cloning of the ovigerous-hair stripping substance (OHSS) contained in the hatch water of an estuarine crab Sesarma haematocheir 621632ENOlegGusevHidekiIkedaTetsushiOkochiJae MinLeeMasatsuguHatakeyamaChiyokoKobayashiKiyokazuAgataHidenoriYamadaMasayukiSaigusa<p>The egg attachment system of an estuarine crab
Sesarma haematocheir is formed on the maternal
ovigerous hairs just after egg laying, and slips off these
hairs just after hatching. The stripping is caused by an
active factor that we call OHSS (ovigerous-hair stripping
substance), which is released by the embryo upon
hatching. OHSS was purified, and its active form had a
molecular mass of 25·kDa. The cDNA of OHSS cloned
from an embryonic cDNA library was 1759·bp long,
encoding 492 amino acids in a single open reading frame
(ORF). The C-terminal part of the predicted protein was
composed of a trypsin-like serine protease domain, with
homology to counterparts in other animals of 33–38%.
The predicted protein (54.7·kDa) secreted as a zymogen
may be cleaved post-translationally, separating the Cterminal
from the N-terminal region. The OHSS gene was
expressed in the embryo at least 2 weeks before hatching.
Expression was also detected in the zoea larva 1 day after
hatching and in the brain of the female. However, it was
not detected in the muscle, hepatopancreas or ovigerous
seta of the female. Ultrastructural analysis indicated that
the material investing maternal ovigerous hair, i.e. the
outermost layer (E1) of the egg case, is attached at the
special sites (attachment sites) arranged at intervals of
130–160·nm on the hair. It is suggested that OHSS acts
specifically at these sites, lysing the bond with the coat,
thus disposing of the embryo attachment system. This
enables the female to prepare the next clutch of embryos
without ecdysis.</p>
No potential conflict of interest relevant to this article was reported.