background: autophagy as a cellular pathway facilitates several immune responses against infection. it also eliminates invading pathogens through transferring content between the cytosol and the lysosomal vesicles and contributes to the cross-presentation of exogenous antigens to t lymphocytes via mhc class i pathway. autophagy induction is one of the main targets for new drugs and future vacci...

The specificity of substrates for measuring cystyl-amino peptidase activity in pregnant serum in the assessment of placental function was studied, using £-cystine-di-j3-naphthylamide, L-cystine-bis-/?-nitroanilide,/,-cysteine-j3naphthylamide, and S-benzyl-i-cysteine-p-nitroanilide. The enzyme activity with S-benzyl-Z,-cysteine-/?-nitroanilide increased more rapidly and markedly than with other ...

Phytomonas serpens, a phytoflagellate trypanosomatid, shares common antigens with Trypanosoma cruzi. In the present work, we compared the hydrolytic capability of cysteine peptidases in both trypanosomatids. Trypanosoma cruzi epimastigotes presented a 10-fold higher efficiency in hydrolyzing the cysteine peptidase substrate Z-Phe-Arg-AMC than P. serpens promastigotes. Moreover, two weak cystein...

Naegleria fowleri, a free-living ameba, is the causative agent of Primary Amebic Meningoencephalitis. Highly pathogenic mouse-passaged amebae (Mp) and weakly pathogenic axenically grown (Ax) N. fowleri were examined for peptidase activity. Zymography and azocasein peptidase activity assays demonstrated that Mp and Ax N. fowleri exhibited a similar peptidase pattern. Prominent for whole cell lys...

BACKGROUND Schistosomiasis, a severe disease caused by parasites of the genus Schistosoma, is prevalent in 74 countries, affecting more than 250 million people, particularly children. We have previously shown that the Schistosoma mansoni gut-derived cysteine peptidase, cathepsin B1 (SmCB1), administered without adjuvant, elicits protection (>60%) against challenge infection of S. mansoni or S. ...

Xanthomonas citri subsp citri (Xac) is the bacterium responsible for citrus canker disease in citrus plants. The aim of this study was to describe the recombinant expression, purification, and characterization of a cysteine peptidase from Xac strain 306, which is a candidate for involvement in the pathogenicity of this bacterium. The gene was cloned and expressed in Pichia pastoris, and the cys...

We report that a thiol leader peptidase, produced by replacing the critical serine at position 90 with a cysteine residue, is enzymatically active. In contrast to the wild-type leader peptidase, the thiol enzyme can be inactivated with N-ethylmaleimide, a cysteine-specific reagent. This strongly suggests that the serine 90 is involved in catalysis and is located at the active site. Of the three...

The red flour beetle, Tribolium castaneum, is a major agricultural pest responsible for considerable loss of stored grain and cereal products worldwide. T. castaneum larvae have a highly compartmentalized gut, with cysteine peptidases mostly in the acidic anterior part of the midgut that are critical to the early stages of food digestion. In previous studies, we described 26 putative cysteine p...

Cercariae of the bird schistosome Trichobilharzia regenti and of the human schistosome Schistosoma mansoni employ proteases to invade the skin of their definitive hosts. To investigate whether a similar proteolytic mechanism is used by both species, cercarial extracts of T. regenti and S. mansoni were biochemically characterized, with the primary focus on cysteine peptidases. A similar pattern ...

BACKGROUND Parasite peptidases have been actively studied as vaccine candidates or drug targets for prevention or treatment of parasitic diseases because of their important roles for survival and/or invasion in the host. Like other parasites, the facultative histophagous ciliate Miamiensis avidus would possess peptidases that are closely associated with the invasion into the host tissue and sur...