Identification of a serodiagnostic antigen, legumain, by immunoproteomic analysis of excretory-secretory products of Clonorchis sinensis adult worms.

Clonorchis sinensis, the Chinese liver fluke, is the causative agent of clonorchiasis as well as liver and biliary diseases. The excretory-secretory products (ESPs) of the parasites play important roles in host-parasite interactions. In this study, we have investigated the proteome of ESPs obtained from C. sinensis adult worms. Although the full genome database of C. sinensis is not yet available, we have successfully identified 62 protein spots using 2-DE-based mass analysis and EST database of C. sinensis. The proteins identified include detoxification enzymes, such as glutathione S-transferase and thioredoxin peroxidase, myoglobin and a number of cysteine proteases that are expressed abundantly. In order to identify potential targets for the diagnosis and therapy of clonorchiasis, we conducted immunoblot analysis of the ESPs proteome using the sera obtained from clonorchiasis patients and identified legumains and cysteine proteases as antigens present in the ESPs. Although the cysteine proteases were previously reported to elicit antigenicity, the legumains are found herein for the first time as a serological antigen of C. sinensis. To confirm these findings, we expressed recombinant legumain in Escherichia coli and verified that recombinant legumain also functions as a potent antigen against the sera of clonorchiasis patients. Our results illustrate the validity of immuno-proteomic approaches in the identification of serodiagnostic antigens in the parasites.

First case of human babesiosis in Korea: detection and characterization of a novel type of Babesia sp. (KO1) similar to ovine babesia.

We report on the first case of human babesiosis in Korea. The intraerythrocytic parasite (KO1) in the patient's blood mainly appeared as paired pyriforms and ring forms; but Maltese cross forms were not seen, and the parasite showed morphological features consistent with those of the genus Babesia sensu stricto. The sequence of the 18S rRNA gene of KO1 was closely related to that of Babesia spp. isolated from sheep in China (similarity, 98%). The present study provides the first evidence of the presence of a hitherto unidentified, new type of Babesia parasite capable of infecting humans.

A novel double-layered photobioreactor for simultaneous Haematococcus pluvialis cell growth and astaxanthin accumulation.

This study proposes a novel double-region photobioreactor to simplify the commercial two-stage process of astaxanthin production by the cultivation of Haematococcus pluvialis. The feasibility of the double-region photobioreactor has been investigated and found to achieve high biomass yield in the inner core region and simultaneous astaxanthin accumulation in the outer jacket region. Among many environmental factors, light condition and nitrate level were manipulated for selective cell growth and astaxanthin production. In the outer jacket region, efficient astaxanthin production was accomplished by excessive irradiation (770+/-20 microE m(-2)s(-1)) and nitrate starvation, resulting in a dramatic increase of astaxanthin productivity (357 mg l(-1)). Meanwhile, attenuated light energy (40+/-3 microE m(-2)s(-1)) and sufficient nitrates were supplied to the vegetative cells in the inner core region, which continued to grow to a high cell concentration of 4.0 x 10(5) cells ml(-1). The sequential batch run was performed by utilizing the high-density vegetative cells as inoculum for the next batch run. The cultivation results exhibited similar trends as the previous run, reaching high cell density (4.3 x 10(5) cells ml(-1)) in the inner core region and high astaxanthin content (5.79% on a dry weight basis) in the outer jacket region. The present study indicates that the double-region photobioreactor and its method of operation possess a good potential for commercial production of astaxanthin by H. pluvialis.