Background: While immune responses to the murine hookworm Nippostrongylus brasiliensis have been investigated, signaling pathways regulating development of infectious larvae (iL3) are not well understood. We hypothesized that N. brasiliensis would use pathways similar to those controlling dauer development in the free-living nematode Caenorhabditis elegans, which is formally known as the "dauer hypothesis. " Methods: To investigate whether dafachronic acid activates the N. brasiliensis DAF-12 homolog, we utilized an in vitro reporter assay. We then utilized RNA-Seq and subsequent bioinformatic analyses to identify N. brasiliensis dauer pathway homologs and examine regulation of these genes during iL3 activation. Results: In this study, we demonstrated that dafachronic acid activates the N. brasiliensis DAF-12 homolog. We then identified N. brasiliensis homologs for members in each of the four canonical dauer pathways and examined their regulation during iL3 activation by either temperature or dafachronic acid. Similar to C. elegans, we found that transcripts encoding antagonistic insulin-like peptides were significantly downregulated during iL3 activation, and that a transcript encoding a phylogenetic homolog of DAF-9 increased during iL3 activation, suggesting that both increased insulin-like and DAF-12 nuclear hormone receptor signaling accompanies iL3 activation. In contrast to C. elegans, we observed a significant decrease in transcripts encoding the dauer transforming growth factor beta ligand DAF-7 during iL3 activation, suggesting a different role for this pathway in parasitic nematode development. Conclusions: Our data suggest that canonical dauer pathways indeed regulate iL3 activation in the hookworm N. brasiliensis and that DAF-12 may be a therapeutic target in hookworm infections.

This paper introduces a practical implementation of the normalized dynamic energy stability margin (NDESM) which is simplified for wheeled mobile robots. Several types of sensors are generally required to measure the stability margin of a robot. This makes the practical implementation of a stability measurement system complicated. The simplified stability margin can be measured with only a few sensors, and it describes both static and dynamic effects on stability. The performance of the simplified stability margin is demonstrated through dynamic simulations. The experimental results and an implementation of the stability margin measurement system on a real robot are also presented.

This paper presents mechanism and control algorithm for inch worm type in-pipe robot using three helical springs. Control algorithm is based on experiment result and length of three spring are derived from desired position of top module. A feasibility of proposed mechanism is verified by comparing between ellipse model and position of top module, and it shows that proposed mechanism can steer properly.

This paper presents a new mechanical design of mobile robot which can travel in the condition of continuous varying environment, such as colon of human body. Especially, the human colon environment contains an intense diameter change. The suggested mechanical design is capable to adapt in wide diameter changing system by generating two basic motions, rotational and linear motion, with a single actuator. Prototypes is fabricated, and tested result is presented in this paper. Also, experimental result is compared with the mathematical model of the mechanism to verify the feasibility of the proposed mechanism.