Subterranean termites build extensive underground galleries consisting of elaborate tunnels and channels to forage food resources. Diverse soil conditions surrounding the tunnels, such as soil density, may cause irregularities in the size and shape of the tunnels, and termites are likely to encounter a number of tunnel irregularities while traveling. Considering the tunnel length, how termites respond to an irregularity is likely to affect their movement efficiency, and this in turn is directly correlated to their foraging efficiency. To understand the response of termites, we designed an artificial linear tunnel with rectangular irregularities in a 2-D arena. The tunnel widths, W, were 3 and 4 mm. The rectangular irregularities were 2 mm in width and of varying heights H (2, 1, 0, -1, and -2 mm). The positive and negative sign of H represents a convex and concave structure, respectively. We systematically observed the movement of termites, Coptotermes formosanus Shiraki, at the irregularity and quantified the time needed, τ, for a termite to pass the irregularity. The time τ was shorter for (W, H) = (3, 0) and (3, -1) than for (W, H) = (3, 1), (3, 2), and (3, -2). The time τ was longer for (W, H) = (4, -1), and (4, -2), than for (W, H) = (4, 0), (4, 1) and (4, 2). Four types of behaviors explained the response to the irregularity. The implications of these findings are briefly discussed in relation to termite foraging efficiency.

A full genomic DNA microarray technique was employed to investigate the effects of Dongchunghacho on aortal and hepatic gene expression in apolipoprotein E knockout mice fed a high-fat/high-cholesterol diet. Male 8- week - old ApoE-/- mice were randomly divided into two groups, control(high cholesterol group; HC) and supplementation of Dongchunghacho (SD). All of the mice were fed a high-fet/high cholesterol diet with or without Dongchunghacho supplemented by 1% for 6 weeks. At first, lipid profile of the Dongchunghacho was measured by biochemical analysis. No differences were observed in serum triglyceride and total cholesterol levels between the two groups. Antigenotoxic effect of the Dongchunghacho was measured by the single cell gel electrophoresis assay (Comet assay) and quantified as % fluorescence in tail. Dongchunghacho supplementation decreased significantly leukocytic DNA damage and also there was a tendency of reduction in hepatic DNA damage in Dongchunghacho group compared with the control group. In up regulated genes in liver and aorta of the mice, genes with 0 to 2- fold difference in expression level between the two group (HD and SD) was very much more in liver than in aorta, on the contrary, those with 2-fold to 16-flod difference increased greatly rather in aorta than in liver. Also, almost the same results were observed in down regulated genes in liver and aorta between the two groups. These results suggested that supplementation of Dongchunghacho might be helpful in preventing leukocytic DNA damage induced by high fat diet, and has a more crucial roles in aortal gene expression.

Subterranean termites construct complicated tunnel network for foraging below the ground. Thus, they often encounter a number of tunnel intersections during their moving from place to place in the network. In order to understand how termites respond to the intersections, we artificially excavated two tunnels intersected with 90° degree in soil-filled arenas. The two tunnels had the width of W1 and W2 (=2, 3, and 4mm), respectively. We systematically observed the response behavior of advancing termites to the intersection with the combination of W1 and W2, (W1, W2). For (W1, W2)=(2, 2) and (3, 3), the advancing termites passed the intersection without directional changes because it was difficult for termites to bend their body to change their moving direction due to the small-sized width. For (W1, W2)=(4, 4), the termites statistically-equally chose the three directions, left, right, and straight, which was due to the fact that the intersection provided enough space for termites to bend. For (W1, W2)=(2, 3), (2, 4), and (3, 4), termites, advancing in narrower tunnels, tended considerably to turn right or left, while termites, advancing in wider tunnels, were favorably inclined to go straight. These results can be understood by considering the relationship between termite body length and tunnel width as explained for the cases of W1=W2. In addition, we briefly discussed our findings in relation to termite foraging efficiency.