Little is known about how tropical land-use systems contribute to the conservation of functionally important insect groups, including dung beetles. In a study at the margin of Lore Lindu National Park (a biodiversity hotspot in Central Sulawesi, Indonesia) dung-beetle communities were sampled in natural forest, young secondary forest, agroforestry systems (cacao plantations with shade trees) and annual cultures (maize fields), each with four replicates (n ¼ 16 sites). At each site we used 10 pitfall traps, baited with cattle dung, along a 100 m transect for six 3-day periods. The number of trapped specimens and species richness at the natural forest sites was higher than in all land-use systems, which did not significantly differ. Each land-use system contained, on average, 75% of the species richness of the natural forest, thereby indicating their importance for conservation. However, a two-dimensional scaling plot based on NESS indices (m ¼ 6) indicated distinct dung beetle communities for both forest types, while agroforestry systems and annual cultures exhibited a pronounced overlap. Mean body size of dung beetles was not significantly influenced by land-use intensity. Five of the six most abundant dung beetle species were recorded in all habitats, whereas the abundance of five other species was significantly related to habitat type. Mean local abundance and number of occupied sites were closely correlated, further indicating little habitat specialisation. The low dung beetle diversity (total of 18 recorded species) may be due to the absence of larger mammals in Sulawesi during historical times, even though Sulawesi is the largest island of Wallacea. In conclusion, the dung beetle fauna of the lower montane forest zone in Central Sulawesi appears to be relatively robust to man-made habitat changes and the majority of species did not exhibit strong habitat preferences.

The naturally occurring flavonoid, quercetin, in the presence of Cu(II) and molecular oxygen caused breakage of calf thymus DNA, supercoiled pBR322 plasmid DNA and single-stranded M13 phage DNA. In the case of the plasmid, the product(s) were relaxed circles or a mixture of these and linear molecules depending upon the conditions. For the breakage reaction, Cu(II) could be replaced by Fe(III) but not by other ions tested [Fe(II), Co(II), Ni(II) and Ca(II)]. Structurally related flavonoids, rutin, galangin, apigenin and fisetin, were ineffective or less effective than quercetin in causing DNA breakage. In the case of the quercetin--Cu(II) reaction, Cu(I) was shown to be an essential intermediate by using the Cu(I)-sequestering reagents, neocuproine and bathocuproine. By using Job plots we established that, in the absence of DNA, five Cu(II) ions can be reduced by one quercetin molecule; in contrast, two ions were reduced per quercetin molecule in the DNA breakage reaction. Equally neocuproine inhibited the DNA breakage reaction. The involvement of active oxygen in the reaction was established by the inhibition of DNA breakage by superoxide dismutase, iodide, mannitol, formate and catalase (the inhibition was complete in the last case). From these data we propose a mechanism for the DNA strand scission reaction of quercetin and related flavonoids.

The genotoxic flavonoid, quercetin, was shown to bind to both double-stranded and single-stranded DNA with concomitant changes in absorption spectrum and fluorescence emission spectrum of quercetin. Quercetin and Cu(II) were shown to form a charge transfer complex that decayed in oxygen-dependent reaction(s) and this decay was accelerated by DNA. Analysis of the three component system, DNA--querectin--Cu(II), led to a discussion of the complexes likely to be involved in the initial reactions that lead, ultimately, to strand scission of DNA.

Polycyclic aromatic molecules such as ellipticine intercalate into double-stranded DNA and interfere with physiological functions. In the present study, we evaluate the chemotherapeutic potential of MPTQ on animal models and its mode of action. In order to test the antitumor activity, monohydrochloride of MPTQ was orally administered in mice bearing tumor. Results showed a significant inhibition of tumor growth compared to that of untreated controls. More importantly, mean lifespan of tumor bearing animals treated with MPTQ was significantly higher as compared to that of untreated tumor bearing mice suggesting that the treatment affected viability of cancerous cells, but not of normal cells. Consistent with this, we find that administration of MPTQ to normal mice did not cause any major side effects as observed upon hematological and serum profiling. We also found that MPTQ induces cytotoxicity in cancer cell lines, by activating apoptosis both by intrinsic and extrinsic pathways. Thus, MPTQ could be used as a potential cancer therapeutic agent.

Abstract:Dung beetles are a functionally important component of most terrestrial ecosystems, but communities change with habitat disturbance and deforestation. In this study, we tested if dung beetle ensembles on dung of introduced cattle and of the endemic anoa, a small buffalo, are affected differentially by habitat disturbance. Therefore, we exposed 10 pitfall traps, five baited with anoa and five baited with cattle dung, per site in six habitat types ranging from natural and selectively logged rain forest to three types of agroforestry system (characterized by different management intensity) and open areas (n = 4 replicate sites per habitat type) at the margin of Lore Lindu National Park, Central Sulawesi, Indonesia. We found 28 species, 43% of which were endemic to Sulawesi. Species richness, abundance and biomass declined from natural forest towards open area. Large-bodied species appeared to be more sensitive to habitat disturbance and the ratio of large to small-sized dung beetles declined with land-use intensity. Although selectively logged forest and cocoa agroforestry systems had lower species richness compared with natural forest, they appeared to maintain a high portion of species originally inhabiting forest sites. The similarity of dung beetle ensembles recorded at forest and agroforestry sites reflects the high similarity of some habitat variables (e.g. vegetation structure and microclimate) between both habitat types compared with open areas. Species richness and abundances as well as species composition, which was characterized by decreases in mean body size, changed with land-use intensity, indicating that dung type is less important than habitat type for determining ensemble structure of these Indonesian dung beetles.