Anaerobic respiration and antioxidant responses of Corythucha ciliata (Say) adults to heat-induced oxidative stress under laboratory and field conditions.

High temperature often induces oxidative stress and antioxidant response in insects. This phenomenon has been well documented under controlled laboratory conditions, but whether it happens under fluctuating field conditions is largely unknown. In this study, we used an invasive lace bug (Corythucha ciliata) as a model species to compare the effects of controlled thermal treatments (2 h at 33-43 °C with 2 °C intervals in the laboratory) and naturally fluctuating thermal conditions (08:00-14:00 at 2-h intervals (29.7-37.2 °C) on a hot summer day in a field in Shanghai, China) on lipid peroxidation (malondialdehyde (MDA) was the marker) and anaerobic respiration (lactate dehydrogenase (LDH) was the marker), as well as superoxide dismutase (SOD), catalase (CAT), glutathione (GSH), and glutathione reductase (GR). The results show that MDA concentration increased significantly in response to heat stresses with similar trend in the laboratory and field. LDH activities did not significantly vary across temperatures in the laboratory-exposed individuals, but they significantly increased by rising temperature in the field. The activities or concentrations of SOD, CAT, GSH, and GR all significantly increased with increasing temperature in the two populations. These findings indicate that high temperature induces oxidative stress, resulting in high anaerobic respiration and antioxidant defenses in C. ciliata under both the laboratory and field conditions, which likely provide a defense mechanism against oxidative damage due to the accumulation of ROS.

[Anti-complement activity of polysaccharide B3-PS2 purified from Herba Scutellariae Barbatae].

The polysaccharide B3-PS2 was extracted and purified from Herba Scutellariae Barbatae through chromatography of DEAE-cellulose and Sephacryl S-300 column. Average molecular weight of B3-PS2 was about 1,100 kD. It was composed of Glc, Gal and Ara in the ratio of 2.7:2.7:1.0, along with trace of Man, Rha, Fuc and Xyl. B3-PS2 inhibited complement activation on the classic pathways with CH50 value of (0.23 +/- 0.03) mg mL(-1). The targets of B3-PS2 upon the complement system were C1r, C1s, C3 and C4. These results suggested that anti-complementary activity of B3-PS2 was closed to its positive control heparin. It strongly suggested that the polysaccharide B3-PS2 from Herba Scutellariae Barbatae could be a potential candidate in treating those complement-associated diseases.