A New 1,5-Dihydroxy-4-methoxyisoquinoline from Scolopendra subspinipes mutilans.

A new isoquinoline, 1,5-dihydroxy-4-methoxyisoquinoline (1), was obtained from Scolopendra subspinipes mutilans. Compound 1 showed moderate cytotoxicity on tumour cells with IC50 values ranging from 13 to 26 µm against five esophageal squamous cancer cells whereas low cytotoxicity against normal human esophageal epithelial cells. Isoquinoline ring oxidized at C(1), C(4), and C(5) can enhance its cytotoxicity. In addition, compound 1 showed potent inhibitory effect (inhibition rate > 50% at 13 µm) on cell migration in human umbilical vein endothelial cells. This article mainly studies the structure and activity of 1, and more modification of 1 as a potential anticancer agent.

The endoparasitoid Psyllaephagus arenarius benefits from ectoparasitic venom via multiparasitism with the ectoparasitoid Tamarixia lyciumi.

As solitary nymphal parasitoids of Paratrioza sinica, the ectoparasitoid Tamarixia lyciumi and the endoparasitoid Psyllaephagus arenarius act as effective biocontrol agents. Thus, it is necessary to facilitate mass productions of both species. Despite showing an excellent parasitic ability, Ps. arenarius is often trapped fatally inside 5th-instar nymphs of Pa. sinica due to strong host immunity. To improve the emergence rate of Ps. arenarius, we evaluated whether Ps. arenarius could utilize T. lyciumi venom via multiparasitism, so the parasitism characteristics of both species were examined between separate-existence (monoparasitism only) and co-existence (mono- and multiparasitism) systems. Further, the parasitism characteristics of Ps. arenarius on venom-injected hosts with/without T. lyciumi eggs were tested to further identify the facilitator. The results showed the parasitism rate of T. lyciumi was increased while that of Ps. arenarius did not change from separate-existence to co-existence systems. The intrinsic performances of two species in monoparasitism did not differ between separate- and co-existence systems. From monoparasitism (separate-existence) to multiparasitism (co-existence), no differences were detected in the intrinsic performances of T. lyciumi, but those of Ps. arenarius were greatly improved. After T. lyciumi venom injection, the parasitism characteristics of Ps. arenarius did not differ between venom-injected hosts with T. lyciumi eggs and those without, further indicating Ps. arenarius benefited from the venom of T. lyciumi females rather than T. lyciumi egg/larval secretions. Instead of negative effects, multiparasitism with ectoparasitoids improves endoparasitoids due to ectoparasitic venom. The study increases host resource utilization and provides creative ways for mass production of endoparasitoids.

[Predation of Poratrioza sinica Yang Li by the adults of Coccinella septempunctata.] / 七星瓢虫成虫对枸杞木虱的捕食作用.

To study predation by Coccinella septempunctata adults on 4 stages of Poratrioza sinica Yang Li, predation functional response, mutual interference, density influence and preference of C. septempunctata on P. sinica were investigated in laboratory and preying effect in field. The study indicated that functional response of adult C. septempunctata to P. sinica could be fitted by Holling 2 model, the daily maximum numbers of P. sinica eggs, 1st-2nd instar nymphs, 3rd-5th instar nymphs and adults preyed theoretically by the adult C. septempunctata were 112.6, 536, 415 and 113.9, respectively. In 30 days of adult's life cycle, density of P. sinica inside cages could be decreased by 80.1% in the field. Searching efficiency of C. septempunctata to P. sinica 1st-2nd instar nymphs was 0.9451 and processing time was 0.001865, which were better than those of other stages. The maximum rate of P. sinica 1st-2nd instar nymphs preyed was 80.2% as the prey density was 100 heads per dish, so the ratio of predator: prey was 1:100. The density had a greater impact than mutual interference on C. septempunctata. When different stages of P. sinica co-existed equally, C. septempunctata preferred P. sinica adult in 100 heads per dish while P. sinica nymphs in 300 heads per dish. The study showed that C. septempunctata has the potential to be predator of P. sinica and the newly-hatched nymphs could be controlled more effectively by C. septempunctata adult in field.