Studies on chemotherapy of parasitic helminths (V). Effects of niclosamide on the motility of various parasitic helminths

Summary Niclosamide, a well-known antitapeworm drug, caused spastic and/or paralytic actions on the motility of various preparations including parasitic cestodes, trematodes, nematodes, and host isolated tissues.     

Effects of Avermectin Bla on the motility of various parasitic helminths

Summary Using an isotonic transducer recently devised in Japan, it was observed that Avermectin Bla, a new anthelmintic, caused paralyzing effects onAngiostrongylus cantonensis andMetastrongylus elongatus at concentrations of more than 3.6×10^–18 M.     

Prophenolase and the role of Mehlis' gland in helminths

Zusammenfassung Die Phenoloxydase der Vittellinzellen von Trematoden wirkt als inaktive Prophenoloxydase und bedingt, dass die von Dotterstockzellen synthetisierten Vorläufer von Sklerotin in situ nicht tanniert werden. Das Sekret der Mehlis-Drüse beeinflusst die Fermentaktivierung.     

Odour preference of a parasitic wasp depends on order of learning

FemaleLeptopilina boulardi wasps, larval parasites ofDrosophila melanogaster, can learn to respond to more than one odour by associating these odours with oviposition experience. These wasps can memorise and respond to at least two different odours, and prefer the last one learnt.     

Enemy-induced dispersal in a parasitic wasp

Females of the parasitic waspAphidius uzbekistanicus, a specialist aphid primary parasitoid, react to the presence of their specialist hyperparasitoid enemyAlloxysta victrix by leaving the area. The wasps leave to increase their reproductive success, because only their offspring, but not the wasps themselves, are threatened by enemy attack. Furthermore, this dispersal is elicited through the action of volatile chemical cues produced by the hyperparasitoids. We provide evidence for 6-methyl-5-hepten-2-one being one of the volatiles eliciting dispersal. The tendency of the wasps to leave areas which are being colonized by their enemies reduces their efficiency as aphid antagonists.     

Catalase in free-living and parasitic platyhelminths

Summary Catalase was found in all of the free-living species of platyhelminths studied, but could not be detected in any of the parasitic species (trematodes or cestodes). This work was supported by NATO research grant 1681.     

Regulation of tryptophan metabolism in the parasitic wasp,Habrobracon juglandis

Zusammenfassung Die Metabolite und 3 Enzyme des Tryptophanstoffwechsels vonHabrobracon weisen während der parasitären Phase sowie während der Puppenruhe und im Imaginalstadium signifikante Konzentrations-bzw. Aktivitätsveränderungen auf. Diese sind das Ergebnis mindestens zweier Regulationsmechanismen.

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I thank Prof.V. Schwartz and Prof.A. Egelhaaf for helpful advice.     

Activity of contractile vacuole in the parasitic ciliate,Balantidium coli

Résumé Chez leBalantidium coli, la vacuole contractile se remplit graduellement et s'agrandit. Après une phase stationnaire, pendant laquelle elle reste irrégulière en apparence, elle se gonfle entièrement, devient sphérique, et puis s'affaisse subitement et expulse son contenu. L'affaissement est très rapide et ne prend qu'une fraction de seconde. Le cycle entier dure générallement 20 à 25 secondes.     

Isolation and partial characterization of cuticular collagen from the parasitic nematodeGaigeria pachyscelis

Summary The cuticle from adultGaigeria pachyscelis was isolated by solubilizing the internal tissues with sodium dodecyl sulphate (SDS) at 37°C. Cuticular protein was extracted with guanidine-HCl and -mercaptoethanol and purified by ammonium sulphate fractionation and DEAE-cellulose chromatography. SDS-polyacrylamide gel electrophoresis of purified protein revealed 2 polypeptides with apparent mol. wts of 58,000 and 74,000. As judged from their hydroxyproline content both of them are collagenous in nature. Results of gel filtration indicate that cuticular collagen exists in two forms, a non-associated form at low concentration and an associated form at high concentration.Acknowledgments. We thank Drs L.N. Singh and H.C. Tewari for providing the necessary facilities. Laboratory assistance of Mr Ram Kishore is highly appreciated.     

Action of sodium pyruvate upon nucleated and enucleated fragments of the parasitic ciliateOpalina ranarum

Zusammenfassung Natrium-Pyruvat zeigt eine cytolisierende Wirkung auf enukleierte Fragmente der schmarotzenden CiliateOpalina ranarum.     

Infection of frog tadpoles (Amphibia) by insect parasitic nematodes (Rhabditida)

Summary Infective stage juveniles ofNeoaplectana carpocapsae (Steinernematidae) andHeterohabditis heliothidis (Heterorhabditidae) were able to penetrate through the alimentary tract of young tadpoles ofHyla regilla (Hylidae) andXenopus laevis (Pipidae) and enter the body cavity. Some infectives ofN. carpocapsae were able to release their symbiotic bacterium,Xenorhabdus nematophilus inside the host and in two cases, the nematodes developed into adult females before they perished. Tadpole mortality was associated with foreign bacteria entering the penetration holes made by the invading nematodes. The infective stage juveniles of both nematodes frequently encountered a host defense reaction upon reaching the tadpole's infective stage juveniles of both nematodes frequently encountered a host defense reaction upon reaching the tadpole's coelom.