Passive transfer of resistance in rabbits infested with adult Ixodes ricinus L: humoral factors influence feeding and egg laying.

Parital immunity against the bites of female I. ricinus was transferred to normal rabbits by inoculating immune serum from resistant animals. Transferred humoral factors diminished the weight of the ticks' blood meal by 29% and increased the feeding period by about 1 day in comparison with ectoparasites engorged on controls. They provoked also the failure of egg laying by female I. ricinus. Only 55% of ticks fed on treated rabbits laid eggs (94% on controls). The immunological state of immune serum donors or recipients was studied and the IgG and homocytotropic specific anti-I. ricinus antibodies were identified. The immediate hypersensitivity of rabbits' skin was also controlled.     

Rabbits infested with adultIxodes ricinus L.: Effects of mepyramine on acquired resistance

Summary The results of this work demonstrate that histamine seems to be involved in the expression of the resistance acquired by rabbits to I. ricunus. Daily treatment of animals with the H₁-antihistaminic mepyramine inhibited the effects of immunity. This observation applies to the effect of resistance on the weight of engorged ticks, the duration of the blood meal and the success of egg laying and hatching.The present work was supported by the Swiss National Fund for Research, grant No. 3.303-78. We are grateful to Dr L. Julou (Rhône-Poulenc) for a gift of mepyramine.     

Effects and duration of resistance acquired by rabbits on feeding and egg laying in Ixodes ricinus L.

Summary Rabbits gradually developed a resistance against Ixodes ricinus ticks as a result of sequential experimental infestations. The resistance was characterized by an increased duration of feeding, by ticks engorging to a smaller extent and by reduced egg production. Once established, the immunity persisted for at least 9 months. Changes in the titre of circulating anti-I. ricinus antibodies was measured by indirect immunofluorescence.The present work was supported by the Swiss National Fund for Scientific Research, grant No. 3.558-0.75.     

Effects and duration of resistance acquired by rabbits on feeding and egg laying in Ixodes ricinus L.

Rabbits gradually developed a resistance against Ixodes ricinus ticks as a result of sequential experimental infestations. The resistance was characterized by an increase duration of feeding, by ticks engorging to a smaller extent and by reduced egg production. Once established, the immunity persisted for at least 9 months. Changes in the titre of circulating anti-I. ricinus antibodies was measured by indirect immunofluorescence.     

Passage of hemolysins through the midgut epithelium of femaleIxodes ricinus L. fed on rabbits infested or reinfested with ticks

Summary Antibodies considered in this study are hemolysins synthesized by rabbits against sheep red blood cells. Ingested with the blood meal, they cross the tick midgut epithelium and retain their immunological properties in the hemolymph. During a reinfestation of rabbits, more ticks present these antibodies, and titres are generally higher than during a first infestation. Hemolysins are only found in ticks weighing 180 mg or more.The present work was supported by the Swiss National Foundation for Scientific Research, grant No. 3070.81.     

Correlation of ammonia liberation and calcium deposition by the avian egg and blood ammonia levels in the laying hen

Zusammenfassung Mittels biochemischer Daten wird der Nachweis erbracht, dass im Ovidukt des Huhnes während der Schalenbildung zwar vermehrt NH₄ ⁺ freigesetzt wird, jedoch eine negative Korrelation zwischen NH₄ ⁺-Produktion und Ca⁺⁺-Abscheidung besteht.

---

---

Supported by a training grant from the U.S. Public Health Service No. 5-T1-DE-118. We thank Dr.P. R. Tramell for his help during the initial stage of this investigation.     

Demonstration of anaphylactic antibodies in cattle naturally infested with Hypoderma sp. (Insect. Diptera)

Anaphylactic antibodies were demonstrated in cattle parasitized by Hypoderma sp. Using a technic of passive cutaneous anaphylaxy in Goats.     

Common antigenic properties of a g-type (goose) and a c-type (duck) egg white lysozyme: Antibody responses in rabbits and mice

Embden goose (GEWL) and Barbary duck (DEWL) egg white lysozymes possess different amino acid sequences corresponding to the g-type and c-type, respectively. GEWL was shown to be a better immunogen than DEWL in both rabbits and mice. The antigenicity of the two lysozymes was tested using different technique (i.e. indirect ELISA, inhibition tests and immunoabsorption experiments). Injection of either GEWL or DEWL into rabbits and mice induced both specific antibodies and cross-reacting antibodies. Moreover, anti-GEWL antibodies, in contrast to anti-DEWL antibodies, did not cross-react with hen egg white lysozyme (HEWL), a c-type lysozyme. While the structure of GEWL was not modified after binding to plastic, DEWL was denaturated, but it did keep some native epitopes. It was concluded that g-type and c-type lysozymes, which have different amino acid sequences, exhibit strong common antigenic properties.     

The influence of maltose and other carbohydrates on the feeding behaviour ofHeteronychus arator (Scarabaeidae: Coleoptera)

Summary Several of 17 carbohydrates stimulated ingestion by black beetle larvae (Heteronychus arator) and of these maltose induced an exceptionally strong response. Only maltose, glucose, fructose and sucrose stimulated feeding by adult beetles.     

Effects of dihydroergocriptine on mouse and rat resistance to acute anoxia: influence of repetition of treatment

Summary The antihypoxic activity of DHEC mesylate, as evaluated in mice and rats submitted to hypobaric hypoxia and to asphyxic anoxia respectively, is noticeably stronger when the compound is administered according to a repeated treatment schedule than when administered only once. The results correlate well with human clinical observations.     

The influence of ambient temperature on thermoregulatory responses to intraventricularly injected monoamines in sheep,goats and rabbits

Zusammenfassung Zur Erklärung der Effekte auf die Thermoregulation in Schafen, Ziegen und Kaninchen bei verschiedenen Umwelttemperaturen von intraventrikulären Injektionen von Noradrenalin (NA) und 5-Hydroxytryptamin (5-HT) wurde ein einfaches Neuronenmodell vorgeschlagen. Diese Monoamine entfalten nicht in allen Situationen eine reziproke Wirkung. 5-HT führt zu einem Anstieg des Wärmeverlustes und einer Hemmung der Wärmebildung. NA hemmt sowohl Wärmeverlust wie auch Wärmebildung 19.