C. Vago

EFFECTS OF MYCOTOXINS ON INVERTEBRATE CELLS IN VITRO

Publisher Summary This chapter discusses the effects of mycotoxins on invertebrate cells in vitro . The importance of cryptogamic toxins is not only because of their ability to cause lesions at the cellular level and to kill host animals but also because of their antimicrobial and antiviral effects. Mycotoxins act by altering cells, blocking multicellular defense reactions, disturbing macromolecular syntheses, and producing antiviral effects all at once. Among the defense reactions against microbial aggression or foreign agents, the formation of granulomas may be considered one of the most important. In a study described in the chapter, cell lesions were analyzed by phase microscopy, histology, and electron microscopy. To understand the mode of action of destruxins, especially at very weak doses, further studies were conducted on their effect on cell syntheses. These studies showed that research on microbial toxins seems particularly important in its relation to cell biology, yielding indispensable information for the comprehension of the mechanisms of action of pathogenic fungi and for the perspectives that the antiviral effect introduces at the comparative virology level.

Virose a fuseaux d'un Scarabéide d'Amérique du Sud par

SummaryA new variety of spindle diseases was discovered inDemodena boranensis [Coleoptera] from Argentina. Ovoid proteinic bodies contain virions ofVagoiavirus-type but localizations in cytoplasm of ovoid and of fusiform bodies are different from those observed in spindle diseases ofMelolontha, Figulus [Coleoptera] and ofOperophtera andOreopsyche [Lepidoptera].

Dissémination des virus de polyédries par les Éphippigères prédateurs d'insectes

SummaryTransmission of polyhedral viruses byEphippiger bitterensis having ingested virus diseasedLymantria dispar larvae was observed in nature and in experiments. The passage of polyhedral bodies in different parts of the gut was studied by histological methods and the effect of the gut juice was found insignificant. These bodies were detected in dejections during 15 days after ingestion of diseased insects. Viruses were shown by electron microscope and the conservation of their pathogenic effect by infection tests. Significantion of these results in epizootiology and in biological control is discussed.

La léthargie, nouvelle virose des larves deMelolontha melolontha L. (Coléoptèrescarabaeidae)

SummaryIn larvae ofMelolontha melolontha L. [Coleoptera] an infectious disease has been observed. It is produced by a virus and characterised by a prolonged lethargic state accompanied by cytoplasmic lesions of the fat body.

Formation tumorale d’origine parvovirale chezSibine fusca [Lep.: Limacodidae]

RésuméUn état pathologique se traduisant par la formation de masses d’allure tumorale a été observé et étudié chez la larve du lépidoptèreSibine fuscaStoll ravageur des oléagineux en Colombie. La masse tissulaire résultant de la modification de la paroi de l’intestin moyen est formée par l’entassement, sans élimination, des cellules épithéliales activement multipliées sous l’influence simultanée de la régénération cellulaire liée à la fréquence des mues chez cet insecte et de la pathogénèse nucléaire d’unDensovirus.L’étude ultrastructurale montre les lésions virales nucléaires, la multiplication de type et d’intensité anormaux des cellules et la constitution à partir des cellules virosées de la masse d’allure tumorale à conséquence souvent léthale.SummaryA pathological state involving tumor-like masses was observed and studied in larvaeSibine fuscaStoll. a pest of oleaginous plants in Colombia.The tissue mass in the midgut is formed by an accumulation of non eliminated epithelial cells which rapidly multiplied under the joint effect of the cellular regeneration for the molting frequent in that insect, and of the nuclear pathogenesis of a densovirosis.Ultrastructural study revealed the nuclear viral lesions, a cell multiplication of abnormal type and frequency as well as the formation from the virus-infected cells of the tumor-like mass often lethal.