Insect Symbionts Research Articles

Cellulolytic activity of bacterial symbionts of wood-destroying insects.

Cellulolytic activity of bacterial symbionts of wood-destroying insects.

Aufzuchtversuche an Lasioderma serricorne F. in Drogen- und Holzpulvern im Hinblick auf die Rolle der hefeartigen Symbionten / Rearing experiments with Lasioderma serricorne F. in drug and wood powders with special reference to the role of yeastlike symbionts

Growth of normal and aposymbiotic larvae of Lasioderma serricorne F. (Coleoptera. Anobiidae) was compared in drug and wood powders with and without addition of 5% vitamin-free casein and/or a complete vitamin mixture. The loss of endosymbionts caused a more or less significant growth retardation which was compensated by casein but not by vitamins. It is therefore necessary to correct the opinion that symbionts of phytophagous insects are vitamin sources for their hosts. Furnishing of vitamins may be of some importance in wood-boring insects and species feeding on certain stored products, but the main part played by symbionts must be in the protein metabolism of their hosts.

A Case of Tuberculous Rheumatism: Grocco-Poncet Type

<h3>Abstract</h3> <i>Wolbachia pipientis</i> is an incredibly widespread bacterial symbiont of insects, present in an estimated 25-52% of species worldwide. <i>Wolbachia</i> is faithfully maternally transmitted both in a laboratory setting and in the wild. In an established infection, <i>Wolbachia</i> is primarily intracellular, residing within host-derived vacuoles that are associated with the endoplasmic reticulum. However, <i>Wolbachia</i> also frequently transfer between host species, requiring an extracellular stage to their life cycle. Indeed, <i>Wolbachia</i> has been moved between insect species for the precise goal of controlling populations. The use of <i>Wolbachia</i> in this application requires we better understand how it initiates and establishes new infections. Here we designed a novel method for live-tracking <i>Wolbachia</i> during infection using a combination of stains and microscopy. We show that live <i>Wolbachia</i> are taken up by host cells at a much faster rate than dead <i>Wolbachia</i> cells, indicating that <i>Wolbachia</i> play a role in their own uptake and that <i>Wolbachia</i> colonization is not just a passive process. We also show that the host actin cytoskeleton must be intact for this to occur, and that drugs that disrupt the actin cytoskeleton effectively abrogate <i>Wolbachia</i> uptake. The development of this live infection assay will assist in future efforts to characterize <i>Wolbachia</i> factors used during host infection.

Intracellular Symbionts of Insects as a Source of Vitamins

IN our previous communication on the vitamins of the B group required by insects1, we pointed out that the difference in the vitamin requirements of two groups of beetles, one comprising Tribolium and Ptinus, and the other Lasioderma, Sitodrepa and Silvanus, was possibly due to the presence, in the latter group, of intracellular symbionts. Tribolium, Ptinus and (unpublished) the moth Ephestia elutella require thiamin, riboflavin, nicotinic acid, pyridoxine and pantothenic acid, and, to a lesser degree, choline chloride and biotin as essential growth factors. Lasioderma, Sitodrepa and Silvanus grow successfully in the absence of some of these vitamins, although their requirements differ in detail. The growth of normal larvae of Lasioderma serricorne and Sitodrepa panicea and of Ptinus tectus on diets containing all the chemically known factors of the vitamin B complex in pure substance (whole diet) and on diets which were lacking in one single B factor are shown in the accompanying.