Disloyalty and treachery in bug-swapping shocker!

Diversity in gut microflora of Helicoverpa armigera populations from different regions in relation to biological activity of Bacillus thuringiensis δ-endotoxin Cry1Ac

Transgenic crops expressing toxin proteins from Bacillus thuringiensis (Bt) have been deployed on a large scale for management of Helicoverpa armigera. Resistance to Bt toxins has been documented in several papers, and therefore, we examined the role of midgut microflora of H. armigera in its susceptibility to Bt toxins. The susceptibility of H. armigera to Bt toxin Cry1Ac was assessed using Log-dose-Probit analysis, and the microbial communities were identified by 16S rRNA sequencing. The H. armigera populations from nine locations harbored diverse microbial communities, and had some unique bacteria, suggesting a wide geographical variation in microbial community in the midgut of the pod borer larvae. Phylotypes belonging to 32 genera were identified in the H. armigera midgut in field populations from nine locations. Bacteria belonging to Enterobacteriaceae (Order Bacillales) were present in all the populations, and these may be the common members of the H. armigera larval midgut microflora. Presence and/or absence of certain species were linked to H. armigera susceptibility to Bt toxins, but there were no clear trends across locations. Variation in susceptibility of F1 neonates of H. armigera from different locations to the Bt toxin Cry1Ac was found to be 3.4-fold. These findings support the idea that insect migut microflora may influence the biological activity of Bt toxins.

Microbiology of the gut of the kola nut weevil, Balanogastris kolae

Reports have shown that many insects have microbes in their gut system. Gut microbes are very important for insect vitality and much of their nutrition is derived from products of microbial metabolism. The habitat of Balanogastris kolae (Desbrocher des Loges) (Coleoptera: Curculionidae) suggests that they possess the ability to digest varieties of sugars particularly starch and protein materials present in the kola nut, Cola nitida Schott & Endlicher (Malvales: Malvaceae). The aim of this study was to characterize the gut bacterial communities of the kola weevil, B. kolae. To ascertain this, the gut bacterial community of a kola nut-feeding weevil, B. kolae was characterized using culture-dependent methods. The bacterial counts in the foregut, midgut and hindgut were 7.14 ± 0.11 × 10(6)cfu ml(-1), 2.68 ± 0.13 × 10(7) cfu ml(-1) and 1.43 ± 0.20 × 10(6) cfu ml(-1) respectively. There were no significant differences in the total bacterial count of the foregut, midgut and hindgut. The bacterial species were identified to be Fusobacterium nucleatum, Staphylococcus aureus, Bacillus subtilis, Corynebacterium fascians, Arthrobacter globiformis, Serratia marcescens, Bacillus brevis, Vibrio haemolyticus and Flavobacterium breve. The majority of these isolates were demonstrated to have both proteolytic and amylolytic activities.

Application of 16S rDNA-DGGE to examine the microbial ecology associated with a social wasp Vespula germanica

Invertebrates host numerous bacteria, with interactions ranging from pathogenesis to symbiosis. While certain symbiotic relationships have been well studied, little is known about the dynamics of these bacterial communities. Denaturing gradient gel electrophoresis (DGGE) was used to examine the bacterial microflora associated with the eusocial wasp Vespula germanica. DGGE profiles of larval guts revealed a variable microflora, suggesting that V. germanica is not dependent on a particular suite of mutualists. The variation in profiles was not related to season, nest size or macrohabitat. Sequences corresponding to Lactococcus, Lactobacillus, a novel Leuconostoc and two Rickettsiella grylli strains were obtained. DGGE proved to be a useful technique for characterizing the wasp microflora. Given the importance of microbial communities to invertebrates, there is much to be gained from the application of such techniques.