Midgut cells

Nardi J. B., Gilg Young A., Ujhelyi E., Tittiger C., Lehane M. J. and Blomquist G. J. (2002) Specialization of midgut cells for synthesis of male isoprenoid pheromone in two scolytid beetles, Dendroctonus jeffreyi and Ips pini. Tissue and Cell. 226, 221— 231. 

Specialization of midgut cells for synthesis of male isoprenoid pheromone components in two scolytid beetles, Dendroctonus jeffreyi and Ips pini. Tissue Cell. (in press). 

Unlike in dipterans, there is no ecdysteroid to complicate JH III action in adult bark beetles indeed, JH III appears to act alone in elevating HMG-R transcription in males. Furthermore, the clear, vigorous response by the mevalonate pathway in bark beetle midgut cells presents a simple metabolic focus, in contrast to the complicated developmental contexts studied in moths and flies. 

The bacterium Bacillus thuringiensis forms an internal crystal that contains a number of insecticidal protein toxins. When eaten by the insect, the crystal dissolves in the midgut, the toxin mixture is released, and the proteins are cleaved into active forms. The toxins bind specifically to midgut cells and assemble a pore that leads to disintegration of the cells, gut paralysis, and death. B. thuringiensis strains have toxins specific for caterpillars, beetles, or flies. They have little or no effect on mammals. 

Midgut cell membrane Bacillus thuringiensis Midgut-membrane disruption... 

Histological studies of infected larch sawfly larvae suggest that the damage to midgut cells and other tissues in the body involves parts of the cells that are known to be partially made up of phos-pholipides. 

Table 1. Concentration of cadmium (mean SE in (jtg/g dry weight) in the midgut cells and gonads of C. brunneus from five sites ...

Cadmium load in the midgut cells of grasshoppers from less polluted site (Tychy) raised proportionally to its concentration in the eaten grass, without significant differences between males and females (Tables 10 and 11). 

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