Glucose is a universal phagostimulant in many animal species, including the cockroach Blattella germanica. However, some natural populations of B. germanica have been found that are behaviorally deterred from eating glucose. In dose-response studies, glucose was a powerful phagostimulant for wild-type cockroaches, but it strongly deterred feeding in a glucose-averse strain. Both strains, howeve...

The corpora allata (CA) of ovariectomized adult Blattella germanica females exhibited delayed but high rates of juvenile hormone biosynthesis in vitro. Using the onset of sexual receptivity as a probe of the degree of CA activation in females, we demonstrated at least one cycle of CA activity in the experimentally synchronized ovariectomized females. Following their activation, the CA exhibited...

BACKGROUND Insect eggshells must combine protection for the yolk and embryo with provisions for respiration and for the entry of sperm, which are ensured by aeropyles and micropyles, respectively. Insects which oviposit the eggs in an egg-case have a double problem of respiration as gas exchange then involves two barriers. An example of this situation is found in the cockroach Blattella germani...

Diflubenzuron (DIMILIN) is a powerful insecticidal chemical which has been known for many years to inhibit chitin synthesis in vivo in insects and related arthropod species. However, its action mechanism has remained unresolved partly because of its inaction on any of the enzymes involved in chitin synthesis in vitro. Based on our previous work (Diflubenzuron affects gamma-thioGTP stimulated Ca...

We used RNA interference (RNAi) to silence the expression of a gene encoding Bla g 1, a human allergen produced by the German cockroach, Blattella germanica L., to study its function in cockroach physiology. Females injected with 1 microg of double-stranded RNA contained 64% less Bla g 1 protein and Bla g 1 mRNA abundance was reduced by 91.4% compared to sham-injected females. Bla g 1 knockdown...

A new Blattella germanica densovirus (BgDNV, Parvoviridae: Densovirinae, Densovirus) was found. Virus DNA and cockroach tissues infected with BgDNV were examined by electron microscopy. Virus particles about 20 nm in diameter were observed both in the nucleus and in the cytoplasm of infected cells. Virus DNA proved to be a linear molecule sized about 1.2 microns. The complete BgDNV genome was s...

Allatostatins of the YXFGLamide group were discovered in cockroaches through their capacity to inhibit juvenile hormone biosynthesis. Here, we assess the occurrence of preproallatostatin (preproAST) mRNA in the brain and midgut of adult females of the cockroach Blattella germanica, and estimate brain and midgut preproAST mRNA levels during the first reproductive cycle. Reverse transcription pol...

The German cockroach, Blattella germanica (L.), produces several potent protein aeroallergens, including Bla g 4, a approximately 20 kDa lipocalin. RT-PCR, Northern analyses and in situ hybridization showed that Bla g 4 is expressed only in the adult male reproductive system. Western blotting and ELISA with rBla g 4 antiserum detected immunoreactivity in the utricles and the conglobate gland, b...

Strains of German cockroach, Blattella germanica (L.) were tested for resistance to three insecticides using the time-mortality response technique in comparison with known susceptible strains. Dursban-R and Macy strains indicated high levels of resistance to chlorpyrifos and moderate resistance to propoxur and cypermethrin. The hydrolytic activity of esterase enzymes was determined with a model...