A Disease of Grasshoppers Caused by the Bacterium Pseudomonas Aeruginosa (Schroeter) Migula

Abstract

Pse2ldonzonas acrzlginosa is the chief cause of disease in laboratory cultures of grasshoppers. A large number of strains of the bacterium from different localities fell into five types on the basis of reactions with bacteriophages. The five types and their strains were qualitatively similar to one another in morphology, cultural characteristics, and diagnostic biochemical reactions and to a narned culture of P. aeruginosa from the American Type Culture Collection, and their characteristicsagreed with those listed by most authors in the literature a s diagnostic of the species. The strainsand types showed some quantitative differences in production of pyocyanin, development of iridescence, and degree of haemolysis of blood and of hydrolysis of casein. The symptoms of infection and the loss from tnortality are described. The factors influencing the spread of the infection are discussed and methods of suppression of the disease are recommended. The disease originates from a small number of bacteria intimately associated with a very low percentage of grasshopper eggs collected in the field. Nymphs emerging from these eggs die shortly after emergence and contaminate the food supply. Grasshoppers are normally infected by ingesting food contaminated by the bacteria but the bacteria do not multiply in the gut and most of them are rapidly lcilled or eliminated. The bacteria are not actively invasive, but when a small number gain access to the haemocoel they increase in numbers to about 1 X 10"er insect. Shortly thereafter the host dies frorn the metabolic activities of the parasites, most probably as a result of protein digestion by the strong proteolytic enzymes of the bacterium. There is no evidence that the bacteria produce a specific toxin, and grasshoppers are more resistant to the poisonous action of pyocyanin than are mice.'Manuscript

The first study on the bacterial flora of the european spruce bark beetle, Dendroctonus micans (Coleoptera: Scolytidae)

“…In previous studies, it was reported that P. putida could infect Euproctis chrysorrhoea (Steinhaus, 1963) and Mamestra brassicae (Lepidoptera: Noctuidae) (Ivanov & Gukasjan, 1966). Despite the fact that a number of Pseudomonas species are important insect pathogens, i.e., P. aeruginosa (Bucher & Stephens, 1957;Osborn et al, 2002), P. fluorescens (Krieg, 1961;Lipa & Wiland, 1972;Bucher, 1981;Sezen & Demirbag, 1999, Yaman et al, 1999 and P. chlororaphis (Ivanov & Gukasjan, 1966;Bucher, 1981;Yaman et al, 2002b), P. putida appears insignificant as an insect pathogen (Bucher, 1981;Schneider & Dorn, 2001).…”

QscR, a modulator of quorum-sensing signal synthesis and virulence in Pseudomonas aeruginosa

“…To test this, we used an insect model for P. aeruginosa pathogenesis. We tested the role of QscR in virulence by feeding the mutant and parent to the fruit fly D. melanogaster; a particularly convenient model host among the various insects in which P. aeruginosa causes disease (21)(22)(23). We fed fruit flies with P. aeruginosa cells suspended in a sucrose solution (see Materials and Methods) and monitored the flies for 2 weeks.…”

Pseudomonas aeruginosa PAO1 Kills Caenorhabditis elegans by Cyanide Poisoning

“…This compound thus could contribute profoundly to the broad pathogenic host range of P. aeruginosa (5,9,36,40,45). It is thought that cyanide inhibition of fungal growth helps account for the suppression of several plant root and leaf fungal diseases (30,68).…”

“…A model for nematode killing based on inhibition of mitochondrial cytochrome oxidase is presented. The action of cyanide helps account for the unusually broad host range of virulence of P. aeruginosa and may contribute to the pathogenesis in opportunistic human infections due to the bacterium.Pseudomonas aeruginosa is a ubiquitous gram-negative bacterium that is virulent towards a wide range of organisms, including bacteria, plants, nematodes, insects, and mammals (5,9,17,19,35,36,41,48,49,62). In humans, P. aeruginosa chronically infects the lungs of most cystic fibrosis patients, causes serious infections of burn wounds and eye lesions, and causes systemic infections of immunocompromised individuals (21,29,33,39).…”