Query: NC_005957:5203915 Bacillus thuringiensis serovar konkukian str. 97-27, complete
Lineage: Bacillus thuringiensis; Bacillus; Bacillaceae; Bacillales; Firmicutes; Bacteria
General Information: This organism was isolated from a case of severe human tissue necrosis which is unusual since human infections by this organism are rare. Produces insect toxinT his organism, also known as BT, is famous for the production of an insecticidal toxin. The bacterium was initially discovered as a pathogen of various insects and was first used as an insecticidal agent in the early part of this century. This organism, like many other Bacilli, is found in the soil, where it leads a saprophytic existence, but becomes an opportunistic pathogen of insects when ingested. The specific activity of the toxin towards insects and its lack of toxicity to animals has made this organism a useful biocontrol agent. The delta-endotoxin, which is produced during the sporulation part of the life cycle, causes midgut paralysis and disruption of feeding by the infected insect host. The delta-endotoxin, which is produced during the sporulation part of the life cycle, causes midgut paralysis and disruption of feeding by the infected insect host. The delta-endotoxin, which is produced during the sporulation part of the life cycle, causes midgut paralysis and disruption of feeding by the infected insect host. The presence of a parasporal crystal, which is outside the exosporium of the endospore, is indicative of production of the toxin, and serves as a marker for this species.Activation of the toxin typically requires a high pH environment such as the alkaline environments in insect midguts followed by proteolysis. Various toxin genes specific for a variety of insects have been studied, and many are now being used in genetically modified plants which have been engineered to produce the toxin themselves, eliminating the need to produce sufficient amounts of B. thuringiensis spores.
Subject: NC_005126:4824500 Photorhabdus luminescens subsp. laumondii TTO1, complete genome
Lineage: Photorhabdus luminescens; Photorhabdus; Enterobacteriaceae; Enterobacteriales; Proteobacteria; Bacteria
General Information: This strain was isolated on Trinidad and Tobago. It is a symbiont of the nematode Heterorhabditis bacteriophora. Bioluminescent bacterium. This organism is unusual in that it is symbiotic within one insect, and pathogenic in another, the only organism that is known to exhibit this dual phenotype. Enzymes are then released by the bacteria that result in rapid degradation of the insect body, allowing both bacteria and nematode to feed and reproduce. During this period Photorhabdus luminescens releases bacteriocidal products, including antibiotics and bacteriocins, that prevent infection of the larva by competitive microbes. The result is promotion of Photorhabdus luminescens-nematode interactions that result in continuation of the symbiotic relationship. In order to engage in a symbiotic relationship with the nematode and a pathogenic one with the insect larva, the bacterium encodes specific factors that encourage both. These include a large number of genes that code for secreted toxins and enzymes, as well as genes that encode products for the production of antibiotics and bacteriocins. Secretion of these products occurs by an array of systems including type I, type II, and type III secretion systems. The type III system is closely related to the Yersinia plasmid-encoded type III system. Genes that promote symbiotic relationships are also encoded on genomic islands on the chromosome including some that affect nematode development. Virulence genes appear to be active during exponential growth. Symbiotic genes appear to function during stationary phase (post-exponential) growth. The switch from one state to another is controlled. Photorhabdus luminescens is capable of giving off light, a complex process that requires the products of the lux operon.