PCR-based analysis of spores isolated from smears by laser pressure catapult microdissection confirms genetic identity of spore morphotypes of the microsporidian Thelohania solenopsae

Chromosomal localization of a proinsulin transgene in Japanese quail by laser pressure catapulting

Transgenic avian bioreactors produce therapeutic recombinant proteins in egg white. To date, however, methods for transgenic modification of the avian genome or determining transgenic status of individual birds are scarce. The dual, but interrelated, goals of this research were to: (1) develop a method of detecting stable DNA insertion into Japanese quail; and (2) provide a method for gene location on avian chromosomes. We created Teflon-coated coverslip slides to facilitate laser pressure catapulting of avian chromosomes for DNA amplification and nucleotide sequencing. Transgenic G2 Japanese quail, containing germline incorporation of proinsulin, were identified by isolation of chromosomes using laser microdissection and laser pressure catapulting. Subsequent amplification of each chromosome identified 2-5 chromosomes with the proinsulin transgene inserted. Nucleotide sequencing of each chromosomal insertion was identical to the proinsulin portion of the original vector. By applying laser pressure catapulting and PCR of individual chromosomes, we were able to determine that the transgene correctly inserted into avian chromosomes and that the majority of the insertions occurred within microchromosomes. Because many potential therapeutic transgenes have similar or nearly identical nucleotide sequence to the host's native gene, laser microdissection and subsequent analysis may be required for detailed documentation of transgene expression before proceeding with transgenic protein production.

Effect of mono- and polygyne social forms on transmission and spread of a microsporidium in fire ant populations

Thelohania solenopsae is a pathogen of the red imported fire ant, Solenopsis invicta, which debilitates queens and eventually causes the demise of colonies. Reductions of infected field populations signify its potential usefulness as a biological control agent. Thelohania solenopsae can be transmitted by introducing infected brood into a colony. The social forms of the fire ant, that is, monogyny (single queen per colony) or polygyny (multiple queens per colony), are associated with different behaviors, such as territoriality, that affect the degree of intercolony brood transfer. T. solenopsae was found exclusively in polygyne colonies in Florida. Non-synchronous infections of queens and transovarial transmission favor the persistence and probability of detecting infections in polygynous colonies. However, queens or alates with the monogyne genotype can be infected, and infections in monogyne field colonies have been reported from Louisiana and Argentina. Limited independent colony-founding capability and shorter dispersal of alate queens with the polygyne genotype relative to monogyne alates may facilitate the maintenance of infections in local polygynous populations. Demise of infected monogyne colonies can be twice as fast as in polygyne colonies and favors the pathogen's persistence in polygyne fire ant populations. The social form of the fire ant reflects different physiological and behavioral aspects of the queen and colony that will impact T. solenopsae spread and ultimate usefulness for biological control.

Laser pressure catapulting followed by B actin gene identification in Japanese quail macrochromosomes and microchromosomes using teflon-coated coverslip slides

Laser microdissection of individual mammalian chromosomes (> 2 microm) has been achieved though the use of a microscope slide coated with a polyethylene naphthalate (PEN) membrane. Although these slides have proved sufficient for larger chromosomes, they are insufficient for small chromosomes (< 1 microm). We have developed a new type of slide which allows laser microdissection of single Japanese quail microchromosomes (0.5 microm) and macrochromosomes (3-4 microm). To test the usefulness of these slides, a Japanese quail single nucleus, a macrochromosome, and a microchromosome were collected with Laser pressure catapulting, the B-actin gene was PCR amplified, and sequenced. The resulting PCR product was confirmed by nucleotide sequencing to be B-actin. These newly developed slides were shown to facilitate the laser microdissection of both Japanese quail macrochromosomes and microchromosomes.