The Future of Schistosomiasis Control

Abstract

Tests with the Fontan R11, manufactured by Motan G.M.B.H. of West Germany, are described. The machine was tested as a mistblower using fluids at conventional discharge rates and with ULV restrictors.     

Transposon mutagenesis in Mycoplasma hyopneumoniae using a novel mariner-based system for generating random mutations

Mycoplasma hyopneumoniae is the cause of enzootic pneumonia in pigs, a chronic respiratory disease associated with significant economic losses to swine producers worldwide. The molecular pathogenesis of infection is poorly understood due to the lack of genetic tools to allow manipulation of the organism and more generally for the Mycoplasma genus. The objective of this study was to develop a system for generating random transposon insertion mutants in M. hyopneumoniae that could prove a powerful tool in enabling the pathogenesis of infection to be unraveled. A novel delivery vector was constructed containing a hyperactive C9 mutant of the Himar1 transposase along with a mini transposon containing the tetracycline resistance cassette, tetM. M. hyopneumoniae strain 232 was electroporated with the construct and tetM-expressing transformants selected on agar containing tetracycline. Individual transformants contained single transposon insertions that were stable upon serial passages in broth medium. The insertion sites of 44 individual transformants were determined and confirmed disruption of several M. hyopneumoniae genes. A large pool of over 10 000 mutants was generated that should allow saturation of the M. hyopneumoniae strain 232 genome. This is the first time that transposon mutagenesis has been demonstrated in this important pathogen and could be generally applied for other Mycoplasma species that are intractable to genetic manipulation. The ability to generate random mutant libraries is a powerful tool in the further study of the pathogenesis of this important swine pathogen.     

A mantle plume initiation model for the wrangellia flood basalt and other oceanic plateaus

The vast Wrangellia terrane of Alaska and British Columbia is an accreted oceanic plateau with Triassic strata that contain a 3- to 6-kilometers thick flood basalt, bounded above and below by marine sedimentary rocks. This enormous outpouring of basalt was preceded by rapid uplift and was followed by gradual subsidence of the plateau. The uplift and basalt eruptions occurred in less than approximately 5 million years, and were not accompanied by significant extension or rifting of the lithosphere. This sequence of events is predicted by a mantle plume initiation, or plume head, model that has recently been developed to explain continental flood volcanism. Evidence suggests that other large oceanic basalt plateaus, such as the Ontong-Java, Kerguelen, and Caribbean, were formed as the initial outbursts of the Louisville Ridge, Kerguelen, and Galapagos hot spots, respectively. Such events may play an important role in the creation and development of both oceanic and continental crust.     

Avian extinction and mammalian introductions on oceanic islands

The arrival of humans on oceanic islands has precipitated a wave of extinctions among the islands' native birds. Nevertheless, the magnitude of this extinction event varies markedly between avifaunas. We show that the probability that a bird species has been extirpated from each of 220 oceanic islands is positively correlated with the number of exotic predatory mammal species established on those islands after European colonization and that the effect of these predators is greater on island endemic species. In contrast, the proportions of currently threatened species are independent of the numbers of exotic mammalian predator species, suggesting that the principal threat to island birds has changed through time as species susceptible to exotic predators have been driven extinct.     

Detection of mutations in the 7A allele of wheat (Triticum aestivum) granule-bound starch synthase (Wx-7A) with a monoclonal antibody produced by targeted peptide immunisation

A peptide sequence unique for the granule-bound starch synthase (GBSS1) of hexaploid wheat (Triticum aestivum) was identified by sequence alignment of the three isoforms. Multiple antigenic peptides (MAP) of different length (16 and 20 AA) were synthesised against the selected sequence. The assessment of the immune response in mice against differently presented forms (resin-bound, free) and two types of adjuvants indicated that the free MAP with the longer peptide is more immunogenic. A 20AA MAP that elicited a strong immune response was used to produce a monoclonal antibody for the 7A isoform of GBSS 1. Epitope mapping of the selected Mab (F5-1F2) revealed that a 12mer partial sequence of the immunising peptide was specifically detected. Based on this Mab, a simple high throughput ELISA was developed that allows the quick identification of wheat lines carrying the 7A allele of GBSS 1 with minute amounts of sample.