To further investigate the recently described avian piroplasm, Babesia kiwiensis, blood samples were collected from 13 wild-caught and 8 zoo-captive brown kiwi (Apteryx mantelli) and screened for the presence of piroplasm DNA using a nested-polymerase chain reaction (PCR) targeting the 18S rRNA gene of most members of Piroplasmida. All captive birds gave a negative PCR result, while 12 wild-caught birds were PCR positive. The nearly full-length 18S rRNA gene for B. kiwiensis was sequenced. Upon phylogenetic analysis, it was found to belong to the babesid group of piroplasms and was ancestral, yet genetically similar, to the Babesia canis-related species. An insight into the current taxonomy of the avian piroplasms is also given. An Ixodes anatis tick collected from 1 of the North Island brown kiwi was also screened using PCR and was found to be positive for B. kiwiensis DNA.

ABSTRACTLittle is known of the prevalence ofCryptosporidiumandGiardiaparasites in sheep and the genotypes that they harbor, although potentially sheep may contribute significantly to contamination of watersheds. In the present study, conducted in Western Australia, a total of 1,647 sheep fecal samples were screened for the presence ofCryptosporidiumandGiardiaspp. using microscopy, and a subset (n= 500) were screened by PCR and genotyped. Analysis revealed that although both parasites were detected in a high proportion of samples by PCR (44% and 26% forGiardiaandCryptosporidiumspp., respectively), with the exception of oneCryptosporidium hominisisolate, the majority of isolates genotyped are not commonly found in humans. These results suggest that the public health risk of sheep-derivedCryptosporidiumandGiardiaspp. in catchment areas and effluent may be overestimated and warrant further investigation.

The Wilms' Tumour gene WT1 has important functions during development. Knock-out mice were shown to have defects in the urogenital system and to die at embryonic day E13.5, probably due to heart failure. Using a lacZ reporter gene inserted into a YAC construct, we demonstrate that WT1 is expressed in the early proepicardium, the epicardium and the subepicardial mesenchymal cells (SEMC). Lack of WT1 leads to severe defects in the epicardial layer and a concomitant absence of SEMCs, which explains the pericardial bleeding and subsequent embryonic death observed in Wt1 null embryos. We further show that a human-derived WT1 YAC construct is able to completely rescue heart defects, but only partially rescues defects in the urogenital system. Analysis of the observed hypoplastic kidneys demonstrate a continuous requirement for WT1 during nephrogenesis, in particular, in the formation of mature glomeruli. Finally, we show that the development of adrenal glands is also severely affected in partially rescued embryos. These data demonstrate a variety of new functions for WT1 and suggest a general requirement for this protein in the formation of organs derived from the intermediate mesoderm.

Occurring with a frequency of 1 in 10,000 live births, Wilms' tumor is one of the most common solid tumors of children. The genetic basis of this tumor is highly complex and several loci have been shown to be associated with tumor formation. Thus far, however, WT1 is the only gene that has been isolated and proven to carry mutations within Wilms' tumors. During the last few years, a wealth of experiments has been carried out to address the function of WT1 as a tumor suppressor and developmental regulator. This review focuses on studies addressing WT1 function; new approaches to understand WT1 function in vivo and present transgenic data in which WT1 was driven ectopically using a CMV promoter are discussed. Our results suggest that ubiquitous expression of WT1 is not compatible with embryonic development.

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To evaluate the number of sea-salt, sulfate, and carbonaceous particles associated with the fine and coarse mode aerosol in the marine boundary layer and from the marine/continental interface, the elemental composition of individual aerosol particles was determined with EM. Samples were collected from the Pacific marine boundary layer during a research cruise along 140 degrees W from the southern to northern hemisphere, and from a coastal station in NW Washington. Consistently, the most dominant aerosol types found were ammonium sulfate and acidic sulfate comprising 52 to 96% of the total number at a median diameter of 0.14 mu m. Sea-salt particles were 4 to 13% of the total number, with modes at 0.2 and 0.6 mu m. Carbonaceous particles, mostly as organic compounds, made up the remainder of the submicrometer aerosol at a few % to as much as 31% of the total number for continentally influenced periods. Silica-rich minerals and potassium and calcium salts were observed during such periods, representing a measurable, but small fraction of the total number. Sea-salt particles were 86 to 100% of the number of supermicrometer particles with a mass median diameter of 1.5 mu m. A less abundant, and variable fraction of mineral particles made up the remainder of the coarse aerosol number concentration identified primarily as aluminosilicates, mass median diameter of 0.9 mu m. Very little soot was observed in either the coarse or fine mode. Particle number concentrations were consistently low and airmass trajectories suggest the air originated over the open ocean for the majority of the sampling periods. Overall, normalized EM distributions agreed fairly well with in-situ measurements of the aerosol size distribution.

Wilms' Tumour I gene (WT1) is required for the correct development of the urogenital system. To examine its regulation and expression, we created several transgenic mouse lines containing a β-galactosidase reporter driven by the human WT1 promoter. A 5 kb promoter weakly recapitulated a subset of the endogenous Wt1 expression pattern. In contrast, 470 and 280 kb YAC transgenes reproduced the correct pattern with high activity and highlighted new expression sites. Wt1 is expressed in the septum transversum revealing how its mutation causes diaphragmatic defects. Wt1 expression in the limb demarcates a zone between chondrogenic and apoptotic domains. Finally, Wt1 is expressed in mesenchymal cells derived from the coelomic epithelium. Based upon these and further data we discuss a Wt1 role in epithelial↔mesenchymal transitions.