Detection of iron in tissues from slugs (deroceras reticulatum müller) after ingestion of iron chelates,by means of energy-filtering transmission electron microscopy (EFTEM)

Two iron chelates, one toxic (iron ‘butan’) and the other not (iron ‘octan’), were ingested by slugs (Deroceras reticulatum) at either a low (5 g kg⁻¹ diet) or a high (100 g kg⁻¹ diet) dose rate. In tissue sections of the digestive gland and body wall, iron was detected by energy-filtering transmission electron microscopy (EFTEM), using electron spectroscopical imaging (ESI) and electron energy-loss spectroscopy (EELS). The strongest signals for iron were obtained in secondary lysosomes of the resorptive cells in the digestive gland of slugs treated with a low dose of either compound, or with the high dose of iron ‘octan’. At the cell apices of these cells, in endocytotic vesicles and in apically located lysosomes, iron was detected only in slugs fed with either dose of iron ‘octan’. In slugs fed with the high dose of iron ‘butan’, iron could clearly be localised in the epithelial and mucus cells of the skin. The results are discussed with respect to differences in the toxicity of the two iron chelates. © 1999 Society of Chemical Industry     

The genome sequence of Drosophila melanogaster

The fly Drosophila melanogaster is one of the most intensively studied organisms in biology and serves as a model system for the investigation of many developmental and cellular processes common to higher eukaryotes, including humans. We have determined the nucleotide sequence of nearly all of the approximately 120-megabase euchromatic portion of the Drosophila genome using a whole-genome shotgun sequencing strategy supported by extensive clone-based sequence and a high-quality bacterial artificial chromosome physical map. Efforts are under way to close the remaining gaps; however, the sequence is of sufficient accuracy and contiguity to be declared substantially complete and to support an initial analysis of genome structure and preliminary gene annotation and interpretation. The genome encodes approximately 13,600 genes, somewhat fewer than the smaller Caenorhabditis elegans genome, but with comparable functional diversity.     

Phycomycosis in a dog.

Chronic vomiting in a 2-year-old dog was suspected to be due to a neoplasm of the stomach wall. During exploratory laparotomy, a lymph node from the pyloric area was examined microscopically. Inasmuch as neoplastic cells or evidence of metastasis were not found, all visibly involved tissue was removed surgically. A diagnosis of phycomycosis was then established by histologic evaluation of the tissue removed. It was concluded that diagnosis of this disease is important inasmuch as it may be treated successfully, in contrast to the situation with malignant neoplastic conditions, which it grossly resembles.     

Seroprevalence of Neospora caninum in beef cattle in northern Alberta

Blood samples were collected from 1806 pregnancy-tested cows from 174 herds at a northern Alberta auction mart in the fall of 1998. One hundred sixty-two (9.0%) of these samples were positive for antibodies to N. caninum. Thirty-five of 260 samples (13.5%) collected from the same region in the 1980s were also serologically positive for N. caninum.