Biomedical subjects

G Shearer

Publications and source records attributed to G Shearer.

75 records · Page 5Linked to original sources

PubMedDate not supplied

Effects of extraction and spiking procedures on the determination of incurred residues of oxytetracycline in cattle kidney.

The effects of different extraction and spiking procedures on the determination of incurred oxytetracycline residues in animal tissues have been investigated. The extraction procedures investigated--direct aqueous or organic solvent extraction, enzymic digestion or sonication--all gave similar results for incurred oxytetracycline concentration in cattle kidney after correction for spike recovery. There was therefore no evidence for binding or conjugation of oxytetracycline in this tissue. Highest recovery from spiked tissue was obtained using ethyl acetate as extractant. The effects of spiking procedure (spike contact time, spike solvent and tissue state) on recovery from spiked cattle kidney were also small, indicating that added oxytetracycline spike does not interact with the tissue.

Animals↗

PubMedDate not supplied

Isolation and characterization of a calmodulin-encoding cDNA from the pathogenic fungus Histoplasma capsulatum.

We describe in this paper the isolation and complete sequence of a calmodulin (CaM) encoding cDNA from the dimorphic pathogenic fungus Histoplasma capsulatum (GenBank accession U12505). The deduced amino acid sequence was identical to the CaM of Aspergillus nidulans and had only one amino acid difference from the CaM of Neurospora crassa. Saccharomyces cerevisiae CaM, however, has only about 60% amino acid identity compared with H. capsulatum. These data further support the close relationship of Histoplasma to the filamentous ascomycetes. Histoplasma CaM was expressed as a single major transcript of approximately 1200 nt. in both the yeast and mould growth forms. CaM mRNA levels were approximately two-fold greater in the yeast than in the mould form of the organism. Southern blot analysis indicated that the H. capsulatum CaM gene is present in a single copy.

Amino Acid Sequence↗

PubMedDate not supplied

Cloning and analysis of an actin-encoding cDNA from the dimorphic pathogenic fungus Histoplasma capsulatum.

We have cloned an actin-encoding cDNA from the dimorphic fungus Histoplasma capsulatum, an important pathogen of humans. The predicted amino acid sequence as well as the general codon pattern of Histoplasma actin revealed the highest degree of similarity to the actin of the filamentous ascomycete Aspergillus nidulans. Southern blot analysis determined that actin was encoded by a single copy in the Histoplasma genome. Northern blot analysis showed a single 1700 nt transcript in yeast and mould cells as well as in cells undergoing the temperature induced mould-to-yeast conversion. Actin mRNA levels normalized to 18 S rRNA were found to be equivalent in all the stages examined, except for a sharp four-fold transient decrease 4 h into the mould-to-yeast conversion. These data suggest that actin mRNA would not be a suitable internal marker for expression studies during Histoplasma mould-to-yeast morphogenesis.

Actins↗