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Lorna Macfarlane

Publications and source records attributed to Lorna Macfarlane.

4 recordsLinked to original sources
PubMed2006

New insights into the phylogeny of Entamoeba species provided by analysis of four new small-subunit rRNA genes.

Sequences of small-subunit rRNA genes have been obtained for four new isolates of Entamoeba. Phylogenetic analyses give new insights into the evolution of these organisms. A novel Entamoeba from pigs in Vietnam that produces uninucleate cysts proved to be unrelated to other uninucleated cyst-producing species. Revival of the name Entamoeba suis for this organism is proposed. Instead of being related to Entamoeba polecki, it shares a recent common ancestor with the non-encysting Entamoeba gingivalis in a lineage that is basal to the tetranucleate cyst-producing clade. This suggests that species producing cysts with four nuclei are descended from an ancestor that produced cysts with a single nucleus. An Entamoeba from a horse was isolated in culture. No cysts were observed in the original stool sample but the sequence is placed unequivocally within the clade of tetranucleate cyst-producing species with no other sequences being specifically related. Revival of the name Entamoeba equi for this organism is proposed. The Entamoeba ecuadoriensis sequence was found to be the most closely related to Entamoeba histolytica and Entamoeba dispar, as predicted, despite the organism having been an environmental isolate originally assigned to Entamoeba moshkovskii. Finally, a partial E. polecki gene sequence from a pig proved to be virtually identical to that of Entamoeba struthionis from an ostrich, suggesting that the latter name is a synonym.

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PubMed2005

Non-travel-associated hepatitis E in England and Wales: demographic, clinical, and molecular epidemiological characteristics.

Between 1996 and 2003, 186 cases of hepatitis E were serologically diagnosed. Of these, 17 (9%) were not associated with recent travel abroad. Patients were >55 years old (range, 56-82 years old) and tended to be male (76%). Two patients presented with fulminant hepatitis. A total of 129 (69%) cases were associated with recent travel to countries where hepatitis E virus (HEV) is hyperendemic. Compared with patients with travel-associated disease, patients with non-travel-associated disease were more likely to be older, living in coastal or estuarine areas, not of South Asian ethnicity, and infected by genotype 3 strains of HEV. The genotype 3 subgenomic nucleotide sequences were unique and closely related to those from British pigs. Patients infected by HEV indigenous to England and Wales tended to belong to a distinct demographic group, there were multiple sources of infection, and pigs might have been a viral reservoir.

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PubMedDate not supplied

Internal transcribed spacer dimorphism and diversity in Dientamoeba fragilis.

The internal transcribed spacer (ITS) region of the ribosomal RNA operon is frequently used for detecting sequence variation among closely related species as it is usually homogeneous within strains but evolves more rapidly than ribosomal RNA coding regions. We have studied this region in both genotypes of the human intestinal parasite Dientamoeba fragilis. In contrast to most organisms, we have identified extensive variation between copies of the sequence within the same strain. The ITS occurs in 2 major forms in each genotype but additional heterogeneity is also present within each form. The significance of this finding is unclear, but the only precedent for such variation is in the Apicomplexa, which have multiple dispersed ribosomal RNA operons in contrast to the tandem arrays found in most other eukaryotes.

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