Evidence for the persistence of an active endogenous retrovirus (ERVE) in humans

Transposable elements (TEs) account for nearly half (44 %) of the human genome. However, their overall activity has been steadily declining over the past 35–50 million years, so that <0.05 % of TEs are presumably still “alive” (potentially transposable) in human populations. All the active elements are retrotransposons, either autonomous (LINE-1 and possibly the endogenous retrovirus ERVK), or non-autonomous (Alu and SVA, whose transposition is dependent on the LINE-1 enzymatic machinery). Here we show that a lineage of the endogenous retrovirus ERVE was recently engaged in ectopic recombination events and may have at least one potentially fully functional representative, initially reported as a novel retrovirus isolated from blood cells of a Chinese patient with chronic myeloid leukemia, which bears signals of positive selection on its envelope region. Altogether, there is strong evidence that ERVE should be included in the short list of potentially active TEs, and we give clues on how to identify human specific insertions of this element that are likely to be segregating in some of our populations.     

Clades of γ-glutamyltransferases (GGTs) in the ascomycota and heterologous expression of Colletotrichum graminicola CgGGT1, a member of the pezizomycotina-only GGT clade

Gamma-glutamyltransferase (GGT, EC 2.3.2.2) cleaves the γ-glutamyl linkage in glutathione (GSH). Ascomycetes in either the Saccharomycotina or the Taphrinomycotina have one to three GGTs, whereas members of the Pezizomycotina have two to four GGTs. A Bayesian analysis indicates there are three well-supported main clades of GGTs in the Ascomycota. 1) A Saccharomycotina and a Taphrinomycotina-specific GGT sub-clade form a yeast main clade. This clade has the three relatively well-characterized fungal GGTs: (Saccharomyces cerevisiae CIS2 and Schizosaccharomyces pombe Ggt1 and Ggt2) and most of its members have all 14 of the highly conserved and critical amino acids that are found in GGTs in the other kingdoms. 2) In contrast, a main clade (GGT3) differs in 11 of the 14 highly conserved amino acids that are found in GGTs in the other kingdoms. All of the 44 Pezizomycotina analyzed have either one or two GGT3s. 3) There is a Pezizomycotina-only GGT clade that has two well-supported sub-clades (GGT1 and GGT2); this clade differs in only two of the 14 highly conserved amino acids found in GGTs in the other kingdoms. Because the Pezizomycotina GGTs differ in apparently critical amino acids from the cross-kingdom consensus, a putative GGT from Colletotrichum graminicola, a member of the Pezizomycotina, was cloned and the protein product was expressed as a secreted protein in Pichia pastoris. A GGT enzyme assay of the P. pastoris supernatant showed that the recombinant protein was active, thereby demonstrating that CgGGT1 is a bona fide GGT.     

Protoplast fusion of Lactobacillus fermentum

Tetracycline-resistant (Tetr) erythromycin-resistant (Eryr) fusants of Lactobacillus fermentum 604 carrying a 10-megadalton Tetr plasmid and L. fermentum 605 carrying a 38-megadalton Eryr plasmid were obtained by means of polyethylene glycol-induced protoplast fusion.     

Comparison of a Chemically Mediated and an Immunologically Mediated Demyelinating Lesion Model

The production of two animal models for the central nervous system degenerative condition multiple sclerosis is described in detail. The first is a chemically mediated noninflammatory demyelinating lesion of the brain stem induced by the injection of a trypanocidal DNA binding dye, ethidium bromide, into the cerebellomedullary cistern. The injection does not involve any physical damage to the blood–brain barrier or the CSF–brain barrier and is simple to perform. The second lesion model is an immunologically mediated demyelinating condition involving the injection of a T-cell line specific for myelin basic protein, followed by injection of a monoclonal antibody against the myelin surface protein, myelin/oligodendrocyte glycoprotein. We describe the production of the antigen-specific T-cell line in detail. This model is characterized by widespread inflammatory infiltrates accompanied by areas of demyelination. Both of these models are produced in the Lewis rat, allowing the direct comparison of mechanisms involved in demyelination and repair in the presence or absence of invading inflammatory cells. Despite the very different etiologies of the two lesion models, they are both acute and result in efficient remyelination.     

Two new Neotropical species of Perithreticus Vaillant 1973 (Diptera: Psychodidae,Psychodinae)

The genus Perithreticus is recorded for the first time from Central America and the Caribbean. Two new species are described and figured: P. arboscandens Kvifte & Andersen, n. sp. from Zurquí, San José Province, Costa Rica and P. guantanamera Kvifte & Andersen, n. sp. from Alexander von Humboldt National Park, Guantánamo Province, Cuba. The generic diagnosis is emended to accommodate the newly described species, and a key to the males of the Perithreticus species of the world is presented.     

Proffered Papers 10.30–11.15 Monday 15 September 2003

Introduction  Colposcopy Quality Standards state that more than 85% of excisional biopsies should show CIN 1 or worse. Data from the National KC65 reports show a large difference between units (50% to 100%). This study investigates the reasons for failure to meet the standard.
Methods  A review of 1158 consecutive new and 1043 follow-up colposcopy examinations from a colposcopy database in East Somerset. Patients were treated at the time of initial examination if there was a clinically significant lesion, or at follow-up depending on the results of investigations.
Results  Only 59% of excisional biopsies showed CIN 1 or worse. The possible reasons for failure to meet the standard were explored. Possible explanations explored are erroneous colposcopy, false negative histology, and false positive cytology. The cytology–histology correlation was compared between excisional and directed biopsies, and between the two local cytology screening departments.
Conclusions  The collection of meaningful national data has more to do with careful definition than clinical practice or data collection.