Phylogeographic diversity and mosaicism of the integrative and conjugative elements.

Background: The genome of the gastric pathogen is characterised by considerable variation of both gene sequence and content, much of which is contained within three large genomic islands comprising the pathogenicity island (PAI) and two mobile integrative and conjugative elements (ICEs) termed and . All three islands are implicated as virulence factors, although whereas the PAI is well characterised, understanding of how the elements influence interactions with different human hosts is significantly confounded by limited definition of their distribution, diversity and structural representation in the global population.

Results: To gain a global perspective of ICE population dynamics we established a bioinformatics workflow to extract and precisely define the full pan-gene content contained within a global collection of 221 draft and complete genome sequences.

A role for the tfs3 ICE-encoded type IV secretion system in pro-inflammatory signalling by the Helicobacter pylori Ser/Thr kinase, CtkA.

Two distinct type IV secretion systems (T4SSs) can be identified in certain Helicobacter pylori strains, encoded on mobile genetic elements termed tfs3 and tfs4. Although their function remains unknown, both have been implicated in clinical outcomes of H. pylori infection.

A role for the vacuolating cytotoxin, VacA, in colonization and Helicobacter pylori-induced metaplasia in the stomach.

Carriage of Helicobacter pylori strains producing more active (s1/i1) forms of VacA is strongly associated with gastric adenocarcinoma. To our knowledge, we are the first to determine effects of different polymorphic forms of VacA on inflammation and metaplasia in the mouse stomach. Bacteria producing the less active s2/i2 form of VacA colonized mice more efficiently than mutants null for VacA or producing more active forms of it, providing the first evidence of a positive role for the minimally active s2/i2 toxin.

Epigenetic reprogramming in the porcine germ line.

Background: Epigenetic reprogramming is critical for genome regulation during germ line development. Genome-wide demethylation in mouse primordial germ cells (PGC) is a unique reprogramming event essential for erasing epigenetic memory and preventing the transmission of epimutations to the next generation. In addition to DNA demethylation, PGC are subject to a major reprogramming of histone marks, and many of these changes are concurrent with a cell cycle arrest in the G2 phase.

Pig epiblast stem cells depend on activin/nodal signaling for pluripotency and self-renewal.

Activin/Nodal signaling is required for maintaining pluripotency and self-renewal of mouse epiblast stem cells and human embryonic stem cells (hESC). In this study, we investigated whether this signaling mechanism is also operative in cultured epiblasts derived from Days 10.5-12 pig embryos.