Recent non‐native invertebrate plant pest establishments in Great Britain: origins,pathways, and trends

1 An appraisal of non‐native invertebrate plant pest establishments in Great Britain, between 1970 and 2004, was carried out to improve our understanding of current invasion processes by non‐native plant pests, and to assist national strategies in managing the risks they pose. 2 A total of 164 establishments, comprising 50 natural colonists and 114 human‐assisted introductions, were recorded across 13 major taxonomic groups. 3 The mean rate of establishment was 22.1 species per 5‐year period: 19.1 and 3.0 species outside and inside protected cultivation, respectively. Despite the continuing rapid growth in international trade and a general perception that rates of pest invasions are accelerating, no significant temporal trends in the rate of establishments in Great Britain were detected, either for natural colonists or human‐assisted introductions, or for pests of plants grown indoors or outside. 4 The plant trade, particularly in ornamental plants, accounted for nearly 90% of human‐assisted introductions; apiculture, biological control, timber imports, transport stowaways and intentional releases each contributed less than 5%. Only eight (4.9%) of the establishments could be considered as having no direct potential economic impact because all other species have been recorded as feeding on cultivated plants. A greater proportion of establishments by both natural colonists and human‐assisted introductions occurred on non‐native, woody plants. 5 The present study confirms previous work in other European countries that highlight the predominant role of the ornamental plant trade in introducing new plant pests to the European continent, mainly from Asia and North America.     

The identity,distribution, and impacts of non-native apple snails in the continental United States

Background  

Since the mid 1990s populations of non-native apple snails (Ampullariidae) have been discovered with increasing frequency in the continental United States. Given the dramatic effects that introduced apple snails have had on both natural habitats and agricultural areas in Southeast Asia, their introduction to the mainland U.S. is cause for concern. We combine phylogenetic analyses of mtDNA sequences with examination of introduced populations and museum collections to clarify the identities, introduced distributions, geographical origins, and introduction histories of apple snails.     

A comparative location database (CompLDB): map integration within and between species

We have adapted the Location Database (LDB) map-integration strategy of Morton et al. [Ann Hum Genet 56:223–232] (1992) as above to create an integrated map for each of several species for which fully annotated genome sequences are not yet available (sheep, cattle, pig, wallaby), using all types of partial maps for that species, including cytogenetic, linkage, somatic-cell hybrid, and radiation hybrid maps. An integrated map provides not only predictions of the kilobase location of every locus, but also predicts locations (in cM) and cytogenetic band locations for every locus. In this way a comprehensive linkage map and a comprehensive cytogenetic map are created, including all loci, irrespective of whether they have ever been linkage mapped or physically mapped, respectively. High-resolution physical maps from annotated sequenced species have also been placed alongside the integrated maps. This has created a powerful tool for comparative genomics. The LDB map-integration strategy has been extended to make use of zoo-FISH comparative information. It has also been extended to enable the creation of a “virtual” map for each species not yet sequenced by using mapping data from fully sequenced species. All of the partial maps, together with the integrated map, for each species have been placed in a database called Comparative Location Database (CompLDB), which is available for querying, browsing, or download in tabular form at . Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Rearrangement of a stable RNA secondary structure during VS ribozyme catalysis

The Neurospora VS ribozyme recognizes and cleaves a substrate RNA that contains a GC-rich stem loop. In contrast to most RNA secondary structures that are stable during tertiary or quaternary folding, this substrate undergoes extensive ribozyme-induced rearrangement in the presence of magnesium in which the base pairings of at least seven of the ten nucleotides in the stem are changed. This conformational switch is essential for catalytic activity with the wild-type substrate and creates a metal-binding secondary structure motif near the cleavage site. Base pair rearrangement is accompanied by bulging a cytosine from the middle of the stem, indicating that ribozymes may perform base flipping, an activity previously observed only with protein enzymes that modify DNA.     

Stem cell marker TRA-1-60 is expressed in foetal and adult kidney and upregulated in tubulo-interstitial disease

The kidney has an intrinsic ability to repair itself when injured. Epithelial cells of distal tubules may participate in regeneration. Stem cell marker, TRA-1-60 is linked to pluripotency in human embryonic stem cells and is lost upon differentiation. TRA-1-60 expression was mapped and quantified in serial sections of human foetal, adult and diseased kidneys. In 8- to 10-week human foetal kidney, the epitope was abundantly expressed on ureteric bud and structures derived therefrom including collecting duct epithelium. In adult kidney inner medulla/papilla, comparisons with reactivity to epithelial membrane antigen, aquaporin-2 and Tamm–Horsfall protein, confirmed extensive expression of TRA-1-60 in cells lining collecting ducts and thin limb of the loop of Henle, which may be significant since the papillae were proposed to harbour slow cycling cells involved in kidney homeostasis and repair. In the outer medulla and cortex there was rare, sporadic expression in tubular cells of the collecting ducts and nephron, with positive cells confined to the thin limb and thick ascending limb and distal convoluted tubules. Remarkably, in cortex displaying tubulo-interstitial injury, there was a dramatic increase in number of TRA-1-60 expressing individual cells and in small groups of cells in distal tubules. Dual staining showed that TRA-1-60 positive cells co-expressed Pax-2 and Ki-67, markers of tubular regeneration. Given the localization in foetal kidney and the distribution patterns in adults, it is tempting to speculate that TRA-1-60 may identify a population of cells contributing to repair of distal tubules in adult kidney.