Novel strategies for assessing and managing the risks posed by invasive alien species to global crop production and biodiversity

International actions to combat the threat posed by invasive alien species (IAS) to crops and biodiversity have intensified in recent years. The formulation of 15 guiding principles on IAS by the Convention on Biological Diversity (CBD) stimulated the International Plant Protection Convention (IPPC) to review its role in protecting biodiversity. IPPC standards now demonstrate clearly that the risks posed by any organism that is directly or indirectly injurious to cultivated or uncultivated plants can be assessed and managed under the IPPC. Since the IPPC, unlike the CBD, constitutes an international legal instrument recognised by the World Trade Organization, greater protection from the introduction of IAS is now available. However, phytosanitary measures can only be enacted if they can be justified by risk analysis and we outline some novel strategies to improve the assessment and management of the risks posed by IAS, highlighting some of the key challenges which remain.     

Two new rhabdocoel turbellarians, Umagilla pacifica sp.n. and U. karlingi sp.n. (Umagillidae), endosymbiotic with holothurians (Echinodermata) from the Great Barrier Reef; and a discussion of sclerotic structures in the female system of the Umagillidae

Umagilla pacifica sp.n. and U. karlingi sp.n. are described. A revised definition of the genus Umagilla Wahl, 1909 is given and Notothrix Hickman, 1955 is reduced to a synonym of Umagilla . The nature of the hard or sclerotic structures associated with the female system, especially the bursa, of umagillids is discussed and compared to similar structures in other turbellarians. Syndesmis evelinae Marcus, 1968, S. glandulosa Hyman, 1960, S. compacta Komschlies & Vande Vusse, 1980, S. mamillata Komschlies & Vande Vusse, 1980 and s. alcalai Komschlies & Vande Vusse, 1980 are all transferred to Syndisyrinx .     

pathmatrix: a geographical information system tool to compute effective distances among samples

pathmatrix is a tool used to compute matrices of effective geographical distances among samples using a least‐cost path algorithm. This program is dedicated to the study of the role of the environment on the spatial genetic structure of populations. Punctual locations (e.g. individuals) or zones encompassing sample data points (e.g. demes) are used in conjunction with a species‐specific friction map representing the cost of movement through the landscape. Matrices of effective distances can then be exported to population genetic software to test, for example, for isolation by distance. pathmatrix is an extension to the geographical information system (GIS) software arcview 3.x.     

Nemerteans of the Great Barrier Reef 6. Enopla Hoplonemertea (Polystilifera: Reptantia)

Two new genera and species of reptantic polystiliferous hoplonemerteans from the Great Barrier Reef province of Australia are described and illustrated. Urichonemertes pilorhynchus gen. et sp. nov. and Xenonemertes rhamphocephalus gen. et sp. nov. are both placed in the family Drepanophoridae (Polystilifera: Eureptantia: Aequifurcata).     

Failure of Neuraminidase to unmask Histocompatibility Antigens on Trophoblast

DURING outbred pregnancy the mother is exposed to genetically foreign tissue because the offspring inherits transplantation antigens from the father. The survival of the foetus is ensured by the intervention of the trophoblast which does not express transplantation antigens between mother and foetus: mouse trophoblast is not rejected even when transplanted into immune recipients^1,3. The mechanism of this failure to express histocompatibility antigens is not understood^1–4, but Kirby et al. have suggested that the extracellular fibrinoid surrounding trophoblast cells is involved^5,6. Currie has suggested that the thick sialomucinous glycocalyx of the trophoblast cell might “mask” the histocompatibility antigens on the trophoblast^7,8 and has demonstrated that neuraminidase unmasked these antigens⁸. Our experiments, however, show that trophoblast incubated with neuraminidase cannot sensitize allogeneic mice to donor histocompatibility antigens. Furthermore, pretreatment of trophoblastic implants with neuraminidase did not interfere with their proliferation and growth in highly immune allogeneic recipients.     

Polynucleotide Ligase and φX174 Single Strand Synthesis

A DNA ligase mutant of E. coli when infected with φX174 produces linear single strands which appear in an intracellular pool and in phage particles. The linear single strands, which are infectious in a spheroplast assay, seem to be a normal intermediate in progeny DNA synthesis.     

A phylogenetic analysis of subtribe Pleurothallidinae (Orchidaceae)

A cladistic analysis of subtribe, Pleurothallidinae (Orchidaceae) is based on 45 anatomical/ morphological characters. The ingroup members comprise 24 genera; the large genus Pleurothallis consists of two subgenera and ten species complexes. Three taxa representing subtribes Laeliinae and Arpophyllinae are designated as outgroup. Eight most parsimonious trees were discovered using computer assisted software (length = 230; CI = 0.27). The hypothesis that subtribe Pleurothallidinae has undergone a unilinear reduction in the number of pollinia is not supported by this study. Although the eight-pollinia state as represented by Octomeria apparently is plesiomorphic, the two-pollinia and four-pollinia states arose early in the phylogeny of the subtribe. Both two-and four-pollinia states subsequently reappeared as parallelisms. The six-pollinia state exhibited in Brachionidium is autapomorphic. This cladistic analysis suggests that Pleurothallis is not a natural genus and, perhaps may be divided into several discrete genera.