Unusual growth pattern in the Frasnian alveolitids (Tabulata) from the Holy Cross Mountains (Poland)

Abstract: Growth periodicity is a phenomenon occurring in fossil and modern corals. The most apparent feature is growth banding, and environmental changes are broadly accepted as controls on this phenomenon. If environment controls the growth, then all corallites within a colony should repeat the same growth pattern, as individuals are clones and must have shared the same environment. A study on several species of Alveolitidae (Anthozoa, Tabulata) from the Late Devonian (Early Frasnian) of the Holy Cross Mountains (Poland) shows that the growth pattern varies between neighbouring individuals within the same corallum. This contradicts observations of closely related Favositida as demonstrated on Pachyfavosites sp. from the Givetian of Avesnois, France, where neighbouring individuals repeat the same pattern. Therefore, environmental control on growth rhythm in Alveolitidae can be excluded; the causes of differences between individuals remain unknown.     

Cutting edge: a naturally occurring mutation in CD1e impairs lipid antigen presentation

The human CD1a-d proteins are plasma membrane molecules involved in the presentation of lipid Ags to T cells. In contrast, CD1e is an intracellular protein present in a soluble form in late endosomes or lysosomes and is essential for the processing of complex glycolipid Ags such as hexamannosylated phosphatidyl-myo-inositol, PIM(6). CD1e is formed by the association of beta(2)-microglobulin with an alpha-chain encoded by a polymorphic gene. We report here that one variant of CD1e with a proline at position 194, encoded by allele 4, does not assist PIM(6) presentation to CD1b-restricted specific T cells. The immunological incompetence of this CD1e variant is mainly due to inefficient assembly and poor transport of this molecule to late endosomal compartments. Although the allele 4 of CD1E is not frequent in the population, our findings suggest that homozygous individuals might display an altered immune response to complex glycolipid Ags.     

Plant hosts and parasitoid associations of leaf mining flies (Diptera: Agromyzidae) in the Canberra region of Australia

Abstract  Many leaf mining flies (Diptera: Agromyzidae) are important economic pests of agricultural crops and ornamental plants, and species-rich hymenopteran parasitoid complexes are important in their control. Australian agromyzids are poorly studied, and little is known about their host plants, ecology or natural enemies. We surveyed native and naturalised species of leaf mining flies in Tallaganda National Park, New South Wales and the Australian Capital Territory. Malaise and emergence trapping in Tallaganda yielded 70 agromyzid specimens from six species in four genera: Cerodontha Rondani, Liriomyza Mik, Phytoliriomyza Hendel and Phytomyza Fallen. Of the six species collected, three are Australasian species, two are naturalised species introduced from Europe and one could not be determined to species. The Australian Cerodontha ( Cerodontha ) milleri Spencer represented most of the individuals caught in both Malaise and emergence traps. A total of 163 agromyzid and 98 parasitic wasp specimens were reared from plant samples with agromyzid mines in the Canberra region. Most agromyzids and parasitoids were reared from the weed Sonchus oleraceus L. (Asteraceae). All the agromyzids reared belonged to two introduced species of the genera Phytomyza and Chromatomyia Hardy. The biodiversity of parasitic wasps reared was high with 14 species from seven genera and three families. Hemiptarsenus varicornis (Girault) (Eulophidae), a widespread Old World agromyzid parasitoid, was the most numerous parasitoid reared in our survey.     

A model invalidation-based approach for elucidating biological signalling pathways,applied to the chemotaxis pathway in R. sphaeroides

Background  

Developing methods for understanding the connectivity of signalling pathways is a major challenge in biological research. For this purpose, mathematical models are routinely developed based on experimental observations, which also allow the prediction of the system behaviour under different experimental conditions. Often, however, the same experimental data can be represented by several competing network models.