Opportunistic foraging strategy of rainbow lizards at a seaside resort in Togo

Rainbow lizards (Agama agama) are common in suburban areas throughout Africa, and have an opportunistic foraging strategy, with arthropods being the main prey source. In a coastal resort in southern Togo, West Africa, several individuals in a population were observed while feeding regularly upon non-natural human-made food (pizza) and showing a clear preference for a given type of food versus others that were offered (‘four cheeses’ being the preferred one). The fact that all monitored individuals fed upon a same type of pizza suggests that they may have some chemical cues attracting them.     

Gene-environment interactions in human disease: nuisance or opportunity?

Many environmental risk factors for common, complex human diseases have been revealed by epidemiologic studies, but how genotypes at specific loci modulate individual responses to environmental risk factors is largely unknown. Gene-environment interactions will be missed in genome-wide association studies and could account for some of the 'missing heritability' for these diseases. In this review, we focus on asthma as a model disease for studying gene-environment interactions because of relatively large numbers of candidate gene-environment interactions with asthma risk in the literature. Identifying these interactions using genome-wide approaches poses formidable methodological problems, and elucidating molecular mechanisms for these interactions has been challenging. We suggest that studying gene-environment interactions in animal models, although more tractable, might not be sufficient to shed light on the genetic architecture of human diseases. Lastly, we propose avenues for future studies to find gene-environment interactions.     

Rab17 Regulates Membrane Trafficking through Apical Recycling Endosomes in Polarized Epithelial Cells

A key feature of polarized epithelial cells is the ability to maintain the specific biochemical composition of the apical and basolateral plasma membrane domains while selectively allowing transport of proteins and lipids from one pole to the opposite by transcytosis. The small GTPase, rab17, a member of the rab family of regulators of intracellular transport, is specifically induced during cell polarization in the developing kidney. We here examined its intracellular distribution and function in both nonpolarized and polarized cells. By confocal immunofluorescence microscopy, rab17 colocalized with internalized transferrin in the perinuclear recycling endosome of BHK-21 cells. In polarized Eph4 cells, rab17 associated with the apical recycling endosome that has been implicated in recycling and transcytosis. The localization of rab17, therefore, strengthens the proposed homology between this compartment and the recycling endosome of nonpolarized cells. Basolateral to apical transport of two membrane-bound markers, the transferrin receptor and the FcLR 5-27 chimeric receptor, was specifically increased in Eph4 cells expressing rab17 mutants defective in either GTP binding or hydrolysis. Furthermore, the mutant proteins stimulated apical recycling of FcLR 5-27. These results support a role for rab17 in regulating traffic through the apical recycling endosome, suggesting a function in polarized sorting in epithelial cells.     

Serum levels of anti-heat shock protein 27 antibodies in patients with chronic liver disease

Heat shock protein 27 (HSP27), an intracellular molecular chaperone, is involved in the pathogenesis of cancer by promoting both tumor cell proliferation and resistance to therapy. HSP27 is also present in the circulation and circulating HSP27 (sHSP27) can elicit an autoimmune response with production of antibodies. Levels of sHSP27 are enhanced in patients with hepatocellular carcinoma (HCC); it is, however, unknown whether changes in HSP27 antibody levels occur in patients with HCC and can be exploited as a circulating biomarker of HCC. Our aim was to assess the potential association between newly diagnosed HCC and serum anti-HSP27 antibody levels. In this cross-sectional study, anti-HSP27 antibody levels were measured in serum samples from 71 HCC patients, 80 subjects with chronic liver disease, and 38 control subjects by immunoenzymatic assay. Anti-HSP27 antibody levels did not differ significantly among groups. However, in patients with chronic active hepatitis/cirrhosis, anti-HSP27 levels were significantly higher in subjects with a positive history of alcoholism (p = 0.03). Our data do not support the hypothesis that anti-HSP27 antibody levels may help identify patients with HCC among subjects with chronic liver disease. However, our finding that alcohol-related liver disease is associated with higher anti-HSP27 levels is novel and deserves further investigations.     

The desire for variety: Italian wall lizard (Podarcis siculus) populations introduced to the United States via the pet trade are derived from multiple native-range sources

Tests of invasion success often require comparisons between introduced and native populations, but determining the native-range sources for introduced populations can be difficult. Molecular markers can help clarify the geographic extent of native-range sources, helping to identify which populations are appropriate for comparative studies. The Italian Wall Lizard (Podarcis siculus) was introduced multiple times to the United States with extant populations in California, Kansas, New Jersey, and New York. We used phylogeographic analysis of mtDNA sequences (cytb gene) for individuals sampled from these introduced populations and across the native range to identify the number of independent introductions and the location of the source populations. Haplotypes sampled from introduced populations were nested within three geographically distinct, well-supported clades that together encompassed a large portion of the native range. Combining these phylogeographic results with documentation of the introductions revealed putative sources: California individuals are derived from Sicily; Kansas and New York populations are from Tuscany near Florence; and the New Jersey population is likely from the Adriatic coastal region, but a more specific locality is not possible. The pet trade dominates the invasion pathway for P. siculus introductions to the US. The genetically and geographically diverse sampling of its native range may be driven by the desire for phenotypic variety in the pet trade, a hypothesis that needs future testing.