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Olbermann P.,Institute for Medical Microbiology and Hospital Epidemiology | Olbermann P.,University of Wurzburg | Josenhans C.,Institute for Medical Microbiology and Hospital Epidemiology | Moodley Y.,Max Planck Institute for Infection Biology | And 9 more authors.
PLoS Genetics | Year: 2010

The Helicobacter pylori cag pathogenicity island (cagPAI) encodes a type IV secretion system. Humans infected with cagPAI-carrying H. pylori are at increased risk for sequelae such as gastric cancer. Housekeeping genes in H. pylori show considerable genetic diversity; but the diversity of virulence factors such as the cagPAI, which transports the bacterial oncogene CagA into host cells, has not been systematically investigated. Here we compared the complete cagPAI sequences for 38 representative isolates from all known H. pylori biogeographic populations. Their gene content and gene order were highly conserved. The phylogeny of most cagPAI genes was similar to that of housekeeping genes, indicating that the cagPAI was probably acquired only once by H. pylori, and its genetic diversity reflects the isolation by distance that has shaped this bacterial species since modern humans migrated out of Africa. Most isolates induced IL-8 release in gastric epithelial cells, indicating that the function of the Cag secretion system has been conserved despite some genetic rearrangements. More than one third of cagPAI genes, in particular those encoding cell-surface exposed proteins, showed signatures of diversifying (Darwinian) selection at more than 5% of codons. Several unknown gene products predicted to be under Darwinian selection are also likely to be secreted proteins (e.g. HP0522, HP0535). One of these, HP0535, is predicted to code for either a new secreted candidate effector protein or a protein which interacts with CagA because it contains two genetic lineages, similar to cagA. Our study provides a resource that can guide future research on the biological roles and host interactions of cagPAI proteins, including several whose function is still unknown.© 2010 Olbermann et al. Source

Girardello M.,Northumbria University | Griggio M.,Konrad Lorenz Institute for Ethology | Whittingham M.J.,Northumbria University | Rushton S.P.,Northumbria University
Ecological Research | Year: 2010

Analyzing the relationships between the distribution of animal species and climatic variables is not only important for understanding which factors govern species distribution but also for improving our ability to predict future ecological responses to climate change. In the context of global climate change, amphibians are of particular interest because of their extreme sensitivity to the variation of temperature and precipitation regimes. We analyzed species-climate relationships for 17 amphibian species occurring in Italy using species distribution data at the 10 × 10 km resolution. A machine learning method, Random Forests, was used to model the distribution of amphibians in relation to a set of 18 climatic variables. The results showed that the variables which had the highest importance were those related to precipitation, indicating that precipitation is an important factor in determining amphibian distribution. Future projections showed a complex response of species distributions, emphasizing the potential severity of climate change on the distributions of amphibians in Italy. The species that will decrease the most are those occurring in mountainous and Mediterranean areas. Our results provide some preliminary information that could be useful for amphibian conservation, indicating if future conservation priorities for some species should be enhanced. © The Ecological Society of Japan 2009. Source

News Article
Site: http://phys.org/biology-news/

(Phys.org)—A trio of biologists has conducted a study of one kind of song bird and their results suggest that the females of the species may have lost the desire to sing out of fear it would lead predators to their nest. In their paper published in the journal Biology Letters, Sonia Kleindorfer and Christine Evans, with Flinders University in Australia, and Katharina Mahr with the Konrad Lorenz Institute for Ethology in Austria, describe their study of superb fairy wrens in their native habitat and what they observed. Much study has been conducted regarding male songbirds, the researchers note, but little research has been done to better understand singing in female birds. Traditionally, the thinking has been that males sing to attract the females, thus females have little to no reason to sing. But, as the group also note, a prior study by an international team of researchers back in 2013 showed that approximately 71 percent of female songbirds sing—they just don't do it in the same ways or for the same reasons. In this new effort, the researchers sought to learn more about why female superb fairy wrens sing and when, and if it causes problems for them, such as attracting predators. They set up monitoring stations near 72 nesting sites in the wilds of Australia, home to the birds, and recorded their activities over a two year period. In studying the behavior of both the males and females, the researchers found that the females generally only sang in response to singing from their mate—the birds are monogamous. Males announced their presence when returning to the nest from foraging, the females replied with the same song, though it was muted. The back and forth sing-song between mated pairs was more prominent, the researchers noted, during nest building. To find out if the female returning the call put her eggs or chicks at risk, the team set up some artificial nests with quail eggs in them and played female songs from them, varying the number of calls per hour. Predators ate the eggs 40 percent of the time when the song rate was set at 20 songs per hour, but only did so 20 percent of the time when it was set at 6 calls per hour, showing that such calling did indeed put the offspring at risk. These findings, the researchers propose, suggest that it might be possible that evolution, rather than selecting for male songbird singing, has actually been selecting against female singing. Explore further: Warbling wrens don't just tweet, they sing duets Abstract Female song is an ancestral trait in songbirds, yet extant females generally sing less than males. Here, we examine sex differences in the predation cost of singing behaviour. The superb fairy-wren (Malurus cyaneus) is a Southern Hemisphere songbird; males and females provision the brood and produce solo song year-round. Both sexes had higher song rate during the fertile period and lower song rate during incubation and chick feeding. Females were more likely than males to sing close to or inside the nest. For this reason, female but not male song rate predicted egg and nestling predation. This study identifies a high fitness cost of song when a parent bird attends offspring inside a nest and explains gender differences in singing when there are gender differences in parental care.

Griggio M.,Konrad Lorenz Institute for Ethology | Pilastro A.,University of Padua
Italian Journal of Zoology | Year: 2011

Colourful feathers are important traits in female mate choice in birds because the colour properties of the feathers are often correlated with individual condition during moult. Feather colour can change after moult, and dirt accumulation has been suggested to contribute to this variation. However, we still know little about the influence of dirt on feather colour change, possibly because it is difficult to experimentally manipulate the level of feather dirtiness. We investigated whether reflectance properties of feathers exposed to naturally deposited soil (atmospheric particle deposition such as dust, pollution and smoke) differ from feathers for which this contact was prevented. To achieve this, we compared the spectral colour of throat-breast feathers of European starling, Sturnus vulgaris, kept in the open air (dirty group) with those preserved within a plastic envelope (clean group). Before treatment and three and six weeks after the beginning of the treatment we measured the plumage reflectance of the two groups of feathers. While clean feathers did not change their reflectance spectra, the dirty group showed a reduced reflectance along the entire spectrum (300-700 nm). The reduction in reflectance was particularly pronounced in the UV range (300-400 nm). These preliminary results are consistent with the idea that feather colours are not static signals but are plastic traits. However, much work remains to determine the role of soil and air pollution in altering plumage colouration. © 2011 Unione Zoologica Italiana. Source

Auersperg A.M.I.,University of Vienna | Auersperg A.M.I.,Konrad Lorenz Institute for Ethology | Huber L.,University of Vienna | Gajdon G.K.,Konrad Lorenz Institute for Ethology
Biology Letters | Year: 2011

This study depicts how captive kea, New Zealand parrots, which are not known to use tools in the wild, employ a stick-tool to retrieve a food reward after receiving demonstration trials. Four out of six animals succeeded in doing so despite physical (beak curvature) and ecological (no stick-like materials used during nest construction) constraints when handling elongated objects. We further demonstrate that the same animals can thereafter direct the functional end of a stick-tool into a desired direction, aiming at a positive option while avoiding a negative one. © 2011 The Royal Society. Source

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