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To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.anbehav.2005.07.007 Byline: Nicolas Lecomte, Gregoire Kuntz, Nicolas Lambert, Jean-Paul Gendner, Yves Handrich, Yvon Le Maho, Charles-Andre Bost Abstract: We investigated allofeeding (feeding of offspring by adults other than their own parents) in the king penguin, Aptenodytes patagonicus, a long-lived pelagic bird that faces severe food shortages during its reproduction and in which parents leave their fasting chick in dense creches. A 1-year monitoring of 103 breeding pairs and 70 chicks was carried out in a colony in the Crozet Archipelago. We examined whether allofeeding was common enough to alter survival costs or benefits for both the allofed chicks and the allofeeders. Twenty-two per cent of marked adults allofed more than 65% of all the chicks without repeatedly feeding the same chick. Allofeeding in king penguins benefited allofed chicks by increasing their survival, yet little or no fitness cost was detected among allofeeders. We identified proximal factors affecting allofeeding: (1) the breeding conditions of the population were not unusual; (2) allofeeding occurred mostly when parental provisioning was low; (3) alloparents did not respond to increased begging by regurgitating more meals; (4) allofeeders were mostly failed breeders, although successful breeders occasionally allofed; (5) when the colony was no longer organized into breeder territories, allofeeders preferentially fed chicks that had been reared by close neighbours at the time of brooding. Author Affiliation: (a) Universite du Quebec a Rimouski, Rimouski, Quebec, Canada, Canada (a ) Centre d'Ecologie et de Physiologie Energetiques, Centre National de la Recherche Scientifique, Strasbourg, France (a ) Departement de Biologie and Centre d'Etudes Nordiques, Universite Laval, Quebec, Canada, Canada (As.) Centre d'Etudes Biologiques de Chize, Centre National de la Recherche Scientifique, Beauvoir/Niort, France Article History: Received 25 May 2004; Revised 7 July 2004; Accepted 28 June 2005 Article Note: (miscellaneous) MS. number: A9898R

Parasites are fundamental components within all ecosystems, shaping interaction webs, host population dynamics and behaviour. Despite this, baseline data is lacking to understand the parasite ecology of many Arctic species, including the wolverine (Gulo gulo), a top Arctic predator and scavenger. Here, we combined traditional count methods (i.e. adult helminth recovery, where taxonomy was confirmed by molecular identification) with 18S rRNA high-throughput sequencing to document the wolverine parasite community. Further, we investigated whether the abundance of parasites detected using traditional methods were associated with host metadata, latitude, and longitude (ranging from the northern limit of the boreal forest to the low Arctic and Arctic tundra in Nunavut, Canada). Adult parasites in intestinal contents were identified as Baylisascaris devosi in 72% (n = 39) of wolverines and Taenia spp. in 22% (n = 12), of which specimens from 2 wolverines were identified as T. twitchelli based on COX1 sequence. 18S rRNA high-throughput sequencing on DNA extracted from faeces detected additional parasites, including a pseudophyllid cestode (Diplogonoporus spp. or Diphyllobothrium spp.), two metastrongyloid lungworms (Angiostrongylus spp. or Aelurostrongylus spp., and Crenosoma spp.), an ascarid nematode (Ascaris spp. or Toxocara spp.), a Trichinella spp. nematode, and the protozoan Sarcocystis spp., though each at a prevalence less than 13% (n = 7). The abundance of B. devosi significantly decreased with latitude (slope = -0.68; R2 = 0.17; P = 0.004), suggesting a northerly limit in distribution. We describe B. devosi and T. twitchelli in Canadian wolverines for the first time since 1978, and extend the recorded geographic distribution of these parasites ca 2000 km to the East and into the tundra ecosystem. Our findings illustrate the value of molecular methods in support of traditional methods, encouraging additional work to improve the advancement of molecular screening for parasites. Image 1 • Combining traditional and molecular methods better captures parasite diversity. • B. devosi and Taenia spp. distribution extends ca 2000 km East and into the tundra. • The abundance of B. devosi in wolverines significantly decreases with latitude. • B. devosi and Taenia spp. abundance is not associated with wolverine host metadata. [ABSTRACT FROM AUTHOR]

Abstract: Over time boreal black spruce forests on fine-textured soils in western Quebec, Canada develop very thick forest floors composed of poorly decomposed litter created by the tree and understory layers. These paludified soils are typically waterlogged and cold, and in this fire-mediated landscape, are at least partially consumed by stand replacing fires, which facilitates the establishment of the next generation of trees. Within a context of ecosystem-based management, forest harvest should mimic the dual effects of high severity fire on tree and forest floor biomass. This study was designed to investigate potential factors of forest floor thickness in order to determine the impact of removing only a tree layer, and to suggest strategies to limit paludification in this important forestry region. Forest floor thickness, fire severity, basal area, canopy closure, cover of Sphagnum spp. and ericaceous spp. were measured in black spruce stands across a chronosequence from 50 to 350 years after fire. Fire severity was determined to be a key factor in determining forest floor thickness by path analysis. After high severity fires forest floor thickness was primarily dependant on stand age, but was also positively influenced by Sphagnum spp. cover and negatively influenced by the presence of trembling aspen (Populus tremuloides). These results suggest that forest interventions that do no remove the organic layer may be mimicking low severity fires and promoting poor tree growth and regeneration. Forest floor thickness may be limited by avoiding interventions that open the canopy and may promote the presence of Sphagnum spp. and ericaceous spp., and or by practicing mixed silviculture of trembling aspen and black spruce. However, a balance needs to be maintained between the application of these techniques and the preservation of paludified forests in the landscape. [Copyright &y& Elsevier]

Sea ice loss, disturbance, and habitat modification by humans can alter functional landscape connectivity, with negative impacts on wildlife. Connectivity facilitates movement and gene flow, and contributes to genetic diversity, metapopulation dynamics, and species range-shifts under climate change. For Arctic ungulates, which disperse over large areas including sea ice, environmental change threatens further isolation. Protecting habitat and its linkages is critical and depends on identifying such areas at commensurate, broad scales. Using caribou, the world's most vagile species, we modelled and mapped the drivers of connectivity across ca. 2 million km2 of the Canadian Arctic Archipelago — where the pace of climate change is among the fastest and caribou are threatened with extinction. First, we quantified hierarchical genetic structure and identified two discrete groups. Next, using circuit theory and simultaneous multi-surface optimization, we tested whether land- and sea-scape heterogeneity or geographic distance better accounted for movement and gene flow within each group. We show that anthropogenic interference is far-reaching. High Arctic Peary caribou displayed isolation-by-resistance, where glacier cover, low sea-ice concentrations during fall, and human trails impeded connectivity. In contrast, more southerly barren-ground caribou displayed largely unrestricted gene flow. These divergent outcomes underscore that organism-landscape relationships can vary across space and highlight the importance of intra-specific structure and responses. By leveraging genetic data, our study demonstrates how critical movement pathways can be identified, even for remote and imperilled species. Such knowledge supports broad-scale conservation planning, in particular, by accounting for complex organism-landscape relationships, across vast, heterogeneous ecosystems. [ABSTRACT FROM AUTHOR]

Pancreatic ductal adenocarcinoma (PDAC) is driven by co-existing mutations in KRAS and TP53. However, how these mutations collaborate to promote this cancer is unknown. Here, we uncover sequence-specific changes in RNA splicing enforced by mutant p53 which enhance KRAS activity. Mutant p53 increases expression of splicing regulator hnRNPK to promote inclusion of cytosine-rich exons within GTPase-activating proteins (GAPs), negative regulators of RAS family members. Mutant p53-enforced GAP isoforms lose cell membrane association, leading to heightened KRAS activity. Preventing cytosine-rich exon inclusion in mutant KRAS/p53 PDACs decreases tumor growth. Moreover, mutant p53 PDACs are sensitized to inhibition of splicing via spliceosome inhibitors. These data provide insight into co-enrichment of KRAS and p53 mutations and therapeutics targeting this mechanism in PDAC. • Missense mutations in p53 are associated with specific changes in RNA splicing. • The effects of mutant p53 on RNA splicing are via the RNA binding protein hnRNPK. • Mutant p53 promotes isoforms of GAPs which enhance RAS GTP levels. • Modulating GAP splicing has therapeutic potential in p53 mutant pancreas cancer. Escobar-Hoyos et al. reveal that mutant p53 can regulate RNA splicing to increase KRAS activity in pancreatic cancer. Targeting this splicing axis in mutant p53 pancreatic cancer reduces tumor growth and KRAS signaling, indicating a putative therapeutic strategy for this hard-to-treat cancer. [ABSTRACT FROM AUTHOR]

Alterations in protein-protein interaction networks are at the core of malignant transformation but have yet to be translated into appropriate diagnostic tools. We make use of the kinetic selectivity properties of an imaging probe to visualize and measure the epichaperome, a pathologic protein-protein interaction network. We are able to assay and image epichaperome networks in cancer and their engagement by inhibitor in patients' tumors at single-lesion resolution in real time, and demonstrate that quantitative evaluation at the level of individual tumors can be used to optimize dose and schedule selection. We thus provide preclinical and clinical evidence in the use of this theranostic platform for precision medicine targeting of the aberrant properties of protein networks. • Pathologic protein networks and their engagement in clinic are monitored by imaging • Real-time tumor pharmacometric data are obtained at the level of individual tumors • Theranostic and clinical assay combined provide quantitative tumor measurements • The platform provides dose and schedule information for epichaperome targeting Pillarsetty et al. demonstrate the ability to visualize the epichaperome, a pathologic protein-protein interaction network, and to measure inhibitor engagement from mice and patients at single-tumor resolution in real time, which facilitates the optimization of dose and schedule selection. [ABSTRACT FROM AUTHOR]