Impact of predation on king penguin Aptenodytes patagonicus in Crozet Archipelago

Predation can have major effects on population dynamics, but predator–prey interactions in marine ecosystems have rarely been studied. While the king penguin is one of the most studied seabirds, little is known about the impact of predation on its population dynamics. Here, we determine the impact of the main predators (giant petrels and skuas) on king penguin breeding success taking into account the nocturnal predation of petrels. We found that predation is the most important source of breeding failure for king penguins. The smallest chicks within crèches are the most hunted. The periphery of the colony suffers the highest risk of predation during summer. Our study shows the unequal quality of some areas inside the colony in terms of predation risk and breeding success, and points out the importance of timing in successful breeding.     

Down-regulation of basophil function by human CD200 and human herpesvirus-8 CD200

Human and rodent CD200 are recognized by the inhibitory CD200R, and these molecules play an important role in the regulation of the immune system. Several viruses, such as human herpesvirus-6 (HHV-6), HHV-7, and HHV-8, possess a CD200 homologue, suggesting that these viruses regulate the immune response via CD200R. In this study, we analyzed the effect of human CD200 and the viral CD200 homologues on human CD200R-expressing cells. We found that human CD200R is predominantly expressed on basophils in amounts higher than on other human peripheral blood leukocytes. Furthermore, the viral CD200 homologues as well as human CD200 were recognized by human CD200R, and the activation of basophils was down-regulated by these CD200 proteins. These results suggested that CD200R is an important regulatory molecule of basophil activation. In addition, the presence of CD200 homologues on several viruses suggests a potentially unique relationship between basophil function and viral infection.     

An NDPase links ADAM protease glycosylation with organ morphogenesis in C. elegans

In the nematode Caenorhabditis elegans, the gonad acquires two U-shaped arms through the directed migration of its distal tip cells (DTCs), which are located at the tip of the growing gonad arms. A member of the ADAM (a disintegrin and metalloprotease) family, MIG-17, regulates directional migration of DTCs: MIG-17 is synthesized and secreted from the muscle cells of the body wall, and diffuses to the gonad where it is required for DTC migration. The mig-23 mutation causes defective migration of DTCs and interacts genetically with mig-17. Here, we report that mig-23 encodes a membrane-bound nucleoside diphosphatase (NDPase) required for glycosylation and proper localization of MIG-17. Our findings indicate that an NDPase affects organ morphogenesis through glycosylation of the MIG-17 ADAM protease.     

Peripheral Opioid Antagonist Enhances the Effect of Anti-Tumor Drug by Blocking a Cell Growth-Suppressive Pathway In Vivo

The dormancy of tumor cells is a major problem in chemotherapy, since it limits the therapeutic efficacy of anti-tumor drugs that only target dividing cells. One potential way to overcome chemo-resistance is to “wake up” these dormant cells. Here we show that the opioid antagonist methylnaltrexone (MNTX) enhances the effect of docetaxel (Doc) by blocking a cell growth-suppressive pathway. We found that PENK, which encodes opioid growth factor (OGF) and suppresses cell growth, is predominantly expressed in diffuse-type gastric cancers (GCs). The blockade of OGF signaling by MNTX releases cells from their arrest and boosts the effect of Doc. In comparison with the use of Doc alone, the combined use of Doc and MNTX significantly prolongs survival, alleviates abdominal pain, and diminishes Doc-resistant spheroids on the peritoneal membrane in model mice. These results suggest that blockade of the pathways that suppress cell growth may enhance the effects of anti-tumor drugs.     

Bacillus anthracis Diversity and Geographic Potential across Nigeria,Cameroon and Chad: Further Support of a Novel West African Lineage

Zoonoses, diseases affecting both humans and animals, can exert tremendous pressures on human and veterinary health systems, particularly in resource limited countries. Anthrax is one such zoonosis of concern and is a disease requiring greater public health attention in Nigeria. Here we describe the genetic diversity of Bacillus anthracis in Nigeria and compare it to Chad, Cameroon and a broader global dataset based on the multiple locus variable number tandem repeat (MLVA-25) genetic typing system. Nigerian B. anthracis isolates had identical MLVA genotypes and could only be resolved by measuring highly mutable single nucleotide repeats (SNRs). The Nigerian MLVA genotype was identical or highly genetically similar to those in the neighboring countries, confirming the strains belong to this unique West African lineage. Interestingly, sequence data from a Nigerian isolate shares the anthrose deficient genotypes previously described for strains in this region, which may be associated with vaccine evasion. Strains in this study were isolated over six decades, indicating a high level of temporal strain stability regionally. Ecological niche models were used to predict the geographic distribution of the pathogen for all three countries. We describe a west-east habitat corridor through northern Nigeria extending into Chad and Cameroon. Ecological niche models and genetic results show B. anthracis to be ecologically established in Nigeria. These findings expand our understanding of the global B. anthracis population structure and can guide regional anthrax surveillance and control planning.     

Backbone 1H, 13C,and 15N assignments of yeast Ump1, an intrinsically disordered protein that functions as a proteasome assembly chaperone

Eukaryotic proteasome assembly is a highly organized process mediated by several proteasome-specific chaperones, which interact with proteasome assembly intermediates. In yeast, Ump1 and Pba1-4 have been identified as assembly chaperones that are dedicated to the formation of the proteasome 20S catalytic core complex. The crystal structures of Pba chaperones have been reported previously, but no detailed information has been provided for the structure of Ump1. Thus, to better understand the mechanisms underlying Ump1-mediated proteasome assembly, we characterized the conformation of Ump1 in solution using NMR. Backbone chemical shift data indicated that Ump1 is an intrinsically unstructured protein and largely devoid of secondary structural elements.     

An ethical issue in biodiversity science: The monitoring of penguins with flipper bands

Individual marking is essential to study the life-history traits of animals and to track them in all kinds of ecological, behavioural or physiological studies. Unlike other birds, penguins cannot be banded on their legs due to their leg joint anatomy and a band is instead fixed around a flipper. However, there is now detailed evidence that flipper-banding has a detrimental impact on individuals. It can severely injure flipper tissues, and the drag effect of their flipper bands results in a higher energy expenditure when birds are moving through the water. It also results in lower efficiency in foraging, since they require longer foraging trips, as well as in lower survival and lower breeding success. Moreover, due to the uncertainty of the rate of band loss, flipper bands induce a scientific bias. These problems, which obviously have serious ethical implications, can be avoided with alternative methods such as radiofrequency identification techniques.     

Sex differences in body composition of wintering Mallards (Anas platyrhynchos): possible implications for survival and reproductive performance

Capsule Wintering female Mallards have a higher fat load than males which may compensate for their lower body size and ultimately improve their fitness.

Aims To investigate whether sex-related differences in biological processes in winter are associated with differences in body nutrient storage and flight capabilities and, if so, the possible implications for survival and reproductive performance.

Methods We analysed the body composition and the flight parameters of 35 male and 35 female Mallards wintering in western Europe on the Rhine river.

Results Males were 15% heavier and 18% larger than females, but the latter carried 27% more fat per unit body mass. Relative to body lipid mass, body protein mass was 11% lower for females. Wing loading was 7% lower in females and power loading was similar in both sexes.

Conclusions High lipid mass gives females survival capabilities to food shortage similar to males. This helps sustain them through their prebasic moult and breeding success. Heavier muscles in males compensate for their higher wing loading and thus improve pairing success. Wintering and reproductive strategies in Mallard seem to be closely linked through body reserves.