bluuebunny/crossref_metadata_2025 huggingface dataset:
Duration and outcome of intergroup conflict influences intragroup affiliative behaviour
Authors: Radford Andrew N
Published: September 2008

Theoreticians have long suggested that the amount of intergroup conflict in which a group is involved could influence the level of cooperation or affiliation displayed by its members. Despite the prevalence of intergroup conflicts in many social animal species, however, few empirical studies have investigated this potential link. Here, I show that intragroup allopreening rates are highest in green woodhoopoe (
Phoeniculus purpureus
) groups that have the greatest involvement in intergroup conflict. One reason for this relationship is a post-conflict increase in allopreening, and I demonstrate for the first time that both conflict duration and outcome influence subsequent allopreening rates: group members allopreened more following long conflicts and those they lost compared with short conflicts and those they won, perhaps because the former are more stressful. The increase in affiliative behaviour was the result of more allopreening of subordinate helpers by the dominant breeding pair, which may be because the breeders are trying to encourage helpers to participate in future conflicts; relative group size influences conflict outcome and helpers contribute more to conflicts than do the breeding pair. These results emphasize that our understanding of cooperation and group dynamics can be enhanced by investigations of how intergroup interactions affect intragroup processes.
The earliest stages of ecosystem succession in high-elevation (5000 metres above sea level), recently deglaciated soils
Authors: Schmidt S.K , Reed Sasha C , Nemergut Diana R , Stuart Grandy A , Cleveland Cory C , Weintraub Michael N , Hill Andrew W , Costello Elizabeth K , Meyer A.F , Neff J.C , Martin A.M
Published: September 2008

Global climate change has accelerated the pace of glacial retreat in high-latitude and high-elevation environments, exposing lands that remain devoid of vegetation for many years. The exposure of ‘new’ soil is particularly apparent at high elevations (5000 metres above sea level) in the Peruvian Andes, where extreme environmental conditions hinder plant colonization. Nonetheless, these seemingly barren soils contain a diverse microbial community; yet the biogeochemical role of micro-organisms at these extreme elevations remains unknown. Using biogeochemical and molecular techniques, we investigated the biological community structure and ecosystem functioning of the pre-plant stages of primary succession in soils along a high-Andean chronosequence. We found that recently glaciated soils were colonized by a diverse community of cyanobacteria during the first 4–5 years following glacial retreat. This significant increase in cyanobacterial diversity corresponded with equally dramatic increases in soil stability, heterotrophic microbial biomass, soil enzyme activity and the presence and abundance of photosynthetic and photoprotective pigments. Furthermore, we found that soil nitrogen-fixation rates increased almost two orders of magnitude during the first 4–5 years of succession, many years before the establishment of mosses, lichens or vascular plants. Carbon analyses (pyrolysis-gas chromatography/mass spectroscopy) of soil organic matter suggested that soil carbon along the chronosequence was of microbial origin. This indicates that inputs of nutrients and organic matter during early ecosystem development at these sites are dominated by microbial carbon and nitrogen fixation. Overall, our results indicate that photosynthetic and nitrogen-fixing bacteria play important roles in acquiring nutrients and facilitating ecological succession in soils near some of the highest elevation receding glaciers on the Earth.
Social learning strategies and predation risk: minnows copy only when using private information would be costly
Authors: Webster M.M , Laland K.N
Published: September 2008

Animals can acquire information from the environment privately, by sampling it directly, or socially, through learning from others. Generally, private information is more accurate, but expensive to acquire, while social information is cheaper but less reliable. Accordingly, the ‘costly information hypothesis’ predicts that individuals will use private information when the costs associated with doing so are low, but that they should increasingly use social information as the costs of using private information rise. While consistent with considerable data, this theory has yet to be directly tested in a satisfactory manner. We tested this hypothesis by giving minnows (
Phoxinus phoxinus
) a choice between socially demonstrated and non-demonstrated prey patches under conditions of low, indirect and high simulated predation risk. Subjects had no experience (experiment 1) or prior private information that conflicted with the social information provided by the demonstrators (experiment 2). In both experiments, subjects spent more time in the demonstrated patch than in the non-demonstrated patch, and in experiment 1 made fewer switches between patches, when risk was high compared with when it was low. These findings are consistent with the predictions of the costly information hypothesis, and imply that minnows adopt a ‘copy-when-asocial-learning-is-costly’ learning strategy.
A simple and general explanation for the evolution of altruism
Authors: Fletcher Jeffrey A , Doebeli Michael
Published: September 2008

We present a simple framework that highlights the most fundamental requirement for the evolution of altruism: assortment between individuals carrying the cooperative genotype and the helping behaviours of others with which these individuals interact. We partition the fitness effects on individuals into those due to self and those due to the ‘interaction environment’, and show that it is the latter that is most fundamental to understanding the evolution of altruism. We illustrate that while kinship or genetic similarity among those interacting may generate a favourable structure of interaction environments, it is not a fundamental requirement for the evolution of altruism, and even suicidal aid can theoretically evolve without help ever being exchanged among genetically similar individuals. Using our simple framework, we also clarify a common confusion made in the literature between alternative fitness accounting methods (which may equally apply to the same biological circumstances) and unique causal mechanisms for creating the assortment necessary for altruism to be favoured by natural selection.
War and the evolution of belligerence and bravery
Authors: Lehmann Laurent , Feldman Marcus W
Published: September 2008

Tribal war occurs when a coalition of individuals use force to seize reproduction-enhancing resources, and it may have affected human evolution. Here, we develop a population-genetic model for the coevolution of costly male belligerence and bravery when war occurs between groups of individuals in a spatially subdivided population. Belligerence is assumed to increase an actor's group probability of trying to conquer another group. An actor's bravery is assumed to increase his group's ability to conquer an attacked group. We show that the selective pressure on these two traits can be substantial even in groups of large size, and that they may be driven by two independent reproduction-enhancing resources: additional mates for males and additional territory (or material resources) for females. This has consequences for our understanding of the evolution of intertribal interactions, as hunter-gatherer societies are well known to have frequently raided neighbouring groups from whom they appropriated territory, goods and women.
Three-dimensional images of choanoflagellate loricae
Authors: Leadbeater Barry S.C , Yu QiBin , Kent Joyce , Stekel Dov J
Published: September 2008

Choanoflagellates are unicellular filter-feeding protozoa distributed universally in aquatic habitats. Cells are ovoid in shape with a single anterior flagellum encircled by a funnel-shaped collar of microvilli. Movement of the flagellum creates water currents from which food particles are entrapped on the outer surface of the collar and ingested by pseudopodia. One group of marine choanoflagellates has evolved an elaborate basket-like exoskeleton, the lorica, comprising two layers of siliceous costae made up of costal strips. A computer graphic model has been developed for generating three-dimensional images of choanoflagellate loricae based on a universal set of ‘rules’ derived from electron microscopical observations. This model has proved seminal in understanding how complex costal patterns can be assembled in a single continuous movement. The lorica, which provides a rigid framework around the cell, is multifunctional. It resists the locomotory forces generated by flagellar movement, directs and enhances water flow over the collar and, for planktonic species, contributes towards maintaining cells in suspension. Since the functional morphology of choanoflagellate cells is so effective and has been highly conserved within the group, the ecological and evolutionary radiation of choanoflagellates is almost entirely dependent on the ability of the external coverings, particularly the lorica, to diversify.
Local adaptation in brown trout early life-history traits: implications for climate change adaptability
Authors: Jensen Lasse Fast , Hansen Michael M , Pertoldi Cino , Holdensgaard Gert , Mensberg Karen-Lise Dons , Loeschcke Volker
Published: September 2008

Knowledge of local adaptation and adaptive potential of natural populations is becoming increasingly relevant due to anthropogenic changes in the environment, such as climate change. The concern is that populations will be negatively affected by increasing temperatures without the capacity to adapt. Temperature-related adaptability in traits related to phenology and early life history are expected to be particularly important in salmonid fishes. We focused on the latter and investigated whether four populations of brown trout (Salmo trutta) are locally adapted in early life-history traits. These populations spawn in rivers that experience different temperature conditions during the time of incubation of eggs and embryos. They were reared in a common-garden experiment at three different temperatures. Quantitative genetic differentiation (QST) exceeded neutral molecular differentiation (FST) for two traits, indicating local adaptation. A temperature effect was observed for three traits. However, this effect varied among populations due to locally adapted reaction norms, corresponding to the temperature regimes experienced by the populations in their native environments. Additive genetic variance and heritable variation in phenotypic plasticity suggest that although increasing temperatures are likely to affect some populations negatively, they may have the potential to adapt to changing temperature regimes.
Coral reef fish smell leaves to find island homes
Authors: Dixson Danielle L , Jones Geoffrey P , Munday Philip L , Planes Serge , Pratchett Morgan S , Srinivasan Maya , Syms Craig , Thorrold Simon R
Published: September 2008

Recent studies have shown that some coral reef fish larvae return to natal reefs, while others disperse to distant reefs. However, the sensory mechanisms used to find settlement sites are poorly understood. One hypothesis is that larvae use olfactory cues to navigate home or find other suitable reef habitats. Here we show a strong association between the clownfish
Amphiprion percula
and coral reefs surrounding offshore islands in Papua New Guinea. Host anemones and
A. percula
are particularly abundant in shallow water beneath overhanging rainforest vegetation. A series of experiments were carried out using paired-choice flumes to evaluate the potential role of water-borne olfactory cues in finding islands. Recently settled
A. percula
exhibited strong preferences for: (i) water from reefs with islands over water from reefs without islands; (ii) water collected near islands over water collected offshore; and (iii) water treated with either anemones or leaves from rainforest vegetation. Laboratory reared-juveniles exhibited the same positive response to anemones and rainforest vegetation, suggesting that olfactory preferences are innate rather than learned. We hypothesize that
A. percula
use a suite of olfactory stimuli to locate vegetated islands, which may explain the high levels of self-recruitment on island reefs. This previously unrecognized link between coral reefs and island vegetation argues for the integrated management of these pristine tropical habitats.
Early cortical specialization for face-to-face communication in human infants
Authors: Grossmann Tobias , Johnson Mark H , Lloyd-Fox Sarah , Blasi Anna , Deligianni Fani , Elwell Clare , Csibra Gergely
Published: September 2008

This study examined the brain bases of early human social cognitive abilities. Specifically, we investigated whether cortical regions implicated in adults' perception of facial communication signals are functionally active in early human development. Four-month-old infants watched two kinds of dynamic scenarios in which a face either established mutual gaze or averted its gaze, both of which were followed by an eyebrow raise with accompanying smile. Haemodynamic responses were measured by near-infrared spectroscopy, permitting spatial localization of brain activation (experiment 1), and gamma-band oscillatory brain activity was analysed from electroencephalography to provide temporal information about the underlying cortical processes (experiment 2). The results revealed that perceiving facial communication signals activates areas in the infant temporal and prefrontal cortex that correspond to the brain regions implicated in these processes in adults. In addition, mutual gaze itself, and the eyebrow raise with accompanying smile in the context of mutual gaze, produce similar cortical activations. This pattern of results suggests an early specialization of the cortical network involved in the perception of facial communication cues, which is essential for infants' interactions with, and learning from, others.
Molecular biogeography and diversification of the endemic terrestrial fauna of the Hawaiian Islands
Authors: Cowie Robert H , Holland Brenden S
Published: September 2008

Oceanic islands have played a central role in biogeography and evolutionary biology. Here, we review molecular studies of the endemic terrestrial fauna of the Hawaiian archipelago. For some groups, monophyly and presumed single origin of the Hawaiian radiations have been confirmed (achatinelline tree snails, drepanidine honeycreepers, drosophilid flies,
Havaika
spiders,
Hylaeus
bees,
Laupala
crickets). Other radiations are derived from multiple colonizations (
Tetragnatha
and
Theridion
spiders, succineid snails, possibly
Dicranomyia
crane flies,
Porzana
rails). The geographic origins of many invertebrate groups remain obscure, largely because of inadequate sampling of possible source regions. Those of vertebrates are better known, probably because few lineages have radiated, diversity is far lower and morphological taxonomy permits identification of probable source regions. Most birds, and the bat, have New World origins. Within the archipelago, most radiations follow, to some degree, a progression rule pattern, speciating as they colonize newer from older islands sequentially, although speciation often also occurs within islands. Most invertebrates are single-island endemics. However, among multi-island species studied, complex patterns of diversification are exhibited, reflecting heightened dispersal potential (succineids,
Dicranomyia
). Instances of Hawaiian taxa colonizing other regions are being discovered (
Scaptomyza
flies, succineids). Taxonomy has also been elucidated by molecular studies (
Achatinella
snails, drosophilids). While molecular studies on Hawaiian fauna have burgeoned since the mid-1990s, much remains unknown. Yet the Hawaiian fauna is in peril: more than 70 per cent of the birds and possibly 90 per cent of the snails are extinct. Conservation is imperative if this unique fauna is to continue shedding light on profound evolutionary and biogeographic questions.
Nuclear and mitochondrial sequences confirm complex colonization patterns and clear species boundaries for flightless weevils in the Galápagos archipelago
Authors: Sequeira A.S , Sijapati M , Lanteri A.A , Roque Albelo L
Published: September 2008

Nuclear sequence data were collected from endemic Galápagos species and an introduced close relative, and contrasted with mitochondrial DNA sequences, continuing investigation into the colonization history and modes of diversification in the weevil genusGalapaganus. The current combined phylogeny together with previously published penalized likelihood age estimates builds a complex picture of the archipelago's colonization history. The present reconstruction relies on submerged platforms to explain the early divergence of the young southern Isabela endemics or the Española or San Cristobal populations. Diversity is later built through inter-island divergence starting on older islands and continuing on two simultaneous tracks towards younger islands. The amount of diversity generated through intra-island processes is skewed towards older islands, suggesting that island age significantly influences diversity. Phylogenetic concordance between nuclear and mitochondrial datasets and well-supported monophyletic species in mitochondrial derived topologies appear to reject the possibility of inter-species hybridization. These clear species boundaries might be related to the tight host associations of adult weevils in discrete ecological zones. If shared hosts facilitate hybridization, then host- or habitat-promoted divergences could prevent it, even in the case of species that share islands, since the altitudinal partitioning of habitats minimizes range overlap.
Diversification in a fluctuating island setting: rapid radiation ofOhomopterusground beetles in the Japanese Islands
Authors: Sota Teiji , Nagata Nobuaki
Published: September 2008

The Japanese Islands have been largely isolated from the East Asian mainland since the Early Pleistocene, allowing the diversification of endemic lineages. Here, we explore speciation rates and historical biogeography of the ground beetles of the subgenusOhomopterus(genusCarabus) based on nuclear and mitochondrial gene sequences.Ohomopterusdiverged into 15 species during the Pleistocene. The speciation rate was 1.92 Ma–1and was particularly fast (2.37 Ma–1) in a group with highly divergent genitalia. Speciation occurred almost solely within Honshu, the largest island with complex geography. Species diversity is highest in central Honshu, where closely related species occur parapatrically and different-sized species co-occur. Range expansion of some species in the past has resulted in such species assemblages. Introgressive hybridization, at least for mitochondrial DNA, has occurred repeatedly between species in contact, but has not greatly disturbed species distinctness. Small-island populations of some species were separated from main-island populations only after the last glacial (or the last interglacial) period, indicating that island isolation had little role in speciation. Thus, the speciation and formation of theOhomopterusassemblage occurred despite frequent opportunities for secondary contact and hybridization and the lack of persistent isolation. This radiation was achieved without substantial ecological differentiation, but with marked differentiation in mechanical agents of reproductive isolation (body size and genital morphology).
Phylogeography and ecology of an endemic radiation of Hawaiian aquatic case-bearing moths (Hyposmocoma: Cosmopterigidae)
Authors: Rubinoff Daniel
Published: September 2008

The endemic moth genusHyposmocoma(Lepidoptera: Cosmopterigidae) may be one of the most speciose and ecologically diverse genera in Hawaii. Among this diversity is theHyposmocoma saccophoraclade with previously unrecorded aquatic larvae. I present a molecular phylogeny based on 773 base pairs (bp) of the mitochondrial gene cytochromecoxidase subunit I and 762 bp of the nuclear gene elongation factor 1-α. Topologies were constructed from data using maximum-parsimony, maximum-likelihood and Bayesian search criteria. Results strongly support the monophyly of theH. saccophoraclade and the monophyly of the genusHyposmocoma. TheH. saccophoraclade has single-island endemic species on Oahu, Molokai and West Maui. By contrast, there are three species endemic to Kauai, two being sympatric. TheH. saccophoraclade appears to follow the progression rule, with more basal species on older islands, including the most basal species on 11 Myr-old Necker Island, one of the Northwestern Hawaiian Islands. Aquatic behaviour either evolved recently in the species on the main Hawaiian Islands or was secondarily lost on the arid northwestern Necker Island. The phylogeny suggests thatHyposmocomais older than any of the current main islands, which may, in part, explainHyposmocoma's remarkable diversity.
Cryptic differentiation in the endemic micromoth
Galagete darwini
(Lepidoptera, Autostichidae) on Galápagos volcanoes
Authors: Schmitz Patrick , Cibois Alice , Landry Bernard
Published: September 2008

To gain insight into the early stages of speciation, we reconstructed a DNA-based phylogeny, using combined mitochondrial (cytochrome
c
oxidase subunits I and II: 1008 bp) and nuclear (elongation factor 1-α and wingless: 1062 bp) markers of populations of the moth
Galagete darwini
endemic to the Galápagos, which belongs to an insular radiation similar in size to that of Darwin's finches. Adults of
G. darwini
were collected in the arid lowlands of 11 of the Galápagos Islands (Baltra, Española, Fernandina, Floreana, Isabela, Pinta, Pinzón, San Cristobal, Santa Cruz, Santiago and Seymour) and the humid highlands of a subset of 5 of them (Fernandina, Floreana, Isabela, Santa Cruz and Santiago). The combined phylogeographic analysis surprisingly revealed that
G. darwini
populations at higher elevation on the western islands (Fernandina, Isabela and Santiago) represent a distinct lineage from the one in the low arid zones of these same islands. This is the first reported case in the archipelago of genetic cryptic differentiation correlated with elevation on the western Galápagos volcanoes.
New Caledonia: a very old Darwinian island?
Authors: Grandcolas Philippe , Murienne Jérôme , Robillard Tony , Desutter-Grandcolas Laure , Jourdan Hervé , Guilbert Eric , Deharveng Louis
Published: September 2008

New Caledonia has generally been considered a continental island, the biota of which largely dates back to Gondwanan times owing to its geological origin and the presence of phylogenetic relicts. This view is contradicted by geological evidence indicating long Palaeocene and Eocene submersions and by recent biogeographic and phylogenetic studies, with molecular or geophysical dating placing the biota no older than the Oligocene. Phylogenetic relicts do not provide conclusive information in this respect, as their presence cannot be explained by simple hypotheses but requires assumption of many ad hoc extinction events. The implication of this new scenario is that all the New Caledonian biota colonized the island since 37 Ma Local richness can be explained by local radiation and adaptation after colonization but also by many dispersal events, often repeated within the same groups of organisms. Local microendemism is another remarkable feature of the biota. It seems to be related to recent speciation mediated by climate, orography, soil type and perhaps unbalanced biotic interactions created by colonization disharmonies. New Caledonia must be considered as a very old Darwinian island, a concept that offers many more fascinating opportunities of study.
Medial Position and Counterclockwise Rotation of the Parietal Scalp Hair-Whorl as a Possible Indicator for Non-Right-Handedness
Authors: Schmidt Heinrich , Depner Martin , Kabesch Michael
Published: August 2008

The objective of our study was to assess the association between position and swirling direction of the parietal whorl (PW) and handedness. In 519 patients of a pediatric practice, PWs were located and the swirling direction determined. Of those patients, handedness could be specified in 217. The right-sided PW (n = 347; 70.8%) and the clockwise (CW) swirling type (n = 411; 83.9%) of all participants were predominant in children with one PW. Non-right-handedness (NRH) was found in 40 (18.4%). Medial position of the whorl per se increases the chance for NRH, indifferent of the swirling direction. In patients with counterclockwise (CCW) swirling, the chance of NRH increased 3.5-fold for the right-sided, 5.4-fold for the left-sided, and 12.9-fold for the medial-positioned whorl. We conclude that NRH is associated with the position (medial!) and the swirling direction (CCW!) of the PW.
Unexpected complexity at breakpoint junctions in phenotypically normal individuals and mechanisms involved in generating balanced translocations t(1;22)(p36;q13)
Authors: Gajecka Marzena , Gentles Andrew J. , Tsai Albert , Chitayat David , Mackay Katherine L. , Glotzbach Caron D. , Lieber Michael R. , Shaffer Lisa G.
Published: September 2008

Approximately one in 500 individuals carries a reciprocal translocation. Balanced translocations are usually associated with a normal phenotype unless the translocation breakpoints disrupt a gene(s) or cause a position effect. We investigated breakpoint junctions at the sequence level in phenotypically normal balanced translocation carriers. Eight breakpoint junctions derived from four nonrelated subjects with apparently balanced translocation t(1;22)(p36;q13) were examined. Additions of nucleotides, deletions, duplications, and a triplication identified at the breakpoints demonstrate high complexity at the breakpoint junctions and indicate involvement of multiple mechanisms in the DNA breakage and repair process during translocation formation. Possible detailed nonhomologous end-joining scenarios for t(1;22) cases are presented. We propose that cryptic imbalances in phenotypically normal, balanced translocation carriers may be more common than currently appreciated.
MEDME: An experimental and analytical methodology for the estimation of DNA methylation levels based on microarray derived MeDIP-enrichment
Authors: Pelizzola Mattia , Koga Yasuo , Urban Alexander Eckehart , Krauthammer Michael , Weissman Sherman , Halaban Ruth , Molinaro Annette M.
Published: September 2008

DNA methylation is an important component of epigenetic modifications that influences the transcriptional machinery and is aberrant in many human diseases. Several methods have been developed to map DNA methylation for either limited regions or genome-wide. In particular, antibodies specific for methylated CpG have been successfully applied in genome-wide studies. However, despite the relevance of the obtained results, the interpretation of antibody enrichment is not trivial. Of greatest importance, the coupling of antibody-enriched methylated fragments with microarrays generates DNA methylation estimates that are not linearly related to the true methylation level. Here, we present an experimental and analytical methodology, MEDME (modelingexperimentaldata withMeDIPenrichment), to obtain enhanced estimates that better describe the true values of DNA methylation level throughout the genome. We propose an experimental scenario for evaluating the true relationship in a high-throughput setting and a model-based analysis to predict the absolute and relative DNA methylation levels. We successfully applied this model to evaluate DNA methylation status of normal human melanocytes compared to a melanoma cell strain. Despite the low resolution typical of methods based on immunoprecipitation, we show that model-derived estimates of DNA methylation provide relatively high correlation with measured absolute and relative levels, as validated by bisulfite genomic DNA sequencing. Importantly, the model-derived DNA methylation estimates simplify the interpretation of the results both at single-loci and at chromosome-wide levels.
Interaction of membrane‐bound islet amyloid polypeptide with soluble and crystalline insulin
Authors: Knight Jefferson D. , Williamson Jessica A. , Miranker Andrew D.
Published: September 2008

Islet amyloid polypeptide (IAPP, also known as amylin) is the major protein component of pancreatic amyloid fibers in type II diabetes and is normally cosecreted with insulin from the β‐cells of the pancreas. IAPP forms amyloid fibrils rapidly at concentrations well below those found in vivo, yet progression of type II diabetes occurs over many years. Insulin, a known inhibitor of IAPP fibrillogenesis, exists as a dense crystalline or near‐crystalline core in the secretory vesicle, while IAPP localizes to the region between the crystal and the secretory vesicle membrane. In vitro, IAPP fibrillogenesis is both accelerated by lipid membranes and inhibited by monomeric insulin. In this work, we investigate insulin–IAPP–lipid interactions in vitro under conditions chosen to approximate native secretory vesicle physiology and the amyloid disease state. The effect of insulin on IAPP fibrillogenesis is investigated using fluorescence spectrometry. Additionally, interactions of IAPP and lipids with crystalline insulin are studied using fluorescence microscopy. We find that, while soluble states of insulin and IAPP do not interact significantly, large assemblies of either insulin (crystals) or IAPP (fibers) can lead to stable IAPP–insulin interactions. The results raise the possibility of multiple physiological interactions between these two β‐cell hormones.
Development of tRNA synthetases and connection to genetic code and disease
Authors: Schimmel Paul
Published: September 2008

The genetic code is established by the aminoacylation reactions of aminoacyl tRNA synthetases, where amino acids are matched with triplet anticodons imbedded in the cognate tRNAs. The code established in this way is so robust that it gave birth to the entire tree of life. The tRNA synthetases are organized into two classes, based on their active site architectures. The details of this organization, and other considerations, suggest how the synthetases evolved by gene duplications, and how early proteins may have been statistical in nature, that is, products of a primitive code where one of several similar amino acids was used at a specific position in a polypeptide. The emergence of polypeptides with unique, defined sequences—true chemical entities—required extraordinary specificity of the aminoacylation reaction. This high specificity was achieved by editing activities that clear errors of aminoacylation and thereby prevent mistranslation. Defects in editing activities can be lethal and lead to pathologies in mammalian cells in culture. Even a mild defect in editing is casually associated with neurological disease in the mouse. Defects in editing are also mutagenic in an aging organism and suggest how mistranslation can lead to mutations that are fixed in the genome. Thus, clearance of mischarged tRNAs by the editing activities of tRNA synthetases was essential for development of the tree of life and has a role in the etiology of diseases that is just now being understood.
Resistance of melanized feathers to bacterial degradation: is it really so black and white?
Authors: Gunderson Alex R. , Frame Alicia M. , Swaddle John P. , Forsyth Mark H.
Published: September 2008

Melanins are common feather pigments that contribute to signaling and crypsis. Melanins may also help feathers resist feather‐degrading bacteria (FDB). Two recent studies (Goldstein et al. 2004, Grande et al. 2004) tested the resistance of melanized versus unmelanized feathers to FDB using in vitro experiments, but draw opposite conclusions. Goldstein et al. (2004) concluded that melanized feathers resist FDB more than unmelanized feathers, while Grande et al. (2004) concluded that unmelanized feathers resist FDB more than melanized feathers. To resolve this conflict in the literature, we replicated previous studies but included additional tests not previously used. We inoculated melanized and unmelanized feathers of domestic geese Anser anser domesticus, with the FDB Bacillus licheniformis and measured bacterial activity every two days over two weeks. Three metrics of bacterial activity on feathers were measured: soluble protein content around feathers in solution, bacterial growth on feathers, and loss of feather mass. The latter two metrics were not considered in the aforementioned studies, which indirectly measured bacterial activity. We conducted two trials, one in which feathers were sterilized by autoclaving before inoculation (Goldstein et al. 2004, Grande et al. 2004), and a second in which feathers were sterilized by ethylene oxide gas. This allowed us to test whether autoclaving, done in previous studies, influences bacterial activity on feathers and could confound results. In both trials, unmelanized feathers degraded earlier, supported greater bacterial growth, and lost more mass than melanized feathers. These results support the findings of Goldstein et al. (2004); melanized feathers are more resistant to FDB than unmelanized feathers. Thus, using direct metrics of bacterial activity, we resolve a current conflict in the literature. We also found that autoclaving feathers influences FDB activity on them, and thus autoclaving should be avoided in future studies.
Mycoviruses of filamentous fungi and their relevance to plant pathology
Authors: PEARSON MICHAEL N. , BEEVER ROSS E. , BOINE BARBARA , ARTHUR KIEREN
Published: September 2008

Mycoviruses (fungal viruses) are reviewed with emphasis on plant pathogenic fungi. Based on the presence of virus‐like particles and unencapsidated dsRNAs, mycoviruses are common in all major fungal groups. Over 80 mycovirus species have been officially recognized from ten virus families, but a paucity of nucleic acid sequence data makes assignment of many reported mycoviruses difficult. Although most of the particle types recognized to date are isometric, a variety of morphologies have been found and, additionally, many apparently unencapsidated dsRNAs have been reported. Until recently, most characterized mycoviruses have dsRNA genomes, but ssRNA mycoviruses now constitute about one‐third of the total. Two hypotheses for the origin of mycoviruses of plant pathogens are discussed: the first that they are of unknown but ancient origin and have coevolved along with their hosts, the second that they have relatively recently moved from a fungal plant host into the fungus. Although mycoviruses are typically readily transmitted through asexual spores, transmission through sexual spores varies with the host fungus. Evidence for natural horizontal transmission has been found. Typically, mycoviruses are apparently symptomless (cryptic) but beneficial effects on the host fungus have been reported. Of more practical interest to plant pathologists are those viruses that confer a hypovirulent phenotype, and the scope for using such viruses as biocontrol agents is reviewed. New tools are being developed based on host genome studies that will help to address the intellectual challenge of understanding the fungal–virus interactions and the practical challenge of manipulating this relationship to develop novel biocontrol agents for important plant pathogens.
Seasonal inventory and status of flying insects, in Kihansi Gorge, Tanzania
Authors: Msyani Edward K. , Lazaro Johanna , Castor Oliver Nyakunga , Chambegga Omoury Amiri
Published: September 2008

Sampling of flying insects in Kihansi Gorge was conducted in six micro‐habitats namely Lower, Upper, Main, Mid‐Gorge and Mhalala Spray Wetlands and adjacent forest. The four traps used were, malaise, pitfall, light and artificial substrate sampler, besides sweep netting and beating. In the wet season, 65,549 flying insects (65.13%) were recorded when compared to 35,633 flying insects (34.87%) in dry season. At its peak, 29,783 flying insects (29.15%) were recorded at the start of wet season (December 2004). The abundance value was significant (χ2 = 1794.98, d.f. = 5, P ≤ 0.001). The favourable weather condition at the beginning of the wet season might have triggered emergence of high numbers of winged insects like ants, to facilitate migration through dispersal and reproduction, and some aquatic insects (Plecoptera, Odonata and Trichoptera) moulted and entered into terrestrial life to raise terrestrial abundance. No association was recorded between abundance of flying insects and amphibians (Kihansi Spray Toad; Nectophynoides asperginis), for Mid‐Gorge and Main Spray Wetlands (r = −0.71, n = 4, P = 0.147 and r = −0.69, n = 5, P = 0.201) respectively.
Use of pharmacokinetic/ pharmacodynamic modelling for starting dose selection in first‐in‐human trials of high‐risk biologics
Authors: Agoram Balaji M.
Published: September 2008

WHAT IS ALREADY KNOWN ABOUT THIS SUBJECT

• Recent regulatory guidance has highlighted the importance of using pharmacokinetic–pharmacodynamic (PK–PD) modelling in the selection of starting doses in first‐in‐human trials of high‐risk biologics.

• However, limited examples exist in literature illustrating this procedure.

WHAT THIS STUDY ADDS

• An interpretation of the recommended dose‐selection methodology and the minimum anticipated biological effect level (MABEL) principle, contained in the updated European Medicines Agency guidance on risk‐mitigation strategies for first‐in‐human studies, is presented.

• Some literature and simulation‐based examples of the application of PK–PD modelling principles to starting dose selection using in vitro and in vivo data under the MABEL paradigm are highlighted, along with the advantages and limitations of this approach.

AIMS To illustrate the use of pharmacokinetic–pharmacodynamic (PK–PD) models to select rational starting doses in clinical trials within the minimum anticipated biological effect level (MABEL) principle using literature data and through simulations.

METHODS The new European Medicines Agency guidance on starting dose selection of high‐risk biologics was analysed considering the basic pharmacological properties and preclinical testing limitations of many biologics. The MABEL approach to dose selection was illustrated through simulations and through literature‐reported examples on the selection of starting doses for biologics such as antibodies based on in vitro biomarker data, in vivo PK and PK–PD data.

RESULTS Literature reports indicating the use of preclinical pharmacological and toxicological data to select successfully safe starting doses in line with the MABEL principle are summarized. PK–PD model‐based simulations of receptor occupancy for an anti‐IgE antibody system indicate that the relative abundance of IgE in animal models and patients and the turnover rate of the IgE–antibody complex relative to the off‐rate of the antibody from IgE are important determinants of in vivo receptor occupancy.

CONCLUSIONS Mechanistic PK–PD models are capable of integrating preclinical in vitro and in vivo data to select starting doses rationally in first‐in‐human trials. Biological drug–receptor interaction dynamics is complex and multiple factors affect the dose–receptor occupancy relationship. Thus, these factors should be taken into account when selecting starting doses.
Mothering in the context of domestic violence: the pervasiveness of a deficit model of mothering
Authors: Lapierre Simon
Published: September 2008

Despite growing concerns with the situation of children exposed to domestic violence, and although women have been seen as central in the welfare of their children, limited attention has been paid to the issue of mothering in this context. This paper examines how concerns regarding abused women's mothering have been articulated in the academic literature on children's exposure to domestic violence, and argues that the dominant discourse in this area has been characterized by a deficit model of mothering. Implications of the pervasiveness of a deficit model for child welfare policies and practices are highlighted. Finally, this paper identifies key elements that should be considered in the development of a feminist perspective on mothering in the context of domestic violence, which could lead to less blaming and more supportive practices.
Lessons learnt? Abuse in residential child care in Scotland
Authors: Sen Robin , Kendrick Andrew , Milligan Ian , Hawthorn Moyra
Published: September 2008

This paper draws on work carried out by Sen, Kendrick, Milligan and Hawthorn commissioned as pert of the Historic Abuse Systemic Review by the Scottish Executive in 2007. It considers the evidence‐based regarding abuse in residential child care from 1945 with a specific focus on Scotland. It reviews the context set for residential child care post‐1945 by the Clyde and Curtis reports, outlines how the residential child care sector developed following this, provides an overview of evidence and awareness of abuse in residential child care establishments after the 1948 Children's Act, giving particular consideration to the public inquiries and reviews of residential child care which there have been in Scotland, explores research evidence regarding the safety of convictions of residential child care workers found guilty of child abuse, and provides an overview of the main policy and practice developments which there have subsequently been in Scotland. The paper concludes by considering the progress that has been made in developing safeguards in Scotland and identifying areas where further research and development are required.
Allergen specific responses in cord and adult blood are differentially modulated in the presence of endotoxins
Authors: Eiwegger T. , Mayer E. , Brix S. , Schabussova I. , Dehlink E. , Bohle B. , Barkholt V. , Szépfalusi Z.
Published: September 2008

Background
Endotoxins are common contaminants in allergen preparations and affect antigen‐specific cellular responses. Distinct effects of endotoxin on cells in human umbilical cord and adult blood are poorly defined.

Objectives
To examine the effect of endotoxins in allergen preparations on cellular responses in human cord and peripheral blood (PB).

Methods
The endotoxin content in β lactoglobulin (BLG), the peanut allergen Ara h 1 and the major birch pollen allergen Bet v 1 was assessed. Proliferation and cytokine response of mononuclear cells towards contaminated and lipopolysaccharide (LPS)‐free allergens were evaluated at different time‐points. Fractions of contaminated BLG were generated and assayed on their immuno‐stimulatory capacity. The involvement of toll‐like receptor (TLR) 2 and 4 was investigated by blocking antibodies and TLR‐transfected human embryonic kidney cells.

Results
The proliferative response of cord blood (CB)‐derived mononuclear cells towards allergen‐preparations at day 3 was related to the level of LPS contamination. At day 7, proliferation was also detected in the absence of endotoxin. Cytokine production in CB was strongly affected by the content of endotoxin, TLR‐4 dependent and not related to the allergen content. Allergen‐ and endotoxin‐induced proliferative responses were generally significantly higher in CB than in adult blood.

Conclusion
Endotoxins in allergen preparations confound allergen‐specific cellular responses. The impact of these contaminations varies with the blood source (CB vs. PB), the type of allergen and is time‐ and dose‐dependent.
Impacts of extreme winter warming in the sub‐Arctic: growing season responses of dwarf shrub heathland
Authors: BOKHORST S. , BJERKE J. W. , BOWLES F. W. , MELILLO J. , CALLAGHAN T. V. , PHOENIX G. K.
Published: September 2008

Climate change scenarios predict an increased frequency of extreme climatic events. In Arctic regions, one of the most profound of these are extreme and sudden winter warming events in which temperatures increase rapidly to above freezing, often causing snow melt across whole landscapes and exposure of ecosystems to warm temperatures. Following warming, vegetation and soils no longer insulated below snow are then exposed to rapidly returning extreme cold. Using a new experimental facility established in sub‐Arctic dwarf shrub heathland in northern Sweden, we simulated an extreme winter warming event in the field and report findings on growth, phenology and reproduction during the subsequent growing season. A 1‐week long extreme winter warming event was simulated in early March using infrared heating lamps run with or without soil warming cables. Both single short events delayed bud development of Vaccinium myrtillus by up to 3 weeks in the following spring (June) and reduced flower production by more than 80%: this also led to a near‐complete elimination of berry production in mid‐summer. Empetrum hermaphroditum also showed delayed bud development. In contrast, Vaccinium vitis‐idaea showed no delay in bud development, but instead appeared to produce a greater number of actively growing vegetative buds within plots warmed by heating lamps only. Again, there was evidence of reduced flowering and berry production in this species. While bud break was delayed, growing season measurements of growth and photosynthesis did not reveal a differential response in the warmed plants for any of the species. These results demonstrate that a single, short, extreme winter warming event can have considerable impact on bud production, phenology and reproductive effort of dominant plant species within sub‐Arctic dwarf shrub heathland. Furthermore, large interspecific differences in sensitivity are seen. These findings are of considerable concern, because they suggest that repeated events may potentially impact on the biodiversity and productivity of these systems should these extreme events increase in frequency as a result of global change. Although climate change may lengthen the growing season by earlier spring snow melt, there is a profound danger for these high‐latitude ecosystems if extreme, short‐lived warming in winter exposes plants to initial warm temperatures, but then extreme cold for the rest of the winter. Work is ongoing to determine the longer term and wider impacts of these events.
Mycorrhizal fungi reduce the negative effects of nitrogen enrichment on plant community structure in dune grassland
Authors: Van Der HEIJDEN MARCEL G. A. , VERKADE SEBASTIAAN , De BRUIN SUSANNE J.
Published: September 2008

Nitrogen (N) inputs to ecosystems have increased worldwide, often leading to large changes in plant community structure and reducing plant diversity. Yet, the interaction of increased N availability with other factors that determine plant community composition, are still poorly understood. Here, we test whether the impact of N addition on plant communities depends on the presence of arbuscular mycorrhizal fungi (AMF). AMF are widespread plant symbionts that facilitate growth of many plant species. We hypothesize that AM fungi reduce the negative impact of N addition on plant communities by supporting growth of species that are sensitive to N enrichment.We established experimental grassland microcosms consisting of 18 plant species. These microcosms were subjected to high and low N supply and were inoculated with AMF or remained nonmycorrhizal. Both N addition and AMF had a big impact on plant community composition, but with opposite effects. N addition induced a 2.8‐fold increase in grass biomass and reduced legume biomass. Grasses dominated the microcosms at high N supply, especially when AMF were absent. In contrast, AMF enhanced biomass of all legumes species (on average 6.8‐fold) and reduced the relative abundance of grasses. The proportion of legume biomass out of total shoot biomass at high N supply was 19% with AMF and only 3% without AMF. Our results show that responses of plant communities to N enrichment depend on AMF and that AMF can reduce the negative impact of increased N availability on plant community structure by reducing grass dominance.