bluuebunny/crossref_metadata_2025_split huggingface dataset:
Autoantibodies to myelin basic protein (MBP) in healthy individuals and in patients with multiple sclerosis: a role in regulating cytokine responses to MBP
Authors: Hedegaard Chris J. , Chen Ning , Sellebjerg Finn , Sørensen Per Soelberg , Leslie R. Graham Q. , Bendtzen Klaus , Nielsen Claus H. 
Published: December 2008

SummaryAnti‐myelin basic protein (‐MBP) autoantibodies have generally been considered to be absent from sera from healthy individuals, but to be detectable in sera from some patients with multiple sclerosis (MS). However, their pathogenic role is uncertain. We demonstrate the presence of MBP‐reactive autoantibodies in sera from 17 healthy individuals and 17 MS patients. The addition of MBP to the sera caused a dose‐dependent deposition of MBP and co‐deposition of immunoglobulin M (IgM) and fragments of complement component 3 (C3) on allogeneic monocytes. Calcium chelation abrogated the immunoglobulin deposition, indicating that formation of complement‐activating immune complexes played a role in the binding process. Furthermore, MBP elicited tumour necrosis factor (TNF)‐α and interleukin (IL)‐10 production by normal mononuclear cells in the presence of serum from both patients and controls. Mononuclear cells from MS patients responded to MBP with the production of interferon (IFN)‐γ, IL‐4 and IL‐5, in addition to TNF‐α and IL‐10. The production of IFN‐γ and IL‐5 was increased when MS serum was added rather than normal serum. Denaturation of MBP strongly inhibited MBP deposition and the MBP‐induced IgM deposition and cytokine production, indicating that these events were facilitated by autoantibodies recognizing conformational epitopes on MBP. We infer that MBP‐elicited TNF‐α and IL‐10 responses are promoted to equal extents by naturally occurring MBP autoantibodies and autoantibodies contained in MS sera. However, the latter seem to be more efficient in facilitating the production of IFN‐γ and IL‐5.
The collision of the Indian plate with Asia: molecular evidence for its impact on the phylogeny of freshwater crabs (Brachyura: Potamidae)
Authors: Shih Hsi‐Te , Yeo Darren C. J. , Ng Peter K. L. 
Published: December 2008

AbstractAim  We used molecular data to answer the following questions: (1) Is morphology‐based (and to some extent, geography‐based) classification of the freshwater crab family Potamidae congruent with a molecular phylogeny? (2) What historical biogeographical event could have shaped this phylogeny?Location  Material from the entire geographical range of the family Potamidae was analysed, including specimens from East Asia (China, Taiwan, the Ryukyus), Southeast Asia, South Asia (northern India, the Middle East and Near East), North Africa, and southern Europe.Methods  Mitochondrial DNA sequences encoding 503 base pairs (excluding the variable regions) of the large subunit rRNA (16S rRNA) gene were obtained from 72 species belonging to 49 potamid genera, representing 51% of all known genera in this species‐rich family. Sequences were compared by means of phylogenetic analyses (minimum evolution, Bayesian inference, maximum likelihood and maximum parsimony) and Bayesian relaxed molecular clock estimates.Results  The family Potamidae was found to be monophyletic with two major lineages, and there was support for the recognition of two mostly allopatric subfamilies, Potaminae and Potamiscinae. This is largely consistent with the current classification proposed. The ‘Potamiscinae’ clade comprised three subclades: (1) a well‐supported ‘eastern Asia’ subclade that included species from the eastern part of the range (China, Taiwan, the Ryukyus, the Philippines, Indochina, Malay Peninsula, northern India and Myanmar/Burma); (2) a weakly supported ‘Sunda Shelf islands’ subclade that included species from the larger Southeast Asian islands on the Sunda Shelf (Borneo, Sumatra and Java); and (3) a ‘Socotra’ subclade that comprised only Socotrapotamon from Socotra Island, off the north‐east coast of Africa.Main conclusions  The discrete distribution of the two subfamilies in Europe/Asia is hypothesized to be the result of vicariance due to the collision of the Indian tectonic plate with the Asian continent, and the orogeny that caused the separation of the two freshwater crab lineages around 22.8 Ma. Within the Potamiscinae, the ‘Sunda Shelf islands’ subclade separated from other potamiscines around 21.1 Ma; and the endemic fauna of the East Asian islands (Taiwan, the Ryukyus and mainland Japan) was isolated from the Asian continent c. 8.4 Ma, following the opening of the Okinawa Trough. The ‘Socotra’ subclade diverged from the ‘eastern Asia’ subclade at 19.1 Ma during the Miocene. Its taxonomic position, however, remains unclear as the members of this clade possess the key potamine character of a transverse ridge on thoracic sternite 8, suggesting that this may in fact be a relict potamid group.
Five questions on ecological speciation addressed with individual‐based simulations
Authors: THIBERT‐PLANTE X. , HENDRY A. P. 
Published: December 2008

AbstractWe use an individual‐based simulation model to investigate factors influencing progress toward ecological speciation. We find that environmental differences can quickly lead to the evolution of substantial reproductive barriers between a population colonizing a new environment and the ancestral population in the old environment. Natural selection against immigrants and hybrids was a major contributor to this isolation, but the evolution of sexual preference was also important. Increasing dispersal had both positive and negative effects on population size in the new environment and had positive effects on natural selection against immigrants and hybrids. Genetic divergence at unlinked, neutral genetic markers was low, except when environmental differences were large and sexual preference was present. Our results highlight the importance of divergent selection and adaptive divergence for ecological speciation. At the same time, they reveal several interesting nonlinearities in interactions between environmental differences, sexual preference, dispersal and population size.
Egg jelly influences sperm motility in the externally fertilizing frog,Crinia georgiana
Authors: SIMMONS L. W. , ROBERTS J. D. , DZIMINSKI M. A. 
Published: December 2008

AbstractRecentin vitrofertilization studies have revealed female and male × female interaction effects on the probability of fertilization. These findings suggest a mechanism of cryptic female choice via sperm–egg interactions. The egg jelly of anuran amphibians contains proteins that facilitate the chemoattraction and binding of sperm for fertilization. Here we show that egg jelly also influences the onset of motility and swimming velocity of motile sperm in the frogCrinia georgiana. Moreover, we found significant among female variation in the effects of egg jelly on sperm motility. We discuss this finding with respect to male and female effects on nonrandom fertilization observed in this species.
Evaluation of offspring size–number invariants in 12 species of lizard
Authors: ULLER T. , WHILE G. M. , WAPSTRA E. , WARNER D. A. , GOODMAN B. A. , SCHWARZKOPF L. , LANGKILDE T. , DOUGHTY P. , RADDER R. S. , ROHR D. H. , BULL C. M. , SHINE R. , OLSSON M. 
Published: December 2008

AbstractThe optimal division of resources into offspring size vs. number is one of the classic problems in life‐history evolution. Importantly, models that take into account the discrete nature of resource division at low clutch sizes suggest that the variance in offspring size should decline with increasing clutch size according to an invariant relationship. We tested this prediction in 12 species of lizard with small clutch sizes. Contrary to expectations, not all species showed a negative relationship between variance in offspring size and clutch size, and the pattern significantly deviated from quantitative predictions in five of the 12 species. We suggest that the main limitation of current size–number models for small clutch sizes is that they rely on assumptions of hierarchical allocation strategies with independence between allocation decisions. Indeed, selection may favour alternative mechanisms of reproductive allocation that avoid suboptimal allocation imposed by the indivisible fraction at low clutch sizes.
Demographic factors and genetic variation influence population persistence under environmental change
Authors: WILLI YVONNE , HOFFMANN ARY A. 
Published: December 2008

AbstractPopulation persistence has been studied in a conservation context to predict the fate of small or declining populations. Persistence models have explored effects on extinction of random demographic and environmental fluctuations, but in the face of directional environmental change they should also integrate factors affecting whether a population can adapt. Here, we examine the population‐size dependence of demographic and genetic factors and their likely contributions to extinction time under scenarios of environmental change. Parameter estimates were derived from experimental populations of the rainforest species, Drosophila birchii, held in the lab for 10 generations at census sizes of 20, 100 and 1000, and later exposed to five generations of heat‐knockdown selection. Under a model of directional change in the thermal environment, rapid extinction of populations of size 20 was caused by a combination of low growth rate (r) and high stochasticity in r. Populations of 100 had significantly higher reproductive output, lower stochasticity in r and more additive genetic variance (VA) than populations of 20, but they were predicted to persist less well than the largest size class. Even populations of 1000 persisted only a few hundred generations under realistic estimates of environmental change because of low VA for heat‐knockdown resistance. The experimental results document population‐size dependence of demographic and adaptability factors. The simulations illustrate a threshold influence of demographic factors on population persistence, while genetic variance has a more elastic impact on persistence under environmental change.
Male–male competition, female mate choice and their interaction: determining total sexual selection
Authors: HUNT JOHN , BREUKER CASPER J. , SADOWSKI JENNIFER A. , MOORE ALLEN J. 
Published: December 2008

AbstractEmpirical studies of sexual selection typically focus on one of the two mechanisms of sexual selection without integrating these into a description of total sexual selection, or study total sexual selection without quantifying the contributions of all of the mechanisms of sexual selection. However, this can provide an incomplete or misleading view of how sexually selected traits evolve if the mechanisms of sexual selection are opposing or differ in form. Here, we take a two‐fold approach to advocate a direction for future studies of sexual selection. We first show how a quantitative partitioning and examination of sexual selection mechanisms can inform by identifying illustrative studies that describe both male–male competition and female mate choice acting on the same trait. In our sample, the most common trait where this occurred was body size, and selection was typically linear. We found that male–male competition and female mate choice can be reinforcing or opposing, although the former is most common in the literature. The mechanisms of sexual selection can occur simultaneously or sequentially, and we found they were more likely to be opposing when the mechanisms operated sequentially. The degree and timing that these mechanisms interact have important implications for the operation of sexual selection and needs to be considered in designing studies. Our examples highlight where empirical data are needed. We especially lack standardized measures of the form and strength of selection imposed by each mechanism of sexual selection and how they combine to determine total sexual selection. Secondly, using quantitative genetic principles, we outline how the selection imposed by individual mechanisms can be measured and combined to estimate the total strength and form of sexual selection. We discuss the evolutionary consequences of combining the mechanisms of sexual selection and interpreting total sexual selection. We suggest how this approach may result in empirical progress in the field of sexual selection.
Metapopulation persistence in fragmented landscapes: significant interactions between genetic and demographic processes
Authors: THEODOROU K. , SOUAN H. , COUVET D. 
Published: December 2008

AbstractWe formulated a mathematical model in order to study the joint influence of demographic and genetic processes on metapopulation viability. Moreover, we explored the influence of habitat structure, matrix quality and disturbance on the interplay of these processes. We showed that the conditions that allow metapopulation persistence under the synergistic action of genetic and demographic processes depart significantly from predictions based on a mere superposition of the effects of each process separately. Moreover, an optimal dispersal rate exists that maximizes the range of survival rates of dispersers under which metapopulation persists and at the same time allows the largest sustainable patch removal and patch‐size reduction. The relative impact of patch removal and patch‐size reduction depends both on matrix quality and the dispersal strategy of the species: metapopulation persistence is more affected by patch‐size reduction (patch removal) for low (high)‐dispersing species, in presence of a low (high) quality matrix. Avoidance of inbreeding, through increased dispersal when the rate of inbreeding in a population is large, has positive effects on low‐dispersing species, but impairs the persistence of high‐dispersing species. Finally, size heterogeneity between patches largely influences metapopulation dynamics; the presence of large patches, even at the expense of other patches being smaller, can have positive effects on persistence in particular for species of low dispersing ability.
Fitness and the level of homozygosity in a social insect
Authors: HAAG‐LIAUTARD C. , VITIKAINEN E. , KELLER L. , SUNDSTRÖM L. 
Published: December 2008

AbstractTo date very few studies have addressed the effects of inbreeding in social Hymenoptera, perhaps because the costs of inbreeding are generally considered marginal owing to male haploidy whereby recessive deleterious alleles are strongly exposed to selection in males. Here, we present one of the first studies on the effects of queen and worker homozygosity on colony performance. In a wild population of the ant Formica exsecta, the relative investment of single‐queen colonies in sexual production decreased with increased worker homozygosity. This may either stem from increased homozygosity decreasing the likelihood of diploid brood to develop into queens or a lower efficiency of more homozygous workers at feeding larvae and thus a lower proportion of the female brood developing into queens. There was also a significant negative association between colony age and the level of queen but not worker homozygosity. This association may stem from inbreeding affecting queen lifespan and/or their fecundity, and thus colony survival. However, there was no association between queen homozygosity and colony size, suggesting that inbreeding affects colony survival as a result of inbred queens having a shorter lifespan rather than a lower fecundity. Finally, there was no significant association between either worker or queen homozygosity and the probability of successful colony founding, colony size and colony productivity, the three other traits studied. Overall, these results indicate that inbreeding depression may have important effects on colony fitness by affecting both the parental (queen) and offspring (worker) generations cohabiting within an ant colony.
Lovesick: immunological costs of mating to male sagebrush crickets
Authors: LEMAN J. C. , WEDDLE C. B. , GERSHMAN S. N. , KERR A. M. , OWER G. D. , ST JOHN J. M. , VOGEL L. A. , SAKALUK S. K. 
Published: December 2008

AbstractA growing body of evidence suggests that resources invested in reproduction often come at the expense of the ability to mount an immune response. During mating, female sagebrush crickets, Cyphoderris strepitans, consume the ends of the male’s hind wings and ingest his haemolymph. Previous research has shown that this behaviour impairs the ability of males to secure additional matings. One hypothesis to account for this effect is that wing wounding triggers an energetically costly immune response, such that nonvirgin males are unable to sustain the costly acoustical signalling needed to attract additional females. To test this hypothesis, we injected virgin males with lipopolysaccharides (LPS) to provoke an immune response, and monitored their mating success in the field. LPS‐injected virgin males took significantly longer to mate than sham‐injected virgin males, and spent significantly less time calling. We also compared virgin, nonvirgin and experimentally wing‐wounded virgin males with respect to: (1) their ability to encapsulate a foreign invader via the accumulation of haemocytes and deposition of melanin and (2) baseline levels of phenoloxidase (PO), a key enzyme in the biochemical cascade leading to the production of melanin. Although encapsulation ability did not differ with reproductive experience, virgin males had significantly higher levels of PO than either nonvirgin or experimentally wing‐wounded virgin males. These results suggest that wing‐wounding alone is sufficient to impair male immunity, and that males trade‐off investment in reproduction and immunity.
On the mechanism of rejuvenation of ageing detached bean leaves by low‐concentration stressors
Authors: Nyitrai P. , Kovács E. , Király I. , Óvári M. , Keresztes Á. 
Published: December 2008

AbstractThe effect of low concentrations of some stress‐inducing compounds of different toxicity and chemical nature, such as Cd and Pb salts or DCMU, was investigated on the senescence of chloroplasts in detached primary leaves of bean (Phaseolus vulgaris L.). After 1 week of senescence followed by root development from the petiole, these agents stimulated chlorophyll accumulation and photosynthetic activity (14CO2 fixation) as compared to the control, thus inducing rejuvenation. Low‐concentration stressors increased the level of active cytokinins in roots and leaves during the treatment, as monitored by the Amaranthus betacyanin bioassay and high‐pressure liquid chromatography. The lithium ion, an inhibitor of the PIP2‐IP3/DAG signal transduction pathway, abolished the stimulating effect of stressors, both in roots (retarding cytokinin synthesis) and consequently also in leaves (reducing cytokinin‐dependent chlorophyll accumulation). This suggests the involvement of the PIP2‐IP3/DAG signal transduction pathway in generation of these consecutive organ‐specific responses.
Calcyon is necessary for activity‐dependent AMPA receptor internalization and LTD in CA1 neurons of hippocampus
Authors: Davidson Heather Trantham , Xiao Jiping , Dai Rujuan , Bergson Clare 
Published: December 2008

AbstractCalcyon is a single transmembrane endocytic protein that regulates clathrin assembly and clathrin‐mediated endocytosis in the brain. Ultrastructural studies indicate that calcyon localizes to spines, but whether it regulates glutamate neurotransmission is not known. Here, we show that deletion of the calcyon gene in mice inhibits agonist‐stimulated endocytosis of α‐amino‐3‐hydroxy‐5‐methyl‐4‐isoxazolepropionic acid receptors (AMPARs), without altering basal surface levels of the GluR1 or GluR2 subunits. Whole‐cell patch‐clamp studies of hippocampal neurons in culture and CA1 synapses in slices revealed that knockout (KO) of calcyon abolishes long‐term synaptic depression (LTD), whereas mini‐analysis in slices indicated basal transmission in the hippocampus is unaffected by the deletion. Further, transfection of green fluorescent protein‐tagged calcyon rescued the ability of KO cultures to undergo LTD. In contrast, intracellular dialysis of a fusion protein containing the clathrin light‐chain‐binding domain of calcyon blocked the induction of LTD in wild‐type hippocampal slices. Taken together, the present studies involving biochemical, immunological and electrophysiological analyses raise the possibility that calcyon plays a specialized role in regulating activity‐dependent removal of synaptic AMPARs.
The Cotton Influence Index: An Examination of U.S. Cotton Subsidies
Authors: Gokcekus Omer , Fishler Richard 
Published: December 2008

AbstractGiven the lack of a bill or amendment specific to cotton, we introduce a Cotton Influence Index to capture legislators’ influence in championing the cause of the cotton growers during the hearings of the Farm Security and Rural Investment Act of 2002. Regression analyses reveal a relationship between Cotton Influence Index and campaign contributions, cotton farmland, party affiliation, and ideology. Tobit analysis indicates a significant relationship between different “actions and participations” by representatives to advance the interest of cotton—that is, components of this index and their future cotton political action committees’ (PACs) contributions to them.
Public Investment and Industry Incentives in Life‐Science Research
Authors: Wang Chenggang , Xia Yin , Buccola Steven 
Published: December 2008

AbstractLife‐science research has shifted rapidly from the public to the private sector, raising questions about government's remaining role. We shed light on the issue by employing a dynamic investment‐response model to examine the public's impact on industry life‐science research effort and success. We find that government expenditures in both basic biological research and agricultural and medical science create substantial spillovers for private firms. The spillovers are, unfortunately, partly nullified by government competition for scarce research inputs. Yet even after accounting for such competition, public investment has been strongly complementary to private investment. Indeed, opportunities created through public research are the principal source of growth in industry life sciences.
Physical and digital proximity: emerging ways of health care in face‐to‐face and telemonitoring of heart‐failure patients
Authors: Oudshoorn Nelly 
Published: December 2008

AbstractThe introduction of telehealth‐care technologies profoundly changes existing practices of care. This paper aims to enhance our understanding of these changes by providing a comparative study of health‐care services for heart‐failure patients based on face‐to‐face contacts in a policlinic (department of a health care facility treating outpatients) and remote consultations at a telehealth‐care centre. I will show how changes that take place when care moves from physical to virtual clinical encounters cannot be understood in terms of a replication of existing health‐care services. Instead, it is more useful to conceptualise these health‐care provisions as practices that create and value other kinds of care, incorporating different forms of proximity to patients. The physical proximity created at the policlinic facilitates contextualised, personalised care in which responsibilities for monitoring are delegated to nurses and patients and heart failure is constituted as an illness. The digital proximity that characterises the telehealth‐care centre supports individualised, immediate care in which responsibilities are largely delegated to technological devices and heart failure is constituted as a disease. A major policy implication of these differences is that telehealth‐care cannot simply replace physical consultations without changing the nature of health care.