bluuebunny/crossref_metadata_2025 huggingface dataset:
Enhanced Formation of Azoxymethane‐induced Colorectal Adenocarcinoma in γδ T Lymphocyte‐deficient Mice
Authors: Matsuda Shunji , Kudoh Shiori , Katayama Shouichi
Published: August 2005

T cell receptor (TCR) γδ ‐positive T lymphocytes, which are localized mostly within the intraepithe‐lial space of intestinal epithelium, have been suggested to play a role in maintaining the normal configuration of intestinal epithelium. However, the role of TCRγδ ‐positive T lymphocytes in the formation and progression of colorectal adenocarcinoma that originates from colorectal epithelial cells remains to be elucidated. In this study, TCRαβ and TCRγδ ‐positive T lymphocyte‐deficient mice (homozygous TCRα and TCRδ‐gene knockout mice) and the background wild‐type mice were administered azoxymethane, and the formation of macroscopic tumors and microscopic aberrant crypt foci in colorectal mucosa were compared among the three types of mice. Well‐differentiated adenocarcinoma appeared 5 months after 5 administrations of azoxymethane (10 mg/kg weight) only in a few TCRδ‐gene knockout mice and the frequency of the carcinoma‐bearing mice was increased at 7 and 9 months after the administration. Aberrant crypt foci were also detected in the colorectal mucosa of TCRδ‐gene knockout mice to a greater extent than in colorectal mucosa of TCRδ‐gene knockout mice 1 month after the azoxymethane administration. These results suggest that TCRγδ ‐positive T lymphocytes, which are present mainly in the intraepithelial space, play a role in suppression of the formation and progression of colorectal adenocarcinoma in mice.
Reversing Effect of Agosterol A, a Spongean Sterol Acetate, on Multidrug Resistance in Human Carcinoma Cells
Authors: Aoki Shunji , Chen Zhe‐Sheng , Higasiyama Kimihiko , Setiawan I , Akiyama Shin‐ichi , Kobayashi Motomasa
Published: August 2005

The effect of agosterol A, a novel polyhydroxylated sterol acetate isolated from a marine sponge, on P‐glycoprotein (P‐gp)‐mediated multidrug‐resistant cells (KB‐C2) and the multidrug resistance associated protein (MRPl)‐mediated multidrug‐resistant cells (KB‐CV60) was examined. Agosterol A reversed the resistance to colchicine in KB‐C2 cells and also the resistance to vincristine in KB‐CV60 cells at 3 to 10μMconcentration. Agosterol A at 3μMincreased the vincristine concentration in both KB‐C2 cells and KB‐CV60 cells to the level in parental KB‐3‐1 cells. Agosterol A also decreased the efflux of vincristine from both KB‐C2 cells and KB‐CV60 cells to the level seen in KB‐3‐1 cells. Agosterol A inhibited the [3H]azidopine‐photolabeling of P‐gp and also inhibited the uptake of [3H]S‐(2,4‐dinitrophenyl)glutathione (DNP‐SG) in inside‐out membrane vesicles prepared from KB‐CV60 cells. We conclude that agosterol A directly inhibited drug efflux through P‐gp and/or MRP1.
Simultaneous Intraluminal Thermobrachytherapy: An in vitro Study
Authors: Furuta Masaya , Tsukiyama Iwao , Kano Yasuhiko
Published: August 2005

A multi‐institutional study on simultaneous intraluminal thermobrachytherapy (SITB) for advanced esophageal cancer was conducted in Japan. In this study, brachytherapy was administered by a small radioactive source stepping through a catheter in the esophagus, and hyperthermia was also applied by an endoesophageal coil. However, experimental or clinical findings on the spatial distribution of its antitumor effects around the esophagus are not available. Therefore, we developed an in vitro model of SITB using a high‐dose‐rate iridium‐192 stepping source and two human cancer cell lines (WiDr and A549), and determined the spatial distribution of the antitumor effects. According to this model, the antitumor effects steeply decreased as the source‐cell distance increased when cells of both cell lines were irradiated with 5 Gy without heat. When WiDr cells, a more resistant cell line to radiation and heat, were simultaneously irradiated and heated for 30 min at 44°C, the effects decreased much less steeply as the distance increased. For A549 cells, a more sensitive cell line, irradiation with hyperthermia even at 42°C made the decrease in the effects smaller. The largest antitumor effects can be expected at 5‐10 mm beneath the esophageal mucosa, where the endoesophageal coil can heat tissues most effectively. SITE can induce larger antitumor effects than brachytherapy alone, especially in submucosal disease, which would favor treatment of advanced cancer.
QTL mapping for teat number in an Iberian‐by‐Meishan pig intercross
Authors: Rodríguez C. , Tomás A. , Alves E. , Ramirez O. , Arqué M. , Muñoz G. , Barragán C. , Varona L. , Silió L. , Amills M. , Noguera J. L.
Published: August 2005

The aim of this study was to investigate chromosomal regions affecting the number of teats in pigs and possible epistatic interactions between the identified quantitative trait loci (QTL). An experimental F2 cross between Iberian and Chinese Meishan lines was used for this purpose. A genomic scan was conducted with 117 markers covering the 18 porcine autosomes. Linkage analyses were performed by interval mapping using an animal model to estimate QTL and additive polygenic effects. Complementary analyses with models fitting two QTL were also carried out. The results showed three genomewide significant QTL mapping on chromosomes 5, 10 and 12, whose joint action control up to 30% of the phenotypic variance of the trait. Meishan alleles had a positive additive effect on teat number, and a positive‐additive × additive‐epistatic interaction was detected between QTL on chromosomes 10 and 12.
Genomic structure and gene order of swine chromosome 7q1.1→q1.2
Authors: Tanaka M. , Suzuki K. , Morozumi T. , Kobayashi E. , Matsumoto T. , Domukai M. , Eguchi‐Ogawa T. , Shinkai H. , Awata T. , Uenishi H.
Published: August 2005

To clarify the structure of the porcine genomic region that contains quantitative trait loci (QTL) related to fat, we constructed a bacterial artificial chromosome (BAC) contig of the region from DST to SRPK1 on porcine chromosome 7 and performed low‐redundancy ‘skim’ shotgun sequencing of the clones that composed a minimum tiling path of the contig. This analysis revealed that the gene order from VPS52 to SRPK1 is conserved between human and swine and that comparison with the human sequence identified a rearrangement in the swine genome at the proximal end of VPS52. Analysis of the nucleotide sequences of three BAC clones that included the rearrangement point demonstrated that COL21A1 and DST, which were not present in the corresponding human region, were located adjacent to the rearrangement point. These results provide useful information about the genomic region containing QTL for fat in pigs and help to clarify the structure of the so‐called ‘extended‐class II’ region distal to the porcine major histocompatibility complex class II region.
The ecdysteroidogenic P450 Cyp302a1/disembodied from the silkworm, Bombyx mori, is transcriptionally regulated by prothoracicotropic hormone
Authors: Niwa R. , Sakudoh T. , Namiki T. , Saida K. , Fujimoto Y. , Kataoka H.
Published: August 2005

During larval and pupal development of insects, ecdysone is synthesized in the prothoracic gland (PG). Although several Drosophila genes, including Halloween P450 genes, are known to be important for ecdysteroidogenesis in PG, little is known of the ecdysteroidogenic genes in other insects. Here we report on Cyp302a1/disembodied (dib‐Bm), one of the Halloween P450s in the silkworm Bombyx mori that is a carbon‐22 hydroxylase. dib‐Bm is predominantly expressed in PG and its developmental expression profile is correlated with a change in the ecdysteroid titre in the haemolymph. Furthermore, dib‐Bm expression in cultured PGs is significantly induced by treatment with prothoracicotropic hormone. This is the first report on the transcriptional induction of a steroidogenic gene by the tropic hormone in insects.
Plasticity in amino acid sensing of the chimeric receptor Taz
Authors: Michalodimitrakis Konstantinos M. , Sourjik Victor , Serrano Luis
Published: August 2005

Taz is a chimeric receptor consisting of the periplasmic, transmembrane and most of the HAMP linker domains of the Escherichia coli aspartate receptor (TarEc) and the cytoplasmic signalling domain of the E. coli osmosensor EnvZ. Aspartate is one of several attractant ligands normally sensed by Tar and it interacts with Taz to induce OmpR‐dependent transcription from the ompC promoter – albeit with reduced sensitivity relative to the chemotactic response it evokes via Tar. By combining Taz with a reporter system that expresses green fluorescent protein (GFP) from the ompC promoter, we were able to examine the interaction of Taz with all 20 natural amino acids. Some amino acids (Leu, Met, Val and Ser) reduced GFP expression, which in the case of leucine is likely attributed to a direct effect on the receptor, rather than an indirect effect through the leucine responsive protein (Lrp). Surprisingly, amino acids like Met and Ser – which are also attractants for Tar –‘inhibited’ Taz. Moreover, Taz exhibits a higher sensitivity to Leu compared with Asp, which is the inverse of Tar. Our results show the exquisite sensitivity of chemotactic receptors. Small conformational changes induced by making the chimera may have changed the way it responds to different amino acids.
Microscopic calcite dendrites in cold‐water tufa: implications for nucleation of micrite and cement
Authors: TURNER ELIZABETH C. , JONES BRIAN
Published: August 2005

Dendritic calcite forms in an active cold‐water tufa system in association with extracellular polymeric substances (EPS) that discontinuously coat bryophytes and cyanobacteria. Dendrites consist of 100–200 nm thick calcite fibres that form 3D lattice‐like domains. In each dendrite domain, fibres have three structurally equal orientations, which correspond in disposition to radii from the centre of a calcite unit cell to the convex triple face junctions on its surface. Fibres do not form in the orientation of the c‐axis. The external form of each dendrite has the shape of half of a shortened octahedron, with an upper triangular surface parallel to the substrate. Dendrite nucleation takes place on or in microbial EPS, whether microbial cells are present or not, and is probably effected by attraction of Ca2+ cations to negatively charged EPS, together with CO2‐degassing and concomitant pH increase of supersaturated spring water in stream splash zones. Ensuing dendrite growth is abiogenic and controlled by diffusion. Dendrite c‐axes are perpendicular to the substrate, probably because the negative charge of EPS forces the orientation of Ca2+ and CO planes within the developing dendrite crystal to be parallel to the EPS film surface. Dendrites are eventually filled and overgrown by solid, syntaxial calcite, which gradually and completely obliterates the dendrites as more familiar calcite crystal forms develop. No trace of the dendritic nucleus remains in the rock record. Calcite crystal nucleation may take place by this mechanism in many marine and meteoric settings, given that microbial EPS is now assumed to be virtually ubiquitous in these environments. This phenomenon could contribute to the development of familiar fabrics such as marine micrite cement and fibrous calcite cement, radial ooids, peloids, ‘abiogenic’ stromatolites, sea floor precipitates, microbialites, tufa, travertine, speleothems, and some meteoric cements. It may also contribute to the substrate‐normal orientation of c‐axes of common cement fabrics.
Nitric oxide is required for, and promotes auxin‐mediated activation of, cell division and embryogenic cell formation but does not influence cell cycle progression in alfalfa cell cultures
Authors: Ötvös Krisztina , Pasternak Taras P. , Miskolczi Pál , Domoki Mónika , Dorjgotov Dulguun , Sz˝cs Attila , Bottka Sándor , Dudits Dénes , Fehér Attila
Published: August 2005

It is now well established that nitric oxide (NO) serves as a signaling molecule in plant cells. In this paper experimental data are presented which indicate that NO can stimulate the activation of cell division and embryogenic cell formation in leaf protoplast‐derived cells of alfalfa in the presence of auxin. It was found that various NO‐releasing compounds promoted auxin‐dependent division (as shown by incorporation of bromodeoxyuridine) of leaf protoplast‐derived alfalfa cells. In contrast, application of NO scavenger or NO synthesis inhibitor inhibited the same process. Both the promotion and the inhibition of cell cycle activation correlated with the amount and activity of the cognate alfalfa p34cdc2 protein Medsa;CDKA;1,2. The effect of l‐NG‐monomethyl‐l‐arginine (l‐NMMA) was transient, and protoplast‐derived cells spending more than 3 days in culture become insensitive to the inhibitor as far as cell cycle progression was concerned. l‐NMMA had no effect on the cell cycle parameters of cycling suspension‐cultured cells, but had a moderate transient inhibitory effect on cells re‐entering the cell cycle following phosphate starvation. Cycling cultured cells, however, could respond to NO, as indicated by the sodium nitroprusside (SNP)‐ and 2‐phenyl‐4,4,5,5‐tetramethylimidazoline‐1‐oxyl‐3‐oxide (PTIO)‐dependent accumulation of the ferritin protein. Based on these observations, it is hypothesized that l‐NMMA‐sensitive generation of NO is involved in the activation, but not the progression of the plant cell division cycle. In addition, SNP promoted and l‐NMMA delayed the exogenous auxin [2,4‐dichlorophenoxyacetic acid (2,4‐D)] concentration‐dependent formation of embryogenic cell clusters expressing the MsSERK1 gene; this further supports a link between auxin‐ and NO‐dependent signaling pathways in plant cells.
Outcrossing hermaphroditic polychaete worms adjust their sex allocation to social conditions
Authors: LORENZI M. C. , SELLA G. , SCHLEICHEROVÁ D. , RAMELLA L.
Published: August 2005

Sex allocation theory predicts that simultaneous hermaphrodites shift sex allocation facultatively in response to variation in local group size. This study was performed to evaluate the relative investment in each sex function by the simultaneously hermaphroditic polychaete worm Ophryotrocha diadema and to test whether allocation to each sex depends on the number of reproductive competitors. Four experimental groups were set up (in a 2 × 2 factorial design) with small or large group size and with small or large enclosures to control for potential confounding effects of density. We measured the proportion of female and male investment in focal individuals. Results revealed that individuals regulated their reproductive output so that when reproductive competitors were present, the number of female gametes was strongly reduced and the male function increased. In contrast, under monogamy, individuals in small groups produced lower numbers of sperm but had a higher egg output than worms in large groups. Density did not affect sex allocation in our experiment. Our findings provide qualitative support for Local Mate Competition theory, but also show that the pattern of sex allocation specific to this species is more complex than expected by current theory.
Remating in Drosophila melanogaster: an examination of the trading‐up and intrinsic male‐quality hypotheses
Authors: BYRNE P. G. , RICE W. R.
Published: August 2005

Female Drosophila melanogaster remate more frequently than necessary to ensure fertilization. We tested whether polyandrous females gain genetic benefits for their offspring by (1) selecting secondary sires of higher genetic‐quality than original partners or (2) because post‐copulatory mechanisms bias fertilizations towards genetically superior males. We screened 119 hemiclones of males for lifetime fitness then selected eight hemiclones (four of extreme high fitness and four of extreme low fitness) and mated them to virgin females. Females were then given the opportunity to remate with males of benchmark‐genetic quality and their propensity to remate (fidelity) and sperm displacement scored. A female's fidelity and her level of sperm displacement varied depending on which hemiclone she mated first, but not on male‐genetic quality. These findings indicate that female remating and sperm displacement are strongly influenced by male genotype, but provide no evidence that these traits contribute to adaptive female choice to obtain superior genes for offspring.
Sexy sons from re‐mating do not recoup the direct costs of harmful male interactions in the Drosophila melanogaster laboratory model system
Authors: ORTEIZA N. , LINDER J. E. , RICE W. R.
Published: August 2005

The empirical foundation for sexual conflict theory is the data from many different taxa demonstrating that females are harmed while interacting with males. However, the interpretation of this keystone evidence has been challenged because females may more than counterbalance the direct costs of interacting with males by the indirect benefits of obtaining higher quality genes for their offspring. A quantification of this trade‐off is critical to resolve the controversy and is presented here. A multi‐generation fitness assay in the Drosophila melanogaster laboratory model system was used to quantify both the direct costs to females due to interactions with males and indirect benefits via sexy sons. We specifically focus on the interactions that occur between males and nonvirgin females. In the laboratory environment of our base population, females mate soon after eclosion and store sufficient sperm for their entire lifetime, yet males persistently court these nonvirgin females and frequently succeed in re‐mating them. Females may benefit from these interactions despite direct costs to their lifetime fecundity if re‐mating allows them to trade‐up to mates of higher genetic quality and thereby secure indirect benefits for their offspring. We found that direct costs of interactions between males and nonvirgin females substantially exceeded indirect benefits through sexy sons. These data, in combination with past studies of the good genes route of indirect benefits, demonstrate that inter‐sexual interactions drive sexually antagonistic co‐evolution in this model system.
Molecular evolution of animal antimicrobial peptides: widespread moderate positive selection
Authors: TENNESSEN J. A.
Published: August 2005

An increasing number of studies in both vertebrates and invertebrates show that the evolution of antimicrobial peptides is driven by positive selection. Because these diverse molecules show potential for therapeutic applications, they are currently the targets of much structural and functional research, providing extensive background data for evolutionary studies. In this paper, patterns of molecular evolution in antimicrobial peptide genes are reviewed. Evidence for positive selection on antimicrobial peptides includes an excess of nonsynonymous nucleotide substitutions, an excess of charge‐changing amino acid substitutions, nonneutral patterns of allelic variation, and functional assays in vivo and in vitro that show improved antimicrobial effects for derived sequence variants. Positive selection on antimicrobial peptides may be as common as, but perhaps weaker than, selection on the best‐known example of adaptively evolving immunity genes, the major histocompatibility complex. Thus, antimicrobial peptides present a useful and underutilized model for the study of adaptive molecular evolution.
Adaptive radiation in microbial microcosms
Authors: CRAIG MACLEAN R.
Published: August 2005

It has often been argued that evolutionary diversification is the result of divergent natural selection for specialization on alternative resources. I provide a comprehensive review of experiments that examine the ecology and genetics of resource specialization and adaptive radiation in microbial microcosms. In these experiments, resource heterogeneity generates divergent selection for specialization on alternative resources. At a molecular level, the evolution of specialization is generally attributable to mutations that de‐regulate the expression of existing biosynthetic and catabolic pathways. Trade‐offs are associated with the evolution of resource specialization, but these trade‐offs are often not the result of antagonistic pleiotropy. Replicate adaptive radiations result in the evolution of a similar assemblage of specialists, but the genetic basis of specialization differs in replicate radiations. The implications of microbial selection experiments for evolutionary theory are discussed and future directions of research are proposed.
Extreme mtDNA divergences in a terrestrial slug (Gastropoda, Pulmonata, Arionidae): accelerated evolution, allopatric divergence and secondary contact
Authors: PINCEEL J. , JORDAENS K. , BACKELJAU T.
Published: August 2005

Extremely high levels of intraspecific mtDNA differences in pulmonate gastropods have been reported repeatedly and several hypotheses to explain them have been postulated. We studied the phylogeny and phylogeography of 51 populations (n = 843) of the highly polymorphic terrestrial slug Arion subfuscus (Draparnaud, 1805) across its native distribution range in Western Europe. By combining the analysis of single stranded conformation polymorphisms (SSCP) and nucleotide sequencing, we obtained individual sequence data for a fragment of the mitochondrial 16S rDNA and a fragment of the nuclear ITS1. Additionally, five polymorphic allozyme loci were scored. Based on the 16S rDNA phylogeny, five monophyletic haplotype groups with sequence divergences of 9–21% were found. Despite this deep mitochondrial divergence, the haplotype groups were not monophyletic for the nuclear ITS1 fragment and haplotype group‐specific allozyme alleles were not found. Although there is evidence for an accelerated mtDNA clock, the divergence among the haplotype groups is older than the Pleistocene and their current allopatric ranges probably reflect allopatric divergence and glacial survival in separate refugia from which different post‐glacial colonization routes were established. A range‐overlap of two mtDNA groups (S1 and S2, 21% sequence divergence) stretched from Central France and Belgium up to the North of the British Isles. The nuclear data suggest that this secondary contact resulted in hybridization between the allopatrically diverged groups. Therefore, it seems that, at least for two of the groups, the deep mtDNA divergence was only partially accompanied by the formation of reproductive isolation.
The importance of phylogenetic scale in tests of Bergmann's and Rapoport's rules: lessons from a clade of South American lizards
Authors: CRUZ F. B. , FITZGERALD L. A. , ESPINOZA R. E. , SCHULTE II J. A.
Published: August 2005

We tested for the occurrence of Bergmann's rule, the pattern of increasing body size with latitude, and Rapoport's rule, the positive relationship between geographical range size and latitude, in 34 lineages of Liolaemus lizards that occupy arid regions of the Andean foothills. We tested the climatic‐variability hypothesis (CVH) by examining the relationship between thermal tolerance breadth and distribution. Each of these analyses was performed varying the level of phylogenetic inclusiveness. Bergmann's rule and the CVH were supported, but Rapoport's rule was not. More variance in the data for Bergmann's rule and the CVH was explained using species belonging to the L. boulengeri series rather than all species, and inclusion of multiple outgroups tended to obscure these macroecological patterns. Evidence for Bergmann's rule and the predicted patterns from the CVH remained after application of phylogenetic comparative methods, indicating a greater role of ecological processes rather than phylogeny in shaping the current species distributions of these lizards.
Evolutionary dynamics and population biology of a polymorphic insect
Authors: SVENSSON E. I. , ABBOTT J.
Published: August 2005

Conspicuous heritable polymorphisms are useful to address the question if morph frequencies are stable or whether they fluctuate between generations. Ecological geneticists have studied colour polymorphisms in the past, but there are few long‐term studies of genetic dynamics across multiple generations. We studied morph‐frequency dynamics and female fecundity in the trimorphic blue‐tailed damselfly (Ischnura elegans). The morphs include a male‐coloured (androchrome) type of female, which is thought to be maintained by frequency‐dependent sexual conflict. Morph frequencies changed significantly between years across all populations. There was evidence for directional frequency change since androchrome females increased in 9 of 10 populations across a 4‐year period. There was heterogeneity between populations in their evolutionary trajectories, partly caused by population age: androchrome frequencies were initially high in young populations but gradually decreased and approached the level of old populations. We discuss the possible causes of morph‐frequency fluctuations, and the role of morph‐specific fecundity, dispersal and other forces influencing evolutionary dynamics in this system.
Does egg competition occur in marine broadcast‐spawners?
Authors: MARSHALL D. J. , EVANS J. P.
Published: August 2005

When the availability of sperm limits female reproductive success, competition for sperm, may be an important broker of sexual selection. This is because sperm limitation can increase the variance in female reproductive success, resulting in strong selection on females to compete for limited fertilization opportunities. Sperm limitation is probably common in broadcast‐spawning marine invertebrates, making these excellent candidates for investigating scramble competition between broods of eggs and its consequences for female reproductive success. Here, we report our findings from a series of experiments that investigate egg competition in the sessile, broadcast‐spawning polychaete Galeolaria caespitosa. We initially tested whether the order in which eggs encounter sperm affects their fertilization success at two ecologically relevant current regimes. We used a split‐clutch—split‐ejaculate technique to compare the fertilization success of eggs from individual females that had either first access (competition‐free treatment) or second access (egg competition treatment) to a batch of sperm. We found that fertilization success depended on the order in which eggs accessed sperm; eggs that were assigned to the competition‐free treatment exhibited significantly higher fertilization rates than those assigned to the egg competition treatment at both current speeds. In subsequent experiments we found that prior exposure of sperm to eggs significantly reduced both the quantity and quality of sperm available to fertilize a second clutch of eggs, resulting in reductions in fertilization success at high and low sperm concentrations. These findings suggest that female traits that increase the likelihood of sperm‐egg interactions (e.g. egg size) will respond to selection imposed by egg competition.
Maternal genetic effects on adaptive divergence between anadromous and resident brook charr during early life history
Authors: PERRY G. M. L. , AUDET C. , BERNATCHEZ L.
Published: August 2005

The importance of directional selection relative to neutral evolution may be determined by comparing quantitative genetic variation in phenotype (QST) to variation at neutral molecular markers (FST). Quantitative divergence between salmonid life history types is often considerable, but ontogenetic changes in the significance of major sources of genetic variance during post‐hatch development suggest that selective differentiation varies by developmental stage. In this study, we tested the hypothesis that maternal genetic differentiation between anadromous and resident brook charr (Salvelinus fontinalisMitchill) populations for early quantitative traits (embryonic size/growth, survival, egg number and developmental time) would be greater than neutral genetic differentiation, but that the maternal genetic basis for differentiation would be higher for pre‐resorption traits than post‐resorption traits. Quantitative genetic divergence between anadromous (seawater migratory) and resident Laval River (Québec) brook charr based on maternal genetic variance was high (QST > 0.4) for embryonic length, yolk sac volume, embryonic growth rate and time to first response to feeding relative to neutral genetic differentiation [FST = 0.153 (0.071–0.214)], with anadromous females having positive genetic coefficients for all of the above characters. However,QSTwas essentially zero for all traits post‐resorption of the yolk sac. Our results indicate that the observed divergence between resident and anadromous brook charr has been driven by directional selection, and may therefore be adaptive. Moreover, they provide among the first evidence that the relative importance of selective differentiation may be highly context‐specific, and varies by genetic contributions to phenotype by parental sex at specific points in offspring ontogeny. This in turn suggests that interpretations ofQST‐FSTcomparisons may be improved by considering the structure of quantitative genetic architecture by age category and the sex of the parent used in estimation.
Reproductive ageing and sexual selection on male body size in a wild population of antler flies (Protopiophila litigata)
Authors: BONDURIANSKY R. , BRASSIL C. E.
Published: August 2005

Little is known about the importance of trade‐offs between ageing and other life history traits, or the effects of ageing on sexual selection, particularly in wild populations suffering high extrinsic mortality rates. Life history theory suggests that trade‐offs between reproduction and somatic maintenance may constrain individuals with higher initial reproductive rates to deteriorate more rapidly, resulting in reduced sexual selection strength. However, this trade‐off may be masked by increased condition dependence of reproductive effort in older individuals. We tested for this trade‐off in males in a wild population of antler flies (Protopiophila litigata). High mating rate was associated with reduced longevity, as a result of increased short‐term mortality risk or accelerated ageing in traits affecting viability. In contrast, large body size was associated with accelerated ageing in traits affecting mating success, resulting in reduced sexual selection for large body size. Thus, ageing can affect sexual selection and evolution in wild populations.
The evolution of fledging age in songbirds
Authors: ROFF D. A. , REMEŠ V. , MARTIN T. E.
Published: August 2005

In birds with altricial young an important stage in the life history is the age at fledging. In this paper we use an approach proven successful in the prediction of the optimal age at maturity in fish and reptiles to predict the optimal age of fledging in passerines. Integrating the effects of growth on future fecundity and survival leads to the prediction that the optimal age at fledging is given by a function that comprises survival to maturity, the exponent of the fecundity‐body size relationship and nestling growth. Growth is described by the logistic equation with parameters,A, Kandti. Assuming that the transitional mortality curve can be approximated by the nestling mortality,Mn, the optimal fledging age,tf, is given by a simple formula involving the three growth parameters, nestling mortality (Mn) and the exponent (d) of the fecundity‐body size relationship. Predictions of this equation underestimate the true values by 11–16%, which is expected as a consequence of the transitional mortality function approximation. A transitional mortality function in which mortality is approximately 0.3–0.4 of nesting mortality (i.e. mortality declines rapidly after fledging) produces predictions which, on average, equal the observed values. Data are presented showing that mortality does indeed decline rapidly upon fledging.
Changes in genetic architecture during relaxation in Drosophila melanogaster selected on divergent virgin life span
Authors: Vermeulen C. J. , Bijlsma R.
Published: August 2005

Artificial selection experiments often confer important information on the genetic correlations constraining the evolution of life history. After artificial selection has ceased however, selection pressures in the culture environment can change the correlation matrix again. Here, we reinvestigate direct and correlated responses in a set of lines of Drosophila melanogaster that were selected on virgin life span and for which selection has been relaxed for 10 years. The decrease in progeny production in long-lived lines, a strong indication of antagonistic pleiotropy, had disappeared during relaxation. This was associated with a higher cost of reproduction to long-lived flies in mated, but not in virgin life span. These data strongly suggest that genetic mechanisms of mated and virgin life span determination are partly independent. Furthermore, data on body weight, developmental time and viability indicated deleterious effects of longevity selection in either direction, giving rise to a nonlinear relationship with life span for these characters. In order to reclaim original patterns, we founded a new set of derived lines by resuming selection in mixed replicate lines of the original set. Although selection was successful, most patterns in correlated characters remained, showing that these new patterns are resistant to new episodes of selection.
The effect of female polyandry and sperm precedence on the evolution of sexual difference in dispersal timing
Authors: HIROTA T.
Published: August 2005

Predispersal copulation and unpredictable environment facilitate the evolution of female‐biased dispersal in species, where females are functionally monandrous. Females should migrate and reproduce over different habitats to spread their risks due to environmental fluctuation. On the other hand, males do not have to disperse because their risks are spread by their mating partners who produce their offspring in different habitats. However, when females are functionally polyandrous, it is expected that they will not contribute to spreading the male's risk extensively. Therefore, by simulation with the individual based model, the present study evaluated how female polyandry influences the sexual difference in dispersal timing. This model revealed that when females are polyandrous, the timing of female remating and sperm priority patterns have an important influence on the evolution of sex‐biased dispersal. Particularly when female remating is not synchronized with dispersal or when last‐male sperm precedence does not exist, female‐biased dispersal is evolved.
Geographical patterns of adaptation within a species’ range: interactions between drift and gene flow
Authors: Alleaume-benharira M. , Pen I. R. , Ronce O.
Published: August 2005

We use individual-based stochastic simulations and analytical deterministic predictions to investigate the interaction between drift, natural selection and gene flow on the patterns of local adaptation across a fragmented species’ range under clinally varying selection. Migration between populations follows a stepping-stone pattern and density decreases from the centre to the periphery of the range. Increased migration worsens gene swamping in small marginal populations but mitigates the effect of drift by replenishing genetic variance and helping purge deleterious mutations. Contrary to the deterministic prediction that increased connectivity within the range always inhibits local adaptation, simulations show that low intermediate migration rates improve fitness in marginal populations and attenuate fitness heterogeneity across the range. Such migration rates are optimal in that they maximize the total mean fitness at the scale of the range. Optimal migration rates increase with shallower environmental gradients, smaller marginal populations and higher mutation rates affecting fitness.
Yolk androgens in the barn swallow (Hirundo rustica): a test of some adaptive hypotheses
Authors: Gil D. , Ninni P. , Lacroix A. , De Lope F. , Tirard C. , Marzal A. , Pape MøLler A.
Published: August 2005

Maternal effects such as androgen in avian eggs can mediate evolutionary responses to selection, allowing manipulation of offspring phenotype and promoting trans-generational adaptive effects. We tested the predictions of two adaptive hypotheses that have been proposed to explain female variation in yolk androgen allocation in birds, using the barn swallow Hirundo rustica as a model. We found no support for the first hypothesis proposing that yolk androgen varies as a function of breeding density in order to prepare offspring for different breeding densities. However, we found experimental support for the hypothesis that female yolk androgen allocation depends on mate attractiveness and that it constitutes an example of differential allocation. Females increased the concentration of androgens in their eggs when mated to males with experimentally elongated tails. Female phenotypic quality as measured by arrival date and clutch size was positively related to egg androgen concentration, consistent with the hypothesis that this is a costly investment, constrained by female condition. We found correlative evidence of a direct relationship between egg androgen concentration and performance of offspring as measured by mass increase.
Analysis of microsatellite variation in Pinus radiata reveals effects of genetic drift but no recent bottlenecks
Authors: Karhu A. , Vogl C. , Moran G. F. , Bell J. C. , Savolainen O.
Published: August 2005

Most conifer species occur in large continuous populations, but radiata pine, Pinus radiata, occurs only in five disjunctive natural populations in California and Mexico. The Mexican island populations were presumably colonized from the mainland millions of years ago. According to Axelrod (1981), the mainland populations are relicts of an earlier much wider distribution, reduced some 8000 years ago, whereas according to Millar (1997, 2000), the patchy metapopulation-like structure is typical of the long-term population demography of the species. We used 19 highly polymorphic microsatellite loci to describe population structure and to search for signs of the dynamics of population demography over space and time. Frequencies of null alleles at microsatellite loci were estimated using an approach based on the probability of identity by descent. Microsatellite genetic diversities were high in all populations [expected heterozygosity (He) = 0.68–0.77], but the island populations had significantly lower estimates. Variation between loci in genetic differentiation (FST) was high, but no locus deviated statistically significantly from the rest at an experiment wide level of 0.05. Thus, all loci were included in subsequent analysis. The average differentiation was measured as FST = 0.14 (SD 0.012), comparable with earlier allozyme results. The island populations were more diverged from the other populations and from an inferred common ancestral gene pool than the mainland ones. All populations showed a deficiency of expected heterozygosity given the number of alleles, the mainland populations more so than the island ones. The results thus do not support a recent important contraction in the mainland range of radiata pine.
Cophylogenetic relationships between penguins and their chewing lice
Authors: Banks J. C. , Palma R. L. , Paterson A. M.
Published: August 2005

It is generally thought that the evolution of obligate parasites should be linked intimately to the evolution of their hosts and that speciation by the hosts should cause speciation of their parasites. The penguins and their chewing lice present a rare opportunity to examine codivergence between a complete host order and its parasitic lice. We estimated a phylogeny for all 15 species of lice parasitising all 17 species of penguins from the third domain of the mitochondrial 12S ribosomal rRNA gene, a portion of the mitochondrial cytochrome oxidase subunit 1 gene and 55 morphological characters. We found no evidence of extensive cospeciation between penguins and their chewing lice using TreeMap 2.02β. Despite the paucity of cospeciation, there is support for significant congruence between the louse and penguin phylogenies due to possible failure to speciate events (parasites not speciating in response to their hosts speciating).
Measuring natural and sexual selection on breeding values of male display traits in Drosophila serrata
Authors: Skroblin A. , Blows M.W.
Published: August 2005

Fundamental to many theories of sexual selection is the expectation that sexual traits, which males use in an attempt to increase mating success, confer costs as well as benefits to individual males. Although evolution of exaggerated male traits is predicted to be halted, by costs applied by natural selection, there is a lack of empirical work devoted to quantitatively establishing whether natural selection opposes sexual selection generated by the preferences of females. In this study, we quantified natural and sexual selection gradients on breeding values for cuticular hydrocarbon (CHC) components of male contact pheromones in Drosophila serrata. As male sexual traits may often be environmentally condition dependent, breeding values were used in the selection analysis to remove the possibility of environmental correlations between the measured trait and fitness biasing estimates of selection. The direction of natural selection was found to oppose sexual selection on a subset of CHCs examined. Opposing natural and sexual selection suggests that further evolution of the male pheromone may in part be limited by costs associated with attractive male CHC blends.
An Epidemiological Study of Headache in Florianopolis, Brazil
Authors: Queiroz LP , Barea LM , Blank N
Published: August 2005

The aim of this study was to estimate the 1-year prevalence of headache, migraine, tension-type headache (TTH) and chronic daily headache (CDH), and the degree of association of migraine with some sociodemographic characteristics of the population of Florianopolis, Brazil. This is a cross-sectional, door-to-door, population-based study. In 300 randomly selected households, 625 subjects, aged 15–64 years, responded to a structured questionnaire. The 1-year prevalence of headache was 80.8%, of migraine 22.1%, of TTH 22.9%, and of CDH 6.4%. Migraine and CDH were significantly more prevalent in females than in males. Migraine was significantly associated with the following variables: low household income, low electricity consumption, and divorced or widowed marital status. We have shown high prevalences of migraine and CDH in Florianopolis, close to the higher rates of previous studies. There was a preponderance of migraine in females, divorced  or  widowed,  with  a  low  socioeconomic  level.
Behaviour During Attacks and Assessment of Intensity in Primary Headaches of Children and Adolescents
Authors: Rossi LN , Cortinovis I , Menegazzo L , Menini S , Carnelli V
Published: August 2005

Assessment of attack intensity in primary headaches of paediatric age has not received great attention in the literature to date and in the international classification the criteria to define pain intensity are also not specified. The purpose of this research was to evaluate whether behaviour during attacks, reported by the child or a parent, can be used as a measure of attack disability, and so as an indirect measure of attack intensity in primary headaches of children and adolescents. The subjects were 320 patients aged between 3 and 14 years (mean age 9.9 years, SD 2.6 years) affected by primary recurrent headaches and first seen at a headache clinic. Twelve variables taken from their history were considered and sequentially analysed with multiple correspondence analysis and cluster analysis. Five types of behaviour during attacks were identified: (i) the child (or the parent) is unable to answer the questions or the child has no limitation in activities; (ii) the child may have some activity limitation, but only in lively games; (iii) the child has limitations in daily life with regard also to quiet activities; (iv) at least during some attacks the child lies down with closed eyes or in the dark; (v) during each attack the child lies down with closed eyes or in the dark. The least important variables for the identification of the five behaviour types were studying at school and absence from school. There are some limitations in considering child's behaviour as a measure of attack intensity/disability; one of these is the fact that it was found to be related to the educational level of the mother. However, behaviour during attacks, reported by the child or the parent, provides useful information independently of child's age and, together with the score of pain, when this is given, it can be used as measure of attack  intensity.
Brainstem and Cervical Spinal Cord Fos Immunoreactivity Evoked by Nerve Growth Factor Injection into Neck Muscles in Mice
Authors: Panfil C , Makowska A , Ellrich J
Published: August 2005

Although myofascial tenderness is thought to play a key role in the pathophysiology of tension-type headache, very few studies have addressed neck muscle nociception. The neuronal activation pattern following local nerve growth factor (NGF) administration into semispinal neck muscles in anaesthetized mice was investigated using Fos protein immunohistochemistry. In order to differentiate between the effects of NGF administration on c-fos expression and the effects of surgical preparation, needle insertion and intramuscular injection, the experiments were conducted in three groups. In the sham group ( n = 7) cannula needles were only inserted without any injection. In the saline ( n = 7) and NGF groups ( n = 7) 0.9% physiological saline solution or 0.8 µM NGF solution were injected in both muscles, respectively. In comparison with sham and saline conditions, NGF administration induced significantly stronger Fos immunoreactivity in the mesencephalic periaqueductal grey (PAG), the medullary lateral reticular nucleus (LRN), and superficial layers I and II of cervical spinal dorsal horns C1, C2 and C3. This activation pattern corresponds very well to central nervous system processing of deep noxious input. A knowledge of the central anatomical representation of neck muscle pain is an essential prerequisite for the investigation of neck muscle nociception in order to develop a future model of tension-type headache.
Peripheral Levels of BDNF and NGF in Primary Headaches
Authors: Blandini F , Rinaldi L , Tassorelli C , Sances G , Motta M , Samuele A , Fancellu R , Nappi G , Leon A
Published: August 2005

Neurotrophins, such as brain-derived neurotrophic factor (BDNF) and nerve growth factor (NGF), have been implicated in the generation and modulation of pain. To investigate whether alterations in neurotrophin levels can be detected in subjects suffering from nociceptive disorders, such as primary headaches, we determined the peripheral (platelet and plasma) levels of BDNF and NGF in patients suffering from migraine, with or without aura, or cluster headache (CH), in the interictal phase, and in healthy volunteers. All primary headaches patients studied showed significantly decreased platelet levels of BDNF (migraine vs. controls P < 0.001; CH vs. controls P < 0.01), while a selective reduction of platelet NGF was observed in migraine sufferers and not in CH patients compared with control subjects (migraine vs. controls P < 0.001). These changes were not accompanied by significant modifications of neurotrophin plasma levels. Our findings show for the first time that changes in peripheral levels of neurotrophines (BDNF and NGF) occur in patients suffering from different types of primary headaches, suggesting a potential involvement of BDNF and NGF in the pathophysiology of these disorders, and raising the possibility that differences in peripheral neurotrophins may help to distinguish migraine biologically from CH.