bluuebunny/crossref_metadata_2025 huggingface dataset:
The anther smut disease on Gypsophila repens: a case of parasite sub‐optimal performance following a recent host shift?
Authors: LÓPEZ‐VILLAVICENCIO M. , ENJALBERT J. , HOOD M. E. , SHYKOFF J. A. , RAQUIN C. , GIRAUD T.
Published: August 2005

The study of how parasites adapt to new hosts is of great importance for understanding the emergence of new diseases. Here, we report a study of the anther smut disease on Gypsophila repens (Caryophyllaceae). In contrast to what is usually found on other host species, infected natural populations of G. repens are extremely rare. Moreover, symptoms of diseased plants are incomplete and highly variable over the time. These results suggest that the fungus infecting G. repens is a case of a parasite not capable of exploiting its host optimally. Molecular analyses of Microbotryum violaceum strains infecting this and other Caryophyllaceae revealed that this sub‐optimal behaviour probably resulted from a recent host shift from the morphologically similar plant Petrorhagia saxifraga. With its exceptionally low virulence and prevalence, but apparent self‐sustainability, the disease on G. repens may thus represent an interesting case study for investigating the conditions leading to adaptation of parasites on new hosts.
The evolution of male genitalia: patterns of genetic variation and covariation in the genital sclerites of the dung beetle Onthophagus taurus
Authors: HOUSE C. M. , SIMMONS L. W.
Published: August 2005

Three main hypotheses, have been invoked to explain divergent genital evolution, the lock and key, pleiotropy, and sexual selection hypotheses, each of which make different predictions about how genital traits are inherited. Here we used a half‐sib breeding design to examine the patterns of genetic variation and covariation between male genital sclerites, and their covariance with general body morphology in the dung beetle Onthophagus taurus. We found CVA's and CVP's were similar for both genital and general morphological traits and that CVR's were large for both trait types. We found that male genital sclerites were negatively genetically correlated with general morphological traits. Variation in male genital morphology has direct implications for a male's fertilization success and the resulting sexual selection acting on male genitalia is predicted to maintain high levels of additive genetic variance. Contrary to this prediction, we found that individual genital sclerites all had low levels of additive genetic variance and large maternal and environmental sources of variation. Our data suggest that the genital sclerites in O. taurus are not inherited independently but as a genetically integrated unit. More importantly, the way the different sclerites function to influence male fertilization success reflects this genetic integration. Even though levels of VA in individual genital sclerites may be low, there may still be sufficient VA in multivariate trait space for selection to generate evolutionary change in the overall morphology of male genitalia.
The social parasite waspPolistes atrimandibularisdoes not form host races
Authors: FANELLI D. , HENSHAW M. , CERVO R. , TURILLAZZI S. , QUELLER D. C. , STRASSMANN J. E.
Published: August 2005

Parasites that exploit the parental behaviour of several host species may be selected to form distinct host‐specific genetic lineages. This process is well documented in bird brood parasites, but not in insect social parasites.Polistes atrimandibularisis the only paper‐wasp social parasite known to exploit four host species. It does not form genetically distinct host races according to analyses based on microsatellite loci. Also, there were no size‐matching between parasites and host species. Instead,P. atrimandibularisqueens seemed to be successful as parasites in this population only when they originated from nests ofP. dominulus, the largest species. The other host species are a sink forP. atrimandibularissince adult females emerging from those nests appear too small to usurp colonies themselves. Traits that may helpP. atrimandibularisinfiltrate multiple species may include its nonaggressive usurpation tactics and its ability to acquire host cuticular hydrocarbon recognition labels.
On the worldwide spread of an insecticide resistance gene: a role for local selection
Authors: LABBE P. , LENORMAND T. , RAYMOND M.
Published: August 2005

Adaptation occurs by gene replacement (or transient balanced polymorphism). Replacement may be caused by selection (local or global) and/or genetic drift among alleles. In addition, historical events may blur the respective effects of selection and drift during the course of replacement. We address the relative importance of these processes in the evolution of insecticide resistance genes in the mosquito Culex pipiens. The resistance allele, Ester2, has a broad geographic distribution compared to the other resistance alleles. To distinguish between the different processes explaining this distribution, we reviewed the literature and analysed updated data from the Montpellier area of southern France. Overall, our data indicate that Ester2 prevails over other Ester resistance alleles in moderately treated areas. Such conditions are common and favour the hypothesis of selection acting at a local level. This places an emphasis on the importance of ecological conditions during the evolution of resistance. Finally, we highlight that historical events have contributed to its spread in some areas.
Influence of genotype‐temperature interaction on pollen performance
Authors: HEDHLY A. , HORMAZA J. I. , HERRERO M.
Published: August 2005

Pollen competition and selection have significant evolutionary consequences, but very little is known about how they can be modulated. We have examined in cherry (Prunus avium L.) how pollen performance is affected by the genotype of the pollen and by the environmental conditions under which it grows, namely the pistilar tissue and temperature. The different pollen donor genotypes tested in this work differed in their behaviour both in vitro and in vivo and this behaviour was modulated depending on the female recipient they grew on. Furthermore, there was a significant temperature‐genotype interaction that affected the pollen tube population census that succeeded in reaching the base of the style. The combination of these three factors, while enabling a capacity of response to variations in environmental pressures, could maintain variability in pollen performance avoiding the fixation of the genes that control pollen tube growth rate.
Interspecific variation in the use of carotenoid‐based coloration in birds: diet, life history and phylogeny
Authors: OLSON V. A. , OWENS I. P. F.
Published: August 2005

Birds show striking interspecific variation in their use of carotenoid‐based coloration. Theory predicts that the use of carotenoids for coloration is closely associated with the availability of carotenoids in the diet but, although this prediction has been supported in single‐species studies and those using small numbers of closely related species, there have been no broad‐scale quantitative tests of the link between carotenoid coloration and diet. Here we test for such a link using modern comparative methods, a database on 140 families of birds and two alternative avian phylogenies. We show that carotenoid pigmentation is more common in the bare parts (legs, bill and skin) than in plumage, and that yellow coloration is more common than red. We also show that there is no simple, general association between the availability of carotenoids in the diet and the overall use of carotenoid‐based coloration. However, when we look at plumage coloration separately from bare part coloration, we find there is a robust and significant association between diet and plumage coloration, but not between diet and bare part coloration. Similarly, when we look at yellow and red plumage colours separately, we find that the association between diet and coloration is typically stronger for red coloration than it is for yellow coloration. Finally, when we build multivariate models to explain variation in each type of carotenoid‐based coloration we find that a variety of life history and ecological factors are associated with different aspects of coloration, with dietary carotenoids only being a consistent significant factor in the case of variation in plumage. All of these results remain qualitatively unchanged irrespective of the phylogeny used in the analyses, although in some cases the precise life history and ecological variables included in the multivariate models do vary. Taken together, these results indicate that the predicted link between carotenoid coloration and diet is idiosyncratic rather than general, being strongest with respect to plumage colours and weakest for bare part coloration. We therefore suggest that, although the carotenoid‐based bird plumage may a good model for diet‐mediated signalling, the use of carotenoids in bare part pigmentation may have a very different functional basis and may be more strongly influenced by genetic and physiological mechanisms, which currently remain relatively understudied.
Games among cannibals: competition to cannibalize and parent‐offspring conflict lead to increased sibling cannibalism
Authors: PERRY J. C. , ROITBERG B. D.
Published: August 2005

Sibling cannibalism occurs in many species, yet understanding of sibling cannibalism as an adaptation currently lags behind understanding of other antagonistic interactions among siblings. Observed sibling cannibalism phenotypes likely reflect the interaction between competitive games among siblings and parent‐offspring conflict. Using a game‐theoretic approach, we derive optimal offspring cannibalism behaviour and parental modifiers that limit or facilitate cannibalism. The results are compared to contemporary frequency‐independent analysis. With the addition of game interactions among siblings or parent‐offspring co‐evolution, our model predicts increased cannibalism (compared to the frequency‐independent prediction), as offspring compete to eat siblings. When infertile eggs are present – strengthening competition – offspring risk eating viable siblings in order to gain access to infertile eggs, intensifying parent‐offspring conflict. We use the results to make new predictions about the occurrence of sibling cannibalism. Additionally, we demonstrate the utility of trophic egg laying as a maternal mechanism to promote egg eating.
Female common lizards (Lacerta vivipara) do not adjust their sex‐biased investment in relation to the adult sex ratio
Authors: LE GALLIARD J.‐F. , FITZE P. S. , COTE J. , MASSOT M. , CLOBERT J.
Published: August 2005

Sex allocation theory predicts that facultative maternal investment in the rare sex should be favoured by natural selection when breeders experience predictable variation in adult sex ratios (ASRs). We found significant spatial and predictable interannual changes in local ASRs within a natural population of the common lizard where the mean ASR is female‐biased, thus validating the key assumptions of adaptive sex ratio models. We tested for facultative maternal investment in the rare sex during and after an experimental perturbation of the ASR by creating populations with female‐biased or male‐biased ASR. Mothers did not adjust their clutch sex ratio during or after the ASR perturbation, but produced sons with a higher body condition in male‐biased populations. However, this differential sex allocation did not result in growth or survival differences in offspring. Our results thus contradict the predictions of adaptive models and challenge the idea that facultative investment in the rare sex might be a mechanism regulating the population sex ratio.
Local adaptation and population structure at a micro‐geographical scale of a fungal parasite on its host plant
Authors: CAPELLE J. , NEEMA C.
Published: August 2005

Local adaptation, which has been detected for several wild pathosystems is influenced by gene flow and recombination. In this study, we investigate local adaptation and population structure at a fine scale in wild populations of a plant‐pathogen fungus. We sampled hierarchically strains of Colletotrichum lindemuthianum in a wild population of its host. The analysis of AFLP patterns obtained for 86 strains indicated that: (i) many different haplotypes can be discriminated, although occurrence of recombination could not be shown; (ii) migration between adjacent plants seemed rare during the season; and (iii) neutral diversity is structured according to groups of plants and individual host plants. Furthermore, we tested for the occurrence of local adaptation using a cross‐inoculation experiment. Our results showed local adaptation at the scale of the individual host plant. These results indicate that fine‐scale dynamics has evolutionary consequences in this pathosystem.
Medicago – Sinorhizobium symbiotic specificity evolution and the geographic expansion of Medicago
Authors: BÉNA G. , LYET A. , HUGUET T. , OLIVIERI I.
Published: August 2005

The legume genus Medicago interacts with soil bacteria commonly referred to as rhizobia, in a nitrogen fixing symbiosis. We analysed the diversity of symbiotic association specificity among the two organisms, and its evolution in the plant genus. Nitrogen fixation tests and molecular phylogenetic reconstructions revealed that the genus Medicago includes more symbiotic specificity groups than previously suggested and that plant specificity is highly unstable and has repeatedly switched along the diversification of this genus. A phylogenetic analysis including geographical data shows that bacterial geographical diversity distribution has a strong influence on the geographic distribution of plant species and their ability to colonize new areas. Multiple other modifications of specificity occurred along the diversification of the genus, presumably due to selection for specialization to a single bacterial biovar. Codivergence between plants and bacteria may also have taken place.
Amount of introgression in flycatcher hybrid zones reflects regional differences in pre and post‐zygotic barriers to gene exchange
Authors: BORGE T. , LINDROOS K. , NÁDVORNÍK P. , SYVÄNEN A. ‐C. , SæTRE G. ‐P.
Published: August 2005

Introgression is the incorporation of alleles from one species or semispecies into the gene pool of another through hybridization and backcrossing. The rate at which this occurs depends on the frequency of hybridization and the fitness of hybrids and backcrosses compared to ‘pure’ individuals. The collared flycatcher (Ficedula albicollis) and the pied flycatcher (F. hypoleuca) co‐exist and hybridize at low to moderate frequencies in a clinal hybrid zone in Central Europe and on the islands of Gotland and Öland off the Swedish east coast. Data on hatching success suggest that hybrids are less fertile in Central Europe compared to on the islands. Direct fitness estimates using molecular markers to infer paternity are consistent with the demographic data. Applying a tag‐array‐based minisequencing assay to genotype interspecific substitutions and single nucleotide polymorphisms we demonstrate that the amount of introgression from the pied to the collared flycatcher is higher in the two island populations (Gotland and Öland) than in two geographically distinct areas from the Central European hybrid zone (Czech Republic and Hungary). In all areas the amount of introgression from collared to pied flycatchers is very low or seemingly absent. The different patterns of introgression are consistent with regional differences in rates of hybridization and fitness of hybrids. We suggest that barriers to gene exchange may have been partly broken down on the islands due to asymmetric gene flow from allopatry. Alternatively, or in addition, more pronounced reinforcement of prezygotic isolation in Central Europe might have increased post‐zygotic isolation through hitchhiking, since genes affecting pre and post‐zygotic isolation are both sex‐linked in these birds. One of our genetic markers appears to introgress from pied to collared flycatchers at a much higher rate than the other markers. We discuss the possibility that the introgressed marker may be linked to a gene which is under positive selection in the novel genetic background.
Inbreeding depression and heterosis in populations of Schiedea viscosa, a highly selfing species
Authors: WELLER S. G. , SAKAI A. K. , THAI D. A. , TOM J. , RANKIN A. E.
Published: August 2005

Progeny from self‐pollinations and intrapopulation crosses were examined in Schiedea viscosa to determine the extent of inbreeding depression in this highly selfing species. Progeny of interpopulation crosses were also investigated to determine whether deleterious alleles have been fixed in populations of S. viscosa. There was no inbreeding depression at early life history stages, including seeds per capsule, seed mass, or germination. Inbreeding depression was detected for the later life history stage of fruit biomass, although not for survival or life span. Heterosis for vegetative biomass and fruit biomass was detected in progeny from crosses between populations. Levels of inbreeding depression in S. viscosa are low relative to out‐crossing species of Schiedea, especially when early life history stages are compared.
Evolution of late-life fecundity in Drosophila melanogaster
Authors: Rauser C. L. , Tierney J. J. , Gunion S. M. , Covarrubias G. M. , Mueller L. D. , Rose M. R.
Published: August 2005

Late-life fecundity has been shown to plateau at late ages in Drosophila analogously to late-life mortality rates. In this study, we test an evolutionary theory of late life based on the declining force of natural selection that can explain the occurrence of these late-life plateaus in Drosophila. We also examine the viability of eggs laid by late-age females and test a population genetic mechanism that may be involved in the evolution of late-life fecundity: antagonistic pleiotropy. Together these experiments demonstrate that (i) fecundity plateaus at late ages, (ii) plateaus evolve according to the age at which the force of natural selection acting on fecundity reaches zero, (iii) eggs laid by females in late life are viable and (iv) antagonistic pleiotropy is involved in the evolution of late-life fecundity. This study further supports the evolutionary theory of late life based on the age-specific force of natural selection.
Why does a grasshopper have fewer, larger offspring at its range limits?
Authors: Hassall M. , Walters R. J. , Telfer M. , Hassall M. R. J.
Published: August 2005

Analysis of size of offspring reared through three laboratory generations from populations of the field grasshopper Chorthippus brunneus from 27 sites around the British Isles showed that offspring were larger towards the cooler-wetter conditions in the western and northern limits of the range. This variation had a significant genetic component. There was a trade-off between clutch size and offspring size between and within populations. Under favourable thermal and feeding conditions maternal fitness was optimal when individuals produced the largest clutches of the smallest eggs, but under poor conditions maternal fitness was optimal when individuals produced small clutches of very large offspring. Calculation of geometric mean fitness over time indicated that having larger offspring near to the edge of the range could be advantageous as a conservative risk-spreading strategy. As well as geographic variation in egg size, significant environment–genotype interactions in egg size in relation to temperature were observed.
Patterns of diversification of Afrotropical Otiteselline fig waSPS: phylogenetic study reveals a double radiation across host figs and conservatism of host association
Authors: Jousselin E. , Van Noort S. , Rasplus J.-Y. , Greeff J. M.
Published: August 2005

We studied the phylogenetic relationships of Otiteselline fig waSPS associated with Ficus in the Afrotropical region using rDNA sequences. African fig species usually host two species of Otiteselline fig waSPS. Phylogenetic analyses reveal that this pattern of association results from the radiation of two clades of waSPS superimposed on the fig system. Within each clade, wasp species generally cluster according to their host classification. The phylogenies of the two clades are also generally more congruent than expected by chance. Together these results suggest that Otiteselline wasp speciation is largely constrained by the diversification of their hosts. Finally, we show a difference in ovipositor length between the two Otiteselline species coexisting in the same Ficus species, which probably corresponds to ecological differences. The diversification of ecological niches within the fig is probably, with cospeciation, one of the key factors explaining the diversification and maintenance of species of parasites of the fig/pollinator system.
Rapid temporal change in the expression and age-related information content of a sexually selected trait
Authors: Hegyi G. , TÖRÖK J. , Tóth L. , Garamszegi L. Z. , Rosivall B.
Published: August 2005

The expression of sexual signals is often phenotypically plastic and also evolves rapidly. Few studies have considered the possibility that proximate determination – the pathway between genes and trait expression – may also be subject to both phenotypic plasticity and evolutionary change. We examined long-term patterns in size, condition- and age-dependence, repeatability and heritability of forehead patch size, a sexually selected plumage trait in male collared flycatchers. We also estimated survival and sexual selection on the phenotypic value of the trait. Forehead patch size linearly declined during the 15 years, probably due to the significantly negative survival selection. In addition, the expression of genetic variation for the ornament apparently underwent an age-limited change, which implies a change in the information content of the signal to receivers. The persistent lack of condition-dependence makes phenotypic plasticity an unlikely explanation to our results. This raises the possibility of a microevolutionary change of both expression and proximate determination during the study period.
Can maternally transmitted endosymbionts facilitate the evolution of haplodiploidy?
Authors: Engelstädter J. , Hurst G. D. D.
Published: August 2005

Whilst many invertebrate taxa are haplodiploid, the factors underlying the evolution of haplodiploidy remain unresolved. We investigate theoretically whether haplodiploidy might evolve as an outcome of the co-evolution between maternally inherited endosymbionts and their hosts. First, we substantially extend a recently developed model that involves maternally inherited endosymbionts that kill male offspring by eliminating the paternal genome. We also put forward a new hypothesis and develop a model that involves bacteria that induce cytoplasmic incompatibility (CI). Based on these models, we explore the co-evolutionary events that might occur between hosts and symbionts. We find that both with male-killers and CI-inducing endosymbionts, the hosts are likely to develop increased viability of haploid males, which can be considered a preadaptation to haplodiploidy. In addition, populations with haploidizing male-killers can in some cases evolve directly towards a genetic system of paternal genome elimination, a special form of haplodiploidy. These results are combined with consideration of mechanism and ecology to appraise the likelihood of male-killers and CI inducing bacteria being involved in the evolution of haplodiploidy.
No evidence for the ‘Meselson effect’ in parthenogenetic oribatid mites (Oribatida, Acari)
Authors: Schaefer I. , Domes K. , Heethoff M. , Schneider K. , Schön I. , Norton R. A. , Scheu S. , Maraun M.
Published: August 2005

It has been hypothesized that in ancient apomictic, nonrecombining lineages the two alleles of a single copy gene will become highly divergent as a result of the independent accumulation of mutations (Meselson effect). We used a partial sequence of the elongation factor-1α (ef-1α) and the heat shock protein 82 (hsp82) genes to test this hypothesis for putative ancient parthenogenetic oribatid mite lineages. In addition, we tested if the hsp82 gene is fully transcribed by sequencing the cDNA and we also tested if there is evidence for recombination and gene conversion in sexual and parthenogenetic oribatid mite species. The average maximum intra-specific divergence in the ef-1α was 2.7% in three parthenogenetic species and 8.6% in three sexual species; the average maximum intra-individual genetic divergence was 0.9% in the parthenogenetic and 6.0% in the sexual species. In the hsp82 gene the average maximum intra-individual genetic divergence in the sexual species Steganacarus magnus and in the parthenogenetic species Platynothrus peltifer was 1.1% and 1.2%, respectively. None of the differences were statistically significant. The cDNA data indicated that the hsp82 sequence is transcribed and intron-free. Likelihood permutation tests indicate that ef-1α has undergone recombination in all three studied sexual species and gene conversion in two of the sexual species, but neither process has occurred in any of the parthenogenetic species. No evidence for recombination or gene conversion was found for sexual or parthenogenetic oribatid mite species in the hsp 82 gene. There appears to be no Meselson effect in parthenogenetic oribatid mite species. Presumably, their low genetic divergence is due to automixis, other homogenizing mechanisms or strong selection to keep both the ef-1α and the hsp82 gene functioning.
The influence of environmental factors, the pollen : ovule ratio and seed bank persistence on molecular evolutionary rates in plants
Authors: Whittle C.-A.
Published: August 2005

One of the main goals of molecular evolutionary biology is to determine the factors that influence the evolutionary rate of selectively neutral DNA, but much remains unknown, especially for plants. Key factors that could alter the mutation rate include environmental tolerances (because they reflect a plants vulnerability to changes in habitat), the pollen : ovule ratio (as it is associated with the number of mitotic divisions) and seed longevity (because this influences the number of generations per unit time in plants). This is the first study to demonstrate that seed bank persistence and drought tolerance are positively associated with molecular evolutionary rates in plants and that pollen : ovule ratio, shade tolerance and salinity tolerance have no detectable relationship. The implications of the findings to our understanding of the impact of environmental agents, the number of cell divisions and cell aging on neutral DNA sequence evolution are discussed.
Fitness consequences of variable maternal provisioning in quacking frogs (Crinia georgiana)
Authors: Dziminski M. A. , Roberts J. D.
Published: August 2005

Variable maternal provisioning may evolve when there is variation in the quality of offspring environments. The frog Crinia georgiana has high variability in egg size both within and between clutches, independent of female phenotype. It breeds in ponds with high spatial and temporal variation in habitat quality. Egg size strongly affected offspring fitness in good and poor quality offspring environments, whether the egg size difference was from between or within clutches. Since there is a trade-off in egg size and number, these fitness consequences translate to strong effects on maternal fitness. In the variable and unpredictable offspring environment of C. georgiana, the maintenance of variable maternal provisioning both within and between clutches is likely to be an evolved response to the offspring environment.
Does genetic diversity hinder parasite evolution in social insect colonies?
Authors: Hughes W. O. H. , Boomsma J. J.
Published: August 2005

Polyandry is often difficult to explain because benefits of the behaviour have proved elusive. In social insects, polyandry increases the genetic diversity of workers within a colony and this has been suggested to improve the resistance of the colony to disease. Here we examine the possible impact of host genetic diversity on parasite evolution by carrying out serial passages of a virulent fungal pathogen through leaf-cutting ant workers of known genotypes. Parasite virulence increased over the nine-generation span of the experiment while spore production decreased. The effect of host relatedness upon virulence appeared limited. However, parasites cycled through more genetically diverse hosts were more likely to go extinct during the experiment and parasites cycled through more genetically similar hosts had greater spore production. These results indicate that host genetic diversity may indeed hinder the ability of parasites to adapt while cycling within social insect colonies.
Temporal dynamics of genotypic diversity reveal strong clonal selection in the aphid Myzus persicae
Authors: Vorburger C.
Published: August 2005

Parthenogenetic organisms often harbour substantial genotypic diversity. This diversity may be the result of recurrent formations of new clones, or it may be maintained by environmental heterogeneity acting on ecological differences among clones. In aphids, both processes may be important because obligate and cyclical parthenogens can form mixed populations. Using microsatellites, I analysed the temporal dynamics of clonal diversity in such a population of the aphid Myzus persicae over a 1-year period. The frequency distribution of clonal genotypes was very skewed, with many rare and few common clones. The relative frequencies of common clones underwent strong and rapid changes indicative of intense clonal selection. Differences in their host associations suggest that these shifts may partly be caused by changes in the abundance of annual host plants. Other selective factors of potential importance are also discussed. New, sexually produced genotypes made a minor contribution to clonal diversity, consistent with the observed heterozygote excess characteristic of predominantly asexual populations in M. persicae.
Host resistance and parasite virulence in greenfinch coccidiosis
Authors: Hõrak P. , Saks L. , Karu U. , Ots I.
Published: August 2005

The question why different host individuals within a population differ with respect to infection resistance is of fundamental importance for understanding the mechanisms of parasite-mediated selection. We addressed this question by infecting wild-caught captive male greenfinches with intestinal coccidian parasites originating either from single or multiple hosts. Birds with naturally low pre-experimental infection retained their low infection status also after reinfection with multiple strains, indicating that natural infection intensities confer information about the phenotypic ability of individuals to resist novel strains. Exposure to novel strains did not result in protective immunity against the subsequent infection with the same strains. Infection with multiple strains resulted in greater virulence than single-strain infection, indicating that parasites originating from different host individuals are genetically diverse. Our experiment thus demonstrates the validity of important but rarely tested assumptions of many models of parasite-mediated selection in a wild bird species and its common parasite.
Sexual reproduction advances autumn leaf colours in mountain birch (Betula pubescens ssp. czerepanovii)
Authors: Sinkkonen A.
Published: August 2005

Autumnal change in leaf colour of deciduous trees is one of the most fascinating displays in nature. Current theories suggest that autumn leaf colours are adaptations to environmental stress. Here I report that the number of ripening female catkins altered timing of yellow autumn leaf colours in mountain birch. The tree's autumnal colour change was brought forward if the tree matured plenty of female catkins. Since yellow colour pigments in leaves are unmasked as leaf nitrogen is re-translocated, sexual reproduction may alter resource allocation at times of leaf senescence. Thus, our current view on the reasons for leaf senescence has to be re-examined, and a novel evolutionary explanation is needed for the appearance of yellow autumn leaf colours.
Frost Injury as a Possible Inciting Factor in Bud and Shoot Necroses of Fraxinus excelsior L.
Authors: Pukacki P. M. , Przybył K.
Published: August 2005

Large numbers of European ash have died in Poland in all age classes during the last ten years. The characteristic symptom occurring on shoots of planted and self‐sown seedlings was bark necroses starting from the shoot apex, necrotic buds, or leaf and twig scars. The results showed that in the bud tissue of cold acclimated European ash extracellular and intracellular ice formation occurred at approximately −9 and −32°C, respectively. In deacclimated plants in spring water supercooling is limited by the heterogenous ice nucleation temperature and consequently the cold tolerance is −9 to −4°C for bud tissues and −13 to −9°C for shoots. Isolations of fungi were performed from dead buds and from necroses occurring on the main stem. Alternaria alternata, Fusarium lateritium and Phomopsis scobina were among the fungi occurring in both these organs at frequencies of more than 7%. Cylindrocarpon heteronemum, Diplodia mutila and Tubercularia vulgaris from necroses were only isolated in frequencies; 3.3, 1.2 and 5.4%, respectively. It seems likely that freezing injury is the inciting factor, which combined with fungal colonization manifests itself as fatal damage to European ash buds and shoots.
THE PARADOX OF BENEFICIAL RETIREMENT
Authors: Smilansky Saul
Published: August 2005

Morally, when should one retire from one's job? The surprising answer may be ‘now’. It is commonly assumed that for a person who has acquired professional training at some personal effort, is employed in a task that society considers useful, and is working hard at it, no moral problem arises about whether that person should continue working. I argue that this may be a mistake: within many professions and pursuits, each one among the majority of those positive, productive, hard working people ought to consider leaving his or her job.
FOETAL AND MATERNAL ACID‐BASE BALANCE DURING NORMAL LABOUR
Authors: Beard R. W. , Morris E. David
Published: August 2005

Summary

(1) Twenty‐six patients whose labours have been judged to be normal have had samples of venous blood taken at the same time as samples of foetal scalp capillary blood at different stages of labour.

(2) Using the Astrup micromethod, pH, base excess, and Pco2 estimations have been made on this blood. There is an initial improvement in the maternal and foetal values which is slowly reversed as labour progresses.

(3) A constant maternal‐foetal acid‐base difference has been shown to exist at all stages of labour.

(4) The suitability of foetal scalp capillary blood for these estimations is demonstrated by the similarity of the acid‐base values of foetal scalp blood taken at full cervical dilatation with the head in the pelvic cavity.
TIME: AN IMPORTANT VARIABLE AT CAESAREAN SECTION
Authors: Lumley Judith , Walker Adrian , Marum John , Wood Carl
Published: August 2005

Biochemical evidence of fetal asphyxia (relative hypoxia with hypercapnia) and acidaemia has been found in the cord blood of infants delivered by Caesarean section in a series of patients who had been selected to exclude complications of pregnancy which prejudiced the fetal condition before or during anaesthesia. Further, the findings strongly suggest that fetal asphyxia develops progressively, and Apgar scores were lower as the duration of anaesthesia was extended. While changes with time in the general circulation and respiration of the mother could be excluded as the cause of fetal deterioration, local changes in the utero‐placental circulation, due to recumbency or surgical manipulation, and the effect of anaesthetic agents could not.
LAPAROSCOPY IN THE DIAGNOSIS OF TUBAL PATENCY
Authors: Coltart T. M.
Published: August 2005

Thirty‐six patients with a diagnosis of bilateral tubal occlusion on hysterosalpingography subsequently underwent laparoscopy and injection of dye through the cervix into the uterus. Bilateral tubal patency was demonstrated in 11 patients (31 per cent) and unilateral patency in 7 more (19 per cent). In view of the poor results from tubal plastic procedures it is advocated that laparoscopy be carried out before tubal surgery on all patients with bilateral negative salpingograms, especially to cases with apparent occlusion at the fimbria.
ENDOMETRIAL CARCINOMA AND SYNTHETIC PROGESTOGENS RESULTS OF INTRAUTERINE TREATMENT
Authors: Hustin J.
Published: August 2005

Eleven patients with endometrial carcinoma have been treated by intrauterine instillations of progestogen in oil during six days prior to hysterectomy. The histological changes in the hysterectomy specimens have been recorded.

Good results were attained in all cases, with disappearance of the tumour in three of them. The mode of action of the progestogens is discussed.
URGE AND STRESS INCONTINENCE FACT AND FICTION
Authors: Frewen W. K.
Published: August 2005

A preliminary postoperative follow‐up of 600 personal cases of stress incontinence was made. A complete analysis of 412 of these cases had been accomplished up to the date of publication.

This analysis showed a postoperative cure rate of 74·3 per cent. The apparent postoperative failure rate of 25·7 per cent (106 cases), which is in line with the majority of published works, is misleading and, indeed, fictitious. Incontinence of urine in 76 of the 106 cases was due to urge incontinence.

The exclusion of urge incontinence by the psychomedical therapeutic test is an essential preliminary in almost all cases of incontinence. The operative results from primary vaginal surgery are probably much better than those usually postulated.

Twenty‐three cases had had two or more operations and in all of these the incontinence was of the urge variety.

The extensive literature on incontinence of urine in the female has not established with sufficient emphasis the role of urge incontinence and its symptomatic similarity to stress incontinence. The two conditions are frequently indistinguishable clinically and may well need a searching investigation in hospital to clarify the diagnosis.

The psychomedical therapeutic test is a simple and practical method of differentiating one type of incontinence from the other and, in the author's opinion, should be universally adopted in almost all cases of incontinence of urine. This, in particular, applies to all cases of recurrent incontinence after previous surgery.
SERUM HEAT‐STABLE ALKALINE PHOSPHATASE IN PREGNANCY COMPLICATED BY HYPERTENSION
Authors: Benster Barry
Published: August 2005

Serum heat‐stable alkaline phosphatase was measured during the third trimester in 72 normal pregnant women and 168 women with hypertension in pregnancy. The method used was specific for the placental isoenzymes. In normal pregnant women the mean level increased with the maturity of the pregnancy. Patients with hypertension had a greater incidence of abnormal levels, with a tendency for high serum HSAP levels at 28–32 weeks and normal or low levels in later pregnancy.
THE EFFECT OF ATP ON THE FETUS IN DANGER DURING LABOUR
Authors: Horská S. , ŠTembera Z. K. , Vondráček J.
Published: August 2005

By administering ATP to the mother during delivery fetal hypoxia was relieved in respect of both metabolic and gaseous exchange. However, there was no difference between doses of 20 and 40 mg. ATP. The metabolic improvement of the fetus during delivery was also reflected by the more favourable condition of the infants at birth.
THE EFFECTS OF SCHISTOSOMIASIS ON THE FALLOPIAN TUBES IN THE AFRICAN FEMALE
Authors: Bland K. G. , Gelfand M.
Published: August 2005

In a prospective study 10 patients out of 104 from an endemic bilharzial country showed definite evidence of bilharziasis in the Fallopian tubes.

Unless the inflammatory reaction is severe, the presence of the ova is of little or no significance, but if there is a severe fibrous or granulomatous reaction of the tubes to the ova ectopic pregnancy may ensue.

No significant effect of bilharziasis on fertility was shown.

S. haematobium is the commonest type of schistomsoma affecting the Fallopian tubes.
A METHOD OF TREATING VAGINAL VAULT PROLAPSE
Authors: Thursz A. D.
Published: August 2005

An abdominal operation for the treatment of vaginal vault prolapse is described; this involves hitching the vault with a synthetic tape inserted along the lines of the round ligaments and fastened to the external oblique aponeurosis.
ULTRASONIC FETAL CEPHALOMETRY DURING THE SECOND TRIMESTER OF PREGNANCY
Authors: Campbell Stuart
Published: August 2005

The accuracy of ultrasonic cephalometry by the combined A and B scan method was assessed in 50‐second trimester fetuses which were delivered by hysterotomy. A good correlation was obtained between the antenatal ultrasonic and postnatal caliper measurement. It is concluded that the fetal biparietal diameter can be accurately measured from 13 weeks onwards.
THE MEASUREMENT OF EXTRACELLULAR FLUID VOLUME IN PREGNANCY WITH INULIN
Authors: Robertson Euan G. , Hytten F. E. , Cheyne G. A.
Published: August 2005

Extracellular fluid volume estimated serially during pregnancy by inulin in seven subjects showed large variations from time to time in the same subject. Practical and theoretical objections are advanced to the use of inulin as a tracer in pregnancy.
COMPARISON BETWEEN PLASMA OESTRIOL AND URINARY OESTRIOL LEVELS IN PREGNANCY
Authors: MacRae D. J. , Mohamedally S. M.
Published: August 2005

In a comparison of 51 pairs of plasma oestriol and urinary oestriol levels during pregnancy the correlation coefficient was highly significant. This close relationship of plasma and urinary oesiriol values was present not only in normal pregnancy, but also in the serial assays made in pregnancy complications. No significant variation in plasma oestriol values was found between blood samples taken in the morning and evening.
ACID‐BASE RELATIONSHIPS ACROSS THE SHEEP PLACENTA
Authors: Curet Luis B.
Published: August 2005

The umbilical artery and uterine vein blood pH, base excess and bicarbonate concentrations were measured in sheep in acute and chronic experiments. The lack of correlation between these parameters suggest that in the ewe the placenta is not the main regulator of fetal acid base balance.
FURTHER SIMPLIFICATIONS IN THE DETECTION OF FETAL HAEMOGLOBIN IN CLINICAL PRACTICE
Authors: Chamberlain Geoffrey , Fosker A. P.
Published: August 2005

A simple tablet test for distinguishing between adult and fetal haemoglobin in small samples of blood is described. It is useful in connection with fetal blood sampling, amniocentesis, ruptured vasa praevia and blood swallowed by the baby at delivery.
SURVEY OF MATERNAL DEATHS IN SOUTH IRAN ANALYSIS OF 96 AUTOPSIES
Authors: Daneshbod Khosrow , Borazjani Gholam Reza , Sajadi Hasan , Hamidzadeh Mohamed Mehdi
Published: August 2005

Cases of maternal death on which autopsies were carried out during 1963–9 at Saadi Hospital of Pahlavi University have been reviewed. All deaths, regardless of the cause, in pregnant women at any period of gestation or within 90 days of termination of pregnancy were included in the study. The autopsy rate was 90 per cent. Seventy‐three per cent of the patients were from the surrounding district and 27 per cent from the urban area. None of the mothers had antenatal care. The cause of deaths was classified as direct obstetric in 46 per cent of cases, as indirect obstetric in 36 per cent and unrelated in 18 per cent. In all three groups, infection was the leading cause of death.
MATERNAL DEATH FROM SYSTEMIC SCLEROSIS
Authors: Sood S. V. , Kohler H. G.
Published: August 2005

A young nulliparous patient with over two years' history of scleroderma was allowed to proceed with her pregnancy, but at the beginning of the third trimester she developed severe hypertension and proteinuria which did not respond to treatment. Left ventricular failure and terminal right ventricular failure preceded death. The postmortem histological findings confirmed the presence of systemic sclerosis.
SYNTOCINON INDUCED CONVULSION
Authors: Pedlow P. R. B.
Published: August 2005

A case is described in which water intoxication with convulsions followed the administration of a concentrated Syntocinon infusion over a period of four days. Prevention, management and prognosis are discussed.
THE EFFECTS OF SCHISTOSOMIASIS ON THE CERVIX UTERI IN THE AFRICAN FEMALE
Authors: Bland K. G. , Gelfand M.
Published: August 2005

In a prospective study of 55 African patients in whom the cervix uteri was removed and examined, 12 showed definite evidence of bilharziasis and 9 of these had evidence of bilharziasis elsewhere on routine screening.

The 12 patients who had bilharzial cervicitis were clinically analyzed in detail. Only rarely does cervical bilharziasis simulate cervical carcinoma, but it may give rise to suspicious abnormal vaginal bleeding. The need for careful biopsy of all suspicious cervical lesions in endemic areas is emphasized, and the value of anti‐bilharzial treatment in proven cases, is stressed.

In our experience, based on a series of 18 consecutive cases of cervical carcinoma, there is no correlation with cervical bilharziasis.
INCIDENTAL PATHOLOGY AT VAGINAL HYSTERECTOMY FOR GENITAL PROLAPSE
Authors: Bonnar John , Kraszewski Andrew , Davis W. B.
Published: August 2005

In 500 patients with uterovaginal prolapse who were treated by vaginal hysterectomy incidental gynaecological lesions which were unsuspected until after removal of the uterus were found in 129 patients (26 per cent). Fibromyomata were the commonest finding but endometrial abnormalities were present in 46 patients (9·2 per cent) and small ovarian tumours in 13 patients (2·6 per cent). In a patient who has completed her family or who is beyond the child‐bearing years the removal of the uterus as an integral part of the operation for the repair of utero‐vaginal prolapse allows the removal of unsuspected lesions which could be significant in later life.
AN ANALYSIS OF MASSIVE PULMONARY HAEMORRHAGE IN THE NEWBORN INFANT IN OXFORD, 1948–68
Authors: DeSa D. J. , MacLean B. S.
Published: August 2005

On reviewing the cases of massive pulmonary haemorrhage in newborn infants in Oxford over the years 1948 to 1968, inclusive, 49 cases not associated with major congenital malformations were traced. These cases were not uniformly distributed over these years; there was a progressive decline in incidence which parallelled the decline in stillbirth and neonatal mortality rates. Massive pulmonary haemorrhage was found to be associated with a wide range of aetiological factors, and analysis of these factors by the Aberdeen Clinico‐pathological Classification showed that the decrease in incidence was due to improvements in obstetrical care and organization. Some differences from the findings of the Perinatal Mortality Survey are presented, and the seasonal distribution of cases born outside the hospital is shown. Lt is concluded that many cases of massive pulmonary haemorrhage may be prevented.
THE VALUE OF AMNIOTIC FLUID EXAMINATION IN THE ASSESSMENT OF FETAL MATURITY
Authors: Sharma Santosh D. , Trussell Richard R.
Published: August 2005

Four hundred and sixty‐eight specimens of amniotic fluid were examined from 418 patients at various stages of pregnancy and in the first stage of labour. After staining with Nile blue sulphate, the percentage of orange‐staining cells, the presence of vernix caseosa and free lipid were helpful in determining fetal maturity. The relationship between fetal maturity and the percentage of orange‐staining cells was confirmed by the examination of serial samples of amniotic fluid from the same patient. There was no difference in the percentage of orange‐staining cells in each sac of 19 twin pregnancies. The technique was particularly valuable for distinguishing between immature and small‐for‐dates infants and was useful in assessing fetal maturity in patients for whom induction of labour or elective Caesarean section was planned.