bluuebunny/crossref_metadata_2025_split huggingface dataset:
Cryptic male choice: sperm allocation strategies when female quality varies
Authors: Reinhold K. , Kurtz J. , Engqvist L. 
Published: March 2003

Abstract
We examined evolutionary stable sperm allocation and included stochastic variation in male mating frequency, not included in previous models examining sperm allocation strategies. We assumed sperm mixing and variation in female quality and used a genetic algorithm to analyse the evolution of male sperm allocation. Our results show that males should invest more sperm in initial copulations than in subsequent copulations as a male might fail to mate again. The inclusion of variation in female fecundity had no influence on the evolutionary stable sperm allocation strategy if males were unable to recognize female quality. If males were assumed to allocate sperm in response to female quality, the proportion of sperm allocated was positively correlated with female quality. Moreover, with increasing variance in female quality, males conserved more sperm for later copulations. Literature data on sperm allocation from diverse taxa show a good fit with the predictions given by our model.
Different mate preferences by parasitized and unparasitized females potentially reduces sexual selection
Authors: Pfennig K. S. , Tinsley R. C. 
Published: March 2003

Abstract
Parasite-mediated models of sexual selection predict that females should avoid parasitized mates, thereby generating selection on male traits revealing health. The strength of this selection, however, may depend on the prevalence of parasitism among females if their infection status alters their mate preferences. We evaluated the effects of a socially transmitted parasite on male traits and female behaviour in spadefoot toads. Parasitized males were larger and in better condition than unparasitized males. Moreover, better condition males produced longer calls. Unparasitized females preferred longer calls indicative of good-condition males that are more likely parasitized. By contrast, parasitized females as a group possessed no preference for call duration. Presumably because of reduced selection by these parasitized females, male mating success was not associated with any measured traits. Thus, when females are parasitized, sexual selection on condition-dependent traits is potentially reduced.
Evolutionary responses of Drosophila melanogaster to selection at different larval densities: changes in genetic variation, specialization and phenotypic plasticity
Authors: Pérez A. , García C. 
Published: March 2003

Abstract
We studied the evolutionary response to novel environments by applying artificial selection for total progeny biomass in populations of Drosophila melanogaster maintained at three different larval population densities. We found the relative amount of genetic variability for characters related with biomass to be lower and the correlation between them more negative at the intermediate density, and that selection resulted in changes in phenotypic plasticity and in patterns of resource allocation between traits. We found some evidence for tradeoffs between densities, which suggests that populations living at heterogeneous densities might be subject to disruptive selection. Our results show that adaptation to new environments may be a complex process, involving not only changes in trait means, but also in correlations between traits and between environments.
Evolution of the distribution of dispersal distance under distance-dependent cost of dispersal
Authors: Rousset F. , Gandon S. 
Published: March 2003

Abstract
We analyse the evolution of the distribution of dispersal distances in a stable and homogeneous environment in one- and two-dimensional habitats. In this model, dispersal evolves to avoid the competition between relatives although some cost might be associated with this behaviour. The evolutionarily stable dispersal distribution is characterized by an equilibration of the fitness gains among all the different dispersal distances. This cost-benefit argument has heuristic value and facilitates the comprehension of results obtained numerically. In particular, it explains why some minimal or maximal probability of dispersal may evolve at intermediate distances when the cost of dispersal function is an increasing function of distance. We also show that kin selection may favour long range dispersal even if the survival cost of dispersal is very high, provided the survival probability does not vanish at long distances.
Genetics of wing size asymmetry in Drosophila buzzatii
Authors: Santos M. 
Published: March 2003

Abstract
Contemporary approaches that use fluctuating asymmetry (FA) as a possible target for natural and sexual selection are based on the premise that FA is a quantifiable expression of developmental instability (DI) that is inherited. Previous work with Drosophila buzzatii found that male mating success was correlated positively to body size (wing length) and negatively to FA, but these relationships seem to be environmentally induced. Heritability of FA was low and not significantly different from zero, but statistical power was also estimated to be very low and, hence, no conclusive evidence could be obtained. A large half-sib mating design is used here to examine the relationships of different aspects of development for wing size. Consistently with previous findings, I found high heritabilities for wing length (WL) and wing width (WW), and positive correlations between both traits.  Heritabilities of FA (FAWL, FAWW) were low (0.037) but significantly different from zero, and the genetic correlation between FAWL and FAWW was estimated as −1 because the absolute value for the genetic covariance was similar in magnitude or even larger than the estimated genetic variances of both traits. This suggests that these two traits should be considered to be the same character. The between-trait phenotypic correlation in FA, which reduces to the repeatability in this situation, was positive and statistically significant thus rendering an estimate of heritability for DI in D. buzzatii of . Nevertheless, the fact that left/right wing sizes were found to be determined by the same set of genes is difficult to reconcile with the presence of special genetic mechanisms that stabilize left/right development in this species. A qualitatively different pattern for asymmetry was observed when the nonlinear composite character wing area (WA ≈ WL × WW) was used, and . Although the results could be made compatible with the existence of a diallelic locus with antagonistic pleiotropic effects on FAWL and FAWW that combine multiplicatively to produce overdominance for FAWA, the available evidence is extremely weak at best. Finally, a test to the null hypothesis of a nongenetic basis of FA, particularly relevant to those situations when directional asymmetry may be heritable, is suggested.
Selection experiments and the study of phenotypic plasticity
Authors: Scheiner S. M. 
Published: March 2003

Abstract
Laboratory selection experiments are powerful tools for establishing evolutionary potentials. Such experiments provide two types of information, knowledge about genetic architecture and insight into evolutionary dynamics. They can be roughly classified into two types: (1) artificial selection in which the experimenter selects on a focal trait or trait index, and (2) quasi-natural selection in which the experimenter establishes a set of environmental conditions and then allows the population to evolve. Both approaches have been used in the study of phenotypic plasticity. Artificial selection experiments have taken various forms including: selection directly on a reaction norm, selection on a trait in multiple environments, and selection on a trait in a single environment. In the latter experiments, evolution of phenotypic plasticity is investigated as a correlated response. Quasi-natural selection experiments have examined the effects of both spatial and temporal variation. I describe how to carry out such experiments, summarize past efforts, and suggest further avenues of research.
Host choice promotes reproductive isolation between host races of the larch budmoth Zeiraphera diniana
Authors: Emelianov I. , Simpson F. , Narang P. , Mallet J. 
Published: March 2003

Abstract
The chances for sympatric speciation are improved if ecological divergence leads to assortative mating as a by-product. This effect is known in parasites that find mates using host cues, but studies of larch- and pine-feeding races of the larch budmoth (Zeiraphera diniana, Lepidoptera: Tortricidae) suggest it may also occur when mate attraction is via sex pheromones that are independent of habitat. We have previously shown that females releasing pheromones on or near their own host attract more males of their own race than if placed on the alternative host. This host effect would enhance assortative mating provided adults preferentially alight on their native hosts. Here we investigate alighting preferences in natural mixed forest using a novel likelihood analysis of genotypic clusters based on three semidiagnostic allozyme loci. Both larch and pine females show a realized alighting preference for their own host of 86%. The equivalent preferences of males were 79% for the larch race and 85% for the pine race. These preferences are also detectable in small-scale laboratory experiments, where alighting preferences of larch and pine races towards their own hosts were, respectively, 67 and 66% in females and 69 and 63% in males. Pure larch race moths reared in the laboratory had alighting choice similar to moths from natural populations, while hybrids were intermediate, showing that alighting preferences were heritable and approximately additive. The field estimates of alighting preference, coupled with earlier work on mate choice, yield an estimated rate of natural hybridization between sympatric host races of 2.2–3.8% per generation. Divergent alighting choice enhances pheromone-mediated assortative mating today, and is likely to have been an important cause of assortative mating during initial divergence in host use. Because resources are normally ‘coarse-grained’ in space and time, assortative mating due to ecological divergence may be a more important catalyst of sympatric speciation than generally realized.
Rapid detection of antibodies to immunoglobulin A molecules by using the particle gel immunoassay
Authors: Salama A. , Schwind P. , Schönhage K. , Genth R. , Cotting C. , Hustinx H. , Krieg R. , Nydegger U. , Aebischer I. 
Published: March 2003

Background and ObjectivesAntibodies to immunoglobulin A (IgA) molecules are thought to be frequently responsible for anaphylactic reactions in transfusion medicine, but practical tests for the detection of antibodies to IgA are not yet available.Material and MethodsRed, high‐density polystyrene beads were coated with purified IgA molecules and then used to test serum samples collected from unselected healthy blood donors (n = 105) and patients with common variable immunodeficiency and/or IgA deficiency (n = 44). For testing, the standard gel‐agglutination technique (ID‐Micro Typing System) was employed.ResultsNone of the normal serum samples were reactive with IgA‐coated beads and samples from only 10 patients were positive (titre range 1 : 2 to 1 : 256). Only one out of all patients studied had a history of an anaphylactic reaction and this was related to the administration of Rh(D) prophylaxis (anti‐D immunoglobulin). The beads did not show non‐specific agglutination and could be used repeatedly for longer than 6 months. The results were reproducible in all patients tested.ConclusionThe new test allows a specific and rapid detection of antibodies to IgA molecules. In order to evaluate the clinical relevance of the test, analysis is required of a wider range of antibodies that produce anaphylactic reactions.
Molecular characterization of weak D phenotypes by site‐directed mutagenesis and expression of mutant Rh–green fluorescence protein fusions in K562 cells
Authors: Kamesaki T. , Iwamoto S. , Kumada M. , Omi T. , Okuda H. , Tanaka M. , Takahashi J. , Obara K. , Seno T. , Tani Y. , Kajii E. 
Published: March 2003

Background and ObjectivesMutations detected in 161 weak D samples from Caucasians have been classified into 16 types. Because flow cytometry using monoclonal anti‐D antibodies (mAbs) has shown that weak D red cells display type‐specific antigen density, these mutations in transmembranous regions have been assigned weak D phenotypes. The present study attempts to confirm or refute this assignment.Materials and MethodsWe amplified DNA from four Japanese weak D samples using the polymerase chain reaction (PCR), and directly sequenced the amplified DNA. Using site‐directed mutagenesis, we constructed three vectors expressing mutantRHDs – G212C, V270G (weak D type 1) and G358A (type 2) – in K562 cells. The expression of RhD antigens was examined by flow cytometry using mAbs.ResultsA new mutation resulting in a conversion at amino acid residue 212 (Gly to Cys) was detected in a Japanese weak D sample. K562 cells transduced with mutantRhDcDNA reacted weakly in a type‐specific manner with mAbs.ConclusionsThe mutations – G212C (new weak D type), V270G (weak D type 1) and G358A (type 2) – in transmembranous regions had obvious effects on the D epitopes recognized by mAbs. The results of this study provide direct evidence that these mutations can account for weak D phenotypes.
Anti‐U‐like: a common antibody in Black individuals
Authors: Janvier D. , Lam Y. , Maury J. 
Published: March 2003

Background and Objectives Anti‐Uz, a scarce antibody, defines a glycophorin B high‐incidence antigen, which is protease‐sensitive. In a few years, we have encountered 12 antibodies of similar specificity, made by Black individuals of the S− s+ U+ phenotype.Materials and Methods Antibodies were characterized by serological methods, with common and rare MNS types, as well as red cells treated with various proteases.Results Anti‐U‐like, mostly an autoantibody, was of IgG class and reacted optimally by indirect antiglobulin test at 20 °C. The corresponding antigen was destroyed by several proteases. Tests with papain‐treated or Dantu+ cells suggested the existence of several subspecificities.Conclusion Anti‐U‐like is common in the African population, though its reactions are often misinterpreted. The fact that antibody producers are always Black patients remains unexplained. No relationship with a pathological state could be established.
Prestorage leucocyte reduction of red cell components prevents release of bactericidal permeability increasing protein and defensins
Authors: Fransen E. J. , Rombout‐Sestrienkova E. , Van Pampus E. C. M. , Buurman W. A. , Reutelingsperger C. P. M. , Maessen J. G. 
Published: March 2003

Background and Objectives In this study we examined whether prestorage leucocyte reduction prevents the accumulation of bioreactive substances in red cell units.Materials and Methods Measurements were performed in the supernatants of buffy‐coat‐depleted (standard red cells) and leucocyte‐reduced (filtered red cells) red cell units. The effect of storage was evaluated by taking repetitive samples up to 35 days after donation. We determined the concentrations of polymorphonuclear neutrophil (PMN)‐derived bactericidal permeability increasing protein (BPI), defensins and annexin A5. In addition, leucocyte counts (using nageotte chamber) were performed on days 0 and 35.Results During storage, the concentrations of BPI, defensins and annexin A5 in standard red cells gradually increased. However, in the filtered red cells BPI and defensins were found in only a few samples, whereas the annexin A5 concentration in these units did not change during storage. Haemolysis data in both types of red cell components were similar at all time‐points, except prestorage. Significant correlations were found between the release of BPI, defensins and annexin A5 into red cell units and the loss of leucocytes during storage.Conclusions PMNs lose their membrane integrity during cold storage and release their contents into red cell components. Prestorage leucocyte reduction of red cell components prevents the accumulation of BPI, defensins and annexin A5.
Cytokine levels as performance indicators for white blood cell reduction of platelet concentrates
Authors: Wadhwa M. , Krailadsiri P. , Dilger P. , Gaines Das R. , Seghatchian M. J. , Thorpe R. 
Published: March 2003

Background and ObjectivesWith the implementation of universal white blood cell (WBC) reduction in the UK, in‐process WBC‐reduction filters for pooled buffy coat (BC)‐derived platelet concentrates (PCs) and apheresis methods are used routinely for the production of WBC‐reduced PCs. While these strategies meet the specification for WBC reduction (< 5 × 106WBCs/unit), the products from these processes may differ depending on the process employed and its performance. The aim of this study was therefore to investigate whether PCs prepared using various WBC‐reduction processes are sufficiently depleted of WBCs to limit cytokine accumulation during storage and to assess if cytokine levels detected in platelet products can serve as indicators of acceptable platelet activation as a result of the WBC‐reduction process.Materials and MethodsWe measured the levels of cytokines predominantly derived from WBCs [e.g. interleukin‐8 (IL‐8)] and platelets [e.g. regulated on activation, normal, T‐cell expressed, and secreted (RANTES) and transforming growth factor‐β1(TGF‐β1)] under the present experimental conditions in different WBC‐reduced PCs, i.e. PCs prepared from three different WBC‐reduction filters and control non‐filtered PCs using pooled BCs from the same donors and three apheresis types. Supernatant plasma was collected at the beginning (day 1) and end (day 5) of the shelf life of each PC, and the cytokine content was determined using appropriate enzyme‐linked immunosorbent assays (ELISAs). Process efficiency was assessed by platelet yield and residual WBC count.ResultsWe found that products from the apheresis process involving a filtration step (Haemonetics MCS+) showed a lower cytokine content on both day 1 and day 5 in comparison with the fluidized bed (COBE Spectra) or elutriation (Amicus) processes. WBC reduction of BC‐PCs of the same origin using three different filters showed comparable levels of cytokines on day 1 in all units. After storage for 5 days, the levels of IL‐8 remained essentially unchanged in filtered BC‐PCs but increased by more than threefold in control non‐filtered BC‐PCs, suggesting IL‐8 release by residual WBCs present in the control PCs. The concentration of platelet‐derived cytokines such as RANTES and TGF‐β1, however, increased significantly in all filtered and control non‐filtered PCs during the storage period.ConclusionThese results show that markers of cytokine release from both WBCs and platelets are useful indicators of the performance and efficacy of the WBC‐reduction process and of platelet quality.
Purification of human immunoglobulin G: a new approach to plasma fractionation
Authors: Li G. , Stewart R. , Conlan B. , Gilbert A. , Roeth P. , Nair H. 
Published: March 2003

Background and Objectives Currently, plasma fractionation involves multiple processing steps using established methods such as ethanol precipitation and column chromatography. The known limitations associated with conventional purification techniques, combined with strict regulations on safety and high demand for particular plasma proteins, have resulted in a shortage of plasma‐derived therapeutics such as intravenous immunoglobulin G (IgG).Materials and Methods In this study, IgG was purified from human plasma using Gradiflow technology, an electrophoresis‐based separation technology.Results IgG was isolated from plasma to high purity, with 94 ± 5% recovery in a short processing time.Conclusions The technology has been shown to be linearly scalable and has the capacity to contribute to increased production of important plasma fraction therapeutics.
Inactivation of viral and prion pathogens by γ‐irradiation under conditions that maintain the integrity of human albumin
Authors: Miekka S. I. , Forng R.‐Y. , Rohwer R. G. , MacAuley C. , Stafford R. E. , Flack S. L. , MacPhee M. , Kent R. S. , Drohan W. N. 
Published: March 2003

Background and Objectives The administration of therapeutic plasma protein concentrates has been associated with the real risk of transmitting viral diseases and the theoretical risks of prion transmission. Our objective was to determine if γ‐irradiation can inactivate viral or prion infectivity without damaging a protein biotherapeutically.Materials and Methods Human albumin 25% solution, spiked with four model viruses (including porcine parvovirus) or with brain homogenate from scrapie‐infected hamsters, was γ‐irradiated at constant low‐dose rates and assayed for viral and prion infectivity or for albumin integrity.Results At a radiation dose of 50 kGy, viruses were inactivated by ≥ 3·2 to ≥ 6·4 log10 and scrapie by an estimated 1·5 log10, whereas albumin was only moderately aggregated and fragmented.Conclusions γ‐Irradiation can preferentially inactivate viral and prion pathogens without excessive damage to albumin structure.
The blood‐donation experience: perceived physical, psychological and social impact of blood donation on the donor
Authors: Nilsson Sojka B. , Sojka P. 
Published: March 2003

Background and Objectives This study aimed to investigate the impact and effects of blood donation on blood donors as perceived and reported by donors themselves.Materials and Methods A self‐administered questionnaire was distributed to 600 consecutive whole‐blood donors (who had a history of at least one previous donation) consisting of an open‐ended question asking whether the blood donation had any impact on the donor. The answers to this question were considered as descriptions of effects perceived by the donors to be evoked by whole‐blood donation.Results In all, 528 subjects completed the questionnaire (88%; 319 males and 209 females) and answered the question about the effects of blood donation. Altogether, 54% (287 out of 528) of the blood donors reported one or several effects. Exclusively positive effects were described by 29% (151) of blood donors, while exclusively negative effects and mixed effects (i.e. concomitant positive and negative effects in the same subject) were described by 19% (103) and 6% (33), respectively, while no effect was reported by 46% (241) of the donors. A majority of the effects commenced within 1 h of blood donation. The positive effects lasted significantly longer (often for weeks, P < 0·0001) than negative effects (min/h/days). Among positive effects a feeling of satisfaction, of being more alert, and feeling generally better than before the blood donation predominated for both female and male donors. Among negative effects, vertigo/dizziness was reported more frequently by female donors (P < 0·0001). Logistic regression analysis revealed that the negative effects were less likely to occur with increasing age (P < 0·001) and that they were more likely to occur in female donors (P < 0·001) in comparison to male donors, irrespective of age.Conclusions The majority of effects elicited by blood donation on blood donors were positive (i.e. feelings of satisfaction, greater alertness, increased wellbeing, etc.). The positive effects did not differ from the negative regarding time of onset, yet their duration was reported to be significantly longer. There was no association between frequency of occurrence of positive effects and the number of blood donations, indicating that there is no ‘addictive’ relationship between donors and blood donations. The findings in this study of high frequency of occurrence of positive long‐lasting effects elicited in blood donors by blood donation may be of great importance for the recruitment of new blood donors as it may make blood donation less frightening and perhaps even attractive.