bluuebunny/crossref_metadata_2025_split huggingface dataset:
Molecular phylogeny of araneomorph spiders
Authors: Hausdorf B. 
Published: March 2003

Abstract
The reconstruction of the phylogeny of spiders based on morphological and ethological characters is hampered by frequent homoplasies. Therefore, fragments of the 28S rRNA gene have been sequenced to elucidate some crucial points in the evolution of spiders. The following results were obtained. (1) The 28S rRNA gene data support the monophyly of the Entelegynae. Thus, the number of different subunits and the number of hexamers which form a haemocyanin complex must have been reduced at least twice within the spiders. The character state pattern within the spiders and within the Arachnida suggests that these reductions are due to a decrease in the selection on the oxygen binding properties of the haemocyanins as a result of the evolution of tracheae. (2) The semientelegyne spiders are not a transition stage between the Haplogynae and the Entelegynae. The lack of separate fertilization ducts in these species is probably due to secondary reduction. This reduction has decisive consequences for the flow of the sperm and for sperm competition. (3) Furthermore, the 28S rRNA gene data tentatively support the hypothesis that the orb web is either a plesiomorphy or has evolved at least twice.
Variation in morphological traits and trait asymmetry in field Drosophila serrata from marginal populations
Authors: Jenkins  , Hoffmann  
Published: March 2003

Abstract
Drosophila serrata occurs along the eastern coast of Australia with a southern range boundary near Sydney. To compare levels of phenotypic variation in marginal and central populations, we examined morphological variation in populations of this species from the southern range boundary and two more northerly populations. The populations differed for wing traits and there was an increase in wing size in the marginal locations which persisted under laboratory culture. The means of wing and bristle traits increased under laboratory culture, whereas wing trait coefficients of variation and variances decreased. Heritability estimates for wing size traits tended to be lower in the field compared with the laboratory, whereas bristle and crossvein length heritabilities were similar across environments. There was evidence for heritable variation in wing and bristle traits in both the marginal and more northern populations, suggesting that genetic variation was not limiting in marginal populations. Fluctuating asymmetry (FA) was also assessed as a measure of genomic and environmental stress. There were no consistent differences among populations for the FA of individual traits, or for a total FA score summed across traits. FA levels in field parents and laboratory-reared progeny were similar. Overall, the results do not support the conjecture that levels of phenotypic and genetic variability differ between central and marginal D. serrata populations.
An analysis of G matrix variation in two closely related cricket species, Gryllus firmus and G. pennsylvanicus
Authors: Bégin M. , Roff D. A. 
Published: March 2003

Abstract
An important issue in evolutionary biology is understanding the pattern of G matrix variation in natural populations. We estimated four G matrices based on the morphological traits of two cricket species, Gryllus firmus and G. pennsylvanicus, each reared in two environments. We used three matrix comparison approaches, including the Flury hierarchy, to improve our ability to perceive all aspects of matrix variation. Our results demonstrate that different methods perceive different aspects of the matrices, which suggests that, until more is known about these methods, future studies should use several different statistical approaches. We also found that the differences in G matrices within a species can be larger than the differences between species. We conclude that the expression of the genetic architecture can vary with the environment and that future studies should compare G matrices across several environments. We also conclude that G matrices can be conserved at the level of closely related species.
Evolutionary trade-offs in locomotor capacities in lacertid lizards: are splendid sprinters clumsy climbers?
Authors: Vanhooydonck B. , Van Damme R. 
Published: March 2003

Abstract
We tested the hypothesis that an evolutionary trade-off exists between the capacity to run on level terrain and the ability to climb inclined structures in lacertid lizards. Biomechanical and physiological models of lizard locomotor performance suggest that the morphological design requirements of a ground-dwelling vs. scansorial life style are difficult to reconcile. This conflict is thought to preclude simultaneous evolution of maximal locomotor performance on level and inclined terrain. This notion has been corroborated by comparative studies on lizard species from other groups (Anolis, Chamaeleo, Sceloporus), but is not supported by our data on 13 species from the family Lacertidae. We found no indication of a negative association between maximal sprint speed of lizards over a level racetrack (indicative of ground-dwelling locomotor performance), on an inclined stony surface (indicative of climbing performance over rock faces) and inclined mesh surface (indicative of clambering performance among vegetation). Moreover, morphological characteristics associated with fast sprinting capacities (e.g. long hind limbs) apparently enhance, rather than hinder climbing and clambering performance. We conclude that in our sample of lacertid lizards, the evolution of fast sprinting capacity on level terrain has not inflicted major restrictions on climbing and clambering performance.
Defensive role of leaf trichomes in resistance to herbivorous insects in Datura stramonium
Authors: Valverde P. L. , Fornoni J. , NÚÑez-Farfán J. 
Published: March 2003

Abstract
This study assessed the role of leaf trichome density as a component of resistance to herbivores, in six populations of Datura stramonium. Phenotypic selection on plant resistance was estimated for each population. A common garden experiment was carried out to determine if population differences in leaf trichome density are genetically based. Among population differences in leaf trichome density, relative resistance and fitness were found. Leaf trichome density was strongly positively correlated to resistance across populations. In 5 out of 6 populations, trichome density was related to resistance, and positive directional selection on resistance to herbivores was detected in three populations. Differences among populations in mean leaf trichome density in the common garden suggest genetic differentiation for this character in Datura stramonium. The results are considered in the light of the adaptive role of leaf trichomes as a component of defence to herbivores, and variable selection among populations.
Artificial selection on the shape of reaction norms for eyespot size in the butterfly Bicyclus anynana: direct and correlated responses
Authors: Wijngaarden P. J. , Koch P. B. , Brakefield P. M. 
Published: March 2003

Abstract
The tropical butterfly Bicyclus anynana shows phenotypic plasticity in its ventral wing pattern as an adaptive response to wet-dry seasonality. Wet season form individuals have large eyespots, whereas individuals of the dry season generation have small eyespots. In the laboratory these forms can be obtained by rearing larvae at high and low temperatures, respectively. To study the extent to which the shape of the nearly linear reaction norms for eyespot size can be changed we applied four generations of sib selection by rearing full-sib families across three temperatures. In addition, we measured ecdysteroid titres shortly after pupation in the final generation. Although phenotypic variation in shape was present initially, the experiment yielded lines with reaction norms with similar shapes but different elevations. High, positive genetic correlation across temperatures can explain this lack of response. Differences in ecdysteroid titres did not readily relate to differences in eyespot size.
Do hairworms (Nematomorpha) manipulate the water seeking behaviour of their terrestrial hosts?
Authors: Thomas F. , Schmidt-Rhaesa A. , Martin G. , Manu C. , Durand P. , Renaud F. 
Published: March 2003

Abstract
Several anecdotal reports in the literature have suggested that insects parasitized by hairworms (Nematomorpha) commit `suicide' by jumping into an aquatic environment needed by an adult worm for the continuation of its life cycle. Based on 2 years of observations at a swimming pool in open air, we saw this aberrant behaviour in nine insect species followed by the emergence of hairworms. We conducted field and laboratory experiments in order to compare the behaviour of infected and uninfected individuals of the cricket Nemobius sylvestris. The results clearly indicate that crickets infected by the nematomorph Paragordius tricuspidatus are more likely to jump into water than uninfected ones. The idea that this manipulation involved water detection from long distances by infected insects is not supported. Instead, our observations suggest that infected insects may first display an erratic behaviour which brings them sooner or later close to a stream and then a behavioural change that makes them enter the water.
The significance of wing pattern diversity in the Lycaenidae: mate discrimination by two recently diverged species
Authors: Fordyce J. A. , Nice C. C. , Forister M. L. , Shapiro A. M. 
Published: March 2003

Abstract
Closely related species of lycaenid butterflies are determinable, in part, by subtle differences in wing pattern. We found that female wing patterns can act as an effective mate-recognition signal in some populations of two recently diverged species. In field experiments, we observed that males from a Lycaeides idas population and an alpine population of L. melissa preferentially initiate courtship with conspecific females. A morphometric study indicated that at least two wing pattern elements were important for distinguishing the two species: hindwing spots and orange crescent-shaped pattern elements called aurorae. We deceived male L. idas into initiating courtship with computer generated paper models of heterospecific females when these pattern elements were manipulated, indicating that the wing pattern elements that define the diversity of this group can be effective mate recognition signals.
Phylogeography and colonization history of Lesser Black-backed Gulls (Larus fuscus) as revealed by mtDNA sequences
Authors: Liebers D. , Helbig A. J. 
Published: March 2003

Abstract
Because of the differential amplitude of climatic oscillations, species living at northern latitudes are subject to more frequent and more severe range oscillations than species at southern latitudes. As a consequence, northern populations should, on average, be phylogenetically younger and possess less phylogeographical structure than closely related taxa further south. To test these predictions, we studied the mitochondrial-genetic population structure of NW Palearctic Lesser Black-backed Gulls (Larus fuscus group [=LBBG], five taxa) breeding at temperate to boreal latitudes from Iceland to the Taimyr Peninsula. Results were compared with those previously obtained (Liebers et al. 2001. Mol. Ecol.10: 2447) for more southerly breeding Yellow-legged Gulls (Larus cachinnans group, six taxa from the Atlantic Islands to Mongolia). Sequences of the hypervariable region I (HVR-I) of the mitochondrial control region revealed low within- and between-taxon sequence divergence, little genetic variation, a shallow haplotype phylogeny and poor phylogeographical structure in LBBGs compared with Yellow-legged Gulls. Haplotype frequencies among the five northern taxa formed a stepped cline with significant gene flow restriction between the forms heuglini and fuscus, probably indicating a secondary contact with (partial?) reproductive isolation. Western forms of LBBG, among which mitochondrial gene flow appears unrestricted, show genetic signs of postglacial range expansion and population growth. The Larus fuscus group is derived from a cachinnans-like ancestral population, probably in the Aralo-Caspian basin, and spread from east (NW Siberia) to west within the Palearctic.
Evolution of bite performance in turtles
Authors: Herrel A. , O'Reilly J. C. , Richmond A. M. 
Published: March 2003

Abstract
Among vertebrates, there is often a tight correlation between variation in cranial morphology and diet. Yet, the relationships between morphological characteristics and feeding performance are usually only inferred from biomechanical models. Here, we empirically test whether differences in body dimensions are correlated with bite performance and trophic ecology for a large number of turtle species. A comparative phylogenetic analysis indicates that turtles with carnivorous and durophagous diets are capable of biting harder than species with other diets. This pattern is consistent with the hypothesis that an evolutionary increase in bite performance has allowed certain turtles to consume harder or larger prey. Changes in carapace length tend to be associated with proportional changes in linear head dimensions (no shape change). However, maximum bite force tends to change in proportion to length cubed, rather than length squared, implying that changes in body size are associated with changes in the design of the jaw apparatus. After the effect of body size is accounted for in the analysis, only changes in head height are significantly correlated with changes in bite force. Additionally, our data suggest that the ability to bite hard might trade off with the ability to feed on fast agile prey. Rather than being the direct result of conflicting biomechanical or physiological demands for force and speed, this trade-off may be mediated through the constraints imposed by the need to retract the head into the shell for defensive purposes.
A novel method of behavioural thermoregulation in butterflies
Authors: Kemp D. J. , Krockenberger A. K. 
Published: March 2003

Abstract
The requirement for efficient thermoregulation has directed the coevolution of specialized morphological and behavioural traits in ectotherms. Adult butterflies exhibit three thermoregulatory mechanisms, termed dorsal, lateral and reflectance basking. In this study, we investigate a potential fourth mechanism whereby individuals perch with their wings fully spread and angled downwards such that the margins are appressed to the substrate. We find that mate-locating male Hypolimnas bolina (L.) (Nymphalidae) adopt this posture when operational thoracic temperatures are lowest (less than approximately 34 °C). As thoracic temperature increases, males perch with wings increasingly closed and ultimately select shaded microhabitats. Using thermocouple-implanted dead models, we show that appressed posture individuals warm faster than those adopting the conventional dorsal-basking (horizontal wing) posture. This thermal advantage is not mitigated by shading of the outer 60–70% of the wing area, which suggests that – as with the conventional dorsal posture – only the basal wing surfaces contribute to heat gain via the absorption of solar irradiation. These investigations suggest that appression represents a novel extension of conventional dorsal basking behaviour in butterflies.
Efficacy of a hepatitis C virus core antigen enzyme‐linked immunosorbent assay for the identification of ‘window‐phase’ blood donations
Authors: Lee S. R. , Peterson J. , Niven P. , Bahl C. , Page E. , DeLeys R. , Giordano‐Schmidt D. , Baggett D. , Green G. 
Published: March 2003

Background and ObjectivesRecent studies have suggested that potentially infectious donations provided during the antibody‐negative ‘window’ phase of hepatitis C virus (HCV) infection may be identified by testing for viral RNA or HCV core protein. We therefore evaluated the performance of an HCV antigen enzyme‐linked immunosorbent assay (ELISA) for identification of window‐phase donations and for prospective screening of blood donors.Materials and MethodsOne‐hundred and twenty‐eight archived plasma donations containing HCV RNA, but lacking antibody to HCV (anti‐HCV), were tested by using the HCV antigen ELISA, together with 9951 freshly collected serum and plasma specimens from blood donors.ResultsHCV core antigen was detected in 94% (120/128) of window‐phase plasma donations. Overall specificity in freshly collected blood donor specimens was 99·74%. Two putative window‐phase donations containing HCV core protein and viral RNA were identified from paid plasma donors by prospective testing with the HCV antigen ELISA.ConclusionThese results indicate that an HCV antigen ELISA can identify almost all (94%) of viraemic donations given during the seronegative window phase of infection. The performance of the HCV antigen ELISA appears to be suitable for large‐scale screening of blood donations.
Automated serological compatibility testing using a solid‐phase test and standard laboratory equipment
Authors: Ostendorf N. , Niefhoff D. , Cassens U. , Sibrowski W. 
Published: March 2003

Background and ObjectivesTo prove the feasibility of a semi‐automated cross‐match procedure using a commercially available solid‐phase microplate test and standard laboratory equipment.Material and MethodsThe new procedure was evaluated against the conventional spin tube technique and the gel centrifugation system.ResultsThe sensitivity of the method and the rate of non‐specific reactions were equal to those for the other test systems. The samples taken from the red cell concentrates for cross‐matching remained stable for the shelf‐life of the product.ConclusionThe semi‐automated cross‐match was successfully introduced in our routine laboratory as a means to process large numbers of tests.
Autologous blood donation and transfusion in Europe
Authors: Politis C. , Richardson C. 
Published: March 2003

Background and ObjectivesThe aim of this study was to record practices in autologous blood transfusion in Europe in 1997.Materials and MethodsA questionnaire mainly about predeposit was distributed to the National Representatives of all 41 member states of the Council of Europe’s Committee of Experts on Blood Transfusion and Haematology. Replies were received from 29.Results and ConclusionAutologous blood units collected in 1997 amounted to 4·2% of the allogeneic units, with wide variations between countries. Predeposit was used most frequently in Italy (8·9%), Germany (7·1%) and France (6·6%). Some countries, notably Scandinavia, do not encourage predeposit, chiefly on the grounds that it is not cost‐effective, but others are promoting its use.
Development of multiplexed nucleic acid testing for human immunodeficiency virus type 1 and hepatitis C virus
Authors: Cleland A. , Davis C. , Adams N. , Lycett C. , Jarvis L. M. , Holmes H. , Simmonds P. 
Published: March 2003

Background and ObjectivesIn most Western countries, blood donations are routinely screened for hepatitis C virus (HCV) RNA by polymerase chain reaction (PCR) or other nucleic acid tests. We describe the development of a multiplexed assay for human immunodeficiency virus type 1 (HIV‐1) and HCV in an internally controlled PCR suitable for large‐scale blood donor screening.Materials and MethodsThe HIV/HCV multiplexed PCR used primers from highly conserved regions in the long terminal repeat region. The National Institute for Biological Standards and Controls (NIBSC) International HIV‐1 RNA standard, run control and HIV‐1 subtype panel were used for assay evaluation.ResultsThe HIV‐1 PCR showed a sensitivity of 24 IU/ml for HIV‐1 RNA (a dilution where 95% of replicate reactions were positive), which was at least five times more sensitive than the Roche Monitor version 1·5 (using the ultrasensitive extraction protocol) and Organon NASBA assays. The assay was capable of detecting all subtypes of HIV‐1 (A to H), as well as the more divergent group N and O variants. The sensitivity of the PCR was unaffected by multiplexing with HCV primers and by the presence of a bovine viral diarrhoea virus (BVDV) internal control.ConclusionWe have developed a highly sensitive multiplexed PCR for HIV‐1 and HCV RNA screening that can be introduced into current PCR‐based blood donor screening at minimal cost and without significant operational changes.
Loss of phosphotyrosine phosphatase activity and changes in the tyrosine phosphorylation state of proteins after storage of sheep platelets in plasma or Seto solution at 4 °C
Authors: Hernández‐Hernández A. , Sánchez‐Bernal C. , Rodríguez M. C. , Gómez F. P. , Llanillo M. , Sánchez‐Yagüe J. 
Published: March 2003

Background and ObjectivesDuring platelet storage an array of deleterious changes occur, through mechanisms not fully understood, which impair platelet haemostasis. Transfused platelets should maintain the integrated networks of signalling pathways that regulate platelet activation and functionality. We hypothesized that protein phosphorylation and dephosphorylation, which play a fundamental role in these pathways, might be affected by platelet storage. We therefore investigated whether the activity of phosphotyrosine phosphatase (PTP), which belongs to an oxidant‐susceptible group of enzymes involved in the platelet signal‐transduction pathways that ensure platelet functionality, is affected by platelet storage.Materials and MethodsUsing sheep platelet species as a model system, we conducted serial studies on the membranes of platelets and microparticles shed during platelet storage, in their own plasma or in a synthetic medium called Seto, for up to 5 days at 4 °C.ResultsA progressive decrease in both total and specific membrane‐associated PTP activities from whole platelets (but not from microparticles) located within each platelet storage bag was observed from day 1 onwards in both types of storage media. These decreases could be partly avoided by the addition of vitamin E. Additionally, the observed decrease in PTP activity was accompanied with increases in the tyrosine phosphorylation of proteins from whole platelets or crude platelet membranes, the tyrosine phosphorylation state of proteins from microparticles remaining basically unchanged.ConclusionOur findings suggest that alterations of at least the tyrosine phosphorylation balance might be one of the reasons for the decrease in the haemostatic function of stored platelets.
DNA profiling: a valuable tool for quality control of sample logistics including occurrences of suspected sample confusion in a blood donation centre
Authors: Glock B. , Reisacher R. B. K. , Schöck M. A. , Rogado J. , Feinböck C. , Eschner G. , Eder E. , Mayr W. R. 
Published: March 2003

Background and Objectives A molecular method for analysing whole‐blood samples should be established for quality control of plasma sample logistics.Materials and Methods DNA profiles of retention samples (plasma) were compared to profiles of recent donations (whole blood). DNA extraction, amplification and detection were performed using the Qiagen DNA Blood Mini kit, the AmpFFISTR Profiler Plus Kit and capillary electrophoresis, respectively.Results Matched pairs of full profiles were obtained for all samples investigated, therefore no deviation from the standardized procedures was detected.Conclusions Modified extraction and amplification protocols enabled DNA profiling to be used for the quality control of plasma samples. Hence, DNA profiling can be used in the blood bank as a safe and easy method for quality control of sample logistics.