bluuebunny/crossref_metadata_2025_split huggingface dataset:
Direct and correlated responses to artificial selection on male mating frequency in the stalk‐eyed fly Cyrtodiopsis dalmanni
Authors: ROGERS D. W. , BAKER R. H. , CHAPMAN T. , DENNIFF M. , POMIANKOWSKI A. , FOWLER K. 
Published: April 2005

AbstractTraditionally it was thought that fitness‐related traits such as male mating frequency, with a history of strong directional selection, should have little additive genetic variance and thus respond asymmetrically to bidirectional artificial selection. However, recent findings and theory suggest that a balance between selection for increased male mating frequency and opposing selection pressures on physiologically linked traits will cause male mating frequency to have high additive genetic variation and hence respond symmetrically to selection. We tested these hypotheses in the stalk‐eyed fly, Cyrtodiopsis dalmanni, in which males hold harems comprising many females and so have the opportunity to mate at extremely high frequencies. We subjected male stalk‐eyed flies to artificial selection for increased (‘high’) and decreased (‘low’) mating frequency in the presence of ecologically realistic, high numbers of females. High line males mated significantly more often than control or low line males. The direct response to selection was approximately symmetric in the high and low lines, revealing high additive genetic variation for, and no significant genetic constraints on, increased male mating frequency in C. dalmanni. In order to investigate trade‐offs that might constrain male mating frequency under natural conditions we examined correlated responses to artificial selection. We measured accessory gland length, testis length and eyespan after 7 and 14 generations of selection. High line males had significantly larger accessory glands than low line males. No consistent correlated responses to selection were found in testis length or eyespan. Our results suggest that costs associated with the production and maintenance of large accessory glands, although yet to be identified, are likely to be a major constraint on mating frequency in natural populations of C. dalmanni.
Adaptive evolution in GroEL from distantly related endosymbiotic bacteria of insects
Authors: FARES M. A. , MOYA A. , BARRIO E. 
Published: April 2005

AbstractMany symbioses between bacteria and insects resulted from ancient infections followed by strict vertical transmission within host lineages. The strong bottlenecks under which this transmission occurs promote the neutral fixation of slightly deleterious mutations by genetic drift. As predicted by Muller's ratchet, this fixation will drive endosymbiotic bacteria through an irreversible dynamics of fitness loss. The chaperonin GroEL has been proposed as a compensatory mechanism whereby endosymbiotic bacteria of aphids persist. Here, we show that endosymbiotic bacteria of insects from two phylogenetically very distant bacterial phyla have fixed amino acid substitutions by positive selection in functionally important GroEL regions involved in either GroES/peptide binding or in the en bloc movement of the GroEL apical domain. These results, together with the high levels of constitutive expression of GroEL in these endosymbionts, provide valuable insights into the evolution of a molecular mechanism responsible for the maintenance of the symbiotic lifestyle.
Lower fecundity in parthenogenetic geckos than sexual relatives in the Australian arid zone
Authors: KEARNEY M. , SHINE R. 
Published: April 2005

AbstractTheoretical models of the advantage of sexual reproduction typically assume that reproductive output is equal in sexual and parthenogenetic females. We tested this assumption by comparing fecundity between parthenogenetic and sexual races of gekkonid lizards in the Heteronotia binoei complex, collected across a 1200 km latitudinal gradient through the Australian arid zone. Under laboratory conditions, parthenogenetic geckos had approximately 30% lower fecundity when compared with their sexual progenitors, irrespective of body size. Reflecting clutch‐size constraints in gekkonids, this fecundity difference was mainly because of fewer clutches over a shorter period. When parthenogens were compared more broadly with all coexisting sexual races across the latitudinal gradient, parthenogens had lower fecundity than sexuals only when corrected for body size. Differences in fecundity between parthenogens and coexisting sexual races depended on which sexual race was considered. There was no significant relationship between fecundity and parasite (mite) load, despite significantly higher mite loads in parthenogens than in sexual races.
Direct and indirect assortative mating: a multivariate approach to plant flowering schedules
Authors: WEIS ARTHUR E. 
Published: April 2005

AbstractThis paper develops methods to partition the phenotypic correlation between mates for a focal trait – the standard measure for assortative mating – into a direct component and additional indirect components. Indirect assortative mating occurs when a nonassorting trait is correlated within individuals to a directly assorting trait. Direct and indirect assortative mating is assessed for flowering phenology in Brassica rapa. The flowering time of pollen recipients (mothers) was strongly correlated (ρ = 0.67) to that of potential pollen donors (fathers). Similarly, recipients and donors were correlated for duration of their flowering periods (ρ = 0.32) and stem diameters (ρ = 0.52). A partitioning of between‐mate correlations revealed direct assortative mating for flowering time and period duration. However, assortment for stem diameter is explained solely through its correlation to flowering time. Examination of standard quantitative genetic theory shows that indirect assortative mating inflates genetic variance in a focal trait and the genetic covariance between focal and phenotypically correlated traits.
Lectin Histochemical Investigations of the Distal Gut of Chicks with Special Emphasis on the Follicle‐associated Epithelium
Authors: Pohlmeyer I. , Jörns J. , Schumacher U. , Van Damme E. J. M. , Peumans W. J. , Pfüller U. , Neumann U. 
Published: April 2005

SummaryCarbohydrates on epithelial cell surfaces play an important role as attachment sites for different microorganisms like bacteria, viruses and protozoa. To obtain more information about the distribution of carbohydrates on the luminal surface along the intestine, lectin histochemical studies on different gut segments of chicks of different age groups were carried out using a panel of 13 lectins with specificities for Man, Glc, Gal, GalNAc, GlcNAc or GlcNAc oligosaccharides and Sia. Furthermore, we tried to find out whether previously reported specificities of certain lectins for M cells (membranous or multifold cells) in the bursa of Fabricius (BF) can be observed also on M cells of the intestine. As a result we were able to demonstrate binding of all lectins employed in these studies in all investigated gut segments. In some cases, the application of the same lectin led to varying staining intensities of the same histological structures in different age‐groups (e.g. staining of the brush border with WGA, LEA, MAA or Conarva) or different gut segments (e.g. staining of goblet cells with CMA II, LEA and MPA). Hence, terminal carbohydrate residues of glycoconjugates on the intestinal epithelium vary depending on age and organ site. As glycoconjugates can act as attachment sites for microorganisms, these differences in the distribution of sugar residues may be one explanation for the site‐specificity of certain pathogens. Furthermore, the binding of lectins to the follicle‐associated epithelium (FAE) of the BF differs from that to the FAE of the intestine again stressing the site specificity of lectin binding. Thus, up to now no universal M‐cell marker along the chicken intestine exists.
Biochemical Intestinal Parameters in Germ‐free Minipigs and Rats and in Ex‐germ‐free Minipigs and Rats Monoassociated with Escherichia coli
Authors: Cardona M. E. , Kozakova H. , Collinder E. , Persson A.‐K. , Midtvedt T. , Norin E. 
Published: April 2005

SummaryIntestinal contents of newborn and young germ‐free minipigs and germ‐free rats were investigated for the following biochemical parameters – conversion of cholesterol to coprostanol, degradation of β‐aspartylglycine, level of tryptic activity, formation of urobilinogen and the profile of short‐chain fatty acids. Additionally, germ‐free minipigs and germ‐free rats were monoassociated with non‐pathogenic strains of Escherichia coli and were investigated for the same biochemical parameters. The conversion of cholesterol to coprostanol, degradation of β‐aspartylglycine, tryptic activity and the short‐chain fatty acid profile were similar to those found in previous studies in germ‐free animals. Slightly higher amounts of urobilinogen than in the other species investigated so far were found in samples from germ‐free and monoassociated minipigs. Except for the total amount of short‐chain fatty acids in rats, monoassociation with E. coli did not alter any of the parameters either in the minipigs or in the rats.
Immunohistochemical Demonstration of Connexin‐Related Epithelization Defects in a Lamb Caused by (Erythro)keratodermia Variabilis
Authors: Meyer W. , Wehrend A. , Schnapper A. , Bostedt H. 
Published: April 2005

SummaryThe distribution of four important connexins (Cx 26, 30, 31, 43) in the skin of a neonatal lamb with (erythro)keratodermia (EKV) was demonstrated using immunohistochemistry, including a very sensitive visualization system. The reaction staining for Cx 26, 30 and 31 was negative to weak in all skin structures, and only Cx 43 displayed weak to moderate positive reactions, although not uniformly distributed throughout the important systems (e.g. epidermis, hair follicle sheaths). Thus, the study proves for the first time that connexin defects are associated with the development of EKV in domesticated mammals, as they are in humans.
Disseminated Acute Concomitant Aspergillosis and Mucormycosis in a Pony
Authors: Thirion‐Delalande C. , Guillot J. , Jensen H. E. , Crespeau F. L. , Bernex F. 
Published: April 2005

SummaryA 6‐year‐old female pony died after 2 days of prostration. Clinical signs included hyperthermia and abnormal pulmonary auscultation sounds. Necropsy revealed diffuse severe necrohaemorrhagic colitis and splenitis, multiple visceral ecchymoses, petechial haemorrhages in the brain and lungs. Microscopical examination showed acute necrohaemorrhagic colitis, encephalitis, pneumonia and splenitis associated with fibrinoid vasculitis, thrombosis and fungal hyphae within and around vessels. Immunohistologically, concomitant aspergillosis (caused byAspergillus fumigatus) and mucormycosis (causde byAbsidia corymbifera) were identified in the colonic and pulmonary lesions, whereas pure mucormycosis was observed in cerebral and splenic lesions. Dual mycotic infections are very rarely described, and the present case emphasizes the need of immunohistochemistry in order to obtain a clear‐cut diagnosis of mixed fungal infections.
Serum Osteocalcin and CTX‐MMP Concentration in Young Exercising Thoroughbred Racehorses
Authors: Carstanjen B. , Amory H. , Sulon J. , Hars O. , Remy B. , Langlois P. , Lepage O. M. 
Published: April 2005

SummaryBone responds to exercise with changes in bone (re‐)modelling, which might be monitored non‐invasively with biochemical bone markers. The aim of this study was to evaluate the influence of exercise on serum osteocalcin and serum carboxy‐terminal cross‐linked telopeptide of type I collagen generated by matrix metalloproteinases (CTX‐MMP) concentration in young racehorses. Seventy‐one 2 to 4‐year‐old Thoroughbreds were included in this prospective infield study. Blood sampling was performed six times (i.e. six sampling cycles) during a 9‐month period. Serum samples were analysed with commercial osteocalcin and CTX‐MMP radioimmunoassays. Two‐year‐old racehorses had higher serum osteocalcin and CTX‐MMP values than 3‐year‐old horses. Gender and training amplitude did not significantly influence serum osteocalcin and CTX‐MMP values. Two‐year‐old horses showed an increase in osteocalcin values between cycles 2 and 3 and an increase in serum CTX‐MMP values between cycles 1 and 2. Serum osteocalcin and CTX‐MMP concentrations decreased between cycles 4 and 5, and 5 and 6. Three‐year‐old horses showed an increase in serum osteocalcin levels between cycles 3 and 4 and an increase in serum CTX‐MMP concentrations between cycles 1 and 2, and 3 and 4. Serum osteocalcin levels decreased between cycles 5 and 6, whereas serum CTX‐MMP levels decreased between cycles 4 and 5, and 5 and 6. Two‐ and three‐year‐old horses showed a decreased osteocalcin/CTX‐MMP ratio between cycles 1 and 2. Moreover, 2‐year‐old horses showed an increase in the osteocalcin/CTX‐MMP ratio between cycles 2 and 3. Sore shin formation did not significantly influence serum osteocalcin and CTX‐MMP values. Serum osteocalcin and CTX‐MMP are promising bone markers for monitoring exercise induced changes in equine bone metabolism.
The dynamics of spatially coupled food webs
Authors: McCann K. S. , Rasmussen J. B. , Umbanhowar J. 
Published: April 2005

AbstractThe dynamics of ecological systems include a bewildering number of biotic interactions that unfold over a vast range of spatial scales. Here, employing simple and general empirical arguments concerning the nature of movement, trophic position and behaviour we outline a general theory concerning the role of space and food web structure on food web stability. We argue that consumers link food webs in space and that this spatial structure combined with relatively rapid behavioural responses by consumers can strongly influence the dynamics of food webs. Employing simple spatially implicit food web models, we show that large mobile consumers are inordinately important in determining the stability, or lack of it, in ecosystems. More specifically, this theory suggests that mobile higher order organisms are potent stabilizers when embedded in a variable, and expansive spatial structure. However, when space is compressed and higher order consumers strongly couple local habitats then mobile consumers can have an inordinate destabilizing effect. Preliminary empirical arguments show consistency with this general theory.
Forest turnover rates follow global and regional patterns of productivity
Authors: Stephenson Nathan L. , van Mantgem Phillip J. 
Published: April 2005

AbstractUsing a global database, we found that forest turnover rates (the average of tree mortality and recruitment rates) parallel broad‐scale patterns of net primary productivity. First, forest turnover was higher in tropical than in temperate forests. Second, as recently demonstrated by others, Amazonian forest turnover was higher on fertile than infertile soils. Third, within temperate latitudes, turnover was highest in angiosperm forests, intermediate in mixed forests, and lowest in gymnosperm forests. Finally, within a single forest physiognomic type, turnover declined sharply with elevation (hence with temperature). These patterns of turnover in populations of trees are broadly similar to the patterns of turnover in populations of plant organs (leaves and roots) found in other studies. Our findings suggest a link between forest mass balance and the population dynamics of trees, and have implications for understanding and predicting the effects of environmental changes on forest structure and terrestrial carbon dynamics.
Ecology of invasive mosquitoes: effects on resident species and on human health
Authors: Juliano Steven A. , Philip Lounibos L. 
Published: April 2005

AbstractInvestigations of biological invasions focus on patterns and processes that are related to introduction, establishment, spread and impacts of introduced species. This review focuses on the ecological interactions operating during invasions by the most prominent group of insect vectors of disease, mosquitoes. First, we review characteristics of non‐native mosquito species that have established viable populations, and those invasive species that have spread widely and had major impacts, testing whether biotic characteristics are associated with the transition from established non‐native to invasive. Second, we review the roles of interspecific competition, apparent competition, predation, intraguild predation and climatic limitation as causes of impacts on residents or as barriers to invasion. We concentrate on the best‐studied invasive mosquito, Aedes albopictus, evaluating the application of basic ecological theory to invasions by Aedes albopictus. We develop a model based on observations of Aedes albopictus for effects of resource competition and predation as barriers to invasion, evaluating which community and ecosystem characteristics favour invasion. Third, we evaluate the ways in which invasive mosquitoes have contributed to outbreaks of human and animal disease, considering specifically whether invasive mosquitoes create novel health threats, or modify disease transmission for existing pathogen–host systems.
Phylogenetic position of Nerillidae and Aberranta (Polychaeta, Annelida), analysed by direct optimization of combined molecular and morphological data
Authors: Worsaae Katrine , Nygren Arne , Rouse Greg W. , Giribet Gonzalo , Persson Jenny , Sundberg Per , Pleijel Fredrik 
Published: April 2005

The phylogenetic position of the most speciose meiofaunal polychaete family, Nerillidae, has remained contentious. Recent hypotheses have generally focused on the fact that Nerillidae shares with Aciculata (a major polychaete subgroup) features such as compound chaetae, ventral buccal organ and short ventrolateral palps. Here we present the first phylogenetic analysis of Aciculata, together with Nerillidae, combining morphological and molecular data. We also include Aberrantidae, previously referred to or placed near to spiomorph polychaetes, but recently referred to Aciculata, possibly close to Nerillidae. The data sets of 24 terminals contain 53 morphological characters and nearly complete sequences of 18S rRNA. The sequences were analysed simultaneously with the morphological data by direct optimization in the program POY with a variety of parameter settings (costs of gaps: transversions: transitions). The various settings resulted in markedly different phylogenetic hypotheses, but on the basis of congruence (ILD) the results of two parameter settings were chosen. In all analyses, the three included nerillid species constituted a monophyletic group. Only two analyses provided fully resolved cladograms. The morphological analysis gave poor resolution and the position of the nerillids was equivocal. The two molecular‐based cladograms (minimizing ILD) were also poorly resolved, but one provided a position for nerillids next to Eunice pennata and Nothria conchilega, from the subgroup Eunicida within Aciculata. The two cladograms of the combined analyses (minimizing ILD) were fully resolved and placed nerillids in a terminal position next to Aberranta sp., within a clade of eunicidan species. The study showed that the analytical conditions for the homology assignment of 18S rRNA strongly influenced the phylogenetic results. The various previous proposals on the phylogenetic position of the Nerillidae are reviewed, some of which are in accordance with the results of the present study.
Phylogenetic revision of the spider genus Negayan (Araneae, Anyphaenidae, Amaurobioidinae)
Authors: Lopardo Lara 
Published: April 2005

A taxonomic revision and phylogenetic analysis of the spider genus Negayan Ramírez, 2003 (Anyphaenidae, Amaurobioidinae, Amaurobioidini) is presented. All 12 known species of Negayan plus representatives of each of the other nine amaurobioidini genera (25 taxa in total) were scored for 134 morphological characters. The cladistic analysis of this matrix results in a single most parsimonious tree (LE = 382; CI = 0.42; CI for informative characters = 0.36; RI = 0.49). The monophyly of Negayan is corroborated, although with low support values. My results correspond to those of a previous study, with N. paduana as the basal species of the genus and Selknamia as the sister‐group of Negayan. Negayan is diagnosed by the genitalic morphology in both sexes. Males of Negayan have a characteristic retrolateral tibial apophysis on palps that is long, thick and sinuous at the tip. Females of Negayan have a characteristic genitalic pattern with coiled copulatory ducts and contiguous spermathecae. New diagnostic characters are proposed. The genus Negayan comprises 12 species, four of them known only from females. It is known from Argentina, Chile and Peru. Eight new species are described here: N. puno sp. nov., N. cerronegro sp. nov., N. tata sp. nov., N. ancha sp. nov., N. enrollada sp. nov., N. tucuman sp. nov., N. tarapaca sp. nov., and N. argentina sp. nov. New morphological data are added to the descriptions of N. tridentata (Simon), N. paduana (Karsch) and N. coccinea (Mello‐Leitão). The male of N. excepta (Tullgren) is described for the first time and the female is redescribed. Negayan tridentata is a senior synonym of Gayenna exigua (Mello‐Leitão); and N. paduana is a senior synonym of Tomopisthes lebruni (Simon).
Genetic association study of adiponectin polymorphisms with risk of Type 2 diabetes mellitus in Korean population
Authors: Lee Y. Y. , Lee N. S. , Cho Y. M. , Moon M. K. , Jung H. S. , Park Y. J. , Park H. J. , Youn B. S. , Lee H. K. , Park K. S. , Shin H. D. 
Published: April 2005

AbstractAims  To investigate any association between Type 2 diabetes mellitus and two single nucleotide polymorphisms (SNPs) in the adiponectin gene, T45G and G276T, in the Korean population.Methods  We genotyped 427 non‐diabetic controls and 493 Type 2 diabetic patients for SNPs T45G and G276T of adiponectin gene, measured plasma adiponectin concentrations, and examined clinical parameters in Koreans.Results  There were no statistically significant differences in allele frequencies of SNPs 45 and 276 comparing control with Type 2 diabetic subjects (T frequency 68.3% vs. 71.6%, P = 0.13 for SNP45, G frequency 72.2% vs. 68.9%, P = 0.12 for SNP276). The genotype distributions of these SNPs had no association with the risk of Type 2 diabetes and metabolic parameters of insulin resistance. Plasma levels of adiponectin were not statistically different according to T45G and G276T either, in both control and Type 2 diabetic subjects.Conclusion  The T45G and G276T of the adiponectin gene may not be an important determinant of Type 2 diabetes or insulin resistance in Korean subjects.