bluuebunny/crossref_metadata_2025_split huggingface dataset:
Downregulation of the nuclear‐encoded subunits of the complexes III and IV disrupts their respective complexes but not complex I in procyclic Trypanosoma brucei
Authors: Horváth Anton , Horáková Eva , Dunajčíková Petra , Verner Zdeněk , Pravdová Eliška , Šlapetová Iveta , Cuninková L’udmila , Lukeš Julius 
Published: August 2005

SummaryThe function, stability and mutual interactions of selected nuclear‐encoded subunits of respiratory complexes III and IV were studied in the Trypanosoma brucei procyclics using RNA interference (RNAi). The growth rates and oxygen consumption of clonal cell lines of knock‐downs for apocytochrome c1 (apoc1) and the Rieske Fe‐S protein (Rieske) of complex III, and cytochrome c oxidase subunit 6 (cox6) of complex IV were markedly decreased after RNAi induction. Western analysis of mitochondrial lysates using specific antibodies confirmed complete elimination of the targeted proteins 4–6 days after induction. The Rieske protein was reduced in the apoc1 knock‐down and vice versa, indicating a mutual interdependence of these components of complex III. However, another subunit of complex IV remained at the wild‐type level in the cox6 knock‐down. As revealed by two‐dimensional blue native/SDS‐PAGE electrophoresis, silencing of a single subunit resulted in the disruption of the respective complex, while the other complex remained unaffected. Membrane potential was reproducibly decreased in the knock‐downs and the activities of complex III and/or IV, but not complex I, were drastically reduced, as measured by activity assays and histochemical staining. Using specific inhibitors, we have shown that in procyclics with depleted subunits of the respiratory complexes the flow of electrons was partially re‐directed to the alternative oxidase. The apparent absence in T. brucei procyclics of a supercomplex composed of complexes I and III may represent an ancestral state of the respiratory chain.
Novel lipopolysaccharide biosynthetic genes containing tetranucleotide repeats in Haemophilus influenzae, identification of a gene for adding O‐acetyl groups
Authors: Fox Kate L. , Yildirim Håkan H. , Deadman Mary E. , Schweda Elke K. H. , Moxon E. Richard , Hood Derek W. 
Published: August 2005

SummaryMany of the genes for lipopolysaccharide (LPS) biosynthesis in Haemophilus influenzae are phase variable. The mechanism of this variable expression involves slippage of tetranucleotide repeats located within the reading frame of these genes. Based on this, we hypothesized that tetranucleotide repeat sequences might be used to identify as yet unrecognized LPS biosynthetic genes. Synthetic oligonucleotides (20 bases), representing all previously reported LPS‐related tetranucleotide repeat sequences in H. influenzae, were used to probe a collection of 25 genetically and epidemiologically diverse strains of non‐typeable H. influenzae. A novel gene identified through this strategy was a homologue of oafA, a putative O‐antigen LPS acetylase of Salmonella typhimurium, that was present in all 25 non‐typeable H. influenzae, 19 of which contained multiple copies of the tetranucleotide 5′‐GCAA. Using lacZ fusions, we showed that these tetranucleotide repeats could mediate phase variation of this gene. Structural analysis of LPS showed that a major site of acetylation was the distal heptose (HepIII) of the LPS inner‐core. An oafA deletion mutant showed absence of O‐acetylation of HepIII. When compared with wild type, oafA mutants displayed increased susceptibility to complement‐mediated killing by human serum, evidence that O‐acetylation of LPS facilitates resistance to host immune clearance mechanisms. These results provide genetic and structural evidence that H. influenzae oafA is required for phase variable O‐acetylation of LPS and functional evidence to support the role of O‐acetylation of LPS in pathogenesis.
Characterization of the 26S rRNA‐binding domain in Saccharomyces cerevisiae ribosomal stalk phosphoprotein P0
Authors: Santos Cruz , Ballesta Juan P. G. 
Published: August 2005

SummaryThe stalk is a universal structure of the large ribosomal subunit involved in the function of translation factors. The bacterial stalk is highly stable but its stability is notably reduced in eukaryotes, favouring a translation regulatory activity of this ribosomal domain, which has not been reported in prokaryotes. The RNA‐binding protein P0 plays a key role in determining the eukaryotic stalk activities, and characterization of the P0/RNA interaction is essential to understand the evolutionary process. Using a series of Saccharomyces cerevisiae‐truncated proteins, a direct involvement of two N‐terminal regions, I3‐M58 and K81‐V121, in the interaction of P0 with the ribosome has been shown. Two other conserved regions, R122‐T149 and G162‐T182, affect P0 interaction with other stalk components and the sensitivity to sordarin anti‐fungals but are not essential for RNA binding. Moreover, P0 and a P0 fragment comprising only the first 121 amino acids show a similar in vitro affinity for the highly conserved 26S rRNA binding site. A protein chimera containing the first 165 amino acids of L10, the P0 bacterial counterpart, is able to complement the absence of P0 and also shows the same P0 RNA binding characteristics. Altogether, the results indicate that the affinity of the stalk RNA‐binding protein for its substrate has been highly conserved, and changes in the stability of the interaction of P0 with the ribosome, which are essential for the new eukaryotic functions, result from the evolution of the overall stalk structure.
Zebra dolomitization as a result of focused fluid flow in the Rocky Mountains Fold and Thrust Belt, Canada
Authors: VANDEGINSTE VEERLE , SWENNEN RUDY , GLEESON SARAH A. , ELLAM ROB M. , OSADETZ KIRK , ROURE FRANÇOIS 
Published: August 2005

AbstractDiscordant zebra dolomite bodies occur locally in the Middle Cambrian Cathedral and Eldon Formations of the Main Ranges of the Canadian Rocky Mountains Fold and Thrust Belt. They are characterized by alternating dark grey (a) and white (b) bands, forming an ‘abba’ diagenetic cyclicity. These bands developed parallel to both bedding and cleavage. Dark grey (a) bands consist of fine (< 300 μm) non‐planar crystalline impure dolomite. The white (b) bands are composed of coarse (up to several millimetres) milky‐white pure saddle dolomites (b1) which are often covered by pore‐lining zoned dolomite (b2). Thebphases often possess a saddle‐shaped morphology. In contrast to the replacement origin of theadolomite, the zonedb2dolomite rims are interpreted as a cement formed in open cavities. Theb1dolomite is interpreted as the result of recrystallization with diagenetic leaching of non‐carbonate components.All the zebra dolomites studied are (nearly) stoichiometric and are characterized by enriched Na and depleted Sr concentrations. Fe and Mn concentrations in these dolomites differ depending on the sample locality. Fluid inclusion data indicate that the dolomites formed from relatively hot (TH = 130–200 °C), saline (20–23 wt% CaCl2eq.) fluids. A diagenetic high temperature origin is also supported by depletedδ18O values (−20 to −14‰ VPDB). A contribution of87Sr‐enriched fluids is reflected in the87Sr/86Sr values (0·7091–0·7123).Zebra dolomite development is explained by focused fluid flow, which exploited areas of structural weaknesses (e.g. basin‐platform, rim areas, faults, etc.). Expulsion of hot basinal brines in a tectonically active regime generated overpressures, which explains the development of secondary porosity during zebra dolomitization as well as the intra‐zebra fracturing at decimetre to micrometre scale.
A genetic map ofCottus gobio(Pisces, Teleostei) based on microsatellites can be linked to the physical map ofTetraodon nigroviridis
Authors: STEMSHORN K. C. , NOLTE A. W. , TAUTZ D. 
Published: August 2005

AbstractTo initiate QTL studies in the nonmodel fishCottus gobiowe constructed a genetic map based on 171 microsatellite markers. The mapping panel consisted ofF1intercrosses between two divergentCottuslineages from the River Rhine System. Basic local alignment search tool (BLAST) searches with the flanking sequences of the microsatellite markers yielded a significant (e < 10−5) hit with theTetraodon nigroviridisgenomic sequence for 45% of theCottusloci. Remarkably, most of these hits were due to short highly conserved noncoding stretches. These have an average length of 40 bp and are on average 92% conserved. Comparison of the map locations between the two genomes revealed extensive conserved synteny, suggesting that theTetraodongenomic sequence will serve as an excellent genomic reference for at least the Acanthopterygii, which include evolutionarily interesting fish groups such as guppies (Poecilia), cichlids (Tilapia) orXiphophorus(Platy). The apparent high density of short conserved noncoding stretches in these fish genomes will highly facilitate the identification of genes that have been identified in QTL mapping strategies of evolutionary relevant traits.
Hybridization dynamics between sympatric species of trout: loss of reproductive isolation
Authors: BETTLES C. M. , DOCKER M. F. , DUFOUR B. , HEATH D. D. 
Published: August 2005

AbstractAlthough reinforcement should enhance reproductive barriers in sympatric species, sympatric trout species do hybridize. Using mitochondrial and nuclear species markers, we investigated hybridization directionality, hybrid mating biases, and selection against hybrids in 13 sympatric cutthroat and rainbow trout populations on Vancouver Island, Canada. Approximately 50% of the genotyped fish were hybrid (F1 or higher‐order) and populations ranged from very recent (all F1 hybrids) to extremely advanced higher‐order hybridization. Overall, interbreeding was reciprocal, although some populations showed directional hybridization. Pronounced cytonuclear disequilibrium in post‐F1 hybrids indicated a remarkable mating bias not previously reported, which is most likely because of behavioural reproductive preferences. Selection against hybrids was observed in only two populations, indicative of extrinsic selection. Two populations were ‘hybrid swarms’, with a complete loss of reproductive isolation. The complex hybridization dynamics in this system represent a valuable natural experiment of the genetic and evolutionary implications of recent and on‐going interspecific hybridization.
Pollinating fig waSPS: genetic consequences of island recolonization
Authors: ZAVODNA MONIKA , ARENS PAUL , VAN DIJK PETER J. , PARTOMIHARDJO TUKIRIN , VOSMAN BEN , VAN DAMME JOS M. M. 
Published: August 2005

AbstractThe levels of genetic diversity and gene flow may influence the long‐term persistence of populations. Using microsatellite markers, we investigated genetic diversity and genetic differentiation in island (Krakatau archipelago, Indonesia) and mainland (Java and Sumatra, Indonesia) populations of Liporrhopalum tentacularis and Ceratosolen bisulcatus, the fig wasp pollinators of two dioecious Ficus (fig tree) species. Genetic diversity in Krakatau archipelago populations was similar to that found on the mainland. Population differentiation between mainland coastal sites and the Krakatau islands was weak in both wasp species, indicating that the intervening 40 km across open sea may not be a barrier for wasp gene flow (dispersal) and colonization of the islands. Surprisingly, mainland populations of the fig waSPS may be more genetically isolated than the islands, as gene flow between populations on the Javan mainland differed between the two wasp species. Contrasting growth forms and relative ‘immunity’ to the effects of deforestation in their host fig trees may account for these differences.
Sexual conflict and female immune suppression in the cricket, Allonemobious socius
Authors: FEDORKA KENNETH M. , ZUK MARLENE 
Published: August 2005

AbstractIn many animal systems, females exhibit a localized immune response to insemination that helps defend against sexually transmitted disease. However, this response may also kill sperm, reducing a male's reproductive potential. If males could suppress this response, they may be able to increase their sperm's representation in the female's reproductive tract, thereby increasing their fitness. Here we address the hypothesis that, under conditions of sperm competition, males interfere with female immunity. To test our hypothesis, we manipulated levels of female mating frequency (single vs. multiply mated) and seminal diversity (monandrous vs. polyandrous) in the cricket, Allonemobius socius and measured female immune response. As mating frequency increased, female hemocyte load decreased, indicating a general reproductive cost. As seminal diversity increased, phenoloxidase (PO) activity (in vitro measure of ‘potential’ macroparasitic defense) increased and encapsulation ability (in vivo measure of ‘realized’ macroparasitic defense) decreased in polyandrous females. These results suggest that males may manipulate female immunity by interrupting the pro‐PO cascade, which begins with the activation of PO and ends in the encapsulation of invading foreign bodies. In other words, female immune function may serve as a battleground over which a sexual conflict is fought.
Asymmetrical reproductive character displacement in the house mouse
Authors: SMADJA C. , GANEM G. 
Published: August 2005

AbstractOur study addressed reproductive character displacement between two subspecies of the house mouse,Mus musculus musculusandMus musculus domesticusthat hybridize in Europe along a zone where selection against hybridization is known to occur. Based on a multi‐population approach, we investigated spatial patterns of divergence of mate preference in the two taxa. Mate preference was significantly higher in the contact zone than in allopatry in both subspecies, suggesting that reproductive character displacement occurs. Moreover, patterns of preference were stronger inM. m. musculusthan inM. m. domesticus, indicating an asymmetrical divergence between the two. In the context of selection against hybridization, our results may provide empirical support for the hypothesis of reinforcement in a parapatric hybrid zone. We discuss factors that could explain the asymmetrical pattern of divergence and the possible impact of a unimodal structure on the maintenance of premating divergence between the two subspecies.
Life‐history invariants with bounded variables cannot be distinguish from data generated by random processes using standard analyses
Authors: CIPRIANI R. , COLLIN R. 
Published: August 2005

AbstractA dimensionless approach to the study of life‐history evolution has been applied to a wide variety of variables in the search for life‐history invariants. This approach usually employs ordinary least squares (OLS) regressions of log‐transformed data. In several well‐studied combinations of variables the range of values of one parameter is bounded or limited by the value of the other. In this situation, the null hypothesis normally applied to regression analysis is not appropriate. We generate the null expectations and confidence intervals (CI) for OLS and reduced major axis (RMA) regressions using random variables that are bounded in this way. Comparisons of these CI show that, for log‐transformed data, the patterns generated by random data and those predicted by life history invariant theory often could not be distinguished because both predict a slope of 1. We recommend that tests based on the putative invariant ratios and not the correlations between the two variables be used in the exploration of life‐history invariants using bounded data. Because empirical data are often not normally distributed randomization test may be more appropriate than standard statistical tests.
Indirect consequences of artificial selection on plasticity to light quality inArabidopsis thaliana
Authors: CALLAHAN H. S. , PIGLIUCCI M. 
Published: August 2005

AbstractCovariation between light quality‐ and photoperiod‐mediated phenotypic plasticity was investigated usingArabidopsis thaliana.Three episodes of artificial selection were imposed on an index that quantified the plastic response to reduced red to far‐red ratios (R : FR), with higher index values indicating greater plasticity. Relative to control lines, two high plasticity (HP) lines showed 1.6‐ and 2.4‐fold increases in the index; low plasticity (LP) lines showed 1.4‐ and 1.1‐fold decreases. A factorial experiment combining high and low R : FR conditions with long and short photoperiods assessed indirect consequences of selection on plasticity. Despite divergent R : FR‐mediated plasticities in HP vs. LP lines, all four lines showed increases in photoperiod‐mediated responses and decreases in mean leaf number. Complex relationships among trait means, plasticities and underlying mechanisms caution against generalizing about the genetic architecture of plastic traits. Partially independent developmental and evolutionary responses to R : FR and photoperiod are somewhat unsurprising, given this species’ cosmopolitan nature.
The mode of evolution of aggregation pheromones in Drosophila species
Authors: SYMONDS M. R. E. , WERTHEIM B. 
Published: August 2005

AbstractAggregation pheromones are used by fruit flies of the genus Drosophila to assemble on breeding substrates, where they feed, mate and oviposit communally. These pheromones consist of species‐specific blends of chemicals. Here, using a phylogenetic framework, we examine how differences among species in these pheromone blends have evolved. Theoretical predictions, genetic evidence, and previous empirical analysis of bark beetle species, suggest that aggregation pheromones do not evolve gradually, but via major, saltational shifts in chemical composition. Using pheromone data for 28 species of Drosophila we show that, unlike with bark beetles, the distribution of chemical components among species is highly congruent with their phylogeny, with closely related species being more similar in their pheromone blends than are distantly related species. This pattern is also strong within the melanogaster species group, but less so within the virilis species group. Our analysis strongly suggests that the aggregation pheromones of Drosophila exhibit a gradual, not saltational, mode of evolution. We propose that these findings reflect the function of the pheromones in the ecology of Drosophila, which does not hinge on species specificity of aggregation pheromones as signals.
Life history evolution in cichlids 1: revisiting the evolution of life histories in relation to parental care
Authors: Kolm N. , Goodwin N. B. , Balshine S. , Reynolds J. D. 
Published: August 2005

Abstract
Empirical links between egg size and duration of parental care in fishes have generated a considerable amount of theory concerning life history evolution. However, to date, this link has not been investigated in relation to other important life-history traits such as clutch size and body size, or while controlling for shared ancestry between species. We provide the first phylogenetically based tests using a database with information on egg size, clutch size, body size and care duration in cichlid fishes (Cichlidae). Multiple regression analyses, based on independent contrasts on both the species and the genus level, showed that clutch size is the variable most closely related to duration of care. This pattern appeared to be driven by post-hatch care relationships. Our results show that, contrary to expectation, there is no positive link between egg size and care duration in Cichlidae. Instead, greater reproductive output through increased clutch size investment appears to have coevolved with greater care of offspring. We suggest that re-evaluation of the generality of current models of the evolution of egg size under parental care in fishes is needed.
Life history evolution in cichlids 2: directional evolution of the trade-off between egg number and egg size
Authors: Kolm N. , Goodwin N. B. , Balshine S. , Reynolds J. D. 
Published: August 2005

Abstract
The negative relationship between offspring number and offspring size provides a classic example of the role of trade-offs in life history theory. However, the evolutionary transitions in egg size and clutch size that have produced this negative relationship are still largely unknown. Since body size may affect both of these traits, it would be helpful to understand how evolutionary changes in body size may have facilitated or constrained shifts in clutch and egg size. By using comparative methods with a database of life histories and a phylogeny of 222 genera of cichlid fishes, we investigated the order of evolutionary transitions in these traits in relation to each other. We found that the ancestral large-bodied cichlids first increased egg size, followed by a decrease in both body size and clutch size resulting in the common current combination of a small-bodied cichlid with a small clutch of large eggs. Furthermore, lineages that deviated from the negative relationship between clutch and egg size underwent different transitions in these traits according to their body size (large bodied genera have moved towards the large clutch/small egg end of the continuum and small bodied genera towards the small clutch/large egg end of the continuum) to reach the negative relationship between clutch size and egg size. Our results show that body size is highly important in shaping the negative relationship between clutch size and egg size.
THE NATURAL HISTORY OF CERVICAL CARCINOMA IN SITU
Authors: Green G. H. , Donovan J. W. 
Published: August 2005

SummaryOf a total of 576 patients with cervical carcinoma in situ, 75 have shown evidence of persistent disease after various initial treatments. None of the 75 have developed invasive cervical cancer during follow‐up.This result is used to obtain confidence limits for the probability with which carcinoma in situ will become invasive and for the period after which it does so. Two separate assumptions about the distribution of latent periods give comparable values for these limits, which imply a low invasive potential in conservatively treated carcinoma in situ.With the further assumption that the treatments used have not altered the course of the disease, the need for any treatment at all and the effectiveness of cervical cytology screening programmes are questioned.
LOW SERUM B12 LEVELS AND LATENT ADDISONIAN ANAEMIA IN PREGNANCY
Authors: Hibbard Elizabeth D. , Spencer William J. 
Published: August 2005

SummaryInvestigation of B12 status during pregnancy in 518 women with anaemia or with a history of previous severe anaemia indicates that low serum B12 levels are not uncommon. In a number of cases with serum B12 levels below 50 pg. per ml., gastric parietal cell antibodies were detected. In two of these patients Schilling 57Co tests were positive. A diagnosis of latent Addisonian anaemia is made in these two women and the extent to which such a diagnosis must be considered in anaemic pregnant women is discussed.
TREATMENT OF PRIMARY AMENORRHOEA WITH HUMAN PITUITARY AND CHORIONIC GONADOTROPHINS
Authors: Gemzell C. , Carlborg L. , Johansson E. D. B. , Roos P. 
Published: August 2005

SummaryFifteen infertile women with primary amenorrhoea and pronounced oestrogen deficiency were treated with human pituitary gonadotrophin and human chorionic gonadotrophin 71 times; 61 ovulations (86 per cent) were recorded. Eleven patients conceived (73·5 per cent), three of them twice and one three times, giving 16 pregnancies in all. There were 12 single births and four sets of twins. Two pregnancies ended in abortion. On average one pregnancy resulted from 4·5 treatments and clinical symptoms of overstimulation occurred in 2 cycles (2·8 per cent).