bluuebunny/crossref_metadata_2025 huggingface dataset:
Hybridization and contemporary evolution in an introduced cichlid fish from Lake Malawi National Park
Authors: STREELMAN J. TODD , GMYREK S. L. , KIDD M. R. , KIDD C. , ROBINSON R. L. , HERT E. , AMBALI A. J. , KOCHER T. D.
Published: December 2004

Rapidly evolving systems offer the chance to observe genetic and phenotypic change in real time. We exploit a well‐characterized introduction of cichlid fish into Lake Malawi National Park to document a short history of habitat colonization and the evolution of genes and colour pattern. In the early 1960s, a fish exporter introduced individuals of Cynotilapia afra to a single site (Mitande Point) of Thumbi West Island and, as late as 1983, the species was confined to this location. In 2001, C. afra had colonized the entire perimeter of Thumbi West. In July of that year, we sampled C. afra individuals from six sites around the island and scored variation in dorsal fin colour as well as allelic diversity at six microsatellite loci. We found that, in two decades, C. afra had diverged into genetically distinct, phenotypically different northern and southern populations. We observed a high proportion of hybrids between the introduced C. afra and the native Metriaclima zebra on the southern coast of Thumbi West, and speculate that hybridization is facilitated by low water clarity at these windward sites. The short history of C. afra at Thumbi West is a microcosm of contemporary evolutionary divergence and may provide the opportunity to study the process from start to finish in genetic detail.
Admixture and diversity in West African cattle populations
Authors: FREEMAN A. R. , MEGHEN C. M. , MacHUGH D. E. , LOFTUS R. T. , ACHUKWI M. D. , BADO A. , SAUVEROCHE B. , BRADLEY D. G.
Published: December 2004

We present a population genetic analysis of microsatellite variation in 16 West African cattle populations. West Africa represents a unique juxtaposition of different climatic and ecological zones in a relatively small geographical area. While more humid coastal regions are inhabited by the tsetse fly, a vector which spreads trypanosomiasis among cattle, the disease is not transmitted in the drier areas outside this zone. This is the most thorough study of genetic diversity in cattle within this area, which contains genetically important trypanotolerant Bos taurus breeds. Genetic relationships among the many breeds are examined and levels of diversity are assessed. Admixture levels were determined using a variety of methods. Ancestry informative or population‐associated alleles (PAAs) were selected using populations from India, the Near East and Europe. Multivariate analysis, the admix program and model‐based Bayesian admixture analysis approaches were also employed. These analyses reveal the direct impact of ecological factors and the profound effect of admixture on the cattle of this region. They also highlight the importance of efforts to prevent further dilution of African taurine breeds by B. indicus cattle.
Genetic structuring of Patagonian toothfish populations in the Southwest Atlantic Ocean: the effect of the Antarctic Polar Front and deep‐water troughs as barriers to genetic exchange
Authors: SHAW P. W. , ARKHIPKIN A. I. , AL‐KHAIRULLA H.
Published: December 2004

The environmental and/or life history factors affecting genetic exchange in marine species with potential for high dispersal are of great interest, not only from an evolutionary standpoint but also with regard to effective management. Previous genetic studies have demonstrated substantial differentiation among populations of the Patagonian toothfish around the Southern Ocean, indicating breakdown of gene flow across large distances between inhabited shelf areas. The present study examined genetic structuring through analysis of microsatellite loci and restriction fragment length poymorphism (RFLP) of the mitochondrial ND2 gene and control region of the toothfish population in the SW Atlantic, allowing examination of the relative effects of the Antarctic Polar Front (APF), deep‐water troughs and distance between sites. Mitochondrial DNA (mtDNA) data indicated a sharp genetic division between the Patagonian Shelf/North Scotia Ridge and the Shag Rocks/South Georgia samples, whereas microsatellite data showed much less distinct structuring and an intermediate position of the North Scotia Ridge samples. We suggest these data indicate that the APF, as a barrier to larval dispersal, is the major inhibitor of genetic exchange between toothfish populations, with deep‐water troughs and distance between sites contributing to genetic differentiation by inhibiting migration of relatively sedentary adults. We also suggest that differences between mtDNA and nuclear DNA population patterns may reflect either genome population size effects or (putative) male‐biased dispersal.
Nonallopatric and parallel origin of local reproductive barriers between two snail ecotypes
Authors: ROLÁN‐ALVAREZ EMILIO , CARBALLO MONICA , GALINDO JUAN , MORÁN PALOMA , FERNÁNDEZ BLANCA , CABALLERO ARMANDO , CRUZ RAQUEL , BOULDING ELIZABETH G. , JOHANNESSON KERSTIN
Published: December 2004

Theory suggests that speciation is possible without physical isolation of populations (hereafter, nonallopatric speciation), but recent nonallopatric models need the support of irrefutable empirical examples. We collected snails (Littorina saxatilis) from three areas on the NW coast of Spain to investigate the population genetic structure of two ecotypes. Earlier studies suggest that these ecotypes may represent incipient species: a large, thick‐shelled ‘RB’ ecotype living among the barnacles in the upper intertidal zone and a small, thin‐shelled ‘SU’ ecotype living among the mussels in the lower intertidal zone only 10–30 m away. The two ecotypes overlap and hybridize in a midshore zone only 1–3 m wide. Three different types of molecular markers [allozymes, mitochondrial DNA (mtDNA) and microsatellites] consistently indicated partial reproductive isolation between the RB and the SU ecotypes at a particular site. However, each ecotype was related more closely to the other ecotype from the same site than to the same ecotype from another site further along the Galician coast (25–77 km away). These findings supported earlier results based solely on allozyme variation and we could now reject the possibility that selection produced these patterns. The patterns of genetic variation supported a nonallopatric model in which the ecotypes are formed independently at each site by parallel evolution and where the reproductive barriers are a byproduct of divergent selection for body size. We argue that neither our laboratory hybridization experiments nor our molecular data are compatible with a model based on allopatric ecotype formation, secondary overlap and introgression.
Molecular evidence for Pleistocene glacial cycles driving diversification of a North American desert spider, Agelenopsis aperta
Authors: AYOUB NADIA A. , RIECHERT SUSAN E.
Published: December 2004

The influence of historical climatic vs. geological changes on species diversification patterns was investigated in a widely distributed North American desert spider, Agelenopsis aperta (Araneae: Agelenidae), with particular reference to Pleistocene glacial cycles and earlier patterns of mountain building. Levels of sequence divergence obtained from the mitochondrial gene, cytochrome oxidase I, dated to the Pleistocene, eliminating Rocky Mountain orogeny as a cause of diversification, as orogeny ended 4 million years ago. The results of phylogenetic and network analyses showed the presence of three geographically defined clades, which were consistent with the presence of at least three glacial refugia: (i) east of the Rocky Mountains; (ii) between the Rocky Mountains and Sierra Nevadas; and (iii) west of the Sierra Nevadas. In addition, populations within the Rocky Mountains exhibited significantly lower genetic diversity than populations east of the Rocky Mountains and the haplotypes found within the Rockies were a subset of eastern haplotypes. These patterns suggest that a post‐Pleistocene range expansion occurred out of an eastern glacial refugium into the Rocky Mountains. Examination of phylogeographical studies of other North American desert taxa indicated that mountain building explained diversification patterns more effectively for some taxa but Pleistocene climate change was more important for others, including A. aperta.
Reconciling geography and genealogy: phylogeography of giant freshwater prawns from the Lake Carpentaria region
Authors: DE BRUYN MARK , WILSON JOHN C. , MATHER PETER B.
Published: December 2004

There is convincing geological evidence for the historical existence of an ancient lake on the Australian–New Guinea continental shelf during the late Pleistocene. Lake Carpentaria was a vast fresh‐ to brackishwater lake that would presumably have provided habitat for, and facilitated gene flow among, aquatic taxa that tolerate low to moderate salinities in this region. Moreover, it has been argued that the outflow of Papua New Guinea's Fly River was diverted westward into Lake Carpentaria during this period, although this hypothesis is controversial. We predicted that these events, if a true history, would have promoted gene flow and population growth via range‐expansion events in the giant freshwater prawn (Macrobrachium rosenbergii) and restricted gene flow subsequently by way of a vicariant event as sea levels rose during the late Pleistocene, and a marine environment replaced Lake Carpentaria. We tested these hypotheses using phylogeographical and phylogenetic analyses of mitochondrial DNA variation in M. rosenbergii populations sampled from the Lake Carpentaria region. Our results support the hypothesis that Lake Carpentaria facilitated gene flow among populations of M. rosenbergii that are today isolated, but contest claims of a westward diversion of the Fly River. We inferred the timing of initial expansion in the ‘Lake Carpentaria lineage’ and found the timing of this event to be broadly concordant with geological dating of the formation of Lake Carpentaria. Reconciling geological and molecular data, as presented here, provides a powerful framework for investigating the influence of historical earth history events on the distribution of biological (i.e. molecular) diversity.
Mitochondrial DNA variation and population structure of the island endemic Azorean bat (Nyctalus azoreum)
Authors: SALGUEIRO P. , COELHO M. M. , PALMEIRIM J. M. , RUEDI M.
Published: December 2004

The Azorean batNyctalus azoreumis the only endemic mammal native to the remote archipelago of the Azores. It evolved from a continental ancestor related to the Leisler's batNyctalus leisleriand is considered threatened because of its restricted and highly fragmented distribution. We studied the genetic variability in 159 individuals from 14 colonies sampled throughout the archipelago. Sequences of the D‐loop region revealed moderate but highly structured genetic variability. Half of the 15 distinct haplotypes were restricted to a single island, but the most common was found throughout the archipelago, suggesting a single colonization event followed by limited interisland female gene flow. AllN. azoreumhaplotypes were closely related and formed a star‐like structure typical of expanded populations. The inferred age of demographic expansions was consistent with the arrival of founder animals during the Holocene, well before the first humans inhabited the Azores. Comparisons with a population ofN. leislerifrom continental Portugal confirmed not only that allN. azoreumlineages were unique to the archipelago, but also that the current levels of genetic diversity were surprisingly high for an insular species. Our data imply that the Azorean bat has a high conservation value. We argue that geographical patterns of genetic structuring indicate the existence of two management units.
Identification of a PEST‐like motif in listeriolysin O required for phagosomal escape and for virulence in Listeria monocytogenes
Authors: Lety Marie‐Annick , Frehel Claude , Dubail Iharilalao , Beretti Jean‐Luc , Kayal Samer , Berche Patrick , Charbit Alain
Published: December 2004

The hly‐encoded listeriolysin O (LLO) is a major virulence factor secreted by the intracellular pathogen Listeria monocytogenes, which plays a crucial role in the escape of bacteria from the phagosomal compartment. Here, we identify a putative PEST sequence close to the N‐terminus of LLO and focus on the role of this motif in the biological activities of LLO. Two LLO variants were constructed: a deletion mutant protein, lacking the 19 residues comprising this sequence (residues 32–50), and a recombinant protein of wild‐type size, in which all the P, E, S or T residues within this motif have been substituted. The two mutant proteins were fully haemolytic and were secreted in culture supernatants of L. monocytogenes in quantities comparable with that of the wild‐type protein. Strikingly, both mutants failed to restore virulence to a hly‐negative strain in vivo. In vitro assays showed that L. monocytogenes expressing the LLO deletion mutant was strongly impaired in its ability to escape from the phagosomal vacuole and, subsequently, to divide in the cytosol of infected cells. This work reveals for the first time that the N‐terminal portion of LLO plays an important role in the development of the infectious process of L. monocytogenes.
Generation and characterization of a PhoP homologue mutant of Neisseria meningitidis
Authors: Johnson C. R. , Newcombe J. , Thorne S. , Borde H. A. , Eales‐Reynolds L.‐J. , Gorringe A. R. , Funnell S. G. P. , McFadden J. J.
Published: December 2004

Two‐component regulatory systems are important regulators of virulence genes in a number of bacteria. Genes encoding a two‐component regulator system, with homology to the phoP/phoQ system in salmonella, were identified in the meningococcal genome. Allele replacement was used to generate a meningococcal knock‐out mutant of the regulator component of this system, and its phenotype was examined. The mutant displayed many differences in protein profiles compared with wild type, consistent with it being a gene‐regulatory mutation. Many of the growth characteristics of the mutant were similar to those of phoP mutants of salmonella: it was unable to grow at low concentrations of magnesium and was sensitive to defensins and other environmental stresses. Magnesium‐regulated differences in protein expression were abrogated in the mutant, indicating that the meningococcal PhoP/PhoQ system may, as in salmonella, respond to changes in environmental magnesium levels. These results are consistent with the PhoP homologue playing a similar role in the meningococcus to PhoP in salmonella and suggest that it may similarly be involved in the regulation of virulence genes in response to environmental stimuli in the meningococcus. In support of this conclusion, we found the mutant grew was unable to grow in mouse serum and was attenuated in its ability to traverse through a layer of human epithelial cells. Identification of those genes regulated by the meningococcal PhoP may provide a route towards the identification of virulence genes in the meningococcus.
Genome plasticity in Streptomyces: identification of 1 Mb TIRs in the S. coelicolor A3(2) chromosome
Authors: Weaver David , Karoonuthaisiri Nitsara , Tsai Hsiu‐Hwei , Huang Chih‐Hung , Ho Mai‐Lan , Gai Shuning , Patel Kedar G. , Huang Jianqiang , Cohen Stanley N. , Hopwood David A. , Chen Carton W. , Kao Camilla M.
Published: December 2004

The chromosomes of several widely used laboratory derivatives of Streptomyces coelicolor A3(2) were found to have 1.06 Mb inverted repeat sequences at their termini (i.e. long‐terminal inverted repeats; L‐TIRs), which are 50 times the length of the 22 kb TIRs of the sequenced S. coelicolor strain M145. The L‐TIRs include 1005 annotated genes and increase the overall chromosome size to 9.7 Mb. The 1.06 Mb L‐TIRs are the longest reported thus far for an actinomycete, and are proposed to represent the chromosomal state of the original soil isolate of S. coelicolor A3(2). S. coelicolor A3(2), M600 and J1501 possess L‐TIRs, whereas approximately half the examined early mutants of A3(2) generated by ultraviolet (UV) or X‐ray mutagenesis have truncated their TIRs to the 22 kb length. UV radiation was found to stimulate L‐TIR truncation. Two copies of a transposase gene (SCO0020) flank 1.04 Mb of DNA in the right L‐TIR, and recombination between them appears to generate strains containing short TIRs. This TIR reduction mechanism may represent a general strategy by which transposable elements can modulate the structure of chromosome ends. The presence of L‐TIRs in certain S. coelicolor strains represents a major chromosomal alteration in strains previously thought to be genetically similar.
Transcription activation at the Escherichia coli melAB promoter: interactions of MelR with the C‐terminal domain of the RNA polymerase α subunit
Authors: Grainger David C. , Belyaeva Tamara A. , Lee David J. , Hyde Eva I. , Busby Stephen J. W.
Published: December 2004

We have investigated the role of the RNA polymerase α subunit during MelR‐dependent activation of transcription at the Escherichia coli melAB promoter. To do this, we used a simplified melAB promoter derivative that is dependent on MelR binding at two 18 bp sites, located from position −34 to −51 and from position −54 to −71, upstream of the transcription start site. Results from experiments with hydroxyl radical footprinting, and with RNA polymerase, carrying α subunits that were tagged with a chemical nuclease, show that the C‐terminal domains of the RNA polymerase α subunits are located near position −52 and near position −72 during transcription activation. We demonstrate that the C‐terminal domain of the RNA polymerase α subunit is needed for open complex formation, and we describe two experiments showing that the RNA polymerase α subunit can interact with MelR. Finally, we used alanine scanning to identify determinants in the C‐terminal domain of the RNA polymerase α subunit that are important for MelR‐dependent activation of the melAB promoter.
Regulation and differential expression of gdhA encoding NADP‐specific glutamate dehydrogenase in Neisseria meningitidis clinical isolates
Authors: Pagliarulo Caterina , Salvatore Paola , De Vitis Lucia Rosaria , Colicchio Roberta , Monaco Caterina , Tredici Maurizio , Talà Adelfia , Bardaro Marcellino , Lavitola Alfredo , Bruni Carmelo B. , Alifano Pietro
Published: December 2004

Meningococcal gdhA, encoding the NADP‐specific l‐glutamate dehydrogenase (NADP‐GDH), is essential for systemic infection in an infant rat model. In this paper, a limited transcriptional analysis detected differences in gdhA expression among clinical isolates. In strains expressing high levels of gdhA mRNA, two promoters, gdhA P1 and gdhA P2, initiated transcription of gdhA. In contrast, in strains expressing low mRNA levels, gdhA P2 was not active because of weak expression of gdhR, an associated regulatory gene. Gene knock‐out and complementation of a gdhR‐defective mutant confirmed that GdhR is a positive regulator for gdhA P2. Trans‐activation of gdhA P2 was maximal in complex medium during late logarithmic growth phase and in chemical defined medium (MCDA) when glucose (MCDA‐glucose) instead of lactate (MCDA‐lactate) was used as a carbon source in the presence of glutamate. gdhR knock‐out mutants lost both growth phase and carbon source regulation, and exhibited a growth defect more severe in MCDA‐glucose than in MCDA‐lactate. DNA–protein interaction studies demonstrated that 2‐oxoglutarate, a product of the catabolic reaction of the NADP‐GDH and an intermediate of the tricarboxylic acid (TCA) cycle, inhibits binding of GdhR to gdhA P2.
The Sup35 domains required for maintenance of weak, strong or undifferentiated yeast [PSI+] prions
Authors: Bradley Michael E. , Liebman Susan W.
Published: December 2004

The Sup35 protein can exist in a non‐infectious form or in various infectious forms called [PSI+] prion variants (or prion strains). Each of the different [PSI+] prion variants converts non‐infectious Sup35 molecules into that prion variant's infectious form. One definition of a ‘prion domain’ is the minimal fragment of a prion protein that is necessary and sufficient to maintain the prion form. We now demonstrate that the Sup35 N region (residues 1–123), which is frequently referred to as the ‘prion domain’, is insufficient to maintain the weak or strong [PSI +] variants per se, but appears to maintain them in an ‘undifferentiated’[PSI+] state that can differentiate into weak or strong [PSI+] variants when transferred to the full‐length Sup35 protein. In contrast, Sup35 residues 1–137 are necessary and sufficient to faithfully maintain weak or strong [PSI+] variants. This implicates Sup35 residues 124–137 in the variant‐specific maintenance of the weak or strong [PSI+] forms. Structure predictions indicate that the residues in the 124–137 region form an α‐helix and that the 1–123 region may have β structure. In view of these findings, we discuss a plausible molecular basis for the [PSI+] prion variants as well as the inherent difficulties in defining a ‘prion domain’.
Involvement of two domains with helix–turn–helix and zinc finger motifs in the binding of IS1 transposase to terminal inverted repeats
Authors: Ohta Shinya , Yoshimura Etsuro , Ohtsubo Eiichi
Published: December 2004

The insertion element IS1 has two open reading frames (ORFs), insA and insB, and produces a transframe protein InsAB, known as IS1 transposase, by translational frameshifting. The transposase binds to terminal inverted repeats (IRL and IRR) to promote IS1 transposition. Unless frameshifting occurs, IS1 produces InsA protein, which also binds to IRs and therefore acts as an inhibitor of transposition, as well as a transcriptional repressor of the promoter in IRL. A helix–turn–helix (HTH) motif present in both transposase and InsA is thought to be involved in IR‐specific DNA binding. A comparison of transposases encoded by IS1 family elements reveals that the N‐terminal regions contain four conserved cysteine residues, which appear to constitute a C2C2 zinc finger (ZF) motif. This motif is also thought to be involved in IR‐specific DNA binding. In this study, we show that IS1 transposases with an amino acid substitution in the HTH or ZF motif lose the ability to promote transposition. We also show that transposases, as well as InsA proteins with the same substitution, lose the ability to repress the activity of the IRL promoter, and that purified InsA mutant proteins lose the ability to bind to the IRL‐containing fragment. Furthermore, we show that InsA protein co‐ordinates Zn(II) with the four cysteine residues as ligands and loses the ability to bind to the IRL‐containing fragment in the presence of an agent chelating Zn(II). These findings indicate that IS1 transposase has two domains with HTH and ZF motifs responsible for IR‐specific DNA binding in promoting transposition. It is assumed that the two domains are needed for transposase to bind to each IR in an oriented manner in order to place a catalytic domain in the C‐terminal region of the transposase to a region around the IR end, where the strand transfer reaction occurs in a transpososome.
The role of Par proteins in the active segregation of the P1 plasmid
Authors: Li Yongfang , Dabrazhynetskaya Alena , Youngren Brenda , Austin Stuart
Published: December 2004

The parS centromere‐like site promotes active P1 plasmid segregation in the presence of P1 ParA and ParB proteins. At the modest growth rate used here, time‐lapse and still photomicroscopy shows that the plasmid copies are clustered as a focus at the Escherichia coli cell centre. Just before cell division, the focus is actively divided and ejects bidirectionally into opposite halves of the dividing cell. In the absence of the wild‐type parS binding protein ParB, a focus was formed, but generally did not go to the cell centre. The randomly placed focus did not divide and was inherited by one daughter cell only. In the absence of ParA, foci formed and frequently fixed to the cell centre. However, they failed to divide or eject and were left at the new cell pole of one cell at division. Thus, ParB appears to be required for recognition of the plasmid and its attachment to the cell centre, and ParA is required for focus division and energetic ejection from the cell centre. The ATPase active site mutation, parAK122E, blocked ejection. Mutant parAM314I ejected weakly, and the daughter foci took two generations to reach a new cell centre. This explains the novel alternation of segregation and missegregation in successive generations seen in time‐lapse images of this mutant.
Histomorphometry of brain tumours
Authors: Nafe R. , Schlote W.
Published: December 2004

In this review, the results of previous histomorphometric studies of brain tumours are summarized and discussed with respect to their potential value for diagnostic purposes and for tumour research. In the majority of these studies, human gliomas were investigated. In a few studies, human meningiomas and other human or experimental tumour types were investigated. A computerized image analysis system was used for the morphometric analyses in most studies. The three main histologic structures examined were tumour cell nuclei, nucleolar organizer regions and tumour vessels. The current state of knowledge provides evidence that a diagnostic benefit could be provided by histomorphometric investigations of brain tumours, especially for grading of gliomas and with respect to independent prognostic information. Additional studies are necessary to delineate the spectrum of histomorphometric parameters and the investigation of their prognostic significance for cases with the same tumour type and tumour grade. Together with many recently published observations in this field, this review shows that histomorphometry is an important approach towards the investigation of brain tumour biology.
The accumulation of deleterious mutations within the frozen niche variation hypothesis
Authors: Pound G. E. , Cox S. J. , Doncaster C. P.
Published: December 2004

The frozen niche variation hypothesis proposes that asexual clones exploit a fraction of a total resource niche available to the sexual population from which they arise. Differences in niche breadth may allow a period of coexistence between a sexual population and the faster reproducing asexual clones. Here, we model the longer term threat to the persistence of the sexual population from an accumulation of clonal diversity, balanced by the cost to the asexual population resulting from a faster rate of accumulation of deleterious mutations. We use Monte-Carlo simulations to quantify the interaction of niche breadth with accumulating deleterious mutations. These two mechanisms may act synergistically to prevent the extinction of the sexual population, given: (1) sufficient genetic variation, and consequently niche breadth, in the sexual population; (2) a relatively slow rate of accumulation of genetic diversity in the clonal population; (3) synergistic epistasis in the accumulation of deleterious mutations.
Sexual selection on morphological and physiological traits and fluctuating asymmetry in the black scavenger fly Sepsis cynipsea
Authors: Blanckenhorn W. U. , Kraushaar U. R. S. , Teuschl Y. , Reim C.
Published: December 2004

Previous univariate studies of the fly Sepsis cynipsea (Diptera: Sepsidae) have demonstrated spatiotemporally variable and consequently overall weak sexual selection favouring large male size, which is nevertheless stronger on average than fecundity selection favouring larger females. To identify specific target(s) of selection on body size and additional traits possibly affecting mating success, two multivariate field studies of sexual selection were conducted. In one study using seasonal replicates from three populations, we assessed 15 morphological traits. No clear targets of sexual selection on male size could be detected, perhaps because spatiotemporal variation in selection was again strong. In particular, there was no (current) selection on male abdomen length or fore coxa length, the only traits for which S. cynipsea males are not smaller than females. Interestingly, copulating males had a consistently shorter fore femur base, a secondary sexual trait, and a wider clasper (hypopygium) gap, an external genital trait. In a second study using daily and seasonal replicates from one population, we included physiological measures of energy reserves (lipids, glucose, glycogen), in addition to hind tibia length and fluctuating asymmetry (FA) of all pairs of legs. This study again confirmed the mating advantage of large males, and additionally suggests independent positive influences of lipids (the long-term energy stores), with effects of glucose and glycogen (the short-term energy stores) tending to be negative. FA of paired traits was not associated with male mating success. Our study suggests that inclusion of physiological measures and genital traits in phenomenological studies of selection, which is rare, would be fruitful in other species.
The role of complement in invasive fungal infections
Authors: Speth Cornelia , Rambach Günter , Lass‐Flörl Cornelia , Dierich Manfred P. , Würzner Reinhard
Published: December 2004

New therapeutic approaches enable organ transplantations and guarantee longer survival for AIDS patients or patients with haematological neoplasia. The price for these medical advances is immunosuppression and thus enhanced susceptibility to opportunistic fungal infections. As a consequence invasive fungal infections are on the march in modern medicine. Therapeutic limitations and difficulties strongly demand for a deeper understanding of the interaction between the various fungi and the hosts’ innate and adaptive immune defence system. This understanding is the essential prerequisite for a potential therapeutic approach, which may support specifically the insufficient antifungal attack of the host. In the present article, we therefore review the current knowledge of the role of the complement system as a central part of innate immunity and as a fine tuner of adaptive immunity in the pathogenesis of invasive fungal infections, such as aspergillosis, candidosis, cryptococcosis, paracoccidioidomycosis, blastomycosis and histoplasmosis.
Outpatients undergoing therapeutic endoscopic retrograde cholangiopancreatography: Six‐hour versus overnight observation
Authors: HUI CHEE‐KIN , LAI KAM‐CHUEN , WONG WAI‐MAN , YUEN MAN‐FUNG , NG MATTHEW , CHAN CHI‐KUEN , HU WAYNE , CHEUNG WINNIE W , LAI CHING‐LUNG , WONG BENJAMIN CY
Published: December 2004

Background and Aim:  The purpose of the present retrospective study was to compare the proportion of post‐endoscopic retrograde cholangiopancreatography (ERCP) complications detected with 6‐h observation followed by same‐day discharge (SDD) versus overnight observation (OO) after therapeutic ERCP.

Methods:  There were 134 outpatients in the SDD group and 178 outpatients in the OO group. The SDD group was discharged after a 6‐h observation while the OO group was discharged after overnight observation. Patients in the SDD group were admitted from the recovery room for evaluation if they had systolic blood pressure (BP) < 100 mmHg, pulse > 100/min, temperature > 37.5°C, or post‐procedure abdominal pain. The primary outcome of the present study was the proportion of post‐ERCP complications detected within the observational period between the SDD group and the OO group.

Results:  The post‐ERCP complication rate of therapeutic ERCP in the SDD and OO groups were 9.7% and 9.6%, respectively (P = 0.964). Eleven patients (8.2%) in the SDD group and 13 patients (7.3%) in the OO group were found to have post‐ERCP complications within the observation period. There was no significant difference in the proportion of post‐ERCP complications detected within the observational period between the two groups (P = 0.672).

Conclusion:  Outpatient therapeutic ERCP with observation of 6 h can detect the same proportion of patients with post‐ERCP complications as overnight observation.

© 2004 Blackwell Publishing Asia Pty Ltd
The Stationary Marginal Distribution of a Threshold AR(1) Process
Authors: LOGES WILFRIED
Published: December 2004

An explicit analytic solution for the stationary marginal distribution of a simple threshold autoregressive process is given. Furthermore, closed form expressions for all moments of the process are presented. The derivation is based on the use of the Frobenius–Perron operator.
The influence of children on parental purchases during supermarket shopping
Authors: Wilson George , Wood Katie
Published: December 2004

Children are assuming larger roles in household consumer decisions and have also emerged as independent consumers, thus forming an increasingly powerful market segment. Children can be seen as forming, first, a primary market; second, as influencers on their parents’ decision making; and third, as potential future adult consumers. The second role is the main focus of this paper, centring on supermarket purchases. Using focus groups and in‐depth interviews, this study explores the influence of children on supermarket shopping. Participants included parents and children of families in Midlothian, Scotland. The results showed that children have a significant influence on supermarket product purchases. The factors which influence children's product preferences are analysed, and their ability to relay their choices to their parents is considered.
Electronic shopping: young people as consumers
Authors: Ige Olalonpe
Published: December 2004

Findings and discussions in this paper lead to recommendations in relation to young people as consumers in the electronic marketplace. The recommendations in this paper may be of value to students, academics, e‐marketers and e‐retailers. This paper seeks to take a cross‐border perspective while discussing the issue of young consumers and electronic shopping. It attempts to discuss significant macro‐environmental influences on young consumers in the electronic commerce market. It also highlights important opportunities and threats, relevant to the young consumers target market. The paper finally introduces generic strategies that may be used to successfully target the youth market and discusses resulting implications. Before delving into the electronic shopping market analysis and the strategic focus on young people, the paper will first introduce the meaning of electronic shopping and highlight the interdependent nature of electronic shopping and e‐commerce. It will also explain what is meant by young consumers in the context of this study.
Enhancing the MeSH thesaurus to retrieve French online health resources in a quality‐controlled gateway
Authors: Douyère Magaly , Soualmia Lina F. , Névéol Aurélie , Rogozan Alexandrina , Dahamna Badisse , Leroy Jean‐Philippe , Thirion Benoît , Darmoni Stefan J.
Published: December 2004

The amount of health information available on the Internet is considerable. In this context, several health gateways have been developed. Among them, CISMeF (Catalogue and Index of Health Resources in French) was designed to catalogue and index health resources in French. The goal of this article is to describe the various enhancements to the MeSH thesaurus developed by the CISMeF team to adapt this terminology to the broader field of health Internet resources instead of scientific articles for the medline bibliographic database. CISMeF uses two standard tools for organizing information: the MeSH thesaurus and several metadata element sets, in particular the Dublin Core metadata format. The heterogeneity of Internet health resources led the CISMeF team to enhance the MeSH thesaurus with the introduction of two new concepts, respectively, resource types and metaterms. CISMeF resource types are a generalization of the publication types of medline. A resource type describes the nature of the resource and MeSH keyword/qualifier pairs describe the subject of the resource. A metaterm is generally a medical specialty or a biological science, which has semantic links with one or more MeSH keywords, qualifiers and resource types. The CISMeF terminology is exploited for several tasks: resource indexing performed manually, resource categorization performed automatically, visualization and navigation through the concept hierarchies and information retrieval using the Doc’CISMeF search engine. The CISMeF health gateway uses several MeSH thesaurus enhancements to optimize information retrieval, hierarchy navigation and automatic indexing.
Developing methods for systematic reviewing in health services delivery and organization: an example from a review of access to health care for people with learning disabilities. Part 2. Evaluation of the literature—a practical guide
Authors: Alborz Alison , McNally Rosalind
Published: December 2004

Objectives:  To develop methods to facilitate the ‘systematic’ review of evidence from a range of methodologies on diffuse or ‘soft’ topics, as exemplified by ‘access to health care’.

Data sources:  Twenty‐eight bibliographic databases, research registers, organizational websites or library catalogues. Reference lists from identified studies. Contact with experts and service users. Current awareness and contents alerting services in the area of learning disabilities.

Review methods:  Inclusion criteria were English language literature from 1980 onwards, relating to people with learning disabilities of any age and all study designs. The main criteria for assessment was relevance to Guillifords’ model of access to health care which was adapted to the circumstances of people with learning disabilities. Selected studies were evaluated for scientific rigour then data was extracted and the results synthesized. Quality assessment was by an initial set of ‘generic’ quality indicators. This enabled further evidence selection before evaluation of findings according to specific criteria for qualitative, quantitative or mixed‐method studies.

Results:  Eighty‐two studies were fully evaluated. Five studies were rated ‘highly rigorous’, 22 ‘rigorous’, 46 ‘less rigorous’ and nine ‘poor’ papers were retained as the sole evidence covering aspects of the guiding model. The majority of studies were quantitative but used only descriptive statistics. Most evidence lacked methodological detail, which often lowered final quality ratings.

Conclusions:  The application of a consistent structure to quality evaluation can facilitate data appraisal, extraction and synthesis across a range of methodologies in diffuse or ‘soft’ topics. Synthesis can be facilitated further by using software, such as the microsoft ‘access’ database, for managing information.
Species poor but distinct: bird assemblages in white sand vegetation in Jaú National Park, Brazilian Amazon
Authors: Borges Sérgio Henrique
Published: December 2004

There have been few studies of the fauna of the distinctive vegetation that grows on sandy soil in Amazonia. Leached and nutrient‐poor sandy soil is associated with a vegetation type that varies in structure from open fields (campinas) to low canopy forests (campinaranas). During a bird inventory in sandy soil vegetation at Jaú National Park (JNP), I recorded 128 bird species, with 55 in campina and 94 in campinarana. Estimates suggested only 150 bird species should be expected to occur in these habitats, a reduced species diversity compared with other vegetation types in the Amazon region. This low species diversity is probably linked to the low productivity of this habitat and its relatively simple vegetation structure. Despite the relatively low diversity, at least 14 bird species (3% of the entire avifauna) appear to be restricted to white sand vegetation in JNP. In Amazonia as a whole, some 37 bird species are associated with vegetation in sandy soils. Biological inventories of other taxa are needed to understand the contribution of white sandy vegetation to the faunal distribution in Amazonia.
Life‐history of two African Sylvia warblers: low annual fecundity and long post‐fledging care
Authors: Schaefer Hans‐Christian , Eshiamwata George W. , Munyekenye Fred B. , Böhning‐Gaese Katrin
Published: December 2004

The investigation of factors that cause differences in life‐history traits between temperate and tropical birds is often hampered by a lack of knowledge about tropical species. Even within the well‐known warblers of the genus Sylvia, which include resident species from temperate and tropical regions as well as migrants, there are few data from tropical species. We investigated the breeding biology of the tropical species Sylvia lugens and S. boehmi in a 2‐year study in Kenya. Both species had a clutch size of 2.0 and laid c. 3.7 clutches per year. Breeding was characterized by long incubation periods (S. lugens 14.5 days, S. boehmi 15.0 days), long nestling periods (16.0 and 12.9 days, respectively) and high predation rates (Mayfield nest success S. lugens 33.2%, S. boehmi 19.4%). Annual fecundity was 2.3 fledglings in S. lugens and 1.4 fledglings in S. boehmi. After fledging, the young birds were fed for 37.5 days (S. lugens) and 58.5 days (S. boehmi) (time to independence) and they stayed in their parents’ territory for days or weeks, even after feeding had stopped. Fledgling survival until independence was 55.4% in S. lugens and 69.2% in S. boehmi. In general, S. lugens and S. boehmi have smaller but more numerous clutches, longer developmental periods, higher nest predation rates, lower annual fecundity and longer post‐fledging care than their temperate congenerics.
A mathematical model of factors that influence the performance of accommodative intraocular lenses
Authors: Heatley C. J. , Spalton D. J. , Boyce J. F. , Marshall J.
Published: December 2004

In this work a mathematical model of capsule movement during pseudophakic accommodation is described to allow identification and evaluation of factors that may explain the variation in effect of accommodative intraocular lenses (IOLs) between patients. The model assumes that increasing vitreous pressure pushes the lens capsule forward as a circular diaphragm and that this movement is from a fixed fulcrum. With an IOL in situ, the capsule is taken to have a non‐uniform thickness due to the presence of the anterior capsulorhexis. The model assumes a uniform capsular elasticity and ignores contributions from cellular elements such as posterior capsule opacification. Using our model and a regression formula to calculate capsular bag size, taking into account axial length and keratometry values, we are able to predict accommodative effect in individual patients. By simple geometry we have developed a mathematical model to identify variables that are important in pseudophakic accommodation. It provides the basis for the development of a more complex model that would address the movement of a lens taking into account the influence of the zonular system during accommodation.
Subjective Memory Complaints and Objective Memory Impairment in the Vienna‐Transdanube Aging Community
Authors: Jungwirth Susanne , Fischer Peter , Weissgram Silvia , Kirchmeyr Walter , Bauer Peter , Tragl Karl‐Heinz
Published: December 2004

Objectives: To help answer the question of whether subjective memory complaints are a useful feature in classification systems addressing early stages of Alzheimer's disease.

Design: A cross‐sectional investigation in the context of a community‐based cohort study.

Setting: Vienna, Transdanube—a geographically defined, urban, working‐class area.

Participants: Three hundred two nondemented 75‐year‐olds were examined with regard to subjective memory complaints and objective memory performance. The patients were divided into two groups with respect to subjective memory complaints and into two groups with respect to memory performance on the Fuld Object Memory Evaluation.

Measurements: The percentage of individuals with memory complaints who also had objective memory impairment and the percentage of individuals with objective memory impairment who also complained about their memory were measured.

Results: One‐tenth (10.6%) (95% confidence interval (CI)=7.7–14.7) of community based sample of 75‐year‐old subjects complained about their memory. There was no difference between complainers and noncomplainers with regard to actual memory performance. Only 6.3% (95% CI=0.16–30.2) of memory‐impaired subjects complained about their proven memory impairment.

Conclusion: About 94% (95% CI=69.8–99.8) of memory‐impaired individuals do not complain about memory problems. Subjective memory complaints may not be a useful feature in current diagnostic criteria of mild cognitive impairment.
Taking the Next Steps in Goal Ascertainment: A Prospective Study of Patient, Team, and Family Perspectives Using a Comprehensive Standardized Menu in a Geriatric Assessment and Treatment Unit
Authors: Glazier Sherry R. , Schuman John , Keltz Esther , Vally Ashnor , Glazier Richard H.
Published: December 2004

Objectives: To examine the performance of an expanded menu of goals in a geriatric rehabilitation setting incorporating patient, family, and team perspectives.

Design: Prospective comparative study.

Setting: Inpatient geriatric rehabilitation unit.

Participants: Nineteen consecutive eligible inpatients and their family members and seven unit team members.

Measurements: Each participant independently reviewed a standardized menu of medical, functional, psychosocial, spiritual, and future planning goals, which were compared with the goals set by the healthcare team.

Results: On average, patients and their family members agreed on goals about half the time; family members tended to have more goals than patients. Agreement between the team and patients and families was poor (kappas=−0.11–0.33). The team was less likely to identify functional, psychosocial, spiritual, and future planning goals.

Conclusion: Patients and families have a broad range of goals that are not always identified by the healthcare team. A comprehensive standardized menu is feasible and may be helpful in setting goals in a geriatric rehabilitation setting.
Ethics Reporting in Publications About Research with Alzheimer's Disease Patients
Authors: Stocking Carol B. , Hougham Gavin W. , Baron Aliza R. , Sachs Greg A.
Published: December 2004

Persons with impaired decision‐making capacity require special ethical protections during recruitment for and participation in research. To assess how fully basic protections for these persons were reported in the literature, the first structured review of a sample of reports of trials including Alzheimer's subjects was performed in 62 journals between January 1992 and December 1998. Neither institutional review board review nor informed consent was mentioned in 28% of the studies. In 48% of the studies, there was no mention of subject involvement in the consent process or that any potential subjects refused or withdrew. Protections may have been offered and simply not reported in the journal articles. The critical importance of these protections would be demonstrated if editors required that authors provide full documentation of ethical protections when submitting an article for review. These might be briefly reported in the articles but be made available electronically to interested readers. Authors could then specify in detail how they conducted their research involving persons with diminished decision‐making capacity.