bluuebunny/crossref_metadata_2025_split huggingface dataset:
Genetic variation and evolution of Polaskia chichipe (Cactaceae) under domestication in the Tehuacán Valley, central Mexico
Authors: OTERO‐ARNAIZ ADRIANA , CASAS ALEJANDRO , HAMRICK JAMES L. , CRUSE‐SANDERS JENNIFER 
Published: April 2005

Abstract Polaskia chichipe is a columnar cactus under artificial selection in central Mexico because of its edible fruits. Our study explored the effect of human manipulation on levels and distribution of genetic variation in wild, silviculturally managed and cultivated sympatric populations. Total genetic variation, estimated in nine populations with five microsatellite loci, was HT = 0.658 ± 0.026 SE, which was mainly distributed within populations (HS = 0.646) with low differentiation among them (FST = 0.015). Fixation index (FIS) in all populations was positive, indicating a deficit of heterozygous individuals with respect to Hardy–Weinberg expectations. When populations were pooled by management type, the highest expected heterozygosity (HE = 0.631 ± 0.031 SE) and the lowest fixation index (FIS = 0.07) were observed in wild populations, followed by cultivated populations (HE = 0.56 ± 0.03 SE, FIS = 0.14), whereas the lowest variation was found in silviculturally managed populations (HE = 0.51 ± 0.05 SE, FIS = 0.17). Low differentiation among populations under different management types (FST 0.005, P < 0.04) was observed. A pattern of migration among neighbouring populations, suggested from isolation by distance (r2 = 0.314, P < 0.01), may have contributed to homogenizing populations and counteracting the effects of artificial selection. P. chichipe, used and managed for at least 700 generations, shows morphological differentiation, changes in breeding system and seed germination patterns associated with human management, with only slight genetic differences detected by neutral markers.
Dispersal and phylogeography of the agamid lizardAmphibolurus nobbiin fragmented and continuous habitat
Authors: DRISCOLL D. A. , HARDY C. M. 
Published: April 2005

AbstractApproximately 90% of native vegetation has been cleared for agriculture in central New South Wales, Australia. Habitat loss has reduced and fragmented populations of the agamid lizardAmphibolurus nobbi. We compared genetic structure of populations of this species in an unmodified landscape with those from small nature reserves and linear remnants in farming areas. We ask: Is there evidence for reduced dispersal and population fragmentation among farm populations? Using 2008 bp mtDNA sequences and allozyme electrophoresis, we found that small populations in farming areas had as much genetic variation as populations in nature reserves. Application of nested clade analysis (NCA) indicated isolation‐by‐distance effects among populations from uncleared areas, but not among populations within farming locations. The genetic evidence therefore implied a high level of migration in the cleared landscapes. High dispersal after fragmentation may have resulted from either a burst of movement at the time of land clearing with dragons from many sources finding refuge in a few remnants, or from ongoing rapid dispersal through unsuitable habitat. A phylogeny based on mtDNA revealed thatA. nobbipopulations in the study area are deeply divided into two reciprocally monophyletic groups. Although we did not sample the entire species range, one of these evolutionarily significant units was only detected in remnant vegetation in the agricultural landscape. Therefore, a substantial subclade of this species may be vulnerable to extinction. Our findings emphasize that local populations of widespread species can harbour important intraspecific genetic diversity, supporting the case for maintaining widespread species throughout production landscapes.
Mitochondrial and nuclear DNA phylogeography of European grayling (Thymallus thymallus): evidence for secondary contact zones in central Europe
Authors: GUM B. , GROSS R. , KUEHN R. 
Published: April 2005

AbstractMitochondrial and microsatellite DNA markers were applied to infer the phylogeography, intraspecific diversity and dynamics of the distributional history of European grayling (Thymallus thymallus) with focus on its central and northern European distribution range. Phylogenetic and nested clade analyses revealed at least four major mtDNA lineages, which evolved in geographical isolation during the Pleistocene. These lineages should be recognized as the basic evolutionary significant units (ESUs) for grayling in central and northern Europe. In addition, and in contrast to previous work on grayling, the results of Bayesian analysis of individual admixture coefficients, two‐dimensional scaling analysis and spatial analysis of molecular variance provided evidence for a high level of admixture among major lineages in contact zones between drainages (e.g. the low mountain range of Germany), most likely resulting from glacial perturbations and ancient river connections between drainages during the Pleistocene glaciations. Even within river systems, a high level of differentiation among populations was revealed as indicated by the microsatellite data. Grayling sampled from 29 sites displayed high levels of differentiation (overall FST = 0.367), a high number of private alleles and high bootstrap support for the genetic distance‐based population clusters across 12 loci. We specifically discuss our results in context of phylogeograpic studies on other European freshwater fish species with habitat preferences similar to those of grayling. Our study shows that both large‐scale phylogeographical and detailed genetic analyses on a fine scale are mandatory for developing appropriate conservation guidelines of endangered species.
Molecular scatology as a tool to study diet: analysis of prey DNA in scats from captive Steller sea lions
Authors: DEAGLE B. E. , TOLLIT D. J. , JARMAN S. N. , HINDELL M. A. , TRITES A. W. , GALES N. J. 
Published: April 2005

AbstractThe DNA of prey present in animal scats may provide a valuable source of information for dietary studies. We conducted a captive feeding trial to test whether prey DNA could be reliably detected in scat samples from Steller sea lions (Eumetopias jubatus). Two sea lions were fed a diet of fish (five species) and squid (one species), and DNA was extracted from the soft component of collected scats. Most of the DNA obtained came from the predator, but prey DNA could be amplified using prey‐specific primers. The four prey species fed in consistent daily proportions throughout the trial were detected in more than 90% of the scat DNA extractions. Squid and sockeye salmon, which were fed as a relatively small percentage of the daily diet, were detected as reliably as the more abundant diet items. Prey detection was erratic in scats collected when the daily diet was fed in two meals that differed in prey composition, suggesting that prey DNA is passed in meal specific pulses. Prey items that were removed from the diet following one day of feeding were only detected in scats collected within 48 h of ingestion. Proportions of fish DNA present in eight scat samples (evaluated through the screening of clone libraries) were roughly proportional to the mass of prey items consumed, raising the possibility that DNA quantification methods could provide semi‐quantitative diet composition data. This study should be of broad interest to researchers studying diet since it highlights an approach that can accurately identify prey species and is not dependent on prey hard parts surviving digestion.
Inferring contemporary levels of gene flow and demographic history in a local population of the leaf beetle Gonioctena olivacea from mitochondrial DNA sequence variation
Authors: MARDULYN PATRICK , MILINKOVITCH MICHEL C. 
Published: April 2005

AbstractWe have studied mitochondrial DNA variation in a local population of the leaf beetle species Gonioctena olivacea, to check whether its apparent low dispersal behaviour affects its pattern of genetic variation at a small geographical scale. We have sampled 10 populations of G. olivacea within a rectangle of 5 × 2 km in the Belgian Ardennes, as well as five populations located approximately along a straight line of 30 km and separated by distances of 3–12 km. For each sampled individual (8–19 per population), a fragment of the mtDNA control region was polymerase chain reaction‐amplified and sequenced. Sequence data were analysed to test whether significant genetic differentiation could be detected among populations separated by such relatively short distances. The reconstructed genealogy of the mitochondrial haplotypes was also used to investigate the demographic history of these populations. Computer simulations of the evolution of populations were conducted to assess the minimum amount of gene flow that is necessary to explain the observed pattern of variation in the samples. Results show that migration among populations included in the rectangle of 5 × 2 km is substantial, and probably involves the occurrence of dispersal flights. This appears difficult to reconcile with the results of a previous ecological field study that concluded that most of this species dispersal occurs by walking. While sufficient migration to homogenize genetic diversity occurs among populations separated by distances of a few hundred metres to a few kilometres, distances greater than 5 km results in contrast in strong differentiation among populations, suggesting that migration is drastically reduced on such distances. Finally, the results of coalescent simulations suggest that the star‐like genealogy inferred from the mtDNA sequence data is fully compatible with a past demographic expansion. However, a metapopulation structure alone (without the need to invoke a population expansion event) cannot be dismissed as the cause of this star shape.
Locally differentiated cryptic pigmentation in the freshwater isopod Asellus aquaticus
Authors: HARGEBY A. , STOLTZ J. , JOHANSSON J. 
Published: April 2005

AbstractA repeated pattern of background colour matching in animals is an indication that pigmentation may be cryptic. Here, we examine the relationship between pigmentation of the freshwater isopod Asellus aquaticus and background darkness in 29 lakes, wetlands and ponds in Southern Sweden. The results show that Asellus pigmentation was correlated with substrate darkness across all localities. In seven localities, in which two contrasting substrate types were noted, Asellus populations were differentiated with respect to pigmentation. These findings thus provide phenomenological support for cryptic pigmentation in Asellus. Pigmentation generally increased with body size, but the relationship between pigmentation and size differed among localities, possibly as a result of differences in correlational selection on pigmentation and size. Selection thus appears to have resulted in local differentiation over a small spatial scale, even within lakes and wetlands. This differentiation is a likely cause behind elevated phenotype variation noted in localities with two substrate types, suggesting that habitat heterogeneity promotes genetic diversity.
The influence of mating system on the intensity of parent–offspring conflict in primates
Authors: LONG T. A. F. 
Published: April 2005

AbstractAn evolutionary conflict of interest exists between parents and their offspring over the partitioning of parental investment (PI) among siblings. When the direct fitness benefits to offspring of increased PI, outweigh the inclusive fitness costs from lost future sibling fitness, selection should favour the evolution of offspring selfishness over altruism. In theory, this conflict is heightened when females are not strictly monogamous, as current offspring should be less altruistic towards future half‐siblings than they would be towards full‐siblings. Using data collected on foetal growth rate (representing prenatal PI) in primates, I test the prediction from theory that the resolution of the parent‐offspring conflict will be closer to the offspring's evolutionary optima in polyandrous species than in more monandrous species. Using phylogenetic comparative analysis, and controlling for allometry, I show that offspring are able to obtain more PI when the probability of future full‐siblings decreases, and that this is most pronounced in taxa where there is the opportunity for direct foetal access to the maternal bloodstream. These results support the hypothesis that the resolution of prenatal PI conflict is influenced by both a species’ mating system and by its placental structure.
Habitat selection behaviour links local and regional scales in aquatic systems
Authors: Resetarits William J. 
Published: April 2005

AbstractThe role of habitat selection behaviour in the assembly of natural communities is an increasingly important theme in ecology. At the same time, ecologists and conservation biologists are keenly interested in scale and how processes at scales from local to regional interact to determine species distributions and patterns of biodiversity. How important is habitat selection in generating observed patterns of distribution and diversity at multiple spatial scales? In theory, habitat selection in response to interacting species can generate both positive and negative covariances among species distributions and create the potential to link processes of community assembly across multiple scales. Here I demonstrate that habitat selection by treefrogs in response to the distribution of fish predators functions at both the regional scale among localities and the local scale among patches within localities, implicating habitat selection as a critical link between local communities and the regional dynamics of metacommunities in complex landscapes.
Impact of hormone replacement therapy on microvascular function in healthy and Type 2 diabetic postmenopausal women
Authors: Gooding K. M. , MacLeod K. M. , Spyer G. , Ewings P. , Tooke J. E. , Shore A. C. 
Published: April 2005

AbstractAims  Hormone replacement therapy (HRT) has been previously reported to modulate vascular function and cardiovascular risk. Its impact on the macrocirculation has previously been explored, however, little data is available on its impact on the microcirculation. This study aimed to determine the impact of HRT on microvascular function in healthy and Type 2 diabetic postmenopausal women (n = 20 and 17, respectively).Methods  Microvascular function was assessed by skin maximum hyperaemia, skin hyperaemic response to iontophoretically applied acetylcholine (endothelial‐dependent vasodilator) and sodium nitroprusside (endothelial‐independent vasodilator), capillary pressure and the microvascular filtration capacity. Microvascular assessments were carried out at baseline and repeated following 6 months’ oral hormone replacement therapy (1 mg oestradiol/0.5 mg norethisterone or 1 mg unopposed oestradiol for hysterectomized women).Results  Following 6 months’ therapy there were no significant changes in microvascular assessments in the healthy women. In the diabetic women there was a reduction in the skin hyperaemic response to acetylcholine [median pretreatment peak response: 1.95 (25th, 75th centiles: 1.54, 2.30) V vs. post‐treatment peak response: 1.53 (1.30, 1.91) V (P = 0.011, Wilcoxon's signed rank test)] and sodium nitroprusside [median peak response 1.59 (1.37, 1.99) vs. 1.35 (0.92, 1.63) V (P = 0.011)] with HRT, but no other changes.Conclusion  These data suggests that HRT does not affect microvascular function in healthy women, but adversely affects it in diabetic women. These findings may help to explain why HRT fails to provide the predicted cardiovascular protection, and raises the possibility that HRT influences microangiopathy progression in diabetic women.
Adverse events of herbal food supplements for body weight reduction: systematic review*
Authors: Pittler M. H. , Schmidt K. , Ernst E. 
Published: April 2005

SummaryHerbal weight‐loss supplements are marketed with claims of effectiveness. Our earlier systematic review identified data from double‐blind, randomized controlled trials for a number of herbal supplements. The aim of this systematic review was to assess all clinical evidence of adverse events of herbal food supplements for body weight reduction for which effectiveness data from rigorous clinical trials exist. We assessed Ephedra sinica, Garcinia cambogia, Paullinia cupana, guar gum, Plantago psyllium, Ilex paraguariensis and Pausinystalia yohimbe. Literature searches were conducted on Medline, Embase, Amed and The Cochrane Library. Data were also requested from the spontaneous reporting scheme of the World Health Organization. We hand‐searched relevant medical journals and our own files. There were no restrictions regarding the language of publication. The results show that adverse events including hepatic injury and death have been reported with the use of some herbal food supplements. For herbal ephedra and ephedrine‐containing food supplements an increased risk of psychiatric, autonomic or gastrointestinal adverse events and heart palpitations has been reported. In conclusion, adverse events are reported for a number of herbal food supplements, which are used for reducing body weight. Although the quality of the data does not justify definitive attribution of causality in most cases, the reported risks are sufficient to shift the risk–benefit balance against the use of most of the reviewed herbal weight‐loss supplements. Exceptions are Garcinia cambogia and yerba maté, which merit further investigation.
Comparison of overweight and obesity prevalence in school‐aged youth from 34 countries and their relationships with physical activity and dietary patterns
Authors: Janssen I. , Katzmarzyk P. T. , Boyce W. F. , Vereecken C. , Mulvihill C. , Roberts C. , Currie C. , Pickett W. ,   The Health Behaviour in School‐Aged Children Obesity Working Group
Published: April 2005

SummaryThe purposes of this systematic review were to present and compare recent estimates of the prevalence of overweight and obesity in school‐aged youth from 34 countries and to examine associations between overweight and selected dietary and physical activity patterns. Data consisted of a cross‐sectional survey of 137 593 youth (10–16 years) from the 34 (primarily European) participating countries of the 2001–2002 Health Behaviour in School‐Aged Children Study. The prevalence of overweight and obesity was determined based on self‐reported height and weight and the international child body mass index standards. Logistic regression was employed to examine associations between overweight status with selected dietary and physical activity patterns. The two countries with the highest prevalence of overweight (pre‐obese + obese) and obese youth were Malta (25.4% and 7.9%) and the United States (25.1% and 6.8%) while the two countries with the lowest prevalence were Lithuania (5.1% and 0.4%) and Latvia (5.9% and 0.5%). Overweight and obesity prevalence was particularly high in countries located in North America, Great Britain, and south‐western Europe. Within most countries physical activity levels were lower and television viewing times were higher in overweight compared to normal weight youth. In 91% of the countries examined, the frequency of sweets intake was lower in overweight than normal weight youth. Overweight status was not associated with the intake of fruits, vegetables, and soft drinks or time spent on the computer. In conclusion, the adolescent obesity epidemic is a global issue. Increasing physical activity participation and decreasing television viewing should be the focus of strategies aimed at preventing and treating overweight and obesity in youth.
Bacillus subtilis
Paraquat Resistance Is Directed by σ
M
, an Extracytoplasmic Function Sigma Factor, and Is Conferred by YqjL and BcrC
Authors: Cao Min , Moore Charles M. , Helmann John D. 
Published: April 2005

ABSTRACT

A
Bacillus subtilis sigM
null mutant, lacking the extracytoplasmic function σ
M
protein, was sensitive to paraquat (PQ), a superoxide-generating reagent, but not to the redox stress-inducing compounds hydrogen peroxide, cumene hydroperoxide,
t
-butyl hydroperoxide, or diamide. Surprisingly, a
sigM
mutant was only sensitive to superoxide-generating compounds with a dipyridyl ring such as PQ, ethyl viologen, benzyl viologen, and diquat but not to menadione, plumbagin, pyrogallol, or nitrofurantoin. Mutational analysis of candidate σ
M
-regulated genes revealed that both YqjL, a putative hydrolase, and BcrC, a bacitracin resistance protein, were involved in PQ resistance. Expression of
yqjL
, but not
bcrC
, from a xylose-inducible promoter restored PQ resistance to the
sigM
mutant.
Changes in the Extracellular Proteome Caused by the Absence of the
bldA
Gene Product, a Developmentally Significant tRNA, Reveal a New Target for the Pleiotropic Regulator AdpA in
Streptomyces coelicolor
Authors: Kim Dae-Wi , Chater Keith , Lee Kye-Joon , Hesketh Andy 
Published: April 2005

ABSTRACT

The extracellular proteome of
Streptomyces coelicolor
grown in a liquid medium was analyzed by using two-dimensional gel electrophoresis and matrix-assisted laser desorption ionization-time of flight peptide mass fingerprint analysis. Culture supernatants became protein rich only after rapid growth had been completed, supporting the idea that protein secretion is largely a stationary phase phenomenon. Out of about 600 protein spots observed, 72 were characterized. The products of 47 genes were identified, with only 11 examples predicted to be secreted proteins. Mutation in
bldA
, previously known to impair the stationary phase processes of antibiotic production and morphological differentiation, also induced changes in the extracellular proteome, revealing even greater pleiotropy in the
bldA
phenotype than previously known. Four proteins increased in abundance in the
bldA
mutant, while the products of 11 genes, including four secreted proteins, were severely down-regulated. Although
bldA
encodes the only tRNA capable of efficiently translating the rare UUA (leucine) codon, none of the latter group of genes contains an in-frame TTA. SCO0762, a serine-protease inhibitor belonging to the
Streptomyces
subtilisin inhibitor family implicated in differentiation in other streptomycetes, was completely absent from the
bldA
mutant. This dependence was shown to be mediated via the TTA-containing regulatory gene
adpA
, also known as
bldH
, a developmental gene that is responsible for the effects of
bldA
on differentiation. Mutation of the SCO0762 gene abolished detectable trypsin-protease inhibitory activity but did not result in any obvious morphological defects.