bluuebunny/crossref_metadata_2025_split huggingface dataset:
Surface Morphologies of Magnesium Vanadium Oxide, Mg2‐xV1+xO4
Authors: OSHIMA HIROTOSHI 
Published: June 2006

The microscopic appearance of the particle surfaces of magnesium vanadium oxide, Mg2‐xV1+xO4, loose powders prepared in various atmospheres at 1200°C was studied. The surface morphology, observed by SEM, was dependent on the V4+ content, and three typical features were distinguished at the following x values:

0.75≤x<1.00; rounded crystals with smooth surfaces
0.55≤x≤0.75; edged crystals with stepped surfaces
x≤0.55; coarse crystals with rough surfaces
Risk and protective factors for meningococcal disease in adolescents: matched cohort study
Authors: Reading Richard 
Published: June 2006

.

Tully J.,
Viner R.M.,
Coen P.G.,
Stuart J.M.,
Zambon M.,
Peckham C.,
Booth C.,
Klein N.,
Kaczmarski E. &
Booy R.
(
2006
)

,
332
,
445
–
450
.
Objective  To examine biological and social risk factors for meningococcal disease in adolescents.Design  Prospective, population‐based, matched cohort study with controls matched for age and sex in 1:1 matching. Controls were sought from the general practitioner.Setting  Six contiguous regions of England, which represent some 65% of the country’s population.Participants  Fifteen‐to‐nineteen‐year‐olds with meningococcal disease recruited at hospital admission in six regions (representing 65% of the population of England) from January 1999 to June 2000, and their matched controls.Methods  Blood samples and pernasal and throat swabs were taken from case patients at admission to hospital and from cases and matched controls at interview. Data on potential risk factors were gathered by confidential interview. Data were analysed by using univariate and multivariate conditional logistic regression.Results  A total of 144 case–control pairs were recruited [74 male (51%); median age 17.6 years]. In total, 114 cases (79%) were confirmed microbiologically. Significant independent risk factors for meningococcal disease were history of preceding illness (matched odds ratio 2.9, 95% confidence interval 1.4–5.9), intimate kissing with multiple partners (3.7, 1.7–8.1), being a university student (3.4, 1.2–10) and preterm birth (3.7, 1.0–13.5). Religious observance (0.09, 0.02–0.6) and meningococcal vaccination (0.12, 0.04–0.4) were associated with protection.Conclusions  Activities and events increasing risk for meningococcal disease in adolescence are different from those in childhood. Students are at higher risk. Altering personal behaviours could moderate the risk. However, the development of further effective meningococcal vaccines remains a key public health priority.
Multiple paternity in wild‐caughtDrosophila mojavensis
Authors: GOOD JEFFREY M. , ROSS CHARLES L. , MARKOW THERESE A. 
Published: June 2006

AbstractFemale remating frequency and sperm allocation patterns can strongly influence levels of sperm competition and reproductive success in natural populations. In the laboratory,Drosophila mojavensismales transfer very few sperm per copulation and females remate often, suggesting multiple paternity should be common in nature. Here, we examine female sperm loads, incidence of multiple paternity, and sperm utilization by genotyping progeny from 20 wild‐caught females at four highly polymorphic microsatellite loci. Based on indirect paternity analyses of 814 flies, we found evidence for high levels of multiple paternity coupled with relatively low reproductive output, consistent with the high levels of female remating predicted in this sperm‐limited species. Overall, we found little evidence for last ‐ male sperm precedence though some temporal variation in sperm utilization was observed, consistent with laboratory findings.
Multiple nuclear gene sequences identify phylogenetic species boundaries in the rapidly radiating clade of Mexican ambystomatid salamanders
Authors: WEISROCK DAVID W. , SHAFFER H. BRADLEY , STORZ BRIAN L. , STORZ SHONNA R. , VOSS S. RANDAL 
Published: June 2006

AbstractDelimiting the boundaries of species involved in radiations is critical to understanding the tempo and mode of lineage formation. Single locus gene trees may or may not reflect the underlying pattern of population divergence and lineage formation, yet they constitute the vast majority of the empirical data in species radiations. In this study we make use of an expressed sequence tag (EST) database to perform nuclear (nDNA) and mitochondrial (mtDNA) genealogical tests of species boundaries inAmbystoma ordinarium, a member of an adaptive radiation of metamorphic and paedomorphic salamanders (theAmbystoma tigrinumcomplex) that have diversified across terrestrial and aquatic environments. Gene tree comparisons demonstrate extensive nonmonophyly in the mtDNA genealogy ofA. ordinarium, while seven of eight independent nuclear loci resolve the species as monophyletic or nearly so, and diagnose it as a well‐resolved genealogical species. A differential introgression hypothesis is supported by the observation that westernA. ordinariumlocalities contain mtDNA haplotypes that are identical or minimally diverged from haplotypes sampled from a nearby paedomorphic species,Ambystoma dumerilii, while most nDNA trees place these species in distant phylogenetic positions. These results provide a strong example of how historical introgression can lead to radical differences between gene trees and species histories, even among currently allopatric species with divergent life history adaptations and morphologies. They also demonstrate how EST‐based nuclear resources can be used to more fully resolve the phylogenetic history of species radiations.
‘Sax‐sess’— genetics of primary succession in a pioneer species on two parallel glacier forelands
Authors: RAFFL C. , SCHÖNSWETTER P. , ERSCHBAMER B. 
Published: June 2006

AbstractThe primary succession on glacier forelands is characterized by a sequence of early and late successional species, but whether there is also a chronosequence at the intraspecific, genetic level is a matter of debate. Two opposing hypotheses differ in their prediction of genetic diversity in colonizing populations due to founder effects and postcolonization gene immigration. The development of genetic diversity in the pioneer Saxifraga aizoides was investigated along a successional gradient on two parallel glacier forelands, in order to test whether populations from older successional stages were less genetically diverse than populations from younger successional stages, and to locate the sources of the propagules that originally colonized new glacier foreland. Genetic diversity was determined with amplified fragment length polymorphisms, and potential sources of colonizing propagules were assessed via assignment tests. Our results indicate considerable postcolonization gene flow among populations on glacier forelands, since population differentiation was low and genetic diversity within populations was significantly higher. Molecular diversity and differentiation of populations did not develop linearly. Dispersal events within the glacier foreland, from the adjacent valley slopes, and from parallel glacier valleys were identified. In summary, it seems that the colonization of glacier forelands in the European Alps is highly dynamic and stochastic.
Patterns of genetic connectivity among anchialine habitats: a case study of the endemic Hawaiian shrimpHalocaridina rubraon the island of Hawaii
Authors: SANTOS SCOTT R. 
Published: June 2006

AbstractAnchialine habitats, landlocked bodies of mixohaline water that fluctuate with the tides but have no surface connection to the sea, are known from around the world. Many anchialine organisms have widespread distributions and it has been hypothesized that high levels of gene flow and low levels of genetic differentiation are characteristic of populations from these habitats. However, the generality of this hypothesis requires further assessment, particularly in light of the significant negative impact these habitats and their biota have experienced from anthropogenic causes. This study investigated the population structure and demography of an endemic Hawaiian anchialine species, the atyid shrimpHalocaridina rubra, using mitochondrial cytochromecoxidase subunit I (COI) gene sequences. A survey of 305 individuals from 16 populations collected on the island of Hawaii revealed 135 haplotypes. These haplotypes belonged to one of two divergent (2.7–4.9%) lineages; notably, no haplotypes were shared between the two coasts of the island. Along each coast, strong subdivision and little to no gene flow occurs between populations separated by > 30 km. The population structure and demography ofH. rubraon Hawaii are influenced by regional hydrology, geology, volcanism and two distinct colonization events of the island. Thus,H. rubraon Hawaii demonstrates that populations of endemic anchialine organisms may exhibit significant levels of genetic structure and restricted levels of gene flow over limited geographic scales. This report brings novel insight into the biology of anchialine organisms and has important implications for the future management of these habitats and their biota.
Recombination and selection shape the molecular diversity pattern of nitrogen‐fixing Sinorhizobium sp. associated to Medicago
Authors: BAILLY XAVIER , OLIVIERI ISABELLE , DE MITA STÉPHANE , CLEYET‐MAREL JEAN‐CLAUDE , BÉNA GILLES 
Published: June 2006

AbstractWe investigate the genetic structure and molecular selection pattern of a sympatric population of Sinorhizobium meliloti and Sinorhizobium medicae. These bacteria fix nitrogen in association with plants of the genus Medicago. A set of 116 isolates were obtained from a soil sample, from root nodules of three groups of plants representing among‐species, within‐species and intraline diversity in the Medicago genus. Bacteria were characterized by sequencing at seven loci evenly distributed along the genome of both Sinorhizobium species, covering the chromosome and the two megaplasmids. We first test whether the diversity of host plants influence the bacterial diversity recovered. Using the same data set, we then analyse the selective pattern at each locus. There was no relationship between the diversity of Medicago plants that were used for sampling and the diversity of their symbionts. However, we found evidence of selection within each of the two main symbiotic regions, located on the two different megaplasmids. Purifying selection or a selective sweep was found to occur in the nod genomic region, which includes genes involved in nodulation specificity, whereas balancing selection was detected in the exo region, close to genes involved in exopolysaccharide production. Such pattern likely reflects the interaction between host plants and bacterial symbionts, with a possible conflict of interest between plants and cheater bacterial genotypes. Recombination appears to occur preferentially within and among loci located on megaplasmids, rather than within the chromosome. Thus, recombination may play an important role in resolving this conflict by allowing different selection patterns at different loci.
Community‐based study to assess the efficacy of DEC plus ALB against DEC alone on bancroftian filarial infection in endemic areas in Tamil Nadu, south India
Authors: Rajendran R. , Sunish I. P. , Mani T. R. , Munirathinam A. , Arunachalam N. , Satyanarayana K. , Dash A. P. 
Published: June 2006

SummaryAs part of the Global Programme for Elimination of Lymphatic Filariasis (GPELF), India is implementing mass drug administration (MDA) with annual single dose of diethylcarbamazine (DEC) with and without albendazole (ALB). The impact of MDAs on filarial infections and soil‐transmitted helminth (STH) infections was assessed during a 3‐year period in two communities, one with DEC + ALB and the other with DEC alone. Prior to each MDA (during 2001, 2002 and 2003), filarial indices (microfilaraemia and antigenaemia) were assessed from blood samples of 450–650 persons aged 2–25 years and STH infections in stool samples (Kato–Katz method) from 325 to 500 children aged 9–10 years. Mosquitoes resting indoors were collected to determine the filarial infection status. The microfilaraemia prevalence decreased significantly (P < 0.05) in both arms, with the highest decline in the DEC + ALB arm (72%vs. 51%). Decline in micrefilaria intensity was also higher in the DEC + ALB arm (81.4%vs. 48.5%). In this arm alone, the antigenaemia prevalence was reduced significantly (62%; P < 0.001). The reduction in STH prevalence was lower in the DEC alone arm (6.5%; NS) than in the DEC + ALB arm (70.9%; P < 0.001). Also, the egg reduction in DEC alone arm was only half that of DEC + ALB arm (49%vs. 97%). Our community‐based follow‐up study showed higher and sustained benefits with regard to filarial and STH infections for the two‐drug arm over the DEC alone arm. The trends suggest that at least 10 MDAs may be necessary to achieve the goal of elimination.
Pyoderma gangrenosum occurring near an arteriovenous dialysis shunt
Authors: Sangiray Hayri , Nguyen Josephine C. , Turiansky George W. , Norwood Christopher 
Published: June 2006

AbtractPyoderma gangrenosum (PG) is an uncommon cutaneous disease of unknown etiology. In 50 percent of affected patients, PG is associated with systemic disease including inflammatory bowel disease, arthritis, and hematologic malignancies.1 Diagnosis of PG is based on clinical presentation, histopathology and on the exclusion of other diseases that can produce clinically similar lesions, e.g. infection, vasculitis, malignancy, collagen vascular diseases, diabetes, and trauma. Four variants of PG have been described: ulcerative, pustular, bullous, and vegetative.2 We report a woman with renal failure who developed PG in the absence of any obvious triggering trauma in a distinctive unilateral crop just distal to an arteriovenous dialysis shunt.
HLA‐C molecular characterization of a Lebanese population and genetic structure of 39 populations from Europe to India–Pakistan
Authors: Buhler S. , Megarbane A. , Lefranc G. , Tiercy J.‐M. , Sanchez‐Mazas A. 
Published: June 2006

AbstractLebanon is located at a continental crossroad between Europe, Africa, and Asia. This region has been the center of wide‐scale movements of populations as well as the theater of genetic and cultural trade off among neighboring populations. In this study, HLA‐C alleles were characterized by a PCR‐SSOP (sequence‐specific oligonucleotide probes) hybridization protocol in a sample of 97 Lebanese. A total of 23 alleles were identified with four predominant, Cw*0401, Cw*0602, Cw*0701/06, and Cw*1203, accounting for almost 60% of HLA‐C allele frequencies. We included the Lebanese data into a broad analysis of the HLA‐C genetic structure of a large set of populations located in Europe, the Middle East, and the Indian subcontinent. Our results indicate that Lebanese exhibit an intermediate genetic profile among the populations from the Middle East, which constitute a rather homogeneous genetic group. In Europe, a high correlation coefficient is found between genetic and geographic distances. In this continent, we also identified a significant genetic frontier following a north‐east to south‐west axis. This frontier cuts through the Alps and the Pyrenees, thus separating the north‐western European populations from those located in the eastern and Mediterranean areas. Finally, the populations from India – Pakistan are very heterogeneous, particularly the Dravidians. Their differentiation has probably been caused by rapid genetic drift under complex influences of cultural, linguistic, and/or religious barriers. Overall, the results show that the HLA‐C genetic patterns of these three geographic regions, i.e., the Middle East, Europe, and India – Pakistan, have been shaped by very different genetic histories.
Morphological and functional characterization of a pancreatic β‐cell line microencapsulated in sodium cellulose sulfate/poly(diallyldimethylammonium chloride)
Authors: Stadlbauer V. , Stiegler P. B. , Schaffellner S. , Hauser O. , Halwachs G. , Iberer F. , Tscheliessnigg K. H. , Lackner C. 
Published: June 2006

Abstract:  Background:  Late diabetic complications cannot be prevented totally by current antidiabetic strategies. Therefore, new therapeutic concepts of insulin replacement such as pancreas transplantation are evolving. Due to the shortage of human donor organs, transplantation of microencapsulated xenogeneic pancreatic islet cells has attracted considerable attention. Sodium cellulose sulfate/poly(diallyldimethylammonium chloride) (NaCS/PDADMAC) is a material with favorable biogenic properties that has been used for microencapsulation of various cell types. However, there are no data on the suitability of NaCS/PDADMAC for microencapsulation of pancreatic β‐cells.Material and methods:  Cell growth and viability of NaCS/PDADMAC‐microencapsulated HIT‐T15 cells, an immortalized hamster pancreatic β‐cell line, were assessed using a dimethylthiazol‐diphenyltetrazoliumbromide (MTT)‐based cell growth determination kit and apoptosis was detected by antibodies against activated caspase 3. Glucose‐dependent insulin secretion was assessed with ELISA and the uptake of glucose was measured using fluorescence‐labeled glucose.Results:  Statistical analysis revealed no differences in glucose‐dependent cell proliferation, insulin secretion and glucose uptake between non‐microencapsulated and microencapsulated HIT‐T15 cells. Stimulation of HIT‐T15 cells with glucose (100 mg/ml) resulted in a biphasic insulin secretion response.Conclusion:  Microencapsulation of HIT‐T15 cells in NaCS/PDADMAC does not influence cell proliferation, insulin secretion and glucose uptake. Our results indicate that NaCS/PDADMAC is well suited for microencapsulation of pancreatic β‐cells.
Human NK cells can lyse porcine endothelial cells independent of their expression of Galα(1,3)‐Gal and killing is enhanced by activation of either effector or target cells
Authors: Horvath‐Arcidiacono Judith A. , Porter Cynthia M. , Bloom Eda T. 
Published: June 2006

Abstract:  Background:  Xenotransplantation of pig organs may provide an approach to alleviate the severe shortage of human organs. Natural antibodies against Galα(1,3)‐Gal (αGal) epitopes cause hyperacute rejection of pig organs in primates. However, evidence for the role of αGal in the natural killer (NK) cell‐mediated xenoresponse has been contradictory.Methods:  We investigated the recognition of αGal by human NK cells using endo‐β‐galactosidase C, an enzyme that cleaves αGal, and endothelial cells (EC) from α1,3‐galactosyltransferase null pigs that do not synthesize αGal. Endo‐β‐galactosidase C treatment variably reduced the susceptibility of porcine EC to lysis by fresh human NK cells.Results:  Removal of αGal from porcine EC using endo‐β‐galactosidase C, produced variable results, i.e. cytotoxicity was decreased in half of the human NK cell donors tested. The two EC strains from αGal−/− pigs were marginally, and not significantly, less susceptible to lysis by naïve human NK cells compared with αGal‐expressing cells obtained from animals from the same herd, but these differences were not statistically significant (P > 0.10). Treatment of porcine EC with recombinant human tumor necrosis factor (TNF)‐α, which is known to activate porcine EC, enhanced the susceptibility of all target cells to lysis by fresh human NK cells. Surface expression of MHC or adhesion molecules on αGal−/− cells, compared with wild type cells, showed no consistent difference in either MHC or adhesion molecules CD106 (VCAM‐1), CD31 (PECAM) or CD62E (E‐selectin), either with or without TNF‐α stimulation, that could explain the differential susceptibility to lysis. Strikingly, all αGal−/− and wild type EC exhibited similar susceptibility to human NK cells that had been cultured for 5 days with or without interleukin‐2.Conclusions:  These findings demonstrate that human NK cells can kill porcine targets in the absence of αGal, and donor variability plays a major role in whether αGal has a role in determining susceptibility of porcine EC to lysis. Moreover, susceptibility to lysis of αGal null EC is enhanced to the level of wild type EC by activation of either effector or target cells. Elimination of αGal alone from source pigs will be insufficient to circumvent the NK cell mediated destruction of porcine EC.
Genetic architecture of traits associated with serpentine adaptation of Silene vulgaris
Authors: Bratteler M. , Lexer C. , Widmer A. 
Published: June 2006

Abstract
Serpentine soils provide a difficult substrate for plant colonization and growth and therefore represent an ideal system for studying the genetics of habitat adaptation and the evolution of plant-ecotypes. Using an F2 mapping population derived from an intraspecific cross between a serpentine and a nonserpentine ecotype of Silene vulgaris, the genetic architecture of seven morphological, physiological and life-history traits was explored. A quantitative trait locus (QTL) analysis identified 23 QTLs, 15 of which were classified as major QTLs. The observed genetic architecture suggests that traits potentially involved in habitat adaptation are controlled by few genes of major effect and have evolved under consistent directional selection. Several linkage groups harboured overlapping QTLs for different traits, which can be due to either pleiotropy or linkage. The potential roles of these factors and of the time available for habitat adaptation and ecological speciation on serpentine are discussed.
Protein sequences of linked genes are highly conserved in two bacterial species
Authors: Theodosiou T. , Iliopoulos I. 
Published: June 2006

Abstract
It has been shown that proteins encoded by linked genes have similar rates of evolution and that clusters of essential genes are found in regions with low recombination rates. We show here that proteins encoded by linked genes in two closely related bacterial species, namely Escherichia coli K12 and Salmonella typhimurium LT2, evolve more slowly when compared with proteins encoded by genes that are not linked as assessed by protein sequence similarity. The proteins encoded by the identified linked genes share an average sequence identity of 82.5% compared with a 46.5% identity of proteins encoded by genes that are not linked.
EFFECT OF NITRIC OXIDE ON THE HYPOGLYCAEMIC PHASE OF ENDOTOXAEMIA
Authors: Engin Atilla , Zemheri Mahmut , Bukan Neslihan , Memiş Leyla 
Published: June 2006

Background:  Depletion of liver glycogen stores and subsequent hypoglycaemia is one of the unresolved features in endotoxaemia. The aim of this study was to elucidate the effect of L‐arginine treatment on the glucose requirement and impending liver damage during the hypoglycaemic period of endotoxaemia.Methods:  Sixty‐three of 98 male Wistar rats were assigned equally to one of three groups and received saline as control, L‐arginine as selective nitric oxide donor or NG‐nitro‐L‐arginine methyl ester for non‐selective inhibition of nitric oxide production 1 h before endotoxin injection. At 2, 4 and 6 h following endotoxin, blood and liver samples were collected. Plasma nitrite plus nitrate, glucose, insulin and glucagon concentrations and total liver‐reduced glutathione were measured. Hepatocellular glycogen content and liver damage were assessed simultaneously by histological quantification. An additional seven rats were allocated to each group and subjected to i.v. glucose tolerance test during the hypoglycaemic period.Results:  Increased levels of endogenousglutathione (P = 0.003) and excess nitric oxide (P = 0.002) apparently protected the liver from endotoxin‐induced injury by preserving the optimum glucose consumption rate, insulin/glucagon ratio and liver glycogen in L‐arginine‐plus‐endotoxin‐treated group. Furthermore, expected hypoglycaemic period was not observed in these animals.Conclusion:  Exogenous L‐arginine prevented the excessive liver glycogen release without inhibiting glucose consumption while decreasing hepatic injury during the expected hypoglycaemic phase of endotoxaemia.