bluuebunny/crossref_metadata_2025_split huggingface dataset:
Does widowhood affect memory performance of older persons?
Authors: AARTSEN MARJA J. , VAN TILBURG THEO , SMITS CAROLIEN H. M. , COMIJS HANNIE C. , KNIPSCHEER KEES C. P. M. 
Published: January 2005

Background. The loss of a spouse has been found to have a negative effect on physical and mental health and leads to increased mortality. Whether conjugal bereavement also affects memory functioning has largely been unexamined. The present study investigates the effect of widowhood on memory functioning in older persons.Method. The sample consisted of 474 married women and 690 married men aged 60–85 years in 1992, followed up in 1995 and 1998. During the study 135 (28%) of the women and 69 (10%) of the men lost their spouse. Linear regression analysis was used to examine whether widowed men and women differed from those who had not been widowed in rate of memory change over 6 years. Cross-domain latent-change models were subsequently used to evaluate the extent to which changes in memory are related to changes in other domains of functioning that may be affected by widowhood.Results. Older adults who lost a spouse during follow-up showed a greater decline in memory over 6 years than those who remained married. A higher level of depressive symptoms at baseline was related to lower levels of memory functioning and a greater decline. Memory decline was unrelated to changes in depressive symptoms and physical health.Conclusions. Loss of the spouse is related to a greater decline in memory in older adults. The absence of an association with physical functioning and the weak association with mental functioning suggest that losing a spouse has an independent effect on memory functioning.
Memory and verbal learning functions in twins with bipolar-I disorder, and the role of information-processing speed
Authors: KIESEPPÄ TUULA , TUULIO-HENRIKSSON ANNAMARI , HAUKKA JARI , VAN ERP THEO , GLAHN DAVID , CANNON TYRONE D. , PARTONEN TIMO , KAPRIO JAAKKO , LÖNNQVIST JOUKO 
Published: January 2005

Background. Euthymic bipolar-I disorder (BP I) patients and their siblings have shown impairments in verbal learning and memory functions compared with controls, suggesting that these impairments may be genetic in origin. Reduced information-processing speed has been associated with impaired memory in the elderly, and recently in schizophrenia. The authors compared verbal learning and memory functioning in twins with BP I and co-twins to control twins, and examined whether the observed deficits are related to information-processing speed.Method. Finnish Medical and Population Registers and Twin Cohorts were used to identify the BP I and control twins. Neuropsychological tests assessing verbal learning and memory, working memory, facial recognition, visual memory, and information-processing speed were administered to 26 BP I twins, 19 non-bipolar co-twins, and 114 controls. Group differences were analyzed by generalized estimation equation modeling.Results. BP I patients, but not co-twins, showed impairments in all memory tests compared with controls. Female co-twins showed impairment in verbal learning and memory. Information-processing speed had a significant effect on encoding and learning efficiency.Conclusions. This study showed for the first time that information-processing speed is related to memory functioning and verbal learning in BP I in a population-based, representative and euthymic sample. Furthermore, the data support the view that defects in verbal memory may be related to the genetic factors predisposing to BP I in females.
Bone marrow as a source of circulating CXCR4+ tissue‐committed stem cells
Authors: Kucia Magda , Ratajczak Janina , Ratajczak Mariusz Z. 
Published: January 2005

AbstractSeveral studies have suggested that adult haematopoietic stem cells (HSCs) may be capable of transdifferentiating across tissue‐lineage boundaries, giving rise to the concept that these stem cells are plastic in their differentiative capacity. This topic created much excitement in the scientific community, with the prospect of employing HSCs in tissue/organ regeneration (e.g. heart infarct, stroke, liver damage) as an alternative to multipotent embryonic stem cells. However, recent observations, and several alternative explanations of previously published data (e.g. cell fusion, epigenetic changes), do not support the concept of HSC plasticity. Our recent studies, in which we employed chemotactic isolation to a stromal‐cell‐derived‐factor‐1 (SDF‐1) gradient combined with real‐time reverse transcriptase (RT)‐PCR/immuno‐histochemical analyses, revealed that bone marrow (BM) contains a highly mobile population of CXCR4+ cells that express mRNA/proteins for various markers of early tissue‐committed stem cells (TCSCs). Based on this we postulate that the BM is not only a home for HSCs, but also a ‘hideout’ for non‐haematopoietic CXCR4+ TCSCs, and we suggest that their presence in BM tissue should be considered before experimental evidence is interpreted simply as transdifferentiation/plasticity of HSCs. Furthermore, our observation that the number of TCSCs is the highest in BM of young animals and decreases with age provides a novel insight into aging, and may explain why the regeneration process becomes less effective in older individuals.
The Protein Kinase Resource: everything you always wanted to know about protein kinases but were afraid to ask
Authors: Petretti Clotilde , Prigent Claude 
Published: January 2005

AbstractProtein kinases and phosphatases play crucial roles in all the major cellular processes, such as signal transduction, cell differentiation, cell proliferation and cell cycle progression. Protein phosphorylation or dephosphorylation can form the basis of many critical processes, including enzyme activation or inactivation, protein localization and protein degradation. Given the importance of protein kinases to cellular development and function, it is critical that there are effective ways of disseminating information on protein kinases to the research community. This review describes such a web resource, ‘The Protein Kinase Resource’ (http:pkr.sdsc.eduhtmlindex.shtml), which serves as a repository for cellular and molecular data on protein kinases.
Preservation of a transgenic strain of the sawfly, Athalia rosae (Hymenoptera) by artificial fertilization using cryopreserved sperm
Authors: Hatakeyama M. , Sumitani M. 
Published: January 2005

AbstractGermline transformation using a piggyBac‐derived vector is feasible in the sawfly, Athalia rosae. A previously generated transgenic line carrying green fluorescence protein (GFP) genes as reporters was successfully maintained and preserved without consecutive rearing. Sperm taken from males that were frozen directly in liquid nitrogen and stored at −80 °C for a year were microinjected into mature unfertilized eggs dissected from female ovaries. A fraction of the sperm‐injected eggs was fertilized and developed into diploid females, and all of them expressed GFP. Haploid male progeny from these females segregated into GFP‐positive and GFP‐negative individuals in a ratio of 1 : 1 indicating heterozygosity of the parental females. The GFP genes were stably inherited staying at the location where they were originally integrated.
Tissue localization and regulation by juvenile hormone of human allergen Bla g 4 from the German cockroach,Blattella germanica(L.)
Authors: Fan Y. , Gore J. C. , Redding K. O. , Vailes L. D. , Chapman M. D. , Schal C. 
Published: January 2005

AbstractThe German cockroach,Blattella germanica(L.), produces several potent protein aeroallergens, including Bla g 4, a ∼20 kDa lipocalin. RT‐PCR, Northern analyses andin situhybridization showed that Bla g 4 is expressed only in the adult male reproductive system. Western blotting and ELISA with rBla g 4 antiserum detected immunoreactivity in the utricles and the conglobate gland, but not in other tissues of the male reproductive system. The Bla g 4 protein content of males increased from adult emergence to day 14, but during copulation Bla g 4 was depleted in the male and transferred to the female within the spermatophore. Topical application of juvenile hormone III stimulated Bla g 4 production by both conglobate gland and utricles.
The mosquito Aedes aegypti (L.) leucokinin receptor is a multiligand receptor for the three Aedes kinins
Authors: Pietrantonio P. V. , Jagge C. , Taneja‐Bageshwar S. , Nachman R. J. , Barhoumi R. 
Published: January 2005

AbstractA cDNA cloned from Aedes aegypti (L.) (Aedae) female Malpighian tubule (AY596453) encodes a 584 amino acid residue protein (65.2 kDa) predicted as a G protein‐coupled receptor and orthologue of the drosokinin receptor from Drosophila melanogaster and highly similar to the tick Boophilus microplus myokinin receptor (AF228521). Based on the similarity to this Aedes sequence, we also propose a correction for the Anopheles gambiae protein sequence EAA05450. When expressed in CHO‐K1 cells, the Aedes receptor behaved as a multiligand receptor and functionally responded to concentrations ≥ 1 nm of Aedae kinins 1–3, respectively, as determined by a calcium bioluminescence plate assay and single cell intracellular calcium measurements by confocal fluorescence cytometry. Estimates of EC50 values by the plate assay were 16.04 nm for Aedae‐K‐3, 26.6 nm for Aedae‐K‐2 and 48.8 nm for Aedae‐K‐1 and were statistically significantly different. These results suggest that the observed differences in physiological responses to the three Aedes kinins in the Aedes isolated Malpighian tubule reported elsewhere could now be explained by differences in intracellular signalling events triggered by the different peptides on the same receptor and not necessarily due to the existence of various receptors for the three Aedes kinins.
Genetic diversity and differentiation of central European freshwater pearl mussel (Margaritifera margaritifera L.) populations: implications for conservation and management
Authors: GEIST JUERGEN , KUEHN RALPH 
Published: January 2005

AbstractDespite the fact that mollusc species play an important role in many aquatic ecosystems, little is known about their biodiversity and conservation genetics. Freshwater pearl mussel (Margaritifera margaritifera L.) populations are seriously declining all over Europe and a variety of conservation programs are being established to support the remaining endangered central European populations. In order to provide guidelines for conservation strategies and management programs, we investigated the genetic structure of 24 freshwater pearl mussel populations originating from five major central European drainages including Elbe, Danube, Rhine, Maas and Weser, representing the last and most important populations in this area. We present a nondestructive sampling method of haemolymph for DNA analyses, which is applicable for endangered bivalves. The analyses of nine microsatellite loci with different levels of polymorphism revealed a high degree of fragmented population structure and very different levels of genetic diversity within populations. These patterns can be explained by historical and demographic effects and have been enforced by anthropogenic activities. Even within drainages, distinct conservation units were detected, as revealed from high FST values, private alleles and genetic distance measures. Populations sampled close to contact zones between main drainage systems showed lowest levels of correct assignment to present‐day drainage systems. Populations with high priority for conservation should not only be selected by means of census population size and geographical distance to other populations. Instead, detailed genetic analyses are mandatory for revealing differentiation and diversity parameters, which should be combined with ecological criteria for sustainable conservation and recovery programs.
Patterns of genetic diversity and migration in increasingly fragmented and declining orang‐utan (Pongo pygmaeus) populations from Sabah, Malaysia
Authors: GOOSSENS B. , CHIKHI L. , JALIL M. F. , ANCRENAZ M. , LACKMAN‐ANCRENAZ I. , MOHAMED M. , ANDAU P. , BRUFORD M. W. 
Published: January 2005

AbstractWe investigated the genetic structure within and among Bornean orang‐utans (Pongo pygmaeus) in forest fragments of the Lower Kinabatangan flood plain in Sabah, Malaysia. DNA was extracted from hair and faecal samples for 200 wild individuals collected during boat surveys on the Kinabatangan River. Fourteen microsatellite loci were used to characterize patterns of genetic diversity. We found that genetic diversity was high in the set of samples (mean HE = 0.74) and that genetic differentiation was significant between the samples (average FST = 0.04, P < 0.001) with FST values ranging from low (0.01) to moderately large (0.12) values. Pairwise FST values were significantly higher across the Kinabatangan River than between samples from the same river side, thereby confirming the role of the river as a natural barrier to gene flow. The correlation between genetic and geographical distance was tested by means of a series of Mantel tests based on different measures of geographical distance. We used a Bayesian method to estimate immigration rates. The results indicate that migration is unlikely across the river but cannot be completely ruled out because of the limited FST values. Assignment tests confirm the overall picture that gene flow is limited across the river. We found that migration between samples from the same side of the river had a high probability indicating that orang‐utans used to move relatively freely between neighbouring areas. This strongly suggests that there is a need to maintain migration between isolated forest fragments. This could be done by restoring forest corridors alongside the river banks and between patches.
Microsatellites reveal regional population differentiation and isolation inLobaria pulmonaria, an epiphytic lichen
Authors: WALSER JEAN‐CLAUDE , HOLDEREGGER ROLF , GUGERLI FELIX , HOEBEE SUSAN EVA , SCHEIDEGGER CHRISTOPH 
Published: January 2005

AbstractMany lichen species produce both sexual and asexual propagules, but, aside from being minute, these diaspores lack special adaptations for long‐distance dispersal. So far, molecular studies have not directly addressed isolation and genetic differentiation of lichen populations, both being affected by gene flow, at a regional scale. We used six mycobiont‐specific microsatellite loci to investigate the population genetic structure of the epiphytic lichenLobaria pulmonariain two regions that strongly differed with respect to anthropogenic impact. In British Columbia,L. pulmonariagrows in continuous old‐growth forests, while its populations in the old cultural landscape of Switzerland are comparably small and fragmented. Populations from both British Columbia and Switzerland were genetically diverse at the loci. Geographically restricted alleles, low historical gene flow, and analyses of genetic distance (upgmatree) and of differentiation (amova) indicated that populations from Vancouver Island and from the Canadian mainland were separated from each other, except for one, geographically intermediate population. This differentiation was attributed to different glacial and postglacial histories of coastal and inland populations in British Columbia. In contrast to expectations, the three investigated Swiss populations were genetically neither isolated nor differentiated from each other despite the long‐lasting negative human impact on the lichen's range size in Central Europe. We propose that detailed studies integrating local landscape and regional scales are now needed to understand the processes of dispersal and gene flow in lichens.
Geographic and phylogenetic evidence for dispersed nuclear introgression in a daphniid with sexual propagules
Authors: TAYLOR DEREK J. , SPRENGER HEATHER L. , ISHIDA SEIJI 
Published: January 2005

AbstractThe role of among‐species gene flow in eukaryotic evolution remains controversial. Putative hybrid lineages are common in water fleas, but their ecological success is often associated with polyploidy and the production of asexual propagules. Advanced hybrid lineages with sexual propagules are expected to be geographically restricted because their successful dispersal is contingent on overcoming fertility complications, assimilation by parent taxa, and competition with parent taxa. Here we provide evidence that a diploid lineage ofDaphniahas been formed by introgression between distantly related species and attained a broad distribution (Nearctic) despite its requirement for sexual propagules. The evidence is based on geographical discordance, phylogenetic discordance, recombinant genotypes and additive genotypes of the nuclear internal transcribed spacer regions (ITS) and mitochondrial DNA. Additive genotypes also provided evidence of hybridization between introduced EuropeanDaphniaand North AmericanDaphnia. We argue that the unique biology of Holarctic lacustrine water fleas and the spatial separation of lineages during Pleistocene glaciation have promoted hybridization and its evolutionary consequences.
High specificity generally characterizes mycorrhizal association in rare lady's slipper orchids, genus Cypripedium
Authors: SHEFFERSON RICHARD P. , WEIß MICHAEL , KULL TIIU , TAYLOR D. LEE 
Published: January 2005

AbstractLady's slipper orchids (Cypripedium spp.) are rare terrestrial plants that grow throughout the temperate Northern Hemisphere. Like all orchids, they require mycorrhizal fungi for germination and seedling nutrition. The nutritional relationships of adult Cypripedium mycorrhizae are unclear; however, Cypripedium distribution may be limited by mycorrhizal specificity, whether this specificity occurs only during the seedling stage or carries on into adulthood. We attempted to identify the primary mycorrhizal symbionts for 100 Cypripedium plants, and successfully did so with two Cypripedium calceolus, 10 Cypripedium californicum, six Cypripedium candidum, 16 Cypripedium fasciculatum, two Cypripedium guttatum, 12 Cypripedium montanum, and 11 Cypripedium parviflorum plants from a total of 44 populations in Europe and North America, yielding fungal nuclear large subunit and mitochondrial large subunit sequence and RFLP (restriction fragment length polymorphism) data for 59 plants. Because orchid mycorrhizal fungi are typically observed without fruiting structures, we assessed fungal identity through direct PCR (polymerase chain reaction) amplification of fungal genes from mycorrhizally colonized root tissue. Phylogenetic analysis revealed that the great majority of Cypripedium mycorrhizal fungi are members of narrow clades within the fungal family Tulasnellaceae. Rarely occurring root endophytes include members of the Sebacinaceae, Ceratobasidiaceae, and the ascomycetous genus, Phialophora. C. californicum was the only orchid species with apparently low specificity, as it associated with tulasnelloid, ceratobasidioid, and sebacinoid fungi in roughly equal proportion. Our results add support to the growing literature showing that high specificity is not limited to nonphotosynthetic plants, but also occurs in photosynthetic ones.
Population structure of Columbia spotted frogs (Rana luteiventris) is strongly affected by the landscape
Authors: FUNK W. CHRIS , BLOUIN MICHAEL S. , CORN PAUL STEPHEN , MAXELL BRYCE A. , PILLIOD DAVID S. , AMISH STEPHEN , ALLENDORF FRED W. 
Published: January 2005

AbstractLandscape features such as mountains, rivers, and ecological gradients may strongly affect patterns of dispersal and gene flow among populations and thereby shape population dynamics and evolutionary trajectories. The landscape may have a particularly strong effect on patterns of dispersal and gene flow in amphibians because amphibians are thought to have poor dispersal abilities. We examined genetic variation at six microsatellite loci in Columbia spotted frogs (Rana luteiventris) from 28 breeding ponds in western Montana and Idaho, USA, in order to investigate the effects of landscape structure on patterns of gene flow. We were particularly interested in addressing three questions: (i) do ridges act as barriers to gene flow? (ii) is gene flow restricted between low and high elevation ponds? (iii) does a pond equal a ‘randomly mating population’ (a deme)? We found that mountain ridges and elevational differences were associated with increased genetic differentiation among sites, suggesting that gene flow is restricted by ridges and elevation in this species. We also found that populations of Columbia spotted frogs generally include more than a single pond except for very isolated ponds. There was also evidence for surprisingly high levels of gene flow among low elevation sites separated by large distances. Moreover, genetic variation within populations was strongly negatively correlated with elevation, suggesting effective population sizes are much smaller at high elevation than at low elevation. Our results show that landscape features have a profound effect on patterns of genetic variation in Columbia spotted frogs.
Geographical distance and physical barriers shape the genetic structure of Eurasian red squirrels (Sciurus vulgaris) in the Italian Alps
Authors: TRIZIO I. , CRESTANELLO B. , GALBUSERA P. , WAUTERS L. A. , TOSI G. , MATTHYSEN E. , HAUFFE H. C. 
Published: January 2005

AbstractRed squirrels (Sciurus vulgaris) are widely distributed throughout Eurasia, occurring in many types of coniferous and mixed‐deciduous forests. In fragmented landscapes, small and partly isolated populations with low immigration rates show reduced genetic diversity, but reforestation can increase gene flow and restore levels of genetic variation in a few decades. No studies have so far investigated the genetic structure of red squirrel in large, continuous forests. The Italian Alps are presently characterized by almost continuous, recently reconnected forest habitats, that were affected by deep landscape changes during last glaciations but remained mostly unchanged between 10 000 and 200 years bp, when forest cover was heavily reduced. In this study we analyse patterns of genetic variability of red squirrels in and between seven sites distributed over 250 km of Alpine habitat, using mitochondrial DNA (mtDNA) and microsatellites. We use isolation‐by‐distance (IBD) models to investigate the relative importance that past (Pleistocene glaciations) and recent (fragmentation, bottlenecks) events had on the present genetic situation. Both nuclear and mtDNA data indicate a significant differentiation among study sites and a significant correlation between genetic and geographical distance only over a large scale. No recent bottlenecks are recorded through microsatellites and demographic models strongly support equilibrium between gene flow and drift; however, mtDNA suggests that there may have been local demographic crashes, probably in correspondence with the 19th‐century forest fragmentation. These findings indicate that local landscape factors other than geographical distance per se, such as barriers of unsuitable habitat, affect gene flow and determine differentiation.