bluuebunny/crossref_metadata_2025_split huggingface dataset:
Microsatellite variation within and among North American lineages of Phragmites australis
Authors: Saltonstall K. 
Published: June 2003

AbstractOver the past century, the spread of the common reed (Phragmites australis) has had a dramatic impact on wetland communities across North America. Although native populations of Phragmites persist, introduced invasive populations have dominated many sites and it is not clear if the two types can interbreed. This study compares patterns of differentiation in 10 microsatellite loci among North American and European Phragmites individuals with results obtained from sequencing of noncoding chloroplast DNA. Three population lineages (native, introduced and Gulf Coast) were previously identified in North America from chloroplast DNA and similar structuring was found in the nuclear genome. Each lineage was distinguished by unique alleles and allele combinations and the introduced lineage was closely related to its hypothesized source population in Europe. Size homoplasy and diagnostic base substitutions distinguishing lineages were evident at several loci, further emphasizing that native, introduced and Gulf Coast North American Phragmites lineages are genetically distinct. Gene flow between lineages was low and invasive introduced populations do not represent a hybrid population type.
Historical biogeography of the catfish genus Hypostomus (Siluriformes: Loricariidae), with implications on the diversification of Neotropical ichthyofauna
Authors: Montoya‐Burgos J. I. 
Published: June 2003

AbstractTropical South America possesses the largest ichthyofauna of any continental region. To test whether palaeohydrological changes may have been the causes of such diversification, the ‘hydrogeological’ hypothesis, the phylogenetic relationships of 51 representatives of the catfish genus Hypostomus (Siluriformes: Loricariidae) were inferred using mitochondrial D‐loop haplotype sequences. Specimens were collected in all main tropical South American rivers systems east to the Andes. The major interrelationships found with the D‐loop data were confirmed with a subset of 21 species using complete internal transcribed spacer (ITS) region sequences. The phylogenetic analysis indicate that the genus Hypostomus can be divided into four monophyletic clades. The historical biogeographical analysis of each of these clades allows the identification of seven major cladogenetic events. Using calibrated D‐loop and ITS molecular clocks, date estimations were attributed to each of these cladogenetic events allowing a linkage between four of them with documented hydrogeological changes. Comparisons with published distribution patterns of unrelated fish groups indicate that several of the reconstructed and dated hydrogeological–cladogenetic events may have acted at a large scale on the diversification of Neotropical freshwater fish fauna during late Tertiary.
Parental tracking in the postfire wood decay ascomycete Daldinia loculata using highly variable nuclear gene loci
Authors: Guidot A. , Johannesson H. , Dahlberg A. , Stenlid J. 
Published: June 2003

AbstractThe origin of the male and female gametes involved in fertilization events within a local population of the postfire wood decay ascomycete Daldinia loculata was investigated by genotyping the mycelia growing in the wood and the sexual ascospores, using three highly variable nuclear gene loci. The study was conducted in a geographically isolated burned forest site in southern Sweden. An intensive sampling was performed by collecting stromata containing ascospores and wood samples containing mycelia. In total, from 32 mapped burned birches, cultures of 22 haploid genets from decayed wood and six ascospores from each of 19 stromata were isolated and analysed. In 80% of the investigated burned branches, only one genet was found. From the analysis of the ascospore genotypes, we detected 30 fertilization events and 60% of them were the result of mating between conidia (clonal propagules) acting as male gametes and the genets in the branches representing the female gametes. The male parents producing the conidia were detected within the same local population as the female parents in 27% of the fertilization events and originated either from the same branch or from different trees located at 0.5–36 m away from the female parents. In 33% of the fertilization events, conidia originated from three male parents that were not found within the local population sampled. These parents could be anywhere inside or outside the sampled area. For the remaining fertilization events, we could not rule out the ascospores or the conidia as fertilizing propagules. No strong evidence for fertilization by recombinant propagules (ascospores) was detected in this study. The pyrophilous insect species associated with conidia of D. loculata are suggested to be essential vectors for the realization of the sexual cycle of this fungal species. By feeding on the conidia and flying between nearby trees inhabiting wood decay mycelia, these insects allow the transfer of conidia and therefore the opposite mating types to meet within a localized burned forest site.
A new approach to detecting mixed families
Authors: Vines Timothy H. , Barton Nicholas H. 
Published: June 2003

AbstractThere are several analyses in evolutionary ecology which assume that a family of offspring has come from only two parents. Here, we present a simple test for detecting when a batch involves two or more subfamilies. It is based on the fact that the mixing of families generates associations amongst unlinked marker loci. We also present simulations illustrating the power of our method for varying numbers of loci, alleles per locus and genotyped individuals.
From connectivity to isolation: genetic consequences of population fragmentation in capercaillie across Europe
Authors: Segelbacher G. , Höglund J. , Storch I. 
Published: June 2003

AbstractThe capercaillie inhabits a continuous range in large parts of the Palearctic boreal forest, but is patchily distributed in temperate Europe. An ongoing population decline, largely related to human land use changes, has been most pronounced in central and western Europe, where some local populations have become extinct. In this study, we document the genetic differentiation of capercaillie populations at different stages along a gradient of spatial structuring from high connectivity (continuous range in the boreal forest) to a metapopulation systems (Alps) and recent (central Europe) and historic (Pyrenees) isolation. Four hundred and sixty individuals from 14 sample sites were genotyped at 10 polymorphic microsatellite loci to assess genetic structure and variation of capercaillie populations across its European range. As expected, differentiation was least pronounced within the continuous range in the boreal forest. Within the metapopulation system of the Alps, differentiation was less than among the isolated populations of central Europe (Black Forest, Fichtelgebirge, Thuringia, Vosges). In the long‐isolated population of the Pyrenees, and the recently isolated populations of central Europe, genetic diversity was significantly reduced compared with the Alps and boreal forest. Our results agree with the concept of a gradual increase in genetic differentiation from connectivity to isolation, and from recent to historic isolation. Anthropogenic habitat deterioration and fragmentation thus not only leads to range contractions and extinctions, but may also have significant genetic and evolutionary consequences for surviving populations. To maintain high levels of genetic variation in species in fragmented habitats, conservation should aim at securing connectivity between spatially distinct populations.
Neighbourhood‐scale diversity, composition and root crowding do not alter competition during drought in a native grassland
Authors: Cahill James F. 
Published: June 2003

AbstractThe diversity‐invasion resistance theory argues that increased diversity results in increased competitive suppression of establishing plants. Although there is support for the pattern of decreased invasion with increased diversity, empirical demonstrations of increased competition are limited. An experiment was conducted during a severe drought in a native grassland community. The drought resulted in minimal shading among neighbours, and in contrast to prior studies, competition here was exclusively belowground. Neither diversity nor community composition influenced root crowding or competition. It appears that when competition is belowground, it is independent of diversity, likely because of fundamental differences in the mechanisms of above‐ and belowground competition. This suggests that even at the neighbourhood scale, there is no inherently negative relationship between competition and diversity, and lends support to alternative theories which suggest factors of than diversity may more strongly influence community invasibility.
The bacterial ecology of a plague‐like disease affecting the Caribbean coral Montastrea annularis
Authors: Pantos Olga , Cooney Rory P. , Le Tissier Martin D. A. , Barer Michael R. , O'Donnell Anthony G. , Bythell John C. 
Published: June 2003

SummaryThe bacterial communities associated with the Caribbean coral Montastrea annularis showing tissue lesions indicative of a White Plague (WP)‐like disease were investigated. Two molecular screening techniques using bacterial 16S rDNA genes were used and demonstrated distinct differences between the bacterial communities of diseased and non‐diseased coral tissues, and also in relation to the proximity of tissue lesions on diseased corals. Differences between non‐diseased corals and the apparently healthy tissues remote from the tissue lesion in affected corals indicates a ‘whole coral’ response to a relatively small area of infection with a perturbation in the normal microbial flora occurring prior to the onset of visible signs of disease. These whole organism changes in the microbial flora may serve as a bioindicator of environmental stress and disease. There were striking similarities between the 16S rDNA sequence composition associated with the WP‐like disease studied here and that previously reported in association with black band disease (BBD) in coral. Similarities included the presence of a potential pathogen, an α‐proteobacterium identified as the causal agent of juvenile oyster disease (JOD). The WP‐like disease studied here is apparently different to WP Type ii because the bacterial species previously identified as the causal agent of WP Type ii was not detected, although the symptoms of the two diseases are similar.
Species composition and antimicrobial resistance genes of Enterococcus spp., isolated from integrated and traditional fish farms in Thailand
Authors: Petersen Andreas , Dalsgaard Anders 
Published: June 2003

SummaryIntegrated fish farming uses the manure from animal husbandry as fertilisers in the fish ponds. A total of 410 enterococcal isolates, from integrated and traditional fish farms in Thailand, were collected to assess whether the input of manure from chickens receiving feed containing growth promoters and antimicrobial treatments influenced the species composition and the bacterial antimicrobial resistance in the fish pond environment. Enterococcus faecium and E. faecalis were the predominate species isolated from the integrated farms, whereas E. casseliflavus and E. mundtii isolates were most prevalent in traditional farms. Enterococcus faecalis and E. faecium demonstrated the highest prevalence of resistance, whereas E. mundtii isolates were susceptible to all antimicrobials tested. All the enterococci species isolated from the integrated farms, generally demonstrated higher resistance phenotypes to the tested antimicrobials compared with the same species from traditional farms. The erm(B) and tet(M) genes, associated with resistance to erythromycin and tetracycline, respectively, were found in 87% of the erythromycin‐resistant and 95% of the oxytetracycline‐resistant enterococci isolates respectively. These results suggest that the species composition and antimicrobial resistance of enterococci in tropical aquatic environments are influenced by faecal and antimicrobial pollution.
The chemokine receptor CCR5 is not a necessary inflammatory mediator in kainic acid‐induced hippocampal injury: evidence for a compensatory effect by increased CCR2 and CCR3
Authors: Chen Zhiguo , Yu Shuo , Bakhiet Moiz , Winblad Bengt , Zhu Jie 
Published: June 2003

AbstractChemokines and their receptors have been strongly implicated in the inflammatory process. However, their roles in excitotoxic brain injury are largely unknown. In this study we used C‐C chemokine receptor 5 (CCR5) knockout (KO) mice to investigate the role of CCR5 in neurodegeneration induced by intranasal administration of the excitotoxin kainic acid (KA). Although KA treatment resulted in an increased CCR5 mRNA level in the hippocampi of wild‐type mice, a CCR5 deficiency in KO mice did not affect either the clinical and pathological changes in vivo or the neuronal susceptibilities to KA insult in vitro. KA treatment stimulated mRNA expression of the monocyte chemoattractant protein‐2 (MCP‐2) in both the wild‐type and KO mice. KA treatment did not affect mRNA levels for the macrophage inflammatory protein‐1α (MIP‐1α) or the regulated upon activation normal T cells expressed and secreted protein (RANTES) in either wild‐type or CCR5 KO mice. CCR2 mRNA expression was undetectable in the hippocampi of wild‐type mice regardless of KA treatment. In contrast, CCR5 KO mice showed CCR2 mRNA expression that was remarkably increased after KA treatment. KA treatment did not affect CCR3 mRNA expression in the wild‐type mice, whereas KO mice showed both a higher basal level of CCR3 mRNA expression as well as a strong upregulation following KA treatment. These results indicate that CCR5 is not a necessary inflammatory mediator in KA induced neurodegeneration. The roles of CCR5 in excitotoxic injury in CCR5 deficient mice are compensated by increased CCR2 and CCR3 expression, which share the common MCP‐2 ligand with CCR5.
l‐DOPA supply to the neuro retina activates dopaminergic communication at the early stages of embryonic development
Authors: Kubrusly Regina C. C. , Guimarães Marília Zaluar P. , Vieira Ana Paula B. , Hokoç Jan N. , Casarini Dulce E. , De Mello Maria C. F. , De Mello Fernando G. 
Published: June 2003

AbstractDOPA decarboxylase (DDC; aromatic‐l‐amino acid decarboxylase; EC 4.1.1.28) is absent in retinas from 6‐day‐old chicken embryos (E6) but is expressed in retina of E8 embryos, in the presumptive outer plexiform layer. Thereafter, DDC appears in cell bodies of presumptive amacrine cells. The dopamine (DA) content of E9/10 and E15/16 retinas, pre‐incubated with l‐DOPA for 1 h, increased 250‐ and 600‐fold, respectively, showing that DDC is active since early in development. Intercellular communication, measured by endogenous cyclic AMP accumulation, was observed when retinas from E9/10 to E15/16 were pre‐incubated for 1 h with 1 mm l‐DOPA, washed and followed by incubation in the presence of 0.5 mm 3‐isobutyl‐1‐methylxanthine, a phosphodiesterase inhibitor. Cyclic AMP accumulation was prevented when pre‐incubation with l‐DOPA was carried out in the presence of carbidopa. Moreover, the accumulation of cyclic AMP was inhibited by SCH 23390 (2 µm). The incubation of retinas in medium previously conditioned by retina‐pigmented epithelium (RPE) also increased its cyclic AMP content with the characteristics described for l‐DOPA. Our results show that dopaminergic communication takes place in the embryonic retina, before tyrosine hydroxylase expression, provided l‐DOPA is supplied to the tissue. It also shows that RPE is a potential source of l‐DOPA early in development.
Regulation of ania‐6 splice variants by distinct signaling pathways in striatal neurons
Authors: Sgambato Véronique , Minassian Raia , Nairn Angus C. , Hyman Steven E. 
Published: June 2003

AbstractThe striatum is a brain region involved in motor control and in diverse forms of implicit memory. It is also involved in the pathogenesis of many significant human disorders, including drug addiction, that are thought to involve adaptive changes in gene expression. We have previously shown that the cyclin L, ania‐6, is expressed as at least two splice forms, which are differentially regulated in striatal neurons by different neurotransmitters. Here, we report that ania‐6 transcription is mostly regulated via cAMP response element binding protein (CREB), but that signaling pathways that converge on CREB at the transcriptional level produce different effects on splicing and neuronal gene expression. Glutamate induced a long ania‐6 mRNA that encodes a truncated form of the cyclin. This effect depended on the activation of NMDA receptors but was independent of both calcium/calmodulin‐dependent protein kinases (CaMK) and extracellular regulated kinase (ERK). Forskolin or brain‐derived neurotropic factor (BDNF) induced a short ania‐6 mRNA, that encodes the full‐length cyclin, and this induction depended on ERK. However, KCl‐mediated induction of ania‐6 short mRNA, which required activation of L‐type calcium channels, was independent of ERK but depended on CaMK. These data suggest that different neuronal signals can differentially regulate splicing and that different intracellular pathways can be recruited to yield a given splice variant.
Validity and repeatability of a simple index derived from the short physical activity questionnaire used in the European Prospective Investigation into Cancer and Nutrition (EPIC) study
Authors: Wareham Nicholas J , Jakes Rupert W , Rennie Kirsten L , Schuit Jantine , Mitchell Jo , Hennings Susie , Day Nicholas E 
Published: June 2003

AbstractObjective:To assess the validity and repeatability of a simple index designed to rank participants according to their energy expenditure estimated by self-report, by comparison with objectively measured energy expenditure assessed by heart-rate monitoring with individual calibration.Design:Energy expenditure was assessed over one year by four separate episodes of 4-day heart-rate monitoring, a method previously validated against whole-body calorimetry and doubly labelled water. Cardio-respiratory fitness was assessed by four repeated measures of sub-maximum oxygen uptake. At the end of the 12-month period, participants completed a physical activity questionnaire that assessed past-year activity. A simple four-level physical activity index was derived by combining occupational physical activity together with time participating in cycling and other physical exercise (such as keep fit, aerobics, swimming and jogging).Subjects:One hundred and seventy-three randomly selected men and women aged 40 to 65 years.Results:The repeatability of the physical activity index was high (weighted kappa = 0.6, P < 0.0001). There were positive associations between the physical activity index from the questionnaire and the objective measures of the ratio of daytime energy expenditure to resting metabolic rate (P = 0.003) and cardio-respiratory fitness (P = 0.001). As an indirect test of validity, there was a positive association between the physical activity index and the ratio of energy intake, assessed by 7-day food diaries, to predicted basal metabolic rate.Conclusions:The summary index of physical activity derived from the questions used in the European Prospective Investigation into Cancer and Nutrition (EPIC) study suggest it is useful for ranking participants in terms of their physical activity in large epidemiological studies. The index is simple and easy to comprehend, which may make it suitable for situations that require a concise, global index of activity.
The association between red and processed meat consumption and iron intakes and status among British adults
Authors: Gibson Sigrid , Ashwell Margaret 
Published: June 2003

AbstractObjective:To examine the association between consumption of red and processed meat (RPM) and iron intakes and status in adults.Design:Further analysis of the Dietary and Nutritional Survey of British Adults, a cross-sectional study of 2197 adults aged 16–64 years carried out in 1986/7.Subjects and methods:Adults (836 men and 838 women) with serum ferritin measurements, who were not taking iron supplements, were classified into four groups according to RPM consumption (from 7-day weighed records). Iron absorbed was estimated from equations based on haem and non-haem iron and the influence of iron stores.Results:Women who ate least meat (<90gday-1) had three times the risk of a low iron intake (below the Lower Reference Nutrient Intake) compared with high consumers of RPM (>140gday-1). Men who ate no RPM also had a higher risk of low iron intake. Using an estimate of minimal values for iron losses, there was a twofold difference in the potential risk of negative iron balance between women non-RPM consumers and high RPM consumers. Status measurements indicated that, among women, anaemia was least prevalent (6%) among high consumers compared with 12–14% among average RPM consumers. Inverse trends were also observed for serum ferritin in both sexes.Conclusions:Low consumption of RPM has implications for iron intakes and iron status in men and women, since the risk of negative iron balance and its consequences are increased. Dietary messages must consider these implications and provide appropriate advice.
Adaptation of international nutrition databases and data-entry system tools to a specific population
Authors: Shai Iris , Vardi Hillel , Shahar Danit R , Azrad Ayelet B , Fraser Drora 
Published: June 2003

AbstractObjective:To develop a nutritional dietary intake database based on available reliable international nutritional databases adapted to the local needs of a specific population.Design:The Negev Nutritional Study (NNS) is a survey of a random sample of the Negev population regarding their dietary intake using 24-hour dietary recalls. A nutritional database for the Israeli population was developed based on adaptation and modification of the US Department of Agriculture's database. A data-entry system was developed based on the logic of the US Food Information Analysis System. The system was designed as bilingual (English and Hebrew). Local foods and recipes were collected during the NNS, which included 1465 24-hour diet interviews.Results:During the course of the NNS, 383 basic Israeli recipes were constructed. In total 1362 Israeli products were added to the database, and each was given a code, specific gravity and portion size. Most of the added products were cereals and grains and dairy products. The added recipes were collected from the interviewees in the NNS and from the most popular cookbooks.Conclusions:This paper describes the process undertaken to develop an Israeli food composition database as well as the data-entry system. This knowledge may aid other research groups in developing a computerised, nation-specific nutritional database and data-entry system adapted to their own specific local needs.