bluuebunny/crossref_metadata_2025_split huggingface dataset:
A method for double‐stranded RNA‐mediated transient gene silencing in Phytophthora infestans
Authors: WHISSON STEPHEN C. , AVROVA ANNA O. , VAN WEST PIETER , JONES JOHN T. 
Published: March 2005

SUMMARYGene silencing, triggered by double‐stranded RNA (dsRNA), has proved to be a valuable tool for determining and confirming the function of genes in many organisms. For Phytophthora infestans, the cause of late blight on potato and tomato, gene silencing strategies have relied on stable transformation followed by spontaneous silencing of both the endogenous gene and the transgene. Here we describe the first application of transient gene silencing in P. infestans, by delivering in vitro synthesized dsRNA into protoplasts to trigger silencing. A marker gene, gfp, and two P. infestans genes, inf1 and cdc14, both of which have been silenced previously, were selected to test this strategy. Green fluorescent protein (GFP) fluorescence was reduced in regenerating protoplasts up to 4 days after exposure to gfp dsRNA. A secondary reduction in expression of all genes tested was not fully activated until 12–17 days after introduction of the respective homologous dsRNAs. At this time after exposure to dsRNA, reduced GFP fluorescence in gfp dsRNA‐treated lines, and reduced INF1 production in inf1 dsRNA‐treated lines, was observed. Introduction of dsRNA for the stage‐specific gene, cdc14, yielded the expected phenotype of reduced numbers of sporangia when cdc14 expression was significantly reduced compared with control lines. Silencing was shown to be sequence‐specific, because analysis of inf1 expression in gfp‐silenced lines yielded wild‐type levels of gene expression. This report shows that transient gene silencing can be used to generate detectable phenotypes in P. infestans and should provide a high‐throughput tool for P. infestans functional genomics.
Terminal deoxynucleotidyl transferase‐positive cells in trephine biopsies following bone marrow or peripheral stem cell transplantation reflect vigorous B‐cell generation
Authors: Wolf E , Harms H , Winkler J , Reulbach U , Kirchner T , Niedobitek G , Baumann I 
Published: March 2005

Aims : Bone marrow is the major site of B‐cell generation in humans. While in early childhood a high number of B‐cell precursors is found in the bone marrow, only very few such cells are usually detectable in adult bone marrow. To assess the number of immature B cells present after haematopoietic cell transplantation the number of terminal deoxynucleotidyl transferase (TdT)‐positive cells in regenerating bone marrow of adult patients was analysed.Methods and results : Bone marrow biopsy specimens were analysed from patients after allogeneic bone marrow transplantation (BMT; n = 14) or stem cell transplantation (SCT; n = 25) and autologous BMT (n = 9). Specimens from 11 untransplanted adult patients and 11 infants were also studied, as negative and positive controls, respectively. Immunohistochemistry was performed on paraffin‐embedded bone marrow biopsy sections using TdT as a marker of lymphoid progenitors. Immunoreactivity for CD79a, CD20 and CD10 was used to confirm their B‐cell origin. Using computer‐assisted automated image analysis we quantitatively assessed the TdT+ cells present. We found a significant increase in the numbers of B‐cell precursors in the bone marrow after allogeneic and autologous BMT/SCT compared with adult controls (P = 0.022). To analyse this in detail, we followed some patients after allogeneic BMT/SCT for up to 1445 days, when a marked B‐cell increase was still detectable. However, the median number of TdT+ B cells after BMT/SCT was significantly lower than the number of equivalent B cells in infantile bone marrow biopsy specimens (P < 0.001).Conclusions : Bone marrow of adult patients after BMT/SCT is capable of initiating vigorous precursor B‐cell generation, which is not seen in untransplanted adults. However, the increase of immature B cells was variable in our study. Only in two young adult patients did it reach the magnitude of B‐cell generation seen in infantile bone marrow where immunocompetent B cells are produced normally. A marked increase in number of immature B cells post‐transplant may mimic B‐cell acute lymphoblastic leukaemia (B‐ALL). This is a potential problem in patients transplanted for B‐ALL itself. Since reactive and neoplastic B‐cell precursors share the same immunophenotype in paraffin‐embedded tissue, additional tools, particularly molecular techniques, may have to be employed to establish the correct diagnosis.
Morphometric analysis of primary graft non‐function in liver transplantation
Authors: Vertemati M , Sabatella G , Minola E , Gambacorta M , Goffredi M , Vizzotto L 
Published: March 2005

Aims : Primary graft non‐function (PNF) is a life‐threatening condition that is thought to be the consequence of microcirculation injury. The aim of the present study was to assess, with a computerized morphometric model, the morphological changes at reperfusion in liver biopsy specimens from patients who developed PNF after liver transplantation.Methods and results : Biopsy specimens were obtained at maximum ischaemia and at the end of reperfusion. Morphology included many stereological parameters, such as volumes of all parenchymal components, surface density, size distribution and mean diameter of hepatocytes. Other variables examined were intensive care unit stay, degree of steatosis, serum liver function tests and ischaemic time. In the postoperative period, the PNF group showed elevated serum levels of alanine transferase, decreased daily rate of bile production and prothrombin activity. Blood lactates were significantly higher in the PNF group than in a control group. When comparing groups, the volumetric parameters related to hepatocytes and sinusoids and the surface densities of the hepatic cells showed an inverse relationship. At the end of reperfusion, in PNF group the volume fraction of hepatocyte cytoplasm was decreased; in contrast, the volume fraction of sinusoidal lumen was markedly increased. The cell profiles showed the same inverse trend: the surface density of the parenchymal border of hepatocytes was decreased in PNF when compared with the control group, while the surface density of the vascular border was increased. In the PNF group, the surface density of the sinusoidal bed was directly correlated with alanine transferase, daily rate of bile production, prothrombin activity and cold ischaemic time.Conclusions : The alterations in hepatic architecture, as demonstrated by morphometric analysis in liver transplant recipients that developed PNF, provide additional information that may represent useful viability markers of the graft to complement conventional histological analysis.
Beating the barriers: recruitment of people with intellectual disability to participate in research
Authors: Lennox N. , Taylor M. , Rey‐Conde T. , Bain C. , Purdie D. M. , Boyle F. 
Published: March 2005

AbstractBackground  The health status of people with intellectual disability (ID) is poor, yet very little research has been done on their health needs. There are several barriers to performing this research. The aim of our research was to examine the significant barriers encountered in recruiting adults with ID to participate in research.Methods  Our project was a randomized controlled trial aiming to improve health advocacy of people with ID. We approached many organizations to recruit participants and kept records of our results. Recruitment was very low for the first 4 months. Then we adopted two new recruitment strategies – in‐service telephone recruitment and meetings with prospective participants. We then monitored the subsequent recruitment rates. We also questioned participants about the difficulties they encountered when considering recruitment.Results  Initial recruitment of participants yielded less than one‐third of the expected number. Additional strategies implemented were partially successful. Significant barriers to recruitment included several sectoral issues and the challenges arising from the research process.Conclusions  While this population is a difficult one to reach for research, attempts to do so should not be abandoned, because the potential health benefits for this underserved group far outweigh the recruitment barriers experienced.
Barrier to gene flow between two ecologically divergentPopulusspecies,P. alba(white poplar) andP. tremula(European aspen): the role of ecology and life history in gene introgression
Authors: LEXER C. , FAY M. F. , JOSEPH J. A. , NICA M.‐S. , HEINZE B. 
Published: March 2005

AbstractThe renewed interest in the use of hybrid zones for studying speciation calls for the identification and study of hybrid zones across a wide range of organisms, especially in long‐lived taxa for which it is often difficult to generate interpopulation variation through controlled crosses. Here, we report on the extent and direction of introgression between two members of the ‘model tree’ genusPopulus:Populus alba(white poplar) andPopulus tremula(European aspen), across a large zone of sympatry located in the Danube valley. We genotyped 93 hybrid morphotypes and samples from four parental reference populations from within and outside the zone of sympatry for a genome‐wide set of 20 nuclear microsatellites and eight plastid DNA restriction site polymorphisms. Our results indicate that introgression occurs preferentially fromP. tremulatoP. albaviaP. tremulapollen. This unidirectional pattern is facilitated by high levels of pollen vs. seed dispersal inP. tremula(pollen/seed flow = 23.9) and by great ecological opportunity in the lowland floodplain forest in proximity toP. albaseed parents, which maintains gene flow in the direction ofP. albadespite smaller effective population sizes (Ne) in this species (P. alba Nec.500–550;P. tremula Nec.550–700). Our results indicate that hybrid zones will be valuable tools for studying the genetic architecture of the barrier to gene flow between these two ecologically divergentPopulusspecies.
Ancient and recent evolutionary history of the bruchid beetle, Acanthoscelides obtectus Say, a cosmopolitan pest of beans
Authors: ALVAREZ NADIR , MCKEY DOYLE , HOSSAERT‐MCKEY MARTINE , BORN CÉLINE , MERCIER LÉNY , BENREY BETTY 
Published: March 2005

Abstract Acanthoscelides obtectus Say is a bruchid species of Neotropical origin, and is specialized on beans of the Phaseolus vulgaris L. group. Since the domestication and diffusion of beans, A. obtectus has become cosmopolitan through human‐mediated migrations and is now a major pest in bean granaries. Using phylogeographic methods applied to mitochondrial DNA (mtDNA) and nuclear microsatellite molecular markers, we show that the origin of this species is probably further south than Mesoamerica, as commonly thought. Our results also indicate that A. obtectus and its Mesoamerican sister species Acanthoscelides obvelatus, two morphologically close species differing principally in voltinism, speciated in allopatry: A. obtectus (multivoltine) arising in Andean America and A. obvelatus (univoltine) in Mesoamerica. In contrast to Mesoamerica where beans fruit once yearly, wild beans in Andean America fruit year‐round, especially in regions showing little or no seasonality. In such habitats where resources are continuously present, multivoltinism is adaptive. According to existing hypotheses, multivoltinism in A. obtectus is a new adaptation that evolved after bean domestication. Our data suggest the alternative hypothesis that multivoltinism is an older trait, adapted to exploit the year‐round fruiting of wild beans in relatively aseasonal habitats, and allowed A. obtectus to become a pest in bean granaries. This trait also permitted this species to disperse through human‐mediated migrations associated with diffusion of domesticated beans. We also show that diversity of Old World A. obtectus populations can be quite well explained by a single colonization event about 500 bp. Human‐mediated migrations appear not to be rare, as our results indicate a second more recent migration event from Andean America to Mexico.
Phloem long‐distance trafficking of GIBBERELLIC ACID‐INSENSITIVE RNA regulates leaf development
Authors: Haywood Valerie , Yu Tien‐Shin , Huang Nien‐Chen , Lucas William J. 
Published: March 2005

SummaryThe phloem translocation stream contains a population of RNA molecules, suggesting plants use RNA to integrate developmental processes, at the whole‐plant level. In the present study, we analyzed the role of long‐distance trafficking in the delivery of transcripts from two members of the GRAS family, namely CmGAIP and GAI. These two homologs were chosen because of their involvement as transcriptional regulators in GA signaling. A combination of pumpkin, tomato and Arabidopsis was employed to examine the processes involved in long‐distance delivery, to sink tissues, of RNA for engineered dominant gain‐of‐function pumpkin (Cmgaip) and Arabidopsis (ΔDELLA‐gai) genes. Our studies demonstrate that gai RNA entry into functional sieve elements occurs via a selective process. Both engineered mutant gai transcripts were able to exit the scion phloem and traffic cell to cell into the shoot apex. Delivery of Cmgaip and ΔDELLA‐gai RNA mediated highly reproducible changes in leaf phenotype in transgenic tomato lines grown under greenhouse conditions. Phenotypic analysis indicated that tomato leaflet morphology was influenced quite late in development. In addition, tissue sink strength did not appear to dictate gai RNA delivery, suggesting complexity in the process underlying macromolecular trafficking. These results establish that the molecular properties of the Cmgaip and ΔDELLA‐gai transcripts are compatible with the tomato cell‐to‐cell and long‐distance macromolecular trafficking systems. An important conclusion, based on our work, is that control over GAI RNA delivery, via the phloem, may be regulated by sequence motifs conserved between plant families. We propose that RNA delivery via the phloem allows for flexibility in fine tuning of developmental programs to ensure newly developing leaves are optimized for performance under the prevailing environmental conditions.
shk1‐D, a dwarf Arabidopsis mutant caused by activation of the CYP72C1 gene, has altered brassinosteroid levels
Authors: Takahashi Naoki , Nakazawa Miki , Shibata Kyomi , Yokota Takao , Ishikawa Akie , Suzuki Kumiko , Kawashima Mika , Ichikawa Takanari , Shimada Hiroaki , Matsui Minami 
Published: March 2005

SummaryBrassinosteroids (BRs) are plant steroidal hormones that regulate plant growth and development. An Arabidopsis dwarf mutant, shrink1‐D (shk1‐D), was isolated and the phenotype was shown to be caused by activation of the CYP72C1 gene. CYP72C1 is a member of the cytochrome P450 monooxygenase gene family similar to BAS1/CYP734A1 that regulates BR inactivation. shk1‐D has short hypocotyls in both light and dark, and short petioles and siliques. The seeds are also shortened along the longitudinal axis indicating CYP72C1 controls cell elongation. The expression of CPD, TCH4 and BAS1 were altered in CYP72C1 overexpression transgenic lines and endogenous levels of castasterone, 6‐deoxocastasterone and 6‐deoxotyphasterol were also altered. Unlike BAS1/CYP734A1 the expression of CYP72C1 was not changed by application of exogenous brassinolide. We propose that CYP72C1 controls BR homeostasis by modulating the concentration of BRs.
Dendritic Cell Differentiation and Maturation in Embryonic Rat Liver: Immunohistochemistry and Electron Microscopy with Reference to Dendritic Cell Contacts
Authors: El‐Nefiawy N. , Abdel‐Hakim K. , Kanayama N. , Terao T. 
Published: March 2005

SummaryThis study investigated the dendritic cell (DC) differentiation in embryonic rat liver utilizing in situ ultrastructural characterization and immunohistochemistry. The study revealed the existence of DCs early in hepatic ontogeny with positive immune staining to the OX‐62 monoclonal antibody. DCs existed in three differentiating stages: immature, mature and transitional forms in between. At 14 and 16 days of gestation, immature and transitional forms of DCs dominated. Mature cells increased significantly in number through late gestational days (18 days onwards). DCs (particularly mature and moderate mature forms) revealed signs of active phagocytosis manifested by the existence of cytoplasmic phagosomes and heterophagosomes. At 18 days of gestation as well as newborn liver mature DCs displayed two distinct morphological phenotypes according to the degree of development of either the smooth endoplasmic reticulum or the lysosomal compartment. Mature DCs delineated close appositions to other DCs, hepatocytes, and clustering with lymphocytes especially through their cellular processes. The features of phagocytosis and DC–T‐cell contacts may signify a role of DCs in immune surveillance in the embryonic liver.
The Arterial Vascularization of Septum Interventriculare in Donkeys (Equus asinus L.)
Authors: Ozgel O. , Dursun N. 
Published: March 2005

SummaryIn this study, arteries that supply the septum interventriculare in donkeys, their course and variations, if present, were defined. Six hearts belonging to donkeys of varying age and sex constituted the material of the study. In order to expose the arteries, latex coloured with Rotring ink was injected into a. coronaria sinistra and a. coronaria dextra and dissection was performed. The arterial vascularization of the heart in donkeys is supplied by a. coronaria sinistra and a. coronoria dextra, which have their origin at the aorta. A. coronaria sinistra gives off two branches: one is ramus interventricularis paraconalis, which extends into the sulcus interventricularis paraconalis and the other is ramus circumflexus sinister, which lies within the sulcus coronarius. A. coronaria dextra is formed by the union of ramus interventricularis subsinuosus and ramus circumflexus dexter. Septum interventriculare is supplied by rr. septales, which originate from ramus interventricularis paraconalis, a branch of a. coronaria sinistra, as well as rami septales which have their origin in ramus interventricularis subsinuosus, a branch of a. coronaria dextra.
Impact of Growth Factors on In Vitro Development of Caprine Oocytes at Pre‐antral Stage
Authors: Zhou HM , Zhang Y 
Published: March 2005

ContentsThe objective of this study was to examine the effect of various growth factors such as the epidermal growth factor (EGF) and insulin‐like growth factor‐I (IGF‐I) either individually or in association, in the presence of follicle‐stimulating hormone (FSH) on the in vitro growth and viability of caprine oocytes at pre‐antral stage. Pre‐antral follicles were disassociated enzymatically and mechanically from pre‐pubertal caprine ovaries after the animals were anaesthetically ovariectomized. Caprine pre‐antral follicles in group 1, 2, 3 and 4 were cultured in growth culture medium, growth culture medium + EGF, growth culture medium + IGF‐I and growth culture medium + IGF‐I + EGF, respectively, for 9 days. The results indicated that EGF (50 mg/l) increased the survival rate of oocytes, but decreased the growth rate of oocytes; IGF‐I (100 mg/l) effectively maintained the survival of oocytes and stimulated their growth; IGF‐I (100 mg/l) and EGF (50 mg/l) in combination produced a higher effect on both the survival and the growth rate of oocytes than IGF‐I or EGF alone. Conclusively, the growth factors can effectively maintain the survival of caprine oocytes from pre‐antral follicles and regulate their growth in culture. EGF and IGF‐I in association could synergically meliorate the culture system of caprine pre‐antral follicles.
Macronutrient intake, physical activity, serum lipids and increased body weight in primary schoolchildren in Istanbul
Authors: Manios Yannis , Kolotourou Maria , Moschonis George , Sur Haydar , Keskin Yasar , Kocaoglu Bike , Hayran Osman 
Published: March 2005

Abstract
Background
: The aim of this cross‐sectional study was to record the prevalence of underweight, overweight and obesity in primary school children living in Istanbul and to examine the relationship between increased body weight and certain cardiovascular disease (CVD) risk factors.
Methods
: A total of 510 randomly selected children aged 12 and 13 years of age (257 boys, 253 girls) were examined. Information regarding anthropometrical indices, energy and macronutrient intake, physical activity, physical fitness and lipid profile were collected. Classification of children in overweight and obese subgroups was based on the cut‐off points proposed by Cole et al.1
Results
: The prevalence of underweight, overweight and obesity was found to be 15.3%, 10.6% and 1.6%, respectively. Both overweight boys and girls were found to have lower physical fitness compared to their normal‐weight counterparts, but no difference was observed for energy and macronutrient intake. Overweight boys were found to have higher total cholesterol (P < 0.001), low‐density lipoprotein cholesterol (P < 0.01), triglycerides (P < 0.01) and total cholesterol/high‐density lipoprotein cholesterol (HDL‐C) ratio (P < 0.05) compared to their normal‐weight counterparts, while overweight girls were found to have lower HDL‐C (P < 0.05) compared to their normal‐weight peers.
Conclusions
: Underweight and overweight coexisted in the current population. Increased body weight was accompanied by unfavorable lipid profiles and lower fitness levels. Consequently, there is an emergent need for early identification and understanding of behavioral and physiological variables related to obesity and CVD, so that appropriate interventions can be targeted to children who are at risk for adult onset of these diseases.
Hopelessness and suicidal ideation among adolescents in two cultures
Authors: Stewart Sunita Mahtani , Kennard Betsy D. , Lee Peter W.H. , Mayes Taryn , Hughes Carroll , Emslie Graham 
Published: March 2005

Background:  This study examines the cross‐sectional and longitudinal associations among cognitive variables, depressive symptoms and suicidal ideation in Hong Kong Chinese and Caucasian American adolescents.Methods:  Community adolescents (n = 2,044) ages 14–18 years from Hong Kong and the United States provided information regarding their suicidal ideation, depressive symptoms, and cognitions (self‐efficacy, cognitive errors and hopelessness), at two surveys, six months apart.Results:  Self‐efficacy was a weak unique predictor of suicidal ideation in both cultures. Hopelessness was the strongest of cognitive variables in concurrent associations with suicidal ideation in bivariate and multivariate models, in both cultures, and in both boys and girls. Hopelessness continued to offer unique prediction when depressive symptoms were controlled, both concurrently and prospectively.Conclusions:  Our results support hopelessness theories of suicidal ideation and behavior in Hong Kong, and extend the cognitive theory of suicidality to a modernized Asian culture.