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22.
Sylvain Ursenbacher Caren Alvarez Georg F. J. Armbruster Bruno Baur 《Conservation Genetics》2010,11(4):1265-1271
Understanding patterns of genetic structure is fundamental for developing successful management programmes for isolated populations
of threatened species. Trochulus caelatus is a small terrestrial snail endemic to calcareous rock cliffs in the Northwestern Swiss Jura Mountains. Eight microsatellite
loci were used to assess the effect of habitat isolation on genetic population structure and gene flow among nine populations
occurring on distinct cliffs. We found a high genetic differentiation among populations (mean F
ST = 0.254) indicating that the populations are strongly isolated. Both allelic richness and effective population size were
positively correlated with the size of the cliffs. Our findings support the hypothesis that T. caelatus survived on ice-free cliffs during the Pleistocene glacier advancements from the Alps. Due to the establishment of beech
and pine forest under recent, temperate climate conditions, dispersal between cliffs is no longer possible for rock-dwelling
snails such as T. caelatus. Our results provide basic data for developing a conservation action plan for this endangered gastropod species. 相似文献
23.
We investigated the role of the main olfactory and accessory olfactory systems (MOS and AOS respectively) in the detection of androstenone. We used the following experimental approaches: behavioral, surgical removal of the vomeronasal organ (VNX) followed by histochemical verification and Fos immunohistochemistry. Using a Y-maze paradigm we estimated sensitivity of NZB/B1NJ and CBA/J mice to androstenone. CBA mice were 2,000-fold more sensitive to androstenone than NZB mice. VNX caused a 4- to 16-fold decre... 相似文献
24.
Assessing and reporting heterogeneity in treatment effects in clinical trials: a proposal 总被引:1,自引:0,他引:1
David M Kent Peter M Rothwell John PA Ioannidis Doug G Altman Rodney A Hayward 《Trials》2010,11(1):1-11
Background
This paper presents the study protocol for a pragmatic randomised controlled trial to evaluate the impact of a school based program developed to prevent teenage pregnancy. The program includes students taking care of an Infant Simulator; despite growing popularity and an increasing global presence of such programs, there is no published evidence of their long-term impact. The aim of this trial is to evaluate the Virtual Infant Parenting (VIP) program by investigating pre-conceptual health and risk behaviours, teen pregnancy and the resultant birth outcomes, early child health and maternal health.Methods and Design
Fifty-seven schools (86% of 66 eligible secondary schools) in Perth, Australia were recruited to the clustered (by school) randomised trial, with even randomisation to the intervention and control arms. Between 2003 and 2006, the VIP program was administered to 1,267 participants in the intervention schools, while 1,567 participants in the non-intervention schools received standard curriculum. Participants were all female and aged between 13-15 years upon recruitment. Pre and post-intervention questionnaires measured short-term impact and participants are now being followed through their teenage years via data linkage to hospital medical records, abortion clinics and education records. Participants who have a live birth are interviewed by face-to-face interview. Kaplan-Meier survival analysis and proportional hazards regression will test for differences in pregnancy, birth and abortion rates during the teenage years between the study arms.Discussion
This protocol paper provides a detailed overview of the trial design as well as initial results in the form of participant flow. The authors describe the intervention and its delivery within the natural school setting and discuss the practical issues in the conduct of the trial, including recruitment. The trial is pragmatic and will directly inform those who provide Infant Simulator based programs in school settings.Trial registration
ISRCTN24952438 相似文献25.
Caroline PA de Haan Rauni I Kivistö Marjaana Hakkinen Jukka Corander Marja-Liisa Hänninen 《BMC microbiology》2010,10(1):200
Background
Campylobacter jejuni is the most common bacterial cause of human gastroenteritis worldwide. Due to the sporadic nature of infection, sources often remain unknown. Multilocus sequence typing (MLST) has been successfully applied to population genetics of Campylobacter jejuni and mathematical modelling can be applied to the sequence data. Here, we analysed the population structure of a total of 250 Finnish C. jejuni isolates from bovines, poultry meat and humans collected in 2003 using a combination of Bayesian clustering (BAPS software) and phylogenetic analysis. 相似文献26.
To increase our knowledge about mating-system evolution, we need to understand the relationship between specific floral traits and mating system. Species of Collinsia (Plantaginaceae) vary extensively in mating system; this variation is associated with variation in floral morphology and development and with the timing of self-pollination. Counterintuitively, large-flowered, more outcrossing species tend to have delayed stigma receptivity, reducing the amount of time that the stigma is receptive to cross-pollination before autonomous self-pollination. To understand how the timing of stigma receptivity is related to mating-system evolution, we studied in detail the timing of both stigma receptivity and self-pollination (anther-stigma contact) in two greenhouse-grown populations of large-flowered Collinsia heterophylla. Crosses on emasculated flowers at different stages of floral development always produced seeds, suggesting that cross-fertilization can be effected by pollen arriving prior to physiological receptivity. Phenotypic and genetic variation within populations in the timing of stigma receptivity and anther-stigma contact was substantial, although slightly less for the contact. Despite strong interspecific and interpopulation correlations, we did not find an among-genet phenotypic correlation between the traits. This indicates that each trait may respond independently to selection, and the trait association may be the result of correlational selection. 相似文献
27.
Elisabeth APM Romme Piet Geusens Willem F Lems Erica PA Rutten Frank WJM Smeenk Joop PW van den Bergh Peter ThW van Hal Emiel FM Wouters 《Respiratory research》2015,16(1)
Although osteoporosis and its related fractures are common in patients with COPD, patients at high risk of fracture are poorly identified, and consequently, undertreated. Since there are no fracture prevention guidelines available that focus on COPD patients, we developed a clinical approach to improve the identification and treatment of COPD patients at high risk of fracture. We organised a round-table discussion with 8 clinical experts in the field of COPD and fracture prevention in the Netherlands in December 2013. The clinical experts presented a review of the literature on COPD, osteoporosis and fracture prevention. Based on the Dutch fracture prevention guideline, they developed a 5-step clinical approach for fracture prevention in COPD. Thereby, they took into account both classical risk factors for fracture (low body mass index, older age, personal and family history of fracture, immobility, smoking, alcohol intake, use of glucocorticoids and increased fall risk) and COPD-specific risk factors for fracture (severe airflow obstruction, pulmonary exacerbations and oxygen therapy). Severe COPD (defined as postbronchodilator FEV1 < 50% predicted) was added as COPD-specific risk factor to the list of classical risk factors for fracture. The 5-step clinical approach starts with case finding using clinical risk factors, followed by risk evaluation (dual energy X-ray absorptiometry and imaging of the spine), differential diagnosis, treatment and follow-up. This systematic clinical approach, which is evidence-based and easy-to-use in daily practice by pulmonologists, should contribute to optimise fracture prevention in COPD patients at high risk of fracture. 相似文献
28.
Raimondi A Ferguson SM Lou X Armbruster M Paradise S Giovedi S Messa M Kono N Takasaki J Cappello V O'Toole E Ryan TA De Camilli P 《Neuron》2011,70(6):1100-1114
The existence of neuron-specific endocytic protein isoforms raises questions about their importance for specialized neuronal functions. Dynamin, a GTPase implicated in the fission reaction of endocytosis, is encoded by three genes, two of which, dynamin 1 and 3, are highly expressed in neurons. We show that dynamin 3, thought to play a predominantly postsynaptic role, has a major presynaptic function. Although lack of dynamin 3 does not produce an overt phenotype in mice, it worsens the dynamin 1 KO phenotype, leading to perinatal lethality and a more severe defect in activity-dependent synaptic vesicle endocytosis. Thus, dynamin 1 and 3, which together account for the overwhelming majority of brain dynamin, cooperate in supporting optimal rates of synaptic vesicle endocytosis. Persistence of synaptic transmission in their absence indicates that if dynamin plays essential functions in neurons, such functions can be achieved by the very low levels of dynamin 2. 相似文献
29.
The study of radiobiological effects induced in vitro by low fluences of alpha particles would be significantly enhanced if the precise localization of each particle track in the cell monolayer was known. From this perspective, we developed a new method based on tailor-made UV-radiation-cured CR-39, the production of which is described. Its validation both as a petri dish and as solid-state nuclear track detectors is demonstrated. With respect to the demands on solid-state nuclear track detectors in such experiments, these biologically compatible detectors have a controlled micrometric thickness that allows them to be crossed by the alpha particles. In this study, we present a method for obtaining 10-mum-thick CR-39, its chemical characterization, and its properties as a solid-state nuclear track detector under the environmental conditions of radiobiological experiments. The experimental studies performed with 3.5 MeV alpha particles show that their transmitted energy is sufficient enough to cross the entire cellular volume. Under optimal conditions, etched tracks are clearly defined 2 h after etching. Moreover, the UV-radiation-cured CR-39 represents an essentially zero background that is due to the short time between the production and use of the polymer. Under a confocal microscope, this thin solid-state nuclear track detector allows the precise localization of the impact parameter at the subcellular level. 相似文献
30.
Oxidative cleavage of poly(cis-1,4-isoprene) by rubber oxygenase RoxA purified from Xanthomonas sp. was investigated in the presence of different combinations of (16)O(2), (18)O(2), H(2)(16)O, and H(2)(18)O. 12-oxo-4,8-dimethyl-trideca-4,8-diene-1-al (ODTD; m/z 236) was the main cleavage product in the absence of (18)O-compounds. Incorporation of one (18)O atom in ODTD was found if the cleavage reaction was performed in the presence of (18)O(2) and H(2)(16)O. Incubation of poly(cis-1,4-isoprene) (with RoxA) or of isolated unlabeled ODTD (without RoxA) with H(2)(18)O in the presence of (16)O(2) indicated that the carbonyl oxygen atoms of ODTD significantly exchanged with oxygen atoms derived from water. The isotope exchange was avoided by simultaneous enzymatic reduction of both carbonyl functions of ODTD to the corresponding dialcohol (12-hydroxy-4,8-dimethyl-trideca-4,8-diene-1-ol (HDTD; m/z 240) during RoxA-mediated in vitro cleavage of poly(cis-1,4-isoprene). In the presence of (18)O(2), H(2)(16)O, and alcohol dehydrogenase/NADH, incorporation of two atoms of (18)O into the reduced metabolite HDTD was found (m/z 244), revealing that RoxA cleaves rubber by a dioxygenase mechanism. Based on the labeling results and the presence of two hemes in RoxA, a model of the enzymatic cleavage mechanism of poly(cis-1,4-isoprene) is proposed. 相似文献