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21.
Japanese knotweed s.l. comprises Fallopia japonica, F. sachalinensis, F. × bohemica and any F2s or backcrosses. The parental taxa were introduced from the East to the West as garden ornamentals in the nineteenth
century, and soon spread beyond the confines of the garden to become widespread and persistent weeds. Since only female F. japonica var. japonica was introduced, its impressive spread has occurred solely by vegetative means. However, the initial lack of genetic variability
has been complemented by an extensive series of hybridisations in the adventive range. We examine the history, spread, reproductive
biology and ecological impact of these species in the West. The role and importance of polyploidy and hybridisation in their
invasion of the West is discussed, as are the implications of these factors for the potential further evolution of the group. 相似文献
22.
Abarca Héctor Morán-Ordoñez Alejandra Villero Dani Guinart Daniel Brotons Lluís Hermoso Virgilio 《Biodiversity and Conservation》2022,31(4):1197-1215
Biodiversity and Conservation - Biodiversity keeps declining in the European Union despite the large conservation effort done over the last decades. The Biodiversity Strategy for 2030 aims to... 相似文献
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24.
Musto H Naya H Zavala A Romero H Alvarez-Valín F Bernardi G 《Biochemical and biophysical research communications》2006,347(1):1-3
Two years ago, we showed that positive correlations between optimal growth temperature (T(opt)) and genome GC are observed in 15 out of the 20 families of prokaryotes we analyzed, thus indicating that "T(opt) is one of the factors that influence genomic GC in prokaryotes". Our results were disputed, but these criticisms were demonstrated to be mistaken and based on misconceptions. In a recent report, Wang et al. [H.C. Wang, E. Susko, A.J. Roger, On the correlation between genomic G+C content and optimal growth temperature in prokaryotes: data quality and confounding factors, Biochem. Biophys. Res. Commun. 342 (2006) 681-684] criticize our results by stating that "all previous simple correlation analyses of GC versus temperature have ignored the fact that genomic GC content is influenced by multiple factors including both intrinsic mutational bias and extrinsic environmental factors". This statement, besides being erroneous, is surprising because it applies in fact not to ours but to the authors' article. Here, we rebut the points raised by Wang et al. and review some issues that have been a matter of debate, regarding the influence of environmental factors upon GC content in prokaryotes. Furthermore, we demonstrate that the relationship that exists between genome size and GC level is valid for aerobic, facultative, and microaerophilic species, but not for anaerobic prokaryotes. 相似文献
25.
Rojas P Garduño B Rojas C Vigueras RM Rojas-Castañeda J Rios C Serrano-Garcia N 《Neurochemical research》2001,26(11):1245-1251
EGb761 has been suggested to be an antioxidant and free radical scavenger. Excess generation of free radicals, leading to lipid peroxidation (LP), has been proposed to play a role in the damage to striatal neurons induced by 1-methyl-4-phenylpyridinium (MPP+). We investigated the effects of EGb761 pretreatment on MPP+ neurotoxicity. C-57 black mice were pretreated with EGb761 for 17 days at different doses (0.63, 1.25, 2.5, 5 or 10 mg/kg) followed by administration of MPP+, (0.18, 0.36 or 0.72 mg/kg). LP was analyzed in corpus striatum at 30 min, 1 h, 2 h and 24 h after MPP+ administration. Striatal dopamine content was analyzed by HPLC at the highest EGb761 dose at 2 h and 24 h after MPP+ administration. MPP+-induced LP was blocked (100%) by EGb761 (10 mg/kg). Pretreatment with EGb761 partially prevented (32%) the dopamine-depleting effect of MPP+ at 24 h. These results suggest that supplements of EGb761 may be effective at preventing MPP+-induced oxidative stress. 相似文献
26.
Jorge M. Lopez-Calderon Rafael Riosmena-Rodríguez Jorge Torre Alf Meling Xavier Basurto 《Biodiversity and Conservation》2016,25(2):261-273
Eelgrass (Zostera marina) population estimates show a decreasing trend worldwide in the second half of the twentieth century. Mexico lacks long-term time series to determine trends for major eelgrass populations and has made no conservation efforts. Therefore, we present the first report on the historic presence of this annual coastal ecosystem in two wetlands of the Gulf of California (GC), the Infiernillo Channel (CIF, largest Z. marina population inside GC) and Concepcion Bay (BCP, the only eelgrass population along GC’s west coast), combining field surveys (1999–2010), aerial photography (2000–2010), satellite imagery (1972–2005), and published reports (1994–2007). Three parameters were used as indicators of conservation status: shoot density, seed banks, and aerial coverage. Average shoot density in the CIF (741 shoots m?2) was 3.8 times higher than in BCP (194 shoots m?2), and average seed bank density was similar in both wetlands (17,442 seeds m?2 vs. 17,000 seeds m?2). Opportunistic seagrass Ruppia maritima was observed in both wetlands, with higher abundance in summer when Z. marina disappears due to high water temperatures. Eelgrass coverage was three orders of magnitude greater in the CIF (9725 ha) than in BCP (3 ha). The striking difference between these wetlands is the lack of environmental protection for BCP and the protection of the CIF by the Seri indigenous community, which increases human pressure in the former, putting it at high risk of disappearing. Conservation of eelgrass meadows is not only necessary to preserve their ecosystem services but to insure the survival of migratory populations (Pacific brant goose, Branta bernicla), endangered species (Black turtle, Chelonia mydas), and fisheries-related species. 相似文献
27.
Emma del Carmen Macías-Cortés Lidia Llanes-González Leopoldo Aguilar-Faisal Juan Asbun-Bojalil 《PloS one》2015,10(3)
Background
Perimenopausal period refers to the interval when women''s menstrual cycles become irregular and is characterized by an increased risk of depression. Use of homeopathy to treat depression is widespread but there is a lack of clinical trials about its efficacy in depression in peri- and postmenopausal women. The aim of this study was to assess efficacy and safety of individualized homeopathic treatment versus placebo and fluoxetine versus placebo in peri- and postmenopausal women with moderate to severe depression.Methods/Design
A randomized, placebo-controlled, double-blind, double-dummy, superiority, three-arm trial with a 6 week follow-up study was conducted. The study was performed in a public research hospital in Mexico City in the outpatient service of homeopathy. One hundred thirty-three peri- and postmenopausal women diagnosed with major depression according to DSM-IV (moderate to severe intensity) were included. The outcomes were: change in the mean total score among groups on the 17-item Hamilton Rating Scale for Depression, Beck Depression Inventory and Greene Scale, after 6 weeks of treatment, response and remission rates, and safety. Efficacy data were analyzed in the intention-to-treat population (ANOVA with Bonferroni post-hoc test).Results
After a 6-week treatment, homeopathic group was more effective than placebo by 5 points in Hamilton Scale. Response rate was 54.5% and remission rate, 15.9%. There was a significant difference among groups in response rate definition only, but not in remission rate. Fluoxetine-placebo difference was 3.2 points. No differences were observed among groups in the Beck Depression Inventory. Homeopathic group was superior to placebo in Greene Climacteric Scale (8.6 points). Fluoxetine was not different from placebo in Greene Climacteric Scale.Conclusion
Homeopathy and fluoxetine are effective and safe antidepressants for climacteric women. Homeopathy and fluoxetine were significantly different from placebo in response definition only. Homeopathy, but not fluoxetine, improves menopausal symptoms scored by Greene Climacteric Scale.Trial Registration
ClinicalTrials.gov NCT01635218Protocol Publication
http://www.trialsjournal.com/content/14/1/105. 相似文献28.
29.
30.
Considerable knowledge exists about the effect of aluminium (Al) on root vitality, but whether elevated levels of Al affect
soil microorganisms is largely unknown. We thus compared soils from Al-treated and control plots of a field experiment with
respect to microbial and chemical parameters, as well as root growth and vitality. The field experiment was established in
a 50-year-old Norway spruce (Picea abies L.) stand where no Al or low concentrations of Al had been added every 7–10 days during the growth season for 7 years. Analysis
of soil solutions collected using zero tension lysimeters and porous suction cups showed that Al treatment lead to increased
concentrations of Al, Ca and Mg and lower pH and [Ca + Mg + K/Al] molar ratio. Corresponding soil analyses showed that soil
pH remained unaffected (pH 3.8), that exchangeable Al increased, while exchangeable Ca and Mg decreased due to the Al treatment.
Root in-growth into cores placed in the upper 20 cm of the soil during three growth seasons was not affected by Al additions,
neither was nutrient concentration or mortality of these roots. The biomass of some taxonomic groups of soil microorganisms,
analyzed using specific membrane components (phospholipid fatty acids; PLFAs), was clearly affected by the imposed Al treatment,
both in the organic soil horizon and in the underlying mineral soil. Microbial community structure in both horizons was also
clearly modified by the Al treatment. Shifts in PLFA trans/cis ratios indicative of short term physiological stress were not observed. Yet, aluminium stress was indicated both by changes
in community structure and in ratios of single PLFAs for treated/untreated plots. Thus, soil microorganisms were more sensitive
indicators of subtle chemical changes in soil than chemical composition and vitality of roots. 相似文献