58 research outputs found

    Evaluation of Allelopathic Potential of Rumex dentatus Root Extract and Allelochemicals on Cicer arietinum

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    The present study aimed to evaluate the allelopathic potential of root extract of Rumex dentatus L. and various allelochemicals on some physiological parameters in roots of Cicer arietinum L. The tested allelochemicals were benzoic, caffeic, cinnamic, ferulic, gallic, sinapic and vanillic acids. Seed germination of Cicer was inhibited by Rumex extract. Lipid peroxidation and hydrogen peroxide production increased gradually in response to extract concentration as well as allelochemicals treatment. The total soluble protein decreased whereas the total phenol increased under the various treatments. The activities of superoxide dismutase (SOD: 1.15.1.1) and catalase (CAT: 1.11.1.6) increased continuously with increasing extract concentration. However, peroxidase (POD: 1.11.1.7) increased sharply at 2% (w/v) followed by reduction at the higher concentrations and reached 1.1 U g-1 fresh weight at 10% (w/v) which was still higher than that of the control value. Ferulic acid was the most effective inducer for SOD activity followed by cinnamic acid. The POD activity increased remarkably particularly with cinnamic, benzoic and gallic acids. Sinapic, ferulic and coumaric acids enhanced CAT activity by 150.4%, 139.5% and 124.4%, respectively. The results reveal the possible use of R. dentatus as bioherbicide

    Plant communities along the international coastal highway of Nile delta, Egypt

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    The construction of highways promotes several changes in the roadside habitat, vegetation, and plant invasion. The present study aimed to describe the plant communities-environment interactions of the international coastal highway from Port-Said to Abu-Qir, northern Nile delta coast of Egypt. A total of 146 species (83 annuals, 4 biennials, and 59 perennials), belonging to 116 genera and 33 families were recorded in 80 stands. The Mediterranean chorotype is the most represented. The cluster analysis of stands yielded four communities. The community I was dominated by Silybum mariannum, community II was dominated by Mesembryanthemum crystalinum, Community III is the largest one and was co-dominated by Hordeum murinum and Senecio glaucus and community IV was co-dominated by Cakile maritima and S. glaucus. Diversity indices showed more richness of communities II and more evenness of community IV. Electric conductivity, porosity, soil texture, Na+, Cl- and bicarbonate showed significant variation among communities. The soil of C. maritima and S. glaucus community was more saline (1.78 ms cm-1). The application of CCA showed that communities II and III were mainly correlated with salinity and organic matter. The present study revealed that roadside habitat of the international coastal highway dominated by different plant communities which correlated with the habitat structure, salinity, and anthropogenic activities. Furthermore, nine invasive species were recorded in this study which could be attributed to the increment of human activities after the construction of the highway

    Anatomical investigation of three emergent Cyperus species growing naturally on the canal banks of the Nile delta, Egypt

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    The genus Cyperus is a large genus with about 600 species, widespread all over the world. The present work contains anatomical descriptions of culms and leaves anatomy of three taxa of Cyprus spp. (Cyperus alopecuroides, C. articulates and C. papyrus). Cyperus spp. were collected from canal banks of Nile Delta. The culms in transverse section of all examined species were triangular except for C. articulates which was circular. The ground tissue differentiated into parenchyma cells with thin walls and small, triangular intercellular spaces, while C. articulates has large hollow pith. Vascular bundles are small, angular and scattered throughout the thin-walled ground tissue. Leaf anatomy of C. alopecuroides and C. papyrus is an example of the isobilateral mesophyll with palisade parenchyma on both sides, enlarged epidermal cells referred to as hing cells found in the middle of the blade. The center of the leaf is occupied by a large vascular bundle surrounded by a bundle sheath.   &nbsp

    Different pathways but same result? Comparing chemistry and biological effects of burned and decomposed litter

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    Litter burning and biological decomposition are oxidative processes co-occurring in many terrestrial ecosystems, producing organic matter with different chemical properties and differently affecting plant growth and soil microbial activity. Here, we tested the chemical convergence hypothesis (i.e. materials with different initial chemistry tend to converge towards a common profile, with similar biological effects, as the oxidative process advances) for burning and decomposition. We compared the molecular composition of 63 organic materials - 7 litter types either fresh, decomposed for 30, 90, 180 days, or heated at 100, 200, 300, 400, 500 \ub0C - as assessed by 13C NMR. We used litter water extracts (5% dw) as treatments in bioassays on plant (Lepidium sativum) and fungal (Aspergillus niger) growth, and a washed quartz sand amended with litter materials (0.5 % dw) to assess heterotrophic respiration by CO2 flux chamber. We observed different molecular variations for materials either burning (i.e. a sharp increase of aromatic C and a decrease of most other fractions above 200 \ub0C) or decomposing (i.e. early increase of alkyl, methoxyl and N-alkyl C and decrease of O-alkyl and di-O-alkyl C fractions). Soil respiration and fungal growth progressively decreased with litter age and temperature. Plant growth underwent an inhibitory effect by untreated litter, more and less rapidly released over decomposing and burning materials, respectively. Correlation analysis between NMR and bioassay data showed that opposite responses for soil respiration and fungi, compared to plants, are related to essentially the same C molecular types. Our findings suggest a functional convergence of decomposed and burnt organic substrates, emerging from the balance between the bioavailability of labile C sources and the presence of recalcitrant and pyrogenic compounds, oppositely affecting different trophic levels

    Faster N release, but not C loss, from leaf litter of invasives compared to native species in mediterranean ecosystems

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    Plant invasions can have relevant impacts on biogeochemical cycles, whose extent, in Mediterranean ecosystems, have not yet been systematically assessed comparing litter carbon (C) and nitrogen (N) dynamics between invasive plants and native communities. We carried out a 1-year litterbag experiment in 4 different plant communities (grassland, sand dune, riparian and mixed forests) on 8 invasives and 24 autochthonous plant species, used as control. Plant litter was characterized for mass loss, N release, proximate lignin and litter chemistry by 13C CPMAS NMR. Native and invasive species showed significant differences in litter chemical traits, with invaders generally showing higher N concentration and lower lignin/N ratio. Mass loss data revealed no consistent differences between native and invasive species, although some woody and vine invaders showed exceptionally high decomposition rate. In contrast, N release rate from litter was faster for invasive plants compared to native species. N concentration, lignin content and relative abundance of methoxyl and N-alkyl C region from 13C CPMAS NMR spectra were the parameters that better explained mass loss and N mineralization rates. Our findings demonstrate that during litter decomposition invasive species litter has no different decomposition rates but greater N release rate compared to natives. Accordingly, invasives are expected to affect N cycle in Mediterranean plant communities, possibly promoting a shift of plant assemblages

    Windstorm disturbance triggers multiple species invasion in an urban Mediterranean forest

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    Plant invasion in forest ecosystems is a serious ecological and economic issue, deserving attention by researchers, managers and policy-makers worldwide. Many invasive plants have been reported as early successional species able to colonize disturbed areas following abrupt changes in microhabitat and resource availability. We investigated disturbance effects of a severe windstorm generated by a wet microburst (hail and rain at 160 mm h-1) remarkably affecting the canopy cover of an old-growth Quercus ilex urban forest in Southern Italy. This stand-replacing disturbance produced a mosaic of 103 gaps, 5.6 to 1632 m2 in size, over an area of 1.53 ha, uprooting 76% of the trees and decreasing thereby 85% of the standing above-ground dry biomass into the gaps. By intensive monitoring we compared above- and below-ground microclimate, soil moisture and mineral N availability in paired disturbed and control areas of the study forest. Within newly formed gaps we observed a seasonally consistent 70% higher content of nitrate nitrogen, 29% and 47% decreases of ammonia nitrogen in summer and autumn, respectively, and a higher moisture in topsoil, in addition to different above- and below-ground microclimatic conditions, with canopy cover mitigating extreme temperatures. One year after the windstorm, the microhabitat shift promoted the establishment in gaps of 15 native and 10 alien taxa previously absent in both disturbed and control plots. In such conditions, the rarefaction of the dominant Q. ilex canopy cover and the occurrence of empty niches prone to invasion could dramatically affect the local community structure and diversity. Our data indicate that stand-replacing windstorm can transiently transform the studied urban evergreen forest to an early allogenic successional community dominated, in the medium and large gaps, by annual and perennial non-native species. This is particularly relevant under a perspective of possible increasing frequency of windstorm events in the Mediterranean region in the near future

    HER2/neu expression status of post BCG recurrent non-muscle-invasive bladder urothelial carcinomas in relation to their primary ones

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    Background: Transurethral resection (TUR) followed by adjuvant therapy is still the treatment of choice of Non-Muscle-Invasive Bladder Urothelial Carcinoma (NMIBUC). However, recurrence is one of the most troublesome features of these lesions. Early second resection and adjuvant BCG therapy has been shown to improve the outcome. Objective: To evaluate the prognostic value of C-erbB-2 (HER2/neu) expression status in Non-Muscle-Invasive Bladder Urothelial Carcinoma cases, before and after intravesical Bacillus Calmette Guerin (BCG immunotherapy). Materials and methods: HER2/neu expression was studied in 120 (Ta-T1) Non-Muscle-Invasive Urothelial Carcinoma cases. The expression was evaluated and compared to the expression after Bacillus Calmette Guerin (BCG) immunotherapy. Results: HER2/neu expression in low and high grade of the Non- Muscle-Invasive Urothelial Carcinoma was (38%) and (83%) respectively. The difference of the expression rates by tumor grade was statistically significant. In recurring lesions post BCG therapy, C-erbB-2 expression was markedly decreased (31.6%) when compared to its expression before therapy (65%). Conclusions: The HER2/neu expression increased as the tumor grade rose. The reduction in expression following BCG treatment in Non-Invasive transitional cell carcinoma cases could reflect a reduction of the potential malignancy of the tumor

    Antimicrobial resistance among migrants in Europe: a systematic review and meta-analysis

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    BACKGROUND: Rates of antimicrobial resistance (AMR) are rising globally and there is concern that increased migration is contributing to the burden of antibiotic resistance in Europe. However, the effect of migration on the burden of AMR in Europe has not yet been comprehensively examined. Therefore, we did a systematic review and meta-analysis to identify and synthesise data for AMR carriage or infection in migrants to Europe to examine differences in patterns of AMR across migrant groups and in different settings. METHODS: For this systematic review and meta-analysis, we searched MEDLINE, Embase, PubMed, and Scopus with no language restrictions from Jan 1, 2000, to Jan 18, 2017, for primary data from observational studies reporting antibacterial resistance in common bacterial pathogens among migrants to 21 European Union-15 and European Economic Area countries. To be eligible for inclusion, studies had to report data on carriage or infection with laboratory-confirmed antibiotic-resistant organisms in migrant populations. We extracted data from eligible studies and assessed quality using piloted, standardised forms. We did not examine drug resistance in tuberculosis and excluded articles solely reporting on this parameter. We also excluded articles in which migrant status was determined by ethnicity, country of birth of participants' parents, or was not defined, and articles in which data were not disaggregated by migrant status. Outcomes were carriage of or infection with antibiotic-resistant organisms. We used random-effects models to calculate the pooled prevalence of each outcome. The study protocol is registered with PROSPERO, number CRD42016043681. FINDINGS: We identified 2274 articles, of which 23 observational studies reporting on antibiotic resistance in 2319 migrants were included. The pooled prevalence of any AMR carriage or AMR infection in migrants was 25·4% (95% CI 19·1-31·8; I2 =98%), including meticillin-resistant Staphylococcus aureus (7·8%, 4·8-10·7; I2 =92%) and antibiotic-resistant Gram-negative bacteria (27·2%, 17·6-36·8; I2 =94%). The pooled prevalence of any AMR carriage or infection was higher in refugees and asylum seekers (33·0%, 18·3-47·6; I2 =98%) than in other migrant groups (6·6%, 1·8-11·3; I2 =92%). The pooled prevalence of antibiotic-resistant organisms was slightly higher in high-migrant community settings (33·1%, 11·1-55·1; I2 =96%) than in migrants in hospitals (24·3%, 16·1-32·6; I2 =98%). We did not find evidence of high rates of transmission of AMR from migrant to host populations. INTERPRETATION: Migrants are exposed to conditions favouring the emergence of drug resistance during transit and in host countries in Europe. Increased antibiotic resistance among refugees and asylum seekers and in high-migrant community settings (such as refugee camps and detention facilities) highlights the need for improved living conditions, access to health care, and initiatives to facilitate detection of and appropriate high-quality treatment for antibiotic-resistant infections during transit and in host countries. Protocols for the prevention and control of infection and for antibiotic surveillance need to be integrated in all aspects of health care, which should be accessible for all migrant groups, and should target determinants of AMR before, during, and after migration. FUNDING: UK National Institute for Health Research Imperial Biomedical Research Centre, Imperial College Healthcare Charity, the Wellcome Trust, and UK National Institute for Health Research Health Protection Research Unit in Healthcare-associated Infections and Antimictobial Resistance at Imperial College London
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