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71.
Rachele Beghin Emanuele Lingua Matteo Garbarino Michele Lonati Giovanni Bovio Renzo Motta Raffaella Marzano 《Ecological Engineering》2010,36(10):1365-1372
It is frequently believed that a post-fire environment requires immediate actions in order to be restored. Salvage logging followed by plantation is a common post-fire restoration practice in many forests of the northwestern Italian Alps.The objectives of this study were to assess the impact of active and passive management techniques on the restoration of a burned area of the Aosta Valley and to determine which approach is the most suitable for enhancing Pinus sylvestris regeneration after stand replacing wildfires.The influence of five management options (no intervention; salvage logging; broadleaves plantation; Larix decidua plantation; P. sylvestris or Pseudotsuga menziesii plantation) and environmental variables on natural regeneration structure and composition was evaluated through direct gradient analysis.Pinus sylvestris and Populus tremula were the dominant tree species (40 and 29%, respectively) in the regeneration layer. Density, size, and structural diversity of natural regeneration were higher in the no intervention area. The proximity to forest edge was found to be the most important environmental variable.This study provided evidence that taking advantage of natural restoration processes may be a suitable alternative strategy to the active restoration practices adopted according to the Aosta Valley policy of post-fire management. 相似文献
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Marta Deganuto Laura Cesaratto Cristina Bellarosa Raffaella Calligaris Sandra Vilotti Giovanni Renzone Rossana Foti Andrea Scaloni Stefano Gustincich Franco Quadrifoglio Claudio Tiribelli Gianluca Tell 《Proteomics》2010,10(8):1645-1657
Unconjugated bilirubin (UCB) is a powerful antioxidant and a modulator of cell growth through the interaction with several signal transduction pathways. Although newborns develop a physiological jaundice, in case of severe hyperbilirubinemia UCB may become neurotoxic causing severe long‐term neuronal damages, also known as bilirubin encephalopathy. To investigate the mechanisms of UCB‐induced neuronal toxicity, we used the human neuroblastoma cell line SH‐SY5Y as an in vitro model system. We verified that UCB caused cell death, in part due to oxidative stress, which leads to DNA damage and cell growth reduction. The mechanisms of cytotoxicity and cell adaptation to UCB were studied through a proteomic approach that identified differentially expressed proteins involved in cell proliferation, intracellular trafficking, protein degradation and oxidative stress response. In particular, the results indicated that cells exposed to UCB undertake an adaptive response that involves DJ‐1, a multifunctional neuroprotective protein, crucial for cellular oxidative stress homeostasis. This study sheds light on the mechanisms of bilirubin‐induced neurotoxicity and might help to design a strategy to prevent or ameliorate the neuronal damages leading to bilirubin encephalopathy. 相似文献
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Age and nutrient limitation enhance polyunsaturated aldehyde production in marine diatoms 总被引:4,自引:0,他引:4
Skeletonema marinoi produces 2,4-heptadienal, 2,4-octadienal, and 2,4,7-octatrienal, the latter only in traces. In nutrient-replete cultures, the production of potentially defensive polyunsaturated aldehydes (PUA) increases from the exponential to the stationary phase of growth from 1.2 fmol cell(-1) (+/-0.4 fmol cell(-1) SD) to 4.2 fmol cell(-1) (+/-1.0 fmol cell(-1) SD), with 2,4-heptadienal as the dominant aldehyde. The plasticity of PUA production with age of the culture supports the hypothesis of a direct link between toxin production and cell physiological state. N- and P-limited cells in stationary phase produced 1.4 and 1.8 fold higher amounts of PUA than control cultures and 10.7 and 4.6 times higher PUAs when compared to their own exponential growth phase, respectively. The increase in PUA production in the nutrient-limited cultures was not paralleled by an increase in the total amount of precursor fatty acids indicating that physiological stress might trigger an enhanced expression or activity of the enzymes responsible for PUA production, i.e. chemical defense increase in aged and nutrient-stressed diatoms. If this holds true during blooms, grazers feeding at the end of a bloom would be more affected than early-bloom grazers. 相似文献
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In common with most Old World Gesneriaceae; Streptocarpus Lindl. shows anisocotylous growth, i.e., the continuous growth of one cotyledon after germination. Linked to this phenomenon
is an unorthodox behaviour of the shoot apical meristem (SAM) that determines the growth pattern of acaulescent species (subgenus
Streptocarpus). In contrast caulescent species develop a conventional central post-embryonic SAM (mainly subgenus Streptocarpella). We used S. rexii Lindl. as a model to investigate anisocotyly and meristem initiation in Streptocarpus by using histological techniques and analyses of the expression pattern of the meristematic marker SrSTM1 during ontogeny. In contrast to Arabidopsis thaliana (L.) Heynh., S. rexii does not establish a SAM during embryogenesis, and the first evidence of a SAM-like structure occurs during post-embryonic
development on the axis (the petiolode) between the two cotyledons. The expression pattern of SrSTM1 suggests a function in maintaining cell division activity in the cotyledons before becoming localized in the basal meristem,
initially at the proximal ends of both cotyledons, later at the base of the continuously growing macrocotyledon, and the groove
meristem on the petiolode. The latter is equivalent to a displaced SAM seemingly originating de novo under the influence of
endogenous factors. Applied cytokinin retains SrSTM1expression in the small cotyledon, thus promoting isocotyly and re-establishment of a central post-embryonic SAM. Hormone-dependent
delocalization of the process of meristem development could underlie anisocotyly and the unorthodox SAM formation in Streptocarpus.
Electronic supplementary material Supplementary material is available in the online version of this article at and is accessible for authorized users. 相似文献
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Atmospheric formaldehyde (CH(2)O) was detected under continuous flow conditions by an on-line system comprising of a wet scrubber for a continuous transfer of the pollutant to an aqueous solution, a micro-reactor containing immobilized formaldehyde dehydrogenase (FDH) and a conductometric transducer. By this system atmospheric formaldehyde concentrations in the range 0.05-2 ppm were detected with a sensitivity of 20 microS/ppm. In this concentration range the immobilized enzyme oxidized all the sampled formaldehyde molecules to formic acid, avoiding cumbersome calibration procedures. The operational stability of the biosensor was at least 3 months, working continuously 10 h/day at room temperature. 相似文献