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41.
The occurrence of covalent bonds between residual lignin and polysaccharides in birch and pine kraft pulps was investigated by specific enzymatic treatments. Pure enzymes degrading cellulose, xylan and mannan were used both separately and in combination. Comparison of the molar masses of polysaccharides and lignin in the orginal pulps and in the residual pulps after enzymatic treatments showed that residual lignin in birch kraft pulp is linked at least to xylan. A minor portion may also be linked to cellulose. In pine kraft pulp some of the residual lignin appears to be linked to cellulose, glucomannan and xylan. The linkages between lignin and cellulose and hemicelluloses may be either native or formed during pulp processing. The results also provided new information on the synergistic action of cellulose- and hemicellulose-degrading enzymes on pulp fibres. The synergism appears to be mainly due to the structure of the pulp fibres, with different layers of cellulose sheets, hemicelluloses and lignin. On the other hand the results also provided information about fibre structure. The degradation of xylan clearly enhanced the action of enzymes on cellulose, suggesting that xylan partially covers the cellulose. A similar phenomenon was not observed in the simultaneous hydrolysis of glucomannan and cellulose. However, the results suggest that glucomannan does interact with cellulose, possibly by non-covalent linkages. Received: 8 July 1998 / Received revision: 7 October 1998 / Accepted: 11 October 1998  相似文献   
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The human δ opioid receptor (hδOR) is a G-protein-coupled receptor that is mainly involved in the modulation of pain and mood. Only one nonsynonymous single nucleotide polymorphism (T80G) has been described, causing Phe27Cys substitution in the receptor N-terminus and showing association with substance dependence. In this study, we expressed the two hδOR variants in a heterologous expression system with an identical genetic background. They differed greatly during early steps of biosynthesis, displaying a significant difference in the maturation efficiency (50% and 85% for the Cys27 and Phe27 variants, respectively). The Cys27 variant also showed accumulation in pre-Golgi compartments of the secretory pathway and impaired targeting to endoplasmic reticulum (ER)-associated degradation following long-term expression. In addition, the cell surface receptors of the Cys27 variant internalized constitutively. Replacement of phenylalanine with other amino acids revealed that cysteine at position 27 decreased the mature receptor/precursor ratio most extensively, suggesting a thiol-mediated retention of precursors in the ER. However, cysteine did not cause a major folding defect because pharmacological characteristics and the maturation kinetics of the variants were identical, and an opioid antagonist was able to enhance the maturation of both variants. We conclude that, instead of causing loss of function, Phe27Cys polymorphism of the hδOR causes a gain-of-function phenotype, which may have implications for the regulation of receptor expression at the cell surface and possibly also for the susceptibility to pathophysiological states.  相似文献   
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Both adenosine and nitric oxide (NO) are known for their role in sleep homeostasis, with the basal forebrain (BF) wakefulness center as an important site of action. Previously, we reported a cascade of homeostatic events, wherein sleep deprivation (SD) induces the production of inducible nitric oxide synthase (iNOS)-dependent NO in BF, leading to enhanced release of extracellular adenosine. In turn, increased BF adenosine leads to enhanced sleep intensity, as measured by increased non-rapid eye movement sleep EEG delta activity. However, the presence and time course of similar events in cortex has not been studied, although a frontal cortical role for the increase in non-rapid eye movement recovery sleep EEG delta power is known. Accordingly, we performed simultaneous hourly microdialysis sample collection from BF and frontal cortex (FC) during 11 h SD. We observed that both areas showed sequential increases in iNOS and NO, followed by increases in adenosine. BF increases began at 1 h SD, whereas FC increases began at 5 h SD. iNOS and Fos-double labeling indicated that iNOS induction occurred in BF and FC wake-active neurons. These data support the role of BF adenosine and NO in sleep homeostasis and indicate the temporal and spatial sequence of sleep homeostatic cascade for NO and adenosine.  相似文献   
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Kariola T  Brader G  Li J  Palva ET 《The Plant cell》2005,17(1):282-294
Accumulation of reactive oxygen species (ROS) is central to plant response to several pathogens. One of the sources of ROS is the chloroplast because of the photoactive nature of the chlorophylls. Chlorophyllase 1 (encoded by AtCLH1) of Arabidopsis thaliana is quickly induced after tissue damage (e.g., caused by the bacterial necrotroph Erwinia carotovora or the necrotrophic fungus Alternaria brassicicola). RNA interference silencing of AtCLH1 resulted in failure to degrade free chlorophyll after tissue damage and in resistance to E. carotovora. Both inoculation with E. carotovora and exposure to high light caused elevated accumulation of hydrogen peroxide in AtCLH1 silenced plants. This was accompanied by expression of marker genes for systemic acquired resistance and induction of antioxidant defenses. Interestingly, downregulation of AtCLH1 resulted in increased susceptibility to A. brassicicola, resistance to which requires jasmonate signaling. We propose that AtCLH1 is involved in plant damage control and can modulate the balance between different plant defense pathways.  相似文献   
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Personality features are associated with individual differences in daily emotional life, such as negative and positive affectivity, affect variability and affect reactivity. The existing literature is somewhat mixed and inconclusive about the nature of these associations. The aim of this study was to shed light on what personality features represent in daily life by investigating the effect of the Five Factor traits on different daily emotional processes using an ecologically valid method. The Experience Sampling Method was used to collect repeated reports of daily affect and experiences from 104 healthy university students during one week of their normal lives. Personality traits of the Five Factor model were assessed using NEO Five Factor Inventory. Hierarchical linear modeling was used to analyze the effect of the personality traits on daily emotional processes. Neuroticism predicted higher negative and lower positive affect, higher affect variability, more negative subjective evaluations of daily incidents, and higher reactivity to stressors. Conscientiousness, by contrast, predicted lower average level, variability, and reactivity of negative affect. Agreeableness was associated with higher positive and lower negative affect, lower variability of sadness, and more positive subjective evaluations of daily incidents. Extraversion predicted higher positive affect and more positive subjective evaluations of daily activities. Openness had no effect on average level of affect, but predicted higher reactivity to daily stressors. The results show that the personality features independently predict different aspects of daily emotional processes. Neuroticism was associated with all of the processes. Identifying these processes can help us to better understand individual differences in daily emotional life.  相似文献   
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A new type of pyoderma was detected in Finnish fur animals in 2007. The disease continues to spread within and between farms, with severe and potentially fatal symptoms. It compromises animal welfare and causes considerable economic losses to farmers. A case-control study was performed in 2010–2011 to describe the entity and to identify the causative agent. Altogether 99 fur animals were necropsied followed by pathological and microbiological examination. The data indicated that the disease clinically manifests in mink (Neovison vison) by necrotic dermatitis of the feet and facial skin. In finnraccoons (Nyctereutes procyonoides), it causes painful abscesses in the paws. Foxes (Vulpes lagopus) are affected by severe conjunctivitis and the infection rapidly spreads to the eyelids and facial skin. A common finding at necropsy was necrotic pyoderma. Microbiological analysis revealed the presence of a number of potential causative agents, including a novel Streptococcus sp. The common finding from all diseased animals of all species was Arcanobacterium phocae. This bacterium has previously been isolated from marine mammals with skin lesions but this is the first report of A. phocae isolated in fur animals with pyoderma. The results obtained from this study implicate A. phocae as a potential causative pathogen of fur animal epidemic necrotic pyoderma (FENP) and support observations that the epidemic may have originated in a species -shift of the causative agent from marine mammals. The variable disease pattern and the presence of other infectious agents (in particular the novel Streptococcus sp.) suggest a multifactorial etiology for FENP, and further studies are needed to determine the environmental, immunological and infectious factors contributing to the disease.  相似文献   
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Ecosystem services are vital for humans in urban regions. However, urban development poses a great risk for the ability of ecosystems to provide these services. In this paper we first address the most important ecosystem services in functional urban regions in Finland. Well accessible and good quality recreational ecosystem services, for example, provided by urban nature, are an important part of a high-quality living environment and important for public health. Vegetation of urban regions can have a role in carbon dioxide sequestration and thus in climate change mitigation. For instance, estimates of carbon sinks can be compared to total CO2 emissions of an urban region, and the municipality can aim at both increasing carbon sinks and decreasing CO2 emissions with proper land-use planning. Large and contiguous core nature areas, smaller green areas and ecological connections between them are the essence of regional ecological networks and are essential for maintaining interconnected habitats for species and thus biological diversity. Thus, both local and regional level ecological networks are vital for maintaining ecosystem services in urban regions. The impacts of climate change coupled with land-use and land cover change will bring serious challenges for maintaining ecosystem services in urban areas. Although not yet widely used in planning practices, the ecosystem services approach can provide an opportunity for land-use planning to develop ecologically sustainable urban regions. Currently, information on ecosystem services of urban regions is lacking and there is a need to improve the knowledge base for land-use planning.  相似文献   
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