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171.
IL-10 is an anti-inflammatory cytokine that suppresses NO synthase (NOS) and production of NO; its lack may promote NO production and alterations in cytokines modulated by NO with allergic airway inflammation (AI), such as IL-18 and IL-4. Therefore, we induced AI in IL-10 knockout ((-/-)) and IL-10-sufficient C57BL/6 (C57) mice with inhaled OVA and measured airway NO production, as exhaled NO (E(NO)) and bronchoalveolar lavage fluid nitrite levels. E(NO) and nitrite levels were elevated significantly in naive IL-10(-/-) mice as compared with C57 mice. With AI, E(NO) and nitrite levels increased in C57 mice and decreased in IL-10(-/-) mice. IL-18 production fell with both AI and addition of S-nitroso-N-acetyl-d,l-penicillamine (a NO donor) but was not significantly increased by chemical NOS inhibition by l-N(5)-(1-iminoethyl)-ornithine. IL-4 AI was increased significantly (up to 10-fold greater) in the absence of IL-10 but was reduced significantly with chemical inhibition of NOS. Airway responsiveness was lower in IL-10(-/-) mice and was associated with alteration in production of NO and IL-4. Thus, IL-4 production was increased, and likely decreased NO production, in a way not predicted by the absence of IL-10. Inhibition of IL-4 production, with inhibition of NOS in the absence of IL-10, demonstrated the importance of a NO and IL-4 feedback mechanism regulating this interaction.  相似文献   
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173.
Changes in global climate have raised concerns about the emergence and resurgence of infectious diseases. Vibrio cholerae is a reemerging pathogen that proliferates and is transported on marine particles. Patterns of cholera outbreaks correlate with sea surface temperature increases, but the underlying mechanisms for rapid proliferation of V. cholerae during ocean warming events have yet to be fully elucidated. In this study, we tested the hypothesis that autochthonous marine bacteria impede the spread of V. cholerae in the marine environment. It was found that some marine bacteria are capable of inhibiting the growth of V. cholerae on surfaces and that bacterial isolates derived from pelagic particles show a greater frequency of V. cholerae inhibition than free-living bacteria. Vibrio cholerae was less susceptible to antagonism at higher temperatures, such as those measured during El Niño-Southern Oscilliation and monsoonal events. Using a model system employing green fluorescent protein-labeled bacteria, we found that marine bacteria can directly inhibit V. cholerae colonization of particles. The mechanism of inhibition in our model system was linked to the biosynthesis of andrimid, an antibacterial agent. Antibiotic production by the model antagonistic strain decreased at higher temperatures, thereby explaining the increased competitiveness of V. cholerae under warmer conditions. These findings suggest that bacterium-bacterium antagonism is a contributing mechanism in regulating the proliferation of V. cholerae on marine particles.  相似文献   
174.
A new brachiopod species, Westonia mardini, from the Furongian of Turkey and a new occurrence of Westonia urbiona from the Cambrian Series 3 of Iberian Peninsula are reported. These new finds of ‘westoniids’ collected in Gondwana allow the discussion of the functional morphology of their terrace ridges. This structure enabled an effective and rapid reburrowing and allowed the occupation of the shallow marine unstable sands and silts in the shoreface environments. This burrowing mechanism, with their pedicle directed downwards, was unknown before the Cambrian Series 2 and was abandoned chiefly in the Early Ordovician. Here we also review the distribution of ‘westoniids’ in space and time to analyse the diversification, decline and replacement of this important group of brachiopods. They became a significant part of the semi-infaunal marine associations beginning with the Cambrian Series 2 and proliferated in shallow arenaceous shelves during the Cambrian Series 3 and during the Furongian in most palaeocontinents. The acme of ‘Westoniid’ obolids associations was in the Furongian, but locally relict associations were present in high-latitude Gondwana until the Tremadocian. Decline of westoniid associations began during the Tremadocian, being replaced by very diverse smooth-shelled obolid associations with a novel burrowing mechanism and deeper lifestyle.

http://zoobank.org/urn:lsid:zoobank.org:act:4D74A740-34FD-4E3A-89BA-F80128800C0E  相似文献   

175.
Regino Zamora 《Oecologia》1990,84(3):376-379
Summary The taxonomic composition and size of arthropods captured by Pinguicula nevadense, an endemic carnivorous plant of the high-mountain zone of the Sierra Nevada (southern Spain), are analysed. The actual prey of P. nevadense and the available arthropods trapped by mimic-traps are compared, in order to identify the capture constraints of the plant. The results show that P. nevadense captures various arthropod taxa. Winged insects, especially Nematocera, make up the main component of the diet. The range of prey sizes in all P. nevadense populations studied is similar. The taxonomic composition of arthropods trapped by the mimic-traps is similar to that of the actual prey of P. nevadense. However, the plant captures prey only below a specific size threshold. These size constraints appear to be the principal factor determining the actual prey of this carnivorous plant.  相似文献   
176.
The syntheses and reactions of two epoxyketoacids (methyl (Z)-9,10-epoxy-13-oxo-(E)-11-octadecenoate (IV) and methyl (E)-9,10-epoxy-13-oxo-(E)-11-octadecenoate (V)) are described. The synthetic method is based on the stereoselective oxidation of linoleic acid by soybean lipoxygenase to produce the corresponding 13-hydroperoxide. Reduction of the hydroperoxide with sodium borohydride followed by oxidation, esterification and epoxidation yielded the compounds IV and V with a global yield of 14% and 3%, respectively, referred to the diasteromerically pure isolated compounds. Confirmation of the structures was carried out by reduction of the ketone group with sodium borohydride and by the opening of the oxirane ring with methanolic boron trifluoride. The reduction of compounds IV and V with hydrogen mainly yielded the tetrahydrofuranoid fatty acid, methyl 10,13-epoxyoctadecanoate. This reaction may be considered a new procedure to obtain tetrahydrofuranoid fatty acids.  相似文献   
177.
The construction industry is an important contributor to urban economic development and consumes large volumes of building material that are stocked in cities over long periods. Those stocked spaces store valuable materials that may be available for recovery in the future. Thus quantifying the urban building stock is important for managing construction materials across the building life cycle. This article develops a new approach to urban building material stock analysis (MSA) using land‐use heuristics. Our objective is to characterize buildings to understand materials stocked in place by: (1) developing, validating, and testing a new method for characterizing building stock by land‐use type and (2) quantifying building stock and determining material fractions. We conduct a spatial MSA to quantify materials within a 2.6‐square‐kilometer section of Philadelphia from 2004 to 2012. Data were collected for buildings classified by land‐use type from many sources to create maps of material stock and spatial material intensity. In the spatial MSA, the land‐use type that returned the largest footprint (by percentage) and greatest (number) of buildings were civic/institutional (42%; 147) and residential (23%; 275), respectively. The model was validated for total floor space and the absolute overall error (n = 46; 20%) in 2004 and (n = 47; 24%) in 2012. Typically, commercial and residential land‐use types returned the lowest overall error and weighted error. We present a promising alternative method for characterizing buildings in urban MSA that leverages multiple tools (geographical information systems [GIS], design codes, and building models) and test the method in historic Philadelphia.  相似文献   
178.
179.
1. The colonisation of a new habitat by a community is led by deterministic and stochastic processes at different spatio-temporal scales. Parasitic plants, such as mistletoe, represent a new habitat within forest canopy that is free to be colonised by many organisms. 2. This study investigates how ecological factors operating at forest and plant scales drive changes in both specialist (mistletoe-dwelling) and tourist (transient visitors) arthropod communities inhabiting European mistletoe, Viscum album subsp. austriacum, in a Mediterranean pine forest. The influence of elevation along a broad elevational gradient was tested by sampling arthropod communities dwelling in mistletoe plants and host pine branches and the effects of mistletoe plant size, distances to other mistletoes, and temporal variation in arthropod assemblages inhabiting mistletoes. 3. The diversity of the specialist community remained constant along the elevational gradient and over the summer period, while the tourist and pine-dwelling arthropod communities showed species turnover. Larger mistletoes were occupied by more species and individuals, whereas more isolated mistletoes presented the same equilibrium point as the more aggregated ones. Thus, mistletoe size is key to the composition of the arthropod community. 4. In conclusion, this study's findings indicate contrasting assembly rules for specialised and tourist arthropod communities associated with mistletoe. The specialist community was highly stable and followed a deterministic trophic sequence of colonisation as the assemblage rule: first, colonisation by the main specialist herbivore, Cacopsylla visci, and, second, by its predator Anthocoris visci. Meanwhile, the tourist community, being a subset of the arthropod assemblage of the pine, acts independent of mistletoe presence.  相似文献   
180.
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