Not normal littermates     

Lane PW 《Science (New York, N.Y.)》1982,218(4577):1070

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Mathematics     

Lane SM 《Science (New York, N.Y.)》1980,209(4452):104-110

Current research in mathematics involves a wide variety of interlocking ideas, old and new. For example, results about the curves and surfaces defined by polynomial equations, as in algebraic geometry, appear in the study of solitary waves and also in the gauge theories in physics. Centuries-old problems in number theory have been solved, while others have been revealed as insoluble. The classification of all finite simple groups is nearly achieved (and the full treatment will be voluminous); the representation of groups aids in their application to the study of symmetry. These developments, and many others, attest to the vitality of mathematics.  相似文献   

Regulation of cytokine receptors by Golgi N-glycan processing and endocytosis     

Partridge EA  Le Roy C  Di Guglielmo GM  Pawling J  Cheung P  Granovsky M  Nabi IR  Wrana JL  Dennis JW 《Science (New York, N.Y.)》2004,306(5693):120-124

The Golgi enzyme beta1,6 N-acetylglucosaminyltransferase V (Mgat5) is up-regulated in carcinomas and promotes the substitution of N-glycan with poly N-acetyllactosamine, the preferred ligand for galectin-3 (Gal-3). Here, we report that expression of Mgat5 sensitized mouse cells to multiple cytokines. Gal-3 cross-linked Mgat5-modified N-glycans on epidermal growth factor and transforming growth factor-beta receptors at the cell surface and delayed their removal by constitutive endocytosis. Mgat5 expression in mammary carcinoma was rate limiting for cytokine signaling and consequently for epithelial-mesenchymal transition, cell motility, and tumor metastasis. Mgat5 also promoted cytokine-mediated leukocyte signaling, phagocytosis, and extravasation in vivo. Thus, conditional regulation of N-glycan processing drives synchronous modification of cytokine receptors, which balances their surface retention against loss via endocytosis.  相似文献   

Trans-endocytosis of CD80 and CD86: a molecular basis for the cell-extrinsic function of CTLA-4   总被引：1，自引：0，他引：1  

Qureshi OS  Zheng Y  Nakamura K  Attridge K  Manzotti C  Schmidt EM  Baker J  Jeffery LE  Kaur S  Briggs Z  Hou TZ  Futter CE  Anderson G  Walker LS  Sansom DM 《Science (New York, N.Y.)》2011,332(6029):600-603

Cytotoxic T lymphocyte antigen 4 (CTLA-4) is an essential negative regulator of T cell immune responses whose mechanism of action is the subject of debate. CTLA-4 shares two ligands (CD80 and CD86) with a stimulatory receptor, CD28. Here, we show that CTLA-4 can capture its ligands from opposing cells by a process of trans-endocytosis. After removal, these costimulatory ligands are degraded inside CTLA-4-expressing cells, resulting in impaired costimulation via CD28. Acquisition of CD86 from antigen-presenting cells is stimulated by T cell receptor engagement and observed in vitro and in vivo. These data reveal a mechanism of immune regulation in which CTLA-4 acts as an effector molecule to inhibit CD28 costimulation by the cell-extrinsic depletion of ligands, accounting for many of the known features of the CD28-CTLA-4 system.  相似文献   

The genome of the diatom Thalassiosira pseudonana: ecology, evolution, and metabolism     

Armbrust EV  Berges JA  Bowler C  Green BR  Martinez D  Putnam NH  Zhou S  Allen AE  Apt KE  Bechner M  Brzezinski MA  Chaal BK  Chiovitti A  Davis AK  Demarest MS  Detter JC  Glavina T  Goodstein D  Hadi MZ  Hellsten U  Hildebrand M  Jenkins BD  Jurka J  Kapitonov VV  Kröger N  Lau WW  Lane TW  Larimer FW  Lippmeier JC  Lucas S  Medina M  Montsant A  Obornik M  Parker MS  Palenik B  Pazour GJ  Richardson PM  Rynearson TA  Saito MA  Schwartz DC  Thamatrakoln K  Valentin K  Vardi A  Wilkerson FP  Rokhsar DS 《Science (New York, N.Y.)》2004,306(5693):79-86

Diatoms are unicellular algae with plastids acquired by secondary endosymbiosis. They are responsible for approximately 20% of global carbon fixation. We report the 34 million-base pair draft nuclear genome of the marine diatom Thalassiosira pseudonana and its 129 thousand-base pair plastid and 44 thousand-base pair mitochondrial genomes. Sequence and optical restriction mapping revealed 24 diploid nuclear chromosomes. We identified novel genes for silicic acid transport and formation of silica-based cell walls, high-affinity iron uptake, biosynthetic enzymes for several types of polyunsaturated fatty acids, use of a range of nitrogenous compounds, and a complete urea cycle, all attributes that allow diatoms to prosper in aquatic environments.  相似文献   

Using Participatory Workshops to Integrate State-and-Transition Models Created With Local Knowledge and Ecological Data     

Corrine Noel Knapp  Maria Fernandez-Gimenez  Emily Kachergis  Aleta Rudeen 《Strength and Conditioning Journal》2011,64(2):158-170

State-and-transition models (STMs) depict current understanding of vegetation dynamics and are being created for most ecological sites in the United States. Model creation is challenging due to inadequate long-term data, and most STMs rely on expert knowledge. There has been little systematic documentation of how different types of knowledge have been integrated in STMs, or what these distinct knowledge sources offer. We report on a series of participatory workshops where stakeholders helped to integrate STMs developed for the same region using local knowledge and ecological field data. With this exploratory project, we seek to understand what kinds of information local knowledge and ecological field data can provide to STMs, assess workshops as a method of integrating knowledge and evaluate how different stakeholders perceive models created with different types of knowledge. Our analysis is based on meeting notes, comments on draft models, and workshop evaluation questionnaires. We conclude that local knowledge and ecological data can complement one another, providing different types of information at different spatial and temporal scales. Participants reported that the workshop increased their knowledge of STMs and vegetation dynamics, suggesting that engaging potential model users in developing STMs is an effective outreach and education approach. Agency representatives and ranchers expressed the value of both the local knowledge and data-driven models. Agency participants were likely to critique or add components based on monitoring data or prior research, and ranchers were more likely to add states and transitions based on personal experience. As STM development continues, it is critical that range professionals think systematically about what different forms of data might contribute to model development, how we can best integrate existing knowledge and data to create credible and useful models, and how to validate the resulting STMs.  相似文献   

Microbiota accompanying different arbuscular mycorrhizal fungal isolates influence soil aggregation     

Matthias C. Rillig  Emily R. Lutgen  Philip W. Ramsey  John N. Klironomos  James E. Gannon 《Pedobiologia》2005,49(3):43

Arbuscular mycorrhizal fungi (AMF) are key components of ecosystems through their influence on plant communities and ecosystem processes. A major source of information regarding the importance of AMF species richness on process rates are mesocosm experiments using different levels of diversity of AMF as provided by single-species cultures of AMF. Since AMF inocula are generally made available in the form of non-sterile pot culture material, it is possible that AMF symbiosis-associated microbiota are at least partially responsible for some effects hitherto directly attributed to the AMF mycelium. Here, we provide evidence that microbiota associated with single-species cultures of AMF (after long-term pot culture enrichment of 7–8 years) can strongly affect the ecosystem process of soil aggregation. This effect occurred in an AMF isolate specific manner, but in the absence of live and active AMF mycelium. We additionally documented large differences in microbiota communities associated with the different AMF inocula (using PLFA analyses), suggesting that these differences were at least partly responsible for the observed changes in soil aggregation. This result points to AMF–microbiota interactions as a largely unexplored mechanism underlying soil aggregation (and potentially other ecosystem processes). We suggest that a reinterpretation of previous experiments using greenhouse-derived AMF cultures may be necessary, and the need to consider AMF symbiosis-associated microbiota in mechanistic studies of AMF and mycorrhizae in general is emphasized.  相似文献   

Deactivation of the biological activity of paraquat in the soil environment: a review of long-term environmental fate   总被引：3，自引：0，他引：3  

Roberts TR  Dyson JS  Lane MC 《Journal of agricultural and food chemistry》2002,50(13):3623-3631

During the many years of paraquat usage, wide ranges of investigations of its environmental impact have been conducted. Much of this information has been published, but key, long-term field studies have not previously been presented and assessed. The purpose of this review is to bring together and appraise this information. Due to the nature of paraquat residues in soils, the major part (some 99.99%) of a paraquat application that reaches the soil within the typical Good Agricultural Practice (GAP) is strongly adsorbed to soils of a wide variety of textures. This is in equilibrium with an extremely low concentration in soil solution. However, the paraquat in soil solution is intrinsically biodegradable, being rapidly and completely mineralized by soil microorganisms. The deactivation of the biological activity of paraquat in soils, due to sorption, has been investigated thoroughly and systematically. It is recognized that the determination of total soil residues by severe extraction procedures provides no insight into the amount of paraquat biologically available in soil. Consequently, the key assay developed for this purpose, namely, the strong adsorption capacity-wheat bioassay (SAC-WB) method, has proved to be valuable for determination of the adsorption capacity relevant to paraquat for any particular soil. This method has been validated in the field with a series of long-term (>10 years) trials in different regions of the world. These trials have also shown that, following repeated applications of very high levels of paraquat in the field, residues not only reach a plateau but also subsequently decline. This demonstrates that the known biodegradation of paraquat in soil pore water plays an important role in field dissipation. The biological effects of paraquat in the field have been assessed under unrealistically high treatment regimes. These trials have demonstrated that the continued use of paraquat under GAP conditions will have no detrimental effects on either crops or soil-dwelling flora and fauna. Any such effects can occur only under extreme use conditions (above the SAC-WB), which do not arise in normal agricultural practice.  相似文献   

Action of dexamethasone in an equine model of acute non-immune inflammation     

P J Lane  P Lees  J Fink-Gremmels 《Research in veterinary science》1990,48(1):87-95

In a crossover study in seven New Forest ponies the actions of dexamethasone, at a dose rate of 0.06 mg kg-1 administered intravenously, were compared with those of a placebo treatment. Dexamethasone exerted expected effects on plasma and inflammatory exudate concentrations of cortisol and on blood glucose concentration and circulating leucocyte numbers, but it failed to affect exudate concentrations of the eicosanoids, prostaglandin E2, thromboxane B2, 6-keto-PGF1 alpha and leukotriene B4. These findings do not support the hypothesis that the anti-inflammatory actions of dexamethasone in the horse are mediated by inhibition of phospholipase A2.  相似文献   

Comparison of Prepared Feed Versus Natural Food Ingestion Between Pond-Cultured Bluegill and Hybrid Sunfish     

Ryan L.  Lane Joseph E.  Morris 《Journal of the World Aquaculture Society》2002,33(4):517-519

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