Composition and dynamics of plasma in Saturn's magnetosphere     

Young DT  Berthelier JJ  Blanc M  Burch JL  Bolton S  Coates AJ  Crary FJ  Goldstein R  Grande M  Hill TW  Johnson RE  Baragiola RA  Kelha V  McComas DJ  Mursula K  Sittler EC  Svenes KR  Szegö K  Tanskanen P  Thomsen MF  Bakshi S  Barraclough BL  Bebesi Z  Delapp D  Dunlop MW  Gosling JT  Furman JD  Gilbert LK  Glenn D  Holmlund C  Illiano JM  Lewis GR  Linder DR  Maurice S  McAndrews HJ  Narheim BT  Pallier E  Reisenfeld D  Rymer AM  Smith HT  Tokar RL  Vilppola J  Zinsmeyer C 《Science (New York, N.Y.)》2005,307(5713):1262-1266

During Cassini's initial orbit, we observed a dynamic magnetosphere composed primarily of a complex mixture of water-derived atomic and molecular ions. We have identified four distinct regions characterized by differences in both bulk plasma properties and ion composition. Protons are the dominant species outside about 9 RS (where RS is the radial distance from the center of Saturn), whereas inside, the plasma consists primarily of a corotating comet-like mix of water-derived ions with approximately 3% N+. Over the A and B rings, we found an ionosphere in which O2+ and O+ are dominant, which suggests the possible existence of a layer of O2 gas similar to the atmospheres of Europa and Ganymede.  相似文献   

Staphylococcus aureus seroproteomes discriminate ruminant isolates causing mild or severe mastitis     

Le Maréchal C  Jardin J  Jan G  Even S  Pulido C  Guibert JM  Hernandez D  François P  Schrenzel J  Demon D  Meyer E  Berkova N  Thiéry R  Vautor E  Le Loir Y 《Veterinary research》2011,42(1):35

ABSTRACT: Staphylococcus aureus is a major cause of mastitis in ruminants. In ewe mastitis, symptoms range from subclinical to gangrenous mastitis. S. aureus factors or host-factors contributing to the different outcomes are not completely elucidated. In this study, experimental mastitis was induced on primiparous ewes using two S. aureus strains, isolated from gangrenous (strain O11) or subclinical (strain O46) mastitis. Strains induced drastically distinct clinical symptoms when tested in ewe and mice experimental mastitis. Notably, they reproduced mild (O46) or severe (O11) mastitis in ewes. Ewe sera were used to identify staphylococcal immunoreactive proteins commonly or differentially produced during infections of variable severity and to define core and accessory seroproteomes. Such SERological Proteome Analysis (SERPA) allowed the identification of 89 immunoreactive proteins, of which only 52 (58.4%) were previously identified as immunogenic proteins in other staphylococcal infections. Among the 89 proteins identified, 74 appear to constitute the core seroproteome. Among the 15 remaining proteins defining the accessory seroproteome, 12 were specific for strain O11, 3 were specific for O46. Distribution of one protein specific for each mastitis severity was investigated in ten other strains isolated from subclinical or clinical mastitis. We report here for the first time the identification of staphylococcal immunogenic proteins common or specific to S. aureus strains responsible for mild or severe mastitis. These findings open avenues in S. aureus mastitis studies as some of these proteins, expressed in vivo, are likely to account for the success of S. aureus as a pathogen of the ruminant mammary gland.  相似文献   

Pathogenicity and reproductive fitness of <Emphasis Type="Italic">Pratylenchus coffeae</Emphasis> and <Emphasis Type="Italic">Radopholus arabocoffeae</Emphasis> on Arabica coffee seedlings (<Emphasis Type="Italic">Coffea arabica</Emphasis> cv. Catimor) in Vietnam     

Phap Q. Trinh  Wim M. L. Wesemael  Sy T. T. Nguyen  Chau N. Nguyen  Maurice Moens 《European journal of plant pathology / European Foundation for Plant Pathology》2011,130(1):45-57

The pathogenicity and reproductive fitness of Pratylenchus coffeae and Radopholus arabocoffeae from Vietnam on coffee (Coffea arabica) seedlings cv. Catimor were evaluated in greenhouse experiments. The effect of initial population densities (Pi = 0, 1, 2, 4, 8, 16, 32, 64, 128, and 256 nematodes per cm³ soil) was studied for both species at different days after inoculation (dai). The data were adjusted to the Seinhorst damage model Y = m + (1-m).z^Pi-T. Tolerance limit (T) for P. coffeae was zero for the height and the diameter of the coffee plants. For the diameter, the T-value for R. arabocoffeae was 25.6 for 30 and 60 dai and 12.8 for 90 and 120 dai. After 4 months T was zero. The low tolerance limits indicate that Arabica coffee is highly intolerant to both nematode species. At the end of the experiment (180 dai), all plants were infected and most were dead when inoculated with R. arabocoffeae at initial densities of 32, 64, 128 and 256 nematodes/cm³ soil. For P. coffeae plant death was already observed at the lowest inoculation densities. Growth of coffee was reduced at all inoculation levels for both species. Pratylenchus coffeae and R. arabocoffeae caused intense darkening of the roots, leaf chlorosis and a strong reduction of root and shoot growth. It was observed that P. coffeae mainly destroyed lateral roots rather than tap roots, whereas R. arabocoffeae reduced tap root length rather than the lateral roots. At the lowest inoculum densities, the reproduction factor of P. coffeae was 2.38 and 2.01 for R. arabocoffeae, indicating that arabica coffee is a host for both species. Plant growth as expressed by shoot height and shoot and root weight measured 60 dai was negatively correlated with nematode (both species) density as expressed by the geometric mean of nematode numbers at 30 and 60 dai.  相似文献   

Physics. Superfluid helium-3 has a metallic partner     

Rice M 《Science (New York, N.Y.)》2004,306(5699):1142-1143

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Instructive role of Wnt/beta-catenin in sensory fate specification in neural crest stem cells     

Lee HY  Kléber M  Hari L  Brault V  Suter U  Taketo MM  Kemler R  Sommer L 《Science (New York, N.Y.)》2004,303(5660):1020-1023

Wnt signaling has recently emerged as a key factor in controlling stem cell expansion. In contrast, we show here that Wnt/beta-catenin signal activation in emigrating neural crest stem cells (NCSCs) has little effect on the population size and instead regulates fate decisions. Sustained beta-catenin activity in neural crest cells promotes the formation of sensory neural cells in vivo at the expense of virtually all other neural crest derivatives. Moreover, Wnt1 is able to instruct early NCSCs (eNCSCs) to adopt a sensory neuronal fate in a beta-catenin-dependent manner. Thus, the role of Wnt/beta-catenin in stem cells is cell-type dependent.  相似文献   

Domain architecture of pyruvate carboxylase, a biotin-dependent multifunctional enzyme     

St Maurice M  Reinhardt L  Surinya KH  Attwood PV  Wallace JC  Cleland WW  Rayment I 《Science (New York, N.Y.)》2007,317(5841):1076-1079

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应用双倍PCR技术快速检测大豆胞囊线虫   总被引：1，自引：0，他引：1  

彭德良  S A Subbotin  Maurice Moens  唐文华 《沈阳农业大学学报》2001,32(3):216-217

描述了一种基于双倍PCR技术，用种特异性引物快速鉴定大一啼胞囊线虫方法。应用两组引物扩增胞囊线虫的rDNA。第一组引物含有2个通用引物D3A和D3B，用于扩增大亚基核糖体基因（28S rDNAgene）的D3扩展区；第二组引物包括大豆胞囊线虫特异性引物GlyF1和一个通用引物rDNA2，用于扩增ITS2区的片断和部分28S基因，用此双倍PCR扩增技术检测了来自中国、俄罗斯、美国和巴西的53个大豆胞囊线虫群体，结果表明，用两组引物进行双倍PCR扩增，所有53个大豆胞囊线虫群体都产生两个明显的片断（181bp and 345 bp），其中181bp片断是SCN特异性引物GlyF1和rDNA2扩增出大豆胞囊线虫中特异性片断，在所测试的其它胞囊线虫群体，仅仅扩增出345bp的片断，而不能扩增出大豆胞囊线虫的特异性片断，用该项技术能从大豆胞囊经一虫的胞囊或单头二龄幼虫的微量DNA中，扩增出大豆胞囊线虫的特异性片断，该技术的敏感性达到单条二龄幼虫的水平。  相似文献   

Proteins of seminal fluid and spermatozoa in the trout (Oncorhynchus mykiss): Partial characterization and variations     

M. Loir  C. Labbé  G. Maisse  A. Pinson  G. Boulard  B. Mourot  F. Chambeyron 《Fish physiology and biochemistry》1990,8(6):485-495

The protein composition of seminal fluid, blood serum, sperm plasma membrane and flagellum of rainbow trout were analysed by SDS-polyacrylamide gel electrophoresis. Immunological identity between proteins of the 2 fluids and sperm components was studied using crossed immunoelectrophoresis, rocket immunoelectrophoresis and immunoblotting. Results indicate that many seminal proteins are antigenically-related to serum proteins, proteins of sperm origin are present in seminal fluid in varying amounts, depending on the animals and sampling time, and several serum-like seminal proteins are bound to spermatozoa. Lipoproteins were isolated from seminal fluid (mean level: 33 μg/ml) and characterized. They were identified as being HDL-like lipoproteins. A possible physiological role is proposed for these seminal lipoproteins.  相似文献   

On the role of algae in larviculture of Macrobrachium rosenbergii     

Dan Cohen  Aliza Finkel  Maurice Sussman 《Aquaculture (Amsterdam, Netherlands)》1976,8(3):199-207

The possible roles of algae (i.e. “green water”) in facilitating Macrobrachium rosenbergii larviculture have been investigated.Larvae were incubated with ¹⁴C uniformly labeled Tetraselmis sp. and Phaeodactylum sp. No counts were incorporated by the larvae indicating that negligible quantities of algal cell material are ingested directly. In contrast, Artemia nauplii assimilated and digested appreciable quantities of algae under similar conditions.The algae rapidly removed ammonia that had been added to the larviculture medium even starting at levels toxic to the larvae (0.6 ppm). However, very high densities of Artemia (20/ml) caused ammonia accumulation even in the presence of the algae due to their own increased metabolic rate when fed upon algae and due to the reduced number of assimilating algae. Removal of the Artemia under these conditions was followed by rapid disappearance of the ammonia.The beneficial effects of Tilapia as a larviculture associate, reported elsewhere, was observed only in the presence of algae. Larval mortality actually increased in water that had supported the growth of Tilapia if algae were not present.It is concluded that algae facilitate the growth of Macrobrachium larvae only indirectly by removing toxic material, notably ammonia, from the medium. Under conditions where the Artemia are grown before contact with the Macrobrachium larvae and where other means of ammonia removal are employed, larval growth and development are not affected by the presence of algae and the latter can be dispensed with.  相似文献   

Agricultural waste amendments improve inundation treatment of soil contaminated with potato cyst nematodes,Globodera rostochiensis and G. pallida     

Negin Ebrahimi  Nicole Viaene  Johan Aerts  Jane Debode  Maurice Moens 《European journal of plant pathology / European Foundation for Plant Pathology》2016,145(4):755-775

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