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SYNOPSIS A method is described for the axenic mass cultivation of Paramecium tetraurelia strains 51s and 299s. the ciliate is grown in an enriched axenic medium developed by Soldo, Godoy & van Wagtendonk. Under continuous shaking on a rotary shaker, cultures were grown in one-liter Erlenmeyer flasks with 330 ml medium yield cell densities of 32,000 cell/ml and 20,000 cells/ml for strains 299s and 51s respectively. Doubling time is considerably shorter under these conditions than in the conventional static cultures. A 20-liter airlift bioreactor is described in detail which can be used successfully to otain up to 100 g wet weight of Paramecium in a single run; in this reactor the cell density reaches 38,000 cells/ml for strain 299s. and 23,000 cells/ml for 51s. This technic should facilitate the study of minor protein components of the ciliate.  相似文献   
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An updated angiosperm classification   总被引:5,自引:0,他引:5  
DAHLGREN, C, 1989. An updated angiosperm classification. A new two-dimensional diagram, reflecting the system of classification of the angiosperms, is presented. It combines the dicotyledon diagram in G. Dahlgren (1989) and an adapted monocotyledon diagram after that in Dahlgren (1985) in a single diagram. An updated monocotyledon taxonomy is presented and the classification is appended.  相似文献   
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Sugar beet (Beta vulgaris L. cv. Monohill) were cultivated ina nutrient solution with different combinations of Ca2+ (36,180, 720 or 3560µM) and Cd2+ (0, 1, 5 or 20µM).The dry and fresh weights, the content of Ca2+ and Cd2+ , sucrose,fructose, glucose and starch in 5-week-old plants was analysedas well as the rate of [14C]-sucrose uptake in discs from 3-month-oldstorage roots. The carbohydrate metabolism was indirectly affectedby the presence of calcium or cadmium. Cadmium caused a diminisheddry weight and carbohydrate concentration. The dry weight wasunaffected by the Ca2+ level but the carbohydrate distributionbetween storage and growth processes was affected; at low Ca2+in the tissue, the growth was retarded and the level of storagecarbohydrate increased, while at high Ca2+ the opposite wasfound. The [14C]-sucrose uptake decreased in tap roots cultivatedat low Ca2+ . Long term exposure to Cd2+ also decreased thesucrose uptake in tap roots. Direct Cd2+ addition to the assaymedium, however, increased the sucrose uptake, probably at thetonoplast, while Ca2+ had no transient effect on the uptake.Cadmium increased the Ca2+ concentration in the plant, but Ca2+did not affect the net-uptake of Cd2+. Key words: Sugar beet, cadmium uptake, calcium uptake, carbohydrate formation, growth  相似文献   
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1. Different groups of specialised herbivores often exhibit highly variable responses to host plant traits and phylogeny. Gall‐forming insects and mites on willows are highly adapted to their hosts and represent one of the richest communities of gallers associated with a single genus of host plants. 2. The present study evaluated the effects of host plant secondary metabolites (salicylates, flavonoids, condensed tannins), physical traits (trichome density), nutrient content (N:C) and phylogeny on the abundance and richness of gall‐forming arthropods associated with eight willow species and Populus tremula. 3. Galler abundance was affected by N:C rather than by willow defensive traits or phylogeny, suggesting that gallers respond differently to host plant traits than to less specialised guilds, such as leaf‐chewing insects. None of the studied defensive traits had a significant effect on gall abundance. Gall morphospecies richness was correlated with the host phylogeny, mainly with the nodes representing the inner division of the willow subgenus Vetrix. This suggests that the radiation of some willow taxa could have been important for the speciation of gallers associated with willows. 4. In conclusion, it is shown that whereas willow traits, such as nutrient content, appeared to affect abundances of gallers, it is probably willow radiation that drives galler speciation.  相似文献   
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Variation in leaves and petals was studied using canonical variate and cluster analyseS. In total of 33 populations from eight islands leaf variation in laminar, floating leaves was studied in Ranunculus peltatus subsp. peltatus, subsp. baudotii and subsp. saniculifolius, and in R. Tripartitus, all of which are heterophyllous in the Aegean area. The petal data set also included the homophyllous R. Trichophyllus. The results of the analyses show that the populations are morphologically well differentiated and that petal shape has a tendency to discriminate between the populations somewhat better than leaf shape does. There was no basis for subdividing the populations into taxa on these characterS. Analyses showed that up to 70% of the variation was distributed between populations, the remainder (5–18%) being within populations.  相似文献   
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SYNOPSIS Random examination of domestic animals revealed the frequent presence of free-living amebae in their bodies. In diseased or dead cows, dogs, pigs, rabbits, pigeons, and turkeys 15 strains of amebae were found, belonging to the genera Acanthamoeba (A. polyphaga), Hartmannella (H. vermiformis) , and Vahlkampfia (V. avara, V. enterica, V. inornata). , They were usually accompanied by other infectious agents in different parts of the host bodies. Pathogenicity of 3 isolates could not be demonstrated by inoculation of laboratory animals.
Some features of the isolates differed from those previously known for members of these genera. These strains may be considered amphizoic amebae according to Page (1974).  相似文献   
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Hypochaeris salzmanniana DC. (Asteraceae, Lactuceae) is an endangered species on the Iberian Peninsula, known from only eight coastal populations. Most authors have treated it as a variety, subspecies or simply as a synonym of H. glabra L. On the basis of morphological and cytological characters, Talavera recently separated H. salzmanniana (2n = 8) from H. glabra (2n = 10). Material of H. salzmanniana, H. glabra and H. radicata was collected from Spain, Italy, Sicily and Tunisia in order to assess taxonomic status and population relationships. Amplified Fragment Length Polymorphism (AFLP) analysis revealed three well-differentiated species. A close relationship between H. salzmanniana and H. radicata is also confirmed by AFLP analysis and chromosome number (2n = 8), morphology, and rDNA localization (FISH, fluorescence in situ hybridization). Hypochaeris salzmanniana and H. radicata share three fixed diagnostic AFLP fragments out of 348 fragments scored. The population structure of H. salzmanniana reveals distinct groups in southern Spain that are separated geographically. High differentiation among a western (Conil to Zahara), an intermediate (Punta Paloma and Los Algarbes) and an eastern (Algeciras and La Línea) group may reflect ancient separation. Population sizes and genetic compatibility differ greatly among populations and can be used to explain levels of within-population genetic diversity, together with recent documented loss of habitats resulting from tourist developments. Population structures of H. radicata and H. glabra show a similar geographical patterning: strongly differentiated populations from the Betic Cordillera and from the Iberian Massif, which are separated at present by the Guadalquivir river. Geological events at the end of the Tertiary (Tortonian–Messinian Miocene) might help explain patterns of differentiation in these three species of sect. Hypochaeris. © 2004 The Linnean Society of London, Botanical Journal of the Linnean Society, 2004, 146 , 79–95.  相似文献   
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