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This review essay of Across Borders: Beadwork in Iroquois Life focuses on the display of beadwork as a cultural practice that has evolved significantly throughout its history while remaining central to Iroquois identity. The exhibition draws on historical documentation, objects, and imagery that depict the varied uses of beadwork as ritual objects, sources of income, markers of identity, and as works of art. The content and narrative for the display was developed through a broad collaboration between curators, scholars, artists, and members of two Iroquois communities. The changing and continued importance of beadwork is reflected in the adaptation of materials and styles for different forms of production and use. Across Borders places Iroquois beadwork in a broad context while concentrating on specific forms and meanings that are attached to beadwork, whether created in community gatherings or by individual artists.  相似文献   
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Davey, M. R., Mulligan, B. J., Gartland, K. M. A., Peel, E.,Sargent, A. W. and Morgan, A. J. 1987. Transformation of Solanumand Nicotiana species using an Ri plasmid vector.—J. exp.Bot. 38: 1507–1516. Five Nicotiana species (N. benthemiana, N. debneyi, N. occidentals,N. plumbaginifolia, N. tabacum) and three Solanum species (S.dulcamara, S. nigrum, S. tuberosum) were transformed by wild-typeand engineered Ri plasmids. Depending on the host plant, rootstransformed by Agrobacterium strain A4TIII with an Ri plasmidcarrying a chimaeric nopaline synthase-kanamycin resistancegene, were 3 to 40 times more resistant to kanamycin than rootstransformed by the wild-type plasmid of strain A4T. Similarly,plants regenerated from A4TIII-derived roots of N. debneyi,N. plumbaginifolia and N. tabacum were 8 to 16 times more resistantthan A4T plants, and survived at 400 µg cm3 of kanamycin.A4TIII plants of S. nigrum flowered in vitro at 600–1000µg cm3 of kanamycin. Transformed roots and most regeneratedplants synthesized Ri-speciflc opines, while DNA hybridizationconfirmed the presence of DNA homologous to that from wild-typeand engineered Ri plasmids in transformed plants of S. nigrum. Key words: Agrobacterium, Ri plasmid, transformed roots, plant regeneration, kanamycin resistance.  相似文献   
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MORGAN  J. M. 《Annals of botany》1988,62(2):193-198
Differences in osmoregulation between genotypes of wheat (Triticumaestivum L.) were identified by measuring responses of coleoptilesto water stress. Seeds were germinated in Petri dishes on germinationpads. Water stress was applied when coleoptiles were 1 cm longby either adding polyethylene glycol 6000 (20% w/w) or by removingthe lids of the dishes and allowing the pads to dry by evaporationfor a period of 2 d, or from the beginning of germination byvarying the amount of water in the germination pads. Measurementsof the water and osmotic potentials of shoots and roots (usingthermocouple psychrometers) were used to estimate turgor pressures.Wheat genotypes showed the same segregation for shoot and rootlengths and turgor pressures as they had done in previous studiesfor flag-leaf osmoregulation and yield. It was concluded thatobservations of the responses of coleoptile length to waterstress could be used in plant-breeding applications to identifydifferences in osmoregulation between genotypes of wheat. Triticum aestivum, osmoregulation, turgor maintenance, coleoptile growth, root, selection criterion  相似文献   
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CELLS from patients with G-trisomy or E-trisomy and XXY cells from patients with XY/XXY mosaic Klinefelter's syndrome are more susceptible to transformation in vitro by SV40 than are cells from normal individuals1–3. We have used triploid (69XXY) human cells to determine whether the presence of extra chromosomes per se increases susceptibility to transformation.  相似文献   
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Primary Structure of Lysozymes from Man and Goose   总被引:4,自引:0,他引:4  
The primary structure of goose egg white lysozyme seems to be distinct from that of hen egg white and human leukaemia lysozymes.  相似文献   
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Wheat and oat were grown for 20 d on a nitrate-containing solution(nitrogen-replete plants) or for the last 6 d of this periodon a nitrate-free solution (nitrogen-depleted plants). Exposureof the nitrogen-depleted plants on day 20 to nitrate-free solutionscontaining 500 mmol m–3 ammonium (96 A% 15N) resultedin a cumulative net influx of 15N-ammonium over an 8 h periodthat was appreciably greater than that of the nitrogen-repleteplants. Both the initial rate and the more restricted rate afterthe first hour were enhanced by nitrogen deprivation. In thenitrogen-replete plants, cumulative net efflux of endogenous14N-ammonium was approximately equivalent to net ammonium uptakeduring the first hour, and was essentially complete after 1–2h. Pretreating nitrogen-depleted plants for 5 h in 500 mmolm–3 15N-ammonium (99 A% 15N) resulted in root ammoniumconcentrations of 12.7?1.1 and 16.0?0.4 µmol for wheat and oat, respectively. Subsequent net efflux of 15N-ammoniumto 500 mmol m–3 exogenous 14N-ammonium exceeded theseinitial amounts within 2 h. Increasing ambient 14N-ammoniumto 5000 mmol m–3 increased net 15N-ammonium efflux suchthat net loss of the maximal original amount in the root tissuewas exceeded within 0.75 h. The data for both species indicatesubstantial reciprocal transfers of ammonium into and out ofroots of ammonium-treated plants and a significant degradationof recently synthesized products of ammonium assimilation concurrentwith ammonium assimilation. Key words: Accumulation, ammonium, efflux, oat, root, uptake, wheat  相似文献   
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  • 1 Chemical communication plays an important part in the lives of insects, and particularly in lives of those that live in groups or social organizations.
  • 2 Chemicals which are used in communication in the general sense are called semiochemicals, and there are a number of subdivisions recognized under this title.
  • 3 Pheromones are a category of semiochemicals which are used for communication between individuals of the same species.
  • 4 Pheromones are in turn subdivided into primer and releaser pheromones. The former produce a relatively long-lasting physiological change in the receiver, and the latter stimulate the receiver to some immediate behavioural response.
  • 5 Far more is known about releaser pheromones at present because they are easier to study.
  • 6 Nine categories of releaser pheromone are recognized here, used by both social and non-social insects.
  • 7 Sex pheromones are widely used to bring the sexes together for mating, and they have been extensively studied in Lepidoptera.
  • 8 Invitation pheromones, encouraging the species to feed or oviposit at an explored site, are not extensively known.
  • 9 Aggregation pheromones are designed to bring individuals together into groups which may be temporary in sub-social insects, or permanent in social insects.
  • 10 Dispersal or spacing pheromones are used by other species to reduce intraspecific competition for scarce resources.
  • 11 Alarm pheromones are a broad and sometimes unclearly defined group which communicate alarm or attack, chiefly in colonial species.
  • 12 Trail pheromones, applied to a surface by an individual, to be followed by another, are confined to Hymenoptera, Isoptera and a few Lepidoptera as far as is known.
  • 13 Territorial and home range pheromones may be widely distributed, but as yet few of them have been recognized.
  • 14 Surface and funeral pheromones are even less well known. Surface pheromones may play a large part in species or colony recognition.
  • 15 We can expect the number and complexity of pheromones to be much greater in social insects, a part of the subject which until now has received relatively less attention.
  • 16 As our understanding of the subject grows we may expect other categories to be added to this list.
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