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61.
Based on SEM examinations of some 1600 species of monocotyledons out of 61 families the characteristics of their epicuticular waxes are described in this preliminary paper and illustrated by 20 SEM micrographs. Four basic types of waxes are recognized. Two of them occur throughout the monocotyledonous and dicotyledonous orders of angiosperms; two others are of high systematic significance and restricted to particular orders of the monocotyledons: The “Convallaria-Type” is characterized by fine wax platelets with parallel orientation, forming a pattern around the stomata reminiscent of electromagnetic field lines. This type is restricted to the three liliiflorous ordersAsparagales, Liliales, andBurmanniales. The “Strelitzia-Type” is characterized by massive compound wax rodlets; it is restricted to the superordersAreciflorae, Commeliniflorae, Zingiberiflorae, plus the two liliiflorous ordersBromeliales andVelloziales. The data are compared with the classifications ofDahlgren & Clifford (1982); they tentatively indicate the exclusion ofBromeliales, Velloziales, andTyphales from theLiliiflorae. 相似文献
62.
Karl Wilhelm Heinz Comtesse Walter Pflumm 《Ethology : formerly Zeitschrift fur Tierpsychologie》1982,60(1):27-40
Different concentrations of a sucrose solution vary the courtship song and behaviour of the male yellow-bellied sunbird Nectarinia venusta- the duration of subsong, total singing duration, and the absolute number of full song phrases. With high concentrations the sunbird sings more full song phrases but less subsong during the courtship season than otherwise. The various effects are described. 相似文献
63.
Lactose carrier protein of Escherichia coli. Structure and expression of plasmids carrying the Y gene of the lac operon 总被引:53,自引:0,他引:53
R M Teather J Bramhall I Riede J K Wright M Fürst G Aichele U Wilhelm P Overath 《European journal of biochemistry》1980,108(1):223-231
The previously described hybrid plasmid pC7 which carries lacI+O+delta(Z)Y+A+ on a 12.3 X 10(6)-Mr DNA fragment [Teather et al. (1978) Mol. Gen. Genet. 159, 239-248] was partially digested with the restriction endonuclease EcoRI under conditions reducing the recognition sequence to d(A-A-T-T) and ligated to the vector pB322. lac Y-carrying inserts of various sized (Mr 1.5-4.7 X 10(6)) were obtained. Hybrid plasmid pTE18 (2300-base-pair insert) carries part of the I (repressor) gene, the promotor-operator region, part of the Z (beta-galactosidase) gene, the Y (lactose carrier) gene and part of the A (transacetylase) gene. Upon induction of pTE18-harbouring strains the Y-gene product is expressed at a nearly constant rate for several generations and accumulates to a level of 12-16% of the total cytoplasmic membrane protein. Integration into the membrane leads to active carrier as judged by binding and transport measurements. 相似文献
64.
Summary Senescence occurs in all wild strains of Podospora anserina after continued growth. This syndrome can be inhibited by a synergistic interaction of two linked genes, incoloris and vivax. Whereas the wild strain starts to become senescent after 26 d and the mutants incoloris and vivax after 42 and 66 d respectively, the double mutant shows no signs of aging after culture for more than one year. 相似文献
65.
Immunofluorescence microscopy using monospecific tubulin antibody shows that in vivo griseofulvin interferes with the expression of both cytoplasmic and spindle microtubules in tissue culture cells in a concentration-dependent manner. In mouse 3T3 cells cytoplasmic microtubules are destroyed at a griseofulvin concentration of 5 × 10?5m. At this concentration no increase of the mitotic index is observed but the cells are arrested in interphase, probably due to the destruction of cytoplasmic microtubules. Lowering the drug concentration to 10?5m allows 3T3 cells to accumulate in c-mitotic (“colchicin-mitotic”) arrest. In HeLa cells the display of spindle microtubules observed in drug-arrested cells appears similar to that seen in normal metaphase cells only at lower griseofulvin concentrations. Higher drug concentrations induce c-mitotic arrest accompanied by an increasing loss of typical metaphase tubulin structures.In vitro polymerization experiments with brain tubulin using both light-scattering and electron microscopy show that in the presence of griseofulvin tubulin can aggregate rapidly in the cold. This behaviour is not found in the absence of the drug. Thus both in vivo and in vitro experiments show that griseofulvin, like other c-mitotic drugs, acts at the level of tubulin polymerization and that its effects are concentration dependent. 相似文献
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Wilhelm Roux 《Development genes and evolution》1894,1(1):43-68
Ohne ZusammenfassungNr. VIII der fortlaufenden, in verschiedene Zeitschriften vertheilten Serie von des Verfassers »Beiträgen zur Entwickelungsmechanik des Embryo«. 相似文献
70.
Wilhelm Snksdorf 《Plant Systematics and Evolution》1923,72(1-5):94-95
Ohne Zusammenfassung 相似文献