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931.
Water permeability and composition of soluble cuticular lipids of isolated cuticular membranes from leaves of Citrus aurantium L. were investigated for 3 successive years. The average water permeability coefficient determined using 169 cuticular membranes was 1.09·10–7 cm s–1 with a standard deviation of 0.78·10–7 cm s–1. There were no significant differences in water permeability between years. Cuticular membranes are characterized by a great variability in water permeability both within and between years. Both water permeability of individual membranes and variability between membranes are shown to be determined by soluble cuticular lipids contained within the cuticular membranes. The soluble cuticular lipids of Citrus leaves are composed of fatty acids, primary alcohols, esters, and hydrocarbons. They occur in amounts of 9.84 g cm–2, which represents approx. 3% of the total mass of isolated cuticular membranes. The specific weight of cuticular membranes (365.4 g cm–1) and total amount of soluble cuticular lipids did not vary significantly between years. Significant differences were observed for the amounts and composition of the constituent classes of lipids. Six homologues comprise 86% of the fatty acids (C16; C18; C19; C21; C24; C26), 83% of the primary alcohols (C24; C26; C28; C30; C32; C34) and 88% of the esters (C36; C38; C40; C41; C42; C44). Eleven major homologues amount only to 62% of the total hydrocarbons (C16; C17; C18; C20; C26; C27; C29; C30; C31; C32; C33). Variability in the composition of soluble cuticular lipids between years was much smaller than variability of water permeability and, therefore, no relation between composition of soluble cuticular lipids and water permeability could be found. It is suggested that this may be due to the fact that the lipid composition observed represents the averages of 20 to 30 membranes analyzed so that differences between individual membranes may have been leveled out.Abbreviations CM
cuticular membranes
- MX
polymer matrix
- Pd
permeability coefficient for diffusion of water
- SCL
soluble cuticular lipids
- MES
morpholinoethane sulphonic acid 相似文献
932.
Summary The growth of strains of fibroblasts derived from patients with neurofibromatosis (NF) was compared with that of strains from appropriate controls in culture medium containing 1% or 15% fetal calf serum. The means of the ratios of final to initial cell numbers do not differ significantly between NF strains and control strains. Weakly significant differences are, however, obtained after conversion of the results to mean numbers of cell population doublings, the NF strains showing the higher numbers. The ratios of final to initial amounts of protein also differ significantly under both sets of growth conditions. High growth parameters occur significantly more frequently among our smaple of 11 NF strains than among our sample of 13 control strains. The possibility of the expression of the NF genotype(s) on the level of the cultured fibroblast-like cells and the possible causes of the large ranges of inter-and intra-individual variations of the results are discussed. 相似文献
933.
934.
Stanley A. Robrish Claes-Göran Emilson Christopher W. Kemp Doreen Eberlein William H. Bowen 《Current microbiology》1981,5(6):343-347
The effects of three antimicrobial agents on smooth surface dental plaque in monkeys were assessed using a plaque index, bacterial viable count, and adenine nucleotide analysis. The effects of the agents were revealed equally well when, viability was assayed by extractable adenosine triphosphate (ATP) or conventional viable cell counts. A persistent effect of one of the agents was revealed by both viable count and extractable ATP. These interpretations were supported by calculations of adenylate energy charge from the adenine nucleotide content of the smooth surface dental plaque samples. 相似文献
935.
Arthopyrenia endobrya from Southern Brazil is illustrated and described as a new species of lichens. The thallus is composed of filamentous green algae loosely surrounded by fungal hyphae. Both symbionts grow endophytically within the leaf cells of two species ofLejeuneaceae (Hepaticae). The algae and hyphae penetrate the cell walls of the host by means of fine perforations. The ascocarps develop between the leaves and perforate them with their apical region. The classification as a member of the genusArthopyrenia is preliminary. 相似文献
936.
937.
Summary Light and dark adaptations were studied in the eye of Squilla mantis. Light adaptation is characterized by (1) a proximal shift of the distal pigment sheath (DPS) surrounding the proximal portion of the crystalline cone above its zone of contact with the rhabdom; (2) flattening of the distal pigment sheath; (3) lengthening of the crystalline cone correlated with shortening of the rhabdom; (4) a migration of screening pigment granules in retinula cells in the protoplasmic bridges crossing the perirhabdomal space. In animals kept in constant darkness, longitudinal displacements of the distal pigment sheath were found to be subject to a circadian rhythm characterized by a maximal light adaptation state at about 5 p.m. and a minimal one at 5 a.m. Screening pigment granule translocation in retinula cells does not show such rhythmic activity.Abbreviations a, b
maximal incidence angles in L.A., and D.A., respectively
- Cc
crystalline cone
- Dps
distal pigment sheath
- I
extreme incident light beam
- Prs
perirhabdomal space
- Rh
rhabdom
- Rp
reflecting pigment
This research has been supported by grant 3.012-76 of the Swiss National Science Foundation 相似文献
938.
Twelve indole alkaloids belonging to the Ajmaline-, Sarpagine-, Yohimbine-, and Heteroyohimbine-type have been isolated and identified from cell suspension cultures of Rauwolfia serpentina. Ten of the alkaloids were found for the first time in cultured R. serpentina cells. The yield of the main alkaloid vomilenine was 51 times more than that of differentiated plants. Crude enzymes isolated from this cell suspension culture completely metabolize the biogenetic precursor strictosidine under formation of several alkaloidal compounds. 相似文献
939.
C. M. van der Loos A. J. van Breda A. E. F. H. Meijer A. C. Jöbsis 《Histochemistry and cell biology》1981,73(2):161-164
Summary Polyacrylamide gel-electrophoresis was performed with an extract from cultivated skin fibroblasts. Arylsulphatase activity is measured and visualised using the biochemical substrate dehydroepiandrosterone sulphate and the histochemical substrate 6-bromo-2-naphthyl sulphate respectively. The histochemical substrate was hydrolysed at Rf=0.49 and 0.58 while the biochemical substrate was hydrolysed only at 0.49. We conclude that two different microsomal arylsulphatases exist: a sulphatase able to hydrolyse steroid sulphatases (Rf=0.49) and one unable to hydrolyse steroid sulphatases (Rf=0.58). In consequence it is recommended to carry out an electrophoresis experiment after the histochemical investigation, in order to discriminate between these two types of sulphatase. 相似文献
940.
Jørn Erik Bjørndalen 《Nordic Journal of Botany》1981,1(5):665-670
The basiphilous pine forests in southern Telemark, SE Norway, have previously been classified according to the ordinary phytosociological methods of the Braun—Blanquet system. The same material was later treated by numerical analysis, i.e., TABORD—classification and the ordination technique 'reciprocal averaging'. No significant differences were found between the numerical and the non—numerical classification except for the classification of some transitional communities. Ordination by 'reciprocal averaging' gave a useful complement to the TABORD classification, and re—leves and species were distributed along interpretable gradients (i.e., along a dry—wet gradient and along a gradient from forest—rim conditions to forest conditions). 相似文献