ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

X
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    Electronic Resource
    Electronic Resource
    Synthesis of 3,4-dihydro-3,3-dimethyl-1(2H)-acridinone (1995)
    Springer
    Journal of chemical crystallography 25 (1995), S. 201-203 
    Details
    ISSN: 1572-8854
    Keywords: Acridinone ; alzheimer ; dimedone
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Physics
    Notes: Abstract The acridinone derivative 3,4-dihydro-3,3-dimethyl-1(2H)-acridinone (4) has been prepared in a two step fashion and the molecular structure confirmed by X-ray diffraction. Compound4 crystallizes in the space group P2l/n witha=6.022(2),b=21.111(2),c=9.604(2) Å, β=99.97(2)°, andZ=4. The single crystal analysis showed the acridinone tricyclic ring is virtually planar except in the gem-dimethyl position of C(3) which presented a half-chair conformation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01666107
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    Effect of temperature and food concentration in two species of littoral rotifers (1998)
    Springer
    Hydrobiologia 387-388 (1998), S. 341-348 
    Details
    ISSN: 1573-5117
    Keywords: Lecanidae ; life-table ; mortality ; reproduction rate ; survivorship
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract We performed life-table experiments with two species of the littoral rotifers Lecane luna (O.F. Müller, 1776) and Lecane quadridentata (Ehrenberg, 1832). Three different temperatures (20, 25 and 30°C) and food concentrations of Nannochloris oculata (1×107, 5×106, and 1×106 cells ml-1) were investigated. We found important differences between both species in all the treatments regarding offspring sizes, hatching percentages, life span and reproductive rates. Our data on hatching percentages of asexual eggs suggested that the optimal temperature for both species is in the 20–25°C range. On the other hand, reproductive data placed the optimal temperature near 25°C. This information can be used to develop aquatic toxicology tests with littoral species.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1017099906853
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    Preparation, spectral studies, and X-ray crystal structures of (16S, 17R, 20S)-3-oxo-16-hydroxy-25-nor-lanostan-24-oic lactone (II) and (16S, 17R, 20S)-4,16-dihydroxy-25-nor-3,4-seco-lanostan-3,24-dioic acid dilactone (III) (1995)
    Springer
    Journal of chemical crystallography 25 (1995), S. 331-337 
    Details
    ISSN: 1572-8854
    Keywords: Guayule ; Parthenium ; triterpenes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Physics
    Notes: Abstract The crystal and molecular structures of the title compounds have been determined by direct methods, and refined to a finalR of 0.059 forII and 0.046 forIII. Both molecules crystallize in space group P212121. The cell dimensions forII area=10.096(5),b=11.255(3),c=20.300(7) Å;Z=4,D x=1.188 g cm−3, μ(MoKα)=0.70 cm−1, while the cell dimensions forIII area=7.346(1),b=10.470(3),c=30.546(5) Å;Z=4,D x=1.212 g cm−3, μ(MoKα)=0.74 cm−1. The rings of the triterpene skeletons aretrans-cis-trans-cis connected. The conformations of both molecules are discussed. Also the preparation and the spectral data of (17R, 20S)-3,16-dioxo-25-nor-lanostan-24-oic acid (V) and (17R, 20S)-3,16,24-trioxo-25-hydroxy-16,24-seco-lanostan-25-acetate (VI) are given.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01796059
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    Mating behavior and mate recognition pheromone blocking of male receptors in Brachionus plicatilis Müller (Rotifera) (1995)
    Springer
    Hydrobiologia 313-314 (1995), S. 105-110 
    Details
    ISSN: 1573-5117
    Keywords: behavior ; mating ; pheromone ; receptors ; rotifers
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Copulatory behavior of three S and three L type B. plicatilis strains from different geographic areas was analyzed. A 29 KD surface glycoprotein on females, characterized as a Mate Recognition Pheromone (MRP), binds to receptors in the corona of males and blocks mate recognition. Blocking was observed in all S and L strains even though the MRP was isolated from a single L-type strain. Binding was quantified using image analysis and a 20-fold difference was observed among strains. A direct relationship between the male discrimination of females and the intensity of MRP binding to male receptors was found. This relationship might be useful as a tool to examine variation in the mate recognition systems of other rotifer species.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00025937
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 5
    Electronic Resource
    Electronic Resource
    Mating behavior in eight rotifer species: using cross-mating tests to study species boundaries (1997)
    Springer
    Hydrobiologia 356 (1997), S. 165-173 
    Details
    ISSN: 1573-5117
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract We characterized the mating behavior of eight freshwater rotifer species from five different families of Monogononts (Asplanchnidae, Brachionidae, Euchlanidae, Lecanidae, and Trichocercidae). Were corded the percentages of male-female encounters resulting in mating attempts and the number of completed copulations. The characterization of mating behavior also included data on: (1) duration of copulation, (2) female and male swimming speed, (3) sites of initial mating attempts, (4) sites of copulation, and (5) sizes of males and females. In the five families investigated, cross-mating tests may be used to assess the ability of males to discriminate conspecifics, establishing limits to gene flow. We also present data on two families, Brachionidae and Lecanidae where we used cross-mating tests to compare discrimination between conspecific females and those of other species. Brachionus calyciflorus males attempted mating with females of the closely related genus Plationus, but did not attempt mating with Keratella Americana females. Males of other three Brachionidae species only attempted mating with nonspecific females. Lecane quadridentata males attempted to mate with females of two different Lecane species besides their own. Percentages of mating attempts and completed copulations were quantified in all crosses. Lower percentages of copulation after a mating attempt were found among brachionids than among non-brachionids. These data demonstrate that male discrimination of females is an effective pre-mating reproductive barrier in several species of Monogonont rotifers. These results, further suggest that investigations of mating behavior are useful for determining species boundaries in rotifers and perhaps other zooplankters.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1003194216467
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 6
    Electronic Resource
    Electronic Resource
    Cross-mating tests re-discovered: a tool to assess species boundaries in rotifers (1998)
    Springer
    Hydrobiologia 287-388 (1998), S. 109-115 
    Details
    ISSN: 1573-5117
    Keywords: behavior ; mating ; evolution ; taxonomy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The recent isolation of a mate recognition pheromone in the marine rotifer Brachionus plicatilis Müller has shed new light on the mate recognition system of rotifers. One result is improved understanding of the importance of mating behavior as a highly efficient process used by rotifers to choose conspecifics. There are many differences in the main characteristics of mating behavior in members of five different families of rotifers. The present work describes the use of these characteristics to assess species boundaries, especially where boundaries between two or more species are unclear. The method proposed here can assess quantitatively the response of males of one species to females of a questionable taxon by measuring the percentage of matings initiated and the number of completed copulations. The data generated can then be used together with molecular, morphological, and other data to determine the species boundaries. This approach can help distinguish between morphological differences resulting from evolutionary divergence of species and morphological differences induced by environmental or ecological factors.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1017005602735
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 7
    Electronic Resource
    Electronic Resource
    Comparative binding of antibody to a mate recognition pheromone on female Brachionus plicatilis and Brachionus rotundiformis (Rotifera) (1997)
    Springer
    Hydrobiologia 358 (1997), S. 71-76 
    Details
    ISSN: 1573-5117
    Keywords: mate recognition ; pheromones ; antibody ; reproductive isolation ; rotifers
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The work of Kazutsugu Hirayama over the past 25 yearspromoted the wide use of the marine rotifer Brachionusplicatilis as an experimental model in zooplanktonecology. His reports about the nature of geneticvariation in the B. plicatilis complex stimulated usto investigate how mate recognition maintains speciesboundaries. For the past several years, we haveexamined chemical communication between female andmale B. plicatilis. Here we report on the comparativebinding of polyclonal antibody against the materecognition pheromone (MRP) to three B. plicatilisstrains and three B. rotundiformis strains.Quantification of anti-MRP binding permitsinvestigation of how the female mating signal differsamong closely related Brachionus species and strains.Antibody binding reflects differentiation independentof the male receptor which has been describedelsewhere. Anti-MRP bound to females of all sixstrains and was localized in the corona. Antibodybinding greatly reduced mating in all three B. plicatilis strains. However, antibody bindingsignificantly reduced mating in only one of the B. rotundiformis strains. The MRP of both species has asimilar molecular weight, but the differential bindingsuggests that the mate recognition pheromone onfemales has differentiated in B. plicatilis and B. rotundiformis.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1003121531835
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 8
    Electronic Resource
    Electronic Resource
    Cross-mating tests re-discovered: a tool to assess species boundaries in rotifers (1998)
    Springer
    Hydrobiologia 387-388 (1998), S. 109-115 
    Details
    ISSN: 1573-5117
    Keywords: behavior ; mating ; evolution ; taxonomy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The recent isolation of a mate recognition pheromone in the marine rotifer Brachionus plicatilis Müller has shed new light on the mate recognition system of rotifers. One result is improved understanding of the importance of mating behavior as a highly efficient process used by rotifers to choose conspecifics. There are many differences in the main characteristics of mating behavior in members of five different families of rotifers. The present work describes the use of these characteristics to assess species boundaries, especially where boundaries between two or more species are unclear. The method proposed here can assess quantitatively the response of males of one species to females of a questionable taxon by measuring the percentage of matings initiated and the number of completed copulations. The data generated can then be used together with molecular, morphological, and other data to determine the species boundaries. This approach can help distinguish between morphological differences resulting from evolutionary divergence of species and morphological differences induced by environmental or ecological factors.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1017005602735
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 9
    Electronic Resource
    Electronic Resource
    Effect of temperature and food concentration in two species of littoral rotifers (1998)
    Springer
    Hydrobiologia 287-388 (1998), S. 341-348 
    Details
    ISSN: 1573-5117
    Keywords: Lecanidae ; life-table ; mortality ; reproduction rate ; survivorship
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract We performed life-table experiments with two species of the littoral rotifers Lecane luna (O.F. Müller, 1776) and Lecane quadridentata (Ehrenberg, 1832). Three different temperatures (20, 25 and 30°C) and food concentrations of Nannochloris oculata (1×107, 5×106, and 1×106 cells ml-1) were investigated. We found important differences between both species in all the treatments regarding offspring sizes, hatching percentages, life span and reproductive rates. Our data on hatching percentages of asexual eggs suggested that the optimal temperature for both species is in the 20–25°C range. On the other hand, reproductive data placed the optimal temperature near 25°C. This information can be used to develop aquatic toxicology tests with littoral species.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1017099906853
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 10
    Electronic Resource
    Electronic Resource
    Relationship between thigmotropism and Candida biofilm formation in vitro (1998)
    Springer
    Mycopathologia 144 (1998), S. 125-129 
    Details
    ISSN: 1573-0832
    Keywords: biofilm ; Candida albicans ; Candida tropicalis ; saliva ; serum ; thigmotropism
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract The biofilm formation of the oral fungal pathogen Candida on denture acrylic strips coated with saliva or serum was examined in relation to the ability to induce hyphae by thigmotropic reaction, using C. albicans (4 isolates), C. glabrata (3 isolates) and C. tropicalis (3 isolates). Both the degree of biofilm formation and the amount of hyphae exhibiting thigmotropism varied depending upon both the species and strains of Candida. Although there was no significant correlation between the amount of hyphae induced by thigmotropic reaction of fungal isolates and biofilm formation on uncoated control specimens (r = 0.577; p 〈 0.05), the ability of hyphae induced by thigmotropic reaction significantly correlated with the amount of both saliva- and serum-admixed biofilms (r = 0.734; p 〈 0.05 and r = 0.793; p 〈 0.01, respectively). Taken together our in vitro data suggested that the hyphal induction by thigmotropic reaction is of importance in candidal biofilm formation on saliva- or serum-coated acrylic surfaces.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1007073930933
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...