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  • 1
    Electronic Resource
    Electronic Resource
    Does Coastal Foredune Stabilization with Ammophila arenaria Restore Plant and Arthropod Communities in Southeastern Australia? (2000)
    Boston, MA, USA : Blackwell Science Inc
    Restoration ecology 8 (2000), S. 0 
    Details
    ISSN: 1526-100X
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: In this study we examine whether stabilization of denuded coastal foredunes in southeastern Australia with the exotic grass species Ammophila arenaria (marram grass) restores plant and ground-active arthropod assemblages characteristic of undisturbed foredunes. Vascular plants and arthropods were sampled from foredunes that had been stabilized with marram grass in 1982, and from foredunes with no obvious anthropogenic disturbance (control dunes). All arthropods collected were sorted to Order, and ants (81.5% of all specimens) were further sorted to morphospecies. Abundance within arthropod Orders, as well as richness, composition, and structure of the plant and ant assemblages from control and stabilized dunes, were compared. The abundance of Diptera was significantly greater on stabilized dunes, while the abundance of Isopoda was significantly greater on control dunes. There were no significant differences in morphospecies richness or composition of ant assemblages on the two dunes types, although some differences in the abundances of individual morphospecies were observed. By contrast, stabilized dunes exhibited lower plant species richness and highly significant differences in plant species composition, due mainly to the large projected foliage cover of marram grass. The study revealed that after 12 years, the vegetation composition and structure of stabilized dunes was still dominated by marram grass and, as a result, invertebrate assemblages had not been restored to those characteristic of undisturbed foredunes.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1046/j.1526-100x.2000.80040.x
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  • 2
    Electronic Resource
    Electronic Resource
    Investigation of the Regulation of Pigmentation in α-Melanocyte-Stimulating Hormone Responsive and Unresponsive Cultured B16 Melanoma Cells (1989)
    Oxford, UK : Blackwell Publishing Ltd
    Periodontology 2000 2 (1989), S. 0 
    Details
    ISSN: 1600-0757
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: In vitro melanocyte-stimulating hormone (MSH) stimulates melanogenesis in some, but not all, melanocytes and melanoma cells. In an attempt to explain this variation in response to αMSH, we examined cyclic adenosine monophosphate (cAMP) accumulation, tyrosinase activity, and melanin production in primary (1°) murine B16 melanoma cells and in two B16 cell lines (B16 F1 and B16 F10) that are known to respond to αMSH. In vivo all three B16 melanoma cell types produced pigmented tumours. In vitro αMSH increased tyrosinase activity and melanin content in the F1 and F10 cells but not in the B16 1° cells. αMSH, however, increased cAMP production in all three cell types, confirming that the inability of B16 1° cells to produce melanin in response to αMSH is not due to a lack of αMSH receptors or cAMP response to αMSH. Further, we present evidence for a separate pathway of melanogenesis that is independent of cAMP as calmodulin antagonists, which do not elevate cAMP, increased tyrosinase activity, and melanin production in both 1° and F1 cells.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1600-0749.1989.tb00181.x
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  • 3
    Electronic Resource
    Electronic Resource
    Patterns of invertebrate biodiversity across a natural edge (2003)
    Oxford, UK : Blackwell Science Pty
    Austral ecology 28 (2003), S. 0 
    Details
    ISSN: 1442-9993
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: Abstract Most ecologists are comfortable with the notion of habitats as recognizable entities and also with situations where the junction between two adjacent habitats forms a discrete edge. Such edges form naturally because of sharp changes in important edaphic, geomorphological, climatic or chemical properties to which plants, in particular, respond. Less clear is the effect of such edges on assemblages of mobile organisms, especially invertebrates that operate at relatively small spatial scales. The objective of the present study was to sample invertebrate composition across a natural edge between a well-developed riparian habitat on fluvial sands and a saltbush habitat developed on a stony gibber plain in a semi-arid region of New South Wales, Australia. A total of 150 pitfall traps on five 1-km-long transects that straddled the edge produced more than 13 000 adult specimens from 21 ordinal invertebrate taxa. A total of 10 446 beetle, ant, wasp, fly and springtail specimens were further sorted into 426 morphospecies. Comparisons and estimates of trends in abundance and richness were made, along with computation of multivariate dissimilarity and permutation statistics, to determine if the land system edge was coincident with changes in invertebrate abundance and composition. These analyses were unable to detect disjunctions in diversity coincident with the edge. The data suggest that many taxa are either present consistently in both habitats or are mostly found in one habitat but ‘leak’ several hundred metres across into the other. Few taxa were unique to either habitat. The result is that assemblage composition for invertebrates changes gradually over distances of up to 400 m either side of the edge and that the distance to a recognizable change in composition is taxon dependent. Even sharp habitat edges, as defined by discrete changes in soils and plants, are not edges but broad transition zones for many invertebrate taxa. There are several implications of these results, especially for landscape ecology.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1046/j.1442-9993.2003.01240.x
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  • 4
    Electronic Resource
    Electronic Resource
    Spatial scaling of microbial eukaryote diversity (2004)
    [s.l.] : Macmillian Magazines Ltd.
    Nature 432 (2004), S. 747-750 
    Details
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] Patterns in the spatial distribution of organisms provide important information about mechanisms that regulate the diversity of life and the complexity of ecosystems. Although microorganisms may comprise much of the Earth's biodiversity and have critical roles in biogeochemistry and ...
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1038/nature03034
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  • 5
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    Unknown
    Love's Island (1917)
    New York, N.Y. : Periodicals Archive Online (PAO)
    Harper's. 136 (1917:Dec.-1918:May) 130 
    Details
    ISSN: 0017-789X
    Topics: General, Interdisciplinary
    Notes: VERSE
    URL: http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&res_dat=xri:pao:&rft_dat=xri:pao:article:5128-1917-136-00-000109
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  • 6
    Electronic Resource
    Electronic Resource
    The role of calmodulin in the gravitropic response of the Arabidopsis thaliana agr-3 mutant (1996)
    Springer
    Planta 199 (1996), S. 343-351 
    Details
    ISSN: 1432-2048
    Keywords: Arabidopsis ; Calmodulin ; Gravitropism
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Calmodulin, a primary plant calcium receptor, is known to be intimately involved with gravitropic sensing and transduction. Using the calmodulin-binding inhibitors trifluoperazine, W7 and calmidazolium, gravitropic curvature of Arabidopsis thaliana (L.) Heynh, ecotype Landsberg, roots was separable into two phases. Phase I was detected at very low concentrations (0.01 μM) of trifluoperazine and calmidazolium, did not involve growth changes, accounted for about half the total curvature of the root and may represent the specific contribution of the cap to gravity sensing. Phase II commenced around 1.0 μM and involved inhibition of both growth and curvature. The agr-3 mutant exhibited a reduced gravitropic response and was found to lack phase I curvature, suggesting that the mutation alters either use or expression of calmodulin. The sequences of wild-type and agr-3 calmodulin (CaM-1) cDNAs, which are root specific were completely determined and found to be identical. Upon gravitropic stimulation, wild-type Arabidopsis seedlings increased calmodulin mRNA levels by threefold in 0.5 h. On the other hand, gravitropic stimulation of agr-3 decreased calmodulin mRNA accumulation. The possible basis of the two phases of curvature is discussed and it is concluded that agr-3 has a lesion located in a general gravity transmission sequence, present in many root cells, which involves calmodulin mRNA accumulation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00195725
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  • 7
    Electronic Resource
    Electronic Resource
    A DNA fragment containing the groE genes can suppress mutations in the Escherichia coli dnaA gene (1986)
    Springer
    Molecular genetics and genomics 202 (1986), S. 446-454 
    Details
    ISSN: 1617-4623
    Keywords: groE ; dnaA ; Replication initiation ; E. coli
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary An 8.2 kb fragment of E. coli chromosomal DNA, when cloned in increased copy number, suppresses the dnaA46 mutation, and an abundant protein of about 68 kd (60 kd when measured by us), encoded by the fragment, is essential for the suppression (Takeda and Hirota 1982). Mapping experiments show that the fragment originates from the 94 min region of the chromosome. It encodes several proteins but only one abundant polypeptide of the correct size, the product of the groEL gene. Suppression by the fragment is allele specific; those mutations which map to the centre of the gene are suppressed. Other initiation mutants including dnaA203, dnaA204, dnaA508, dnaAam, dnaC, dnaP and dnaB252 are not suppressed. Most suppressed strains are cold-sensitive suggesting an interaction between the mutant proteins (or their genes) and the suppressing protein or proteins.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00333275
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  • 8
    Electronic Resource
    Electronic Resource
    Packaging of transducing DNA by bacteriophage P1 (1988)
    Springer
    Molecular genetics and genomics 214 (1988), S. 523-532 
    Details
    ISSN: 1617-4623
    Keywords: Transduction ; Bacteriophage P1 ; Packaging ; Quantitative Southern hybridization
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary P1 transduces bacterial chromosomal markers with widely differing frequencies. We use quantitative Southern hybridisations here to show that, despite this, most markers are packaged at similar levels. Exceptions are a group of markers near 2 min and another at 90 min which seem to be packaged at levels two-to threefold higher. We thus conclude that certain marker frequency variations in transduction can be explained by differences in packaging level, but that most cannot. The limited range in packaging levels suggests that P1 can initiate the packaging of chromosomal DNA from many sites. This idea is supported by our failure to find any chromosomal sequences with homology to the phage pac site and by the occurrence of hybridising bands which seem to suggest sequential packaging from a large number of specific sites. We eliminate the possibility that chromosomal DNA packaging is the result of endonucleolytic cutting by the P1 res enzyme.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00330490
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