Library

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
    Causal connection between detoxification enzyme activity and consumption of a toxic plant compound (1996)
    Springer
    Journal of comparative physiology 179 (1996), S. 255-261 
    Details
    ISSN: 1432-1351
    Keywords: Insect feeding ; P450 enzyme induction ; Nicotine ; Detoxification enzymes ; Allelochemicals
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract Insect herbivores can increase their detoxification activities against a particular plant poison in response to prolonged ingestion of the same compound. For example, larval tobacco hornworms (Manduca sexta) experience a dramatic increase in cytochrome P450 activity against nicotine after ingesting nicotine. While it is generally assumed that this induction process permits increased consumption of toxic plant tissues, we are not aware of any direct experimental support for this assumption. Using a two-tiered approach, we examined the functional significance of P450 induction to M. sexta larvae ingesting a toxic but non-deterrent concentration of nicotine. First, we related the time-course of P450 induction in midgut microsomes to changes in nicotine consumption. When offered a nicotine diet, larvae failed to show a significant increase in consumption before 36 h, which was coincident with the time-course of the induction of midgut P450 activities against aldrin and nicotine. Second, we determined whether inhibiting the induced P450 activities affected nicotine consumption. We found that the increase in nicotine consumption following the induction of nicotine metabolism could be strongly inhibited by treatment with piperonyl butoxide, which by itself did not inhibit consumption. These results provide direct evidence for a causal connection between P450-mediated detoxification activity and consumption of a toxic plant compound.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00222792
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    Multivariate discrimination of host use by dwarf mistletoeArceuthobium vaginatum subsp.cryptopodum: Inter- and intraspecific comparisons (1996)
    Springer
    Journal of chemical ecology 22 (1996), S. 295-305 
    Details
    ISSN: 1573-1561
    Keywords: Dwarf mistletoe ; Arceuthobium vaginatum ; ponderosa pine ; Pinus ponderosa ; lodgepole pine ; Pinus contorta ; parasitic plants ; monoterpenes ; differential selection ; host resistance ; host chemistry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract The parasitic dwarf mistletoeArceuthobium vaginatum attacksPinus ponderosa as its primary host andP. contorta as an occasional host. Within ponderosa pine stands there is also differential parasitism among individual trees. We compared biochemical features of phloem and xylem oleoresin between infected individuals of the two pine species (N=15 for each species) and also between infected (N=30) and nearby uninfected (N=30) ponderosa pine conspecifics. There were significant differences in chemical features, both at the interspecific (P. ponderosa vs.P. contorta) and intraspecific (P. ponderosa) levels. Discriminant function analysis based on chemical features of phloem correctly classified all trees used in the analysis as eitherP. ponderosa orP. contorta, and 95% of all ponderosa pine trees as either parasitized or nonparasitized. Monoterpene composition of oleoresin was distinct between species, and differences between parasitized and nonparasitizedP. ponderosa were also significant. Many of the observed chemical differences are probably constitutive, although levels of nonstructural carbohydrates and α-pinene may change in response to dwarf mistletoe infection. Biochemical differences at the intraspecific level were distinct from interspecific differences. Patterns of differential attack can have genetic consequences upon both the parasite and its hosts, and, in the process, may contribute to the evolution of host races of the parasite and to the evolution of host resistance within ponderosa pine.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02055100
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    Time-course study and partial characterization of a protein on hyphae of arbuscular mycorrhizal fungi during active colonization of roots (1996)
    Springer
    Plant and soil 181 (1996), S. 193-203 
    Details
    ISSN: 1573-5036
    Keywords: fungal protein ; heat-stable protein ; Glomales ; vesicular arbuscular mycorrhizal fungi
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Material on the surface of hyphal walls of arbuscular mycorrhizal fungi (AMF) during active colonization of plant roots was detected by a monoclonal antibody. Pot-cultured isolates of Glomus, Acaulospora, Gigaspora, Scutellospora, and Entrophospora had immunofluorescent material (IM) on younger, thinner, intact hyphae, but IM was scant to absent on thicker, melanized or lysing hyphae. Colonization of corn (Zea mays L.), Sudangrass (Sorghum sudanense (Piper) Staph.) or red clover (Trifolium pratense L.) was examined during 5 months of plant growth by removing cores and performing an indirect immunoassay on roots with attached hyphae. Fresh spores of some Glomus spp. had IM on the outer layer of the spore wall. Abundant IM was seen on root hairs of plants colonized by some isolates, and some IM was detected on root surfaces of all plants examined even during early colonization. After cultures were dried, hyphae, roots and spores had little to no IM. Uninoculated control roots had very rare, small patches of IM. An immunoreactive protein was extracted from hyphae of Gigaspora and Glomus isolates by using 20mM citrate (pH 7.0) at 121°C for 90 min. Gel electrophoresis profiles indicated that all isolates tested had the same banding patterns. Lectin-binding of extracted protein is suggestive of a glycoprotein. The immunofluorescence assay can be used to examine root sections for active colonization by AMF, and the potential use of the protein to quantify AMF activity in soil is discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00012053
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    Evidence for a diazepam-binding inhibitor (DBI) benzodiazepine receptor-like mechanism in ecdysteroidogenesis by the insect prothoracic gland (1998)
    Springer
    Cell & tissue research 294 (1998), S. 161-168 
    Details
    ISSN: 1432-0878
    Keywords: Key words Diazepam-binding inhibitor (DBI) ; Benzodiazepine receptor (BZD) ; Prothoracic gland (PG) ; Manduca sexta (Insecta)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract  The diazepam-binding inhibitor (DBI) is a 10-kDa highly evolutionarily conserved multifunctional protein. In mammals, one of DBI’s functions is in the activation of steroid hormone biosynthesis via binding to a specific outer mitochondrial membrane receptor (benzodiazepine receptor, BZD) and promoting cholesterol transport to the inner membrane. In this work, a multitiered approach was utilized to study the role of this receptor-like activity in ecdysteroidogenesis by larval insect prothoracic glands (PGs). First, both DBI protein and messenger RNA (mRNA) levels were correlated with peak PG ecdysteroid production. In vitro ecdysteroid production was stimulated by the diazepam analogue FGIN 1-27 and inhibited anti-DBI antibodies. The DBI protein was found distributed throughout PG cells, including regions of dense mitochondria, supposed subcellular sites of ecdysteroid synthesis. Finally, a potential mitochondrial BZD receptor in PG cells was demonstrated by photoaffinity labeling. These results suggest an important role for the insect DBI in the stimulation of steroidogenesis by prothoracic glands and indicate that a pathway for cholesterol mobilization leading to the production of steroid hormones appears to be conserved between arthropods and mammals.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004410051166
    Library Location Call Number Volume/Issue/Year 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...