PubMed Health⌕ Search

Biomedical subjects

F C Schroeder

Publications and source records attributed to F C Schroeder.

8 recordsLinked to original sources
PubMed2001

Host recognition by the tobacco hornworm is mediated by a host plant compound.

It is generally believed that animals make decisions about the selection of mates, kin or food on the basis of pre-constructed recognition templates. These templates can be innate or acquired through experience. An example of an acquired template is the feeding preference exhibited by larvae of the moth, Manduca sexta. Naive hatchlings will feed and grow successfully on many different plants or artificial diets, but once they have fed on a natural host they become specialist feeders. Here we show that the induced feeding preference of M. sexta involves the formation of a template to a steroidal glycoside, indioside D, that is present in solanaceous foliage. This compound is both necessary and sufficient to maintain the induced feeding preference. The induction of host plant specificity is at least partly due to a tuning of taste receptors to indioside D. The taste receptors of larvae fed on host plants show an enhanced response to indioside D as compared with other plant compounds tested.

Animals↗
PubMed2001

Production of a cyanogenic secretion by a thyridid caterpillar (Calindoea trifascialis, Thyrididae, Lepidoptera).

The thyridid caterpillar, Calindoea trifascialis, when disturbed, emits a defensive secretion from two sac-like glands that open dorsolaterally on the first abdominal segment. The larva has two arm-like protuberances that project outward from the body just in front of the gland openings. These "arms", which are wetted by secretion when the larva activates its glands, appear to function specifically for administration of the fluid. A primary component of the secretion in mandelonitrile, a cyanogenic compound, but the fluid also contains other potential deterrents, including benzaldehyde, benzoic acid, (E,E)-alpha-farnesene, and 3-methylbutyl-3-methylbutanoate. Tests done in the field in Vietnam, where the species is native, showed the secretion to be protective against ants.

Acetonitriles↗
PubMed2000

Chemical defense: bestowal of a nuptial alkaloidal garment by a male moth on its mate.

Males of the moth Cosmosoma myrodora (Arctiidae) acquire pyrrolizidine alkaloid by feeding on the excrescent fluids of certain plants (for instance, Eupatorium capillifolium). They incorporate the alkaloid systemically and as a result are protected against spiders. The males have a pair of abdominal pouches, densely packed with fine cuticular filaments, which in alkaloid-fed males are alkaloid laden. The males discharge the filaments on the female in bursts during courtship, embellishing her with alkaloid as a result. The topical investiture protects the female against spiders. Alkaloid-free filaments, from alkaloid-deprived males, convey no such protection. The males also transmit alkaloid to the female by seminal infusion. The systemic alkaloid thus received, which itself may contribute to the female's defense against spiders, is bestowed in part by the female on the eggs. Although paternal contribution to egg defense had previously been demonstrated for several arctiid moths, protective nuptial festooning of a female by its mate, such as is practiced by C. myrodora, appears to be without parallel among insects.

Animals↗
PubMed2000

Chiral silylation reagents for the determination of absolute configuration by NMR spectroscopy.

We have investigated the use of chiral silylating reagents as analytical probes for determining the absolute stereochemistry of natural products by NMR spectroscopy. These reagents are prepared in high chemical yield in one step and can be used to derivatize chiral allylic alcohols which are incompatible with ester-based methodologies. Microscale ( approximately 400 nmol) derivatization conditions have been defined. The resulting siloxane diastereomers are readily distinguished by their (1)H NMR spectra.

Animals↗
PubMed1999

Miriamin, a defensive diterpene from the eggs of a land slug (Arion sp.).

The eggs of the land slug Arion sp. contain a diterpene, miriamin, characterized as a polyoxygenated geranylgeraniol derivative. In bioassays with a coccinellid beetle, Harmonia axyridis, miriamin was shown to be potently antifeedant, indicating that the compound plays a protective role in nature. It is suggested that mucilaginous soil-inhabiting organisms, given their intense exposure to pathogens and predators, may be a rich source of chemical defensive agents.

Animals↗
PubMed1998

Polyazamacrolides from ladybird beetles: ring-size selective oligomerization.

The pupal defensive secretion of the 24-pointed ladybird beetle, Subcoccinella vigintiquatuorpunctata, consists of a mixture of macrocyclic polyamines, dominated by the three dimeric, 30-membered macrocycles 11-13, derived from the two building blocks 11-(2-hydoxyethylamino)-5-tetradecenoic acid (9) and 11-(2-hydoxyethylamino)-5,8-tetradecadienoic acid (10). Smaller amounts of the four possible cyclic trimers of 9 and 10 were also detected, corresponding to 45-membered macrocycles. Structural assignments were based on NMR-spectroscopic investigations and HPLC-MS analyses. In addition, the all-S absolute configuration of the S. vigintiquatuorpunctata macrocycles was determined by comparison of derivatives of the natural material with enantiomerically pure synthetic samples. Comparing this alkaloid mixture with that of the pupal defensive secretion in related ladybird beetle species indicates that the degree of oligomerization of the 2-hydroxyethylamino carboxylic acid building blocks can be carefully controlled by the insects.

Alkaloids↗
PubMed1997

[Not Available].

Explore the source record for details and available documents.

Germany↗