Response to cecropia cocoons of Mus musculus and two species of Peromyscus
SummaryIn rural areas cocoons of overwintering Hyalophora cecropia spum close to the ground are opened and the pupae eaten by small mammals, but in urban areas, where cecropia populations are much larger, the cocoons are almost never opened by mammals. Peromyscus leucopus noveboracensis and P. maniculatus bairdii are abundant in rural areas, but are largely replaced by Mus musculus in urban areas. In laboratory experiments P. l. noveboracensis invariably opened cecropia cocoons and ate the pupae. P. m. bairdii were slower to open cecropia cocoons and two of twelve did not open one at all. M. musculus, on the other hand, never opened cecropia cocoons although they gnawed the silk and ate uncovered pupae. Cocoons opened in the laboratory by the two species of Peromyscus cannot be distinguished from each other or from cocoons opened in the field.
Antimicrobial components in the cocoon silk of silkworm, Bombyx mori.
Silkworm spins silk fibers to make the cocoon to protect the pupa from predators and pathogenic microbes. To understand the defense mechanism of the cocoon, many antimicrobial proteins are currently identified. The functionality of these proteins is studied, including protease inhibitors and seroins. Protease inhibitors are incredibly variable in sequences and domains, and most of them contain multiple pairs of disulfide bonds. Thereby they have stable structures and activities. Seroins have two motifs: the proline-rich N-terminal motif and the sequence conserved C-terminal motif. Protease inhibitors mainly play antifungal roles, whereas seroins have broad-spectrum antimicrobial activities against bacteria, fungi and viruses. These antimicrobial proteins show higher abundance in the sericin layers than in the fibroin layer and are more abundant in the outer cocoon layer than in the inner cocoon layer. Besides silk proteins, the silkworm cocoon also contains small amounts of non-protein antimicrobial components such as organic acids, alkaloids, flavonoids, and heterocyclic compounds. This review describes the extraction methods, expression pattern, microbiostatic mechanism, application fields and advantages of the antimicrobial components in the silkworm cocoon. The in-depth understanding of antimicrobial silk components will help us improve the processing technology of cocoons and expand the application fields of the cocoons.
Lupin alkaloids from teratogenic and nonteratogenic lupins. II. Identification of the major alkaloids by tandem gas chromatography-mass spectrometry in plants producing crooked calf disease.
The major alkaloids of lupin plants producing crooked calf disease were identified by tandem gas chromatography-mass spectrometry and infrared analysis. The gas chromatography peak invariably present in teratogenic plants proved to be anagyrine. A minor but irregular contaminant of the peak was α-isolupanine. Other alkaloids present but apparently not associated with crooked calf disease were lupanine and two others that were probably epimethoxylupanine and 5,6-dehydrolupanine.