The corticostatic (anti-ACTH) and cytotoxic activity of peptides isolated from fetal, adult and tumor-bearing lung

The possibility that corticosteroids influence lung maturation was suggested in 1968 by Buckingham et al. and supported by studies mounted in humans and in rabbits by Liggins and Howie and by a collaborative study from the N.I.H. To our knowledge no reverse process, i.e. the regulation of adrenal function by the lung, has been postulated. In attempting to isolate ACTH from fetal lung we found peptides which depressed corticosterone production. Eventually, we isolated a group of peptides from rabbit fetal lung which showed potent inhibition of corticosterone production in rat adrenal cell suspensions. Using high-resolution reverse-phase HPLC and high-sensitivity gas-phase sequencing techniques the primary structure of one of these peptides has been determined and it was called corticostatin. The adult rabbit lung contains a large quantity of a very similar peptide, which elutes close to corticostatin but whose amino acid composition differs by a single glycine and possibly a serine. This peptide is also potently corticostatic. We have isolated homologous human peptides but these show no apparent corticostatic activity in rat adrenal cell suspensions. They do, however, show interesting effects on in vitro growth of lung cell lines.     

Robust estimation of parasite component community richness.

The performance of 2 nonparametric estimators of species richness, the bootstrap (S(B)) and kth-order jackknife (S(Jk)), are compared using simulated parasite communities. The parameters of the simulation match those of an earlier comparison that favored S(B) as an estimator but did not include S(Jk). S(Jk) is the least biased of the 2 estimators. Whereas the bias of S(B) is significantly affected by true species richness and the proportion of rare species, the bias of S(Jk) is relatively insensitive to changes in these parameters, and is, therefore, recommended as a robust estimator of species richness.     

A fine structural survey of the development of the adult fat body of Leptinotarsa decemlineata

The fat body of a female Colorado potato beetle, Leptinotarsa decemlineata, at adult ecdysis, contains a large number of protein granules which are composed of light and dark zones. Part of the light zone in some of these granules is believed to be urate. During the first two days after adult ecdysis, fat body development is not essentially different in females reared either under long- or short-day conditions. Protein granules and large vacuoles disappear and the first cell organelles are regenerated. The effect of the photoperiod on the histological structure of the fat is expressed after these events. In females reared under long-day conditions, the fat body becomes specialized for vitellogenin synthesis. Under short-day conditions, the fat body stores massive amounts of lipid until day 6 after adult ecdysis. Then the first electron-dense protein granules develop near the nucleus, and on day 10 the first autophagic vacuoles are seen. These structure changes are discussed in connection with the known biochemical properties of the adult faty body of Leptinotarsa.