Pyrrhocoris apterus is a black and red European bug the size of a finger-nail. It is normally found underneath lime trees (Tilia spp.) walking about on the leaf litter and feeding on the fallen seeds. It is readily reared in the laboratory in jars, on a diet of water and dry lime seeds, and with crumpled paper as a substitute for the leaf litter. We have recently found, however, that the nature and source of the paper is important. Reared on the advertisement pages of Nature, growth and reproduction were normal, but on certain other papers all the emergent adults were deformed, superficially resembling the metathetelic (juvenile) extra instars obtained by the implantation of the corpus allatum into last-stage larvae. So far the following samples of paper have been found to produce this effect: pages from Scientific American, paper tissues made by Dixcel and paper tissues and some batches of
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D. B. CARLISLE, P. E. ELLIS, Z. BRETTSCHNEIDEROVÁ, and V. J. A. NOVÁK
H von Horn, C Ekstrom, E Ellis, H Olivecrona, C Einarsson, M Tally, and TJ Ekstrom
The regulation of the insulin-like growth factor-II gene (IGF2) is complex and involves the usage of four promoters resulting in different 5' untranslated regions, but with a common translated product. The IGF2 gene product is a mitogenic and survival factor that has been suggested to be important for a normal fetal development and cancer. In this paper we present evidence suggesting that the human IGF2 gene is regulated by GH, and that this regulation occurs in a promoter-specific way. Three lines of evidence support this finding. First, in vivo data from patients treated with GH (one injection or daily injections for 5 consecutive days) showed an increase in the IGF2 P2 promoter derived transcript after acute treatment, and of the P4 promoter transcript after short-term treatment while the P1 promoter derived transcript did not show any significant change. Secondly, isolated human liver cells treated with GH for 2 h displayed an upregulation of the P2 promoter derived transcript. Thirdly, employing transfection experiments in GH-receptor positive CHO cells with P2 and P4 promoter-luciferase constructs, an upregulation by GH was evident, while a P1 promoter construct was unresponsive. We suggest that GH may be a physiological regulator of IGF2 in humans.
S. T. Ellis, R. B. Heap, A. R. Butchart, V. Rider, N. E. Richardson, M.-W. Wang, and M. J. Taussig
Anti-progesterone monoclonal antibody prevents the establishment of pregnancy in BALB/c mice by the prevention of implantation when injected i.p. 32 h after mating. To determine the specificity of this effect, mice were injected with immune and non-immune purified mouse immunoglobulins. The results show that anti-implantation efficacy was due to high-affinity antibody which bound progesterone since two further mouse immunoglobulin (Ig) G1 preparations, mouse IgA and mouse IgM which failed to bind the steroid, had no effect on pregnancy rates. From a panel of anti-progesterone monoclonal antibodies, six with a high affinity (affinity constant, 0·24–0·80 litres/nmol) and specificity for progesterone were selected for additional studies. Anti-implantation efficacy for five antibodies was similar, with a 50% effective dose within the range of 0·8–2·0 nmol. Antibody reached high concentrations in plasma within 12 h after i.p. injection, and declined with a half-life of about 80 h. Purified F(ab′)2 fragments of antibody also bound progesterone, but were less effective than the native molecule in blocking pregnancy. The results show that implantation in the mouse can be blocked by a high-affinity antibody that binds progesterone and which is removed from the blood at a slow rate.
J. Endocr. (1988) 118, 69–80