Pre-and post-natal ontogeny of neutral endopeptidase 24-11 (‘enkephalinase’) studied by in vitro autoradiography in the rat

Neutral endopeptidase (NEP, enkephalinase, CALLA) which is present in various neural and non-neural tissues, is able to cleave a variety of regulatory peptides. The distribution of NEP has been studied during rat pre-and post-natal development by autoradiography after in vitro binding of the tritiated inhibitor [³H]HACBO-Gly to whole-body and organ sections. In the central nervous system (CNS), where the presence of NEP has been related to the termination of the action of enkephalins, the external layer of the olfactory bulbs is the only structure prominently labeled before birth. Other CNS structures rich in NEP in the adult, such as the nigrostriatal tract, are progressively labeled after birth. Outside the CNS, the progressive appearance of NEP in the kidney, the lungs and the salivary glands suggests its concomitant involvement in adult physiological functions, including fluid balance control, possibly by cleaving the atrial natriuretic peptide (ANP) and other peptides. On the other hand, transient or enhanced expression of NEP is observed during the development of several organs such as the sensory organs, the heart and the major blood vessels, the intestine, the bones and the genital tubercle. In addition to the still incompletely known physiological functions of the enzyme, the developmental pattern of its expression in several tissues strongly suggests a modulatory role for NEP in the ontogeny of a large number of organs.     

Biological properties of a CD4 immunoadhesin

Molecular fusions of CD4, the receptor for human immunodeficiency virus (HIV), with immunoglobulin (termed CD4 immunoadhesins) possess both the gp120-binding and HIV-blocking properties of recombinant soluble CD4, and certain properties of IgG, notably long plasma half-life and Fc receptor binding. Here we show that a CD4 immunoadhesin can mediate antibody-dependent cell-mediated cytotoxicity (ADCC) towards HIV-infected cells, although, unlike natural anti-gp120 antibodies, it does not allow ADCC towards uninfected CD4-expressing cells that have bound soluble gp120 to the CD4 on their surface. In addition, CD4 immunoadhesin, like natural IgG molecules, is efficiently transferred across the placenta of a primate. These observations have implications for the therapeutic application of CD4 immunoadhesins, particularly in the area of perinatal transmission of HIV infection.     

Natural pollution of continental waters by the antioxygenic effect of phytomelanin genesis in aqueous extract of autumn leaves, especially poplars]

Phenolase-acid phenol systems are present in variable amounts, variable proportion and variable water solubility in the autumn leaves of trees and bushes. The oxidative polycondensations into phytomelanins caused by these systems confer antioxygen properties to aqueous macerations of senescent leaves, which are sometimes very intense. They induce therefore a biochemical natural pollution of continental waters. The Poplars proved to be particularly deleterious.     

Acetylsalicylic acid-induced morphological changes in the ductus arteriosus of the chick embryo

Summary The effect of acetylsalicyclic acid upon the ducti arteriosi of the embryonic chick was studied. A spectrum of gross malformations and histological findings associated with premature closure of the right ductus arteriosus is presented.This study was supported by grant No. HL18050, National Heart, Lung and Blood Institute, National Institutes of Health, Bethesda, Maryland. The authors wish to extend their appreciation to John M. Opitz, University of Wisconsin Department of Genetics, for his generous support. This report was presented in part at the Fiftieth Scientific Sessions, American Heart Association Meetings, Miami, Florida, November 1977.     

Two new aminopeptidases from Ochrobactrum anthropi active on D-alanyl-p-nitroanilide

Two new enzymes which hydrolyse D-alanyl-p-nitroanilide have been detected in Ochrobactrum anthropi LMG7991 extracts. The first enzyme, DmpB, was purified to homogeneity and found to be homologous to the Dap protein produced by O. anthropi SCRC C1-38 (ATCC49237). The second enzyme, DmpA, exhibits a similar substrate profile when tested on p-nitroanilide derivatives of glycine and L/D-alanine, but the amounts produced by the Ochrobactrum strain were not sufficient to allow complete purification. Interestingly, the DmpA preparation also exhibited an L-aminopeptidase activity on the tripeptide L-Ala-Gly-Gly but it was not possible to be certain that the same protein was responsible for both p-nitroanilide and peptide hydrolysing activities. The gene encoding the DmpA protein was cloned and sequenced. The deduced protein sequence exhibits varying degrees of similarity with those corresponding to several open reading frames found in the genomes of other prokaryotic organisms, including Mycobacteria. None of these gene products has been isolated or characterised, but a tentative relationship can be proposed with the NylC amidase from Flavobacterium sp. K172. Received 7 December 1998; received after revision 15 March 1999; accepted 22 March 1999