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R Acher

Publications and source records attributed to R Acher.

At least 73 records · Page 4Linked to original sources
PubMed1986

Functional Kunitz inhibitor binding domain in plasmin-derived light chain as shown by affinity chromatography.

The light chain of plasmin, prepared by selective reduction of the interchain disulfide bridges, can be separated from the heavy chain by affinity adsorption onto Kunitz inhibitor/Sepharose. This adsorption involves the active center of plasmin because it does not occur if the light chain is derived from a plasmin previously blocked by the active site titrant p-nitrophenyl-p'-guanidinobenzoate. It can be deduced that the conformation of the inhibitor binding domain of plasmin is preserved in the free light chain.

Amino Acid Sequence↗
PubMed1986

[Phylogeny of neurohypophyseal hormones in birds: microidentification of mesotocin and vasotocin in the ostrich (Struthio camelus)].

Ostrich (Struthio camelus) neurohypophysial hormones have been isolated from 5 freeze-dried posterior pituitary glands. Purification has involved three steps: a first molecular sieving on Sephadex G-75 for eliminating proteins, a second molecular sieving on Bio-Gel P4 for separating the two active principles and a high pressure reverse-phase liquid chromatography (HPLC) on Nova-Pak C 18 with an 10 mM acetate-acetonitrile gradient for isolating each hormone. The active peptides have been identified by their retention time in HPLC and their amino acid composition. Mesotocin and vasotocin have thus been characterized. Although the phylogeny of Ratites is disputed, in particular their possible common origin with Carinates, which include most of the living birds, species of the first sub-class seem to have the same neurohypophysial hormones as those of the second.

Animals↗
PubMed1986

Ontogeny of bovine neurohypophysial hormone precursors. II. Foetal copeptin, the third domain of the vasopressin precursor.

Vasopressin, MSEL-neurophysin and a glycopeptide, here referred to as copeptin, are three fragments of a common protein precursor processed during axonal transport from hypothalamus to neurohypophysis. Neurohormones and neurophysins purified from 7-9-month-old bovine foetuses have previously been shown to be identical with those found in the adult. Copeptin has now been isolated from 7-9-month and 3-month-old bovine foetuses and chemically characterized. It can be concluded from the nature of the three precursors that the same vasopressin gene is expressed in the adult and the 7-9-month-old foetus.

Amino Acid Sequence↗
PubMed1985

The neurohypophysial hormones of the egg-laying mammals: identification of arginine vasopressin in the platypus (Ornithorhynchus anatinus).

Two neurohypophysial peptides have been purified from acetone desiccated posterior pituitary glands of the platypus (Ornithorhynchus anatinus) by molecular sieving and high-pressure liquid chromatography. A single pressor peptide, having an amino acid composition and a chromatographic retention time identical to those of arginine vasopressin, has been identified. A single oxytocic peptide has been isolated that ressembles oxytocin by its chromatographic retention time, but lack of material has prevented to obtain a correct amino acid composition. The pressor peptide is roughly four times more abundant than the oxytocic peptide. Neurohypophysial hormones of platypus seem similar to those of echidna, the other living prototherian, and to those of most placental mammals.

Amino Acids↗
PubMed1985

Neurohypophyseal hormones as evolutionary tracers: identification of oxytocin, lysine vasopressin, and arginine vasopressin in two South American opossums (Didelphis marsupialis and Philander opossum).

The neurohypophyseal hormones of two South American opossums (Didelphis marsupialis and Philander opossum) were isolated by molecular sieving and preparative high-pressure liquid chromatography (HPLC). One oxytocin-like and two vasopressin-like peptides were found in each species. These peptides have been identified by their amino acid composition and by their retention time in HPLC. Oxytocin, lysine vasopressin, and arginine vasopressin have been characterized in both species. Lysine vasopressin is roughly as abundant as arginine vasopressin. Comparison is made with Australian marsupials Macropodidae and Phalangeridae, and possible evolutionary mechanisms are discussed.

Amino Acids↗
PubMed1985

The nonmammalian-mammalian transition through neurohypophysial peptides.

Neurohypophysial hormones are particularly proper evolutionary tracers. Whereas Eutherian mammals have oxytocin and virtually always arginine vasopressin, nonmammalian tetrapods possess instead mesotocin and vasotocin. The transitions of mesotocin-oxytocin and vasotocin-vasopressin involved in the passage of reptiles-mammals seem to have occurred independently. Australian marsupials are endowed with mesotocin but American marsupials have either oxytocin (South-American opossums) or both oxytocin and mesotocin (North-American opossum). These results suggest that Australian Metatherians have preserved reptilian mesotocin and used it for milk-ejecting function whereas the change mesotocin-oxytocin appeared only in the American line. All marsupials have either arginine vasopressin or lysipressin and phenypressin (Australians) or lysipressin and arginine vasopressin (Americans). It is assumed that the change of vasotocin into arginine vasopressin occurred very early, perhaps in mammal-like reptiles, and duplication of the gene with subsequent mutations has led to the presence of two vasopressin-like peptides in most Metatherians.

Amphibians↗
PubMed1984

Two multigene families for marsupial neurohypophysial hormones? Identification of oxytocin, mesotocin, lysipressin and arginine vasopressin in the North American opossum (Didelphis virginiana).

Oxytocin, mesotocin ([Ile8]-oxytocin), lysipressin ([Lys8]-vasopressin) and arginine vasopressin have been identified in the North American opossum (Didelphis virginiana) by amino acid composition and high pressure liquid chromatography. The same peptides with the exception of mesotocin have previously been found in two South American opossums (Didelphis marsupialis and Philander opossum). Although a dual heterozygocity could also explain the simultaneous presence of oxytocin/mesotocin on one hand, lysipressin/arginine vasopressin on the other, it is assumed, from the results obtained with individual glands of Australian and South American marsupials, that distinct genes encode for the four peptides.

Amino Acids↗
PubMed1984

Divergent neuropeptide evolutionary drifts between American and Australian marsupials.

Present-day marsupials, which are supposed to have arisen from a single stem diverging from the placental stem some 130 million years ago, exist only in the American and Australian continents. Comparison of the homologous genes and their protein products, which evolved under different environmental conditions, may provide arguments for either selective or neutral evolution. In contrast to Australian Macropodidae, which have peculiar neurohypophysial peptides, namely mesotocin and two pressor peptides, lysine vasopressin and phenypressin, the South American oppossum, Didelphis marsupialis, has oxytocin, lysine vasopressin, and arginine vasopressin. Because placental mammals have oxytocin and usually arginine vasopressin, and nonmammalian tetrapods have mesotocin and arginine vasotocin, it is assumed that (1) selective change of arginine vasotocin into arginine vasopressin occurred in mammalian ancestors and a subsequent gene duplication in the marsupial line gave rise to two pressor peptides with divergent neutral drifts in American and Australian groups, and (2) mesotocin of nonmammalian tetrapods has been preserved in Australian marsupials and reclaimed for milk-ejecting function whereas it has been converted into oxytocin in South American oppossums. The change of mesotocin into oxytocin seems neutral rather than selective.

Amino Acid Sequence↗
PubMed1984

Ontogeny of the bovine neurohypophyseal hormone precursors. Foetal neurohormones and neurophysins.

Neurohypophyseal hormones are fragments of precursor proteins that include specific neurophysins and are processed during axonal transport. Neurohormones and neurophysins purified from 7-9 month old bovine foetuses have been characterized by amino acid analysis and partial amino acid sequences. Oxytocin and arginine vasopressin, on one hand, and VLDV-neurophysin and MSEL-neurophysin, on the other, are identical to products previously characterized in the adult. Whereas oxytocin and vasopressin genes seem to be expressed at the same rates in the adult, as judged by the amounts of their peptide products in neurohypophysis, in the late foetus the vasopressin gene appears to be roughly three times more active than the oxytocin gene.

Amino Acid Sequence↗
PubMed1983

The glycopeptide domain of the rat vasopressin precursor.

The vasopressin precursor is composed of 3 domains, namely vasopressin, MSEL-neurophysin and a glycopeptide. Processing occurs during axonal transport from hypothalamus to neurohypophysis from which the 3 fragments can be isolated. The glycopeptide fragment of the rat vasopressin precursor has been purified and sequenced. Despite the fact that rat MSEL-neurophysin is shortened (93 residues instead of 95 for other mammals), rat glycopeptide has 39 residues, as do the other mammalian glycopeptides, suggesting a similar processing. Fifteen substitutions are however observed when compared to ox glycopeptide. The C-terminal part of MSEL-neurophysin (residues 77-93) and the glycopeptide are encoded by the same exon and the homologies when compared with their bovine counterparts are 58% and 62% respectively. In contrast, the central part of rat MSEL-neurophysin (residues 10-76), which is encoded by a separate exon, displays 96% of homology; vasopressin and the N-terminal part of MSEL-neurophysin (residues 1-9), encoded by a third exon, are nearly invariant.

Amino Acid Sequence↗
PubMed1983

A multigene family for the vasopressin-like hormones? Identification of mesotocin, lysipressin and phenypressin in Australian macropods.

Mesotocin ([Ile8]-oxytocin), lysipressin ([ Lys8]-vasopressin) and phenypressin ([Phe8]-vasopressin) have been identified in the western gray kangaroo (Macropus fuliginosus) as well as four other macropodids. Lysipressin and phenypressin, which differ by the amino acids in positions 2 (Tyr/Phe) and 8 (Lys/Arg) are likely products of two separate vasopressin-like genes. It is assumed that arginine vasopressin found in most mammals is the product of two identical genes which can be revealed in some species by differential mutations as seen usually in marsupials. The duality can also be revealed by differential mutations in another domain of the precursors, such as the neurophysin (MSEL-neurophysin), as observed in the ox.

Animals↗
PubMed1983

Identification of mesotocin, lysine vasopressin, and phenypressin in the eastern gray kangaroo (Macropus giganteus).

The neurohypophysial hormones of the eastern gray kangaroo (Macropus giganteus) have been isolated through molecular sieving and paper chromatoelectrophoresis. One oxytocin-like and two vasopressin-like peptides have been found. These peptides have been characterized by amino acid analysis. Mesotocin ([Ile8]-oxytocin), has been identified both by amino acid composition and by behavior in partition chromatography. Lysine vasopressin has been characterized by amino acid composition and by partial amino acid sequence determination. Phenypressin ([Phe2]-arginine vasopressin) has been identified by amino acid composition. Lysine vasopressin is about twice as abundant as phenypressin. These three peptides have previously been identified in two other macropodids, namely, the red kangaroo and the tammar wallaby, and seem to be present in all the family Macropodidae. The evolution of neurohypophysial hormones is discussed in regard to these results.

Amino Acids↗
PubMed1983

Marsupial neurohypophysial hormones: identification of mesotocin, lysine vasopressin, and phenypressin in the quokka wallaby (Setonix brachyurus).

The neurohypophysial hormones of the quokka wallaby (Setonix brachyurus) have been isolated through preparative high pressure liquid chromatography (HPLC). One oxytocin-like and two vasopressin-like peptides have been found. These peptides have been characterized by their amino acid composition and by their retention time in HPLC. Mesotocin ([I1e8]-oxytocin) has been identified by amino acid composition, polar partition chromatography, high pressure liquid chromatography with a reversed phase column, and pharmacological properties. Lysine vasopressin and phenypressin ([Phe2]-arginine vasopressin) have been characterized by amino acid composition, ion-exchange chromatography, and high pressure liquid chromatography. Lysine vasopressin is about twice as abundant as phenypressin. These three peptides have previously been found in three species belonging to the genus Macropus, namely the red kangaroo, the Eastern gray kangaroo, and the tammar wallaby; they are therefore current in the family Macropodidae. Comparison with other native Australian mammals is discussed.

Amino Acids↗
PubMed1983

Identification of human neurophysins: complete amino acid sequences of MSEL- and VLDV-neurophysins.

Two human neurophysins have been purified from acetone-desiccated posterior pituitaries by acidic extraction, molecular sieving, and ion-exchange chromatography. The complete amino acid sequence of each protein has been determined by using a sequencer and characterizing two sets of overlapping enzymic peptides. The two neurophysins belong to two structural families previously defined as MSEL- and VLDV-neurophysins according to the nature of the residues in positions 2, 3, 6, and 7. (MSEL-neurophysins contain methionine-2, serine-3, glutamic acid-6, and leucine-7; VLDV-neurophysins contain valine-2, leucine-3, aspartic acid-6, and valine-7.) Human MSEL-neurophysin has only 93 residues instead of 95 usually found in MSEL-neurophysins from other mammalian species, probably because of a deletion of amino acids 91 and 92. Compared with bovine MSEL-neurophysin, nine variations (seven substitutions and two deletions) are observed. Human VLDV-neurophysin has 93 residues, as do the other mammalian VLDV-neurophysins. There are 11 substitutions when the comparison is made with bovine VLDV-neurophysin. Between the two human neurophysins, there are 26 variations. However, the central parts of the proteins (residues 10-70) are nearly identical. Furthermore, in this region identical substitutions are found in positions 29 and 60 of both neurophysins, suggesting either a single exon or some relationship between the two corresponding genes.

Amino Acid Sequence↗
PubMed1982

Marsupial hypothalamo-neurohypophyseal hormones. The brush-tailed possum (Trichosurus vulpecula) active peptides.

The hypothalamo-neurohypophyseal hormones of the brush-tailed possum (Trichosurus vulpecula) have been purified through molecular sieving and paper chromatoelectrophoresis. Two peptides have been isolated, one with pressor property, the other with uterotonic activity. The pressor hormone has been identified as arginine vasopressin by amino acid composition and amino acid sequence. The oxytocin-like hormone has been characterized as mesotocin by amino acid composition. The amounts per dried neuro-intermediate gland (1.0-1.5 mg) are approximately 12 and 5 nmol, respectively. Up to now, mesotocin has only been found in non-mammalian tetrapods, particularly in reptiles. Its preservation in Australian marsupials (Macropodidae and Phalangeridae), and the replacement of vasotocin by a vasopressin-like peptide, suggests that they are transition species between reptiles and Eutheria. However, the presence of mesotocin raises the question of its role in marsupial lactation.

Amino Acids↗