University of Port Elizabeth

About: University of Port Elizabeth is a based out in . It is known for research contribution in the topics: Population & Estuary. The organization has 1067 authors who have published 1538 publications receiving 38560 citations. The organization is also known as: UPE & Universiteit van Port Elizabeth.

A method for monitoring mangrove harvesting at the Mngazana estuary, South Africa

Abstract: The Mngazana estuary supports the third largest area of mangroves, and probably the largest stand of Rhizophora mucronata Lamk., in South Africa. The objective of this study was to determine the extent of harvesting in the Mngazana mangrove forest, using available aerial photographs and ground surveys. At 19 sites where harvesting was evident the number of juveniles, adults and stumps were counted in three replicate 25m2 quadrats. GIS was used to generate maps, which indicated that approximately 80% of the mangrove forest showed signs of medium to high harvesting intensity, and that harvesting was taking place in easily accessible areas, especially where Rhizophora mucronata was the dominant species. The ESRI ArcMap density function was used to illustrate the number of harvested stumps and adults within a specific area. GIS analyses classified the mangrove area according to three harvesting intensity classes: low intensity with a ratio of adults to stumps of 2:1, medium intensity 1:1 and high intensity 1:...

Ostrich MSEL-neurophysin belongs to the class of two-domain "big" neurophysin as indicated by complete amino acid sequence of the neurophysin/copeptin.

Abstract: Mammalian neurohypophyseal hormones, oxytocin and vasopressin, are known to be synthesized as part of two larger precursors containing, respectively, a VLDV-neurophysin and a MSEL-neurophysin together with its associated glycopeptide. Starting from ostrich neurohypophyses, a "big" neurophysin was isolated and chemically characterized. Following sequence determination of the CNBr-derived fragments and of peptides obtained from trypsin and V8-protease digestion of the oxidized protein, this "big" neurophysin was found to contain an MSEL-neurophysin moiety (94 residues) still covalently associated with the COOH-terminal glycopeptide (38 residues, copeptin). This study demonstrates that the ostrich MSEL-neurophysin sequence closely resembles all known MSEL-neurophysin sequences and that, furthermore, it does not contain the single amino acid insertion shown previously in the ostrich VLDV-neurophysin. It is also shown that the stretch of amino acids, linking the MSEL-neurophysin and the copeptin, is clearly different from its mammalian homologues and lacks the Arg residue normally recognized by the cleaving enzyme. This study also demonstrates that the ostrich copeptin is more closely related to the amphibian copeptin sequence than to its mammalian homologue, leading to the hypothesis that two families of copeptin molecules might exist. Thus, the ostrich MSEL-neurophysin-copeptin molecule is the first "big" neurophysin reported in birds and, together with the guinea pig and amphibian homologues, represents the third example of partial or no neurophysin-copeptin cleavage.