Amino acid sequence of the nonsecretory ribonuclease of human urine

The amino acid sequence of a nonsecretory ribonuclease isolated from human urine was determined except for the identity of the residue at position 7. Sequence information indicates that the ribonucleases of human liver and spleen and an eosinophil-derived neurotoxin are identical or very closely related gene products. The sequence is identical at about 30% of the amino acid positions with those of all of the secreted mammalian ribonucleases for which information is available. Identical residues include active-site residues histidine-12, histidine-119, and lysine-41, other residues known to be important for substrate binding and catalytic activity, and all eight half-cystine residues common to these enzymes. Major differences include a deletion of six residues in the (so-called) S-peptide loop, insertions of two, and nine residues, respectively, in three other external loops of the molecule, and an addition of three residues at the amino terminus. The sequence shows the human nonsecretory ribonuclease to belong to the same ribonuclease superfamily as the mammalian secretory ribonucleases, turtle pancreatic ribonuclease, and human angiogenin. Sequence data suggest that a gene duplication occurred in an ancient vertebrate ancestor; one branch led to the nonsecretory ribonuclease, while the other branch led to a second duplication, with one line leading to the secretory ribonucleases (in mammals) and the second line leading to pancreatic ribonuclease in turtle and an angiogenic factor in mammals (human angiogenin). The nonsecretory ribonuclease has five short carbohydrate chains attached via asparagine residues at the surface of the molecule; these chains may have been shortened by exoglycosidase action.(ABSTRACT TRUNCATED AT 250 WORDS)     

Comparative studies of the vascular system of node-leaf continuum in woody ranales

The vascularization of the node-leaf continuum in the first to eighth foliage leaves of the first-year plant ofMagnolia virginiana is investigated. The cotyledonary node is a 4-trace, 3-lacunar type. Vascularization in the cotyledonary node is fundamentally different from that in the folair node of the same plant. As a result, the cotyledonary vascularization is only described but not compared to that in the foliar node-leaf continuum. Considerable diversity occurs in the node-leaf vascularization of the first-year plants. A 5-trace, 4-lacunar vascular system is constant in the lower folair nodes; this is considered to be the fundamental vascular pattern in the node-leaf continuum of the species. In contrast, the nodal anatomy and petiolar vascularization fluctuate widely in the third to eighth leaves of the first-year plants. Variation is found not only between different nodes of a single plant but even in the corresponding nodes of different individuals. The evidence clearly indicates that variation always correlates with certain members of the leaf-trace complement; thus, either the ventral and/or marginal lateral bundles undergo phylogenetical reduction or amplification.     

Tool-use for catching ants by chimpanzees at Bossou and Monts Nimba,West Africa

The use of tools by wild chimpanzees to catch ants was studied at Bossou and Monts Nimba, south-eastern Guinée. Insect-eating by chimpanzees at Bossou appears to be opportunistic and ant-catching was seen only in certain years. The most common prey species wasDorylus (Dorylus) molestus Gerstaecker. Sixty wands for catching ants were found at Bossou. Half of them were made from Zingiberaceae or Marantaceae, the stems and long petioles of which are usually straight, and have few branches. The length of the wand was variable. The mean length of ant-catching wands (46.7 cm) was between those found at Gombe and Tai. Ants' nests were usually dug up by hand, but on one occasion a digging stick was used. Four chimpanzees who used only one hand to manipulate the wand had also been observed using a stone hammer for nut-cracking. All of them used the same hand in wand-manipulation as in nut-cracking. As reported for chimpanzees at Gombe, Mahale, and Tai, more females than males tended to catch ants with wands though the sex difference was not demonstrated statistically. Ants which climbed up the wand were directly squeezed off using the lower-lip and eaten. This is the same method as seen at Tai, but different from most episodes observed at Gombe. Juveniles and infants also caught ants using wands, however, they seemed to do this more out of curiosity than as a means of feeding. At Goera, over 15 km from Bossou and separated from it by Monts Nimba, the same characteristics of ant-catching techniques were evident from traces.