Diet and seed dispersal potential of the white-lined bat,Platyrrhinus lineatus (E. Geoffroy, 1810), at a site in northeastern Brazil

This study provides insights into the dispersal potential of Platyrrhinus lineatus and its role in habitat regeneration. The study site was an urbanized area in northeastern Brazil. Fecal samples were collected at the roost of a colony during 13 months. Seven species were present in the samples, three of which were exotic. Cecropia glaziovii, Solanum stipulaceum and Coccothrinax barbadensis predominated in the diet of the colony. The large numbers of seeds of pioneer species, and the exotic species present in the diet of the colony emphasize the role of P. lineatus in the regeneration of habitats, and its ecological flexibility.     

ISOLATION OF NITROSOGUANIDINE-INDUCED CHLORELLA VULGARIS MUTANTS WITH HIGH METHIONINE CONTENT1

Mutants of Chlorella vulgaris induced by N-methyl-N′-nitro-N-nitrosoguanidine (NG), and, selected for the resistance to either ethionine or 6-methylpurine, were tested for the relative rate of incorporation into protein of ³H-methionine and ¹⁴C-leucine. A highly significant, correlation between the ³H-to-¹⁴C ratio in the protein and its methionine content was found. 6-Methylpurine proved to be more effective than ethionine as a screening agent for high methionine strains. Screening for 6-methylpurine resistance, followed by a second screening for the highest methionine-to-leucine incorporation ratio, led to isolation of the mutants with a content up to 45% higher in methionine and up to 3 times higher in cysteine with respect to the wild strain.     

Structure and absolute stereochemistry of vanillosmin,a guaianolide from Vanillosmopsis erythropappa

The structure and absolute stereochemistry of vanillosmin were established by chemical and spectral evidence and by comparison with O-acetyl-isophoto-α-santonic lactone and tetrahydroartabsin “C”.     

Extraction and partial characterization of cellulases from expanding pea epicotyls

Etiolated pea (Pisum sativum) epicotyls synthesize a buffer-soluble cellulase (cellulase A) and a salt-soluble cellulase (cellulase B) (EC 3.2.1.4) after treatment with high (0.5%) auxin levels. Only cellulase A increased in activity after treatment with low (0.005%) auxin. Cellulase A was released into the supernatant after homogenization of tissue in dilute buffer (buffer-soluble), had a pH optimum at 5.5, was relatively thermostable, and its activity was inhibited by NaCl. Cellulase B was released by 1 m NaCl (salt-soluble) from excised tissue segments or from the insoluble residue remaining after removal of the buffer-soluble form. It had a pH optimum at 7.0, was thermolabile, and required salt for maximum activity. When subjected to polyacrylamide gel electrophoresis, the cellulase fraction released by NaCl from excised segments showed two bands of cellulase activity compared to several for the buffer-soluble fraction. Electrophoretic analysis of the buffer and salt-soluble fractions for marker enzymes indicated the presence of malate dehydrogenase activity in all fractions and glutamate dehydrogenase activity in the buffer-soluble fraction only.