ABSTRACT The Mylodontidae Scelidotheriinae (Mammalia, Xenarthra, Tardigrada) are a diversified clade of South American fossil ground sloths, with a wide geographic distribution, especially in high and middle latitudes. According to the last revision, the Quaternary diversity includes the genera Scelidotherium, Catonyx, and Valgipes. The clade Scelidotheriinae is well represented in the Pleistocene of the Tarija-Padcaya basin, and the first mention of these ground sloths correspond to the middle of the XIX Century. Since then, several species (i.e., Scelidotherium tarijensis, Scelidodon tarijensis, Scelidotherium capellini) have been reported as inhabiting the Tarija-Padcaya basin during the Pleistocene. Despite the abundance of fossil records of Scelidotheriinae in this area, no modern taxonomic revisions are available. In consequence, in this contribution a revision of the remains assigned to Scelidotheriinae from the Tarija-Padcaya basin is accomplished, and some biostratigraphic and geographic implications are discussed. Our results show that one single species (Catonyx tarijensis) can be recognized in the studied area, whereas a supposed smaller one (Scelidotherium patrium) actually corresponds to juvenile specimens of C. tarijensis.

Abstract Urease catalyzes the hydrolysis of urea to ammonia and carbon dioxide. The ammonia (nitrogen (N) product of urease activity) is incorporated into organic compounds. Thus, urease is involved in N remobilization, as well as in primary N assimilation. Two urease isoforms have been described for soybean: the embryo-specific, encoded by the Eu1 gene, and the ubiquitous urease, encoded by Eu4. A third urease-encoding gene was recently identified, designated Eu5, which encodes the putative protein product SBU-III. The present study aimed to evaluate the contribution of soybean ureases to seed germination and plant development. Analyses were performed using Eu1/Eu4/Eu5-co-suppressed transgenic plants and mutants of the Eu1 and Eu4 urease structural genes, as well as a urease-null mutant (eu3-a) that activates neither the ubiquitous nor embryo-specific ureases. The co-suppressed plants presented a developmental delay during the first month after germination; shoots and roots were significantly smaller and lighter. Slower development was observed for the double eu1-a/eu4-a mutant and the eu3-a single mutant. The N content in transgenic plants was significantly lower than in non-transgenic plants. Among the mutants, eu3-a presented the lowest and eu1-a the highest N content. Altogether, these results indicate that increased ureolytic activity plays an important role in plant development.

Frações protéicas obtidas de sementes de feijão-de-porco (Canavalia ensiformis), bem como o aminoácido canavanina presente nestas sementes, foram avaliadas em sua capacidade de inibir o crescimento dos fungos fitopatogênicos Macrophomina phaseolina, Colletotrichum gloesporioides, Sclerotium rolfsii e Fusarium oxysporum. Constatamos que a maior parte das proteínas examinadas e também canavanina não apresentaram nenhum efeito sobre o crescimento desses fungos. Por outro lado, a proteína tóxica canatoxina mostrou-se efetiva, a uma concentração de 2%, na inibição do crescimento de M. phaseolina, C. gloesporioides e S. rolfsii.

Protein fractions obtained from seeds of the jack bean (Canavalia ensiformis) as well as the amino acid canavanine, present in these seeds, were tested for their capacity to inhibit the growth of the phytopathogenic fungi Macrophomina phaseolina, Colletotrichum gloesporioides, Sclerotium rolfsii and Fusarium oxysporum. We found that most of the proteins examined and also canavanine did not have any effect on the growth of these fungi. On the other hand the toxic protein canatoxin was found to be effective, at a concentration of 2%, in the inhibition of the growth of M. phaseolina, C. gloesporioides and S. rolfsii.