67 research outputs found
Desempenho agronômico e qualidade de sementes de crambe em diferentes épocas e profundidades de semeadura
Tamanho ótimo de parcela para experimentos com plantas de mamoeiro em casa de vegetação
TAMANHO E FORMA DA UNIDADE AMOSTRAL PARA QUANTIFICAÇÃO DA SERAPILHEIRA EM FRAGMENTO DE FLORESTA ESTACIONAL SUBTROPICAL1
Zur Persönlichkeitsentwicklung bei im Kindesalter beginnenden Epilepsien mit komplex-fokalen Anfällen
Increase in acid phosphatase activity during fertilization of a teleost egg
Acid phosphatase activity was localized at the periphery of the yolk globules in the egg of the teleost, Catostomus commersoni. In addition, a 3-fold increase in acid phosphatase activity was associated with fertilization and pronucleus formation. © 1981 Birkhäuser Verlag
Isoforms of soluble α-tubulin in oocytes and brain of the frog (genus Rana): Changes during oocyte maturation
Rana oocytes have previously been shown to contain much more soluble tubulin than does the brain, suggesting different assembly and disassembly dynamics of frog oocyte tubulin compared to that in brain. By using centrifugation, SDS-PAGE, two-dimensional gel electrophoresis and Western blots, probed with anti-α-tubulin monoclonal antibodies, polymorphic α-tubulins (isoforms) were compared in brains and follicle-enclosed oocytes of northern (Rana pipiens) and southern (R. belandieri) frogs. Oocyte tubulin in both species had isoforms with greater ranges of isoelectric point (pI) than those of brain tubulins; in particular, the oocyte tubulin pIs ranged further into the acidic region of the isoelectric-focusing gels than corresponding brain tubulin. This difference may, in part, be responsible for the previously reported assembly differences between oocyte tubulin (undetectable assembly) and brain tubulin (high assembly). Isoforms of α-tubulin with relatively acidic pI were more abundant in northern frog brain and oocyte soluble extracts than in analogous extracts from southern frogs. Furthermore, additional acidic α-tubulin isoforms were found in progesterone-treated oocytes (i.e., eggs), indicating increased heterogeneity of acidic α-tubulin isoforms during oocyte meiotic maturation. Among northern frog oocyte soluble components fractionated on Superose-6b columns, tubulin complexes with apparent molecular mass of about 1800 kDa were found to contain acidic α-tubulin isoforms while the putative oligomeric tubulins with an apparent molecular mass of about 250 kDa contained an additional relatively basic α-tubulin isoform. The acidic α-tubulin isoforms, therefore, are proposed to be associated with cold-adaptable cells of brain and oocytes, and may also be involved in stabilization of large soluble tubulin complexes in oocytes of the northern frog
Flight enhances juvenile hormone inactivation in Danaus plexippus plexippus L. (Lepidoptera: Danaidae)
Adult Monarch butterflies injected with3H-juvenile hormone (JH) showed a significant increase in haemolymph JH metabolites after a 40 min flight compared to unflown controls. In addition, haemolymph enzymatic JH metabolism was shown to increase with thoracic temperature increases previously shown to be associated with flight. © 1981 Birkhäuser Verlag
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