Assuntos
Anticorpos Monoclonais/metabolismo , Núcleo Celular/metabolismo , Citoesqueleto/metabolismo , Células Germinativas/metabolismo , Microtúbulos/metabolismo , Fosfoproteínas/metabolismo , Núcleo Celular/genética , Imunofluorescência , Células Germinativas/citologia , Meiose/genética , Meiose/fisiologia , Microtúbulos/genética , Fosfoproteínas/genética , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Solanum , Fuso Acromático/genética , Fuso Acromático/metabolismoRESUMO
Neuropeptides are the key molecules in a multiplicity of physiological processes and their use in pest control has recently been suggested. Most neuropeptides are produced in the form of a precursor that is cleaved by proteolysis to yield various biologically active peptides. To mimic this structure, a method has been developed for synthesizing genes that code for putative polyneuropeptide precursors. As a model neuropeptide, the 5-amino-acid proctolin, one of the best studied invertebrate neuropeptides, functioning both as a visceral and a skeletal neuromuscular transmitter, was chosen. The synthetic gene was introduced into bacteria and tobacco plants, where it was efficiently transcribed. We present our results as a possible approach for the expression, in a variety of organisms, of synthetic genes coding for a wide repertoire of insect neuropeptides.
Assuntos
Genes de Protozoários/genética , Controle de Insetos/métodos , Neuropeptídeos/genética , Nicotiana/genética , Oligopeptídeos/genética , Plantas Tóxicas , Engenharia de Proteínas/métodos , Precursores de Proteínas/genética , Transfecção/métodos , Sequência de Aminoácidos , Vetores Genéticos/genética , Dados de Sequência Molecular , Neuropeptídeos/metabolismo , Oligopeptídeos/metabolismo , Precursores de Proteínas/metabolismo , Nicotiana/metabolismoRESUMO
Macrosporogenesis and microsporogenesis were investigated in a diploid S. tuberosum x S. chacoense potato hybrid, characterized by more than 50% 2n egg formation. Fifty-five percent of dyad formation of 2n macrospores is ascribed to two meiotic abnormalities: omission of the second meiotic division, occurring at a frequency of 38%, and irregular spindle axis orientation at metaphase I at a frequency of 16%: These abnormalities give origin to a mixture of 2n eggs, composed of mostly second division restitution (SDR) and a small portion of first division restitution (FDR). Microsporogenesis showed rare dyads of 2n microspores depending on parallel spindles observed in anaphase II.
RESUMO
Eight near-isogenic lines of pea representing all the homozygous combinations of three genes af, st and tl, which modify leaf shape and size, were crossed in all possible ways excepting reciprocals. An analysis of the resulting 36 families has shown that homozygous mutant alleles at the tl locus acting with homozygous mutant alleles at the af and st loci increase both seed weight and plant haulm weight. The mutant alleles at the af and st loci seem, when homozygous, to have little effect by themselves upon seed weight but they do increase or decrease haulm weight, respectively. There is clear evidence of heterotic effects resulting from heterozygosity at each one of the three loci which modify seed weight, haulm weight and basal branching. The implications of such heterotic effects in pea breeding programmes are discussed.
RESUMO
The effects of three genes (af, st and tl) which modify leaf and stipule form and size in peas were investigated in families generated by crossing eight near-isogenic lines in all combinations but excluding the reciprocals. The eight parents and their equivalent phenotypes differed significantly for all characters due to the direct effects of all three genes, with their combined effects being especially influential in some instances. The effects of the recessive allele at any one of the three loci in homozygotes was to reduce plant productivity with stst having the most pronounced effect. The response of characters tended to be similar in direction, if not in magnitude, to any of the three genes. Partial dominance was frequently associated with the tl locus, and was especially obvious in afaf Tltl genotypes.
RESUMO
After diethylsulphate treatment of seeds of the pea variety 'Parvus', a new floral mutation was isolated in the second generation. This mutation, named stamina pistilloida, is characterized by a partial fusion of the androecium with the gynoecium; the two marginal stamens of the staminal column are transformed in rudimentary carpels more or less differentiated according to ecoclimatic conditions. The genetic analysis has shown the monogenic and recessive behaviour of the mutation (gene proposed stp) and its linkage with the gene oh in the chromosome II.
