摘要:

AbstractA series of experiments are presented that have been performed to observe the interactions betweenAgrobacterium tumefaciensstrains mutated in the T‐DNA genes involved in indoleacetic acid and cytokinin biosynthesis and severalNicotianaspecies and hybrids. Infections were induced on leaf cuttings ofNicotiana debneyi, N. knightiana, N. clevelandii, N. bigeloviivarbigelovii, N. bigeloviivarquadrivalvis, N. glauca, N. langsdorffii, the amphidiploid tumorous hybridN. glauca×N. langsdorffii, and a nontumorous mutant of it. The effect of deletions of the Ti plasmid varied according to plant genotype. Insertion mutants iniaaMandiaaHsuppressed tumor formation inN. langsdorffii, reduced it inN. bigeloviivarquadrivalvis, had no effect inN. glaucaand the two amphidiploid hybrids, and promoted tumorigenesis when compared to the wild‐typeAgrobacteriumstrain B6S3 inN. bigelovii N. debneyi, andN. knightiana.The same mutations induced shoot formation inN. glauca, increased it inN. debneyi, and suppressed root formation inN. knightiana.On the other hand, an insertion mutation of the isopentenyl transferase gene(ipt‐)had no effect inN. bigeloviivarquadrivalvis, N. debneyi, the tumorous hybrid, suppressed tumor formation inN. langsdorffii, and inhibited it inN. glauca, the nontumorous hybrid,N. bigeloviivarbigelovii, andN. knightiana.Insertion iniptsuppressed shoot formation in the nontumorous hybrid and inhibited it in the nontumorous amphidiploid andN. debneyi, while promoting root formation inN. glaucaandN. debneyi.The suggestion of the existence of specific hormone equilibria necessary for the shift to each morphogenetic pattern was supported by experiments with exogenous hormone treatments of three genotypes(N. glauca, N. langsdorffii, and the nontumorousN. glauca×N. langsd

ISSN:0192-253X    

DOI:10.1002/dvg.1020080202

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1987

数据来源: WILEY

摘要:

AbstractThe amount of cytosolic glucocorticoid receptor in liver of Ts18, Tsl6, and Tsl9 vs euploid mouse fetuses was studied after incubation of [3H]dexamethasone with cytosol followed by isoelectric focusing on polyacrylamide gels. In addition, corticosterone concentrations and enzyme activities of alanine aminotransferase and tyrosine aminotransferase were measured in the cytosol of the livers. The amount of glucocorticoid receptor in the cytosol fractions of the livers was always higher in the Tsl8 than in the euploid fetuses of the same litter. It was also significantly (P<0.0005) higher if pooled data from different litters were analyzed. The ratio of the glucocorticoid receptor in Ts l8 vs euploid mice varied between 1.3 and 4.7, with a mean of 2.1. In contrast, the glucocorticoid receptor levels in Tsl6 and Tsl9 fetuses were not different from the corresponding euploid controls. Comparing the corticosterone levels of the three trisomies tested with the corresponding euploid fetuses, no significant differences were found, indicating that the markedly elevated cytosolic glucocorticoid receptor concentrations in Tsl8 were not due to different corticosterone levels. This finding is consistent with the assignment of the glucocorticoid receptor gene to chromosome 18 in the mouse. There was no correlation betwen glucocorticoid receptor levels and the activity of the two glucocorticoid inducible enzymes tested in the liver of mouse fetuses.

ISSN:0192-253X    

DOI:10.1002/dvg.1020080203

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1987

数据来源: WILEY

摘要:

AbstractInteraction between the epiblast and the primary hypoblast in chick blastula results in induction of the primitive streak (PS) in the epiblast. Alpha‐amanitin, a specific inhibitor of poly A‐containing RNA synthesis, inhibits formation of the definitive PS. This inhibition is associated with qualitative changes in the pattern of protein synthesis in the hypoblast but not in the epiblast. The protein pattern of the component areas of the epiblast shows increase in some polypeptides after treatment with α‐amanitin. By contrast, α‐amanitin resulted in a decrease in synthesis of several polypeptides, which are either undetectable or weakly present in the hypoblast. The α‐amanitin‐sensitive translational products of the embryonic genome that are observed in the hypoblast may have specific functions in the control of PS induction and

ISSN:0192-253X    

DOI:10.1002/dvg.1020080204

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1987

数据来源: WILEY

摘要:

AbstractTo elucidate the mechanisms whereby genes and environment influence wing size, we investigated the effects of various rearing temperatures and larval crowding conditions on the wings of the mutantminiatureand wild‐type fruit flies. In adults we monitored wing size, cell number, wing thickness, cell density; in larval imaginal discs we looked for cell death. Cell density was inversely proportional to wing size. Of particular interest was the finding that smaller wings tend to be thicker. Electron microscope studies showed that theminiaturewing layers are grossly abnormal. We hypothesize that these abnormalities are due to abnormal cell flattening of the wing epithelial cells, and we conclude that gene and environmental effects on cell flattening may be an important component in determining cell density and hence organ siz

ISSN:0192-253X    

DOI:10.1002/dvg.1020080205

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1987

数据来源: WILEY

摘要:

AbstractThe epidermis of Drosophila has a tissue polarity that is manifested by a parallel array of polarized structures (primarily hairs and bristles). The production of normal tissue polarity requires the function of thefrizzled(fz) locus. We have isolated a large number of alleles at this locus and have phenotypically characterized more than 25 of them. We have found extensive allelic variation that a previous study failed to detect. Most of the alleles fall into a hypomorphic to amorphic series. Two alleles, however, have unusual properties. These alleles, which in general are moderately strong alleles, fail to produce a rough eye phenotype that is characteristic of all the other moderate or strongfzalleles. Thus, these two alleles are tissue specific in effect. Furthermore, these two alleles also have a neomorphic or antimorphic effect on hair polarity in one region of the wing.

ISSN:0192-253X    

DOI:10.1002/dvg.1020080206

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1987

数据来源: WILEY

ISSN:0192-253X    

DOI:10.1002/dvg.1020080207

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1987

数据来源: WILEY

ISSN:0192-253X    

DOI:10.1002/dvg.1020080208

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1987

数据来源: WILEY

ISSN:0192-253X    

DOI:10.1002/dvg.1020080201

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1987

数据来源: WILEY