Zur Wirkung des Juvenilhormons: Elektrophysiologische Messungen an der Zellmembran der Speicheldrüse von Galleria mellonella

Baumann, Gilbert

doi:10.1016/0022-1910(68)90179-0

Cited by 47 publications

(3 citation statements)

References 25 publications

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“…Measurements of the electropotential difference between the intranuclear and extracellular fluid of salivary glands indicate that variations in the nuclear Na+/K+ ratio do in fact occur during normal development, as well as after experimental hormone administration; juvenile hormone would shift this ratio up and ecdysone would shift it down (BAUMANN, 1968;KROEGER, 1966). Both these ions are probably always present together, although in different ratios.…”

Section: Ionic Milieu In the Cell Nucleus And Iis Variationmentioning

confidence: 99%

Developmental Studies on Giant Chromosomes

1972

Results and Problems in Cell Differentiation

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specifically those of translation, reprinting, re-use of illustrations, broadcasting, reproduction by photocopying machine or similar means, and storage in data banks. Under § 54 of the German Copyright Law where copies are made for other than private usc, a fee is payablo to the publisher, the amount of the fee to be determined by agreement with the publisher.The use of general descriptive names, trade names, trade marks ete. in this publication, cven if the former are not especially identified, is not to be raken as a sign that such names, as undcrstood by thc Tradc Marks and Merchandise Marks Act, may accordingly be used frcely by anyone.So great was the impact of the "rediscovery" of poly te ne chromosomes on the genetic study of Drosophila that MORGAN, BRIDGES, and SCHULTZ began their 1935-1936 report to the Carnegie Institute of Washington with the words:"During the past two years the emphasis in the Drosophila work has shifted from analysis by breeding methods to analysis by cytological observations".T. H. MORGAN had returned to embryological studies, interrupted 25 years earlier by Drosophila, and the report was a summary of the work of the other two authors. CA LV IN BRIDGES was preparing detailed chromosome maps and cataloging the breakpoints of genetically known chromosome re arrangements in order to correlate his genetic maps with the new cytological ones. ]ACK SCHULTZ, among other projects, continued his studies on position-effect variegation. He noted variegation of the morphology of the salivary gland chromosome regions known to contain the genes for which mottled effects had been observed.Polytene chromosomes continued to play a prominent role in ]ACK'S thoughts and work for the rest of his life. Thirty years later in the 1965 Brookhaven Symposium we find original work supporting the earlier view that variegation resulted from the inactivation of genes in some cells but not others during development: in this case the development of a puff served as the indicator of activity. The intervening years had included a variety of studies aimed at understanding the phenomenon in terms of the regulation of the synthesis of nucleic acids, beginning in an era when proteins were known to have the range of specificities required of the genetic material.But personal involvement in experimental work directly concerned with polytene chromosomes does not reflect the extent of his influence on matters discussed in this volume, namely the nature and function of the genetic material. His most important writings were preparations of critical analysis of data at hand (of which the 1965 symposium paper was the last and one of the best), indicating where evidence was strong and where weak, but, most important, drawing on a wealth of disciplines varied enough to avoid pitfalls so often associated with "specialization". It was the analysis that appealed to hirn and that he offered; those who looked to his writings for answers were sometimes disappointed by a carefully worded statement balancing VI Jack Schultz evidence ag...

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Section: Ionic Milieu In the Cell Nucleus And Iis Variationmentioning

confidence: 99%

Developmental Studies on Giant Chromosomes

1972

Results and Problems in Cell Differentiation

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“…This supposition is supported by the labeling ratios of BR1: BR2 where the controls are as low as 0.25 and the ecdysone treated animals as high as 1.4 (average values in Table 2). This enhancement of BR1 activity by ecdysone may result in a significant change in the nuclear RNA complement since it may be responsible for [10][11][12][13][14][15][16][17][18][19][20] per cent of the non-nucleolar RNA in the salivary gland nucleus. Although the activity of BR3 is also enhanced by ecdysone, the absolute increase is much less (3-6% of the non-nucleolar RNA) than that observed with BR1 (Table 2).…”

Section: Ib)mentioning

confidence: 99%

“…However, ecdysone appears to increase the K+/Na+ ratio in intact salivary glands,19 whereas juvenile hormone appears to decrease this ratio. 20 Puff formation or Balbiani ring enlargement at the ecdysone-specific loci I-18-C, IV-2-B, and BR1 can be induced by incubating isolated nuclei in a medium rich in K+, whereas the juvenile hormone-specific puff can be elicited by incubating isolated nuclei in a Na+ rich medium.13' 21 Recent experiments with both isolated chromosomes and chromatin suggest that K+ and Na+ interact with the histone-DNA bonds and that their specificity depends on the presence of bivalent cations.2'…”

Section: Ib)mentioning

confidence: 99%

CONTROL OF GENE ACTIVITIES IN THE POLYTENE CHROMOSOMES OF Chironomus tentans BY ECDYSONE AND JUVENILE HORMONE

Lezzi

Gilbert

1969

Proc. Natl. Acad. Sci. U.S.A.

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Abstract.-The injection of ecdysone (molting hormone) into chironomid larvae is known to result in the stimulation of specific gene activities (increased RNA synthesis). The morphological manifestation of this gene activation is the formation of a puff. Cytological and autoradiographic analysis of several regions of the salivary gland chromosomes of Chironomus tentans revealed that ecdysone also stimulates Balbiani ring 1. In contradistinction to the puffs, the Balbiani rings are tissue specific and account for a significant percentage of the cell's non-nucleolar RNA.The application of juvenile hormone results in a decreased activity of Balbiani ring 1, suggesting that the two hormones may act antagonistically. In addition, juvenile hormone induces a puff at chromosome region I-19-A and this puff becomes less active after a short-term treatment with ecdysone. These data demonstrate an effect of juvenile hormone on puffing and are the first to demonstrate activation of a Balbiani ring by ecdysone.The original and important observation that the insect molting hormone, ecdysone, can influence the activity of two specific loci on the polytene, salivary gland chromosomes of larval Chironomus tentans, was made a decade ago by Clever and Karlson.I In that case, injection of ecdysone stimulated the formation of puff 1-18-C and caused the regression of puff 1-19-A. This finding, as well as subsequent work on the polytene chromosomes of Diptera, led to the conclusion that ecdysone acts either directly upon the chromosome or indirectly via changes in the ionic environment.2In regard to salivary gland function, however, the activation or deactivation of a puff-forming region can be considered a minor effect since a puff only constitutes between 0.5 to 3.0% of the total non-nucleolar RNA in the salivary gland nucleus.3 4 In addition, the puffs alluded to above1 are not specific to the salivary gland chromosomes.5 The Balbiani rings (BR1, BR2, BR3), on the other hand, are considered to be sites of gene activity specific to the salivary gland chromosomes6 and produce 10-60 times more RNA than a puff.3' 4 The present paper describes the effect of ecdysone on Balbiani ring 1.

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Electrical properties of developing oocytes of the migratory locust, Locusta migratoria

Wollberg¹,

Cohen²,

Kalina³

1976

Journal Cellular Physiology

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The electrical properties of developing nonfertilized oocytes of Locusta migratoria were studied, using intracellular microelectrodes. The inseries potential of the combined oomembrane and of the follicular cells was about 20 mV in the youngest oocytes. It increased as the oocytes developed and it reached a plateau of about 50 mV before full maturation, generally four to seven oocytes away from the fully-developed terminal oocyte. Current-voltage relations were always linear for hyperpolarizing currents. Most oocytes exhibited, however, rectification to outward current. Input resistance values varied with oocyte size from about 5 X 10(6) ohm for young oocytes to about 0.2 X 10(6) ohm for the more developed ones. Some oocytes displayed a transient depolarization on turning off a hyperpolarizing step of current. This depolarization was not correlated with the size of the oocyte or with any observed morphological feature. Any two adjacent oocytes were electrotonically coupled. A single ovariole thus represented a longitudinal chain of developing oocytes which were connected electrically. This was supported by electron microscope observations which revealed junctions partially impermeable to lanthanum and gap junctions between the follicular cells themselves and between follicular cells and oocytes. The coupling coefficient was dependent on the direction of current flow. The attenuation of voltage along an ovariole was always greater at the distal than at the proximal side.

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Zur Wirkung des Juvenilhormons: Elektrophysiologische Messungen an der Zellmembran der Speicheldrüse von Galleria mellonella

Cited by 47 publications

References 25 publications

Developmental Studies on Giant Chromosomes

Developmental Studies on Giant Chromosomes

CONTROL OF GENE ACTIVITIES IN THE POLYTENE CHROMOSOMES OF Chironomus tentans BY ECDYSONE AND JUVENILE HORMONE

Electrical properties of developing oocytes of the migratory locust, Locusta migratoria

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