Selective stimulation of puffing activity in vitro with a juvenile hormone analogue by polytene chromosomes in the salivary glands of Chironomus thummi (Diptera)

1989 ◽  
Vol 67 (10) ◽  
pp. 2528-2532
Author(s):  
X. Vafopoulou ◽  
C. G. H. Steel ◽  
H. Laufer
Keyword(s):  
Juvenile Hormone ◽  
Salivary Glands ◽  
Polytene Chromosomes ◽  
Hormone Analogue ◽  
Juvenile Hormone Analogue ◽  
Balbiani Rings ◽  
Chironomus Thummi ◽  
Stimulation Of

Salivary glands of Chironomus thummi prepupae were treated in vitro with various concentrations of the juvenile hormone analogue (JHA) methoprene and the puffing activities of Balbiani rings (BR) b and c were scored in cytological preparations of polytene chromosomes. In control cultures, both BRb and BRc regress rapidly. JHA treatment in vitro prevented regression at both these sites. In addition, BRb was found to expand within 60 min to a size two to three times larger than in control contralateral glands. The most effective concentration for stimulation of BRb and BRc in vitro was 10−7 M. In vivo treatment of prepupae with 10−7 M JHA also induced puffing activity in BRb and BRc to a degree similar to that observed following in vitro treatment. It is concluded that BRb, and perhaps also BRc, are juvenile hormone (JH) inducible chromosomal sites in Chironomus thummi salivary glands. This is the first report of chromosomal sites that are stimulated by JH in vitro in the absence of exogenous ecdysteroids. These findings support the view that JH may act at the gene level at separate loci from ecdysone.

Aufnahme von 22Na in die Zellkerne der Speicheldrüsen von Chironomus thummi

1966 ◽  
Vol 21 (3) ◽  
pp. 274-277 ◽  
Author(s):  
Markus Lezzi ◽  
Heinrich Kroeger
Keyword(s):  
Salivary Glands ◽  
Polytene Chromosomes ◽  
Inorganic Ions ◽  
Saturation Curve ◽  
Cell Nuclei ◽  
Chironomus Thummi ◽  
In Vitro Uptake

The in vivo and in vitro uptake of 22Na from the hemolymph into cell nuclei of larval salivary glands was measured and compared. The uptake of 22Na in vivo follows approximately a saturation curve. The respective in vitro curve has a much steeper slope during the first 8 min and this phase is followed by an interval during which the 22Na content of the nuclei decreases (8 to 16 min). After the 16th min it increases again to reach a nuclear 22Na content approximately twice as high as that of nuclei in vivo at 60 minutes. The uptake curves are discussed in relation to recent findings on the induction of puffs in polytene chromosomes by inorganic ions.

Die Epidermis von Tenebrio molitor L. Puppen als Zielorgan für das Juvenilhormonanaloge 10.11-Epoxy-6.7-trans-2.3-trans-farnesylpropenyläther / The Epidermis of the Pupae of Tenebrio molitor L. as Target Organ for the Juvenile Hormone Analogue 10,11-Epoxy-6,7-trans-2,3-trans-farnesylpropenylether

1973 ◽  
Vol 28 (3-4) ◽  
pp. 173-177 ◽  
Author(s):  
Peter Schmialek ◽  
Marina Borowski ◽  
Astrid Geyer ◽  
Verena Miosga ◽  
Michael Nündel ◽  
...  
Keyword(s):  
Juvenile Hormone ◽  
Concentration Gradient ◽  
Tenebrio Molitor ◽  
Target Organ ◽  
Hormone Analogue ◽  
Juvenile Hormone Analogue ◽  
Target Organs ◽  
Metabolic Products ◽  
In Vivo Tests

In vivo tests give evidence that the epidermis is the target organ for the juvenile hormone of insects. A study of the distribution of injected 10,11-epoxy-6,7-trans-2,5-trawi-farnesyl-propenylether and of its metabolic products in epidermis, lymphae, and other organs demonstrated that the unaltered ether accumulates in the epidermis against a concentration gradient and is more slowly metabolised there than in the non-target organs.

Ecdysone-regulated chromosome puffing in the salivary glands of the Mediterranean fruit fly, Ceratitis capitata

Genome ◽  
2001 ◽  
Vol 44 (5) ◽  
pp. 752-762 ◽  
Author(s):  
Angeliki Gariou-Papalexiou ◽  
Anastassios C Mintzas ◽  
Antigone Zacharopoulou
Keyword(s):  
Protein Synthesis ◽  
Salivary Glands ◽  
Ceratitis Capitata ◽  
Polytene Chromosomes ◽  
Fruit Fly ◽  
Protein Synthesis Inhibitor ◽  
Synthesis Inhibitor ◽  
Stage 1

The effect of ecdysone on the puffing activity of the polytene chromosomes of Ceratitis capitata has been studied in organ cultures of late-larval salivary glands. Culture of glands from 120-h-old larvae (puff stage 1) in the presence of ecdysone resulted in the initiation of the late-larval puffing cycle that is normally observed in 145-h-old larvae (puff stage 4). During a 7-h period in the presence of ecdysone, the puffing patterns of most loci resembled the in vivo patterns observed in the period between puff stages 4 and 10, indicating that the first puffing cycle can be initiated by the hormone and proceed almost to completion, in vitro. Culture of salivary glands in the presence of ecdysone and a protein-synthesis inhibitor, as well as ecdysone withdrawal and readdition experiments, indicated that most of the ecdysone-regulated puffs could be categorized into three classes: (i) the puffs that were suppressed immediately by ecdysone, even in the absence of protein synthesis; (ii) the puffs that were induced directly by ecdysone; and (iii) the puffs that were induced indirectly by ecdysone, that is, they were induced after a lag period of a few hours and required protein synthesis for their induction.Key words: polytene chromosomes, puffing patterns, ecdysone, Ceratitis capitata.

Thrombopoietin-Induced Stimulation of Megakaryocyte- Enriched Bone Marrow Cultures

1979 ◽  
Author(s):  
K. L. Kellar ◽  
B. L. Evatt ◽  
C. R. McGrath ◽  
R. B. Ramsey
Keyword(s):  
Bone Marrow ◽  
Dna Synthesis ◽  
Bone Marrow Cells ◽  
Rabbit Plasma ◽  
Bone Marrow Cultures ◽  
Plasma Fractions ◽  
Marrow Cultures ◽  
Stimulation Of

Liquid cultures of bone marrow cells enriched for megakaryocytes were assayed for incorporation of 3H-thymidine (3H-TdR) into acid-precipitable cell digests to determine the effect of thrombopoietin on DNA synthesis. As previously described, thrombopoietin was prepared by ammonium sulfate fractionation of pooled plasma obtained from thrombocytopenic rabbits. A control fraction was prepared from normal rabbit plasma. The thrombopoietic activity of these fractions was determined in vivo with normal rabbits as assay animals and the rate of incorporation of 75Se-selenomethionine into newly formed platelets as an index of thrombopoietic activity of the infused material. Guinea pig megakaryocytes were purified using bovine serum albumin gradients. Bone marrow cultures containing 1.5-3.0x104 cells and 31%-71% megakaryocytes were incubated 18 h in modified Dulbecco’s MEM containing 10% of the concentrated plasma fractions from either thrombocytopenic or normal rabbits. In other control cultures, 0.9% NaCl was substituted for the plasma fractions. 3H-TdR incorporation was measured after cells were incubated for 3 h with 1 μCi/ml. The protein fraction containing thrombopoietin-stimulating activity caused a 25%-31% increase in 3H-TdR incorporation over that in cultures which were incubated with the similar fraction from normal plasma and a 29% increase over the activity in control cultures to which 0.9% NaCl had been added. These data suggest that thrombopoietin stimulates DNA synthesis in megakaryocytes and that this tecnique may be useful in assaying thrombopoietin in vitro.

scholarly journals Contamination of erythropoietin by endotoxin: in vivo and in vitro effects on murine erythropoiesis

Blood ◽  
1979 ◽  
Vol 54 (1) ◽  
pp. 146-158 ◽  
Author(s):  
KS Zuckerman ◽  
PJ Quesenberry ◽  
J Levin ◽  
R Sullivan
Keyword(s):  
Significant Inhibition ◽  
Erythropoietic Activity ◽  
Limulus Amebocyte Lysate ◽  
Endogenous Erythropoietin ◽  
Significant Change ◽  
In Vitro Effects ◽  
Stimulation Of

Abstract Endotoxin was detected in all erythropoietin preparations tested and was removed from four lots, without loss of erythropoietic activity, by adsorption with limulus amebocyte lysate. Comparison of adsorbed (endotoxin-depleted) and nonadsorbed (endotoxin-containing) erythropoietin preparations demonstrated significant inhibition of CFU- e and BFU-e in vitro by nonadsorbed erythropoietin at concentrations higher than 0.25 U/ml and 2.0 U/ml, respectively. CFU-e and BFU-e were inhibited significantly by readdition in vitro of 10(-5)-10(-3) mug of endotoxin per unit of limulus-adsorbed erythropoietin. Administration of saline or 6 U of nonadsorbed or adsorbed erythropoietin twice a day for 4 days of CF1 mice resulted in reticulocyte counts of 2.1%, 9.9%, and 15.9%, respectively. Nonadsorbed erythropoietin resulted in a 29% decrease in erythropoiesis, a 42% decrease in CFU-e, and a 16% increase in granulopoiesis in the marrow, whereas adsorbed erythropoietin caused a 28% increase in erythropoiesis, no significant change in CFU-e and a 19% decrease in granulopoiesis in the marrow. Both preparations resulted in marked increases in splenic erythropoiesis and granulopoiesis. The effects of adsorbed erythropoietin are similar to those produced following stimulation of hematopoiesis by endogenous erythropoietin. Hemopoietic changes induced by nonadsorbed erythropoietin in vivo and in vitro are affected substantially by contamination of the erythropoietin preparations with endotoxin.

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