scholarly journals Stable torsional tension in DNA of Chironomus thummi polytene chromosomes

1999 ◽  
Vol 15 (6) ◽  
pp. 510-515 ◽  
Author(s):  
F. Kuzin ◽  
Keyword(s):  
Polytene Chromosomes ◽  
Chironomus Thummi

scholarly journals Superhelical DNA of polytene chromosomes Chironomus thummi

1988 ◽  
Vol 4 (3) ◽  
pp. 129-133
Author(s):  
M. A. Shurdov ◽  
A. D. Gruzdev
Keyword(s):  
Polytene Chromosomes ◽  
Chironomus Thummi

DNA and RNA content of Chironomus thummi polytene chromosomes determined by micro column gel filtration

1975 ◽  
Vol 3 (6) ◽  
pp. 361-370 ◽  
Author(s):  
Edgard Serfling ◽  
Vladimir I. Majorov ◽  
Nikolai I. Mikichur ◽  
Taissya G. Popova ◽  
Lev S. Sandakchiev
Keyword(s):  
Polytene Chromosomes ◽  
Gel Filtration ◽  
Dna And Rna ◽  
Rna Content ◽  
Chironomus Thummi

Identification of left-handed Z-DNA by indirect immunofluorescence in polytene chromosomes of Chironomus thummi thummi

1982 ◽  
Vol 141 (2) ◽  
pp. 508-513 ◽  
Author(s):  
F. Lemeunier ◽  
C. Derbin ◽  
B. Malfoy ◽  
M. Leng ◽  
E. Taillandier
Keyword(s):  
Indirect Immunofluorescence ◽  
Polytene Chromosomes ◽  
Left Handed ◽  
Z Dna ◽  
Chironomus Thummi

scholarly journals Inherited and somatic cytogenetic variability in Palearctic populations of Chironomus riparius Meigen 1804 (Diptera, Chironomidae)

Genome ◽  
2004 ◽  
Vol 47 (2) ◽  
pp. 332-344 ◽  
Author(s):  
Gabriella Sella ◽  
Stefano Bovero ◽  
Marco Ginepro ◽  
Paraskeva Michailova ◽  
Ninel Petrova ◽  
...  
Keyword(s):  
Heavy Metal ◽  
Metal Pollution ◽  
Heavy Metal Pollution ◽  
Polytene Chromosomes ◽  
Chironomus Riparius ◽  
Heterozygous State ◽  
Chironomid Species ◽  
Different Types ◽  
Chironomus Thummi ◽  
Somatic Aberrations

Inter- and intracytogenetic variability was analyzed in 13 natural Palearctic populations of Chironomus riparius Meigen 1804 (syn. Chironomus thummi) by examining hereditary and somatic aberrations (mainly inversions) of the salivary gland polytene chromosomes. In total, 77 different types of inherited inversion sequences and 184 different types of somatic inversions were found. The median percent frequency of inherited inversions was 1.4% and karyotypic divergence between populations was very low. Most hereditary inversions were endemic and always in a heterozygous state. Only six inversion sequences, each of them shared by two very distant populations, may be considered a relic of very ancient ancestral inversions. Unlike inherited inversions, occurrence of somatic aberrations seems to increase with the overall rise in the level of heavy metal pollution of the sediments from which larvae were sampled. In contrast with what occurs in populations of other chironomid species, populations of C. riparius do not seem to undergo a process of cytogenetic differentiation.Key words: Chironomus thummi, polytene chromosomes, inversion polymorphism, somatic aberrations, heavy metal pollution.

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.

scholarly journals Histone localization in polytene chromosomes by immunofluorescence.

1978 ◽  
Vol 78 (3) ◽  
pp. 910-918 ◽  
Author(s):  
P D Kurth ◽  
E N Moudrianakis ◽  
M Bustin
Keyword(s):  
Acetic Acid ◽  
Indirect Immunofluorescence ◽  
Polytene Chromosomes ◽  
Immunofluorescence Technique ◽  
Banding Patterns ◽  
Calf Thymus ◽  
Indirect Immunofluorescence Technique ◽  
Dense Band ◽  
Chironomus Thummi

Polytene chromosomes of Chironomus thummi were treated with antisera elicited by purified calf thymus histone fractions, and the location of each histone type was visualized by the indirect immunofluorescence technique. Each of the antisera produced specific and distinct patterns of fluorescence, suggesting that it is possible to use the indirect immunofluorescence technique to study the in situ organization of each histone in the various regions of the chromosomes. H1 and H2A antisera produced diffuse fluorescence patterns in acetic acid-fixed chromosomes which become more defined in formaldehyde-fixed preparations. Antisera to H2B, H3 and H4, when reacted with either formaldehyde- or acetic acid-fixed chromosomes, produce distinct banding patterns closely resembling the banding of acetoorcein-stained or phase-contrast-differentiated chromosomal preparations. These antisera produce corresponding patterns of fluorescence for each chromosome, suggesting that the overall organization of the histones is similar in the various bands. Because the dense band regions stain more brightly with antihistone sera than the less compacted interband areas, we believe that the number of antigenic sites of chromosome-bound histones is related to the amount of DNA present, and that the accessibility of histone determinants does not differ between the bands and interbands.

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.

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