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  • 1
    Electronic Resource
    Electronic Resource
    Synthesis and secretion of mucoprotein glue in the salivary gland ofDrosophila melanogaster (1975)
    Springer
    Development genes and evolution 178 (1975), S. 15-28 
    Details
    ISSN: 1432-041X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The processes of involved in the accumulation and secretion of adhesive mucoprotein (“glue”) in third instar larvae ofD. melanogaster are described. The RNA templates for glue protein seem to be synthesized within 72–85 hours after oviposition, because treatment of larvae at this age with actinomycin D inhibits the accumulation of the secretion. The secretory granules appear in the salivary gland cells of 90 hour larvae and are discharged into the gland lumen of 118 hour larvae. Secretion of mucoprotein material by salivary gland cells into the gland lumen depends on high ecdysone concentration. Mucoproteins are synthesized, but not discharged, by these cells in ecdysone-deficient homozygousl (2) gl larvae as well as in normal larvae isolated from ecdysone by ligatures or transplantation of the salivary glands into adult abdomens. Ecdysterone injection into normal 100 hour larvae, 7 dayl (2) gl larvae or into adult imaginal abdomens into which salivary glands have previously been stimulates mucoprotein secretion into the gland lumen. Determination of total protein content in the salivary gland by Lowry's method has shown that “glue” proteins make up 21–32% of the total protein content in the gland. The glands of thel (3) tl mutant do not give a PAS-positive reaction, nor are the granules of the secretion observed under the phase contrast microscope.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00848359
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  • 2
    Electronic Resource
    Electronic Resource
    Comparative study of the function of polytene chromosomes in laboratory stocks ofDrosophila melanogaster and thel (3)tl mutant (lethal tumorous larvae) (1976)
    Springer
    Chromosoma 55 (1976), S. 121-136 
    Details
    ISSN: 1432-0886
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract The salivary chromosomes of thel (3)tl mutant of D. melanogaster are considerably thicker and shorter than those of normal larvae. In most nuclei, chromosome shortening is associated with morphological changes of two types, a) The bands lose their distinctive pattern and become loose. The chromosome appears as a granular mass. In extreme cases pompon-like chromosomes arise. Most frequently male X-chromosomes undergo such changes and begin to shorten as early as in the middle of third larval instar. “Pompon” transformation is not associated with a change in the relative intensity of RNA synthesis: the ratio of silver grain number over the male X-chromosome to that over regions 61A-63F is the same in pompon-likel (3)tl chromosomes and in the male and female X-chromosomes of the normal lines, b) Shortened chromosomes occassionally retain distinct band organization and, in these cases, chromosome shortening is observed to be due to the condensation of the chromatin of many puffs and interbands resulting in the fusion of a large number of bands into “new” chromatin blocks. In regions of fused bands, transcriptional activity is decreased as compared with regions where this union does not occur. The chromosomes ofl (3)tl larvae lack ecdysonestimulated puffs and other prominent puffs. In 144–192 hour larvae, puffs can be induced by ecdysone and until 384 hours by temperature shock. The capacity of puff induction decreases with larval age.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01798344
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  • 3
    Electronic Resource
    Electronic Resource
    Electron microscope autoradiographic study on transcriptional activity of Drosophila melanogaster polytene chromosomes (1979)
    Springer
    Chromosoma 73 (1979), S. 163-177 
    Details
    ISSN: 1432-0886
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract Incorporation of 3H-uridine into three chromosome regions 21D, 100AB, 7EF showing no puffs was studied by means of EM autoradiography. These regions show rather good coincidence between EM and Bridges' revised maps. The reduction of band number observed in the EM map was mainly at the expense of “doublet” bands. — Theoretical silver grain distributions were calculated on the basis of “universal curves” (Salpeter et al., 1969, J. Cell Biol. v. 41, 1–20) on condition that either bands or interbands are linear sources of radioactivity. From these curves the resolution of EM autoradiography was deduced to be sufficient with regard to the investigated region. — The results show that in addition to the puffs peaks of silver grains occur over the interbands and diffuse bands. The lowest incorporation level is observed over the dense bands. The possibility of utilizing the data obtained for the location of RNA-synthesising regions is discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00331569
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  • 4
    Electronic Resource
    Electronic Resource
    Fine cytogenetical analysis of the band 10a1-2 and the adjoining regions in the Drosophila melanogaster X chromosome (1981)
    Springer
    Chromosoma 82 (1981), S. 9-23 
    Details
    ISSN: 1432-0886
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract The region 9E1-2 — 10B1-2 of the Drosophila melanogaster X chromosome was analysed under the light (LM) and the electron (EM) microscope using different fixatives and an EM map of the region was constructed. EM analysis revealed 21 bands in the region 9E1-2 — 10B1-2 instead of 36 bands in Bridges' map. This descrepancy mainly results from the fact that 14 bands indicated as “doublets” by Bridges appear as a single bands. No doublets were found in the whole 9B1-2 — 10C1-2 region after fixation of salivary glands in 3% glutaraldehyde, 3% formaldehyde and 3∶1 ethanol-acetic acid mixture. 45% acetic acid is the only fixative which results in strongly vacuolated appearance of the bands. — The break points of 30 chromosome rearrangements in the region 9E1-2 — 10B1-2 were located under EM or LM within the limits of the EM map of this region.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00285746
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  • 5
    Electronic Resource
    Electronic Resource
    Cytogenetic analysis of the X-chromosome region 2B1-2-2B9-10 of Drosophila melanogaster (1985)
    Springer
    Chromosoma 92 (1985), S. 351-356 
    Details
    ISSN: 1432-0886
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract In salivary glands of yellow control stock the puffing pattern in the ecdysone-added artificial C46P medium was on the whole similar to that observed during larval development in vivo. However, underdevelopment of a series of late puffs and a delay in the regression of early puffs were observed. In addition a set of “medium” puffs not visible in vivo appeared. Late puffs differed from those developing in Grace medium. When salivary glands of homozygotes for the lethal dor lt187, a mutation that causes death in the third instar with no signs of ecdysone induction were incubated with ecdysterone, the development of puffs was restored, i.e., the puffing pattern of mutant cells in vitro practically did not differ from that in cells of the control stock. This implies that the dor lt187 lethal allele belongs to the class of ecdysone-deficient mutations.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00327466
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  • 6
    Electronic Resource
    Electronic Resource
    Electron microscopical analysis of Drosophila polytene chromosomes (1985)
    Springer
    Chromosoma 91 (1985), S. 210-233 
    Details
    ISSN: 1432-0886
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract Data are presented of electron microscopic (EM) analysis of consecutive developmental stages of Drosophila melanogaster complex puffs, formed as a result of simultaneous decondensation of several bands. EM mapping principles proposed by us permitted more exact determination of the banding patterns of 19 regions in which 31 puffs develop. It is shown that 20 of them develop as a result of synchronous decondensation of two bands, 7 of three and 4 of one band. Three cases of two-band puff formation when one or both bands undergo partial decondensation are descirbed. In the 50CF, 62CE, 63F and 71CF regions puffing zones are located closely adjacent to each other but the decondensation of separate band groups occurs at different puff stages (PS). These data are interpreted as activation of independently regulated DNA sequences. The decondensation of two or three adjacent bands during formation of the majority of the puffs occurs simultaneously in the very first stages of their development. It demonstrates synchronous activation of the material of several bands presumably affected by a common inductor. Bands adjacent to puffing centres also lose their clarity as the puff develops, probably due to “passive” decondensation connected with puff growth. The morphological data obtained suggest a complex genetic organisation of many puffs.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00328218
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  • 7
    Electronic Resource
    Electronic Resource
    Cytogenetic analysis of region 2B3-4-2B11 of the X-chromosome of Drosophila melanogaster (1987)
    Springer
    Chromosoma 95 (1987), S. 295-310 
    Details
    ISSN: 1432-0886
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract About 160 kb of DNA were cloned from the 2B region of the X chromosome, where the early ecdysone puff develops and the ecs locus is located. On the physical map of this sequence the positions of 13 chromosome rearrangement breakpoints interfering with both puff development and the ecs locus proximally and distally, were plotted by means of in situ hybridization. The maximal size of the ecs locus is about 100 kb (between the breakpoint of In(1)Hw 49c and the proximal end of Df(1)St472) The DNA sequences essential for normal puffing are located within the ecs locus between the In(1)br lt103 and Df(1)St472 breakpoints and comprise about 65 kb. Thus the puff develops as a result of ecs activation. Since Df(1)P154, which reduces the puff size and removes the proximal part of the ecs locus, does not prevent puff induction by ecdysone, while removing the distal part of the locus by Df(1)St469 completely stops development of the puff, we conclude that the regulatory zone of the locus, which reacts to hormone is located in the distal parts of both the puff and the locus, proximal to the breakpoint of In(1)br lt103 .Since In(1)br lt103 , Df(1)pn7b and Df(1)br R1 damage ecs but do not prevent puffing it is proposed that there is a second regulatory zone for this locus with a minimal size of 15–20 kb (between the breakpoints of Df(1)br R1 and In(1)br lt103). After cytogenetic and electron microscopic analysis of 2B puff formation it seems very likely that the site of puff formation is situated in the proximal part of 2B3-4 and after enhancement of ecs expression by hormone it spreads proximally to the 2B6 band which does not puff. When the puff regresses at puff stages (PS)10-11 its material does not condense completely and a zone of residual puffing joins the condensed material located distal to it. This material can give the impression of a separate band, designated 2B5 in Bridges' map. For convenience we propose to call the site giving rise to the puff as 2B3-5.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00294787
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  • 8
    Electronic Resource
    Electronic Resource
    Cytogenetic and molecular aspects of position effect variegation in Drosophila melanogaster (1988)
    Springer
    Chromosoma 96 (1988), S. 255-261 
    Details
    ISSN: 1432-0886
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract The peculiarities of compact blocks appearing as a consequence of position effect variegation were studied in male polytene chromosomes. In T(1;2)dor var7 /Y males the frequency of nuclei with a block in the 2B region was lower at all temperature and the chromosome regioninvolved in compaction was shorter than in T(1;2)dor var7 /FM6 females. The fraction of nuclei with blocks was considerably increased indor var7 /0 males, especially at 18° C when the viability of these males is sharply reduced. The following features distinguish theblocks in males from those in females: (i) compaction of the 2B region in the males results in genetic inactivation only to a very small extent; (ii) the structure of the blocks in males is diffuse; and(iii) the male blocks still maintain some transcriptional activity as indicated by 3H-uridine incorporation. The temperaturesensitive period of both block formation and geneticinactivation was found to be during the first 3 h of embryonic development.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00302365
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  • 9
    Electronic Resource
    Electronic Resource
    3H-Uridine labelling patterns in the Drosophila melanogaster salivary gland chromosomes X, 2R and 3L (1975)
    Springer
    Chromosoma 49 (1975), S. 219-231 
    Details
    ISSN: 1432-0886
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract RNA-synthesizing regions in the polytene chromosomes of D. melanogaster were located; the level of 3H-uridine incorporation in each of these regions was determined. — It was found that the number of RNA-synthesizing regions is much larger than the number of puffs: almost all the chromosome regions are labelled except dense bands. In most cases, “non-puffed” regions label 10 to even 100 times weaker than prominent puffs. Typical puffs, i.e. loci with increased chromosome diameter, together contain about 50% 3H-uridine incorporated into the chromosomes. — In general, there is a correlation between puff size and RNA synthetic activity, so that 3H-uridine incorporation rate increases directly with puff volume. However, within each class individual puffs differ in labelling intensity by many times. It is suggested that many regions of “small puffs”, including interbands, represent chromosome loci with constant transcriptional activity.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00361067
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  • 10
    Electronic Resource
    Electronic Resource
    Cytogenetic analysis of the 2B3-4-2B11 Region of the X-chromosome of Drosophila melanogaster (1980)
    Springer
    Chromosoma 81 (1980), S. 281-306 
    Details
    ISSN: 1432-0886
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract There are, at least, 11 distinct single bands and one real doublet in the region 2B1-2-2C1-2 of the X-chromosome of Drosophila melanogaster. This figure coincides with that in Bridges' revised map with most of the “doublet” bands being artifacts. Three puffs appear in the region. The early ecdysone-specific puff 2B5-6, small at PS(puffing stage) 1, increases sharply at PS 2. The late ecdysone-specific puff 2C1-2 appears at PS 4–5. At PS 9–10, when 2B5-6 disappears completely and 2C1-2 decreases, a third puff at 2B11 appears. None of these puffs is active at PS 11. Morphological analysis of puff appearance and autoradiographic study of 3H-uridine incorporation into chromosomes carrying rearrangements within the 2B region suggest that the early ecdysone-specific puff derives from bands 2B5 and may be 2B6, while the neighbouring bands 2B1-4, and 2B7-10 do not show appreciable transcription at the investigated stages. There are 42 mutations affecting viability in the region where the 2B5-6 puff is located. The mutations belong to 6 complementation groups; two of the groups dor and swi, are independent while the rest are overlapped by several lethal mutations (overlapping complex.) Mutants of the different groups have series of similar characteristics: temperature sensitivity, dose sensitivity, larva-pupal lethality and similar morphological abnormalities. It can be assumed that there is a functionally linked cluster of genes within the region 2B. Complementation groups br, rbp, l(1)pp-, l(1)pp-2 (overlapping complex) have been located by rearrangements in very narrow cytological limit 2B3-4-2B5 that is in the area of developing puff. Two other loci dor and swi are situated some to the right of 2B5.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00285954
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