Wilhelm Roux' Archiv f�r Entwicklungsmechanik der Organismen, 1973
Alkaline phosphatases and several dehydrogenases and oxidases separated by a microdisc electropho... more Alkaline phosphatases and several dehydrogenases and oxidases separated by a microdisc electrophoresis technique have been studied during larval and early pupal development ofD. pseudoobscura salivary glands, fat body, hemolymph, body wall and whole body. Tissue-specific enzymes were observed and the qualitative differences occurring during the development are discussed.
Members of a group of Australian Chironomus species in the pseudothummi complex show wide variati... more Members of a group of Australian Chironomus species in the pseudothummi complex show wide variation in number and location of nucleolar organizing regions (NORs). The structure of these regions has been examined by phase contrast microscopy and silver banding of salivary gland polytene chromosomes. Presence of nucleoli was also checked on other types of chromosomes in some species. The contribution of the silver banding technique to nucleolar studies in these chironomid chromosomes is discussed. Nucleoli often seem to emerge from groups of (up to 9) bands. Further studies are necessary to confirm the presence of rRNA cistrons in all of these bands. Banding differences, in particular absence of bands from homologous regions of some species which have smaller nucleoli or lack particular nucleoli, have been found. In the case of Ch. tepperi, however, little banding difference is apparent in the 16B region between the N(IV)+ and N(IV)- chromosomes, although in situ hybridization (Eigenbrod 1978) shows a deletion of rRNA cistrons in the N(IV)- stock. Differences in heterochromatin amount have also been observed at different NORs. A scheme for the evolution of nucleolar-producing regions in this Chironomus group in terms of these and other known chromosomal changes is presented and discussed.
Brazilian journal of medical and biological research = Revista brasileira de pesquisas médicas e biológicas / Sociedade Brasileira de Biofísica ... [et al.], 1984
The poly(A)+RNAs produced during DNA puff formation in the salivary gland of R. americana were us... more The poly(A)+RNAs produced during DNA puff formation in the salivary gland of R. americana were used to detect the DNA sequences involved in their transcription, using the Southern hybridization and in situ hybridization techniques. DNA prepared from salivary gland after DNA puff regression and carcass were cleaved with EcoRI and hybridized to poly(A)+RNA. After hybridization two major bands corresponding to sizes of 3.0 and 6.0 kb were detected. The hybridization level in the salivary gland DNA was approximately 5-fold that observed with carcass DNA. After in situ hybridization, approximately 10 chromosome regions were labelled. The most highly labelled chromosome regions were C3d and C8e. These regions have been described as DNA puffs that undergo amplification at a specific stage of larval development.
Members of a group of Australian Chironomus species in the pseudothummi complex show wide variati... more Members of a group of Australian Chironomus species in the pseudothummi complex show wide variation in number and location of nucleolar organizing regions (NORs). The structure of these regions has been examined by phase contrast microscopy and silver banding of salivary gland polytene chromosomes. Presence of nucleoli was also checked on other types of chromosomes in some species. The contribution of the silver banding technique to nucleolar studies in these chironomid chromosomes is discussed. Nucleoli often seem to emerge from groups of (up to 9) bands. Further studies are necessary to confirm the presence of rRNA cistrons in all of these bands. Banding differences, in particular absence of bands from homologous regions of some species which have smaller nucleoli or lack particular nucleoli, have been found. In the case of Ch. tepperi, however, little banding difference is apparent in the 16B region between the N(IV)+ and N(IV)- chromosomes, although in situ hybridization (Eigenbrod 1978) shows a deletion of rRNA cistrons in the N(IV)- stock. Differences in heterochromatin amount have also been observed at different NORs. A scheme for the evolution of nucleolar-producing regions in this Chironomus group in terms of these and other known chromosomal changes is presented and discussed.
Wilhelm Roux' Archiv f�r Entwicklungsmechanik der Organismen, 1973
Alkaline phosphatases and several dehydrogenases and oxidases separated by a microdisc electropho... more Alkaline phosphatases and several dehydrogenases and oxidases separated by a microdisc electrophoresis technique have been studied during larval and early pupal development ofD. pseudoobscura salivary glands, fat body, hemolymph, body wall and whole body. Tissue-specific enzymes were observed and the qualitative differences occurring during the development are discussed.
Members of a group of Australian Chironomus species in the pseudothummi complex show wide variati... more Members of a group of Australian Chironomus species in the pseudothummi complex show wide variation in number and location of nucleolar organizing regions (NORs). The structure of these regions has been examined by phase contrast microscopy and silver banding of salivary gland polytene chromosomes. Presence of nucleoli was also checked on other types of chromosomes in some species. The contribution of the silver banding technique to nucleolar studies in these chironomid chromosomes is discussed. Nucleoli often seem to emerge from groups of (up to 9) bands. Further studies are necessary to confirm the presence of rRNA cistrons in all of these bands. Banding differences, in particular absence of bands from homologous regions of some species which have smaller nucleoli or lack particular nucleoli, have been found. In the case of Ch. tepperi, however, little banding difference is apparent in the 16B region between the N(IV)+ and N(IV)- chromosomes, although in situ hybridization (Eigenbrod 1978) shows a deletion of rRNA cistrons in the N(IV)- stock. Differences in heterochromatin amount have also been observed at different NORs. A scheme for the evolution of nucleolar-producing regions in this Chironomus group in terms of these and other known chromosomal changes is presented and discussed.
Brazilian journal of medical and biological research = Revista brasileira de pesquisas médicas e biológicas / Sociedade Brasileira de Biofísica ... [et al.], 1984
The poly(A)+RNAs produced during DNA puff formation in the salivary gland of R. americana were us... more The poly(A)+RNAs produced during DNA puff formation in the salivary gland of R. americana were used to detect the DNA sequences involved in their transcription, using the Southern hybridization and in situ hybridization techniques. DNA prepared from salivary gland after DNA puff regression and carcass were cleaved with EcoRI and hybridized to poly(A)+RNA. After hybridization two major bands corresponding to sizes of 3.0 and 6.0 kb were detected. The hybridization level in the salivary gland DNA was approximately 5-fold that observed with carcass DNA. After in situ hybridization, approximately 10 chromosome regions were labelled. The most highly labelled chromosome regions were C3d and C8e. These regions have been described as DNA puffs that undergo amplification at a specific stage of larval development.
Members of a group of Australian Chironomus species in the pseudothummi complex show wide variati... more Members of a group of Australian Chironomus species in the pseudothummi complex show wide variation in number and location of nucleolar organizing regions (NORs). The structure of these regions has been examined by phase contrast microscopy and silver banding of salivary gland polytene chromosomes. Presence of nucleoli was also checked on other types of chromosomes in some species. The contribution of the silver banding technique to nucleolar studies in these chironomid chromosomes is discussed. Nucleoli often seem to emerge from groups of (up to 9) bands. Further studies are necessary to confirm the presence of rRNA cistrons in all of these bands. Banding differences, in particular absence of bands from homologous regions of some species which have smaller nucleoli or lack particular nucleoli, have been found. In the case of Ch. tepperi, however, little banding difference is apparent in the 16B region between the N(IV)+ and N(IV)- chromosomes, although in situ hybridization (Eigenbrod 1978) shows a deletion of rRNA cistrons in the N(IV)- stock. Differences in heterochromatin amount have also been observed at different NORs. A scheme for the evolution of nucleolar-producing regions in this Chironomus group in terms of these and other known chromosomal changes is presented and discussed.
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