Abstract:
:The mean DNA content of G2 macronuclei varies during the life cycle of the ciliate Tetrahymena thermophila. Early in the life cycle the mean is about 130 C; later it is about 94 C. In hybrids between strains A and B the decrease from 130 C to 94 C usually began after 60 fissions after conjugation. In B X B clones the decrease was complete by 50 fissions. The data suggest that there may be a genetic difference between strains A and B with respect to the onset of the decrease in DNA content. The downward regulation of the mean DNA content appears to be related to the mechanism which removes the variance in macronuclear DNA content which is added to macronuclei by unequal macronuclear division. Unequal macronuclear division regularly occurs at all stages of the life cycle, with larger macronuclei tending to divide more unequally. In the absence of regulation, unequal macronuclear division would constantly add variance to G1 macronuclei and their range would continue to increase. Analysis of the variances of G1 and G2 macronuclei suggests that at all stages of the life cycle the added variance is removed by acting upon nuclei which become too small or too large. According to this model, macronuclei with smaller amounts of DNA are regulated upward by an extra macronuclear S phase, while larger amounts are regulated downward by chromatin extrusion and the skipping of macronuclear S. The mean DNA content appears to change during the life cycle because the thresholds at which macronuclei become too small or too large are readjusted. It is postulated that these thresholds are a function of gene dosage.
journal_name
Chromosomajournal_title
Chromosomaauthors
Doerder FP,DeBault LEdoi
10.1007/BF00327377subject
Has Abstractpub_date
1978-10-20 00:00:00pages
1-19issue
1eissn
0009-5915issn
1432-0886journal_volume
69pub_type
杂志文章相关文献
CHROMOSOMA文献大全abstract::The MRE11/RAD50/NBS1 complex (Mre11 complex) is a central player in most aspects of the cellular response to DNA double-strand breaks, including homologous recombination, non-homologous end joining, telomere maintenance and DNA damage checkpoint activation. Several of these findings are explained by the unusual enzyma...
journal_title:Chromosoma
pub_type: 杂志文章,评审
doi:10.1007/s00412-004-0306-4
更新日期:2004-10-01 00:00:00
abstract::Using fluorescence in situ hybridization, conventional epifluorescence microscopy, and laser scanning confocal microscopy followed by three-dimensional reconstruction we describe a well-defined higher order packaging of the human genome in the sperm cell nucleus. This was determined by the spatial localization of cent...
journal_title:Chromosoma
pub_type: 杂志文章
doi:10.1007/BF00357684
更新日期:1995-05-01 00:00:00
abstract::Changes in the nuclear positioning of specific genes, depending on their expression status, have been observed in a large diversity of physiological processes. However, gene position is poorly documented for immune cells which have been subjected to activation following bacterial infection. Using a pig model, we focus...
journal_title:Chromosoma
pub_type: 杂志文章
doi:10.1007/s00412-011-0328-7
更新日期:2011-10-01 00:00:00
abstract::Normal lepidopteran males produce two kinds of spermatozoa: nucleate (eupyrene) and anucleate (apyrene). Eupyrene spermatozoa have the usual type of elongate nuclei. But in apyrene spermatids, the nuclei never elongate and the chromatin remains in a telophase-like condition until enucleation occurs. The study of the d...
journal_title:Chromosoma
pub_type: 杂志文章
doi:10.1007/BF00330361
更新日期:1982-01-01 00:00:00
abstract::Very few of the middle repetitive DNA sequences found in Drosophila melanogaster are present in all of the species of the D. melanogaster subgroup. One member of the subgroup, D. erecta, lacks most of the families of repetitive elements from D. melanogaster (including copia and 412) but possesses many other families n...
journal_title:Chromosoma
pub_type: 杂志文章
doi:10.1007/BF00327329
更新日期:1983-01-01 00:00:00
abstract::Metaphase chromosomes prepared from colcemid-treated mouse L929 cells by non-ionic detergent lysis exhibit distinct heterochromatic centromere regions and associated kinetochores when viewed by whole mount electron microscopy. Deoxyribonuclease I treatment of these chromosomes results in the preferential digestion of ...
journal_title:Chromosoma
pub_type: 杂志文章
doi:10.1007/BF00330554
更新日期:1978-04-25 00:00:00
abstract::Replication times for all important chromosome bands, of both types R and Q (277 structures) are analysed. The R-bands form a group of structures whose DNA replicates during the early S-phase, while the DNA situated in the Q-bands replicates during the late S-phase. There may not exist overlapping between replication ...
journal_title:Chromosoma
pub_type: 杂志文章
doi:10.1007/BF00293440
更新日期:1976-10-12 00:00:00
abstract::The nature of replication origins in eukaryotic chromosomes has been examined in some detail only in yeast, Drosophila, and mammalian cells. We have used highly synchronous cultures of plasmodia of the myxomycete Physarum and two-dimensional agarose gel electrophoresis to examine replication of two developmentally con...
journal_title:Chromosoma
pub_type: 杂志文章
doi:10.1007/BF00368349
更新日期:1993-09-01 00:00:00
abstract::Insulator proteins orchestrate the three-dimensional organization of the genome. Insulators function by facilitating communications between regulatory sequences and gene promoters, allowing accurate gene transcription regulation during embryo development and cell differentiation. However, the role of insulator protein...
journal_title:Chromosoma
pub_type: 杂志文章
doi:10.1007/s00412-020-00743-8
更新日期:2020-12-01 00:00:00
abstract::Among his many contributions to the field of chromosome structure and dynamics, J. Herbert Taylor showed that eukaryotic cells have many more potential replication origins than they use, which they can recruit when replication forks are slowed to complete S-phase in a timely fashion. Thirty years later, his findings r...
journal_title:Chromosoma
pub_type: 杂志文章,评审
doi:10.1007/s00412-007-0105-9
更新日期:2007-08-01 00:00:00
abstract::Allopolyploidy and homoeologous recombination are two important processes in reshaping genomes and generating evolutionary novelties. Newly formed allopolyploids usually display chromosomal perturbations as a result of pairing errors at meiosis. To understand mechanisms of stabilization of allopolyploid species derive...
journal_title:Chromosoma
pub_type: 杂志文章
doi:10.1007/s00412-017-0635-8
更新日期:2017-12-01 00:00:00
abstract::In the domestic pig (2n = 38) two types of constitutive heterochromatin can be differentiated by fluorescence counterstaining techniques. All 24 biarmed autosomes and the X chromosome have chromomycin A3-positive centromeric C-bands, whereas all 12 acrocentric chromosomes exhibit DA-DAPI-positive centromeric heterochr...
journal_title:Chromosoma
pub_type: 杂志文章
doi:10.1007/BF00286480
更新日期:1984-01-01 00:00:00
abstract::X chromosome inactivation (XCI) is an essential mechanism to compensate gene dosage in mammals. Here, we show that XCI has evolved differently in two species of the genus Tokudaia. The Amami spiny rat, Tokudaia osimensis, has a single X chromosome in males and females (XO/XO). By contrast, the Okinawa spiny rat, Tokud...
journal_title:Chromosoma
pub_type: 杂志文章
doi:10.1007/s00412-017-0639-4
更新日期:2017-12-01 00:00:00
abstract::Heterochromatin in eukaryotic interphase cells frequently localizes to the nucleolar periphery (nucleolus-associated domains (NADs)) and the nuclear lamina (lamina-associated domains (LADs)). Gene expression in somatic cell NADs is generally low, but NADs have not been characterized in mammalian stem cells. Here, we g...
journal_title:Chromosoma
pub_type: 杂志文章
doi:10.1007/s00412-020-00734-9
更新日期:2020-06-01 00:00:00
abstract::Experiments were designed to test whether nonrandom segregation of sister chromatids at mitosis has a role in the production of cell diversity during embryogenesis, Segregation was examined in vivo in retinal cells from embryonic chicks. Chromatids were labelled with bromouracil and stained by the fluorescence plus Gi...
journal_title:Chromosoma
pub_type: 杂志文章
doi:10.1007/BF00288461
更新日期:1977-03-16 00:00:00
abstract::We studied the stability of the genomic distribution of six retrotransposon families in long-term and short-term cultures of Drosophila cells. In a subclone derived from Kc cells, no significant rearrangements were detected over an 8 year period. On the contrary, extensive reshuffling and amplification of transposon f...
journal_title:Chromosoma
pub_type: 杂志文章
doi:10.1007/BF00292963
更新日期:1988-11-01 00:00:00
abstract::Human lymphocytes were grown for one replication cycle in BrdU, stained with 33258 Hoechst, exposed to UV light and subsequently treated with 2 x SSC and stained with Giemsa. This technique differentially stains the constitutive heterochromatin of chromosomes 1, 9, 15, 16, and the Y. In the heterochromatin of chromoso...
journal_title:Chromosoma
pub_type: 杂志文章
doi:10.1007/BF00326317
更新日期:1975-08-11 00:00:00
abstract::The reduction in chromosome number during meiosis is essential for the production of haploid germ cells and thereby fertility. To achieve this, homologous chromosomes are first synapsed together by a protein assembly, the synaptonemal complex (SC), which permits genetic exchange by crossing over and the subsequent acc...
journal_title:Chromosoma
pub_type: 杂志文章
doi:10.1007/s00412-018-00688-z
更新日期:2019-09-01 00:00:00
abstract::The organization of interphase chromatin spans many topics, ranging in scale from the molecular level to the whole nucleus, and its study requires a concomitant range of experimental approaches. In this review, we examine these approaches, the results they have generated, and the interfaces between them. The greatest ...
journal_title:Chromosoma
pub_type: 杂志文章,评审
doi:10.1007/s00412-005-0035-3
更新日期:2006-02-01 00:00:00
abstract::Studies performed on human trisomic 21 oocytes have revealed that during meiosis, the three homologues 21 synapse and, in some cases, achieve what looks like a trivalent. This implies that meiotic recombination takes place among the three homologous chromosomes 21, and to some extent, crossovers form between them. To ...
journal_title:Chromosoma
pub_type: 杂志文章
doi:10.1007/s00412-012-0394-5
更新日期:2013-03-01 00:00:00
abstract::We describe a mammalian artificial mini-chromosome lacking human alphoid DNA and mouse minor and major satellite DNA repeats. This mini-chromosome, initially recovered in a mouse embryonic stem (ES) cell line (CGR8), is 2.6 Mb in size and consists of sequences derived from the human Y chromosome and mouse chromosomes ...
journal_title:Chromosoma
pub_type: 杂志文章
doi:10.1007/s004120100160
更新日期:2001-11-01 00:00:00
abstract::At least two types of Robertsonian exchange are now known in the acrocentric chromosomes of man. Both types involve breakage in the arms adjacent to the centromere. Evidence is presented for a third type of exchange, one involving breakage within the centromere itself, in the grasshopper Percassa rugifrons. In this sp...
journal_title:Chromosoma
pub_type: 杂志文章
doi:10.1007/BF00326262
更新日期:1975-09-26 00:00:00
abstract::BrdU-substituted Chinese hamster chromosomes were treated with a hog Na2HPO4 solution and stained with Giemsa to produce sister chromatid differential staining (SCD). The process of SCD was examined with the Nomarski differential interference microscope and the scanning electron microscope. After the Na2HPO4 treatment...
journal_title:Chromosoma
pub_type: 杂志文章
doi:10.1007/BF00285754
更新日期:1981-01-01 00:00:00
abstract::Engineered minichromosomes provide efficient platforms for stacking transgenes in crop plants. Methods for modifying these chromosomes in vivo are essential for the development of customizable systems for the removal of selection genes or other sequences and for the addition of new genes. Previous studies have demonst...
journal_title:Chromosoma
pub_type: 杂志文章
doi:10.1007/s00412-013-0403-3
更新日期:2013-06-01 00:00:00
abstract::Minute elements detected in Megaselia scalaris (Phoridae, Diptera) lack chromosome arms but carry centromeres and possess kinetochore microtubules in mitosis as well as in meiosis. These centromere-like elements (CLEs) were present in two geographically independent strains of the fly. This indicates that their origin ...
journal_title:Chromosoma
pub_type: 杂志文章
doi:10.1007/BF00357059
更新日期:1991-11-01 00:00:00
abstract::Using indirect immunofluorescence visualization techniques we investigated the distribution of RNA polymerase B (or II) and histone H1 at heat shock puff loci in Drosophila melanogaster polytene chromosomes at different times during and after heat shock. After heat treatments of from 5 to 45 min, the heat shock puff d...
journal_title:Chromosoma
pub_type: 杂志文章
doi:10.1007/BF00329465
更新日期:1978-01-16 00:00:00
abstract::Evidence is presented that chromosome ends are attached to the nuclear envelope prior to the formation of axial cores during early meiotic prophase in the grasshopper Brachystola magna. The attachment sites of distal and proximal chromosome ends are clustered in a small region of the inner nuclear envelope resulting i...
journal_title:Chromosoma
pub_type: 杂志文章
doi:10.1007/BF00292844
更新日期:1976-11-29 00:00:00
abstract::The distribution of quinacrine and protein sulphur has been compared with that of DNA in euchromatic and heterochromatic regions of mouse chromosomes stained with the fluorescent dye quinacrine, using X-ray microanalysis. Heterochromatin tends to bind relatively more quinacrine than euchromatin, and contains a greater...
journal_title:Chromosoma
pub_type: 杂志文章
doi:10.1007/BF00294059
更新日期:1985-01-01 00:00:00
abstract::One of the subjects within the meiotic field that has been actively investigated in the recent years is the temporal and functional relationships between meiotic recombination, cohesin loading and synaptonemal complex (SC) assembly. Although the study of meiotic mutants has shed some light, many questions remain to be...
journal_title:Chromosoma
pub_type: 杂志文章
doi:10.1007/s00412-009-0204-x
更新日期:2009-06-01 00:00:00
abstract::Microspore culture stimulates immature pollen grains to develop into plants via tissue culture and is used routinely in many crop species to produce "doubled haploids": homozygous, true-breeding lines. However, microspore culture is also often used on material that does not have stable meiosis, such as interspecific h...
journal_title:Chromosoma
pub_type: 杂志文章
doi:10.1007/s00412-019-00720-w
更新日期:2019-12-01 00:00:00