The meiotic prophase in Bombyx mori females analyzed by three-dimensional reconstructions of synaptonemal complexes

Chromosoma ◽  
1976 ◽  
Vol 54 (3) ◽  
pp. 245-293 ◽  
Author(s):  
S�ren Wilken Rasmussen
Keyword(s):  
Bombyx Mori ◽  
Meiotic Prophase ◽  
Three Dimensional ◽  
Synaptonemal Complexes

Elimination of multivalents during meiotic prophase in Scilla autumnalis. I. Diploid and triploid

Genome ◽  
1988 ◽  
Vol 30 (6) ◽  
pp. 930-939 ◽  
Author(s):  
J. White ◽  
G. Jenkins ◽  
J. S. Parker
Keyword(s):  
Meiotic Prophase ◽  
Three Dimensional ◽  
Low Frequency ◽  
Chiasma Formation ◽  
Root Tip ◽  
Synaptonemal Complexes ◽  
Dimensional Reconstruction ◽  
Scilla Autumnalis ◽  
Surface Spreading ◽  
Pairing Behaviour

The ultrastructure and pairing behaviour of the chromosomes of two diploid cytotypes and a triploid of Scilla autumnalis were investigated using the techniques of three-dimensional reconstruction from serial electron micrographs and whole-mount surface spreading of synaptonemal complexes. The diploids, designated AA and B7B7, have karyotypes that are virtually identical in appearance at mitotic metaphase but differ in length by 47% and in DNA content by 66%. All the chromosomes were identified during meiotic prophase in both diploids, enabling construction of accurate karyotypes, which were the same as those derived from root tip metaphases. Chromosome pairing was largely regular with very few structural chromosome rearrangements. These two observations permitted confident interpretations of multivalent configurations observed in polyploids containing multiples of the A and B7 genomes. In the triploid (AB7B7) during meiotic prophase lateral components are associated in groups of three, either as trivalents with several exchanges of pairing partners, or as bivalents and univalents in close alignment. The overall difference in length between A and B7 chromosomes is close to expected, but varies to some degree depending on the extent of pairing between the two chromosome types. Most of the synaptonemal complexes between A and B7 homoeologues are ineffective in terms of chiasma formation, as revealed by the low frequency of multivalents and heteromorphic bivalents at metaphase I. In other words, there is an elimination of multivalents during meiotic prophase in the triploid.Key words: Scilla autumnalis, synaptonemal complex, multivalents, elimination.

scholarly journals Identification of a meiosis-specific chromosome movement pattern induced by persistent DNA damage

2020 ◽  
Author(s):  
Daniel León-Periñán ◽  
Alfonso Fernández-Álvarez
Keyword(s):  
Dna Damage ◽  
Meiotic Prophase ◽  
Meiotic Chromosome ◽  
Three Dimensional ◽  
Model Organism ◽  
Movement Pattern ◽  
Time Lapse ◽  
Chromosome Movement ◽  
Nuclear Movement ◽  
Chromosome Associations

ABSTRACTAs one of the main events occurring during meiotic prophase, the dynamics of meiotic chromosome movement is not yet well understood. Currently, although it is well-established that chromosome movement takes an important role during meiotic recombination promoting the pairing between homologous chromosomes and avoiding excessive chromosome associations, it is mostly unclear whether those movements follow a particular fixed pattern, or are stochastically distributed. Using Schizosaccharomyces pombe as a model organism, which exhibits dramatic meiotic nuclear oscillations, we have developed a computationally automatized statistical analysis of three-dimensional time-lapse fluorescence information in order to characterize nuclear trajectories and morphological patterns during meiotic prophase. This approach allowed us to identify a patterned oscillatory microvariation during the meiotic nuclear motion. Additionally, we showed evidence suggesting that this unexpected oscillatory motif might be due to the detection of persistent DNA damage during the nuclear movement, supporting how the nucleus also regulates its oscillations. Our computationally automatized tool will be useful for the identification of new patterns of nuclear oscillations during gametogenesis.

The synaptonemal complexes of Achlya recurva (Oomycetes): karyotype analysis and three-dimensional reconstruction of pachytene nuclei in antheridia and oogonia

1991 ◽  
Vol 69 (6) ◽  
pp. 1384-1395 ◽  
Author(s):  
Hobart R. Williamson ◽  
Pesach Ben Yitzchak
Keyword(s):  
Synaptonemal Complex ◽  
Organizer Region ◽  
Nucleolar Organizer Region ◽  
Nucleolus Organizer Region ◽  
Three Dimensional ◽  
Central Element ◽  
Three Dimensional Reconstruction ◽  
Synaptonemal Complexes ◽  
Sequence Of Events ◽  
Dimensional Reconstruction

Fifteen synaptonemal complexes, as determined by three-dimensional reconstruction of serial, ultrathin sections, were present within both antheridial and oogonial zygotene and pachytene nuclei of the oomyceteous fungus Achlya recurva, thus n = 15. The present study represents the first complete reconstruction of synaptonemal complexes in the genus Achlya. The occurrence of both zygonema and pachynema was simultaneous in antheridia and oogonia. Pachytene nuclei of antheridia and oogonia are small, 13 μm3 in volume, and the average length of the synaptonemal complexes ranged from 1.9 to 4.4 μm. Lateral elements at zygotene ranged from 1.2 to 4.7 μm. Both ends of each synaptonemal complex were attached randomly to the nuclear envelope, so a bouquet formation was not observed at pachytene. In A. recurva, the dimensions of the synaptonemal complex were as follows: overall width = 270 nm; the lateral elements = 75 nm each in width and the central region = 120 nm. There was no central element and associated transverse filaments, which may be associated with development of alternative reproductive strategies other than amphimixis, as in nematodes. Of the 15 synaptonemal complexes present, only the one carrying the nucleolus organizer region could be clearly identified from one nucleus to the next. The nucleolar organizer region was on the average 0.75 μm from the telomere in both zygotene and pachytene nuclei. There were an average of three recombination nodules in each nucleus. Synaptonemal complexes have been reported in over 80 different species of fungi and related protista. Karyotypic evolution in the oomycetes and fungi may be the result of poly-ploidization, followed by cytogenetic diversification involving aneuploidy and differing degrees of polyploidy. Such a sequence of events could explain the apparent polyphyletic formation of this group. Key words: karyotype, Oomycetes, pachytene, synaptonemal complexes, three-dimensional reconstruction.

Modification of Thai Silk Fibroin Scaffolds by Gelatin Conjugation for Tissue Engineering

2008 ◽  
Vol 55-57 ◽  
pp. 685-688 ◽  
Author(s):  
J. Chamchongkaset ◽  
Sorada Kanokpanont ◽  
David L. Kaplan ◽  
Siriporn Damrongsakkul
Keyword(s):  
Tissue Engineering ◽  
Bombyx Mori ◽  
Silk Fibroin ◽  
Textile Industry ◽  
Three Dimensional ◽  
Biological Properties ◽  
Salt Leaching ◽  
Biological Compatibility ◽  
Salt Crystals

Silk has been used commercially as biomedical sutures for decades. Recently silk fibroin, especially from Bombyx mori silkworm, has been explored for many tissue engineering applications such as bone and cartilage due to its impressive biological compatibility and mechanical properties. In Thailand, Thai native silkworms have been long cultivated. Distinct characteristics of cocoon Thai silk are its yellow color and coarse filament. There is more sericin in Thai silk than in other Bombyx mori silks. These characteristics provide Thai silk a unique texture for textile industry. It is therefore the aim of this study to develop three-dimensional silk fibroin-based scaffolds from Thai yellow cocoon “Nangnoi-Srisaket” of Bombyx mori silkworms using salt-leaching method. To enhance the biological properties, type A gelatin, the denature form of collagen having good biocompactibility, was used to conjugate with silk fibroin scaffolds. The pore size of salt-leached silk fibroin scaffold structure represented the size of salt crystals used (600-710µm). After gelatin conjugation, gelatin was partly formed fibers inside the pores of silk fibroin scaffolds resulting in fiber-like structure with highly interconnection. Gelatin conjugation enhanced the compressive modulus of silk fibroin scaffolds by 93%. The results on in vitro culture using mouse osteoblast-like cells (MC3T3-E1) showed that gelatin conjugation could promote the cell proliferation in silk fibroin scaffolds. Moreover, the observed morphology of cells proliferated inside the scaffold after 14 days of culture showed the larger spreading area of cells on conjugated gelatin/silk fibroin scaffolds, compared to round-shaped cells on silk fibroin scaffolds. The results implied that Thai silk fibroin looked promising to be applied in tissue engineering and gelatin conjugation on Thai silk fibroin scaffolds could enhance the biological properties of scaffolds.

scholarly journals Meiotic cohesin REC8 marks the axial elements of rat synaptonemal complexes before cohesins SMC1β and SMC3

2003 ◽  
Vol 160 (5) ◽  
pp. 657-670 ◽  
Author(s):  
Maureen Eijpe ◽  
Hildo Offenberg ◽  
Rolf Jessberger ◽  
Ekaterina Revenkova ◽  
Christa Heyting
Keyword(s):  
Synaptonemal Complex ◽  
Sister Chromatid ◽  
Meiotic Prophase ◽  
S Phase ◽  
Synaptonemal Complexes ◽  
Sister Chromatids ◽  
Chromatid Cohesion ◽  
Axial Element ◽  
Striking Contrast ◽  
Metaphase I

In meiotic prophase, the sister chromatids of each chromosome develop a common axial element (AE) that is integrated into the synaptonemal complex (SC). We analyzed the incorporation of sister chromatid cohesion proteins (cohesins) and other AE components into AEs. Meiotic cohesin REC8 appeared shortly before premeiotic S phase in the nucleus and formed AE-like structures (REC8-AEs) from premeiotic S phase on. Subsequently, meiotic cohesin SMC1β, cohesin SMC3, and AE proteins SCP2 and SCP3 formed dots along REC8-AEs, which extended and fused until they lined REC8-AEs along their length. In metaphase I, SMC1β, SMC3, SCP2, and SCP3 disappeared from the chromosome arms and accumulated around the centromeres, where they stayed until anaphase II. In striking contrast, REC8 persisted along the chromosome arms until anaphase I and near the centromeres until anaphase II. We propose that REC8 provides a basis for AE formation and that the first steps in AE assembly do not require SMC1β, SMC3, SCP2, and SCP3. Furthermore, SMC1β, SMC3, SCP2, and SCP3 cannot provide arm cohesion during metaphase I. We propose that REC8 then provides cohesion. RAD51 and/or DMC1 coimmunoprecipitates with REC8, suggesting that REC8 may also provide a basis for assembly of recombination complexes.

Levels of Biogenic Amines in the Brain during Pupal and Adult Development of the Silkworm, Bombyx mori

1997 ◽  
Vol 52 (3-4) ◽  
pp. 279-282 ◽  
Author(s):  
T. Shimizu ◽  
N. Takeda ◽  
S. Yagi
Keyword(s):  
Biogenic Amines ◽  
Bombyx Mori ◽  
Electrochemical Detection ◽  
Adult Development ◽  
Metabolic Pathways ◽  
Three Dimensional ◽  
Hplc System ◽  
Wide Range ◽  
The Brain ◽  
Silkworm Bombyx Mori

AbstractLevels of a wide range of biogenic amines and related metabolites were determined in the brain of the silk­ worm, Bomby mori, during pupal and adult development using a three-dimensional HPLC system with multiple coulometric electrochemical detection.In the brain of the female adults, metabolic pathways such as tyrosine (TYR-4)->dihydroxyphenylalanine (L -DOPA)-dopamine (DA), TYR-4->tyramine (TYRA), and tryptophan (TRP)->5-hydroxytryptamine (5-HT) were identified. At this stage, 3,4-dihydroxyphenyleth-ylene (DOPAC) was also detected. Metabolic pathways of biogenic amines in the brain from pupal to adult stages are discussed.

Three-Dimensional Microscopy of the Rad51 Recombination Protein during Meiotic Prophase

1999 ◽  
Vol 11 (5) ◽  
pp. 809 ◽  
Author(s):  
Amie E. Franklin ◽  
John McElver ◽  
Ivana Sunjevaric ◽  
Rodney Rothstein ◽  
Ben Bowen ◽  
...  
Keyword(s):  
Meiotic Prophase ◽  
Three Dimensional ◽  
Recombination Protein
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