A TECHNIQUE FOR LIGHT AND ELECTRON MICROSCOPY OF THE SYNAPTONEMAL COMPLEX OF THE MOUSE OOCYTE

1982 ◽  
Vol 24 (6) ◽  
pp. 675-680 ◽  
Author(s):  
Weng Kong Sung ◽  
Georgiana Jagiello
Keyword(s):  
Electron Microscopy ◽  
Synaptonemal Complex ◽  
Microscopic Examination ◽  
Light And Electron Microscopy ◽  
Electron Microscopic Examination ◽  
Mouse Oocyte ◽  
Electron Microscopic ◽  
Synaptonemal Complexes

A method is described for obtaining synaptonemal complex preparations from mouse pachytene oocytes for light and electron microscopic examination. A karyotype based on the whole complement of synaptonemal complexes of a pachytene oocyte as visualized by electron microscopy is presented.

Poly(ADP-ribosyl)ation of chromatin: kinetics of relaxation and its effect on chromatin solubility

1985 ◽  
Vol 63 (7) ◽  
pp. 764-773 ◽  
Author(s):  
André Frechette ◽  
Ann Huletsky ◽  
Rémy J. Aubin ◽  
Gilbert de Murcia ◽  
Paul Mandel ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Enzyme Activity ◽  
Chromatin Structure ◽  
Microscopic Examination ◽  
Electron Microscopic Examination ◽  
Histone H1 ◽  
Electrophoretic Separation ◽  
Electron Microscopic ◽  
Kinetics Of ◽  
Modified Forms

We have studied the kinetics of relaxation of poly(ADP-ribosyl)ated polynucleosomes produced by endogenous enzyme activity by comparing the generation of hyper(ADP-ribosyl)ated histone H1 and its effect on the chromatin structure as revealed by electron microscopy. A correlation can be established between the appearance of histone H1 modified forms and the localized relaxation of the chromatin. We have also noticed, in parallel, that poly(ADP-ribosyl)ated chromatin showed increased solubility in the presence of Mg2+ and 0.2 M NaCl. Electron microscopic examination of the solubilized chromatin produced by poly(ADP-ribosyl)ation shows polynucleosomes exhibiting more relaxed conformation, whereas an increasing amount of hyper(ADP-ribosyl)ated histone H1 is found in the pellet, as shown by acid–urea–polyacrylamide electrophoretic separation of histone extracts.

Electron Microscopic Observations of Purified Oat Phytochrome

1971 ◽  
Vol 29 ◽  
pp. 362-363
Author(s):  
J. T. Stasny ◽  
F. E. Mumford
Keyword(s):  
Electron Microscopy ◽  
Ammonium Sulphate ◽  
Microscopic Examination ◽  
Protein Concentration ◽  
Electron Microscopic Examination ◽  
Distilled Water ◽  
Phytochrome A ◽  
Electron Microscopic ◽  
Isolation And Purification ◽  
Molecular Dimensions

The following describes the gross morphology of purified oat phytochrome, as examined by negative staining for electron microscopy. Phytochrome, a chromoprotein important in plant photomorphogenesis, has two photoconvertible forms: PR, absorbing maximally at 664 nm and PFR at 724 nm. Although the isolation and purification of this photoreceptor has been achieved in several laboratories, its molecular dimensions have not been adequately characterized.Phytochrome was extracted from etiolated oat seedlings and purified by a previously published method. The purified oat phytochrome was prepared for electron microscopic examination by precipitation at 50 percent saturation with ammonium sulphate, followed by centrifugation at 30,000xg for 20 minutes. The resulting pellet was dissolved in twice-distilled water to give a protein concentration of approximately 200 ug/ml and then dialyzed against 1000X its volume of distilled water for 18 hours at 4°C.

Unique method of tissue culture preparation for EM

1992 ◽  
Vol 50 (1) ◽  
pp. 728-729
Author(s):  
Fen Wang ◽  
Lindsay B. Ledford ◽  
Jonathan F. Head ◽  
Robert L. Elliott
Keyword(s):  
Electron Microscopy ◽  
Tissue Culture ◽  
Cell Growth ◽  
Crystal Violet ◽  
Microscopic Examination ◽  
Culture Medium ◽  
Electron Microscopic Examination ◽  
Electron Microscopic ◽  
Unique Method ◽  
Mcf 7

A simplified technique of growing monolayer cells for electron microscopic examination has been developed. Our procedure has eliminated many difficult steps and therefore is easier than those reported by others.Regular Beem capsules for routine embedding for electron microscopy were used(Fig. 1). Prior to tissue inoculation capsules were washed with 5% HCl and gas sterilized. A 0.5 ml cell suspension of MCF-7 cells (10,000/ml) was placed in the capsules and cells settled in the pyramid portion (Fig. 2). Culture medium was alpha-MEM with 10% FCS. Capsules were incubated at 37°C for 3 days. They were then fixed in 70% ethanol for 20 minutes and stained with crystal violet. The pyramid portion of the capsule was cut off and monolayer cell growth was confirmed by examination under a microscope (Fig. 3).

Heterochromatin, the synaptonemal complex and crossing over

1984 ◽  
Vol 71 (1) ◽  
pp. 159-176 ◽  
Author(s):  
S.M. Stack
Keyword(s):  
Electron Microscopy ◽  
Lycopersicon Esculentum ◽  
Synaptonemal Complex ◽  
Electron Microscopic Examination ◽  
Differential Staining ◽  
Crossing Over ◽  
Mitotic Metaphase ◽  
Plantago Ovata ◽  
Electron Microscopic ◽  
Metaphase Chromosomes

A combined light- and electron-microscopic examination of chromosomes from two angiospermous plants, Plantago ovata and Lycopersicon esculentum, and a mammal, Mus musculus, was performed. From this investigation three observations have been made that may be relevant to the observed lack of crossing over in heterochromatin. (1) Differential staining indicates that heterochromatin represents a smaller fraction of the length of pachytene chromosomes than it represents in the length of mitotic metaphase chromosomes. Since the synaptonemal complex (SC) runs throughout the length of these pachytene chromosomes, it is under-represented in heterochromatin. Considering the evidence for a rough correlation between the length of SC and the amount of crossing over, this could result in less crossing over in heterochromatin than expected on the basis of its length in mitotic metaphase chromosomes. (2) Electron microscopy indicates that, unlike the SC in euchromatin, the SC in heterochromatin is densely ensheathed in highly compact chromatin. If crossing over occurs in the SC or even in the surrounding chromatin, the compaction of the chromatin may prevent the penetration of enzymes needed in recombination. (3) Finally, a difference in the structure of SCs in euchromatin versus heterochromatin was observed that could be associated with the lack of crossing over in heterochromatin.

Dependence on genie balance for synaptonemal complex formation in Drosophila melanogaster

Genome ◽  
1988 ◽  
Vol 30 (2) ◽  
pp. 258-264 ◽  
Author(s):  
T. M. Grishayeva ◽  
Y. F. Bogdanov
Keyword(s):  
Drosophila Melanogaster ◽  
Synaptonemal Complex ◽  
X Chromosome ◽  
Central Element ◽  
Sharp Decrease ◽  
Electron Microscopic Examination ◽  
Electron Microscopic ◽  
X Chromosomes ◽  
Ovary Cells ◽  
Synaptonemal Complexes

Electron microscopic examination of gonads of Drosophila melanogaster with different genotypes, including a metafemale 3X;2A and an intersex XXY;3A, have revealed that the formation of synaptonemal complexes is controlled by the genie balance, i.e., the ratio of X chromosomes to autosomes. The Y chromosome is not involved in the genetic control of the formation of precursors of the central element of synaptonemal complexes in males, nor does it disturb their formation in [Formula: see text] females. Hyperploidy for sections 1 – 3A and 18A – 20 of the X chromosome does not lead to the appearance of synaptonemal complexes in males and does not interfere with their formation in females. Females hyperploid for extensive regions of the X chromosome (sections 1 – 11A, 11A – 20, and 8C – 20) are fertile and show apparently normal formation of synaptonemal complexes. Hyperploidy for sections 8C – 11A of the X results in a sharp decrease in the viability of females, in abnormal differentiation of ovary cells, and in the lack of synaptonemal complexes. These data suggest a possible important role for the sections 8C – 11A in the genic balance controlling the formation of synaptonemal complexes in D. melanogaster. The lack of synaptonemal complexes in hypoploid females may be the result of abnormal cell differentiation in gonads.Key words: Drosophila melanogaster, synaptonemal complex, sex chromosomes, genic balance.

Light and electron microscope observations of a meiotic mutant of Neurospora crassa

1978 ◽  
Vol 56 (21) ◽  
pp. 2694-2706 ◽  
Author(s):  
B.C. Lu ◽  
Donna R. Galeazzi
Keyword(s):  
Electron Microscopy ◽  
Electron Microscope ◽  
Genetic Analysis ◽  
Neurospora Crassa ◽  
Synaptonemal Complex ◽  
Chromosome Pairing ◽  
Light And Electron Microscopy ◽  
Homologous Chromosomes ◽  
Synaptonemal Complexes ◽  
Nuclear Separation

Light and electron microscopy have revealed that the meiotic-1 (mei-1) mutant of Neurospora crassa is defective in chromosome pairing (asynaptic) although plenty of axial components of the synaptonemal complex are produced and occasional tripartite synaptonemal complexes can be formed. The mei-1 mutant is most probably defective in bringing the homologous chromosomes together for pairing and for assembly of the synaptonemal complex. The mei-1 mutant is also defective in nuclear separation which leads to a four-poled spindle at the subsequent division. The lack of chromosome pairing, the incomplete assembly of the synaptonemal complex, and the four-poled spindles account for absence of recombination and for the nondisjunction found in genetic analysis.

Electron microscopic examination of effects of bogma raki and walnut on cochlea

2014 ◽  
Vol 34 (3) ◽  
pp. 266-271 ◽  
Author(s):  
C Cevik ◽  
GS Ozler ◽  
C Arli ◽  
I Tatar ◽  
MF Sargon ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Drinking Water ◽  
Microscopic Examination ◽  
Spiral Ganglion ◽  
Organ Of Corti ◽  
Electron Microscopic Examination ◽  
Albino Rats ◽  
Electron Microscopic ◽  
En Bloc ◽  
Hearing Ability

Illegal alcohol beverages known as bogma raki in our country are consumed widely in our region. The studies investigating the relationship between alcohol consumption and hearing ability report different results. In this study, we aimed to investigate the toxic effects of bogma raki that contains neurotoxic substances on cochlea by electron microscopy. To the best of our knowledge, this study is the first in the literature. A total of 48 Wistar male albino rats (aged 12–16 weeks and weighing 200–240 g) were used in the study. The rats were divided into 4 groups with 12 animals in each group. The groups include control, bogma raki, walnut, and walnut + bogma raki groups. Bogma raki (30% v/v, 9.2 ml kg−1 day−1) is added to drinking water of rats in bogma raki group ( n = 12) for 4 weeks. Walnut group rats ( n = 12) are fed with standard rat food and walnut without limitation (10 g kg−1 day−1). Bogma raki + walnut group rats ( n = 12) are fed with standard rat food and walnut and bogma raki is added to drinking water. The cochleas were dissected and removed en bloc and examined by electron microscopy. Perineuronal oedema around neurons of spiral ganglion and hairy cells of organ of Corti were present in the bogma raki group, walnut group and bogma raki + walnut group under electron microscopic examination. Comparing these three groups, there were no differences in the ultrastructural pathological changes. In the ultrastructural examination of the myelinated axons forming cochlear nerve, no ultrastructural pathology was detected in all the groups.

The Synaptonemal Complex and the Achiasmatic Condition

1973 ◽  
Vol 13 (1) ◽  
pp. 83-95 ◽  
Author(s):  
S. STACK
Keyword(s):  
Light Microscopy ◽  
Microscopic Examination ◽  
Three Dimensional ◽  
Electron Microscopic Examination ◽  
Chiasma Formation ◽  
Crossing Over ◽  
Electron Microscopic ◽  
Synaptonemal Complexes ◽  
Chromosome Arrangements ◽  
Onion Species

The onion species Allium amplectans includes both a triploid and a tetraploid variety. By light microscopy both varieties appear to have normal synapsis during pachytene of meiosis. However, the triploid does not form chiasmata and exhibits almost total asynapsis following pachytene. The tetraploid forms at least one chiasma per homologue and retains pairing through metaphase I. Electron-microscopic examination of pachytene nuclei in these 2 varieties reveals apparently identical synaptonemal complexes. Three-dimensional reconstructions of chromosome arrangements in triploid pachytene nuclei confirm that synapsis is as complete as could be expected in an autotriploid. These observations give firm support to the hypothesis that the presence of apparently structurally normal synaptonemal complexes is not a sufficient prerequisite to ensure chiasma formation. It is suggested that a faulty or missing endonuclease which is normally involved in crossing over is responsible for the achiasmatic condition in triploid A. amplectans.

Imaging of the alpha-chain extensions of fibrinogen

1983 ◽  
Vol 41 ◽  
pp. 604-605
Author(s):  
Todd M. Price ◽  
M. L. Rudee
Keyword(s):  
Electron Microscopy ◽  
Amorphous Carbon ◽  
Microscopic Examination ◽  
Plasma Proteins ◽  
Polymeric Materials ◽  
Electron Microscopic Examination ◽  
Biological Materials ◽  
Mica Surface ◽  
Electron Microscopic ◽  
Alpha Chain

Amorphous carbon, as well as a few polymeric materials, are used routinely as substrates for the electron microscopic examination of macrorno1ecules. Replication of molecules from a cleaved mica surface is also used. The choice is ty pically made on the basis of convenience, and limited to commonly used materials.In the course of research on the interaction of plasma proteins with several non-biological materials we observed that the use of substrate materials that were not typical in electron microscopy produced images that revealed hitherto unobserved features of certain macromolecules. This paper will describe the techniques we have developed to image additional features of fibrinogen, give some additional results, and describe some experiments undertaken to elucidate the basis of the technique.

A Freeze-Fracture Technique for Examining Human Stratum Corneum

1972 ◽  
Vol 30 ◽  
pp. 298-299
Author(s):  
Daniel P. Hannon
Keyword(s):  
Electron Microscopy ◽  
Sample Preparation ◽  
Stratum Corneum ◽  
Microscopic Examination ◽  
Freeze Fracture ◽  
Electron Microscopic Examination ◽  
Electron Microscopic ◽  
Human Stratum Corneum ◽  
Freeze Fracture Electron Microscopy ◽  
Fracture Electron

Human stratum corneum is a difficult tissue to process for electron microscopic examination. Most of the difficulty is due to the inability of the chemical fixative to adequately preserve all of the constituents of this tissue. As a result, during sectioning, breaks occur between cells creating voids which preclude any studies of these areas. Also, because the fixative is usually in an aqueous medium, studies of hydrated or dehydrated states are impossible. However, these problems can be overcome by using an alternative method of sample preparation, freeze-fracture electron microscopy.Samples of human skin both untreated and soaked for 20 minutes in 20% glycerin were cut into strips 1 mm wide by 2 mm long and placed in specially made copper discs with a 1 mm deep central cup. Freezing was accomplished by immersion in liquid Freon 22.

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