Cytogenetic analysis of first cleavage fertilized mouse eggs following in vivo exposure to ethanol shortly before and at the time of conception

Development ◽  
1987 ◽  
Vol 100 (3) ◽  
pp. 441-448
Author(s):  
G.T. O'Neill ◽  
M.H. Kaufman
Keyword(s):  
Meiotic Division ◽  
Small Proportion ◽  
Cytogenetic Analysis ◽  
Chromosome Complement ◽  
Indirect Evidence ◽  
Chromosome Constitution ◽  
Meiotic Spindle ◽  
Dilute Solution ◽  
Mouse Eggs

In this study, the chromosome constitution of mouse eggs exposed in vivo to a dilute solution of ethanol during specific stages of the first and second meiotic divisions was determined at the first cleavage mitosis. Exposure to ethanol prior to the completion of the second meiotic division induced an incidence (7–10%) of aneuploidy involving only one chromosome in 98% of malsegregation events. This investigation provides indirect evidence that ethanol may induce aneuploidy by disrupting the functioning of the meiotic spindle. Karyological analyses of chromosome spreads prepared at the first cleavage metaphase suggest that only a small proportion of the total chromosome complement may be induced to undergo malsegregation.

Probing the ultrastructure of the mitotic and meiotic spindle in eggs: An expeditious approach based on semi-thin (0.25 μm) serial sections

1983 ◽  
Vol 41 ◽  
pp. 552-555
Author(s):  
Conly L. Rieder ◽  
S. Bowser ◽  
R. Nowogrodzki ◽  
K. Ross ◽  
G. Sluder
Keyword(s):  
Small Sample Size ◽  
Small Sample ◽  
Meiotic Spindle ◽  
Serial Sections ◽  
Mitotic Apparatus ◽  
Thin Sections ◽  
Cell Cycles ◽  
Ultrastructural Studies

Eggs have long been a favorite material for studying the mechanism of karyokinesis in-vivo and in-vitro. They can be obtained in great numbers and, when fertilized, divide synchronously over many cell cycles. However, they are not considered to be a practical system for ultrastructural studies on the mitotic apparatus (MA) for several reasons, the most obvious of which is that sectioning them is a formidable task: over 1000 ultra-thin sections need to be cut from a single 80-100 μm diameter egg and of these sections only a small percentage will contain the area or structure of interest. Thus it is difficult and time consuming to obtain reliable ultrastructural data concerning the MA of eggs; and when it is obtained it is necessarily based on a small sample size.We have recently developed a procedure which will facilitate many studies concerned with the ultrastructure of the MA in eggs. It is based on the availability of biological HVEM's and on the observation that 0.25 μm thick serial sections can be screened at high resolution for content (after mounting on slot grids and staining with uranyl and lead) by phase contrast light microscopy (LM; Figs 1-2).

scholarly journals Simultaneous Assessment of Endothelial Function, Nitric Oxide Synthase Activity, Nitric Oxide–Mediated Signaling, and Oxidative Stress in Individuals with and without Hypercholesterolemia

2008 ◽  
Vol 54 (2) ◽  
pp. 292-300 ◽  
Author(s):  
Renke Maas ◽  
Edzard Schwedhelm ◽  
Lydia Kahl ◽  
Huige Li ◽  
Ralf Benndorf ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Endothelial Function ◽  
Urinary Excretion ◽  
Indirect Evidence ◽  
No Oxidation ◽  
Whole Body ◽  
Gas Chromatography Mass Spectrometry ◽  
Synthesis Rate ◽  
No Production

Abstract Background: Endothelial function is impaired in hypercholesterolemia and atherosclerosis. Based on mostly indirect evidence, this impairment is attributed to reduced synthesis or impaired biological activity of endothelium-derived nitric oxide (NO). It was the aim of this study to directly estimate and compare whole-body NO production in normo- and hypercholesterolemia by applying a nonradioactive stable isotope dilution technique in vivo. Methods: We enrolled 12 normocholesterolemic and 24 hypercholesterolemic volunteers who were all clinically healthy. To assess whole-body NO synthesis, we intravenously administered l-[guanidino-(15N2)]-arginine and determined the urinary excretion of 15N-labeled nitrate, the specific end product of NO oxidation in humans, by use of gas chromatography-mass spectrometry. In addition, we measured flow-mediated vasodilation (FMD) of the brachial artery, expression of endothelial NOS (eNOS) in platelets, plasma concentration of the endogenous NOS inhibitor asymmetric dimethylarginine (ADMA), and urinary excretion of 8-isoprostaglandin F2α (8-iso-PGF2α). Results: After infusion of l-[guanidino-(15N2)]-arginine, cumulative excretion of 15N-labeled-nitrate during 48 h was 40% [95% CI 15%–66%] lower in hypercholesterolemic than normocholesterolemic volunteers [mean 9.2 (SE 0.8) μmol vs 15.4 (2.3) μmol/l, P = 0.003]. FMD was on average 36% [4%–67%] lower in hypercholesterolemic than normocholesterolemic volunteers [6.3 (4.0)% vs 9.4 (4.6)%, P = 0.027]. Normalized expression of NOS protein in platelets was also significantly lower in hypercholesterolemic volunteers, whereas there were no significant differences in plasma ADMA concentration or urinary excretion of 8-iso-PGF2α between the 2 groups. Conclusions: This study provides direct evidence for a decreased whole body NO synthesis rate in healthy people with hypercholesterolemia.

Parthenogenesis and cytoskeletal organization in ageing mouse eggs

Development ◽  
1986 ◽  
Vol 95 (1) ◽  
pp. 131-145
Author(s):  
Michelle Webb ◽  
Sarah K. Howlett ◽  
Bernard Maro
Keyword(s):  
Critical Concentration ◽  
Metaphase Plate ◽  
Meiotic Spindle ◽  
Cytoskeletal Organization ◽  
Spindle Poles ◽  
Different Types ◽  
Mouse Egg ◽  
Parthenogenetic Embryos

The cytoskeletal organization of the mouse egg changes during ageing in vivo and in vitro. The earliest change observed is the disappearance of the microfilament-rich area overlying the meiotic spindle. This is followed by the migration of the spindle towards the centre of the egg. Finally the spindle breaks down and the chromosomes are no longer organized on a metaphase plate. This spindle disruption may result from changes in the microtubule nucleating material found at the spindle poles and from an increase in the critical concentration for tubulin polymerization. It is possible to correlate the changes in the cytoskeletal organization of the egg occurring during ageing with the different types of parthenogenetic embryos obtained after ethanol activation. These observations strengthen the hypothesis that the actin-rich cortical area that overlies the meiotic spindle forms a domain to which the meiotic cleavage furrow is restricted and provides some insights into the mechanisms by which different types of parthenogenetic embryos are generated.

Insertions of up to 17 amino acids into a region of alpha-tubulin do not disrupt function in vivo

1987 ◽  
Vol 7 (10) ◽  
pp. 3799-3805
Author(s):  
P J Schatz ◽  
G E Georges ◽  
F Solomon ◽  
D Botstein
Keyword(s):  
Amino Acids ◽  
Variable Region ◽  
Yeast Cells ◽  
Meiotic Spindle ◽  
Nuclear Movement ◽  
Yeast Saccharomyces Cerevisiae ◽  
Alpha Tubulin ◽  
Essential Components ◽  
Altered Proteins

Microtubules in yeasts are essential components of the mitotic and meiotic spindle and are necessary for nuclear movement during cell division and mating. The yeast Saccharomyces cerevisiae has two alpha-tubulin genes, TUB1 and TUB3, either of which alone is sufficient for these processes when present in a high enough copy number. Comparisons of sequences from several species reveals the presence of a variable region near the amino terminus of alpha-tubulin proteins. We perturbed the structure of this region in TUB3 by inserting into it 3, 9, or 17 amino acids and tested the ability of these altered proteins to function as the only alpha-tubulin protein in yeast cells. We found that each of these altered proteins was sufficient on its own for mitotic growth, mating, and methods of yeast. We conclude that this region can tolerate considerable variation without losing any of the highly conserved functions of alpha-tubulin. Our results suggest that variability in this region occurs because it can be tolerated, not because it specifies an important function for the protein.

scholarly journals Plasmodium vivax and Drug Resistance

2021 ◽  
Author(s):  
Puji Budi Setia Asih ◽  
Din Syafruddin
Keyword(s):  
Drug Resistance ◽  
Molecular Basis ◽  
Indirect Evidence ◽  
Antimalarial Drugs ◽  
In Vivo Studies ◽  
In Vitro Cultivation ◽  
Radical Cure ◽  
The Status

Resistance to antimalarial drugs is a threat to global efforts to eliminate malaria by 2030. Currently, treatment for vivax malaria uses chloroquine or ACT for uncomplicated P. vivax whereas primaquine is given to eliminate latent liver stage infections (a method known as radical cure). Studies on P. vivax resistance to antimalarials and the molecular basis of resistance lags far behind the P. falciparum as in vitro cultivation of the P. vivax has not yet been established. Therefore, data on the P. vivax resistance to any antimalarial drugs are generated through in vivo studies or through monitoring of antimalarial treatments in mixed species infection. Indirect evidence through drug selective pressure on the parasites genome, as evidenced by the presence of the molecular marker(s) for drug resistance in areas where P. falciparum and P. vivax are distributed in sympatry may reflect, although require validation, the status of P. vivax resistance. This review focuses on the currently available data that may represent the state-of-the art of the P. vivax resistance status to antimalarial to anticipate the challenge for malaria elimination by 2030.

scholarly journals LOSS OF PROTEINPOLYSACCHARIDES AT SITES WHERE BONE MINERALIZATION IS INITIATED

1972 ◽  
Vol 20 (4) ◽  
pp. 279-292 ◽  
Author(s):  
D. BAYLINK ◽  
J. WERGEDAL ◽  
E. THOMPSON
Keyword(s):  
Calcium Concentration ◽  
Bone Mineralization ◽  
Bone Matrix ◽  
Indirect Evidence ◽  
Experimental Conditions ◽  
Acid Polysaccharide ◽  
Major Acid ◽  
Tibial Cortex

In both ground sections and demineralized frozen sections of the rat tibial cortex, osteoid but not mature bone matrix stained for proteinpolysaccharides with the Alcian Blue and toluidine blue techniques. The loss of proteinpolysaccharide staining occurred precisely at the mineralizing front, which was identified by in vivo lead or procion markers, not only in normal animals but also in animals in which osteoid width was either increasing or decreasing. In vitro, both proteases and saccharidases abolished proteinpolysaccharide staining of osteoid. Critical electrolyte concentration and other procedures indicated that the major acid polysaccharide component in osteoid is chondroitin sulfate. Consistent with these findings, electron microprobe analyses revealed that sulfur concentration was high in osteoid but dropped abruptly as calcium concentration increased at the mineralizing front. The precise synchronization between loss of proteinpolysaccharides and onset of mineralization under various experimental conditions provides strong indirect evidence that the loss of these macromolecules is somehow involved in initiation of mineralization in bone.

Haploidy and plant breeding

1981 ◽  
Vol 292 (1062) ◽  
pp. 499-507 ◽  
Keyword(s):  
Plant Breeding ◽  
Doubled Haploids ◽  
Chromosome Complement ◽  
Basic Research ◽  
Breeding Value ◽  
Additive Variance ◽  
Ploidy Levels ◽  
Breeding Programmes ◽  
Dh Lines

A haploid is an organism that looks like a sporophyte, but has the chromosome complement of a reduced gamete. There are several ways in which haploids can occur or be induced in vivo : spontaneously, mostly associated with polyembryony, and through abnormal processes after crosses, like pseudogamy, semigamy, preferential elimination of the chromosomes of one parental species, and androgenesis. In the crops described, haploids are or are near to being used in basic research and plant breeding. The application of haploids in breeding self-pollinated crops is based on their potential for producing fully homozygous lines in one generation, which can be assessed directly in the field. Early generation testing of segregating populations is possible through haploids, because doubled haploids (DH) possess additive variance only. Haploids can also be applied in classical breeding programmes to make these more efficient through improved reliability of selection. The application of haploids in cross-pollinated crops is also based on a rapid production of DH-lines, which can be used as inbred lines for the production of hybrid varieties. By means of haploids all natural barriers to repeated selfing are bypassed. In autotetraploid crops there are two types of haploid. One cycle of haploidization leads to dihaploids; a second cycle produces monohaploids. The significance of dihaploids is in their greatly simplified genetics and breeding and in the possibility of estimation of the breeding value of tetraploid cultivars by assessing their dihaploids. The main drawback of dihaploids is their restriction to two alleles per locus. Also, after doubling, it is impossible to achieve tetra-allelism at many loci, the requirement for maximal performance of autotetraploid cultivars. Tetra-allelism can be obtained when improved dihaploids have a genetically controlled mechanism of forming highly heterozygous restitution gametes with the unreduced number of chromosomes. Monohaploids, after doubling or twice doubling, may lead to fully homozygous diploids and tetraploids. These are important for basic research, but not yet for practical application. Meiotic data of potato homozygotes at three ploidy levels are presented.

Sign in / Sign up

Export Citation Format

Share Document