Characterization of glucose transport in preimplantation mouse embryos

1995 ◽  
Vol 7 (1) ◽  
pp. 41 ◽  
Author(s):  
HG Gardner ◽  
PL Kaye
Keyword(s):  
Glucose Transporter ◽  
Cytochalasin B ◽  
Cell Stage ◽  
Preimplantation Mouse Embryos ◽  
Uterine Fluid ◽  
Preimplantation Mouse ◽  
Morula Stage ◽  
Increased Activity ◽  
External Glucose

Membrane transport of glucose divorced from metabolism, was analysed in 2-cell embryos, morulae and blastocysts in the preimplantation mouse. A non-metabolizable radiolabelled analogue, 3,0 methyl D-glucose (3OMG) was used, and glucose was used as well in morulae and blastocysts; incubation times were < or = 5 min. Uptake occurred by combination of a non-saturable process, resistant to cytochalasin-B, and a facilitated process exhibiting classic Michaelis-Menten kinetics. The rate constant for the non-saturable component increased from 1.22 +/- 0.12 pL embryo-1 min-1 in 2-cell embryos to 2.08 +/- 0.44 pL embryo-1 min-1 in blastocysts, determined using 3OMG. The Km values of the saturable component for 3OMG at 22 degrees C were relatively constant at about 6.5 mM in 2-cell embryos, morulae and blastocysts. At 37 degrees C, the Km increased from 6 mM in 2-cell embryos to 17 mM in blastocysts. Vmax increased about five-fold during development from the 2-cell stage to the morula stage and about three-fold during development to the blastocyst. The Km values for glucose in morulae and blastocysts were constant at about 1.3 mM at 37 degrees C. Uptake of 3OMG in blastocysts was inhibited by glucose and stimulated by incubation in glucose-free medium. There was no kinetic evidence for the participation of multiple saturable components in uptake by blastocysts or morulae. This supports the observation that the glucose transporter GLUT2, which is first expressed at the 8-cell stage to supplement GLUT1 expressed in the oocyte, does not contribute to the uptake of environmental glucose and is, therefore, probably restricted in expression to abcoelic membrane areas of the trophectoderm. Together with the known values of glucose in uterine fluid, the kinetic data indicate that most glucose enters the trophectoderm by this GLUT1 at a rate which directly reflects the external glucose concentrations. The activity increased on a cellular basis as development proceeded, suggesting increased activity to meet the increasing metabolic requirements of the blastocyst for glucose.

Participation of glucose in the synthesis of glycoproteins in preimplantation mouse embryos

1990 ◽  
Vol 2 (1) ◽  
pp. 35 ◽  
Author(s):  
RG Wales ◽  
J Hunter
Keyword(s):  
Incubation Medium ◽  
Lactate Production ◽  
Glycogen Storage ◽  
High Concentration ◽  
Cell Stage ◽  
Glucose Carbon ◽  
Preimplantation Mouse Embryos ◽  
Preimplantation Mouse ◽  
Morula Stage ◽  
Qualitative Changes

Electrophoretic separation of solubilized embryos incubated for 24 h in the presence of [U-14C]glucose indicated incorporation of glucose carbon into a number of protein bands. Treatment of nitrocellulose blots of electrophoretograms with glucosidases had no effect on incorporated counts, confirming that the labelled bands were not due to protein bound glycogen. Furthermore, addition of 0.1 microgram mL-1 tunicamycin to the incubation medium virtually eliminated incorporation of glucose into the protein bands but had no effect on the pattern or rate of incorporation of labelled amino acids in parallel experiments. Also the pattern of labelling of protein by glucose was reflected in the pattern of binding of Con A to the nitrocellulose blots. There were quantitative and qualitative changes in labelling as development progressed. For embryos cultured from the 2-cell stage, a small amount of label was incorporated in two major bands at relative mobility (Mr) 69 and 97 K. With culture from the 8-cell stage, three additional major bands (33, 44 and 56 K) were labelled. Embryos cultured from the morula stage showed a different profile of incorporation; there was much more active labelling, and eight major and a number of minor radioactive bands were identified. Whilst tunicamycin suppressed glucose incorporation into glycoproteins and inhibited compaction of embryos, it had little effect on other parameters of metabolism during incubation in its presence for 24 h. No significant effects of the metabolite on protein synthesis, glycogen storage, lactate production or overall macromolecular synthesis were evident. By contrast, the anabolic metabolism of embryos decompacted by long periods of exposure to tunicamycin was severely reduced although glycolysis was still unaffected. Amphomycin at very high concentration (500 micrograms mL-1) was toxic to embryos but at concentrations up to 250 micrograms mL-1 had no effect on compaction and development of blastocysts. Addition of monensin to the incubation medium [16 micrograms mL-1] did not interfere with the development of either 2-cell or 8-cell embryos to blastocysts.

Disruption of the cytokeratin filament network in the preimplantation mouse embryo

Development ◽  
1988 ◽  
Vol 104 (2) ◽  
pp. 219-234
Author(s):  
J.A. Emerson
Keyword(s):  
Mouse Embryo ◽  
Blastocyst Stage ◽  
Cell Stage ◽  
Trophectoderm Cells ◽  
Preimplantation Mouse Embryos ◽  
Preimplantation Mouse Embryo ◽  
Preimplantation Mouse ◽  
Morula Stage ◽  
Cytokeratin Filaments

The distribution of the cytokeratin network in the intact preimplantation mouse embryo and the role of cytokeratin filaments in trophectoderm differentiation were investigated by means of whole-mount indirect immunofluorescence microscopy and microinjection of anti-cytokeratin antibody. Assembled cytokeratin filaments were detected in some blastomeres as early as the compacted 8-cell stage. The incidence and organization of cytokeratin filaments increased during the morula stage, although individual blastomeres varied in their content of assembled filaments. At the blastocyst stage, each trophectoderm cell contained an intricate network of cytokeratin filaments, and examination of sectioned blastocysts confirmed that extensive arrays of cytokeratin filaments were restricted to cells of the trophectoderm. Microinjection of anticytokeratin antibody into individual mural trophectoderm cells of expanded blastocysts resulted in a dramatic rearrangement of the cytokeratin network in these cells. Moreover, antibody injection into 2-cell embryos inhibited assembly of the cytokeratin network during the next two days of development. Despite this disruption of cytokeratin assembly, the injected embryos compacted and developed into blastocysts with normal morphology and nuclear numbers. These results suggest that formation of an elaborate cytokeratin network in preimplantation mouse embryos is unnecessary for the initial stages of trophectoderm differentiation resulting in blastocyst formation.

X-chromosome activity in preimplantation mouse embryos from XX and XO mothers

Development ◽  
1978 ◽  
Vol 46 (1) ◽  
pp. 53-64
Author(s):  
Marilyn Monk ◽  
Mary Harper
Keyword(s):  
X Chromosome ◽  
Bimodal Distribution ◽  
Mouse Embryos ◽  
Activity Levels ◽  
Cell Stage ◽  
X Chromosomes ◽  
Preimplantation Mouse Embryos ◽  
Preimplantation Mouse ◽  
Morula Stage ◽  
The Mean

Embryos from XO female mice begin development with half the activity levels of an enzyme (HPRT) coded for by a gene on the X chromosome, compared with embryos from XX females. Groups of unfertilized eggs and individual embryos at the 8-cell, morula and blastocyst stages were assayed for HPRT activity. An autosomally coded enzyme (APRT) was assayed simultaneously in the same reaction mix as a control. There is a substantial increase in HPRT activity by the 8-cell stage. However, the mean activity of HPRT in embryos of XO mothers remains half that in embryos of XX mothers. This suggests a significant maternally inherited component of HPRT activity in 8-cell embryos. By the 9- to 16-cell morula stage the HPRT activities in the two groups of embryos become similar due, presumably, to a transition to embryo-coded activity; HPRT activities in individual morulae from XX mothers show a bimodal distribution consistent with the hypothesis that both X-chromosomes are active in XX embryos at this stage.

Human Adenovirus Uptake by Preirnplantation Mouse Embryos

1972 ◽  
Vol 30 ◽  
pp. 268-269
Author(s):  
D. G. Chase ◽  
W. Winters ◽  
L. Piko
Keyword(s):  
Hela Cells ◽  
Human Adenovirus ◽  
Mouse Embryos ◽  
Equilibrium Density ◽  
Cell Stage ◽  
Virus Attachment ◽  
Preimplantation Mouse Embryos ◽  
Embryo Culture Medium ◽  
Preimplantation Mouse ◽  
Mouse Cells

Although the outlines of human adenovirus entry and uncoating in HeLa cells has been clarified in recent electron microscope studies, several details remain unclear or controversial. Furthermore, morphological features of early interactions of human adenovirus with non-permissive mouse cells have not been extensively documented. In the course of studies on the effects of human adenoviruses type 5 (AD-5) and type 12 on cultured preimplantation mouse embryos we have examined virus attachment, entry and uncoating. Here we present the ultrastructural findings for AD-5.AD-5 was grown in HeLa cells and purified by successive velocity gradient and equilibrium density gradient centrifugations in CsCl. After dialysis against PBS, virus was sedimented and resuspended in embryo culture medium. Embryos were placed in culture at the 2-cell stage in Brinster's medium.

scholarly journals Effects of embryo culture on global pattern of gene expression in preimplantation mouse embryos

Reproduction ◽  
2004 ◽  
Vol 128 (3) ◽  
pp. 301-311 ◽  
Author(s):  
Paolo Rinaudo ◽  
Richard M Schultz
Keyword(s):  
Gene Expression ◽  
Preimplantation Embryos ◽  
Expression Analysis Systematic Explorer ◽  
Cell Stage ◽  
Global Pattern ◽  
Preimplantation Mouse Embryos ◽  
Preimplantation Mouse ◽  
Global Patterns ◽  
The One

Culture of preimplantation embryos affects gene expression. The magnitude of the effect on the global pattern of gene expression, however, is not known. We compared global patterns of gene expression in blastocysts cultured from the one-cell stage in either Whitten’s medium or KSOM + amino acids (KSOM/AA) with that of blastocysts that developed in vivo, using the Affymetrix MOE430A chip. The analysis revealed that expression of 114 genes was affected after culture in Whitten’s medium, whereas only 29 genes were mis-expressed after culture in KSOM/AA. Expression Analysis Systematic Explorer was used to identify biological and molecular processes that are perturbed after culture and indicated that genes involved in protein synthesis, cell proliferation and transporter function were down-regulated after culture in Whitten’s medium. A common set of genes involved in transporter function was also down-regulated after culture in KSOM/AA. These results provide insights as to why embryos develop better in KSOM/AA than in Whitten’s medium, and highlight the power of microarray analysis to assess global patterns of gene expression.

Molecular and functional characterization and tissue localization of 2 glucose transporter homologues (TGTP1 and TGTP2) from the tapeworm Taenia solium

Parasitology ◽  
1998 ◽  
Vol 117 (6) ◽  
pp. 579-588 ◽  
Author(s):  
D. RODRÍGUEZ-CONTRERAS ◽  
P. J. SKELLY ◽  
A. LANDA ◽  
C. B. SHOEMAKER ◽  
J. P. LACLETTE
Keyword(s):  
Glucose Transporter ◽  
Cytochalasin B ◽  
Functional Characterization ◽  
Taenia Solium ◽  
Cdna Clones ◽  
Facilitated Diffusion ◽  
Porcine Cysticercosis ◽  
Isolation And Characterization ◽  
Hexose Uptake

Tapeworms absorb and consume large quantities of glucose through their syncytial tegument, storing the excess as glycogen. Although some studies on the metabolism of glucose in several tapeworms are available, the proteins that mediate its uptake and distribution in their tissue have not been identified. We describe the isolation and characterization of cDNA clones encoding 2 facilitated diffusion glucose transporters (TGTP1 and TGTP2) from Taenia solium, the causal agent of human and porcine cysticercosis. Radio-isotope labelled hexose uptake mediated by TGTP1 expressed in Xenopus oocytes is inhibited by the natural stereoisomers d-glucose and d-mannose but not by l-glucose. Transport by TGTP1 is sensitive to classical inhibitors of facilitated diffusion such as phloretin and cytochalasin B, and insensitive to ouabain. TGTP2 did not function in Xenopus oocytes. Localization studies using specific anti-TGTP1 and anti-TGTP2 antibodies show that TGTP1 is abundant in a number of structures underlying the tegument in adult parasites and larvae, whereas TGTP2 appears to be localized only on the tegumentary surface of the larvae and is not detected in adults.

scholarly journals Changes in responsiveness of preimplantation mouse embryos to serum

Development ◽  
1978 ◽  
Vol 45 (1) ◽  
pp. 295-301
Author(s):  
Simon B. Fishel ◽  
M. Azim H. Surani
Keyword(s):  
Bovine Serum ◽  
Rna Synthesis ◽  
Blastocyst Stage ◽  
Mouse Embryos ◽  
The Other ◽  
Cell Stage ◽  
Preimplantation Mouse Embryos ◽  
Preimplantation Mouse ◽  
Serum Albumen

Changes in uptake of radioactive uridine and its incorporation into RNA were determined in preimplantation mouse embryos, from the 2-cell to the blastocyst stage, as a measure of their responsiveness to extracellular conditions. Two media were tested, one contained serum and the other contained bovine serum albumen as a control. An increase in the acid-soluble pool occurred at the 8-cell stage and a marked increase in RNA synthesis occurred at the early blastocyst stage when the embryos were incubated with serum.

Cell membrane regions in preimplantation mouse embryos

Development ◽  
1980 ◽  
Vol 59 (1) ◽  
pp. 89-102
Author(s):  
L. Izquierdo ◽  
T. López ◽  
P. Marticorena
Keyword(s):  
Enzyme Activity ◽  
Cell Membrane ◽  
Light And Electron Microscopy ◽  
Enzyme Reaction ◽  
Mouse Embryos ◽  
Cell Stage ◽  
Preimplantation Mouse Embryos ◽  
Preimplantation Mouse ◽  
Cortical System ◽  
Crystalloid Bodies

Cell membrane regions characterized by alkaline phosphatase activity are described in cleaving mouse embryos and early blastocysts. Enzyme activity is demonstrated by light and electron microscopy, from the late 4-cell stage onwards, on the cell surfaces between blastomeres but not on the outer surface of the embryo. Experiments with dissociated morulae show that this is probably not an artifact due to the retention of the enzyme reaction product between the blastomeres. With the electron microscope the activity is also demonstrated in crystalloid bodies within the cytoplasm. The localization and growth during cleavage of cell membrane regions with enzyme activity is interpreted as the result of new cell membrane formation and/or as a relation of the crystalloid bodies with the cell membrane through the cortical system of microtubules and filaments.

Sign in / Sign up

Export Citation Format

Share Document