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At least 595 records · Page 33Linked to original sources
PubMed1987

Effect of varying glycerol and sucrose concentration combinations on embryo survival rate in a one-step cryoprotectant removal from frozen-thawed ovine embryos.

Two hundred fifty-one ovine embryos were frozen in different levels of glycerol (1.0, 1.4, 2.0 or 2.8M) and thawed into one of four sucrose levels (0, 0.25, 1.0 or 2.0M) to determine the optimal glycerol-sucrose combination for one-step, in-straw thawing. Sucrose was toxic at low glycerol levels and mandatory at high levels. The 1.0M sucrose level with either 1.4 or 2.0M glycerol was optimal for one-step cryoprotectant removal.

Journal Article↗
PubMed1991

Embryo transfer as a means of controlling the transmission of viral infections. XIII. Failure to transmit foot-and-mouth disease virus through the transfer of embryos from viremic donors.

A total of 436 embryos/unfertilized ova was collected from 30 foot-and-mouth disease (FMD) viremic cattle; 106 of these embryos/ova were from eight donors that had FMD virus in their reproductive tracts. The 436 embryos/ova were washed and then either assayed in cell culture or intradermally in steer tongues or transferred to recipients. Foot-and-mouth infectivity was not found to be associated with any of the embryos/ova assayed in cell culture or intradermally. The 149 embryos transferred produced two abortions, five sets of twins born prematurely, and 15 normal calves. All of the recipients and all of the calves remained FMD-seronegative.

Journal Article↗
PubMed2002

Reproductive semi-cloning respecting biparental embryo origin: embryos from syngamy between a gamete and a haploidized somatic cell.

Embryos formed by somatic cell nuclear transfer to enucleated oocytes (cloning) have given rise to viable offspring in several mammalian species. The possibility of future application of this technique to human assisted reproduction (reproductive cloning) has been widely debated. On this background there is current discussion of the potential for a cloning-derived technique, which aims at syngamy between a gamete nucleus from one parent and a somatic cell nucleus from the other. Critical analysis of the clinical indications, the current state of the art, biological concerns and ethical considerations relative to this technique, called here reproductive semi-cloning, are presented. Such a technique requires validation by further research before it can be considered as a treatment option. This debate explores issues raised by the technique.

Animals↗
PubMed1984

Studies on perivitelline fluid of horseshoe crab embryo. I. Purification and properties of agglutinin from the perivitelline fluid of Tachypleus gigas embryo.

Agglutinin in the perivitelline fluid (PVF) of Tachypleus gigas, horseshoe crab, embryo was isolated and purified by a combination of affinity column chromatography on Sepharose 4B coupled with bovine submaxillary gland mucin and gel-filtration of Fractogel TSK (Toyopearl) HW-60 in Tris-NaCl-CaCl2 (0.05 M Tris-HCl, pH 7.5, containing 0.5 M NaCl and 0.1 M CaCl2) buffer, containing 1 M urea. The specific activity of the purified protein was increased about 1,300 times in comparison with that of the starting material. The active protein was present in highly polymerized forms which were multimers of an identical subunit with a molecular weight of approximately 40,000 as measured by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. This agglutinin was shown to have multimeric activity towards different kinds of erythrocytes and its hemagglutinating activity was inhibited by N-acetylamino sugars and bovine submaxillary gland mucin containing sialic acid. Urea and guanidine-HCl inhibited the agglutinating activity but the activity recovered after dilution or dialysis, whereas the effect of HCl, NaOH, or 2-mercaptoethanol was irreversible.

Animals↗
PubMed1984

Studies on perivitelline fluid of horseshoe crab embryo. II. Purification of agglutinin-binding substance from the perivitelline fluid of Tachypleus gigas embryo.

Three glycoproteins with potent agglutinin-binding activity have been isolated from the perivitelline fluid of Tachypleus gigas, horseshoe crab, embryo. In the native form, these agglutinin-binding substances were highly aggregated. After being dissociated in 10 M urea, these proteins were fractionated by gel-filtration on a Fractogel TSK (Toyopearl) HW-60 in Tris-NaCl-CaCl2 (0.05 M Tris-HCl, pH 7.5, containing 0.5 M NaCl and 0.1 M CaCl2) containing 10 M urea. The proteins thus obtained were designated as ABS-I, -II, and -III in the order of elution and have apparent molecular weights of 25,000 (ABS-II) and 10,000 (ABS-III) as judged by both gel-filtration on Fractogel TSK (Toyopearl) HW-60 in 10 M urea and sodium dodecyl sulfate-gel electrophoresis; the molecular weight of ABS-I could not be estimated in the two systems since it was too high. ABS-I, -II, and -III, of which only ABS-I is water-soluble, inhibit one hemagglutination unit of activity with minimum quantities of 0.5 micrograms/ml, 7.8 micrograms/ml, and 1.0 micrograms/ml, respectively. They were found to be glycoproteins in which 6.6% of the dry weight (ABS-I), 4.2% of the dry weight (ABS-II), and 7.5% of the dry weight (ABS-III) were carbohydrate. The dry weight ratio of hexosamines in these substances is 3:1:2 (ABS-I: ABS-II: ABS-III), and that of sialic acid is also 3:1:2. Amino acid analyses of these proteins indicated that they have high contents of aspartic acid, glutamic acid, and glycine in common.

Amino Acids↗
PubMed2004

Isolation of putative glycoprotein gene from early somatic embryo of carrot and its possible involvement in somatic embryo development.

Somatic embryogenesis is a unique process in plant cells. For example, embryogenic cells (EC) of carrot (Daucus carota) maintained in a medium containing 2,4-dichlorophenoxyacetic acid (2,4-D) regenerate whole plants via somatic embryogenesis after the depletion of 2,4-D. Although some genes such as C-ABI3 and C-LEC1 have been found to be involved in somatic embryogenesis, the critical molecular and cellular mechanisms for somatic embryogenesis are unknown. To characterize the early mechanism in the induction of somatic embryogenesis, we isolated genes expressed during the early stage of somatic embryogenesis after 2,4-D depletion. Subtractive hybridization screening and subsequent RNA gel blot analysis suggested a candidate gene, Carrot Early Somatic Embryogenesis 1 (C-ESE1). C-ESE1 encodes a protein that has agglutinin and S-locus-glycoprotein domains and its expression is highly specific to primordial cells of somatic embryo. Transgenic carrot cells with reduced expression of C-ESE1 had wide intercellular space and decreased polysaccharides on the cell surface and showed delayed development in somatic embryogenesis. The importance of cell-to-cell attachment in somatic embryogenesis is discussed.

2,4-Dichlorophenoxyacetic Acid↗
PubMed1985

Reactivity of five N-acetylgalactosamine-recognizing lectins with preimplantation embryos, early postimplantation embryos, and teratocarcinoma cells of the mouse.

The expression of receptors for N-acetylgalactosamine-recognizing lectins, namely Helix pomatia agglutinin (HPA), Sophora japonica agglutinin (SJA), Bauhinia purpurea agglutinin (BPA), Vicia villosa agglutinin (VVA), and Wistaria floribunda agglutinin (WFA) was studied in early mouse embryos and teratocarcinoma cells. Each of these lectins as well as Dolichos biflorus agglutinin (DBA) bound differently to early embryonic cells, with the exception of VVA and WFA which showed indistinguishable reactivities. SJA reacted intensely with visceral endoderm, but hardly at all with parietal and primitive endoderm. Therefore, SJA will be useful for analyzing the mechanism of visceral-endoderm formation. Furthermore, the inner cell mass (ICM) of early blastocysts reacted intensely with DBA, while the ICM of late blastocysts reacted only faintly with this lectin. Primary endoderm derived from the ICM reacted faintly with SJA, HPA, and DBA, and these reactivities increased again during the differentiation of the endoderm. Therefore, these three lectins could be used in the analysis of early stages during the differentiation of endoderm from the ICM. The results illustrate the highly complex nature of developmentally regulated alterations of cell-surface carbohydrates during the early stages of embryogenesis.

Acetylgalactosamine↗
PubMed1975

Wheat embryo ribonucleates. V. Generation of N2--dimethylguanylate when 'fully sequenced' homogeneous species of transfer RNA are used as substrates for wheat embryo methyltransferases.

When S-adenosly[methyl-14-C]methionine and various species of transfer RNA are used as substrates for wheat embryo methyltransferases, the principal site of guanylate-N-2 methylation can be shown to be a G-residue between the stems of the dihydrouridine and anticodon loops. This common site of guanylate-N-2 methylation is referred to as the interstem target site. 2. When the interstem target site is the non-terminal G-residue in a G-C-G-C sequence, as in the cases of Escherichia coli tRNA1-Leu, tRNA-Ile, and tRNA3-Ser, there is preponderant dimethylation to yield N-2-dimethylguanylate. 3. When the interstem target site is part of a U-C-G-U sequence, as in the case of E. coli tRNAf-Met, there is diminished dimethylation and correspondingly increased monomethylation to yield N-2-monomethylguanylate. 4. When the interstem target site is the non-terminal G-residue in an A-U-G-G sequence, as in the case of yeast tRNA-Asp, there is negligible dimethylation and almost exclusive monomethylation to yield N-2-monomethylguanylate. 5. The concerted way in which the primary, secondary, and tertiary structures of tRNA molecules might influence the efficacy of these methylations is the subject of a brief discussion. Attention is also focused on the evolutionary and molecular basis for the generally non-random distributions of methylated oligonucleotide sequences in ribosomal and transfer ribonucleates.

Base Sequence↗
PubMed1977

Fine-structural studies of the gametes and embryo of Fucus vesiculosus L. (Phaeophyta). III. Cytokinesis and the multicellular embryo.

Condensation of the chromosomes during the first cell division following fertilization of the brown alga Fucus vesiculosus L. is accompanied by the almost complete disappearance of the nuclear envelope. Golgi vesicles and other small vesicles appear within the spindle, which has paired centrioles at each end. A large amount of rough endoplasmic reticulum is in the surrounding cytoplasm during mitosis, and many vesicles at the spindle margin are encircled by stacks of endoplasmic reticulum. Annulate lamellae are observed during mitosis. The envelope which initially reforms around the chromatin in telophase has unevenly spaced nuclear pores. Cytokinesis results primarily by vesicle addition to a centripetal furrow. Mitochondria and chloroplasts concentrate around the partition site, possibly in association with microfilaments. Fibrillar material is added rapidly to the space between the daughter cells from vesicle discharge of both cells and seems to spread into the older cell wall surrounding the embryo. The rhizoid daughter cell contains numerous mitochondria and hypertrophied Golgi bodies whose vesicles increasingly pack the cell. The thallus daughter cell is packed with a variety of vesicles, and the nucleus is surrounded by many dilated cisternae of rough endoplasmic reticulum. By the four-cell stage, chloroplasts of the rhizoid cells have weakly staining lamellae, while chloroplasts of the thallus cells are actively dividing with deeply staining lamellae.

Cell Division↗
PubMed1982

Physiology of turkey embryos during pipping and hatching. IV. Thyroid function in embryos from selected hens.

Embryos from turkey hens selected for high and low hatchability were blood sampled at 24, 25, 26, 27, and 28 days of incubation. The plasma was recovered and assayed for thyroxine (T4) and triiodothyronine (T3) to observe differences in plasma T3 and T4 concentrations relative to reduced hatchability. Plasma T3 did not differ significantly between the high and low hatchability groups, but plasma T4 concentrations were significantly greater during pipping at 26 and 27 days of incubation in the high hatchability group than in the low hatchability group. No differences were observed between the T3 and T4 ratios of the high and low hatchability groups. Oxygen consumption was significantly lower in the low hatchability group than in the high hatchability group. The data indicated that hypothyroidism may be a physiological factor limiting hatchability in domestic turkeys.

Animals↗
PubMed1987

[Induction of unstable mutations in Drosophila melanogaster by microinjection of DNA from oncogenic viruses into the embryo polar plasma. I. Effect of the embryo genotype].

We have studied the spectrum and nature of mutations induced by oncogenic virus DNA injections into wsn, T-007 line of embryos, and those of the first generation hybrids obtained after crossing the T-007 line males with the Oregon R wild line females (hybrid disgenesis). Each line is shown to have a special group of "hot" sites mutating with high frequency under the effect of the oncovirus DNA injected.

Animals↗
PubMed1982

[Reconstruction of the lumbosacral plexus of an embryo at stage 23 (25mm) and an embryo at stage 16 (7,5mm)].

Two embryos, one at stage 23 and another at stage 16, are reconstructed in view of studying the evolution of the lumbosacral plexus. At stage 16, the sacral plexus begins its development with anastomosis of L5, S1 and S2 roots, while the pelvic member is scarcely sketched. At stage 23, the evolution is complete, the pelvis is entirely constitued and the femoral, sciatic and obturator nerves of adult type. The coccygian plexus is in process of construction.

Humans↗