| specification of positional information in retinal ganglion cells of xenopus laevis: intra-ocular control of the time of specification. | programming events in the stage 28-31 clawed frog embryo partly determine the organization of the future retinotectal map by specifying the permanent reference axes for cellular positional information in the retina. thus, when transplanted in 180 degrees -rotated orientation into a stage 27/28 orbit, an unspecified (stage 28 or younger) eye can acquire new axes and develop a normally-oriented retinotectal map, whereas a specified (stage 31 or older) eye retains its original axes and develops an ... | 1974 | 4530323 |
| major dna polymerases common to different xenopus laevis cell types. | dna polymerases from xenopus laevis oocytes, unfertilized eggs, and kidney cells grown in culture have been characterized. the same three major dna polymerase activities are present in all cell types examined. we attempt to relate the characteristics of amphibian enzymes to those of mammalian polymerases. | 1974 | 4530330 |
| collagen synthesis in xenopus oocytes after injection of nuclear rna of frog embryos. | a messenger rna fraction from polysomes of frog larvae or rna preparations from isolated nuclei of developing frog embryos were injected into growing xenopus laevis oocytes that were incubated with labeled proline. column chromatography of protein hydrolyzates revealed labeled hydroxyproline after injection of the messenger rna fraction and neurula nuclear rna, indicating that the injected material had promoted collagen synthesis. | 1972 | 4539141 |
| the rate of action of tetrodotoxin on myelinated nerve fibres of xenopus laevis and rana esculenta. | 1. the experiments were done on single ranvier nodes of xenopus laevis (voltage clamp) and rana esculenta (action potentials). rate and size of the effect of tetrodotoxin were determined by the reversible reduction of either the sodium inward current (xenopus) or of v(a), the maximum rate of rise of the action potential (rana).2. the results of tetrodotoxin block at equilibrium could be excellently fitted by assuming a one-to-one reaction between toxin molecules and sodium channels of the xenopu ... | 1973 | 4543328 |
| steroid inhibition of protein incorporation by isolated amphibian oocytes. | the relationship between blood protein (vitellogenin) incorporation and nuclear maturation was studied in individual amphibian oocytes after in vitro exposure to desoxycorticosterone acetate (doca). isolated rana pipiens oocytes were incubated in vitro with radioactively labeled oocyte yolk precursor ([(3)h]vitellogenin) obtained from estrogenized xenopus laevis. incorporation of labeled vitellogenin into the oocytes continued over a 24-h period. oocytes simultaneously exposed to doca and to lab ... | 1974 | 4544841 |
| microspectrofluorometric identification of formaldehyde induced fluorescence in hypothalamic nuclei of xenopus laevis tadpoles. | | 1974 | 4546311 |
| comparative study of the development of myosin specificity in two amphibian species (immunofluorescence-rana temporaria-xenopus laevis). | | 1972 | 4552920 |
| purification and properties of mitochondrial deoxyribonucleic acid dependent ribonucleic acid polymerase from ovaries of xenopus laevis. | | 1972 | 4559794 |
| immunological activity of transplanted spleens in xenopus laevis. | | 1972 | 4561795 |
| mitochondrial rna in xenopus laevis. i. the expression of the mitochondrial genome. | | 1972 | 4564177 |
| mitochondrial rna in xenopus laevis. ii. molecular weights and other physical properties of mitochondrial ribosomal and 4 s rna. | | 1972 | 4564178 |
| suppression of the allograft response by implants of mature lymphoid tissues in larval xenopus laevis. | | 1972 | 4564971 |
| specificity of mitochondrial and cytoplasmic ribosomes and elongation factors from xenopus laevis. | | 1973 | 4574651 |
| proteins from biologically active ribosomal subparticles of xenopus leavis. | | 1973 | 4575791 |
| the template specificities of dna polymerase in cell free lysates of xenopus laevis eggs, larvae and immature ovaries. | | 1973 | 4581490 |
| a study of the thermal stability of ribosomes and biologically active subribosomal particles. | 1. the ability of escherichia coli ribosomes to function in poly(u)-directed protein synthesis was measured at elevated temperatures by using thermostable supernatant factors from bacillus stearothermophilus. the amount of polyphenylalanine synthesized at 55 degrees c was about the same as at 37 degrees c, but the rate of synthesis was increased approximately fivefold. at 60 degrees c the activity of the ribosomes was halved. 2. e. coli ribosomes can sustain the loss of approx. 10% of the double ... | 1973 | 4584137 |
| lens differentiation from the cornea following lens extirpation or cornea transplantation in xenopus laevis. | | 1973 | 4585215 |
| induction of skin allograft tolerance during metamorphosis of the toad xenopus laevis: a possible model for studying generation of self tolerance to histocompatibility antigens. | | 1973 | 4588108 |
| specificity in deoxyribonucleic acid uptake by transformable haemophilus influenzae. | cells of haemophilus influenzae strain rd competent for genetic transformation irreversibly bound approximately five molecular fragments of h. influenzae deoxyribonucleic acid (dna) per cell; under identical conditions, dna derived from escherichia coli b was not taken up (<1 molecule per 50 cells). similarly, dna from xenopus laevis was not taken up by competent h. influenzae. of the heterologous dnas tested, only dna from h. parainfluenzae interfered with the uptake of h. influenzae dna, as ju ... | 1974 | 4597440 |
| detection of haemoglobin in red cells of xenopus laevis by immunofluorescent double labelling. | | 1974 | 4597872 |
| replication and transcription of eukaryotic dna in escherichia coli. | fragments of amplified xenopus laevis dna, coding for 18s and 28s ribosomal rna and generated by ecori restriction endonuclease, have been linked in vitro to the bacterial plasmid psc101; and the recombinant molecular species have been introduced into e. coli by transformation. these recombinant plasmids, containing both eukaryotic and prokaryotic dna, replicate stably in e. coli. rna isolated from e. coli minicells harboring the plasmids hybridizes to amplified x. laevis rdna. | 1974 | 4600264 |
| 5'-ends of ribosomal and ribosomal precursor rnas form xenopus laevis. | | 1974 | 4600324 |
| the lampbrush chromosomes of xenopus laevis (daudin). | | 1974 | 4609703 |
| the response of xenopus laevis oocytes to injected somatic nuclei soon after germinal vesicle breakdown induced in vitro. | | 1974 | 4609785 |
| ontogeny and localization of the lens crystallins in xenopus laevis lens regeneration. | | 1974 | 4618568 |
| nuclear dna content variability in xenopus laevis: a redundancy regulation common to all gene families. | | 1973 | 4621098 |
| cytochemical localization of tyrosinase activity in pigmented epithelial cells of rana pipiens and xenopus laevis larvae. | | 1972 | 4623762 |
| [identification by immunofluorescence of thyrotropic and gonadotropic cells of the hypophysis of an anourous amphibian: xenopus laevis]. | | 1972 | 4630082 |
| immune response in xenopus laevis and immunochemical properties of the serum antibodies. | | 1973 | 4631059 |
| fine structure of spermatogenesis in the south african clawed toad xenopus laevis daudin. | | 1972 | 4636020 |
| aspects of the ultrastructure of the alimentary canal and respiratory ducts in xenopus laevis larvae. | | 1972 | 4638092 |
| the reaction of the preoptic nucleus of xenopus laevis tadpoles to osmotic stimulation. a fluorescence microscopical investigation. | | 1972 | 4638294 |
| long term retention of colloidal thorium dioxide in the liver and spleen of xenopus laevis daudin. | | 1972 | 4638907 |
| analysis of histones from different tissues and embryos of xenopus laevis (daudin). i. technical problems in the purification of undegraded native total histone preparations. | | 1972 | 4642119 |
| amino acid uptake by xenopus laevis embryos: effect of triiodo-l-thyronine. | | 1972 | 4642918 |
| the role of water-regulating mechanisms in the development of the haploid syndrome in xenopus laevis. | | 1972 | 4642996 |
| [studies on the metabolism of steroid hormones in vertebrates. ix. the metabolism of (4- 14 c)testosterone in the liver of the african water frog (xenopus laevis)]. | | 1972 | 4650172 |
| [studies on metabolism of steroid hormones in vertebrates. x. metabolism of (4- 14c)estrone in liver slices of normal and of sex-converted african water frogs (xenopus laevis)]. | | 1972 | 4650173 |
| the effect of thyroxine and hypertonic environment on the enzymes of the urea cycle in xenopus laevis. | | 1972 | 4653167 |
| [biochemical research on oogenesis. 4. absence of amplification of 5 s rna and trna organizer genes in early xenopus laevis oocytes]. | | 1972 | 4654399 |
| the fine structure of the developing retina in xenopus laevis. | | 1972 | 4655323 |
| the number and activity of ribosomal rna genes in xenopus laevis embryos carrying partial deletions in both nucleolar organizers. | | 1972 | 4666750 |
| action of progesterone and related steroids on oocyte maturation in xenopus laevis. an in vitro study. | | 1972 | 4670882 |
| ribosomal rna synthesis in pre- and postgastrula embryos of xenopus laevis. | | 1972 | 4670883 |
| determination of the nucleoside triphosphate contents of eggs and oocytes of xenopus laevis. | the ribonucleotide and deoxyribonucleotide contents of eggs and oocytes of xenopus laevis were measured. eggs contained most deoxyribonucleotide in the form of triphosphates. dctp, dttp, datp and dgtp were present in similar amounts. the egg contained sufficient deoxynucleotide triphosphate to make approximately 2500 nuclei. oocytes contained less pyrimidine deoxyribonucleoside triphosphates than did eggs, and purine deoxyribonucleoside triphosphates were not detected. these differences may be c ... | 1972 | 4672799 |
| [determinism of polarity in xenopus laevis oocytes: a study with scanning and transmission electron microscopes]. | | 1972 | 4674597 |
| [biochemical research on oogenesis. v. comparison between somatic 5 s rna and oocyte 5 s rna in xenopus laevis]. | | 1972 | 4676241 |
| changes in the pigment pattern of eggs of xenopus laevis following fertilization. | | 1972 | 4676895 |
| duration of karyomitosis and cell division in cleavage divisions ii-iv in the clawed frog, xenopus laevis. | | 1972 | 4677475 |
| histone synthesis during early embryogenesis in xenopus laevis (south african clawed toad). | | 1973 | 4682997 |
| biochemical data on some organs from normal or prolactin-treated xenopus laevis (daudin) adults reared in fresh and in salt water. | | 1973 | 4689584 |
| an ultrastructural and radioautographic study of early oogenesis in the toad xenopus laevis. | | 1973 | 4689945 |
| urea response to pure osmotic stress in the aquatic total xenopus laevis. | | 1973 | 4691264 |
| neuronal locus specificity: altered pattern of spatial deployment in fused fragments of embryonic xenopus eyes. | before optic nerve outgrowth in xenopus laevis embryos, a change of state occurs in the differentiating retinal cell population which renders the cells refractory to information about subsequent changes in their positions, and commits individual ganglion cells to develop specific position-dependent properties (locus specificities) which subserve the formation of orderly retinotopic connections in the optic tectum. when different parts of eye primordia from stages before optic nerve outgrowth are ... | 1973 | 4700606 |
| the visual pigment system of xenopus laevis: tadpoles and adults. | | 1973 | 4706355 |
| establishment of a cell line (xtc-2) from the south african clawed toad, xenopus laevis. | | 1973 | 4708349 |
| ddt-like action of allethrin in the sensory nervous system of xenopus laevis. | | 1973 | 4709211 |
| role of calcium and prostaglandin (pge 1 ) in the msh-induced activation of adenylate cyclase in xenopus laevis. | | 1973 | 4712184 |
| histochemical features of hind limb development in xenopus laevis. | | 1973 | 4714935 |
| cytodynamics and ontogeny of the immune response of xenopus laevis against sheep erythrocytes. | | 1973 | 4722159 |
| studies on the assembly and secretion of a multicomponent protein. the biosynthesis of vitellogenin, an oestrogen-induced glycolipophosphoprotein. | 1. incorporation of [(32)p]p(i) and [(3)h]leucine into vitellogenin secreted in vitro by liver slices from oestrogen-treated xenopus laevis is accompanied by a 2h lag; no lag is apparent for the incorporation into total tissue protein. 2. the addition of cycloheximide was found immediately to inhibit further incorporation of radioactive leucine into total tissue protein. the incorporation into secreted vitellogenin, however, continued for 2h after the addition of cycloheximide. 3. pulse-labellin ... | 1973 | 4724585 |
| location of the genes for 5s ribosomal rna in xenopus laevis. | | 1973 | 4726606 |
| the distribution of monoamine oxidase and acetylcholinesterase in the brain of xenopus laevis tadpoles. | | 1973 | 4728847 |
| properties of the primary organization field in the embryo of xenopus laevis. iv. pattern formation and regulation following early inhibition of mitosis. | | 1973 | 4729951 |
| the distribution of monoamines in the tel-, di- and mesencephalon of xenopus laevis tadpoles, with special reference to the hypothalamo-hypophysial system. | | 1973 | 4735038 |
| nuclear pore flow rate of ribosomal rna and chain growth rate of its precursor during oogenesis of xenopus laevis. | | 1973 | 4735362 |
| cortical granules remaining after fertilization in xenopus laevis. | | 1973 | 4735367 |
| duck-haemoglobin synthesis in frog cells. the translation and assay of reticulocyte 9-s rna in oocytes of xenopus laevis. | | 1973 | 4736390 |
| nuclear transplantation with melanophores, ciliated epidermal cells, and the established cell-line a-8 in xenopus laevis. | | 1973 | 4736932 |
| effects of ionic concentration on permeability properties of nodal membrane in myelinated nerve fibres of xenopus laevis. potential clamp experiments. | | 1973 | 4737548 |
| the distribution of sodium and potassium in amphibian embryos during early development. | 1. intracellular and intercellular concentrations of sodium and potassium have been measured in pregastrular embryos of xenopus laevis and amblystoma mexicanum. calcium and magnesium contents have also been determined.2. between egg and gastrula stages of development the potassium concentration is near to 60 m-mole/l. embryo. up to the blastula stage the sodium concentration is near to 50 m-mole/l. embryo; the amount of sodium in the embryo begins to fall just before gastrulation.3. embryo calci ... | 1973 | 4737869 |
| intracellular and intercellular potentials in the early amphibian embryo. | 1. the sensitivity of the membrane potential of cells of early embryos of xenopus laevis to variations in the extracellular concentrations of sodium and potassium has been determined.2. alterations in the extracellular sodium concentration have little effect on the membrane potential at all pregastrular stages tested.3. up to the 32 cell stage an increase in the concentration of potassium in the bathing medium causes a fall in cell membrane potential only when membrane newly synthesized in the f ... | 1973 | 4737870 |
| changes in lactate dehydrogenase isozyme pattern during the development of xenopus laevis (daudin). | | 1973 | 4748109 |
| assay, purification, properties and mechanism of action of gamma-glutamylcysteine synthetase from the liver of the rat and xenopus laevis. | 1. an improved radioassay for glutathione synthetase and gamma-glutamylcysteine synthetase was developed. 2. xenopus laevis liver gamma-glutamylcysteine synthetase was purified 324-fold by saline-bicarbonate extraction, protamine sulphate precipitation, cm-cellulose and deae-cellulose column chromatography, and gel filtration. 3. rat liver gamma-glutamylcysteine synthetase was purified 11400-fold by a procedure similar to that employed for the xenopus laevis enzyme. 4. rat liver gamma-glutamylcy ... | 1973 | 4748828 |
| growth and differentiation during metamorphosis of xenopus laevis. | | 1973 | 4750377 |
| 5 s dnas of xenopus laevis and xenopus mulleri: evolution of a gene family. | | 1973 | 4754843 |
| absence of cell mobility across the retina in xenopus laevis embryos. | | 1973 | 4759113 |
| reiterated transfer rna genes of xenopus laevis. | | 1973 | 4760135 |
| clustering of transfer rna genes of xenopus laevis. | | 1973 | 4760136 |
| histological development of the cement gland in xenopus laevis: a light microscopic study. | | 1973 | 4760636 |
| control of 5s rna synthesis during early development of anucleolate and partial nucleolate mutants of xenopus laevis. | ribosomes of all eukaryotes contain a single molecule of 5s, 18s, and 28s rna. in the frog xenopus laevis the genes which code for 18s and 28s rna are located in the nucleolar organizer, but these genes are not linked to the 5s rna genes. therefore the synthesis of the three ribosomal rnas provides a model system for studying interchromosomal aspects of gene regulation. in order to determine if the synthesis of the three ribosomal rnas are interdependent, the relative rate of 5s rna synthesis wa ... | 1973 | 4761330 |
| the development of a hypothalamic monoaminergic system for the regulation of the pars intermedia activity in xenopus laevis. | | 1973 | 4761512 |
| properties of the primary organization field in the embryo of xenopus laevis. v. regulation after removal of the head organizer, in normal early gastrulae and in those already possessing a second implanted organizer. | | 1973 | 4761667 |
| effects of adenohypophysectomy and aminoglutethimide on water and electrolyte composition of xenopus laevis daudin. | | 1973 | 4761690 |
| an electron microscope study of acid hydrolase activity in the pneumonocytes of xenopus laevis. | | 1973 | 4762899 |
| preferential transcription of xenopus laevis ribosomal rna in interspecies hybrids between xenopus laevis and xenopus mulleri. | | 1973 | 4763983 |
| ionic currents at resting potential in nerve fibres from xenopus laevis. potential clamp experiments. | | 1973 | 4765596 |
| the effect of long-term exposure to an illuminated white background on the msh content of the pituitary of xenopus laevis. | | 1973 | 4770273 |
| mycobacteria and lymphoreticular tumours in xenopus laevis, the south african clawed toad. i. isolation, characterization and pathogenicity for xenopus of m. marinum isolated from lymphoreticular tumour cells. | | 1973 | 4770465 |
| mycobacteria and lymphoreticular tumours in xenopus laevis, the south african clawed toad. ii. have mycobacteria a role in tumour initiation and development? | | 1973 | 4770466 |
| sequence organization in the genome of xenopus laevis. | | 1973 | 4782889 |
| isolation and structure of a new active peptide "xenopsin" on the smooth muscle, especially on a strip of fundus from a rat stomach, from the skin of xenopus laevis. | | 1973 | 4783175 |
| [biochemical research on cogenesis. 6. properties of 5s rna present in the different cellular compartments of xenopus laevis oocytes]. | | 1973 | 4785224 |
| the action of cytochalasin b during egg cleavage in xenopus laevis: dependence on cell membrane permeability. | | 1973 | 4787185 |
| quantitative and qualitative analysis of rna synthesis in stage 6 and stage 4 oocytes of xenopus laevis. | | 1973 | 4787598 |
| synthesis of mitochondrial rna in disaggregated embryos of xenopus laevis. | | 1973 | 4789599 |
| the development of the optic tectum in xenopus laevis: a golgi study. | | 1973 | 4791391 |
| analysis of histones from different tissues and embryos of xenopus laevis (daudin). ii. qualitative and quantitative aspects of nuclear histones during early stages of development. | | 1973 | 4792195 |
| a study of the dissociation of the ribosomes of xenopus laevis at various stages of development. | | 1973 | 4797001 |
| [biochemical research on oogenesis. 7. synthesis and maturation of 5s rna in the small oocytes of xenopus laevis]. | | 1973 | 4799005 |