| galactoside-binding serum lectin of xenopus laevis. estrogen-dependent hepatocyte synthesis and relationship to oocyte lectin. | xenopus laevis serum contains a lectin which binds alpha- and beta-galactosides. it was purified to homogeneity by affinity chromatography and consists of a single subunit with mr approximately 69,000, associated in a multimer. the lectin is synthesized and secreted by hepatic parenchymal cells, and its synthesis is increased about 2-fold by estrogen treatment, both in vivo and in primary cell cultures. the serum lectin has the same carbohydrate binding properties as an oocyte lectin from x. lae ... | 1985 | 4030782 |
| development of synaptic currents in immobilized muscle of xenopus laevis. | the effect of chronic immobilization on the development of synaptic currents was studied in myotomal muscle of xenopus laevis. embryos and tadpoles were immobilized by rearing them in the presence of tetrodotoxin (ttx) after removal of the egg membranes. immobilization did not affect the developmental change in duration of miniature end-plate currents (m.e.p.c.s). rise times decreased from about 3 to 0.6 ms in both immobilized and control muscle, and decay constants decreased from about 7 to 1 - ... | 1985 | 4032305 |
| alteration of the anterior-posterior embryonic axis: the pattern of gastrulation in macrocephalic frog embryos. | the production of an enlarged head or macrocephaly in frog embryos can be achieved by interspecific hybridization or by injection of the contents of the germinal vesicle (gv), the large nucleus of immature oocytes, into the blastocoels of embryos before they gastrulate. the macrocephalic embryos have large suckers and their neural tubes are larger anteriorly but smaller posteriorly as compared to controls. this abnormal syndrome has previously been thought to arise as a result of an axial struct ... | 1985 | 4038389 |
| dnase i footprinting shows three protected regions in the promoter of the rrna genes of xenopus laevis. | extracts prepared from xenopus laevis oocytes contain a protein(s) which specifically protects three discrete regions of the rna polymerase i promoter from digestion by dnase i. protected region i, from nucleotide +15 to nucleotide -10, spans the site of transcription initiation. protected region ii extends from nucleotide -70 to nucleotide -100 relative to initiation, falling within a 42-base-pair sequence which is homologous to the 60/81-base-pair repeated elements which occur outside of the p ... | 1985 | 4038778 |
| chromatin-specific hypersensitive sites are assembled on a xenopus histone gene injected into xenopus oocytes. | a cloned histone h4 gene of xenopus laevis is efficiently transcribed after injection into germinal vesicles of x. laevis oocytes. deletion analyses indicate that less than 140 base-pairs of 5' flanking sequences and 50 base-pairs of 3' flanking sequences are required for efficient transcription of this gene in xenopus oocytes. chromatin footprint analysis by a direct end-label technique reveals discrete dnase i-hypersensitive and micrococcal nuclease-hypersensitive sites at the 5' and 3' bounda ... | 1985 | 4039007 |
| the tissue-specific chicken histone h5 gene is transcribed with fidelity in xenopus laevis oocytes. | vectors containing the chicken h5 gene were micro-injected into the nucleus of xenopus laevis oocytes. transcription of the h5 gene was accurately initiated and h5 transcripts with discrete 3' termini were produced. h5 transcripts were not polyadenylated in oocyte nuclei. | 1985 | 4039008 |
| studies of a plasma membrane steroid receptor in xenopus oocytes using the synthetic progestin ru 486. | a steroid binding protein (mr = 110,000) has previously been identified in the plasma membrane of xenopus laevis oocytes by photoaffinity labeling with [3h]r5020. in order to further characterize this steroid receptor, the photoaffinity labeled receptor protein was solubilized with 0.1% brij 35. the solubilized labeled receptor yielded an approximate mol. wt of 102,000 +/- 2,000 by sucrose density gradient centrifugation, suggesting that the solubilized receptor exists as a monomer. ru 486, a sy ... | 1985 | 4039395 |
| influence of the polyamine spermine on the organization of cortical filaments in isolated cortices of xenopus laevis eggs. | microinjection of spermine into xenopus laevis eggs induces precocious furrowing, and together with known spermine-actin interactions, suggests that spermine may be affecting cortical microfilaments involved in cytokinesis. an electron microscopic study of injected eggs revealed that the ultrastructure of the induced furrows was similar to that of both artificially activated eggs and fertilized eggs. in isolated egg cortices, increasing spermine concentrations (1, 3 and 10 mm) resulted in marked ... | 1985 | 4039665 |
| spatial changes in poly(a) concentrations during early embryogenesis in xenopus laevis: analysis by in situ hybridization. | the dorsal-ventral axis of the xenopus embryo is approximately determined by the point of sperm entry, which occurs randomly about the animal-vegetal axis of the egg. two cytoplasmic components were studied whose spatial arrangements and local concentration patterns appear to reflect the forming dorsal-ventral axis. first, three-dimensional maps depicting the rearrangements of different size classes of yolk platelets were reconstructed from serial sections. these maps provide information on the ... | 1985 | 4039690 |
| characterization of a mitochondrial protein binding to single-stranded dna. | a dna-binding protein from xenopus laevis oocyte mitochondria which has been found associated with the d-loop also shows a strong preference for single-stranded dna. the binding to polynucleotides is dependent on the base composition, but no sequence specificity was found. this protein, called mtssb, binds tightly and cooperatively to single-stranded dna. by its amino-acid composition and its binding properties it appears to be similar to the single-stranded dna-binding proteins found in prokary ... | 1985 | 4039816 |
| repetitive zinc-binding domains in the protein transcription factor iiia from xenopus oocytes. | the 7s particle of xenopus laevis oocytes contains 5s rna and a 40-k protein which is required for 5s rna transcription in vitro. proteolytic digestion of the protein in the particle yields periodic intermediates spaced at 3-k intervals and a limit digest containing 3-k fragments. the native particle is shown to contain 7-11 zinc atoms. these data suggest that the protein contains repetitive zinc-binding domains. analysis of the amino acid sequence reveals nine tandem similar units, each consist ... | 1985 | 4040853 |
| pattern of protein synthesis in dissociated embryonic cells of xenopus laevis whose reaggregation was inhibited by ca2+-deprivation and by mechanical interference. | protein synthesis was studied in dissociated xenopus embryonic cells whose reaggregation was inhibited either chemically (deprivation of ca2+) or mechanically (cultivation on sintered glass filter). under reaggregation-inhibited conditions, synthesis of several proteins was inhibited in neurula but not in blastula and gastrula cells. under reaggregating conditions, pattern of protein synthesis in blastula cells became 'neurula-cell-type' after 17 h. however, under non-reaggregating conditions, a ... | 1985 | 4042162 |
| high diadenosine tetraphosphate (ap4a) level in germ cells and embryos of sea urchin and xenopus and its effect on dna synthesis. | ap4a levels in sperms, eggs and different developmental stages of sea urchin (psammechinus miliaris) and (xenopus laevis) were determined by a method based on atp measurement with luciferin/luciferase after splitting diadenosine 5',5'''-p1,p4-tetraphosphate (ap4a) into atp and amp. appreciable storage pools of ap4a were found in unfertilized eggs of psammechinus and xenopus as well as in sea urchin sperms. the actual ap4a concentration of 28 microm in sperm represents the highest ap4a level so f ... | 1985 | 4043245 |
| partial purification and characterization of mitotic factors from hela cells. | extracts from mitotic hela cells, when injected into xenopus laevis oocytes, exhibit maturation-promoting activity (mpa) as evidenced by the breakdown of the germinal vesicle and the condensation of chromosomes. in this study we have attempted to purify and characterize these mitotic factors. when 0.2 m nacl-soluble extracts of mitotic hela cells were concentrated by ultrafiltration and subjected to affinity chromatography on hydroxylapatite followed by dna-cellulose, the proteins with mpa elute ... | 1985 | 4043254 |
| retrograde degeneration of myelinated axons and re-organization in the optic nerves of adult frogs (xenopus laevis) following nerve injury or tectal ablation. | the optic nerve proximal to the lesion (toward the retina) was examined by light and electron microscopy in adult xenopus laevis after various types of injury to optic nerve fibres. intraorbital resection, transection or crush of the optic nerve or ablation of the contralateral optic tectum all resulted in marked alterations in the myelinated axon population and in the overall appearance of the nerve proximal to the site of injury. examination of the nerves from 3 days to 6 months postoperativel ... | 1985 | 4045505 |
| intermittent myelination of small-diameter sciatic axons in xenopus laevis. | nerve fibres from the sciatic nerve of apparently normal xenopus laevis were examined in teased preparations of living material and in series of cross-sections. small-diameter fibres were found that were myelinated in a spatially intermittent fashion. in these fibres, the myelinated segments were separated by long non-myelinated regions that had a 1 : 1 relationship to the investing schwann cell. it is estimated that at least 10% of the myelinated fibres with an external diameter of less than 5 ... | 1985 | 4045507 |
| oxygen binding in blood of xenopus laevis (amphibia) and evidence against root effect. | blood oxygen binding was examined in the amphibian, xenopus laevis, with the particular aim of determining whether the o2 capacity is diminished when blood ph is lowered, which is known as the root effect in blood of some fishes. hemoglobin-bound o2 concentration, [o2hb], was determined by the lex-o2-con technique, and both total hemoglobin, [hb]tot, and met-hemoglobin, [methb], contents were measured spectrophotometrically. from these measurements were calculated the oxygen capacity, o2cap, and ... | 1985 | 4048665 |
| the embryotoxic and osteolathyrogenic effects of semicarbazide. | the osteolathyrogenic agent semicarbazide was assayed for its toxicity and teratogenicity using early embryos of the frog xenopus laevis. the 96-h lc50 is 1504.20 mg/l while the 96-h ec50 is 76.28 mg/l. embryo length is altered prior to the onset of other effects indicated by a reduction in stage of development. the major malformation is associated with the notochord where the notochordal sheath is reduced owing to the disruption in the maturation and/or deposition of the connective tissue fiber ... | 1985 | 4049430 |
| (at)n is an interspersed repeat in the xenopus genome. | we have observed (at)34 and (at)23 tracts close to the coding sequences of the xenopus laevis tadpole alpha t1 and adult beta 1 globin genes, respectively. we show that (at)n sequences are found as interspersed repeats within the xenopus globin and histone gene loci. using (at)n co-polymer in filter hybridisation experiments we estimate that there are 10(4) (at)n tracts per haploid xenopus genome. hybridisation to genomic blots of dna from yeast, slime mold, trypanosome, fruit fly, salmon, chick ... | 1985 | 4054102 |
| gene-centromere mapping in xenopus laevis. | gynogenesis was used to map eight loci to their centromeres in xenopus laevis. several loci remote from their centromeres were identified. this information may be useful in distinguishing gynogenetic diploid progeny produced by suppression of second polar bodies from gynogenetic diploid progeny homozygous at all loci produced by suppression of first cleavage of gynogenetic haploids. | 1985 | 4056365 |
| association of maternal and newly synthesized ribosomes with membranous noncytoskeletal structures in xenopus laevis embryonic cells. | in xenopus laevis embryos a high concentration of both kcl and 0.5% doc (sodium deoxycholate) is needed for maximal extraction of ribosomes and polysomes. we studied the nature of the structures that keep ribosomes and polysomes immobilized within the cytoplasm of embryonic cells at cleavage through tailbud stages, using various combinations of a low-salt buffer (20 mm kcl), a high-salt buffer (500 mm kcl), 0.5% doc, and 0.5% triton x-100. with a low-salt buffer and 0.5% doc, but not triton x-10 ... | 1985 | 4056690 |
| purification and characterization of an n-acetyl-beta-d-glucosaminidase from cortical granules of xenopus laevis eggs. | the enzyme n-acetyl-beta-d-glucosaminidase was purified from the cortical granules of xenopus laevis eggs using affinity chromatography, gel filtration, and density gradient centrifugation. the enzyme had a molecular weight of 37,000-40,000 as determined by polyacrylamide gel electrophoresis and density gradient centrifugation, had a km for p-nitrophenyl-beta-d-n-acetyl-glucosaminide of 0.66 mm and a ki for glucosamine of 4.3 mm. the kinetic properties of the cortical granule enzyme were similar ... | 1985 | 4056694 |
| origin and voltage dependence of asparagine-induced depolarization in intestinal cells of xenopus embryo. | the kinetics and voltage dependence of asparagine (asn)-induced depolarization in endoderm cells from xenopus laevis embryos were analysed using current-clamp techniques. the depolarization is assumed to reflect the activation of an amino acid membrane carrier; it is accompanied by a slight increase in membrane resistance and cannot be explained by only the electrogenic character of the asn carrier. it is proposed that the asn depolarization arises, at least in part, from the decrease of the per ... | 1985 | 4057089 |
| multisensory interaction in the torus semicircularis of the clawed toad xenopus laevis. | interactions between the lateral-line, general somatosensory and auditory system were studied using field potential analysis and single unit recordings in the torus semicircularis of the clawed toad xenopus laevis. as a response to paired stimuli (electric shocks applied to the peripheral nerves or acoustic clicks), in all systems a reduction of the second evoked potential occurred for intervals of up to 5 s. following consecutive stimulation of two different systems, the amplitude of the second ... | 1985 | 4058802 |
| the development of the dendritic organization of primary and secondary motoneurons in the spinal cord of xenopus laevis. an hrp study. | during embryonic and larval development of the clawed toad, xenopus laevis, two different populations of motoneurons appear in the spinal cord. in this study the development of primary motoneurons which innervate the axial musculature (used during embryonic locomotion) and of secondary motoneurons which innervate the extremity musculature (used for locomotion during metamorphosis and thereafter) was analyzed with horseradish peroxidase (hrp) as a neuronal marker. after application of hrp to the ... | 1985 | 4061871 |
| interaction of the transplanted olfactory placode with the optic stalk and the diencephalon in xenopus laevis embryos. | the effect of olfactory placode transplantation on the differentiation of the optic vesicle and stalk has been studied in xenopus laevis embryos. host embryos (stages 23-24) received the transplant of two olfactory placodes from same-stage donors in place of a partially or totally removed optic vesicle. all tadpoles were sacrificed at stages 47-50. the host tadpoles were subdivided in three groups according to the amount of optic vesicle removed. in the first group all of the optic vesicle was r ... | 1985 | 4069358 |
| dna replication of single-stranded dna of phage fd microinjected into xenopus laevis eggs. | single-stranded circular dna of phage fd was microinjected into xenopus laevis eggs and dna synthesis was analyzed after incubation. an efficient dna synthesis occurred in the eggs: 2.7 ng of dna was newly formed in an egg whose volume is approximately 900 nl during a 5-h incubation at 20 degrees c. the dna synthesis was sensitive to aphidicolin, suggesting that dna polymerase alpha participates in the synthesis. agarose gel electrophoresis showed that full size of fd dna is synthesized and that ... | 1985 | 4074353 |
| differences of proteins in isolated egg surface after fertilization of xenopus laevis. | egg surface proteins of xenopus laevis were compared between unfertilized and fertilized egg surfaces before the first cleavage. the egg surfaces were isolated in acetone. the macromolecular compositions of egg surfaces were analyzed by two-dimensional gel electrophoresis and were shown to contain at least 30 proteins with molecular weights ranging from 27,000 to 200,000. at 50 min after fertilization, one spot with a molecular weight of 160,000 disappeared and two bands with molecular weights o ... | 1985 | 4075414 |
| timing of the initiation of rrna gene expression and nucleolar formation in cleavage embryos arrested by cytochalasin b and podophyllotoxin and in cytoplasm-extracted embryos of xenopus laevis. | the timing mechanism of rrna gene expression was studied in xenopus laevis embryos whose cleavage was arrested by treatment with cytochalasin b or podophyllotoxin, and in fertilized eggs from which about 40% of the cytoplasm was extracted by micromanipulation. rrna synthesis was activated in the cleavage-arrested embryos and also in cytoplasm-extracted embryos at the time when the control embryos commenced synthesizing rrna at the late blastula stage. formation of the nucleolar structure occurre ... | 1985 | 4075851 |
| experimental control of the site of embryonic axis formation in xenopus laevis eggs centrifuged before first cleavage. | in xenopus laevis, the dorsal structures normally develop from regions of the egg opposite the side of sperm entry. gravity is known to affect this topographic relationship in eggs inclined obliquely from their normal vertical orientation in the period before first cleavage. this effect has been explored in detail, making use of low-speed centrifugation (10-50 g) for short durations (4 min). eggs were immobilized in gelatin and oriented with their animal-vegetal axes 90 degrees to the force vect ... | 1985 | 4076537 |
| estrogen-dependent dna synthesis and parenchymal cell proliferation in the liver of adult male xenopus frogs. | estradiol-17 beta treatment of adult male xenopus laevis induces liver parenchymal cells to synthesize dna and proliferate. dna synthesis begins 3 to 4 days after estrogen treatment and continues for approximately 10 days. over this 2-week period, the total number of liver parenchymal cells increases fourfold, the wet weight of the liver remains constant, and there is a 50% reduction in cell volume. the elevated number of cells persists for several months and then returns to the control value. t ... | 1985 | 4076538 |
| characterization of the fourth component of complement in the serum of the clawed frog xenopus laevis. | the 202,000 mw protein xc, which is distinct from c3 but is essential for antibody-dependent haemolytic activity against srbc, was obtained from xenopus plasma following polyethylene glycol precipitation, ion-exchange chromatography and gel-filtration. the protein required other components of the xenopus serum in order to lyse sensitized srbc, but did not lyse unsensitized rrbc through the alternative pathway. the protein, contained at 0.17 mg/ml in the original plasma, comprised three distinct ... | 1985 | 4077103 |
| dynamics of the control of body pattern in the development of xenopus laevis. ii. timing and pattern in the development of single blastomeres (presumptive lateral halves) isolated at the 2-cell stage. | xenopus embryos have been selected in which the first cleavage plane is tending strongly to correspond with that of bilateral symmetry for the future larval pattern. the two blastomeres produced by this cleavage have been separated and allowed to develop as reciprocal pairs of presumptive lateral-half isolates. the early development and the time course of the gastrulation movements, and the qualitative and quantitative aspects of larval mesodermal patterns, have been studied in relation to synch ... | 1985 | 4078526 |
| dynamics of the control of body pattern in the development of xenopus laevis. iii. timing and pattern after u.v. irradiation of the egg and after excision of presumptive head endo-mesoderm. | a series of xenopus egg batches has been exposed to doses of u.v. (2537a) light on the vegetal hemisphere at precleavage stages, calculated to result in a range of minimal axial deficiency syndromes in the developing larvae. at the time of onset of gastrulation in synchronously fertilized but non-irradiated batch members, each experimental group was regularly scanned so that small subsamples of embryos could be set aside as showing particular, progressive degrees of delay in onset of the visible ... | 1985 | 4078527 |
| development of the lateral line system in xenopus laevis. iii. development of the supraorbital system in triploid embryos and larvae. | during normal development of the supraorbital lateral line system of xenopus, an elongated streak of primordial cells becomes subdivided into a linear series of cell groups containing only about eight cells each, thus forming a row of primary lateral line organs (winklbauer & hausen, 1983a,b). in triploid xenopus embryos, cell size is 1.5 x normal. when the formation of lateral line organs occurs in triploid primordia, the nascent organs contain only about five or six cells each, i.e. about two ... | 1985 | 4078528 |
| development of the lateral line system in xenopus laevis. iv. pattern formation in the supraorbital system. | the periodic pattern of the supraorbital lateral line organs forms in the epidermis of xenopus by the subdivision of a streak-like primordium into a linear series of small cell groups. in normal development, each such organ initially contains about 8 cells (winklbauer & hausen, 1983a,b). to see whether this initial organ size depends on the size of the streak-like primordium at the time of organ segregation, primordium size was reduced experimentally before the onset of pattern formation. in suc ... | 1985 | 4078529 |
| dynamics of the control of body pattern in the development of xenopus laevis. i. timing and pattern in the development of dorsoanterior and posterior blastomere pairs, isolated at the 4-cell stage. | xenopus embryos have been selected in which the second cleavage is occurring in a frontal plane, i.e. one tending to lie at right angles to the prospective plane of bilateral symmetry for the body pattern. some of these have been used to deduce a map of the disposition of materials for the normal mesodermal pattern (the normal 'fate map') by injecting blastomeres to found fluorescently marked clones from 4- to 32-cell stages. other such 4-cell embryos have been separated into two isolates across ... | 1985 | 4078542 |
| xenopus ribosomal gene enhancers function when inserted inside the gene they enhance. | the ribosomal dna of xenopus laevis contains repeated sequence elements in the intergenic spacer region that enhance transcription from the adjacent gene promoter (1,2). previous work has shown that these rna polymerase i enhancers influence the target promoter when they are in either orientation, at a distance of several kilobases, and only when they are in cis (3-5). in this work, we further show that enhancer activity is unaffected by inserting the enhancers within the transcription unit whos ... | 1985 | 4080555 |
| [regenerative capability in the hindlimb of xenopus laevis during ontogenetic development]. | the regenerative capacity of hindlimb of xenopus laevis was investigated by amputating the limbs at four levels in various developmental stages including younger postmetamorphosed froglets. amputations of limbs were performed at the base of limb in stages 50, 51, 52, 53, 54, 55, 58, and 60 (nieuwkoop and faber's table), at the middle of limb bud in stages 50, 51, 52 and 54, and at mid-thigh and mid-shank in stages 58 and 60, and the froglets in 2 and 3 cm in snout-vent length. in the present exp ... | 1985 | 4085572 |
| structure of the lung of the clawed toad (xenopus laevis daudin). | | 1985 | 4085945 |
| development and ciliation of the palate in two frogs, bombina and xenopus; a comparative study. | the morphological changes that occur during metamorphosis in the palates of two types of anuran larvae (a discoglossid, bombina orientalis, and a pipid, xenopus laevis) are compared. in b. orientalis the structural changes are accompanied by the ciliation of the palate epithelium. ciliation begins in the anterior region of the palate and continues in a posterior direction throughout metamorphosis. by contrast, the palate of x. laevis never becomes ciliated during its development. instead, two ci ... | 1985 | 4089862 |
| human 18 s ribosomal rna sequence inferred from dna sequence. variations in 18 s sequences and secondary modification patterns between vertebrates. | we have determined the dna sequences encoding 18 s ribosomal rna in man and in the frog, xenopus borealis. we have also corrected the xenopus laevis 18 s sequence: an a residue follows g-684 in the sequence. these and other available data provide a number of representative examples of variation in primary structure and secondary modification of 18 s ribosomal rna between different groups of vertebrates. first, xenopus laevis and xenopus borealis 18 s ribosomal genes differ from each other by onl ... | 1985 | 4091818 |
| effect of diadenosine tetraphosphate microinjection on heat shock protein synthesis in xenopus laevis oocytes. | bisnucleosides polyphosphates are thought to be chemical messengers signalling to the cell the onset of various stresses. diadenosine tri- and tetraphosphates (respectively, ap3a and ap4a) accumulate in prokaryotic and eukaryotic cells under heat shock conditions, suggesting they could trigger the synthesis of heat shock proteins (hsps). in this study, ap4a, ap3a and, as a control, ap4 (adenosine tetraphosphate) were injected into xenopus oocytes. whereas none of these compounds is able to trigg ... | 1985 | 4092696 |
| different conformations of ribosomal dna in active and inactive chromatin in xenopus laevis. | the chromatin structure of the ribosomal dna in xenopus laevis was studied by micrococcal nuclease digestions of blood, liver and embryonic cell nuclei. we have found that bgli-restricted dna from micrococcal nuclease-digested blood cell nuclei has an increased electrophoretic mobility compared to the undigested control. micrococcal nuclease digestion of liver cell nuclei causes a very slight shift in mobility, only in the region of the spacer containing the "bam islands". in contrast, the mobil ... | 1985 | 4093984 |
| [synthesis and accumulation of rna during oogenesis in xenopus laevis]. | | 1970 | 4098028 |
| rna synthesis in early oogenesis of xenopus laevis. | | 1970 | 4099172 |
| immunoglobulin classes of the clawed toad, xenopus laevis. | | 1970 | 4099437 |
| [characterization of vitelline membrane dna of xenopus laevis oocytes]. | | 1970 | 4101936 |
| [increase in organizer cistrons for 5s rna and transfer rna in small xenopus laevis oocytes]. | | 1971 | 4102791 |
| the relationship between cleavage and blastocoel formation in xenopus laevis. ii. electron microscopic observations. | | 1971 | 4105167 |
| studies on xenopus laevis immunoglobulins. | | 1971 | 4105472 |
| oogenesis in xenopus laevis (daudin). i. stages of oocyte development in laboratory maintained animals. | | 1972 | 4109871 |
| evolution of the nucleoli during oogenesis in xenopus laevis studied by electron microscopy. | | 1972 | 4111769 |
| daily variation in mitotic rate in tail-fin epidermis of larval xenopus laevis and its modification by pineal organ-subcommissural organ system and photoperiods. | | 1972 | 4113013 |
| [electron microscopic demonstration of mucoproteins in mesonephron bottle cells of the xenopus laevis daudin using phosphostungstic acid staining]. | | 1971 | 4113742 |
| characterization of yolk dna from xenopus laevis oocytes ovulated in vitro. | high molecular weight dna was isolated from the yolk platelets of xenopus laevis oocytes ovulated in vitro. yolk dna has the same buoyant density in cscl gradients as mitochondrial and nuclear dnas, and, like them, it is double-stranded. yolk dna behaves like nuclear dna, and not like mitochondrial dna, upon renaturation after denaturation. the molecules are always linear. cytochemical and biochemical controls preclude the possibility that the yolk dna might be contaminated by nuclear or mitocho ... | 1972 | 4113867 |
| response to skin allografts in xenopus laevis following thymectomy at early stages of lymphoid organ maturation. | | 1972 | 4114967 |
| chemoreception of the lateral-line organ of an aquatic amphibian, xenopus laevis. | | 1972 | 4115218 |
| some responses of the clawed toad, xenopus laevis, to soluble antigens administered in adjuvant. | | 1972 | 4117179 |
| response of the toad, xenopus laevis, to circulating antigens. cellular changes in the spleen. | | 1973 | 4119031 |
| response of the toad, xenopus laevis, to circulating antigens. responses after splenectomy. | | 1973 | 4119032 |
| ultrastructural observations on the germ line of xenopus laevis. | | 1973 | 4121365 |
| effects of arginine vasotocin on sodium and potassium metabolism in xenopus laevis after skin gland stimulation and sympathetic blockade. | | 1973 | 4123064 |
| lamellar bodies in oocytes of xenopus laevis and their relation to the mode of fixation. | | 1973 | 4125863 |
| [the synthesis of dna in oocytes of xenopus laevis]. | | 1973 | 4128294 |
| [protein kinase of ovary, ovarian oocytes and oocytes during maturation and ovulation in vitro of xenopus laevis]. | | 1973 | 4128309 |
| oogenesis in xenopus laevis (daudin). ii. the induction and subcellular localization of tyrosinase activity in developing oocytes. | | 1974 | 4131093 |
| polyacrylamide gel electrophoresis of ribosomes from different developmental stages of xenopus laevis. | | 1973 | 4133545 |
| template specificities of xenopus laevis rna polymerases. selective transcription of ribosomal cistrons by rna polymerase a. | | 1974 | 4137235 |
| the preparation of rna-directed dna polymerase from ovaries of xenopus laevis. | | 1974 | 4137289 |
| structural proteins associated with ribosomal cistrons in xenopus laevis chromosomes. | | 1974 | 4138192 |
| analysis of the c-value paradox by molecular hybridization. | poly(a)-containing rna was isolated from ovaries of xenopus laevis laevis and triturus cristatus carnifex and used as a template for the synthesis of radioactive complementary dna with rna-dependent dna polymerase. when annealed with an excess of homologous dna, the complementary dna is rendered double-stranded with kinetics that suggest that the coding sequences are single-copy in both these organisms. in triturus, these sequences are distinct from the majority of the genome, which consists of ... | 1974 | 4139720 |
| an ultrastructural study of the subcommissural organ cells of the african clawed toad, xenopus laevis. | | 1974 | 4140039 |
| the location of soluble antigen in the spleen of xenopus laevis. | | 1974 | 4140102 |
| the movement of optically detectable organelles in myelinated axons of xenopus laevis. | 1. intra-axonal organelles were detected by darkfield and nomarski microscopy in isolated myelinated nerve fibres from xenopus laevis. nerve fibres from the 8th spinal roots, the sciatic nerve, and identified motor and sensory axons from other hind limb nerves were used. the movement of the organelles was recorded either on motion picture film or by noting the times at which they crossed the lines of an ocular grid.2. three groups of organelles were detected in all fibres. a group of particles w ... | 1974 | 4140230 |
| a morphological study of the epithalamus and the thalamus of xenopus laevis. | | 1974 | 4140872 |
| studies on the adaptation of xenopus laevis to hyperosmotic media. | | 1973 | 4148982 |
| biochemical responses elicited in normal or prolactin-treated xenopus laevis (daudin) specimens by environmental changes. | | 1974 | 4149010 |
| [the action of phosphate nucleosides on oxidation of nadh in mitochondria of the xenopus laevis ovary]. | | 1973 | 4150431 |
| [rapidly labeled ribonucleic acid in xenopus laevis embryos]. | | 1964 | 4157729 |
| [behavior of the acid hydrolases in the tail of the tadpole of xenopus laevis during metamorphosis]. | | 1964 | 4157956 |
| [the chemical composition and significance of pas positive granules in the supranuclear zone of kidney tubule cells of xenopus laevis daud]. | | 1965 | 4158600 |
| [normal blood values of african clawed toad, xenopus laevis (daudin)]. | | 1965 | 4161153 |
| gene amplification in the oocyte nucleus of mutant and wild-type xenopus laevis. | | 1968 | 4170307 |
| studies on the dna of xenopus laevis oocytes. | | 1968 | 4172921 |
| immunological responses of the toad, xenopus laevis, to the antigens of the ciliate, tetrahymena pyriformis. | | 1968 | 4176105 |
| hypothalamic neurosecretion and metamorphosis in xenopus laevis. i. the effect of propylthiouracil. | | 1968 | 4179072 |
| [cytochemical study, using the electron microscopy, of rna and glycogen containing bodies in the oocyte cytoplasm of xenopus laevis]. | | 1969 | 4179637 |
| the production of two molecular classes of antibody in the toad, xenopus laevis, homologous with mammalian gamma-m (19s) and gamma-g (7s) immunoglobulins. | | 1969 | 4181573 |
| hypothalamic neurosecretion and metamorphosis in xenopus laevis. 3. the effect of an interruption of thyroid hormone synthesis. | | 1968 | 4183637 |
| [presence of dna in vitelline plaques of xenopus laevis oocytes]. | | 1969 | 4184324 |
| [presence of a low molecular weight rna in small oocytes of xenopus laevis]. | | 1969 | 4184346 |
| [measure of the template capacity of xenopus laevis egg ribonucleic acids during embryonic development]. | | 1969 | 4185585 |
| [effect of tetrodotoxin and tertaethylammonium chloride on the inside of the membrane of ranvier's node in xenopus laevis]. | | 1969 | 4188682 |
| hypothalamic neurosecretion and metamorphosis in xenopus laevis. iv. the effect of extirpation of the presumed trf cells and of a subsequent ptu treatment. | | 1969 | 4190327 |
| the mechanism of action of gonadotrophic hormones in amphibians: the stimulation of delta5-3beta-hydroxysteroid dehydrogenase activity in testes of xenopus laevis daudin. | | 1970 | 4195882 |
| [development of peroxidase activity and organification of iodide in the thyroid gland of xenopus laevis (daudin) during metamorphosis]. | | 1973 | 4196498 |
| serum immunoglobulin conten in normal and lymphoid tumor-bearing xenopus laevis. | | 1973 | 4198048 |
| effect of ethylenebis (dithiocarbamic acid)disodium salt(nabam)and ethylenebis(dithiocarbamato)manganese(maneb) on xenopus laevis development. | | 1973 | 4199117 |
| ontogeny and localization of the crystallins during embryonic lens development in xenopus laevis. | | 1973 | 4201078 |