bluuebunny/crossref_metadata_2025_split huggingface dataset:
Acid phosphatase activity in the development of the cement gland in Xenopus laevis
Authors: Ling Brenda Yu‐Feng , Lyerla Timothy A. 
Published: June 2005

AbstractThe properties of acid phosphatase from the cement gland of Xenopus laevis embryos were investigated both biochemically and electrophoretically. The studies were made on excised glands at a preregressing stage (stage 35/36, Nieuwkoop and Faber staging series) and a regressing stage (stage 45). The total activity (amount of p‐nitrophenol released/hr/gland) of acid phosphatase increased 1.7‐fold while the specific activity (amount of p‐nitrophenol released/hr/μg protein) increased 2.8‐fold from stage 35/36 to stage 45. There was some indication of a changing pH pattern during regression. Acid phosphatase activity showed a slight peak at pH 4.5 at stage 35/36 but a sharp optimal peak at pH 5.0 at stage 45. Also, there was increased phosphatase activity in both isotonic and hypotonic homogenates, in the absence of Triton X‐100, during gland cell regression. Electrophoretic separation of acid phosphatases from cement gland homogenates resolved two isozymes at stage 35/36, and two more forms appeared at stage 45. Both the quantitative and qualitative changes seen during cement gland development suggest a correlation between acid phosphatase activity and gland cell regression.
Influence of embryonic estrogens on adult feather coloration in the duck Anas platyrhynchos
Authors: Mueller Nancy S. 
Published: June 2005

AbstractEmbryos of the Rouen duck were treated on day 11 to 18 with a single injection of estradiol benzoate in the air chamber. After hatching, skin grafts were exchanged between male ducklings that had been treated with estrogen in ovo and control males. The results showed that the skin of male embryos can be permanently feminized to the same extent as untreated female embryos simply by exposing embryonic male skin to female sex hormones during embryogenesis.
Control of spawning in the tunicate Styela plicata by variations in a natural light regime
Authors: West Alan B. , Lambert Charles C. 
Published: June 2005

AbstractThe physical parameters controlling the release of gametes in Styela plicata were studied in laboratory experiments designed to simulate environmental conditions. Gravid animals left in constant light did not spawn until subjected to a minimum dark period followed by a sufficient amount of light. The maximum spawning success, determined by laboratory experiments, was found during the period between September, 1974 and March, 1975. The minimum dark adaption time, derived statistically from the spawning curve, was found to be 8 hours, 30 minutes. Increasing the dark adaption time resulted in decreasing the amount of light necessary to induce spawning. The total time for an entire spawning cycle (i.e., from the beginning of the dark adaption period to gamete release) was found to be approximately 24 hours. Field collection data supported the laboratory observations showing gamete release in the late afternoon, close to sunset. The amount of dark adaption affects the amount of light necessary to induce spawning suggesting a reversible photochemical reaction. Temperature limits for spawning in the laboratory were found to be 11–28°.
Differential cortical degradation in the two members of early conjugant pairs of Oxytricha fallax
Authors: Hammersmith Robert L. 
Published: June 2005

AbstractA differential resorption of the anterior ventral cortical structures is shown to occur in early conjugating pairs of Oxytricha. The member on the pair's left resorbs the collar membranelles and the frontal and right marginal cirri; the member on the pair's right resorbs the central and posterior membranelles (lapel) of the adoral zone of membranelles. The lapel of the left member then aligns with the collar of the right member to form a composite structure which appears with light and scanning electron microscopy to be completely integrated. Consequently, a 4–5‐hour‐old pair contains slightly more than one complete set of anterior ventral organelles (viz., one extra set of undulating membranes) and two complete sets of ventral and anal cirri.Analysis of conjugant pairs in which the two members are joined in abnormal positions suggests that neither the proximity of certain cortical organelles to the region of cytoplasmic bridge formation, the specific pairing position, nor the relocation of certain cortical organelles into a different cortical region is directly responsible for determining which resorption pattern occurs. Furthermore, analysis of the cortical events in conjugating doublets suggests that neither nuclear determination nor differential gene expression can account for the phenomena observed in Oxytricha.
Neurotrophic activity of brain extracts in forelimb regeneration of the urodele, Triturus
Authors: Singer Marcus , Maier C. E. , McNutt Walter S. 
Published: June 2005

AbstractThe loss in protein synthesis which the regenerating forelimb of the newt suffers after denervation can be recovered by infusing into it an extract of newt soluble brain protein. Moreover, the synthesis of basic protein shows a greater response to the active brain principle than does that of acidic protein. The active agent of the nervous tissue is destroyed by heat and trypsin digestion. Extracts of liver and spleen, similarly prepared, do not evoke recovery of lost protein synthesis. Synaptosomal extracts of the frog brain also cause recovery of protein synthesis in the denervated regenerate, demonstrating the likelihood that the active agent is not species‐specific within these amphibians, that it is a constituent of the neuronal fraction of nervous tissue, and that it is present in axonal terminals. Additional experiments showed that the nervous agent is likely a basic protein, and that the amount of protein infused is of the order of only 1.0% of the total regenerate protein. The significance of the findings is discussed in relation to the nature of the effect on protein synthesis and the nature of the active principle.
Genetic control of cell differentiation in platyfish‐swordtail melanomas
Authors: Vielkind Ursula 
Published: June 2005

AbstractIn certain fish hybrids, malignant transformation of pigment cells is due to the presence of a tumor gene (Tu), the action of which is controlled by several regulatory elements. Absence of these controlling genes causes rapid proliferation of the Tu‐transformed cells and ultimately results in melanoma formation. One of these genes has been identified as a differentiation gene (Diff), since it seems to control the differentiation of the transformed pigment cells. Light and electron microscopy of Tu‐transformed cells of fish differing in the dosage of Diff, and the determination of tyrosinase activity in homogenates of the respective tissues revealed that the degree of cellular differentiation depends on the dosage of Diff present in the genome. It is concluded that the gene Diff promotes the differentiation of malignant melanoma cells into benign melanophores.
The effect of thymectomy at different stages of larval development on the immune response of the clawed toad to sheep erythrocytes
Authors: Horton J. D. , Rimmer J. J. , Horton Trudy L. 
Published: June 2005

AbstractThe role of the thymus during the first three weeks of larval life in the maturation of humoral immunity in the amphibian, Xenopus laevis, is examined. Thymectomy throughout this period dramatically affects the heterologous red cell response of young adults. Sheep erythrocyte (SRBC) administration elicited haemolytic antibody production in the blood and in the spleen (measured by the appearance of plaque forming cells) of control animals, but failed to do so in all thymectomized toadlets. Moreover, use of the immunocytoadherence assay, which proved to be a sensitive test for SRBC reactivity in control Xenopus, indicated a complete absence of induced responsiveness to this antigen in the spleens of thymectomized toadlets, even in those animals thymectomized as late as 22 days of age.In contrast to allograft immunity in Xenopus, which is suppressed only by thymic ablation during the first two weeks of larval life, the development of reactivity to heterologous erythrocytes therefore requires an additional period of thymic influence during ontogeny. These experiments support a concept of thymus‐dependent cell heterogeneity in amphibians.
Stromal induction and specification of morphogenesis and cytodifferentiation of the epithelia of the mullerian ducts and urogenital sinus during development of the uterus and vagina in mice
Authors: Cunha Gerald R. 
Published: June 2005

AbstractHomotypic and heterotypic recombinations were prepared with trypsin‐separated epithelium and stroma from uterus of 1‐ to 9‐day‐old and vagina of 2‐ to 150‐day‐old mice. Growth of homotypic recombinants in adult female hosts resulted in normal uterine and vaginal morphogenesis. Heterotypic recombinants composed of uterine stroma and vaginal epithelium (VE) usually formed uterus, while recombinants composed of vaginal stroma and uterine epithelium (UE) usually underwent vaginal morphogenesis.The development response of these heterotypic recombinants was age‐dependent. Epithelia (UE and VE) from mice two to five‐days old were responsive to stromal induction. However, from days 5 to 9 postpartum a progressive loss in competence was observed in both epithelia, and vaginal epithelium nine or more days old was unresponsive to heterotypic inductores. Inductive activitves of uterine stroma were demonstrated in 2‐ to 7‐day‐old neonates and of vaginal stroma in 2‐ to 150‐day‐old mice. These results indicate that establishment of the regional specification of Mullerian and sinus epithelium during uterine and vaginal morphogenesis is due to inductive activities of the stroma.
Composition of bladder urine of the coelacanth, Latimeria chalumnae
Authors: Griffith Robert W. , Umminger Bruce L. , Grant Blake F. , Pang Peter K. T. , Goldstein Leon , Pickford Grace E. 
Published: June 2005

AbstractMajor inorganic electrolytes and organic solutes were measured in urine obtained from the bladder of a live specimen of the coelacanth, Latimeria chalumnae, and the results were compared with data on blood serum from the same fish. Osmolarity is essentially identical in the two fluids. Magnesium, phosphate, sulfate, creatine, creatinine and glucuronate are highly concentrated in the urine whereas chloride, bicarbonate, protein and glucose are much lower in urine than in serum. There are moderately higher levels of potassium, total amino acids and total carbohydrates and somewhat lower concentrations of sodium, trimethylamine oxide and lactate in urine than in serum. Total calcium levels in urine are considerably lower than serum total calcium, but are slightly higher than the dialyzable calcium fraction of serum. Urea levels in urine and serum are identical.
The oral apparatus ofTetrahymena pyriformis, Strain WH‐6. II. Cytochalasin B inhibition of oral apparatus morphogenesis
Authors: Gavin R. H. 
Published: June 2005

AbstractThe effects of cytochalasin B on oral apparatus morphogenesis and cell division were studied in synchronizedTetrahymena pyriformis, strain WH‐6, syngen 1. Cytochalasin B brought about the rapid arrest of oral apparatus primordium development when added prior to the completion of oral apparatus membranelle differentiation. Cells arrested in development did not divide. When cytochalasin B was added after this transition point, oral apparatus morphogenesis and cell division were completed. The effects of cytochalasin B could be reversed by washing it from the medium. Even though cytochalasin B (at 400 μg/ml) reduced protein synthesis by 30%, the data are consistent with the interpretation that cytochalasin B prevents an assembly process during the membranelle differentiation phase of oral apparatus development.
Fertilization acid of sea urchin eggs is not a consequence of cortical granule exocytosis
Authors: Paul Miles , Johnson James D. , Epel David 
Published: June 2005

AbstractSea urchin eggs treated with 10 mM NH4Cl release a “fertilization acid” although cortical granule exocytosis does not take place. If the eggs are inseminated following ammonia activation, the cortical reaction occurs and a fertilization membrane elevates in the absence of detectable acid release. Examination by electron microscopy of eggs fixed between ammonia activation and insemination confirms the presence of intact granules. Thus, the fertilization acid is not caused by the release of the cortical granules. Ammonia treatment of fertilized eggs stimulates further release of acid. The release of acid can occur repeatedly in ammonia activated eggs if they are washed into normal seawater between successive ammonia treatments. Our results suggest that the release of fertilization acid is related to some metabolic process which can be turned “on or off”.
In vitro utilization of exogenous procollagen by embryonic tooth germs
Authors: Galbraith Donald B. , Kollar Edward J. 
Published: June 2005

AbstractEmbryonic mouse tooth germs treated with L‐azetidine‐2‐carboxylic acid cease their development, undergo a regression of the enamel organ, and do not maintain the histological characteristics of the explanted dental organ. On the other hand if procollagen is added exogenously to explants continuously treated with Lazetidine, the effects of the inhibitor are not seen and the tissue is maintained. Thus, exogenously supplied procollagen supports morphogesis in tooth rudiments that are unable to synthesize procollagen.
Stability of RNA synthesized by the mouse oocyte during its major growth phase
Authors: Jahn Carolyn L. , Baran Madelyn M. , Bachvarova Rosemary 
Published: June 2005

AbstractThe RNA of growing mouse oocytes and ovulated ova was labeled by injection of a solution containing tritiated uridine into the ovarian bursa. The time course of incorporation into RNA by oocytes was followed by analysis of alkali‐labile acid insoluble radioactivity and by autoradiography. The results show that most of the incorporation into RNA by growing oocytes takes place within one day of bursal injection of the precursor, reflecting the rapid fall of label in the acid soluble precursor pool. The RNA of growing oocytes of all sizes is unusually stable, at least 80% of the labeled RNA present two days after bursal injection being retained until ovulation 10 to 20 days later. The fraction of heterogeneous RNA in labeled RNA of ova was estimated as 20% by sucrose gradient analysis. It is likely that egg RNA is synthesized primarily during the period of oocyte growth one to three weeks before ovulation.
Cell migration kinetics in the stomach of Styela clava (Urochordata: Ascidiacea)
Authors: Ermak Thomas H. 
Published: June 2005

AbstractBy autoradiography with tritiated thymidine, the rate of cell migration was studied for the groove population of epithelial cells lining the stomach of Styela. After one hour, the tritiated thymidine is incorporated into undifferentiated, dividing cells. Labeled differentiated cells appear after three days, and the migration of labeled cells to the extrusion zone takes about 16 days (T= 19°C). Stomach growth is accomplished by an increase in both number and height of epithelial folds. The percentage rate of cell migration probably remains fairly constant throughout adult life. However, it is decreased by starvation and low temperatures.
A reversible, hydrogen lon blockade of spontaneous oocyte maturation in the starfish: Locus of action
Authors: Cloud J. G. , Schuetz A. W. 
Published: June 2005

AbstractStarfish (Asterias forbesi) oocytes encased within their follicle cells mature spontaneusly during a portion of the normal reproductive period when released from the ovary into seawater. A previous report has shown that oocytes isolated in acidic seawater do not mature spontaneously but retain the capacity to do so when returned to normal seawater. The object of this study was to determine the mechanism by which acidic pH reversibly blocks spontaneous oocyte maturation in isolated follicles. Incidence of spontaneous oocyte maturation in follicles isolated in acidic seawater decreased as pH decreased from 7 to 4. Oocytes in which spontaneous maturation was inhibited (ASW at pH 4.7 to 5.4) underwent germinal vesicle breakdown with the addition of 1‐methyladenine. Oocytes isolated in acidic seawater (pH 4 or 5) with intact follicle cells matured spontaneously when transferred immediately to normal seawater (pH 8); after four hours, 60‐65% of the follicles incubated in seawater at pH 5 matured spontaneously when returned to normal seawater as compared to less than 10% of the follicles maintained at pH 4. Inhibition of spontaneous maturation was not reversible in the absence of the follicle cells. Oocytes isolated in acidic seawater with their follicle cells did not spontaneously mature when transferred to calcium‐free seawater at pH 8. The results obtained support the hypothesis that acidic seawater reversibly inhibits spontaneous oocyte maturation by interfering with the release of meiosis‐inducing substance from the follicle cells.
Anesthesia as an effective agent against the production of congenital anomalies in mouse fetuses exposed to electromagnetic radiation
Authors: Rugh Roberts , McManaway Mary 
Published: June 2005

AbstractA total of 130 female mice pregnant at 8 days were exposed singly to a 7.3 watt microwave waveguide at 2,450 MHz wave length while being monitored for total absorbed dose, the exposure being four minutes. Among the 1,328 offspring examined (327 of which were controls) those not anesthetized but irradiated showed greater fetal damage than those that were anesthetized and placed in one of the three positions with respect to the radiation beam. Immobilization with anesthesia and restraint in the broadside position provided the greatest protection to the fetus against any teratologic effects. Anesthesia reduces the body temperature to a degree equivalent to the rise in temperature expected from the radiation conditions used, hence the protection against the primary thermal effect of microwave irradiation.
Production of retarded, albino, regenerates in newts by alpha‐methyl‐p‐tyrosine
Authors: Taban C. H. , Cathieni M. , Constantinidis J. 
Published: June 2005

AbstractInhibition of tyrosine hydroxylase with alpha‐methyl‐p‐tyrosien retarded growth and prevented melanization of limb regenerate in adult newts (Triturus cristatus).
Body temperature of the lizard (Anolis carolinensis): Effect of parietalectomy
Authors: Roth Jan J. , Ralph Charles L. 
Published: June 2005

AbstractThermal behavior of parietalectomized, sham‐parietalectomized or intact lizards (Anolis carolinensis) was recorded in a test chamber containing moving photothermal gradients. Following parietalectomy, animals chose significantly higher temperatures than sham‐parietalectomized or intact control animals, which chose lower and statistically identical temperatures. When pre‐surgical and post‐surgical means are compared within groups, the eccritic temperature was 2.10°C higher following parietalectomy, 0.72°C higher following sham‐parietalectomy, and 0.31°C higher in intact controls during the postoperative measurements. The effects of parietalectomy indicate that the parietalpineal complex may be involved in behavioral thermoregulation by precisely regulating exposure to heat sources (e.g., sunlight).
Parietalectomy and thermal selection in the lizard Sceloporus magister
Authors: Engbretson Gustav A. , Hutchison Victor H. 
Published: June 2005

AbstractLizards were acclimatized to various regimes of temperature (15°, 35°C) and photoperiod (LD 08:16, 16:8). Parietalectomized, sham operated, and control animals were placed in thermal gradients and their body temperatures monitored for periods of up to 15 days. Daily rhythms of thermal selection were evident with higher temperatures selected in late photophase and lower temperatures selected in scotophase. Thermal selection was more variable in scotophase than in photophase. Parietalectomized lizards chose significantly higher body temperatures than did shams or controls. Acclimatization to temperature and photoperiod had little or no effect on the thermal preferendum. The preferred body temperature of controls was 33.2°C ± 3.59. Length of time in the gradient tended to change thermal preference, especially in lizards acclimated to 15°C. Through interactions with the pineal gland the parietal eye is probably important in synchronizing many bodily functions with photoperiod.
Phospholipase activity of sea urchin sperm: Its possible involvement in membrane fusion
Authors: Conway A. F. , Metz C. B. 
Published: June 2005

AbstractPhospholipase activity of egg‐water treated Arbacia punctulata and Lytechinus variegatus sperm was shown to result from the sequential action of phospholipase A and lysophospholipase. A transient burst of phospholipase A activity followed induction of the acrosome reaction with egg water. The time of appearance suggested an acrosomal localization of the enzyme. The peak activity of phospholipase A correlated with initiation of sperm‐egg fusion, suggesting a role for sea urchin sperm phospholipase A in membrane fusion and/or egg activation during fertilization.
Muscle satellite cells in urodele amphibians: Facilitated identification of satellite cells using ruthenium red staining
Authors: Popiela Heinz 
Published: June 2005

AbstractThe ruthenium red (RR) stained forelimb musculature of three species of urodeles Triturus (Notophthalmus) viridescens, Amblystoma maculatum, Amblystoma opacum in various stages of growth were examined with the electron microscope for the presence of satellite cells. It was found that RR staining facilitated greatly the identification of satellite cells. In young larvae of all three species satellite cells were detected with a frequency of 29% to 48% per total number of nuclei. In adult Triturus and Amblystoma maculatum satellite cells were no longer detected; instead “pericytes” as described by Hay ('74) were seen with a frequency of 12% and 3% respectively. During metamorphosis of Triturus satellite cells, with part of their myofiber‐satellite cell intercellular space filled with basement membrane material, occurred at a peak frequency. The cells presumably are intermediate in the formation of “pericytes.” At ten days after metamorphosis satellite cells and intermediate cells were no longer detected and the limb musculature contained only “pericytes” similar to the ones observed in adult newts. The significance of the presence of satellite cells in relation to limb regeneration and muscle regeneration is discussed.
The effect of growth and joint formation on bristle pattern in D. melanogaster
Authors: Tokunaga Chiyoko , Gerhart John C. 
Published: June 2005

AbstractDependence of bristle pattern on size and joint formation was studied for male first leg tarsi of fj (four jointed) and d (dachs) mutants in homozygotes and in mosaics resulting from X‐ray induced mitotic recombination. Homozygotes have four tarsal segments, lacking a third tarsal joint in most cases. The two proximal segments are shortened, the first by one‐third, and altered in bristle pattern, whereas the distal two segments are little affected. Expressivity of fj is high, and of d is low, for the extent and frequency of joint failure. The longer the second segment, the more complete the third joint and the greater the bristle number. Only the jointed side of the segment approximates two segments in its bristle pattern. Mosaic studies show that joint failure occurs autonomously in fj, or in the majority of d clones, and that joint formation by heterozygous clones is autonomous except in the border area contacting a fj or d spot lacking a joint, in which area joint failure occurs. Bristle pattern in this jointless heterozygous area switches to that of a single segment. Localized nonautonomy also occurs in the t‐rows of heterozygous tissue contacting a fj or d spot. Both mutant genes are interpreted as reducing longitudinal growth of the proximal tarsi, with joint failure as a consequence, and with alterations of bristle pattern resulting directly from size reduction, or indirectly through joint failure.