bluuebunny/crossref_metadata_2025_split huggingface dataset:
Electrophoretic studies of cholinesterases in brain and muscle of the developing chicken
Authors: Maynard Edith A. 
Published: June 2005

AbstractAcrylamide gel electrophoresis of aqueous homogenates from whole brain of perfused chick embryos of 18 days' incubation results in three anodally migrating zones having the properties of cholinesterases (ChE's 1, 2 and 3). These sites hydrolyze acetylthiocholine, alpha‐naphthyl acetate and alpha‐naphthyl propionate. Their activity is inhibited by 10−5 M eserine sulfate, by 10−4 M di‐isopropylfluoro‐phosphate, and by a 10−4 M solution of Burroughs‐Wellcome compound 284c51j dibromide. Homogenization with 0.1% Triton X‐100 selectively increases activity of ChE's 1 and 3, especially the former.The three ChE zones occur in all sub‐regions of brain which were examined: optic tectum, medulla, cerebellum, telencephalon, and optic nerve, although activities in the last area are very low. In homogenates of adult brain, ChE 1 (the most rapidly migrating form) is considerably less active, relative to ChE's 2 and 3, than in embryos of 18 days' incubation.Aqueous homogenates of heads of embryos at stages 17–18 (3rd day of incubation) show a weak ChE 2. Inclusion of Triton X‐100 in the homogenate results in appearance of all three ChE zones in this tissue.Electrophoresis of blood plasma from embryos of 18 days' incubation produces two zones of activity comparable in mobility and substrate affinity to ChE's 2 and 3 of brain. The relative intensities of the reactions in electrophoretic preparations of the two tissues plus the results from perfused brains indicate that residual blood is not the source for the brain enzymes.Electrophoresis of homogenates of skeletal muscle from embryos of 18 days' incubation produces three zones of ChE activity similar to those of brain. In adult muscle, the ChE's 2 and 3 are present, although less intense, and ChE 1 is not detectable. Electrophoretic preparations of limbs from embryos of stages 20–22 show the fastest migrating ChE (ChE 1) as the predominant form. All three ChE's are detectable in limbs at stages 26–27.The results are discussed in relation to literature in the fields of manometric and microscopic studies of cholinesterases in the developing chicken.
Studies in aging. II. The effects of injecting hemolymph from younger and older donors on the fecundity and the adult life span of hosts in drosophila
Authors: Sondhi K. C. 
Published: June 2005

AbstractAttempts were made to study the effects on Swedish inbred Drosophila melanogaster females of replacing equivalent volumes of hemolymph from younger and older donors of the same strain. The physiological effects on hosts were studied by examining the fecundity and the adult life span.Nine to ten‐day‐old hosts, receiving 0.25 μl of hemolymph from 3‐4‐day‐old donors, do not differ appreciably either in fecundity or longevity from the controls. Similarly, 12–13‐day‐old hosts, undergoing replacements of 0.25 μl and 0.50 μl of hemolymph from freshly emerged donors, fail to show an improvement in the egg production or in the life span. It is suggested that the hemolymph donated by younger females lacks the properties that are associated with a higher fecundity or a higher expectation of life.Freshly emerged hosts, in which 0.25 μl of hemolymph from 12–13, 16–17 and 23–24‐day‐old hosts was replaced, undergo a remarkable life‐shortening without a decrease in the egg production. In individuals, deprived of 0.25 μl of hemolymph, similar results are obtained; that is, only reduction in the life span is realized, the fecundity being unaffected.The reduction in the life span of hosts injected with the hemolymph from older females is explained as due to the presence of deleterious factors in the hemolymph of older individuals. Such factors are considered in terms of “accumulation and depletion phenomena” commonly observed in insects. The absence of reduced egg production in females under stress is interpreted as due to homeostatic mechanisms which tend to insure the period of active reproduction. The bearing of these results on the evolution of life span in organisms is discussed.
Gene activities in the Malphigian tubules of Drosophila hydei at different developmental stages
Authors: Berendes H. D. 
Published: June 2005

AbstractA detailed analysis of the puffing patterns of Malphigian tubules, stomach and salivary glands of Drosophila hydei revealed that from a total of 110 easily recognizable puffs 76 (69%) are present in all tissues at one time or another during mid and late third instar. A small number of puffs showed tissue specific activity. Three such puffs were restricted to the Malphigian tubules, four to the stomach and seven to the salivary glands. A number of puffs was found to be absent in only one of the investigated tissues during the whole of the period. A comparison of the puffs specific for a definite developmental stage revealed that from the 22 puffs in the salivary glands which were specific for the period of puparium formation, only six showed an identical reaction in all tissues. In the late third instar stage three puffs were observed to become active earlier in the stomach than in the salivary glands, whereas no activity of these puffs was found in the Malphigian tubules. A possible relation of these puffs to the process of histolysis is discussed.A comparison of the puffing patterns of Malphigian tubules in larvae and in adults showed that 12 puffs which were observed in the larvae were absent in the adults. No specific puffs occurred in the adult Malphigian tubules.
The fate of amphibian regenerating blastema implanted into lentectomized eyes
Authors: Stone L. S. 
Published: June 2005

AbstractTail blastemas of larval anurans and urodeles were implanted into 106 lentectomized larval eyes to test claims that lenses develop from blastemas in an eye environment. None of these eyes regenerate a lens from the dorsal iris. Lentectomy was complete in all 35 Amblystoma tigrinum, in 34 of 36 Rana pipiens and 21 of 35 Rana clamitans eyes.After complete lentectomy, blastema grafts formed spherical masses of mesenchyme cells sometimes enclosed in epithelial vesicles, but never associated with lens fibers. Lens fragments not removed were easily identified. They were usually fused with the blastema. Their appearance was the same from one to many days after implantation.Leg and tail blastemas were implanted into 64 completely lentectomized adult Triturus viridescens eyes which regenerate a lens from the dorsal iris. The grafts formed spherical compact groups of epithelial and mesenchyme cells, loose cultures of cells and fibers, or cartilage and muscle, but never lens fibers. One of 13 brain segments implanted into lentectomized newt eyes carried dorsal iris cells on its surface. They formed a small lens gving a false picture of blastema origin.From an analysis of the literature and of the results of these experiments it is concluded that the claims so far made for lens formation from blastema cells are an incorrect interpretation of a mere fusion of lens fragments and implanted tissues and that regenerating tissues of anurans and urodeles are not competent to form lens as has been claimed.
Ionic requirement for epinephrine stimulation of frog skin gland secretion
Authors: Seldin Jonathan P. , Hoshiko T. 
Published: June 2005

AbstractThe outer surface of isolated frog (R. pipiens) skin was observed through a dissection microscope during addition of epinephrine (2 × 10−6 w/v) to the inside bathing solution. Small droplets formed at pore openings within 30 seconds; the process appeared to be complete within 1 to 2 minutes. After washing out the bathing solution and a 30 minute recovery period, the response could be repeated up to six times. The gland requires NaCl for multiple responses. Neither added Ca nor added K is required. Cs and K may replace Na but only to a minor extent. Mg, Rb and Li could not substitute for Na. Chloride is the preferred anion, and while NO3 may be a partially effective substitute, I and SO4 were not.
Analysis of trypan blue‐induced rumplessness in chick embryos
Authors: Kaplan Stanley , Grabowski Casimer T. 
Published: June 2005

AbstractTreatment of chick embryos early in development with the teratogen, trypan blue, results in a high incidence of rumplessness at later developmental stages. Experiments were conducted to discover the causative events between dye administration and rumplessness. Initially, 167 two‐day embryos were treated by injection of 0.02 ml 0.1% trypan blue (in saline) into the yolk sac. Controls (42) were injected with 0.02 ml of 0.85% NaCl. Dye‐treated embryos examined at three days exhibited a high incidence of hematomas caudal to the leg buds. All embryos examined on or after five days were rumpless. Many embryos examined at four days exhibited an apparently intermediate condition in the development of this defect — a caudal hematoma coupled with beginning degeneration of tail tissues. Histological analysis of these embryos and additional 60 examined and preserved at several intervals (12, 16, 20 and 24 hours) after dye administration suggested the following sequence of events: (1) swelling of the dorsal aortae, (2) bursting of these vessels in the rump, (3) hematoma formation by extravasation from the burst vessels, (4) destruction, by the hematoma, of surrounding rump tissues, (5) resorption of dead or dying tissues, (6) rumplessness. Studies of another series of embryos, each of which was studied in ovo for several days during development, confirmed the destructive effect of a hematoma on morphogenesis of the rump. Dye treated embryos which did not form a caudal hematoma went on to develop a normal rump. Conversely, each embryo which exhibited a caudal hematoma early in development eventually became rumpless.
The influence of different brain regions on periodic motility of the chick embryo
Authors: Decker John D. , Hamburger Viktor 
Published: June 2005

AbstractPrevious investigations have shown that the motility of the normal chick embryo was spontaneous and periodic. Activity increased from 40% of a 15‐minute observation period at day 9 to more than 80% on day 13. Experimental embryos with cervical spinal gaps showed mean activity levels about 10–20% below normal embryos. The following experiments were designed to analyze this difference, which was attributed to the brain.Operations performed on 1 1/2‐day‐old embryos consisted of: (a.) Extripations of the mesencephalon. (b.) Extripations of the mesencephalon plus the metencephalon. Durations of activity and inactivity phases were recorded between 8 and 18 days of incubation and the mean per cent of time spent in activity during standard observation periods was calculated and plotted graphically. Gross effects of these ablations on the morphology were noted and their extents histologically determined. Data were analyzed statistically and compared with those of normal and spinal embryos.Embryos with a gap anterior to the medulla showed an influence from this region of the brain on days 9 and 17. The cerebellum showed a contribution to motility following day 13. Brain parts rostral to the cerebellum influenced embryonic motility on days 11 through 15. This does not preclude that these brain regions were inactive at other stages where their influence may have been too slight to be detected, or masked or inhibited by stimulation from other regions of the brain.
Deoxynucleoside and deoxynucleotide metabolism during diapause and adult development of the Cecropia silkmoth
Authors: Berry S. J. , Firshein W. 
Published: June 2005

AbstractThe activities of deoxynucleoside kinases and the corresponding monophosphate kinases were examined during pupal diapause, after injury to the diapausing pupa, and during adult development of the Cecropia silkmoth. Homogenates of various tissues showed the loss of a number of these enzymatic capacities during diapause, and the reaquisition of the activity of many of the monophosphate kinases during adult development and after injury. The kinases responsible for the phosphorylation of deoxycytidine and deoxyguanosine were never detected in any tissues examined even in the later stages of adult development. Deoxycytidine deaminase activity was detected, and its activity was stimulated by the onset of adult development. The product of this deaminase activity was identified chromatographically as deoxyuridine, and mechanisms are proposed for the conversion of deoxyuridine to thymidine or thymidine monophosphate. It is also postulated that dCMP and dGMP arise, not from the direct phosphorylation of the deoxynucleosides but from reduction of the corresponding ribotides.
Influence of optic cup on chick embryonic lens in vitro
Authors: Wolpow Edward R. 
Published: June 2005

AbstractChick embryonic lens, either dissected clean, or with a collar of optic cup left attached, was studied in defined medium in tissue culture. In the case of 6‐day lenses without collars in tissue culture, the last cells to degenerate are found in a band at the equator. If a collar of optic cup remains attached, a band of cells at the equator is again last to degenerate but does so significantly later than if collar is not present. When lenses with only the preserved band of equatorial cells are transplanted to lentectomized embryo eyes, complete new lenses are regenerated. The experiments are taken to indicate that, at least in vitro, physiologically important substances can be presumed to pass from optic cup to lens.
Immunological studies of protein synthesis during sea urchin development
Authors: Westin Monica , Perlmann Hedvig , Perlmann Peter 
Published: June 2005

AbstractEggs and developmental stages of the sea urchin Paracentrotus lividus were incubated with radioactive (14C) amino acids. Incorporation of label into antigen during different phases of development was studied by means of rabbit antisera against sea urchin material.Approximately 50% of the label present in the proteins, extractable from unfertilized eggs and older stages, was bound to antigens which were precipitated with the antisera at hand. The concentration of this antigen bound radioactivity in the extracts increased strongly from unfertilized egg, where it was small, up to 48 hours of development (pluteus stage). The figures reflected an increase of specific radioactivity of the antigens precipitated. In unfertilized eggs, less than 10% of the antigen bound label was incorporated into “egg specific” antigens, while the rest consisted of antigens common for eggs and older stages. In contrast, in plutei, almost 50% of the label was in “new” antigens not present in unfertilized eggs.As shown by agar diffusion techniques and autoradiography, extracts of unfertilized eggs contained at least three labeled antigens. One of these disappeared completely already before hatching while another was present throughout development but was unlabeled in older stages. A third antigen showed a transient period of more intense labeling during the cleavage stages but also disappeared after gastrulation. Other antigens which were unlabeled in the unfertilized eggs became radioactive soon after fertilization. The most striking changes in labeling pattern started at hatching (12 hours) and later when the blastulae develop into differentiated gastrulae and plutei. In the plutei, label was found in at least three antigens not detectable in eggs and early stages.The results suggest that protein synthesis before and after hatching comprises antigenically different proteins and thus seems to be governed by different types of messenger RNA available during the varius developmental phases.
History of the hypoblast in Salmo
Authors: Ballard William W. 
Published: June 2005

AbstractSpots printed on the blastodisc of Salmo gairdneri with Nile blue sulfate prior to and during the formation of the germ ring and embryonic shield show during the morphogenetic movements that not many of the germ ring cells are derived from the center of the blastodisc. Evidence suggests that only a few of the loose round cells of the deep part of the ring and of the axial nubbin are produced by local dropout of cells at the margin of the blastodisc, but that most of them arrive there by outward migration from the outer two‐thirds of the disc. The embryonic shield is produced by a convergence of internal cells that starts early in the fifth day at 10° C, augmented by a massive descent of consolidated internal cells from the central one‐third of the blastodisc which then form the forebrain and optic vesicles. The cellular envelope is not involved in an invagination, nor does it take part in the general convergence movements.Chalk grains incorporated into the lower surface of the germ ring and the embryonic shield reveal the destination of the cells which carry them along. The hypoblast of the ring continues to converge toward the shield until the closure of the yolk plug on the ninth day. The epiblast of the ring meanwhile forms the cell layers of the yolk sac. Head mesoderm, pharynx endoderm and notochord materials are assembled directly into the embryonic shield while the germ ring is forming. Additional evidence is presented that these parts are not formed by invagination. Materials of the hypoblast originally placed as far as 90° out on the ring from the early shield reach the trunk endoderm, and materials from the hypoblast of the entire ring are passed along toward and into the somite and lateral plate strips. Their oblique paths of migration, combining both epiboly and convergence, are at marked angles to the simple epibolic paths of the epiblast cells, and it is suggested that the split between epiblast and hypoblast in the germ ring is a result of this shearing effect.
Studies on the terminal respiratory system in the minute(2)z mutant of Drosophila melanogaster
Authors: Goldin Herbert H. 
Published: June 2005

AbstractIndividual sites of ATP synthesis were studied in the Minute(2)z mutant of Drosophila melanogaster by supplying appropriate substrates to isolated mitochondria and determining the ratio of phosphorus esterifield to oxygen consumed at each locus. In this manner it was determined that the terminal locus of phosphorylation in the Minute is comparable to control, but the first two sites of ATP synthesis and possibly the substrate level phosphorylation are aberrant.The significance of these data and their relation to the Minute effect are discussed.
Growth in Hydra viridis
Authors: Shostak Stanley 
Published: June 2005

AbstractThe dimensions of an epithelium such as gastrodermis of Hydra viridis may be governed by several different cellular activities. Changes in the total cell number of this epithelium and in the movements of markers placed within it by grafting show what roles cell division and cell loss play in determining the epithelium's length.A hydra's rate of lengthening is ten fold greater during its development as a bud than after it has detached from its parent. Changes in the rates of movement of gastrodermal cells onto developing buds, and of sloughing at tentacles or foot are, however, not correlated with this change in the rate of lengthening. Buds do not begin forming until at least two days after the rate of lengthening in the parent decreases. The rate at which the bud's gastrodermal cells move out onto developing tentacles is as great as the sum of the rates of movement of parental gastrodermal cells onto mature tentacles and toward the foot.The time at which the rate of lengthening of the animal changes is also not correlated with changes in the rate of growth of the gastrodermis. The combined rate at which a bud's gastrodermis accumulates cells from the parent's gastrodermis and grows within itself (intrinsic growth), is the same as the rate of gastrodermal growth in freshly detached animals which is entirely intrinsic. Furthermore, these rates are the same as that of the gastrodermis of budding parents, if the amount of growth replacing cells moving onto developing buds (cryptic growth) is added to the amount providing additional cells to the parent's gastrodermis. It seems that the gastrodermis of Hydra consists of four separate self‐generating cell populations: The populations at the ends support the tentacles or foot. Between these are two more which meet at the lower edge of the budding region and support the development of buds. These more central populations can expand when the animal lengthens.
Acetylcholinesterases and non‐specific esterases in developing avian tissues: Distribution and molecular weights of esterases in normal and dystrophic embryos and chicks
Authors: Wilson Barry W. , Mettler Marilyn A. , Asmundson Roderick V. 
Published: June 2005

AbstractThe acetylcholinesterases and non‐specific esterases of embryo and chick muscle, brain, heart and other tissues were investigated using acrylamide disc gel electrophoresis and spectrophotometric enzyme assays. Migration of the proteins as a function of acrylamide gel concentration was used to determine their molecular weights and relative charges. Acetylcholinesterase isozymes in embryonic skeletal muscle and brain differed in size but not appreciably in charge. Their molecular weights were approximately 420,000, 300,000 and 220,000. The non‐specific esterases of all the tissues studied differed only by charge from each other; their molecular weight averaged 160,000.Previous experiments indicated that white‐fibered muscles from birds selected for muscular dystrophy exhibited acetylcholinesterase isozymes similar to those in embryonic muscle while normal muscles did not. The studies reported here show that the acetylcholinesterases of normal embryo muscle and dystrophic chick muscle migrated similarly on acrylamide gels and responded similarly to anticholinesterase agents. The acetylcholinesterase activity of muscles from chicks of normal females X dystrophic males resembled that of normal chicks. The results are consistent with the hypothesis that white‐fibered muscles of birds inbred for muscular dystrophy are unable to repress the synthesis of isozymes of acetylcholinesterase characteristic of normal embryo skeletal muscle.
An experimental study of sexual dichromatism in the duck Anas platyrhynchos
Authors: Mueller Nancy S. 
Published: June 2005

AbstractSkin grafts were exchanged between Rouen Ducks to determine the influence of sex genotype and the modifications induced by the hormonal environment on the coloration of feathers. The skin of both sexes responded similarly to hormones of the female, but male plumages, both breeding and “eclipse,” were produced only when both skin genotype and endocrine environment were male. Female skin grafted on males produced feathers that were “feminized.” The results show that sex differences in the skin are present at hatching and maintained through succesive generations of feathers.