bluuebunny/crossref_metadata_2025 huggingface dataset:
CASK localizes to nuclei in developing skeletal muscle and motor neuron culture models and is agrin‐independent
Authors: Gardner Katherine L. , Sanford Jamie L. , Mays Tessily A. , Rafael‐Fortney Jill A.
Published: June 2005

Membrane‐associated guanylate kinases (MAGUKs) are cytoplasmic multi‐domain proteins that serve as scaffold proteins at cell junctions and synapses. Calmodulin‐associated serine/threonine kinase (CASK) stabilizes the integrity of synapses in the brain. Additionally, CASK is capable of acting as a transcriptional co‐activator and localizes to neuronal nuclei in the developing brain. We have recently described CASK localization to both the pre‐ and post‐synaptic membranes of the neuromuscular junction (NMJ), where it forms a complex with discs large (Dlg). CASK also localizes to some, but not all nuclei in adult mouse skeletal muscle. To begin to dissect the roles of CASK in the cellular components of the NMJ, we investigated the localization of CASK during differentiation in cell culture models of skeletal muscle and motor neurons. We demonstrate that CASK localizes to the nucleus in undifferentiated myoblasts, but is pre‐dominantly in the cytoplasm in differentiated myotubes of the C2C12 myogenic cell line. We also show nuclear localization of both CASK and Dlg in a motor neuron‐neuroblastoma hybrid cell line, MN‐1, suggesting a role for CASK and Dlg in nuclei of neurons in the peripheral nervous system. Finally, we demonstrate that CASK and Dlg do not co‐cluster with acetylcholine receptors in C2C12 myotubes in response to agrin or laminin treatment, suggesting a novel mechanism of recruitment to the NMJ that is independent of acetylcholine receptor and utrophin complexes. These studies delineate important developmental characteristics of CASK and Dlg, and suggest dual roles for these proteins in both the skeletal muscle and motor neuron components of the NMJ. © 2005 Wiley‐Liss, Inc.
Nucleic acids and protein synthesis of isolated cells from chick embryonic spinal ganglia in culture
Authors: Utakoji Tadashi , Hsu T. C.
Published: June 2005

Dissociated monolayer cell cultures of chick embryonic spinal ganglia were set up on collagen‐coated coverslips and incubated in 5% CO2 atmosphere at 38°C. Neurons were maintained in good condition for approximately three weeks and showed regeneration of nerve fibers as well as recovery from chromatolysis to normal Nissl pattern.

Synthesis and transport of nucleic acids and protein in neurons and in spindle cells were studied with tritiated precursors by means of autoradiography.

Less than 3% (10 of 318) of nerve cells from 12‐day‐old chick embryo spinal ganglia showed tritiated thymidine incorporation, whereas 27% (511 of 1880) of spindle cells from the same source incorporated tritiated thymidine. Thus, under our cultural conditions most neurons did not synthesize DNA.

Both neurons and spindle cells incorporated tritiated uridine. Newly synthesized RNA appeared in the nucleus, and after several hours it was distributed over the perikaryon of neurons and the cytoplasm of spindle cells. The label was never found in nerve fibers, even after prolonged tritiated uridine treatment. A conclusion is thus made that RNA is absent in the nerve fibers.

In neurons, protein was synthesized only in the perikaryon. Nerve fibers did not show protein synthesis. Newly synthesized protein was transported from perikaryon distally along nerve fibers at a rate of approximately 10 mm per day.
Thermal stress and anomalous development of mosquitoes (Diptera: Culicidae). V. Effect of temperature on embryogeny of aedes stimulans
Authors: Anderson John F. , Horsfall William R.
Published: June 2005

Primordia of organs of the male reproductive system develop abnormally in response to near lethal temperatures when thermal pressure is applied at a time of cellular differentiation during embryogeny and postembryogeny. This paper is concerned primarily with the thermally induced imaginal deformities effected during embryogeny. All parts of the masculine system may be affected except the gonads. Part or all of the tract and accessory glands may be deleted by regulating the time and duration of exposure to critical temperatures. The critical period for the inhibition of development of the reproductive tract in the embryo occurs primarily during the fourth and fifth days of ontogeny. Morphogenesis of imaginal female organs was unaffected by excessive embryogenic temperatures in either genetic females or genetic males. Certain primordia of larval parts developed abnormally when embryos were subjected to temperatures somewhat above those permitting survival beyond the first larval instar.
The role of interstitial cells in the maintenance of hydra. III. Regeneration of hypostome and tentacles
Authors: Diehl Fred A. , Burnett Allison L.
Published: June 2005

Animals whose interstitial cells have been destroyed by nitrogen mustard are able to regenerate tentacles and hypostome five times over a period of 25 days. After successive regenerations, animals lack cnidoblast cells and the regenerated tentacles are completely devoid of nematocysts. It is concluded that although interstitial cells are necessary for the continued life of the Hydra they are not necessary for the initiation of regenerative events nor for the maintenance of any stage in the regeneration sequence.
Studies on the physiology and genetics of the rotifer, Asplanchna. II. The genic basis of a case of male sterility
Authors: Birky C. W.
Published: June 2005

Two mutant clones have been obtained by selfing from closely‐related clones of the rotifer, Asplanchna brightwelli. The females of these male‐sterile clones are fertile but the males are unable to fertilize females of the mutant or of normal clones. Females from the mutant clones were out‐crossed to fertile males of a wildtype clone and F2, F3, and test‐cross generations were obtained. The results of these crosses indicate that the male‐sterile phenotype in both mutant clones is determined by a recessive mutation designated “male‐sterile” (ms). The mutant ms allele also appears to act as a detrimental, for the viability of zygotes (resting eggs) which are heterozygous for this gene is greater than that of homozygous recessives. This gene shows a maternal effects, for the phenotype of the haploid (or homozygous) males is determined by the genotype of their mothers. Test‐crosses of seven individual males born to heterozygous females suggest that each such male carries either the ms or the ms+ allele, but never both. This confirms early cytogenetic studies on oogenesis which indicated that the male rotifer arises by parthenogenetic development from a haploid egg, produced by ordinary meiotic maturation divisions.
An investigation on the swimming reaction of the anemone Stomphia coccinea. II. Histological location of a reacting substance in the asteroid dermasterias imbricata
Authors: Ward Jack A.
Published: June 2005

The sea anemone, Stomphia coccinea, propels itself through the water by a series of whip‐like swimming motions when stimulated by the asteroid Dermasterias imbricata. It has been previously concluded that the reacting substance is located only in the coelomic fluid and in the aboral surface of this asteroid. The general histology of the body wall of Dermasterias indicates this asteroid is atypical to other asteroids. The dermis of the aboral surface is unique. This tissue has a spherule cell which is abundant, measures 28–32 μ and is not found on the lateral or oral surfaces.

Histochemically the material in dermal spherules correlates well with the chemical properties of a stimulatory carbohydrate previously isolated from this tissue. It is probable that the stimulatory substance that causes Stomphia to swim is related to or identical witht his material.

A prey‐predator relationship for the swimming response cannot be substantiated for the specific case of Dermasterias as the stimulatory asteroid. The response can only be considered a chemoreceptive phenomenon.
Effects of testosterone and gonadotropins on spermatogenesis in Rana pipiens schreber
Authors: Basu S. L. , Nandi Jean
Published: June 2005

The normal seasonal cycle of spermatogenesis in the testis of Rana pipiens was studied, and the effects of several experimental manipulations on spermatogenetic activity were analyzed. Maintenance of control frogs at 26°C, the temperature to which our experimental animals were exposed, was found to enhance spermatogenesis in all cases. Even the most inactive winter frogs showed spermatogenetic progress up to the primary spermatocyte stage under these conditions.

Hypophysectomy inhibited spermatogenesis in all cases. Treatment of hypophysectomized frogs with gonadotropins (FSH plus LH) partially restored spermatogenetic activity. Testosterone treatment inhibited spermatogenesis at the secondary spermatogonial level. Spermatogenetic inhibition by testosterone occurred in intact animals during all seasons of the year, and also in hypophysectomized frogs treated with gonadotropins. Treatment of hypophysectomized frogs with testosterone resulted in greater suppression of spermatogenesis than that observed after hypophysectomy alone. It is therefore suggested that, in Rana pipiens, this spermatogenetic inhibition occurs primarily by a direct action of exogenous testosterone on the seminiferous epithelium.
The effects of electrophoretically separated lens proteins on lens regeneration in Diemyctylus viridescens
Authors: Smith Stephen D.
Published: June 2005

In the present study, lenses were removed from the eyes of adult anesthetized newts, macerated in 0.03 M borate buffer at pH 8.6, and separated by starch gel electrophoresis. Upon staining with amido black 10‐B, seven distinct staining areas appeared in the blocks. Three bands moved toward the anode, and three toward the cathode. In addition, a seventh moiety represented by a smear of material moved toward the anode. One millimeter times five tenths millimeter plugs were removed from each of these areas and were placed into freshly lentectomized eyes. Plugs from most strongly positive and most weakly negative proteins inhibited lens regeneration. In addition, plugs from the area containing the weakly negative protein induced either lenses with aberrant polarity or double centered lenses with centers of opposed polarity. All other protein bands had no significant effect on regeneration.

In addition to the above experiments, homogenates and proteinase‐digested homogenates of lenses were injected into eyes following lentectomy. Three 5‐μl samples were injected in each case over a six day period. Injection of the plain homogenate stimulated lens regeneration markedly, while the proteinase destroyed the stimulatory activity.

Theoretical considerations of the above data are discussed.
A quantitative study of forelimb innervation in relation to regenerative capacity in the larval, land stage, and adult forms of Triturus viridescens
Authors: Peadon Annie M. , Singer Marcus
Published: June 2005

The nerve fibers present at the amputation surface of the upper arm of the land stage and larval newt were counted and compared with values previously published by one of us on the adult. When expressed per unit area of surface, it was observed that the limb of the larva and the small land forms is more highly innervated than that of the adult. The values were 75.5, 47.6, and 27.7 fibers per (100 μ)2 respectively for the larval, small land stage, and adult animals. The number of fibers per unit area of the larger land forms resembled that for the adult showing that the innervation ratio stabilizes at a time before the animal returns to water.

Calculations were also made of the number of motor and sensory fibers in the individual brachial nerves of the younger animals. Assuming the same quantitative threshold of nerve fibers is required to evoke regeneration of the limb in the young animal as is needed in the adult, it was possible to predict the effectiveness of each nerve and nerve component in supplying the neural requirement for regeneration. For example, we found that nerve 5, ineffective in itself to cause regeneration in adults, should evoke regrowth in younger forms, particularly in larvae. The predicted results correspond with experimental ones already published in the literature. The quantitative studies reported herewith are evaluated and discussed against the background of the important action of the nerve in regeneration of a body part.
Fine structure of the prostatic epithelium of the opossum (Didelphis virginiana Kerr)
Authors: Hruban Z. , Martan J. , Slesers A. , Steiner D. F. , Lubran M. , Rechcigl M.
Published: June 2005

The opossum prostate is highly complex cytologically, containing six different secretory cell types, each possessing a recognizably different secretory product. Secretory granules in cells of the first segment contain numerous particles 60 Å in diameter of high electron density. They are transferred to the lumen by apocrine secretion. Both granules and lumina contain iron (Turnbull blue reaction). Segment two possesses three cell types. Type A cells have spherical secretory granules containing acid mucopolysaccharides. In type B cells, secretory granules are elongate and possess densely packed protein filaments, 80 Å in diameter. Secretory granules in type C cells contain crystalloids of hexagonally packed cylinders with a spacing of 600 Å. Third segment cells contain few organelles and have a broad irregular microvillar border. Most of the cytoplasm is filled with glycogen particles. The secretion is apocrine. The lumen contains lipoprotein lamellae, probably derived from shed microvilli, and also membrane bound glycogen globules originating from the cytoplasm. The contents are positive for acid, di‐ and tri‐phosphatases and peroxidase. Catalase activity in the third segment is unusually high.
Electrophoretic studies of cholinesterases in brain and muscle of the developing chicken
Authors: Maynard Edith A.
Published: June 2005

Acrylamide 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

Attempts 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

A 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

Tail 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

The 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

Treatment 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

Previous 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

The 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

Chick 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

Eggs 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

Spots 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

Individual 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

The 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

The 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

Skin 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.
Inhibition of thyroxine induced tail resorption in vitro by pituitary grafts from different stages of metamorphosis
Authors: Derby A.
Published: June 2005

It has been previously demonstrated that isolated pieces (discs) from the tail fins of tadpoles (R. pipiens), survive in vitro for several weeks and respond to thyroxine by undergoing resorption. In addition, discs into which tadpole pituitary glands have been implanted or discs that have been injected with either prolactin or growth hormone undergo a delayed pattern of resorption on expsoure to thyroxine when compared to discs treated with thyroxine alone.

Pituitaries were taken from early prometamorphic, climax and froglet stages and were implanted into tail discs cut from tadpoles in early prometamorphosis. These discs were maintained in thyroxine solutions. As controls, unimplanted discs were treated with thyroxine or maintained in Hanks solution. In a second series of experiments, tail discs were cut from tadpoles at progressive stages of prometamorphosis and treated with thyroxine solutions.

The results demonstrate that pituitaries taken from different stages in the life cycle of this animal differ in their capacity to inhibit thyroxine induced tail resorption. The most effective inhibition is demonstrated by early prometamorphic pituitaries, followed by climax pituitaries. Froglet glands exhibit little activity. The results also demonstrate that the response of tail tissues to thyroxine increases during early prometamorphosis and with increasing rapidity during the last third of this period. These results are in harmony with the concept that amphibian metamorphosis may be dependent upon a bihormonal system in which thyroid hormone promotes while a prolactin‐like hormone counteracts this process.
Histopathology of skin allograft rejection in larval Rana catesbeiana
Authors: Baculi Buena S. , Cooper Edwin L.
Published: June 2005

First‐ and second‐set skin allografts were exchanged and single autograft controls performed in American bullforg larvae at 25 ± 1°C. Rejected allografts, along with lymph glands, thymus, spleen, liver, kidney and intestine, were examined for histopathologic changes. First‐set survival times showed a range of 18–23 days and rejection was initiated by dissemination of pigment cells throughout the epidermis. Breakdown of the epidermis and invasion of the dermis by lymphocytes and fibroblasts began during the first week. Concomitant with breakdown during the second week, re‐epithelialization of the graft periphery and formation of a new, highly cellular dermis occurred. The dermis was the last to be destroyed, which prior to its destruction appeared initially as a thick, homogeneous, eosinophilic, almost acellular mass, gradually replaced by a cellular connective tissue. Increased numbers of mitoses, large lymphocytes and blast cells appeared in the lymph glands, spleen and liver prior to cellular infiltrations of allografts; small lymphocytes, however, still predominated. Eosinophils became prominent in the epidermis, kidneys and liver during the early stages of rejection.

Second‐set survival ranged from 7–10 days and rejection was much more abridged with less congestion. Although the onset of rejection was variable, once it was initiated the process went to completion acutely. Lymphocytic and fibroblastic reactions were more intense than in first‐set rejection; small lymphocytes were quite prominent in lymph glands, spleen, liver and intestine. Lymphoid follicles in the liver and intestinal wall were generally larger than in the first‐set group. All control autografts were normal, intact skin; the control sections through intestines showed very minimal lymphocytic accumulations.
Histology and ultrastructure of untreated forty‐eight‐hour canine renal transplants
Authors: Lemanski Larry F. , Bertke Eldridge M.
Published: June 2005

The histology and ultrastructure of 48 hour renal transplants between unrelated canines was studied. Included in the investigation were eight normal, four autografted, and four allografted kidneys. The autografted organs showed no histological or ultrastructural changes when compared to normal contralateral controls. Light microscopy of the 48 hour allografts revealed extensive leukocytic infiltration and general cellular disruption with accumulations of lipid material and desquamated cytoplasm. Ultrastructural changes in glomeruli of allografted organs included thickening of the capillary basal lamina, enlargement and fusion of podocyte processes, accumulation of debris in the capillary lumens, and increase in blood platelets within the capillaries. Cells of both proximal and distal convoluted tubules showed mitochondrial swelling and disruption, cytoplasmic vacuolization, and accumulations of lipid material. Evidence of endothelial disruption in intertubular capillaries was observed. No changes were observed in the loops of Henle, collecting ducts or larger blood vessels. The results showed that tissue destruction reached an irreversible state by the 48 hour stage of allografting. The presence of plasma cells at this early stage implicated them in the rejection reaction.
Changes in level of activity of NAD‐dependent and NADP‐dependent isocitrate dehydrogenases during the development of the chick spinal cord
Authors: Burt Alvin M.
Published: June 2005

The specific activities of threo‐Ds‐Isocitrate:NAD oxidoreductase (E.C.1.1.1.41; NAD‐ICDH) and threo‐Ds‐Isocitrate:NADP oxidoreductase (E.C. 1.1.1.42; NADP‐ICDH) were measured in the brachial spinal cord of chick embryos ranging in development from 3.5 to 21 days' incubation. The activity of NAD‐ICDH increased gradually throughout the developmental period studied and appeared to be similar ontogenetically, with other enzymes of the citric acid cycle. The ontogenetic pattern of NADP‐ICDH, on the other hand, was quite different. The enzymatic activity increased rapidly from 3.5 to 7 days' incubation and then increased at a slower rate throughout the remainder of development. The temporal changes in activity of both enzymes are discussed in relation to other enzymes of intermediary carbohydrate metabolism and to the processes of neuroblastic growth and differentiation. The results of this study suggest that NADP‐ICDH is the major source of reduced NADP for the reductive syntheses associated with neuroblastic growth and differentiation whereas glucose‐6‐phosphate dehydrogenase and the pentose cycle provide the major source of NADPH during the preceding period of rapid proliferation and early differentiation.
Sperm migration prior to fertilization in the hydroid Gonothyrea loveni
Authors: Miller Richard L.
Published: June 2005

The medusiform, gamete‐bearing sporosacs (meconidia) of Gonothyrea are pushed out of the gonangium but remain attached to its distal end. The female meconidium is known to secrete a substance capable of attracting the sperm chemotactically. If sperm approaching the female meconidium pass close enough to one of its tentacles, they stick to the tentacle by their tails and appear to be suspended a few microns above the surface of the tentacle ectoderm cells. They then begin to migrate along the tentacle, eventually arriving at the base where they can enter the meconidium. The direction of movement while on the tentacle surface cannot now be directly related to the source of the chemotactant. The propulsive source is the sperm flagellum, though the beat is markedly suppressed over most of its length. An extracellular surface coat is probably responsible for both the adherence to the tentacle and the suppression of motility of the flagellum. Comparative tests using other genera show that the sperm of Campanularia flexuosa does not stick to the female Gonothyrea meconidium tentacles, but those of C. calceoliferaa do. The specificities are maintained in the reverse case, as well as when active extracts are used against the sperm.
Differentiation of ganglionic cells in Hydra
Authors: Davis Lowell E.
Published: June 2005

The differentiation of ganglionic cells in Hydra has been studied at the level of the electron microscope. These cells originate solely from interstitial cells and not from pre‐existing nerve cells. In addition, the evidence suggests that ganglionic cells do not represent a stage in the development of other nerve cells, i.e., neurosensory and neurosecretory cells. Some of the major cytoplasmic changes in fine structure during differentiation include the formation of neurites, development of Golgi complexes, the appearance of microtubules throughout the neurites, the presence of numerous ribosomes, most of which eventually disappear during development. It is believed that the three types of neurites described may reflect different forms of basically one type of neurite.
Effects of temperature on the kinetics of malate dehydrogenases in the developing eggs and adult muscle of Ascaris lumbricoides (Nematoda)
Authors: Barrett John , Fairbairn Donald
Published: June 2005

The effects of temperature on the kinetics of the different cytoplasmic malate dehydrogenases which are present during the life cycle of Ascaris lumbricoides were studied. Aerobic development of the eggs occus below 32°C, whereas anaerobic energy metabolism in adults occurs at 38–40°C. Eggs developed for one day have one cytoplasmic MDH (MDH‐1), fully developed infective 21‐day eggs have 3 dehydrogenases (MDH‐1, 2, 3) and adult muscle has the same three isozymes but in proportions favoring MDH‐2 and 3. Values for Vmax, energy of activation, and the thermal stability of the total enzyme or of individual isozymes were not clearly correlated with temperature changes occurring during the life cycle. In contrast, the apparent Michaelis constants (Kma) were directly correlated. The Kma of MDH‐1 and MDH‐3 passed through minima at 25°C and 38°C, respectively; the Kma of MDH‐2 showed no clear minimum. The distribution of the isozymes during development was such that the Kma of total malate dehydrogenase at one day, 21 days, and in adult muscle was minimal at 25°C, 30°C, and 38°C, respectively. The result are considered in terms of epigenetic adaptation, i.e., malate dehydrogenase in one‐day eggs and adult muscle is adapted to function efficiently at temperatures normal to those stages, whereas infective eggs also possess large amounts of isozymes which are probably only functional during the succeeding stages of development.
Protein biosynthesis after lens rotation: An immunoelectrophoretic analysis in the chick embryo
Authors: Génis‐Gálvez J. M. , Castro J. M.
Published: June 2005

An experimental, immunological analysis was performed to observe whether induced fiber cell formation in the chick lens can be correlated with the biosynthesis of a specific crystallin. As a result of lens inversion, epithelial cells abruptly elongate. In these elongated cells crystallin determinants were uniquely predominant These results seem to indicate that the quiescent genome of lens epithelial cells can be activated with an appropriate artificial stimulus. Moreover, biosynthesis of delta crystallin, at least initially, seems to be strongly correlated with morphological features of lens fiber differentiation.