bluuebunny/crossref_metadata_2025 huggingface dataset:
The regulation of alkaline phosphatase activity in the duodenum of the mouse from birth to maturity
Authors: Moog Florence
Published: June 2005

Actinomycin D elevates the alkaline phosphatase activity of the duodenum of the mouse. The effect is relatively slight, but positive, during the first postnatal week, but thereafter becomes marked, not only in the period before the normal maximal level of phosphatase activity is reached at 20 days, but also afterwards, as the activity declines to the adult level. The effect is not manifested in mice at the age of one month, but reappears in adults. Doses of actinomycin that enhance duodenal phosphatase activity depress the activity of the same enzyme in the kidney.

Puromycin also increases duodenal phosphatase activity, the effect again being quite small in the first week. At all stages from nine days to adult, however, puromycin strongly elevates activity. Cycloheximide is also effective in raising duodenal phosphatase activity in young mice.

Glucocorticoids are known to control the normal developmental increase of phosphatase, but the effect of actinomycin D can be exerted in adrenalectomized mice. The effects of both actinomycin and puromycin are additive with those of hydrocortisone acetate, and both raise phosphatase activity after 15 days, when exogenous corticoids no longer exert any influence.

Puromycin stops mitosis in the duodenal epithelium in doses that elevate phosphatase. Hence, some alteration of the enzyme must occur in the striated border of cells that have emerged from the crypts and are in place on the surfaces of the villi. Since the phosphatase‐stimulating agents are all inhibitors of protein synthesis, the results are interpreted to mean that duodenal phosphatase normally tends to undergo an activity‐enhancing conversion that is restrained by a labile protein.
Electron microscopic studies of planaria. III. Some observations on the fine structure of planarian nervous tissue
Authors: Morita Michio , Best Jay Boyd
Published: June 2005

The small size of the nerve fibers of the planarian nervous system render the details of its neuroanatomy invisible to optical microscopy. Electron microscopic studies on the nervous system of Dugesia dorotocephala are described showing the neuropil of the brain, the origin of the ventral nerve cords from the brain neuropil, synaptic junctions in the neuropil, and “giant” fibers in the longitudinal conduction system. Two major kinds of synapses can be discerned as well as the pre‐ and post‐synaptic sides of each. There appear to be three major kinds of cells comprising the brain; neurons, neurosecretory cells, and neuroaccessory cells. The neurons are unmyelinated, contain neurotubules, and appear to synapse only in the centrally located neuropil.
Chemotaxis during fertilization in the hydroid Campanularia
Authors: Miller Richard L.
Published: June 2005

The pre‐fertilization behavior of the sperm of the thecate hydroids Campanularia flexuosa and Campanularia calceolifera has been observed and recorded by means of dark‐field cinephotomicrography. The sperm of both species activate and aggregate homotypically around the aperture of the female gonangium. Plots of the paths of sperm approaching the aperture show that the aggregations are the result of directed turning movements and not of so‐called trap‐actions or an increased random turning of the spermatozoa. An aperture‐associated tissue of ectoderm origin has been found to produce the attractive substances.

Active sea water and alcohol extracts of female gonangia of C. calceolifera have been prepared. The substance affects sperm in the same ways as the material released by the female gonangium. The active material is heat stable, non‐volatile, dialyzable, polar, and appears to be a single molecular species of less than 5,000 mw. Injection of these extracts into sperm suspensions by means of a micropipette produces activation and aggregation of only the sperm of C. calceolifera about the pipette tip. If agar impregnated with the chemotactant is used as a source, the sperm are seen to orient with considerable accuracy. Extraction of C. flexuosa female gonangia has not yielded active extracts.

These results demonstrate that chemotaxis does occur during fertilization in an animal. The mechanism of the reaction remains to be determined.
A variant of lactate dehydrogenase in somatic tissues of pigeons: Physicochemical properties and genetic control
Authors: Zinkham William H. , Kupchyk Luba , Blanco Antonio , Isensee Harriet
Published: June 2005

Three genetic loci (a, b, and c) control lactate dehydrogenase synthesis in many mammalian and avian species. A survey of the lactate dehydrogenase isozyme composition of somatic tissues from approximately 1,000 wild pigeons revealed three phenotypic classes. The frequency distribution of the three classes in wild pigeons and the results of appropriate breeding experiments demonstrated that the phenotypic differences were due to alleles at the b‐locus. One of the alleles produces a B' polypeptide with an electrophoretic mobility identical to that of the A polypeptide, but with substrate affinity and heat inactivation properties similar to those of the B polypeptide.
Some comparative fine structure relationships of the rotifer integument
Authors: Koehler James K.
Published: June 2005

Species representing three rotifer genera have been investigated with special emphasis on elucidating the detailed fine structure relationships of integumental derivatives. The classical concept of cuticulization in these animals must be modified to incorporate the finding that a genuine extracellular cuticle is lacking in a species thought to be very heavily cuticulized (loricate) namely, Keratella cochlearis. A consistent intracellular structural entity located just beneath the hypodermal plasma membrane is thought to represent the bulk of the reinforcing or exoskeletal material observed in all rotifers thus far examined. In Philodina, this “dense layer” is shown to be an insertion point for fiber tracts associated with muscle‐hypodermis desmosomes. The desmosomes are of interest in themselves since they are not of the septate type observed previously in rotifers and invertebrates in general, but are of the “standard” variety more commonly seen in higher animals.
Electrokinetic properties of dissociated chick embryo cells. I. Ph‐surface charge relationships and the effect of calcium ions
Authors: Collins Michael
Published: June 2005

Since the electrokinetic properties of a particle depend entirely upon the particle's surface, microscopic electrophoresis of dissociated cells can yield information about the cellular surfaces. Dissociated heart ventricle and liver cells from five‐day chick embryos as well as neural retinal cells from seven‐day embryos have been examined electrophoretically over a wide pH range and the pH‐net surface charge density relation for each type of cell has been determined. Under the conditions selected the cells show differences with respect to these relations which appear to reflect differences in the molecular composition of the cells' surfaces.

Since intercellular adhesion may occur through bivalent cation bridges with calcium being the cation most likely to be involved, the suppression of surface charge density by means of calcium ions at physiological concentration has been determined at physiological pH for heart ventricle, liver, neural retinal, and back epidermal cells. The degree of charge suppression, which varies among cells of different types, can be correlated with the apparent cellular adhesiveness as judged from sorting out behavior in some but not all cases.

Dye exclusion, the ability of cells removed from the electrophoresis apparatus to reaggregate, and the reversibility of pH effects and calcium effects have been used to try to detect damage to the cells caused by experimental conditions. The results of these tests have seemed satisfactory.
Electrokinetic properties of dissociated chick embryo cells. II. Calcium ion binding by neural retinal cells
Authors: Collins Michael
Published: June 2005

Since embryonic cells may be bound together by calcium ions forming bridges between negatively charged sites on the cellular surfaces, it is important to show that embryonic cells can bind calcium ions and to learn something of that binding. Neural retinal cells from seven‐day chick embryos have been dissociated and prepared for microscopic electrophoresis in three different ways. Their electrophoretic mobilities and surface charge densities have been determined over a range of calcium concentrations. The progressive reduction of charge density with increasing calcium concentration, with ionic strength held constant, clearly indicates calcium binding at the cellular surface.

The data contained herein permit one to calculate a binding constant for the calcium‐binding site complex, the number of sites per cell surface, the average distance between them, the percentage of sites occupied by calcium ions at physiological calcium concentration, and the fraction of anionic sites on the cell surface which bind calcium. They also indicated that trypsin dissociation may remove calciumbinding material from cellular surfaces and suggest that that material may be regenerated during incubation in culture medium.
Tissue transplantation immunity in the adult newt, Diemictylus viridescens. I. The latent phase: Healing, restoration of circulation, and pigment cell changes in autografts and allografts
Authors: Cohen Nicholas
Published: June 2005

Following the allogeneic transplantation of dorsal pigmented skin to the throat and flank of field collected adult Diemictylus viridescens there was, at 23 ± 0.5°C, a long latent period of about 16 days when such grafts were histologically and grossly indistinguishable from autografts.

Circulation was usually restored in autografts and allografts between 10 and 11 days post‐grafting apparently by end to end anastomoses of graft and host vessels. Restoration of circulation was usually preceded by an initial dilation of the grafts' vessels and by the trauma induced death of some melanophores.

An approximate five fold increase in the thickness of the dermal collagen of all grafts was noted throughout the latent phase as well as during graft rejection.
Parental influences on lactate dehydrogenase in the early development of hybrid frogs in the genus Rana
Authors: Wright David A. , Moyer Frank H.
Published: June 2005

The lactate dehydrogenase (LDH) isozymes of Rana pipiens pipiens, R. p. sphenocephala, and R. palustris were examined. LDH‐5 in all three organisms has the same electrophoretic mobility. There is a group of three to five bands in the LDH‐1 position which migrates fastest in R. pipiens sphenocephala, at an intermediate rate in R. pipiens, and slowest in R. palustris. Analysis of this multiple banding in the LDH‐1 position in R. pipiens suggests that these bands are distinct molecular forms. When the reciprocal crosses are made between frogs with different LDH patterns the maternal pattern persists in the embryo until stage 19 (heart beat) when hybrid and paternal bands first appear. The maternal contribution to the LDH pattern remains high, however, until stage 25 (feeding).

In Rana sylvatica there are at least eighteen bands showing LDH activity. There are five bands in the LDH‐1 position, and the rest of the bands can be grouped into LDH‐2, LDH‐3, LDH‐4, and LDH‐5, all showing multiple bands. In the normal development of R. sylvatica there are marked shifts in the banding patterns in the LDH‐3, LDH‐4, and LDH‐5 groups between neurula and hatching, suggesting differential synthesis of the subunits forming these isozymes. In crosses between normal R. sylvatica females and a variant male which has additional bands in the LDH‐1 position, the paternal type bands appear after hatching.
Genetic analysis of three lactate dehydrogenase isozyme systems in trout: Evidence for linkage of genes coding subunits A and B
Authors: Morrison William J. , Wright James E.
Published: June 2005

Lactate dehydrogenase (LDH) isozymes of two genera within the family Salmonidae (Salvelinus and Salmo) were examined by acrylamide and starch gel electrophoresis. Those species examined contain three isozyme series involving five different kinds of subunits. The A‐B series, believed to be homologous to LDH 1–5 in the majority of vertebrates, is found in nearly all tissues. Polymorphism for subunit B was discovered in Salvelinus fontinalis in which two kinds, B and B', are present within a number of inbred strains. Various crosses and backcrosses involving S. fontinalis and Salvelinus namaycush demonstrate that subunits A and B are each coded by different autosomal genes (LA and LB). A limited amount of test‐cross data indicates linkage of these genes. Partial genetic analysis indicates that a second series of several LDH isozymes, largely restricted to the retina, involves a third subunit, C, in combination with B and to a lesser extent with A. A variant form of subunit C was found in Salmo trutta. Comparison of patterns of S. fontinalis and S. trutta and their hybrid seems to indicate that two additional subunits are involved in a third series of five isozymes found in the skeletal muscle of each species examined.
Nuclear activation at the onset of amphibian gastrulation
Authors: Bachvabova Rosemary , Davidson Eric H.
Published: June 2005

A quantitative radioautographic study of RNA synthesis in the diverse cell types of the Xenopus blastula and gastrula is described. Nuclear activation, studied as increase in the number of grains in nuclear RNA after pulse‐labelling with uridine H3, was found to occur abruptly just before gastrular movements become observable. Presumptive endoderm and mesoderm participate in this widespread activation, while presumptive ectoderm becomes activated shortly after, at mid‐gastrulation. It is shown that per‐nucleus rates of high molecular weight, non‐ribosomal RNA synthesis increase at least 20 fold within one hour in endoderm and mesoderm as the embryo prepares to enter gastrulation.
Development of the fertilizing ability of spermatozoa in the epididymis of the rabbit
Authors: Bedford J. M.
Published: June 2005

When spermatozoa from specific segments of the epididymis were inseminated intra‐tubally, ten hours before ovulation, virtually no ova were fertilized by sperm samples taken from the regions proximal to the middle of the corpus epididymidis. Sperm from the caput epididymidis and the proximal half of the corpus region not only fail to fertilize, but are also apparently unable to establish contact with the surface of the zona pellucida. Although a maximal fertilization rate was obtained with sperm samples from the lower part of the corpus epididymidis, significantly greater numbers of supplementary and zona surface spermatozoa were found in association with tubal ova exposed to similar numbers of sperm from the cauda epididymidis. This latter finding suggests that the cauda region contains a relatively higher percentage of mature spermatozoa, and thus that a proportion of spermatozoa do not become functionally mature until they have passed from the corpus epididymidis.

Approximately 7% and 5% of ova exposed to spermatozoa from the lower corpus and cauda regions, respectively, contained three and occasionally four pronuclei, quite probably as a consequence of polyspermic fertilization. As no polyploid ova were found after similar exposure to greater numbers of ejaculated spermatozoa (Adams and Chang, '62), it is conceivable that there may be other systems on the sperm head, as well as those concerned with penetration of the zona, which also mature in some way during epididymal passage.
Structure and function in the third abdominal ganglion of the crayfish Procambarus clarkii (Girard)
Authors: Kendig Joan J.
Published: June 2005

The functional anatomy of the crayfish third abdominal ganglion was explored by reconstructions from silver‐stained serial sections and by intracellular recording from units in the neuropile. Fibers entering the ganglion from the ventral nerve cord and the peripheral nerves from bundales with different paths and destinations. These bundles and other anatomical features such as commissures and cell body groups are constant from animal to animal, as are the positions of individual fibers and their branches. Organization in the ganglion is not based on topographical representation of the periphery, but there is a relation between the functions of individual fibers and their positions. Some of the bundles consist of fibers with similar or related functions. The orderliness, constancy and functional relations of the anatomy point toward specific anatomical connectivity between fibers in this preparation.
Sex pheromone of the mealworm beetle. (Tenebrio molitor)
Authors: Tschinkel Walter , Willson Clyde , Bern Howard A.
Published: June 2005

Sex pheromone activity from female mealworm beetles (Tenebrio molitor) may be extracted and quantified by fractional population response of virgin adult males, which attempt copulation with any pheromone‐treated object. Extracts of mature males can be shown to elicit identical behavioral activity, although at lower individual concentration. Since response to the pheromone is sex‐specific, its apparent production by both sexes of T. molitor is especially noteworthy. It has been shown that the presence of pheromone in males cannot be due to contamination by females.

Both pheromone production and the male response are undetectable in newly‐emerged adults; both rise to their maximum extent within one week of eclosion.
Flagellar Development in the Protozoan Peranema trichophorum,
Authors: Tamm Sidney L.
Published: June 2005

Changes in flagellar length during the developmental events of flagellar replication and flagellar regeneration were investigated in single cells of the colorless euglenid flagellate Peranema trichophorum at known stages in the life cycle. The leading flagellum could be cut off at any desired length with a tungsten knife operated by a micromanipulator, and the regeneration process recorded photographically.

In the regeneration of a flagellum by a postdivision cell, there is a short lag period followed by an elongation with a deceleratory rate. The relationship between elongation rate and flagellar length holds true regardless of the initial stump length. The elongation rates at given lengths are greater in predivision cells than in postdivision cells.

At cell division, the parental leading flagellum rapidly shortens at a constant rate and disappears, while simultaneously two new leading flagella elongate at a deceleratory rate. Elongation continues at slower rates throughout interphase.

The elongation kinetics of the flagellum during the normal cell cycle, and the kinetics of regeneration at different cell ages have been satisfactorily accounted for by a mathematical model.

Shortening and elongation were compared and the relationship between them was discussed in light of the finding that shortening interrupted regeneration in some predivision cells.

It was concluded that at least part of the control exerted over flagellar length changes resides in the flagellum itself.

The lag period remained the same under a variety of experimental conditions, suggesting that it is a “wound healing response”.
Fine structural changes during sea urchin oogenesis
Authors: Verhey Catherine A. , Moyer Frank H.
Published: June 2005

Fine structural changes during sea urchin oogenesis are described and related to functional changes in the developing ovum. A staging sequence based on the morphology associated with the synthesis of ribosomes, cytomembranes, and yolk and cortical granule proteins is proposed: the oogonium, in which the cytoplasm contains a few scattered mitochondria, lipid inclusions and free‐floating ribosomal aggregates; the first transition stage, in which annuli form in the nuclear envelope and ribosomes become attached to newly synthesized cytomembranes; the vitellogenesis stage, in which the cytoplasm becomes packed with yolk and cortical granules, mitochondria, and lipid droplets; the second transition stage, in which annulate lamellae are delaminated from the nuclear envelope; and the mature ovum, in which the annulate lamellae are distributed throughout the cytoplasm and begin to break down into rough‐surfaced vesicles. Typical Golgi apparatus is first observed at this stage. The plasma membrane forms microvilli and there is a thick jelly layer.

The association of ribosomes with cytomembranes and an amorphous material is discussed with respect to their activity in protein synthesis. The relationship of the accessory cells to the developing oocyte is also discussed.
Differential behavior of anterior and posterior embryonic chick somites in Vitro
Authors: Lash James W.
Published: June 2005

The posterior somites of young (stages 15–18) chick embryos have a greater chondrogenic potential in tissue culture than do the anterior somites from the same embryo. Approximately 70% of posterior somite clusters will form cartilage nodules in tissue culture, whereas only 15–20% of anterior somite clusters form nodules. Paradoxically, when randomized anterior + posterior somites are cultured together, the incidence of cartilage formation is lower than expected. Randomized anterior + posterior somite clusters have the same incidence of cartilage formation as do anterior somites alone.

Somites from either region, if cultured in the presence of embryonic notochord tissue, exhibit 100% cartilage formation.

The chondrogenic potential of the somites may be correlated with their histo‐architecture and their embryonic history.
Electrophoretic and kinetic properties of Rana pipiens lactate dehydrogenase isozymes
Authors: Goldberg Erwin , Wuntch Thomas
Published: June 2005

Lactate dehydrogenase of Rana pipiens exists in at least three isozymic forms. Extracts from heart tissue contain all three isozymes, and extracts from the gastrocnemius muscle contain only one isozyme. LDH extracted from testis is identical to that from the heart. The isozymes are tetramers of about 140,000 molecular weight. The five possible tetramers of LDH are not formed in frog preparations by the freeze‐thaw method applied so successfully to mammalian LDH.

Kinetic data show that heart LDH exhibits substrate inhibition at lower substrate levels than does muscle LDH and that all the isozymes have a lower apparent Km value for pyruvate than for lactate.

Thermal inactivation is a first order, unimolecular event with more heat energy required to inactivate the heart extract. Since inactivation of heart LDH occurred at a lower temperature and with considerably greater disruption of the molecule, the isozyme of muscle LDH has the more stable conformation.

Synthesis of lactate dehydrogenase in this species appears to differ from the usual case of random association of subunits into tetramers. Homodimers may be formed first and then randomly associate to form homo‐ or hetero‐tetramers.
Selfing in Paramecium aurelia, syngen 5: Persistent instability of mating type expression
Authors: Bleyman Lea Kanner
Published: June 2005

One class of caryonides in stock 210, syngen 5 of P. aurelia, designated mc S, was found to be a persistent selfer. Cells of complementary mating type (IX and X) regularly appeared in cultures of the selfer caryonides. Type IX and type X cells arose independently of each other as mating reactivity began in the cultures. While the type X cells remained type X during their period of sexual reactivity, the type IX cells in some cases changed to type X. This unidirectional change of mating type in single cells occurred within an hour. Cell division was not required for the change. Under certain conditions, the expression of type IX was suppressed and cultures of mc S caryonides contained solely type X cells.

Similar unidirectional changes of mating type (from odd to even) occur in other syngens of P. aurelia. In these cases, as well as in those species of ciliates where persistent selfing occurs, variable gene activity seems the most likely explanation for the unstable mating type expression.
The ontogeny of lactate dehydrogenase in the chick cornea
Authors: Alcorn S. , Maisel H.
Published: June 2005

The activity of the enzyme lactate dehydrogenase during development of the chick cornea was investigated by starch gel electrophoresis and by spectrophotometric analysis. The isozyme pattern of the cornea prior to the fourteenth day of incubation shows a predominance of LDH 1–3. During subsequent development, there is a marked increase in LDH 4 and 5, so that at hatching, LDH 2–5 stain with nearly equal intensity while LDH 1 shows less activity. From about ten days after hatching, the isozyme pattern is characterized by the presence of LDH 1–5 with isozymes 4 and 5 predominant as in the adult cornea. The period of increase in cathodal isozymes coincides with the time of appearance of corneal transparency, and probably reflects a change in metabolic activity occurring at this time of development.
Reduced blood supply to the uterus as a cause for early embryonic death in the mouse
Authors: Senger P. L. , Lose E. D. , Ulberg L. C.
Published: June 2005

Limitation of blood supply to the developing embryo of the mouse was accomplished by electrocoagulation of the blood within the vessels supplying one horn of the uterus. When blockage of both the uterine artery and vein and the secondary vessels was performed before mating, 35.6% of the ova, as represented by corpora lutea (CL), were present as implantation sites at autopsy, ten days post coitum (ten days); 91.1% of the ova (CL) were present as implantation sites on the control side. During the time between electrocoagulation and mating (average, 8.3 days), some reestablishment of circulation had usually occurred. When unilateral coagulation was performed at one day and at five days, 2.6% and 14.6% of the ova, respectively, subsequently formed implantation sites.

When alternate secondary branches of the uterine blood supply to one horn were coagulated at one day, 40.6% of the ova resulted in implantation sites at ten days. Tertiary arborizations of undisturbed branches appear to revascularize portions of the horn to which the blood supply had been coagulated. When blood supply to the ovarian, middle or cervical portions of the uterus was blocked at one day, 6.3%, 42.9% and 14.3% of the ova, respectively, formed implantation sites. It is suggested that the blood supply to the ovarian portion of the uterus is critical to the descending embryo.

There was a significant correlation between the number of secondary vessels and the number of implantation sites in all intact uterine horns.
Environmental control of annual testicular cycles in the lizard Anolis carolinensis. I. Interaction of light and temperature in the initiation of testicular recrudescence
Authors: Licht Paul
Published: June 2005

Adult male Anolis carolinensis were placed under several combinations of light and temperature starting in midSeptember to elucidate the environmental factors regulating the initiation of testicular recrudescence (TR). TR normally starts in the fall, proceeds gradually throughout the winter, and is completed in early spring. This pattern appears to be very similar from year to year. TR was greatly accelerated by 14 hours of light daily when body temperatures were kept constant at 32°C; or when body temperatures were fluctuated to emulate a normal thermal cycle (day 32°, night 20°). A pronounced testicular cycle occurred under the latter conditions. If the daily heating (32°) was given at night (with 20°C during the daytime) there was virtually no response to long day‐lengths. A photoperiod consisting of 12 or 6 hours of light daily, with body temperature kept constant at 32°C caused a delay in TR as compared to animals in nature or to those kept at a constant low body temperature (20°C). However, once TR began, it was accelerated by the high temperature.

Photoperiods of 0 to 14 hours of light daily had no influence on the initiation or rate of TR at 20°C. Testes developed at approximately the same rate as in nature. After 150 days, the testes were unusually enlarged but spermatogenic activity was still low.

These data suggest that even though a distinct photoperiodism is evident in Anolis, day‐length probably acts only in a permissive way to facilitate the temperature response which is the more direct modifier of TR. Different aspects of TR may have different thermal requirements. TR may be spontaneously initiated by an “endogenous trigger” and then modified by the thermal relations of the animal.
Congenital eye defects in the mouse. I. Corneal opacity in C57Black mice
Authors: Pierro Louis J. , Spiggle Jean
Published: June 2005

Corneal opactities are observed in a small percentage of C57Black mice. Discrete central opacities are found in eyes of normal size; more generalized opacities are found in eyes which are reduced in size, although large enough to protrude through the eyelids. Corneas with discrete opacities are characterized by a gap in the stroma, and disorganization of the overlying epithelium. Similar stromal defects are found in corneas with more generalized opacties, and, in addition, cornea and iris are continuous along their stromal components. Either anterior polar cataract or anterior lenticonus, defects involving the anterior surface of the lens, are almost invariably found in association with the corneal opacities.

Study of early lens and corneal development in C57Black embryos implicates prolonged attachment of the lens vesicle to the superficial ectoderm in the genesis of the corneal opacities. The persistence of the lens stalk serves as a barrier to migration of the mesenchyme involved in formation of the corneal stroma. Migration of the mesenchyme destined for a role in development of the stroma of the iris may also be hindered. Separation of the lens vesicle from the superficial ectoderm takes place eventually, but stromal development remains defective. Disorganization of the corneal epithelium appears to be a secondary consequence of the defective stroma. Anomalies of the anterior surface of the lens appear to result from problems associated with the abnormal separation of the lens vesicle from the superficial ectoderm.
The embryonic value of the micromeres in Ilyanassa obsoleta, as determined by deletion experiments. I. The first quartet cells
Authors: Clement Anthony C.
Published: June 2005

Each of the first quartet micromeres of Ilyanassa obsoleta has been removed at the 8‐cell stage, and the effect of the loss observed in the larva.

Removal of the 1a micromere resulted in all cases in absence of the left eye; a small reduction in size of the left lobe of the velum could frequently be detected also. In other observed details the larvae appeared complete.

Absence of the 1b micromere resulted in a variable tendency toward synophthalmia, and some indication of reduction in size of the velum. Sporadic abnormalities of other types were encountered in the experimental series.

Loss of the 1c micromere resulted in absence of the right eye, a slight reduction in size of the right lobe of the velum and, probably, absence of the right tentacle.

Removal of the 1d micromere was without observed effect on larval structure in two out of three cases.

The results are compared with deductions from cell lineage work on the related form Crepidula, and they are considered also from the standpoint of regulative capacity. The Ilyanassa embryo shows both mosaic and regulative features.
The relation between the caliber of the axon and the trophic activity of nerves in limb regeneration
Authors: Singer Marcus , Rzehak Karol , Maier Charles S.
Published: June 2005

Previous work from this laboratory demonstrated a relation between ability to regenerate a limb and number of nerve fibers available per unit area of amputation wound. Animals with fewer fibers than the newt, Triturus, (for example, Rana, Anolis, and Mus) do not regrow the limb. An exception appeared in Xenopus whose limb is sparsely innervated and yet which regenerates. The present work demonstrates that the nerve fibers of Xenopus make up in individual size what they lack in number. When the average cross‐sectional area of the axons was multiplied by the number of fibers per unit area, the results showed that the Xenopus limb is about as well supplied with axoplasm as that of Triturus. This was not true for Rana. The results also demonstrate for the first time a direct relation between caliber and trophic effectiveness of the axon, the evolutionary significance of which is discussed.
Studies of frog oviducal jelly secretion. I. Chemical analysis of secretory product
Authors: Lee Peter A.
Published: June 2005

The jelly secreted by the oviduct of Rana pipiens has been analyzed histochemically and biochemically. Histochemical techniques show that the jelly contains neutral carbohydrates and a protein moiety. Colorimetric estimation reveals that the jelly contains protein and also appreciable quantities of hexose and hexosamine. Sialic acid is present. Chromatographic methods were employed to identify the simple sugars, galactose, fucose, mannose, xylose and glucose, and the hexosamines, glucosamine and galactosamine.
Pattern variation in isogenic frogs
Authors: Casler Erika
Published: June 2005

The pigment patterns of groups of genetically identical individuals (clones) obtained by nuclear transfers were compared with individuals arising from normally fertilized eggs in order to ascertain the various factors involved in the formation of the wild‐type pigmentation phenotype of Rana pipiens.

Thirteen experiments were performed. The froglets were killed and photographed and each picture was subjected to a number of examinations and analyses. A thorough visual examination did not reveal any clear differences between the experimental and control groups. The results of the statistical analyses were almost uniform — there was no significant difference in variability with regard to spot number, average spot size, spot location and shape, between the clones and controls. However, the individuals within the clones were more uniform in regard to the percentage area covered by the spots. In transfers involving the nuclei of few‐spotted parents into enucleated ova of few‐ and many‐spotted females, the progeny were of the nuclear type. Rank correlation analyses between parents and offspring indicated that there is a closer resemblance to the mothers than to the fathers.

The results can be explained by the assumption that the genotype, environment, and chance events during development are all implicated in the production of the pigment pattern.
Cellular interactions in the development of the shell gland of the gastropod, Ilyanassa
Authors: Cather James N.
Published: June 2005

To determine the cell lineage of the shell gland in Ilyanassa, the 2d and 2c micromeres were marked with carbon granules. The 2d micromere derivatives form the shell gland, but 2c derivatives are later incorporated into the mantle. Deletion of 2d causes shell abnormalities but, in about 10% of the cases, the shell appears normal although somewhat small. Deletion of 2c also causes characteristic shell abnormalities. After deletion of both 2d and 2c, no shell forms. When 2c is marked and 2d deleted, the shell gland is marked. Any one‐quarter embryo can form internal shell masses. In 1013 isolated ectoblasts (−3A, −3B, −3C, −3D), no shell material formed. Ectoblast with any single macromere formed shell with good morphogenesis, as did ectoblast plus 4d. Posterior ectoblast plus 4d, equivalent in size to isolated whole ectoblast, formed external shell. Properly oriented ectoblast, grown in contact with a polar lobe, formed shell in up to 70% of the cases; in one‐half of these, the shell was external. Deletion of the macromere from an ectoblast plus 3C series of embryos at intervals through the first day resulted in embryos which did not form shell. Ectoblast in contact with polarlobe for six days, then separated, developed shell on the seventh or eighth day. (1) Neither ectoderm nor endoderm in isolation will form shell but any ectoderm‐endoderm combination has the histogenetic ability to form shell material; (2) the endoderm exerts its influence between the second and sixth days of development; (3) only those combinations including or in contat with polar lobe cytoplasm through the third quartet stage undergo normal morphogenesis; (4) transplanted polar lobes can induce ectoderm to form shell; (5) the histogenetic ability to form shell is suppressed or unactivated when polar lobe cytoplasm is present, except in the D quadrant; (6) specialization of the D quadrant is one of the major evolutionary trends in spiralians.
Environmental control of annual testicular cycles in the lizard Anolis carolinensis. II. Seasonal variations in the effects of photoperiod and temperature on testicular recrudescence
Authors: Licht Paul
Published: June 2005

The effects of photoperiod and changing body temperature on testicular growth in Anolis carolinensis vary seasonally. Both a photo‐ and thermal‐refractoriness are evident. During September and October, 14‐hour day‐lengths accelerated testicular recrudescence in lizards at 32°C; a more rapid response occurred during October, suggesting a “relative” photorefractoriness. Photoperiod had little influence on the testicular cycle after October, once testis development started. Day‐lengths between 12 and 16 hours had no effect during any month if body temperatures were kept at 20°C.

Exposures to high temperatures (32°C) in September delayed testicular recrudescence when day‐lengths were 12 hours or less, but after mid‐October, high temperatures accelerated gonadal development, independent of day‐length. These data suggest a thermal refractoriness during September that might be important in preventing premature testicular hypertrophy.

A differential temperature sensitivity was evident among various testicular activities. The testes became abnormally enlarged but spermatogenic development was retarded at 20°C. Spermiation and androgen production appear especially temperature‐sensitive. These temperature sensitivities account for the long (3 month) arrest of spermatogenic development in nature during the winter. The rapid completion of testicular development during the two weeks following emergence from hibernation is probably dependent on elevations in body temperature and not on increased day‐lengths. Temperature, not photoperiod, appears to be the primary factor in controlling testicular recrudescence once it has started. A similar environmental control may explain testicular cycles among other species of lizards.
Relation of resting potential of rat gastrocnemius and soleus muscles to innervation, activity, and the Na‐K pump
Authors: Locke S. , Solomon H. C.
Published: June 2005

The effect of nerve on resting membrane potential of rat muscle was studied. Denervation produces a decline from 83.5 mV in gastrocnemius and from 68.8 mV in soleus to a range of 60 mV. The rate of decline is more rapid with distal than with proximal nerve section. With reinnervation, potential returns to normal. Immobilization, posterior rhizotomy or spinal section produces a decline in gastrocnemius membrane potential to about 70 mV indicating that integrity of ventral root does not prevent a fall. Independence of resting potential and muscle fiber size is indicated by work hypertrophy, by near and distant section of nerve and by variation in resting potential for the same degree of atrophy produced by disuse or denervation.

Existence of a plateau below which resting potential does not decline following denervation is compatible with the concept of two fractions of normal resting potential maintained by different mechanisms. The higher and more vulnerable is less in soleus than in gastrocnemius. It responds to diresct and indirect tetanus with a decline, the low point of which is similar to that which follows nerve section. Direct tetanization of denervated gastrocnemius muscle affects only the residual of the upper fraction of membrane potential not yet reduced by denervation.

Topical or intravenous administration of ouabain produces a decline of resting potential to the range of 60 mV. Following nerve section only the residual portion of “upper fraction” is vulnerable to ouabain. At no time does administration of ouabain produce a fall of mean resting potential below the level achieved by long term nerve section alone.
The effect of light and light deprivation upon the ultrastructure of the larval mosquito eye. II. The rhabdom
Authors: White Richard H.
Published: June 2005

The surface area of the rhabdom membrane is two to three times greater in mosquito larvae grown in darkness than it is in larvae grown in light. Moreover, light adapted rhabdom microvilli are covered with a surface coat and produce coated vesicles, while the light deprived rhabdom has no coat and does not form coated vesicles. The light adapted microvilli are held together by septate desmosomes; the light deprived microvilli appear to be packed loosely together.

When a light deprived rhabdom is first exposed to light, the membranes of adjacent microvilli rapidly fuse so that the intervillous space is lost. During the next several hours the rhabdom reorganizes to the light adapted state. The intervillous space reopens. The area of the rhabdom membrane diminishes. The coat forms, and coated vesicles are produced in large numbers. This light induced transformation is of interest because of the presumed photoreceptive function of the rhabdom.
Anaerobiosis in a frog, Rana pipiens
Authors: Rose Francis Lewis , Drotman Robert Benjamin
Published: June 2005

Rana pipiens shows an obvious reduction in hepatic, ventricular, and gastrocnemius muscle glycogen concentrations with increasing time in anoxia. Pulmonary repiratory movements drop sharply during the first three minutes of anoxia and virtually cease after 30 minutes. Iodoacetate‐poisoned frogs survive anoxia only 20 minutes; whereas, non‐poisoned animals survive anoxia in excess of two hours. The combined evidence indicates that energy derived from anaerobic processes helps manintain physiological integrity in anurans during conditions of anoxic stress.
Lysosomes in the spleen of the chick embryo. II. Changes during the graft‐versus‐host reaction
Authors: Kimmel Charles B.
Published: June 2005

The graft‐versus‐host reaction (GVHR) was induced in developing chick embryos by inoculation of competent allogeneic cells. The enzyme contents and some properties of lysosomes from the host spleens were examined.

Lysosomal enzymes were found to increase markedly during the GVHR. Changes also were found in the distribution of the enzymes within subcellular fractions obtained by differential centrifugation. A higher proportion of the enzymes was not sedimented with the particulate fractions, and in addition, the proportion of nonlatent enzyme activity in homogenates was significantly increased.

These results could be correlated with those of a cytochemical analysis of acid phosphatase in the spleen during the GVHR. The activity increased markedly and the reaction product was located in small particles, as well as in large vacuoles and inclusion bodies within giant cells. Both granulocytes and mononuclear cells were found with increased amounts of demonstrable enzyme. Many cells showed diffuse staining within their cytoplasm, which suggests that the lysosomes had broken down in these cells.

Similar changes in content and properties of lysosomes have been shown to occur in other systems in which phagocytes are active, or are subjected to stress, as with toxins or antibodies. The present findings are interpreted to reflect an extensive mobilization of host phagocytes in the GVHR, both in terms of their appearance, and of their phagocytic activation.
Adipose tissue of Drosophila melanogaster. III. The effect of the ovary on cell growth and the storage of lipid and glycogen in the adult tissue
Authors: Butterworth F. M. , Bodenstein D.
Published: June 2005

Cytometric analysis was made on the adult adipose tissue of sectioned abdomens of normal and experimentally treated adult Drosophila melanogaster. The adipose cells of two week old males and females are equal in size. The male cells contain 72% glycogen and 7% lipid, whereas the female cells contain 60% glycogen and 23% lipid. The adipose tissue of males containing a mature, transplanted ovary is similar to the female adipose tissue with regard to the cell size and amounts of lipid and glycogen. The adipose cells of castrated females are about 1.4 times larger than those of normal females, but the amount of lipid and glycogen per cell remains somewhat feminine. The adipose cells of genetically sterile, fes, females are about 1.4 times larger than those of normal females, but the amount of lipid and glycogen per cell remains somewhat feminine. The adipose cells of genetically sterile, fes, females are about 1.5 times larger than normal cells and are similar to normal male cells with regard to the proportions of reserve substances. The adipose cells of fes females containing a transplanted, normal ovary shrink to the same size as those of normal flies; and are similar to those of the normal females with respect to amount of glycogen, but are similar to those of normal males with respect to the amount of lipid. The ovary's stimulatory effect on the growth of the larval and repressive effect on the growth of the adult tissue is discussed.
Neuromuscular synapses of a crab motor axon
Authors: Atwood H. L. , Johnston H. S.
Published: June 2005

Neuromuscular transmission of the “fast” motor axon of a crab, Pachygrapsus crassipes, was investigated, using extracellular microeletrodes to record electrical events at individual synaptic regions, and intracellular microelectrodes to record simultaneously the postsynaptic potentials of the muscle fiber. At 1/sec stimulation of the motor axon, the transmitter quantum content per stimulus was estimated at about 2 for many synapses, with relatively slight facilitation at higher frequencies. At some synapses a lower quantum content was measured at 1/sec, and more facilitation was apparent at higher frequencies. Fatigue of transmission with maintained stimulation was rapid.

Observations of time course and amplitude of extracellularly recorded potentials suggested heterogeneity of these events.

Electron micrographs of synapse‐bearing nerve endings showed them to be in clefts or embedded beneath the surface of the muscle fiber. The presynaptic vesicles were usually present at relatively low density, which could account for the rapid fatigue of transmission. Calculated volume distributions of the vesicles did not correspond to amplitude distributions of extracellularly recorded spontaneous potentials; possible reasons for the lack of agreement are discussed.
Correlated physiological and ultrastructural studies on specialised muscles. Ia. Neuromuscular physiology of the levator of the eyestalk of Podophthalmus vigil (Weber)
Authors: Hoyle Graham
Published: June 2005

The eyestalk levator muscle of the crab Podophthalmus vigil has been found to contain two kinds of fiber, pink and white, in separate bundles. Neuromuscular preparations were made of the whole muscle, as well as of white and pink portions separately, and biophysical properties of individual fibers examined. It was found that in extreme cases the fibers have markedly different properties. Some pink fibers were developing tension at normal levels of membrane potential and this was rapidly relaxed by hyperpolarizing pulses. They contracted slowly, but sustained tetani indefinitely. By contrast, some white fibers had quick contraction times, but fatigued extremely rapidly. Evidence was found for four axons: two “fast” excitatory, one “slow” and one inhibitory. It was concluded that a subtle interplay of different neuromuscular properties and different properties of individual muscle fibers, but especially the latter, are both of significance in determining the functioning of the muscle in relation to its role as an organ for minute, precise length changes.