bluuebunny/crossref_metadata_2025 huggingface dataset:
Neural regulation of product discharge from the hedonic glands of the red‐spotted newt, Notopthalmus viridescens
Authors: Pool Thomas B. , Dent James Norman , Kemphues Kenneth
Published: June 2005

The mechanism whereby secretory product is extruded from the lumina of hedonic glands in the red‐spotted newt has been investigated and the chemical nature of that product has been examined. The ultrastructure of the myoepithelium has been studied. Endings of unmyelinated axons, containing both clear and dense‐cored synaptic vesicles, were seen to lie between the myoepithelium and the secretory epithelium, occasionally touching on the myoepithelial cells. Mean luminal diameters of hedonic glands in explants incubated in solutions of acetyl choline decreased by 58% of control values while those of explants incubated in solutions of epinephrine remained the same. Preincubation in the muscarinic blocking agent atropine sulfate, but not in nicotinic blocking agent d‐tubocurarine chloride, prevented the cholinergic response. Two PAS (+) bands were present in polyacrylamide gels prepared from secretions discharged by hedonic glands after treatment of male newts in breeding conformation with pilocarpine HCL and also in gels from skin samples containing mucous glands, but were absent from hedonic secretions of laboratory conditioned males. A smaller but similar band from hedonic glands of breeding females correlated with one of the two. Since hedonic glands, but not mucous glands, from breeding newts of both sexes incorporated 35SO4 into their product, bands from hedonic glands could be distinguished from those of mucous glands in gels. It is concluded that the product of hedonic glands is a sulfated mucin that is discharged in response to cholinergic stimulation of muscarinic receptors in myoepithelial cells.
A scanning electron microscopic comparison of the development of embryonic and regenerating limbs in the axolotl
Authors: Tank Patrick W. , Carlson Bruce M. , Connelly Thomas G.
Published: June 2005

A comparison between the surface features of embryonic limb development and limb regeneration was made in the axolotl. Scanning electron microscopy revealed an overall similarity between embryonic and regenerating limbs. A notable feature was the lack of a morphologically discrete apical epidermal specialization on the surface of any of the limbs. Histological preparations revealed no thickening of the apical epidermis in embryonic limbs. There is a definite thickening of the apical epidermis in regenerating limbs during the stages of dedifferentiation and the early blastemal phases, but the thickening projects into the underlying tissues rather than altering the smooth surface contours of the blastema. Minor differences in epidermal specializations (ciliated cells scattered over the entire body and very irregularly shaped cells with knoblike projections at the tips of digits in embryos) may be attributable to differences in overall activity of the animals at various stages in their life history.
In vitro fertilization of hamster eggs by ejaculated or epididymal spermatozoa in the presence of male accessory secretions
Authors: Tsunoda Y. , Chang M. C.
Published: June 2005

In vitro fertilization of hamster eggs by ejaculated or epididymal spermatozoa in the presence of seminal plasma or male accessory gland secretions was examined. There was no difference in the penetration rates, the time of sperm penetration and the optimal sperm concentration between ejaculated and epididymal spermatozoa. The swelling of the zona pellucida, a high incidence of polyspermy, distortion of the vitellus and the degeneration of eggs were observed after incubation of ejaculated or epididymal spermatozoa in the presence of seminal plasma or accessory gland secretions. Using ejaculated spermatozoa, the fertilization rates of eggs with or without follicular cells were similar but fertilization by epididymal spermatozoa was inhibited by secretion of the seminal vesicle or ventral prostrate gland but not by that of the coagulating gland or the dorsal prostrate.
The alkaline proteases of Argiope and their possible role in web digestion
Authors: Tillinghast E. K. , Kavanagh E. J.
Published: June 2005

The digestive fluid of Argiope was assayed for its proteolytic activity with selected natural and synthetic substrates.

Peak proteolytic activity was observed at pH 7.8. This was coincident with the pH of the digestive fluid.

Elastolytic and weak chymotryptic activities were detected. Limited activity toward collagen was also observed. Activity toward substrates for trypsin, leucine aminopeptidase and carpboxypeptidase A and B was absent.

Evidence demonstrating the in vitro digestion of web fibroin was obtained. The viscid spiral was susceptible to a variety of proteases; the radial fibers to the spider enzyme alone.

Of a series of inhibitors studied, EDTA had the greatest effect upon the spider proteases. This effect was temperature dependent.
Glutamate dehydrogenases from tissues of the ribbed mussel Modiolus demissus: ADP activation and possible physiological significance
Authors: Reiss Paul M. , Pierce Sidney K. , Bishop Stephen H.
Published: June 2005

Glutamate dehydrogenase (E.C. 14.1.3) was localized in the mitochondria from heart, gill, mantle and hepatopancreas of this euryhaline bivalve mollusc. Activity levels were low (0.1‐0.4 μmoles/min/g wet weight) in all tissues when assayed in the glutamate forming direction. Partially purified gill mitochondrial GDH was most active at pH 8.5. The rate in the glutamate deaminating direction was 10‐20% of the rate in the glutamate forming direction. ADP at apparent Ka concentrations of 90 μM (glutamate formation) and 170 μM (glutamate deamination) enhanced GDH activity, 8‐ and 4‐fold respectively. GDH, in vivo, is probably in the activated form and appears to function in glutamate synthesis rather than ammonia formation. However, based on the low activities obtained, the role of GDH in salinity induced amino acid synthesis seems minimal.
In vitro culture of growing mouse oocytes
Authors: Baran Madelyn M. , Bachvarova Rosemary
Published: June 2005

A method is described for in vitro culture of naked growing mouse oocytes for at least four days. Tests for metabolic function indicate that the oocytes increase in volume, accumulate glucose‐6‐phosphate dehydrogenase, and maintain a steady level of 3H‐uridine and 3H‐leucine incorporation.
An analysis of reproductive isolation between Rana magnaocularis and Rana berlandieri forreri (Rana pipiens complex)
Authors: Frost John S. , Bagnara Joseph T.
Published: June 2005

The leopard frogs (Rana pipiens complex) are presently known to include several distinct species, the geographic distributions of which involve numerous sympatries. Very little information has been reported concerning the methods through which such sympatric species maintain their distinctness in suture zones. Therefore, the object of this research was to describe the reproductive nature of the sympatric relationship existing between Rana magnaocularis and Rana berlandieri forreri in western Mexico. Observations were made of seasonal changes in ovarian development and in reproductive behavior between the two species. Genetic compatibility was assessed in numerous interspecific crosses and in backcrosses with laboratory‐produced interspecific hybrids. The breeding period of R. magnaocularis was established as early October through mid‐March and that of R. b. forreri as mid‐March through early September, but limited interspecific overlap in breeding does occur. Females of both species apparently oviposit several times during a single breeding season. Pronounced unidirectional genetic incompatibility was demonstrated in interspecific crosses and most laboratory reared hybrids were found to be sterile. Therefore, breeding season differences and genetic incompatibility (an unusual type) represent major reproductive isolating mechanisms between the two species. Several ethological traits also appear to favor conspecific reproduction, but recent habitat alterations seem to have reduced their effectiveness in the contact zone.
Uptake of amino acids by the mussel Modiolus demissus
Authors: Crowe John H. , Dickson K. A. , Otto J. L. , Colón Rita D. , Farley K. K.
Published: June 2005

Unidirectional and net fluxes of amino acids into isolated gills and intact specimens of the mussel Modiolus demissus were studied. Influx follows Michaelis‐Menten type kinetics, with Kt = 19 and 21 μM, and Vmax = 47 and 107 μmoles/g‐hr for cycloleucine and glycine, respectively. The transport mechanism is specific for neutral amino acids, although other transport systems apparently exist for acidic and basic amino acids. Measurements of primary amines in interstitial waters from the sediments where the animals were found showed that variations in the concentration are found with depth in the sediment, with a maximal concentration of 110 μM. The major primary amines were identified as amino acids. Isolated gills were shown to deplete the medium of the naturally occurring primary amines.
An allelic variant of the sperm‐specific lactate dehydrogenase C4(LDH‐X) isozyme in humans
Authors: Wheat Thomas E. , Goldberg Erwin
Published: June 2005

An unusual pattern of LDH isozymes was observed by gel electrophoresis of an extract of a human testis. This isozyme composition is consistent with an allelic variant ofLdh‐c.
Motility patterns in mouse spermatozoa before and after capacitation
Authors: Fraser Lynn R.
Published: June 2005

The motility patterns of mouse spermatozoa before and after capacitation are described. The latter is very characteristic, with spermatozoa describing a figure‐8 pattern while remaining relatively stationary within a 3‐dimensional space.
Development of the compound eyes of dragonflies (odonata). II. Development of the larval compound eyes
Authors: Sherk Truman E.
Published: June 2005

The development of the compound eye was analyzed by marking individual ommatidia and by studying naturally occurring pigment band patterns.

New ommatidia are added to the eye along its anterior margin. This changes the directions of view of the older ommatidia with the greatest change occurring in the fovea. New ommatidia are added to the fovea medially, and old ones are removed laterally as their interommatidial angles and directions of view in the visual field change.

Over one‐third of the aeshnid ommatidia are foveal during at least one of the early larval instars, and are then used for peripheral vision later in development.

The design of each ommatidium is a compromise so that it is adapted for all stages of development, but sometimes better adapted for one instar than for others. Factors which are balanced for best vision are lens diameter, facet admission function, interommatidial angle, and inclination of the optic axis to the eye surface. Ommatidia are described in terms of these factors throughout their life history, from initial differentiation anteriorly, through passage through the fovea, to their final relatively posterior location.
Induction of supernumerary primordial germ cells by injecting vegetal pole cytoplasm into Xenopus eggs
Authors: Wakahara Masami
Published: June 2005

A fraction, precipitated at 20,000 xG, from vegetal pole cytoplasm of Xenopus laevis eggs was able to induce supernumerary primordial germ cells (PGCs) when injected into subcortical cytoplasm near the vegetal pole of the fertilized egg. The ability to induce supernumerary PGCs was not abolished by digesting the fraction with pronase (Pronase E, 200 μg/ml, at 37° C for 30 min). The possible nature of the “germinal determinant” is discussed.
Triploid and gynogenetic diploid Xenopus laevis
Authors: Tompkins Robert
Published: June 2005

Triploid and gynogenetic diploid Xenopus laevis frogs were produced using pressure to suppress the formation of the second polar body. Five to ten minutes after in vitro insemination, eggs were subjected to six minutes of hydrostatic pressure at 4,800 pounds per square inch. All of the surviving embryos tested were triploid. Application of the same pressure technique to eggs fertilized with ultraviolet irradiated sperm resulted in gynogenetic diploid embryos in every case where the sperm nucleus was inactivated. Triploid and gynogenetic diploid embryos developed normally through the larval period and metamorphosis.
Effects of α‐amanitin on RNA synthesis by mouse embryos in culture
Authors: Levey Irwin L. , Brinster R. L.
Published: June 2005

Investigations were conducted to test the effects of α‐amanitin on RNA synthesis in preimplantation mouse embryos. Exposure of embryos in culture to 1–100 μg/ml α‐amanitin produced a dose‐ and time‐dependent suppression of total RNA synthesis as measured by incorporation of [3H]uridine. Synthesis of polyadenylated RNA in blastocyst‐stage embryos was abolished by α‐amanitin‐treatment at concentrations and exposure times that suppressed total RNA synthesis by less than 15%.

DNA‐dependent RNA polymerase activity was measured in lysates of embryos at several stages of preimplantation development. α‐Amanitin suppressed total polymerase activity assayed under ionic conditions favorable to the detection of RNA polymerase II.

Electrophoretic analyses revealed that preincubation of blastocysts in 100 μg/ml α‐amanitin reduced labelling of cytoplasmic 28S and 18S RNA by inhibition of both synthesis and maturation of nucleolar 45S rRNA‐precursor. This action of α‐amanitin on nucleolar RNA synthesis cannot be correlated with the minimal suppression of nucleolar RNA polymerase activity and suggests that the synthesis and processing of rRNA may be under control of nucleoplasmic gene products.
Analysis of isolated sea urchin nuclei incubated in egg cytosol
Authors: Kunkle Mel , Magun Bruce E. , Longo Frank J.
Published: June 2005

During fertilization the condensed sperm chromatin rapidly disperses and forms the male pronucleus. The possibility exists that substances which are concerned with chromatin dispersion may be present in the egg prior to insemination. To test for the presence of factors that may induce chromatin decondensation within the egg cytoplasm, a cell‐free system was devised in which isolated sperm nuclei were incubated in egg cytosol. Isolated sperm nuclei incubated in egg cytosol underwent nuclear enlargement and spherulation, i.e., increased at least three times that of the original volume of the sperm nucleus. This effect was potentiated, i.e., relatively more protein became associated with sperm nuclei, when sperm nuclei were treated with 0.25 N HCl to extract basic proteins prior to incubation in egg cytosol. Incubation in cytosol from Physarum, transformed NRK cells or Novikoff cells had no effect on the morphology of isolated sperm nuclei. Analysis of the proteins which became associated with acid‐extracted sperm nuclei showed that many had the same apparent molecular weight as those associated with male and female pronuclei. Analysis of egg cytosol proteins also indicated that many polypeptides had an affinity for DNA and the same apparent molecular weight as those associated with male and female pronuclei and zygote nuclei.
Aldehyde oxidase distribution in Drosophila melanogaster mature imaginal discs, histoblasts and rings of imaginal cells
Authors: Kuhn David T. , Cunningham Glenn N.
Published: June 2005

Histochemical staining characteristics for the enzyme aldehyde oxidase are reported for Drosophila melanogaster imaginal discs, histoblasts, and rings of imaginal cells. Aldehyde oxidase activity was observed in all discs except for the eye disc, was found in all imaginal cell groups except in the imaginal cells of the midgut and was found in the histoblasts. Differential aldehyde oxidase staining patterns were observed for the dorsal prothoracic disc, labial disc, antennal disc, for all leg discs (ventral pro‐, meso‐, and metathoracic discs), for the halere disc (dorsal metathoracic disc), for the wing disc (dorsal mesothoracic disc), and for the genital disc. Patterns observed in the various discs are quite repeatable. Enzyme distribution in the mature wing disc may provide an opportunity to visualize developmental compartments.
Experimental studies on hatching behavior in the chick. IV. Evidence for the role of a noradrenergic mechanism
Authors: Pittman Randall , Oppenheim Ronald , Ramakrishna T.
Published: June 2005

In the present experiments we have attempted to determine whether one or more of the biogenic amines are involved in the prehatching and hatching behavior of the chick. Injection of reserpine first induces a depression in ongoing spontaneous motility on day 16 of incubation. Prior to this, reserpine has no apparent effect on embryonic behavior. Reserpine injections on days 17–19 induce a similar behavioral depression that lasts for at least six hours; by 24 hours post‐injection the behavior of reserpine‐treated embryos is comparable to controls. Injection of reserpine on day 20 (post‐pip) delays hatching by about nine hours. Injection of reserpine into the yolk‐sac of eggs prior to incubation also delays hatching by eight to nine hours. It is unlikely that the well‐known car‐diovascular effects of reserpine are involved in the above behavioral results since spinal embryos also exhibit a behavioral depression following reserpine treatment.

Biochemical estimation of norepinephrine (NE) in the brain of reserpinetreated embryos suggests that it is release, not depletion, of the catecholamines that is responsible for the behavioral effects. Additional support for this notion comes from experiments in which 16‐ or 18‐day old embryos were injected with NE, L‐dopa or amphetamine. In each case, a behavioral depression similar to that produced by reserpine resulted.

Clonidine, a NE agonist induces a depression in certain aspects of embryonic behavior (Types 1 and 2), but also selectively enhances a coordinated motor pattern (Type 3 motility) involved in prehatching behavior (tucking). Clonidine first evokes this behavior pattern one to two days prior to its spontaneous appearance on day 16. After pipping on day 19 or 20 clonidine no longer activates Type 3 behavior, even if injected during the actual hatching process (climax). Since the alpha‐adrenergic blocking agent phenoxybenzamine blocks the effect of clonidine on Type 3 tucking behavior, whereas the beta‐adrenergic blocker propranolol does not, we suggest that tucking and the attainment of the hatching position are mediated by an alpha‐adrenergic mechanism in the brain and/or spinal cord. Furthermore, since clonidine affects the Type 3 behavior associated with tucking, but not the somewhat similar coordinated behavior involved in hatching and emergence from the shell (climax), we propose that this later behavior pattern be given a new name, Type 4 motility.
Sexual reproduction in the rotifer Asplanchna girodi: Effects of tocopherol and population density
Authors: Gilbert John J. , Litton James R.
Published: June 2005

Populations containing undetectable levels of tocopherol (< 6.78–20.83 ng per g dry weight rotifer) exhibited normal sexual reproduction, indicating that this species and probably also A. brightwelli and A. sieboldi, do not require tocopherol for male fertility. Thus, the hypothesis that tocopherol is an adaptive signal for mictic‐female production in these latter two species by virtue of its role in male fertility is no longer tenable.

Dietary tocopherol had irregular and only slight, if any, effects on body size and shape, and it did not influence the level of mictic‐female production.

Mictic‐female production was significantly but irregularly affected by population density, at least within the range of 0.0067 to 5 females per ml. No relationship between population density and level of mictic‐female production was observed. The laboratory results are compared with available data on the occurrence of sexuality in a natural population.

None of the 4,537 offspring isolated from parental females in the population density experiments were amphoteric females. Thus, at least under those conditions, this type of female must be extremely rare.

A. girodi differs greatly from A. brightwelli and A. sieboldi regarding responses to tocopherol and the control of sexual reproduction.
Hamster sperm cross react with antiactin
Authors: Talbot Prudence , Kleve Maurice G.
Published: June 2005

Hamster sperm extracts contain a polypeptide which comigrates with muscle actin on polyacrylamide gel electrophoresis. On double diffusion precipitation plates, sperm extracts form a single precipitin band with an antibody to muscle actin (antiactin) and show a reaction of identity with muscle actin. Indirect immunofluorescent microscopy revealed that antiactin binds along the concave margin and equatorial segment in the acrosomal region, in the connecting piece of the neck, and in the principal piece of the tail. These results are evidence that hamster sperm contain actin. The possible significance of these observations in fertilization is considered.
Collagen production by the free‐living nematode Panagrellus silusiae in the presence of the proline analogue L‐azetidine‐2‐carboxylic acid
Authors: Leushner J. , Pasternak J.
Published: June 2005

The effect of the proline analogue, L‐azetidine‐2‐carboxylic acid, on growth and collagen synthesis in the free‐living nematode Panagrellus silusiae was examined. Morph metrically, the worms showed no evidence of an adverse response to the long term presence of azetidine carboxylic acid (20 mM/ml) in the growth media. Incorporation of labelled proline into protein was specifically blocked by the analogue; whereas the uptake of radiolabel led leucine into polypeptides was unaffected. Conversely, the uptake of labelled azetidine carboxylate was antagonized only by proline. The incorporation of labelled analogue into collagen during postembryonic development paralleled the discontinuous pattern of collagen biosynthesis in untreated worms. Cuticular collagens became labelled after incubation with [14C]‐azetidine carboxylate. These results suggest that the analogue is incorporated into collagenous and noncollagenous proteins. To substantiate this point, amino acid analyses of cuticles that were isolated from azetidine carboxylate‐treated worms revealed that the analogue can replace at least 39% of the imino acid residues of the cuticular collagens. Thus, resistance to azetidine carboxylic acid in this organism is not due totally to the metabolic breakdown of the analogue. Although the extent to which noncollagenous proteins incorporate the analogue was not determined directly, it is likely that azetidine carboxylic acid is incorporated into diverse globular proteins without a complete loss of activity of the substituted molecules. Certainly, in the cuticular collagens the analogue can readily replace prolyl residues without any apparent deleterious consequences.
Yolk proteins in the house cricket, Acheta domesticus: Identification, characterization, and effect of ovariectomy upon their synthesis
Authors: Bradley James T. , Edwards John S.
Published: June 2005

Four female‐specific yolk proteins were identified in the hemolymph of adult, ovulating Acheta domesticus through the use of SDS‐polyacrylamide gel electrophoresis. Molecular weights were estimated at 130,000; 97,000; 49,000; and 47,000 daltons, and all four proteins stained PAS‐positive. None of the yolk proteins were detectable in the blood of males or immature females.

The rapid appearance and accumulation of yolk proteins in the blood two to five days after adult ecdysis involves de novo synthesis of the proteins and is unaffected by ovariectomy or hemiovariectomy performed six to eight days prior to ecdysis. Although ovariectomy resulted in the accumulation of yolk proteins in the blood, a comparison of the specific activities of hemolymph proteins in ovariectomized, hemiovariectomized, and sham operated animals following 3H‐leucine injection suggest that the absence of ovarian tissue may lead to a reduction in the net rate of yolk protein synthesis.
Regenerative ability of double‐half and half upper arms in the newt, Notophthalmus viridescens
Authors: Bryant Susan V. , Baca Bruce A.
Published: June 2005

The upper arms of adult newts (Notophthalmus viridescens) were surgically manipulated to create double‐half dorsal, double‐half ventral, double‐half anterior, and double‐half posterior upper arms, and longitudinal half‐dorsal, half‐ventral, half‐anterior, and half‐posterior upper arms. Amputation through the double‐half upper arms usually failed to elicit normal distal regeneration, despite the fact that an apparently normal regeneration blastema was initially formed. Instead, regeneration in these cases was limited to the formation of a variable number of small cartilage elements. On the basis of these results it is concluded that a complete limb circumference is required for distal transformation in newts, in addition to the well‐established requirements for a wound epidermis, adequate innervation and dedifferentiation leading to blastema formation. A model for the sequential generation of new parts of the limb pattern during distal transformation from a complete circumference is presented. This model can also account for the occurrence of normal early stages of regeneration in double‐half upper arms.

Half upper arms which were amputated immediately were shown to develop single, complete regenerates. If amputation of half upper arms was delayed three or more weeks to permit complete wound healing, a supernumerary limb from the lateral wound surface sometimes developed in addition to a complete, single limb from the distal amputation surface.
In vitro analysis of pre‐ and early postimplantation development of lethal yellow (Ay/Ay) mouse embryos
Authors: Johnson Linda L. , Granholm Nels H.
Published: June 2005

Preimplantation embryos from matings between yellow heterozygous (Ay/a) mice were recovered at 56 hours post coitum, cultured for five days, and compared with the development of embryos from three control matings (Ay/a ♀ × a/a ♂, a/a ♀ × Ay/a ♂, a/a ♀ × a/a ♂). Most embryos were at the 8‐cell stage at recovery; however fewer embryos from the experimental cross had developed to the 8‐cell stage than embryos of control matings, indicating a developmental lag of experimental embryos (P < 0.01). The yellow (Ay/a) uterus did not contribute (P = 0.05) to delayed development. Experimental and control embryos were equally capable of successful development in culture to the morula stage with no distinct morphological characteristics identifying the class of Ay/Ay mutants. However, significant differences were observed in the development from morulae to blastocysts; 9.4% (10/106) of the morulae in experimental crosses failed to undergo blastocyst formation as compared with 2.5% (10/398) of morulae in pooled control crosses (P = 0.010–0.025). In the experimental cross 25.0% (24/96) of embryos that developed successfully to the blastocyst stage failed to hatch from the zona pellucida; these are presumed to include the class of lethal yellow homozygotes. Abnormalities seen in cultured embryos consisted primarily of blastomere disintegration, blastomere arrest and exclusion, and embryo fragmentation.
Studies on oocyte maturation of the medaka, Oryzias latipes V. On the structure of steroids that induce maturation in vitro
Authors: Iwamatsu Takashi
Published: June 2005

The response of oocytes within isolated follicles (800–950μ in diameter) to various steroids was examined with the teleost fish, Oryzias latipes. Continuous exposure of oocytes, which were removed from ovarian investments 17 hours before predicted germinal vesicle breakdown (GVBD), to C19‐ or C21‐steroids brought about maturation in vitro but never triggered ovulation. The steroids effective in inducing maturation have in common a C = O (or α‐OH) group at 3C and a β‐OH group at 17C in the C19‐steroids, and a C = 0 (or β‐OH) group at 3C and a C = O (or α‐OH) group at 20C in the C21‐steroids, in addition to an Δ4‐ or Δ5‐unsaturated or 5α‐saturated configuration. The orientation of the hydrogen at 5C seems to be critical in determining the ability of a particular steroid to stimulate oocyte maturation.

Maturation of oocytes in the ovaries of hypophysectomized females was induced by administering progesterone, but the mature oocytes did not subsequently undergo ovulation. Thus the steroid hormone is capable of inducing oocyte maturation but apparently does not participate directly in the ovulation of Oryzias latipes oocytes.
Atrophy of a breast muscle with a single fibre type (M. pectoralis) in fasting willow grouse, Lagopus lagopus (L.)
Authors: Grammeltvedt R.
Published: June 2005

The willow grouse (Lagopus lagopus) are arctic gallinaceous birds with small fat stores and large muscles. In winter, these birds may starve for periods of several days. It was important to know which energy reserves were utilized during periods of starvation. Body composition of female willow grouse and Bantam hens was studied before and after fasting. Grouse have much larger breast muscles than do Bantams, but reproductive organs are larger in the hens. The relative amounts of adipose tissue are about equal in grouse and Bantams. When the birds had lost about 20% of their initial body weight due to fasting, Bantams had lost as much weight from their reproductive organs as from the adipose tissue, with little loss from the muscles. Grouse lost more weight from the pectoralis muscles alone than from the adipose tissue. Since the major component of muscle is protein, the grouse obtain a larger proportion of caloric needs during fasting from protein than do the Bantams.

Grouse breast muscles are dark red, and the pectoralis consists homogeneously of type IIa (oxidative‐glycolytic) fibres, assessed by ATPase and by Sudan Black staining. The supracoracoideus muscle has type II fibres, not resolvable in subtypes. The leg muscle biceps femoris contains the three fibre types I, IIa, and IIb. During fasting, the weight loss of the pectoralis muscle may be accounted for by all fibres losing some material.
Multiple forms of N‐acetyl‐β‐hexosaminidase in developing tadpole fins
Authors: Stuart Elizabeth S. , Everett Gale Beliveau , Fischer Mark S.
Published: June 2005

The degradative enzyme N‐acetyl‐β‐D‐hexosaminidase (Hex) (E.C. 3.2.1.30) has been isolated from livers and tail fins of the amphibian R. catesbeiana. Two amphibian hexosaminidases have been resolved by polyacrylamide gel electrophoresis and quantitated by assay of the separated forms. The electrophoretic mobilities of the hexosaminidases were the same whether isolated from liver or tail tissue. The ratio of hexosaminidase enzymes is constant and independent of developmental stage, tissue source, or method of preparation. It has been concluded that tail resorption and increases in Hex activity are not initiated by changes in the ratio of enzymes and that the net affect of any changes in protein synthesis and degradation must leave the ratio of forms unaltered.
The effect of perfusate oxygen levels on CO2 excretion in the perfused gill
Authors: Haswell M. S. , Perry S. F. , Randall D. J.
Published: June 2005

CO2 excretion across the perfused trout gill was found to fall to levels approaching zero after 20–30 minutes perfusion with perfusates with oxygen tensions at atmospheric levels. When perfusate oxygen levels were lowered by bubbling with nitrogen, CO2 excretion rates remained stable at least 4–6 hours. The ability to maintain a viable perfused gill preparation with respect to CO2 excretion may also be directly applicable to related studies, e.g. gill ion regulation.
Chimaera studies of the origin and formation of the pectoral musculature of the avian embryo
Authors: Beresford Bonnie , Le Lievre Christiane , Rathbone Michel P.
Published: June 2005

Cervical, brachial, and thoracic somites and brachial somatopleure were transplanted from quail into 2‐day chick embryos to determine their contribution to the formation of the pectoralis major muscle. The results show that the musculature of the pectoralis major and pectoralis minor is derived entirely from brachial somites (16–20) while the brachial somatopleure provides much of the connective tissue of these muscles. Migration of somitic cells into the somatopleure appears to begin before the somites are fully formed. The primordium of the pectoralis muscle forms at the base of the wing bud and extends ventro‐caudally into the thoracic area to attach to the sternum.
Removal of amino acid during a single passage of water across the gill of marine mussels
Authors: Wright Stephen H. , Stephens Grover C.
Published: June 2005

The clearance of amino acid during a single passage of inhalent water across the gills of marine mussels was studied. Samples of excurrent water were collected and analyzed for their content of 14C‐labeled amino acids and total primary amines. Comparison with concentrations measured in the ambient medium revealed that mussels are capable of removing large fractions of the amino acid present in inhalent water in a single passage across the gill surfaces. At low rates of pumping, Modiolus demissus was capable of removing 95% of the 14C‐glycine from a 1μ M solution. Efficiency of clearance of amino acid was inversely related to pumping rate; absolute rate of uptake was directly related to pumping rate. Concentration related changes in uptake rate and efficiency of clearance indicated that the effective Kt of glycine uptake by intact Mytilus californianus and Modiolus demissus is between 2 and 5μ M. These values are an order of magnitude lower than published figures for Kt of glycine uptake by preparations of isolated gill tissue from these animals. This discrepancy is probably the result of an increase in the effective thickness of unstirred layers on the surfaces of isolated gills. Net clearance of glycine by M. californianus was observed to occur from concentrations as low as 0.28μ M and, from concentrations of 1μ M and less, an average of 20% of the total primary amine offered initially as glycine was removed during a circuit of inhalent water through the animal. Hence, transepidermal transport processes for amino acids in marine mussels are adapted to function efficiently at substrate concentrations found in their normal environment, and can provide a significant supplemental input of reduced carbon and amino nitrogen for these animals.
Persistence of the nychthemeral rhythm of melatonin secretion in pinealectomized or optic tract‐sectioned trout (Salmo gairdneri)
Authors: Gern William A. , Owens David W. , Ralph Charles L.
Published: June 2005

In a preliminary investigation, what appeared to be melatonin was measured in the plasma of pinealectomized trout using a specific and sensitive radioimmunoassay. Later, following the combined procedures of thin‐layer chromatography and radioimmunoassay, the immunogenic molecule measured in pinealectomized trout plasma was verified as melatonin. After this validation procedure, plasma melatonin titers were assessed using RIA in pinealectomized, sham pinealectomized or intact rainbow trout either at mid‐photophase or mid‐scotophase. Results demonstrated that pinealectomy significantly reduced plasma melatonin measured at mid‐scotophase, compared to the midscotophase values for either the sham‐operated or intact animals. Interestingly, pinealectomized animals continued to show significantly elevated, mid‐scotophase plasma melatonin titers when compared to the mid‐photophase values. The same was true for the sham‐operated and intact groups.

In a second experiment, it was found that severing the optic tract (optictract‐section) did not alter the rhythm of melatonin measured in the plasma. This indicates that the trout pineal may monitor the environmental photoperiod directly, thereby controlling the rhythmic fluctuations in plasma melatonin. Optic tract‐section did cause a significant increase in the mid‐scotophase melatonin titer. This increase may be due to stress caused by sensory deprivation.
Breakdown of the germinal vesicle in bovine oocytes cultivated in vitro
Authors: Motlík J. , Koefoed‐Johnsen H. H. , Fulka J.
Published: June 2005

Breakdown of the germinal vesicle (GV) was studied in bovine follicular oocytes cultivated in vitro. The intact GV of control oocytes did not correspond to the findings in porcine oocytes (GV I). Instead it was characterized by a nuclear membrane and a few chromocenters in finely granular nucleoplasm (GV II). After two and three hours of cultivation, GV III predominated (50% and 64% respectively). Faintly‐staining chromatin and after a longer interval in the form of filaments also appeared round the chromocenters. After four hours, 35.8% of the oocytes were still at stage GV III but the GV of 46.6% of the oocytes already contained filamentous bivalents (GV IV). After five hours, GV IV (59.7%) was typical, with a less distinct nuclear membrane and condensing bivalents. GV breakdown was completed in 30.4% of the oocytes after five hours of cultivation and in 92.5% after six hours.
The mode of action of potassium ions on the leukophores of a freshwater teleost, Oryzias latipes
Authors: Iga Tetsuro
Published: June 2005

Pigment migration within leukophores of Oryzias latipes (a freshwater teleost) is under nervous regulation. Isotonic KC1 induced pigment dispersion in vitro in innervated leukophores, whereas in most of the denervated leukophores the ionic stimulation did not cause the pigment dispersion within the cells. These results show that K ions act through nervous elements on the leukophores to disperse their pigment granules. Local application of the KC1 solution on a scale indicated that the ions act on the nerve terminals situated close to the leukophores to induce the release of a neurotransmitter causing pigment dispersion in leukophores. A few of the leukophores showed a slight pigment dispersion to the ionic stimulation after denervation. It is inferred from this that K ions act also directly on the pigment cells themselves. The pigment‐dispersing response of innervated leukophores induced by the K stimulation was not all‐or‐none type, but increased in a graded manner with the increase in the K concentration in the medium. The threshold concentration of K ions was about 17.3 mM. Full dispersion of the pigment was brought about with a K concentration above 33.3 mM.
Apparent trophoblast giant cell production in vitro by core cells isolated from cultured mouse inner cell masses
Authors: Wiley Lynn M.
Published: June 2005

Mouse ICM's that were isolated from blastocysts by immunosurgery and subsequently cultured for four to five days were tested for their ability to form trophoblast giant cells (TGC's) in vitro. The cores were isolated from such ICM's by a second immunosurgery and cultured for 7 to 14 days. After two days of culture a variable percentage (30%–90%) of the ICM cores produced outgrowths containing cells that resembled those of cultured ectoplacental cone. Then the outgrowths became amitotic and produced vacuolated cells that enlarged to dimensions of 200 × 375 μm with nuclei as large as 53 μm in diameter. The time course of their development from the ICM cores, their morphology and their nuclear diameters suggest that these large cells were TGC's.
Neuronal death in the development of normal and hyperplastic spinal ganglia
Authors: Bibb Harold D.
Published: June 2005

The increase of the peripheral area available for innervation by the ninth spinal ganglion of larval Rana berlandieri was accomplished by unilaterally removing at stage V two (numbers 8 and 10) of the three (numbers 8, 9, and 10) ganglia that normally provide the bulk of the sensory innervation to the hindlimb. Peripheral increase significantly enhanced nerve cell number, and the change in neuronal number with developmental stage was also significant. The increase in nerve cell numbers in affected ganglia of 86% over control values at stage XVI compares favorably with the results of workers using different techniques.

The effect of peripheral increase on normally occurring neuronal degeneration during the development of the hyperplastic condition through early and middle larval stages was determined. While the data show a trend toward the presence of fewer degenerating neurons in peripherally overloaded than in control ganglia through stage X, the differences in the numbers of dying nerve cells were not significant. This fact and other considerations suggest that a mechanism other than or in addition to a reduction in the level of neuronal degeneration must be operative to account for the increase in the number of neurons present in ninth ganglia with expanded peripheries.

Results are discussed in the context of the temporal pattern of the proliferation of cells that differentiate as neurons, the establishment of central‐peripheral connections, and neuronal degeneration.
The role of asters in the localization of the factors that specify the apical tuft and the gut of the nemertine Cerebratulus lacteus
Authors: Freeman Gary
Published: June 2005

The factors that specify the apical tuft of the pilidium larva are located primarily in the vegetal half of the unfertilized egg. Between fertilization and the 8‐cell stage these factors become localized in the animal hemisphere of the embryo. The factors that specify the gut of the pilidium larva are distributed throughout the unfertilized egg. Between fertilization and the four‐cell stage these factors become localized in the vegetal half of the embryo.

The removal of the meiotic apparatus that mediates polar body formation and the treatment of eggs with inhibitors that prevent aster formation, inhibit the localization of the factors which specify the apical tuft and the gut. The induction of asters in unfertilized eggs causes a precocious localization of these factors.
Ontogenetic changes in erythrocytic organic phosphates in the bullfrog, Rana catesbeiana
Authors: Hazard E. Starr , Hutchison Victor H.
Published: June 2005

The metamorphosis of anuran tadpoles includes adjustments to different respiratory media and involves changes in all components of the respiratory system. Increased concentrations of erythrocytic organic phosphates decrease blood oxygen affinity in vertebrates. Nucleoside triphosphates (NTP), 2,3 diphosphoglycerate (DPG), inositol polyphosphate (I‐poly‐P) and total phosphate were measured in different stages of tadpoles, juveniles and adults. The concentrations of NTP, DPG, and I‐poly‐P were, respectively: 4.35, 1.90 and 1.12 μmol ml−1 RBC in tadpoles, and 1.80, 1.10 and 0.393 μmol ml−1 RBC in juveniles and adults. Molar ratios also decreased at metamorphosis: NTP/Hb from 1.83 to 0.49, DPG/Hb from 0.814 to 0.296, and I‐poly‐P/Hb from 0.483 to 0.061. The decrease in NTP occurs simultaneously with the transition from tadpole to adult hemoglobin type. The decrease in DPG parallels the decline in blood pH during metamorphosic climax. Levels of I‐poly‐P were not correlated with developmental changes of the respiratory system. The developmental stages of the decrease in red cell organic phosphate concentrations coincide with the suite of adaptive adjustments which lead to aerial respiration in metamorphosing bullfrogs.
The fine structure of developing cartilage in the chick embryo
Authors: Olson Mark D. , Low Frank N.
Published: June 2005

The fine structure of developing cartilage is described in the area of the future vertebral bodies in the cervical region of chick embryos. Incubation ages range from 36 hours, when the schlerotome….
Wing pattern formation in Lepidoptera: A model
Authors: Nijhout H. Frederik
Published: June 2005

A formal model is presented that demonstrates how the color patterns of the wings of butterflies and moths can be analysed in terms of current concepts of pattern formation. A review of pertinent literature on this little‐known developmental system is provided. Crucial to the understanding of color pattern formation in lepidopteran wings is the realization that the wing pattern is a mosaic. The pattern in each wing cell (i.e., the area bordered by wing veins) is determined independently from the pattern in other cells. Within a cell, pigments are deposited in a definite relation to a central focus. A focus always lies on the cell midline and is often visible as a small pigmented dot. In the simplest condition the color pattern is laid down around a focus as a system of perfect concentric circles (eyespots). More often these circles are considerably distorted and have an axis of bilateral symmetry that parallels the wing veins. The nature and extent of these distortions from circularity account, to a large degree, for the species‐specific character of the wing pattern. The determination of such patterns is most readily explained if it is assumed that a focus represents the reference point with respect to which positional information (for pigment deposition) is specified. Circular patterns are thus obtained if all points equidistant from a focus undergo identical differentiation. Deviations from circularity of the pattern around a focus indicate that either the specification or interpretation of positional information is not the same in all areas around a focus. This phenomenon is most conveniently described as an “interpretation landscape”: a gradient system whose value at any point in a morphogenetic field is a measure of how positional information is to be interpreted at that location. Examples are provided of how species‐specific wing patterns can be generated by modest alterations in the shape of the interpretation landscape. As a rule the field of a focus is limited by the margins of the wing cell in which it is centered except in cases where no focus is present in an adjacent cell. Under those circumstances one focus can determine the pattern in several adjoining wing cells.
Renal alterations induced by osmotic stress and metabolic acidosis in Xenopus laevis
Authors: Stetson David L.
Published: June 2005

Xenopus has unusual flask cells within the intermediate segment of the renal nephron. These cells respond to osmotic stress by losing the glycosaminoglycan (GAG) contents from their central cavities. Because of this it has been argued that flask cells participate in osmoregulation. The present work was designed to investigate changes in morphology of the flask cells and to determine whether such changes could be related to simultaneous changes in nitrogen excretion rather than osmotic stress.

In animals exposed to 21 days of osmotic stress, total nitrogen excretion doubled relative to controls and urea comprised 85% of waste nitrogen. The activity of phosphate dependent glutaminase (PDG), a renal ammonia‐producing enzyme, did not decrease even though ammonia excretion decreased by more than 50% in experimental animals. Structurally, flask cells had shrunken and contained little GAG. The average number of distended flask cells within profiles of intermediate segments dropped from about 2 in control animals to 0.60 in animals stressed for 14 days.

Acidosis was induced in Xenopus by injecting a single dose of 2.5 mM HCl per kg body weight. In these animals, ammonia excretion increased 160% over controls and PDG activity increased 30%. The number of flask cells in intermediate segment profiles increased from 2.02 in controls to 4.16 in experimental animals.

These results demonstrate that the number of distended flask cells and their morphology are altered by conditions which change patterns of nitrogen excretion; therefore, the flask cells may be directly involved with ammonia excretion.