bluuebunny/crossref_metadata_2025 huggingface dataset:
The progesterone receptor‐like properies of Xenopus laevis oocyte melanosomes are probably due to eumelanin
Authors: Coffman Gary K. , Keem Kirsten , Smith L. Dennis
Published: June 2005

The binding of progesterone to the melanosomes of the Xenopus laevis oocyte was examined. Based upon the similarities between the eumelanin complex, which is prepared by stripping melanosomes of their proteins, and synthetic melanin in regard to their association with progesterone and other steroids, the data strongly suggest that eumelanin rather than a protein is responsible for the receptor‐like properties of the melanosomes.
Environmental influences on hormonally induced spermiation of the bullfrog, Rana catesbeiana
Authors: Easley Kirk A. , Culley Dudley D. , Horseman Nelson D. , Penkala Joseph E.
Published: June 2005

Frog pituitaries, human chorionic gonadotropin (HCG), luteinizing hormone (LH), follicle stimulating hormone (FSH) and gonadotropinreleasing hormone (LH/FSH‐RH) were tested to determine their effectiveness in eliciting the spermiation response in laboratory‐reared male bullfrogs (Rana catesbeiana). LH/FSH‐RH gave the highest percentage of positive responses and the most rapid responses. Sperm acquired by cloacal sampling after LH/FSH‐RH injections were fertile.

Day length (14L:10D; 8L:16D, 25°) had no measurable effect on reproductive condition, growth or sensitivity to injections of LH/FSH‐RH. Spermiation response to LH/FSH‐RH was depressed at low temperatures (15°, 20° C) and testicular recrudescence appeared to be inhibited at warm temperature (30°C). Optimum spermiation responses were obtained at 25°C.

A marked daily rhythm (unimodal) of spermiation response to LH/FSH‐RH was observable. Injections given one hour before the onset and offset of a 12L:12D photoperiod (25°C) were respectively the most and least effective in stimulating spermiation. The peak and trough of the rhythm were attributed to changes in pituitary sensitivity to LH/FSH‐RH and not changes in testicular sensitivity to LH.

Age and size of bullfrogs utilized in these tests had no effect on spermiation response.
Binding and redistribution of surface membrane receptors for concanavalin A on oyster hemocytes
Authors: Yoshino Timothy P. , Renwrantz Lothar R. , Cheng Thomas C.
Published: June 2005

The binding and redistribution of Con A surface membrane determinants was investigated in two Crassostrea virginica hemocyte subpopulations (designated LS and SS) by employing a direct Con A‐peroxidase coupling method in conjunction with light and electron microscopical cytochemistry. At 4°C small, adherent hemocytes exposed to Con A and horseradish peroxidase (HPO) produced a uniform staining pattern on hemocyte surface membranes. Polar redistribution or capping of Con A receptors was observed in 22.2% of LS and 11.0% of SS hemocytes when the incubating temperature was increased from 4 to 21°C. Receptor patching, observed with equal frequency (∼15%) in both cell subpopulations, also exhibited a temperature dependency. Capped hemocytes were readily identified by the polar concentration of darkstaining HPO reaction product along the marginal surface of each cell. Receptor patching was observed as multiple aggregates of reaction staining on blood cell surface membranes. Cap formation in SS hemocytes was inhibited by sodium azide (−N3) at each concentration of inhibitor tested. LS hemocyte capping was inhibited only at the highest −N3 concentration (5 × 10−2 M). Cells of both subpopulations were unable to completely reverse the effects of −N3 poisoning following inhibitor removal.
Age‐related changes in ovarian responsiveness to gonadotropins in normal and neonatally estrogenized mice
Authors: Mori Takao
Published: June 2005

Young ovariectomized mice were transplanted with ovaries obtained from either neonatally estrogenized or normal mice at different ages. Cyclic estrus ensued in 71% of the mice receiving ovarian grafts from 3‐month‐old normal donors. If donors were 12, 15 and 20 months old, cyclic estrus took place in 15, 10 and 0% of the recipients, respectively. By contrast, after transplantation of ovaries from neonatally estrogenized mice, aged 3, 12 or 15 months, cyclic estrus occurred in about 42–48% of the recipients regardless of the age of donors. Three of 17 recipients receiving ovarian grafts from 20‐month‐old neonatally estrogenized donors still showed cyclic estrus. Therefore, in neonatally estrogenized mice, decline of ovarian responsiveness to circulating gonadotropins appears to be inhibited or delayed until at least 15 months of age.
Behavioral effects of castration and testosterone propionate replacement combined with ACTH in the male domestic duck (Anas platyrhynchos L.)
Authors: Deviche Pierre
Published: June 2005

Twenty‐one adult male ducks were bilaterally castrated, then injected as follows for 17 consecutive days: testosterone propionate (TP; N = 6; 5 mg/day/bird) + ACTH (20 IU/day/bird); TP + saline (N = 6); oil + ACTH (N = 5); oil + saline (N = 4).

The birds were repeatedly observed under standardized conditions, before castration as well as during the hormonal treatments. Their behavioral performances were compared to those recorded in a sham‐operated group (N = 6).

Castration resulted in a decrease of most social activities – aggressive and sexual behavior, social displays – and of the general level of activity.

TP administration resulted in a complete reversal of these effects. ACTH treatment did not by itself induce any detectable change.

The results are discussed in view of the present knowledge of the endocrine regulation of behavior in ducks. Evidence is also provided that individual differences in behavioral performances cannot be directly related to differences in androgen plasma levels.
Developmental changes in the pyruvate kinase isozymes of coho salmon
Authors: Guderley Helga E. , Cardenas Janet M.
Published: June 2005

Pyruvate kinase exists as two major isozymes in coho salmon. As in mammals and birds, one form is present in the early embryo and maintains a wide tissue distribution in adults. This salmonid type K shows anodal migration during electrophoresis at pH 7.5. The appearance of the second major pyruvate kinase isozyme coincides with the appearance of functional musculature in the developing embryos. In adult animals this second form is the only pyruvate kinase in muscle. Brain, kidney, liver and gill contain primarily the type K pyruvate kinase while heart contains both major forms along with three intermediate forms which presumably constitute a hybrid set. Since there is no additional isozyme restricted to gluconeogenic tissues, we conclude that a type L isozyme has not developed in these animals.

The two major isozymes are immunologically distinct. Both forms are subject to fructose 1,6‐bisphosphate activation of phosphoenolpyruvate binding, but the magnitude of the effect is small. The affinities for phosphoenolpyruvate are similar, but salmon type K has hyperbolic saturation curves with this substrate and type M has sigmoidal saturation curves. While the immunological data indicates considerable divergence in structure, the kinetic parameters of the two forms have remained relatively similar.
Aerobic and anaerobic metabolism during activity in small rodents
Authors: Ruben John A. , Battalia David E.
Published: June 2005

Analysis of oxygen consumption and lactic acid formation during five minutes of maximal activity by the rodents Microtus montanus (Cricetidae) and Dipodomys merriami (Heteromyidae) indicates that: (1) anaerobiosis provides approximately 10% of total energy utilized during the 5‐minute activity period; (2) anaerobiosis may account for as much as one‐third of total energy utilized during the first 30 seconds of activity. In addition, these data indicate at least one species of lizard may be capable of a higher total rate of metabolism during “burst” activity than are the rodents investigated here.
A revision of the inhibitory innervation pattern of the thoracic limbs of crayfish and lobster
Authors: Hill Russell H. , Lang Fred
Published: June 2005

ABSTRACT The inhibitory innervation to the muscles of the claws and walking legs of lobsters and crayfish was investigated. In contrast to previous studies, we find that in these limbs the closer muscle shares an inhibitory axon with the bender and extensor muscles, but not with the stretcher muscle. These findings may help to explain some of the anomalous results reported by others.
Distribution of phenylalanine hydroxylase (EC 1.14.3.1) in liver and kidney of vertebrates
Authors: Hsieh Monica C. , Berry Helen K.
Published: June 2005

The range of phenylalanine hydroxylase activity was determined by measuring the conversion of radioactive phenylalanine to tyrosine in liver and kidney of various vertebrates. Rodents (rats, mouse, gerbil, hamster and guinea pig) were found to have the highest liver phenylalanine hydroxylase activity among all animals studied. They are also the only species that possessed a significant kidney phenylalanine hydroxylase activity which was about 25% of that found in the liver of the same animal.

The synthetic dimethyl‐tetrahydro‐pteridine, used as a cofactor for the enzyme assay in most studies, catalyzed non‐enzymatic hydroxylation of phenylalanine to tyrosine. Inclusion of boiled‐blank and strict control of timing between incubation and product measurement were essential precautions to minimize erroneous results from substrate contamination and non‐enzymatic hydroxylation.
Effects of accelerating stimulation on different indices of development in Japanese quail embryos
Authors: Vince Margaret A.
Published: June 2005

Effects of continuous accelerating stimulation on the timing, duration and rate of occurrence of different indices of development in Japanese quail embryos were examined. Indices used were: the onset of breathing and hatching, also pipping, clicking, vocalisation, membrane penetration, yolk sac withdrawal and lung aeration. Results showed that embryos stimulated by clicks began breathing about nine hours in advance of unstimulated controls and hatched about 23 hours in advance. All other indices occurred early in comparison with controls but not all occurred at the same accelerated rate and some having begun early, proceeded at the same rate as controls then were completed rapidly just before hatching. Developmental problems are discussed in the light of these results and it is suggested that continuous accelerating stimulation affects development in two main stages.
Epidermal‐dermal recombinations with embryonic naked and normal back skin of Gallus domesticus
Authors: Juran Marlane R.
Published: June 2005

Birds exhibiting a varying featherless condition resulting from the recessive, sex‐linked gene naked (n) were used to investigate whether the gene altered the dermis or the epidermis. By splitting 7‐day normal and naked skin into its dermal and epidermal components, and heterotypically recombining and growing it in chambers on the chorio‐allantoic membrane (CAM), it was found that the epidermis of the naked birds is the site of mutant gene action. A histological study of developing normal and naked skin was done and the structure of the naked feather is elucidated.
A factor necessary for normal morphogenetic function of Anuran endoderm
Authors: Ansevin Krystyna D. , Williams Barbara J.
Published: June 2005

Cytoplasmic preparations obtained from late blastulae and early gastrulae of normal R. pipiens eggs contain factors which induce delayed lethal effects when injected into normal eggs at the beginning of cleavage. The same preparations can rescue some defective eggs which occur spontaneously (NS eggs), or are produced experimentally (ES eggs), by relieving the specific developmental syndrome displayed by either type of egg. The syndrome involves abnormal endoderm in which cytolysis is time‐programmed. The lethal factors as well as the rescue factors are absent in the normal egg cytoplasm prior to the late blastula stage.
The distribution of sorbitol dehydrogenase in embryonic and adult chicken tissues
Authors: Defabro Sofía P. , Bishop David W. , Goldemberg Adriana Lía
Published: June 2005

Sorbitol dehydrogenase activity (SDH) has been determined in various organs of embryonic and adult chickens. SDH is present in 24‐hour embryos, and its activity continues to rise during the next 48 hours. During embryonic development and after hatching, regional differences in SDH activity are demonstrable in the organs of the animal. These differences concern both level of enzyme activity and temporal changes with development. No correlation could be established between enzymatic activity and the fructose concentration of the organs studied.
Chromatographic fractionation of aggregation and sex pheromones of Nippostrongylus brasiliensis (Nematoda)
Authors: Bone Leon W. , Gaston Lyle K. , Hammock Bruce D. , Shorey H. H.
Published: June 2005

Gel filtration with Sephadex G‐25 or Bio‐Gel P‐2 of homogenates of the sexes of the zooparasitic nematode Nippostrongylus brasiliensis revealed two fractions with pheromonal activity. One active fraction with a suggested molecular weight over 500 was found in aqueous extracts of both helminth sexes and was attractive to both sexes by in vitro bioassay. A second region of pheromone activity was found in only female Nippostrongylus and was attractive to only male helminths. A molecular weight under 400 is proposed for this region. Additionally, a third region that represented ionic weights was present in both sexes, but attracted only female worms. These results indicated that helminth to helminth attraction is present at both species and sexual levels of recognition.
Anhydrobiosis in nematodes: Inhibition of the browning reaction of reducing sugars with dry proteins
Authors: Loomis Stephen H. , O'dell Steven J. , Crowe John H.
Published: June 2005

Decay of primary amines associated with proteins of anhydrobiotic and lyophilized, fresh nematodes (Aphelenchus avenae) occurs more readily in the lyophilized, fresh worms than in the anhydrobiotic ones. Addition of glucose accelerates the rate of decay, while addition of trehalose along with the glucose inhibits the effect of the glucose. Similar results were obtained with bovine serum albumin stored in the presence of glucose, glucose and rehalose, or trehalose. The data are interpreted to mean that not only does trehalose not participate in a browning reaction with dry proteins, but that it also inhibits browning reactions between dry proteins and reducing sugars.
The gill arch of the mullet, Mugil cephalus. I. Surface ultrastructure
Authors: Hossler Fred E. , Ruby John R. , McIlwain Thomas D.
Published: June 2005

The surface ultrastructure of the gill arches of the mullet, Mugil cephalus, was studied by scanning electron microscopy. Each gill arch supports two rows of gill filaments which extend posterolaterally, and two rows of gill rakers which extend anteromedially. Secondary lamellae (respiratory lamellae) extend from both lateral surfaces of each filament, and numerous secondary projections, either spiny or smooth, extend from the anteromedial aspect of each raker. Raker morphology varies somewhat from one gill arch to the next and from the dorsal to ventral aspects of the same gill arch. All surfaces of the gill arch except the respiratory lamellae and portions of the rakers are covered with a mosaic of ridged epithelial cells. These cells measure 3‐10 μ in diameter, and possess concentrically arranged surface ridges which measure 0.1–0.15 μ in width. In contrast, the respiratory lamellae and the anteromedial surface ridges. Numerous pores, having rounded cellular extensions projecting from their ineriors, are irregularly located between the ridged epithelial cells. Pores are common on the apposing surfaces of the rows of gill filaments and at the bases of the respiratory lamellae, but are rare or absent on other surfaces of the filament. Because the pores likely represent entrances to apical crypts of chloride cells, scanning electron microscopy may be useful in monitoring changes in the number and distribution of chloride cells in gill filaments of euryhaline fish during adaptation to various salinities.
Application of malachite green‐containing glutaraldehyde as a fixative for electron microscopy of xanthophores in the medaka, a Teleostean Fish
Authors: Takeuchi Ikuo K.
Published: June 2005

In xanthophores of the medaka, Oryzias latipes, numerous electron‐dense granules of varying sizes ranging from 0.2 um to 0.5 um are encountered after fixation of tissues by a malachite green‐containing glutaraldehyde. These granules are never observable in tissues prepared by conventional glutaraldehyde fixation, and they are considered to be lipid in nature and contain carotenoid pigments.
Microsphere studies of Bullfrog central vascular shunts during diving and breathing in air
Authors: Meyers R. S. , Moalli R. , Jackson D. C. , Millard R. W.
Published: June 2005

Bidirectional central vascular shunts were measured during diving and breathing in air in unanesthetized bullfrogs by using pulmonary trapping of 38μ mean diameter radionuclide‐labelled microspheres. Six animals studied during diving exhibited a strong overall right‐to‐left shunting pattern comprised of both a predominant (68% mean) right‐to‐left shunt and a weak (23%) left‐to‐right countershunt. Five animals with access to air showed a variety of distribution patterns, including predominant shunts in the left‐to‐right (1 animal) and right‐to‐left (1 animal) directions, nearly complete mixing (2 animals) and separation of systemic and pulmonary venous returns (1 animal).
Morphological studies on cardiac lethal mutant salamander hearts in organ cultures
Authors: Hill Craig S. , Lemanski Larry F.
Published: June 2005

Recessive mutant gene c in Ambystoma mexicanum results in an absence of embryonic heart function. When mutant hearts are transplanted into normal embryos, the defect is corrected and the mutant hearts beat. In reciprocal transplants normal hearts do not beat. These experiments suggest that there is either a lack of induction from surrounding tissues or an inhibitory influence of some kind. We undertook the present study to determine whether the influence in vivo might be an inhibitory one which could be corrected simply by removing the heart from the embryo and growing it in culture. Hearts from normal and mutant siblings from stages 35–40 were explanted into hangingdrop cultures in Holtfreter's solution. Normal hearts continued to beat strongly while mutant hearts failed to beat. After five to seven days, cultured hearts were compared to in vivo hearts at the same period of development using light and electron microscopy. The myocardium of normal hearts is composed of highly differentiated muscle cells with numerous well‐organized myofibrils. The mutant myocardial cells contain a few filaments and an occasional Z body, however, sarcomere organization is not apparent. In general, no major differences in morphology or function could be found between the cultured and in vivo hearts at the same period of development. Thus, the cultures closely mimick the in vivo situation and present evidence against an inhibitory process causing the defect.
Development and survival of haploids of the Mexican axolotl, Ambystoma mexicanum
Authors: Hronowski Lucjan , Gillespie Laura L. , Armstrong John B.
Published: June 2005

Gynogenetic haploids of the Mexican axolotl, Ambystoma mexicanum, were produced by artificial insemination of eggs with ultraviolet‐irradiated sperm. Initially, haploids developed more rapidly than control diploids, and had twice the number of cells by 12 hours. Thereafter, development was slower, but haploids maintained a 2:1 ratio of cell number at the same morphological stage. In both haploids and diploids, division was rapid up to gastrulation, at which point the rate decreased 40‐ to 50‐fold. Prehatching mortality of haploids was greater than that of control diploids, but for both, the pattern appeared related to that of cell division; embryonic mortality was highest in the first few days, and then decreased substantially. Though nearly 50% of the haploids did survive to hatching, most failed to feed, and those that did were generally abnormal in appearance, and did not survive to maturity. The results suggest that prehatching mortality can be blamed neither on the expression of deleterious recessives nor on a reduced nucleocytoplasmic ratio.
Circadian wheel‐running behavior in the isopod, Armadillidium vulgare
Authors: Smith John T. F. , Larimer James L.
Published: June 2005

Pillbugs given access to both a darkened moist refuge and a styrofoam running wheel engaged in locomotor activity on the running wheel a portion of each night. The animals expressed a circadian rhythm of locomotor behavior in constant conditions. The evidence suggests that the locomotor activity rhythms originate endogenously. The circadian behavior of woodlice as well as the adaptive or ecological significance of biological clocks in terrestrial isopods is discussed.
Specificity of inhibition by steroids of porcine oocyte maturation in vitro
Authors: Richter Joel D. , McGaughey Robert W.
Published: June 2005

In order to examine the influence of several steroids on the process of oocyte maturation, denuded (adherent cumulus granulosa cells mechanically removed) and intact (cumulus granulosa cells left attached) porcine oocytes were cultured in the presence or absence of estradiol‐17β, estradiol‐17α, testosterone, cortisol, progesterone, or the nonsteroidal estrogen diethyl stilbestrol (all at 10 μg/ml) in defined medium that contained either BSA or dextran. Estradiol‐17β was the only steroid to exert a significant inhibitory effect on the maturation of denuded oocytes, and did so only in BSA supplemented medium. The inhibition was reversible in that oocytes, cultured in steroid‐free medium after initial culture in estradiol‐17β medium, resumed meiotic maturation. Oocytes took up 3H‐estradiol‐17β in both media, although less radiolabel entered oocytes in BSA supplemented medium. The majority of label in the oocytes, when cultured with either medium, was not displaced by excess radioinert estradiol‐17β or progesterone, nor were the oocytes saturated even when cultured in 10−6 M estradiol‐17β. Autoradiography of sectioned oocytes after culture in 3H‐estradiol‐17β has shown that there was no selective accumulation of silver grains over the germinal vesicle as was the case with granulosa cell nuclei. This observation suggests that estradiol‐17β may not act at the level of the oocyte nucleus.
Delayed reproductive regression in male hamsters bearing intrarenal pituitary homografts and kept under natural winter photoperiods
Authors: Reiter Russel J. , Ferguson Bonnie N.
Published: June 2005

The testes and accessory sex organs of adult male hamsters regressed to an infantile state when the animals were maintained under natural photoperiodic and temperature conditions beginning November 13. The atrophy was evident after both five and ten weeks exposure to these conditions. Either one or two prolactin‐secreting pituitary grafts placed under the kidney capsule greatly delayed the testicular and accessory organ regression. Animals bearing pituitary grafts also had higher circulating levels of immunoreactive prolactin while plasma luteinizing hormone values were similar in all groups of hamsters.
Increase in conductance to water vapor during incubation in eggs of two avian species
Authors: Carey Cynthia
Published: June 2005

In contrast to previously published observations of constant daily water loss during incubation in some large, precocial eggs, daily rates of water loss increase approximately 42% between days 1–4 in redwinged blackbird eggs and conductance to water vapor increases 47 and 48% during the early stages of incubation in red‐winged blackbird and robin eggs, respectively. Therefore, the age of eggs is one factor which must be considered when conductance of eggs of conspecific populations is compared between habitats or over altitudinal gradients.
Purine production during fasting in the slug, Limax flavus linne
Authors: Horne Francis B. , Beck Sharon
Published: June 2005

The slug, Limax flavus, reduces hepatopancreatic rates of purine synthesis during fasting.

Total body purines decreased during fasting from 661 μg/g wet wt to 384 μg/g wet wt. Slugs fed ad libitum contained 1.5, 2.4 and 2.5 as much uric acid, xanthine and guanine as did slugs fasted for 20 to 23 days. Adenine and hypo‐xanthine were detected inconsistently in the active feeding slugs, where values ranged from 0‐78 μg/g wet wt and 0‐94 μ/g wet wt, respectively (14C glycine‐incorporation).

Rates of purine synthesis also decreased with fasting. In active feeding slugs, synthetic rates for adenine, guanine, hypoxanthine, uric acid and xanthine were 17, 36, 14, 138 and 49 nmole/g/d, while in the fasting animals the rates were 2, 9, 0, 81 and 20 nmole/g/d, respectively. The rate of purine production dropped by 56% or a factor of 2.27, which was similar to the decrease in body purines (42% or 1.72 with fasting).

Slug hepatopancreatic phosphoribosylpyrophosphate amidotransferase (E.C.2.4.2.14), the enzyme of the first committed step of purine synthesis de novo, was compared with the domesticated chicken liver enzyme. When assayed under the same conditions, both enzymes had similar activities, but differed in that substrate (glutamine) versus velocity plots were sigmoidal for the slug enzyme and hyperbolic for the chicken enzyme. Estimated substrate affinities were Km = 19.0 mM and Km = 2.0 mM for the slug and the chicken enzymes respectively.
1‐Methyladenine induction of oocyte (starfish) maturation: Inhibition by procaine and its pH dependency
Authors: Cloud J. G. , Schuetz A. W.
Published: June 2005

Fully grown oocytes of starfish (Asterias forbesi) are normally arrested in the dictyate stage of meiosis within the ovary. Reinitiation of meiotic maturation in these oocytes appears to be induced as a result of the interaction of 1‐methyladenine (1‐MA) with the oocyte surface. The objective of this investigation was to determine whether procaine, a membrane active pharmacological agent, alters the ability of 1‐MA to induce oocyte maturation. Procaine (0–2 mM) at pH 8.3 inhibited 1‐MA induced maturation in a dose dependent manner; inhibition of maturation was seen only when the oocytes were incubated with procaine prior to the addition of 1‐MA. The inhibitory effect of procaine was reversible as indicated by the observation that oocytes which failed to mature in seawater containing 1‐MA (1 μg/ml) and 1 or 2 mM procaine at pH 8.3 subsequently underwent maturation after washing the procaine out and incubation with 1‐MA. Procaine inhibition of oocyte maturation was dependent on pH of the seawater; this inhibitory action of procaine decreased as pH decreased from 8.5–6.0. In seawater at pH 7, procaine (2 mM) reduced the biological activity of 1‐MA to approximately 0.1 of its potency; at pH 8.3 procaine completely blocked 1‐MA induction of oocyte maturation. The amount of 1‐MA bound or incorporated into the oocytes, as measured by the radioactivity in oocytes following incubation in seawater containing 3H‐1 methyladenine, is reduced to 10% of control by 2.0 mM procaine. Taken together, the data suggests that procaine inhibits oocyte maturation by limiting the amount of hormone on or in the oocyte and that this effect is pH dependent.
Scanning electron microscopy of the surface of normal and implantation‐delayed mouse blastocysts during development in vitro
Authors: Shalgi Ruth , Sherman Michael I.
Published: June 2005

Mouse blastocysts undergo developmental steps in culture analogous to those occurring during implantation in utero. We examined cultured blastocysts by scanning electron microscopy (SEM) as they passed through these stages. From the time of hatching to the acquisition of adhesiveness, most blastocysts were exhanded, with flattened cells possessing relatively small numbers of microvilli, centrally raised areas (presumably reflecting the location of the nuclei) and intercellular ridges often possessing microvilli. At, or shortly before, the trophoblast outgrowth stage, blastocysts appeared to contract; the cells bulged noticeably, microvilli covered the entire surface of most cells and intercellular ridges were no longer observable.

Blastocysts removed from uteri on the seventh day of ovariectomy delay possessed a variety of morphologies and shapes. The blastocoel was frequently collapsed and cell outlines were difficult to discern. These blastocysts were initially adhesive in vitro, but subsequently disengaged from the substratum before becoming permanently adherent several hours later. During the initial phase of adhesiveness, blastocysts were elongated and had prominent intercellular ridges, particularly in the equatorial region. Detached blastocysts contained bulging cells with contours which obscured the intercellular ridges. Surface ultrastructure during subsequent phases resembled non‐delayed blastocysts during attachment and outgrowth.

On the basis of our studies, we propose that intercellular ridges play some role in blastocyst adhesiveness. However, we must conclude that there are other factors involved in the acquisition of adhesiveness by the blastocyst which are at least equally important but of a nature too subtle to be identified by our SEM analyses. Insofar as delayed blastocysts are concerned, we find that, within limits, the surface alterations that take place when blastocysts are activated in culture mirror those observed following reversal of delay in vivo by administration of hormones. Since delayed blastocysts placed in saline also undergo morphological changes resembling those seen at the onset of activation in utero, we suggest that reversal of implantation delay requires initially neither direct contact with steroid or macromolecular inducers nor an exogenous supply of metabolites.
Induction of triploid and gynogenetic diploid axolotls (Ambystoma mexicanum) by hydrostatic pressure
Authors: Gillespie Laura L. , Armstrong John B.
Published: June 2005

Hydrostatic pressure of 10,000 psi, applied 60 minutes from oviposition, for eight minutes, was used to suppress the formation of the second polar body in fertilized axolotl eggs. When this procedure was used on naturally fertilized eggs, triploid axolotls were produced with 97% efficiency. Artificial insemination with ultraviolet irradiation inactivated sperm in combination with this procedure yielded gynogenetic diploids with 92% efficiency. Survival was variable in both sets of experiments and ranged from 64% to 72%.
Prevention of in vitro fertilization of canine oocytes by anti‐ovary antisera: A potential approach to fertility control in the bitch
Authors: Mahi Cherrie A. , Yanagimachi Ryuzo
Published: June 2005

Antisera raised against canine ovaries were found to induce light scattering of the surface of the egg zona pellucida even when diluted 10,000 times, and to delay digestion of the zona by pronase. High concentrations of antiserum were required, however, to inhibit in vitro fertilization of the oocytes. Absorption of the antisera with canine ovaries removed these effects, whereas absorption with liver, uterus and serum did not. These results demonstrate the antigenicity of the canine ovary and suggest the plausibility of an anti‐zona pellucida vaccine for birth control in the bitch.
Aminoethylphosphonic acid (AEP) containing glycoproteins in metridium senile: 14C‐AEP incorporation and electron probe microanalyses
Authors: Dearlove George E. , Bishop Stephen H.
Published: June 2005

Metridium senile were incubated in sea water containing 14C‐aminoethylphosphonic acid and 35S‐SO4. Incorporation into protein and lipid was rapid with 14C‐AEP and below detectable limits with 35S‐SO4. Ultrastructural‐electron microprobe x‐ray analysis of the mucus granules in the mid‐body epidermal cells confirms a high concentration of phosphorus and the absence of sulfur. These experiments confirm previous histochemical and biochemical studies (Bunde et al., '78) and demonstrate the capacity for AEP‐glycoprotein biosynthesis by M. senile.
Behavioral thermoregulation in lizards: A circadian rhythm
Authors: Cowgell John , Underwood Herbert
Published: June 2005

Body temperatures of individually housed Sceloporus occidentalis were monitored continuously while the animals moved freely over a thermal gradient during several daily light‐dark cycles and a subsequent period of constant darkness. These self‐selected body temperatures display a distinct daily pattern, a pattern which is maintained (with an altered cycle length) during constant darkness.
Prostaglandin E2 inhibition of sodium transport in the freshwater mussel
Authors: Graves Sidney Yeider , Dietz Thomas H.
Published: June 2005

Ligumia subrostrata (Say) will maintain a steady state for Na when acclimated to an artificial pondwater. Prostaglandin E2 (0.6 μM/g dry tissue) injected into the blood cause an 80% reduction of Na influx and the animals experience a net loss of Na. Injections of indomethacin (0.1 μM/g dry tissue), a prostaglandin synthetase inhibitor, cause a doubling of Na influx relative to control animals. Prostaglandin‐like material can be extracted from the blood of L. subrostrata and may be a component of the endocrine control of ion regulation in freshwater bivalves.
Influence of dietary protein restriction on ovulation, fertilization rates and pre‐implantation embryonic development in mice
Authors: Muños Gladys , Bongiorni‐Malavé Inés
Published: June 2005

Eggs were recovered from 153 adult female mice fed either a normal (27% protein) or a protein‐deficient (8% protein) diet from day 15 (Group I) or 30 (Group 11) before mating until sacrifice. The females were mated with fertile males and sacrificed 48, 72, 96 or 120 hours after observation of vaginal plugs. The study was performed with females that ovulated spontaneously and with females induced to ovulate by injection of pregnant mare's serum gonadotrophin and human chorionic gonadotrophin. Without gonadotrophin treatment, significantly fewer eggs were recovered from malnourished than from normal females. However, after hormonal treatment, the number of eggs ovulated by malnourished and normal females increased similarly.

About 50% of the eggs recovered from malnourished females in both groups I and II were cleaved whereas 90% of the eggs recovered from well‐nourished females were cleaved. The development of the cleaved eggs from protein deficient females was delayed and asynchronous in comparison with that of eggs from normal females. Embryos recovered from malnourished females also were retarded in differentiation of morulae to blastocysts. It is concluded that a protein‐restricted diet adversely affects the fertilization of eggs as well as their early development and differentiation.
Temporal specificity of hemoglobin synthesis in the fat body of Chironomus thummi during development
Authors: Schin Kissu , Laufer Hans , Clark Ralph M.
Published: June 2005

Hemoglobin (Hb) synthesis in the subepidermal fat body cell during the development of Chironomus thummi was investigated by using positive diamino‐benzidine (DAB) reaction as an indicator for the presence of Hb. The localization of DAB reaction products in the ER and Golgi cisternae is stage‐specific. Active synthesis of Hb, as indicated by heavy deposits of reactive products, is interrupted during third‐fourth larval ecdysis, resumes about the fourth day of the fourth instar, continues throughout the fourth instar and stops again shortly before the transition from the pharate pupa to the pharate adult at which time the fat body shows numerous autophagic vacuoles. These results support the concept of the existence of specific switches in the production, release and degradation of Hb present in Chironomus.
Estimation of haploid cell content of parthenogenetic turkey embryos: A cytofluorometric study
Authors: Deford Linda S. , Buss Edward G. , Todd Paul , Wood James C. S.
Published: June 2005

A quantitative cytofluorometric study was undertaken to test the proposition that parthenogenetic development in turkeys begins in a haploid cell and proceeds toward the development of a completely diploid embryo. Embryo cell suspensions were obtained from eggs laid by virgin Beltsville Small White (BSW) turkey hens, and the cells from individual embryos were fluorescently stained with acriflavine, which is specific for DNA. The fluorescent emissions from individual cell nuclei were analyzed on a modified Bio/Physics Cytofluorograf, Model 6300A, and DNA distributions were obtained by analyzing nearly all of the cells in embryos ranging in age from five to nine days. These distributions were compared by computer analysis to the DNA distribution of a normally produced embryo. The DNA distributions revealed that many embryos contained large proportions of haploid cells and other abnormal cells. This study of haploid cells lends further support to the proposition that parthenogenesis in turkeys originates in a haploid egg cell, and diploidization observed in embryos occurs after meiosis. It was also shown that proportions of haploid and other non‐diploid cells declined with increasing embryo age.
Mechanisms of the compensation of blood respiratory acid‐base disturbances in the shore crab, Carcinus maenas (L.)
Authors: Truchot J. ‐P.
Published: June 2005

Apparent exchange of base with the external water was measured in crabs under various experimental conditions where compensation of blood respiratory acid‐base disturbances is known to occur. Crabs reimmersed after a long emersion time, or returned to normal conditions after hyperoxic or hypercapnic exposure, or loaded with sodium bicarbonate, apparently excrete a significant amount of an unidentified base to the external water. Conversely, an apparent acid output occurs during the first hours of an hyperoxic or hypercapnic treatment. As demonstrated by significant changes of the titration alkalinity of the respired water, the site of these exchange processes appears to be mainly the gills. Antennal gland excretion seems of minor importance as shown by obstructing the urinary pores or measuring urine acid‐base parameters. It is also inferred that exchange mechanisms between the cells and the extracellular fluid are also involved in the compensation of blood respiratory acidbase disturbances.
Neural regulation of cholinesterase in newt skeletal muscle. III. Regulation in vitro by proteins from chick embryo brains
Authors: Rathbone Michel P. , Vickers John D. , Logan David M.
Published: June 2005

Triceps muscles of newts (Notophthalmus viridescens) lose AChE activity and show characteristic changes of various molecular forms of AChE after denervation in vivo or when maintained in organ culture (Rathbone et al., '79b). We examined the ability of nerve explants or homogenates from various sources to prevent the changes in total activity and molecular forms of AChE when added to the cultured muscles. These included dorsal root (sensory) ganglia from larval and adult Ambystoma tigrinum, from Plethodon cinereus and from chick embryo (10‐20 days in ovo). Sympathetic ganglia and brain homogenates offered the best combination of AChE‐maintaining activity and ready availability as a source from which to purify the active factor(s). The extracts of chick embryo brains (CBE) when added to newt triceps in organ culture both maintained total AChE activity and prevented alterations in the activity of the various molecular forms of AChE that normally occur after denervation or in organ culture. The active factor(s) were heat labile, trypsin sensitive but RNAase insensitive and had an apparent molecular weight of <20,000 daltons. Nerve growth factor, bovine serum albumin and RNA from chick embryo brains were all ineffective in maintaining the AChE activity of the muscles. The brain extracts also contained material of molecular weight >50,000 daltons that enhanced the loss of AChE from the muscles.

It is concluded that embryonic chick brain extract is a plentiful source of neurotrophically active material from which a factor, most likely a small protein, can be purified for examination of the physiological role of putative neurotrophic factor.
Evolution of patterns of differential gene expression: A comparison of the temporal and spatial patterns of lsozyme locus expression in two closely related fish species (northern largemouth bass, Micropterus salmoides salmoides, and Smallmouth Bass, Micropterus dolomieui)
Authors: Philipp David P. , Childers William F. , Whitt Gregory S.
Published: June 2005

The timing of the onset of developmental expression of 33 loci encoding various enzymes and isozymes was determined for two closely related species of fish, the northern largemouth bass, Micropterus salmoides salmoides, and the smallmouth bass, M. dolomieui. The patterns of gene expression among the different tissues in adults were also investigated. The tissue and developmental expressions of these enzymes and isozymes were visualized by histochemical staining after starch gel electrophoresis. The differential expression of homologous loci within and among the different adult tissues of these two related species is virtually identical. The ontogenetic times of expression during the embryogenesis of both species are also quite similar for these same homologous loci. The ontogenetic patterns of differential gene expression for these two species differ somewhat from those of a more distantly related species within the family Centrarchidae, the green sunfish, Lepomis cyanellus. These results are consistent with the hypothesis that there is an increase in divergence of gene expression in species which are progressively more distantly related.
Genetics of the malate dehydrogenase isozymes of the isopod porcellio scaber
Authors: Sassaman Clay
Published: June 2005

Electrophoretic analysis of malate dehydrogenase (MDH) in extracts of the isopod Porcellio scaber Latr. indicates two zones of activity, MDH‐1 and MDH‐2, corresponding to the cytoplasmic and mitochondrial forms respectively. Electrophoretic variants of both forms have been isolated from natural populations. The locus encoding MDH‐1 has at least three alleles in appreciable frequency; the MDH‐2 locus has two. Breeding studies indicate that variants of both forms of MDH have Mendelian inheritance patterns, and that the two proteins are encoded by independently assorting autosomal genes. Neither MDH gene is apparently linked to the autosomal gene which encodes phosphoglucose isomerase.
Changes observed in bone during hibernation using procion red dye as a matrical marker
Authors: Steinberg Barry , Singh Inder Jit , Mitchell Ormond G.
Published: June 2005

Visual examination of the intensity of Procion dye in hamster femurs revealed that dye incorporation decreased during hibernation. Little or no dye was observed after hibernation lasting longer than 50 days. It seems that hibernation may be associated with increased bone resorption and a loss of bone matrix.
Ultrastructure of blastocoel material in blastulae and gastrulae of the sea urchin Lytechinus pictus
Authors: Katow Hideki , Solursh Michael
Published: June 2005

The ultrastructure of blastocoelic material in blastulae and gastrulae of the sea urchin Lytechinus pictus was revealed by transmission and scanning electron microscopy.

The blastocoel of blastulae contained 30 nm diameter granules, aggregated in long chains. In gastrulae, on the other hand, another component was present: fine fibers. The 30 nm granules were attached to the surface of these fine fibers to form a thicker, rough‐surfaced complex fibrous structure.

Embryos cultured in sulfate deficient sea water had greatly reduced numbers of 30 nm granules in the blastocoel. The fine fibers appeared normal. Consequently, the 30 nm granules are selectively sensitive to sulfate deprivation.
Developmental physiology of cestodes. XV. A system for testing possible crowding factors in vitro
Authors: Insler Gayle Dranch , Roberts Larry S.
Published: June 2005

It has been long known that Hymenolepis diminuta (Cestoda: Cyclophyllidea) exhibits a crowding effect when developing in its definitive host, the rat. Experiments were designed to test whether the worms might secrete substances inhibitory to the growth of other worms, thus helping to account for the crowding effect. A worm conditioned saline (WCS) was prepared by incubation of 10‐day‐old worms from crowded infections in a balanced salt solution, then testing the effect of the WCS on the incorporation of 3H‐thymidine into the DNA of other worms from uncrowded infections. Incorporation of 3H‐thymidine into the DNA of the anterior regions of the test worms was inhibited by about 50–60% compared to controls. Incubation in WCS also inhibited incorporation of 3H‐uridine and 3H‐mino acids into RNA and protein, respectively, of the test worms. These responses are similar to those previously observed in crowded worms. The inhibition was apparently not a cytotoxic, phenomenon since the effect was reversible, the energy charge of worms incubated in WCS was the same as that of controls, and the tegument of incubated worms was intact.
Developmental physiology of cestodes XVI. Effects of certain excretory products on incorporation of 3H‐thymidine into DNA of Hymenolepis diminuta
Authors: Insler Gayle Dranch , Roberts Larry S.
Published: June 2005

Succinate and acetate, which are excreted by Hymenolepis diminuta (Cestoda: Cyclophyllidea), account for about half the inhibition of DNA synthesis observed when the worms are incubated in a “worm conditioned saline” (WCS). Succinate is probably responsible for the bulk of the inhibition, while lactate, which is also excreted by the worms, is inactive. Ammonia and urea at concentrations present in the WCS do not inhibit incorporation of thymidine into DNA. Incubation in WCS or 12 mM succinate, for more than 1 hr inhibits glucose uptake by the worms, but the effect is reversible; therefore, the inhibition is not a result of permanent damage. Concentrations of succinate found in WCS appear physiologic since they agree well with levels found in the small intestines of rats infected with high density populations of H. diminuta.
Neuromuscular mechanisms in the insect foregut
Authors: Yamamoto Daisuke , Fukami Jun‐Ichi
Published: June 2005

Bioelectric potentials were recorded intracellularly from the foregut muscle fibres of the larva of the waxmoth Gelleria mellonella.

Myogenic spikes were generated spontaneously or by direct stimulation of the fibres of the crop, anterior and posterior proventriculus. The action potentials from these three regions were distinguishable from each other by their characteristic shapes and duration. Pacemaker potentials were recorded from fibres of the crop and the posterior proventriculus but not recorded from the anterior proventriculus, where only follower type potential changes could be observed.

Spontaneous and evoked EJPs were obtained from the crop and the posterior proventriculus but were not recorded from the anterior proventriculus. The reversal potential for evoked EJPs was estimated at about 0 mV by a method of extrapolation.

Chemical sensitivity of evoked EJPs was examined. Seven putative transmitters including acetylcholine, L‐glutamic acid, L‐aspertic acid, norepinephrine, octopamine, dopamine, and 5‐hydroxytryptamine were tested. It was found that L‐glutamic acid depressed EJP at about 10−4 M. Specific agonists and antagonists were also administered on EJPs. Effects of atropine, phentolamine, tyramine, and BOL‐148 were negligible and eserine and propranolol blocked transmission at 5 × 10−4 M. D‐tubocurarine (5 × 10−4 M) enhanced the EJP, with occasional exceptions. The actions of the last three drugs were, however, inconsistent, and were considered to be nonspecific. In contrast, kainic acid had consistent effects; potentiated EJPs at 2.5‐,5 × 10−5 M and blocked at 1 × 10−3 M. From these observations it was suspected that among seven compounds tested, L‐glutamic acid is the most probable candidate for a transmitter.

The firing rhythm of myogenic spikes generating spontaneously could be reset by neurally evoked spikes.