bluuebunny/crossref_metadata_2025_split huggingface dataset:
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

AbstractGel 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

AbstractDecay 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

AbstractThe 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

AbstractIn 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

AbstractBidirectional 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

AbstractRecessive 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

AbstractGynogenetic 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

AbstractPillbugs 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

AbstractIn 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

AbstractThe 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

AbstractIn 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

AbstractThe 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

AbstractFully 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

AbstractMouse 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

AbstractHydrostatic 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

AbstractAntisera 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

AbstractMetridium 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

AbstractBody 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

AbstractLigumia 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

AbstractEggs 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

AbstractHemoglobin (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.