bluuebunny/crossref_metadata_2025 huggingface dataset:
The appearance and distribution of vaginal antigen during the differentiation of the cervicovaginal epithelium in normal and estradiol‐treated mice
Authors: Forsberg John‐Gunnar , Kvinnsland Stener
Published: June 2005

Rabbits were immunized with vaginal epithelium from ovariectomized and estradiol‐injected adult mice. A crude IgG solution was prepared from the immune serum and was used for immunofluorescence studies (indirect method) of the appearance of antigen(s) specific for the vaginal epithelium during the differentiation of the cervicovaginal epithelium in neonatal mice. In neonatal untreated mice, the appearance of the antigen could be correlated with the mitotic activity and morphological transformation of the vaginal epithelium.

Estradiol injected into neonatal mice had a two‐fold effect: it caused a precocious appearance of visible specific antigen in the untransformed pseudostratified cervicovaginal epithelium; however, in some mice it prevented the appearance of any visible antigen in the cervical epithelium, possibly by way of its inhibiting effect on cell divisions in this region. It is suggested that the epithelial cells must pass a “crucial mitosis” before being able to synthesize the antigen.

The distribution of the antigen was also studied in immature and adult ovariectomized and estradiol injected mice. Estradiol strongly increased the small amount of antigen seen in the superficial cell layer of ovariectomized animals.
Is abnormal limb bud morphology in the mutant Talpid2 chick embryo a result of altered intercellular adhesion? Studies employing cell sorting and fragment fusion
Authors: Niederman Richard , Armstrong Peter B.
Published: June 2005

In the past, studies of avian limb morphogenesis emphasized epithelial‐mesenchymal tissue interactions and problems of determination of limb symmetry. In contrast, a recent hypothesis, based on studies of the aggregation rates of dissociated cells and on computer modeling, proposes that the paddle shaped polydactylous limb of the talpid3 mutant is the result of increased intercellular adhesion of limb bud mesoderm cells during limb development. The notion that differences in intercellular adhesion may have profound effects on limb morphogenesis has not been critically explored previously.

The present experimental approach includes studies of cell sorting in aggregates containing both talpid2 and wild‐type cells. In this system, adhesive differences should result in cell sorting. Instead, cell sorting did not occur, indicating by this test at least, that limb bud mesoderm cells of talpid2 and wild‐type embryos are equally adhesive. This conclusion finds support from studies involving tissue spreading in fused fragments of talpid2 and wild‐type limb bud mesenchyme tissue and in studies of kinetics of aggregation of dissociated cells.
The behavior of the acetylcholinesterase cells of the anterior pituitary gland of artificially photostimulated female white‐crowned sparrows
Authors: Haase Eberhard , Farner Donald S.
Published: June 2005

In Zonotrichia leucophrys gambelii complete testicular development is induced in captive males subjected to long daily photoperiods. In identically treated females ovarian development is only partial. This partial development of the ovary, and the subsequent premature regression thereof, correlate with changes in activity of the “acetylcholinesterase cells” of the pars distalis. This adds to the evidence that these cells are gonadotropes.
Inhibition of cleavage and hatching of sea urchin embryos by serotonin
Authors: Deeb Samir S.
Published: June 2005

The addition of low levels of serotonin (20–50 μg/ml) to the rearing medium of sea urchin embryos specifically inhibits the hatching process by blocking the synthesis of an active hatching enzyme. Other developmental processes seem to be unaffected. Embryos are sensitive to serotonin during the first three cleavage divisions only. The uptake of RNA and protein precursors, and the rate of RNA synthesis are unaffected by serotonin, whereas the rate of protein synthesis is elevated by approximately 45% during the 2‐cell to 16‐cell interval of development.

The addition of higher levels of serotonin, 75 and 100 μg/ml, causes retardation and blockage of cleavage division respectively.
Defective histogenesis and morphogenesis in the anterior shank skin of the scaleless mutant
Authors: Sawyer Roger H. , Abbott Ursula K.
Published: June 2005

Timed‐sequence studies of scaleless anterior shank skin have shown that both histogenesis and morphogenesis are abnormal. An epidermal placode does not form in the mutant and thus the subsequent morphogenetic movements of placode into scale ridge are blocked as well. The dermis of the anterior shank remains flat rather than forming overlapping ridges. Two histologically distinct epidermal surfaces (outer and inner) are formed on either side of a normal scale ridge. In scaleless only a single epidermal surface develops and this is unlike either surface of a normal scale. An isolated dermal ridge of 16‐day normal embryonic scale can induce eight‐day chorionic epithelium to form both the outer and inner epidermal surfaces. Scaleless dermis of the same age when recombined with eight‐day CE will induce an epidermis typical of the normal outer scale surface, but no inner epidermal surface is formed. Previous studies have shown that the genetic defect is expressed in the epidermis and that at earlier stages scaleless dermis can, when associated with a normal epithelium, participate in placode formation and histogenesis of both epidermal surfaces. It seems reasonable to conclude that placode formation is initiated by the epidermis which thereby establishes heterogeneity in the scale dermis; thereafter, the scale dermis directs the histogenesis of the two epidermal surfaces.
Frequency response of the ear of the Tokay gecko
Authors: Manley Geoffrey A.
Published: June 2005

A comparative analysis of the frequency response of the inner and middle ear of Gekko gecko is described. Tungsten microelectrodes were used to isolate single auditory neurons in the cochlear nucleus in order to study their frequency selectivity and sensitivity.

Neurons were detected with characteristic frequencies up to 5 kHz, and tuning curves were similar to those of mammalian systems. The single neuron responses were strongly frequency selective, as was expected from the presence of a well‐differentiated basilar membrane. The sensitivity of this hearing system compares favorably with that of birds and mammals and is the most sensitive of those reptiles yet studied with neurophysiological techniques.

The middle‐ear response was studied with the Mössbauer system and shows a typical non‐mammalian response. Amplitude of the drum or columella is constant up to 1 kHz, then falls off rapidly at higher frequencies. A lever action between drum and columella presumably aids impedance matching. The overall ear sensitivity function was corrected for middle ear response and reveals a true inner‐ear sensitivity curve. Analysis of the single‐unit data is aided by a knowledge of the middle‐ear response, and somewhat different conclusions are reached after correction of the data to constant columella amplitude.
Physiological studies on supercooled killifish (Fundulus heteroclitus). IV. Carbohydrate metabolism in hypophysectomized killifish at subzero temperatures
Authors: Umminger Bruce L.
Published: June 2005

Intact Fundulus heteroclitus, acclimated to −1.5°C in sea water, showed increased levels of serum glucose, decreased levels of hepatic glycogen and unchanged levels of serum non‐glucose free carbohydrates and muscle glycogen when compared with controls at 20°C. In hypophysectomized killifish, acclimation to subzero temperatures was accompanied by hyperglycemia, increased concentrations of muscle glycogen and increased levels of serum non‐glucose free carbohydrates. Hepatic glycogen concentration as mg/g of liver was unchanged in cold‐acclimated hypophysectomized fish, but liver size increased so that total hepatic glycogen (mg/g of fish) was markedly elevated. The pituitary gland was not involved in eliciting the cold‐induced hyperglycemia but was important in regulating other aspects of carbohydrate metabolism.
Action of intrinsic laryngeal muscles during release calling in leopard frog
Authors: Schmidt Robert S.
Published: June 2005

Cinematographic, gross anatomical, muscle contraction, histological, and electromyographic data were used to determine the actions of the intrinsic laryngeal muscles of the leopard frog (Rana pipiens pipiens) during release calling. The dilator muscles act as glottal openers, the posterior constrictors as vocal cord opposers, and the external and anterior constrictors as glottal closers. The posterior constrictors do not “tense” the vocal cords, but merely bring them into opposition at the midline by pulling on the vocal pulvinaria, which act as levers. The anterior constrictors probably are not involved in vocal cord changes. Most of the release call trills (glottal trills) are produced by a brief opening of the glottis (which is quickly terminated by contraction of the glottal closers) during which there is a brief vocal cord opposition. The final trills of the call (vocal cord trills) occur during a continuous, prolonged opening of the glottis and are produced by the relaxation oscillations of the vocal cords.
The requirement for RNA synthesis in the differentiation of cultured chick embryo chondrocytes
Authors: Solursh Michael , Meier Stephen
Published: June 2005

Secondary chick embryo sternal chondrocyte colonies, derived from differentiated clones, were treated with 0.005 μg/ml of actinomycin D for 18 hours. While RNA synthesis was inhibited by 70%, both growth and matrix accumulation were inhibited. The incorporation of 3H‐uridine into acid precipitable‐base hydrolyzable material, 35SO4 into hyaluronidase‐sensitive material, and of 3H‐proline into collagenase sensitive and insensitive material was measured in high density cultures treated with various doses of actinomycin D for 18 hours. The inhibition of sulfate incorporation was highly correlated with RNA synthesis and was observable within the first six hours after drug addition. Ethidium bromide and lucanthasone had no effect on sulfate incorporation. On the other hand, collagen synthesis was more resistant to actinomycin D treatment and was not inhibited until non‐collagenous protein synthesis was also inhibited. The results are discussed in terms of the independent regulation of the synthesis of two specialized cell products made by the same cell.
Hypothalamic control of the hypophyseal gonadotropic function in the adult male green frog, Rana esculenta L.
Authors: Rastogi Rakesh K. , Chieffi G.
Published: June 2005

Removal of the pars distalis, homoiotopic and ectopic autografting of the pars distalis, and transection of the hypothalamo‐hypophyseal link was done and their effect upon the cytology of the pars distalis and its gonadotropic functions was studied in the male green frog, Rana esculenta. Removal of pars distalis led to the regression of gonads and secondary sex organs. The gonadotropic activity of the pars distalis regrafted under the median eminence was comparable to that of the sham‐operated control except that in the gland oriented at an angle of 180° the thumb pads were involuted. The normal functional activity of the regrafted gland can be explained by the contact re‐established between the grafted gland and the portal vessels at the level of the median eminence as ascertained by injections of India ink. The ectopic pars distalis graft showed a general cytological disorganization and regression of the various cell types and its gonadotropic function appeared to be extremely poor. Transection of the hypothalamo‐hypophyseal connections diminished the gonadotropic effectiveness of the pars distalis.
Further studies on the maternal effect of the o gene in the Mexican axolotl
Authors: Briggs Robert
Published: June 2005

Axolotl females homozygous for o produce eggs which are fertilizable and cleave normally, but are invariably arrested during gastrulation. This block can be corrected by injecting the eggs with nuclear sap from normal (o+/o+ or o+/o) ovarian oocytes. The factor responsible for the correction is designated o+ substance. In this paper we show the following: 1. The o+ substance is not species specific. Oocyte nuclear sap from a variety of amphibians is about as effective as that of the axolotl itself in correcting the maternal effect of o. The cytoplasm of ovarian oocytes is inactive or very weakly active. That of some species (e.g., Xenopus laevis) exerts no discernable effect. That of others (e.g., Rana pipiens) is highly toxic, killing axolotl eggs shortly after it is injected into them. 2. The o+ substance is synthesized during most of the growth of the oocytes. Oocytes assayed just at the beginning of yolk deposition or at intermediate stages contain o+ substance of about the same activity, volume for volume, as that of fully grown oocytes. 3. Uncorrected o+/o and o/o offspring of o/o females are indistinguishable — all stop at gastrulation. When corrected by injections of o+ substance they respond equally at first and develop to an advanced embryonic stage (St. 37). At this time 50% of the embryos (o/o) stop, the other 50% (o+/o) continue to develop. These results indicate that the o+ gene does not function in early development, but can begin to do so in advanced embryos.
Seasonal variation of newt forelimb regeneration under controlled environmental conditions
Authors: Schauble Muriel K.
Published: June 2005

Forelimb regeneration studies using the newt, Notophthalmus viridescens, were done under constant environmental conditions at 20°C. A series of three‐month regenerative studies were done during a two and one‐half year period. Under conditions which eliminated factors known to affect regeneration, such as temperature and variation in light‐dark cycle, a significant seasonal variation in the regenerative process was found. The rate and amount of regenerative new growth during the summer was enhanced over that in winter. A series of repetitive regenerations in the same group of animals demonstrated that this variation was cyclic under controlled environmental conditions for long periods of time. It is suggested that a cyclic biologic rhythm, probably endocrine in nature, is responsible for the phenomenon.
Protein incorporation by isolated amphibian oocytes. II. A survey of inhibitors
Authors: Wallace Robin A. , Ho Ti
Published: June 2005

A variety of some of the more commonly used metabolic inhibitors and several substances previously found to influence protein incorporation by other types of cells were tested for their effects on protein incorporation by growing oocytes in vitro. With the exception of the uncouplers and the sulfhydryl reagent iodoacetate, the metabolic inhibitors at concentrations of 10 −3 M or less had little influence on sequestering activity. Cycloheximide, at concentrations which essentially abolished all protein synthesis, reduced protein incorporation by only 40–50%. The most pronounced inhibition of protein uptake without apparent cytotoxic side effects was provided by vinblastine and sulfhydryl reagents (especially trivalent arsenicals). The sulfhydryl reagents appeared to exert their effect primarily on the oocyte rather than the proteins of the medium. The results are evaluated both in terms of their relevance to previous studies with other cell systems and their significance towards understanding the mechanisms involved in the incorporation of macromolecules by cells. Finally, a preliminary model of protein incorporation by the oocyte is presented for further testing.
Migration of follicle cells through the zona pellucida and their sequestration by human oocytes in vitro
Authors: Zamboni L. , Smith D. Moore , Thompson R. S.
Published: June 2005

This study describes the fine morphologic features of follicle cell penetration through the zonae pellucidae of cultured human oocytes and the subsequent sequestration of the cells into the ooplasm. The observations made in this study would indicate that follicle cells progress through the zona pellucida because of their motility and that their sequestration by the oocytes occurs by phagocytosis. These phenomena are discussed on the basis of the knowledge of the process of sperm progression toward and into the egg at fertilization.
Regeneration in the African lungfish, Protopterus. II. Branching structures
Authors: Conant Elizabeth Babbott
Published: June 2005

It is possible to elicit the growth of a lateral branch from either the pectoral or the pelvic fin of the African lungfish Protopterus by excising a wedge of tissue, including cartilage, from the original limb. In pectoral limbs, 18 notches produced four bifids, but in pelvic limbs only one out of 14 cuts resulted in a branching element. Although cuts were distributed along the length of the limbs and along both anterior and posterior faces, accessory structures were elicited only from the posterior and posterior‐dorsal faces of the pectoral limb and from the anterior edge of the pelvic. The new branch was always of a size, proportion, and function nearly identical with that of the original, and to date none has grown longer than the equivalent branch of the primary limb. One broken pectoral limb gave rise spontaneously to a bifid growth.

Fully developed horizontal branches effect changes in the long axis of the limb from which they have grown. Although the new filament first grows out perpendicular to the long axis of the primary element, it later assumes a shallower angle. Subsequent skewing of the axis of the primary limb results in a “Y” configuration. However, one vertically directed branch on the posteriordorsal surface of a pectoral limb, after ten months, still retains its original orientation, there having been no change in either its orientation or that of the original limb. One caudal anomaly is figured.
Studies of water uptake in the euryhaline crab, Rhithropanopeus harrisi
Authors: Capen Ronald L.
Published: June 2005

Water uptake in the crab, Rhithropanopeus harrisi, was studied using D2O (deuterium oxide) as a label. Results were expressed as per cent saturation, or the D2O concentration in the blood, attained in a 30‐minute exposure to D2O at 20°C, expressed as a percentage of the D2O concentration in the bathing medium. Crabs acclimated to 75% sea water (SW), to which the blood is about isosmotic, had a mean per cent saturation of 51.8, and in 10% SW‐acclimated crabs (blood hyperosmotic by about 40% SW) the mean per cent saturation was 33.9. Thus, water uptake, or exchange, is slower when the osmotic gradient favors net water uptake than when no osmotic gradient exists. In gill chamber perfusion experiments at least 87% of the total water influx in 10% SW and 92% of the total in 75% SW are taken up in the gill chambers, the gills probably being responsible for most, if not all, of the uptake. The time course of acclimation between 10% SW and 75% SW was followed in both directions. Measurable changes in water uptake occurred in 30 minutes; half the change from 75% SW to 10% SW occurred in two hours (seven hours for the transfer from 10% SW to 75% SW), and over 90% of full acclimation was reached in two days.

Gill chamber perfusion experiments showed that the receptor or receptors which perceive the change between 10% and 75% SW and mediate the change in water uptake are not in the gill chamber. Thus the system responsible for the change in water uptake is composed of at least a receptor with some means of communication (presumably nervous or hormonal) with the effectors (probably the gills).

The use of Na+‐free and Cl−‐free D2O media showed that the absence of these ions did not affect water uptake, and that the change in water uptake was not caused by a change in influx of these ions.
The effects of cytochalasin B on the events of fertilization in the surf clam, Spisula solidissima. I. Polar body formation
Authors: Longo Frank J.
Published: June 2005

Investigations, employing the drug cytochalasin B (CB), have been carried out in an effort to determine the mechanisms underlying the processes involved in polar body formation and their possible relation to cytokinesis of mitosis. Fertilized eggs of the surf clam, Spisula were treated with 1 or 10 μg/ml CB and prepared for light and electron microscopy. Germinal vesicle breakdown and formation of the first meiotic spindle are similar in CB treated zygotes and in controls. At anaphase I a cytoplasmic protrusion develops at the site of the peripheral aster and contains dyad chromosomes. Although the inner aspect of the plasma membrane of this projection in CB treated zygotes is lined with a discontinuous layer of fine textured material, a cleavage furrow fails to form and the cytoplasmic bleb gradually regresses in size. The failure of the presumptive first polar body to cleave results in the presence of two groups of dyads within the zygote. These become aligned on separate or shared meiotic spindles in preparation for the second meiotic division. At anaphase II a protrusion, structurally similar to the first, is formed which also fails to separate from the zygote via a cleavage furrow. Due to the absence of polar body formation, four groups of maternally derived chromatin may be observed at the animal hemisphere of the zygote. These groups are organized into female pronuclei (usually 4) which may not be of equal ploidy. Failure of the cleavage furrow to develop during polar body formation in CB treated zygotes suggests that the filamentous material associated with the leading edge of the furrow of control specimens may function in a manner proposed for the contractile ring of mitotic cells.
The influence of ammonia on the transition to ureotelism in Xenopus laevis
Authors: Janssens P. A.
Published: June 2005

Toads of the species Xenopus laevis were immersed in 5 mM NH4Cl or 5 mM NaCl for periods of up to 28 days. In stronger solutions of NH4Cl, toads died within one hour. The rate of excretion of ammonia and urea and the activities of carbamyl phosphate synthetase, ornithine transcarbamylase, arginase and glutamate dehydrogenase in liver and kidney were measured. In toads in 5 mM NH4Cl, the excretion of urea was increased about ten‐fold, and there were increases in the activities of carbamyl phosphate synthetase and glutamate dehydrogenase in the liver. The activities of ornithine transcarbamylase and arginase in the liver, and of glutamate dehydrogenase in the kidney, were unaffected. In toads in 5 mM NaCl, there was no change in the rate of urea excretion or in the activities of any of the enzymes assayed. It was concluded that a rise in tissue ammonia levels is followed by alterations in the metabolic pathways of the toads which result in a decrease in those levels. Thus, the transition to ureotelism in X. laevis is triggered by an increase in tissue ammonia levels. Because there was no response to immersion in 5 mM NaCl, it is concluded that a slight increase in the osmotic pressure of the external medium has no effect, and that urea is of little significance in osmotic regulation in this toad.
Purification and site of synthesis of Aedes aegypti yolk proteins
Authors: Hagedorn H. H. , Judson C. L.
Published: June 2005

The identity and site of synthesis of the yolk proteins of the mosquito Aedes aegypti were studied. Disc gel electrophoresis of freshly prepared egg yolk revealed a predominant protein (YP‐1) which stained for bound lipid and carbohydrate. The molecular weight of the protein complex was estimated to be 2.7 × 105. It was present in vitellogenic females and absent in males and unfed females.

Yolk Protein‐1 was purified by Sepharose and DEAE column chromatography and represented 75% of the protein extractable from the egg. The lipids conjugated to YP‐1 were identified as phosphatidyl choline, phosphatidyl ethanolamine and several steroids. The carbohydrate content was estimated as 10.5% with a phenol‐sulfuric acid method, and 5.8% with an orcinol method.

The site of yolk protein synthesis was determined using antibody to purified yolk to precipitate labeled yolk proteins from organ culture media. Only the fat body synthesized antibody precipitable material. Synthesis began five to six hours after the blood meal, reached a peak of activity by 20 hours and declined to low levels of synthesis by 72 hours. These data correlate well with endocrino‐logical evidence indicating that egg development requires a hormonal factor from the head from four to eight hours after the blood meal.
Nickel uptake by sea urchin embryos and their subsequent development
Authors: Timourian Hector , Watchmaker George
Published: June 2005

There is active uptake of radioactive nickel by fertilized eggs and embryos of the sea urchin Lytechinus pictus. The nickel taken into the cells is free and can be released by the addition of exogenous, non‐radioactive nickel. The morphological development of embryos raised in sea water containing 10−2 to 10−6 M NiCl2 was investigated. Nickel uptake is initiated right after fertilization, but its effect on development does not appear until much later. Embryos grown in 10−2 and 10−3 M NiCl2 cleaved at a normal rate and formed blastulae but did not gastrulate. Embryos grown in 10 −4 to 10−6 M NiCl2 were able to gastrulate but failed to develop dorsoventral symmetry and formed radialized larvae.
On the neuroendocrine control of ovarian development in the Monarch butterfly
Authors: Barker John F. , Herman William S.
Published: June 2005

Several methods have been used to examine the role of the neuroendocrine system in the regulation of ovarian development in the Monarch butterfly, Danaus plexippus. Ovarian development ceases after neck ligature, removal of the retrocerebral complex, disconnection of the retrocerebral complex from the brain, and after removal of the neurosecretory cells and associated neurons of the medial pars intercerebralis. Removal of the retrocerebral complex causes oocyte resorption in mature females. Normal ovarian development was obtained by injecting material with high juvenile hormone activity into animals lacking the retrocerebral complex, but normal ovarian development was not obtained in neck‐ligatured animals injected with the same material. The results suggest that the brain and corpora allata both act to regulate ovarian growth in this species. The brain apparently stimulates posteclosion corpora allata activity. The medial neurosecretory cells of the pars intercerebralis, or some other cephalic center, may produce a hormone requisite for quantitatively normal öogenesis. The corpora allata apparently stimulate vitellogenin synthesis.
Oxidative phosphorylation in mitochondria during, embryonic development
Authors: Henson Miriam M.
Published: June 2005

P:O ratios have been determined in mitochondria from the liver and skeletal muscle of chicks ranging in age from eight days of incubation through hatching. The values obtained remain constant throughout development and are the same as those of mitochondria from corresponding tissues of the adult. Developmental changes in respiratory control (RC) show variations depending on the tissue and the substrate oxidized. RC is constant in liver mitochondria with all substrates; in muscle mitochondria, RC increases with glutamate and αketoglutarate, while with malate, RC shows a marked decrease prior to hatching. Similarly, changes in specific activity of oxidation and phosphorylation in mitochondria vary with tissue and developmental stage. In liver mitochondria, specific activities of oxidation and phosphorylation with glutamate and αketoglutarate decrease during development; in muscle mitochondria, specific activities with these substrates increase. With malate, specific activities increase in liver, but decrease in muscle mitochondria; in the latter tissue this occurs at about the time of hatching. Added cytochrome c increases oxidation rate of muscle mitochondria, the increase being progressively greater the older the animals from which the mitochondria are derived.
Dimensions of control of cortical patterns in Euplotes: The role of pre‐existing structure, the clonal life cycle, and the genotype
Authors: Frankel Joseph
Published: June 2005

Within each of three investigated strains of Euplotes minuta (autogamous — A23; non‐autogamous — K7, VF17) variation was observed in the number of ciliary rows commonly manifested. Subcloning of two of these strains (A23, K7) revealed a strong tendency toward vegetative perpetuation of the preexisting row number; differences within genetically homogeneous material could persist over 200 fissions of serial propagation. However, initially different subclones tended gradually to converge toward a common distribution of row number. The rate of convergence depended on the strain and on the degree of senility.

Non‐autogamous strains of E. minuta became senile at a clonal age of 500 to 700 fissions. Senility was manifested by reduced fission rates and by low survival after conjugation. Senile lines showed a reduced average ciliary row number, an increased variation in the row numbers commonly found, and a reduced fidelity in the vegetative propagation of preexisting row number. Initiation of new life cycles by conjugation reversed all of these effects.

Young (non‐senile) clones displayed a characteristic range of ciliary row numbers, which remained the same following successive initiations of new clonal life cycles. This strain‐specific “stability range” was eight to nine rows for non‐autogamous strains (K7, VF17, and progeny of crosses between them) and nine to ten rows for the autogamous stock A23. The appearance of progeny lines with substantial numbers of ten‐rowed cells following a backcross of the A23 X VF17 F1 to the A23 parent (Heckmann and Frankel, '68) could therefore only have been due to genie contributions from the A23 parent. Reanalysis of the earlier data combined with results of the present study strongly suggest that the difference in stability range between the autogamous and non‐autogamous strains has a polygenic basis.
Growth inhibition in Rana pipiens due to sperm irradiation with ultraviolet rays
Authors: Pogany Gilbert C.
Published: June 2005

When sperm are irradiated for periods varying from 5 to 120 seconds at 31 ergs/mm2, then allowed to fertilize untreated eggs, the ensuing embryos display distinct growth inhibition. The degree of growth inhibition is not proportional to the exposure; this is indicated by the condition observed in the five second embryos where growth is most retarded and abnormal. Cells in the irradiated embryos are shown to be smaller than the control. A possible mechanism for this reduced cell size is proposed based on the theory that chromosomes replicate in some linear fashion. It is also proposed that the abnormalities found in embryos subjected for five seconds be used to detect small radiation damages in other organisms.
Progressive alteration in the pattern of nucleic acid metabolism in the newt iris in cultivation
Authors: Jauker Fritz , Yamada Tuneo
Published: June 2005

The dorsal iris of the adult newt (Notophthalmus viridescens) was cultured in vitro for periods up to 12 days and then exposed to [3H] uridine. Labeled RNA extracted from the tissue was studied on a sucrose density gradient. The profiles indicate that incorporation into ribosomal RNA's is progressively increased during the first four days and progressively decreased during the following days. Incorporation into the precursor of ribosomal RNA is also progressively decreased in the later phase. Compared with ribosomal RNA's and their precursor, an RNA fraction with an S value higher than 40 is less affected. A study of incorporation of [3H] thymidine into the trichloroacetic acid‐insoluble fraction of the same tissue cultured in vitro showed a wave of incorporation beginning on day 4 and persisting to the end of the culture period. The data were compared with data obtained for the same tissue left in situ after lentectomy, which depigments and forms a lens.
Pressure and air flow during distress calls of the starling, Sturnus vulgaris (Aves;Passeriformes)
Authors: Gaunt Abbot S. , Stein Robert Carrington , Gaunt Sandra L. L.
Published: June 2005

Present hypotheses for the operation of the syringeal mechanism can be reduced to two models differing in whether closure of the syringeal bore is attributed to a pressure differential on either side of the vibrating membrane or to contraction of the syringeal musculature. Paucity of data, especially for songbirds, concerning the behavior of ventilated air during calling hinders application of either of the models to specific portions of the repertoire of any bird.

Internal and tracheal pressures and air flow are recorded during distress
calls of the starling. Air sac pressures soar, often to more than 20 cm H20 ( × 40
normal respiratory amplitudes), while tracheal pressures are the same or lower
than during respiration. A distress call lasts twice as long as a normal exhala
tion, but flow is reduced and tidal volume increases only slightly. Seemingly,
the syringeal valve can regulate flow across a large, sustained pressure
differential. The inability of birds to vocalize when the interclavicular air sac
is ruptured is more easily explained by an alteration of flow to bypass a closed,
pressure independent valve than a necessity for a high pressure surrounding
the syrinx during vocalization. These studies suggest that reduction of the
syringeal lumen in songbirds is at least partially dependent on active con‐
striction rather than a passive flutter valve. The possible nature and selective
implications of such a mechanism are discussed.
Hamster sperm hyaluronidase. II. Its release from sperm in vitro in relation to the degenerative and normal acrosome reaction
Authors: Talbot Prudence , Franklin Luther E.
Published: June 2005

Hamster sperm incubated in vitro were used to determine: (1) when hyaluronidase is released from sperm undergoing acrosome detachment, i.e., either a degenerative or normal acrosome reaction, and (2) what ultrastructural changes occur in the acrosomes of living sperm during hyaluronidase release. Sperm were incubated up to 4 hours in normal saline, Ham's F‐10, or heat pretreated blood serum. At hourly intervals, the percentages of live (motile) and acrosome reacted sperm were counted, and the supernatant from each sperm sample was assayed for hyaluronidase activity. In normal saline, sperm died during the incubation period, underwent a degenerative acrosome reaction, and gradually released hyaluronidase. In Ham's F‐10, sperm lived throughout the incubation period, did not undergo acrosome detachment, and did not release detectable amounts of hyaluronidase. In heat pretreated blood serum, sperm death did not occur during the incubation period, a surge of hyaluronidase release was complete by 1 hour of incubation, and additional hyaluronidase activity was not detected in the incubation medium between 3 and 4 hours when the normal acrosome reaction was observed. The fine structure of the acrosome was unaltered immediately after the release of hyaluronidase in serum. It was concluded that more than 50% of the mechanically extractable hamster sperm hyaluronidase was released by a factor present in serum and that this release occurred prior to and independently of the normal acrosome reaction. The partial release of hyaluronidase in serum prior to the occurrence of a normal acrosome reaction may indicate that this enzyme has a bifunctional role in reproduction.
Oxygen consumption and lipid content in red and white muscles of antarctic fishes
Authors: Lin Yuan , Dobbs Gary H. , Devries Arthur L.
Published: June 2005

Antarctic nototheniid fishes have red muscle which is restricted to the pectoral girdle region of the body. The muscle masses articulate the pectoral fins whose movement propels the fish during sustained low speed cruising. Both the rate of oxygen consumption and lipid content are higher in the red muscle masses than in white muscle. Electron microscope observations reveal large numbers of lipid droplets and mitochondria arranged in close association with one another. These findings support the hypothesis that red muscle is used for long, sustained swimming motion, and that lipid, rather than glycogen, is the main energy source for this activity.
The role of disulfide reduction in chromatin release from equine sperm
Authors: Wagner Thomas E. , Mann David R. , Vincent Roger C.
Published: June 2005

The induced expulsion of a condensed chromosomal strand from equine sperm head pieces by the combined action of guanidine HCl (0.35M) and β‐mercaptoethanol (5 × 10−3M) is documented by scanning electron microscopy. The circular dichroism spectrum of a disordered gel state of this expelled sperm chromatin is shown and suggests that the DNA component of this chromosomal material may be in the compact ψ‐DNA state, The possible role of ‐S‐S‐reductive breakdown in the sperm chromatin expulsion mechanism during fertilization is discussed.
A function for neurons (DUM) neurosecretory on skeletal muscle of insects
Authors: Hoyle Graham
Published: June 2005

The action of dorsal unpaired median (DUM) neurons of the locust Schistocerca gregaria and the grasshopper Romalea microptera was examined on the intrinsic rhythmic contractions that occur in their jumping muscles. The DUM neuron directly innervating the muscles, DUMETi, causes from partial to complete inhibition of the rhythm outlasting the stimulation by up to several minutes. The extent of inhibition, its time of onset and its duration, are proportional to the number and frequency of impulses. Other DUM neurons either exert a weaker, delayed effect, or none at all.
Inhibition of melanosome transformation in embryonic chick pigment retina cultured in vitro
Authors: Takeuchi Yoshiko K. , Takeuchi Ikuo K. , Kajishima Takao
Published: June 2005

When the retinal pigment epithelial cells of the chick embryo are transferred to monolayer cultures, they lose their phenotypic trait — melanin granules — after a few days. Within the first 24 hours almost all of the melanosomes and premelanosomes are transformed into the degradative structures of the dense bodies or the melanosome complexes. Then, within a few days, these structures disappear completely from the cytoplasm. Actinomycin D, added to the culture medium during the first four hours, almost completely prevents the transformation of melanosomes and premelanosomes. The inhibition of cell proliferation, caused by the addition of colcemid, does not prevent the transformation, though the time of initiation of transformation is delayed considerably. The mechanisms of the transformation of pigment granules are discussed.
Optimal temperatures for inner‐ear performance in gekkonoid lizards
Authors: Werner Yehudah L.
Published: June 2005

Temperature effects on the cochlear alternating potentials are described in lizards of the Eublepharidae (4 spp. and subspp.), Diplodactylinae (2 spp.), Gekkoninae (7 spp. and subspp.) and Sphaerodactylidae (1 sp.). Pure tones (50–15,000 Hz) were applied to the anaesthetized gecko's external ear. Sound intensity needed for a standard response was plotted (db versus frequency). A total of 249 such sensitivity functions were obtained from 50 animals, at temperatures of 15–40°.

For each species, an optimal sensitivity function is definable by its extreme sensitivity and relative smoothness. This is obtained throughout a specific optimal temperature range. At lower temperatures, the function is less sensitive and its best sensitivity is at a lower frequency. The specific optimal cochlear temperature range resembles the specific ecological temperature preferendum where known. Both are broader in gekkonoid than in iguanid lizards.

The temperature effects on the sensitivity function occur even with aerial or mechanical stimulation at the oval window after middle ear extirpation. Hence they arise in the inner ear. Their magnitude (db/°C) is half that known from auditory nerve potentials.

When accurate auditory data are desired, the specific optimal temperature and its possible seasonal variation require consideration. This increases the need for proper identification of subjects by name and origin, and for monitoring experimental thermal parameters, including pre‐experimental acclimation.
Larval and adult abdominal defects resulting from microcautery of blastoderm staged Drosophila embryos
Authors: Bownes Mary
Published: June 2005

Drosophila embryos were damaged by microcautery at the cellular blastoderm stage at the sites of presumptive histoblasts, identified from fate maps. The resulting adults were analyzed for abnormal abdominal structures in one series, and in two further series the pupal cases of the defective adults which hatched were also checked for irregularities in segmentation of the larva, both dorsally and ventrally. The relationships between the larval segmentation and adult pattern are described. A sample of pupal cases of morphologically normal flies hatching from microcautery were checked and showed that regulation only rarely occurred, i.e., abnormal larvae sometimes produced normal adults.

Both tergite and sternite defects occurred, and duplications of parts of these structures were observed in both cases. In general, abnormal fusions, missing hemi‐segments, and partial deletions were associated with larval defects and were therefore probably the result of damage to larval cells, or both larval cells and histoblasts. Duplications and partial segment deficiencies also resulted from apparantly normal pupal cases and were therefore probably the result of directly damaging the presumptive histoblast cells of the blastoderm. It is suggested that the various nests of histoblasts in each segment act as one morphogenetic field, with larval cells within the field.
Serum thyroxine concentrations in larval and metamorphosing anadromous sea lamprey, Petromyzon marinus L.
Authors: Wright Glenda M. , Youson John H.
Published: June 2005

Thyroxine (T4) concentrations in samples of fresh sera taken from fed and unfed larval (ammocoetes) and metamorphosing anadromous sea lamprey (Petromyzon marinus) were measured by means of radioimmunoassay. T4 levels in unfed ammocoetes after a 1‐month period were not significantly different from those of the fed ammocoetes. Nutritional state of ammocoetes therefore does not seem to affect their serum T4 levels. Serum T4 concentrations decreased abruptly at the onset of metamorphosis and declined to levels observed in spawning adults (Leloup and Hardy, '76; Packard et al., '76) by the middle (stage 3) of metamorphosis. No significant change in serum T4 levels occurred between stage 3 to the end of metamorphosis. The possible significance of the decline in serum T4 levels to the metamorphic event in lamprey is discussed.
The effects of temperature and season of collection on the onset and duration of diapause in embryos of the annual fish Nothobranchius guentheri
Authors: Markofsky Jules , Matias Jonathan R.
Published: June 2005

Annual fish are found in temporary bodies of water in habitats of alternating rainy and dry seasons. The populations survive the dry seasons in the form of embryos encased in the bottom mud. Several genera of annual fish have been reported to exhibit diapause (developmental arrest) at three specific stages of development and it has been proposed that through this adaptation the populations are able to survive the variable durations of the dry seasons. The effects of incubation and spawning temperatures, and season of collection on the onset and duration of diapause in laboratory populations of the annual fish, Nothobranchius guentheri, were studied. At low incubation and spawning temperatures there was a prolongation of Diapause I and Diapause II. In addition, fish spawned at 25°C during the short days of winter produced embryos that entered a prolonged duration of Diapause II, whereas embryos produced during the long days of summer bypassed Diapause II.
Histochemical study of the amphibian digestive tract during normal and thyroxine‐induced metamorphosis. I. Alkaline phosphatase
Authors: Kaltenbach Jane C. , Lipson Marcia J. , Wang Claire H. K.
Published: June 2005

Histochemical patterns of alkaline phosphatase activity were demonstrated in specific regions of the digestive tube in a series of growing and metamorphosing larvae and frogs of Rana pipiens. In growing larvae activity in the mucosal epithelium was intense and sharply localized in the striated border of the duodenum posterior to the bile duct and of the mid‐small intestine. No activity was found in the epithelial lining of the esophagus, stomach (or its glands), duodenum anterior to the bile duct, end of small intestine, or large intestine. Connective tissue and blood vessels throughout the length of the digestive tract displayed moderate activity. As remodeling of the gut began in metamorphosing larvae, the high phosphatase activity in the striated border decreased sharply, but activity in the connective tissue of the entire digestive tract increased substantially. As metamorphosis neared completion and a new mucosal epithelium developed, activity became strong in the striated border throughout the small intestine, including the region anterior to the bile duct and the end‐small intestine. In adult well‐fed frogs activity remained in this location, although in unfed frogs kept in the cold it diminished in the striated border and became prominent in subepithelial blood vessels. Enzyme activity was not detected in connective tissue (excepting random blood vessels) in any region of the frog digestive tract. These histochemical observations represent an overview of the distribution of alkaline phosphatase activity along the length of the digestive tract during larval and adult stages of a single anuran species.
On the buoyancy of the pearly Nautilus
Authors: Ward Peter , Martin Arthur W.
Published: June 2005

Fourteen freshly captured Nautilus macromphalus were weighed in seawater, and all were found to be negatively buoyant (heavier than seawater), with a mean weight of 1.76 g. Maximum rates of cameral liquid removal from chambers artificially filled with seawater were 1.0 ml/chamber/day at the surface. Specimens made artificially buoyant by the removal of cameral fluid, and maintained at 60 m or less, were unable to regain normal, slightly negative buoyancy through admission of new liquid into the emptied chambers via the siphuncle. Specimens maintained at depths of greater than 150 m all showed new cameral liquid in the previously emptied chambers. Because of the relatively slow rate of cameral liquid removal from the chambers, and seeming inability of Nautilu to place cameral liquid into emptied chambers in shallow water, we conclude that the phragnocone‐cameral liquid system is utilized for long term buoyancy adjustments rather than short term changes which might aid vertical ascent or descent.
Actin in mammalian sperm heads
Authors: Clarke G. N. , Yanagimachi R.
Published: June 2005

An actin‐like substance has been detected in the post‐acrosomal region of mammalian spermatozoa by indirect immunofluorescence. The antigen was localized using an anti‐actin antiserum from a patient with active chronic hepatitis. The actin‐like contractile proteins may be important in sperm function and sperm‐egg interactions during fertilization.
A gene necessary for late sperm function in Drosophila melanogaster
Authors: Geer B. W. , Bowman J. T. , Tyl B. T.
Published: June 2005

A male‐sterile mutant, ms(1)7, of Drosophila melanogaster is defective in post‐ejaculatory sperm function. The mutant gene is located at one of at least five male fertility loci in 18F through section 20 of the polytene X‐chromosome. It is proposed that the ms(1)7 + gene product modifies a component of the sperm head. A nearby gene may be functionally related to ms(1)7+.
Limbless: A new genetic mutant in the chick
Authors: Prahlad K. V. , Skala Gerald , Jones Dean G. , Briles W. E.
Published: June 2005

A mutation in the chicken resulting in total amelia is described. Genetic analysis indicates that the limbless condition is due to an autosomal recessive gene. In the limbless embryos the apical ectodermal ridge is lacking. However both the pectoral and pelvic girdles as well as the respiratory and excretory systems are normal. In the affected embryos usually the upper beak is shorter than the lower beak.