bluuebunny/crossref_metadata_2025 huggingface dataset:
Adenosine deaminase phenotypes among sexual and parthenogenetic lizards in the genus Cnemidophorus (teiidae)
Authors: Neaves William B.
Published: June 2005

Electrophoresis of liver homogenates has revealed distinct adenosine deaminase (ADA) phenotypes in each of four sexual species belonging to the Cnemidophorus sexlineatus group. A fifth sexual species, C. tigris, shares one of these phenotypes with a species of the C. sexlineatus group, but is distinguished from this species by other genetic and biochemical characters. Hence, knowledge of ADA phenotypes permits discrimination among each of the five sexual species suspected of involvement in interspecific hybridizations leading to the origin of parthenogenetic Cnemidophorus species. Combinations of two or three ADA phenotypes characteristic of sexual species are found in each parthenogenetic species studied. This finding supports the theory of hybrid origin of parthenogenetic species, while the combination of particular alleles in each parthenogenone permits the implication of specific sexual species in its origin.
Photoperiodic control of antler cycles in deer. II. Alterations in amplitude
Authors: Goss Richard J.
Published: June 2005

Deer native to temperate zones grow new antlers each year in synchrony with the annual photoperiodic cycle. When the amplitude of this cycle is reduced from normal winter and summer solstices (at 42° latitude) of nine and fifteen hours to as little as eleven and one‐half and twelve and one‐half hours (equivalent to about 9° latitude), sika deer still tend to grow antlers on schedule, even when that schedule is accelerated.

Deer exposed to days of constant length for prolonged periods of time fail to replace their antlers when the light:dark ratio is 12L/12D. When held on unchanging short (8L/16D) or long (16/8D; 24L/OD) days, however, they continue with their antler cycles at irregular intervals averaging about 85% of the siderial year.

These results are interpreted in terms of an inherent circannian rhythm, the duration of which can be adapted to the frequency of the prevailing photoperiodicity, but which reverts to approximately a year on constant long or short days and disappears altogether on simulated equatorial photoperiods.
Acid mucopolysaccharide changes in chick hatching muscle
Authors: Klicka John , Edstrom Ronald , Ungar Frank
Published: June 2005

Acid mucopolysaccharide levels in the Musculus complexus (hatching muscle) of the chick embryo progressively increase during the final 96 hours of incubation with the most marked increase occurring on the day of pipping. The significance of these changes in relation to the role this muscle plays in the hatching process remains obscure, but it is suggested that the mucopolysaccharides, together with the large amount of water simultaneously taken up by this tissue, form a spongy muscle mass which serves to cushion the skull when force is applied to the shell during pipping.
Phenogenetics of the eyeless‐Dominant mutant of Drosophila melanogaster. I. Development of the lethal larvae,
Authors: Arking Robert
Published: June 2005

The causal mechanisms underlying the lethality of the eyD lethal homozygotes of D. melanogaster were studied. The phenocritical phase occurred at the onset of metamorphosis. Non‐pupating larvae remained in the third instar for periods of time ranging up to 120 hours after their normal sibs had pupated. By this time they had either died as arrested third instar larvae or else underwent a delayed pupation and then died. No “fourth instar” larvae were observed. Those lethals that did pupate died at a mean gonadal developmental age of 20–36 hours. A distinctive syndrome of morphological abnormalities, characteristic of an aphasic development, was found in the non‐eclosed pupae. Paraldehyde fuchsin staining of normal and lethal animals has indicated that the release of the neurosecretory substances in the lethals may be delayed for at least 36 hours following pupation. Injection of approximately 0.07 μg of α‐ecdysone enabled 94% of the non‐pupating larvae, arrested at the third instar for 72–84 hours after their normal sibs had pupated, to resume development and enter the prepupal or pupal stages. It is suggested that the eyD mutation most likely exerts its lethal effect by adversely affecting the ecdysone titer, thereby creating a hormonal imbalance with manifold effects on the developmental process.
The ear of the chameleon: Chamaeleo höhnelii and Chamaeleo jacksoni
Authors: Wever Ernest Glen
Published: June 2005

The study of the chameleon ear that began with Chamaeleo senegalensis and Chamaeleo quilensis has now been extended to two further species, Chamaeleo höhnelii and Chameleo jacksoni, with results that are different in important respects. As measured in terms of cochlear potentials, the two species of the present study show definitely poorer sensitivity to aerial sounds. Also their responsiveness to these sounds is not made much worse by severing the columella, an observation that stands in contrast with the serious impairment that this operation produces in C. senegalensis and C. quilensis.

The explanation lies in a difference between the sound receptive mechanisms in the two groups. In the species examined earlier a substitute tympanic membrane was found: beneath the surface at the side of the head is a diaphragm formed by a thin plate of the pterygoid bone and a membrane extending its surface to the border of the quadrate bone. In addition there is a branch process (anterior process) of the extracolumella that attaches to the middle of this pterygoid plate, and transmits the movements made by the plate in response to sounds to the stapedial footplate in the oval window. In C. höhnelii and C. jacksoni this anterior process is lacking, and the pterygoid plate cannot function as a sound receptive surface.
Metamorphosis of imaginal disks of the housefly: Evagination of transplanted disks
Authors: Bhaskaran G. , Sivasubramanian P.
Published: June 2005

A new technique for transplanting imaginal disks of the housefly is described. When prepupal disks are transplanted superficially (surface transplantation) just beneath the puparium in early prepupal hosts, they evaginate synchronously with the host's organs and differentiate normally like the disks developing in situ. Histological evidence indicates that cells from the peripheral region of the disks migrate and join the epidermis of the host. This facilitates continuation of morphogenetic events culminating in eversion of the transplant. The significance of the cellular contact with epidermal cells of the host is discussed.

A well developed nerve from the transplanted leg joins the thoraco‐abdominal ganglion of the host. Flexion of the terminal leg segments indicates the presence of motor fibers innervating muscles in the leg.

Disks from late third instar larvae and young prepupae evaginate whereas disks from younger third instar larvae fail to evaginate when surface transplanted. Disks, from all types of donors, cultured in adult abdomens fail to evaginate when retransplanted in prepupae. These and other results suggest that hormones may induce or inhibit morphogenetic cell movement in imaginal disks.
Postural control of shell position by the abdomen of the hermit crab, Pagurus pollicarus. I. Morphology of the superficial muscles and their nerves
Authors: Chapple William D.
Published: June 2005

As in other decapod crustacea, the muscles of the hermit crab abdomen are divided into a central mass of muscle, active during the escape response, and a superficial layer of muscles which is responsible for the normal postural movements of the abdomen. The ventral superficial muscles consist of three layers, a mesial layer of longitudinal fibers, and two distal layers of circular muscle. The longitudinal muscles are thicker on the right side and are divided into three longitudinal strips each innervated by a single excitor motoneuron. Six motor axons innervate the ventral superficial muscles on each side — those on the right are larger than those on the left. Also occurring in the third ganglionic root is a group of fine axons believed to be branches of the motoneurons. There does not appear to be any relationship between the size of the motoneuron and the amount of muscle innervated.
Neurotrophic dependence of the lateral‐line sensory organs of the newt, Triturus viridescens
Authors: Jones Dorothy P. , Singer Marcus
Published: June 2005

The neurotrophic influence on the morphological maintenance of the lateral‐line sensory organs has been studied in the adult newt, Triturus viridescens, under various conditions of denervation. Results show little if any atrophic and degenerative changes during two months following resection of the lateral‐line nerve or the incident spinal nerves. However, if both are destroyed, thus rendering the total environs of the organs nerveless, atrophy and degeneration are advanced within a two‐month period and, indeed, are evident within three weeks. The results favor the idea of neurotrophic control of the lateral‐line sensory organs in amphibians. The results are discussed against the background of past controversies and speculations on the neurotrophic phenomenon. Various control experiments including heterotopic transplantation of the sensory organs are also reported.
Temporal changes in protein synthesis by mouse blastocysts transferred to ovariectomized recipients
Authors: Weitlauf Harry M.
Published: June 2005

Protein synthesis in mouse blastocysts, as inferred from the incorporation of 35S methionine in vivo, begins on day 5 of pregnancy (day 1 = the day of vaginal plug formation). The activation of protein synthesis is hormone dependent and does not occur in the absence of either estrogen or progesterone. However, previously stimulated eggs are capable of incorporating 35S methionine immediately after being transferred to ovariectomized recipients. The hormones may affect the blastocysts in two possible ways: (1) they may be responsible for the initial activation and thereafter have little or no effect; or (2) they may be necessary to both activate the blastocysts and to maintain them in an active state.

To determine which of these possibilities is correct active blastocysts were recovered from intact donors on day 5 of pregnancy and transferred to the uteri of ovariectomized females. 35S methionine was given at progressively longer intervals thereafter and the blastocysts were recovered and prepared for radioautography.

It was found that 35S methionine incorporation by the blastocysts decreased and finally stopped after prolonged exposure to the uteri of ovariectomized recipients. The depression was not caused by damage to the embryos; rather they simply became dormant.
On the application of immunological techniques in geographic group studies of Atlantic sea herring, Clupea harengus II. Herring serum analysis by gel diffusion
Authors: DiCapua Richard A.
Published: June 2005

The sera of Atlantic sea herring, collected from 13 contiguous oceanic locations, were assayed by gel (double) diffusion for precipitinogen differences. An immune serum (rabbit) against the sera of each location was required. Gel diffusion patterns characteristic of specific geographic origins of herring sera were not detected. Immune serum aliquots were therefore individually neutralized with one of a series of dilutions of herring serum from the various geographic locations prior to diffusion (the use of undiluted serum results in complete precipitin neutralization regardless of its origin). The neutralization capacity of origin‐separate precipitinogens appears to be related to the geographical distance separating the origins of immunizing and neutralizing sera. Sera of unknown origins, providing they originate from the overall area sampled, can be related to sera of specific origins by comparison of their neutralization capacities. The gel diffusion results are in agreement with previously reported immunoelectrophoretic data (DiCapua, 1966) and are consistent regardless of sex, pool size constituting the sample or collection date. The serological relationship of the five dominant clupeoid species is examined.
An electron microscopic study of chordamesoderm‐neurectoderm association in gastrulae of a toad, Xenopus laevis
Authors: Kelley Robert O.
Published: June 2005

Gastrulae from South African Clawed Toads, Xenopus laevis, were fixed in phosphate buffered glutaraldehyde, postfixed with Os O4 and prepared for electron microscopy. Mesodermal cells did not contact cells of the ectodermal layer. Furthermore, unexpected quantities of extracellular material filled the space between layers during early stages of gastrulation. Extracellular material consisted of glycogen, ribonucleoprotein particles, and fibrillar material, similar to material present in lobes of mesodermal cells during the first half of gastrulation. Mesodermal lobes and extracellular materials were also present in ectodermal sandwiches incubated with mesoderm for three hours, but were absent in explants cultured less than three hours. Extracellular materials were also absent in ectodermal sandwiches cultured with presumptive epidermis (non‐inducing cells) for three hours. Ectodermal cells appear to incorporate fibrillar material from the interspace by pinocytosis during late stages of gastrulation. Autoradiographs suggest that labeled RNA is not transferred to ectoderm during gastrulation, but is involved in protein synthesis within mesodermal cells. The product of this synthesis might be visualized as extracellular fibrillar material.
An immunochemical study of the surfaces of sponge cells
Authors: Maclennan Alastair P.
Published: June 2005

Cells from sponges of six different species when injected into rabbits induced the formation of specific agglutinating antibodies. Cells of each species were shown by cross‐agglutination and cross‐absorption tests to possess species‐specific antigenic determinants on their surfaces, and the observed cross reactions between species were in general accord with taxonomic relationships ascribed on more conventional criteria. Preparations containing complex heteropolysaccharides together with peptide were obtained by extraction of sponges with trichloroacetic acid and were shown to possess the serological specificities of the sponge cell surfaces. These preparations, from each of the six species, sensitized fowl erythrocytes to agglutination by homologous sponge cell antisera. The titers of cross hemagglutination obtained with an individual antiserum and variously sensitized erythrocytes were paralleled by the titers obtained in direct agglutination of sponge cells, indicating that the antigenic groups responsible for hemagglutination were similar to those present on the sponge cell surface and dominating its serological reactions. The isolated polysaccharide‐containing substances precipitated agglutinating antibodies and were themselves antigenic in rabbits. Chemical and serological analysis of a purified polysaccharide obtained from crude material by ion‐exchange chromatography, together with other lines of evidence, suggested that carbohydrate rather than peptide antigenic specificities underlay the serological behaviour of the sponge cell surface.

The cell surface specificities detected serologically appeared not to be due to sensitization of sponge cells by intracellular substances liberated during the preparation of cell suspensions from intact sponge. Certain pairs of the sponges examined showed specific cellular reaggregation but the species specificity exhibited did not correlate in any simple manner with the demonstrated antigenic relationships of the species. The serological results are discussed in relation to the various postulated mechanisms of specific reaggregation.
Nucleic acid synthesis in preimplantation rabbit embryos. I. Quantitative aspects, relationship to early morphogenesis and protein synthesis
Authors: Manes Cole
Published: June 2005

The ability of rabbit embryos to incorporate tritiated uridine and thymidine into acid‐insoluble material in vitro has been quantitated by liquid scintillation counting at daily intervals throughout the preimplantation period. The ribonucleic acid content of the embryos has been determined by the orcinol reaction. It is shown that, in spite of a low level of Actinomycin D‐sensitive uridine incorporation during cleavage, there is no net synthesis of ribonucleic acid until immediately prior to blastocyst formation. The acceleration of ribonucleic acid synthesis which occurs at that time precedes, by some 36 hours, the acceleration of protein synthesis. This finding is discussed from the standpoint of genetic expression in the preimplantation rabbit embryo, and with reference to the possibilities for post‐transcriptional control of protein synthesis.
The implantation of blastocysts in the Russian steppe lemming (Lagurus lagurus)
Authors: Aldeen K. Mohi , Finn C. A.
Published: June 2005

Implantation in the lemming occurs between the sixth and seventh days of pregnancy and is accompanied by decidualization of the stroma. The blastocyst appears to pass through the epithelium as in interstitial implantation. Alkaline phosphatase is present in the stroma along the length of the uterus before the start of implantation but becomes more intense in decidualized areas following attachment of the blastocyst.

Blastocytes do not implant if animals are ovariectomized on the fourth day of pregnancy and progesterone alone is given but will implant if a small amount of oestradiol is given in addition to progesterone.

A decidual cell reaction can be induced by the intrauterine injection of oil into animals mated with a vasectomized male; this reaction always occurs on the antimesometrial side of the uterus.
Control of prolactin release and its role in color change in the teleost Gillichthys mirabilis
Authors: Sage M.
Published: June 2005

The degree of pigment dispersal in the xanthophores and melanophores of Gillichthys mirabilis matched the animal to its background. Hypophysectomy did not affect the melanophores, which appear to be under nervous control, but did cause concentration of the pigment in the xanthophores so that the fish could no longer adapt to a yellow background. Acetyl choline had no effect on the pigment cells but epinephrine concentrated the pigment in the melanophores. Prolactin and high doses of ACTH dispersed the pigment in the xanthophores; the main effect of ACTH was indirect and probably due to stimulation of the interrenal tissue. Cortisol dispersed pigment in the xanthophores and concentrated it in the melanophores. β‐MSH also had an indirect effect in dispersing pigment in the xanthophores. Metyrapone reduced the indirect effect of β‐MSH and ACTH but had no effect on the yellowing of fish to match a yellow background. Thus prolactin, rather than the other hormones, appears to be involved in the normal response to a yellow background. The subcutaneous implantation of a single pituitary provided sufficient hormone to affect the overlying xanthophores. Reserpine resulted in pigment dispersal in the xanthophores of intact Gillichthys but had no effect in hypophysectomized fish. This suggests that the release of prolactin is normally controlled by an inhibitory factor from the brain.
Behavioral reflexes in Rana catesbeiana and Rana clamitans with large skin grafts
Authors: Baker Robert E.
Published: June 2005

Large pieces of skin completely encircling the abdomen in tadpoles of Rana catesbeiana and Rana clamitans were removed, rotated through 180° and replaced. During metamorphosis animals of both species developed fore‐ and hindlimb reflex behavior in response to stimulation of the body and graft. These responses remained consistently normal throughout the experimental period and did not become maladaptive as was found to occur in a related species, Rana pipiens.

The cutaneous receptive fields were mapped electrophysiologically in control and skin‐grafted Rana catesbeiana frogs and in one skin‐grafted Rana clamitans. The sizes and shapes of the receptive fields were similar to those previously reported for Rana pipiens. Unlike the receptive fields in Rana pipiens and Rana clamitans, the receptive fields examined in Rana catesbeiana readily overlapped the borders of the skin graft, innervating both normal and grafted skin.

Reasons for prolonged normal behavior and cutaneous receptive field overlap in skin‐grafted Rana catesbeiana are discussed.
A re‐investigation of evidence for cholinergic neuromuscular transmission in insects
Authors: Faeder Isabelle R. , O'Brien Richard D. , Salpeter Miriam M.
Published: June 2005

Although the bulk of recent evidence suggests that acetylcholine is not an excitatory transmitter at insect neuromuscular junctions, certain anomalies exist which required re‐evaluation. Several drugs affecting cholinergic transmission were studied in isolated nerve muscle preparations of adult Periplaneta americana, Gromphadorhina portentosa and Locusta migratoria and larval trunk muscle of Samia cecropia. None of the drugs studied appears to affect neuromuscular transmission in these insects. However, eserine, nicotine, and nicotine analogs produce central effects, and several drugs including succinylcholine, nicotine, nicotine analogs and eserine appear to affect motor axons at high concentrations. ACh produced no effect on isolated leg preparations of cockroaches, but did produce a transient increase of kick force in jumping leg preparations of newly molted locusts. ACh (2.5 × 10−8 − 2.5 × 10−4 M) had no effect on nerve muscle preparations of Gromphadorhina up to 20 days after nerve section, although spontaneous mechanical activity and deterioration of neuromuscular junctions were observed during this period. All preparations gave contractures to L‐glutamate (pH 7.0); the threshold (2.5 × 10−4 M) for this response did not change after denervation.
Biochemical genetics of Tribolium. I. The foundation population
Authors: Gall G. A. E.
Published: June 2005

The life cycle characteristics of Tribolium castaneum for body weight, RNA Concentration, soluble protein concentration and the rates of four dehydrogenases were examined using an outbred wild type stock. Average egg weight decreased until hatching occurred. Larval growth showed an exponential pattern over time reaching a maximum body size just prior to pupation (14 days). Adults increased in size only slightly.

Maximum RNA and soluble protein concentrations were observed at 9 and 14 days, respectively, and decreased rapidly thereafter. Activities of glucose‐6‐phosphate, 6‐phosphogluconate, lactate and NADP‐linked isocitrate dehydrogenases also were maximal at 14 days, the time of most rapid growth rate. The data suggest a definite relational pattern between growth rate, RNA and protein synthesis at least during larval development.
Anal fin regeneration in thiouracil‐treated guppies
Authors: Hopper Arthur F. , Wallace Edith
Published: June 2005

Male guppies were kept in a solution of 0.03% thiouracil for 45 days. At this time the gonopodium was cut back and then allowed to regenerate while the fish were maintained in one of the following solutions: (1) thiouracil, (2) aged tap water, (3) 0.01% thyroid powder, (4) 1:500,000 ethynyl testosterone, (5) ethynyl testosterone and thyroid powder, (6) ethynyl testosterone and thiouracil, (7) thyroid powder and thiouracil.

Regeneration was greatly inhibited in solutions 1, 2, 5 and 7. Regeneration was normal or almost so in solutions 3, 4 and 6. It is concluded that the thiouracil‐induced inhibition of regeneration of the gonopodium of the guppy is due to the effect of thiouracil on the formation or release of testicular hormones.
Temporal effects of hormones on DNA synthesis in mouse mammary gland in vitro
Authors: El‐Darwish I. , Rivera E. M.
Published: June 2005

Mammary explants from midpregnant mice were cultured for one to five days in chemically‐defined medium containing various combinations of insulin, prolactin, and corticosterone. The influence of these hormones on DNA content and synthesis was assessed at the end of one, two, three, and five days. Explants from each culture were also examined histologically for survival and secretory responses.

Insulin was primarily responsible for the stimulation of DNA synthesis. Its peak activity occurred on the first day of culture. After this time, prolactin and corticosterone interact with the tissue to maintain the insulin stimulation; prolactin's effect is manifested before that of corticosterone. The hormones in the temporal order of their effect on mammary DNA in vitro thus appear to be: insulin, prolactin, corticosterone. The histological findings indicate that secretory development occurs subsequent to cell proliferation.
Local metamorphic action of thyroxine analogues in Rana pipiens larvae,
Authors: Kaltenbach Jane Couffer
Published: June 2005

To determine whether or not various thyroxine analogues accelerate metamorphosis by acting directly upon target organs, analogue‐cholesterol pellets were prepared and implanted into the dorsal tail fins of Rana pipiens larvae. Many analogue implants caused localized fin resorption, a response attributed to the direct action of the analogue upon the fin. Analogues with acetic or propionic acid side chains or with an isopropyl group but no iodine atoms in the β ring were effective in lower concentrations than was thyroxine; on this basis, the most active compounds were triiodothyropropionic acid and isopropyldiiodothyronine. Fin resorption was not induced by implants of diiodophenoxyacetic acids or of dihalogenated methoxythyranilines. Yet, intraorbital implants of these compounds did stimulate glandular development in the skin dorsal to the eye (a region with a lower threshold of response to thyroxine than the tail fin). The causation of local metamorphic responses, either in the tail fin or in the orbital region, by various thyroxine analogues indicates the direct action of such compounds upon peripheral tissues of the tadpole.
Ultrastructure of rat mammary‐gland anlagen in vivo and after culture with hormones
Authors: Ceriani Roberto , Pitelka Dorothy R. , Bern Howard A. , Colley Vickie B.
Published: June 2005

Mammary gland anlagen from the 17‐day fetal rat were grown for six and nine days in organ culture in basal (Waymouth's agar) nutrient medium only and with added insulin, insulin and prolactin, or insulin, prolactin, and aldosterone. Prior work has shown that the three‐hormone combination is most effective in stimulating histologic differentiation and the synthesis of a casein‐like material. Cultured explants from each group were examined by electron microscopy and compared with 17‐day anlagen before culture and with the mammary gland of the newborn female rat. The 17‐day anlage is a solid mass of cells, surrounded by a basal lamina and a partially oriented sheath of mesenchyme cells; ultrastructure of the epithelial cells shows the characteristics of fetal tissue. At birth, the normal mammary gland consists of an extensively branching system of ductules with continuous lumina and a well developed sheath of connective tissue. Luminal surfaces of epithelial cells bear numerous microvilli and are ringed by continuous belts of tight junctions. Fat droplets are present in cells and lumina and the Golgi apparatus is abundant but not visibly active in protein secretion; rough endoplasmic reticulum is present in moderate quantity and occasionally is distended with low‐density, homogeneous content. Organ culture without hormones resulted in epithelial cell proliferation; however, the basal lamina disappeared, no connective‐tissue sheath developed, and the epithelial mass showed no organized growth pattern. Some small, true lumina appeared within the cell mass. With insulin added, the anlagen ramified moderately and formed true lumina that were distinct but often discontinuous; the enveloping connective and adipose tissues were well developed. Epithelial cells showed little organellar differentiation but contained many fat droplets and abundant glycogen. In the presence of insulin and prolactin, ductal organization was much improved, whereas organellar differentiation within epithelial cells was only slightly better than with insulin alone. With the three‐hormone combination, histologic organization and ultrastructural differentiation attained levels similar to those in the gland of the newborn rat; in addition, the Golgi complex in some cells was conspicuously active and many Golgi vesicles contained condensed material similar to the protein secretion products seen in pregnant and lactating mammary glands.
Changes in chromosomal DNA replication patterns in developing frog embryos
Authors: Stambrook P. J. , Flickinger R. A.
Published: June 2005

Continuous exposure of embryonic explants to thymidine‐H3 was used to determine patterns of late‐replicating DNA synthesis, i.e. DNA synthesized during the last quarter of the S period, in chromosomes from different germ layers of developing frog embryos (Rana pipiens). Autoradiographic localization of silver grains over chromosomes 1, 7 and 8, as well as unkaryotyped chromosomes, revealed that patterns of late‐replicating DNA are similar in determined cells that will undergo different pathways of differentiation. In undetermined early gastrula cells and in differentiated tailbud dorsal axial cells (nerve tube, somites and notochord) more sites of DNA synthesis were late‐replicating in chromosomes 1, 7 and 8 and in unkaryotyped chromosomes than in cells of the neural plate‐dorsal mesoderm of neurulae where differentiation is occurring and in neurula endoderm where determination is taking place.
The forces involved in water uptake by the rabbit blastocyst
Authors: Tuft Peter H. , Böving Bent G.
Published: June 2005

The freezing point depression (ΔTf) of the plasma, uterine fluid and the fluid in the blastocyst cavity have been measured in pregnant rabbits at 4, 5, 6, 7 and 8 days post coitum. The sign and magnitude of the chemical potential gradients of water between the different compartments have been calculated from the mean values for the ΔTf. It is concluded that these gradients cannot account for the observed net water flows and that energy‐coupled processes must be involved. The energy available from respiration is far more than would be required for such energy‐coupled water flow.
Catalytic properties of the lactate dehydrogenase isozyme “X” from mouse testis
Authors: Battellino Luis J. , Blanco Antonio
Published: June 2005

Lactate dehydrogenase (LDH) isozyme 1 (B4), 5 (A4), and “X” (Testis or Sperm type) have been partially purified from mouse tissues.

The following studies were carried out on the three isozymes: Km and optimum substrate concentration for pyruvate, α‐oxo‐butyrate, α‐oxo‐valerate, lactate, α‐OH‐butyrate, and α‐OH‐valerate, inhibition by substrate and product, effect of malate, N‐(4‐carboxy‐2‐hydroxyphenyl) maleimide, some citric acid cycle metabolites, urea, trypsin and pH.

The mouse testicular LDH isozyme clearly differs from the common lactate dehydrogenases and from the tesficular isozymes from other species. It shows distinct sensitivity to inhibition by substrate or product whether the direct (pyruvate → lactate) or reverse reactions are studied. There is no effect of increasing concentrations of pyruvate or lactate on the direct reaction, while a clear inhibition by lactate or pyruvate is demonstrated on the reverse reaction. Citric acid cycle metabolites, specially malate and succinate, inhibit the direct reaction catalyzed by the “X” isozyme.

These peculiar characteristics suggest a high degree of specialization for the principal testicular isozyme of lactate dehydrogenase.
Morphological and biophysical identification of fibrous proteins in the amniote epidermis
Authors: Baden H. P. , Maderson P. F. A.
Published: June 2005

Epidermal material from a variety of reptilian species, avian and mammalian scales have been examined by standard histological and x‐ray diffraction techniques. It has been found that morphologic and/or tinctorial properties are not good criteria for the identification of specific fibrous protein types. The distribution of fibrous protein types in reptilian epidermal material is very variable, especially in turtles. Lepidosaurian reptiles (the tuatara, snakes and lizards) are unique in showing an alternating vertical distribution of feather and α‐type proteins over the entire body surface. The protein distribution in crocodilian scales resembles exactly that found on avian scales. Mammals only possess the α‐type protein whatever the nature of the epidermal structure of modification.
Effects of temperature, photoperiod, and hibernation on the testes of golden hamsters
Authors: Frehn John L. , Liu Chung‐Ching
Published: June 2005

The effects of hibernation and 1, 2, 4, 8, 12, 16, and 20 weeks of cold‐exposure (5 ± 1° C) were studied on the testes of 100 adult, male hamsters (Mesocrietus auratus, Waterhouse), having initial body weights of 80 to 100 gm. Half of these animals were maintained on an eight‐hour photoperiod and half on a 14‐hour photoperiod. Control animals, at both photoperiods, were kept at 25 ± 1° C. At the time of autopsy, the wet weights of the testes were determined and the tissue was prepared for quantitative histological evaluation (diameter of the seminiferous tubules and spermatogenic activity). In animals kept at 25° C and 14 hours of light, the testes remained unchanged. With eight hours of light at the same temperature, however, the testes: (1) were unaffected for four weeks; (2) exhibited a 90% loss in wet weight at eight weeks; and (3) recovered to about 66% of the initial level at 12 and 20 weeks. In cold‐exposed hamsters, the testes decreased rapidly in activity between two to four weeks, reaching the lowest weight at eight weeks. Those cold‐exposed animals on 14 hours of light returned to the control level by 16 weeks, but those on eight hours showed only slight recovery. The testes of the 14‐hour light, cold‐exposed animals were larger than those of the eight‐hour light, cold‐exposed animals at each week tested. Only with the 14‐hour photoperiod were the testes of the hibernators significantly smaller than those of the cold‐exposed non‐hibernators.
Partial sex reversal in adult axolotls developing from cold‐treated eggs
Authors: Brunst V. V.
Published: June 2005

Of 12 adult (4‐year‐old) axolotls (Siredon mexicanum) develoing from cold‐treated eggs, three were originally male, and the other nine were originally female. Only two of the animals, one male and one female, were normal. The second male was underdeveloped, with very small testes and abortive development of sex cells, which included only spermatogonia. The third male was greatly underdeveloped, with vestigial testes, complete degeneration of all germ cells, and entire absence of cloacal glands.

The remaining eight females were greatly underdeveloped, with ovaries of almost microscopic size and partial sex reversal. In three of these females, only male cells could be observed, and the oviducts were very much diminished. In the other five females, the sexual glands were vestiges of hermaphrodite glands, with cells of both sexes (oogonia and spermatogonia) close together.

The chief abnormalities observed in the great majority of the animals, partial sex reversal and development of hermaphrodite sex glands, were evidently due to triploidy developing as a result of cold treatment of the eggs. The normal male and female were most likely diploid. The under‐developed male with only spermatogonia was probably triploid, and the male with complete degeneration of the germ cells could have been triploid. All of the females with sex reversal were undoubtedly triploid.
An autoradiographic study of sperm exchange and storage in a sea hare, Phyllaplysia taylori, a hermaphroditic gastropod (Opisthobranchia: Anaspidea)
Authors: Beeman Robert D.
Published: June 2005

Tritiated thymidine autoradiography was used to distinguish exogenous from endogenous sperm and to determine the translocations of labeled sperm within the simultaneously hermaphroditic, reciprocally copulating gastropod Phyllaplysia taylori. Heavily labeled sperm start leaving the ovotestis within 14 days after injection of H3‐thymidine. These endogenous sperm are stored, evidently less than 20 days, in the ampulla prior to copulation. During copulation the endogenous sperm are tightly bound to one another by extracellular material forming a seminal strand. This seminal strand is moved by ciliary action along the spermoviduct fold and genital groove to the tip of the extended penis. As the seminal strand issues from the tip of the labeled animal's penis into the copulatory duct of an unlabeled mate, the extracellular material of the strand dissolves, releasing the now exogenous sperm (some of which are labeled). Most of the labeled exogenous sperm are found in the seminal receptacle within two hours after copulation. Within five hours some of these sperm have become oriented with their heads buried into the receptacle lining. Surplus exogenous sperm flow into the copulatory bursa where they are destroyed.
An estradiol mitotic rate inhibiting effect in the müllerian epithelium in neonatal mice
Authors: Forsberg John‐Gunnar
Published: June 2005

Beginning within 24 hours after birth, young mice were given daily subcutaneous injections of 5 μg estradiol‐17β in olive oil. The mice were sacrificed at varying times; six hours before death, they were given a subcutaneous injection of colchicine. The mitotic rate was studied in the epithelium in the uterine horns, uterine cervix, and müllerian vagina. Eighteen hours after the first estradiol injection, the mitotic rate was increased in the uterine epithelium, but decreased in the cervical and müllerian vaginal epithelium compared with the controls. At a continued treatment with estradiol, the mitotic rate values decreased to a level somewhat below the control level in the uterine horns; in the uterine cervix and müllerian vagina the mitotic rate decreased to very low values, significantly lower than in the corresponding regions in the controls. The mechanisms behind this mitotic rate inhibition as well as its consequences are discussed.
Temperature effects on cortical characteristics of Tetrahymena
Authors: Nanney D. L.
Published: June 2005

Cortical characteristics of new strains of Tetrahymena pyriformis of syngens 1 and 7, grown at 15°, 25° and 30°C, are compared. Although distinctions can be made in some cases, the magnitude of the difference is very small. This result suggests that natural selection is perceptive to cytogeometric details, per se, as well as sensitive to differences in the anatomy of structural molecules.
Effects of stimulation on the duration of lung ventilation in quail fetuses
Authors: Vince Margaret A. , Cheng R. C. H.
Published: June 2005

Fetuses of the bobwhite and Japanese quail were incubated for the last three days before hatching under four different conditions of stimulation: in isolation, in contact with two eggs given 24 hours more incubation, in contact with two eggs given the same amount of incubation, and in contact with two eggs given 24 hours less incubation. At the same time recordings were made of sounds produced by the experimental egg, and its respiratory movements. Measurements were then made for each experimental egg of (1) the time between the beginning of lung ventilation and the beginning of regular loud clicking, (2) the time between the beginning of regular loud clicking and hatching, and (3) the time between the beginning of lung ventilation and hatching. The two species differed slightly in that contact with other eggs reduced the duration of lung ventilation in the Japanese quail although not in the bobwhite quail; however, in both species lung ventilation varied in length according to the developmental age of the stimulating eggs. The most marked effects were obtained during the silent period of breathing before the eggs began to click. Thus the fetuses of both species apparently need to click for a definite period of time before hatching.
The DNase activities of the mouse
Authors: Ball William D. , Rutter William J.
Published: June 2005

Several tissues of the mouse contain neutral DNase activity, as well as the acid DNase found in lysosomes. The mouse pancreas was found to have very low levels of neutral DNase I activity, in contrast to the high levels of DNase I measurable in bovine pancreas.

On the other hand, the mouse parotid salivary gland produces large amounts of DNase I which is secreted into the saliva.

The parotid DNase can be distinguished from the neutral DNase found in the liver on the basis of acid‐ and heat‐stability, and from the mouse pancreas DNase I on the basis of acid‐stability.

The mouse parotid DNase I is similar to the beef pancreas DNase I in certain of its properties, but shows a distinctly different band pattern on zonal electrophoresis.

It is suggested that the parotid DNase I, like the pancreatic enzymes, is a cell‐specific molecule.
Lens development. V. Histological analysis of the mechanism of lens reconstitution from implants of lens epithelium
Authors: Coulombre Jane L. , Coulombre Alfred J.
Published: June 2005

A piece of five‐day embryonic lens epithelium was implanted in place of the right lens in each of 89 five‐day‐old chick embryos. The steps in the reconstitution of whole lenses from these grafts were identified by histologic analysis. Immediately following the implantation of the lens epithelium large numbers of cells came out of the anticapsular surface. Many of these died. Some of the survivors adhered in groups to the anticapsular surface of the implant. The cut edges of the implant became reflected so that the capsular surface was bent convexly. The reflected epithelium joined the groups of cells adhering to the anticapsular surface of the implant to form a flattened vesicle. The Golgi apparatuses of these cells lay at the anticapsular poles. The basal (capsular) poles of the cells always came to lie outermost regardless of the initial orientation of the implant. In time the vesicle filled the orifice of the eye cup and the reconstituted lens vesicle became invested externally by a continuous sheet of lens capsule. The cells in the wall of the vesicle that lay toward the vitreous body elongated to form lens fibers. A lens equatorial zone appeared facing the edge of the eye cup regardless of the orientation that had been given the implant initially. Thus, all of the reconstituted lenses were properly oriented in the eye.
The production of congenital defects in rats using antisera
Authors: Barrow Mark V. , Taylor W. Jape
Published: June 2005

Pregnant Long‐Evans rats were injected intravenously with antisera to adult kidney, placenta, lung, heart, fetal kidney and fetal thymus on various days of gestation in doses from 1 to 3 ml/100 gm of rat. Control animals showed a resorption rate of 6.6% with a malformation rate of 2.6%.

Antisera to adult kidney and placenta given on the ninth, tenth and eleventh gestational days decreased fetal weights, increased resorption rates to greater than 50% and resulted in a malformation rate of 75% or greater. Malformations were observed in most organ systems depending on the day the antiserum was injected. Antisera to fetal kidney and adult lung produced similar responses but larger doses were required while antisera to adult heart and fetal thymus tissues demonstrated little effect. Purified antisera (gamma G) and pepsin digested gamma G evoked a teratogenic response. Antiserum to glomerular basement membrane was also teratogenic.

These results support the concept that the mechanism of action of teratogenic antisera is an interference with yolk sac transport by adversely affecting the basement membrane of the yolk sac primarily and indirectly producing malformations.
Inhibition of pupation due to crowding in some tenebrionid beetles
Authors: Tschinkel Walter R. , Willson Clyde D.
Published: June 2005

Pupation of mature larvae of several species of tenebrionid beetles is inhibited by crowding. The magnitude of the inhibition varies according to species. The primary factor causing this inhibition is the mechanical stimulation resulting from inter‐larval contacts. Cannibalism of prepupae, pupae and teneral adults is discussed as the probable chief factor responsible for the evolution of the inhibitory effect of crowding.
The origin and possible genetic control of new, stable pigment patterns in the poeciliid fish Xiphophorus maculatus
Authors: Kallman Klaus D. , Schreibman Martin P.
Published: June 2005

X. maculatus is polymorphic for sex‐linked macromelanophore patterns. Fish of different river systems exhibit identical markings, but they have a different genetic basis. The macromelanophore factors give rise to a population or species‐specific pattern only within their own gene pool. Crosses involving XsdYsr males of the Jamapa stock (Jp) gave rise to 3305 progeny — all but one either Sd or Sr. In the exceptional male Sd (spotted‐dorsal) became linked to Sr (stripe‐sided), SrSd. The dorsal fin of this fish and all of its SrSd descendants (5 generations) was almost solid black and heavy spotting was present in the caudal fin. There was no change in expression of Sr. Jp fish with Xsd Ysr, by comparison, possess from one to six well defined spots in the dorsal fin and a clear caudal fin. After introduction into the Hondo stock of X. maculatus Sd of Jp exhibits zero penetrance; the expression of Sd linked to Sr becomes greatly reduced. Thus the changes in gene expression go in the same direction. However, Sd and SrSd behave differently after introgression into X. couchianus. Sd is completely suppressed while Sd linked to Sr gives rise to melanotic and melanomatous dorsal and caudal fins. A similar alteration in gene expression towards a more extreme phenotype has also been observed among the offspring of a Jp Xsp Ysr male in which Sp and Sr became apparently linked. It is postulated that a modifier is closely linked to the macromelanophore factor that regulates its expression. The new phenotype is due to the separation of the two genetic elements. According to this view the phenotype that is expressed when a macromelanophore gene is introduced into a foreign genotype, is primarily determined by the modifier.
The strategy of tail‐autotomy in the Ground Skink, Lygosoma laterale
Authors: Clark Donald R.
Published: June 2005

The adaptation of tail‐autotomy is paradoxical in lizards which utilize the tail as a major fat‐storage organ, because high rates of tail‐loss are normal and because surrender of large fat reserves seems to amount to selective pressure favoring predation on such lizards. Experimental results demonstrate the existence of ta behavioral mechanism in Lygosoma laterale consisting of return by the lizard to where its tail was lost, a strong ingestion response to an inanimate automized tail, and movements by the autotomized tail which make its capture less likely. Laboratory evidence includes rates of ingestion of autotomized tails averaging nearly 40% for five species of skinks. This contrasts with rates averaging 3.4% for two iguanid lizards in which fat reserves are not stored in the tail. Tests with free‐ranging L. laterale show that ingestion occurs in nature. Additional laboratory experiments quantitatively demonstrate escape behavior by tails of L. laterale. The results confirm a behavioral mechanism in L. laterale which compensates for the ready autotomy of major fat reserves. At the same time, two divergent evolutionary strategies of adaptation of the autotomic tail are defined.