bluuebunny/crossref_metadata_2025 huggingface dataset:
A quantitative study of the peripheral nerve supply in the tadpole tail
Authors: Simpson S. B. , Skirnyk Jarema
Published: June 2005

The anuran tadpole tail is capable of regenerating in the absence of the spinal cord. This is in contrast to urodeles and lizards that require the spinal cord for normal tail regeneration. Quantitation of peripheral nerves in the Rana clamitans tadpole tail reveals an average of 6.9 nerve fibers per unit area of soft tissue. This value falls short of the threshold nerve requirement established for regeneration of the Triturus limb. However, when nerve fiber size is taken into consideration, we find that the axoplasm area per unit area of soft tissue exceeds the threshold requirement for limb regeneration in Triturus. When judged against this standard, regeneration of the tadpole tail in the absence of the spinal cord can be explained on the basis of a sufficient neurotrophic contribution made by the peripheral nerves alone.
Influence of hypophysectomy and starvation on blood glucose levels in the newt, notophthalmus viridescens
Authors: Connelly Thomas G. , Goldstein Aida M. , Yamada Tuneo
Published: June 2005

Blood glucose and liver glycogen levels were determined in hypophysectomized, sham‐operated and unoperated control animals all of which had been starved for 10–15 days. The results show that starvation causes a significant decrease in newt blood glucose and that this decrease is not enhanced by hypophysectomy or sham‐operation during a 15‐day period. These data indicate that effects of short periods of hypophysectomy on regenerating tissues are probably not due to a drop in available carbohydrate. However, the data do not indicate what the possible effects of long‐term hypophysectomy on blood glucose would be.
Glycogen synthetase and phosphorylase in developing chick glycogen body
Authors: Benzo Camillo A. , De Gennaro Louis D.
Published: June 2005

Glycogen synthetase and phosphorylase activities were quantitatively determined for the first time in glycogen body tissue from late embryonic and neonatal chicks. For comparative purposes, these enzyme activities were examined also in skeletal muscle and liver from pre‐ and post‐hatched chicks. The present data show that the forms of glycogen synthetase which exist in the chick glycogen body are similar to those found in both liver and muscle, while glycogen body phosphorylases more closely resemble those forms characteristic of skeletal muscle.
The effect of ergocornine on melanophores of Ambystoma tigrinum: Evidence for suppression of pituitary MSH release
Authors: Platt James E. , Norris David O.
Published: June 2005

Injection of ergocornine into larval tiger salamanders (Ambystoma tigrinum) placed on a black background prevented the increase in melanophore index observed in saline‐injected controls. Larvae pre‐adapted to a black background showed a significant drop in their melanophores indices which persisted for up to 11 days following a single injection of 25 μg ergocornine (2.5 μg/g body weight). Dark‐adapted, ergocornine‐treated larvae with melanin concentrated in the melanophores responded to a single injection of 20 μg mammalian ACTH with rapid and complete dispersion of melanin within the melanophores. The same larvae did not respond similarly to a single injection of 25 μg ovine prolactin. These results support the hypothesis that ergocornine blocked the secretion of pituitary MSH in Ambystoma tigrinum.
Crayfish CNS: Minimal degenerative‐regenerative changes after lesioning
Authors: Bittner George D. , Ballinger M. L. , Larimer J. L.
Published: June 2005

Removal of an abdominal ganglion or a segment of a connective of the ventral nerve cord in crayfish (Procambarus simulans) resulted in little regenerative outgrowth from cut ends of CNS axons and no replacement of ablated cell bodies, even after 9–12 months. A few small‐diameter interneurons, but no giant axons, showed physiological and/or morphological evidence for regeneration across the lesion site. No behavioral, physiological or morphological evidence for degeneration of severed axonal segments of any interneuron (except for a few damaged segments of the septate lateral giant axons) was seen 2–3 weeks after lesioning and survival of isolated segments of medial giant axons was associated with hypertrophy of their glial‐connective tissue sheaths. Very little morphological degeneration of severed CNS interneurons was seen even 9–12 months after lesioning, except for isolated distal stumps of medial giant axons.

Physiological evidence for degenerative changes was obtained after 9–12 months for CNS synapses posterior to the lesion site in that these synapses rapidly fatigued with repeated stimulation whereas synapses anteror to the lesion continued to function normally. This difference in synaptic efficacy might be explained by an interruption of a rostral‐caudal transport of axoplasmic proteins in these ventral nerve cords (Fernandez et al., '70, '71). A rostral‐caudal flow of trophic substances might also account for the 9–12 month survival of some anterior segments of lateral giant axons which were disconnected from their original cell bodies but which remained in contact with rostral cell bodies via septate junctions.
Origin of the dental lamina in the regenerating salamander jaw
Authors: Graver Heber T.
Published: June 2005

The origin of the dental lamina (DL) in the regenerating lower jaws of seven species of larval and adult urodeles was examined by various transverse amputation procedures.

Collectively the results indicate that jaw and DL regeneration following experimental amputation is a widespread phenomenon in urodeles. In 1/4 and 1/2 amputated jaws of larvae (DL present in the stump), the dental epithelium was replaced from both the anterior and posterior ends of the regenerate area, while in adults it was replaced from the posterior stump tissues only. In 1/4 and 1/2 jaw removals (no DL present in the stump), larval forms exhibited a posterior regrowth of the DL, while in adults DL accumulated at the edge of the regenerate area, resulting in 1/4 and 1/2 edentulous jaws. Removal of all DL in both stumps in larval and adult forms resulted in completely edentulous jaws.

The DL does not arise de novo during regeneration, nor is it a direct outgrowth of the DL in the stump. Serial sections made in various planes of the area of the regenerating tip of the DL indicated that DL formation in the regenerate is an epithelio‐mesenchymal interaction caused by the inductive influence of remnant DL in the stump on the adjacent regenerating oral epithelium, resulting in a chain of proliferating and invading cells developing serially and sequentially through time. The mechanism involved in the inductive event remains undetermined.
Fluid reabsorption in the crayfish kidney labyrinth
Authors: Peterson Darryl R. , Loizzi Robert F.
Published: June 2005

In the crayfish, eyestalk extirpation produced noticeable blood dilution within three to four hours when maintained in tap water. Microscopic examination of kidney labyrinth cells following this treatment revealed an increase in the width and number of intercellular spaces and a decreased cell volume. Conversely, exposure of the intact animal to 50% sea water for the same interval concentrated the blood, and intercellular spaces and cell volumes did not change. Finally, with both treatments together (i.e., eyestalk extirpation and immersion in 50% sea water), blood became concentrated, but intercellular spaces increased in width and cells shrunk, as occurred with eyestalk extirpation alone. Effects of these whole‐animal treatments on mitochondria, intracellular compartments and basal invaginations among labyrinth cells are also noted. The findings suggest two conclusions. First, it is proposed that the dilation of intercellular spaces is due to an efflux of fluid from the cells into the lateral compartments. Such movements may be part of a mechanism effecting isotonic transepithelial fluid flow from lumen to blood as demonstrated in other systems. Second, since eyestalk extirpation is known to induce hormonal conditions simulating ecdysis, and since the morphological changes in the labyrinth following extirpation occur whether the blood has become diluted or concentrated, it is suggested that solute reabsorption by the crayfish kidney is under direct hormonal control. Such a mechanism could be especially useful during molt‐induced water uptake to enhance reabsorption of solutes and prevent loss of fluid.
Electron microscopy of kinetochores in whole mount spreads of mitotic chromosomes from hela cells
Authors: Moses M. J. , Counce S. J.
Published: June 2005

Kinetochores are demonstrated for the first time in mitotic chromosomes that have been spread on a hypophase and selectively contrasted. The kinetochores have comparable characteristics to those seen in thin sections.
Human chondrogenesis: Glycosaminoglycan content of embryonic human cartilage
Authors: Lash James W. , Saxén Lauri , Kosher Robert A.
Published: June 2005

Transitions in glycosaminoglycan content occur during early cartilage development in 5–8 week human embryos. With increasing embryonic age, there is an increase in chondroitin 6‐sulfate relative to chondroitin 4‐sulfate, and a large decrease in heparan sulfate. Keratan sulfate is detectable after 8 weeks. Mesonephros and limb buds show distinct differences from all other tissues.
Deafferentation studies on motor activity in the chick. I. Activity pattern of hindlimbs
Authors: Narayanan C. H. , Malloy R. B.
Published: June 2005

Neural crest precursors of dorsal root ganglia at lumbosacral levels of the spinal cord of chick embryos were destroyed by superficial cauterization at very early stages (52–64 hours) in order to study the influence of afferent input from the periphery on activity patterns of the hindlimbs during embryonic, hatching and post‐hatching periods. Neither total nor local activity of the hindlimbs in deafferented chick embryos showed any significant difference quantitatively from those of control embryos between 9 and 17 days of incubation. These embryos exhibited typical prehatching and hatching behavior except the final climax stage of hatching in which the embryo normally cracks the shell around the air space and emerges. The experimental embryos were unable to hatch by themselves. In hatched chicks, legs were incapable of making alternate stepping movements. These observations, discussed in the light of other experimental evidences, suggest that afferent input from the periphery is probably involved in the patterning of coordinated activity of the legs in the chick.
The effect of nerve growth factor on hindlimb regeneration in Xenopus laevis froglets
Authors: Robinson Helen , Allenby Kent
Published: June 2005

The effect of nerve growth factor (NGF) on hindlimb regeneration in postmetamorphic Xenopus laevis froglets was investigated. Two different dosage levels of NGF were tested on froglets whose hindlimbs had been amputated either above or below the knee joint. The course of regeneration in the NGF‐treated froglets was followed for 100 days post‐amputation.

Treatment with NGF at a level of 2,500 Biological Units per froglet increases the extent of hindlimb regeneration attained compared with the controls, regardless of the level of amputation. On the other hand, a higher dose of NGF, 5,000 Units per froglet, does not alter the extent of hindlimb regeneration significantly. Treatment with NGF at either dosage does not appear to affect the shape or histological constitution of the regenerated limb segment. The general shape of the regenerate correlates with the level at which the limb was amputated. All regenerates obtained in this study conform to a common pattern in terms of histological constitution. They are composed of a central core of cartilage with a perichondrial membrane surrounded by a thin layer of connective tissue and covered by fully differentiated epidermis. No differentiated bone, muscle or nervous tissue was detected in any of the regenerates, but evidence of cartilage calcification was observed in limbs amputated below the knee. Possible implications of these results are discussed.
Independence of ovarian masculinization and hypothyroidism in frog tadpoles after methimazole treatment
Authors: Hsü Chin‐yün , Huang Hsü‐Cheng , Chang Chieng‐Hsün , Liang Hsü‐Mu
Published: June 2005

This work aims to clarify whether methimazole‐induced sex transformation in tadpole ovaries is due to the goitrogenic property of the drug as some authors have suggested. Intact, thyroidectomized, and hypophysectomized female tadpoles of Rana catesbeiana were reared in 0.005% methimazole solution as experimentals; three parallel groups in tap water served as controls. After four months of goitrogen treatment, all six groups of tadpoles were sacrificed and their gonads sexed histologically. The results showed that intact, thyroidectomized, and hypophysectomized tadpoles in tap water had normal ovaries, while ovaries of intact, thyroidectomized, and hypophysectomized animals in methimazole solution were all transformed at least partially, and in some cases, almost completely to testes. Histologically, the process of sex transformation resulting from methimazole treatment was not different from that observed in heat‐treated tadpoles or in spontaneous sex reversals. These findings demonstrate that the hypophysis and thyroid were not involved in goitrogen‐induced sex transformation. This provides additional evidence in support of our belief that various factors, such as heat, sex hormones, gene action, and goitrogens though diametrically different per se, all deliver a direct and detrimental effect on the ovary, triggering a common pathway from destruction of oocytes to induction of rete cells which results ultimately in sex transformation.
Galapagos iguanas: Amblyrhynchus and Conolophus serum protein relationships
Authors: Higgins Paul J. , Rand Charles S. , Haynes Janet‐L.
Published: June 2005

The serum proteins of two genera of Galapagos iguanas were studied by means of immunochemical and electrophoretic methods. The albumin‐like fraction of the serum of the Galapagos land iguana, genus Conolophus, demonstrated greater anodal mobility than the albumin of Amblyrhynchus, the Galapagos marine iguana. The marine reptile was shown to possess four antigenic serum components not found in the land reptile. Double‐diffusion analysis, using rabbit antiserum to the serum of Amblyrhynchus cristatus (Santa Cruz Island), indicated taht the antigenic profile of the Santa Cruz, Hood, Tower, Albemarle and James Island populations of Amblyrhynchus were identical when the eliciting immunogen is the serum of the Santa Cruz marine iguana.
Physiological studies of conducting systems in the colonial hydroid Hydractinia echinata. I. Polyp specialization
Authors: Stokes Darrell R.
Published: June 2005

Electrical activity generated by electrical stimuli has been recorded through suction electrodes placed on gastrozooid and dactylozooid polyps of the colonial hydroid, Hydractinia echinata Flemming. The polymorphism so characteristic of a Hydractinia colony extends to the physiological machinery controlling the behavior of the different polyp types. Contraction of gastrozooid polyps, where the muscle elements are uniformly distributed within the epidermis, is correlated to an electrical event termed the symmetrical contraction potential (SCP). The SCP is conducted about 4.4 cm/sec. Two kinds of electrical activity are correlated to distinct behavioral events of the specialized asymmetrically coiled dactylozooid polyps: (1) Dactylozooid coiling potentials (DCPs) are conducted at about 4.6 cm/sec and are correlated with contraction of a thin band of muscles on the concave side resulting in asymmetrical contraction and a marked coiling of the polyp. (2) Dactylozooid lashing potentials (DLPs) are conducted at about 9.1 cm/sec and have a threshold 50 per cent or more higher than DCPs. DLPs are correlated with contraction of well‐developed muscles on the convex side resulting in a rapid uncoiling or “lashing” of the dactylozooid polyp. Dactylozooid coiling is correlated to an incremental spread of conduction within the colony whereas lashing occurs during colony‐wide through‐conducted excitation. Very small electrical spikes (50–200 μV amplitude) have been recorded from both gastrozooids and dactylozooids. These tiny potentials (TPs) are conducted at 15–21 cm/sec, have a threshold below that of the DCPs and SCPs, and are of unknown behavioral significance. On the basis of the characteristics of the electrical events, the differences in threshold, conduction velocity, and related spread of excitation, it is proposed that these three potentials represent activity within separate conducting systems — an incrementing conducting system (ICS), a through conducting system (TS), and a tiny potential system (TPS). Physiological and microscopical evidence suggest a nerve net origin for the ICS, and epithelial conduction for the TS.
In vitro maturation of mouse oocytes isolated from late, middle, and pre‐antral graafian follicles
Authors: Erickson Gregory F. , Sorensen Ralph A.
Published: June 2005

Oocytes were dissected from late, middle, and pre‐antral Graafian follicles from sexually mature mice (6–8 weeks old), cultured in vitro in a chemically defined medium for 18 hours, and scored for meiotic maturation. Between 83–91% of the oocytes removed from antral follicles (300–600 μm in diameter) progressed to either metaphase I or metaphase II. In marked contrast, 98% of the oocytes removed from pre‐antral follicles (100–150 μm in diameter) failed to resume meiosis and remained in the germinal vesicle stage. These and other data suggest there is a close correlation between the capacity of the mouse oocyte to resume meiosis and the appearance of the antrum in the developing follicle.
Blood glucose regulation in larval and adult salamanders (Ambystoma tigrinum)
Authors: Bartell Marvin Henry , Frye B. E.
Published: June 2005

Blood glucose in Ambystoma tigrinum is regulated at a lower level in larval (18.4 ± 0.7 mg%) than in adult (27.8 ± 0.8 mg%) animals. The difference is observed at all seasons, and is not related to differences in size, diet or sexual maturity. A difference in the blood glucose regulating mechanism in pre‐ and post‐metamorphic animals is further shown by three other observations: (1) larvae are more insulin sensitive than adults; (2) larvae have a slightly greater glucose tolerance than adults; and (3) pancreatectomy causes a more severe hyperglycemia in adults than in larvae.

The best hypothesis to account for all of these observations is that an increase in the amount and/or activity of insulin antagonistic hormones occurs at metamorphosis.
Collagen synthesis in the regenerating forelimb of the adult newt, Diemictylus viridescens
Authors: Johnson Martha C. , Schmidt Anthony J.
Published: June 2005

The regenerating and stump tissues of amputated forelimbs of the adult newt, Diemictylus viridescens, were analyzed for collagen content and synthesis. Collagen soluble and insoluble in 0.45 M NaCl was assayed by (1) spectrophotometric determination of hydroxyproline, (2) radiotracer determination of 14C‐proline incorporation, and (3) radiochromatographic analysis of the 14C‐proline/14C‐hydroxyproline ratio in the two collagen fractions.

The results obtained reveal that there is significantly less saline insoluble as well as soluble collagen in the regenerating limb tissues than in the basal stump of the amputee, though a soluble fraction is demonstrable throughout the course of regeneration. By ninety days after amputation, there is a significant increase in the insoluble collagen fraction in the regenerating limb.

The soluble collagen fractions assayed in the regenerating tissues are newly synthesized protein, and this synthetic activity appears to be greatest during the paddle and early digitiform stages of regeneration. The soluble collagen extracted from regenerates appears to be less completely hydroxylated with respect to hydroxyproline content than obtains in corresponding fractions from limb stump and control limb tissues.
Cell division and determination of the dorsal lip in Rana pipiens embryos
Authors: Grant Philip , Youngdahl Pamela
Published: June 2005

UV irradiation of vegetal halves of fertilized eggs of Rana pipiens delays the onset of gastrulation and inhibits neural induction. To test a hypothesis that delay in dorsal lip formation results from inhibition of mitotic activity in vegetal halves we examined the incorporation of thymidine H3 into DNA of whole and half irradiated embryos. Tritium labeled thymidine was injected into control and irradiated eggs and at six hour intervals samples were taken until controls had reached mid gastrula stages. Whole embryos as well as animal and vegetal halves were compared for levels of incorporation into DNA. No significant differences were seen between control and irradiated whole or animal half embryos but irradiated vegetal halves displayed a 15–20% reduction in incorporation into DNA at 18 and 24 hours. This result is consistent with (but by no means proves) the hypothesis that UV inducedgastrulation delay results from inhibition of cell division of vegetal half cells.
Localization of rhodomelanochrome in melanosomes of leaf frogs
Authors: Bagnara Joseph T. , Ferris Wayne
Published: June 2005

Rhodomelanochrome, a new pigment extracted from the skin of leaf frogs is localized in the fibrous portion of the large melanosome typical of these frogs. Skin extracted with NaOH contains melanosomes possessing a diminished fibrous component and melanophores in thin sections of skin treated with NaOH are filled with melanosomes that lack large areas of the fibrous zone. The appearance of the electron‐dense core of the melanosome of untreated skin is unchanged and it is suggested that the leaf frog melanosome is composed of an inner kernel of eumelanin and an outer fibrous component of rhodomelanochrome.
Massive cytoplasmic transfers between early blastomeres of Rana pipiens eggs
Authors: Ansevin Krystyna D. , Williams Barbara J.
Published: June 2005

A technique for injecting large amounts of cytoplasm into early blastomeres of frog eggs is reported. It has been possible to replace part of the cytoplasm of animal blastomeres at the 8‐cell stage with injected cytoplasm, some of which was also included in the upper region of the corresponding cell in the vegetal hemisphere. When the injected cytoplasm matched the stage and type of the cytoplasm at the site of injection, the majority of the recipient embryos developed into normal larvae. If it matched the stage, but not the type, the majority of the eggs developed abnormally. The experiments also indicated a relationship between the stage of injected cytoplasm (4‐64+ cells) and the frequency and severity of abnormalities.
Cell surface structure of rodent sperm heads
Authors: Phillips David M.
Published: June 2005

Replicas of critical point dried rodent sperm were examined by transmission electron microscopy. The surface of rat sperm heads appeared to be coated with regularly spaced 90A lamellar material. The plasma membrane overlying the acrosomal region of guinea pig spermatozoa displayed a regular scalloped array of lamellar structures. In replicas, the surface of Chinese hamster spermatozoa appeared coated by an array of small tubules and vesicles in the region overlying the acrosome. It was possible to obtain replicas of the outer acrosomal membrane by removing the plasma membrane of mouse spermatozoa by brief treatment with Hank's balanced salt solution containing 0.2–0.5% MgCl2. Replicas of the surface of the outer acrosomal membrane reveal evenly spaced, hexagonally‐packed 90A particles similar to those which have been observed by other workers in replicas of freeze fractured outer acrosomal membranes. The finding of hexagonally arranged structures on the surface of the outer acrosomal membrane which appear very similar to those which have been observed in the plane of the membrane suggests that protein molecules in the plane of the membrane may protrude through or in some other manner distort the membrane surface. The post‐acrosomal region of mouse sperm displays parallel lamellae with 100A spacing. If surface changes occur on sperm heads during maturation or capacitation, it should be possible to detect them with this technique.
An effect of accumulated matrix on sulfation among cells in a cartilage colony: An autoradiographic study
Authors: Solursh Michael , Karp Gerald C.
Published: June 2005

In this report an autoradiographic approach is used to compare synthetic activities of cells within differentiated cartilage colonies. While amino acid incorporation is uniform throughout the colony, H3‐uridine is incorporated more actively by cells having little matrix, cells which are typically in the peripheral regions of a colony. On the other hand S35O4 is incorporated most actively by cells in the colony centers. This difference in sulfation appears to occur independently of the mitotic state of the cells, since it is apparent in both growing and near‐stationary cultures. Instead, there is a correlation between the accumulation of extracellular matrix and more active levels of sulfation. In support of the idea that matrix creates a microenvironment more favorable to chondrogenesis is the observation that a brief treatment with hyaluronidase, which removes about 60% of the S35O4 from prelabeled cultures, depresses sulfation, as determined both autoradiographically and biochemically by the isolation of labeled glycosaminoglycans. The possible role of extracellular matrices in altering the expression of differentiated functions by creating a more favorable microenvironment is considered.
Exogenous and endogenous control of the annual reproductive cycle in the male golden hamster: Participation of the pineal gland
Authors: Reiter Russel J.
Published: June 2005

Testes and accessory sex organs (seminal vesicles and coagulating glands) of hamsters exposed to natural lighting (NL) conditions beginning September 22 underwent complete degeneration by October 31. The following February the testes began to regrow with the regeneration being complete by mid to late March. Associated with the atrophic response of the testes during the winter months was a consistent depression in pituitary prolactin and an inconsistent decrease in pituitary luteinizing hormone levels. If hamsters are pinealectomized prior to their exposure to NL, the sexual organs do not atrophy and the pituitary hormone levels do not drop. Moving hamsters from NL to the long daily photoperiods (light:dark cycles of 14 hrs light and 10 hrs darkness— LD 14:10) of the laboratory near mid winter is followed by regrowth of the gonads and accessory glands. Regeneration of the reproductive system in the spring is not a function of increasing photoperiodic length since if animals are completely deprived of light (by blinding) in February, the gonads still regenerate. When hamsters are exposed to LD 14:10 cycles during the subsequent summer, the return to NL on September 22 is followed by a second involution of the reproductive system. However, if the period of LD 14:10 (the simulated summer) is shortened by ten weeks, the second return to NL does not initiate involution of the reproductive system. During the simulated summer complete light deprivation by blinding is incapable of forcing atrophy of the sexual organs.
Localization of prostaglandin on the plasmalemma of rabbit sperm
Authors: Bartoszewicz Wladyslaw , Dandekar Pramila , Glass Robert H. , Gordon Mildred
Published: June 2005

Prostaglandin and prostaglandin receptors were localized on unwashed ejaculate rabbit sperm utilizing ferritin conjugated antibody to prostaglandin. Reaction was obtained over the acrosomal portion of the plasma membrane, with a greater aggregation over the apex of the head. The remainder of the head plasmalemma and flagellum showed no deposits of reaction product. The reaction did not occur if the sperm were washed prior to incubation with the labelled antisera. However enhanced binding of ferritin was demonstrated if washed sperm were pre‐incubated in PGE1.

No reaction was seen in similar studies with human sperm.
Neurosecretory stimulation of galactogen synthesis within the Helix pomatia albumen gland during organ culture
Authors: Goudsmit Esther M.
Published: June 2005

The albumen gland portion of the female reproductive tract in pulmonate gastropods produces two metabolically allied polysaccharides, galactogen and glycogen. Galactogen accumulates in preparation for summer egg‐laying, glycogen in preparation for winter hibernation. Synthesis of each polysaccharide may be under neurohormonal control, therefore an organ culture bioassay for such neurosecretory influences was devised.

This publication reports: (1) the composition of a chemically defined medium which will sustain both the albumen gland and brain of Helix pomatia in organ culture; (2) a method for the separation of galactogen from glycogen in aqueous solution: glycogen is co‐precipitated with concanavalin‐A while galactogen remains in solution; and (3) activation of galactogen synthesis within albumen gland explants of a hibernating Helix, when this gland is cultured in the presence of a brain taken from a reproductively active snail.
The differential effects of prenatal and postnatal audiogenic stress on fluctuating dental asymmetry
Authors: Siegel Michael I. , Doyle William J.
Published: June 2005

Audiogenic stress has been shown to have an effect on the development of molar teeth. The present study demonstrates the relative contribution of prenatal and postnatal stress components to increases in fluctuating dental asymmetry in the laboratory rat. It is shown that there is a limit to the amount of change which can be environmentally induced and that if this limit is reached with prenatal stress, postnatal stress will have no significant effect. Audiogenic stress is shown to effect differentially mandibular and maxillary first molars. Length is stable for the maxillary dentition and width is stable in the mandibular molars.
The role of a normal lens in Wolffian lens regeneration
Authors: Williams Leah A. , Higginbotham Linda T.
Published: June 2005

The mid‐ventral third of the iris was excised from 61 adult Notophthalmus viridescens hosts, and the mid‐dorsal third of the iris from donor eyes was implanted in its place. After the iris healed and the host lens was removed, two lens regenerates developed, one from the host and one from the transplanted iris. The host regenerate was removed 53–91 days after the first lentectomy. Animals were sacrificed 1–40 days after the second lentectomy. A lens developed from the host dorsal iris in the presence of a normal regenerated lens in 75% of the cases. A large space was present between the transplant derived lens and host iris for approximately 20 days after the removal of the host lens at lentectomy 2. Stimulatory factor(s) from the neural retina could reach the competent iris through this space, inducing it to regenerate a lens. Therefore, contact between the normal lens and iris probably acts to prevent lens regeneration.

In other experiments, variable amounts of neural retina from either adult or larval donors were implanted into the anterior chamber of adult newt eyes in which the lens, iris and neural retina remained in their normal relationships. Implants also contained dorsal iris, ventral iris, or no iris at all. Competent iris tissue, stimulated by the implanted retina, showed only early stages of lens regeneration, but larval retina effected a greater response than adult retina. This limited response may result from the small amount of retina in the implant, a deficiency in retinal stimulus, or a competition for the retinal factor(s) by competent iris tissues.
The effects of castration on song development in zebra finches (Poephila guttata)
Authors: Arnold Arthur P.
Published: June 2005

It has been suggested that the learning processes which occur during the critical period for bird song development are dependent on androgens. Castration of male zebra finches (Poephila guttata, Estrildidae) at ages 9–17 days did not prevent song development, and normal learning occurred after the time of castration. Thus the learning processes of song development occur in the absence of gonadal androgens. Castrates tended to develop song more slowly than normals, which is potentially attributable to a decreased rate of singing in the castrates, or to a direct effect of androgen on the learning processes.
The quantitative role of hemocyanin in aerobic respiration of limulus polyphemus
Authors: Mangum C. P. , Freadman M. A. , Johansen K.
Published: June 2005

Measurements of the total oxygen content of post‐ and prebranchial blood in Limulus polyphemus indicate that hemocyanin transports less than half of the oxygen consumed in water but almost 90% in air. Half of the increase in hemocyanin function during air exposure is due to the occurrence of a reverse Bohr effect.
Immunological immobilization of detached rabbit sperm tails
Authors: Metz Charles B. , O'rand Michael G.
Published: June 2005

Motile rabbit sperm tails that lack heads are immobilized by antibody plus complement. Accordingly, immunological immobilization may not necessarily require the extensive sperm acrosomal damage previously reported in immobilized normal sperm.
The effects of castration and androgen replacement on song, courtship, and aggression in zebra finches (Poephila guttata)
Authors: Arnold Arthur P.
Published: June 2005

Castration of adult male zebra finches (Poephila guttata, Estrildidae) reduces their singing rate and the tempo of song, but castrates continue to sing song identical in form to preoperative song. Injection or implantation of testosterone propionate (TP) but not of vehicle alone reverses the changes produced by castration. Castration or partial castration also reduces the frequency of courtship, copulation, and aggression. Androgen (TP) replacement reverses these changes, but control injections do not. The persistence of song after castration contrasts with the abolition of song by castration in other birds, and this may be related to the natural history of zebra finches.
Panting thresholds of lizards. IV. The effect of dehydration on the panting threshold of Amphibolurus barbatus and Amphibolurus muricatus
Authors: Parmenter C. J. , Heatwole Harold
Published: June 2005

Amphibolurus barbatus which occupies arid and mesic habitats elevates its panting threshold with increasing loss of body water, thereby minimizing water loss at the expense of thermoregulatory effectiveness. Change in panting threshold is greatest up to losses of body water of 6–8% of hydrated weight, after which adjustment of the threshold is of lesser magnitude. Amphibolurus muricatus, a species restricted to the more mesic regions of Australia, does not show any change of panting threshold with progressive dehydration.
The immune response of the teleost, Tilapia mossambica to soluble and cellular antigens
Authors: Sailendri K. , Muthukkaruppan Vr.
Published: June 2005

The immune response of Tilapia mossambica to bovine serum albumin (BSA) and sheep red blood cells (SRBC) was characterized in detail in terms of the appearance of hemolysin plaque‐forming cells and circulating antibodies at 30°C.

Plaque‐forming cells (PFC) were detected in the spleen, head‐kidney and thymus of immunized fish and the maximum number was observed in these organs on the fifth day after immunization with SRBC. Peak circulating antibody response occurred on day 8 for SRBC and on day 11 for BSA. Following the second injection of the same antigen, a specific anamnestic response was observed with increased production of PFC and serum antibody.

No cross reactivity was found when anti‐SRBC antibody was tested with rat erythrocytes. Tests with 2‐mercaptoethanol showed that all of the agglutinating antibody produced after both the first and second injection was mercaptoethanol sensitive.

Analysis of histological and smear preparations revealed that there were consistent cellular changes occurring in the spleen as well as the head‐kidney due to immunization.
Electron microscopic study of erythrocytes in developing rainbow trout, Salmo gairdnerii irideus, with particular reference to changes in the cell line
Authors: Yamamoto Masamichi , Iuchi Ichiro
Published: June 2005

The fine structure of the first erythroid cells in the embryonic circulation of the rainbow trout and new erythroid cells appearing after hatching was examined by scanning and transmission electron microscopy. The first erythroid cells in the embryos. where circulation has just begun, are very immature in ultrastructural characteristics; they are spherical, relatively large, and contain a large nucleus with diffuse chromatin and numerous free ribosomes mostly occurring as polyribosomes. The cells divide in the circulatory system. As development proceeds, the entire population undergoes a synchronous maturation, i.e., transformation into round and flat discs, progressive heterochromatization, reduction in number of cytoplasmic organelles, especially of ribosomes, and a concomitant increase of hemoglobin content. The fully mature first erythroid cells persist until after hatching and are gradually replaced by a new population of erythroid cells which begin to appear in the circulatory system within a few days after hatching. The new cells are at first small and spherical, and show immature ultrastructural features, but no dividing cells were encountered. The cytological changes accompanying maturation are almost parallel to those seen in the first class of erythroid cells. In the circulatory system of fry, where yolk absorption has just been completed, almost all the erythroid cells are mature. These cells are uniformly flat and elliptical discs. The differences in ribosome numbers in electron micrographs of erythroid cells from different stages of development are also consistent with the existence of two series of erythroid cell maturation in the peripheral blood of the developing rainbow trout.
Morphogenetic gradients in multiple‐graft Hydra viridis. I. The effects of colcemid and colchicine
Authors: Shostak Stanley , Adams James A.
Published: June 2005

The morphogenesis of so‐called secondary (2°) heads, budding regions and feet, and separations at graft borders is studied in multiple‐graft animals containing three gastric regions (3g animals) treated with Colcemid or colchicine. Control animals consist of three non‐treated pieces. Animals consisting of two non‐treated and one treated piece are also employed. The main effects of Colcemid are the promotion of graft healing at the distal graft border, and of 2° head formation on the proximal gastric region (g‐1). Colchicine also promotes graft healing at the distal graft border, but in contrast to the effect of Colcemid, promotes the formation of ectopic feet (tertiary feet) and inhibits head regeneration at the distal end of the middle gastric region (g‐2). Colchicine also accelerates an inversion of polarity in 2° budding regions on the g‐2 pieces of animals with 2° heads on their g‐1 pieces. Treatment of a distal graft piece with Colcemid promotes 2° head formation on the nearest proximal piece which is not treated, but the inhibition of 2° head formation by colchicine occurs only on colchicine treated pieces. The morphogenetic effects of the drugs are interpreted as consequences of their actions on nerve differentiation and cell division. The paper argues that homeostatic control of a hydra's cell population depends on dividing cells influencing cell loss, and that similar mechanisms are involved in the rejection of a graft and the separation of a bud.
Parthenogenic development after chemical treatment of Xenopus laevis spermatozoa
Authors: Jones Pamela , Jackson H. , Whiting M. H. S.
Published: June 2005

Eggs of Xenopus laevis were fertilized in vitro by spermatozoa pre‐treated with various concentrations of aziridinyl urea (ethyleneurea) for between 30 and 120 minutes. At 2 and 4 mg/ml for 30 minutes there was a high incidence of abnormal embryos, few of which developed into tadpoles; after 6 and 8 mg/ml no tadpoles were produced. However, the highest concentration, 10 mg/ml, yielded 66% of tadpoles, only 7% of which were obviously abnormal. With increasing time the same pattern of events was obtained except for a displacement towards the lower concentration ranges. Tadpoles developing from these latter experiments were found to be haploid. The results resemble those obtained by exposure of Rana pipiens spermatozoa to X‐rays and ultraviolet light, with the production of gynogenetic embryos, usually referred to as the Hertwig effect.
Tissue interaction: Morphogenesis of the lateral‐line system and labyrinth of vertebrates
Authors: Merrilees M. J.
Published: June 2005

A cord of specialized epithelial cells is present in the canals of the lateral‐line system and membranous labyrinth. Transplant experiments suggest that these cells control the deposition pattern of surrounding connective tissues such as scale, cartilage and bone, and thus play a significant role in control and maintenance of canal morphology.
Relationship between two kinds of hatching enzymes in the hatching liquid of the medaka, Oryzias latipes
Authors: Yamagami Kenjiro
Published: June 2005

The relationship between the hatching enzymes I and II of the medaka, Oryzias latipes, was studied by examining their behavior on gel filtration column chromatography and their responsiveness to added reagents including certain inhibitors. Enzyme I, of higher molecular weight, could be converted to the lower molecular weight enzyme II during purification. The results support the conclusion that enzyme I is a complex form of enzyme II combined with another substance.
Mouse embryo development in vitro: Effects of inhibitors of RNA and protein synthesis on blastocyst and post‐blastocyst embryos
Authors: Rowinski Jan , Solter Davor , Koprowski Hilary
Published: June 2005

The effect of inhibitors of RNA synthesis (Cordycepin, Actinomycin D) and protein synthesis (Cycloheximide) on the development and growth of mouse blastocysts in vitro was explored. Blastocysts exposed in vitro for 24 hours to 50 μg/ml Cordycepin, 0.005 μg/ml Actinomycin D, or 0.1 μg/ml Cycloheximide grew and began to attach to the dish in the similar manner as did the controls. Cell number, 3H‐thymidine‐labeling index and mitotic index in treated blastocysts were also similar to controls. Control blastocysts grown in vitro for six days attached to the dish, trophoblastic layer was spread and inner cell mass continued to grow and formed an egg‐cylinder like structure. Blastocysts grown in constant presence of 50 μg/ml of Cordycepin in the medium or those exposed to inhibitor only for the first 24 hours failed to develop inner cell mass derivatives in culture, although the growth of trophoblastic cells was as in controls. The same results were obtained if blastocysts were exposed to 0.005 μg/ml of Actinomycin D or to 0.1 μg/ml of Cycloheximide either continuously or for the first 24 hours. Higher concentrations of Actinomycin D (0.05 μg/ml) or Cycloheximide (1 μg/ml) were toxic for the blastocysts causing their degeneration within 24–48 hours. Our results suggested that appropriate concentrations of RNA or protein synthesis inhibitors could prevent the development of inner cell mass derivatives with essentially no effect on the development of primary trophoblast. This would indicate that the process of differentiation of inner cell mass cells is much more sensitive to metabolic inhibitors than the differentiation of giant trophoblastic cells.
Effect of prolactin on sugar and amino acid transport by the rat jejunum
Authors: Mainoya James R.
Published: June 2005

After two daily ovine prolactin injections in rats, significant increases in jejunal absorption of glucose, glycine and proline, as well as of fluid and NaCl, occurred. Although ouabain caused dramatic reductions in fluid, sodium, chloride and glucose transport, prolactin had an effect even in the presence of ouabain. Mucosal hyperosmolality significantly decreased fluid, sodium and chloride absorption but had no significant effect on glucose transport. Addition of prolactin in vitro had no effect on intestinal absorption. Prolactin‐induced increases in transport of fluid, NaCl and organic nutrients by the mammalian jejunum may play an important role in nutritional and osmoregulatory adaptations.
Osmoregulation in the fresh water sponge, Spongilla lacustris
Authors: Brauer Elizabeth B.
Published: June 2005

External medium passed through the canal system of small Spongilla lacustris at the rate of 70 body volumes per hour, allowing for little or no modification of its composition by the animal. Consequently any osmotic gradient between medium and animal was experienced at the cell level. Forty or more contractile vacuoles arranged around the nucleus in each basal pinacocyte removed fluid at the rate of 24.7 ± 1.0 μm3/cell/min in 1.3 milliosmolal (mosm) medium. Output of the contractile vacuoles depended in a nearly linear fashion on the osmotic concentration of the medium, decreasing to zero at 12–16 mosm. The contractile vacuoles responded to the osmotic concentration of the medium, not to ionic strength or the concentration ratios of particular ions. Osmotic concentration of the vacuolar fluid can be estimated as 10–40 mosm, leading to the hypothesis that contractile vacuoles of sponges function by isotonic water separation.
Form and pattern in ciliated protozoa: Analysis of a genic mutant with altered cell shape in Tetrahymena pyriformis, syngen 1
Authors: Doerder F. P. , Frankel J. , Jenkins L. M. , Debault L. E.
Published: June 2005

A single cell isolated from the sexual progeny of mutagenized parents gave rise to a clone of cells with an abnormal, conical shape. Breeding analysis revealed that this shape results from the action of a single recessive gene, co (conical). Homozygous mutant cells are shorter and wider than wild type cells, and have their widest point at a more posterior position. Nonetheless, cortical parameters such as number of ciliary rows, number of ciliary units within these rows, and positions of contractile vacuole pores remain essentially unchanged in conical cells, suggesting a considerable degree of mutual independence of pattern and form.

Shape changes prior to cell division bring about some convergence in form of dividing conical and wild type cells. However, in conical cells the new oral apparatus and fission line form well posterior to the cell equator, so the opisthes are invariably smaller than proters. Macronuclei nonetheless undergo constriction at the normal central location, and the characteristic inequality in the DNA content of the two macronuclear division products is not increased by the conical condition.

Generation times are, on the average, nearly the same in the two wild type daughter cells and in conical proters, while the small conical opisthes have generation times averaging one‐third longer. This prolongation explains why population doubling times are always somewhat longer in cultures of conical cells than in parallel cultures of wild type cells. The unusually long generation times of conical opisthes allows for the compensation of initial size differences.

Observations on shape changes in conjugating cells of various genotypic combinations suggest that the wild type gene product is not freely exchangeable across the conjugation bridge.

The implications of the conical phenotype for problems of cellular patterning and positioning of organelle systems are considered in the DISCUSSION.
Microfibrillar structures in the nucleus and cytoplasm of amoeba proteus (1)
Authors: Leeson T. S. , Bhatnagar R.
Published: June 2005

The presence of microfibrillar structures in the nucleus and cytoplasm of Amoeba proteus has been described after glutaraldehyde and osmium fixation. The possible roles of cytoplasmic microfibrils in the contraction process of amoeba and nuclear microfibrils in the formation of the honeycomb nuclear lamina are discussed.