bluuebunny/crossref_metadata_2025_split huggingface dataset:
Nervous system transplantation in hydra
Authors: Saffitz Jeffrey E. , Burnett Allison L. , Lesh Georgia E. 
Published: June 2005

AbstractCnidarians are the most primitive metazoans possessing a nervous system. The hydroid nervous system consists of single sensory, neurosecretory and ganglionic cells concentrated at the extremities of the animal. Present evidence suggests that nerve tissue arises from the differentiation of interstitial cells.Exposure of hydra to nitrogen mustard (methyl bis (beta‐chloro ethyl) amine hydrochloride) causes the selective elimination of interstitial cells (Diehl and Burnett, '64). Cells which normally arise from interstitial cell differentiation subsequently become depleted. Distoproximal grafts between normal hydra and nitrogen mustard treated animals of a different species result in interstitial cell migration across the graft junction. Autoradiographic evidence demonstrates that the host hydra accepts the donor's interstitial cells which proliferate and differentiate into nerve tissue and functional cnidocytes.Although newly established cnidocyte populations are normal in seven day old grafts, nerve and interstitial cell populations are reduced. Furthermore, there is an abnormal apico‐basal distribution of interstitial cells in these grafts.A comparison of “nervous system transplant” animals with those treated with nitrogen mustard for a similar time period but not grafted suggests that the transplanted nervous system is functional. The ultimate death of experimental animals supports speculation that nitrogen mustard causes irrevocable gastrodermal damage.Various parameters germane to the function of the nervous system in hydra are being established, including developmental, behavioral and electrophysiological correlates. Once nervous system transplant chimeras are reared in sufficient numbers, a comparison of these with host and donor species should provide insight into the functional nature of hydra's nervous system.
Marsupial and monotreme lactate dehydrogenase isozymes: Phylogeny, ontogeny, and homology eutherian mammals
Authors: Holmes Roger S. , Cooper Desmond W. , Vandeberg John L. 
Published: June 2005

AbstractLactate dehydrogenase (LDH) isozymes have been examined from tissues of mammalian species representative of the five families of marsupials and of the monotremes. Immunochemical, molecular hybridization, and tissue distribution studies showed that three genes (A, B and C) are responsible for LDH synthesis giving rise to five major isozymes in most tissues (LDH's A4, A3B1, A2B2, A1B3, and B4) and an additional isozyme (LDH‐C4) which is present only in mature testes. The LDH phenotypes of 93 erythrocyte samples from 31 marsupial and 2 monotreme species were analysed. Although the isozymic composition varied markedly within the marsupial families Macropodidae and Phalangeridae, the Dasyuridae showed remarkable uniformity, containing only LDH‐A4. The two monotreme species analysed also exhibited this latter pheno‐type in their erythrocytes. Ontogenic studies of the LDH isozymes of pouch young from Macropus parryi (pretty‐face wallaby) showed changes similar to those reported for the developing mammalian fetus in utero. The immature pouch young exhibited similar tissue patterns of LDH isozymes which diverged during growth in the pouch thus reflecting differential genetic activity. A comparison of the relative maturity of the eutherian fetus with marsupial pouch young may be made. From these observations, it is concluded that a high degree of correlation exists among the properties of eutherian, marsupial, and monotreme LDH isozymes.
An enzymatic comparison of sea urchin egg ghosts prepared before and after fertilization
Authors: Barber Mary Lee , Foy James E. 
Published: June 2005

AbstractGhosts were prepared from sea urchin eggs, before and after fertilization. Eggs were treated with Mg++ to stabilize the surface. Cytoplasm was then released by osmotically lysing the cells and washing repeatedly at low ionic strength. Microscopically, the resultant ghosts appear to contain the extraneous surface coats, some cell cortex, and the plasma membrane, but relatively little cytoplasm. This appearance and the higher specific activities of Na+‐K+‐ATPase, Mg++‐ATPase, and acetylcholinesterase in ghosts than in whole egg homogenates, indicates the usefulness of ghost preparations as egg surfaces in enzyme comparison studies. The specific activities of five of the six enzymes measured are different when compared in ghosts prepared before and after fertilization. Glucose‐6‐phosphate‐dehydrogenase, acetylcholinesterase, and Na+‐K+‐ATPase activities are greater in fertilized than in unfertilized egg ghosts, whereas the Mg++‐ATPase and glucose‐6‐phosphatase activities are lower. The changes in enzyme specific activities following fertilization may be related to structural and functional changes which occur in the egg surface at that time.
Opercular regulation in the polychaete Hydroides dianthus (verrill, 1873) II Control of opercular regulation
Authors: Schochet Joy 
Published: June 2005

AbstractWhen the adult functional operculum of the serpulid polychaete Hydroides dianthus is amputated at any level below the secondary cup, the rudimentary operculum develops into a functional one. Concomitantly a new rudimentary operculum regenerates from the stump of the former functional operculum. This reversal of asymmetry is proportional to the degree of injury (e.g., amputation > crushing > ligation > puncture). Amputating the rudimentary operculum does not affect the functional one, but in some cases the regenerating rudimentary operculum may differentiate into a second functional operculum. When distal portions of both opercula are removed, reversal occurs, and if the two opercula are amputated simultaneously at the base, a functional operculum regenerates on the side opposite its original position. If, however, the branchial apparatus is amputated together with both the functional and rudimentary opercula, the latter tends to regenerate on the original side. Thus the opercular regulatory system distinguishes between degrees and types of injury to the functional operculum, and the branchiae may be involved in opercular relationships.If the animal is decerebrated or the supraoesophageal ganglion is bisected, the opercula are still able to reverse normally. No reversal occurs when the external opercular nerves are severed, but in about one‐third of the animals reversal occurred after section of the internal nerve. No direct nervous connection is involved in opercular communications, but the internal opercular nerve is implicated in stimulating reversal.
Cell division and ribonucleic acid synthesis during the initiation of limb regeneration in larval axolotls (Ambystoma mexicanum)
Authors: Kelly Daryl J. , Tassava Roy A. 
Published: June 2005

AbstractMitotic activity and RNA synthesis were examined in normal regenerating limbs and denervated non‐regenerating limbs of larval axolotls during the first six days after amputation. H3‐uridine incorporation into RNA was measured by autoradiography of deoxyribonuclease treated sections. Grain counts indicated a significant increase in RNA synthesis in both normal and denervated limbs through the six‐day time period but a greater increase was seen in normal limbs.The Mitotic Index increased significantly in normal limbs on the fifth day postamputation. In contrast, no increase in M.I. was observed in denervated limbs.
Ultrastructure of the mesoglea in strobilae of Chrysaora quinquecirrha (scyphozoa)
Authors: Bynum Mary A. , Black R. E. 
Published: June 2005

AbstractLarge numbers of mesogleal fibers are found in constricted regions of Chrysaora strobilae. The mesoglea in these regions appears to be branched. Many fibers are oriented normal to the surfaces of gastrodermal cells. The mesoglea of non‐constricting regions contains similar fibers, most of which are not so oriented. Fibers and fiber bundles in the constricting regions may serve as a barrier to vertical cell migration, so that formation of ephyrae can occur. The fibers may also serve to stabilize constrictions once they are formed. Microfilament bundles, oriented transversely to the oral‐aboral axis, are present in the gastrodermis of scyphistomae.
Electron microscopic studies of planarian regeneration. II. Changes in epidermis during regeneration
Authors: Morita Michio , Best Jay Boyd 
Published: June 2005

AbstractHistological changes in planarian epidermis, as well as the differentiation of new epidermal cells during the course of differentiation, were studied with the electron microscope.Immediately after decapitation, pre‐existing epidermal cells of the area surrounding would stretch out over the cut‐surface and cover it completely with a thin film within 16 hours. However, these epidermal cells in the film were replaced by newly differentiated cells during the period extending from the second to sixth day of regeneration. Thus, after injury, the initial compensational closure is formed on the cut‐surface by the pre‐existing epidermal film, but the epidermis which is finally regenerated is formed by complete colonization of pre‐existing epidermis by newly differentiated epidermal cells. New epidermal and rhabdite‐forming cells were found not only in epidermis but also in the interior and sub‐epidermal regions of the blastema and in the old tissue close to the wound surface. Our observations suggest that ectodermally oriented cells, such as epidermal and rhabdite‐forming cells, originate from neoblasts at the anterior of the old body, close to its interface with the regeneration blastema; such neoblasts differentiate into rhabdite‐forming, or epidermal, cells as they migrate from the old somatic stump through the regeneration blastema into its epidermal surface layer. The characteristic polarity of epidermal cells appears in newly differentiated ones when they locate in the epidermal surface.
Synthesis and inhibition of macronuclear DNA in regenerating Blepharisma
Authors: Gavurin Lillian , Hirshfield Henry I. 
Published: June 2005

AbstractThe macronuclear cycle in regenerating posterior fragments of albino Blepharisma intermedium consists of four sequential stages which result in the reversible condensation of the macronucleus, and which are similar to those in the pigmented strain. Tritiated deoxyuridine incorporation occurs predominantly during the first three hours of regeneration and then declines. Of the early hours, hour 2 exhibits a significant increase in the proportion of heavily‐labeled cells. A statistical comparison of whole organisms labeled through exposure to radioactive precursor for a one‐hour period with fragments labeled at each hour of regeneration reveals a significantly greater number of labeled fragments for each of hours 1 through 4. Asynchronous patterns of DNA replication are evident in the macronucleus of both regenerating and whole cells. Oval‐shaped pellicular rings, consisting of dense accumulations of silver halide grains are evident during hours 5 and 6 of regeneration.Continuous inhibition of DNA synthesis during regeneration produces effects which depend upon the specific inhibitor employed. 5‐Aminouracil (AU) effects an appreciable delay of regeneration, without lethal or abnormal consequences. AU, hydroxyurea (HU), 5 bromodcoxyuridine (BUdR) and 5‐fluorodeoxyuridine (FUdR) exhibit a marked inhibitory effect upon division when they are administered to two‐hour fragments. The first three hours of regeneration is the period of greatest susceptibility to inhibitor action with respect to post‐regeneration division. AU, BUdR and FUdR interfere with the sequence of macronuclear events when these inhibitors are administered during hours 2–4 of regeneration. Contracted macronuclei are present at 24 hours and are related to division delay. HU, FUdR and BUdR treatment, during the later hours of regeneration, results in macronuclear fragmentation, branching and abnormal massing, respectively. Cytoplasmic abnormalities result from fragment exposure to the inhibitors during hours 4–6, with BUdR producing the most pronounced effects.
Studies on differentiation of Müllerian ducts in the quail, Coturnix coturnix japonica. II. Effects of sex hormones on nucleic acid synthesis in isolated female ducts
Authors: Iwamura Yukio , Koshihara Hidetoshi , Noumura Tetsuo 
Published: June 2005

AbstractThe present investigations were carried out in an effort to determine the mechanisms underlying differentiation in the avian Müllerian duct, especially the asymmetrical differentiation of the female ducts.Using the isolated female ducts of Japanese quail, the incorporations of 3H‐uridine and 14C‐thymidine were determined in vitro at several embryonic stages. Incorporation of 3H‐uridine was altered with some synchronous fluctuation during the embryonic period in both the left and right ducts, while 14C‐thymidine incorporation first decreased rapidly and subsequently, only slightly, during the same period.By administering sex hormones in vitro nucleotide incorporation was affected to an appreciable extent characteristic of the duct at each stage. This hormonal susceptibility was also periodically altered during duct differentiation. The growing left duct continued to receive an apparent stimulation under the hormonal conditions, while the involuting right duct was sometimes inhibited under the same conditions.Such hormonal susceptibilities may explain the asymmetrical differentiation of the female left and right ducts during this embryonic period.
Protein synthesis by the accessory gland of male house cricket, Acheta domesticus
Authors: Kaulenas M. S. , Yenofsky R. L. , Potswald H. E. , Burns A. L. 
Published: June 2005

AbstractThe accessory gland in male Acheta domesticus consists of several hundred tubules of variable length. The secretory cells of the tubules, which are very richly endowed with rough endoplasmic reticulum, surround a central cavity filled with product proteins. The proteins produced by the gland have been characterized by SDS‐polyacrylamide gel electrophoresis and gradient centrifugation. They constitute a complex mixture with a wide range in molecular weights and charge properties. The mRNAs for the proteins appear to be of long half‐life.Extensive regional specialization exists in the gland with respect to the types of export proteins formed. For the total gland, the acquisition of the full range of protein synthetic capacity is triggered by the imaginal molt, while the differentiation and growth of the tubules can continue in the absence of the molt.
Phenogenetics of the eyeless‐Dominant mutant of Drosophila melanogaster. II. Involvement of the nervous system
Authors: Arking Robert , Putnam Richard L. , Schubiger Margrit 
Published: June 2005

AbstractThe eyeless‐Dominant (eyD) mutation is a fourth chromosome insertional translocation which affects the eyes, antennae, ocelli, and sexcombs when heterozygous but is a larval‐pupal lethal when homozygous. By use of a crowding technique, it was possible to separate eyD homozygotes and heterozygotes with 100% accuracy at an early stage of larval development. Under these conditions, the eyD homozygotes had a biphasic lethal period since 45% died as first or second instar larvae and 55% died as pupae. The eyD/eyD pupal lethal, isolated by this technique, was able to form all the adult structures with the exception of the eye‐antennal disc derivatives. The brain was present but abnormal. In testing the competence of the eyD/eyD larval eye discs by means of transplantation experiments, it has been demonstrated that the mutant discs develop non‐autonomously. Histological studies have revealed the existence of neurological defects in both eyD heterozygotes and homozygotes. The eyD/eyD lethal larvae lacked detectable optic formation centers and showed an extreme reduction in the number of cells present in the cortex of the brain. The eyD/eyD lethal pupae possessed partial formation centers and also had severe reduction in the number of cortical cells. The eyD heterozygotes possessed normal appearing formation centers but they did exhibit a moderate reduction in the number of their cortical cells as compared to wild‐type. These studies have shown that there is a direct correlation between the extent of neurological damage and the time of developmental arrest. It appears that the eyD mutation must adversely affect the neuroblasts at a very early stage of development. As a working hypothesis, it is suggested that the eyD mutation operates via the same basic mechanism of cell death in heterozygous and homozygous animals.
Comparative immunology of Galapagos iguana hemoglobins
Authors: Higgins Paul J. , Rand Charles S. 
Published: June 2005

AbstractThe antigenic properties of the major hemoglobin component of the Galapgaos iguanas were studied using second‐approximation qualitative and quantitative immunochemical techniques. Phylogenetic distances, relative to the Galapagos marine iguana. Amblyrhynchus cristatus, were established on the basis of immunological cross‐reactions.
Adrenocortical function: Corticosterone levels in female BALB/c and C3H mice under various conditions
Authors: Hawkins Edward F. , Young Patricia N. , Hawkins Andrea M. C. , Bern Howard A. 
Published: June 2005

AbstractA diurnal rhythmicity in plasma corticosterone levels was demonstrated in female BALB/cCrgl and C3H/Crgl mice, with and without mammary tumor virus. Removal of the adrenals followed by metopirone treatment reduced circulating corticoid to non‐detectable levels in C3H but not in BALB/c mice. Dexamethasone reduced but did not abolish corticosteroid secretion in both strains. Neonatal exposure to exogenous hormones failed to cause any obvious change in corticoid levels. Bilateral ovariectomy of these neonatally treated mice at 40 days of age resulted in a subsequent lowering of plasma corticoid levels when compared with intact animals.
The effects of acetylcholine, biogenic amines and other vasoactive agents on the cardiovascular functions of the eel, Anguilla japonica
Authors: Chan D. K. O. , Chow P. H. 
Published: June 2005

AbstractThe blood pressure in the cardinal vein, cardiac chambers and ventral and dorsal aortae have been recorded from conscious eels in water. At low doses, acetylcholine reduced the heart rate but increased the transbranchial differential blood pressure. The effects were abolished by atropine but not by tubocurarine. At doses in excess of 0.1 μg/kg, a secondary rise in arterial blood pressure was observed which could be abolished by bretylium, phentolamine or phenoxybenzamine.Catecholamines did not affect the heart rate although a transient bradycardia due to reflex inhibition could be observed with adrenaline and noradrenaline. Catecholamines increased the cardiac contractile force through an α‐adrenergic mechanism which was blocked by phentolamine but not by propranolol. The relative potency was noradrenaline > adrenaline≫isoprenaline. A β‐adrenergic receptor located in the branchial circulation led to vasodilation and decrease in transbranchial differential pressure. Both α‐(vasoconstriction) and β‐(vasodilation) adrenergic receptors were present in the systemic circulation.Dopamine, 5‐HT, GABA and bradykinin caused bradycardia abolishable by vagotomy or atropine treatment. Angiotensin II was hypertensive but did not affect the heart rate nor the transbranchial differential pressure. Tyramine caused release of endogenous catecholamines. With repeated doses, tachyphylaxis to the drug was observed. Histamine was without any obvious cardiovascular effects in the eel.
Effects of interactions with older males on behavior and reproductive development in first‐year male red‐winged blackbirds Agelaius phoeniceus
Authors: Wiley R. Haven , Hartnett Sue A. 
Published: June 2005

AbstractMale red‐winged blackbirds Agelaius phoeniceus in their first year normally do not establish territories or breed. To investigate the possibility that interactions with older males might inhibit reproductive development of young males, we compared the behavior of first‐year males in the presence and absence of older males. For three months during the first half of the breeding season, we studied mixed‐ and single‐age groups of three males in standardized outdoor aviaries: two groups of three first‐year males (FFF groups), two groups of one older and two first‐year males (AFF groups), and one group of three older males (AAA group). In all groups one male established clear dominance, invariably the older male in AFF groups. The dominant male in FFF groups displaced subordinates less frequently than did the dominant older male in AFF groups early in the season, but equally frequently later. In May the largest testis weights of males in FFF groups were significantly lower than those of dominant older males in AFF groups. First‐year males in the absence of direct interactions with older males can achieve levels of aggressive behavior comparable to those of a dominant older male in similar social environments but the seasonal development of their aggressive behavior occurs later and their testes in May are smaller than dominant adults'. This delay in the seasonal development of aggressive behavior in first‐year males, independent of the immediate social environment, suggests that the age‐dependent territoriality of males in this species is not strongly regulated by effects of older males on the development of younger males.
Differential gene expression in multilocus isozyme systems of the developing green sunfish
Authors: Champion Michael J. , Whitt Gregory S. 
Published: June 2005

AbstractThe patterns of expression of eight multilocus isozyme systems were investigated in the differentiated adult tissues and the early embryonic stages (0‐210 hours after fertilization) of the green sunfish, Lepomis cyanellus. Enzymes encoded by approximately 23 gene loci were resolved by starch‐gel electrophoresis and detected by specific histochemical staining. The developmental patterns of these isozyme systems appear to be the result of the differential expression of the multiple gene loci. Isozymic forms of glucosephosphate isomerase (GPI‐A2), malate dehydrogenase (MDH‐A2), and creatine kinase (CK‐C2) were present in most differentiated tissues, in the unfertilized egg, and in all stages of embryonic development. Closely homologous forms of these isozymes (GPI‐B2, MDH‐B2, and CK‐A2) were expressed predominantly in skeletal muscle and were first detected at around the time of hatching (38‐42 hours). The similar temporal and spatial patterns of gene expressions for the GPI, LDH, MDH, and CK loci suggest that the duplicate loci encoding isozymes, diverged in their regulation to patterns of differential gene expression which are similar for each enzyme system.
The effect of metabolites of testosterone on the development of fertilizing ability by spermatozoa in the epididymis of castrated hamsters
Authors: Lubicz‐Nawrocki C. M. 
Published: June 2005

AbstractThe effects, of testosterone, 17βT‐hydroxy‐5α‐androstane‐3‐one (5α‐dihydrotestosterone; 5α‐DHT), 5α‐androstane‐3α, 17βT‐diol (3α‐androstanediol; 3α‐diol) and 5α‐androstane‐3βT, 17βT‐diol (3βT‐androstanediol; 3βT‐diol) on the development of fertilizing ability by spermatozoa in the epididymis were compared in castrated hamsters. The left corpus epididymidis was ligated for 14 days in intact and castrated animals to prevent the in‐flow of spermatozoa into the cauda epididymidis and the ductuli efferentes were bilaterally ligated. The fertilization rate of spermatozoa in the left cauda epididymidis of control animals decreased to 71.1% after 14 days whereas that of spermatozoa in the unobstructed right cauda epididymidis remained at the control level of 100%. After castration, 50 μg testosterone, 25 μg 5α‐DHT and only 9 μg 3α‐diol/day were the minimal doses that facilitated normal development of fertilizing ability but 75 μg testosterone, 37.5 μg 5α‐DHT and 12.5 μg 3α‐diol/day were required to maintain sperm survival at the control level. However, 3βT‐diol was ineffective for both sperm maturation and survival.