bluuebunny/crossref_metadata_2025_split huggingface dataset:
An attempt to reconstruct evolutionary changes in the cellular DNA content of lungfish
Authors: Thomson Keith Stewart 
Published: June 2005

AbstractLiving lungfish (Osteichthyes: Dipnoi) are known to have a very large cell size and unusually large quantitities of DNA per cell (up to 40 times the mammalian content). The pattern of evolution of cell size in fossil Dipnoi has been examined in order to see what light it might possibly shed on the question of the origin and evolutionary significance of DNA multiplication in Dipnoi. In the Devonian, cell size was low and it increased only in the Carboniferous when the major dipnoan morphological and taxonomic diversifications were ebbing. If it can be shown that there is a functional relationship between cell size and DNA content, then the data suggest that increase in cellular DNA content have a retarding rather than stimulating effect on dipnoan evolution. Since large cell size and (by inference) high cellular DNA content are not a primary feature of the dipnoan stock, it is suggested that in those other vertebrates, such as certain amphibians, which show the same phenomenon, it is also a secondary feature.
The effects of nerve growth factor on bullfrog tadpoles (Rana catesbiana) after limb amputation
Authors: Weis Judith S. 
Published: June 2005

AbstractTadpoles of the bullfrog, Rana catesbiana, lose the ability to regenerate limbs at a very early stage of development. Non‐regenerating limbs either show rapid healing of connective tissue over the cut surface with no breakdown of skeletal structures, or else show dedifferentiative processes in the cartilage but the rudimentary blastema formed does not proliferate, and becomes separated from the epidermis by the regrowth of the connective tissue layer. This condition is termed the “critical stage.” When tadpoles were treated with NGF, enlargement of spinal ganglia resulted due to an increase in cell number. The density of nerve fibers in the limbs was likewise increased. This increase in nerve supply to the limbs resulted in a greater incidence of critical stage limbs over non‐regenerating ones, and in several cases, produced limbs which appeared histologically to be, in fact, regenerating.
The haploid syndrome in isogenic haploid frog embryos of Rana pipiens derived by nuclear transplantation
Authors: Dasgupta Sanjoy , Matsumoto Lloyd 
Published: June 2005

AbstractThe majority of haploid frogs are non‐viable and few survive past early larval stages. While animals vary with respect to specific abnormalities, they succumb to the variety of defects which collectively comprise the haploid syndrome. This poor viability has been ascribed to unmasked lethal and semi‐lethal genes or to alterations in the nucleocytoplasmic ratio. This investigation was designed to test these hypotheses by determining the uniformity of anomalies in clones of isogenic haploid embryos.Animal hemisphere nuclei of stage 10 androgenetic haploids of Rana pipiens were transplanted into activated and enucleated eggs of uniform size. Haploid embryos were selected from eggs whose cleavage times coincided with those of the fertilized controls. Genetically identical haploid embryos displayed differences in the variety as well as the severity of abnormalities. Thus, specific lethal genes are not responsible for the variability in defects seen in the haploid syndrome. We ascribe haploid inviability and variations within isogenic clones to a lack of heterozygosity of the haploid nucleus with resultant inability of the haploid nucleus to function in a heterogeneous environment, i.e., the egg cytoplasm.
Recovery and abscopal effects after inhibitory x‐irradiation in earthworm regeneration
Authors: Moment Gairdner B. 
Published: June 2005

AbstractA seven step series of whole body irradiations beginning with 1,872 R and ending with 20,000 R showed that 10,000 R is not sufficient to block posterior regeneration from the fiftieth segment in the barnyard earthworm, Eisenia foetida but that 20,000 R is completely effective.With partial body irradiation at 20,000 or 30,000 R, if the five segments adjacent to the cut surface are exposed and the rest of the body shielded, there is no regeneration by the end of four weeks when controls have regenerated a mean of 34 segments and a minimum of 23 and stopped forming new ones. At the end of seven or more weeks all the partially irradiated worms had recovered and regenerated up to means of 17.3, 20.0, and even 26.3 segments.An abscopal effect was clearly evident in worms in which the first 40 segments were irradiated and the rest of the body, including the ten segments adjacent to the cut surface, shielded. All such worms regenerated without appreciable delay but markedly fewer segments than the controls. The question then arises as to why regenerating blastemas which are fully competent to regenerate a mean of 25 segments do not continue to proliferate until they have formed about 35 like the controls.
Differential sensitivity to hibernation of early and late events in development of the immune response
Authors: Jaroslow Bernard N. , Serrell Beverly A. 
Published: June 2005

AbstractGround squirrels, Citellus tridecemlineatus, were immunized with a single intraperitoneal injection of sheep red cells four days before, two days before, during and upon arousal from hibernation. The number of antibody‐forming cells per spleen was determined at different times during 56 days of hibernation and during the first week following arousal. All phases of the response, i.e., latent period, proliferative phase, declining phase, were slowed during the hibernation period and we concluded that most of the development occurred during the short periods of spontaneous arousal. The latent period, as compared to the other phases, was the most sensitive to retardation by hibernation. We believe that the resumption of development of the immune response during this phase is relatively delayed upon arousal because the early differentiating cells entered a quiescent state better adapted to hibernation whereas the later cell types did not.
α‐tocopherol in males of the rotifer Asplanchna sieboldi: Its metabolism and its distribution in the testis and rudimentary gut
Authors: Gilbert John J. 
Published: June 2005

AbstractNew‐born males produced by mictic females induced and cultured with emulsified dl‐α‐tocopherol‐5‐methyl‐H3 were extracted with acetone. A thin‐layer chromatogram of the extracted residue was divided into 20 1‐cm fractions which were analyzed for radioactivity in a liquid scintillation spectrometer; 100% of the tritium‐labeled lipid co‐migrated with authentic α‐tocopherol. Since known α‐tocopherol metabolites have migration characteristics different from α‐tocopherol in the chromatography system used, it was concluded that only undegraded α‐tocopherol was present in the males.The efficiency of extraction of tritium label from 42 males was 89%, and 132 DPM were recovered from the thin‐layer chromatogram. Therefore, each male contained about 5 × 10−16 moles, 0.2 pg, or 107 molecules of α‐tocopherol.The distribution of tritium‐labeled α‐tocopherol in embryonic and new‐born males produced by mictic females induced and cultured with emulsified dl‐α‐tocopherol‐5‐methyl‐H3 was analyzed by autoradiography. Background‐corrected mean grain density values showed that, for two different new‐born males, the amount of label in the testis was 3.7 and 6.7 times that in the rudimentary gut. Grains over the testis appeared to be randomly distributed while those over the rudimentary gut were primarily over the periphery.A semi‐quantitative analysis of mictic females with male embryos in different stages of development showed that only in well differentiated males were grain densities over the testis noticeably greater than those over the rudimentary gut. In younger embryos grains appeared to be randomly distributed over the entire embryo. Grain densities over the rudimentary gut in males about to be born were much lower than those over embryos in earlier stages of development. These results, together with electron micrographs of the testis and rudimentary gut of new‐born male Asplanchna and information available on the subcellular distribution of α‐tocopherol in vertebrates and plants, suggest that during late development of the male embryo α‐tocopherol‐rich organelles such as mitochondria are lost from the degenerating tissue from which the rudimentary gut of the new‐born male is derived.The results obtained are consistent with the hypothesis that α‐tocopherol is essential for spermatogenesis or male fertility in A. sieboldi and that for this reason the species has evolved its requirement of α‐tocopherol for mictic female production.
Induced chimaerism by transplanting embryonic cells into mouse blastocysts
Authors: Moustafa Laila A. , Brinster R. L. 
Published: June 2005

AbstractEmbryonic synchronous and asynchronous cells were successfully transplanted into preimplanted mouse blastocysts. At 15–17 days of fetal development, 19% (32/167), 15% (20/130) and 3% (4/117) of the fetuses expressed chimaerism of the ocular pigmentation when transplanted cells were 0, 48, and 96 hours asynchronous respectively. At birth and during postnatal development, 15% (23/153) and 13% (14/111) of the young expressed chimaerism of ocular pigmentation, coat color, and/or functional germ lines when transplanted cells were 0 and 48 hours asynchronous respectively. Five animals from synchronous and two animals from asynchronous cell transplants were chimaeric in functional germ lines but resembled recipient blastocysts in phenotype color. One overtly chimaeric male had progeny with color phenotype of the albino donor cells only. This report provides evidence that transplanted asynchronous as well as synchronous embryonic cells do participate in the final structure of the embryo. In addition, the results of these studies suggest that the micrurgy and transplantation of the cells does not affect substantially subsequent development of the recipient blastocysts.
The influence of ovine follicle stimulating hormone (FSH) and luteinizing hormone (LH) on the male reproductive system and the skin of the mediterranean Blenniid fish Blennius sphinx (valenciennes)
Authors: Blüm Volker 
Published: June 2005

AbstractThe Mediterranean Blenniid fish Blennius sphinx has a unique male reproductive system: the testes lie close to voluminous lipid bodies through which the sperm must pass. The tubules, through which the sperm travel, lead to a collection duct opening ventrally into locally enlarged sperm ducts. These taper off caudally and join in an unpaired terminal section which opens into a genital papilla. Slightly posterior to the union, the duct forms two blind pouches extending laterally to the caudal third of the testes. In addition, during spawning, Blennius sphinx shows a glandular system of unknown function in the first and second spines of the anal fin.In this paper, the reactions of the sex‐linked structures described above, and of the mucous cells in the epidermis of post‐spawning fishes, to injections of mammalian FSH and LH are studied.
By LH‐treatment the proportion of the animals with fully active testes is increased from 36% (controls) to 83%.
The height of the lipid body is increased about 26% by LH‐injections, as compared with the controls. This effect is correlated with an increase in the size of the lipid vacuoles of about 28%.
In the epithelium of the paired portions of the sperm duct, LH promotes the formation of aldehyde fuchsin‐positive granules in the cells. The proportion of this type of secretion rises from 18% (controls) to 68% after LH‐treatment. In the terminal unpaired part of the sperm duct, within the genital papilla, the epithelium is thickened by about 38% by this hormone.
Injections of LH decrease the height of the blind pouch epithelium, which is well developed, and actively secreting in most of the controls. They also suppress secretion and vascularisation in this structure.
LH promotes the formation of the anal gland system, increasing the proportion of the animals with maximally developed glandular systems from 0% (untreated controls) or about 17% (H2O‐treated controls) to 91%. This effect is correlated with an increase of the diameter of the single glands of about 40%. This is also the case in FSH‐treated fishes (23%). The number of the mucous cells in the epidermis decreases by 46% and 45% after FSH‐ and LH‐treatment, respectively.
In no case were the effects strictly correlated with the hormone dose.
The problems of the action of mammalian gonadotrophins, especially FSH, in fishes; the possible functions of the organs associated with the male genital tract of Bl. Sphinx, and the possible role of the mucous cells in the osmoregulation of fishes are discussed.
The activity of microtubules and microfilaments in neurulation in the chick
Authors: Karfunkel Perry 
Published: June 2005

AbstractDuring neurulation, the cells of the chick neural anlage elongate and become wedge‐shaped. Microtubules are seen aligned parallel to the cells' long axes, and bands of microfilaments are seen in the cell apices. If stage 8 embryos are cultured in the presence of colchicine, the cells of the brain anlage round up and the neural folds move away from each other. In the posterior part of the neural anlage, cells fail to elongate, and neural folds never form in this region. If such embryos are cultured in the presence of cytochalasin B, the cells of the brain anlage remain elongate but the neural folds separate from each other. The cells of the posterior part of the neural anlage elongate in the presence of cytochalasin, but the neural folds never form in this region. These results constitute evidence that microtubules effect the cell elongation and microfilaments effect the apical constriction of cells which normally accompany neurulation. These changes in cell shape appear to be responsible for the elevation and mediad folding of the neural folds.
Skin allografts in the newt, Notopthalmus viridescens: Cessation of blood flow as an indicator of rejection,
Authors: Hightower James A. , St. Pierre Ronald L. 
Published: June 2005

AbstractHistological sections and surface views of skin allografts from newts were examined. It was determined that complete cessation of blood flow through the allografts was a valid indicator of graft rejection.The following sequence of events was detected within allografts as they were rejected; (1) primary vasodilation 8.4 ± 3.6 days after grafting; (2) re‐establishment of circulation at days 11.3 ± 3.5 after grafting; (3) signs of rejection (viz., secondary vasodilation, stasis and hemorrhage) at days 20.9 ± 5.0 after grafting, and (4) complete rejection at days 36.1 ± 7.0. There was no evidence of sexual dimorphism in any of the newts examined with regard to skin allograft rejection.
Deployment of maternal template during early amphibian embryogenesis
Authors: Malacinski George M. 
Published: June 2005

AbstractThe electrophoretic characteristics of the proteins synthesized during the early stages of Rana pipiens embryogenesis were determined. Very minor quantitative changes were observed in the spectrum of proteins synthesized during development from the unfertilized egg through the 32‐cell stage. At the mid‐ and late cleavage stages, however, a pronounced increase was observed in the rate of synthesis of some proteins which very previously synthesized at relatively low rates.The qualitative features of protein synthesis in early cleavage stage embryos which lacked functional chromosomes resembled control nucleated embryos at similar morphological stages; therefore the translation of maternal template appears to specify the types of proteins synthesized during those early stages of development. In partial blastulae derived from enucleated eggs, the increased rate of synthesis of specific proteins observed in control embryos was not detected. The deployment of specific maternal templates at the blastula stage seems to require the presence of functional chromosomes.
Gel filtration of the sperm attractants of some marine hydrozoa
Authors: Miller Richard L. 
Published: June 2005

AbstractElution patterns of sperm chemo‐attractants isolated from female hydroids of the genera Campanularia, Gonothyrea, Tubularia and Clava were obtained by comparative gel filtration chromatography. Generally one major and one minor peak of activity were obtained for each of the species used, except Gonothyrea which yielded two large active peaks. The Rf values of these peaks fall into two non‐overlapping groups. The first group consists of the major peak obtained from Campanularia calceolifera, the first major peak from Gonothyrea and the minor peak obtained from each of the three species of Tubularia, all of which have Rf values near 0.7. The second group consists of the major peaks from the three species of Tubularia, the second major peak from Gonothyrea, the minor peak from C. calceolifera, and the major peak from Clava, all of which have Rf values near 0.5. Separation of mixtures of some of the attractants was possible using this method.Correlation between chromatographic elution position and species‐specificity determined by testing the extracts from the various species against live sperm, is not perfect in all cases, in part, at least, because gel filtration is not capable of separations other than on the crude basis of molecular size. Gonothyrea and Campanularia calceolifera extracts and sperm show cross‐reactivity and their active agents elute together during chromatography. The same is true for the three species of Tubularia tested. However, the second Gonothyrea peak elutes at the same position as the major peak of Tubularia activity, but these genera do not attract each other's sperm. These results suggest that methods other than chemotaxis are used by many hydroids to prevent exposure of eggs to sperm from the wrong species and that more specific separation methods will have to be used to determine the molecular basis for chemotactic specificity in hydroids.
The antigenic pattern of the developing brain of the zebrafish, Brachydanio rerio
Authors: Singh Lakheram , Laale Hans W. 
Published: June 2005

AbstractDevelopmental stages, from eight cells to 28 days post‐hatching, of the zebrafish, Brachydanio rerio, were analysed by immunoelectrophoresis with unabsorbed and absorbed rabbit antiserum to adult zebrafish brain. From the earliest embryonic stage to the oldest post‐hatching stage tested, a developing antigenic pattern was recognizable. Six antigens, found to be consistently present in all stages, exhibited no observable variation in electrophoretic mobility or diffusion rates. Of four other antigens present in the earliest stage analysed, one appeared intermittently throughout subsequent developmental stages. Three antigens appeared consistently, but showed variations in electrophoretic mobility at different stages. Fourteen ‐antigens, two of which were transitory, appeared during development, adding to the complexity of the antigenic pattern. Including all stable and variant forms of antigens, a total of 30 antigens was detected from the earliest embryonic stage to the oldest post‐hatching stage tested.
Regulative development in the pulmonate gastropod, Lymnaea palustris, as determined by blastomere deletion experiments
Authors: Morrill John B. , Blair Claudia A. , Larsen William J. 
Published: June 2005

AbstractTo determine the regulative ability of Lymnaea eggs one or more cells were deleted by puncturing or shaking eggs at the 2−, 4−, 8− and 16‐cell stages. Normal snails developed from: one/two, three/four, and two/four embryos; from 8‐cell embryos in which one, two, or three cells of the first quartet of micromeres or one or two macromeres were deleted; and from 16‐cell stage embryos in which one cell of the second quartet of micromeres or one macromere was deleted. Only one/two embryos that cleaved as though they were whole eggs up to the 24‐cell stage developed normally. Normal development of other partial embryos was associated with partial cleavage. Developmental abnormalities of partial embryos included death in the cleavage period; arrested gastrulae; trochophores, or veligers; and abnormal snails with head malformations, everted stomodea, or conical shells.Comparing the results with deletion experiments in other molluscs and with deductions from descriptive studies on the Lymnaea egg, we propose that the regulative ability of partial embryos depends on the rearrangement of cells relative to the D macromere before inductive activities begin at or after the 24‐cell stage.
Role of islet tissue in the cold‐induced hyperglycemia of the killifish, Fundulus heteroclitus
Authors: Umminger Bruce L. , Bair Roy D. 
Published: June 2005

AbstractIslet tissue histology and serum glucose concentrations were examined in salt‐water‐adapted killifish, Fundulus heteroclitus, acclimated to 20°C and to − 1.5°C for one and ten days. Exposure to subzero temperatures produced a hyperglycemia accompanied by hypertrophy and degranulation of alpha cells in the islets and by atrophy of the islet beta cells with no changes in granulation. The cold‐induced hyperglycemia presumably resulted from an increase in circulating levels of glucagon and from a failure of the beta cells to release insulin.
Photoperiod and crowding effects on testicular serotonin metabolism and lack of effects on melatonin synthesis in Uinta ground squirrels (Spermophilus armatus)
Authors: Frehn John L. , Urry Ronald L. , Balph David F. , Ellis Legrande C. 
Published: June 2005

AbstractThe photoperiod (i.e., constant light vs a 14/10 hour light/dark cycle) and “physical” crowding (group caging) on Uinta ground squirrels (Spermophilus armatus) was investigated to ascertain what effects these two environmental parameters would have on testicular metabolism of serotonin (MAO activity) and melatonin synthesis by pineal glands in organ culture. Testicular MAO activity was decreased by both constant light and crowding. Melatonin synthesis was not significantly affected by either treatment. These data are consistent with the normal reproductive activity of unconfined ground squirrels where the testes normally develop while the animals are in their burrows under constant darkness. Failure of the pineal gland to respond to constant darkness appears to be an adaptation of the animal to eliminate this source of antigonadal activity that would serve to retard gonadal development while the animal is in constant darkness. Failure of the testes to respond to a 14/10 hour Light/Dark cycle indicates that the hypothalamus is insensitive to lighting as a triggering mechanism for initiating testicular development.
Use of chimeras to transmit lethal genes in the mouse and to demonstrate allelism of the two X‐linked male lethal genes jp and msd
Authors: Eicher Eva M. , Hoppe Peter C. 
Published: June 2005

AbstractThe uses of experimental chimeras to transmit lethal genes are discussed. As an example, the X‐linked lethal mutation jp was genetically transmitted by a chimeric male. This male produced abnormal offspring when bred to jpl + and msd/ + females. Thus, allelism of the mutations jp and msd is proven and the symbol for msd should be changed to jpmsd.