bluuebunny/crossref_metadata_2025_split huggingface dataset:
Variation and its causation in earthworm regeneration
Authors: Moment Gairdner B. 
Published: June 2005

AbstractThe coefficient of variation for the number of segments regenerated posteriorly by earthworms (Eisenia foetida) rarely exceeds 10 but the range may be over 100% of the mean. The manner of wound healing after transection (open or enteroparietal vs. closed or cicatricial) can not be responsible for the variation since under the conditions of these experiments all worms healed in the open manner. The angle of transection can be varied widely without any measurable effect on the number of segments regenerated. However, when the cut leaves a piece of ventral body wall and nerve cord extending posteriorly, the mortality is greatly increased and the number of segments formed by the survivors greatly reduced.Three successive regenerations in the same individuals revealed statistically highly significant consistencies indicating a genetic factor behind variation in segment number. Data from wild populations in similar but widely separated sites and also the large number of segments regenerated by individuals with initially very large numbers of segments all support the view that these worms are genetically heterogeneous regarding segment number. However, the effect of these genetic factors cannot be great.Bilateral asymmetry in number of segments regenerated indicates that the counting mechanism underlying variation can hardly be humoral because both blood and coelomic fluid are common to both sides of the body.
Denervation‐induced changes in soluble protein content during forelimb regeneration in the adult newt, Notophthalmus viridescens
Authors: Dearlove George E. , Stocum David L. 
Published: June 2005

AbstractDenervation‐induced alterations in the composition of the soluble protein population of various stages of forelimb regenerates in the adult newt were examined. Denervation alters the normal protein arrays in three ways: (1) proteins may be eliminated from an array, (2) proteins not normally present in an array may be induced to appear, and (3) proteins unique to denervated regenerates may appear in an array. The character of the denervation‐induced alteration at five days post‐amputation is basically different from that at later stages of regeneration. The stages during which the regenerate is becoming independent of the nerve for its morphogenetic activity are the ones in which the protein profiles are the most drastically altered. Morphogenetic independence of the nerve therefore does not require the synthesis of nerve‐dependent proteins, and it is concluded that nerve independence is a property generated by the production of a critical number of blastema cells. Nerve‐dependent proteins are required for the mitotic activity which leads to attainment of the critical mass, and the failure of denervated early regenerates to continue regeneration may be due solely to mitotic inhibition.
Oxygen consumptions of interscapular brown adipose tissue homogenates from two species of Peromyscus raised in different thermal environments
Authors: Mason Elliott B. , Prychodko William 
Published: June 2005

AbstractThe oxygen uptakes of interscapular brown adipose tissue sucrose homogenates from two species of Peromyscus that were raised in the laboratory at environmental temperatures of 5 °C, 23 °C, and 33 °C were measured by direct Warburg manometry with β‐hydroxybutyrate as substrate. Determinations were carried out at 37 °C on homogenates made from the tissues of animals remaining at the temperatures at which they were raised as well as on homogenates made from the tissues of animals that had been exposed for ninety minutes to the other temperatures of the study.Homogenates made from the interscapular brown adipose tissues of the northern species, P. maniculatus bairdii, raised at 23 °C and 33 °C consumed comparatively small amounts of oxygen, but tissue homogenate oxygen uptakes were significantly higher when P. maniculatus bairdii raised at 23 °C and 33 °C were exposed for short periods to 5 °C. Homogenates made from the interscapular brown adipose tissues of the southern species, P. polionotus, raised at 33 °C consumed small amounts of oxygen, but tissue homogenate oxygen uptakes were significantly higher following short term exposures of P. polionotus raised at 33 °C to both 5 °C and 23 °C.The comparatively high oxygen uptakes of homogenates made from the interscapular brown adipose tissues of both species raised at 5 °C and P. polionotus raised at 23 °C did not decrease when animals raised under these conditions were exposed for short periods to warmer environments.The results of the study indicate a cold adaptive role for interscapular brown adipose tissue that is consistent with the events of temperature acclimation in rodents as well as the fact that species specific differences in homogenate oxygen uptakes appear to be representative of genetically based environmental adaptations.
Melanocyte developmental genetics: Biphasic control of dopa oxidase activity by the E locus of the fowl
Authors: Carver Virginia H. , Brumbaugh John A. 
Published: June 2005

AbstractAliquots of developing feather papillae isolates were measured for oxygen consumption before and after incubation in the substrate, L‐dopa. Net oxidation (dopa minus basal) indicated the amount of L‐dopa oxidized by melanocytes.The albino‐like mutant ey/ey c/c showed minimal net oxidation when compared to its counterpart ey/ey +C/+C. This shows that the c mutation severely restricts dopa oxidase activity.The eumelanic genotype (E/E) had high net oxidation at stage 34 which regressed to a low value by stage 38. The pheomelanic‐producing genotype (ey/ey) had a low net oxidation at stage 34 which progressed to a high value by stage 38. Dopa oxidase activity in the eumelanin and pheomelanin producing genotype (standard; +E/ +E) was biphasic. Cells from these embryos had high net oxidation at both stages 34 and 38 and a low value at stage 36. High net oxidation at stage 34 in E/E and +E/+E seem associated with eumelanogenesis, while the high net oxidation at stage 38 in +E/+E and ey/ey is thought to be related to pheomelanogenesis.L‐dopa substrate utilization values were also completed for the heterozygote E/ey to determine if differences were detectable between this genotype and its respective homozygotes. The heterozygote net oxidation resembled E/E in pattern but at about one‐half the E/E values.The data are discussed in terms of the E locus as a possible control gene locus which determines whether eumelanin or pheomelanin is synthesized.
The effects of epilation and hormones on the activity of rat hair follicles
Authors: Hale Patricia A. , Ebling F. J. 
Published: June 2005

AbstractThe growth of hair from epilated and non‐epilated areas of rats receiving a variety of hormonal treatments was investigated by pulse‐labelling with 35S‐cystine. While epilation at certain stages of the spontaneous cycle may rephase follicular activity, it did not affect the length, rate or duration of growth of the hairs which erupted subsequently, either in untreated or hormone‐treated rats.Thyroxine shortened the active as well as the resting phase of the follicular cycle. It also increased the growth rate, so that hairs were ultimately the same length as those from untreated animals. Estradiol slightly shortened the duration of the active phase, even though the complete cycle was prolonged. It also decreased the hair growth rate. When administered simultaneously, estradiol and thyroxine exerted their effects independently.
Eye disk differentiation in the wax moth: Induction in vitro
Authors: Woolever Patricia , Pipa Rudolph L. 
Published: June 2005

AbstractEcdysterone‐induced differentiation of Galleria mellonella compound eyes in vitro is critically dependent on the age of the donor. It is greatest in explants from young prepupae, decreases with increasing donor age, and is absent in explants from 4–6 hour pupae. Failure of eye disks from pupae to differentiate in vitro seems to be the consequence of exposing them to culture conditions at a susceptible time in their development for, unlike eye disks from prepupae, they do not develop when removed from the medium and implanted into competent hosts. The explants most responsive in vitro are more liable to submerge, with resulting inhibition of development.Three media allow differentiation of adult eye structures, and one of these is suitable without adding macromolecular compounds. Ecdysterone is essential, and will elicit ommatidia formation when it is added to the medium at concentrations ranging from 0.1–20 μg/ml. Rubrosterone is ineffective at 1.0 μ/ml of medium.In the best‐differentiated explants each ommatidium consists of 8–10 pigmented retinal cells surrounding a rhabdom‐like core, and their axons can be traced to an enlarged optic nerve. Crystalline cones, adult cuticle in the form of facets (corneal lenses), and pigment cells also are formed.
The changes in cell shape during pigment migration in melanophores of a teleost, Oryzias latipes
Authors: Obika Masataka 
Published: June 2005

AbstractThe changes in cell shape of fish melanophores during pigment displacement, and the effects of colchicine and cytochalasin B on the surface morphology were studied by scanning electron microscopy. Dispersed melanophores are generally flat, with thick radiating dendritic processes. Aggregated melanophores are characterized by their swollen, hemispherical centrospheres and thin, collapsed dendrites. Colchicine induces a flattening of the entire surface of the cell while cytochalasin migration B elicits the swelling of the centrosphere accompanied by a partial migration (aggregation) of melanosomes.
Induction of nuclear breakdown and meiosis in Spisula solidissima oocytes by calcium ionophore
Authors: Schuetz Allen W. 
Published: June 2005

AbstractInduction of germinal vesicle breakdown and reinitiation of the meiotic process resulted following exposure of immature Spisula solidissima oocytes to divalent ionophore A23187. Meiosis continued to completion in the presence of the ionophore; however, parthenogenetic development of the gametes did not occur. Incubation of oocytes in calcium deficient media (Ca++free or Ca++Mg++free seawater) but not Mg++ free seawater inhibited ionophore induced maturation. Effects of calcium deficiency were reversible. The results suggest that nuclear disintegration and the meiotic process induced by sperm are mediated by ionic stimuli and that the establishment of meiotic arrest is linked to the availability of calcium with in the oocyte.
Development and life cycle of the parthenogenetically activated sea urchin embryo
Authors: Brandriff B. , Hinegardner R. T. , Steinhardt R. 
Published: June 2005

AbstractA method is reported for inducing parthenogenetic development in eggs of the sea urchinLytechinus pictus, a species which previously could not be artificially activated. NH4OH or the calcium ionophore A23187 are used as activating agents followed by hypertonic treatment. The ionophore is superior in activating large numbers of unfertilized eggs, whereas NH4OH produces a larger percent of embryos able to undergo gastrulation. Both feeding larvae and urchins arising from these artificially activated eggs are diploid. All individuals in which sex has been identified have been female. The viability of these completely homozygous organisms is low compared to their fertilized counterparts.
Ontogenetic expression of larval and adult hemoglobin phenotypes in the intergeneric salmonid hybrids
Authors: Iuchi Ichiro , Suzuki Ryo , Yamagami Kenjiro 
Published: June 2005

AbstractOntogeny of the hemoglobins of Honmasu (Oncorhynchus rhodurus, HXH), brook trout (Salvelinus fontinalis, BXB) and their reciprocal hybrids (HXB and BXH) was examined electrophoretically as well as spectrophotometrically. All of these fish have electrophoretically distinct larval and adult type hemoglobins and the transition from one type to the other occurred early during post‐hatching development.In the case of larval hemoglobins, the electrophoretic pattern of a hybrid, BXH, resembled that of the maternal parent, brook trout (BXB), while the hemoglobin of the reciprocal hybrid, HXB, differed markedly from that of the maternal parent, Honmasu (HXH), in that it possesses a diffuse pattern. Spectrophotometric examinations indicated that this was mostly methemoglobin.Adult type hemoglobins at more advanced stages of both hybrids were electrophoretically resolved into the parental hemoglobins. However, no “hybrid” hemoglobins were detected.Because there was abnormal hemoglobin formation in the larval erythrocytes (erythrocytes L) of the HXB hybrid, and then normal hemoglobin synthesis in the adult erythrocytes (erythrocytes A) of the same fish at later developmental stages, it appears that the paternal effects upon the hemoglobin differed in these two erythroid cell lines of the developing trout.
DNA synthesis during lens regeneration in larval Xenopus laevis
Authors: Waggoner Phillip R. , Reyer Randall W. 
Published: June 2005

AbstractLarvae of Xenopus laevis at stages 50–53 were lentectomized and then injected with tritiated thymidine at various times after lentectomy. In Series I, the animals were injected 1, 2, 3, 4, 6, 8, 10, 12, 15, or 17 days after lens removal and fixed three hours after injection. Autoradiographs of serial cross sections through the eyes were prepared. Increased incorporation of thymidine in the cells of the regenerating lens was first observed two days (stage 2) after lentectomy. All of the cells of the lens vesicle incorporated H3‐thymidine until stage 4 at which time the cells in the inner wall of the vesicle began to differentiate into lens fibers. Labelling then became restricted to the peripheral cells (prospective lens epithelium and prospective lens fibers). At stage 5 of regeneration, only cells of the lens epithelium incorporated H3‐thymidine. In Series II, animals injected three or four days after lentectomy were fixed daily from one to seven days after injection. Many stage 3 and stage 4 regenerates were recovered with label throughout and stage 5 regenerates were found, seven days after injection, with label over the lens fibers as well as over the lens epithelium.
Composition of fluid from the notochordal canal of the coelacanth,Latimeria chalumnae
Authors: Griffith Robert W. , Mathews Martin B. , Umminger Bruce L. , Grant Blake F. , Pang Peter K. T. , Thomson Keith S. , Pickford Grace E. 
Published: June 2005

AbstractFluid from the notochordal canal of the coelacanth,Latimeria chalumnae, was analyzed for major inorganic and organic constituents and compared with blood serum from the same fish. Significantly or suggestively lower levels of sodium, magnesium, calcium, bicarbonate, sulfate, total carbohydrates, glucose, lactate, cholesterol, bound phosphate and total proteins were found in notochordal fluid than in serum, whereas potassium, chloride, urea, trimethylamine oxide, and total free amino acids were higher and inorganic phosphorus essentially identical. Osmolarity of notochordal fluid (1058 mOsm) exceeds that of serum (942 mOsm). A whitish precipitate in the fluid consisted of a matrix of fibers 100 Å in diameter and of indefinite length. It resembled a sialoglycoprotein in composition and was stabilized by disulfide bonds. The fluid contained cellular debris.
Influence of antigen dose on antibody production of intact and splenectomised Xenopus laevis
Authors: Collie Madeleine H. , Turner Rodney J. 
Published: June 2005

AbstractAntigen persistence and serum antibody production in intact Xenopus were monitored using human gamma globulin (HGG), in adjuvant, in various immunisation schedules. Retention of HGG in spleen and serum was directly related to the quantity injected. However, antibody responses to a dose range between 1 μg‐6 mg antigen were similar in intensity. These were detected in the serum two weeks after injection and at this stage were exclusively mercapto‐ethanol (ME) sensitive; ME‐resistant antibodies had appeared by four weeks. No antibodies were detected below a dose of 100 ng HGG.The effect of splenectomy on antibody levels was tested using HGG/adjuvant or sheep erythrocytes (SRBC) in saline. Splenectomised toads showed impairment of antibody responses only to threshold doses of HGG (100 ng) but to a wider range of SRBC doses.
Fine structure of the zona pellucida of unfertilized egg cells and embryos
Authors: Barańska Wanda , Konwiński Marian , Kujawa Marek 
Published: June 2005

AbstractThe fine structure of the zona pellucida of mouse unfertilized egg cells and of mouse embryos was investigated. In addition to standard fixation for electron microscopy, fixation with an addition of ruthenium red was used and found to be especially valuable for the purpose of studying the zona pellucida.The zona pellucida of unfertilized egg cells and of embryos consisted mainly of fibrillar and granular material. There were two layers: a thicker internal and a denser external layer in the zona pellucida of the unfertilized egg cells. The zona pellucida of embryos had, in addition to these two layers, a coarsegrained intimal layer inside the internal layer and a fine‐grained peripheral layer outside the external layer. The intimal layer seems to be the product of cortical reaction whereas the peripheral layer can be accumulated and modified during the passage of the embryo through the female genital tract. The influence of developmental events and environmental factors on the fine structure of zona pellucida was discussed.
Cellular basis for the production and secretion of the hatching enzyme by frog embryos
Authors: Yoshizaki Norio , Katagiri Chiaki 
Published: June 2005

AbstractStage 17, 19, and 21 embryos of the grass frog, Rana chensinensis, were deprived of their envelopes, cultured for 36 hours, and the proteolytic activity of the culture media was determined. The activity is low during stages 17–19, increases sharply during stages 19–21, and remains at a high level during stages 21, 22. Comparison of the media in which the embryonic halves were cultured revealed that the secretion of the enzyme is dependent on the anterior part of the embryo. Embryonic extracts showed no significant activity at any stages examined. Culture of the epidermal explants from different embryonic regions proved further that the enzyme secretion is restricted in the dorsal frontal portion where a particular type of cells is predominant.In the tailbud embryo, large, flask‐shaped epidermal cells, designated as the hatching gland cells (HGCs), are mostly distributed in the dorsal frontal region, and in small number along the dorsal mid‐line. Electron microscopically, the HGC is characterized by prominent microvilli at the apical cell surface, a number of apically localized, membrane‐limited secretory granules, well‐developed Golgi complexes, as well as an abundance of rough‐surfaced endoplasmic reticula. The differentiation of HGC is first discernible at stage 17, and the cell acquires its histotypic characteristics at stage 18. The cell continues to synthesize and secrete granules during stages 18–21 and undergoes gradual regression after the hatching stage, accompanied by the formation of an elaborate phagolysosome within the cell.The evidence presented strongly indicates that HGC is a specific epidermal cell adapted for synthesizing and secreting the hatching enzyme in the prehatched frog embryos.
Elimination of 137Cs and 59Fe and its relationship to metabolic rates of wild small rodents
Authors: Baker Charles E. , Dunaway Paul B. 
Published: June 2005

AbstractElimination of 137Cs and 59Fe by three species of wild rodents was measured in laboratory and field experiments to determine whether excretion rates of these nuclides are influenced directly by general metabolic (CO2 production) rates. Sigmodon hispidus and Peromyscus leucopus were used in both field and laboratory experiments, and Reithrodontomys humulis was investigated only in the laboratory.Final‐component biological half‐lives (Tb) of 59Fe for Sigmodon averaged 108 days in winter, 144 days in spring, and means ranged from 176 to 242 days under various laboratory conditions (ambient temperature, cold‐exposure, irradiation, and chemical metabolic inhibition); for Peromyscus, values were 50 days in winter, 47 days in spring, and 289 days (at ambient temperature only) in the laboratory; for Reithrodontomys mean values ranged from 121 to 178 days at different laboratory treatment levels.Biological half‐lives of final‐component 137Cs elimination for Sigmodon averaged 7.5 days in winter, 7.9 days in spring, and means ranged from 7.7 to 8.6 days at the different treatment levels in the laboratory. Laboratory mean values for Reithrodontomys ranged from 3.5 to 3.9 days. For Peromyscus, Tb values averaged 3.4 days in winter, 3.6 days in spring, and 3.5 days in the laboratory.The data suggested that elimination of 59Fe is influenced by metabolic rates of rodents in the field, but laboratory experiments were unable to demonstrate any predictable relationship. Neither did the rate of final‐component 137Cs loss from rodents appear to be influenced by metabolic rate in the laboratory or in the field.However, final‐component Y‐axis intercept values of 137Cs exhibited a linear correlation with metabolic rates, and equations were derived from these intercept values to predict metabolism in the field for two species: for Sigmodon, Daily Average CO2 Production (ml/hr/g, STP) [5.24–0.9172 (logea)] [0.886]; and for Reithrodontomys, = [12.51–1.80 (logea)] [0.886].
Effect of UV on cleavage of Xenopus laevis
Authors: Beal Clayton M. , Dixon K. E. 
Published: June 2005

AbstractUV irradiation of the vegetal pole of stage 2 X. laevis embryos with doses of 6000–18000 ergs/mm2 delayed or inhibited cytokinesis in the vegetal hemisphere. Nuclear division continued so that a syncytium was formed, the size and persistence of which depended on the dose. Embryos which received a low UV dose were subsequently able to recover whereas embryos receiving a high dose were unable to gastrulate successfully. The implications for investigations into the role of cytoplasmic determinants are discussed.
Effects of parathyroidectomy on calcium and sodium concentrations of serum and coelomic fluid in bullfrog tadpoles
Authors: Sasyama Yuichi , Oguro Chitaru 
Published: June 2005

AbstractParathyroidectomy of larval and metamorphosing tadpoles of Rana catesbeiana caused significant decrease in Ca concentrations in serum and coelomic fluid, although their Na levels did not show significant changes. These results suggest that the parathyroid gland of the tadpole plays an important role in the elevation of Ca level in larval stages as well as in adults.
Non‐glial phagocytes within the degenerating optic nerve of the newt (Triturus viridescens)
Authors: Turner James E. 
Published: June 2005

AbstractTwo non‐glial phagocytes were found to participate along with ependymoglial cells in Wallerian degeneration of the severed optic nerve of the newt (Triturus viridescens). The first type of non‐glial cell (a polymorphonuclear phagocyte) was positively identified as a neutrophil and participates in the early stages of degeneration. Cells of this type make a brief appearance, reaching a peak by the second postoperative day (2 p.o.d.), and quickly diminish until few can be found by 4 p.o.d. Neutrophils invade the degenerating optic nerve from surrounding connective tissue spaces, most likely, through channels which penetrate the nerve parenchyma.The second type of non‐glial cell is an invading mononuclear phagocyte which exhibits characteristics of microglial cells reported in other vertebrate species. Such cells appear in the nerve much later than the neutrophils and towards the end of Wallerian degeneration (6–10 p.o.d.). Their mode of entry and exit appears to be the same as that reported for neutrophils.The neutrophils and microglial‐like, mononuclear phagocytes may serve to supplement the histolytic action of the ependymoglial cells, picking up scattered fragments of degenerating myelin and axons.