bluuebunny/crossref_metadata_2025_split huggingface dataset:
Gene action on proliferation and migration in the developing neural crest of black and white axolotls, Ambystoma mexicanum, Shaw
Authors: Borack Leonard I. 
Published: June 2005

AbstractThe mitotic index \documentclass{article}\pagestyle{empty}\begin{document}$ \left({\frac{{{\rm number\,of\,dividing\,cells}}}{{{\rm total\,number\,of\,cells}}}} \right) $\end{document} of the neural crest and its derivatives in situ was determined in serially‐sectioned embryos of the black (DD or Dd) and white (dd) strains of the Mexican axolotl, Ambystoma mexicanum, Shaw, to see whether the differences between the strains in the number and distribution of their initial complement of melanophores could be causally related to differences in the pattern of development of their respective neural crests.Prior to and during the initial appearance of melanophores, the mitotic index of the neural crest in situ in the black axolotl is significantly greater than in the white. Concommitantly, there are more crest cells in the black than in the white prior to crest cell migration. However, during the periods of maximum crest cell migration and initial appearance of melanophores, there are significantly more crest cells in situ in the white than in the black. These crest cells in situ in the white are clumped together mid‐dorsal to the neural tube, while in the black they show the dispersion typical of migrating crest cells.Following the initial appearance of melanophores, there are no differences between the strains in the number of melanophores dorsal to the neural tube and somites, but there are significantly more crest‐derived cells in this area in the black than in the white. The latter difference between the strains may be causally related to the significantly greater number of cells in the early spinal ganglia of the black axolotl than in the white.
Capacitation of hamster spermatozoa treated with rabbit tubal fluid or rabbit and bovine tubal cystic fluids
Authors: Iwamatsu T. , Chang M. C. 
Published: June 2005

AbstractThe induction of capacitationin vitroof hamster sperm was examined in the presence of rabbit tubal fluid or tubal cystic fluids of cow and rabbit. When mixed with recently‐ovulated eggs in Tyrode's solution containing rabbit tubal fluid, epididymal spermatozoa became capacitated and sperm penetration as well as the formation of pronuclei was observed in most eggs within three hours. Incubation of epididymal spermatozoa in the presence of tubal cystic fluid of rabbit or cow could induce the capacitation of hamster sperm, and sperm penetration was observed by insemination of the incubated sperm. By treatment with these fluids, especially those from rabbits and in the presence of sperm, the zona pellucida was elevated or dissolved. The factor(s) responsible for sperm capacitation and acting on the zona pellucida was relatively heat‐stable. The high incidence of polyspermy was probably due to the abnormal condition of the zona pellucida and the presence of numerous capacitated spermatozoa under the present experimental conditions.
The compensatory regeneration of the operculum of Hydroides norvegica: Identification of the inhibiting substance
Authors: Puccia Egidio , Durante Maria 
Published: June 2005

AbstractIn the polychete Hydroides norvegica there are two opercula with different degrees of organization: one is completely developed and functional, the other, present only in rudimentary outline. The latter only begins to develop when the functional operculum is removed. It was observed that in the whole body of the Hydroides, but particularly in the functional operculum, there is a substance which inhibits the development of the rudimental operculum. This substance was purified in order to determine its chemical nature.From preparation of opercular homogenates we chemically separated numerous fractions, each of which was tested for inhibitory activity and chemical and physical properties. The inhibitor under study proved to be soluble in aqueous solutions, heat resistant, of low molecular weight, of an organic nature, anionic and aromatic. Finally it was chromatographically identified as 5′ adenosine monophosphate.
A new fate map for Salmo gairdneri
Authors: Ballard William W. 
Published: June 2005

AbstractChalk granules implanted among the cells of the stage 7 blasto‐disc are carried along with the cells to final location in the differentiating tissues and organs. The results, more often than not, are inconsistent with predictions suggested by an earlier fate map for Salmo (Pasteels, (36). Granules vertically thrust into a given spot on the blastodisc are usually carried to various levels of the trunk and to a variety of organs, presumably because cells at different depths of one spot and at different distances from the center are moving at different rates. Data from hundreds of such implants are assembled into charts showing the areas from which cells are drawn, to contribute to formation of the endoderm, notochord, five separate zones of the central nervous system, the head mesoderm, anterior and posterior trunk somites, tail somites, lateral plate, and heart. Using evidence of the overlapping and intergradation of these areas, as well as evidence from vital dyes when allowed to penetrate to various depths of the pregastrular blastodisc, a three‐dimensional fate map is synthesized for Salmo gairdneri, which is very different from the earlier map, but consistent with the previously reported patterns of morphogenetic movements in this species (Ballard, (73b). In contrast with the gastrulation of amphibia and birds, Salmo germ layers arise without any invagination, and there is at no time an anterior mesoderm‐free area. Previous efforts to generalize upon vertebrate gastrulation and its evolution within the phylum seem to have been premature.
Effect of hypophysectomy, isletectomy and ACTH on glycemia and hematocrit in the bullhead, Ictalurus melas
Authors: Chidambaram S. , Meyer R. K. , Hasler A. D. 
Published: June 2005

AbstractEffect of hypophysectomy, isletectomy and ACTH on glycemia and hematocrit in Ictalurus melas were studied. The mean blood glucose (BG) and hematocrit in intact untreated fish were found to be 69.65 mg/100 ml and 33.7% respectively. Following hypophysectomy there was a 73.1% decrease in BG and a 50% decrease in the hematocrit. Changes in sham‐operated controls were insignificant.Eight IU of porcine ACTH administered in two injections on days 6 and 8 post‐hypophysectomy increased the BG to pre‐hypophysectomy level and the hematocrit to 70% of its initial value on day 9, whereas in vehicle injected controls BG and hematocrit values remained at their post‐hypophysectomy level.Isletectomy caused hyperglycemia in all the experimental animals. It induced a net increase of 142.3% over the pretreatment BG compared to 5.2% increase in sham‐operated controls. Isletectomy unlike hypophysectomy did not produce any significant change in the hematocrit.
Studies on eye regeneration in a snail, Helix aspersa
Authors: Eakin Richard M. , Ferlatte Millie Miller 
Published: June 2005

AbstractPart I is a study of the fine structure of the regenerating optic tentacle of a pulmonate snail, Helix aspersa. Electron microscopy demonstrates marked similarity between regeneration and embryonic development of the eye and its photoreceptoral microvilli, lens‐forming secretory droplets, clear photic vesicles, neurites, pigment granules, and bundles of tonofilaments. A cell type, heretofore undescribed, prominent in the regeneration of the tentacle, is a pigmented interstitial cell. This cell is characterized, and its presumed role in the tentacle is discussed. Part II is an attempt to test the importance of nerve fibers in the induction of a regenerating eye in the newly formed epithelium of the outer tentacular sheath. Ligatures were placed around the inner tentacular sheath above the stumps of severed optic and tentacular nerves. No eye regenerated in snails with the ties in place, some as late as 90 days postoperative. The results suggest that nerve fibers exert an influence on the regeneration of the eye in Helix aspersa.
Enzyme patterns in mitochondria of mouse liver and heart muscle
Authors: Kistler Andreas , Weber Rudolf 
Published: June 2005

AbstractThe content of membrane‐bound (COX, SDH) and matrix enzymes (MDH, GOT, GDH) in mitochondria of heart muscle and liver of the mouse has been compared. Ageing of osmotically lysed liver mitochondria has little effect on enzyme stability, except for GDH the activity of which drops by 40%. Purification of liver mitochondria by sucrose density‐gradient centrifugation results in a loss of COX‐activity of 70%, but has no effect on cytochrome aa3 content. Heart muscle mitochondria are characterized by higher activities (per unit mitochondrial protein) of SDH, MDH, GOT and cytochrome aa3 content, but lower levels of GDH activity as compared to liver mitochondria. When referred to cytochrome aa3 content “constant activity proportions” are noted for SDH, MDH and GOT, whilst “specific activity proportions” are characteristic of GDH. The enzyme patterns are compared to the ultrastructure of these mitochondria.
An analysis of urodelian retinal regeneration: III. Degradation of extruded melanin granules in Notophthalmus viridescens
Authors: Keefe J. Richard 
Published: June 2005

AbstractThe fine structural features of a retinal: melanophage, observed in degenerating retinae of Notophthalmus viridescens is described. The melanophage, believed to originate from the vascular supply, serves for the stepwise degradation of extruded single melanin granules from cellular elements of the pigment epithelium which are forming the regenerated retina.
Daily variations in the effects of handling on fat storage and testicular weights in several vertebrates
Authors: Meier Albert H. , Trobec Terry N. , Haymaker Holley G. , MacGregor Robert , Russo Albert C. 
Published: June 2005

AbstractHandling disturbances alone repeated daily for ten days caused marked changes in the fat stores of a fish, Fundulus chrysotus, a lizard, Anolis carolinensis, a quail, Coturnix c. japonica, and a mouse, Mus musculus. Repeated handling also caused changes in the weights of the male reproductive organs in the lizard and mouse. Whether the effects of handling were stimulatory, inhibitory, or of no effect depended on the time of the disturbance with respect to a daily 16‐hour photoperiod. The results should serve as a warning to investigators in many areas in which experimental subjects are handled in one way or another at the same time each day.
Insulin content and B cell morphology of the pancreas after chronic insulin treatment in a lizard
Authors: Rhoten William B. 
Published: June 2005

AbstractDaily intraperitoneal injections of insulin into the lizard Anolis carolinensis leads to a reduced immunoreactive insulin (IRI) content of the splenic lobe of the pancreas. This reduction correlates with the observed morphologic changes. On the sixteenth day of injection the IRI content is reduced by more than 50% of the control value. At this time, the aldehyde fuchsin‐reactivity of the B cells is markedly diminished and the diameter of the B cell secretory granules, as determined by electron microscopy, is reduced by approximately 125 nm. Since the number of secretory granules after 16 daily injections of insulin does not appear to be diminished, the reduced size and stainability suggest that the remaining intragranular component is predominantly a non‐insulin matrix material. These observations indicate the existence of a quantitative relationship between the size of the B granules and the insulin content of the pancreas.
Protein incorporation by isolated amphibian oocytes III. Optimum incubation conditions
Authors: Wallace R. A. , Jared D. W. , Dumont J. N. , Sega Marsha W. 
Published: June 2005

AbstractAvailable evidence indicates that protein incorporation by amphibian oocytes is mediated through a process of micropinocytosis. Oocytes incubated under our standard conditions sequester protein at a constant rate for at least 24 hours and appear to maintain approximately the same level of micropinocytosis as that observed in situ. Protein uptake is markedly sensitive to temperature and the ionic composition of the medium, with calcium being a particularly important component. Magnesium, phosphate, and additional energy sources are of only minor significance. Based on these observations, several slightly improved reformulations of the standard incubation medium are provided.
The post‐hatching transition of erythrocytes from larval to adult type in the rainbow trout, Salmo gairdnerii irideus
Authors: Iuchi Ichiro 
Published: June 2005

AbstractIn addition to typical, round disc‐like larval type erythrocytes (erythrocyte L) in pre‐hatching embryos as well as just‐hatched larva and the typical elliptic disc‐like adult type erythrocytes (erythrocyte A) in two‐year‐old fish, a third type of erythrocytes has been observed to appear in the peripheral blood of rainbow trout larvae during a short period (a few weeks) of erythrocyte transition from L to A. Analyses of the erythrocyte population at various stages of the transition have suggested that the third type erythrocytes may not be derived from erythrocyte L, but may be an independent population which will develop into erythrocyte A in the blood and therefore have been referred to as immature type erythrocyte A (erythrocyte ImA). Dynamics of erythrocyte replacement from one to the others during post‐hatching development is characterized by the rapid decrease in erythrocyte L and the compensatory appearance of erythrocyte ImA, which then will develop into the mature erythrocyte A in the peripheral blood.The three types of erythrocytes differ with respect to sensitivity to osmotic shock. A difference has also been observed between erythrocyte L and erythrocyte A including A concerning reactivity with concanavalin A and wheat germ agglutinin.
Effect of adiposectomy and feeding level on FSH‐induced testicular growth in male lizards Anolis carolinensis (Reptilia: Iguanidae)
Authors: Cuellar Hector S. 
Published: June 2005

AbstractExperiment 1. At 32°C and with a plentiful food supply the testes of Anolis carolinensis injected with 25 μg FSH for 11 days grow in the absence of fat bodies. The same dosage of FSH did not influence fat body weight in the sham‐operated animals.Experiment 2. Animals injected with FSH for 25 days and given either one mealworm/day, one worm every five days, or no food did not differ significantly in body weight from one another. The livers and fat bodies of those groups receiving one mealworm/day or one every five days were drastically reduced in size. The liver fat content was significantly greater in the adiposectomized group than in the sham‐operated group. The testes were greatly reduced in animals treated with saline and given one mealworm every five days or no food. The FSH‐treated groups had significantly larger testes than the saline‐treated groups and the initial control group. It is suggested that (1) in the absence of fat bodies the liver stores fat, (2) FSH may induce thirst or inhibit body water loss or both, and (3) conditions of insufficient diet may inhibit testes growth by shutting off or decreasing gonadotropin secretion.
Interactions between gametes and environment in the toad Xenopus laevis (Daudin) and their relationship to fertilization
Authors: Del Pino Eugenia M. 
Published: June 2005

AbstractThe Xenopus laevis egg jelly becomes swollen in different solutions: however; the degree of swelling of each of the three jelly layers and appearance vary depending on the medium. On eggs kept in a medium of low salt concentration, three sublayers of layer J‐3, the “J‐3 complex,” are visible. However, these sublayers cannot be distinguished in eggs hydrated in DeBoer's. Presence of the J‐3 complex is correlated with loss of egg fertilizability. Changes in the swelling of the jelly, disappearance of the J‐3 complex and regaining of egg fertilizability are brought about by brief exposures of the hydrated eggs to DeBoer's. The process that elicits these changes in the jelly was named “jelly reversal.” Jelly reversal is dependent on the solute concentration of the medium, is independent of pH and can be elicited by qualitatively different solutions. Non‐polar solutions act more slowly than those of polar solutes. Regaining of egg fertilizability is dependent on jelly reversal, nature of solute, solute concentration and pH. The phenomena of jelly reversal and regaining of egg fertilizability imply that specific ions of the jelly are needed for fertilization. Hydration of the jelly can form blocks to sperm entry, therefore, the block to polyspermy in Xenopus is not a single event.Layer J‐1 stains metachromatically with toluidine blue and incorporates 35S‐sulfate during its formation. Failure of eggs to regain fertilizability after reversal at low pH is correlated with diminished toluidine blue metachromasia of J‐1. Retention of staining was dependent upon the salt concentration of the medium.
The lonic permeability of the Amphibian oocyte in the presence or absence of external calcium
Authors: Tupper Joseph T. , Maloff Bruce L. 
Published: June 2005

AbstractThe membrane potential of the Rana oocyte, as determined by intracellular microelectrodes, ranges from approximately −40 to −70 mV (inside negative). Upon removal of external Ca, a large, rapid depolarization in membrane potential occurs. The depolarization is reversible by both Ca and Mg. In the presence of Ca, the magnitude of the membrane potential is primarily dependent on the K distribution across the oocyte membrane with a lesser but significant Na dependence. Upon Ca removal, the Na dependence is greatly increased, indicating an increased Na permeability. Direct measurements of Na, K and Cl permeability by tracer‐flux analysis indicate the following. In the presence of Ca the permeabilities are approximately: Na (1.0 × 10−6 cm/sec); K (5.6 × 10−6 cm/sec); Cl (1.4 × 10−6 cm/sec). Upon Ca removal the K and Cl permeabilities are not significantly altered. However, there is an approximately four‐fold increase in Na permeability (4.5 × 10−6 cm/sec). This increase explains the observed depolarization in membrane potential upon Ca removal. It has been suggested previously that Ca may regulate the in vivo depolarization observed during transition from oocyte to ovulated egg in the amphibian. The present experiments indicate that, if Ca does play a role, its role is not analogous to the in vitro effect on the oocyte, since the ovulated egg has reduced Na as well as K permeability.
Metabolic sources of ammonia in the earthworm, Lumbricus terrestris L
Authors: MacDonnell Paul C. , Tillinghast Edward K. 
Published: June 2005

AbstractThe earthworm Lumbricus terrestris is ammonotelic while feeding but becomes ureotelic with fasting.

The metabolic sources of ammonia nitrogen in feeding worms have been examined. Two deaminating enzymes, L‐serine dehydratase and 5′‐AMP deaminase, have been observed to be present in high activity. The latter enzyme was an order of magnitude more active than the former.
The activity of L‐serine dehydratase was modified by theophylline but not by cyclic AMP.
5′‐AMP deaminase appears to be an allosteric enzyme with ATP functioning as a positive modulator. The positive allosteric effector increases the apparent affinity of 5′‐AMP deaminase for its substrate while having no effect on the maximum velocity of the reaction.
Both enzymes were located predominantly in the gut tissue.
While neither enzyme decreased in activity with fasting their possible role in ammonia production is discussed.
Effects of pinealectomy and melatonin injections at different seasons on ovarian activity in the lizard Anolis carolinensis
Authors: Levey Irwin L. 
Published: June 2005

AbstractThe short‐term effects of pinealectomy and melatonin treatment on ovarian activity in the lizard, Anolis carolinensis were examined at various times of the year. Animals were maintained under short photoperiod (6L:18D) at a constant temperature of 31 ± 1°C.Destruction of the epiphysis by heat cautery in November and January caused significant follicular development within 14 days. Daily administration of 10 μg synthetic melatonin blocked ovarian stimulation resulting from pinealectomy. Ovarian sensitivity to pinealectomy decreased with the onset of seasonal reproductive activity and was absent at the end of the normal breeding season, i.e., September.These observations support the hypotheses that, under conditions of short photoperiod and high environmental temperature, (a) the pineal organ can modify ovarian activity in Anolis; (b) there exists a definite seasonal sensitivity to this influence; and (c) melatonin may be an active agent of pineal function.
Properties of rattlesnake shaker muscle
Authors: Martin James H. , Bagby Roland M. 
Published: June 2005

AbstractThe goals of this study were to learn something of the physiology of the rattlesnake's rattling mechanism and the mechanical properties of tension development. Using the rattlesnakes, Crotalus atrox and Crotalus scutulatus, it was found that the rattling motion is a complex oscillation rather than the simple back and forth motion often described. Rattling is accomplished by “doublet” contractions, i.e., if the shaker muscles on one side of the tail contract, then so do the muscles on the other side. The time interval between the two members of a doublet is temperature dependent and is the ultimate determinant of maximum rattling speed. The rattling is not produced by asynchronous type muscle such as found in insects. The isometric twitch is extremely fast at 18°C, and the contraction time is on the order of 8–10 msec. The rattlesnake shaker muscle at 18°C produces 0.3 kg/cm2 tension and has a twitch‐tetanus ratio of 0.19. The length‐tension curve for the active muscle is typical for skeletal muscle, but there is a larger passive resistance to stretch like that found in insect fibrillar flight muscle or cardiac muscle.
Maturation of spermatozoa in the rabbit epididymis: Effect of castration and testosterone replacement
Authors: Orgebin‐Crist M.‐C. 
Published: June 2005

AbstractRabbit epididymal spermatozoa gain their fertilizing ability upon reaching the distal corpus epididymidis. When prevented by ligatures from reaching this region, they become fertile in the proximal corpus after 24 hours in the intact male but not in the three‐day castrated male. Unilateral castration has no such effect. Testosterone propionate (2 mg/kg/day) prevents this effect of castration. Abnormalities in ova fertilized by spermatozoa from castrated males and castrated males receiving testosterone suggest that an adequate level of androgen is necessary not only for the spermatozoa to become fertile but, also, for support of the normal development of the ova.
Lactate dehydrogenase isozyme patterns of thirteen species of snakes
Authors: Schwantes Maria Luiza 
Published: June 2005

AbstractStarch gel electrophoresis patterns of lactate dehydrogenase (LDH) from various tissues of 13 species of snakes belonging to three families are described. At least five LDH isozyme bands could be identified in the species analyzed. In Pseustes sulphureus sulphureus and Clelia clelia plumbea three bands were detected at the LDH‐5 site, suggesting the existence of an electro‐phoretic variant of the A subunit. Additional isozymes restricted to regions of the eye were also observed in some Bothrops insularis and B. jararaca. A population study of Boa constrictor amarali, Philodryas patagoniensis, Xenodon merremii, Bothrops insularis, and B. jararaca failed to detect any LDH polymorphism.