bluuebunny/crossref_metadata_2025_split huggingface dataset:
Dimensions of control of cortical patterns in Euplotes: The role of pre‐existing structure, the clonal life cycle, and the genotype
Authors: Frankel Joseph 
Published: June 2005

AbstractWithin each of three investigated strains of Euplotes minuta (autogamous — A23; non‐autogamous — K7, VF17) variation was observed in the number of ciliary rows commonly manifested. Subcloning of two of these strains (A23, K7) revealed a strong tendency toward vegetative perpetuation of the preexisting row number; differences within genetically homogeneous material could persist over 200 fissions of serial propagation. However, initially different subclones tended gradually to converge toward a common distribution of row number. The rate of convergence depended on the strain and on the degree of senility.Non‐autogamous strains of E. minuta became senile at a clonal age of 500 to 700 fissions. Senility was manifested by reduced fission rates and by low survival after conjugation. Senile lines showed a reduced average ciliary row number, an increased variation in the row numbers commonly found, and a reduced fidelity in the vegetative propagation of preexisting row number. Initiation of new life cycles by conjugation reversed all of these effects.Young (non‐senile) clones displayed a characteristic range of ciliary row numbers, which remained the same following successive initiations of new clonal life cycles. This strain‐specific “stability range” was eight to nine rows for non‐autogamous strains (K7, VF17, and progeny of crosses between them) and nine to ten rows for the autogamous stock A23. The appearance of progeny lines with substantial numbers of ten‐rowed cells following a backcross of the A23 X VF17 F1 to the A23 parent (Heckmann and Frankel, '68) could therefore only have been due to genie contributions from the A23 parent. Reanalysis of the earlier data combined with results of the present study strongly suggest that the difference in stability range between the autogamous and non‐autogamous strains has a polygenic basis.
Growth inhibition in Rana pipiens due to sperm irradiation with ultraviolet rays
Authors: Pogany Gilbert C. 
Published: June 2005

AbstractWhen sperm are irradiated for periods varying from 5 to 120 seconds at 31 ergs/mm2, then allowed to fertilize untreated eggs, the ensuing embryos display distinct growth inhibition. The degree of growth inhibition is not proportional to the exposure; this is indicated by the condition observed in the five second embryos where growth is most retarded and abnormal. Cells in the irradiated embryos are shown to be smaller than the control. A possible mechanism for this reduced cell size is proposed based on the theory that chromosomes replicate in some linear fashion. It is also proposed that the abnormalities found in embryos subjected for five seconds be used to detect small radiation damages in other organisms.
Progressive alteration in the pattern of nucleic acid metabolism in the newt iris in cultivation
Authors: Jauker Fritz , Yamada Tuneo 
Published: June 2005

AbstractThe dorsal iris of the adult newt (Notophthalmus viridescens) was cultured in vitro for periods up to 12 days and then exposed to [3H] uridine. Labeled RNA extracted from the tissue was studied on a sucrose density gradient. The profiles indicate that incorporation into ribosomal RNA's is progressively increased during the first four days and progressively decreased during the following days. Incorporation into the precursor of ribosomal RNA is also progressively decreased in the later phase. Compared with ribosomal RNA's and their precursor, an RNA fraction with an S value higher than 40 is less affected. A study of incorporation of [3H] thymidine into the trichloroacetic acid‐insoluble fraction of the same tissue cultured in vitro showed a wave of incorporation beginning on day 4 and persisting to the end of the culture period. The data were compared with data obtained for the same tissue left in situ after lentectomy, which depigments and forms a lens.
Pressure and air flow during distress calls of the starling, Sturnus vulgaris (Aves;Passeriformes)
Authors: Gaunt Abbot S. , Stein Robert Carrington , Gaunt Sandra L. L. 
Published: June 2005

AbstractPresent hypotheses for the operation of the syringeal mechanism can be reduced to two models differing in whether closure of the syringeal bore is attributed to a pressure differential on either side of the vibrating membrane or to contraction of the syringeal musculature. Paucity of data, especially for songbirds, concerning the behavior of ventilated air during calling hinders application of either of the models to specific portions of the repertoire of any bird.Internal and tracheal pressures and air flow are recorded during distress
calls of the starling. Air sac pressures soar, often to more than 20 cm H20 ( × 40
normal respiratory amplitudes), while tracheal pressures are the same or lower
than during respiration. A distress call lasts twice as long as a normal exhala
tion, but flow is reduced and tidal volume increases only slightly. Seemingly,
the syringeal valve can regulate flow across a large, sustained pressure
differential. The inability of birds to vocalize when the interclavicular air sac
is ruptured is more easily explained by an alteration of flow to bypass a closed,
pressure independent valve than a necessity for a high pressure surrounding
the syrinx during vocalization. These studies suggest that reduction of the
syringeal lumen in songbirds is at least partially dependent on active con‐
striction rather than a passive flutter valve. The possible nature and selective
implications of such a mechanism are discussed.
Hamster sperm hyaluronidase. II. Its release from sperm in vitro in relation to the degenerative and normal acrosome reaction
Authors: Talbot Prudence , Franklin Luther E. 
Published: June 2005

AbstractHamster sperm incubated in vitro were used to determine: (1) when hyaluronidase is released from sperm undergoing acrosome detachment, i.e., either a degenerative or normal acrosome reaction, and (2) what ultrastructural changes occur in the acrosomes of living sperm during hyaluronidase release. Sperm were incubated up to 4 hours in normal saline, Ham's F‐10, or heat pretreated blood serum. At hourly intervals, the percentages of live (motile) and acrosome reacted sperm were counted, and the supernatant from each sperm sample was assayed for hyaluronidase activity. In normal saline, sperm died during the incubation period, underwent a degenerative acrosome reaction, and gradually released hyaluronidase. In Ham's F‐10, sperm lived throughout the incubation period, did not undergo acrosome detachment, and did not release detectable amounts of hyaluronidase. In heat pretreated blood serum, sperm death did not occur during the incubation period, a surge of hyaluronidase release was complete by 1 hour of incubation, and additional hyaluronidase activity was not detected in the incubation medium between 3 and 4 hours when the normal acrosome reaction was observed. The fine structure of the acrosome was unaltered immediately after the release of hyaluronidase in serum. It was concluded that more than 50% of the mechanically extractable hamster sperm hyaluronidase was released by a factor present in serum and that this release occurred prior to and independently of the normal acrosome reaction. The partial release of hyaluronidase in serum prior to the occurrence of a normal acrosome reaction may indicate that this enzyme has a bifunctional role in reproduction.
Oxygen consumption and lipid content in red and white muscles of antarctic fishes
Authors: Lin Yuan , Dobbs Gary H. , Devries Arthur L. 
Published: June 2005

AbstractAntarctic nototheniid fishes have red muscle which is restricted to the pectoral girdle region of the body. The muscle masses articulate the pectoral fins whose movement propels the fish during sustained low speed cruising. Both the rate of oxygen consumption and lipid content are higher in the red muscle masses than in white muscle. Electron microscope observations reveal large numbers of lipid droplets and mitochondria arranged in close association with one another. These findings support the hypothesis that red muscle is used for long, sustained swimming motion, and that lipid, rather than glycogen, is the main energy source for this activity.
The role of disulfide reduction in chromatin release from equine sperm
Authors: Wagner Thomas E. , Mann David R. , Vincent Roger C. 
Published: June 2005

AbstractThe induced expulsion of a condensed chromosomal strand from equine sperm head pieces by the combined action of guanidine HCl (0.35M) and β‐mercaptoethanol (5 × 10−3M) is documented by scanning electron microscopy. The circular dichroism spectrum of a disordered gel state of this expelled sperm chromatin is shown and suggests that the DNA component of this chromosomal material may be in the compact ψ‐DNA state, The possible role of ‐S‐S‐reductive breakdown in the sperm chromatin expulsion mechanism during fertilization is discussed.
A function for neurons (DUM) neurosecretory on skeletal muscle of insects
Authors: Hoyle Graham 
Published: June 2005

AbstractThe action of dorsal unpaired median (DUM) neurons of the locust Schistocerca gregaria and the grasshopper Romalea microptera was examined on the intrinsic rhythmic contractions that occur in their jumping muscles. The DUM neuron directly innervating the muscles, DUMETi, causes from partial to complete inhibition of the rhythm outlasting the stimulation by up to several minutes. The extent of inhibition, its time of onset and its duration, are proportional to the number and frequency of impulses. Other DUM neurons either exert a weaker, delayed effect, or none at all.
Inhibition of melanosome transformation in embryonic chick pigment retina cultured in vitro
Authors: Takeuchi Yoshiko K. , Takeuchi Ikuo K. , Kajishima Takao 
Published: June 2005

AbstractWhen the retinal pigment epithelial cells of the chick embryo are transferred to monolayer cultures, they lose their phenotypic trait — melanin granules — after a few days. Within the first 24 hours almost all of the melanosomes and premelanosomes are transformed into the degradative structures of the dense bodies or the melanosome complexes. Then, within a few days, these structures disappear completely from the cytoplasm. Actinomycin D, added to the culture medium during the first four hours, almost completely prevents the transformation of melanosomes and premelanosomes. The inhibition of cell proliferation, caused by the addition of colcemid, does not prevent the transformation, though the time of initiation of transformation is delayed considerably. The mechanisms of the transformation of pigment granules are discussed.
Optimal temperatures for inner‐ear performance in gekkonoid lizards
Authors: Werner Yehudah L. 
Published: June 2005

AbstractTemperature effects on the cochlear alternating potentials are described in lizards of the Eublepharidae (4 spp. and subspp.), Diplodactylinae (2 spp.), Gekkoninae (7 spp. and subspp.) and Sphaerodactylidae (1 sp.). Pure tones (50–15,000 Hz) were applied to the anaesthetized gecko's external ear. Sound intensity needed for a standard response was plotted (db versus frequency). A total of 249 such sensitivity functions were obtained from 50 animals, at temperatures of 15–40°.For each species, an optimal sensitivity function is definable by its extreme sensitivity and relative smoothness. This is obtained throughout a specific optimal temperature range. At lower temperatures, the function is less sensitive and its best sensitivity is at a lower frequency. The specific optimal cochlear temperature range resembles the specific ecological temperature preferendum where known. Both are broader in gekkonoid than in iguanid lizards.The temperature effects on the sensitivity function occur even with aerial or mechanical stimulation at the oval window after middle ear extirpation. Hence they arise in the inner ear. Their magnitude (db/°C) is half that known from auditory nerve potentials.When accurate auditory data are desired, the specific optimal temperature and its possible seasonal variation require consideration. This increases the need for proper identification of subjects by name and origin, and for monitoring experimental thermal parameters, including pre‐experimental acclimation.
Larval and adult abdominal defects resulting from microcautery of blastoderm staged Drosophila embryos
Authors: Bownes Mary 
Published: June 2005

AbstractDrosophila embryos were damaged by microcautery at the cellular blastoderm stage at the sites of presumptive histoblasts, identified from fate maps. The resulting adults were analyzed for abnormal abdominal structures in one series, and in two further series the pupal cases of the defective adults which hatched were also checked for irregularities in segmentation of the larva, both dorsally and ventrally. The relationships between the larval segmentation and adult pattern are described. A sample of pupal cases of morphologically normal flies hatching from microcautery were checked and showed that regulation only rarely occurred, i.e., abnormal larvae sometimes produced normal adults.Both tergite and sternite defects occurred, and duplications of parts of these structures were observed in both cases. In general, abnormal fusions, missing hemi‐segments, and partial deletions were associated with larval defects and were therefore probably the result of damage to larval cells, or both larval cells and histoblasts. Duplications and partial segment deficiencies also resulted from apparantly normal pupal cases and were therefore probably the result of directly damaging the presumptive histoblast cells of the blastoderm. It is suggested that the various nests of histoblasts in each segment act as one morphogenetic field, with larval cells within the field.
Serum thyroxine concentrations in larval and metamorphosing anadromous sea lamprey, Petromyzon marinus L.
Authors: Wright Glenda M. , Youson John H. 
Published: June 2005

AbstractThyroxine (T4) concentrations in samples of fresh sera taken from fed and unfed larval (ammocoetes) and metamorphosing anadromous sea lamprey (Petromyzon marinus) were measured by means of radioimmunoassay. T4 levels in unfed ammocoetes after a 1‐month period were not significantly different from those of the fed ammocoetes. Nutritional state of ammocoetes therefore does not seem to affect their serum T4 levels. Serum T4 concentrations decreased abruptly at the onset of metamorphosis and declined to levels observed in spawning adults (Leloup and Hardy, '76; Packard et al., '76) by the middle (stage 3) of metamorphosis. No significant change in serum T4 levels occurred between stage 3 to the end of metamorphosis. The possible significance of the decline in serum T4 levels to the metamorphic event in lamprey is discussed.
The effects of temperature and season of collection on the onset and duration of diapause in embryos of the annual fish Nothobranchius guentheri
Authors: Markofsky Jules , Matias Jonathan R. 
Published: June 2005

AbstractAnnual fish are found in temporary bodies of water in habitats of alternating rainy and dry seasons. The populations survive the dry seasons in the form of embryos encased in the bottom mud. Several genera of annual fish have been reported to exhibit diapause (developmental arrest) at three specific stages of development and it has been proposed that through this adaptation the populations are able to survive the variable durations of the dry seasons. The effects of incubation and spawning temperatures, and season of collection on the onset and duration of diapause in laboratory populations of the annual fish, Nothobranchius guentheri, were studied. At low incubation and spawning temperatures there was a prolongation of Diapause I and Diapause II. In addition, fish spawned at 25°C during the short days of winter produced embryos that entered a prolonged duration of Diapause II, whereas embryos produced during the long days of summer bypassed Diapause II.
Histochemical study of the amphibian digestive tract during normal and thyroxine‐induced metamorphosis. I. Alkaline phosphatase
Authors: Kaltenbach Jane C. , Lipson Marcia J. , Wang Claire H. K. 
Published: June 2005

AbstractHistochemical patterns of alkaline phosphatase activity were demonstrated in specific regions of the digestive tube in a series of growing and metamorphosing larvae and frogs of Rana pipiens. In growing larvae activity in the mucosal epithelium was intense and sharply localized in the striated border of the duodenum posterior to the bile duct and of the mid‐small intestine. No activity was found in the epithelial lining of the esophagus, stomach (or its glands), duodenum anterior to the bile duct, end of small intestine, or large intestine. Connective tissue and blood vessels throughout the length of the digestive tract displayed moderate activity. As remodeling of the gut began in metamorphosing larvae, the high phosphatase activity in the striated border decreased sharply, but activity in the connective tissue of the entire digestive tract increased substantially. As metamorphosis neared completion and a new mucosal epithelium developed, activity became strong in the striated border throughout the small intestine, including the region anterior to the bile duct and the end‐small intestine. In adult well‐fed frogs activity remained in this location, although in unfed frogs kept in the cold it diminished in the striated border and became prominent in subepithelial blood vessels. Enzyme activity was not detected in connective tissue (excepting random blood vessels) in any region of the frog digestive tract. These histochemical observations represent an overview of the distribution of alkaline phosphatase activity along the length of the digestive tract during larval and adult stages of a single anuran species.
On the buoyancy of the pearly Nautilus
Authors: Ward Peter , Martin Arthur W. 
Published: June 2005

AbstractFourteen freshly captured Nautilus macromphalus were weighed in seawater, and all were found to be negatively buoyant (heavier than seawater), with a mean weight of 1.76 g. Maximum rates of cameral liquid removal from chambers artificially filled with seawater were 1.0 ml/chamber/day at the surface. Specimens made artificially buoyant by the removal of cameral fluid, and maintained at 60 m or less, were unable to regain normal, slightly negative buoyancy through admission of new liquid into the emptied chambers via the siphuncle. Specimens maintained at depths of greater than 150 m all showed new cameral liquid in the previously emptied chambers. Because of the relatively slow rate of cameral liquid removal from the chambers, and seeming inability of Nautilu to place cameral liquid into emptied chambers in shallow water, we conclude that the phragnocone‐cameral liquid system is utilized for long term buoyancy adjustments rather than short term changes which might aid vertical ascent or descent.
Actin in mammalian sperm heads
Authors: Clarke G. N. , Yanagimachi R. 
Published: June 2005

AbstractAn actin‐like substance has been detected in the post‐acrosomal region of mammalian spermatozoa by indirect immunofluorescence. The antigen was localized using an anti‐actin antiserum from a patient with active chronic hepatitis. The actin‐like contractile proteins may be important in sperm function and sperm‐egg interactions during fertilization.
A gene necessary for late sperm function in Drosophila melanogaster
Authors: Geer B. W. , Bowman J. T. , Tyl B. T. 
Published: June 2005

AbstractA male‐sterile mutant, ms(1)7, of Drosophila melanogaster is defective in post‐ejaculatory sperm function. The mutant gene is located at one of at least five male fertility loci in 18F through section 20 of the polytene X‐chromosome. It is proposed that the ms(1)7 + gene product modifies a component of the sperm head. A nearby gene may be functionally related to ms(1)7+.
Limbless: A new genetic mutant in the chick
Authors: Prahlad K. V. , Skala Gerald , Jones Dean G. , Briles W. E. 
Published: June 2005

AbstractA mutation in the chicken resulting in total amelia is described. Genetic analysis indicates that the limbless condition is due to an autosomal recessive gene. In the limbless embryos the apical ectodermal ridge is lacking. However both the pectoral and pelvic girdles as well as the respiratory and excretory systems are normal. In the affected embryos usually the upper beak is shorter than the lower beak.
Calcium transport in crayfish gastrolith disc: Morphology of gastrolith disc and ultrahistochemical demonstration of calcium
Authors: Ueno Masaki 
Published: June 2005

AbstractAfter induction of premolt conditions in crayfish by injection of the molting hormone (β‐ecdysone), gastrolith disc tissue was examined electron‐microscopically. The following four types of epithelial cells were morphologically distinguished, synchronized with the stage of gastrolith growth. Type 1 cells, containing abundant mitochondria with microtubules extending from apical to basal side, are abundant during the intermolt period. Type 2 cells, highly vacuolated and containing hypertrophied mitochondria, are involuting and abundant during the period of gastrolith formation. Type 3 cells, having fine microvilli at the apical portion, begin to appear at the large gastrolith period. Type 4 cells, containing many irregular vesicles at the apical portion with mitochondria present in basal infoldings, are seen when the gastrolith formation is completed.These observations led to the assumption that the four types of cells represent the whole life cycle of an epithelial cell, starting from type 3 through type 4, type 1, and ending at type 2 involuting cells.From ultrahistochemical demonstration of calcium, the presence of calcium was nearly restricted to the hypertrophied mitochondria of type 2 cells, which eventually slough off to the gastric lumen.These findings suggest a unique calcium transport system: The hypertrophied mitochondria accumulate a large amount of calcium and supply calcium to the gastrolith.
Penetration of zona‐free hamster eggs in vitro by goat spermatozoa preincubated in the reproductive tract isolated from a maturing gilt
Authors: Kim C. I. , Niwa K. , Imai H. , Iritani A. 
Published: June 2005

AbstractWhen goat spermatozoa were preincubated for 5‐5.5 hr in the isolated uterus and oviduct from a maturing gilt, they developed the ability to penetrate zona‐free hamster eggs in vitro. Overall penetration rates were 17% and 0%, respectively, 1 hr after insemination, and these increased to 59% and 54% 2 hr later. The penetration rates were not improved by incubation longer than 2 hr after insemination up to 5 hr. Goat spermatozoa preincubated for 5 hr in a m‐KRB solution with or without goat serum penetrated zona‐free hamster eggs with difficulty. The results suggest that a functional change in the ability of goat spermatozoa to penetrate zona‐free hamster eggs may occur in the reproductive tract of different species.
Relationship between gill Na+,K+‐activated ATPase activity and osmotic stress in the plecopteran nymph, Paragnetina media
Authors: Kapoor N. N. 
Published: June 2005

AbstractA relationship between osmotic stress and gill Na+,K+‐activated ATPase was observed in plecopteran nymphs acclimated to diluted creek water and a hypertonic medium. An increase of 84% in diluted creek water is presumably related to an active uptake of sodium ions from the hypotonic medium. Whereas a 21% decrease in the enzyme activity may be related to the morphological changes in the specialized cells in the gills. The Na+, K+‐activated ATPase activity was also compared with the Malpighian tubules and the rectum. The highest ATPase activity of 32.6 ± 2 μmoles Pi mg protein−1 30 min−1 was observed in the Malpighian tubules. The activity in the gills (19 ± 1.2 μmoles Pi mg−1 30 min−1) was slightly lower than the rectum. Since the ATPase activity in the gills is quite high, the gills can be considered to play an active role in hyperosmotic regulation in plecopteran nymphs.