bluuebunny/crossref_metadata_2025_split huggingface dataset:
Hemodynamics in the pink abalone, Haliotis corrugata (mollusca, gastropoda). I. Pressure relations and pressure gradients in intact animals
Authors: Bourne George B. , Redmond James R. 
Published: June 2005

AbstractAfter establishing basic anatomical relationships in the circulatory system of the pink abalone, Haliotis corrugata, blood‐pressure measurements were made in the ventricle, aorta, left epipodial artery, afferent ctenidial veins, efferent ctenidial veins, and the pericardial chamber with strain‐gauge manometers on unrestrained specimens at 15°C. All sites showed pulsatile pressures of low magnitude. Intraventricular pressure normally ranged from slightly above ambient during diastole to about 8 cm water at systole, and produced a mean pressure gradient of 5.5 cm water between the aorta and the efferent ctenidial veins. Pressure variations and pulse waves recorded from structures within the pericardium support a constant‐volume mechanism for cardiac filling. There is no clear evidence that body movement enhanced venous return.
Hemodynamics in the pink abalone, Haliotis corrugata (mollusca, gastropoda). II. Acute blood‐flow measurements and their relationship to blood pressure
Authors: Bourne George B. , Redmond James R. 
Published: June 2005

AbstractIn the pink abalone, Haliotis corrugata, pulsatile flow and pulsatile pressure were measured at 15°C by electromagnetic and Doppler ultrasonic flowmeters and strain gauge manometers. Flow was pulsatile in all areas of the arterial system investigated, i.e., the aorta, the cephalic arterial sinus and pedal arteries. Flow rates of approximately 2.9 ml/min were measured in the aorta of animals after surgical implantation of electromagnetic flowprobes. The events of the cardiac cycle are correlated with aortic blood flow. Simultaneous recording of pressure and flow suggested that the action of the aortic bulb maintained aortic flow during ventricular diastole.
Accumulation and degradation of three major yolk proteins in Drosophila melanogaster
Authors: Bownes M. , Hames B. D. 
Published: June 2005

AbstractIn contrast to previous findings, three major yolk proteins have been identified in the oocytes and eggs of Drosophila melanogaster. They are also present as major proteins in the haemolymph of mature females and in trace amounts in the haemolymph of young females; the male haemolymph lacked all three proteins. Female fat body contained the three proteins and, surprisingly, trace amounts were also present in the male fat body. The accumulation and degradation of the three yolk proteins by oocytes and embryos was asynchronous suggesting that independent controls may exist.
Immunofluorescent localization of acrosin in mammalian spermatozoa
Authors: Garner Duane L. , Easton Marlys P. 
Published: June 2005

AbstractAcrosin was detected by immunofluorescence in the spermatozoan acrosomes of artiodactyla (bull, ram and boar), perissodactyla (horse), carnivora (dog and cat), lagomorpha (rabbit) and primates (human) using anti‐bovine acrosin immunoglobulins. The results indicate that the acrosin molecules of several mammalian species possess antigenic similarities.
Changes in cyclic GMP levels during forelimb regeneration in adult notophthalmus viridescens
Authors: Liversage Richard A. , Rathbone Michel P. , McLaughlin Hooley M. G. 
Published: June 2005

AbstractCyclic 3′,5′‐guanosine monophosphate (cGMP) was measured at eight stages of forelimb regeneration in adult newts and compared with the cGMP levels of non‐regenerating control limbs. There was a significant increase in cGMP content during dedifferentiation followed by a sharp decrease to minimal levels at the cone stage. A second smaller increase in cGMP occurred between the cone stage and mid‐differentiation, followed by a decrease to relatively constant levels approaching control values as differentiation progressed. The changes in cGMP during dedifferentiation and during the period of highest cell proliferation indicate that cGMP may play a role in these processes. The smaller increases in cGMP levels during differentiation may reflect a reduced rate of cell division in the differentiating tissues.
A Mg++ dependent cortical reaction in the eggs of penaeid shrimp
Authors: Clark Wallis H. , Lynn John W. 
Published: June 2005

AbstractMature penaeid oocytes contain large cortical specializations (rods) in their cortex. These rods reside in membrane crypts and are isolated from the external environment by a thin investment coat which surrounds the oocyte. When oocytes contact seawater, at spawning, their cortical rods are expelled and form a striking investment layer which subsequently dissipates. During cortical rod dissipation a hatching membrane forms around the egg. Oocytes spawned into Mg++ free seawater do not exhibit cortical rod explusion. If oocytes spawned into Mg++ free seawater are returned to normal seawater cortical rod explusion proceeds, however the expelled rods do not dissipate.
Cytodifferentiation in the accessory glands of Tenebrio molitor. I. Ultrastructure of the tubular gland in the post‐ecdysial adult male
Authors: Gadzama Njidda M. , Happ Christine M. , Happ George M. 
Published: June 2005

AbstractThe tubular accessory reproductive glands of the male mealworm beetle consist of a secretory epithelium surrounded by a thin muscular sheath. Each columnar secretory cell is divisible into three zones: basal which is adjacent to the muscle layer and contains rough endoplasmic reticulum and Golgi, intermediate, which contains endoplasmic reticulum and Golgi zones in the immature gland and is filled with secretory vesicles in the mature gland, and apical. Maturation also involves proliferation and organization of the rough endoplasmic reticulum in the basal and intermediate zone. The process appears to be complete at four days after ecdysis. Parallels with other insect glands and with the mammalian prostate are striking.
The genetic control of the pituitary‐gonadal axis in the platyfish, Xiphophorus maculatus
Authors: Schreibman Martin P. , Kallman Klaus D. 
Published: June 2005

AbstractA sex‐linked gene controls the age at which the gonadotropic zone of the pituitary gland develops and becomes physiologically active. The alleles for early (Pe) and late(Pl) differentiation are linked to pigment genes that serve as genetic markers. Pe may be marked by Sp, Dr, Sr, Ir and + and Pl by Br and N. Ir females (PePe) matured between 10 to 15 weeks of age and Br (PePl) females between 16 to 20 weeks. Dr (PePe) females had ripe ovaries six to eight weeks earlier than N Dr (PePl) females (8 to 12 weeks versus 16 to 20 weeks). The average age of sexual maturation was 12.5 weeks for Ir Ir (PePe) males, 20 weeks for Ir Br (PePl) and 26.5 weeks for Br Br (PlPl) males. Dr Sr (PePe) males reached maturity at 13.5 weeks and N Sr (PePl) males at 27.5 weeks. The transformation of the anal fin into a gonopodium which is under androgenic control, takes longest in the late maturing fish (Ir Ir, 3.8 weeks; Ir Br, 4.8; Br Br, 6.5; Dr Sr, 4.2; N Sr, 6.4). Similarly, the rate of development of the gonadotropic zone and of the gonad is protracted in the late genotypes. Eventually, the gonadotropic zone of early and late maturing fish are indistinguishable. The Pl factor linked to N delays sexual maturity to a greater extent than the one linked to Br suggesting that not all Pl factors are identical and that important allelic interactions may exist. The growth rate of immature males and females is the same, however it declines sharply in males (but not females) at the time of sexual maturity. This leads to significant differences in adult size between male genotypes. Female genotypes do not exhibit size differences and eventually become larger than all males. The development of the gonadotropic zone precedes, and is essential for, complete gonadal maturation. In the absence of a functional gonadotropic zone, oocytes developed through the oil droplet stage and were surrounded by active follicle cells and a prominent zona pellucida. Spermatogenesis proceeded up to the spermatocyte stage and the cells lining the efferent ducts displayed a modicum of activity. Some of our data suggest that low levels of androgens are present in all males as early as five weeks of age prior to the development of gonadotrops. The genes regulating the development of the pituitary‐gonadal axis may be an important factor in explaining the evolution of poeciliid fish.
Embryotoxic effects of heterologous antisera against rat reichert's membrane
Authors: Leung Christopher C. K. 
Published: June 2005

AbstractParietal yolk‐sacs of rat embryos at the fifeenth day of gestation were obtained by microdissection. A Reichert's membrane (RM) preparation was isolated by treating the parietal yolk‐sacs with the chelating agent tetrasodium salt of ethylenediaminetetraacetic acid (EDTA) combined with mechanical shaking. Less than 1% of the membrane preparation was DNA and phosphorus contaminants. The membrane purity was also evaluated by electron microscopic examination. Rabbit Ig G directed against the RM preparation when injected ip into ninth day pregnant rats produced malformations, fetal growth retardation and resorption. Fluorescent‐labeled antibody localization studies demonstrated that the teratogenic antibodies localized in RM. It is postulated that RM antibodies induce teratogenesis by interfering with the function of RM.
Some effects of mating in female tsetse, Glossina austeni newst
Authors: Ejezie G. C. , Davey K. G. 
Published: June 2005

AbstractVirgin females of G. austeni were mated at carefully chosen physiological states to determine the effect of mating on ovulation, neurosecretion and blood meal size. The results suggest that ovulation and larviposition are controlled by neurosecretion, and that the release of neurosecretion requires both a mating stimulus and the presence of a mature egg in one of the ovarioles. The mating stimulus was also found to lead to an increase in blood meal size. Unmated female flies do not ovulate and their mature eggs eventually disintegrate. Virgin blood meal sizes remain relatively low.
Influence of the thyroid and adrenal glands on the growth of the intestine of the suckling rat, and on the development of intestinal alkaline phosphatase and disaccharidase activities
Authors: Yeh Kwo‐Yih , Moog Florence 
Published: June 2005

AbstractPrevious investigations have shown that cortisone or thyroxine can promote maturation of the intestinal epithelium in rats hypophysectomized at six days of age. This indication that either the thyroid or the adrenocortical hormone can act in the absence of the other has been pursued by study of intestinal maturation in rats deprived of the thyroid or adrenal glands during the suckling period. At 24 days of age, rats that have been thyroidectomized at six days retain the short villi and low mitotic index characteristic of neonatal life. Thyroxine elevates the mitotic index; neither thyroxine nor cortisone promote lengthening of the villi, but both cause some deepening of the crypts. Duodenal alkaline phosphatase and jejunal maltase remain at very low levels, but sucrase, which is absent at six days, does appear in the thyroidectomized pups at 24 days. Thyroxine raises phosphatase and maltae activity to the normal 24‐day level, but cortisone is only partly effective. Sucrase is raised above the normal maximum by cortisone but not by thyroxine. After adrenalectomy at 14 days, cortisone corrects deficiencies in villus height, crypt depth, and mitotic index, but thyroxine is without effect. Phosphatae, maltase, and sucrase activities rise only to subnormal levels in adrenalectomized pups. Thyroxine restores phosphatase activity to the control level, but is only partly successful in normalizing disaccharidase activities. Periodic acid‐Schiff stainability of the brush border is weak in specimens deprived of either thyroid or adrenals. Both thyroxine and cortisone restore normal intensity after thyroidectomy; after adrenalectomy only cortisone was able to restore normal stainability. Plasma corticosteroid concentration is elevated by thyroxine only if the hypophysis is present. These results demonstrate that the intestinal epithelium is able to respond to each hormone in the absence of the other.
The effect of ascorbic acid on growth and synthesis of matrix components by cultured chick embryo chondrocytes
Authors: Hajek Anthony S. , Solursh Michael 
Published: June 2005

AbstractFifty μg/ml ascorbic acid was found to accelerate the growth of logarithmically growing chick embryo sternal chondrocytes in cell culture. Differences in the number of cells between control and ascorbate‐treated cultures were apparent by the fourth day of treatment when a 58% increase in the number of cells and a 35% increase in protein per culture were observed in ascorbate‐treated cultures. Under these conditions, the cell size and protein content per cell was reduced in ascorbate‐treated cultures.Collagen synthesis, which was measured by the amount of collagenase‐sensitive counts released from 3H‐proline labeled protein, was increased by 116% over controls after 24 hours of ascorbate treatment. Observations with scanning and transmission electron microscopy are consistent with the idea that ascorbate has a much greater effect on collagen secretion and demonstrate an ascorbate‐mediated change in matrix morphology.35S incorporation into hyaluronidase‐sensitive or cetylpyridinium chloride precipitates was accelerated by 57% by 24 hours of ascorbate treatment whereas two, four and six days of treatment caused decreases in this parameter of 19%, 57% and 35%, respectively. This effect was dependent on cell density. 35S incorporation probably reflects synthesis of new glycosaminoglycan similar results were observed when either 35S or 14C‐glucose incorporation was monitored. An effect of ascorbate on both collagen and glycosaminoglycan synthesis is consistent with the possibility that collagen and glycosaminoglycan synthesis can be coregulated under some circumstances.
Molecular aspects of temperature acclimation in fish: Contributions of changes in enzyme activities and isozyme patterns to metabolic reorganization in the green sunfish
Authors: Shaklee James B. , Christiansen James A. , Sidell Bruce D. , Prosser C. Ladd , Whitt Gregory S. 
Published: June 2005

AbstractSpectrophotometric and electrophoretic techniques were used to monitor qualitative and quantitative aspects of changes in 12 enzymes from five different tissues of green sunfish after thermal acclimation. Changes in dissolved oxygen concentrations over the range 5–25 ppm had no significant effect on qualitative or quantitative aspects of enzyme distributions.In response to differences in environmental temperature, however, significant changes in the levels of activity of fructose‐biphosphate aldolase, pyruvate kinase, lactate dehydrogenase, malate dehydrogenase, succinate dehydrogenase, cytochrome oxidase, cytochrome c, and glucose‐6‐phosphate dehydrogenase were observed in one or more tissues. Enzymes in a single metabolic pathway (e.g., glycolysis) usually exhibited parallel changes in a given tissue. Enzymes in different pathways, on the other hand, frequently exhibited changes in opposite directions, one group of enzymes increased in the cold while the other group decreased, indicating that major metabolic reorganizations were occurring. The patterns of change among tissues were distinctly different, therefore changes observed in one tissue cannot readily be generalized to other tissues.No changes in isozyme patterns were seen for lactate dehydrogenase, creatine kinase, fructose‐biphosphate aldolase, malate dehydrogenase, glucosephosphate isomerase, phosphoglucomutase, glycerol‐3‐phosphate dehydrogenase, or alcohol dehydrogenase in any of the tissues examined. However, some changes in the isozyme patterns of esterases in both liver and eye tissue were observed. These observations indicate that major changes in isozyme repertories do not necessarily accompany the thermoacclimatory responses of all fishes.
Anhydrobiosis in nematodes: Metabolism during resumption of activity
Authors: Crowe John H. , Madin K. A. C. , Loomis Stephen H. 
Published: June 2005

AbstractChanges in chemical composition, water content, respiration, and ability to survive rapid dehydration in dry air were studied in nematodes, Aphelenchus avenae, recovering from anhydrobiosis, in water. Water content rises rapidly, from about 0.02 mg H2O/mg dry weight to 2.0 mg/mg after five minutes and 2.9 mg/mg after four hours. Glycogen increases from 5 μg/mg to about 25 μg/mg after one hour. Glycerol and trehalose fall from 45 μg/mg and 125 μg/mg respectively to undetectable levels and 70 μg/mg after four hours. Oxygen uptake rises from about 25 nl/mg/min after ten minutes to 450 nl/mg/min after 1.5 hours and then falls to about 150 nl/mg min after four hours. Lipid content declines from 124 μg/mg to 51 μg/mg after 24 hours. Correlations were observed between survival in dry air and glycerol, trehalose, and water contents.
Accumulation of glucocorticoids in regenerating areas of limbs of the newt, Notophthalmus viridescens
Authors: Bromley Stephen C 
Published: June 2005

AbstractEvidence is presented that regenerating portions of newt limbs preferentially accumulate 3H‐labelled exogeneous cortisol and corticosterone. The ability of such regions to accumulate glucocorticoids is maximal about seven days after amputation and is abolished by interrupting the spinal nerves innervating the limb. Either hypophysectomy or ablation of interrenal tissue is without marked effect. The accumulation effect is not shown by aldosterone, testosterone, glucose, cholesterol, or leucine but estradiol does accumulate to a some‐what lesser extent than do the glucocorticoids examined.
An early step in initiation of fertilization in Paramecium: Early micronuclear migration
Authors: Fujishima Masahiro , Hiwatashi K. 
Published: June 2005

AbstractMicronuclear behavior in the early stage of conjugation in P. caudatum was observed. In stationary phase, the micronucleus is in a concavity of the macronucleus, but within 30 minutes after the mating reaction occurs or the cells are transferred into KCl solution for chemical induction of conjugation, the micronucleus leaves the concavity and moves into the cytoplasm. This phenomenon, called “early micronuclear migration” (EMM), occurs in about 90% of the cells prior to formation of holdfast union. The proportion of cells undergoing EMM is the same as the proportion of conjugants. Micronuclear migration is delayed by treatment with 5 mM colchicine, suggesting a role for microtubules in the phenomenon.
Photoreceptor degeneration in the eyes of an amphisbaenian in response to constant light or constant darkness
Authors: Gundy G. Craig 
Published: June 2005

AbstractEye morphology and behavioral responses were studied in Bipes biporus (Cope) exposed to normal photoperiods, constant light, and constant darkness. Control animals had retinas with a reduced number of outer segments relative to the typical vertebrate retina. In addition, many of these outer segments were poorly formed, suggesting a capability for light detection but not for image formation. Constant light led to detached retinas and eventual degeneration of outer segments. Earliest signs of detachment appeared in younger animals, but no subsequent age differences were found. Constant dark‐induced changes were similar to light‐induced changes except that dark‐induced changes were not so severe, did not depend on age, and included loss of pigment from cells in the pigmented epithelium. Retinal damage in constant dark animals suggests that free‐living Bipes biporus are occasionally exposed to light. Dark‐seeking behavior of normal animals diminishes after exposure to constant light.
Tail (end) bud contributions to the posterior region of the chick embryo
Authors: Schoenwolf Gary C. 
Published: June 2005

AbstractChick tail buds labeled with tritiated thymidine were transplanted homotopically to unlabeled embryos to determine the specific body levels and structures formed by tail buds. In addition, labeling patterns of posterior structures were studied in normal embryos labeled for progressively longer time periods.Tail buds contributed labeled cells primarily to tail neural tube, somites, mesenchyme, and caudal arteries, but not to tail notochord, skin ectoderm, hindgut, or tail gut. Labeled somites were often located three to four somite levels anterior to labeled portions of neural tubes. In labeled normal embryos central notochordal cells were labeled only occasionally. This labeling pattern extended posteriorly into a region designated as prospective notochord, which merged posteriorly with the tail bud. The tail bud labeled uniformly and contained about the same density of labeled cells as the segmental plates, indicating that proliferation was not excessive in the former.Defects in operated embryos occurred primarily in the neural tube, somites, and notochord. The tail portion of the notochord, presumably formed from the prospective notochordal region, was never isolated from the trunk portion. The tail portion of the neural tube rarely seemed isolated from the trunk portion. Large, unpaired midline somites frequently developed. They appeared to form only when a space was available in which paired segmental plates could approach the midline and fuse.
Tensiometric studies of cytokinesis in cleaving sand dollar eggs
Authors: Rappaport R. 
Published: June 2005

AbstractTensions exerted by cleavage furrows of Echinarachnius parma were measured by means of calibrated, flexible glass needles. The tensions exerted by the first and second furrows in isometric contraction were, respectively, 1.58 × 10−3 dyne (S.D. 0.41 × 10−3 dyne) and 1.43 × 10−3 dyne (S.D. 0.44 × 1.0−3 dyne). The difference between the two means is not significant. The tensions exerted by the same cleavage furrow at two different lengths, of which the shorter was about 66% the length of the longer, were not significantly different. When the progress of a second cleavage furrow was mechanically blocked, it continued to exert maximum tension up to 9 minutes after its companion blastomere, which served as a time control, completed cleavage.
Photoperiodic control of antler cycles in deer. IV. Effects of constant light:dark ratios on circannual rhythms
Authors: Goss Richard J. 
Published: June 2005

AbstractYearling sika deer, when exposed to constant unequal photoperiods since the autumnal equinox, replace their antlers the next spring and at irregular intervals thereafter. On equatorial light cycles (12L: 12D) they retain their original antlers indefinitely. The changeover occurs between constant day lengths of 12 3/4 and 13 hours. Since yearlings held on 6L:6D:6L:6D are able to replace their antlers on schedule, the failure to do so on 12L:12D is not due to light:dark parity, but to the 12‐hour durations of the days and/or nights.