bluuebunny/crossref_metadata_2025_split huggingface dataset:
Androgen receptor in the harderian glands of the golden hamster: Characterization and the effects of androgen deprivation, the pituitary, and gender
Authors: McBlain William A. , Hoffman Roger A. , Buzzell Gerald R. 
Published: June 2005

AbstractThe Harderian glands of the golden hamster were found, by a competitive binding assay using [3H]mibolerone as the ligand, to have a high affinity androgen receptor. In intact male hamsters, this receptor was present in both cytosolic and nuclear KCl‐extractable fractions. Castration or hypophysectomy led to 3‐ to 5‐fold increases in the concentrations of cytosolic receptor with decreased dissociation constants. Hypophysectomy with maintenance of prolactin levels (by removal of pituitaries and their implantation either in the sella turcica or under the kidney capsule) had no effect on androgen receptor binding, compared to hypophysectomy alone. Female hamsters had androgen receptor levels which were 2 to 4 times higher than those of intact males. Hypophysectomy led to elevated receptor binding in ovariectomized female hamsters and this rise was prevented by maintaining prolactin levels. Binding of [3H]mibolerone in male glands was effectively inhibited by 5α‐dihydrotestosterone, whereas the parent molecule, testosterone, required approximately a 10‐fold greater molar excess to achieve the same amount of inhibition. Estradiol and progesterone were relatively poor inhibitors of the observed binding of [3H]mibolerone, while dexamethasone was ineffective. Sucrose gradient studies indicated that the Harderian androgen receptor migrated to the 8S region, as expected for this receptor in molybdate‐containing gradients. These results indicate that the androgen receptor in the hamster Harderian gland is a 5α‐dihydrotestosterone receptor. © 1994 Wiley‐Liss, Inc.
Electrophoretic characterization of equine oviductal fluid
Authors: Willis P. , Sekhar K. N. C. , Brooks P. , Fayrer‐Hosken R. A. 
Published: June 2005

AbstractTo characterize further the events involved in fertilization and early embryonic development in the mare, effect of the estrous cycle on oviductal fluid proteins was investigated. Five mares had indwelling cannulas placed in their oviducts so that fluid could be collected throughout the estrous cycle. Daily fluid volumes were recorded and mares were monitored for signs of standing estrus. Oviductal fluid samples were pooled across mares according to stage of cycle (either estrus or nonestrus) for further analysis. Two‐dimensional polyacrylamide gel electrophoresis (PAGE) was used to determine proteins present in estrus‐associated and nonestrus‐associated equine oviductal fluid as compared to blood serum from the same mares. Oviductal fluid volumes increased significantly during estrus to an average of 3.94 ml/24 hr from 1.44 ml/24 hr during nonestrus. Total oviductal protein increased significantly from 24.6 mg/24 hr during nonestrus to 53.9 mg/24 hr during estrus. One‐dimensional PAGE demonstrated that the proteins in equine oviductal fluid were present throughout the cycle and also common to equine serum. Reducing conditions revealed one band at 106 kDa detected only in nonestrus‐associated oviductal fluid, while nonreducing conditions revealed bands at 48 and 25 kDa that were present in oviductal fluid in general. Two‐dimensional PAGE demonstrated three 50 kDa proteins that were detected only in estrus‐associated oviductal fluid and several 24 kDa proteins detected only in nonestrus‐associated oviductal fluid. Those proteins found only in estrus‐associated oviductal fluid may be vital to the fertilization process, while those found only in nonestrus‐associated oviductal fluid may be vital to early embryonic development. © 1994 Wiley‐Liss, Inc.
Comparison between the sulfated polysaccharides from larval and adult ascidians
Authors: Pavão Mauro S. G. , Lambert Charles C. , Lambert Gretchen , Mourão Paulo A. S. 
Published: June 2005

AbstractPreviously we reported the occurrence of novel sulfated polysaccharides in the tunic of adult ascidians (Mourão and Perlin [1987], Eur. J. Biochem., 166:431–436; Pavão et al. [1989a], J. Biol. Chem., 264:9972–9979). In the present study we compare the polysaccharides from larval and adult ascidians. They differ markedly in electrophoretic mobility and chemical composition. Thus, larvae of ascidians contain a complex sulfated polysaccharide composed of D‐glucose, L‐fucose, and L‐galactose, whereas the adult tunics have a single sulfated L‐galactan. This result may reflect changes in the metabolic pathways involved in the biosynthesis of these sulfated polysaccharides after metamorphosis of the ascidian. © 1994 Wiley‐Liss, Inc.
Embryonic expression pattern of amyloid protein precursor suggests a role in differentiation of specific subsets of neurons
Authors: Salbaum J. Michael , Ruddle Frank H. 
Published: June 2005

AbstractImmunohistochemical analysis revealed the temporal and spatial expression pattern of the amyloid protein precursor (APP) during the development of the mouse embryo. APP was first detected at day 9.5 of gestation in motor neurons of the hind brain and the spinal cord. APP proteins were also evident in cells of the floor plate, and in neurons of the cranial, dorsal root, and sympathetic ganglia shortly after their formation. Except for floor plate cells, APP expression was restricted to differentiated neurons. Comparison with the expression of microtubule‐associated protein 2 (MAP‐2), a marker for neurodifferentiation, showed that APP is expressed on a subset of differentiated neurons. APP can also serve as an early marker for the developing nuclei of the hind brain. The onset of APP expression in neurons appeared to be correlated with axonal outgrowth, whereas later expression of APP may be associated with functional specialization in the developing nervous system. © 1994 Wiley‐Liss, Inc.
Binding of starfish and sea cucumber sperm attractants to whole sperm and sperm fragments
Authors: Miller Richard L. , Crawford Dwight 
Published: June 2005

AbstractBinding of starfish and sea cucumber sperm attractants to whole, living spermatozoa and to separated, purified, sperm heads and tails was measured by assaying for loss of sperm attracting activity from solution. Starfish sperm attractant bound mainly to whole sperm or isolated sperm tails and much less, or not at all, to isolated sperm heads. Binding of starfish attractant to sea cucumber sperm or sperm fragments did not occur, nor did sea cucumber sperm attractant bind to starfish sperm or sperm fragments. However, sea cucumber attractant bound equivalently to separated sea cucumber sperm heads and tails. Starfish sperm attractant remained bound to whole sperm or isolated sperm tails if they were frozen‐thawed, but was released if the sperm or sperm fragments were heated. Starfish attractant did not bind to sperm that was previously killed by heat or freezing and thawing but did bind to formalin‐fixed, sea water‐washed sperm. Removal of the sperm membrane using Triton X‐100 eliminated the ability to bind sperm attractant. Although the ratio of the surface areas of tails to heads was approximately 1.5 to 1, up to 10 times more sperm attractant bound to starfish sperm tails than to heads. These results are similar to the binding pattern of the motility‐activating, egg jelly‐derived peptides speract (SAP‐I) and alloresact (SAP‐IIB) to sea urchin sperm heads and tails. They suggest that starfish and sea cucumber sperm attractants bind to sperm membranes in a manner similar to the sperm activating peptides of sea urchins. © 1994 Wiley‐Liss, Inc.
Structural analysis of photosystem I polypeptides using chemical crosslinking
Authors: Armbrust Trent S. , Odom William R. , Guikema James A. 
Published: June 2005

AbstractThylakoid membranes, obtained from leaves of 14 d soybean (Glycine max L. cv. Williams) plants, were treated with the chemical crosslinkers glutaraldehyde or 1‐ethyl‐3‐(3‐dimethylaminopropyl)‐carbodiimide (EDC) to investigate the structural organization of photosystem I. Polypeptides were resolved using lithium dodecyl sulfate polyacrylamide gel electrophoresis, and were identified by western blot analysis using a library of polyclonal antibodies specific for photosystem I subunits. An electrophoretic examination of crosslinked thylakoids revealed numerous crosslinked products, using either glutaraldehyde or EDC. However, only a few of these could be identified by western blot analysis using subunit‐specific polyclonal antibodies. Several glutaraldehyde dependent crosslinked species were identified. A single band was identified minimally composed of PsaC and PsaD, documenting the close interaction between these two subunits. The most interesting aspect of these studies was a crosslinked species composed of the PsaB subunit observed following EDC treatment of thylakoids. This is either an internally crosslinked species, which will provide structural information concerning the topology of the complex PsaB protein, a linkage with a polypeptide for which we do not yet have an immunological probe, or a masking of epitopes by the EDC linkage at critical locations in the peptide which is linked to PsaB. © 1994 Wiley‐Liss, Inc.
Comparative assessment of the polypeptide profiles from lateral and primary roots of Phaseolus vulgaris L
Authors: Westberg Jeffrey , Odom William R. , Guikema James A. 
Published: June 2005

AbstractIn Phaseolus vulgaris, primary roots show gravitational sensitivity soon after emerging from the seed. In contrast, lateral roots are agravitropic during early development, and become gravitropic after several cm growth. Primary and lateral root tissues were examined by polyacrylamide gel electrophoresis, coupled with western blotting techniques, to compare proteins which may contribute to the acquisition of gravitational sensitivity. Root tips and zones of cell elongation were compared for each root type, using immunological probes for calmodulin, α‐actin, α‐tubulin, and proteins of the plastid envelope. Lateral roots contained qualitatively less calmodulin, and showed a slightly different pattern of actin‐related epitope proteins, than did primary root tissues, suggesting that polypeptide differences may contribute to the gravitational sensitivity which these root types express. © 1994 Wiley‐Liss, Inc.
Insect gravitational biology: Ground‐based and shuttle flight experiments using the beetle Tribolium castaneum
Authors: Bennett R. L. , Abbott M. K. , Denell R. E. 
Published: June 2005

AbstractMany of the traditional experimental advantages of insects recommend their use in studies of gravitational and space biology. The fruit fly, Drosophila melanogaster, is an obvious choice for studies of the developmental significance of gravity vectors because of the unparalleled description of regulatory mechanisms controlling oogenesis and embryogenesis. However, we demonstrate that Drosophila could not survive the conditions mandated for particular flight opportunities on the Space Shuttle. With the exception of Drosophila, the red flour beetle, Tribolium castaneum, is the insect best characterized with respect to molecular embryology and most frequently utilized for past space flights. We show that Tribolium is dramatically more resistant to confinement in small sealed volumes. In preparation for flight experiments we characterize the course and timing of the onset of oogenesis in newly eclosed adult females. Finally, we present results from two shuttle flights which indicate that a number of aspects of the development and function of the female reproductive system are not demonstrably sensitive to microgravity. Available information supports the utility of this insect for future studies of gravitational biology. © 1994 Wiley‐Liss, Inc.
Development of the brine shrimp Artemia is accelerated during spaceflight
Authors: Spooner Brian S. , Metcalf Janet , DeBell Lynnette , Paulsen Avelina , Noren Winn , Guikema James A. 
Published: June 2005

AbstractDevelopmentally arrested brine shrimp cysts have been reactivated during orbital spaceflight on two different Space Shuttle missions (STS‐50 and STS‐54), and their subsequent development has been compared with that of simultaneously reactivated ground controls. Flight and control brine shrimp do not significantly differ with respect to hatching rates or larval morphology at the scanning and transmission EM levels. A small percentage of the flight larvae had defective nauplier eye development, but the observation was not statistically significant. However, in three different experiments on two different flights, involving a total of 232 larvae that developed in space, a highly significant difference in degree of flight to control development was found. By as early as 2.25 days after reactivation of development, spaceflight brine shrimp were accelerated, by a full instar, over ground control brine shrimp. Although developing more rapidly, flight shrimp grew as long as control shrimp at each developmental instar or stage. © 1994 Wiley‐Liss, Inc.
Eicosanoid synthesis by warm‐and cold‐acclimated American bullfrog (Rana catesbeiana) brain
Authors: Martinez Jeanelle M. , Chapunoff David , Romero Melissa A. , Herman Ceil A. 
Published: June 2005

AbstractPrevious studies in bullfrogs have demonstrated the presence of leukotriene (LT)C4 binding sites in the brain. However, synthesis of eicosanoids by brain tissue has not been examined. Because prostaglandin (PG) synthesis differs in warm‐ and cold‐acclimated bullfrog lung tissue, this study compared the synthesis of prostaglandins and leukotrienes in brains from warm‐(22°C) and cold‐acclimated (5°C) animals. Initial experiments determined that leukotriene and prostaglandin production rates were greatest during the initial 30 min time period. Therefore, tissues were incubated in Munsick's solution and gassed with 95% O2, 5% CO2 for 30 min. Media were analyzed by radioimmunoassay for LTC4, LTB4, PGE2, PGF2α, TXB2, and 6‐keto PGF1α. In warm‐acclimated bullfrog brains, production was as follows: LTC4 > PGE2 > 6‐keto PGF1α, thromboxane (TX)B2, LTB4, and PGF2α. Brain tissues from cold‐acclimated animals incubated at 22°C produced significantly greater quantities of PGE2 and 6‐keto PGF1α than did brains from warmacclimated animals. Stimulation of TXB2 levels was observed when the animal was stunned with a blow to the head prior to decapitation. Indomethacin, a cyclooxygenase inhibitor, decreased prostaglandin but not leukotriene synthesis. Epinephrine (4 × 10−8M), the amphibian sympathetic postganglionic neurotransmitter, stimulated leukotriene synthesis by brains from warm‐acclimated bullfrogs, and the effect was blocked with the 5‐lipoxygenase inhibitor MK‐886 (5 × 10−5M). These results clearly indicate that the bullfrog brain synthesized both leukotrienes and prostaglandins. Further studies are necessary to determine their function in the amphibian central nervous system. © 1994 Wiley‐Liss, Inc.
Culture of rat renal medullary tissue in media made hyperosmotic with NaCl and urea
Authors: Isabelle M. E. , Githens S. , Moses R. L. , Bartell C. K. 
Published: June 2005

AbstractDuring antidiuresis, the rat kidney maintains a variable and steep osmotic gradient from the cortex (300 mOsm) to the inner medulla (at least 2,600 mOsm). Therefore, cells in the renal medulla must be able to adapt to a variably hyperosmotic environment. We have examined the ability of tissue fragments taken from various points on the cortical‐medullary axis to survive and grow when cultured in media made hyperosmotic with urea and NaCl. Survival and growth were measured by the explants' ability to produce epithelial outgrowths. At osmotic concentrations of 1,100 and 1,200 mOsm, only explants from the inner medulla produced epithelial outgrowths. At 700 mOsm, all explants produced outgrowths but outgrowth size was a function of position on the cortical‐medullary axis, with inner medullary fragments producing the largest outgrowths. Growth was most rapid at all osmolalities when the Na+:urea ratio was 1:1. These results are consistent with the hypothesis that renal medullary cells are adapted to elevated concentrations of Na+ and urea. Both explants and epithelial outgrowths were examined using light and electron microscopy. Physical continuities between the epithelial outgrowths and collecting duct epithelium in the explants, as well as the ultrastructural characteristics of the outgrowths at 700 mOsm, indicated that the outgrowths may have originated from collecting duct epithelium. © 1994 Wiley‐Liss, Inc.
Establishment and maintenance of claw bilateral asymmetry in snapping shrimps
Authors: Young R. E. , Pearce J. , Govind C. K. 
Published: June 2005

AbstractThe paired asymmetric chelae, or claws, in snapping shrimps, Alpheus heterochelis, differ in form and function; the major, or snapper, claw is grossly enlarged, has a hammer and socket, and functions in agonistic displays, while the minor, or pincer, claw is small and slender and functions in burrowing and feeding. The paired claws are symmetrical and undifferentiated in the larval and early juvenile stages but differentiate on a random basis into a snapper and a pincer claw by the sixth juvenile stage. Removal of one of the paired claws in the third or fourth juvenile stage results in the intact claw developing into a snapper, suggesting that differential use initially determines claw type. However, claw bilateral asymmetry may be altered in adults as removal of the snapper claw causes transformation of the existing pincer into a snapper while a new pincer regenerates at the old snapper site. To test the hypothesis that inhibitory influences from the transforming pincer‐to‐snapper claw may limit the newly regenerating claw to a pincer type, we observed the effects of closer muscle tenotomy and nerve lesions in the intact transforming claw on the type of claw regenerated at the old snapper site. With mild tenotomy in which the tendon is cut at its attachment to the moveable dactyl but the closer muscle and its innervation is otherwise intact, a pincer claw regenerates similar to the control animals. However, with radical tenotomy in which the tendon is removed from the claw and the closer muscle and its innervation is severely disrupted, either a pincer or snapper claw regenerates. Lesioning of the large nerve 2 by itself or together with the small nerve 1 (but not nerve 1 by itself) in the intact transforming claw also permits regeneration of either a pincer or snapper claw at the old snapper site. Thus, neural influences from the transforming pincer‐to‐snapper claw restrict regeneration of the contralateral claw to a pincer type thereby ensuring bilateral asymmetry in adult shrimps. © 1994 Wiley‐Liss, Inc.
In vivo evidence that the premature death (p) mutation of Ambystoma mexicanum affects an early segregating subpopulation of neural crest cells
Authors: Graveson Ann C. , Armstrong John B. 
Published: June 2005

AbstractThe premature death (p) mutation of Ambystoma mexicanum causes a variety of abnormalities and rapid degeneration in homozygous embryos. We have previously determined that the differentiative ability of the chondrogenic neural crest is severely deficient in these embryos. In this study, we demonstrate that the axial specification of the defective neural crest cells is normal, since their major migration routes are the same as those of wild‐type cells from the same axial levels. In addition, we use a series of transplantations and extirpations to show that other neural crest cell populations are also affected by the mutation. The defects observed in p/p embryos, therefore, suggest a role for the neural crest in the morphogenesis of the gills in the establishment of a functional circulatory system, and perhaps in the proper development of other organ systems. We propose that the subset of neural crest cells which are affected by the mutation may represent an intermediate subpopulation produced during the segregation of the neural crest. © 1994 Wiley‐Liss, Inc.
The influence of male‐specific genes on female muscle fiber types: Studies on the sex‐reversed (Sxr) mouse
Authors: Stickland Neil C. , O'Shaughnessy Peter J. 
Published: June 2005

AbstractPrevious experiments on the effects of either male castration or injection of androgens have concluded that levels of androgens are responsible for different muscle fiber type proportions between the sexes. However, these conclusions are based on invasive techniques which may involve secondary factors. The sex‐reversed (Sxr) mouse is genetically female (X/X) but phenotypically male due to the presence of part of the short‐arm of the Y chromosome containing the testis determining gene (Tdy). Serum testosterone in this mouse is in the low normal range and therefore provides a model for investigating the possible control of muscle fiber types by male specific genetic factors.Ten males, ten females, and ten Sxr mice of approximately 60 days of age were used, together with ten males weight‐matched to the females. The animals were killed and biceps brachii and soleus muscles removed and prepared for routine muscle histochemistry. Body and muscle weights were similar in the males and Sxr mice and significantly greater than in the females and the weight‐matched males. Muscle fiber sizes in biceps brachii reflected the differences in muscle weights and there were no significant differences in fiber type proportions for this muscle. In the soleus muscle, the percentage of slow, oxidative (SO) fibers was higher in the female mice than in any other group. Furthermore, although the fast, oxidative, glycolytic (FOG) fibers were larger in the heavier animals, SO fibers were largest in the female mice.The results indicate that, although the size of FOG and fast, glycolytic (FG) fibers may be a result of work‐load hypertrophy related to body weight, the proportion and size of SO fibers in the soleus is directly influenced by genetic factors derived from the Y‐chromosome, probably Tdy. © 1994 Wiley‐Liss, Inc.
Directional light transmission in the pineal window of Atlantic salmon (Salmo salar L.) may be used for solar orientation
Authors: Nordtug Trond , Berg Ole Kristian , Melø Thor Bernt 
Published: June 2005

AbstractThe pineal window of adult Atlantic salmon (Salmo salar) (fork length 45–55 cm) is highly transparent, apart from a roof‐like (mean angle 120° ± 5°), bony structure formed by the pineal plates. On each side of the bony pineal plates there is a white lining which acts like an optical diffusor. The forward scattering of an incident narrow laser beam by the pineal plates was observed by an optical fibre and a diode array. The direction for maximum intensity of the scattered light below the pineal plates is refracted with respect to the incidence angle, and the half‐width of the scattered light intensity is 22°. Furthermore, the maximum transmittance of a light ray, with an incidence angle μ with respect to the pineal plates, depends upon μ according to a (1 + cosμ) function. Hence, each pineal plate of the laminar roof grossly receives light from the corresponding hemisphere and projects and assembles the rays on to the pineal organ at an angle of about 30° relative to the vertical plane along the body axis. In spite of the light scattering by the pineal window, a polarization factor of 0.60 was found at the level of the pineal organ for linearly polarized incident light.The hypothesis is proposed that these properties have ultimately evolved as a directional aid enabling the fish to orient by the directionality of the sunlight. © 1994 Wiley‐Liss, Inc.