bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effects of dehydroepiandrosterone on obesity and glucose‐6‐phosphate dehydrogenase activity in the lethal yellow mouse (strain 129/Sv ‐ Ay/Aw)
Authors: Granholm Nels H. , Staber Lisa D. , Wilkin Peter J. 
Published: June 2005

AbstractWe investigated the anti‐obesity effects of the adrenal androgen, dehydroepiandrosterone (DHEA), on genetically predisposed obese lethal yellow mice (AY/AW). Secondly, we tested the hypothesis that DHEA promotes its anti‐obesity effects by decreasing the activity of glucose‐6‐phosphate dehydrogenase (G6PHD). We subjected four genotype‐sex combinations of yellow and agouti (control) mice to four dietary treatments and determined weight changes, food consumption, and G6PDH activity. Although G6PDH activities of yellow mice were considerably decreased in the 0.4% DHEA treatment group, they were elevated in the 0.0 and 0.1% DHEA treatment groups. In contrast, G6PDH activities of DHEA‐treated control agouti mice remained relatively constant. These studies confirm that DHEA prevents the Ay gene from promoting excess fat deposition via some mechanism(s) other than reduced dietary intake. However, the overall absence of agreement between weight change (gain or loss) and G6PDH activity suggests that the anti‐obesity activity of DHEA is not mediated via G6PDH. Since yellow obese (Ay/Aw) mice were found to be more susceptible to DHEA's effects than their agouti (Aw/Aw) littermates, Ay appears to induce an altered metabolism in Ay/Aw mice which is more susceptible to the effects of DHEA than the normal metabolism of Aw/Aw mice.
Ultrastructural evidence of calcium uptake by chloride cells in the gills of goldfish, Carassius auratus
Authors: Ishihara Akiko , Mugiya Yasuo 
Published: June 2005

AbstractCalcium uptake by the gills in goldfish (Carassius auratus) was observed by electron microscopy using an oxalate‐based method which specifically induced electron‐opaque precipitates in association with chloride cells in the primary epithelium. EDTA treatment and x‐ray microanalysis substantiated that these precipitates are a calcium salt. They were never found in deionized‐water‐adapted fish. Oxalate‐induced calcium precipitates, varying from 0.04 to 0.2 μl in diameter, occurred in the apical crypts of chloride cells and in large vacuole‐like structures in the lateral and basolateral regions of the cells. The crypts where the precipitates arose scatteringly had the morphological characteristics similar to the normal morphology of apical crypts: they were 2 to 4 μl in diameter and lined with darker and homogeneous cytoplasm with microridges. The vacuole‐like structures containing numerous calcium precipitates were somewhat irregular in contour and had a diameter of about 3 μl. They appeared to contact a densely distributed tubular system, but their limiting membrane was uncertain in the present resolution. The precipitates were concentrated in the central region of the structures. These results suggest that branchial calcium uptake is closely associated with chloride cells in goldfish.
Control of red cell volume and pH in trout: Effects of isoproterenol, transport inhibitors, and extracellular pH in bicarbonate/carbon dioxide‐buffered media
Authors: Nikinmaa Mikko , Steffensen John F. , Tufts Bruce L. , Randall David J. 
Published: June 2005

AbstractThe effects of extracellular pH and beta‐adrenergic stimula‐tion on the volume and pH of rainbow. trout red cells were studied in HCO3−/ CO2 butfered media. A decrease in extracellular pH caused an increase in red cell volume and a decrease in intracellular pH. The pH‐induced changes in cell volume were inhibited by 4,4′‐Diisothiocyanostilbene‐2,2′‐Disulfonic acid, (DIDS), an inhibitor of the anion exchange pathway, but not by amiloride, an inhibitor of Na+/H+ exchange, indicating that these volume changes are mainly associated with movements of chloride across the red cell membrane, and that the Na+/H+ exchanger is not activated by changes in intracellular pH alone. The adrenergic drug, isoproterenol, promoted cell swelling and proton extrusion even in the presence of 10 mM HCO3−, showing that the adrenergic response plays a significant role in the control of cytoplasmic pH. These responses were enhanced by a decrease in extracellular pH, showing that the adrenergic response is of benefit to stressed animals. DIDS markedly enhanced the effect of isoproterenol on the pHi, but abolished the increase in red cell volume. The effects of furosemide were similar to those of DIDS, suggesting that these transport inhibitors have a similar mode of action. Amiloride, on the other hand, inhibited both the volume and the pH changes associated with adrenergic stimulation. These observations support the double Na+/H+ and HCO3−/CI− exchange model of adrenergic swelling in fish red cells.
The oocyte of a new world marsupial, Monodelphis domestica: Structure, formation, and function of the enveloping mucoid layer
Authors: Phillips David M. , Fadem Barbara H. 
Published: June 2005

AbstractOvulated oocytes of the gray short‐tailed opossum Monodelphis domestica are surrounded by a thin zona pellucida and are devoid of a cumulus oophorus. In the ampulla of the oviduct, oocytes acquire a thick mucoid layer composed of concentrically arranged fibrillar material. Exocytosis by the secretory cells of the oviductal epithelium occurs in the region of the oviduct adjacent to the egg. This suggests that the oocyte‐zona‐mucus layer complex may influence the oviductal epithelium to secrete. During secretion, fibrillar contents of the secretion granules appear to be transformed into membranous material which presumably becomes fibrillar again as it is incorporated into the forming mucoid layer. Spermatozoa (which are known to pair in the cauda epididymis) are found in pairs and with intact acrosomes in the mucoid layer of fertilized eggs. This suggests that spermatozoa of Mondelphis remain paired until they reach the zona pellucida and that the acrosome functions in zona binding and/or penetration.
Genetic controls over melanocyte differentiation: Interaction of agouti‐locus and albino‐locus genetic defects
Authors: Lamoreux M. Lynn , Pendergast Phil 
Published: June 2005

AbstractTyrosinase activities and dopachrome conversion activity were evaluated in extracts made from skins of 6‐day‐old mice that were mutant at the agouti and albino loci. Dopa oxidase (DO) activity of tyrosinase in fully pigmented (C/C) mice is reduced in extracts made from skins of yellow 6‐day‐old mice as compared to those of black mice. Dopachrome conversion (DC) activity is absent from skin extracts of normal yellow mice and is present in normal black mice. DC activity is a characteristic of a separate enzyme which has been called dopachrome conversion factor or dopachrome oxidoreductase. We measured the dopa oxidase activity and dopachrome conversion activity in skin extracts of yellow mice and black mice that were mutant at the albino (C) locus. Extracts made from extreme‐dilution (ce/ce) mice do not have DO activity. Those from yellow extreme‐dilution mice do not have DC activity, while those from black, extreme‐dilution mice do. The DO and DC activities that characterize skin extracts made from platinum (cp/cp) yellow mice are similar to those of platinum black mice. These observations suggest possible mechanisms by which the functions controlled by the agouti and albino loci interact to control melanogenesis.
Male sterility caused by p6H and qk mutations is not corrected in chimeric mice
Authors: Handel Mary Ann , Washburn Linda L. , Rosenberg Michael P. , Eicher Eva M. 
Published: June 2005

AbstractIt is not known if the male sterility caused by the pleiotropic mutations p6H (pink‐eyed 6H) and qk (quaking) is intrinsic or extrinsic to spermatogenic cells. This question was addressed by juxtaposing mutant and normal cells in the testes of chimeric mice and determining whether the mutant germ cells could form functional sperm. Twenty‐one male chimeras consisting of normal cells and p6H/p6H or qk/qk cells were analyzed. For each, breeding productivity and testicular and sperm morphology were determined. Karyotypes and isozyme analyses were performed to identify the two cellular components of each chimera. All male chimeras that contained p6H/p6H, XY cells were sterile. Although some chimeras with a qk/qk, XY mutant component were fertile, none produced offspring from the homozygous qk component. Spermatids of the sterile chimeras showed abnormalities characteristic of the mutations.We conclude from this study that the presence of normal XY germ and somatic cells in the testis did not rescue the male sterile phenotype of homozygous p6H or qk XY germ cells. Therefore, the action of these mutant genes in causing sperm abnormalities and sterility is autonomous to the germ cells.
On the diversity of sperm basic proteins in the vertebrates: V. Cytochemical and amino acid analysis in Squamata, Testudines, and Crocodylia
Authors: Kasinsky H. E. , Mann M. , Huang S. Y. , Fabre L. , Coyle B. , Byrd E. W. 
Published: June 2005

AbstractThe variability of sperm basic proteins in representatives of three reptilian orders, Squamata, Testudines, and Crocodylia, has been examined by cytochemistry, acid‐urea polyacrylamide gel electrophoresis, and amino acid analysis of amidoblack‐stained bands. Snakes contain type 3B intermediate sperm basic proteins by cytochemical criteria. Electrophoresis of basic proteins from epididymis chromatin as well as from testis and ductus deferens cell suspensions shows two fast‐moving bands in the vicinity of herring protamine. These proteines are triprotamines containing about 27 mol % arginine, along with lysine and histidine. Lizards have type 1 protamines in their sperm nuclei cytochemically and also show a two‐banded electrophoretic pattern similar to that of snakes. However, these proteins are triprotamines, similar to those in snakes with 25 mol % arginine. It may be that these are testisspecific proteins of the spermatid stage in lizards since a cytochemical transition can be observed from type 3A intermediate proteins in spermatids of testis to type 1 protamine in mature sperm of ductus deferens. Turtles contain type 3A intermediate sperm basic proteins cytochemically and basic proteins from epididymis chromatin display both a prominent band and a minor band close to, but slightly slower than, the two bands for snakes and lizards. Amino acid analysis of these bands shows that these basic proteins are also triprotamines but with a higher level of arginine, about 48 mol %, than that in snake and lizard sperm proteins. Basic proteins from epididymis chromatin of a single Mississippi alligator show three main bands moving close to the bands of snakes, lizards, and turtles. These proteins have amino acid compositions typical for triprotamines, with 28–39 mol % arginine. The data indicate that the sperm basic proteins of representatives of 25 species in three reptilian orders are very similar, in contrast to the diversity of sperm protein types found in frogs (Kasinsky, Huang, Kwauk, Mann, Sweeney, and Yee: J. Exp. Zool., 203:109–126, '78; Kasinsky, Huang, Mann, Roca, and Subirana: J. Exp. Zool., 234:33–46, '85a). This appears to be part of a macroevolutionary trend from diversity of sperm basic proteins in frogs to relative constancy in reptiles (Kasinsky, Mann, Pickerill, Gutovich, and Byrd, Jr.: J. Cell Biol., 91:1879, '81; Kasinsky, Mann, Lemke, and Huang: In: Chromosomal Proteins and Gene Expression, Plenum Press, New York, pp. 333–352, '85b). We present the hypothesis that one factor for such a trend resides in the fact that fertilization is internal in reptiles but external in anurans.
The histogenesis of the rat adrenal cortex: A study based on histologic analysis of mosaic pattern in chimeras
Authors: Iannaccone P. M. , Weinberg W. C. 
Published: June 2005

AbstractA series of chimeric rats was used to investigate the histogenesis of the adrenal cortex. These animals were produced by amalgamating preimplantation embryos of two congenic strains which express different alloantigens of the major histocompatibility system. The manner in which cells assort themselves during embryogenesis and organ renewal is amenable to analysis by using radiolabeled antibodies directed to the class I antigens. Mosaic pattern analysis of the adrenal cortex of these rats revealed that a clonal pattern of division was maintained across all three histogenic zones of the organ, even in highly unbalanced chimeric combinations. No apparent relationship existed between the proportion of cell types and the area of contiguously similar lineage (patch size). In the series examined, the percentage of cells derived from the PVG‐RT1alineage varied from 5 to 85%. The number of parallel cords varied from 6 to 28. The pattern analysis of informative corners of cross sections of the gland supports the thesis that organ maintenance is the result of cell division from the outside of the cortex toward the inside medullary surface.
Scanning electron microscope studies of sperm incorporation into the zebrafish (Brachydanio) egg
Authors: Wolenski Joseph S. , Hart Nathan H. 
Published: June 2005

AbstractMorphological studies on the gametes and entry of the spermatozoan into the egg of the zebra danio, Brachydanio rerio, were conducted primarily with scanning electron microscopy. The spermatozoan showed a spherical head, which lacked an acrosome, a midpiece containing several mitochondria, and a flagellum. Observations of the unfertilized egg confirmed and extended prior studies showing a distinct cluster of microvilli on the plasma membrane, identified as the sperm entry site, beneath the inner micropylar aperture (Hart and Donovan, '83). The fertilizing spermatozoan attached to the sperm entry site within 5 seconds of the mixing of a gamete suspension. Binding to the egg microvilli appeared restricted to the equatorial surface of the spermatozoan. Fusion between the plasma membranes of the interacting gametes was followed by the formation of a distinct, nipple‐shaped fertilization cone. The sperm head was partially incorporated into the fertilization cone cytoplasm by 60 seconds postinsemination. The incorporation of the entire sperm head, midpiece, and a portion of the flagellum occurred between 1 and 2 minutes. During this time, the fertilization cone shortened and was transformed into a massive, blister‐like cytoplasmic swelling. Concurrently, upward movements of the ooplasm resulted in the gradual disappearance of the original depression in the egg surface containing the sperm entry site. The second polar body, fully developed by 10 minutes postinsemination, formed approximately 10–15 μm from the site of sperm penetration. Development of the fertilization cone, formation of the second polar body and exocytosis of cortical granules at the sperm entry site readily occurred in parthenogenetically activated eggs, indicating that these surface rearrangements do not require sperm binding and/or fusion.
An ecdysiotropic factor from brains of Heliothis virescens induces testes to produce immunodetectable ecdysteroid in vitro
Authors: Loeb M. J. , Brandt E. P. , Woods C. W. , Borkovec A. B. 
Published: June 2005

AbstractA factor extracted from brains of male larvae and pupae of the tobacco budworm, Heliothis virescens, caused immature testes to initiate immunoreactive ecdysteroid production in vitro. High–pressure size–exclusion chromatography removed endogenous ecdysteroids from most extract frac–tions. However, active fractions could only be detected when ecdysteroid (as 20‐hydroxyecdysone) was reincorporated into the bioassay medium. The active ecdysiotropin was susceptible to protease degradation. It may be a peptide of approximately 6–12 kD.
Uricoteley: Its nature and origin during the evolution of tetrapod vertebrates
Authors: Campbell James W. , Vorhaben Jean E. , Smith Darwin D. 
Published: June 2005

AbstractThe hepatic mechanism for detoxication of ammonia formed during amino acid gluconeogenesis in uricotelic vertebrates requires the intramitochondrial synthesis of glutamine by glutamine synthetase. This glutamine then serves as a precursor of uric acid in the cytosol. The evolutionary development of uricoteley thus required the localization of glutamine synthetase in liver mitochondria. The mechanism for the mitochondrial import of glutamine synthetase in uricotelic vertebrate liver is not yet known. Tortoises, extant relatives of the stem reptiles, possess both the ureotelic and uricotelic hepatic systems. It therefore seems likely that the genetic events allowing the mitochondrial localization of glutamine synthetase in liver occurred in the amniote amphibian ancestors of the stem reptiles. The selection of ureoteley by the theropsids and of uricoteley by the sauropsids were major events in the divergence and subsequent evolution of these two lines. Once established in the sauropsid line, uricoteley has persisted through to the higher reptiles, crocodilians, and birds. Uricoteley was in part responsible for the radiation of the archosaurs during the Triassic as a water‐conserving mechanism in the adult, thereby allowing them to invade the arid environments of that period. Contrary to dogma, uricoteley was probably of minor significance in the development of the cleidoic egg. Neither mammalian nor avian embryonic liver tissues catabolize amino acids to any great extent, so it is inappropriate to attribute to them a kind of “waste” nitrogen metabolism.
Periodic changes in the organs involved in the erythropoiesis of anemic newts
Authors: Frangioni Giuliano , Borgioli Gianfranco 
Published: June 2005

AbstractIn Triturus cristatus carnifex (Laurenti) newts rendered to tally anemic by treatment with acetylphenylhydrazine (APH) diluted in their tank water (25 mg/liter for 48 hours, with four changes) the recovery of erythron occurs through periodic cycles of mitotic activity in the erythropoietic tissue. These cycles determine a marked increase in blood erythrocyte concentration at regular intervals of about 1 month. The consequence of this trend is the alternation of ferritin and hemosiderin accumulation phases during periods of stasis with iron mobilization phases during periods of erythropoietic activity, which is particularly evident in the Kupffer cells of the liver. Iron mobilization and erythropoietic activity are strictly related to the periodic hypertrophy of some Bowman's capsule cells in the renal corpuscle, which were previously denominated “lactate sensitive cells” (LSC). The histochemistry, location, and behavior of LSC indicate that they are probably the site of erythropoietin production in the newt.
Intergeneric gene transfer of six isozyme loci in rainbow trout by sperm chromosome fragmentation and gynogenesis
Authors: Disney Jane E. , Johnson Kenneth R. , Thorgaard Gary H. 
Published: June 2005

AbstractTransgenic rainbow trout were produced by fertilizing albino rainbow trout eggs with gamma‐irradiated brook trout (ST) or rainbow trout (RT) sperm and then heat shocking the eggs at 29°C for 10 minutes to induce second polar body retention. Electrophoretic analyses of the RT × ST crosses confirmed the expression of paternal (brook trout specific) alleles at Ldh‐4, Mdh‐3,4, Mdh‐2, Aat‐1,2, Gpi‐3, and 6‐Pgd; the transfer frequency of these loci varied from 2 to 17%. These loci range from 8 to 48 cM from the centromere; proximity of introduced genes to a centromere does not appear to be a factor in retention and expression of foreign genes. Cytogenetic analyses of these same crosses revealed variable numbers and types of chromosome fragments and rings within individuals. Survival and pigment transfer in the resultant gynogenetic offspring varied considerably due to the individual female used in a particular cross. This female effect may have obscured effects due to dose of irradiation and species of male.
Pheromone strains of the Cosmopolitan pest, Nezara viridula (heteroptera: Pentatomidae)
Authors: Aldrich J. R. , Oliver J. E. , Lusby W. R. , Kochansky J. P. , Lockwood J. A. 
Published: June 2005

AbstractSexually mature males of the sourthern green stink bug, N. viridula, release a pheromone attractive in the field to conspecific females, males, and late‐stage larvae and to the parasitoid Trichopoda pennipes (Diptera: Tachinidae). The pheromone blend typically includes (Z)‐α‐bisabolene (17%), trans‐ and cis‐1,2‐epoxides of (Z)‐α‐bisabolene (44 and 15%, respectively), (E)‐nerolidol (1.4%), and n‐nonadecane (7.4%). The existence of Nezara pheromone strains, first suggested by differential Trichopoda parasitization of geographically isolated N. viridula populations, has been chemically verified.
Ganglionic circulation and its effects on neurons controlling cardiovascular functions in Aplysia californica
Authors: Furgal Sheryl M. , Brownell Philip H. 
Published: June 2005

AbstractThe abdominal ganglion of the mollusk Aplysia californica receives most of its blood supply through a small caudal artery that branches off the anterior aorta near its junction with the heart. Injection of an ink/gelatin mixture into the caudal artery revealed a consistent pattern of arterial branching within the ganglion and a general proximity of larger vessels to identified neurons controlling circulation in this animal. This morphological arrangement was particularly evident for the heart excitor interneuron, cell L10, which lies next to the caudal artery near its entry into the ganglion. In electrophysiological experiments, L10 was excited when blood flow or oxygen tension within the ganglion was reduced. This effect was expressed as a gradual increase in impulse frequency of L10 and conversion from tonic to bursting mode of spike discharge. L10 follower cells in the RB and LD neuron clusters were affected synaptically by the changes in L10 activity, while other follower cells (L3 and RD neurons) responded independently of L10's synaptic influence. The neurosecretory white cells (R3 to R14) that innervate the major arteries and pericardial tissues were also excited when ganglionic circulation was interrupted. In innervated preparations of the heart and respiratory organs, decreased circulation through the abdominal ganglion stimulated a transient increase in the rate and amplitude of respiratory (gill) pumping and pericardial contractions and caused a sustained increase in activity of the heart. Both responses increase cardiac output and both appear to involve a direct influence of ganglionic circulation on interneurons controlling the gill and heart. These results indicate that the cell‐specific patterns of excitation and inhibition caused by fluctuations in ganglionic circulation may be important factors for maintaining circulatory homeostasis in this animal.