bluuebunny/crossref_metadata_2025_split huggingface dataset:
In vitro biosynthesis and secretion of rabbit epididymal secretory proteins: Regulation by androgens
Authors: Regalado F. , Nieto A. 
Published: June 2005

AbstractThe biosynthesis and secretion of epididymal proteins were studied in an in vitro system using explants from rabbit epididymis cultured in a defined medium. Epididymal explants actively incorporated [35S]methionine into cellular proteins, about 7% of them being secreted into the medium. SDS‐PAGE of the labeled proteins secreted to the medium showed regional differences in their synthesis and secretion along the epididymal tract. Castration resulted in the inhibition of the synthesis and secretion of at least two polypeptides of Mr 150,000 and 21,000, but at the same time induced the appearance of other polypeptides. Immunoprecipitations with a specific antibody indicated that the variations in the amounts of the secreted 21 kDa component were associated with differences in its rate of synthesis. Epididymis from immature rabbits synthesized some polypeptides that are repressed in the adult state. The results suggest a dual effect of testosterone on rabbit epididymal secretory proteins.
Presence of thermal hysteresis producing antifreeze proteins in the antarctic mite, Alaskozetes antarcticus
Authors: Block William , Duman John G. 
Published: June 2005

AbstractThe presence of hemolymph thermal hysteresis antifreeze proteins is described in both the nymphs and adults of the Antarctic oribatid mite, Alaskozetes antarcticus collected from Signy Island in the South Orkney Islands. These proteins, functionally similar to the antifreeze proteins of polar marine fish and certain cold‐tolerant insects, lower the freezing point of water by a noncolligative mechanism while not significantly affecting the melting point, thus producing their characteristic thermal hysteresis. This is the first finding of these proteins in mites and the first description of them in an arthropod from the southern hemisphere.
Levels of tyrosinase and its mRNA in coat‐color mutants of C57Bl/10J congenic mice: Effects of genic substitution at the agouti, brown, albino, dilute, and pink‐eyed dilution loci
Authors: Tamate Hidetoshi B. , Hirobe Tomohisa , Wakamatsu Kazumasa , Ito Shosuke , Shibahara Shigeki , Ishikawa Kiichi 
Published: June 2005

AbstractThe levels of tyrosinase activities, tyrosinase cross‐reacting material (TY‐CRM), and tyrosinase mRNA were determined for skins from five congenic strains of mice (Mus musculus) with different coat colors. The dopa oxidase activity and melanin formation activity were directly proportional to the abundance of TY‐CRM in all of the mutants. The levels of the enzyme activities and TY‐CRM were increased in brown (b/b) and dilute (d/d) mice, while they were reduced in agouti (A/A) and pink‐eyed dilution (p/p) animals. In albino (c/c) mice, the tyrosinase activities and melanin formation activity were scarcely detectable, and no TY‐CRM was observed.Contrary to these, the levels of tyrosinase mRNA in agouti and albino mutants were almost the same as that in black mice, and those in brown and dilution mutants were 20–30% higher than that in black mice. These results indicate that the mutations at the brown and dilute loci exert their influence on the tyrosinase mRNA level, presumably by affecting the transcription of the tyrosinase gene, and that the mutations at the agouti and albino loci exert their influence on the TY‐CRM level by regulating translation of tyrosinase mRNA and/or post‐translation modification of the enzyme.
Melanophore dispersion in northern amphibian larva induced by exposure to cold
Authors: Moriya Tsuneo , Miyashita Yoko 
Published: June 2005

AbstractIsolated tails from larvae of the northern amphibians Rana chensinensis and Hynobius retardatus showed light skin color in physiological salt solution at room temperature. However, when the tails were exposed to cold, they became dark. Microscopic observation revealed that exposure to cold caused reversible dispersion of melanin granules within integumental melanophores. There was no darkening, however, in the tail of the Xenopus tadpole at low temperatures, as the dispersion effect of melanophore‐stimulation hormone (MSH) on melanophores in Xenopus was blocked. Calcium ions are required for the action of MSH, but the effect of cold on melanophore dispersion observed in R. chensinensis and H. retardatus was not dependent on calcium ions. Beta adrenergic agents dispersed the melanophores of isolated tail from these amphibian larvae and propranolol antagonized the effect. However, during exposure to cold, this beta antagonist failed to inhibit the melanophore dispersion.
Discrete localization of distinct alkaline phosphatase isozymes in the cell surface of silkworm midgut epithelium
Authors: Azuma Masaaki , Eguchi Masaharu 
Published: June 2005

AbstractAlkaline phosphatase (ALP) isozymes were localized in the larval midgut epithelium of the silkworm, Bombyx mori (Insecta: Bombycidae) by immunohistochemistry with the peroxidase‐conjugated antibody technique. The monospecific antibodies were produced against purified membrane‐bound ALP (m‐ALP) and soluble ALP (s‐ALP), respectively. The anti‐(m‐ALP)‐antibody did not cross‐react with the purified s‐ALP and vice versa. The m‐ALP was localized at the brush border of columnar cells in the middle and posterior midgut epithelium, but very weakly at that in the anterior midgut. In contrast, the s‐ALP was localized at the apical surface of goblet cells throughout the length of midgut. The extent of positive staining gradually increased toward the posterior midgut, where strong staining was also detected in the goblet cavity. From these results, it is concluded that two ALP isozymes distribute in the different cell types of Bombyx midgut epithelium and that the regional differentiation along the length of midgut exists on columnar and goblet cells.
Plasminogen activator activity is associated with neural crest cell motility in tissue culture
Authors: Erickson Carol A. , Isseroff R. Rivkah 
Published: June 2005

AbstractWe have examined the possibility that proteases such as plasminogen activator (PA) contribute to the extraordinary motile capability of neural crest cells. We show that trunk neural crest cells that migrate from isolated neural tubes in vitro produce PA and that the level of cell‐associated PA increases dramatically after 8 days in culture. This increase is not the result of differentiation or time in culture, because neural crest cell clusters that form on top of the neural tube and differentiate into pigment cells but are immotile produce very low levels of PA. If these clusters are removed from the neural tube and replated on a plastic substratum where they migrate, the level of PA associated with the cells increases dramatically, suggesting that PA production is associated with motility. Inhibitors of PA/plasmin activity significantly reduce neural crest cell motility in vitro, further supporting the idea that proteases are important in neural crest cell migration.
Cells from Rana pipiens gastrulae and arrested hybrid gastrulae show differences in adhesion to fibronectin‐Sepharose beads
Authors: Johnson Kurt E. , Silver Michael H. 
Published: June 2005

AbstractExperiments were performed to examine adhesion of Rana pipiens gastrula cells and arrested hybrid gastrula cells to fibronectin‐Sepharose beads (FN‐beads). Blastula cells from both normal and hybrid embryos show poor adhesion to FN‐beads. Beginning at the early gastrula stage, however, normal cells show a progressively increasing tendency to adhere to beads. In two different arrested hybrid embryos, cells from all developmental stages lack the ability to adhere to beads. A third hybrid shows an increase and then a decrease in cell‐bead adhesion. A fourth hybrid shows a late increase in cell‐bead adhesion in animal‐half cells and no increase at all in vegetal‐half cells. Blastula‐stage cells have the ability to adhere to con A–beads and two kinds of Cytodex beads but will not adhere to FN‐beads. Similarly, some cells from arrested hybrid embryos lack the ability to adhere to FN‐beads but will adhere to con A–beads and cytodex beads. Observations in the light and scanning electron microscope show that normal cells form lamellipodia on FN‐beads and move about actively on them, much like they do in vivo on surfaces coated by fibrils containing fibronectin. For adherent hybrid cells attached to beads, one kind does so by small pseudopodia but does not move on them and another kind forms active lamellipodia at the tips of fusiform cells and moves on beads.
Identification of puberty‐accelerating pheromones in male mouse urine
Authors: Nishimura K. , Utsumi K. , Yuhara M. , Fujitani Y. , Iritani A. 
Published: June 2005

AbstractGas chromatography–mass spectrometry was employed to identify the two volatile amines in male mouse urine. These amines were much less concentrated in urine of castrated males. The identified amines, isobutylamine and isoamylamine, were assayed for the potential of puberty acceleration in postweaning female mice. A total of 105 young female mice were exposed to one of the following five odors: distilled water (control), 0.1 M isobutylamine, 0.1 M isoamylamine, a mixture of 0.05 M isobutylamine and 0.05 M isoamylamine, or fresh male mouse urine. The mixture of these amines accelerated the vaginal opening of young females. Except for the control, all experimental odors accelerated the first vaginal estrus in ICR strain mice.
Cardiovascular anatomy and physiology of the black‐lip abalone, Haliotis ruber
Authors: Russell C. W. , Evans B. K. 
Published: June 2005

AbstractThe anatomy of the cardiovascular system of Haliotis ruber is described on the basis of observations from dissection, routine histology, and scanning electron microscopy of vascular casts and critical‐point dried tissue. The finest channels, lacunar tissue spaces, were around 10 μm and appear to lack an endothelial lining. A vascular connection, which exists between the cephalic arterial sinus and the cephalopedal venous sinus, may allow redirection of blood back to the heart during circumstances in which blood flow through the pedal vessels is prevented. 5‐Hydroxytryptamine (5‐HT) immunoreactive nerves were observed in atrial and ventricular walls, pericardium, cephalic arterial sinus, and afferent ctenidial vein. In unrestrained animals, pairs of in vivo pressure measurements were made from the right atrium, the ventricle, the pericardial chamber, the right efferent ctenidial vein, and the renal sac. All sites showed pulsatile pressures of low magnitude. Ventricular systolic:diastolic pressures were typically 8:4 cm water. In unrestrained animals, heart‐rate responses to changes in water temperature and pO2 were established and show H. ruber to be an imperfect regulator with respect to O2. Structural characteristics of the heart and vascular anatomy, pressure measurements, and heart rate are discussed in relation to whole animal function.
Relationships between spleen and respiration in the newt
Authors: Frangioni Giuliano , Borgioli Gianfranco 
Published: June 2005

AbstractSpecimens of newt, Triturus cristatus carnifex (Laurenti), anesthetized by submersion in 0.2% chlorbutol in tap water for 15 min, and then placed out of water in a damp terrarium, show hypertrophy of the spleen that in 2 hr gradually increases from 0.31 ± 0.12% with respect to body weight to 1.56 ± 0.26% (means and standard deviation calculated for groups of six animals). Other anesthetics either do not produce hypnosis (Veronal), do not have a prolonged enough effect (ethyl ether, chloroform), or induce vasodilatation, which prevents hypertrophy (MS‐222, urethane). The spleen hypertrophy, seen histologically to be due exclusively to blood congestion, is not caused by either a pharmacological effect of the chlorbutol or by the hypnotic state, as it does not appear in submerged anesthetized animals, unless the water is constantly stirred by a magnetic agitator, and can be reversed depending on the ventilation of the animal's skin. The spleen hoards blood when oxygenation is good (in air or stirred water) and releases this supply in the bloodstream when oxygenation is insufficient (in still water). The hypoxic “diffusion boundary layer”, which, in still water, forms around the immobile newts, hampers respiratory exchange and stimulates the spleen contraction. This mechanism and its relationship to oxygenation has been demonstrated statistically in unanesthetized newts as well, in both air and water, despite the interference of two contrasting factors—lung respiration and spontaneous motor activity—absent in anesthetized animals. Congestion and decongestion of the spleen are the physiological mechanisms compensating for variations in the level of oxygenation, an alternative to the “capillary recruitment” described by Poczopko (Zool Pol 6:161–175, 1957) and Burggren and Moalli (Respir Physiol 55:379–392, 1984) in many amphibians that appears to be absent in newts. The newt spleen, known to play a lesser role in erythropoiesis and destruction of aged erythrocytes than that traditionally assigned to it (Frangioni and Borgioli: J Exp Zool 243:409–416, 1987; 247:244–250, 1988), is thus of primary importance in respiration.
Analysis of proteins secreted by mouse embryos developing in vivo and in vitro
Authors: Nieder Gary L. 
Published: June 2005

AbstractProteins secreted by mouse blastocysts developing in vitro were compared to those from blastocysts developing in utero to determine if a simple medium supporting blastocyst development also supports secreted protein expression. In‐vivo embryos were collected on days 3, 4, or 5 of pregnancy and incubated in 35S‐methionine to produce conditioned medium containing released, labeled proteins. Embryos for culture were collected on day 3 and after 48 or 72 h labeled conditioned medium was produced. Labeled proteins were separated by two‐dimensional electrophoresis and compared using a digital image analysis system. Day 3 embryos did not release proteins in detectable amounts, although synthesis of intracellular proteins was substantial. Day‐4 and ‐5 blastocysts released proteins in increasing amount and complexity, consistent with previous results. When day‐3 embryos were cultured in medium containing 4 mg/ml BSA for 48 h, secreted protein patterns were similar but not identical to those of day‐5 uterine blastocysts. Although most of the proteins produced by uterine blastocysts were secreted by cultured embryos, differences were found in the relative quantities of certain proteins. Neither crystallized BSA nor polyvinyl alcohol at 4 mg/ml supported development of protein secretion as well as the crude fraction‐V BSA. Blastocysts restricted to the oviduct also exhibited quantitative differences in protein secretion patterns compared to uterine blastocysts. Thus, although blastocyst development and the expression of many secreted proteins are supported outside the uterus, the full pattern of secretion characteristic of the peri‐implantation embryo may be dependent on specific uterine influences.
Hypercapnic and hypocapnic hypoxia in the lugworm arenicola marina: A 31P NMR study
Authors: Kamp Günter , Juretschke Hans Paul 
Published: June 2005

AbstractUsing the noninvasive method of 31P nuclear magnetic resonance(NMR) spectroscopy, the influence of hypoxia on intracellular pH (pHi) and on the energy metabolism was studied in the lugworm Arenicola marina.1. During hypercapnic hypoxia (induced by the animal itself), pHi dropped from 7.3 ± 0.1 (n = 6) to 6.5 ± 0.1 (n = 4) within 24 hours, whereas during hypocapnic hypoxia pHi decreased by only 0.3 units (n = 4). The change in pHw (pH of the ambient water) was similar: strong acidification from about 8.1 to 6.1 during hypercapnic and moderate acidification to 7.8 during hypocapnic hypoxia.2. Mobilization of phosphagen (phosphotaurocyamine) occurred faster during hypercapnic than hypocapnic hypoxia. Anaerobic end products (propionate and acetate), however, accumulated to a greater extent during hypocapnic than hypercapnic hypoxia.3. Conclusion: The severe acidosis found during hypercapnic hypoxia depends on the amount of CO2 accumulation rather than on the amount of glycolytic end products. On the other hand, the lower accumulation of glycolytic end products and the faster mobilization of phosphagen with severe acidosis seem to reflect a regulatory effect of pHi on anaerobic metabolism.
Ecdysteroids and regeneration in the fiddler crab Uca pugilator
Authors: Hopkins Penny M. 
Published: June 2005

AbstractRegeneration of lost walking legs in the fiddler crab Uca pugilator is divided into three distinct phases—wound healing, basal growth, and proecdysial growth. By means of HPLC/RIA analysis of levels and composition of endogenous ecdysteroid hormones and in vitro assays of 14C‐leucine incorporation, we have determined that the transition between anecdysis and proecdysis is the point at which limb bud growth is most affected by ecdysteroids. The growth that occurs during proecdysis is programmed during the anecdysis/proecdysis transition by a small peak of ecdysteroids (Peak I). Early exposure to 20‐hydroxyecdysone at this critical window is necessary for further proecdysial growth of limb buds. The later peak of ecdysteroids (Peak II) seen in the hemolymph of these crabs during late proecdysis does not seem to be involved in the regeneration process.
Effect of maternal age on the incidence of digynic triploidy in LT/SV strain mice: Implications for the ovulation of primary and secondary oocytes in this strain
Authors: Speirs S. , Kaufman M. H. 
Published: June 2005

AbstractLT/Sv strain mice ovulate both primary and secondary oocytes, which are fertilisable, giving rise to digynic triploid and normal diploid fertilised conceptuses, respectively. Since the proportion of primary and secondary oocytes ovulated in our earlier studies varied widely among females, we investigated whether the proportion of primary oocytes ovulated in LT/Sv strain mice was influenced by maternal age. Females 6, 12, 18, 24, and 30 weeks old were mated with F1 hybrid males. The females were autopsied on the 10th day of gestation, and the intact conceptuses or extraembryonic membranes analysed cytogenetically.Since no selective loss of the triploids occurs up to the 10th day of gestation, analysis at this time also provides indirect information on the proportion of primary and secondary oocytes ovulated. We observed 1) that the overall incidence of triploidy decreased from 55% in the 6‐week‐old females to 6% in the 30‐week‐old group; 2) that the number of females from which both triploid and diploid embryos were recovered decreased with increased maternal age; 3) that a substantial decrease in the proportion of triploid embryos was observed in those females in which both triploid and diploid embryos were recovered, in relation to increased maternal age; 4) that there was no overall decrease in the total number of implants with increasing age; and 5) that there was no increase in the incidence of resorptions with increasing maternal age. We believe that no comparable relationship between the ovulation of primary and secondary oocytes and maternal age has previously been reported.
Regulation of body volume by the peripheral nervous system of the terrestrial slug Ariolimax columbianus
Authors: Martin Arthur W. , Deyrup‐Olsen Ingrith , Stewart Doris M. 
Published: June 2005

AbstractResponses to mechanical and chemical stimulation have been studied in an in vitro preparation of the body wall of the land slug Ariolimax columbianus. This preparation (posterior chamber, PC) is separated from the head ganglia and therefore has only peripheral nervous control. The volume contained within the PC (normally filled with viscera and hemolymph) is determined by 1) contraction or relaxation of muscle cells, causing exchange of fluid between the PC and the attached manometer that controls pressure within the PC; 2) secretion by epithelial channel cells moving fluid from inside the PC to the outside across the epithelial surface.The PC maintained at constant internal pressure responded to mechanical stimulation (at ca. 1 Hz) of the epithelium with a brief burst of secretion. Prolonged (45 minutes) stretch of the body wall by maintenance at 11 torr or above resulted in intermittent pulses of secretion and muscle contraction. At very high pressure muscle contraction was suppressed, and secretion volumes were huge, gradually restoring the volume of the PC to its initial value (autoregulation).When PCs were immersed in fluid containing garlic extract, skin receptors responded, initiating secretion comparable to the effects of mechanical stimulation in both amount and duration. Other chemicals (including capsaicine, cysteic acid, and geraniol) known to be aversive to pulmonates in vivo did not activate the secretory response.
Isosmotic swelling of skate (Raja erinacea) red blood cells causes a volume regulatory release of intracellular taurine
Authors: Goldstein Leon , Brill Susan 
Published: June 2005

AbstractAnimal cells swell when placed in a hypotonic medium and then regulate their volume by releasing intracellular solutes. The aim of this study was to determine whether hypoosmolarity or cell swelling is the stimulus that triggers the release of solutes. Swelling skate red blood cells (RBC) by placing them in isosmotic media containing rapidly penetrating solutes (NH4Cl, ethylene glycol) caused increased release of taurine from the cells. Isosmotic swelling also increased the cellular levels of radiolabeled diacylglycerol, a second messenger previously implicated in volume regulation by skate RBC. These results indicate that the release of intracellular solutes by hypoosmotically stressed skate RBC is brought about by cell swelling.
Phenotypic characterization of the transgenic mouse insertional mutation, legless
Authors: McNeish John D. , Thayer Jean , Walling Karen , Sulik Kathy K. , Potter S. Steven , Scott William J. 
Published: June 2005

AbstractIn this report, we describe the dysmorphologic phenotype associated with the transgenic insertional mutation legless. This autosomal recessive, perinatally lethal mutation results in an interesting pleiotropic array of congenital malformations. The phenotype of the legless mutation in homozygous perinatal mutants is compared to wild‐type nontransgenic and heterozygous siblings. Skeletal, craniofacial, and visceral malformations are characterized. We have observed by skeletal analysis a consistent loss of distal hindlimb structures, as well as the loss of distal forelimb structures with a predilection for the preaxial side of the developing forelimb. Craniofacial malformations commonly observed appear to represent a range of severity of affect, with the mildest manifestation evident as apparently shallow lateral clefts of the upper lip and mild midfacial clefts accompanied by clefts of the secondary palate. At the severe end of the spectrum, the midline clefts of the face (and secondary palate) are very wide, with obvious accompanying frontonasal encephaloceles and overt lateral clefts of the upper lip. Examination of the mutant brain has demonstrated marked defects in the anterior structures, particularly the olfactory lobes and cerebrum, in greater than 90% of the brains studied. Observation of the internal viscera has identified transposition of thoracic and abdominal organs in approximately 50% of the mutant offspring. The limb, head, and visceral defects were not observed in the wild‐type nontransgenic or heterozygous siblings. Transgenic insertional mutations leading to congenital malformations are useful because the transgene sequence may serve as a tag to facilitate molecular retrieval. Analysis of the flanking DNA sequences will allow the identification of the interrupted gene. A complete description of the mutant phenotype will assist in the understanding of this genetic locus.