bluuebunny/crossref_metadata_2025_split huggingface dataset:
Isolation of Drosophila mutants with abnormal proboscis extension reflex
Authors: Kimura Ken‐Ichi , Shimozawa Tateo , Tanimura Teiichi 
Published: June 2005

AbstractDrosophila mutants with defects in their proboscis extension reflex (PER) were isolated for a genetic dissection of the PER system. Five mutant strains were screened from 35,000 mutagenized flies through a twostep screening: a mass test of sugar intake, followed by an individual PER test. Mutants were classified into three complementation groups: aperA (genetical map position, 1–22.1), aperB (1–0.6) and aperC (1–0.4). The aperA mutants showed incomplete penetrance and expressivity. Some flies did not extend their proboscises at all, while others did so only to either the right or the left side; the PERs of the rest were apparently normal. The aperB mutants showed abnormality in the direction of the PER: they extended their proboscises backward, instead of straight forward. The aperB mutation was temperature‐sensitive and its phenotype was expressed at a culture temperature above 25°C. The aperC mutation caused a PER defect in aged flies. Within 2 days of eclosion they showed normal PER, but 2 or more days after eclosion most of them had become unable to extend their proboscises. Later, about half of the aperC mutants recovered the PER ability. The anatomical site of action of these mutations seems to be in the neuromuscular or skeletomuscular system.
Stage‐specific changes in protein phosphorylation accompanying meiotic maturation of mouse oocytes and fertilization of mouse eggs
Authors: Endo Yoshihiro , Kopf Gregory S. , Schultz Richard M. 
Published: June 2005

AbstractCharacteristic changes in the patterns of protein phosphorylation occur during meiotic maturation of mouse oocytes from the time subsequent to germinal vesicle breakdown, through metaphase II, and following fertilization. These changes occur during both in vitro or in vivo maturation or fertilization. Three major classes of changes in total phosphoprotein synthesis are observed. In the first class, protein phosphorylations increase from the germinal vesicle stage until just after germinal vesicle breakdown and then decrease during progression to metaphase II and after fertilization. The second class is characterized by decreases in protein phosphorylation during maturation with subsequent increases in phosphorylation of these proteins after fertilization. The third class is characterized by protein phosphorylations that remain relatively constant during maturation but increase after fertilization; phosphotyrosine phosphoproteins comprise the major species. The radiolabeled protein and phosphoprotein composition of isolated germinal vesicles was also examined, and a phosphoprotein of Mr29,000 is found exclusively associated with the germinal vesicle. Since we have shown previously that 12‐O‐tetradecanoyl phorbol 13‐acetate inhibits fertilization (Y. Endo, R.M. Schultz, and G.S. Kopf, submitted), we examined the effects of this compound on the phosphoprotein patterns of metaphase II eggs. 12‐O‐Tetradecanoyl phorbol 13‐acetate treatment stimulates the phosphorylation of a specific phosphoprotein of Mr80,000.
Pigment cell pattern formation in amphibian embryos: A reexamination of the dopa technique
Authors: Tucker R. P. , Erickson C. A. 
Published: June 2005

AbstractNeural crest‐derived melanophores form species‐specific patterns in the dermis of amphibian embryos. Melanophore patterns may be generated by one of two general mechanisms: (1) pigment cell precursors disperse throughout the embryo, with melanophores differentiating in certain regions due to environmental cues, or (2) melanoblasts may localize in different regions as a result of a hierarchy of tissue affinities. Both of these mechanisms have been proposed to be responsible for the dorso‐ventral patterning of melanophores in Xenopus laevis. We have reexamined the distribution of melanoblasts in X. laevis and Taricha torosa using the dopa (3,4‐dihydroxyphenylalanine)‐staining technique. We have found that many of the dopa‐positive cells identified as melanoblasts by some researchers are actually not derived from the neural crest: (1) dopa‐positive cells in T. torosa were identified in the transmission electron microscope to be either leukocytes or erythrocytes, (2) in X. laevis dopa‐positive cells are found between the ectoderm and somites where neural crest cells are not found, and (3) X. laevis embryos surgically depleted of neural crest have dopa‐staining patterns identical to control embryos. Melanoblasts are apparently not found in the ventralmost regions of early T. torosa and X. laevis embryos, providing additional evidence for the role of differential tissue affinities in directing the formation of embryonic pigment cell patterns.
Phenotypic switching to long cilia effected by various proteases: Results With Dendraster excentricus and Stronglyocentrotus purpuratus blastulae
Authors: Riederer‐Henderson Mary Ann 
Published: June 2005

AbstractIncubation in trypsin effects a phenotypic switch from short to long cilia (> 30 μ) in hatched blastulae of the sea urchin, Arbacia punctulata. To determine how trypsin causes such a switch we tested whether the phenomenon was unique to the species, Arbacia, and to the protease, trypsin. With two other echinoderm species, the sand dollar, Dendraster excentricus, and the sea urchin, Strongylocentrotus purpuratus, trypsin incubation increased the percentage of long cilia. During incubation of D. excentricus in trypsin, the percentage of long cilia increased progressively from the normal 10% long cilia of the apical tuft to 45–50% long cilia covering 1/2–3/4 of the embryo. With S. purpuratus blastulae, however, the percentage of long cilia was lower (32–40%) and the results were more variable. Of the additional proteases tested with D. excentricus, elastase was more effective than trypsin in terms of the percentage of long cilia (58%), the mean length, and the broad distribution of lengths fromed. Thermolysin was about as effective as tryspin but chymotrypsin was much less so. Thus, increases in ciliary length were not unique to a particular echinoderm species or to incubation in trypsin. The magnitude of the change in length distribution, however, was species‐ and enzyme‐dependent. An extracellular or membrane component with differential susceptibility to various proteases may, therefore, be involved in altering ciliary length.
Ovary‐stimulating pheromone in the freshwater shrimp, Paratya compressa
Authors: Takayanagi Hiroshi , Yamamoto Yoshihiro , Takeda Naokuni 
Published: June 2005

AbstractIn the female shrimp, Paratya compressa, reared in the absence of males, ovarian development was usually delayed, whereas it occurred normally in females reared with mature males. Ovarian development also occurred in shrimps reared in water that contained an extract of the testis or the vas deferens. Therefore, it is proposed that mature, male shrimps secrete an ovary‐stimulating pheromone which accelerates ovarian development, the source of which may be male organs such as the testis or the vas deferens.
Eye factors and lens‐forming transformations of outer cornea in Xenopus laevis larvae
Authors: Bosco L. , Filoni S. , Cioni C. , Bernardini S. 
Published: June 2005

AbstractOuter cornea of lensectomized Xenopus laevis tadpoles at state 50 (according to Nieuwkoop, P.D. and Faber, J., ('56) Normal Table of Xenopus laevis, Daudin, North‐Holland, Amsterdam, pp. 1–243) was removed 3, 7 and 10 days after lensectomy and implanted between the outer and the inner cornea of larvae of the same species at stage 51–52. In these conditions, the implanted outer cornea remained isolated from the retinal factor of the vitreous chamber, although it received the nutritional factors normally reaching the outer cornea. Results show that lens‐forming transformation process of the outer cornea is arrested, and lens‐forming structures undergo regression at speed which increases with increasing precocity of the stage of lens‐forming transformation undergone by the implanted cornea. These data suggest that the process of lens‐forming transformation is not a single‐step process, but a sequence of interactions extending over a long period of time requiring the continuous presence of the retinal factor in the vitreous chamber until complete differentiation of the lens is achieved.
Immunochemical evidence that the single lactate dehydrogenase of lampreys is more similar to LDHB4 than to LDHA4 of hagfish
Authors: Baldwin J. , Lake P. S. , Moon T. W. 
Published: June 2005

AbstractThe tetrameric lactate dehydrogenases (LDH) of vertebrates contain several different subunits that arose by gene duplication. While the A and B subunits occur in all classes of gnathostomes, the enzymes of agnathans appear to represent two stages in the evolution of vertebrate LDH. Lampreys of the family Petromyzontidae have a single enzyme classified as LDHA4, while hagfish possess both A and B subunits which form only the two homopolymers LDHA4 and LDHB4. It is generally assumed that the original vertebrate LDH was an A4 type, that duplication to give the B subunit occurred prior to the divergence of lampreys and hagfish, and that modern lampreys subsequently lost expression of the B gene. Lactate dehydrogenases were purified from representatives of all three lamprey families, and it was confirmed that members of the Mordaciidae and Geotriidae also possess single tetrameric LDH enzymes containing one subunit type. The kinetic properties of the lamprey LDH enzymes were compared with the LDH homopolymers of hagfish, skate, and sardine. These properties did not allow the lamprey enzymes to be unequivocally identified as either LDHA4 or LDHB4. Immunochemical titration using antisera against lamprey and hagfish LDH homopolymers demonstrated that the lamprey LDH enzymes showed greater immunochemical similarity to LDHB4 than to LDHA4 of hagfish. It is concluded that there is little evidence for the claim that the original vertebrate LDH was an A4 rather than B4 type.
Protein uptake and transport by trophotaenial absorptive cells in two species of goodeid embryos
Authors: Schindler Joachim F. , De Vries Uwe 
Published: June 2005

AbstractNear‐term embryos of two goodeid species (Xenotoca eiseni and Girardinichthys viviparus) have been exposed to horseradish peroxidase (HRP) and/or cationized ferritin (CF) within the ovarian cavity. The trophotaenial absorptive cells (TACs) of X. eiseni have an apical endocytotic complex and, therefore, readily ingest tracer molecules from ambient proteinaceous liquids. Internalized solutes accumulate in large apical storage vacuoles. In double‐tracer experiments, the two proteins are mostly sorted each into separate vacuolar compartments. After exposure for several hours, reaction product of HRP can be localized in a lamellar membranous complex, which underlies the peripheral plasma membranes and communicates with the intercellular space. Some vesicles carry small portions of ferritin molecules to the basal or basolateral cell surface and eventually exteriorize their contents. No activity of an acid phosphatase (AcPase) is testable in elements of the endocytotic system before and after exposure to tracer proteins. In G. viviparus, the TACs are lacking an endocytotic apparatus. Consequently, the rate of solute movements into the cells is relatively low, and the total amounts of ingested proteins remain rather moderate, even after 24 h of continuous exposure. The binding of CF to cell surface components apparently stimulates micropinocoytotic activity. During the endocytotic process, an apical canalicular system is formed, which subsequently develops into multivesicular bodies (MVBs). These were seen to arise more numerously if the tracer medium contains CF. The effect of a sorting mechanism, resulting in differently labeled storage compartments, is not observable in the TACs of G. viviparus. Some of the internalized ferritin is transferred to the basal and basolateral plasma membranes. The vesicular or short tubular transport vehicles seem to contain only ferritin granules, even when the marker medium is composed of CF and HRP. Clusters of CF molecules can be seen fairly regularly in the lamina lucida of the basement membrane and in erythrocytes of the underlying capillary plexus. A scheme is presented that depicts the mechanisms of protein uptake and transport of either HRP or CF by TACs of both G. viviparus and X. eiseni.
Exogenous GnRh overrides the endogenous annual reproductive rhythm in green iguanas, Iguana iguana
Authors: Phillips John A. , Frye Fred , Bercovitz Arden , Calle Paul , Millar Robert , Rivier Jean , Lasley Bill L. 
Published: June 2005

AbstractFemale green iguanas, Iguana iguana, were caught in Belize, Central America (17°N), in December, at the onset of seasonal gonadal activity. The animals were immediately transferred to San Diego (32°N). Ovarian follicular development continued, with peak plasma hormone levels measured in January and February; 200 pg/ml for progesterone (P) and 800 pg/ml for total estrogens (Et = estradiol [E2] + estrone [E1]). E2 was the predominant estrogen throughout the cycle. Follicular atrophy was indicated in April with circulating progesterone and estrogen levels decreasing to baseline (refractory phase) levels (P = 20 pg/ml; Et = 50 pg/ml). Approximately midway through the refractory phase of their annual reproductive cycle (late May), either the D‐Arg6 analog of Chicken II or mammalian GnRH was administered via intraperitoneal osmotic pumps for 14 days to nine females. The analog of chicken II induced a fivefold increase in total circulating estrogens within 3–4 days after induced a fivefold increase in total circulating estrogens within 3–4 days after implantation. Both continuous and pulsatile delivery of the chicken II analog produced a similar pattern of steroidogenic response. A radical sham control animal showed no increase in steroidogenesis. Mammalian GnRH produced a pattern of similar duration, although the magnitude of the steroidogenic response was only half that produced by the chicken II analog. Estrogen titers approached baseline levels in all treatment groups two days after treatment ceased. Progesterone levels increased in all treatment groups during the delivery of exogenous GnRH, although the increases were not consistent. Untreated male cagemates housed with treated females exibited increased territoriality, courtship behavior, and mating, which began on day 4 or 5 of the treatment period. The control female was not courted by its male cagemate.
Immunofluorescent localization of the Ca2+‐dependent proteinase and its inhibitor in tissues of Crotalus atrox
Authors: Kleese William C. , Goll Darrel E. , Edmunds Tim , Shannon John D. 
Published: June 2005

AbstractThe native 108,000 dalton Ca2+‐dependent proteinase (CDP) and its 115,000 dalton protein inhibitor (CDPI) were purified from bovine skeletal muscle using native polyacrylamide gel electrophoresis and were used to elicit antibody production in rabbits and BALB/c mice. Polyclonal antibodies were purified as IgG fractions by column chromatography; monoclonal antibodyies were produced by the hybridoma technique. Indirect immunofluorescence localizations of CDP and CDPI in tissues of Crotalus atrox show both proteins to be ubiquitous. Both occur in the cytoplasm and are absent from the cell membrane and the nucleus; CDPI is also present in the I‐band of skeletal muscle.
Characterization of renal prolactin‐binding sites of two amphibians (Ambystoma tigrinum and Rana catesbeiana) and a reptile( Pseudemys scripta elegans)
Authors: Tarpey John F. , Nicoll Charles S. 
Published: June 2005

AbstractThe specific binding of 125I‐ovine prolactin (oPRL) to renal membrane preparations from Pseudemys scripta elegans, Ambystoma tigrinum, and Rana catesbeiana was characterized. All three membranes showed specific oPRL binding that was dependent upon time, temperature, pH, and membrane concentration. Scatchard analysis of the binding of 125I‐oPRL revealed high‐affinity sites with KA values of 2.1 × 1010, 3.6 × 1010, and 1.25 × 1010 M−1 for kidney membranes of Pseudemys, Ambystoma, and Rana, respectively. In addition, there was a low‐affinity site on the Ambystoma membranes. The binding capacities ranged from 31 to 70 fmol/mg of membrane protein. The hormonal specificity of these membranes was studied by competing increasing amounts of oPRL, human growth hormone (hGH) derived from recombinant DNA techniques, bovine (b) GH, and human placental lactogen (hPL) with 125I‐oPRL. The oPRL standard and hGH were the most potent competitors in all three assays, although hGH was not as potent as the oPRL. Human PL was moderately active in the turtle kidney assay, weakly active in the Ambystoma radioreceptor assay, and inactive in the bullfrog assay. Bovine GH had low potency on the turtle membranes and was inactive in the amphibian assays. The results of these studies indicate that the characteristics of renal PRL receptors of Pseudemys, Ambystoma, and Rana are similar to those of lactogenic receptors throughout the vertebrates. In addition, these data provide evidence for the first time of renal PRL receptors in a reptile.
Seawater‐acclimation and the thyroidal response to thyrotropin in juvenile coho salmon (Oncorhynchus kisutch)
Authors: Specker Jennifer L. , Kobuke Louise 
Published: June 2005

AbstractJuvenile coho salmon (Oncorhynchus kisutch) were acclimated to seawater beginning at one of two stages of development. The first group was seawater‐acclimated before the 1‐ to 2‐month period of elevated plasma thyroxine (T4) concentration associated with the parr to smolt transformation (smoltification). The second group was seawater‐acclimated midway through the period of elevated T4 levels. Two measures of thyroid activity were used to compare seawater‐acclimated salmon with their controls remaining in fresh water. The baseline concentrations of thyroid hormones were assayed throughout a 9‐ or 10‐week period, and at the end of 9 or 10 weeks the responsiveness to a single injection of 0.2 IU bovine thyrotropin was measured. Transfer to seawater before the smoltification‐associated T4 elevation prevented the rise in thyroid hormone concentrations and reduced the response to bovine thyrotropin. Transfer of salmon during the period of elevated T4 levels did not change thyroid hormone concentrations; however, the response to thyrotropin was greater in seawater‐acclimated fish than in fish still in fresh water. We conclude that the longterm response of the thyroid to seawater acclimation is partly a function of the stage of development at the time of transfer.
Cell size in triploid salmon
Authors: Small Susan A. , Benfey Tillmann J. 
Published: June 2005

AbstractThere is a uniform increase in nuclear and cell size of erythrocytes, leukocytes, brain cells, and retinal cells in triploid coho and Atlantic salmon. In spite of the potentially drastic effects of this on their physiology and behavior, triploid fish appear to function as successfully as normal fish under aquaculture conditions. Triploid fish are easily produced, reared, and identified and should make useful tools for basic and applied research.
Luteal progesterone production and regulation in the viviparous dogfish, Squalus acanthias
Authors: Tsang Paul , Callard Ian P. 
Published: June 2005

AbstractAlthough vertebrate viviparity has evolved in parallel on several occasions, the endocrine function of the post‐ovulatory follicle (corpus luteum) is only well understood in eutherian mammals. In this report we present evidence that the corpus luteum is a phylogenetically ancient endocrine organ, which secretes progesterone in response to pituitary hormones in a representative of the oldest extant jawed vertebrate (the dogfish, Squalus acanthias). Corpora lutea from pregnant aplacental viviparous spiny dogfish, Squalus acanthias, were removed, weighed and incubated in Eagle's Basal Medium supplemented with glutamine and urea for between 4 and 8 h at 18°C in 95% oxygen and 5% carbon dioxide. Corpora lutea decreased in weight from early to late pregnancy. Using radioisotopic methods, progesterone was definitively identified as a product of stage C corpora lutea. Basal progesterone synthesis, measured by radiommunoassay, increased from 301 ± 11.8 pg/mg/ corpus luteum/4 h in stage A of pregnancy to 1,881 ± 162.7 at stage B, and decreased markedly as corpora lutea decreased in size (stage C, 179 ± 19.2; stage D, 12 ± 3.2). An aqueous extract equivalent to one twenty‐fifth of the gonadotropic ventral lobe of the pituitary markedly stimulated progesterone in the incubates of stage C corpora lutea but not other stages. Corpus luteum function as an endocrine organ appears to be an ancient mechanism which antedates the appearance of terrestrial vertebrates.
Solute effects on the glycine cleavage system of two osmoconformers (Raja erinacea and Mya arenaria) and an osmoregulator (Pseudopleuronectes americanus)
Authors: Moyes Christopher D. , Moon Thomas W. 
Published: June 2005

AbstractThe effects of several organic solutes on the activity of the mitochondrial enzyme complex known as the glycine cleavage system (GCS) were examined in two osmoconforming species (soft‐shelled clam, Mya arenaria and little skate, Raja erinacea) and an osmoregulator (winter flounder, Pseudopleuronectes americanus). Taurine, beta‐alanine (BALA), and proline, compatible solutes which typically have no effect on enzyme function, significantly affected GCS activity with pronounced interspecific differences in sensitivity evident. Urea had no effect on skate GCS activity but significantly inhibited the enzymes from clam and flounder. The methylamines, trimethylamine oxide (TMAO) and betaine, did not significantly affect GCS from any species examined. Sarcosine significantly inhibited GCS from all three species, although this response may be of a regulatory nature. Inhibition of flounder GCS by urea was overcome by TMAO when these solutes were added in a 2:1 ratio (urea:TMAO). Pronounced inhibition of skate GCS occurred in response to urea + TMAO (2:1), whereas neither solute added alone had an effect on GCS activity. Although significant interspecific differences in solute effects occurred, each osmoconforming species was less sensitive to its own native osmolytes. BALA, however, stimulated skate GCS and may be important in enhancing sarcosine oxidation during hypoosmotic stress. The potential physiological significance and biochemical implications of these solute effects are discussed.
Developmental fate in chimeras derived from highly asynchronous murine blastomeres
Authors: Prather Randall S. , First Neal L. 
Published: June 2005

AbstractThe developmental fate of single blastomeres from eight‐cell murine embryos reaggregated with intact two‐cell embryos was evaluated after culture. Fluorescein isothiocynate was used to follow developmental fate in preblastocyst chimeric embryos. Expression of stage‐specific embryonic antigen 3 was used to assay developmental fate at the blastocyst stage, and glucosephosphate isomerase variants were used to assay at the blastocyst stage and after implantation. The results suggest that the descendents of the 1/8 component stay in a patch area and do not selectively migrate to the inner cell mass (ICM). This is in contrast to many studies that indicate that smaller blastomeres, which are more advanced in development, migrate to the ICM. The differences in experimental designs are discussed. Possible mechanisms for this phenomena are that the eight‐cell blastomere is physically excluded from the ICM by position or polarization, or that it is differentiating ahead of the two‐cell component and becomes trophectoderm.