bluuebunny/crossref_metadata_2025_split huggingface dataset:
Protein synthesis involvement in regulating pituitary‐induced progesterone levels in ovarian follicles of Rana pipiens
Authors: Petrino Teresa R. , Schuetz Allen W. 
Published: June 2005

AbstractInvolvement of protein synthesis in frog pituitary hormogenate (FPH)‐induced progesterone production and/or accumulation in ovarian follicles was investigated. In amphibians, cycloheximide (C), an inhibitor of protein synthesis, inhibits progesterone and FPH‐induced germinal vesicle breakdown (GVBD). However, the site and mechanisms of action of cycloheximide within ovarian follicles have not been elucidated. Intrafollicular progesterone produced by FPH is considered to mediate oocyte maturation; thus, cycloheximide may interfere with production and/or action of progesterone. Simultaneous treatment of FPH‐stimulated follicles with cycloheximide inhibited FPH‐induced progesterone accumulation (measured by RIA) and the accompanying‐GVBD in a dose‐dependent fashion. Inhibitory effects of cycloheximide on either FPH‐induced progesterone production or GBVD were not reversed when follicles were washed and returned to fresh medium devoid of FPH and cycloheximide. However, subsequent restimulation of washed follicles with FPH resulted in increased progesterone levels and oocyte maturation. The extent of reversibility, in terms of GVBD and progesterone production, after FPH restimulation varied between animals. Pretreatment of follicles with cycloheximide for 6 hours, without FPH, had little or no effect on progesterone production when follicles were washed and treated with FPH. Delayed addition of cycloheximide to follicles following FPH stimulation blocked further progesterone accumulation as indicated by measurement of intrafollicular progesterone at the time of cycloheximide addition and at the end of the incubation period. The results indicate that cycloheximide rapidly inhibits progesterone production and that continuous protein synthesis is required for progesterone accumulation. Furthermore, protein synthesis does not appear to be required for progesterone metabolism since intrafollicular progesterone declined with prolonged culture even in the presence of cycloheximide. The nature of protein(s) involved in follicular progesterone production remains to be elucidated. FPH mediation of oocyte maturation within ovarian follicles appears to depend upon protein synthesis in somatic follicle cells, which is required for progesterone production, and in the oocyte, to mediate the response to the steroid trigger.
An analysis of the influence of thyroid hormone on the synthesis of proteins in the tail fin of bullfrog tadpoles
Authors: Ray L. Bryan , Dent James Norman 
Published: June 2005

AbstractBy incubation of explants of tail fin from tadpoles of Rana catesbeiana in a solution of 35S‐methionine for 4 h, newly synthesized proteins were labeled isotopically. After separation by two‐dimensional polyacrylamide gel electrophoresis, those proteins were visualized by fluorography. Exposure of explants to culture medium containing thyroxine (T4) (150 nM) increased the incorporation of 35S‐methionine into several proteins with 48 h. Effects of T4 on the relative abundance of two of these newly synthesized proteins were detected after 8 h of hormonal treatment. Very similar patterns of newly synthesized proteins were observed when proteins from explants of tail fin removed from tadpoles at metamorphic climax and immediately incubated with 35S‐methionine were compared with proteins produced in fin derived from premetamorphic animals. These results are interpreted to indicate that both treatment of explants with T4 and elevation of endogenous levels of thyroid hormones during spontaneous metamorphosis increased the relative rates of synthesis of several identical proteins. The potential involvement of those proteins in early phases of metamorphic action which eventually lead to cell death and resorption is discussed.
An ovary‐stimulating factor in the shrimp, Paratya compressa
Authors: Takayanagi Hiroshi , Yamamoto Yoshihiro , Takeda Naokuni 
Published: June 2005

AbstractThe present study examined in vivo and in vitro the effects of extracts of the central nervous system (brain and thoracic ganglion) and muscle tissue on ovarian development in the shrimp, Paratya compressa. Both the brain and thoracic ganglion extracts stimulated vitellogenesis in oocytes. In particular, the brain extracts especially were more effective than those of thoracic ganglion in inducing this response. The extracts of muscle tissue did not have any effect on the ovaries. These results demonstrate that an ovarystimulating factor in the central nervous system may act directly in ovarian vitellogenesis.
Hypocalcemic effects of bovine parathyroid hormone (1–34) and stannius corpuscle homogenates in teleost fish adapted to low‐calcium water
Authors: Bonga S. E. Wendelaar , Pang R. K. , Pang P. K. T. 
Published: June 2005

AbstractInjections of bovine parathyroid hormone (PTH 1–34) and homogenates of corpuscles of Stannius produce hypocalcemia in male killifish and tilapia adapted to calcium‐deficient seawater or fresh water, respectively. In fish from water with normal calcium concentrations no effects are noticeable. These results suggest similarity in bioactivity between PTH, the hypercalcemic hormone of terrestrial vertebrates, and the hypocalcemic factor of the corpuscles of Stannius in teleost fish.
Regulation of motility in sperm of the red‐spotted newt
Authors: Hardy Matthew P. , Dent James Norman 
Published: June 2005

AbstractThe motility of sperm was examined in vivo in the vas deferens, the spermatophore, and the spermatheca of the red‐spotted newt and in in vitro preparations with variations in osmolality, hydrogen ion concentration, and concentrations of specific osmolytes. Sperm were motile within the spermatophore, but little or no evidence of motility was seen in the spermatheca or the vas deferens. Approximately 25% of sperm from the vas deferens became motile when dispersed in spermatic fluid plasma, the sperm‐bearing liquid of the vas deferens, indicating crowding to be a possible motion‐restraining factor. Fewer than 50% were motile in several saline media isosmotic with spermatic fluid plasma, whereas more than 90% became motile in distilled water or media at osmolalities near that of pond water. Motility in isosmotic solutions persisted beyond 12 hours, but at low osmolality ceased by 6 hours. When dispersed at higher osmolalities initial motility was low but increased to isosmotic levels by 12 hours. Responses to immersion in solutions of mannitol were similar to ones observed in saline solutions of equivalent osmolality. Dispersion in hydrogen ion concentrations between pH 4 and 9 did not affect the initial motility of sperm, but after 12 hours at pH 9, pH 4 or 5 movement was inhibited. In general, these data indicate a major role for osmolality in the enforced quiescence of sperm during storage and demonstrate that the low osmolality of pond water is primarily responsible for the activation of sperm in the spermatophore of the newt.
Pressure‐adaptive differences in proteolytic inactivation of M4‐lactate dehydrogenase homologues from marine fishes
Authors: Hennessey John P. , Siebenaller Joseph F. 
Published: June 2005

AbstractThe inactivation by hydrostatic pressure of muscle‐type lactate dehydrogenase (M4‐LDH, EC 1.1.1.27; L‐lactate: NAD+ oxidoreductase) homologues from five shallow‐living and six deep‐living marine teleost fishes was compared. The pressures which inactivate these enzymes are much higher than the pressures experienced by any of the species. To determine whether hydrostatic pressure effects on protein aggregation state and conformation might influence proteolysis, the inactivation of LDH by the proteases, trypsin (EC 3.4.21.4) and subtilisin (EC 3.4.4.16) was determined at atmospheric pressure and 1,000 atm pressure. At 10°C and atmospheric pressure, the enzymes of the shallow‐living fishes are inactivated four times faster by trypsin and three times faster by subtilisin than are the homologues of the deep‐living species. At 1,000 atm pressure, the homologues of shallow‐occurring fishes were inactivated 28 to 64% more than predicted from the summed effects of denaturation by 1,000 atm pressure and tryptic inactivation at atmospheric pressure. In contrast, the homologues of the deep‐sea species were inactivated by trypsin 0 to 21% more than expected. At 1,000 atm, inactivation by subtilisin increased to a similar degree for enzymes from both deep‐ and shallow‐living species. However, at 1,000 atm, the M4‐LDH homologues of the deep‐sea species lost less activity (55.3%) than did the homologues of the shallow species (86.4%). In comparisons made at 200 atm, a pressure typical of the habitat of the deep‐occurring species, tryptic inactivation of the LDH of the shallow‐living Sebastes melanops was increased 14%. No pressure inactivation of the enzyme is evident at 200 atm. Two hundred atm pressure does not increase the tryptic inactivation of the enzymes of the two deep‐living macrourids. Increased structural stability of the enzymes of deep‐sea species may be an adaptation which prevents too rapid protein turnover, which would be energetically costly in the food‐poor deep sea.
Innervation pattern and responsiveness of melanophores in tail fins of teleosts
Authors: Miyata Seiji , Yamada Koji 
Published: June 2005

AbstractThe pattern of adrenergic innervation to melanophores in split tail fins of the goby, Tridentiger obscurus, and the guppy, Lebistes reticulatus, was investigated using 3H‐norepinephrine (3H‐NE) by light microscopic autoradiography. In goby fins, comparatively thick nerve bundles labeled with 3H‐NE ran approximately parallel to fin rays. Thin varicose fibers which branched out from the thick bundles formed rough plexuses around individual melanophores. In guppy fins, no thick nerve bundles could be observed, but numerous thin varicose fibers ran between fin rays, forming dense nerve plexuses on individual melanophores. In setioned preparations of guppy fins, the 3H‐labeled neural elements were observed to be in close contact with both surfaces of the cells (i.e., those facing the epithelial cell layer and the split side of fins), while in goby fins, the neural elements could be found only on the epithelial surface of the cells. Usually, melanophores in freshly isolated guppy fins responded with a full aggregation of pigment to isotonic KCl and maintained the state during the repetitive administration of the medium. Meanwhile, the degree of pigment‐aggregation response of goby melanophores to isotonic KCl decreased considerably during the treatment. The difference in the mode of melanophore response to K+ between two fish species was considered to be due to the difference in the density of neural elements around each melanophore and, probably as a consequence, in the amount of released neurotransmiter which acts on the cells.
Autonomous fluorescence of eggs of the ascidian Ciona intestinalis
Authors: Deno Takuya 
Published: June 2005

AbstractUnder ultraviolet illumination, eggs of the ascidians Ciona intestinalis and C. savignyi were found to emit specific autonomous fluorescence in the myoplasmic region of egg cytoplasm, the vacuoles of test cells, and the follicular vesicles of follicle cells. The fluroescent egg cytoplasm formed a crescent after ooplasmic segregation and was distributed mainly to presumptive muscle cells. The fluorescence of the test cells appeared at early stages of oogenesis and remained constant during oogenesis and embryogenesis. The number of test cells within the perivitelline space of Ciona unfertilized eggs was estimated to be 1,154 ± 182 (S.D.); at the tailbud stage the number was 1,089 ± 149 (S.D.). These counts suggest that there is no proliferation of test cells from fertilization to at least the tailbud stage. The fluorescence of follicle cells also appeared at early stages of oogenesis and did not change during embryogenesis. The number of follicle cells attached to the chorions of eggs was estimated to be 63 ± 8 (S.D.).
Pregnancy‐associated esterase in sera of baboons
Authors: Cheng M.‐L. , Kuehl T. J. , Vandeberg J. L. 
Published: June 2005

AbstractBaboon serum samples were resolved by starch gel electrophoresis and polyacrylamide gradient gel electrophoresis and stained with naphthol substrates for esterase activity. An esterase that hydrolyzed α‐naphtyl butyrate in preference to α‐naphthyl acetate was found in very high activities in some individuals but not others. It migrated just cathodal of the albumin band in starch gels. In polyacrylamide gradient gels, it co‐migrated with albumin and had an apparent molecular weight of approximately 65,000 daltons. Electrophoretic analysis by gel electrophoresis of random serum samples from male and female baboons indicated that this esterase was present only in the sera of pregnant baboons. Further investigation of serial samples collected from carefully monitored baboons confirmed that the amount of activity of this esterase was correlated with stage of pregnancy. Therefore, it was named pregnancy esterase (PE). PE was detectable by gel electrophoresis and chromogenic staining techniques as early as day 30 of pregnancy; its activity gradually increased with progressive pregnancy and reached maximum activity near full term (182 days). Soon after parturition, the activity of PE decreased rapidly and was not detected in maternal sera by day 14 postpartum. No evidence of PE was detected in sera of pregnant humans.
Gill morphology and sodium influx in the rainbow trout (Salmo gairdneri) acclimated to artificial freshwater environments
Authors: Avella Martine , Masoni Armand , Bornancin Michel , Mayer‐Gostan Nicole 
Published: June 2005

AbstractBranchial sodium uptake was measured across secondary lamellae (SL) using the isolated‐perfused head preparation. This study was correlated with histological examination.Freshwater trout, Salmo gairdneri, were exposed to various artificial media: distilled water (DW), fresh water (FW: NaCl < 200 μl/1; Ca++ = 1.5 mM/1), FW + 5 mM CaCl2 and FW + 10 mM CaCl2. These environments altered the number and forms of “chloride cells” (CC) located in SL and were related to changes in maximal transport rate of Na+. An increase in a specific type of CC (round) was associated with an increase in Vmax, and a decrease in round cells was associated with a decrease in Vmax.Relative to FW, exposure to DW increased the density of round cells, FW + 5 mM CaCl2 had no effect, and FW + 10 mM CaCl2 produced an initial degeneration of CC followed by restoration and increase in protruding round cells.We conclude that secondary lamellar chloride cells play an important role in Na+ uptake.
Studies on the mechanisms of neurulation in the chick: Morphometric analysis of the relationship between regional variations in cell shape and sites of motive force generation
Authors: Nagele Robert G. , Lee Hsin‐Yi 
Published: June 2005

AbstractMicrofilaments, which are organized into bundles in the apical ends of neuroepithelial cells, are generally thought to play a major role in generating the driving forces for neural tube closure. Because of their proximity to the luminal surface, the contractile activity of these microfilament bundles results in conspicuous changes in the overall shape of neuroepithelial cells, most notably apical costriction and apical surface folding. In the present study, we have used morphometric methods and computer‐assisted image analysis to reveal the distribution of microfilament‐mediated forces in the developing midbrain during initial contact of apposing neural folds in chick embryos at Hamburger and Hamilton stage 8+ of development (Hamburger and Hamilton (1951) J. Morphol., 88:49–92). The degree of apical constriction, apical surface folding, and bending of the neuroepithelium was used as a barometer of local microfilament activity. Results indicate that cells forming the floor and midlateral walls of the developing midbrain consistently show a higher degree of apical constriction and surface folding than those at other locations. These same regions of the neuroepithelium also exhibit the greatest degree of bending. We conclude that the principal driving forces for closure of the neural tube, at the level of the midbrain, are concentrated in certain regions of the neuroepithelium (i.e., the floor and midlateral walls of the forming neural tube) rather than uniformly distributed.
Intermittent erythropoiesis in anemic newts
Authors: Frangioni Giuliano , Borgioli Gianfranco 
Published: June 2005

AbstractA group of 88 newts, Triturus cristatus carnifex (Laurenti), was rendered totally anemic by administering acetylphenylhydrazine (APH) in the breeding water for 48 h at a concentration of 25 mg/liter. The course of erythron restoration was followed for 5 months, sacrificing four specimens per week and analyzing the blood and spleen hemopoietic tissue. The return to the normal values of the red blood cell count occurred through marked increases in concentration at fairly regular intervals, which is best explained by a discontinuous, rhythmic erythropoiesis. This fact is strictly correlated with the intermittent mitotic activity observed in the spleen and with the periodic appearance of large quantities of immature elements in the blood smears. The APH‐induced synchronization of newt erythropoietic activity revealed the approximate length of each erythropoietic cycle to be 4 to 5 weeks and the erythropoietic life span to be 50 to 60 days.
Artificial induction of selfing conjugation in Paramecium bursaria
Authors: Endoh Hiroshi , Watanabe Tsuyoshi , Hiwatashi Koichi 
Published: June 2005

AbstractIn normal conjugation of Paramecium bursaria, pairs always consist of cells of different mating types and no selfing pairs are induced with detached cilia from cells of a complementary mating type. This suggests that the initial ciliary agglutination (the mating reaction) is mating‐type specific but that the subsequent formation of conjugating pairs is not mating‐type specific as in the other species of Paramecium. The mechanism to exclude the formation of selfing pairs in normal conjugation is suggested to be the requirement of long‐lasting specific ciliary adhesion for the formation of firm pairs.
Energy allocation during concurrent pregnancy and lactation in Norway rats with delayed and undelayed implantation
Authors: Oswald Christine , McClure Polley Ann 
Published: June 2005

AbstractDespite the high cost of lactation alone, concurrent preganncy and lactation (CPL) is widespread among rodents. Many species that exhibit CPL delay implantation of the litter in utero while nursing. The first purpose of this study was to describe the pattern of energy allocation during CPL in a species with a large degree of overlap between gestation and lactation. Resting metabolic rate, food consumption and mass changes of Norway rat dams and litters, digestive efficiency and urinary energy loss of dams, and pup tissue energy equivalents were determined for CPL dams and for dams that were only lactating (C). CPL dams had significantly higher metabolic rates than C dams. Food consumption, pup growth, tissue energy equivalents, and assimilation efficiency were similar for both groups. The energy equivalent of mass change was greater for C dams, which gained in maternal mass (lipid) during lactation, than for CPL dams, which only increased in mass because of the litter in utero. The second purpose of this study was to investigate the suggestion that delayed implantation during CPL evolved as a mechanism to lower peak energy demands during CPL. Concurrently pregnant and lactating dams were injected with estrone (ECPL dams) on days 3–16 of lactation to prevent them from delaying implantation. A group of dams that were only lactating also received estrone injections (EC dams). ECPL dams produced smaller offspring at weaning than EC dams. This effect was more pronounced for large‐littered dams. These results indicate that the increased metabolic cost of a concurrent pregnancy is met by diverting energy into production of pup tissue rather than maternal tissue and that delayed implantation likely evolved as a means to decrease the peak energy demands of CPL.
Effects of FMRFamide on the intact and isolated circulatory system of the pinto abalone, Haliotis kamtschatkana
Authors: Krajniak K. G. , Bourne G. B. 
Published: June 2005

AbstractThe in vivo and in vitro effects of the molluscan tetrapeptide, FMRFamide, were examined on the circulatory system of the pinto abalone, Haliotis kamtschatkana. When perfused through isolated hearts, FMRFamide caused a dose‐dependent increase in heart rate. Injected into the circulation of intact, unrestrained animals, the peptide initially enhanced the rate of beating, augmented the aortic diastolic and pulse pressures, and raised the arteriovenous (AV) pressure difference; but at higher doses, this initial enhancement was followed by a decrease in aortic blood pressure, an increase in efferent ctenidial pressure, and a substantially reduced heart rate. Therefore, FMRFamide could have a role in controlling the circulation of H. Kamtschatkana.
Assessment of embryo viability prior to transfer by the noninvasive measurement of glucose uptake
Authors: Gardner David K. , Leese Henry J. 
Published: June 2005

AbstractAn ultramicrofluorometric technique was used to measure the uptake of glucose by single mouse blastocysts prior to transferring them into the uterus of pseudopregnant foster mothers. Of 50 blastocysts whose glucose uptake was measured prior to embryo transfer, 25 gave rise to male and 13 to female offspring. Twelve embryos failed to develop. The mean glucose uptake of these 12 embryos was significantly below that of those which developed successfully. Female embryos took up slightly more glucose than male embryos.
Effects of feeding and photocycle on diel changes in plasma thyroid hormone levels in rainbow trout, Salmo gairdneri
Authors: Cook R. F. , Eales J. G. 
Published: June 2005

AbstractIn rainbow trout held in the laboratory within a narrow temperature range on a 12L:12D photocycle and fed once during the photophase there was a marked diel change in plasma L‐thyroxine (pT4) and a less pronounced change in plasma 3,5,3′‐triiodo‐L‐thyronine (pT3). Both photocycle and feeding regimes were experimentally altered to determine their influence. During starvation there was no significant diel change in plasma T4 in fish held in continuous darkness or under a phase‐shifted (12D:12L) photocycle and minor fluctuations under a normal (12L:12D) photocycle, although phase‐shifting did generally depress pT4. Feeding caused a tonic elevation in pT4, a marked postprandial surge in pT4 and facilitated a T4 surge due to light in the early photophase. Under most of these conditions changes in pT3 were less pronounced and peak pT3 levels usually followed the pT4 peaks, suggesting peripheral T3 derivation from T4. In conclusion, trout held at constant temperature show a diel profile in pT4 determined by an interaction between the feeding and photocycle regimes and which in turn probably influences delayed and more modest diel changes in pT3.