bluuebunny/crossref_metadata_2025_split huggingface dataset:
Influence of the mucin coat on the survival of rabbit and mouse embryos stored at 0°c
Authors: Kasai M. , Hiraishi M. , Nureki I. , Zhu S. E. , Sakurai T. , Machida T. 
Published: September 2005

AbstractTo examine the factors affecting the survival of refrigerated embryos, rabbit and mouse morulae were stored at 0°C in modified phosphate‐buffered saline (PB1) or in PB1 containing 0.75 M sucrose. Survival was defined as the ability to develop into an expanded blastocyst in culture. The data was analyzed with special reference to the presence of a mucin coat around the embryos. When rabbit morulae were stored in isotonic PB1 for 2, 4, 6, and 8 days, survival rates were 98%, 88%, 85%, and 50%, respectively. However, if the mucin coat had been removed before storage, the rates were lower (95%, 75%, 36%, and 3%, respectively). Sucrose impaired the survival of rabbit morulae irrespective of the presence of the mucin coat. Only 11% of mouse morulae survived 2 days of storage in PB1 medium, but if the medium contained sucrose, survival rates after storage for 2, 3, 4, and 5 days were higher (83%, 55%, 31%, and 7%, respectively). To provide them with a mucin coat around the zona pellucida, mouse embryos were incubated in a rabbit oviduct. Survival rates of these embryos after storage in the presence of sucrose did not decrease over 4 days of refrigeration (98–92%), and the rates after storage for 5, 6, and 7 days were 65%, 40%, and 30%, respectively; embryos that had been stored for 5 days were transferred to recipient mice, and live young were born. Agar embedding of mouse morulae did not have the same effect as the mucin coat. These results show that the rabbit embryo mucin coat can protect refrigerated embryos, but in mouse morulae, this effect was manifest only when sucrose was present in the storage medium. © 1993 Wiley‐Liss, Inc.
Initiation of the human sperm acrosome reaction by thapsigargin
Authors: Meizel Stanley , Turner Kenneth O. 
Published: September 2005

AbstractPrevious studies have established that the mammalian sperm acrosome reaction (AR) is dependent upon an influx of extracellular Ca2+, but the involvement of a mobilizable store of intracellular Ca2+ has not been shown. In many other cells, the endoplasmic reticulum is the site of such a Ca2+ ‐store. Here, we show that thapsigargin, a highly specific inhibitor of the endoplasmic reticulum Ca2+ ‐ATPase Ca2+ ‐pump (and thus a mobilizer of intracellular Ca2+) in other cells, can initiate the AR in capacitated human sperm. Thapsigargin at concentrations from 50–500 nM significantly increased the AR to the same extent when incubated with capacitated sperm for 1 min (assayed by indirect immunofluorescence). Transmission electron microscopy confirmed the occurrence of normal morphologyin the AR initiated by thapsigargin. Thapsigargin (200 nM) did not initiate the AR in noncapacitated sperm. Inititation of the AR by thapsigargin apparently requires an influx of Ca2+ since 1 min preincubation with the calcium channel blockers La3+ (250 μM) or Ni2+ (250 μM) prior to addition of thapsigargin completely inhibits AR‐initiation. Mobilization of an intracellular Ca2+ ‐store by thapsigargin in capacitated human sperm may lead to an influx of extracellular Ca2+ and subsequently the AR. Putative sites for thapsigargin‐sensitive intracellular Ca2+ ‐stores in human sperm include the cytoplasmic droplet, the sperm nucleus and the acrosome. © 1993 Wiley‐Liss, Inc.
Auditory receptor organs in the forelegs of Gampsocleis gratiosa (Tettigoniidae): Morphology and function of the organs in comparison to the frequency parameters of the conspecific song
Authors: Lin Yuzhen , Kalmring Klaus , Jatho Martin , Sickmann Thomas , Rössler Wolfgang 
Published: September 2005

AbstractThe morphology and the physiology of the auditory receptor organs in the forelegs of the tettigoniid species Gampsocleis gratiosa were investigated in detail. According to the tonotopic organization of the receptor cells of the crista acoustica in bushcrickets the threshold curves of all receptors found in the organs were correlated with the morphology of the auditory receptor cells. This was done by arranging them in relation to their frequency tuning with the receptors along the chain of cells in both organs starting proximally with the extreme low frequency cell up to the highest ultrasonic cells at the distal end of the crista acoustica.This investigation reveals that the auditory receptor organs of Gampsocleis gratiosa possess a broard banded hearing threshold curve including very low frequency parts.Also the conspecific stridulatory song is very broard banded with extraordinarily low frequency components. Therefore the sender and the receiver of this species‐specific communication system seem to be well adapted to each other. © 1993 wiley‐Liss, Inc.
Comparison of motor patterns in larval and adult stage of a beetle, Zophobas morio
Authors: Kutsch W. , Urbach R. , Breidbach O. 
Published: September 2005

AbstractFor a holometabolous insect, the beetle Zophobas morio, several motor patterns were recorded, using EMGs, for several homologous metathoracic muscles of the larval and adult stage. In the larva, most muscles are employed during walking, while in the adult, only the remotor coxae muscle (M119) will be activated during leg movements. Segmental bendings of the larva are mainly due to contractions of the dorsal longitudinal muscles. For adults, the myogenically driven thoracic flight muscles display a phase preference within the wing‐beat cycle, resulting in not only a functional but also activity‐dependent classification of wing depressor and elevator muscles. Time interval histograms of the excitatory junctional potentials (ejp's) show several peaks separated by about 20 ms, representing the wing‐beat period. Application of chlordimeform (CDM), an agonist of the neuromodulator octopamine, elicits in adults longer “flight” sequences without wing movement. During such sequences the 20 ms modulation of the ejp intervals is missing. This points to wing‐beat dependent afferences involved in patterning of the output during normal flight. Application of CDM in the larva results in a tonic activation, which shows several similarities with the adult ‘flight’ without wing‐beat. This finding suggests that the basic neuronal circuitry underlying the imago's flight is present precociously, before the dramatic reorganization of the animal during metamorphosis. © 1993 wiley‐Liss, Inc.
Cyclic postural behavior in the crayfish, Procambarus clarkii: Properties of the pattern‐initiating network
Authors: Moore Darrell , Larimer James L. 
Published: September 2005

AbstractCrayfish exhibit complex cyclical adjustments in abdominal posture during certain forms of backward walking. An isolated nerve cord preparation was used to investigate the properties of the interneurons which direct this alternation of abdominal flexion and extension.The command function for this cyclic postural behavior appears to be the domain of a distributed network of multiple pattern‐initiating interneurons: each interneuron may be viewed as a command element within a command system. The cyclic pattern may be elicited by stimulation of small axon bundles pulled from the ventrolateral margins of any of the abdominal connectives. As few as one stimulus pulse to the axon bundle can elicit a single cycle of patterned output, although more pulses are generally necessary. This suggests some convergence or amplification step in the pattern‐initiating interneurons. The amplification may be accomplished by several pattern‐initiating interneurons that are coupled to one another and converge on pattern generating circuits in each ganglion. Evidence supporting this interpretation is presented.Experiments involving resection of the cord reveal that the pattern‐initiating signals transfer laterally across all of the abdominal ganglia, but the network contains a bias for descending signal conduction once a lateral transfer is made. This finding agrees with other results. For example, recordings from pattern‐initiating axon bundles at rostral and caudal locations in the abdominal nerve cord show several descending but only one ascending unit activated during cyclic pattern generation.We also show that an isolated ganglion is capable of producing the cyclic motor program, although the outputs are much weaker than those elicited in the intact abdominal cord. Therefore, the pattern‐initiating system is both central and distributed. © 1993 wiley‐Liss, Inc.
Hepatic extraction of circulating insulin and glucagon in brown trout (Salmo trutta fario) after glucose and arginine injection
Authors: Carneiro N. M. , Navarro I. , Gutiérrez J. , Plisetskaya E. M. 
Published: September 2005

AbstractTo investigate whether nutritional state and induced changes of plasma hormone levels may affect hepatic extraction of hormones, plasma levels of insulin and glucagon were measured in the portal vein, hepatic vein, and caudal vessel of brown trout, Salmo trutta fario. In spring, when fish were actively feeding, glucose (30 mg/100 g weight) injection was followed by a decrease in glucagon presented to the liver (11.7 ng/min vs. 34.3 ng/min) and in hepatic extraction of glucagon. As a result, systemic glucagon concentration remained unchanged. High circulation levels of insulin and its hepatic uptake remained unaffected by glucose. In autumn, when maturing fish were fasting, their systemic plasma insulin levels decreased from 6.9 ng/ml to 1.8 ng/ml. Injected glucose increased both insulin quantity presented to the liver (81.3 ng/min vs. 43.6 ng/min) and systemic concentration of insulin (4.0 ng/ml vs. 1.8 ng/ml). Glucagon levels and hepatic extraction of insulin and glucagon remained unchanged after glucose injection. Injection of arginine (139 mg/100 g) elevated plasma circulating levels of both peptides. However, their hepatic extraction (especially the extraction of glucagon) decreased as compared to the control fish. This resulted in very high levels of insulin (>20 ng/ml) and glucagon (3.8 ng/ml) in the systemic circulation of arginine‐treated trout. We conclude that hepatic uptake of pancreatic hormones in fish is a dynamic process depending on experimental as well as nutritional conditions. © 1993 wiley‐Liss, Inc.
Effects of ions and bioactive substances on ovarian contraction in Fundulus heteroclitus
Authors: Leonard Jill B. K. , Bartley Susan M. , Taylor Malcolm H. 
Published: September 2005

AbstractThe effects of potassium, calcium, angiotensin II, urotensin II, melatonin, gonadotropin releasing hormone analogue (GnRH‐a), and human chorionic gonadotropin (hCG) on in vitro ovarian smooth muscle contraction were observed in Fundulus heteroclitus. Calcium induced contractions and modified spontaneous contractions in a dose‐dependent manner. Potassium, angiotensin II and urotension II induced dose‐dependent contractions while melatonin, GnRH‐a and HCG had no observable effect on the system. These data highlight the integral role of calicum in ovarian contraction and suggest possible roles in reproduction for angiotensin II and urotensin II. © 1993 wiley‐Liss, Inc.
Purification and properties of the fatty acid‐binding VHDL from the hemolymph of the spider Eurypelma californicum
Authors: Stratakis Emmanoel , Fragkiadakis Georgios , Tentes Ioannis 
Published: September 2005

AbstractAn abundant, very high density lipoprotein (VHDL) was isolated from the hemolymph of male and female tarantula Eurypelma californicum. The purification procedure involved density gradient ultracentrifugation and gel permeation chromatography on Bio‐Gel A‐1.5m. The tarantula VHDL has a hydrated density of 1.23 gml−1 and contains 16.5% lipids. The native molecular mass determined by pore limit electrophoresis and gel permeation chromatography was 380 kDa, which differs from the molecular mass calculated for its SDS‐PAGE subunits (110 and 95 kDa, plus 16.5% lipids). The tetrameric structure of the VHDL is discussed. Both the 110 and the 95 kDa subunit are glycosylated, containing 1.8% carbohydrate, indicating that the difference in molecular mass between them is not due to the level of glycosylation. Treatment of VHDL with reducing agents (β‐mercaptoethanol) decreased the apparent molecular mass of the 110 kDa subunit, while the 95 kDa subunit was not affected, indicating the presence of intra‐molecular disulfide bonds in the 110 kDa subunit. Indeed, cyst(e)ine analysis showed that the molecule contains five disulfide bonds persubunit. Both subunits are antigenically similar, as demonstrated by immunoblotting. Amino acid analysis showed that the VHDL has a relatively high aromatic amino acid content, tyrosine, and phenylalanine (14.5%). Phospholipids (46%) and free fatty acids (35%) were the major lipid components of the VHDL, indicating that this protein is the principal free fatty acid carrier in the hemolymph. The capacity of the purified VHDL to accept free fatty acids from the hepatopancreas was demonstrated in vitro. Phosphatidylcholine (60%) and phosphatidylethanolamine (14%) were the predominant phospholipids. The possible multiple role of tarantula VHDL in carrying fatty acids and carbonic anhydrase is discussed. Fatty acid analysis showed that the fatty acids and non‐polar lipids predominantly contain saturated fatty acids, whereas the phospholipids contain unsaturated fatty acids. © 1993 wiley‐Liss, Inc.
Regulation of mealworm fat body glucose metabolism in vitro: Effects of natural and synthetic catabolic neurohormones
Authors: Mtioui A. , Moreau R. , Bahjou A. , Gourdoux L. 
Published: September 2005

AbstractGlucose metabolism by Tenebrio molitor larval fat body tissue was studied in vitro by means of a microradiorespirometric method and the effects of either natural or synthetic catbolic hormones were evaluated.The use of this microradiorespirometric method allowed us to measure glucose catabolism in small pieces of tissue with good sensitivity.The metabolic modifications (relative and absolute) induced in the activities of the pentose cycle and glycolysis‐Krebs cycle, by larval mealworm Corpora cardiaca (CC) purified extracts, were compared with those produced by synthetic locust AKH I and mammalian glucagon. These metabolic variations were evaluated by measuring total CO2 and by using either [1‐14C]glucose or [6‐14C]glucose molecules as substrates. The kinetics of 14CO2 production and the dose‐response curves of hormones were determined.The total expired CO2 increases significantly (17–26%) during treatment with all of the hormones studied.Modifications to the kinetics of the specific radioactivity and the cumulative yields of 14CO2 derived from [1‐14C]glucose and [6‐14C]glucose under the influence of each of the hormones were recorded. CC extracts and AKH I rapidly (15 min) diverted glucose from pentose cycle (−45%); glucose oxidation was increased (+ 26%), this effect appearing later (75 min). Mammalian glucagon rapidly and durably increased glucose catabolism both via the pentose cycle (+35%) and by the glycolytic pathway (+ 200%).
Association of pigmentary organelles, carotenoid droplets, with endoplasmic reticulum in goldfish xanthophores and swordtail fish erythrophores
Authors: Kimler Victoria A. , Tchen T. T. , Taylor John D. 
Published: September 2005

AbstractA modified procedure for whole mount transmission electron microscopy (WMTEM) was utilized, for electron microscopes with accelerating voltages of 80 to 100 kV, to view the outer 40% of goldfish (Carassius auratus [Linneaus]) xanthophores and swordtail fish (Xiphophorus hellerii [Heckel]) erythrophores. This viewing region covers most of the lamellae and all of the filopodia and cellular processes. In this region one can observe three of the four physiological states: pigment dispersing, pigment fully dispersed, and pigment aggregating. The pigment in the fourth state, fully aggregated, cannot be viewed because of thickness of the cell body and is not addressed in this report. In goldfish xanthophores and swordtail fish erythrophores, the primary pigmentary organelle, the carotenoid droplet, is not a discrete organelle but is either associated with or attached to an extended tubulovesicular structure. Carotenoid droplet translocations appear to be dependent upon external cues which result in the elongation or retraction of these tubulovesicular structures. Tubulovesicular structures are continous with membranous sacs, which we termed carotenoid bodies. Based upon DiOC6(3) staining for the endoplasmic reticulum, we propose that the tubulovesicular structure and the endoplasmic reticulum are the same organelles. By using inhibitors of microfilaments (cytochalasin B or D) and microtubules (nocodazole), we report results which suggest cytoskeletal involvement in the elongation or retraction of endoplasmic reticular cisternae. Results with the intermediate filament inhibitor, cycloheximide, demonstrated that intermediate filaments were eliminated from the cells. We believe that the results are inconclusive because cycloheximide primarily inhibits protein synthesis and any interpretation must be made with care. © 1993 wiley‐Liss, Inc.
Effect of melatonin on pituitary secretion of prolactin in vitro during delayed implantation and the periimplantation period in the spotted skunk
Authors: Rozell Marcia D. , Mead Rodney A. 
Published: September 2005

AbstractThe pars tuberalis of the western spotted skunk is the only region of the brain known to bind 2‐[125I]iodomelatonin, thus suggesting that this region of the pituitary might be essential in mediating the effects of melatonin in this species. Female skunks were killed during short‐and long‐day photoperiods. Hemisections of the adenohypophysis, with and without the pars tuberalis were cultured in the presence and absence of 10 nM melatonin to determine whether the pars tuberalis mediates the previously observed suppressive effects of melatonin on the seasonal increase in plasma prolactin leves in this species. Pituitaries obtained during long‐day photoperiods secreted significantly more prolactin than those obtained during the short‐day photoperiod. Melatonin had no effect on pituitary response to gonadotropin releasing hormone and failed to inhibit prolactin secretion during the 48 h culture period. However, melatonin significantly reduced the inhibitory effects of dopamine on prolactin secretion. The latter response was observed in both photoperiods and in the presence and absence of the pars tuberalis. These results suggest that the pars tuberalis does not mediate the inhibitory effect of melatonin on prolactin secretion in the absence of the hypothalamus. © 1993 wiley‐Liss, Inc.
Development of collared lemmings, Dicrostonyx groenlandicus, is influenced by pre‐ and postweaning photoperiods
Authors: Nagy Tim R. , Gower Barbara A. , Stetson Milton H. 
Published: September 2005

AbstractWe examined the role of pre‐ and postweaning photoperiod on postweaning development of collared lemmings. Lemmings were gestated and reared to weaning (19 days of age) in one of three photoperiods: 22L:2D (22 hr of light:2 hr of dark), 16L:8D, and 8L:16D. At weaning, lemmings were either maintained in their natal photoperiod or transferred to one of the other two photoperiods. At the termination of the experiment (10 weeks postweaning) data were collected on somatic characters (body weight, bifid claw width, pelage stage, and guard hair length), serum prolactin (PRL), and reproductive parameters (testes, seminal vesicle, and uterine weights). Somatic characters were predominately influenced by postweaning photoperiod, when that photoperiod was either long (22L:2D) or short (8L:16D). When lemmings were exposed to an intermediate postweaning photoperiod (16L:8D), development of somatic characters was significantly influenced by the preweaning photoperiod; animals reared in 8L:16D regarded 16L:8D as a long day, whereas those reared in 22L:2D regarded 16L:8D as a short day. Serum PRL responded to photoperiod changes, often reflecting either the increase or decrease in day length, rather than simply the absolute number of light hours per day. Whereas reproductive indices in both sexes were stimulated by transfer from short to long photoperiod, chronic exposure to long photoperiod inhibited male development. No other photoperiod manipulations significantly influenced reproductive parameters. These observations suggest that, in the collared lemming, the neural and/or humoral factors regulating somatic and reproductive characters differ in their response to photoperiod. These results also suggest that the postweaning responses to photoperiod are programmed by earlier (gestational and/or neonatal) photoperiod exposure of the mother and/or the neonates. © 1993 wiley‐Liss, Inc.
Acquisition of maturational competence in in vitro grown mouse oocytes
Authors: Hirao Yuji , Miyano Takashi , Kato Seishiro 
Published: September 2005

AbstractThe maturational competence of the in vitro grown mouse oocytes of various sizes was examined, and was compared to that of oocytes of equivalent chronological age which grew in vivo. Oocyte‐granulosa cell complexes isolated from 10‐day‐old female mice were cultured for 10 days in vitro in the presence of 2 mM hypoxanthine to maintain the meiotic arrest. When the in vitro grown oocytes were denuded and cultured for further 24 h in the hypoxanthine‐free medium, 9, 37, and 100% of oocytes of 60–64.5, 65–69.5, and over 70 μm in diameter underwent germinal vesicle breakdown (GVBD), respectively. Of those oocytes which underwent GVBD, 19, 37 and 68% of oocytes larger than 60, 65, and 70 μm progressed to metaphase II, respectively. No oocyte less than 60 μm resumed meiosis. The parallelism found in the oocyte size and maturational competence was similar to that of their in vivo counterparts collected from 20‐day‐old mice. A significant proportion of the in vitro grown oocytes, however, formed a pronucleus‐like structure(s) after maturation culture, indicating that they could not maintain a normal arrest at metaphase II. © 1993 wiley‐Liss, Inc.
Hemocyte differentiation in the shore crab (Carcinus maenas) could be accompanied by a loss of glycogenosynthesis capability
Authors: Loret Suzanne M. 
Published: September 2005

AbstractHemocytes of the shore crab (C. maenas) were tested for their capability to store glucose, by measurements of the glucose phosphorylating activity. The properties of this hexokinase did not reflect any hepatic role of blood cells for carbohydrate storage, since this kinase seemed not to act as a glucose sensor. Moreover, these cells did not release their glycogen in vitro, even in the presence of CHH (crustacean hyperglycemic hormone). These observations led us to reject the hypothesis considering crustacean blood cells as “circulating hepatocytes.”A study on separated hemocyte populations for their glycogen content and their ability to synthesize the polysaccharide in vitro provided preliminary results arguing for the connection of the three types of blood cells in a unique cell line. © 1993 wiley‐Liss, Inc.