摘要:

AbstractThe modulatory effects of exogenous applications of adenosine on luminous organs (photophores) of the fishPorichthyswere studied. Pretreatment of photophores with adenosine (10−7to 10−3M) potentiated both phases of adrenaline induced luminescence. The first peak of light (Lmax1) showed a 3‐fold increase following 10−7M adenosine treatment; a maximal increase of 12‐fold was observed with 10−3M adenosine. The second peak of light (Lmax2) exhibited a similar dose‐response curve, but the maximal increase was attained with 10−4M adenosine. The potentiating effect of 1 uM adenosine on light emission triggered by adrenaline increased for adrenaline concentrations ranging from 10−7to 10−4M for Lmax1, but it remained stable for Lmax2. All 4 P1‐purinergic agonists tested at the final concentration of 10−4M induced a potentiation of adrenaline luminescence with the following rank of potency: L‐PIA>NECA>CADO ≥ CHA = ADO for Lmax1 and NECA>CADO>ADO>CHA>L‐PIA for Lmax2. The potentiating effect of adenosine was antagonized with the following rank of potency by the P‐1 purinergic antagonists: CPT>DPMX ≥ AMINO>THEO for Lmax1 and CPT>AMINO>THEO ≥ DPMX for Lmax2. According to the classification of purinergic receptors, our results suggest that P1‐purinergic receptors might be implicated in the adenosine potentiation ofPorichthysadrenaline luminescence. Experiments also showed that nor‐adrenaline luminescence is inhibited by 1 uM adenosine pretreatment. Further work will be necessary to elucidate the mechanism involved in the modulatory roles played by the purinergic receptors on adrenaline and noradrenaline luminescence inPorich

ISSN:0022-104X    

DOI:10.1002/jez.1402660102

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1993

数据来源: WILEY

摘要:

AbstractThe present study was done to elucidate the mechanism(s) by which calcium is taken up or transported across the yolk sac membrane of the embryonic chick. We examined the effect of various inhibitors or experimental conditions on the uptake of calcium in vitro. Treatment with ouabain, verapamil, antimycin A and calcium ionophore A23187; substitution of choline for sodium or potassium in the buffer; or incubation of the tissue at 0°C had no significant effect on calcium uptake by the yolk sac membrane. Dinitrophenol (DNP) and lanthanum chloride (LaCl2) reduced45Ca uptake from day 6 and 9 embryos by 15% and 30%, respectively. Cytochalasin B decreased the uptake of45Ca in yolk sac membrane disks of day 6 embryos, but not in older embryos. The effects of cytochalasin B were explored further in embryos pretreated with either 1,25(OH)2D3or PTH, both of which enhance calcium uptake. Cytochalasin B decreased calcium uptake in 9‐day and 12‐day vitamin D‐treated embryos to about 60% of their hormone‐enhanced level and also decreased PTH‐stimulated45Ca uptake into yolk sac disks by about 50% in embryos of all age groups tested.We also examined the effect of cytochalasin B on45Ca transport across the yolk sac membrane in vivo. Cytochalasin B did not affect this transport in control (vehicle‐treated) embryos. However, it significantly decreased the enhanced in vivo45Ca transport in day‐9 and ‐12 vitamin D‐treated embryos approximately 30% and 45%, respectively. Additionally, cytochalasin B decreased the transport of calcium from yolk to blood by about 40% in PTH‐treated day‐9 embryos. These results indicated that both calcium uptake and transport by hormone‐stimulated yolk sac membranes involves endocytosis but that some other mechanism(s) must also be involved

ISSN:0022-104X    

DOI:10.1002/jez.1402660103

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1993

数据来源: WILEY

摘要:

AbstractIntestinal eosinophilic granule cells (EGCs) of the rainbow trout (Oncorhynchus mykiss) have been likened to mammalian mast cells and degranulate in response to stimulation by capsaicin and substance P. This investigation was conducted to examine the effects of capsaicin and substance P on the trout intestinal EGC population and to quantify the different morphologies following systemic administration. Rainbow trout were injected intraperitoneally with capsaicin, substance P, serotonin, or vehicle controls (0.5 ug/g body weight). Fish were killed at timed intervals and the mid intestine was processed for light and electron microscopy. The number of EGCs which could be observed in the stratum compactum was quantified for each treatment over the time course of the experiment. EGCs could be classified ultrastructurally into 1 of 5 categories based on their granule morphology. The cell frequencies and relative proportion of each cell class were analyzed statistically. The frequency of EGCs in the stratum compactum of fish injected with capsaicin or substance P significantly decreased post‐injection (P<0.05) compared to controls (saline‐ and BSA‐injected fish). Serotonin had no effect on EGC frequency, morphology, or distribution as compared with saline. Stimulation with capsaicin and substance P resulted in time‐dependent changes in both EGC granule morphology and distribution within the intestinal mucosa. Following an apparent migration of EGCs to the lamina propria and degranulation, small granuled EGC‐like cells appeared first in the lamina propria and then later in the stratum compactum. The significance of the stratum compactum as a depot for intestinal EGCs and the site for EGC maturation is discussed. © 1993 Wiley

ISSN:0022-104X    

DOI:10.1002/jez.1402660104

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1993

数据来源: WILEY

摘要:

AbstractAn enzyme‐linked immunosorbent assay (ELISA) was developed to detect vitellogenin in skates. The antibody raised against the yolk protein lipovitellin was shown to recognize a sexspecific, estrogen‐inducible 205 kD protein in plasma, previously identified in skate as vitellogenin. The detection limit of the assay was 31.3 ng/ml, similar to that of radioimmunoassays for vitellogenin detection in other species. Using the assay, vitellogenin levels were shown to be highest (241.8 ± 26.5 ug/ml) in the ovarian follicular phase, decreasing approximately 1‐2 days before ovulation to a low (173.1 ± 22.9 ug/ml) during the luteal phase. Vitellogenin levels increased again approximately 1‐2 days before oviposition to 259.8 ± 38.8 ug/ml.The effects of estrogen and progesterone on hepatic vitellogenin production in normal and hypophysectomized male skates were also investigated. Plasma vitellogenin was not detectable in either intact or hypophysectomised male skates, but increased with estradiol treatment (intact: 48.2 ± 4.9 ug/ml vs. hypophysectomised 252 ± 10.6 ug/ml at day 8). Progesterone treatment significantly (P<.01) attenuated the effect of estrogen on plasma vitellogenin levels in both intact (17 ± 2.1 ug/ml) and hypophysectomized (44.0 ± 9.4 ug/ml) male skates. © 1993

ISSN:0022-104X    

DOI:10.1002/jez.1402660105

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1993

数据来源: WILEY

摘要:

AbstractCultures of both isolated and conjugated explants from early gastrulae ofBufo arenarumwere prepared for a study of the development of ventral mesoderm. Only combinations including components of the deep ventral marginal zone and the animal pole successfully differentiated into blood cells (erythrocytes). Histological studies indicated that, while prospective mesodermal cells constituted the only source of such cells, prospective ectodermal cells provided the necessary stimulus for this kind of differentiation. Differentiated cultures, in which the tracer of cell‐lineage fluorescein dextran amine was used to label these components, confirmed the above conclusions. These findings are discussed in the context of current concepts about the formation of mesoderm. © 1993 Wiley‐Liss,

ISSN:0022-104X    

DOI:10.1002/jez.1402660106

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1993

数据来源: WILEY

摘要:

AbstractChimeric rainbow trout embryos have been produced by injecting isolated blastomeres into intact recipient blastulae. In order for chimeric fish to be useful in studies of development, it is necessary to determine whether the various organs or tissues of the resultant chimera have an equal probability of arising from the injected cells derived from donor embryos. The objective of this investigation is to determine the proportion of cells in the blood, liver, and brain tissues of rainbow trout chimeras that are derived from the injected cells. Blastomeres isolated from normal diploid blastulae were microinjected into age‐matched triploid recipient embryos, and the treated embryos grown until 4 weeks post hatch. Samples of blood, liver, and brain tissues were dispersed; the cell nuclei were labeled with propidium iodide, and the samples subjected to flow cytometric analysis to determine the proportions of diploid and triploid nuclei. The proportion of cells that were diploid varied among the resultant chimeric trout. Analysis of variance on the proportion of diploid cells in each sample indicated that there was no significant effect of tissue type. These results support the hypothesis that the isolated cells of the donor embryo are no more likely to colonize one tissue or organ type of a chimera than another. © 1993 Wiley‐Liss,

ISSN:0022-104X    

DOI:10.1002/jez.1402660107

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1993

数据来源: WILEY

摘要:

AbstractDiploid and triploid hybrids, consisting of the various combinations of chromosome set and cytoplasm betweenRana nigromaculataandRana lessonae, were generated in order to study their viability and reproductive capacity. Reciprocal diploid hybrids and allotriploids, which had twolessonaegenomes and onenigromaculatagenome innigromaculatacytoplasm, all died without closing their neural folds. Allotriploids, which had twonigromaculatagenomes and onelessonaegenome innigromaculatacytoplasm, all grew into healthy mature males in 12.4% (21 frogs) of zygotes. Following the elimination oflessonaechromosomes, ten of these males produced many spermatozoa containing a haploid set ofnigromaculatachromosomes. Other allotriploids, which had either onenigromaculatagenome and twolessonaegenomes or twonigromaculatagenomes and onelessonaegenome inlessonaecytoplasm, exhibited slightly improved viability. © 1993 Wiley‐Liss, I

ISSN:0022-104X    

DOI:10.1002/jez.1402660108

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1993

数据来源: WILEY

摘要:

AbstractIn the medaka, movement of spermatozoa and changes in the egg micropyles during fertilization were observed through a video camera and recorded with a video recorder to analyse sperm movement. Movement of spermatozoa as they entered micropyles in both intact and isolated chorions was compared before and after fertilization of the eggs. The inner one third of the micropyle was completely closed and the micropylar vestibule became shallow by 5 min after sperm attachment. Spermatozoa did not increase in swimming speed in the vicinity of the micropyle and were not attracted to it. The majority of spermatozoa entering the micropyle were rotating at an average frequency of 8 Hz in the right‐hand direction. The rotation direction did not correspond to the left‐hand spiral structure of the micropylar wall, though a small amplitude of the beating sperm flagellum corresponded with the narrow micropylar canal. The frequency of sperm entry into the micropyle decreased significantly in intact eggs and isolated chorions following fertilization, independent of artificial occlusion of the micropylar canal. Moreover, in isolated chorions before fertilization, spermatozoa rarely entered the micropylar canal from its inner aperture. The present data suggest the existence of some substance in the micropyle which guides spermatozoa into the micropylar canal, although the perimicropylar depression might also play a role in the guidance of spermatozoa. © 1993 Wiley‐Lis

ISSN:0022-104X    

DOI:10.1002/jez.1402660109

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1993

数据来源: WILEY

摘要:

AbstractA major regulatory site for species specificity of fertilization in mammals lies at the level of sperm binding to the zona pellucida. This implies a high degree of complementarity between gamete receptor molecules. One putative receptor molecule on spermatozoa is proacrosin/ acrosin which binds to zona pellucida glycoproteins (ZPGPs) non‐enzymically and with high affinity. The mechanism of recognition involves polysulphate groups in a particular stereochemical orientation and it has been suggested that this may contribute to species specificity of sperm‐egg binding. In the present work this hypothesis has been tested by challenging125I‐labelled ZPGPs from pig, cow, and hamster eggs to recognize heterologous sperm proacrosins as well as a variety of sequencerelated and unrelated proteins. Results show that pig and cow125I‐ZPGPs bind readily to boar, ram, and bull proacrosin but do not recognize guinea‐pig proacrosin or any of the polysulphate binding proteins from rat, hamster, or mouse spermatozoa. Hamster125I‐ZPGPs also recognise boar, ram, and bull proacrosin as well as a range of unidentified proteins in pH3 extracts of hamster, rat, and mouse spermatozoa. The binding of ZPGPs to a variety of proteins not related to proacrosin is strongest to those with a high content of basic residues (i.e., pI>8.5), although the secondary folding of the target protein is of major importance as boar proacrosin (pI 6.75) has the highest binding capacity of all proteins tested. Cross‐reaction of ZPGP probes was not observed to guinea‐pig proacrosin, suggesting that in this species the conformation of the protein is different to other sperm proacrosins. These results suggest that there are significant differences in the affinity of ZPGP‐proacrosin and ZPGP‐protein interactions to contribute to species specificity of sperm‐egg binding.

ISSN:0022-104X    

DOI:10.1002/jez.1402660110

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1993

数据来源: WILEY

摘要:

AbstractUndefined follicular factors that may influence nuclear maturation and/or cytoplasmic maturation are required during in vitro maturation of pig oocytes. Epidermal growth factor (EGF), insulin‐like growth factor‐I (IGF‐I), and dialysed porcine follicular fluid (dpFF) were evaluated for their effects on porcine oocyte nuclear maturation in vitro. In Experiment I, eight different maturation media were made in a split‐plot factorial design with dpFF (0% vs. 10% v/v dialyzed pFF) as the whole plot component, and EGF (0.0 vs. 50 ng/ml) and/or IGF‐I (0.0 vs. 100 ng/ml) as the factorial subplot component. Experiment II was a complete factorial design with dpFF and EGF. Pig follicular granulosa‐cumulus‐oocyte complexes (GCOC) were obtained from slaughterhouse ovaries, washed, and cultured at 38.5°C in a humidified incubator with 5% CO2in air for 42 h. Following culture, GCOC were mechanically stripped of granulosa‐cumulus cells and evaluated for nuclear maturation by light microscopy. In Experiment I, the percentage of Metaphase II oocytes for control, IGF‐I, EGF, and IGF‐I + EGF treatments without pFF were 50.7%, 52.6%, 80.9%, and 84.3% (control and IGF‐I groups significantly less,P<.001). The same treatments in the presence of pFF were similar and high (84.2, 84.9, 82.1, and 86.8%, respectively). Experiment II gave similar results. These results demonstrate that EGF, in the absence of pFF, promotes a similar level of oocyte nuclear maturation as does pFF alone or pFF with EGF and/or IGF‐I. IGF‐I does not appear to influence nuclear maturation of GC

ISSN:0022-104X    

DOI:10.1002/jez.1402660111

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1993

数据来源: WILEY